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SECTION. 1. SHORT TITLE. This Act may be cited as ``Social Security Information Act of 1997''. SEC. 2. FINDINGS. Congress finds that-- (1) information regarding the solvency of the social security trust funds, and personal earnings and benefits estimates is vital for working Americans to plan a financially secure retirement; (2) over the next 35 years, the number of American people age 65 and older will double, while the number of people age 20 to 64 will increase by only 20 percent, and these demographic changes will have a significant impact on the future of the social security system; (3) simplified and accurate information regarding the social security system is needed to enable working Americans to understand and adjust to those demographic changes; (4) more than 50 percent of the workers in the United States do not have a pension and that percentage is increasing for younger age groups, 50 percent of families in the United States have less than $1,000 in net financial assets, and the median amount of savings among adults who are in their late 50s, the age of a worker facing immediate retirement, is still less than $10,000; (5) lack of information has, in part, caused poor financial planning for future retirement, resulting in insufficient savings; (6) the General Accounting Office reports that the Personal Earnings and Benefits Estimate Statements (PEBES) initiative is an important step towards better informing the public about the programs and benefits under the social security system, but extensive revisions to the PEBES are needed to ensure better understanding of that system and effective communication to the general public about that system; and (7) public awareness of the long-term financial soundness of the social security system will facilitate necessary reform of that system and increase public confidence in the system. SEC. 3. PURPOSES. The purposes of this Act are-- (1) to require the Commissioner of Social Security to provide simple and accurate information on the fiscal status of the social security trust funds and on the personal earnings and benefits estimates of all eligible individuals in order to allow working Americans to better plan their retirement; (2) to prohibit the use of any message or design relating to such information that may mislead or confuse the general public; and (3) to build public confidence in the social security system through the requirement of full disclosure and increased awareness of the fiscal soundness of the system. SEC. 4. INFORMATION REQUIREMENTS FOR STATEMENTS. (a) Information Requirements for Social Security Account Statement.--Section 1143(a) of the Social Security Act (42 U.S.C. 1320b-13(a)) is amended-- (1) in paragraph (2)-- (A) in subparagraph (B), by inserting ``, including a separate estimate of the amount of interest earned on the contributions,'' after ``disability insurance''; (B) in subparagraph (C)-- (i) by inserting ``, including a separate estimate of the amount of interest earned on the contributions,'' after ``hospital insurance''; and (ii) by striking ``and'' after the semicolon; (C) in subparagraph (D), by striking the period at the end and inserting a semicolon; (D) by redesignating subparagraphs (A), (B), (C), and (D) as subparagraphs (B), (C), (D), and (E), respectively; (E) by inserting after the matter preceding subparagraph (B), as redesignated by subparagraph (D), the following: ``(A) the name, age, gender, mailing address, and marital status of the eligible individual;''; (F) by adding at the end the following: ``(F) the total amount of the employer and employee contributions for the eligible individual for old-age and survivors insurance benefits, as of the end of the month preceding the date of the statement, in both actual dollars and dollars adjusted for inflation; ``(G) the projected value of-- ``(i) the aggregate amount of the employer and employee contributions for old-age and survivors insurance benefits that are expected to be made by or on behalf of the individual prior to the individual attaining retirement age, in both actual dollars and dollars adjusted for inflation; ``(ii) the annual amount of old-age and survivors insurance benefits that are expected to be payable on the eligible individual's account for a single individual and for a married couple, in dollars adjusted for inflation; ``(iii) the total amount of old-age and survivors insurance benefits payable on the eligible individual's account for the individual's life expectancy, in dollars adjusted for inflation, identifying-- ``(I) the life expectancy assumed; ``(II) the amount of benefits received on the basis of each $1 of contributions made by or on behalf of the individual; and ``(III) the projected annual rate of return for the individual, taking into account the date on which the contributions are made in the eligible individual's account and the date on which the benefits are paid; ``(iv) the total amount of old-age and survivors insurance benefits that would have accumulated on the eligible individual's account on the date on which the individual attains retirement age if the contributions for such individual had been invested in Treasury 10- year saving bonds at the prevailing interest rate for such bonds as of the end of the month preceding the date of the statement, in dollars adjusted for inflation, identifying-- ``(I) the date of retirement assumed; ``(II) the interest rate used for the projection; and ``(III) the amount that would be received on the basis of each $1 of contributions made by or on behalf of the individual; ``(H) the average annual rate of return, adjusted for inflation, on the Treasury 10-year saving bond as of the date of the statement; ``(I) the average annual rate of return, adjusted for inflation, on the Standard and Poor's 500, or an equivalent portfolio of common stock equities that are based on a broad index of United States market performance, for the preceding 25 years; ``(J) a brief statement that identifies-- ``(i) the balance of the trust fund accounts as of the end of the month preceding the date of the statement; ``(ii) the annual estimated balance of the trust fund accounts for each of the succeeding 30 years; and ``(iii) the assumptions used to provide the information described in clauses (i) and (ii), including the rates of return and the nature of the investments of such trust fund accounts; and ``(K) a simple 1-page summary and comparison of the information that is provided to an eligible individual under subparagraphs (G), (H), and (I).''; and (2) by striking paragraph (3) and inserting the following: ``(3) The estimated amounts required to be provided in a statement under this section shall be determined by the Commissioner using a general methodology for making such estimates, as formulated and published at the beginning of each calendar year by the Board of Trustees of the trust fund accounts. A description of the general methodology used shall be provided to the eligible individual as part of the statement required under this section. ``(4) The Commissioner of Social Security shall notify an individual who receives a social security account statement under this section that the individual may request that the information described in paragraph (2) be determined on the basis of relevant information provided by the individual, including information regarding the individual's future income, marital status, date of retirement, or race. ``(5) For purposes of this section-- ``(A) the term `dollars adjusted for inflation' means-- ``(i) dollars in constant or real value terms on the date on which the statement is issued; and ``(ii) an amount that is adjusted on the basis of the Consumer Price Index. ``(B) the term `eligible individual' means an individual who-- ``(i) has a social security account number; ``(ii) has attained age 25 or over; and ``(iii) has wages or net earnings from self- employment; and ``(C) the term `trust fund account' means-- ``(i) the Federal Old-Age and Survivors Insurance Trust Fund; and ``(ii) the Federal Disability Insurance Trust Fund.''. (b) Mandatory Provision of Statements.--Section 1143(c)(2) of the Social Security Act (42 U.S.C. 1320b-13(c)(2)) is amended by striking ``With respect to'' and all that follows. (c) Technical Amendment.--Section 1143 of the Social Security Act (42 U.S.C. 1320b-13) is amended by striking ``Secretary'' each place it appears and inserting ``Commissioner of Social Security''. (d) Effective Date.--The amendments made by this Act shall apply to statements provided for fiscal years beginning after the date of enactment of this Act.

Social Security Information Act of 1997 - Amends title XI of the Social Security Act to revise requirements for the social security account statements distributed annually by the Secretary of Health and Human Services. Requires such statements to include: (1) a separate estimate of the interest earned on employee and self-employment contributions for hospital insurance and old-age, survivors, and disability insurance; (2) specified information on the projected value of the aggregate amount of employer and employee contributions for old-age and survivors insurance, as well as annual and total amounts of benefits, in dollars adjusted for inflation; (3) the average annual rates of return on Treasury ten-year savings bonds and the Standard and Poor's 500; and (4) monthly and projected annual trust fund balances.

Disney’s newest animated film Finding Dory will threaten the population of Blue Tang Fish unless Disney takes action to protect it. After Finding Nemo came out, the demand for Clownfish as souvenirs spiked in the US. Fortunately, Clownfish can be bred in captivity, so the market has been partially fulfilled that way. But Blue Tang Fish cannot be bred in captivity, so there is no way to fill a demand in pet Blue Tang except pulling them from their natural habitat. If Disney does not place an explicit warning at the beginning of the film asking viewers not to adopt Blue Tang like Dory, then we will see a sharp decline in their population. Finding Nemo’s central message is conservation, yet it still prompted a 40 percent rise in sales of Clownfish for pets or decoration. This increase is alarming because even though Clownfish can be bred in captivity very easily, they are still often pulled from the ocean instead. The transition from ocean to captivity is very hard on reef fish like Clownfishes and Blue Tang fishes, often costing them their lives. Now that Disney knows the effect Finding Nemo had on Clownfish, they should prepare for the effect Finding Dory will have on Blue Tang by doing their part to warn folks who see the movie. With the new film Finding Dory coming out, researchers are seriously panicking. That’s because Dory, voiced by Ellen DeGenerous, is a Blue Tang Fish and that species has never been successfully bred in captivity. So each and every “Dory” Blue Tang Fish that is adopted will have been plucked from its home in the ocean. If folks purchase Blue Tang at the same rate as they did Clownfish after Nemo, the Blue Tang population will become extremely threatened. Even worse, researchers would have no way to repair the loss with captive breeding. Individual viewers may not know that Blue Tang can’t be bred in captivity. But Disney does, so they should educate viewers to protect the fish. Putting a simple PSA at the beginning of Finding Dory would significantly decrease the number of people who decide to adopt a Blue Tang fish. The film premiers on June 17; we have less than a month to convince Disney that they must educate consumers on the effect of adopting their own Dory. Add your name to this petition to tell Disney you want to see a warning at the beginning of Finding Dory discouraging folks from buying Blue Tang. ||||| A Care2 petition is asking Disney to run a PSA before screening 'Finding Dory' to ensure the safety of the blue tang. Dory is an ultra lovable Pixar character, which could prove to be a problem for the fish. A Care2 petition is asking Disney to take special precautions to ensure the safety of the blue tang, Dory's species of fish, leading up to and following the release of Pixar's Finding Dory. The petition is asking that Disney add a public service announcement to play before screenings of the latest Pixar film, which is set to hit theaters June 17, that will outline the importance of protecting the blue tang. Following the release of 2003's Finding Nemo, sales of clownfish (the species of Nemo and dad Marlin) skyrocketed. According to the Saving Nemo Conservation Fund, over 1 million clownfish are taken from reefs and sold for home aquariums each year, causing clownfish to go extinct in areas like the Philippines and parts of Thailand. “Now that Disney knows the effect Finding Nemo had on clownfish, they should prepare for the effect Finding Dory will have on blue tang by doing their part to warn folks who see the movie,” writes Care2 petition author Kelsey Bourgeois. "I love these films, but it is such a shame that harm can come to real animals because of them." The petition has already garnered over 27,000 signatures of its 30,000 goal. ||||| “Finding Nemo” was a huge box office success, but the clown fish population took a serious hit in the process because fans raced to pet stores to get their own pet Nemo. As “Finding Dory” is heading into theatres, a Care2Petition is requesting Disney to run a PSA before the movie, stressing the importance of protecting the Blue Tang fish. The petition has reached 27,000 of the 30,000 signatures goal. Care2Petition creator Kelsey Bourgeois told FOX411the Blue Tang fish is at risk due to the upcoming film. “When I saw a recent article about how the movie (‘Finding Nemo’) had adversely affected the Clownfish population, despite its main moral theme, I was dismayed,” she said. “Then I learned that with 'Finding Dory' the risk is even greater because Blue Tang Fish can't be bred in captivity, I was super worried.” After “Finding Nemo” in 2003, the sales of the clownfish skyrocketed. The Saving Nemo Conservation Fund proclaims on its website that over 1 million clownfish are taken from reefs and brought to aquarium’s each year, which adversely affects the population. Bourgeois said she believes Disney doesn't mean to be harming the fish population. “I really think Disney would not intend for their films to harm the actual animals their characters are based off and adding a PSA at the beginning of the movie would be such an easy way to help prevent that,” she explained. “It also seems like stating that would encourage more people to buy merchandise based on the fish, which would be great for Disney.” In her petition, she notes that “Finding Dory” has researchers panicking. “With the new film 'Finding Dory' coming out, researchers are seriously panicking,” she wrote. “So each and every 'Dory' Blue Tang Fish that is adopted will have been plucked from its home in the ocean. Individual viewers may not know that Blue Tang can’t be bred in captivity. But Disney does, so they should educate viewers to protect the fish.” “Finding Dory” stars Ellen DeGeneres, Ed O’Neill, Diane Keaton and Eugene Levy hits theaters June 17. Disney and Pixar did not return FOX411’s request for comment. ||||| Finding Dory: Film release sparks concern for impact on dwindling global clownfish population Updated Australian researchers are warning people not to take the "wrong message" from the sequel to Finding Nemo. Key points: Decline populations of tropical fish featured in the film linked to popularity as pets The blue tang cannot be bred in captivity Concerns raised about use of cyanide in capturing the fish from ocean Flinders University and the University of Queensland experts say studies conducted since the 2003 release have found clownfish populations declined on coral reefs after popularity in keeping the tropical fish as household pets soared. "The film had a very strong fish conservation message, but instead people decided, because Marlin and Nemo were such charismatic characters, that they wanted a clownfish as a pet," Flinders University associate Professor Karen Burke da Silva said. Some studies have looked at the declining rates of clownfish and other ornamental fish on coral reefs since the release of the animated film about clownfish Marlin, who goes on a search with blue tang Dory to find his son, Nemo, after he was abducted by a scuba diver and kept in an aquarium. "A number of studies in America looked at the huge increase in the demand for clownfish, according to pet shop figures, exports, et cetera," she said. "In one year alone, 2012, over 400,000 clownfish were imported to America. It was the fifth most imported species to America." Professor Burke da Silva is one of the co-founders of the Saving Nemo Conservation Fund, which aims to provide education, awareness and captive breeding programs to protect marine ornamental species that are often captured on reefs for sale in pet shops. She said the marine fish aquarium trade has been a major cause of the decline in coral reef fish numbers, because while clownfish are quite easy to breed in captivity, for a lot of ornamental fish it is not so easy. "About 90-95 per cent of marine fish found in aquarium shops come from the wild," she said. "The blue tang fish, for example, cannot be bred in captivity. This is because the blue tang fish release their eggs and sperm into the sea and this cannot be mimicked in a lab." People shocked to discover ornamental fish not bred in captivity Professor Burke da Silva said that from what she had read of the new film, she believed Finding Dory also has a strong conservation message. "What we hope is that people take that message home. Fish in the wild are going through enough problems, due to global warming and coral bleaching, so the worst thing we can do is add to that by taking huge numbers of them from the wild," she said. There was also a lack of understanding about what kind of fish are being taken from the wild and what fish are bred in captivity, Professor Burke da Silva said. "From our own surveys we've found that people who buy marine fish don't know they are taken from the wild," she said. "Freshwater fish are bred in captivity but ornamental fish — such as clownfish and blue tang fish — are not bred in captivity. "When we told them this, most people were shocked to discover that they weren't bred in captivity." She said the team wanted to create more awareness and to brand ornamental fish as not captive bred, "so then people are informed when they go into a pet shop to buy a fish". Professor Burke da Silva said there were concerns about the welfare of the animals collected from places like Sri Lanka and Philippines, huge exporters of ornamental fish to places like US. "They sometimes use cyanide poisoning to collect fish. It is used as a kind of anaesthetic to knock them out so they can be easily collected in a short amount of time," she said. However, Professor Burke da Silva said the lengthy process of collecting the fish and exporting them can have a huge effect on mortality rates. She said she had once read up to 90 per cent "die before they make it into someone's living room". "What we mostly want to achieve is an awareness about where the fish come from and the fact that ornamental fish are being taken from the wild and 100 per cent of blue tang fish are caught in the wild," she said. Topics: fish, animal-science, film-movies, australia, asia First posted

– Disney's upcoming film Finding Dory will likely be a hit with kids around the world, and that's got fish-lovers worried. “Now that Disney knows the effect Finding Nemo had on clownfish, they should prepare for the effect Finding Dory will have on blue tang by doing their part to warn folks who see the movie," states an online petition that's gathered more than 60,000 signatures so far. The petition is asking Disney to run a PSA before screenings of Finding Dory. The Saving Nemo Conservation Fund says more than 1 million clownfish are taken from reefs every year and sold as pets thanks to the popularity of Finding Nemo, according to the Hollywood Reporter. That's led to the extinction of clownfish in certain areas. The problem could be even worse for blue tang, which can't be bred in captivity. That means 100% of blue tang bought by and for Dory-loving children will come from the wild, and conservationists have no way of replacing them. “I really think Disney would not intend for their films to harm the actual animals their characters are based off, and adding a PSA at the beginning of the movie would be such an easy way to help prevent that,” Kelsey Bourgeois, who created the online petition, tells Fox News. Karen Burke da Silva, cofounder of the Saving Nemo Conservation Fund, tells ABC most people are unaware that the majority of the marine fish they're buying as pets weren't raised in captivity. A PSA before Finding Dory, which opens June 17, could change that. (Vandals may have killed one of the world's rarest fishes.)

there is compelling evidence that the universe is currently undergoing a phase of accelerated expansion @xcite . this indicates some new physics at cosmological scales ( dark energy " ) @xcite that can give rise to repulsive gravity resulting the universe to accelerate . the cosmological constant with @xmath11 is the simplest example of repulsive gravity and is consistent with the majority of cosmological observations . but the observational data at present is also consistent with dark energy behavior which is strictly not constant but evolves slowly throughout the cosmological history . moreover the cosmological constant comes with its own baggage of problems like cosmic coincidence problem which can be avoided using dynamical dark energy . scalar fields are the most widely used dynamical dark energy models where late time acceleration can be obtained by adjusting the slope of the scalar field potential around suitable epoch @xcite . but the cosmological evolution of these models is severely constrained by very accurate cosmological observations . from the measurements of temperature anisotropy in the cosmic microwave background ( cmb ) radiation , the distance to last scattering is very well determined . this restricts the equation of state for the scalar field to be very close to @xmath12 at present . the type - ia supernovae observations as well as baryon acoustic oscillation ( bao ) measurement in the large scale structures also give similar constraint on the scalar field equation of state . on the other hand cmb measurements also restricts the scalar field contribution to the total energy density of the universe during recombination to be less than @xmath13 . all these constraints disfavor @xcite the original tracker " kind of quintessence model@xcite where the scalar field initially has a fast roll phase before settling to the cosmological constant behavior at present . just recently , analysis of the spectrum from a distant quasar finds no evidence of deviation in molecular lines produced around 12 billion years ago . this confirms no change in the mass ratio of the proton to the electron . the results also indicate that a dark energy scalar field if it exists has not evolved appreciably over @xmath14 the age of the universe @xcite , thereby putting doubt on the tracker kind of models as a possible candidate for dark energy . the other scalar field behavior that is consistent with the present observational data is the thawing " one @xcite . currently there are many types of scalar field models that can give rise to thawing behavior . examples are quintessence @xcite , tachyons @xcite as well as galileon @xcite models . in all these thawing models , the thawing nature does not depend crucially on the form of the potential . once the initial conditions are chosen in such way that the scalar field starts in a nearly frozen state with @xmath15 , the thawing behavior is ensured . fine tuning this initial condition is an issue in all thawing type of models . in a recent investigation , attempt has been made to relate this initial condition to inflationary dynamics @xcite . given the fact that thawing models are observationally promising as a possible candidate for dynamical dark energy models , we need to have a combined setup to investigate the cosmological evolution for different thawing scalar field models . in this work , we present such a setup in a python environment . we name this setup as scalpy " which solves the autonomous system with a given scalar field model by providing suitable initial conditions and calculates the observables like normalized hubble parameter , angular diameter distance , luminosity distance , growth function , growth rate , linear matter power spectrum etc . we consider two simple potentials , the power - law and exponential for all the different versions of the scalar fields as these are the two most widely used potentials for dark energy in the literature . but one can easily incorporate the other potentials in this package . we also combine the package with the publicly available mcmc sampler emcee " @xcite to do the statistical analysis of different scalar fields with observational data . given the promise of thawing scalar field models as possible candidate for the dark energy , there are several investigations related to the thawing model for different types of scalar field . all these works are related to individual scalar field models and there are not many attempts to study the different thawing scalar field model in a combined approach . this is the first such combined approach in python environment . this paper is structured as follows . in the section ii , we describe the autonomous system of equations for different scalar field models and also the method to fix the initial conditions to solve these systems ; in section iii , we describe different cosmological observable that scalpy calculates for different scalar field models ; in section iv , we describe different data sets that are used to put observational constraints on different models and the results of the data analysis ; finally we summarizes our results in the conclusion section . in the appendix part of the manuscript , we briefly describe how to install and to use scalpy . in the present investigation , we confine ourselves to flat frw universe with scale factor @xmath16 and given by the line element @xmath17 where @xmath18 . the scale factor at present is set to be @xmath19 . in the late time evolution of the universe , the dominant contribution to the energy budget of the universe is from the non - relativistic matter ( baryons+dark matter ) and from the dark energy . in the present paper we are interested in studying various forms of scalar field models as the dark energy component in the universe .. in following subsection we will look at quintessence , tachyon and galileon fields and see how we make autonomous systems in these frameworks . we consider a minimally coupled scalar field and lagrangian for such a field is given by @xmath20 where @xmath21 is the given potential . one can calculate the energy momentum tensor and by considering perfect fluid , the energy density and pressure of quintessence field is given by @xmath22 the equation of motion for scalar field obtained by variation of action with respect to field @xmath23 is @xmath24 where the subscript @xmath23 denotes the derivative with respect to field @xmath23 . the hubble equation is given by @xmath25 where @xmath26 is the total density of matter and scalar field . we define the variables @xmath27 , @xmath28 , and @xmath29 as @xcite @xmath30 here the prime denote the derivative with respect to the e - folding @xmath31 (= @xmath32 ) i.e. @xmath33 and subscript ` @xmath23 ' denote the derivative with respect to field @xmath23 . in terms of these variables @xmath34 where @xmath35 is the density parameter for scalar field and @xmath36 is the equation of state . we can construct an autonomous system using variables @xmath27 , @xmath28 and @xmath29 @xmath37\label{quint1}\\ y^\prime & = & -\lambda\sqrt{\frac{3}{2}}xy + \frac{3}{2}y[1+x^2-y^2 ] \label{quint2}\\ \lambda^\prime & = & - \sqrt{6 } \lambda^2(\gamma - 1 ) x. \label{quint3}\end{aligned}\ ] ] in terms of @xmath38 , @xmath39 and @xmath29 , the above equations becomes @xcite , @xmath40 cosmological dynamics for tachyonic field can be obtained by the dirac - born - infeld ( dbi ) type action @xcite @xmath41 in natural units , the dimension of the tachyon field is @xmath42^{-1}$ ] . the energy density , pressure and equation of state of the tachyon field is given by @xmath43 the equation of motion for tachyon field is @xmath44 again we define following dimensionless variables @xmath45 in terms of these variables , equation of state @xmath46 and density parameter @xmath35 for the tachyon field is @xmath47 we construct the autonomous system for tachyon field @xcite @xmath48 the large scale modification of gravity which involves an effective scalar field @xmath49 can explain late time acceleration of the universe . this field @xmath49 is called galileon " and its lagrangian respects the shift symmetry in the minkowski background satisfying @xmath50 and @xmath51 where @xmath52 and @xmath53 are constants @xcite . the action for galileon field up to third order is @xcite @xmath54 + \mathcal{s}_m , \label{1.1}\ ] ] where @xmath55 is reduced planck mass . @xmath56 is the dimensionless constant and setting it equal to zero givers the standard quintessence action . @xmath57 is the constant with mass dimension and it can be fixed to @xmath58 by redefining @xmath56 . again by defining following dimensionless variables , @xmath59 we construct the autonomous system @xcite @xmath60 for @xmath61 we recover the autonomous system for the standard quintessence - . the density parameter @xmath62 and equation of state for the @xmath49 field is given by : @xmath63 to solve a cosmological dynamical system , we have to choose a point in time where we set the appropriate initial conditions and then let the system evolve till present day . we give initial conditions at around decoupling ( @xmath64 ) . in case of quintessence and tachyons , we solve the autonomous system of equations in terms of @xmath39 , @xmath38 and @xmath29 given by equations - and -for quintessence and tachyon respectively . we have to provide initial conditions for @xmath65 , @xmath66 and @xmath67 where `` i '' represents the initial value . as we are considering the thawing class of models , the scalar field is initially nearly frozen due to large hubble friction and hence we choose @xmath65 to be close to zero . throughout rest of the paper , we fix @xmath68 . @xmath67 is the initial slope of the potential and @xmath69 gives an exact cosmological constant behavior . so values for @xmath67 different from zero , gives the deviation from cosmological constant . in our subsequent calculations , we choose @xmath67 to be a parameter of the model . as the contribution of dark energy to be negligible in the early time , @xmath66 should be close to zero initially . but it has to be fixed initially in such a way that for a given @xmath65 and @xmath67 , the system evolves to present day with the appropriate value of @xmath70 where `` 0 '' stands for present day value . we check that @xmath66 around @xmath71 gives suitable values for @xmath70 . so in our calculations , we choose @xmath66 to be the second parameter and varies it between @xmath72 to @xmath73 . for galileon field , we solve autonomous systems in terms of variables @xmath27 , @xmath28 , @xmath74 and @xmath29 given by the equations - and hence we have to provide four initial conditions for @xmath75 , @xmath76 , @xmath77 and @xmath78 respectively . as here also , we consider the thawing behavior only , the galileon field is initially nearly frozen and hence @xmath79 . we set @xmath80 in our calculations . for @xmath66 to be the same as in quintessence and tachyon , @xmath81 and @xmath82 are now related by equation . so we vary @xmath81 and @xmath66 as two parameters and @xmath82 is fixed subsequently by equation . we also consider @xmath67 as our third parameter as it gives the deviation from cosmological constant . so in galileon models , we have three parameters , @xmath83 and @xmath67 . for power law and exponential potential , @xmath84 is a constant while for other potentials , @xmath84 evolve as a function of @xmath29 in equations , and . following david hogg @xcite we define observable quantities such as hubble distance , luminosity distance , angular diameter distance and lookback time . the hubble distance is defined as @xmath85 where c is the speed of light and @xmath86 is the hubble constant . since we have assumed a flat flrw metric , the line of sight comoving distance is defined as @xmath87 where @xmath88 is normalized hubble parameter . the angular diameter distance @xmath89 and luminosity distance @xmath90 are related to comoving distance as @xmath91 where @xmath92 is transverse comoving distance which is equal to @xmath93 for the flat universe . we also define lookback time @xmath94 to an object as the difference between age of the universe and the time when the light was emitted from that object : @xmath95 the age of the universe is given by , @xmath96 we also define om diagnostic @xcite in our package : @xmath97 the time delay distance used in gravitational lensing cosmography is also included in the package . it is defined as @xcite @xmath98 where @xmath99 is the angular diameter distance to the deflector or lens at redshift @xmath100 and @xmath101 is the angular diameter distance to the source . @xmath102 is the angular diameter distance between source and deflector . in figure 1 we plotted equation of state , @xmath1 as a function of redshift for each type of scalar field ( quintessence , tachyon and galileon ) with power law potential ( @xmath103 ) and for exponential potential . the initial conditions we choose for quintessence and tachyon fields are ( @xmath104 ) @xmath105 ( @xmath106 ) and for galileon field we choose ( @xmath107 ) @xmath105 ( @xmath108 ) . the value of @xmath109 for all three types of field is taken to be @xmath110 . + we consider perturbation in matter part only and scalar field is homogeneous . we are interested in structure formation to scale much smaller than the hubble radius so the newtonian approximation is valid . the density contrast of matter field @xmath111 follows the equation at sub - horizon approximation @xmath112 taking fourier transform of above equation and defining the linear growth function @xmath113 and the linear growth rate @xmath114 as @xmath115 we calculate the linear matter power spectrum defined as @xmath116 here @xmath117 is the normalization constant , @xmath118 is spectral index for the primordial density fluctuations generated through inflation , @xmath119 is growth function normalized such as it is equal to unity at @xmath120 i.e. @xmath121 and @xmath122 is the transfer function as prescribed by eisenstein and hu @xcite for a mixture of cdm and baryons : @xmath123 where @xmath124 is density parameter for cdm and @xmath125 . the form for @xmath126 and @xmath127 are given by eisenstein and hu @xcite . an important quantity @xmath128 is defined as the fluctuation of mass within the boxes of @xmath129 mpc when we move from place to place in present day universe . : @xmath130 where the window function @xmath131 is defined as @xmath132 and for @xmath10 , one puts @xmath133 mpc . using definition of @xmath128 and window function , we fix the normalization constant @xmath117 as @xcite @xmath134 where we take @xmath135 mpc . fig 2 shows the behavior of @xmath136 as a function of z for quintessence , tachyons and galileon fields with exponential as well as power law potential . we used the same initial conditions as used for plotting equation of state in figure 1 . we used our scalpy package and mcmc hammer ` emcee ' @xcite to constrained model parameters of quintessence , tachyon and galileon fields as well as @xmath1cdm , @xmath137cdm and @xmath138 models(see appendix ) . we used following data sets for our analysis : * 31 binned distance modules fitted to jla sample given by by m. betoule et al . @xcite * combined bao / cmb constraints on the angular scales of the bao oscillations in the matter power spectrum measured by sdss survey , 6df galaxy survey and the wiggle - z survey . we used covariance matrix for this provided by giostri et al @xcite . * we also used measurement of shift parameter of cmb as given in shafer et al @xcite . * measurements for @xmath139 by various galaxy surveys like 2df , sdss , 6df , boss and wiggle - z . a compilation of different measurements for @xmath139 has been provided by basilakos et al.@xcite the results for data analysis for quintessence , tachyon field and galileon field with linear potential are shown in figure ( 3 ) . we used @xmath140 in our analysis . we show the 1@xmath141 , 2@xmath141 and 3@xmath141 contours in @xmath142 plane . the @xmath0cdm behavior ( @xmath143 ) is allowed for all these types of scalar fields within 1@xmath141 region with considerable range of @xmath144 values . one can also see that the constraints on present day equation of state @xmath145 and density parameter for matter @xmath144 are same for all three type of scalar fields with linear potential . this result also holds for other power law potentials . in figure ( 4 ) and ( 5 ) we show the constraints on model parameters for @xmath137cdm and @xmath1cdm models respectively . the concordance @xmath0cdm model is within @xmath146 error bar when we combine all the four data sets used . the constraints on the model parameters of gcg model is shown in figure ( 6 ) . the parameter @xmath147 is related to present day equation of state @xmath145 as @xmath148 . we see that @xmath149 is again allowed within @xmath146 region for gcg as well . [ cols="^,^ " , ] to install the code , one can simply use _ pip _ or download the full source code and run ` setup.py ' file . on a linux system where pip is installed , scalpy can be installed asuser@computer > sudo pip install scalpy to install it from source code which is downloadable as .zip file from github repository , simply download the source fromhttps://github.com / sum33it / scalpy after extracting the file , move to the folder ` scalpy - master ' and run ` setup.py ' fileuser@computer > unzip scalpy-master.zip user@computer > cd scalpy - master user@computer > python setup.py install the package consists of following main modules linked with each other : 1)*scalar.py * this module solves the dynamical system for scalar fields such as minimally coupled quintessence , tachyon and galileon . we have included two types of potential for each scalar field : power law @xmath150 and exponential @xmath151 where @xmath152,@xmath56 and @xmath153 are real constants + 2 ) * fluids.py * this gives different observables for standard cosmological models such as @xmath154 , @xmath155 , @xmath156 and @xmath138 in this file also , different observables such as luminosity distance , hubble parameter , angular diameter distance , growth rate , growth function , power spectrum are defined + 3 ) * solver.py * for a given values of @xmath145 and @xmath70 , this module solves for the initial conditions needed at decoupling for scalar field models . + 4 ) * transfer_func.py * in this module , we have defined transfer functions given by eisenstein and hu as well as by bbks . + detailed online documentation with examples can be found at following url : + http://ctp-jamia.res.in/download/scalpy 99 s. perlmutter et al , apj , * 517 * , 565 ( 1999 ) . a. riess et al , astron . j. , * 116 * , 1009 ( 1998 ) . p. a. r. ade et al , arxiv:1502.01589 . g. f. hinshaw et al , apjs , * 208 * , 19h ( 2013 ) . d. j. eisenstein et al , astron . j. , * 142 * , 72 ( 2011 ) . a. g. sanchez et al , mnras , * 425 * , 415s ( 2012 ) . d. parkinson et al , phys . d , * 860 * , 103518 ( 2012 ) . v. sahni and a. a. starobinsky , int . j. mod . d * 9 * , 373 ( 2000 ) ; s. m. carroll , living rev . * 4 * , 1 ( 2001 ) ; p. j. e. peebles and b. ratra , rev . phys . * 75 * , 559 ( 2003 ) . e. j. copeland , m. sami and s. tsujikawa , int . d * 15 * , 1753 ( 2006 ) ; p. j. e. peebles and b. ratra , astrophys . j. , * 325 * , l17 ( 1988 ) ; c. wetterich , nucl . phys . b * 302 * , 668 ( 1988 ) ; m. s. turner and m. white , phys . d * 56 * , 4439 ( 1997 ) ; r. r. caldwell , r. dave and p. j. steinhardt , phys . lett . * 80 * , 1582 ( 1998 ) ; i. zlatev , l. m. wang and p. j. steinhardt , phys . rev.lett . * 82 * , 896 ( 1999 ) . e. v. linder , arxiv:1501.01634 [ astro-ph.co ] . r. r. caldwell and e. v. linder , phys . lett . * 95 * , 141301 ( 2005 ) . a. nicolis , r. rattazzi and e. trincherini , phys . d , * 79 * , 064036 ( 2009 ) ; c. burrage , c. de rham , l. heisenberg , jcap , * 1105 * , 025 ( 2011);a . ali , r. gannouji and m. sami , phys . rev . d , * 82 * , 103015 ( 2010 ) ; r. gannouji and m. sami , phys . d , * 82 * , 024011 ( 2010 ) . d. w. hogg , astro - ph/9905116 . v. sahni , a. shafieloo and a. a. starobinsky , phys . d * 78 * , 103502 ( 2008 ) [ arxiv:0807.3548 [ astro - ph ] ] . s. h. suyu , m. w. auger , s. hilbert , p. j. marshall , m. tewes , t. treu , c. d. fassnacht and l. v. e. koopmans _ et al . _ , astrophys . j. * 766 * , 70 ( 2013 ) [ arxiv:1208.6010 [ astro-ph.co ] ] . c. knobel , arxiv:1208.5931 [ astro-ph.co ] . d. j. eisenstein and w. hu , astrphys . j. , * 496 * , 605 ( 1998 ) . m. betoule _ et al . _ [ sdss collaboration ] , astron . astrophys . 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we present a python package `` scalpy '' for studying the late time scalar field cosmology for a wide variety of scalar field models , namely the quintessence , tachyon and galileon model . the package solves the autonomous system of equations for power law and exponential potential . but it can be easily generalized to add more complicated potential . for completeness , we also include the standard parameterization for dark energy models , e.g. the @xmath0cdm , @xmath1cdm , @xmath2cdm as well as the gcg parameterization . the package also solves the linear growth equation for matter perturbations on sub - horizon scales . all the important observables related to background universe as well as to the perturbed universe , e.g. luminosity distance ( @xmath3 ) , angular diameter distance ( @xmath4 ) , normalized hubble parameter ( @xmath5 ) , lookback time ( @xmath6 ) , equation of state for the dark energy ( @xmath7 ) , growth rate ( @xmath8 ) , linear matter power spectra ( @xmath9 ) , and its normalization @xmath10 can be obtained from this package . the code is further integrated with the publicly available mcmc hammer emcee " to constrain the different models using the presently available observational data . the code is available online at https://github.com/sum33it/scalpy

in order to demonstrate the hierarchy of various contributions to the observable ( [ de ] ) in @xmath7@xmath844 mass region we have performed additional calculations using the skyrme edf ( [ hte])-([hto ] ) . the results are depicted in fig . the upper part of the figure shows relative changes @xmath86 in the energy differences @xmath48 caused by @xmath875% changes in @xmath88 ( surface ) , @xmath89 ( effective mass ) , and @xmath90 ( spin - orbit ) coupling constants with respect to their original values . the lower part illustrates relative changes in the total binding energy @xmath91_{i_{max}})$ ] of the aligned state @xmath30_{i_{max}}$ ] caused by these variations in the coupling constants . this figure clearly shows that the hierarchy established in ref . @xcite on the basis of the schematic nilsson model is correct . the leading contribution to @xmath86 is indeed the spin - orbit term . the contribution coming from the effective mass term is circa 2.5 times smaller and is clearly non - perturbative as it impacts binding energies by @xmath810mev . in the same spirit we have also investigated the influence of @xmath871% variations in the bulk energy parameter @xmath92 on both @xmath48 and @xmath79_{i_{max}})$ ] . these tiny variations in @xmath92 impact binding energies by @xmath815mev and , at the same time , affect @xmath48 only by @xmath8@xmath8730kev .

the problem of the effective mass scaling in the single particle spectra calculated within the skyrme energy density functional ( edf ) method is studied . it is demonstrated that for specific pairs of orbitals the commonly anticipated isoscalar effective mass ( @xmath0 ) scaling of the single - particle level splittings is almost canceled by an implicit @xmath0-scaling due to other parameters in the skyrme edf . this holds in particular for an indirect @xmath0-scaling of the two - body spin - orbit strength making the theory essentially unpredictable with respect to single particle energies . it is argued that this unphysical property of the skyrme edf is a mere consequence of the strategies and datasets used to fit these functionals . the inclusion of certain single - particle spin - orbit splittings to fit the two - body spin - orbit and the tensor interaction strengths reinstates the conventional @xmath0-scaling and improves the performance of the skyrme edf . fundamental excitations in atomic nuclei are often characterized in terms of single particle and collective excitations . a successful nuclear theory is required to account for both kinds at a qualitative _ and _ quantitative level . the effective nuclear energy density functionals ( edf ) irrespectively of their variants including local ( skyrme ) , non - local ( gogny ) or relativistic mean - field ( rmf ) have developed toward high accuracy in recent years , both with respect to bulk properties and predictions of single particle properties@xcite . still , on a quantitative level , properties of single particle states are often better described by means of simple potentials like the nilsson or woods - saxon . this is highly unsatisfactory , since one expects a full fledged edf to describe nuclear properties at a level of accuracy superior to that of simple potentials . the uncertainty of present edf with respect to nuclear properties has its roots in the fitting procedure of its parameters as well as the non local terms in the interaction . the edf s are conventionally adjusted to reproduce ground - state bulk nuclear properties , see e.g. ref.@xcite . the datasets used to fit their parameters are dominated by nuclear data extrapolated to the thermodynamic limit and by nuclear binding energies in selected doubly magic nuclei . these fitting procedures are known to impair basic buildings blocks of these theoretical models , in particular single - particle ( s.p . ) energies . the physical relevance of s.p . energies provided by self - consistent mean - field ( mf ) approaches based on the edfs or effective interactions is continuously contested . the debate has its roots in the non - locality of these approaches resulting in a low isoscalar effective mass @xmath1 @xcite which in turn scales the s.p . level density @xmath2 in the vicinity of the fermi energy @xmath3 according to the simple rule : @xmath4 . this simple rule applies strictly to homogeneous nuclear matter only . in finite nuclei the effective mass depends on @xmath5 and the @xmath4 scaling should be considered as an idealization . the effective mass scaling leads to a dichotomous and in fact highly uncomfortable situation . indeed , in spite of the fact that it makes all applications of the self - consistent mf methods to low - lying nuclear excitations rather dubious such calculations are carried out routinely and published often without even a word of comment or justification . the aim of this letter is to demonstrate that the problem of the effective mass scaling within the _ effective theory _ is far more intricate than anticipated . it turns out that the effective mass dependence of the calculated single particle spectrum can depend on the structure of the edf , on the strategies employed when adjusting the interactions and upon the choice of dataset used in these fits . we will demonstrate first that conventional functionals which are , as discussed above , fitted almost ultimately to bulk nuclear properties have an built in _ implicit _ effective mass scaling of certain coupling constants including in particular the two - body spin - orbit strength . for many modern parameterizations of the skyrme force this mechanism is strong enough to cancel the effect of the s.p . level density scaling caused by the low effective mass with respect to the calculated specific particle - hole excitation . for example the @xmath6 splitting in @xmath7@xmath844 mass region @xcite calculated using forces having effective masses ranging from @xmath9 yield similar result in spite of the expected effective mass dependence . in the next step we will show that this counterintuitive result is a mere consequence of the fitting strategies and that by shifting the attention from bulk to single - particle properties in the process of fitting of the nuclear edf parameters one can both remove the artificial @xmath0-scaling from the two - body spin - orbit strength and reinstate the conventional and anticipated @xmath0-scaling in the calculated @xmath10 excitation energies . all the calculations performed in this letter are based on skyrme - force inspired local edf ( sedf ) of the form : @xmath11 where @xmath12 @xmath13 it depends on isoscalar @xmath14 and isovector @xmath15 time - even @xmath16 , @xmath17 , and @xmath18 , and time - odd @xmath19 , @xmath20 , and @xmath21 , local densities for which we follow the convention introduced in ref . @xcite , see also refs . @xcite and references cited therein . all numerical results presented below were obtained using the hfodd code of ref . @xcite and the following set of the skyrme forces : sly4@xmath22 , sly5@xmath22 @xcite , siii@xmath22 @xcite , skm@xmath23 @xcite , skxc@xmath22 @xcite , msk1@xmath22 @xcite , skp@xmath22 @xcite , and sko@xmath22 @xcite . the subscript @xmath24 indicates here that the original time - odd functional coupling constants @xmath25 , and @xmath26 were replaced in the calculations by the coupling constants reproducing the empirical landau parameters in accordance to the prescription given in refs . @xcite . in spite of the fact that we will concentrate here on the _ implicit _ @xmath0-scaling of certain functional coupling constants it should be mentioned that some of the sedf parameters do scale or depend upon @xmath0 explicitly . the _ explicit _ effective mass scaling is well established for the ( _ i _ ) @xmath27 and @xmath26 functional parameters through the fit to the empirical landau parameters @xcite and ( _ ii _ ) for the isovectorial coupling constants @xmath28 and @xmath29 through the fit to the empirical symmetry energy strength @xcite . an almost ideal playground to investigate the impact of fitting procedures on the performance of the effective forces with respect to the @xmath10 related observables is offered by fully stretched @xmath30_{i_{max}}$ ] and @xmath31_{i_{max}}$ ] states in @xmath32@xmath33@xmath34 nuclei in the @xmath7@xmath844 mass region where @xmath35 denotes number of valence particles in the @xmath36 sub - shell @xcite . in a series of publications @xcite we have demonstrated that these states represent one of the best examples of almost unperturbed single - particle motion and that the energy difference : @xmath37_{i_{max } } ) - e([d_{3/2}^{-1 } f_{7/2}^{n+1}]_{i_{max}})\ ] ] constitutes a very reliable probe of various properties of the edf . in particular , it can be used to readjust the time - odd components @xmath27 , @xmath38 and @xmath26 to comply with the empirical landau parameters leading to an unification of the theoretical predictions for @xmath39 for various popular skyrme parameterizations @xcite . defined in eq . ( ) . calculations have been done using different popular parameterizations ( see legend ) of the skyrme functionals with spin - dependent coupling constant readjusted to reproduce the empirical landau parameters in accordance to refs . . , scaledwidth=45.0% ] the calculated values of @xmath39 , see fig . [ ttf1 ] , show a striking and completely unexpected feature . the mean deviation of the theoretical predictions with respect to the empirical values is very similar for such forces like sly4 , sly5 ( @xmath40 ) , siii ( @xmath41 ) , sko ( @xmath42 ) and skxc ( @xmath43 ) . in spite of the fact the the effective masses differ by as much as 30% , we obtain for these parameterizations @xmath44kev with a rms deviation of @xmath45kev . this result is indeed extremely puzzling since the anticipated influence of a naive @xmath0-scaling with respect to a @xmath10 excitation energy of order of @xmath46mev is , for the analyzed set of forces , estimated to be more than one order of magnitude larger , exceeding @xmath47mev . unexpectedly , the observable @xmath48 appears to be very robust . indeed , the structural purity of the terminating states in the @xmath7@xmath844 mass region reveal a firmly established hierarchy of different physical contributions to that quantity and in turn allows to identify the physical source of the _ cancellation _ of the @xmath0-scaling in the functional . in ref . @xcite we established the hierarchy of three different components , the energy scale @xmath49 , the strength of the spin - orbit ( so ) and the @xmath50 ( surface ) term using the nilsson hamiltonian . this schematic model clearly indicates the dominant influence of the mean so potential on @xmath48 . this observation is neatly correlated with self - consistent shf models , see the appendix below where we give a numerical proof for the case of the skyrme functionals . indeed , the isoscalar strength of the skyrme one - body so potential emerging from the two - body so interaction @xmath51 appears to be almost perfectly linearly correlated with the effective mass @xmath0 parameter as shown in fig . [ ttf2 ] . large values of @xmath52 which characterize low@xmath53 forces tend to reduce the @xmath54-@xmath36 splitting thus compensating the @xmath0-scaling effect on the @xmath32=@xmath34=20 magic gap . as shown in ref . @xcite a similar cancellation takes place for the @xmath55-@xmath56 and @xmath57-@xmath58 splittings in the @xmath7=16 and @xmath7=80 mass regions , respectively . for these splittings the schematic nilsson model indicates an indisputable dominance of the so term over the surface ( or , more precisely , the @xmath59 ) contribution . on the other hand , for the @xmath55-@xmath58 splitting in the @xmath7=80 mass region , the so and the @xmath60 contributions are predicted to be similar . for this particular case also the self - consistent shf calculations provide results which are qualitatively different than in the previous cases indicating a more complex dependence . . stars mark the skyrme forces having non - zero tensor terms . , scaledwidth=45.0% ] single - particle states versus @xmath61 calculated using different skyrme forces . the lower part shows the @xmath62 spin - orbit splitting versus @xmath52 calculated using the same set of the skyrme forces . black ( open ) dots mark results obtained using standard ( 10% reduced ) strength of the two - body spin - orbit interaction , respectively . the figure clearly demonstrates the presence of two conflicting scalings within the skyrme model . see text for further details . , scaledwidth=45.0% ] the _ implicit _ mass scaling of the two - body skyrme spin - orbit strength has unexpected and serious consequences : within a single theoretical framework two conflicting scalings are present . indeed , particle - hole excitations associated with the spin - orbit partners such as @xmath63 scale directly with @xmath52 . at the same time the @xmath64 @xmath10 excitations scale according to the @xmath65 as shown in fig . [ ttf3 ] . at first glance this puzzling situation seem to have no satisfactory and unique solution within the conventional skyrme edf . although a reduction in @xmath52 ( see open symbols in fig . [ ttf3 ] ) clearly improves the agreement to the data it can hardly be accepted as a reasonable solution . indeed , the figure indicates that the empirical @xmath66 splitting ( experimental data are marked by thick horizontal lines in fig . [ ttf3 ] ) is reached first by reducing @xmath52 strength in parameterizations characterized by large-@xmath67 values . in contrast , agreement to the empirical @xmath68 splitting is obtained after reducing the @xmath52 strength in low-@xmath67 parameterizations . therefore , a conventional theory can not reproduce simultaneously both empirical values . to state it differently : the standard set of skyrme forces appear to be incomplete when confronted to experimental data . fig . [ ttf3 ] suggests that the simultaneous agreement for both @xmath68 and @xmath66 splittings calls for parameterizations having large @xmath67 and drastically reduced @xmath52 . drastic reduction of @xmath52 will spoil , however , the relatively good agreement for our high - spin observable @xmath48 , see fig . [ ttf1 ] . hence a compensation mechanism is required . this mechanism exist , it is not new @xcite and it is provided by a tensor component . however , until very recently , there has been little need to invoke the _ strong _ tensor interaction in edf s , see @xcite . in our recent contribution @xcite we have shown that the tensor interaction can be rather unambiguously fitted using the @xmath63 spin - orbit splittings in three key nuclei including : the isoscalar spin - saturated @xmath69ca nucleus , the isoscalar spin - unsaturated @xmath70ni nucleus , and the isovector spin - unsaturated @xmath71ca nucleus . unlike in the other studies cited above our work firmly revealed the need for a simultaneous drastic reduction of the two - body so strength . such a procedure definitely changes the philosophy behind conventional fitting strategies by shifting the attention from mass dominated gross features to procedures including carefully selected single - particle states which are used to adjust specific coupling constants in the functional . we are now in a position to verify the consistency of our new fitting strategy using high spin terminating states . we have therefore repeated the calculations for the energy differences @xmath48 of eq . ( [ de ] ) but using parameterizations siii@xmath72 , sko@xmath72 , sly4@xmath72 , skp@xmath72 , and skxc@xmath72 . subscript @xmath73 indicates that these parameterizations have : ( _ i _ ) time - odd spin - fields readjusted to empirical landau parameters and ( _ ii _ ) modified tensor and two - body so strengths . new values of the tensor and the two - body so functional coupling constants are collected in tab . [ fity ] . all other coupling constants of these parameterizations are kept to their original values . energy splittings given by eq . ( ) . upper part shows the results obtained using sly4@xmath72 , skp@xmath72 , siii@xmath72 , and sko@xmath72 parameterizations with modified spin fields and the two - body so and tensor strengths readjusted to the empirical @xmath62 splittings , see table . lower port shows the differences @xmath74 between the isoscalar effective mass scaled theoretical splitting @xmath75 and the experimental value . see text for further details.,scaledwidth=45.0% ] .spin - orbit @xmath76 and tensor isoscalar @xmath77 and isovector @xmath78 functional coupling constants adopted for different parameterizations . these modified parameterizations are subsequently used in the calculations presented in fig . [ ttf4 ] . [ cols="^,^,^,^,^ " , ] ( upper part ) and in the binding energy @xmath79_{i_{max}})$ ] ( lower part ) caused by 5% variations in @xmath80 ( surface ) , @xmath81 ( effective mass ) , and @xmath76 ( spin - orbit ) coupling constants in the skyrme functional.,scaledwidth=45.0% ] the results of our calculations are depicted in the upper part of fig . [ ttf4 ] . it is interesting to observe that all large-@xmath0 parameterizations including sko@xmath72 ( @xmath42 ) and skp@xmath72 ( @xmath43 ) are giving satisfactory agreement to the data . in the particular case of the skxc@xmath72 ( @xmath43 ) force ( not shown in the figure ) the mean deviation from the data equals to @xmath82kev only ! at the same time low-@xmath0 parameterizations including sly4@xmath72 ( @xmath40 ) and siii@xmath72 ( @xmath41 ) strongly overestimate the data . this result clearly follows the conventional wisdom related to the @xmath0-scaling of the s.p . level density . to visualize this even better we have rescaled the theoretical energy difference by the effective mass @xmath83 and have plotted the difference @xmath84 in the lower panel of fig . [ ttf4 ] . three out of four curves depicted in this figure follow closely each other and the experiment . the curve representing the sly4@xmath72 is slightly below the trend , indicating too small a reduction of the two - body so strength ( by 35% ) done in ref . @xcite . the quantity @xmath48 can therefore be used for further fine tuning of the so strength and indeed , a reduction of the so strength by 40% shifts the sly4 curve by 250kev up as expected . one has to remember however , that the entire effective mass scaling concept in finite nuclei is only an idealization . last but not least let us observe that all curves shown in fig . [ ttf4 ] do not reveal any clear isotopic and/or isotonic dependence , in contrast to the previous calculations presented in fig . [ ttf1 ] . this indicates a clear improvement of the isovector channel due to the presence of a strong isovector tensor component in the functional . in summary , we have investigated the impact of the fitting procedures and the datasets used to fit the skyrme energy density functionals with respect to their spectroscopic properties . we have demonstrated that the use of parameterizations fitted to reproduce bulk nuclear data in the thermodynamic limit and to binding energies of selected double - magic finite nuclei to analyze spectroscopic data may lead to rather poor results . this is due to an implicit internal @xmath0-scaling of , in particular , the two - body so strength which is a mere consequence of the fitting procedure . we have further demonstrated that conventional skyrme forces having the two - body so strength and tensor coupling constants fitted directly to the empirical s.p . @xmath85 so splittings behave according to the expected @xmath0-scaling law for particle - hole excitations . the present study seems to confirm the common expectation that effective interactions with large effective mass have a superior performance for calculations of spectroscopic data . it sends however a clear message that this conclusion is strongly dependent on the fitting process for effective forces . involving a larger set of single particle data , in particular selected high spin terminating states reveal the need for a considerable reduction of the conventional two - body spin - orbit term and at the same time the requirement for a strong tensor term introduced in ref . @xcite . this work was supported in part by the polish ministry of science and the swedish research council .

the response of a microscopic dielectric object to an optical field can profoundly affect its motion . a classical example of this influence is an optical trap , which can hold a particle in a tightly focused light beam @xcite . optical fields can also be used to arrange , guide or detect particles in appropriate light - field geometries @xcite . optical forces are ideally suited for manipulating microparticles in various systems , which are characterized by length scales ranging from hundreds of nanometers to hundreds of micrometers , forces ranging from femto- to nanonewton , and time scales ranging upward from a microsecond @xcite . transportation of particles of various sizes by light is of an immense growing interest caused by many potential applications @xcite . + manipulation of dielectric objects of a submicron size requires a strong optical confinement and high intensities than can be provided by diffraction - limited systems @xcite . in order to overcome these limitations it was proposed to use subwave length liquid - core slot waveguides @xcite , fiber or photonic crystal ( phc ) waveguides and cavities @xcite . the technique simultaneously makes use of near - field optical forces to confine particles inside the waveguide and scattering / absorption forces to transport it . the ability of the slot or the phc waveguides to condense the accessible electromagnetic energy to spatial scales as small as 60 nm also allows researchers to overcome the fundamental diffraction problem . however the consequence is that the cavity mode is strongly perturbed by the presence of a particle in its vicinity making standard phc cavities unsuitable for noticeable back action effects . a clear evidence of the back action between a resonant field in a photonic crystal cavity and a single dielectric nanoparticle through the optical gradient forces was presented in refs . @xcite . as a result , the motion of the particles can considerably modify the light propagation . the aim of the present paper is to study the time dependent back action effect for light propagation in a waveguide including a few dielectric microparticles with sizes comparable with the light wavelength , similar to an example shown in fig . [ figure : model](a ) . an analogous problem was considered by karsek _ @xcite who numerically studied by the coupled dipole method a longitudinal optical binding between two microparticles in a bessel beam . there are several aspects tremendously complicating the consideration of spherical particles . ( i ) spheres give rise to the problem of calculation of electromagnetic ( em ) fields of both polarizations especially in the near - field zone . this problem can be solved only numerically by expanding of the waveguide propagating solutions over vector spherical functions and using the lorenz - mie theory @xcite . ( ii ) for the scattering the mie resonances could play important role for the dielectric spheres of high refractive index . ( iii ) all translational and rotational degrees of freedom are to be included in the dynamics of each particle . in the present paper we model the particles with dielectric slabs inserted in a directional waveguide of a square cross - section @xmath1 as shown in fig . [ figure : model ] ( b ) . we take the perpendicular dimensions of the slabs very close to this cross - section . this allows us to consider only one - dimensional motion of particles and treat the problem analytically . this approach was applied for calculation of optical forces on dielectric particles in one - dimensional optical lattices @xcite by using the transfer matrix @xcite . this model of a classical optomechanical system @xcite preserves all qualitative features of the initial problem as it can be described by the transfer matrix and predicts the important result of temporal oscillations of light transmittance caused by light - induced motion . this paper is organized as follows . in sec . ii we remind the reader the formulas for the light pressure on a single particle in a waveguide . in sec . iii we formulate the model and consider motion of a single particle in the presence of a static `` scattering center '' inserted in the waveguide . in sec . iv we investigate regimes of motion of two mobile particles . section v presents the results for motion of a single particle inside a fabry - perot resonator . conclusions and discussion of the results are given in sec . motion of a particle in a vacuum- or air - filled waveguide is governed by the em force @xmath2 defined by the stress - tensor @xmath3 integrated over the surface elements @xmath4 @xcite @xmath5 where @xmath6 and @xmath7 are the cartesian indices . we concentrate on the basic propagating mode @xmath8 having the following solution @xcite @xmath9 where @xmath10 @xmath11 is the field amplitude , @xmath12 in the uniform waveguide , and the speed of light @xmath13 . to describe the em field we need to know the scattering properties of each slab specified by the reflection and transmission coefficients @xmath14 which can be expressed with the transfer matrix * @xmath15 * @xcite @xmath16 \sin(qa)},\nonumber\\ m_{12}&=&\displaystyle{\frac{i}{2}\left[\frac{q}{k}-\frac{k}{q}\right]\sin(qa)},~ m_{22}=m_{11}^ { * } , ~m_{21}=m_{12}^{*},\nonumber\\ t&=&\displaystyle{\frac{1}{m_{22}}},~~ r=\displaystyle{\frac{m_{12}}{m_{22}}},\end{aligned}\ ] ] where @xmath17 is the slab thickness . here @xmath18 is wave vector component along the @xmath19-axis given by : @xmath20 where @xmath21 is the dielectric constant of the slabs shown in fig . [ figure : singleslab ] . let us consider force acting on such a slab . its presence in the waveguide modifies the components of the electromagnetic field in the @xmath8 mode ( [ te ] ) as : @xmath22 @xmath23 @xmath24 substituting these solutions into eq . ( [ force ] ) we obtain the light pressure @xmath25 where @xmath26 the situation described in the previous section changes dramatically if another element , besides the mobile dielectric particle is inserted in the waveguide . in particular , we insert at @xmath27 an immobile particle ( `` scattering center '' ) characterized by light transmission and reflection coefficients , as shown in fig . [ figure : scatteringcenter ] . then the solution for the em field and therefore , the force acting on the mobile particle become dependent on its distance to the center and cause various regimes of the slab motion . here we concentrate on this motion driven by the optical force @xmath28 and the corresponding potential @xmath29 described by equation @xmath30 resulting , as we will show , in the time oscillations of the light transmittance through the waveguide . index @xmath31 enumerates the particle positioned on the left or on the right from the immobile center , @xmath32 is the particle mass ( @xmath33 is the material density ) , and @xmath34 is the linear drag coefficient for a particle in a medium of viscosity @xmath35 @xcite . in what follows we choose the dielectric constant of the slab @xmath36 ( glass ) , its width @xmath37 , and zero initial velocity . we neglect imaginary part of the dielectric constant and corresponding contribution into the optical force due to its smallness in the visible light frequency domain @xcite . we begin with the realization shown in fig . [ figure : scatteringcenter](a ) . similar to ref . @xcite , we write the equation for the ingoing and outgoing amplitudes of waves @xmath38 describing the em field components in each region of the waveguide ( fig . [ figure : scatteringcenter ] ) : @xmath39=\mathbf{m}\left[\begin{array}{c}1\\ r\end{array}\right],\quad \left[\begin{array}{c}t\\0\end{array}\right]=\mathbf{m}\left[\begin{array}{c } ae^{iky}\\ be^{-iky } \end{array}\right],\ ] ] where we assumed optical equivalence of the scattering center and the movable slab , @xmath40 is the distance between the particles , and the matrix @xmath15 is given by eq . ( [ m ] ) . the total transmission and reflection amplitudes can be expressed as @xcite @xmath41 substituting the solution of eq . ( [ ab ] ) into eq . ( [ force ] ) we find the forces acting on the slab ( @xmath42 ) and the scattering center ( @xmath43 ) as @xmath44,\nonumber\\ & & f_{\rm sc}(y)=p_{0}d^{2}\left[|a|^2+|b|^2-|t|^2\right]\nonumber\\ & & = -f_{l}(y)+2p_{0}d^{2}|r|^{2},\end{aligned}\ ] ] respectively . the forces depend only on the distance @xmath45 . + + + the magnitude of the force acting on the particle of the cross - section @xmath46 can be evaluated with eq . ( [ force ] ) as @xmath47 that is proportional to the injected into the waveguide light power @xmath48 @xcite . at @xmath49 mw , this yields the typical optical force @xmath50 of the order of 1 nn . the characteristic frequency of the oscillations , which we need for dimensionless equations of motion , can be estimated by an order of magnitude in the physical units as @xmath51 . since the dielectric particles of our interest with the size of the order of @xmath52 cm have masses @xmath53 of the order of 1 pg , these oscillations show characteristic frequencies of the order of @xmath54 khz @xcite , much lower than the light frequency . below we show as dependent on the initial conditions motion of particles can be bounded with characteristic frequency substantially less than @xmath55 or unbounded on times considerably larger than @xmath56 . the corresponding velocity of @xmath57 being of the order of 10 cm / s allows one to consider the light transmission adiabatically . on the other hand , the thermal velocity of a particle of the mass of 1 pg at the room temperature is of the order of 1 mm / s , which allows one to a good approximation neglect the random brownian motion . introducing the dimensionless coordinate via @xmath58 force as @xmath59 and mass @xmath60 ( leading to the time unit as @xmath56 ) , we can write eq . ( [ dynl ] ) in dimensionless form @xmath61 where @xmath62 is the dimensionless force acting on the @xmath63-th particle @xcite , and @xmath64 is expressed in the physical units as @xmath65 for water with @xmath66 @xmath67 , eq . ( [ gamma ] ) yields the dimensionless @xmath64 of the order of 10 for the injected light power @xmath68 of the order of 100 mw . for the air with @xmath69 , the value of @xmath64 at the same @xmath68 is of the order of 0.1 , corresponding to a relatively weak damping . with the increase in the light power , the effect of viscous friction decreases as @xmath70 for the realization corresponding to fig . [ figure : scatteringcenter](a ) , we show in fig . [ figure : leftslab](a ) the light transmittance through two particles , optical force @xmath71 and the corresponding potential @xmath72 where @xmath73 is the initial position of the particle . one can see that in the newtonian regime @xmath74 describing exactly particles in the vacuum or approximately in the air , we have either the bounded or unbounded time evolution of the positions , dependent on @xmath75 as presented in figs . [ figure : leftslab ] ( a ) and [ figure : leftslab ] ( b ) . the characteristic period of the potential is determined by the wave vector @xmath76 . two particles in the waveguide form a fabry - perot resonator ( fpr ) structure in which the transmittance @xmath77 shows sharp peaks when distance between the slab and the scattering center equals integer number of half wave lengths . then the wave function amplitude @xmath38 inside the resonator is maximal to give rise to resonant behavior of the optical force acting on the walls of the resonator . indeed , one can see that the force follows the light transmittance with sharp resonant negative dips . as the result the potential @xmath78 in ( [ ul ] ) acquires a tilted periodic shape with the particle dynamics qualitatively different from that in a simple periodic one . + respectively , as depends on the initial position of the particle , the time evolution shows oscillations or a motion until the particle touches the immobile element at @xmath79 as shown in fig . [ figure : leftslab](b ) . after this event the evolution needs a special analysis which goes beyond the scope of the present paper . the inset in fig . [ figure : leftslab](b ) shows that the choice of the initial position strongly changes the evolution of the light transmission through the particles with the left particle dragged by light . here we obtain oscillations with growing frequency since the distance between particles increases with time with acceleration caused by nonzero mean optical force . for the periodic oscillations of the left particle shown by the red line in fig . [ figure : leftslab](b ) the time oscillations of light transmission are periodic with a few harmonics . the appearance of this multi - frequency behavior is a result of anharmonicity of the binding potential @xmath80 shown in fig . [ figure : leftslab](a ) . + figure [ figure : rightslab ] shows the case corresponding to fig . [ figure : scatteringcenter](b ) . again the optical force follows the resonant dependence of the transmittance as a function of the distance between the particles with however positive peaks . unlike the case of fig . [ figure : scatteringcenter](a ) , the motion of the particle here is always unbounded . respectively , we have time oscillations of transmittance in fig . [ figure : rightslab ] ( b ) with growing frequency . effects of damping on the motion of the particles with the corresponding time evolution of light transmittance are shown in fig . [ figure : viscous ] . + + + for identical particles shown in fig . [ figure : twoslabspicture ] we obtain similarly to eqs . ( [ dynl ] ) and ( [ forces ] ) the following dimensionless equation of motion : @xmath81 where @xmath82 . the `` force '' @xmath83 depends only on the distance between particles @xmath84 and is shown in fig . [ figure : twoslabsmotion](a ) . surprisingly , the corresponding `` potential '' @xmath85 shows only periodic dependence on the distance @xmath86 different from the interaction considered in the previous section and similar to the optical binding of atomic clouds @xcite due to the standing em waves . the characteristic `` potential '' height @xmath87 can be estimated as @xmath88 . since we consider the light incident from the left , the inversion symmetry is broken resulting in @xmath89 . figure [ figure : twoslabsmotion ] demonstrates that the time dependence of the light transmittance strongly depends on the initial distance between the particles . for the distance @xmath90 when the potential is close to the minimum , the positions evolve in time approximately preserving the interparticle distance . respectively , the light transmittance oscillates with time approximately harmonically as shown in the inset of fig . [ figure : twoslabsmotion](b ) . however if the initial position is far from the minimum , the nonparabolicity of the potential becomes important and the time dependence of the transmittance acquires higher harmonics . interactions presented in fig . [ figure : twoslabsmotion ] show more variety than the optical binding of small dielectric particles in the bessel beams @xcite and in the random fields @xcite . the analysis of the system of dielectric slabs in the waveguide allows us to consider analytically optical driving of a dielectric particle by em fields in resonant cavities . the cavity can be modeled by two immobile dielectric slabs and the particle is modeled by a mobile slab as shown in fig . [ figure : fprpicture ] . the solutions of the em field equations are given by the transfer matrices @xmath91=\mathbf{m}\left[\begin{array}{c}1\\ r\end{array}\right ] , \quad \left[\begin{array}{c}t\\0\end{array}\right]=\mathbf{m}\left[\begin{array}{c } ce^{ik(l - x - a)}\\ de^{-ik(l - x - a ) } \end{array}\right]\ ] ] for the walls of the resonator and @xmath92=\mathbf{m } \left[\begin{array}{c}ae^{ik(x - a)}\\ be^{-ik(x - a)}\end{array}\right]\ ] ] for the embedded movable slab . here the matrix @xmath15 is given by eq . ( [ m ] ) , @xmath93 has the elements @xmath94 \sin(q_ma)},\\ m_{12}&=&\displaystyle{\frac{i}{2}\left[\frac{q_m}{k}-\frac{k}{q_m}\right]\sin(q_ma)},~ m_{22}=m_{11}^ { * } , ~m_{21}=m_{12}^{*},\nonumber\end{aligned}\ ] ] and @xmath95 similar to eq . ( [ force1 ] ) we have for the optical pressure on the mobile particle @xcite @xmath96.\ ] ] the corresponding potential @xmath97 is presented in fig . [ figure : fprpotential ] . one can see that it strongly depends on the dielectric constant of the walls of the resonator , i.e. on its openness . for @xmath98 close to @xmath21 the potential holds local minima capable to bind the particle at the corresponding positions . this result is reminiscence of electron transmission through the well potential relief with two different potential wells @xcite . time evolution of the particle position in the fpr is shown in fig . [ figure : fprmotion](a ) for two initial @xmath99 the first position , @xmath100 yields oscillations in the vicinity of a local potential minimum shown in fig . [ figure : fprpotential ] . an extremely nonlinear profile of the potential over the particle position gives rise to the shape of the corresponding time oscillations of the light transmittance shown in fig . [ figure : fprmotion](b ) by dashed red line . the second choice , @xmath101 corresponds to the accelerated time evolution until the particle will reach the right wall . this motion corresponds to the time behavior of the transmittance as shown in fig . [ figure : fprmotion](b ) by blue solid line . although the replacement of the particles by slabs as shown in fig . [ figure : model ] is a significant simplification , it preserves the main qualitative features of the light transmittance in a waveguide with embedded particles as described in general terms by a transfer - matrix dependent on the positions and optical properties of these particles . when one particle is inserted in a waveguide , it is subject to a radiation pressure of the propagating light . this pressure does not depend on the position of the particle and produces its constant acceleration in the vacuum or drags it in a viscous medium with a constant velocity . the transmittance of light through the particle remains position and time - independent . the situation changes dramatically if at least two particles are inserted in the waveguide . because of different light pressure acting on the particles the interparticle distance changes with time . respectively , the transmittance given by the fabry - perot resonator transfer matrix equations ( [ rt ] ) acquires a time dependence . to describe the light - induced interaction between the particles one can introduce an effective system - dependent potential this potential usually has a tilted ( or a simple , as depends on the system realization ) periodic shape , where the evolution of the interparticle distance can be bounded or unbounded . as a result , the light transmittance shows a rich variety of time - dependent behaviors in the form of time oscillations either with a few harmonics for a bounded motion or with a growing frequency for the unbounded one . the characteristic period of the oscillations in the light transmittance shown in the paper is of the order of @xmath102 s for the propagating light power of the order of 100 mw . therefore , by changing the laser light power and direction one can achieve different regimes of the particles motion . similar modifications can be achieved by choosing different materials for the movable particles and static elements such as the `` scattering center '' in fig . [ figure : scatteringcenter ] or walls of the fabry - perot resonator in fig . [ figure : fprpicture ] . it is important to mention that recent publications confirm the presence of this phenomenon in different experimental set - ups : two rotating dielectric microparticles @xcite and density oscillations of swimming bacteria confined in microchambers @xcite . both systems show the characteristic frequencies of light modulation in the sound range . thus , the analysis of the time dependence of the light transmittance paves a way for manipulating and monitoring motion of the particles in optical waveguides . the work of a.f.s . was partially supported by grant 14 - 12 - 00266 from the russian science foundation . this work of e.y.s was supported by the university of basque country upv / ehu under program ufi 11/55 , fis2015 - 67161-p ( mineco / feder ) , and grupos consolidados upv / ehu del gobierno vasco ( it-472 - 10 ) . the numerical coefficient in the viscosity force expression depends on the shape of the partice with @xmath103 being , technically speaking , correct only for a perfect sphere . nevertheless , we will use it as an order - of - magnitude estimate .

we consider light - induced binding and motion of dielectric microparticles in an optical waveguide that gives rise to a back - action effect such as light transmission oscillating with time . modeling the particles by dielectric slabs allows us to solve the problem analytically and obtain a rich variety of dynamical regimes both for newtonian and damped motion . this variety is clearly reflected in temporal oscillations of the light transmission . the characteristic frequencies of the oscillations are within the ultrasound range of the order of @xmath0 hz for micron size particles and injected power of the order of 100 mw . in addition , we consider driven by propagating light dynamics of a dielectric particle inside a fabry - perot resonator . these phenomena pave a way for optical driving and monitoring of motion of particles in waveguides and resonators .

SECTION 1. SHORT TITLE. This Act may be cited as the ``Southwest Border Port-of-Entry Infrastructure Improvement Act''. SEC. 2. DEFINITIONS. In this Act: (1) Agreement.--The term ``Agreement'' means the Agreement Between the Government of the United States of America and the Government of the United Mexican States Concerning the Establishment of a Border Environment Cooperation Commission and a North American Development Bank, done at Washington and Mexico City November 16 and 18, 1993 (TIAS 12516). (2) Border environment cooperation commission.--The term ``Border Environmental Cooperation Commission'' means the commission established in chapter I of the Agreement. (3) Commissioner.--The term ``Commissioner'' means the Commissioner of Customs. (4) North american development bank.--The term ``North American Development Bank'' means the bank established in chapter II of the Agreement. (5) Southwest border.--The term ``Southwest border'' has the same meaning given the term ``border region'' in article V of chapter III of the Agreement. TITLE I--UNITED STATES SOUTHWEST BORDER INFRASTRUCTURE IMPROVEMENT PROJECTS SEC. 101. UNITED STATES INFRASTRUCTURE PROJECTS. (a) Update and Development of Priorities.-- (1) In general.--The Commissioner of Customs, in consultation with the Secretary of Agriculture and the Commissioner of Immigration and Naturalization, shall, not later than 6 months after the date of enactment of this Act, update the Ports of Entry Infrastructure Assessment Study submitted by the Customs Service pursuant to Public Law 106-58 (commonly known as the ``Treasury and General Government Appropriations Act, 2000'') (113 Stat. 430), and develop priorities for port-of-entry infrastructure improvement projects in the United States along the Southwest border. (2) Criteria.--The Commissioner shall update the Study and develop priorities for projects under paragraph (1) based on the positive impact that completion of a project will have on facilitating trade across the Southwest border. (3) Port to federal highway connections.--The update and priorities developed under paragraph (1) may include port to Federal highway connections in the United States. (4) Publication and opportunity to comment.--Prior to finalizing the update and the priority of projects under paragraph (1), the Commissioner shall publish the proposed update and priorities in the Federal Register and provide an opportunity for public comment. (b) Effect of Prioritization.-- (1) In general.--The Commissioner shall implement port-of- entry infrastructure improvement projects in the United States along the Southwest border in accordance with the priority of projects developed through the update. (2) Divergence from priorities.--The Commissioner may diverge from the priorities developed through the update if the Commissioner finds that significantly changed circumstances, such as changes in infrastructure in Mexico, compellingly alter the need for a project in the United States. (c) Use of Local Businesses.--Every effort shall be made to use local businesses to carry out projects under this title. SEC. 102. AUTHORIZATION OF APPROPRIATIONS. There are authorized to be appropriated $100,000,000 for each of fiscal years 2002 through 2006, and such other sums as may be necessary in any succeeding fiscal year, to carry out the provisions of this title. TITLE II--SOUTHWEST BORDER INFRASTRUCTURE INCENTIVE INITIATIVE SEC. 201. SOUTHWEST BORDER INFRASTRUCTURE FUND. (a) Establishment.-- (1) In general.--There is established in the Department of Transportation a fund known as the ``Southwest Border Infrastructure Fund'' (in this title referred to as the ``Fund'') which shall consist of such sums as may be available in appropriations Acts. (2) Purpose.--The purpose of the Fund shall be to award grants under section 202. (b) Consultation.--In establishing the Fund, the Secretary of Transportation shall consult with the Administrator of the Environmental Protection Agency, and may use the Border Environment Infrastructure Fund of the North American Development Bank as a model. SEC. 202. SOUTHWEST BORDER INFRASTRUCTURE IMPROVEMENT GRANTS. (a) Program Authorized.--The Secretary of Transportation is authorized to make grants from the Fund to an eligible applicant through the North American Development Bank to pay the United States contribution of the costs of projects described in subsection (b). (b) Authorized Activities.-- (1) In general.--A project described in this subsection means a project to develop the physical port-of-entry infrastructure along the Southwest border in order to reduce the negative environmental impact, particularly with respect to air, soil, and water quality, associated with cross-border transportation. (2) Scope.--A project includes any activity associated with the financing, design, development, construction, and transition necessary to bring a port-of-entry infrastructure project described in paragraph (1) to completion. (c) Eligibility.--For the purposes of this title, an eligible applicant is an entity certified as eligible for project financing by the Border Environmental Cooperation Commission. (d) Limitation.--A grant awarded under subsection (a) may not exceed $25,000,000. SEC. 203. APPLICATION. An entity that desires to receive a grant under this title shall submit an application through the Border Environmental Cooperation Commission to the Secretary of Transportation at a time, in a manner, and accompanied by information as the Secretary may reasonably require. SEC. 204. MATCHING REQUIREMENT. The Secretary of Transportation may not award a grant under section 202 unless the eligible applicant provides assurances that, with respect to the costs to be incurred in carrying out the project for which the grant is awarded, the eligible applicant will have available (directly or through funding from public or private entities) contributions in an amount equal to not less than $1 for every $1 of United States Government funds provided under the grant. SEC. 205. AUTHORIZATION OF APPROPRIATIONS. There are authorized to be appropriated to the Department of Transportation $75,000,000 for fiscal year 2002, and such other sums as may be necessary for each of the fiscal years 2003 through 2006, to carry out the provisions of this title. TITLE III--PORT-OF-ENTRY TECHNOLOGY DEMONSTRATION PROGRAM SEC. 301. ESTABLISHMENT OF PORT-OF-ENTRY TECHNOLOGY DEMONSTRATION PROGRAM. (a) In General.--The Secretary of the Treasury, acting through the Commissioner of Customs, shall establish a port-of-entry demonstration site to carry out the port-of-entry technology demonstration program described in section 302. (b) Criteria.--To ensure that the facility selected as the port-of- entry demonstration site has the most up-to-date design, contains sufficient space to conduct the demonstration program, has a traffic volume low enough to easily incorporate new technologies without interrupting normal processing activity, and can efficiently carry out demonstration and port-of-entry operations, the port-of-entry selected as the demonstration site shall-- (1) have been established not more than 5 years before the date of enactment of this Act; (2) consist of not less than 67 acres, with the possibility of expansion onto not less than 33 adjacent acres; and (3) service an average of not more than 31,000 vehicles per month in the 12 months preceding the date of enactment of this Act. SEC. 302. PORT-OF-ENTRY TECHNOLOGY DEMONSTRATION PROGRAM. (a) Purpose.--The purpose of the technology demonstration program is to carry out an ongoing program to test and evaluate new port-of- entry technologies, refine port-of-entry technologies and operational concepts, and train personnel under realistic conditions. (b) Technology Tested.--The Secretary shall test technologies that enhance port-of-entry operations, including those related to inspections, communications, port tracking, identification of persons and cargo, sensory devices, personal detection, and decision support. SEC. 303. REPORT. (a) In General.--Not later than 1 year after the date of enactment of this Act, and annually thereafter, the Secretary of the Treasury shall submit to Congress a report on the activities of the demonstration site and technology program established under this title. (b) Content.--The report shall include an assessment by the Secretary of the Treasury of the feasibility of incorporating any demonstrated technology throughout the United States Customs Service. SEC. 304. AUTHORIZATION OF APPROPRIATIONS. There are authorized to be appropriated to the Department of the Treasury $10,000,000 for fiscal year 2002, and such other sums as may be necessary for each of the fiscal years 2003 through 2006, to carry out the provisions of this title.

Southwest Border Port-of-Entry Infrastructure Improvement Act - Directs the Commissioner of Customs to update the Ports of Entry Infrastructure Assessment Study and develop priorities for port-of-entry infrastructure improvement projects in the United States (which may include port-to-Federal-highway connections) along the Southwest border.Establishes in the Department of Transportation the Southwest Border Infrastructure Fund. Authorizes the Secretary of Transportation to make grants from the Fund to an eligible applicant through the North American Development Bank to pay the U.S. contribution of costs for projects to develop the physical port-of-entry infrastructure along the Southwest border in order to reduce the negative environmental impact, particularly with respect to air, soil, and water quality, associated with cross-border transportation.Directs the Secretary of the Treasury to establish a site to carry out a port-of-entry technology demonstration program to test and evaluate new port-of-entry technologies, refine them as well as operational concepts, and train personnel under realistic conditions.

An electronics company hit by a string of suicides has raised wages in China - for the second time in less than a week. Foxconn will increase salaries at its Shenzhen plant by nearly 70% from as early as 1 October, if workers meet certain conditions. This is in addition to last week's announcement that wages would go up by 30%. There have been 10 suicides at the Taiwan firm's Shenzhen factory in 2010. Shares down A statement from Foxconn, which makes Apple's iPad and iPhone, said the second pay rise would lessen the pressure on workers to do overtime. "While overtime work was always voluntary, this wage increase will reduce overtime work as a personal necessity," the statement said. It said wages for production line employees at the firm's Shenzhen plant would rise from 1,200 yuan ($176, £122) to 2,000 yuan. To get that pay rise, workers first have to pass a performance test lasting three months. New employees will be put on probation for the same amount of time before getting the increase. Pay increases for workers at Foxconn's other Chinese plants - it employs more than 800,000 people in China - will be announced from July 1. "This wage increase has been instituted to safeguard the dignity of workers," said Foxconn's founder and chairman, Terry Gou. This latest announcement is in addition to last Wednesday's pay rise of 30% at all its factories in China. Foxconn, the trading name for Hon Hai Precision Industry Company, declined to say why there have been two large wage increases in less than a week. "I can't comment on that," said a company spokeswoman. The firm has been hit by a series of suicides this year. Ten people have killed themselves at its plant in Shenzhen, in southern China, which employs about 400,000 people. Three more apparently tried to take their own lives. Mr Gou said he was having trouble sleeping at night - and dreads an after-hours phone call, fearing it will be another suicide. Increasing pay is just one method to make sure workers are more "stable and comfortable". Foxconn has also employed psychiatrists and installed safety nets on buildings. While the pay rise is good for workers, investors took a different view. The company's shares fell sharply on the Taiwan stock market following the announcement of the second pay rise. Trading in the company's shares on the Hong Kong Exchange was suspended on Monday. ||||| A couple stand on a footbridge in front of nets, newly installed to prevent workers from jumping to their deaths, outside one of Foxconn's factory buildings in the township of Longhua, in southern Guangdong province June 2, 2010. TAIPEI | TAIPEI (Reuters) - iPhone maker Foxconn (2038.HK) has offered workers at its Shenzhen manufacturing hub in China a 66 percent performance-based pay rise as it tries to deal with the fallout from a spate suicides there. Foxconn, owned by Taiwan contract electronics maker Hon Hai Precision Industry (2317.TW), said on Sunday production line workers would be able to earn 2,000 yuan a month if they pass a three-month performance review. It did not give details of the evaluation process. The latest hike, to take effect as early as October 1, comes on top of a 30 percent across the board rise in the cash part of wages announced last week and means wages will be more than double since employee suicides became a major issue last month. Before last week's rise, workers earned 900 yuan a month. "This wage increase has been instituted to safeguard the dignity of workers, accelerate economic transformation, support Foxconn's long-term objective of continued evolution from a manufacturing leader to a technology leader, and to rally and sustain the best of our workforce," said Foxconn founder and Chairman Terry Gou in a statement. "We are working diligently to ensure that our workplace standards and remuneration not only continue to meet the rapidly changing needs of our employees, but that they are best in class." A total of 10 workers have committed suicide at the company's base in Longhua, southern China this year. They were all young migrant workers, among the millions of people who leave the poor hinterlands of China for the boom towns of the south and east coastal areas. Another worker died late in May from what his family said was overwork, a claim the company denied. The string of deaths have focused attention on working conditions in a region experiencing growing labor unrest and have triggered investigations by Apple (AAPL.O) and other big Foxconn clients, including Dell Inc (DELL.O). Apple CEO Steve Jobs called recent suicides at the plant troubling but said last week the site was not a sweatshop. Japan's Honda Motor (7267.T) offered a 24 percent wage hike to end a sometimes violent strike last week at a car parts plant in the same region, dubbed the world's workshop. Foxconn said wage increases for supervisors would be announced by August 1 and wage rises for plants elsewhere in China will be announced starting on July 1. It added that while overtime work was always voluntary, the wage increase would make working overtime a choice rather than a necessity for some employees.

– The owners of a suicide-plagued electronics plant in southern China have announced the second pay rise in under a week. Foxconn employees, who received a 30% across-the-board hike last week, will be eligible for a 66% performance-based pay rise if they pass a 3-month performance review, Reuters reports. Execs say the raises will reduce pressure on employees by making overtime a choice instead of necessity. "This wage increase has been instituted to safeguard the dignity of workers," said Foxconn's founder, who told reporters he was having trouble sleeping at night because he dreaded being called with the news of another worker suicide. The pay hikes, however, seem to have driven some investors to despair, the BBC notes: Foxconn shares plunged on the Hong Kong and Taiwan stock markets following the announcement.

our experiments begin with an ultracold mixture of @xmath1rb atoms in the @xmath5 state and @xmath0k atoms in the @xmath6 state , where @xmath7 is the total atomic angular momentum and @xmath8 is its projection onto the magnetic - field axis . the gas is confined in a far - detuned optical trap formed by a single beam of 1090 nm light focused to a 19 @xmath9 m waist . typical radial and axial trapping frequencies for our measurements are 450 hz and 6 hz , respectively , for rb @xcite . the k trap frequencies are higher than those of rb by a factor of 1.4 . we perform measurements above the phase transition temperature , @xmath10 , for bose einstein condensation ( bec ) of the @xmath1rb gas , so that the spatial distributions of the two clouds are well - matched . the number of atoms in each species is varied between @xmath11 and @xmath12 , and the temperature , @xmath13 , ranges from 250 nk to 770 nk . the atomic samples are prepared at a magnetic field that is several gauss above a broad s - wave feshbach resonance between the @xmath1rb and @xmath0k atoms . near the feshbach resonance , the scattering length is given by @xmath14 , with @xmath15 g , @xmath16 g , and @xmath17 @xmath18 , where @xmath18 is the bohr radius @xcite . we associate atoms into molecules by sweeping the magnetic field downwards across the resonance . one pair of magnetic coils is used to provide the bulk of the bias field , while a much smaller pair produces fast magnetic - field changes on the order of 10 g via controlled discharge of a 30 mf capacitor . with these coils , and employing open - loop corrections of transient magnetic fields caused by eddy currents @xcite , we can realize magnetic - field sweeps as fast as 300 g / ms . this allows us to explore the magnetic - sweep - rate dependence of molecule formation . in the presence of inelastic collisions , the detected number of molecules can differ from the number that was created . for example , a molecule - atom collision can result in vibrational relaxation of the molecule prior to detection @xcite . in addition , three - body inelastic collisions of atoms can lead to significant inelastic loss and heating as the magnetic field approaches a feshbach resonance . this modifies the atom gas conditions relevant to magnetoassociation . to minimize these effects , we carefully adjust the initial atom gas conditions and our magnetoassociation procedure . this facilitates a comparison of our data to theories that ignore losses and heating . the top part of fig . [ fig : beta ] illustrates a typical magnetoassociation sequence . first , the field is swept at a rate of 3.33 g / ms from 549.9 g down to 545.7 g to form feshbach molecules . to selectively image only the molecules , we sweep the field in 50 @xmath19 down to 544.7 g where unpaired @xmath0k atoms are transferred from the @xmath6 state to @xmath20 state using rf adiabatic rapid passage ( arp ) . at this magnetic field , the binding energy of the molecules is @xmath213 mhz @xcite , where @xmath22 is planck s constant , and the arp for atoms does not affect the molecules . to image the molecules , we then sweep the field in 65 @xmath19 back up to 546.0 g , where the molecules can be selectively imaged with light tuned to the cycling transition of @xmath0k . we find that the molecule number measured with this imaging technique is 85@xmath235% of the number measured after dissociating the molecules ( by sweeping the magnetic field upwards across the feshbach resonance ) and imaging the resulting atoms . therefore , when imaging the molecules below the feshbach resonance , we apply a multiplicative factor to correct the number for this measurement inefficiency . to minimize the loss of molecules due to inelastic collisions , we can release the gas from the optical trap after the molecules are formed . the sudden turn - off of the optical trap initiates an expansion of the gas that rapidly lowers the densities and switches off inelastic collisions . figure [ fig : beta ] shows the measured molecule number as a function of the time that the optical trap is turned off , @xmath24 , where @xmath25 is defined as the time when the magnetic field crosses the feshbach resonance . for @xmath26 we observe a decrease in the molecule number with increasing @xmath24 . we attribute this loss to inelastic collisions as the molecules spend more time in a relatively high density atom - molecule gas mixture in the trap . for @xmath27 , the magnetic field crosses the feshbach resonance after the gas starts expanding . for short expansion times , where @xmath28 , the measured number of molecules is constant within the measurement uncertainty . for longer expansion times , corresponding to @xmath29 , the rapidly dropping atom gas density reduces the efficiency of magnetoassociation for the 3.33 g / ms sweep rate . thus , we find @xmath30 gives the maximum number of molecules . . the error bars in all figures correspond to plus or minus the standard error obtained from repeated measurements . here , @xmath25 is defined as the time when @xmath31 crosses the feshbach resonance . for increasing @xmath26 , the molecules spend more time in the trap where atom - molecule collisions can cause loss . for comparison , the dashed line shows an exponential decay with a time constant of 2.7 ms . for @xmath27 , the expansion of the atom gas prior to magnetoassociation eventually reduces the efficiency of molecule creation for a fixed magnetic - field sweep rate . for this data , the initial atom gas has @xmath32 @xmath0k atoms and @xmath33 @xmath1rb atoms at @xmath34 nk ( @xmath35 ) . , scaledwidth=50.0% ] another issue is that inelastic collisions can cause loss and heating of the atoms even before molecules are formed . in particular , three - body recombination is an inelastic collision process for three atoms that produces a molecule plus an atom , both with excess kinetic energy . the rate for three - body recombination increases dramatically near the feshbach resonance . to estimate the size of this effect , we dissociate the molecules by sweeping the magnetic field back up across the feshbach resonance at a rate of 20 g / ms . since the adiabatic magnetoassociation process is reversible , this sequence should conserve the atom number in the absence of inelastic collisions . figure [ fig : alpha ] shows the measured fractional loss of @xmath1rb atoms as a function of the initial gas density . for a bose fermi mixture , the dominant three - body recombination process removes two bosons and one fermion from the trap . characterizing the initial atom conditions by the peak @xmath1rb density squared times the peak @xmath0k density , we find that the atom loss is below 10% as long as this density product remains lower than 2@xmath36 @xmath37 . the initial atom conditions for data in sections [ scn : lz ] and [ scn : saturation ] were chosen to satisfy this condition . rb atoms after a double magnetic - field sweep to create and then dissociate @xmath0k@xmath1rb feshbach molecules . the measured loss is plotted as a function of the product of the initial peak @xmath0k density and the peak @xmath1rb density squared . here , the initial atom gas has @xmath38 @xmath1rb atoms and @xmath39 @xmath0k atoms with a rb radial ( axial ) trap frequency of 490 ( 6 ) hz . the atom densities were varied by modulating the optical trap intensity to parametrically heat the cloud to temperatures between 490 nk and 730 nk . inset : magnetic double - sweep sequence . the optical trap is turned off at @xmath40=0 as the magnetic field crosses the feshbach resonance.,scaledwidth=50.0% ] although lower density conditions were chosen to characterize the molecule formation process , we note that our largest molecule clouds are produced from higher atom densities . for example , we created @xmath41 @xmath0k@xmath1rb molecules from a mixture whose density product @xmath42 was @xmath43 @xmath37 . the initial gas in this case had @xmath12 @xmath0k atoms and @xmath44 @xmath1rb atoms at 560 nk , where @xmath45 = 0.51 and @xmath46 = 2.0 . the efficiency of molecule creation , @xmath47 , which is defined here as the number of molecules divided by the lesser of the initial numbers of atoms of @xmath0k and @xmath1rb , @xmath48 , depends on the magnetic - field sweep rate as shown in fig . [ fig : lzcurve ] . only a small number of molecules are formed when the field sweeps too quickly across the feshbach resonance . as the sweep becomes slower and therefore more adiabatic , molecule production increases and finally saturates . the saturated conversion efficiency for bose fermi mixtures is typically well below unity , as is the case in fig . [ fig : lzcurve ] . in this section , we focus on the fast - sweep regime , where a simple extension of a two - body picture predicts that the molecule number increases linearly with the sweep duration @xcite . the maximum molecule conversion efficiency in the saturated regime is the topic of sec . [ scn : saturation ] . , vs the inverse magnetic - sweep rate , @xmath49 , of a 7 g linear ramp of the magnetic field across the feshbach resonance . the dashed line shows a fit to eq . ( [ eqn : generalizedlz ] ) , which gives @xmath50 g / ms and @xmath51 , or @xmath52 molecules , for this data . the initial gas consisted of @xmath53 @xmath0k atoms and @xmath54 @xmath1rb atoms at @xmath13= 490 nk . , scaledwidth=50.0% ] in order to extract information about the fast - sweep and saturated regimes independently , we fit the molecule conversion efficiency as a function of the magnetic - sweep rate @xmath55 to the following formula : @xmath56 here , @xmath57 is the saturated molecule conversion fraction and @xmath58 in the fast - sweep limit . in the fast - sweep regime , the molecule number is predicted to follow a landau zener - like behavior @xcite with the transition probability into the molecular state given by @xmath59 . for two particles in a box of volume @xmath60 , the landau zener parameter @xmath61 depends on the feshbach resonance parameters and is given by @xcite @xmath62 where @xmath63 and @xmath9 is the two - body reduced mass . interestingly , this result applies for thermal atoms ( fermions or bosons ) as well as for atoms in the motional ground - state , such as atoms in a bose einstein condensate @xcite . using classical probability theory , eq . ( [ eqn : dlz0 ] ) can be generalized to multiple particles simply by multiplying @xmath64 by the total number of available atom pairs to get the number of molecules @xcite . using a local density approximation , the molecule density at position @xmath65 is then given by @xmath66 integrating eq . ( [ eqn : dlz ] ) over the trapped atom gas distribution , and dividing by @xmath67 , gives @xmath68 where @xmath69 describes the density overlap of the two atom clouds . , vs the density overlap of the two atom clouds . the prediction for @xmath70 using the @xmath0k-@xmath1rb feshbach resonance parameters ( eq . ( [ eqn : gvalue ] ) ) is shown as a solid line . here , the atomic densities are varied by associating molecules at different times during expansion from the optical trap ( up to 1.2 ms ) , as well as by adjusting the evaporation trajectory and optical trap frequencies . for this data , the @xmath1rb radial ( axial ) trap frequency ranged from 360 to 520 hz ( 4 to 7 hz).,scaledwidth=50.0% ] plugging the relevant feshbach resonance parameters into eq . ( [ eqn : dlz ] ) yields @xmath71 this prediction for @xmath70 , which is shown as a solid line in fig . [ fig : lzparameter ] , agrees well with our measurements of @xmath70 as a function of the density overlap of the initial atom gas , @xmath72 . from this we conclude that magnetoassociation in the perturbative regime of fast magnetic - field sweeps behaves as expected in our bose fermi mixture . in the next section , we turn our attention to the saturated regime , which is important for experiments where one would like to create larger numbers of feshbach molecules . in the saturated regime of slow magnetic - field sweeps , molecule creation has been shown to depend on the entropy or phase - space density of the atom gas @xcite . a corresponding phenomenological model has successfully described molecule creation efficiency for homonuclear molecules in @xmath0k and @xmath73 gases as well as in heteronuclear mixtures @xmath73-@xmath74 @xcite , @xmath3-@xmath74 @xcite , and @xmath4-@xmath3 @xcite . while previous experimental work with @xmath3-@xmath74 trapped gas mixtures focused on rf association @xcite , we consider here magnetoassociation . figure [ fig : nmol ] shows the measured molecule creation efficiency @xmath47 as a function of @xmath45 of the @xmath0k gas , where @xmath75 is the fermi temperature . here , we varied the magnetic - field sweep rate , using the findings of sec . [ scn : lz ] to ensure that the sweeps were sufficiently slow that the molecule number was in the saturated regime . for this data , the number of @xmath0k atoms is larger than the number of @xmath1rb atoms . rb radial ( axial ) trap frequencies range from 360 to 550 hz ( 4 to 6 hz ) , and initial atom temperatures are between 250 nk and 770 nk . as was observed for homonuclear molecules @xcite , we find that the molecule conversion efficiency increases for higher initial atomic phase - space densities . , vs the initial @xmath45 of the @xmath0k atoms . the atom number ratio ranges from @xmath76 ( squares ) , @xmath77 ( circles ) , or @xmath78 ( triangles ) . the crosses include a correction to @xmath47 , based on an estimate of inelastic collisions between @xmath0k@xmath1rb molecules and @xmath1rb atoms . the estimated shift of @xmath47 is between 0.01 and 0.07 . molecule conversion efficiency increases for higher atomic phase - space density ( lower @xmath45 ) . bottom : the difference between the spss model and the data , @xmath79 , vs the initial @xmath45 of the @xmath0k atoms.,scaledwidth=50.0% ] we compare our results with the stochastic phase - space sampling ( spss ) model that has been used previously to treat homonuclear molecule formation @xcite . this semi - classical model is based on the idea that two atoms are able to pair if they lie within a volume of relative phase - space set by an adjustable parameter @xmath80 : @xmath81 where @xmath82 is the relative speed of the two atoms and @xmath83 is their separation . another property of the model is that atoms are only allowed to pair once ( i.e. , paired atoms are removed from further consideration ) . to determine the parameter @xmath80 in our system , we fit the molecule creation efficiency data from fig . [ fig : nmol ] to the spss model . we first use a monte - carlo calculation to generate atom distributions matching the initial conditions for each of our measurements . these atoms are then paired according to the criterion in eq . ( [ eqn : criterion ] ) to determine the molecule creation efficiency . a fit to the data with initial @xmath84 returns a value of @xmath85=0.38(3 ) . the error bar is dominated by a 10% systematic uncertainty in the measured conversion fraction . our measured @xmath85 for @xmath0k-@xmath1rb is consistent with the values @xmath86 found in @xmath0k and @xmath87 measured in @xmath88rb @xcite . in the bottom panel of fig . [ fig : nmol ] , we show that the spss model with @xmath85=0.38 significantly overestimates the conversion efficiency for atom clouds with low @xmath45 . we note that previous measurements for homonuclear feshbach molecules in @xmath0k agreed with spss predictions for @xmath45 as low as 0.05 @xcite . the failure of the spss model to describe our measurements in the quantum - degenerate regime may be due to heating by inelastic collisions , or may suggest that this model is inadequate for describing the production of _ fermionic _ molecules from quantum - degenerate atom gas mixtures . the maximum molecule conversion efficiency we observe in fig . [ fig : nmol ] is 45% , which occurs at our lowest @xmath45 for the initial @xmath0k gas . starting from even lower @xmath45 , or higher phase space density , would seem then to be an obvious way to increase the molecule conversion efficiency . however , going to higher initial phase space density in the bose fermi mixture would require creating a bec of @xmath1rb or having an even larger ratio of the number of fermionic atoms to bosonic atoms . in either case , this would result in a reduction in the spatial overlap of the bose gas and the fermi gas in the trap , as well as in momentum space , which will presumably decrease the molecule conversion efficiency . this effect has been observed below the bec transition temperature @xmath10 for heteronuclear mixtures @xcite . in addition , the high density of the bec can result in a rapid loss of molecules due to inelastic atom - molecule collisions . another challenge for heteronuclear molecules , such as fermionic feshbach molecules , is that differences in the masses , polarizabilities , and/or magnetic moments of the initial atoms can cause the two atom clouds to have different equilibrium positions in the trap . to measure the significance of this effect on the molecule conversion efficiency , we intentionally separated the @xmath0k and @xmath1rb clouds along the weak axial direction of the optical trap by applying a magnetic - field gradient before molecule formation . the results of this measurement are shown in fig . [ fig : separation ] , where we plot the saturated molecule conversion efficiency against the spatial offset of the two atom clouds . we find that the conversion efficiency drops when the spatial separation is significant compared to the root - mean - squared ( rms ) size of the @xmath1rb gas in the trap , @xmath89 . for the data in fig . [ fig : nmol ] , the spatial offset of the atom clouds in the axial direction is less than 1.2 @xmath89 and the calculated offset in the vertical direction due to differential gravitational sag is less than 0.3 @xmath89 . these relative displacements of the atom clouds were accounted for in the spss modeling . , as a function of the separation between the @xmath0k and @xmath1rb clouds in units of the width , @xmath89 , of the @xmath1rb cloud , which is the smaller of the two atom clouds . the solid curve shows an empirical fit to a gaussian with an rms width of 1.8(1 ) @xmath89 . for this data , molecules are created from @xmath90 @xmath1rb atoms and @xmath44 @xmath0k atoms at @xmath13 = 490 nk and @xmath46=1.6.,scaledwidth=50.0% ] we have studied the efficiency of converting atoms to fermionic feshbach molecules using magnetic sweeps in a regime where inelastic collision effects are minimized . we find that in the regime of fast magnetic - field sweeps , the molecule creation efficiency is proportional to the inverse sweep speed with a coefficient that depends only on the feshbach resonance parameters and the density overlap of the two atom clouds . for sufficiently slow magnetic sweeps , where the molecule number saturates , we find that the maximum conversion efficiency increases with increasing phase - space density . our measurements with @xmath91 for @xmath1rb and @xmath92 for @xmath0k agree with a phenomenological model having a single fit parameter . however , significant discrepancies are observed between this model and our data for a more quantum - degenerate fermi gas . the highest conversion efficiency , which is about 45% for our data , is achieved for larger numbers of fermionic atoms than bosonic atoms and for @xmath13 just above @xmath10 . 5 t. khler , k. gral , and p. s. julienne , rev . phys . * 78 * , 13111361 ( 2006 ) . c. chin , p. julienn , e. tiesinga , rev . * 82 * , 12251286 ( 2010 ) . f. ferlaino , s. knoop , and r. grimm , chapter 9 of _ cold molecules : theory , experiment , applications _ edited by r.v . krems , b. friedrich , and w. c. stwalley ( taylor & francis , london , 2009 ) . ni , s. ospelkaus , m. h. g. de miranda , a. peer , b. neyenhuis , j. j. zirbel , s. kotochigova , p. s. julienne , d. s. jin , and j. ye , science * 322 * , 231 ( 2008 ) . _ cold molecules : theory , experiment , applications _ edited by r.v . krems , b. friedrich , and w. c. stwalley ( taylor & francis , london , 2009 ) . j. j. zirbel , k .- k . ni , s. ospelkaus , t. l. nicholson , m. l. olsen , p. s. julienne , c. e. wieman , j. ye , and d. s. jin , phys . a * 78 * , 013416 ( 2008 ) . wu , j. w. park , p. ahmadi , s. will , and m. w. zwierlein , phys . lett . * 109 * , 085301 ( 2012 ) . heo , t. t. wang , c. a. christensen , t. m. rvachov , d. a. cotta , j .- h . choi , y .- r . lee , and w. ketterle , phys . a text**86 * * , 021602 ( 2012 ) . e. hodby , s. t. thompson , c. a. regal , m. greiner , a. c. wilson , d. s. jin , e. a. cornell , and c. e. wieman , phys . 94 * , 120402 ( 2005 ) . e. fratini and p. pieri , phys . a. * 81 * , 051605 ( 2010 ) . c. zhang , j. von stecher , and c. h. greene , phys . a * 85 * , 043615 ( 2012 ) . c. klempt , t. henninger , o. topic , m. scherer , l. kattner , e. tiemann , w. ertmer , and j. j. arlt , phys . a * 78 * , 061602(r ) ( 2008 ) . c. ospelkaus , s. ospelkaus , l. humbert , p. ernst , k. sengstock , and k. bongs , phys . * 97 * , 120402 ( 2006 ) . m. l. olsen , j. d. perreault , t. d. cumby , and d. s. jin , phys . a * 80 * , 030701(r ) ( 2009 ) . j. j. zirbel , k .- k . ni , s. ospelkaus , j. p. dincao , c. e. wieman , j. ye , and d. s. jin , phys . lett . * 100 * , 143201 ( 2008 ) . in the axial directions , a small magnetic - field curvature contributes to the trap potential at the level of a few hz . t. mukaiyama , j. r. abo - shaeer , k. xu , j. k. chin , and w. ketterle , phys . lett . * 92 * , 180402 ( 2004 ) . j. chwedeczuk , k. gral , t. khler , and p. s. julienne , phys . * 93 * , 260403 ( 2004 ) . c. zener , proc a * 137 * , 696 ( 1932 ) . j. e. williams , n. nygaard , and c. w. clark , new j. phys . * 8 * , 150 ( 2006 ) . s. watabe and t. nikuni , phys . rev . a * 77 * , 013616 ( 2008 ) . s. b. papp and c. e. wieman , phys . lett . * 97 * , 180404 ( 2006 ) . f. m. spiegelhalder , a. trenkwalder , d. naik , g. kerner , e. wille , g. hendl , f. schreck , and r. grimm , phys . rev . a * 81 * , 043637 ( 2010 ) .

we investigate magnetoassociation of ultracold fermionic feshbach molecules in a mixture of @xmath0k and @xmath1rb atoms , where we can create @xmath0k@xmath1rb molecules with a conversion efficiency as high as 45% . in the limit of fast magnetic sweeps and small molecule fraction , we find that the timescale of molecule production is accurately predicted by a parameter - free model that uses only the atomic densities , masses , and the known feshbach resonance parameters . we find that molecule production efficiency saturates for slower magnetic sweeps , at which point the maximum number of feshbach molecules depends primarily on the atoms phase - space density . at higher temperatures , our measurements agree with a phenomenological model that successfully describes the formation of bosonic molecules from either bose or fermi gases . however , for quantum degenerate atom gas mixtures , we measure significantly fewer molecules than this model predicts . weakly bound ultracold feshbach molecules can be created in an atomic gas by sweeping a magnetic field across a feshbach scattering resonance . this process , called magnetoassociation , has proven to be one of the most robust methods of feshbach molecule formation and is effective for both wide and narrow feshbach resonances as well as for gases of fermionic atoms , bosonic atoms , or mixtures of two atomic species @xcite . magnetoassociation was an essential initial step in the recent success in creating a gas of ultracold polar molecules , where the feshbach molecules were subsequently transferred to the ground ro - vibrational state @xcite . this experiment starts from an ultracold bose fermi gas mixture and creates fermionic @xmath0k@xmath1rb molecules . a quantum - degenerate fermi gas of polar molecules would be an important step towards achieving novel quantum phases of matter @xcite . however , the efficiency of the magnetoassociation is relatively low @xcite and this is a limiting factor in the number of ground - state molecules . fermionic feshbach molecules have also recently been created in @xmath2-@xmath3 and @xmath4-@xmath2 mixtures @xcite . in all of these experiments , the fraction of atoms converted to molecules is less than 30% . in contrast , molecule conversion efficiencies as high as 90% have been observed in homonuclear fermi gases , where this process has been studied in detail @xcite . the efficiency of magnetoassociation has been shown to depend on the magnetic - field sweep rate and on the phase - space density of the parent atomic gas . in the limit of sufficiently slow sweeps , a phenomenological model , which uses a pairing criteria based on the separation of two atoms in phase space and has a single fit parameter , was shown to describe the measured molecule creation efficiencies for different initial gas conditions @xcite . motivated by the relevance to ultracold polar molecule experiments as well as an interest in the nature of pairing in bose fermi mixtures @xcite , we report here an investigation of feshbach molecule magnetoassociation in an ultracold gas mixture of @xmath0k and @xmath1rb atoms . our measurements significantly extend the range of atom conditions studied for this mixture @xcite . we characterize the density - dependent timescale of magnetoassociation as well as the roles of competing inelastic processes . the remainder of this paper is organized as follows . we briefly summarize our experimental methods in sec . [ scn : procedure ] . section [ scn : loss ] describes the details of our magnetoassociation process with a particular focus on minimizing the effects of inelastic collisions . in sec . [ scn : lz ] we show that the sweep - rate dependence of @xmath0k@xmath1rb magnetoassociation follows a simple parameter - free model adapted from landau zener physics . in sec . [ scn : saturation ] we measure the saturated number of molecules that are produced under a wide range of atom conditions . these are compared against the stochastic phase - space sampling model described in ref . @xcite .

astrophysical evidences for the presence of black holes in certain x - ray binary systems as well as in the center of many galaxies are mounting @xcite . the fact that many observational data on black holes come from photons emitted by surrounding matter has motivated a more detailed investigation of radiation processes in these non - trivial backgrounds . in the early seventies , misner and collaborators championed a research program focusing on the synchrotron radiation emitted by fast moving charges orbiting black holes @xcite . since then , related studies have been pursued in various situations of interest in both classical and quantum frameworks ( see , e.g. , refs . @xcite-@xcite and references therein ) . in all these papers , however , attention was restricted to the radiation emitted by individual sources . as we are often interested in physical situations where a large number of charges are present ( e.g. , in accretion disks of compact objects ) , a more comprehensive analysis considering the combined emission of various sources would be welcome . in this paper , we investigate the scalar radiation emitted by an ensemble of sources in geodesic orbits around a schwarzschild black hole . we focus on the effect of the spacetime curvature on the radiation interference and pay particular attention to the transition from the radiating to the non - radiating ( magnetostatic " ) regime as the number of sources increases . the paper is organized as follows . in section [ sec : generalframework ] , we present the quantum field theory framework in which we work and establish the general formulas which will be used further to calculate the observables of interest . in section [ sec : applications ] , we apply the previous section results to investigate the scalar radiation emitted by certain source configurations and discuss the corresponding interference effects . section [ sec : finalremaks ] is dedicated to our final remarks . we assume natural units @xmath0 ( unless stated otherwise ) and metric signature @xmath1 . the spherically symmetric vacuum solution of einstein equations describing a black hole with mass @xmath2 is @xmath3 where @xmath4 . now , we introduce @xmath5 point scalar sources in uniform circular motion composing a thin disk at the equatorial plane , @xmath6 , with four - velocities @xmath7 where @xmath8 labels the sources , @xmath9 denotes the radial coordinates , and @xmath10 stands for the constant angular velocities as defined by asymptotic static observers . the corresponding total source density is given by @xmath11 where @xmath12 is normalized so that @xmath13 and @xmath14 is the proper 3-volume element orthogonal to @xmath15 . here @xmath16 and @xmath17 defines the initial angular positions . we minimally couple @xmath18 to a real massless scalar field @xmath19 according to the interaction lagrangian density @xmath20 the free scalar field operator @xmath21 satisfies the massless klein - gordon equation @xmath22 and can be expanded in terms of creation @xmath23 and annihilation @xmath24 operators as @xmath25 , \label{expansion}\ ] ] where @xmath26 = \delta(\omega-\omega ' ) \delta_{l l ' } \delta_{m m ' } \delta_{\alpha \alpha'}.\ ] ] here @xmath27 denotes the scalar particle frequency , @xmath28 is the azimuthal angular momentum quantum number , @xmath29 $ ] , @xmath30 labels outgoing modes ( @xmath31 ) from the past white hole horizon @xmath32 and incoming ones ( @xmath33 ) from the past null infinity @xmath34 . the positive - frequency orthonormal solutions ( with respect to the klein - gordon inner product @xcite ) satisfying @xmath35 are denoted by @xmath36 where @xmath37 are the usual spherical harmonic functions and @xmath38 satisfy the differential equation @xmath39 \psi^\alpha_{\omega l}(r ) = \omega^2 \psi^\alpha _ { \omega l } ( r ) \label{difeq}\ ] ] with @xmath40 . \label{v_s}\ ] ] for the sake of further convenience , it is useful to note that the scattering potential @xmath41 associated with minkowski spacetime can be obtained from @xmath42 by vanishing the black hole mass @xmath2 in eq . ( [ v_s ] ) : @xmath43 . in contrast to the schwarzschild case where @xmath44 can be expressed in terms of simple functions only in the low- and high - frequency regimes , the ( single ) set of normalizable radial functions in the minkowski case can be written in terms of usual spherical bessel functions as @xmath45 for all @xmath46 . in the low - frequency regime , the leading terms of the radial functions in the schwarzschild case are ( up to an arbitrary phase ) @xcite @xmath47 and @xmath48 where @xmath49 and @xmath50 are legendre functions . in the high - frequency regime , good results can be obtained using the wkb method @xcite : @xmath51 @xmath52 where @xmath53 is the dimensionless tortoise radial coordinate and @xmath54 . here , we have defined @xmath55 and the barrier factor @xmath56 where @xmath57 and @xmath58 stand for the classical turning points satisfying @xmath59 . the wkb method guaranties good results as long as @xmath60 but it is worthwhile to keep in mind that full numerical calculations show that this approximation satisfactorily captures the qualitative behavior of the radial functions in the low - frequency sector besides leading to excellent results in the high - frequency regime @xcite . our main observable of interest will be the emitted total power @xmath61 where @xmath62 @xmath63 is the total time as measured by asymptotic observers @xcite , and @xmath64 is the emission amplitude at the tree level associated with the emission of a scalar particle with quantum numbers @xmath65 into the boulware vacuum . we note that sources with @xmath66 give rise to terms proportional to @xmath67 in the amplitude @xmath68 . thus , @xmath69 will have no contributions coming from @xmath70 if we assume that @xmath71 . this is already codified in eq . ( [ totalpower ] ) . we now apply the formalism above to analyze the radiation emission from an ensemble of point sources in geodesic circular motion around a schwarzschild black hole . in this case , the corresponding angular velocities @xmath10 are related with the radial coordinates @xmath9 by @xmath72 it is particularly illuminating to investigate first the radiation interference restricting the number of sources to two , while allowing for an arbitrary angular separation between them . afterwards , we consider a system of @xmath5 sources equally spaced around an orbit , which will be suited to our discussion about the transition from the radiating to the non - radiating regime . we shall compare the results obtained in schwarzschild and minkowski spacetimes in order to extract the very influence of the spacetime curvature in the interference phenomenon . let us introduce a two - scalar source system by writing @xmath73 , where @xmath74 ( @xmath75 ) is given by eq . ( [ source ] ) . we define @xmath76 and @xmath77 , where the choice between @xmath78 and @xmath79 will simulate charged " and neutral " configurations , respectively . by fixing @xmath80 and @xmath81 , we have @xmath82 the emitted power @xmath83 , as given by eq . ( [ potgeneral ] ) , can be cast as @xmath84 where @xmath85 |\psi^\alpha_{m\omega_i \ ; l}(r_i)/r_i|^2 \nonumber \\ & \times & |y_{l m } ( \pi/2 , 0)|^2 \label{w1}\end{aligned}\ ] ] is the power emitted by each source @xmath75 separately and @xmath86 is the interference term associated with the two - scalar source system . the @xmath87 term implies that interference effects will only appear when @xmath88 . ( this is so because in this case there is a well - defined phase relationship between the emitted waves . ) hence , for sources in geodesic motion belonging to a thin disk , the interference term ( [ interference ] ) will only contribute when the sources share the same orbit : @xmath89 [ see eq . ( [ kepler ] ) ] . we restrict our attention to this case , since the one where the sources do not share the same orbit does not offer a major challenge ( once contributions coming from each source are summed up incoherently in the total power ) . is plotted for stable circular geodesics , i.e. @xmath90 ( @xmath91 ) , assuming various angular separations @xmath92 . here , the low - frequency approximations ( [ low1])-([low2 ] ) were used for the radial functions.,width=302 ] the total power ( [ totalpower ] ) associated with a two - scalar source system where the sources at @xmath93 have angular velocities @xmath94 and are separated by an angle @xmath92 can be calculated using eq . ( [ walphalm ] ) : @xmath95 . \label{w2tot}\end{aligned}\ ] ] in fig . [ w2stable ] , we plot the total emitted power @xmath96 as a function of @xmath94 for several angular separations @xmath92 . for the sake of visual clarity , we only consider sources at stable circular geodesics , @xmath97 . ( for @xmath98 the same monotonic increase is observed . ) we see that for the neutral configuration , the power is the largest for @xmath99 ( largest dipole moment ) and goes to zero as @xmath92 decreases . in the @xmath100 limit , superposed sources , no radiation is emitted , as expected . on the other hand , for the charged configuration , the emitted power is maximum for @xmath101 and minimum for @xmath99 , in which case @xmath102 and the dominant multipole contribution comes from @xmath103 . in order to plot fig . [ w2stable ] , we have used the low - frequency approximation given by eqs . ( [ low1])-([low2 ] ) for @xmath38 , since particles radiated away by sources at @xmath97 will typically possess frequencies @xmath46 satisfying @xmath104 ( we recall that for @xmath97 , the emitted radiation is dominated by waves with small @xmath105 ( see , e.g. , ref . @xcite ) . ) however , as the sources approach the innermost geodesic circular orbit , @xmath106 , higher angular momentum contributions become increasingly important and the summations in eq . ( [ totalpower ] ) must be carried over larger values of @xmath105 and @xmath107 . a useful relationship estimating the typical value of the magnetic quantum number , @xmath108 , carried by scalar particles radiated from relativistic sources at @xmath109 ( i.e. , @xmath110 , where @xmath111 is the angular velocity of light rays at @xmath112 ) is provided by @xmath113 in fig . [ w1xl ] , we plot the power @xmath114 radiated by a single source with @xmath115 , where [ see eq . ( [ w1 ] ) ] @xmath116 |\psi^\alpha_{m\omega \ ; l}(r)/r|^2 \nonumber \\ & \times & |y_{l m } ( \pi/2 , 0)|^2 \label{w^{(1)}}\end{aligned}\ ] ] as a function of @xmath105 ( @xmath117 ) and verify that eq . ( [ mtyp ] ) is in good agreement with the typical angular momentum radiated away . ( here , the wkb relations ( [ wkb1])-([wkb2 ] ) were used for the radial functions @xmath118 . ) emitted by a single relativistic source with angular velocity @xmath119 is plotted as a function of @xmath105 ( @xmath117 ) . the vertical dashed line indicates the @xmath108 value given by eq . ( [ mtyp ] ) and illustrates the good estimation provided by this expression for the typical value of the magnetic moment radiated away by sources at @xmath109 . here , ( [ wkb1])-([wkb2 ] ) were used for @xmath118.,width=283 ] as @xmath120 approaches @xmath121 , @xmath108 grows unboundedly and the number of relevant terms that must be considered in the summation of eq . ( [ w2tot ] ) increases accordingly . ) is plotted as a function of the angular separation @xmath92 for neutral and charged configurations for small ( @xmath122 ) and large ( @xmath123 ) angular velocities . in the small @xmath94 case , the curves are roughly sinusoidal which is typical for dipole emission ( @xmath124 ) , while in the large @xmath94 case , the curves present a non - monotonic behavior because of the significant contribution coming from higher multipoles . here , ( [ low1])-([low2 ] ) and ( [ wkb1])-([wkb2 ] ) were used for @xmath38 in the top and bottom graphs , respectively.,width=302 ] in fig . [ w2compare ] , we plot the total power @xmath96 as a function of @xmath92 assuming neutral and charged configurations for the cases where the sources have small ( @xmath125 ) and large ( @xmath115 ) angular velocities . in the small @xmath94 case , the curves are seen to be roughly proportional to @xmath126 following a dipole pattern @xcite . this is not so , however , in the large @xmath94 case , where the various multipole contributions drive the curves to become nontrivial . we note , in particular , that interference effectively vanishes for large enough @xmath92 in this case ( in the sense that the various multipole terms combine in such a way that both sources emit as if they were independent from each other ) , driving charged and neutral configurations to behave similarly . , is plotted as a function of @xmath94 for several angular separations @xmath92 . as @xmath94 approaches @xmath111 ( @xmath127 ) , this ratio goes to @xmath128 for every @xmath92 , implying that distinct sources emit irrespectively to each other for large enough @xmath94 . here , ( [ wkb1])-([wkb2 ] ) were used for the radial functions.,width=302 ] interference effects are expected to be important when the typical radiation wavelength @xmath129 is of order or larger than the distance @xmath130 between the sources . this leads to the following interference condition : @xmath131^{-1},\ ] ] where we have used that @xmath132 and @xmath133 . thus , for sources with @xmath134 ( i.e. , at @xmath109 ) , eq . ( [ mtyp ] ) implies that we should not expect interference unless the sources are quite close to each other . [ w2x2w1 ] exhibits the @xmath135 ratio as a function of @xmath94 for several angular separations @xmath92 , where we recall that @xmath96 denotes the total power emitted by the two - source system as given by eq . ( [ w2tot ] ) , while @xmath136 is twice the total power emitted by a single source . ( we fix @xmath94 to be the same in both cases . ) deviations from the unity indicate constructive ( @xmath137 ) and destructive ( @xmath138 ) interference . we can see from this graph how @xmath135 approaches the unity as @xmath94 gets closer to @xmath111 and interference tends to effectively vanish . ratio is plotted as a function of the angular separation @xmath92 for @xmath139 . the horizontal dashed lines correspond to @xmath140 . the variation of @xmath141 with respect to @xmath140 indicates the influence of the spacetime curvature on interference and is seen to increase in a non - trivial way as @xmath94 approaches @xmath111.,width=302 ] in order to investigate the role played by the spacetime curvature on interference , we must compare @xmath135 as calculated in schwarzschild ( s ) and minkowski ( m ) spacetimes , namely : @xmath142 where @xmath143 is the total power emitted by a single source as computed in minkowski spacetime assuming newtonian gravity . in this case , we relate the angular velocity @xmath94 with the radial coordinate @xmath120 using the kepler law , which formally reads as in eq . ( [ kepler ] ) although we should keep in mind that in the flat spacetime case all quantities refer to cartesian coordinates rather than to schwarzschild ones . @xmath144 is defined accordingly for a two - source system . rather than plotting eq . ( [ curvinterf ] ) , we exhibit in fig . [ interf2 ] @xmath145 and @xmath146 separately as functions of @xmath92 for various @xmath94 values assuming charged and neutral configurations . @xmath146 ( dotted horizontal lines ) carries information about the curvature influence on the radiation emitted by single sources and obviously does not depend on @xmath92 , while @xmath145 carries information about the curvature influence on interference as discussed in the context of eq . ( [ curvinterf ] ) . this is interesting to note that the term @xmath147 codifying the @xmath92 dependence in eq . ( [ w2tot ] ) is the same in minkowski and schwarzschild spacetimes because the angular structure of the corresponding metrics ( which is the relevant feature here ) is identical in both cases . the nontriviality of fig . [ interf2 ] comes from the fact that as one computes the _ total _ power , the sum in the quantum number @xmath105 couples the @xmath147 term to the radial functions , which are distinct in the curved and flat spacetimes . for low enough angular velocities ( see @xmath148 ) , only the @xmath149 contribution is relevant and such coupling is weak " . this is reflected in a small variation of the @xmath150 curve with respect to @xmath151 ( horizontal dashed line ) in the whole @xmath92 domain ( note the scale ) . now , as @xmath94 increases ( see @xmath152 ) , larger values of angular momenta are excited and the behavior of @xmath150 becomes nontrivial . thus , despite the fact that the same @xmath153 dependence appears in schwarzschild and minkowski cases , the coupling of this term to the proper radial functions generates a non - trivial interplay between spacetime geometry and interference . } $ ] is plotted as a function of @xmath5 for two orbits in the high - frequency regime , corresponding to @xmath154 and @xmath155 . as @xmath156 , @xmath157 } \to 0 $ ] and we recover the non - radiating limit . here , eqs . ( [ wkb1])-([wkb2 ] ) were used for @xmath118.,width=302 ] } ^{(n)}/(n w^{(1)})$ ] ratio is plotted as a function of @xmath5 for @xmath154 and @xmath158 . we note the existence of a region of constructive interference in the neutral case that is not present for the charged configuration . here , ( [ wkb1])-([wkb2 ] ) were used for @xmath118.,width=302 ] in this section we are interested in investigating the transition from the radiating to the non - radiating regime as the number of sources @xmath5 increases . they are assumed to be free and orbit the black hole with same angular velocity @xmath94 ( @xmath93 ) . the @xmath5-source system will be described by @xmath159}(x^\mu ) & = & \sum_{n=1}^n \frac{q}{\sqrt{-g } u^0 } \delta ( r - r ) \delta ( \theta - \pi /2 ) \nonumber \\ & \times & \delta ( \varphi -\omega t - ( n-1 ) \lambda ) \end{aligned}\ ] ] and @xmath160}(x^\mu ) & = & \sum_{n=1}^n \frac{q ( -1)^{n-1 } } { \sqrt{-g } u^0 } \delta ( r - r ) \delta ( \theta - \pi /2 ) \nonumber \\ & \times & \delta ( \varphi -\omega t - ( n-1 ) \lambda ) .\end{aligned}\ ] ] for charged and neutral configurations , respectively , where @xmath161 , i.e. the sources are equally spaced around the orbit . in the charged configuration , all sources have the same coupling @xmath162 , while in the neutral one sources with @xmath163 and @xmath164 appear alternately around the orbiting circle ( @xmath5 is assumed even here ) . the total power @xmath157}$ ] ( @xmath165 ) emitted by these @xmath5-source systems can be calculated : @xmath166}^{(n ) } ( \omega ) = \sum_{\alpha = \rightarrow}^\leftarrow \sum_{l=1}^\infty \sum_{m=1}^l w^{(1)}_{\alpha l m } ( \omega ) g_{[a ] m}^{(n ) } , \label{wn}\ ] ] where @xmath167 is given in eq . ( [ w^(1 ) ] ) and the interference factor can be cast as @xmath168 m } = \left\ { \begin{array}{lllll } n^2 & { \rm when } & m = k n & { \rm for \ , some } & k\in\mathbb{n}\\ 0 & { \rm when } & m \neq k n & { \rm for \ , every } & k\in\mathbb{n } \end{array}\right.\ ] ] and @xmath169 m } = \left\ { \begin{array}{lllll } n^2 & { \rm when } & m = ( 2k-1)n/2 & { \rm for \ , some } & k\in\mathbb{n}\\ 0 & { \rm when } & m \neq ( 2k-1)n/2 & { \rm for \ , every } & k\in\mathbb{n } \end{array}\right.\ ] ] in the charged and neutral cases , respectively . as discussed in fig . [ w1xl ] , the largest values acquired by @xmath170 happen for @xmath171 [ see eq . ( [ mtyp ] ) ] . the role played by @xmath172 m}$ ] is twofold : on one hand , it increases the power by a factor of @xmath173 and , on the other one , it restricts the sum in eq . ( [ wn ] ) to just a few significant terms : @xmath174 for the charged configuration and @xmath175 for the neutral one . thus , for low angular velocities ( in which case only small multipoles are relevant ) the emitted total power goes quickly to zero as the number of sources @xmath5 increases . notwithstanding , if @xmath134 , higher multipoles get important and the power radiated by a larger number of sources can be significant . in fig . [ wn ] , we show the total emitted power @xmath157}$ ] as a function of @xmath5 for two angular velocities in the high - frequency regime assuming neutral and charged configurations . we note that , as the orbit approaches the innermost circular geodesic , the number of sources which maximize the emitted power increases as well as the range of @xmath5 for which emission is significant . we also note that , for a given @xmath5 , the neutral configuration radiates typically more than the charged one . for large enough @xmath5 , however , interference takes control damping the emitted radiation . in fig . [ wnnw1 ] , we compare the total emitted power @xmath157}$ ] with @xmath5 times the total power emitted by a single source @xmath176 for two angular velocities in the high - frequency regime assuming neutral and charged configurations by plotting @xmath157}/(n w^{(1)})$ ] . for small enough @xmath5 , we see that @xmath157}/(n w^{(1 ) } ) \approx 1 $ ] , indicating that the contribution coming from each source is mostly independent from each other . as @xmath156 , however , interference becomes important and we recover the non - radiating regime . it is also interesting to note from fig . [ wnnw1 ] the existence of a region in which interference is constructive ( @xmath177 ) for the neutral configuration in contrast to the charged case . the fact that interference effects should become important when the wavelengths of the emitted waves ( of the order @xmath129 ) are larger than the distance @xmath178 between the sources allows us to estimate the number @xmath179 above which interference can not be neglected : @xmath180 for the angular velocities considered in figs . [ wn ] and [ wnnw1 ] , @xmath181 and @xmath182 for @xmath183 and @xmath184 , respectively . we have considered the radiation emitted by an ensemble of scalar sources in circular geodesic orbits around a schwarzschild black hole . interference associated with the emitted radiation was investigated and particular attention was given to the role played by the spacetime curvature . the non - radiating regime is recovered as the number of sources @xmath5 increases . finally , a simple useful result can be derived as follows : the power emitted by a scalar source following ultrarelativistic circular orbits in schwarzschild spacetime can be estimated to be @xmath185 when @xmath186 and @xmath187 . as a consequence , we get that the total emitted power associated with @xmath5 sources will be @xmath157 } \approx n w_{\delta}^{(1)}$ ] for @xmath188 and @xmath157 } \approx 0 $ ] for @xmath189 . the radiation component coming from the _ collective _ rotational motion of charges in highly ionized accretion disks orbiting black holes should be mostly damped by interference effects as the disk lies in the @xmath190 region . however , in the short time interval which charges spend at @xmath191 , the role played by interference should decrease as highly energetic radiation is emitted , in accordance with our results . the authors acknowledge full ( rm ) and partial ( gm ) financial support from fundao de amparo pesquisa do estado de so paulo ( fapesp ) . this work was in part inspired by conversations with r. opher to whom we are grateful . w. lewin and m. van der klis , _ compact stellar x - ray sources _ ( cambridge university press , cambridge , 2006 ) . r. genzel , f. eisenhauer , and s. gillessen , rev . phys . , * 82 * , 3121 ( 2010 ) . c. w. misner , r. a. breuer , d. r. brill , p. l. chrzanowski , h. g. hughes iii and c. m. pereira , phys . rev . lett . * 28 * , 998 ( 1972 ) . r. a. breuer , p. l. chrzanowski , h. g. hughes iii and c. w. misner , phys . d * 8 * , 4309 ( 1973 ) . e. poisson , phys . d * 52 * , 5719 ( 1995 ) . l. c. b. crispino , a. higuchi and g. e. a. matsas , class . quantum grav . * 17 * , 19 ( 2000 ) . l. m. burko , phys . rev . lett . * 84 * , 4529 ( 2000 ) . v. cardoso and j. p. s. lemos , phys . d * 65 * , 104033 ( 2002 ) . j. castieiras , l. c. b. crispino , r. murta and g. e. a. matsas , phys . d * 71 * , 104013 ( 2005 ) . l. c. b. crispino , a. r. r. da silva and g. e. a. matsas , phys . d * 79 * , 024004 ( 2009 ) .

we investigate the influence of the spacetime curvature on the interference of the radiation emitted by an ensemble of scalar sources in circular motion around a schwarzschild black hole . we pay particular attention to the transition from the radiating to the non - radiating regime as the number of sources increases .

there is increasing evidence that the majority of radio - loud agn at low redshift may be triggered by the accretion of hot gas . using a sample of 625 nearby groups and clusters , @xcite showed that the galaxies located closest to the centres of the clusters are more likely to host a radio - loud agn than other galaxies of similar stellar mass . @xcite analyzed _ chandra _ x - ray images of nine nearby x - ray luminous elliptical galaxies and showed that the jet power is tightly correlated with the bondi accretion rate onto the central black hole as estimated from the observed gas temperature and density profiles . it is also now recognized that the ` over - cooling problem ' at the centre of many galaxy clusters could be solved if radio - loud agn can heat surrounding gas . direct evidence of agn heating came with the discovery of x - ray cavities in the hot intracluster medium of a number of clusters and groups @xcite . some of these cavities coincide with extended lobes of radio emission produced by an agn in the central cluster galaxy but these hot bubbles may have been inflated by a previous cycle of nuclear activity . ] . the observations suggest that relativistic radio plasma displaces the x - ray emitting gas , generating turbulence and wave activity which heat the intracluster medium ( icm ) . agn feedback may also explain why low - temperature clusters are less x - ray luminous than predicted by a homologous scaling of the properties of hotter and more massive systems @xcite . the energy available from the central agn depends primarily on black hole accretion rate . in low - mass groups , it can be comparable to the total gravitational binding energy of the x - ray emitting gas , whereas high - mass clusters will be less strongly affected . as a result , relations such as @xmath1 ( x - ray luminosity vs temperature ) and @xmath2 ( x - ray luminosity vs velocity dispersion ) may be modified by radio - source heating . at smaller scales , agn feedback may play an important role in the formation and evolution of galaxies . recent work has demonstrated that it can plausibly explain the exponential cutoff at the bright end of the galaxy luminosity function , as well as the ` down - sizing ' of galactic star - formation activity at recent cosmic epochs @xcite . it may be that hot gas accretion , agn triggering , reheating of ambient gas , and suppression of agn activity occur in a cycle . accretion onto the central black hole may cause an outburst which removes the fuel supply for further radio activity . without agn feedback , the icm reverts to the state that triggered the outburst @xcite . although this picture is attractive , it remains to be verified in detail . we do not know the necessary conditions to trigger or to quench radio activity . we also do not understand the extent to which the global x - ray properties of the gas are modified by agn feedback(e.g . * ? ? ? * ; * ? ? ? * ; * ? ? ? only a few nearby clusters have deep enough x - ray images to reveal low - density cavities and permit the energetics of the gas to be studied in a spatially resolved fashion . if we wish to study how the global state of the x - ray gas is linked to agn activity in the central galaxy , we are forced to adopt a more statistical approach . it has long been known that the radio activity of cluster central galaxies is linked with the cooling flow or `` cool core '' phenomenon @xcite . this is the fact that many but not all massive clusters show a strong central peak in x - ray surface brightness , almost always coincident with the brightest cluster galaxy ( bcg ) , within which the directly inferred cooling time is less than the hubble time . the fraction of cool - core clusters with a radio - loud bcg is much higher than the fraction in the rest of the population . furthermore , because the cores add significantly to cluster luminosity and reduce the emission - weighted temperature , cool - core clusters fall systematically to one side of many of the x - ray scaling relations for clusters , e.g. the @xmath1 and @xmath2 relations@xcite . thus , in clusters of given velocity dispersion ( or mass ) , cool cores tend to be associated with enhanced x - ray luminosity , with massive central bcgs , and with radio - loud bcgs . given that the probability of radio activity increases with bcg mass@xcite , that both bcg mass and cluster x - ray luminosity increase with cluster mass@xcite , and that central black hole mass correlates tightly with galaxy mass@xcite , it seems clear that radio activity is tightly related to both black hole mass and the presence of a cooling hot atmosphere which can provide fuel . the exact causal relation between these phenomena remains unclear , however , and recent observational studies of lower mass systems appear , at least superficially , in conflict with the trends established for relatively massive clusters [ e.g. compare @xcite and @xcite with the above references ] . in this paper , we provide improved statistics for the relationship between cluster properties , both x - ray and optical , and the radio activity of their bcgs . we use a low redshift ( @xmath3 ) sample of 625 groups and clusters with carefully controlled bcg identifications . these were selected by @xcite from the sloan digital sky survey(sdss , * ? ? ? radio properties of these bcgs were determined following @xcite , who cross - matched the galaxies with the national radio astronomy observatory very large array sky survey ( nvss , * ? ? ? * ) and the faint images of the radio sky at twenty centimeters survey ( first , * ? ? ? * ) . by combining these two radio surveys , the identification of radio galaxies is both reasonably complete ( @xmath4 per cent ) and highly reliable ( @xmath5 per cent ) . radio - loud agn are then separated from star - forming galaxies with detectable radio emission on the basis of 4000 break strength@xcite . the sky coverage of this cluster sample is @xmath6 square degrees . the only x - ray survey with enough sky coverage to provide a reasonable match is the rosat all - sky survey(rass ) . because the rass is quite shallow , relatively few individual groups and clusters have sufficient x - ray flux for unambiguous detection , particularly at low velocity dispersion . the mean flux of such objects _ can _ be detected , however , by stacking their x - ray images ( e.g. * ? ? ? * ; * ? ? ? * ; * ? ? ? * ; * ? ? ? such stacking avoids selection biases that can occur if one analyses samples in which only the most x - ray luminous systems are detected . the limited resolution of rass maps and our stacking strategy , make it difficult to study the structure of the icm in detail , but we will see that concentration differences , reflecting the presence of cool cores , are nevertheless detectable . our paper is organized as follows . in section 2 , we introduce our sample of groups and clusters and describe their radio properties . in section 3 , we describe our x - ray detection techniques , both our method for detecting individual groups and clusters and our stacking technique . in section 4 , we study and compare the x - ray properties of clusters , emphasising how the @xmath2 relation and the surface brightness profiles of clusters vary with the radio properties of their bcgs . we discuss the contribution of the radio agn to the total x - ray emission in section 5.1 , while in section 5.2 , we discuss how the @xmath2 relation of clusters depends on the stellar properties of their bcgs . we present our conclusions in section 6 . we use the sample of groups and clusters of galaxies described in @xcite , which is drawn from the c4 cluster catalogue of the sdss data release 3 @xcite . the clusters lie in the redshift range @xmath7 . von der linden et al . developed improved algorithms for identifying the brightest galaxy ( the bcg ) and for measuring the velocity dispersion in each group or cluster . the velocity dispersion algorithm is designed to limit the effects of neighbouring groups and clusters . clusters and groups with very few galaxies are also discarded . the velocity dispersion @xmath0 is measured within the virial radius @xmath8 . the radio properties of the bcgs are taken from the catalogue of @xcite , which has been updated to the sdss data release 4 . the final sample includes 625 groups and clusters , with velocity dispersion spanning the range from @xmath9 to over 1000 @xmath10 ( see von der linden et al . 2007 for more details ) . 134 out of the 625 bcgs have radio fluxes larger than 5 mjy and are identified as radio - loud agn . five bcgs have radio fluxes which exceed 5 mjy but are clearly a result of star formation activity . there are 433 bcgs without a radio source brighter than 5mjy . the radio properties of the remainder are unknown because they lie outside the area covered by first . henceforth , we will refer to a group or cluster as ` radio - loud ' if its bcg has been identified as a radio - loud agn , and ` radio quiet ' if it is known to contain no radio source brighter than 5mjy . there are 134 radio - loud and 433 radio - quiet clusters in our sample . the fraction of radio - loud clusters in our sample is smaller than the fraction of clusters usually quoted as having cooling cores(@xmath11 according to * ? ? ? this may well be a selection effect since x - ray selected cluster samples are biased towards massive and x - ray luminous systems . in figure [ rlrq ] we show histograms of velocity dispersion @xmath0 and redshift @xmath12 for radio - loud and radio - quiet clusters . the two redshift distributions are very similar . the radio - loud clusters have slightly higher velocity dispersions than the radio - quiet objects . the median @xmath0 of radio - loud clusters is 428 @xmath10 , with 16 and 84 percentiles at 277 and 595 @xmath10 respectively . for radio - quiet clusters , the corresponding @xmath0 values are 392 , 252 and 583 @xmath10 . the figure also shows @xmath0 and @xmath12 distributions for a control sample of radio - quiet clusters ( dashed line ) . this was constructed by choosing the radio - quiet cluster closest in @xmath0 and @xmath12 to each radio - loud cluster ( see section [ sta ] ) . this matching procedure was introduced in order to minimize possible observationally induced biases when comparing the two samples . we use the rass to study the x - ray properties of our sample of groups and clusters . the rass mapped the sky in the soft x - ray band ( [email protected] ) with exposure time varying between 400 and 40,000s , depending on direction on the sky . the resolution of the rass images is 45 arcsec . two source catalogues were generated based on rass images through a maximum - likelihood ( ml ) search algorithm : the bright source catalogue @xcite and the faint source catalogue @xcite . however , these source catalogues are not optimized for extended sources . an extended source is likely to be deblended into several pieces by the ml search algorithm . there are carefully selected samples of x - ray clusters constructed from the rass data , e.g. the northern rosat all - sky galaxy cluster survey ( noras , * ? ? ? * ) and the rosat - eso flux - limited x - ray galaxy cluster survey ( reflex , * ? ? ? the reflex clusters , which have a completeness of @xmath14 at the flux limit of @xmath15 , are mainly located in the southern sky ( @xmath16 ) and have little overlap with our sdss clusters . for the noras clusters , the completeness is estimated to be @xmath17 at an x - ray flux of @xmath15 @xcite . our sample of groups and clusters has been selected from an optical galaxy catalogue . the centre of the cluster ( taken to be the position of the bcg ) and the virial radius of each cluster have already been determined . we use this extra information when studying their x - ray properties . we first check whether the position of the bcg of each cluster is consistent with a peak in x - ray emission ( section [ xcent ] ) . we then optimize the growth curve analysis algorithm of @xcite to detect the x - ray properties of our clusters individually ( section [ ind_det ] ) . finally , we develop a stacking algorithm to measure the mean x - ray properties of clusters as a function of their optical properties , independent of the detection limit of the rass ( section [ sta_det ] ) . before the x - ray luminosity of a cluster can be measured , the position of its centre must be determined . in the optical , the position of the bcg is usually taken to define the cluster centre . however , this position may be offset from the peak of the x - ray emission ( e.g. * ? ? ? * ; * ? ? ? * ) . in order understand whether such offsets are generic for clusters in our sample , we have developed an algorithm to determine the x - ray centre of a cluster . first , the ml search algorithm used to generate the rosat source catalogue is applied to the rass images @xcite . sources with detection likelihood @xmath18 in the @xmath19 kev band are retained . although an extended source is frequently de - blended into several pieces by this algorithm , the central peak is always identified . we match the position of each bcg with the ml detections using a tolerance of 5 arcmin in radius . x - ray sources found within this radius are considered as candidate x - ray centres . we find that 210 clusters have x - ray sources within a 5 arcmin radius and some clusters have several candidate x - ray centres . we then exclude candidates which are clearly not associated with the clusters by eye . if a point source is detected within the 5 arcmin search radius but significantly offset from the bcg , we assume that the source is a contaminant and is not part of the cluster . we show such an example in fig . b1 of appendix b. for clusters that still have more than one candidate x - ray centre , we pick the closest one . most of the sources we identified as the x - ray centres of clusters have extension likelihood greater than zero . this confirms that the x - ray emissions we identified are from the extended icm rather than from point - like agn . as we will show in section [ agncont ] , the x - ray emission from radio agn in the soft x - ray bands is expected to be much weaker than the x - ray emission we measure . our final sample of clusters with identified x - ray centres contains 157 objects . in figure [ offset ] we plot the offset between x - ray centre and optical centre ( i.e. the bcg position ) for these 157 clusters . the upper panel shows the offset in units of arcmin , while the lower panel shows the corresponding projected physical distance at the redshift of bcg . as can be seen , the x - ray centre is consistent with the bcg position in most cases . the typical offset is less than 2 armin ( @xmath20 3 rass pixels ) . this corresponds to a physical distance of around 50 kpc and so is consistent with the results of @xcite . + since the bcg positions are , in general , consistent with the x - ray centres , we will assume that the bcgs mark the centres of those clusters which are too faint to determine an x - ray centre directly with our algorithm . after the centre of each cluster has been determined , we use a growth curve analysis to count the number of photon events as function of radius and so to evaluate the cluster count rate . the background of each cluster is estimated from a centred annulus with inner radius @xmath8 and width 6 arcmin . to exclude contamination of this background estimate by discrete sources , we mask out all ml - detected ( @xmath18 ) sources inside this annulus . the surface brightness of the background is then calculated using the formula @xmath21 where the sum is over the photon events , @xmath22 is the effective exposure time at each photon position , and @xmath23 is the effective area of the annulus after the contaminating sources are masked out . the count rates within @xmath8 may also be contaminated by discrete x - ray sources unassociated with intracluster x - ray emission . as above , we therefore mask out all the ml - detected ( @xmath18 ) _ point _ sources that are located more than 2.25 arcmin ( 3 image pixels ) from the x - ray centre ) . ] . as already mentioned , an extended source is often detected multiple times by the ml algorithm . we therefore visually inspect all the ml sources and determine whether they are contaminants or part of the x - ray emission from the cluster . we show an example of this process in fig . b2 of appendix b. the cumulative source count rate as a function of radius is calculated by integrating the source counts in concentric rings and subtracting the background contribution . we integrate the source count rate to the x - ray extension radius @xmath24 . we determine this radius in two different ways , as described in @xcite . the first chooses the radius where the increase in source signal is less than the 1@xmath0 uncertainty in the count rate . the other is the plateau - fitting method , where the slope of the plateau ( in units of count rate per arcmin ) is less than 1 percent . these two methods give consistent results for clusters where the count rate profile can be determined with high s / n . for low s / n clusters , we choose the better determination of @xmath24 by visually checking the cumulative count rate profile . a source is said to have a significant x - ray detection if the counts within @xmath24 are three times larger than the poisson fluctuation in the photon counts . we detect 159 galaxy clusters individually according to this criterion . to convert the count rates into x - ray fluxes , we assume that the x - ray emission has a thermal spectrum with temperature @xmath25 , that the cluster gas has metal abundance equal to a third of the solar value @xcite and that interstellar absorption can be inferred from the galactic hydrogen column density @xcite . the gas temperature @xmath25 is assumed to follow the empirical scaling relation measured by @xcite , @xmath26 one might question whether this assumption is robust . most studies of the @xmath27 relation find that it does not depart significantly from the virial theorem expectation ( @xmath28 ) , even for low - mass galaxy groups ( e.g. * ? ? ? * ; * ? ? ? * ; * ? ? ? * ; * ? ? ? we further note that a variation in temperature of 50 percent makes less than a 5 percent difference to the flux estimate for most of our clusters . ) will be reinforced . ] throughout this paper we adopt a concordance @xmath29cdm cosmology with @xmath30 , @xmath31 , and @xmath32 . for some clusters , the total x - ray flux will exceed the flux measured within the extension radius @xmath24 . to estimate the flux that is missed outside @xmath24 , we adopt a @xmath33-model surface brightness distribution @xmath34 with @xmath35 , @xmath36 where @xmath37 is the central surface brightness and @xmath38 is the core radius and is assumed to be proportional to @xmath8 , with @xmath39 for radio - loud clusters and @xmath40 for radio - quiet clusters . values for radio - loud and radio - quiet clusters are based on the results from stacked images shown in section [ sbprof ] . this difference introduces a typical change of @xmath41 less than 5 percent . we would come to exactly the same conclusions if we adopted the same @xmath38 relation for all clusters , regardless of their radio properties . ] the extension correction factor @xmath42 is then defined as @xmath43 the exact values of @xmath38 and @xmath33 are far from certain for each individual cluster . as a result , the x - ray luminosities of clusters with large correction factors @xmath42 have larger errors . to account for this effect , we assume that the correction factor @xmath42 has an uncertainty of 0.1@xmath42 . we note that for a few clusters with sufficiently high s / n , we can apply a @xmath33 model fit and derive the extension correction factor @xmath42 . we find answers that are consistent with the estimates using equ . ( [ fe ] ) with an uncertainty of @xmath44% . the error on our estimate of @xmath41 for each cluster thus has two terms : the error of the flux estimation inside @xmath24 and the error on the correction factor @xmath42 . the x - ray properties of the 159 clusters that are individually detected in rass are listed in appendix a. the clusters that are individually detected in the rass are biased to the nearest and most x - ray luminous systems at each velocity dispersion . we can obtain an unbiased estimate of the average x - ray luminosity of our clusters by stacking objects with similar optical properties . we describe our stacking algorithm below . we divide the clusters into bins of velocity dispersion with a width of @xmath45 . within each velocity dispersion bin , the angular size of the clusters varies substantially because of the spread in redshift . ( recall that @xmath8 is proportional to @xmath0 . ) we centre each cluster image on the x - ray centre if this has been identified ( see section [ xcent ] ) and on the bcg otherwise . before stacking the images , we scale them all to the same size in units of @xmath8 and mask contaminating sources in the same way as in our analysis of individual clusters . the background is estimated as the average flux inside an annulus with inner radius @xmath8 and outer radius @xmath46 . the remaining steps in the detection algorithm ( determining the extension radius @xmath24 and count rate ) parallel those used for individual clusters . a stacked image is said to have a robust x - ray detection if the number of source photons within @xmath24 is also three times larger than the poisson fluctuation in the photon counts . for a stack of @xmath47 clusters with individual x - ray luminosities @xmath48 , redshifts @xmath49 , average galactic hydrogen columns @xmath50 and average rass effective exposure times @xmath22 , the number of source photons that should be detected in the rass , @xmath51 , is @xmath52 where @xmath53 is a function which converts the bolometric x - ray luminosity to observed count rate . since the x - ray luminosities of the sources in a stack are similar , the weighted average x - ray luminosity of the stack can be defined as @xmath54 we fit the surface brightness profile of each stack with a @xmath33 model to make the extension correction , and we correct the x - ray luminosity to the value expected within @xmath8 ( see section [ sbprof ] ) . in this section , we investigate how the x - ray properties of the clusters depend on the radio properties of their central bcgs . we focus on the comparison of the @xmath2 relations of radio - loud and radio - quiet clusters . we first show results for clusters that were detected individually in the x - ray images ( section [ ind ] ) . we then present results for stacked cluster samples ( section [ sta ] ) . as we showed in section [ ind_det ] , only @xmath55 percent ( 159 out of 625 ) of our clusters are individually detected in the rass . the solid histogram in figure [ fdet ] shows the detected fraction as function of velocity dispersion . as expected , the detected fraction is higher for higher velocity dispersion clusters . it increases from less than 15 per cent for groups with @xmath56 to more than 50 percent for clusters in the highest velocity dispersion bin . we find that 55 of the 134 radio - loud clusters and 88 of the 433 radio - quiet clusters are detected . the detected fractions as function of velocity dispersion for these two sub - samples are plotted in fig . [ fdet ] . as can be seen , the detected fraction is systematically higher for radio - loud than for radio - quiet clusters in all the velocity dispersion bins . + [ cols="<,^,^,^,^,^",options="header " , ] in the following , we show two example images where decisions about the x - ray detections had to be made by eye . the first example deals with the process of determining of the x - ray centre of the cluster ( section [ xcent ] ) . some x - ray sources , which are although inside the 5 arcmin aperture of the bcgs , are judged as contaminating sources rather than the x - ray centres of the clusters ( fig . b1 ) . the second example deals with the procedure of distinguishing contaminating x - ray sources from the extended x - ray emission of the cluster ( fig . ( @xmath20 8 arcimin ) from the cluster centre . the small circle shows the x - ray point source detected near the cluster centre . the angular distance from the x - ray source to the position of the bcg is @xmath203 arcmin . this x - ray source is judged to be a contaminant and not associated with the x - ray emission of the cluster . , title="fig : " ] + ( @xmath20 16.5 arcimin ) from the cluster centre , while the outer circle has a radius of @xmath57 arcmin . the area inside the ring from @xmath8 to @xmath57 arcmin is used for the background estimation . in this image , sources 48 and 55 are considered as contaminants , while sources 52 and 53 are considered as part of the extended x - ray emission from the cluster . , title="fig : " ] +

we use the rosat all - sky survey to study the x - ray properties of a sample of 625 groups and clusters of galaxies selected from the sloan digital sky survey . we stack clusters with similar velocity dispersions and investigate whether their average x - ray luminosities and surface brightness profiles vary with the radio activity level of their central galaxies . we find that at a given value of @xmath0 , clusters with a central radio agn have more concentrated x - ray surface brightness profiles , larger central galaxy masses , and higher x - ray luminosities than clusters with radio - quiet central galaxies . the enhancement in x - ray luminosity is more than a factor of two , is detected with better than 6@xmath0 significance , and can not be explained by x - ray emission from the radio agn itself . this difference is largely due to a subpopulation of radio - quiet , high velocity dispersion clusters with low mass central galaxies . these clusters are underluminous at x - ray wavelengths when compared to otherwise similar clusters where the central galaxy is radio - loud , more massive , or both .

Death penalty falls out of favor in America WASHINGTON — Most US states have now abandoned the death penalty in law or in practice, and the number of American convicts sentenced to execution each year is falling steadily, according to a new report. While 33 of the 50 states still have capital punishment on the books, only nine actually carried out an execution in 2012, and three quarters of the total number of executions were in four states in the South. According to an end-of-year survey by the Death Penalty Information Center, a non-profit educational group, this reflects a long-term trend that has seen the death penalty fall into disuse across most of the country. "Fewer states have carried out executions in 2012. The death penalty is becoming more isolated, more concentrated in a few states," DPIC director Richard Dieter told AFP, in an interview to present the report. The overall violent crime rate in America has fallen since a peak in 1991, but DPIC detects a more important trend of states and jurors turning their back on executions in favor of more common use of life sentences. The total number of executions this year was 43, down 75 percent from a high of 215 in 1996, and Connecticut became the 17th state to abolish the penalty. Taking the abolitionist states along with those that have allowed the death penalty to fall into de facto disuse, DPIC considers that 29, or more than half, the jurisdictions in the country no longer execute convicts. The US federal government and the US military can also execute prisoners, but the military has not done so since 1961 nor the United States since 2003, when 53-year-old convicted murderer Louis Jones was put to death. The most populous state, California, is holding 724 convicts on death row, a third more than second-place Florida, but has not executed anyone for seven years and came close to abolishing the penalty in a referendum this year. Even the states in the South, traditionally more quick to turn to capital punishment, have seen execution rates fall. Texas this year executed 15 prisoners but sentenced only nine more defendants to death row. "Things are shifting. There was a time when Texas had over 40 death sentences in a year," said Dieter, emphasizing that the drop in the number of sentences was as important as political moves to halt the practice. "That was a little over 10 years ago and now for the past few years we've had eight or nine death sentences, that's a dramatic drop and that will eventually affect executions in Texas," he said. Dieter explained the dramatic drop in death sentences as due, in part, to a new reluctance by jury members to convict in capital punishment cases, following revelations of previous miscarriages of justice. This year, 38-year-old Damon Thibodeaux was freed after 15 years on death row, after newly available DNA evidence cleared him of the 1997 rape and murder of his 14-year-old cousin, the 141st defendant to escape execution on appeal. In Texas, still the execution capital of the country, Carlos DeLuna -- executed in 1989 for the 1983 murder of a gas station attendant -- was posthumously cleared. "Around the country, juries are hesitant to impose the death penalty because new evidence may emerge, science may reveal something five or 10 years later, and now life without parole is available, it's an alternative," Dieter said. Copyright © 2013 AFP. All rights reserved. More » ||||| Just four states carried out more than three-fourths of the executions in the United States this year, while another 23 states have not put an inmate to death in 10 years, an anti-capital punishment group reports. The Death Penalty Information Center says in its annual report that Texas led the U.S., as it does every year, with 15 executions. Arizona, Mississippi and Oklahoma had 6 each. Together, the four states accounted for 33 of the 43 executions in the United States in 2012. The report also says that a handful of states were responsible for nearly two-thirds of death sentences imposed in 2012. Both executions and new death sentences are far below their peaks since executions resumed in 1977 following a halt imposed by the Supreme Court. Texas' 492 executions since 1977 are the most, by far. No more executions are scheduled before the end of the year, the group says. "By every count, the death penalty is declining and becoming less relevant. It's not turned to even in states that have been strong proponents of the death penalty. I'd even include Texas, which is sentencing many fewer people to death," said Richard Dieter, the center's executive director and author of the report. Dieter singled out Georgia, Louisiana, North Carolina, South Carolina and Virginia, none of which carried out an execution this year. And among those states, the only new death sentences were two in Georgia and one in Louisiana. The exoneration of people wrongly convicted, the availability of prison terms of life without parole and the cost of capital trials and the appeals process all are factors in the decline, Dieter said. The 43 executions equal the total in 2011 and were roughly half as many as in 2000. Ninety-eight prisoners were put to death in 1998, the busiest year for U.S. death chambers since 1977. Only nine states in all performed lethal-injection executions. Delaware, Florida, Idaho, Ohio and South Dakota were the others. The steady, reduced pace of executions was similar to the persistent decline in new death sentences imposed in 2012. Seventy-eight people convicted of murder have been sentenced to death so far, with another two such sentences possible, according to the report. Again, just four states accounted for nearly two-thirds of death sentences nationwide. Florida added 21 inmates to death row, California had 15 death sentences, Texas had 9 and Alabama, 7. California hasn't executed anyone in nearly seven years because of problems with its old death chamber, a shortage of one of the execution drugs and a broad challenge to executions. California's death row of more than 720 inmates is the largest in the U.S. As of April, 3,170 people were on death rows across the United States, the report said. Last month, California voters narrowly rejected an effort to abolish the death penalty. In April, Connecticut became the fifth state in five years, and 17th overall, to abolish the death penalty for future crimes, although it did not change the status of 11 people who were previously sentenced to death.

– US states executed 43 people this year, the same as last year, but a group that opposes the death penalty says 2012 stats show capital punishment is on the wane across the country. Some highlights from AFP and the AP: Nine states executed people this year, the smallest number in 20 years. Four states accounted for more than three-fourths of the executions: Texas (15), Arizona (6), Mississippi (6), and Oklahoma (6). Seventy-eight people have gotten death sentences this year, down from 315 in 1996. The new sentences were concentrated mostly in Texas, California, Florida, and Alabama. Connecticut became the 17th state to abolish the death penalty, bringing to 29 the number of states that either have no capital punishment or haven't executed anyone in five years.

quantum critical phenomena is extensively developing subject in modern condensed matter physics , in both theoretical and experimental frontiers.@xcite the most vivid manifestations of quantum phase transitions ( qpt ) arise in low - dimensional systems such as cuprates and iron pnictides . however , quantum critical behaviour is also found in three - dimensional ( 3d+time ) systems . well - known example of 3d compound with a magnetic quantum critical point ( qcp ) is tlcucl@xmath4.@xcite under normal conditions the material is in the magnetically disordered phase , while pressure drives qpt to the antiferromagnetically ordered neel phase . quantum critical properties of a system can be significantly influenced by the presence of impurities . for instance , substitution of cu atoms in the parent compound tlcucl@xmath4 with low concentration of nonmagnetic mg impurities creates an uncompensated spin @xmath5 at the impurity site , which induces magnetization around the impurities and even lead to the formation of a long - range magnetic order in the macroscopic volume of the crystal.@xcite in the magnetically disordered phase the magnetization cloud around each impurity exponentially decays over a few lattice spacings from the impurity . but in the vicinity of the qcp the effect of impurity - induced magnetization can be notably enhanced . experimental observations reveal an interplay between the impurity - induced staggered magnetization and a quantum criticality near the qcp . @xcite despite of the vast amount of theoretical work on the impurity - induced magnetization in quasi-1d and 2d systems ( see refs . @xcite and references therein ) , we are not aware of similar studies in the relation to 3d materials . in the present paper we consider a single impurity with spin @xmath0 embedded in the 3d antiferromagnet ( af ) , which is close to the qcp , separating magnetically disordered and magnetically ordered phases . conceptually , the problem is similar to the kondo effect ( see @xcite ) , since , as we show below , the spin cloud screens the impurity s spin at the qcp ( bose - kondo effect@xcite ) . we study the spatial distribution of the nonlocal spin density and the staggered magnetization induced by the impurity . we show , that when approaching the qcp from the disordered phase , the spin density around the impurity decays as @xmath1 with logarithmic corrections and the total spin accumulated in the delocalized cloud is equal to @xmath0 . we also demonstrate that the induced staggered magnetization decays as @xmath2 . closely related to the problem of the impurity - induced spin density and the impurity - induced neel order is a phenomenon of spin - charge separation ( scs ) . conventional definition of scs relies on the existence of two quasiparticles carrying spin and charge ( spinon and chargon ) , which is the case in 1d tomonaga - luttinger liquid of strongly interacting electrons.@xcite . by contrast , in higher spatial dimensions there are no known systems with scs in the conventional definition . however , scs exists in 2d models , such as hole - doped af @xcite . furthermore , the recent research @xcite reports pronounced scs in the vicinity of the magnetic qcp . in the latter case , the precise meaning of scs is different from scs in tomonaga - luttinger liquid . a hole creates a spin cloud around the charge with radius which diverges at the qcp . as a result the hole s spin becomes delocalized and spatially separated from the impurity s charge pinned to the impurity s site , that basically means scs . in the present article we show that such scs also occurs in 3d systems near the qcp . the paper is organized in the following way . in the section ii we introduce an effective field theory describing 3d af doped with a single impurity in the vicinity of the qcp . considering interaction of the doped af with a probe magnetic field , we introduce an operator of the spin density and explain how we calculate the induced spin density . here we also provide method of calculation of the staggered magnetization around the impurity . the rest of the paper is divided into two parts , which correspond to the two techniques of the calculations : self - consistent born approximation ( scba ) and renormalization group ( rg ) approach in @xmath6 dimensions . section iii refers to the calculation of the spin density in scba for the most physically interesting case of the impurity with spin @xmath7 . in the section iv we again calculate the impurity - induced nonlocal spin density , the local spin of the impurity and the staggered magnetization using rg technique . we also consider a semiclassical limit of the impurity with a large spin . we draw our conclusions in the section v. an example of a 3d lattice model which incorporates main features of magnetic quantum criticality is presented in fig . [ fig:3d_af_lattice ] . the model corresponds to the cubic lattice af consisting of spins @xmath7 at each site with weak @xmath8 bonds and strong @xmath9 bonds . the system has the qcp driven by parameter @xmath10 and located at @xmath11 , which separates the disordered magnetic phase of spin dimers at @xmath12 from the neel phase at @xmath13.@xcite this lattice model describes various properties of tlcucl@xmath4 near the pressure - driven qcp in zero and non - zero magnetic field.@xcite substitution of a @xmath7 cu@xmath14 ion with a spinless mg@xmath14 creates a vacancy ( hole ) . this is shown in fig . [ fig:3d_af_lattice ] . the vacancy acts as an effective impurity with the spin @xmath7 . the vacancy in the lattice induces a nonlocal magnetization cloud around the impurity site . in the present paper we will calculate spatial distribution of the spin density and the staggered magnetization in the spin cloud around the impurity . magnetic properties of the critical system are determined by low - energy magnetic excitations . the magnetic excitations are magnons in the neel phase and triplons in the paramagnetic phase . hereafter we use the term magnons for the both types of quasiparticles . the effective theory , which describes magnons in the vicinity of the qcp is based on the following lagrangian , see e.g. @xcite : @xmath15 where @xmath16 is the magnon field , @xmath17 is the magnon gap ( squared ) , @xmath18 is a four - magnon coupling constant , @xmath19 is the time derivative , @xmath20 is the three - dimensional gradient . hereafter we set plank constant and magnon speed equal to unity @xmath21 . in the disordered magnetic phase @xmath22 . near the qcp the magnon gap @xmath23 . the lagrangian ( [ initlagrangianmagn ] ) contains quadratic terms as well as quartic term @xmath24 , describing the magnon self - action . the magnon self - action results in the renormalization of the magnon gap @xmath25 in the lagrangian ( [ initlagrangianmagn ] ) . from the one - loop rg calculations@xcite it follows , that in the disordered phase the evolution of the renormalized gap is given by @xmath26^ { - \frac{n+2}{n+8}},\ ] ] where @xmath27 in the present case of the @xmath28 universality class system , and @xmath29 is a positive constant , determined by an ultraviolet scale @xmath30 . besides that , the @xmath31 term leads to renormalization of magnon quasiparticle residue.@xcite however , the change of the residue appears only in the two - loop renormalization group , and therefore is small . hence , for our purposes we drop out the self - action term from the lagrangian ( [ initlagrangianmagn ] ) and substitute the bare magnon gap to a renormalized value @xmath32 . the lagrangian of a non - interacting spin-@xmath0 impurity reads @xmath33 here @xmath34 is the @xmath35 component spinor . hereafter we set the energy of the non - interacting impurity to zero . the lagrangian which corresponds to the interaction between the impurity and the magnon field in the disordered phase is @xcite @xmath36 where @xmath37 is the coupling constant , @xmath38 are the operators of the impurity spin acting in the @xmath39-dimensional hilbert space . qcp . spins @xmath7 located at each site . thin lines denote weak @xmath8 bonds and thick lines denote strong @xmath9 bonds . a quantum phase transition between the neel and the dimerized paramagnetic phases occurs at @xmath40.@xcite the big blue sphere represents an impurity ( hole ) introduced into the lattice.,width=188 ] the interaction of the impurity with magnons leads to appearance of the nonlocal part of spin density @xmath41 . in order to find @xmath41 we use the lagrangian of interaction of the system with external magnetic field ( see , e.g. @xcite ) @xmath42 \right)+\frac{\left[\bm b\times \bm \phi\right]^2}{2 } + \psi^\dag\left(\bm s \cdot\bm b\right)\psi\,.\end{aligned}\ ] ] we have set here @xmath43 . note , that eq . ( [ eq : lagrangian_b ] ) is still valid , if the magnetic field @xmath44 is non - uniform . in the contrast to the majority of previous works , where @xmath44 is considered uniform , the non - uniformity of the probe magnetic field is crucial for the present paper . linear in @xmath44 terms in the lagrangian ( [ eq : lagrangian_b ] ) provide following expression for spin density : @xmath45 + \mathrm{h.c . } \right ) + \psi^\dag \bm s \psi \rangle \,=\nonumber\\ \bm s_{nl}(\bm r ) + \bm s_{imp } \delta(\bm r).\end{aligned}\ ] ] the brackets @xmath46 denote an averaging over the ground state of the system . the term @xmath47 + \mathrm{h.c . } \rangle$ ] in eq . ( [ eq : s_density_operator ] ) is the nonlocal part of the spin density @xmath48 , induced by the impurity . the subscript `` nl '' stands hereafter for `` nonlocal '' . the term @xmath49 in eq . ( [ eq : s_density_operator ] ) corresponds to the local spin @xmath50 at the impurity s site . in addition to the spin density we will consider the staggered magnetization , induced by the impurity . writing down an euler - lagrange equation for the magnon field @xmath51 from the action @xmath52 and taking expectation value of the result we obtain yukawa - like form of the staggered magnetization @xmath53 at the qcp the exponent in eq . ( [ eq : phi_def ] ) is close to unity and @xmath54 . therefore , in order to find corresponding prefactor , we only need to calculate the local spin at the impurity site @xmath50 . to find local as well as nonlocal components of the impurity - induced spin density we will proceed with the following procedure . we calculate the shift @xmath55 of the ground state energy , corresponding to the probe magnetic field @xmath56 . the energy shift of the system reads @xmath57 , therefore @xmath58 the spin density @xmath59 and the staggered magnetization @xmath60 are directed along the impurity spin @xmath61 ( @xmath62 is a unit vector ) , and due to spatial isotropy of the system depend only on @xmath63 . the ground state energy @xmath64 of the system is the position of a singularity of the retarded impurity s green s function @xmath65 and can be found from the dyson s equation @xmath66 where @xmath67 is the self - energy of the impurity at zero magnetic field , @xmath68 is the vertex function , corresponding to the interaction of the system with the probe magnetic field . note , that in eq . ( [ eq : groundenergyinb ] ) we need to keep only linear in @xmath69 terms . from the rotational symmetry properties the only possible `` kinematic '' structure of the vertex @xmath70 the vertex function can be split in local and nonlocal parts @xmath71 and ( a ) impurity spin , ( b ) nonlocal spin density . solid line corresponds to a bare @xmath72 impurity green s function , waivy line represents magnon , dashed line represents probe magnetic field @xmath44 . the cross on the magnon line corresponds to the magnon-@xmath44 vertex , provided by the term @xmath73 $ ] in the lagrangian ( [ eq : lagrangian_b ] ) . , width=264 ] ( 0,0 ) ( -137,50 ) ( -165,0 ) ( -220,20 ) ( 5,50 ) ( -35,0 ) ( -100,20 ) calculating the shift @xmath55 of the position of the singularity in the green s function @xmath65 due to the probe magnetic field and using the formula ( [ eq : s(r)_deriv_b ] ) we find the local and nonlocal components of spin density @xmath74 . below we will calculate spin density using two approaches : self - consistent born approximation ( for @xmath7 ) and renormalization group ( for arbitrary @xmath0 ) . standard approach for calculation of a single - fermion green s function is @xmath75 expansion for @xmath76 group , where @xmath27 is the number of magnon components . summation of leading terms in the @xmath75 expansion results in self - consistent born approximation ( scba ) , see fig . [ fig : g_scba ] . we will apply scba to the case of @xmath7 impurity only . as it will be demonstrated in section [ sec : rg_s ] , for @xmath77 corrections to impurity - magnon vertex , which are disregarded in scba , become relevant . therefore , in this case scba fails and application of rg technique is necessary . to consider interaction of the system with the probe magnetic field , we first calculate green s function of the impurity at zero magnetic field . the green s function of the impurity at @xmath78 is proportional to the identity matrix in the spin space @xmath79 . the dyson s equation for the green s function is graphically represented in fig . [ fig : g_scba ] . the analytical form of the equation reads : @xmath80 where the impurity self - energy is given by following expression @xmath81 here @xmath82 is the magnon dispersion , @xmath83 is the matrix element corresponding to emission of magnon with momentum @xmath84 by the impurity , @xmath85 is the magnon propagator . we expressed spin @xmath5 operators via pauli matrices @xmath86 . combinatorial factor @xmath87 in eq . ( [ eq : sigma_zero_b ] ) comes from summation over intermediate polarization state of magnon . ( 0,0 ) ( -162,33 ) ( -80,33 ) ( 0,33 ) ( -80,0 ) the sum over momentum @xmath84 in eq . ( [ eq : sigma_zero_b ] ) diverges at large @xmath88 , therefore we have to introduce ultraviolet cutoff @xmath30 . the parameter @xmath30 depends on particular realisation of system and can be estimated as inverse lattice spacing in the host af . solution to dyson s equation ( [ eq : g_scba ] ) near the qcp ( @xmath89 ) has the following form @xmath90 in the vicinity of the singularity point @xmath91 . formula ( [ eq : g_solution_scba ] ) is obtained with logarithmic accuracy , i.e. assuming that @xmath92 . the green s function ( [ eq : g_solution_scba ] ) has nontrivial analytic structure . at finite magnon gaps the quasiparticle pole at @xmath93 is separated by the gap @xmath94 from the incoherent part of the green s function . at the qcp , when @xmath89 the pole and the branching point singularity are merging . the quasiparticle residue of the impurity green s function @xmath95 vanishes in the vicinity of the qcp @xmath96 vanishing quasiparticle residue is the first signal of delocalization of the impurity - induced spin cloud and therefore indication of scs . @xcite typical value of the impurity - magnon coupling constant @xmath37 can be estimated on the basis of the lattice model , shown in fig . [ fig:3d_af_lattice ] . lattice calculations@xcite result in the value of the effective coupling constant @xmath97 , appearing in front of the logarithm in formula ( [ eq : g_solution_scba ] ) . therefore , the logarithmic corrections are significant in the vicinity of the qcp . analytical result ( [ eq : g_solution_scba ] ) for the impurity green s function can be compared with direct numerical solution of the dyson s equation ( [ eq : g_scba ] ) , corresponding plots for spectral functions @xmath98 are plotted in fig . [ fig : greenfunction ] . an artificial broadening @xmath99 is introduced in the numerical procedure and in analytical formula ( [ eq : g_solution_scba ] ) . we see an excellent agreement between the numerical and the analytical results . let us make a comment about the validity domain of scba for the results in the present section , and all following results , which will be derived in sections [ sec : s_nl_scba ] , [ sec : spin_impurity ] . formally , scba relies only on @xmath75 expansion of @xmath100 group , independently on the value of the coupling constant @xmath37 . scba is applicable for arbitrary @xmath37 , in contrast to rg method , which works only for @xmath101 . we will return to this discussion later , in the section [ sec : rg_coupl_z ] . impurity obtained in scba . panel ( a ) corresponds to the qcp ( @xmath102 ) ; panel ( b ) corresponds to magnon gap @xmath103 . effective coupling constant is set to @xmath104 . solid black line corresponds to green s function , calculated numerically , red dashed line corresponds to analytical formula ( [ eq : g_solution_scba ] ) . note , that on the panel ( a ) the position of pole and branching point are merging.,title="fig : " ] impurity obtained in scba . panel ( a ) corresponds to the qcp ( @xmath102 ) ; panel ( b ) corresponds to magnon gap @xmath103 . effective coupling constant is set to @xmath104 . solid black line corresponds to green s function , calculated numerically , red dashed line corresponds to analytical formula ( [ eq : g_solution_scba ] ) . note , that on the panel ( a ) the position of pole and branching point are merging.,title="fig : " ] ( 0,0 ) ( -150,70 ) ( -30,70 ) ( -65,-5 ) ( -190,-5 ) ( -130,15 ) ( -250,15 ) to evaluate nonlocal spin density induced by the impurity at the distances @xmath105 , we substitute the green s function pole position @xmath106 into eq . ( [ eq : groundenergyinb ] ) , expand it in @xmath55 up to the first order and use eq . ( [ eq : s(r)_deriv_b ] ) . the result reads @xmath107 leading in coupling constant @xmath37 contribution to the vertex @xmath108 is represented by the feynman diagram shown in fig . [ fig : gamma ] , ( b ) . the analytical expression for the diagram is following @xmath109 d_{\beta \alpha}(\omega , \bm q)\ , , \nonumber\\\end{aligned}\ ] ] where @xmath110 is the bare retarded green s function of a non - interacting impurity . expression in square brackets corresponds to magnon - probe magnetic field vertex , which we show in fig . [ fig : gamma ] , ( b ) as a circle with a cross inside . scba equation for vertex @xmath111 is graphically represented in fig . [ fig : gamma_scba ] . analytical form of the equation for the vertex is @xmath112 where @xmath113 corresponds to the first term in the rhs of the diagrammatic equation in fig . [ fig : gamma_scba ] and reads @xmath114 to obtain expressions ( [ eq : sigmaexact ] ) and ( [ eq : gamma_0 ] ) we performed integration over @xmath115 in the rhs of the original scba equation , shown in fig . [ fig : gamma_scba ] . factor @xmath116 in eq . ( [ eq : sigmaexact ] ) comes from algebraic identity for pauli matrices @xmath117 . fformula ( [ eq : gamma_0 ] ) follows from ( [ eq : sigmab_0 ] ) , where the bare impurity green s function is changed to the `` dressed '' green s function @xmath118 , shown in fig . [ fig : g_scba ] . .,width=302 ] ( 0,0 ) ( -223,10 ) ( -195,10 ) ( -92,10 ) ( -46,10 ) to find @xmath119 we solve numerically eq . ( [ eq : sigmaexact ] ) for the vertex @xmath120 and substitute the result together with the quasiparticle residue @xmath121 , obtained from numerical solution of dyson s equation ( [ eq : g_scba ] ) , to eq . ( [ eq : s_nloc_zg ] ) . solution to eq . ( [ eq : sigmaexact ] ) has been found iteratively , starting iterations from the @xmath122 . the results of the calculation of the spin density @xmath119 for different values of the magnon gap @xmath94 and coupling constant @xmath37 are presented in fig . [ figspindistr ] . for the purpose of computational efficiency we used spherical cutoff @xmath123 in integrals in eq . ( [ eq : sigmaexact ] ) and ( [ eq : gamma_0 ] ) , instead of integrating over a cubic brillouin zone . this cutoff scheme resulted in appearance of significant @xmath124-oscillations in the induced spin - density @xmath119 , where the period of oscillations is @xmath125 and the amplitude of the oscillations decaying with increasing @xmath124 . it is clear that these oscillations are by - products of the rigid spherical cutoff and will be notably suppressed , if one performs proper 3d - integration over the cubic brillouin zone . hence , in fig . ( [ figspindistr ] ) we plot numerical data for the spin - density , averaged over the period of the oscillations . ( multiplied by @xmath126 ) induced by @xmath7 impurity as a function of dimensionless distance @xmath127 calculated in scba . points represent numerical results for different values of magnon gap and effective coupling constant @xmath128 . squares correspond to @xmath129 , triangles correspond to @xmath130 ; filled markers represent @xmath131 , open markers correspond to @xmath104 . solid line is analytical approximation ( [ eq : s_k]).,width=340 ] ( 0,0 ) ( 7,10 ) ( -120,85 ) our numerical calculations show that the starting approximation @xmath132 for vertex function and the solution @xmath120 of the scba equation ( [ eq : sigmaexact ] ) are very close to each other . therefore , to obtain analytical approximation for the nonlocal spin density we substitute ( [ eq : gamma_0 ] ) in eq . ( [ eq : s_nloc_zg ] ) and use formula ( [ eq : g_solution_scba ] ) for the impurity s green s function , the result reads @xmath133 here @xmath134 is macdonald function of the first kind . at distances @xmath135 using expansion of the macdonald function @xmath136 at @xmath137 , we obtain power - law asymptotics with logarithmic corrections for the spin density : @xmath138 at large distances @xmath139 the spin density ( [ eq : s_k ] ) is exponentially suppressed : @xmath140 . in fig . ( [ figspindistr ] ) solid lines correspond to the analytical result given by eq . ( [ eq : s_k ] ) . one can see excellent agreement between the analytical and the numerical results . the net spin of the system , which is given by the sum of local impurity spin and spin of nonlocal cloud is conserved and must be equal to @xmath7 . the integral spin , corresponding to the nonlocal spin density @xmath141 is plotted in fig . [ figspintot ] versus @xmath142 . and local spin of the imputity @xmath143 as a function of the magnon gap @xmath94 in scba . full and open markers correspond to values of effective coupling constant @xmath104 and @xmath144 . circles correspond to @xmath145 , squares represent @xmath143 and triangles show the net spin @xmath146 . solid lines are theoretical predictions for the local impurity spin @xmath143 , given by eq . ( [ eq : s_imp_scba ] ) . dotted lines are visual guides for @xmath145 . red dashed line corresponds to the net spin equal to @xmath5.,width=340 ] ( 0,0 ) ( 0,10 ) ( -120,85 ) we use the numerical results for @xmath119 , shown in fig . [ figspindistr ] , in order to obtain @xmath145 . one can see that the nonlocal spin @xmath145 logarithmically increases with decreasing @xmath94 and tends to @xmath147 at the critical point . therefore the rest of the spin should be attributed to the impurity spin @xmath148 , which vanishes at the qcp . we check this statement in section [ sec : spin_impurity ] , calculating local spin of the impurity . to calculate impurity spin , localized at @xmath149 , we use similar approach to that we used in the previous section . we introduce local magnetic field @xmath150 and calculate energy shift of the impurity due to the magnetic field . the result for the impurity spin reads @xmath151 diagrammatic equation for the vertex function @xmath152 in scba has the graphical representation , shown in fig . [ fig : gamma_eps ] . . cross represents bare vertex @xmath153.,width=226 ] ( 0,0 ) ( -168,12 ) ( -134,12 ) ( -101,12 ) ( -51,12 ) corresponding analytical form of the equation represented in fig . [ fig : gamma_eps ] is @xmath154 solving equation ( [ eq : gamma_eps ] ) and substituting the solution in to eq . ( [ eq : s_imp ] ) we obtain with logarithmic accuracy spin of the impurity @xmath155 we also calculate residue spin of the impurity numerically , solving iteratively eg . ( [ eq : gamma_eps ] ) . both analytical and numerical results for @xmath143 at different values of the parameters @xmath94 and @xmath37 are plotted in fig . [ figspintot ] . we see good agreement between the analytical and the numerical results . from fig . [ figspintot ] we can notice that the impurity spin logarithmically tends to zero when we approach to the qcp , @xmath156 . in fig . [ figspintot ] we also show the net spin @xmath157 for different values of @xmath94 and @xmath37 . results of our calculations , presented in eq . ( [ eq : asympt_small_scba ] ) , eq . ( [ eq : s_imp_scba ] ) and also in figs . [ figspindistr ] , [ figspintot ] show that at the qcp the local spin is approaching to zero and the spin of the system is accumulated in the nonlocal spin cloud . this delocalized spin cloud around impurity has size proportional to inverse magnon gap @xmath158 , and therefore significant part of impurity spin is separated from charge , localized at @xmath3 . we will return to this discussion again in the section [ sec : rg_s(r ) ] . the net spin of the system equals to @xmath5 . this is an exact statement and can be demonstrated at the diagrammatic level . one can trace mutual cancellations of corrections to the impurity spin and integral spin of nonlocal cloud in every order in @xmath37 . corrections to the impurity spin @xmath143 are cancelled by corrections to integral spin @xmath145 . the numerical results for the net spin of the system presented in fig . [ figspintot ] , are consistent with the conservation of spin . using eq . ( [ eq : phi_def ] ) and eq . ( [ eq : s_imp_scba ] ) we obtain following expression for the staggered magnetization induced by the spin @xmath5 impurity @xmath159 away from the qcp the staggered magnetization , induced by the impurity is exponentially small . in the vicinity of the qcp prefactor in eq . ( [ eq : phi_scba ] ) becomes logarithmically suppressed , however the staggered magnetization decays only as @xmath54 . in this section we calculate nonlocal and local components of the spin density using rg technique in @xmath6 dimensions . in the rg approach the coupling constant @xmath37 becomes dependent on the energy scale . since @xmath6 d is the upper critical dimension , the evolution of the running coupling constant is logarithmic . it leads to logarithmic corrections to @xmath160 and @xmath161 , similar to results ( [ eq : asympt_small_scba ] ) and ( [ eq : phi_scba ] ) obtained in scba . we derive our results for the case of an arbitrary spin @xmath0 of the impurity in sections [ sec : rg_coupl_z ] and [ sec : rg_s(r ) ] , and then we analyze the limit of a large spin @xmath0 in section [ sec : rg_s ] . in rg technique we consider evolution of the coupling constant @xmath37 , quasiparticle residue @xmath121 , spin density and staggered magnetization with the energy scale @xmath162 , starting evolution from the ultraviolet scale @xmath30 and finishing at the infrared scale @xmath94 . the scale @xmath162 here has the meaning of the characteristic energy transfer from magnons to the impurity . at ultraviolet scale @xmath30 we set parameters of the theory to bare values , in our calculations @xmath30 plays a role of a renormalization point . observables in the vicinity of the qcp are calculated as the result of rg evolution from the ultraviolet scale @xmath30 to the infrared scale @xmath163 . first , we calculate evolution of the coupling constant @xmath164 . one - loop correction to the coupling constant is represented by the sum of diagrams , shown in fig . [ fig : vertex_rg ] . ( 0,0 ) ( -180,15 ) ( -115,15 ) ( -55,15 ) ( -140,0 ) ( -80,0 ) ( -20 , 0 ) note , that in rg approach the correction to the coupling constant includes the vertex correction [ fig . [ fig : vertex_rg ] , ( b ) ] , and also the self - energy correction [ fig . [ fig : vertex_rg ] , ( c ) ] . this is different from scba , in which we disregard diagram ( b ) . contribution @xmath165 to the coupling constant correction is given by the diagram ( b ) in fig . [ fig : vertex_rg ] and reads @xmath166 after cancelling out the factor @xmath167 from the both sides of eq . ( [ eq : delta_coupl_1 ] ) we obtain @xmath165 . the second contribution @xmath168 , which comes from the diagram ( c ) in fig . [ fig : vertex_rg ] reads @xmath169 and contains linear in @xmath30 and logarithmic in @xmath30 terms . the linear term corresponds to the shift of the position of quasiparticle pole @xmath170 in the impurity s green s function and therefore is irrelevant for our purposes . the logarithmic term in @xmath171 reads @xmath172 total correction to the coupling constant @xmath37 is @xmath173 note , that for @xmath7 the vertex correction ( [ eq : delta_coupl_1 ] ) is suppressed by the factor @xmath174 , comparing to @xmath168 . this suppression corresponds to standard @xmath75 expansion of @xmath100 group . however , at large @xmath0 the @xmath75 suppression of @xmath165 is compensated by @xmath0 , and hence @xmath165 and @xmath168 to a large extent compensate each other , @xmath175 . thus , at large @xmath0 the vertex correction becomes significant and can not be disregarded . this is the reason why scba fails in the case of large impurity spin . in the paradigm of rg , evolution of physical parameters on some energy scale @xmath162 is determined by the value of @xmath164 on the same scale . hence , eq . ( [ eq : d_lambda_12 ] ) results in the following gellman - low equation @xmath176 solution to eq . ( [ eq : d_ln_alpha ] ) with the initial condition @xmath177 is @xmath178 note , that the running coupling constant ( [ eq : alpha_rg_solut ] ) vanishes in infrared limit : @xmath179 at @xmath180 . the rg scale @xmath162 is bounded from below by the value of magnon gap @xmath181 . in order to find the quasiparticle residue of the impurity s green s function we consider one - loop correction to the impurity s self - energy . logarithmic part of this correction was already calculated as a part of the diagram ( c ) in fig . [ fig : vertex_rg ] . corresponding equation for evolution of @xmath182 reads @xmath183 solution to eq . ( [ eq : d_ln_z ] ) with initial condition @xmath184 reads @xmath185 the quasiparticle residue @xmath182 vanishes , while approaching to the qcp : @xmath186 . note , that rg approach , being used in the current section , is valid if the effective coupling constant @xmath187 , since we perform perturbative expansion , such as in eq . ( [ eq : d_lambda_12 ] ) . however , the proper expansion parameter in the vicinity of the qcp is not @xmath188 , but @xmath189 . rg method ( in single - loop approximation ) allows to sum up ( leading ) logarithmic corrections of the following kind @xmath190 . therefore , the results obtained within one - loop rg in the section [ sec : rg ] are valid when @xmath191 and @xmath192 , but the product @xmath193 can have an arbitrary value . now we consider rg evolution of the impurity spin @xmath143 and spin density distribution @xmath74 with renormalization scale @xmath162 . as in section [ sec : magnon_spin ] we calculate @xmath143 and @xmath74 , considering interaction of the system with probe magnetic field @xmath194 . we start from calculation of corrections to @xmath143 due to interaction of the impurity with magnons . one - loop corrections to @xmath143 are shown in fig . [ fig : vertex_xi_rg ] . ( -180,15 ) ( -115,15 ) ( -55,15 ) ( -135,0 ) ( -75,0 ) ( -15 , 0 ) note , that the diagrams in fig . [ fig : vertex_xi_rg ] are analogous to the diagrams in fig . [ fig : vertex_rg ] for corrections to the coupling constant @xmath37 . the only difference is that the impurity - magnetic field coupling @xmath195 is proportional to the impurity spin @xmath50 . hence , rg evolution equation reads @xmath196 solution to eq . ( [ eq : d_ln_xi ] ) with initial condition @xmath197 is following @xmath198 and proportional to solution ( [ eq : alpha_rg_solut ] ) for running coupling @xmath164 . the local spin at the impurity site is equal to @xmath199 and approaches to zero at the qcp . using the result ( [ eq : s_imp_rg ] ) and relation ( [ eq : phi_def ] ) we obtain distribution of staggered magnetization around impurity @xmath200 now we calculate the nonlocal spin density @xmath119 . in rg technique it is more natural to use momentum representation for the spin density , therefore we write evolution equation for the fourier component @xmath201 . leading in @xmath202 contribution to @xmath201 is provided by one - loop diagram , shown in fig . [ fig : gamma ] , ( b ) . evaluation of this diagram with logarithmic precision leads to @xmath203 fourier transform of the second line of eq . ( [ eq : s_0_rg ] ) gives the spin density @xmath204 at the distances @xmath205 . in analogy with the result ( [ eq : asympt_small_scba ] ) , obtained in scba , in rg calculations , we should expect logarithmic corrections to @xmath1 distribution . note , that the logarithmic corrections are important , because they provide proper normalization condition of the integral nonlocal spin @xmath206 at the qcp . volume integral of the spin density @xmath1 is logarithmically divergent @xmath207 if we disregard the log corrections . in order to account for rg evolution of the spin - density , we evaluate single - loop corrections to the leading diagram presented in fig . [ fig : gamma ] , ( b ) . diagrams ( b ) and ( c ) in fig . [ fig : vertex_o_rg ] represent these corrections , which are similar to corresponding diagrams in figs . [ fig : vertex_rg ] and [ fig : vertex_xi_rg ] . ( -185,55 ) ( -115,55 ) ( -55,55 ) ( -185,15 ) ( -140,40 ) ( -80,40 ) ( -20 , 40 ) rg evolution of nonlocal spin density distribution reads @xmath208 note , that equation for evolution of the spin density with @xmath162 is different in two domains @xmath209 and @xmath210 , which is due to the fact , that one - loop expression ( [ eq : s_0_rg ] ) for spin density has various form in the both domains . we solve eq . ( [ eq : d_ln_s(q ) ] ) separately in the two domains and match the solutions at @xmath211 . as an initial condition for the evolution equation ( [ eq : d_ln_s(q ) ] ) we set @xmath212 . we obtain following result for the spin density at infrared scale @xmath213 : @xmath214 condition of the net spin conservation in the momentum representation has the form @xmath215 . using expressions ( [ eq : s_imp_rg ] ) and ( [ eq : s(q)_rg ] ) it is easy to check the net spin conservation , having in mind that the low bound for the momentum @xmath216 in our formulas is @xmath217 . calculating fourier transform of eq . ( [ eq : s(q)_rg ] ) we obtain spatial distribution of the induced spin density @xmath218 at the distances @xmath219 . using ( [ eq : s(r)_rg ] ) and ( [ eq : s_imp_rg ] ) one can verify conservation of the net spin in @xmath124-representation : @xmath220 . integration of nonlocal spin density should be performed in the range of the distances @xmath221 which is defined by the infrared and ultraviolet cutoffs for our theory . note , that at the qcp the main contribution to the nonlocal spin @xmath222 comes from large distances @xmath223 . indeed , the integral @xmath224 logarithmically grows as a function of the upper integration limit @xmath225 , which means that major part of spin in the nonlocal cloud is accumulated at the distances of the order of @xmath226 . at the same time , the local spin of the impurity @xmath143 vanishes at the qcp , see eq . ( [ eq : s_imp_rg ] ) . therefore , we conclude that at the qcp the impurity s spin is spatially separated from the impurity charge . the results ( [ eq : z_rg_solut ] ) , ( [ eq : phi_rg ] ) and ( [ eq : s(r)_rg ] ) obtained in rg technique are similar to corresponding answers ( [ eq : z_scba ] ) , ( [ eq : phi_scba ] ) and ( [ eq : asympt_small_scba ] ) , obtained in scba . for the spin @xmath7 the difference is in the numerical factors in front of the logarithms : @xmath227 in scba , comparing to @xmath228 in rg . for @xmath121 and @xmath229 the powers of logarithms are also insignificantly changed : @xmath230 and @xmath231 , respectively . the reason for this minor changes is due to the @xmath75 vertex correction , which is accounted in rg approach ( see diagram ( b ) in fig . [ fig : vertex_rg ] ) , and is disregarded in scba . the rg results are more accurate , then scba results . however , the expansion of the rg results and scba results coincide up to the single - loop order ( first order in @xmath202 ) . from theoretical point of view it is interesting to consider the semiclassical case of large spin of the impurity . taking formal limit @xmath232 in eqs . ( [ eq : s_imp_rg ] ) , ( [ eq : phi_rg ] ) and ( [ eq : s(r)_rg ] ) we obtain @xmath233 we see from eq . ( [ eq : large_spin ] ) , that in the semiclassical limit there is no nonlocal spin density around impurity and local spin @xmath0 is `` unscreened '' in this case . therefore , there is no spin - charge separation in the semiclassical limit . note , that local impurity spin , nonlocal spin density and staggered magnetization in the semiclassical limit are provided just by tree - level approximation . the reason is that quantum fluctuations of the of impurity spin are suppressed at large @xmath0 . indeed , let us consider the case of impurity in the state with maximal projection of spin on the quantization axis @xmath234 : @xmath235 . interaction of the impurity with magnon either leaves projection @xmath236 to be unchanged or changes it by unity , @xmath237 . the action of operator @xmath238 on the state @xmath239 provides eigenvalue @xmath0 . on the other hand , matrix element of the lowering operator @xmath240 between states @xmath241 and @xmath239 is equal to @xmath242 . therefore , the processes with change of projection of the impurity spin are suppressed in the limit of large @xmath0 . in the semiclassical limit only @xmath234-component of the operator of impurity spin is relevant , as a result the lagrangian in eq . ( [ initlagrangianint ] ) , corresponding to interaction of the impurity with magnons takes the form @xmath243 thus , the problem of classical impurity `` dressed '' with @xmath234-polarized magnons is equivalent to the problem of impurity interacting with scalar bosonic field @xmath244 . the problem of interaction between impurity and scalar boson field is known as independent boson model , this model is exactly solvable.@xcite the exact solution agrees with eq . ( [ eq : large_spin ] ) . retarded green s function of the impurity in time representation at @xmath245 reads @xcite @xmath246,\ ] ] where @xmath247 . performing fourier transformation of the impurity green s function ( [ eq : g_mahan ] ) , and calculating quasiparticle residue at the green s function pole @xmath248 , we obtain @xmath249 in the limit @xmath250 the rg result ( [ eq : z_rg_solut ] ) is consistent with eq . ( [ eq : large_spin_z ] ) . in the present paper we have considered a single impurity with spin s embedded into 3d af system , which is close to the @xmath28 quantum critical point ( qcp ) , separating paramagnetic and neel magnetic phases . the impurity spin induces the usual magnetization and the staggered magnetization clouds around position of the impurity . using the effective lagrangian method and approaching the qcp from the disordered phase , we have calculated spatial distributions of the spin density @xmath74 ( magnetization ) and the staggered magnetization @xmath161 in the cloud . for calculations we use two different methods , self consistent born approximation ( scba ) and renormalization group ( rg ) . scba is justified by the small parameter @xmath75 where @xmath27 for the @xmath28 group , while rg is justified by the small coupling constant . we show that for @xmath7 results of both methods are consistent within expected accuracy @xmath75 . however , at larger values of the impurity spin the scba method is not valid because the small parameter @xmath75 is compensated by the large spin . therefore , for @xmath251 only rg results are valid . the impurity quasiparticle residue vanishes at the qcp , see eq . ( [ eq : z_rg_solut ] ) . this is the first indication , that the impurity spin is fully transferred to the magnon cloud . the effect of screening of impurity s spin by spin - one magnetic fluctuations is a kondo effect in a bosonic sector . @xcite the spin density has a local component @xmath252 , which is localized at the site of the impurity , as well as a spatially distributed nonlocal part @xmath119 . because of the vanishing residue the average impurity spin @xmath143 logarithmically vanishes at the qcp , see eq . ( [ eq : z_rg_solut ] ) . of course , the total spin @xmath0 is conserved and it is transferred into the nonlocal spin cloud . the nonlocal spin density at @xmath253 , where @xmath94 is the magnon gap , decays as @xmath254 with proper logarithmic corrections , see eq . ( [ eq : s(r)_rg ] ) . obviously , at @xmath255 the spin density decays exponentially . integral spin in the nonlocal spin cloud is mainly accumulated at large distances @xmath256 , see eq . ( [ eq : rg_integral_spin ] ) . therefore the spin is spatially separated from the impurity and at @xmath257 the separation scale becomes infinite . in this sense our results demonstrate the spin - charge separation in 3d magnetic systems at the qcp . interestingly , the cloud of the staggered magnetization at @xmath253 decays only as the first power of distance , see eq . ( [ eq : phi_rg ] ) . this is why a tiny concentration of impurities can significantly influence the critical behaviour of the system . finally , we have analyzed the semiclassical limit of a very large impurity spin , @xmath258 . in this limit the quantum spin - flip transitions become negligible and the spin impurity problem is reduced to an exactly solvable textbook example . @xcite a. oosawa , m. fujisawa , k. kakurai , and h. tanaka , phys . b * 67 * , 184424 ( 2003 ) . h. imamura , t. ono , k. goto , and h. tanaka , phys . b * 74 * , 064423 ( 2006 ) . t. suzuki , i. watanabe , f. yamada , y. ishii , k. ohishi , risdiana , t. goto , and h. tanaka , phys . b * 80 * , 064407 ( 2009 ) .

we consider a single impurity with spin @xmath0 embedded in a three - dimensional antiferromagnetic system which is close to the quantum critical point ( qcp ) , separating magnetically ordered and disordered phases . approaching the qcp from the disordered phase we study the spatial distribution of spin density and staggered magnetization induced by the impurity . using two methods ( self - consistent born approximation and renormalization group ) we found a power law decay of the spin density @xmath1 , and of the staggered magnetization @xmath2 with relevant logarithmic corrections . we demonstrate that the local spin at the impurity site @xmath3 approaches to zero at the qcp . we show that in the semiclassical limit of large @xmath0 the problem is equivalent to the exactly solvable independent boson model . our results demonstrate existence of spin - charge separation in the three dimensional systems in the vicinity of the qcp .

the cosmic - ray spectrum extends from the sub - gev region to at least @xmath0 gev ( fig . [ fig1 ] . ) up to @xmath1 gev and somewhat higher , measurements with magnetic spectrometers flown above most of the atmosphere provide good momentum resolution along with identification of the charge and mass of individual primaries . measurements with calorimeters continue to identify individual primaries to beyond @xmath1 tev , but with larger systematic uncertainties in the energy assignment . in the pev region and beyond , the cosmic - ray intensity is too low for direct measurements ; only indirect measurements of air showers from the ground are possible . since the particles are not identified on an event - by - event basis , the energy spectrum derived from measurements of air showers is given as an all - particle " spectrum , in terms of energy per particle rather than energy per nucleon . in the air - shower regime , identification of the primary mass is made in one of several indirect ways on a statistical basis , complicating the search for features in spectra of individual elements . the gyroradius of a proton in a typical galactic magnetic field of 3 @xmath2gauss is about half a parsec at one pev . the parsec scale is also typical of the size of structures in the interstellar medium driven by supernova explosions . for particles with higher energy and larger gyroradii , diffusion in the interstellar medium may become less efficient . estimates of the maximum energy of particles accelerated at supernova shocks are around the same energy . it is therefore natural to guess that the knee of the cosmic - ray spectrum around 3 pev has something to do with the end ( or at least the beginning of the end ) of the galactic cosmic - ray spectrum . peters @xcite described the consequences for energy dependence of the primary composition if the spectrum is characterized by a maximum rigidity , @xmath3 , which could be associated either with propagation or with acceleration ( or both ) . the relation between rigidity and total energy is @xmath4 where @xmath5 is the total energy of a nucleus of charge @xmath6 and mass @xmath7 . if cosmic rays are classified by energy per particle , as is the case for air shower measurements , then the spectrum should steepen first for protons , then for helium , then for the the cno group etc . elsewhere @xcite i have called this sequence the `` peters cycle '' . several air shower measurements show some evidence that the spectrum becomes progressively enriched in heavy nuclei through the knee region . the clearest evidence for the peters sequence for several groups of nuclei comes from analysis of the kascade experiment @xcite . data from direct measurements above 100 tev are sparse , leaving a gap that is bridged by emulsion chamber data with low statistics below a pev and by the threshold region of air shower experiments above 100 tev . apart from the technical problems of low statistics and systematic threshold effects , there is also the problem that air shower experiments do not identify individual primary nuclei . in addition , the efficiency of ground arrays depends strongly on primary mass in the threshold region . nevertheless , it is possible to form a fairly consistent picture of the cosmic - ray spectrum up to the knee . and by @xmath8 for clarity ( see text ) . , title="fig:",width=264 ] and by @xmath8 for clarity ( see text ) . , title="fig:",width=264 ] figure [ fig2 ] shows several measurements of the primary spectrum through the knee region . up to 100 gev there are good measurements of the spectra of protons and helium with magnetic spectrometers flown in spacecraft @xcite and high - altitude balloons @xcite . using the ams @xcite and bess @xcite measurements , together with measurements of heavier nuclei at @xmath9 gev / nucleon @xcite , i have converted the spectra of protons , helium , cno , ne - si and fe from energy per nucleon to total energy per particle and combined them to give the all particle spectrum at low energy ( shown as the solid line in fig . [ fig2 ] ) . the highest energy direct measurements in which individual nuclei are identified directly are from emulsion chamber experiments . measurements of protons and helium from runjob @xcite and jacee @xcite are shown in fig . preliminary data on protons and helium from the atic thin ionization chamber @xcite ( not shown here ) are consistent with a smooth power - law extrapolaton between the bess and ams spectromter data at low energy and the runjob data above @xmath9 tev . ( the jacee helium data are higher . ) the solid line normalized to the all - particle spectrum at 100 gev and extrapolated to 1 pev with an @xmath10 power law is consistent with the all - particle measurements of grigorov @xcite but about a factor 1.5 above the sum of the runjob spectra at 100 tev . ( using the higher jacee measurement of helium would bring the emulsion chamber measurements into agreement with the @xmath10 extrapolation at 100 tev . ) an external motivation for using the hard extrapolation from the spectrometer measurements comes from the super - k measurement of the flux of atmospheric neutrinos , where the best fit to the data requires an even harder extrapolation of the primary spectrum above 100 gev @xcite . even with the hard @xmath10 spectrum , the extrapolation of the direct measurements comes in somewhat below the air shower measurements . moreover , the all - particle spectrum of runjob @xcite is somewhat below the lowest - energy air shower data , so there may be some systematic offset between the direct measurements and the measurements of air showers . there is also a slight correlation between hardness of the fitted spectrum and primary mass in this energy range @xcite . there is , however , no sign @xcite of the sharp steepening of the proton spectrum , below @xmath1 tev , which would be the case if the maximum rigidity accessible in most galactic cosmic - ray accelerators were around @xmath1 tv or below as originally estimated for diffusive shock acceleration by expanding supernova remnants @xcite . although there are systematic differences among the various air shower measurements in the knee region , all show that the spectrum steepens from @xmath11 or slightly harder below @xmath12 pev to @xmath13 above @xmath9 pev . figure [ fig2]b shows several results . two of the measurements @xcite show evidence of structure in the knee region , while the others @xcite do not . the figure also shows the spectra of two of the measurements ( casa - mia and tibet ) with the energy assignments of the latter shifted down by a factor of @xmath14 , which may be taken as an indication of systematic uncertainties in energy assignment . the shapes of these two spectra agree well with each other . some authors @xcite have suggested that a single source contributes significantly to the flux of cosmic - rays in the knee region . the possible offset between the air - shower measurements and the extrapolation of the direct measurements leaves room for such a possibility . others @xcite argue , however , that the overall smoothness of the spectrum indicates a single population , with a secondary acceleration mechanism boosting some of the cosmic rays accelerated by galactic supernova explosions to higher energy . several authors @xcite approach the problem from the high - energy end by modelling the highest energy spectrum as arising from a cosmological distribution of sources and subtracting the extra - galactic population from a model of the supernova - accelerated population to see if an extra , high - energy galactic source is required to fill in the energy region above the knee ( population b " @xcite ) . this is an open question at present . ( for a recent review and further references see @xcite . ) in any case it is interesting to estimate the power required to produce the high - energy end of the galactic cosmic - ray spectrum . to do so , i assume a model of galactic propagation with diffusion characterized by an equivalent leaky box model with a escape time given by @xmath15 which applies for all energies . with this propagation model ( motivated by lack of anisotropy at high enery ) , the source spectrum at low energy must be @xmath16 to give the observed @xmath10 spectrum inside the galaxy . assuming a maximum rigidity of @xmath12 pv for this low - energy component , with a composition as measured by an emulsion chamber experiment @xcite , the assumed low - energy component can be subtracted from the observed spectrum . the total power required to account for the observed spectrum up to @xmath12 eev is then @xmath17 erg / sec . such an estimate is obviousy very model dependent , but not unreasonably large compared to what might be available in individual galactic sources . what is needed to make progress is a precise knowledge of the energy - dependence of the major groups of nuclei ( p , he , cno , heavy ) through the knee region . if there are several important groups of sources with different maximum rigidities then there should be a corresponding sequence of peters cycles , perhaps characterized by different compositions . the transition to extra - galactic cosmic - rays would be characterized by a transition from heavy nuclei ( from the highest galactic source ) to the light component of a cosmological distribution of sources . a recent summary of composition measurements with air showers in the knee region is given in the rapporteur paper of matthews at the last icrc @xcite ( see also swordy _ et al . _ overall , the evidence suggests a change in composition toward hearvier primares at higher energy as expected . however , results of different measurements disagree in detail and the picture is not very clear . as noted in the introduction , the best evidence for the sequence of increasingly heavier groups of nuclei comes from the kascade experiment @xcite , which uses the ratio of muons to electrons as a probe of primary composition . ratio of muons to electrons in the shower front is a classic probe of primary composition . at each interaction of the nucleons in an air shower , roughly 1/3 of the energy not retained by the projectile nucleon is transferred to the electromagnetic component of the cascade via @xmath18 and 2/3 to charged pions . the charged pions either reinteract or decay depending on their energy and the depth ( and hence the density ) in the atmosphere where they are produced . charged pions that interact contribute further to the electromagnetic component while those that decay feed the muon component of the air shower . comparing nuclei of the same total energy , charged pions reach the energy at which they can decay earlier in the cascade for heavy primaries than for protons because the initial energy per nucleon is lower by @xmath19 . as a consequence , the ratio of the muonic to the electromagnetic component of an air shower is larger for heavy primaries . to measure this ratio with greatest sensitivity requires an observation near shower maximum so that the size of the shower is well correlated with the primary energy . in general , showers in the knee region and somewhat above are observed after shower maximum so that fluctuations in the relation between observed shower size and primary energy are important . kascade is a surface array near sea level so that these fluctuations are large . muons detected in kascade typically have energies of a few gev . an alternative , realized with eastop - macro @xcite and with spase - amanda @xcite , is to sample the muon component with a deep underground detector and the electromagnetic component with an array on the surface above . such a setup selects muons with sufficiently high energy at production to penetrate to the deep detector . the high - energy muons generally come more from the fragmentation region of phase space of the hadronic interactions in the shower , whereas than the low - energy muons reflect more the less well - understood central region . on the other hand , the multiplicity of high - energy muons is small so that fluctuations in muon number are more important . some of these points are illustrated in fig . [ fig3 ] which compares @xmath20 vs. @xmath21 for high - energy ( @xmath22 tev ) muons and for low - energy muons in @xmath23 and @xmath24 ev showers simulated with corsika . in general , the mass resolution is somewhat better for the low energy muons provided that the sampling is good enough to get a good measure of the muon number in individual showers , while the energy resolution is better for coincident events with high energy muons , particularly if the surface array is at high altitude . this complementarity was pointed out by ralph engel @xcite . it is interesting that analyses of both eastop - macro @xcite and spase - amanda @xcite suggest an increase in the mean primary mass in the decade of energy above a pev , that is , through the knee region . as a muon detector , macro has the advantage of resolving muon tracks , whereas amanda reconstructs the light pool generated by the bundle , which gives a measure of the energy deposition of the muons . a limitation of both experiments is the relatively small sampling area of the deep muon detectors , which has to be accounted for in the comparison between data and simulations . icecube , with its surface component icetop , now under construction at the south pole @xcite will have a much larger acceptance . engineering data from the first year of operation of icecube with four icetop stations and one string demonstrate the ability of icecube to reconstruct events with few nanosecond accuracy over distances of more than two kilometers @xcite . since january 2006 icecube has been operating with 16 surface stations and 9 strings of detectors in the ice . each string contains 60 digital optical modules ( doms ) evenly spaced in the clear ice between 1450 and 2450 meters below the surface . each icetop station consists of two ice cherenkov tanks separate from each other by 10 meters and located 25 m from the top of the corresponding icecube string . each tank is instrumented with two of the same doms used in the ice . with a nominal grid spacing of @xmath25 m , the acceptance of the current partial array is @xmath26 m@xmath27sr , which allows detection of coincident events approaching @xmath28 ev . the acceptance of the full icecube as a three - dimensional air shower array will be approximately @xmath29 km@xmath27sr , allowing measurement of coincident events up to an eev . it is scheduled for completion in 2011 and will be operating in the meantime as new detectors are added . analysis of measurements of energy - dependence of the depth of shower maximum with hires @xcite suggest a change in composition from heavy to light as energy increases from @xmath28 to @xmath30 ev . shower maximum is deeper in the atmosphere for protons than for heavy nuclei of the same total energy . the measured depth of shower maximum increases more rapidly than expected from model calculations , indicating an increasing fraction of protons as energy increases . a similar change was observed in analysis of the fly s eye data @xcite but at a higher energy ( above @xmath30 ev ) . it was recognized at the time that such a change of composition could be a signature of the transition from a population of galactic cosmic rays to an extra - galactic population . in view of the more recent data , the signature of a transition appears to occur at a lower energy ( below @xmath30 ev ) . a discussion and references to cosmological scenarios in which the transition to extra - galactic cosmic rays occurs at relatively low energy is given by hillas @xcite . several new experiments are planned or in operation that can explore the energy region from the knee to the eev region to overlap with the threshold region of the giant arrays auger @xcite and ( formerly ) agasa @xcite . the most advanced of these if kascade - grande @xcite , a large sea - level array that includes the original kascade as a subarray . icecube is under construction as described in telescope array @xcite and its low - energy extension , tale @xcite , are under development in utah . there is a propsed array of atmospheric cherenkov detectors , tunka @xcite , in russia , and use of the radio technique for a large acceptance air shower detector is being explored @xcite . understanding the transition from a galactic to an extra - galactic population of cosmic rays is an interesting and important goal for the near future . * acknowledgments * i thank peter niessen for the generating the data for fig . 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several kinds of measurements are combined in an attempt to obtain a consistent estimate of the spectrum and composition of the primary cosmic radiation through the knee region . assuming that the knee is a signal of the high - energy end of a galactic cosmic - ray population , i discuss possible signatures of a transition to an extra - galactic population and how they might be detected .

Open-Access Journals Hit By Journalist's Sting Although many open-access scientific journals claim the articles they publish are subject to peer review, that doesn't always happen. Science magazine contributor John Bohannon sent out bogus papers about a fictitious cancer experiment, papers that should have raised red flags. But more than 150 journals offered to publish his work. Bohannon talks to Renee Montagne about the implications of his sting operation. DAVID GREENE, HOST: This is MORNING EDITION from NPR News. Good morning, I'm David Greene. RENEE MONTAGNE, HOST: And I'm Renee Montagne. Publication is the coin of the realm for scientists. It's how they make their careers. GREENE: Traditionally, it's been hard to get research published at least until the last decade and explosion of open-access journals online. MONTAGNE: Unlike Nature or the Journal of the American Medical Association, open access journals don't charge readers. Instead, they may charge the researchers they publish - sometimes thousands of dollars. GREENE: And there's another important difference. Often open-access journals don't do what's known as peer review. MONTAGNE: Reporter John Bohannon, of Science magazine, found out just casual the vetting process can be with Web journals, compared to how it's long been with peer-reviewed journals. JOHN BOHANNON: The basic idea is if you're a general editor, a paper submission comes in. First, you do a smell test and as long as it looks reasonable, and has the potential to be important enough or interesting enough to be published in your journal, then you send it out to peer reviewers - which are at least one, sometimes as many as five or six independent scientists, and they remain anonymous. And those scientists go to town on that paper. They try and find anything that could be wrong with it. They nitpick wording. They question the underlying assumptions. And they send all this feedback to the editor, who then sends it on to the scientist anonymously. And it's a back-and-forth. The results, everyone agrees, is that papers come out better because of it. MONTAGNE: Right, so given the rise of open-access journals, you decided to do an experiment. That is, send in for publication a fake experiment. And, as you describe it, it is a sting operation. BOHANNON: That's right. So I created a paper that purportedly tests the effect of a chemical on cancer cells. And that chemical was extracted from a lichen; one of those scrubby, moss- like, little things that grow on rocks. And then I created a computer program to scale this up. So I created hundreds of very similar but fake papers from fake African scientists. MONTAGNE: And then, the key to all of this is that you wrote what amounted to a hopelessly flawed experiment. BOHANNON: That's right. It was a paper which was credible. It looked like real paper, not a joke. But if you peer-reviewed it, you would within five minutes see that it was so flawed that it could never be published. MONTAGNE: Tell me one red flag. BOHANNON: OK, if you're claiming to have evidence that some chemical is a promising new drug, well, you better have tested at least on healthy cells. Because even if you show that it hurts cancer cells, how do you know what you have there isn't just a poison? So that's one thing that's just awful about the paper, is that it doesn't compare cancer cells to healthy cells at all. But another one is right there in the first data graph, shows this chemical being tested on cancer cells across a huge range of concentrations. And that every single one of those doses, it has the same moderate effect on the cancer cells. And the graph claims to show a dose-dependent effect. Now, any real scientist who's reading it as a peer reviewer will say, hang on, that is the opposite of the dose-dependent effect. MONTAGNE: And you turned it into how many journals? And how many approved it and were going to publish it? BOHANNON: I submitted it to over 300 journals. And, in fact, just this morning - an hour before we're talking - one more acceptance rolled in. MONTAGNE: And that brought your number of acceptance to what? BOHANNON: One hundred and fifty-eight acceptances versus 98 rejections. MONTAGNE: We should say that the journal where you work, Science, does do peer review. These open-access journals also say they do peer review, but what you're finding is that some don't - or at least some don't do it well. What is the take away? BOHANNON: The take away shouldn't be that open-access is broken and not worth trying. Open-access is great and everyone believes that. It's just a question of how to implement it. I mean, there were a lot of bad journals revealed by this experiment. But on the other hand, there were a lot of good ones. I was so happy, for example, to get the rejection letter from a Hindawi journal. Hindawi is this huge operation in Cairo, and has been criticized for being low quality and spamming scientists. And yet they provided great peer review. MONTAGNE: Also, researchers who submit their work are not necessarily scammers. Some would really benefit from valuable peer review and they're not getting it, which is quite unfair in that respect. BOHANNON: That's right. Yeah absolutely, some of the victims here are surely the scientists who have paid good money to have their work peer-reviewed and published in these journals. Many of them, probably naively, think that they're taking part in a scientific enterprise and, in fact, they're just getting duped. But my hope is that now that we have a map of at least some of the good versus bad journals, scientists can submit their papers to one of the good guys and for the same amount of money, get the real deal. MONTAGNE: Thank you very much for joining us. BOHANNON: Thank you, Renee. MONTAGNE: John Bohannon is a molecular biologist and visiting researcher at Harvard University. He's also a correspondent for "Science" magazine. And his article, "Who's Afraid of Peer Review, " is in the current issue. Copyright © 2013 NPR. All rights reserved. Visit our website terms of use and permissions pages at www.npr.org for further information. NPR transcripts are created on a rush deadline by Verb8tm, Inc., an NPR contractor, and produced using a proprietary transcription process developed with NPR. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record. ||||| Science Vol. 342 no. 6154 pp. 60-65 DOI: 10.1126/science.342.6154.60 Who's Afraid of Peer Review? A spoof paper concocted by Science reveals little or no scrutiny at many open-access journals. On 4 July, good news arrived in the inbox of Ocorrafoo Cobange, a biologist at the Wassee Institute of Medicine in Asmara. It was the official letter of acceptance for a paper he had submitted 2 months earlier to the Journal of Natural Pharmaceuticals, describing the anticancer properties of a chemical that Cobange had extracted from a lichen. In fact, it should have been promptly rejected. Any reviewer with more than a high-school knowledge of chemistry and the ability to understand a basic data plot should have spotted the paper's short-comings immediately. Its experiments are so hopelessly flawed that the results are meaningless. I know because I wrote the paper. Ocorrafoo Cobange does not exist, nor does the Wassee Institute of Medicine. Over the past 10 months, I have submitted 304 versions of the wonder drug paper to open-access journals. More than half of the journals accepted the paper, failing to notice its fatal flaws. Beyond that headline result, the data from this sting operation reveal the contours of an emerging Wild West in academic publishing. From humble and idealistic beginnings a decade ago, open-access scientific journals have mushroomed into a global industry, driven by author publication fees rather than traditional subscriptions. Most of the players are murky. The identity and location of the journals' editors, as well as the financial workings of their publishers, are often purposefully obscured. But Science's investigation casts a powerful light. Internet Protocol (IP) address traces within the raw headers of e-mails sent by journal editors betray their locations. Invoices for publication fees reveal a network of bank accounts based mostly in the developing world. And the acceptances and rejections of the paper provide the first global snapshot of peer review across the open-access scientific enterprise. One might have expected credible peer review at the Journal of Natural Pharmaceuticals. It describes itself as "a peer reviewed journal aiming to communicate high quality research articles, short communications, and reviews in the field of natural products with desired pharmacological activities." The editors and advisory board members are pharmaceutical science professors at universities around the world. The journal is one of more than 270 published by Medknow, a company based in Mumbai, India, and one of the largest open-access publishers. According to Medknow's website, more than 2 million of its articles are downloaded by researchers every month. Medknow was bought for an undisclosed sum in 2011 by Wolters Kluwer, a multinational firm headquartered in the Netherlands and one of the world's leading purveyors of medical information with annual revenues of nearly $5 billion. But the editorial team of the Journal of Natural Pharmaceuticals, headed by Editor-in-Chief Ilkay Orhan, a professor of pharmacy at Eastern Mediterranean University in Gazimagosa, Cyprus, asked the fictional Cobange for only superficial changes to the paper—different reference formats and a longer abstract—before accepting it 51 days later. The paper's scientific content was never mentioned. In an e-mail to Science, managing editor Mueen Ahmed, a professor of pharmacy at King Faisal University in Al-Hasa, Saudi Arabia, states that he will permanently shut down the journal by the end of the year. "I am really sorry for this," he says. Orhan says that for the past 2 years, he had left the journal's operation entirely to staff led by Ahmed. (Ahmed confirms this.) "I should've been more careful," Orhan says. View larger version: Download PowerPoint Slide for Teaching Tangled web. The location of a journal's publisher, editor, and bank account are often continents apart. Explore an interactive version of this map at http://scim.ag/OA-Sting. CREDIT: DAVID QUINN AND DANIEL WIESMANN Acceptance was the norm, not the exception. The paper was accepted by journals hosted by industry titans Sage and Elsevier. The paper was accepted by journals published by prestigious academic institutions such as Kobe University in Japan. It was accepted by scholarly society journals. It was even accepted by journals for which the paper's topic was utterly inappropriate, such as the Journal of Experimental & Clinical Assisted Reproduction. The rejections tell a story of their own. Some open-access journals that have been criticized for poor quality control provided the most rigorous peer review of all. For example, the flagship journal of the Public Library of Science, PLOS ONE, was the only journal that called attention to the paper's potential ethical problems, such as its lack of documentation about the treatment of animals used to generate cells for the experiment. The journal meticulously checked with the fictional authors that this and other prerequisites of a proper scientific study were met before sending it out for review. PLOS ONE rejected the paper 2 weeks later on the basis of its scientific quality. Down the rabbit hole The story begins in July 2012, when the Science editorial staff forwarded to me an e-mail thread from David Roos, a biologist at the University of Pennsylvania. The thread detailed the publication woes of Aline Noutcha, a biologist at the University of Port Harcourt in Nigeria. She had taken part in a research workshop run by Roos in Mali in January last year and had been trying to publish her study of Culex quinquefasciatus, a mosquito that carries West Nile virus and other pathogens. Noutcha had submitted the paper to an open-access journal called Public Health Research. She says that she believed that publication would be free. A colleague at her university had just published a paper for free in another journal from the same publisher: Scientific & Academic Publishing Co. (SAP), whose website does not mention fees. After Noutcha's paper was accepted, she says, she was asked to pay a $150 publication fee: a 50% discount because she is based in Nigeria. Like many developing world scientists, Noutcha does not have a credit card, and international bank transfers are complicated and costly. She eventually convinced a friend in the United States to pay a fee further reduced to $90 on her behalf, and the paper was published. View larger version: Download PowerPoint Slide for Teaching Peer review reviewed. Few journals did substantial review that identified the paper's flaws. CREDIT: C. SMITH/SCIENCE Roos complained that this was part of a trend of deceptive open-access journals "parasitizing the scientific research community." Intrigued, I looked into Scientific & Academic Publishing. According to its website, "SAP serves the world's research and scholarly communities, and aims to be one of the largest publishers for professional and scholarly societies." Its list includes nearly 200 journals, and I randomly chose one for a closer look. The American Journal of Polymer Science describes itself as "a continuous forum for the dissemination of thoroughly peer-reviewed, fundamental, international research into the preparation and properties of macromolecules." Plugging the text into an Internet search engine, I quickly found that portions had been cut and pasted from the website of the Journal of Polymer Science, a respected journal published by Wiley since 1946. I began to wonder if there really is anything American about the American Journal of Polymer Science. SAP's website claims that the journal is published out of Los Angeles. The street address appears to be no more than the intersection of two highways, and no phone numbers are listed. I contacted some of the people listed as the journal's editors and reviewers. The few who replied said they have had little contact with SAP. Maria Raimo, a chemist at the Institute of Chemistry and Technology of Polymers in Naples, Italy, had received an e-mail invitation to be a reviewer 4 months earlier. To that point, she had received a single paper—one so poor that "I thought it was a joke," she says. Despite her remonstrations to the then–editor-in-chief, a person of unknown affiliation called David Thomas, the journal published the paper. Raimo says she asked to be removed from the masthead. More than a year later, the paper is still online and the journal still lists Raimo as a reviewer. After months of e-mailing the editors of SAP, I finally received a response. Someone named Charles Duke reiterated—in broken English—that SAP is an American publisher based in California. His e-mail arrived at 3 a.m., Eastern time. To replicate Noutcha's experience, I decided to submit a paper of my own to an SAP journal. And to get the lay of this shadowy publishing landscape, I would have to replicate the experiment across the entire open-access world. The targets The Who's Who of credible open-access journals is the Directory of Open Access Journals (DOAJ). Created 10 years ago by Lars Bjørnshauge, a library scientist at Lund University in Sweden, the DOAJ has grown rapidly, with about 1000 titles added last year alone. Without revealing my plan, I asked DOAJ staff members how journals make it onto their list. "The title must first be suggested to us through a form on our website," explained DOAJ's Linnéa Stenson. "If a journal hasn't published enough, we contact the editor or publisher and ask them to come back to us when the title has published more content." Before listing a journal, they review it based on information provided by the publisher. On 2 October 2012, when I launched my sting, the DOAJ contained 8250 journals and abundant metadata for each one, such as the name and URL of the publisher, the year it was founded, and the topics it covers. There is another list—one that journals fear. It is curated by Jeffrey Beall, a library scientist at the University of Colorado, Denver. His list is a single page on the Internet that names and shames what he calls "predatory" publishers. The term is a catchall for what Beall views as unprofessional practices, from undisclosed charges and poorly defined editorial hierarchy to poor English—criteria that critics say stack the deck against non-U.S. publishers. Like Batman, Beall is mistrusted by many of those he aims to protect. "What he's doing is extremely valuable," says Paul Ginsparg, a physicist at Cornell University who founded arXiv, the preprint server that has become a key publishing platform for many areas of physics. "But he's a little bit too trigger-happy." I asked Beall how he got into academic crime-fighting. The problem "just became too bad to ignore," he replied. The population "exploded" last year, he said. Beall counted 59 predatory open-access publishers in March 2012. That figure had doubled 3 months later, and the rate has continued to far outstrip DOAJ's growth. To generate a comprehensive list of journals for my investigation, I filtered the DOAJ, eliminating those not published in English and those without standard open-access fees. I was left with 2054 journals associated with 438 publishers. Beall's list, which I scraped from his website on 4 October 2012, named 181 publishers. The overlap was 35 publishers, meaning that one in five of Beall's "predatory" publishers had managed to get at least one of their journals into the DOAJ. I further whittled the list by striking off publishers lacking a general interest scientific journal or at least one biological, chemical, or medical title. The final list of targets came to 304 open-access publishers: 167 from the DOAJ, 121 from Beall's list, and 16 that were listed by both. (Links to all the publishers, papers, and correspondence are available online at http://scim.ag/OA-Sting.) The bait The goal was to create a credible but mundane scientific paper, one with such grave errors that a competent peer reviewer should easily identify it as flawed and unpublishable. Submitting identical papers to hundreds of journals would be asking for trouble. But the papers had to be similar enough that the outcomes between journals could be comparable. So I created a scientific version of Mad Libs. The paper took this form: Molecule X from lichen species Y inhibits the growth of cancer cell Z. To substitute for those variables, I created a database of molecules, lichens, and cancer cell lines and wrote a computer program to generate hundreds of unique papers. Other than those differences, the scientific content of each paper is identical. The fictitious authors are affiliated with fictitious African institutions. I generated the authors, such as Ocorrafoo M. L. Cobange, by randomly permuting African first and last names harvested from online databases, and then randomly adding middle initials. For the affiliations, such as the Wassee Institute of Medicine, I randomly combined Swahili words and African names with generic institutional words and African capital cities. My hope was that using developing world authors and institutions would arouse less suspicion if a curious editor were to find nothing about them on the Internet. The papers describe a simple test of whether cancer cells grow more slowly in a test tube when treated with increasing concentrations of a molecule. In a second experiment, the cells were also treated with increasing doses of radiation to simulate cancer radiotherapy. The data are the same across papers, and so are the conclusions: The molecule is a powerful inhibitor of cancer cell growth, and it increases the sensitivity of cancer cells to radiotherapy. There are numerous red flags in the papers, with the most obvious in the first data plot. The graph's caption claims that it shows a "dose-dependent" effect on cell growth—the paper's linchpin result—but the data clearly show the opposite. The molecule is tested across a staggering five orders of magnitude of concentrations, all the way down to picomolar levels. And yet, the effect on the cells is modest and identical at every concentration. One glance at the paper's Materials & Methods section reveals the obvious explanation for this outlandish result. The molecule was dissolved in a buffer containing an unusually large amount of ethanol. The control group of cells should have been treated with the same buffer, but they were not. Thus, the molecule's observed "effect" on cell growth is nothing more than the well-known cytotoxic effect of alcohol. The second experiment is more outrageous. The control cells were not exposed to any radiation at all. So the observed "interactive effect" is nothing more than the standard inhibition of cell growth by radiation. Indeed, it would be impossible to conclude anything from this experiment. To ensure that the papers were both fatally flawed and credible submissions, two independent groups of molecular biologists at Harvard University volunteered to be virtual peer reviewers. Their first reaction, based on their experience reviewing papers from developing world authors, was that my native English might raise suspicions. So I translated the paper into French with Google Translate, and then translated the result back into English. After correcting the worst mistranslations, the result was a grammatically correct paper with the idiom of a non-native speaker. The researchers also helped me fine-tune the scientific flaws so that they were both obvious and "boringly bad." For example, in early drafts, the data were so unexplainably weird that they became "interesting"—perhaps suggesting the glimmer of a scientific breakthrough. I dialed those down to the sort of common blunders that a peer reviewer should easily interdict. The paper's final statement should chill any reviewer who reads that far. "In the next step, we will prove that molecule X is effective against cancer in animal and human. We conclude that molecule X is a promising new drug for the combined-modality treatment of cancer." If the scientific errors aren't motivation enough to reject the paper, its apparent advocacy of bypassing clinical trials certainly should be. The sting Between January and August of 2013, I submitted papers at a rate of about 10 per week: one paper to a single journal for each publisher. I chose journals that most closely matched the paper's subject. First choice would be a journal of pharmaceutical science or cancer biology, followed by general medicine, biology, or chemistry. In the beginning, I used several Yahoo e-mail addresses for the submission process, before eventually creating my own e-mail service domain, afra-mail.com, to automate submission. A handful of publishers required a fee be paid up front for paper submission. I struck them off the target list. The rest use the standard open-access "gold" model: The author pays a fee if the paper is published. If a journal rejected the paper, that was the end of the line. If a journal sent review comments that asked for changes to layout or format, I complied and resubmitted. If a review addressed any of the paper's serious scientific problems, I sent the editor a "revised" version that was superficially improved—a few more photos of lichens, fancier formatting, extra details on methodology—but without changing any of the fatal scientific flaws. After a journal accepted a paper, I sent a standard e-mail to the editor: "Unfortunately, while revising our manuscript we discovered an embarrassing mistake. We see now that there is a serious flaw in our experiment which invalidates the conclusions." I then withdrew the paper. The results By the time Science went to press, 157 of the journals had accepted the paper and 98 had rejected it. Of the remaining 49 journals, 29 seem to be derelict: websites abandoned by their creators. Editors from the other 20 had e-mailed the fictitious corresponding authors stating that the paper was still under review; those, too, are excluded from this analysis. Acceptance took 40 days on average, compared to 24 days to elicit a rejection. Of the 255 papers that underwent the entire editing process to acceptance or rejection, about 60% of the final decisions occurred with no sign of peer review. For rejections, that's good news: It means that the journal's quality control was high enough that the editor examined the paper and declined it rather than send it out for review. But for acceptances, it likely means that the paper was rubber-stamped without being read by anyone. Of the 106 journals that discernibly performed any review, 70% ultimately accepted the paper. Most reviews focused exclusively on the paper's layout, formatting, and language. This sting did not waste the time of many legitimate peer reviewers. Only 36 of the 304 submissions generated review comments recognizing any of the paper's scientific problems. And 16 of those papers were accepted by the editors despite the damning reviews. The results show that Beall is good at spotting publishers with poor quality control: For the publishers on his list that completed the review process, 82% accepted the paper. Of course that also means that almost one in five on his list did the right thing—at least with my submission. A bigger surprise is that for DOAJ publishers that completed the review process, 45% accepted the bogus paper. "I find it hard to believe," says Bjørnshauge, the DOAJ founder. "We have been working with the community to draft new tighter criteria for inclusion." Beall, meanwhile, notes that in the year since this sting began, "the number of predatory publishers and predatory journals has continued to escalate at a rapid pace." A striking picture emerges from the global distribution of open-access publishers, editors, and bank accounts. Most of the publishing operations cloak their true geographic location. They create journals with names like the American Journal of Medical and Dental Sciences or the European Journal of Chemistry to imitate—and in some cases, literally clone—those of Western academic publishers. But the locations revealed by IP addresses and bank invoices are continents away: Those two journals are published from Pakistan and Turkey, respectively, and both accepted the paper. The editor-in-chief of the European Journal of Chemistry, Hakan Arslan, a professor of chemistry at Mersin University in Turkey, does not see this as a failure of peer review but rather a breakdown in trust. When a paper is submitted, he writes in an e-mail, "We believe that your article is original and [all of] your supplied information is correct." The American Journal of Medical and Dental Sciences did not respond to e-mails. About one-third of the journals targeted in this sting are based in India—overtly or as revealed by the location of editors and bank accounts—making it the world's largest base for open-access publishing; and among the India-based journals in my sample, 64 accepted the fatally flawed papers and only 15 rejected them. The United States is the next largest base, with 29 acceptances and 26 rejections. (Explore a global wiring diagram of open-access publishing at http://scim.ag/OA-Sting.) But even when editors and bank accounts are in the developing world, the company that ultimately reaps the profits may be based in the United States or Europe. In some cases, academic publishing powerhouses sit at the top of the chain. Journals published by Elsevier, Wolters Kluwer, and Sage all accepted my bogus paper. Wolters Kluwer Health, the division responsible for the Medknow journals, "is committed to rigorous adherence to the peer-review processes and policies that comply with the latest recommendations of the International Committee of Medical Journal Editors and the World Association of Medical Editors," a Wolters Kluwer representative states in an e-mail. "We have taken immediate action and closed down the Journal of Natural Pharmaceuticals." In 2012, Sage was named the Independent Publishers Guild Academic and Professional Publisher of the Year. The Sage publication that accepted my bogus paper is the Journal of International Medical Research. Without asking for any changes to the paper's scientific content, the journal sent an acceptance letter and an invoice for $3100. "I take full responsibility for the fact that this spoof paper slipped through the editing process," writes Editor-in-Chief Malcolm Lader, a professor of psychopharmacology at King's College London and a fellow of the Royal Society of Psychiatrists, in an e-mail. He notes, however, that acceptance would not have guaranteed publication: "The publishers requested payment because the second phase, the technical editing, is detailed and expensive. … Papers can still be rejected at this stage if inconsistencies are not clarified to the satisfaction of the journal." Lader argues that this sting has a broader, detrimental effect as well. "An element of trust must necessarily exist in research including that carried out in disadvantaged countries," he writes. "Your activities here detract from that trust." The Elsevier journal that accepted the paper, Drug Invention Today, is not actually owned by Elsevier, says Tom Reller, vice president for Elsevier global corporate relations: "We publish it for someone else." In an e-mail to Science, the person listed on the journal's website as editor-in-chief, Raghavendra Kulkarni, a professor of pharmacy at the BLDEA College of Pharmacy in Bijapur, India, stated that he has "not had access to [the] editorial process by Elsevier" since April, when the journal's owner "started working on [the] editorial process." "We apply a set of criteria to all journals before they are hosted on the Elsevier platform," Reller says. As a result of the sting, he says, "we will conduct another review." The editor-in-chief of the Kobe Journal of Medical Sciences, Shun-ichi Nakamura, a professor of medicine at Kobe University in Japan, did not respond to e-mails. But his assistant, Reiko Kharbas, writes that "Upon receiving the letter of acceptance, Dr. Obalanefah withdrew the paper," referring to the standard final e-mail I sent to journals that accepted the paper. "Therefore, the letter of acceptance we have sent … has no effect whatsoever." Other publishers are glad to have dodged the bullet. "It is a relief to know that our system is working," says Paul Peters, chief strategy officer of Hindawi, an open-access publisher in Cairo. Hindawi is an enormous operation: a 1000-strong editorial staff handling more than 25,000 articles per year from 559 journals. When Hindawi began expanding into open-access publishing in 2004, Peters admits, "we looked amateurish." But since then, he says, "publication ethics" has been their mantra. Peer reviewers at one Hindawi journal, Chemotherapy Research and Practice, rejected my paper after identifying its glaring faults. An editor recommended I try another Hindawi journal, ISRN Oncology; it, too, rejected my submission.

– An investigation into the world of so-called "open-access" scientific journals has turned up, well, not much scientific credibility. Inspired by colleagues who'd come across some dodgy-looking journals, John Bohannon made up a study describing the anticancer properties of a chemical, then shipped it to 304 open-access journals. (These types of online journals don't charge readers, unlike standard peer-reviewed journals such as Nature. Instead, the researchers themselves often get charged for publication, explains NPR, which interviews Bohannon.) Of those 304, 157 accepted it, though "its experiments are so hopelessly flawed that the results are meaningless," Bohannon writes for Science. "I created a scientific version of Mad Libs." He wrote it under a false name (Ocorrafoo Cobange) and nonexistent institute (Wassee Institute of Medicine in Asmara), but none of that seemed to matter. Just 98 journals rejected his work of fiction. The others didn't reply or were still contemplating. More alarming: "About 60% of the final decisions occurred with no sign of peer review," Bohannon writes. Of the 106 journals that did go over the paper, 70% still accepted it—including 45% of journals he canvassed from the Directory of Open Access Journals website. Overall, "the data from this sting operation reveal the contours of an emerging Wild West in academic publishing," Bohannon writes. "Ensuring that journals honor their obligation is a challenge that the scientific community must rise to." Click for the full piece.

learning disorder is one of the issues that attract a great deal of attention . the term was primarily suggested by samuel kerck in 1963 to describe a group of children who had problems in developing language , speech , reading , and communicative skills . students suffering from these disorders , without some special helps , have weak performance in such skills ; their friends and families consider them as incapable ; and as a result , they have a low self - esteem and motivation . on the other hand , children suffering from learning disorders form a group of exceptional children with a normal appearance and normal or even higher iq . most of the time we can not identify them before school age , but with entering into school , particularly at their 1 and 2 grade , their problems will gradually appear in reading , writing , calculating , and spelling . these children may have problems in learning one or several academic skills , but merely poor educational performance in one area or even in several areas is not enough to identify children suffering from learning disorder , because poor educational performance may result from factors other than learning disorders ( 1 ) . in dsm-5 ( diagnostic and statistic manual of mental disorder ) learning disorder is renamed as specific learning disorder ; and reading , writing and mathematical disorders that were considered as independent disorders are now considered as specifier of specific learning disorder , meaning that after this psychiatrists or clinical psychologists will never say that a child suffers from reading disorder , but instead they will suggest that the child suffers from specific learning disorder with the specifier of reading ( 2 ) . one of the factors that students may be involved with and has not been given enough attention is emotion failures or alexithymia . inability in cognitive processing of emotional information and regulation of emotions is called alexithymia ( 3 ) . sifneos defines people suffering from alexithymia as people with physical - mental symptoms who can not identify and express emotions . emotion failures have three characteristics : difficulty in identifying feelings , difficulty in describing feelings and externally - oriented thinking styles ; difficulty in identifying feelings occurs when an individual is in distress trying to make a distinction among his / her feelings ; difficulty in describing feelings occurs when an individual can not express what he / she has felt emotionally ; and externally oriented thinking occurs when an individual tends to think about affairs externally , which is in direct contradiction with internally oriented thinking . people suffering from alexithymia or emotion failures exaggerate normal bodily incitements , misinterpret bodily signs of emotional provocation , show their emotional distress through bodily complaints and in measures taken for treatment try to find physical signs ( 3 ) . recent researches indicate that emotion failures have a negative impact on psychological and emotional welfare and a dangerous factor in causing emotional distress , psychological problems and lack of mental health . there is a relationship between emotion failures and pain , arthritis , overweighting , blood pressure , irritable bowel syndrome , depression ( 5 ) , self - injurious behaviors ( 6 ) , nervous lack of appetite , overeating , and job exhaustion ( 7 ) . self - harms or self - injurious behavior has previously been used in the field of education services related to learning disability , and the term self - injury had been used a lot in the case of mental health ( 8) . self - harm behavior is defined as a deliberate act to destroy or change body tissues that damage tissues ( 9,10 ) . this term includes behaviors like self - injury ( self - beating ) and many other indirect forms of body injury ( 11,12 ) . whatever their culture is , youths ( teenagers ) show self - harm behaviors ( 13 ) . moreover , self - harm behavior is defined as behaviors resulting from an individual s damage , bodily or psychic harm and violent behavior towards himself . some researchers have reported that a high percent of students with learning disability have had self - harm behavior . the degree of self - injury in students suffering from learning disability varies from 1.7% to 24% ( 15 ) , but it is reported 41% in some official studies ( 16 ) . fifty two systematic researches on self - harm behaviors were published from 2005 to 2011 worldwide ; in these studies , the frequency of self - harm behavior among students was 16.1 , whereas that of clinical samples varied from 40% to 80% ( 17 ) . emotion regulation training is one of the effective factors in decreasing emotion failures and self - harm behaviors in students suffering from specific learning disorder . regulation of emotion includes all conscious and unconscious strategies used to increase , preserve and decrease emotional , behavioral and cognitive parameters of an emotional response and it is referred to the ability to regulate experience , and understanding and expressing emotions ( 18 ) . the study of psychological texts and studies show that regulation of emotion is a very important factor in assessing the health status and having successful social interactions ( 19,20 ) ; and deficiency in regulating emotion is related to some internal disorders such as depression , anxiety and social isolation , and external disorders such a criminality and aggressive behaviors . emotion regulation training decreases and controls negative emotions and use them in a positive manner . studying the role of emotion regulation in temperament , affection and self - injurious behaviors indicate that negative emotion regulation strategies predict negative temperament , low satisfaction , low positive affection , and high self - injurious behaviors ; and positive emotion regulation strategies predict low negative affection ( 21 ) . moreover , there is a relationship between emotion regulation strategies and the decrease in negative emotions and affective events . furthermore , concentrating on positive strategies of emotion regulation promotes understanding of emotion management ( 22 ) . with respect to the interventions based on regulation of emotions , previous studies have found the efficacy of such a treatment . in one study , it was revealed that cognitive - emotion interventions are effective in perceiving emotional - social behaviors and in modifying complicated behaviors of children suffering from learning disability ; they believed that such interventions increase students thinking ability with regards to hypothesizing and understanding witty remarks in social relations ( 23,24 ) . in another study , it was found that recognition and regulation of emotions and training the manner of solving social problems with cognitive method had a significant effect in improving the performance of students suffering from learning disability in the case of solving social problems , decreasing unsuitable behaviors of aggression , seclusion and emotion failures . moreover , the results showed an improvement in students judgment and an increase in their social self - efficacy in compatibility and increasing friendly behaviors ( 25 - 27 ) . with respect to the role of emotion regulation problems in retention of emotional disorders and self - harm behaviors , it seems that training and applying emotion regulation skills can help improve this area of treatment . hence , the aim of this study was to answer this question : is emotionregulation training effective in decreasing emotion failures and self - injurious behaviors of students suffering from specific learning disorder(sld ) ? this research was conducted experimentally through pre - test , post - test and a control group . research population included all 5 grade male students suffering from specific learning disorder ( case study : 5 grade male students in ardabil in 2015 ) . for sample selection , first we selected 294 students from five schools ( 2 classes from each school ) through multi - step cluster sampling ; all students of the selected classes were evaluated through academic achievement test , kay math mathematic test , diagnostic test of reading disorder and test of writing disorder . then cases who were suspicious of having specific learning disorder underwent a clinical interview . finally , revan intelligence test was usedto identify the lack of any mental disability in the selected students ; and those students with iq score of lower than 90 were omitted from the sample . at the end although the minimum number of the sample in experimental studies must be 15 ( 28 ) , in this research we selected 40 individuals ( suffering from specific learning disorder ) to increase external validity . structured clinical interview on the basis of symptoms in dsm-5:in this research , to identify symptoms of specific learning disorder and their specifiers , we used structured clinical interview on the basis of symptoms described for this disorder in dsm-5 . test of reading disorder : this test was developed by shafiei et al . ( 29 ) in a study titled designing and constructing a screening test to diagnose reading disorder among 1 to 5 grade primary school students in isfahan . the main part of this test for every grade includes a 100-word reading comprehension text which has been confirmed by the experts and authorities of this field . this test was conducted on 200 male and female 1 to 5 grade primary school students who were selected randomly from among 1000 students from five different regions of esfahan . the research was conducted on two groups : one group with reading disorder and a control group . findings revealed a high correlation between scores of rate and accuracy of reading and the total test score . the reported test reliability on the basis of cronbach s alpha was 0.77 and difference between the averages of the two groups was significant ( p > 0.01 ) . with respect to the obtained results , this test can be used as a useful screening test for rapid diagnosis of reading disorder among 1 to 5 grade primary schools students . kay - math mathematic test : kay - math mathematic test was normalized by kenoli . it is used to identify advantages and disadvantages of students in different mathematical areas . on the basis of cronbach s alpha , test of writing expression : in this research , we used dictation tests developed and validated by falahchay . validity of these tests was confirmed by experienced applicants and teachers ; and on the basis of researchers method its reliability was estimated to be 0.91 to 0.95 ( 31 ) . revan intelligence test : this test was developed by revan ( 32 ) in england to measure intelligence among 9 to 18 age groups ; it contains 60 items ( five 12-item series ) . in this test , the average of internal validity coefficient is 0.90 and the average of retest reliability coefficient is 0.82 . the obtained test correlation through intelligence test of wechsler , stanford - binet , labyrinth proteus and goodenough ranged from 0.40 to 0.75 . scale of emotion failures ( tas-20):torento emotion failures ( alexithymia ) scale of children and teenagers is taken from the original version of a questionnaire related to adult alexithymia ( 33 ) . this 20-item questionnaire is graded on the basis of a 3-point scale ( totally , somewhat and not at all ) , and three factors of difficulty in identifying feelings ( 7 items ) , difficulty in describing feelings ( 5 items ) and objective thinking style ( 8 items ) are measured on the basis of a 5-point likert scale ranging from point one totally disagree to point five totally agree ( 34 ) . in this scale , questions 4 , 5 , 10 , 18 , and 19 are graded inversely ; questions 2 , 4 , 7 , 12 , and 17 , questions 1 , 3 , 6 , 9 , 11 , 13 , and 14 and questions 5 , 8 , 10 , 15 , 16 , 18 , 19 , and 20 evaluate difficulty in describing feelings , difficulty in identifying feelings and concentration on external experiences , respectively . the obtained reliability for dependent variable and independent variables has been proven to be high with cronbach s alpha coefficients of well over 0.75 . the reported correlation coefficients of micro - scales of this test with psychic symptom checklists range from 0.17 to 48 ( 34 ) . in the persian version of the scale of alexithymia , the coefficients of cronbach s alpha for the total alexithymia , and the three sub - scales of difficulty in identifying feelings , difficulty in describing feelings and objective thinking are 0.85 , 0.82 , 0.75 , and 0.72 , respectively . questionnaire of self - injurious behaviors : this questionnaire is a self - report questionnaire , whose reliability and validity has obtained by gratz ( 35 ) . the items in this questionnaire are collected through clinical observations , self - reporting by people with self - injurious behaviors , and other self - injurious behaviors reported in other texts . the finished form of this questionnaire was changed by lundh , karim and quilisch from 17 to 16 items ( 36 ) . method of conducting research : after acquiring permission and referring to schools and collecting samples , we randomly selected 20 students as the experimental group and 20 as control the group from all students identified with specific learning disorder . when briefing the participants about the aim of the study , we asked them to participate in a course to treat this disorder . before starting the training methods , we tested both groups with a pretest and asked them to fill the questionnaires . treatment sessions included eight 90-minute group sessions once a week , which was held in a place determined by ardabil ( a city in northwest of iran ) education office . at the end of this course , we tested both groups through a posttest . the obtained data were analyzed using spss software and multivariate analysis of variance ; p<0.05 was considered as significant . a summary of functional instructions of the of emotion regulation training is presented in table 1 . structured clinical interview on the basis of symptoms in dsm-5:in this research , to identify symptoms of specific learning disorder and their specifiers , we used structured clinical interview on the basis of symptoms described for this disorder in dsm-5 . test of reading disorder : this test was developed by shafiei et al . ( 29 ) in a study titled designing and constructing a screening test to diagnose reading disorder among 1 to 5 grade primary school students in isfahan . the main part of this test for every grade includes a 100-word reading comprehension text which has been confirmed by the experts and authorities of this field . this test was conducted on 200 male and female 1 to 5 grade primary school students who were selected randomly from among 1000 students from five different regions of esfahan . the research was conducted on two groups : one group with reading disorder and a control group . findings revealed a high correlation between scores of rate and accuracy of reading and the total test score . the reported test reliability on the basis of cronbach s alpha was 0.77 and difference between the averages of the two groups was significant ( p > 0.01 ) . with respect to the obtained results , this test can be used as a useful screening test for rapid diagnosis of reading disorder among 1 to 5 grade primary schools students . kay - math mathematic test : kay - math mathematic test was normalized by kenoli . it is used to identify advantages and disadvantages of students in different mathematical areas . on the basis of cronbach s alpha , the coefficient of reliability in this test is 0.80 ( 30 ) . test of writing expression : in this research , we used dictation tests developed and validated by falahchay . validity of these tests was confirmed by experienced applicants and teachers ; and on the basis of researchers method its reliability was estimated to be 0.91 to 0.95 ( 31 ) . revan intelligence test : this test was developed by revan ( 32 ) in england to measure intelligence among 9 to 18 age groups ; it contains 60 items ( five 12-item series ) . in this test , the average of internal validity coefficient is 0.90 and the average of retest reliability coefficient is 0.82 . the obtained test correlation through intelligence test of wechsler , stanford - binet , labyrinth proteus and goodenough ranged from 0.40 to 0.75 . scale of emotion failures ( tas-20):torento emotion failures ( alexithymia ) scale of children and teenagers is taken from the original version of a questionnaire related to adult alexithymia ( 33 ) . this 20-item questionnaire is graded on the basis of a 3-point scale ( totally , somewhat and not at all ) , and three factors of difficulty in identifying feelings ( 7 items ) , difficulty in describing feelings ( 5 items ) and objective thinking style ( 8 items ) are measured on the basis of a 5-point likert scale ranging from point one totally disagree to point five totally agree questions 4 , 5 , 10 , 18 , and 19 are graded inversely ; questions 2 , 4 , 7 , 12 , and 17 , questions 1 , 3 , 6 , 9 , 11 , 13 , and 14 and questions 5 , 8 , 10 , 15 , 16 , 18 , 19 , and 20 evaluate difficulty in describing feelings , difficulty in identifying feelings and concentration on external experiences , respectively . the obtained reliability for dependent variable and independent variables has been proven to be high with cronbach s alpha coefficients of well over 0.75 . the reported correlation coefficients of micro - scales of this test with psychic symptom checklists range from 0.17 to 48 ( 34 ) . in the persian version of the scale of alexithymia , the coefficients of cronbach s alpha for the total alexithymia , and the three sub - scales of difficulty in identifying feelings , difficulty in describing feelings and objective thinking are 0.85 , 0.82 , 0.75 , and 0.72 , respectively . questionnaire of self - injurious behaviors : this questionnaire is a self - report questionnaire , whose reliability and validity has obtained by gratz ( 35 ) . the items in this questionnaire are collected through clinical observations , self - reporting by people with self - injurious behaviors , and other self - injurious behaviors reported in other texts . the finished form of this questionnaire was changed by lundh , karim and quilisch from 17 to 16 items ( 36 ) . method of conducting research : after acquiring permission and referring to schools and collecting samples , we randomly selected 20 students as the experimental group and 20 as control the group from all students identified with specific learning disorder . when briefing the participants about the aim of the study , we asked them to participate in a course to treat this disorder . before starting the training methods , we tested both groups with a pretest and asked them to fill the questionnaires . treatment sessions included eight 90-minute group sessions once a week , which was held in a place determined by ardabil ( a city in northwest of iran ) education office . the obtained data were analyzed using spss software and multivariate analysis of variance ; p<0.05 was considered as significant . a summary of functional instructions of the of emotion regulation training is presented in table 1 . the meansd age of the experimental group is 10.20.44 yr , and those of control group are 10.30.39 yr . ( age ranges : 10 - 11yr ) . as demonstrated in table 2 , the mean ( sd ) of the pretest total score in the experiment groupwas 71.4 ( 7.39 ) for emotion failures and it was 40.6 ( 5 ) for the posttest in this group . moreover , the mean ( sd ) of the pretest total score for emotion failures was 63.6 ( 6.63 ) in the control group and the posttest was 65.0 ( 7.79 ) in this group . according to this table , the mean ( sd ) of the pretest total score for self - injurious behaviors of the experiment group was 38.8 ( 2.32 ) and that of the posttest was 24.9 ( 2.82 ) for this group . moreover , the mean ( sd ) of the pretest total score for self - injurious behaviors of the control group was 37.6 ( 2.30 ) and it was 38.1 ( 2.14 ) for that of the posttest this group . before using multivariate analysis of variance for observing the hypotheses , we used tests of box and leven . on the basis of box s test , which was not significant for any variable , the equality condition of variance / covariance was observed correctly ( p=0.152 ) . on the basis of leven test , which was not significant for any variable , the equality condition of intergroup variances was observed . the results of wilkes lambda test indicated that group effect was significant on the variables of emotion failures and self - injurious behaviors [ p 0.001 ] . the obtained results revealed a significant difference between one of the variables of the studied groups . as indicated in table 3 , the results of multivariate analysis of variance showed a significant difference between the average scores of emotion failures with ( f = 134.91 ) and self - injurious behaviors with ( f = 276.34 ) between the experiment and the control groups ( p<0.001 ) . hence , it can be concluded that at the posttest level , emotion regulation training will decreaseemotion failures and self - injurious behaviors among students suffering from specific learning disorder compared to the control group ss= sum of squares , ms= mean square the aim of this study was to examine the effect of emotion regulation training in decreasing emotion failures and self - injurious behaviors among students suffering from specific learning disorder . the results indicated that emotion regulation training decreased emotion failures significantly in students suffering from specific learning disorder compared to the control group . our finding is in line with previous findings ( 5,7,27 ) with regards to the efficacy of emotion regulation group intervention in decreasing symptoms of anxiety and stress , and regulation of emotions . hence , it is obvious that emotions play an important role in one s life and there is a relationship between emotion regulation as a treatment in modifying emotions and self - esteem and positive social interactions . emotion regulation will lead to an effective counteraction with stress - making situations ( 22 ) and will increase activity in response to social situations ( 23 ) . therefore , emotion regulation training can play an important role in improving psychological health and decreasing emotion failures among students suffering from specific learning disorder through making them aware of positive and negative emotions . in justifying this finding , it can be noted that positive strategies of emotion regulation have predicted the increase in positive temperament and consequently the decrease in emotion failures . moreover , the finding supports that of gross and thompson ( 18,19 ) , which revealed a positive relationship between psychological welfare and experiencing positive emotions , and a negative relationship between psychological welfare and experiencing negative emotions . also , it can be stated that since emotion regulation will lead to modification and management of emotions , positive skills of emotion regulation will lead to positive compatibility ; hence , emotion regulation can play an important role in one s life and increase their psychological welfare and positive emotions . moreover , we may refer to the point that students suffering from specific learning disorder most likely can not use positive emotions practically in different life situations ; in contrast , they experience high levels of negative emotions which will cause other problems such as negative self - perception , worrying about interaction with other people and unsuitable social performance . furthermore , the results of multivariate of variance analysis indicated that emotion regulation training had been effective on decreasing self - injurious behaviors among students suffering from specific learning disorder . this supports ( 6,14,26 ) several studies which showed that emotion regulation training had been effective in prevention and treatment of mental disorders and decreasing self - injurious behaviors . moreover , it can be noted that self - injurious behaviors of students suffering from specific learning disorder result from negative emotion regulation strategies , which is the outcome of the lack of emotional sufficiency , unsuitable emotional skills , and having a low ability to resolve contradictions . it seems that these students are not competent in managing theiremotions , controlling theirs and others affections , and developing the necessary social skills to eliminate such obstacles and prevent self - injurious behaviors . hence , insufficient affective growth , difficulty in organizing behaviors and emotions and having negative emotions are characteristics of those who commit self - injurious behaviors ( 21 ) . emotion regulation may be another reason for justifying this finding , and in particular the positive strategy of emotion cognitive re - evaluation will decrease negative feelings and will increase positive feelings and adjustable behaviors ( 21 ) . therefore , emotion regulation training for students suffering from specific learning disorder will lead to a situation in which they can decrease negative feelings as well as self - injurious behaviors through the correct use of emotions , awareness of emotions and accepting them , and expressing emotions especially positive ones in real life situations . moreover , emotion regulation training will lead to a condition in which the students in the experiment group become aware of negative emotions and their negative effect , and try to keep their emotional life healthy through the re - evaluation of emotions in different situations ; taking this approach , they may decrease their physical and psychological problems in particular self - injurious behaviors ( 24 ) . based on the results of this study , we can infer that using emotion regulation training can be effective in decreasing emotion failures and self - injurious behaviors among students suffering from learning disorder through decreasing negative emotions and increasing the positive ones . this study was conducted in ardabil , and the studied sample included male elementary school students . lack of follow - up , and time restriction for providing education were among the other limitations of this study ; and these issues should be taken into account in future studies .

background : a great deal of attention has been given to the study of learning disorders . hence , the aim of this research was to study the effect of emotion regulation training in decreasing emotion failures and self - injurious behaviors among students suffering from specific learning disorder . methods : this was an experimental study with the pre - test , post - test and a control group . research population included all 5th grade male students suffering from specific learning disorder ( case study : 5th grade students in ardabil in 2015 ) . research sample included 40 male students suffering from specific learning disorder ( sld ) who were selected through multi - step cluster sampling and classified into two groups : experimental group ( n= 20 ) and control group ( n= 20 ) . the following tools were used for data collection : kay math mathematic test , raven intelligence test , reading test of shafiei et al , falahchay writing expression , emotion failures scale , self - injurious behavior questionnaire and diagnostic interview based on dsm-5 . data were analyzed by multivariate of variance analysis ( manova ) model in the spss software version 22 . results : the results of manova revealed that emotion regulation training was effective in decreasing emotion failures in all parameters ( difficulty in describing feelings , difficulty in identifying feelings , and externally oriented thinking style ) and self - injurious behaviors in students suffering from specific learning disorder ( p < 0.001 ) . conclusion : in this study , it was found that since emotion regulation training can have a remarkable effect on reducing negative emotions and increasing the positive ones ; this treatment can play an eminent role in decreasing emotion failures and self - injurious behaviors in such students .

SECTION 1. SHORT TITLE. This Act may be cited as the ``Dry-Redwater Regional Water Authority System Act of 2008''. SEC. 2. FINDINGS; PURPOSE. (a) Findings.--Congress finds that-- (1) there are insufficient available supplies of safe water to meet the minimum health and safety standards of the citizens of-- (A) Dawson, Garfield, McCone, Prairie, and Richland Counties of the State; and (B) McKenzie County, North Dakota; (2) McCone and Garfield Counties of the State were-- (A) directly and physically impacted when the Fort Peck Dam was constructed; and (B) to receive certain impact benefits as a result of the Pick-Sloan program; and (3) the water that is contained in the Fort Peck Dam reservoir is managed for purposes relating to-- (A) flood control; (B) the production of hydroelectric power; (C) irrigation; (D) the maintenance of a public water supply; (E) the conservation of fish and wildlife; (F) recreation; and (G) the improvement of water quality. (b) Purpose.--The purpose of this Act is to ensure a safe and adequate municipal, rural, and industrial water supply for the citizens of-- (1) Dawson, Garfield, McCone, Prairie, and Richland Counties of the State; and (2) McKenzie County, North Dakota. SEC. 3. DEFINITIONS. In this Act: (1) Administrator.--The term ``Administrator'' means the Administrator of the Western Area Power Administration. (2) Authority.--The term ``Authority'' means-- (A) the Dry-Redwater Regional Water Authority, which is a publicly owned nonprofit water authority formed in accordance with Mont. Code Ann. Sec. 75-6- 302 (2007); and (B) any nonprofit successor entity. (3) Firm power rate.--The term ``firm power rate'' means the rate charged by the Administrator for the Pick-Sloan Missouri Basin Program--Eastern Division. (4) Pick-sloan program.--The term ``Pick-Sloan program'' means the Pick-Sloan Missouri River Basin Program (authorized by section 9 of the Act of December 22, 1944 (commonly known as the ``Flood Control Act of 1944'') (58 Stat. 891, chapter 665)). (5) Secretary.--The term ``Secretary'' means the Secretary of the Interior. (6) State.--The term ``State'' means the State of Montana. (7) Water system.--The term ``Water System'' means the Dry- Redwater Regional Water Authority System authorized under section 4 for-- (A) Dawson, Garfield, McCone, Prairie, and Richland Counties of the State; and (B) McKenzie County, North Dakota. SEC. 4. DRY-REDWATER REGIONAL WATER AUTHORITY SYSTEM. (a) Cooperative Agreement.-- (1) In general.--The Secretary shall enter into a cooperative agreement with the Authority to provide Federal assistance for the planning, design, and construction of the Water System. (2) Requirements.--A cooperative agreement entered into under paragraph (1) shall specify, in a manner that is acceptable to the Secretary and the Authority-- (A) the responsibilities of each party to the cooperative agreement relating to the Water System, including-- (i) the final engineering report; (ii) an environmental and cultural resource study; (iii) engineering and design; (iv) construction; (v) water conservation measures; and (vi) administration of contracts relating to the performance of the activities described in clauses (i) through (v); (B) any procedure or requirement relating to-- (i) the carrying out of each activity described in subparagraph (A); and (ii) the approval and acceptance of the design and construction of the Water System; and (C) the rights, responsibilities, and liabilities of each party to the cooperative agreement. (b) Use of Federal Funds.-- (1) Federal share.-- (A) In general.--The Federal share of the costs relating to the planning, design, and construction of the Water System shall not exceed 75 percent of the total cost of the Water System. (B) Limitation.--Amounts made available under subparagraph (A) shall not be returnable or reimbursable under the reclamation laws. (2) Compliance with cooperative agreement.--Federal funds made available to carry out this section shall be obligated and expended in accordance with a cooperative agreement entered into by the Secretary under subsection (a)(1). (c) Components.--Components of the Water System facilities for which Federal funds may be obligated and expended under this section shall include-- (1) facilities relating to-- (A) water intake; (B) water pumping; (C) water treatment; and (D) water storage; (2) transmission pipelines and pumping stations; (3) appurtenant buildings, maintenance equipment, and access roads; (4) any interconnection facility that connects a pipeline of the Water System to a pipeline of a public water system; (5) distribution, pumping, and storage facilities that-- (A) serve the needs of citizens who use public water systems; (B) are in existence on the date of enactment of this Act; and (C) may be purchased, improved, and repaired in accordance with a cooperative agreement entered into by the Secretary under subsection (a)(1); (6) electrical power transmission and distribution facilities required for the operation and maintenance of the Water System; (7) any other facility or service required for the development of a rural water distribution system, as determined by the Secretary; and (8) any property or property right required for the construction or operation of a facility described in this subsection. (d) Service Area.--The service area of the Water System shall be-- (1) the area of Garfield and McCone Counties in the State; (2) the area west of the Yellowstone River in Dawson and Richland Counties in the State; (3) the area including, and north of, Township 15N in Prairie County in the State; and (4) the portion of McKenzie County, North Dakota, that includes all land that is located west of the Yellowstone River in the State of North Dakota. (e) Limitation on Availability of Construction Funds.--The Secretary shall not obligate funds for construction of the Water System until the date-- (1) on which the Water System complies with each requirement under the National Environmental Policy Act of 1969 (42 U.S.C. 4321 et seq.); (2) that is 90 days after the date of receipt by Congress of the final engineering report described in subsection (a)(2)(A)(i) that is approved by the Secretary; and (3) on which the Secretary publishes a written finding that the water conservation plan developed pursuant to section 6 contains water conservation measures for the operation of the Water System that are-- (A) prudent; (B) reasonable; and (C) economically and financially feasible. (f) Limitation on Use of Federal Funds.-- (1) In general.--Any cost relating to the operation, maintenance, or replacement of the Water System-- (A) shall not be a Federal responsibility; and (B) shall be paid by the Water System. (2) Federal funds.--The Secretary shall not obligate or expend Federal funds for the operation, maintenance, or replacement of the Water System. (g) Title to the Water System.--Title to the Water System shall be held by the Authority. SEC. 5. USE OF POWER FROM PICK-SLOAN PROGRAM. (a) Findings.--Congress finds that McCone and Garfield Counties in the State were designated-- (1) as impact counties during the period in which the Fort Peck Dam was constructed; and (2) to receive impact mitigation benefits in accordance with the Pick-Sloan program. (b) Availability of Power.-- (1) In general.--Subject to paragraph (2), the Administrator shall make available to the Water System a quantity of power required to meet the pumping and incidental operation requirements of the Water System-- (A) from the water intake facilities; and (B) through-- (i) the water treatment facilities; and (ii) all first water distribution pumping facilities. (2) Eligibility.--The Water System shall be eligible to receive power under paragraph (1) if the Water System-- (A) operates on a not-for-profit basis; and (B) is constructed pursuant to a cooperative agreement entered into by the Secretary under section 4(a)(1). (3) Rate.--The Administrator shall establish the cost of the power described in paragraph (1) at the firm power rate. (4) Recovery of expenses.--The Administrator shall recover the costs associated with the quantity of power used by the Authority under paragraph (1). (5) Responsibility for expenses.--The Authority shall be responsible for the payment of the costs described in paragraph (4). SEC. 6. WATER CONSERVATION PLAN. (a) In General.--The Authority shall develop a water conservation plan containing-- (1) a description of water conservation objectives; (2) a description of appropriate water conservation measures; and (3) a time schedule for carrying out the measures described in paragraph (2) and this Act to meet the water conservation objectives described in paragraph (1). (b) Design Requirement.--The water conservation plan developed under subsection (a) shall be designed to ensure that users of water provided by the Water System will use the best practical technology and management techniques to conserve water. (c) Public Participation.--Section 210(c) of the Reclamation Reform Act of 1982 (43 U.S.C. 390jj(c)) shall apply to each activity carried out under this Act. SEC. 7. AUTHORIZATION OF APPROPRIATIONS. (a) Water System.--There is authorized to be appropriated to carry out the planning, design, and construction of the Water System $115,116,000 for the period of fiscal years 2009 through 2019. (b) Cost Indexing.--The amount authorized to be appropriated under subsection (a) may be increased or decreased in accordance with ordinary fluctuations in development costs incurred after January 1, 2008, as indicated by any available engineering cost indices applicable to construction activities that are similar to the construction of the Water System.

Dry-Redwater Regional Water Authority System Act of 2008 - Directs the Secretary of the Interior to enter into a cooperative agreement to provide federal assistance for the planning, design, and construction of the Dry-Redwater Regional Water Authority System for specified counties in Montana and North Dakota. Lists agreement requirements. Limits the federal share of planning, design, and construction of the System to 75% of the total cost. Delineates the components of System facilities for which federal funds may be expended and the System's service area. Limits the obligation of funds for construction. Provides that any cost relating to the System's operation, maintenance, or replacement shall not be a federal responsibility and shall be paid by the System. Directs the Administrator of the Western Area Power Administration to make available to the System a quantity of power required to meet the System's pumping and incidental operation requirements from the water intake facilities and through the water treatment facilities and all first water distribution pumping facilities. Makes the System eligible to receive power only if it operates on a nonprofit basis and is constructed pursuant to the agreement. Directs the Authority to develop a water conservation plan containing a description of water conservation objectives and measures and a schedule for carrying out such measures. Requires the plan to be designed to ensure that users of water provided by the System will use the best practical technology and management techniques to conserve water.

FILE - In this March 15, 2017, file photo, Defendant Aaron Hernandez listens during his double murder trial in Suffolk Superior Court, in Boston. A judge is set to hear arguments in a push by lawyers... (Associated Press) FALL RIVER, Mass. (AP) — Former NFL star Aaron Hernandez's conviction in a 2013 murder can be erased because he died before his appeal was heard, a judge ruled Tuesday. Judge E. Susan Garsh said case law in Massachusetts has long established that defendants who have not had the merits of their appeals decided before they die have the right to have their convictions vacated. She said she was compelled to follow it. The former New England Patriots tight end hanged himself in his cell in a maximum-security prison last month while serving a life sentence on a first-degree murder conviction in the death of semi-professional football player Odin Lloyd. He died five days after being acquitted in a separate double slaying in 2012. Lawyers for Hernandez had argued that the state's highest court had applied the legal doctrine "without exception," even in cases of suicide. They said his conviction wasn't considered final because the automatic appeal he was entitled to had not been heard at the time of his death. Prosecutor Patrick Bomberg had argued that Hernandez "should not be able to accomplish in death what he could not accomplish in life." But Garsh rejected the argument that Hernandez had forfeited his right to appeal by taking his own life, saying no one can ever know for sure why Hernandez killed himself. Hernandez's appellate attorney, John Thompson, told reporters after the hearing that he believes it's still uncertain as to whether Hernandez took his own life. Thompson says he has recent correspondence from Hernandez in which he was interested in pursuing an appeal of his conviction. Thompson also said because Hernandez died in prison, it will be difficult to definitively determine how he died. Hernandez's lead attorney in his recent double murder trial, Jose Baez, has pledged to do an independent investigation into his death. State police said in an investigative report that Hernandez was found naked on April 19 and hanging from a bed sheet tied around the window bars of his cell. Correction officers found that cardboard had been shoved into the tracks of Hernandez's cell door to prevent the door from opening. Hernandez also had put shampoo on the floor to make it slippery, the report states. An autopsy performed by the state medical examiner's office determined the cause of Hernandez's death was asphyxia by hanging and the manner of death was suicide. Hernandez, who grew up in Bristol, Connecticut, and played football at the University of Florida, was considered an up-and-coming star during his three seasons with the Patriots. He was cut from the team hours after his arrest in the killing of Lloyd. ||||| Fall River, Massachusetts (CNN) Aaron Hernandez died a convicted murderer, but in the eyes of the law, his conviction has been erased. On Tuesday, a Massachusetts judge vacated Hernandez's murder conviction after the former NFL star's suicide. Minutes later, the Bristol County district attorney said prosecutors will appeal the judge's decision. Hernandez was serving a life sentence for the June 2013 murder of Odin Lloyd . Hernandez hanged himself in his prison cell April 19, just days after his acquittal on double-murder charges in a separate case. Massachusetts courts have generally recognized a legal rule called "abatement ab initio," or abatement, in which convictions are thrown out if a defendant dies before his or her appeal is heard. The idea of abatement is to ensure the right to appeal for defendants , Suffolk University law professor Rosanna Cavallaro told CNN. JUST WATCHED Odin Lloyd's mother speaks out on son's death Replay More Videos ... MUST WATCH Odin Lloyd's mother speaks out on son's death 01:16 After the judge's ruling, Lloyd's mother spoke to reporters. "I know everyone is looking for me to be angry, but I'm not," Ursula Ward said. "I know God is fighting this battle for me. He also said be still, and know that I am God. And I am obeying him." Ward said the judge's decision doesn't change her mind that Hernandez killed her son. "In our book, he's guilty, and he's going to always be guilty," she said, holding back tears. "But I know one day, I'm going to see my son. And that's the victory that I have (that) I'm going to take with me." The arguments on both sides Hernandez attorney John Thompson said the manner of death should not matter -- when a person dies while his conviction is under direct appeal, the conviction should be vacated. But prosecutors argued that abating Hernandez's conviction would "reward the defendant's conscious, deliberate and voluntary act" of killing himself and that the abatement rule has no solid historical or legal basis. "A defendant, who can cut off his own criminal appeal by suicide and stall civil litigation by a stay of proceedings ... has the reins of the entire justice system in his own hands," prosecutors wrote. In court filings last week, they produced two pieces of evidence they said bolstered their argument. First, one fellow inmate told authorities that Hernandez had mentioned he heard a rumor about the abatement rule, according to the court documents. Second, Hernandez's suicide note for his fiancée said "YOU'RE RICH," underlined twice. The issue is relevant because Lloyd's mother has brought a wrongful death suit against Hernandez's estate. And such lawsuits often rely on a criminal conviction as their basis of facts. Ultimately, Judge Susan Garsh said the court cannot say for certain why Hernandez committed suicide. She described it as a "tragic act that had complex and myriad motives." After the judge's decision an attorney for Lloyd's mother said the civil wrongful death case will proceed. "The abatement issue really shouldn't affect our case," attorney Doug Sheff said. A history of abatements Abatement has generally been recognized in Massachusetts even in high-profile cases of suicide. John Salvi was convicted of murder in 1996 for opening fire at a Planned Parenthood clinic in Brookline, but his conviction was vacated when he committed suicide in prison before his appeal was heard. And the death of John J. Geoghan, a priest at the center of the Catholic Church's sexual abuse scandal, also led to the abatement of his conviction But Bristol County District Attorney Thomas Quinn criticized the "antiquated" practice of abatement, especially when an inmate commits suicide while his conviction is under appeal. "By his suicide, the defendant waives his right to appeal," Quinn said Tuesday. "To allow an archaic rule to erase a jury's verdict flies in the face of common sense and basic fairness." Quinn said he will appeal the erasing of Hernandez's conviction. "He should not be able to accomplish in death what he could not have accomplished in life."

– He'll enter the history books as a former NFL star and a one-time inmate but, ultimately, not a convicted murderer. Judge E. Susan Garsh on Tuesday agreed to erase Aaron Hernandez's conviction in a 2013 murder because he died before his appeal was heard. Garsh said she was compelled to follow Massachusetts case law, which has long established that defendants who have not had the merits of their appeals decided before they die have the right to have their convictions vacated, reports the AP. Prosecutor Patrick Bomberg had argued Hernandez "should not be able to accomplish in death what he could not accomplish in life." Lawyers for Hernandez countered that the state's highest court had applied the legal doctrine "without exception," even in cases—like Hernandez's—of suicide. Garsh rejected the argument that Hernandez had forfeited his right to appeal by taking his own life on April 19, saying no one can ever know for sure why Hernandez killed himself. Prosecutors plan to appeal Garsh's decision, reports CNN, which notes they based their original argument on two pieces of evidence: an inmate's testimony that Hernandez had heard a "rumor" about the legal principle, and the suicide note left for his fiancee. "YOU'RE RICH," he wrote to Shayanna Jenkins-Hernandez. CNN explains the mother of Odin Lloyd, the man Hernandez was originally convicted of murdering, hit Hernandez's estate with a wrongful death lawsuit. The absence of a criminal conviction could adversely affect her civil case.

relativistic fluid dynamics provide a simple but intuitive description of many physical systems . the hot and compressed nuclear matter behaves like a compressible fluid and fluid dynamical effects are observed in high energy heavy ion reactions @xcite . supernova or neutron star may be another situation where the relativistic heat - conducting fluid gives a satisfactory description . the standard theory of the relativistic dissipative fluid proposed by eckart @xcite and a similar one by landau and lifshitz @xcite was analysed by hiscock and lindblom @xcite and it was found to be unstable , acausal and ill posed in the linear regime near equilibrium . a more complicated extended hydrodynamic theory has been proposed by israel and stewart @xcite which is free of the most part of the troubles of the standard theory . the hiscock and lindblom studies were dedicated to causality , stability , hyperbolicity and to the connection between them . in @xcite the solution discussion was restricted to spatially homogeneous fluid . this paper will improve the dimensional restriction considering the evolution equations for the plane symmetric motion ( 1 + 1 dimensional ) of the relativistic heat - conducting fluid and propose a complementary analysis dedicated to group - invariant solutions study . symmetry analysis is a systematic and accurate way to obtain solutions of differential equations . the lie symmetry group method is well known but the major obstacle in the application of this method to partially differential equations is the large number of tedious calculations usually involved . we begin our analysis by the calculation of the lie symmetry group for both eckart and israel - stewart fluids using , for the equation of state , the high temperature limit of the ideal gas , where @xmath0 . this constraint allows us to eliminate from the fluid equations two dependent variables , in particular , we substitute the temperature @xmath1 and the pressure @xmath2 in favour of the energy density @xmath3 and the number density @xmath4 . next , we make a systematic classification of the solutions constructing the optimal system of transformations . the investigation of the solutions is completed by solving the reduced system of equations ; we present both analytical and numerical solutions . will display the system of equations of the relativistic dissipative fluid in its general form eqs . and in the particular case of heat - conducting theory eqs . . the application of the lie symmetry group method to differential equations and the corresponding lie algebra of the fluid equations are presented in . is devoted to integrability conditions and invariants , to the classification of the solutions and to group invariant solutions analysis . possible applications of the group - invariant solutions to high energy collisions , miscellaneous comments and final conclusions are discussed in . in the particle frame , used by eckart , the energy tensor @xmath5 and the particle flux vector @xmath6 take the form @xcite : @xmath7 where @xmath8 is a unit time - like vector field which may be thought of as the four - velocity of the fluid , @xmath9 is the minkowski metric diag(-1,1,1,1 ) , @xmath3 the energy density of the fluid , @xmath2 the thermodynamical pressure , @xmath4 the number density , @xmath10 is the heat flow , @xmath11 the bulk stress and @xmath12 the shear stress . the heat conducting case is obtained by setting @xmath13 and @xmath14 . in this particular condition the heat flow obeys the following phenomenological law @xcite : @xmath15 where beside the usual thermal conductivity @xmath16 and temperature @xmath1 we have a new phenomenological coefficient @xmath17 @xcite . setting @xmath18 we obtain the standard eckart heat conducting fluid theory . the conservation laws : @xmath19 and the equation form the complete system of equations of the general theory of relativistic dissipative fluids . if we write the four - velocity in the form @xmath20 , the heat flow vector , which is orthogonal to @xmath8 , will be @xmath21 and the system of equations of the fluid becomes : @xmath22\partial_t\psi - \left[\left(p+\rho\right)\cosh\psi + 2 q \sinh\psi\right]\partial_x\psi = 0 & \\ \fl \cosh\psi \partial_x p - \sinh\psi \partial_t p + \sinh\psi \partial_x q - \cosh\psi \partial_t q \\ \fl - \left[\left(p+\rho\right)\cosh\psi + 2 q \sinh\psi\right]\partial_t\psi + \left[\left(p+\rho\right)\sinh\psi + 2 q \cosh\psi\right]\partial_x\psi = 0 & \\ \fl t^{-1}\left(\cosh\psi \partial_x t - \sinh\psi \partial_t t \right ) + \bar\beta_1 \left(\sinh\psi \partial_x q - \cosh\psi \partial_t q \right ) \\ \fl + \sinh\psi \partial_x\psi - \cosh\psi \partial_t\psi + \frac{q}{\kappa t } = 0 & \end{array}\ ] ] we will supplement the eqs . by an equation of state ( eos ) for the fluid and a thermodynamic expression for @xmath17 . choosing the high temperature limit of an ideal gas , the equation of state is @xmath23 finally , we take the thermal conductivity to be constant and the second - order thermodynamic coefficient @xmath17 to be given by @xmath24 ; the parameter @xmath25 will be @xmath26 for the israel - stewart theory and @xmath27 for the eckart theory . the equation allows us to eliminate @xmath1 and @xmath2 in favour of @xmath3 and @xmath4 , obtaining finally a closed set of evolution equations for four variables @xmath28 . the symmetry group of a system of differential equations is the largest local group of transformations acting on the independent and dependent variables of the system with the property that it transforms solutions of the system to other solutions . let @xmath29 be a system of differential equations . a symmetry - group of the system @xmath29 is a local group of transformations @xmath30 acting on an open subset @xmath31 of the space of independent and dependent variables of the system with the property that whenever u = f(x ) is a solution of @xmath29 , and whenever @xmath32 is defined for @xmath33 , then @xmath34 is also a solution of the system . the symmetry group infinitesimal generator is defined by : @xmath35 and the first order prolongation of @xmath36 is : @xmath37 where , for example , @xmath38 and @xmath39 is the total derivative and @xmath40 , etc . suppose @xmath41 is a system of differential equations , where @xmath42 . if @xmath30 is a local group of transformations acting on @xmath31 and @xmath43=0,\;\nu = 1, ... ,l,$ ] whenever @xmath44 , for every infinitesimal generator @xmath45 of @xmath30 , then @xmath30 is a symmetry group of the system . the standard procedure is based on finding the infinitesimal coefficient functions @xmath46 and @xmath47 . substituting the general formulae for @xmath48 and equating the coefficients of various monomials in the first and second order partial derivatives of @xmath49 and @xmath50 , we find the defining equations . we wish to determine all possible coefficient functions @xmath51 and @xmath52 by solving the defining equations system so that the corresponding one - parameter group @xmath53 will be the symmetry group of the equations . these solutions are : @xmath54 where @xmath55 are constants . the basis of the corresponding lie algebra are : @xmath56 because we have the lie algebra of the equations we want to know if the general solution of the system of differential equations can be found by quadratures . this thing is possible if the lie group is solvable . the requirement for solvability is equivalent to the existence of a basis @xmath57 of lie algebra @xmath58 such that @xmath59=\sum\limits_{k=1}^{j-1}c_{ij}^kv_k\ ] ] whenever @xmath60 . looking at the commutator table of the lie algebra we will see that the requirement of solvability is fulfilled for both eckart and israel - stewart theories . -4 mm crrrr & @xmath61 & @xmath62 & @xmath63 & @xmath64 + @xmath61 & 0 & 0 & @xmath61 & 0 + @xmath62 & 0 & 0 & @xmath62 & 0 + @xmath63 & -@xmath61 & -@xmath62 & 0 & 0 + @xmath64 & 0 & 0 & 0 & 0 + crrr & @xmath61 & @xmath62 & @xmath63 + @xmath61 & 0 & 0 & @xmath61 + @xmath62 & 0 & 0 & @xmath62 + @xmath63 & -@xmath61 & -@xmath62 & 0 + & & & + -8 mm we use the method of characteristics to compute the invariants of the lie algebra hopping that the reduced system , which can be obtained using the invariants of the group , will help us to solve the system of equations . an n - th order differential invariant of a group g is a smooth function depending on the independent and dependent variables and their derivatives , invariant on the action of the corresponding n - th prolongation of g @xcite . suppose that we have the following generator : @xmath65 a local invariant @xmath66 of @xmath67 is a solution of the linear , homogeneous first order partial differential equation : @xmath68 the classical theory of such equations shows that the general solution of equation can be found by integrating the corresponding characteristic system of differential equations , which is @xmath69 doing this integration we get , in this case , five invariants ; we now re - express the next generator of lie algebra in terms of these five invariants and then we perform another integration . we continue this calculation until we re - express and integrate the last generator ; at this point we obtain a set of invariants that represent the system of independent invariants of this group . the system of invariants can be used to reduce the order of the original equations - constructing the reduced order system of equations . doing this one can hope to find simple equations that can be integrated ( for example @xcite ) . a solution of the system of partial differential equations is said to be @xmath30-invariant if it is unchanged by all the group transformations in @xmath30 . in general , to each s - parameter subgroup @xmath70 of the full symmetry group @xmath30 of a system of differential equations , there will correspond a family of group - invariant solutions . since there are almost always an infinite number of such subgroups , it is not usually feasible to list all possible group - invariant solutions of the system . we need an effective systematic means of classifying these solutions , leading to an optimal system of group - invariant solutions from which every other solution can be derived . since the elements @xmath58 @xmath71 @xmath30 not in the subgroup @xmath70 will transform an @xmath70-invariant solution to some other group - invariant solution , only those solutions not so related need to be listed in our optimal system . an optimal system of s - parameter subgroups is a list of conjugancy inequivalent s - parameter subgroups with the property that any other subgroup is conjugate to precisely one subgroup in the list ( conjugancy map : @xmath72 ) . let @xmath30 be a lie group with lie algebra @xmath58 ; for each @xmath73 , the adjoint vector @xmath74 at @xmath75 @xmath58 is @xmath76=-[v , w ] . $ ] if @xmath73 generates the one - parameter subgroup @xmath77 $ ] , then @xmath78 will generate the conjugate one - parameter subgroup @xmath79 . now we can construct the adjoint representation @xmath80 of the lie group by summing the lie series @xmath81+\frac{\varepsilon ^2}2[v,[v , w]]- ... \ ] ] obtaining the adjoint table . -5 mm crrcr & * @xmath61 * & * @xmath62 * & * @xmath63 * & * @xmath64 * + & @xmath61 & @xmath62 & @xmath82 & @xmath64 + * @xmath62 * & @xmath61 & @xmath62 & @xmath83 & @xmath64 + * @xmath63 * & @xmath84 & @xmath85 & @xmath63 & @xmath64 + * @xmath64 * & @xmath61 & @xmath62 & @xmath63 & @xmath64 + crrc & * @xmath61 * & * @xmath62 * & * @xmath63 * + & @xmath61 & @xmath62 & @xmath82 + * @xmath62 * & @xmath61 & @xmath62 & @xmath83 + * @xmath63 * & @xmath84 & @xmath85 + & & & + -7 mm finding the optimal system is a well known standard method @xcite ; we have found an optimal system of one - dimensional ( @xmath86 ) sub - algebras to be that spanned by : @xmath87 each symmetry of the optimal system of transformations will be treated separately . \1 ) the fluid is spatially homogeneous and because the reduced system is very simple the fluid equations can be immediately integrated analytically . the shows that , for any initial state , the eckart theory is unstable : as @xmath88 then @xmath89 and @xmath90 . the same thing happens , for the israel - stewart theory , only if the initial velocity is higher than the critical value @xmath91 but it can be stable for initial values @xmath92 , where @xmath93 . this spatially homogeneous case was also studied by hiscock and lindblom @xcite and they found the critical value around @xmath94 . \2 ) also in this stationary case , the reduced system is very easy to integrate and the space dependence of the velocity can be observed in the . for the eckart fluid , if the initial velocity is higher then 0.77 then as @xmath95 we have @xmath96 . if we correlate this stationary behaviour with the previous result , we can comment that the stationary solution will increase in time for any initial eckart velocity conditions ; the stewart - israel fluid has the chance to decrease when @xmath97 for a initial velocity smaller that @xmath91 . \3 ) the invariants of the characteristic equation @xmath98 are @xmath99 and for the eckart fluid the reduced system of equations take the following form : @xmath100 \rightarrow\alpha= n_0 \left(\sinh\psi+y\cosh\psi\right)^{-1 } \\ \fl q=\frac{\rho_y}{6\psi_y } \frac{(1+y^2)\cosh(2\psi)+2(-1+y^2+y\sinh(2\psi)}{1-y^2 } \\ \fl 3q_y+4\rho\psi_y+\rho_y \frac{2y\cosh(2\psi)+(1+y^2)\sinh(2\psi)}{1-y^2}=0 \\ \fl \rho_y-\frac{3kn_0}{\chi}\frac{q}{\sinh\psi+y\cosh\psi } + 2\rho\frac{1+\left[(1+y^2)\cosh(2\psi)+2y\sinh(2\psi)\right]\psi_y}{(1 + y^2)\sinh(2\psi)+2y\cosh(2\psi ) } = 0 } \ ] ] where @xmath101,etc .. the system of equations can be decoupled and the behaviour of the velocity numerical solution can be observed in the first picture of the . it is important to mention that the first picture of the shows that we have both exponentially increasing and decreasing solutions , which means that we found a good eckart velocity solution . also important is that if the initial velocity is smaller than @xmath102 we have only decreasing solutions . further numerical investigations of the equation are needed in order to obtain information about the stability , initial condition dependence , etc .. for the israel - stewart fluid the reduced system is much more complicated and we did nt succeed to solve the equations . \4 ) for this optimal transformation the invariant is @xmath103 ; if we choose @xmath104 the reduced system can be easily decoupled and for the eckart fluid the solutions are : @xmath105\right ] \\ n = n_0\sqrt{(1+v)/(1-v)},\>\ > \rho_y=0,\>\ > q=\frac{2\chi}{3kn_0}\rho\frac{v_y}{(1+v)^2 } } \ ] ] the velocity solution is ploted in the second picture of the . this @xmath106 dependence is typical for a wave type solution but as @xmath107 we arrive again to wrong physical situation : @xmath108 . the choice @xmath104 does not affect the physics , it can change the @xmath109 axes direction or it can scale the space coordinate . the israel - stewart reduced system is also integrable but we found complex velocity solution . \5 ) the invariants are @xmath110 . after some calculations , the reduced system of equations becomes : @xmath111 \right)_y + \frac{(a-2)\sinh\psi } { \cosh\psi+y\sinh\psi } \\ \fl + \frac{a((1+y)\sinh(2\psi)+2y)}{(\sinh\psi+y\cosh\psi)(\cosh\psi+y\sinh\psi ) ( 6(y^2 - 1)\psi_y-3a ) } \ } \\ \fl \left[1+\frac{3kn_0}{\chi } \frac{2y\cosh(2\psi)+(1+y^2)\cosh(2\psi)+2(y^2 - 1)}{(\sinh\psi+y\cosh\psi ) ( \cosh\psi+y\sinh\psi)(6(y^2 - 1)\psi_y -3a ) } \right]^{-1 } \\ \fl \theta= \frac{\left[w^{-1}w_y\left(2y\cosh 2\psi+(1+y^2)\cosh 2\psi+2(y^2 - 1)\right ) + a\left ( ( 1+y)\sinh 2\psi+2y\right ) \right ] } { \left(6(y^2 - 1)\psi_y-3a\right ) } \\ \fl \frac{w_y}{w}\left(y\sinh 2\psi+\cosh 2\psi-2 - 3y\theta\right)-3y\theta_y + a\left(\sinh 2\psi-3\theta\right)-2\left(2y+3\theta\right)\psi_y=0 } \ ] ] the system of equations can be decoupled and solved numerically . the behaviour of the numerical velocity solution is the same as that was founded for the third optimal transformation ; ofcourse , more precise numerical investigations are also needed . \6 ) in this case the invariants are @xmath112 and the reduced system is : @xmath113\psi_y & = 0\\ \sigma^{-1}\sigma_y\left(1/3\cosh\psi-1/3a\sinh\psi+\alpha\sinh\psi -a\alpha\cosh\psi\right ) \\ + \alpha_y \left(\sinh\psi - a\cosh\psi\right)-1/3\sinh\psi-\alpha\cosh\psi \\ + \left[4/3\left(\sinh\psi - a\cosh\psi\right ) + 2\alpha\left(\cosh\psi - a\sinh\psi\right)\right]\psi_y & = 0\\ \cosh\psi\left(\rho^{-1}\rho\sigma^{-1}\sigma - n^{-1}n_y \right ) -\sinh\psi\left[\rho^{-1}\rho\left(a\sigma^{-1}\sigma+1\right ) -n^{-1}n_y \right ] \\ + \left(\sinh\psi - a\cosh\psi\right)\psi_y + 3n\alpha k/\kappa & = 0 \end{array}\ ] ] we can decouple the equations and in the end we obtain the following equation : @xmath114 where @xmath115 are constants and @xmath116 are known functions of @xmath117 . the equation is integrable @xcite ; because the integration algorithm is very long we will present only the final form of the equation that can be integrated : @xmath118 where @xmath119 $ ] and @xmath120 are constants ; @xmath121 , which is a function of @xmath117 via @xmath122 , has to be found from the equation @xmath123 . because the analytical solution formula is very long and complicated we do nt write it here , we prefer to mention that it has the same exponentially increasing trouble founded before . for the 7),8 ) and 9 ) transformation we ca nt reduce the fluid system of equations . the lie symmetry group method was applied to two different relativistic heat - conducting fluid theories , the eckart theory and the israel - stewart theory , and a comparison between them has been made . we may summarise the results as follows : * applying the lie symmetry group method to both fluids , we found that the lie algebra of the eckart theory has an additional transformation , namely the space , time and particle density dilatation @xmath124 . * a systematic classification of the solutions is done by constructing the optimal system of transformations . * solving all the eckart s reduced systems of equations , we found that during the evolution of the fluid , there are , beside the exponentially increasing velocities , also solutions with good physical behaviour ; we mention that in the 1 dimensional approximation , for the eckart theory , there are only exponentially increasing solutions . * due to a different ( more complicate ) phenomenological law , the optimal transformation system of the israel - stewart theory is trivial and as a consequence the reduced systems of equations are not very much simplified but the transformation invariants ; anyway , we found good physical behaviour for the spatially homogeneous and stationary solutions . due to the fact that each fluid has a different phenomenological law , the corresponding symmetry groups is different . we considered here only two values for the parameter @xmath25 that leads us to some well known fluids , but performing the same kind of analysis for other @xmath25 values , we could shed some light on the domain in which the relativistic heat - conducting fluid theory is well behaved . taking into account the bulk stress and the shear stress , the phenomenological law becomes more general but then the fluid equations will be more difficult to solve and in spite of the tremendous work needed , it is possible to obtain a very simple symmetry group that does not help very much on the reduced system integration . it is important to point out that we are looking to find the simplest well behaved fluid theory in order to be solved much easier . anyway , it is an open subject that needs some attention . because the 1 + 1 dimensional approximation is appropriate to describe the collision of two highly lorentz contracted heavy ions , further analysis of the relativistic fluid , with or without viscosities , with different @xmath25 values , etc . , are very important because , for some years , any theoretical predictions can be compared with the experimental data that were taken at ags or cern . the concept of a quark - gluon plasma ( qgp ) predicted for heavy ion collisions @xcite has been the driving force for the experimental and theoretical studies of hadronic matter at high energy densities . a lot of theoretical work has been done in order to use the hydrodynamical models in heavy ion physics and several models based on relativistic hydrodynamics exist , the reader is reffered to refs . @xcite . i wish to thank prof . m. viinescu for continue encouraging this work . 5 edited by csernai l p 1997 _ heavy ion physics _ * 5 * 321 - 474 eckart c 1940 _ phys . rev . _ * 58 * 919 landau l d and lifshitz l 1958 _ fluid mechanics _ ( addison - wesley , reading , mass . ) sec . 127 hiscock w and lindblom l 1983 _ ann . phys . _ * 151 * 466 hiscock w and lindblom l 1985 _ _ d * 31 * 725 hiscock w and lindblom l 1987 _ _ d * 35 * 3723 hiscock w and lindblom l 1988 _ _ a * 131 * 509 israel w 1976 _ _ * 100 * 310 israel w and stewart j m 1979 _ _ a * 357 * 43 israel w and stewart j m 1979 _ _ * 118 * 341 olver p j _ applications of lie groups to differential equations _ 1986 ( springer verlag ) kamke e 1961 _ diff . lsungsmethoden und lsungen _ verlag ) for example , mller b _ lecture given at the nato advanced study institute _ duke - th-92 - 36 strottman d 1994 _ _ a * 566 * 245c bjorken j d 1983 _ _ d * 27 * 140

the lie symmetry group for 1 + 1 dimensional relativistic heat - conducting fluid is calculated for two different theories , eckart and israel - stewart and a comparison between the group - invariant solutions has been made . both fluids were founded to be physical acceptable in the sense that during the evolution of the fluid there are three velocity solutions that are decreasing exponentially for particular choices of the initial conditions .

SECTION 1. SHORT TITLE. This Act may be cited as the ``Maritime Trust Fund Act''. SEC. 2. MODIFICATIONS IN EXCISE TAX ON TRANSPORTATION OF PASSENGERS BY WATER. (a) Increase in Amount of Tax.--Subsection (a) of section 4471 of the Internal Revenue Code of 1986 is amended to read as follows: ``(a) In General.--There is hereby imposed a tax equal to 5 percent of the amount paid by each passenger for a covered voyage.'' (b) Modification to Covered Voyages.--Clause (i) of section 4472(1)(A) of such Code is amended by inserting before the comma ``and which has a port of call not located in the United States or a possession of the United States''. (c) Effective Date.--The amendments made by this section shall take effect on the date of the enactment of this Act. SEC. 3. EXCISE TAX ON CONTAINERS USED TO IMPORT OR EXPORT COMMERCIAL CARGO. (a) In General.--Chapter 36 of the Internal Revenue Code of 1986 (relating to certain other excise taxes) is amended by inserting after subchapter B the following new subchapter: ``Subchapter C--Containers Used To Import or Export Cargo ``Sec. 4476. Imposition of tax. ``SEC. 4476. IMPOSITION OF TAX. ``(a) General Rule.--There is hereby imposed a tax on any taxable container use. ``(b) Amount of Tax.--The amount of the tax imposed by subsection (a) on any taxable container use is $15 per 20-foot equivalent unit of the container. ``(c) Liability and Time of Imposition of Tax.-- ``(1) Liability.--The tax imposed by subsection (a) shall be paid by the shipper. ``(2) Time of imposition.--Except as otherwise provided by regulations, the tax imposed by subsection (a) shall be imposed-- ``(A) at the time of exportation in the case of a use described in subsection (d)(1), and ``(B) at the time of entry in the case of a use in subsection (d)(2). ``(d) Taxable Container Use.--For purposes of this section, the term `taxable container use' means-- ``(1) the loading of a container containing commercial cargo on a commercial vessel at a port if-- ``(A) such cargo is being exported from the United States, and ``(B) such vessel is to provide the transport from the United States, and ``(2) the unloading of a container containing commercial cargo from a commercial vessel at a port if such cargo is being entered into the United States. ``(e) Other Definitions.--For purposes of this section-- ``(1) In general.--The terms `commercial cargo', `commercial vessel', and `port' have the respective meanings given such terms under section 4462. ``(2) United states.--The term `United States' includes the possessions of the United States. ``(f) Special Rules.--Rules similar to the rules of subsections (d), (e), (f), (h), and (i) of section 4462 shall apply for purposes of this section.'' (b) Clerical Amendment.--The table of subchapters for chapter 36 of such Code is amended by inserting after the item relating to subchapter B the following new item: ``Subchapter C. Containers used to import or export cargo.'' (c) Effective Date.--The amendments made by this section shall take effect on January 1, 1996. SEC. 4. MARITIME TRUST FUND. (a) In General.--Subchapter A of chapter 98 of the Internal Revenue Code of 1986 (relating to trust fund code) is amended by adding at the end thereof the following new section: ``SEC. 9512. MARITIME TRUST FUND. ``(a) Creation of Trust Fund.--There is established in the Treasury of the United States a trust fund to be known as the `Maritime Trust Fund', consisting of such amounts as may be appropriated or credited to such Trust Fund as provided in this section or section 9602(b). ``(b) Transfers to Trust Fund.-- ``(1) In general.--There are hereby appropriated to the Maritime Trust Fund amounts equivalent to the net revenues received in the Treasury from the maritime taxes. ``(2) Net revenues.--For purposes of paragraph (1), the term `net revenues' means the amount estimated by the Secretary based on the excess of-- ``(A) the maritime taxes received in the Treasury, over ``(B) the decrease in the tax imposed by chapter 1 resulting from the maritime taxes. ``(3) Maritime taxes.--For purposes of this subsection, the term `maritime taxes' means-- ``(A) the taxes imposed by section 4471 (relating to transportation of passengers by water) to the extent the taxes received in the Treasury under such section exceed the amount that the Secretary estimates would have been received under such section without regard to the amendments made by the Maritime Trust Fund Act, and ``(B) the taxes imposed by section 4476 (relating to containers used to import or export commercial cargo). ``(c) Expenditures From Trust Fund.--Amounts in the Maritime Trust Fund shall be available, as provided in appropriation Acts, only for purposes of making expenditures to carry out any law which is substantially similar to the title IV of the Merchant Marine Act, 1936 (46 App. U.S.C. 1171) proposed to be added by H.R. 2151 (The Maritime Security and Competitiveness Act of 1993) of the 103d Congress, as introduced.'' (b) Clerical Amendment.--The table of sections for such subchapter A is amended by adding at the end thereof the following new item: ``Sec. 9512. Maritime Trust Fund.''

Maritime Trust Fund Act - Amends the Internal Revenue Code to increase the tax on transportation of passengers by water on a covered voyage to five percent of the amount paid by each passenger. (Currently, such tax is three dollars per passenger). Requires such voyages to have a port of call not located in the United States or its possessions. Imposes an excise tax on the loading of certain containers used to import or export commercial cargo on commercial vessels. Establishes the Maritime Trust Fund consisting of the maritime taxes imposed by this Act. Requires such Fund to support the maritime security fleet proposed by the Maritime Security and Competitiveness Act of 1993.

SECTION 1. NONREDUCTION IN PAY WHILE FEDERAL EMPLOYEE IS PERFORMING ACTIVE SERVICE IN THE UNIFORMED SERVICES OR NATIONAL GUARD. (a) Short Title.--This Act may be cited as the ``Reservists Pay Security Act of 2005''. (b) In General.--Subchapter IV of chapter 55 of title 5, United States Code, is amended by adding at the end the following: ``Sec. 5538. Nonreduction in pay while serving in the uniformed services or National Guard ``(a) An employee who is absent from a position of employment with the Federal Government in order to perform active duty in the uniformed services pursuant to a call or order to active duty under a provision of law referred to in section 101(a)(13)(B) of title 10 shall be entitled, while serving on active duty, to receive, for each pay period described in subsection (b), an amount equal to the amount by which-- ``(1) the amount of basic pay which would otherwise have been payable to such employee for such pay period if such employee's civilian employment with the Government had not been interrupted by that service, exceeds (if at all) ``(2) the amount of pay and allowances which (as determined under subsection (d))-- ``(A) is payable to such employee for that service; and ``(B) is allocable to such pay period. ``(b)(1) Amounts under this section shall be payable with respect to each pay period (which would otherwise apply if the employee's civilian employment had not been interrupted)-- ``(A) during which such employee is entitled to reemployment rights under chapter 43 of title 38 with respect to the position from which such employee is absent (as referred to in subsection (a)); and ``(B) for which such employee does not otherwise receive basic pay (including by taking any annual, military, or other paid leave) to which such employee is entitled by virtue of such employee's civilian employment with the Government. ``(2) For purposes of this section, the period during which an employee is entitled to reemployment rights under chapter 43 of title 38-- ``(A) shall be determined disregarding the provisions of section 4312(d) of title 38; and ``(B) shall include any period of time specified in section 4312(e) of title 38 within which an employee may report or apply for employment or reemployment following completion of service on active duty to which called or ordered as described in subsection (a). ``(c) Any amount payable under this section to an employee shall be paid-- ``(1) by such employee's employing agency; ``(2) from the appropriation or fund which would be used to pay the employee if such employee were in a pay status; and ``(3) to the extent practicable, at the same time and in the same manner as would basic pay if such employee's civilian employment had not been interrupted. ``(d) The Office of Personnel Management shall, in consultation with Secretary of Defense, prescribe any regulations necessary to carry out the preceding provisions of this section. ``(e)(1) The head of each agency referred to in section 2302(a)(2)(C)(ii) shall, in consultation with the Office, prescribe procedures to ensure that the rights under this section apply to the employees of such agency. ``(2) The Administrator of the Federal Aviation Administration shall, in consultation with the Office, prescribe procedures to ensure that the rights under this section apply to the employees of that agency. ``(f) For purposes of this section-- ``(1) the terms `employee', `Federal Government', and `uniformed services' have the same respective meanings as given them in section 4303 of title 38; ``(2) the term `employing agency', as used with respect to an employee entitled to any payments under this section, means the agency or other entity of the Government (including an agency referred to in section 2302(a)(2)(C)(ii)) with respect to which such employee has reemployment rights under chapter 43 of title 38; and ``(3) the term `basic pay' includes any amount payable under section 5304.''. (c) Clerical Amendment.--The table of sections for chapter 55 of title 5, United States Code, is amended by inserting after the item relating to section 5537 the following: ``5538. Nonreduction in pay while serving in the uniformed services or National Guard.''. (d) Effective Date.-- (1) In general.--The amendments made by this section shall apply with respect to pay periods (as described in section 5538(b) of title 5, United States Code, as amended by this section) beginning on or after the date of enactment of this Act. (2) Conditional retroactive application.-- (A) In general.--The amendments made by this section shall apply with respect to pay periods (as described in section 5538(b) of title 5, United States Code, as amended by this section) beginning on or after October 11, 2002 through the date of enactment of this Act, subject to the availability of appropriations. (B) Authorization of appropriations.--There are authorized to be appropriated $125,000,000 for purposes of subparagraph (A).

Reservists Pay Security Act of 2005 - Entitles Federal employees who are absent from their positions while on active duty in the uniformed services or the National Guard to receive the amount of their basic pay which, when taken together with their military pay and allowances, is no less than the amount of pay that they would have earned if there had been no interruption in their civilian employment. Expands the reemployment rights of Federal employees on active duty in the uniformed services. Makes this Act retroactive to pay periods beginning on October 11, 2002, subject to the availability of appropriated funds.

a 12-month - old boy was admitted to the hospital because of recurrent pulmonary infection and combined severe respiratory distress . the patient had already been diagnosed with congenital pulmonary agenesis on the right side based on pre - natal ultrasonography and a postnatal computed tomography ( ct ) scan . after admission , a follow - up ct scan and bronchoscopy were performed to evaluate the condition of the lung and trachea and their relationship with surrounding structures . bronchoscopy found tracheal narrowing at the level of the aortic arch , and chest ct confirmed that the trachea was compressed between the aortic arch and the spine . the cause of tracheal stenosis was mediastinal deviation that developed due to congenital lung agenesis ( fig . the operation was performed under general anesthesia , with the patient in the left lateral decubitus position . posterolateral thoracotomy was performed at the level of the sixth intercostal space ( ics ) , and an additional mini - thoracotomy incision was made at the level of the ninth ics to facilitate identification of the margin of the diaphragm . we approached the thorax through the extrapleural space . upon evaluation of the pleural space , the parietal pleura and mediastinal pleura were found to be intact , although no structure was associated with the lung and bronchus in the pleural space . the diaphragm was detached along the costal margin , from the sternum to the spine . the peritoneum was preserved in the costal area ; however , around the tendinous portion of the diaphragm , the peritoneum needed to be dissected for sufficient mobilization of the diaphragm . several interrupted prolene sutures reinforced with pledgets were applied to anchor the harvested diaphragm to the chest wall . the diaphragm was fixed at the level of the third rib laterally , at the level of the fourth rib anteriorly , and to the adjacent ribs posteriorly to achieve tension - free attachment of the diaphragm ( fig . finally , two separate soft drains were inserted into the pleural cavity and peritoneal cavity . the patient was transferred to an intensive care unit ( icu ) with mechanical ventilation because he had suffered severe preoperative respiratory distress due to a large volume of secretions . the following day , the patient was extubated and the drains were removed at postoperative day 12 . the postoperative course was favorable ; however , bronchitis developed and the patient suffered from a large amount of sputum and mild dyspnea . the patient received conservative care at the icu and was transferred to a general ward at postoperative day 7 . a follow - up ct scan performed on postoperative day 14 revealed improved mediastinal and tracheal deviation . furthermore , because of the rearrangement of the mediastinal structure , tracheal narrowing seemed to have improved . the patient underwent follow - up at the out - patient department until 1 year after surgery . a follow - up ct scan and bronchoscopy revealed improvement of the tracheal narrowing ( fig . congenital lung agenesis is defined as the absence of the lung and pulmonary vasculature on the affected side with preservation of the carina and main - stem bronchus . in this condition , mediastinal deviation can progress to the diseased side , which can cause kinking of the great vessels and trachea . furthermore , as mediastinal deviation develops , air trapping in the contralateral lung and severe respiratory distress can occur due to the tracheal abnormality . moreover , recurrent infections such as pneumonia or bronchitis may cause retention of bronchial secretions , and as a result , respiratory distress worsens and may lead to mortality . numerous medical treatments for repeated respiratory infections and distress have been applied , such as ventilator management , extracorporeal membrane oxygenation , and appropriate antibiotic management , all of which control respiratory infection . in 1995 , becmeur et al . attempted to reduce mediastinal deviation surgically for the first time . an inflatable prosthesis was inserted into the diseased pleural cavity . however , the patient suffered severe scoliosis until the prosthesis was removed . another surgical attempt was made to reduce secondary problems arising from mediastinal shifting , such as extrinsic tracheal compression or kinking . performed aortopexy and its result was favorable . however , in patients with this condition , such as those with pulmonary agenesis , pulmonary aplasia , or postpneumonectomy syndrome , the left main bronchus is compressed between the right main pulmonary artery , vertebral column , and aorta . aortopexy only relieves compression by the aorta and can not change the underlying condition of mediastinal shifting ; therefore , relapse is a considerable problem as patients mature . moreover , hyperinflation , which is a result of mediastinal deviation and air trapping distal to the compressed bronchus that can not be repaired by aortopexy , is another problem that compromises functional status . diaphragm translocation was first attempted by krivchenya et al . in 1995 , and the results of this operation were published in 2000 . the diaphragm was translocated in the cephalad direction to reduce the empty hemithorax cavity , and the result seemed favorable . we also considered aortopexy and prosthesis implantation ; however , we decided to perform diaphragm translocation because the patient was only 1 year old , and the growth potential of the patient might be an important factor in ensuring good long - term results . the outcome appeared to be satisfactory as of the last follow - up . to our knowledge , this is the first case of diaphragm translocation in korea . in conclusion , we report a case of pulmonary agenesis , which was successfully treated by diaphragm translocation . to further verify the feasibility and reproducibility of diaphragm translocation , reports of a larger number of patients with long - term follow - up will be required .

a 12-month - old boy was diagnosed with agenesis of the right lung . mediastinal deviation progressed to the diseased side as the patient matured ; therefore , tracheal distortion developed . as a result , tracheal compression developed between the vertebral body and aorta . the patient was repeatedly admitted to the hospital because of recurrent pulmonary infection and combined severe respiratory distress . diaphragm translocation was performed to treat the patient . the postoperative course was favorable , and computed tomography scan findings and symptoms had improved at 1 year after surgery .

in the context of climate change , an intensely debated question is whether the statistics of extreme meteo - climatic events is changing ( and/or will change ) and , in case , how fast it is changing ( and/or will change ) . for example , the role of time - dependence in the statistics of extreme weather events has been at the heart of discussions about climate change since the work by @xcite . in particular , the detection of trends in the frequency of intense precipitation has been the object of much research , particularly at regional level , see _ e.g. _ @xcite for the usa and @xcite for the mediterranean area . the general relevance of the problem has been highlighted in the 2002 release of a specific ipcc report on _ changes in extreme weather and climate events _ ( available at http://www.ipcc.ch/pub/support.htm ) . in fact , the emphasis laid on the subject by the ipcc report reverberated in many countries the question `` is the probability of major impact weather increasing ? '' . this question reached the big public almost everywhere and innumerable studies of trends in series of `` extremes '' were undertaken . these studies mainly deal with variables of _ local character _ , typically precipitation and temperature at specific stations . moreover , most studies are regional : see _ e.g. _ the proceedings of the italia - usa meeting held in bologna in 2004 @xcite for the relevance of the extreme events in the mediterranean climates and the interreg iiib - cadses project hydrocare , ` http://www.hydrocare-cadses.net ` , for impacts of extreme events in the hydrological cycle of the central - eastern europe . in a preceding , companion paper @xcite ( which we refer to by part i in the sequel ) we have addressed the problem of extreme value statistical inference on statistically _ stationary _ time series produced by a dynamical system providing a minimal model for the dynamics of the mid - latitudes baroclinic jet . there reported is , from mathematical literature , a suitable , rigorous , `` universal '' setting for the analysis of the extreme events in stationary time series . this is based on gnedenko s theorem @xcite according to which the distribution of the block - maxima of a sample of independent identically distributed variables converges , under fairly mild assumptions , to a member of a three - real parameter family of distributions , the so - called generalized extreme value ( gev ) distribution @xcite . the gev approach to the analysis of extremse requires that three basic conditions are met , namely the _ independence _ of the selected extreme values , the consideration of a _ sufficiently large _ number of extremes , the selection of values that are _ genuinely _ extreme . this could be performed relatively easily for the case at hand . part i was originally motivated by the interest in weather having `` major impact '' ( on human life and property ) in the mediterranean area , in particular intense precipitation and heat waves over italy . see , for example , @xcite and the medex phase 1 report ( available at ` http://medex.inm.uib.es/ ` ) for related results and activities . the study reported in part i has revealed , among other things , that diagnostics of extreme statistics can highlight interesting dynamical properties of the analyzed system . properties which , thanks to the `` universality of the gev '' , can be investigated in a low dimensionality space of parametric probability density functions , although at the expenses of the total length of the observational record of the system in order to capture a sufficient number of independent extremes . a key role ( that is presently being explored elsewhere , in the context of general atmospheric circulation theory ) was played in part i by the smoothness of variation of the extreme statistics parameters ( average , variance , shape factor ) upon the external ( forcing ) parameters of the system . in this paper , again , we devote attention to exploring the statistics of extremes as a dynamical indicator , this time in the framework of the ( typically meteorological ) statistical inference problem of detecting trends in observations . the definition of a rigorous approach to the study of extremes is much harder when the property of stationarity does not hold . one basic reason is that there exists no universal theory of extreme values ( such as _ e.g. _ a generalization of gnedenko s theorem ) for non - stationary stochastic processes . moreover , in the analysis of observed or synthetically generated sequences of data of finite length , practical issues , such as the possibility of unambiguously choosing the time scales which defines the statistical properties and their changes , become of critical importance . nevertheless , gev - based statistical modeling offers a practical unified framework also for the study of extremes in non - stationary time series . in the applications , the three parameters of the gev distribution are taken as time - dependent and time is introduced as a covariate in the statistical inference procedure @xcite . the practical meaning of this assumption is that the probability of occurrence ( chance ) of the considered extreme events evolves in time pretty much as we are inclined to think in our everyday life . however , giving a scientific meaning to such an assumption is possible only in an intuitive , heuristical fashion : in an `` adiabatic '' limit of infinitely slow trends ( but rigorously not even in such a limit ) . we adopt this point of view not only because it is in line with the common practice and view of extremes , but also because interesting dynamical properties can be inferred from extremes , in analogy with the findings in part i. in the present paper we perform and assess time - dependent gev inference on non - stationary time series @xmath6 of the total energy obtained by the same simplified quasi - geostrophic model that was used in part i. the model undergoes baroclinic forcing towards a given latitudinal temperature profile controlled by the forced equator - to - pole temperature difference @xmath0 ; see @xcite for a thorough description . we analyze how the parameters of the gev change with time when a linear trend is imposed on the large scale macroscopic forcing @xmath0 , that is , when @xmath0 is taken as a ( linear ) function of time . since this functional relation is invertible , we derive a parametrization relating the changes in the gev to variations in @xmath0 ( instead of time ) . one major goal here is to present a methodological framework to be adopted with more complex models and with data coming from observations , as well as an assessment of the performance of the gev approach for the analysis of trends in extremes in the somewhat _ grey area _ of non - stationary time series . methodologically , our set - up is somewhat similar to that of @xcite regarding the procedures of statistical inference . however , in this case we face two additional problems : 1 . as in part i , the statistical properties of the time series @xmath6 can not be selected _ a priori _ : in the stationary case ( @xmath0 constant in time ) and much less in the non - stationary case there is no explicit formula for the probability distribution of the observable @xmath6 ; 2 . moreover , in the non - stationary case we even lack a _ definition _ ( and in fact a mere _ candidate _ ) of what might be the probability distribution of @xmath6 : certainly not a frequency limit for @xmath7 ( and not by construction , as opposed to @xcite who use genuinely stochastic generators ) . this also means that we have no hypothesis concerning the functional form of the trend in the statistics of extremes of @xmath6 , resulting from the trend imposed on the control parameter @xmath0 . the lack of a general gev theorem for non - stationary sequences implies that the choice of the time - dependent gev as a statistical model is , in principle , arbitrary : other models might be equally ( or better ) suitable . here comes into play the `` adiabaticity '' hypothesis mentioned above , which leads to the central statement of this paper : if the trend is sufficiently slow and if the statistical behaviour of the atmospheric model has a sufficiently regular response with respect to variations in the external parameters , the gev remains a suitable model for inference of trend in extremes . the structure of the paper follows . in sec . [ sec : gevproblems ] we describe the general problem of the characterization of statistical trends in deterministic models , with both its conceptual and practical implications . then in sec . [ sec : gevmethods ] we describe how the gev modeling can be applied to non - stationary time - series and how the quality - check of the fits is performed . in section sec . [ sec : data ] we present the time series considered in this work and the set - up of the numerical experiments performed with the atmospheric model . the inferences for various values of the trend in the forcing parameter @xmath0 are presented in sec . [ sec : gevinference ] and a sensitivity analysis is carried out in sec . [ sec : gevassess ] . comparison with the stationary case analyzed in part i is given in sec . [ sec : smooth ] . in sec . [ sec : conclusions ] , finally , we summarize the main findings of this work , highlighting the future research developments . the stochastic generator used in this paper to produce the time series is a deterministic model ( an ordinary differential equation ) , whose dynamics , for the considered range of values of @xmath0 , is chaotic in the sense that it takes place on a strange attractor @xmath8 in phase space @xcite . see @xcite for a study of the properties of this attractor , including sensitivity with respect to initial conditions . the statistical behaviour of this type of time series is determined by the sinai - ruelle - bowen ( srb ) probability measure @xmath1 @xcite : this is a borel probability measure in phase space which is invariant under the flow @xmath9 of the differential equation , is ergodic , is singular with respect to the lebesgue measure in phase space and its conditional measures along unstable manifolds are absolutely continuous , see @xcite and references therein . moreover , the srb measure is also a _ physical measure _ : there is a set @xmath10 having full lebesgue measure in a neighbourhood @xmath11 of @xmath8 such that for every continuous observable @xmath12 , we have , for every @xmath13 , the frequency - limit characterization @xmath14 existence and uniqueness of an srb measure @xmath1 have been proved only for very special classes of flows @xmath9 ( in particular , for flows that possess an axiom - a attractor , see @xcite ) . however , existence and uniqueness of @xmath1 are _ necessary _ to define a stationary stochastic process associated to an observable @xmath15 . in turn , this allows to consider a given time series of the form @xmath16 as a realization of the stationary process , justifying statistical inference on a solid theoretical basis . in part i , we conjectured existence an uniqueness of an srb measure for the atmospheric model , providing the theoretical foundation to the application of gev models in the inference of extreme values . in certain cases of non - autonomous ordinary differential equations ( for example , if the dependence on time is periodic ) , it still is possible to define , at least conceptually , what an srb measure is . however , in the present case , due to the form of time - dependence adopted for the parameter @xmath0 , the atmospheric model admits _ no invariant measure_. this means that there is no ( known ) way to associate a stochastic process to the time series of the total energy . in other words , it is even in doubt what we mean by `` statistical properties '' of the time series , since it is _ impossible _ to define a probability distribution . this conceptual problem has a very serious practical consequence : the `` operational '' definition of probability as a frequency limit ( as in ( [ eq : physical ] ) ) _ is not valid in the non - stationary case _ , since the time evolution is not a sampling of a unique probability distribution . even if one assumes the existence of a sequence of distinct probability distributions , one for each observation , one realization ( the time series ) does not contain sufficient statistical information , since each distribution is very undersampled ( with only one observation ) . despite all these problems , the results in part i suggest a framework which is , for the moment , formulated in a heuristic way . suppose you evolve an initial condition @xmath17 in phase space by the flow @xmath9 of the _ autonomous _ atmospheric model , that is the system in which @xmath0 is kept fixed to some value @xmath18 . after an initial time span ( transient ) , say for @xmath19 larger than some @xmath20 , the evolution @xmath21 may be thougth to take place on the attractor @xmath8 and time - averages of the form @xmath22 may be considered as approximations of @xmath23 which is the average of @xmath15 by the srb measure @xmath24 existing at the value @xmath25 ( the `` attractor average '' at @xmath18 ) . now suppose that at some @xmath26 the parameter @xmath0 is abruptly changed to some value @xmath27 : there will be some transient interval , call it @xmath28 $ ] , during which the evolution @xmath21 approaches the _ new _ attractor of the atmospheric model , that is the attractor existing for @xmath0 fixed at @xmath29 . after that time span , the evolution may be considered to take place on the new attractor . in our case , though @xmath0 varies continuously ( linearly ) with time , if the trend magnitude is low , then @xmath0 may be considered constant ( with good approximation ) during time spans that are sufficiently long in order to have both convergence to the `` new '' attractor and good sampling of the `` new '' srb measure , in the sense sketched above . though admittedly heuristic , this scenario allows to clarify under which condition it is still reasonable to speak of `` statistical properties '' of a time series generated by a non - autonomous system : namely , the closeness to a stationary situation for time spans that are sufficiently long . this is the `` adiabatic '' hypothesis which we mentioned in the introduction . an essential ingredient for this to hold is that the statistical properties of the autonomous model _ do not sensibly depend on the external parameter @xmath0 _ , in the sense that no abrupt transitions ( bifurcations ) should take place as @xmath0 is varied . this was indeed checked for the system at hand in part i. notice that the validity of the `` adiabatic '' hypothesis also has a useful practical consequence : one can use the statistics of the stationary system as a reference against which the results for the non - stationary case can be assessed . having this scenario in mind , we proceed to the description of the time - dependent gev approach in the next section . the gev approach for sequences of independent , identically distributed ( i.i.d . ) random variables is by now rather standard @xcite . the foundation is gnedenko s theorem @xcite . consider a time series , assumed to be a realization of a sequence of i.i.d . random variables . the time series is divided into @xmath30 consecutive time - frames ( data blocks ) , each containing @xmath31 subsequent observations , equally spaced in time . denote by @xmath32 the sequence of the block maxima taken over each time - frame . under fairly mild assumptions , the distribution of the block - maxima converges , in a suitable limit involving a rescaling , to the gev distribution , defined as @xmath33^{-1/ \xi}\right\}\ ] ] for all @xmath17 in the set @xmath34 and @xmath35 otherwise , where @xmath36 and @xmath37 . if @xmath38 the limit distribution is the gumbel distribution @xmath39 gev inference consists in estimating the distributional parameters @xmath40 ( called location , scale and shape parameter , respectively ) from the available data . a widely used technique consists in numerically maximizing the _ log - likelihood _ function @xmath41 . for @xmath37 , this is defined as @xmath42 - \left [ 1 + \xi \left ( \frac{z_{t}-\mu}{\sigma } \right ) \right]^{-\frac{1}{\xi } } \right \},\end{gathered}\ ] ] while an analogous formula holds for @xmath38 @xcite . a generalization of the gev theorem holds for time series that are realizations of stationary stochastic processes such that the long - range dependence is weak at extreme levels @xcite . in the applications , this property is assumed to hold whenever the block maxima are uncorrelated for sufficiently large block sizes . in this case , gev inference and assessment is carried out by the same tools ( maximum likelihood , diagnostic plots , etc . ) used in the i.i.d . context , see @xcite . if stationarity of the time series does not hold , then the limiting distribution function is no longer bound to be the gev or any other family ( [ eq : gev ] ) : no theories of extreme values exist in this context . some exact results are known only in certain very specialized types of non - stationarity @xcite , but it is very unlikely that a general theory can be established . however , gev - based statistical modeling of extreme values can be performed also in the case of time - dependent phenomena by adopting a pragmatic approach , where the gev distribution ( [ eq : gev ] ) is used as a template : time - dependent parameters @xmath43 and @xmath44 are considered , yielding a gev model of the form @xmath45 usually @xmath3 is kept time - independent in order to avoid numerical problems , since it is usually the most delicate parameter to estimate @xcite . different kinds of time - dependence can be imposed for @xmath46 . in this paper , we adopt a simple polynomial family of models : @xmath47 with @xmath48 and @xmath49 . gev models in family ( [ eq : musigmat ] ) are denoted by @xmath50 , with @xmath51 and @xmath52 , where @xmath53 and @xmath54 denote the maximum degree of @xmath19 in @xmath43 and in @xmath44 , respectively . the time - dependent gev model ( [ eq : gevt ] ) constructed in this way is a generalization of ( [ eq : gev ] ) ( the latter is obtained by setting @xmath55 in ( [ eq : musigmat ] ) ) . for model ( [ eq : gevt ] ) with parameters ( [ eq : musigmat ] ) , gev inference amounts to estimating the parameter vector @xmath56\ ] ] by including time @xmath19 as a covariate . suppose we have a non - stationary dataset , from which a sequence of block maxima @xmath57 with @xmath58 , is constructed . a log - likelihood function for the case @xmath37 is defined as @xmath59 + \right.\\ \left . + \left [ 1 + \xi \left ( \frac{z_t -\mu(t)}{\sigma(t ) } \right ) \right]^{-1/\xi}\right\}\end{gathered}\ ] ] ( compare with ( [ eq : logllgev ] ) ) , provided that @xmath60 if @xmath38 , an alternative log - likelihood function , derived from the gumbel distribution , must be used @xcite . numerical procedures are used to maximize the selected log - likelihood function , yielding the maximum likelihood estimate of the parameter vector @xmath61 . confidence intervals for @xmath61 may be computed by the expected or observed information matrix @xcite . of course , all of the above procedure is performed in the spirit of `` pure '' inference , that is determining the likelihood of the adopted parametric hypothesis and _ not _ its truth which , in the absence of a supporting theorem , remains unknown . moreover , it should be kept in mind that several different models might fit the observations with similar reliability ( likelihood ) . in this case , as no _ universal _ model is suggested or enforced ( as opposed to the stationary case ) , there is no reason to prefer the one above the other . in the non - stationary context the analysis starts from a list of models ( @xmath50 in our case , see ( [ eq : musigmat ] ) ) which we fit to the data searching for the most adequate one . assessment and comparisons of the inferences are based on standard graphical tools such as _ probability plot , quantile plot _ , and the _ likelihood ratio test_. however , for the graphical model - checking the non - stationarity must be taken into account . reduction to _ gumbel scale _ is a practical way to treat this problem @xcite . let @xmath62 , @xmath58 be a sequence of block maxima extracted from a non - stationary time series , from which the time - dependent gev model @xmath63 has been fitted as described in the previous section . the sequence of maxima is transformed according to @xmath64 , \qquad t=1,\ldots , m.\ ] ] if @xmath65 are random variables with distribution @xmath66 , then the transformation ( [ eq : gumbelscale ] ) produces variables @xmath67 that have the standard gumbel distribution : @xmath68 which is the gev with parameters @xmath69 . therefore , transformation ( [ eq : gumbelscale ] ) attempts to remove the time - dependence from the sequence of maxima , bringing it as close as possible to the common scale given by the standard gumbel distribution ( [ eq : gumbeldf ] ) . this way , the distribution function and the quantiles of the transformed sequence of maxima @xmath70 can be compared with the empirical ones derived from ( [ eq : gumbeldf ] ) . the probability plot is a graph of the pairs @xmath71 where @xmath72 is the order statistics of the transformed sequence of maxima @xmath70 . the quantile plot is given by the pairs @xmath73 for both plots , displacement of points from the diagonal indicates low quality of the inference . the * likelihood ratio test * is used to compare the goodness - of - fit of two _ nested models _ , that is , two models such that one of them is a sub - model ( a particular case ) of the other one . our family @xmath50 of models is nested : for example @xmath74 is a sub - model of @xmath75 , obtained by setting @xmath76 and @xmath77 to zero in the parameter vector @xmath61 defined in ( [ eq : beta ] ) . given integers @xmath78 and @xmath79 , let @xmath80 and @xmath81 be the maximized values of the log - likelihood ( [ eq : logllgevt ] ) for the nested models @xmath82 and @xmath83 , respectively , and define the * deviance statistic * as @xmath84 the likelihood ratio test states that the simpler model @xmath82 is to be rejected at the @xmath85-level of confidence in favor of @xmath83 if @xmath86 , where @xmath87 is the @xmath88-quantile of the @xmath89 distribution and @xmath90 is the number of parameters that belong to @xmath83 and that are null in @xmath82 ( @xmath91 in our example above ) . although the number of time - dependent models one may choose from is virtually infinite , parsimony in the construction is reccommended @xcite : too many coefficients in the functions @xmath46 would result in unacceptably large uncertainties , especially if few data are available . the search of the best model is carried out by trial - and - error : the choice of a more complex model should be strongly justified on theoretical grounds or by a significantly higher accuracy ( that is , @xmath92 exceedingly larger than @xmath87 for nested models ) . however , the convergence of the above described procedure is _ by no means _ a guarantee of good estimate of the `` true '' probability density function : the latter is conceptually _ undefined_. see our remarks at the end of sec . [ sec : gevmethodstime ] . we consider here the same baroclinic jet model used in part i , where the spectral order @xmath93 is set to @xmath94 . the model temperature is relaxed towards a given equator - to - pole profile which acts as baroclinic forcing . the statistical properties of the model radically change when the parameter @xmath0 , determining the forced equator - to - pole temperature gradient , is varied . a physical and dynamical description of the model is given in @xcite . in part i we performed an extreme value analysis of the system s response with respect to variations in @xmath0 . several stationary time series of the total energy @xmath6 were used as a basis for gev inference . each time series was generated with @xmath0 fixed at one value within a uniform grid on the interval @xmath95 $ ] , with spacing of 2 units . we recall that , given the non - dimensionalization of the system , @xmath96 corresponds to @xmath97 , 1 unit of total energy corresponds to roughly @xmath98 , and @xmath99 is one day , see @xcite . in that case , all parameters of the system being kept fixed , after discarding an initial transient each time series of the total energy could be considered as a realization of a stationary stochastic process having weak long - range dependence . therefore , the classical framework for gev modeling was applied ( see sec . [ sec : gevmethodsstationary ] ) . in the present setting , a specific linear trend is imposed on @xmath0 : starting at time @xmath100 , the model is run with a the time - dependent forcing parameter @xmath101,\ ] ] with @xmath102 . three values are chosen for the trend intensity @xmath103 : @xmath104 units every @xmath105 @xmath106 , @xmath107 , and @xmath108 years , yielding three time series for the total energy @xmath6 . the range swept by @xmath109 during integration is kept fixed in all three cases to the interval @xmath110 $ ] , so that the total length of the time series depends on @xmath103 . each time series is split into 21 data blocks @xmath111 , @xmath112 . the length @xmath113 of each block corresponds to a time interval @xmath114 such that , as @xmath19 varies within @xmath114 , the baroclinicity parameter @xmath109 by ( [ eq : tet ] ) spans the interval @xmath115,\ ] ] which is 2 units wide and centered around one of the values @xmath116 considered in part i : @xmath117 therefore , the total length @xmath118 of the time series depends on the trend intensity , so that we have @xmath118 @xmath119 @xmath120 @xmath119 @xmath121 . moreover , since the time - span over which the maxima are computed is kept fixed to one year , the number of maxima in each data block @xmath111 also depends on @xmath103 : in fact , it is equal to @xmath113 , see tab . [ tab : data ] . such a selection of the intervals as in ( [ eq : teintervals ] ) allows for a direct comparison of the present results with those obtained for stationary time series in part i. moreover , our choices regarding block length and other factors are based on the indications provided in part i , where the goodness - of - fit assessments performed by a variety of means showed that : * the adopted block length of one year makes sure that the extremes are uncorrelated and _ genuinely extreme _ ; * the minumum length ( 100 data ) used for the sequences of maxima yields robust inferences . for each data block @xmath111 , @xmath122 , we first extract a sequence of yearly maxima @xmath123 , with @xmath124 . for compactness , each sequence is denoted in vector form as @xmath125 . one gev model of the form @xmath50 ( see ( [ eq : musigmat ] ) ) is fitted from each of the sequences @xmath126 . for each @xmath112 , the analysis follows three main steps : 1 . nested models @xmath50 , for @xmath51 and @xmath52 , are fitted on the @xmath127-th sequence of maxima @xmath126 ; 2 . models with too low maximum likelihood are discarded and the deviance test is applied to the others to select the best estimate model ; 3 . the best estimate model is graphically checked by examining the probability and quantile plots , and it is possibly rejected in favor of a model having less nonzero parameters in the vector @xmath61 as in ( [ eq : beta ] ) . following the above procedure , for each time interval @xmath114 , @xmath122 time - dependent gev models @xmath128 with parameters @xmath129 are inferred from the data block @xmath126 . model @xmath128 ( denoted for shortness @xmath130 in the rest of this section ) is the best estimate for the @xmath127-th data block , relative to the family of models @xmath50 . choosing a model with different orders @xmath131 would either give poor results in the graphical checks , or fail to pass the likelihood ratio test . an example is given in fig . [ fig : diagnotrend ] , for the data block @xmath132 in the time series with @xmath133 . the best estimate model has orders @xmath134 . models @xmath135 and @xmath75 are rejected , since they have too small likelihood and since the fit quality is very low , as it is illustrated by the probability and quantile plots . on the basis of the diagnostic plots , models @xmath74 and @xmath136 are both acceptable . however , the deviance statistic satisfies @xmath137 which is the 0.95-quantile of the @xmath138-distribution . therefore , as there is no strong support for selecting model @xmath136 , according to the likelihood ratio test the more parsimonious model @xmath74 is preferred . plots of the best estimate parameters @xmath129 as functions of time are proposed in fig . [ fig : gevtime ] . confidence intervals are computed as the _ worst case _ estimates : suppose that a model is chosen with @xmath139 , that is , for the best estimate @xmath43 is linear @xmath140 . let @xmath141 and @xmath142 be the uncertainties in @xmath143 and @xmath144 , respectively , provided by the observed information matrix ( see sec . [ sec : gevmethods ] ) . then the confidence interval at time @xmath19 is computed as @xmath145.\ ] ] for most of the time intervals @xmath114 , the best estimate model is such that @xmath146 and @xmath147 are respectively linear and constant in time , that is , @xmath134 . this is so for all models inferred with the fastest trend intensity @xmath148 ( see tab . [ tab : best100 ] ) , whereas for @xmath149 there are two exceptions : intervals @xmath150 and @xmath132 , for which also @xmath147 grows linearly in time ( @xmath151 , see tab . [ tab : best300 ] ) . for the slowest trend intensity we obtain @xmath151 for @xmath152 and zero otherwise , whereas @xmath153 for @xmath154 and @xmath155 otherwise , see tab . [ tab : best100 ] . summarizing , the best fits are mostly achieved by lowest order non - stationary models of the form @xmath134 . for slower trends , however , in some cases the best fit is of the form @xmath156 or even @xmath157 . these cases typically occur for low @xmath127 , that is , in the first portion of the time series . this is due to the fact that , for small @xmath0 ( corresponding to small @xmath19 through equation ( [ eq : tet ] ) ) , although the hypothesis of smoothness , described in sec . [ sec : gevproblems ] , may still be considered valid , the rate of variation of the srb measure with respect to variations in @xmath0 is comparatively larger . to put it in simple words , the statistical behaviour ( the attractor ) of the baroclinic model is rather sensitive with respect to changes in @xmath0 . therefore , the variation of the statistical properties in time is not quite `` adiabatic '' , in the sense specified in sec . [ sec : gevproblems ] . correspondingly , a statistical model of enhanced complexity ( more parameters ) is needed to achieve goodness - of - fit . in concluding this section , we emphasize that the convergence of the numerical procedure used in the maximization of the likelihood function is here considerably more problematic than in the stationary case studied in part i. indeed , in the present case it is often necessary to choose a good starting point for the maximization procedure in order to achieve convergence . for example , in several cases , after achieving convergence for a gev model with order , say @xmath158 , by using the inferred values of the parameter vector @xmath61 in ( [ eq : beta ] ) as starting values for the maximization , a better fit ( larger likelihood ) of _ lower order _ is obtained . in fact , this has allowed us to reduce the total number of inferences with @xmath159 and/or @xmath160 . when dealing with non - stationary data , the problem of assessing the sensitivity of trend inferences is particularly delicate . beyond the serious conceptual problems explained in sec . [ sec : gevproblems ] , one is confronted with several practical issues . most of the sensitivity tests in part i were based on examining a shorter portion of same time series or on calculating the maxima on data blocks of different lengths . in the present non - stationary context , both operations would result in an alteration of the statistical properties of the sample ( exactly because of the non - stationarity ) and this makes comparisons somewhat ambiguous . an example is provided in fig . [ fig : gevassess ] , where we compute the best estimate gev fits using sequences of yearly maxima having different lengths but starting at the same instant ( year 14500 ) extracted from the time series with the slowest trend intensity @xmath133 . notice that the best fit obtained by taking 100 yearly maxima is stationary . the corresponding extrapolations in time are , of course , completely wrong . by using 500 and 1000 maxima , the best estimates obtained ( not shown ) fall inside the confidence band of the 2000 years - based estimate for most values of time . the above example illustrates the _ trend dilemma _ : on the one hand , in order to be detected , a statistical trend has to be sufficiently fast with respect to the length of the record of observations ; on the other hand , if the trend is too fast then the `` adiabatic hypothesis '' discussed in sec . [ sec : gevproblems ] is no longer valid : one is left with no `` reference statistics '' against which the inferred models can be compared . moreover , when considering large time spans a further practical complication arises : due to the nonlinear dependence of the statistical properties with respect to the external parameter @xmath0 , a functional relation between the gev parameters and time might require many parameters to achieve goodness - of - fit . therefore , one faces the problem of large uncertainties in the parameter estimates or even lack of convergence . this has indeed been observed for the present time series : if we consider a long record , such that the change in @xmath0 is large , the model family @xmath50 with parameters as in ( [ eq : musigmat ] ) becomes inadequate to catch the time dependence of the statistics of extremes . a first indication of this was reported at the end of sec . [ sec : gevinference ] . as a further example , we have examined a data block of length 5000 starting at year 14500 in the time series with @xmath161 . inspection of graphical diagnostics ( probability and quantile plots ) reveals that no model in the family @xmath50 produces an acceptable inference . it should be emphasized that goodness - of - fit is achieved for the _ same _ time series using blocks of length 1000 , that is , performing inferences that are more localized in time . so in this case the problem is not the failure of the `` adiabatic '' or smoothness hypothesis , but the nonlinear dependence of the attractor on the parameter @xmath0 , which manifests itself on sufficiently large time intervals . the set - up of the present analysis ( see sec . [ sec : data ] ) has been chosen to allow comparison of the non - stationary gev inferences with the results of part i , obtained from statistically stationary time series . to perform the comparison , for each @xmath122 the best estimate parameters @xmath129 inferred from data block @xmath111 are first expressed as functions of @xmath0 inside the interval ( [ eq : teintervals ] ) . this is achieved by inverting the trend formula ( [ eq : tet ] ) , ( writing time as a function of @xmath0 ) : @xmath162.\ ] ] and inserting this into the expression of @xmath129 . this yields functions that are denoted as @xmath163 . these are evaluated at the central point @xmath116 of the interval of definition and plotted in fig . [ fig : gev1000 ] . confidence intervals are given by the same worst case estimate ( [ eq : worstcase ] ) used for fig . [ fig : gevtime ] . a rather smooth dependence on @xmath0 is observed , especially for the gev parameters @xmath1 and @xmath2 . the location parameter @xmath1 turns out to be not very sensitive to changes in the trend intensity , being much more sensibly dependent on variations in @xmath0 . moreover its confidence intervals are always very small ( relatively to the size of @xmath1 ) . denote by @xmath164 the time - independent gev models inferred in part i from stationary sequences @xmath165 of 1000 yearly maxima , computed with @xmath0 fixed at @xmath116 . denote as @xmath166 , @xmath167 , and @xmath168 the inferred values of the gev parameters of @xmath164 . since the graphs of the parameters @xmath166 , @xmath167 , and @xmath168 versus @xmath116 very closely match those in fig . [ fig : gev1000 ] , comparison with the stationary data is presented under the form of relative differences ( fig . [ fig : cfrgev ] ) . to be precise , on the left column the absolute values of the ratios @xmath169 are plotted against @xmath116 ( similarly for the gev parameters @xmath2 and @xmath3 ) . remarkable agreement is obtained for the parameter @xmath1 : the relative differences less than @xmath170 and drop below @xmath171 for large @xmath0 and for all considered trend intensities . excellent agreement is also obtained for @xmath2 ( particularly for large @xmath0 ) and for @xmath3 except for the fastest trend intensity @xmath103 @xmath119 @xmath172 . in the latter case , indeed , the sample uncertainty is as large as ( or even larger than ) the estimates self . we emphasize that inferring time - independent models @xmath173 from the non - stationary data @xmath126 would induce very large errors ( particularly in the scale and shape parameters ) , compare fig . [ fig : diagnotrend ] . a much better ( even surprising ) agreement between the stationary and non - stationary estimates is obtained with the procedure described in the previous section : first fitting the time - dependent model @xmath128 and then evaluating its parameters at the central point @xmath116 . there is agreement even in the estimates of the parameter @xmath3 , which is usually the most difficult one to infer . indeed , the inferred values are negative . in the case of stationary time series , since the attractor is bounded and since the energy observable @xmath6 is a continuous function of the phase space variables , the total energy is bounded on any orbit lying on ( or converging to ) the attractor . therefore , the total energy extremes are _ necessarily _ weibull distributed ( @xmath3 is negative ) part i. although this property is not bound to hold for non - stationary forcing , it is still verified , see tab . [ tab : best1000 ] . two distinct power law regimes are identified for the gev parameters @xmath174 as functions of @xmath116 , having the form @xmath175 ee fig . [ fig : powermut ] and fig . [ fig : powersigmat ] . the values of the fitted exponents @xmath176 and @xmath177 in each scaling regime are reported in tab . [ tab : powermut ] and tab . [ tab : powersigmat ] , respectively . a similar power law dependence of the gev parameters on @xmath0 was already observed in part i for the stationary data sets @xmath165 : indeed , the exponents obtained there are very similar to those in tab . [ tab : powermut ] and tab . [ tab : powersigmat ] , particularly for large @xmath0 . the lack of a power - law scaling regime for the parameter @xmath2 for small @xmath0 explains both the more pronounced differences between the stationary and non - stationary estimates ( fig . [ fig : cfrgev ] ) and the necessity of including a quadratic term in @xmath1 and/or a linear term for @xmath2 in the statistical model to get acceptable inferences . this highlights the strongly nonlinear behaviour of the baroclinic model , whose response to changes of @xmath0 has different features depending on the considered range of variation . two factors explain the qualitative analogies and the quantitative agreements between the time - dependent models discussed here and the stationary results of part i. first of all , the trend intensity imposed on @xmath0 in all cases is sufficiently slow with respect to the time of relaxation of the baroclinic model to the statistics of extreme values of the total energy . for clarity , we emphasize that the latter time scale is that used in sec . [ sec : gevproblems ] to define the `` adiabatic '' hypothesis : it is the time necessary to obtain a good sampling of the srb measure on the attractor , provided that one may consider the system as `` frozen '' ( with constant @xmath0 ) for sufficiently long time spans . we do not know whether this time scale bears any physical relation with other time scales , such as those of baroclinic instability or low - frequency variability ( both have been described in @xcite for the present model ) . the second factor is that the system s statistical behaviour responds rather smoothly to the imposed time - dependent variation of the parameter @xmath0 . this smooth dependence on @xmath0 of the statistical properties of the baroclinic model was analyzed in detail in @xcite by considering not only global physical quantities such as total energy and average wind profiles , but also finer dynamical indicators , such as the lyapunov exponents and dimension . both properties of smoothness and `` adiabaticity '' are of crucial importance in order to justify the usage of non - stationary gev models that are ( locally ) smooth functions of time , such as our polinomial family @xmath50 . in this paper we have proposed a general , although not universal , framework for the analysis of trends in extremes of climatic time series . when all the shortcomings which are present in datasets and observations have to be considered , a rigorous definition of extremes and a neat , clean , and legible approach to the evaluation of trends is necessary in order to get useful and reliable information @xcite . the time - dependent approach allows to express the inferred gev distributional parameters as functions of time . as expected , it is found that trend in the statistics of extreme values is detectable in a reliable way , provided that the record of observations is sufficiently long , depending on the time scale of the trend itself . trend inference and assessment is much more problematic than in the statistically stationary inference . first of all , one is faced with a serious conceptual problem : there is no `` operational '' definition of probability , since , to say it in loose words , the time series is not a sampling of a unique probability distribution , as it is in the stationary case . even if one assumes that the time series is a realization of a sequence of random variables ( with different distributions ) , the statistical properties of the sample are altered by any operation such as resampling or taking shorter subsamples , which makes sensitivity studies somewhat ambiguous . one must assume that the distributions of the random variables vary slowly and smoothly with time , so that the time series contains sufficient sampling information on the `` local '' ( in time ) statistical behaviour . in the present context , we have adopted gev models whose parameters are polynomial in time : the location parameter @xmath1 is at most quadratic with respect to time and the scale parameter @xmath2 is at most linear in time . since the relation between the macroscopic forcing @xmath0 and time is invertible , the time dependence of the inferred gev models can be expressed as a relation between the gev parameters and @xmath0 , showing rather interesting properties . the location and scale parameters feature power - law dependence with respect to @xmath0 , while the shape parameter has in all cases a negative value . as expected , both results are in agreement with what obtained in the companion paper ( part i ) for stationary data . since the parameter @xmath0 increases monotonically in the simulations with the baroclinic model , the system certainly does not possess any invariant measure . however , the results suggest that , as @xmath0 increases , the system explores statistical states which vary smoothly with @xmath0 and whose properties are locally quite similar to those obtained in the stationary setting . this is even captured for the relatively fast trend intensity @xmath148 . the proposed explanation is that : 1 . the system s statistical properties depend rather smoothly on @xmath0 ( also compare @xcite ) ; 2 . the adopted time - scales of variation of @xmath0 ( _ i.e. _ , the trend intensity @xmath178 ) are sufficiently slow compared to the relaxation time to the statistics of extreme values . the second condition , that was explained in more detail in sec . [ sec : gevproblems ] , amounts to the heuristic statement that for sufficiently short time spans the system s statistical properties can be considered _ frozen _ to those holding for a corresponding value of @xmath0 . the possibility of using gev models that are locally smooth ( polynomial functions of time ) depends essentially on these two conditions . for example , for a system having several bifurcations as the control parameter is changed the time - dependent gev modeling would be much more complicated . this problem is currently under investigation . however , even if the above two conditions do hold , the inference of time - dependent gev models is valid locally in time , that is , if the sequences of maxima used for the inference span not too large time periods . for large time spans , indeed , the non - linear response of the baroclinic model to variations in @xmath0 becomes dominant and polynomial gev models are no longer suitable . on the other hand , if the sequences of maxima used for the inference are too short ( depending on the trend intensity ) , wrong trend estimates may be obtained . we conclude by observing that the present and the companion paper ( part i ) are devoted not merely to the statistical inference of extremes and their trends but also to explore the possibility of using extreme statistics in diagnosing the dynamical state of a geophysical fluid . our analysis of the problem reveals , in fact , that diagnostics which is based on `` universal '' ( gev theorem ) , robust ( smoothness properties ) , simple ( power - law scaling ) , controllable ( low - dimensional parametric ) statistical models can help very much in setting up well targeted models of the general circulation , see @xcite . there are several ways in which we plan to extend the present study . first of all , we have considered a rather global indicator , the total energy of the system . other choices might be to analyze the wave kinetic energy , the available energy or also the maximum vorticity on the domain of the model , which might behave differently as @xmath0 is changed . moreover , there are delicate issues connected with reducing the scale from a global indicator to a local one , such as the value of the wind on a grid point . this brings into play all complications due to the multifractality and the spatial dependence of the process . a further development of the present work is the usage of extreme statistics as a dynamical indicator , in the sense of _ process oriented metrics _ @xcite . all these issues are currently under investigation . the authors are indebted to nazario tartaglione for useful conversations . this work has been supported by miur prin grant `` gli estremi meteo - climatici nellarea mediterranea : propriet statistiche e dinamiche '' , italy , 2003 . felici , m. , v. lucarini , a. speranza , and r. vitolo , 2006 : extreme value statistics of the total energy in an intermediate complexity model of the mid - latitude atmospheric jet . part i : stationary case . to appear in _ j. atmos . _ ( 2006 ) . lucarini , v. , s. calmanti , a. dellaquila , p. m. ruti , and a. speranza , 2006 : intercomparison of the northern hemisphere winter mid - latitude atmospheric variability of the ipcc models . _ preprint _ ` arxiv , doi : physics/0601117 ` . lucarini , v. , a. speranza , and r. vitolo , 2006 : physical and mathematical properties of a quasi - geostrophic model of intermediate complexity of the mid - latitudes atmospheric circulation . _ preprint _ ` arxiv , doi : physics/0511208 ` . v. lucarini , a. speranza , r. vitolo : self - scaling of the statistical properties of a minimal model of the atmospheric circulation , to appear in _ 20 years of nonlinear dynamics in geosciences _ , eds . j. elsner , a. tsonis , springer ( new york , usa ) ( 2006 ) . speranza , a. , a. delitala , r. deidda , s. corsini , g. monacelli , b. bonaccorso , a. buzzi , a. cancelliere , m. fiorentino , g. rossi , p. ruti , f. siccardi , 2006 : estremi nelle scienze ambientali . _ lacqua _ , * 3/2006 * , 1930 . tartaglione , n. , a. speranza , f. dalan , t. nanni , m. brunetti , and m. maugeri , 2006 : the mobility of atlantic baric depressions leading to intense precipitation over italy : a preliminary statistical analysis . accepted for publication in _ natural hazards and earth system science _ ( 2006 ) . watson , r.t . , and the core writing team , eds . , 2001 : _ climate change 2001 : synthesis report . a contribution of working groups i , ii , and iii to the third assessment report of the intergovernmental panel on climate change . _ cambridge university press , 398 pp . [ available at http://www.ipcc.ch ] .

a baroclinic model for the atmospheric jet at middle - latitudes is used as a stochastic generator of non - stationary time series of the total energy of the system . a linear time trend is imposed on the parameter @xmath0 , descriptive of the forced equator - to - pole temperature gradient and responsible for setting the average baroclinicity in the model . the focus lies on establishing a theoretically sound framework for the detection and assessment of trend at extreme values of the generated time series . this problem is dealt with by fitting time - dependent generalized extreme value ( gev ) models to sequences of yearly maxima of the total energy . a family of gev models is used in which the location @xmath1 and scale parameters @xmath2 depend quadratically and linearly on time , respectively , while the shape parameter @xmath3 is kept constant . from this family , a model is selected by using diagnostic graphical tools , such as probability and quantile plots , and by means of the likelihood ratio test . the inferred location and scale parameters are found to depend in a rather smooth way on time and , therefore , on @xmath0 . in particular , power - law dependences of @xmath1 and @xmath2 on @xmath0 are obtained , in analogy with the results of a previous work where the same baroclinic model was run with fixed values of @xmath0 spanning the same range as in this case . it is emphasized under which conditions the adopted approach is valid . _ @xmath4 pasef physics and applied statistics of earth fluids , + dipartimento di matematica ed informatica , universit di camerino + @xmath5 dipartimento di matematica u. dini , universit di firenze _ pacs : 02.50.tt , 02.70.-c , 47.11.-j , 92.60.bh , 92.70.gt

the belief that cancer cells are the sole dictators of their proliferative , invasive and migratory abilities has been revised . in its place is the view that the six hallmarks of cancer cells , namely self - sufficiency in growth signals , insensitivity to antigrowth signals and self - renewal , evasion of apoptosis , limitless replication potential , angiogenesis , invasion and metastasis , result from heterotypic signaling of cancer cells with its microenvironment . carcinoma progression and prognosis are dependent on the interaction of cancer epithelial cells with , and the recruitment of , tumor stroma , immune cells , and vascular networks as well as the alteration of the extracellular matrix [ ecm ] components ( reviewed in [ 24 ] ) . how do cancer cells influence normal cells to abandon their homeostatic activities and instead support the neoplastic nature of the tumor ? obviously , there must be some method of communication between the cancer cells and their microenvironment . the dynamic crosstalk between cancer cells and normal cells in the microenvironment is a crucial point in the progression of disease . one manner of cell - cell communication is through the secretion of molecules and paracrine signaling . molecules of secretion are no longer limited to cytokines , chemokines , growth factors , and other protein molecules but now include mirna species . mirnas are pleiotropic regulators of gene expression that regulate various normal cellular processes as well as play a role in disease progression , especially cancer . some intracellular and circulating mirna species are dysregulated in cancer , leading to altered expression that in some cases has been correlated with clinical outcomes for patients . furthermore , a number of recent studies have investigated the use of mirnas as noninvasive biomarkers for cancer diagnosis and prognosis . however , the understanding of the cellular consequences in the microenvironment of these differentially expressed mirnas is just beginning to be elucidated . in this paper , we will specifically focus on carcinomas and mirna regulation of the associated microenvironments including the tumor stroma , ecm components , and hypoxia . the tumor stroma is composed of a number of different cell types including fibroblasts , myofibroblasts , adipocytes , endothelial cells , pericytes , and immune cells . the tumor stroma is essential not only in the survival of neoplasms but the ability of these tumors to evolve invasiveness and metastatic ability . early studies appeared to indicate that cancer - associated fibroblasts ( caf ) also accumulated genetic mutations much like neoplastic cells [ 58 ] . however , further research has revealed that mutations in cafs are rare events indicating that other manners of altering gene expression profiles in these cells must exist [ 9 , 10 ] . a possible emerging mechanism for the control of gene expression within the tumor stroma by the cancer epithelium is the differential expression and transfer of mirna species ( summarized in table 1 ) . five independent fibroblast cell lines were established from invasive bladder cancer and compared to normal bladder and foreskin fibroblasts in a mirna microarray and validated in quantitative polymerase chain reaction ( qpcr ) assays . these studies observed an increase in mir-16 and mir-320 in cafs in comparison to normal bladder fibroblasts . surprisingly , mirnas such as mir-16 and mir-320 have been indicated to function in a tumor suppressor manner and shown to be downregulated in certain cancers . the low expression of mir-16 and mir-320 in colorectal and pancreatic cancers [ 12 , 13 ] is believed to be involved in cell proliferation . the identification of these upregulated mirnas in cafs may indicate an initial compensatory response by the cafs in an attempt to block cellular proliferation . alternatively , it is possible that the upregulated mirnas in cafs facilitate tumor survival or progression . additional investigations are necessary to determine the potential consequences of mirnas upregulated in one cell population and downregulated in another within a tumor . in contrast to the upregulated mirnas , mir-143 and mir-145 are downregulated in cafs compared to foreskin fibroblasts . there was no significant decrease in mir-143 and mir-145 between cafs and normal bladder fibroblasts , however , although a trend was reported . mir-143 and mir-145 are located on chromosome 5 approximately 1.3 kb apart and are most likely transcribed as a cluster ; therefore , it is not surprising that similar trends are observed . previous studies in bladder cancer have shown decreased levels of mir-145 correlated with a decrease in apoptotic ability suggesting that a decrease in mir-145 in cafs may also contribute to evasion of apoptosis in the microenvironment [ 1517 ] . a similar correlation with mir-143 has not been reported . another study looking at ten different caf cell lines from endometrial cancers identified eleven differentially expressed mirnas in the cafs in comparison to normal fibroblasts . of these eleven mirnas identified in microarrays , five were validated as statistically significant in qpcr . these included increased expression of mir-503 and mir-424 , which are present in a cluster of mirnas found on chromosomal location xq26.3 . one mirna , mir-31 , was shown to be downregulated in 9 out of 10 caf cell lines . in addition to qpcr validation of mirna species , these five mirnas were shown to have significant negative correlation with their targets genes in microarray analysis of total rna from cafs . for mir-31 , 39 targets were identified as predicted upregulated proteins in these cell lines , while for the mir-503 and mir-424 cluster , 139 combined protein targets were predicted to be downregulated . this correlation provides additional evidence suggesting a functionally important role of these mirnas in caf gene regulation . further analysis of mir-31 demonstrated that a number of the predicted target genes for mir-31 are involved in cellular movement . proteins related to transcriptional control found to be overexpressed included ccnj , elavl1 , and eny2 . genes involved in cellular movement and transport correlated to lower levels of mir-31 ; they included rhobtb1 and clasp2 involved in cytoskeletal organization , vamp4 in endosomal transport and stx12 in phagocytosis . a gene functioning in cellular transformation and anchorage - independence , tacc2 , is also a putative target of mir-31 . satb2 demonstrated the greatest fold induction of protein in these cells and is known to function in chromatin remodeling and transcription regulation . direct evidence of satb2 as a target for mir-31 was provided through luciferase reporter assays ( figure 1 ) . when conditioned media from fibroblasts overexpressing mir-31 was incubated with endometrial carcinoma cells , their migration and invasion potential was decreased although there was no effect on cell proliferation . the opposite was observed when satb2 was overexpressed in these cells indicative of a direct role of mir-31 dysregulation in tumor stromal cells and the progression of carcinomas . taken together , these induced genes can provide cafs with some of the hallmarks of cancer cells such as anchorage - independence and enhanced cellular movement and as such potentially serve as a means by which cafs act as support cells to the carcinoma . however , there is some conflicting evidence on the role of mir-31 in carcinomas . upregulation of this mirna was found in colon cancer [ 1922 ] and squamous cell carcinomas of the tongue . interestingly , in colon cancer studies not only was mir-31 upregulated but this upregulation was found to be associated with poorer clinical outcomes and increased invasiveness . although this seems like a potential contradiction for the role of mir-31 in tumor progression , an important variable between this study and that of aprilikova and colleagues is that the colon cancer study evaluated the carcinoma cells and not the supporting tumor stroma . then again , there is some support for downregulation of mir-31 in breast cancer [ 24 , 25 ] , gastric cancer , and urothelial cancers . in addition to the differences in the type of cancer under investigation in these studies , there are differences in methods used to retrieve and prepare the tissues . other details of the methods used in the various studies could also have profound effects on the data including the choice of normalizer used for quantification of the qpcr assays [ 28 , 29 ] . such contradictory reports of mir-31 expression in cancer cells and the microenvironment further highlight the importance of not only identifying differential mirna expression but the elucidation of validated target genes . the previously cited investigations identified mirnas that are dysregulated in cafs and may contribute to tumor progression . these studies did not look at the effects of mirna signals from cancer epithelial cells on the tumor microenvironment . a recent study by yu and colleagues has done just that . through their evaluation of three highly invasive cell lines and four non - invasive cell lines from breast cancers , they have identified a mirna cluster , mir-17/20 , involved in heterotypic signaling . when mir-17/20 is expressed in cancer cells , their ability for migration and invasion is suppressed . in fact , when conditioned media from mir-17/20 expressing cells was incubated with the highly invasive cell line , mda - mb-231 , the ability of these cells to migrate and invade across wounds or 3d collagen gels was greatly inhibited . further analysis of the role of mir-17/20 in breast cancer cells determined that this mirna cluster was involved in the regulation of cellular secretion that altered the cellular microenvironment . when mir-17/20 levels are decreased , cancer cells increase secretion of cytokines il-8 and cxcl-1 and proteins ck8 and alpha - eno ( figure 1 ) . while secreted il-8 and cxcl-1 have direct effects on neighboring cells through interaction with their respective receptors , ck8 and alpha - eno effects are indirect as they both act on plasminogen activation [ 31 , 32 ] . the increase in plasmin from plasminogen activation is an important player in the process of ecm degradation that ultimately facilitates migration and invasion . moreover , an increase in plasminogen activation has clinical importance in breast cancer patients as it correlates with increased invasiveness and poorer prognosis . this is the first line of evidence to show that mirnas are important in heterotypic signaling in the microenvironment of the tumor and to correlate such a role to clinical outcome . this information taken together highlights the importance of determining where mirna alterations originate in tumor cells or the tumor stroma and establishing what factors are responsible for these altered mirna levels . other questions that deserve experimental attention are to evaluate both primary and metastatic tumors to determine if mirna dysregulation is sustained or only associated with tumor progression . in other words , are mirna alterations that we are currently detecting simply stills in an ever changing landscape of tumor progression ? alteration of the ecm to allow cell invasion , migration , and angiogenesis is essential for a cancer 's ability to move from a localized , primary site . it is well established that signals such as increased matrix metalloproteinases ( mmps ) or decreased tissue inhibitors of metalloproteinases ( timps ) released into the tumor microenvironment play a critical role in the reorganization of the ecm and thus contribute to cancer metastatic ability . , these functions are important not only in the release of signaling molecules from the ecm but in providing an avenue for migration , invasion , and angiogenesis . mir-21 has been shown to be a major player in such migration and invasion in multiple cancers including gliomas , cholangiocarcinomas , and breast cancers [ 24 , 3437 ] . in gliomas , mir-21 levels targets for mir-21 in these cells have identified two mmps inhibitors , reck and timp3 , that inversely correlate with the mirna ( figure 1 ) . reck is a membrane - anchorage regulator while timp3 is an ecm - bound protease inhibitor . when these proteins are downregulated in the presence of mir-21 , there is a subsequent increase in mmp activity and invasiveness of the glioma . in addition , timp3 has been previously shown to be proapoptotic so the loss of this inhibitor also allows for the evasion of apoptosis . supporting evidence for the ability of mir-21 to act as a direct inhibitor of timp3 function in contrast , although their work has demonstrated that mir-21 was upregulated in these tumors , it was not correlated with location or grade of tumor . nevertheless , there were significant increases in mir-21 expression and corresponding loss in timp3 message in all tumor cell lines evaluated although a direct role in invasiveness was not assessed in their study . although the previous studies did show a relationship between mir-21 expression and timp3 levels , none showed that mir-21 was directly inhibiting timp3 expression through binding to predicted sites in the 3utr of the transcript . luciferase reporter assays using the timp3 3utr and mir-21 showed a significant increase in activity when breast cancer cell line mda - mb-231 was transfected with both species . in addition , their work further confirmed the association between mir-21 increases , loss of timp3 , and cell invasion both in culture and in lymph node positive tissue specimens . taken together , these studies provide strong evidence for the role of mir-21 expression in altering the ecm microenvironment of cancer cells allowing invasion and metastasis . not surprisingly , other mirnas are also currently being identified as associated with ecm reorganization in relationship to cancer . much like mir-21 , mir-146b has also been demonstrated to play a role in glioma cell invasion . thus , mir-146b does not work through the suppression of ecm inhibitors but its loss allows the upregulation of mmps . direct association of mir-146b with the 3utr of mmp16 was shown to be linked with a loss of mmp expression ( figure 1 ) . when mir-146b levels are low , migration and invasion are increased in several glioma cell lines . another downregulated mirna , mir-29c , was also shown to alter the level of ecm protein in a highly invasive cancer , nasopharyngeal carcinoma . experiments using 31 tumor specimens identified mir-29c to have an approximate 5-fold decrease in relation to normal specimens . evaluation of potential targets for mir-29c revealed 10 ecm component genes to be upregulated in these same tumors . these genes included collagen types 3a1 , 4a1 , and 5a1 as well as laminin and thymine - dna glycosylase . the ecm components mentioned above have been implicated in cell migration and invasion by assisting in matrix renewal allowing for tumor mobility . in addition , increases in deposits of collagen and laminin have clinical association with metastases in a variety of solid tumors . the above data illuminate the extensive role that mirnas are predicted to have on ecm composition and remodeling during tumor progression . as evident , there are many different avenues including inhibition of timps , activation of mmps , and alteration of ecm component secretion for mirnas to promote changes in the ecm that would be beneficial to the tumor . primary tumors that have acquired altered mirna levels will utilize these changes to further their destructive migratory and invasive properties . the survival of a tumor is dependent on an hypoxic microenvironment , which increases its invasiveness and resistance to drug treatment . a signature of hypoxia - inducible mirnas has been identified which includes mir-21 , 23a , 23b , 24 , 26a , 26b , 27a , 30b , 93 , 103 , 103 , 106a , 107 , 125b , 181a , 181b , 181c , 192 , 195 , 210 , and 213 . results from other studies also found that mir-210 , 30b , 93 , and 181b were induced under hypoxic conditions [ 4345 ] . in addition , mir-429 , 498 , 572 , 563 , 637 , 628 were found to be induced during hypoxia using a different type of microarray . some mirnas are downregulated under hypoxic conditions including mir-122a , 565 , 195 , 30e-5p , 374 , 19a , 101 , 424 , 29b , 186 , 141 , 320 , 422b , and 197 in squamous cell carcinoma cells , mir-15b , 16 , 20a , 20b , 30b , and 224 in carcinoma of nasopharyngeal epithelial cells , and mir-424 in trophoblasts [ 4345 ] . there is also evidence that the response to hypoxia may be cell - specific . for example , let-7e , 7 g and 7i are hypoxia - inducible in squamous cell carcinoma , whereas let-7a , 7c , 7d , 7e , 7f , and 7 g are downregulated by hypoxia in nasopharyngeal carcinomas . further proof of cell specificity in the response to hypoxia is provided by results that showed let-7f , 7 g , and 7i have contrasting expression levels in different colon and breast cancer cell lines . most of the hypoxia inducible mirnas are also overexpressed in solid tumors suggesting that the induction of mirnas in hypoxia initiates a signaling pathway that leads to tumor survival and/or proliferation . a good example is glioblastomas , which have a hypoxic microenvironment [ 47 , 48 ] . in addition to its role in ecm modifications through the inhibition of timp3 , this overexpression also plays a role in apoptosis evasion in glioblastoma cells , suggesting a role in cell survival . therefore it is likely that the hypoxic microenvironment of glioblastomas lead to overexpression of mir-21 , which modulates expression of transcripts that are needed for the tumors survival . in another example another area that needs further investigation in order to understand how mirnas are regulating the hypoxic response and its role in cancer is identification of the targets of these regulators . bioinformatic analysis of predicted targets suggest that the hypoxic regulated mirnas may play a role in regulating apoptosis , cell proliferation , vascularization , and the response of cancer to chemotherapy . unfortunately only a few of the predicted targets have been experimentally tested ( see below ) . one example that has been tested is hmga2 ( high - mobility group a2 ) , which has been shown to play a role in how the tumor responds to chemotherapy . expression of hmga2 is reduced in a hypoxic environment and it is likely that mir-98 , let-7 g , 7e , and 7i are at least partially responsible for this regulation . more recently , it was shown that vascular endothelial growth factor ( vegf ) expression is mediated by hypoxia - inducible factor hif-1 and stat3 in a mir-20b - dependent manner in mcf-7 breast cancer cells under conditions that mimic hypoxia . the role of mir-20b in modulating vegf expression in an oxygen dependent manner was confirmed in a separate study . several studies suggest that mir-210 is key regulator of the hif response to hypoxia in cancer ( reviewed in ) . in one study , the expression of mir-210 and mir-373 overexpression of mir-210 suppressed the abundance of rad52 , which plays a role in homology - dependent repair . similarly , overexpression of mir-373 decreased rad23b , the nucleotide excision repair protein , and rad52 . under hypoxic conditions , both rad52 and rad23b there is also evidence that mir-210 plays a role in mitochondrial dysfunction in some lung cancers . mir-210 suppresses the expression of subunit d of succinate dehydrogenase complex ( sdh ) , one of the subunits of the electron transport chain complexes i and ii , and thereby activates hif-1 . in addition , mir-210 most likely decreases the expression of iscu ( iron - sulfur cluster scaffold homolog ) and cox10 ( cytochrome c oxidase assembly protein ) , two key factors of the mitochondria electron transport chain and the tricarboxylic acid cycle , during hypoxia . in contrast to the role mir-210 plays in allowing cells to survive during hypoxia , it also represses genes expressed under normoxia that are no longer needed to adapt in a hypoxic environment . because of its numerous identified roles in regulating the hypoxic response in cancer , mir-210 may be a prognostic biomarker for several cancers including pancreatic , head and neck , and renal cancer . one question that remains unanswered is whether hypoxia - inducible factors ( hif ) , the master regulators of the response to low oxygen , regulate the expression of the mirnas . the hif transcription factors contain an oxygen - regulated alpha subunit and a constitutively expressed beta subunit . under normoxic conditions , the alpha subunit is degraded . under hypoxic conditions , however , the hif is stabilized and thus regulates the transcription of numerous genes including some involved with angiogenesis , glucose metabolism , and survival , all of which are likely to play a role in cancer development . suggestive evidence that hif does regulate the transcription of hypoxia - inducible mirnas under low oxygen conditions used chromatin immunoprecipitation assays to show that hif binds to the promoters of regulated mirnas . it is unknown which factors function in regulating the mirnas that are downregulated in hypoxia . solid tumors have an irregular vasculature that creates an environment that alternates between hypoxia and reoxygenation that most likely plays an important role in the tumor 's survival . a subpopulation of cancer stem cells was identified under hypoxic and reoxygenating cycling conditions that are expected to function in relapse and metastasis by allowing new tumors to arise . the expression of mir200c , mir205 , and mir-215 is reduced under these alternating conditions in stem cells . mir-215 suppresses epithelial - mesenchymal transition ( emt ) by decreasing the expression of the mesenchymal transcription factor zeb2 and increasing the e - cadherin level . in most cases , the downregulation of particular mirnas in regulating the hypoxic response has not yet been identified . an exception to this is found in hepatocellular carcinoma tissue where the functional consequence of reducing mir-29 expression sensitized cells to apoptosis that was triggered by hypoxia , and thus it is potentially useful as a cancer therapy . one of the key issues that need to be addressed in future studies is how mirna biogenesis is regulated in the microenvironment of cancers . we are just beginning to identify the regulators of mirna biogenesis ( recently reviewed in [ 6670 ] ) . rna polymerase ii , and in some cases rna polymerase iii , transcribes the primary transcripts ( pri - micrornas ) [ 71 , 72 ] . the pri - micrornas also undergo capping , splicing , and polyadenylation and thus have many potential steps where regulation of expression might be controlled by endogenous and exogenous stimuli . it is less likely that the microrna biogenesis machinery is responsible for the differential expression of mirnas observed under hypoxic conditions since the mirna processing proteins ago2 , drosha , exp5 , dicer , and dp103 expression is unaltered in hypoxic trophoblasts . another area where more research is needed is identification of the targets of the mirnas . there are many web sites available that may be used to predict potential targets of the mirnas . it is not unusual to identify hundreds of potential targets for a particular mirna . in addition , comparison of the prediction between various web sites indicates that there is some , but not necessarily extensive , overlap between the predicted targets . thus , it remains unclear which web sites are the most useful for predicting mirna targets that will be experimentally validated . perhaps a better approach with regard to studying the targets of the mirnas is to identify mrnas and/or proteins that are dysregulated under hypoxic conditions . transcripts that are dysregulated under low oxygen and have predicted hypoxic regulated mirna binding sites are excellent candidates for further testing . further investigation is also needed to determine if there are synergistic effects of mirnas . in most studies in which the function of mirnas is assayed , one mirna at a time is either up- or downregulated . this approach will not allow the investigator to determine if the activity of each mirna has any synergistic or inhibitory impact on the other mirnas . further studies are needed in which the expression of multiple mirnas is manipulated so that the effects may be compared to the results obtained from manipulating the activity of individual mirnas . in situ carcinomas that remain localized and noninvasive at the time of diagnosis are associated with positive clinical outcomes and increased disease - free survival for patients . unfortunately , the majority of tumors at the time of diagnosis are invasive malignant tumors with a portion of these having metastasized to secondary sites decreasing patient prognosis and survival . the ability of tumor cells to accomplish this migration and invasion is dependent on cross - talk with the surrounding microenvironment . an understanding of the mechanisms by which tumor cells communicate with the microenvironment to promote cancer growth and metastasis has the promise of providing innovative avenues of therapeutic intervention . collectively , observations that mirnas act as mediators of heterotypic signaling in the tumor stroma and ecm as well as influence responses to hypoxia provide researchers with a novel target for such therapies . the use of chemopreventative measures to control the expression of mirnas in the microenvironment will be an important approach to the global control of cancer .

the neoplastic microenvironment has been recognized to play a critical role in the development of cancer . although a large body of evidence has established the importance of the cancer microenvironment , the manners of crosstalk between it and the cancer cells still remains unclear . emerging mechanisms of communication include micrornas ( mirnas ) . mirnas are small noncoding rna molecules that are involved in the posttranscriptional regulation of mrna . both intracellular and circulating mirnas are differentially expressed in cancer and some of these alterations have been correlated with clinical patient outcomes . the role of mirnas in the tumor microenvironment has only recently become a focus of research , however . in this paper , we discuss the influence of mirnas on the tumor microenvironment as it relates to cancer progression . we conclude that mirnas are a critical component in understanding invasion and metastasis of cancer cells .

amebic liver abscess ( ala ) is a common entity especially in an endemic region . it can present in a myriad fashion with various complications with significant morbidity and mortality . or may remain asymptomatic . ala as a cause of inferior vena cava ( ivc ) thrombosis is exceedingly rare . herein , we describe a successful management of a 6-year - old child with ala and ivc thrombosis with an aggressive surgical approach . a 6-year - old malnourished boy was referred with a history of fever of 1-month duration , pain in right upper abdomen , loose motions , and vomitings for 14 days . there was hepatomegaly with tenderness and guarding in the upper abdomen with ascites . on chest auscultation , an ultrasound showed a large single abscess of 94 ml in the left lobe of liver closely abutting the intra - hepatic vena cava . contrast - enhanced computed tomography of abdomen revealed left lobe liver abscess in segments ii and iii . the thrombus was visible in the middle and left hepatic veins together with a thrombus in the ivc which extended up to the right atrium [ figure 1 ] . laboratory investigations of patient contrast - enhanced computed tomography ( cect ) scan images showing ( a ) thrombus in inferior vena cava ( ivc ) , ( b ) thrombus in right atrium , ( c ) abscess in left liver lobe in reconstructed coronal section , and ( d ) abscess in left liver lobe in axial section two - dimensional - echocardiography confirmed the above findings . the patient tested positive for amebic antibody by enzyme - linked immunosorbent assay ( elisa ) test . thrombus extracted from inferior vena cava ( ivc ) and atrium the ivc was thoroughly irrigated with normal saline . after reversal of systemic heparinization , the abdomen was opened by a roof top incision and the falciform ligament was divided . the abscess was palpable in the postero - superior aspect of segment ii lying just left of the divided falciform ligament . it was adhered to the diaphragm which was dissected free and then the abscess was de - roofed . lavage was performed followed by placement of tube drain in left sub - diaphragmatic space . pus was sent for examination which failed to reveal any trophozoites on microscopic examination and was negative for pyogenic organisms . the patient is on regular follow - up and he is in good health at 6 months from the date of operation . ala occurs because of hematogenous spread of the trophozoites of entameba histolytica from the intestinal mucosa to the liver through the portal vein . ala is most common in the tropical and sub - tropical regions . in the pediatric age group , the incidence of ala is relatively rare and only 21 - 30% of liver abscesses are of amebic type . left lobe lesions are less common , accounting for only 10 - 35% of all alas . this skewed distribution is thought to be due to the greater width and the more linear course of the right branch of the portal vein . ala is usually clinically suspected in any patient with characteristic features of pain in right upper abdomen , fever , and tender hepatomegaly . diagnosis is confirmed radiologically by demonstrating a space occupying lesion in the liver supported by a positive amebic serological test . the usual course of an ala is favorable and predictable if early diagnosis and management are initiated . ivc and/or hepatic vein thrombosis are among them which are very rare and reported scarcely in the literature . the proposed mechanisms are external compression together with a contiguous spread of inflammation over the vessel wall . the resultant endotheliitis predisposes to stasis and thrombosis and this ongoing process is the cause of extension of thrombosis into the vascular system . on this backdrop , respiratory movements of the diaphragm and coughing can cause further damage to the endothelial lining of the ivc , and this may predispose to thrombus formation in this part of the ivc . ala causing ivc thrombosis and extending into the atrium has been reported in adults by a few authors . hodkinson et al . reported ivc thrombosis with atrial extension as a complication of ala in a 50-year - old patient . barcat et al . , sodhi et al . , khan et al . , and zia - ur - rehman et al . have described cases with similar presentation as ours in adults . managed it with thrombolysis alone , whereas a percutaneous drainage with pig tail was required by sodhi et al . surgical removal was resorted to by the last two authors . in our case , the distinctive points were ( i ) involvement of the left lobe , ( ii ) a prolonged trial of conservative management could not have been given , and ( iii ) precarious and close relation to the pericardium and ivc precluded us to try percutaneous drainage . hence , a laparotomy was done after thrombus extraction which resulted in a thorough and controlled drainage . to conclude , our case is the first pediatric case of ala reported in english literature , to be managed in this manner . this report highlights the importance of promptly diagnosing these exceptional cases and also emphasizes individualizing the management based on patient 's clinical profile and available multimodality expertise for optimum outcome . an early aggressive surgical approach may prove life saving and crucial in preventing pulmonary embolism or budd chiari syndrome which may have an overall poor outcome .

amebic liver abscess ( ala ) in pediatric age group is rare . we describe a successful thrombectomy and open drainage of a large left lobe ala associated with thrombus in the hepatic veins and inferior vena cava extending into the right atrium in a 6-year - old boy .

SECTION 1. SHORT TITLE. This Act may be cited as the ``Independent Office of Advocacy Act''. SEC. 2. FINDINGS. Congress finds that-- (1) excessive regulations continue to burden our Nation's small businesses; (2) Federal agencies are reluctant to comply with the requirements of chapter 6 of title 5, United States Code, and continue to propose regulations that impose disproportionate burdens on small businesses; (3) the Office of Advocacy of the Small Business Administration (referred to in this Act as the ``Office'') is an effective advocate for small businesses that can help ensure that agencies are responsive to small businesses and that agencies comply with their statutory obligations under chapter 6 of title 5, United States Code and under the Small Business Regulatory Enforcement Fairness Act of 1996 (Public Law 104- 121; 106 Stat. 4249 et seq.); (4) the independence of the Office is essential to ensure that it can serve as an effective advocate for small businesses without being restricted by the views or policies of the Small Business Administration or any other executive branch agency; (5) the Office needs sufficient resources to conduct the research required to assess effectively the impact of regulations on small businesses; and (6) the research, information, and expertise of the Office make it a valuable adviser to Congress as well as the executive branch agencies with which the Office works on behalf of small businesses. SEC. 3. PURPOSES. The purposes of this Act are-- (1) to ensure that the Office has the statutory independence and adequate financial resources to advocate for and on behalf of small business; (2) to require that the Office report to the Chairmen and Ranking Members of the Committees on Small Business of the Senate and the House of Representatives and the Administrator of the Small Business Administration in order to keep them fully and currently informed about issues and regulations affecting small businesses and the necessity for corrective action by the regulatory agency or Congress; (3) to provide a separate authorization for appropriations for the Office; (4) to authorize the Office to report to the President and to Congress regarding agency compliance with chapter 6 of title 5, United States Code; and (5) to enhance the role of the Office pursuant to chapter 6 of title 5, United States Code. SEC. 4. OFFICE OF ADVOCACY. (a) In General.--The Small Business Act (15 U.S.C. 631 et seq.) is amended-- (1) by redesignating section 32 as section 33; and (2) by inserting after section 31 the following: ``SEC. 32. OFFICE OF ADVOCACY. ``(a) Definitions.--In this section-- ``(1) the term `Chief Counsel' means the Chief Counsel for Advocacy appointed under subsection (b); and ``(2) the term `Office' means the Office of Advocacy established under subsection (b). ``(b) Establishment.-- ``(1) In general.--There is established in the Administration an Office of Advocacy (referred to in this section as the `Office'). ``(2) Chief counsel for advocacy.-- ``(A) In general.--The management of the Office shall be vested in a Chief Counsel for Advocacy who shall be appointed from civilian life by the President, by and with the advice and consent of the Senate, without regard to political affiliation and solely on the ground of fitness to perform the duties of the office. ``(B) Employment restriction.--The individual appointed to the office of Chief Counsel for Advocacy may not serve as an officer or employee of the Small Business Administration during the 5-year period preceding the appointment. ``(C) Removal.--The Chief Counsel for Advocacy may be removed from office by the President and the President shall notify Congress of any such removal not later than 30 days before the removal. ``(3) Appropriation request.--Each appropriation request prepared and submitted by the Administration under section 1108 of title 31, United States Code, shall include a separate request relating to the Office. ``(c) Primary Functions.--The Office shall-- ``(1) examine the role of small businesses in the economy of the United States and the contribution that small businesses can make in improving competition, encouraging economic and social mobility for all citizens, restraining inflation, spurring production, expanding employment opportunities, increasing productivity, promoting exports, stimulating innovation and entrepreneurship, and providing the means by which new and untested products and services can be brought to the marketplace; ``(2) assess the effectiveness of Federal subsidy and assistance programs for small businesses and the desirability of reducing the emphasis on those programs and increasing the emphasis on general assistance programs designed to benefit all small businesses; ``(3) measure the direct costs and other effects of government regulation of small businesses, and make legislative, regulatory, and nonlegislative proposals for eliminating the excessive or unnecessary regulation of small businesses; ``(4) determine the impact of the tax structure on small businesses and make legislative, regulatory, and other proposals for altering the tax structure to enable all small businesses to realize their potential for contributing to the improvement of the Nation's economic well-being; ``(5) study the ability of financial markets and institutions to meet small business credit needs and determine the impact of government demands on credit for small businesses; ``(6) determine financial resource availability and recommend methods for-- ``(A) delivery of financial assistance to minority and women-owned enterprises, including methods for securing equity capital; ``(B) generating markets for goods and services; ``(C) providing effective business education, more effective management and technical assistance, and training; and ``(D) assistance in complying with Federal, State, and local laws; ``(7) evaluate the efforts of Federal agencies and the private sector to assist minority and women-owned enterprises; ``(8) make such recommendations as may be appropriate to assist the development and strengthening of minority, women- owned, and other small businesses; ``(9) recommend specific measures for creating an environment in which all businesses will have the opportunity to-- ``(A) compete effectively and expand to their full potential; and ``(B) ascertain any common reasons for small business successes and failures; ``(10) determine the desirability of developing a set of rational, objective criteria to be used to define small business, and to develop such criteria, if appropriate; and ``(11) make recommendations and submit reports to the Chairmen and Ranking Members of the Committees on Small Business of the Senate and the House of Representatives and the Administrator with respect to issues and regulations affecting small businesses and the necessity for corrective action by the Administrator, any Federal department or agency, or Congress. ``(d) Additional Functions.--The Office shall, on a continuing basis-- ``(1) serve as a focal point for the receipt of complaints, criticisms, and suggestions concerning the policies and activities of the Administration and any other department or agency of the Federal Government that affects small businesses; ``(2) counsel small businesses on the means by which to resolve questions and problems concerning the relationship between small businesses and the Federal Government; ``(3) develop proposals for changes in the policies and activities of any agency of the Federal Government that will better fulfill the purposes of this section and communicate such proposals to the appropriate Federal agencies; ``(4) represent the views and interests of small businesses before other Federal agencies whose policies and activities may affect small business; ``(5) enlist the cooperation and assistance of public and private agencies, businesses, and other organizations in disseminating information about the programs and services provided by the Federal Government that are of benefit to small businesses, and information on the means by which small businesses can participate in or make use of such programs and services; and ``(6) carry out the responsibilities of the Office under chapter 6 of title 5, United States Code. ``(e) Staff and Powers.-- ``(1) Staff.-- ``(A) In general.--The Chief Counsel may, without regard to the civil service laws and regulations, appoint and terminate such additional personnel as may be necessary to enable the Office to perform its duties under this section. ``(B) Compensation.--The Chief Counsel may fix the compensation of personnel appointed under this paragraph without regard to the provisions of chapter 51 and subchapter III of chapter 53 of title 5, United States Code, relating to classification of positions and General Schedule pay rates, but at rates not to exceed the minimum rate payable for a position at GS-15 of the General Schedule, except that not more than 14 employees of the Office at any one time may be compensated at a rate not to exceed the maximum rate payable for a position at GS-15 of the General Schedule. ``(2) Powers.--In carrying out this section, the Chief Counsel may-- ``(A) procure temporary and intermittent services to the same extent as is authorized by section 3109 of title 5, United States Code; ``(B) consult with-- ``(i) experts and authorities in the fields of small business investment, venture capital, investment and commercial banking, and other comparable financial institutions involved in the financing of business; and ``(ii) individuals with regulatory, legal, economic, or financial expertise, including members of the academic community, and individuals who generally represent the public interest; ``(C) use the services of the National Advisory Council established under section 8(b) and, in accordance with that section, appoint such other advisory boards or committees as the Chief Counsel determines to be reasonably necessary and appropriate to carry out this section; and ``(D) hold hearings and sit and act at such times and places as the Chief Counsel determines to be appropriate. ``(f) Overhead and Administrative Support.--The Administrator shall provide the Office with appropriate and adequate office space at central and field office locations of the Administration, together with such equipment, office supplies, and communications facilities and services as may be necessary for the operation of such offices, and shall provide necessary maintenance services for such offices and the equipment and facilities located therein. ``(g) Information From Federal Agencies.--The Chief Counsel may secure directly from any Federal department or agency such information as the Chief Counsel considers to be necessary to carry out this section. Upon request of the Chief Counsel, the head of such department or agency shall furnish such information to the Office. ``(h) Reports.-- ``(1) Annual reports.--Not less than annually, the Chief Counsel shall submit to the President and to the Committees on Small Business of the Senate and the House of Representatives, the Committee on Governmental Affairs of the Senate, the Committee on Government Reform of the House of Representatives, and the Committees on the Judiciary of the Senate and the House of Representatives a report on agency compliance with chapter 6 of title 5, United States Code. ``(2) Additional reports.--In addition to the reports required under paragraph (1) of this subsection and subsection (c)(12), the Chief Counsel may prepare and publish such reports as the Chief Counsel determines to be appropriate. ``(3) Prohibition.--No report under this section shall be submitted to the Office of Management and Budget or to any other department or agency of the Federal Government for any purpose before submission of the report to the President and to Congress. ``(i) Authorization of Appropriations.-- ``(1) In general.--There are authorized to be appropriated to the Office to carry out this section such sums as may be necessary for each fiscal year. ``(2) Availability.--Any sums appropriated under paragraph (1) shall remain available, without fiscal year limitation, until expended.''. (b) Repeal.--Title II of Public Law 94-305 (15 U.S.C. 634a et seq.) is repealed. (c) Incumbent Chief Counsel for Advocacy.--The individual serving as the Chief Counsel for Advocacy of the Small Business Administration on the date of enactment of this Act shall continue to serve in that position after such date in accordance with section 32 of the Small Business Act, as amended by this section. Passed the Senate November 5, 1999. Attest: GARY SISCO, Secretary.

Directs the Chief Counsel of the Office to report at least annually to specified congressional committees on Federal agency compliance with certain small business deregulation requirements. Authorizes appropriations.

the incidence of differentiated thyroid cancer ( dtc ) has been increasing during the last few decades , mostly attributable to better detection of small papillary cancer as a result of improved diagnostic accuracy . however , improved detection does not fully explain significant increase in tumours with adverse pathologic characteristics . despite the fact that most of dtc have an indolent course with conventional therapy ( surgical treatment , ablative i131 , and suppressive treatment with l - thyroxine ) , metastatic , recurrent , and poorly differentiated tumours still represent a challenge for the clinicians . in order to improve management disease , different groups have been focused on molecular pathways involved in thyroid cancer pathogenesis , thus providing prognostic markers for well - differentiated tumours , as well as new targets for therapy . in dtc , the risk of recurrence / persistence is higher than the risk of disease - specific mortality . different staging systems ( american joint cancer committee / union internationale contre le cancer ) have been proposed to predict the risk of death . however , these systems do not predict accurately the risk of recurrence or persistent disease . the european thyroid association ( eta ) in 2006 and the american thyroid association ( ata ) in 2009 published management guidelines based on individualised risk stratification [ 4 , 5 ] . both of them incorporate data from tumour - related factors , clinical features , results of first posttherapy radioiodine whole - body scan , serum thyroglobulin ( tg ) measurement to assess the risk of recurrence and mortality , and also the need for adjuvant therapies and the early follow - up strategies . moreover , during the last few years , several authors have proposed incorporating tg determination at the time of radioiodine ablation as predictive factor for the risk of recurrence or persistence disease in the postoperative period [ 6 , 7 ] . recently , different groups have been focused on new ongoing risk stratification systems incorporating variables that assess the response to initial therapy ( rit ) . these variables modify the initial risk estimation and , therefore , are able to achieve more accurate predictions of clinical outcomes . in 2010 , tuttle et al . developed a system that included data from the first two years of follow - up , period of time in which much of the variability in outcome can be appreciated , categorizing the response to therapy into excellent , acceptable , or incomplete . an excellent response was defined as stimulated and suppressed tg < 1 ng / ml and no evidence of disease by imaging . an acceptable response was defined as suppressed tg < 1 ng / ml , the presence of low serum stimulated tg level ( 110 ng / ml ) , or the presence of nonspecific changes in neck ultrasound or nuclear medicine imaging . finally , an incomplete response was defined as suppressed tg 1 ng / ml , stimulated tg 10 ng / ml , rising tg values , or persistent / newly identified disease on imaging . the aim of our study is to compare the predictive value of the classical risk stratifications systems and the new system proposed by tuttle et al . in our population . we retrospectively reviewed 176 patients with dtc evaluated at granollers general hospital and parc taul sabadell university hospital between 2000 and 2012 . compartment - oriented microdissection of lymph nodules was performed in case of preoperative suspected or intraoperative proven lymph nodules metastases . they also underwent thyroid ablation with i and received thyrotropin - suppressive treatment with l - thyroxine ( lt4 ) . our cohort did not include patients classified as very low risk by the european system , because management guidelines do not recommend total or near - total thyroidectomy and thyroid ablation with i , making follow - up strategies impossible by tg assay and i whole body scan . we also excluded patients with inadequate follow - up information and positive anti - tg antibodies ( tgab ) interfering in the tg assessment by immunometric methods . patients were followed up every 612 months and management and follow - up protocol was based on the european consensus published in 2006 . we only included patients who had information available about results of neck ultrasound ( us ) , performed , suppressed , and stimulated tg determinations , and at least one diagnostic i whole body scan , during the first two years of follow - up . before 2002 , different tg assays were used with a functional sensitivity of approximately 1 ng / ml . starting in 2002 , all tg values were tested by solid - phase immunochemiluminometric assay with an analytical sensitivity of 0.2 ng / ml and a functional sensitivity of 0.9 ng / ml normalized to certified reference material 457 ( immulite , siemens , inc . ) . both stimulated and suppressed tg were tested by the same assay . the tgab levels were measured by immunometric assay with the lowest reportable concentration of 10 iu / ml . after initial treatment , each patient was stratified using the american joint cancer committee / union internationale contre le cancer ( ajcc / uicc ) staging system and the ata and the eta systems . all data obtained after the first whole body scan and stimulated tg was used to stratify patients into an excellent , acceptable , or incomplete response to initial therapy . at the end of the follow - up we calculated the predictive value to assess the ability of each risk stratification system for predicting the final outcome by performing 2 2 contingency tables . the negative predictive value ( npv ) was defined as the probability of being free of disease at the end of follow - up in patients who had been classified as low risk by the ata / eta systems or had presented an excellent response to initial treatment . we also calculated the positive predictive value ( ppv ) defined as the probability of persistent disease , either biochemical or structural , and disease specific - mortality , in patients who had been classified as high risk by the eta system and intermediate or high risk by the ata system or had presented an acceptable / incomplete response to initial therapy . in order to analyse the ability to predict clinical outcomes , we calculated the area under receiver operating characteristic ( roc ) curve for each risk stratification system . all data related to the epidemiological characteristics of the cohort , type of cancer , different risk stratifications , and clinical endpoints are summarized in table 2 . most patients initially considered to have low risk of persistent / recurrent disease by static staging systems had no evidence of disease at the end of the study ( 94% for eta and 94.9% for ata system ) . despite they were classified as high risk by the eta system and intermediate risk by the ata system , they still presented a high likelihood of being free of disease ( 59.7% for eta and 62.8% for ata ) . however , when patients were initially classified as high risk by the american system , most of them showed negative clinical endpoints ( 75% ) . comparing with the two staging systems , the new risk stratification system showed better predictions of the final outcome . the majority of patients classified as an excellent response showed no evidence of disease at the end of the study ( 97.7% ) . on the other hand , those who were classified as an acceptable or incomplete response to initial therapy exhibit higher probabilities of having negative clinical outcomes ( 68.5% for the acceptable response group and 72.4% for incomplete response group ) . furthermore , most patients who presented an acceptable response and had persistent disease showed persistent biochemical disease but no evidence of structural disease . all patients dying of thyroid cancer were correctly classified by the three risk stratification systems ( table 3 ) . we made 2 2 contingency tables to calculate predictive values for each risk stratification system ( table 4 ) . regarding ppv , eta and ata systems presented low ppv , 40.3% and 41% , respectively , whereas rit system showed acceptable ppv ( 70.8% ) . the negative predictive value shown by the rit system was even higher ( npv 97.7% ) than those observed for eta ( 93.9% ) and ata systems ( 94.9% ) . in order to analyse the ability to predict clinical outcomes , the area under roc curve was calculated for each risk stratification system and compared between them ( figure 1 ) . the area under roc curve was 0.7535 for eta system ( 95% ic = 0.68160.8253 ) , 0.7876 for ata system ( 95% ic = 0.71640.8587 ) , and 0.9112 for rit system ( 95% ic = 0.85840.9640 ) , showing statistical significant differences between ongoing staging system and the two static staging systems . there were no statistical significant differences between ata and eta systems ( table 5 ) . the major finding in this work suggests that the new ongoing system proposed by tuttle predicts better the final outcome than the two classical systems and is in agreement with different works published during the last few years . in 2010 , tuttle et al . compared the ability to predict the risk of recurrence / persistence disease by the rit system and the one proposed by the american association by determining the proportion of variance explained ( pve ) and showed 34% of the variance for the ata system , increasing the pve to 84% when the new system was used . they also demonstrated the impact of restratification , being more apparent in patients initially classified as intermediate risk , with a risk reduction from 18% to 2% , in those who had presented an excellent response to therapy . otherwise , patients who presented an incomplete response to therapy experienced an increase in the initial risk ( from 3% to 13% ) . castagna et al . proposed in 2011 a new staging system incorporating data at the time of the first control ( 812 months after initial therapy ) , categorizing patients into delayed risk stratification ( drs ) low - risk and drs high - risk group . they analysed the ability of each stratification system by determining the ppv and npv and observed very low ppv for both ata and eta ( 39.2% and 38.4% , resp . ) , while the npv were rather high ( 90.6% and 91.3% , resp . ) however , drs system showed significantly better predictive values than the two classical systems with a ppv of 72.8% and a npv of 96.3% . finally , in 2013 , jeon et al . incorporated the level of serum tgab in the dynamic risk stratification proposed by tuttle and compared with tnm staging and ata systems and also showed the highest pve ( 44.6% ) among the three risk stratification systems ( 8.7% for tnm staging and 12.1% for ata classification ) . in our experience , the incomplete response to initial therapy cohort includes a heterogeneous group of patients , ranging from those with only biochemical persistent disease to those with structural disease , actually exhibiting distinct prognosis . proposed subdiving the incomplete response group into biochemical incomplete response and structural incomplete response , showing that structural incomplete response was associated with higher likelihood of presenting structural evidence of disease and disease specific mortality at the end of follow - up than biochemical incomplete response alone . it would be interesting to apply this modified rit system to our cohort of 176 patients with differentiated thyroid cancer in future works . several authors have demonstrated the usefulness of the american and european systems to predict the risk of recurrence / persistent disease , basically based on initial tnm stage . however , successful ablation , established by negative serum tg and negative i diagnostic whole body scan , leads to higher probabilities of presenting favourable clinical endpoints regardless of the initial risk , thus supporting the need for new ongoing risk stratification systems . for this reason , they both constitute good systems for tailoring the intensity of initial management and follow - up strategy but lose effectiveness in predicting long - term outcomes . we consider new ongoing risk stratification systems as a complementary tool in order to individualize long - term management and follow - up strategy . for example , in high risk patients with an undetectable stimulated tg and normal findings on neck us and diagnostic i whole body scan at the 6- to 12-month follow - up , the risk of recurrence is very low . therefore , subsequent follow - up could be based on suppressed tg and neck us , avoiding additional stimulated tg and diagnostic i whole body scan , and the dose of l - thyroxine could be safely decreased with the goal of obtaining a thyrotropin level within the lower normal range . highly sensitive detection tools used in clinical practice have led to diagnose an important number of patients who have persistent evidence of small - volume disease , mostly detected by stimulated tg measurements without evidence or little structural disease . although management of these patients remains controversial , additional therapy provides no benefit in overall survival rates . therefore , we consider that most of these patients can undergo follow - up with observation alone and practice additional therapy in case of evidence of progression considering that the majority of recurrences are diagnosed during the first years after initial treatment , a median follow - up period of 7 years seems adequate , although longer studies need to be made in order to validate new dynamic staging systems . moreover , this new restratification system can only be applied in patients who underwent total or near - total thyroidectomy and thyroid ablation with i131 . management guidelines do not recommend thyroid ablation in very low risk group of the eta system and low risk patients of the ata system with unifocal cancer < 1 cm or multifocal cancer when all foci are < 1 cm in the absence of other high risk features . another limitation is the inability to diagnose recurrence / persistent disease by determining thyroglobulinemia in the presence of interfering tgab . as we mentioned previously , jeon et al . incorporated tgab levels in the dynamic risk stratification system , considering a value exceeding 60 iu / ml to be positive for interfering in tg assessment . however , in our opinion , lower tgab concentrations are able to interfere in tg assessment by immunometric methods and , although there is a drastic decrease during the first six months after surgery and it could be useful in order to detect recurrence disease , they could take longer to become undetectable . finally , limited number of patients classified as high risk by the ata system and acceptable / incomplete response by the rit system induce less consistent predictions of future outcomes in these groups ; therefore , it would be interesting to enlarge the number of patients in future works . in conclusion , in order to offer appropriate management to patients , ongoing reassessment of the risk of recurrence / persistent disease during follow - up is required . thereby , our findings provide evidence that response to initial therapy is a useful risk stratification system to adapt and modify the intensity of follow - up , avoiding unnecessary diagnostic tests in those patients who have presented an excellent response , and , on the other hand , being more aggressive in those patients who have presented an incomplete response , regardless of the initial risk .

objective . although differentiated thyroid cancer ( dtc ) usually has an indolent course , some cases show a poor prognosis ; therefore , risk stratification is required . the objective of this study is to compare the predictive ability of classical risk stratification systems proposed by the european thyroid association ( eta ) and american thyroid association ( ata ) with the system proposed by tuttle et al . in 2010 , based on the response to initial therapy ( rit ) . methods . we retrospectively reviewed 176 cases of dtc with a median follow - up period of 7.0 years . each patient was stratified using eta , ata , and rit systems . negative predictive value ( npv ) and positive predictive value ( ppv ) were determined . the area under receiver operating characteristic ( roc ) curve was calculated in order to compare the predictive ability . results . rit showed a npv of 97.7% , better than npv of eta and ata systems ( 93.9% and 94.9% , resp . ) . eta and ata systems showed poor ppv ( 40.3% and 41% , resp . ) , while rit showed a ppv of 70.8% . the area under roc curve was 0.7535 for eta , 0.7876 for ata , and 0.9112 for rit , showing statistical significant differences ( p < 0.05 ) . conclusions . rit predicts the long - term outcome of dtc better than eta / ata systems , becoming a useful system to adapt management strategies .

cellular automata ( ca ) micro - simulation has emerged as a tool for simulating traffic flow and modelling transport networks @xcite . in ca , time and space are discrete . the space is represented as a uniform lattice of cells with finite number of states , subject to a uniform set of rules , which drives the behavior of the system . these rules compute the state of a particular cell as a function of its previous state and the state of the neighboring cells . agents moving from origins to destinations across networks may represent several real entities , as for example : ants , biological organisms , small robots , transport in micro - mechanical systems , crowd flow , packets transport in the internet , etc .... it was found that the motion of the biological organisms is usually controlled by interactions with other organisms in their neighborhood and randomness also plays an important role @xcite . real ants have been shown to be able to find shortest paths towards destinations using as only information the pheromone trail deposited by other ants @xcite . the finding of shortest paths , inspired from ants behavior , are successfully applied to several physical problems such as , pedestrians @xcite , traffic flow @xcite , combinatorial optimization @xcite and circuit switched communications network problems @xcite . the problems of movement of agents with origins and destinations were studied using a two dimensional cellular automata @xcite . in these models an agent tries to reach its destination using simple rules . transitions from the freely moving to the jamming states were studied . a variant 2-dimensional ca model for simulation of agents moving from origins to destinations will be presented here . agents moving across the network have sensors to perceive their local neighborhood and their destinations and then affect their environment . this is done especially by estimating the distance metric to the destination site . the concern herein will be with the movement , propagation , and interaction of agents in low and high density situations . this will be done by exploring the patterns and behaviors of the spatio - temporal organization of agents . the objective of this research is to provide insight into modelling complex dynamics using ca microsimulation and capturing general features of agents travelling from origins to destinations . the paper is organized as follows . in sec . @xmath3 , we describe our model for movements of agents with origins and destinations . in sec . @xmath4 , we present our numerical results where we give the phase diagrams of the system . a detailed description of the cluster size and the travel time distributions are also presented . finally , we conclude with some conclusions in sec . @xmath5 . the ca model is a two - dimensional cellular automaton based on a square lattice with periodic boundary conditions . there is a fixed number of agents on the lattice at all times . only one agent at most can occupy a given site . at any time step , an agent can move at most to one of its 4 neighboring sites . updating of the ca occurs in parallel where the rules are applied to all agents at the same time . agents are associated with given origin - destination sites . the origin and destination sites must be different . an agent travels from the origin site towards its destination site , whereupon it disappears . each disappeared agent is immediately replaced by a new agent , and so the agent number is always constant in the lattice . a new origin - destination pair is then chosen randomly for this new agent . if , however , there is an agent already present at the chosen origin , then another origin site is selected . agents will move towards their destinations at all times by selecting an unoccupied neighboring site which has the minimal distance from that site to the destination site ( see figure 1 ) . an agent examines the unoccupied neighboring sites . for each of these sites a distance to the destination is evaluated . then , a site with the minimal distance is selected as the next site to which the agent will move . if all neighboring sites are occupied it will not move . the stochasticity or noise is introduced in the model dynamics , through the uncertainty in estimating the distance from the destination . so , with probability @xmath0 an agent moves towards an arbitrary empty neighboring site rather than the site of minimal distance . the friction parameter @xmath2 is also introduced to control the probability that the movement of all agents involved to the same site ( conflict ) is denied at one time step . this friction parameter which is essential for resolving the conflict arising in parallel update simulations , is applied for pedestrian traffic problems @xcite . in each time step , positions , speeds and directions of all agents are updated according to the following local rules : - with probability @xmath0 , an agent selects one arbitrary empty neighboring site . - with probability @xmath6 agent selects an empty neighboring site corresponding to the minimal distance to the destination . if two empty neighboring sites of one agent have the same minimal distance from the destination then one of these two allowed neighbors is chosen randomly . if two or more agents select the same site ( conflicts ) then : - with probability @xmath2 none of the agents is allowed to move to their selected site . - with probability @xmath7 one of these agents is chosen randomly to move to its selected site ; the others agents do not move . if there exist no conflict , the agent moves to its selected site . if all neighboring sites are occupied , the agent does not move . we carry out our computer simulations of the model by considering a square lattice of size @xmath8 with periodic boundary conditions . initially , we put randomly a number @xmath9 of agents into the lattice . the density of agents is denoted as @xmath10 . the velocity of each agent can be either 1 or 0 . the duration of each simulation run is @xmath11 time steps with the first @xmath12 time steps to initiate the simulation and the latter @xmath13 used to generate performance statistics . agents are only allowed to move to unoccupied nearest neighbor sites in one time step , i.e. @xmath14 cell / time step . in figure 2 , we carried out the plots of the mean velocity of agents as a function of the density , for several system size . hence , the plots show that @xmath15 undergoes a sudden phase transition from a freely moving state @xmath16 to jammed state @xmath17 at a critical density @xmath18 . in the freely moving state , interaction between agents is weak and the propagation is important inside the network . in contrast , for large density , the interaction becomes strong and jamming takes place where agent movements become rare . as regards the variation with system size @xmath8 , we find that the critical density decreases with increasing @xmath8 and the phase transition becomes sharper . in figure 3 , we plot @xmath19 as a function of @xmath2 for different values of @xmath0 and @xmath20 . hence , for low density , the average speed remains almost constant if the probability @xmath0 is high . however , if @xmath0 is low , @xmath15 undergoes a sudden decrease when @xmath2 exceeds a critical value @xmath21 . this corresponds to a phase transition from the freely moving state to the jamming state . consequently , the enhancement of the friction parameter can topple over from the freely moving to the jamming of agents even at low densities . at high densities , @xmath15 decreases gradually with @xmath2 for all values of @xmath0 . yet , the speed @xmath15 remains always greater for larger @xmath0 . the phase diagrams of the system is depicted in figure 4 , where we plotted the critical values @xmath21 as a function of @xmath0 for several fixed values of @xmath20 . thus , for low densities and for a given value of @xmath0 , freely moving phase should exist if @xmath22 while jamming phase takes place if @xmath23 . it was shown also from figure 4 that the jamming region is broaden as soon as the density is increased . yet , when the density exceeds some value @xmath24 , the freely moving phase should never exist . it is clear that the density dependence of speed alone , can not give the whole information on the phase behavior of the system . to get more information on the microscopic structure of the phases , one can determine the spatio - temporal organization of agents in the lattice . this microscopic investigations can be obtained by plotting the organization patterns of agents and the distributions of cluster sizes and travel times . the cluster and the cluster size mean here a connected bonds of unoccupied cells and a maximally number connected cells of agents respectively . the travel time is the time it would take to travel from the origin to destination . figures 5(a - b ) show a typical configurations of the organization of agents at low density . so , for vanished value of @xmath0 and for low values of @xmath2 , the steady state corresponds to the freely moving . however if @xmath2 is high , agents self - organize in a large cluster with few freely moving agents at the boundary . for higher values of @xmath0 , the freely moving phase should exist even for larger @xmath2 . hence , it seems that the role of @xmath2 is to pile up the agents into one large cluster while @xmath0 tends to dispatch them in all directions . for high densities and low @xmath0 , agents pile up into one large cluster even if @xmath2 is vanished ( fig . 5c ) . in the other side , this agglomeration splits up into several clusters when @xmath0 becomes large ( fig . 5d ) . the cluster size distributions of the model are given in figures 6(a - b ) . at low density and for vanished value of @xmath0 , only small clusters are present in the lattice whenever @xmath2 is low . this is one characteristic of the freely moving phase . from results depicted in figure 6a , we observe the bimodal nature of the cluster size distribution as @xmath2 increases . large clusters appear in the lattice but there are by far many more small - sized clusters than larger ones . furthermore , with increasing @xmath2 , the probability of small clusters diminished while that of large cluster increases . another important result is the discontinuity observed from the probability distribution when @xmath2 becomes very large . as it was shown from figure 5b , almost all agents are congested in one large cluster with the exception of a few agents which are located at the boundary and moving towards their destinations . from figure 6a ( @xmath25 and @xmath26 ) , one can see a phase transition from the freely moving phase to the jamming phase , occurring at @xmath27 . indeed , when @xmath28 , the cluster size distribution is a continuous function ; but it becomes discontinuous when @xmath29 . this value of @xmath21 agree with that found in the phase diagram ( fig . in the other hand , when @xmath0 is large enough , we see that large clusters can not exist even for large @xmath2 . it is important to note also that the increase of @xmath0 increases the probability of small - sized clusters ( see figure 6b , higher part ) . at high densities , it is not surprising that large clusters may be usually present in the lattice . however , their sizes depend greatly to the parameter @xmath0 . for example , the most probable cluster size ( of large clusters ) is shifted towards the low size region ( fig . 6b , lower part ) . in contrast to @xmath0 , the effect of @xmath2 on the cluster size distribution is negligible ( result not shown ) . if the density is high , only a small value of @xmath2 may provoke a strong congestion of agents . the second quantity we look at is the travel time , i.e. the time an agent needs to travel from its origin to its destination . the probability distribution of the travel time presents a maximum which is considered as the most probable time , at which an agent finished its travel . at low density and for low @xmath0 , the distribution is sharply peaked around its maximum , whenever @xmath2 is zero ( fig . if @xmath0 increases , one finds evidently a broad distribution of travel time , because agents are moving for quite long times before reaching their destinations . the higher is @xmath0 , the higher is the travel time . as regards the variation of @xmath2 , figure 7b illustrates some graphs of the travel time distributions for low densities and when we set @xmath26 . the interesting observed phenomena is the existence of a double asymptotic behavior . so , when @xmath2 is not large enough , we see that infinite travel time can not exist . in contrast , for large @xmath2 , some agent may take an infinite time to reach its destination . in this case , the agents situated in the interior of the large cluster do not move and rest inside for an indefinite time . when @xmath0 is large enough and the density is low , the travel time distribution changes slightly if @xmath2 is changed ( fig . furthermore , we see that infinite travel time does not occur even for very large @xmath2 . this shows again that the state is the freely moving one at low density and for large @xmath0 . for higher densities , the short travel times still remain , showing the presence of some agents situated at the boundary of a large cluster but the asymptotic behavior is rather increasingly wide ; reflecting the dynamics of agents inside the large clusters ( see figure 7a , lower part ) . indeed , in the presence of large clusters one has to distinguish between inner and outer regions of the cluster . inside , one finds evidently a broad distribution of travel times , because agents are blocked for quite long times . in the outer region of a cluster , however , one finds shorter travel times . furthermore , we find that infinite travel time exist even for large @xmath0 , because the capacity of the freely moving is reduced when there was a big crowd of agents ( congestion ) . in summary , we have tried to identify the behavioral aspects of agents travelling from origins to destinations . the microscopic ca model presented is capable of capturing the self - organization and complex dynamics of agents . the model contains two parameters ( @xmath2,@xmath0 ) and displays two states ; namely the freely moving and the jamming state . the agents speed @xmath15 depends strongly to the parameters ( @xmath2,@xmath0 ) . for low densities , phase transitions occur as the friction parameter @xmath2 exceeds a critical value @xmath21 , which depends on both the density @xmath20 and the noise @xmath0 . in the other hand , it was found that the effect of @xmath2 is to gather different agents into a large cluster . this leads to jamming even at low density . however , the effect of @xmath0 is to disperse agents through the lattice . thus , more mobility and fluidity will affect the whole system . when distinguished for different density ranges , cluster size and travel time distributions have interesting properties . indeed , if @xmath20 and @xmath0 are low , a transition from the freely moving to the jamming states can occur at a critical value @xmath21 . thus , when @xmath28 agents self - organized in small clusters and only short travel times can be taken by agents . however , in the other side ( @xmath29 ) , agents self - organize in one large cluster with very small number of moving agents at the boundary . this is the jamming state where the travel time can be either short and long . so , short travel times concern agents at the boundary of the large cluster while the long times concern those in the inner of the cluster . at high densities , jamming occurs for all values of ( @xmath2,@xmath0 ) . this is due to the reduction of the capacity of a freely moving when there was a big crowd of agents in the lattice . as a result , the speed show a drastic decrease with the density . the cluster size distribution becomes a bimodal distribution which represents a coexistence of large clusters and small ones . yet , the travel time distribution is much broad where infinite travel time exists for all values of the system parameters ( @xmath2,@xmath0 ) . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ * fig.1*. illustration of agent movements in a square lattice with periodic boundary conditions . circles with arrows represent agents while those without arrows represent their destination sites . each arrow indicates the selected site that agent will choose ( here , we set @xmath26 ) . the conflict situation is occurred for the `` white '' and the `` gray '' agents since they select the same site . * fig.2*. diagrams of agents speed versus density for different values of lattice size @xmath8 . * fig.3*. diagrams of agents speed versus @xmath2 for different values of @xmath20 and @xmath0 , ( @xmath30 ) . * fig.4*. phase diagrams of the system for several fixed values of the density : squares , open circles , triangles and solid circles represent @xmath31 , @xmath32 , @xmath33 and @xmath34 respectively , ( @xmath30 ) . * fig.5*. self - organization patterns of agents . black squares represent agents . a ) @xmath35 , @xmath36 and @xmath25 , b ) @xmath37 , @xmath36 and @xmath25 , c ) @xmath38 , @xmath39 and @xmath40 , d ) @xmath38 , @xmath41 and @xmath40 . * fig.6*. cluster size distributions for several values of the system parameters , ( @xmath30 ) . * fig.7*. travel time distributions for several values of the system parameters , ( @xmath30 ) . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

we develop a two - dimensional cellular automaton ( ca ) as a simple model for agents moving from origins to destinations . each agent moves towards an empty neighbor site corresponding to the minimal distance to its destination . the stochasticity or noise ( @xmath0 ) is introduced in the model dynamics , through the uncertainty in estimating the distance from the destination . the friction parameter @xmath1 is also introduced to control the probability that the movement of all agents involved to the same site ( conflict ) is denied at one time step . this model displays two states ; namely the freely moving and the jamming state . if @xmath2 is large and @xmath0 is low , the system is in the jamming state even if the density is low . however , if @xmath2 is large and @xmath0 is high , a freely moving state takes place whenever the density is low . the cluster size and the travel time distributions in the two states are studied in detail . we find that only very small clusters are present in the freely moving state while the jamming state displays a bimodal distribution . at low densities , agents can take a very long time to reach their destinations if @xmath2 is large and @xmath0 is low ( jamming state ) ; but long travel times are suppressed if @xmath0 becomes large ( freely moving state ) . pacs numbers : 45.70.vn , 02.50.ey , 05.40.-a _ keywords : _ traffic ; freely moving ; jamming ; clustering ; travel times .

spintronics , which aims at the manipulation of the electron s spin degree of freedom in electronic devices , has become an emerging field of condensed matter physics for its potential application in information industry.ga,sdr,ball though originally many spintronic concepts involve ferromagnetic metals since spins in this kind of system behave collectively and hence are easier to be controlled,@xcite spintronics in semiconductors is more interesting because dope and heterojunction formation can be used to obtain some specific devices . it is anticipated that combining the advantages of semiconductors with the concepts of spintronics will yield fascinating new electronic devices and open the way to a new field of physics , i.e. , semiconductor spintronics . however , at present many great challenges still remain in this exciting quest . among them , an issue that is fundamentally important in semiconductor spintronics and has not been resolved is how to achieve efficient injections of spins into non - magnetic semiconductors at room temperatureham99,schmd , ohno , fdl , mat03 . usage of ferromagnetic metals as sources of spin - injection is not practical because most of the spin - polarizations will be lost at the interface between metal and semiconductor due to the large conductivity mismatch@xcite . another possible approach is to use ferromagnetic semiconductors ( such as ga@xmath0mn@xmath1as ) instead of ferromagnetic metals as sources of spin - injection . in this approach , the problem of conductivity mismatch does not exist and hence efficient injections of spins into non - magnetic semiconductors can truly be achieved @xcite . but for practical use at room temperature , the curie temperatures of ferromagnetic semiconductors are still too low . thus , from both the experimental and theoretical points of view , more great efforts are still needed in order to achieve efficient injections of spins in non - magnetic semiconductors at room temperature . recently , a surprising effect was predicted theoretically that an electric field may cause a quantum spin hall current in the direction perpendicular to the electric field in conventional hole - doped semiconductors ( such as si , ge , and gaas ) @xcite or in two dimensional electron gases ( 2degs ) with rashba spin - orbit coupling.@xcite this intrinsic @xmath2 hall effect might offer a new approach for achieving efficient injections of spins in non - magnetic semiconductors and reveal a new avenue in the spintronics research . in this paper , we study the influences of spin accumulation on the intrinsic spin hall effect in two dimensional electron gases with rashba spin - orbit coupling . from the standpoint of spintronic applications , it is important to understand whether the spin hall currents predicted in refs.[14 - 15 ] are @xmath3 spin currents , i.e. , whether they can be employed for transporting spins . an important feature of transport spin currents is that they will induce nonequilibrium spin accumulation at some specific locations , for example , at the boundaries of a sample or at the interfaces between two different materials@xcite . on the other hand , if spin accumulation was caused in a sample due to the flow of a spin current , the spin current will also be changed significantly by the spin accumulation.@xcite so in a strict theoretically treatment of the intrinsic spin hall effect , the interplay between the spin hall current and the spin accumulation must be taken into account . a detailed theoretical investigation of the influences of spin accumulation on the intrinsic spin hall effect in hole - doped semiconductors was presented in ref.[16 ] . in the present paper , we will use a similar method as was applied in ref.[16 ] to investigate the influences of spin accumulation on the intrinsic spin hall effect in two dimensional electron gases with rashba spin - orbit coupling . we will show that in contrast with what was found in refs.[15 , 17 - 18 ] , in the presence of spin accumulation , the spin hall conductivity in the intrinsic spin hall effect in a rashba two dimensional electron gas @xmath4 @xmath5 have a universal value , and in order to calculate correctly the spin hall current and the spin hall conductivity in a real sample with boundaries , the influences of spin accumulation need to be taken into account . the paper will be organized as follows : in sec.ii , we will first present a brief introduction to the intrinsic spin hall effect in a rashba two dimensional electron gas in the absence of spin accumulation and impurity scattering . in sec.iii , the influences of spin accumulation and impurity scattering will be taken into account . in sec.iv , by use of the formulas derived in sec.iii , the influences of spin accumulation on the intrinsic spin hall effect in a narrow strip of a rashba two dimensional electron gas will be discussed in detail . in this paper , we will use a slightly different method from what was applied in refs.[15,17 - 18 ] to discuss the intrinsic spin hall effect in two dimensional electron gases with rashba spin - orbit coupling . the merit of this method is that the influences of spin accumulation can be easily included . for clarity , in this section we first present a brief introduction to the intrinsic spin hall effect in the absence of spin accumulation and impurity scattering . we will show that our method will yield the same results as was obtained in refs.[15,17 - 18 ] if spin accumulation and impurity scattering are neglected . in the momentum representation , the single - particle hamiltonian for a two dimensional electron gas with rashba spin - orbit coupling reads@xcite , @xmath6 where @xmath7 is the unit vector along the normal of the two - dimensional plane , @xmath8 is the momentum of an electron , @xmath9 the pauli matrices , and @xmath10 the rashba spin - orbit coupling constant . the hamiltonian ( 1 ) can be diagonalized exactly . the eigenenergies are given by @xmath11 and the corresponding spinor eigenstates are defined by @xmath12 the expectation value of the spin of an electron which is in the spinor eigenstate @xmath13 will be given by @xmath14 where @xmath15 and @xmath16 are the unit vectors along the @xmath17 and @xmath18 axes , respectively , and @xmath19 and @xmath20 are the @xmath17 and @xmath18 components of the spin , which are given by @xmath21 eqs.(4 - 6 ) show that the eigenstates of the hamiltonian ( 1 ) are spin - polarized in the in - plane directions , and the spin - polarization directions depend on the momentum @xmath22 . when an external electric field is applied in the @xmath17 direction , the total hamiltonian of the system will be given by @xmath23 , where @xmath24 is the external electric field and @xmath25 the charge of the electron . the equation of motion for the electron s position and spin degrees of freedom under the action of the external electric field can be obtained directly from the heisenberg equation , and the results read @xmath26where @xmath27 is an effective magnetic field felt by an electron with momentum @xmath22 due to the rashba spin - orbit coupling . the time variation of the spin of an electron which is initially in the spinor eigenstate @xmath28 ( i.e. , @xmath29 ) can be got by solving eqs.(7 - 8 ) simultaneously . in this paper we will consider only the linear response of the transport property to the electric field . in the linear response regime , eqs.(7 - 8 ) can be integrated analytically by use of the same method of ref.[15 ] , and one can find that under the action of the external electric field , the spin of an electron with momentum @xmath22 and initially in the spinor eigenstate @xmath30 will become @xmath31where @xmath32 is the @xmath33th component of the spin . eqs.(9 - 11 ) show that an applied electric field in the @xmath17 direction will cause the spin to tilt in the perpendicular direction by an amount proportional to @xmath34 . due to this fact , the application of an external electric field in the @xmath17 direction will induce a spin hall current in the @xmath35 direction with spin parallel to the @xmath36 direction . the spin hall current can be calculated by the following formula @xmath37where @xmath38 is the probability distribution function of conduction electrons . if spin accumulation and electron - impurity scattering can be neglected , @xmath38 can be given simply by the fermi - dirac equilibrium distribution function , i.e. , @xmath39 + 1\}$ ] , where @xmath40 and @xmath41 is the fermi energy . then one can find that in the usual case where both spin - orbit split bands are occupied , the spin hall current @xmath42 and the spin hall conductivity @xmath43 will be given by@xcite @xmath44eq.(13 ) is the central result of ref.[15 ] , which was also obtained by several other groups with different theoretical approaches.@xcite eq.(13 ) shows that as long as both spin - orbit split bands are occupied , the spin hall conductivity will have a @xmath45 value , independent of both the rashba spin - orbit coupling strength and of the density of conduction electrons . though eq.(13 ) was obtained in the clean limit , recent numerical simulation shows that it still holds in the presence of weak disorder , providing that the sample size exceeds the localization length.@xcite it is also important to note that unlike the similar effect conceived by hirsch@xcite , which is caused by spin - orbit dependent anisotropic scattering from impurities and will vanish in the weak scattering limit , hirsch , zhang , hu the spin hall effect described by eq.(13 ) has a quantum nature and is purely intrinsic , i.e. , it does not rely on any anisotropic scattering from impurities . of course , it should be pointed out that though the mechanism of the intrinsic spin hall effect described above does not involve impurity scattering , it does not mean that impurity scattering have no significant influences on the effect . the reason is that in a real sample , due to the existence of boundaries , nonequilibrium spin accumulation will be caused inevitably near the edges of the sample when the spin hall current circulates in it , and in the presence of nonequilibrium spin accumulation , spin diffusion will be induced by electron - impurity scattering and , hence , the spin hall current may also be changed significantly from what was given by eq.(13 ) . thus in order to calculate correctly the spin hall current and the spin hall conductivity in a real sample with boundaries , the influences of spin accumulation and electron - impurity scattering need to be considered . in the presence of spin accumulation and electron - impurity scattering , the distribution function of conduction electrons can no longer be given simply by the fermi - dirac equilibrium distribution function but should be derived strictly by solving the boltzmann transport equation . in a steady ( but nonequilibrium ) state , the boltzmann equation reads @xmath46 , \label{eq : be}\end{aligned}\ ] ] where @xmath47 is the velocity of conduction electrons , @xmath48is the external electric field applied in the @xmath17 direction , and @xmath49 is the distribution function . the collision term @xmath50 describes the changes of the distribution function due to the intra - band ( @xmath51 ) and/or inter - band ( @xmath52 ) electron - impurity scattering , which is given by @xmath53 , \label{eq : coll2}\end{aligned}\ ] ] where @xmath54 is the rates of an electron to be scattered from the state @xmath55 into the state @xmath56 by impurity scattering . the boltzmann equation ( 14 ) can be solved by the relaxation time approximation method . within the relaxation time approximation and in the linear response regime , the system can be considered only slightly deviated from the equilibrium state , thus the total distribution @xmath57 can be expressed as the sum of the equilibrium distribution function @xmath58 and the non - equilibrium ones as the following @xmath59here the second term denotes the change of the distribution function due to the occurrence of nonequilibrium spin accumulation in the sample , with @xmath60 ( @xmath61 ) denoting the band- and position - dependent shifts of the fermi level in the nonequilibrium state , which characterize the imbalance of the filling of conduction electrons in the two spin - orbit split bands in the presence of nonequilibrium spin accumulation . the third term in eq.(16 ) denotes the changes of the distribution function due to the movement of conduction electrons under the action of an effective electric field @xmath62 , with @xmath63 denoting the total relaxation time of conduction electrons with momentum @xmath22 , which is determined by the electron - impurity scattering . because the occurrence of nonequilibrium spin accumulation will cause spin diffusion in the sample , the effective electric field @xmath62 should be given by @xmath64 , i.e. , in addition to the external electric field @xmath65 , conduction electrons will also feel an effective field given by the gradients of the band- and position - dependent shifts of the fermi level.mr,johnson,ta substitute eq.([eq : f ] ) into eqs.(14 - 15 ) , the left - hand side of the boltzmann equation will become @xmath66\},\end{aligned}\]]and the right - hand side of the boltzmann equation become @xmath67[\mathbf{e}^{\lambda } ( \mathbf{r}% ) \cdot \mathbf{v}_{\lambda } ( \mathbf{k } ) ] \notag \\ & -\frac{\mu ^{\lambda } ( \mathbf{r})-\mu ^{-\lambda } ( \mathbf{r})}{\tau _ { \lambda } ^{\uparrow \downarrow } ( \mathbf{k})}\},\end{aligned}\]]where @xmath68 and @xmath69 are the intra - band and inter - band transition relaxation times , respectively , which are defined by @xmath70^{-1 } \\ & \tau _ { \lambda } ^{\uparrow \downarrow } ( \mathbf{k})=[\int \frac{% d^{2}k^{\prime } } { ( 2\pi ) ^{2}}\omega _ { \lambda , -\lambda } ( \mathbf{k},% \mathbf{k^{\prime } } ) \delta ( \epsilon _ { \lambda } ( \mathbf{k})-\epsilon _ { -\lambda } ( \mathbf{k^{\prime } } ) ) ] ^{-1}.\end{aligned}\]]by integrating both the left - hand side and the right - hand side of the boltzmann equation , one can find that the total relaxation time @xmath71of conduction electrons should be given by @xmath72^{-1},\]]and the band- and position - dependent shifts of the fermi level satisfy the following equation , @xmath73where @xmath74^{1/2}$ ] , with @xmath75 denoting the band - dependent fermi velocity and @xmath76 the inter - band - transition relaxation time and @xmath77 the total relaxation time of conduction electrons at the fermi level , respectively . ( for simplicity , we assume that @xmath77 and @xmath76 are band - independent . ) . from eq.(22 ) , one can see that the relative shifts of the fermi level in the two spin - orbit split bands , given by @xmath78 , satisfy the following diffusion equation , @xmath79=\frac{\mu ^{+}(\mathbf{r})-\mu ^{-}(\mathbf{r})}{d^{2}},\]]where @xmath80 is the spin - diffusion length , defined by @xmath81^{-1/2}.\]]in addition to eqs.(22 - 23 ) , the band - dependent shifts of the fermi level should also satisfy the charge neutrality condition , which requires that the net changes of the charge density due to the band - dependent shifts of the fermi level , given by @xmath82 $ ] , should be zero . this requirement arises from the fact that according to the symmetry of the hamiltonian ( 1 ) , in the direction perpendicular to the external electric field , no charge hall current will be generated , so the occurrence of spin accumulation due to the flow of the spin hall current does not result in charge accumulation . due to this requirement , one can show that in addition to eqs.(22 - 23 ) , the band - dependent shifts of the fermi level should also satisfy the following equation , @xmath83where @xmath84 is the band - dependent wave number at the fermi level . after the band - dependent shifts of the fermi level are determined , the spin hall current can be obtained by inserting eq.(11 ) and eq.(16 ) into eq.(12 ) , then one can find that in the usual case where both spin - orbit split bands are occupied@xcite , the spin hall current and the spin hall conductivity will be given by @xmath85}}{16\pi \alpha [ ( m\alpha /\hbar ^2)^2 + 2m\epsilon _ f/\hbar ^2]^{1/2}}\mathbf{.}\end{aligned}\ ] ] eqs.(26 - 27 ) show that the spin accumulation may have some significant influences on the intrinsic spin hall effect in a rashba two dimensional electron gas . firstly , in the presence of spin accumulation , the spin hall conductivity will be a @xmath86 quantity and @xmath87 @xmath5 have a universal value , i.e. , it will depend on the rashba spin - orbit coupling constant and on the density of conduction electrons . this is very different from what was shown in eq.(13 ) . secondly , in the presence of spin accumulation , the spin hall current may be decreased substantially from the corresponding value obtained in the absence of spin accumulation , and the decrease will be determined by @xmath88 , i.e. , proportional to the relative shifts of the fermi level in the two spin - orbit split bands . eqs.(23,25 ) and ( 2627 ) constitute a set of self - consistent equations , from which both the spin hall current and the spin accumulation can be obtained . in this section , we apply these formulas to discuss the intrinsic spin hall in a narrow strip of a two dimensional electron gas with rashba spin - orbit coupling . narrow strips are the usual geometry applied in the experimental measurement of the hall effect , including the spin hall effect.@xcite in the following we will assume that the longitudinal direction of the strip is along the @xmath17 axis and the transverse direction along the @xmath18 axis and the normal of the 2d plane along the @xmath36 axis , respectively , and an external electric field @xmath89 is applied in the longitudinal direction of the strip . according to eqs.(26)-(27 ) , in order to calculate the spin hall current @xmath90 caused by the longitudinal external electric field @xmath91 , one must first find out the band - dependent shifts @xmath92 and @xmath93 of the fermi level . for simplicity , we assume that the length @xmath94 of the strip is much larger than its width @xmath95 so that spin diffusion in the longitudinal direction of the strip can be neglected . in such case , only transverse spin accumulation need to be considered , and @xmath96 , @xmath97 , and @xmath98 will all depend only on the @xmath18 coordinates . from eq.(23 ) , @xmath99 can be expressed as @xmath100where @xmath101 and @xmath102 are two constant coefficients that need to be determined by appropriate boundary conditions . in this paper , we will consider the transverse - open - circuit boundary condition . in the transverse - open - circuit boundary condition , the spin hall current at the two boundaries of the sample , which are assumed to be located at @xmath103 , should be zero , i.e. , @xmath104substituting eq.([eq : s1 ] ) into eqs.(26 - 27 ) and by use of the above boundary condition , the coefficients @xmath101 and @xmath102 can be determined . then the band- and position - dependent shifts of the fermi level in the strip can be obtained , and we get @xmath105 , \\ & \mu ^{-}(y)=\frac{m_{0}\cosh ( y / d)}{2\cosh ( w/2d)}[\frac{d^{2}}{d_{0}^{2}}% -1],\end{aligned}\]]where @xmath106 and @xmath107 are defined by @xmath108^{-1/2}.\end{aligned}\]]here @xmath109 ( @xmath61 ) has been defined in eq.(22 ) . in obtaining eqs.(30 - 31 ) , the charge neutrality condition ( 25 ) was also used . after @xmath110 is determined , according to eqs.(26 - 27 ) , the spin hall current and the spin hall conductivity will also be obtained , and the results read @xmath111.\end{aligned}\]]eqs.(34 - 35 ) show that , due to the influences of spin accumulation , the spatial distribution of the spin hall current in a sample will be highly inhomogeneous and the spin hall conductivity is sensitively position - dependent . the spin hall current and the spin hall conductivity and their spatial distributions will also have sensitive dependences on the spin diffusion length @xmath80 and the sample width @xmath95 . this was shown in fig.1 , where we have plotted the transverse spatial distributions of the spin hall currents in three distinct cases with different ratios of @xmath112 . from fig.1 , one can see that if @xmath113 , the spin hall current will be negligibly small in the sample , i.e. , @xmath114 everywhere . on the other hand , if @xmath115 , the spin hall conductivity will be approximately a constant at @xmath116 , i.e. , @xmath117 @xmath118 at @xmath116 , which is independent of both the rashba spin - orbit coupling strength and of the density of conduction electrons . but @xmath119 will decrease to zero as @xmath120 . the spin accumulation caused by the longitudinal electric field @xmath121 can be calculated through the following formula @xmath122 where @xmath123 has been given in eqs.(9 - 11 ) . by inserting eq.(16 ) and eqs.(9 - 11 ) into eq.(36 ) and with the help of eqs.(30 - 31 ) , one can find that both the @xmath18 component of @xmath124 ( the in - plane spin accumulation ) and the @xmath36 component of @xmath125 ( the perpendicular spin accumulation ) are non - zero , @xmath126 eqs.(37 - 38 ) show that both the in - plane and the perpendicular spin accumulation are proportional to the longitudinal electric field @xmath121 , but there are some significant differences between them . the in - plane spin accumulation is homogeneously distributed in the sample and independent of both the spin diffusion length @xmath80 and of the sample width @xmath95 . however , the spatial distribution of the perpendicular spin accumulation is highly inhomogeneous and its magnitude depends sensitively on the spin diffusion length @xmath80 and on the sample width @xmath95 . these differences arise from the fact that the in - plane and the perpendicular spin accumulation are caused by very different mechanism . in fact , it was known long time ago that in a two dimensional electron gas with rashba spin - orbit coupling , an applied in - plane electric field will induce a homogeneous in - plane spin accumulation polarized in the direction perpendicular to the electric field@xcite , but the in - plane spin accumulation has nothing to do with the intrinsic spin hall effect . from the theoretical viewpoints , the in - plane spin accumulation is caused by the combined action of the spin - orbit coupling , absence of inversion symmetry , and the time - reversal symmetry - breaking in the electric field@xcite . since the in - plane spin accumulation has been investigated in detail in previous literatures and it has no relation with the intrinsic spin hall effect , we will not discuss it again in the present paper . unlike the in - plane spin accumulation , the perpendicular spin accumulation given by eq.(38 ) is caused by the intrinsic spin hall effect , so its spatial distribution is highly inhomogeneous and its magnitude depends sensitively on the spin diffusion length @xmath80 and on the sample width @xmath95 . this was illustrated clearly in fig.2 , where we have plotted the transverse spatial distributions of the perpendicular spin accumulation in three distinct cases with different ratios of @xmath112 . from fig.2 and eq.(38 ) , one can see that the perpendicular spin accumulation is maximum at the edges of the sample , and the perpendicular spin accumulation at the edges of the sample will increase with the increase of the width of the sample . when the width @xmath95 of the sample is much larger than the spin diffusion length @xmath80 , the perpendicular spin accumulation at the edges of the sample will approach a maximum value of @xmath127 , which is independent of the sample width @xmath95 . this will be a merit for the experimental measurement of the effect . in order to get a quantitative estimation of the perpendicular spin accumulation , let us consider some actual experimental parameters . in current 2deg high quality samplesjdq , others , jth , the typical carrier concentrations range from @xmath128 , the strength of the rashba spin - orbit coupling is on the order of @xmath129 , the effective mass of conduction electrons is about @xmath130 , the relaxation time is typically @xmath131ps,@xmath132the spin diffusion length is about @xmath133 m , and the fermi energy @xmath134 is about @xmath135 if one consider a sample with the width @xmath136 m ( much larger than the spin diffusion length ) and the external field @xmath137 , then from eq.(38 ) one can estimate that the perpendicular spin accumulation at the edges of the sample can be as larger as @xmath138 . this magnitude should be large enough to be detected experimentally . . ( the parameters used are : the sample width @xmath143 @xmath144 m ; the spin diffusion length @xmath140 m ( the solid line ) , @xmath141 m ( the dashed line ) , and @xmath142 m ( the dotted line ) ; the external field @xmath145he rashba spin - orbit coupling constant @xmath146the effective mass @xmath147 @xmath130 ; the relaxation time is @xmath131ps ; and the fermi energy @xmath148 @xmath149),scaledwidth=35.0% ] in conclusion , in this paper we have investigated the influences of spin accumulation on the intrinsic spin hall effect in two dimensional electron gases with rashba spin - orbit coupling . we have presented a detailed theoretical analysis on the interplay between the spin hall current and spin accumulation in the intrinsic spin hall effect in a rashba two dimensional electron gas . we have shown that in the presence of spin accumulation , the spin hall conductivity will not have a universal value . the spin hall current and spin accumulation in narrow strips of two dimensional electron gases with rashba spin - orbit coupling was calculated explicitly . the results show that in order to calculate correctly the spin hall current and the spin hall conductivity in a real sample with boundaries , the influences of spin accumulation need to be taken into account . recently , e. i. rashba pointed out that the hamiltonian ( 1 ) implies that there exist nonvanishing dissipationless spin currents even in the thermodynamic equilibrium state ( i.e. , in the absence of the external electric field ) .@xcite these background spin currents are not associated with real spin transports but spurious effects caused by the lacking of the time - reversal symmetry implied in the hamiltonian ( 1 ) . due to this fact , a procedure for eliminating the spurious effects of these background spin currents should be devised in calculating transport spin currents if the background currents contribute to the calculation . but for the intrinsic spin hall effect discussed in the present paper , the background spin currents do not contribute to the calculation of the spin hall current due to the following reasons . first , the spin hall current is polarized in the direction perpendicular to the 2d plane , while the background spin currents are polarized in the 2d plane . second , the spin hall current is a dynamic response of the spins to the external electric field and will vanish in the absence of the electric field , but the background spin currents are independent of the electric field . due to these reasons , the background spin currents do not present in the calculation of the spin hall current and hence do nt need to be considered in the present paper . this work is supported by a grant from the research grant council of hong kong under contract no . hku 7088/01p and a crcg grant from the university of hong kong . ma and tao would acknowledge the support by national natural science foundation of china and 973 project with no . 2002cb613504 . j. schliemann and d. loss , cond - mat/0310108 ; j. p. hu , b. a. bernevig , and c. wu , cond - mat/0310093 ; s. -q . shen , cond - mat/0310368 ; d. culcer , j. sinova , n. a. sinitsyn , t. jungwirth , a. h. macdonald , and q. niu , cond - mat/0309475 ; n. a. sinitsyn , e. m. hankiewicz , w. teizer , and j. sinova , cond - mat/0310315 . similar to eq.(13 ) , eq.(27 ) is valid only if both spin - orbit split bands are occupied . in the presence of spin accumulation , the condition for both spin - orbit split bands are occupied is @xmath151 ( the bottom of the lower band ) and @xmath152 ( the bottom of the upper band ) . according to the relation of carrier density and fermi level in 2des @xmath153 $ ] , we can get that the carrier density should larger than a @xmath154-dependent value @xmath155 . for real materials , the band - dependent shifts @xmath156 and @xmath157 of the fermi level are usually very small , so the occurence of spin accumulation will not change the situation that whether the two spin - orbit split bands are both occupied or not .

in a two dimensional electron gas with rashba spin - orbit coupling , the external electric field may cause a spin hall current in the direction perpendicular to the electric field . this effect was called the intrinsic spin hall effect . in this paper , we investigate the influences of spin accumulation on this intrinsic spin hall effect . we show that due to the existence of boundaries in a real sample , the spin hall current generated by the intrinsic spin hall effect will cause spin accumulation near the edges of the sample , and in the presence of spin accumulation , the spin hall conductivity will not have a universal value . the influences of spin accumulation on the intrinsic spin hall effect in narrow strips of two dimensional electron gases with rashba spin - orbit coupling are investigated in detail .

people with hiv are living decades longer than before due to combination art ; however , complications including cvd < osteoporosis and non aids defining malignancies are higher than in the general population . many of the emerging complications related to chronic hiv infection represent disease processes where vitamin d is known to play an important role . a single point cross sectional case control study was conducted in a tertiary care hospital to determine the prevalence of vitamin d deficiency and its association with carotid intima media thickness ( cimt ) in hiv patients and to study the association of lipid profile with hiv infection . out of the 45 hiv positive cases , vitamin d deficiency was found in 42 cases ( 93.33% ) whereas only 33 out of 45 ( 73.33% ) healthy controls . a positive association was seen between cd4 levels and 25 hydroxy vitamin d. an inverse co - relation between cd4 count and triglycerides and vldl levels while a positive co - relation with total cholesterol , ldl cholesterol and hdl cholesterol levels was seen . people infected with hiv-1 are at an increased risk of cardiovascular disease ( cvd ) . hiv - infected adults have increased levels of proinflammatory cytokines and endothelial activation markers , which have been associated with cvd in the general population . in addition , the carotid intima - media thickness ( cimt ) , a surrogate marker for atherosclerosis , is associated with levels of proinflammatory cytokines and endothelial activation markers . dyslipidemia is an important metabolic change that may occur in individuals with hiv infection which may contribute to cardiovascular disease . the present study was conducted with the aim to determine the prevalence of vitamin d deficiency and its association with carotid intima media thickness in hiv patients and to study the correlation of lipid profile and hiv infection . the study was conducted in a tertiary care hospital in allahabad from july 2011 to july 2012 . forty - five hiv positive cases diagnosed by elisa , who were 18 years and above and 45 healthy age and sex matched controls were studied . thorough clinical and biochemical examination was done for all cases and controls and they were assessed for fasting blood glucose , fasting lipid profile , hiv 1 and 2 , cd4 count , ecg , cimt , 25(oh)vitamin d. out of the 45 hiv + ve cases , vitamin d deficiency ( 25(oh ) d levels < 30 ng / ml ) was found in 42 cases ( 93.33% ) and 33 out of the 45 ( 73.33% ) age and sex matched healthy controls . twenty - three cases ( 51.11% ) and only 7 controls ( 15.5% ) has deranged lipid profile ( p = . cases were grouped into 4 groups according to their cd4 counts : > 500/mm , 201 - 500/mm , 50 - 200/mm , and < 50/mm . an inverse relationship between cd4 count and triglyceride levels ( r value = -0.221 ) and vldl levels ( r value = -0.234 ) was seen while a gradual decline of total cholesterol levels , ldl levels and hdl levels with decreasing cd4 count was observed ( r values = 0.057 , 0.013 and 0.217 respectively ) . out of the 45 cases , none ( 0% ) had cimt<6 mm , 23(51.11% ) had cimt measuring 6 mm , 7 ( 15.55% ) had cimt measuring 7 mm , 15 ( 13.33% ) had cimt measuring 8 mm and none ( 0% ) measuring > 8 mm compared to controls with 1 ( 2.22% ) who had cimt < 6 mm , 16(35.55% ) with cimt measuring 7 mm , 19 ( 42.22% ) had cimt measuring 7 mm , 9 ( 20% ) had cimt measuring 8 mm and none ( 0% ) measuring > 8 mm . by using statistical analysis , no significant difference in the cimt of hiv positive cases and hiv negative controls was present ( p = 1.00 ) . in this study , the prevalence of vitamin d deficiency in hiv positive cases was 93.33% as compared to a prevalence of 66.66% in the healthy population . lipid profile , in the present study was altered with a prevalence of 51.11% in hiv infected population and 15.55% in the healthy population . alteration in the lipid profile occurred even during the early stages of hiv infection and , more so , as the disease progressed . the fasting total cholesterol , hdl and ldl were significantly lower in the hiv positive subjects as compared to the healthy subjects . whereas fasting triglycerides and vldl were significantly higher in hiv positive cases compared to the hiv negative controls . as the disease progresses with drop in cd4 count , there is a progressive decline in hdl , ldl , and total cholesterol levels and a rise in triglycerides and vldl levels of hiv positive subjects . all the 45 hiv positive cases in our study were assessed for cimt by ultrasonography . percentage of cimt > 8 mm , 8 mm , 7 mm , 6 mm and < 6 mm among the hiv positive population was found to be 0% , 33.33% , 15.55% , 51.11% and 0% as compared to 0% , 20% , 42.22% , 35.55% and 2% in the hiv negative population respectively . there was no significant difference in cimt between the hiv positive cases and the hiv negative controls with a p = 1.00 . in previous studies , right and left cimt were significantly higher in hiv positive groups as compared to the hiv negative controls . significant predictors of cimt measurements in uninfected controls were body mass index and homocysteine , but only the duration of art therapy was predictive of cimt in the hiv infected group . out of the 45 cases in this study , 42 had vitamin d deficiency and their mean cimt was 0.65 mm compared to the 33 out of the 45 healthy controls who are vitamin d deficient with mean cimt = 0.68 mm . there was no significant difference between the two groups , which was contrary to findings of previous studies where the relationship between vitamin d insufficiency and increased cimt in hiv positive patients remained significant even after adjustment for traditional risk factors for hardening of the arteries , hiv related factors like viral load and duration of antiretroviral therapy and lipid levels . vitamin d deficiency was significantly higher in hiv patients as compared to age and sex matched healthy controls and hence such patients would benefit from vitamin d supplementation given at initiation of art as it would offer a safe and effective means of augmenting the immune restoration response to treatment . it can also be concluded that lipid profile may be a good index of disease progression in hiv patients .

background : people with hiv are living decades longer than before due to combination art ; however , complications including cvd < osteoporosis and non aids defining malignancies are higher than in the general population . many of the emerging complications related to chronic hiv infection represent disease processes where vitamin d is known to play an important role.objectives:a single point cross sectional case control study was conducted in a tertiary care hospital to determine the prevalence of vitamin d deficiency and its association with carotid intima media thickness ( cimt ) in hiv patients and to study the association of lipid profile with hiv infection . out of the 45 hiv positive cases , vitamin d deficiency was found in 42 cases ( 93.33% ) whereas only 33 out of 45 ( 73.33% ) healthy controls . fifty one point eleven percent of cases had dyslipidemia compared to 15.55% of controls . a positive association was seen between cd4 levels and 25 hydroxy vitamin d. an inverse co - relation between cd4 count and triglycerides and vldl levels while a positive co - relation with total cholesterol , ldl cholesterol and hdl cholesterol levels was seen . no significant difference was seen in cimt in cases and controls .

MIAMI - A 60-year-old Venezuelan neurosurgeon who allegedly claimed that he had explosives in his luggage as he was getting ready to board an Avianca flight to Colombia has agreed to pay $89,172.53 for the "joke" that shut down two concourses at Miami International Airport two months ago. Dr. Manuel Alvarado's attorney, Brian Bieber, said his client was sleep deprived the day of the incident and that he suffered from a momentary lapse of reason. Prosecutors decided against filing formal charges of making a false bomb threat and criminal mischief after Alvarado agreed to pay the nearly $90,000 for the mistake that caused thousands of passengers to be delayed. Officials said $84,000 of the money Alvarado will pay will go to the five airlines that were delayed due to his claim. "I commend the Miami-Dade State Attorney’s Office for evaluating the facts and making the right decision," Bieber said. A majority of the rest of the money will go the the Miami-Dade Police Department, which was responsible for deploying the bomb squad to search the doctor's luggage. "I feel very ashamed and sorry for that stupid thing I said," Alvarado wrote in a confession. "I am very, very sorry." Bieber said in the post-911 era, it isn't uncommon for airlines to request restitution from passengers in certain cases.

– It might be the most expensive failed joke ever: A neurosurgeon has to pay more than $89,000 because he thought it would be funny to tell a ticket agent at Miami International Airport that he had explosives in his bag, reports Local10. Most of the money will go to five airlines that had to delay flights in the chaos that ensued last October, but the Miami-Dade Police Department will get a slice, too. One bright spot for 60-year-old Manuel Alvarado: The Venezuelan will not face formal charges of making a false bomb threat. “I feel very ashamed and sorry for that stupid thing I said,” wrote Alvarado in a confession. “I am very, very sorry.” The Miami Herald has details on the joke: When the ticket agent asked Alvarado whether he had explosives in his luggage, he answered, "C-4." When the agent asked whether that was a gun, Alvarado explained that C-4 was an explosive—a response that led to a massive police response and delays for thousands of passengers, all while the good doctor was trying to explain that he was just kidding.

graphene,@xcite a two - dimensional single layer of carbon atoms packed into a honeycomb lattice , has aroused enormous interest in recent years due to its intriguing properties.@xcite particular efforts have been devoted into the graphene nanoribbons ( gnrs),@xcite quasi one dimension ribbon like structures resulted from the finite termination of the graphene with two different possible edge geometries , namely armchairs and zigzags . since gnrs have a tunable band gap sensitive to the size and geometry , they are good candidates for the possible electronic and spintronic devices , such as the field effect transistor,@xcite the spin filter and spin transistor.@xcite to realize these devices , it is required to manipulate the transport through the gnrs in a controllable manner . among various schemes , to modulate the transport using different shapes of gnrs , e.g. , u - shaped , s - shaped , and t - shaped are of particular interest.@xcite in the t - shaped gnrs , the possible ( quasi-)bound states trapped at the intersection due to the t - shaped confinement@xcite provides another channel to modulate the transport through the fano effect,@xcite which stems from the interference between the path through a discrete state and the path through a continuum when the discrete state embeds in the continuum . the localized states in t - shaped structures composed of the conventional semiconductor quantum wires have long been studied.@xcite it is shown that there is one bound state lying below and one quasi - bound state embedding in the lowest conduction band . the existence of the quasi - bound state results in the asymmetrical dip in the energy dependence of the conductance , which is the character of the fano effect.@xcite since the gnrs have much more complex band structures which strongly depend on the geometry and ribbon size,@xcite the t - shaped structures consists of gnrs are expected to have more complex behaviors . recently , the quasi - bound states are shown to play an important role in the transport through the zigzag gnr in the t - shaped gnr structure consisting of a zigzag gnr connected to an armchair sidearm.@xcite however , in the t - shaped gnr structure consisting of a metallic armchair gnr connected to a zigzag sidearm , which is more interesting for transport since the lowest excitations in the gapless armchair gnrs are massless dirac fermions whose spectrum is linear with the momentum , the existence of the ( quasi)-bound states have not yet been studied . if the ( quasi-)bound states exist , they have to embed in the continuum due to the gapless band structures of both the armchair gnr and the zigzag sidearm . therefore , these states are expected to greatly affect the transport of the dirac fermions through the armchair gnr through the fano effect . in this work , we systematically investigate the quasi - bound states and the resulting fano effect in the t - shaped gnr consisting of a metallic armchair gnr connected to a zigzag sidearm . we list the condition of the existence of such quasi - bound states for a wide range of ribbon size and study the effect of these states on the transport . and a zigzag gnr lead of width @xmath0 . the insets at the top - left and top - right cornors show how the sizes along the armchair and zigzag edges are defined . in this scheme , @xmath1 and @xmath2 . , width=294 ] the t - shaped structure we study is composed of an armchair gnr of width @xmath3 connected to a sidearm of width @xmath0 , as schematically illustrated in the fig . [ figxww1 ] . we divide the system into four parts , the left , right and top leads as well as the central junction . the hamiltonian of the system consists of the hamiltonians @xmath4 for each part and their couplings @xmath5 . using the tight - binding model under the nearest - neighbor approximation , the hamiltonian are written as @xmath6 here , @xmath7 is the hopping parameter@xcite and @xmath8 , set to 0 , is the on - site energy . @xmath9 denotes that the sum is restricted to the nearest neighbors . within the landauer - bttiker framework,@xcite the transmission amplitude of the electrons with energy @xmath10 between leads @xmath11 and @xmath12 is @xmath13,\label{landauer}\ ] ] where @xmath14 and @xmath15 are the retarded / advanced green s function and the tunneling rate matrix , respectively . the retarded green s function is given by @xmath16^{-1},\label{green}\ ] ] in which , @xmath17 represents the retarded self - energy matrix . it can be expressed as @xmath18 , with @xmath19 and @xmath20 being the retarded surface green s function of lead @xmath11 and the hopping matrix between the lead @xmath11 and the central junction @xmath21.@xcite similarly , one can write down the advanced green s function . the surface green s function can be calculated through an iterative scheme.@xcite the tunneling rate matrix can be obtained from the self - energy , @xmath22\ ; .\ ] ] the quasi - bound state is studied by diagonalizing the hamiltonian @xmath23 numerically . the quasi - bound states can also be shown through the local density of state ( ldos ) , which can be obtained from the green s function . and @xmath24 . @xmath25 is the carbon - carbon bond distance.,width=321 ] we first study the existence conditions of the quasi - bound states located at the intersection of the t - shaped gnrs . the states we are interested in are the ones whose eigen - energies are lower than the edges of the second sub - band of the leads . they are picked out according to the following rules : ( 1 ) the probability density of the state concentrates at the intersection ; ( 2 ) the state is insensitive to the boundaries , that is , the state undergoes small changes when the lengths of the central junction ( @xmath26 or @xmath27 in fig . [ figxww1 ] ) change . we find that the quasi - bound states exist in the structures only when the width ratio between the armchair gnr and sidearm is in certain regime . the conditions under which the quasi - bound states exist are listed in table [ table1 ] for a wide range of the armchair gnr width @xmath3 , together with their eigenenergies . to show that these states are indeed trapped at the central junction , we plot the probability density for the quasi - bound state in fig . [ figxww2 ] for a typical t - shaped gnr structure with @xmath28 , @xmath24 . one sees from the figure that for this state the electron indeed concentrates at the intersection . moreover , the wave - function decays exponentially along the sidearm , but its amplitude along the two armchair gnrs is finite although small which implies that the state is a quasi - bound state . the localized components of the quasi - bound states , whose energy is below the second sub - band edges , mainly come from the second sub - band of the gnrs.@xcite therefore , the probable condition for the quasi - bound state to exist is when the second sub - band edges of both the armchair gnr and the zigzag sidearm are comparable . in our setup the optimal condition for the quasi - bound states which is when @xmath0 is about @xmath29 , as it can be seen from table [ table1 ] . lllll @xmath3&@xmath0&&@xmath3&@xmath0 + + 11 & 5 ( 1079 ) & & 23 & 10 ( 561 ) , 11 ( 527 ) + + 14 & 6 ( 898 ) & & 26 & 11 ( 500 ) , 12 ( 480 ) , 13 ( 457 ) + + 17 & 8 ( 712 ) & & 29 & 12 ( 452 ) , 13 ( 438 ) , 14 ( 418 ) + + 20 & 9 ( 626 ) , 10 ( 578 ) & & 32 & 13 ( 420 ) , 14 ( 406 ) , 15 ( 379 ) , + & & & & 16 ( 366 ) + + and different @xmath0 : @xmath30 ( blue chained curve ) , @xmath31 ( purple long dashed curve ) , @xmath24 ( red solid curve ) , @xmath32 ( green short dashed curve ) ; ( b ) and ( c ) : ldos at the transmission dips of @xmath33 for @xmath24 and @xmath34 , respectively.,title="fig:",width=321 ] and different @xmath0 : @xmath30 ( blue chained curve ) , @xmath31 ( purple long dashed curve ) , @xmath24 ( red solid curve ) , @xmath32 ( green short dashed curve ) ; ( b ) and ( c ) : ldos at the transmission dips of @xmath33 for @xmath24 and @xmath34 , respectively.,title="fig:",width=321 ] we now investigate the transport properties of t - shaped gnr structure . we concentrate on the energy range near the dirac point . in fig . [ figxww3](a ) we plot the transmission amplitudes between the left and right leads @xmath33 ( upper panel ) and between the left lead and the sidearm @xmath35 ( lower panel ) as the functions of the electron energy for t - shaped gnr structure with the same width of the armchair gnr ( @xmath28 ) but different sidearm widths . for @xmath28 , we have shown that the quasi - bound states exist only when @xmath31 and @xmath36 in the above section . the quasi - bound states have strong effect on the transmission between the left and right leads . one finds the a dip close to zero with an asymmetric line shape at @xmath37 mev for @xmath31 and a similar dip at @xmath38 mev for @xmath24 . the position of the dips are close to the corresponding eigen - energies of the quasi - bound states obtained from the diagonalization . the sharp dip near the eigen - energy of the quasi - bound state with an asymmetric line shape is the character of the fano effect . therefore one can see that the fano effect strongly affects in the transmission between left and right leads . the sharp dip disappears when there is no quasi - bound state , as in the case of @xmath30 and @xmath39 . in the energy regime shown in the figure , there are only shallow dips for @xmath30 and @xmath39 at @xmath40 mev and @xmath41 mev , which are the second sub - band edge of the horizontal gnr for @xmath42 and that of the sidearm gnr for @xmath32 , respectively . the shallow dips at the sub - band edges are strongly related to the opening of new conduction channels , which can be clearly seen from the boost in @xmath35 accompanying these dips in @xmath33 as shown in the lower panel of fig . [ figxww3](a ) . from the lower panel , one can also see that the quasi - bound states do not have any impact on the transmission between the left lead and the sidearm @xmath35 , since the quasi - bound states are localized along the sidearm . additionally , the localization of the quasi - bound states is also identified by the local density of state in fig . [ figxww3](b ) and ( c ) . , @xmath24 and different sidearm length : @xmath43 ( purple long dashed curve ) , @xmath44 ( green short dashed curve ) , @xmath45 ( blue chained curve ) . we also plot @xmath33 for the t - shaped gnr structure of same @xmath3 and @xmath0 ( red solid curve ) for comparison . ( b ) and ( c ) are the ldos at @xmath46 mev and @xmath47 mev for t - stub structure with sidearm length @xmath48 , respectively . , title="fig:",width=321 ] , @xmath24 and different sidearm length : @xmath43 ( purple long dashed curve ) , @xmath44 ( green short dashed curve ) , @xmath45 ( blue chained curve ) . we also plot @xmath33 for the t - shaped gnr structure of same @xmath3 and @xmath0 ( red solid curve ) for comparison . ( b ) and ( c ) are the ldos at @xmath46 mev and @xmath47 mev for t - stub structure with sidearm length @xmath48 , respectively . , title="fig:",width=321 ] it should be further noted that the sharp dips caused by the fano effect when the quasi - bound states exist should be distinguished from the ones due to the structure anti - resonance in the t - stub gnrs , i.e. , without the lead connected to the sidearm.@xcite in figure [ figxww4](a ) the transmission amplitudes @xmath33 for different sidearm lengths are plotted as functions of the energy for the t - stub gnr structure with @xmath28 and @xmath24 . one sees that apart from the sharp dip at @xmath49 mev caused by the quasi - bound state trapped at the central junction for all sidearm lengths , there are dips caused by the structure anti - resonance due to the resonance states in the t - stub.@xcite unlike the dip due to the quasi - bound state , the structure anti - resonance dips are sensitive to the sidearm length . to distinguish the quasi - bound state and the anti - resonance states , we also plot the ldos corresponding to the fano dip and a structure anti - resonance dip when @xmath48 in figs . [ figxww4](b ) and [ figxww4](c ) , respectively . it can be clearly seen that the quasi - bound state mainly concentrates at the intersection and while the anti - resonant state spreads over all of the entire sidearm . in summary , we have studied the quasi - bound states and the transport properties in the t - shaped gnr composed of a metallic armchair gnr and a zigzag sidearm . we systematically study the existence of the quasi - bound state in this structure for a wide range of the system size . we find that there are quasi - bound states when the width of the armchair gnr is about twice of sidearm width . the quasi - bound states are trapped at the intersection of the t - shaped junction and are truly localized along the sidearm direction . the quasi - bound states have strong effects on the transport between the two armchair leads but have no effect on the transport between the armchair lead and the sidearm . due to these quasi - bound states , the fano effect manifests through a characteristic dip with an asymmetrical line sharp in the energy dependence of transmission between the armchair leads . we would like to thank m.w.wu for proposing the topic as well as directions during the investigation . this work was supported by the national basic research program of china under grant no . 2012cb922002 and the strategic priority research program of the chinese academy of sciences under grant no .

we study the quasi - bound state and the transport properties in the t - shaped graphene nanoribbon consisting of a metallic armchair - edge ribbon connecting to a zigzag - edge sidearm . we systematically study the condition under which there are quasi - bound states in the system for a wide range of the system size . it is found that when the width of the sidearm is about half of the width of the armchair leads , there is a quasi - bound state trapped at the intersection of the t - shape structure . the quasi - bound states are truly localized in the sidearm but have small continuum components in the armchair leads . the quasi - bound states have strong effect on the transport between the armchair leads through the fano effect , but do not affect the transport between the armchair lead and the sidearm .

SECTION 1. SHORT TITLE. This Act may be cited as the ``Medicare Enhancements for Needed Drugs Act of 2005''. SEC. 2. GAO STUDIES AND REPORTS ON PRICES OF PRESCRIPTION DRUGS. (a) Review and Reports on Retail Prices of Prescription Drugs.-- (1) Initial review.--The Comptroller General of the United States shall conduct a review of the retail cost of prescription drugs in the United States during 2000 through 2003, with an emphasis on the prescription drugs most utilized for individuals age 65 or older. (2) Subsequent review.--After conducting the review under paragraph (1), the Comptroller General shall continuously review the retail cost of such drugs through April 1, 2006, to determine the changes in such costs. (3) Reports.-- (A) Initial review.--Not later than September 1, 2005, the Comptroller General shall submit to Congress a report on the initial review conducted under paragraph (1). (B) Subsequent review.--Not later than July 1, 2006, January 1, 2007, and July 1, 2007, the Comptroller General shall submit to Congress a report on the subsequent review conducted under paragraph (2). (b) Annual GAO Study and Report on Retail and Acquisition Prices of Certain Prescription Drugs.-- (1) Ongoing study.--The Comptroller General of the United States shall conduct an ongoing study that compares the average retail cost in the United States for each of the 20 most utilized prescription drugs for individuals age 65 or older with-- (A) the average price at which private health plans acquire each such drug; (B) the average price at which the Department of Defense under the Defense Health Program acquires each such drug; (C) the average price at which the Department of Veterans Affairs under the laws administered by the Secretary of Veterans Affairs acquires each such drug; and (D) the average negotiated price for each such drug that eligible beneficiaries enrolled in a prescription drug plan under part D of title XVIII of the Social Security Act, as added by section 101 of the Medicare Prescription Drug, Improvement, and Modernization Act of 2003 (Public Law 108-173), that provides only basic prescription drug coverage have access to under such plans. (2) Annual report.--Not later than December 1, 2007, and annually thereafter, the Comptroller General shall submit to Congress a report on the study conducted under paragraph (1), together with such recommendations as the Comptroller General determines appropriate. SEC. 3. INCLUSION OF AVERAGE AGGREGATE BENEFICIARY COSTS AND SAVINGS IN COMPARATIVE INFORMATION FOR BASIC MEDICARE PRESCRIPTION DRUG PLANS. Section 1860D-1(c)(3) of the Social Security Act (42 U.S.C. 1395w- 101(c)(3)) is amended-- (1) in subparagraph (A)-- (A) in the matter preceding clause (i), by striking ``subparagraph (B)'' and inserting ``subparagraphs (B) and (C)''; and (B) by adding at the end the following new clause: ``(vi) Average aggregate beneficiary costs and savings.--With respect to plan years beginning on or after January 1, 2007, the average aggregate costs, including deductibles and other cost-sharing, that a beneficiary will incur for covered part D drugs in the year under the plan compared to the average aggregate costs that an eligible beneficiary with no prescription drug coverage will incur for covered part D drugs in the year.''; and (2) by adding at the end the following new subparagraph: ``(C) Average aggregate beneficiary costs and savings information only for basic prescription drug plans.--The Secretary shall not provide comparative information under subparagraph (A)(vi) with respect to-- ``(i) a prescription drug plan that provides supplemental prescription drug coverage; or ``(ii) a Medicare Advantage plan.''. SEC. 4. NEGOTIATING FAIR PRICES FOR MEDICARE PRESCRIPTION DRUGS. (a) In General.--Section 1860D-11 of the Social Security Act (42 U.S.C. 1395w-111) is amended by striking subsection (i) (relating to noninterference) and by inserting the following: ``(i) Authority To Negotiate Prices With Manufacturers.-- ``(1) In general.--In order to ensure that beneficiaries enrolled under prescription drug plans and MA-PD plans pay the lowest possible price, the Secretary shall have authority similar to that of other Federal entities that purchase prescription drugs in bulk to negotiate contracts with manufacturers of covered part D drugs, consistent with the requirements and in furtherance of the goals of providing quality care and containing costs under this part. ``(2) Mandatory responsibilities.--The Secretary shall be required to-- ``(A) negotiate contracts with manufacturers of covered part D drugs for each fallback prescription drug plan under subsection (g); and ``(B) participate in negotiation of contracts of any covered part D drug upon request of an approved prescription drug plan or MA-PD plan. ``(3) Rule of construction.--Nothing in paragraph (2) shall be construed to limit the authority of the Secretary under paragraph (1) to the mandatory responsibilities under paragraph (2).''. (b) Effective Date.--The amendment made by this section shall take effect as if included in the enactment of section 101 of the Medicare Prescription Drug, Improvement, and Modernization Act of 2003 (Public Law 108-173). SEC. 5. NAIC REVIEW AND REPORT ON CHANGES IN MEDIGAP POLICIES THAT PROVIDE COVERAGE OF PRESCRIPTION DRUGS CONTAINED IN THE MEDICARE PRESCRIPTION DRUG, IMPROVEMENT, AND MODERNIZATION ACT OF 2003. (a) In General.--The Secretary of Health and Human Services shall request the National Association of Insurance Commissioners to conduct a review of the changes to the rules relating to medicare supplemental policies that provide prescription drug coverage contained in subsection (v) of section 1882 of the Social Security Act (42 U.S.C. 1395ss), as added by section 104(a) of the Medicare Prescription Drug, Improvement, and Modernization Act of 2003 (Public Law 108-173). (b) Impact on Medicare Beneficiaries.--The review conducted pursuant to subsection (a) should focus on the impact the changes described in such subsection will have on medicare beneficiaries. (c) Report.--The Secretary shall request the National Association of Insurance Commissioners to submit to Congress, by not later than January 1, 2006, a report on the review conducted pursuant to subsection (a), together with such recommendations as the National Association of Insurance Commissioners determines appropriate.

Medicare Enhancements for Needed Drugs Act of 2005 - Directs the Comptroller General to review and report to Congress on the retail cost of prescription drugs in the United States during 2000 and 2003, and through April 1, 2006, with an emphasis on the prescription drugs most utilized for individuals age 65 or older. Requires the Comptroller General to conduct an ongoing study that compares the average retail cost in the United States for each of the 20 most utilized prescription drugs for individuals age 65 or older with: (1) the average prices at which private health plans, the Department of Defense under the Defense Health Program, and the Department of Veterans Affairs acquire each such drug; and (2) the average negotiated price for each such drug that eligible beneficiaries have access to under a Medicare prescription drug plan providing only basic prescription drug coverage. Amends title XVIII (Medicare) of the Social Security Act (SSA) to include in the comparative plan information for beneficiaries under new Medicare part D (Voluntary Prescription Drug Benefit Program) a comparison of average aggregate prescription drug plan beneficiary costs and savings with such costs for a beneficiary with no prescription drug plan. Repeals the prohibition against interference by the Secretary with the negotiations between drug manufacturers and pharmacies and prescription drug plan sponsors, as well as the requirement of a particular formulary to institute a price structure for the reimbursement of Medicare part D covered drugs. Authorizes the Secretary instead, like other Federal entities that purchase prescription drugs in bulk, to negotiate contracts with manufacturers of covered part D drugs.

the time evolution of the joint probability @xmath80 of finding at time @xmath81 the tp at the site with the configuration of obstacles @xmath45 , is governed by the following master equation @xmath82 \nonumber \\ & + & \frac{1}{\tau}\sum_{\mu=1}^dp_\mu\{[1-\eta(\boldsymbol{r}_{tp})]p(\boldsymbol{r}_{tp}-\boldsymbol{e}_{\mu},\eta ; t ) -[1-\eta(\boldsymbol{r}_{tp}+\boldsymbol{e}_{\mu})]p(\boldsymbol{r}_{tp},\eta ; t)\},\end{aligned}\ ] ] where @xmath83 is the configuration obtained from @xmath45 by exchanging the occupation numbers of sites @xmath84 and @xmath85 . the stationary velocity of the tp is obtained by multiplying both sides of the master equation by @xmath86 , summing over all possible configurations @xmath87 , and taking the limit @xmath88 . this yields the expression @xmath89-p_{-1 } \left[1-k(\boldsymbol{e}_{-1})\right]\right\},\ ] ] where the functions @xmath90 are the stationary values ( in the @xmath91 limit ) of @xmath92 , defined as @xmath93 we define @xmath92 for @xmath94 by @xmath95 . the evolution equations for @xmath96 may be obtained by multiplying the master equation by @xmath97 and summing over all the configurations of @xmath87 . we get the following equation : @xmath98\nabla_\nu\eta(\boldsymbol{r}_{tp}+{\boldsymbol{\lambda } } ) \right\rangle } , \label{}\ ] ] where we introduced the average @xmath99 , and @xmath67 is a differential operator defined by the relation @xmath100 . in order to solve this equation , we use the decoupling approximation proposed in the main text : @xmath46 which is valid for @xmath101 . for convenience , we also introduce the functions @xmath102 , defined by @xmath103 one finally shows that @xmath104 satisfy the following evolution equations @xmath105 with @xmath106 and @xmath107 $ ] . we introduce the auxiliary variable @xmath108 and the generating function @xmath109 where the shorthand notation @xmath110 has been used . @xmath111 are the components of the vector @xmath112 . if @xmath113 then we use @xmath114 . from eqs . ( [ hbulk ] ) and ( [ hboundary ] ) we can show that @xmath115 is the solution of the following partial differential equation @xmath116h(\boldsymbol{\xi};t)+k(\boldsymbol{\xi};t ) , \label{h}\ ] ] with @xmath117 and @xmath118 + \rho(a_1-a_{-1 } ) \left ( \xi_1-\frac{1}{\xi_1}\right).\end{aligned}\ ] ] the stationary solution of eq . ( [ h ] ) is @xmath119}.\ ] ] we rewrite the auxiliary variables as @xmath120 , and introduce the function @xmath121^d } dq_1\dots dq_d \frac{\prod_{j=1}^d { \mathrm{e}^{-in_j q_j}}}{1-\lambda(q_1,\dots , q_d ) } \label{def_fn_inf}\ ] ] with @xmath122 so that @xmath123 becomes @xmath124 note that @xmath66 is the long - time limit of the generating function of a biased random walk on @xmath125-dimensional lattice @xcite . using the definition of @xmath66 from eq . ( [ def_fn_inf ] ) , and taking the inverse fourier transforms , we get @xmath126 using eq . ( [ def_h_k_inf ] ) , @xmath127 finally , using the definition of @xmath128 in eq . ( [ defk ] ) , writing @xmath129 using eq . ( [ generating_h ] ) and identifying the terms from both sides of eq . ( [ system_gf ] ) , one shows that @xmath130 is given by the following system of @xmath18 equations @xmath131 where @xmath132 are taken equal to the coordinates of the base vectors @xmath133 . noticing that @xmath134 for symmetry reasons , this system of @xmath18 equations may be reduced to a system of three equations ( @xmath135 ) @xmath136 . \label{system_text}\ ] ] in the above expressions the matrix @xmath137 , @xmath138 , and the matrix @xmath139 is obtained from the matrix @xmath140 by replacing the column corresponding to the index @xmath13 with the column vector @xmath141 . notice that the functions @xmath66 , defined in ( [ def_fn_inf ] ) can be rewritten as @xmath142 @xmath143 being the components of the base vector @xmath112 and @xmath144 - the modified bessel function of first kind . for the general @xmath145dimensional case the functions @xmath146 satisfy the system ( [ system ] ) . in order to derive an approximated solution in the low density limit , we introduce the variables @xmath64 via the relation @xmath147 when @xmath148 , we use @xmath149 , so that the expression for the tracer velocity becomes @xmath150 in the low density limit @xmath9 the coefficients @xmath61 can be approximated as @xmath151 and , substituting the expression ( [ h_rho ] ) into ( [ system ] ) , one obtains the system satisfied by the variables @xmath64 @xmath152v_{\boldsymbol{e}_\nu}\nabla_{-\nu}\mathcal{f}_{\boldsymbol{n } } -2dx(p_1-p_{-1})(\nabla_1-\nabla_{-1})\mathcal{f}_{\boldsymbol{n } } , \label{lin_system}\ ] ] where @xmath153 . notice that the system ( [ lin_system ] ) obtained in the low density approximation is linear in the variables @xmath64 . let us consider the explicit case @xmath7 , in the limit of the standard lorentz gas , namely when @xmath154 . then the functions @xmath66 simplify to @xmath70 with @xmath71 . introducing the variables @xmath155 , with @xmath156 , through the relation @xmath157 , we obtain the following linear system @xmath158 notice that the expression ( [ f_inf ] ) corresponds to the perturbed time evolution operator ( integrated in time ) introduced in ref . @xcite . in order to explicitly recover the solution reported in @xcite , we notice that , using the expressions for the probabilities @xmath159 , @xmath160 and @xmath161 , the following identities can be obtained @xmath162 finally , expressing the functions @xmath163 and @xmath164 in terms of @xmath165 and @xmath166 , namely @xmath167 one can check that from the system ( [ system_lorentz ] ) the explicit solution reported in @xcite follows . the solution of the system ( [ lin_system ] ) gives the coefficients @xmath168 and @xmath169 appearing in the expression ( [ vel ] ) . these coefficients depend on @xmath170 and on the probabilities @xmath171 , @xmath172 , both explicitly and implicitly through the functions @xmath66 . in order to find the condition for negative differential mobility , we consider the case of large force , such that @xmath173 where @xmath33 is a small quantity . substituting these expressions into the definition of @xmath66 , we can expand to the first order in @xmath33 to get @xmath174 where @xmath175 and @xmath176 . next , substituting eqs . ( [ epsi ] ) and ( [ f_epsi ] ) into the solutions of the system ( [ lin_system ] ) , and retaining only the terms up to the order @xmath33 , we obtain the expression for the coefficients @xmath177 @xmath178 notice that @xmath179 and @xmath180 still have both an explicit and an implicit dependence on @xmath170 , through the functions @xmath181 and @xmath182 . thus , for the tracer velocity ( [ vel ] ) to the order @xmath33 we have @xmath183 \nonumber \\ & = & 1-\rho\left(1+v_1^{(0)}\right ) -\epsilon \left[1-\rho \left(1+v_1^{(0)}-v_1^{(1)}\right)\right].\end{aligned}\ ] ] eventually , writing @xmath184 with @xmath185 \\ v^{(1)}(x ) & = & \frac{1}{\tau } \left[-1+\rho \left(1+v_1^{(0)}(x)-v_1^{(1)}(x)\right)\right ] , \end{aligned}\ ] ] a general criterion for negative differential mobility can be obtained by studying the sign of the term @xmath186 , which yields the condition @xmath187 where @xmath188 . \label{hx}\ ] ] the functions @xmath189 and @xmath190 satisfy the system obtained by expanding ( [ lin_system ] ) to the first order in @xmath33 . in particular , in the case @xmath7 , to the zero order we have @xmath191 where , dropping the dependence on @xmath170 in the functions @xmath66 , @xmath192 @xmath193 and @xmath194 therefore @xmath195 where @xmath196 is obtained from @xmath197 replacing the first column with the vector @xmath198 . analogously , for @xmath199 , we have to solve the system @xmath200 where @xmath201 @xmath202 and @xmath203 with @xmath204 , \\ b_{12}&= & -v_1^{(0 ) } ( \mathcal{f}^{(1)}_{-2,0}-\mathcal{f}^{(1)}_{-1,0})+2 v_{2}^{(0 ) } \mathcal{f}^{(1)}_{-1,0}+v_{-1}^{(0 ) } \mathcal{f}^{(1)}_{-1,0 } -2 v_{2}^{(0 ) } \mathcal{f}^{(1)}_{-1,1}-v_{-1}^{(0 ) } \mathcal{f}^{(1)}_{0,0 } \nonumber \\ & + & 4 x \left[(v_1^{(0)}+1 ) \mathcal{f}^{(0)}_{-2,0}+v_{2}^{(0 ) } \mathcal{f}^{(0)}_{-1,0}-v_{2}^{(0 ) } \mathcal{f}^{(0)}_{-1,1}-\mathcal{f}^{(0)}_{0,0}-\mathcal{f}^{(1)}_{-2,0}-v_1^{(0 ) } ( \mathcal{f}^{(0)}_{-1,0}+\mathcal{f}^{(1)}_{-2,0}-\mathcal{f}^{(1)}_{-1,0})+\mathcal{f}^{(1)}_{0,0}\right ] , \\ b_{13}&=&-v_{2}^{(0 ) } \mathcal{f}^{(1)}_{0,0}-v_1^{(0 ) } ( \mathcal{f}^{(1)}_{-1,1}-\mathcal{f}^{(1)}_{0,1})+2 v_{2}^{(0 ) } \mathcal{f}^{(1)}_{0,1}-v_{2}^{(0 ) } \mathcal{f}^{(1)}_{0,2}+v_{-1}^{(0 ) } \mathcal{f}^{(1)}_{0,2 } \nonumber \\ & -&2 x \big[-2 ( v_1^{(0)}+1 ) \mathcal{f}^{(0)}_{-1,1}+v_{2}^{(0 ) } ( \mathcal{f}^{(0)}_{0,0}-2 \mathcal{f}^{(0)}_{0,1}+\mathcal{f}^{(0)}_{0,2 } ) \nonumber \\ & + & 2 ( \mathcal{f}^{(0)}_{1,1}+\mathcal{f}^{(1)}_{-1,1}+v_1^{(0 ) } ( \mathcal{f}^{(0)}_{0,1}+\mathcal{f}^{(1)}_{-1,1}-\mathcal{f}^{(1)}_{0,1})-\mathcal{f}^{(1)}_{1,1})\big]-v_{-1}^{(0 ) } \mathcal{f}^{(1)}_{1,2}.\end{aligned}\ ] ] therefore @xmath205 where @xmath206 is obtained from @xmath207 replacing the first column with the vector @xmath208 . in order to obtain an explicit formula for @xmath189 and @xmath190 we expand the complete solutions in @xmath209 . this provides the leading contribution of the function @xmath210 for @xmath154 , which corresponds to the large @xmath48 limit . first , we write the expressions for @xmath181 and @xmath182 : @xmath211\textrm{i}_{n_2 } [ t/(2 + 2 x ) ] , \\ \mathcal{f}_{\boldsymbol{n}}^{(1)}(x)&=&x \epsilon ( 4 x+1)^{-n_1/2 } \int_0^\infty~dt~e^{-t } \nonumber \\ & \times&\left[\textrm{i}_{n_1}\left(\frac{t \sqrt{4 x+1}}{2 x+2}\right ) \left(2 n_2 \textrm{i}_{n_2}\left(\frac{t}{2 x+2}\right)+\frac{t \textrm{i}_{n_2 + 1}\left(\frac{t}{2 x+2}\right)}{x+1}\right)-\frac{t \textrm{i}_{n_1 + 1}\left(\frac{t \sqrt{4 x+1}}{2 x+2}\right ) \textrm{i}_{n_2}\left(\frac{t}{2 x+2}\right)}{(x+1 ) \sqrt{4 x+1}}\right].\end{aligned}\ ] ] then , developing in @xmath209 these expressions up to the order @xmath212 , we get @xmath213 , \label{f0x}\ ] ] and @xmath214 . \label{f1x}\ ] ] using the expansions ( [ f0x ] ) and ( [ f1x ] ) in the solutions for @xmath215 and @xmath199 we get @xmath216 finally , using eq . ( [ hx ] ) , we obtain @xmath217 and , thus , the condition on the density @xmath3 , eq . ( [ rhohx ] ) , yields @xmath218 introducing the vacancy density @xmath219 , and considering the case @xmath7 , for the coefficients @xmath40 one has @xmath220 and @xmath221 . \label{aa1}\ ] ] in the high density limit , @xmath222 , the system satisfied by the functions @xmath223 @xmath224 can be linearized , yielding the solutions @xmath225}. \label{solh}\ ] ] substituting eq . ( [ solh ] ) into ( [ aa1 ] ) , and using the definition @xmath42 , one obtains the tracer velocity @xmath226 where we have used the result @xmath227 @xcite . let us notice that eq . ( [ vrho1 ] ) is valid for a general choice of @xmath20 . in particular , using the definition of the probabilities in eq . ( 1 ) of the main text , one immediately recovers the final result reported in eq . ( 13 ) of the letter . we consider a @xmath145dimensional lattice with @xmath228 sites and prepare the @xmath229 particles in a random configuration , with density @xmath230 . in the case @xmath7 for @xmath231 , we used a square lattice with @xmath232 sites , with periodic boundary conditions in both directions , and we checked that results are independent of the box size . in the case @xmath60 , to avoid finite size effects , we used @xmath233 . for @xmath234 , the box linear size is @xmath235 , with periodic boundary conditions . in fig [ fig3 ] we compare analytic and numerical results for the case @xmath234 . in the case @xmath234 , with @xmath236 ( left panel ) and @xmath57 , @xmath58 ( right panel).,title="fig : " ] in the case @xmath234 , with @xmath236 ( left panel ) and @xmath57 , @xmath58 ( right panel).,title="fig : " ]

we study the behavior of the stationary velocity of a driven particle in an environment of mobile hard - core obstacles . based on a lattice gas model , we demonstrate analytically that the drift velocity can exhibit a nonmonotonic dependence on the applied force , and show quantitatively that such negative differential mobility ( ndm ) , observed in various physical contexts , is controlled by both the density and diffusion time scale of obstacles . our study unifies recent numerical and analytical results obtained in specific regimes , and makes it possible to determine analytically the region of the full parameter space where ndm occurs . these results suggest that ndm could be a generic feature of biased ( or active ) transport in crowded environments . _ introduction._quantifying the response of a complex system to an external force is one of the cornerstone problems of statistical mechanics . in the linear response regime , a fundamental result is the fluctuation - dissipation theorem , which relates system response and spontaneous fluctuations . within the last years a great effort has been devoted to generalizations of this theorem to nonequilibrium situations @xcite , when the time reversal symmetry is broken , and also to elucidating the effects of the higher order contributions in the external perturbation @xcite . from experimental perspective , theoretical understanding of the latter issues is of an utmost importance in several fields , such as active microrheology @xcite and dynamics of nonequilibrium fluids @xcite . a striking example of anomalous behavior beyond the linear regime is the negative response of a particle s velocity to an applied force , observed in diverse situations in which a particle subject to an external force @xmath0 travels through a medium . the terminal drift velocity @xmath1 attained by the driven particle is then a nonmonotonic function of the force : upon a gradual increase of @xmath0 , the terminal drift velocity first grows as expected from linear response , reaches a peak value and eventually decreases . this means that the differential mobility of the driven particle becomes negative for @xmath0 exceeding a certain threshold value . such a counter - intuitive `` getting more from pushing less '' @xcite behavior of the differential mobility ( or of the differential conductivity ) has been observed for a variety of physical systems and processes , e.g. for electron transfer in semiconductors at low temperatures @xcite , hopping processes in disordered media @xcite , transport of electrons in mixtures of atomic gases with reactive collisions @xcite , far - from - equilibrium quantum spin chains @xcite , some models of brownian motors @xcite , soft matter colloidal particles @xcite , different nonequilibrium systems @xcite , and also for the kinetically constrained models of glass formers @xcite . apart of these examples , negative differential mobility ( ndm ) has been observed in the minimal model of a driven lattice gas , which captures many essential features of the behavior in realistic systems . in this model one focuses on the dynamics of a hard - core tracer particle ( tp ) which performs a random walk of mean waiting time @xmath2 , biased by an external force @xmath0 , on a lattice containing a bath of hard - core particles ( or `` obstacles '' ) of density @xmath3 , which perform symmetric random walks of mean waiting time @xmath4 . such a system may be viewed as the combination of two paradigmatic models of nonequilibrium statistical mechanics , namely the symmetric and asymmetric exclusion processes , which have been extensively studied to describe heat and particles transport properties @xcite . up to now , only limiting situations of this model have been analyzed . in the case of _ immobile _ bath particles ( @xmath5 ) , it has been argued that for a tracer subject to an external force and diffusing on an infinite percolation cluster , the drift velocity vanishes for large enough values of the force , and therefore ndm occurs @xcite . more recently , ndm was also observed via numerical simulations for low density of immobile particles @xcite and analytically accounted for @xcite , but to the first order in @xmath3 only . surprisingly enough , it appears that ndm is not a specific feature of a frozen distribution of obstacles but also emerges in dynamical environments undergoing continuous reshuffling due to obstacles random motion ( @xmath6 ) . indeed , very recently , numerical analysis performed in @xcite at a specific value of the density revealed that ndm could occur in a 2d driven lattice gas for bath particles diffusing slow enough . in general , the origin of the ndm has been attributed to the nonequilibrium ( called `` frenetic '' ) contributions appearing in the fluctuation - dissipation relation @xcite . as shown earlier in @xcite , due to its interactions with the environment the tp drives such a crowded system to a nonequilibrium steady - state with a nonhomogeneous obstacles density profile . however , the `` nonequilibrium '' condition is clearly not the only necessary condition for the ndm to emerge - in simulations in @xcite this phenomenon is apparent for some range of parameters but it definitely should be absent when the obstacles move sufficiently fast so that the tp sees the environment as a fluid . vs @xmath3 , for @xmath7 ( black circles ) , as revealed by our analytical approach . inset : zoom of the low density region and comparison with the prediction of the linear approximation , eq . ( [ lin_system ] ) ( red line ) , and with asymptotic result , eq . ( [ asymp ] ) ( blue dashed line ) . ] finally , ndm seems to be controlled by both the density @xmath3 and the diffusion time scale @xmath4 of the bath particles . however , a microscopic theoretical analysis of this effect is still lacking . the only available analysis is restricted to the case of immobile obstacles ( in the low density regime ) where , by definition , the bath particles are not perturbed by the tp . in this letter , we reveal the complete scenario of this coupled dynamics providing i ) a scaling argument in the dilute regime that unveils the physical mechanism of ndm , ii ) an analytic analysis of the tp velocity for arbitrary values of system parameters , and iii ) a criterion for the ndm effect to be observed , which shows in particular that for any @xmath3 ndm exists if @xmath4 is large enough ( see fig . [ fig1 ] ) . more precisely , using a decoupling of relevant correlation functions , we derive the force - velocity relation @xmath1 valid for general @xmath3 , @xmath2 , @xmath4 and @xmath0 , and for any dimension @xmath8 . this approximate expression is shown to be exact both in the dilute and in the dense limit and provides results in excellent agreement with numerical simulations for a wide range of parameters . in the low density regime , we recover the exact result obtained in @xcite in the limit @xmath9 and @xmath10 , while in the high density limit our general expression gives back the exact results of @xcite . therefore , our theoretical framework unifies existing asymptotic results @xcite . our analytic result also allows us to quantify the non - trivial nonmonotonic behavior of the velocity with respect to the force , bringing to the fore the central role of the coupling between density and time scales . in particular , we analytically determine in the plane @xmath11 the region for ndm and establish an accurate criterion for the existence of the ndm ( exact at linear order in @xmath3 ) , see fig . [ fig1 ] @xcite . _ model._the dynamics in the system under study is defined as follows . each bath particle , selected at random , waits an exponential time with mean @xmath4 and then selects the jump direction with probability @xmath12 . once the jump direction is chosen , the obstacle attempts to move onto the target site : the move is realized if the target site is empty at this time moment ; otherwise , if the target site is occupied by either another obstacle or the tp - the move is rejected . in a similar fashion , the tp waits an exponential time with mean @xmath2 and then chooses to jump in the direction @xmath13 ( @xmath14 ) with probability @xmath15 where @xmath16 is the inverse temperature ( measured in the units of the boltzmann constant ) , @xmath17 are the corresponding @xmath18 base vectors of the hypercubic lattice , the lattice step has been taken equal to one and we denote @xmath19 . note that ( [ pnu ] ) provides the standard choice of the transition probabilities , which satisfy the generalized detailed balance condition @xcite , but arbitrary choices of @xmath20 @xcite can be considered within our formalism @xcite . before discussing the mathematical details of our approach , we first present a scaling argument that reveals the physical mechanism underlying ndm and provides an estimation of the threshold in the low density limit . assuming a strong external force , one has @xmath21 , @xmath22 with @xmath23 , so that the mean velocity in the absence of obstacles can be written @xmath24 . the stationary velocity in the presence of obstacles is then given by the mean distance @xmath25 travelled by the tp between two obstacles divided by the mean duration of this excursion , which is the sum of the mean time of free motion @xmath26 $ ] and of the mean trapping time @xmath27 per obstacle . the escape from a trap results from two alternative independent events : the tp steps in the transverse direction ( with rate @xmath28 ) or the obstacle steps away ( with rate @xmath29 , for @xmath7 ) . this leads to @xmath30 , and finally @xmath31 from this formula , it can be viewed that @xmath32 is decreasing with @xmath0 at large @xmath0 ( i.e. small @xmath33 ) , and therefore non monotonic with @xmath0 , as soon as @xmath34 . this unveils the physical origin of ndm in the dilute regime , where two effects compete . on the one hand a large force reduces the travel time between two consecutive encounters with bath particles ; on the other hand it increases the escape time from traps created by surrounding particles . eventually , for @xmath4 large enough , such traps are sufficiently long lived to slow down the tp when @xmath0 is increased . in order to get a rigorous and quantitative understanding of ndm for all parameter values , we now analyze in detail the microscopic dynamics of the model . _ general expression of the velocity._ let the boolean variable @xmath35 denote the instantaneous occupation of the site at position @xmath36 by any of the obstacles , @xmath37 denote the instantaneous configuration of all such occupation variables and @xmath38 - the instantaneous position of the driven particle . the stationary velocity @xmath1 along the field direction is easily shown to be given by ( see supplementary material @xcite ) @xmath39 where the coefficients @xmath40 ( @xmath41 ) are defined by the relation @xmath42 . here , @xmath43 represents the stationary density profile around the tp , @xmath44 being the joint probability of finding the tp at the site @xmath38 with the configuration of obstacles @xmath45 . in order to obtain a general expression for the tp stationary velocity for arbitrary force , we make use of the decoupling approximation @xcite for the correlation function of the occupation variables of the form @xmath46 which presumes that the occupation of the site just in front of the tp , and of a site some distance @xmath47 apart of it , become statistically independent . this approach represents a mean - field - like approximation and its physical motivation relies on the observation that a fluctuation in the occupancy of the sites in the vicinity of the tracer does not affect the dynamics far from the tracer itself . this decoupling scheme has been previously used in @xcite to derive general equations for the tp velocity in two - dimensional open systems . however , the analysis in @xcite has only been concerned with the linear response regime , giving access to the stokesian behavior of the mobility and hence , via the einstein relation , to the diffusion coefficient of the particle in the absence of external bias . here we extend this analysis to nonlinear response ( arbitrary force ) and arbitrary dimensionality of the embedding lattice in order to define the physical conditions under which the ndm takes place . following @xcite , this decoupling approximation can be shown to lead to a closed system for the @xmath40 , which is reported in @xcite . this system is highly nonlinear in the coefficients @xmath40 . however , it can be numerically solved to find the analytic value of the tp velocity for an arbitrary choice of the model parameters . _ criterion for ndm._by using our analytical solution , the region for ndm in the plane @xmath11 can be determined , as reported in fig . [ fig1 ] , which constitutes the key result of this letter . importantly , this shows that for every density there exists a value of @xmath48 above which ndm can be observed ; this value diverges for both @xmath49 and @xmath50 . in turn , for any value of @xmath51 , there exists a range of density @xmath52 $ ] , for which ndm occurs . when @xmath48 is sufficiently large , the value of @xmath53 can be made explicit using a small density expansion ( see eqs.([vel_lin])-([lin_system ] ) below ) . this leads to the exact asymptotic result @xmath54 which is validated numerically in fig . [ fig1 ] , see @xcite . note that this exact result is consistent with our earlier scaling argument . in order to validate the above scenario and to explore the effectiveness of the decoupling approximation ( [ approx ] ) , we have performed numerical simulations for different dimensions . a very good agreement is observed for a wide range of parameters ( see fig . [ fig0 ] for a two - dimensional infinite square lattice and @xcite for the three - dimensional case ) . we show below that this approximation is actually exact in both limits @xmath49 ( at linear order in @xmath3 ) and @xmath50 . for @xmath7 and @xmath55 : ( a ) @xmath56 , @xmath57 and different @xmath4 , analytic prediction ( lines ) and numerical simulations ( symbols ) ; ( b ) @xmath57 and @xmath58 , analytic prediction ( continuous lines ) , numerical simulations ( symbols ) and linearized solution ( dashed lines ) ; ( c ) high density limit , @xmath59 , with @xmath57 and different @xmath4 , analytic prediction of eq . ( [ rho1 ] ) ( lines ) and numerical simulations ( symbols ) ; ( d ) @xmath60 , @xmath57 and different @xmath4 , analytic prediction ( lines ) and numerical simulations ( symbols ) . ] _ low density limit . _ in the dilute limit @xmath9 , the system for the coefficients @xmath61 can be drastically simplified ( see @xcite ) . in this case , one has @xmath62 and the tp velocity can be expressed as @xmath63 where the coefficients @xmath64 satisfy the linear system of equations @xmath65v_{\boldsymbol{e}_\nu}\nabla_{-\nu}\mathcal{f}_{\boldsymbol{n } } \nonumber \\ & -&(2d\tau^*/\tau)(p_1-p_{-1})(\nabla_1-\nabla_{-1})\mathcal{f}_{\boldsymbol{n}}. \label{lin_system}\end{aligned}\ ] ] here , the functions @xmath66 depend on the coefficients @xmath61 , on dimension of the system , and are reported explicitly in @xcite , while @xmath67 is a differential operator defined by the relation @xmath68 . the @xmath1 obtained in this dilute limit is reported in fig . [ fig0](b ) ( dashed lines ) for different densities and shows the same behavior as the complete solution , even at intermediate values of @xmath3 , for small enough forces . a further simplification occurs in the limit considered in @xcite of the standard lorentz gas , namely when @xmath69 . in this case , from ( [ lin_system ] ) we obtain an explicit solution , which , as an actual fact , coincides with the analytic results presented in @xcite . in the particular case @xmath7 , the functions @xmath66 simplify to @xmath70 with @xmath71 . substituting eq . ( [ f_inf ] ) into the system ( [ lin_system ] ) , and using eq . ( [ vel_lin ] ) , one recovers the exact result of @xcite ( see @xcite ) . as the accuracy of our analytic results increases when @xmath48 decreases , as shown numerically in fig . [ fig0 ] , we claim that our decoupling approximation , eq . ( [ approx ] ) , is exact at linear order in @xmath3 . _ high density limit._as detailed in @xcite and illustrated here in the particular case @xmath7 , the system for the coefficients @xmath61 linearized around @xmath72 leads to @xmath73}. \label{rho1}\ ] ] this result gives back the exact expression obtained in @xcite in the particular case @xmath74 . _ conclusion._we have presented an analytic theory for ndm in a general driven lattice gas . exploiting a decoupling approximation , we have obtained an analytic expression for the force velocity relation . this expression which goes beyond linear response , is shown to be exact in both @xmath49 and @xmath50 regimes and turns out to be in very good agreement with numerical simulations for a wide range of parameters . in particular , for values of @xmath4 large enough , a nonmonotonic behavior of the tp velocity as a function of the external force is indeed observed . our study extends analytical results obtained in @xcite and sheds light on recent numerical observations @xcite . in particular , with the choice of transition rates of @xcite , which do not depend on the field in the transverse direction , ndm is observed only for much larger values of @xmath48 . this is due to the fact that the escape time of the tp from traps , in that case , is insensitive to the applied force to linear order in @xmath3 . our solution reveals and quantifies a minimal physical mechanism responsible for ndm , which is based on the coupling between the density of obstacles and the diffusion time scales of the tp and obstacles . our minimal model , which takes into account the repulsive part of the particle - particle interactions only , suggests that the phenomenon of the negative differential mobility should be a generic feature of biased transport in crowded environments . the work of o.b . and a.s . is supported by the european research council ( grant no . fptopt-277998 ) . 99 u. marini bettolo marconi , a. puglisi , l. rondoni , and a. vulpiani , phys . rep . * 461 * , 111 ( 2008 ) . l. cugliandolo , j. phys . a * 44 * , 483001 ( 2011 ) . u. seifert , rep . . phys . * 75 * , 126001 ( 2012 ) . g. gradenigo , a. puglisi , a. sarracino , d. villamaina , and a. vulpiani , in _ nonequilibrium statistical physics of small systems : fluctuation relations and beyond _ , eds . : r. klages , w. just and c. jarzynski , ( wiley - vch , weinheim , 2012 ) a. morita , phys . rev . a * 34 * , 1499 ( 1986 ) . j .- p . bouchaud and g. biroli , phys . rev . b * 72 * , 064204 ( 2005 ) . e. lippiello , f. corberi , a. sarracino , and m. zannetti , phys . rev . b * 77 * , 212201 ( 2008 ) ; phys . rev . e * 78 * , 041120 ( 2008 ) . g. diezemann , phys . rev . e * 85 * , 051502 ( 2012 ) . o. bnichou , p. illien , g. oshanin , and r. voituriez , phys . rev . e * 87 * , 032164 ( 2013 ) . p. illien , o. bnichou , c. mejia - monasterio , g. oshanin , and r. voituriez , phys . rev . lett . * 111 * , 038102 ( 2013 ) o. bnichou , a. bodrova , d. chakraborty , p. illien , a. law , c. mejia - monasterio , g. oshanin , and r. voituriez , phys . rev . lett . * 111 * , 260601 ( 2013 ) p. habdas , d. schaar , a. c. levitt , and e. r. weeks , europhys . lett . * 67 * , 477 ( 2004 ) . t. m. squires , and t. g. mason , ann . rev . fluid mech . * 42 * , 413 ( 2009 ) . l. g. wilson , a. w. harrison , a. b. schofield , j. arlt , and w. c. k. poon , j. phys . chem . b * 113 * , 3806 ( 2009 ) . d. j. evans , and g. morriss . _ statistical mechanics of non - equilibrium liquids _ , ( cambridge university press , 2008 ) . n. j. wagner , and j. f. brady , physics today * 62 * , 27 ( 2009 ) . r. k. p. zia , e. l. praestgaard , and o. g. mouritsen , am . j. phys . * 70 * , 384 ( 2002 ) . e. conwell , physics today * 23 * , 35 ( 1970 ) . f. nava , c. canali , f. catellani , g. gavioli , and g. ottaviani , j. phys . c : solid state phys . * 9 * , 1685 ( 1976 ) . c. j. stanton , h. u. baranger , and j. w. wilkins , appl . . lett . * 49 * , 176 ( 1986 ) . x. l. lei , n. j. m. horing , and h. l. cui , phys . rev . lett . * 66 * , 3277 ( 1991 ) . h. bttger and v. v. bryksin , phys . stat . sol . 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type 2 diabetes , while being initially characterized by decreased insulin sensitivity of peripheral tissues , ultimately results in the loss of -cell mass . islet transplantation has the potential to rescue the -cell deficiency observed in both forms of diabetes . a major obstacle to greater use of islet transplantation various studies have demonstrated that most -cell proliferation occurs prior to adolescence [ 26 ] . interestingly , -cell proliferation has been observed in obese and pregnant human populations [ 79 ] . these data suggest that while -cell proliferation is tightly controlled the pathway responsible for proliferation is nonetheless intact and given the proper stimuli can be engaged to induce pancreatic islet -cell expansion . various groups have sought to delineate the molecular pathways responsible for inducing proliferation of adult primary -cells as a potential therapeutic intervention for diabetes . recent studies have shown that the -cell transcription factor nkx6.1 induces -cell proliferation by upregulating expression of the orphan nuclear receptors nr4a1 and nr4a3 [ 10 , 11 ] . these data begin to delineate a molecular pathway capable of inducing -cell proliferation that may be leveraged as a therapeutic for enhancing functional -cell mass in diabetic patients . the cdk5/cdk5r1 complex is highly expressed in neurons and is required for proper central nervous system development and neuronal migration . furthermore , deregulation of the cdk5 kinase has been associated with progression of alzheimer 's disease , breast cancer , and prostate cancer [ 1618 ] . studies have illustrated that activated cdk5 promotes insulin exocytosis and that cdk5 protects against -cell apoptosis [ 2023 ] . here we report that cdk5r1 is upregulated by the orphan nuclear receptors nr4a1 and nr4a3 in primary rat islets . we demonstrate that overexpression of cdk5r1 , and not cdk5 , is sufficient to induce -cell proliferation in the 832/13 ins-1 -cell line and primary rat islets while maintaining insulin content and glucose stimulated insulin secretion . furthermore , we show that cdk5r1 mediated proliferation is dependent on the cdk5 complex kinase activity . finally , we demonstrate that cdk5r1 mediated proliferation correlates with increased phosphorylation of prb , which results in activation of -cell cell cycle machinery through release of e2f transcription factors . we propose that the cdk5r1 mediated -cell proliferation pathway may be harnessed to increase -cell numbers for ultimate islet transplantation therapy . wistar rat breeding pairs were purchased from harlan and maintained on standard chow diet ( teklad 7001 ; harlan ) . male rats were allowed to feed ad libitum and were maintained on a 12-hour light - dark cycle . pancreatic islets were isolated from 5-week - old male rats as previously described [ 2426 ] . all animal studies were approved and performed in accordance with brigham young university 's iacuc guidelines . primary rat islets were cultured in rpmi 1640 and supplemented with 10% fbs , 1% fungizone antimycotic ( life technologies ) , and 1% hepes . , islets were cultured for 48 hours with 10 mol / l roscovitine ( santa cruz ) or dmso ( vehicle , sigma ) . for all islet experiments using adenoviral transduction , viral treatments occurred within four hours of completing the islet isolation procedure as previously published [ 10 , 11 , 26 , 2832 ] . islets were transduced with adenovirus for 18 hours , after which media and adenoviral vectors were removed . all measurements on primary rat islets ( proliferation , survival , and insulin secretion ) occurred 96 hours after islet isolation . adenoviruses expressing nkx6.1 , nr4a1 , nr4a3 , and gfp have been described elsewhere [ 10 , 3439 ] . all recombinant viruses were shown to be replication incompetent by being e1a deficient , using an rt - pcr screen , as previously described . for studies involving adenovirus mediated gene manipulation , pools of 200 islets were transduced with ~2 10 ifu / ml adenovirus ( moi~100200 ) for 18 hours , as previously described [ 10 , 11 , 29 , 32 , 41 , 42 ] . media were changed after 18 hours and islets were cultured for up to 96 hours . assays were completed at 48 , 72 , or 96 hours after harvest depending on the experiment . for apoptosis assays , 832/13 cells were plated at a concentration of 2 10 cells / ml in 24-well plates at 1 ml per well . following 24 hours of incubation , the cells were transduced with ~2 10 ifu / ml adenovirus ( moi~100200 ) of adcmv - gfp , adcmv - cdk5 , or adcmv - cdk5r1 or left untransduced . following 48 hours of culture , the cells were treated with etoposide ( 0.9 m ) , camptothecin ( 2.0 m ) , thapsigargin ( 0.32 mm ) , or dmso for 18 hours . cell viability was determined by comparing the percentage of cells remaining after drug treatment to the percentage of cells after dmso treatment . total caspase-3 and cleaved caspase-3 were measured by western blot analysis of cells transduced with adcmv - gfp or adcmv - cdk5r1 treated with dmso ( no drug ) , camptothecin , etoposide , or thapsigargin . ratio of cleaved caspase-3 versus total caspase-3 was measured and quantified . 832/13 cells were transfected using lipofectamine rnaimax ( life technologies ) with sirna duplexes against rat cdk5 , 5-guucagcccuccgggagautt-3 , or a previously described scrambled control , 5-gagaccctatccgtgatta-3 [ 32 , 34 ] . following an overnight incubation , cells were transduced with adcmv - gfp or adcmv - cdk5r1 or left untreated . rna was harvested to measure extent of cdk5 knockdown by rt - pcr , and proliferation was determined by cell counts . [ methyl - h]-thymidine was added at a final concentration of 1 ci / ml to groups of ~200 islets for the final 48 hours of culture . groups of 20 islets were picked in triplicate and washed twice in rpmi-1640 with unlabeled thymidine and twice in pbs and then the dna was precipitated with 500 l cold 10% trichloroacetic acid and solubilized with addition of 80 l of 0.3 n naoh . [ h]-thymidine incorporation was measured by liquid scintillation counting and normalized to total cellular protein . insulin secretion was measured in triplicate in groups of 20 islets per condition as previously described in secretion assay buffer ( sab ) containing 2.5 mm glucose for 1 hour at 37c ( basal ) followed by incubation in sab containing 16.7 mm glucose for 1 hour ( stimulatory ) . insulin was measured in sab using the coat - a - count kit ( siemens ) . islets were lysed in ripa buffer and total protein was determined by bca ( pierce ) , and insulin content was measured as described . clarified cell lysates were run on 412% nupage gels ( invitrogen ) and transferred to polyvinylidene fluoride ( pvdf ) membranes . membranes were probed with diluted antibodies raised against nkx6.1 ( iowa developmental hybridoma bank , f55a10 ) , gfp ( abcam , ab13970 ) , -tubulin ( sigma , t5326 ) , cdk5r1 ( cell signaling , 2680 ) , cdk5 ( cell signaling , 2506 ) , caspase-3 ( cell signaling , 9665 ) , prb ( cell signaling , 9313 ) , or phosphorylated prb ( cell signaling , 9309 ) . sheep anti - mouse ( 1 : 10,000 ) and goat anti - rabbit ( 1 : 10,000 ) antibodies ( ge healthcare ) coupled to horseradish peroxidase were used to detect the primary antibodies . rna was harvested using the rneasy microkit ( qiagen ) and cdna was synthesized in an iscript reaction ( biorad ) . real - time pcrs were performed using the life technologies one step plus sequence detection system and software ( life technologies ) . taqman - based assay on demand primers and probes ( life technologies ) were used to detect rat cdk5 , cdk5r1 , and peptidylprolyl isomerase a ( ppia , internal control ) . islets were cultured with edu at a concentration of 10 m , with daily media changes , for 96 hours . pools of 50 islets were dispersed and plated on poly - d lysine coated coverslips ( bd ) . five sections containing greater than 400 nuclei were evaluated from edu signal evaluated using imagej software for each experimental condition . previously published microarray data were queried for genes upregulated by nr4a1 and nr4a3 48 hours after adenoviral transduction that were not regulated by nkx6.1 at 24 , 48 , or 96 hours after adenoviral transduction time points . genes were selected by being induced by nr4a1 and nr4a3 , not by nkx6.1 , with 1.5-fold or greater induction and a p value less than 0.05 . gene ontology ( go ) analysis was completed using panther pathway analysis , as described . for statistical determinations , data were analyzed by the paired student 's t - test or by one - way anova with bonferroni post hoc analysis for multiple group comparisons . we have previously shown that overexpression of the -cell transcription factor nkx6.1 is sufficient to induce -cell proliferation . nkx6.1 mediated -cell proliferation is dependent on expression of the nr4a1 and nr4a3 orphan nuclear receptors . using microarray analysis , we have shown that many of the nr4a1 and nr4a3 upregulated genes are also upregulated by nkx6.1 at a later time point . furthermore , knockout of nr4a1 or nr4a3 is sufficient to impede expression of nkx6.1 upregulated genes and abrogate nkx6.1 mediated -cell proliferation , demonstrating nkx6.1 dependence on the nr4a1 and nr4a3 transcription factors . we sought to determine if any of the nr4a1 or nr4a3 upregulated genes is independent of the nkx6.1 proliferation pathway . to address this question , we used data mining techniques to compare the previous published microarray data to define genes that are induced by nr4a1 and nr4a3 but are not included in the nkx6.1 mediated -cell proliferation pathway . using our previously published microarray data we defined genes upregulated by nr4a1 and nr4a3 after 48 hours of expression which are not induced by nkx6.1 at the 24- , 48- , or 96-hour time points . from this analysis , we determined that 114 genes were upregulated by nr4a1 and nr4a3 by 1.5-fold or greater which are not regulated by nkx6.1 . using the panther pathway analysis software , we determined the most highly represented biological functions from our selected genes , based on go terms . from this analysis , we determined that the strongest upregulated go biological functions at 49.5% of our genetic subset ( 54 genes ) were metabolic process ( which consists of 3 genes in biosynthetic process , 9 genes in catabolic process , 1 gene in coenzyme metabolic process , 1 gene in generation of precursor metabolites and energy , 12 genes in nitrogen compound metabolic process , 14 genes in phosphate - containing compound metabolic process , 43 genes in primary metabolic process , and 2 genes in sulfur compound metabolic process ) and at 35.2% ( 42 genes ) were cellular process ( which consists of 13 genes in cell communication , 11 genes in cell cycle , 1 gene in cell proliferation , 6 genes in cellular component movement , 3 genes in chromosome segregation , and 1 gene in cytokinesis ) ( figure 1(a ) ) . as our goal was to determine genes involved in -cell proliferation which are unique to the nr4a nuclear hormone receptors , we queried the cellular processes category for genes associated with the cell cycle . with 43.2% of the subset of genes , the cell cycle go biological function was the second largest category , just behind cell communication at 54.1% ( figure 1(b ) ) . within the cell cycle set of genes , 16 genes were associated with various parts of the cell cycle including cytokinesis , centromere formation , and microtubule formation . among these genes , the cdk5 ligand cdk5r1 was found to be upregulated 1.7-fold by nr4a1 and nr4a3 but not upregulated by nkx6.1 . the binding partner of cdk5r1 , cdk5 , was unregulated by nr4a1 , nr4a3 , and nkx6.1 ( table 1 ) . cdk5r1 , due to its key role as a cdk regulator and the activity of the cdk5 complex in diabetes , was chosen as a potential candidate for further studies . to verify the microarray analysis results , we measured cdk5r1 mrna from primary rat islets . islets were transduced with adcmv - gfp , adcmv - nkx6.1 , adcmv - nr4a1 , or adcmv - nr4a3 or left untreated . total rna was isolated 48 hours after viral transduction . while untreated islets , islets expressing gfp , and islets expressing nkx6.1 had no increased cdk5r1 mrna levels , islets transduced with nr4a1 or nr4a3 had 13.5- and 10.1-fold increase , respectively ( figure 2(a ) ) . in contrast , cdk5 levels do not change when comparing untreated primary rat islets or islets expressing gfp , nk6.1 , nr4a1 , or nr4a3 ( figure 2(b ) ) . overexpression of nr4a1 or nr4a3 is sufficient to induce increased cdk5r1 protein levels ( figure 2(c ) ) . finally , overexpression of nr4a1 and nr4a3 in the same islet population demonstrated no synergistic increase in cdk5r1 protein levels , which is consistent with the highly overlapping transcriptional profiles induced by these transcription factors in primary rat islets ( figure 2(d ) ) . these data demonstrate that cdk5r1 upregulation is unique to nr4a1 and nr4a3 induction and not induced in the nkx6.1 mediated pathway . to determine if cdk5r1 is sufficient to induce islet proliferation , adenoviral vectors expressing cdk5r1 and cdk5 were designed . primary rat islets were cultured without adenoviral transduction or were transduced with adcmv - gfp , adcmv - cdk5 , or adcmv - cdk5r1 at isolation for 24 hours . islets were cultured in the presence of h - thymidine beginning 48 hours after adenoviral transduction and were harvested after 96 hours of culture . islets transduced with adcmv - cdk5r1 demonstrated sixfold induction in cdk5r1 protein level ( figure 3(a ) ) . this resulted in a 2.5-fold induction in islet proliferation rate ( figure 3(b ) ) . in addition , islets transduced with adcmv - cdk5r1 and adcmv - nkx6.1 demonstrated an additive effect in terms of proliferation , suggesting that cdk5r1 overexpression results in the activation of factors that are left unchanged by nkx6.1 alone , potentially demonstrating that different portions of replication competent pathways are in effect ( figure 3(c ) ) . furthermore the inability of cdk5 overexpression to induce proliferation in primary rat islets suggests that either cdk5r1 is acting in a cdk5 independent manner or sufficient cdk5 protein levels are present in the islet and that addition of cdk5r1 is necessary to activate the cdk5-cdk5r1 proliferation pathway resulting in induction of proliferation . our data demonstrate that cdk5r1 overexpression drives proliferation in primary rat islets . to determine if -cells specifically replicate in response to cdk5r1 overexpression , we cultured primary rat islets transduced with adcmv - gfp or adcmv - cdk5r1 with the thymidine analog edu . islets were cultured in the presence of edu for 96 hours , after which islets were dispersed and the percentage of insulin+edu+ and insulinedu+ cells were calculated . our findings demonstrate that untransduced islets and islets transduced with adcmv - gfp had less than 1% of cells positive for edu in the insulin positive and insulin negative populations ( figures 4(a)4(c ) ) . in contrast , islets transduced with adcmv - cdk5r1 had 8.57% insulin+edu+ cells and 2.80% insulinedu+ cells ( figures 4(a ) and 4(c ) ) . furthermore , given that the majority of proliferation is observed in -cells and not -cells suggests that -cells may express a higher level of cdk5 than the other islet endocrine cells . knockdown of cdk5 and cdk5r1 has been shown to result in enhanced caspase-3 cleavage and induction of apoptosis in the 832/13 ins-1 cell line . based on these findings , we hypothesized that overexpression of cdk5r1 would result in protection against apoptotic stimuli such as etoposide , thapsigargin , and camptothecin . to determine the effect of cdk5r1 overexpression on these inducers of apoptosis , untreated cells were compared to cells transduced with adcmv - gfp , adcmv - cdk5 , or adcmv - cdk5r1 . following a 48-hour culture , the cells were exposed to doses of etoposide , thapsigargin , or camptothecin for 18 hours . cell viability assays demonstrated that cdk5r1 overexpression protected 832/13 ins-1 cells treated with thapsigargin or etoposide as compared to untreated cells or cells transduced with adcmv - gfp or adcmv - cdk5 ( figure 5(a ) ) . this demonstrates that cdk5r1 overexpression protects -cells from ca induced er stress and topoisomerase ii inhibitor induced apoptosis . interestingly , no protection was observed with cdk5r1 or cdk5 in cells treated with camptothecin , an inhibitor of topoisomerase i ( figure 5(a ) ) . in addition to measuring cell viability through cell counts , we also measured total and cleaved caspase-3 levels . we demonstrated that cells treated with adcmv - gfp had significantly higher levels of cleaved caspase-3 than cells transfected with adcmv - cdk5r1 when both cell types were treated with thapsigargin or etoposide . cells treated with camptothecin showed no decrease in cleaved caspase-3 levels , supporting our cell viability data for cdk5r1 and this compound . taken together , these data demonstrate that overexpression of cdk5r1 can protect -cellsagainst selected apoptotic stimuli and inhibits caspase-3 activation . various studies have demonstrated that induction of -cell proliferation is frequently accompanied by decreased insulin secretion [ 45 , 46 ] . furthermore , recent studies have demonstrated a connection between the cdk5 kinase complex and insulin secretion rates . therefore , we sought to determine the effect of cdk5r1 overexpression on -cell insulin content and secretion . islets were transduced overnight with adcmv - gfp , adcmv - cdk5 , or adcmv - cdk5r1 and subsequently cultured for 96 hours . total insulin content of islet populations was measured , and no significant difference was observed between the three treated populations and the untreated controls ( figure 6(a ) ) . similarly , secreted insulin was measured from adenoviral treated or untreated control islets cultured in the presence of low ( 2.8 mm ) and high ( 16.7 mm ) glucose concentrations . these data also demonstrate that the adenoviral treated islets have similar insulin secretion to the untreated controls ( figure 6(b ) ) . taken together , these data demonstrate that cdk5r1 overexpression in primary rat islets , following a 96-hour incubation period , results in maintenance of insulin content and insulin secretion . the primary function of cdk5r1 is to serve as the binding partner of cdk5 , thus activating the cdk5 : cdk5r1 kinase activity . we therefore hypothesized that cdk5r1 mediated proliferation is dependent on cdk5 kinase activity . to test this hypothesis , islets were transduced with adcmv - gfp , adcmv - cdk5 , or adcmv - cdk5r1 at isolation and compared to untreated islets . islets were cultured in the presence of h - thymidine 48 hours after isolation and were harvested 96 hours after isolation . 72 hours after isolation , the cdk5 inhibitor roscovitine was added for a 24-hour period . roscovitine , while being able to inhibit other cdks such as cdk2 ( ic50 of 0.7 m ) and cdc2 ( ic50 of 0.65 m ) , has a high affinity for cdk5 ( ic50 of 0.16 m ) . uninfected adcmv - gfp and adcmv - cdk5 treated islets showed no changes in proliferation rate when treated with roscovitine . islets transduced with adcmv - cdk5r1 had the expected induction in proliferation , which was decreased to control levels when cultured with roscovitine ( figure 7(a ) ) . these data demonstrate that cdk5r1 mediated proliferation is dependent on the cdk5 : cdk5r1 kinase activity , and that cdk5r1 is essential for this kinase to be activated in primary rat -cells . to determine if knockdown of cdk5 is sufficient to inhibit the proliferative capacity of cdk5r1 , we used sirna mediated cdk5 knockdown in the ins-1 832/13 -cell line . using a sicdk5 sequence that has previously been shown to be sufficient to knockdown cdk5 expression in the ins-1 cell line , we were able to successfully decrease cdk5 mrna expression by 75% ( figure 7(b ) ) . cells were transfected with sicdk5 or a scrambled sirna sequence ( sictrl ) , and 24 hours later the cells were transduced with adcmv - gfp or adcmv - cdk5r1 . cells transduced with adcmv - cdk5r1 and transfected with sictrl had a significant increase in proliferation ( figure 7(c ) ) . interestingly , cells that were transfected with sicdk5 and transduced with adcmv - cdk5r1 had a significant decrease in the proliferation rate . these data support the roscovitine data in demonstrating using a genetic ablation model that cdk5r1 mediated proliferation is dependent on the cdk5 kinase activity . cdk5 : cdk5r1 has been shown to phosphorylate prb , which is sufficient to engage the cell cycle machinery through release of e2f1 and family members in various cell types [ 48 , 49 ] . we hypothesized that the cdk5r1 mediated proliferation may be dependent on prb phosphorylation , which would then engage the cell cycle machinery and permit -cell proliferation . first , we measured the phosphorylated prb and total prb levels in untreated islets and islets transduced with adcmv - gfp , adcmv - cdk5 , and adcmv - cdk5r1 . our data demonstrate that while prb levels do not significantly change with transduction of any of the adenoviral constructs , the phosphorylated level of prb significantly increased in islets transduced with adcmv - cdk5r1 ( figure 8(a ) ) . interestingly , culture of islets in the presence of roscovitine significantly decreased the phosphorylation level of prb in the adcmv - cdk5r1 transduced islets ( figure 8(b ) ) . this data demonstrates that cdk5r1 increases the p - prb level in a cdk5 dependent manner . these data suggest that cdk5 : cdk5r1 mediated phosphorylation of prb may be essential for cdk5r1 mediated -cell proliferation . control of -cell replication is a highly regulated process , with the majority of -cell replication occurring during embryogenesis and during the neonatal period . studies have shown , however , that adult -cell expansion does occur during obesity and pregnancy [ 8 , 9 , 23 ] . these data demonstrate that this tightly controlled process is intact in -cells and suggest that defining the molecular components of the -cell proliferation cascade may be used to determine entry points , whereby -cell replication can be induced . these pathways could be leveraged to treat diabetes by inducing -cell replication ex vivo for islet transplantation or in vivo for expansion of endogenous -cell mass . therefore , it is imperative to define the molecules involved in known -cell proliferation pathways . we have previously shown that the nkx6.1 mediated -cell proliferation pathway is dependent on the orphan nuclear receptors nr4a1 and nr4a3 [ 10 , 11 ] . many of the genes upregulated in the nkx6.1 pathway are directly regulated through the transcriptional activity of nr4a1 and nr4a3 . interestingly , upon comparing the gene expression profiles for nkx6.1 treated islets with nr4a1 or nr4a3 treated islets , it is clear that there is a significant subset of genes induced by nr4a1 and nr4a3 that are not regulated in the defined nkx6.1 proliferation pathway . from this subset of genes we have demonstrated that the unique cell cycle activator cdk5r1 is upregulated by nr4a1 and nr4a3 and that cdk5r1 is sufficient to induce proliferation of primary rat -cells and 832/13 ins-1 cells while maintaining gsis . furthermore , we have shown that overexpression of cdk5r1 in 832/13 ins-1 cells protects against apoptosis induced by thapsigargin and etoposide but not camptothecin . finally , we have shown that the cdk5r1 dependent increase in -cells proliferation is dependent on the cdk5 : cdk5r1 kinase activity . the increase in proliferation corresponds with increased phosphorylation of the cell cycle inhibitor prb , which results in release and activation of e2f family members . these data demonstrate that expression of cdk5r1 is sufficient to induce -cells proliferation by releasing a cell cycle braking mechanism ( figure 9 ) . expression of cdk5 and cdk5r1 was first observed in neuronal cells [ 14 , 50 ] . recent studies have clearly demonstrated that both factors are expressed in primary -cells [ 13 , 27 ] . since the observation that both cdk5 and cdk5r1 are expressed in -cells , much work has been done to address their function in normal and diseased -cells [ 23 , 44 , 46 ] . to date , while other groups have looked at the effect of the cdk5 complex on glucose stimulated insulin secretion and cellular apoptosis , we are the first to show that cdk5r1 overexpression and activation of the cdk5 : cdk5r1 complex result in increased -cell proliferation . our data demonstrates that overexpression of cdk5r1 in primary rat islets results in increased -cell proliferation and that there is no significant increase in proliferation of other non - insulin expressing islet cells . given that cdk5r1 activates the cdk5 kinase complex , these data suggest that -cells and other islet endocrine cells may not express appreciable levels of cdk5 . while no studies have been published to determine the cdk5 expression level in the non - insulin expressing endocrine cells , our data supports the hypothesis that cdk5 expression may be sequestered to -cells , thus explaining why overexpression of cdk5r1 induces proliferation in only the insulin expressing islet population . furthermore , endogenous levels of cdk5r1 appear to be very low in -cells ( figure 2(c ) ) . we propose that the low levels of endogenous cdk5r1 keep the cdk5 complex in an inactive state . this is typical of cyclin - dependent kinase family , of which cdk5 is a member . several groups have studied the role of the cdk5 kinase complex on insulin secretion . within these studies , there are some contradictory findings . early findings demonstrated that cdk5 overexpression enhanced insulin secretion from -cells by facilitating vesicle fusion . latter studies presented data that cdk5 kinase activity is increased in -cells after culturing with elevated glucose and cytokine levels and that this increase results in decreased insulin gene expression and secretion [ 22 , 44 , 51 ] . our findings demonstrate that overexpression of cdk5r1 in primary rat islets maintains glucose stimulated insulin secretion and that total insulin levels are maintained . our studies were in primary rat islets that were cultured for 96 hours after adenoviral transduction . many of the other studies were completed primarily in cell lines or used short - term culture conditions [ 22 , 27 , 44 , 51 ] . we did not culture our islets under damaging conditions , such as long - term elevated glucose , or in the presence of cytokines . while our studies were not conducted in a way to determine the effect of endogenous cdk5r1 in a diseased -cell state , they do clearly demonstrate that cdk5r1 overexpression is sufficient to induce -cell proliferation while maintaining insulin content and the glucose stimulated insulin secretion response . in addition to studying the effect of the cdk5 complex on insulin secretion , other groups have studied the effect on protection from apoptosis . an early study showed in the min-6 cell line that overexpression of cdk5r1 and culture with high glucose resulted in increased apoptosis . a subsequent study using iapp and -1 integrin signal blockade as induction for -cell apoptosis demonstrated that cdk5 and cdk5r1 were necessary for protection against apoptosis . our data , using cdk5r1 overexpression , demonstrates that while no protection was observed for apoptosis induced by camptothecin , a significant level of protection was observed in cells overexpressing cdk5r1 that were treated with etoposide or thapsigargin . while the studies with min-6 cells measured cdk5r1 induced apoptosis , our studies indicated no increase in basal death rates . furthermore , our studies indicated protection against apoptotic stimuli , which was not measured in the previous study . these data demonstrate that cdk5r1 overexpression is sufficient to confer protection to select apoptotic stimuli in addition to enhancing cellular replication . each of the apoptotic inducing compounds used in this study has a unique mechanism by which it induces apoptosis . thapsigargin blocks the serca pumps , thus increasing cytosolic ca levels and inducing er stress . neuroblastoma cells treated with camptothecin had attenuated apoptosis levels when also treated with the cdk5 inhibitor roscovitine . these data demonstrate that cdk5 kinase activity is needed for camptothecin - induced apoptosis , which correlates with our findings that cdk5r1 overexpression fails to confer protection . studies using etoposide have demonstrated that cdk5r1 sequestration by c53 results in enhanced apoptosis and c53 deletion resulted in protection to etoposide induced apoptosis . finally , a recent study demonstrated that pc12 cells treated with the serca inhibitor thapsigargin had potentiation of apoptosis when coupled with roscovitine treatment , demonstrating the role of the cdk5 complex to inhibit ca flux . our data do not define a mechanism by which cdk5 kinase activity confers a protective effect against thapsigargin or etoposide induced apoptosis ; however a recent study demonstrated that the proapoptotic protein noxa is phosphorylated by the cdk5 kinase complex , which results in decreased apoptosis . future studies will address the mechanism by which cdk5r1 overexpression protects against these apoptotic stimuli . various studies have shown that the activated cdk5 complex can phosphorylate prb [ 48 , 55 , 56 ] . e2f family members , such as e2f1 , e2f2 , and e2f3 , are critical for engaging the cell cycle by upregulating expression of key genes such as cyclin e , cyclin a , and cyclin b . studies using neuronal cell lines have shown that cdk5 mediated phosphorylation of prb results in reengagement of the cell cycle and induction of neuronal apoptosis [ 48 , 55 ] . this is in contrast to our findings that prb phosphorylation is correlated with increased proliferation rates . previous studies that overexpressed e2f family members in primary -cells have failed to observe enhanced apoptosis rates [ 57 , 58 ] . these previous findings and our presented data demonstrate that while the default for cdk5 mediated cell cycle entry in postmitotic neurons may be induction of apoptotic pathways , the same pathway in -cells results in cell cycle reentry and cellular proliferation . our data clearly demonstrate that cdk5r1 has relatively low expression in -cells under normal conditions . our data demonstrate that overexpression of nr4a1 or nr4a3 is sufficient to induce expression of cdk5r1 and that overexpression of cdk5r1 is sufficient to induce -cell proliferation . studies from other groups have demonstrated that cdk5r1 expression is elevated under high glucose culture conditions [ 44 , 51 ] . these data are consistent with a proposed role for nr4a1 and nr4a3 as cellular nutrient sensors . expression and activity of the nr4a orphan nuclear receptors have been shown to increase in various tissues when cultured with elevated glucose , free fatty acid , cholesterol , and amino acid levels [ 59 , 60 ] . these findings suggest that cdk5r1 expression may increase during the early stages of type 2 diabetes , presumably through glucose mediated activation of the nr4a orphan nuclear receptors . during this pathological period , increases in -cell proliferation have been observed [ 79 , 23 ] , presumably due to the elevated blood glucose level . our data may suggest a mechanism by which the initial elevated blood glucose levels increase nr4a nuclear receptor expression and activity , thus leading to induction of cdk5r1 expression and the initial proliferation observed during this period of disease progression . our findings demonstrate for the first time that overexpression of cdk5r1 is sufficient to induce -cell proliferation . this is a novel finding that suggests potential uses for ex vivo expansion of -cell mass for islet transplantation or in vivo induction of endogenous -cell proliferation . defining the complete cadre of cdk5 kinase -cell targets will be essential for understanding the activity of this kinase complex for inducing -cell proliferation . in conclusion , our findings demonstrate that the orphan nuclear receptors nr4a1 and nr4a3 induce expression of the novel cell cycle activator cdk5r1 independent of the nkx6.1 signaling pathway . we demonstrate that cdk5r1 is sufficient to induce -cell proliferation in the 832/13 ins-1 derived cell line and in primary rat islets . we show that cdk5r1 results in -cell specific proliferation and that this proliferation is dependent on the cdk5 : cdk5r1 kinase complex activity . finally , we demonstrate that cdk5r1 induced -cell proliferation corresponds with increased phosphorylation of the cell cycle inhibitor prb ( figure 9 ) . these data demonstrate that expression of cdk5r1 results in activation of endogenous levels of cdk5 in -cells resulting in prb phosphorylation and activation of cell cycle progression . therefore , our results demonstrate that activation of the novel cdk5 : cdk5r1 cell cycle kinase may be used as a potential therapeutic entry point for increasing -cell mass ex vivo for islet transplantation therapy or expansion of endogenous -cell mass in vivo as a treatment for diabetes . this is the first time that overexpression of cdk5r1 has been shown to be sufficient to induce primary -cell proliferation . future studies will address how overexpression of nr4a family members results in activation of cdk5r1 and other phosphotargets of the cdk5-cdk5r1 kinase complex .

decreased -cell mass is a hallmark of type 1 and type 2 diabetes . islet transplantation as a method of diabetes therapy is hampered by the paucity of transplant ready islets . understanding the pathways controlling islet proliferation may be used to increase functional -cell mass through transplantation or by enhanced growth of endogenous -cells . we have shown that the transcription factor nkx6.1 induces -cell proliferation by upregulating the orphan nuclear hormone receptors nr4a1 and nr4a3 . using expression analysis to define nkx6.1-independent mechanisms by which nr4a1 and nr4a3 induce -cell proliferation , we demonstrated that cyclin - dependent kinase 5 regulatory subunit 1 ( cdk5r1 ) is upregulated by nr4a1 and nr4a3 but not by nkx6.1 . overexpression of cdk5r1 is sufficient to induce primary rat -cell proliferation while maintaining glucose stimulated insulin secretion . overexpression of cdk5r1 in -cells confers protection against apoptosis induced by etoposide and thapsigargin , but not camptothecin . the cdk5 kinase complex inhibitor roscovitine blocks islet proliferation , suggesting that cdk5r1 mediated -cell proliferation is a kinase dependent event . overexpression of cdk5r1 results in prb phosphorylation , which is inhibited by roscovitine treatment . these data demonstrate that activation of the cdk5 kinase complex is sufficient to induce -cell proliferation while maintaining glucose stimulated insulin secretion .

chronic obstructive pulmonary disease ( copd ) is now considered as a respiratory disease with systemic manifestations.1 copd first affects the lungs primarily , and then structural and functional changes also take place in other organs . the degree of airflow limitation as defined by forced expiratory volume in 1 second ( fev1 ) has been used as an index of disease severity , partly because of its significant relationship with mortality.2,3 guidelines indicate that some multidimensional staging systems including systemic components in addition to airflow limitation may be used to assess disease severity,1,4 although the definition of disease severity remains elusive . the bode index , incorporating measurements of nutrition , airflow limitation , dyspnea , and exercise capacity , has been established for multidimensional staging.5 it is useful in predicting mortality and hospitalizations and in reflecting disease modification and progression.6 more simplified indices such as the ado index , composed of age , dyspnea , and airflow limitation,7 and the dose index , composed of dyspnea , airflow limitation , smoking status , and exacerbation frequency,8 have been developed recently and have been validated . in two european cohorts , both the ado index and the updated bode index significantly predicted the 3-year mortality risk after the first hospital admission due to an exacerbation of moderate - to - severe copd , although the original bode index did not accurately predict such a risk.7 the dose index was related to a range of clinically important outcomes of copd such as health status , hospital admission , or respiratory failure , and was predictive of exacerbations.8 although some multidimensional staging systems have been developed recently , these indices have rarely been compared . more information about the properties of these indices or relationships is needed so that they can be better used in clinical practice or trials and , furthermore , be adopted concretely in the guidelines in future . we hypothesized that the bode , ado , and dose indices would be useful as predictors of mortality in copd , but that they would have some different characteristics . we previously examined the factors related to 5-year mortality using multiple measurements in patients with copd.9 in the present study , by reviewing those data , we analyzed the discriminative and predictive properties of those multidimensional indices in patients with copd . we previously recruited 150 consecutive male outpatients with copd and analyzed factors related to mortality.9 entry criteria included ( 1 ) smoking history of more than 20 pack - years , ( 2 ) maximal fev1/forced vital capacity ratio of less than 0.7 and prebronchodilator fev1 of less than 80% of the predicted value , ( 3 ) regular attendance at kyoto university , kyoto , japan , outpatient clinic over 6 months , ( 4 ) no uncontrolled comorbidities , and ( 5 ) no copd exacerbations over the preceding 6 weeks . pulmonary function tests were performed at least 12 hours after the withdrawal of inhaled bronchodilators.9 patients performed spirometry at 15 and 60 minutes after inhaling salbutamol ( 400 g ) and ipratropium bromide ( 80 g ) using a metered - dose inhaler with a spacer device . exercise tests were performed on symptom - limited progressive cycle ergometry 60 minutes after the inhalation of bronchodilators as described in detail previously.911 patients wore a face mask and began unloaded pedaling for 3 minutes , after which the workload was increased progressively by an increment of 1 w every 3 seconds to the limit of tolerance . predicted values were calculated using the standard equation.12,13 dyspnea was evaluated by the japanese version of the modified medical research council ( mrc ) dyspnea scale , which is a 5-point scale ( 04 ) based on degrees of various physical activities that precipitate dyspnea.14,15 higher scores on the mrc indicate more severe dyspnea . health status was assessed by the japanese version of the st . george s respiratory questionnaire ( sgrq).9,16,17 the sgrq consists of 50 items divided into the three components of symptoms , activity , and impacts , and the total score was calculated with scores ranging from 0 to 100 . the bode index was principally based on the original report5 whose score comprises the body mass index ( bmi ) , percentage of the predicted fev1 , dyspnea by the mrc , and 6-minute walking distance ( 6mwd ) as an exercise capacity component . scores ranged from 0 ( best status ) to 3 ( worst status ) for fev1 and mrc , and 0 or 1 for bmi . in the present study , we employed the modified bode index ( mbode ) , which used vo2 as % predicted , as tested by the progressive cycle ergometry instead of the 6mwd , and was previously developed and validated.18,19 the % predicted was scored as follows : score 0 for > 70% predicted , score 1 for 60%69% predicted , score 2 for 40%59% predicted , and score 3 for 40<% predicted . points for each component were added together so that the mbode index ranged from 0 to 10 . the ado index was calculated based on the original report,7 with the score comprising age , dyspnea by the mrc , and fev1 . scores ranged from 0 ( best status ) to 5 ( worst status ) for age , 03 for mrc , and 02 for fev1 . points for each component were added so that the ado index ranged from 0 to 10 . the dose index was calculated primarily based on the original report,8 with scores comprising dyspnea by the mrc , fev1 , smoking status , and exacerbation frequency per year . scores ranged from 0 ( best status ) to 3 ( worst status ) for mrc , 02 for fev1 and the exacerbation frequency , and 0 or 1 for smoking status . in the present study , the modified dose ( mdose ) index was calculated using the question during the last year , how many severe or very unpleasant attacks of chest trouble have you had ? on the sgrq , instead of exacerbation frequency over the previous year as indicated in the original manuscript.8 points for each component were added so that the dose index ranged from 0 to 8 . relationships between the mbode , ado , and mdose indices were analyzed by spearman s correlation coefficient tests . univariate and multivariate cox proportional hazards analyses were performed to investigate the relationships between the clinical measurements and mortality . results of regression analyses were presented in terms of estimated relative risks ( rr ) with corresponding 95% confidence intervals . we previously recruited 150 consecutive male outpatients with copd and analyzed factors related to mortality.9 entry criteria included ( 1 ) smoking history of more than 20 pack - years , ( 2 ) maximal fev1/forced vital capacity ratio of less than 0.7 and prebronchodilator fev1 of less than 80% of the predicted value , ( 3 ) regular attendance at kyoto university , kyoto , japan , outpatient clinic over 6 months , ( 4 ) no uncontrolled comorbidities , and ( 5 ) no copd exacerbations over the preceding 6 weeks . pulmonary function tests were performed at least 12 hours after the withdrawal of inhaled bronchodilators.9 patients performed spirometry at 15 and 60 minutes after inhaling salbutamol ( 400 g ) and ipratropium bromide ( 80 g ) using a metered - dose inhaler with a spacer device . exercise tests were performed on symptom - limited progressive cycle ergometry 60 minutes after the inhalation of bronchodilators as described in detail previously.911 patients wore a face mask and began unloaded pedaling for 3 minutes , after which the workload was increased progressively by an increment of 1 w every 3 seconds to the limit of tolerance . predicted values were calculated using the standard equation.12,13 dyspnea was evaluated by the japanese version of the modified medical research council ( mrc ) dyspnea scale , which is a 5-point scale ( 04 ) based on degrees of various physical activities that precipitate dyspnea.14,15 higher scores on the mrc indicate more severe dyspnea . george s respiratory questionnaire ( sgrq).9,16,17 the sgrq consists of 50 items divided into the three components of symptoms , activity , and impacts , and the total score was calculated with scores ranging from 0 to 100 . the bode index was principally based on the original report5 whose score comprises the body mass index ( bmi ) , percentage of the predicted fev1 , dyspnea by the mrc , and 6-minute walking distance ( 6mwd ) as an exercise capacity component . scores ranged from 0 ( best status ) to 3 ( worst status ) for fev1 and mrc , and 0 or 1 for bmi . in the present study , we employed the modified bode index ( mbode ) , which used vo2 as % predicted , as tested by the progressive cycle ergometry instead of the 6mwd , and was previously developed and validated.18,19 the % predicted was scored as follows : score 0 for > 70% predicted , score 1 for 60%69% predicted , score 2 for 40%59% predicted , and score 3 for 40<% predicted . points for each component were added together so that the mbode index ranged from 0 to 10 . the ado index was calculated based on the original report,7 with the score comprising age , dyspnea by the mrc , and fev1 . scores ranged from 0 ( best status ) to 5 ( worst status ) for age , 03 for mrc , and 02 for fev1 . points for each component were added so that the ado index ranged from 0 to 10 . the dose index was calculated primarily based on the original report,8 with scores comprising dyspnea by the mrc , fev1 , smoking status , and exacerbation frequency per year . scores ranged from 0 ( best status ) to 3 ( worst status ) for mrc , 02 for fev1 and the exacerbation frequency , and 0 or 1 for smoking status . in the present study , the modified dose ( mdose ) index was calculated using the question during the last year , how many severe or very unpleasant attacks of chest trouble have you had ? on the sgrq , instead of exacerbation frequency over the previous year as indicated in the original manuscript.8 points for each component were added so that the dose index ranged from 0 to 8 . results were expressed as mean standard deviation , unless otherwise stated . relationships between the mbode , ado , and mdose indices were analyzed by spearman s correlation coefficient tests . univariate and multivariate cox proportional hazards analyses were performed to investigate the relationships between the clinical measurements and mortality . results of regression analyses were presented in terms of estimated relative risks ( rr ) with corresponding 95% confidence intervals . baseline characteristics of the 150 male patients with stable copd are shown in table 1 and elsewhere.9 their average age was 69 7 years and the postbronchodilator fev1 was 47.4% 17.4% predicted . the frequency distributions of mbode , ado , and mdose scores are shown in figure 1 . the ado scores were more narrowly distributed than the mbode scores , with 55 patients ( 37% ) and 42 patients ( 28% ) scoring 3 and 4 , respectively . the median of the mdose score was 2 , with the distribution of scores tending to skew toward the lower scores . there were significant relationships between the three indices ( mbode vs ado , correlation coefficients [ rs ] = 0.60 , p < 0.0001 ; ado vs mdose , rs = 0.55 , p < 0.0001 ; and mdose vs mbode , rs = 0.64 , p < 0.0001 ) . of the 150 patients enrolled , six were unavailable for follow - up and 31 patients died.9 causes of death were as follows : 20 due to copd or copd - related diseases , four due to malignant disorders ( two lung cancer cases ) , one due to myocardial infarction and hepatic failure , respectively , and five due to unknown reasons . univariate cox proportional hazards analyses were performed to investigate the relationship between clinical indices and mortality ( table 2 and elsewhere9 ) . age , bmi , fev1 , peak vo2 , mrc , and the sgrq total score were all significantly related to mortality . all the mbode , ado , and mdose indices were strongly related to mortality ( rr = 1.618 , p < 0.0001 ; rr = 2.342 , p < 0.0001 ; and rr = 1.521 , p = 0.0002 , respectively ) . to investigate the abilities of the aforementioned three multidimensional staging methods to predict mortality as compared with airflow limitation , exercise capacity , dyspnea , and health status , multivariate cox proportional hazards analyses were performed ( table 3 ) . model 1 includes three analyses investigating the relationships between each index and fev1 with mortality . the mbode and ado indices were more significantly related to mortality than fev1 , but mdose index was not . model 3 includes three analyses investigating the relationships between each index and mrc with mortality . these results indicate that predictive properties of mbode and ado indices might be stronger than those of fev1 and mrc as well as mdose index . in contrast , model 2 includes three analyses investigating the relationships between each index and peak vo2 with mortality . peak vo2 was more significantly related to mortality than all three indices ( p < 0.0001 ) , indicating that the predictive property of exercise capacity might be stronger than different multidimensional staging . model 4 includes three analyses investigating the relationships between each index and sgrq with mortality . in contrast with model 2 , all three indices were more significantly related to mortality than the sgrq total score . to investigate which of the mbode , ado , and mdose indices was the most significantly correlated with mortality , stepwise multivariate cox proportional hazards analysis was performed ( table 4 ) . both the mbode and ado indices were significantly related to mortality ( rr = 1.351 , p = 0.027 ; and rr = 1.653 , p = 0.031 ) but not the mdose index ( p = 0.87 ) . we evaluated the predictive and discriminative properties of different multidimensional staging systems in patients with copd . among the mbode , ado , and mdose indices , the mbode index seemed to have the best discriminative property . we found that all three indices were significantly predictive of mortality , although the predictive ability of the mdose tended to be inferior to the other two . in contrast , values for the peak vo2 on progressive cycle ergometry were more significantly correlated with mortality than any of the three multidimensional staging systems . we previously examined predictors of mortality in patients with copd and reported that exercise capacity , dyspnea , and health status were significantly related to mortality independently of airflow limitation.9,20,21 these results suggested the need to incorporate these systemic elements in addition to fev1 in evaluating patients with copd . among the three indices , the mbode and ado indices were more strongly predictive of mortality than fev1 , mrc , or sgrq . thus , these multidimensional staging systems seem to be more useful in prognostic assessments than airflow limitation , dyspnea , or health status alone in patients with copd . after evaluating their properties well in different study situations the relationships between the mbode , ado , and mdose indices were moderate , indicating that they do not necessarily evaluate the same aspects of copd , although some components are common to all three indices . in fact , the stepwise multivariate cox proportional hazards analysis showed that both the mbode and ado indices were independently related to mortality in patients with copd . thus , using more than one index might have some complementarily or additive advantage in prognostic assessment . there were differences in the discriminative properties among the mbode , ado , and mdose indices . the mbode score was more widely and normally distributed than the scores of the other indices examined , indicating its superior discriminative property . in our single population sample , the age component of the ado index might have varied less widely than the original report of the ado index,7 as shown here that about 65% of our patients scored 3 or 4 . regarding the mdose index , firstly , its range from 0 to 8 is narrower than the bode and ado indices ranging from 0 to 10 . secondly , in the present study , the median score on the mdose index was low at 2 , and its distribution was skewed toward lower scores , which were consistent with the original report.8 thus , although the ado and dose indices are simple and easy assessments for use in primary care settings , as they do not include an exercise capacity component , their discriminative properties may be limited . in the present study , peak vo2 was more strongly related to mortality than the mbode , ado , and mdose indices , indicating that peak vo2 is an important factor in copd in relation to mortality . in addition to studies examining predictors of mortality in copd,9 peak vo2 is reported to be a useful prognostic factor in other disorders22,23 such as interstitial lung diseases,24 primary pulmonary hypertension,25 cyctic fibrosis,26 or chronic heart failure.27 cardiopulmonary exercise testing has some utility in diagnosis and functional evaluation , and prognostic stratification is considered to be a major indication for cardiopulmonary exercise testing in patients with pulmonary or cardiac disorders.23 in the present study , we compared different multidimensional staging systems from the viewpoint of the relationship of their scores with mortality . although these or similar indices are sometimes referred to as disease severity indices , strictly speaking , disease severity in copd has not been defined . when disease severity is considered according to the closeness of death , however , there are other ideas about defining disease severity , such as its relationship with health status or exacerbations . it seems that multidimensional staging is superior to the current means of disease staging based on the level of fev1.28,29 a standardized definition of disease severity is needed to eliminate confusion and to officially establish a novel disease severity staging system not based solely on fev1 in future . as a limitation , although several multidimensional staging systems in addition to the bode , ado , and dose indices have been developed in recent years,30,31 we did not assess them in the present study . we demonstrated that the multidimensional staging systems of the mbode , ado , and mdose indices were significant predictors of mortality in patients with copd . an understanding of the properties or characteristics of the indices is important when using them in clinical practice , and , at the same time , a definition of disease severity needs to be established in order to propose the indices assessed in this report as a new disease severity index .

backgroundchronic obstructive pulmonary disease ( copd ) is considered to be a respiratory disease with systemic manifestations . some multidimensional staging systems , not based solely on the level of airflow limitation , have been developed ; however , these systems have rarely been compared.methodswe previously recruited 150 male outpatients with copd for an analysis of factors related to mortality . for this report , we examined the discriminative and prognostic predictive properties of three copd multidimensional measurements . these indices were the modified bode ( mbode ) , which includes body mass index , airflow obstruction , dyspnea , and exercise capacity ; the ado , composed of age , dyspnea , and airflow obstruction ; and the modified dose ( mdose ) , comprising dyspnea , airflow obstruction , smoking status , and exacerbation frequency.resultsamong these indices , the frequency distribution of the mbode index was the most widely and normally distributed . univariate cox proportional hazards analyses revealed that the scores on three indices were significantly predictive of 5-year mortality of copd ( p < 0.001 ) . the scores on the mbode and ado indices were more significantly predictive of mortality than forced expiratory volume in 1 second , the medical research council dyspnea score , and the st . george s respiratory questionnaire total score . however , peak oxygen uptake on progressive cycle ergometry was more significantly related to mortality than the scores on the three indices ( p < 0.0001).conclusionthe multidimensional staging systems using the mbode , ado , and mdose indices were significant predictors of mortality in copd patients , although exercise capacity had a more significant relationship with mortality than those indices . the mbode index was superior to the others for its discriminative property . further discussion of the definition of disease severity is necessary to promote concrete multidimensional staging systems as a new disease severity index in guidelines for the management of copd .

the rich transport behavior in complex systems is an important research topic in statistical physics @xcite . consider the mean square of a physical quantity ( such as position ) as a function of time @xmath0 for an ensemble of particles . for normal diffusion , this mean quantity is proportional to @xmath0 ; whereas for anomalous diffusion , the mean quantity goes like @xmath1 ( @xmath2 ) , with subdiffusion referring to cases of @xmath3 and superdiffusion referring to cases of @xmath4 . in the classical domain , known examples of anomalous diffusion include brownian motion and heat conduction . in the quantum domain , wavepacket spreading in a periodic potential leads to ballistic transport in the mean square position ( @xmath5 ) . by contrast , wavepacket spreading in a quasi - periodic potential often induces subdiffusion or superdiffusion @xcite . the special class of diffusion with @xmath6 , which may be termed as `` superballistic transport '' , is however not as well - studied as other cases of anomalous transport behavior . in the classical domain , superballistic transport was observed for brownian particles @xcite . in the quantum case , a time - dependent random potential was demonstrated to cause superballistic transport using paraxial optical setting @xcite . more related to this work , earlier superballistic transport was found in the dynamics of wavepacket spreading in a tight - binding lattice junction @xcite . remarkably , such type of quantum superballistic transport was recently experimentally realized by use of optical wave packets in a designed hybrid photonic lattice setup @xcite . the main objective of this work is to use a relatively simple model system to better understand the difference and connection between quantum and classical superballistic transport in purely hamiltonian systems . to our knowledge , the model studied in this work represents the only dynamical model that can possess superballistic transport in both quantum and classical hamiltonian dynamics . this will shed more light on various mechanisms of superballistic transport as well as on the general issue of quantum dynamics in classically chaotic systems . further studies regarding the subtle correspondence between quantum and classical superballistic transport can be also motivated . specifically , we consider a relativistic variant @xcite of the well - known kicked - rotor ( kr ) model @xcite and reveal the quantum and classical superballistic transport dynamics in the momentum space . such a system can be also regarded as a periodically driven dirac system , and it should be of some experimental interest due to recent advances in the quantum simulation of dirac - like particles . in the massless case in which the kinetic energy of a relativistic particle is a linear function of momentum , the relativistic kr variant was known as the `` maryland model '' , first investigated by grempel _ et . @xcite , berry @xcite and simon @xcite to analytically understand the issue of anderson localization . for a dirac particle with a nonzero mass , the bare dispersion relation now lies between linear and quadratic : for low momentum values the dispersion is almost quadratic and for very high momentum values the dispersion approaches a linear function . in effect , this realizes a situation , now in the momentum space , in which two ( momentum ) sublattices with different dispersion relations ( and hence different nature of on - site potential ) are connected as a junction @xcite . as shown later , this indeed induces superballistic transport in both the classical and quantum dynamics . interestingly , the detailed mechanism in the former is still markedly different from that in the latter . in particular , in the classical case , it is necessary to break the global kam curves in the classical phase space because the superballistic transport roots in an unusually complicated escape from a phase space regime of random motion to a simple ballistic structure . by contrast , in the quantum case , breaking global kam curves are not essential for quantum superballistic transport to occur thanks to quantum tunneling through the kam curves . this paper is organized as follows . in sec . ii , we introduce our model and discuss its relation with the well - known maryland model . in sec . iii we study quantum superballistic dynamics , followed by a parallel study of classical superballistic transport and the associated classical phase space structure in sec . section v concludes this work . consider a one - dimensional relativistic quantum kr @xcite : @xmath7 where all the variables are scaled and hence in dimensionless units . here @xmath8 and @xmath9 are pauli matrices , @xmath10 represents the speed of light , @xmath11 represents the static mass energy , @xmath12 represents the strength of a delta - kicking field that is @xmath13-periodic in the coordinate @xmath14 ( @xmath15 is an integer ) and unity - periodic in time , @xmath16 , where @xmath17 is a dimensionless effective planck constant . in the case of a vanishing @xmath11 , the hamiltonian can be decoupled into two independent hamiltonians , each associated with one eigen - spinor of @xmath8 . they are nothing but the so - called maryland model @xcite : @xmath18 early studies on this massless relativistic kr @xcite investigated the consequences of rational or irrational values of @xmath19 . indeed , by mapping the maryland model onto a one - dimensional anderson model , it becomes clear that @xmath20 with an irrational @xmath19 should display anderson localization in the momentum space @xcite , whereas @xmath20 with a rational @xmath21 ( @xmath22 and @xmath23 integers ) should show ballistic transport , so long as the parameter @xmath15 in the kicking potential is an integer multiple of @xmath23 @xcite . this condition is called a resonance condition . when this resonance condition is not fulfilled , i.e. , @xmath24 , it can be shown that the time - evolving wavefunction of the system ( with rational @xmath19 ) repeats itself after every @xmath23 kicking periods , so neither anderson localization nor ballistic transport occurs . roughly speaking , what is known in the standard quantum kr @xcite applies also here , concerning the importance of the arithmetic nature of @xmath19 for the dynamics of the maryland model , as well as the ballistic transport due to quantum resonances therein . though in this work we will focus on cases with a nonzero @xmath11 , the above - mentioned results for the maryland model do guide us when it comes to choose interesting parameter regimes . for example , we shall pay special attention to whether or not @xmath19 is a rational value , and if the kicking potential is resonant or not . as it turns out , the quantum dynamics is most interesting in cases with rational @xmath19 and under the resonance condition . since our model is a periodically driven system , we write down its floquet operator in the @xmath14-representation , i.e. , the propagator associated with one - period time evolution : @xmath25 without loss of generality we set @xmath26 throughout , keeping in mind that if @xmath27 , we may just absorb it into other parameters @xmath11 and @xmath12 . due to this choice , with periodic boundary conditions in @xmath14 , momentum can only take integer values . the above expression of the floquet operator is a product of two exponentials . the second factor @xmath28 $ ] comes from the kicking field , giving rise to the hopping between different momentum states ( different sites in the momentum space ) , whereas the first factor @xmath29 $ ] is responsible for generating momentum - dependent on - site phases . in particular , the state at a site @xmath30 can be decomposed into local spin - up and spin - down components , each component acquiring a phase factor @xmath31 : @xmath32.\ ] ] clearly then , it is the periodic and alternative on - site phase accumulation @xmath31 and the hopping @xmath33 $ ] that determine the quantum dynamics . this motivates us to also consider a slightly different floquet operator @xmath34 : @xmath35 for this spinless floquet operator , the two spin components are decoupled . nevertheless , it still contains the same local phase accumulation given by @xmath31 and the same hopping term as in our original model described by @xmath36 . as seen later , it does possess the essential properties of @xmath36 and as such our physical analysis can be reduced . more importantly , the system @xmath34 does not have the spin degree of freedom , so its classical limit can be constructed with ease , with the classical hamiltonian given by @xmath37 indeed , the so - called classical relativistic kr map studied in the literature @xcite was based on such a spinless classical hamiltonian . in the following , we study the quantum dynamics using both @xmath36 and @xmath34 , and the classical dynamics based on @xmath38 . the dynamics of a quantum relativistic kr was previously studied in ref . @xcite for relatively short time scales . by extending to a longer time scale and choosing the right parameter regime , quantum superballistic transport is found for driven systems described by @xmath36 as well as its spinless version @xmath34 . to justify our choices of the system parameters we first examine cases with an irrational value of @xmath19 . in the maryland model , an irrational @xmath19 leads to localization in the momentum space . so it is interesting to first investigate how a nonzero mass @xmath11 changes this picture . when @xmath19 is irrational , the previously defined phase factor @xmath31 in eq . is in general a pseudo - random function of the momentum site . this is different from the maryland model , in which @xmath39 and the corresponding @xmath31 would then reduce to a quasi - periodic function of momentum sites . in the light of the mapping from a kr system to the anderson localization model @xcite , this seems to indicate that a non - zero @xmath11 favors dynamical localization in the momentum space . note also that , for very large values of @xmath30 , the relative importance of the @xmath11 term in @xmath31 will diminish , and then effectively a maryland model will be recovered and dynamical localization is still guaranteed @xcite . thus , in the entire momentum space , a non - zero @xmath11 is expected to strengthen the dynamical localization , thus also wiping out any possibility of anomalous diffusion or superballistic transport . results of our numerical simulations presented in fig . [ fig : m_irra ] support our above view . for both the full floquet operator @xmath36 and its spinless version @xmath34 , it is seen from fig . [ fig : m_irra ] that the momentum spread @xmath40 decreases as @xmath11 increases , i.e. , a larger @xmath11 enhances dynamical localization . as a function of number of kicks ( time @xmath0 ) . solid lines represent results generated by the floquet operator @xmath36 defined in eq . ( [ floquetr ] ) , with the initial state given by spin - up and a gaussian wavepacket @xmath41 . the dot - dashed lines represents the results generated by a spinless floquet operator @xmath34 defined in eq . ( [ floquetrn ] ) , with the initial wavepacket given by the gaussian @xmath41 . in both cases , @xmath42 , irrational @xmath43 , @xmath44 , @xmath45 and @xmath11 takes values of 0 , 6 and 10 . ( results of @xmath36 and @xmath34 with @xmath39 are identical . ) @xmath40 is seen to be strongly localized in all the examined examples . here and in all other figures , all plotted quantities are in dimensionless units . ] with the same set of system parameters , the mean momentum spread under the evolution of the floquet operator @xmath36 is similar to that under the evolution of its spinless version @xmath34 . this confirms that the common on - site phase accumulation function @xmath31 has captured the main features of dynamical localization . it is also interesting to comment on the differences between these two cases . that is , @xmath40 associated with @xmath36 is always larger than that associated with @xmath34 . as such , the spin degree of freedom is seen to slightly weaken dynamical localization . this is somewhat expected . indeed , the spin degree of freedom introduces two channels for the dynamics and a multi - channel anderson model does increase the localization length @xcite . we note in passing that the spin degree of freedom can even cause anderson transition in two - dimensional disordered systems @xcite . certainly , as @xmath11 increases , this spin effect should decrease because it becomes more costly in energy for the two spin channels to interact . finally , we mention the benchmark result in fig . [ fig : m_irra ] for the @xmath39 case that represents the maryland model . the perfect revival of @xmath40 was predicted by berry @xcite . using our system parameters depicted in the caption of fig . [ fig : m_irra ] , berry s result gives @xmath46 and our simulation agrees with this . as we already discussed in the previous subsection , for large momentum values , the effect of a nonzero mass term @xmath11 will diminish and effectively the maryland model will re - emerge . so if we were not to choose an on - resonance potential , then in regimes of large momentum quantum revivals should occur for rational @xmath19 , which is not of interest here . in addition , we also observed that for an off - resonance kicking potential and for rational @xmath19 , a non - zero @xmath11 further suppresses the already bounded momentum spread . with these understandings , it is clear that we should step into the interesting situation where @xmath21 is rational and the kicking potential @xmath47 is on resonance , i.e , @xmath48 . for convenience we choose @xmath49 . reference @xcite computationally investigated exactly the same situation , but it was argued therein that the phase factor @xmath31 as a pseudo - random function of momentum should suffice to localize the momentum spread . as we show below , both qualitatively and quantitatively , this claim is correct only for low momentum values , and overall a much richer transport behavior can be found . let us start with the maryland model for which @xmath39 . then the momentum space is translational invariant with period @xmath23 . as such , states will in general spread ballistically ( the off - resonance case is an exception ) . in our case , @xmath50 and within each period , the on - site phase @xmath31 acquired by the system becomes a quasi - random function of @xmath30 , thus dynamical anderson localization or suppression of momentum spread is expected . however , as momentum increases , the nonzero @xmath51 term in @xmath52\right)$ ] becomes less important as compared with @xmath53 . for very large momentum , the @xmath51 term represents a very weak perturbation and hence the dynamics should resemble that of the maryland model . the above qualitative analysis makes it clear that the overall dynamics depends on many factors . on a sublattice representing low momentum values from @xmath54 to @xmath55 , dynamical localization takes place and the system is effectively in a disordered regime . on a sublattice representing higher momentum values , ballistic transport is expected and the system is effectively in a periodic regime . whether or not a state is localized or delocalized now depends on where it is initially located , and on the size of the disordered regime as compared with the localization length . for example , if an initial state is localized at the center of the disordered regime and if the localization length is much shorter than the disordered region , then the system may be trapped there for an extremely long time . on the other hand , if the initial state is already located close to the high - momentum sublattice ( closeness is with respect to the localization length ) , then as the kicking field induces population transfer between the disordered sublattice and the periodic sublattice , the system will be quickly delocalized . in this sense , our model , through its natural dispersion relation , realizes a lattice junction analogous to that considered in refs . certainly , in our model here there is no sharp transition between the two qualitatively different sublattices , but the critical momentum value is expected to scale with @xmath56 . vs time , for @xmath39 , @xmath57 , @xmath58 , @xmath59 and @xmath60 ( from top to bottom ) . results with @xmath57 , @xmath58 , @xmath59 are for the spinless floquet operator @xmath34 defined in eq . ( [ floquetrn ] ) . for @xmath60 , results for both @xmath36 ( the one fitted by a power - law with @xmath61 ) and @xmath34 ( the most localized case ) are plotted . ( result with @xmath39 is applicable to both @xmath36 and @xmath34 . ) other system parameters are the same as in fig . [ fig : m_irra ] , except for @xmath62 . the two dashed straight lines represent a power - law fitting @xmath63 ( for a certain time window ) with @xmath61 or @xmath64 , indicating quantum superballistic transport with an exponent close to @xmath65 . ] representative results from our numerical experiments are presented in fig . [ fig : m_ra_log ] . there it is seen that as @xmath11 increases , an initial state localized at the center of the disordered sublattice will be trapped for a longer period . this is consistent with our understanding that an increasing @xmath11 leads to a longer disordered sublattice as well as a shorter localization length . other numerical results ( not shown ) show that the values of @xmath19 , the kicking strength @xmath12 , and the potential parameter @xmath15 can all affect the duration during which an initial state is trapped in the disordered regime . two of the computational examples shown in fig . [ fig : m_ra_log ] also display quantum superballistic transport , i.e. @xmath63 with @xmath6 , where @xmath0 is the number of kicks . this can now be explained using the idea from ref . in particular , assuming that the length of the disordered momentum sublattice is larger than the corresponding localization length , then the disordered regime serves as a source to provide slow probability leakage into a periodic regime at an almost constant rate . then we have @xmath66 here @xmath67 is the probability leaking rate from the disordered sublattice to the periodic sublattice , @xmath68 represents the contribution from the disordered regime , which is almost constant and can be neglected . @xmath69 represents the probability of the initial state already placed in the periodic regime , which is 0 due to our choice of the initial state located at the center of the disordered regime . @xmath70 characterizes the ballistic transport coefficient , which depends on many system parameters . if we approximate @xmath67 by a constant @xmath71 , then from eq . we approximately have @xmath72 as reflected by the two cases shown in fig . [ fig : m_ra_log ] , namely , the case of @xmath60 for the full floquet operator @xmath36 and the case of @xmath59 for the spinless floquet operator @xmath34 defined in eq . ( [ floquetrn ] ) , @xmath63 , with @xmath73 or @xmath74 , for a very long time scale and covering a huge range of @xmath40 ( note the logarithmic scales used in the plot ) . these two superballistic exponents are very close to @xmath65 , in agreement with the above theory . for the same two cases , we have set @xmath75 and record the probabilities inside @xmath76 $ ] as a function of time . this probability indeed decreases linearly with time . this further confirms the physical mechanism behind the quantum superballistic transport seen here . the case shown in fig . [ fig : m_ra_log ] with @xmath57 displays ballistic transport as the case of @xmath39 . this is so because for a small value of @xmath11 the initial state quickly experiences ballistic transport on the clean sublattice . for the intermediate case @xmath58 , the momentum spread does not show any clear power - law dependence . in this transitional case , the localization length and the size of disordered lattice are comparable and hence the leakage from the disordered sublattice to the periodic sublattice occurs no longer at an almost constant rate . we stress that the shown cases represent but a few examples . many similar results of quantum superballistic transport are obtained for both the full floquet operator @xmath36 involving two spin channels and for the spinless floquet operator @xmath34 . though the quantum superballistic transport here is explained in the same manner as in ref . @xcite , we stress that the effective two - sublattice configuration is not artificially designed . rather , it emerges as a natural consequence of the relativistic dispersion relation with a nonzero mass . in this subsection we will study the classical relativistic kr described by the hamiltonian in eq . . to that end , it is necessary to examine the phase space structure , which can be generated from the relativistic standard map @xcite . in particular , the states right after the @xmath77-th and @xmath78-st kick are connected by the map @xmath79 in the quantum case , either an irrational @xmath19 or a non - resonant kicking potential causes localization . considering quantum - classical correspondence , this suggests bounded ( i.e. , localized in momentum ) invariant curves in the phase space . results in fig . [ fig : phasespaceallcases](b)-(d ) support this view . defined in eq . ( [ spinlessh ] ) , for four different situations , namely , ( a ) rational @xmath19 and on - resonance kicking potential , ( b ) irrational @xmath19 with off - resonance kicking potential , ( c ) irrational @xmath19 with an almost on - resonance kicking potential ; and ( d ) irrational @xmath19 with an off - resonance kicking potential . @xmath59 and @xmath80 . the phase space invariant curves are seen to be unbounded in momentum in panel ( a ) , but bounded in panels ( b)-(d ) . ] to understand the phase space structure , we first recall the maryland model @xcite , which can approximately describe the dynamics for sufficiently large momentum values . that is , if @xmath30 is large , then we again neglect the @xmath11 term in the hamiltonian . then the mapping in eq . ( after dropping the @xmath11 term ) reduces to the mapping associated with the maryland model . for the maryland model , the following equations hold for either an irrational @xmath19 or a non - resonant kicking potential : @xmath81\right)\\ & \quad + p_0 , \end{split}\ ] ] where as introduced before , @xmath82 . clearly then , for an irrational @xmath19 , the term @xmath83 can densely cover the entire @xmath14 domain @xmath84 $ ] . as such , as @xmath77 increases , the values of @xmath85 fill a complete sine curve in the phase space . on the other hand , if @xmath19 is rational , @xmath86 becomes a fraction under the assumed off - resonance condition , then @xmath87 can only take discrete points in @xmath84 $ ] such that @xmath88 also takes a few isolated values @xcite . these observations for the maryland model can be used to directly explain the panel ( d ) in fig . [ fig : phasespaceallcases ] . for panel ( b ) where @xmath19 is rational but the kicking potential is off resonance , a nonzero @xmath11 also causes the dynamics to densely fill the entire @xmath14 domain , which constitutes an interesting difference from the maryland model . however , as expected , after the same number of iterations , regimes with low momentum values can generate a complete phase invariant curve faster , and regimes with high momentum values may still have holes to be filled in . as to panel ( c ) where the product of @xmath89 is close to an integer , the oscillation amplitude in momentum get larger as the factor @xmath90 in the map in eq . ( [ p_theta_bounded ] ) can be a large number . putting all these cases together , it is seen that in the three situations represented by panels ( b)-(d ) of fig . [ fig : phasespaceallcases ] , kam invariant curves localized in momentum are the main characteristic of the classical phase space . so now we are left with the last situation in which @xmath19 is rational and the kicking potential is on resonance . the associated phase space structure is presented in panel ( a ) of fig . [ fig : phasespaceallcases ] and in fig . [ fig : kam_detail ] . the phase space structure is remarkably complicated and interesting . to investigate this in detail , we divide the phase space into four regimes , namely regimes i , ii , iii and iv for increasing absolute values of momentum . let us take one example to look into the special phase space structure . as seen in fig . [ fig : kam_detail ] for @xmath44 , @xmath59 , the four regimes have qualitatively different behavior . in regime i where @xmath30 is small , local kam curves dominate . as @xmath30 increases , the feature of the phase space become chaotic in regime ii . this is followed by global kam curves in regime iii . these global kam curves are localized in momentum and bound the chaotic sea seen in regime ii . finally , in regime iv for quite large momentum , ballistic curves , which become more and more parallel to the momentum axis , are seen . these curves are called ballistic curves because once a trajectory lands on such a structure its momentum variance will evolve ballistically . . here system parameters are given by @xmath44 , @xmath59 , @xmath62 , and @xmath45 . panel ( a ) depicts regimes with large momentum values , and panel ( b ) depicts regimes with low momentum values . curves in regime i are local kam curves , kam curves in regime iii are global curves and hence localize momentum . the black dots regime in ii are generated by a single initial condition and indicate a chaotic sea . curves in regimes iv that are almost parallel to the momentum axis are ballistic structures . ] the four regimes identified above may not always appear together . their presence and borders are determined by @xmath11 and @xmath12 . to shed some light on this , one may consider @xmath38 , in the two opposite limits , i.e. , `` non - relativistic '' @xmath91 limit and `` ultra - relativistic '' limit @xmath92 . in the first limit , @xmath38 becomes @xmath93 and in the second limit , @xmath38 assumes @xmath94 regimes i and ii can be understood via @xmath95 , while regime iv can be well understood by @xmath96 . in particular , @xmath95 is the conventional kicked rotor , which makes the regular - to - chaotic transition as @xmath12 increases @xcite . @xmath96 is much similar to the hamiltonian of the maryland model , which is known to produce ballistic trajectories in the momentum space @xcite . indeed , it can be shown that the asymptotic ( in the large @xmath30 limit ) form of the ballistic trajectories are described by @xmath97 , and they are hence completely parallel to the momentum axis . as is found from our computational studies , an increase in @xmath12 may destroy the kam curves in regimes i and iii , and then turns them to a ( possibly transient ) chaotic sea as well . an increase in @xmath11 will generate more kam curves in the phase space . the complexity of the phase space perhaps deserves more careful studies . for our purpose here , we emphasize that for a sufficiently large @xmath12 , the phase space is mainly composed of a seemingly chaotic sea and ballistic trajectories . it is however challenging to identify a clear boundary between trajectories eventually landing on the ballistic structure and those always doing random motion . to appreciate this complexity , in fig . [ fig : phasesinglepoint ] we illustrate that once global curves are all broken , how an individual trajectory might eventually land on the ballistic structure after transient , but a long period of , chaotic " motion . the whole process is like the following : after the system has wandered in the transient chaotic sea [ see panel ( b ) ] for a long time , the system finally reaches @xmath98 and keeps moving to the left . then it reaches @xmath99 and continues to move towards the left . it then passes the central transient chaotic sea " . later the system has a chance to arrive @xmath100 , followed by @xmath101 . the system eventually reach a ballistic curve @xmath102 and then keeps moving up in the momentum space . in brief , it takes 3 stages for a trajectory launched from the regime illustrated in panel ( b ) of fig . [ fig : phasesinglepoint ] to finally turn to ballistic motion . first , it wanders highly randomly in a transient chaotic sea . second , it moves alternatively along some smooth curves [ such as those shown in panel ( a ) and panel ( c ) in fig . [ fig : phasesinglepoint ] ] , between which the system returns to the transient chaotic sea , but with the overall tendency towards curves of large momentum values . lastly , the system evolves on a simple ballistic structure . . the total evolution time is @xmath103 , by which time this trajectory becomes clearly ballistic . the whole process is remarkably complicated . panels ( a ) ( b ) and ( c ) zoom in some small portions of the shown phase space , with the momentum values in the middle-@xmath14 regime seen to be highly localized . green dash - dotted arrow shows the moving direction of the trajectory along the curves " traced by the trajectory . these curves shown here emerges after @xmath104 , and similar curves developed in earlier time with smaller @xmath30 values . note that these curves are not kam invariant curves as the system will eventually leave them . we define the motion along these curves as transient chaotic motion " . ] in our simulations , we always choose @xmath105 phase space points randomly sampled from the following gaussian distribution @xmath106 note that this gaussian distribution is analogous to the initial gaussian wavepacket we used in our quantum dynamics calculations . we then evolve this ensemble of classical trajectories according to the relativistic kr map described by eq . and examine the ensemble averaged @xmath40 as a function of @xmath0 , i.e. , the number of iterations . interestingly , the time dependence of @xmath40 is rich , and if we fit @xmath40 by the power - law @xmath107 for appropriate time windows , the exponent @xmath108 can be larger than 2 . in fact , sometimes @xmath108 can be even larger than three or even four . some examples are shown in fig . [ fig : ksm10 ] . in one case , the superballistic transport exponent is found to be as large as @xmath109 , for a time window from @xmath110 to @xmath111 . on the one hand this confirms that the classical dynamics may display superballistic transport , on the other hand it is necessary to better understand the underlying mechanism . by exploring many parameter choices , it is found that breaking the global kam curves with an increasing ratio @xmath112 is a necessary condition . this is already a clear difference from quantum superballistic transport . for example , for the results shown in fig . 2 , @xmath113 , @xmath45 , @xmath59 , quantum superballistic transport occurs already for @xmath44 , but in the classical case shown in fig . [ fig : ksm10 ] , superballistic transport is observed only when @xmath12 exceeds 1.4 . thus , in the quantum case , a global kam invariant curve does not forbid the population leakage from the classically chaotic regime to the ballistic regime , an indication of quantum tunneling . vs time ( the number of kicks ) . the initial conditions are sampled from a gaussian distribution described by eq . with @xmath114 and @xmath115 , so that the initial phase space distribution is analogous to the quantum initial state used in fig . [ fig : m_ra_log ] . here @xmath113 , @xmath45 , @xmath59 , and from top to bottom , @xmath116 , and @xmath117 . note that with other system parameters being the same , quantum superballistic transport already occurs for @xmath44 ( see fig . [ fig : m_ra_log ] ) . here the classical superballistic transport emerges until @xmath12 reaches 1.4 . ] to further understand the numerical results , we find it necessary to also account for normal diffusion as the trajectories seek to land on ballistic trajectories from the chaotic sea . the associated normal diffusion rate is assumed to be @xmath118 . we further assume that the leakage rate from the chaotic sea to the ballistic structure is given by @xmath67 . then analogous to eq . ( [ psquare ] ) , we expect to have @xmath119 where @xmath120 , with @xmath121 being the fraction of trajectories confined in some local stable islands in regime i and @xmath122 being their average momentum spread ; @xmath123 , with @xmath124 representing the fraction of trajectories undergoing normal diffusion , with @xmath118 being the associated diffusion constant ; @xmath125 is the faction of trajectories initially placed on ballistic structures , with @xmath70 being the diffusion coefficient . note that , unlike in the quantum case , at this point we do not first assume a constant probability leakage rate because , as seen below , the leakage involves different behavior at different time windows , and so @xmath67 can be rather complicated . indeed , as seen from fig . [ fig : phasesinglepoint ] , once the global kam curves are destroyed , the escape from a ( transient ) chaotic sea to a ballistic structure is extremely complicated : the boundary between them is hard to identify and different initial conditions sampled from an initial gaussian ensemble may need drastically different times to reach a ballistic structure . the coexistence of normal diffusion , ballistic transport , and the potentially complicated leakage rate @xmath67 makes the time dependence of @xmath126 even more interesting than the quantum case . let us roughly define a regime @xmath127 $ ] in the phase space , where trajectories are not doing ballistic motion . in connection with our observations made from fig . [ fig : phasesinglepoint ] , we choose @xmath128 . let @xmath129 be the occupation probability of this regime and @xmath130 be the occupation probability on ballistic structures . then @xmath131 . @xmath129 is plotted in fig . [ fig : ksm10probleak_combine ] on either linear or logarithmic scales , for different time windows , for the value @xmath132 already studied in fig . [ fig : ksm10 ] . the right inset of fig . [ fig : ksm10probleak_combine ] indicates that initially most trajectories are trapped in the regime @xmath127 $ ] , until @xmath133 . then @xmath129 starts to decrease more appreciably , with a time dependence not easy to fit [ see the first part of the curve in panel ( c ) ] . after @xmath134 kicks however , the relation between @xmath129 and @xmath0 becomes much more evident , i.e. @xmath135 , which indicates an exponential decay . the emergence of an exponential decay suggests that the ensemble has reached a certain steady configuration , as the escape probability now becomes proportional to the occupation probability itself . as also shown by the bottom inset and by the main figure of fig . [ fig : ksm10probleak_combine ] , the coefficient @xmath71 slightly changes with time . expanding such an exponential decay to the first order , this escape would amount to an almost constant leakage rate of jumping onto phase space ballistic structures . as a result , one would naively expect , like our analysis in the quantum part , a superballistic transport case with @xmath65 . this prediction is certainly oversimplified as compared with our actual results shown in fig . [ fig : ksm10 ] . vs time , where @xmath136 defined in the text represents the occupation probability in a non - ballistic regime . for the two insets ( a ) and ( b ) , @xmath129 vs time is plotted for two early stages , where it can be seen that initially most trajectories are trapped in the initial non - ballistic regime for @xmath137 . then @xmath129 starts to decrease appreciably in a nonlinear fashion . the inset ( c ) shows that the time dependence of @xmath138 is highly nonlinear before @xmath139 . however , after @xmath140 , @xmath138 and @xmath0 display a linear relation . the system parameters are the same as the case of @xmath132 in fig . [ fig : ksm10 ] . ] to better digest the results shown in fig . [ fig : ksm10 ] , we again focus on the case @xmath132 in connection with the time dependence of @xmath129 in fig . [ fig : ksm10probleak_combine ] . in the very beginning , @xmath129 remains almost a constant until @xmath141 kicks , so for this time period @xmath67 is essentially zero . therefore initially only the first three terms in eq . are non - zero , suggesting that the diffusion exponent of @xmath40 should be less than two . this explains the actual numerical result during the early stage . the plotted curve in fig . [ fig : ksm10 ] at early times also has an increasing slope . this can be explained as follows . during the early stage , we have @xmath142 . when @xmath143 , the @xmath144 term starts to dominate so @xmath40 is close to normal diffusion . similarly , when @xmath145 , the @xmath146 term exceeds the first two , so we have a behavior close to ballistic transport for a quite long period until @xmath134 . on the other hand , from fig . [ fig : ksm10probleak_combine ] , it is observed that since as early as @xmath133 , @xmath67 is already non - zero . so the leakage to the ballistic regime is building up long before an exponential leakage is observed at @xmath147 . this early - stage leakage to the ballistic regime starts to affect the time dependence of @xmath40 only until @xmath148 . we conjecture that this is the reason why in fig . [ fig : ksm10 ] a simple relation @xmath149 is not observed . in addition , the lack of such a simple superballistic behavior with @xmath65 is also consistent with the apparent nonlinear time dependence shown in panel ( c ) of fig . [ fig : ksm10probleak_combine ] before @xmath139 . $ ] vs @xmath150 , an analysis motivated by a reset of the start time at @xmath139 ( see the text for the details ) . the result here mainly displays a normal diffusion stage and a superballistic transport stage with an exponent close to @xmath65 . the computational example presented here is the same one in fig . [ fig : ksm10probleak_combine ] with @xmath132 . the dashes lines represent power - law fitting . ] to confirm our qualitative analysis above , we now redefine the start time as the point when an exponential decay of @xmath129 can be clearly identified . again using the computational example shown in fig . [ fig : ksm10probleak_combine ] , we now use @xmath140 as the start time to count change in the momentum spread . that is , we now examine @xmath151 $ ] . because at @xmath152 , the population inside the regime @xmath127 $ ] is about 0.88 , we have @xmath153 $ ] . then we have @xmath154 & \approx 0.88\ d_0 e^{-\gamma ( t - t_2 ) } ( t - t_2 ) \\ & \quad + 0.12\ a ( t - t_2)^2 \\ & \quad + a \int^t_{t_2 } { r(t ' ) ( t - t')^2 { \mathrm{d}}t ' } , \end{split}\ ] ] where the first term account for the normal diffusion as the trajectories diffuse from a chaotic sea to eventually land on a ballistic structure , the second term describes the ballistic transport for those trajectories already outside the regime @xmath127 $ ] at the start time @xmath152 , and the last term describes the impact on the transport dynamics due to the population leakage from the regime @xmath127 $ ] , with @xmath155 \approx 0.88\ \gamma.\end{aligned}\ ] ] equation ( [ psquare2_ciii ] ) thus suggests that once we reset the start time at @xmath152 , there should be a normal diffusion stage , a transition stage due to the second term , followed by a superballistic transport period , i.e. , @xmath156 \sim ( t - t_2)^3 $ ] . in fig . [ fig : k1_4m10_truncated ] we present a numerical log - log plot of @xmath151 $ ] vs @xmath150 , in very good agreement with our analysis . as a final note , the classical superballistic transport shown in fig . [ fig : k1_4m10_truncated ] with the diffusion exponent @xmath157 lasts very long , but this behavior can not last forever . in the end , almost all trajectories from the initial ensemble will end up on ballistic structures and then purely ballistic transport will take over . returning to an early study @xcite of the classical relativistic kr under the resonance condition , we have to disagree with some of their statements ; from our results we conclude that classical superballistic transport was not observed there because the investigation time scale there was too short . in this work , we show that both quantum and classical superballistic transport can occur in a simple periodically driven system , namely , a relativistic kicked - rotor system with a nonzero mass term . to our knowledge , this appealing scenario has not been discussed before . compared with previous lattice - junction models for quantum superballistic transport , the superballistic transport in our model occurs in momentum space as a consequence of a natural divide imposed by the relativistic dispersion : regions with low momentum effectively have a quadratic ( bare ) dispersion relation ( hence effectively a quasi - random on - site potential ) and regions of high momentum effectively have a linear ( bare ) dispersion relation ( hence effectively a quasiperiodic potential ) . remarkably , though found in the same dynamical system , the quantum superballistic and classical superballistic transport we have analyzed are observed in much different parameter regimes . indeed , in the quantum case , the mechanism lies in the leakage of the quantum state from a regime of dynamical localization to a regime of ballistic transport . this leakage can occur even when the underlying classical limit has global kam invariant curves separating the two regimes . in the classical case , it is necessary to break the global kam curves first to allow for leakage from a chaotic sea to ballistic trajectories . as a side result , we find that this kind of leakage in the classical dynamics is unexpectedly complicated and further studies can be motivated . for example , strictly speaking , the random patterns shown in the panel ( b ) of fig . [ fig : phasesinglepoint ] do not represent chaos ( chaos is defined as a positive lyapunov exponent in the asymptotic long - time limit , but this trajectory will eventually become ballistic and hence has a zero lyapunov exponent ) . the detailed characteristics of this type of irregular trajectory eventually becoming a regular ballistic one deserve more attention . the issue of quantum - classical correspondence concerning this type of trajectories is also of considerable interest for future studies . the classical relativistic kicked rotor model may be realized by considering relativistic electrons moving in the field generated by a special electrostatic wavepacket @xcite . on the quantum side , a spinless version of the relativistic kicked rotor may be also realized by considering a kicked tight - binding lattice whose on - site potential can be determined by the relativistic dispersion relation @xcite . however , due to the large time scales involved , a direct observation of our numerical results reported here is unlikely . as such it should be interesting enough to explore the system more to identify other signatures of superballistic transport at shorter time scales . 99 b. d. hughes , random walks and random environments ( clarendon press , oxford , 1995 ) . y. he , s. burov , r. metzler , and e. barkai , phys . * 101 * , 058101 ( 2008 ) . r. metzler and j. klafter , phys . rep . * 339 * , 1 ( 2000 ) . j. p. bouchaud and a. georges , phys * 195 * , 127 ( 1990 ) . b. i. henry , t.a.m . langlands , and p. straka , in complex physical , biophysical and econophysical systems , world scientific lecture notes in complex systems , edited by r. l. dewar and f. detering ( world scientific , singapore , 2010 ) , vol . 9 . j. wang , i. guarneri , g. casati , and j. b. gong , * 107 * , 234104 ( 2011 ) ; h. l. wang , j. wang , i. guarneri , g. casati , and j. b. gong , * 88 * , 052919 ( 2013 ) . s. abe and h. hiramoto , phys . a * 36 * , 5349 ( 1987 ) ; h. hiramoto and s. abe , j. phys . * 57 * , 230 ( 1988 ) ; * 57 * , 1365 ( 1988 ) . f. pichon , phys . . lett . * 76 * , 4372 ( 1996 ) . r. ketzmerick , k. kruse , s. kraut , and t. geisel , phys . lett . * 79 * , 1959 ( 1997 ) . k. l and j .- d . bao , phys . e * 76 * , 061119 ( 2007 ) . p. siegle , i. goychuk , p. talkner , and p. hnggi , phys . e * 81 * , 011136 ( 2010 ) ; p. siegle , i. goychuk , and p. hnggi , phys . lett . * 105 * , 100602 ( 2010 ) ; p. siegle , i. goychuk , and p. hnggi , europhys . lett . * 93 * , 20002 ( 2011 ) . l. levi , y. krivolapov , s. fishman and m. segev , nat . * 8 * , 912 ( 2012 ) . l. hufnagel , r. ketzmerick , t. kottos , and t. geisel , phys . e 64 , 012301 ( 2001 ) . z. j. zhang , p. q. tong , j. b. gong , and b. w. li , , 070603 ( 2012 ) . s. sttzer , t. kottos , a. tnnermann , s. nolte , d. n. christodoulides , and a. szameit , opt . lett . * 38 * , 4675 ( 2013 ) . a. a. chernikov , t. tl , g. vattay , and g. m. zaslavsky , phys . a * 40 * , 4072 ( 1989 ) . d. u. matrasulov , g. m. milibaeva , u. r. salomov , and b. sundaram , phys . e * 72 * , 016213 ( 2005 ) . g. casati and b. v. chirikov , quantum chaos : between order and disorder ( cambridge university press , new york , 1995 ) . d. r. grempel , s. fishman , and r. e. prange , phys . 49 * , 833 ( 1982 ) . r. e. prange , d. r. grempel , and s. fishman , phys . b * 29 * , 6500 ( 1982 ) . m. v. berry , physica d * 10 * , 369 ( 1984 ) . b. simon , annals of physics * 159 * , 157 ( 1985 ) . y. nomura , y. h. ichikawa , and w. horton , phys . a * 45 * , 1103 ( 1992 ) . s. fishman , d. r. grempel , and r. e. prange , phys . * 49 * , 509 ( 1982 ) . p. mello , p. pereyra , and n. kumar , ann . phys . * 181 * , 290 ( 1988 ) . s. n. evangelou and t. ziman , journal of physics c : solid state physics * 20 * , l235 ( 1987 ) . d. n. sheng and z. y. weng , phys . b * 54 * , r11070 ( 1996 ) . j. b. gong and j. wang , phys . e * 76 * , 036217 ( 2007 ) . t. boness , s. bose , and t. s. monteiro , phys . * 96 * , 187201 ( 2006 ) .

as an unusual type of anomalous diffusion behavior , superballistic transport is not well known but has been experimentally simulated recently . quantum superballistic transport models to date are mainly based on connected sublattices which are constructed to have different properties . in this work , we show that both quantum and classical superballistic transport in the momentum space can occur in a simple periodically driven hamiltonian system , namely , a relativistic kicked - rotor system with a nonzero mass term . the nonzero mass term essentially realizes a junction - like scenario : regimes with low or high momentum values have different dispersion relations and hence different transport properties . it is further shown that the quantum and classical superballistic transport should occur under much different choices of the system parameters . the results are of interest to studies of anomalous transport , quantum and classical chaos , and the issue of quantum - classical correspondence .

SECTION 1. FINDINGS. Congress finds as follows: (1) Each year, in every corner of the Nation, the 850,000 first responders of Emergency Medical Services answer more than 30,000,000 calls to serve 22,000,000 patients in need of life saving care and comfort at a moment's notice and without reservation. With little regard for their own safety and in the face of all hazards the men and women of Emergency Medical Services respond across the spectrum of incidents from a single person's medical emergency to the naturally occurring or man- made disasters, including terrorist attacks that threaten the entire Nation. This commitment to others, at a moment's notice and despite risk, exemplifies the finest traditions of American spirit. (2) As an element of the Nation's homeland defense strategy, Emergency Medical Services stands on the ``Nation's first line of defense in the prevention and mitigation of risk from terrorist attacks, man-made incidents, and natural disasters.''. The men and women of Emergency Medical Services, alongside those in Law Enforcement and the Fire Service, serving in both the public and private sectors as career and volunteer emergency medical service providers, are a critical element of the Nation's homeland and national security efforts and provide for the domestic tranquility of its citizens. (3) All too often the risks associated with the critical role of Emergency Medical Services results in an unacceptable rate of injury and fatality to these responders. Statistics compiled by the United States Department of Labor and the National Highway Safety Administration indicate that emergency medical services providers die in the line of duty at a rate more than twice the national average for all occupational fatalities and during their careers experience an injury rate of virtually 100 percent. (4) We as a Nation have historically and continually relied on the selfless and ultimate sacrifices made by the men and women of this great country, their families, and loved ones in order to maintain the domestic tranquility, safety, and security of this Nation. The men and women of Emergency Medical Services continue to serve in this finest tradition, in the face of unacceptable sacrifice, risk and danger in service to the Nation and its citizens. (5) The scope of responsibility assumed by the men and women of the Emergency Medical Services is broad and unique and their sacrifice and commitment in service to our Nation are deserving of a commemorative work that recognizes such. SEC. 2. AUTHORIZATION TO ESTABLISH COMMEMORATIVE WORK. (a) In General.--The National Emergency Medical Services Memorial Foundation may establish a commemorative work on Federal land in the District of Columbia and its environs to commemorate the commitment and service represented by emergency medical services. (b) Compliance With Standards for Commemorative Works.--The establishment of the commemorative work under this section shall be in accordance with chapter 89 of title 40, United States Code (commonly known as the ``Commemorative Works Act''). (c) Prohibition on the Use of Federal Funds.-- (1) In general.--Federal funds may not be used to pay any expense of the establishment of the commemorative work under this section. (2) Responsibility of national emergency medical services memorial foundation.--The National Emergency Medical Services Memorial Foundation shall be solely responsible for acceptance of contributions for, and payment of the expenses of, the establishment of the commemorative work under this section. (d) Deposit of Excess Funds.-- (1) In general.--If upon payment of all expenses for the establishment of the memorial (including the maintenance and preservation amount required by section 8906(b)(1) of title 40, United States Code), there remains a balance of funds received for the establishment of the commemorative work, the Association shall transmit the amount of the balance to the Secretary of the Interior for deposit in the account provided for in section 8906(b)(3) of title 40, United States Code. (2) On expiration of authority.--If upon expiration of the authority for the commemorative work under section 8903(e) of title 40, United States Code, there remains a balance of funds received for the establishment of the commemorative work, the Association shall transmit the amount of the balance to a separate account with the National Park Foundation for memorials, to be available to the Secretary of the Interior or Administrator (as appropriate) following the process provided in section 8906(b)(4) of title 40, United States Code, for accounts established under 8906(b)(2) or (3) of title 40, United States Code.

Authorizes the National Emergency Medical Services Memorial Foundation to establish a commemorative work on federal land in the District of Columbia and its environs to commemorate the commitment and service represented by emergency medical services. Prohibits the use of federal funds to pay any expense of the establishment of such work. Makes the Foundation solely responsible for acceptance of contributions for, and payment of the expenses of, the establishment of such work. Provides for the deposit of excess funds received for such work into a National Park Foundation account.

during the last two decades one could observe a remarkable progress in laser technology . since the invention of the cpa technique @xcite in 1985 , the maximum laser intensity has been increased by seven orders of magnitude reaching nowadays the value @xmath6w/@xmath5 @xcite . moreover , the announced new generation of @xmath3 pw laser facilities like eli beamlines , which is now under construction in prague , czech republic @xcite , or vulcan in uk @xcite , will provide intensity above @xmath4w/@xmath5 . therefore physics in the presence of such ultra - strong fields is now coming upon a focus of attention . one of the most striking effects in this area is electron - positron pair creation from vacuum @xcite . however , according to recent calculations @xcite , spontaneous pair creation from vacuum would require an optical laser of the power above @xmath7 pw , still far from the experimental possibilities of the nearest future . another important example of ultra - strong field physics phenomena are quantum electrodynamical ( qed ) cascades @xcite . in the present paper we consider cascades seeded by electrons , that are initially at rest at the focus of intense laser field . they are accelerated by laser field emitting hard photons , which in turn create further electron - positron pairs . the created electrons and positrons are again accelerated by the field thus emitting hard photons , which again create new pairs and so on . such an avalanche - like process finishes by escape of the particles from the focal region . observation of qed cascade production in a laboratory is important for both fundamental physics and testing the qed principles . however , numerical simulations performed in the previous works @xcite for some particular models of laser pulses have indicated that the threshold intensity required for cascade development would be of the order or above @xmath8w/@xmath5 . in the latter case this may still exceed the capabilities of such facilities as e.g. the eli beamlines . our goal is to optimize the experimental setup , in particular the field distribution at the focus , thus suggesting configuration that decreases the threshold intensity required for qed cascade production . consider the qed field strength parameter @xmath0 @xcite @xmath9 where @xmath10 and @xmath11 are the electron mass and charge , @xmath12 is the particle energy and @xmath13 is the component of the lorentz force per unit charge @xmath14 $ ] transverse with respect to the particle velocity @xmath15 . in the framework of a locally constant field approximation @xcite the parameter ( [ chi ] ) evolves in between the hard photon emission and pair creation events according to the classical equations of motion and its instant value defines the probabilities of these processes @xcite @xmath16 where @xmath17 and @xmath18 are the probabilities of pair creation and hard photon emission , respectively , @xmath19 is the energy of radiating electron or pair creating photon and @xmath20 is the fine structure constant . since @xmath21 is less than @xmath22 of a radiating electron and pair creation is exponentially suppressed at @xmath23 , we have to find such a field configuration that provides the most rapid growth of @xmath0 . back to @xmath0 . ] then we calculate numerically the threshold intensity for qed cascade development in such an optimal field configuration . assume that a seeding particle is placed initially at rest at the focus of the laser field . in order to optimize field configuration for cascade production , we derive first a formula for the time dependence @xmath24 near the focus , i.e. in a time range @xmath1 , where @xmath2 is the field carrier frequency . in this case the electric and magnetic fields can be expanded into taylor series @xmath25 with respect to time and coordinates @xmath26 . since a standing wave composed of two identical counterpropagating laser beams produces cascades more efficiently than a single beam of the same total power @xcite , we assume in advance that the electric field at the center of the focal region reaches maximum and the magnetic field vanishes . besides , in what follows we assume that the laser field is so strong that particles become ultrarelativistic soon after start of acceleration , @xmath27 , where @xmath28 is the acceleration time , but still remains much weaker than the qed critical field , @xmath29v / cm . let us find the particle momentum satisfying the equation of motion @xmath30 in the form @xmath31 , where @xmath32 . for @xmath33 onwards . ] the solution of equations of motion , accurate to the zeroth order in @xmath34 , reads @xmath35 using expressions for the fields within the first order in @xmath34 , @xmath36 , @xmath37 , where @xmath38 we can solve the first order equation of motion @xmath39 , where @xmath40,\ ] ] and obtain for the particle velocity @xmath41 , @xmath42 since the magnitude of the transverse component of the lorenz force is equal to @xmath43|=ef_\bot^{(1 ) } t/2 $ ] , where @xmath44 is the component of ( [ f ] ) transverse to the initial electric field @xmath45 , we arrive at the formula @xmath46 the result ( [ chipar ] ) is in agreement with special cases of rotating purely electric field and a standing plane wave obtained previously in refs . @xcite and @xcite . hence , in order to optimize field configuration for cascade production we must increase the coefficient at @xmath47 in the formula ( [ chipar ] ) as much as possible . ( color online ) . allocation of @xmath48 tightly focused beams colliding in a plane . ] a method for reducing the total threshold power for spontaneous pair creation from vacuum via multibeam technology was suggested in ref . @xcite , where it was clearly demonstrated how the key parameter of that problem , the electric field strength in the focus , can be increased considerably by splitting a laser beam into several pairs of linearly polarized colliding beams of the same total power . however , in our case of cascade production linear polarization is expected to be unfavorable @xcite . therefore we modify that scheme not restricting polarization of individual beams a priory . let us consider an even number @xmath49 of focused beams propagating in @xmath50 plane at angles @xmath51 with the @xmath52 axis ( see fig . [ 8beams ] ) and optimize their polarization for cascade production . for not too strong focused beams their field near the focus can be well approximated by plane waves @xmath53 here @xmath54 , @xmath55 are the individual polarization vectors , which we do not require in advance to be normalized , and @xmath56 are the unit vectors directed along the focal axis of the beams . in case all the beams are focused weakly , the power of each of the beams can be estimated as @xmath57 , where @xmath58 is a geometric factor depending on the beam shape , @xmath59 is the focal cross section area of the beam . the same kind of formula remains true for a tight focusing case as well , but the geometric factor in such a case is modified ( see below ) . below , we prefer to fix the total power @xmath60 of the beams , in terms of which @xmath61.\ ] ] due to transversality of the plane waves ( [ aplane ] ) , all the terms containing space derivatives in ( [ deb ] ) vanish within this approximation , so that @xmath62 . substituting @xmath63 into ( [ chipar ] ) and taking into account ( [ a0 ] ) , for @xmath64 colliding beams we obtain @xmath65 where the factor @xmath66},\quad \boldsymbol{\epsilon}_{1,2}=\sum\limits_{j=1}^n\boldsymbol{\epsilon}^j_{1,2}\ ] ] totally determines dependence of @xmath0 on the number of beams and their polarization . evidently , in order to maximize the expression ( [ f ] ) all the vectors @xmath67 should be parallel each other . since the @xmath50-plane had been chosen as the plane of beam propagation , we assume thus that @xmath67 are all directed along the @xmath68-axis , @xmath69 , where @xmath70 is the corresponding versor . also , since the electric field in the beam is transverse to the wave propagation direction @xmath71 , or just @xmath72 , for all @xmath73 . ] , we can assume that @xmath74 . due to the symmetry of the problem the polarization vector of the total electric field can lie in any plane parallel to @xmath68-axis . let it be the @xmath75- plane . then @xmath76 where , to clarify further manipulations , in the last representation we have introduced four formal @xmath64-vectors @xmath77 , @xmath78 , @xmath79 and @xmath80 , the latter with all @xmath64 components equal to @xmath81 . now it follows from the chain of inequalities @xmath82 that @xmath83 reaches its maximum value when @xmath84 , @xmath85 and @xmath86 . for @xmath87 these conditions are equivalent to @xmath88 in particular , @xmath89 i.e. the optimal polarization of the total field is elliptical with the semi - major to semi - minor axis ratio equal to @xmath90 . the polarization vectors of the individual beams in such an optimal case are @xmath91 in case @xmath92 the factor @xmath93 does not appear in denominator of eq . ( [ exy ] ) , hence the optimal polarization is circular , @xmath94 . .[tab1]power and intensity thresholds for generation of qed cascades in configurations with @xmath64 colliding beams ( @xmath95 , @xmath96 ) . [ cols="^,^,^,^,^",options="header " , ] ( color online ) number of electrons in a cascade versus time for optimal ( solid ) and circular ( dashed ) polarization of the total field ( @xmath97 , @xmath96 , @xmath98ev , @xmath99w , @xmath100 is the laser period ) . ] ( color online ) . the mean value of @xmath0 for electrons located at a distance smaller than @xmath101 from the origin . the parameters are the same as in fig . [ nt ] . ] the threshold power for cascade generation can be found by numerical simulations . in fact , qed cascades do not possess a natural sharp threshold , so that we define it formally as creation of just a single pair on average by each seed electron during passage of laser pulses through the focus . as a more realistic model we use a model of the focused laser beam suggested in refs . @xcite @xmath102\\ & \times\left(\boldsymbol{\epsilon}^j-\frac{\omega^2{([\boldsymbol{\epsilon}^j\times\hat{\mathbf{n}}^j]\cdot \mathbf{r}^j_\bot)[\hat{\mathbf{n}}^j\times \mathbf{r}^j_\bot]}}{\xi+i\omega r^j_\parallel}\right ) \end{split}\ ] ] which is an approximate solution of maxwell equations near the focal region if @xmath103 . here , @xmath104 and @xmath105 are the components of the radius vector , parallel and perpendicular to @xmath106 . the parameter @xmath107 , where @xmath108 is the diffraction length , controls the degree of beam focusing ; @xmath71 , @xmath109 and @xmath110 are all defined after eq . ( [ aplane ] ) ; @xmath111 is the total power of all colliding beams . it follows from ( [ chin ] ) that for given total power , the geometric factor @xmath112 ( i.e. , focusing ) should be maximized . note that in modern laser facilities the beam can be focused so tightly , that a half of the beam power is passing through a circle of the wavelength diameter in the focal plane @xcite . computing numerically the power of a beam over a circle of the diameter @xmath113 around the focus , we obtain , that the condition @xmath114\right|_{r^j_\parallel=0}=\frac{p_j}{2},\ ] ] where @xmath115 is the power of the @xmath116-th beam , is satisfied if the focusing parameter @xmath117 . here @xmath118 and @xmath119 are the polar coordinates in the plane @xmath120 . it is also worth taking into account that there exist bounds for a number of beams that can be allocated concurrently in a plane without overlapping @xcite . at far distance from the focal region the field of each of the beams is almost confined to a cone with aperture @xmath121 , which is simply related to our focusing parameter @xmath122 . indeed , for @xmath123 the energy of the field is proportional to @xmath124 . therefore we can estimate the aperture by @xmath125 . for @xmath96 , @xmath126 , hence the number of beams that can be allocated without overlapping in the @xmath50-plane must be less than @xmath3 . hence , for @xmath96 the maximal even number of beams is @xmath127 as in fig . [ 8beams ] . for numerical simulations we have used two independent codes . the first one @xcite is a realization of monte - carlo ( mc ) algorythm , in which we assume that electrons and positrons are moving classically between the emission events , which are implemented by the corresponding event generators similar to refs . the second one is a more general 3d particle - in - cell - monte - carlo ( pic - mc ) code for simulation of laser - plasma interactions with quantum radiation effects @xcite . actually , in our problem the electron - positron plasma remains dilute and the results obtained with both codes are in good agreement . in this paper we present the results obtained with the first ( pure mc ) code . since our field model ( [ afed ] ) corresponds to a field unbounded in time , we take into account finiteness of pulse duration artificially by limiting the simulation time . the simulation time was chosen to be @xmath128 laser periods @xmath100 as is typical for modern laser facilities @xcite . in simulations , the seed particles were represented by a bunch of @xmath129 electrons placed initially at rest near the center @xmath130 of the focus . the laser carrier wavelength was taken to be @xmath131 m , which corresponded to laser photon energy @xmath81ev and the focusing parameter was chosen as @xmath96 for the reasons discussed above . the resulting power and intensity thresholds obtained by numerical simulation of qed cascade development in the cases of @xmath92 , @xmath132 , @xmath133 , and @xmath127 beams with optimal polarization ( [ optpol ] ) , colliding in a plane are presented in table [ tab1 ] . one can observe that both the laser power and intensity required for cascade production decrease significantly due to a multibeam setup . cascade dynamics for the cases of optimal elliptic polarization and circular polarization of the total field for the case of @xmath48 beams is displayed on fig . the figure clearly demonstrates the advantage of the suggested optimal polarization . besides , it is clear from fig . [ nt ] that in the case of optimal polarization cascade development is splitted into two stages , which differ by the slope of the curve . at the first stage the seeding particles are accelerated by the field , create pairs and escape the focal region . almost all created particles also leave the focal region with a speed close to the speed of light , see fig . [ positrons ] . still , a small fraction of slow particles remains in the focal region being accelerated by the field . at time @xmath134 the mean value of the parameter @xmath0 for particles at the focus becomes large enough to initiate the second stage of cascade development , see fig . we have demonstrated that qed cascades can arise in laser - target interaction for laser power below @xmath3 pw and intensity below @xmath8w/@xmath5 . this is realizable with a multibeam setup , i.e. splitting of the original laser pulses into several pairs of colliding beam . in order to determine how to arrange the beams , we have derived an analytical formula for growth of the parameter @xmath24 , which determines possibility of qed cascade generation . this allowed us to identify the optimal beam polarization with the most rapid growth of @xmath24 at the focus . for such an optimal configuration of @xmath64 beams and fixed total laser power , @xmath0 is proportional to @xmath64 . however , for our extreme choice of the focusing parameter , which corresponds to the state - of - the - art experimental capabilities , the maximal number of beams that can be brought together in a planar configuration of fig . [ 8beams ] is @xmath48 . thus we have next computed the qed cascade thresholds for the particular case of @xmath48 optimally polarized beams . according to our simulations , in this case the threshold total power @xmath135 pw and the threshold intensity @xmath136w/@xmath5 . such parameters had been previously announced as being achievable with the new generation of laser facilities @xcite in the nearest future . this research was supported by the government of the russian federation ( project no . 14.b25.31.0008 ) , the russian fund for basic research ( grants 13 - 02 - 00372 and 13 - 02 - 00886 ) and the rf president program for support of young russian scientists and leading research schools ( grant nsh-4829.2014.2 ) . aam acknowledges partial support from the dynasty foundation . 99 d. strickland , g. mourou , optics communications * 55 * , 447 ( 1985 ) . bahk , p. rousseau , t. a. planchon , v. chvykov , g. kalintchenko , a. maksimchuk , g. a. mourou , and v. yanovsky , opt . letters * 29 * , 2837 ( 2004 ) ; v. yanovsky , v. chvykov , g. kalinchenko , p. rousseau , t. planchon , t. matsuoka , a. maksimchuk , j. nees , g. cheriaux , g. mourou , and k. krushelnick , opt . express * 16 * , 2109 ( 2008 ) . the+vulcan+10+petawatt+project/14684.aspx f. sauter , z. phys . * 69 * , 742 ( 1931 ) ; _ ibid _ * 73 * , 547 ( 1932 ) ; j. schwinger , phys . rev . * 82 * , 664 ( 1951 ) . a. i. nikishov , sov . jetp * 30 * , 660 ( 1970 ) . n. b. narozhny , s. s. bulanov , v. d. mur and v. s. popov , phys . lett . a * 330 * , 1 ( 2004 ) ; s. s. bulanov , n. b. narozhny , v. d. mur and v. s. popov , jetp * 102 * , 9 ( 2006 ) . a. m. fedotov , laser physics * 19 * , 214 ( 2009 ) . s. s. bulanov , v. d. mur , n. b. narozhny , j. nees , and v. s. popov , phys . lett . * 104 * , 220404 ( 2010 ) . a. r. bell and j. g. kirk , phys . * 101 * , 200403 ( 2008 ) ; j. g. kirk , a. r. bell and i. arka , plasma phys . fusion * 51 * , 085008 ( 2009 ) . a. m. fedotov , n. b. narozhny , g. mourou , and g. korn , phys . * 105 * , 080402 ( 2010 ) . n. v. elkina , a. m. fedotov , i. yu . kostyukov , m. v. legkov , n. b. narozhny , e. n. nerush , and h. ruhl , phys . stab * 14 * , 054401 ( 2011 ) . e. n. nerush , i. yu . kostyukov , a. m. fedotov , n. b. narozhny , n. v. elkina , and h. ruhl , phys . lett . * 106 * , 035001 ( 2011 ) . r. duclous , j. g. kirk , and a. r. bell , plasma phys . fusion * 53 * , 015009 ( 2011 ) . v. f. bashmakov , e. n. nerush , i. yu . kostyukov , a. m. fedotov and n. b. narozhny , phys . plasmas * 21 * , 013105 ( 2014 ) . a. a. mironov , n. b. narozhny , and a. m. fedotov , phys . a * 378 * , 3254 ( 2014 ) . d. l. burke , r. c. field , g. horton - smith , j. e. spencer , d. walz , s. c. berridge , w. m. bugg , k. shmakov , a. w. weidemann , c. bula , k. t. mcdonald , e. j. prebys , c. bamber , s. j. boege , t. koffas , t. kotseroglou , a. c. melissinos , d. d. meyerhofer , d. a. reis , and w. ragg , phys . * 79 * , 1626 ( 1997 ) ; c. bamber , s. j. boege , t. koffas , t. kotseroglou , a. c. melissinos , d. d. meyerhofer , d. a. reis , w. ragg , c. bula , k. t. mcdonald , e. j. prebys , d. l. burke , r. c. field , g. horton - smith , j. e. spencer , d. walz , s. c. berridge , w. m. bugg , k. shmakov , and a. w. weidemann , phys . rev . d * 60 * 092004 ( 1999 ) . a. i. nikishov , v. i. ritus , sov . jetp * 19 * , 529 ( 1964 ) ; _ ibid _ * 25 * , 1135 ( 1967 ) ; v. n. baier , v. m. katkov , phys . 25a * , 492 ( 1967 ) . s. s. bulanov , t. zh . esirkepov , a. g. r. thomas , j. k. koga , and s. v. bulanov phys . 105 * , 220407 ( 2010 ) . n. b. narozhny , and m. s. fofanov , jetp * 90 * , 753 ( 2000 ) ; phys . a * 295 * , 87 ( 2002 ) . i. gonoskov , a. aiello , s. heugel and g. leuchs , phys . a * 86 * , 053836 ( 2012 ) . e. n. nerush et al . plasmas * 21 * , 013109 ( 2014 ) .

qed cascades in intense electromagnetic field can occur if the dynamical quantum parameter @xmath0 of a seed electron , which in compton units coincides with the electron proper acceleration , attains the order of unity . we derive general expression for @xmath0 of an initially slow electron in an arbitrary electromagnetic field for a time range @xmath1 , where @xmath2 is the field carrier frequency . using this formula , we consider a special field configuration of multiple colliding focused laser beams and optimize it to provide cascade development at laser power below @xmath3 pw and intensity of the order of @xmath4w/@xmath5 . such parameters of the beams will be obtained with a new generation of laser facilities , particularly the eli beamlines , in the coming years .

SECTION 1. SHORT TITLE; TABLE OF CONTENTS. (a) Short Title.--This Act may be cited as the ``Cabin Fee Act of 2010''. (b) Table of Contents.--The table of contents for this Act is as follows: Sec. 1. Short title; table of contents. Sec. 2. Definitions. Sec. 3. Cabin user fees. Sec. 4. Cabin transfer fees. Sec. 5. Right of appeal and judicial review. Sec. 6. Consistency with other law and rights. Sec. 7. Regulations. SEC. 2. DEFINITIONS. In this Act: (1) Authorization.--The terms ``authorized'' and ``authorization'' refer to the issuance of a special use permit for the use and occupancy of National Forest System land derived from the public domain by a cabin owner under the Recreation Residence Program. (2) Cabin.--The term ``cabin'' means a privately built and owned recreation residence and related improvements on National Forest System land derived from the public domain that is authorized for private use and occupancy and may be sold or transferred between private parties. (3) Cabin owner.--The term ``cabin owner'' means-- (A) a person authorized by the Secretary to use and to occupy a cabin on National Forest System land derived from the public domain; and (B) a trust or an heir or assigns of such a person. (4) Cabin transfer fee.--The term ``cabin transfer fee'' means a fee paid to the United States upon the transfer of a cabin between private parties for money or other consideration that also includes issuance of a new permit. (5) Cabin user fee.--The term ``cabin user fee'' means an annual fee paid to the United States by a cabin owner pursuant to an authorization for the use and occupancy of a cabin on National Forest System land derived from the public domain. (6) Current appraisal cycle.--The term ``current appraisal cycle'' means the completion of Forest Service review and acceptance of initial typical lot appraisals or second appraisals if ordered by cabin owners and approved by the Forest Service. (7) Current cabin user fee.--The term ``current cabin user fee'' means the most recent cabin user fee, which results from an annual adjustment to the prior cabin user fee under section 3(d). (8) Lot.--The term ``lot'' means a parcel of National Forest System land derived from the public domain on which a person is authorized to build, use, occupy, and maintain a cabin. (9) National forest system land.--The term ``National Forest System land'' is limited to National Forest System land derived from the public domain. (10) Recreation residence program.--The term ``Recreation Residence Program'' means the Recreation Residence Program established pursuant to the last paragraph under the heading ``Forest service'' in the Act of March 4, 1915 (38 Stat. 1101, chapter 144; 16 U.S.C. 497). (11) Secretary.--The term ``Secretary'' means the Secretary of Agriculture, acting through the Chief of the Forest Service. (12) Typical lot.--The term ``typical lot'' means a cabin lot, or group of cabin lots, in a tract that is selected for use in an appraisal as being representative of, and that has similar value characteristics as, other lots or groups of lots within the tract. SEC. 3. CABIN USER FEES. (a) Payment of Cabin User Fees.--A cabin user fee shall be paid annually by the cabin owner. (b) Initial Cabin User Fees.-- (1) Establishment.--The Secretary shall establish initial cabin user fees in the manner required by this subsection. (2) Assignment to value tiers.--Upon completion of the current appraisal cycle, as required by paragraph (4), the Secretary shall assign each permitted lot on National Forest System land to 1 of 9 tiers based on the following: (A) All appraised lot values shall be adjusted, or normalized, for price changes from its date of value according to the national NAHB/Wells Fargo Housing Opportunity Index prior to tier assignment. (B) Second appraisal values approved by the Forest Service shall supersede initial lot appraisal values for the normalization and ranking process under subparagraph (A). (C) The tiers shall be established, on a national basis, according to relative lot value, with lots having the lowest adjusted appraised value assigned to Tier 1 and lots having the highest adjusted appraised value assigned to Tier 9. (D) The number of lots (by percentage) assigned to each tier is specified in the table contained in paragraph (3). (E) Data from incomplete appraisals may not be used to establish the fee tiers. (F) Until assigned to a tier, permitted cabin lots, including lots with incomplete appraisals, are assigned an interim fee of $4,500 or their current annual fee, indexed in accordance with subsection (d), whichever is less. (3) Table of initial cabin user fees.--The initial cabin user fees, based on the assignments made by the Secretary under paragraph (2) are as follows: ------------------------------------------------------------------------ Approximate Percent of Fee Tier Permits Nationally Fee Amount ------------------------------------------------------------------------ Tier 1 not to exceed 8% $500 ------------------------------------------------------------------------ Tier 2 not to exceed 12% $1,000 ------------------------------------------------------------------------ Tier 3 not to exceed 12% $1,500 ------------------------------------------------------------------------ Tier 4 not to exceed 14% $2,000 ------------------------------------------------------------------------ Tier 5 at least 14% $2,500 ------------------------------------------------------------------------ Tier 6 not to exceed 14% $3,000 ------------------------------------------------------------------------ Tier 7 not to exceed 12% $3,500 ------------------------------------------------------------------------ Tier 8 not to exceed 8% $4,000 ------------------------------------------------------------------------ Tier 9 not to exceed 6% $4,500. ------------------------------------------------------------------------ (4) Deadline for completion of current appraisal cycle.-- The Secretary shall complete the current appraisal cycle within three years after the date of the enactment of this Act. (5) Effective date.--The initial cabin user fees required by this subsection shall take effect beginning with the first calendar year beginning after the completion of the current appraisal cycle. (c) Overpayments or Underpayments.--If, upon assignment to a tier under subsection (b), the Secretary determines that the fee charged to a cabin owner during the preceding 3 years resulted in an overpayment or underpayment of the fee due under the tier system totaling more than $500, the fee for the next three years shall be adjusted, if such a fee adjustment is requested by the Secretary or by the affected cabin owner, as necessary to correct the overpayment or underpayment. (d) Annual Adjustments of Cabin User Fee.--The Secretary shall use changes in the Implicit Price Deflator for the Gross Domestic Product published by the Bureau of Economic Analysis of the Department of Commerce, applied on a 5-year rolling average, to determine and apply an annual adjustment to cabin user fees. (e) Effect of Destruction, Substantial Damage, or Loss of Access.-- If a cabin is destroyed or suffers substantial damage amounting to greater than 50 percent of replacement cost, or if access to a cabin is significantly impaired, whether by catastrophic events, natural causes or governmental actions, such that the cabin is rendered unsafe or unable to be occupied as a result, the Secretary shall reduce the cabin user fee for the affected lot to $100 per year. This fee shall be in effect for the remainder of the year in which the destruction occurs and until such time as the cabin may be lawfully reoccupied and normal access has been restored. SEC. 4. CABIN TRANSFER FEES. (a) Payment of Cabin Transfer Fees.--In conjunction with the transfer of ownership of any cabin and the issuance of a new permit, the transferor shall file with the Secretary a sworn statement declaring the amount of money or other value received, if any, for the transfer of the cabin. As a condition of the issuance by the Secretary of a new authorization for the use and occupancy of the cabin, the transferor shall pay, or cause to be paid, to the Secretary a cabin transfer fee in an amount determined as follows: ---------------------------------------------------------------------------------------------------------------- Consideration Received by Transfer Transfer Fee Amount ---------------------------------------------------------------------------------------------------------------- $0 to $250,000 $1,000 ---------------------------------------------------------------------------------------------------------------- $250,000.01 to $500,000.00 $1,000 plus 5% of consideration in excess of $250,000 up to $500,000 ---------------------------------------------------------------------------------------------------------------- $500,000.01 and above $1,000 plus 5% of consideration in excess of $250,000 up to $500,000 plus 10% of consideration in excess of $500,000. ---------------------------------------------------------------------------------------------------------------- (b) Index.--The Secretary shall use changes in the Implicit Price Deflator for the Gross Domestic Product published by the Bureau of Economic Analysis of the Department of Commerce, applied on a 5-year rolling average, to determine and apply an annual adjustment to the cabin transfer fee threshold amounts ($250,000.01 and $500,000.01) set forth in the table contained in subsection (a). SEC. 5. RIGHT OF APPEAL AND JUDICIAL REVIEW. (a) Right of Appeal.--Notwithstanding any action of a cabin owner to exercise rights in accordance with section 6, the Secretary shall by regulation grant the cabin owner the right to an administrative appeal of the determination of a new cabin user fee, fee tier, transfer fee, or whether or not to reduce a cabin user fee under section 3(e). Such appeal shall be pursuant to the appeal process provided under subpart C (Appeal of Decisions Relating to Occupancy and Use of National Forest System Lands) of part 251 of title 36, Code of Federal Regulations (section 251.80 et seq.). (b) Judicial Review.--A cabin owner that contests a final decision of the Secretary under this Act may bring a civil action in United States district court. The venue for actions brought before the United States District Court shall be in the United States Judicial District where the cabin is located or the permit holder resides. Nothing in this Act precludes the parties from seeking mediation. SEC. 6. CONSISTENCY WITH OTHER LAW AND RIGHTS. (a) Consistency With Rights of the United States.--Nothing in this Act limits or restricts any right, title, or interest of the United States in or to any land or resource. (b) Special Rule for Alaska.--In determining a cabin user fee in the State of Alaska, the Secretary shall not establish or impose a cabin user fee or a condition affecting a cabin user fee that is inconsistent with 1303(d) of the Alaska National Interest Lands Conservation Act (16 U.S.C. 3193(d)). SEC. 7. REGULATIONS. The Secretary shall promulgate regulations to carry out this Act not later than December 31, 2012.

Cabin Fee Act of 2010 - Defines: (1) "cabin user fee" as the annual fee paid to the United States by a cabin owner pursuant to an authorization for the use and occupancy of a cabin on National Forest System land derived from the public domain; (2) "cabin owner" as a person authorized to use and occupy a cabin on National Forest System land derived from the public domain or a trust, or an heir or assignee of such a person; and (3) "cabin" as a privately built and owned recreation residence and related improvements on National Forest System land derived from the public domain that is authorized for private use and occupancy and may be sold or transferred between private parties. Requires the payment of an annual "cabin user fee" by a "cabin owner." Directs the Secretary of Agriculture (USDA) to set such fee. Requires a reduction in the cabin use fee to $100 per year if access to a cabin is significantly impaired, whether by catastrophic events, natural causes or governmental actions, such that the cabin is rendered unsafe or unable to be occupied. Requires payment of a "cabin transfer fee" to the United States upon the transfer of a cabin between private parties for money or other consideration.

encephalomeningocele is a congenital malformation characterized by protrusion of meninges and/or brain tissue due to a skull defect . it is one form of neural tube defects as the other two , anencephaly and spina bifida . despite the higher incidence of this congenital defect in this area , little so far , only aflatoxin has been proposed to be a teratogenic agent for this anomaly . indirect evidences from its closely related anomaly , spina bifida , may suggest the role of folate deficiency in encephalomeningocele . however , again , there were no studies on the relationship between maternal folate level and incidence of encephalomeningocele , and some evidences have suggested different underlying mechanisms between these two forms of neural tube defects . here , we report 20 cases of encephaloceles in 19 patients and review their epidemiological , clinical , imaging characteristics , as well as analyze the surgical results . the aims and objectives of the study are to observe and analyze the epidemiological , clinical , imaging characteristics , as well as analyze surgical results of all cases of encephaloceles that were treated at our institute from july 2012 to june 2015 . the aims and objectives of the study are to observe and analyze the epidemiological , clinical , imaging characteristics , as well as analyze surgical results of all cases of encephaloceles that were treated at our institute from july 2012 to june 2015 . a total of 20 cases of encephalocele in 19 patients were analyzed during the study period . patients with encephalocele were evaluated for epidemiological characteristics , clinical features , imaging characteristics , and surgical results . a total of 20 encephaloceles cases in 19 patients were treated during the study period . one patient had a double encephalocele one of which was atretic [ figure 1 ] . clinical photographs and magnetic resonance imaging images of double encephalocele out of the 20 encephaloceles , 12 ( 60% ) were male and 8 ( 40% ) female patients . the youngest was a 1-day old infant while the oldest child presented at 6 years of age ( median = 1 month , mode = 1 month ) [ table 1 ] . adequate antenatal checkup and folic acid supplementation were received by mothers . however , none of them received preconceptional folic acid . occipital encephaloceles accounted for 12 ( 60% ) , occipito - cervical 4 ( 20% ) , parietal 2 ( 10% ) , fronto - nasal 1 ( 5% ) , and fronto - naso - ethmoidal 1 ( 5% ) . one patient had a double encephalocele ( one atretic and other was occipital ) with dermal sinus tract and limited dermal myeloschisis and a split pons . other associations : chiari 3 malformation ( 2 ) , meningomyeloceles ( 4 ) , and syrinx ( 4 ) . three patients presented with ruptured encephalocele [ table 2 ] . all patients underwent magnetic resonance imaging scan of the head with screening of whole spine ( except patients with ruptured encephaloceles ) . on imaging , 2 patients had only meningoceles , 2 were atretic , while the rest had varying content of brain tissue [ figure 2 ] . magnetic resonance imaging images three patients presented with rupture , one of whom succumbed to shock even before surgery . of the other 2 patients , in whom repair of sac was performed , the patient with meningocele improved while the patient with encephalocele succumbed to meningitis and shock . one patient with fronto - naso - ethmoidal encephalocele was managed with combined open and endoscopic approach . the other 17 encephaloceles treated surgically did well with no immediate surgical mortality [ figure 3 ] . shunt was performed in 4 cases due to the development of hydrocephalus . wound site infection and cerebrospinal fluid ( csf ) leak was seen in 4 cases which were conservatively managed with 1 patient requiring re - exploration and repair . the case with fronto - nasal encephalocele developed ocular csf leak which was conservatively managed . pre- and post - operative images of representative cases the follow - up period ranged from 6 months to 3 years . out of the 20 encephaloceles , 12 ( 60% ) were male and 8 ( 40% ) female patients . the youngest was a 1-day old infant while the oldest child presented at 6 years of age ( median = 1 month , mode = 1 month ) [ table 1 ] . adequate antenatal checkup and folic acid supplementation were received by mothers . however , none of them received preconceptional folic acid . occipital encephaloceles accounted for 12 ( 60% ) , occipito - cervical 4 ( 20% ) , parietal 2 ( 10% ) , fronto - nasal 1 ( 5% ) , and fronto - naso - ethmoidal 1 ( 5% ) . one patient had a double encephalocele ( one atretic and other was occipital ) with dermal sinus tract and limited dermal myeloschisis and a split pons . other associations : chiari 3 malformation ( 2 ) , meningomyeloceles ( 4 ) , and syrinx ( 4 ) . all patients underwent magnetic resonance imaging scan of the head with screening of whole spine ( except patients with ruptured encephaloceles ) . on imaging , 2 patients had only meningoceles , 2 were atretic , while the rest had varying content of brain tissue [ figure 2 ] . magnetic resonance imaging images three patients presented with rupture , one of whom succumbed to shock even before surgery . of the other 2 patients , in whom repair of sac was performed , the patient with meningocele improved while the patient with encephalocele succumbed to meningitis and shock . one patient with fronto - naso - ethmoidal encephalocele was managed with combined open and endoscopic approach . the other 17 encephaloceles treated surgically did well with no immediate surgical mortality [ figure 3 ] . shunt was performed in 4 cases due to the development of hydrocephalus . wound site infection and cerebrospinal fluid ( csf ) leak was seen in 4 cases which were conservatively managed with 1 patient requiring re - exploration and repair . the case with fronto - nasal encephalocele developed ocular csf leak which was conservatively managed . pre- and post - operative images of representative cases the follow - up period ranged from 6 months to 3 years . encephaloceles represents a congenital defect of the cranium in which a portion of central nervous system herniates through the defect . occipital encephaloceles can vary from a small swelling to extremely large one . in our series , the contents of the sac vary from small dysplastic diverticulum to a large amount of degenerative brain tissue . the bony defect can vary in size . in one of the interesting case of ruptured meningocele , the defect had almost closed and hence the patient had a good outcome despite presenting with rupture . male predominance was found in our series compared to other series with most children presenting within 1 month . elective surgery provides time for the patients to gain weight and strength and allows the surgeon to select the best technique . most large encephaloceles required urgent surgical treatment to avoid damage to sac . in all the occipital , parietal and nasal encephaloceles there was dysplastic brain tissue which was removed safely . postoperative hydrocephalus should be managed through ventriculoperitoneal ( vp ) shunts as one or two - stage procedures . four of our cases required postoperative vp shunt in addition to the repair of the sac . in one case of fronto - naso - ethmoidal encephalocele , csf leak and wound infection observed in four cases improved on conservative treatment . an interesting result of csf leak through eyes was noted in one of the cases with fronto - nasal encephalocele . early surgical management of encephalocele is not only for cosmetic reasons but also to prevent tethering , rupture , and future neurological deficits . the authors certify that they have obtained all appropriate patient consent forms . in the form the patient(s ) has / have given his / her / their consent for his / her / their images and other clinical information to be reported in the journal . the patients understand that their names and initials will not be published and due efforts will be made to conceal their identity , but anonymity can not be guaranteed . the authors certify that they have obtained all appropriate patient consent forms . in the form the patient(s ) has / have given his / her / their consent for his / her / their images and other clinical information to be reported in the journal . the patients understand that their names and initials will not be published and due efforts will be made to conceal their identity , but anonymity can not be guaranteed .

background : encephalocele is the protrusion of the cranial contents beyond the normal confines of the skull through a defect in the calvarium and is far less common than spinal dysraphism . the exact worldwide frequency is not known.aims and objectives : to determine the epidemiological features , patterns of encephalocele , and its postsurgical results.materials and methods : the study was carried from year july 2012 to june 2015 . patients with encephalocele were evaluated for epidemiological characteristics , clinical features , imaging characteristics , and surgical results.results:20 encephaloceles patients were treated during the study period . out of these 12 ( 60% ) were male and 8 ( 40% ) female . age range was 1 day to 6 years . the most common type of encephalocele was occipital 12 ( 60% ) , occipito - cervical 4 ( 20% ) , parietal 2 ( 10% ) , fronto - nasal 1 ( 5% ) , and fronto - naso - ethmoidal 1 ( 5% ) . one patient had a double encephalocele ( one atretic and other was occipital ) with dermal sinus tract and limited dermal myeloschisis . other associations : chiari 3 malformation ( 2 ) , meningomyeloceles ( 4 ) , and syrinx ( 4 ) . three patients presented with rupture two of whom succumbed to meningitis and shock . seventeen patients treated surgically did well with no immediate surgical mortality ( except a case of chiari 3 malformation who succumbed 6 months postsurgery to unrelated causes ) . shunt was performed in 4 cases.conclusion:the most common type of encephalocele is occipital in our set up . early surgical management of encephalocele is not only for cosmetic reasons but also to prevent tethering , rupture , and future neurological deficits .

successful renal transplantation is depended on a good compromise between sufficient immunosuppression and adequate level of immune competence which avoid acute rejection and maintaining immunity to prevent infection occurrence , respectively . they include immunosuppression , concomitant states such as urinary reflux disease , diabetes , and renal calculi . despite noticeable progress in surgical procedure and immunosuppression after kidney transplantation , urinary tract infection ( uti ) remains as an important problem in these patients . uti is the most frequency infectious complications , which is reported in up to 86% of transplanted cases . it is considered as the most important risk factor for weak graft function , mortality , and morbidity . although infection mortality rate has declined from 50% to 5% within last 20 years ; it remains as a severe complication posttransplantation , in particular since infections have altered epidemiology . it is crucial to use the best microbiological diagnostic causal factors , which ascertain targeted therapy and reduce much use of antimicrobial drugs . the infection rate is different , regarding to environmental , social , and financial properties between countries all over the world ; and different studies report various frequency , bacteria , and risk factors . according to the importance of renal transplantation in iranian patients and few studies about infections in kidney transplant recipients in iran , this study was done to determine epidemiological , clinical , and subclinical characteristics and causative agents and patient - specific risk factors for utis in transplant recipients 1-year posttransplantation in mashhad city . this single - center retrospective study was performed based on medical findings of kidney transplant recipients in montaserie hospital transplant center of mashhad university of medical sciences(mums ) city during 20122014 . patients who underwent kidney transplantation during at least one year before the study , with complete medical records were entered in the present research . following variables were gathered for each patient : transplantation date , gender , recipient age , donor type ( cadaveric or live ) , medical comorbidities , chronic renal failure etiology , infection , the date of infection , and mean serum creatinine levels during infection . native patient 's kidneys were not removed usually , and the graft kidney was set in the right or left side of iliac fossa . recipients who did not live in mashhad and patients with incomplete clinical data or acute rejection after transplantation were excluded from the study . patients received immunosuppressive therapy and antimicrobial prophylactics including prednisolone , cyclosporine , and mycophenolate moftile , statin drug , co - trimoxazole , and ceftriaxone after surgery . uti was defined based on clinical signs such as fever , urgency , dysuria , frequency , and pyuria . the signs were confirmed by positive urine culture ( > 10 cfu / ml ) , microscopic examination , leukocyte esterase stick , and/or nitrate . all data were accurately recorded and analyzed with spss version 18 software ( spss inc . , chicago , il , usa ) . descriptive statistics including frequency , mean , and standard deviation were considered for all variables . the study was approved by the ethics committee of mashhad university of medical sciences ( code : 940940 , date : may 2016 ) . two hundred and forty - seven renal transplant recipients including 146 males and 101 females were entered in this study . their mean age was 34.94 13.89 years ( the youngest one was 6 , and the oldest one was 66 ) . medical comorbidities of kidney recipients were hypertension ( n = 133 ; 53.8% ) , diabetes mellitus ( n = 105 ; 42.5% ) , chronic obstructive pulmonary disease ( n = 2 ; 0.8% ) , hepatitis ( n = 12 ; 4.8% ) , dyslipidemia ( n = 12 ; 4.8% ) , and other disease ( n = 7 ; 2.8% ) . common causes of renal failure were hypertension ( 58 cases ) , diabetes mellitus ( 20 cases ) , polycystic kidney ( 34 cases ) , reflux nephropathy ( 24 cases ) , pyelonephritis ( 2 cases ) , lupus ( 2 cases ) . renal failure occurred in 41 cases due to other chronic disease ; the cause was indeterminate in 66 cases . forty - one patients had one uti , 11 individuals had two utis , and four cases had three utis . univariate analysis demonstrated that solely female gender was an independent risk factor among different assessed parameters ; it was associated with uti risk ( odds ratio=0.689 ; p = 0.001 ) . the utmost frequent isolated microorganisms were escherichia coli , coagulase - negative staphylococcus , and klebsiella spp . demographic features of 247 cases , who underwent kidney transplantation pathogens diagnosed in infectious subject 's in different times after transplantation bacteremia was developed in 13 patients , which it was originated from urinary tract in four cases . nearly , 61.5% of bacteremia occurred during 3 months after transplantation ; however , patients were taking potent antibiotics during the first 3 months , they were taking strong immunosuppressive drugs too . the mean level of serum creatinine was 1.93 1.26 at the detection time of uti . 53 patients ( 15 in uti cases and 38 in non - uti cases ) developed cmv infection . kidney transplantation is the best treatment for patients at the end - stage of renal disease ( esrd ) . number of kidney recipients is estimated more than 1.4 million worldwide , with 8% rising incident rate , annually . indeed , abundant documents reflect general increment of infections in kidney transplant patients over the last decade . this trend is shift from cardiovascular disorders to infectious diseases as the main cause of death ; many reports indicated admission rates enhancement for infections complications during the 1 year posttransplant . it seems that patients who receive allograft transplant are more susceptible to infections compared to general population . there are accumulating evidence which express direct association between posttransplantation extent immunosuppression therapy and infection occurrence risk . it is not due to specific type of drugs while high dosage intake is related to fewer acute rejections and more infections occurrence , such as uti . uti is one of the causes of pyelonephritis , bacteremia , cmv infections , graft loss , and patient survivals rate reduction . it is the frequent kind of infection in kidney allograft recipients with a varied range 6%86% . the significant variation in uti reported rates may be due to local outbreaks , varying resistance incidences , postoperative medical care , center - specific immunosuppressive therapy , hygienic states , and different diagnostic criteria . 22.7% of renal transplant recipients who were entered in this retrospective research developed at least 1 uti episode during the 1 year after transplantation . uti prevalence was lower in our center ; the predominant causative agent was e. coli in this search ; it is compatible with various others studies from worldwide . over half of infection episodes occurred during 3 months posttransplantation when an immunosuppression strategy was intensive in cited period . the last one constitutes 26.7% of all esrd causes , while it estimated to be 14.4% in other iranians studies , 19.9% in saudi arabia and 14% in qatar . in germany expressed that main primary esrd causes were due to urinary tract malformation , glomerular disorders , and renal dysplasia and to a less scale due to metabolic disorders , polycystic kidney disease , and neurogenic bladder . cited calculi disease , hypertensive nephropathy , glomerulonephritis , polycystic kidney disease , and diabetic nephropathy as kidney failure reasons , too . actually , hypertension could be related to kidney dysfunction and is not primary cause of renal failure . while infectious complications are described as important cause of death in kidney transplant patients , utis have not been associated with high mortality rate in any reports ; our results indicated that there were no relations between utis and graft failure . age , female gender , cadaveric donor , and diabetes mellitus are considered as some potential risk factors for uti occurrence in kidney recipients . adamska et al . expressed that age and length of hospital stay are statistically affect bacterial infections occurrence . female kidney transplant patients have a statistically significant higher occurrence of utis versus male allograft recipients in this center ( p < 0.005 ) which was similar to other studies . it seems that shorter urethra and nearness of urethral opening to anus and vagina are causes of this high prevalence in female gender . taminato et al . indicated that deceased kidney recipients are 20% more susceptible to develop infections , while our study results showed no differences between deceased and live donor recipients . it seems that it is due to cold ischemia time reduction and proper organ preservation . bacterial infections are more prevalent among older ones ; it thought that impaired cellular immunity and immunosuppression tolerance are causes of old patients susceptibility to infection ; however , no evidence were not found in this study to approve this matter . uti is responsible for hospitalization after renal transplantation , early creatinine clearance reduction , reoperation risk increment , and early poor renal function . invasive catheters and prophylactic antibiotics intake should be managed to reduce bacterial and fungal infection incidence after transplantation . our results confirmed the previous researches , but a cohort study is suggested to investigate bacterial and fungal infections effects on long - term survival . this study was done on kidney transplant recipients , and we did not work on antimicrobial resistance , we suggest doing similar study on liver and bone marrow recipients in association with antimicrobial resistance evaluation . this work was supported by a grant from mashhad university of medical sciences ( code 940940 ) . this work was supported by a grant from mashhad university of medical sciences ( code 940940 ) . ab , sfsh , zl , akh , mkh , ssh and ese contributed in the conception and design of the work , analysis , drafting and revising the draft , approval of the final version of the manuscript , and agreed for all aspects of the work .

background : one of the main causes of adverse complications following kidney transplantation is urinary tract infection ( uti ) . this study was done to define the incidence rate , clinical profiles , causative microorganisms , and uti risk factors among kidney transplant recipients in mashhad city.materials and methods : in this retrospective study , we perused medical files of 247 kidney recipients who underwent transplant surgery at mashhad university montaserie hospital , during 20122014 . all patients were followed for uti during the 1st year after surgery.results:75 episodes of uti developed by 152 pathogens in 56 ( 22.7% ) of patients during 1-year follow - up . 26.6% of total utis were diagnosed within the 1st month after transplantation . the most frequently isolated uropathogens were escherichia coli ( 55.3% , n = 84 ) . the high rate of candiduria ( 8.5% ) was observed , too.conclusion:uti is known as one of the hospitalization reasons in kidney transplantation recipients . defining appropriate antibiotic prophylaxis against bacterial and fungal agents and early removal of urethral catheter are suggested to decrease posttransplantation complications .

SECTION 1. DEFINITIONS. Section 4131 of the Safe and Drug-Free Schools and Communities Act of 1994 (20 U.S.C. 7141) is amended by adding at the end the following: ``(7) Abuse.--The term `abuse', used with respect to an inhalant, means the intentional breathing of gas or vapors from the inhalant for the purpose of achieving an altered state of consciousness. ``(8) Drug.--The term `drug' includes a substance that is an inhalant, whether or not possession or consumption of the substance is legal. ``(9) Inhalant.--The term `inhalant' means a product that-- ``(A) may be a legal, commonly available product; and ``(B) has a useful purpose but can be abused, such as spray paint, glue, gasoline, correction fluid, furniture polish, a felt tip marker, pressurized whipped cream, an air freshener, butane, or cooking spray. ``(10) Use.--The term `use', used with respect to an inhalant, means abuse of the inhalant.''. SEC. 2. FINDINGS. Section 4002 of the Safe and Drug-Free Schools and Communities Act of 1994 (20 U.S.C. 7102) is amended-- (1) in paragraph (2), by inserting ``, and the abuse of inhalants,'' after ``other drugs''; (2) in paragraph (5), by striking ``and the illegal use of alcohol and drugs'' and inserting ``, the illegal use of alcohol and drugs, and the abuse of inhalants''; (3) in paragraph (7), by striking ``and tobacco'' each place it appears and inserting ``, tobacco, and inhalants''; (4) in paragraph (9), by striking ``and illegal drug use'' and inserting ``, illegal drug use, and inhalant abuse''; and (5) by adding at the end the following: ``(11)(A) The number of children using inhalants has doubled during the 10-year period preceding 1999. Inhalants are the third most abused class of substances by children age 12 through 14 in the United States, behind alcohol and tobacco. One of 5 students in the United States has tried inhalants by the time the student has reached the 8th grade. ``(B) Inhalant vapors react with fatty tissues in the brain, literally dissolving the tissues. A single use of inhalants can cause instant and permanent brain, heart, kidney, liver, and other organ damage. The user of an inhalant can suffer from Sudden Sniffing Death Syndrome, which can cause a user to die the first, tenth, or hundredth time the user uses an inhalant. ``(C) Because inhalants are legal, education on the dangers of inhalant abuse is the most effective method of preventing the abuse of inhalants.''. SEC. 3. PURPOSE. Section 4003 of the Safe and Drug-Free Schools and Communities Act of 1994 (20 U.S.C. 7103) is amended in the matter preceding paragraph (1) by inserting ``and abuse of inhalants'' after ``and drugs''. SEC. 4. GOVERNOR'S PROGRAMS. Section 4114(c)(2) of the Safe and Drug-Free Schools and Communities Act of 1994 (20 U.S.C. 7114(c)(2)) is amended by inserting ``(including inhalant abuse education)'' after ``drug and violence prevention''. SEC. 5. DRUG AND VIOLENCE PREVENTION PROGRAMS. Section 4116 of the Safe and Drug-Free Schools and Communities Act of 1994 (20 U.S.C. 7116) is amended-- (1) in subsection (a)(1)(A), by inserting ``, and the abuse of inhalants,'' after ``illegal drugs''; and (2) in subsection (b)-- (A) in paragraph (1)-- (i) by inserting ``and the abuse of inhalants'' after ``use of illegal drugs''; and (ii) by inserting ``and abuse inhalants'' after ``use illegal drugs''; and (B) in paragraph (2)-- (i) in the matter preceding subparagraph (A), by inserting ``(including age appropriate inhalant abuse prevention programs for all students, from the preschool level through grade 12)'' after ``drug prevention''; and (ii) in subparagraph (C), by inserting ``and inhalant abuse'' after ``drug use''. SEC. 6. FEDERAL ACTIVITIES. Section 4121(a) of the Safe and Drug-Free Schools and Communities Act of 1994 (20 U.S.C. 7131(a)) is amended in the first sentence by striking ``illegal use of drugs'' and inserting ``illegal use of drugs, the abuse of inhalants,''. SEC. 7. MATERIALS. Section 4132(a) of the Safe and Drug-Free Schools and Communities Act of 1994 (20 U.S.C. 7142(a)) is amended by striking ``illegal use of alcohol and other drugs'' and inserting ``illegal use of alcohol and other drugs and the abuse of inhalants''. SEC. 8. QUALITY RATING. Section 4134(b)(1) of the Safe and Drug-Free Schools and Communities Act of 1994 (20 U.S.C. 7144(b)(1)) is amended by inserting ``, and the abuse of inhalants,'' after ``tobacco''.

Amends the Safe and Drug-Free Schools and Communities Act of 1994 to include prevention of the abuse of inhalants under its programs.

SECTION 1. SHORT TITLE; TABLE OF CONTENTS. (a) Short Title.--This Act may be cited as the ``Commission on Natural Catastrophe Risk Management and Insurance Act of 2007''. (b) Table of Contents.--The table of contents for this Act is as follows: Sec. 1. Short title; table of contents. Sec. 2. Findings. Sec. 3. Establishment. Sec. 4. Membership. Sec. 5. Duties of the Commission. Sec. 6. Timing. Sec. 7. Powers of the Commission. Sec. 8. Commission personnel matters. Sec. 9. Termination. Sec. 10. Authorization of appropriations. SEC. 2. FINDINGS. The Congress finds that-- (1) catastrophic hazards, including tornadoes, earthquakes, volcanoes, landslides, tsunamis, flooding, and hurricanes, directly affect hundreds of millions of people each year; (2) during the 1990s, 2,800 natural disasters killed more than 500,000 people and directly affected 1,300,000,000 people worldwide; (3) property damage from natural catastrophes has dramatically increased in recent decades, roughly doubling every seven years--a 14-fold increase over the past 40 years; (4) risk costs have particularly soared in coastal areas, where hurricane frequency and severity has significantly increased, along with home values and building costs; (5) increased risk costs are being reflected in increased catastrophe insurance and reinsurance costs; (6) an inefficient legal and regulatory environment in some States has further exacerbated insurance cost increases, including through ineffective price controls, restrictions on capital movement, sub-optimal solvency regulation, and duplicative or unnecessary regulation; (7) consumers further suffer from temporary rate and availability volatility after major catastrophes while the marketplace adjusts to the losses; (8) government catastrophe mitigation requirements have been sub-optimal, sometimes ineffective, and uncoordinated; (9) some State efforts to reduce insurance prices in catastrophe-prone areas have sometimes reduced long-term availability and competitive affordability of coverage, as well as subsidized excessive development in environmentally sensitive areas at the expense of taxpayers; (9) several proposals have been introduced in the Congress to address the affordability of natural catastrophe insurance, but there is little consensus on the appropriate role of the Federal Government in facilitating the private insurance marketplace while avoiding cross-subsidies; and (10) therefore, an efficient and effective approach to assessing natural catastrophe risk management and insurance is to establish a nonpartisan commission to study the management of natural catastrophe risk, and to require such commission to report to the Congress on its findings before the next hurricane season begins. SEC. 3. ESTABLISHMENT. There is established a nonpartisan Commission on Natural Catastrophe Risk Management and Insurance (in this Act referred to as the ``Commission''). SEC. 4. MEMBERSHIP. (a) Appointment.--The Commission shall be composed of 16 members, of whom-- (1) 2 members shall be appointed by the Majority Leader of the Senate; (2) 2 members shall be appointed by the Minority Leader of the Senate; (3) 2 members shall be appointed by the Speaker of the House of Representatives; (4) 2 members shall be appointed by the Minority Leader of the House of Representatives; (5) 2 members shall be appointed by the Chairman of the Committee on Banking, Housing, and Urban Affairs of the Senate; (6) 2 members shall be appointed by the Ranking Member of the Committee on Banking, Housing, and Urban Affairs of the Senate; (7) 2 members shall be appointed by the Chairman of the Committee on Financial Services of the House of Representatives; and (8) 2 members shall be appointed by the Ranking Member of the Committee on Financial Services of the House of Representatives. (b) Qualification of Members.-- (1) In general.--Members of the Commission shall be appointed under subsection (a) from among persons who-- (A) have expertise in insurance, reinsurance, insurance regulation, policyholder concerns, emergency management, risk management, public finance, financial markets, actuarial analysis, flood mapping and planning, structural engineering, building standards, land use planning, natural catastrophes, meteorology, seismology, environmental issues, or other pertinent qualifications or experience; and (B) are not officers or employees of the United States Government or of any State government. (2) Diversity.--In making appointments to the Commission-- (A) every effort shall be made to ensure that the members are representative of a broad cross section of perspectives within the United States; and (B) each member of Congress described in subsection (a) shall appoint not more than 1 person from any single primary area of expertise described in paragraph (1)(A) of this subsection. (c) Period of Appointment.-- (1) In general.--Each member of the Commission shall be appointed for the duration of the Commission. (2) Vacancies.--A vacancy on the Commission shall not affect its powers, but shall be filled in the same manner as the original appointment. (d) Quorum.-- (1) Majority.--A majority of the members of the Commission shall constitute a quorum, but a lesser number, as determined by the Commission, may hold hearings. (2) Approval actions.--All recommendations and reports of the Commission required by this Act shall be approved only by a two-thirds vote of all of the members of the Commission. (e) Chairperson.--The Commission shall, by majority vote of all of the members, select 1 member to serve as the Chairperson of the Commission (in this Act referred to as the ``Chairperson''). (f) Meetings.--The Commission shall meet at the call of its Chairperson or a majority of the members. SEC. 5. DUTIES OF THE COMMISSION. The Commission shall examine and report to the Congress on the natural catastrophe insurance marketplace, including the extent to which insurance costs and availability are affected by the factors described in section 2, which factors the Federal Government can and should address to increase catastrophe insurance availability and competitiveness, and which actions the Federal Government can undertake to achieve this goal without requiring a long-term cross-subsidy from the taxpayers. In developing its report, the Commission shall consider-- (1) the current condition of, as well as the outlook for, the availability and affordability of insurance and reinsurance for natural catastrophes in all regions of the United States; (2) the current ability of States, communities, and individuals to mitigate their natural catastrophe risks, including the affordability and feasibility of such activities; (3) the impact of Federal and State laws, regulations, and policies (including rate regulation, market access requirements, reinsurance regulations, accounting and tax policies, State residual markets, and State catastrophe funds) on-- (A) the affordability and availability of catastrophe insurance; (B) the ability of the private insurance market to cover losses inflicted by natural catastrophes; (C) the commercial and residential development of high-risk areas; and (D) the costs of natural catastrophes to Federal and State taxpayers; (4) the benefits and costs of-- (A) a national, regional, or other pooling mechanism designed to provide adequate insurance coverage and increased underwriting capacity to insurers and reinsurers, including private-public partnerships to increase insurance capacity in constrained markets, including proposed Federal natural catastrophe insurance programs (specifically addressing the costs to taxpayers, tax equity considerations, and the record of other government insurance programs, particularly with regard to charging actuarially sound prices); (B) improving Federal and State tax policy to allow insurers or individuals to set aside catastrophe reserves; (C) directing existing Federal agencies to begin selling catastrophe insurance to individuals; (D) creating a consortium of Federal and State officials to facilitate state catastrophe bonds and reinsurance purchasing as well as providing temporary Federal disaster loans to the States for insurance purposes; (E) expanding the Liability Risk Retention Act of 1986 to allow businesses to pool together to buy insurance and set up their own insurance funds; (F) providing temporary Federal assistance to low- income individual homeowners whose catastrophe insurance rates have increased beyond a certain level after a major disaster, with the possibility that the assistance would be repaid upon sale of the underlying home; (H) providing for limited Federal development and oversight of the sale of catastrophe insurance in high- risk areas during periods of relative unavailability; and (I) facilitating further growth of the catastrophe bond marketplace and other competitive alternatives to the traditional insurance and reinsurance marketplace; (5) the present and long-term financial condition of State residual markets and catastrophe funds in high-risk regions, including the likelihood of insolvency following a natural catastrophe, the concentration of risks within such funds, the reliance on post-event assessments and State funding, the adequacy of rates, and the degree to which such entities have been actuarially solvent in comparison to comparably sized private insurers; (6) the need for strengthened land use regulations and building codes in States at high risk for natural catastrophes, and methods to strengthen the risk assessment and enforcement of structural mitigation and vulnerability reduction measures, such as zoning and building code compliance; (7) the ability of the private insurance market in the United States-- (A) to cover insured losses caused by natural catastrophes, including an estimate of the maximum amount of insured losses that could be sustained during a single year and the probability of natural catastrophes occurring in a single year that would inflict more insured losses than the United States insurance and reinsurance markets could sustain; and (B) to recover after covering substantial insured losses caused by natural catastrophes; (8) the impact that demographic trends could have on the amount of insured losses inflicted by future natural catastrophes; (9) the appropriate role, if any, for the Federal Government in stabilizing the property and casualty insurance and reinsurance markets; and (10) the role of the Federal, State, and local governments in providing incentives for feasible risk mitigation efforts. SEC. 6. TIMING. Before the beginning of the 2008 hurricane season, which for purposes of this section shall be considered to be June 1, 2008, the Commission shall submit to the Committee on Financial Services of the House of Representatives and the Committee on Banking, Housing, and Urban Affairs of the Senate a final report containing-- (1) a detailed statement of the findings and assessments conducted by the Commission pursuant to section 5; and (2) specific and detailed recommendations for legislative, regulatory, administrative, or other actions at the Federal, State, or local levels that the Commission considers appropriate, in accordance with the requirements of section 5. SEC. 7. POWERS OF THE COMMISSION. (a) Meetings; Hearings.--The Commission may hold such hearings, sit and act at such times and places, take such testimony, and receive such evidence as the Commission considers necessary to carry out the purposes of this Act. Members may attend meetings of the Commission and vote in person, via telephone conference, or via video conference. (b) Authority of Members or Agents of the Commission.--Any member or agent of the Commission may, if authorized by the Commission, take any action which the Commission is authorized to take by this Act. (c) Obtaining Official Data.-- (1) Authority.--Notwithstanding any provision of section 552a of title 5, United States Code, the Commission may secure directly from any department or agency of the United States any information necessary to enable the Commission to carry out this Act. (2) Procedure.--Upon request of the Chairperson, the head of such department or agency shall furnish to the Commission the information requested. (d) Postal Services.--The Commission may use the United States mails in the same manner and under the same conditions as other departments and agencies of the Federal Government. (e) Administrative Support Services.--Upon the request of the Commission, the Administrator of General Services shall provide to the Commission, on a reimbursable basis, any administrative support services necessary for the Commission to carry out its responsibilities under this Act. (f) Acceptance of Gifts.--The Commission may accept, hold, administer, and utilize gifts, donations, and bequests of property, both real and personal, for the purposes of aiding or facilitating the work of the Commission. The Commission shall issue internal guidelines governing the receipt of donations of services or property. (g) Volunteer Services.--Notwithstanding the provisions of section 1342 of title 31, United States Code, the Commission may accept and utilize the services of volunteers serving without compensation. The Commission may reimburse such volunteers for local travel and office supplies, and for other travel expenses, including per diem in lieu of subsistence, as authorized by section 5703 of title 5, United States Code. (h) Federal Property and Administrative Services Act of 1949.-- Subject to the Federal Property and Administrative Services Act of 1949, the Commission may enter into contracts with Federal and State agencies, private firms, institutions, and individuals for the conduct of activities necessary to the discharge of its duties and responsibilities. (i) Limitation on Contracts.--A contract or other legal agreement entered into by the Commission may not extend beyond the date of the termination of the Commission. SEC. 8. COMMISSION PERSONNEL MATTERS. (a) Travel Expenses.--The members of the Commission shall be allowed travel expenses, including per diem in lieu of subsistence, at rates authorized for employees of agencies under subchapter I of chapter 57 of title 5, United States Code, while away from their homes or regular places of business in the performance of services for the Commission. (b) Subcommittees.--The Commission may establish subcommittees and appoint members of the Commission to such subcommittees as the Commission considers appropriate. (c) Staff.--Subject to such policies as the Commission may prescribe, the Chairperson may appoint and fix the pay of such additional personnel as the Chairperson considers appropriate to carry out the duties of the Commission. The Commission shall confirm the appointment of the executive director by majority vote of all of the members of the Commission. (d) Applicability of Certain Civil Service Laws.--Staff of the Commission may be-- (1) appointed without regard to the provisions of title 5, United States Code, governing appointments in the competitive service; and (2) paid without regard to the provisions of chapter 51 and subchapter III of chapter 53 of that title relating to classification and General Schedule pay rates, except that an individual so appointed may not receive pay in excess of the annual rate of basic pay prescribed for GS-15 of the General Schedule under section 5332 of that title. (e) Experts and Consultants.--In carrying out its objectives, the Commission may procure temporary and intermittent services of consultants and experts under section 3109(b) of title 5, United States Code, at rates for individuals which do not exceed the daily equivalent of the annual rate of basic pay prescribed for GS-15 of the General Schedule under section 5332 of that title. (f) Detail of Government Employees.--Upon request of the Chairperson, any Federal Government employee may be detailed to the Commission to assist in carrying out the duties of the Commission-- (1) on a reimbursable basis; and (2) such detail shall be without interruption or loss of civil service status or privilege. SEC. 9. TERMINATION. The Commission shall terminate 90 days after the date on which the Commission submits its report under section 6. SEC. 10. AUTHORIZATION OF APPROPRIATIONS. There are authorized to be appropriated to the Commission, such sums as may be necessary to carry out this Act, to remain available until expended.

Commission on Natural Catastrophe Risk Management and Insurance Act of 2007 - Establishes the Commission on Natural Catastrophe Risk Management and Insurance to report to Congress on the natural catastrophe insurance marketplace, including: (1) the extent to which insurance costs and availability are affected by specified factors; (2) which factors the federal government should address to increase catastrophe insurance availability and competitiveness; and (3) actions the federal government can undertake to achieve this goal without requiring a long-term cross-subsidy from taxpayers. Requires the Commission to report to certain congressional committees before the beginning of the 2008 hurricane season.

three hundred forty nine patients who were diagnosed with colorectal cancer at the korea university guro hospital from january 2002 to december 2009 , who had surgical procedure such as right hemicolectomy , left hemicolectomy , sigmoidectomy , anterior resection , and abdominoperineal resection and had no prior history of neo - adjuvant chemotherapy were included in this study . clinicopathologic data such as sex , age , and distant metastasis were collected from medical records . all of the cases were reviewed and classified according to the criteria of the world health organization ( who ) classification.21 pathologic staging was reviewed based on the tnm staging system of the american joint committee on cancer.22 the patients were grouped according to age , sex , location , tnm stage , tumor invasion , presence of lymph node metastasis , presence of distant metastasis , and histologic grade . this study obtained approval from the institutional review board of korea university guro hospital ( kuggr-2011 - 015 ) . hematoxylin and eosin - stained glass slides of selected patients were reviewed for construction of tissue microarray ( tma ) . one 2.0 mm core of tumor per case and one 2.0 mm core of representatively sampled normal mucosa were arrayed . tma blocks were cut into 4 m slices for immunohistochemical staining . a standard streptavidin - biotin peroxidase complex method was used . after deparaffinization and rehydration , slides were heated in a microwave oven for 15 minutes in 10 mm citrate buffer ( ph 6.0 ) and treated with 3% hydrogen peroxide for 20 minutes . the following antibodies were used : sirt1 ( 1:50 , clone h-300 , santa cruz biotechnology , santa cruz , ca , usa ) , dbc1 ( 1:100 , polyclonal , abcam , cambridge , ma , usa ) , -catenin ( 1:500 , clone -catenin-1 , dako , carpinteria , ca , usa ) , survivin ( 1:400 , polyclonal , novus , littleton , ma , usa ) , and p53 ( 1:500 , clone do-7 , novocastra , newcastle upon tyne , uk ) . each case was evaluated by estimating the percentages and intensity of tumor cells showing a nuclear staining pattern . immunostaning for sirt1 was considered positive if 30% or more of the tumor cells were stained with an antibody , referring to other previous studies using the same antibody.12,15 immunostaining for dbc1 was considered negative if more than 30% of tumor cells showed loss of expression , because dbc1 was expressed in all of the normal mucosa with nuclear staining pattern and at least moderate intensity ; the cutoff value of 30% was chosen because dbc1 is known as negative regulator of sirt1 , so it was adjusted to the cutoff value of sirt1 . survivin was also expressed in normal colonic mucosa with moderate intensity and is known to be inhibited by sirt1 . in the same manner , immunostaining for survivin was considered negative if more than 30% of tumor cells showed loss of expression . immunostaining for -catenin was considered positive if the tumor cells showed cytoplasmic and/or nuclear expression , so called altered expression . immunostaining for p53 was considered positive if more than 10% of tumor cells were stained with the antibody , according to previous guidelines.23 all statistical analyses were performed using ibm spss ver . the endpoint of follow - up was the date of final contact or the date of death through july 2011 . correlations between immunohistochemical expression and the clinicopathological characteristics were analyzed by pearson 's tests . overall survival was calculated as the time from the date of the surgery to the date of death or final contact . univariate and multivariate analyses for overall survival were performed using the cox proportional hazard model . in all statistical analyses , three hundred forty nine patients who were diagnosed with colorectal cancer at the korea university guro hospital from january 2002 to december 2009 , who had surgical procedure such as right hemicolectomy , left hemicolectomy , sigmoidectomy , anterior resection , and abdominoperineal resection and had no prior history of neo - adjuvant chemotherapy were included in this study . clinicopathologic data such as sex , age , and distant metastasis were collected from medical records . all of the cases were reviewed and classified according to the criteria of the world health organization ( who ) classification.21 pathologic staging was reviewed based on the tnm staging system of the american joint committee on cancer.22 the patients were grouped according to age , sex , location , tnm stage , tumor invasion , presence of lymph node metastasis , presence of distant metastasis , and histologic grade . this study obtained approval from the institutional review board of korea university guro hospital ( kuggr-2011 - 015 ) . hematoxylin and eosin - stained glass slides of selected patients were reviewed for construction of tissue microarray ( tma ) . one 2.0 mm core of tumor per case and one 2.0 mm core of representatively sampled normal mucosa were arrayed . tma blocks were cut into 4 m slices for immunohistochemical staining . a standard streptavidin - biotin peroxidase complex method was used . after deparaffinization and rehydration , slides were heated in a microwave oven for 15 minutes in 10 mm citrate buffer ( ph 6.0 ) and treated with 3% hydrogen peroxide for 20 minutes . the following antibodies were used : sirt1 ( 1:50 , clone h-300 , santa cruz biotechnology , santa cruz , ca , usa ) , dbc1 ( 1:100 , polyclonal , abcam , cambridge , ma , usa ) , -catenin ( 1:500 , clone -catenin-1 , dako , carpinteria , ca , usa ) , survivin ( 1:400 , polyclonal , novus , littleton , ma , usa ) , and p53 ( 1:500 , clone do-7 , novocastra , newcastle upon tyne , uk ) . each case was evaluated by estimating the percentages and intensity of tumor cells showing a nuclear staining pattern . immunostaning for sirt1 was considered positive if 30% or more of the tumor cells were stained with an antibody , referring to other previous studies using the same antibody.12,15 immunostaining for dbc1 was considered negative if more than 30% of tumor cells showed loss of expression , because dbc1 was expressed in all of the normal mucosa with nuclear staining pattern and at least moderate intensity ; the cutoff value of 30% was chosen because dbc1 is known as negative regulator of sirt1 , so it was adjusted to the cutoff value of sirt1 . survivin was also expressed in normal colonic mucosa with moderate intensity and is known to be inhibited by sirt1 . in the same manner , immunostaining for survivin was considered negative if more than 30% of tumor cells showed loss of expression . immunostaining for -catenin was considered positive if the tumor cells showed cytoplasmic and/or nuclear expression , so called altered expression . immunostaining for p53 was considered positive if more than 10% of tumor cells were stained with the antibody , according to previous guidelines.23 all statistical analyses were performed using ibm spss ver . 20 ( ibm , armonk , ny , usa ) . the endpoint of follow - up was the date of final contact or the date of death through july 2011 . correlations between immunohistochemical expression and the clinicopathological characteristics were analyzed by pearson 's tests . overall survival was calculated as the time from the date of the surgery to the date of death or final contact . univariate and multivariate analyses for overall survival were performed using the cox proportional hazard model . in all statistical analyses , the expression of sirt1 and dbc1 in colorectal cancer was observed in 235 ( 67% ) and 183 ( 52% ) patients with nuclear staining pattern , respectively . 1 ) . sirt1 and dbc1 were not significantly related to clinicopathological features such as age , sex , location , stage , invasion depth of tumor , lymph node metastasis , distant metastasis , or histologic grade ( table 1 ) . all of the sampled normal mucosa showed membranous expression of -catenin with weak or moderate intensity . the nuclear and/or cytoplasmic expression of -catenin was observed in 246 ( 70% ) patients ( fig . the altered expression of -catenin was correlated with left - located tumor ( p=0.001 ) , absence of distant metastasis ( p=0.027 ) , and non - poorly differentiation ( p=0.026 ) ( table 1 ) . survivin was expressed in all of the normal mucosa with moderate or strong intensity with nuclear staining pattern . the loss of expression of survivin was observed in 156 ( 45% ) patients ( fig . the loss of nuclear expression of survivin was correlated with higher t stage ( p=0.004 ) ( table 1 ) . cytoplasmic expression of survivin was not related to overall survival or clinicopathological features such as age , sex , location , stage , invasion depth of tumor , lymph node metastasis , distant metastasis , or histologic grade . expression of p53 was positively correlated with tnm stage ( p=0.018 ) and distant metastasis ( p=0.001 ) ( table 1 ) . the expression of sirt1 was significantly related to the expression of dbc1 ( p<0.001 ) , -catenin ( p=0.001 ) , and survivin ( p=0.002 ) . the expression of dbc1 was significantly related to the expression of -catenin ( p=0.006 ) and survivin ( p<0.001 ) . expression of sirt1 and related proteins and their correlations are summarized in table 2 . for univariate analysis of overall survival , analyzed clinicopathologic features , old age ( 65 ) ( p=0.005 ) , high tnm stage ( stages iii and iv ) ( p<0.001 ) , left - side tumor ( p=0.034 ) , invasion of more than the muscularis propria ( p=0.024 ) , presence of lymph node metastasis ( p=0.001 ) , presence of distant metastasis ( p<0.001 ) , and poorly differentiated histologic grade ( p=0.001 ) were significantly associated with shorter overall survival . the overexpression of sirt1 and altered expression of -catenin showed significant association with better overall survival ( p=0.029 and p=0.008 , respectively ) . however , the expression of dbc1 ( p=0.221 ) , survivin ( p=0.537 ) , and p53 ( p=0.218 ) was not associated with overall survival . the factors considered in the analysis were age , tumor location , tumor stage , histologic grade , and the expression of sirt1 and -catenin . on multivariate analysis , age , tumor stage , histologic grade , and sirt1 expression were independent prognostic factors significantly associated with overall survival . the expression of sirt1 and dbc1 in colorectal cancer was observed in 235 ( 67% ) and 183 ( 52% ) patients with nuclear staining pattern , respectively . 1 ) . sirt1 and dbc1 were not significantly related to clinicopathological features such as age , sex , location , stage , invasion depth of tumor , lymph node metastasis , distant metastasis , or histologic grade ( table 1 ) . all of the sampled normal mucosa showed membranous expression of -catenin with weak or moderate intensity . the nuclear and/or cytoplasmic expression of -catenin was observed in 246 ( 70% ) patients ( fig . the altered expression of -catenin was correlated with left - located tumor ( p=0.001 ) , absence of distant metastasis ( p=0.027 ) , and non - poorly differentiation ( p=0.026 ) ( table 1 ) . survivin was expressed in all of the normal mucosa with moderate or strong intensity with nuclear staining pattern . the loss of expression of survivin was observed in 156 ( 45% ) patients ( fig . the loss of nuclear expression of survivin was correlated with higher t stage ( p=0.004 ) ( table 1 ) . cytoplasmic expression of survivin was not related to overall survival or clinicopathological features such as age , sex , location , stage , invasion depth of tumor , lymph node metastasis , distant metastasis , or histologic grade . expression of p53 was positively correlated with tnm stage ( p=0.018 ) and distant metastasis ( p=0.001 ) ( table 1 ) . the expression of sirt1 was significantly related to the expression of dbc1 ( p<0.001 ) , -catenin ( p=0.001 ) , and survivin ( p=0.002 ) . the expression of dbc1 was significantly related to the expression of -catenin ( p=0.006 ) and survivin ( p<0.001 ) . for univariate analysis of overall survival , a cox proportional hazard model was used ( table 3 ) . among analyzed clinicopathologic features , old age ( 65 ) ( p=0.005 ) , high tnm stage ( stages iii and iv ) ( p<0.001 ) , left - side tumor ( p=0.034 ) , invasion of more than the muscularis propria ( p=0.024 ) , presence of lymph node metastasis ( p=0.001 ) , presence of distant metastasis ( p<0.001 ) , and poorly differentiated histologic grade ( p=0.001 ) were significantly associated with shorter overall survival . the overexpression of sirt1 and altered expression of -catenin showed significant association with better overall survival ( p=0.029 and p=0.008 , respectively ) . however , the expression of dbc1 ( p=0.221 ) , survivin ( p=0.537 ) , and p53 ( p=0.218 ) was not associated with overall survival . the factors considered in the analysis were age , tumor location , tumor stage , histologic grade , and the expression of sirt1 and -catenin . on multivariate analysis , age , tumor stage , histologic grade , and sirt1 expression were independent prognostic factors significantly associated with overall survival . the present study examined the immunohistochemical expressions of sirt1 , dbc1 , -catenin , survivin , and p53 in human colorectal cancer and their relationships with clinicopathologic factors and prognostic significance . only a few studies that have examined expression of sirt1 and its relationship to prognosis in colorectal cancer.8,9 our study is the first to examine expression of sirt1 and its relationship to expression of other related markers , dbc1 , -catenin , survivin , and p53 in colorectal cancer with human tissue . as mentioned above , sirt1 might act as a tumor promoter by inhibiting tumor suppressor genes and might also act as a tumor suppressor by repressing several oncogenes.5 - 7 a number of recent studies have revealed that sirt1 expression was increased in many human malignant tumors.3,4 however , the role of sirt1 in human malignant tumors is controversial . some previous studies have reported that sirt1 overexpression was associated with shorter overall survival or poor prognostic indicators in breast and gastric carcinoma.12,15 in contrast to these studies , one study reported that sirt1 expression was gradually decreased as tumor progression and was associated with better overall survival in colorectal adenocarcinoma.8 our study also revealed that expression of sirt1 was significantly related to better overall survival . taken together with these reports , our results suggest that sirt1 expression is related to better prognosis in colorectal cancer and that sirt1 acts differently depending on the specific organ or type of tumor involved . our study examined the expression of dbc1 and its relationship to prognosis in colorectal cancer . a recent study revealed that dbc1 overexpression was related to poor prognosis in colorectal cancer.16 however , our study failed to determine the relationship between the expression of dbc1 and prognosis in colorectal cancer dbc1 is known as negative regulator of sirt1.14 the present study found that the expressions of sirt1 and dbc1 were positively correlated with each other ( p<0.001 ) . we could surmise that this result might be due to a close functional relationship between sirt1 and dbc1 in carcinogenesis . however , further functional study will be needed to investigate the relationship between sirt1 and dbc1 . -catenin is a key regulator of wnt signaling and is also known as an important regulator in cancer development.17 the adenomatous polyposis coli ( apc ) protein negatively regulates the wnt signaling pathway.24 the apc gene mutation results in nuclear accumulation of -catenin which becomes phosphorylated and is eventually degraded via the apc - dependent ubiquitin - proteosome pathway.25 in our study , normal colonic mucosa showed membranous staining of -catenin . the altered expression of -catenin was negatively correlated with the presence of distant metastasis and poorly differentiated histologic grade . this is a conflicting result to previous study which reported that altered expression of -catenin was independently associated with poor prognosis in colon cancer.18 therefore , the relationship between -catenin expression and prognosis remains controversial , and further studies on wnt/-catenin and target gene activity and protein expression are needed . survivin is a protein that is an inhibitor of apoptosis , and is overexpressed in various cancers.19 in our study , normal colonic mucosa showed expression of survivin with nuclear staining pattern . some studies have reported that altered expression of survivin was related to poor prognosis in several tumors.26,27 another study reported that cytoplasmic expression of survivin was associated with a poor prognosis , but nuclear overexpression was related to a better prognosis.28 our study also showed that the loss of nuclear expression of survivin was related to advanced invasion depth . cytoplasmic expression of survivin was not associated with prognostic indicators ; however , loss of nuclear expression of survivin may be related to poor prognosis in colorectal cancer . sirt1 is considered to inhibit p53-mediated apoptosis through deacetylation of p53.5 however , there was no relationship between the expression of sirt1 and p53 in our study and a previous study.11 overexpression of sirt1 was related to better overall survival . if sirt1 predominantly acts like a tumor suppressor , it might have less effect on p53 in colorectal cancer . the finding that sirt1 expression was correlated with altered expression of -catenin and survivin which are considered to be oncoproteins , supports the hypothesis that sirt1 predominantly acts as a tumor suppressor and might have less effect on p53 in colorectal cancer . through multivariate analysis , we revealed that sirt1 was an independent prognostic indicator for overall survival but -catenin was not . however , to ensure our hypothesis , further functional study is needed . in summary , although the exact role of sirt1 in colorectal cancer is not clear , nor whether it is a tumor suppressor or promoter , the results of our study suggest that the expression of sirt1 is related to better prognosis and predominantly acts like tumor suppressor in colorectal cancer patients .

backgroundsilent mating type information regulation 2 homolog 1 ( sirt1 ) , an nad+-dependent deacetylase , might act as a tumor promoter by inhibiting p53 , but may also as a tumor suppressor by inhibiting several oncogenes such as -catenin and survivin . deleted in breast cancer 1 ( dbc1 ) is known as a negative regulator of sirt1.methodsimmunohistochemical expressions of sirt1 , dbc1 , -catenin , surviving , and p53 were evaluated using 2 mm tumor cores from 349 colorectal cancer patients for tissue microarray.resultsoverexpression of sirt1 , dbc1 , survivin , and p53 was seen in 235 ( 67% ) , 183 ( 52% ) , 193 ( 55% ) , and 190 ( 54% ) patients , respectively . altered expression of -catenin was identified in 246 ( 70% ) patients . on univariate analysis , overexpression of sirt1 ( p=0.029 ) and altered expression of -catenin ( p=0.008 ) were significantly associated with longer overall survival . expression of sirt1 was significantly related to dbc1 ( p=0.001 ) , -catenin ( p=0.001 ) , and survivin ( p=0.002 ) , but not with p53 . on multivariate analysis , age , tumor stage , differentiation , and expression of sirt1 were independent prognostic factors significantly associated with overall survival.conclusionssirt1 overexpression is a good prognostic factor for colorectal cancer , and sirt1 may interact with -catenin and survivin rather than p53 .

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convulsions and loss of consciousness in patients can be caused by arrhythmias , conduction disorders or epilepsy . when syncope is misinterpreted as epilepsy , this may not only lead to the unnecessary use of anticonvulsant drugs but , more importantly , life - threatening arrhythmias can be missed which may lead to sudden unexpected death . the aim of this case report is to present a patient with previously unknown noncompaction cardiomyopathy ( nccm ) in whom syncope induced by ventricular tachycardia was misinterpreted as epilepsy , in order to underline the necessity for cardiological assessment in patients with assumed mild epilepsy or syncope of unknown origin . a 57-year - old man without any history of cardiovascular disease was initially referred to the neurologist for analysis of collapse . an electroencephalogram ( eeg ) revealed an evident paroxysmal disturbance of function in the right frontotemporal lobe . he was diagnosed with mild focal epilepsy and was treated with levetiracetam without any result . a second eeg showed no eeg abnormalities ; however , a simultaneous electrocardiogram ( ecg ) showed a sudden onset of a wide complex tachycardia when the patient collapsed ( fig . 1a fragment of a 24-h eeg which shows a sudden onset of a wide complex tachycardia on a simultaneously recorded ecg , while there is no electrical disturbance in the eeg leads ( only one of the eeg is shown , o1-av ) a fragment of a 24-h eeg which shows a sudden onset of a wide complex tachycardia on a simultaneously recorded ecg , while there is no electrical disturbance in the eeg leads ( only one of the eeg is shown , o1-av ) one year before admission the patient started to suffer from dizziness and collapse several times a day . he did not complain of palpitations or chest pain . in the last 2 months ordinary physical activity resulted in fatigue and dyspnoea ( nyha class ii ) . besides smoking 10 ecg showed a sinus rhythm with normal conduction times and no st - t deviations . transthoracic echocardiography demonstrated an impaired systolic left ventricular function with an ejection fraction of 45 % . magnetic resonance imaging ( mri ) of the heart confirmed the diagnosis of nccm ( fig . 2 ) . telemetry monitoring showed monomorphic non - sustained ventricular tachycardias ( nsvt ) with a right bundle branch block configuration , a superior axis in the frontal plane and a frequency of 150170 beats / min ( fig . 3 ) . during these vts the patient noticed dizziness without loss of consciousness . 2mri of the heart confirmed the diagnosis of noncompaction cardiomyopathy , excessive trabeculation ( arrow ) lv = left ventricle , rv = right ventriclefig . the vt originated from the infero - apical left ventricle mri of the heart confirmed the diagnosis of noncompaction cardiomyopathy , excessive trabeculation ( arrow ) lv = left ventricle , rv = right ventricle telemetric rhythm observation : non - sustained vt , monomorphic , 170 complexes/ min . the vt originated from the infero - apical left ventricle the patient was treated with a beta - blocker and an ace - inhibitor which reduced the number and duration of non - sustained vts and the patient became asymptomatic . considering the nccm with poor systolic lv function and symptomatic vts without a treatable arrhythmogenic substrate , there was a class i ( evidence level a ) indication for icd implantation according to the guidelines for the management of patients with ventricular arrhythmia and the prevention of sudden cardiac death ( scd ) . transient loss of consciousness ( t - loc ) is defined as an abrupt , self - limiting complete loss of consciousness . cardiac syncope is caused by reduced global cerebral perfusion due to a sudden decrease in cardiac output . arrhythmia and structural heart disease such as aortic stenosis and cardiomyopathy are the most important cardiac causes of syncope . recognising cardiac syncope is of utmost importance because of all patients with t - loc , the ones with cardiac syncope have the highest likelihood of subsequent sudden death . kapoor et al . showed in 1983 that in the 12 months following presentation with cardiac syncope , sudden death was found to be six times more common than in patients with noncardiac syncope . the patient of this case report suffered from syncope induced by a ventricular tachycardia as a consequence of noncompaction cardiomyopathy ( nccm ) . even with the help of modern imaging modalities , such as contrast echocardiography and mri , diagnosing nccm can be difficult . the clinical spectrum of nccm shows a highly variable clinical presentation , ranging from asymptomatic to severely symptomatic with end - stage heart failure , lethal arrhythmias , and/or thromboembolic events . there is a high prevalence of , mostly asymptomatic , cardiac disease ( 26 % ) among first- and second - degree family members of patients with nccm . this warrants genetic counselling , dna diagnostics , and cardiological family screening and offers an opportunity for early intervention [ 12 , 13 ] . . showed in a relatively large group of nccm patients that icd therapy for primary or secondary prevention of scd was appropriate in both groups supporting the application of icd in these patients . however , although icd seems to be an effective option for preventing scd , data on the long - term follow - up of nccm patients remain scarce . a substantial number of the patients with t - loc have cardiac syncope and these patients have a substantial risk of subsequent sudden death . sudden death may be preventable in these patients , which underlines the necessity for a cardiological assessment in patients with syncope .

convulsions and loss of consciousness can be caused by , among other things , arrhythmias , conduction disorders or epilepsy . in clinical practice it can be difficult to distinguish between these causes of syncope , even for well - trained specialists . patients with cardiac syncope have a substantial risk of subsequent sudden death . we present a patient with previously unknown noncompaction cardiomyopathy in whom syncope induced by ventricular tachycardia was misinterpreted as epilepsy . we present this case report in order to underline the necessity for cardiological assessment in patients with assumed mild epilepsy or syncope of unknown origin .

the current observations , such as sneia ( supernovae type ia ) , cmb ( cosmic microwave background ) and large scale structure , converge on the fact that a spatially homogeneous and gravitationally repulsive energy component , referred as dark energy , accounts for about @xmath1 % of the energy density of universe . some heuristic models that roughly describe the observable consequences of dark energy were proposed in recent years , a number of them stemming from a certain physics @xcite and the others being purely phenomenological @xcite . dark energy can even behave as a phantom and effectively violate the weak energy condition@xcite . in various cosmological models , fundamental quantities are either geometrical ( if they are constructed from a spacetime geometry directly ) or physical ( if they depend upon physical fields ) . physical quantities are certainly model - dependent , while geometrical quantites are more universal . about thirty years ago , the bouncing cosmological model with torsion was suggested in ref.@xcite , but the torsion was imagined as playing role only at high densities in the early universe . goenner et al . made a general survey of the torsion cosmology @xcite , in which the equations for all the pgt ( poincar gauge theory of gravity ) cases were discussed although they only solved in detail a few particular cases . recently some authors have begun to study torsion as a possible reason of the accelerating universe @xcite . nester and collaborators @xcite consider an accounting for the accelerated universe in term of a riemann - cartan geometry : dynamic scalar torsion . they explore the possibility that the dynamic pgt connection , reflecting the nature of dynamic pgt torsion , provides the accelerating force . with the usual assumptions of homogeneity and isotropy in cosmology and specific cases of the suitable parameters and initial conditions , they find that torsion field could play a role of dark energy . one of the motivation was to avoid singularities in the initial investigations of torsion cosmology @xcite . however , it soon was found that non - linear torsion effects were more likely to produce stronger singularities @xcite . the non - linear effects turn out to play a key role for the outstanding present day mystery : the accelerated universe . in the various pgt , the connection dynamics decomposed into six modes with certain spin and parity : @xmath2 , @xmath3 , @xmath4 . some investigations showed that @xmath4 may well be the only acceptable dynamic pgt torsion modes @xcite . the pseudoscalar mode @xmath5 is naturally driven by the intrinsic spin of elementary fermions , therefore it naturally interacts with such sources . consequently , it is generally thought that axial torsion must be small and have small effects at the late time of cosmological evolution . this is a major reason why one does not focus on this mode at the late time . on the other hand , the scalar mode @xmath6 does not interact in any direct obvious fashion with any known type of matter @xcite , therefore one can imagine it as having significant magnitude and yet not being conspicuously noticed . furthermore , there is a critical non - zero value for the affine scalar curvature since @xmath6 mode can interact indirectly through the non - linear equations . the homogeneity and isotropy of cosmology have received strong confirmation from modern observations , which greatly restrict the possible types of non - vanishing fields . under the assumption of homogeneity and isotropy , @xmath6 mode has only a time component and it can be specified as the gradient of a time - dependent function . therefore , the cosmological models with the scalar mode offer a situation where dynamic torsion may lead to observable effect at late time . we emphasize again that one does not focus on the early universe , where one could indeed expect large effects ( though their signature would have to be separated from other large effects ) , and substitutionally asks about traces of torsion effects at the late time of cosmological evolution @xcite . obviously , the fine - tuning problem is one of the most important issues for the torsion cosmology @xcite . and a good model should limit the fine - tuning as much as possible . the dynamical attractor of the cosmological system has been employed to make the later time behaviors of the model insensitive to the initial condition of the field and thus alleviates the fine - tuning problem @xcite . furthermore , nester et al @xcite have shown that the hubble parameter and @xmath7 have an oscillatory form for the scalar torsion cosmology . the traditional geometrical parameters , i.e. , the hubble parameter @xmath8 and the deceleration parameter @xmath9 , are two elegant choices to describe the expansion state of universe but they can not distinguish various accelerating mechanism uniquely , because a quite number of models may just correspond to the same current values of @xmath10 and @xmath11 . however , sahni , saini , starobinsky and alam @xcite have introduced the statefinder pair @xmath12 : @xmath13 , @xmath14 . it is obviously a natural next step beyond @xmath10 and @xmath11 . fortunately , as is shown in the literatures @xcite , the statefinder parameters which are also geometrical diagnostics , are able to differentiate a series of cosmological models successfully . using the discussion of statefinder parameters in the scalar torsion cosmology , we explain easily why the present field equations modify the expansion of the universe only at late time . if the evolving trajectory of statefinder have a decelerating phase ( @xmath15 ) at early time , then we can understand why the expansion of the universe until @xmath16 remains unchanged in the scalar torsion models . in this paper , we apply the statefinder diagnostics to the torsion cosmology . we find that there are some characteristics of statefinder parameters for the torsion cosmology that can be distinguished from the other cosmological models . the statefinder diagnostics show that the universe naturally has an accelerating expansion at low redshifts ( late time ) and a decelerating expansion at high redshifts ( early time ) . therefore , scalar torsion cosmology can avoid some of the problems which occur in other models . especially , the effect of torsion can make the expansion rate oscillate when torsion parameter @xmath17 or @xmath18 . whether the universe has properties which are easier to explain within the scalar torsion context is a remarkable possibility demanding further exploration . the oscillatory feature of hubble parameter had earlier been reported for the braneworld cosmology @xcite and the quasi - steady state cosmology @xcite . we show that statefinder diagnostic has a direct bearing on the critical points of the dynamical system . one of the most interesting characteristic of the trajectories is that there are loop and curves with the shape of tadpole in the case of the torsion parameter @xmath19 . in this case , we fit the scalar torsion model to current type ia supernova data and find it is consistent with the observations . furthermore , we analyze preliminarily the relevance for realistic observation of the found statefinder parameters . pgt @xcite has been regarded as an interesting alternative to general relativity because of its gauge structure and geometric properties . pgt based on a riemann - cartan geometry , allows for dynamic torsion in addition to curvature . the affine connection of the riemann - cartan geometry is @xmath20 where @xmath21 is the levi - civita connection and @xmath22 is the torsion tensor . meantime , the ricci curvature and scalar curvature can be written as @xmath23 where @xmath24 and @xmath25 are the riemannian ricci curvature and scalar curvature , respectively , and @xmath26 is the covariant derivative with the levi - civita connection ( for a detailed discussion see ref . . theoretical analysis of pgt led us to consider tendentiously dynamic `` scalar mode '' . in this case , the restricted expression of the torsion can be written as @xcite @xmath27\kappa},\label{trestrct}\ ] ] where the vector @xmath28 is the trace of the torsion . then , the ricci curvature and scalar curvature can be expressed as @xmath29 the gravitational lagrangian density for the scalar mode is @xmath30 where @xmath31 and @xmath0 is a torsion parameter . consider that the parameter @xmath32 is associated with quadratic scalar curvature term @xmath33 , so that @xmath32 should be positive @xcite . therefore , the field equations of the scalar mode are @xmath34 where @xmath35 is the source energy - momentum tensor and @xmath36 is the contribution of the scalar torsion mode to the effective total energy - momentum tensor : @xmath37 since current observations favor a flat universe , we will work in the spatially flat robertson - walker metric @xmath38 $ ] , where @xmath39 is the scalar factor . this engenders the riemannian ricci curvature and scalar curvature : @xmath40 where @xmath39 is the scalar factor , and @xmath10 is the hubble parameter . the torsion @xmath41 should also be only time dependent , therefore one can let @xmath42 ( @xmath43 is the torsion field ) and the spatial parts vanish . the corresponding equations of motion in the matter - dominated era are as follows @xmath44 where @xmath45 and the energy density of matter component @xmath46 one can scale the variables and the parameters as @xmath47 where @xmath48 is the present value of hubble parameter and @xmath49 is the planck length . under the transform ( [ scale ] ) , eqs . ( [ dth])-([dtr ] ) remain unchanged . after transform , new variables @xmath50 , @xmath10 , @xmath51 and @xmath52 , and new parameters @xmath53 , @xmath0 , @xmath54 and @xmath32 are all dimensionless . obviously , the newtonian limit requires @xmath55 . for the case of scalar torsion mode , the effective energy - momentum tensor can be represented as @xmath56\,,\label{torpre}\end{aligned}\ ] ] and the off - diagonal terms vanish . the effective energy density @xmath57 which is deduced from general relativity . @xmath58 is an effective pressure , and the effective equation of state is @xmath59 which is induced by the dynamic torsion . , the temporal component of the torsion @xmath51 , the affine scalar curvature @xmath52 and the deceleration parameter @xmath11 as functions of time . we have chosen the parameters @xmath60 , @xmath61 and the initial values @xmath62 , @xmath63 , @xmath64.,title="fig:",width=264 ] , the temporal component of the torsion @xmath51 , the affine scalar curvature @xmath52 and the deceleration parameter @xmath11 as functions of time . we have chosen the parameters @xmath60 , @xmath61 and the initial values @xmath62 , @xmath63 , @xmath64.,title="fig:",width=268 ] in the case of @xmath65 , nester et al showed that the scalar mode can contribute an oscillating aspect to the expansion rate of the universe @xcite . this oscillatory nature can be illustrated in fig . [ hqevol ] where we have chosen @xmath60 , @xmath61 , @xmath62 , @xmath63 , @xmath64 and set the current time @xmath66 . according to scaling ( [ scale ] ) , the present value of the hubble parameter is unity . obviously , @xmath10 is damped - oscillating at late time and @xmath67 is negative today , which means the expansion of the universe is currently accelerating . the value of @xmath11 turns from positive to negative when the time is around @xmath68 , which is the epoch the universe began to accelerate . however , the above result is dependent on the choice of initial data and the values of the parameters . then , the scalar torsion cosmology is unsuited to solving the fine - tuning problem in the case of @xmath65 . in the following sections , we ll investigate the statefinder and give the dynamics analysis for all ranges of the parameter @xmath0 . for the spatially flat @xmath69cdm model the statefinder parameters correspond to a fixed point @xmath70 while @xmath71 for the standard cold dark matter model ( scdm ) containing no radiation . since the torsion cosmology have used the dynamic scalar torsion ( a geometry quantity in the riemann - cartan spacetime ) , the torsion accelerating mechanism is bound to exhibit an essential distinction in contrast with various dark energy models . therefore , its statefinder diagnostic is sure to reveal differential feature . let us now study the torsion cosmological model in detail . using eqs . ( [ dth])-([fieldrho ] ) , we have the deceleration parameter @xmath72(432a_{1}h^{2})^{-1}\,,\label{torsionq } \end{aligned}\ ] ] and the statefinder parameters @xmath73(108a_{1}bh^{3})^{-1}\,,\nonumber\\ \label{torsionr } \end{aligned}\ ] ] and @xmath74}{3bh\left[(6\mu + br)(36h^{2}-24h\phi + 4\phi^{2}-3r)-54\mu r\right]}\ , . \label{torsions } \end{aligned}\ ] ] in the following we will discuss the statefinder for four differential ranges of the torsion parameter @xmath0 , respectively . firstly , we consider the time evolution of the statefinder pairs @xmath12 and @xmath75 in the case of @xmath76 . in fig . [ planecase4 ] , we plot evolution trajectories in the @xmath77 and @xmath78 planes , where we have chosen @xmath79 and @xmath80 . we see easily that cosmic expansion alternates between deceleration and acceleration in the evolving trajectories of @xmath77 plane , and the amplitude becomes larger and larger as increase of time . the trajectories in the @xmath78 plane is quite complicated , so we mark its sequence by the ordinal number . every odd number curve evolves from finite to infinite , but even number curve evolves from infinite to finite . these are quasi - periodic behaviors which corresponds to the numerical solution of ref . noticeably , the trajectories will never pass @xmath69cdm point @xmath70 . secondly , we discuss the time evolution of the statefinder pairs @xmath12 and @xmath75 for the case of @xmath81 . we plot evolving trajectories in fig . [ planecase3 ] , where we have chosen @xmath82 and @xmath83 . we see clearly that the cosmic acceleration is guaranteed by the dynamic scalar torsion in the evolving trajectories of @xmath77 plane , and the curves will converge into @xmath69cdm point . the evolving trajectories go through a climbing - up stage first , then get into a rolling - down stage in the @xmath78 plane . lastly , trajectories tend to @xmath69cdm point @xmath70 . furthermore , the only one forms a loop that starts from @xmath70 then evolves back to @xmath70 , and others show in the shape of tadpole . and @xmath78 planes for the case of torsion parameter @xmath84 , where we choose the parameters @xmath85 and @xmath86 . the arrows show the direction of the time evolution.,title="fig:",width=264 ] and @xmath78 planes for the case of torsion parameter @xmath84 , where we choose the parameters @xmath85 and @xmath86 . the arrows show the direction of the time evolution.,title="fig:",width=264 ] and @xmath78 planes for the case of torsion parameter @xmath87 , where we choose the parameters @xmath88 and @xmath89 . the arrows show the direction of the time evolution.,title="fig:",width=264 ] and @xmath78 planes for the case of torsion parameter @xmath87 , where we choose the parameters @xmath88 and @xmath89 . the arrows show the direction of the time evolution.,title="fig:",width=264 ] and @xmath90 planes for the case of @xmath91 , where we choose @xmath92 and @xmath93 . the arrows show the direction of the time evolution.,title="fig:",width=264 ] and @xmath90 planes for the case of @xmath91 , where we choose @xmath92 and @xmath93 . the arrows show the direction of the time evolution.,title="fig:",width=257 ] and @xmath78 planes for the case of torsion parameter @xmath94 , where we choose the parameters @xmath95 and @xmath86 . the arrows show the direction of the time evolution.,title="fig:",width=264 ] and @xmath78 planes for the case of torsion parameter @xmath94 , where we choose the parameters @xmath95 and @xmath86 . the arrows show the direction of the time evolution.,title="fig:",width=257 ] thirdly , we discuss the time evolution of the trajectories for the case of @xmath96 . we plot evolving trajectories in fig . [ planecase2 ] , where we have chosen @xmath97 and @xmath98 . obviously , the cosmic acceleration can happen since deceleration parameter is negative . @xmath99 , @xmath100 and @xmath101 become larger and larger first , then less and less as the cosmic time increase . finally , we consider the time evolution of the statefinder pairs @xmath12 and @xmath75 in the case of @xmath18 . in fig . [ planecase1 ] , we plot evolving trajectories in the @xmath77 and @xmath78 planes , where we have chosen @xmath102 and @xmath80 . we find easily that the evolving trajectories analogous to the case of @xmath103 except trajectories pass the @xmath69cdm point . to sum up , it is very interesting to see that the scalar torsion naturally provide the accelerating force in the universe for any torsion parameter @xmath0 . however , it is dependent on torsion parameters that there is a decelerating ( @xmath15 ) expansion before an accelerating ( @xmath104 ) expansion . the statefinder diagnostics show that the universe naturally has an accelerating expansion at low redshifts ( late time ) and a decelerating expansion at high redshifts ( early time ) for the cases of @xmath105 and @xmath18 . obviously , scalar torsion cosmology can avoid some of the problems which occur in other models . if we refuse the possibility of non - positivity of the kinetic energy , we will employ normal assumption , i. e. , @xmath17 . in this case , the effect of torsion can make the expansion rate oscillate . with suitable adjustments of the torsion parameters , it is possible to change the quasi - period of the expansion rate as well as its amplitudes . it is worth noting that the true values of the statefinder parameters of the universe should be determined in model - independent way . in principle , @xmath106 can be extracted from some future astronomical observations , especially the snap - type experiment . why there are new features for the statefinder diagnostic of torsion cosmology ? why the torsion parameter @xmath0 is divided into differential ranges by the statefinder answer is very simple . in fact , the statefinder diagnostic has a direct bearing on the attractor of cosmological dynamics . therefore , we will discuss the dynamic analysis in next section . eqs . ( [ dth])-([dtr ] ) is an autonomous system , so we can use the qualitative method of ordinary differential equations . critical points are always exact constant solutions in the context of autonomous dynamical systems . these points are often the extreme points of the orbits and therefore describe the asymptotic behavior . if the solutions interpolate between critical points they can be divided into a heteroclinic orbit and a homoclinic orbit ( a closed loop ) . the heteroclinic orbit connects two different critical points and homoclinic orbit is an orbit connecting a critical point to itself . in the dynamical analysis of cosmology , the heteroclinic orbit is more interesting @xcite . if the numerical calculation is associated with the critical points , then we will find all kinds of heteroclinic orbits . according to equations ( [ dth])-([dtr ] ) , we can obtain the critical points and study the stability of these points . substituting linear perturbations @xmath107 , @xmath108 and @xmath109 near the critical points into three independent equations , to the first orders in the perturbations , gives the evolution of the linear perturbations , from which we could yield three eigenvalues . stability requires the real part of all eigenvalues to be negative . there are five critical points @xmath110 of the system as follows @xmath111 where @xmath112 , @xmath113 and @xmath114 . the corresponding eigenvalues of the critical points ( i)-(v ) are @xmath115 using eq . ( [ criticalpoints ] ) , we find that there is only a critical point @xmath116 in the case of @xmath76 . from eq . ( [ eigenvalues ] ) , the corresponding eigenvalue is @xmath117 , so @xmath118 is an asymptotically stable focus . if we consider the linearized equations , then eqs . ( [ dth])-([dtr ] ) are reduced to @xmath119 + the linearized system ( [ dthphirlinear ] ) has an exact periodic solution @xmath120 where @xmath121 , @xmath122 , @xmath123 and @xmath124 , @xmath125 and @xmath126 are initial values . obviously , @xmath127 is a critical line of center for the linearized eqs . ( [ hrphips ] ) . in other words , there are only exact periodic solutions for the linearized system , but there are quasi - periodic solutions near the focus for the coupled nonlinear equations . this property of quasi - periodic also appears in the statefinder diagnostic with the case of @xmath76 . @l*15@l critical points & property & @xmath128 & stability + ( ` i ` ) & saddle & @xmath129 & unstable + ( ` ii`)&positive attractor&-1&stable + ( ` iii ` ) & negative attractor&-1&unstable + ( ` iv ` ) & saddle&-1&unstable + ( ` v ` ) & saddle&-1&unstable + @l*15@l critical points & property & @xmath128 & stability + ( ` i ` ) & focus & @xmath130 & stable + ( ` ii`)&saddle&-1&unstable + ( ` iii ` ) & saddle&-1&unstable + ( ` iv ` ) & saddle&-1&unstable + ( ` v ` ) & saddle&-1&unstable + in the case of @xmath131 , the critical point ( ii ) is a late time de sitter attractor and ( iii ) is a negative attractor . the properties of the critical points are shown in table [ cripointsa1l0 ] . the de sitter attractor indicates that torsion cosmology is an elegant scheme and the scalar torsion mode is an interesting geometric quantity for physics . in the dynamical analysis of cosmology , the heteroclinic orbit is more interesting . using numerical calculation , we plot the heteroclinic orbit connects the critical point case ( iii ) to case ( ii ) in fig . [ heteroclinicorbit ] . this heteroclinic orbit is just corresponding to the loop in fig . [ planecase3 ] , which is from @xmath69cdm point to @xmath69cdm point . furthermore , the trajectories with the shape of tadpole correspond to saddles . with @xmath132 . the heteroclinic orbit connects the critical points case ( iii ) to case ( ii ) . we take @xmath133.,width=321 ] with @xmath94 . we take @xmath134 and the initial value @xmath135 . @xmath136 is an asymptotically stable focus point.,width=321 ] in the case of @xmath96 , there is only an unstable saddle @xmath116 where the effective equation of state @xmath128 tends to @xmath129 . therefore , the trajectories in fig . [ planecase2 ] show that @xmath99,@xmath100 and @xmath101 become larger and larger , then less and less as time increases . in the case of @xmath18 , the properties of the critical points are shown in table [ cripointsa1l-1 ] . the trajectories correspond to the stable focus ( see fig . 6 ) and unstable saddles with @xmath137 . therefore , the trajectories pass through the @xmath69cdm point . in ref.@xcite , the authors have compared the numerical values of the torsion model with the observational data , in which they fixed the initial values @xmath48 , @xmath138 and @xmath139 , and torsion parameters @xmath0 and @xmath32 . in this section , we fixed the initial value , then fit the torsion parameters to current type ia supernovae data . the scalar torsion cosmology predict a specific form of the hubble parameter @xmath140 as a function of redshifts @xmath141 in terms of two parameters @xmath0 and @xmath32 when we chose initial values . using the relation between @xmath142 and the comoving distance @xmath143 ( where @xmath141 is the redshift of light emission ) @xmath144 and the light ray geodesic equation in a flat universe @xmath145 where @xmath146 is the scale factor . in general , the approach towards determining the expansion history @xmath140 is to assume an arbitrary ansatz for @xmath140 which is not necessarily physically motivated but is specially designed to give a good fit to the data for @xmath147 . given a particular cosmological model for @xmath148 where @xmath149 are model parameters , the maximum likelihood technique can be used to determine the best fit values of parameters as well as the goodness of the fit of the model to the data . the technique can be summarized as follows : the observational data consist of @xmath150 apparent magnitudes @xmath151 and redshifts @xmath152 with their corresponding errors @xmath153 and @xmath154 . these errors are assumed to be gaussian and uncorrelated . each apparent magnitude @xmath155 is related to the corresponding luminosity distance @xmath156 by @xmath157 + 25,\ ] ] where @xmath158 is the absolute magnitude . for the distant sneia , one can directly observe their apparent magnitude @xmath159 and redshift @xmath141 , because the absolute magnitude @xmath158 of them is assumed to be constant , i.e. , the supernovae are standard candles . obviously , the luminosity distance @xmath147 is the ` meeting point ' between the observed apparent magnitude @xmath160 and the theoretical prediction @xmath140 . usually , one define distance modulus @xmath161 and express it in terms of the dimensionless ` hubble - constant free ' luminosity distance @xmath162 defined by@xmath163 as @xmath164 where the zero offset @xmath165 depends on @xmath48 ( or @xmath166 ) as @xmath167 the theoretically predicted value @xmath168 in the context of a given model @xmath169 can be described by @xcite @xmath170 therefore , the best fit values for the torsion parameters ( @xmath171 ) of the model are found by minimizing the quantity @xmath172 ^ 2}{\sigma_i^2}.\ ] ] since the nuisance parameter @xmath165 is model - independent , its value from a specific good fit can be used as consistency test of the data @xcite and one can choose _ a priori _ value of it ( equivalently , the value of dimensionless hubble parameter @xmath166 ) or marginalize over it thus obtaining @xmath173 where @xmath174 ^ 2}{\sigma_i^2},\ ] ] @xmath175}{\sigma_i^2},\ ] ] and @xmath176 in the latter approach , instead of minimizing @xmath177 , one can minimize @xmath178 which is independent of @xmath165 . the eqs . ( [ gradr]-[tort ] ) can be solved explicitly by a series in the form @xmath179,\ ] ] where @xmath180 and @xmath181 using the general relation between hubble parameter @xmath182 and the redshift @xmath141 , @xmath141 can be written as a function of @xmath50 @xmath183}-1,\ ] ] however , the convergence radius of the series ( [ e1 ] ) is @xmath184 , so we can use the expansion directly in the case of the redshift being @xmath185 . by the numerical calculation , we find that @xmath186 corresponds to @xmath187 for the valuses of parameters @xmath139 and @xmath138 in the fig . [ 192clcontours3 ] . for the case of @xmath188 , we should use a direct analytic continuation . weierstrass @xcite had built the whole theory of analytic functions from the concept of power series . given a point @xmath189 ( @xmath190 ) , the function @xmath182 has a taylor expansion @xmath191.\ ] ] where the coefficients @xmath192 is still expressed as eq . ( [ e2 ] ) and @xmath193 can be decided by eq . ( [ e1 ] ) . the new series defines an analytic function @xmath194 which is said to be obtained from @xmath195 by direct analytic continuation . this process can be repeated any number of times . in the general case we have to consider a succession of power series @xmath195 , @xmath194, ... ,@xmath196 , each of which is a direct analytic continuation of the preceding one . by using this method we have the evolution of hubble parameter @xmath182 . furthermore , we have the function @xmath140 from eq . ( [ e3 ] ) . in fact , we need only to consider the case of @xmath197 for the essence supernovae data . we now apply the above described maximum likelihood method using the essence supernovae data which is one of the reliable published data set consisting of 192 sneia ( @xmath198 ) . beside the 162 data points given in table 9 of ref . @xcite , which contains 60 essence sneia , 57 snls sneia and 45 nearby sneia , we add 30 sneia detected at @xmath199 by the hubble space telescope @xcite as in ref.@xcite . in table [ differentvalues ] , we show the best fit of torsion parameters at different initial values of @xmath139 and @xmath138 . @l*15@l @xmath139 & @xmath138 & @xmath0 & @xmath32 + 0.25&0.35 & -0.10&1.44 + 0.20&0.34 & -0.08&1.80 + 0.15&0.34 & -0.06&2.40 + 0.10&0.33 & -0.04&3.60 + in fig . [ 192clcontours3 ] , contours with 68.3% , 95.4% and 99.7% confidence level are plotted , in which we take a marginalization over the model - independent parameter @xmath165 . the best fit as showed in the figure corresponds to @xmath200 and @xmath201 , and the minimum value of @xmath202 . for @xmath203 , one can get @xmath204 and the best fit @xmath205 . therefore , it s easy to know that @xmath206 is consistent at the @xmath207 level with the best fits of scalar torsion cosmology . in fig . [ zu ] , we show a comparison of the essence supernovae data along with the theoretically predicted curves in the context of scalar torsion and @xmath206 . we can see that the scalar torsion model(@xmath208 , @xmath209 , @xmath210 , @xmath211 ) gives a close curve behavior to the one from @xmath206 ( @xmath212 ) . clearly , the allowed ranges of the parameters @xmath0 and @xmath32 favor the case of @xmath213 if we chose @xmath214 and @xmath215 . with the essence supernovae data via the relation between the redshift @xmath141 and the distance modulus @xmath54 . the scalar torsion model(@xmath208 , @xmath209 , @xmath210 , @xmath211 ) gives a close curve behavior to the one from @xmath206 ( @xmath212).,title="fig:",width=264 ] with the essence supernovae data via the relation between the redshift @xmath141 and the distance modulus @xmath54 . the scalar torsion model(@xmath208 , @xmath209 , @xmath210 , @xmath211 ) gives a close curve behavior to the one from @xmath206 ( @xmath212).,title="fig:",width=272 ] and @xmath32 using the essence sneia dataset . here we have assumed @xmath216 , @xmath214 and @xmath215.,width=321 ] we have studied the statefinder diagnostic to the torsion cosmology , in which an accounting for the accelerated universe is considered in term of a riemann - cartan geometry : dynamic scalar torsion . we have shown that statefinder diagnostic has a direct bearing on the critical points . the statefinder diagnostic divides the torsion parameter @xmath0 into four ranges , which is in keeping with the requirement of dynamical analysis . therefore , the statefinder diagnostic can be used to an exceedingly general category of models including several for which the notion of equation of state is not directly applicable . the statefinder diagnostic has the advantage over the dynamical analysis at the simplicity , but the latter can provide more information . the most interesting characteristic of the trajectories is that there is a loop in the case of @xmath217 . this behavior corresponds to the heteroclinic orbit connecting the negative attractor and de sitter attractor . the trajectories with the shape of tadpole show that they pass through the @xmath69cdm fixed point along the time evolution , then the statefinder pairs are going along with a loop and they will pass through the @xmath69cdm fixed point again in the future . it is worth noting that there exists closed loop in the ref . @xcite , but there is no closed loop which contains the @xmath69cdm fixed point . these behaviors indicate that torsion cosmology is an elegant scheme and the scalar torsion mode is an interesting geometric quantity for physics . furthermore , the quasi - periodic feature of trajectories in the cases of @xmath76 or @xmath18 shows that the numerical solutions in ref . @xcite are not periodic , but are quasi - periodic near the focus for the coupled nonlinear equations . we fixed only the initial values , then fitted the torsion parameters to current sneia dataset . we find that the scalar torsion naturally explain the accelerating expansion of the universe for any torsion parameter @xmath0 . however , it is dependent @xmath0 and @xmath32 that there is a decelerating expansion before an accelerating expansion . the statefinder diagnostics show that the universe naturally have an accelerating expansion at late time and a decelerating expansion at early time for the case of @xmath218 and @xmath18 . if we refuse the possibility of non - positivity of the kinetic energy , we have to employ normal assumption ( @xmath17 ) . under this assumption , the effect of torsion can make the expansion rate oscillate . furthermore , with suitable adjustments of the torsion parameters and initial value , it is possible to change the quasi - period of expansion rate as well as its amplitudes . in order to have a quantitative understanding of the scalar torsion cosmology , the matter density @xmath219 , the effective mass density @xmath220 , and the quantity @xmath221 are important . this scenario bears a strong resemblance to the braneworld cosmology in a very different context by sahni , shtanov and viznyuk @xcite . the @xmath222 parameters in the torsion cosmology and in the @xmath69cdm cosmology can nevertheless be quite different . therefore , at high redshift , the torsion cosmology asymptotically expands like a matter - dominated universe with the value of @xmath222 inferred from the observations of the local matter density . at low redshift , the torsion model behaves like @xmath69cdm but with a renormalized value of @xmath223 . the difference between @xmath222 and @xmath223 is dependent on the present value of statefinder parameters @xmath224 . a more detailed estimate , however , lies beyond the scope of the present paper , and we will study it in a future work . finally , @xmath225 and @xmath226 should be extracted from some future astronomical observations in principle , especially the snap - type experiments . this work is supported by national science foundation of china grant no . 10847153 and no . 10671128 10 sahni v and starobinsky a 2000 _ int . _ d*9 * 373 [ astro - ph/9904398 ] + peebles p j e and ratra b 2003 _ rev . phys . _ * 75 * 559 [ astro - ph/0207347 ] + padmanabhan t 2003 _ phys . rept . _ * 380 * 235 [ hep - th/0212290 ] + copeland e j , sami m and tsujikawa s 2006 _ int . j. mod . _ d*15 * 1753 [ hep - th/0603057 ] + sahni v and starobinsky a 2006 _ int . j. mod _ d*15 * 2105 [ astro - ph/0610026 ] endo m and fukui t 1977 _ gen . * 8 * 833 + overduin j m and cooperstock f i 1998 _ phys . _ d*58 * 043506 [ astro - ph/9805260 ] + hao j g and li x z 2005 _ phys . _ b*606 * 7 [ astro - ph/0404154 ] + liu d j and li x z 2005 _ phys . _ b*611 * 8 [ astro - ph/0501596 ] + beesham a 1993 _ phys . rev _ d*48 * 3539 caldwell r r 2002 _ phys . lett . _ b*545 * 23 [ astro - ph/9908168 ] + sahni v and shtanov yu 2003 _ jcap _ * 11 * 014 [ astro - ph/0202346 ] + hao j g and li x z 2003 _ phys . _ d*67 * 107303 [ gr - qc/0302100 ] + liu d j and li x z 2003 _ phys . _ d*68 * 067301 [ hep - th/0307239 ] + li x z and hao j g 2004 _ phys . _ d*69 * 107303 [ hep - th/0303093 ] + hao j g and li x z 2003 _ phys . _ d*68 * 083514 [ hep - th/0306033 ] kerlick g d 1976 _ ann . phys . _ * 99 * 127 goenner h and mller - hoissen f 1984 _ class . grav . _ * 1 * 651 capozziello s , carloni s and troisi a 2003 _ recent res . astrophys . _ * 1 * 625 [ astro - ph/0303041 ] + boehmer c g and burnett j 2008 _ phys . _ d*78 * 104001 [ arxiv:0809.0469 [ gr - qc ] ] + boehmer c g 2005 _ acta phys . _ b**36 * * 2841 [ gr - qc/0506033 ] + mielke e w and romero e s 2006 _ phys . _ d*73 * 043521 + minkevich a v , garkin a s and kudin v i 2007 _ class . * 24 * 5835 [ arxiv:0706.1157 [ gr - qc ] shie k f , nester j m and yo h j 2008 _ phys . _ d*78 * 023522 [ arxiv:0805.3834 [ gr - qc ] ] + yo h j and nester j m 2007 _ mod . _ a*22 * 2057 [ astro - ph/0612738 ] + li x z , sun c b and xi p 2009 _ phys . _ d*79 * 027301 [ arxiv:0903.3088 [ gr - qc ] ] kopczyski w 1972 _ phys . _ a*39 * 219 nester j m and isenberg j a 1977 _ phys . _ d*15 * 2078 hecht r d , nester j m and zhytnikov v v 1996 _ phys . _ a*222 * 37 + yo h j and nester j m 1999 _ int _ d*8 * 459 [ gr - qc/9902032 ] shapiro i l 2002 _ phys . rep . _ * 357 * 113 [ hep - th/0103093 ] hao j g and li x z 2004 _ phys . _ d*70 * 043529 [ astro - ph/0309746 ] sahni v , saini t d , starobinsky a a and alam u 2003 _ jetp lett . _ * 77 * 201 [ astro - ph/0201498 ] alam u , sahni v and saini t d and starobinsky a a 2003 _ mon . not . soc . _ * 344 * 1057 [ astro - ph/0303009 ] zhang x 2007 _ jcap _ * 0703 * 007 [ gr - qc/0611084 ] + chang b , liu h , xu l , zhang c and ping y 2007 _ jcap _ * 0701 * 016 [ astro - ph/0612616 ] + liu d j and liu w z 2008 _ phys . _ d*77 * 027301 [ arxiv:0711.4854 [ astro - ph ] ] tretyakov p , toporensky a , shtanov y and sahni v 2006 _ class . * 23 * 3259 [ gr - qc/0510104 ] hoyel f , burbidge g and narlikar j v 1993 _ astrophys . j. _ * 410 * 437 [ astro - ph/9412045 ] hehl f w , mccrea j d , mielke e w and neeman y 1995 _ phys . rept . _ * 258 * 1 [ gr - qc/9402012 ] li x z , zhao y b and sun c b 2005 _ class _ * 22 * 3759 [ astro - ph/0508019 ] starobinsky a a 1998 _ jetp lett . _ * 68 * 757 [ astro - ph/9810431 ] + liu d j , sun c b and li x z 2006 _ phys . _ b*634 * 442 [ astro - ph/0512355 ] choudury t r and padmanabhan t 2005 _ astron . _ * 429 * 807 [ astro - ph/0311622 ] ahlfors v 1979 _ complex analysis _ ( new york : mcgraw hill ) wood - vasey w m et al . 2007 _ astrophys . j _ * 666 * 694 [ astro - ph/0701041 ] riess a g et al . 2007 _ astrophys . j _ * 659 * 98 [ astro - ph/0611572 ] davis t m et al . 2007 _ astrophys . j _ * 666 * 716 [ astro - ph/0701510 ] sahni v , shtanov y and viznyuk a 2005 _ j. cosmol . * 0512 * 005 [ astro - ph/0505004 ]

we apply the statefinder diagnostic to the torsion cosmology , in which an accounting for the accelerated universe is considered in term of a riemann - cartan geometry : dynamic scalar torsion . we find that there are some typical characteristic of the evolution of statefinder parameters for the torsion cosmology that can be distinguished from the other cosmological models . furthermore , we also show that statefinder diagnostic has a direct bearing on the critical points . the statefinder diagnostic divides the torsion parameter @xmath0 into differential ranges , which is in keeping with the requirement of dynamical analysis . in addition , we fit the scalar torsion model to essence supernovae data and give the best fit values of the model parameters .

SECTION 1. SHORT TITLE. This Act may be cited as the ``Cuban Humanitarian Trade Act of 2001''. SEC. 2. AMENDMENT TO EMBARGO AUTHORITY IN THE FOREIGN ASSISTANCE ACT OF 1961. Section 620(a)(1) of the Foreign Assistance Act of 1961 (22 U.S.C. 2370(a)(1)) is amended by striking the period at the end of the second sentence and inserting the following: ``, except that any such embargo shall not apply with respect to the export of any agricultural commodity, medicines, medical supplies, medical instruments, or medical equipment, or with respect to travel incident to the delivery of agricultural commodities, medicines, medical supplies, medical instruments, or medical equipment. As used in this paragraph, the terms `agricultural commodity' and `medicine' have the meanings given those terms in section 9 of the Cuban Humanitarian Trade Act of 2001.''. SEC. 3. LIMITATION ON EXISTING RESTRICTIONS ON TRADE WITH CUBA. Upon the enactment of this Act, any regulation, proclamation, or provision of law, including Presidential Proclamation 3447 of February 3, 1962, the Export Administration Regulations (15 CFR 730 and following), and the Cuban Assets Control Regulations (31 CFR 515), that prohibits exports to Cuba or transactions involving exports to Cuba and that is in effect on the date of the enactment of this Act, shall not apply with respect to the export to Cuba of agricultural commodities, medicines, medical supplies, medical instruments, or medical equipment, or with respect to travel incident to the delivery of agricultural commodities, medicines, medical supplies, medical instruments, or medical equipment. SEC. 4. LIMITATION ON THE FUTURE EXERCISE OF AUTHORITY. After the enactment of this Act, the President may not restrict the exportation to Cuba of agricultural commodities, medicines, medical supplies, medical instruments, or medical equipment-- (1) under the Export Administration Act of 1979, except to the extent such restrictions would be permitted under section 5 of that Act for goods containing parts or components on which export controls are in effect under that section; or (2) under section 203 of the International Emergency Economic Powers Act, except to the extent the authorities under that section are exercised to restrict the export of medical instruments or medical equipment to deal with a threat to the national security of the United States by virtue of the technology incorporated in such instruments or equipment. SEC. 5. OTHER PROVISIONS OF LAW; CONFORMING AMENDMENTS. (a) Trade Sanctions Reform and Export Enhancement Act of 2000.-- (1) Inapplicability.--The Trade Sanctions Reform and Export Enhancement Act of 2000 (title IX of H.R. 5426, as enacted into law by section 1(a) of Public Law 106-387, and as contained in the appendix of such Public Law) shall not apply with respect to exports to Cuba of agricultural commodities, medicines, medical supplies, medical instruments, or medical equipment. (2) Conforming amendments.--The Trade Sanctions Reform and Export Enhancement Act of 2000 is amended-- (A) in section 906(a)(1)-- (i) by striking ``to Cuba or''; and (ii) by inserting ``(other than Cuba)'' after ``to the government of a country''; (B) in section 908-- (i) by striking subsection (b); (ii) in subsection (a)-- (I) by striking ``Prohibition'' and all that follows through ``(1) In general.--'' and inserting ``In General.--''; (II) by striking ``for exports to Cuba or''; (III) by striking paragraph (2); and (IV) by redesignating paragraph (3) as subsection (b) (and conforming the margin accordingly); and (iii) in subsection (b) (as redesignated), by striking ``paragraph (1)'' and inserting ``subsection (a)''; (C) by striking section 910; and (D) by redesignating section 911 as section 910. (b) Sanctions Under Cuban Democracy Act of 1992.-- (1) Inapplicability.--Section 1706(b) of the Cuban Democracy Act of 1992 (22 U.S.C. 6005(b); prohibiting certain vessels from entering United States ports) shall not apply with respect to vessels that transport agricultural commodities, medicines, medical supplies, medical instruments, or medical equipment to Cuba, or that transport persons whose travel is incident to the delivery of agricultural commodities, medicines, medical supplies, medical instruments, or medical equipment to Cuba. (2) Conforming amendments.--(A) Section 1705 of the Cuban Democracy Act of 1992 (22 U.S.C. 6004) is amended-- (i) in subsection (b)-- (I) in the subsection caption by striking ``, Donations'' and inserting ``, Exports''; and (II) by striking ``donations of food to nongovernmental organizations or individuals in Cuba'' and inserting ``exports of agricultural commodities to Cuba''; (ii) by amending subsection (c) to read as follows: ``(c) Exports of Medicines and Medical Supplies to Cuba.--Exports of medicines, medical supplies, medical instruments, or medical equipment to Cuba shall not be restricted-- ``(1) except to the extent such restrictions would be permitted-- ``(A) under section 5 of the Export Administration Act of 1979 for goods containing parts or components on which export controls are in effect under that section; or ``(B) under clause (A), (B), or (C) of section 203(b)(2) of the International Emergency Economic Powers Act; ``(2) except in a case in which there is a reasonable likelihood that the item to be exported will be used for purposes of torture or other human rights abuses; ``(3) except in a case in which there is a reasonable likelihood that the item to be exported will be reexported; and ``(4) except in a case in which the item to be exported could be used in the production of any biotechnological product. Before imposing restrictions under this subsection, the President shall submit to the Congress a report describing the restrictions to be imposed and the reasons for the restrictions.''; and (iii) by striking subsection (d) and redesignating subsections (e), (f), and (g) as subsections (d), (e), and (f), respectively. (B) Section 1704(b)(2)(C)(i) of the Cuban Democracy Act of 1992 (22 U.S.C. 6003(b)(2)(C)(i)) is amended to read as follows: ``(i) exports of agricultural commodities to Cuba; or''. (C) Section 1704 of the Cuban Democracy Act of 1992 (22 U.S.C. 6003) is amended by adding at the end the following: ``(c) Definitions.--As used in this section and section 1705, the terms `agricultural commodity' and `medicine' have the meanings given those terms in section 9 of the Cuban Humanitarian Trade Act of 2001.''. SEC. 6. APPLICATION OF DENIAL OF FOREIGN TAX CREDIT WITH RESPECT TO CUBA. Subparagraph (A) of section 901(j)(2) of the Internal Revenue Code of 1986 (relating to denial of foreign tax credit, etc., with respect to certain foreign countries) is amended by adding at the end thereof the following new flush sentence: ``Notwithstanding the preceding sentence, this subsection shall not apply to Cuba with respect to income, war profits, or excess profits taxes paid to Cuba that are attributable to activities with respect to articles permitted to be exported to Cuba, or travel incident thereto that is permitted, by virtue of the enactment of the Cuban Humanitarian Trade Act of 2001. The preceding sentence shall apply after the date which is 60 days after the date of the enactment of this sentence.''. SEC. 7. PROHIBITION ON LIMITING ANNUAL REMITTANCES. (a) In General.--Except as provided in subsection (b), the Secretary of the Treasury may not limit the amount of remittances to Cuba that may be made by any person who is subject to the jurisdiction of the United States, and the Secretary shall rescind all regulations in effect on the date of enactment of this Act that so limit the amount of those remittances. (b) Statutory Construction.--Nothing in subsection (a) may be construed to prohibit the prosecution or conviction of any person committing an offense described in section 1956 of title 18, United States Code (relating to the laundering of monetary instruments) or section 1957 of such title (relating to engaging in monetary transactions in property derived from specific unlawful activity). SEC. 8. INAPPLICABILITY OF OTHER RESTRICTIONS. This Act and the amendments made by this Act apply notwithstanding section 102(h) of the Cuban Liberty and Democratic Solidarity (LIBERTAD) Act of 1996 (22 U.S.C. 6032(h)). SEC. 9. REPORT TO CONGRESS. Not later than 6 months after the date of the enactment of this Act, the President shall transmit to the Congress a report that sets forth-- (1) the extent (expressed in volume and dollar amounts) of sales to Cuba of agricultural commodities, medicines, medical supplies, medical instruments, and medical equipment, since the enactment of this Act; (2) a description of the types and end users of the goods so exported; and (3) whether there has been any indication that any medicines, medical supplies, medical instruments, or medical equipment exported to Cuba since the enactment of this Act-- (A) have been used for purposes of torture or other human rights abuses; (B) were reexported; or (C) were used in the production of any biotechnological product. SEC. 10. DEFINITIONS. In this Act: (1) Agricultural commodity.--The term ``agricultural commodity''-- (A) has the meaning given the term in section 102 of the Agricultural Trade Act of 1978 (7 U.S.C. 5602); and (B) includes fertilizer. (2) Medicine.--The term ``medicine'' has the meaning given the term ``drug'' in section 201 of the Federal Food, Drug, and Cosmetic Act (21 U.S.C. 7321).

Cuban Humanitarian Trade Act of 2001 - Amends the Foreign Assistance Act of 1961 to exempt from the embargo on trade with Cuba (including prohibitions under the Cuban Democracy Act of 1992 against the unloading at a U.S. port of vessels that previously entered a Cuban port to engage in trade) the export of any agricultural commodity (including fertilizer), medicines, medical supplies, medical instruments, or medical equipment, or any travel incident to delivery of such items. Exempts the same items from certain authorities limiting trade with Cuba, including the President's authority restricting exports to Cuba under the Export Administration Act of 1979 or the International Emergency Economic Powers Act.Amends the Trade Sanctions Reform and Export Enhancement Act of 2000 to repeal specified sections prohibiting: (1) U.S. Government assistance, including foreign and export assistance, U.S. credit or guarantees for exports to Cuba or for commercial exports to Iran, Libya, North Korea, or Sudan; and (2) the export of agricultural commodities (including the financing of their sale), medicine, or medical devices, and travel, to Cuba (effectively allowing the export of such commodities and travel to such country).Amends the Cuban Democracy Act of 1992 to exempt the export by a country of agricultural commodities to Cuba from the prohibition against U.S. assistance to any country that provides assistance to Cuba.Amends the Internal Revenue Code to terminate the denial of foreign tax credit with respect to income, war profits, or excess profits taxes paid to Cuba that are attributable to activities with respect to the permitted exports, or travel incident to such activities, under this Act.Prohibits the Secretary of the Treasury from limiting the amount of remittances to Cuba that any U.S. person may make. Declares that this prohibition does not prohibit the prosecution or conviction of any person committing a criminal offense relating to the laundering of money or engagement in monetary transactions in property derived from unlawful activities.

SECTION 1. SHORT TITLE. This Act may be cited as the ``Business Activity Tax Simplification Act of 2011''. SEC. 2. MODERNIZATION OF PUBLIC LAW 86-272. (a) Solicitations With Respect to Sales and Transactions of Other Than Tangible Personal Property.--Section 101 of the Act entitled ``An Act relating to the power of the States to impose net income taxes on income derived from interstate commerce, and authorizing studies by congressional committees of matters pertaining thereto'', approved September 14, 1959 (15 U.S.C. 381 et seq.), is amended-- (1) in section (a), by striking ``either, or both,'' and inserting ``any one or more''; (2) in subsection (a)(1), by striking ``by such person'' and all that follows and inserting ``(which are sent outside the State for approval or rejection) or customers by such person, or his representative, in such State for sales or transactions, which are-- ``(A) in the case of tangible personal property, filled by shipment or delivery from a point outside the State; and ``(B) in the case of all other forms of property, services, and other transactions, fulfilled or distributed from a point outside the State;''; (3) in subsection (a)(2), by striking the period at the end and inserting a semicolon; (4) in subsection (a), by adding at the end the following new paragraphs: ``(3) the furnishing of information to customers or affiliates in such State, or the coverage of events or other gathering of information in such State by such person, or his representative, which information is used or disseminated from a point outside the State; and ``(4) those business activities directly related to such person's potential or actual purchase of goods or services within the State if the final decision to purchase is made outside the State.''; (5) by striking subsection (c) and inserting the following new subsection: ``(c) For purposes of subsection (a) of this section, a person shall not be considered to have engaged in business activities within a State during any taxable year merely-- ``(1) by reason of sales or transactions in such State, the solicitation of orders for sales or transactions in such State, the furnishing of information to customers or affiliates in such State, or the coverage of events or other gathering of information in such State, on behalf of such person by one or more independent contractors; ``(2) by reason of the maintenance of an office in such State by one or more independent contractors whose activities on behalf of such person in such State are limited to making sales or fulfilling transactions, soliciting order for sales or transactions, the furnishing of information to customers or affiliates, and/or the coverage of events or other gathering of information; or ``(3) by reason of the furnishing of information to an independent contractor by such person ancillary to the solicitation of orders or transactions by the independent contractor on behalf of such person.''; and (6) in subsection (d)(1)-- (A) by inserting ``or fulfilling transactions'' after ``selling''; and (B) by striking ``the sale of, tangible personal property'' and inserting ``a sale or transaction, furnishing information, or covering events, or otherwise gathering information''. (b) Application of Prohibitions to Other Business Activity Taxes.-- Title I of the Act entitled ``An Act relating to the power of the States to impose net income taxes on income derived from interstate commerce, and authorizing studies by congressional committees of matters pertaining thereto'', approved September 14, 1959 (15 U.S.C. 381 et seq.), is amended by adding at the end the following: ``Sec. 105. For taxable periods beginning on or after January 1, 2012, the prohibitions of section 101 that apply with respect to net income taxes shall also apply with respect to each other business activity tax, as defined in section 5(a)(2) of the Business Activity Tax Simplification Act of 2011. A State or political subdivision thereof may not assess or collect any tax which by reason of this section the State or political subdivision may not impose.''. SEC. 3. MINIMUM JURISDICTIONAL STANDARD FOR STATE AND LOCAL NET INCOME TAXES AND OTHER BUSINESS ACTIVITY TAXES. (a) In General.--No taxing authority of a State shall have power to impose, assess, or collect a net income tax or other business activity tax on any person relating to such person's activities in interstate commerce unless such person has a physical presence in the State during the taxable period with respect to which the tax is imposed. (b) Requirements for Physical Presence.-- (1) In general.--For purposes of subsection (a), a person has a physical presence in a State only if such person's business activities in the State include any of the following during such person's taxable year: (A) Being an individual physically in the State, or assigning one or more employees to be in the State. (B) Using the services of an agent (excluding an employee) to establish or maintain the market in the State, if such agent does not perform business services in the State for any other person during such taxable year. (C) The leasing or owning of tangible personal property or of real property in the State. (2) De minimis physical presence.--For purposes of this section, the term ``physical presence'' shall not include-- (A) presence in a State for less than 15 days in a taxable year (or a greater number of days if provided by State law); or (B) presence in a State to conduct limited or transient business activity. (c) Taxable Periods Not Consisting of a Year.--If the taxable period for which the tax is imposed is not a year, then any requirements expressed in days for establishing physical presence under this Act shall be adjusted pro rata accordingly. (d) Minimum Jurisdictional Standard.--This section provides for minimum jurisdictional standards and shall not be construed to modify, affect, or supersede the authority of a State or any other provision of Federal law allowing persons to conduct greater activities without the imposition of tax jurisdiction. (e) Exceptions.-- (1) Domestic business entities and individuals domiciled in, or residents of, the state.--Subsection (a) does not apply with respect to-- (A) a person (other than an individual) that is incorporated or formed under the laws of the State (or domiciled in the State) in which the tax is imposed; or (B) an individual who is domiciled in, or a resident of, the State in which the tax is imposed. (2) Taxation of partners and similar persons.--This section shall not be construed to modify or affect any State business activity tax liability of an owner or beneficiary of an entity that is a partnership, an S corporation (as defined in section 1361 of the Internal Revenue Code of 1986), a limited liability company (classified as a partnership for Federal income tax purposes), a trust, an estate, or any other similar entity, if the entity has a physical presence in the State in which the tax is imposed. (3) Preservation of authority.--This section shall not be construed to modify, affect, or supersede the authority of a State to enact a law and bring an enforcement action under such law or existing law against a person or persons or an entity or entities, including but not limited to related persons or entities, that is or are engaged in an illegal activity, a sham transaction, or an actual abuse in its or their business activities in order to ensure a proper reflection of its or their tax liabilities, nor shall it supersede the authority of a State to require combined reporting. SEC. 4. GROUP RETURNS. If, in computing the net income tax or other business activity tax liability of a person for a taxable year, the net income or other economic results of affiliated persons is taken into account, the portion of such combined or consolidated net income or other economic results that may be subject to tax by the State shall be computed using the methodology that is generally applicable to businesses conducting similar business activities and, if that generally applicable methodology employs an apportionment formula, the denominator or denominators of that formula shall include the aggregate factors of all persons whose net income or other economic results are included in such combined or consolidated net income or other economic results and the numerator or numerators shall include the factors attributable to the state of only those persons that are themselves subject to taxation by the State pursuant to the provisions of this Act and subject to all other legal constraints on State taxation of interstate or foreign commerce. SEC. 5. DEFINITIONS AND EFFECTIVE DATE. (a) Definitions.--For purposes of this Act: (1) Net income tax.--The term ``net income tax'' has the meaning given that term for the purposes of the Act entitled ``An Act relating to the power of the States to impose net income taxes on income derived from interstate commerce, and authorizing studies by congressional committees of matters pertaining thereto'', approved September 14, 1959 (15 U.S.C. 381 et seq.). (2) Other business activity tax.-- (A) In general.--The term ``other business activity tax'' means any tax in the nature of a net income tax or tax measured by the amount of, or economic results of, business or related activity conducted in the State. (B) Exclusion.--The term ``other business activity tax'' does not include a sales tax, a use tax, or a similar transaction tax, imposed on the sale or acquisition of goods or services, whether or not denominated a tax imposed on the privilege of doing business. (3) Person.--The term ``person'' has the meaning given such term by section 1 of title 1 of the United States Code. Each corporation that is a member of a group of affiliated corporations, whether unitary or not, is itself a separate ``person.'' (4) State.--The term ``State'' means any of the several States, the District of Columbia, or any territory or possession of the United States, or any political subdivision of any of the foregoing. (5) Tangible personal property.--For purposes of section 3(b)(1)(C), the leasing or owning of tangible personal property does not include the leasing or licensing of computer software. (b) Effective Date.--This Act shall apply with respect to taxable periods beginning on or after January 1, 2012.

Business Activity Tax Simplification Act of 2011 - Expands the prohibition against state taxation of interstate commerce to include: (1) taxation of out-of-state sales transactions involving all forms of property, including intangible personal property and services (currently, only sales of tangible personal property are protected); and (2) all other business activity taxes in addition to net income taxes. Exempts from state taxation persons who enter a state merely to furnish information to customers and affiliates, to cover news or other events, or to gather information in the state. Sets forth jurisdictional standards for states in imposing, assessing, or collecting a net income tax or other business activity tax on interstate activities.  Defines "physical presence in a state" as: (1) being an individual physically in a state or assigning one or more employees to be in a state, (2) using the services of an agent to establish or maintain the market in a state, and (3) leasing or owning tangible personal or real property in a state (excluding the leasing or licensing of computer software).  Excludes from the definition of "physical presence" presence in a state for less than 15 days in a taxable year or presence in a state to conduct limited or transient business activity. Provides that this Act shall not be construed to modify or affect any state business activity tax on a partnership, an S corporation or limited liability company, or a trust or estate that has a physical presence in the state or to supersede the authority of a state to enact a law or bring a law enforcement action against persons or entities engaged in illegal activity or sham transactions. Sets forth a rule for computing the net income tax or other business activity tax liability of an affiliated group. Makes this Act applicable to taxable periods beginning on or after January 1, 2012.

SECTION 1. SHORT TITLE. This Act may be cited as the ``National Defense Oil Equity Act of 2003''. SEC. 2. FINDINGS. The Congress finds as follows: (1) Iraq has 112 billion barrels of proven oil reserves along with roughly 220 billion barrels of probable resources. Only Saudi Arabia's oil reserves are larger. By far, the majority of petroleum reserves (67%) are found in the Middle East. (2) The United States has 21 billion barrels of proven oil reserves, twelfth highest in the world. United States proven oil reserves have declined by almost 20% since 1990. (3) The United States consumes 25% of the world's oil supply, the largest share; yet it holds only 2.2 percent of the world's proven oil reserves. (4) Numerous foreign oil companies have preliminary contracts to spend billions of dollars developing Iraqi oil fields. These companies originate from Algeria, Australia, Britain, Canada, China, France, India, Indonesia, Italy, Japan, Malaysia, Netherlands, Russia, Spain, Turkey, and Vietnam. (5) According to several news accounts, the Administration is conferring with energy experts, industry executives, and Iraqi opposition leaders on how to revive and expand Iraq's oil fields after an invasion. (6) United States Special Forces have been on the ground inside Iraq since September of 2002 to monitor the oil fields and rigs. (7) During the first war in Iraq, oil prices rose to $41 per barrel, gasoline prices hit record levels, and oil companies made record profits. (8) According to Goldman Sachs, crude oil prices could reach $45 per barrel as a result of a war in Iraq. The price of oil has already increased $12 per barrel in the last year to $33 per barrel. SEC. 3. WINDFALL PROFITS TAX. (a) In General.--Subtitle E of the Internal Revenue Code of 1986 (relating to alcohol, tobacco, and certain other excise taxes) is amended by adding at the end thereof the following new chapter: ``CHAPTER 55--WINDFALL PROFIT ON CRUDE OIL AND PRODUCTS THEREOF ``Sec. 5886. Imposition of tax. ``SEC. 5886. IMPOSITION OF TAX. ``(a) In General.--In addition to any other tax imposed under this title, there is hereby imposed an excise tax on the sale in the United States of any crude oil or other taxable product a tax equal to the applicable percentage of the windfall profit on such sale. ``(b) Definitions.--For purposes of this section-- ``(1) Taxable product.--The term `taxable product' means any fuel which is a product of crude oil. ``(2) Windfall profit.--The term `windfall profit' means, with respect to any sale, so much of the profit on such sale as exceeds a reasonable profit. ``(3) Applicable percentage.--The term `applicable percentage' means-- ``(A) 50 percent to the extent that the profit on the sale exceeds 100 percent of the reasonable profit on the sale but does not exceed 102 percent of the reasonable profit on the sale, ``(B) 75 percent to the extent that the profit on the sale exceeds 102 percent of the reasonable profit on the sale but does not exceed 105 percent of the reasonable profit on the sale, and ``(C) 100 percent to the extent that the profit on the sale exceeds 105 percent of the reasonable profit on the sale. ``(4) Reasonable profit.--The term `reasonable profit' means the amount determined by the Reasonable Profits Board to be a reasonable profit on the sale. ``(c) Liability for Payment of Tax.--The taxes imposed by subsection (a) shall be paid by the seller. ``(d) Application of Section.--This section shall apply during the period beginning on the date of the enactment of this section and ending on the date that the President certifies to the Congress than no members of the Armed Forces of the United States are in Iraq.'' (b) Reasonable Profits Board.-- (1) Establishment.--There is established an independent board to be known as the ``Reasonable Profits Board'' (hereafter in this subsection referred to as the ``Board''). (2) Duties.--The Board shall make reasonable profit determinations for purposes of applying section 5886 of the Internal Revenue Code of 1986 (relating to windfall profit on crude oil, natural gas, and products thereof). (3) Advisory committee.--The Board shall be considered an advisory committee within the meaning of the Federal Advisory Committee Act (5 U.S.C. App.). (4) Appointment.-- (A) Members.--The Board shall be composed of 3 members appointed by the President of the United States. (B) Term.--Members of the Board shall be appointed for a term of 3 years. (C) Background.--The members shall have no financial interests in any of the businesses for which reasonable profits are determined by the Board. (5) Pay and travel expenses.-- (A) Pay.--Notwithstanding section 7 of the Federal Advisory Committee Act (5 U.S.C. App.), members of the Board shall be paid at a rate equal to the daily equivalent of the minimum annual rate of basic pay for level IV of the Executive Schedule under section 5315 of title 5, United States Code, for each day (including travel time) during which the member is engaged in the actual performance of duties vested in the Board. (B) Travel expenses.--Members shall receive travel expenses, including per diem in lieu of subsistence, in accordance with section 5702 and 5703 of title 5, United States Code. (6) Director of staff.-- (A) Qualifications.--The Board shall appoint a Director who has no financial interests in any of the businesses for which reasonable profits are determined by the Board. (B) Pay.--Notwithstanding section 7 of the Federal Advisory Committee Act (5 U.S.C. App.), the Director shall be paid at the rate of basic pay payable for level IV of the Executive Schedule under section 5315 of title 5, United States Code. (7) Staff.-- (A) Additional personnel.--The Director, with the approval of the Board, may appoint and fix the pay of additional personnel. (B) Appointments.--The Director may make such appointments without regard to the provisions of title 5, United States Code, governing appointments in the competitive service, and any personnel so appointed may be paid without regard to the provisions of chapter 51 and subchapter III of chapter 53 of that title relating to classification and General Schedule pay rates. (C) Detailees.--Upon the request of the Director, the head of any Federal department or agency may detail any of the personnel of that department or agency to the Board to assist the Board in accordance with an agreement entered into with the Board. (D) Assistance.--The Comptroller General of the United States may provide assistance, including the detailing of employees, to the Board in accordance with an agreement entered into with the Board. (8) Other authority.-- (A) Experts and consultants.--The Board may procure by contract, to the extent funds are available, the temporary or intermittent services of experts or consultants pursuant to section 3109 of title 5, United States Code. (B) Leasing.--The Board may lease space and acquire personal property to the extent that funds are available. (9) Funding.--There are authorized to be appropriated such funds as are necessary to carry out this subsection. (c) Clerical Amendment.--The table of chapters for subtitle E of such Code is amended by adding at the end the following new item: ``Chapter 55. Windfall profit on crude oil and refined petroleum products.'' (d) Effective Date.--The amendments made by this section shall take effect on the date of the enactment of this Act.

National Defense Oil Equity Act of 2003 - Amends the Internal Revenue Code to impose an excise tax on the sale of any crude oil or product of crude oil a tax equal to the applicable percentage of the windfall profit on such sale. Defines windfall profit to mean so much of the profit on such sale as exceeds a reasonable profit. Establishes the Reasonable Profits Board to make reasonable profit determinations.

SECTION 1. SHORT TITLE. This Act may be cited as the ``Carbon Monoxide Poisoning Prevention Act''. SEC. 2. FINDINGS. Congress finds the following: (1) Carbon monoxide is a colorless, odorless gas produced by burning any fuel. Exposure to unhealthy levels of carbon monoxide can lead to carbon monoxide poisoning, a serious health condition that could result in death. (2) Unintentional carbon monoxide poisoning from motor vehicles and the abnormal operation of fuel-burning appliances, such as furnaces, water heaters, portable generators, and stoves, in residential homes and other dwelling units kills more than 400 people each year and sends more than 20,000 to hospital emergency rooms for treatment. (3) Research shows that purchasing and installing carbon monoxide alarms close to the sleeping areas in residential homes and other dwelling units can help avoid fatalities. (4) Congress should promote the purchase and installation of carbon monoxide alarms in residential homes and dwelling units nationwide in order to promote the health and public safety of citizens throughout the Nation. SEC. 3. DEFINITIONS. For purposes of this Act, the following definitions apply: (1) The term ``approved carbon monoxide alarm'' means a carbon monoxide alarm that complies with the standards published, incorporated, or amended by the Commission with respect to such alarms pursuant to this Act. (2) The term ``carbon monoxide alarm'' means a device that detects carbon monoxide and sounds a distinctive audible alert before concentrations of carbon monoxide reach levels that would cause symptoms of carbon monoxide poisoning. (3) The term ``Commission'' means the Consumer Product Safety Commission. (4) The term ``dwelling unit'' means a room or suite of rooms used for human habitation, and includes a single family residence as well as each living unit of a multiple family residence (including apartment buildings) and each living unit in a mixed use building. (5) The term ``fire code enforcement officials'' means officials of the fire safety code enforcement agency of a State or local government. (6) The term ``NFPA 720'' means the Standard for the Installation of Carbon Monoxide Warning Equipment in Dwelling Units issued by the National Fire Protection Association in 2008, and any amended or similar successor standard pertaining to the proper installation of carbon monoxide alarms in dwelling units. SEC. 4. ADOPTION OF CONSUMER PRODUCT SAFETY RULES. (a) Mandatory Standards.--Notwithstanding any other provision of law, not later than 90 days after the date of enactment of this Act, the Commission shall publish in the Federal Register as mandatory consumer product safety standards the American National Standard for Single and Multiple Station Carbon Monoxide Alarms (ANSI/UL 2034) and the American National Standard for Gas and Vapor Detectors and Sensors (ANSI/UL 2075). Such mandatory consumer product safety standards shall take effect 180 days after they are published. (b) Revision of Standards.--Beginning 1 year after the date of enactment of this Act, if either standard described in subsection (a) is revised through the applicable consensus standards development process, Underwriters Laboratories shall notify the Commission of the revision and the revision shall be incorporated in the consumer product safety rule unless, within 60 days of such notice, the Commission determines that such revision does not carry out the purposes of this Act and publishes the basis for such a determination in the Federal Register. (c) Rulemaking.--Notwithstanding any other provision of this Act, the Commission may, at any time subsequent to publication of the consumer product safety standards required by subsection (a), initiate a rulemaking in accordance with section 553 of title 5, United States Code, to amend either standard to include any provision that the Commission determines is reasonably necessary to ensure the safe and effective operation of carbon monoxide alarms. (d) Treatment of Standards for Purposes of Enforcement.--For purposes of enforcement under the Consumer Product Safety Act, the standards published by the Commission pursuant to subsection (a), including any revision to such standards pursuant to subsection (b) or (c), shall be consumer product safety rules as defined in section 3(a)(6) of such Act (15 U.S.C. 2052(a)(6)). SEC. 5. REPORT TO CONGRESS. Not later than 1 year after the date of enactment of this Act, the Commission shall complete a study to evaluate whether requiring a language or languages in addition to English would improve the effectiveness of the label required of manufacturers of portable generators by the Commission under part 1407 of title 16, Code of Federal Regulations, to warn consumers of carbon monoxide hazards. SEC. 6. GRANT PROGRAM FOR CARBON MONOXIDE POISONING PREVENTION. (a) In General.--Subject to the availability of appropriations authorized by subsection (f), the Commission shall establish a grant program to provide assistance to eligible States and local governments to carry out the carbon monoxide poisoning prevention activities in subsection (d). (b) Eligibility.--To be eligible for a grant under the program, a State or local government shall-- (1) demonstrate to the satisfaction of the Commission that a State or local government has adopted a statute, or a State or local government agency has adopted a rule, regulation, or similar measure with the force and effect of law, requiring approved carbon monoxide alarms to be installed in accordance with NFPA 720 in dwelling units; and (2) submit an application to the Commission at such time, in such form, and containing such additional information as the Commission may require, which application may be filed on behalf of any qualified State or local government by the fire code enforcement officials for such State or local government. (c) Grant Amount; Priority.--The Commission shall determine the amount of the grants awarded under this section, and shall give priority to applications from States or local governments that-- (1) require approved carbon monoxide alarms to be installed in each existing dwelling unit-- (A) within which a fuel-burning appliance is installed, including a furnace, boiler, water heater, fireplace, or any other apparatus, appliance, or device that burns fuel; or (B) which has an attached garage; (2) propose to serve vulnerable populations such as children, the elderly, or low-income households; and (3) demonstrate greater than average losses of life from carbon monoxide poisoning in the home. (d) Use of Funds.--A State receiving a grant under this section may use grant funds-- (1) to purchase and install approved carbon monoxide alarms in the dwelling units of low-income families or elderly persons, facilities that commonly serve children or the elderly, including childcare facilities, public schools, and senior centers, or student dwelling units owned by public universities; (2) to train State or local fire code enforcement officials in the proper enforcement of State or local laws concerning approved carbon monoxide alarms and the installation of such alarms in accordance with NFPA 720; (3) for the development and dissemination of training materials, instructors, and any other costs related to the training sessions authorized by this subsection; and (4) to educate the public about the risk associated with carbon monoxide as a poison and the importance of proper carbon monoxide alarm use. (e) Limitation on Use of Funds.-- (1) Administrative costs.--No more than 10 percent of any grant funds may be used to cover administrative costs not directly related to training described in paragraph (2) of subsection (d). (2) Public outreach.--No more than 25 percent of any grant may be used to cover costs of activities described in paragraph (4) of subsection (d). (f) Authorization of Appropriations.--There are authorized to be appropriated to the Commission $2,000,000 for each of fiscal years 2011 through 2015 to carry out this Act, such sums to remain available until expended. Any amounts appropriated pursuant to this paragraph that remain unexpended and unobligated at the end of fiscal year 2015 shall be retained by the Commission and credited to the appropriations account that funds enforcement of the Consumer Product Safety Act. (g) Commission Report.--Not later than 1 year after the last day of each fiscal year for which grants are made under this section, the Commission shall submit to Congress a report evaluating the implementation of the grant program authorized by this section. Passed the House of Representatives July 28, 2010. Attest: LORRAINE C. MILLER, Clerk.

Carbon Monoxide Poisoning Prevention Act - Amends the Consumer Product Safety Act (the Act) to require the Consumer Product Safety Commission (CPSC) to publish the American National Standard for Single and Multiple Station Carbon Monoxide Alarms (American National Standard ANSI/UL 2034) and the American National Standard for Gas and Vapor Detectors and Sensors (ANSI/UL 2075) as mandatory consumer product safety standards. Requires the Underwriters Laboratories to notify the CPSC when either such standard is revised and to incorporate the revision in the consumer product safety rule, unless the CPSC determines that such revision does not carry out the purposes of this Act. Allows the CPSC, at any time subsequent to publication of such consumer product safety standards, to initiate a rulemaking to amend either standard to include any provision determined necessary to ensure the safe and effective operation of carbon monoxide alarms. Treats the national standards published by the CPSC pursuant to this Act, including any revision, as consumer product safety rules for purposes of enforcement under the Act. Requires the CPSC to evaluate whether requiring a language or languages in addition to English would improve the effectiveness of the label required to warn consumers of carbon monoxide hazards. Requires the CPSC to establish a grant program to provide assistance to eligible states and local governments to carry out carbon monoxide prevention activities, including activities for: (1) the purchase and installation of approved carbon monoxide alarms in the dwelling units of low-income families or elderly persons, facilities that commonly serve children or the elderly, or student dwelling units owned by public universities; (2) training state or local fire officials in the proper enforcement of state or local laws concerning such alarms and their installation; and (3) educating the public about the risk associated with carbon monoxide as a poison and the importance of proper carbon monoxide alarm use. Sets limitations on the use of grant funds for: (1) administrative costs not directly related to such training of state and local fire officials; and (2) the costs of the activities of such public outreach. Gives priority to applications from states or local governments that: (1) require the installation of approved carbon monoxide alarms in existing dwelling units within which a fuel-burning appliance, apparatus, or device is installed or which has an attached garage; (2) propose to serve vulnerable populations; and (3) have greater than average losses of life from carbon monixide poisoning in the home. Authorizes appropriations through FY2015 to the CPSC to carry out this Act. Requires the CPSC to report on the implementation of the grant program authorized by this Act.

in the management of cervical cancer with definitive radiation therapy , brachytherapy plays a central role because it has intrinsic physical property of steep dose gradient and has a potential to deliver relatively large dose while sparing the surrounding organ at risk ( oar ) as low as possible [ 1 , 2 ] . small tumors , which are within isodose line generated by conventional intracavitary brachytherapy ( icbt ) , consisted of intrauterine ( tandem ) and vaginal ( ovoid / ring ) sources , calculated based on the traditional manchester principles [ 3 , 4 ] , can be well controlled . tumors , which are slightly larger than isodose volume created by icbt , can be well treated by image - guided adaptive brachytherapy ( igabt ) [ 5 , 6 , 7 , 8 ] with or without additional interstitial needle insertion ( hybrid brachytherapy hbt ) [ 9 , 10 , 11 , 12 ] . on the other hand , guidelines from the american brachytherapy society recommends high - dose - rate ( hdr ) interstitial brachytherapy ( isbt ) for cervical cancer patients in certain clinical situations such as bulky lesions , a narrow vaginal apex , inability to enter the cervical os , extension to the lateral parametria or pelvic sidewall , and lower vaginal extension . in isbt , multiple applicators insertion is required and it is more invasive compared to icbt or hbt technique with patients laid on bed overnight with the applicators in place during treatment period . however , a certain groups of patients exists whose tumors are too large to be well covered by icbt or hbt . in this study , consecutive uterine cervical patients in our department treated by primary radiation therapy including brachytherapy were overviewed and the role of isbt was explored . principles of management for locally advanced uterine cervical cancer in our institution were described in our previous report . if patients were under 75 years old and had adequate organ function , concurrent chemoradiation therapy with weekly cisplatin ( 40 mg / m / week ) was delivered by 3d conformal 4-fields box technique with 15 mv linear accelerator ( clinac ix , varian medical system , palo alto , ca , usa ) . the common ebrt fields included whole uterus , parametrium , upper part of vagina down to the level of lower border of the obturator foramens , and the draining pelvic lymph nodes up to the level of the common iliac ( l4/5 junction ) . the subclinical regional lymph node clinical target volume ( ctv ) was contoured according to the guideline . if the primary lesion involved lower third of vagina or there were clinically palpable metastatic inguinal lymph nodes , inguinal regions were also included in ebrt portals . during radiation therapy , tumor response was assessed weekly by an attending radiation oncologist through gynecological examination . to lower the rectum and the bladder dose , 4 cm - width of central shield ( cs ) was inserted after 30 - 40 gy of whole pelvic radiation therapy ( wprt ) . the initiation of cs depends upon the tumor shrinkage according to japan society of gynecologic oncology guidelines . in cases with poor tumor response against ebrt , all brachytherapy was carried out by ir remote after loading system ( rals , microselectron hdr , nucletron , veennendaal , the netherlands ) . from 2008 , computed tomography ( ct)-based image - guided icbt for uterine cervical cancer patients was started in our department , and ct - based image - guided hdr - isbt was started in the same year . hybrid brachytherapy has started from 2010 for tumors with mild to moderate parametrial invasion that could not be adequately covered with icbt [ 16 , 17 ] . the detailed procedure of hdr - isbt for patients with cervical cancer was described in our previous studies [ 18 , 19 , 20 ] . in brief , transperineal needle applicators were inserted under either the combination of general and epidural , or the combination of local anesthesia and sedation with the patients in lithotomy position . simulation ct was carried out by large - bore ct ( aquilion lg , toshiba , tokyo , japan ) , which could take images with patients lying in the lithotomy position with applicators in place without moving patients . the image - guided brachytherapy planning was performed based on those ct images with slice interval of 2 mm . treatment planning was done with a brachytherapy planning system ( oncentra nucletron , veenendaal , the netherlands ) . the syed - neblett perineal template ( best medical international , inc . , springfield , va , usa ) was used because it has an advantage of ensuring parallelism and stability of applicator needles throughout the treatment period . a few titanium seed markers were inserted into the target and these markers were used as a reference for daily correction of needle deviation . the ctv was defined based on the ct image taken after needle insertion with patients in the lithotomy position . information obtained from gynecological examination performed immediately before needle insertion , intra - operative trus images , and the most recent magnetic resonance images ( mris ) , which were taken in majority of cases , were also taken into consideration for ctv determination . reference points were set on the surface of the ctv and the prescribed dose was delivered to those points . dose calculation was performed by geometrical optimization or dose point volume optimization , followed by manual graphical modification to cover the ctv with the prescription dose while keeping the dose to oar to a minimum . hyper - dose sleeve , which represents 200% of prescribed dose of a certain applicator should not fuse to that of another applicator in order not to increase the high dose volume . the dose constraint of combining dose of wprt and hdr - isbt for the rectum and the bladder d2cc was 75 gy and 90 gy ( eqd2 , / = 3 gy ) , respectively . our previous study found that vaginal d2cc greater than 145 gy ( eqd2 , / = 3 gy ) was associated with increased risk of developing late vaginal ulcer development , therefore , dose constraint for vagina was set under 145 gy . although no specific dose constraint was set to urethra , urethral catheter was inserted in all cases and it was easy to visualize the urethra , attention was paid not to deliver large dose to urethra . the prescription dose per fraction of hbr - isbt at our department is 6 gy . in a whole treatment session , needle insertion was performed once and irradiation was conducted twice daily at 6-hour interval with patients kept in bed overnight throughout the treatment period . figure 1 shows an example of dose distribution of ct - based image - guided hdr - isbt . an example of dose distribution of computed tomography based image - guided high - dose - rate interstitial brachytherapy and pictures of perineal needle insertion through syed - neblette template when calculating the combined dose of ebrt and hdr - isbt , the equivalent dose in 2 gy fractions ( eqd2 ) was utilized according to the linear - quadratic dose - effect model [ 22 , 23 , 24 ] . for calculating tumor and oar doses , / was assumed as 10 gy and 3 gy , respectively . dose contribution from cs the minimum dose covering 90% of the ctv ( ctv d90 ) in eqd2 was used as the representative dose of hdr - isbt . patients with histologically proven cervical squamous cell carcinoma , adenocarcinoma , or adenosquamous carcinoma , who were treated by primary radiation therapy including hdr - isbt with a minimum follow - up period of 24 months were included in this study . patients with distant metastasis , except para - aortic lymph node ( paln ) , were excluded from this study . survival time was calculated from the start of the radiation therapy until the last follow - up attendance or death from any cause . the local control rate ( lc ) was calculated from the start of the radiation therapy and histological or apparent radiological evidence of pelvic disease recurrence within the radiation field , which was considered to be an event and was censored at the time of death , non - local relapse , or last follow - up visit . progression - free survival ( pfs ) was calculated from the start of the radiation therapy until the last follow - up attendance or any recurrence of the disease . the cumulative overall survival ( os ) and this retrospective study was approved by the institutional ethical review board of the national cancer center hospital ( approval number : 2015 - 359 ) and was performed in accordance with the ethical standards laid down in the 1964 declaration of helsinki and its later amendments . consolidated standards of reporting trials ( consort ) flow diagram is shown in figure 2 . from december 2008 to october 2014 , 209 consecutive uterine cervical cancer patients were treated with primary radiation therapy . among them , 142 and 42 patients were treated by icbt and hbt , respectively . therefore , these 184 patients were excluded from this study and remaining 25 patients ( 12% ) were treated by hdr - isbt . patients who had distant metastasis other than paln were further excluded from the study , therefore , 5 patients were excluded and a total of 20 patients consisted of this analysis . in figure 3 , the reasons for having chosen isbt are shown . consolidated standards of reporting trials ( consort ) flow diagram of uterine cervical patients treated as primary radiation therapy from december 2008 to october 2014 in our hospital venn diagram showing reasons for selecting computed tomography based image - guided high - dose - rate interstitial brachytherapy table 1 demonstrates patients and tumor characteristics . as many as 7 patients had radiologically evident paln metastasis at the time of presentation . all the patients received higher than 30 gy of wprt before delivery of isbt , and median wprt dose was 40 gy . median size of hr - ctv measured by ct taken after needle insertion was 115.5 ml ( range 6.6175.6 ml ) , and median hr - ctv d90 in eqd2 was 74.2 gy ( 60.488.5 gy ) . because radioactivity of iridium source varies from time to time , percentage of interstitial component was calculated by dividing sum of dwell time of all interstitial needles with total treatment time . patients who received supra - vaginal hysterectomy for uterine myoma ( n = 3 ) were excluded from this calculation , because no tandem was inserted in those patients . patients and disease characteristics ( n = 20 ) treatment details ( n = 20 ) ratio of dwell time of all intersititial needles divided by total treatment time . patients who received supra - vaginal hysterectomy for uterine myoma ( n = 3 ) were excluded from the analysis because no tandem was inserted in those patients . median follow - up period for patients still alive at last contact was 32.0 months ( range 27.067.2 months ) . three - year os , pfs , and lc were 44.4% , 38.9% , and 87.8% , respectively ( figure 4 ) . at the time of analysis , seven patients were alive without disease relapse , while eleven patients died because of progression of cervical cancer , and one due to other reasons without any evidence of disease progression . clinical factors were compared between patients with or without disease progression or local relapse by univariate analysis ( tables 3 and 4 ) . patients with local relapse had significantly higher ratio of hydronephrosis and lower hemoglobin value at initial presentation ( p = 0.032 and p = 0.032 , respectively ) . potential predictors influencing disease progression potential predictors influencing local relapse kaplan meier survival curves for local control ( lc ) , progression - free survival ( pfs ) , and overall survival ( os ) of uterine cervical cancer patients without distant metastasis other than para - aortic lymph nodes treated by computed tomography based image - guided high - dose - rate interstitial brachytherapy venn diagram showing patterns of first relapse after computed tomography based image - guided high - dose - rate interstitial brachytherapy one patient experienced grade 3 rectal bleeding requiring hospitalization and blood infusion , although the rectum d2cc of this patient was 61.5 gy . this patient underwent intra - arterial infusion of chemotherapy despite of no evidence of disease progression at the primary hospital after receiving hdr - isbt . therefore , it can be assumed that such intra - arterial treatment , which has influence on circulation of normal tissue , would have altered surrounding environment . four patients experienced grade 2 rectal bleeding , one grade 2 cystitis , and two grade 2 vaginal ulcer . one patient experienced grade 3 rectal bleeding requiring hospitalization and blood infusion , although the rectum d2cc of this patient was 61.5 gy . this patient underwent intra - arterial infusion of chemotherapy despite of no evidence of disease progression at the primary hospital after receiving hdr - isbt . therefore , it can be assumed that such intra - arterial treatment , which has influence on circulation of normal tissue , would have altered surrounding environment . four patients experienced grade 2 rectal bleeding , one grade 2 cystitis , and two grade 2 vaginal ulcer . interstitial brachytherapy with transperineal approach in locally advanced cervical cancer is a well - established method for decades and there are numerous studies on isbt ; the vast majority of them are from 2d era [ 25 , 26 , 27 , 28 ] . however , there is also an increasing number of studies based on 3d image - based brachytherapy [ 19 , 20 , 29 , 30 , 31 ] . most of the reports of isbt focused only on patients treated with isbt , but current study overlooked all cervical cancer patients in a single institution who were treated by brachytherapy including icbt , hbt , and isbt , and reported the proportion of patients treated by isbt . it has been shown from several reports that most of the tumors can be treated with icbt or hbt . nevertheless , there still exists a small group of patients whose tumors require isbt to achieve better local control at a cost of its invasiveness . in current study , 12% of uterine cervical patients who were treated with primary radiation therapy received hdr - isbt . compared with recently published retro embrace study , a multicenter cohort study that reported clinical outcome of image - guided brachytherapy in locally advanced cervical cancer , this number is relatively high . in the retro embrace study , median tumor width at diagnosis was 5 cm and 168 out of 731 patients ( 23.0% ) were treated with hbt . one of the reasons why so many patients were treated with isbt in our institution was that , because there are only few institutions in our country capable to perform isbt , and such patients who could not be well - treated with conventional icbt were referred to our institution . compared to treatment schedule without using cs , brachytherapy starts earlier before any considerable tumor shrinkage from proceeding pelvic ebrt is allowed . local control after hdr - isbt was favorable despite having several adverse clinical factors such as large tumor size or advanced stage ( table 1 ) . however , in current study , distant metastases were frequently observed , suggesting that microscopic distant metastasis would supposedly have existed at initial presentation . currently , outback trial is under way , which tests the superiority of adjuvant chemotherapy after ccrt over ccrt alone for locally advanced uterine cervical cancer patients . if the result of this trial will be positive , it is possible that adjuvant chemotherapy would be beneficial for patients whose primary tumor require hdr - isbt . median hr - ctv d90 in eqd2 was 74.2 gy and it was lower than 87 gy , which was recommended prescribed dose for hr - ctv proposed by dimopoulos et al . and abs guidelines [ 1 , 2 , 7 ] . however , 74.2 gy was calculated by simply adding the dose from wprt and isbt , and dose contribution from cs , which is utilized to minimize dose delivered to the rectum or the bladder neck , was not taken into account according to japan society of gynecologic oncology guideline . calculated total dose delivered to hr - ctv including dose from cs using deformable image registration technique , and reported that actual dose delivered to hr - ctv was higher than simple summation of wprt and isbt . although , deformable image registration technique has its own limitation , the anatomical relationship would change dramatically with the applicators in place compared with the ebrt situation . additionally , in our treatment strategy , timing of delivering brachytherapy is earlier than that of treatment schedule without using cs . in the treatment schedule , in which no cs is applied in contrast , in a treatment schedule with cs , brachytherapy is started after initiation of cs . therefore , overall treatment time is much shorter in treatment schedule with cs than that of without cs . showed the efficacy of treatment schedule with cs in a series of multicenter prospective clinical trials [ 35 , 36 ] , and our group demonstrated favorable results with schedule with cs in ct based 3d image - guided brachytherapy . hybrid brachytherapy is much easier to perform compared with isbt because it only requires a few interstitial needles and could be performed in outpatient setting . in contrast , isbt demands time and labor , and forces the patients to lay on the bed overnight during treatment period . therefore , it is important to build a national system , in which patients who require isbt could be referred to high - volume centers efficiently . current matter in question is that there exist no concrete guidelines for selecting icbt , hbt , or isbt for locally advanced uterine cervical cancer . recently published simulation analysis and they proposed tumors that was larger than 5 4 4 cm were treated by isbt . because they used simple rectangular imaginary tumor for their analysis , the results should be interpreted with caution . there were several limitations in our study that was a retrospective study from a single institution with a quite limited number of patients . because of the limited number of patients , any analytical results derived from this study should be interpreted with a caution . a prospective trial is warranted to validate the superiority of isbt over other types of brachytherapy methods in locally advanced uterine cervical cancer patients . feasibility and favorable local control of interstitial brachytherapy for locally advanced cervical cancer was demonstrated through a single institutional experience with a small number of patients .

purposethe aim of this study was to report the clinical results of uterine cervical cancer patients treated by primary radiation therapy including brachytherapy , and investigate the role of interstitial brachytherapy ( isbt).material and methodsall consecutive uterine cervical cancer patients who were treated by primary radiation therapy were reviewed , and those who were treated by isbt were further investigated for clinical outcomes and related toxicities.resultsfrom december 2008 to october 2014 , 209 consecutive uterine cervical cancer patients were treated with primary radiation therapy . among them , 142 and 42 patients were treated by intracavitary and hybrid brachytherapy , respectively . twenty - five patients ( 12% ) were treated by high - dose - rate ( hdr)-isbt . five patients with distant metastasis other than para - aortic lymph node were excluded , and 20 patients consisted of the analysis . three - year overall survival ( os ) , progression - free survival ( pfs ) , and local control ( lc ) rate were 44.4% , 38.9% , and 87.8% , respectively . distant metastasis was the most frequent site of first relapse after hdr - isbt . one and four patients experienced grade 3 and 2 rectal bleeding , one grade 2 cystitis , and two grade 2 vaginal ulcer.conclusionsfeasibility and favorable local control of interstitial brachytherapy for locally advanced cervical cancer was demonstrated through a single institutional experience with a small number of patients .

microglia are derived from myeloid precursor cells in the periphery and penetrate the central nervous system ( cns ) during embryogenesis . they account for approximately 1020% of all cells in the cns , however their distribution varies from one region to another [ 2 , 3 ] . microglial density is particularly high in the hippocampus , basal ganglia , substantia nigra , and spinal cord [ 2 , 4 ] . microglia are regarded as the resident macrophages in the cns and , similar to peripheral macrophages , they display different morphology depending upon their physiological states . in the resting physiological state , microglial cells are ramified with slender , radially projecting processes with similar thickness , length , and ramification , whereas in pathological states , microglia can be activated presenting an amoeboid morphology characterized by large soma , short / thick , and radially projecting processes with few ramifications [ 46 ] . although most studies have focused on the role of activated microglia and synaptic transmission , both resting and activated microglia dynamically interact with synapses shaping their connectivity and function . microglial processes constantly and dynamically survey their environment and interact with nearby synapses [ 8 , 9 ] . in mature cns , it has been observed that microglial processes interact with axon terminals and dendritic spines in a transient manner , for an average of five minutes and at a rate of approximately one microglial contact per hour . notably , microglia processes are driven by neuronal activity and can simultaneously interact with both presynaptic and postsynaptic elements . reducing neural activity by inhibiting sensory inputs or lowering body temperature results in retraction of microglial processes and decreases the frequency of contacts between microglial processes and synapses . it is well known that astrocyte processes envelop synapses and actively modulate physiological synaptic transmission ; however , whether and how microglia directly influence physiological synaptic transmission is still unclear . several studies demonstrated that microglial processes can engulf synapses and participate to their phagocytic elimination in an experience - dependent manner in the mature healthy brain [ 1113 ] . interestingly , a progressive accumulation of microglial phagocytic - like structures was observed in both mouse visual and auditory cortices by age - related loss of vision and hearing , respectively . this suggests that microglia shape neuronal circuits not only during postnatal development but aslo along the lifespan . together , these observations suggest that periodic interactions between microglia and synapses exist in the absence of pathological insult . these interactions may be compromised following nervous system injury or disease . the physiological role of microglia in spinal cord circuitry development and pain transmission remains to be investigated . our bodies play host to a wide variety of sensory information that is detected every moment by the peripheral nervous system . primary sensory neurons that are responsible for the detection and transduction of painful stimuli ( e.g. , cold , heat , mechanical , and chemical ) , which are somatosensory stimuli that cause potential danger to the organism , are called nociceptors . nociception is of vital importance for survival ; thus , it has become a highly regulated pathway within the nervous system of humans . persistent nociceptive input in this system after intense noxious stimulation or tissue injury results in activity - dependent plasticity or a progressive increase in the response of the system to repeated stimuli . as a result of the neural plasticity , a normally innocuous low - threshold stimulation such as light touch could trigger a painful response ( mechanical allodynia ) . pathological pain or chronic pain results from neural plasticity both in the peripheral nervous system ( i.e. , peripheral sensitization ) and cns ( central sensitization ) . the circuitry in the spinal cord dorsal horn connects incoming primary afferents to outgoing projection neurons that ascend to the brain . the projection neurons in the superficial dorsal horn ( lamina i ) also receive input from interneurons in the lamina ii . importantly , spinal cord dorsal horn neurons undergo marked plastic changes in the pathological conditions , leading to hyperactivity of the projections neurons . thus , dorsal horn is not only a critical relay center in nociceptive transmission but also an important player in the development and maintenance of central sensitization [ 16 , 17 ] . several animal models are used for the study of neuropathic pain . in chronic constriction injury ( cci ) , the sciatic nerve is constricted by several loose ligatures . in spared nerve injury ( sni ) , the tibial and common peroneal divisions of the sciatic nerve are ligated and cut while sparing the sural division . in spinal nerve ligation ( snl ) , a spinal nerve , usually l5 , each of these models produces robust mechanical allodynia for weeks following injury ; however , the underlying mechanisms may vary . here we will focus on the contribution of spinal cord microglia to central sensitization in nerve injury - induced neuropathic pain and tissue injury - induced inflammatory pain states . under pathological conditions , especially nerve injury conditions , microglia undergo microgliosis , a complex set of changes that allow the cell to respond rapidly and perform a broad range of functions such as shielding injury sites , phagocytosing cellular debris , and releasing inflammatory signals to initiate and/or propagate the immune response . traditionally , microgliosis has been determined by a change in morphology from ramified to amoeboid . several pain models of persistent neuropathic pain including cci , sni , snl , or spinal cord injury as well as chronic morphine - induced hyperalgesia and tolerance are associated with the development of microgliosis in the dorsal horn of the spinal cord [ 2123 ] . figure 1 shows microglial reaction in the dorsal horn of the lumbar spinal cord seven days following cci of the sciatic nerve in cx3cr1-gfp mice . gfp expression revealed evenly distributed resident microglia in the contralateral side of the spinal cord that exhibited a quiescent or resting type morphology ( left , figure 1 ) . however on the side ipsilateral to injury ( right , figure 1 ) , microglia of the dorsal horn and ventral horn showed enlarged and amoeboid morphology , indicating their activation . nerve injury also induces marked increases in the density and number of microglia , due to proliferation and possible migration ( figure 1 ) . of interest , nerve injury - induced microgliosis is very mild in young animals ( 2 - 3 weeks old ) . it should be noted , however , that there are also a number of persistent pain conditions that are not associated with spinal cord microgliosis , such as adjuvant - induced inflammatory pain and chemotherapy - induced neuropathic pain [ 27 , 28 ] . mitogen - activated kinase ( mapk ) pathways are important for intracellular signal transduction and play critical roles in neuronal plasticity and inflammatory responses . the mapk family consists of three separate signaling pathways : extracellular signal - regulated kinases ( erk ) , p38 , and c - jun n - terminal kinase ( jnk ) . mapk activation is correlated with most if not all persistent pain conditions [ 29 , 30 ] . several neuropathic pain models , including spinal nerve injury and spared nerve injury , exhibit a robust increase in p38 activation ( phosphorylation ) in microglia of the dorsal horn beginning at twelve hours , peaking at three days , and slowly declining over several weeks [ 29 , 3133 ] . intrathecal administration of p38 inhibitors has been shown to attenuate neuropathic pain [ 29 , 33 ] . minocycline , a broad - spectrum antimicrobial tetracycline compound that inhibits microglial activation , also decreases pain behavior following nerve injury [ 34 , 35 ] , possibly by inhibiting p38 activation . however , minocycline is not able to reverse existing pain states . interestingly , intrathecal administration of minocycline in models of inflammatory pain , where morphological activation of microglia is not evident , also prevents the development of mechanical sensitization , by inhibiting spinal cord microglial p38 activation [ 37 , 38 ] . the morphological changes associated with microgliosis may be mediated by the activation of erk / mapk , and nerve injury was shown to induce erk activation in spinal microglia in the early phase . it seems there may be multiple activation states whereby microglia do change the manner with which they participate in neural plastic changes , but do not reach a morphologically activated phenotype . the p38 mapk pathway can be activated by a host of molecules known to increase pain sensitivity , including the proinflammatory cytokines tnf and il-1 , ccl2 ( also known as monocyte chemoattractant protein 1 ( mcp-1 ) ) , fractalkine ( cx3cl1 ) , inducible nitric oxide synthase ( inos ) , and matrix metalloprotease-9 ( mmp-9 ) as well as the atp receptors p2x4 and p2x7 [ 4047 ] . as shown in figure 2 , some of these microglial activators , such as atp , ccl2 , fractalkine , and mmp-9 , could be released from primary afferent neurons [ 48 , 49 ] . once activated , the p38 pathway induces the expression of proinflammatory transcription factors , enzymes , and signaling molecules , including nfkappab , cox2 , inos , bdnf , tnf , il-1 , and il-6 [ 38 , 41 , 50 ] . p38 activation in microglia also results in increased release of bdnf and tnf in microglia . microglial production of proinflammatory cytokines can further recruit microglia , activate surrounding astrocytes , and promote the sensitization of central nervous system nociceptive circuits . the development of central sensitization in persistent pain is characterized by increased excitatory synaptic transmission and decreased inhibitory synaptic transmission in the dorsal horn of the spinal cord . in order to modulate pain sensitivity and participate in central sensitization , while neurotransmitters such as glutamate , gaba , and glycine produce synaptic effects at m concentrations , glial cytokines , chemokines , and growth factors can affect synaptic activity at nm concentrations [ 5153 ] . accumulating evidence indicates a critical role of tnf , il-1 , and bdnf , all of which are released from activated microglia , in inducing the hyperactivity of dorsal horn neurons and thus in the development of pain hypersensitivity primarily in the setting of neuropathic pain , through modulation of both excitatory and inhibitory neurotransmission in the dorsal horn [ 40 , 54 , 55 ] . tnf is known to play a role in synaptic plasticity , which has been studied mainly in hippocampal slices . glial tnf has been shown to enhance synaptic efficacy by increasing the surface expression of glur1-possessing ampa receptors via tnfr1-mediated pi3 k activation [ 56 , 57 ] . glial tnf also causes endocytosis of gabaa receptors resulting in a decrease in inhibitory synaptic currents . homeostatic synaptic scaling of excitatory synapses increases their strength in response to network activity reduction or decreases their strength in response to increased network activity . in response to decreases in network activity , glial tnf was shown to increase ampa - mediated currents by increasing the number of calcium permeable ampa receptors at the cell surface . however , its role may be more permissive rather than instructive in this change . the effects of tnf have also been studied in the dorsal horn of the spinal cord ( see figure 3 ) . intrathecal injection of tnf causes the development of thermal and mechanical hyperalgesia . to investigate the synaptic mechanisms of tnf , incubation with tnf increases the frequency of spontaneous excitatory postsynaptic currents ( sepscs ) in lamina ii excitatory interneurons . tnf increases sepsc frequency via activation of transient receptor potential cation channel subfamily v member 1 ( trpv1 ) in presynaptic terminals , possibly through activation of adenylyl cyclase , protein kinase ( pka ) , or extracellular signal - related kinase ( erk ) . activation of trpv1 results in increased presynaptic calcium influx and , therefore , increased vesicular glutamate release . tnf also acts on the postsynaptic neurons in the spinal cord . in a carrageenan model of inflammation , tnf recruited ca permeable ampa receptors to dorsal horn neurons resulting in increased sepsc amplitude . nmda currents in lamina ii neurons are also enhanced by application of tnf , and tnf increases nmda receptor ( nmdar ) activity through phosphorylation of erk in dorsal horn , neurons . thus via pre- and post synaptic mechanisms tnf increases excitatory neurotransmission in the dorsal horn . in spinal cord slices , tnf not only enhances sepscs but also suppresses the frequency of spontaneous inhibitory postsynaptic currents ( sipscs ) . this was found to be mediated by a decrease in spontaneous action potentials in gabaergic neurons via activation of tnf receptor 1 ( tnfr1 ) and activation of p38 mapk . neurons in the dorsal horn possess both tnfr1 and 2 ( tnfr2 ) , however , tnfr1 seems to make a greater contribution to enhancing nociceptive signaling in the dorsal horn . in spinal cord slices from tnfr1 ko mice , however in tnfr2 ko mice , tnf was still able to produce a small increase in sepcs , and it elicited a normal increase in nmda currents . both tnfr1 and tnfr2 knockout ( ko ) animals show decreased pain behavior in response to complete freund 's adjuvant and formalin induced inflammatory pain as well as intrathecal injection of tnf . thus , microglial release of tnf in the dorsal horn both enhances excitatory neuronal / synaptic activity and suppresses inhibitory neuronal / synaptic activity to enhance central sensitization primarily through the activation of tnfr1 on nociceptive dorsal horn neurons . long - term potentiation ( ltp ) in the spinal cord is implicated in pathological pain . ltp in the spinal cord can be triggered by stimulation of the primary afferent fibers with the typical high - frequency titanic stimulation and also by low - frequency stimulation ( a more physiological firing pattern of nociceptors ) as well as by formalin or capsaicin administration to the paw or by nerve injury [ 16 , 17 , 67 ] . tnf is also important for the induction of spinal ltp , and both tnfr1 and tnfr2 are required for titanic stimulation - induced ltp [ 60 , 69 ] . while the prevailing view is that tnf release from glia activates tnf receptors on neurons to promote ltp , new evidence has recently been found that tnf receptor expression on glial cells is also necessary for the generation of spinal ltp . in the presence of fluorocitrate , a pharmacological blocker of glial activation , tnf failed to potentiate ampar - mediated synaptic currents . this suggests that there is an intermediate step which may facilitate tnf-induced sensitization of dorsal horn neurons . tnf could act on glial cells to elicit the release of additional glial mediators to facilitate its pronociceptive effects . furthermore , pretreatment of slices with the microglial selective inhibitor minocycline inhibits ltp produced by high - frequency stimulation , however , application of tnf reversed the effect , again suggesting that microglial tnf release is important for long - term synaptic plasticity . it is important to note that the effects of tnf vary among regions of the cns particularly at high pathological concentrations . while constitutive tnf release may be permissive for plastic changes in neurotransmission , the activation of microglia can result in 10-fold higher tnf concentrations and , at these high concentrations ( greater than 0.3 nm ) , tnf may change its mode of action . when cultured in the presence of microglia , astrocytic glutamate released is dramatically amplified . in hippocampal slices , high concentrations of tnf may cause prostaglandin e2 mediated glutamate release from astrocytes to the degree that it causes excitotoxic damage in neurons . it has been repeatedly demonstrated that at high concentrations ( 10100 ng / ml ) , tnf inhibited hippocampal ltp [ 7476 ] . however , in spinal dorsal , horn both low and high concentrations of tnf increased c - fiber induced ltp in nerve - injured rats . il-1 is induced in astrocytes , neurons , and microglia in inflammatory and neuropathic pain [ 7780 ] . intrathecal administration of il-1 induces both thermal and mechanical hyperalgesia [ 81 , 82 ] . inhibition of il-1 signaling through administration of il-1 receptor antagonists decreased allodynia in neuropathic pain models [ 77 , 8385 ] . il-1 enhances nociceptive activity in the dorsal horn through some of the same mechanisms as tnf. application of il-1 to spinal cord slices increases sepsc frequency , which indicates enhanced excitatory neurotransmission through increased release of neurotransmitter . importantly , il-1 , but not tnf , increased the amplitude of sepscs , suggesting additional postsynaptic regulation . also similar to tnf , il-1 enhances nmda receptor currents in dorsal horn neurons , albeit by a different mechanism . il-1 induces phosphorylation of the nr1 subunit of the nmda receptor [ 87 , 88 ] . nr1 is an essential subunit of the nmda receptor , and phosphorylation of nr1 increases nmda - mediated inward currents . in both inflammatory and neuropathic pain models , phosphorylation of nr1 increases nmda receptor activity , facilitating excitatory neurotransmission in the dorsal horn [ 8991 ] . application of il-1 to spinal cord slices inhibits both the frequency and the amplitude of spontaneous postsynaptic currents ( sipscs ) . furthermore , application of il-1 is capable of reducing both gaba and glycine mediated currents in dorsal horn neurons . overall , il-1 enhances pronociceptive neurotransmission both through enhancing excitatory neurotransmission and suppressing inhibitory neurotransmission . brain derived neurotrophic factor ( bdnf ) is a secreted protein and part of the family of neurotrophins which act on neurons to promote survival , growth , and differentiation of new neurons and synapses . in the brain , bdnf is important for synaptic plasticity and long - term memory [ 93 , 94 ] . however , in the spinal cord following nerve injury , it plays a deleterious role . following nerve injury , microglia upregulate their expression of the ionotropic atp receptor p2x4 concurrently with the development of allodynia . p2x4 receptor stimulation results in the activation of the p38 mapk pathway and increases the synthesis and release of bdnf from microglial cells . application of bdnf to the spinal cord is capable of producing mechanical allodynia in otherwise nave animals . furthermore , intrathecal administration of microglia activated by atp into nave animals produces mechanical allodynia , which can be alleviated by blockade of the bdnf receptor trkb . thus microglial produce bdnf following nerve injury and bdnf is sufficient to produce pain behavior . microglial derived bdnf contributes to pain hypersensitivity through the disinhibition of nociceptive processing in the dorsal horn . bdnf acts on lamina i pain transmission neurons ; neurons that carry the output message of the dorsal horn to higher brain centers where pain is perceived . bdnf , through the activation of its receptor trkb , decreases expression of the potassium - chloride cotransporter 2 ( kcc2 ) resulting in a rise in intracellular chloride [ 53 , 98 ] . this shift in the neuronal anion gradient is sufficient to suppress inhibition in the majority of lamina i projection neurons , and in some neurons the shift is large enough that their response to application with gaba becomes excitatory rather than inhibitory [ 53 , 99 , 100 ] . the outcome is suppression of the intrinsic inhibitory circuit in the dorsal horn . protein levels of kcc2 are down - regulated in the spinal cord following both spinal cord injury and nerve - injury models in parallel with the development of thermal and mechanical hypersensitivity [ 101 , 102 ] . in nave animals , the suppression of inhibitory drive and thus exaggerated responses of lamina i neurons to normally noxious stimuli explains the development of hyperalgesia , an exaggerated response to normally noxious stimuli , but it does not explain the development of allodynia , the painful response to normally innocuous stimuli . persistent pain sufferers report three cardinal features of their pain : hyperalgesia , allodynia , and spontaneous pain . in vivo recordings from lamina i projection neurons show that following nerve - injury , these neurons begin to respond to nonnoxious stimuli , increase their response to noxious stimuli , and discharge spontaneously . though the mechanism is not fully elucidated , these results can be recapitulated by disrupting the chloride homeostasis of lamina i projection neurons as well as by the addition of atp stimulated microglia , which presumably secrete bdnf . thus microglial derived bdnf may participate further in the development of persistent pain conditions , yet the entire mechanism remains to be elucidated . hyperactivity of peripheral nociceptive fibers due to inflammation or injury causes the release of factors such as ccl2 , atp , and fractalkine into the dorsal horn of the spinal cord [ 48 , 49 ] . , p2x7 , and cx3cr1 on microglia causes activation of proinflammatory cascades and often gliosis [ 4047 ] . p38 mapk acts as a signal integrator of microglia stimulation . activation of p38 results in the production and release of cytokines , chemokines , and proinflammatory mediators that amplify pronociceptive signals in the dorsal horn . we examined the mechanisms of three key signaling molecules released by microglial cells in the context of pain : tnf , il-1 , and bdnf . tnf and il-1 increase presynaptic release of excitatory neurotransmitter as well as increasing excitatory postsynaptic currents through the recruitment of ampa receptors and enhancing nmda currents [ 51 , 6062 , 86 ] . tnf decreases spontaneous activity in gabaergic neurons while il-1 suppresses gaba and glycine mediated inhibitory currents [ 51 , 63 ] . this shifts the chloride gradient of the cell sufficiently to make the normally inhibitory currents resulting from gaba application negligible or even excitatory . therefore , these proinflammatory mediators promote central sensitization through multiple mechanisms to increase excitatory drive and decrease inhibitory drive in dorsal horn nociceptive circuitry . tnf , il-1 , and bdnf also affect long - term neuronal plasticity in the dorsal horn . activation of their respective receptors , tnfr1 , il-1 , and trkb , on neurons leads to the phosphorylation of erk which can enter the nucleus and produce phosphorylation of camp response element binding protein ( creb ) [ 51 , 104106 ] . its activation leads to the transcription of genes such as cox-2 , nk-1 , and trkb which increase neuronal excitability and further promote sensitization [ 106 , 108 , 109 ] . these proinflammatory mediators encourage both short - term and long - term sensory plasticity in the dorsal horn resulting in an increase in ascending nociceptive neurotransmission to the brain . this central sensitization is a key component in the development of hyperalgesia and allodynia associated with persistent pain disorders , and microglia are emerging as a key contributor to central sensitization . recently , studies have found that microglia , like peripheral macrophages , are capable of distinct functional states referred to as classical or alternative activation . classical activation is initiated by ifn , il-1 , and lps which increase production and release of proinflammatory molecules such as tnf and il-1 [ 110 , 111 ] . alternative activation is induced by il-4 , il-13 , il-10 , and tgf which activate anti - inflammatory cascades or tissue repair mechanisms in microglia [ 110 , 112 ] . the anti - inflammatory actions of il-4 and il-13 are mainly a result of their ability to antagonize changes induced by proinflammatory cytokines and suppress the production of il-1 and tnf from microglia [ 113117 ] . additionally , il-4 treatment increases the mrna expression of repair genes , which are also markers of alternative activation in macrophages , such as arginase 1and mannose receptor 1 , found in inflammatory zone 1 and ym1 [ 118 , 119 ] . administration of il-10 and tgf or uptake of apoptotic cells induces an alternative activation state sometimes called acquired deactivation , that as well as being anti - inflammatory is also an immunosuppressive state . however , the majority of studies on alternative activation have been performed using peripheral macrophages , and anti - inflammatory signaling cascades in microglia have not been widely investigated and remain poorly understood . furthermore , it also remains to be seen if these anti - inflammatory cytokines are capable of regulating synaptic plasticity in the dorsal horn . a second class of anti - inflammatory , proresolution mediators are the lipid derivatives resolvins and neuroprotectins . administration of resolvin e1 ( rve1 ) or neuroprotectin / protectin d1 ( npd1/pd1 ) can block tnf induced synaptic plasticity as well as long - term potentiation in the dorsal horn [ 120122 ] . additionally , rve1 is capable of blocking tnf induced increases of postsynaptic nmda currents via regulation of erk [ 121 , 122 ] . rve1 and npd1 can further block lps - induced tnf release in microglia [ 123 , 124 ] . while blocking proinflammatory cytokine production remains a major avenue of clinical pain management , anti - inflammatory and proresolving lipid mediators may provide new avenues for controlling clinical pain .

microglia are regarded as macrophages in the central nervous system ( cns ) and play an important role in neuroinflammation in the cns . microglial activation has been strongly implicated in neurodegeneration in the brain . increasing evidence also suggests an important role of spinal cord microglia in the genesis of persistent pain , by releasing the proinflammatory cytokines tumor necrosis factor - alpha ( tnf ) , interleukine-1beta ( il-1 ) , and brain derived neurotrophic factor ( bdnf ) . in this review , we discuss the recent findings illustrating the importance of microglial mediators in regulating synaptic plasticity of the excitatory and inhibitory pain circuits in the spinal cord , leading to enhanced pain states . insights into microglial - neuronal interactions in the spinal cord dorsal horn will not only further our understanding of neural plasticity but may also lead to novel therapeutics for chronic pain management .

the search for quark hadron phase transition and the investigation of the properties of quark gluon plasma stand among the most challenging as well as rewarding pursuits of high energy nuclear physics today . the observations of jet - quenching @xcite and the elliptic flow @xcite , and the success of the partonic recombination @xcite as a model for hadronization in recent experiments at the relativistic heavy ion collider at brookhaven presage the shift of the focus to even more interesting questions about how the plasma is formed and how does it evolve . it is expected that the quantum statistical interference between identical particles emitted from the relativistic heavy ion collisions will provide valuable inputs for these investigations . the pion intensity interferometry experiments have however thrown up some startling questions , which need to be answered before we can address these issues . the hydrodynamics models which have traditionally provided a quantitative description to data on particle spectra and elliptic flow , fail to explain the near identity of the so - called outward and side - ward radii seen in these experiments and invariably lead to outward radii which are up to a factor of 2 larger than the side - ward radii @xcite . an investigation of the structure and dimensions of the source in terms of photon interferometry should provide a more direct and valuable insight into these questions . the advantages of using photons for such studies is well known @xcite ; they interact only weakly with the system after their production and are free from such distorting effects as the re - scattering @xcite and coulomb interactions , which have dogged these investigations using identical hadrons . photons are also emitted at every stage of the collision dynamics and from every point in the system- and not only from the freeze - out surface . we note though that some studies have postulated that pions may be emitted not only from the surface as normally assumed ; they also escape the system continuously from all points in the system @xcite with some escape probability . a large probability for this will however be hard to justify , as the pions do interact strongly with the hadroinc medium . still this possibility along with the modifications introduced due to final state interactions for hadrons , necessitates a great deal of further study before the radii obtained from the intensity interferometry of hadrons are used to get the spatial and temporal extent of the source in these collisions . theoretical investigations of the nature of the photon correlation function for relativistic heavy collisions , where a quark - gluon plasma may be formed have been carried out by several authors @xcite . an experimental measurement is a far more difficult proposition though , due to the huge back - ground of decay photons and a considerably smaller production of direct photons . thus , so far only one experiment at cyclotron energies @xcite ( where direct photons mostly originate from bremsstrahlung of protons against neutrons ) , and a measurement by the wa98 collaboration @xcite ( where photons originate from hadronic reactions and possibly quark matter ) for the central collision of lead nuclei at cern sps have been reported . it is expected that such experiments will have a higher possibility of success at rhic and lhc energies . firstly , the larger initial temperatures expected there will lead to a larger production of direct photons . secondly , a large suppression of high momentum pions due to the onset of jet - quenching will lead to a reduction in the back - ground from the decay photons . furthermore , a large production of photons having high @xmath1 is expected from the pre - equilibrium stage of the collision @xcite , which can be reliably crafted using the parton cascade model @xcite and it has been shown to have a very distinct distribution of the source @xcite . the early theoretical investigations @xcite of photon interferometry were also aimed at isolating photons coming from the quark matter from those coming from the hadronic matter . these studies concentrated on photons having high transverse momenta ( @xmath2 1 gev ) , which are more likely to be emitted from the early hot and dense phase of the plasma . in the present work we focus our attention on the photons having low and intermediate @xmath0 100 mev the photons at the lower end of the @xmath1 range considered would have a dominant contribution from the late stages of the hadronic phase . this should reveal a source which is strongly affected by the radial flow . the higher end of the @xmath1 should have a leading contribution from the early hot and dense stage of the plasma , when the flow is still small and the temperature is large . we also incorporate several improvements over the early exploratory works @xcite . firstly , we use the complete leading order results for the production of photons from the quark matter @xcite , which has important contributions from the bremsstrahlung , and annihilation of off - shell quarks @xcite . secondly , for hadronic reactions we use the state of the art results from turbide et al . @xcite along with inclusion of hadronic form - factors at the vortexes , incorporating strange mesons . the dominant hadronic bremsstrahlung process ( @xmath3 ) is included @xcite for low @xmath1 photons and double counting via @xmath4 and @xmath5 avoided by limiting the contributions of the latter two processes to @xmath6 500 mev . this should be adequate till a more detailed and complete calculation is available . finally , we use a much richer equation of state for the hadronic matter , with the inclusion of all the particles in the particle data book , having @xmath7 2.5 gev . results of our model calculations are compared with the recent data obtained by the wa98 experiment and predictions given for rhic and lhc energies . we shall see that the competition between the cooling due to expansion and the blue - shift of the photon spectra due to transverse expansion give rise to a unique @xmath1 dependence of the outward and side - ward correlation radii , which evolves rapidly as the initial temperature of the system changes , as we go from sps to rhic to lhc . we first discuss the tools necessary for the analysis of the intensity interferometry and briefly discuss the initial state and the rate of production of photons . next we check whether the description used by us provides a reasonable description of the single photon spectra measured at . the results for some typical momenta of the photons and transverse momentum dependence of correlation radii are discussed next . finally we give our conclusions . the spin averaged intensity correlation between two photons with momenta @xmath8 and @xmath9 , emitted from a completely chaotic source , is given by : @xmath10 where @xmath11 is the space - time emission function , and @xmath12 in a hydrodynamics calculation , the space - time emission function @xmath13 is replaced by the rate of production of photon @xmath14 , in the hadronic or the quark matter , as discussed earlier . the results for the correlation function @xmath15 are best discussed in terms of the so - called outward , side - ward , and longitudinal momentum differences . thus for the four - momentum @xmath16 of the @xmath17th photon , we have , @xmath18 with @xmath19 where @xmath1 is the transverse momentum , @xmath20 is the rapidity , and @xmath21 is the azimuthal angle . defining the difference and the average of the transverse momenta , @xmath22 we can write @xcite , @xmath23 the corresponding radii are obtained by approximating : @xmath24 \label{actual}\end{aligned}\ ] ] note that for this choice of parametrization for the correlation function @xmath25 , where @xmath26 , @xmath27 and @xmath28 , and the average is performed over the distribution @xmath29 . a one dimensional analysis of the correlation function @xmath30 is some - times performed in terms of the invariant momentum difference @xmath31 . \label{one_1}\ ] ] where @xmath32}.\end{aligned}\ ] ] however the significance of the corresponding radius does not have a clear meaning @xcite , and it is also not useful for comparing results obtained using different particles . the variable @xmath33 is also occasionally used for a one dimensional analysis @xcite , and one writes : @xmath34 . \label{one_2}\ ] ] note also that @xmath35 . here , it is useful to realize that in actual studies of photon interferometry the correlation function @xmath30 would be parametrized as : @xmath36\end{aligned}\ ] ] where @xmath37 is a measure of single ( s ) vs. decay photons ( d ) , under the assumption that the source is completely chaotic . obviously the later do not contribute to the correlation ( the life - time of @xmath38 is @xmath39 seconds ) and thus : @xmath40 so that @xmath41 and therefore using the measured values of the total photon yield ( @xmath42 ) at the momentum @xmath43 , we can get the yield of single photons from the intercept of @xmath30 on the @xmath20-axis ( peressounko @xcite ) . this can provide a check on the results on single photon obtained by , say , a subtraction of photons from decay of pions and etas . it is important to realize that this procedure is not directly applicable to the case where only a one - dimensional analysis in terms of @xmath44 ( eq.[one_1 ] ) is performed . the photon - pairs having transverse momenta in some bin around @xmath45 , rapidity difference within @xmath46 , and azimuthal angle difference within @xmath47 will lead to a range of outward , side - ward , and longitudinal momentum differences which will decide the actual correlation function @xmath30 ( eq.[actual ] ) . even a given value of @xmath44 will admit a range of these momentum - differences , and thus the value of one - dimensional @xmath30 will be obtained by taking an average over the corresponding results . this will lead to an effective @xmath37 which will not reduce to unity , even if there were no decay - photons @xcite . this `` effective '' @xmath37 , as well as the @xmath48 will depend upon @xmath45 , @xmath49 , @xmath46 , @xmath47 , and the correlation radii , @xmath50 , @xmath51 , and @xmath52 . thus the direct photon yield can be measured only by assigning a value to these radii and becomes model dependent . of - course , @xmath48 can be assigned , though its meaning remains unclear and it remains model dependent . a simple instance should exemplify this issue . consider a case where @xmath53 and @xmath54 so that @xmath550 ( see eq.([q_l]-[q_s ] ) ) . in this case @xmath56 , but @xmath57 0 . thus the `` true '' correlation function ( eq.[actual ] ) will be decided by the value of the outward momentum difference and the outward correlation radius , while naively one would expect the one dimensional correlation function ( eq.[one_1 ] ) , to reduce to 1.5 . thus even for a case when there are no decay photons , we would need a correction factor to account for the range of values admitted by the `` true '' correlation function . the procedure may however still work for the one - dimensional analysis in terms of the variable @xmath58 ( eq.[one_2 ] ) , as this vanishes only when all the three momentum - differences , @xmath59 , @xmath60 and @xmath61 also vanish simultaneously . the meaning of the corresponding radius and its relation to the outward , side - ward and longitudinal correlation radii , remains unclear though . while we are discussing the merits of the one dimensional analysis in terms of the invariant momentum difference , @xmath44 , we recall that for typical cases , the correlation function @xmath30 differs substantially from unity for momentum differences @xmath62 0.2 gev . for studies using single photons this limit has to be less than @xmath63 , to stay clear of the @xmath38 peak . if @xmath64 are large , choosing @xmath46 and @xmath47 as small , we can get very small values of the side - ward , outward , and longitudinal momentum differences . however as @xmath65 , small values for @xmath44 can be obtained only if @xmath64 are quite small . for larger value of @xmath64 , the necessary @xmath46 and @xmath47 bins would be too small to admit meaningful statistics . thus , it is no wonder that both the photon interferometry experiments reported in the literature so far @xcite , use the one - dimensional analysis in terms of @xmath44 and utilize photons having very low @xmath1 . we hope that a much larger statistics expected at rhic and lhc will help us get over this problem by providing results for the full 3-dimensional correlation function . we very briefly recall the treatment for the space - time evolution of the system and the production mechanism of the photons in these calculations . for the first set of calculations , we consider central collision of lead nuclei , corresponding to the conditions realized at the cern sps . we further assume that a thermally and chemically equilibrated quark - gluon plasma is produced in such collisions at the initial time @xmath66 , and use the assumption of is - entropic expansion to estimate the initial temperature , @xmath67 . thus we have @xmath68 where @xmath69 is the transverse area of the system , @xmath70 is the particle rapidity density , and @xmath71 for a plasma of massless quarks ( u , d , and s ) and gluons . the number of flavours for this purpose is taken as @xmath72 2.5 to account for the mass of the strange quarks . we further assume a rapid thermalization of the plasma , constrained by the uncertainty relation , @xmath73 . the initial energy density is taken as proportional to the `` wounded - nucleon '' distribution , appropriate for sps energies . the quark - hadron phase transition is assumed to take place at 180 mev , and the freeze - out at 100 mev . the relevant hydrodynamic equations are solved under the assumption of boost - invariant longitudinal and azimuthally symmetric transverse expansion using the procedure discussed earlier @xcite and integration performed over the history of evolution . this procedure is known to give an accurate description of hadronic spectra @xcite . we have already indicated the sources for evaluation of rates of photon production from quark and hadronic matter . as a first step we plot the rate of production of single photons due to all the reactions among mesons considered in ref.@xcite . ( see fig . [ fig1 ] ) at @xmath74 180 mev . we see that the inclusion of the form factor considerably reduces the rate for production of photons having higher energies , leaving the results for the lowest energy photons unaltered . we also give the results for the rates from quark matter at the same temperature . it should be remembered that photon intensity interferometry should be less sensitive to the specific details of the rates of production from quark and hadronic matter , but should depend on their relative strengths . in order to uniquely establish the importance of the mandatory requirement of including the form - factors discussed in ref . @xcite , we plot ( see fig . [ fig2 ] ) the sum of the production of thermal photons from the quark matter and the hadronic matter in a collision of lead nuclei at the cern sps , with the initial conditions discussed earlier . the data obtained by the wa98 experiments @xcite and the production from the quark - matter are also shown for a comparison . we immediately note that the exclusion of the form - factors will considerably overestimate the production of single photons at higher @xmath1 , as it is well established from several studies that up to half of the single photons measured by the wa98 experiment have their origin in the prompt - qcd process , which should be added to the thermal photons to get a quantitative description of the production of the single photons . we further note that the calculations underestimate the data by a factor of 7 9 at the lowest @xmath1 reported recently @xcite ( see discussion later ) . finally , in fig . [ fig3 ] we show our results for the production of single photons , by summing the thermal contributions ( with the inclusion of form - factors while estimating the hadronic rates ) and the prompt - qcd contribution . for the later we use a parametrization of all the @xmath75 data @xcite and scale it for collision of lead nuclei . we account for the intrinsic @xmath1 of the partons by multiplying this scaled @xmath75 contribution by a factor of 2 . we see that the sum of the thermal and prompt contributions provides a satisfactory explanation of the single photon spectrum at large @xmath1 in the present model . we also note that while an inclusion of the pionic bremsstrahlung improves the description of the data at the lower @xmath1 marginally , the theoretical calculations are still well below the estimated ( see later ) experimental results . we can think of two possible reasons for this shortfall . one possibility is that there may be additional reactions , e.g. , involving baryons , which may contribute at low @xmath1 . the other , and possibly more plausible , reason could be the neglect of the pionic chemical potential @xcite in the present work , and which can arise arise to - wards the end of hadronic phase @xcite . let us elaborate on this aspect . recall that the pion - chemical potential ( @xmath76 ) may reach a value of about 60 mev in collision of lead nuclei at sps energies@xcite when @xmath77 drops to 100 mev . this will imply an enhancement in the rate of production of photons from the hadronic matter by approximately a factor of @xmath78 for every pion in the entrance channel , and also some increase due to bose enhancement factor in the exit channel , if there is a pion there . these aspects are under investigation . we may add however that the inclusion of these corrections should not drastically alter the following results , as the hadronic phase contributions , already dominate the yield of photons at low @xmath1 , considerably . the calculations at rhic and lhc energies are performed in an analogous manner , taking @xmath70 at @xmath79 as 1260 and 5625 @xcite respectively for central collisions of gold ( at rhic ) and lead ( at lhc ) nuclei . this procedure has been discussed repeatedly in literature ; the only difference we have in the present work is that we use the state of the art results for the rates , and a more complete equation of state for the hadronic matter . as a first step , let us investigate the differences in the patterns of the intensity interferometry of photons having high and low @xmath1 . thus we perform calculations by choosing @xmath64 , @xmath80 , and @xmath81 of photons such that two of the three momentum differences , @xmath59 , @xmath60 , and @xmath61 , vanish in turn . this theoretical construction helps us obtain the corresponding correlation functions . we show typical results for @xmath82 0.15 gev , 1.05 gev , and 1.95 gev in fig . we see a very interesting feature in the outward correlation function : as the transverse momentum of the photon increases , we see a clear emergence of two sources , one which has a smaller correlation radius ( see larger @xmath59 ) and the other which has a larger correlation radius . this aspect has remained a recurring theme in results for photon intensity interferometry @xcite and has its origin in the emissions from quark and the hadronic phases respectively which have vastly differing source dimensions . it is interesting that this feature noted in early exploratory studies has survived the vast improvements in the rate calculations and the dynamics of evolution . the emergence of the two source structure at larger @xmath1 is facilitated by the decreasing contribution of the hadronic phase there . this feature is not expected for pion intensity correlations as they leave the system mostly at the time of freeze - out only . the side - ward correlations show a decreasing radial dimension as @xmath1 increases , as expected for a transversely expanding source , and look gaussian in nature . the longitudinal correlation function also shows a similar behaviour , as far as the variation of the correlation radius is concerned , however it is definitely not gaussian in form . thus neither the function ( eq.[actual ] ) describes these variations satisfactorily , nor does the procedure of taking @xmath83 , where @xmath84 denotes the momentum difference where @xmath85 has dropped by a factor of @xmath86 compared to its value at @xmath87 , can do a full justice to these distributions . in view of the above , we have numerically evaluated : @xmath88 where @xmath89 and plotted it as a function of @xmath90 in fig . [ fig5 ] . the @xmath1 variation of the @xmath50 reveals a very rich structure . in order to fully appreciate the observations , we recall that the source of photons has a dependence @xmath91 where @xmath92 2 , and @xmath93 is the energy of the photons in the rest frame of the fluid . this is very distinct from the corresponding dependence for pions , which varies as @xmath94 , where @xmath95 is the freeze - out temperature and contributions accrue from locations along the freeze - out surface . the `` reclining chair '' behaviour seen in this variation is an outcome of competition between a high temperature ( limited to small radii and early times ) and a large transverse flow velocity ( predominant at large radii and late times ) in producing photons having moderate @xmath1 . thus the large radial flow ensures that photons having a large @xmath1 can also be produced at later times , thus enhancing the so - called duration of the source measured as @xmath96 . we shall see later that the the ` seat ' of this `` reclining chair '' gets narrower for rhic energies and vanishes at lhc energies , as the increasing radial flow rapidly cools the system . a hint of this behaviour is also present in the momentum dependence of the side - ward correlation radius , which decreases almost linearly with @xmath1 . the momentum dependence of the longitudinal correlation radius is completely different from the @xmath97 expected for pions @xcite . we see that @xmath52 for photons is almost inversely proportional to the transverse momentum . we believe that these differences do arise due to the difference in the source function for photons and pions . let us now look at our results for the one - dimensional analysis of the correlation function in terms of the invariant momentum difference @xmath44 corresponding to the transverse momentum , and rapidity window used in the wa98 experiment @xcite . our results with all the kinematic cuts are shown in fig . [ fig6 ] . in order to simulate the probabilistic selection of photons , we first generated a sufficiently large number of photons according to the thermal distribution calculated by us earlier , in the transverse momentum window of @xmath98 $ ] gev , and ( randomly ) distributed them uniformly over the azimuthal directions and the rapidity window corresponding to the experiment . next we sampled pairs so that their average transverse momentum @xmath45 was in the appropriate window . the correlation function was then calculated using the expression eq.([def ] ) . the results were then averaged by binning in @xmath44 . we see that our results are described to a reasonable accuracy by the form : @xmath99 \label{fit}\ ] ] where @xmath100 6.5 fm for @xmath101 gev and 5.3 fm for the transverse momentum window @xmath102 gev . in order to compare our results with the numbers quoted the wa98 experiment @xcite we need to multiply their results with @xmath103 as the fits discussed in that work do not include the factor of 2 in the exponential used in the present work ( eq.[one_1 ] ) . thus the corresponding experimental results for the @xmath48 obtained by the wa98 experiment are 8.34 @xmath104 1.7 fm and 8.63 @xmath104 2.0 fm , respectively . while our predictions are in reasonable agreement with the `` experimental '' findings ( within the errors ) , the experimental results are on the larger side . before passing a judgment on our results , recall that that the values quoted by the wa98 experiment are obtained by assigning a values of 7.85 and 7.25 fm for the @xmath51 , 8.4 and 7.7 fm for the @xmath52 and 8.5 fm for the @xmath50 based on the values obtained for pion interferometry @xcite . our results for the @xmath51 are 4.93 and 4.85 fm , for the @xmath52 are 3.7 and 2.5 fm , and for the @xmath50 are 9.97 and 9.39 fm respectively at @xmath1 = 0.15 and 0.25 gev respectively ( see fig.[fig5 ] ) . thus we feel that the results for the @xmath48 as well as the results for the single photons at low @xmath1 quoted by the wa98 experiment ( based on the value of the parameter @xmath105 in the eq.([fit ] above ) , are model dependent and uncertain to the extent that they use correlation radii determined from pion interferometry . we also see that at least the side - ward and the longitudinal radii for photon correlations are much smaller than the corresponding values for the pion interferometry . a full three dimensional determination of the correlation function will go a long way in getting reliable results and constraining the theoretical calculations discussed here . we now present results for correlation functions for thermal photons at rhic and lhc energies ( see figs.[fig7][fig10 ] ) . looking at fig . [ fig7 ] , for central collisions of gold nuclei at rhic energies , we note that the two - source aspect in the out - ward correlation function becomes more clear , due to increased contributions from the ( smaller but stronger ) quark - matter . of - course , it is known @xcite that we shall have a large contribution of pre - equilibrium photons at larger @xmath1 and this trend should continue at lhc energies . this will further enhance the contribution of the smaller - sized source , and the structure seen here , will disappear . the transverse momentum dependence of the source sizes ( fig . [ fig8 ] ) , is similar in nature to what we see at sps energies , though the ` seat ' of the ` reclining chair ' seen in the out - ward size gets narrower , as one would expect for a more rapidly expanding source . the longitudinal correlation length is again seen to decrease rapidly with the increase in the transverse momentum . these trends continue at lhc energies ( fig . [ fig9 ] ) and the transverse momentum dependence of the source sizes ( fig . [ fig10 ] ) becomes very pronounced . the so - called ` seat ' in the outward correlation vanishes completely , and all the radii decrease roughly as @xmath106 , with @xmath107 @xmath72 0.27 for the outward correlation , about 0.14 for the side - ward correlation and about 0.94 for the longitudinal correlation . we note that at none of the energies , the longitudinal correlation function resembles a gaussian , as normally assumed in parametrization . this is perhaps related to the emission of the photons from all the points in a longitudinally expanding system . in fact , similar shape is seen for the longitudinal correlation function for pions ` escaping ' from the system @xcite and for pions produced from partonic cascades @xcite . the difference of the out - ward and side - ward correlation radii is often associated with the life - time of the source . in order to see the evolution of this parameter with the transverse momentum of the thermal photons we plot their difference as well as their ratios in fig . [ fig11 ] , for the three systems studied in the present work . we see the ` reclining chair ' behaviour for the sps energies , and a more rapid decrease as we go from rhic to lhc energies . several interesting results emerge . firstly the difference @xmath108 is nearly unaltered as we go from sps to rhic for photons having transverse momenta less than 0.5 gev . we have already noted that the ` seat ' of variation is caused by the competition between cooling due to expansion and the blue - shift of the momenta due to the transverse flow . the more rapid decrease of the difference arises due to a more rapid cooling and an increased flow as the initial temperature rises . the same trend is seen for the ratios . an experimental confirmation or a refutation of theses predictions will be very valuable . before summarizing , it may be of use to discuss some aspects which we have overlooked in the present work . it should be of interest to examine the role of the reactions of the type @xmath109 or @xmath110 , for the intensity interferometry of photons . firstly , the quark matter contribution to single photons is already marginal for low transverse momenta , which is the subject of our focus here . then we note such photon pairs ( `` diphotons '' ) will be produced at ` a point ' and not at different locations like a pair which comes from , say , @xmath111 and @xmath112 . more - over their transverse momentum difference @xmath113 , where @xmath1 is the transverse momentum of either photon . for calculations which we can treat perturbatively , this difference is at least an order of magnitude larger than the values of @xmath114 where the correlation function has a significant value . of - course one could include them as a source of single photons . however they are suppressed by a factor @xmath115 compared to the @xmath116 , say . let us also discuss the role of direct ( qcd ) photons to the @xmath1 region under consideration here and for which we have experimental data at sps energies from the wa98 experiment . in addition to the results given here , calculations have been reported by dumitru et al . @xcite , where large values for intrinsic momenta of partons are used to exhaust the wa98 data beyond @xmath117 3 gev . the calculations exhaust only about 50% of the single photon yield at 2 gev ( as in the present work ) and less than 20% of the yield at 1 gev . turbide et al . @xcite have extrapolated the pqcd results down to zero transverse momenta ( ! ) and find that the thermal photon yield is up to 4 orders of magnitude larger than the direct photon yield at lower transverse momenta . parton cascade model calculations for sps energies @xcite show the dominance of quark matter contributions beyond 3 gev ( including photons which could be termed thermal , from the quark - matter ) but a much smaller production from them at lower @xmath1 . these considerations should convince us that indeed thermal photons dominate in the region of transverse momenta considered here . we may also recall here the results of two works , which address similar issues . peressounko @xcite has used hydrodynamics calculations with rates for the production of photons from quark matter and hadronic matter , along with the photons from the decay of pions to get @xmath37 as well as the correlation radii , for direct photons . while the @xmath50 and the @xmath52 vs. @xmath1 behaviour estimated by him are similar to ours , his work shows a very unusual result : the @xmath51 actually increases , and that too substantially , with increase in @xmath1 . considering that photons having large transverse momenta are produced very early in the collision when the transverse expansion has not yet set - in , this is hard to understand . similarly , the decrease in the values of the correlation radii , as @xmath1 decreases below 0.5 gev at sps energies is also difficult to fathom . other differences could be attributed to the more complete rates for photon production used in the present work . the work of renk @xcite is interesting in that it uses a fire - ball description to model the collision at sps and rhic energies . the parameters of the fireball are adjusted to reproduce the pion spectra as well as the hbt radii for pions . the differences seen in the present work then arise due to the explicit appearance of a mixed phase here , during which the speed of sound is zero and acceleration of the expansion is stalled . results of an investigation using different equations of state , including one which does not admit a mixed phase , will be published shortly . in brief , the side - ward , out - ward , and longitudinal correlation functions for intensity interferometry of thermal photons at sps , rhic , and lhc energies are calculated . the transverse momentum dependence of these radii are very different from the corresponding results for pions , which are expected to decrease as @xmath118 for all the components . the longitudinal correlations for the three energies are quite similar and may be indicative of boost - invariance of the flow assumed in the work . the ratio @xmath119 at lhc decreases rapidly and approaches unity , due to increase in @xmath51 due to expansion and decrease in @xmath50 due to rapid cooling . as the results are free from distortions due to final state interactions and uncertainties about the production - vertexes , or the production mechanism of the particles under investigation , a confirmation or refutation of the findings will be very valuable . phenix collaboration , s. s. adler et al . lett . * 91 * , 182301 ( 2003 ) ; star collaboration , c. adler et al . , rev . lett . * 90 * , 032301 ( 2003 ) ; _ ibid _ * 89 * , 132301 ( 2002 ) ; _ ibid _ * 87 * , 182301 ( 2001 ) . r. j. fries , b. mller , c. nonaka , and s. a. bass , phys . . lett . * 90 * , 202303 ( 2003 ) ; v. greco , c. m. ko and p. levai , phys . lett . * 90 * 202302 ( 2003 ) ; d. molnar and s. a. voloshin , phys . lett . * 91 * 092301 ( 2003 ) ; c. nonaka , r. j. fries , and s. a. bass , phys . b * 583 * , 73 ( 2004 ) . d. k. srivastava and j. i. kapusta , phys . b * 307 * , 1 ( 1993 ) ; d. k. srivastava and j. i. kapusta , phys . c * 48 * , 1335 ( 1993 ) ; d. k. srivastava , phys . d * 49 * , 4523 ( 1994 ) ; d. k. srivastava and c. gale , phys . b * 319 * , 407 ( 1994 ) ; d. k. srivastava and j. i. kapusta , phys . c * 50 * , 505 ( 1994 ) . a. timmermann , m. plmer , l. razumov , and r. m. weiner , phys . c * 50 * , 3060 ( 1994 ) ; j. pisut , n. pisutova and b. tomasik , phys . b * 345 * , 553 ( 1995 ) , [ erratum - ibid . b * 353 * , 606 ( 1995 ) ] ; c. slotta and u. w. heinz , phys . b * 391 * , 469 ( 1997 ) ; d. peressounko , phys . c * 67 * , 014905 ( 2003 ) ; j. alam , b. mohanty , p. roy , s. sarkar , and b. sinha , phys . c * 67 * , 054902 ( 2003 ) ; t. renk , hep - ph/040812 . s. a. bass , b. mller and d. k. srivastava , phys . b * 551 * , 277 ( 2003 ) ; s. a. bass , b. mller and d. k. srivastava , nucl . a * 715 * , 813 ( 2003 ) ; s. a. bass , b. mller and d. k. srivastava , j. phys . g * 30 * , s1283 ( 2004 ) . jan - e . alam , d. k. srivastava , b. sinha , and d. n. basu , phys . d * 48 * , 1117 ( 1993 ) ; j. cleymans , k. redlich , and d. k. srivastava , phys . c * 55 * , 1431 ( 1997 ) ; d. k. srivastava , eur . j. c * 10 * , 487 ( 1999 ) ; erratum - ibid , c * 20 * , 399 ( 2001 ) .

intensity interferometry of thermal photons , having transverse momenta @xmath0 0.1 2.0 gev , produced in relativistic collision of heavy nuclei is studied . it is seen to provide an accurate information about the temporal and spatial structure of the interacting system . the source dimensions and their @xmath1 dependence revealed by the photon interferometry , display a richness not seen in pion interferometry . we attribute this to difference in the source functions , the fact that photons come out from every stage of the collision and from every point in the system , and the fact that the rate of production of photons is different for the quark - gluon plasma , which dominates the early hot stage , and the hadronic matter which populates the last phase of the collision dynamics . the usefulness of this procedure is demonstrated by an application to collision of lead nuclei at the cern sps . prediction for the transverse momentum dependence of the sizes for sps , rhic , and lhc energies are given .

retinitis pigmentosa ( rp ) is an inherited retinal disease characterized by the degeneration of photoreceptor rods and cones [ 1 , 2 ] . in the majority of rp cases , there is a primary degeneration of rod photoreceptors with a secondary degeneration of cones . this explains why patients show only a night blindness at first and a visual impairment later in daylight [ 3 , 4 ] . in some cases , the clinical presentation is cone - rod dystrophy type with a predominant involvement of the cones or the central retinal photoreceptors . the decrease of visual acuity consequently predominates over visual field loss [ 1 , 5 ] . the worldwide prevalence of retinitis pigmentosa is about 1 in 4,000 healthy people for a total of over 1 million people affected . in the usa it is about 1 : 35001 : 4000 with significant differences between the various states ; in switzerland 1 : 7000 ; china 1 : 4016 ; norway 1 : 4440 ; in israel 1 : 4500 . the disease can be inherited as autosomal - dominant ( about 3040% of cases ) , autosomal - recessive ( 5060% ) , or x - linked ( 5 to 15% ) . on the basis of this data , an observational study was performed on a sample of individuals suffering from retinitis pigmentosa . in the literature , we did not find any other studies concerning the alterations of ocular motility in retinitis pigmentosa . the purpose of the study was to highlight the presence or absence of eye movement disorders in a genetically determined disease like rp while excluding all those influential factors used in recruiting binocular vision and the development of abnormal ocular motility such as high refractive errors , visual acuity < 6/10 , pituitary adenomas , and related eye diseases in order to show the type of muscle alteration , if present , and then reconnect it to a genetic cause like rp . our sample consisted of 50 eyes ( 25 individuals ) with retinitis pigmentosa from the center for pediatric ophthalmology at the eye clinic of the policlinico umberto i , university of rome la sapienza . patients were evaluated by the same examiner , and after a careful history and a thorough eye examination of both the anterior segment and posterior segment with indirect ophthalmoscopy ( schepens ) , they were put through the following orthotic tests : visual acuity or visual acuity;corneal reflex ( cr);stereopsis test;cover test ( ct);ocular motility ( om);convergence objective . visual acuity or visual acuity ; ocular motility ( om ) ; convergence objective . the inclusion criteria of our study were as follows.age between 6 and 80.patients with the typical form of nonsyndromic rp and patients with syndromes that are associated with various types of pigmentary retinopathy ( e.g. , usher syndrome , cockayne syndrome , best 's disease , etc.).patients with suspected rp : by careful history the presence of rp was discovered in other family members ( i.e. , brother , cousin , and grandparent).visual acuity between 6/10 and a maximum of 10/10 ( via the snellen optotype ) . patients with the typical form of nonsyndromic rp and patients with syndromes that are associated with various types of pigmentary retinopathy ( e.g. , usher syndrome , cockayne syndrome , best 's disease , etc . ) . patients with suspected rp : by careful history the presence of rp was discovered in other family members ( i.e. , brother , cousin , and grandparent ) . visual acuity between 6/10 and a maximum of 10/10 ( via the snellen optotype ) . the exclusion criteria were as follows.preschool age ( from 1 to 5 years).patients who had undergone ocular surgery.patients with systemic , vascular , and neurodegenerative disease ( e.g. , the multiple sclerosis ) that can affect the orthoptic assessment.patients with visual field ( cv ) electronic humphrey < 10.visual acuity below 6/10.presence of pituitary adenomas . patients who had undergone ocular surgery . patients with systemic , vascular , and neurodegenerative disease ( e.g. , the multiple sclerosis ) that can affect the orthoptic assessment . patients with visual field ( cv ) presence of pituitary adenomas . in the evaluation of ocular motility , we considered the 12 extraocular muscles of both eyes in different positions of gaze . we have assigned a gradient equal to 0 in the case of normal ocular motility , + 1 in the case of mild hyperfunction , + 2 in the presence of moderate , and + 3 in the case of severe hyperfunction . the same score was given in the case of hypofunction of the contralateral synergist muscle but with a negative value . a statistical analysis of this pilot study was performed by a pearson correlation between the contralateral synergist muscles : ri sr - le so , ri ir - le go , le sr - riso , and le ir - ri go . the sample consisted of 25 individuals but was reduced to 23 individuals , because two patients reporting a severe mental retardation ( iq < 40 ) were unable to cooperate with most important orthotic tests such as an accurate assessment of ocular motility . thus , out of the 25 individuals , 23 have been included with 9 females and 14 males . the average age for women was 45 years 25.18 sd while the average age found in men was 43 age 21.42 sd ( figure 1 ) . of the 23 patients included , 69.5% were suffering from typical retinitis pigmentosa ( rod cone dystrophy ) and 4.3% by rp atypical ( cone - rod dystrophy ) . patients with syndromes associated with rp ( such as s. cockayne and s. uscher ) showed the same percentage of disease incidence of 4.3% . among macular dystrophy , best 's disease was found in 13.3% : 4 patients belonging to the same family ( father with sons and grandson ) . we also found a case report with cones dystrophy ( incidence 4.3% ) . among refractive defects found in our sample , we found the presence of myopia with an average of 1 diopter 3.15 sd for the right eye and 1.5 diopter 3.53 sd for the left eye . in fact , there has only been an average of 0.25 for the right eye with sd equal to 1.13 . this data showed refractive errors ( myopia of middle - grade and low , irrelevant , astigmatism ) that are not able to affect binocular vision and therefore the ocular motility of the tested patients ( figure 2 ) . in the evaluation of visual acuity in tenths by the snellen optotype , it is appropriate to mention the presence of an average of 6/10 sd of 2.9 for the right eye and 3.2 for the left eye . this data does not show a significant reduction in visual acuity that can hinder the development of binocular vision . the latter has also been evaluated through some stereoscopic tests ( lang i and ii ) that show full results in 22 of the 23 patients . in only one patient ( a child with exotropia ) and when detecting only the star image , the three - dimensional sense was absent . we can say that the development of binocular vision is not compromised due to alack in the whole sample of diplopia guarantor of an optimal sensorial fusion . thereafter in the study of fusional amplitude , except for the young exotropic girl , the rest of the sample showed normal motor fusion values . in the evaluation of ocular motility , we took into account the different positions of gaze : primary position , left , right , up , up right and left , down , down left , and right . it was found that no patient had an alteration of the medial rectus muscle , and the lateral rectus was present in the right and left side sight . it is necessary , however , to highlight the presence of the alteration in 50% of the sample in various degrees of ocular motility regarding the small oblique muscles , large oblique , rectus superior , and inferior rectus . in the upper left gaze , there has been a severe grade ( score = + 3 ) hyperfunction of the small oblique muscle ( so ) of the right eye in 39.1% of cases compared with a normal ocular motility ( score = 0 ) in 34.7% of our sample . we also verified a moderate hyperfunction ( score = + 2 ) in 17.4% of cases and an equal incidence of 4.4% of the cases in both the mild hyperfunction ( score = + 1 ) and the severe hypofunction ( score = 3 ) of the muscle . besides finding a severe hyperfunction of the right so in the look upward and left , we found in 30.5% of the cases studied the presence of a severe hypofunction of the contralateral synergist , namely , the superior rectus of the left eye . in addition , out of the 23 individuals , we also found a normal motility in 34.8% of cases , a moderate hypofunction in 21.8% of cases , a severe hyperfunction in 8.6% , and a mild hypofunction in 4.3% for the superior rectus muscle of the left eye . in the ocular motility evaluation , we also took into consideration the position of gaze at the bottom left . in that position , we found the presence of a hypofunction of the great oblique muscle of the right eye of a moderate degree ( score = 2 ) . in 21.8% of the 23 individuals considered and , on the other hand , in 61% of cases , with the same percentage of the total 4.3% , the large oblique muscle of the right eye showed a moderate hyperfunction , a mild hyperfunction , and a severe hypofunction . in versions , considering the gaze of eyes to the bottom left , the grand oblique muscle of the right eye enters to play together with the contralateral synergist , that is , the inferior rectus muscle of the left eye . next to a moderate hypofunction of the right go , we noted the presence of an alteration of the om of different degrees in left ir . in fact , the lower rectus left eye showed , in 21.7% of cases , a severe hyperfunction this time ( score = + 3 ) . in addition , our sample showed an optimum operation of the inferior rectus muscle of the left eye in 60.9% and a moderate hypofunction in 8.7% with the same percentage of 4.4% of cases , and the ir of the left eye presented a mild and moderate hyperfunction . another gaze direction where we found an alteration of ocular motility is the one in the top right . we noticed the presence of a severe hypofunction of the right superior rectus muscle ( score = 3 ) observed in 30.5% of cases compared to 39.1% of cases who reported a normal function of this muscle . furthermore , in 17.5% of cases , the sr of the right eye showed a moderate hypofunction , 8.6% a severe hyperfunction , and a mild hypofunction of only 4.3% . for the diagnostic position of gaze in the top right , as well as , having experienced a severe hypofunction of the sr of the right eye , we also detected a hyperfunction of the same grade ( score = + 3 ) of the contralateral synergist muscle , that is , the small oblique of left eye with an incidence in 34.8% of cases . in 39.1% of the 23 individuals , however , the operation of the so of the left eye was optimal while 13% had a moderate hyperfunction , 8.7% a severe hypofunction , and 4.4% a mild hyperfunction . finally , we found the presence of an alteration of ocular motility in the gaze to the lower right . this alteration was found in the inferior rectus muscle of the right eye that showed a severe hyperfunction in 21.7% of cases and the same percentage of incidence equal to 4.4% of the cases for a mild hyperfunction and moderate hypofunction . instead in 69.5% of cases , the inferior rectus muscle of the right eye showed a normal operation . in the diagnostic position in the lower right corner , as well as in the gaze to the lower left , we noted the presence of an alteration in ocular motility of different degrees for contralateral synergist muscles . in fact , a severe hyperfunction ( score = + 3 ) of the ir of the right eye is associated with a moderate hypofunction ( score = 2 ) of large oblique muscle of the left eye in 17.5% of cases . taking into consideration the position of gaze , the go muscle of the left eye worked normally in 69.6% of cases , while it showed a severe hypofunction and moderate hyperfunction with the same percentage of 4.3% ( table 1 ) . through a pearson correlation , we can say that the contralateral synergist muscles being compared from the evaluation of ocular motility are inversely correlated , and this allows us to state that there is a direct relationship between the retinitis pigmentosa and ocular motility disorders ( table 2 ) . prime position muscle hypofunction mild hypofunction moderate hypofunction severe normal hyperfunction mild hyperfunction moderate hyperfunction severe . in the upper left : right inferior oblique 0 0 4.4% 34.7% 4.4% 17.4% 39.1%left superior rectus 4.3% 21.8% 30.5% 34.8% 0 0 8.6% . in the upper right : right superior rectus 4.3% 17.5% 30.5% 39.1% 0 0 8.6%left inferior oblique 0 8.7% 0 39.1% 4.4% 13% 34.8% . in the bottom left : right superior oblique 4.3% 21.8% 4.3% 61% 0 4.3% 4.3%left inferior rectus 0 8.7% 60.9% 0 4.4% 4.4% 21.7% . in the bottom right : left superior oblique 4.3% 17.5% 4.3% 69.6% 0 4.33% 0right inferior rectus 0 4.4% 0 69.5% 4.4% 0 21.7% . using the test cover , the evaluation of 25 patients examined with and without corrective lenses for near and evaluated for near ( by observing a target light ) and for far ( indicating a letter of the optotype in relation to the patient 's visual acuity ) showed interesting data . indeed , in our sample we have found the presence of a vertical deviation in 4 patients ; among these , 2 ( a patient with rp and one with s. of uscher ) reported a deviation l / r with and without the lens , and the other 2 ( a typical patient with rp and the other with atypical rp ) that reported a deviation r / l . considering the vertical deviation of the cover test examination , we found a l / r with an incidence of 8.69% and a r / l in 4.35% of cases tested for near with and without corrective lenses ( figure 3 ) . in the evaluation , however , for far ( with and without lens ) , the cover test has highlighted the presence of a r / l in 4.35% of the 23 individuals observed ; while in almost all of our sample ( 95.65% of cases ) ortoforia was present . this vertical deviation could justify the alteration of ocular motility observed in our rp sample , but the percentage is statistically insignificant . the data concerning the horizontal deviation highlighted with alternate cover test in the 25 patients evaluated with and without corrective lenses for near and far were 3 individuals during the dissociation cover test for near with lens showed no changes in refixation ( orthoforic subjects ) , while 5 patients had a recovery movement of the eye just discovered from the outside inwards ( exoforia ) . in cases of deviation greater than 2 pd , the angle of deviation has been measured with a prism with a base opposite to the direction of the deviation and assigning the + sign in the case of eso and the sign in the case of exo . the cover - uncover was essential to establish the quality of the deviation : if it is phoria or tropiaor if there is a recovery of deviation ( phoria - tropia ) and what is the fixing eye . we noted only one case of exotropia of the left eye of 16 pd and two cases of tropia - phoria of 14 pd . only in these 3 cases has there been an alteration of ocular motility directly proportional to the amount of deviation in the primary position . moreover , the presence of a case of esoforia of 8 pd and two cases of phoria - tropia , one of 10 pd and the other one of 6 pd , were found . in 6 patients , we found that 12 patients had no movements of refixation , 3 patients were exoforical , and 2 patients showed a phoria - tropia of 10 pd . there was only one case of a 15-year - old girl who , even without corrective lenses , had a tropia ( 16 pd ) . additionally , 3 patients had , respectively , anesoforia of 6 pd and anexoforia of 4 pd and 8 pd ( figure 5 ) . finally , in the ct evaluation with or without a lens for far , almost all of our sample did not show any significant horizontal deviation . in fact , the ct for distance with lens showed that 22 individuals did not show any deviation , and a tropia - phoria of 12 pd was found in a 15-year - old deaf and dumb girl who presented an exotropia to corneal reflexes . while always considering the ct for distance but without corrective lenses , we found in the same 15-year - old child a tropia - phoria of 14 pd and 3 cases of exoforia . most of our sample , however , showed no deviation ( 19 individuals out of 23 ) . the sample recruited showed a significant proportion of patients with pure retinitis pigmentosa ( 69.5% ) , and the remaining part was suffering from associated syndromes . from the assessment of ocular motility , it was evident that in no patient had an alteration of the medial rectus and lateral rectus muscles in left and right side gaze . it is instead essential to mention the presence of an ocular motility alteration for the small oblique , large oblique , superior rectus , and inferior rectus muscles in 50% of the sample . 39.1% of the sample has a severe hyperfunction of the small oblique muscle of the right eye and a severe hyperfunction ( 34.5% ) of the small oblique of the left eye ; 21.8% have a moderate hypofunction of the large oblique muscle of the right eye with a moderate percentage of hypofunction of 17.5% for the great oblique of the left eye ; 30.5% of the sample has , however , a percentage of 30.5% of severe hypofunction of both eyes ' superior rectus muscles ; 21.7% of the sample showed a hyperfunction of the inferior rectus muscle in both eyes . the results show that there is an impaired motility in 50% of patients in this inherited disorder . this alteration of the ocular motility is not , however , due either to a high refractive defect ( size medium - low myopia : 1 diopter 3 sd ) or to a binocular vision severely impaired ( visual acuity , motor fusion , and stereopsis are normal or within commonly accepted limit values ) . in fact , since rp is a genetically determined disease , the absence of eye movement disorders in the other 50% of the sample could be linked to the different penetrance of the disease that determines the existence of healthy carriers . therefore , the results of this study indicate that , in patients with rp , there is an alteration of ocular motility and this indicates that a careful orthotic screening may allow a further contribution to an early diagnosis especially in those cases of rp with family history and in healthy carriers .

purpose . we evaluated a sample of individuals with retinitis pigmentosa ( rp ) with the aim of assessing the presence or absence of ocular motility ( om ) disorders . materials and methods . we included 23 out of the 25 individuals from the sample ( 9 females and 14 males ) with an average visual acuity of 6/10 . results . the cover test about the vertical deviation in near distance showed an r / l in 3.45% and an l / r in 6.9% . the assessment of om showed that 39.1% of the sample had a severe hyperfunction of the io of the right eye and a severe hyperfunction ( 34.5% ) of the so of the left eye ; 21.8% had a moderate hypofunction of right so with a moderate percentage of hypofunction of 17.5% for the so of the left eye ; 30.5% , however , showed a serious hypofunction of the sr of both eyes ; 21.7% of the sample showed a hyperfunction in both eyes of the ir . conclusion . this alteration , however , is not attributable to either a high refractive defect ( medium - low myopia : 1 diopter 3 sd ) or to a severely impaired binocular vision ( visual acuity , motor fusion , and stereopsis are normal or within a range of values commonly accepted ) . therefore , the disorders of om lead to a genetic origin .

But that didn't stop Carmen and Shannon Wampler-Collins from successfully walking out of the Rowan County, Kentucky, clerk's office with a marriage license in hand. Monday was Davis' first day back in her office after spending five days in jail for defying a court order and refusing to give licenses to same-sex couples. Before starting her workday, Davis appeared defiant, saying she will not issue any marriage licenses that go against her religious beliefs. But she left the door open for her deputies to continue giving out marriage licenses to same-sex couples as long as those documents do not have Davis' name or title on them. The marriage license that the couple received said "pursuant to federal court order" on it, and instead of listing Davis' name and Rowan County, it says city of Morehead, the county seat. David said Monday that any such licenses "will not issued or authorized by me." Her work-around is not to sign them but not interfere with her deputies who do give them out. "(U.S. District Judge David Bunning) indicated last week that he was willing to accept altered marriage licenses even though he was not certain of their validity," Davis said. "I, too, have great doubts whether the license issued under these conditions are even valid." Yet one person without such doubts is Kentucky's governor. "I'm ... confident and satisfied that the licenses that were issued last week (and) this morning substantially comply with the law in Kentucky," Gov. Steve Beshear told reporters Monday. "And they're going to be recognized as valid in the Commonwealth." CNN senior legal analyst Jeffrey Toobin said that Kentucky law might allow for a deputy's signature to be valid on a marriage license, even without the clerk's consent. But if the documents are altered to remove Davis' name and title, a court may have to rule on their validity. Attorney: Clerk's office in an impossible position Davis' strategy is a "good faith" attempt to comply with the judge's ruling while at the same time not violate her conscience, her attorney Harry Mihet said at a news conference Monday. "Today, Kim Davis remains the bravest woman in America," Mihet said. "She has not compromised her conscience, she has not compromised her faith and she has not quit serving the people of Rowan County that she loves very much." He reiterated that although one of Davis' deputy clerks issued a license to a same-sex couple Monday, it was done so without her authorization. The modified marriage license that Carmen and Shannon Wampler-Collins received as well as the licenses issued while Davis was in jail do not have the clerk's authority, Mihet said. Including the license issued Monday, the clerk's office has issued 11 licenses since Davis went to jail September 3. Eight of those licenses have been for same-sex couples. "If any of her clerks decide that they must issue licenses to avoid going to jail, she will not take any adverse action against them," Mihet said, adding the clerk's office is caught in an impossible position. The modified marriage licenses are effectively in limbo, Mihet said, as it is unclear whether they are legal. Governor: No special session JUST WATCHED What does it mean to be in contempt of court? Replay More Videos ... MUST WATCH What does it mean to be in contempt of court? 01:24 Another Davis attorney, Mat Staver, said a solution would be to remove not just Davis' name and office from the marriage licenses themselves but from the process entirely. Have the state issue them instead, he said. Sounds simple enough, but under current Kentucky state law, the authority to issue marriage licenses rests solely with each of the state's 120 county clerks, meaning it would take an act of the legislature to transfer that authority. The legislature, however, doesn't convene until January 5. The state's governor, though, thinks "there is just no need to waste hundreds of thousands of dollars of taxpayers' money" by calling a special session. "If you want to change the way licenses are issued, ... they're free to do so," Beshear said of changes that could be made starting in January. "But I just don't see the urgency now." Since being released from jail last week, Davis has been keeping a low profile and opening boxes of letters sent to her while she was in jail. ||||| A new billboard that popped up along a busy Rowan County road has again drawn attention to the eastern Kentucky county ahead of embattled county clerk Kim Davis' expected return to work on Monday. "Dear Kim Davis," the billboard reads, "the fact that you can't sell your daughter for three goats and a cow means we've already redefined marriage." The non-profit organization Planting Peace paid for the billboard, which is visible from Flemingsburg Road in Morehead. "We put up this billboard just kind of reminding her that from a religious perspective, the definition of marriage has been constantly changing, and this isn't actually about religion," Davis Hammet, director of operations for the organization, told WKYT's Garrett Wymer over the phone. "We're talking about government-issued marriage licenses here." Planting Peace is the organization known for its rainbow-colored "Equality House" directly across the street from Westboro Baptist Church in Kansas. According to its website, the organization is a "global nonprofit organization founded for the purpose of spreading peace in a hurting world. Our projects focus primarily on humanitarian aid and environmental initiatives, including our multi-national deworming campaign, Equality House LGBTQ rights advocacy, a network of orphanages and safe havens, and conservation effort in the rainforests of Peru." Now the new billboard is getting a lot of attention as a new chapter is set to begin in the ongoing story of Kim Davis. Davis' attorneys said last week after she was released from jail that Davis would return to work at the Rowan County Clerk's office on Monday. On Friday, Davis' attorneys filed a new emergency stay motion in federal appeals court, asking for Judge Bunning's order for Davis to issue marriage licenses be thrown out. The motion says U.S. District Judge David Bunning expanded an injunction against Davis while it was already on appeal. It says that expansion went beyond the original plaintiffs without notice, violating a fundamental rule of due process. "The injunction against Kim Davis ordering her to issue marriage licenses cannot, without proper notice and briefing, be expanded to cover the entire world," said Mat Staver, Founder and Chairman of Liberty Counsel. "That original injunction is moot and should be dismissed. We are asking the court of appeals to stay its enforcement now that plaintiffs received what they sought." Davis objects to same-sex marriage for religious reasons and stopped issuing all marriage licenses in June after the U.S. Supreme Court legalized gay marriage. The ACLU filed a lawsuit against Davis, and Bunning later ordered Davis to issue the licenses. She refused to do it saying she could not betray her conscience. Bunning held Davis in contempt of court and sent her to jail for disobeying his order. Her deputy clerks then issued marriage licenses to gay couples, and Bunning released her September 8. Davis' attorneys released a statement that says Bunning broadened the expanded injunction "to cover anyone in the world who seeks a license for same-sex marriage." "Once the initial Injunction was appealed by Kim Davis to the Sixth Circuit Court of Appeals, Judge Bunning had no jurisdiction over it, and thus no authority, to expand the Injunction," the statement says, noting that the original injunction ordering her to issue marriage licenses "should be moot and dismissed because it applied only to the named plaintiffs who have no further claim." At a large rally outside the Carter County Jail on the day she was released, Davis' attorney said the fight for religious freedom is far from over. "You see, the problem is today the same as it was when this case began," Staver told the crowd that day. "She cannot allow her name to be associated with something that conflicts with God's definition of marriage." That's the message the folks behind the billboard say they're trying to counter. In a message posted on its website on Friday, the organization claims the intent of the billboard is to "expose this narrow interpretation by Davis and others that they use to defend their discrimination against the LGBTQ community." The organization also says it hopes the billboard can help encourage LGBTQ youth in Rowan County. "There are LGBTQ youth across the world who are taking their lives at an alarming rate because of these messages from society that make them feel broken or less than," Planting Peace President Aaron Jackson said in a statement sent to WKYT on Saturday afternoon. "We have to meet hate with love, intolerance with compassion. Our message to our LGBTQ youth is simple: You are loved, valued, supported, and beautiful. There is nothing wrong with you, and we will stand by you. You are not alone." Hey, Kim! Have you received our note yet? Sincerely, Planting Peace. <3 http://t.co/u8sqyvt7zz pic.twitter.com/3kZhHNBzEl — Planting Peace (@Planting_Peace) September 11, 2015 FULL STATEMENT FROM PLANTING PEACE PRESIDENT AARON JACKSON: "The intent of this billboard is to expose how the anti-LGBT movement is selective in what rules to follow and how they choose to define "traditional" institutions or values. It's important and relevant to call this out, because the actions of Kim Davis and the messages from the anti-LGBTQ movement are not simply about a political or religious debate. There are LGBTQ youth across the world who are taking their lives at an alarming rate because of these messages from society that make them feel broken or less than. We have to meet hate with love, intolerance with compassion. Our message to our LGBTQ youth is simple: You are loved, valued, supported, and beautiful. There is nothing wrong with you, and we will stand by you. You are not alone." ||||| CLOSE Kim Davis was released from jail on the condition that she not "interfere" with her deputy clerks' efforts to issue marriage licenses to same-sex couples. The Kentucky clerk spent five nights in jail for contempt of court. VPC Billboard erected in Kim Davis' hometown (Photo: Planting Peace) A non-profit organization that advocates for LGBTQ rights has a big message for Rowan County (Kentucky) clerk Kim Davis — a message that is the size of a billboard, to be exact. Planting Peace erected a billboard in Davis' hometown of Morehead, Ky., that reads: "Dear Kim Davis, The fact that you can't sell your daughter for three goats and a cow means we've already redefined marriage." Aaron Jackson, president of Planting Peace, told USA TODAY that the intent of the billboard is to "expose how the anti-LGBT movement is selective in what rules to follow and how they choose to define 'traditional' institutions or values." Davis came into the spotlight this month after she refused to issue marriage licenses to gay couples on the grounds of her religious beliefs, despite the Supreme Court's 5-4 landmark ruling that legalized same-sex marriage earlier this year. Davis, an elected official was jailed last week for defying the court and was released on Tuesday after several same-sex couples received marriage licenses from the clerk's office while Davis was in jail. However, Davis, who returns to work Monday, could face sanctions if she again interferes with eligible couples receiving licenses. Billboard erected in Kim Davis' hometown of Morehead, Ky. (Photo: Planting Peace) Will Davis see the billboard? Quite possibly. It is placed in the middle of a long road in the rural town of 7,000 people and will be erected for one month. "We have been told members of the local community have been taking photos and selfies in front of the billboard," Jackson said. "We are excited that they've embraced our message." Planting Peace is the same group that launched the Equality House in 2013, a rainbow-painted house across from the Westboro Baptist Church in Topeka, Kan., where a lesbian couple held their wedding. Follow USA TODAY reporter Trisha Thadani on Twitter: @TrishaThadani Read or Share this story: http://usat.ly/1UOwPtg ||||| Play Facebook Twitter Embed County clerk Kim Davis set to return to work 1:52 autoplay autoplay Copy this code to your website or blog The Kentucky clerk who was jailed after refusing to issue marriage licenses to same-sex couples hasn't exactly gotten the warmest welcome in her hometown after her release. A billboard defending gay marriage, towering high above a Rowan County road, is directed specifically at Kim Davis. Planting Peace, the nonprofit humanitarian organization that paid for the billboard, said in a statement that the "intent of the billboard is to expose this narrow interpretation by Davis and others that they use to defend their discrimination against the LGBTQ community." "Dear Kim Davis, the fact that you can't sell your daughter for three goats and a cow means we've already redefined marriage," the billboard reads. “ There are LGBTQ youth across the world who are taking their lives at an alarming rate because of these messages from society that make them feel broken or less than.” The message appears to refer to a Bible scripture that says women can be sold into marriage as slaves. Planting Peace said they are pointing out that "a substantial number of zealots" cite their religion as a reason for disagreeing with gay marriage while ignoring other parts of the Bible that many consider equally antiquated. Play Facebook Twitter Embed Billboard Mocks Kim Davis 0:58 autoplay autoplay Copy this code to your website or blog Planting Peace president Aaron Jackson told NBC News that the billboard cost $500 and will stay up for a month. “The anti-LGBT movement is selective in what rules to follow and how they choose to define ‘traditional’ institutions or values,” Jackson said. After the Supreme Court's ruling in late June that the Constitution guarantees gay couples the right to get married, Davis continued to deny gay couples marriage licenses. She said it went against her Apostolic Christian beliefs to do so. Davis tried to appeal numerous orders to issue the licenses, and remained steadfast in her vow not to tender the same-sex marriage licenses when her appeals were denied. Her stance landed her in jail on contempt of court charges, but she was released Tuesday because her office was issuing the licenses in her absence. Davis has said she will return to work Monday, and her lawyer said she will find a way to avoid issuing marriage licenses to same-sex couples. Check out this new billboard from our friends at @Planting_Peace http://t.co/u87aKUAhlA pic.twitter.com/5iCIc0Su8Q — NOH8 Campaign (@NOH8Campaign) September 12, 2015 Davis has garnered a number of supporters, and said in a statement Wednesday that she received "hundreds and hundreds" of letters of people who agree with her decision. Planting Peace contends that praising Davis sends a dangerous message to the gay community. "We have to meet hate with love … intolerance with compassion," the organization said in their statement. "There are LGBTQ youth across the world who are taking their lives at an alarming rate because of these messages from society that make them feel broken or less than." Jackson said Planting Peace is hoping to convey something very simple to LGBTQ youth: “You are loved, valued, supported, and beautiful. There is nothing wrong with you, and we will stand by you. You are not alone.” Planting Peace doesn't only focus on LGBT rights, but has opened six international orphanages, treated children with intestinal parasites all over the world, according to their website. A rainbow-adorned house across the street from Westboro Baptist Church in Kansas is probably Planting Peace's best-known project. "Equality House" serves as the nonprofits headquarters for anti-bullying initiatives and has been the site of a gay wedding and a young girl's "lemonade stand for peace."

– Kim Davis is probably going back to work today, and there's a good chance that the Kentucky county clerk will pass a billboard with her name on it on the way in. The nonprofit group Planting Peace has paid for a large ad reading: "Dear Kim Davis, the fact that you can't sell your daughter for three goats and a cow means we've already redefined marriage," apparently referring to an Old Testament verse, NBC News reports. In a statement, the group said it's highlighting the way some anti-gay "zealots" use "their rigid interpretation of religious text to narrowly define 'traditional' institutions and values," picking and choosing some parts of Scripture while ignoring others. "We put up this billboard just kind of reminding her that from a religious perspective, the definition of marriage has been constantly changing, and this isn't actually about religion," a Planting Peace spokesman tells WKYT. "We're talking about government-issued marriage licenses here." The group paid $500 to put the billboard up for a month on a major road in Morehead, Davis' hometown, USA Today reports. Davis could end up back in jail if she refuses to grant marriage licenses to same-sex couples today, and her lawyer tells CNN he's not sure what she plans to do. (In 2013, the group behind the billboard bought a house across the street from the Westboro Baptist Church and painted it in rainbow colors.)

SECTION 1. SHORT TITLE. This Act may be cited as the ``Public Schools Renewal and Improvement Act of 1997''. SEC. 2. FINDINGS AND PURPOSE. (a) Findings.--The Congress finds the following: (1) Although the majority of our Nation's elementary and secondary public schools provide high quality education for our children, many schools need additional resources to implement immediate assistance and reform to enable them to provide a basic and safe education for their students. (2) The Government Accounting Office recently found that \1/3\ of all elementary and secondary schools in the United States, serving 14,000,000 students, need extensive repair and renovation. (3) Recent reform of under-achieving schools in a number of States and school districts demonstrates that parents, teachers, school administrators, other educators, and local officials, given adequate resources and expertise, can succeed in dramatically improving public education and creating high performance schools. (4) Such reform efforts show that parental and community involvement in those reforms is indispensable to the objective of high quality, safe, and accountable schools. (5) Despite the successes of such reforms, public schools are facing tremendous challenges in educating children for the 21st century. The elementary and secondary school population will grow by 10 percent by the year 2005, and over the next 10 years, schools will need more than 2,000,000 additional teachers to meet the demands of such expected enrollments. (6) Almost 7 of 10 Americans support increased Federal assistance to our Nation's public schools, and that support crosses all boundaries, including cities, towns, and rural areas. (7) When Federal investment in public schools and children has increased, test scores have improved, and high school graduation rates and college enrollments have increased. (8) The Federal Government should encourage communities that demonstrate a strong commitment to restore and reform their public schools. (b) Purpose.--It is the purpose of this Act to assist local communities that are taking the initiative-- (1) to overcome adverse conditions in their public schools; (2) to revitalize their public schools in accordance with local plans to achieve higher academic standards and safer and improved learning environments; and (3) to ensure that every community public school provides a quality education for all students. SEC. 3. DEFINITIONS. For purposes of this Act: (1) Consortium.--The term ``consortium'' means a local schools consortium as defined in paragraph (2). (2) Local schools consortium.--The term ``local schools consortium'' means the local educational agency in collaboration with a group composed of affected parents, students, and representatives of teachers, school employees and administrators, local business and community leaders and representative of local higher education group working or residing within the boundary of a local educational agency. (3) Parent.--The term ``parent'' includes any of the following: (A) A grandparent. (B) A legal guardian. (C) Any other person standing in loco parentis. (3) Plan.--The term ``plan'' means a 3-year public schools renewal and improvement plan described in section 5. (4) Secretary.--The term ``Secretary'' means the Secretary of Education. (5) State.--The term ``State'' means each of the 50 States, the District of Columbia, the Commonwealth of Puerto Rico, the American Virgin Islands, Guam, and American Samoa. SEC. 4. PROCEDURE FOR DECLARATION. (a) In General.--A request for a declaration by the President that a ``public schools renewal effort is underway'' shall be made by a local schools consortium. (b) Request.--The local education agency shall submit the request to the Governor of the State who shall, with or without comment, forward such request to the President not more than 30 days after the Governor's receipt of such request. Such request shall-- (1) include the plan; (2) describe the nature and amount of State and local resources which have been or will be committed to the renewal and improvement of the public schools; and (3) certify that State or local government obligations and expenditures will comply with all applicable matching requirements established pursuant to this Act. (c) Declaration.--Based on a request made under this Act, the President, in consultation with the Secretary, may declare that a ``public schools renewal effort is underway'' in such community and authorize the Department of Education and other Federal agencies to provide assistance under this Act. (d) Progress Reports.--The consortium shall-- (1) amend such request annually to include additional initiatives and approaches undertaken by the local educational agency to improve the academic effectiveness and safety of its public school system. (2) submit annual performance reports to the Secretary which shall describe progress in achieving the goals of the plan. SEC. 5. ELEMENTS OF RENEWAL AND IMPROVEMENT PLAN. (a) In General.--As part of its request to the President, and in order to receive assistance under this section, a consortium shall submit a plan that includes the elements described in subsections (b) and (c). (b) Adverse Conditions.--The plan shall specify the existence of any of the following factors: (1)(A) A substantial percentage of students in the affected public schools have been performing well below the national average, or below other benchmarks, including State developed benchmarks in such basic skills as reading, math, and science, consistent with Goals 2000 and title I of the Elementary and Secondary Education Act of 1965; or (B) a substantial percentage of such students are failing to complete high school. (2) Some or all of such schools are overcrowded or have physical plant conditions that threaten the health, safety, and learning environment of the schools' populations. (3) There is a substantial shortage of certified teachers, teaching materials, and technology training. (4) Some or all of the schools are located where crime and safety problems interfere with the schools' ability to educate students to high academic standards. (c) Assurances.--The plan shall also include assurances from the local educational agency that-- (1) the plan was developed by the local schools consortium after extensive public discussion with State education officials, affected parents, students, teachers and representatives of teachers and school employees, administrators, higher education officials, other educators, and business and community leaders; (2) describe how the consortium will use resources to meet the types of reforms described in section 7; (3) provide effective opportunities for professional development of public school teachers, school staff, principals, and school administrators; (4) provide for greater parental involvement in school affairs; (5) focus substantially on successful and continuous improvement in the basic academic performance of the students in the public schools; (6) address the unique responsibilities of all stake holders in the public school system, including students, parents, teachers, school administrators, other educators, governmental officials, and business and community leaders, for the effectiveness of the public school system especially with respect to the schools targeted for greatest assistance; (7) provide for regular objective evaluation of the effectiveness of the plan; (8) the agency will give priority to public schools that need the most assistance in improving overcrowding, physical problems and other health and safety concerns, readiness for telecommunications equipment, and teacher training and the pool of certified teachers; (9) ensure that funds received under this Act shall be used to supplement, not supplant other non-Federal funds; (10) certify that the combined fiscal effort per student or the aggregate expenditures within the State with respect to the provision of free public education for the fiscal year preceding the fiscal year for which the request for a declaration is made was not less than 90 percent of such combined fiscal effort or aggregate expenditures for the second fiscal year preceding the fiscal year for which the request for a declaration is made; and (11) will address other major issues which the local schools consortium determines are critical to renewal of its public schools. SEC. 6. ALLOWABLE FEDERAL ASSISTANCE. (a) In General.--To provide assistance under this Act, the President may-- (1) direct the Department of Education, with or without reimbursement, to use the authority and the resources granted to it under Federal law (including personnel, educational equipment and supplies, facilities, and managerial, technical, and advisory services) in support of State and local assistance efforts; (2) direct any other Federal agency to provide assistance as described in paragraph (1); (3) coordinate such assistance provided by Federal agencies; and (4) provide technical assistance and advisory assistance to the affected local educational agency. (b) Distribution of Assistance Funds.-- (1) In general.--At the direction of the President, the Secretary shall distribute funds and resources provided pursuant to a declaration under this Act to local educational agencies selected for assistance under this Act. (2) Existing procedures.--The Secretary shall determine the best method of distributing funds under this Act through personnel and existing procedures that are used to distribute funds under other elementary and secondary education programs. (c) Prohibition.--No provision of this Act shall be construed to authorize any action or conduct prohibited under the General Education Provisions Act. SEC. 7. USE OF ASSISTANCE. Assistance provided pursuant to this Act may be used only to carry out a plan, and to effectuate the following and similar types of public school reforms: (1) Student-Targeted Resources.-- (A) Increasing and improving high-quality early childhood educational opportunities. (B) Providing comprehensive parent training so that parents better prepare children before they reach school age. (C) Establishing intensive truancy prevention and dropout prevention programs. (D) Establishing alternative public schools and programs for troubled students and dropouts, and establishing other public school learning ``safety nets''. (E) Enhancing assistance for students with special needs (including limited English proficient students, English as a second language, and students with disabilities). (2) Classroom focused school development.-- (A) Establishing teacher and principal academies to assist in training and professional development. (B) Establishing effective training links for students with area colleges and universities. (C) Establishing career ladders for teachers and school employees. (D) Establishing teacher mentor programs. (E) Establishing recruitment programs at area colleges and universities to recruit and train college students for the teaching profession. (F) Establishing stronger links between schools and law enforcement and juvenile justice authority. (G) Establishing stronger links between schools and parents concerning safe classrooms and effective classroom activities and learning. (H) Establishing parent and community patrols in and around schools to assist safe schools and passage to schools. (I) Implementing research-based promising educational practices and promoting exemplary school recognition programs. (J) Expanding the time students spend on school- based learning activities and in extracurricular activities. (3) Accountability reforms.-- (A) Establishing high learning standards and meaningful assessments of whether standards are being met. (B) Monitoring school progress and determining how to more effectively use school system resources. (C) Establishing performance criteria for teachers and principals through such entities as joint school board and union staff improvement committees. (D) Establishing promotion and graduation requirements for students, including requirements for reading, mathematics, and science performance. (E) Providing for strong accountability and corrective action from a continuum of options, consistent with State law and title I of the Elementary and Secondary Education Act of 1965. SEC. 8. DURATION OF ASSISTANCE. Assistance under this Act may be provided for each of fiscal years 1998 through 2000. SEC. 9. REPORT. Not later than March 31, 2000, the Secretary shall submit a report to the Committee on Education and the Workforce of the House of Representatives and the Committee on Labor and Human Resources of the Senate assessing the effectiveness of this Act in assisting recipient local schools consortia in carrying out their plans submitted under this Act. SEC. 10. AUTHORIZATION OF APPROPRIATIONS; MATCHING REQUIREMENT. (a) Authorization.--There are authorized to be appropriated to carry out this Act-- (1) for fiscal year 1998, $250,000,000; and (2) for fiscal year 1999, $500,000,000; and (3) for fiscal year 2000, such sums as may be necessary. (b) Matching Requirement.-- (1) In general.--Federal funds expended or obligated under this Act shall be matched (in an amount equal to such amount so expended or obligated) from State or local funds. (2) Other federal resources.--The Secretary shall, by regulation and in consultation with the heads of other Federal agencies, establish matching requirements for other Federal resources provided under this Act. (3) Waiver.--Based upon the recommendation of the Secretary, the President may waive paragraph (1) or (2).

Public Schools Renewal and Improvement Act of 1997 - Establishes a procedure by which a local schools consortium shall request, through the State Governor, a declaration by the President that a public schools renewal effort is underway in its community. Requires such request to: (1) include the three-year plan for public schools renewal and improvement; (2) describe the nature and amount of State and local resources which have been or will be committed to such renewal and improvement; and (3) certify that State or local government obligations and expenditures will comply with all applicable matching requirements established pursuant to this Act. Authorizes the President to: (1) make such a requested declaration; and (2) authorize the Department of Education and other Federal agencies to provide assistance under this Act. Requires the consortium to make annual: (1) amendments to the request to include additional initiatives and approaches to improve academic effectiveness and school safety; and (2) progress reports to the Secretary of Education. (Sec. 5) Sets forth required elements of such public schools renewal and improvement plans, including specification of certain adverse conditions and certain assurances. (Sec. 6) Authorizes the President to provide for various forms of allowable Federal assistance under this Act. Directs the Secretary to distribute such funds and resources. (Sec. 7) Sets forth requirements for use of such assistance for various student-targeted resources, classroom-focused school development, accountability reforms, and other, similar types of public school reforms. (Sec. 8) Allows such assistance to be provided for each of FY 1998 through 2000. (Sec. 9) Requires the Secretary to report to specified congressional committees on this Act's effectiveness. (Sec. 10) Authorizes appropriations. Sets forth matching requirements for States or localities, which the President may waive upon the Secretary's recommendation.

PHOENIX An Arizona man was arrested on suspicion of animal cruelty after hundreds of dying or dead domesticated rats were found inside a large trailer north of Phoenix, authorities said on Tuesday. Jeffrey Wendorff, 28, was arrested by Yavapai County sheriff's deputies on Monday and could face two misdemeanor charges since the discovery in Black Canyon City, about 50 miles from Phoenix. Arriving deputies and animal control officers could immediately smell a stench from the property and discovered 300 to 500 rats in a pen in the back of the trailer and several others in a front area, said sheriff's spokesman Dwight D'Evelyn. "The temperature inside the trailer was over 100 degrees and the odor was overwhelming," D'Evelyn said in a statement. He estimated that about 25 percent of the animals were dead. Authorities said they were tipped to the gruesome scene by a citizen who called the county health department after seeing the rats in and around the large travel trailer. Deputies also found several aquariums with newborn and adult rats that appeared to be in good condition. Wendorff told sheriff's deputies he was living on the property rent free as part of a deal with the property owner to breed and sell the rats. He also said he stopped caring for the rodents recently and had left the residence over a pay dispute, telling deputies, "As far as I know, (the rats are) probably all dead." Wendorff has since been released from a county detention center and is due in court at a future date that was not immediately known, D'Evelyn said. (Reporting by David Schwartz in Phoenix; Editing by Eric M. Johnson and Michael Perry) ||||| Jul 1, 2014 8:26 PM by Marissa Esquivel Yavapai County man accused of animal cruelty to rats YAVAPAI COUNTY - A Yavapai County man has been arrested and charged with animal cruelty charges. On Monday, Yavapai County Health Services got a call from a citizen reporting numerous dying and dead rats in and around a trailer on the property. When deputies arrived, they immediately smelled urine, feces and dead animal carcass' emanating from the property. The trailer had a cage in the front section with several dead rats. Other cages near the end of the trailer had 300-500 rats, most of which where dead. Inside the main house, deputies found aquariums with newborn and adult rats, which appeared to be in good condition. Sheriff deputies said the temperature inside the trailer was over 100 degrees and the odor was overwhelming. Deputies were able to determine that 28-year-old Jeffrey Wendorff was the caretaker of rats. He was located at a nearby business and detained. Wendorff first denied any knowledge of animals on the property. Eventually, he admitted that he had stopped caring for the rats. Wendorff said he was living at the location until a couple of weeks ago. Both he and the property owner had previously entered into a business partnership, breeding and selling rats. Wendorff told duputies that the arrangement allowed him to live on the property for free. Following a money dispute, Wendorff abandoned his duty as the primary caretaker, moved, and abandoned the animals. Wendorff was arrested and charged with Cruel Mistreatment of Animals and Cruel Neglect/Abandonment of Animal, both misdemeanors. He was booked at the Camp Verde Detention Center and has since been released on a promise to appear for court.

– It was a scene whose appearance was likely rivaled only by its smell: An Arizona man is facing animal cruelty charges after Yavapai County sheriff’s deputies, acting on a tip, discovered scores of dead or dying rats in and around a trailer, Reuters reports; a pen in the trailer's rear contained as many as 500 rats. Roughly a quarter were dead, said a sheriff’s department rep. When they and animal control officers arrived at the scene Monday, deputies were welcomed by the "overwhelming" stench of feces, urine, and decomposition, adds KVOA; the temperature inside the trailer was reportedly over 100 degrees. Newborn and adult rats found in a number of aquariums that contained food and water appeared fine, reports the Arizona Republic. Jeffrey Wendorff, 28, who according to KVOA initially denied that he knew about the rats’ presence, was arrested on suspicion of cruel mistreatment of animals and cruel neglect and abandonment of an animal. Deputies say he ultimately admitted that he lived on the property rent-free in exchange for breeding the rats, but that his relationship with the property owner soured over money, causing him to take off a couple weeks ago, leaving the animals to their own devices. "As far as I know, (the rats are) probably all dead,” he told deputies. (Earlier this year, hundreds of dying snakes were found in a "house of horrors.")

a beagle dog treated with saline as a control animal in a preclinical study was euthanized due to sudden systemic deterioration . on histopathological examination , contraction band necrosis of myocardial cells was observed widely in the left ventricular wall , including the papillary muscle and apex , and observed slightly in the ventricular septum and left atrium . in the brain , necrosis was observed in neurons and glia of the cerebral cortex , hippocampal pyramidal cells , glial cells of the rostral commissure and purkinje cells of the cerebellar vermis . it is highly probable that the marked systemic deterioration was caused by cardiac dysfunction due to the spontaneous contraction band necrosis of the myocardial cells , although the pathogenesis of the myocardial lesions remains unclear . given the distribution of neuronal necrosis in the brain , it is likely that these lesions resulted from the ischemia responsible for acute cardiac failure .

given the 1:500 prevalence of hypertrophic obstructive cardiomyopathy ( hocm ) in the general population , it may present to the anaesthesiologist more often than anticipated . we hereby describe how our anaesthetic technique ( general anaesthesia with peripheral nerve blocks ) for bilateral knee arthroplasty was well chosen for the perioperative management of such a patient . a 69-year - old female weighing 78 kg , a medically managed ( atenolol 25 mg and amlodipine 10 mg once daily ) case of hocm was scheduled for bilateral knee arthroplasty . there was no history of angina , syncopal attacks , or any sudden death in her family . systemic examination revealed a regular pulse rate of 68 beats / min , and a grade 3/6 crescendo - decrescendo systolic murmur was heard between the left sternal border and apical area , not radiating to the carotids . electrocardiography ( ecg ) showed normal sinus rhythm with nonspecific t wave changes in leads ii , iii , and avf with left ventricular hypertrophy and left axis deviation . echocardiography showed asymmetrical septal hypertrophy , left ventricular outflow tract obstruction ( lvot ) with peak systolic gradient ( psg ) of 56 mmhg , moderate mitral regurgitation and moderate diastolic dysfunction with ejection fraction of 56% . both cardiac drugs were continued till the morning of surgery along with a premedication of oral ranitidine 150 mg and alprazolam 0.25 mg . in the operating room , baseline blood pressure ( bp ) , heart rate ( hr ) and respiratory rate ( rr ) were 160/90 mmhg , 68/minute and 14/minute , respectively . the patient was given injection metoprolol 2 mg , 80 mcg fentanyl and midazolam 2 mg intravenously , before establishing invasive monitoring ( left radial blood pressure and right jugular venous pressure ) , opening central venous pressure ( cvp ) was 8 mmhg . a bolus of 8 ml of 2% lignocaine with 8 ml of 0.2% ropivacaine was injected in each femoral catheter before the incision of each side , followed by a continuous infusion of ropivacaine 0.2% 8 ml / hour intra and postoperatively . half an hour later , induction and intubation were accomplished using propofol 100 mg , morphine 8 mg , midazolam 1 mg and vecuronium 8 mg . mild hypotension occurred with bp falling to 100/50 mmhg , which was managed with a bolus of 200 ml crystalloid and injection phenylephrine 50 g . to prevent intubation stress , esmolol anaesthesia was maintained with 66% nitrous oxide in oxygen and isoflurane 0.2 - 0.4% ( because of its myocardial depressive properties , halothane is an ideal agent in such patients but due to its nonavailability in our institute , isoflurane was used without any adverse haemodynamic changes ) ; the average duration of both tourniquets was 35 to 40 minutes . at the time of both tourniquet deflations , systolic pressures dropped by more than 20% each time which responded to a judicious administration of crystalloid and phenylephrine 100 mcg . cvp remained between 8 and 10 mmhg and urine output was 500 ml with an input of 2.5 l of crystalloids . the surgery lasted for four hours ; neuromuscular blockade reversed with neostigmine 3.5 mg and glycopyrrolate 0.6 mg and esmolol 30 mg was given again to prevent exaggerated haemodynamic response at extubation . post extubation , the patient was haemodynamically stable ( bp : 124/62 mmhg , hr : 74/minute ) with saturation of 100% on oxygen of 2 l / minute . postoperatively , the patient was transferred to a special intensive care unit ( icu ) for further management . four hours later , we noted increase in heart rate upto 94 - 96 beats/ min ; bp was 110/75 mmhg , cvp and rr were10 mmhg and 33/ min respectively and desaturation up to 90% on room air , with bilateral drain loss of about 100 ml each . her pain assessment on a verbal analogue score was 6 ( on a scale of 0 - 10 ) . immediately , the oxygen was increased from 2 to 5 l / minute . for pain and tachycardia , a bolus of ropivacaine 0.2% , 8 ml was given through each femoral catheter along with metoprolol 2 mg intravenously , and liberal fluids continued . also , other parenteral analgesics like diclofenac , paracetamol and tramadol were started on a regular basis , as per our icu protocol . six hours postoperatively , dyspnoea persisted with the occurrence of bilateral fine crepts in chest now and cvp increased to 12 mmhg with heart rate and bp being 88 - 90 beats / min and 108/70 mmhg , respectively . so , furosemide 20 mg and another dose of metoprolol 2 mg were given intravenously . the patient passed about 1200 ml urine over the next three hours ; her tachycardia and tachypnoea both settled with an hr of 78/minute and rr of 20/minute and blood pressure increased to 136/67 mmhg . her daily dose of atenolol was increased from 25 mg once a day to 50 mg orally twice a day . forty - eight hours later , the patient was shifted from the icu after removing femoral catheters . hocm is marked by asymmetric hypertrophy of the left ventricle ( left ventricular wall thickness > 15 mm ) , dynamic lvot obstruction due to systolic anterior motion of anterior valve leaflet of mitral valve and diastolic dysfunction caused due to impaired relaxation of noncompliant left ventricle.the patient may present from infancy to older than 90 years . although adverse clinical consequences of the disease , particularly sudden cardiac death , are well documented , a more balanced perspective regarding prognosis has recently evolved in which normal longevity is seen with relatively mild disability . a symptomatic patient may experience progressive heart failure with exertional dyspnoea , fatigue and chest pain , evolution to end - stage phase and atrial fibrillation ( af ) . goals of anaesthetic management should aim at avoiding exacerbation of outflow tract obstruction ( due to sympathetic stimulation ) , maintaining diastolic filling by maintenance of sinus rhythm and preventing fall in preload and afterload . centroneuraxial blocks , though not absolutely contraindicated , are still best avoided , because of the risk of profound bilateral sympathectomy and hypotension . though isolated measurements of cvp do not provide an accurate guide to left ventricular filling because of poor left ventricular compliance , serial recordings provide a useful trend . whenever sympathetic shootups were anticipated establishment of femoral nerve catheter and invasive lines , intubation and extubation good sedoanalgesia and adequate anaesthetic depth was provided with the beta blocker , esmolol . vasopressor phenylephrine was used as it increases systemic vascular resistance without ionotropy or chronotropy . for postoperative analgesia , our choice of continuous femoral nerve blocks ( cfnbs ) has many advantages over epidural analgesia like lack of hypotension and epidural haematoma associated with the use of anticoagulants , effective pain relief and improved functional recovery . till date , we have not found much literature on bilateral safe infusion doses of ropivacaine in peripheral nerve block for prolonged durations . our limitation is that we did not do serum values of ropivacaine because of lack of this facility in our institute . however , no signs or symptoms of toxicity were seen with our doses and patient satisfaction was good . according to standard teaching , sudden cardiac death is the most feared complication in perioperative setup , but maron et al . proposed two forms of disease , early onset and late onset . hocm in the elderly is less severe and has a more benign course , unlike the early onset of the disease in young adults , where more lethal complications like sudden cardiac death is seen . found congestive heart failure ( chf ) to be the predominant complication in elderly patients in the perioperative setup . this is related to diastolic dysfunction in hocm which causes increased diastolic filling pressures , pulmonary congestion and dyspnoea which is seen in 90% of the patients of hocm . the chief complaint of our patient , who was elderly , was also dyspnoea . focusing only on the lvot gradient and providing fluids aggressively may very well surpass the limits of cardiac compensation and precipitate chf . in our patient also , initial attempts to decrease ventricular gradient were fruitful to some extent by using beta blockers and local anaesthetic boluses for pain , but liberal fluids and diastolic dysfunction tipped the balance towards failure ( desaturation and tachypnoea ) , which finally responded to the diuretic . at this stage , if epidural boluses had been given instead of femoral , the resulting hypotension and tachycardia would have complicated the picture . hence , our choice of postoperative analgesia was well chosen . in conclusion , we do need to understand hocm pathophysiology and prevent exacerbation of lvot obstruction , but recent literature shifts our focus from catastrophic obstructive complications like perioperative sudden cardiac death in young hocm to more benign anaesthetic course in elderly hocm .

this case report exemplifies how the anaesthetic technique of general anesthesia with continuous bilateral femoral nerve block for bilateral knee arthroplasty was well chosen for the management of perioperative complications in an elderly patient with hypertrophic obstructive cardiomyopathy ( hocm ) . a 69-year - old female patient of hocm was scheduled for bilateral total knee replacement . echocardiography revealed severe left ventricular outflow tract obstruction with peak systolic gradient of 56 mmhg . the surgery was conducted under general anaesthesia with invasive monitoring and bilateral continuous femoral nerve blocks for postoperative analgesia . postoperatively , she developed pulmonary oedema due to the liberal administration of fluids . this complication was successfully managed without interrupting the management of pain . management of patients with hocm for noncardiac surgery requires knowledge of variable presentation of two forms of disease . also , this case report highlights the practical advantage of continuous femoral nerve block ( cfnb)s over epidural anaesthesia .

the low lying @xmath6 ev ) state @xcite of the @xmath2th nucleus has been the subject of intense experimental @xcite and theoretical research @xcite in the past decades . the interest is caused by new possibilities which are emerging in the study of such unusual nuclear level . the works on this problem are multidisciplinary , including fields of science as diverse as nuclear physics , solid state physics , atomic physics , optics and laser physics . three excellent experiments , refs . @xcite , which gave us the knowledge on the existence of the low - lying isomeric state and provided with estimations of its energy , demonstrate the variety of experimental methods needed for the characterization of this state . the experimental technique gradually evolves from traditional methods of nuclear spectroscopy @xcite to those used in low energy physics : solid state physics , optics , etc . @xcite . in a number of theoretical publications authors have drawn attention to exciting possibilities related with the existence of the @xmath7 ev ) state and its decay channels . here one can mention a refinement of some fundamental laws and symmetries of nature , for example , the cp - violation , the variation of the fine structure constant @xcite , the local lorentz invariance and the einstein equivalence principle @xcite . unusual for traditional nuclear physics decay channels of the isomeric state the electron bridge @xcite and nuclear light @xcite probably imply that the @xmath7 ev ) state can be occupied by laser emission through nuclear photo - excitation process @xcite or inverse electron bridge @xcite . an interesting consequence of such excitations is the detection of the @xmath8decay of the isomeric state @xcite with the possibility of checking the exponentiality of the decay law of an isolated metastable state at long times @xcite . finally , we should mention two important technological applications the nuclear clock @xcite , and the gamma - ray laser of the optical range @xcite , both of which can lead to a breakthrough in their fields . in the present study we have carried out calculations and give numerical estimations for the position of the sublevels of the @xmath9 and @xmath10 ev ) states in the highly charged ions @xmath2th@xmath3 and @xmath2th@xmath4 . the th@xmath3 ion has one electron which occupies the @xmath11 electron shell , while the th@xmath4 ion has three electrons on the @xmath11 and @xmath12 electron shells , i.e. the @xmath13 electron configuration . we have taken into account the bohr - weisskopf effect and the mixing of the states , and calculated the probabilities of the transitions between the sublevels . our calculations can be instrumental in experimental studies of the magnetic hyperfine ( mhf ) interaction in highly ionized atoms investigated in a storage ring of accelerator complex @xcite . a preliminary ( and as a rule , overestimated ) estimation of the mhf interaction can be obtained by using the fermi contact interaction @xcite . the electron in the @xmath11 state of the @xmath2th@xmath3 ion or electron in the @xmath12 state of the @xmath2th@xmath4 ion result in a strong magnetic field at the center of the @xmath2th nucleus @xcite . the value of this field is given by the formula for the fermi contact interaction ( see in @xcite ) @xmath14 where @xmath15 is the bohr magneton , @xmath16 is the electron charge , @xmath17 is the electron mass , @xmath18 are the pauli matrixes , and @xmath19 is the amplitude of the electron wave function at the origin . the interaction of the point magnetic moment of the ground state ( @xmath20 ) or the isomeric state ( @xmath21 ) of the @xmath2th nucleus with the magnetic field ( [ eq : h ] ) leads to a splitting of the nuclear levels . the energy of the sublevels is determined by the formula @xmath22 with the interaction energy @xmath23 here @xmath24 is the nuclear magneton ( @xmath25 is the proton mass ) , @xmath26 stands for the nuclear spin , @xmath27 is the electron spin . the quantum number @xmath5 takes two values @xmath28 for both the ground and isomeric state . to obtain the magnetic field and the hyperfine splittings one has to find the amplitude of the electron wave function at the nucleus , @xmath19 , eq . ( [ eq : h ] ) . the details of the calculations of @xmath19 are given in the next section . for precise determination of @xmath19 the calculations should be self - consistent , relativistic and take into account the finite size of the nucleus . in the present work , the wave function @xmath29 of the electron in the @xmath30 configuration has been found numerically by solving the dirac equation in the coulomb potential of the nucleus with the radius @xmath31 fm ( where @xmath32 is the atomic number ) . the nucleus has been considered spherical with the homogeneous positive charge distribution . in this case the electron potential energy in the units of the electron mass is given by @xmath33 here @xmath34 , where @xmath35 is the modulus of the electron radius vector @xmath36 , @xmath37 is the nuclear charge ( @xmath38 for th ) . the large ( @xmath39 ) and small ( @xmath40 ) radial components of the electron wave function @xmath41 are found from the system @xmath42 where @xmath43 . the electron wave function is normalized by the condition @xmath44 . in the following we work with the variable @xmath34 instead of @xmath45 , where @xmath46 is the bohr radius , commonly used in atomic physics because for calculations of the bohr - weisskopf effect we need a nuclear scale . however , when necessary we will return to atomic units and give the values of the electron wave functions in units of @xmath47 to compare with the calculations of other authors . the calculation of the bohr - weisskopf effect for the @xmath12 electron state in the @xmath13 three electron configuration has been performed by three different methods , fig . [ fig:2s_wavefunctions ] . of the @xmath12 state ( in a.u . ) calculated in various models ( see text for details ) . @xmath2th@xmath48 is the hygrogen - like ion model for the @xmath12 state ( i.e. the model without screening ) . @xmath2ra@xmath49 stands for the full screening of the nuclear charge + 2 by two electrons in the @xmath11 state . @xmath2th@xmath50 , full line : the potential from two electrons in the @xmath11 state is added to the nuclear potential . @xmath2th@xmath50 , dashed line : _ ab initio _ dft calculation @xcite ] at first , we have found the upper and lower boundaries for the @xmath12 electron wave function . for this purpose we have used the wave function of the @xmath12 state obtained in the field of the hydrogen - like ion . as the hydrogen - like ion we take ( i ) the @xmath2th@xmath3 ion with @xmath38 and ( ii ) the @xmath2ra@xmath4 ion . in the last case we have assumed that two electrons in the @xmath11 state perfectly screen the nuclear charge + 2 , and @xmath51 . in the second model we have used a more sophisticated approach by adding to the nuclear potential ( [ eq : potential ] ) the coulomb contribution from the electron density of two electrons in the @xmath11 state . the shortcoming of this calculation is that it does not take into account the interaction between electrons in the @xmath11 state and between electrons in the @xmath11 and @xmath12 states . finally , we have carried out _ ab initio _ numerical calculations inside and outside the nuclear region within the density functional method ( dft ) taking the full account of the electron self - consistent field by employing the atomic part of the code @xcite . the precise atomic dft calculations have been performed with two main variants for the exchange correlation potential and energy . the first functional belongs to the local density approximation ( lda ) @xcite , while the second to the generalized gradient approximation ( gga ) of perdew , burke , and ernzerhof ( pbe ) @xcite . both variants represent standard choices within the dft method . as follows from fig . [ fig:2s_wavefunctions ] the refined calculation of the large component @xmath52 of the @xmath12 state practically coincides with the calculation in the second model with the additional potential created by the two noninteracting @xmath11 electrons . moreover , for some estimations of the magnetic field and mhf interaction one can use the simple calculation in the hygrogen - like ion model for @xmath2th@xmath48 . the difference in the amplitude of the @xmath12 large component at nucleus , @xmath53 , for the @xmath54 configuration in @xmath2th@xmath3 and for the @xmath13 configuration in @xmath2th@xmath4 amounts to 2.5% . for many applications this difference is not essential . to evaluate the magnetic field one can use eq . ( [ eq : h ] ) with @xmath55 , where @xmath56 is the spherical harmonic with @xmath57 describing the angular part of the @xmath58states . ( notice that for @xmath58states @xmath59 . ) we have @xmath60 for the @xmath30 configuration in the @xmath2th@xmath3 ion and @xmath61 for the @xmath12 state in the @xmath13 configuration of the @xmath2th@xmath4 ion according to the _ ab initio _ calculations . now by means of eq . ( [ eq : h ] ) we obtain 112 mt for the magnetic field at the @xmath2th nucleus of the @xmath2th@xmath3 ion and 20 mt for the magnetic field of the @xmath2th@xmath4 ion . notice that in the atomic units @xmath62 , where @xmath63 , and @xmath64 . the influence of the finite nuclear size on the hyperfine splitting was first considered by bohr and weisskopf @xcite . later the effect of the distribution of nuclear magnetization on hyperfine structure in muonic atoms was studied by le bellac @xcite . according to their works , the energy of sublevels of a deformed nucleus is given by eq . ( [ eq : e ] ) , where @xmath65 is the energy of the interaction of the electron current @xmath66 ( @xmath67 , @xmath68 are the dirac matrices ) with the vector potential of the electromagnetic field @xmath69 generated by the magnetic moment of the nucleus . for a system of `` rotating deformed core ( with the collective rotating angular momentum @xmath70 ) + unpaired neutron ( with the spin @xmath71 ) '' , the vector - potential is determined by the relation @xcite @xmath72 \times { \mbox{\boldmath $ \nabla$}}_r\frac{1}{|{\bf{r}}-{\bf{r}}| } , \label{eq : a}\end{aligned}\ ] ] where @xmath73 is the distribution of the spin part of the nuclear moment and @xmath74 is the distribution of the core magnetization , @xmath75 is the spin @xmath39-factor , and @xmath76 is the core gyromagnetic ratio . the distributions @xmath73 and @xmath74 are normalized by the conditions @xmath77 , @xmath78 . as follows from eqs . ( [ eq : eint][eq : a ] ) , @xmath79 consists of two parts , @xmath80 . here @xmath81 is the energy of the electron interacting with an external unpaired neutron and @xmath82 is the energy of the electron interacting with the rotating charged nuclear core . these energies are calculated in accordance with formulas from @xcite . in our case the electron interacts with the nucleus in the head levels of rotational bands ( for such states we have @xmath83 , where @xmath84 is the component of @xmath26 along the symmetry axis of the nucleus ) , and two contributions are given by @xmath85 , \label{eq : eintneutron}\end{aligned}\ ] ] @xmath86 . \label{eq : eintcore}\end{aligned}\ ] ] here , @xmath87 is the wave function of the external neutron ( see below ) , @xmath88 is the intrinsic @xmath39 factor , @xmath89 , @xmath90 is the radius vector of the unpaired neutron , and @xmath91 is the normalized nuclear magnetic moment . in the present approach we consider the homogeneous positive charge distribution inside the nuclear sphere , which results in @xmath92 we conclude this section by noting that the first term in the square brackets of eqs . ( [ eq : eintneutron ] ) and ( [ eq : eintcore ] ) , @xmath93 , corresponds to the interaction of the electron with a point nuclear magnetic dipole . the model of the electron interacting with the point nuclear magnetic dipole gives much more precise value of the hyperfine interaction than the fermi contact interaction , eqs . ( [ eq : h ] ) and ( [ eq : eint_fermi ] ) . for calculations of the nuclear part in eqs . ( [ eq : eintneutron])([eq : eintcore ] ) we use the standard nuclear wave function @xcite @xmath94 where @xmath95 is the wigner @xmath96-function @xcite , @xmath97 stands for the three euler angles , @xmath87 is the wave function of the external neutron coupled to the core , and @xmath98 is the component of @xmath26 along the direction of magnetic field . the wave functions @xmath99 of the unpaired neutron is taken from the nilsson model . the structure of the @xmath2th ground state @xmath9 is @xmath100=5/2^+[633]$ ] . the structure of the isomeric state @xmath1(7.8 ev ) is @xmath101 $ ] @xcite . for each of these states , the wave function has the form @xmath102 where the quantum number @xmath103 , @xmath104 and @xmath105 are new variables . here we have introduced new frequencies @xmath106 and @xmath107 , where @xmath108 mev is the harmonic oscillator frequency , @xmath109 , and @xmath110 is the parameter of the nuclear deformation defined by @xmath111 . for the wave function components we then obtain : @xmath112 where @xmath113 is the generalized laguerre polynomial , @xmath114 is the hermite polynomial @xcite , @xmath115 are the normalization factors . in our numerical calculations we took into account the asymmetry of the nucleon wave functions in eq . ( [ eq : eintneutron ] ) , but neglected the small difference between @xmath116 and @xmath117 . the energies of the sublevels calculated according to eqs.([eq : e ] ) , ( [ eq : eintneutron])-([eq : eintcore ] ) are given in tables [ tab : hps_229th89 + ] [ tab : hps_229th87 + ] , third columns . we observe that for the @xmath2th@xmath118 ions there is a reduction of the mhf splitting in comparison with the model of point nucleus . the reduction is 3% for the @xmath9 ground state and approximately 6% for the @xmath1(7.8 ev ) isomeric state . the difference can be explained by the following : the magnetic field produced by the spin of the nucleon is sensitive to the non - sphericity of the wave functions @xmath99 . this leads to the appearance of the additional averaging over the angle @xmath119 in eq . ( [ eq : eintneutron ] ) @xcite . averaging over the angles reduces the spin contribution with respect to the orbital part . a small imbalance emerged in the system leads to some violation of the `` fine tuning '' between the spin and orbital parts of the magnetic moment . the relative imbalance is larger for the isomeric state because its magnetic moment smaller than the magnetic moment of the ground state . .magnetic hyperfine splitting in the @xmath2th@xmath3 ion . the energy of the sublevels is in ev . [ cols="^,^,^,^,^ " , ] [ tab : grad ] to demonstrate the increased probability of the transitions 3 , 4 and 5 , we compare their widths with the radiative width @xmath120 for the @xmath121 isomeric transition in the naked nucleus @xmath2th . in that case only the operator @xmath122 remains in eq . ( [ eq : grad ] ) . we express its matrix element in terms of the reduced probability of the nuclear transition : @xmath123 we then arrive at @xmath124 . ( the factor @xmath125 is accounted for by the differences in the definition of the transition operators in the atomic @xcite and nuclear @xcite physics . ) as a result we have @xmath126 ev , which corresponds to @xmath127 min . in conclusion , the calculation of the magnetic hypefine structure of the ground state doublet ( the ground @xmath9 and the low energy @xmath10 ev ) isomeric states ) in the highly ionized ions @xmath2th@xmath3 and @xmath2th@xmath4 have been performed . we have demonstrated that in comparison with the point nucleus model the bohr - weisskopf effect ( finite distribution of nuclear magnetization ) decreases the hyperfine splitting by 3% for the ground state and by 6% for the isomeric state . the energies of the sublevels have been calculated by taking into account the mixing of states with the same quantum number @xmath128 . as a result of mixing the energy difference between two @xmath5 states increases by 0.04 ev in @xmath2th@xmath3 and 0.001 ev in @xmath2th@xmath4 . the mixing of states ( with the coefficients @xmath129 and @xmath130 ) has been taken into account in the estimation of the probability of spontaneous transitions . we have found that even in the @xmath2th@xmath4 ion the mixing leads to a large increase of the probability of radiative transitions . the transitions therefore are caused mainly by a small admixter of other quantum states . it is worth noting that the bohr - weisskopf effect completely compensates the energy shift of the @xmath131 level in the @xmath2th@xmath132 ions , caused by the mixing . it also has profound influence on the energy positions of the states with @xmath133 and @xmath134 . therefore , the data on the hyperfine splittings can be used for precise determination of the magnetic moments of the nuclear @xmath9 and @xmath10 ev ) states . our findings can be useful for experiments with highly ionized @xmath2th ions in the storage ring of accelerator complex . one of the authors ( e.t . ) is grateful to prof . s. wycech , who has drawn our attention to the importance of the calculation of the mhf splitting in the @xmath2th@xmath4 ion for experimental studies in the accelerator storage ring .

the magnetic hyperfine ( mhf ) structure of the @xmath0(0.0 ev ) ground state and the low - lying @xmath1(7.8 ev ) isomeric state of the @xmath2th nucleus in highly charged ions th@xmath3 and th@xmath4 is calculated . the distribution of the nuclear magnetization ( the bohr - weisskopf effect ) is accounted for in the framework of the collective nuclear model with the wave functions of the nilsson model for the unpaired neutron . the deviations of the mhf structure for the ground and isomeric states from their values in the model of point - like nuclear magnetic dipole are calculated . the influence of the mixing of the states with the same quantum number @xmath5 on the energy of sublevels is studied . taking into account the mixing of states , the probabilities of the transitions between the components of mhf structure are found .

the development of high - order schemes has been receiving an increasing amount of attention from practitioners in the fields of fluid dynamics and , only more recently , magnetohydrodynamics ( mhd ) . this interest is driven by a variety of reasons , such as the possibility of obtaining highly accurate solutions with reduced computational effort as well as the need to narrow the gap between the smallest resolved features and the dissipative scales . although several successful strategies have been developed in the context of the euler equations of gasdynamics , only few of them have been extended to mhd . in the present context , we focus our attention on high - order finite difference schemes for the solution of the compressible mhd equations in multiple spatial dimensions , @xmath0 & = & 0\,,\\ \noalign{\medskip } { \displaystyle}{\frac{\partial { \mathbf{b}}}{\partial t } } - \nabla\times\left({\mathbf{v}}\times{\mathbf{b}}\right ) & = & 0\,,\\ \noalign{\medskip } { \displaystyle}{\frac{\partial e}{\partial t } } + \nabla\cdot\left [ \left(e + p + \frac{{\mathbf{b}}^2}{2}\right){\mathbf{v } } - \left({\mathbf{v}}\cdot{\mathbf{b}}\right){\mathbf{b}}\right ] & = & 0\ , , \end{array}\ ] ] where @xmath1 , @xmath2 , @xmath3 , @xmath4 and @xmath5 are the fluid density , velocity vector , magnetic induction , energy and gas pressure , respectively . the system of equations ( [ eq : mhd ] ) is complemented by the divergence - free constraint of the magnetic field , @xmath6 and by an equation of state relating energy and pressures . for the present work we assume an ideal gas law @xmath7 where @xmath8 is the ratio of specific heats . traditional second - order schemes have been largely employed for the solution of eq . ( [ eq : mhd ] ) using either finite volume ( fv , e.g. , @xcite ) or finite difference ( fd , e.g. , @xcite ) methods . at the second - order level , the two approaches are essentially equivalent and popular schemes have been built on godunov - type discretizations based on the total variation diminishing ( tvd , @xcite ) property making use of slope - limited reconstructions . in spite of the excellent results produced in proximity of discontinuous waves where sharp non - oscillatory transitions can be obtained , tvd schemes still suffer from excessive unwanted numerical dissipation in regions of smooth flow . this deficiency owes to the inherent behavior of tvd methods that reduces the order of accuracy to first - order near local extrema ( clipping ) and smear linearly degenerate fields ( such as contact waves ) much more than shocks . furthermore , discretization errors are mainly responsible for the loss of accuracy . efforts to relax the tvd condition and overcome these limitations have been spent over the last decades towards the development of highly accurate schemes that retain the robustness common to second - order godunov - type methods . the original piecewise parabolic method ( ppm ) method by @xcite , for example , provides fourth - order accurate interface values in smooth regions ( in 1d ) and has been extended to mhd by @xcite and , more recently by @xcite . ppm , however , still degenerates to first - order at smooth extrema and attempts to solve the problem have been recently presented in @xcite and @xcite . based on a different approach , weighted essentially non - oscillatory ( weno , @xcite ) schemes have improved on their eno predecessor ( originally proposed by harten et al . @xcite ) and are now considered a powerful and effective tool for solving hyperbolic partial differential equations . weno methods provide highly accurate solutions in regions of smooth flow and non - oscillatory transitions in presence of discontinuous waves by combining different interpolation stencils of order @xmath9 into a weighted average of order @xmath10 . the nonlinear weights are adjusted by the local smoothness of the solution so that essentially zero weights are given to non smooth stencils while optimal weights are prescribed in smooth regions . weno scheme have been formulated in the context of mhd using both fd @xcite and fv formulations , @xcite . third- and fifth - order weno schemes have been recently improved in terms of reduced dissipation , better resolution properties and faster convergence rates ( see @xcite and @xcite ) and will be considered here . an alternative strategy is followed by the monotonicity preserving ( mp ) family of schemes by suresh & huynh @xcite who proposed to carry the reconstruction step by first computing an accurate and stable interface value and then by imposing monotonicity- and accuracy - preserving constraints to limit the original value . mp schemes have been successfully merged with weno methods by @xcite and employed in the context of relativistic mhd by @xcite . finally , a reconstruction procedure that avoids the clipping phenomenon has been recently discussed by ada & torrilhon @xcite who devised a new class of nonlinear limiter functions based upon a non - polynomial reconstruction showing good shape - preserving properties . it is important to point out that , for spatial accuracy higher than two , multidimensional fv schemes become notoriously more elaborate than their fd counterparts , since point values can no longer be interchanged with volume averages . as a result , fv schemes generally require fully multidimensional reconstructions and the solution of several riemann problems at a zone face providing the necessary number of quadrature points required by the desired level of accuracy , see , for instance , @xcite . however , fv algorithms do have the adventage that they are better suited to non - uniform grids and adaptive mesh hierarchies . high - order fv schemes have been recently ameliorated in the work of @xcite using either ader - weno schemes or least - squares polynomial reconstruction . conversely , multidimensional fd schemes evolve the point values of the conserved quantities and considerably ease up the coding efforts by restricting the computations of flux derivatives to one dimensional stencils . in this perspective , we present a new class of fd numerical schemes adopting a point - wise , cell - centered formulation of all of the flow quantities , including magnetic fields . the proposed schemes have order of accuracy three and five and their performance is compared through extensive testing on two and three - dimensional problems . selected third - order accurate schemes are i ) an improved version of the classical third - order weno scheme of @xcite based on new weight functions designed to improve accuracy near critical points @xcite and ii ) the recently proposed non - polynomial reconstruction of @xcite . selected fifth - order schemes include i ) the weno - z scheme of @xcite and ii ) the monotonicity preserving scheme of @xcite based on a fifth - order accurate interface value ( mp5 henceforth ) . the solenoidal constraint of the magnetic field is controlled by extending the hyperbolic / parabolic divergence cleaning technique of dedner et al . @xcite to fd schemes . this avoids the computational cost associated with an elliptic cleaning step as in @xcite , and the scrupulous treatment of staggered fields demanded by constrained transport algorithms , e.g. @xcite . furthermore , mignone & tzeferacos @xcite have shown through extensive testing , for a class of second - order accurate schemes , that the glm approach is robust and can achieve accuracy comparable to the constrained transport . the resulting class of schemes is explicit and fully conservative in mass , momentum , magnetic induction and energy . besides the ease of implementation and efficiency issues , the benefits offered by a method where all of the primary flow variables are placed at the same spatial position ease the task to add more complex physics . the comparison between the different methods of solution is conveniently handled using the pluto code for computational astrophysics @xcite . the paper is structured as follows . in [ sec : eqns ] we describe the glm - mhd equations , while [ sec : numscheme ] shows the finite difference formulation and the selected reconstruction methods . in [ sec : numtest ] we test and compare the different scheme performance on problems involving the propagation of both continuous and discontinuous features . conclusions are drawn in [ sec : conclusions ] . we look at a conservative discretization of the mhd equations ( [ eq : mhd ] ) where all fluid variables retain a cell - centered collocation and enforce the divergence - free condition through the hyperbolic / parabolic divergence cleaning technique of dedner s @xcite . in this approach gauss s and faraday s laws of magnetism are modified by the introduction of a new scalar field function or generalized lagrangian multiplier ( glm henceforth ) @xmath11 . the resulting system of glm - mhd equations then reads @xmath12 with conservative state vector @xmath13 and fluxes @xmath14 defined by @xmath15 where @xmath16 labels the different components while @xmath17 is the delta kronecker symbol . equations ( [ eq : glm_mhd ] ) are hyperbolic and fully conservative with the only exception of the unphysical scalar field @xmath11 which satisfies a non - homogeneous equation with a source term . in the glm approach , divergence errors are propagated to the domain boundaries at finite speed @xmath18 and damped at a rate given by @xmath19 ( see [ sec : eqns ] ) . the eigenvalues of the mhd flux jacobians @xmath20 are all real and coincide with the ordinary mhd waves plus two additional modes @xmath21 , for a total of @xmath22 characteristic waves . restricting our attention to the @xmath23 direction , they are given by @xmath24 where @xmath25 are the fast magneto - sonic ( @xmath26 with the @xmath27 sign ) , slow magneto - sonic ( @xmath28 with the @xmath29 sign ) and alfvn velocities . the two additional modes @xmath21 are decoupled from the remaining ones and corresponds to linear waves carrying jumps in @xmath30 and @xmath11 . these waves are made to propagate at the maximum signal speed compatible with the time step , i.e. , @xmath31 where @xmath32 are the fast magneto - sonic speeds in the three directions and the maximum is taken throughout the domain . owing to the decoupling , one can treat the @xmath33 linear system given by the longitudinal component of the field @xmath34 and @xmath11 separately from the other ordinary @xmath35-wave mhd equations . as we shall see , this greatly simplifies the solution process and allows to use the standard characteristic decomposition of the mhd equations . following @xcite , we divide the solution process into an homogeneous step , where the glm - mhd ( [ eq : glm_mhd ] ) are solved with @xmath36 , and a source step , where integration is done analytically : @xmath37 where @xmath38 is the minimum grid size . extensive numerical testing has shown that divergence errors are minimized when the parameter @xmath39 lies in the range @xmath40 $ ] depending on the particular problem , although in presence of smooth flows this choice seems to be less sensitive to the numerical value of @xmath39 . we consider a conservative finite difference discretization of ( [ eq : glm_mhd ] ) where point - values rather than volume averages are evolved in time . a uniform cartesian mesh is employed with cell sizes @xmath41 centered at @xmath42 , where @xmath43 label the computational zones in the three directions . for clarity of exposition , we disregard the integer subscripts when redundant but always keep the half increment index notation when referring to a cell boundary , e.g. , @xmath44 . integration in time resorts to a semi - discrete formulation where , given a high - order numerical approximation @xmath45 to the derivatives appearing on the right hand side of eq . ( [ eq : glm_mhd ] ) , one is faced with the solution of the following initial value problem @xmath46 with initial condition given by the point - wise values of @xmath47 . we choose the popular third - order runge - kutta scheme @xcite to advance the solution in time , for which one has @xmath48 the choice of the time step @xmath49 is restricted by the courant - friedrichs - levy ( cfl ) condition : @xmath50 where @xmath51 is the cfl number . since the time step is proportional to the mesh size , the overall accuracy of the scheme is restricted to third - order because of the time - stepping introduced in eq . ( [ eq : rk3 ] ) . our task is now to provide a stable and accurate non - oscillatory numerical approximation to @xmath45 . to this purpose , we begin by focusing our attention to the @xmath52 direction and set , for ease of notations , @xmath53 . we then let point values of the flux @xmath54 correspond to the volume averages of another function , say @xmath55 , and define @xmath56 \,,\quad\textrm{where}\quad { \mathbf{h}}(x ) = \int_{-\infty}^x \hat{{\mathbf{f}}}(\xi)d\xi\,.\ ] ] in this formalism , point values of the flux @xmath54 are identified as cell averages of @xmath57 and @xmath58 may be regarded as the primitive function of @xmath55 . straightforward differentiation of eq . ( [ eq : flux_primitive ] ) yields the conservative approximation @xmath59 stated in this form , the problem consists of finding a high - order approximation to the interface values of @xmath60 knowing the undivided differences of the primitive function @xmath58 , a procedure entirely analogous to that used in the context of finite volume methods such as ppm @xcite . thus one can set @xmath61}\right)\,,\ ] ] where @xmath62 is a highly accurate reconstruction scheme providing a stable interface flux value from point - wise values and the index @xmath63 $ ] spans through the interpolation stencil . the procedure can be repeated in an entirely similar way also for the @xmath64 and @xmath65 flux contributions and allows to write the @xmath66 operator in ( [ eq : ivp ] ) as @xmath67 this yields the fully unsplit approach considered in this paper . alternatively , one could use a directionally split formalism to obtain the solution through a sequence of one dimensional problems separately corresponding to each term in equation ( [ eq : l ] ) . in order to ensure robustness and to avoid the appearance of spurious oscillations , the reconstruction step is best carried with the help of local characteristic fields and by separately evaluating contributions coming from right- and left - going waves . to this end we first compute , using the simple arithmetic average @xmath68 , left and right eigenvectors @xmath69 and @xmath70 of the jacobian matrix @xmath71 , for each characteristic field @xmath72 . we then obtain a projection of the positive and negative part of the flux using a simple rusanov lax - friedrichs flux splitting : @xmath73 } & = & \frac{1}{2}{\mathbf{l}}^{\kappa}_{i+{\frac{1}{2}}}\cdot \left({\mathbf{f}}_{[s ] } + \alpha^{\kappa}{\mathbf{u}}_{[s]}\right ) \ , , \\ \noalign{\medskip } v^{\kappa,-}_{i+{\frac{1}{2}},[s ] } & = & \frac{1}{2}{\mathbf{l}}^{\kappa}_{i+{\frac{1}{2}}}\cdot \left({\mathbf{f}}_{[s ' ] } - \alpha^{\kappa}{\mathbf{u}}_{[s']}\right ) \ , , \end{array}\right.\ ] ] where @xmath74}$ ] and @xmath75}$ ] are the point - wise values of the flux and conservative variables . for a typical one - point upwind - biased approximation of order @xmath76 , one has @xmath63 = i - r,\dots , i+r$ ] while @xmath77 = 2i-[s]+1 $ ] mirrors left - going characteristic fields with respect to the interface @xmath78 . the coefficient @xmath79 represents the maximum absolute value of the @xmath80-th characteristic speed throughout the domain . the global lax - friedrichs flux splitting thus introduced is particularly diffusive and other forms of splitting are of course possible , e.g. @xcite . however , we have found that the level of extra numerical dissipation tend to become less important for higher - order scheme . the interface flux is then written as a local expansion in the right - eigenvector space : @xmath81 where the coefficients @xmath82}\right)\,.\ ] ] are the reconstructed interface values of the local characteristic fields and @xmath62 can be any one of the procedures described in [ sec : recon ] . the procedure illustrated so far is valid for an arbitrary system of hyperbolic conservation laws , provided @xmath83 and @xmath84 satisfy @xmath85 i.e. , they are left and right eigenvectors of the flux jacobian , respectively . however , following @xcite , we wish to exploit the full @xmath86 characteristic decomposition of the usual mhd equations rather than resorting to a full @xmath87 diagonalization procedure . to this purpose , we take advantage of the fact that the longitudinal component of the field @xmath30 and the lagrange multiplier @xmath11 satisfy @xmath88 and are thus decoupled from the remaining seven mhd equations . eq . ( [ eq:2x2 ] ) defines a constant coefficient linear hyperbolic system with left and right eigenvectors given , respectively , by the rows and columns of @xmath89 associated with the eigenvalues @xmath90 and @xmath91 . the @xmath33 linear system ( [ eq:2x2 ] ) can be preliminary solved to find the values of @xmath30 and @xmath11 at a given interface . indeed , by applying the projection ( [ eq : char_vars ] ) to the linear system ( [ eq:2x2 ] ) using eq . ( [ eq:2x2_evect ] ) , one obtains that the only non trivial characteristic fields are @xmath92 } = \frac{1}{2}\left(\psi_{[s ' ] } - c_hb_{x,[s']}\right)\,,\quad v^{9,+}_{i+{\frac{1}{2}},[s ] } = \frac{1}{2}\left(\psi_{[s ] } + c_hb_{x,[s]}\right)\,.\ ] ] since the eigenvectors are constant in space , the local projection at @xmath78 are completely unnecessary and the computations in eq . ( [ eq : k19 ] ) can be carried out very efficiently throughout the grid . once ( [ eq : k19 ] ) have been reconstructed using eq . ( [ eq : interp ] ) one defines @xmath93 and proceed by solving the ordinary @xmath86 mhd equations using @xmath94 defined by ( [ eq : bx_intrfc ] ) as a constant parameter . we have shown in [ sec : numscheme ] that flux derivatives may be written in conservative form by applying any one - dimensional finite volume reconstruction to the point values of the flux @xmath54 . among the variety of different strategies we investigate both third- and fifth - order accurate interpolation schemes making use of three- and five - point stencil , respectively : * an improved version of the classical third - order weno scheme of @xcite based on new weight functions designed to improve accuracy near critical points ( weno+3 , [ sec : weno3 ] ) ; * the recently proposed limo3@xmath95third - order reconstruction of @xcite , [ sec : limo3 ] . * the improved weno5 scheme of @xcite also known as weno - z ( [ sec : wenoz ] ) ; * the monotonicity preserving scheme of @xcite based on a fifth - order interface value ( mp5 , [ sec : mp5 ] ) . our choice is motivated by the sake of comparing well - known and recently presented state of the art algorithms that rely on heavy usage of conditional statements ( limo3@xmath95and mp5 ) or completely avoid them ( weno+3 and weno - z ) . the proposed algorithms are applied to the left ( - ) and right ( + ) propagating characteristic fields defined by eq . ( [ eq : char_vars ] ) to provide an accurate interface value , formally represented by eq . ( [ eq : interp ] ) . thus , in our formulation , the total number of reconstruction is @xmath96 : two for the linear characteristic fields defined by eq . ( [ eq : k19 ] ) and @xmath97 for the left- and right - going wave families defined by eq . ( [ eq : char_vars ] ) with @xmath98 . in the following we will drop the @xmath78 index for the sake of exposition and shorten either one of ( [ eq : char_vars ] ) with @xmath99}$ ] . undivided difference will be frequently used and denoted with @xmath100 occasionally , we will also make use of the @xmath101 and @xmath102 functions defined , respectively as @xmath103 in the classical third - order weno scheme of @xcite , the interface value is reconstructed using the information available on a three - point local stencil @xmath104 . more specifically , a third - order accurate value is provided by a linear convex combination of second - order fluxes : @xmath105}\right ) = \omega_0\frac { f_i + f_{i+1}}{2 } + \omega_1\frac{-f_{i-1 } + 3f_{i}}{2}\,.\ ] ] the weights @xmath106 for @xmath107 are defined by @xmath108 where @xmath109 are optimal weights and the smoothness indicators @xmath110 give a measure of the regularity of the corresponding polynomial approximation . the scheme has been recently improved in the work by yamaleev & carpenter , @xcite , where the introduction of an additional nonlinear artificial dissipation term was shown to make the scheme stable in the l2-energy norm for both continuous and discontinuous solutions . yamaleev & carpenter also derived new weight functions providing faster convergence and improved accuracy at critical points . the improved weights are still defined by eq . ( [ eq : w3:omega ] ) with @xmath111 replaced by @xmath112 to avoid loss of accuracy at critical points , it was shown in @xcite that @xmath113 has to satisfy @xmath114 . here adopt the conventional third - order scheme defined by eq . ( [ eq : w3])-([eq : w3:omega ] ) but with @xmath111 replaced by eq . ( [ eq : w3:newomega ] ) and simply set @xmath115 . this improves the accuracy over the original @xmath116 order scheme of @xcite in regions where the solution is smooth and provides essentially non - oscillatory solutions near strong discontinuities and unresolved features . the improved third - order weno scheme just described will be referred to as weno+3 . recently , ada and torrilhon @xcite have proposed a new and efficient third - order limiter function in the context of finite volume schemes . similarly to the @xmath116-order weno scheme described in [ sec : weno3 ] , the new limiter employs a local three - point stencil to achieve piecewise - parabolic reconstruction for smooth data and preserves the accuracy at local extrema , thus avoiding the well known clipping of classical second - order tvd limiters . interface values are reconstructed using a simple piecewise - linear max / min function acting as a logical switch depending on the left and right slope : @xmath117}\right ) = f_i + \frac{\delta_{i+{\frac{1}{2}}}}{2 } \left[p_3(\theta ) + \chi\left(\hat{\phi}(\theta)-p_3(\theta)\right)\right ] \,,\ ] ] where @xmath118 is the slope ratio , @xmath119 is the building block giving polynomial quadratic reconstruction and @xmath120 is the third - order limiter @xmath121 & \quad\mathrm{if}\quad \theta \ge 0 \ , , \\ \noalign{\medskip } { \displaystyle}\max\left[0 , \min\left(p_3(\theta),-\frac{\theta}{2}\right)\right ] & \quad\mathrm{if}\quad \theta < 0 \ , . \end{array}\right.\ ] ] the function @xmath122 in eq . ( [ eq : limo3 ] ) smoothly switches between limited and unlimited reconstructions based on a local indicator function @xmath123 properly introduced to avoid loss of accuracy at smooth extrema with one vanishing lateral derivative : @xmath124 \,,\qquad \eta = \frac{\delta_{i-{\frac{1}{2}}}^2 + \delta_{i+{\frac{1}{2}}}^2}{(r\delta x)^2}\,,\ ] ] where @xmath125 . the function @xmath123 measures the curvature of non - monotone data inside a computational zone and the free - parameter @xmath126 is used to discriminate between smooth extrema and shallow gradients . larger values of @xmath9 noticeably improve the reconstruction properties at the cost of introducing more local variation , see @xcite . in the tests presented here we use @xmath127 . borges et al . @xcite presented an improved version of the classical fifth - order weighted essentially non - oscillatory ( weno ) fd scheme of @xcite . the new scheme , denoted with weno - z , has been shown to be less dissipative and provide better resolution at critical points at a very modest additional computational cost . we will employ such scheme here and , for the sake of completeness , report only the essential steps for its implementation ( for a thorough discussion see the paper by @xcite ) . following the general idea of weno reconstruction , one considers the convex combination of different third - order accurate interface values built on the three possible sub - stencils of @xmath128 : @xmath129}\right ) = \omega_0\frac { 2f_{i-2 } - 7f_{i-1 } + 11f_{i}}{6 } + \omega_1\frac{- f_{i-1 } + 5f_{i } + 2f_{i+1}}{6 } + \omega_2\frac { 2f_{i } + 5f_{i+1 } - f_{i+2}}{6 } \,.\ ] ] the weights @xmath106 for @xmath130 are defined by @xmath131 where @xmath132 are the optimal weights giving a fifth - order accurate approximation , @xmath133 is a small number preventing division by zero and the smoothness indicators @xmath110 give a measure of the regularity of the corresponding polynomial approximation : @xmath134 while maintaining the essentially non - oscillatory behavior , the new formulation makes use of higher - order information about the regularity of the solution thus providing enhanced order of convergence at critical points as well as reduced dissipation at discontinuities . the monotonicity preserving ( mp ) schemes of suresh & huynh @xcite achieve high - order interface reconstruction by first providing an accurate polynomial interpolation and then by limiting the resulting value so as to preserve monotonicity near discontinuities and accuracy in smooth regions . the mp algorithm is better sought on stencils with five or more points in order to distinguish between local extrema and a genuine @xmath135 discontinuities . here we employ the fifth - order accurate scheme based on the ( unlimited ) interface value given by @xmath136 based on the five point values @xmath137 . together with ( [ eq : mp_hi ] ) , we also define the monotonicity - preserving bound @xmath138 resulting from the median between @xmath139 , @xmath140 and the left - sided extrapolated upper limit @xmath141 . the parameter @xmath142 controls the maximum steepness of the left sided slope and preserves monotonicity during a single runge - kutta stage ( eq . [ eq : rk3 ] ) provided the cfl number satisfies @xmath143 . in practice , setting @xmath144 still allows larger values of @xmath51 to be used . the interface value given by eq . ( [ eq : mp_hi ] ) is not altered when the data is sufficiently smooth or monotone that @xmath145 lies inside the interval defined by @xmath146 $ ] . otherwise limiting takes place by bringing the original value back into a new interval @xmath147 $ ] specifically designed to preserve accuracy near smooth extrema and provide monotone profile close to discontinuous data . the final reconstruction can be written as @xmath129}\right ) = \left\{\begin{array}{ll } f_{i+{\frac{1}{2 } } } & \quad\mathrm{if}\quad ( f_{i+{\frac{1}{2}}}-f_i)(f_{i+{\frac{1}{2 } } } - f^{\rm mp})<0 \ , , \\ \noalign{\medskip } { \mathrm{median}}\left(f^{\min } , f_{i+{\frac{1}{2}}},f^{\max}\right ) & \quad\mathrm{otherwise } \ , , \end{array}\right.\ ] ] where @xmath148\ , , \\ \noalign{\medskip } f^{\max } & = & { \displaystyle}\min\left[\max\left(f_i , f_{i+1 } , f^{\rm md}\right),\ , \max\left(f_i , f^{\rm ul } , f^{\rm lc}\right)\right]\ , . \end{array}\ ] ] the bounds given by eq . ( [ eq : mp_fminmax ] ) provide accuracy - preserving constraints by allowing the original interface value @xmath145 to lie in a somewhat larger interval than @xmath149 $ ] or @xmath150 $ ] . this is accomplished by considering the intersection of the two extended intervals @xmath151 $ ] and @xmath152 $ ] that leave enough room to accommodate smooth extrema based on a measure of the local curvature defined by @xmath153 where @xmath154 . using eq . ( [ eq : mp_m4 ] ) , one defines the median @xmath155 and the large curvature @xmath156 values as @xmath157 respectively . the curvature measure provided by ( [ eq : mp_m4 ] ) is somewhat heuristic and chosen to reduce the amount of room for local extrema to develop . the reconstruction illustrated preserves monotonicity and does not degenerate to first - order in proximity of smooth extrema . in this section we present a series of test problems aimed at the verification of the fd methods previously described . the selected algorithms have been implemented in the pluto code for astrophysical gas - dynamics @xcite in order to ease inter - scheme comparisons through a flexible common computational framework . unless otherwise stated , the specific heat ratio will be set to @xmath158 and the courant number @xmath51 will be taken equal to @xmath159 , @xmath160 or @xmath161 for one , two and three dimensional computations , respectively . errors for a generic flow quantity @xmath162 are computed using the @xmath163 discrete norm defined by @xmath164 where the summation extends to all grid zones , @xmath165 and @xmath166 are the number of grid points in the three directions and @xmath167 is a reference solution . the divergence of magnetic field is quantified using eq . ( [ eq : l1 ] ) with @xmath168 computed as @xmath169 where the interface values are obtained through eq . ( [ eq : bx_intrfc ] ) . we start by considering a planar , circularly polarized alfvn wave propagating along the @xmath170 direction . as the wave propagates , density and pressure stay constant whereas transverse vector components trace circles without changing their magnitude . denoting with @xmath171 and @xmath172 the angular frequency and wavenumber , respectively , one has @xmath173 where @xmath174 , @xmath175 is the corresponding phase velocity ( @xmath176 is the alfvn speed ) and @xmath177 is the wave amplitude . the plus or minus sign corresponds to right or left propagating waves , respectively . here we consider a standing wave for which one has @xmath178 and further set @xmath179 , @xmath180 . the one - dimensional solution given by ( [ eq : alfv_1d ] ) is first rotated by an angle @xmath181 around the @xmath64 axis and subsequently by an angle @xmath182 around the @xmath65 axis , as in @xcite . the resulting transformation leaves scalar quantities invariant and produces vector rotations @xmath183 , where @xmath184 is either velocity or magnetic field and @xmath185 are the rotation matrix and its inverse . note that the rotation can be equivalently specified by prescribing the orientation of the wave vector @xmath186 in a three - dimensional cartesian frame through the angles @xmath182 and @xmath187 such that @xmath188 such that @xmath189 . with these choices , @xmath190 in ( [ eq : alfv_1d ] ) becomes @xmath191 where @xmath192 . periodicity is guaranteed by setting , without loss of generality , @xmath193 and by choosing the computational domain @xmath194 $ ] , @xmath195 $ ] and @xmath196 $ ] . with these definitions the wave returns into the original position after one period @xmath197 different configurations can be specified in terms of the four parameters @xmath198 and @xmath199 ( background pressure ) . one and two dimensional propagation are recovered by setting @xmath200 and @xmath201 , respectively . @ lr rrrr & & & + method & @xmath202 & @xmath203 & @xmath204 & @xmath203 & @xmath204 + weno+3 & 16 & 3.45e-03 & - & 2.54e-02 & - + & 32 & 4.39e-04 & 2.97 & 3.68e-03 & 2.79 + & 64 & 5.52e-05 & 2.99 & 4.47e-04 & 3.04 + & 128 & 6.91e-06 & 3.00 & 5.51e-05 & 3.02 + & 256 & 8.64e-07 & 3.00 & 6.85e-06 & 3.01 + limo3@xmath95 & 16 & 3.36e-03 & - & 2.82e-02 & - + & 32 & 4.36e-04 & 2.95 & 3.76e-03 & 2.91 + & 64 & 5.53e-05 & 2.98 & 4.34e-04 & 3.11 + & 128 & 6.91e-06 & 3.00 & 5.46e-05 & 2.99 + & 256 & 8.65e-07 & 3.00 & 6.84e-06 & 3.00 + weno - z & 16 & 7.50e-04 & - & 4.10e-03 & - + & 32 & 2.40e-05 & 4.96 & 1.32e-04 & 4.96 + & 64 & 7.55e-07 & 4.99 & 3.89e-06 & 5.09 + & 128 & 2.36e-08 & 5.00 & 1.20e-07 & 5.02 + & 256 & 7.37e-10 & 5.00 & 3.74e-09 & 5.00 + mp5 & 16 & 7.38e-04 & - & 3.41e-03 & - + & 32 & 2.40e-05 & 4.94 & 1.19e-04 & 4.84 + & 64 & 7.55e-07 & 4.99 & 3.81e-06 & 4.97 + & 128 & 2.36e-08 & 5.00 & 1.20e-07 & 4.99 + & 256 & 7.37e-10 & 5.00 & 3.74e-09 & 5.00 + as a first test , we consider one - dimensional propagating waves on the segment @xmath205 $ ] using @xmath206 grid points with @xmath207 . we set the background pressure to be @xmath208 and the wave amplitude @xmath209 . the glm correction is not necessary and has turned off for one dimensional propagation . in order to investigate the convergence of solution , the integration time step is adjusted to @xmath210 where @xmath211 is the nominal time increment at the minimum resolution @xmath212 , whereas @xmath213 is the spatial accuracy of the scheme . errors ( in @xmath163 norm ) for the four selected schemes are plotted after one wave period @xmath214 in the left panel of fig [ fig : alfv ] and arranged , together with the corresponding order of convergence , in the third and fourth columns of table [ tab : alfv ] . all schemes meet the expected order of accuracy ( i.e. 3 for limo3@xmath95and weno+3 , 5 for weno - z and mp5 ) with no significant differences . it is remarkable that , at the resolution of @xmath215 zones , the fifth - order schemes achieve essentially the same accuracy as the third - order schemes that make use of four times ( i.e. @xmath216 ) as many points . a three dimensional configuration is obtained by rotating the one - dimensional setup described in [ sec : alfv1d ] by the angles @xmath217 so that @xmath218 in eq . ( [ eq : rot_mat ] ) . the background pressure is @xmath208 and the wave has amplitude @xmath209 . the size of the computational box turns out to be @xmath205 $ ] , @xmath219 $ ] , @xmath220 $ ] and the number of grid points is set by @xmath221 , where @xmath202 changes as in [ sec : alfv1d ] . integration lasts for one wave period , i.e. , @xmath222 and the time step is determined by the same condition given by eq . ( [ eq : dt_adj ] ) . thus , apart from the different normalization , our setup is identical to that used in @xcite . errors are plotted at different resolutions in the right panel of fig [ fig : alfv ] and sorted in table [ tab : alfv ] for all schemes . on average , errors are @xmath223 larger than their one - dimensional counterparts but the overall behavior meets the expected order of accuracy with mp5 and limo3@xmath95performing slightly better than weno - z and weno+3 , respectively . as for the 1d case , roughly @xmath224 of the resolution is required by a fifth - order scheme to match the accuracy of a third - order one . following @xcite , we construct in fig [ fig : scatter ] a scatter plot of the magnetic field component parallel to the @xmath64 axis of the original one dimensional frame . this is achieved by plotting , for every point in the computational domain , the @xmath64 component of @xmath225 as a function of the normal ( @xmath170 ) coordinate of @xmath226 , where @xmath227 is the rotation matrix introduced in ( [ eq : rot_mat ] ) . the ability of the scheme to retain the planar symmetry during the computation is confirmed by the lack of scatter in the plots . the profiles at different resolutions verify the general trend established in table [ tab : alfv ] and deviations from the exact solution appear to be imperceptible for @xmath228 for the third - order schemes and already at @xmath229 for the fifth - order schemes . overally , the results obtained with third- and fifth - order accurate schemes outperform traditional tvd schemes , such as the ct - ppm algorithm of @xcite yielding at most second - order accurate solutions . the cpu costs associated with weno+3 , limo3@xmath95 , weno - z and mp5 show , for this test problem , a relative scaling @xmath230 , respectively . as already stated , circularly polarized alfvn waves are an exact nonlinear solution of the mhd equations and measuring their decay provides a direct indication of the intrinsic numerical viscosity and resistivity possessed by the underlying algorithm , see @xcite . this study is relevant , for example , in the field of mhd turbulence modeling where one should carefully control the amount of directionally - biased dissipation introduced by waves propagating inclined to the mesh . the error introduced during an oblique propagation is usually minimized at @xmath231 since contributions coming from different directions have comparable magnitude . on the contrary , waves propagating at smaller inclination angles make the problem more challenging . our setup builds on @xcite although we adopt a slightly different , more severe , configuration . using the notations introduced in [ sec : alfv ] , we set @xmath232 , @xmath233 , @xmath234 and prescribe the background pressure to be @xmath235 . the corresponding ratio of the plasma pressure to the ( unperturbed ) magnetic pressure is then given by @xmath236 , where @xmath180 is the wave propagation speed . the choice of the inclination angle determines the computational domain @xmath205 $ ] , @xmath237 $ ] as well as the wave period @xmath238 from eq . ( [ eq : alfv_period ] ) . the final integration time @xmath239 is chosen by having the wave cross the domain @xmath240 times . this configuration results in a more arduous test than @xcite where the wave period was @xmath241 longer and the integration was stopped after @xmath242 wave transits . fig [ fig : decay ] shows , at the resolution of @xmath243 mesh points , the maximum values of the vertical @xmath65 components of velocity ( left panel ) and magnetic field ( right panel ) as functions of time . by the end of the simulation , third - order schemes ( dashed lines ) show some degree of dissipation with the wave amplitude being reduced to @xmath244 per cent of its initial value . on the contrary , schemes of order five ( solid lines in the figure ) preserve the original shape more accurately and the amplitude retains @xmath245 per cent of its nominal value . these results are compared , for illustrative purposes , to a @xmath246 order tvd scheme using the monotonized central difference limiter ( dotted lines ) , showing that the initial peak values have scaled down to @xmath247 per cent , thus showing a considerably larger level of numerical dissipation . these results are in agreement with previous investigations @xcite and strongly supports the idea that problems involving complex wave interactions may benefit from using higher - order schemes such as the ones presented here . shock tube problems are commonly used to test the ability of the scheme in describing both continuous and discontinuous flow features . in the following we consider two and three dimensional rotated configurations of standard one dimensional tubes . the default value for the parameter @xmath39 controlling monopole damping ( see eq . [ eq : source_exp ] ) is @xmath159 . following @xcite , we consider a rotated version of the brio - wu test problem @xcite with left and right states are given by @xmath248 where @xmath249 is the vector of primitive variables . the subscript `` 1 '' gives the direction perpendicular to the initial surface of discontinuity whereas `` 2 '' corresponds to the transverse direction . here @xmath250 is used and the evolution is interrupted at time @xmath251 , before the fast waves reach the borders . in order to address the ability to preserve the initial planar symmetry we rotate the initial condition by the angle @xmath252 in a two dimensional plane with @xmath253 $ ] and @xmath254 $ ] using @xmath255 grid points , with @xmath256 . vectors follow the same transformation given by eq . ( [ eq : rot_mat ] ) with @xmath257 . this is known to minimize errors of the longitudinal component of the magnetic field ( see for example the discussions in @xcite ) . boundary conditions respect the translational invariance specified by the rotation : for each flow quantity we prescribe @xmath258 where @xmath259 , with the plus ( minus ) sign for the leftmost and upper ( rightmost and lower ) boundary . computations are stopped before the fast rarefaction waves reach the boundaries , at @xmath260 . fig [ fig : sod2d ] shows the primitive variable profiles for all schemes against a one - dimensional reference solution obtained on a base grid of @xmath261 zones with @xmath262 levels of refinement . errors in @xmath163 norm , computed with respect to the same reference solution , are sorted in table [ table : sod ] for density and the normal component of magnetic field . the out - coming wave pattern is comprised , from left to right , of a fast rarefaction , a compound wave ( an intermediate shock followed by a slow rarefaction ) , a contact discontinuity , a slow shock and a fast rarefaction wave . we see that all discontinuities are captured correctly and the overall behavior matches the reference solution very well . the normal component of magnetic field is best described with mp5 and does not show erroneous jumps . indeed , the profiles are essentially constant with small amplitude oscillations showing a relative peak @xmath263 . divergence errors , typically @xmath264 , remain bounded with resolution and tend to saturate when the damping parameter @xmath265 for both 2 and 3d calculations , see fig [ fig : sod_alpha ] . in this sense , our results favourably compare to those of @xcite and @xcite . fifth - order methods exhibit less dissipation across jumps , with fewer points in each discontinuous layer . still , the accuracy gained from third to fifth - order accurate schemes ( see table [ table : sod ] ) is only a factor @xmath266 since interpolation across discontinuities usually degenerates to lower - order to suppress spurious oscillations . @ lr rrrrr & & & & + method & @xmath267 & @xmath268 & @xmath269 & @xmath267 & @xmath268 & @xmath269 + weno+3 & 4.11e-03 & 8.53e-05 & 7.19e-03 & 1.82e-03 & 4.41e-05 & 7.12e-03 + limo3@xmath95 & 3.61e-03 & 8.74e-05 & 1.08e-02 & 1.63e-03 & 4.07e-05 & 9.41e-03 + weno - z & 2.72e-03 & 7.90e-05 & 1.48e-02 & 1.29e-03 & 5.41e-05 & 1.59e-02 + mp5 & 2.31e-03 & 6.24e-05 & 7.60e-03 & 1.07e-03 & 2.22e-05 & 1.37e-02 + the second riemann problem was introduced by @xcite and later considered by @xcite and by @xcite in 3d . the primitive variables are initialized as @xmath270 where @xmath271 . a reference solution at @xmath272 is obtained on the domain @xmath273 $ ] using @xmath274 grid points and @xmath262 levels of refinement . our setup draws on the three dimensional version of @xcite and @xcite where the initial condition ( [ eq : ic_3dst ] ) is rotated using eq . ( [ eq : rot_mat ] ) by the angles @xmath182 and @xmath181 such that @xmath275 and @xmath276 ( corresponding to @xmath277 ) . with this choice the planar symmetry is respected by an integer shift of cells . the computational domain consists of @xmath278 zones and spans @xmath279 $ ] in the @xmath170 direction while @xmath280 $ ] . computations stop at @xmath281 ( note the misprint in @xcite ) . fig [ fig : sod3d_a ] and [ fig : sod3d_b ] show primitive variable profiles obtained with third- and fifth - order schemes , respectively . the wave pattern consists of a contact discontinuity that separates two fast shocks , two slow shocks and a pair of rotational discontinuities . table [ table : sod ] confirms again that the gain from high - order methods is not particularly significant when the flow is discontinuous . our results favorably compare with those of other investigators and no prominent over / under - shoots are observed . moreover , the amount of oscillations in the normal component of the magnetic field is comparable to ( or smaller than ) those found in @xcite and divergence errors behave in a very similar way to the 2d case ( see also the right panel in fig [ fig : sod_alpha ] ) . the computational costs relative to that of weno+3 ( @xmath282 ) are found , for this problem , to be @xmath283 for limo3@xmath95 , weno - z and mp5 , respectively . the following problem has been introduced in @xcite and lately considered by @xcite . the initial condition , satisfying the time - independent mhd equations , consists of a magnetized vortex structure in force equilibrium that propagates along the main diagonal of the computational box ( a square in 2d and a cube in 3d ) . here we set @xmath284 . following dumbser et al . @xcite , we perform computations on the cartesian box @xmath285 ^ 2 $ ] with an initial flow described by @xmath179 , @xmath286 , @xmath287 and @xmath288 . the constants @xmath80 and @xmath289 are chosen to be equal to @xmath290 while @xmath291 . the simulations are evolved for 10 time units with periodic boundary conditions , i.e. a single passage of the vortex through the domain . the parameter @xmath292 is chosen equal to @xmath293 for third - order schemes , effectively reproducing the configuration shown in @xcite . for weno - z and mp5 , on the other hand , we choose @xmath294 in order to reduce the unwanted effects produced by the small jump in the magnetic field at the periodic boundaries , as argued in @xcite . in order to compare our results to the findings of the latter study , we report , in table [ table : l1_vortex ] , errors for @xmath30 measured both in @xmath163 and @xmath295 norms and the corresponding convergence rates . all schemes quickly converge to the asymptotic order of accuracy . remarkably , errors obtained with the third - order schemes are identical and somewhat better than those of @xcite . at the resolution of @xmath296 , fifth - order schemes yield errors @xmath223 times smaller than third - order ones at @xmath297 . a comparison between third- and fifth - order schemes from fig [ fig : vortex ] reveals that divergence errors rapidly decrease with resolution following a similar pattern . this eloquently advocates towards the use of higher - order schemes . @ cc cccccccccc & & & + method & @xmath202 & @xmath298 & @xmath204 & @xmath299 & @xmath300 & @xmath298 & @xmath204 & @xmath299 & @xmath300 + weno+3 & 32 & 2.49e-03 & - & 1.94e-04 & - & 7.81e-04 & - & 1.74e-05 & - + & 64 & 4.13e-04 & 2.6 & 1.73e-05 & 3.5 & 1.29e-04 & 2.6 & 1.12e-06 & 4.0 + & 128 & 5.72e-05 & 2.9 & 1.16e-06 & 3.9 & 1.82e-05 & 2.8 & 5.38e-08 & 4.4 + & 256 & 7.69e-06 & 2.9 & 7.24e-08 & 4.0 & - & - & - & - + limo3@xmath95 & 32 & 2.49e-03 & - & 1.94e-04 & - & 7.81e-04 & - & 1.74e-05 & - + & 64 & 4.13e-04 & 2.6 & 1.73e-05 & 3.5 & 1.29e-04 & 2.6 & 1.12e-06 & 4.0 + & 128 & 5.72e-05 & 2.9 & 1.16e-06 & 3.9 & 1.82e-05 & 2.8 & 5.38e-08 & 4.4 + & 256 & 7.69e-06 & 2.9 & 7.24e-08 & 4.0 & - & - & - & - + weno - z & 32 & 8.17e-04 & - & 1.02e-04 & - & 1.63e-04 & - & 7.39e-06 & - + & 64 & 5.10e-05 & 4.0 & 2.89e-06 & 5.1 & 1.07e-05 & 3.9 & 1.50e-07 & 5.6 + & 128 & 1.83e-06 & 4.8 & 5.23e-08 & 5.8 & 3.78e-07 & 4.8 & 1.87e-09 & 6.3 + & 256 & 5.94e-08 & 4.9 & 8.28e-10 & 6.0 & - & - & - & - + mp5 & 32 & 9.57e-04 & - & 1.04e-04 & - & 1.96e-04 & - & 7.34e-06 & - + & 64 & 5.16e-05 & 4.2 & 3.02e-06 & 5.1 & 1.07e-05 & 4.2 & 1.53e-07 & 5.6 + & 128 & 1.75e-06 & 4.9 & 5.15e-08 & 5.9 & 3.66e-07 & 4.9 & 1.85e-09 & 6.4 + & 256 & 5.69e-08 & 4.9 & 8.04e-10 & 6.0 & - & - & - & - + we propose a novel three dimensional extension of the vortex problem , consisting of similar initial conditions as the 2d case , albeit the radius @xmath9 now refers to the spherical one , @xmath301 . the perturbation of pressure is now given by @xmath302\,{\rm e}^{2\,q\,(1-r^2)}\,,\ ] ] while we prescribe also a vertical velocity @xmath303 . the computational domain is the cube @xmath285 ^ 3 $ ] with periodic boundary conditions . the evolution stops after 10 time units . the last four columns of table [ table : l1_vortex ] report the @xmath163 and @xmath295 norm errors of @xmath30 showing an excellent agreement with the analytical solution . notice that the errors measured in @xmath295 norm are systematically smaller than @xmath163 errors and a comparison between similar configurations using different norms ( as reported in @xcite ) may be deceitful . keeping that in mind and given the somewhat diverse configurations , one can see that our results ( in @xmath295 norm ) are competitive with those of @xcite at least at a qualitative level . divergence errors , shown in fig [ fig : vortex ] , quickly decrease as the mesh thickens and fall below @xmath304 at the resolution of @xmath305 for the fifth - order schemes . the computational cost is in accordance with previous tests , giving a ratio of @xmath306 for weno+3 , limo3@xmath95 , weno - z and mp5 , respectively . we now consider the advection of a magnetic field loop . for sufficiently large plasma @xmath187 , specifying a thermal pressure dominance , the loop is transported as a passive scalar . the preservation of the initial circular shape tests the scheme s dissipative properties and the correct discretization balance of multidimensional terms @xcite . following @xcite , the computational box is defined by @xmath253 $ ] and @xmath307 $ ] discretized on @xmath308 grid cells ( @xmath309 ) . density and pressure are initially constant and equal to @xmath310 . the velocity of the flow is given by @xmath311 with @xmath312 , @xmath313 and @xmath314 . the magnetic field is defined through its magnetic vector potential as @xmath315 where @xmath316 , @xmath317 , @xmath318 , @xmath319 , @xmath320 and @xmath321 . the modification to the vector potential in the @xmath322 region ( with respect to similar setups presented by other investigators ) is done to remove the singularity in the loop s center that can cause spurious oscillations and erroneous evaluations of the magnetic energy . the simulations are allowed to evolve until @xmath323 ensuring the crossing of the loop twice through the periodic boundaries . in fig . [ fig : fl2d ] the magnetic energy density is displayed for the limo3@xmath95 , weno+3 , weno - z and mp5 schemes , along with iso - contours of the @xmath65 component of the magnetic vector potential . the initial circular shape is preserved well by all schemes . the third - order schemes are substantially more diffusive , as can be seen on the borders of the loop . this is confirmed by the time evolution of the magnetic energy density ( normalized to its initial value ) , plotted in the left panel of fig.[fig : fl2d_energy ] . the power law behaviour is similar for the schemes of the same order , with the mp5 method being the least diffusive . no pronounced difference is found between the limo3@xmath95and weno+3 schemes , for this particular problem . the divergence of magnetic field measured in @xmath163 norm is shown in the left panel of fig [ fig : fl_alpha ] , as a function of @xmath324 $ ] . for the fifth - order schemes errors are minimized when @xmath325 whereas limo3@xmath95and weno+3 present smaller errors for @xmath326 . the three dimensional version of this problem is particularly challenging as the correct evolution depends on how accurately the @xmath327 condition is preserved and how the multidimensional mhd terms are balanced out . the computational domain @xmath328 , @xmath329 , @xmath330 is resolved onto @xmath331 zones . as for the two - dimensional case the vector potential @xmath332 is used to initialize the magnetic field , which is then rotated using the coordinate transformation given by eq . ( [ eq : rot_mat ] ) with @xmath333 and @xmath334 . even though the loop is rotated only around one axis , the velocity profile @xmath335 makes the test intrinsically three - dimensional . once again , pressure and density are taken uniform and equal to unity while boundary conditions are periodic in all directions . the preservation of the loop s shape can be seen in fig . [ fig : fl3d ] . all schemes preserve the shape , with limo3@xmath95and weno+3 being equally more diffusive ( notice the thickness of the dark area at the loop s borders , as well as the brighter ring just inside the loop ) . as for the 2d case , one can see that mp5 is the least diffusive in preserving the magnetic energy ( right panel of fig . [ fig : fl2d_energy ] ) , while the dissipation rates for limo3@xmath95and weno+3 practically coincide . moreover , the three - dimensional @xmath163 norm error of @xmath168 ( right panel of fig [ fig : fl_alpha ] ) exhibits a behaviour similar to the two dimensional case . as before , the relative cpu scaling between weno+3 , limo3@xmath95 , weno - z and mp5 for this test problem is @xmath336 . the orszag - tang vortex system describes a doubly periodic fluid configuration leading to two - dimensional supersonic mhd turbulence . the domain @xmath40 ^ 2 $ ] is initially filled with constant density and pressure respectively equal to @xmath337 and @xmath338 , while velocity and magnetic field are initialized to @xmath339 and @xmath340 , respectively . although an analytical solution is not known , its simple and reproducible set of initial conditions has made it a widespread benchmark for inter - scheme comparison , see for example @xcite . density contour plots , as in @xcite are shown in the top and bottom rows of fig . [ fig : ot ] at @xmath341 and @xmath342 , respectively , using a resolution of @xmath297 points . the dynamics is regulated by multiple shock interactions leading to the formation of small scale vortices and density fluctuations . our results at @xmath341 are in good agreement with previous investigations , e.g. @xcite , with weno+3 and limo3@xmath95 showing increased numerical dissipation when compared to weno - z and mp5 . this is further confirmed in fig [ fig : ot_slice ] where horizontal cuts at @xmath343 in the pressure distribution are plotted against a reference solution obtained with the second - order ct - ctu scheme of @xcite on a finer mesh ( @xmath344 ) , see also @xcite . the most noticeable difference occurs at @xmath342 , when the fifth - order schemes ( in particular , mp5 ) reveal the formation of a central magnetic island featuring a high density spot also recognizable in the results of @xcite and in @xcite for the isothermal case . this structure is absent in the third - order schemes and may be induced by the decreased effective resistivity across the central current sheet , as discussed in @xcite . divergence errors , shown in fig [ fig : ot_divb ] at @xmath341 , are comparable with those given by other investigators ( e.g. @xcite ) and reach their maximum magnitude in presence of discontinuous features . the computational cost of limo3@xmath95 , weno - z and mp5 relative to that of weno+3 ( @xmath282 ) are found to be @xmath345 , in analogy with the previous results . as a final example , we propose the nonlinear evolution of the kelvin - helmholtz instability in two dimensions . the base flow consists of a single shear layer with an initially uniform magnetic field lying in the @xmath346 plane at an angle @xmath347 with the direction of propagation : @xmath348 \,,\quad { \mathbf{b } } = c_a\sqrt{\rho}\big[\cos\theta,\ , 0,\ , \sin\theta\big]\,,\ ] ] where @xmath349 is the mach number , @xmath350 is the steepness of the shear , @xmath351 is the alfvn speed . density and pressure are initially constant and equal to @xmath179 and @xmath352 . a single - mode perturbation @xmath353 $ ] with @xmath354 , @xmath355 is super - imposed as in @xcite . computations are carried out in a cartesian box @xmath40\times[-1,1]$ ] for @xmath356 time units on a @xmath357 mesh , where @xmath358 . the evolutionary stages are shown in fig [ fig : khsnap ] , where we display color maps of the ratio @xmath359 at the largest resolution @xmath360 for weno+3 , limo3@xmath95 , weno - z and mp5 . for @xmath361 the perturbation follows a linear growth phase during which magnetic field lines wound up through the formation of a typical cat s eye vortex structure , @xcite , see the top row in fig [ fig : khsnap ] . during this phase , magnetic field lines become distorted all the way down to the smaller diffusive scales and the resulting field amplification becomes larger for higher magnetic reynolds numbers . as such , we observe in the top row of fig [ fig : khgrowth ] that the magnetic energy grows faster not only as the resolution is increased from @xmath215 to @xmath362 mesh points ( green , red , black ) , but also when switching from a third - order to a fifth order scheme ( solid vs. dotted lines ) . in particular , one can see that half of the grid resolution is needed by mp5 to match the results obtained with weno+3 . a somewhat lesser gain can be inferred by comparing weno - z and limo3@xmath95 . similarly , the growth rate ( computed as @xmath363 see bottom panel in fig . [ fig : khgrowth ] ) , is closely related to the poloidal field amplification and evolves faster for smaller numerical resistivity and thus for finer grids and/or less dissipative schemes . field amplification is eventually prevented when @xmath364 by tearing mode instabilities leading to reconnection events capable of expelling magnetic flux from the vortex ( second row in fig . [ fig : khsnap ] ) , @xcite . throughout the saturation phase ( third and fourth row in fig [ fig : khsnap ] ) the mixing layer enlarges and the field lines thicken into filamentary structures . during this phase one can clearly recognize that small scale structures are best spotted with the fifth - order methods while they appear to be more diffused with weno+3 and limo3@xmath95 . the cpu costs relative to that of weno+3 ( @xmath282 ) follow the ratios @xmath365 for limo3@xmath95 , weno - z and mp5 , respectively , and confirm the same trend already established in previous tests . we have presented a class of high - order finite difference schemes for the solution of the compressible ideal mhd equations in multiple spatial dimensions . the numerical framework adopts a point - wise , cell centered representation of the primary flow variables and has been conveniently cast in conservation form by providing highly accurate interface values through a one - dimensional finite volume reconstruction approach . the divergence - free condition of magnetic field is monitored by introducing a scalar generalized lagrange multiplier , as in @xcite , offering propagation as well as damping of divergence errors in a mixed hyperbolic / parabolic way . this greatly simplifies the task of obtaining highly accurate solutions since the reconstruction process can be carried out on one - dimensional stencils using the information available at cell centers . in this respect , our formulation completely avoids expensive elliptic cleaning steps , does not require genuinely multidimensional interpolation and eludes the complexities required by staggered mesh algorithms . selected numerical schemes based on third- as well as fifth - order accurate constraints have been presented and compared . * the recently improved version of the third - order weno scheme ( weno+3 , @xcite ) and the limo3@xmath95reconstruction based on new limiter functions ( introduced in @xcite ) perform equally well exhibiting third - order accuracy in smooth problems and non - oscillatory transitions at discontinuities . * the new fifth - order weno scheme ( weno - z , see @xcite ) and the monotonicity preserving algorithm ( mp5 ) of @xcite yield high - quality results on all of the selected tests and report orders of accuracy close to @xmath262 for multidimensional smooth problems . both weno - z and mp5 perform with a greatly reduced amount of numerical dissipation and provide highly accurate solution with much fewer grid points when compared to third - order accurate schemes . still , we have found mp5 to give slightly better results weno - z in terms of reduced computational cost , improved accuracy and sharper transitions at discontinuous fronts . * fifth - order schemes are found to be @xmath366 ( for weno - z ) and @xmath367 ( for mp5 ) per cent slower than third - order ones , depending on the particular choice . this favorably advocates towards the use of higher order schemes rather than lower order ones , since the same level of accuracy can be attained at a much lower resolution still giving a tremendous gain in computing time . for three - dimensional problems , for example , the gain can be almost two orders of magnitude in cpu cost . * the results obtained with the present finite difference formulation are competitive ( in terms of accuracy and description of discontinuities ) with recently developed fv schemes ( e.g. , @xcite ) and noticeably improve over traditional @xmath246 order godunov - type schemes in terms of reduced numerical dissipation . the benefits offered by a high - order method such as the ones presented here are particularly relevant in the context of mhd applications involving both smooth and discontinuous flows . * acknowledgements . * extensive numerical testing of the finite difference schemes presented in this paper was made possible by the computational facilities available thanks to the inaf - cineca agreement . the @xmath87 matrix of the conservative mhd equations in one dimension introduced can be decomposed , given the eigenvalues ( see eq . [ eq : eigenvalues ] ) , to the corresponding left and right eigenvectors . following partially the notation of @xcite , we define @xmath368 where @xmath369 denotes the speed of sound . with this notation , the right eigenvectors in matrix form will be given by @xmath370 where @xmath371 , @xmath372 , @xmath373 and @xmath374 . l. del zanna , o. zanotti , n. bucciantini , p. londrillo echo : a eulerian conservative high - order scheme for general relativistic magnetohydrodynamics and magnetodynamics , astronomy & astrophysics 473 ( 2007 ) 11 m. dumbser , d.s . balsara , e.f . toro , c .- d . munz , a unified framework for the construction of one - step finite volume and discontinuous galerkin schemes on structured meshes . j. comput . ( 2008 ) 8209 - 8253 . s. fromang , p. hennebelle , r. teyssier , a high order godunov scheme with constrained transport and adaptive mesh refinement for astrophysical magnetohydrodynamics . astronomy & astrophysics 457 ( 2006 ) 371 . shu , 1997 essentially non - oscillatory and weighted essentially non - oscillatory schemes for hyperbolic conservation laws . technical report . umi order number : tr-97 - 65 . , institute for computer applications in science and engineering ( icase ) . norm errors computed for the one - dimensional alfvn wave propagation ( left panel ) and the rotated three - dimensional version ( right panel ) . the cross , triangle , plus sign and square symbols refer to computations carried out with weno+3 , limo3@xmath95 , weno - z and mp5 , respectively , at the resolution @xmath382 and @xmath362 points using a cfl number of @xmath159 ( in 1d ) and @xmath161 ( in 3d ) . the dotted lines gives the ideal convergence slope , that is , @xmath383 and @xmath384 , respectively . , title="fig:",scaledwidth=48.5% ] norm errors computed for the one - dimensional alfvn wave propagation ( left panel ) and the rotated three - dimensional version ( right panel ) . the cross , triangle , plus sign and square symbols refer to computations carried out with weno+3 , limo3@xmath95 , weno - z and mp5 , respectively , at the resolution @xmath382 and @xmath362 points using a cfl number of @xmath159 ( in 1d ) and @xmath161 ( in 3d ) . the dotted lines gives the ideal convergence slope , that is , @xmath383 and @xmath384 , respectively . , title="fig:",scaledwidth=48.5% ] component of magnetic field in the original one - dimensional frame at @xmath385 , after 5 revolutions . each panel plots every point of the three - dimensional array @xmath386 as a function of the longitudinal coordinate @xmath387 along the direction of wave propagation . the lack of scatter demonstrates that the algorithm retains the expected planar symmetry . the solid line gives the reference solution at @xmath388 while dotted , dashed and dot - dashed lines corresponds to computations carried with @xmath389 points , respectively . the cfl number was set to @xmath390 . ] time units , corresponding to @xmath391 wave periods . in the left panel , we plot the maximum value of the vertical component of velocity as a function of time for the weno - z ( solid line ) and weno+3 ( dashed line ) schemes . for comparison , the dotted line gives the result obtained by a second - order tvd scheme . the panel on the right shows the analogous behavior of the vertical component of magnetic field @xmath392 for limo3@xmath95and mp5 . for all cases , the resolution was set to @xmath243 and the courant number is @xmath160 . ] , along the rotated direction @xmath393 . from left to right : density , transverse velocity , longitudinal and transverse magnetic field components are displayed . the mesh resolution is @xmath394 and the courant number is @xmath160 . symbols correspond to the 2d computations whereas the solid lines gives the reference solution . ] obtained with the third - order schemes . density , pressure , velocity and magnetic field components parallel and transverse to the direction of propagation are plotted as functions of the longitudinal component @xmath395 . the mesh resolution is @xmath278 and the courant number is @xmath161 . ] for the shock tube problems in 2d ( left , @xmath396 ) and 3d ( right , @xmath397 ) . symbols in black color are used to distinguish between different schemes at the nominal resolutions ( @xmath394 in 2d and @xmath278 in 3d ) , see the legend . computations carried at twice the resolution ( @xmath398 in 2d and @xmath399 in 3d ) are shown using symbols in red color . ] computed with the third - order ( left ) and fifth - order ( right ) schemes at the resolution of @xmath400 points with courant number @xmath401 . magnetic field lines are overplotted using 9 contour levels equally spaced between @xmath402 and @xmath403.,scaledwidth=90.0% ] grid points . the magnetic energy is better conserved for the mp5 method . limo3@xmath95and weno+3 show no pronounced difference for this particular problem.,title="fig:",scaledwidth=45.0% ] grid points . the magnetic energy is better conserved for the mp5 method . limo3@xmath95and weno+3 show no pronounced difference for this particular problem.,title="fig:",scaledwidth=45.0% ] computed on @xmath404 grid zones with courant number @xmath161 . from left to right : limo3@xmath95 , weno+3 , weno - z , mp5 . all schemes preserve the circularity of the loop , with the fifth - order schemes displaying sharper borders . ] norm error of the divergence of magnetic field as functions of the resolution ( @xmath202 ) for the 2d ( left panel ) and 3d ( right panel ) vortex problems at @xmath405 . different symbols corresponds to the selected reconstruction algorithms.,title="fig:",scaledwidth=45.0% ] norm error of the divergence of magnetic field as functions of the resolution ( @xmath202 ) for the 2d ( left panel ) and 3d ( right panel ) vortex problems at @xmath405 . different symbols corresponds to the selected reconstruction algorithms.,title="fig:",scaledwidth=45.0% ] ( top ) and @xmath342 ( bottom ) for the selected schemes using @xmath297 grid points . thirty equally spaced levels ranging from @xmath406 to @xmath407 for the top panel and from @xmath408 to @xmath409 for the bottom panel are shown . ] showing gas pressure in the orszag - tang system at @xmath341 at the resolution of @xmath297 . mp5 and weno+3 are shown in top panel ( squares and plus signs ) , weno - z and limo3@xmath95 in the bottom . the solid line gives a reference solution obtained with second - order constrained transport algorithm on @xmath344 zones . ] ( first panel from top ) , @xmath410 ( second panel ) , @xmath411 ( third panel ) and @xmath356 ( bottom panel ) . the images show the ratio of the poloidal field strength and the toroidal component , @xmath412 . left to right columns corresponds to computations obtained with weno+3 , limo3@xmath95 , weno - z and mp5 , respectively , at the resolution of @xmath360 . note how the colorbar maximum value changes at different instant to reflect the corresponding magnetic field strength.,scaledwidth=80.0% ] ) as functions of time . here @xmath413 accounts for the `` poloidal '' contribution only . solid and dotted lines corresponds to integrations carried with weno - z and limo3@xmath95(left panels ) , mp5 and weno+3 ( right panels ) . the different colors , green , red and black indicate different numerical resolution , i.e. , @xmath215 , @xmath414 and @xmath362 , respectively . , scaledwidth=80.0% ]

we present and compare third- as well as fifth - order accurate finite difference schemes for the numerical solution of the compressible ideal mhd equations in multiple spatial dimensions . the selected methods lean on four different reconstruction techniques based on recently improved versions of the weighted essentially non - oscillatory ( weno ) schemes , monotonicity preserving ( mp ) schemes as well as slope - limited polynomial reconstruction . the proposed numerical methods are highly accurate in smooth regions of the flow , avoid loss of accuracy in proximity of smooth extrema and provide sharp non - oscillatory transitions at discontinuities . we suggest a numerical formulation based on a cell - centered approach where all of the primary flow variables are discretized at the zone center . the divergence - free condition is enforced by augmenting the mhd equations with a generalized lagrange multiplier yielding a mixed hyperbolic / parabolic correction , as in dedner et al . ( j. comput . phys . 175 ( 2002 ) 645 - 673 ) . the resulting family of schemes is robust , cost - effective and straightforward to implement . compared to previous existing approaches , it completely avoids the cpu intensive workload associated with an elliptic divergence cleaning step and the additional complexities required by staggered mesh algorithms . extensive numerical testing demonstrate the robustness and reliability of the proposed framework for computations involving both smooth and discontinuous features . magnetohydrodynamics , compressible flow , higher - order methods , weno schemes , monotonicity preserving , cell - centered methods

anomalous raman scattering , characterised by surprisingly strong features in the multi - order scattering , and with intensities comparable to the one - phonon scattering , seems to be a general property of rare - earth ( @xmath3 ) manganites @xmath3mno@xmath0 @xcite . this phenomenon is directly related to a problem of the existence of a new type of elementary excitation an orbital wave excitation or a new particle called `` orbiton '' in the correlated electron systems with broken symmetry @xcite . usually , an orbital excitation is associated with an energy gap , induced in the two - fold degenerate electronic @xmath4 levels of mn@xmath2 ions by electron superexchange ( se ) interaction @xcite and/or jahn - teller ( jt ) electron - lattice interaction @xcite . unfortunately , an uncertainty in parameters of superexchange interaction , particularly in the mott hubbard value @xmath5 from one side , and in the jt energy @xmath6 from the other side , is still a challenge for theoreticians and it is not yet clear where the orbitons should be looked for in measurements . in a limit of weak jt coupling , the orbital excitations in lamno@xmath0 are predicted to appear around 1600 @xmath1 ( 0.2 ev ) , as a result of the superexchange interaction @xcite , which indicates on the feature , observed in the second - order raman scattering experiment in the 9001400 @xmath1 ( 0.110.17 ev ) range @xcite . if the contributions from se and jt effects are considered on equal footing , the elementary excitations of the system , according to the theory predictions , are mixed modes with both phonon and orbital character , and the phonon - orbital excitations appear as franck condon sidebands at energy intervals of the jahn teller vibrational energy @xcite . alternatively , in a limit of strong jt coupling , and strong electronic correlations at @xmath7 , the orbitons in lamno@xmath0 could be self - trapped excitons with energy @xmath6 ; then the anomalous raman scattering could be interpreted as a result of multiphonon scattering , induced by the resonant optical excitation of 2 ev across the large jt gap , and activated by the franck - condon process @xcite . however , in our comprehensive experimental ( ellipsometry ) and theoretical studies of lamno@xmath0 , we argue that the optical excitation at 2 ev is an intersite @xmath8 transition , governed by superexchage interaction , and evaluate the effective mott - hubbard parameter @[email protected] ev @xcite . on the other side , it is argued by iliev _ _ that the oxygen isotope substitution effect in the rare - earth manganites @xmath3mno@xmath0 provides strong evidence that the multi - order raman spectra are of pure phonon character , rather than of orbiton or mixed orbiton - phonon character , and that the multi - order scattering has predominantly the oxygen phonon density - of - states ( pdos ) origin @xcite . these interpretations of the anomalous raman scattering in rare - earth manganites @xmath3mno@xmath0 are ambiguous and are a subject of intense debate , questioning the roles of the jt electron - lattice and/or se interactions . moreover , even the existence of orbital excitations in these correlated systems with broken symmetry is still unproven experimentally or theoretically . as it was shown in the earlier study by sarfatt and stoneham @xcite , and in exact agreement with the prediction of the goldstone theorem @xcite , octahedral complexes of cu@xmath10 ( and mn@xmath2 ) ions represent striking illustration of the system with broken symmetry , where an excitation branch should exist , which frequency tends to zero in the limit of infinite wavelengths . the nature of the goldstone mode in octahedral complexes of cu@xmath10 ( and mn@xmath2 ) ions , in the way noted by sarfatt - stoneham @xcite , is associated with the rotation by angle @xmath11 going round the rim at the minimum of a double - valued `` mexican hat '' energy surface @xcite . this rotation is characteristic of the pure `` mexican hat '' limit , and corresponds to oscillations in the configuration of octahedral complexes , determined by the partial occupation of the electronic @xmath4 orbitals . this should result in acoustic orbital wave propagation from relative motions of different ions , where close ions have similar phases @xmath11 . when the electron - lattice coupling can be considered infinite , additional terms in the lagrangian , such as anharmonicity , could destroy the broken symmetry and the the zero - point motion round the rim at the minimum of the `` mexican hat '' . in such a case , the ground state is often determined by several energetically equivalent wells , and in the static case the system is confined to one of them . however , if the coupling is finite , fluctuations between the energetically equivalent wells of the distorted geometry lead to the tunneling states @xcite . let us consider the model materials , lamno@xmath0 and kcuf@xmath0 , for a cooperative jt effect , which also exhibit antiferromagnetic ordering ( at @xmath12 of 140 k and 39 k , respectively ) due to heisenberg - type exchange interaction @xcite . in a recent optical study of kcuf@xmath0 with orbital ordering temperature of @xmath13 k , a new temperature scale @xmath14 , characterised by the emergence of sharp absorption features due to the on - site @xmath8 transitions , followed by a sideband of magnon excitations , correlating with changes in the orbital ordering @xcite prior to the magnetic ordering , has been established @xcite . the sideband excitations were ascribed to the zone - boundary magnons ( or their combinations ) , which became optically - active via exchange - induced dipole mechanism . it was suggested that a dynamic distortion of the environment of the cu@xmath10 ions becomes static below @xmath15 k , which leads to a symmetry change , affects the orbital ordering , and paves the way for the antiferromagnetic ordering . simultaneously , the phonon modes , involving the displacement of f@xmath16 ions , soften with decreasing temperature @xcite . similarly , lamno@xmath0 , with orbital ordering temperature of @xmath17 k , exhibits changes in the orbital ordering - superlattice reflection , as measured by x - ray photoemission scattering in the vicinity of @xmath12 @xcite , and softening of the raman - active phonon modes @xcite . therefore , we suggest that the interplay of superexchange and jt electron - lattice interaction in the heisenberg antiferromagnets lamno@xmath0 and kcuf@xmath0 is accompanied by the observed anomalous sideband excitations ( zone - boundary phonons or magnons ) , which become optically - active due to the distortion of the octahedral environment of the cu@xmath10 and mn@xmath2 ions . in such a case , a significant change of the orbital - ordering - superlattice structure could be indicative of the dynamic - to - static jt transition in these compounds . in this paper , the anomalous multi - order raman scattering is investigated for a detwinned lamno@xmath0 crystal up to a fourth order . here we present the results of a comprehensive study of the temperature and polarisation dependences of the first- and higher - order raman scattering . based on the analysis of the obtained data , we suggest that the anomalous raman scattering is due to sidebands on the low - energy mode at about 25 @xmath1 . this behaviour is anisotropic , as within our experimental accuracy we have no indication on the presence of the low - energy mode in the @xmath18-polarised raman spectra . we argue that this low - energy mode originates from the electron tunneling between the potential energy minima arising near the jt mn@xmath2 ion due to the lattice anharmonicity , and the multi - order scattering is activated by this low - energy electronic motion . indeed , the frequency of the mode at about 25 @xmath1 is consistent with the tunneling frequencies in the dynamic limit of the jt effect in , for example , a @xmath19d system of 3 @xmath20 mgo : cu@xmath10 and 3 @xmath21 caf@xmath22 : sc@xmath10 @xcite . in addition , there is an experimental evidence of the low - energy mode observed at around 25 @xmath1 in a far - infrared experiment in doped rare - earth manganites @xcite . the sidebands are dominated by the phonon density - of - states ( pdos ) of oxygen vibrations @xcite . surprisingly , as we have discovered during our study , aside from the oxygen - phonon density - of - states feature , there is an additional component to the multi - order scattering , which exhibits a different behaviour . we consider that this behaviour may arise from an admixture of the electronic component in the case of a weak vibronic interaction , when the barriers between the minima are less than the characteristic vibrational frequency , and a special coupling between low - frequency electronic motions and vibrational modes takes place @xcite . we suggest that the superexchange interaction may be crucial in driving the system of @xmath4 electrons to the regime of the dynamic jt effect , with affordable barriers for the tunneling between the potential energy minima . single crystals of lamno@xmath0 were grown using the crucible - free floating zone method in a mirror furnace , equipped with an arc lamp @xcite . as - grown lamno@xmath0 crystals are single phased and , below the orbital ordering temperature @xmath23 k , exhibit heavily twinned domain patterns in the orthorhombic _ pbnm _ structure . the particular pattern and the size of the domains depend on local temperature gradients and mechanical stresses , experienced during the growth stage . we were able to remove the twins from an essential part of the sample volume following the procedure , described in detail in our previous study @xcite . as a result , the percentage of detwinning detected at some areas of the crystal surface was as high as 95 % and over the entire surface it was at least 80 % . the orthorhombic [ 010 ] direction was identified as perpendicular to the crystal surface by single - crystal x - ray diffraction . the sample was further characterised by magnetometry , using a superconducting quantum interference device . we determined the antiferromagnetic transition temperature @xmath12 at 139.6 k , which is characteristic of a nearly oxygen - stoichiometric lamno@xmath0 crystal . the sample surface was polished to optical grade for further optical measurements . raman spectra were obtained using a raman - microscope spectrometer labram hr ( horiba jobin yvon ) , equipped with a grating monochromator and a liquid - nitrogen cooled ccd detector . the spectrometer has high spectral resolution ( 0.3 @xmath1/pixel at 633 nm ) , large spectral range of raman shift from 100 to 4000 @xmath1 and unique edge filter technology . hene laser source operating at 632.8 nm wavelength ( 1.96ev ) , with appropriate filters , was used for excitation under different irradiation power . the sample was mounted on a cold finger of the micro - cryostat , cooled with liquid nitrogen . we employed the near - normal back - scattering geometry with an adjustable confocal pinhole ; the propagation direction of the incident and scattered light was parallel to the principal [ 010 ] orthorhombic axis of the detwinned lamno@xmath0 crystal . the distinctive principle polarisations were recorded in the described here raman experiment , using generic linear polarisation of the laser radiation while rotating the sample in the @xmath24 plane . crystal symmetry determines the number of vibrational raman - active normal modes . a factor - group analysis of the orthorhombic crystal structure of lamno@xmath0 ( space group @xmath25 , @xmath26 ) with 4 f.u./unit cell yields a total number of 24 ( 7@xmath27 ) raman - active phonon modes . the raman scattering tensor determines whether the normal modes actually appear , and could be observed under irradiation with a polarised light at a given scattering geometry . on the oriented sample surface , the @xmath28 symmetry phonons appear in the parallel @xmath29 , @xmath30 , and @xmath31 polarisations of the incident and scattered light , whereas the @xmath32 , @xmath33 , and @xmath34 phonons appear in the crossed ( @xmath35 ) , ( @xmath36 ) , and ( @xmath37 ) polarisations , respectively . figure 1(a , c ) shows the low - temperature ( 80 k ) and room - temperature ( 300 k ) micro - raman spectra measured on the detwinned lamno@xmath0 crystal for the two selected polarisations of the incident hene laser irradiation , along the main @xmath18 crystallographic direction and along the @xmath38 direction , rotated by 45@xmath39 . with the incident light , polarised along the @xmath38 direction , we observed @xmath40 symmetry modes , whereas with the incident light , polarised along the @xmath18 axis , only @xmath28 symmetry modes became pronounced . at low temperature ( 80 k ) , our raman scattering measurements allowed us to identify six modes of @xmath28 symmetry at 148 , 210 , 267 , 295 , 452 , and 495 @xmath1 and four modes of @xmath32 symmetry at 197 , 313 , 436 , and 606 @xmath1 . two strong high - frequency modes @xmath28 ( 495 @xmath1 ) and @xmath32 ( 606 @xmath1 ) correspond to the in - plane vibrations , associated with jt in - phase anti - symmetric and symmetric stretching of the corner - shared oxygen octahedra in the lamno@xmath0 structure , respectively @xcite . superimposed low - temperature raman spectra , measured for three selected polarisations in the @xmath24 plane , which were normalised to the strong @xmath28 ( 495 @xmath1 ) mode , are shown in fig . the highest - frequency @xmath32 ( 606 @xmath1 ) mode is noticeably less pronounced than the @xmath28 mode in the @xmath41 polarisation , whereas it is almost completely suppressed in the @xmath18 polarisation . our raman phonon spectra are similar to those of an earlier raman study of the detwinned lamno@xmath0 single crystal by saitoh _ _ @xcite . in order to determine frequencies , widths , and integrated intensities of the phonon bands , we fitted our polarised raman spectra , measured at temperatures 80 k @xmath42 k , with a set of lorentzians . figure 2(a , b ) shows temperature dependences of the frequencies and full widths at half maximum ( fwhm ) of the two strong high - frequency modes , @xmath28 and @xmath32 . in agreement with the earlier observation by granado _ _ , the @xmath32 mode shows softening below the nel temperature , which was interpreted as a consequence of magnetostriction effects @xcite . the temperature dependence was less pronounced for the frequency of the @xmath28 mode , which reveals weak polarisation dependence . at the same time , the widths of these two modes showed no distinct anomaly near the nel temperature , increasing linearly with rising temperature in the studied temperature range . the temperature coefficient of the fwhm of the anti - symmetric jt @xmath28 mode ( averaged over the measured polarisations as shown in fig . 2(b ) ) is about 0.07 @xmath9 0.01 @xmath1/k , whereas for the symmetric jt @xmath32 mode it is approximately half that , about 0.04 @xmath9 0.01 @xmath1/k . figure 2(c ) shows temperature and polarisation dependences of the scaled integrated intensities of the @xmath28 and @xmath32 modes . remarkably , our raman study on the detwinned single crystal allowed us to detect the pronounced opposite trends in the temperature behaviour of the intensities of the @xmath28 mode , measured with the laser light polarised along the @xmath38 and @xmath18 directions ( however , we noticed different behaviour in the @xmath41 polarisation ) . moreover , the intensities of the @xmath28 and @xmath32 modes show a clear kink at the nel temperature at around 140 k. as it was established in the earlier study by krger _ @xcite , the raman cross - section of the one - phonon @xmath28 and @xmath32 modes shows resonant behaviour under a hene ( 1.96 ev ) light irradiation , which corresponds to a maximum of the optical gap excitation in lamno@xmath0 at around 2 ev @xcite . we note that the observed anisotropy and temperature dependences of the scaled raman intensities , measured with the incident laser light polarised along the @xmath38 and @xmath18 directions of the detwinned lamno@xmath0 crystal , followed the same trend as the anisotropic optical spectral weight of the 2 ev optical band , influenced by the spin - spin correlations between the mn@xmath2 spins via the superexchange interaction @xcite . in the first - order raman phonon scattering at higher frequencies , an additional broad band located at around @xmath43 cm @xmath44 , which can not be assigned to a normal symmetry mode , was present ( see fig . a weak band at the same frequency is distinguishable in the infrared spectra @xcite , which indicates that this excitation could be also weakly infrared - active due to the parity - breaking effect . this band is present in the raman spectra of all isovalent mn@xmath2 rare - earth @xmath3mno@xmath0 ( @xmath3=la , pr , nd , sm , eu , gd , tb , dy , ho , y ) oxides around the same frequency @xcite , demonstrating its general nature . as follows from our polarisation spectra , displayed in fig . 1(a - c ) , the excitation at 650 @xmath1 is not a single mode ; it is composed of @xmath40 symmetry modes . these could be the zone - boundary phonons , activated by disorder , which inevitably exists in these materials due to the presence of cation vacancies @xcite . _ associates the raman feature at 650 @xmath1 with the maximum in the phonon density - of - states ( pdos ) of oxygen vibrations , accordingly to polarisation properties and predictions , based on lattice - dynamics calculations @xcite . however , further we show that the origin of this band may be more complicated . the close - up of the first - order peak at 650 @xmath1 and the raman spectra in the second order , separated from the one - phonon lattice - symmetry raman modes and the background , is shown in the inset of fig . an extended structure , represented by the three broad features , is developed in the second order , which reveals strong polarisation dependence , so that only one broad feature of @xmath28 symmetry is pronounced in the @xmath18-polarised spectra . in the earlier raman study by saitoh _ _ of a detwinned lamno@xmath0 crystal , these three broad features observed at around 1008 , 1170 , and 1290 @xmath1 were considered as a result of the dispersion of an independent orbital excitation , induced by the superexchange interaction @xcite . here we investigated in detail temperature and polarisation dependencies of the anomalous first- and second - order raman scattering and found them dependent due to a common origin . figure 3(a ) shows the frequencies of the first - order peak at around 650 @xmath1 multiplied by two and the second - order peak at around 1290 @xmath1 . a nearly one - to - one correspondence between these two frequencies in the temperature - dependent spectra of @xmath28 symmetry in the @xmath18 polarisation was observed . however , apparently they do not coincide in the @xmath41 and @xmath38 polarisations as the frequencies of the first - order peak multiplied by two appear to be shifted by approximately 25 @xmath1 higher with respect to the frequencies of the second - order peak ( see also the inset to fig . 1(b ) , where the first- and second - order spectra are clearly delineated ) . at the same time , there is a clear correlation in the temperature dependencies of their peak positions , although we show a different trend in the temperature dependence in the @xmath41 polarisation , which seems to demonstrate a softening - like behaviour , analogous to that of the @xmath32 ( 606 @xmath1 ) mode below the nel temperature ( see fig . 2(a ) ) . additionally , the widths of the first- and second - order peaks fall in the same range within the experimental error bars in the @xmath38 and @xmath18 polarisations ( see fig . the estimated coefficient in a linear approximation of the fwhm temperature dependence is about 0.06 @xmath9 0.01 @xmath1/k in the studied temperature range , comparable to that of the first - order jt @xmath28 ( 495 @xmath1 ) and @xmath32 ( 606 @xmath1 ) modes . this is indicative that the anomalous scattering observed in the @xmath38 and @xmath18 polarisations has essentially phononic character and could be associated with the maximum in the phonon density - of - states ( pdos ) of oxygen vibrations @xcite . surprisingly , the temperature dependence of the fwhm of the first - order peak at 650 @xmath1 , and its second - order replica at 1290 @xmath1 , show very different behaviour in the @xmath41 polarisation , where the temperature coefficient of the linear temperature dependence is about 0.18 @xmath9 0.02 @xmath1/k . figure 3(c ) shows temperature and polarisation dependencies of the scaled integrated intensities of the first - order peak at 650 @xmath1 and the second - order peak at 1290 @xmath1 , which exhibit the same trends as that of the @xmath28 and b@xmath45 phonons ( see fig . 2(c ) ) . and finally , fig . 4 shows the raman spectra measured in the multiphonon spectral range on our detwinned lamno@xmath0 crystal in the @xmath38 polarisation at @xmath46= 80 k. the spectra in the multiphonon range were observed on a background of a broad lorentzian band ( located at around 870 cm @xmath44 , with fwhm of about 1300 @xmath1 ) . the spectra were fitted with a set of lorentzians , accounting for the clearly resolved intensity peaks , and the result of the fit is shown in fig . 4 . the inset shows the result of the fitting of the raman spectra in the multiphonon spectral range , subtracted from the contributions of the first - order lattice raman phonons and the background . according to this analysis of our raman data , the multiple excitations appear with a period of about 630 @xmath1 up to the fourth order ; and , since we have unveiled that the first- and second - order raman scattering have a common origin , and the excitation observed in the first order at around 655 @xmath1 must be shifted by about 25 @xmath1 from the central laser line . this is consistent with our analysis presented in fig . the ratio between the two main peaks in the periodically repeated three - peak structure changes progressively in the multi - order scattering , from the dominating higher - frequency feature in the second - order process to the opposite case in the fourth - order process , whereas the two features are approximately equal in the third - order process . this might be associated with a progressive decrease of the @xmath28 contribution at 650 @xmath1 in the higher - order spectra , as observed in the second - order process ( see the inset of fig . 1(b ) ) , where the decreased @xmath28 contribution at around 1300 @xmath1 against the enhanced relative contribution of @xmath32 symmetry at around 1165 and 1285 @xmath1 can be observed . from this follows that the anomalous raman scattering is essentially promoted by the @xmath32 mode at 510 @xmath1 , which appears periodically at around 1165 , 1795 , and 2425 @xmath1 in the multiple - order spectra . we have investigated a detailed temperature dependence of the first and higher - order raman scattering in the detwinned lamno@xmath0 crystal and , based on the results of this study , we can conclude that the multi - order raman scattering arises from the series of transitions , and that the triplet structure observed in the raman spectra in the 900 1400 @xmath1 range is the second replica in the series . this is in contrast to the conclusions of saitoh _ et al . _ @xcite , where the three peaks observed in the 900 1400 @xmath1 range at around 1008 , 1170 , and 1290 @xmath1 were previously interpreted as a result of dispersion of an independent orbital excitation , related to the superexchange interaction . we show that the triplet structure , being shifted from the zero frequency by about @xmath47 25 @xmath1 in the @xmath38 polarisation , is repeated in the multi - order spectra with a period of @xmath48 630 @xmath1 . in this case , the three pronounced excitations ( numerated by @xmath49=1,2 , and 3 ) in the n@xmath50-order raman spectra ( @xmath51=1,2,3,4 , .. ) can be represented as @xmath52 . for the @xmath38-polarised spectra , measured on our detwinned lamno@xmath0 crystal ( see fig . 4 ) , we determine @xmath48 630 @xmath1 , @xmath53 510 @xmath1 , and @xmath54 320 @xmath1 . we note that in the valid multiphonon scenario @xcite , a sum of the @xmath55 vectors of the phonons involved in the raman scattering at @xmath56 must be @xmath57 . to satisfy these conditions , all the phonons , @xmath58 , @xmath59 , @xmath60 , and @xmath61 , must be the zone - center phonons . however , we can not find the @xmath62-point raman and/or infrared mode at @xmath48 630 @xmath1 @xcite . thus , we assume that the observed effect may result from combinations of other phonons from the brillouin zone , provided their total @xmath55 vector @xmath57 . it has been suggested by iliev _ _ that the feature at around 650 @xmath1 , replicated in the multi - order raman scattering , corresponds to the maximum of the phonon density - of - states ( pdos ) of oxygen vibrations , which is in good agreement with the lattice - dynamics theoretical calculations @xcite . according to the results of our raman study on the detwinned lamno@xmath0 crystal in the multiphonon spectral range , we propose that the pdos feature has a period of @xmath48 630 @xmath1 in the @xmath38 polarisation , and that the strong peak at @xmath53 510 @xmath1 is dominated by the contribution from the zone - boundary @xmath32 phonons to the pdos . we still need to provide an explanation for the shift of the multi - order raman scattering from the zero frequency by @xmath47 25 @xmath1 , observed in this study ( see fig . 4 and the inset ) . we suggest that this shift could result from a low - energy mode , allowed by symmetry ; in this case , the periodically repeated oxygen pdos feature with a period of @xmath48 630 @xmath1 could be sidebands , activated by some process , and not allowed by symmetry . if this is true , one should be able to observe the low - energy mode at @xmath47 25 @xmath1 in a far - infrared experiment . we are aware of the experimental evidence of the mode at about 25 @xmath1 in doped rare - earth manganites . in pr@xmath63ca@xmath64mno@xmath0 the observed low - energy absorption peak at 16 24 @xmath1 was assigned to a collective excitation of the charge - density - wave state @xcite . this hypothesis , however , was challenged in a recent study of the low - energy excitations in la@xmath65ca@xmath66mno@xmath0 , where a resonance - like absorption observed at about 25 @xmath1 was associated with the optically activated acoustic phonon due to a fourfold superstructure along the @xmath67 axis in the charge - ordered state below @xmath68 k @xcite . however , the low - energy mode observed in la@xmath65ca@xmath66mno@xmath0 at around 25 @xmath1 appears at temperatures below @xmath69 k @xcite and seems to be not directly related to the formation of the charge - ordered state in the doped manganites . a far - infrared - active broad relaxation - like mode , excited by the @xmath41-polarised electric a.c . component of the radiation at about the same frequency in multiferroic manganites tbmno@xmath0 ( at 20 @xmath9 3 @xmath1 ) and gdmno@xmath0 ( at 23 @xmath9 3 @xmath1 ) , was ascribed to an electro - active magnon excitaton @xcite . the mode intensity increases with decreasing temperature in the low - temperature magnetic phase , where it can be suppressed by an external @xmath18-axis polarised magnetic field of an order of several tesla @xcite . in multiferroics of more complex mixed - valence manganites of @xmath3mn@xmath22o@xmath70 ( @xmath3=pr , sm , gd , tb ) a strong featureless band around these frequencies in the infrared reflectivity spectra was associated with collective electronic excitations of partially delocalised @xmath4 electronic orbitals , participating in dynamical multiferroic coupling in the jahn - teller distortion of the pyramid dimer @xcite . the transmission measurements detected this mode in tbmn@xmath22o@xmath70 and ymn@xmath22o@xmath70 at 9.6 @xmath1 and 7.2 @xmath1 , respectively @xcite . additionally , the high - frequency mode , corresponding to the raman mn - o stretching mode , appears in the infrared spectra at the ferroelectric transition in tbmn@xmath22o@xmath70 @xcite . these experimental evidences certify that the low - energy mode gains its spectral weight and becomes activated in doped rare - earth manganites and mn - based multiferoics . the anomalous raman scattering was also observed in the mixed @xmath71-site orthorhombic perovskites of lafe@xmath72cr@xmath73o@xmath0 , activated by the photon - induced electronic charge transfer between the neighbouring transition - metal ions of cr@xmath2 ( 3@xmath74 ) and fe@xmath2 ( 3@xmath75 ) @xcite . the observed anomalous raman scattering was shown to be critically dependent on the presence of both @xmath71-site type cations , as well as the doping level , in this system with strong electron - phonon interaction , locally disturbing coherence in the electronic and vibronic structure @xcite . in a view of the results obtained in the present study , it will be interesting to look for the infrared - active low - energy mode in the mixed @xmath71-site orthorhombic perovskites of lafe@xmath72cr@xmath73o@xmath0 . we argue that the low - energy mode at @xmath47 25 @xmath1 could be a tunneling transition in lamno@xmath0 , and the periodically repeated oxygen pdos feature with a period of @xmath48 630 @xmath1 could be the sidebands , activated by the electron tunneling between the potential energy minima generated near the jt mn@xmath2 ion by the lattice anharmonicity . indeed , first of all , we note that the frequency of the mode at around 25 @xmath1 is consistent with the tunneling frequencies in the dynamic limit of the jahn - teller effect in , for example , a @xmath19d system of 3 @xmath20 mgo : cu@xmath10 and 3 @xmath21 caf@xmath22 : sc@xmath10 @xcite . secondly , in our recent optical study of lamno@xmath0 we have established that the kinetic energy changes of the @xmath4 electrons from the low- to high - temperature limit , associated with the high - spin @xmath76 electronic transition , seen in the optical spectra at 2 ev , is about 55 mev @xcite . this energy is comparable with the orbital ordering temperature , @xmath77 = 780 k = 65 mev , and much higher than the energy of the average lattice anharmonicity barriers between the potential energy minima of about 100 @xmath1 ( 12 mev ) . therefore , the superexchange interaction may be crucial in driving the @xmath4 electrons to the regime of the dynamic jt effect , with affordable barriers for the tunneling between the potential energy minima . finally we note that the dynamic regime of the jahn teller effect could result in the anomalous multi - order raman scattering in manganites . indeed , we have discovered in the present study that aside from the oxygen - phonon density - of - states feature , there is an additional component to the multi - order scattering , which exhibits a different behavior . this character may arise from an admixture of the electronic component in the case of mixing between the electronic and vibrational states . for a weak vibronic interaction , when the barriers between the minima are less than the characteristic vibrational energy , a special coupling between low - frequency electronic motions and vibrational modes takes place @xcite . in the linear approximation , the eigenvalues of the system are those of a doubly - degenerate harmonic oscillator , @xmath78 , where @xmath51 is a positive integer and the @xmath79 level is ( @xmath51 + 1)-fold degenerate . in the second order of the perturbation theory , the degeneracy can be removed and all levels , except the ground state level with @xmath51=0 , become split . this splitting is similar to the effect of spin - orbit interaction in diatomic molecules , where for each @xmath51 there is the degeneracy with @xmath80 . further experiments are needed to investigate and verify the origin of the low - energy mode at about 25 @xmath1 and the low - energy electron - vibronic coupling in manganites , which is indicative of the dynamic regime of the jahn teller effect in manganites . the authors acknowledge helpful discussions with m cardona , k p meletov , and . this work was supported by the esf network - program aqdjj , the royal society of london ( grant jp 090710 ) , the russian foundation for basic research ( projects10 - 02 - 92600-ko and 11 - 02 - 00708 ) , program of the presidium ras `` quantum mesoscopic and disordered systems '' , grant ta01010517 of the tacr ( technology agency of the czech republic ) , and av0z10100522 of the ascr ( academy of sciences of the czech republic ) . 99 surface of the detwinned lamno@xmath0 crystal , with the incident laser light polarised along ( a ) the @xmath38 direction rotated by 45@xmath39 with respect to the main axes , ( c ) the @xmath18 axis . ( b ) the low - temperature ( 80 k ) raman spectra measured in the @xmath82 and @xmath18 polarisations and normalised to the @xmath28 ( 495 @xmath1 ) mode are shifted along the vertical axis . inset : the zoom - in of the polarised first - order raman spectra ( separated from the symmetry - allowed lattice phonons ) and the second - order raman spectra.,width=453 ] and @xmath32 modes , resulting from the fit of the raman spectra with lorentzian bands . solid curves in panels ( a , c ) are the guidelines for the dependencies averaged within the error bars . temperature dependences of the fwhm of the jt @xmath28 and @xmath32 modes in ( b ) are fitted by the linear functions.,width=491 ] and the second - order peak at about 1290 @xmath1 , resulting from the fit of the raman spectra with lorentzian bands : ( a ) the resonant frequencies of the first - order peak multiplied by two are compared with those of the second - order peak , ( b ) full widths at half maximum ( fwhm ) are fitted by the linear temperature dependences , and ( c ) scaled integrated intensities . solid curves in panels ( a , c ) are the guidelines for the dependences averaged within the error bars.,width=472 ] -polarised raman spectra , measured in the multiphonon range on the detwinned lamno@xmath0 crystal at t = 80 k ( green curve ) . the solid curve , superimposed with the raman spectra , demonstrates the accuracy of the fitting with the lorentzian bands . inset : the result of the fitting , subtracted from the wide background and the first - order raman lattice phonons . the multiple excitations appear with a period of 630 @xmath1 up to the fourth order , being shifted from the zero frequency by about 25 @xmath1.,width=434 ]

the multi - order raman scattering is studied up to a fourth order for a detwinned lamno@xmath0 crystal . based on a comprehensive data analysis of the polarisation - dependent raman spectra , we show that the anomalous features in the multi - order scattering could be the sidebands on the low - energy mode at about 25 @xmath1 . we suggest that this low - energy mode stems from the tunneling transition between the potential energy minima arising near the jahn - teller mn@xmath2 ion due to the lattice anharmonicity , and the multi - order scattering is activated by this low - energy electronic motion . the sidebands are dominated by the oxygen contribution to the phonon density - of - states , however , there is an admixture of an additional component , which may arise from coupling between the low - energy electronic motion and the vibrational modes .

autoimmune hepatitis ( aih ) patients usually present elevated serum aminotransferase levels ( 310-fold increase ) , marked hypergammaglobulinemia ( typically igg ) , positive titers of autoantibodies , histological findings of interface hepatitis and portal plasma cell infiltration , although atypical cases also exist [ 2 , 3 , 4 ] . typical primary biliary cirrhosis ( pbc ) patients are females in the age range of 3065 years , presenting with biochemical signs of cholestasis and the presence of antimitochondrial antibody ( ama ) , and they are asymptomatic or suffer from fatigue or pruritus [ 5 , 6 , 7 , 8 , 9 ] . diagnosis can be made in patients who have elevated alkaline phosphatase ( alp ) levels of at least 6 months duration , in combination with the presence of ama ( 1:40 ) . serum aminotransferase levels usually are only slightly elevated , whereas igm concentration is typically increased . some patients within the spectrum of autoimmune liver disease present with characteristics of both pbc and aih and are commonly classified as having an overlap syndrome [ 5 , 10 ] . in aih patients , ama is occasionally seen at low titers , but an ama anti - pyruvate dehydrogenase complex - e2 ( ama - m2 ) pattern , which is specific to pbc , is rarely detected . overlap cases are usually selected either on the basis of biochemical and serological findings or of histological features , although limitations due to biopsy size and sampling error should always be kept in mind in the assessment of a liver biopsy . the acute and fulminant forms of aih were recognized by the international autoimmune hepatitis group in 1992 , when it codified diagnostic criteria and waived the requirement for 6 months of disease activity to establish the diagnosis [ 1 , 4 ] , although it is still difficult to diagnose and treat the acute and fulminant forms of aih [ 2 , 4 , 12 ] . we present a case of acute liver failure with overlap features of both pbc and aih who was successfully treated with corticosteroids without liver transplantation . a 63-year - old japanese man was referred to chiba university hospital at the end of april 2011 for the treatment of acute liver failure . blood tests showed serum alanine aminotransferase ( alt ) 2,415 iu / l , aspartate aminotransferase ( ast ) 3,253 iu / l , alp 804 iu / l , total bilirubin 12.7 mg / dl , and prothrombin time international normalized ratio 1.65 . two weeks earlier , liver dysfunction had first been diagnosed at his regional clinic . at that time his medical history consisted of mild cerebral infarction 8 years before and surgery for inflammation of the right middle ear in his twenties . he had been taking medicines such as fenofibrate , allopurinol , diclofenac sodium , valsartan , nilvadipine and aspirin for hyperlipidemia , hyperuric acid , lumbar herniated disk and hypertension for more than 1 year . he occasionally drank alcohol and had no family history of liver diseases or autoimmune disorders . computed tomography showed minimal ascites and mild hepatosplenomegaly with a thickened gall bladder wall ( fig . doppler ultrasound color flow imaging showed inversion of venous flow , suggesting portal hypertension , although endoscopic findings did not reveal any esophageal or gastric varices . possible reactivation of herpes simplex virus and drug - induced liver injury were not completely ruled out at that time . because of the positivity for antinuclear antibody and ama , especially ama - m2 , we considered him to have autoimmune liver disease such as aih or overlap syndrome with characteristics of both pbc and aih , and so the administration of corticosteroids was initiated . he was first treated with 1,000125 mg of methylprednisolone daily for 10 days , and then with 605 mg prednisolone daily for approximately 110 days . total bilirubin continued to rise up to 31.2 mg / dl , but then recovered . after his discharge , he was treated daily with 5 mg of prednisolone and 600 mg of ursodeoxycholic acid . during his hospitalization , 70 days after the start of corticosteroid treatment , transjugular liver biopsy the liver biopsy specimen showed the architecture of the liver as being preserved , indicating no cirrhosis , but revealed submassive hepatic necrosis , findings compatible with overlap syndrome with characteristics of both pbc and aih . the aih score was 16 after completion of corticosteroid treatment , pointing to aih compatibility . his liver function tests were improved ( alt 11 iu / ml , ast 22 iu / ml , total bilirubin 0.6 mg / dl , igm 166 mg / dl , and igg 1,176 mg / dl ) , but his antinuclear antibody and ama were still positive . we present a 63-year - old japanese man with acute liver failure and positivity for ama - m2 who was successfully treated with corticosteroids . before admission he had no symptoms , and alp however , alp levels were still elevated in mid - october 2011 , ama - m2 was still positive ( 8 iu / ml ) , and he had intractable pruritus , suggesting that pbc also existed . pbc - aih overlap syndrome is a clinical entity characterized by the occurrence of both conditions at the same time in the same patient . we and others previously reported the consecutive occurrence of aih and pbc [ 9 , 13 ] . it is very important for patients with acute liver failure such as the present case to be treated as soon as possible . we used corticosteroid therapy and made preparations for urgent liver transplantation [ 14 , 15 ] . corticosteroids may be associated with a significant worsening of osteoporosis in patients with pbc [ 5 , 6 , 7 ] . we previously reported that corticosteroids are effective for aih with acute presentation and that they are also effective for overlap syndrome having aih and pbc features with acute transaminase elevation . indicated that there is a point beyond which aih can not be salvaged by drug therapy , and this point can be defined only by assessing the immediate response to corticosteroid treatment . this assessment can be made over a 2-week interval , which is sufficiently short to avoid the infectious complications associated with protracted immunosuppressive therapy and liver failure [ 4 , 12 ] . in our case , corticosteroid therapy remains appropriate for severe , immediately life - threatening and fulminant aih , although the treatment should be limited to 2 weeks or less . we present a case of acute liver failure with overlap features with both pbc and aih , who was successfully treated with corticosteroids without liver transplantation . in conclusion , it seems important to finely judge the corticosteroid use for atypical cases of autoimmune liver diseases with acute presentation over shorter periods .

antimitochondrial antibody ( ama ) is one of the representative features of primary biliary cirrhosis ( pbc ) . pbc is a female - dominant disease usually presenting intrahepatic bile duct destruction , cholestasis and fibrosis with or without chronic nonsuppurative destructive cholangitis . we presented the case of a 63-year - old man with acute liver failure who had ama , pronounced alanine aminotransferase elevation and high bilirubinemia . we administered corticosteroids and rescued this patient without liver transplantation . it is well known that some patients within the spectrum of autoimmune liver disease present with characteristics of both pbc and autoimmune hepatitis . although corticosteroids may be associated with a significant worsening of adverse events in patients with pbc , if acute liver failure in ama - positive cases is progressive , the administration of corticosteroids has to be considered , as well as the preparation of urgent liver transplantation .

soccer is one of the most popular sports in the world . a variety of age groups , from youth to senior , play it1 , 2 . soccer is a team sport played for at least 8090 minutes in official games3 . the game requires a high level of skill and stamina , and participants tend to show particular physical and physiological characteristics4 . soccer players are divided into four playing positions : forward ( fw ) , midfielder ( mf ) , defender ( df ) , and goalkeeper ( gk ) . the gk , in particular , has the lowest activity in the game and the shortest activity distance5 . many studies have examined the different physical and physiological characteristics of soccer players based on playing position3 , 4 , 6 . heath and carter determined somatotype by measuring body size , width of bone , and thickness of skin . heath - carter s classification can be applied to youth soccer players . by evaluating the somatotypes of youth soccer players , the effect of their sport can be seen . furthermore , the body compositions of athletes of each sport are different , depending on the characteristics of the sport . the adaptation to physical effort , developed during training and the process of selection , results in a decrease of somatotype and body composition diversity among athletes in similar sports or using similar skills15 , 16 . a great deal of research is being done on the physical characteristics of soccer players . however , the study of youth soccer players , especially korean , is limited . our study measured the physical characteristics of korean youth soccer players to establish a reference for the study of training and injury rehabilitation of youth soccer players . the subjects were 22 korean youth soccer players with no physical or psychological conditions . the participants also completed a questionnaire in an individual in - depth interview , which took 20 to 30 minutes per person17 . the characteristics of the participants are shown in table 1table 1.characteristics of korean youth soccer playersvariablekorean youth soccer playersage ( yrs)16.3 0.1gendermale ( % ) 22 ( 100.0)female ( % ) -height ( cm)176.5 1.0weight ( kg)68.3 1.3bmi ( kg / m)21.9 0.3career ( yrs)7.1 0.4training time3.8 0.3 h / day20.8 1.6 h / weekpositionforward ( % ) 6 ( 27.3)midfielder ( % ) 6 ( 27.3)defender ( % ) 8 ( 36.4)goalkeeper ( % ) 2 ( 9.1)somatotype ( dominant type)endomorphy ( % ) -mesomorphy ( % ) 8 ( 36.4)ectomorphy ( % ) 12 ( 54.5)central ( % ) 2 ( 9.1)endomorphic component2.0 0.1mesomorphic component2.6 0.2ectomorphic component3.1 0.1data are presented as means se . the characteristics of the youth soccer players according to playing position can be found in fig . endo , endomorphy ; meso , mesomorphy ; ecto , ectomorph and table 2table 2.differences in somatotype among the positions of the korean youth soccer playersvariablepositions of the korean youth soccer playersforward ( fw)midfielder ( mf)defender ( df)goalkeeper ( gk)number ( % ) 6 ( 27.3)6 ( 27.3)8 ( 36.4)2 ( 0.9)height ( cm)173.7 0.5174.2 1.1177.6 1.6187.0 1.0weight ( kg)64.1 1.867.3 0.968.9 1.581.4 3.5bmi ( kg / cm)21.3 0.522.2 0.521.9 0.523.3 0.83 somatotypeendo ( % /%)----meso ( % /%)2 ( 33.3/9.1)3 ( 50.0/13.6)2 ( 25.0/9.1)1 ( 50.0/4.5)ecto ( % /%)4 ( 66.7/18.2)2 ( 33.3/9.1)5 ( 62.5/22.7)1 ( 50.0/4.5)central ( % /%)-1 ( 16.7/4.5)1 ( 12.5/4.5)-endo c.1.8 0.22.2 0.21.9 0.22.3 0.3meso c.2.4 0.32.9 0.22.5 0.32.9 0.5ecto c.3.2 0.22.8 0.33.2 0.33.0 0.313 somatotypetypes ( % /%)bec 2 ( 33.3/9.1bm 2 ( 33.3/9.1)bec 3 ( 37.5/13.6)bec 1 ( 50.0/4.5)ecm 2 ( 33.3/9.1)bec 1 ( 16.7/4.5)mec 2 ( 25.0/9.1)bm 1 ( 50.0/4.5)mec 1 ( 16.7/4.5)mec 1 ( 16.7/4.5)ecm 1 ( 12.5/4.5)enec 1 ( 16.7/4.5)enm 1 ( 16.7/4.5)m - en 1 ( 12.5/4.5)cen 1 ( 16.7/4.5)cen 1 ( 12.5/4.5)data are presented as the mean se . bmi , body mass index ; endo c , endomorphic component ; meso c , mesomorphic component ; ecto c. ectomorphic component ; bec , balanced ectomorph ; ecm , ectomorphic mesomorph ; mec , mesomorphic ectomorph ; enec , endomorphic ectomorph ; bm , balanced mesomorph ; enm , endomorphic mesomorph ; cen , central type ; m - en , mesomorph - endomorph . : p < 0.05 .. the subjects wore only shorts for the measurements , and the measurements were taken by a single person . before being measured then the girths ( flexed and tensed ) of the upper arm and thickest part of the calf were determined with a tape measure . the breadths of the biepicondylar humerus and biepicondylar femur were measured with a large anthropometer . finally , skinfold thicknesses of the triceps brachii , subscapular , superior iliac , and calf were determined with a medical skinfold caliper ( jamar , usa ) . the somatotypes were classified as endomorphic , mesomorphic , ectomorphic , and balanced types , according to heath - carter s modified somatotype method , and further broken down into thirteen subcategories . balanced endomorphs have a dominant endomorphic component , and the values the mesomorphic and ectomorphic components do not differ by more than 0.5 . mesomorphic endomorphs have a dominant endomorphic component , and the mesomorphic component is higher than the ectomorphic component . mesomorph - endomorphs mesomorphic and endomorphic components do not differ by more than 0.5 , and the ectomorphic component is lower than the other values . endomorphic mesomorphs have a dominant mesomorphic component , and the endomorphic component is higher than the ectomorphic component . balanced mesomorphs have a dominant mesomorphic component , and the values of the endomorphic and ectomorphic components do not differ by more than 0.5 . ectomorphic mesomorphs have a dominant mesomorphic component , and the ectomorphic component is higher than the endomorphic component . mesomorph - ectomorphs by between their mesomorphic and ectomorphic components do not differ by more than 0.5 , and the endomorphic component is lower than the other values . mesomorphic ectomorphs have a dominant ectomorphic component , and the mesomorphic component is higher than the endomorphic component . balanced ectomorphs have a dominant ectomorphic component , and the values of the endomorphic and mesomorphic components do not differ by more than 0.5 . endomorphic ectomorphs have a dominant ectomorphic component , and the endomorphic component is higher than the mesomorphic component . endomorph - ectomorphs endomorphic and ectomorphic components do not differ by more than 0.5 , and the mesomorphic component is lower than the other values . ectomorphic endomorphs have a dominant endomorphic component , and the ectomorphic component is higher than the mesomorphic component ) . lastly , central types do not differ by more than 1 among the components values7,8,9 . bmi , body mass index somatcharts of the playing positions of the elite korean youth soccer players . endo , endomorphy ; meso , mesomorphy ; ecto , ectomorph data are presented as the mean se . bmi , body mass index ; endo c , endomorphic component ; meso c , mesomorphic component ; ecto c. ectomorphic component ; bec , balanced ectomorph ; ecm , ectomorphic mesomorph ; mec , mesomorphic ectomorph ; enec , endomorphic ectomorph ; bm , balanced mesomorph ; enm , endomorphic mesomorph ; cen , central type ; m - en , mesomorph - endomorph . : p < 0.05 . the heath - carter formula using our study is as follows:1 ) endomorphic component= 0.7182 + 0.1451 sf 0.00068 sf + 0.0000014 sfsf = ( sum of skinfold thickness of triceps brachii , subscapular , and superior iliac ) [ 170.18/height ( cm)]2 ) mesomorphic component= 0.858 breadth of biepicondylar humerus + 0.601 breadth of biepicondylar femur + 0.188 modified girth of upper arm + 0.161 modified girth of calf height 0.131 + 4.5modified value is [ value ( 1/10 skinfold thickness)]3 ) ectomorphic componentthe ectomorphic component is the difference according to the value of the height - weight ratio ( hwr , hwr = height / weight).hwr 40.75 = 0.732 hwr 28.5838.25 < hwr < 40.75 = 0.463 hwr 17.63hwr 38.25 = 0.1the formula marked on the somatotype chart is as follows : x = ectomorphic component endomorphic componenty = 2 mesomorphic component ( endomorphic com ponent + ectomorphic component ) to confirm body composition , a 4-pole-8-pole contact electrical method was used2 , 14 . the lean body mass , fat free mass , fat mass , and basal metabolic rate of the participants were measured using a precision body composition analyzer ( inbody 520 , biospace , korea ) . statistical analyses were conducted using the sas software ( version 6.12 ) to calculate averages and standard deviations . the data were expressed as mean standard error ( se ) of the measurements . a significance level of = 0.05 was chosen when performing the independent t - test for group comparisons . the protocol for this study was approved by the committee of ethics in research of the university of yongin , in accordance with the terms of resolution 5 - 1 - 20 , december 2006 . the general characteristics of the twenty - two youth soccer players are noted in table 1 . some variation in the characteristics of somatotype was observed among the playing positions ( table 2 ) . the dfs were taller than the fws and mfs , but had physical characteristics similar to the other field players . while gks were taller and heavier than the other players their somatotype components were not significantly different from those of the other players ( table 2 ) . on the somatotype chart , the subjects are all located slightly to the left side ( the ectomorphic side ) , regardless of the players positions ( fig . the participants consisted of twelve ectomorphic , eight mesomorphic , and two central predominant types . subdividing the youth soccer player s somatotypes resulted in seven balanced ectomorphs , four mesomorphic ectomorphs , three ectomorphic mesomorphs , three balanced mesomorphs , two central types , one endomorphic ectomorph , one endomorphic mesomorph , and one mesomorph - endomorph ( table 2 ) . lbm , ffm , fm , bf , and bmr were not significantly different among the field players . however , lbm , ffm , and bmr were significantly higher in gks than in fws and mfs ( table 3table 3.differences in body composition among the positions of the korean youth soccer playersvariablepositions of the korean youth soccer playersforward ( fw)midfielder ( mf)defender ( df)goalkeeper ( gk)lbm ( kg)35.5 1.336.7 0.538.2 0.945.6 2.3ffm ( kg)61.5 1.963.6 0.765.9 1.578.5 3.7fm ( kg)2.6 0.43.7 0.63.0 0.53.0 0.2bf ( % ) 4.0 0.65.5 0.94.4 0.73.7 0.4bmr ( kcal)1,698.8 42.11,743.0 16.31,793.8 33.22,064.0 79.0data are presented as the mean se . lbm , lean body mass ; ffm , fat - free mass ; fm , fat mass ; bf , body fat ; bmr , basal metabolism rate . : lbm , ffm , and bmr values among gks and dfs showed large differences but they were not statistically significant ( table 3 ) . lbm , lean body mass ; ffm , fat - free mass ; fm , fat mass ; bf , body fat ; bmr , basal metabolism rate . : p < 0.05 . we compared the somatotypes and body compositions of korean youth soccer players according to their playing positions . the dfs were taller than the other field players , but they were similar in other physical characteristics . the gks had higher values of height , weight , lbm , ffm , and bmr than the other players ; however , the bmi and somatotype components were not significantly different among the positions . although the gks were taller and more muscular than the other players , the ratio of their height to muscle was similar to that of the other positions . as a result , their somatotype components were not different from those of the other players . the somatotype components were not different among the playing positions , but fws and dfs had a greater difference between the ectomorphic and mesomorphic components . thus , fws and dfs were more likely to have a thin body type than mfs and gks . soccer players rely heavily on aerobic endurance due to the game s intermittent high intensity activity4 . as a result , our study showed that all the subjects had low body fat , and it was very low in comparison with non - players . according to a study of obesity in male asian college students , their body fat mass averaged 14.26 kg , and their percentage of body fat had a mean of 18.86%18 . while obesity rates are increasing , the typical korean youth soccer player has very lean body characteristics . studies of somatotype and physical characteristics of adult soccer players have reported that soccer players have a mesomorphic predominant somatotype3 , 4 , 19 . more than half the participants in our study had an ectomorphic predominant somatotype , and the remaining players had mostly mesomorphic body types , likely because youth soccer players have not reached their full growth . another study of young soccer players showed that they had a higher ectomorphic component value than older age groups20 . it has also been reported that adult soccer players have obviously different physical characteristics according to playing position6 , 21 . handball and basketball players have different physical characteristics for each playing position22 , 23 . however , the physical characteristics of youth soccer players in this study had no significant differences , except for the gks . thus , young field players should be able to change their position more easily than adult players . similar results were reported for the somatotypes and physical characteristics of zimbabwean youth soccer players24 . however , the subjects in the current study were taller than those in the zimbabwean study . thus , the zimbabwean youth soccer players had a higher mesomorphic component than the korean youth soccer players , despite the korean youths having a higher ffm value than the zimbabwean youths . the korean youth soccer players had ectomorphic and mesomorphic predominant somatotypes and very low body fat for their athletic performance . according to a study of minimizing injury rate in soccer players by somatotype , therefore , fat reduction and increased skeletal muscle mass would be beneficial for the safety of the young soccer players . in summary , korean youth soccer players tend to have lean builds with predominantly ectomorphic and mesomorphic somatotypes while adult soccer players have a predominantly mesomorphic somatotype . this allows younger soccer players more flexibility over the position they play than adult players . in addition , the injury rate of mesomorphic players is less than that of ectomorphic players , so the somatotype of the players should be considered during training . according to our data , we suggest that youth soccer players focus on reducing fat and building up skeletal muscle to prevent injury and aid in recovery . this study provides reference data of the physical characteristics of youth soccer players , but further research is needed to assist in the proper training of athletes returning from injury , and to support sports physiotherapy research .

[ purpose ] the purpose of this study was to investigate the somatotype and physical characteristic differences among elite youth soccer players . [ subjects and methods ] in the present study , we evaluated twenty - two korean youth soccer players in different playing positions . the playing positions were divided into forward ( fw ) , midfielder ( mf ) , defender ( df ) , and goalkeeper ( gk ) . the participants lean body mass ( lbm ) , fat free mass ( ffm ) , fat mass ( fm ) , and basal metabolic rate ( bmr ) were measured and their somatotype determined according to the heath - carter method . [ results ] the youth soccer players had twelve ectomorphic , eight mesomorphic , and two central predominant types . the dfs were taller than , but otherwise similar in physical characteristics to the fws and mfs . the gks were taller and heavier than the other players ; however , their somatotype components were not significantly different . lbm , ffm , and bmr were significantly higher in gks than in fws and mfs . although lbm , ffm , and bmr values between gks and dfs showed large differences , they were not statistically significant . [ conclusion ] the present study may contribute to our understanding of the differences in somatotype and body composition of korean youth soccer players involved in sports physiotherapy research .

parkinson 's disease ( pd ) affects approximately 0.3% of the population worldwide , and from 1% to 2% of individuals are more than 60 years old . in brazil , a recent population - based cohort study showed pd to have a prevalence of 3.3% . pd is a neurodegenerative pathology characterized by progressive degeneration of the dopamine - containing neurons in the substantia nigra pars compacta . the decreased amount of dopamine compromises the optimum amount of neuromotor impulses required for the accurate control of muscle activation . as a consequence , pd patients show motor disturbances ( e.g. , resting tremor , rigidity , postural instability , and gait disorders ) . the clinical parameters of pd patients tend to get worse progressively , even though therapeutic interventions have shown some benefits to patients [ 4 , 5 ] . the negative impact of gait disorders includes immobility ( causing loss of independence ) and the risk of falling . therefore , a large number of studies have been performed to measure gait parameters in pd patients . these studies have shown that parkinsonian gait is characterized by shortened step and stride length and reduced velocity [ 6 , 7 ] . while cadence typically is not modified , in some cases , as a possible adaptation to amplitude regulation disorder , it appears to increase . these gait features progressively worsen with the advance of the disease , which severely limits patients ' mobility and quality of life [ 8 , 9 ] . researchers have examined empirical studies to establish effective interventions that can improve the gait parameters of pd patients . for example , a recent meta - analysis revealed that exercise trials may promote benefits related to gait in pd patients . some studies achieved satisfactory results by applying specific exercise programs for locomotion ( e.g. , body - weight - supported exercises on a treadmill [ 11 , 12 ] , walking on a treadmill at a speed greater than overground walking speed , use of visual and auditory cues ) , for lower limb strength and for coordination and sensory attention [ 4 , 5 ] . thus , we can speculate that specificity of exercise is not a critical factor in improving gait parameters of pd patients . although promising , studies of exercise in pd have been limited in scope ( program duration and specificity ) . most have addressed the effects of short - term ( typically implemented over 4 to 12 weeks ) specific exercise programs . the benefits of longer and nonspecific exercise intervention remain poorly understood [ 16 , 17 ] . to our knowledge , this is the first study addressing the effects of a 6-month , multimodal exercise program on gait parameters in pd patients . our research group has previously demonstrated a positive effect of the purposed program on executive functions and balance . within this context , the current study employed a broader approach , one which utilizes a multimodal exercise program , in an attempt to improve the gait parameters of pd patients . in addition , many exercise trial studies have ignored the overall changes in symptoms or disease severity [ 18 , 19 ] . sage and almeida suggested that in exercise trials it is crucial for investigators to consider effects on clinical symptoms in conjunction with changes in gait . therefore , the aim of this study was to identify the effects of a 6-month , multimodal exercise program on clinical and kinematic gait parameters in pd patients . we expected to observe positive changes in pd patients ' symptoms and gait parameters after their participation in the program . this study adhered to the guidelines of the declaration of helsinki and was approved by the local ethics committee . the participants were recruited through the assistance of physicians ( neurologists and psychiatrists ) from rio claro , so paulo , brazil , who encouraged their patients to participate in the study . diagnosis of pd was made according to the united kingdom parkinson 's disease society brain bank clinical criteria for idiopathic pd . the participants were assigned to two groups according to personal interest ( the participants chose which group they preferred to be part of ) : trained group ( tg ; n = 24 ) and control group ( cg ; n = 10 ) . participants of both groups were sedentary prior to the study ( subjects had followed any training program during last year ) . individuals in the tg participated in a 6-month , multimodal exercise program described under the training protocol section . participants in the cg kept to their same daily routines and did not participate in any regular or structured exercise during the study period . table 1 shows demographic data at baseline for the 29 individuals who completed the study . inclusion criteria were disease in stages i iii of the hoehn and yahr rating scale ( h&y ) , independent walker , and no cognitive impairment , as judged by the mini - exam of mental status ( mems ) . 's suggestions for utilization of the mems in brazil ( cutoff score according to educational level ) were followed to screen for cognitive impairment . exclusion criteria were any history of orthopedic , cardiovascular , or psychiatric disorders , as judged by the clinical assessment . the aim of the multimodal exercise program was to develop the patients ' functional capacities , cognitive functions , posture , and locomotion . in contrast to specific programs , this one targeted a global ( holistic ) improvement of pd patients . it is composed of a variety of activities that simultaneously focus on other components of functional capacity , such as muscular resistance ( specific exercises for gastrocnemius , quadriceps femoralis , hamstring , rectus abdominalis , and trunk dorsal muscles ) , motor coordination ( rhythmic activities ) , and balance ( recreational motor activities ) . these components were selected because they seem to be affected by pd and could represent underlying mechanisms to gait impairments . the multimodal program took place over a 6-month period ( 72 sessions , 3 times a week , and 60 minutes per session ) . each session consisted of five parts ( warm - up , preexercise stretching , exercise session , cool down and postexercise stretching ) . the program was divided into six phases ; each phase was composed of 12 sessions , each lasting approximately one month . at the end of each phase there was a progressive increase of load ( table 2 ) . in each session , three different participants utilized a heart rate monitor ( polar ) to assess the intensity of the session . heart rate during the main exercise sessions remained between 60% and 80% of maximum heart rate ( 220 minus the participant 's age in years ) . each participant was required to participate in at least 70% of the sessions in order to be included in the data analysis . no participant of the tg was absent from the intervention program for more than five consecutive sessions . participants were tested before commencing the multimodal program ( pretest ) and upon completion ( posttest ) . all assessments were carried out in the morning , in the on - medication state , 1 hour after participants ' first morning dose of medication . a neuropsychiatrist performed a clinical assessment in order to test participants on the unified parkinson 's disease rating scale ( updrs ) , mems , and h&y . conversely , higher scores on the mems represent a more preserved cognitive function . for data analysis , scores on the updrs subsections i ( mentation , behavior , and mood ) , ii ( activities of daily living ) , and iii ( motor ) were considered separately . the rater was blinded as to the study purpose and to the groups in which the patients participated . the walking task required participants to walk , at a self - paced speed , on a pathway 8 m long by 1.4 m wide , which was covered with a black rubber carpet , 3 mm thick . three trials were performed . for the kinematic data recording , two passive markers ( reflective , adhesive styrofoam , 15 mm in diameter ) were attached to the following anatomic landmarks : lateral face of the right calcaneus and medial face of the left calcaneus . the images of the right sagittal plane of one stride at center of the pathway were recorded with a frequency of 60 hz by one digital camcorder ( jvc , gr - dvl 9800 ) , generating 2d kinematic data . the x and y coordinates for each marker were transformed into a metric system by means of a bidimensional reference system , with four control points , and with a length of 1478 mm and a height of 1480 mm . raw data were filtered using a low - pass , second - order digital butterworth filter , with a cutoff frequency of 5 hz in the matlab 6.5 environment . a matlab algorithm calculated the gait - dependent variables by manipulating the matrix created by the dvideow software . the following gait - dependent variables were calculated on the central right stride , from heel contact to the next heel contact : stride length , stride duration , stride velocity , cadence , double - support phase duration , single - support phase duration , and swing phase duration [ 25 , 26 ] . the values for each dependent variable of all three trials per participant were considered for statistical analysis . this particular set of gait parameters was chosen because it has been shown to be altered in pd and to be a sensitive tool to identify changes in gait after the enrolment in exercise programs [ 4 , 6 , 13 , 25 , 26 ] . the personnel conducting gait analyses were also blinded as to the study purpose and to the groups in which the patients participated . for all outcome measures , unrelated sample student 's t - tests were employed for between group comparisons at the baseline . multivariate analyses of variance ( manova ) were employed , including group ( trained versus control ) and time ( pretest versus posttest ) as factors , with repeated measures on the second factor . significant interactions were followed up with post hoc comparisons using tukey honestly significant difference ( hsd ) procedure . five participants in the tg dropped out of the study : three due to the time commitment , one moved to another city , and one died . thus , data from 19 individuals who completed the training protocol ( 10 women and 9 men ) and 10 control participants ( 4 women and 6 men ) were used for analysis . although the participants ' distribution procedure was not random , the two groups were not significantly different in demographic , clinical , and gait data at baseline . p values of t - tests are outlined in tables 1 , 3 , and 4 , respectively . the first manova did not reveal interactions between factors ( wilks ' lambda = 0.846 , f(5,23 ) = 0.840 , p = 0.535 ) for clinical variables . the second manova revealed interactions between factors ( wilks ' lambda = 0.838 , f(7,79 ) = 2.184 , p = 0.044 ) for gait variables . univariate analysis for interaction between groups and time revealed significant differences for stride length ( f(1,85 ) = 8.205 , p = 0.005 ) , and stride velocity ( f(1,85 ) = 9.290 , p = 0.003 ) , and trend for stride duration ( f(1,85 ) = 3.608 , p = 0.061 ) . tukey 's hsd post hoc test revealed that only the tg group had a statistically significant improvement of these gait parameters at posttest when compared with pretest . the aim of this pilot study was to identify the effects of a 6-month , multimodal exercise program on clinical and kinematic gait parameters in pd patients . primarily , it is important to attest that the applied intervention had no adverse event , which indicates that it could be carried out by people with pd in a safe manner . the current study brings a new approach to the possibilities that physical exercise can offer for rehabilitation in pd . the purposed multimodal exercise program has found improvement in some kinematic gait parameters , but not in clinical data , for the tg . although promising , these results should be interpreted with caution , as the current study has some important methodological limitations : ( i ) selection bias in the group assignment ; ( ii ) the lack of blinding of participants to group assignment ; ( iii ) sample size . regarding kinematic gait parameters , the proportional durations of stride phases and cadence did not change as an effect of the enrolment in the program . the main gait - related findings after participation in the program include improvements in stride length , stride duration , and stride velocity ( 7.7% , 8.5% , and 14% , resp . ) . the tg approached or reached the accepted means for brazilians healthy elderly individuals stride length : 117 cm ; stride duration : 0.99 s ; stride velocity : 120 cm / s . improvements in gait parameters have been shown to be of clinical relevance for elderly [ 28 , 29 ] , which would represent positive impact on quality of life . improvement in usual gait speed after a follow - up of one year predicts a substantial reduction in mortality . also , cesari et al . have suggested that usual gait speed of less than 1 m / s identifies persons at high risk of health - related problems ( persistent severe lower extremity limitation , death , and hospitalization ) in well - functioning older people . with this regard , it is important to note that the participants of tg have obtained a stride velocity value higher than this cutoff point at posttest . in addition to current findings , our group has previously demonstrated a positive effect of the purposed program on executive functions and on functional mobility and balance in pd patients . since multimodal exercise programs could have positive impact on motor and cognitive outcomes [ 16 , 17 ] , alves et al . found similar mean annual declines in the updrs - iii score and the h&y staging , at 3.1% and 3.2% , respectively . also , the updrs - ii score declined 3.5% per year . our findings do not point to a positive effect of purposed program over clinical data . it seems important to note that none of the clinical or gait parameters worsened for the cg in the study . it could be argued that six months does not represent enough time to observe significant declines in clinical or gait parameters of mild to moderate pd patients . thus , it is an important aspect to guide future long - term exercise trials : periods longer than six months should be considered . the rationale to choose a multimodal exercise intervention derived from the fact that the specificity of exercises is unclear relative to exercise trials in the rehabilitation literature for pd patients . researchers have had difficulty reaching a consensus on which type of exercise is most beneficial for gait parameters . for example , body - weight supported exercises on a treadmill ( three days a week for four weeks ) resulted in significant gait and symptom improvements . walking on a treadmill at a speed greater than overground walking speed ( three times per week for eight weeks ) was also efficient in ameliorating gait parameters such as walking speed , stride length , and cadence . employed visual and auditory cues , as well as verbal instructions ( three times per week for six weeks ) , which appeared to help increase the stride length of pd patients . the use of resistive training for lower limbs and abdominal muscles ( twice a week for eight weeks ) reveals a significant increase in stride length and velocity . sage and almeida [ 4 , 5 ] demonstrated that sensory , attention - focused exercise ( three days a week for 12 weeks ) can benefit the symptoms and gaits of pd patients . in this context , we can speculate that specificity of exercise is not a critical factor in improving gait parameters . all of these exercise trials were designed specifically to improve gait parameters and had short - term durations ( between 4 and 12 weeks ) . however , we suggest that pd patients should be enrolled in exercise programs for long periods ( at least for 24 weeks ) , and that such programs also should attempt to correct a range of impairments caused by pd , which ultimately could result in improvements for quality of life . our findings suggest that this could be possible with a 6-month , multimodal exercise program . in addition , long - term exercise programs could provide another benefit : fighting against disease progression ( protective effect of exercise ) . over short periods , it is difficult to assess the effects of exercise related to the progression of pd . this is supported by the fact that exercise studies of an animal model of pd have demonstrated increased survival of nigrostriatal dopaminergic neurons , suggesting a potential protective effect of exercise as well . therefore , it may be argued that these benefits could be achieved by a physically active lifestyle . it would be useful to design other studies to help improve the understanding of how exercise trials affect the gait parameters of pd patients . future long - term exercise trials should include midpoint assessment to verify specific short- and long - term exercise - related changes on clinical and gait parameters . it could also be useful to review walking tasks that are utilized to evaluate gait . for example , walking on a treadmill or on a walkway is different than walking in domestic and community environments . locomotion over uneven terrains ( obstacle crossing task ) , or under postural threat ( constrained and elevated floor ) , is a more complex tasks and should be explored relative to pd patients enrolled in exercise programs . in conclusion , the purposed 6-month , multimodal exercise program has found improvement in some kinematic gait parameters of mild - to - moderate idiopathic pd patients . further study in the form of a randomized controlled trial would be required to establish effectiveness of our program .

this pilot study aimed to identify the effects of a 6-month , multimodal exercise program on clinical and gait parameters in patients with parkinson 's disease . two groups of participants were enrolled in the study : trained group ( tg ) and control group ( cg ) . individuals in the tg exercised three times a week for 24 weeks ( in a multimodal exercise program ) , while the cg participants maintained their regular activity level . participants in both the tg and the cg were assessed at pre- and posttest by clinical rates and the spatiotemporal parameters of self - paced walking . the two groups were not significantly different in demographic , clinical , and gait data at baseline . there were no significant differences between groups for clinical data at posttest . the purposed multimodal exercise program has found improvement in some kinematic gait parameters for the tg . further study in the form of randomized controlled trial would be required to establish effectiveness of the intervention .

electroweak measurements by the cdf and dzero collaborations on the tevatron at fermilab center around @xmath0 and @xmath1 boson production in proton - antiproton collisions . only the leptonic decays of the bosons are considered since these channels have relatively small backgrounds . the well known @xmath0 and @xmath1 boson production cross sections are high , and when they are combined with the clean decay signatures , precision electroweak measurements are attainable . precision measurements of the @xmath0 and @xmath1 boson cross sections times branching ratios in the leptonic decay channels not only test the standard model description of the production process , but they can also be used to test lepton universality by comparison of the different channels . the ratio of the @xmath0 and @xmath1 production cross sections is used as an indirect measurement of the @xmath0 boson mass and width . with sufficiently precise measurements of @xmath0 boson production , the transverse mass distribution can be used as a direct measurement of the mass and width of the @xmath0 boson and the charge asymmetry of the produced @xmath0 bosons constrains the proton parton distribution functions . in @xmath1 boson production , the forward backward asymmetry yields a measurement of @xmath2 and the @xmath1-quark couplings , and searches for higher mass @xmath3 bosons are conducted . finally , measurements of diboson production processes ( _ i.e. _ @xmath4 , @xmath5 , @xmath6 and @xmath7 production ) are used to study triple and quartic gauge couplings . production of @xmath0 and @xmath1 bosons is an important background to studies of the top quark and searches for the higgs boson and susy particles , where detailed understanding of the backgrounds is important . the upgrades to the cdf and dzero detectors for run ii , combined with of luminosity delivered by the tevatron by summer 2004 , with instantaneous luminosties above @xmath8@xmath9s and rising , give the collaborations the ability to conduct electroweak measurements at higher precision than ever before available at a hadron collider . the results presented here represent the status of electroweak analyses at cdf and dzero as of june 2004 and use up to 200 pb@xmath10 of the initial luminosity delivered by the tevatron . decays of the @xmath1 boson are identified by observing two high @xmath11 leptons with an inviariant mass near the @xmath1 boson mass . decays of @xmath0 bosons are distinguished by one high @xmath11 lepton and missing transverse energy from the escaping neutrino . since the longitudinal momentum of the neutrino can not be unambiguously determined , the lepton - neutrino invariant mass can not be calculated . however , since the transverse momentum of the neutrino is estimated using the missing transverse energy , the transverse mass , @xmath12 } $ ] , can be calculated and is expected to be high . the electronic and muonic decay channels primarily used for these analyses offer the cleanest signatures . electronic decays are triggered by a deposition of energy in the electromagnetic layers of the calorimeter . final electron identification requires the deposition of energy to be consistent with an electromagnetic shower and generally requires a track to be matched to the energy cluster in the calorimeter . muonic triggers require a muon to be found in the muon chambers and a track with high @xmath11 to be seen in the inner tracker . muons used in analyses are required to have an isolated high @xmath11 track matched either to a muon detector track or to the track of a muon as a minimum ionizing particle passing through the calorimeter . the efficiencies of the triggers and object identification are measured using @xmath13 events where one lepton has passed all the identification and trigger requirements , leaving the other lepton as an unbiased probe for studying efficiencies . the primary backgrounds to @xmath0 and @xmath1 boson production come from qcd jets and the background contributions are estimated using jet data . the cross section times branching ratio for @xmath14 is measured by both experiments using electrons with greater than 25 gev of transverse energy . dzero uses electrons with no track match required and @xmath15 and the invariant mass of the electron pair is required to be between 60 and 110 gev . the measurement by cdf counts events in a mass window between 65 and 115 gev and requires tracks to be matched to both electrons , with one electron required to be central while the other electron is allowed to be forward . there are small backgrounds from jets faking electrons and from @xmath1 boson decays to @xmath16 where the taus decay electronically . dzero uses 41 pb@xmath10 of luminosity while cdf uses 71 pb@xmath10 , yielding 1139 and 4242 events respectively . the cross section times branching ratio calculated by cdf is @xmath17 pb . the measurement reported by dzero includes a small correction for the contribution from drell - yan production and is found to be @xmath18 pb . for the @xmath19 cross section times branching ratio measurement , cdf uses muons above 20 gev with @xmath20 1.0 while dzero uses muons above 15 gev with @xmath20 1.8 . this channel has very small backgrounds from qcd b - quark jets that decay semi - leptonically to muons , cosmic muons , and @xmath21 decays where the taus decay muonically . cdf uses 72 pb@xmath10 of data and finds 1371 events in a 65 to 115 gev invariant mass window , while dzero uses 117 pb@xmath10 of data and finds a total of 6126 events . the cdf measurement of the cross sesction times branching ratio is @xmath22 pb and the dzero result is @xmath23 pb . these cross sections are in good agreement with the measurements of @xmath1 boson production in the electron channel . measurements of the @xmath0 boson production cross sections are also made in the electron and muon decay channels . for the measurement in the electron channel , both cdf and dzero look for an electron with above 25 gev of transverse energy in events with above 25 gev of missing transverse energy . in 42 pb@xmath10 of data , dzero requires the electron to be central and selects @xmath2427,400 events , while cdf uses central and forward electrons in two separate analyses that use 72 pb@xmath10 of data and finds a total of @xmath2448,000 events . the main background comes from jet events with a jet faking an electron and mismeasurement leading to missing transverse energy . secondary backgrounds come from @xmath25 decays where the tau decays electronically and from @xmath14 decays where one electron is missed . dzero measures a cross section times branching ratio of @xmath26 . using central electrons , cdf measures @xmath27 and using forward electrons finds @xmath28 . measurements for the cross section times branching ratio for @xmath29 use events with missing transverse energy greater than 20 gev and muons having @xmath30 . dzero uses muons with @xmath31 while cdf uses muons with @xmath32 . the dzero analysis uses the initial 17 pb@xmath10 of tevatron luminosity and observes @xmath248,300 events while the cdf result uses 72 pb@xmath10 of luminosity and finds @xmath2431,700 events . the resulting cross sections times branching ratio are @xmath33 from dzero and @xmath34 for cdf . as with the measurements for @xmath1 boson production , the measurements for @xmath0 boson production in the electron and muon channels are in good agreement . the efficiencies and purities attained by cdf and dzero are similar except where cdf includes forward electrons and where dzero uses forward muons . these differences will soon be resolved as cdf will include farther forward muons and dzero will include forward electrons . a summary of the run ii cross sections is shown in figure [ wzxsecs ] along with the cross sections measured in run i and nlo predictions by van neerven and matsuura . both the run i and run ii measurements are in agreement with the theoretical predictions . by using the measured ratio of @xmath0 and @xmath1 boson cross sections times branching ratios and theoretical inputs , an indirect measurement of the @xmath0 boson branching ratio to leptons and the full @xmath0 boson width can be made using the relation @xmath35 the values of @xmath36 and @xmath37 , the total @xmath0 and @xmath1 boson production cross sections , are obtained from an nnlo calculation by van neerven , the @xmath1 boson branching ratio @xmath38 is taken from lep measurements and the partial @xmath0 boson width is a standard model electroweak calculation . following this procedure after combining the cdf electron and muon channels yields @xmath39 , @xmath40 and @xmath41 gev , which are in agreement with the world average values . as a check of lepton universality , the @xmath0 and @xmath1 boson cross sections are measured in the tau decay channels . both cdf and dzero measure the cross section times branching ratio for @xmath21 using events where one tau decays leptonically and the other tau follows a one - prong hadronic decay . dzero looks for the leptonic decay of a tau in the muon channel in 68 pb@xmath10 of data and finds a cross section times branching ratio of @xmath42 pb . the measurement by cdf uses electronic decays of the tau and a luminosity of 72 pb@xmath10 and the result is @xmath43 pb . these measurements are in agreement with the cross sections measured in the other lepton channels and demonstrate the ability to observe resonances in di - tau final states . cdf has also measured the cross section times branching ratio for @xmath25 production . the analysis uses events triggered by events with a central track and missing transverse energy . reconstruction of the tau decay is accomplished by finding an energy cluster in the calorimeter with tracks matched to it within a 10@xmath44 cone and no tracks between the 10@xmath44 cone and a 30@xmath44 cone . individual @xmath45 particles from the tau decay are reconstructed using detectors in the calorimeter at shower max , and the combined invariant mass of the cluster is required to be less than the mass of the tau . after accounting for backgrounds from @xmath29 , @xmath46 , @xmath47 , and jets , a cross section times branching ratio of @xmath48 nb is measured . assuming a consistent @xmath0 boson production cross section , this measurement implies that the ratio of the coupling of the @xmath0 boson to the tau to the coupling to the electron is @xmath49 . higher precision measurements are possible with improvements in a number of areas . the largest error in many measurements is the luminosity error which is as large as 10% in some cases . the understanding of the luminosity measurement is improving , and cdf and dzero now use identical luminosity determinations , which have an improved error of 6.5% . with the record luminosities provided by the tevatron , large data sets are becoming available . collection and analysis of additional data will not only improve the statistical errors but will also lead to smaller systematics from lepton identification as well as refined estimates of background contributions . improvements in the understanding of detector response and material descriptions will also increase the precision of the measurements . understanding of the proton parton density functions and the associated systematic errors is improving with use of the recently available full error treatments in the cteq6 and mrst parton density function sets . combining the results from cdf and dzero with full accounting for correlated errors will yield the most precise measurements . to that end , the tevatron electroweak working group has been formed and has produced early combined tevatron results @xcite . measurements of various angular asymmetries in @xmath0 and @xmath1 boson production are sensitive to details of electroweak physics as well as the parton distribution functions of the proton . in the process @xmath50 , the asymmetry @xmath51 where theta is the polar angle between the incoming proton and the outgoing lepton , is sensititive to the v - a coupling to the @xmath1 boson . measurements of @xmath52 and the @xmath53 and @xmath54 quark couplings can be made by fitting to the shape of this asymmetry as a function of center of mass energy . this analysis has been performed by cdf using electronic decays of the @xmath1 boson and finds @xmath55 is @xmath56 and quark couplings consistent with the standard model values . since up - type quarks carry more average momentum than down - type quarks , @xmath57 bosons tend to be boosted in the proton direction while @xmath58 bosons tend to be boosted in the antiproton direction . thus , a measurement of the charge asymmetry @xmath59 can be used to constrain the parton distribution functions of the proton , particularly for the @xmath53 and @xmath54 quarks at high @xmath60 . since the neutrino in @xmath46 decays escapes the detector unobserved , the direction of the produced @xmath0 boson can not be unambiguously determined . however , the direction of the outgoing electron / positron is correlated , with increasing correlation with increasing transverse energy , to the @xmath0 boson s direction . so , the asymmetry is measured using the rapidity of the electron / positron . the @xmath0 charge asymmetry has been measured by the cdf collaboration using @xmath0 boson events where the transverse mass is between 50 and 100 gev and no other electromagnetic object with @xmath61 gev is allowed . the charge of the track matched to the electromagnetic calorimeter is used to determine whether the outgoing particle was an electron or a positron . forward silicon detectors are used with calorimeter seeded tracking to determine the charge up to @xmath62 , and the charge misidentification rate determined from @xmath14 events is @xmath63 for the central region and @xmath64 farther forward . backgrounds bias the asymmetry toward zero and are subtracted using monte carlo techiniques for @xmath14 and @xmath25 backgrounds and using the data for jet backgrounds . figure [ wasym ] shows the resulting measurement as well as the uncertainty range obtained from the cteq6 error parton distribution functions . as expected , the largest sensitivity in this measurement is for forward electrons / positrons with high transverse energy . as this measurement is refined , strong constraints will improve the uncertainties of the parton distribution functions . for @xmath46 as measured by cdf . the set of curves represents the uncertainty in cteq6 using the 40 error parton distribution functions.__,width=264 ] the invariant mass spectrum of dilepton pairs in @xmath50 is described well by theoretical predictions at low mass where statistics are high . deviations from the predictions would indicate new physics , and many postulated processes are searched for at high invariant mass . for example , both dzero and cdf have searched for a @xmath3 boson . no excesses are observed and dzero sets a 95% confidence level limit on the mass of a @xmath3 boson with standard model couplings to be greater than 780 gev . a 95% confidence level limit of 735 gev is set by the cdf analysis . limits on other new physics are also set using the drell - yan invariant mass spectrum and are reported on elsewhere in these proceedings @xcite . collisions at the tevatron can produce multiple bosons . these events can be used to probe the gauge structure of electroweak physics and search for anomalous couplings . diboson production is an important background in searches for new physics and improved modeling of diboson production will aid in those searches . as in measurements of @xmath0 and @xmath1 single boson production , dzero and cdf focus on the electronic and muonic decays of the bosons in order to minimize backgrounds . in @xmath65 production the photon can come from initial state radiation from one of the incoming quarks , final state radiation from an outgoing lepton , or radiation directly from the @xmath0 boson . this final source of photons is dependent on the @xmath66 triple gauge coupling and destructively interferes with the initial state radiation contribution . if this coupling is different than that in the standard model , an excess of photons at high transverse energy is expected . both cdf and dzero measure @xmath65 production in the electron and muon channels by first selecting @xmath67 events and adding a photon requirement . photons are identified as isolated electromagnetic showers in the central calorimeter with no track matched to them and having separation @xmath68 from the outgoing lepton to reduce the influence of final state radiation . photons in the cdf analysis are required to have @xmath69 gev while dzero requires @xmath70 gev . the primary background is from @xmath0+jet events where the jet leaves an electromagnetic deposit in the calorimeter and fakes a photon . smaller backgrounds come from @xmath71 and @xmath1+jet events where one lepton from the @xmath1 boson decay is lost , @xmath72 where the tau decays leptonically and any process which can produce a lepton and an electron in the final state which fakes a photon . the dzero analysis combines the electron and muon channels and uses 162 pb@xmath10 of data for the electron channel and 82 pb@xmath10 for the muon channel . a total of 146 events is found in the electron channel with an estimated background of @xmath73 events , while 77 events are found in the muon channel with an expected background of @xmath74 events . this leads to a cross section times branching ratio of @xmath75 pb that compares well with the baur nlo calculation of @xmath76 pb for @xmath65 production with photon @xmath70 gev . the cdf analysis finds 259 events after combining electron and muon channels in 202 pb@xmath10 of data . the estimated background is @xmath77 events and the cross section times branching ratio is @xmath78 pb . the baur nlo prediction for the cross section with photon @xmath69 gev is @xmath79 pb and is in good agreement with the cdf measurement . neither experiment observes an excess of high @xmath80 photons and both of the experiments are in the process of setting limits on anomalous couplings . similar analyses have been pursued for @xmath81 production . while the same initial and final state radiation contributions exist in @xmath81 production as in @xmath65 production , the standard model forbids radiation of a photon directly from a @xmath1 boson , and no triple gauge coupling contribution is expected . thus , the triple gauge coupling contribution destructively interferes in @xmath65 production but not in @xmath81 production , and the relative background contribution from @xmath1+jet production is smaller than the relative contribution of @xmath0+jet production to @xmath65 events . cdf has measured @xmath81 production for central photons with @xmath82 7 gev that satisfy @xmath83 in both the electronic and muonic @xmath1 boson decay channels in 202 pb@xmath10 pb of data . a total of 69 events is observed with an estimated background of @xmath84 events . this yields a cross section of @xmath85 pb which compares well with the baur nlo calculation of @xmath86 pb . again , no excess of high energy photons is observed , and limits on anomalous couplings are forthcoming . pairs of @xmath0 bosons can also be produced in tevatron collisions and constitute an important background to some higgs searches where the higgs is expected to decay to @xmath0 boson pairs . analyses searching for h@xmath87 are discussed elsewhere in these proceedings @xcite . backgrounds to @xmath4 production include drell - yan , other diboson production , @xmath21 where the taus decay leptonically , and top quark pair production . two analyses from cdf measure production of @xmath0 boson pairs . the first analysis is a high purity analysis that uses events with two high @xmath80 leptons with opposite charge , missing transverse energy greater than 25 gev and no high energy jets . events in this analysis are rejected if the dilepton mass is near the @xmath1 boson mass and the missing transverse energy significance is low . a second , higher efficiency analysis requires events to have one high transverse energy lepton and one isolated high transverse momentum track . both analyses use 184 pb@xmath10 of data , and the high purity analysis finds 17 events with an expected background of @xmath88 events . this results in a cross section measurement of @xmath89 pb . the high efficiency analysis finds 39 events with a background of @xmath90 events and a cross section of @xmath91 pb . both of these cross sections are in agreement with the nlo calculation by ellis and campbell , which predicts @xmath92 pb . finally , the production of @xmath93 and @xmath5 boson pairs is searched for at cdf by looking for two to four leptons in electron and muon channels . the analysis uses 194 pb@xmath10 and requires one lepton pair to be consistent with the mass of the @xmath1 boson . four events are observed with a background estimated to be @xmath94 events , and the production cross section of @xmath93 or @xmath5 is determined to be less than 13.8 pb at the 95% confidence level . a standard model calculation by ellis and campbell predicts the cross section to be 5.2 pb . a large number of precision measurements of various parts of electroweak physics has been reported by experiments at lep , slc and the tevatron . at the @xmath1-pole , measurements of the @xmath1 lineshape , polarized leptonic asymmetries , heavy flavor asymmetries , heavy flavor branching fractions and hadronic charge asymmetry have been conducted by experiments at lep and slc . additionally , the mass of the @xmath0 boson has been measured by experiments using the lep-2 collider and the tevatron , and the top quark mass has been measured at the tevatron . in the standard model , each of these observables can be calculated in terms of other electroweak parameters . the mass of the higgs and the top quark enter as radiative corrections of order 1% . programs such as zfitter and topaz0 are used @xcite to fit to the observables and make predictions for variables such as the mass of the higgs . important contributions to the uncertainty of the predicted mass of the higgs come from the uncertainties on the masses of the @xmath0 boson and top quark . run ii of the tevatron provides a unique environment to measure both masses to precisions not before attainable . measurements of the @xmath0 boson s mass at lep-2 are accomplished by fully reconstructing @xmath95 or @xmath96 events . the difference in the mass measured in the two different final states is @xmath97 mev and the mass measured by combining results from all lep experiments is @xmath98 gev . the measurements at the tevatron rely on fits to the tail of the transverse mass spectrum . using data from run i of the tevatron , combining the dzero and cdf results gives a measured mass of @xmath99 gev . significant contributions to uncertainties uncorrelated between the cdf and dzero experiments arise from the number of @xmath0 bosons collected , the lepton energy scale and modeling of the hadronic recoil . the increased luminosity available in run ii along with upgrades to the detectors will reduce these uncertainties . additionally , the uncertainties in the proton s parton distribution functions lead to significant errors correlated between the experiments . these uncertainties are expected to be reduced as information from the @xmath0 boson charge asymmetry and @xmath1 boson rapidity distribution is used to constrain the parton distribution functions . each experiment expects to achieve a precision of @xmath100 gev on the measurement of the mass of the @xmath0 boson . combining the results from the two detectors should result in an uncertainty of @xmath240.025 gev and would improve the current world average measurement of @xmath101 gev . the mass of the top quark was measured in run i and a recent update by dzero @xcite has resulted in @xmath102 smaller errors on that measurement . the details of the analysis are discussed elsewhere in these proceedings @xcite and result in a measurement of the top quark mass of @xmath103 gev . inclusion of this update in the combined tevatron average gives a top quark mass of @xmath104 gev , which represents an increase of 3.7 gev from the previous tevatron average . a preliminary measurement of the top quark mass in run ii has been completed by cdf and is reported elsewhere in these proceedings @xcite but is not yet included in the electroweak fits . the expected accuracy of the measurement of the top quark mass in run ii is 2.5 gev . comparing the values for the masses of the @xmath0 boson and top quark obtained by the electroweak fits to direct measurements is a test of the performance of the standard model . the top quark mass predicted by the fit is @xmath105 gev , which is in good agreement with the tevatron measurement . the predicted value for the mass of the @xmath0 boson of @xmath106 is also in good agreement with the direct measurements ; however , the error on the direct measurement is larger than the error of the prediction . the precision of the run ii measurements of the @xmath0 boson s mass is expected to be similar to the error of the prediction . fitting to the lep , slc and tevatron data is also used to predict the mass of the higgs . the resulting most likely mass of the higgs particle is @xmath107 gev with a 95% confidence level upper limit of 237 gev . improving the precision of the measurement of the top quark mass with the inclusion of run ii data can be clearly seen to be important because the relatively small increase of 3.7 gev in the measured top quark mass results in an increase of nearly 20 gev in the most likely value for the mass of the higgs particle . a large number of electroweak measurements by cdf and dzero using tevatron run ii data has been presented , and the measurements are in agreement with the standard model . detector understanding is increasing , as are the sizes of the data sets available . these increases in precision are leading to preliminary @xmath0 boson mass measurements with a combined tevatron goal of 25 mev accuracy . the @xmath0 boson mass measurements along with improving top quark mass measurements are important elements of electroweak fits which predict the higgs mass . using the most recent updates to the run i top quark mass measurement , the higgs mass is constrained to be less than 237 gev at the 95% confidence level . i would like to thank the organizers of pic 2004 an interesting and informative series of lectures . i would also like to thank my colleagues from dzero , cdf and the lep electroweak working group for their help in the preparation of this presentation . 99 the tevatron electroweak working group , http://tevewwg.fnal.gov/. e. nagy , these proceedings . the lep electroweak working group , http://lepewwg.web.cern.ch/. a.m. abazov _ at al _ , an improved measurement of the top quark mass , nature * 429 * , 638 ( 2004 ) . a. hocker , these proceedings .

electroweak measurements from early in run ii of the tevatron collider at fermilab are presented as well as future prospects for run ii . the effect of tevatron measurements on worldwide electroweak fits and the higgs mass is also discussed . = 14.5pt

among the nearly 2000 exoplanets discovered so far , more than half are transiting systems . due to the rotation of the host star , the observed stellar radial velocity ( rv ) is expected to change as the planet transits different parts of the rotating stellar surface . this is called the rossiter - mclaughlin ( rm ) effect and was initially measured for eclipsing binary stars @xcite . after the first observation of the exoplanetary rm effect by @xcite , there are now more than 80 exoplanet systems with this effect observed , e. g. @xcite . this effect is normally used to measure the projected angle between the stellar spin and the planetary orbit . @xcite was the first to propose using the wavelength - dependent rm effect to probe the atmospheres of transiting exoplanets . this method exploits the fact that the planetary effective radius is wavelength - dependent due to differential atmospheric absorptions . @xcite theoretically modeled the rm effect for the na absorption of giant exoplanets . the advantage of the rm method compared to the traditional spectrophotometry is that it does not demand the use of photometric reference stars . the rm method promises to become a powerful technique for future transmission spectrum measurements , especially as the next generation of very large ground - based telescopes are likely to have a small field - of - view , making it difficult to employ suitable reference stars . with more and more terrestrial exoplanets being discovered , the characterization of their atmospheres will become a major goal for exoplanet research in which the rm method can play an important role . although it is currently difficult to observe the rm effect of these terrestrial exoplanets due to instrumental limitations , a lunar eclipse provides us with an opportunity to observe the earth transiting the sun and so explore the effectiveness of the rm method . the concept of regarding the earth as an exo - earth using lunar eclipses has been applied in the past by @xcite . these studies obtained the transmission spectrum directly from the ratio spectrum before and during a lunar eclipse . here we present for the first time the use of the rm effect of an earth transit during a lunar eclipse to retrieve the transmission spectrum . we observed the 15-april-2014 lunar eclipse with the high accuracy radial velocity planet searcher ( harps ) mounted on the eso la silla 3.6 m telescope @xcite . a consecutive sequence of observations over one entire night covered all of the eclipse stages , i.e. the penumbral and umbral eclipse and out of eclipse ( called hereafter the bright moon ) . the classical fiber spectroscopy mode was used with the fiber located at the center of the tycho crater ( see fig . [ nasa - tycho ] for the trajectory ) . the telescope used non - sidereal tracking and the tracking velocities were updated every few minutes . in addition , manual guiding on crater structures was performed . this worked reasonably well and limited the pointing coordinate drift to @xmath0 1.5 arcmin . we used varying exposure times during the eclipse because the lunar surface brightness changed dramatically . in total , 382 lunar spectra were obtained ( table [ observation ] ) . [ cols="^,^,^,^,^",options="header " , ] data reduction was performed using the harps pipeline . each exposure frame comprises 72 spectral orders that cover the wavelength range from 378 nm to 691 nm with a spectral resolution of @xmath1 @xmath2 115,000 . radial velocities are measured , for each spectral order as well as for the overall spectral range , using a cross - correlation with a g2 stellar spectral template . the overall measured and theoretical rv curves are shown in fig . [ rme - curve ] . the theoretical rv is the combination of two components : the motion of the sun with respect to tycho and the motion of tycho with respect to the observer . these velocities are calculated with the jpl horizon ephemeris , which considers the orbital motions , rotations of the earth and the moon , and the light travel time corrections . there is an offset between the theoretical rv and the measured rv , which probably originates from the rv zero - point of the spectral template used by the harps pipeline @xcite . we correct this offset by using the data points taken during the bright moon as a baseline . [ rme - curve ] shows the measured rv with the motion rv corrected and the baseline offset subtracted . this is the final rv curve of the rm effect for the earth transiting the sun . at the bright moon stage , the rv is essentially corrected to zero , but there is still a small slope with an amplitude of about 4 m / s which is probably due to the instrumental drift and the non - perfect telescope guiding when observing the moon . since the rm amplitude is on the order of 2 km / s , this small residual slope does not significantly affect our analysis . when the moon enters the 1st penumbra , the observed rv becomes negative ( blueshift ) as the earth begins to transit the redshifted rotating part of the solar disk . at the umbral stage , the rv gradually changes from a blueshift to a redshift . when the moon enters the 2nd penumbral stage , the rv is redshifted since the earth obscures mainly the blueshifted solar region . the rv gradually decreases during this stage as the moon moves out of the penumbral shadow . the umbral rv has a relatively complex structure and its details are determined by a combination of both the refracted part of the solar disk and the properties of the earth s atmosphere refracting the sunlight . in this work , the umbral part is not studied since we focus only on the penumbral parts for the rm effect . to retrieve the wavelength - dependent rm effect due to the earth s atmospheric absorption , we firstly establish an rm model to take into account the wavelength - dependent solar parameters . our model follows the method described in @xcite and @xcite . we divide the solar disk into elements with a size of @xmath3 and the radial velocity due to solar rotation for each element is : @xmath4 where @xmath5 is the rotation angular velocity , @xmath6 is the inclination of the solar spin axis towards tycho , x and y are in the sky - plane coordinate system of which the origin is at the projected solar center and the y - axis is along the projected solar rotation axis . the coordinate values are in units of the solar radius @xmath7 . the rv anomaly @xmath8 due to the rm effect is then calculated by integrating the intensity - weighted rvs of the visible solar disk : @xmath9 the rm curve for white - light ( i.e. the entire wavelength range of the harps spectrum ) is generated from this model ( the black line in fig . [ white - light - model ] ) . the parameters are further described as follows : 1 . the coordinates of the earth s center and the solar center as seen from tycho are generated using the horizon ephemeris . we use the earth radius of @xmath10 km and the solar radius of @xmath11 km . these data are used to determine the visible part of the solar disk at a given time . the inclination @xmath6 is calculated using the solar north pole position angle given by horizon . the mean value of @xmath6 is @xmath12 and changes by about @xmath13 during the eclipse . the solar differential rotation used is @xcite : @xmath14 where @xmath15 is the heliographic latitude and is calculated with : @xmath16 the coefficients adopted are a = 13.46 , b = -2.99 @xcite . the quadratic limb - darkening coefficients @xcite are used for the white - light model to calculate the intensity @xmath17 . we adopt the coefficients used by @xcite , i.e. @xmath18 and @xmath19 . for an exoplanet transit , the projected angle between the stellar spin and the planetary orbit is calculated by fitting the observed rv with the rm model . however , we adopt the actual data from the horizon ephemeris and so the model curve in fig . [ white - light - model ] is not the result of such a fit . the projected spin - orbit " angle for this observation is @xmath20 calculated using the trajectory of the earth as seen from tycho . because this trajectory is the combination of the earth and lunar orbits , the angle is not the real spin - orbit angle of the sun - earth system of @xmath21 . the stellar convective motion results in a blueshift of the lines which is called the convective blueshift ( cb ) @xcite . as the cb radial component varies across the stellar disk , the observed stellar rv changes when a planet transits the stellar surface . @xcite discusses the cb during an exoplanet transit and its effect on the rm effect . we follow the cb model in @xcite and adopt a typical cb value of the sun @xmath22 m / s for the white - light rv calculation . the blueshift value for each element on the solar disk is @xmath23 , where @xmath24 . the rv change caused by cb ( blue line in fig . [ white - light - model ] ) is then calculated in a similar way to the rm model and added to the rv value caused by the rm effect to give the red line in fig . [ white - light - model ] . the effects of atmospheric refraction are important for interpreting the transits of terrestrial planets @xcite and affect the rm effect . as the atmosphere refracts the light from the stellar disk region that should be obscured by the planet , the apparent effective radius of the planet will appear smaller than without refraction . thus in general , refraction would result in a smaller rm amplitude than without refraction . in our rm model , we do not include atmospheric refraction , which means the modelled rm amplitude should be larger than the actual observed rm amplitude . this is consistent with the result in fig . [ white - light - model ] in which the modelled rv value without refraction ( red line ) is generally larger than the observed rv ( green points ) . in the rm model described above , we assume the line profile is dominated by the stellar rotation and use the first - moment approximation @xcite . this assumption gives us the rv anomaly expressed by equation [ equ - deltarv ] . however , other mechanisms like the microturbulence , macroturbulence and instrumental broadening also affect the line profile and can change the shape of the rv curve @xcite . this may contribute to the discrepancy between the modelled rv and the observed rv in fig . [ white - light - model ] . the harps pipeline produces directly a rv value for each of the 72 spectral orders . three orders do not have useful rv data due to the lack of stellar lines in the corresponding spectral mask . after correcting for the earth - moon - sun motion and the baseline offset described in section 2 , we obtain 69 rm curves each representing a different wavelength range . to obtain the rm effect differences caused by the earth s atmosphere , the wavelength - dependent solar parameters need to be considered . the first aspect concerns the stellar convection blueshift . the actual rv caused by cb depends on where the line forms , e.g. the strong lines or low - excitation lines may have a small cb because they usually form high in the stellar atmosphere where the granulation is weak @xcite . as each of the harps spectral orders comprises stellar lines with different cb values , the @xmath25 of each spectral order varies . therefore , unlike the white - light cb model for which we can assume @xmath22 m / s , the actual cb effect for a given harps order is difficult to model . instead , we use two symmetric parts on the rv curve to cancel this effect utilizing the fact that the convection induced rv anomaly during transit is symmetric with respect to the mid - transit as shown by the blue line in fig . [ white - light - model ] . two regions of the rm curve ( labelled as pm1 and pm2 in fig . [ white - light - model ] ) are then chosen . the pm1 and pm2 are symmetric regions of the eclipse , i.e. they are at the same distance from mid - eclipse . [ rme - amplitude]a shows the rv values of pm1 and pm2 and the rv difference between them ( i.e. pm2 - pm1 ) . we use this pm2 - pm1 value to represent the rm effect amplitude for each spectral order . from fig . [ rme - amplitude]a , it can be seen that there is a correlated systematic difference between pm1 and pm2 . we believe that this correlated pattern results from the measured effect of the cb depending on the type and number of spectral lines present in each spectral order but is well - cancelled by using pm2 - pm1 . the second wavelength - dependent solar parameter is the limb - darkening . here we use the empirical power - law limb - darkening coefficients from @xcite . for each of the harps orders , we interpolate a limb - darkening coefficient at the corresponding wavelength and calculate a value of pm2 - pm1 with a fixed earth radius ( 6378 km ) using our rm model . the model values of pm2 - pm1 are shown in fig . [ rme - amplitude]b . the final rm effect at different wavelength ranges , after the correction of the limb - darkening , is presented in fig . [ rme - amplitude]c . the limb - darkening correction made here is mainly for the continuum , however , since the solar lines have different limb - darkening compared to the adjacent continuum @xcite , this could introduce some extra noise in the final rm amplitudes . the rv curve of the wavelength - dependent rm amplitudes in fig.[rme - amplitude]c results from the different effective radius at different wavelengths , and it can be regarded as a mapping of the low resolution transmission spectrum of the earth s atmosphere into effective radius and hence radial velocity space . to interpret the observed atmospheric features , we build a transmission spectral model following the methods of @xcite and @xcite . we calculate the overall transmission spectrum of the earth atmosphere from 0 to 80 km altitude considering the ozone absorption and rayleigh scattering extinction ( blue line in fig . [ rme - amplitude]c ) . this transmission spectrum is overlaid with the rm amplitude curve to compare their shapes . we emphasize here that the transmission spectrum model is not used to fit the observed rm amplitude curve but to demonstrate the presence of the atmospheric features mapped into it . by comparing the spectral shapes in fig . [ rme - amplitude]c , we interpret the rm amplitude curve as follows : the rm amplitude is larger towards the blue due to rayleigh scattering extinction that makes the atmosphere more opaque and the atmospheric effective thickness larger at shorter wavelengths . the broad peak around 600 nm results from the ozone chappuis band absorption while the rm amplitude towards the red becomes smaller since both the ozone absorption and the rayleigh scattering become weaker , rendering the atmosphere more transparent . the rm model we have used for this work suffers from several defects and incompleteness . the first is observational in that there is a slight , but barely significant , drift in the telescope guiding on the lunar surface . the second is that other line broadening mechanisms like the stellar micro / macro - turbulence are not included in the rm model ( cf . subsection [ sec - turbulence ] ) . the third is more fundamental and its full solution is beyond the scope of this letter . this is the determination of the detailed mapping between the rm amplitude and the atmospheric exctinction as a function of wavelength . this depends on the effects of atmospheric refraction in the exoplanetary atmosphere which will be influenced not only by the absorption coefficients of its gaseous constituents but also by the effects of screening due to clouds and aerosols . the combination of these effects can explain the slight deviation of the modelled rv from the observed rv values . it can also explain why the modelled rm amplitudes for the limb darkening correction are larger than the observed rm amplitudes ( shown in fig . [ rme - amplitude]b ) . however , this has a very limited effect on our retrieval of the final rm amplitude curve since the limb - darkening correction produces only a small rv variation with wavelength so that the shape of the final rm amplitude curve is little affected by the rm model . future modelling work containing a proper treatment of refraction and stellar turbulence will allow us to combine the transmission spectral model with the rm model , and to fit the observed rm amplitude curve directly instead of just comparing its shape with the transmission spectrum as presented in the current work . we have observed for the first time the rossiter - mclaughlin effect of the earth transiting the sun using a lunar eclipse . the rm effect curve has been obtained using high accuracy rv observations and an rm effect model is built to analyze the observed result . separate rm curves at different wavelengths are obtained from 69 harps spectral orders . after the correction of the wavelength - dependent limb - darkening of the sun and the convective blue - shift of the solar lines , we retrieve the wavelength - dependent rm amplitudes due to the transmission of the earth s atmosphere . the ozone chappuis band and the rayleigh scattering signatures are clearly detectable . the rm method can be used to detect broad features , such as the rayleigh scattering , in exoplanet atmospheres . the advantage is that no reference stars are needed in contrast to the requirements for the traditional spectrophotometric method . since the next - generation ground - based telescopes such as e - elt will have a relatively small field - of - view , limiting the access to nearby reference stars , the rm method will provide a promising technique for the characterization of planetary atmospheres . thus , in the future , this method can be applied to detect the atmospheres of terrestrial planets and particularly to search for the bio - signature gas ozone . extending the observation to near - infrared ( nir ) wavelengths will yield more absorption features . however , the ability of the rm method is limited by the number of suitable spectral lines of the parent star . the sun , for example , does not have sufficient lines in the nir . however , for m - type stars which are expected to be promising targets for exoplanet atmosphere studies , there are many stellar molecular lines in the nir which can be exploited . we greatly appreciate the excellent support from the lasilla / paranal science operations team . in particular , we thank valentin ivanov for performing the observations on site and his and lorenzo monaco s support during the preparation of the observing run . we would also like to thank gaspare lo curto and andrea chiavassa for helpful discussions and the referee for useful suggestions . the study is supported by the national natural science foundation of china under grants nos . 11390371 and 11233004 . _ facilities : _ .

due to stellar rotation , the observed radial velocity of a star varies during the transit of a planet across its surface , a phenomenon known as the rossiter - mclaughlin ( rm ) effect . the amplitude of the rm effect is related to the radius of the planet which , because of differential absorption in the planetary atmosphere , depends on wavelength . therefore , the wavelength - dependent rm effect can be used to probe the planetary atmosphere . we measure for the first time the rm effect of the earth transiting the sun using a lunar eclipse observed with the eso harps spectrograph . we analyze the observed rm effect at different wavelengths to obtain the transmission spectrum of the earth s atmosphere after the correction of the solar limb - darkening and the convective blueshift . the ozone chappuis band absorption as well as the rayleigh scattering features are clearly detectable with this technique . our observation demonstrates that the rm effect can be an effective technique for exoplanet atmosphere characterization . its particular asset is that photometric reference stars are not required , circumventing the principal challenge for transmission spectroscopy studies of exoplanet atmospheres using large ground - based telescopes .

filament ( prominence ) eruption is one of the most spectacular , large - scale activity on the sun , which often associates with solar flare and coronal mass ejection ( cme ) . the eruption of a filament can severely impact the solar - terrestrial environment and human activities ; and the study of these phenomena has developed into a new discipline dubbed space weather . however , the physical mechanism of filament eruption is still not well understood , even though extensive observational and theoretical works have been made in recent decades . generally speaking , a filament eruption always starts from a closed magnetic system in quasi - static equilibrium , in which the upward magnetic pressure force of the low - lying sheared field is balanced by the downward tension force of the overlying field . when the eruption begins , the equilibrium is destroyed catastrophically , and part of the non - potential magnetic flux and the plasma are expelled violently from the sun . given different magnetic environments , the eruption of a filament can be failed , partial , and complete eruptions ( e.g. , @xcite ) . sometimes , several filaments far from each other or resided in one complex active region can erupt successively within a short time period . a key question of successive eruptions is whether they are physically connected or not . it seems that the answer is positive , and the connection is often of a magnetic nature ( e.g. , @xcite ) . currently , solar physicists have developed a number of models for interpreting filament / cme eruptions . among various models , the magnetic breakout model assumes a large - scale quadrupolar field configuration ; the core field is increasingly sheared by photospheric motions , which is surrounded by an overlying antiparallel loop system ( @xcite ) . naturally , a null point is formed between the core and the overlying loop system . this model can be used to interpret many eruptions which occur in complex multipolar active regions ( e.g. , @xcite ) . here , we apply the magnetic breakout model to explain successive filament eruptions which occurred in a quadrupolar magnetic source region , and propose a possible physical linkage between the filament eruptions . the basic magnetic topology of the breakout model is shown in figure.[fig1 ] . it can be seen that the four magnetic poles ( p1 , n1 , p2 , and n2 ) are connected by three low - lying lobes and one overlying loop system ; and a coronal null resides inbetween the middle lobe and the overlying antiparallel loop system . in addition , one can assume the existence of a filament under each lobe ( f1 , f2 , and f3 ) . in such a configuration , a small disturbance to the system could lead to the eruption of the whole system . typically , there are two types of disturbance to the system . the first type is that the disturbance acts on f2 , which will lead to the rising of f2 and the middle lobe , and further results in the external reconnection around the null point , which will removes the confining field of f2 to the lateral lobes and thereby reduce ( increase ) the confining capacity of the middle ( lateral ) lobe . therefore , this type of disturbance often lead to failed eruptions of f1 and f3 , while the eruption of f2 should be a successful one . the second type is that the disturbance acts on f1 or f2 , which will not lead to any reconnection , and therefore no filament eruption occurs . here , we present another type of filament eruption in a solar breakout event , in which successive partial and full filament eruptions are involved . the detailed analysis of the event can be found in @xcite . here we just give a brief summery of the results . as shown in fig.[fig2](a ) , we find that the extrapolated coronal field above the magnetic source region is of the topology of the breakout model , and the two filaments are located below the middle and the left lobes respectively . the initiation of the successive filament eruptions started from a small mass ejection , which directly interacted with the southern part of f2 and thus resulted in the slow rise of this filament . the slow rise of f2 lasted for about 23 minutes and a speed of 8 km / s . during this period , some signatures for breakout - like external reconnection were observed . for example , two brightening patches at both sides of f1 , the appearance of bright loops and a weak hard x - ray source above f1 . after the slow rising phase , f2 was quickly accelerated to 102 km / s , and finally , it erupted successfully and caused a cme . the activation of f1 started around the end of f2 s slow rising phase , which erupted with strong writhing motions . when f1 reached its maximum height , the eruption of a blob - like structure was observed above the filament . in the meantime , f1 began to fall back to the solar surface . these results indicate that the eruption of f1 should be a typical partial flux rope eruption . according to the model proposed by @xcite , the reconnection site should be located above the filament . we interpret the observations using the breakout model as shown in fig.[fig2 ] . panel ( a ) presents basic magnetic topology . due to the disturbance introduced by a small plasma ejection , f2 slowly rises , expanding the middle lobe , which will result in the external magnetic reconnection within the current sheet formed around the coronal null point ( see cs1 in panel ( b ) ) . according to the magnetic implosion mechanism proposed by @xcite , the magnetic pressure around the reconnection site will decrease due to energy released during the energy conversion process in coronal transients such as flares . the reduction of magnetic pressure will lead to the contraction of the overlying loop system and the expansion of the low - lying lobes . in addition , the strong writhing of f1 indicates that the eruption of this filament was driven by the kink instability . the reduction of the magnetic tension force of the left lobe facilitates triggering the kink instability within f1 . hence , the magnetic implosion could be a possible physical linkage between the successive filament eruptions within the framework of the breakout model . as the rising of f1 and f2 , new current sheet cs2 ( cs3 ) will form underneath ( above ) f2 ( f1 ) . the reconnection within cs2 ( cs3 ) will lead to the successful ( partial ) eruption of f2 ( f1 ) , and the cme ( blob ) ( see panels ( c ) and ( d ) ) . in this model , we can expect two simultaneous cmes . based on multi - wavelengths observations , we propose an interpretation for the successive eruptions of two filaments in a solar breakout event . we first introduce the magnetic implosion mechanism to be the physical linkage of the successive filament eruptions . the observations of both the pre - eruptive signatures and the extrapolated three - dimensional coronal fields are in good agreement with the breakout model . our scenario presented in this article implies the occurrence of nearly simultaneous cmes . therefore , this interpretation is important for the forecast of space weather . it should be noted that the breakout scenario is a possible explanation for the observations . we do not intend to exclude other possibilities . in any case , the structural properties of coronal fields are important for producing successive filament eruptions . + * acknowledgements * this work is supported by the western light youth project of chinese academy of sciences ( cas ) , the cas open research programs ( klsa201204 , dms2012kt008 ) . y. shen thank the financial support for young researches to participate the 300th symposium ( iaus300 : nature of prominences and their role in space weather ) of the international astronomical union . antiochos , s. k. 1998 , _ apj _ , 502 , l181 antiochos , s. k. , devore , c. r. , & klimchuk , j. a. 1999 , _ apj _ , 510 , 485 aulanier , g. , deluca , e. e. , antiochos , k. s. , mcmullen , r. a. & golub , l. 2000 , _ apj _ , 540 , 1126 gilbert , h. r. , holzer , t. e. , low , b. c. , & burkepile , j. t. 2001 , _ apj _ , 549 , 1221 hudson , h. s. 2000 , _ apj _ , 531 , l75 jiang , y. , shen , y. , yi , b. , yang , j. , & wang , j. 2008 , _ apj _ , 677 , 699 jiang , y. , yang , j. , hong , j. , bi , y. , & zheng , r. , 2011 , _ apj _ , 738 , 179 liu , y. , su , j. , xu , z. , lin , h. , shibata , k. et al . 2009 , _ apj _ , 696 , l70 lynch , b. j. , & edmondson , j. k. 2013 , _ apj _ , 764 , 87 maia , d. , aulanier , g. , wang , s. j. , et al . 2003 , _ a&a _ , 405 , 313 plunkett , s. p. , vourlidas , a. , @xmath0imberov@xmath1 , s. et al . 2000 , _ sol . _ , 194 , 371 schrijver , c. j. , title , a. m. , yeates , a. r. , & derosa , m. l. 2013 , _ apj _ , 773 , 93 schrijver , c. j. , & title , a. m. 2011 , _ j_. geophys . res . , 116 , a04108 shen , y. , liu , y. , & liu , r. 2011 , _ res . _ , 11 , 594 2012 , _ apj _ , 750 , 12 titov , v. s. , mikic , z. , t@xmath2k , t. , linker , j. a. , panasenco . o. 2012 , _ apj _ , 759 , 70 t@xmath2k , t. , panasenco , o. , titov , v. s. , et al . 2011 , _ apj _ , 739 , l63

the magnetic breakout model has been widely used to explain solar eruptive activities . here , we apply it to explain successive filament eruptions occurred in a quadrupolar magnetic source region . based on the high temporal and spatial resolution , multi - wavelengths observations taken by the atmospheric imaging assembly ( aia ) on board the _ solar dynamic observatory _ ( _ sdo _ ) , we find some signatures that support the occurrence of breakout - like external reconnection just before the start of the successive filament eruptions . furthermore , the extrapolated three - dimensional coronal field also reveals that the magnetic topology above the quadrupolar source region resembles that of the breakout model . we propose a possible mechanism within the framework of the breakout model to interpret the successive filament eruptions , in which the so - called magnetic implosion mechanism is firstly introduced to be the physical linkage of successive filament eruptions . we conclude that the structural properties of coronal fields are important for producing successive filament eruptions .

the interaction of solitons has been a subject of great interest right from the beginning of their early investigations @xcite . new fundamental features of soliton interactions are still being discovered , in fact the existence of a phase - dependent spatial jump in the trajectories of two colliding matter - wave solitons , reported in a recent experiment @xcite , is just one example to be mentioned . apart from its scientific importance soliton interactions have also a practical importance . for instance , interaction between optical solitons sets the limit on the rate of information transfer in fiber optic communication systems @xcite . due to important applications , soliton interactions are extensively studied , both theoretically and experimentally , in optical fibers @xcite , photonic crystals @xcite and plasmas @xcite . recent experimental studies have shown that in addition to interactions between neighboring optical solitons in close proximity , there exists also a long range interaction between them @xcite . the generation of spatially separated coherent matter - wave packets and their subsequent interaction constitute the basic phenomena in the operation of modern atomic interferometers @xcite working in the solitonic regime @xcite where the fringe visibility is significantly increased compared with an ordinary atomic cloud , as demonstrated in @xcite . solitons have been experimentally observed in many areas of physics , including the bose - einstein condensates ( bec ) @xcite . the experiments with solitons in bec reported so far were concerned with the creation of solitons and studying their collective dynamics . regarding the type of interaction between matter - wave solitons a conjecture was made from the behavior of neighboring solitons in a soliton train @xcite . meanwhile , it would be interesting to explore systematically the interaction between two matter - wave solitons with varying spatial separation and relative phase . recent progress in controlled creation and manipulation of matter - wave solitons in bec @xcite indicates that such experiments on soliton interactions are now within the scope of current technology . a key role belongs to a minimally destructive polarization phase - contrast imaging technique @xcite , that allows to make multiple imaging of the soliton pair during a single experimental run , as reported recently with regard to phase - dependent collision of two matter - wave solitons @xcite . an essentially new method reported in ref . @xcite for controlled ( i.e. deterministic in both soliton position and momentum ) creation of matter - wave bright solitons and soliton pairs without the use of feschbach resonances opens new perspectives for investigation of soliton interactions in bec with unprecedented accuracy . experimental realization of chromium bec with long range dipole - dipole atomic interactions @xcite has opened new direction in the physics of ultra - cold quantum gases . subsequently two other species with strong dipolar interactions , namely dysprosium @xcite and erbium @xcite , were bose - condensed . the principal difference of chromium condensates from the alkali atom condensates is that , @xmath2cr has a large permanent magnetic dipole moment @xmath3 , where @xmath4 is the bohr magneton . since the dipole - dipole force is proportional to the square of the magnetic moment , the dipolar interactions in chromium condensate is a factor of 36 times stronger than in alkali atom condensates , like @xmath5rb ( @xmath6 ) . similar arguments pertain also for other dipolar quantum gases , @xmath7dy ( @xmath8 ) and @xmath9er ( @xmath10 ) . in this work we study , by means of variational approximation ( va ) and numerical simulations , the interaction between two bright solitons in a dipolar bec . we employ a strategy similar to that used in the experimental investigation of the interaction forces between fiber optic solitons @xcite . following that idea in numerical experiments we create two bright solitons at some initial spatial separation , then give the pair a chance to evolve for some period of time , and finally measure the distance between the solitons when the evolution time has elapsed . depending on whether the distance between the solitons has increased , decreased or remained unchanged , compared to its initial value , we conclude about the type of soliton interaction as being repulsive , attractive or neutral , respectively . there is a qualitative difference between solitons in dipolar and non - dipolar media . specifically , two anti - phase solitons in dipolar media attract each - other at large separation and repel at short separation . due to this property they can form stable bound states with non - zero binding energy , whereas in non - dipolar media they always repel and never form stable bound state . the possibility of molecular type of interaction between solitons in dipolar bec moving in two neighboring wave - guides was shown in @xcite . the existence of stable multi - soliton structures in 2d dipolar bec was also reported in @xcite . our main objective in this work is to find the conditions when two interacting solitons in the same quasi-1d waveguide form a stable bound state , which can be considered as a basic matter - wave soliton molecule . when a stable bound state of two solitons has been realized , we characterize the soliton molecule by its bond length and binding energy . our work distinguishes itself from other relevant publications in that , we use the va with a gauss - hermite ansatz and analytically tractable function of non - locality ( response function ) , which allows to describe essential features of soliton molecules in dipolar bec . moreover , we provide detailed comparison of predictions of va with the results of numerical simulations of the gross - pitaevskii equation . the paper is organized as follows . in the next section ii we introduce the governing equation and develop the va for the dynamics of soliton molecules in dipolar bec . in sec . iii we use an optimization procedure to find the shape of a soliton molecule and validate the va by comparing the analytical predictions with the results of numerical simulations . in sec . iv we present such an important characteristic of a soliton molecule as its binding energy . in sec . v we reveal the character of soliton interactions in dipolar bec using the method borrowed from the field of fiber optic solitons . in sec . vi we summarize our findings . from the viewpoint of theoretical description , matter - wave solitons in bec and optical solitons in fibers are similar . the mean field gross - pitaevskii equation ( gpe ) for the dynamics of bec and the nonlinear schrdinger equation for propagation of optical solitons in fibers have formal analogy . similarity of the basic equations has been fruitful in transferring many ideas from nonlinear optics to the field of matter - waves @xcite . in this paper we transfer one more idea , concerning soliton interactions , from the field of fiber optics into the field of bec . we shall consider the one dimensional gpe by taking into account both the local and nonlocal nonlinearities , which account for the usual contact interactions between atoms , and the long - range dipole - dipole interactions @xcite @xmath11 where @xmath12 is the coefficient of contact interactions , controlled by the atomic @xmath13-wave scattering length @xmath14 , with @xmath15 being its background value , @xmath16 is the coefficient of nonlinearity , responsible for the long - range dipolar atomic interactions , expressed via characteristic dipole length @xmath17 , with @xmath18 being the mass and magnetic dipole moment of atoms , oriented along the @xmath19 axis , @xmath20 is the permeability of vacuum . time and space are expressed in units of @xmath21 and @xmath22 , respectively , with @xmath23 being the frequency of radial confinement . the wave function is re - scaled as @xmath24 and normalized to the reduced number of atoms in the condensate @xmath25 , which is a conserved quantity of eq . ( [ gpe ] ) . the following two models for the kernel ( nonlocal response functions ) are relevant to dipolar condensates confined to quasi-1d traps @xmath26 the former kernel was derived for the dipolar bec using the single mode approximation @xcite , while the latter containing a cutoff parameter @xmath27 , was proposed in ref . @xcite and is more convenient for analytical treatment . making use of the matching conditions @xmath28 which requires @xmath29 , one can take advantage of the simplicity of @xmath30 for the application of va . the meaning of @xmath31 is the effective size of the dipole . actually , it takes value of the order of the transverse confinement length , which makes the model one - dimensional , and sets the unit length in eq . ( [ gpe ] ) . therefore , the choice of @xmath32 is quite reasonable . in the limit @xmath33 , where dipole - dipole interaction effects dominate the contact interaction effects , both response functions behave as @xmath34 . this justifies application of the kernel function @xmath35 for analytical treatment of dipolar effects in bec . by comparing the graphics of these two response functions one can be convinced , that indeed @xmath36 and @xmath35 match very closely @xcite . the lagrangian density generating the eq . ( [ gpe ] ) is @xmath37,\ ] ] where @xmath38 , @xmath39 , @xmath40 and @xmath41 are variational parameters , associated with the amplitude , width , chirp and phase , respectively . the norm @xmath42 is proportional to the number of atoms in the condensate . for specified values of @xmath43 and @xmath44 , the waveform ( [ ansatz2 ] ) can be well approximated by two anti - phase gaussian functions with the amplitude @xmath45 , width @xmath46 and half separation @xmath47 @xmath48 substitution of the ansatz ( [ ansatz2 ] ) and response function ( [ r2 ] ) into the lagrangian density ( [ lagden1 ] ) and subsequent integration over the space variable @xmath19 yields the averaged lagrangian @xmath49,\ ] ] where @xmath50 is the confluent hypergeometric function @xcite , and @xmath51 . the va equation for the parameter @xmath44 of the two - soliton molecule , which is proportional to the separation between solitons , can be derived from the euler - lagrange equations @xmath52 for variational parameters @xmath53 , using the averaged lagrangian ( [ lagr ] ) @xmath54.\ ] ] the corresponding effective potential @xmath55 for the width is depicted in fig . [ fig1 ] ( left panel ) . the analytic form of the potential @xmath55 , which can be found by integrating the right hand side of eq . ( [ attmol ] ) , is rather complicated and we do not show it here explicitly . the fixed point @xmath56 of this equation @xmath46 is associated with the stationary separation between center - of - mass positions of two solitons constituting the molecule @xmath57 . at larger separation ( @xmath58 ) the solitons attract each other ( @xmath59 ) , and at smaller separation ( @xmath60 ) they repel ( @xmath61 ) , therefore the effective potential @xmath55 has a property of molecular type . [ fig1 ] ( right panel ) illustrates the shape of a two - soliton molecule , as predicted by va , by two anti - phase gaussian functions with parameters given in eq . ( [ aax ] ) , and by optimization procedure , applied to gpe ( [ gpe ] ) , described in the next subsection . ) for different strengths of the contact interaction . right panel : the shape of a two - soliton molecule in a pure dipolar bec with @xmath62 , @xmath63 , @xmath64 as predicted by va with trial function ( [ ansatz2 ] ) for @xmath65 , @xmath66 , @xmath67 ( red solid line ) , by two anti - phase gaussian functions with parameters given in eq . ( [ aax ] ) ( blue dashed line ) , and found from numerical optimization procedure , applied to gpe ( [ gpe ] ) ( brown dash - dot line ) . the minimum of the effective potential @xmath55 is attained at @xmath68 , and the equilibrium distance between center - of - mass positions of pulses predicted by eq . ( [ aax ] ) is @xmath69 , while the gpe optimization gives @xmath70.,title="fig:",width=302,height=226 ] ) for different strengths of the contact interaction . right panel : the shape of a two - soliton molecule in a pure dipolar bec with @xmath62 , @xmath63 , @xmath64 as predicted by va with trial function ( [ ansatz2 ] ) for @xmath65 , @xmath66 , @xmath67 ( red solid line ) , by two anti - phase gaussian functions with parameters given in eq . ( [ aax ] ) ( blue dashed line ) , and found from numerical optimization procedure , applied to gpe ( [ gpe ] ) ( brown dash - dot line ) . the minimum of the effective potential @xmath55 is attained at @xmath68 , and the equilibrium distance between center - of - mass positions of pulses predicted by eq . ( [ aax ] ) is @xmath69 , while the gpe optimization gives @xmath70.,title="fig:",width=302,height=226 ] when solitons of the molecule are placed at their equilibrium positions , they stay motionless , as shown fig . if solitons are slightly displaced and released , they perform small amplitude oscillations around their stationary separation . the dynamics of the molecule strongly depends on the initial phase difference between solitons . in particular , even slight deviation from anti - phase configuration leads to periodic exchange of atoms between solitons . at larger deviation the soliton molecule does not form . ) gaussian pulses with parameters @xmath71 , @xmath72 , placed at their equilibrium positions @xmath73 . ( b ) when the solitons are slightly ( by 20 % ) displaced from equilibrium positions , they perform oscillations . density plot @xmath74 is obtained by numerical solution of the gpe ( [ gpe ] ) . dashed line corresponds to calculations according to va equation ( [ attmol ] ) , which shows increasing phase shift with respect to gpe . ( c ) periodic exchange of atoms between two solitons when the initial phase difference is slightly decreased.,title="fig:",width=207,height=226 ] ) gaussian pulses with parameters @xmath71 , @xmath72 , placed at their equilibrium positions @xmath73 . ( b ) when the solitons are slightly ( by 20 % ) displaced from equilibrium positions , they perform oscillations . density plot @xmath74 is obtained by numerical solution of the gpe ( [ gpe ] ) . dashed line corresponds to calculations according to va equation ( [ attmol ] ) , which shows increasing phase shift with respect to gpe . ( c ) periodic exchange of atoms between two solitons when the initial phase difference is slightly decreased.,title="fig:",width=207,height=226 ] ) gaussian pulses with parameters @xmath71 , @xmath72 , placed at their equilibrium positions @xmath73 . ( b ) when the solitons are slightly ( by 20 % ) displaced from equilibrium positions , they perform oscillations . density plot @xmath74 is obtained by numerical solution of the gpe ( [ gpe ] ) . dashed line corresponds to calculations according to va equation ( [ attmol ] ) , which shows increasing phase shift with respect to gpe . ( c ) periodic exchange of atoms between two solitons when the initial phase difference is slightly decreased.,title="fig:",width=207,height=226 ] the frequency of soliton oscillations near equilibrium state can be estimated from linearized version of eq . ( [ attmol ] ) @xmath75.\end{aligned}\ ] ] for the period of oscillations near the stationary separation we have @xmath76 . the prediction of va is in qualitative agreement with the result of numerical simulation of the gpe , @xmath77 ( see fig . [ fig2 ] ) . in general , the va provides fairly good description of the static and dynamic properties of the soliton molecule , while its waveform remains close to the selected trial function ( [ ansatz2 ] ) . the agreement between va and gpe deteriorates at large separation between solitons , close to the dissociation point , when the trial function can not be well approximated by two anti - phase gaussian functions . the va provides approximate waveform of a soliton molecule . when a trial function with parameters , defined by stationary solution of va equation , is assigned as initial condition for the gpe , small amplitude oscillations of the molecule s shape and separation between pulses is observed . this implies that soliton molecule is in its excited state . for some precise parameter calculations , such as the binding energy of soliton molecules , a truly ground state should be employed . in ref . @xcite an optimization strategy to find the stationary shape of a soliton molecule in dispersion - managed optical fibers was proposed . below we extend this approach for soliton molecules in dipolar bec . it is based on the nelder - mead ( nm ) nonlinear optimization procedure @xcite , which seeks to minimize an objective ( or cost ) function @xmath78 where @xmath79-\exp\left[-\frac{(x+x_0)^2}{2a_0 ^ 2}\right]\right)\ ] ] is the initial waveform , composed of two anti - phase gaussian functions , separated by a distance @xmath80 , and @xmath81 is the result of evolution of @xmath82 for some period of time @xmath83 , according to gpe . normalization factor @xmath84 in eq . ( [ cost ] ) is introduced to avoid trivial solutions , in particular corresponding to @xmath85 . in general case minimization of the objective function can be performed with respect to variables @xmath46 and @xmath47 , since the amplitude @xmath45 is fixed by the norm of the gaussian . however , numerical experiments show that , va predicted values of @xmath46 and @xmath45 for a single soliton are quite accurate , and minimization only with respect to pulse separation @xmath47 can produce stationary state of the molecule . the evolution time @xmath86 can be estimated as half period of oscillation for the molecule @xmath87 . although the nm optimization procedure finds the minimum of the objective function ( [ cost ] ) for gaussian functions with broad range of parameters , the convergence rate can be improved by selecting the initial waveform close to the stationary state . the va can provide the waveform which is close to the stationary state . we find stationary pulse separation @xmath47 and norm of the soliton molecule @xmath88 from nm optimization procedure . the obtained results were confirmed by alternative method of luus - jaakola @xcite . our preference of these optimization methods is motivated by several advantages , such as simplicity of programming ( since calculation of function derivatives is not required ) , high convergence rate and reliability and effectiveness in locating the global minimum of the objective function . the binding energy of a soliton molecule @xmath89 can be defined as the amount of energy , which is required for the dissociation of the molecule into two separate individual free solitons , far away from each other . in numerical simulations using the gpe , the process of dissociation can be implemented by assigning an initial velocity to each soliton in opposite directions @xmath90 . if the velocity is smaller than some critical value @xmath91 , solitons perform oscillations around their stationary positions , otherwise the molecule disintegrates into individual solitons , travelling in opposite directions , as illustrated in fig . [ fig3 ] . , solitons perform oscillations near equilibrium positions . at critical velocity the molecule dissociates into freely moving individual solitons ( red solid lines ) . , width=302,height=226 ] in a particle in potential well " picture this situation corresponds to the escape of the particle from the potential well at critical kinetic energy . the critical velocity determines the binding energy of the molecule @xmath92 . [ fig4 ] illustrates the potential of interactions between the two solitons , normalized to binding energy , as a function of distance between solitons in units of stationary separation @xmath47 . to construct the potential @xmath93 we assign velocity to solitons and determine the maximal and minimal value of the separation , which correspond to right and left classical turning points of the oscillating particle in the potential well . repeating these calculations for velocities in the range @xmath94 $ ] we construct the potential , shown in the left panel of fig . as expected , the bigger norm @xmath88 ( or number of atoms ) of the molecule corresponds to stronger potential , connecting solitons . in fig . [ fig1 ] is evident . right panel : the stationary half separation between solitons of the molecule @xmath47 ( blue dashed line ) and its binding energy @xmath89 ( red solid line ) as a function of the molecule s norm @xmath88 . symbols correspond to values found from numerical simulations of the gpe ( [ gpe ] ) , and lines are interpolating curves for visual convenience . , title="fig:",width=302,height=226 ] in fig . [ fig1 ] is evident . right panel : the stationary half separation between solitons of the molecule @xmath47 ( blue dashed line ) and its binding energy @xmath89 ( red solid line ) as a function of the molecule s norm @xmath88 . symbols correspond to values found from numerical simulations of the gpe ( [ gpe ] ) , and lines are interpolating curves for visual convenience . , title="fig:",width=302,height=226 ] the critical velocity @xmath95 , at which the molecule disintegrates into far separated individual solitons , is determined from gpe simulations , by setting in motion the two bound solitons in opposite directions , as shown in fig . [ fig4 ] . in the experiment pushing the solitons in opposite directions can be realized by means of a laser beam , directed into the center of the molecule , as it was used to split the condensate in two halves @xcite . the intensity of the laser beam can be varied to give desired initial velocity to solitons . about the repulsive interaction between two anti - phase solitons the following comment is appropriate . as experimentally demonstrated in @xcite and theoretically shown in @xcite , two colliding wave packets exchange not only velocities ( as classical particles do ) , but also their entire wave - functions ( as quantum mechanical particles do via tunnel phenomenon ) . in our case of equal masses of two colliding solitons , the classical and quantum descriptions lead to the same result . physically , the repulsive interaction of anti - phase matter wave solitons can be regarded as exchange of velocities of two colliding classical particles interacting via hard core potential . in order to study the character of interaction between two matter - wave solitons in numerical experiments we employ the idea similar to that used for optical solitons in fibers @xcite . initially at @xmath96 , two solitons either in - phase @xmath97 or out - of - phase @xmath98 , are created at some distance @xmath99 from each - other . at later time @xmath100 the distance between solitons is measured again . if the solitons did not interact , the distance between them should not change with respect to its initial value @xmath101 . if the interaction was attractive , the final measured distance should be less than the initial distance @xmath102 . finally if the interaction was repulsive , the final distance should be greater than the initial distance @xmath103 . the numerical experiment consists in repeating the above procedure for different values of the initial distance @xmath99 , starting from sufficiently large separation , greatly exceeding the width of the soliton then reaching small distances when solitons start to overlap . the result is presented in fig . [ fig5 ] as a plot of @xmath104 ( final separation ) vs. @xmath99 ( initial separation ) . when the solitons , comprising the molecule , are out of phase ( @xmath98 ) we see that at large separations the solitons do not interact ( @xmath105 , red curve is close to median ) , while at small distances they attract each other ( @xmath102 , red curve is below the median ) until they reach a minimum ( stationary ) separation , where again @xmath101 ( red dot on the median ) . when solitons are placed at even smaller distances , they repel each other ( @xmath103 , red curve is above the median ) . that is , the two - soliton molecule behaves like a diatomic molecule . for in - phase solitons ( @xmath106 ) we see that solitons attract each other until their separation becomes comparable to the width of the soliton , then merge forming a wave packet , whose shape strongly oscillates . . right panel : in - phase solitons always collide and do not form stable bound state.,title="fig:",width=226,height=226 ] . right panel : in - phase solitons always collide and do not form stable bound state.,title="fig:",width=226,height=226 ] . right panel : in - phase solitons always collide and do not form stable bound state.,title="fig:",width=226,height=226 ] the numerical simulations are performed using realistic values of atom numbers and interaction parameters in @xmath7dy for which @xmath107 kg , @xmath108 a m@xmath109 , @xmath110 m. the frequency of radial confinement @xmath111 hz provides radial oscillator length @xmath112 m and unit of time @xmath113 ms . for parameter values @xmath114 and @xmath62 used in numerical simulations we obtain the number of atoms in a two - soliton molecule @xmath115 . the total number of atoms in the @xmath7dy condensate was @xmath116 @xcite . we have studied the interaction between two bright solitons in a dipolar bec and found the conditions when they form a stable bound state . it was revealed by numerical simulations of the governing nonlocal gpe and corresponding variational analysis , that two anti - phase solitons in dipolar condensates behave similarly to a diatomic molecule . namely , they attract each - other at large separation and repel each - other at small separation . there exists a particular distance at which the two solitons remain motionless in their stationary state . solitons in a weakly perturbed molecule perform small amplitude oscillations near the equilibrium position , the frequency of which is predicted quite accurately by the developed model . two in - phase solitons when placed close to each - other always collide and do not form the bound state . the obtained results can be useful in further studies of the properties of multi - soliton bound states in dipolar bec . this work has been supported by king fahd university of petroleum and minerals under research group projects rg1333 - 1 and rg1333 - 2 . bbb thanks the department of physics at kfupm and sctp for the hospitality during his visit . a. d. cronin , j. schmiedmayer , and d. e. pritchard , rev . phys . * 81 * , 1051 ( 2009 ) ; t. berrada , s. van frank , r. bcker , t. schumm , j. -f . schaff , and j. schmiedmayer , nature commun . 4 , 2077 ( 2013 ) . j. cuevas , p. g. kevrekidis , b. a. malomed , p. dyke and r. g. hulet , new j. phys . * 15 * , 063006 ( 2013 ) ; j. polo and v. ahufinger , phys . rev . a * 88 * , 053628 ( 2013 ) ; h. michinel , a. paredes , m. m. valado , and d. feijoo , phys . rev . a * 86 * , 013620 ( 2012 ) . s. burger et al . , phys . rev . lett . * 83 * , 5198 ( 1999 ) ; j. denschlag et al . , science * 287 * , 97 ( 2000 ) ; k. e. strecker et al . , nature * 417 * , 150 ( 2002 ) ; l. khaykovich et al . , science * 296 * , 1290 ( 2002 ) ; s. l. cornish et al . , lett . * 96 * , 170401 ( 2006 ) ; c. becker et al . , nat . phys . * 4 * , 496 ( 2008 ) ; c. hamner et al . , phys . * 106 * , 065302 ( 2011 ) . m. stratmann , t. pagel , and f. mitschke , phys . * 95 * , 143902 ( 2005 ) ; p. rohrmann , a. hause , and f. mitschke , sci . rep . * 2 * , 866 ( 2012 ) ; p. rohrmann , a. hause , and f. mitschke , phys . rev . a * 87 * , 043834 ( 2013 ) ; a. hause and f. mitschke , phys . a * 88 * , 063843 ( 2013 ) . c. pare and p .- a . belanger , opt . 168 , 103 ( 1999 ) ; b .- f . feng and b. a. malomed , opt . 229 , 173 ( 2004 ) ; s. m. alamoudi , u. al khawaja , and b. b. baizakov , phys . rev . a * 89 * , 053817 ( 2014 ) .

the interaction between two bright solitons in a dipolar bose - einstein condensate ( bec ) has been investigated aiming at finding the regimes when they form a stable bound state , known as soliton molecule . to study soliton interactions in bec we employed a method similar to that used in experimental investigation of the interaction between solitons in optical fibers . the idea consists in creating two solitons at some spatial separation from each other at initial time @xmath0 , and then measuring the distance between them at a later time @xmath1 . depending on whether the distance between solitons has increased , decreased or remained unchanged , compared to its initial value at @xmath0 , we conclude that soliton interaction was repulsive , attractive or neutral , respectively . we propose an experimentally viable method for estimating the binding energy of a soliton molecule , based on its dissociation at critical soliton velocity . our theoretical analysis is based on the variational approach , which appears to be quite accurate in describing the properties of soliton molecules in dipolar bec , as reflected in good agreement between the analytical and numerical results .

metallic structures are commonly used in space technology . they build skeletons of spacecrafts , they protect satellites interiors from rapid temperature changes ( mli blankets ) , or they are used as highly reflecting mirrors of optical space telescopes . nowadays , metals are also used as thin layers on polyimide - type foils which have a broad usage in the solar sail technology . a failure of a space mission may be the result of a change of metallic structure properties caused by the environmental effects . therefore , all of the materials planned for space applications have to be evaluated for their behavior under particle and electromagnetic radiation @xcite . it is known from many of these evaluation tests that particle and electromagnetic radiation can significantly degrade materials ( see e.g. * ? ? ? * ; * ? ? ? * ; * ? ? ? many kinds of metals have found their application in space industry , e.g. aluminum , copper , nickel , titanium , steels , and others @xcite . for instance aluminum is one of the basic building materials of existing spacecrafts and is component of many subsystems . copper is used in electrical , electronic and in general engineering applications . nickel has its application e.g. in heating elements . titanium is chosen in space applications for its mechanical- , temperature - properties , and chemical resistance @xcite . however , it is very clearly stated that the radiation at the level existing in space does not modify the properties of metals @xcite . the here presented paper proves that the thin metallic foils are especially sensitive to the ion irradiation . the free electrons within the metals can in a well defined energy range recombine with the solar wind protons into neutral hydrogen atoms . recombination processes and their consequences have direct effects onto the foils physical and thermo - optical properties @xcite . the result of a recombination of metal free electrons and solar protons is a formation of bubbles filled with hydrogen molecular gas ( see e.g. * ? ? ? * ; * ? ? ? bubble formation is one of the four degradation mechanisms caused by hydrogen ( referred to as embrittlement ) : formation of a hydride phase , enhanced local plasticity , grain boundary weakening and bubble formation @xcite . when @xmath0-bubbles are formed on irradiated metallic surfaces , their reflectivity decreases with increasing surface density of the bubbles @xcite . a reflectivity is a key parameter for many thin metallic foil applications e.g. in the solar - sail propulsion technology . since the reflectivity is directly proportional to the momentum transfer from solar photons to the sail s material , its decrease will reduce the propulsion performance of a sail - craft just linearly proportional to the reduction of the reflectivity @xcite . the future solar sail missions will be realized in the interplanetary medium ( see e.g. * ? ? ? * ; * ? ? ? * ; * ? ? ? unfortunately , the real degradation behavior of metallic samples is to a great extent unknown . hence , detailed studies , both theoretical and experimental , are performed at german aerospace center ( dlr ) in bremen , germany with a cooperation of university of zielona gra , poland . the here presented thermodynamic model simulates the growth of @xmath0-bubbles . the model input parameters are : the energy and flux of solar protons , type , and the temperature of the irradiated metal . the diffusivity of h in the metal lattice was taken into account , as well as back scattering effect ( bs ) of the solar protons irradiating the target . the model output is the velocity of bubble radius growth , the maximum possible bubble radius , and , for a given bubble density and average bubble radius , the reduction factor of the reflectivity with respect to its ideal value . the paper is organized as follows . in section [ recombination ] , the typical proton flux spectra at the distance of @xmath5 au from the sun are presented . the value of the proton flux can be transformed to any distance orbit from the sun , see eq . [ flux_r ] . four recombination processes of the metal free electrons and the incident protons are presented : auger - , resonant- , oppenheimer - brinkman - kramers ( obk ) , and radiative electron capture ( rec ) - process . in section [ models ] general principles and conditions for the @xmath0-bubble formation are given . next , the thermodynamic model of bubble formation is introduced . also a simple model of specular reflectivity reduction due to growing population of bubbles is presented . in section [ results ] experimental results as well as validation of the thermodynamic model are presented . the reflectivity of metallic surfaces which are populated by a given surface density of bubbles is studied as well . finally , in section [ conclusions ] , the conclusions are drawn . devices , while operating in the interplanetary space , are exposed to solar wind and electromagnetic radiation . the solar wind , as the sun s corona , is essentially made up of electrons and protons plus a small proportion of heavier ions , and it carries a magnetic field . particles and fields are intimately coupled in plasmas ( * ? ? ? * ch.1 ) . extraterrestrial sun observatories measure a few key solar wind parameters , e.g. : components of proton and electron velocity , their mean number density as well as components of the magnetic field . fig . [ p_flux ] shows solar proton at 1 au distance from the sun for its average activity . proton fluxes are calculated by use of the data collected by the soho ( since 1995 ) and the ace ( since 1997 ) satellites . the omere database is also considered . when a probe is irradiated in space , it collects incident ions from a wide energy range . the range depends on the type and the thickness of an irradiated material . the thiner the target material , the less ions stuck in it . therefore , there must exist a critical energy of incident ions ( @xmath6 ) above which they pass through the material . hence , the integrated proton flux over the energies is : @xmath7 where @xmath8 is the ion s lowest energy recorded by the satellite s detector system . the @xmath9 values are presented in the table [ integrated_proton_flux ] . to calculate the fluxes the ace database was used . obviously , the @xmath6 depends on materials type and thickness . the @xmath10 @xmath4 m @xmath11 foil covered on both sides with @xmath12 nm al layer has been used to perform the first proton irradiation tests at dlr . for that coating thickness all of the protons with energy lower than @xmath13 kev will stuck in the aluminum layer . therefore , the integrated proton flux is @xmath14 [ @xmath15@xmath2@xmath16 . .integrated proton fluxes over the energies for @xmath17 au distance orbit from the sun . [ cols="^,^",options="header " , ] [ integrated_proton_flux ] to estimate the flux of solar protons @xmath18 at distance @xmath19 from the sun , the following relation can be used : @xmath20 incident protons , while penetrating the metallic target , recombine with its free electrons to neutral hydrogen atoms . there are four recombination processes of ions into neutral atoms : 1 . auger process + in the auger processes , an electron is captured by the incident ion to a bound state ( here a proton ) forming neutral hydrogen . in order to conserve energy an auger - electron or photon is released ( see e.g. * ? ? ? * ; * ? ? ? * ; * ? ? ? * ; * ? ? ? * ; * ? ? ? * ; * ? ? ? * ; * ? ? ? resonant process + the resonant recombination proceeds when the incident ion is neutralized by an electron which is tunneled to a metastable state @xcite . the inverse process is also possible . an electron which is in a metastable state with respect to the metallic ion can populate one of the free electron states of the metal only if it becomes free ( the pauli exclusion principle ) . + the effect comes from the crystal structure itself . the resonant processes are due to the potential seen by the moving ion i.e. they are described in a frame where the incident ion is at rest @xcite . from the point of view of the ion , there appear a moving periodic potential which gives rise to transitions between bound states of the ion - electron pair ( composite ) and free electron states @xcite . oppenheimer - brinkman - kramers ( obk ) process , + the obk process is a capture process , where an inner or outer shell electron of a target atom is transferred to the moving ion @xcite . in the literature there are many physical approaches ( see e.g. * ? ? ? * ; * ? ? ? * ; * ? ? ? * ; * ? ? ? * ; * ? ? ? * ; * ? ? ? * ; * ? ? ? * ; * ? ? ? * ; * ? ? ? * ; * ? ? ? * ; * ? ? ? * ; * ? ? ? different results may be obtained depending on the approximation applied to the wave functions and the energy levels involved in the process @xcite . + in the obk process the outer - shell electrons of metal ions experience a strong coulomb field of the incident ion . the wave function of the electrons is distorted @xcite . for the inner - shell capture , the screening effect of the outer - shell electrons of the metallic ions reduces the capture probability of an electron by the incident particle @xcite . radiative electron capture ( rec ) process . + in the rec process an electron is transferred from the target atom to the incident ion with the simultaneous emission of a photon , see @xcite or ( * ? ? ? 10 , p. 151 ) . it occurs at ion energies exceeding @xmath21 mev ( for aluminum as target material ) @xcite . since the solar wind consists mainly of low ( @xmath22 kev ) energetic protons , only the first three processes are responsible for recombination . the efficiency of the recombination processes is determined by their cross sections @xmath23 . the cross section of each recombination process is calculated by use of the concept of so - called _ transition amplitude _ @xmath24 . it determines the probability , @xmath25 , for a transition from an eigenstate @xmath26 to @xmath27 ( * ? ? ? 15 , p. 227 ) . here @xmath28 stands for probability of a recombination event i.e. that an electron is bound to an incident ion . @xmath29 is the complex conjugate of a , @xmath26 is an eigenstate of the incident ion and an electron before recombination takes place , while @xmath27 is an eigenstate of the ion - electron composite . hence , the cross section of recombination event can be written as : @xmath30 where @xmath31 is the impact parameter . fig . [ summary ] shows the different cross sections for capture processes when aluminum is irradiated with protons ( @xmath32 ) as a function of proton kinetic energy given in kev @xcite . one can see that the auger process @xmath33 is the dominant one . the resonant process @xmath34 has negligible contribution to the total cross section . the obk process @xmath35 ( in the literature it is often called the shell process ) gives the main contribution to the total cross section at some mev , depending on the target material @xcite . ion : auger ( @xmath33 ) , resonant ( @xmath34 ) and obk ( @xmath35 ) process . the dashed line represents the total cross section @xmath36 of all processes @xcite.,scaledwidth=45.0% ] @xmath0-bubbles occur as an irradiation damage . they change the physical properties of the irradiated surface and increase the erosion rate @xcite . @xmath0-bubbles are metal pockets filled with hydrogen molecular gas . the tendency to form bubbles depends on the proton energy , integrated proton flux ( dose ) , temperature of the target , crystallographic orientation of the irradiated surface as well as on impurities and defects in the sample @xcite . it is known from terrestrial laboratory experiments that for aluminum the minimum dose of protons above which the process occurs is @xmath37 @xmath38 @xmath2 ( e.g. * ? ? ? the temperature range in which bubbles were observed is between @xmath39 and @xmath40 k ( e.g. * ? ? ? * ; * ? ? ? the procedure that was used to estimate the critical temperature ( @xmath40 k ) above which the process of bubble formation was stopped due to the bubble cracking mechanism was as follows . the aluminum target was irradiated by a flux of protons at room temperature . when irradiation of the sample was stopped , the probe was heated up to higher temperatures . a significant increase of both , the surface density and sizes of the bubbles has been observed until the critical temperature was reached . that procedure , used by the authors , allows to capture more hydrogen by the vacancies since during the irradiation , and at room temperature the vacancies will collect more hydrogen than at elevated temperatures . the vacancy is a missing ion or point defect in metal lattice @xcite . also a diffusion of hydrogen in aluminum at room temperature is much lower than at temperatures reaching @xmath41 k @xcite . in space a probe is bombarded by the solar protons at the temperature which is related to its orbit . therefore , the procedure presented by @xcite does not match the bubble formation mechanism under real space conditions . hydrogen atoms are much smaller than metal ions , but they can introduce strain in a metal lattice when being absorbed as interstitial ions @xcite . they can also change the electronic structure of near neighbor metal ions @xcite . that causes an increase of the lattice energy . it may be decreased by the aggregation of the interstitial hydrogen atoms into hydrogen atom clusters , and then molecular hydrogen bubbles @xcite . hydrogen could not agglomerate into @xmath0-clusters without the presence of vacancies . for instance a single vacancy in aluminum can trap up to twelve h atoms . for comparison , a vacancy in iron can trap only up to six h atoms @xcite . hydrogen atoms which do not constitute the @xmath0 molecules and which are not trapped by the vacancies , diffuse through the metal lattice . molecular hydrogen bubbles were observed also on different materials than aluminum . copper , tungsten , palladium and iron were investigated ( e.g. * ? ? ? bubbles are not forming on tantalum and vanadium . these metals are well known as _ blistering - resistant _ materials @xcite . however , they are not suitable for space applications where the surface reflectivity plays a crucial role , e.g. in the solar sail propulsion technology since their reflectance is @xmath42 lower than that of aluminum @xcite . growth of molecular hydrogen bubbles will be possible in the interplanetary space if the criterion of the minimum dose of protons is fulfilled . the temperature of the sample has to be high enough to start the bubble formation , but not too high to lose hydrogen much too rapidly due to the high diffusivity of hydrogen in metals . under the simplifying assumption that the sun generates only mono - energetic 5 kev protons , the criterion of minimum dose of protons will be fulfilled after 116 days for 1 au distance orbit from the sun . obviously , taking into account proton fluxes from the whole energy range , the criterion will be fulfilled much earlier . the temperature of a foil placed in a given distance @xmath19 from the sun can be calculated from the balance of heating and cooling by : @xmath43 here , @xmath44 is the area of the sample which absorbs the electromagnetic radiation , while @xmath45 is the area which emits the heat by radiation . hence , the ratio @xmath46 equals @xmath47 . @xmath48 is the stefan - boltzmann constant , @xmath49 states for solar constant . the thermo - optical parameters have been provided by the manufacturer of the @xmath50 foil , the ube company . solar absorptance @xmath51 and normal emittance @xmath52 are @xmath53 and @xmath54 , respectively . the foil temperature as a function of distance from the sun is represented by solid line in fig . [ ube_temperature ] . note , that the heat released by stopped protons is negligible small in comparison to the sun s input . the red area ( 570 - 300 k ) is the temperature range in which the bubble formation has been confirmed by the terrestrial laboratory experiments . unfortunately , commonly used experimental procedures to estimate the maximum temperature at which the bubble formation is stopped , are not suitable for the real space conditions . the dark - red area represents temperatures at which the bubble formation has been confirmed by the first experimental findings performed at dlr . some of the results , needed to validate the thermodynamic model are shown in section [ results ] . the bubble growth continues even when the probe is moving outwards from the sun ( @xmath55 2.8 au , grey area ) . obviously , at larger distances the bubble growth slows down , since the probe is being bombarded by the smaller proton fluxes , see eq . [ flux_r ] . foil covered on both sides with @xmath12 nm vacuum deposited aluminum layer as a function of the distance from the sun . the red area represents temperature range in which the bubble formation was reported in the literature . the dark - red area is the temperature range in which the formation has been confirmed by studies performed at dlr.,scaledwidth=50.0% ] in the following , a thermodynamic model of bubble growth is proposed . the model is based on the assumption that the growth proceeds quasi - static i.e. during a @xmath56 period of time @xmath57 a small portion of @xmath0-molecules , @xmath58 , is added to the @xmath59 bubble and a thermodynamic equilibrium is rapidly re - established . for simplicity it is assumed that a single bubble is a half of a sphere with a radius of @xmath60 . the gas within a bubble behaves to a good approximation like an ideal gas : @xmath61 where @xmath62 is the pressure of the gas , @xmath63 is the boltzmann constant , @xmath64 denotes the temperature of the sample , @xmath65 is the number of time steps up to a given state of bubble growth , hence the irradiation time of the sample after @xmath66 time steps is @xmath67 . the number of recombined h atoms , subtracted by those which diffuse from the sample out ( @xmath68 ) is : @xmath69 the term @xmath70 determines how much hydrogen diffuses from the sample out ( per unit area and time ) . therefore , by dimension it is a flux of outflowing hydrogen from the specimen . its constant value results from the following fact . the model assumes that the sample is exposed to the protons having kinetic energies from evs to 8 kev . according to the data ( see , fig . [ p_flux ] ) , the magnitude of the proton flux remains almost constant for the considered energy range . therefore , the sample is uniformly populated by the protons ( h atoms after recombination ) to a depth of @xmath71 . the @xmath71 is calculated for the fastest protons . therefore , there is no differentiation of hydrogen concentration with respect to the depth . in eq . [ balance ] @xmath72 is the area of the sample irradiated by the protons , @xmath73 is the area of the sample covered by the bubbles . @xmath74 is the factor of backscattered ions . if @xmath74 is 1 then all of the incident ions are backscattered . if @xmath74 is 0 then all of the incident ions penetrate the target . @xmath75 is the diffusion coefficient for h atoms in a given material , @xmath76 is the number density of h atoms which may diffuse through the lattice in the @xmath77 period of time , @xmath78 is the so - called projected range . it is defined as an average value of the depth to which a charged particle will penetrate in the course of slowing down to rest . this depth is measured along the initial direction of the particle , and it depends on the kinetic energy of the particle @xcite . the number of hydrogen molecules added in the @xmath77 period of time to the @xmath79 bubble @xmath80 is constant and given by : @xmath81 here @xmath47 denotes that a single @xmath0 molecule consists of two h atoms , @xmath82 is a matrix , its role is to redistribute certain number of @xmath0 molecules into the bubbles . the input pattern of @xmath0 molecules into the bubbles follows experimental findings of kamada et al . @xmath83 is the total number of bubbles on the irradiated sample . while 100% of protons recombine into h atoms in the metal lattice , only a part of them recombine to @xmath84 molecules @xcite . hence the @xmath85 coefficient is the ratio between the number of @xmath84-molecules and the h - atoms in the lattice . the @xmath0 molecule is formed when electrons of two h atoms have anti - parallel spin @xmath86 , otherwise the molecule can not be created . therefore , at most half of the h atoms can form @xmath0 molecules , hence @xmath87 . not all of the @xmath84-molecules will merge into @xmath84-clusters and finally form @xmath84-bubbles . thus , the coefficient @xmath88 denotes the ratio of the number of @xmath84-molecules inside and outside the bubbles . the first step to estimate the radius of the @xmath59 bubble is to calculate the helmholtz free energy of the whole configuration , @xmath89 . since the free energy is an additive quantity , the total free energy of bubble formation is a sum of following quantities : free energy of @xmath0 gas inside the @xmath59 bubble ( @xmath90 ) , of the metal surface deformation ( @xmath91 ) caused by the bubble growth itself , of the surface free energy ( @xmath92 ) of the bubble cap , of the free energy of @xmath84-molecules ( @xmath93 ) and of h - atoms ( @xmath94 ) placed outside the bubbles but within the metal lattice . the helmholtz free energy of the whole configuration described above is then : @xmath95 the next step is to estimate the free energy of the @xmath59 bubble . it consists of the free energy of the gas filled in the bubble , the free energy of metal deformation , and of the bubble cap surface free energy . using the thermodynamic relation between gas pressure and its helmholtz free energy @xmath96 together with the equation of state eq . [ pressure ] , the free energy of a gas within the @xmath59 bubble is : @xmath97 where @xmath98 is the maximum volume of a given bubble . the model assumes that two @xmath0 molecules form the smallest ( `` initial '' ) possible bubble , its volume is denoted by @xmath99 . the radius of such a bubble is approximately @xmath100 bohr radii @xcite . every bubble will crack if the pressure of the gas inside is higher than the pressure exerted by the metal deformation of the cap . the relation between the pressure of the gas , surface tension @xmath101 , and the bubble radius corresponding to @xmath102 is @xcite : @xmath103 since the sample is placed in vacuum , the pressure outside the bubble is set to zero . the free energy of metal deformation @xmath91 caused by the gas pressure inside the bubble with radius @xmath60 can be found in @xcite , and is given by : @xmath104 here @xmath105 is the poisson coefficient , i.e. ratio of transverse to axial strain of a sample material , @xmath106 is the young s module . the free energy of a surface of a cap of the @xmath59 bubble is given by @xcite : @xmath107 the helmholtz free energy of the @xmath84-molecules located at certain positions in the metal lattice but outside the bubbles is calculated in the form @xmath108 . where @xmath109 is the internal energy of molecules / atoms located at certain positions in the metal lattice . applying the statistical definition of the entropy @xmath110 , this free energy is : @xmath111 , \end{aligned}\ ] ] where @xmath112 is the total number of @xmath0 molecules inside the sample , @xmath113 is the binding energy of @xmath84 molecule to a vacancy . a detailed derivation of the eq . [ f_h2 ] is presented in [ app_f_h2 ] . @xmath114 is the number of lattice sites , which can be expressed by : @xmath115 where @xmath116 is the avogadro s number . @xmath117 is the molar mass of the sample s material . the helmholtz free energy of h atoms located at certain positions within the metal lattice is : @xmath118,\ ] ] where @xmath119 is the migration energy of the h atom in the metal lattice , and @xmath120 is the total number of h atoms in the sample . a detailed derivation of the eq . [ f_h ] can be found in [ app_f_h ] . since now each term of eq . [ f_system ] is determined , the next step is to estimate the radius @xmath60 of the @xmath59 bubble at given time @xmath121 . this will be achieved by assuming that the process of bubble growth proceeds quasi - static in thermodynamic equilibrium : @xmath122 this condition leads to the following fifth order equation for @xmath60 : @xmath123 = 0,\end{aligned}\ ] ] @xmath124 is defined below in eq . [ dyn_model ] , @xmath125 denotes the abbreviation : @xmath126 the derivatives of the helmholtz free energy , of the gas inside the @xmath59 bubble , of metal deformation caused by the bubble , of the @xmath59 bubble cap surface , of @xmath0 molecules , and of h atoms with respect to the number of @xmath0 molecules added at the @xmath56 time step to the @xmath59 bubble are presented in [ a_f_system ] . a realistic model of bubble radius growth , @xmath127 , can be estimated by following gedankenexperiment . obviously at the beginning of the bubble growth process , the differential increase of the bubble radius is higher than at its end . it is implied , that the number of @xmath0 molecules in the system is conserved and at each time step one of them merge into a bubble . after @xmath128 the bubble consists of @xmath129 molecules , hence the number of molecules increases by @xmath130 . at the time @xmath131 the bubble consists of @xmath132 molecules , hence the number increase is now @xmath133 , and so on . therefore @xmath134 is : @xmath135 the exponent @xmath136 is a model parameter of the bubble growth . the value @xmath137 corresponds to the gedankenexperiment presented above . however , the true value of the @xmath136 parameter differs from that . in the process of bubble growth , particles ( the hydrogen ) are added to the system i.e. the probe is permanently irradiated by the protons , they penetrate the target and recombine to the hydrogen . on the other hand , both , due to the diffusion process and bubble cracking , some hydrogen atoms leave the system . therefore , the number of hydrogen atoms in the system is not conserved . hence , a series of experiments have been performed to estimate a realistic @xmath136 parameter , results are presented in section [ results ] . the momentum transfer of a photon to an ideal reflecting surface is given by @xmath138 , where the factor 2 is just in accordance with specular reflectivity . certainly , the surface quality will suffer during the irradiation with protons from progressing bubble formation . at time @xmath139 the foil has not been exposed to the electromagnetic radiation and/or charged particles , and is considered to be a perfect mirror with the reflectivity of @xmath140 . it means that all of the incident light rays are reflected perfectly , no light ray is absorbed or diffusively reflected by the target . later , when the foil has been irradiated by a flux of protons and molecular hydrogen bubbles have been formed on its surface , the reflectivity of the degraded foil will be reduced . this deterioration is calculated in the following way : the foil is covered by a grid with a fixed single cell size of @xmath141 , see fig . [ cells ] . the reflectivity of a single cell is by definition @xmath142 , where @xmath143 is momentum transfer of a photon to the @xmath59 cell of the degraded foil , while @xmath144 is the momentum transfer of a photon to the @xmath59 cell of a perfect mirror . .,scaledwidth=45.0% ] therefore , taking into account all cells , one has : @xmath145 here @xmath146 is the number of cells . the path of photons is directed parallel to the foil surface normal . therefore , at time @xmath139 the foil was a perfect mirror without surface imperfections and @xmath147 . later , when the surface is populated with bubbles , @xmath148 will vary between @xmath149 and @xmath150 . thus , eq . [ reflectivity_common ] reduces to : @xmath151 a following set of experiments were performed . three probes ( a1 , a2 , and a3 ) were exposed to a flux of 2.5 kev protons , each one with longer irradiation time , see table [ test_parameters ] , where @xmath152 is a number of days in space until a probe will collect a given dose of protons . results are shown in fig . [ dose_dep ] . from top to bottom , the pictures correspond to the probes a1 , a2 , and a3 , respectively . average sizes of bubbles have been estimated to @xmath153 @xmath4 m , @xmath154 @xmath4 m , and @xmath155 @xmath4 m for probe a1 , a2 , and a3 , respectively . there is a strict correlation between a dose of protons and the average bubble size for a given population . the higher the proton dose , the larger the bubble sizes . examining the electron microscope pictures , the surface density of bubbles has been estimated to @xmath156 @xmath2 . we have confirmed formation of molecular hydrogen bubbles by a number of experiments . we have varied protons flux , energy , and specimens temperature . bubbles were observed for specific parameters range . fig . [ ube_temperature ] represents our findings . the here used three experimental findings are the minimum number of specimens necessary to validate the model . [ test_parameters ] bubble growth in blistering process is dominated by diffusion of hydrogen atoms into the bubbles . a similar problem of the bubble growth ( ostwald ripening ) was widely discussed in literature ( e.g. * ? ? ? * ; * ? ? ? * ; * ? ? ? * ; * ? ? ? * ; * ? ? ? * ; * ? ? ? it has been found the power law @xmath157 for the average bubble radius @xmath158 in the systems with the total mass being a conserved quantity . this type of the systems exhibits diffusion limited growth and is well described in terms of the lifshitz - slyozov - wagner ( lsw ) theory @xcite . the hydrogen bubbles follow the diffusion limited growth and the question can be raised whether the lsw theory applies to them . in this case the growth rate of the bubble average radius @xmath159 could be represented by the following phenomenological equation : @xmath160 \,\ , , \label{eqls}\ ] ] similarly as in @xcite , where @xmath161 is the diffusion coefficient of hydrogen atoms , @xmath162 is a parameter which depends on the surface tension @xmath101 of a bubble , the hydrogen atom volume @xmath163 , the concentration @xmath164 of hydrogen atoms far beyond the bubble and temperature t , @xmath165 is the difference of concentration of hydrogen atoms at the bubble boundary and @xmath164 . in the lsw approach , the total mass of a system is a conserved quantity , in consequence @xmath166 , and the solution of eq . [ eqls ] takes the form of @xmath167 . the three probes @xmath168 , @xmath169 , @xmath170 from the pictures in fig . [ dose_dep ] were exposed to a constant proton flux . taking into account that the amount of the hydrogen atoms produced by the proton flux is related directly to the existing electronic structure of the irradiated probes as well as that the thickness of the superficial layer including the molecular hydrogen bubbles is relatively constant in size ( it only shifts deeper into the sample after the superficial bubbles break ) then the system of the growing bubbles resembles the total mass conservation system . hence , it could be expected that at least the largest bubbles which appear on the irradiated probes surface follow the growth law @xmath171 as well as they undergo coalescence phenomena . the latter property is evident , e.g. for probe @xmath170 in fig . [ models_distribution_data ] . concerning the question of the possible existence of the @xmath171 scaling , the average bubble radius , respectively for the probe @xmath168 , @xmath169 , @xmath170 ( table 2 ) has been divided by the duration of the proton flux exposure in the power of @xmath172 , i.e. , @xmath173 , @xmath174 and @xmath175 . all scaled radii take the same value close to @xmath176 . in addition , in fig . [ models_distribution_data ] , the distribution of the bubble radii , @xmath177 of the growing bubbles has been plotted . it can be observed that the largest bubbles seem to follow the @xmath171 power growth law because their scaled distributions coincide . the left hand side of the bubble radius distribution is influenced by the bubbles which were formed at later time moments and it is the reason for the strong deviation of their size from the @xmath171 power law . it can be concluded from the surface analysis of the probes @xmath168 , @xmath169 and @xmath170 that their degradation after they were exposed to proton flux is not faster than it is predicted by lsw theory . however , it is necessary further investigation on the problem both experimentally and theoretically . for bubbles in fig . [ dose_dep ] , respectively for probe a1 , a2 and a3 . bottom plot , the same as top plot but for the scaled radius , @xmath177.,scaledwidth=45.0% ] for numerical simulation a @xmath178 foil was specified . that choice allows to simulate a smaller number of bubbles , i.e. it decreases the computation time of the simulation . it implies also an important assumption that surface arrangement of the bubbles is isotropic i.e. any @xmath178 area of the irradiated sample is indistinguishable . table [ model_parameters ] collects all of the model parameters used in the simulation . the first set of parameters characterize mechanical and thermo - optical properties of vacuum deposited aluminum on ubs s @xmath11 foil . second set specifies values of the parameters which have been used to fit the model to the experimental data presented here . to fit the proper gradient of bubble growth , the @xmath136 parameter was set to @xmath179 , see eq . [ dyn_model ] . comparison of the average bubble size of the experimental and numerical findings are drawn in the top plot of the fig . [ model ] . the @xmath88 parameter was set to @xmath180 . it determines the height of the curve . a decrease of the specular reflectivity of the foil as a function of time is shown in the bottom plot of the fig . [ model ] . the decrease of the reflectivity is @xmath181 , @xmath182 , and @xmath183 % in comparison to the non - irradiated foil for @xmath184 , @xmath185 , and @xmath186 days , respectively . clearly , the larger the bubble sizes , the larger the specular reflectivity decrease @xmath187 in comparison to the non - irradiated foil . a distribution of the bubbles at three different time steps : @xmath188 , @xmath185 , and @xmath186 days is shown in fig . [ models_distribution ] . during time , the probe collects higher dose of protons , therefore , the distribution drifts i.e. size of bubbles increases . at time @xmath189 days most of the bubbles have sizes in range @xmath190 to @xmath191 @xmath4 m , there are only a few which have sizes larger than @xmath192 @xmath4 m . [ model_parameters ] @xmath193 sample at three different time steps : @xmath194 , @xmath185 , and @xmath186 @xmath152.,scaledwidth=50.0% ] it has been proven that thermodynamic model is a flexible tool to simulate and to reproduce the real growth of the molecular hydrogen bubbles . however , the estimated @xmath136 and @xmath88 parameters are applicable only for the here presented experimental findings . these parameters depend on type and temperature of the irradiated material . therefore , change of the material type and the experimental conditions requires an update of the model parameters . the time evolution of decrease of the specular reflectivity @xmath187 is a model prediction . it is highly required to perform experimental confirmation of that findings , since the real reflectivity decrease can differ from that estimated here . for sure , the here presented experimental findings show that physical parameters of the metal surface , e.g. roughness , reflectivity , are significantly changed under conditions as prevalent in the interplanetary space . therefore , statement present in the ecss standard @xcite that metals do not suffer from space - environment is not longer valid . the thermodynamic model requires further improvements . the considered aging factor , the solar protons , are not the only one which can influence the bubble growth process . the solar wind is also essentially made up of electrons and small proportion of heavier ions @xcite . additionally , electromagnetic radiation in the lower wavelength range has also to be taken into consideration . these degradation factors can slow down the bubble growth . the growth deceleration can be explained as follows . hydrogen molecule dissociate at the energy of @xmath195 ev @xcite . the dissociation may be caused by the uv - light with the wavelengths @xmath196 nm . the @xmath0 gas within the bubbles can then be partially dissociated , and h atoms can diffuse easily through the bubble caps . as a result the bubble growth process may slow down . the deceleration can be strengthen by heavier ions generated by the sun e.g. @xmath136-particles . their diameter is much larger than that of protons or electrons , hence , collisions between the @xmath0 molecules and the @xmath136-particles within the bubbles can additionally increase the dissociation efficiency . the present condition for the bubble crack mechanism , eq . [ cracking_condition ] , assumes that the pressure outside the bubbles is negligible small . under the real space conditions the electromagnetic radiation will exert a pressure on the caps , hence , their sizes may be smaller . on the other hand , bubble caps loose thermal contact with the base material and they become overheated @xcite . as a consequence the caps can brake and the @xmath0 gas can be released . that aspect of the blistering process needs to be examined . by these reasons further experimental studies are planned , e.g. the mentioned influence of the uv - light on the bubble growth dynamics . we would like to express our special thanks to dr . herbert juling who performed electron microscope measurements and mrs . shiho otsu from ube industries ltd . who provides us the foils . here @xmath109 is the internal energy of the @xmath84 molecules located at certain positions in the metal lattice , @xmath110 denotes the entropy , while @xmath198 represents the number of ways in which the @xmath84 molecules can be arranged on the @xmath114 lattice sites ( eq . [ lattice_sites ] ) . the number of @xmath84 molecules located outside the bubbles at certain positions in the metal lattice is @xmath199 . where @xmath200 is the total number of @xmath84 molecules in the sample , while @xmath201 is the total number of @xmath84 molecules within all bubbles . the summation over the number of time steps @xmath202 counts the number of @xmath84 molecules in the @xmath59 bubble . the second summation over number of bubble @xmath59 counts the number of @xmath84 molecules within all bubbles . therefore , performing the subtraction one gets the total number of @xmath0 molecules outside all bubbles , located at certain positions in the metal lattice . the entropy @xmath203 of the collection of the @xmath84 molecules placed on a lattice sites is @xcite : @xmath204 ! } , \\ & \cong - k_{\rm{b } } \left(n_{\rm{h_{2}}}^{\rm{t } } - \sum_{\rm{i}}^{n_{\rm{b}}^{\rm{t } } } \sum_{\rm{j}}^{\rm{n } } n_{\rm{h_{2 } , i , j}}\right ) \ln \left[\frac{n_{\rm{h_{2}}}^{\rm{t } } - \sum_{\rm{i}}^{n_{\rm{b}}^{\rm{t } } } \sum_{\rm{j}}^{\rm{n } } n_{\rm{h_{2 } , i , j}}}{n_{\rm{0}}}\right].\end{aligned}\ ] ] where the @xmath113 is the binding energy of the @xmath84 molecule to a vacancy @xcite . the internal energy of @xmath84 molecules located in the metal lattice sites is a product of the binding energy of a single @xmath84 molecule and the number of molecules . where @xmath120 is the total number of h atoms in the sample , so the number counts all of the incident hydrogen ions which have recombined into hydrogen atoms . some of the hydrogen atoms have recombined to @xmath0 molecules and some of the molecules are forming the bubbles . hence to get the number of h atoms located on the lattice sites one has to subtract the total number of hydrogen atoms @xmath208 and those hydrogen atoms which build @xmath0 clusters and @xmath0 bubbles . the reason of the factor @xmath209 is that a single @xmath84 molecule consists of two h atoms . where @xmath119 is the migration energy of the h atom in the metal lattice . the migration energy is defined as the minimum energy which has to be added to the h atom in order to remove it from the lattice site . [ [ a_f_system ] ] the derivatives of helmholtz free energy of : gas of the @xmath79 bubble , metal deformation caused by the bubble , surface of the @xmath59 bubble cap , @xmath0 molecules , and @xmath211 atoms located outside the bubbles . ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ the assumption is fulfilled when the time scale of the bubble growth is longer than the time scale of the formation of a @xmath0 molecule out of two h atoms . the thermodynamic equilibrium is rapidly re - established after merging a @xmath0 molecule to a given @xmath59 bubble during a given time step . condition [ condition ] can be written as a sum : derivatives of the free energy of the gas in the @xmath59 bubble , of metal deformation caused by the bubble , surface of the @xmath59 bubble cap , and of @xmath0 molecules and h atoms located on the lattice sites with respect to the number of @xmath0 molecules that merge on each time step to a bubble , will be calculated separately . by use of the helmholtz free energy of the gas , eq . [ f_gas ] , the derivative is : banyard k. e. , continuum - distorted - wave calculations for rearrangement cross sections and their sensitivity to improvements in the target wave function : proton - helium collisions , physical review a 16 , 129 , 1977 . canham l. t. , dyball m. r. , leong w. y. , houlton m. r. , cullis a. g. , smith p. w. , radiative recombination channels due to hydrogen in crystalline silicon , materials science an engineering b4 , 41 , 1989 . heltzel s. , semprimoschnig c. , eesbeek m. v. , environmental testing of thermal control materials at elevated temperature and intense ultraviolet radiation , journal of spacecraft and rockets 46 , 248 , 2009 . lura f. , verkhovtsva e. t. , yaremennko v. i. , telepnev v. d. gas - jet simulator of solar vuv and soft x - ray radiation and irradiation effect on some materials , proceedings of the @xmath221 international symposium on materials in space environment , toulouse , france , 119 , 1997 . myers s. m. , baskes , m. i. , birnbaum , h. k. , corbett , j. w. , deleo , g. g. , estreicher , s. k. , haller , e. e. , jena , p. , johnson , n. m. , kirchheim , r. , pearton , s. j. , stavola , m. j. , hydrogen interactions with defects in crystalline solids , review of modern physics 64 , 559 , 1992 . penalba m. , arnau a. , echenique p.m. , electron capture and loss processes for protons in aluminum : comparison between conduction band electron - hole assisted and plasmon assisted auger processes , nuclear instruments and mothods in physics research b48 , 138 , 1990 .

the widespread use of metallic structures in space technology brings risk of degradation which occurs under space conditions . new types of materials dedicated for space applications , that have been developed in the last decade , are in majority not well tested for different space mission scenarios . very little is known how material degradation may affect the stability and functionality of space vehicles and devices during long term space missions . our aim is to predict how the solar wind and electromagnetic radiation degrade metallic structures . therefore both experimental and theoretical studies of material degradation under space conditions have been performed . the studies are accomplished at german aerospace center ( dlr ) in bremen ( germany ) and university of zielona gra ( poland ) . the paper presents the results of the theoretical part of those studies . it is proposed that metal bubbles filled with hydrogen molecular gas , resulting from recombination of the metal free electrons and the solar protons , are formed on the irradiated surfaces . a thermodynamic model of bubble formation has been developed . we study the creation process of @xmath0-bubbles as function of , inter alia , the metal temperature , proton dose and energy . our model has been verified by irradiation experiments completed at the dlr facility in bremen . consequences of the bubble formation are changes of the physical and thermo - optical properties of such degraded metals . we show that a high surface density of bubbles ( up to @xmath1 @xmath2 ) with a typical bubble diameter of @xmath3@xmath4 m will cause a significant increase of the metallic surface roughness . this may have serious consequences to any space mission . changes in the thermo - optical properties of metallic foils are especially important for the solar sail propulsion technology because its efficiency depends on the effective momentum transfer from the solar photons onto the sail structure . this transfer is proportional to the reflectivity of a sail . therefore , the propulsion abilities of sail material will be affected by the growing population of the molecular hydrogen bubbles on metallic foil surfaces . space environmental effects , recombination , hydrogen embrittlement , blistering

the non - equilibrium dynamics of disordered systems has been much studied both experimentally and theoretically ( see for instance the reviews @xcite and references therein ) . in numerical simulations , the main limitation is that the equilibrium time @xmath16 needed to converge towards equilibrium for a finite system of linear size @xmath17 grows very rapidly with @xmath17 . within the droplet scaling theory proposed both for spin - glasses @xcite and for the directed polymer in a random medium @xcite , the non - equilibrium dynamics is activated with barriers scaling as a power law @xmath18 with some barrier exponent @xmath19 that is independent of temperature and disorder strength . the equilibrium time @xmath16 then grows as @xmath20 this logarithmic scaling has been used to fit numerical data for disordered ferromagnets @xcite and spin - glasses @xcite . other authors , both for disordered ferromagnets @xcite and spin - glasses @xcite prefer a scenario corresponding to logarithmic barriers @xmath21 , so that the equilibrium time @xmath16 scales as a power - law @xmath22 where the exponent @xmath23 is non - universal and depends on the temperature @xmath24 as well as on the disorder strength @xmath25 . in the field of directed polymers or elastic lines in random media , the fit based the algebraic form of eq . [ lz ] used initially by many authors @xcite has been now excluded by more recent work @xcite , and has been interpreted as an artefact of an initial transient regime @xcite . the reason why the debate between the two possibilities of eqs [ defpsi ] and [ lz ] has remained controversial over the years for many interesting disordered models is that the equilibrium time @xmath16 grows numerically so rapidly with @xmath17 that @xmath16 can be reached at the end of dynamical simulations only for rather small system sizes @xmath26 . for instance , in monte - carlo simulations of 2d or 3d random ferromagnets @xcite or spin - glasses @xcite , the maximal equilibrated size is usually only of order @xmath27 lattice spacings . even faster - than - the - clock monte carlo algorithms @xcite , where each iteration leads to a movement , become inefficient because they face the futility problem @xcite : the number of different configurations visited during the simulation remains very small with respect to the accepted moves , i.e. the system visits over and over again the same configurations within a given valley before it is able to escape towards another valley . a recent proposal to improve significantly monte carlo simulations of disordered systems consists in introducing some renormalization ideas @xcite . taking into account these difficulties , a natural question is whether it could be possible to obtain informations on the equilibrium time @xmath16 _ without simulating the dynamics_. in previous works @xcite , we have proposed for instance to study the flow of some strong disorder renormalization procedure acting on the transitions rates of the master equation . however this approach is expected to become asymptotically exact only if the probability distribution of renormalized transitions rates flows towards an infinite disorder fixed point , i.e. only for the activated scaling of eq . [ defpsi ] . in the present paper , we test another strategy to compute @xmath1 which is a priori valid for any dynamics defined by a master equation satisfying detailed balance : it is based on the computation of the first excited energy @xmath4 of the quantum hamiltonian @xmath0 that can be associated to the master equation . this approach makes no assumption on the nature of the dynamics and is thus valid both for activated or non - activated dynamics ( eqs [ defpsi ] or [ lz ] ) . the mapping between continuous - time stochastic dynamics with detailed balance and quantum schrdinger equations is of course very well - known and can be found in most textbooks on stochastic processes ( see for instance @xcite ) . however , since it is very often explained on special cases , either only in one - dimension , or only for continuous space , or only for fokker - planck equations , we stress here that this mapping is valid for any master equation satisfying detailed balance ( see more details in section [ secquantum ] ) . in the field of disordered systems , this mapping has been very much used for one - dimensional models ( see the review @xcite and references therein , as well as more recent works @xcite ) , but to the best of our knowledge , it has not been used in higher dimension , nor for many - body problems . in the field of many - body dynamics without disorder , this mapping has been already used as a numerical tool to measure very precisely the dynamical exponent @xmath28 of the two dimensional ising model at criticality @xcite . the paper is organized as follows . in section [ secquantum ] , we recall how the master equation can be mapped onto a schrdinger equation in configuration space , and describe how the equilibrium time @xmath1 can be obtained from the associated quantum hamiltonian . we then apply this method to two types of disordered models : section [ secrw ] concerns the problem of a random walk in a two - dimensional self - affine potential , and section [ secsk ] is devoted to the the dynamics of the sherrington - kirkpatrick spin - glass model . our conclusions are summarized in section [ secconclusion ] . in statistical physics , it is convenient to consider continuous - time stochastic dynamics defined by a master equation of the form @xmath29 that describes the the evolution of the probability @xmath30 to be in configuration @xmath31 at time t. the notation @xmath32 represents the transition rate per unit time from configuration @xmath33 to @xmath31 , and @xmath34 represents the total exit rate out of configuration @xmath31 . let us call @xmath35 the energy of configuration @xmath31 . to ensure the convergence towards boltzmann equilibrium at temperature @xmath24 in any finite system @xmath36 where @xmath37 is the partition function @xmath38 it is sufficient to impose the detailed - balance property @xmath39 as is well known ( see for instance @xcite ) the master equation operator can be transformed into a symmetric operator via the change of variable @xmath40 the function @xmath41 then satisfies an imaginary - time schrdinger equation @xmath42 where the quantum hamiltonian has the generic form of an anderson localization model in configuration space @xmath43 the on - site energies read @xmath44 whereas the hopping terms read @xmath45 to have the detailed balance of eq . [ detailed ] , it is convenient to rewrite the rates in the following form @xmath46 where @xmath47 means that the two configurations are related by an elementary dynamical move , and where @xmath48 is an arbitrary symmetric function : @xmath49 . to have the detailed balance property of eq . [ detailed ] , the simplest choice in eq . [ wratesgeneral ] corresponds to @xmath50 @xmath51 then the hopping terms of the quantum hamiltonian are simply @xmath52 i.e. the non - vanishing hopping terms are not random , but take the same constant value @xmath53 as in usual anderson localization tight binding models . the on - site energies are random and read @xmath54 in numerical simulations , one of the most frequent choice corresponds to the metropolis transition rates @xmath55 \label{metropolis}\end{aligned}\ ] ] in eq . [ wratesgeneral ] , this corresponds to the choice @xmath56 in the quantum hamiltonian , the hopping terms then read @xmath57 and the on - site energies are given by @xmath58 \label{epsmetro}\end{aligned}\ ] ] let us note @xmath59 the eigenvalues of @xmath0 and @xmath60 the associated normalized eigenvectors @xmath61 the decomposition onto these eigenstates of the evolution operator @xmath62 @xmath63 yields the following expansion for the conditional probability @xmath64 to be in configuration @xmath31 at @xmath65 if one starts from the configuration @xmath66 at time @xmath67 @xmath68 the quantum hamiltonian @xmath0 has special properties that come from its relation to the dynamical master equation : \(i ) the ground state energy is @xmath3 , and the corresponding eigenvector is given by @xmath69 where @xmath37 is the partition function of eq . [ partition ] . this corresponds to the convergence towards the boltzmann equilibrium in eq . [ relationppsi ] for any initial condition @xmath66 @xmath70 \(ii ) the other energies @xmath71 determine the relaxation towards equilibrium . in particular , the lowest non - vanishing energy @xmath4 determines the largest relaxation time @xmath72 of the system @xmath73 since this largest relaxation time represents the equilibrium time , i.e. the characteristic time needed to converge towards equilibrium , we will use the following notation from now on @xmath74 the conclusion of this section is thus that the relaxation time @xmath1 can be computed without simulating the dynamics by any eigenvalue method able to compute the first excited energy @xmath4 of the quantum hamiltonian @xmath0 ( where the ground state is given by eq . [ psi0 ] and has for eigenvalue @xmath3 ) . in the following subsection , we describe one of such methods called the conjugate gradient method . the conjugate gradient method has been introduced as an iterative algorithm to find the minimum of functions of several variables with much better convergence properties than the steepest descent method @xcite . it can be applied to find the ground state eigenvalue and the associated eigenvector by minimizing the corresponding rayleigh quotient @xcite @xmath75 the relation with the lanczos method to solve large sparse eigenproblems is discussed in the chapters 9 and 10 of the book @xcite . in the following , we slightly adapt the method described in @xcite concerning the ground state @xmath76 to compute instead the first excited energy @xmath4 : the only change is that the rayleigh quotient has to be minimized within the space orthogonal to the ground state . in the remaining of this paper , we apply this method to various disordered models to obtain the probability distribution of the equilibrium time @xmath16 over the samples of a given size @xmath17 . more precisely , since the appropriate variable is actually the equilibrium barrier defined as @xmath77 we will present numerical results for the probability distribution @xmath78 for various sizes @xmath17 . over the disordered samples of sizes @xmath79 for the random walk in a two - dimensional self - affine random potential of hurst exponent @xmath80 : ( a ) probability distribution @xmath81 for @xmath82 ( inset : the corresponding distributions @xmath83 of the rescaled variable @xmath84 are shown in log scale for @xmath85 ) ; ( b ) the log - log plots of the disorder - average @xmath86 and of the width @xmath87 corresponds to the barrier exponent @xmath88 ( eq . [ psiboth ] ) , title="fig:",height=226 ] over the disordered samples of sizes @xmath79 for the random walk in a two - dimensional self - affine random potential of hurst exponent @xmath80 : ( a ) probability distribution @xmath81 for @xmath82 ( inset : the corresponding distributions @xmath83 of the rescaled variable @xmath84 are shown in log scale for @xmath85 ) ; ( b ) the log - log plots of the disorder - average @xmath86 and of the width @xmath87 corresponds to the barrier exponent @xmath88 ( eq . [ psiboth ] ) , title="fig:",height=226 ] in this section , we apply the method of the previous section to the continuous - time random walk of a particle in a two - dimensional self - affine quenched random potential of hurst exponent @xmath80 . since we have studied recently in @xcite the very same model via some strong disorder renormalization procedure , we refer the reader to @xcite and references therein for a detailed presentation of the model and of the numerical method to generate the random potential . here we simply recall what is necessary for the present approach . we consider finite two - dimensional lattices of sizes @xmath89 . the continuous - time random walk in the random potential @xmath90 is defined by the master equation @xmath91 where the transition rates are given by the metropolis choice at temperature @xmath24 ( the numerical data presented below correspond to @xmath92 ) @xmath93 where the factor @xmath94 means that the two positions are neighbors on the two - dimensional lattice . the random potential @xmath90 is self - affine with hurst exponent @xmath80 @xmath95 ^ 2 } \opsimeq _ { \vert \vec r - \vec r \ ' \vert \to \infty } \vert \vec r - \vec r \ ' \vert^{2h } \label{correu2d}\end{aligned}\ ] ] on fig . [ figu2d ] ( a ) , we show the corresponding probability distribution @xmath78 for various sizes @xmath96 with a statistics of @xmath97 disordered samples . as shown by the log - log plots of fig . [ figu2d ] ( b ) , we find that the disorder - averaged value @xmath98 and the width @xmath87 of the distribution @xmath78 of the equilibrium barrier of eq . [ defgammaeq ] involve the barrier exponent @xmath99 @xmath100 of value @xmath101 these results are in agreement with scaling arguments on barriers @xcite and with the strong disorder renormalization approach of @xcite . over the disordered samples for the sherrington - kirkpatrick spin - glass model of @xmath8 spins ( @xmath102 configurations ) : ( a ) the log - log plot of the disorder - average @xmath103 as a function of @xmath8 for @xmath104 corresponds to the barrier exponent @xmath10 ( eq . [ psisk ] ) ( b ) the rescaled probability distribution @xmath105 of eq . [ defqrescaled ] , shown here for @xmath106 , in log scale to see the tail of eq . [ defeta ] : the tail exponent is of order @xmath14 . , title="fig:",height=226 ] over the disordered samples for the sherrington - kirkpatrick spin - glass model of @xmath8 spins ( @xmath102 configurations ) : ( a ) the log - log plot of the disorder - average @xmath103 as a function of @xmath8 for @xmath104 corresponds to the barrier exponent @xmath10 ( eq . [ psisk ] ) ( b ) the rescaled probability distribution @xmath105 of eq . [ defqrescaled ] , shown here for @xmath106 , in log scale to see the tail of eq . [ defeta ] : the tail exponent is of order @xmath14 . , title="fig:",height=226 ] as an example of application to a many - body disordered system , we consider in this section the of the sherrington - kirkpatrick spin - glass model where a configuration @xmath107 of @xmath8 spins @xmath108 has for energy @xcite @xmath109 where the couplings are random quenched variables of zero mean @xmath110 and of variance @xmath111 . the metropolis dynamics corresponds to the master equation of eq . [ master ] in configuration space with the transition rates @xmath112 where the factor @xmath113 means that the two configurations are related by a single spin flip . the data presented below correspond to the temperature @xmath114 . in the conjugate gradient described in section [ secconjugate ] , one can start from a random trial vector to begin the iterative method that will converge to the first excited eigenvector . however , in the case of spin models where @xmath115 is unchanged if one flips all the spins @xmath116 , one knows that the largest relaxation time will correspond to a global flip of all the spins . in terms of the quantum hamiltonian associated to the dynamics discussed in section [ secquantum ] , this means that the ground state @xmath117 of eq . [ psi0 ] is symmetric under a global flip of all the spins , whereas the first excited state @xmath118 is anti - symmetric under a global flip of all the spins . as a consequence , we have taken as initial trial eigenvector for the conjugate gradient method the vector @xmath119 defined as follows : denoting @xmath120 and @xmath121 the two opposite configurations where the ground state @xmath117 of eq . [ psi0 ] is maximal , one introduces the overlap between an arbitrary configuration @xmath31 and @xmath122 @xmath123 and the vector @xmath124 this vector is anti - symmetric under a global flip of all the spins and thus orthogonal to the ground state @xmath117 . moreover , it has already a small rayleigh quotient ( eq . [ rayleigh ] ) because within each valley where the sign of the overlap is fixed , it coincides up to a global sign with the ground state @xmath117 of zero energy . so the non - zero value of the rayleigh quotient of eq . [ rayleigh ] only comes from configurations of nearly zero overlap @xmath125 . as a consequence it is a good starting point for the conjugate gradient method to converge rapidly towards the true first excited state @xmath118 . we have studied systems of @xmath104 spins ( the space of configurations is of size @xmath102 ) , with a statistics of @xmath126 of independent disordered samples to compute the probability distribution @xmath127 of the largest barrier defined as @xmath128 as shown on fig . [ figsk](a ) , we find that the disorder averaged equilibrium barrier scales as @xmath129 this result is in agreement with theoretical predictions @xcite and with most previous numerical measures @xcite . it is also interesting to consider the sample - to - sample fluctuation exponent @xmath130 that governs the width of the probability distribution of the barrier @xmath131 although the disorder - average value has been much studied numerically @xcite , the only measure of @xmath130 we are aware of , is given by bittner and janke @xcite @xmath132 with our numerical data limited to small sizes @xmath104 , we see already the expected behavior of the disorder - average of eq . [ psisk ] as shown on fig . [ figsk ] ( a ) , but we are unfortunately not able to measure the exponent @xmath130 of eq . [ skwidth ] from the variance . however , as shown on fig . [ figsk](b ) , the probability distribution @xmath127 convergences rapidly towards a fixed rescaled distribution @xmath133 @xmath134 we find that the rescaled distribution @xmath135 presents at large argument the exponential decay @xmath136 with a tail exponent of order @xmath137 ( on fig . [ figsk](b ) , a straight line would correspond to @xmath138 . here we see a clear curvature indicating @xmath139 . the value of eq . [ etask ] has been estimated via a three - parameters fit @xmath140 for the data in the range @xmath141 ) . we are not aware of any theoretical prediction or any previous numerical measure of this tail exponent @xmath142 to compare with . however , it should have an interpretation in terms of rare events . if the tail is due to rare samples that occur with some exponentially small probability of order @xmath143 , but which present an anomalously large barrier of order @xmath144 , the consistency equation for the powers of @xmath8 in the exponentials read , using eqs [ defqrescaled ] and [ defeta ] @xmath145 we may now consider the contribution of various types of rare events : \(i ) the anomalously ferromagnetic samples correspond to @xmath146 ( with probability of order @xmath147 , the @xmath148 random variables @xmath149 will be all positive ) and to @xmath150 ( instead of being finite , the local field @xmath151 on spin @xmath152 will be of order @xmath153 ) . if @xmath154 , the corresponding tail exponent is @xmath155 which we have measured elsewhere @xcite for the case of the ferromagnetic sherrington - kirkpatrick model . since here we measure a significantly different value , we believe that the rare events dominating the tail for the spin - glass sherrington - kirkpatrick model are not these ferromagnetic rare samples . \(ii ) in a typical sample , the distribution @xmath156 of the local field extends down to @xmath157 , with the linear behavior @xmath158 as @xmath159 ) @xcite . however , with an exponentially small probability of order @xmath160 , the @xmath8 local fields of the sample will remain finite , i.e. bigger than some finite threshold @xmath161 , and the corresponding barrier will be anomalously large and of order @xmath8 . these rare samples , that have an anormalously strong spin - glass order , in the sense that all local fields remain finite , thus correspond to the values @xmath162 in eq . [ raresk ] . for instance , if @xmath154 , the corresponding tail exponent reads @xmath163 , whereas if @xmath164 , the corresponding tail exponent reads @xmath165 . our measure of eq . [ etask ] corresponds to @xmath166 a tentative conclusion would thus be the following : at the small sizes that we can study , we can not measure the width exponent @xmath167 from the variance , but we can measure the tail exponent @xmath142 that contains the information on @xmath130 if one can properly identify the rare events that dominate the tail . in the spin - glass phase considered here , we believe that the rare events dominating the tail are the rare samples described in ( ii ) that have an anormalously strong spin - glass order , in the sense that all local fields remain finite , so that our measure of the tail exponent of eq . [ etask ] would point towards the value of eq . [ psifrometa ] for the width exponent , which is actually very close to the value of eq . [ widthjanke ] measured by bittner and janke @xcite from the variance for large sizes @xmath8 . these two indications suggest that @xmath130 could actually be strictly smaller than the exponent @xmath10 governing the disorder - average value ( eq . [ psisk ] ) . to the best of our knowledge , this question has never been raised for the barrier statistics , but it has been much discussed for the statistics of the ground state energy in the sk model ( see @xcite and references therein ) , where the sample - to - sample exponent @xmath168 of the ground state energy ( or the finite temperature free energy ) is claimed to be either @xmath169 or @xmath170 , but is considered , in any case , to be smaller than the exponent @xmath171 that governs the correction to extensivity of the disorder average . a natural question is also whether the values @xmath10 and @xmath172 found in the statistics of the dynamical barrier are related to the exponents @xmath171 and @xmath168 that appear in the statistics of the ground state energy . in this paper , we have proposed to use the mapping between any master equation satisfying detailed balance and a schrdinger equation in configuration space to compute the largest relaxation time @xmath1 of the dynamics via lowest non - vanishing eigenvalue @xmath2 of the corresponding quantum hamiltonian @xmath0 ( the lowest eigenvalue being @xmath3 ) . this method allows to study the largest relaxation time @xmath1 _ without simulating the dynamics _ by any eigenvalue method able to compute the first excited energy @xmath4 . in the present paper , we have used the conjugate gradient method ( which is a simple iterative algorithm related to the lanczos method ) to study the statistics of the equilibrium time in two disordered systems : \(i ) for the random walk in a two - dimensional self - affine potential of hurst exponent @xmath0 \(ii ) for the dynamics of the sherrington - kirkpatrick spin - glass model of @xmath8 spins . the size of vectors used in the conjugate gradient method is the size @xmath173 of the configuration space for the dynamics : for instance it is @xmath174 for the case ( i ) of a single particle on the two - dimensional square @xmath5 and it is @xmath175 for ( ii ) containing @xmath8 classical spins . we have shown here that the conjugate gradient method was sufficient to measure the barrier exponents for these two models , but it is clear that it will not be sufficient for spin models in dimension @xmath176 or @xmath177 where the size of the configuration space grows as @xmath178 , and that it should be replaced by a quantum monte - carlo method to evaluate @xmath4 . for instance for the dynamics of the pure two dimensional ising model at criticality studied in @xcite , the conjugate - gradient method used for squares @xmath79 of sizes @xmath179 has been replaced for bigger sizes @xmath180 by a quantum monte - carlo method appropriate to compute excited states @xcite . we thus hope that the same strategy will be useful in the future to compute the equilibrium time of disordered spin models in dimension @xmath176 . it is a pleasure to thank a. billoire , j.p . bouchaud , a. bray and m. moore for discussion or correspondence on the statistics of dynamical barriers in mean - field spin - glasses . bouchaud , cond - mat/9910387 , published in soft and fragile matter : nonequilibrium dynamics , metastability and flow , m. e. cates and m. r. evans , eds . , iop publishing ( bristol and philadelphia ) 2000 , pp 285 - 304 l. berthier , v. viasnoff , o. white , v. orlyanchik , f. krzakala in `` slow relaxations and nonequilibrium dynamics in condensed matter '' ; eds : j .- barrat , j. dalibard , m. feigelman , j. kurchan ( springer , berlin , 2003 ) . r. paul , s. puri and h. rieger , eur . 68 , 881 ( 2004 ) ; r. paul , s. puri and h. rieger , phys . e 71 , 061109 ( 2005 ) ; h. rieger , g. schehr , r. paul , prog . 157 , 111 ( 2005 ) . w. krauth and o. pluchery , j. phys . a 27 ( 1994 ) l715 ; w. krauth , `` introduction to monte carlo algorithms '' in advances in computer simulation j. kertesz and i. kondor , eds , lecture notes in physics ( springer verlag , 1998 ) ; w. krauth , `` statistical mechanics : algorithms and computations '' , oxford university press ( 2006 ) . nightingale and h.w.j . blte , phys . 76 , 4548 ( 1996 ) ; m.p . nightingale and h.w.j . blte , phys . 80 , 1007 ( 1998 ) ; m.p . nightingale and h.w.j . blte , phys . b 62 , 1089 ( 2000 ) .

we consider the dynamics of finite - size disordered systems as defined by a master equation satisfying detailed balance . the master equation can be mapped onto a schrdinger equation in configuration space , where the quantum hamiltonian @xmath0 has the generic form of an anderson localization tight - binding model . the largest relaxation time @xmath1 governing the convergence towards boltzmann equilibrium is determined by the lowest non - vanishing eigenvalue @xmath2 of @xmath0 ( the lowest eigenvalue being @xmath3 ) . so the relaxation time @xmath1 can be computed _ without simulating the dynamics _ by any eigenvalue method able to compute the first excited energy @xmath4 . here we use the conjugate gradient method to determine @xmath4 in each disordered sample and present numerical results on the statistics of the relaxation time @xmath1 over the disordered samples of a given size for two models : ( i ) for the random walk in a self - affine potential of hurst exponent @xmath0 on a two - dimensional square of size @xmath5 , we find the activated scaling @xmath6 with @xmath7 as expected ; ( ii ) for the dynamics of the sherrington - kirkpatrick spin - glass model of @xmath8 spins , we find the growth @xmath9 with @xmath10 in agreement with most previous monte - carlo measures . in addition , we find that the rescaled distribution of @xmath11 decays as @xmath12 for large @xmath13 with a tail exponent of order @xmath14 . we give a rare - event interpretation of this value , that points towards a sample - to - sample fluctuation exponent of order @xmath15 for the barrier . # 1#2 # 1#2

ever since the discovery of terrestrial gamma ray flashes(tgfs ) about 20 years ago [ fishman et al . , 1994 ] , they have been known to be connected to thunderstorms . however , the predicted altitude of tgf production has changed significantly over the years , from more than 30 km [ fishman et al . , 1994 ] to less than 15 km [ dwyer et al . , 2012 ; tgfs are now expected to be produced within the thunderstorm . as the tropopause constitutes the upper limit for most clouds and the positive layer of a thundercloud can be expected to be close to the top of the thundercloud , the tropopause pressure distribution has been used as an approximation for the tgf production altitude distribution . some clouds with exceptionally strong updraft liu and zipser found that around 9000 deep convective systems were overshooting the tropopause , as defined in this paper , during 5 years . in the same years , lightning imaging sensor ( lis ) onboard the same satellite measured around 1.2 million thunderstorms . this means that around 0.8% of all thunderstorms within 35 latitude has overshooting clouds . even if the overshooting thunderstorms might have 24 times as many flashes as more shallow thunderstorms [ liu and zipser , 2005 ] , this indicate that only a small population of events are from overshooting clouds . the pressure and altitude of the tropopause are highly variable in both space and time . they varies with surface temperature , solar radiation , updrafts , and atmospheric water content . the general global pattern is a high tropopause in the tropics ( up to about 16 km altitude ) that becomes lower with increasing latitude ( around 8 km altitude at the poles ) . for a given location , the annual mean usually differs up to 0.5 km between years , while the monthly mean varies around 1 km over a year [ seidel and randel , 2006 ] . the day - to - day variability for a given location has a mean of 45 hpa or 1.4 km but can be as much as 2 km [ seidel and randel , 2006 ] . the altitude and pressure of the tropopause are important for establishing how much air the gamma rays have to go through to reach satellite altitude . furthermore , this can help us to estimate more precisely how many photons are produced in each tgf . the first measurements of tgfs were made by the burst and transient source experiment on board the compton gamma ray observatory [ fishman et al . , 1994 ] . later observations were made by the reuven ramaty high energy solar spectroscopic imager ( rhessi ) , the gamma - ray burst monitor on board the fermi gamma - ray space telescope and the astrorivelatore gamma a immagini leggero satellite [ dwyer et al . , 2012 ] . , and later , a new search algorithm for finding tgfs in the data set was developed by gjesteland et al . the new search algorithm found around 2500 tgfs compared to the 900 in the first catalog . this increase in numbers also give us a larger number of tgfs with a corresponding spheric match from the world wide lightning location network ( wwlln ) as described in gjesteland et al . , especially after 2007 when wwlln increased their detection efficiency [ collier et al . , 2011 ] . in this paper we first describe the method used to find the tropopause at the time and place of the tgfs and compare the method to the previous work by smith et al . . we will then compare the first and second catalog of rhessi tgfs . finally , we will use the tropopause distribution as an approximation of the tgf production altitude distribution and , when adjusting for the altitude and distance , estimate the fluence distribution at the source . carlson et al . addressed how the source fluence distribution looks like but only addressed the source distance from the satellite observation using a constant production altitude . this paper expand that work to also include the estimated relative altitude distribution of the tgf source . we used tropopause pressure data from the national centers for environmental prediction ( ncep)/national center for atmospheric research ( ncar ) 40 years reanalysis from noaa / earth system research laboratory ( esrl ) , an empirical model based on weather data kalnay et al . . the ncep / ncar reanalysis data are provided by the noaa / oar / esrl physical science division , boulder , colorado , usa , from their web site at http://www.esrl.noaa.gov / psd/. the reanalysis data provided are on a horizontal grid of 2.52.5 , and at several pressure levels including the tropopause level . the tropopause is defined by the standard definition from the world meteorological organization 's commission of aerology [ seidel and randel , 2006 ] , and the model provides the temperature and pressure at the tropopause . we chose to use the pressure as a measure of the tropopause altitude , as this enables us to directly find the amount of air above the tropopause . the ncep / ncar reanalysis has been found to give slightly too high tropopause pressures in the tropics . in an analysis by randel et al . they found a mean error of about 4 hpa with little or no seasonal dependence for 26 stations , while kaladis et al . found a small annual variability using only one station . the error is assumed to be related to how the satellite measurements are implemented into the model [ kaladis et al . , we use the tropopause pressure as provided by ncep / ncar . to improve the readability for readers not familiar with the use of pressure coordinates the conversion between pressure and altitude depends on several parameters including moisture and temperature of the air . in this paper , we use the standard atmosphere , and the altitudes are therefore only an approximate altitude . to find the position of the source lightning of tgfs , we use the world wide lightning location network ( wwlln ) . the wwlln matches for the tgfs are found using the same method as described in collier et al . . the search found 90 matches for the first catalog tgfs and 175 matches for the second catalog . the geographic distribution of the matches from the second catalog shows that the wwlln spherics often come from coastal areas as discussed in splitt et al . and briggs et al . . for lightning data we used the individual lightning detected in 2005 and 2006 by the lightning imaging sensor ( lis ) on board the tropical rainfall measuring mission . compared to wwlln , lis has a large and even detection efficiency within 35 latitude , making it suitable for statistical studies . the years 2005 and 2006 are by investigation seen to representing a typical period in terms of lightning density and geographical distribution and cover about one cycle of the quasi - biennial oscillation . in the ncep / ncar data the tropopause pressure is given for every 2.5 in latitude and longitude and for every 6 h interval throughout the year . when comparing rhessi tgfs with geolocated lightning it is found that most tgfs originate from within 400 km of the rhessi foot point [ hazelton et al . , 2009 ; collier et al . , 2011 ] , although other tgf measurements found 300 km to be the uniform boundary [ briggs et al . , 2013 ] . for the tgfs where we have wwlln matches , we use the point on the 2.52.5 grid that is closest to the geolocated lightning . for the other tgfs , we use the mean tropopause pressure within 400 km from the satellite foot point . an estimated error , based on a comparison between the mean and the closest point for the tgfs with geolocated lightning is found to be around 1.5 hpa . also used the ncep / ncar data to find the tropopause height , but they used the monthly mean for the point closest to the foot point . our method gives a wider pressure distribution , with significantly more tgfs at higher and at lower pressures . used monthly tropopause values and the closest point in space , whereas we use the mean pressure within 400 km around the satellite foot point ( closest point to the geolocated lightning where we have wwlln match ) and the closest time up to 3 h before or after the time of the tgfs . the figure demonstrates that our method gives a wider pressure distribution than smith et al . . in figure 2 , we show the difference between the tropopause pressure at the time of the tgfs and lightning compared to the normal tropopause pressure at the same place and time . the normal pressure used is the mean over 20 years for the place and time of year of the tgfs provided by the ncep / ncar reanalysis . the figure shows that lightning and tgfs mainly occur when the tropopause pressure is about normal . all differences larger than 20 and + 10 hpa are from tgfs and lightning occurring at latitudes higher ( lower ) than + ( ) 20 latitude . the normal pressure is taken from the 20 year mean values of the ncep / ncar reanalysis . the tropopause pressure when lightning occurs is slightly lower than the normal pressure at the same place and time of year , while the pressure at the time and place of tgfs are approximately centered around the normal pressure . in the tropics , the tropopause pressure is shown to have an annual pattern with relatively higher pressures in june - july - august ( jja ) than in december - january - february ( djf ) [ reid and gage , 1996 ] . this variation is due to a stronger brewer - dobson circulation in the north subtropics winter ( djf ) than in the south subtropics winter ( jja ) , due to more land masses in the north and the topography of these land masses [ fueglistaler et al . , since lightning and tgfs mainly happen in local summer , this means that most tgfs in the north will occur in the months when the tropopause pressure is relatively higher ( jja ) , and the tgfs in the south will occur when the tropopause pressure is relatively lower ( djf ) . the tropopause pressure for the time and place of tgfs is shown in figure 3 , which demonstrates that the tropopause pressure for tgfs in jja is 1015 hpa higher than in djf between 20 and 20 latitude . if this pressure perturbation extends down to the source region for tgfs , it means that we can expect the measured tgf - to - lightning ratio to be smaller in summer ( jja ) than in winter ( djf ) , due to an easier escape of the gamma rays from the atmosphere during december , january , and february . unfortunately , the rhessi statistics are not large enough for this to be investigated in the tgf data as enough tgfs in a relatively uniform geographical region is needed . a comparison of mean tropopause pressures at the time and place of tgfs between june - july - august and in december - january - february binned by latitude . the lower pressure in djf is due to a stronger dobson - brewer circulation in these months . a comparison between the tropopause pressure of the tgfs in the first rhessi catalog [ grefenstette et al . , 2009 ] and the tgfs from the second catalog [ gjesteland et al . , the figure demonstrates that the two distributions are quite similar , the main difference being between 125 hpa and 145 hpa where catalog 2 has a relatively larger number of events than catalog 1 . the error bars are calculated using the square root of the number of events in each bin . the second catalog tgfs are mainly following the same pattern as the tgfs of the first catalog , but with a relatively larger portion of tgfs coming from times and locations where the pressure is between 125 hpa and 145 hpa . figure 5 presents the distance between the wwlln - located spherics and the rhessi foot point for the 265 tgfs having a wwlln match . the figure shows that a relatively larger number of the second catalog tgfs originates from distances between 400 and 500 km from satellite foot point than the tgfs in the first catalog . the catalog 2 tgfs that are seen to come from close distances might either be in the lower end of a power law distribution as indicated by stgaard et al . or be equally strong tgfs originating from further below the tropopause . the distance between the wwlln detected spheric and the rhessi foot - point for the first and the second catalog tgfs . this figure shows that a relatively larger number of the catalog 2 tgfs arrive from distances between 400 and 500 km from rhessi than the tgfs from catalog 1 . the transmission of gamma rays in air decreases exponentially with increasing density , and the density of the atmosphere increases exponentially downward . this means that by increasing the sensitivity of rhessi ( as is done in catalog 2 ) , it is easier to see more tgfs at larger distances than deeper in the cloud . we used the time and position of the individual lightnings registered by lis in 2005 and 2006 and found the tropopause pressure of the closest point in space and time in the ncep / ncar data . also plotted are the tropopause pressures for lightning of figure 9 ( black curve ) of smith et al . . smith et al . were using a monthly map of lightning density and the monthly mean value for the tropopause pressure . it is apparent that our method gives relatively larger portion of lightning at lower tropopause pressure and slightly more spread in tropopause pressure . difference in tropopause pressure at the time of lightning between the method of smith et al . and our method . the tropopause pressures are directly related to the transmission of gamma rays from the tropopause up to satellite altitude . we used the monte carlo simulations described in stgaard et al . to find that the number of photons escaping the atmosphere is proportional to , where tot is the total mass the photons are traveling through in g / cm . this is the same relation as found by smith et al . and will be used to find the relative transmission coefficients for gamma rays from lightning to escape the atmosphere . to make a comparison with the results of smith et al . , we made a similar geographical presentation of the difference between the transmission - corrected lightning map and the tgf map as figure 5d of smith et al . . the transmission - corrected lightning map was made by summing the transmission coefficients corresponding to each individual lightning in the lis data from 2005 and 2006 over 2.52.5 bins divided by the total number of lightning and folded this with the lis exposure map ( sinus curve with maximum latitude of 35 ) and the efficiency map of rhessi made from the particle measurement map from hell and bamberg ( figure 2.1 ) and the exposure map of rhessi ( sinus curve with maximum latitude of 38 ) . as we only use relative numbers , we use arbitrary units ; the values on the scale are arbitrary units . since our tropopause pressure is generally slightly lower than the tropopause from smith et al . , our probability of transmission will be higher ; but because the shape of the two curves in figure 6 is about the same , the relative difference will be fairly similar . in figure 7 , we show the difference between the first rhessi catalog tgfs and the expected relative difference estimated from the lightning data , the exposure / efficiency and transmission . the map shows the same features as in figure 5d of smith et al . , with the main discrepancies being the greater lack of tgfs in northern india and less negative values in africa . the figure shows a similar global pattern as the inverse flash rate , duration , and radiance of lis [ beirle et al . , 2014 ] the difference between the expected number of tgfs and the measured tgfs from the first rhessi catalog . the blue colors denote a lesser amount of tgfs than expected , and the red colors denote a bigger amount of tgfs than expected . the figure reveals a lack of tgfs in africa compared to the expected and an excess of tgfs in asia and america . in figure 8 , we present the relative difference between the second rhessi catalog tgfs and the expected relative difference between continents . this shows little or no significant difference from the first catalog tgfs , which is as expected due to the close relation in geographic distributions between the first and the second catalog of tgfs as seen in gjesteland et al . . the difference between the estimated relative expected number of tgfs and the measured tgfs from the second rhessi catalog . the blue colors denote a lesser amount of tgfs than expected , and the red colors denote a bigger amount of tgfs than expected . the second rhessi catalog shows the same pattern as the first catalog . for the tgfs with wwlln matches we know the distance from the lightning to rhessi and the tropopause height , and we will use that to estimate the strength of the tgfs at the source using the tropopause distribution as the approximation for tgf production altitude . the source fluence can be estimated by where nrhessi is the dead time - corrected number of photons measured by rhessi , r is the distance between the wwlln spheric and rhessi , is the vertical mass above the tropopause , is the angle of r to the vertical , and c is a constant . the value of the constant c is dependent on the minimum number of photons needed to get a detection in the instrument , the number of photons lost in the detector , and if the instrument is inside or outside of the initial source cone of the tgf photons . figure 3 shows a difference in the number of a factor 2 between observations made inside and outside the initial cone of the tgf photons even when accounting for the r and cos( ) effect . with an angular distribution of around 40 , we have adjusted for the angular dependence by using c for < 40 and 2*c for > 40 . to get the numbers of 10 and 10 as given in literature [ hansen et al . , 2013 ; dwyer et al . , 2012 ] , the value is of the order of 10 . the dead time - corrected fluence distribution for rhessi of tgfs with wwlln matches is shown in red in figure 9 . although the distribution in figure 9 is quite similar to what was found by stgaard et al . and tierney et al . , a direct comparison can not be made for the following reasons : the tgfs used in stgaard et al . are only the tgfs observed by rhessi before the degradation of the instrument in 20052006 , while we use the tgfs measurements made up until to 2011 . as the strong tgfs from after 2005 are mixed with the weaker tgfs from before 2005 , this causes a softer distribution which becomes apparent when using all our tgfs . that the tgfs with wwlln matches are comparable to the pre-2005 distribution which is due to wwlln having higher sensitivity to strong tgfs [ collier et al . , the power law index found in this study can not be directly compared to the power law index found in the previous studies , but the change in fluence distribution can be expected to be comparable to the actual change . fluence distribution of dead time - corrected rhessi measurements with wwlln matches and the altitude - corrected fluence distribution as calculated from equation 1 , including the best fit power law for the two distributions . the pressure - corrected distribution has a slightly lower power law index than the not pressure - adjusted distribution . the black curve and line in figure 9 are the distance and pressure - corrected fluence distribution as calculated from equation 1 and the corresponding power law . the best fit power law for the two distributions is 2.60.1 without pressure correction and 3.20.1 for the pressure - corrected tgfs . the error interval is defined so that all power law indexes with a p value larger than 0.05 are within the error bars . this shows that the distribution changes slightly to a softer distribution when the altitude is accounted for . carlson et al . did a comparison of the source strength and the observed fluence distributions without accounting for the different altitude distributions . analysis and demonstrate that the altitude distribution has to be considered when investigating the source fluence distribution . we have shown that the tgfs of the second rhessi catalog originate from the same altitudes as the tgfs of the first catalog , but that a bigger portion of tgfs comes from larger horizontal distances . aside from this , the second catalog confirms the main findings of smith et al . . we find that the tropopause at the time and place of tgfs is consistent with the predictions of the brewer - dobson circulation that the southern summer ( djf ) will have a systematically lower tropopause pressure than the northern summer ( jja ) , and therefore , a higher fraction of tgf photons will escape the atmosphere during djf . based on this , we predict that the ratio of measured tgfs to lightning can be expected to have an annual variation . the main finding of this study , however , lies in the discovery that the source fluence distribution is slightly softer when the altitude distribution of tgfs is accounted for . the fluence distribution for tgfs is softer when the altitude is accounted for the ratio of tgfs to lightning can be expected to have an annual variability the second rhessi tgf catalog confirms the main findings of the first catalog

the source fluence distribution of terrestrial gamma ray flashes ( tgfs ) has been extensively discussed in recent years , but few have considered how the tgf fluence distribution at the source , as estimated from satellite measurements , depends on the distance from satellite foot point and assumed production altitude . as the absorption of the tgf photons increases significantly with lower source altitude and larger distance between the source and the observing satellite , these might be important factors . we have addressed the issue by using the tropopause pressure distribution as an approximation of the tgf production altitude distribution and world wide lightning location network spheric measurements to determine the distance . the study is made possible by the increased number of ramaty high energy solar spectroscopic imager ( rhessi ) tgfs found in the second catalog of the rhessi data . one find is that the tgf / lightning ratio for the tropics probably has an annual variability due to an annual variability in the dobson - brewer circulation . the main result is an indication that the altitude distribution and distance should be considered when investigating the source fluence distribution of tgfs , as this leads to a softening of the inferred distribution of source brightness .

TITLE I--AMENDMENTS TO TITLE 11 OF THE UNITED STATES CODE SEC 101. SHORT TITLE. This title may be cited as the ``Spousal Equity in Bankruptcy Amendments of 1994''. SEC. 102. AMENDMENTS. (a) Relief From Automatic Stay.--Section 362(b)(2) of title 11, United States Code, is amended to read as follows: ``(2) under subsection (a) of this section-- ``(A) of the commencement or continuation of an action or proceeding for-- ``(i) the establishment of paternity; or ``(ii) the establishment or modification of an order for alimony, maintenance, or support; or ``(B) of the collection of alimony, maintenance, or support from property that is not property of the estate;''. (b) Priority of Claims.--(1) Section 507 of title 11, United States Code, is amended-- (A) in subsection (a)-- (i) in paragraph (8) by striking ``(8) Eighth'' and inserting ``(9) Ninth'', (ii) in paragraph (7) by striking ``(7) Seventh'' and inserting ``(8) Eighth'', and (iii) by inserting after paragraph (6) the following: ``(7) Seventh, allowed unsecured claims due to a spouse, former spouse, or child of the debtor for alimony to, maintenance for, or support of such spouse or child, in connection with a separation agreement, divorce decree, or other order of a court of record, a determination made in accordance with State or territorial law by a governmental unit, or a property settlement agreement, but not to the extent that-- ``(A) such debt is assigned to another entity, voluntarily, by operation of law, or otherwise (other than debts assigned pursuant to section 402(a)(26) of the Social Security Act, or any such debt which has been assigned to the Federal Government or to a State or any political subdivision of such State); or ``(B) such debt includes a liability designated as alimony, maintenance, or support, unless such liability is actually in the nature of alimony, maintenance or support;'', and (B) in subsection (d) by striking ``or (6)'' and inserting ``(6), or (7)''. (2) Title 11 of the United States Code is amended-- (A) in sections 502(i), 503(b)(1)(B)(i), 523(a)(1)(A), and 1123(a)(1) by striking ``507(a)(7)'' and inserting ``507(a)(8)'', (B) in section 724(b)(2) by striking ``or 507(a)(6)'' and inserting ``507(a)(6), or 507(a)(7)'', (C) in section 726(b) by striking ``or (7)'' and inserting ``, (7), or (8)'', and (D) in section 1129(a)(9)-- (i) in subparagraph (B) by striking ``or 507(a)(6)'' and inserting ``, 507(a)(6), or 507(a)(7)'', and (ii) in subparagraph (C) by striking ``507(a)(7)'' and inserting ``507(a)(8)''. (c) Protection of Liens.--Section 522(f)(1) of title 11, United States Code, is amended to read as follows: ``(1) a judicial lien (other than a judicial lien that secures a debt to a spouse, former spouse, or child of the debtor, for alimony to, maintenance for, or support of the spouse or child, in connection with a separation agreement, divorce decree or other order of a court of record, determination made in accordance with State or territorial law by a governmental unit, or property settlement agreement, to the extent that the debt-- ``(A) is not assigned to another entity, voluntarily, by operation of law, or otherwise; and ``(B) includes a liability designated as alimony, maintenance, or support, unless such liability is actually in the nature of alimony, maintenance or support).''. (d) Exception to Discharge.--Section 523 of title 11, United States Code, is amended-- (1) in subsection (a)-- (A) in paragraph (11) by striking ``or'' at the end, (B) in paragraph (12) by inserting ``or'' after the semicolon at the end, and (C) by adding at the end the following: ``(13) assumed or incurred by the debtor in the course of a divorce or separation or in connection with a separation agreement, divorce decree or other order of a court of record, a determination made in accordance with State or territorial law by a governmental unit, or property settlement agreement, unless-- ``(A) excepting such debt from discharge under this paragraph would impose an undue hardship for the debtor; and ``(B) discharging such debt would result in a benefit to the debtor that outweighs the detrimental consequences to a spouse, former spouse, or child of the debtor.'', and (2) in subsection (c)(1) by striking ``or (6)'' each place it appears and inserting ``, or (13)''. (e) Protection Against Trustee Avoidance.--Section 547(c) of title 11, United States Code, is amended-- (1) by striking ``or'' at the end of paragraph (6); (2) by redesignating paragraph (7) as paragraph (8); and (3) by inserting after paragraph (6) the following new paragraph: ``(7) to the extent that the transfer was a bona fide payment of a debt to a spouse, former spouse, or child of the debtor, for alimony to, maintenance for, or support of such spouse or child, in connection with a separation agreement, divorce decree or other order of a court of record, determination made in accordance with State or territorial law by a governmental unit, or property settlement agreement, but not to the extent that such debt-- ``(A) is assigned to another entity, voluntarily, by operation of law, or otherwise; or ``(B) includes a liability designated as alimony, maintenance, or support, unless such liability is actually in the nature of alimony, maintenance or support; or''. (f) Appearance Before Court.--A child support creditor or its representative shall be permitted to appear and intervene without charge and without meeting any special local court rule requirement for attorney appearances in any bankruptcy proceeding in any bankruptcy court or district court of the United States if the creditor or representative files with the court a statement describing in detail the child support debt, its status, and other characteristics. TITLE II--BANKRUPTCY REVIEW COMMISSION SEC. 201. SHORT TITLE. This title may be cited as the ``National Bankruptcy Review Commission Act''. SEC. 202. ESTABLISHMENT. There is established the National Bankruptcy Review Commission (referred to as the ``Commission''). SEC. 203. DUTIES OF THE COMMISSION. The duties of the Commission are-- (1) to investigate and study issues and problems relating to title 11, United States Code (commonly known as the ``Bankruptcy Code''); (2) to evaluate the advisability of proposals and current arrangements with respect to such issues and problems; (3) to prepare and submit to the Congress, the Chief Justice, and the President a report in accordance with section 208; (4) to solicit divergent views of all parties concerned with the operation of the bankruptcy system; and (5) to study the impact of the bankruptcy laws on the family and particularly on the increase in the number of women and children living in poverty after divorce. SEC. 204. MEMBERSHIP. (a) Number and Appointment.--The Commission shall be composed of 10 members appointed from among individuals who have experience and expertise in bankruptcy law as follows: (1) Four members appointed by the President, one of whom shall be designated as chairman by the President. (2) One member shall be appointed by the President pro tempore of the Senate. (3) One member shall be appointed by the Minority Leader of the Senate. (4) One member shall be appointed by the Speaker of the House of Representatives. (5) One member shall be appointed by the Minority Leader of the House of Representatives. (6) Two members appointed by the Chief Justice. (b) Term.--Members of the Commission shall be appointed for the life of the Commission. (c) Quorum.--Six members of the Commission shall constitute a quorum, but a lesser number may conduct meetings. (d) Appointment Deadline.--The first appointments made under subsection (a) shall be made within 60 days after the date of enactment of this Act. (e) First Meeting.--The first meeting of the Commission shall be called by the chairman and shall be held within 90 days after the date of enactment of this Act. (f) Vacancy.--A vacancy on the Commission resulting from the death or resignation of a member shall not affect its powers and shall be filled in the same manner in which the original appointment was made. (g) Continuation of Membership.--If any member of the Commission who was appointed to the Commission as a member of Congress or as an officer or employee of a government leaves that office, or if any member of the Commission who was not appointed in such a capacity becomes an officer or employee of a government, the member may continue as a member of the Commission for not longer than the 90-day period beginning on the date the member leaves that office or becomes such an officer or employee, as the case may be. (h) Consultation Prior to Appointment.--Prior to the appointment of members of the Commission, the President, the President pro tempore of the Senate, the Speaker of the House of Representatives, and the Chief Justice shall consult with each other to ensure fair and equitable representation of various points of view in the Commission and its staff. SEC. 205. COMPENSATION OF THE COMMISSION. (a) Pay.-- (1) Nongovernment employees.--Each member of the Commission who is not otherwise employed by the United States Government shall be entitled to receive the daily equivalent of the annual rate of basic pay payable for level IV of the Executive Schedule under section 5315 of title 5, United States Code, for each day (including travel time) during which he or she is engaged in the actual performance of duties as a member of the Commission. (2) Government employees.--A member of the Commission who is an officer or employee of the United States Government shall serve without additional compensation. (b) Travel.--Members of the Commission shall be reimbursed for travel, subsistence, and other necessary expenses incurred by them in the performance of their duties. SEC. 206. STAFF OF COMMISSION; EXPERTS AND CONSULTANTS. (a) Staff.-- (1) Appointment.--The chairman of the Commission may, without regard to the civil service laws and regulations, appoint, and terminate an executive director and such other personnel as are necessary to enable the Commission to perform its duties. The employment of an executive director shall be subject to confirmation by the Commission. (2) Compensation.--The chairman of the Commission may fix the compensation of the executive director and other personnel without regard to the provisions of chapter 51 and subchapter II of chapter 53 of title 5, United States Code, relating to classification of positions and General Schedule pay rates, except that the rate of pay for the executive director and other personnel may not exceed the rate payable for level V of the Executive Schedule under section 5316 of that title. (b) Experts and Consultants.--The Commission may procure temporary and intermittent services of experts and consultants under section 3109(b) of title 5, United States Code. SEC. 207. POWERS OF THE COMMISSION. (a) Hearings and Meetings.--The Commission or, on authorization of the Commission, a member of the Commission, may hold such hearings, sit and act at such time and places, take such testimony, and receive such evidence, as the Commission considers appropriate. The Commission or a member of the Commission may administer oaths or affirmations to witnesses appearing before it. (b) Official Data.--The Commission may secure directly from any Federal department, agency, or court information necessary to enable it to carry out this title. Upon request of the chairman of the Commission, the head of a Federal department or agency or chief judge of a Federal court shall furnish such information, consistent with law, to the Commission. (c) Facilities and Support Services.--The Administrator of General Services shall provide to the Commission on a reimbursable basis such facilities and support services as the Commission may request. Upon request of the Commission, the head of a Federal department or agency may make any of the facilities or services of the agency available to the Commission to assist the Commission in carrying out its duties under this title. (d) Expenditures and Contracts.--The Commission or, on authorization of the Commission, a member of the Commission may make expenditures and enter into contracts for the procurement of such supplies, services, and property as the Commission or member considers appropriate for the purposes of carrying out the duties of the Commission. Such expenditures and contracts may be made only to such extent or in such amounts as are provided in appropriation Acts. (e) Mails.--The Commission may use the United States mails in the same manner and under the same conditions as other Federal departments and agencies of the United States. (f) Gifts.--The Commission may accept, use, and dispose of gifts or donations of services or property. SEC. 208. REPORT. The Commission shall submit to the Congress, the Chief Justice, and the President a report not later than 2 years after the date of its first meeting. The report shall contain a detailed statement of the findings and conclusions of the Commission, together with its recommendations for such legislative or administrative action as it considers appropriate. SEC. 209. TERMINATION. The Commission shall cease to exist on the date that is 30 days after the date on which it submits its report under section 208. SEC. 410. AUTHORIZATION OF APPROPRIATIONS. There is authorized to be appropriated $1,500,000 to carry out this title. HR 4711 IH----2

TABLE OF CONTENTS: Title I: Amendments to Title 11 of the United States Code Title II: Bankruptcy Review Commission Title I: Amendments to Title 11 of the United States Code - Spousal Equity in Bankruptcy Amendments of 1994 - Amends Federal bankruptcy law to provide that filing a petition in bankruptcy does not operate as an automatic stay from actions for: (1) paternity; or (2) alimony, maintenance, or support (including actions for collection from property that is not property of the estate). Includes unsecured claims for alimony, maintenance, or support among priority claims and expenses (thus lifting them from their current status of general, unsecured debts). Prohibits a debtor from avoiding a judicial lien that secures a debt for alimony, maintenance, or support. States that a bankrupt debtor is not discharged from any debt incurred in connection with a divorce or separation agreement. Prohibits a bankruptcy trustee from avoiding a transfer that is a bona fide debt for alimony, maintenance, or support. Permits a child support creditor to appear before the court in any Federal bankruptcy proceeding without charge and without meeting local requirements for attorney appearances if the creditor or representative files a detailed child support debt statement. Title II: Bankruptcy Review Commission - National Bankruptcy Review Commission Act - Establishes the National Bankruptcy Review Commission to study and report to the Congress, the Chief Justice, and the President on bankruptcy issues and the impact of the bankruptcy laws upon women and children living in poverty after divorce. Authorizes appropriations.

the discovery of hundreds of ultra low - mass dwarfs and substellar objects by the 2 micron all sky survey ( 2mass ) , the deep near infrared southern sky survey ( denis ) and the sloan digital sky survey ( sdss ) has provided a large data base from which to select l and t dwarfs for further study . the l dwarfs identified by these surveys have been classified using far optical ( @xmath6 0.6 - 1.0 @xmath7 ) spectroscopy and most have published _ j _ ( 1.1 - 1.4 @xmath7 ) , _ h _ ( 1.5 - 1.8 @xmath7 ) and _ k _ band ( 2.0 - 2.4 @xmath7 ) magnitudes @xcite . in addition several groups have used near - infrared spectroscopy from 1 to 2.5 @xmath7 to classify and study l dwarfs @xcite . comparatively , little work has been done beyond 2.5 @xmath7 , where to date only six l dwarfs have published _ l_-band magnitudes @xcite . since brown dwarfs emit most of their flux in the near infrared , observations beyond 2.5 @xmath7 are useful to the determination of the bolometric luminosity of these objects . in addition water ( @xmath0 ) , carbon monoxide ( co ) , and methane ( @xmath1 ) which are among the most abundant atmospheric species after hydrogen ( h@xmath8 ) are important opacity sources at these wavelengths . indeed @xmath0 and @xmath1 opacities dominate the _ l_-band ( 2.5 - 4.1 @xmath7 ) radiative transfer . in particular the @xmath4 band ( 2.5 - 3.5 @xmath7 ) overlaps the strong @xmath9 fundamental band of @xmath1 at 3.3 @xmath7 , which is observable in some of the late l dwarfs and all of the t dwarfs @xcite . because chemical equilibrium favors @xmath1 over co with falling atmospheric temperature @xcite , the abundance of @xmath1 helps to constrain the effective temperature ( @xmath10 ) . in the _ l@xmath3 _ band ( 3.5 - 4.1 @xmath7 ) @xmath0 alone is the dominant opacity source . atmosphere models @xcite suggest that the ( _ k - l@xmath3 _ ) color of l dwarfs is relatively insensitive to the details of cloud models , or even the absence of clouds , making this color a potentially interesting diagnostic of @xmath10 . when used together , the @xmath4 and _ l@xmath3 _ bands can probe for the appearance of @xmath1 in the latest l dwarfs , identify for trends in color which are a function of spectral type and temperature , and provide flux measurements for use in estimating the bolometric luminosity of these objects . here we report _ l_-band observations for a sample of l and t dwarfs , their observed trends , and comment on the l - dwarf @xmath10 scale . the data were acquired using the near infrared camera , nirc @xcite on keck i at the w.m . keck observatory located in mauna kea , hawaii on april 13th and 14th , ut 2000 . photometry was obtained using _ k _ , @xmath11 , @xmath4 , _ l@xmath3 _ and a 3.3 @xmath7 narrow band filter for 18 l dwarfs and 5 t dwarfs which were observable at a low airmass , and chosen to span the l - dwarf spectral sequence . where multiple objects of a given spectral type were available to observe , preference was given to those objects which were most typical in their ( _ j - k _ ) and ( _ h - k _ ) colors respective to spectral type @xcite . the resulting data set includes objects with spectral types ranging from l0 to l8 in the @xcite classification as well as five t dwarfs ranging from t0 to t6 in the a. burgasser ( 2001 , private communication ) classification . table 1 lists the targets , their coordinates , observed magnitudes and colors . both nights were photometric with seeing ranging between 0.35and 0.6 . since the radiation background from the sky is considerably larger at 3 @xmath7 and beyond , integration times were limited to 0.012 and 0.03 seconds in the _ l@xmath3 _ and @xmath4 bands . to achieve these integration times , a 64 @xmath12 64 subsection of the chip was read out using the pat4xa timing pattern . standard chopping and nodding procedures were also employed to minimize errors resulting from temporal variations in the sky radiation background . to place our photometry onto a standard infrared photometric system , standard stars were chosen from the ukirt fundamental and extended list @xcite and were observed at the same airmass directly before or after the target objects . in the case where a ukirt standard of the same airmass was not available to observe , standard stars were then chosen from the @xcite nicmos standard list and their magnitudes were converted to the ukirt system using the formula given by @xcite . these lists provided standard _ k_-band magnitudes , but not _ l@xmath3 _ or @xmath4 magnitudes . to determine a standard magnitude for our _ l_-band observations we observed only main sequence standard stars with spectral types between a0v and g6v , and estimated a standard _ l@xmath3 _ or @xmath4 magnitude for each star using the intrinsic colors given by @xcite for a main sequence star of that spectral type . since the ( _ k - l@xmath3 _ ) and ( _ k - l _ ) values of these stars vary between 0.0 for a0v to 0.05 for g6v , we estimate that this technique produces no more than a 5% error in our magnitude calculation and this error has been included in the final _ l@xmath3 _ and @xmath4 magnitude tabulation ( table 1 ) . as an additional check standard stars that deviated largely from the mean _ l@xmath3 _ and @xmath4 zeropoint correction determined from all of the standard stars were discarded . this resulted in the elimination of no more than one standard star each night and we are confident that this technique produces valid _ l@xmath3 _ and @xmath4 magnitudes for our objects . the standard stars used to calibrate the photometry in table 1 are on the ukirt ircam3 natural system . convolutions of the filter transmission profiles for the nirc and ircam3 filters with model spectra reveals a constant zeropoint offset between the two systems with no dependence on spectral type . thus the photometry presented in this paper is on the ukirt ircam3 system . it is important to note that this is not the same photometric system as the mauna kea observatory near - infrared system ( mko - nir ) . while the _ k _ band magnitudes for our l dwarfs can be placed on the mko - nir system using the transformation equations provided by @xcite , there is not a conversion equation for the _ l@xmath3 _ magnitudes . a comparison of the _ l@xmath3 _ filters for both the nirc and mko - nir systems reveals that the mko - nir filter extends farther into the blue from 3.4 to 4.1 @xmath7 while the nirc filter only extends from 3.5 to 4.1 @xmath7 . this results in the mko - nir filter being more sensitive to the appearance of @xmath1 absorption at 3.3 @xmath7 . the net effect is that for the hottest l dwarfs , our _ l@xmath3 _ magnitudes are almost identical to the mko - nir magnitudes . for the latest l dwarfs where @xmath1 is just beginning to affect the spectrum , our _ l@xmath3 _ magnitudes are 10% brighter , and for the t dwarfs where @xmath1 absorption is strongly established , our _ l@xmath3 _ magnitudes are 20% brighter ( differences of 0.1 and 0.2 mag respectively ) . thus any comparison of the _ l@xmath3 _ magnitudes from these two systems needs to take this offset into account . as a final comment on the magnitudes presented here , we need to mention that although observations were acquired using both the _ k _ and @xmath11 filters , we found that in general the _ k_-band magnitude differed from the @xmath11-band magnitude by no more than 0.05 for the l dwarfs and 0.1 for the t dwarfs . in addition since transformation equations from the ukirt ircam3 system to the other standard infrared systems use the ukirt _ k_-band magnitudes for conversion and not @xmath11 , we present only the _ k_-band magnitudes . figure 1 presents the ( _ k - l@xmath3 _ ) color of our objects as a function of l- and t - dwarf spectral class . the closed squares represent the objects from table 1 , and the open circles represent ( _ k - l@xmath3 _ ) colors for six l dwarfs by @xcite . in general the ( _ k - l@xmath3 _ ) color gradually increases with later l- and t - dwarf spectral type . a linear least squares fit of the data to the l dwarf index shows that the ( _ k - l@xmath3 _ ) colors are reasonably well fit ( correlation coefficient , @xmath13 ) by a line with a slope of 0.092 and an intercept point of 0.87 . for l dwarfs the increase in ( _ k - l@xmath3 _ ) color is due to increasing molecular absorption in the _ k _ band . as the @xmath10 decreases with later spectral type , the wings of the @xmath0 band at 1.9 @xmath7 and pressure induced @xmath14-@xmath14 absorption together suppress the _ k_-band flux . in the _ l@xmath3 _ band the principle opacity source is @xmath0 alone . as the temperature decreases , the mean opacity increases more slowly in the _ l@xmath3 _ band than in the _ k _ band . the net result is that the total flux emitted in the _ k _ band falls faster than the total flux emitted in the _ l@xmath3 _ band with decreasing temperature . this produces the redder ( _ k - l@xmath3 _ ) colors with later l - dwarf spectral type . a similar mechanism is responsible for the gradual reddening of the t dwarfs . for these objects @xmath1 joins @xmath0 and @xmath14-@xmath14 as the principle opacity sources . by definition , the transition from the l to t dwarfs occurs when the @xmath15 combination band of @xmath1 first appears at 2.2 @xmath7 @xcite . a linear least squares fit ( @xmath16 ) of the t dwarf data produces a slightly steeper line with a slope of 0.161 and an intercept point of -0.19 . the change in slope from the l to t dwarfs suggests that the additional appearance of @xmath1 opacity further suppresses the flux in the _ k _ band , resulting in a steeper ( _ k - l@xmath3 _ ) color increase throughout the t dwarfs . since the abundance of @xmath1 varies with @xmath10 and it is the dominant opacity source for t dwarfs at _ k _ band , but not _ l@xmath3 _ , the ( _ k - l@xmath3 _ ) color should prove to be a good diagnostic for estimating the @xmath10 of t dwarfs . figure 2 presents the ( _ k_-@xmath4 ) color of our objects as a function of l- and t - dwarf spectral class . like the ( _ k - l@xmath3 _ ) color , the increase in ( _ k_-@xmath4 ) through the l - dwarf spectral sequence is due to increasing @xmath0 and @xmath14-@xmath14 absorption in the _ k _ band . a linear least squares fit applied to this data ( @xmath17 ) produces a line with a slope of 0.06 and an intercept point of 0.14 . it is interesting to note that there appears to be substantially more scatter in the ( _ k_-@xmath4 ) color for the later l dwarfs ( and early t dwarfs ) as compared to the early l dwarfs . this scatter may arise from differences in cloud cover @xcite , or possibly atmospheric dynamics or metallicity producing greater variability in @xmath1 abundance in these objects . for the t dwarfs @xmath1 absorption definitely occurs both at 3.3 @xmath7 and 2.2 @xmath7 which results in a suppression of the flux in the @xmath4 and _ k _ bands . since the @xmath9 fundamental band of @xmath1 at 3.3 @xmath7 is a factor of 100 times stronger than the @xmath15 combination band at 2.2 @xmath7 , there is a greater suppression of the flux in the @xmath4 band than in the _ k _ band which results in a bluer color for the t dwarfs . if @xmath1 absorption were to gradually appear in the latest l dwarfs with falling @xmath10 , we would expect the ( _ k_-@xmath4 ) color of the late l dwarfs to gradually transition into the bluer color of the early t dwarfs . however , the abrupt transition in ( _ k_-@xmath4 ) from the latest l dwarfs to the earliest t dwarfs suggests that perhaps very early t dwarfs , or very late l dwarfs have yet to be discovered , or that substantial @xmath4 band @xmath1 absorption appears rapidly over a very small @xmath10 range . note that the two l1 dwarfs both have very blue ( _ k_-@xmath4 ) colors , but unexceptional ( _ k - l@xmath3 _ ) colors . these two objects were also unusually faint in narrow band 3.3 @xmath7 ( nirc pahl filter ) images obtained the same night . this suggests that another opacity source is affecting the flux in the @xmath4 band for these two objects . clearly 3 to 4 @xmath7 spectroscopy is needed to constrain what is suppressing the flux in the @xmath4 band . we are confident that the colors of the l1 dwarfs are not due to photometric errors since these objects were observed at different times during the night and with different standard stars . one of the l1 dwarfs , denis j1441 - 0945 , is a binary system and if the two components of the system have different @xmath4 magnitudes this may be the cause of the color discrepancy . indeed it does appear that the pair is of unequal brightness although they are too close for individual photometry . however this would imply that the other l1 dwarf is also a binary system and we see no evidence of multiplicity in our 0.5images of 2massw j1035 + 2507 . finally figure 3 presents a ( _ k_-@xmath4 ) verses ( _ k - l@xmath3 _ ) color - color diagram with the data from table 1 . the progressive reddening in ( _ k - l@xmath3 _ ) is apparent as is the greater variability in ( _ k_-@xmath4 ) at the l to t transition . note that the l7 object , 2massi j1526 + 2043 , has the same ( _ k - l@xmath3 _ ) and ( _ k_-@xmath4 ) colors as an l4 dwarf . this l7 also has 2mass ( _ j_-@xmath11 ) , ( _ j - h _ ) and ( _ h _ -@xmath11 ) colors which are most similar to an l3 or l4 dwarf @xcite . it is possible that this l7 dwarf has been misclassified and this should be kept in mind when studying its location in figures 1 , 2 and 3 . a complete analysis of the l - dwarf @xmath10 scale requires consideration of infrared and optical spectra as well as photometry . however , we can use the results presented here to draw some tentative conclusions by comparing to atmospheric models of @xcite . these models account for sedimentation of atmospheric condensates as described in @xcite . @xcite found that the models with the precipitation efficiency factor @xmath18 best fit the ( _ j - k _ ) colors of the l dwarfs and we use those models here . the models suggest that the ( _ k - l@xmath3 _ ) color of dusty l - dwarf models is insensitive to details of cloud structure or gravity . for 1300 k @xmath19 2100 k a remarkably accurate linear expression ( @xmath20 ) reproduces the ( _ k - l@xmath3 _ ) model colors as a function of @xmath10 . equating this expression with the regression line derived in figure 1 for the ( _ k - l@xmath3 _ ) data gives the following estimate of l dwarf @xmath10 as a function of @xcite spectral type @xmath21 : @xmath22 where @xmath10 is the effective temperature in kelvin , and @xmath21 = 0 to 8 . this equation was fit using only models appropriate for @xmath23 , however the colors depend only slightly on mass for this temperature range , and introduce only a few hundreths variation in the color difference at a fixed @xmath10 . this equation is presented for its heuristic value as an indicator of the @xmath10 range of l - dwarfs and not as a definitive analysis . nevertheless it is interesting to make some comparisons . the earliest l dwarfs appear to have @xmath24 to @xmath25 and the l - dwarf regime extends down to about @xmath26 . on average each @xcite spectral type spans about 100 k in @xmath10 . the @xmath10 derived here for l dwarfs can be compared to the results predicted by other research groups . @xcite compares low resolution spectra and colors of a selection of l dwarfs to models of allard , hauschildt , & schweitzer ( 2000 ) to derive @xmath10 for several objects . their spectral synthesis fitting gave an estimated @xmath10 of 1800 - 1900 k for the entire l dwarf sequence ( l0 to l8 ) . comparison of observed fluxes to evolution models by @xcite resulted in @xmath10 ranging from 2050 - 2350 k for l0 to 1400 to 1600 k for l7 . @xcite proposed that @xmath10 on the @xcite scale varies from about 2200 k ( l0 ) to 1600 k ( l6 ) . the above @xmath10 estimates are all based on fits to the cleared dust " models of @xcite which do not include dust in the radiative transfer . since the @xcite models do include dust opacity , accounting for sedimentation , the atmosphere models are warmer at fixed @xmath10 than comparable cleared - dust models by several hundred degrees . thus the @xmath10 range implied by eq . 1 is cooler and may be more reasonable . our estimated effective temperatures are somewhat higher , particularly for the later - type objects , then those of @xcite who derive temperatures of 2200 k for m9.5 to 1200 k for l7 based on spectral synthesis fitting of far optical spectra using dusty atmosphere models . we note that their fitted @xmath10 depends sensitively upon the treatment of dust and alkali gas opacity as well as the inclusion of an unknown `` additional opacity '' . in contrast the models of @xcite fit both the optical and near - infrared colors of l dwarfs by including a more physically - based description of condensate sedimentation and properly accounting for chemical equilibrium with cloud formation . both dust sedimentation and the chemical equilibrium treatment of alkali metal opacity become more important with later l spectral type @xcite . these effects are likely responsible for the discrepancies between our results . we find that the ( _ k - l@xmath3 _ ) and ( _ k_-@xmath4 ) colors become redder with later l - dwarf spectral type . similarly the ( _ k - l@xmath3 _ ) color of the t dwarfs steadily reddens by a full magnitude over the range of objects observed , and this color may prove useful in the future classification and determination of effective temperature in t dwarfs . we find that ( _ k_-@xmath4 ) for the early t dwarfs is bluer than ( _ k_-@xmath4 ) for the latest l dwarfs due to @xmath1 absorption but that a gradual transition between the two spectral classes is not seen . this suggests that perhaps very early t dwarfs or very late l dwarfs have yet to be found or that @xmath1 absorption appears rapidly over a very small effective temperature range . by using the observed ( _ k - l@xmath3 _ ) colors and theoretical models which include dust opacity and account for cloud sedimentation @xcite , we estimate an @xmath10 range of 2200 k to 1400 k for the entire l - dwarf spectral sequence ( l0 to l8 ) . we thank sandy leggett for helpful comments and advice . d.s . and m.m . acknowledge support from nasa grants nag2 - 6007 and nag5 - 8919 and nsf grants ast-9624878 and ast-0086288 . the data presented herein were obtained at the w.m . keck observatory , which is operated as a scientific partnership among the california institute of technology , the university of california , and the national aeronautics and space administration . the observatory was made possible by the generous financial support of the w.m . keck foundation . we would also like to thank instrument specialists bob goodrich and randy campbell for their support and assistance in using the nirc instrument . ackerman , a. s. , & marley , m. s. 2001 , , submitted allard , f. , hauschildt , p. h. , & schweitzer , a. 2000 , , 539 , 366 basri , g. , mohanty , s. , allard , f. , hauschildt , p. , delfosse , x. , martn , e. l. , forveille , t. , & goldman , b. 2000 , , 538 , 363 bessell , m. s. , & brett , j. m. 1988 , , 100 , 1134 chabrier , c. , baraffe , i. , allard , f. , & hauschildt , p. 2000 , , 542 , 464 delfosse , x. , et al . 1997 , , 327 , l25 delfosse , x. , tinney , c. g. , forveille , t. , epchtein , n. , borsenberger , j. , fouqu , p. , kimeswenger , s. , & tiphne , d. 1999 , , 135 , 41 fan , x. , et al . 2000 , , 119 , 928 fegley , b. , & lodders , k. 1996 , , 472 , l37 gelino , c. , marley , m. , holtzman , j. , ackerman , a. , & lodders , k. 2001 , , submitted gizis , j. e. , monet , d. g. , reid , i. n. , kirkpatrick , j. d. , liebert , j. & williams , r. j. 2000 , , 120 , 1085 hawarden , t. g. , leggett , s. k. , letawsky , m. b. , ballantyne , d. r. , & casali , m. m. 2001 , preprint ( astro - ph/0102287 ) jones , h. r. a. , longmore , a. j. , allard , f. , & hauschildt , p. h. 1996 , , 280 , 77 kirkpatrick , j. d. , et al . 1999 , , 519 , 802 kirkpatrick , j. d. , et al . 2000 , , 120 , 447 leggett , s. k. , allard , f. , & hauschildt , p. h. 1998 , , 509 , 836 leggett , s. k. , et al . 2000 , , 536 , l35 leggett , s. k. , allard , f. , geballe , t. r. , hauschildt , p. h. & schweitzer , a. 2001 , , 548 , 908 marley , m. s. , seager , s. , saumon , d. , lodders , k. , ackerman , a. s. , & freedman , r. 2001 , preprint ( astro - ph/0105438 ) martn , e. l. , delfosse , x. , basri g. , goldman , b. , forveille , t. & zapatero osorio , m. r. 1999 , , 118 , 2466 matthews , k. , & soifer , b. t. 1994 , infrared astronomy with arrays : the next generation , i. mclean , dordrecht : kluwer , 239 mclean , i. s. , et al . 2000 , , 533 , l45 noll , k. s. , geballe , t. r. , leggett s. k. , & marley , m. s. 2000 , , 541 , l75 pavlenko , y. , zapatero osorio , m. r. & rebolo , r. 2000 , 355 , 245 persson , s. e. , murphy , d. c. , krzeminiski , w. , roth , m. , & rieke , m. j. 1998 , , 116 , 2475 reid , i. n. , burgasser , a. j. , cruz , k. l. , kirkpatrick , j. d. , & gizis , j. e. 2001 , , 121 1710 testi , l. , et al . 2001 , , 552 , l147 tokunaga , a. t. , & kobayashi , n. 1999 , , 117 , 1010 tvlm 513@xmath2746546 & m8.5 & 10.74 @xmath28 0.01 & 9.92 @xmath28 0.05 & 10.57 @xmath28 0.05 & 0.82 @xmath28 0.06 & 0.17 @xmath28 0.05 + denis j1159384@xmath29005727 & l0 & 12.80 @xmath28 0.01 & 11.87 @xmath28 0.05 & 12.60 @xmath28 0.04 & 0.93 @xmath28 0.05 & 0.20 @xmath28 0.04 + 2massw j1035245@xmath29250745 & l1 & 13.33 @xmath28 0.02 & 12.56 @xmath280.05 & 14.46 @xmath28 0.06 & 0.78 @xmath28 0.05 & @xmath271.12 @xmath28 0.07 + denis j1441373@xmath27094559 & l1 & 12.66 @xmath28 0.03 & 11.78 @xmath28 0.06 & 13.74 @xmath28 0.06 & 0.88 @xmath28 0.07 & @xmath271.08 @xmath28 0.07 + 2massw j1411175@xmath29393636 & l1.5 & 13.25 @xmath28 0.01 & 12.22 @xmath28 0.04 & 13.08 @xmath28 0.03 & 1.03 @xmath28 0.04 & 0.17 @xmath28 0.03 + 2massw j0928397@xmath27160312 & l2 & 13.63 @xmath28 0.03 & 12.72 @xmath28 0.08 & 13.38 @xmath28 0.06 & 0.91 @xmath28 0.09 & 0.25 @xmath28 0.07 + 2massw j1338261@xmath29414034 & l2.5 & 12.73 @xmath28 0.02 & 11.72 @xmath28 0.05 & 12.49 @xmath28 0.02 & 1.01 @xmath28 0.05 & 0.24 @xmath28 0.03 + 2massw j1615441@xmath29355900 & l3 & 12.92 @xmath28 0.02 & 11.61 @xmath28 0.05 & 12.60 @xmath28 0.05 & 1.31 @xmath28 0.06 & 0.32 @xmath28 0.06 + 2massw j1155009@xmath29230706 & l4 & 14.07 @xmath28 0.01 & 12.75 @xmath28 0.05 & 13.70 @xmath28 0.05 & 1.33 @xmath28 0.05 & 0.38 @xmath28 0.05 + 2massw j1246467@xmath29402715 & l4 & 13.22 @xmath28 0.02 & 11.88 @xmath28 0.04 & 12.79 @xmath28 0.03 & 1.33 @xmath28 0.04 & 0.42 @xmath28 0.03 + 2massw j1112257@xmath29354813 & l4.5 & 12.69 @xmath28 0.02 & 11.38 @xmath28 0.03 & 12.28 @xmath28 0.02 & 1.31 @xmath28 0.04 & 0.41 @xmath28 0.03 + 2massw j1328550@xmath29211449 & l5 & 14.20 @xmath28 0.01 & 13.01 @xmath28 0.06 & 13.84 @xmath28 0.06 & 1.20 @xmath28 0.06 & 0.37 @xmath28 0.06 + 2massw j1553214@xmath29210907 & l5.5 & 14.67 @xmath28 0.02 & 13.26 @xmath28 0.07 & 13.93 @xmath28 0.06 & 1.41 @xmath28 0.07 & 0.74 @xmath28 0.06 + 2massi j0756252@xmath29124456 & l6 & 14.89 @xmath28 0.02 & 13.33 @xmath28 0.07 & 14.56 @xmath28 0.05 & 1.55 @xmath28 0.07 & 0.32 @xmath28 0.06 + 2massw j0829570@xmath29265510 & l6.5 & 14.87 @xmath28 0.02 & 13.23 @xmath28 0.07 & 14.18 @xmath28 0.05 & 1.64 @xmath28 0.07 & 0.68 @xmath28 0.06 + 2massi j1526140@xmath29204341 & l7 & 13.91 @xmath28 0.01 & 12.59 @xmath28 0.06 & 13.50 @xmath28 0.05 & 1.32 @xmath28 0.06 & 0.41 @xmath28 0.05 + 2massi j0825196@xmath29211552 & l7.5 & 13.02 @xmath28 0.01 & 11.34 @xmath28 0.04 & 12.43 @xmath28 0.05 & 1.68 @xmath28 0.04 & 0.59 @xmath28 0.05 + 2massw j1632291@xmath29190441 & l8 & 14.01 @xmath28 0.01 & 12.58 @xmath28 0.08 & 13.52 @xmath28 0.05 & 1.43 @xmath28 0.08 & 0.49 @xmath28 0.05 + sdss 0837172@xmath27000018 & t1 & 15.97 @xmath28 0.04 & 14.42 @xmath28 0.11 & 15.71 @xmath28 0.09 & 1.54 @xmath28 0.12 & 0.26 @xmath28 0.10 + sdss 1254539@xmath27012247 & t2 & 13.95 @xmath28 0.01 & 12.12 @xmath28 0.05 & 13.62 @xmath28 0.04 & 1.83 @xmath28 0.05 & 0.34 @xmath28 0.05 + sdss 1021097@xmath27030420 & t3 & 15.40 @xmath28 0.03 & 13.53 @xmath28 0.10 & 15.53 @xmath28 0.08 & 1.86 @xmath28 0.10 & @xmath270.13 @xmath28 0.08 + sdss 1346465@xmath27003150 & t6 & 15.89 @xmath28 0.03 & 13.55 @xmath28 0.06 & 15.56 @xmath28 0.07 & 2.35 @xmath28 0.07 & 0.34 @xmath28 0.08 + sdss 1624144@xmath29002916 & t6 & 15.66 @xmath28 0.02 & 13.22 @xmath28 0.06 & 15.43 @xmath28 0.09 & 2.44 @xmath28 0.07 & 0.24 @xmath28 0.10 +

we present _ k_- and _ l_-band photometry obtained with the keck i telescope for a representative sample of l and t dwarfs . these observations were motivated in part by the dominant role @xmath0 and @xmath1 play in shaping the flux near 2 and 3 @xmath2 m and by the potential use of these bands as indicators of spectral class in the infrared . in addition , these observations aid the determination of the bolometric luminosity of l and t dwarfs . here we report the _ k _ , _ l@xmath3 _ and @xmath4 magnitudes of our objects and the trends observed in the ( _ k - l@xmath3 _ ) and ( _ k_-@xmath5 ) colors as a function of l- and t - dwarf spectral class . we compare these colors with theoretical models , derive a relationship between effective temperature and l - spectral class , and compare our temperature estimates with others .

the terms congenitally missing , absence , developmental hypodontia , and tooth agenesis are all expressions used to describe the failure of 1 to 5 permanent teeth to form ; this is a relatively common occurrence with an incidence of 3 - 8% in the general population.1,2 with the exception of third molars , the most frequently observed missing teeth are mandibular second premolars and maxillary lateral incisors . to answer this question , orthodontists must know the developmental stages of the permanent dentition . odontogenesis of second premolars has been reported to show greater variability than other permanent teeth.2,3 while moorrees et al.4 showed that the calcification of second premolars are initiated between 2 and 2.5 years of age , nolla5 reported that the crypt of mandibular second premolars is usually apparent at 3 years of age . the results of another longitudinal study indicated that second premolar formation is initiated at 3 - 3.5 years of age in most cases.6 because of the large variability in odontogenesis , an orthodontist should ideally wait until a patient is 5 - 6 years old before giving the final agenesis diagnosis decision for mandibular second premolars . treatment of congenital tooth absence consists of 2 main treatment options : the first option involves replacing the residual space with implants or fixed prostheses and closing the spaces by moving the adjacent teeth into the residual space ; the second option is to retain the deciduous tooth if its roots seem adequate , but modify its morphology if necessary . however , if the second op tion is chosen , orthodontists must keep in mind that prosthesis will have to be constructed anyway if the root of a deciduous tooth resorbs later in life . if not contraindicated , closing the space between missing teeth with the patient 's own teeth is the most preferable option for both orthodontist and the patient . when this option is chosen , the orthodontist may perform this treatment without hesitation , including the extraction of the mandibular second deciduous molars to permit mesial drift of the first permanent molars spontaneously or orthodontically if the patient is over 6 years old . however , the risk involved in this treatment approach is presented in this case report that demonstrates how we approached orthodontic treatment in an 8.5-year follow - up study of an 8-year - old girl exhibiting late odontogenesis of a mandibular right second premolar . a female patient aged 8 years and 1 month was referred to the department of orthodontics in the faculty of dentistry at cumhuriyet university with a major complaint of maxillary anterior crowding . a detailed intraoral examination revealed that the patient was in early deciduous dentition and had a well - aligned mandibular arch and class ii molar relationship on both sides ; additionally , her maxillary left lateral incisor was in cross - bite . a panoramic radiograph showed that the permanent mandibular second premolars were absent ( figure 1 ) , and lateral cephalometric evaluations revealed that the patient had a slightly high vertical growth pattern ( table 1 ) . the main treatment plan included the following objectives : obtaining a functional occlusion , correcting the cross - bite of the maxillary lateral incisor , and closing the mandibular deciduous second molar space by mesial movement of the permanent first molars . the first alternative was to retain the deciduous second molars , as the roots were adequate , and to distalize the maxillary first molars to achieve a class i molar relationship in addition to correcting the cross - bite of the maxillary left lateral incisor . however , the patient had a vertical growth pattern ; if the roots of deciduous second molars would resorb later in life , then the residual space would need to be rehabilitated with an implant prosthesis . the second alternative involved the extraction of the deciduous second molars followed by mesialization of the permanent first molars into the extraction space , despite the prolonged treatment time to move the first permanent molar about 8 mm . in this second treatment plan , the case was evaluated in detail and the options were proposed to her parents ; finally , the second alternative was chosen considering the vertical growth pattern of the patient and the cost of the implant prosthesis . the cross - bite of the maxillary left lateral incisor was corrected by using a removable appliance , including a labiolingual spring , for 2 months . interestingly , a developing mandibular right second premolar was clearly observed on a panoramic radiograph approximately 17 months later when the patient was 9 years and 6 months old ( figure 2 ) . the germ of the maxillary left third molar was also seen at the same time . following this development , we revised the treatment plan and decided to wait for possible odontogenesis of the permanent left premolar as well as evaluate the calcification process of the right premolar . while there was no evidence of mandibular left second premolar odontogenesis at 2 years after the first appointment ( when the patient was 10 years and 2 months old ) , calcification of the maxillary right third molar and crypt formation of the mandibular right third molar were observed ( figure 3 ) . however , at this time the deciduous left second molar roots had resorbed , even though its successor was absent . three years and 2 months after the first appointment , the mandibular left third molar 's crypt formation was observed in addition to advancement of the other third molars and calcification of the mandibular right second premolar . because the formation of all third molars occurred and there was no evidence of mandibular left second premolar odontogenesis , we considered this premolar to be congenitally absent . following the revised treatment plan , the deciduous left second molar was extracted and the permanent left first molar was allowed to drift mesially ( figure 4 ) . in addition , the maxillary left permanent second premolar was also extracted to establish a class i molar relationship . a removable appliance was constructed for both the lower and upper arch , and necessary adjustments were made to achieve parallel movement . after all permanent teeth reached occlusion , except the third molars and mandibular right second premolar , 0.018-inch slot roth prescription brackets ( american orthodontics ) were placed on both arches ; leveling started with 0.012-inch nickel - titanium archwires . the spaces were closed , midlines were corrected , class i molar and canine relationships were achieved , and growth pattern remained almost stable after 19 months of fixed appliance therapy ( table 1 ) . the mandibular right second premolar became exposed within the oral cavity 7 years and 4 months after the initial appointment ( figure 5 ) and reached occlusion 15 months after first exposure ( figure 6 ) . previous studies have revealed that mandibular second premolars exhibit the greatest variations in differentiation and calcification among all teeth , except for the third molars.2,3 calcification of these teeth usually begins approximately 2 - 2.5 years of age , with 2 standard deviations at less than 3.5 - 4 years of age ; crown formation is usually completed by 6 - 8 years.4 however , the calcification of mandibular second premolars at approximately 5 - 6 years of age is not a rare condition.6,7 second premolar agenesis can usually be confirmed when the patient is 8 - 9 years of age , because reasonably few second premolars form after this age.6 in the case presented here , initial radiographs showed that the mandibular second premolars were absent when the girl was 8 years and 1 month old . however , we observed that this patient unexpectedly developed late formation of the right second premolar at almost 10 years of age . according to our assessment at that time , we could not presume the possibility of this late formation of second premolars in an 8-year - old girl . moreover , we were not surprised to find that the patient did not develop second premolars beneath the mandibular second deciduous molars at this age because that is the con genital tooth absence most commonly seen in this region . consequently , we created a treatment plan that included the extraction of deciduous second molars and mesialization of permanent first molars . fortunately , this treatment procedure was never followed through ; because of the late formation of the right second premolar observed at a subsequent follow - up , and the treatment plan was revised . in cases where there is an absence of a successor tooth , lindqvist8 recommends extraction of the retained mandibular deciduous second molar within the period between 8 years of age and completion of root development for the first permanent molar in order to obtain maximum space closure by bodily drift of the adjacent teeth . however , in a few cases , such as the one reported here , this approach might induce irreversible consequences is the overlying deciduous teeth is not retained until the roots of the successor teeth have formed . delay in tooth formation is considered a milder representation of tooth agenesis.9 - 11 one study revealed that , compared to the control group , a group of children affected by hypodontia experienced a significant delay in dental development.12 moreover , rune and sarns13 presented data suggesting a tendency toward excessive retardation of tooth formation in teeth contralateral to missing teeth . however , a tooth contralateral to the late - developed second premolar was not formed in the case presented in our study . studies investigating the genetic and molecular genetic causes of agenesis have begun to identify genes important in tooth agenesis.9 the transcription factor genes msx1 and pax9 were the first genes identified for nonsyndromic tooth agenesis.14,15 although both genes affect third molars , a significantly higher frequency of agenesis associated with mutations in msx1 than in pax9 has been found for second premolars and maxillary first premolars.9 third molar agenesis was suggested to be a complex anomaly that may be related to delayed calcification of posterior teeth.16 however , in the case presented here , all third molars were developed ; consequently , this situation demonstrated that there was no association between the developmental absence of third molars and the delayed formation or agenesis of the second premolar . this finding was similar to the results presented by previous case reports.17 - 19 these findings therefore suggest that the cause of the delayed formation of the mandibular right second premolar with a congenital absence of a contralateral premolar might be the result of msx1 mutation . overall , this case demonstrated that orthodontists should always be aware that unusual circumstances can occur , especially when treating growing patients . to reduce the risk of misdiagnosis furthermore , periapical radiographs should be taken at regular intervals every 6 months in growing patients exhibiting tooth agenesis . consequently , follow - up radiography should be performed prior to giving a final hypodontia diagnosis decision , especially after deciduous second molar extraction but before space closure .

in this report , we present the case of a girl with delayed odontogenesis of a lower second premolar for which she was followed up for 8.5 years . congenital absence of permanent mandibular second premolars was observed at the initial radiographic examination at 8 years and 1 month . one year later , during the treatment period , an unexpected odontogenesis of a right second premolar was diagnosed on follow - up radiography . the original treatment plan was revised and a new plan was successfully implemented . th is unusual case showed that the orthodontist 's clinical philosophy must be flexible because unexpected situations can arise , especially when treating growing patients .

splenic torsion of the so called wandering spleen is an extremely rare phenomenon , having an incidence of 1 in 2000 and accounts for only 2 per 1000 splenectomies . an 18 year old married female patient presented to the obstetrics and gynaecology emergency unit with severe pain and abdominal distension for one day . there was no history of vomiting , constipation or fever . her period was overdue by about 40 days when she presented in the emergency department . she was found to be very pale and was haemodynamically unstable with an uncordable blood pressure . her abdomen was distended and tender , without any significant rebound tenderness . per rectal examination was normal . per vaginal examination showed a bulky uterus , a distended pouch of douglas and adnexae were found to be apparently normal . as emergency ultrasonographic or other imaging facility was not available at that time a culdocentesis was done which revealed haemoperitoneum . as patient was deteriorating rapidly , an urgent laparotomy was done with a provisional diagnosis of a ruptured ectopic pregnancy . she was found to have about 2 litres of dark coloured blood with clots in her abdomen . examination of the pelvis revealed normal fallopian tubes and ovaries but the uterus was bulky . a hugely enlarged and congested spleen , transversely oriented was found with multiple ruptures on its surface . the hilum and splenic pedicle could not be identified initially as the spleen had rotated three and a half times on its pedicle . two units of blood were transfused peri - operatively and two units post - operatively . no tumour mass or any other significant pathology was found . on day 3 post - op , she further underwent a check curettage for evacuation of retained products of conception . following this , the patient made a full recovery splenic torsion with spontaneous rupture in a patient with early intrauterine pregnancy is an extremely rare cause of acute abdomen . the diagnosis is extremely difficult as seen in the case where it masqueraded as a ruptured ectopic pregnancy . the exact aetiology is unknown but it is probably due to incomplete fixation of gastrosplenic and lienorenal ligaments which gives rise to the so called wandering spleen . ( 3 ) presentation is highly variable and there are reports of this entity presenting as an acute abdomen , abdominal mass or even as intestinal obstruction . the acquired form is usually seen in multiparous women possibly as a result of hormonal changes in pregnancy that cause laxity of the abdominal wall and the ligaments attached to the spleen . ( 7,8 ) splenomegaly has been known to elongate the splenic pedicle by traction , increasing preponderance to torsion and splenoptosis . ( 9 ) torsion may then cause venous congestion , further splenomegaly , elongation of vascular pedicle and splenoptosis . as the condition is very rare often there is not enough time for radiological investigations but if possible a ct scan or ultrasound should be done . this report brings out the importance of considering splenic torsion in the differential diagnosis of all cases of acute abdomen , particularly when we do not have the time or facility to carry out a full radiological evaluation .

splenic torsion with rupture of spleen is an extremely rare phenomenon . the clinical picture mimics several common conditions which are causes of acute abdomen and so it is seldom detected pre - operatively . an 18 year old female patient was admitted with an acute abdomen and shock . the provisional diagnosis was of a ruptured ectopic pregnancy . peri - operatively we found a spontaneous rupture of the spleen following torsion along with early intrauterine pregnancy . splenectomy was carried out and patient recovered well . our report confirms that this rare entity can present as an acute abdomen which is very difficult to diagnose preoperatively and can masquerade as ruptured ectopic pregnancy in women of childbearing age group .

is one of the most unusual members of the class of dipping low mass x - ray binary ( lmxb ) sources exhibiting periodic dips in x - ray intensity . it is generally accepted that dipping is due to absorption in the bulge in the outer accretion disk where the accretion flow from the companion inpacts ( white & swank 1982 ) . has the longest orbital period of the dipping sources at 21@xmath92 hr ( watson et al . 1985 ) , but the period has not been refined since this determination from _ exosat_. dipping is deep , @xmath10 75% in the band 110 kev , and the source also exhibits strong flaring in which the x - ray flux can increase by 30% over timescales of a few thousand seconds ( church & bauciska - church 1995 ) . the depth , duration and spectral evolution in dipping vary considerably from source to source . however , spectral analysis of dipping sources provides information not available in non - dip sources . for example , spectral models are more strongly constrained by having to fit non - dip and dip data , thus showing clearly the nature of the emission . in addition , the dip ingress and egress times can be used to obtain the sizes of the extended emission regions when the absorber has larger angular extent than the source regions , thus providing information on the geometry of the accretion disk corona ( adc ) ( e.g. church et al . although the fundamental question of the nature of the emission regions in lmxb is controversial , a unifying model has been proposed for the dipping class ( church & bauciska - church 1995 ) which is able to explain the widely disparate behaviour of individual sources . the emission regions consist of the point source neutron star producing blackbody emission , and an extended comptonizing region , probably the adc . it has now been shown that this model not only can explain well the spectra of _ all _ dipping lmxb ( church et al . in preparation ) , but can also explain the spectra of all the z - track and atoll sources investigated in a recent _ asca _ survey ( church & bauciska - church 2000 ) . in a number of dipping sources , the nature of dipping was not understood because of the clear presence of an unabsorbed part of the non - dip spectrum at all levels of dipping . in these sources , dip spectra could be modelled by dividing the non - dip spectral form into two parts : one absorbed and the other unabsorbed but with strongly decreasing normalization ( parmar et al . 1986 ; courvoisier et al . 1986 ; smale et al . 1992 ) , ` absorbed plus unabsorbed ' modelling . it has been difficult however , to explain these normalization changes convincingly . more recently , an alternative explanation has been suggested in which an extended absorber moves across the extended and point - like emission regions , providing a natural explanation for the unabsorbed component as the uncovered emission which becomes smaller as dipping proceeds . this progressive covering model has explained spectral evolution during dipping in xb1916 - 053 , xb0748 - 676 and xb1323 - 619 ( church et al . 1997 , 1998a , b ; bauciska - church et al . 1999 ) . was previously observed in a long _ exosat _ observation of 220 ks and with _ ginga _ ( jones & watson 1989 ) . the _ exosat _ me data revealed an apparently stable lower level of dipping supporting the presence of two emission components , one of which was totally absorbed in deep dipping . a blackbody plus bremsstrahlung model was used to parameterize the spectra ( jones & watson 1989 ) . church & bauciska - church ( 1995 ; hereafter cbc95 ) showed that the light curve at higher energies ( @xmath11 5 kev ) was dominated by flaring which can strongly modify the spectrum and make the spectral investigation of dipping difficult . by selecting sections of non - dip and dip data without apparent flaring , the above unifying blackbody plus comptonization model was found to fit the data well showing that in deep dipping the blackbody component was totally absorbed , and that the comptonized component was relatively little absorbed . however , with only one non - dip and one deep dip spectrum it was not possible to determine the extent of absorption of the comptonized component . the galactic column density of is very high @xmath12 atom @xmath13 so that a dust scattered halo of the source is expected , and angelini et al . ( 1997 ) demonstrated an excess of the surface brightness above the point spread function in _ asca _ gis . in the present paper , we present a detailed study of dipping in x1624 - 490 and of the effects of dust scattering in this source made using _ bepposax_. with the very broad band , we have been able for the first time to obtain reliably parameters of the comptonized emission . we also present a determination of the orbital period of from the _ rxte _ asm . data from the low - energy concentrator spectrometer ( lecs ; 0.110 kev ; parmar et al . 1997 ) , medium - energy concentrator spectrometer ( mecs ; 1.310 kev ; boella et al . 1997 ) , high pressure gas scintillation proportional counter ( hpgspc ; 5120 kev ; manzo et al . 1997 ) and the phoswich detection system ( pds ; 15300 kev ; frontera et al . 1997 ) on - board are presented . all these instruments are coaligned and collectively referred to as the narrow field instruments , or nfi . the mecs consists of three identical grazing incidence telescopes with imaging gas scintillation proportional counters in their focal planes , however prior to the observation of one of the detectors had failed . the lecs uses an identical concentrator system as the mecs , but utilizes an ultra - thin entrance window and a driftless configuration to extend the low - energy response to 0.1 kev . the non - imaging hpgspc consists of a single unit with a collimator that is alternatively rocked on- and off - source to monitor the background spectrum . the non - imaging pds consists of four independent units arranged in pairs each having a separate collimator . each collimator can be alternatively rocked on- and off - source to monitor the background . the region of sky containing was observed by between 1999 august 11 00:47 and august 11 18:22 utc . good data were selected from intervals when the elevation angle above the earth s limb was @xmath11@xmath14 for lecs and mecs , @xmath11@xmath15 for the hpgspc and @xmath11@xmath16 for the pds and when the instrument configurations were nominal , using the saxdas 1.3.0 data analysis package . the standard collimator dwell time of 96 s for each on- and off - source position was used , together with rocking angles of 180and 210 for the hpgspc and pds , respectively . the exposures in the lecs , mecs , hpgspc , and pds instruments are 16 ks , 34 ks , 17 ks , and 16 ks , respectively . lecs and mecs data were extracted centered on the position of using radii of 8 and 4 . background subtraction in the imaging instruments was performed using standard files scaled appropriately to match the background level in the image , this being required because of the location of the source in the galactic plane , but is not critical for such a bright source . background subtraction in the non - imaging instruments was carried out using data from the offset intervals . figure 1 shows the background - subtracted mecs lightcurves of with a binning of 32 s in two energy bands : 1.85.0 kev and 5.010.0 kev . observation of dipping is difficult in this source with a long orbital period if the total observation time is to be kept within limits . in this case the observation was carried out on the basis of a dipping ephemeris we obtained from the _ rxte _ asm , aiming for the dipping to occur at the centre of the observation . dipping was detected as seen in fig . 1 , lasting between 3.6 and 8.4 ks with parts being missed in data gaps . the total count rate was @xmath011 count s@xmath6 . data in the high energy band reveal little flaring which was clearly seen in the _ exosat _ me as increases in count rate above 5 kev lasting several thousand seconds ( cbc95 ) , except for an increase in count rate of 20% at @xmath032 ks lasting 1.4 ks . we detected little effect in the spectral fitting that might be due to flaring . an expanded view of the dipping in the band 1.810 kev is shown in fig . 2 revealing strong variability on timescales of @xmath032 s proving `` blobbiness '' in the absorber . dips are not strongly evident in the hpgspc and pds lightcurves due to the comparatively reduced signal - to - noise ratio in these instruments and the energy dependence of the dipping . it can be seen from fig . 1 having 32 s binning that dipping is not 100% deep in either energy band unlike , for example , xb1916 - 053 in which dipping often reaches 100% depth at all energies below 10 kev ( church et al . however , because of the fast dip ingress and egress times , 32 s binning is not short enough to reveal the true depth . tests showed that 8 s binning was adequately short , in which case the depth of deepest dipping was @xmath17% and @xmath18% = 80 mm in the bands 1.85.0 kev and 5.010.0 kev respectively . in fig . 3 we show the results of determining the depth of dipping in the energy bands 2.53.5 kev , 3.54.5 kev , 4.55.5 kev , 5.56.5 kev and 6.57.5 kev from mecs data with 8 s binning . results are shown for data extracted in the standard radius of 4 and also for extraction radii of 2 and 15@xmath19 . for 15 extraction , it was necessary to subtract background to avoid errors in the depth . it was not possible to obtain results outside the overall band of 2.57.5 kev because of poor statistics . although there is no dramatic change in depth with energy , = 80 mm there is evidence for the depth increasing at low energies , particularly for 2 extraction with 90% deep dipping at 2.53.5 kev . there is also evidence that dipping was deeper with 2extraction , but no evidence for differences between 4 and 15 extraction . thus dipping is @xmath0 80% deep over much of the 110 kev band , but is not actually proven to be 100% at any energy . there can be two reasons for this . because the galactic column density in appears to be high , dust scattering is expected to be important and below 5 kev this can result in a non - zero intensity level in deepest dipping . above @xmath05 kev , dust scattering will not be important , and non - zero dip intensity can be due to incomplete absorption of one emission component . the increase in depth of dipping in 2extraction is consistent with a decreased amount of dust - scattered halo . the column density of x1624 - 490 from spectral fitting is high and so we have investigated possible effects of dust scattering . this is discussed in detail in sect = 80 mm we can not carry out folding analysis of the present x - ray light curve to determine the orbital period ; however , we have examined the _ rxte _ asm data on this source to determine the period more accurately which previously was only poorly known at 21@xmath92 hr ( watson et al . data were used between 1996 , feb . 20 and 2000 , jan . 18 and a period search carried out using standard ( xronos ) power spectrum software spanning the period range 2.5 @xmath20 hr . peaks were seen with high significance corresponding to periods of 20.87@xmath21 hr and 10.438@xmath22 hr , the significance of each of these peaks corresponding to a probability @xmath23 99.8% of being real . 32 days of data folded on the period of 20.87 hr are shown in fig . 4 , in which dipping is clearly seen to repeat at 20.87 hr with interdipping also seen between the main dips . this is the first detection of interdipping in this source . in the four years of asm data analysed , the depth of dipping investigated in 32 day sections of data varies , and in particular , the depth of interdipping varies from being as deep as the main dipping to being undetectable . there is some evidence that this pattern repeats on a timescale of @xmath070 days , but this can not yet be identified definitely as a new periodicity in the system . the 10.438 hr periodicity can not be the orbital period for several reasons : firstly this periodicity is at times not present in the asm data when the 20.87 hr periodicity is present . additionally , fig . 4 shows dipping at 10 hr from the main dips is weak , entirely consistent with interdipping . if the orbital period were 10.438 hr , then a strong peak at 21 hr would not be seen in the power spectrum . finally , the _ exosat _ me lightcurve ( jones & watson 1989 ; church & bauciska - church 1995 ) allows the possibility of a 10-hr orbital period to be almost certainly rejected . although the column density of x1624 - 490 is high ( @xmath24 atom @xmath13 in the present work ) , implying that dust scattering effects will be important , radio measurements have indicated a lower value of @xmath25 atom @xmath13 ( dickey & lockman 1990 ; stark et al . 1992 ) ( although these measurements may underestimate @xmath26 when this is high ) , so that there is a possibility that the high value of @xmath26 is due to absorption intrinsic to the source . to investigate dust scattering , we have carried out modelling of the radial intensity distribution . this was done using mecs data since spectral evolution during dipping was investigated primarily with mecs . the modelling was based on the technique used by predehl & schmitt ( 1995 ; hereafter ps95 ) in their investigation of 25 galactic sources ( not including x1624 - 490 ) subject to high galactic column densities using the _ rosat _ pspc . in the case of we find excesses in the radial profile above the point spread function ( psf ) of the instrument for radii greater than @xmath0100@xmath27 indicating a substantial halo contribution . software has been developed to allow fitting the radial distribution including the source contribution convolved with the psf , a dust - scattered halo calculated on the basis of rayleigh - gans scattering theory with its associated radial distribution function ( predehl & klose 1996 ; ps95 ) , plus a background contribution . as the source lies in the galactic plane , the standard background files are not applicable , and we adopted the same approach as ps95 and allowed the background to be a free parameter . a more complete treatment would also convolve the halo with the energy - dependent psf . however , we investigated the effect of this and found that the value of the optical depth to dust scattering would only be reduced by up to 20% . the point spread function of boella et al . ( 1997 ) was utilised and ximage used to provide a radial distribution function of the data . from the best fit of the model to the data , the halo intensity fraction _ f@xmath28 _ was derived , where _ f@xmath28 _ is defined as the fraction of the observed intensity due to the halo , and may be written in terms of the observed source intensity @xmath29 and the observed halo intensity @xmath30 as @xmath31 these procedures were tested by applying them to the bright z - track source gx17 + 2 which has been observed both with _ rosat _ and _ bepposax_. firstly , we modelled the pspc data on gx17 + 2 and derived results similar to those of ps95 . next , we modelled the mecs data on this source . in the case of gx17 + 2 only , ps95 obtained halo fractions in 7 energy bands within the overall pspc band , which has allowed us to compare mecs results with their results at an energy where the mecs and the pspc bands overlap . in the band 1.72.1 kev a good fit was obtained with a @xmath32/dof of 78/74 , and a halo intensity fraction at 1.9 kev of @xmath33% , compared with the value of 26% which = 80 mm we obtain from fig . 8 of ps95 at this energy . this good agreement gives us confidence that the modelling was correct , and that reliable values of _ f@xmath28 _ can be obtained using _ bepposax_. next , modelling was carried out for x1624 - 490 . initially the mecs data were binned to a minimum of 20 counts per radial bin , then further grouping was applied with radial bins grouped together in pairs to reduce fluctuations . systematic errors of 10% were added between 10100 where the psf is uncertain by about this amount , and 2% between 100 - 1000 to account for uncertainties in the psf , faint , barely resolved sources in the field of view , and other effects . radial bins between 500 - 700 were ignored where a detector support structure causes an artificial reduction in the radial profile . the fitting was done in four energy bands : 2.53.5 , 3.54.5 , 4.55.5 and 5.56.5 kev . the best - fit solution is shown in fig . 5 for the lowest band 2.53.5 kev in which the halo was strongest . values of the halo fraction _ f@xmath28 _ from the best - fit models were found to be : @xmath34% , @xmath35% , @xmath36% in the three lowest energy bands . in the band 5.56.5 kev , there was no evidence for any departure of the radial profile from the psf , and no improvement in the quality of fit by including a halo term in the model . we also calculated the halo fractions of the total count from these fitting results by integrating to a restricted outer radius of 4@xmath19 , the extraction radius used for mecs spectra ( sect . the fractions became : @xmath37% , @xmath38% , @xmath36% and @xmath39 2% respectively , in the four bands . when these fractions are compared with the depth of dipping in these bands ( fig . 3 ) , it can be seen that the halo can not explain the fact that dipping does not reach a depth of 100% , particularly at the higher energies . as discussed in sect . 3.5 , this must be due to incomplete absorption of an extended emission component . in fig . 2 we compare the halo contribution to the intensity ( dashed line ) calculated from our results for the band 1.810 kev with the depth of dipping . using this limited number of energy bands , we have compared the energy variation with theoretical expectations , and derived the optical depth to dust scattering @xmath40 , evaluated at 1 kev . the reduction in source intensity is given by @xmath41 , from which it can be shown that the halo fraction and @xmath40 are related _ via _ @xmath42 , provided that the intensity scattered out of the line - of - sight is balanced by that scattered into the line - of - sight as is normally assumed ( e.g. martin 1970 ) . since the dust scattering cross - section is expected theoretically to vary as @xmath43 ( mauche & gorenstein * * 1986 ) , then the optical depth will also have this dependence , and @xmath44 where @xmath45 is the optical depth at 1 kev , normally quoted . using this relation , we have derived a value at 1 kev of @xmath40 = 2.4@xmath46 . within the errors on the individual values of _ _ , the data are consistent with an @xmath43 dependence of the cross - section . the results show that dust scattering in the case of is large . furthermore , we can compare the above value of @xmath40 with values in fig . 7 of ps95 , in which @xmath40 is plotted against the x - ray column density for the 25 galactic sources in this survey , and varies between zero and @xmath01.5 . thus in x1624 - 490 , @xmath40 is much larger . the value of @xmath40 we obtain , and the value of @xmath26 from spectral fitting of @xmath47 atom @xmath13 may be compared with the linear @xmath40@xmath48 relation obtained by ps95 . this best relation : @xmath40 = @xmath49-\,0.083}$ ] predicts in our case ( @xmath40 = 2.4 ) that @xmath26 = @xmath50 atom @xmath13 , compared with our fitting result of @xmath47 atom @xmath13 for the non - dip spectrum . the difference between these may imply a flattening of the relation at higher column density , or possibly intrinsic absorption in the source . it has been shown that a substantial dust scattering halo is observed in x - rays around x1624 - 490 , and we now consider prior to presenting spectral fitting results how spectra will be affected . in the case of non - dip spectra , the effect is , in fact , expected to be zero ( provided all of the halo is collected ) , since radiation removed from the line - of - sight is replaced by that scattered into the line - of - sight by scattering , both effects taking place predominantly at lower energies , so that the net effect on the non - dip spectrum is zero . the consequence of this is that the observed intensities due to halo : @xmath30 and due to the source @xmath29 are equal to the source intensity that would have been observed without scattering ; i.e. @xmath51 consequently , we did not include a dust scattering term in fitting the non - dip spectra . however , in dipping , the intensity lost by dust scattering is proportional to the dip source intensity while the intensity gained depends on the non - dip intensity because of the time delays in scattered radiation compared with unscattered . thus , in dip data there will be an additional dust scattered component . we have carried out spectral fitting of the mecs dip spectra firstly without any additional component , and then secondly adding terms to account for the effects of dust scattering both out of and into the line - of - sight . the total halo contains both blackbody and cut - off power law terms from the spectrum incident to scattering . the spectrum of non - dip emission was investigated by simultaneously fitting data from all the nfi . non - dip mecs data were selected by choosing a narrow intensity band from 9.710.3 count s@xmath6 , also removing the dip data by time filtering . lecs , hpgspc and pds data corresponding to these mecs data were selected . spectral evolution in dipping was investigated using mecs data only since the dips are not strongly seen at higher energies and there are too few counts in the lecs to contribute meaningfully . for non - dip data , the lecs and mecs spectra were rebinned to oversample the full width at half maximum of the energy resolution by a factor of 3 , and additionally lecs data were rebinned to a minimum of 20 counts per bin and mecs data to 40 counts per bin to allow use of the @xmath52 statistic . the lecs and mecs non - dip spectra were also more heavily grouped to a minimum of 100 counts per bin in each case , as experience has shown that more stable fitting may result . however , in this case , results obtained with the alternative groupings were in excellent agreement . lecs data were only used between 14 kev and mecs data between 1.710.0 kev where the instrument responses are well determined . the hpgspc data were rebinned using standard binnings in the bands 734 kev and pds data were grouped appropriately for this source in which the data decrease rapidly with energy . pds data outside the band 150220 kev were ignored . llllll model & n@xmath53 & kt ( kev ) & @xmath54 & @xmath55 ( kev ) & @xmath52/dof + power law & @xmath56 & & @xmath57 & & 867/297 + bremsstrahlung & @xmath58 & @xmath59 & & & 402/296 + blackbody & @xmath60 & @xmath61 & & & 651/297 + disk blackbody & @xmath62 & @xmath63 & & & 390/297 + cutoff power - law & @xmath64 & & @xmath65 & @xmath66 & 396/296 + disk blackbody + cut - off power law & @xmath67 & @xmath68 & @xmath69 & @xmath70 & 291/294 + blackbody + cut - off power law & @xmath71 & @xmath72&@xmath73 & @xmath74 & 287/294 + [ tab : spec_paras ] = 110 mm in the following , the photoelectric absorption cross sections of morrison & mccammon ( 1983 ) were used incorporating the solar abundances of anders & grevesse ( 1989 ) . initially , the non - dip spectrum was fitted with simple models , including absorbed power - law , thermal bremsstrahlung , blackbody and cut - off power law models . factors were included in the spectral fitting to allow for normalization uncertainties between the instruments . results are shown in table 1 . the power - law model was completely incapable of fitting the broad - band spectrum producing a @xmath52/dof of 867/297 ; this was only achieved at the expense of a pds normalization factor of 0.28 relative to mecs which can not be real lrlllr spectrum & mecs ct & @xmath75 & @xmath76 & f & @xmath52/dof + & rate ( s@xmath6 ) + ( a ) without halo components + non - dip & 9.710.3 & [email protected] & [email protected] & 0.0&150/151 + shallow dip & 6.08.0 & 27@xmath97 & 25@xmath914 & @xmath00.085 & 37/28 + medium dip & 4.06.0 & 52@xmath917 & 50@xmath930 & @xmath77&24/27 + deep dip & 2.04.0 & 94@xmath920 & 63@xmath78 & @xmath79&2/7 + ( b ) with halo components + non - dip & 9.710.3 & [email protected] & [email protected] & 0.0 & 151/152 + shallow dip & 6.08.0 & 25@xmath910 & 21@xmath80 & [email protected] & 38/28 + medium dip & 4.06.0 & 45@xmath8118 & 40@xmath82 & @xmath83 & 23/27 + deep dip & 2.04.0 & 100@xmath84 & 40@xmath85 & @xmath86&2/7 + [ tab : dips ] and strong discrepancies between model and data in the pds band due to down - curving in the spectrum . the bremsstrahlung model similarly did not provide an acceptable fit with a @xmath52/dof of 402/296 . an absorbed blackbody model gave a fit with @xmath52/dof of 651/297 , the spectrum being much broader than any simple blackbody . an absorbed multi - temperature disk blackbody similarly could not fit , the model falling below the data above 10 kev . an absorbed cut - off power law model also gave a poor fit with a @xmath52/dof of 396/296 and a low value of the comptonization cut - off energy of @xmath87 kev which is not consistent with the spectrum extending to high energies as observed . a two - component model consisting of a disk blackbody plus a cut - off power law gave @xmath52/dof almost as good as the best model ( below ) but with unphysical power law index and an inner radius for the disk blackbody of @xmath00.4 km which is also unphysical . we next tried the two - component model used extensively to fit other members of the dipping class ( see sect . 1 ) , in which the emission regions are point - like blackbody from the neutron star and extended comptonized emission from the adc . this model gave an acceptable fit with a @xmath52/dof of 287/294 . the unfolded spectrum of this best - fit model is shown in fig . the values of the normalization factors for the individual instruments ( relative to the mecs ) were similar to those found for other sources . after initial trials , mecs dip spectra were extracted with count rates between 2.04.0 count s@xmath6 , 4.06.0 count s@xmath6 and 6.08.0 count s@xmath6 after first binning the data in 8 s intervals . additionally , a spectrum was initially selected with 8.09.0 count s@xmath6 , but this lay too close to the non - dip spectrum for parameters to be well - determined as is often found . given the count rate of the source , a larger number of dip spectra would not be sensible . tests showed that in this source , in which there is fast variability during dipping , binning the data into bins longer than 8 s before spectra were extracted resulted in unacceptable averaging with the consequence that the depth of dipping can appear less than it actually is . an acceptable spectral model must be able to fit both non - dip and all dip spectra , without any changes in the parameters that characterize the source emission such as blackbody temperature or power law index . in the case of weak sources , it may be necessary to fit non - dip and dip spectra simultaneously , however in good fits were obtained by applying the non - dip solution to the dip spectra and using the progressive covering model . this model was firstly applied without any additional halo component . in this model , the emission components of the best non - dip fit are progressively covered by absorber , i.e. the extended comptonized emission is progressively covered and the point - like blackbody is rapidly removed when the envelope of the absorber overlaps the blackbody . the model flux may be written : @xmath88 good fits were obtained for all levels of dipping with this model as shown in table 2a . it can be seen however , that the covering fraction does not rise above 50% which is inconsistent with other sources in which the progressive covering fraction rises to 100% , e.g. xb1916 - 053 and xbt0748 - 676 ( church et al . 1997 , 1998a , b ) . = 160 mm next , we repeated this dip fitting with dust scattering terms added to the above best - fit models , so that @xmath89 where @xmath90 is the source dip intensity and @xmath91 is the non - dip intensity . the non - dip intensity consists simply of a blackbody plus a cut - off power law with galactic absorption , and @xmath90 is given by the equation above in which these emission components are subjected to progressive covering . the net model can be expressed in the simplified form : @xmath92 where ag represents galactic absorption , bb is the blackbody with absorption ab , cpl the cut - off power law and pcf the progressive covering fraction . thus , the dip intensity is reduced by the cumulative effect of dust scattering and photoelectric absorption at every level of dipping , whereas the intensity scattered towards the observer is constant depending only on the non - dip source level . the optical depth was set to the best value of 2.4 obtained from the radial fitting , and the energy dependence of @xmath40 set to @xmath43 . good fits were obtained to the non - dip and dip mecs spectra and the results are shown in table 2b and fig . 7 . although there is no significant improvement in @xmath93/dof compared with the model without dust scattering , the results including the effects of dust scattering are clearly preferable . it can be seen from table 2b that the progressive covering factor rises to 82% in the deep dip spectrum ( 2.04.0 count s@xmath6 ) , i.e. still not reaching 100% which must be due to incomplete absorption of the emission components . in fig . 7 the fits to the non - dip and 3 levels of dipping are shown , with the evolution of the blackbody and cut - off power law components shown separately . in the top left panel the total model including all components is shown together with the total halo component itself containing blackbody and cut - off power law contributions from the incident spectrum to scattering . firstly , it can be seen that the blackbody emission ( lower right ) is rapidly absorbed when the point - source becomes covered by the absorber , and is close to zero flux in the deep dip spectrum . the cut - off power law clearly displays progressive covering in that , in each spectrum , part of the spectrum at low energies is clearly unabsorbed corresponding to the uncovered part of an extended source , i.e. the accretion disk corona . the contribution of this unabsorbed part decreases as dipping deepens . in non - dip and shallow dipping this uncovered component dominates the spectrum below 5 kev . in medium dipping it is about equal to the halo contribution ( at @xmath03 kev ) , and in deep dipping the halo is larger than the uncovered emission below about 4.5 kev . however , in addition to emission uncovered by the absorber envelope , the blobbiness of the absorber demonstrated by the fast variability in dipping will also prevent dipping reaching 100% . between the blobs , a fraction of the comptonized emission from the adc will be transmitted . these results are consistent with the results obtained from _ exosat _ by cbc95 , who found in dipping there was strong absorption of the blackbody with weaker absorption of the comptonized emission . having available a set of dip spectra in the present work , not just one dip spectrum , the existence of the unabsorbed emission is revealed and the fact that progressive covering takes place . we have shown that spectral evolution in dipping in is well - described by progressive covering of a two - component model which assumes that x - ray emission consists of point - like blackbody emission from the neutron star plus extended comptonized emission from an adc . the 130 kev luminosity of the source is @xmath94 erg s@xmath6 , for a distance of 15@xmath95 kpc ( christian & swank 1997 ) , a substantial fraction of the eddington limit , and the source is the most luminous of the dipping lmxb . the bolometric blackbody luminosity is @xmath95 erg s@xmath6 , corresponding to a blackbody radius @xmath96 of 8.3 km . if it is assumed that the emission region is an equatorial region on the neutron star in the plane of the accretion disk ( a sphere intersected by two planes ) , the half - height of the region _ h _ calculated using the expression @xmath97 , where @xmath98 is the radius of the neutron star ( assumed to be 10 km ) , is 6.8@xmath99 km . thus the blackbody emission is from a large fraction of the stellar surface . the half - height _ h _ of the radiatively - supported inner disk calculated from the luminosity of the source is [email protected] km , in agreement with the half - height of the emission region . these results were included in a larger sample of 14 lmxb investigated using _ asca _ and ( church & bauciska - church 2000 ) , in which approximate agreement is found between _ h _ and _ h _ over more than 3 decades in either parameter . this provides strong evidence that the neutron star and not the accretion disk is the source of blackbody emission in lmxb . our spectral fitting supports the point - like nature of the blackbody emission and the extended nature of the comptonized emission . the source joins the group of other dipping sources having an unabsorbed component in dipping which are well described by this combination of emission model with a progressive covering absorption model ( church et al . 1997 , 1998a , b ; bauciska - church et al . the only sources not tested with this model were x1746 - 371 and xb1254 - 690 , but it has been shown that _ asca _ data on these two sources are well fitted by the model ( church et al . in preparation ) . it thus appears that _ all _ of the dipping lmxb may be explained by this combination of emission model and description of covering during dips . is complicated by the dust - scattered halo . adding halo terms to the spectral model for dip spectra showed that the covering fraction for the extended hard emission rose to @xmath082% while modelling without the halo gave a maximum fraction less than 50% . spectral modelling with halo terms also showed that in shallow and medium dipping the unabsorbed comptonized emission dominates the low energy spectrum , but in deeper dipping the halo becomes dominant at low energies . in the deepest dip spectrum , the halo exceeds the uncovered comptonized emission below 4.5 kev . angelini et al . ( 1997 ) in an analysis of _ asca _ data also used the x - ray image to estimate the extent of the halo , and suggested that the halo could explain the soft excess in dip spectra . the present work shows that the halo dominates in deepest dipping , but in less deep dipping the uncovered comptonized emission of the adc is the major origin of the soft excess . we have modelled the radial intensity distribution function in several energy bands to obtain the halo fraction in these bands , and also the optical depth to dust scattering at 1 kev which was found to be @xmath40 = [email protected] . this value is larger than for any of the sources studied by predehl & schmitt ( ps95 ) , and the halo has appreciable effect on the the dip spectra . it is not sensible to regard dust parameters obtained from the modelling as providing definitive information on interstellar dust , since the radial modelling does not depend sensitively on the dust model used . dipping allows us to estimate the size of the adc from dip ingress times . the fast variability on timescales of is clearly associated with individual blobs of absorber covering the point - source blackbody and so is unrelated to the size of the adc . however , other observations of the source have consistently shown extended , relatively shallow shoulders to the deep dipping which we can identify with the extended emission region being progressively covered by the absorber . this is just detectable in fig . 1 . using the _ exosat _ observation and the _ rxte _ observation of sept . 1999 ( smale et al . in preparation ) , we estimate an average ingress time for this slow modulation of 12500@xmath92000 s. the dip ( shoulder ) ingress time @xmath100 is the time taken for the bulge in the outer disk to cross the diameter of the x - ray emitting adc , and is obtained via the velocity of the outer disk given by @xmath101 where _ p _ is the orbital period . using a period of 20.87 hr and a mass of the neutron star of 1.4@xmath102 we derive an accretion disk radius ( frank et al . 1987 ) of @xmath103 cm and thus a radius of the adc of @xmath104 cm . it is remarkable that in the case of this source , the adc extends to @xmath050% of the accretion disk radius , compared with @xmath010% in xb1916 - 053 and xb1323 - 619 ( church et al . 1998b ; bauciska - church et al . 1999 ) . however , given that the luminosity is @xmath105 10 times higher in it is not surprising that the adc , probably formed by evaporation by the central source and the adc itself , extends to much larger radii . in summary , we have completed an x - ray study of using _ bepposax_. we have obtained an improved orbital period of @xmath106 hr and made the first discovery of interdipping . we have investigated the depth of dipping in several energy bands and carried out modelling of the radial intensity distribution to obtain the halo fraction at several energies . from these data , the optical depth to scattering was derived , and an approximate @xmath43 dependence of the optical depth confirmed . spectral fitting results for the broadband non - dip spectrum are presented , and including a halo component in spectral fitting we have shown that spectral evolution is entirely consistent with progressive covering of blackbody emission from the neutron star and extended comptonized emission from the adc .

we present results of a study of the luminous dipping low mass x - ray binary made using _ bepposax_. an interval of deep and rapidly varying dipping was included in the observation . the radial intensity profile of the source obtained using the mecs instruments revealed excesses in intensity above the instrument point spread function below @xmath05 kev demonstrating the presence of a dust - scattering halo . from modelling of the radial profile in several energy bands , halo intensity fractions rising to 30% in the lowest band 2.53.5 kev were obtained . from these data , the optical depth to dust scattering at 1 kev was found to be @xmath1 . the non - dip spectrum of in the energy band 1100 kev is shown to be well - described by the emission model consisting of point - like blackbody radiation assumed to be from the neutron star plus extended comptonized emission from an adc . the blackbody temperature was @xmath2 kev and the comptonized emission had photon power law index @xmath3 and cut - off energy @xmath012 kev . the spectra of several dip levels were shown to contain an unabsorbed component below 5 kev . good fits to the dip spectra were obtained by allowing the comptonized emission to be progressively covered by an extended absorber while the blackbody was rapidly absorbed and a constant halo component accounted for dust scattering into the line - of - sight . it is shown that the unabsorbed component consists of the uncovered part of the comptonized emission plus a halo contribution which in deepest dipping dominates the spectrum below 4.5 kev . from the dip ingress time , we have derived a diameter of the extended comptonized emission region of @xmath4 cm , consistent with a hot , x - ray emitting corona extending to @xmath050% of the accretion disk radius . the source luminosity for a distance of 15 kpc is @xmath5 erg s@xmath6 , an appreciable fraction of the eddington limit making the most luminous dipping lmxb . the half - height of the blackbody emitting region on the neutron star of @xmath7 km agrees with the half - height of the radiatively supported inner accretion disk of @xmath8 km , which together with similar agreement recently obtained for 13 other lmxb strongly supports the identification of the neutron star as the origin of the blackbody emission in lmxb . finally , from _ rxte _ asm data , we derive an improved orbital period of [email protected] hr .

Paris Hilton's Brother Arrested for Going Berserk On Plane 'I Will F**king Own You Peasants' Paris Hilton's Brother -- Arrested for Going Berserk On Plane ... 'I Will F**king Own You Peasants' EXCLUSIVE Paris Hilton's younger brother Conrad Hilton was just arrested in L.A. for allegedly going insane on an international flight back in July ... and getting violent with flight attendants ... TMZ has learned. According to officials, multiple witnesses on the plane say the 20-year-old went berserk on a flight from London to L.A. ... and began screaming and threatening flight attendants. According to witnesses, Conrad was heard yelling the following things during his meltdown: -- "If you wanna square up to me bro, then bring it and I will f*cking fight you." -- "I am going to f*cking kill you." -- "I will f*cking rip through you." -- "I will f*cking own anyone on this flight; they are f*cking peasants." Witnesses say ... at one point during the flight, Conrad was ferociously punching the bulkhead of the plane ... 10 centimeters from a flight attendant's face. Witnesses also say they could smell weed seeping out of the bathroom ... and believe Hilton was the culprit. Conrad was allegedly so out of control, children on the plane were crying. At one point, Conrad fell asleep ... and the captain authorized crew members to restrain him to his seat for the descent. Conrad was ultimately handcuffed to his seat. Witnesses told officials Conrad grabbed a flight attendant's shirt and said, "I could get you all fired in 5 minutes. I know your boss! My father will pay this out. He has done it before. Dad paid $300k last time." According to documents obtained by TMZ, Hilton admitted to taking a sleeping pill before the flight and then bragged that he "buried" the flight attendants. "I told all of them I could get all of their jobs taken away in less than 30 seconds." We just spoke with Hilton's attorney Robert Shapiro -- yes, that Robert Shapiro -- who confirms Conrad took a sleeping pill before the flight and he wasn't himself. Shapiro says there are numerous news reports and cases of people experiencing adverse effects, including aggressive outbursts ... and he's suggesting that's what happened here. ||||| These crawls are part of an effort to archive pages as they are created and archive the pages that they refer to. That way, as the pages that are referenced are changed or taken from the web, a link to the version that was live when the page was written will be preserved.Then the Internet Archive hopes that references to these archived pages will be put in place of a link that would be otherwise be broken, or a companion link to allow people to see what was originally intended by a page's authors.The goal is to fix all broken links on the web . Crawls of supported "No More 404" sites. ||||| Who's your favorite Hilton? Decreasingly famous Paris? "Entrepreneur" Nicky? What's that, you don't have a fave? You do now. It's their brother, 20-year-old Conrad Hughes Hilton III. Why? Because he's bringing back old-timey words. Like "fracas." And "peasant." The younger Hilton sibling surrendered to the FBI Tuesday after being charged with "assaulting and intimidating several flight attendants aboard a British Airways flight from London to Los Angeles" in late July. The Telegraph reports that according to a 17-page affidavit, witnesses said Conrad claimed, "I will f_cking own anyone on this flight; they are f_cking peasants" and complained that another passenger was giving him the "stink eye." He also reportedly announced, "I could get you all fired in five minutes. I know your boss. My father will pay this out. He has done it before. Dad paid $300,000 last time." His father is Hilton & Hyland chairman and co-founder Rick Hilton. Mr. Conrad also reportedly spent time in a bathroom "where the smell of cannabis began emanating," punched the bulkhead and was so disruptive that children on the plane began to cry. Ninety minutes before the plane finally landed, he fell asleep and was handcuffed. You go, person who was born into incredible wealth! You show the world how a person like you does it when he flies commercial! Go big or go Economy Class! Hilton is now charged with "interfering with a flight crew," and could face up to 20 years in prison. He is currently free on $100,000 bail, which, if his previous alleged boast about how much his father has shelled out for him is true, seems like a relative bargain. Hilton's attorney, O.J. Simpson defender Robert Shapiro, said that the outburst "may be the effects of a sleeping pill." TMZ says that in documents it has obtained, Hilton admitted he'd taken a sleeping pill prior to the flight and that "I told all of them I could get all of their jobs taken away in less than 30 seconds." In 2012, Hilton allegedly entered a rehab facility after reportedly crashing into a parked car, but left early. At the time of the incident, neighbors claimed he told them, "See this bracelet. It costs $11,000. I can pay for everything." TMZ reported Tuesday that following that bad July flight, "Conrad voluntarily checked into a 30-day inpatient drug and alcohol treatment program," but he was involved in another car crash last August – less than a month after the incident. A California police officer told the Desert Sun at the time that several motorists had complained of "reckless driving." The witness accounts of Mr. Hilton's behavior and words have echoes of the notorious case of Ethan Couch – the Texas teen who in 2013 struck and killed four pedestrians and whose defense argued that he'd been the victim of affluenza. He's a young man who by multiple accounts seems to equate having money – sorry, I mean, his dad having money – with a pass to do whatever he likes. He's a fellow who apparently believes the world is full of people like him, and peasants. The unique thing about him is that he actually allegedly said it out loud. In front of many people. You've got to hand it to him for the honesty. If what he's charged with went down as described, Mr. Hilton certainly sounds like a person struggling with far deeper issues than dissatisfaction with the service on his flight. And if that's the case, I hope for his sake and the sake of everyone he comes into contact with, especially on the road, that he can get help and make it stick. I also appreciate a good self-revealing bozo. It's refreshing when someone can apparently just come out and be that brazenly contemptuous of the rules of a civilization, and the little people who inhabit it. It's a little window into how such a person must have been raised. I wouldn't want to be trapped in a plane with you, Conrad Hilton, but I do have to share a world with you, and it's great you're not even pretending to have anything but hatred for the rest of us.

– We haven't heard much about Paris Hilton lately, but fear not: little brother Conrad Hilton is here to misbehave in her place. The 20-year-old surrendered to the FBI yesterday over charges that he assaulted and intimidated flight attendants on a British Airways flight from London to LA in July. Prosecutors say Hilton became disruptive and appeared to be on drugs, pacing the aisles, blocking flight attendants and throwing a fist toward one, punching the bulkhead, accusing a passenger of giving him the "stink eye," and causing frightened children to cry as he screamed profanities. Among the charming things he allegedly yelled, per the Los Angeles Times and TMZ: "I will f---ing own anyone on this flight; they are f---ing peasants." "I could get you all fired in five minutes. I know your boss. My father will pay this out, he has done it before. Dad paid $300,000 last time." "If you wanna square up to me bro, then bring it and I will f---ing fight you." "I am going to f---ing kill you." "I will f---ing rip through you." After two safety briefings, crew members were finally able to handcuff Hilton to his seat while he was asleep; upon waking, he allegedly continued to yell obscenities until police came onboard. All that's being reported of Hilton's side so far is that he told investigators he was defending himself and that he "told all of them I could get all of their jobs taken away in less than 30 seconds." His attorney says he had taken a sleeping pill before the flight, and it must have had unanticipated side effects. Passengers also claimed to have smelled marijuana coming from the bathroom. Hilton has been charged with interfering with a flight crew and faces up to 20 years in prison, the Telegraph reports; he's been released on bail. Salon notes that Hilton went into rehab in 2012 after crashing into a parked car, but didn't complete the program; he also reportedly did 30 days of rehab after the July flight. (Click for more celebrities behaving badly on planes.)

SECTION 1. SHORT TITLE. This Act may be cited as the ``Transportation and Logistics Hiring Reform Act''. SEC. 2. DEFINITIONS. In this Act: (1) Entity.--The term ``entity'' means a person acting as-- (A) a shipper or a consignee; (B) a broker, a freight forwarder, or a household goods freight forwarder (as such terms are defined in section 13102 of title 49, United States Code); (C) a non-vessel-operating common carrier, an ocean freight forwarder, or an ocean transportation intermediary (as such terms are defined in section 40102 of title 46, United States Code); (D) an indirect air carrier authorized to operate under a Standard Security Program approved by the Transportation Security Administration; (E) a customs broker licensed in accordance with section 111.2 of title 19, Code of Federal Regulations; (F) an interchange motor carrier subject to paragraphs (1)(B) and (2) of section 13902(i); or (G) a warehouse (as defined in Article 7-102(13) of the Uniform Commercial Code). (2) Motor carrier.--The term ``motor carrier'' means a motor carrier or a household goods motor carrier (as such terms are defined in section 13102 of title 49, United States Code) that is subject to Federal motor carrier financial responsibility and safety regulations. (3) State.--The term ``State'' means each of the 50 States, a political subdivision of any such State, any intrastate agency, any other political agency of 2 or more States, the District of Columbia, American Samoa, the Commonwealth of the Northern Mariana Islands, the Commonwealth of Puerto Rico, Guam, and the Virgin Islands. SEC. 3. NATIONAL HIRING STANDARDS FOR MOTOR CARRIERS. (a) National Standard.--Before tendering a shipment, but not more than 35 days before the pickup of a shipment by the hired motor carrier, an entity shall verify that the motor carrier, at the time of such verification-- (1) is registered with and authorized by the Federal Motor Carrier Safety Administration to operate as a motor carrier or household goods motor carrier, if applicable; (2) has the minimum insurance coverage required by Federal law; and (3)(A) before the safety fitness regulations are issued pursuant to subsection (c), does not have an unsatisfactory safety fitness rating issued by the Federal Motor Carrier Safety Administration in force at the time of such verification; or (B) after the safety fitness regulations are issued pursuant to subsection (c), does not have a safety fitness rating issued by the Federal Motor Carrier Safety Administration under such regulations that is the equivalent of the unsatisfactory fitness rating referred to in subparagraph (A). (b) Intended Use of Data.-- (1) In general.--Only evidence of an entity's compliance with subsection (a) may be admitted as evidence or otherwise used in a civil action for damages resulting from a claim of negligent selection or retention of such motor carrier against the entity. (2) Excluded evidence.--All other motor carrier data created or maintained by the Federal Motor Carrier Safety Administration including safety measurement system data or analysis of such data, may not be admitted into evidence in a case or proceeding in which it is asserted or alleged that an entity's selection or retention of a motor carrier was negligent. (c) Rulemaking.-- (1) In general.--Not later than 18 months after the date of the enactment of this Act, the Secretary of Transportation shall promulgate safety fitness determination regulations that update and revise the standards for establishing an unsatisfactory safety rating for motor carriers. (2) Factors for an unsatisfactory rating.--In the regulations promulgated pursuant to paragraph (1), the Secretary shall determine if a motor carrier is not fit to operate a commercial motor vehicle in or affecting interstate commerce in accordance with section 31144 of title 49, United States Code. (d) Compliance With All Safety Laws.--All commercial carriers shall comply with all applicable Federal laws pertaining to safety. SEC. 4. APPLICABILITY AND EFFECTIVE DATE. Notwithstanding any other provision of law, this Act shall apply with respect to any action commenced on or after the date of the enactment of this Act without regard to whether the harm that is the subject of the action, or the conduct that caused the harm, occurred before such date of enactment.

Transportation and Logistics Hiring Reform Act This bill establishes a national hiring standard for motor carriers. The bill defines an"entity" as a person acting as: a shipper or a consignee; a broker, a freight forwarder, or a household goods freight forwarder; a non-vessel-operating common carrier, an ocean freight forwarder, or an ocean transportation intermediary; an indirect air carrier authorized to operate under a Standard Security Program approved by the Transportation Security Administration; a federally licensed customs broker; an interchange motor carrier; or a warehouse. Before tendering a shipment, but not more than 35 days before the pickup of a shipment by the hired motor carrier, an entity shall verify that the carrier: is registered with and authorized by the Federal Motor Carrier Safety Administration (FMCSA) to operate as a motor carrier or household goods motor carrier; has the minimum insurance coverage required by federal law; and does not have an unsatisfactory safety fitness rating issued by the FMCSA. Only evidence of an entity's compliance with this Act may be admitted as evidence in a civil action for damages resulting from a claim of negligent selection or retention of such motor carrier against the entity. No other motor carrier data created or maintained by the FMCSA, including safety measurement system data or analysis of such data, may be admitted in a case or proceeding in which it is asserted or alleged that an entity's selection or retention of a motor carrier was negligent. The Secretary of Transportation shall promulgate safety fitness determination regulations that update and revise the standards for establishing an unsatisfactory safety rating for motor carriers. In the regulations promulgated, the Secretary shall determine if a carrier is not fit to operate a commercial motor vehicle in or affecting interstate commerce. All commercial carriers shall comply with all applicable federal laws pertaining to safety.

methods for measuring sap flow in trees have led to physiological discoveries at the individual level as well as better estimates of water use at the stand level . at the organismal level , data on sap flow have helped estimate whole tree hydraulic conductances ( domec et al . , 2010 , p. 1941 ; wullschleger et al . , 1998 , p. 1662 ) , usage of stored water by trees ( phillips et al . , 1997 ; goldstein et al . , 1998 ; meinzer et al . , 2004 ) , evidence of night - time transpiration ( daley and phillips , 2006 ; moore et al . , 2008 ; oishi et al . , 2008 ) , hydraulic limitations in tall trees ( schfer et al . , 2000 ; barnard and ryan , 2003 ; magnani et al . , 2008 ) , and patterns of water use throughout the day and throughout the growing season ( granier , 1987 ; granier et al . , 2000 ) . likewise , to separate the physical and biological controls on water flow rates in forests , it is essential to incorporate sap flow measurements into the repertoire of ecological measurements in ecosystem studies ( kstner et al . , 1998 ; sap flow rates measured in representative individuals can be scaled up to estimate stand transpiration throughout the growing season ( goulden and field , 1994 ) as well as stand carbon assimilation rates ( schfer et al . sap flow measurements also perform well in locations that have complex terrain , variable topography , or in constrained areas where eddy covariance is not well suited ( wilson et al . , 2001 ) . various methods have been put forth to continuously measure sap flow rates in trees including heat application with infrared imaging ( tributsch et al . , 2006 ; helfter et al . , 2007 ) , geophysical methods ( al hagrey , 2007 ) , and magnetic resonance imaging techniques ( homan et al . , 2007 ) . but , by far , the most common techniques involve using heat as a tracer for sap flow ( daum , 1967 and reviewed by smith and allen , 1996 ) including the use of heat pulse ( marshall , 1958 ; swanson and whitfield , 1981 ) and heat ratios ( burgess et al . , 1998 ) , thermal dissipation ( td ) probes ( granier , 1987 ) and the tissue heat balance ( thb , cermk et al . , 1973 , 2004 ) , and stem heat balance ( sakuratani , 1981 ; baker and van bavel , 1987 ) techniques . many studies employ the td method because of its ease of use , affordability , and predictable power consumption ( kstner et al . , 1996 , 1998 ; smith and allen , 1996 ; wullschleger et al . , 1998 ) when compared with the other heat tracer techniques . the td method has been shown to match well with various independent methods for measuring water use in trees including values obtained by the penman monteith equation ( granier , 1987 ) , porometry measurements on the leaves ( zhang et al . , 1997 ) , measurements of above- and below - canopy evaporation ( diawara et al . , 1991 ) , whole tree gas exchange chambers ( goulden and field , 1994 ) , and gravimetric water loss methods ( granier et al . , however , caution needs to be taken when interpreting signals from td sensors due to possible night - time recharge and/or transpiration ( lu et al . , 2004 ; variability in flow rates across the sensor length ( wullschleger et al . , 1998 ; clearwater et al . , 1999 ; lu et al . , 2004 ) , or sensors being partially located in non - conducting tissue ( clearwater et al . , 1999 ; lu et al . , 2004 ; taneda and sperry , 2008 ; bush et al . , 2010 ; hultine et al . , the latter is most commonly encountered in ring - porous tree species where the earlywood vessels of the most newly formed growth ring perform the majority of the transport . ( 1999 ) developed a correction for this situation , however it can not be used when the proportion of non - conducting tissue greatly exceeds that of the conducting tissue along the sensor length ( bush et al . recently , researchers who have calibrated td sensors in ring - porous species and some diffuse porous species have reported new coefficients for the multiplier ( i.e. , 119 in the original equation ) that are twice as large ( hultine et al . , 2010 ) to almost an order of magnitude larger ( taneda and sperry , 2008 ) , to two orders of magnitude larger ( bush et al . , 2010 ) . these recent calibrations of td sensors in ring - porous species call into question the applicability of the original calibration in these species as well as previous studies in ring - porous species that have used the original calibration . these laboratory calibrations give the advantage of a controlled environment , but they involve destructive sampling of large trees ( which may not be feasible ) or the use of branches ( bush et al . , 2010 ) . likewise , if positive pressure is used in laboratory calibrations , the driving force for water flow will differ from the negative pressures that trees experience to move water against gravity and the frictional resistance of the conduits . therefore , another validation of td sensors in the trunks of ring - porous species under natural conditions is necessary . the use of the thb method to calibrate td sensors gives the advantage of providing an in situ relationship under natural ranges of flow rates and transpirational driving forces . this is especially important in the oak - dominated forests of the new jersey pine barrens because its sandy soils mean that trees grow very slowly and therefore have very shallow sapwood depths which are problematic to td sensors . the thb method has also been shown to match well with transpiration rates from willow trees ( salix viminalis l. ) measured using an open - top ventilated chamber with an infrared gas analyzer ( cienciala and lindroth , 1995 ) and in two conifer species [ larix sp . and picea abies ( ( l.)h.karst . ) ] where transpiration rates were estimated using porometer measurements of leaves ( schulze et al . , 1985 ) . likewise , since the thb method integrates sap flow across a radial profile ( cermk et al . , 2004 ) it was found to be appropriate even when flow occurred in one third of the radial heater depth ( tatarinov et al . , therefore , our objective is to measure sap flow rates using both td and thb sensors in the same trees and compare the results to determine the validity of the original granier calibration in ring - porous oaks of the new jersey pine barrens . because the thb method calculates sap flow rates based on an energy balance of a specified volume of wood tissue and the specific heat of water , it requires no calibration ( lundblad et al . , 2001 ) this contrasts with the td method in which flow is based on an empirical equation . ( 2004 ) suggest that it is appropriate to use the thb method in new calibrations of the td method . it is recognized that neither method can be considered to be free from error or bias , however a cross - validation is still valuable with thb as a base measurement because it is based on physical properties of energy balance as well as being an in situ method of calibration . this research is important because different estimates of tree and stand transpiration rates ( depending on the measurement technique ) will have different implications for land and water management strategies . specifically , comparison of both sap flow techniques in slow - growing , ring - porous species like the oak - dominated forests of the new jersey atlantic coastal region will inform ecohydrologic studies in similar regions where ring - porous species dominate and have proven difficult to estimate sap flow rates accurately with the td method . this study was conducted at the rutgers university pinelands research station , located in pemberton township in the pine barrens of southern new jersey , usa ( n 39550 , w 74360 ) during the growing season of 2009 ( from 15 may to 1 october ) and 2010 ( from 26 june to 24 august ) when the majority of sensors were functional . mean annual temperature is 11.5c , with an annual precipitation of 1123 ( se = 182 ) mm . during 2010 , the site experienced a severe drought with soil moisture contents falling to as low as 2.6% . droughts in this region are exacerbated by the fact that the soil is a sandy podzol ( rhodehamel , 1998 ) with low nutrient content and field capacity . the study area is relatively flat with a mean elevation of 33 m a.s.l . in order to compare both sap flow methods , the thb method ( cermk et al . , 1973 ) and the td method ( granier , 1987 ) , trees were chosen that were representative of the species and size distribution of the stand and large enough to host both sap flow systems . therefore , both systems were installed in four mature individuals of q. prinus , two q. velutina , and one p. rigida ( table 1 ) . biometric data for trees receiving tissue heat balance ( thb ) and thermal dissipation ( td ) sensors . years of measurement for each sensor type are also included and azimuth locations of the sensors in the trees are reported in parentheses . tissue heat balance sensors consisted of three heated electrodes that are 4 cm long and receive between 40 and 200 ma of current and one unheated electrode . the power supplied to the system varies in relation to the sap flow rate to keep the temperature difference between the heated and reference electrodes at 1c ( ems brno ; brno , czech republic ) . thb electrodes were inserted at a height of between 1.3 and 1.5 m above the ground . to install the electrodes , some of the bark was removed and the bark / phloem thickness determined using a gauge supplied with the system ( ems brno ; brno , czech republic ) . next , the electrodes were hammered into the trunk using an insertion tool supplied with the system and making sure that the insulation on the electrodes covered the phloem and bark layer . electrodes were installed to a depth that encompassed the entire sapwood of the quercus individuals . in the pinus individual , the thb sensors were inserted 3.5 cm deep covering most of the sapwood depth . reflective polyethylene foam covers provided by the manufacturer ( ems brno ; brno , czech republic ) were then placed over the electrodes to prevent temperature fluctuations from sunflecks . power ( p in watts ) being applied to electrodes was recorded every 30 s and 30 min averages were stored in a system data logger ( model p4.2 , ems brno ; brno , czech republic ) . sap flow rates were calculated using the following equation : where q is the sap flow rate in kg h cm stem circumference , cw is the specific heat of water ( j kg k ) , d is the circumferential distance being covered by the electrodes ( cm ) , t ( k ) is the temperature difference between heated and unheated electrodes and z / cw represents the heat loss from the system determined under the zero flow ( night - time ) conditions where it is assumed that no sap is flowing and therefore any heat lost from the system is due to conduction through the wood tissue . data from the data logger were converted to sap flow ( kg h ) using system software ( mini32 version 4.1.5.0 ; ems brno ; brno , czech republic ) , scaled up to the tree level by multiplying half - hourly values by the stem circumference ( minus bark and phloem ) and then integrating to yield daily values ( kg day ) . individuals that received the thb system were also given 2-cm long , td sensors ( granier , 1987 ) . in 2010 , two q. prinus individuals and one q. velutina were also fitted with 1-cm long td sensors to compare sensor lengths ( table 1 ) . data from both the 2 and 1-cm td sensors for the q. velutina individual was also included for the beginning of the 2011 growing season ( may 1st to june 10th ) . the pinus individual also received a sensor at a depth of 24 cm at the beginning of the 2010 growing season to test for radial patterns in sap flow ( phillips et al . , 1996 ) . td sensors consist of a pair of hypodermic needles each containing a copper - constantan thermocouple . one of the sensors in the pair is also equipped with a constantan heating wire wrapped around the needle to which a constant power of 0.2 w ( 0.1 w for 1-cm long sensors ) was applied . after the bark and phloem were removed , both needles of the sensor pair were inserted radially into the boles of the trees at about 1.3 m above ground . the upper , heated sensor was placed about 10 cm above the unheated , reference sensor , and placed in an aluminum tube with heat conductivity paste to enhance heat transfer between the sapwood and the probes . an aluminum bread pan was placed over each sensor pair to reduce temperature gradients from solar radiation . the td technique estimates sap flow rates by measuring the temperature difference between the heated and reference sensors . water flowing past the heated sensor dissipates some of the heat and decreases the temperature difference between the sensors . a time of zero flow and maximal temperature difference acts as a baseline for the data and usually occurs around predawn . sensors were attached to a campbell scientific cr3000 data logger and am16/32a multiplexer ( logan , ut , usa ) and data was logged every 30 s with averages stored every 30 min . raw data were converted to sap flow rates ( js ; kg m s ) using granier s original calibration equation : where tmax is the temperature difference between probes when no water is flowing and t is the temperature difference when sap flow is occurring . to confirm that tmax values were chosen when sap flow was zero , we used the constraints developed by oishi et al . specifically , tmax values were chosen when vpd < 0.05 kpa over a 2-h period to avoid times of nocturnal transpiration and t values were stable over a 2-h period to avoid times of nocturnal recharge . we also performed a correction in the oak species to account for the fact that the sensors were longer than the sapwood depth ( clearwater et al . , 1999 ) as follows : where sd is the sapwood depth ( cm ) and ls is the sensor length ( cm ) . ( reported in table 1 ) for each of the quercus study individuals were estimated by coring 12 representative quercus individuals varying in size and species throughout the stand and visually identifying the transition from sapwood to heartwood as the color change from wet to dry wood . we then developed a relationship ( r = 0.60 , p < 0.0001 ) between dbh and sapwood depth as follows : these quercus individuals grow very slowly , therefore this depth represents several growth rings . the sapwood depth of the pinus individual was estimated using a tree core of that individual and visually identifying the sapwood depth via a color change between wet and dry wood . to compare data with the thb system , sap flow data from the td system needed to be scaled up from a per unit area basis to the entire bole area by multiplying by the sapwood area ( m ) . likewise , to compare both systems more broadly , plot level estimates of transpiration were calculated using either the thb or td sap flow data for all trees greater than 2 cm dbh in a 3014-m plot area . to begin , the dbh and species of all trees > 2.5 cm dbh within the plots were recorded . only 2009 data were included since the thb system did not have a large enough sample size in 2010 . all sensored individuals were included in the analysis ( not only trees that contained both systems ) which yielded seven q. prinus , nine q. velutina , three q. coccinia , and one p. echinata individuals where td sap flow was measured and four q. prinus , one q. velutina , and one p. echinata where thb sap flow was measured . averages of sap flow in q. prinus and q. velutina were used to estimate flow rates in q. alba , q. stellata , and q. coccinia for the thb system . , in addition , the q. prinus 2-cm td data were rescaled with the equation from the 1-cm data from 2010 . average sap flows for each species were multiplied by the sapwood area of each species , divided by the plot area and scaled up to daily values to yield transpiration values in mm day . this study was conducted at the rutgers university pinelands research station , located in pemberton township in the pine barrens of southern new jersey , usa ( n 39550 , w 74360 ) during the growing season of 2009 ( from 15 may to 1 october ) and 2010 ( from 26 june to 24 august ) when the majority of sensors were functional . mean annual temperature is 11.5c , with an annual precipitation of 1123 ( se = 182 ) mm . during 2010 , the site experienced a severe drought with soil moisture contents falling to as low as 2.6% . droughts in this region are exacerbated by the fact that the soil is a sandy podzol ( rhodehamel , 1998 ) with low nutrient content and field capacity . the study area is relatively flat with a mean elevation of 33 m a.s.l . in order to compare both sap flow methods , the thb method ( cermk et al . , 1973 ) and the td method ( granier , 1987 ) , trees were chosen that were representative of the species and size distribution of the stand and large enough to host both sap flow systems . therefore , both systems were installed in four mature individuals of q. prinus , two q. velutina , and one p. rigida ( table 1 ) . biometric data for trees receiving tissue heat balance ( thb ) and thermal dissipation ( td ) sensors . years of measurement for each sensor type are also included and azimuth locations of the sensors in the trees are reported in parentheses . tissue heat balance sensors consisted of three heated electrodes that are 4 cm long and receive between 40 and 200 ma of current and one unheated electrode . the power supplied to the system varies in relation to the sap flow rate to keep the temperature difference between the heated and reference electrodes at 1c ( ems brno ; brno , czech republic ) . thb electrodes were inserted at a height of between 1.3 and 1.5 m above the ground . to install the electrodes , some of the bark was removed and the bark / phloem thickness determined using a gauge supplied with the system ( ems brno ; brno , czech republic ) . next , the electrodes were hammered into the trunk using an insertion tool supplied with the system and making sure that the insulation on the electrodes covered the phloem and bark layer . electrodes were installed to a depth that encompassed the entire sapwood of the quercus individuals . in the pinus individual , the thb sensors were inserted 3.5 cm deep covering most of the sapwood depth . reflective polyethylene foam covers provided by the manufacturer ( ems brno ; brno , czech republic ) were then placed over the electrodes to prevent temperature fluctuations from sunflecks . power ( p in watts ) being applied to electrodes was recorded every 30 s and 30 min averages were stored in a system data logger ( model p4.2 , ems brno ; brno , czech republic ) . sap flow rates were calculated using the following equation : where q is the sap flow rate in kg h cm stem circumference , cw is the specific heat of water ( j kg k ) , d is the circumferential distance being covered by the electrodes ( cm ) , t ( k ) is the temperature difference between heated and unheated electrodes and z / cw represents the heat loss from the system determined under the zero flow ( night - time ) conditions where it is assumed that no sap is flowing and therefore any heat lost from the system is due to conduction through the wood tissue . data from the data logger were converted to sap flow ( kg h ) using system software ( mini32 version 4.1.5.0 ; ems brno ; brno , czech republic ) , scaled up to the tree level by multiplying half - hourly values by the stem circumference ( minus bark and phloem ) and then integrating to yield daily values ( kg day ) . individuals that received the thb system were also given 2-cm long , td sensors ( granier , 1987 ) . in 2010 , two q. prinus individuals and one q. velutina were also fitted with 1-cm long td sensors to compare sensor lengths ( table 1 ) . data from both the 2 and 1-cm td sensors for the q. velutina individual was also included for the beginning of the 2011 growing season ( may 1st to june 10th ) . the pinus individual also received a sensor at a depth of 24 cm at the beginning of the 2010 growing season to test for radial patterns in sap flow ( phillips et al . , 1996 ) . td sensors consist of a pair of hypodermic needles each containing a copper - constantan thermocouple . one of the sensors in the pair is also equipped with a constantan heating wire wrapped around the needle to which a constant power of 0.2 w ( 0.1 w for 1-cm long sensors ) was applied . after the bark and phloem were removed , both needles of the sensor pair were inserted radially into the boles of the trees at about 1.3 m above ground . the upper , heated sensor was placed about 10 cm above the unheated , reference sensor , and placed in an aluminum tube with heat conductivity paste to enhance heat transfer between the sapwood and the probes . an aluminum bread pan was placed over each sensor pair to reduce temperature gradients from solar radiation . the td technique estimates sap flow rates by measuring the temperature difference between the heated and reference sensors . water flowing past the heated sensor dissipates some of the heat and decreases the temperature difference between the sensors . a time of zero flow and maximal temperature difference acts as a baseline for the data and usually occurs around predawn . sensors were attached to a campbell scientific cr3000 data logger and am16/32a multiplexer ( logan , ut , usa ) and data was logged every 30 s with averages stored every 30 min . raw data were converted to sap flow rates ( js ; kg m s ) using granier s original calibration equation : where tmax is the temperature difference between probes when no water is flowing and t is the temperature difference when sap flow is occurring . to confirm that tmax values were chosen when sap flow was zero , we used the constraints developed by oishi et al . specifically , tmax values were chosen when vpd < 0.05 kpa over a 2-h period to avoid times of nocturnal transpiration and t values were stable over a 2-h period to avoid times of nocturnal recharge . we also performed a correction in the oak species to account for the fact that the sensors were longer than the sapwood depth ( clearwater et al . , 1999 ) as follows : where sd is the sapwood depth ( cm ) and ls is the sensor length ( cm ) . sapwood depths ( reported in table 1 ) for each of the quercus study individuals were estimated by coring 12 representative quercus individuals varying in size and species throughout the stand and visually identifying the transition from sapwood to heartwood as the color change from wet to dry wood . we then developed a relationship ( r = 0.60 , p < 0.0001 ) between dbh and sapwood depth as follows : these quercus individuals grow very slowly , therefore this depth represents several growth rings . the sapwood depth of the pinus individual was estimated using a tree core of that individual and visually identifying the sapwood depth via a color change between wet and dry wood . to compare data with the thb system , sap flow data from the td system needed to be scaled up from a per unit area basis to the entire bole area by multiplying by the sapwood area ( m ) . likewise , to compare both systems more broadly , plot level estimates of transpiration were calculated using either the thb or td sap flow data for all trees greater than 2 cm dbh in a 3014-m plot area . to begin , the dbh and species of all trees > 2.5 cm dbh within the plots were recorded . only 2009 data were included since the thb system did not have a large enough sample size in 2010 . all sensored individuals were included in the analysis ( not only trees that contained both systems ) which yielded seven q. prinus , nine q. velutina , three q. coccinia , and one p. echinata individuals where td sap flow was measured and four q. prinus , one q. velutina , and one p. echinata where thb sap flow was measured . averages of sap flow in q. prinus and q. velutina were used to estimate flow rates in q. alba , q. stellata , and q. coccinia for the thb system . , in addition , the q. prinus 2-cm td data were rescaled with the equation from the 1-cm data from 2010 . average sap flows for each species were multiplied by the sapwood area of each species , divided by the plot area and scaled up to daily values to yield transpiration values in mm day . daily sap flow rates in q. prinus ranged from 1.4 to 34.2 kg day during 2009 and from 1.0 to 14.4 kg day in 2010 using td sensors and from 1.2 to 29.2 kg day in 2009 and from 1.2 to 16.2 kg day in 2010 using thb sensors ( figure 1 ) . in q. velutina , daily sap flow rates ranged from 1.3 to 28.2 kg day during 2009 and from 1.0 to 18.3 kg day in 2010 using td sensors and from 2.2 to 41.6 kg day in 2009 using thb sensors ( figure 2 ) . in p. echinata , daily sap flow rates ranged from < 1 to 100.4 kg day during 2009 and from < 1 to 108.1 kg day in 2010 using td sensors and from < 1 to 117.9 kg day in 2009 and from < 1 to 109.5 kg day in 2010 using thb sensors ( figure 3 ) . sap flow rates ( kg day ) for q. prinus derived from the tissue heat balance ( thb ) system and thermal dissipation ( td ) system using 2-cm long sensors for ( a ) a 16.8-cm dbh individual , ( b ) a 16.8-cm dbh individual , and ( c ) a 17.7-cm dbh individual . open symbols denote sap flow rates derived from the original granier equation and closed symbols are sap flow rates with the clearwater correction applied . circles denote flow rates measured in 2009 and triangles ( a ) denote flow rates measured in 2010 . the solid lines are the best fit regressions for ( a ) 2009 uncorrected data ( y = 0.72x 2.7 , r = 0.57 ) , 2009 clearwater - corrected data ( y = 1.58x 7.9 , r = 0.54 ) , 2010 uncorrected data ( y = 0.43x + 0.48 , r = 0.87 ) , 2010 clearwater - corrected data ( y = 0.82x + 0.42 , r = 0.86 ) , ( b ) 2009 uncorrected data ( y = 0.18x + 2.1 , r = 0.12 ) and 2009 clearwater - corrected data ( y = 0.66x + 0.65 , r = 0.43 ) , and ( c ) 2009 uncorrected data ( y = 0.38x + 0.04 , r = 0.48 ) and 2009 clearwater - corrected data ( y = 0.69x 0.87 , r = 0.46 ) . sap flow rates ( kg day ) derived from the tissue heat balance ( thb ) system and thermal dissipation ( td ) system using 2-cm long sensors in a 27.1-cm dbh q. velutina individual . the dashed line is the one to one line and the solid line is the best fit regression ( y = 1.24 x , r = 0.71 ) . sapwood depth was calculated to be over 2 cm therefore original 2-cm length sensor data are shown . sap flow rates ( kg day ) derived from the tissue heat balance ( thb ) system and thermal dissipation ( td ) system using 2-cm long sensors in a 36.3-cm dbh pinus echinata . td flow rates were corrected for radial variation by comparing data between 02 and 24-cm depth sensors . the closed circles denote data from 2009 and the open circles denote data from 2010 . the dashed line is the one to one line , the dotted lines are 95% confidence intervals around the best fit solid line ( y = 0.87x + 1.57 , r = 0.85 ) . two centimeter long td sensors tended to underestimate sap flow rates in the two oak species ( q. prinus and q. velutina ) compared with the thb system ( figures 1 and 2 ) . in q. prinus , td data with no clearwater correction were between 30 and 80% lower than data from the thb system . clearwater - corrected data more closely matched the thb data , but still underestimated flow rates by 2035% ( figures 1a c ) . in one q. prinus individual , clearwater - corrected td flow rates measured in 2009 were higher than those measured by the thb method ( figure 1a ) but were more similar to the trends of the other q. prinus individuals in 2010 . in q. velutina , the 2-cm long td sensors tended to underestimate flow rates compared to the thb method , with increasing underestimation ( of up to 50% ) at higher flow rates ( figure 2 ) . since this individual was calculated to have a sapwood depth that approximately equaled the td sensor length ( table 1 ) , no clearwater correction was applied to the data . in p. echinata , sap flow rates measured by the 2- to 4-cm depth sensor were about 0.6 times that of the outer 0- to 2-cm td sensor . with this radial correction applied to the data , sap flow rates measured with td sensors matched fairly well with those measured using the thb system with the fitted regression for the 2009 and 2010 data falling just slightly below the one to one line ( figure 3 ) . average underestimations of the td system compared with the thb system were about 9% ( se = 0.03 ) . in q. prinus , sap flow rates measured with 2-cm long td sensors matched those measured with 1-cm long sensors at low flow rates but were underestimated at higher flow rates ( figure 4a ) . applying the clearwater correction to the 2-cm sensor data caused a slight overestimation of the data compared with the 1-cm sensor data , however data were still underestimated at the highest sap flow rates ( figure 4a ) . on the other hand , in q. velutina , 1-cm td sensors consistently underestimated sap flow rates compared with the 2-cm sensors with even larger differences occurring when the clearwater correction was applied to the 2-cm sensor data ( figure 4b ) . using the equation fitted to the uncorrected q. prinus data in figure 4a , 2-cm td data were rescaled to the 1-cm sensor data and compared to trees that were also equipped with the thb system ( figure 5 ) . with this 1-cm sensor correction , the 2-cm td are no longer consistently underestimating sap flow rates relative to the thb data . the one to one line between the thb and td data tends to fall near or within the 95% confidence intervals of the best fit regression however there is a large amount of scatter in the relationship ( figure 5 ) . comparison of sap flow rates measured with 1 and 2-cm long thermal dissipation ( td ) sensors in ( a ) two q. prinus individuals ( circles 16.8 cm dbh , triangles 17.7 cm dbh individual ) and ( b ) a 19.5-cm dbh q. velutina individual ( circles 2010 data , triangles 2011 data ) . open symbols denote sap flow rates derived from the original granier equation and closed symbols are sap flow rates with the clearwater correction applied to the 2-cm long sensor data . the dashed lines are the one to one lines and the solid lines are the best fits for ( a ) uncorrected data ( y = 1.65 x , r = 0.63 ) and clearwater - corrected data ( y = 2.65 x , r = 0.65 ) and ( b ) uncorrected data ( y = 0.77x + 4.7 , r = 0.34 ) and clearwater - corrected data ( y = 1.13x + 6.5 , r = 0.34 ) . quercus prinus daily sap flow rates ( kg day ) derived from the tissue heat balance ( thb ) system compared with rates derived from 2-cm long thermal dissipation ( td ) sensors ( no clearwater correction applied ) that were scaled using data from 1-cm long td sensors ( figure 4 ) . the closed circles denote data from a 17.7-cm dbh individual , open circles denote data from a 16.8-cm dbh individual and the triangles denote data from a 16.8-cm dbh individual measured in 2009 ( closed ) and 2010 ( open ) . the dashed line is the one to one line , the solid line is the best fit regression(y = 1.15x 3.83 , r = 0.41 ) to the data and the dotted lines are the 95% confidence intervals around the linear regression . when plot level transpiration rates were estimated for 2009 using either the td sap flow data or the thb sap flow data values estimated from td data tended to match values estimated from thb at low flow rates but were underestimated at higher fluxes ( figure 6 ) likewise , underestimations were larger when the clearwater correction was applied than when 2-cm td sensors were corrected with 1 cm data ( figure 6 ) . the average underestimation of clearwater - corrected td data was about 24% ( se = 0.02 ) and about 15% ( se = 0.02 ) when 2-cm td sensor data were corrected with the 1-cm sensor equation . plot level estimates of daily transpiration ( mm day ) for 2009 derived from tissue heat balance ( thb ) sap flow data vs. estimates derived from thermal dissipation ( td ) sap flow data . closed circles denote td data with the clearwater correction applied to all quercus sp . and open circles denote td data where q. prinus 2-cm long sensors are corrected with 1-cm data regression ( figure 4a ) and all other quercus sp . received the clearwater correction . the dashed line is the one to one line , and the solid lines are the best fit regressions for the clearwater - corrected td data ( y = 0.66x + 0.13 , r = 0.43 ) and the 1-cm corrected td data ( y = 0.66x + 0.18 , r = 0.44 ) . we found that sap flow rates in two quercus sp . tended to be underestimated by the td system compared to the thb system the sap flow rates we found in the oak species using the thb method were between 1 and 5 kg h , which matched well with water absorption and heat pulse velocity rates measured in oaks ( 1.52 kg h ; granier et al . , 1994 ) as well as rates measured using heat field deformation ( 24 kg h ; poyatos et al . , 2007 ) the clearwater correction brought values closer to those measured by the thb system in q. prinus , but values still averaged 2035% lower . two centimeter long td sensors also underestimated flow rates relative to 1-cm long td sensors in q. prinus , more so at higher flow rates . when 2-cm td data were rescaled with data from the 1-cm long sensors , sap flow rates were no longer underestimated at high flow rates relative to the thb system . there is significant scatter in the relationship ( figure 5 ) , but this may be a product of the inherent within- and between - tree variability in sap flow which has been shown to vary by about 30% around the mean in the oaks at this site ( unpublished data ) . some variability may also be attributed to the estimation of sapwood depth in the oak species . determining the actual conducting area in these species is difficult without dye ascents and destructive sampling ( clearwater et al . likewise , the true conducting area in ring - porous species may be changing both diurnally and throughout the season as the large earlywood vessels cavitate and refill ( taneda and sperry , 2008 ; christman et al . , 2012 ) . therefore , one advantage of the thb system in ring - porous species is that accurate sapwood depths are not required as long as the estimated sapwood depth is covered by the sensors . as long as a sufficient sample sizes are measured , sap flow rates measured with 1-cm long td sensors should yield similar results as data measured with the thb system in q. prinus ( figure 5 ) . on the other hand , in q. velutina , the 2-cm long td sensor measured consistently higher flow rates than 1-cm long sensor , although in the range of flow rates measured by these sensors , q. prinus also showed similar values between the two sensor lengths . in a q. velutina individual , td sensors also measured lower flow rates than the thb system , with the underestimation increasing at higher flow rates . a 1-cm long td sensor in q. velutina may measure higher flow rates than a 2-cm long sensor when fluxes are greater ( 2040 kg day ) and these may match more closely with values measured by the thb system . other studies have found that heat dissipation sensors underestimate sap flow rates relative to other independent measures of flow in both ring - porous and diffuse porous angiosperm species ( montague and kjelgren , 2006 ; steppe et al . , 2010 ) . comparing sap flow rates measured with td sensors with gravimetric water loss in four angiosperm species ( pyrus calleryana decne . , quercus robur l. , populus deltoides bartram ex . marsh . , and liquidambar styraciflua l. ) , montague and kjelgren ( 2006 ) found that water loss rates were underestimated by about 45% by the td method . however , 3-cm long sensors were used , and even though a correction was applied to account for the portion of the sensor in non - conductive wood , in these small diameter trees , the portion of conducting wood may have been significantly smaller than the sensor length . likewise , in laboratory - measured stem segments of fagus grandifolia ehrh . , steppe et al . ( 2010 ) found that three methods that use heat as a tracer for sap flow , heat pulse velocity , the td method , and heat field deformation , all underestimated sap flux densities compared with gravimetric measurements , with td having the highest underestimation ( 60% ) . as has been pointed out by several other authors , not only will td sensors underestimate flow rates if a portion of the sensor is located in non - conducting wood but also if very high flow rates are concentrated along a fairly small portion of the sensor length ( clearwater et al . we found evidence for this in q. prinus with 1-cm long td sensors measuring higher flow rates than 2-cm long sensors under high flow conditions . on the other hand , the thb method is better able to deal with uneven flow rates across the sensor length ( tatarinov et al . , 2005 ) , possibly because it is designed to maintain a constant temperature in the measurement zone and adds additional energy in response to very high flow rates . this contrasts with the td system , which maintains a constant power output and its measurement ability may therefore become saturated at very high flow rates . shorter sensors distribute very localized flow rates across a larger portion of the sensor length and may be a good strategy to deal with small sapwood depths in trees ( clearwater et al . ( 2004 ) to deal with small sapwood depths involves inserting the td probes tangentially , instead of radially , into the sapwood . however , to our knowledge , this methodology has never been performed in the field . although the td system tended to underestimate flows in the quercus sp . compared to the thb system , both systems matched fairly well in the pinus sp . although we only had access to one pinus individual for comparison , sap flow rates were underestimated slightly by the td system , but only at very large flow rates . this may be a result of the radial correction factor we used , which was calculated as a step - wise decrease in flow from the outer sensor to the inner sensor . however , in reality , flow rates decrease non - linearly across the radial profile , being maximal just inside the most newly formed sapwood , then decreasing to the heartwood boundary ( ford et al . , 2004 ) . other studies have found that sap flow rates measured with the thb system and 2-cm long td sensors with a radial correction applied matched well in two conifer species , scots pine ( pinus sylvestris l. ; granier et al . , 1996 ; kstner et al . , 1996 ) and norway spruce [ p. abies ( l. ) h. karst ; kstner et al . , 1998 ] and in a tropical diffuse porous species , gliricidia sepium [ ( jacq . ) kunth ex . ( 2001 ) also compared the thb system and 2-cm long td sensors installed at 02 and 24 cm depths in scots pine and norway spruce trees and found that sap flow rates measured by the td system were up to 50% lower than the thb system at high flow rates . differences between sap flows measured with the td and thb system may be due to azimuthal variation in sap flow around the circumference of trees . although schfer et al . ( 2002 ) report no significant differences between sap flow rates measured on the north and south side of pinus taeda trees , other studies have found azimuthal differences in sap flow rates ranging from 65% ( tateishi et al . , 2008 ) to over 100% ( tsuruta et al . , 2010 ) within a given individual . in our study , the thb system tended to be located on the southern side of trees and the td system on the western and northern side of trees . however , studies have found that variability in sap flow with azimuthal position tends to be random with no predictable pattern for the cardinal direction with the most flow ( fernndez et al . ( 2008 ) measured sap flow in acacia mangium ( willd . ) in each cardinal direction ( n , s , e , w ) using td sensors and found that , in each tree , a different cardinal direction had the greatest flow rates . ( 1998 ) found that sap flow rates varied widely with azimuth in maritime pines ( pinus pinaster ait . ) when measured at breast height , but showed little azimuthal variation when measured at the base of the live crown . both the lack of azimuthal variation at the base of the live crown and the fact that no given cardinal direction has consistently the greatest sap flow rates suggests that light environment is not driving the differences in sap flow with azimuth ( tsuruta et al . , 2010 ) . however , several studies suggest that differences in hydraulic properties around the trunk largely explain the differences in sap flow rates with azimuthal location ( loustau et al . , 1998 ; these differences in hydraulic properties should be random around the circumference of the trunk and therefore would not explain why our td sensors are consistently underestimating sap flow rates relative to the thb . there is also some discussion in the literature about whether the td method should be calibrated for each individual species in which it is used ( smith and allen , 1996 ; bush et al . , 2010 ; whether granier s original calibration is universal ( lu et al . , 2004 ) . individual species calibrations may be necessary because granier s original empirical calibration is not based on physical principles ( steppe et al . , 2010 ) . it has also been suggested that new calibrations should be performed for any system based on the heat dissipation methodology that deviates from the original heating power and probe design ( lu et al . , 2004 ) . . , 2002 ) used with the original granier equation matched well with gravimetric measures of water loss . having different calibration equations for individual species detracts from the simplicity and ease of use of the td system and may limit repeatability and comparability . we found that using shorter sensor lengths in oaks with the original calibration equation resulted in differences in sap flow of about 15% when compared with the thb system . this degree of variation may be tolerable for stand level estimates of water use or other broader scale applications and is on par with the variation in other measurement methods like eddy covariance ( rana and katerji , 2000 ; wilson et al . , 2001 ; oren et al . , 2006 ) . in instances where more fine - scale sap flow measurements are necessary , individual calibrations may need to be performed . the ability to continuously measure sap flow rates in trees has led to great advances in tree physiological research and a greater understanding of ecological processes . although every sap flow monitoring system has its limitations , as long as the proper considerations are taken into account , these systems can yield valid and valuable results . likewise , through an adequate sampling either within an individual or within a plot ( depending on the goals of the research ) , underestimations and overestimations made by individual sensors can average out to an appropriate estimate of water use at the plot level . our plot level comparisons were within 15% of one another with underestimation of the td system compared to the thb system attributed to underestimation in the pinus individual ( about 9% , se = 0.03 ) as well as underestimations of flow in the quercus individuals . this research is especially important in ecosystems dominated by ring - porous species ( including oaks ) because the error associated with various methods of measuring sap flow is much different from ecosystems that are dominated by conifer or diffuse porous species . therefore , while the thb and td methods remain powerful tools to study water use in trees , their applications should periodically be reviewed in species with differing wood types to ensure that they provide the most accurate estimates of sap flow both for individual studies as well as models that use these data . the authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest .

sap flow measurements have become integral in many physiological and ecological investigations . a number of methods are used to estimate sap flow rates in trees , but probably the most popular is the thermal dissipation ( td ) method because of its affordability , relatively low power consumption , and ease of use . however , there have been questions about the use of this method in ring - porous species and whether individual species and site calibrations are needed . we made concurrent measurements of sap flow rates using td sensors and the tissue heat balance ( thb ) method in two oak species ( quercus prinus willd . and quercus velutina lam . ) and one pine ( pinus echinata mill . ) . we also made concurrent measurements of sap flow rates using both 1 and 2-cm long td sensors in both oak species . we found that both the td and thb systems tended to match well in the pine individual , but sap flow rates were underestimated by 2-cm long td sensors in five individuals of the two ring - porous oak species . underestimations of 2035% occurred in q. prinus even when a clearwater correction was applied to account for the shallowness of the sapwood depth relative to the sensor length and flow rates were underestimated by up to 50% in q. velutina . two centimeter long td sensors also underestimated flow rates compared with 1-cm long sensors in q. prinus , but only at large flow rates . when 2-cm long sensor data in q. prinus were scaled using the regression with 1-cm long data , daily flow rates matched well with the rates measured by the thb system . daily plot level transpiration estimated using td sap flow rates and scaled 1 cm sensor data averaged about 15% lower than those estimated by the thb method . therefore , these results suggest that 1-cm long sensors are appropriate in species with shallow sapwood , however more corrections may be necessary in ring - porous species .

SECTION 1. SHORT TITLE. This Act may be cited as the ``Justice in India Act''. SEC. 2. FINDINGS. The Congress finds that-- (1) each year, in both Jammu and Kashmir and the Punjab, the Government of India detains thousands of persons under special or preventive detention laws without informing them of the charges against them; (2) most of these detainees are political prisoners, including prisoners of conscience; (3) they are often detained for several months and sometimes even more than a year; (4) detainees are not permitted any contact with lawyers or family members unless they are remanded to judicial custody and transferred to prison, and only then if the family on its own is able to locate the detainee; (5) in most cases, these persons are detained under the Terrorist and Disruptive Activities (Prevention) Act of 1987, the National Security Act of 1980, and the Jammu and Kashmir Public Safety Act of 1978; (6) the Terrorist and Disruptive Activities (Prevention) Act of 1987 authorizes administrative detention without formal charge or trial for up to 1 year for investigation of suspected ``terrorist'' or broadly defined ``disruptive'' activities; (7) the 1-year period of permissible detention before trial violates Article 9 of the International Covenant on Civil and Political Rights, to which India is a party; (8) Article 9 of the International Covenant provides, ``Anyone arrested or detained on a criminal charge shall be brought promptly before a judge or other officer authorized by law to exercise judicial power and shall be entitled to trial within a reasonable time or to release.''; (9) under the Terrorist and Disruptive Activities (Prevention) Act of 1987, all proceedings before a designate court must be conducted in secret ``at any place other than...[the court's]...ordinary place of sitting''; (10) section 16(2) of the Terrorist and Disruptive Activities (Prevention) Act of 1987 permits the designated court to keep the ``identity and address of any witness secret''; (11) under the Terrorist and Disruptive Activities (Prevention) Act of 1987, a confession to a senior police officer can be admitted as evidence if there is reason to believe it was made voluntarily; (12) the Terrorist and Disruptive Activities (Prevention) Act of 1987 amends India's criminal code, which prohibits such confessions, and substantially increases the risk of torture; (13) the Terrorist and Disruptive Activities (Prevention) Act of 1987 reverses the presumption of innocence, placing the burden on the accused to prove that he or she is not guilty; (14) the National Security Act of 1980 permits the detention of persons without charge or trial for up to 1 year in order to prevent them from acting in a manner prejudicial to the security of the state, the maintenance of public order, the maintenance of supplies and services essential to the community, or relations with a foreign power; (15) the National Security Act of 1980 was amended to permit 2 years detention in the Punjab; (16) under this Act, India may detain any person engaged in behavior ``prejudicial to the defense of India, the relations of India with foreign powers, or the security of India''; (17) the Jammu and Kashmir Public Safety Act of 1978 empowers India to detain persons without trial for up to 1 year for a broad range of activities, including ``promoting, propagating, or attempting to create, feelings of enmity or hatred or disharmony on grounds of religion, race, community, or region''; (18) the Armed Forces (Punjab and Chandigarh) Special Powers Act of 1983 and the Armed Forces (Jammu and Kashmir) Special Powers Act of 1990 empower Indian security forces to search homes without warrant, to make arrests without warrant, to destroy the ``hideouts'' of suspected terrorists, and to shoot to kill with immunity from prosecution; (19) Indian security forces routinely employ methods of torture, beatings, and threats to induce detainees to sign statements of confession and to identify suspected militants; (20) the Terrorist and Disruptive Activities (Prevention) Act of 1987, the National Security Act of 1980, the Jammu and Kashmir Public Safety Act of 1978, the Armed Forces (Punjab and Chandigarh) Special Powers Act of 1983, and the Armed Forces (Jammu and Kashmir) Special Powers Act of 1990 facilitate human rights abuses by suspending ordinary safeguards against arbitrary arrest, incommunicado detention, and torture; and (21) these 5 laws are incompatible with the principles of a modern democracy. SEC. 3. REDUCTION OF DEVELOPMENT ASSISTANCE FOR INDIA UNLESS CERTAIN LAWS REPEALED. (a) Report.--Not later than 60 days after the date of the enactment of this Act, the President shall report to the Congress whether the Government of India has repealed all the laws specified in subsection (d). (b) Reduction of Assistance.--If the President reports to Congress, either pursuant to subsection (a) or at any other time, that the Government of India has not repealed all the laws specified in subsection (d), all development assistance for India under chapter 1 of part I of the Foreign Assistance Act of 1961 shall be terminated except for assistance to continue the Immunodiagnostic Development Project, the Child Survival Health Support Project, and the Private and Voluntary Organizations for Health II Project. (c) Resumption of Assistance.--Assistance terminated pursuant to subsection (b) may be resumed only if the President reports to Congress that the Government of India has repealed all the laws specified in subsection (d). (d) Special and Preventive Detention Laws.--The laws referred to in subsections (a), (b), and (c) are the Terrorist and Disruptive Activities (Prevention) Act of 1987, the National Security Act of 1980, the Jammu and Kashmir Public Safety Act of 1978, the Armed Forces (Punjab and Chandigarh) Special Powers Act of 1983, and the Armed Forces (Jammu and Kashmir) Special Powers Act of 1990.

Justice in India Act - Terminates all development assistance for India under the Foreign Assistance Act of 1961 (except assistance for specified health projects) if the President reports to the Congress that India has not repealed certain special and preventive detention laws. Provides for the resumption of such assistance if India repeals such laws.

The video will start in 8 Cancel Get daily updates directly to your inbox + Subscribe Thank you for subscribing! Could not subscribe, try again later Invalid Email A panicked woman was rushed to hospital after eating a poisonous plant she thought was a harmless aloe vera leaf on an internet live stream. The 26-year-old Chinese woman, surnamed Zhang, broadcast her unusual food fetish to several hundred viewers and even bought two massive green leaves for the performance. She claimed the leaves were aloe verab - and that there was no better way to reap the plant's benefits than by chowing down on the thick, fresh leaves. But her "Aloe Vera Feast" - as her channel's stream was title - turned very bad, very fast as she actually ate the leaves of a century plant - which is also called the agave Americana. (Image: Asiawire) The poison desert plant from the Americas, which resembles aloe vera, is sold in China as an ornament, and its likeness to aloe vera is thought to have fooled the woman. In footage of the live broadcast, Zhang can be heard saying: "This is great. Yum." But viewers sensed something was wrong when she added: "Oh, that's bitter. That is really bitter." (Image: Asiawire) Zhang, who is still recovering in hospital, later claimed her mouth went "numb" and she felt like her throat was "on fire". She also "lost her voice" after three bites of the agave Americana and immediately took herself to hospital, abandoning the live stream entirely. Doctors found that she had also been suffering from severe rashes and blisters, and later pumped her stomach to remove the harmful substances from her body. ||||| One woman has managed to win internet fame, though not exactly in the way that she had hoped after being forced to abruptly end her live stream and rush herself to the hospital after discovering that the plant she was eating was not what she thought it was. To prepare for her live stream, the 26-year-old woman surnamed Zhang had bought two waxy green leaves that she thought were aloe vera, a plant purported to have various health benefits when eaten raw. After taking her first bite, Zhang exclaims, "This is great!" However, upon taking her second bite, she begins to realize that something is terribly wrong. "Oh, that tastes bitter. Really bitter," she says to the camera. It turns out that what Zhang was chomping down on was not aloe vera, but Agave Americana (American aloe), a poisonous plant from Mexico that is very not edible. Zhang said that just one bite made her mouth go numb and her throat feel like it was on fire. At the hospital, doctors found that Zhang had broken out into rashes and blisters and were forced to pump her stomach to remove parts of the poisonous plant and save her life. She is reported to be in stable condition. [Images via Oriental Daily / h/t Asia One]

– A Chinese woman was live-streaming herself eating what she thought was aloe vera (said to have health benefits when eaten raw) when she abruptly realized something was very wrong. It turns out the 26-year-old, named in the media only as Zhang, was actually eating Agave Americana or "American aloe," a poisonous plant from Mexico, Shanghaiist reports. Though video of the woman shows her initially proclaiming the first bite as "great," Zhang quickly changed her tune, proclaiming the plant "really bitter." She later said her mouth went numb and her throat started burning, the Mirror reports. She ended up rushing herself to the hospital, having broken out in rashes and blisters, and doctors reportedly had to pump her stomach to save her life.

SECTION 1. SHORT TITLE. This Act may be cited as the ``Northern Ireland Fair Employment Practices Act of 1995''. SEC. 2. FINDINGS. The Congress finds the following: (1) Currently, overall unemployment in Northern Ireland is approximately 13 percent, as compared to 9 percent in the rest of the United Kingdom. (2) Unemployment in the minority community in Northern Ireland is 22.8 percent, and in some portions of the minority community unemployment has historically exceeded 70 percent. (3) The British Government Fair Employment Commission (F.E.C.), formerly the Fair Employment Agency (F.E.A.), has consistently reported that a member of the minority community is two times more likely to be unemployed than a member of the majority community. (4) The Investor Responsibility Research Center (IRRC), Washington, District of Columbia, lists 80 publicly held United States companies doing business in Northern Ireland, which employ approximately 11,000 individuals. (5) The religious minority population of Northern Ireland is subject to discriminatory hiring practices by some United States businesses which have resulted in a disproportionate number of minority individuals holding menial and low-paying jobs. (6) The MacBride Principles are a nine point set of guidelines for fair employment in Northern Ireland which establishes a corporate code of conduct to promote equal access to regional employment but does not require disinvestment, quotas, or reverse discrimination. SEC. 3. RESTRICTION ON IMPORTS. An article from Northern Ireland may not be entered, or withdrawn from warehouse for consumption, in the customs territory of the United States unless there is presented at the time of entry to the customs officer concerned documentation indicating that the enterprise which manufactured or assembled such article was in compliance at the time of manufacture with the principles described in section 5. SEC. 4. COMPLIANCE WITH FAIR EMPLOYMENT PRINCIPLES. (a) Compliance.--Any United States person who-- (1) has a branch or office in Northern Ireland, or (2) controls a corporation, partnership, or other enterprise in Northern Ireland, in which more than twenty people are employed shall take the necessary steps to ensure that, in operating such branch, office, corporation, partnership, or enterprise, those principles relating to employment practices set forth in section 5 are implemented and this Act is complied with. (b) Report.--Each United States person referred to in subsection (a) shall submit to the Secretary-- (1) a detailed and fully documented annual report, signed under oath, on showing compliance with the provisions of this Act; and (2) such other information as the Secretary determines is necessary. SEC. 5. MACBRIDE PRINCIPLES. The principles referred to in section 4 are the MacBride Principles, which are as follows: (1) Increasing the representation of individuals from underrepresented religious groups in the work force including managerial, supervisory, administrative, clerical, and technical jobs.--A workforce that is severely unbalanced may indicate prima facie that full equality of opportunity is not being afforded all segments of the community in Northern Ireland. Each signatory to the MacBride Principles must make every reasonable lawful effort to increase the representation of underrepresented religious groups at all levels of its operations in Northern Ireland. (2) Adequate security for the protection of minority employees both at the workplace and while travelling to and from work.--While total security can be guaranteed nowhere today in Northern Ireland, each signatory to the MacBride Principles must make reasonable good faith efforts to protect workers against intimidation and physical abuse at the workplace. Signatories must also make reasonable good faith efforts to ensure that applicants are not deterred from seeking employment because of fear for their personal safety at the workplace or while travelling to and from work. (3) The banning of provocative religious or political emblems from the workplace.--Each signatory to the MacBride Principles must make reasonable good faith efforts to prevent the display of provocative sectarian emblems at their plants in Northern Ireland. (4) All job openings should be advertised publicly and special recruitment efforts made to attract applicants from underrepresented religious groups.--Signatories to the MacBride Principles must exert special efforts to attract employment applications from the sectarian community that is substantially underrepresented in the workforce. This should not be construed to imply a diminution of opportunity for other applicants. (5) Layoff, recall, and termination procedures should not in practice favor a particular religious group.--Each signatory to the MacBride Principles must make reasonable good faith efforts to ensure that layoff, recall, and termination procedures do not penalize a particular religious group disproportionately. Layoff and termination practices that involve seniority solely can result in discrimination against a particular religious group if the bulk of employees with greatest seniority are disproportionately from another religious group. (6) The abolition of job reservations, apprenticeship restrictions, and differential employment criteria which discriminate on the basis of religion.--Signatories to the MacBride Principles must make reasonable good faith efforts to abolish all differential employment criteria whose effect is discrimination on the basis of religion. For example, job reservations, and apprenticeship regulations that favor relatives of current or former employees can, in practice, promote religious discrimination if the company's workforce has historically been disproportionately drawn from another religious group. (7) The development of training programs that will prepare substantial numbers of current minority employees for skilled jobs, including the expansion of existing programs and the creation of new programs to train, upgrade, and improve the skills of minority employees.--This does not imply that such programs should not be open to all members of the workforce equally. (8) The establishment of procedures to assess, identify, and actively recruit minority employees with potential for further advancement.--This section does not imply that such procedures should not apply to all employees equally. (9) The appointment of a senior management staff member to oversee the company's affirmative action efforts and the setting up of timetables to carry out affirmative action principles.--In addition to the above, each signatory to the MacBride Principles is required to report annually to an independent monitoring agency on its progress in the implementation of these Principles. SEC. 6. WAIVER OF PROVISIONS. (a) Waiver of Provisions.--In any case in which the President determines that compliance by a United States person with the provisions of this Act would harm the national security of the United States, the President may waive those provisions with respect to that United States person. The President shall publish in the Federal Register each waiver granted under this section and shall submit to the Congress a justification for granting each such waiver. Any such waiver shall become effective at the end of ninety days after the date on which the justification is submitted to the Congress unless the Congress, within that ninety-day period, adopts a joint resolution disapproving the waiver. In the computation of such ninety-day period, there shall be excluded the days on which either House of Congress is not in session because of an adjournment of more than three days to a day certain or because of an adjournment of the Congress sine die. (b) Consideration of Resolutions.-- (1) Any resolution described in subsection (a) shall be considered in the Senate in accordance with the provisions of section 601(b) of the International Security Assistance and Arms Export Control Act of 1976. (2) For the purpose of expediting the consideration and adoption of a resolution under subsection (a) in the House of Representatives, a motion to proceed to the consideration of such resolution after it has been reported by the appropriate committee shall be treated as highly privileged in the House of Representatives. SEC. 7. DEFINITIONS AND PRESUMPTIONS. (a) Definitions.--For the purpose of this Act-- (1) the term ``United States person'' means any United States resident or national and any domestic concern (including any permanent domestic establishment of any foreign concern); (2) the term ``Secretary'' means the Secretary of Commerce; and (3) the term ``Northern Ireland'' includes the counties of Antrim, Armagh, Londonderry, Down, Tyrone, and Fermanagh. (b) Presumption.--A United States person shall be presumed to control a corporation, partnership, or other enterprise in Northern Ireland if-- (1) the United States person beneficially owns or controls (whether directly or indirectly) more than 50 percent of the outstanding voting securities of the corporation, partnership, or enterprise; (2) the United States person beneficially owns or controls (whether directly or indirectly) 25 percent or more of the voting securities of the corporation, partnership, or enterprise, if no other person owns or controls (whether directly or indirectly) an equal or larger percentage; (3) the corporation, partnership, or enterprise is operated by the United States person pursuant to the provisions of an exclusive management contract; (4) a majority of the members of the board of directors of the corporation, partnership, or enterprise are also members of the comparable governing body of the United States person; (5) the United States person has authority to appoint the majority of the members of the board of directors of the corporation, partnership, or enterprise; or (6) the United States person has authority to appoint the chief operating officer of the corporation, partnership, or enterprise. SEC. 8. EFFECTIVE DATE. This Act shall take effect 180 days after the date of enactment of this Act.

Northern Ireland Fair Employment Practices Act of 1995 - Prohibits an article from being imported into the United States from Northern Ireland unless documentation is presented at the time of entry indicating that the enterprise which manufactured or assembled such article complied at the time of manufacture with certain fair employment principles (such as freedom from religious discrimination). Bases such principles on the MacBride Principles, a nine-point set of guidelines for fair employment in Northern Ireland. Requires any U.S. person who has a branch or office in Northern Ireland or who controls an enterprise in Northern Ireland in which more than 20 people are employed to insure implementation of such employment principles and compliance with this Act. Authorizes the President to waive the requirements of this Act in the interest of national security.

Buffett challenges Trump to release tax returns The Omaha billionaire also compared Trump to Joseph McCarthy in a speech promoting Hillary Clinton. Warren Buffett on Monday directly challenged Donald Trump to release his tax returns during a campaign stop with Hillary Clinton in his hometown of Omaha, Nebraska. “He said 'none of your business,' which did not go over so well, and then he started giving various explanations. And one of the explanations was that he had given his financial statement to the election commission and listed his assets and liabilities,” the Berkshire Hathaway chairman recounted at a local high school as Clinton sat on stage next to him. Story Continued Below Trump has claimed that the returns in any case would hold little news value. “But believe me," Buffett countered, "as someone who’s filled out financial statements and someone who has filled out an income tax return, I call tell you, they are two very different animals. You will learn a whole lot more about Donald Trump if he produces his income tax return.” Buffett then remarked that he would “like to make [Trump] an offer, an offer I hope he can’t refuse.” Noting that Trump often cites the fact that his taxes are under audit, Buffett mused, “I've got news for him, I'm under audit too. I would be delighted to meet him any time, any place before the election.” “I'll bring my tax return. He can bring his tax return. Nobody is going to arrest us. There are no rules against showing your tax returns and just let[ting] people ask questions about the items that are on there,” Buffett said, before asking the boisterous crowd, “How many of you would be afraid to have your tax return made public?” “You're only afraid if you got something to be afraid about. He's not afraid of the IRS. He's afraid because of you. I will meet him in Omaha or Mar-a-Lago or he can pick the place,” Buffett offered. “We're both under audit. And believe me, nobody will stop us from talking about what's on those returns. Send the word to him, if you will.” Buffett also took issue with Trump saying the U.S. is no longer great, ripping into the Republican nominee for his attacks on the family of a fallen Army captain after his father, Khizr Khan, gave a speech at the Democratic convention denouncing anti-Muslim rhetoric and accusing Trump of never making sacrifices for his country. Referring specifically to Trump’s claim to ABC’s George Stephanopoulos that he, too, has made sacrifices, Buffett invoked the McCarthy hearings. “No member of the Buffett family has gone to Iraq or Afghanistan. No member of the Trump family has gone to Iraq or Afghanistan,” Buffett said. “We have both done extremely well during this period and our families haven't sacrificed anything, and Donald Trump and I haven't sacrificed anything, but how in the world can you stand up to a couple of parents who have lost a son and talk about sacrificing because you were building a bunch of buildings?” “When I heard that, my mind went back -- and this goes back before most of you were born -- but they went back to the McCarthy hearings. And at the time of the McCarthy hearings, at the time of the McCarthy hearings with the Army, Joe Welch had a young assistant of his maligned by Sen. [Joseph] McCarthy, and McCarthy went on and on, implying this guy was a communist and doing all kinds of things. And finally, Joe Welch couldn't take it anymore and he said and I'll quote him, 'Have you no sense of decency, sir?' I ask Donald Trump: 'Have you no sense of decency, sir?'” Buffett said to cheers and applause. “I might add, just add one thing: McCarthy’s career went straight downhill after that. It did.” Authors: ||||| Speaking at a rally of Democratic presidential nominee Hillary Clinton in Omaha, Aug. 1, billionaire Warren Buffett offered Donald Trump that both men release their tax returns together and answer questions from the public. (The Washington Post) OMAHA — Two wealthy men, two IRS audits, two tax returns, and one date — possibly. Warren Buffett threw down the gauntlet Monday in Omaha, challenging Donald Trump to release his tax returns “anytime, anywhere” between now and election day. Buffett, chief executive of Berkshire Hathaway and among the top 10 richest men in the world, called it “an offer I hope he can’t refuse.” “I’ll bring my return, he’ll bring his return, we’re both under audit,” Buffett said. “You will learn a whole lot more about Donald Trump if he produces his income tax returns." At a rally in Omaha, on Aug. 1, Democratic presidential nominee Hillary Clinton pledged to dance with billionaire Warren Buffett if Nebraska's 2nd Congressional District has the highest voter turnout nationwide. (The Washington Post) He noted that Trump has released a financial statement in lieu of his tax returns, but Buffett said that it isn’t enough. “As someone who’s filled out financial statements and someone who’s filled out an income tax return, I can tell ya, they are two very different animals,” Buffett said. “He’s not afraid because of the IRS, he’s afraid because of you,” he added. “You’re only afraid if you’ve got something to be afraid about.” Buffett spoke at a rally here, where he introduced Hillary Clinton and sharply criticized Trump. In addition to a new challenge for Trump to release his tax returns, Buffett criticized him for suggesting that "building a bunch of buildings" is a sacrifice like the one made by the families of fallen soldiers. He was referring to Trump's criticism of the Muslim American parents of an Army officer killed in Iraq in 2004. Billionaire Warren Buffett was the latest to respond to Republican presidential candidate Donald Trump's attacks on the Ghazala and Khizr Khan while campaigning for Democratic candidate Hillary Clinton in Omaha on Aug. 1 (Gillian Brockell/The Washington Post) "No member of the Buffett family has gone to Iraq or Afghanistan. No member of the Trump family has gone to Iraq or Afghanistan," Buffett said. "Donald Trump and I have sacrificed nothing. "I ask Donald Trump: Have you no sense of decency, sir?" Clinton's fairly unusual campaign stop in Omaha is targeting a small, but potentially important single electoral vote that is up for grabs because of a quirk in election law. Nebraska's 2nd Congressional District, which encompasses the more liberal enclave of Omaha, can award a single electoral college vote differently from the rest of the state. Buffett challenged the crowd to turn out to vote on Election Day, and he even put some skin in the game, promising to personally take people to the polls. "I reserved a trolley for November 8th. At 6:32, I'm going to be on it all day, I'm going to do selfies — whatever it takes," Buffett said. "My goal is to have the turnout here be the highest percentage of potential voters of any district in the country." Clinton upped the ante, promising that if turnout is high on election day, she would return to Nebraska as president. "I will — shortly after I become president, sometime as soon as I can arrange it — come back here and Warren and I will dance in the streets of Omaha together," Clinton said. Plus, she added, Buffett will wear his Elvis costume.

– Warren Buffett has challenged Donald Trump over the candidate's refusal to release his tax returns, saying he will meet him "anytime, anyplace" and bring his own income tax return along. The Berkshire Hathaway CEO—whose fortune dwarfs that of Trump—told a Hillary Clinton rally in Omaha, Neb., Monday night that he isn't buying Trump's excuse that he's under audit, because Buffett is also under audit and is free to talk about his taxes, Politico reports. "You're only afraid if you got something to be afraid about. He's not afraid of the IRS. He's afraid because of you," Buffett told the crowd. "I will meet him in Omaha or Mar-a-Lago or he can pick the place," he said. "We're both under audit. And believe me, nobody will stop us from talking about what's on those returns. Send the word to him, if you will." "You will learn a whole lot more about Donald Trump if he produces his income tax return," Buffett promised. He also brought up Trump's feud with Khizr Khan, looking back to the McCarthy hearings, when Sen. Joseph McCarthy persistently implied that an assistant to Army chief counsel Joe Welch was a Communist. "Joe Welch couldn't take it anymore and he said, and I'll quote him, 'Have you no sense of decency, sir?'" Buffet said. "I ask Donald Trump: Have you no sense of decency, sir?" Nebraska hasn't gone Democratic since 1964, but the Washington Post notes that a quirk in how delegates are awarded means Clinton has a chance at winning an electoral vote from the state's 2nd Congressional District. Buffett promised to bring people to the polls himself and said his goal is for the district to have the highest turnout in the country.

the absolute value of neutrino masses are very difficult to measure experimentally . on the other hand , mass differences between neutrino mass eigenstates , @xmath0 , can be measured in neutrino oscillation experiments . observations of atmospheric neutrinos suggest a squared mass difference of @xmath1 ev@xmath2 @xcite . while there are still several viable solutions to the solar neutrino problem the so - called large mixing angle solution gives by far the best fit with @xmath3 ev@xmath2 @xcite ( see also contributions by a. hallin and a. smirnov in the present volume ) . in the simplest case where neutrino masses are hierarchical these results suggest that @xmath4 , @xmath5 , and @xmath6 . if the hierarchy is inverted @xcite one instead finds @xmath7 , @xmath8 , and @xmath9 . however , it is also possible that neutrino masses are degenerate @xcite , @xmath10 , in which case oscillation experiments are not useful for determining the absolute mass scale . experiments which rely on kinematical effects of the neutrino mass offer the strongest probe of this overall mass scale . tritium decay measurements have been able to put an upper limit on the electron neutrino mass of 2.2 ev ( 95% conf . ) @xcite ( see also the contribution by ch . weinheimer in the present volume ) . however , cosmology at present yields an even stronger limit which is also based on the kinematics of neutrino mass . neutrinos decouple at a temperature of 1 - 2 mev in the early universe , shortly before electron - positron annihilation . therefore their temperature is lower than the photon temperature by a factor @xmath11 . this again means that the total neutrino number density is related to the photon number density by @xmath12 massive neutrinos with masses @xmath13 ev are non - relativistic at present and therefore contribute to the cosmological matter density @xcite @xmath14 calculated for a present day photon temperature @xmath15k . here , @xmath16 . however , because they are so light these neutrinos free stream on a scale of roughly @xmath17 @xcite . below this scale neutrino perturbations are completely erased and therefore the matter power spectrum is suppressed , roughly by @xmath18 @xcite . this power spectrum suppression allows for a determination of the neutrino mass from measurements of the matter power spectrum on large scales . this matter spectrum is related to the galaxy correlation spectrum measured in large scale structure ( lss ) surveys via the bias parameter , @xmath19 . such analyses have been performed several times before @xcite , most recently using data from the 2df galaxy survey @xcite . this investigation finds an upper limit of 1.8 - 2.2 ev for the sum of neutrino masses . however , this result is based on a relatively limited cosmological parameter space . for the same data and an even more restricted parameter space an upper limit of 1.5 ev was found @xcite . it should also be noted that , although massive neutrinos have little impact on the cosmic microwave background ( cmb ) power spectrum , it is still necessary to include cmb data in any analysis in order to determine other cosmological parameters . when calculating bounds on the neutrino mass from cosmological observations great care must be taken , because if the analysis is based on a too restricted parameter space , possible parameter degeneracies can not be studied and the bound on @xmath20 can become artificially strong . in fig . 1 the degeneracy between different cosmological parameters is shown in form of the quantity @xmath21 i.e. the decrease in uncertainty of a measurement of parameter @xmath22 when parameter @xmath23 is fixed . from this figure it can be seen that there are significant degeneracies between @xmath24 and other parameters , most notably @xmath25 , the bias parameter , and @xmath26 , the matter density . in ref . @xcite a full numerical likelihood analysis was performed using a slightly restricted parameter space with the following free parameters : @xmath26 , @xmath27 , @xmath28 , @xmath29 , @xmath30 , @xmath25 , and @xmath31 . the analysis was further restricted to flat models , @xmath32 . this has very little effect on the analysis because there is little degeneracy between @xmath20 and @xmath33 . in order to study the effect of the different priors three different cases were calculated , the priors for which can be seen in table i. the bbn prior on @xmath34 comes from ref . the actual marginalization over parameters other than @xmath35 was performed using a simulated annealing procedure @xcite . 2 shows @xmath36 for the three different cases as a function of the @xmath20 . the best fit @xmath36 values are 24.81 , 25.66 , and 25.71 for the three different priors respectively . in comparison the number of degrees of freedom are 34 , 35 , and 36 , meaning that the fits are compatible with expectations , roughly within the 68% confidence interval . the 95% confidence limit on @xmath20 was identified with the point where @xmath37 . these limits are shown in table ii . for the most restrictive prior we find a 95% confidence upper limit of @xmath38 ev . this is compatible with the findings of ref . @xcite who derived that @xmath39 ev for a slightly more restrictive parameter space . based on the present analysis we consider @xmath40 ev ( 95% conf . ) a robust upper limit on the sum of the neutrino masses . this corresponds roughly to the value found for the cmb+lss data alone without any additional priors . even though this value is significantly higher than what is quoted in ref . @xcite , it is still much more restrictive than the value @xmath41 ev @xcite found from cmb and pscz @xcite data . as is also discussed in ref . @xcite the main reason for the improvement is the much greater precision of the 2df survey , compared to the pscz data @xcite . in the near future a much more accurate determination of @xmath42 from cmb measurements will become possible thanks to the satellites map and planck . it was estimated by lopez et al . @xcite that it would be possible to measure @xmath43 using planck data . however , this is probably overly optimistic and a more reasonable estimate seems to be @xmath44 @xcite . v. a. kostelecky and s. samuel , phys . b * 318 * , 127 ( 1993 ) . g. m. fuller , j. r. primack and y. z. qian , phys . d * 52 * , 1288 ( 1995 ) [ arxiv : astro - 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we review the current status of neutrino cosmology , focusing mainly on the question of the absolute values of neutrino masses and the possibility of a cosmological neutrino lepton asymmetry .

09:04 The 12 players and coach of the Wild Boars football team dramatically rescued from a Thai cave last week have spoken publicly about their ordeal for the first time at a press conference beamed around the world. A packed crowd greeted the youngsters after they were discharged from hospital in Chiang Rai, and watched as they played with footballs on a small makeshift pitch before taking their seats. “It is a miracle,” Wild Boars footballer Adul Sam-on, 14, said of the rescue, as the boys were gently quizzed about their terrifying experience. That’s it for now. Here’s a full write-up: ||||| Chiang Rai, Thailand (CNN) Members of the "Wild Boars" Thai youth soccer team and their coach have described their rescue from a flooded cave as a miracle, thanked the experts who saved them and discussed how the experience will affect the rest of their lives. In their first public remarks since emerging from their two-week ordeal last week, the boys recounted their side of an extraordinary story that captured the imagination of the world. Dressed in matching Wild Boars team shirts, the boys and their coach appeared happy and relaxed as they faced the world's media after being discharged from Chiang Rai Prachanukroh hospital on Wednesday. Adun Sam-On, a 14-year-old who became famous after responding in English to the first British diver to reach the group, spoke of his shock on realizing they had been discovered. All he could think to say was, "Hello!" "I thought this was really a miracle. I didn't know how to respond," Adun said. The youngest, 11-year-old Chanin "Titan" Wibrunrungrueang, described the hunger the boys experienced in the days before they were found. "I tried not to think about food because it would make me hungry," Titan said. Members of the Wild Boars soccer team at the press conference. The press conference was carefully arranged in order to minimize any trauma for the boys. Medical staff sat among them, and questions were pre-screened. Over the course of 90 minutes, the boys told of the moment they realized they were trapped, how they adapted to their surroundings and their eventual joy at being found, ten days later. Why go in? Until Wednesday, the question of why the boys and their coach had decided to go into the Tham Luang cave on June 23 has been a point of speculation. It had been suggested the boys had been engaged in an initiation rite, or had been celebrating a team-member's birthday. In fact, 25-year-old coach Ekapol Chantawong explained, the boys were merely curious to look inside as some of them had never visited it before. The coach, whose nickname is Ake, said it was not unusual for the group to participate in group activities after soccer practice on Saturday afternoons. They explored the underground tunnels for about an hour, before deciding to turn back. But by this time the cave had become partially flooded and their exit was blocked. "Someone said are we lost?" said Ake. At his point, the realization dawned that they were trapped. With the entrance flooded and no obvious way out, the group retreated further into the cave to find somewhere to to rest for the night. "We moved further in for about 200 meters," Ake said. "There we found a bit of slope and there was a small water source inside the cave." Ake knew that the water dripping from the roof of the cave would be purer than the dirty floodwater on the floor. "I told them it's better to be near a water source," Ake said. "Before we slept, I told them, 'Let's say a prayer.' So we said a prayer that night." The team were not scared, Ake told the enraptured audience, explaining that he hoped the water level would drop the next day, and that help would arrive. Waters rising The waters did not subside, however. Instead, Ake described the moment, some days later, that he heard the sound of flowing water -- and saw the levels rising fast. In response, he ordered the group to find higher ground. Concerned that they might soon be submerged, he instructed the boys to start digging and look for a potential exit. Having eaten after soccer practice, the boys had no food during their ordeal. Instead, they filled themselves with water from the cave. "Mostly we drank water dripping from the rock, from higher up," said 16-year-old Pornchai "Tee" Kamluang. "It tasted like normal drinking water but no food." Titan, the 11-year-old, pined for his favorite dishes. "I was thinking about fried rice. Or some chill dip." The boys tried to keep each other's spirits up. "I told them, 'don't lose hope,'" one team member said. "I was scared that I couldn't go home and my mum would complain a lot," another added, to laughter. As the days wore on, the weaker the boys became. "I tried to fill my stomach with water," Titan said. Coach Ekkapol Chantawong, left, pays tribute to Saman Kunan, the Thai Navy SEAL who died during the resuce attempt. The moment they were found Adun, the 14-year-old, described the moment, ten days into their ordeal, when two British cave divers, John Volanthen and Richard Stanton, emerged from the waters below their perch. Adun, like other members of the group, was busy digging -- looking for a possible way out -- when some of the boys thought they heard the sound of people talking. Coach Ake told the group to stay quiet. He asked one of the boys to move closer to the ledge and shine a flashlight on the water, but the boy, Panumas "Mig" Sangdee, 13, was too scared, said Adun, who volunteered instead. Adun said he was shocked to hear the divers speak in English -- at first he expected the rescuers to be Thai. The Wild Boars were smiling and relaxed when they arrived at the press conference. The boys described how they formed a bond with the Thai Navy SEALs who remained with them in the cave while rescuers worked out a plan to free them. Titan described how they played checkers -- and that one of the Navy SEALs sitting alongside them at the press conference always won. "He was king of the cave," Titan said. When the decision was made to extract the boys through the floodwaters, coach Ake joked he and the boys made the decision on who should go first based on who lived the furthest away. Ake thought the rescued kids would go straight home and those who got out first could spread the word, not realizing the global media had descended on the cave. Relatives of Duangpetch Promthep, one of the rescued boys, watch the press conference live on television. Lessons learned When asked about the lessons they've learned from the incident, Ake said he was going to live life more carefully. Ardun said though people can't predict the future, the experience had taught him about the consequences of acting carelessly. Other boys said though they still dreamed of becoming soccer players, some said they now wanted to become Navy SEALs. Many of the boys apologized to their parents for not telling them they went to the cave. Now that the boys' ordeal is over, there are concerns over their long-term psychological health. "We don't know what wounds the kids are carrying in their hearts," said Tawatchai Thaikaew, an official at the Thai justice ministry. He urged the media to respect the boys' privacy in the future, out of concern for their health, Reuters said. Some of the boys are stateless, and the process of granting them Thai citizenship is under way, officials confirmed. The largely joyous mood of the press conference was tempered, however, when the boys and their coach discussed the loss of Saman Kunan, the former Thai Navy SEAL who had died during the rescue effort. Coach Ake said the team were shocked to learn of Saman Kunan's death, called him a hero and said he had sacrificed his life for theirs. In memory of the navy diver, Ake said the boys would spend time as novice Buddhist monks -- a practice considered a high honor in Thailand. ||||| First video messages from rescued Thai boys As well as updating people on their health and sending thanks, the boys had something else on their mind.

– Before help finally arrived, the 12 boys and soccer coach trapped in a flooded cave system in Thailand tried to dig their way out. Speaking publicly for the first time at a press conference in Chiang Rai shortly after leaving a hospital Wednesday, the team described moving backward through the cave, hoping to find a way out. Eventually, they took turns digging for something to do. All the while, "we heard the water rising towards us," the Guardian quotes coach Ekaphol Chantawong as saying. "We didn't realize how far the water could rise." Indeed, Chantawong said all members of the team—who appeared happy and smiling—agreed to explore the cave for the first time on June 23 but found their return path had been partially flooded after only an hour, per CNN. Though the boys could swim, it wasn't enough to escape, Chantawong added. One boy said he thought of his mother, another said he worried about homework. All expressed their thanks and apologized for not telling their parents of their plan. Now in good health and able to return home, the boys—including four who are to receive Thai citizenship—dream of becoming professional soccer players or Navy SEALs. They also plan to join the Thai monkhood as novices, as Chantawong previously did, in honor of the diver who died during the rescue operation, per the Guardian. "It's for their protection," a grandfather of one of the boys tells the BBC. "It's like they died, but now have been reborn." Per the BBC, some locals feel the boys need to be spiritually cleansed based on the belief that their venture offended the spirit of a mythical princess said to have occupied the Tham Luang cave for centuries.

we would like to thank ushnish ray , daniel freeman , bill huggins , miles stoudenmire , birgitta whaley and brian swingle for useful discussions . this work was supported through the scientific discovery through advanced computing ( scidac ) program funded by the u.s . department of energy , office of science , advanced scientific computing research and basic energy sciences . we used the extreme science and engineering discovery environment ( xsede ) , which is supported by the national science foundation grant no . oci-1053575 and resources of the oak ridge leadership computing facility ( olcf ) at the oak ridge national laboratory , which is supported by the office of science of the u.s . department of energy under contract no . de - ac0500or22725 . 87ifxundefined [ 1 ] ifx#1 ifnum [ 1 ] # 1firstoftwo secondoftwo ifx [ 1 ] # 1firstoftwo secondoftwo `` `` # 1''''@noop [ 0]secondoftwosanitize@url [ 0 ] + 12$12 & 12#1212_12%12@startlink[1]@endlink[0]@bib@innerbibempty link:\doibase 10.1038/nature08482 [ * * , ( ) ] http://dx.doi.org/10.1038/nature09378 [ * * , ( ) ] @noop ( ) , http://stacks.iop.org/0034-4885/79/i=5/a=054401 [ * * , ( ) ] link:\doibase 10.1103/physrevlett.114.193001 [ * * , ( ) ] link:\doibase 10.1103/physrevlett.115.263001 [ * * , ( ) ] link:\doibase 10.1103/physreva.91.041602 [ * * , ( ) ] link:\doibase 10.1103/physrevlett.105.265303 [ * * , ( ) ] @noop * * , ( ) http://dx.doi.org/10.1038/nature10120 [ * * , ( ) ] link:\doibase 10.1103/physrevlett.113.260501 [ * * , ( ) ] link:\doibase 10.1103/physrevlett.111.020401 [ * * , ( ) ] http://dx.doi.org/10.1038/ncomms1147 [ * * , ( ) ] link:\doibase 10.1103/physrevb.90.081116 [ * * , ( ) ] @noop ( ) , link:\doibase 10.1103/physrevb.87.081108 [ * * , ( ) ] \doibase http://dx.doi.org/10.1063/1.2437215 [ * * , ( ) , http://dx.doi.org/10.1063/1.2437215 ] @noop ( ) , @noop ( ) , @noop ( ) , link:\doibase 10.1103/physrevlett.104.193001 [ * * , ( ) ] link:\doibase 10.1103/revmodphys.73.33 [ * * , ( ) ] http://scitation.aip.org/content/aip/journal/jcp/135/24/10.1063/1.3665391 [ * * , ( ) ] \doibase http://dx.doi.org/10.1063/1.4931667 [ * * , ( ) ] link:\doibase 10.1103/physrev.138.a442 [ * * , ( ) ] link:\doibase 10.1103/physrevb.77.115112 [ * * , ( ) ] \doibase http://dx.doi.org/10.1063/1.4829835 [ * * , ( ) ] http://scitation.aip.org/content/aip/journal/jcp/124/22/10.1063/1.2204600 [ * * , ( ) ] link:\doibase 10.1103/revmodphys.85.693 [ * * , ( ) ] link:\doibase 10.1016/j.aop.2010.09.012 [ * * , ( ) ] link:\doibase 10.1103/physrevlett.71.2777 [ * * , ( ) ] link:\doibase 10.1103/physreve.55.6202 [ * * , ( ) ] link:\doibase 10.1103/physrevb.93.035125 [ * * , ( ) ] link:\doibase 10.1103/physrevlett.107.087204 [ * * , ( ) ] http://scitation.aip.org/content/aip/journal/jcp/135/18/10.1063/1.3659143 [ * * , ( ) ] link:\doibase 10.1103/physreva.90.042507 [ * * , ( ) ] `` , '' in @noop _ _ ( , ) chap . , pp . link:\doibase 10.1103/physrevlett.115.045301 [ * * , ( ) ] @noop ( ) , @noop ( ) , link:\doibase 10.1103/physrevb.87.235112 [ * * , ( ) ] @noop * * , ( ) @noop link:\doibase 10.1146/annurev - conmatphys-020911 - 125018 [ * * , ( ) ] , @noop * * , ( ) link:\doibase 10.1103/physrevb.83.153101 [ * * , ( ) ] \doibase http://dx.doi.org/10.1016/j.commatsci.2015.11.047 [ * * , ( ) ] @noop _ _ ( , ) link:\doibase 10.1142/s0217984909017777 [ * * , ( ) ] http://dx.doi.org/10.1038/nphys3695 [ * * , ( ) ] link:\doibase 10.1103/physreva.91.023625 [ * * , ( ) ] link:\doibase 10.1103/physreva.87.051603 [ * * , ( ) ] @noop _ _ ( , ) link:\doibase 10.1103/physrevlett.45.566 [ * * , ( ) ] link:\doibase 10.1103/revmodphys.80.517 [ * * , ( ) ] link:\doibase 10.1103/revmodphys.77.259 [ * * , ( ) ] link:\doibase 10.3390/e18070240 [ * * , ( ) ] link:\doibase 10.1103/physrevlett.114.206402 [ * * , ( ) ] link:\doibase 10.1103/physrevlett.96.100503 [ * * , ( ) ] link:\doibase 10.1103/physrevlett.96.010404 [ * * , ( ) ] link:\doibase 10.1103/physrevlett.96.110405 [ * * , ( ) ] link:\doibase 10.1103/physrevb.92.035154 [ * * , ( ) ] link:\doibase 10.1103/physrevlett.96.110404 [ * * , ( ) ] link:\doibase 10.1103/physrevlett.107.067202 [ * * , ( ) ] http://dx.doi.org/10.1038/nphys2465 [ * * , ( ) ] http://dx.doi.org/10.1038/nphys3803 [ * * , ( ) ] link:\doibase 10.1103/physrevb.90.134302 [ * * , ( ) ] link:\doibase 10.1103/physrevlett.101.010504 [ * * , ( ) ] link:\doibase 10.1103/physreva.74.032306 [ * * , ( ) ] link:\doibase 10.1103/physrevlett.109.020504 [ * * , ( ) ] link:\doibase 10.1103/physrevlett.109.020505 [ * * , ( ) ] @noop ( ) , http://dx.doi.org/10.1038/nature15750 [ * * , ( ) ] @noop * * , ( ) @noop ( ) , link:\doibase 10.1103/physrevb.94.064524 [ * * , ( ) ] link:\doibase 10.1103/physrevb.93.125107 [ * * , ( ) ] link:\doibase 10.1103/physrevlett.117.010603 [ * * , ( ) ] link:\doibase 10.1103/physrevb.85.035409 [ * * , ( ) ] link:\doibase 10.1103/physrevb.94.081110 [ * * , ( ) ] link:\doibase 10.1103/physrevb.90.155113 [ * * , ( ) ] link:\doibase 10.1103/physrevlett.104.157201 [ * * , ( ) ] link:\doibase 10.1103/physreve.90.013308 [ * * , ( ) ] link:\doibase 10.1103/physrevb.91.184507 [ * * , ( ) ] link:\doibase 10.1103/physrevb.89.195147 [ * * , ( ) ] link:\doibase 10.1103/physrevb.89.245124 [ * * , ( ) ] http://dx.doi.org/10.1038/nphys2348 [ * * , ( ) ]

there is an enormous amount of information that can be extracted from the data of a quantum gas microscope that has yet to be fully explored . the quantum gas microscope has been used to directly measure magnetic order , dynamic correlations , pauli blocking , and many other physical phenomena in several recent groundbreaking experiments . however , the analysis of the data from a quantum gas microscope can be pushed much further , and when used in conjunction with theoretical constructs it is possible to measure virtually any observable of interest in a wide range of systems . we focus on how to measure quantum entanglement in large interacting quantum systems . in particular , we show that quantum gas microscopes can be used to measure the entanglement of interacting boson systems exactly , where previously it had been thought this was only possible for non - interacting systems . we consider algorithms that can work for large experimental data sets which are similar to theoretical variational monte carlo techniques , and more data limited sets using properties of correlation functions . _ introduction _ cold atom experiments provide a platform in which the many body physics of explicitly set hamiltonians can be measured directly . one experimental device used in cold atom experiments is the quantum gas microscope . direct measurement of magnetic order and dynamic correlations is feasible with such experimental systems @xcite . however , the full information provided from a quantum gas microscope is not limited to simple real space observables . a reconstruction of a bosonic quantum wave function is not only possible , but tractable . a similar reconstruction is feasible for a systems of fermions , but with a few limitations ( as will be discusssed ) . for a low temperature gapped system ( and all zero temperature systems ) the distribution of configurations generated from a quantum gas microscope is given by @xmath0 , and for finite temperature system the distribution is given by the diagonal elements of the finite temperature density matrix @xcite . other types of wave function tomography have also been considered previously @xcite , and the techniques considered here for the quantum gas microscope should be considered an alternative , especially for cases in which one is interested in many - body systems . the ideas presented here are adapted from the long standing and widely used literature of quantum monte carlo research as well as new ideas from the machine learning community @xcite . we are able to describe in this work how measurement of difficult quantities , such as real space quantum entanglement , can be made . this process blends theory and experiment providing new insights in both directions . _ from experiment to theory _ in this section we consider how to expand the current analysis of quantum gas microscope data and develop theoretical constructs for which we can develop detailed information about quantum systems . we consider two types of wave function tomography , which is also known in the literature as quantum state tomography . the methods we present include a general approach and an approach for situations in which the amount of data that can be generated is limited . _ wave function tomography _ in the limit of infinite samples from a quantum gas microscope , it is possible to recreate the full bosonic or fermionic wave functions without approximation under very general conditions . in fig . [ fig : recon ] we have illustrated how a single particle wave function might be reconstructed from varying number of snapshots , and what this implies for many particle systems . this process is limited by the number of samples that can be generated experimentally and the number of variational parameters that we can reasonably optimize ; this is directly analogous to optimizing wave function with variational monte carlo @xcite . generally quite complicated wave function forms can be optimized @xcite . to develop practical tools we consider the variational monte carlo framework which can be applied to _ ab initio _ systems and lattice simulations @xcite . real space variational monte carlo is based on generating configurations in real space from a trial wave function . these configurations are used to evaluate a cost function , that often involves the system hamiltonian , from which a set of variational parameters are optimized . there are several widely used optimization techniques including variance and energy optimizations @xcite , as well as wave function overlap optimization @xcite . since initial configurations are generated from an approximate guess wave function , variational monte carlo proceeds in iterations , during which new configurations are generated from the current best wave function . the main idea in this work is that the steps to generate new configurations in variational monte carlo can be replaced by the data generated from a quantum gas microscope . the approach is different from standard variational monte carlo as the generated snapshots from the quantum gas microscope are directly sampled from the wave function of interest and therefore there is no need to run several iterations . the question then becomes what type of variational parameters can be optimized and how many snapshots are needed . we discuss below the large data limit and the small data limit . for the large data limit , there is no difference applying the technique to bosons or fermions , except that an antisymmetric variational wave functions must be used for systems of fermions . we limit the discussion mainly to zero temperature / low temperature experiments except for some comments at the end about dealing with density matrices instead of wave functions . _ large data limit _ in the large data limit , one can proceed to run wave function optimization routines , as discussed above , on a set of snapshots generated by a quantum gas microscope . there are many available libraries and codes in which these optimizations can be done , however some expertise is often helpful . there are several strategies that that one can use for selecting variational parameters for continuum and lattice hamiltonians . in our previous quantum monte carlo work we directly make use of wave function optimization @xcite . with our variational monte carlo tools we allow for the optimization thousands of variational parameters @xcite . for bosons we generally only optimize two - body and three - body jastrow terms , which are suitable for a wide range of systems , as will be discussed in relation to the no - nodes theorem @xcite . the form of a jastrow wave function can be written as @xmath1 for a system of bosons and @xmath2 for a system of fermions . for these wave function , @xmath3 is the jastrow and @xmath4 is an antisymmetric function of the particle coordinates . the coordinates @xmath5 , and @xmath6 is the space and spin coordinates of a single particle . often one and two - body jastrow terms are used which is written as , @xmath7 the one - body jastrow , @xmath8 , is generally a set of functions centered around fixed nuclei or lattice sites . a two - body jastrow , @xmath9 , consists of pairwise terms between all quantum particles @xcite . these functions depend only on the distance between quantum particles , and in our variational monte carlo studies use on the order of 10 - 20 variational parameters that are the knots of a spline function in real space . three - body jastrow terms can be much more complicated and depend on distances and angles between all triplets of quantum particles . however these can be fully optimized as well . for fermions we generally optimize more complicated forms , that involve backflow and multi - determinants @xcite . in systems that are homogenous for which the jastrows factors can be replicated for all lattice sites or atoms , there might be only a few dozen parameters to optimize . generally only a few hundred configurations are needed in such simulations ( or less depending on the situation ) to optimize the variational parameters . for fermions we generally try to include many more variational parameters through multi - determinant expansions . when optimizing a thousand or more variational parameters we generally try to include 10,000 - 100,000 snapshots for the optimizations . the need for many configurations comes not only from the the number of variational parameters we are trying to optimize , but also that the determinant parameters in a determinant expansion become very small , and require many samples in order to resolve their values above the inherent noise . as mentioned previously , other types of variational parameters can be included in an optimization . in principle even a tensor network @xcite would be an alternative form that can be optimized , although it would require expanding on the techniques discussed here . we also mention here , in connection with the machine learning techniques in later sections , that it is theoretical possible to optimize variational parameters of a neural network to learn a quantum wave function , both with variational monte carlo and a quantum gas microscope . advances with symmetry functions have made it feasible to learn very high dimensional potential energy landscapes @xcite , and we suggest here that it is possible to use the same symmetry functions in order to have a neural network learn a wave function of bosons . while in principle it is possible to learn fermionic wave functions with neural networks , enforcing the antisymmetry requires some additional developments . _ small data limit for bosons _ alternatives exist for data limited experiments beyond the full wave function tomography discussed in the previous section . the full power of a quantum gas microscope on a system of bosons can be best understood from the feynman `` no node '' theorem . this is a statement about how a boson ground state quantum wave function in coordinate representation is positive definite @xcite . feynman was able to show that this holds under a broad set of conditions which includes that no external rotations be applied . because of time reversal symmetry , the wave function can be chosen to be real , and the `` no node '' theorem can be shown to follow from a procedure that always lowers the energy of a system by removing nodes . virtually all boson ground states that do not involve applied magnetic fields can realize a wave function with no nodes which includes many exotic states . however , only for bosons does the wave function amplitudes and wave function probability distribution have identical information . the probability distribution of bosons in coordinate space @xmath10 is what a quantum gas microscope would measure in the limit of an infinite number of snapshots of a quantum system . in other words a quantum microscope can be used to sample a many - body wave function of interest according to its probability distribution @xmath11 after which @xmath12 can be determined by taking a square root of the probability distribution . this is not generally true in fermionic systems or complex wave functions , where the sign / phase of a wave function can not be extracted from the probability distribution . in very large systems , as with many cold atom experiments where there can be more than a million quantum particles @xcite , many snapshots would be needed as more variational degrees of freedom are needed to represent a wave function . such complications are compounded where there are multiple quantum phases present due to differences between the environment in the middle of a trap versus the edge of the trap @xcite . historically there have been different approaches to further study such systems through their correlation functions . jastrow factors that involve 1 , 2 and 3 body functions are regularly used to either minimize the energy ( as discussed in the previous section ) or to match known correlation functions . matching correlation functions by optimizing jastrow variational parameters is one possible approach , but one could also use other techniques such as those related to the hypernetted - chain approximation @xcite . the benefit of correlation matching is that it allows one to focus on the phase of interest with high precision as the low order correlation functions may be determined with only a very few number of snapshots . to understand correlation matching , we start by considering a set of samples from a quantum gas microscope , \{s@xmath13 ... s@xmath14}. the density can be estimated from the snapshots and should match the corresponding one body correlation function of the wave function given by , @xmath15 . the two body correlation function can be generated by considering the distance between all pairs of quantum particles over all snapshots , as for example in fig . [ fig : pair ] and fig . [ fig : noise ] . the corresponding quantity to be matched by a wave function is given by @xmath16 similarly , the three body correlation function can be tabulated from the experimental data and a jastrow factor can be optimized . the optimization should be done simultaneously for all variational parameters and all correlation functions . for an isotropic system ( or an isotropic phase in the middle of a trap ) , the correlation functions can be reduced in dimensionality . the pair correlation function can be turned into the radial distribution function , @xmath17 . excellent approximate wave functions have been generated for various quantum systems , with even just a two body jastrow term @xcite . to understand the limit in which the correlation function approach becomes exact and when it should be accurate , we can consider the problem of fitting to a very high dimensional n - body jastrow term . if accurate n - body correlation data is measured and tabulated for a system , then an n - body jastrow term can be computed . in the case of bosons , the n - body jastrow term is the exact full wave function of the system , up to statistical errors and limitations in the variational parameters . this is because a nodeless wave function , as previously mentioned , has the property that the probability distribution can be used to generate the wave function amplitudes by @xmath18 . thus we expect the accuracy for our wave function to increase and eventually converge by increasing the order of the correlation functions used . for a system with a very large homogenous region , it may be possible to fit several low order correlation functions with just a single snapshot as demonstrated in fig . [ fig : pair ] and fig . [ fig : noise ] . a typical cold atoms system might have a few hundred thousand bosons of which a single snapshot includes a number of pairs proportional to @xmath19 and triplets proportional to @xmath20 . for a system of a few thousand particles , this in some situations will generate enough data such that low order correlation functions may be tabulated with small error bars with only a few snapshots . the effectiveness of this approach will depend upon the nature of the correlations and the level of inhomogeneity . the above procedure does not work for fermions , unless an antisymmetric wave function is assumed , and only the jastrow factor is optimized . this is a widely used approximation in variational monte carlo . for example a determinant of plane - wave orbitals is often assumed for the antisymmetric part of a wave function when studying interacting fermi - liquids @xcite . an exception to this is fermions in 1d as the nodes of a 1d system are known exactly . the nodal surface of a system of n fermions in one dimension has dimensionality for n-1 , which is completely determined by antisymmetry of the wave function . only in 1d this true , and it implies for the ground state that the nodal surface is defined when fermions coincide with each other . therefore as long as we use for the antisymmetric part of the wave function a term with the exact nodes , which we can do in 1d , then optimizing a jastrow factor is as exact as the boson correlation matching . approximate antisymmetric wave functions in higher dimensions can be used to generate approximate results , which in many cases may be accurate for a system of interest . _ quantum entanglement _ using the wave function tomography in the previous section provides experimental access to otherwise difficult to measure quantities , which includes the quantum entanglement of many particle systems . real space quantum entanglement has proven to be important in many modern theoretical studies of both high energy and condensed matter physics @xcite . an experimental measurement of quantum entanglement can provide information about the details of the wave functions for physical systems that we have yet to understand and would be of interest in many different systems , including fermi liquids @xcite , topological phases @xcite and even molecular systems @xcite . the entanglement entropy , the renyi entropy @xcite , and the entanglement spectrum @xcite , are three of the most widely used quantities calculated from a spatial reduced density matrix . the spatial reduced density matrix is determined by splitting the system into two parts , regions a and b , where a density matrix in region a is given by integrating out all the degrees of freedom in region b. this is written as follows , @xmath21 the entanglement spectrum is defined as the eigenvalues of @xmath22 , while the nth order renyi entropy is given as @xmath23.\ ] ] the entanglement entropy is defined as @xmath24.\ ] ] there are several techniques that have been proposed to measure quantum entanglement in cold atom systems @xcite . recent experiments have been able to realize one of these techniques @xcite , however they were limited to a small number of particles and have not yet been able to address many predictions of interest @xcite and disagreements such as the nature of the widom conjecture in interacting systems @xcite . one of the techniques to measure quantum entanglement , which has been referred to as the _ the fluctuation technique _ @xcite is derived from the properties of quantum entanglement of non - interacting systems . non - interacting systems have the special property that the entanglement entropy as well as the full entanglement spectrum can be determined by how particles fluctuate between two regions . entropy is @xmath25 , which is equal to the largest entanglement two non - interacting particles can observe . for lattices with more sites , the entanglement due to mirror correlations can increase past the limit for non - interacting particles . a wave function with mirror correlations for 16 lattice sites in each half has an entanglement equal to @xmath26 . the fluctuation method estimates a zero entanglement , where as the techniques discussed here have the potential to measure the exact entanglement . ] a quantum gas microscope can be used to experimentally measure the fluctuations of particles in a cold atoms systems over any spatial partitions . however , this technique can only serve as a lower bound of quantum entanglement when there are many body interactions . the fluctuations make up only part of the entanglement , as both fluctuations and correlations are needed to determine the quantum entanglement @xcite . examples of systems in which the entanglement is due entirely to many body correlations are illustrated in fig . [ fig : entex ] and fig . [ fig : entex1 ] . the system in fig . [ fig : entex1 ] , which represents a wave function with mirror correlations , is one of the most strongly entangled wave functions that can be created . it is important to emphasize that although the fluctuation method does not capture all the quantum entanglement for an interacting many body system the data from the quantum gas microscope contains all the information needed to determine the entanglement properties . _ swap operator _ to understand how to measure entanglement of an interacting system we rely on the use of the swap operator which is an estimator used to calculate renyi entropies with quantum monte carlo @xcite . the operation of the swap operator is defined on a wave function that is written in terms of complete basis sets of regions a and b , @xmath27 and @xmath28 , as follows @xmath29 . the swap operator is defined in a space of the wave function that is a tensor product with itself as follows @xmath30 the expectation value of the swap operator is related to @xmath22 by the following , @xmath31 this operator can be sampled with independent configurations generated from @xmath32 and the results can be used to calculate the renyi entropy , s@xmath33 = @xmath34 . in terms of the real space coordinates the expectation value of the swap operator is given by eq . [ eqn : estimator ] . @xmath35 from these definitions the operator can be identified as @xmath36 in these equations we have used the notation @xmath37 , which are the real space coordinates . the swap operator is performed over two sets of coordinates , and thus the subscripts are used to identify which set of coordinates to use . all the coordinates in region a are associated with @xmath38 and all the coordinates in region b are associated with @xmath39 . once @xmath12 has been generated , either through full wave function tomography , or correlation function matching , it is then straightforward to generate new configurations using @xmath12 , and evaluating the estimator in eq . [ vmcop ] , by replacing @xmath40 with @xmath12 . we have tested this process in previous works which includes fermi liquids and molecular systems @xcite , and other authors have done related studies on systems of bosons @xcite . further possibilities of evaluating the full entanglement spectrum are possible as described in other qmc work @xcite . _ from theory to experiment : phase identification with neural networks and density functional theory _ in this section we consider going in the other direction , in which theoretical tools are first developed and then applied to quatum gas microscope data . recent developments in artificial neural networks have shown that phases can be learned from quantum monte carlo snapshots of a system @xcite . the idea is to generate quantum monte carlo configurations from different phases that are known theoretically and train a neural network to recognize the different phases . once trained the neural network serves as a tool to identify quantum phases , which can be applied to the data from a quantum gas microscope . in recent works @xcite the details of how to do some phase discrimination has been discussed in detail . advances for applying these machine learning techniques to fermions has produced promising results . the original technique @xcite and has since been adapted to green s functions for fermion systems @xcite , and recently to more general data @xcite . there are tradeoffs of such an approach compared to what would be a more straightforward calculation of an order parameter , or in comparison to the tomographic methods described in this work . advantages include that one does not have to know the order parameter to begin with , it works inherently at zero temperature and finite temperature , and one does not even have to know what the hamiltonian for the system in which data is being generated . the negatives are that one does not know how transferable learning between different hamiltonians or even between data at different temperatures . neural networks should be considered good at interpolation and bad at extrapolation . if a phase of matter has not been included in a training set , then it is unlikely a neural network will produce meaningful results when asked to identify such a phase . in comparison to the wave function tomography presented in this work , some of the features are similar . a finite temperature tomography requires density matrix optimization @xcite , which is possible but requires one to extend the techniques presented in this work . for the wave function tomography , one must include enough variational degrees of freedom to learn a wave function properly , where as with the neural networks , one has to train on all possible phases that a new system might observe . in both cases some care is required before applying the techniques . we also note that density functional theory for cold atom systems has recently been developed for the purposes of theoretical modeling @xcite . this approach can also be applied to gas microscope data of cold atom systems . the one particle correlation function is the density of a system which can be directly estimated from a quantum gas microscope . in the same manner as described for the neural networks , one can use the best functional developed for a system of interest , and map out the phase diagram with energies generated from density functional theory . thus one can test different approaches ranging from wave function tomography , dft analysis , and phase learning from neural networks to get a very detailed picture of a system of interest . _ conclusions _ we presented several ideas for studying quantum gas microscope data with the main goal of demonstrating that such data can be used for full wave function tomography on a wide range of quantum systems . the wave function tomography approaches facilitate experimental measures of what are generally hard quantities to measure , such as the quantum entanglement . the two techniques presented here can be applied in different scenarios related to the amount of data that can be generated in an experiment . both techniques take advantage of the fact that many body correlations and fluctuations are encoded in the quantum gas microscope snapshots . with this analysis future quantum gas microscope experiments should be able to elucidate many of the exciting features that are hidden within a quantum wave functions .

As state and local police prepare their security plans for this year’s Boston Marathon, runners are already being warned about new dos and don’ts for the race, specifically around any area that is part of Marathon events. Marathon officials said they would issue a new, warmer type of cape for race finishers who will have a longer walk to get their bag of clothes after the race. The Boston Athletic Association, which organizes the race, issued a series of new rules and restrictions today in a mass e-mail. Runners who like to run in costume won’t be allowed to wear anything that covers their face or bulky clothes; strollers won’t be allowed at the Athletes’ Village near the starting line in Hopkinton or around the finish line on Boylston Street; neither will backpacks, glass containers, any container that can carry more than 1 liter of liquid, vests with pockets, or suitcases and rolling bags. Advertisement - Continue Reading Below People will also be forbidden from wearing backpacks that carry water — such as CamelBaks. Props like sports and military equipment will be banned, as well as flags or signs that are wider than 11 inches and longer than 17 inches. Bags, used in the past by runners to carry clothes and other personal items, will be banned on the buses that carry runners from Boston Common to Hopkinton, where the race starts. And no bags will be brought by those buses back to Boston. Instead, runners can check bags with personal items on Boston Common, take the bus to Hopkinton, run back, and then retrieve their bags. Runners can carry fanny packs and fuel belts. The association said there would be changes to the finish line, including three areas just before Arlington Street where runners and others can exit. “More information on these exit areas will be forthcoming,” the e-mail said. The new restrictions also boded ill for “bandits” — the unauthorized runners who join the race every year. The rules said that this year bandits would be “subject to interdiction.” “We are aware that many people want to participate in some way in this year’s Boston Marathon as a display of support, but we ask that those who are not official participants to refrain from entering the course for the safety of the runners and themselves,” the e-mail said. “Similarly, units or groups such as military ruck-marchers and cyclists, which have sometimes joined on course, will not be allowed to participate,” the e-mail said. “For the 2014 Boston Marathon, with an increased field size and for everyone’s safety, we will work with public safety officials to ensure that we preserve the exceptional race day experience that makes the Boston Marathon an icon in the world of sport while making race day safe and enjoyable for all,” the e-mail said. The last running of the Marathon — normally an upbeat celebration of world-class athletes’ prowess and average runners’ determination — turned tragic when twin terror bombs went off near the finish line. The explosions killed three people and wounded more than 260 others. One suspect in the bombings is dead and the other is awaiting a federal trial that could bring him the death penalty. ||||| The Boston Athletic Association has indicated it will crack down on bandit runners and even ROTC marchers who don’t have registration numbers, according to an email released today that also bans participants from bringing bags to this year’s Boston Marathon as part of higher security measures following the 2013 bombings. The article you requested has been archived All coverage within bostonherald.com from the last 14 days remains free of charge. Articles do not always include original photos, charts or graphics. » Click here to search for this article within the archive.

– The Boston Athletic Association is responding to last year's Marathon tragedy with an almost draconian set of new rules on competitors and spectators, the Boston Globe reports. According to a mass email sent out yesterday, the following are all forbidden this year: Bulky clothes, or costumes that conceal a runner's face Strollers at the start or finish line Backpacks, CamelBaks, and the bags runners often use to carry clothes and personal effects Glass containers Suitcases and rolling bags Vests with pockets, except lightweight running vests Props, including sports and military equipment Flags or signs wider than 11" or longer than 17" The race will be also cracking down on "bandits," the thousands of unauthorized runners who always jump into the action. The BAA said that anyone without an official number would be "subject to interdiction." That would include, the Boston Herald notes, the dozens of ROTC cadets who traditionally march in the race. A spokesman said the BAA hasn't decided yet whether to make an exception for the marchers.

an edge coloring of a graph @xmath0 with colors @xmath1 is called an interval @xmath2-coloring if for each @xmath3 there is at least one edge of @xmath0 colored by @xmath4 , the colors of edges incident to any vertex of @xmath0 are distinct and form an interval of integers . the concept of interval edge colorings was introduced by asratian and kamalian @xcite . in @xcite they proved that if a triangle - free graph @xmath9 has an interval @xmath2-coloring , then @xmath10 . furthermore , kamalian @xcite showed that if @xmath0 admits an interval @xmath2-coloring , then @xmath11 . giaro , kubale and malafiejski @xcite proved that this upper bound can be improved to @xmath12 if @xmath13 . for a planar graph @xmath0 , axenovich @xcite showed that if @xmath0 has an interval @xmath2-coloring , then @xmath14 . in @xcite interval edge colorings of complete graphs , complete bipartite graphs , trees and @xmath15-dimensional cubes were investigated . the @xmath16-completeness of the problem of existence of an interval edge coloring of an arbitrary bipartite graph was shown in @xcite . in papers @xcite the problem of existence and construction of interval edge colorings was considered and some bounds for the number of colors in such colorings of graphs were given . in particular , it was proved in @xcite that if a connected graph @xmath0 admits an interval @xmath2-coloring , then @xmath17 , and if @xmath0 is a connected bipartite , then the upper bound can be improved to @xmath6 , where @xmath7 is the maximum degree in @xmath0 and @xmath8 is the diameter of @xmath0 . in this paper we show that these upper bounds can not be significantly improved . all graphs considered in this paper are finite , undirected and have no loops or multiple edges . let @xmath18 and @xmath19 denote the sets of vertices and edges of @xmath0 , respectively . the maximum degree in @xmath0 is denoted by @xmath20 , the chromatic index of @xmath0 by @xmath21 and the diameter of @xmath0 by @xmath22 . a partial edge coloring of @xmath0 is a coloring of some of the edges of @xmath0 such that no two adjacent edges receive the same color . if @xmath23 is a partial edge coloring of @xmath0 and @xmath24 , then @xmath25 denotes the set of colors of colored edges incident to @xmath26 . let @xmath27 denote the largest integer less than or equal to @xmath28 . given two graphs @xmath29 and @xmath30 , the cartesian product @xmath31 is a graph @xmath32 with the vertex set @xmath33 and the edge set @xmath34 @xmath35 and @xmath36 or @xmath37 and @xmath38 . the set of all interval colorable graphs is denoted by @xmath39 @xcite . for a graph @xmath40 , the greatest value of @xmath2 , for which @xmath0 has an interval @xmath2-coloring , is denoted by @xmath41 . the terms and concepts that we do not define can be found in @xcite . + we will use the following results . [ mytheorem1]@xcite . @xmath42 for any @xmath43 . [ mytheorem2]@xcite . @xmath44 for any @xmath45 . [ mytheorem3]@xcite . if @xmath46 , then @xmath47 . [ mytheorem4]@xcite . ( 1 ) if @xmath0 is a connected graph and @xmath40 , then @xmath48 . \(2 ) if @xmath0 is a connected bipartite graph and @xmath49 , then @xmath50 . [ mytheorem5 ] for any integers @xmath51 , there is a connected graph @xmath0 with @xmath52 , for the proof we construct a graph @xmath61 which satisfies the condition of the theorem . we define a graph @xmath61 as follows : @xmath62 . clearly , @xmath61 is a connected graph of diameter @xmath8 and it can be verified that if @xmath89 , then @xmath84 is an interval @xmath77-coloring of the graph @xmath90 , if @xmath91 , then @xmath84 is an interval @xmath92-coloring of the graph @xmath93 and @xmath84 is an interval @xmath94-coloring of the graph @xmath61 for @xmath95 . this implies the necessary lower bounds for @xmath96 . @xmath97 it can be verified that @xmath165 is an interval @xmath141-coloring of the graph @xmath101 , thus @xmath164 and @xmath176 . on the other hand , from theorem [ mytheorem4 ] we have @xmath132 , hence @xmath177 . @xmath97

an edge coloring of a graph @xmath0 with colors @xmath1 is called an interval @xmath2-coloring if for each @xmath3 there is at least one edge of @xmath0 colored by @xmath4 , the colors of edges incident to any vertex of @xmath0 are distinct and form an interval of integers . in 1994 asratian and kamalian proved that if a connected graph @xmath0 admits an interval @xmath2-coloring , then @xmath5 , and if @xmath0 is also bipartite , then this upper bound can be improved to @xmath6 , where @xmath7 is the maximum degree in @xmath0 and @xmath8 is the diameter of @xmath0 . in this paper we show that these upper bounds can not be significantly improved . keywords : edge coloring , interval coloring , bipartite graph , diameter of a graph

SHARE THIS ARTICLE Share Tweet Post Email Only days after Donald Trump took the oath of office, the head of his hotel-management company outlined hopes for an ambitious expansion across the U.S., raising new questions about potential conflicts between his business and the presidency. Trump Hotels Chief Executive Officer Eric Danziger suggested the company’s broad U.S. ambitions while saying it shelved plans for expansion in China, where the president’s comments have already led to rocky diplomatic relations. “There are 26 major metropolitan areas in the U.S., and we’re in five,” Danziger said after a panel discussion Tuesday at the Americas Lodging Investment Summit in Los Angeles. “I don’t see any reason that we couldn’t be in all of them eventually.” Meanwhile, new membership fees at Trump’s Mar-A-Lago club have doubled to $200,000, Bernd Lembcke, its managing director, said in a Wednesday e-mail, first reported by CNBC. The Palm Beach, Florida resort, which Trump has called “The Winter White House,” was the location of the president’s New Year’s Eve celebration with family and supporters. He tweeted a photo of himself writing his inaugural speech at the resort last week. Most ethics experts, including the agency that monitors such matters in the federal government, have said Trump should divest his holdings entirely. The expansion -- which has the potential to benefit from Trump’s actions and profile as president -- could spark further controversy. Democratic lawmakers have also called on Trump to divest his businesses to avoid conflicts of interest, and he has refused to do so. Perceived Conflict Even if his business activities are considered legal, they certainly heighten the perceived conflict, according to Wendy Patrick, who teaches business ethics at San Diego State University. “Although he is now officially the leader of the free world, Donald Trump remains both a businessman and a brand,” Patrick said in an e-mail. “The fact that the hotel chain that bears his name is seeking to expand within the United States raises questions of both law and ethics.” Instead of divesting, Trump has turned over management of his company, the Trump Organization, to his two elder sons and pledged no new foreign deals during his term. He has financial ties to $3.6 billion of assets in about 20 countries and more than $600 million of debt. Jennifer Rodstrom, a spokeswoman for Trump Hotels, didn’t immediately respond to a call and e-mail seeking comment. Tripling Total Trump Organization officials will ask a Washington attorney and a veteran executive in President Trump’s businesses to help ensure separation between the White House and the family business, according to a person familiar with the matter. Bobby R. Burchfield will become the business’s chief compliance counsel and George A. Sorial will be its chief compliance officer, the person said. Having Trump hotels in 26 cities would triple the current total. Trump’s company manages eight namesake hotels in the U.S., some of which the Trump family owns. Danziger, who joined Trump Hotels in August 2015, said that Trump Hotels is considering opening luxury properties in Dallas, Seattle, Denver and San Francisco, where he started his career in 1971 as a bellman at a Fairmont hotel. Watch Next: Will the Trumps Cash In at the White House? Will the Trumps Cash In at the White House? New Trump-branded luxury hotels would be only in major cities, while the company’s new lower-priced Scion-branded properties would operate in smaller cities, Danziger said during the panel discussion. The first Scion hotel will open this year, he said. Domestic Emphasis Shortly before the Nov. 8 election, Danziger told media in Hong Kong that the company, as part of an international expansion, had plans for hotels in China -- a country Trump has repeatedly criticized over trade deals and U.S. job losses. “That’s pretty much off,” Danziger said during the panel discussion, drawing laughter from the audience. Danziger declined to say where the first Scion hotel will be located. Planned Scion hotels range in size from 72 rooms to 800, he said. “Both brands and any others we create will have a domestic emphasis for the next four or eight years,” he said, also drawing laughter. Trump’s hotel business consists mainly of branding and management contracts, and the expansion may involve converting existing properties. His Washington property has become the focus of controversy because of concern that foreign-government patronage could violate the constitutional ban on emoluments, and because no elected official is allowed to benefit from the lease on the building, which is rented from the federal government. Besides the four-month-old Washington hotel, there are two properties in New York, one in Chicago, one in Las Vegas, and the Trump National Doral golf resort in Miami. A new luxury hotel in Vancouver is set to have its grand opening next month. ||||| President Trump’s Mar-a-Lago Club in South Florida has doubled its new-member fees to $200,000 due to growing interest since the election, a major spike that is already drawing criticism that the president is profiting off his rise to the White House. The increase, first reported by CNBC and confirmed by club managing director Bernd Lembcke in a Bloomberg News interview, could boost the revenue of the Palm Beach club Trump has called the “winter White House.” It could also directly benefit his private fortune because he has refused to divest his business holdings while in the Oval Office. The increase restores the Mar-a-Lago price to its pre-recession level, before economic troubles made it harder for the club to attract new members. Mar-a-Lago, which Trump purchased in 1985, encompasses more than 17 acres and operates in two moneymaking ways — as a private club open to dues-paying members and as a venue that can be rented for weddings and events. Trump has reported making millions from Mar-a-Lago, with revenue rising during his presidential campaign, according to his federal financial disclosures. The club received more than $29.7 million in “resort-related revenue” between July 2015 and May 2016, according to his most recent disclosure, while an earlier filing by Trump reported the club taking in $15.5 million in resort revenue between January 2014 and July 2015. Trump Organization executives did not respond to requests for comment Wednesday. [Inside Trump’s Palm Beach castle and his 30-year fight to win over the locals] Since his election victory, Mar-a-Lago has assumed a prized role in Trump’s presidency, rivaling Trump Tower as a focal point of his lifestyle and ambitions. The club’s deep-pocketed clientele are offered the opportunity to encounter the president when he is relaxing at his vacation home. Trump, his family, major donors and other supporters gathered at the club for a glitzy celebration on New Year’s Eve. Club membership, its website says, offers “the highest privileges and an elite lifestyle reserved for a select few.” The club is “certainly a lot more crowded now that he’s president,” Jeff Greene, a Florida billionaire and Mar-a-Lago member, told The Washington Post on Wednesday. At a recent dinner, Greene said, the crowds were massive, adding, “It never used to be that packed.” As part of Trump’s pledge to separate his business from his presidency, his son Donald Jr. has been named the official director of the club, according to a Florida business filing on Monday. The club once charged new members $200,000 for initiation fees but greatly reduced them, to $100,000, during the recession. The club’s more than 400 members must also pay $14,000 a year in dues. Hosting a big gala at the club can range from $100,000 to $300,000. When the club faced $120,000 in unpaid Palm Beach fines from a dispute over the height of a flagpole, Trump helped pay for it with a $100,000 donation from his personal foundation. [Trump company names ethics advisers, but critics call it an ‘impossible spot’] The price jump was slammed by ethics watchdogs, who have criticized Trump’s lack of separation between his private finances and public power. Norm Eisen, a former chief ethics adviser to the Obama administration who is part of a lawsuit accusing Trump of violating a constitutional provision barring presidents from taking payments from foreign governments, called the Mar-a-Lago move “naked profiteering that is more like something out of the era of Louis XVI.” Mar-a-Lago’s price jump was revealed the same week that another corner of the Trump business empire voiced its growing ambitions. Speaking of a planned expansion, Trump Hotels chief executive Eric Danziger told a Los Angeles investment summit on Tuesday, “There are 26 major metropolitan areas in the U.S., and we’re in five. . . . I don’t see any reason that we couldn’t be in all of them eventually.” His comments were reported by Bloomberg. [An early test of Trump’s ethics pledge is a glittering new foreign tower] Greene, a Hillary Clinton supporter and Democratic candidate in Florida’s 2010 Senate primary, said the price jump could be a natural reflection of the club’s soaring demand. “The reality is most country clubs can’t” raise prices so quickly, Greene said. “But Donald Trump is the board of directors, so if he decides, ‘I’ll let people pay more dues,’ he can do it,” Greene said. He acknowledged that the “optics” of the club raising its rates during Trump’s presidency looked disconcerting. But “I don’t think Donald is a guy who cares very much about optics,” Greene added. “He does what makes sense to him, and he doesn’t care what anyone else thinks.” Alice Crites contributed to this report. ||||| The Trump administration faces a particularly daunting task in confronting potential conflicts of interest, or the appearances of such, given the president’s refusal to legally separate himself from his business. He has instead handed it to his children — a decision that has drawn the ire of ethics experts. The White House also announced on Wednesday that it had appointed a legal team to handle compliance and ethics matters. The team will serve under Donald F. McGahn II, the White House counsel, and consists of four lawyers, including Stefan C. Passantino, who has specialized in campaign compliance and election law issues for clients like Newt Gingrich and J. Dennis Hastert, both former Republican House speakers. Mr. McGahn said in a statement that the establishment of the team “reflects the importance of ethics compliance to the President and this administration.” In addition to Mr. Burchfield’s appointment, the Trump Organization also announced on Wednesday that George Sorial, a longtime executive, would be its chief compliance counsel. Mr. Burchfield served for decades as a Republican Party legal adviser, with clients that included former Representative Tom DeLay, Republican of Texas, when he was investigated on allegations of campaign finance violations and money laundering. Mr. Burchfield also serves as the chairman of Crossroads GPS, the so-called dark money group founded by Karl Rove, the White House adviser during the administration of former President George W. Bush. Trevor Potter, a former Republican chairman of the Federal Election Commission, commended Mr. Burchfield as a “very good lawyer” and a “competent litigator,” but said a better choice, from a conflicts standpoint, would have been a nonpartisan federal judge. “He is very much a Republican insider,” said Mr. Potter, who now leads the Campaign Legal Center, a nonprofit focused on campaign finance. “He was undoubtedly picked in part because he has a history of being a reliable Republican lawyer, a partisan who has represented the party in a number of suits. So he is not an outsider.” Mr. Burchfield declined to comment on Wednesday. A partner in the Washington office of the law firm King & Spalding, he will continue with his practice, and the Trump Organization will essentially serve as a client. His corporate clients have included United Airlines and the N.F.L., and he has at times offered ethics compliance advice to major corporations and individuals, a lawyer at his firm said. Elliot S. Berke, a Republican ethics lawyer who has shared clients at times with Mr. Burchfield, including Mr. DeLay, said Mr. Burchfield was not the kind of lawyer who would simply sign off on what his clients asked. “He is an absolute master on complex ethics and compliance issues,” Mr. Berke said. “He has the ability to be impartial and fair. He would see that as his obligation as a lawyer to do so.” ||||| These are America's five richest presidents 9:48 AM ET Thu, 19 Jan 2017 | 01:47 A membership at Mar-a-Lago now includes a chance to mingle with the 45th president. Trump plans to use the resort as his occasional "Winter White House." He has visited twice since his election — first for Thanksgiving and then over the Christmas and New Year holidays. There's no way of knowing whether demand for memberships has grown. The initiation fee for Mar-a-Lago had been $100,000 since 2012, when it was cut from $200,000. People close to the resort said the fee was reduced following a decline in memberships after the Bernie Madoff scandal, which claimed many wealthy Palm Beach victims. On top of the initiation fee of $200,000 plus tax, members also pay $14,000 a year in annual dues (plus tax). The 20-acre resort has a main mansion with more 100 rooms, along with private quarters for Trump and his family. It also has a beach club, pools, restaurant, tennis courts and a 20,000-square-foot ballroom that Trump built for events. Trump has resigned his position as CEO of the Trump Organization and put his assets into a trust. It will now be run by his two sons. Details of the trust and Trump's income from the company remain unclear. While the company has said it will stop any new deals overseas, it will continue to expand in the U.S. And the Mar-a-Lago price hike shows that it can also grow through higher fees and rates. At a conference in Los Angeles on Tuesday, the chief executive of Trump Hotels said the company has room to expand in the U.S. "There are 26 major metropolitan areas in the U.S., and we're in five," CEO Eric Danziger said, according to Bloomberg. "I don't see any reason that we couldn't be in all of them eventually." A spokesman for Trump Hotels told CNBC that the company sees "significant growth opportunity in the United States for both our hotel brands." — CNBC's Christopher DiLella and Jacob Pramuk contributed to this report. Update: This story has been updated with a quote from Norm Eisen.

– Want to join the ranks of those allowed into Donald Trump's "winter White House"? You'll have to double what you would've spent in 2016 for a Mar-a-Lago membership fee, which was increased Jan. 1 from $100,000 to $200,000, sources "close to the resort" tell CNBC. Bernd Lembcke, the club's managing director, confirmed the price spike in an email Wednesday, per Bloomberg. And although Donald Trump Jr. has now reportedly been named the official director of the club in his father's stead, Norm Eisen—President Obama's former chief ethics lawyer and part of an advocacy group that's filed a lawsuit against Trump for violating the Constitution's Emoluments Clause—says what's going on at the Palm Beach, Fla., estate is nothing more than "naked profiteering" that would have been more befitting a kleptocrat like "Louis XVI." Mar-a-Lago is "certainly a lot more crowded now that he's president," one member concedes to the Washington Post. The club's fee had reached $200,000 in the past, but had been slashed back to $100,000—the CNBC sources say the cost was cut in 2012 after the Bernie Madoff hubbub, while Lembcke tells the New York Times that it was reduced in 2010 due to the recession. In addition to the reinstated $200,000 initiation fee, members must also pay $14,000 in annual dues (plus tax on the whole deal). But while one ethics watchdog rep calls the increased fee an "unacceptable" development that "demeans" the presidency, Lembcke tells the Times that plans for this price boost were put in place before the election. He does add that since Trump's win, there's been a "sudden surge" in application requests.

SECTION 1. SHORT TITLE. This Act may be cited as the ``Intercity Rail Infrastructure Investment Act''. SEC. 2. FINDINGS. Congress finds that-- (1) intercity passenger rail service is an essential component of an integrated national transportation system; (2) Amtrak must lessen its dependence on Federal operating support and instead enter into more sustaining partnerships with States, multi-State regions, and localities; (3) intercity passenger rail service can play a significant role in reducing traffic congestion, improve national ambient air quality standards, and lower fuel consumption; (4) since certain major rail corridors clearly meet the description of National Highway System principal arterial routes in section 103(b)(1) of title 23, United States Code, by serving major population centers, major travel destinations, and other intermodal transportation facilities, the corridors should be designated as part of the mapped National Highway System; (5) since intercity passenger rail service is often provided in the same corridor as, or in proximity to, a designated segment of the National Highway System or will improve the level of service on a National Highway System segment, the service should be eligible for funding under section 103(i) of title 23, United States Code; (6) States should be given the maximum flexibility in the use of Federal transportation funds provided under titles 23 and 49, United States Code, to provide-- (A) transportation systems that reflect local priorities; and (B) the highest quality most appropriate transportation services for citizens of the States; and (7) Federal law should not restrict the rights of States to use their Federal transportation allocation for intercity passenger rail service. SEC. 3. DESIGNATION OF CERTAIN CORRIDORS AS PART OF NATIONAL HIGHWAY SYSTEM. Section 103 of title 23, United States Code, is amended by inserting after subsection (b) the following: ``(c) Rail Lines and Related Facilities.--The National Highway System as designated pursuant to this section shall include the rail lines and related facilities owned or used by the National Railroad Passenger Corporation for the provision of intercity passenger service between Boston, Massachusetts, and Washington, District of Columbia (including the rail lines owned by the Corporation between Philadelphia, Pennsylvania, and Harrisburg, Pennsylvania, and between New Haven, Connecticut, and Springfield, Massachusetts); between New York, New York, and Albany, New York; between Albany, New York, and Buffalo, New York; between Washington, District of Columbia, and Richmond, Virginia; between Raleigh, North Carolina, and Charlotte, North Carolina; between Miami, Florida, and Tampa, Florida (through West Palm Beach, Florida, and Orlando, Florida); between Detroit, Michigan, and Chicago, Illinois; between Milwaukee, Wisconsin, and Chicago, Illinois; between St. Louis, Missouri, and Chicago, Illinois; between San Diego, California, and Sacramento, California (through Los Angeles, California, and Oakland, California); and between Eugene, Oregon, and Vancouver, British Columbia (through Portland, Oregon).''. SEC. 4. INTERSTATE RAIL COMPACTS. (a) Consent to Compacts.--Congress grants consent to States with an interest in a specific form, route, or corridor of intercity passenger rail service (including high speed rail service) to enter into interstate compacts to promote the provision of the service, including-- (1) retaining an existing service or commencing a new service; (2) assembling rights-of-way; and (3) performing capital improvements, including-- (A) the construction and rehabilitation of maintenance facilities; (B) the purchase of locomotives; and (C) operational improvements, including communications, signals, and other systems. (b) Financing.--An interstate compact established by States under subsection (a) may provide that, in order to carry out the compact, the States may-- (1) accept contributions from a unit of State or local government or a person; (2) use any Federal or State funds made available for intercity passenger rail service (except funds made available for the National Railroad Passenger Corporation); (3) on such terms and conditions as the States consider advisable-- (A) borrow money on a short-term basis and issue notes for the borrowing; and (B) issue bonds; and (4) obtain financing by other means permitted under Federal or State law. SEC. 5. ELIGIBILITY OF PASSENGER RAIL AS NATIONAL HIGHWAY SYSTEM PROJECT. Section 103(i) of title 23, United States Code, is amended by adding at the end the following: ``(14) Construction of and operational improvements for intercity passenger rail facilities, operation of intercity passenger rail trains, and acquisition of rolling stock for intercity passenger rail service, except that not more than 50 percent of the amount received by a State for a fiscal year under this paragraph may be obligated for operation.''. SEC. 6. ELIGIBILITY OF PASSENGER RAIL UNDER CONGESTION MITIGATION AND AIR QUALITY IMPROVEMENT PROGRAM. The first sentence of section 149(b) of title 23, United States Code, is amended-- (1) in paragraph (2), by striking ``or'' at the end; (2) in paragraph (3), by striking the period at the end and inserting ``; or''; and (3) by adding at the end the following: ``(4) if the project or program will have air quality benefits through construction of and operational improvements for intercity passenger rail facilities, operation of intercity passenger rail trains, and acquisition of rolling stock for intercity passenger rail service, except that not more than 50 percent of the amount received by a State for a fiscal year under this paragraph may be obligated for operating support.''. SEC. 7. ELIGIBILITY OF PASSENGER RAIL FOR MASS TRANSPORTATION FUNDING. (a) Definition of Mass Transportation.-- Section 5302(a)(7) of title 49, United States Code, is amended by inserting ``including intercity passenger rail transportation,'' after ``public''. (b) Definition of Designated Recipient.--Section 5307(a)(2) of title 49, United States Code, is amended-- (1) in subparagraph (B), by striking ``or'' at the end; (2) in subparagraph (C), by striking the period at the end and inserting ``; or'' and (3) by adding at the end the following: ``(D) a provider of intercity passenger rail transportation.''. (c) Financial Assistance for Other Than Urbanized Areas.--Section 5311(b) of title 49, United States Code, is amended by adding at the end the following: ``(3) Grants for intercity passenger rail service under this section shall be used to preserve the maximum choice of passenger modes in areas other than urbanized areas.''.

Intercity Rail Infrastructure Investment Act - Amends Federal highway system law to designate certain National Railroad Passenger Corporation (AMTRAK) intercity passenger rail service corridors to be part of the National Highway System. Grants congressional consent to States with an interest in a specific form, route, or corridor of intercity passenger rail service (including high speed rail service) to enter into interstate compacts to promote such service. Makes construction of and operational improvements for intercity passenger rail facilities, operation of intercity passenger rail trains, and acquisition of rolling stock for intercity passenger rail service eligible projects for funding under the National Highway System. Authorizes States to obligate congestion mitigation and air quality improvement program funds for such projects. Revises the term "mass transportation" to cover intercity passenger rail transportation. Makes such transportation projects eligible for Federal mass transportation funding. Requires grants for intercity passenger rail service to be used to preserve the maximum choice of passenger modes in non-urbanized areas.

the hubbard model is the standard model for strongly - correlated particles in a tight - binding lattice , and has been widely useful as a minimal model to describe a variety of transition metal oxides,@xcite quantum dot arrays@xcite and , more recently , trapped atomic gases.@xcite real materials are disordered and extensions of the hubbard model , most notably the anderson - hubbard model ( ahm ) , have been introduced to study the subtle interplay between disorder and interactions . like the hubbard model , the ahm has not been solved exactly , except in special cases , and appears to have a rich phase diagram . over the past decade , there has been considerable interest in anderson localization in strongly - correlated metals near half filling . at half filling , coulomb interactions can induce a gapped mott insulating " state , and the question is how states near the mott state are affected by strong interactions . this is particularly relevant to the cuprate high temperature superconductors , where the electronic properties are tuned by chemical doping . chemical doping , in addition to changing the carrier density ( and therefore proximity to the mott state ) , disorders the materials . experiments have generically found states exhibiting characteristics of anderson localization that lie between the metallic and mott insulating phases.@xcite the location of the metal insulator transition ( mit ) appears to be a function of both the itinerant hole density and the level of disorder , but not the residual ( @xmath0 ) resistivity,@xcite which hints at a possible failure of the conventional one - parameter scaling theory.@xcite more generally , these experiments raise the possibility that the anderson mit in strongly correlated materials may differ qualitatively from that in conventional weakly correlated metals . in this work , we use the ahm to study the effects of strong correlations on anderson localization . the anderson - hubbard hamiltonian is @xmath1 where the indices @xmath2 and @xmath3 refer to sites on a @xmath4-dimensional lattice , where @xmath5 annihilates a spin-@xmath6 electron from site @xmath2 , @xmath7 is the number operator for site @xmath2 , and where @xmath8 . we restrict ourselves to nearest - neighbor hopping , so that @xmath9 if @xmath2 and @xmath3 are nearest neighbors and @xmath10 otherwise . disorder is introduced via the site energies @xmath11 , which are chosen randomly from a uniform distribution of width @xmath12 ( so @xmath13 ) . the ahm is therefore characterized by three energy scales : the kinetic energy @xmath14 , the short range coulomb interaction @xmath15 , and the disorder strength @xmath12 . a rough schematic phase diagram for the half - filled ahm in three dimensions is shown in fig . [ fig : phasediag ] ( the phase diagram in lower dimensions has not , to our knowledge , been established ) . this phase diagram is based on a number of published calculations@xcite which , while they disagree on details , agree on general features . note that we have chosen to show the simplest nonmagnetic phase diagram ( in which magnetic phases are suppressed ) and have omitted phases that are not universally seen . there appears to be consensus on the strong disorder limit of the phase diagram : as a function of increasing @xmath15 , there is a continuous transition from a gapless anderson insulator to a gapped mott insulating state at @xmath16.@xcite an interesting , recently - discovered wrinkle in this picture is the existence of a kinetic energy - driven zero bias anomaly in the density of states,@xcite which was found in the one and two dimensional ahm and should presumably be present in higher dimensions . there is less consensus on the phase diagram at weak and intermediate disorder . some calculations have predicted that the density of states vanishes continuously at the mit in two@xcite and three@xcite dimensions while dynamical mean field theory@xcite ( dmft ) finds that the density of states is discontinuous across the mit , and variational monte carlo@xcite calculations predict a first order mott transition . although experiments are often complicated by the occurrence of broken - symmetry phases , paramagnetic mott transitions in real materials are generally found to be consistent with dmft.@xcite the details of the @xmath17 mit are important since they affect the electronic properties of the metal adjacent to the mott transition . to illustrate this point , we consider a simple weak - coupling expression for the screened random potential @xmath18 . within mean - field theory , @xmath19 , where @xmath20 is the spatially - averaged charge density and @xmath21 . for weak disorder , @xmath22 . a rough estimate for the charge susceptibility is @xmath23 , where @xmath24 is the single - spin density of states at the fermi energy . then @xmath25 in a weak - coupling metal , @xmath24 depends only weakly on @xmath15 and the overall effect of increasing @xmath15 is to screen the disorder potential . on the other hand , in a gapped insulator , @xmath26 and the impurity potential is unscreened . while eq . ( [ eq : vi ] ) applies to weakly - correlated insulators , we also expect screening to vanish in ( strongly - correlated ) mott insulators because the charge is unable to rearrange itself in response to the disorder potential . the screened potential should therefore be a nonmonotonic function of @xmath15 , obtaining a maximum value somewhere between small @xmath15 ( where eq . ( [ eq : vi ] ) holds ) and the critical value @xmath27 . indeed , several calculations have found that the impurity potential becomes unscreened as @xmath28 for strong disorder.@xcite on the other hand , dmft predicts that , for weak disorder , a narrow quasiparticle band develops at the fermi energy near @xmath29 , such that the density of states remains finite up to @xmath29 . it has been shown that because this band tends to be pinned to the fermi energy , impurity scattering within the band is reduced.@xcite in fact , for a particle - hole symmetric band , a weak impurity potential is predicted to be _ perfectly _ screened as @xmath28 . this remarkable result has , to our knowledge , only been found in dmft calculations and has not been confirmed by other theoretical techniques . in this work , we study persistent currents in an anderson - hubbard lattice threaded by an aharonov - bohm flux and focus on the region of strong correlations near the mott transition . these currents are affected by both the disorder potential ( which tends to localize the quasiparticles ) , and by strong correlations ( which reduce the quasiparticle spectral weight ) . one of the main objectives of our analysis is to separate these two competing effects , and we find the paradoxical result that the localization length may grow with increasing @xmath15 , even as the magnitude of the current is suppressed . in sec . [ sec : calculations ] , we describe how we calculate the persistent current for a ring or torus threaded by an aharonov - bohm flux . in sec . [ sec : results ] we compare clean and disordered systems with and without strong correlations , from which we develop a qualitative sense of the relative importance of disorder screening and strong correlations . we then show how these affect the localization length , which is extracted from the scaling of the persistent current with system size . we present results for two cases : quarter filling where correlations are relatively weak , and half filling where correlations are strongest . we find that , while the quarter - filling results are consistent with one - parameter scaling , there is evidence for a breakdown of one - parameter scaling at half - filling when the interaction strength @xmath15 is greater than the disorder strength @xmath12 . these results are discussed in sec . [ sec : conclusions ] . the hamiltonian is given by eq . ( [ eq : ham ] ) . an aharonov - bohm flux @xmath30 is introduced through a complex phase in the hopping matrix elements @xmath31 where @xmath32 , @xmath33 is the circumference of the ring ( in one dimension ) or torus ( in two dimensions ) , and @xmath34 is the electron displacement in the @xmath35 direction during the hop from site @xmath3 to site @xmath2 . the parameter @xmath36 is the magnitude of the aharonov - bohm flux in units of the flux quantum @xmath37 . the magnitude @xmath14 of the hopping matrix element between nearest - neighbor sites is taken to be the unit of energy throughout this work ( ie . @xmath38 ) . the variational ground state wavefunction has the gutzwiller form @xmath39 where @xmath40 is a slater product state wavefunction and @xmath41 $ ] is the gutzwiller projection operator . the parameter @xmath42 is a variational parameter that introduces correlations into the wavefunction ; the limit @xmath43 corresponds to a state with no double occupancies , while @xmath44 gives an uncorrelated wavefunction @xmath45 . this simple gutzwiller wavefunction can not , without additional jastrow factors , describe the mott transition;@xcite nonetheless , the gutzwiller projection is useful as a qualitative tool for understanding strong correlation physics near the mott transition . it is usual to take @xmath40 to be the many - body ground state of some effectively noninteracting hamiltonian , and we consider here two cases : ( i ) @xmath40 is the self - consistent paramagnetic hartree - fock ground state of @xmath46 , and ( ii ) @xmath40 is the ground state of a noninteracting hamiltonian with a screened disorder potential , @xmath47 the parameter @xmath48 is treated as a variational parameter , on the same footing as @xmath42 . we call the projected wavefunctions obtained from ( i ) and ( ii ) the paramagnetic gutzwiller wavefunction ( pmgw ) and the disordered filled sea gutzwiller wavefunction ( dfsgw ) respectively . while it is possible to include more variational parameters , for example by taking @xmath42 and @xmath48 to be site dependent,@xcite we found previously@xcite that it is sufficient to include spatial inhomogeneity only in @xmath40 when the disorder is not too strong ; it is only for strong disorder ( relative to the bandwidth ) that a spatially varying @xmath42 and @xmath48 are essential . this represents a large computational savings . and @xmath49 . results are at half filling , and are for a single configuration of disorder . the energy per electron _ inset : _ energy difference @xmath50 between the two variational states . ] the parameters @xmath42 and @xmath48 are determined by minimizing the energy functional @xmath51 for large systems , @xmath52 can not be evaluated exactly , and a variational monte carlo ( vmc ) method is used . the idea is to expand @xmath40 in terms of fock states @xmath53 ( states with a definite number of electrons on each site ) , such that @xmath54 . it is then simple to apply the gutzwiller projection : @xmath55 where @xmath56 , with @xmath57 the number of doubly occupied sites in the ket @xmath58 . then the variational energy can be written @xmath59 the double sum in the numerator is computationally prohibitive to calculate and , in the simplest approach , the sums over @xmath60 and @xmath61 are performed approximately using the metropolis algorithm with weighting factors @xmath62 and @xmath63 respectively . more sophisticated vmc algorithms exist , and in this work , we used the modified metropolis algorithm described in ref . . the results of the energy minimization are shown in fig . [ fig : energies ] , and suggest that there is little difference between the pmgw and dfsgw states . we shall see in the next section that although these two product states produce almost identical results for small @xmath33 , they make quantitatively different ( although qualitatively similar ) predictions for the persistent current when @xmath33 is large . this difference stems from how screening is handled : in the pmgw approximation , the self - consistent charge densities are obtained from a hartree - fock calculation _ before _ @xmath64 is minimized with respect to @xmath42 ; in the dfsgw approximation , @xmath52 is minimized with respect to the projection @xmath42 and screening @xmath48 simultaneously . we expect , therefore , that the pmgw state provides an upper bound on the screening , and where we have been able to compare with published results the dfsgw gives a more accurate estimate of the persistent current . , @xmath49 and @xmath65 . here and throughout this work , the aharanov - bohm flux is @xmath66 . results are shown for paramagnetic gutzwiller ( left ) and paramagnetic hartree fock ( right ) approximations . smooth curves are gaussian fits to the data for comparison . ] the aharonov - bohm flux in the hamiltonian generates a persistent current @xmath67 with @xmath68 we note that the persistent current is approximately related to the thouless conductance via @xmath69 . the persistent current depends on the length @xmath33 of the chain or torus , on the interaction strength , and on disorder . in the next section , much of the discussion involves a comparison of @xmath70 for systems with and without disorder . however , for one dimensional rings , it is also possible to perform a finite size scaling analysis from which the localization length can be extracted . for localized electrons , the persistent current satisfies @xmath71 in the limit @xmath72 , where @xmath73 is the localization length , and it is thus possible to extract the localization length from logarithmic plots of the persistent current as a function of system size . the current @xmath70 depends on the details of the disorder configuration and , in the noninteracting case , the distribution is log - normal when the system size is much larger than the localization length.@xcite examples of the distribution of the current values are given in fig . [ fig : currentdistribution ] . because of the approximate log - normal current distribution , we calculate the localization length from the _ typical _ value of the current @xmath74 where the bar denotes an average over disorder configurations . we begin by showing results for a single configuration of disorder as a function of @xmath15 . figures [ fig : j_vs_u2d ] and [ fig : j_vs_u ] show the persistent current at half filling as a function of the interaction strength in two and one dimensions respectively . the disorder strength is chosen to be equal to the bandwidth of the disorder - free lattice , namely @xmath75 in two dimensions and @xmath49 in one dimension . results are shown for both the pmgw and dfsgw ground states . in the two dimensional case , the two approximations produce nearly identical currents , while in one dimension they are quantitatively different , although qualitatively similar . the distinction appears to be that @xmath76 in fig . [ fig : j_vs_u2d ] while @xmath77 in fig . [ fig : j_vs_u ] ; in support of this , we have found that the dfsgw and pmgw currents in one dimension are nearly the same when @xmath33 is small ( inset of fig . [ fig : j_vs_u ] ) . for pmgw and dfsgw ground states for both a clean ( @xmath78 ) and disordered ( @xmath75 ) two dimensional plane . results are shown at half filling ( @xmath79 ) for a single disorder configuration with linear dimension @xmath80 . results with @xmath42 set to 1 by hand include screening but not strong correlations ; these are labelled pmhf ( paramagnetic hartree - fock , obtained from pmgw ) and dfs ( disordered fermi sea , obtained from dfsgw ) . the dfs curves have the same value of @xmath48 as the dfsgw curves . the inset shows the dependence of the variational parameters on @xmath15 . ] but for a one dimensional chain with @xmath81 and @xmath49 . the inset shows pmgw and dfsgw results for a short ( @xmath80 ) chain . ] the main point of figures [ fig : j_vs_u2d ] and [ fig : j_vs_u ] is that they allow us to distinguish the effects of screening and strong correlations on the persistent current . to separate these effects we show , in addition to @xmath82 and @xmath83 , results for calculations without disorder ( @xmath78 ) , without strong correlations , and with neither disorder nor strong correlations . to suppress strong correlations , the gutzwiller projection is explicitly turned off . these calculations are labelled paramagnetic hartree - fock " ( pmhf ) and disordered filled sea " ( dfs ) , and are obtained by setting @xmath44 in the pmgw and dfsgw calculations respectively . ( in the case of the dfs calculations , the screening @xmath48 is the same as in the corresponding dfsgw calculations . ) figures [ fig : j_vs_u2d ] and [ fig : j_vs_u ] show that , as @xmath15 increases , both @xmath84 and @xmath85 increase monotonically , and approach @xmath70 of the disorder - free system ( pmhf with @xmath78 ) . this indicates that , in the absence of strong correlations , disorder is progressively screened with increasing @xmath15 . in fig . [ fig : j_vs_u ] , the pmhf curves approach the disorder - free limit faster than the dfs curves , indicating that screening is stronger in the pmhf calculations ; however , the qualitative trends are the same in both cases . when the gutzwiller projections are included , the current is nearly identical to the unprojected current for small @xmath15 , and begins to differ from the unprojected current when @xmath86 . we have checked several different values of @xmath12 and found that this is generally the case : for intermediate disorder strengths , @xmath12 is the crossover scale beyond which strong correlations begin to play a significant role . when @xmath87 , the persistent current is progressively suppressed as @xmath15 increases . within the gutzwiller approximation , this suppression is interpreted in terms of a quasiparticle spectral weight that is reduced as the mott transition is approached . this mechanism is well - known and has been proposed , for example , to explain the anomalously low superfluid screening currents in underdoped cuprate superconductors.@xcite the most remarkable feature of figs . [ fig : j_vs_u2d ] and [ fig : j_vs_u ] is that , although the gutzwiller projected currents @xmath82 and @xmath83 are suppressed by strong correlations at large @xmath15 , they approach the value of the current in the ( strongly correlated ) disorder - free system . this indicates that , in spite of the strong correlations , the disorder potential continues to be screened by the interactions . we thus have the paradoxical result that the disorder screening _ increases _ with increasing @xmath15 , even though the overall current _ decreases_. in contrast , the usual expectation is that disorder screening should become worse as the mott transition is approached , as occurs for strong disorder . however , our result is consistent with earlier dmft estimates that suggest that the elastic scattering rate due to weak disorder vanishes at the mott transition.@xcite our result is also consistent with variational monte carlo calculations by pezzoli et al.,@xcite who used a similar variational approach to study the ahm . in particular , they introduced a variational renormalized site energy , similar to the parameter @xmath48 used here , and found a monotonic reduction of the effective disorder potential with increasing @xmath15 . we note that the gutzwiller calculations shown in figs . [ fig : j_vs_u2d ] and [ fig : j_vs_u ] break down above some critical interaction strength @xmath27 at which the mott mit occurs . where this happens depends on the level of disorder , and on the dimension of the lattice . for two dimensional clusters with @xmath75 , variational calculations@xcite find a first order mott transition at @xmath88 , which is well into the regime where both strong correlations and disorder screening are significant . for one dimensional systems , the mit happens at a smaller value ; we have performed exact diagonalization calculations for small clusters with @xmath49 that suggest that @xmath89 . it thus appears that the regime of strong screening and suppressed quasiparticle weight should be most easily observed in two and higher dimensions . ) . results are for clean ( @xmath78 ) and disordered ( @xmath90 ) systems for ( a ) a two dimensional lattice with @xmath80 and @xmath91 and ( b ) a one dimensional lattice with @xmath81 and @xmath92 . ] for comparison , we show results for the persistent current at quarter filling in fig . [ fig : quarter_filling ] . in this case , there is no mott transition to worry about , and the gutzwiller approximation is expected to be meaningful over a large range of @xmath15 values.@xcite the most striking feature of this figure is the diminished role of strong correlations at large @xmath15 , meaning that @xmath70 is not suppressed significantly at large @xmath15 . as with the half - filled case , the figure shows that the pmgw current approaches the disorder - free current in the large @xmath15 limit . the dfsgw current , on the other hand , is more weakly screened , and never approaches the clean limit value , but instead decays slowly from a maximum at @xmath93 with increasing @xmath15 . at quarter filling , then , the pmgw and dfsgw approximations are qualitatively different . in order to determine which result is correct , we have compared the two gutzwiller results with published exact diagonalization results for the drude weight at quarter filling in one dimension.@xcite we find that the @xmath15-dependence of the dfsgw current in fig . [ fig : quarter_filling](b ) is surprisingly close to the exact diagonalization results , and in the remainder of this work we therefore show only dfsgw results at quarter filling . in summary , figs . [ fig : j_vs_u2d ] and [ fig : j_vs_u ] illustrate one of the main results of this paper , namely that within the gutzwiller variational ansatz , strong correlations do not inhibit the screening of moderate disorder at half filling . as discussed above , we can extract the localization length @xmath73 from the finite size scaling of @xmath70 . in two dimensions @xmath73 tends to be exponentially large@xcite for weak disorder , and we can not reach the scaling limit @xmath94 . we therefore illustrate our point by looking at the one dimensional case , where it is possible to obtain @xmath95 , at least for @xmath15 not too large . we showed in the previous section that the qualitative roles of screening and correlations are the same in one and two dimensions , and we therefore expect that the main lessons learned about localization in one dimension will also apply to higher dimensions . to explore the full range of behavior , from weak to strong correlations , we include results for large @xmath15 where one dimensional systems are actually mott insulating , but which are accessible in higher dimensions . with system size in one dimension . typical currents are shown for half filling with ( a ) @xmath96 and ( b ) @xmath97 . data are for the pmgw approximation , solid lines are fits to the data from eq . ( [ eq : fit ] ) . data are calculated for @xmath98 disorder configurations , and error bars are give the statistical uncertainty in the typical current . where error bars are not shown , they are smaller than the symbol size . ( c ) the scaling function @xmath99 for pmgw at half filling ( left ) and dfsgw at quarter filling ( right ) . ] logarithmic plots of the typical current for pmgw calculations at half filling are shown in fig . [ fig : scaling ] . lines are fits to the data of the form @xmath100 where @xmath101 , @xmath73 , @xmath102 , and @xmath103 are fitting parameters . the last term is a finite size correction , meant to account for leading order corrections when @xmath33 is of order @xmath73 . clearly , the form of the correction can not hold for small @xmath33 , but it improves the quality of the fit significantly over the range of system sizes studied here . two distinct trends can be seen in fig . [ fig : scaling ] : for @xmath96 , the magnitude of @xmath104 increases with @xmath15 , but the slope decreases ; for @xmath87 , the magnitude of @xmath104 decreases with increasing @xmath15 , and the slope continues to decrease . since the slope is the inverse of the localization length , a decreasing slope corresponds to an increasing localization length . the localization length is shown in fig . [ fig : localizationlength ] . at half filling , the pmgw and dfsgw results are qualitatively consistent ; in both cases , the localization length grows monotonically with @xmath15 . ( note that where @xmath73 exceeds the largest system sizes , namely @xmath105 , the scaling ansatz eq . ( [ eq : fit ] ) ceases to give quantitatively accurate values for @xmath73 , and the results are qualitative only . ) there is thus a region of the phase diagram where the overall magnitude of the current is suppressed by strong correlations , but the localization length grows with @xmath15 . in contrast , at quarter filling , the localization length saturates at large @xmath15 . in fig . [ fig : scaling](c ) , we plot the scaling function @xmath106 as a function of @xmath107 for both half filling and quarter filling . note that the derivative in eq . ( [ eq : scaling ] ) is obtained from the fitted curves in figs . [ fig : scaling ] ( a ) and ( b ) . when one - parameter scaling holds , @xmath99 is a single - valued function of @xmath104 . the main branch of the data shown in fig . [ fig : scaling](c ) corresponds to @xmath108 and is , within the accuracy of our data , a function of @xmath104 alone . there is also a small hook - shaped feature in the upper right hand corner of the figure that corresponds to a second branch which comes from @xmath109 . this branch bends back towards the left , making @xmath99 a multi - valued function of @xmath104 . at half filling , it appears that one parameter scaling breaks down when @xmath109 . in contrast , the quarter - filling data lies entirely on the main branch , and therefore appears to satisfy one - parameter scaling . this breakdown of one parameter scaling at half filling follows directly from the two competing tendencies illustrated in figs . [ fig : j_vs_u2d ] and [ fig : j_vs_u ] . the main branch of the @xmath99 function comes from @xmath108 , where @xmath70 depends on @xmath15 primarily through disorder screening , while the second branch comes from @xmath109 where strong correlations are significant . while this breakdown may be hard to observe in one dimension because of the relatively low value of @xmath29 , it should be observable in two and higher dimensions . for ( a ) pmgw and dfsgw at half - filling and ( b ) dfsgw at quarter - filling . pmhf results are shown for comparison . ] we note that our dfsgw results for @xmath73 at quarter filling are entirely consistent with published dmrg calculations by nishimoto et al.@xcite it is difficult to compare results at half - filling , however , because the authors perform their dmrg calculations for @xmath110 , and calculate @xmath73 as a function of filling , while enhanced disorder screening is predicted to occur at half - filling as @xmath28 . in summary , we have studied the effects of disorder and strong correlations on transport in the anderson hubbard model . we have focused on the interaction - driven mott transition at half filling with weak and intermediate strength disorder . we used a gutzwiller variational ansatz to describe the strongly correlated state near the mott transition , and studied persistent currents induced by an aharonov - bohm flux . we found that the persistent current is a nonmonotonic function of @xmath15 . for small @xmath15 , the coulomb interactions screen the disorder potential and the current is an increasing function of @xmath15 . for large @xmath15 , strong correlations suppress the current , which becomes a decreasing function of @xmath15 . the crossover between these two limits occurs at @xmath86 . the main surprise in our calculations is that disorder screening persists when @xmath15 is large . one consequence of this is that in the strongly correlated regime ( @xmath109 ) the localization length is an increasing function of @xmath15 , even though the current itself is a decreasing function of @xmath15 . we expect that this apparently - paradoxical behavior should be observable two and higher dimensions . rjg and waa acknowledge nserc of canada for their support . this work was made possible by the facilities of the shared hierarchical academic research computing network ( sharcnet : www.sharcnet.ca ) and compute / calcul canada .

we have studied the effects of interactions on persistent currents in half - filled and quarter - filled hubbard models with weak and intermediate strength disorder . calculations are performed using a variational gutzwiller ansatz that describes short range correlations near the mott transition . we apply an aharonov - bohm magnetic flux , which generates a persistent current that can be related to the thouless conductance . the magnitude of the current depends on both the strength of the screened disorder potential and the strength of electron - electron correlations , and the anderson localization length can be extracted from the scaling of the current with system size . at half filling , the persistent current is reduced by strong correlations when the interaction strength is large . surprisingly , we find that the disorder potential is strongly screened in the large interaction limit , so that the localization length grows with increasing interaction strength even as the magnitude of the current is suppressed . this supports earlier dynamical mean field theory predictions that the elastic scattering rate is suppressed near the mott transition .

search for the quark - gluon plasma ( qgp ) at relativistic heavy - ion collision experiments ( rhice ) has reached a very exciting stage with the ongoing experiments at rhic and with the upcoming heavy - ion experiments at the large hadron collider . no one doubts that the qgp phase has already been created at rhic but conclusive evidence for the same is still lacking . many signatures have been proposed for the detection of the qgp phase @xcite and these have been thoroughly investigated both theoretically and experimentally . along with continued investigation of these important signatures of qgp , there is a need for investigating novel signals exploring qualitatively non - trivial features of the qgp phase and/or the quark - hadron phase transition . with this view we focus on the non - trivial vacuum structure of the qgp phase which arises when one uses the expectation value of the polyakov loop @xmath1 as the order parameter for the confinement - deconfinement phase transition @xcite . this order parameter transforms non - trivially under the center @xmath0 of the color su(3 ) group and is non - zero above the critical temperature @xmath2 . this breaks the global @xmath0 symmetry spontaneously above @xmath2 , while the symmetry is restored below @xmath2 in the confining phase where this order parameter vanishes . in the qgp phase , due to spontaneous breaking of the discrete @xmath0 symmetry , one gets domain walls ( interfaces ) which interpolate between different @xmath0 vacua . the properties and physical consequences of these @xmath0 interfaces have been discussed in the literature@xcite . it has been suggested that these interfaces should not be taken as physical objects in the minkowski space @xcite . similarly , it has also been subject of discussion whether it makes sense to talk about this @xmath0 symmetry in the presence of quarks @xcite . however , we will follow the approach where the presence of quarks is interpreted as leading to explicit breaking of @xmath0 symmetry , lifting the degeneracy of different @xmath0 vacua @xcite . thus , with quarks , even planar @xmath0 interfaces do not remain static and move away from the region with the unique true vacuum . our main discussion will be for the pure gauge theory which we discuss first . later we will briefly comment on the situation with quarks . a detailed study with inclusion of quark effects is postponed for a future work . in earlier works some of us had shown that there are novel topological string defects which form at the intersection of the three @xmath0 interfaces . these strings are embedded in the qgp phase and their cores consist of the confining phase . structure of these strings and interfaces were discussed in these earlier works @xcite . it was also shown that reflection of quarks from collapsing @xmath0 interfaces can lead to large scale baryon inhomogeneities in the early universe @xcite . this effect is also utilized to argue for @xmath3 enhancement of quarks of heavy flavor ( consecutively corresponding hadrons ) in relativistic heavy - ion collisions @xcite . in this paper we carry out numerical simulation of formation of these @xmath0 interfaces and associated strings at the initial confinement - deconfinement transition which is believed to occur during the pre - equilibrium stage in relativistic heavy - ion collision experiments . for the purpose of numerical simulation we will model this stage as a quasi - equilibrium stage with an effective temperature which first rises ( with rapid particle production ) to a maximum temperature @xmath4 , where @xmath2 is the critical temperature for the confinement - deconfinement phase transition , and then decreases due to continued plasma expansion . we use the effective potential for the polyakov loop expectation value @xmath1 as proposed by pisarski @xcite to study the confinement - deconfinement ( c - d ) phase transition . within this model , the c - d transition is weakly first order . even though lattice results show that quark - hadron transition is most likely a smooth cross - over at zero chemical potential , in the present work we will use this first order transition model to discuss the dynamical details of quark - hadron transition . one reason for this is that our study is in the context of relativistic heavy - ion collision experiments ( rhice ) where the baryon chemical potential is not zero . for not too small values of the chemical potential , the quark - hadron phase transition is expected to be of first order , so this may be the case relevant for us any way ( especially when collision energy is not too high ) . further , our main interest is in determining the structure of the network of z(3 ) domain walls and strings resulting during the phase transition . these objects will form irrespective of the nature of the transition , resulting entirely from the finite correlation lengths in a fast evolving system , as shown by kibble @xcite . the kibble mechanism was first proposed for the formation of topological defects in the context of the early universe @xcite , but is now utilized extensively for discussing topological defects production in a wide variety of systems from condensed matter physics to cosmology @xcite . essential ingredient of the kibble mechanism is the existence of uncorrelated domains of the order parameter which result after every phase transition occurring in finite time due to finite correlation length . a first order transition allows easy implementation of the resulting domain structure especially when the transition proceeds via bubble nucleation . with this view , we use the polyakov loop model as in @xcite to model the phase transition and confine ourselves with temperature / time ranges so that the first order quark - hadron transition proceeds via bubble nucleation . the @xmath0 wall network and associated strings ( as mentioned above ) formed during this early confinement - deconfinement phase transition evolve in an expanding plasma with decreasing temperature . eventually when the temperature drops below the deconfinement - confinement phase transition temperature @xmath2 , these @xmath0 walls and associated strings will melt away . however they may leave their signatures in the form of extended regions of energy density fluctuations ( as well as @xmath3 enhancement of heavy - flavor hadrons @xcite ) . we make estimates of these energy density fluctuations which can be compared with the experimental data . especially interesting will be to look for extended regions of large energy densities in space - time reconstruction of hadron density ( using hydrodynamic models ) . in our model , we expect energy density fluctuations in event averages ( representing high energy density regions of domain walls / strings ) , as well as event - by - event fluctuations as the number / geometry of domain walls / strings and even the number of qgp bubbles , varies from one event to the other . a detailed analysis of energy fluctuations , especially the event - by - event fluctuations , is postponed for a future work . we also determine the distribution / shape of @xmath0 wall network and its evolution . in particular , our results provide an estimate of domain wall velocities ( for the situations studied ) to range from 0.5 to 0.8 . these results provide crucial ingredients for a detailed study of the effects of collapsing @xmath0 walls on the @xmath3 enhancement of heavy flavor hadrons @xcite in rhice . we emphasize that the presence of @xmath0 walls and string may not only provide a qualitatively new signature for the qgp phase in these experiments , it may provide the first ( and may be the only possible ) laboratory study of such topological objects in a relativistic quantum field theory system . the paper is organized in the following manner . in section ii , we discuss the polyakov loop model of confinement - deconfinement phase transition . we describe the effective potential proposed by pisarski @xcite and discuss the structure of the @xmath0 walls and associated strings . in section iii , we present the physical picture of the formation of these @xmath0 walls and associated strings in the confinement - deconfinement phase transition via the kibble mechanism which provides a general framework for the production of topological defects in symmetry breaking phase transitions . we confine ourselves with temperature / time ranges so that the first order transition ( in the pisarski model ) proceeds via bubble nucleation . the other possibility of spinodal decomposition is of completely different nature and we will present it in a future work . ( we mention here that a simulation of spinodal decomposition in polyakov loop model has been carried out in ref . @xcite , where fluctuations in the polyakov loop are investigated in detail . in comparison , the main focus of our work is on the topological objects , z(3 ) walls , and strings , and energy density fluctuations resulting therefrom . ) in section iv , we discuss the calculation of the profile of the critical bubble using bounce technique @xcite and also the estimates of nucleation rates for bubbles for the temperature / time range relevant for rhice . section v presents the numerical technique of simulating the phase transition via random nucleation of bubbles . in section vi we discuss the issue of the effects of quarks in our model . section vii presents the results of the numerical simulations . here we discuss distribution of @xmath0 wall / string network formed due to coalescence of qgp bubbles ( in a confining background ) . we also calculate the energy density fluctuations associated with @xmath0 wall network and strings . we discuss evolution of these quantities with changing temperature via bjorken s hydrodynamical model . in section viii we discuss possible experimental signatures resulting from the presence of @xmath0 wall network and associate strings . section ix presents conclusions . we first discuss the case of pure su(n ) gauge theory . we will later discuss briefly the case with quarks . the order parameter for the confinement - deconfinement ( c - d ) phase transition is the expectation value of the polyakov loop @xmath5 which is defined as @xmath6 here p denotes the path ordering , g is the gauge coupling , and @xmath7 , where t is the temperature . @xmath8 , @xmath9 being the generators of su(n ) in the fundamental representation , is the time component of the vector potential at spatial position @xmath10 and euclidean time @xmath11 . under a global z(n ) symmetry transformation , @xmath5 transforms as @xmath12 the expectation value of @xmath1 is related to @xmath13 where @xmath14 is the free energy of an infinitely heavy test quark . for temperatures below @xmath2 , in the confined phase , the expectation value of polyakov loop is zero corresponding to the infinite free energy of an isolated test quark . ( hereafter , we will use the same notation @xmath1 to denote the expectation value of the polyakov loop . ) hence the z(n ) symmetry is restored below @xmath2 . z(n ) symmetry is broken spontaneously above @xmath2 where @xmath1 is non - zero corresponding to the finite free energy of the test quark . for qcd , @xmath15 , and we take the effective theory for the polyakov loop as proposed by pisarski @xcite . the effective lagrangian density is given by @xmath16 @xmath17 is the effective potential for the polyakov loop @xmath18 the values of various parameters are fixed to reproduce the lattice results @xcite for pressure and energy density of pure su(3 ) gauge theory . we make the same choice and give those values below . the coefficients @xmath19 and @xmath20 have been taken as , @xmath21 and @xmath22 . we will take the same value of @xmath23 for real qcd ( with three massless quark flavors ) , while the value of @xmath20 will be rescaled by a factor of 47.5/16 to account for the extra degrees of freedom relative to the degrees of freedom of pure su(3 ) gauge theory @xcite . the coefficient @xmath23 is temperature dependent @xcite . @xmath23 is taken as , @xmath24 , where r is taken as t/@xmath2 . with the coefficients chosen as above , the expectation value of order parameter approaches to @xmath25 for temperature @xmath26 . as in @xcite , we use the normalization such that the expectation value of order parameter @xmath27 goes to unity for temperature @xmath26 . hence the fields and the coefficients in @xmath28 are rescaled as @xmath29 , @xmath30 , @xmath31 and @xmath32 to get proper normalization of @xmath27 . for the parameters chosen as above , the value of @xmath2 is taken to be 182 mev . we see that the @xmath19 term in eq.(4 ) gives a cos(3@xmath33 ) term , leading to z(3 ) degenerate vacua structure . here , the shape of the potential is such that there exists a metastable vacuum upto a temperature @xmath34 250 mev . hence first order transition via bubble nucleation is possible only upto @xmath35 mev . we show the plot of v@xmath36 in @xmath37 direction in fig.(1a ) for a value of temperature t = 185 mev . this shows the metastable vacuum at @xmath38 . fig.(1b ) shows the structure of vacuum by plotting v(@xmath39 ) as a function of @xmath33 for fixed @xmath27 , where @xmath40 is the vacuum expectation value of @xmath17 at @xmath41 mev . + \(a ) plot of @xmath28 in @xmath42 direction for @xmath43 showing the metastable vacuum at @xmath44 . in ( a ) and ( b ) , plots of @xmath45 are given in units of @xmath46 . the value of critical temperature is taken to be @xmath47 . the @xmath0 structure of the vacuum can be seen in ( b ) in the plot of the potential @xmath28 as a function of @xmath33 for fixed @xmath48 . here , @xmath40 corresponds to the absolute minimum of @xmath28 . [ fig.1 ] in fig.(1b ) , the three degenerate vacua are separated by large barrier in between them . while going from one vacuum to another vacuum , the field configuration is determined from the field equations . for the case of degenerate vacua , there are time independent solutions which have planar symmetry . these solutions are called domain wall . for the non - degenerate case , as will be appropriate for the case when quarks are included as dynamical degrees of freedom in discussing the quark hadron transition , the solutions of the interfaces separating these vacua will be similar to the bounce solutions @xcite , though the standard bounce techniques need to be extended for the case of complex scalar field . the resulting planar domain wall solutions will not be static . as mentioned above , we will be neglecting such effects of quarks , and hence will discuss the case of degenerate vacua only . later , in section vi , we will examine the justification of using the approximation of neglecting quark effects . in physical space , after the phase transition , regions with different z(3 ) vacua are separated by domain walls . inside a domain wall , @xmath49 becomes very small as @xmath50 @xcite . in ref.@xcite the intersection of the three z(3 ) domain walls was considered and , using topological arguments , it was then shown that at the line - like intersection of these interfaces , the order parameter @xmath1 should vanish . this leads to a topological string configuration with core of the string being in the confining phase . properties of these new string configurations were determined in @xcite using the model of eq.(3 ) . this string configuration is interesting , especially when we note that such a string has exactly reverse physical behavior compared to the standard qcd string . the qcd string exists in the confining phase , connecting quarks and antiquarks , or forming baryons , glueballs etc . inside the qcd string , the core region is expected to behave as a deconfined region . in contrast the string discussed in @xcite , arising at the intersection of z(3 ) walls , exists in the high temperature deconfined phase . its core is characterized by restored @xmath0 symmetry , implying that it is in the confined phase . to differentiate it with the standard qcd string , this new string structure was called as _ the qgp string _ in ref.@xcite . it is also important to note that although the standard qcd string breaks by creating quark - antiquark pairs , the qgp string can not break as it originates from topological arguments . this qgp string , thus should either form closed loops , or it should end at the boundary separating the deconfined phase from the confined phase . its structure is very similar to certain axionic strings discussed in the context of early universe @xcite . note that as these strings contain the confining phase ( with @xmath44 ) in the core , while they are embedded in the qgp phase , a transition from deconfining phase to the confining phase , in the presence of such strings may begin from regions near the strings . similarly , the presence of domain walls may lead to heterogeneous bubble nucleation in a first order quark - hadron transition . we will be studying the formation of z(3 ) domain walls and these qgp strings in the initial confinement - deconfinement phase transition , and their subsequent evolution . we now briefly describe the physical picture of the formation of topological defects via the kibble mechanism . kibble first gave a detailed theory of the formation of topological defects in symmetry breaking phase transitions in the context of the early universe @xcite . subsequently it was realized that the basic physics of kibble mechanism is applicable to every symmetry breaking transition , from low energy physics of condensed matter systems to high energy physics relevant for the early universe @xcite . basic physics of the kibble mechanism can be described as follows . after a spontaneous symmetry breaking phase transition , the physical space consists of regions , called domains . in each domain the configuration of the order parameter field can be taken as nearly uniform while it varies randomly from one domain to another . in a numerical simulation where the phase transition is modeled to implement the kibble mechanism , typically the physical region is divided in terms of elementary domains of definite geometrical shape . the order parameter is taken to be uniform within the domain and random variations of order parameter field within the vacuum manifold are allowed from one domain to the other . the order parameter field configuration in between domains is assumed to be such that the variation of the order parameter field is minimum on the vacuum manifold ( the so - called geodesic rule ) . with this simple construction , topological defects arise at the junctions of several domains if the variation of the order parameter in those domains traces a topologically non - trivial configuration in the vacuum manifold . see , ref . @xcite for a detailed discussion of this approach . we , however , will follow a more detailed simulation as in ref.@xcite where the kibble mechanism was implemented in the context of a first order transition . bubbles of true vacuum ( determined from the bounce solution ) were randomly nucleated in the background of false vacuum . each bubble was taken to have the uniform orientation of the order parameter in the vacuum manifold , while the order parameter orientation varied randomly from one bubble to another . this provided the initial seed domains , as needed for the kibble mechanism . evolution of this initial configuration via the field equation led to expansion of bubbles which eventually coalesce and lead to the formation of topological defects at the junctions of bubbles when the order parameter develops appropriate variation ( winding ) in that region . important thing is that in this case one does not need to assume anything like the geodesic rule . as different bubbles come into contact during their expansion , the value of the order parameter in the intermediate region is automatically determined by the field equations . an important aspect of the kibble mechanism is that it does not crucially depend on the dynamical details of the phase transition . although the domain size depends on the dynamics of phase transitions , the defect number density ( per domain ) and type of topological defects produced via the kibble mechanism depends only on the topology of order parameter space and spatial dimensions . if the vacuum manifold m has disconnected components , then domain walls form . if it is multiply connected ( i.e. , if m contains unshrinkable loops ) , strings will form . when m contains closed two surfaces which can not be shrunk to a point , then monopoles will form in three dimensional physical space . in our case domain walls and string network will be produced in the qgp phase . as discussed above , domain walls arise due to interpolation of field between different z(3 ) vacua . at the intersection of these interfaces , string is produced . as we explained in the introduction , we will study the z(3 ) domain wall and string formation with the first order transition model given by eq.(3 ) , such that the transition occurs via bubble nucleation . the semiclassical theory of decay of false vacuum at zero temperature has been given in ref . @xcite , and the finite temperature extension of this theory was given in ref . the process of barrier tunneling leads to the appearance of bubbles of the new phase . resulting bubble profile is determined using the bounce solution for the false vacuum decay which we will discuss below . first we note general features of the dynamics of a standard first order phase transition at finite temperature via bubble nucleation . a region of true vacuum , in the form of a spherical bubble , appears in the background of false vacuum . the creation of bubble leads to the change in the free energy of the system as , @xmath51 where r is the radius of bubble , @xmath52 is the surface energy contribution and @xmath53 is the volume energy contribution . @xmath54 is the difference of the free energy between the false vacuum and the true vacuum and @xmath55 is the surface tension which can be determined from the bounce solution . a bubble of size @xmath56 will expand or shrink depending on which process leads to lowering of the free energy given above . the bubbles of very small sizes will shrink to nothing since surface energy dominates . if the radius of bubble exceeds the critical size @xmath57 , it will expand and lead to the transformation of the metastable phase into the stable phase . eq.(5 ) is useful for the so - called _ thin wall _ bubbles where there is a clear distinction between the surface contribution to the free energy and the volume contribution . for the temperature / time relevant for our case in relativistic heavy - ion collisions this will not be the case . instead we will be dealing with the _ thick wall _ bubbles where surface and volume contributions do not have clear separations . we will determine the profiles of these thick wall bubbles numerically following the bounce technique @xcite . first we note that for the effective potential in eq.(4 ) , the barrier between true vacuum and false vacuum vanishes at temperatures above about 250 mev . so first order transition via bubble nucleation is possible only within the temperature range of @xmath58 mev - 250 mev . above @xmath59 250 mev , spinodal decomposition will take place due to the roll down of field . implementation of the dynamics of phase transition via spinodal decomposition is of completely different nature , and we hope to discuss this in a future work . as we are discussing the initial confinement - deconfinement transition in the context of rhice , clearly the discussion has to be within the context of longitudinal expansion only , with negligible effects of the transverse expansion . however , bjorken s longitudinal scaling model @xcite can not be applied during this pre - equilibrium phase , even with the assumption of quasi - equilibrium ( as discussed above ) , unless one includes a heat source which could account for the increase of effective temperature during this phase to the maximum equilibrium temperature @xmath60 . as indicated above , this heat source can be thought of as representing the rapid particle production ( with subsequent thermalization ) during this early phase . we will not attempt to model such a source here . instead , we will simply use the field equations resulting from bjorken s longitudinal scaling model for the evolution of the field configuration for the entire simulation , including the initial pre - equilibrium phase from @xmath61 to @xmath62 . the heating of the system until @xmath63 will be represented by the increase of the temperature upto @xmath64 . thus , during this period , the energy density and temperature evolution will not obey the bjorken scaling equations @xcite . after @xmath65 , with complete equilibrium of the system , the temperature will decrease according to the equations in the bjorken s longitudinal scaling model . we will take the longitudinal expansion to only represent the fact that whatever bubbles will be nucleated , they get stretched into ellipsoidal , and eventually cylindrical , shapes during the longitudinal expansion ( ignoring the boundary effects in the longitudinal direction ) . the transverse expansion of the bubble should then proceed according to relative pressure difference between the false vacuum and the true vacuum as in the usual theory of first order phase transition . we will neglect transverse expansion for the system , and focus on the mid rapidity region . with this picture in mind , we will work with effective 2 + 1 dimensional evolution of the field configuration , ( neglecting the transverse expansion of qgp ) . however , for determining the bubble profile and the nucleation probability of bubbles , one must consider full 3 + 1 dimensional case as bubbles are nucleated with full 3-dimensional profiles in the physical space . it will turn out that the bubbles will have sizes of about 1 - 1.5 fm radius . taking the initial collision region during the pre - equilibrium phase also to be of the order of 1 - 2 fm in the longitudinal direction , it looks plausible that the nucleation of 3-dimensional bubble profile as discussed above may provide a good approximation . of course the correct thing will be to consider the bounce solutions for rapidly longitudinally expanding plasma , and we hope to return to this issue in some future work . we neglect transverse expansion in the present work , which is a good approximation for the early stages when wall / string network forms . however , this will not be a valid approximation for later stages , especially when temperature drops below @xmath2 and wall / string network melts . the way to account for the transverse expansion in the context of our simulation will be to take a lattice with much larger physical size than the initial qgp system size , and allow free boundary conditions for the field evolution at the qgp system boundary ( which will still be deep inside the whole lattice ) . this will allow the freedom for the system to expand in the transverse direction automatically . with a suitable prescription of determining temperature from local energy density ( with appropriate account of field contributions and expected contribution from a plasma of quarks and gluons ) in a self consistent manner , the transverse expansion can be accounted for in this simulation . we hope to come back to this in a future work . let us consider the effective potential in eq.(4 ) , at a temperature such that there is a barrier between the true vacuum and the three z(3 ) vacua . an example of this situation is shown in fig.1 for the case with @xmath66 185 mev . the initial system ( of nucleons ) was at zero temperature with the order parameter l(x ) = 0 , and will be superheated as the temperature rises above the critical temperature . it can then tunnel through the barrier to the true vacuum , representing the deconfined qgp phase . at zero temperature , the tunneling probability can be calculated by finding the bounce solution which is a solution of the 4-dimensional euclidean equations of motion however , at finite temperature , this 4-dimensional theory will reduce to an effectively 3 euclidean dimensional theory if the temperature is sufficiently high , which we will take to be the case . for this finite temperature case , the tunneling probability per unit volume per unit time in the high temperature approximation is given by @xcite ( in natural units ) @xmath67 where @xmath68 is the 3-dimensional euclidean action for the polyakov loop field configuration that satisfies the classical euclidean equations of motion . the condition for the high temperature approximation to be valid is that @xmath69 , where @xmath70 is the radius of the critical bubble in 3 dimensional euclidean space . the values of temperature for our case ( relevant for bubble nucleation ) will be above @xmath71 mev . as we will see , the bubble radius will be larger than 1.5 fm ( @xmath34 ( 130 mev)@xmath72 ) which justifies our use of high temperature approximation to some extent . the determination of the pre - exponential factor is a non - trivial issue and we will discuss it below . the dominant contribution to the exponential term in @xmath73 comes from the least action @xmath74 symmetric configuration which is a solution of the following equation ( for the lagrangian in eq.(3 ) ) . @xmath75 where @xmath76 , subscript e denoting the coordinates in the euclidean space . the boundary conditions imposed on @xmath77 are @xmath78 bounce solution of eq.(7 ) can be analytically obtained in the _ thin wall _ limit where the difference in the false vacuum and the true vacuum energy is much smaller than the barrier height . this situation will occur for very short time duration near @xmath79 for the effective potential in eq.(4 ) . however , as the temperature is rapidly evolving in the case of rhice , there will not be enough time for nucleating such large bubbles ( which also have very low nucleation rates due to having large action ) . thus the case relevant for us is that of thick wall bubbles whose profile has to be obtained by numerically solving eq.(7 ) . as we have mentioned earlier , in the high temperature approximation the theory effectively becomes 3 ( euclidean ) dimensional . for a theory with one real scalar field in three euclidean dimensions the pre - exponential factor arising in the nucleation rate of critical bubbles has been estimated , see ref . the pre - exponential factor obtained from @xcite for our case becomes @xmath80 it is important to note here that the results of @xcite were for a single real scalar field and one of the crucial ingredients used in @xcite for calculating the pre - exponential factor was the fact that for a bounce solution the only light modes contributing to the determinant of fluctuations were the deformations of the bubble perimeter . even though we are discussing the case of a complex scalar field @xmath1 , this assumption may still hold as we are calculating the tunneling from the false vacuum to one of the z(3 ) vacua ( which are taken to be degenerate here as we discussed above ) . this assumption may need to be revised when light modes e.g. goldstone bosons are present which then also have to be accounted for in the calculation of the determinant . a somewhat different approach for the pre - exponential factor in eq.(6 ) is obtained from the nucleation rate of bubbles per unit volume for a liquid - gas phase transition as given in ref . @xcite , @xmath81 here @xmath82 is the dynamical prefactor which determines the exponential growth rate of critical droplets . @xmath83 is a statistical prefactor which measures the available phase space volume . the exponential term is the same as in eq.(6 ) with @xmath84 being the change in the free energy of the system due to the formation of critical droplet . this is the same as @xmath85 in eq.(6 ) . the bubble grows beyond the critical size when the latent heat is conducted away from the surface into the surrounding medium which is governed by thermal dissipation and viscous damping . for our case , in the general framework of transition from a hadronic system to the qgp phase , we will use the expression for the dynamical prefactor from ref.@xcite @xmath86 here @xmath55 is the surface tension of the bubble wall , @xmath87 is the difference in the enthalpy densities of the qgp and the hadronic phases , @xmath88 is thermal conductivity , @xmath89 is the critical bubble radius , and @xmath54 and @xmath90 are shear and bulk viscosities . @xmath90 will be neglected as it is much smaller than @xmath54 . for @xmath88 and @xmath54 , the following parametrizations are used @xcite . @xmath91 @xmath92 here @xmath93 is the ratio of the baryon density of the system to the normal nuclear baryon density , @xmath94 is in mev , @xmath54 is in mev/@xmath95c , and @xmath88 is in c/@xmath95 . with this , the rate in eq.(10 ) is in @xmath96 . for the range of temperatures of our interest ( @xmath97 ) , and for the low baryon density central rapidity region under consideration , it is the last @xmath98 independent term for both @xmath54 and @xmath82 which dominates , and we will use these terms only for calculating @xmath54 and @xmath82 for our case . for the statistical prefactor , we use the following expression @xcite @xmath99 the correlation length in the hadronic phase , @xmath100 , is expected to be of order of 1 fm and we will take it to be 0.7 fm @xcite ) . we will present estimates of the nucleation rates from eq.(6 ) as well as eq.(10 ) . one needs to determine the critical bubble profile and its 3-dimensional euclidean action @xmath85 ( equivalently , @xmath84 in eq.(10 ) ) . we solve eq.(7 ) using the fourth order runge - kutta method with appropriate boundary conditions ( eq.(8 ) ) , to get the profile of critical bubble @xcite . the critical bubble profiles ( for the 3 + 1 dimensional case ) are shown in fig.(2a ) for different temperatures . the bubble size decreases as temperature increases , since the energy difference between true vacuum and false vacuum increases ( relative to the barrier height ) as temperature increases . we choose a definite temperature @xmath101 mev for the nucleation of bubbles , which is suitably away from @xmath2 to give acceptable bubble size and nucleation probabilities for the relevant time scale . making @xmath94 larger ( up to @xmath102 mev when the barrier disappears ) leads to similar bubble profile , and the nucleation probability of same order . + \(a ) critical bubble profiles for different values of the temperature . ( b ) solid curve shows the critical bubble for the 3 + 1 dimensional case ( which for finite temperature case becomes 3 euclidean dimensional ) for @xmath94 = 200 mev and the dotted curve shows the same for 2 + 1 dimensional case ( i.e. 2 euclidean dimensions for finite temperature case ) . [ fig.2 ] recall that we are calculating bubble profiles using eq.(7 ) relevant for the 3 + 1 dimensional case , however , the field evolution is done using 2 + 1 dimensional equations as appropriate for the mid rapidity region of rapidly longitudinally expanding plasma . in fig.(2b ) solid curve shows the critical bubble for the 3 + 1 dimensional case ( which for finite temperature case becomes 3 euclidean dimensional ) for @xmath94 = 200 mev and the dashed curve shows the same for 2 + 1 dimensional case ( i.e. 2 euclidean dimensions for finite temperature case ) . it is clear that the 3 dimensional bubble is of supercritical size and will expand when evolved with 2 + 1 dimensional equations . this avoids the artificial construction of suitable supercritical bubbles which can expand and coalesce as was done in ref.@xcite . ( recall that for the finite temperature case , a bubble of exact critical size will remain static when evolved by the field equations . in a phase transition , bubbles with somewhat larger size than the critical size expand , while those with smaller size contract . ) for the bubble profile given by the solid curve in fig.(2b ) , the value of the action @xmath68 is about 240 mev . using eq.(6 ) for the nucleation rate , we find that the nucleation rate of qgp bubbles per unit time per unit volume is of the order of @xmath103 . the thermalization time for qgp phase is of the order of 1 fm at rhic ( say , for au - au collision at 200 gev energy ) . hence the time available for the nucleation of qgp bubbles is at most about 1 fm . we take the region of bubble nucleation to be of thick disk shape with the radius of the disk ( in the transverse direction ) of about 8 fm and the thickness of the disk ( in the longitudinal direction ) of about 1 fm . total space - time volume available for bubble nucleation is then about 200 @xmath104 ( in practice , less than this ) . for the case of eq.(6 ) , net number of bubbles is then equal to 5 . for the case of the nucleation rate given by eq.(10 ) , one needs an estimate of the critical bubble size @xmath89 as well as bubble surface energy @xmath55 , ( along with other quantities like @xmath88 etc . as given by eqs.(11)-(14 ) ) . determination of @xmath89 is somewhat ambiguous here as the relevant bubbles are thick wall bubbles as seen in fig.(2 ) . here there is no clear demarcation between the core region and the surface region which could give an estimate of @xmath89 . essentially , there is no core at all and the whole bubble is characterized by the overlap of bubble wall region . we can take , as an estimate for the bubble radius @xmath89 any value from 1 fm - 1.5 fm . it is important to note here that this estimate of @xmath89 is only for the calculation of nucleation rate @xmath73 , and not for using the bubble profile for actual simulation . when bubbles are nucleated in the background of false vacuum with @xmath105 , a reasonably larger size of the bubble is used so that cutting off the profile at that radius does not lead to computational errors and field evolution remains smooth . once we have an estimate of @xmath89 , we can then estimate the surface tension @xmath55 ( which also is not unambiguous here ) as follows . with the realization that essentially there is no core region for the bubbles in fig(2 ) , we say that the entire energy of the bubble ( i.e. the value of @xmath85 ) comes from the surface energy . then we write @xmath106 for @xmath85 = 240 mev , we get @xmath107 mev/@xmath95 if we take @xmath89 = 1.5 fm . with @xmath89 = 1.0 fm , we get @xmath55 = 20 mev/@xmath95 . number of bubbles expected can now be calculated for the case when nucleation rate is given by eq.(10 ) . we find number of bubbles to be about 10@xmath108 with @xmath89 taken as 1.5 fm . this is in accordance with the results discussed in ref . the bubble number increases by about a factor 5 if @xmath89 is taken to be about 1 fm . thus , with the estimates based on eq.(10 ) , bubble nucleation is a rare event for the time available for rhice . as we have mentioned above , for us the bubble nucleation on one hand represents the possibility of actual dynamics of a first order transition , while on the other hand , it represents the generic properties of the domain structure arising from a c - d transition , which may very well be a cross - over , occurring in a finite time . with this view , and with various uncertainties in the determination of pre - exponential factors in the nucleation rate , we will consider a larger number of bubbles also and study domain wall and string production . first we will consider nucleation of 5 bubbles and then we will consider nucleation of 9 bubbles to get a better network of domain walls and strings . in our simulation critical bubbles are nucleated at a time when the temperature @xmath94 crosses the value @xmath101 mev during the initial stage between @xmath61 to @xmath109 fm ( during which we have modeled the system temperature to increase linearly from 0 to @xmath60 ) . we take @xmath110 mev so bubble nucleation stage is taken to be at @xmath111 fm when @xmath94 reaches the value 200 mev . again , this is an approximation since in realistic case bubbles will nucleate over a span of time given by the ( time dependent ) nucleation rate , which could lead to a spectrum of sizes of expanding bubbles at a given time . however , due to very short time available to complete the nucleation of qgp bubbles in the background of confined phase , bubbles will have very little time to expand during the nucleation period of all bubbles ( especially as initial bubble expansion velocity is zero ) . thus it is reasonable to assume that all the bubbles nucleate at the same time . after nucleation , bubbles are evolved by the time dependent equations of motion in the minkowski space @xcite as appropriate for bjorken s longitudinal scaling model . @xmath112 with @xmath113 at @xmath11 = 0 . here @xmath114 , and dot indicates derivative with respect to the proper time @xmath11 . the bubble evolution was numerically implemented by a stabilized leapfrog algorithm of second order accuracy both in space and in time with the second order derivatives of @xmath115 approximated by a diamond shaped grid . here we follow the approach described in @xcite to simulate the first order transition . we need to nucleate several bubbles randomly choosing the corresponding z(3 ) vacua for each bubble . this is done by randomly choosing the location of the center of each bubble with some specified probability per unit time per unit volume . before nucleating a bubble , it is checked if the relevant region is in the false vacuum ( i.e. it does not overlap with some other bubble already nucleated ) . in case there is an overlap , the nucleation of the new bubble is skipped . the orientation of @xmath77 inside each bubble is taken to randomly vary between the three z(3 ) vacua . for representing the situation of relativistic heavy ion collision experiments , the simulation of the phase transition is carried out by nucleating bubbles on a square lattice with physical size of 16 fm within a circular boundary ( roughly the gold nucleus size ) . we use fixed boundary condition , free boundary condition , as well as periodic boundary condition for the square lattice . to minimize the effects of boundary ( reflections for fixed boundary , mirror reflections for periodic boundary conditions ) , we present results for free boundary conditions ( for other cases , the qualitative aspects of our results remain unchanged ) . even for free boundary conditions , spurious partial reflections occur , and to minimize these effects we use a thin strip ( of 10 lattice points ) near each boundary where extra dissipation is introduced . we use 2000 @xmath116 2000 lattice . for the physical size of 16 fm , we have @xmath117 = 0.008 fm . to satisfy the courant stability criteria , we use @xmath118 , as well as @xmath119 , ( which we use for the results presented in the paper ) . for au - au collision at 200 gev , the thermalization is expected to happen within 1 fm time . as mentioned above , in this pre - equilibrium stage , we model the system as being in a quasi - equilibrium stage with a temperature which increases linearly with time ( for simplicity ) . the temperature of the system is taken to reach upto 400 mev in 1 fm time , starting from @xmath94 = 0 . after @xmath109 fm , the temperature decreases due to continued longitudinal expansion , i.e. @xmath120 the stability of the simulation is checked by checking the variation of total energy of the system during the evolution . the energy fluctuation remains within few percent , with no net increase or decrease in the energy ( for fixed and periodic boundary conditions , and without the dissipative @xmath121 term in eq.(16 ) ) showing the stability of the simulation . the bubbles grow and eventually start coalescing , leading to a domain like structure . domain walls are formed between regions corresponding to different z(3 ) vacua , and strings form at junctions of z(3 ) domain walls . recall that the domain wall network is formed here in the transverse plane , appearing as curves . these are the cross - sections of the walls which are formed by elongation ( stretching ) of these curves in the longitudinal direction into sheets . at the intersection of these walls , strings form . in the transverse plane , these strings looks like vortices , which will be elongated into strings in the longitudinal direction . we now discuss the effects of quarks . as we mentioned above , we will follow the approach where the presence of quarks is interpreted as leading to explicit breaking of the z(3 ) symmetry , lifting the degeneracy of different z(3 ) vacua @xcite . this has important effects in the context of our model . first of all , different vacua having different energies implies different nucleation rates for the qgp bubbles with different z(3 ) vacua . further , for non - degenerate vacua , even planar @xmath0 interfaces do not remain static , and move away from the region with the unique true vacuum . thus , while for the degenerate vacua case every closed domain wall collapses , for the non - degenerate case this is not true any more . a closed wall enclosing the true vacuum may expand if it is large enough so that the surface energy contribution does not dominate ( this is essentially the same argument as given for the bubble expansion , see eq.(5 ) and the discussion following it ) . to see the importance of these effects we need an estimate of the explicit symmetry breaking term arising from inclusion of quarks . for this we use the estimates given in @xcite . even though the estimates in ref.@xcite are given in the high temperature limit , we will use these for temperatures relevant for our case , i.e. @xmath122 mev , to get some idea of the effects of the explicit symmetry breaking . the difference in the potential energy between the true vacuum with @xmath123 and the other two vacua ( @xmath124 , and @xmath125 , which are degenerate with each other ) is estimated in ref . @xcite to be , @xmath126 where @xmath127 is the number of massless quarks . if we take @xmath128 then @xmath129 . at the bubble nucleation temperature ( which we have taken to be about @xmath101 mev , the difference between the false vacuum and the true vacuum is about 150 mev/@xmath130 while @xmath131 at @xmath101 mev is about four times larger , equal to 600 mev/@xmath130 . as @xmath94 approaches @xmath2 , this difference will become larger as the metastable vacuum and the stable vacuum become degenerate at @xmath2 , while @xmath131 remains non - zero . for @xmath94 near 250 mev ( where the barrier between the metastable vacuum and the stable vacuum disappears ) , @xmath131 becomes almost comparable to the difference between the potential energy of the false vacuum ( the confining vacuum ) and the true vacuum ( deconfined vacuum ) . it does not seem reasonable that at temperatures of order 200 mev a qgp phase ( with quarks ) has higher free energy than the hadronic phase . this situation can be avoided if the estimates of eq.(18 ) are lowered by about a factor of 5 so that these phases have lower free energy than the confining phase . ( a more desirable situation will be when @xmath131 approaches zero as the confining vacuum and the deconfining ( true ) vacuum become degenerate at @xmath2 . ) it is in the spirit of the expectation that explicit breaking of z(3 ) is small near @xmath2 for finite pion mass @xcite . even with such lower estimates , the effects of quarks may give different nucleation probabilities for different z(3 ) vacua . however , in this paper we will ignore this possibility . this may not be very unreasonable as for thick wall bubbles thermal fluctuations may be dominant in determining the small number of bubbles nucleated during the short span of time available . for very few bubbles nucleated , there may be a good fraction of events where different z(3 ) vacua may occur in good fraction . also note that the pre - exponential factor for the bubble nucleation rate of eq.(6 ) , as given in eq.(9 ) increases with the value of @xmath68 . thus , for the range of values of @xmath68 for which the exponential factor in eq.(6 ) is of order 1 , which is likely in our case , the nucleation rate may not decrease with larger values of @xmath68 , i.e. for the z(3 ) vacua with higher potential energies than the true vacuum . ( of course for very large values of @xmath68 the exponential term will suppress the nucleation rate . ) thus our assumption of neglecting quark effects for the bubble nucleation rate may not be unreasonable . we now consider the effect of non - zero @xmath131 , as in eq.(18 ) , on the evolution of closed domain walls . the temperature range relevant for our case is @xmath132 mev . in an earlier work we had numerically estimated the surface tension of z(3 ) walls to be about 0.34 and 7.0 gev/@xmath95 for @xmath94 = 200 and 400 mev respectively . the effects of quarks will be significant if a closed spherical wall ( with true vacuum inside ) starts expanding instead of collapsing . again , using the bubble free energy eq.(5 ) , with @xmath133 and @xmath55 as the surface energy of the interface , we see that the critical radius @xmath134 of the spherical wall is @xmath135 for @xmath94 = 200 mev and 400 mev we get @xmath136 and 1.5 fm respectively . though these values are not large , these are not too small either when considering the fact that relevant sizes and times for rhice are of order few fm anyway . the values of @xmath134 we estimated here are very crude as for these sizes wall thickness is comparable to @xmath134 hence application of eq.(5 ) , separating volume and surface energy contributions , is not appropriate . further , as we discussed above , the estimate in eq.(18 ) which is applicable for high temperature limit , seems an over estimate by about an order of magnitude at these temperatures . thus uncertainties of factors of order 1 may not be unreasonable to expect . in that case the dynamics of closed domain walls of even several fm diameter will not be affected by the effects of quarks via eq.(18 ) . we will see in the next section of simulation results that the domain walls and strings typically have large velocities ( e.g. about 0.5 - 0.8 ) at the time of formation . these result from momentum of colliding bubble walls and from curvature in the shape of these walls ( as well as asymmetries in the profiles of strings ) at the time of formation . with such large velocities present , the effects of pressure differences between different z(3 ) vacua due to quarks may become subdominant in studying the evolution of these structures for the short time duration available for rhice . with this , we will assume that for small closed walls , of order few fm diameter , as is expected in rhice , the quark effects in the evolution of wall network may be neglected . we plan to remove these assumptions and include the effects of non - zero @xmath131 due to quarks on bubble nucleation and wall evolution in a future work . as we mentioned above , the number of bubbles expected to form in rhice is small . we first present and discuss the case of 5 bubbles which is more realistic from the point of view of nucleation estimates given by eq.(6 ) ( though a gross over - estimate for eq.(10 ) ) . note that a domain wall will form even if only two bubbles nucleate ( with different z(3 ) vacua ) . however , to see qgp string formation , we need nucleation of at least three bubbles . next we will discuss the case of 9 bubbles which is a much more optimistic estimate of the nucleation rate ( even for eq.(6 ) ) . alternatively , this case can be taken as better representation of the case when the transition is a cross over and bubbles only represent a means for developing a domain structure expected after the cross - over is completed . ( in this case only relevant energy density fluctuations , as discussed below , will be those arising from z(3 ) walls and strings , and not the ones resulting from bubble wall coalescence . ) fig.3 - 7 show the results of simulation when five bubbles are nucleated with random choices of different z(3 ) vacua inside each bubble . fig.3 shows a time sequence of surface plots of the order parameter @xmath1 in the two dimensional lattice . fig.3a shows the initial profiles of the bubbles of the qgp phase embedded in the confining vacuum with @xmath44 at @xmath11 = 0.5 fm with the temperature @xmath66 200 mev . ( recall that for initial 1 fm time the temperature is taken to linearly increase from zero to @xmath60 = 400 mev . ) the radial profile of each bubble is truncated with appropriate care of smoothness on the lattice for proper time evolution . fig.3b shows the profile of each bubble at @xmath137 1.5 fm showing the expansion of the bubbles . near the outer region of a bubble the field grows more quickly towards the true vacuum . if bubbles expand for long time then bubble walls become ultra - relativistic and undergo large lorentz contraction . this causes problem in simulation ( see , e.g. @xcite ) . in our case this situation arises at outer boundaries ( for the inner regions bubbles collide quickly ) . for outer regions also it does not cause serious problem because of the use of dissipative boundary strip ( as explained above in sect.v ) . \(a ) and ( b ) show plots of profiles of @xmath77 at @xmath138 0.5 fm and 1.5 fm respectively . ( c)-(i ) show plots of @xmath139 at @xmath137 1.5 , 2.5 , 4.0 , 6.0 , 9.0 , 11.0 , and 13.7 fm . @xmath94 drops to below @xmath2 around at @xmath137 10.5 fm and @xmath66 167 mev at @xmath137 13.7 fm . formation of domain walls and string and antistring ( at junctions of three walls ) can be seen in the plots in ( e ) - ( h ) . [ fig.3 ] figs . 3c-3i show plots of @xmath139 clearly showing formation of domain walls and strings ( junctions of three walls ) . here @xmath40 is a reference vacuum expectation value of @xmath77 calculated at the maximum temperature @xmath140 400 mev . formation of domain walls , extending through the entire qgp region , is directly visible from fig.3e ( at @xmath141 fm ) onwards . the temperature drops to below @xmath142 mev at @xmath143 fm . the last plot in fig.3i is at @xmath144 fm when the temperature @xmath66 167 mev , clearly showing that the domain walls have decayed away in the confined phase and the field is fluctuating about @xmath44 . plots of the phase @xmath33 of the order parameter @xmath77 . ( a ) shows the initial distribution of @xmath33 in the bubbles at @xmath138 0.5 fm . ( b ) - ( f ) show plots of @xmath33 at @xmath137 2.0 , 4.6 , 11.0 , 12.2 , and 13.7 fm respectively . location of domain walls and the string ( with positive winding ) and antistring ( with negative winding ) are clearly seen in the plots in ( b)-(e ) . the motion of the antistring and associated walls can be directly seen from these plots and an estimate of the velocity can be obtained . [ fig.4 ] in fig.3f-3h we see two junctions of three domain walls where the qgp strings form . this is seen more clearly in fig.4 where the phase @xmath33 of @xmath77 is plotted ( with the convention that @xmath33 is the angle of the arrow from the positive @xmath145 axis ) . the domain walls are identified as the boundaries where two different values of @xmath33 meet , and strings correspond to the non - trivial winding of @xmath33 at the junctions of three walls . from fig.4b , c we clearly see that at one of the junctions we have a string ( at @xmath146 5 fm , @xmath147 8 fm ) with positive winding and we have an anti - string at @xmath146 9 fm , @xmath148 8 fm with negative winding . note the rapid motion of the walls forming the antistring towards positive @xmath149 axis from fig.4c ( at @xmath138 4.6 fm ) to fig.4e ( at @xmath138 12.2 fm ) . the average speed of the antistring ( and wall associated with that ) can be directly estimated from these figures to be about 0.5 ( in natural units with @xmath150 ) . this result is important in view of the discussion in the preceding section showing that effects of pressure differences between different z(3 ) vacua , arising from quarks , may be dominated by such random velocities present for the walls and strings at the time of formation . the motion of the walls here is a direct result of the straightening of the @xmath151 shaped wall structure due to its surface tension . for the same reason the wall in the left part of fig.4b also straightens from the initial wedge shape . fig.4f shows almost random variations of @xmath33 at @xmath144 fm when the temperature is 167 mev , well below the critical temperature . though it is interesting to note that a large region of roughly uniform values of @xmath33 still survives at this stage . surface plots of the local energy density @xmath152 in gev/@xmath130 . ( a ) - ( f ) show plots at @xmath137 3.0 , 3.6 , 5.0 , 6.0 , 8.0 , and 13.2 fm respectively . extended domain walls can be seen from these plots of @xmath153 in ( b ) - ( e ) . small peaks in @xmath153 exist at the locations of string and antistring ( larger peaks arise from oscillations of field where bubbles coalesce ) . plot in ( f ) is at the stage when @xmath66 169 mev and domain walls have decayed away . [ fig.5 ] fig.5 shows surface plots of the local energy density @xmath153 . @xmath153 is plotted in units of gev/@xmath130 . although the simulation is 2 + 1 dimensional representing the transverse plane of the qgp system , we calculate energy in 3 + 1 dimensions by taking a thickness of 1 fm in the central rapidity region . fig.5a shows plot at @xmath138 3 fm when bubbles have coalesced . in fig.5b at @xmath154 3.6 fm we see that bubble walls have almost decayed ( in ripples of @xmath77 waves ) between the bubbles with same @xmath155 ( i.e. same z(3 ) vacua ) as can be checked from @xmath33 plots in fig.4 . energy density remains well localized in the regions where domain walls exist . also , one can see the small peaks in the energy density where strings and antistrings exist . large peaks arise from oscillations of @xmath77 when bubble walls coalesce , as discussed in @xcite . large values of @xmath153 near the boundary of the lattice are due to relativistically expanding bubble walls . motion of walls and generation of increased fluctuations in energy density are seen in fig.5c-5e . fig.5f at @xmath138 13.2 fm ( with @xmath94 = 169 mev ) shows that walls have decayed . however , some extended regions of high energy density can be seen at this stage also . contour plots of the local energy density @xmath153 at different stages . plots in ( a ) - ( f ) correspond to @xmath137 3.0 , 3.6 , 5.0 , 7.6 , 10.2 , and 13.2 fm respectively . structure of domains walls formed near the coalescence region of bubbles with different @xmath33 is clear in ( b ) , whereas the bubble walls at lower half of @xmath149 region , and near @xmath156 10 fm , are seen to simply decay away due to same vacuum in the colliding bubbles . motion of the antistring and associated domain walls is clear from plots in ( b ) - ( e ) . the last plot in ( f ) is at @xmath157 fm when @xmath94 = 169 mev . [ fig.6 ] fig.6 shows contour plots of energy density @xmath153 . fig.6a shows coalescence of bubbles at @xmath137 3 fm . fig.6b at @xmath154 3.6 fm clearly shows the difference in the wall coalescence depending on the vacua in the colliding bubbles . where domain walls exist , we see extended regions of high energy density contours whereas where the two vacua in colliding bubbles are same , there are essentially no high energy density contours . motion of domain walls ( and strings at wall junctions ) is clearly seen in these contour plots in fig.6b-6d . fig.6e is at @xmath138 10.2 fm when @xmath94 drops to @xmath2 . wall structures are still present . fig.6f is at @xmath137 13.2 fm ( @xmath94 = 169 mev ) when walls have decayed away , though some extended structures in contours still survive . we have also calculated the variance of energy density @xmath158 at each time stage to study how energy fluctuations change during the evolution . in fig.7 we show the plot of @xmath159 as a function of proper time . here @xmath153 is the average value of energy density at that time stage . the energy density @xmath153 decreases due to longitudinal expansion , hence we plot this ratio to get an idea of relative importance of energy density fluctuations . fig.7 shows initial rapid drop in @xmath159 due to large increase in @xmath153 during the heating stage upto @xmath11 = 1 fm , followed by a rise due to increased energy density fluctuations during the stage when bubbles coalesce and bubble walls decay , as expected . interesting thing to note is a slight peak in the plot near @xmath138 10.5 fm when @xmath94 drops below @xmath2 . this should correspond to the decay of domain walls and may provide a signal for the formation and subsequent decay of such objects in rhice . plot of the ratio of variance of energy density @xmath160 and the average energy density @xmath153 as a function of proper time . energy fluctuations increase during the initial stages when bubbles coalesce and bubble walls decay . after that there is a slow decrease in energy fluctuation until the stage when the temperature drops below @xmath2 and @xmath143 fm . energy fluctuations increase after this stage . note small peak near the transition stage . [ fig.7 ] fig.8 - 12 show the results of simulation where nine bubbles are nucleated . fig.8 shows a time sequence of surface plots of @xmath1 ( similar to fig.3 ) . fig.8a shows the initial profiles of the qgp bubbles at @xmath11 = 0.5 fm with the nucleation temperature of @xmath66 200 mev . fig.8b shows the profile of @xmath77 for the bubbles at @xmath137 1.5 fm showing the expansion of the bubbles . fig.8c-8i show plots of @xmath139 at different stages . noteworthy here is the formation of a closed domain wall near the central region which is clearly first seen in fig.8e at @xmath137 5 fm . the collapse of this closed domain wall is seen in the subsequent plots with the closed wall completely collapsing away in fig.8h at @xmath137 9.6 fm . only surviving structure is an extended domain wall along the @xmath145 axis . fig.8i is at @xmath157 fm when @xmath66 169 mev . the domain walls have decayed away and @xmath77 fluctuates about the value zero as appropriate for the confined phase . \(a ) and ( b ) show plots of profiles of @xmath77 at @xmath138 0.5 fm and 1.5 fm respectively for the case when 9 bubbles are nucleated . ( c)-(i ) show plots of @xmath139 at @xmath137 2.0 , 3.0 , 5.0 , 7.0 , 8.6 , 9.6 , and 13.2 fm respectively . formation of a closed domain wall is first clearly seen in the plot in ( e ) . this closed domain wall collapses as seen in plots in ( e ) through ( h ) . only surviving domain wall is an extended wall along @xmath145 axis in ( h ) . plot in ( i ) is when the temperature @xmath66 169 mev . [ fig.8 ] fig.9 shows plots of the phase @xmath33 of @xmath77 at different stages . initial phase distribution in different bubbles is shown in fig.9a at @xmath161 fm . fig.9b shows the formation of closed , elliptical shaped domain wall at @xmath162 fm . strings and antistrings can also be identified by checking the windings of @xmath33 . the closed domain wall collapses , and in the process becomes more circular , as shown in the plots in fig.9b-9h . fig.9h shows the plot at @xmath137 9.6 fm when the closed domain wall completely collapses away , leaving only an extended domain wall running along @xmath145 axis between @xmath163 fm . the final fig.9i at @xmath164 fm is when the temperature @xmath165 167 mev showing random fluctuations of @xmath33 when domain walls have decayed away in the confining phase . plots of the phase @xmath33 of @xmath77 . ( a ) shows initial distribution of @xmath33 in the bubbles at @xmath138 0.5 fm . ( b ) - ( i ) show plots of @xmath33 at @xmath137 2.6 , 5.0 , 6.0 , 7.0 , 8.0 , 8.6 , 9.6 , and 13.8 fm respectively . ( b ) shows formation of elliptical shaped closed domain wall which subsequently becomes more circular as it collapses away by @xmath137 9.6 fm as shown by the plot in ( h ) . the plot in ( i ) is at @xmath166 mev showing random fluctuations of @xmath33 . [ fig.9 ] fig.10 shows the surface plot of energy density @xmath153 at different stages . extended thin regions of large values of @xmath153 are clearly seen in the plots corresponding to domain walls . collapse of the closed domain wall is also clearly seen in fig.10c-10 g . important thing to note here is the surviving peak in the energy density plot at the location of domain wall collapse . this peak survives even at the stage shown in fig.10i at @xmath157 fm when @xmath167 mev , well below the transition temperature . such _ hot spots _ may be the clearest signals of formation and collapse of z(3 ) walls . surface plots of the local energy density @xmath153 in gev/@xmath130 . ( a ) - ( i ) show plots at @xmath137 2.6 , 3.5 , 4.6 , 5.6 , 7.0 , 8.6 , 9.6 , 11.2 , and 13.2 fm respectively . formation and subsequent collapse of closed domain wall is clearly seen in plots in ( c ) through ( g ) . note that the strong peak in @xmath153 resulting from domain wall collapse ( the _ hot spot _ ) survives in ( i ) when @xmath94 = 169 mev . [ fig.10 ] contour plots of @xmath153 are shown in fig.11 . though closed domain wall can be seen already in fig.11b ( at @xmath137 3.5 fm ) , the domain wall is still attached to outward expanding bubble walls near @xmath156 3 fm , @xmath168 12 fm which affects the evolution / motion of that portion of the domain wall . formation of distinct closed wall structure is first visible in fig.11c at @xmath1384.6 fm . subsequent plots clearly show how the domain wall becomes circular and finally collapses away by fig.11k at @xmath169 fm . note the survival of the _ hot spot _ even at the stage shown in fig.11_l _ at @xmath157 fm when @xmath66 169 mev . one can make a rough estimate of the velocity of the closed wall during its collapse from these plots . in fig.11c , at @xmath137 4.6 fm , the @xmath145 extent of the closed wall is about 8 fm and the @xmath149 extent is about 5 fm . the wall collapses away by the stage in fig.11k at @xmath137 9.6 fm . this gives rough velocity of collapse in @xmath145 direction to be about 0.8 while the velocity in @xmath149 direction is about 0.5 . note that here , as well as in fig.4 for the five bubble case , the estimate of the wall velocity is not affected by the extra dissipation which is introduced only in a very thin strip ( consisting of ten lattice points ) near the lattice boundary . formation and collapse of such closed domain walls is important as the resulting hot spot can lead to important experimental signatures . further , such closed domain wall structures are crucial in the studies of @xmath3 enhancement , especially for heavy flavor hadrons as discussed in @xcite contour plots of the local energy density @xmath153 at different stages . plots in ( a ) - ( l ) correspond to @xmath137 2.6 , 3.5 , 4.6 , 6.0 , 6.6 , 7.0 , 7.6 , 8.0 , 8.6 , 9.0 , 9.6 , and 13.2 fm respectively . formation of distinct closed wall structure is first visible in ( c ) at @xmath1384.6 fm . subsequent plots show the collapse of this domain wall as it becomes more circular . the wall finally collapses away in ( k ) at @xmath169 fm . note that concentration of energy density at the location of domain wall collapse ( the _ hot spot _ ) survives even at the stage shown in ( l ) at @xmath157 fm when @xmath66 169 mev . [ fig.11 ] fig.12 shows the evolution of the ratio of the variance of energy density and the average energy density . as for the five bubble case , initial drop and rise are due to heating stage upto @xmath137 1 fm and subsequent bubble coalescence and decay of bubble walls . in this case the ratio remain roughly constant upto @xmath170 10.5 fm which is the transition stage to the confining phase . this is the stage when the surviving extended domain wall starts decaying . this is also the stage soon after the closed domain wall collapses away . the prominent peak at this stage should be a combined result of both of these effects . the large increase in the variance of energy density at this stage should be detectable from the analysis of particle distributions and should be a clear signal of hot spots resulting from collapse of closed walls and the decay of any surviving domain walls . plot of the ratio of variance of energy density @xmath158 and the average energy density @xmath153 as a function of proper time . energy fluctuations increase during the initial stages when bubbles coalesce and bubble walls decay . after that @xmath159 remains roughly constant until the stage when the temperature drops below @xmath2 at @xmath143 fm . this is also the stage just after the collapse of the closed domain wall . energy fluctuations sharply increase around this stage . note the prominent peak at this stage . the @xmath0 wall network and associated strings form during the early confinement - deconfinement phase transition . they undergo evolution in an expanding plasma with decreasing temperature , and eventually melt away when the temperature drops below the deconfinement - confinement phase transition temperature . they may leave their signatures in the distribution of final particles due to large concentration of energy density in extended regions as well as due to non - trivial scatterings of quarks and antiquarks with these objects . first , we focus on the extended regions of high energy density resulting from the domain walls and strings . this is clearly seen in our simulations and some extended structures / hot spots also survive after the temperature drops below the transition temperature @xmath2 . note that even the hot spot resulting from the collapse of closed domain wall in fig.9,10 will be stretched in the longitudinal direction into an extended linear structure ( resulting from the collapse of a cylindrical wall ) . we know that at rhic energies , the final freezeout temperature is not too far below the transition temperature @xmath2 . this means that the energy density concentrated in any extended ( sheet like for domain walls and line like for strings / hot spots ) regions may not be able to defuse away effectively . assuming local energy density to directly result in multiplicity of particles coming from that region , an analysis of particle distribution in @xmath3 and in rapidity should be able to reflect any such extended regions . in this context , it will be interesting to investigate if the ridge phenomenon seen at rhic @xcite could be a manifestation of an underlying z(3 ) domain wall / string structure . correlation of particle production over large range of rapidity will naturally result from longitudinally extended regions of high energy density ( _ hot spots _ in the transverse plane ) . combined with flow effects it may lead to ridge like structures @xcite . if extended domain wall structure survives in the transverse plane also , this will then extend to sheet like regions in the longitudinal direction . decay of such a region of high energy density may directly lead to a ridge like structure , without requiring flow effects . we expect non - trivial signatures resulting from the consideration of interactions of quarks and antiquarks with domain walls . it was shown in an earlier work @xcite using generic arguments that quarks and antiquarks should have non - zero reflection coefficients when traversing across these domain walls . a collapsing domain wall will then concentrate any excess baryon number enclosed , leading to formation of baryon rich regions . this is just like witten s scenario for the early universe @xcite ( which was applied for the case of rhice in ref . however , for these works it was crucial that the quark - hadron transition be of ( strong ) first order . as we have emphasized above , in our case formation of z(3 ) walls and strings will be a generic feature of any c - d phase transition . even though we have implemented it in the context of a first order transition via bubble nucleation , these objects will form even if the transition is a cross - over . thus , concentration of baryons in small regions should be expected to occur in rhice which should manifest in baryon concentration in small regions of rapidity and @xmath3 . another important aspect of quark / antiquark reflection is that inside a collapsing wall , each reflection increases the momentum of the enclosed particle . when closed domain walls collapse then enclosed quarks / antiquarks may undergo multiple reflections before finally getting out . this leads to a specific pattern of @xmath3 enhancement of quarks with heavy flavors showing more prominent effects @xcite . the modification of @xmath3 spectrum of resulting hadrons can be calculated , and the enhancement of heavy flavor hadrons at high @xmath3 can be analyzed for the signal for the formation of z(3 ) domain walls in these experiments @xcite . in our simulations extended domain walls also form which show bulk motion with velocities of order 0.5 . quarks / antiquarks reflected from such moving extended walls will lead to anisotropic momentum distribution of emitted particles which may also provide signature of such walls . for collapsing closed domain walls , spherical domain walls were used for estimates in ref . @xcite and in ref . our simulation in the present work provides a more realistic distribution of shapes and sizes for the resulting domain wall network . we have estimated the velocity of moving domain walls to range from 0.5 to 0.8 for the situations studied . these velocities are large enough to have important effect on the momentum of quarks / antiquarks undergoing reflection from these walls . one needs to combine the analysis of @xcite with the present simulation to get a concrete signature for baryon concentration and heavy flavor hadron @xmath3 spectrum modification . we plan to carry this out in a future work . we also plan to study effects of spontaneous violation of cp due to formation of these z(3 ) walls in rhice . our results show interesting pattern of the evolution of the fluctuations in the energy density . as seen in fig.7 and fig.12 , energy density fluctuations show rapid changes during stages of bubble wall coalescence and during collapse / decay of domain walls . even string - antistring annihilations should be contributing to these fluctuations . fluctuations near the transition stage may leave direct imprints on particle distributions . it is intriguing to think whether dileptons or direct photons may be sensitive to these fluctuations , which could then give a time history of evolution of such energy density fluctuations during the early stages as well . even the presence of domain walls and strings during early stages may affect quark - antiquark distributions in those regions which may leave imprints on dileptons / direct photons . an important point to note is that in our model , we expect energy density fluctuations in event averages ( representing high energy density regions of domain walls / strings as discussed above ) , as well as event - by - event fluctuations . these will result due to fluctuation in the number / geometry of domain walls / strings from one event to the other resulting from different distribution of ( randomly occurring ) z(3 ) vacua in the qgp bubbles . even the number of qgp bubbles , governed by the nucleation probability , will vary from one event to the other contributing to these event - by - event fluctuations . we have carried out numerical simulation of formation of @xmath0 interfaces and associated strings at the initial confinement - deconfinement phase transition during the pre - equilibrium stage in relativistic heavy - ion collision experiments . a simple model of quasi - equilibrium system was assumed for this stage with an effective temperature which first rises ( with rapid particle production ) to a maximum temperature @xmath4 , and then decreases due to continued plasma expansion . using the effective potential for the polyakov loop expectation value @xmath1 from ref . @xcite we study the dynamics of the ( c - d ) phase transition in the temperature / time range when the first order transition of this model proceeds via bubble nucleation . as we have emphasized above , though our study is in the context of a first order transition , its results are expected to be valid even when the transition is a cross - over . ( though for non - zero chemical potential the transition may indeed be of first order ) . the generic nature of our results arises due to the fact that the formation of z(3 ) domain walls and associated strings happens due to the a general domain structure resulting after any transition ( occurring in a finite time ) . this is the essential physics of the kibble mechanism underlying the formation of topological defects in symmetry breaking transitions . the @xmath0 wall network and associated strings formed during this early c - d transition are evolved using field equations in a plasma which is longitudinally expanding , with decreasing temperature . we have neglected here the transverse expansion which is a good approximation for the early stages near the formation stage of these objects , but may not be a good approximation for the later parts of simulations when temperature drops below @xmath2 and z(3 ) domain walls and strings melt away . we have studied size / shape of resulting closed domain wall as well as extended domain walls and have estimated the velocities of walls to range from 0.5 to 0.8 . we also calculate the energy density fluctuations expected due to formation of these objects . various experimental signals which can indicate the formation of these topologically non - trivial objects in rhice have been discussed . for example , existence of these objects will result in specific patterns of energy density fluctuations which may leave direct imprints on particle distributions . in our model , we expect energy density fluctuations in event averages ( representing high energy density regions of domain walls / strings ) , as well as event - by - event fluctuations as the number / geometry of domain walls / strings and even the number of qgp bubbles , varies from one event to the other . extended regions of large energy densities arising from z(3 ) walls and associated strings may be manifested in space - time reconstruction of hadron density ( using hydrodynamic model ) . the correlation of particle production over large range of rapidity will be expected from such extended regions . this , combined with the flow effects ( for string like regions ) , or possibly directly ( for sheet like extended region ) may provide an explanation for the ridge phenomena observed at rhic @xcite . also , from the reflection of quarks and antiquarks from collapsing domain walls , baryon number enhancement in localized regions ( due to concentration of net baryon number ) as well as enhancement of heavy flavor hadrons at high @xmath3 is expected . we emphasize again that the presence of @xmath0 walls and string may not only provide qualitatively new signatures for the qgp phase in these experiments , it may provide the first ( and may be the only possible ) laboratory study of such topological objects in a relativistic quantum field theory system . we are very grateful to sanatan digal , anjishnu sarkar , ananta p. mishra , p.s . saumia , and abhishek atreya for very useful comments and suggestions . usg , ams , and vkt acknowledge the support of the department of atomic energy- board of research in nuclear sciences ( dae - brns ) , india , under the research grant no 2008/37/13/brns . usg and vkt acknowledge support of the computing facility developed by the nuclear - particle physics group of physics department , allahabad university under the center of advanced studies ( cas ) funding of ugc , india . u. w. heinz , lectures given at 2nd latin american school of high - energy physics , san miguel regla , mexico , 1 - 14 jun 2003 , published in _ san miguel regla 2003 , high - energy physics _ 165 . e - print : hep - ph/0407360 ; j. adams et al . [ star collaboration ] , j. phys . * g 32 * , l37,(2006 ) [ arxiv : nucl - ex/0509030 ] ; j.putschke , talk at quark matter 2006 for star collaboration ) , shanghai , nov.2006 ; s. a. voloshin , phys . lett . * b 632 * , 490 ( 2006)[arxiv : nucl - th/0312065 ] .

we study the dynamics of confinement - deconfinement ( c - d ) phase transition in the context of relativistic heavy - ion collisions within the framework of effective models for the polyakov loop order parameter . we study the formation of @xmath0 walls and associated strings in the initial transition from the confining ( hadronic ) phase to the deconfining ( qgp ) phase via the so called kibble mechanism . essential physics of the kibble mechanism is contained in a sort of domain structure arising after any phase transition which represents random variation of the order parameter at distances beyond the typical correlation length . we implement this domain structure by using the polyakov loop effective model with a first order phase transition and confine ourselves with temperature / time ranges so that the first order c - d transition proceeds via bubble nucleation , leading to a well defined domain structure . the formation of @xmath0 walls and associated strings results from the coalescence of qgp bubbles expanding in the confining background . we investigate the evolution of the @xmath0 wall and string network . we also calculate the energy density fluctuations associated with @xmath0 wall network and strings which decay away after the temperature drops below the quark - hadron transition temperature during the expansion of qgp . we discuss evolution of these quantities with changing temperature via bjorken s hydrodynamical model and discuss possible experimental signatures resulting from the presence of @xmath0 wall network and associate strings . key words : quark - hadron transition , relativistic heavy - ion collisions , z(3 ) domain walls

quite a few independent observable quantities can be measured in a long - duration gamma - ray burst ( grb ) . these include its spherical equivalent energy , its peak isotropic luminosity , the ` peak energy ' of its spectrum and the red - shift of its host galaxy . in order of increasing effort on the data analysis , one can also define and determine the number of pulses in the grb s light - curve and their widths , rise - times , and ` lag - times ' . finally , with considerable toil and embarrassment of choices , one can define and measure ` variability ' ( fenimore & ramirez - ruiz , 2000 ; plaga , 2001 ; reichart et al . 2001 ; guidorzi et al . 2006 ; schaefer 2006 ) . pairs of the above quantities are known to be correlated as approximate power laws , sometimes fairly tightly and over spans of several orders of magnitude . a model of grbs ought to be able to predict these power laws and to pin - point the choices of red - shift corrections that should make them tightest . in the ` cannonball ' ( cb ) model of grbs the correlations between the cited observables , as we shall discuss , are predictable . they are based on very simple physics : the production of @xmath0 rays by inverse compton scattering of much softer photons by a relativistically - moving , quasi - point - like object ( shaviv & dar 1995 , dar & de rjula 2004 ) . the correlations very satisfactorily test these individual theoretical ingredients , or combinations thereof . a reader desiring to start by evaluating these claims may choose to read section [ basis ] first . the data , particularly on grbs of known red - shift , has become much more extensive in the time elapsed since the cb - model correlations were predicted ( dar & de rjula 2001 ) and several of them were tested ( dar & de rjula 2004 ) . it is time to restudy the subject , which we do for many correlations , relying mainly on the data analysis by schaefer ( 2006 ) . in the cb model ( dar & de rjula 2000 , 2004 ; dado et al . 2002 , 2003 ) , _ long - duration _ grbs and their ags are produced by bipolar jets of cbs , ejected in core - collapse sn explosions ( dar & plaga 1999 ) . an accretion disk is hypothesized to be produced around the newly formed compact object , either by stellar material originally close to the surface of the imploding core and left behind by the explosion - generating outgoing shock , or by more distant stellar matter falling back after its passage ( de rjula 1987 ) . as observed in microquasars , each time part of the disk falls abruptly onto the compact object , a pair of cbs made of _ ordinary plasma _ are emitted with high bulk - motion lorentz factors , @xmath0 , in opposite directions along the rotation axis , wherefrom matter has already fallen onto the compact object , due to lack of rotational support . the @xmath0-rays of a single pulse in a grb are produced as a cb coasts through the sn _ glory _ the sn light scattered away from the radial direction by the sn and pre - sn ejecta . the electrons enclosed in the cb compton up - scatter glory s photons to grb energies . each pulse of a grb corresponds to one cb . the emission times of the individual cbs reflect the chaotic accretion process and are not predictable . at the moment , neither are the characteristic baryon number and lorentz factor of cbs , which can be inferred from the analysis of grb afterglows ( dado et al . 2002 , 2003a ) . given this information , two other ` priors ' ( the typical early luminosity of a supernova and the typical density distribution of the parent star s wind - fed circumburst material ) , and a single extra hypothesis ( that the wind s column density in the ` polar ' directions is significantly smaller than average ) all observed properties of the grb pulses can be derived ( dar & de rjula 2004 ) . all that is required are explicit simple calculations involving compton scattering . strictly speaking , our results refer to single pulses in a grb , whose properties reflect those of _ one _ cb . the statistics on single - pulse grbs of known redshift are too meager to be significant . thus , we apply our results to entire grbs , irrespective of their number of pulses , which ranges from 1 to @xmath1 . this implies averaging the properties of a grb over its distinct pulses , and is no doubt a source of dispersion in the correlations we study . cannonballs are highly relativistic , their typical lorentz factors are @xmath2 . they are quasi - point - like : the angle a cb subtends from its point of emission is comparable or smaller than the characteristic opening angle , @xmath3 , of its relativistically beamed radiation . let the typical viewing angle of an observer of a cb , relative to its direction of motion , be @xmath4(1 mrad ) , and let @xmath5 be the corresponding doppler factor : @xmath6 where the approximation is excellent for @xmath7 and @xmath8 . to correlate two grb observables , all one needs to know is their functional dependence on @xmath9 and @xmath0 . the reason is that , in eq . ( [ delta ] ) , the @xmath10 dependence of @xmath11 is so pronounced , that it may be expected to be the largest source of the case - to - case spread in the measured quantities ( for grbs of known redshift @xmath12 , the correlations are sharpened by use of the explicit @xmath12-dependences ) . in the cb model , the @xmath13 dependences of the spherical equivalent energy of a grb , @xmath14 ; its peak isotropic luminosity @xmath15 ; its peak energy , @xmath16 ( dar & de rjula 2001 ) ; and its pulse rise - time @xmath17 ( dar & de rjula 2004 ) , are : @xmath18 the first two of these results are simple consequences of relativity and the quasi - point - like character of the cb - model s sources ( they would be different for an assumed grb - generating jet with an opening angle much greater than @xmath19 ) . the expression for @xmath16 reflects the inverse compton scattering by the cb s electrons ( comoving with it with a lorentz factor @xmath0 ) of the glory s photons , that are approximately isotropic in the supernova rest system , and are doppler - shifted by the cb s motion by a factor @xmath9 ( the result would be different , for instance , for synchrotron radiation from the grb s source , or self - compton scattering of photons comoving with it ) . the expression for the pulses s rise - time has the same physical basis as that for @xmath16 , but we shall see in more detail in section [ variability ] , eq . ( [ twtrans22 ] ) , that it also reflects the production of @xmath0-rays in an illuminated , previously wind - fed medium ) have explicit dependences on the number of cbs in a grb , their initial expansion velocity and baryon number . with typical values fixed by the analysis of grb afterglows , the predictions agree with the observations ( dar & de rjula 2004 , dado et al . 2006 ) . ] . in sections [ variability ] and [ lag ] we derive the cb - model s expectation for the the variability of a grb , @xmath20 , and the prediction for the ` lag - time ' of its pulses , @xmath21 , to wit : @xmath22 the physics of the first of these relations is essentially the same as that of a pulse s rise - time . the behaviour of @xmath21 reflects the cb - model s specific prediction for how , as a pulse evolves in time , the photon s energy spectrum softens , due to the increasingly non - isotropic character of the glory s photons which the cbs encounter as they travel , and to the softening of the energy spectrum of the cb s electron population ( dar & de rjula 2004 ) . given the 6 relations in eqs . ( [ brief],[tlagv ] ) , it is straightforward to derive the 15 ensuing two - observable correlations , of which subgroups of 5 are non - redundant ( if @xmath23 is correlated to @xmath24 and @xmath24 to @xmath25 ... ) . we consider first one of these subgroups : the 5 correlations most often phenomenologically discussed to date . all these correlations are derived in the same manner . consequently , we proceed by way of example and outline only the derivation of the @xmath26 $ ] correlation ( dar & de rjula 2001 , dado et al . the full derivation is in the appendix . an @xmath26 $ ] correlation was predicted [ and tested ] in dar & de rjula ( 2001 , [ 2004 ] ) . according to eqs . ( [ brief ] ) , @xmath27 and @xmath28 . if most of the variability is attributed to the very fast - varying @xmath10-dependence of @xmath9 in eq . ( [ delta ] ) , @xmath29^{1/3}$ ] . ( dar & de rjula 2001 ) . this original expectation can be refined by exploiting another prediction ( dado et al . a typical observer s angle is @xmath30 . a relatively large @xmath16 implies a relatively large @xmath9 , and a relatively small viewing angle , @xmath31 . for @xmath32 , @xmath33 , implying that @xmath34^{2/3}$ ] _ for the largest observed values _ of @xmath14 . on the other hand , for @xmath35 , the dar & de rjula ( 2001 ) correlation is unchanged : it should be increasingly accurate _ for smaller values _ of @xmath14 . we may interpolate between these extremes by positing : @xmath36^{1/3 } + [ e_\gamma^{\rm iso}/e_0^{\rm iso}]^{2/3}\right\ } \ ; , \label{epi}\ ] ] an expression with two parameters ( @xmath37 , @xmath38 ) ; like the correlation @xmath39^b$ ] ( see , e.g. , amati 2006a , b , c ) , whose power behaviour is arbitrary . a fit to eq . ( [ epi ] ) is shown in fig . the variances around the mean trends of all the correlations we study have roughly log - normal distributions . thus our fits are to the logarithms of the observed quantities . the number fluence of a grb is proportional to @xmath40 , its energy fluence to @xmath41 . the individual - photon energies are @xmath42 . all these facts imply that one expects most observed events to correspond to small @xmath10 ( though obviously not to @xmath43 , a set of null solid angle ) . small @xmath10 means large @xmath16 and @xmath14 , approximately related by @xmath44^{2/3}$ ] . the expectation is supported by the data in fig . these comments on the @xmath26 $ ] correlation and the way it is derived are extensible to the other correlations we shall discuss , e.g. , to the @xmath45 $ ] correlation predicted and tested in dar & de rjula ( 2001 , 2004 ) . given eq . ( [ brief ] ) and in analogy with eq . ( [ epi ] ) , we expect ( dado et al . 2006 ) : @xmath46^{1/4 } + [ ( 1+z)^2\,l_p^{\rm iso}/l_p^0]^{1/2}\right\ } . \label{lpep}\ ] ] this correlation is akin to the one proposed by yonetoku et al . ( 2004 ) , but its power behaviour is not arbitrary . to derive the other correlations we shall confront with data , we must recall the cb - model expectations for pulse rise - times and event variabilities , and derive the one for the lag - time . but eqs . ( [ brief],[tlagv ] ) allow us to anticipate the results : @xmath47^{1\over 4 } + \left[(1+z)^2\,l_p^{\rm iso}/l_p^0\right]^{1\over 2 } \right\}^{-1 } \label{tmineq}\ ] ] @xmath48^{1\over 4 } + \left[(1+z)^2\,l_p^{\rm iso}/l_p^0\right]^{1\over 2}\right\ } \label{veq}\ ] ] @xmath49^{1\over 2 } + \left[(1+z)^2\,l_p^{\rm iso}/l_p^0\right]^{1 } \right\}^{-1 } \label{tlageq}\ ] ] the predictions of eqs . ( [ epi ] ) to ( [ tlageq ] ) are tested in figs . [ f1 ] and [ f2]a . the data are from schaefer ( 2006 ) ; values of @xmath38 and data for some extra grbs at low @xmath38 and @xmath16 ( which could be classified as x - ray flashes ) are from amati ( 2006a , b , c ) . all results are satisfactory . two observables ( @xmath15 and @xmath50 ) reflect fixed values of @xmath0 and @xmath9 , since they refer to a particular pulse in a grb light curve , not necessarily the same one . for multi - pulse grbs , the other observables reflect averages over the various pulses . single - peak correlations should be tighter than the ones we have discussed , but properly analized data are not available . we also expect correlations between two multi - pulse - averaged observables to be tighter than those between a multi - pulse observable and a single - pulse one . the only correlation of the former type in figs . [ f1 ] and [ f2 ] is that between @xmath16 and @xmath14 in fig . [ f1]a ; it is indeed the tightest . the correlations we have discussed are not the simplest ones the cb model suggests . indeed , it follows from eqs . ( [ brief],[tlagv ] ) that : @xmath51^{3/4},\;\;\;\;\ ; v\propto e_p,\;\;\;\;\ ; t_{\rm rise } \propto e_p^{-1}. \label{simple}\ ] ] these relations involve just one parameter : the proportionality factor , and deserve to be studied , even if they add no significance to the results , for they are redundant with the correlations we have already discussed . the first two predictions in eqs . ( [ simple ] ) are shown in figs . [ f2]b , c . the correlations of @xmath20 and @xmath52 with @xmath16 are less informative , not only because the first two of these observables are of a somewhat debatable significance , but because the dynamical ranges of @xmath20 , @xmath52 and @xmath16 span @xmath53 orders of magnitude , while the data on @xmath15 , @xmath14 and @xmath21 span @xmath54 times as many . in the cb model there are two a priori time scales determining the rise - time and duration of a pulse : the time it takes a cb to expand to the point at which it becomes transparent to radiation and the time it takes it to travel to a distance from which the remaining of its path is transparent to @xmath0 rays ( dar & de rjula 2004 ) . these two times are , for typical parameters , of the same order of magnitude . we discuss the second time scale here , for it is the one naturally leading to larger variabilities and differences in rise - time . the @xmath0 rays of a grb s pulse must traverse the pre - sn wind material remaining upstream of their production point , at a typical distance of @xmath55 from the parent sn . at these ` short ' distances , the observed circumburst material is located in layers whose density decreases roughly as @xmath56 and whose typical @xmath57 is large : @xmath58 ( chugai et al . 2003 ; chugai & danzinger 2003 ) . compton absorption in such a wind implies that a pulse of a grb initially rises with time as @xmath59 $ ] , where ( dar & de rjula 2004 ) : @xmath60 the values of @xmath61 may differ for the different cbs ( pulses ) of a grb even if they are emitted in precisely the same direction , which need not be the case , e.g. if the emission axis precesses . the minimum rise - time , @xmath17 , used as a variability measure in schaefer ( 2006 ) , satisfies eq . ( [ twtrans22 ] ) , and was used in fig . [ f1]c . the result in eq . ( [ twtrans22 ] ) is for an ideal spherically - symmetric wind . actual wind distributions are layered and patchy , implying an in - homogeneous distribution of the glory s light density . since the number of photons compton up - scattered by the cb is proportional to this density , the inhomogeneities would directly translate into a variability on top of a smooth pulse shape , which reflects the average density distribution of the wind - fed medium . this corresponds to a source of variability that , as a function of @xmath9 , @xmath0 and @xmath12 , behaves as the inverse of @xmath62 , the form used for @xmath20 in eq . ( [ brief ] ) and fig . [ f1]d ( in the cb model , the deviations from a smooth behaviour observed in some optical and x - ray ags also trace the inhomogeneities in the density of the interstellar medium ; see dado et al . 2003a , 2006 ) . there are many ways to define the variability of a grb ; variations of the sort we have described are the ones studied by schaefer ( 2006 ) . the data in figs . [ f1]c , d are from his analysis and definitions . in the cb model a pulse s @xmath0-ray number flux as a function of energy and time is of the form ( dar & de rjula , 2004 ) : @xmath63 the function @xmath64 is well approximated by @xmath59\,\{[1-{\rm exp}[-(t^w_{tr}/t)^2]\}$ ] , with @xmath62 as in eq . ( [ twtrans22 ] ) . the predicted shape of @xmath65 is amazingly similar to that of ` band s ' phenomenological spectrum and has a weak time - dependence that makes the spectrum within a pulse soften with time , in a time of order @xmath62 . the energies @xmath66 in @xmath65 scale with @xmath67 : @xmath68 where @xmath69 is the angle of incidence of a glory s photon onto the cb ( in the sn rest system ) and @xmath70 is the pseudo - temperature in the thin thermal - bresstrahlung spectrum @xmath71/e_i$ ] of the glory s light . we conclude that @xmath72 with @xmath73 a predicted function . this implies that @xmath74 with @xmath75 a slowly - varying function of @xmath76 ( a fact that can be traced back to the time dependence of @xmath65 being much slower than that of @xmath64 ) . let @xmath77 be the rise - time of a pulse at a given @xmath0-ray energy @xmath78 . the lagtime is defined and approximated as : @xmath79 where @xmath80 is generally taken to be a fixed energy interval between two ` channels ' in a given detector . use eqs . ( [ tpformula ] , [ tlagdef ] ) to deduce that : @xmath81 where , on dimensional grounds , we used @xmath82 . it follows from eqs . ( [ teff],[twtrans22 ] ) that : @xmath83 the result announced in eq . ( [ tlagv ] ) and used in fig . some correlations do not follow from comparisons of @xmath0 and @xmath9 dependences . one of them ( dar & de rjula 2004 ) is the following . as the cb reaches the more transparent outskirts of the wind , its ambient light becomes increasingly radially directed , so that the average @xmath84 in eq . ( [ teff ] ) will tend to @xmath85 as @xmath86 . since the ( exponential ) rise of a typical pulse is much faster than its ( power ) decay , the width of a peak is dominated by its late behaviour at @xmath87 . at such times , @xmath88 in eq . ( [ teff ] ) , so that @xmath89 is , approximately , a function of the combination @xmath90 . consequently , the width of a grb pulse in different energy bands is : @xmath91 , in agreement with the observation , @xmath92 , for the average fwhm of peaks as a function of the energies of the four batse channels ( fenimore et al . 1995 , norris et al . 1996 ) . this correlation is shown in fig . the cb model is very successful in its description of all properties of the pulses of long - duration grbs ( dar & de rjula 2004 ) . we have extended our previous discussions of one of these properties : the correlations between pairs of observables . we have analyzed a wealth of newly available data and derived predictions for some observables which we had not studied before . although our predictions are expected to be better satisfied for individual pulses , the results are very satisfactory even when applied to entire grbs : all of the predicted trends agree with the observations . the correlations we have discussed have a common and simple physical basis : relativistic kinematics and compton scattering . the viewing angle @xmath10 is the most crucial parameter underlying the correlations , and determining the properties of grbs and their larger-@xmath10 counterparts , x - ray flashes ( dar & de rjula 2004 , dado et al . . * acknowledgements . * this research was supported in part by the helen asher space research fund and the institute for theoretical physics at the technion institute . adr thanks the institute for its hospitality . in this appendix , and in the example of the @xmath93 $ ] correlation , we prove in detail the double - power " nature of many of the correlations predicted by the cb model . for a typical angle of incidence ( dar & de rjula 2004 ) , the energy of a compton up - scattered photon from the sn glory is lorentz and doppler boosted by a factor @xmath94 and redshifted by @xmath95 . the peak energy @xmath16 of the grb s @xmath0-rays is related to the peak energy , @xmath96 ev , of the glory s light by : @xmath97 the spherical equivalent energy , @xmath14 , is ( dar & de rjula 2004 , dado et al . 2006b ) : @xmath98 where @xmath99 is the mean sn optical luminosity just prior to the ejection of cbs , @xmath100 is the number of cbs in the jet , @xmath101 is their mean baryon number , @xmath102 is the comoving early expansion velocity of a cb ( in units of @xmath103 ) , and @xmath104 is the thomson cross section . the early sn luminosity required to produce the mean isotropic energy , @xmath105 erg , of ordinary long grbs is @xmath106 , the estimated early luminosity of sn1998bw . the explicit proportionality factors in the relations @xmath107 and @xmath28 are given by eqs . ( [ eobs],[eiso ] ) . let us first consider them fixed at their typical values . the typical @xmath108 $ ] domain of observable grbs is then the one shown in fig . the observed values of @xmath0 are fairly narrowly distributed around @xmath109 ( dado et al . 2003a , dar & de rjula , 2004 ) , as in the blue strip of the figure . the @xmath108 $ ] domain is also limited by a minimum observable isotropic energy or fluence ( both @xmath110 ) , by a minimum observable peak energy , and by the line @xmath111 or , if one takes into account that phase space for observability diminishes as @xmath112 , by a line corresponding to a minimum fixed @xmath10 . the elliptical sweet spot " in fig . [ f3]a is the region wherein grbs are most easily detectable , particularly in pre - swift times . in the cm model x - ray flashes are grbs seen at a relatively large @xmath113 ( dar & de rjula , 2004 , dado et al . 2004 ) they populate the region labeled xrf in the figure , above the fixed @xmath114 line or to the left of the fixed @xmath16 line . the blue line in fig . [ f3]d is the contour of the blue domain of fig . [ f3]a , shown in the @xmath115 $ ] plane of the @xmath93 $ ] correlation . at low values of these quantities , the correlation is @xmath116 . at the opposite extreme , the expected power is half - way between 1/3 and 2/3 . but there is another effect increasing this expectation to @xmath117 . a cb that is expanding , in its rest system , at a speed of relativistic sound ( @xmath118 ) or at the speed of light ( @xmath119) subtends a non - vanishing angle from its point of emission . in the sn rest system , this ( half-)angle is @xmath120 . at a fixed observer s angle , @xmath10 , the value of @xmath9 and @xmath41 entering eqs . ( [ eobs],[eiso ] ) are not the naive " ones of eq . ( [ delta ] ) , but are averages , @xmath121 and @xmath122 , over the cb s non - vanishing surface . in fig . [ f3]b we show function @xmath123 , for fixed @xmath0 and @xmath124 ( the result is very similar for @xmath125 ) . this figure is easy to interpret : for @xmath126 , the cb is effectively point - like and @xmath127 . at the opposite extreme , @xmath128 , the observer s angle is immaterial and @xmath129 . the consequences of this fact on the @xmath93 $ ] correlation can be seen in fig . [ f3]c , where we have plotted @xmath130 versus @xmath131 , at fixed @xmath0 . the @xmath132 functional dependence smoothly evolves from a 1/3 to a 2/3 power . we plot in fig . [ f3]d , as the banana - like dashed line , the border of the blue domain of fig . [ f3]a , taking into account the geometrical effect we just described . the result is an @xmath93 $ ] correlation with an index varying from 1/3 to @xmath117 . finally , we may consider the effect of varying the proportionality factors in eqs . ( [ eobs],[eiso ] ) around their reference values . this results in a superposition of banana - like domains , the general behaviour of which we have approximated by the @xmath93 $ ] correlation of eq . ( [ epi ] ) . similar considerations apply to all the other two - power correlations that we have studied .

several pairs of observable properties of gamma ray bursts ( grbs ) are known to be correlated . many such correlations are straightforward predictions of the ` cannonball ' model of grbs . we extend our previous discussions of the subject to a wealth of new data , and to correlations between ` lag - time ' , ` variability ' and ` minimum rise - time ' , with other observables . schaefer s recent systematic analysis of the observations of many grbs of known red - shift gives us a good and updated data - basis for our study . -1 cm

it is well known that bose - einstein condensates ( becs ) with weak attractive interactions between atoms can form stable solitons in cigar - shaped " ( nearly one - dimensional , 1d ) traps . in these traps , the gas is strongly bound in the transverse plane , while being loosely confined along the longitudinal axis ( @xmath0 ) . using this configuration , stable bright solitons were created in the gas of @xmath1li atoms @xcite . in the condensate of @xmath2rb atoms trapped in a similar configuration , stronger attraction between atoms leads to collapse and emergence of nearly 3d solitons in a _ post - collapse _ state @xcite . the strongly elongated ( cigar - shaped ) settings are described by effectively 1d equations which were derived , by dint of various approximations , from the full 3d gross - pitaevskii equation ( gpe ) @xcite-@xcite . the derivation assumes an _ ansatz _ factorizing the 3d wave function into a product of a transverse mode and an axial ( one - dimensional ) wave function . as shown in refs . @xcite , the substitution of the factorized ansatz in the underlying cubic gpe leads , in the general situation , to a _ nonpolynomial schrdinger equation _ ( npse ) for the axial wave function ( or a system of coupled npses for a two - component bec @xcite ) . in the case of weak nonlinearity , the npse can be expanded , which leads to a simplified 1d equation with a combination of cubic and quintic terms , the latter one being always _ attractive _ ; if the cubic term is attractive too , the cubic - quintic equation gives rise to a family of stable solitons available in an exact analytical form @xcite . unlike the ordinary 1d nonlinear schrdinger ( nls ) equation with the attractive cubic term , the npse , as well as its cubic - quintic truncation , may give rise to collapse , which reflects the occurrence of the collapse in the underlying cubic gpe in three dimensions @xcite . despite the possibility of the collapse , solitons are stable in these models . a relevant problem is to derive the npse for the cigar - shaped trap equipped with a periodic potential , which is created in the experiment as an _ optical lattice _ ( ol ) , i.e. , an interferences pattern , by a pair of counterpropagating laser beams illuminating the trap in the axial direction ( the bec dynamics in periodic potentials was recently reviewed in ref . markus ) . a 1d equation of the npse type including the ol potential was recently derived in ref . @xcite . using that equation , the influence of the periodic potential on the collapse threshold for axially localized states in the quasi-1d trap was investigated , both for single - peak solitons found in the semi - infinite gap of the periodic potential , and multi - peaked solitons found in finite bandgaps . the results were compared to direct numerical solutions of the full 3d gpe , showing good agreement . in the experiment , the transverse potential which confines the atomic gas to the cigar - shaped configuration may be axially nonuniform , which corresponds to the corresponding trapping frequency being a function of the axial coordinate , @xmath3 ( generally speaking , it may also depend on time ) . as proposed in ref . @xcite , a specially designed nonuniformity ( _ axial modulation _ ) of @xmath4 may be used as an alternative tool for the control of dynamics of nearly 1d solitons , inducing an effective potential for them . in that work , the effective potential for a soliton with norm ( scaled number of atoms ) @xmath5 was found in the limit of weak nonlinearity and long - scale axial modulation , @xmath6where @xmath7 is an effective nonlinearity coefficient , see eq . ( [ efun ] ) below ( we will use normalization tantamount to setting @xmath8 ) , @xmath9 is the coordinate of the soliton s center , and integer @xmath10 is possible _ intrinsic vorticity _ of the quasi-1d soliton , which is defined below in eq . ( [ s ] ) ( ordinary solitons correspond to @xmath11 ) . expression ( [ eff ] ) was derived by means of a variational approximation ( va ) applied directly to the full 3d energy functional , cf . ( [ e - npse ] ) below . of special interest is the case of periodic modulation of the transverse trapping frequency , with wavenumber @xmath12 , modulation depth @xmath13 , and amplitude @xmath14 : @xmath15 . \label{u}\]]as suggested by eq . ( [ eff ] ) , the periodic modulation may replace the ol potential . in particular , this setting may be especially relevant to a situation when the quasi-1d magnetic trap is not rectilinear , but rather circular ( toroidal ) , which was realized in the experiment @xcite . indeed , the ol can not be created in such a setting , but the induction of an effective periodic potential by means of the modulation of the transverse trapping frequency is quite feasible . the objective of the present work is to derive an effective npse for the quasi-1d trap subject to the periodic modulation as per eq . ( [ u ] ) , and to investigate various self - trapped states in this geometry , both delocalized ones and solitons . the paper is organized as follows . the npse is derived , in a general form , in sec . then , the model with the repulsive nonlinearity is considered in sec . iii . at first , the analysis includes an additional parabolic trapping potential acting in the axial direction . then , this potential is removed , and we analyze solutions demonstrating a transition from delocalized solutions to a gap soliton . the solutions predicted by the effective 1d equation are compared to their counterparts found from the full 3d gpe ( bandgap structures generated by linearized versions of both equations are compared too ) . section iv is dealing with the case of the attractive nonlinearity . the corresponding ground - state solitons are found by means of the va and in a numerical form , which are also compared with results produced by the full 3d equations . because the attractive nonlinearity may give rise to collapse , the collapse threshold is considered in detail too , by means of both the va and numerical methods . in addition to the ground - state solitons , which reside in the semi - infinite gap induced by periodic modulation ( [ u ] ) , we also explore solutions with the chemical potential belonging to the first finite gap , and demonstrate the transition from delocalized states to gap solitons in that case . the paper is concluded by sec static bec configurations can be derived from the normalized functional which determines the energy - per - atom in terms of order parameter ( single - atom wave function ) @xmath16 and includes a generic external axial potential @xmath17 : @xmath18 ( x^{2}+y^{2})\right.\]]@xmath19 \psi ( \mathbf{r } ) . \label{efun}\]]here @xmath20 is the adimensional strength of the interaction between atoms , with @xmath21 the inter - atomic scattering length and @xmath5 the number of atoms in the condensate . in eq . ( [ efun ] ) lengths are measured in units of the characteristic transverse trapping ( harmonic - oscillator ) length , @xmath22 , where @xmath23 is the atomic mass , the energy is in units of @xmath24 , modulation wave number @xmath12 is in units of @xmath25 , and the wave function is subject to the ordinary normalization , @xmath26the chemical potential corresponding to eqs . ( [ efun ] ) and ( [ n ] ) is @xmath27due to the above normalizations , @xmath14 and @xmath5 are not explicitly present in expressions ( [ efun ] ) and ( [ mu ] ) . an accurate investigation of the present setting can be performed by using the approach which was first developed for the gpe with the unmodulated transverse trap ; after averaging the full 3d equation in the transverse plane , it leads to an effective one - dimensional npse @xcite . the derivation of the npse starts with the factorization of the 3d wave function into a product of an arbitrary complex axial wave function , @xmath28 , and the ordinary transverse gaussian _ ansatz _ with transverse width @xmath29 , @xmath30@xmath28 being subject to normalization condition @xmath31 configurations including the above - mentioned intrinsic vorticity , characterized by positive integer @xmath10 , correspond to the following generalization of eq . ( [ factor]):@xmath32where @xmath33 and @xmath34 are the polar coordinates in transverse plane @xmath35 . nearly-1d solitons with intrinsic vorticity were studied , by means of methods similar to those used in the present work ( although without deriving a closed - form npse for that case ) in ref . @xcite ; for a limit case of a strongly elongated 3d trap , similar localized states were also studied in ref . @xcite . in this work , we focus on the ordinary solitons , with @xmath11 . inserting expression ( [ factor ] ) in eq . ( [ efun ] ) , one obtains , neglecting the @xmath0-derivative of @xmath36 , the following effective ( 1d ) energy functional : @xmath37@xmath38 \sigma ^{2}(z)\right ) + { \frac{1}{2}}{\frac{\gamma } { \sigma ^{2}(z)}}|f(z)|^{2}\right\ } f(z)~. \label{e - npse}\]]the minimization of this functional with respect to @xmath28 , taking normalization ( [ n1d ] ) into regard , leads to the stationary npse , @xmath39 \sigma ^{2}(z)\right ) \right.\]]@xmath40 f=\mu \,f . \label{npse}\]]where the chemical potential @xmath41 appears as the lagrange multiplier generated by the normalization condition . an equation for the transverse width is obtained by the minimization of functional ( [ e - npse ] ) with respect to @xmath42:@xmath43the substitution of this expression in eq . ( [ npse ] ) leads to a closed - form stationary npse for @xmath28 , although in a rather cumbersome form . in the limit of zero scattering length , @xmath44 , eqs . ( [ npse ] ) and ( [ sigma - npse ] ) reduce to the linear schrdinger equation , @xmath45 f(z)=\mu f(z ) , \label{npse - g0}\]]with the effective axial potential , @xmath46(note that , even in this limit , the full 3d gpe is not separable , due to the modulation imposed on the transverse trapping potential ) . if the nonlinear term @xmath47 is small , the npse may be approximated by the cubic nls equation with the same effective axial potential and , in addition to that , with a periodically - modulated nonlinearity coefficient : @xmath48@xmath49 f(z)=\mu f(z ) . \label{nls}\]]essentially the same result as given by eq . ( [ nls ] ) was obtained , in the simplest approximation , in ref . @xcite , see eqs . ( [ eff ] ) and ( [ u ] ) . in the case of the repulsive inter - atomic interaction , i.e. , positive @xmath21 and @xmath7 , the application of the thomas - fermi ( tf ) approximation , which neglects the second derivative , to eqs . ( [ npse ] ) and ( [ sigma - npse ] ) yields an analytical expression for the normalized atomic density , @xmath50 : @xmath51 , \label{figata}\]]where an effective local chemical potential is @xmath52equations ( [ figata ] ) and ( [ figata1 ] ) generalize the result obtained in ref . @xcite for the repulsive bec under the unmodulated transverse confinement ( @xmath53 ) . in the limit case of strong nonlinearity , @xmath54 , eq . ( [ figata ] ) reduces to @xmath55and in the opposite limit of @xmath56 , which implies @xmath57 , it takes the form @xmath58 . to obtain accurate results , we solved the time - dependent variety of eq . ( npse ) ( with @xmath41 replaced by @xmath59 and , accordingly , @xmath60 replaced by @xmath61 ) , combined with eq . ( sigma - npse ) ( without any change in the latter equation ) numerically , by means of the finite - difference crank - nicholson method in imaginary time , following the approach elaborated in ref . the explicit axial potential was chosen in the usual form , @xmath62 , where @xmath63 , and @xmath64 is the axial - confinement frequency . in this way , the profiles for @xmath65 , displayed by dashed lines in fig . 1 , have been obtained for different values of modulation depth @xmath66 and fixed nonlinearity strength , @xmath67 . the so obtained npse profiles are compared to those produced by the tf approximation ( dotted lines in fig . 1 ) , see eq . ( figata ) . in the absence of transverse modulation , @xmath53 ( the upper panel in fig . 1 ) , the axial density profile is well approximated by the tf formula . at @xmath68 ( the central and lower panels in fig . 1 ) , the tf approximation much overestimates the density contrast between points of local minima and maxima of the total axial potential . in the self - repulsive bec with @xmath69 , @xmath70 , @xmath71 , at different values of the modulation amplitude @xmath72 . solid lines : results obtained from the full three - dimensional gpe , derived by the minimization of the underlying energy functional , which is given by eq . ( [ efun ] ) . dashed lines : the profiles produced by the numerical solution of the one - dimensional _ nonpolynomial schrdinger equation _ ( npse ) , eq . ( [ npse ] ) . dotted lines : results obtained from the thomas - fermi approximation applied to the npse , i.e. eq . ( [ figata ] ) . when using the 3d equation , in this figure and below , the axial density displayed in the plots is defined by integration in the transverse plane , @xmath73 , while in other cases it is simply @xmath74.,title="fig:",height=288 ] it is necessary to compare results produced by the npse to their counterparts found from a direct numerical solution of the full gpe in three dimensions . the latter equation is obtained by the minimization of energy functional ( [ efun ] ) . figure 1 shows that the density profiles generated by the npse ( dashed lines ) are very close to ones obtained from the 3d equation ( solid lines ) , unless @xmath66 is very large . it is noteworthy that the npse gives very accurate results for a model with non - separable potential . one may expect that the effective axial periodic potential induced by the transverse modulation ( without the inclusion of the axial parabolic trap ) may support quasi - periodic bloch states and _ gap solitons _ in the self - repulsive bec , as in the case of the ordinary ( direct ) periodic potential @xcite . to consider this possibility , a self - consistent numerical method was used , with periodic boundary conditions . we employed a spatial grid of @xmath75 points , covering the interval of @xmath76 , which corresponds to @xmath77 periods of the external modulation . to test the numerical scheme , we have checked that the lowest - energy state in the semi - infinite bandgap ( i.e. , the ground state of the system ) , produced by this method , is identical to that found above by the integration of the time - dependent npse in imaginary time . in the upper panel of fig . 2 we plot , as a function of nonlinearity strength @xmath7 , the first @xmath78 eigenvalues @xmath79 , as found by means of the above - mentioned numerical method from eqs . ( [ npse ] ) and ( [ sigma - npse ] ) with @xmath80 and periodic boundary conditions . the lowest @xmath77 eigenstates @xmath81 belong to the first _ nonlinear _ band induced by the periodic modulation in the full npse , and the other states , which are well separated by a _ bandgap _ , form a second nonlinear band . for some of the intraband states , the numerical method does not converge to a single configuration , but rather oscillates between two or three configurations with very close eigenvalues . it is also possible that the nonlinear model may give rise to intraband states which have no counterparts in the linear limit . this challenging issue needs special treatment , and will be considered elsewhere . as concerns the nonlinear eigenstates for which our presently employed numerical method leads to convergence ( including the gap soliton , see below ) , we have verified , by direct simulations of the time - dependent npse in real time , that they _ all _ are stable . eigenvalues @xmath82 found from the npse , eq . ( [ npse ] ) , with @xmath80 , @xmath83 and @xmath71 , as functions of nonlinearity parameter @xmath84 . lower panel : the axial density profile , @xmath85 , of the 32th eigenfunction , at @xmath83 , for three values of @xmath86 . the figure shows that the 32th eigenstate becomes a _ gap soliton _ at sufficiently large @xmath84.,title="fig:",height=268 ] as a typical example , in the lower panel of fig . 2 we plot the density profile of the 32th state ( it has number @xmath77 in the set of @xmath78 numerically found states ) for @xmath87 and three different values of @xmath7 . one can check that , in the linear approximation , this state lies at the top of the first bloch band . with the increase of the nonlinearity strength @xmath88 , the energy of the 32th state grows , and , in doing so , it enters the first finite bandgap ( as defined in the linear approximation ) from below . figure 2 demonstrates that , for @xmath89 , this state is still fully delocalized , being thus similar to a bloch wave , while for @xmath90 it becomes localized , with a width much smaller than the length of the periodic box . clearly , this solution may be identified as a _ gap soliton_. at @xmath91 , the gap soliton compresses itself ( see fig . 2 ) into a still narrower state . it is also necessary to check that the bandgap structure in the npse with the periodically modulated trapping potential in the linear limit ( @xmath92 ) is not , by itself , an artifact of the approximation ( reduction of the 3d equation to the 1d limit ) , but a true feature of the full 3d model . to this end , we solved the eigenvalue problem for the full linear gpe in three dimensions , @xmath93@xmath94 \,\psi ( \rho , z)=\mu _ { j}\,\psi ( \rho , z ) , \label{alce_gpe3d}\]]where @xmath95 acts on @xmath96 and @xmath97 , and , as above , @xmath98 . the transverse part of solutions to eq . ( alce_gpe3d ) may be taken as an eigenstate of the corresponding 2d harmonic oscillator , with its quantum numbers @xmath99 and @xmath100 . defining @xmath101 as the smallest reciprocal lattice vector and writing @xmath102 ( @xmath103 is an integer ) , we find that the solution can be written as @xmath104with coefficients @xmath105 satisfying a linear eigenvalue problem , @xmath106 \,c_{m_{x},m_{y},q+g_{n}}\]]@xmath107where @xmath108 is a wavenumber in the first brillouin zone , and the matrix @xmath109 is @xmath110@xmath111@xmath112 + \delta _ { m_{y},m_{y}^{\prime } } \label{alce_a}\]]@xmath113@xmath114 \right\ } .\]]we solved eq . ( [ alce_eigenprob ] ) by truncating the sum in expression ( [ alce_bloch_cwf ] ) to @xmath115 . at first , we also truncated the summation to @xmath116 ( i.e. , only the contribution from the ground state of the transverse potential was taken into account ) , which yielded the result shown in the left panel of fig . [ alce_figure ] . then we found more accurate solutions , by extending the truncated summation to @xmath117 ( i.e. , including the contribution from excited transverse states ) . in that case , eq . ( [ alce_eigenprob ] ) produces the dispersion relation shown in the right panel of fig . [ alce_figure ] . ) , and from the effective 1d equation , eq . ( [ npse ] ) , for @xmath71 , @xmath83 and @xmath118 . left panel : eq . ( [ alce_eigenprob ] ) was solved by confining the summation to @xmath116 . right panel : the summation range was extended to @xmath117.,height=249 ] these results were compared to the dispersion law as found directly from the npse , eq . ( [ npse ] ) . we observe that the two dispersion laws are identical if the 3d analysis is confined to @xmath116 , while they are different if the effect of states with @xmath119 are considered . nevertheless , fig . [ alce_figure ] shows that the first band , the first gap , and half of the second band do not alter essentially , if the npse is replaced by the full 3d equation , which justifies the use of the npse approximation for values of the chemical potential up to the first half of the second band . the model with the attractive inter - atomic interactions , i.e. @xmath120 , may be expected to generate bright solitons . we analyzed this possibility through the numerical solution of the npse equation , in the absence of the direct axial potential , @xmath80 . in fig . 4 , we plot axial density profiles of the thus found solitons for different values of modulation depth @xmath66 and fixed nonlinearity strength , @xmath121 . for @xmath53 , the soliton s profile , with a single maximum , may be well fitted by @xmath122 , which is an asymptotically exact solution ( the usual nls soliton ) in the above - mentioned weakly nonlinear limit corresponding to @xmath123 , provided that @xmath0 varies on the entire real axis . on the other hand , if @xmath0 belongs to a finite interval , @xmath124 , with periodic boundary conditions , @xmath125 , it is known @xcite that the npse with @xmath53 yields a spatially uniform ground state , @xmath126 , for sufficiently weak nonlinearity , @xmath127 ; the ground state develops a spatial structure at @xmath128 . as shown in fig . 4 , for nonzero @xmath66 the soliton profile features several local maxima and minima due to the action of the effective periodic potential . thus , under such conditions , the bose condensate self - traps into a multi - peaked soliton , which occupies several cells of the periodic modulation . , of the ground - state bright soliton in the attractive model with @xmath129 and @xmath71 , for different values of modulation amplitude @xmath72 . dashed lines : results obtained from the npse , eq . ( [ npse ] ) . solid lines : results obtained from the 3d equation , derived by the minimization of energy functional ( [ efun]).,title="fig:",height=249 ] , of the ground - state bright soliton in the attractive model with @xmath129 and @xmath83 , for different values of wave number @xmath12 . results obtained from the npse , eq . ( [ npse]).,title="fig:",height=249 ] we also compared the results yielded by the npse with those found from the direct numerical solution of the full gpe in three dimensions . figure 4 shows that the density profiles generated by the npse ( dashed lines ) practically coincide with the ones obtained from the 3d gpe ( solid lines ) , unless @xmath66 is very large . it is also interesting to analyze the behavior of the density profile of the bright soliton as a function of the wavenumber @xmath12 . in fig . 5 we plot the density profile @xmath65 at @xmath129 and @xmath87 , for four values of @xmath12 . the figure shows that , at @xmath130 , the profile is strongly localized within one single site of the effective periodic axial potential : accordingly , we call the corresponding solution a _ single - site soliton _ @xcite , where the npse for the model with attraction and an explicit periodic axial potential was considered ) . at @xmath131 , delocalization of the bright soliton , which occupies more than one site , is observed . we call it a _ multi - site soliton _ ( the distinction between the strongly and weakly localized solitons is also observed in the 1d cubic nls equation with the self - attractive nonlinearity @xcite ) . from the numerical results presented above we see that the profiles of the localized solutions of eq . ( [ npse ] ) both in the single - site ( strong attraction , large values of @xmath132 ) and in the multi - site soliton cases but with a weak transverse modulation ( small values of @xmath133 ) are smooth . this observation suggests that one could achieve some analytical insight into the model with attraction by using a va with the gaussian ansatz ( a review of the va can be found in ref . @xcite ) , @xmath134where @xmath135 and @xmath136 are variational parameters accounting for the transverse and axial width of the bec . inserting this ansatz in eqs . ( efun ) and ( [ mu ] ) , with @xmath80 ( and @xmath137 ) , we obtain the respective expressions for the energy - per - atom functional and chemical potential , @xmath138 \sigma ^{2}-{\frac{g}{2(2\pi ) ^{1/2}}}{\frac{1}{\sigma ^{2}\eta } } \ ; , \label{e}\]]@xmath139next , we minimize the energy , demanding @xmath140 , which yields the variational equations , @xmath141 \sigma ^{4}=1-{\frac{g}{(2\pi ) ^{1/2}\eta } } \ ; , \label{var1}\]]@xmath142which can be easily solved numerically @xcite . the solutions provide for a minimum of the energy only if the curvature of the energy surface , @xmath143 , is positive , i.e. , @xmath144 as concerns the dynamical stability of the solitons against small perturbations , it may be , first of all , estimated by means of the vk criterion @xcite . according to it , a necessary stability condition is @xmath145 ( in the present notation ) , if the soliton family is described by dependence @xmath146 ( note that the vk criterion does not apply to gap solitons in the model with the repulsive nonlinearity , therefore it was not used in the previous section ) . in fig . 6 , we plot axial length @xmath136 and transverse width @xmath135 versus interaction strength @xmath132 for @xmath71 and four different fixed values of modulation parameter @xmath66 . the figure shows that the soliton in the self - attractive bec exists up to a critical value of the nonlinearity strength , @xmath147 . at @xmath148 , the 3d collapse of the nearly-1d soliton occurs , which is a well - known result in the case of @xmath53 perezgarcia98,sala1,sala2 . note that , for @xmath53 , the va predicts @xmath149 , which is somewhat higher than @xmath150 obtained from the numerical solution of the full gpe in three dimensions @xcite . ( dashed lines ) and axial length @xmath151 ( solid lines ) of the quasi-1d bright soliton in the model with attraction , versus the nonlinearity strength , @xmath152 , as predicted by the variational approximation based on ansatz ( [ ansatz ] ) and eqs . ( [ var1 ] ) , ( var2 ) . on the right side , all curves terminate at the critical point , @xmath153 , past which the collapse occurs . the dependences are displayed for @xmath71 and different values of the modulation depth @xmath72.,title="fig:",height=230 ] the axial length of the soliton , @xmath136 , diverges as @xmath132 drops to zero , while the transverse width @xmath135 approaches @xmath154 , actually becoming equal to the above - mentioned harmonic - oscillator length , @xmath155 . on the other hand , as @xmath132 approaches @xmath147 , both @xmath136 and @xmath135 remain finite and smaller than @xmath154 . new results are presented in fig . 6 for @xmath68 ( recall previous works were only dealing with the case of @xmath53 ) . at small @xmath66 , the figure shows only a slight distortion of the curves . a qualitative change is observed at @xmath156 , when there appear two stable branches for both @xmath157 and @xmath158 , the curves for @xmath158 displaying a clear gap . the lower branches of the @xmath158 and @xmath159 dependences exists only in a finite interval , which we denote as @xmath160 while the upper branches extend up to @xmath161 , in interval @xmath162 , with @xmath163 . physically , the lower branches ( with smaller values of axial length @xmath164 ) correspond to single - site solutions , where the self - attractive bec is strongly localized essentially , within a single cell of the modulation structure . the upper branches of @xmath158 and @xmath159 correspond instead to the weakly localized solutions ( with a larger axial length ) , which occupy several cells ( sites ) . analysis of expressions ( [ e ] ) and ( [ mue ] ) demonstrates that , in interval ( [ existence ] ) , the multi - site and single - site solution may assume the role of ground state ( the one corresponding to the lowest energy ) . however , this analysis also suggests that both families are _ dynamically stable _ , as they always meet the vk criterion , @xmath145 . direct numerical simulations ( not shown in detail here ) have confirmed this conjecture . for @xmath165 , the numerical solution of eqs . ( [ var1 ] ) and ( var2 ) demonstrates that the lower border of existence interval ( existence ) for the single - site soliton , @xmath166 , vanishes , but this is an artifact of the va , which occurs in other contexts too @xcite . it is explained by the above - mentioned inadequacy of the gaussian ansatz in the limit of weak nonlinearity , i.e. , for widely spread small - amplitude solitons featuring a multi - peaked shape . in this situation , one may , in principle , apply a more sophisticated ansatz , combining the gaussian and periodic functions , such as @xmath167 ; however , the generalized ansatz results in a cumbersome algebra @xcite , therefore we do not pursue such an approach here . in the upper panel of fig . 7 , we plot the density profile , @xmath65 , of the soliton for different values of the self - attraction strength , @xmath132 , and fixed modulation parameters , @xmath168 and @xmath71 . as seen in the figure , the increase of @xmath132 may strongly compress the soliton in the axial direction , making the secondary maxima very small . in this case , the condensate actually self - traps into a single - peak soliton , which occupies only one cell of the modulation structure . , of the soliton in the attractive model , with @xmath169 and @xmath71 , obtained for different values of the self - attraction strength @xmath132 from the numerical solution of the npse , eq . ( [ npse ] ) . lower panel : axial length of the soliton , @xmath170 , as a function of @xmath132 , for @xmath169 and @xmath71 . the lower panel includes results provided by the variational approximation based on the gaussian ansatz , see eqs . ( [ var1 ] ) and ( [ var2 ] ) , and those obtained from the numerical solution of the npse.,title="fig:",height=259 ] contrary to the numerical solution of the npse which shows a smooth crossover between multi - site and single - site solitons , the va predicts a discontinuous transition . in the lower panel of fig . 7 , we plot the axial length , @xmath171 , of the ground - state bright soliton as a function of strength @xmath132 , for @xmath168 and @xmath71 . the jump predicted by the variational calculation at @xmath172 , is a consequence of the inadequacy of of ansatz ( [ ansatz ] ) , which assumes the simple gaussian waveform for the axial wave function , to describe multi - peaked states , as was also recently shown in the study of the quasi-1d model with the self - attraction and axial optical lattice @xcite . as it is well known , cold bose atoms with attractive interactions collapse if the interaction strength exceeds a threshold value , @xmath147 . obviously , as @xmath132 increases towards @xmath173 , the profile becomes narrower and narrower , and therefore close to collapse in the presence of a transverse modulation , its shape should correspond to a single - site soliton , where the va is appropriate . it is thus interesting to predict the collapse threshold , @xmath147 , as a function of parameters @xmath133 and @xmath12 of the transverse modulation by using our gaussian variational ansatz . in fig . 8 , we display the dependence @xmath174 predicted by the va at five fixed values of modulation depth @xmath66 . for given @xmath66 , the critical value @xmath175 has its maximum at @xmath176 , which is natural , as eq . ( [ u ] ) yields , in this case , the smallest constant value of the transverse - trapping frequency . equation ( [ u ] ) also helps to understand another feature observed in fig . viz_. , that @xmath147 slowly diverges at @xmath176 as @xmath66 approaches @xmath154 ( for instance , @xmath177 at @xmath178 ) . note also that there exists a modulation wavenumber , @xmath179 , at which @xmath147 attains its _ minimum _ , i.e. , the collapse has the lowest threshold . figure 8 shows that this minimum decreases with the increase of @xmath66 , which may be understood too : as mentioned above , the strong potential tends to squeeze the entire condensate into a single cell of the modulation structure , which facilitates the onset of the collapse . on the other hand , at large values of @xmath12 , @xmath147 becomes asymptotically constant , as the interaction of the condensate with the short - period modulation becomes exponentially weak , hence it produces little effect on the collapse threshold . for the collapse of the quasi-1d soliton in the model with attraction versus modulation wave number @xmath12 , as predicted by the variational approximation . the dependences are displayed at fixed values of modulation depth @xmath72.,title="fig:",height=230 ] in table 1 , we display the comparison of the va - predicted critical value , @xmath147 , to results following from the numerical solution of npse ( [ npse ] ) ( for @xmath168 ) . the variational and numerically found critical values are seen to be in qualitative agreement . note that , at @xmath176 , the critical value for the npse is @xmath180 , which is an obvious extension of @xmath181 found before at @xmath53 sala1,sala2 . 0.3 cm [ cols="^,^,^,^,^",options="header " , ] table 1 . properties of the bright soliton in the model with attraction in a proximity to the collapse , as found from the numerical solution of eq . ( [ npse ] ) at @xmath168 and different values of modulation wavenumber @xmath12 : @xmath147 is the critical value of the nonlinearity coefficient at the collapse point , @xmath182 is the axial width of the soliton , and @xmath183 its transverse width ( at @xmath184 ) at the same critical point . for comparison , also included are values of @xmath147 predicted by the variational approximation , @xmath185 . 0.3 cm table 1 demonstrates that , with the increase of @xmath12 , the critical value , @xmath147 , drops from the largest value , corresponding to @xmath176 , to a minimum at @xmath186 , and then slightly increases with the further increase of @xmath12 ( the minimum at @xmath186 seems quite shallow from the side of @xmath187 ) . this feature and the related ones can be explained if one notices that @xmath176 corresponds to a constant value of the modulation factor in eqs . ( [ npse ] ) and ( sigma - npse ) , @xmath188and , on the other hand , for large @xmath12 ( formally , for @xmath189 ) , the modulation factor should be replaced by its average , @xmath190where @xmath191 is the complete elliptic integral of the second kind . then , eqs . ( [ npse ] ) and ( [ sigma - npse ] ) with the constant modulation factor @xmath192 ( and without the extra potential , @xmath193 ) , take the form of@xmath194@xmath195 f=\frac{\mu } { \beta } \,f \label{beta}\]](recall @xmath121 ) . further , the coefficient @xmath196 can be eliminated from eq . ( [ beta ] ) by means of an obvious rescaling [ which also takes into regard the condition that the normalization of the solution must keep the form of eq . ( [ n1d])]:@xmath197as a consequence , the critical values of @xmath132 , together with the respective length scale , which correspond to the different constant values of @xmath192 , are related as follows:@xmath198for @xmath168 ( the value for which numerical data are collected in table 1 ) , eqs . ( [ k=0 ] ) and ( [ k = infinity ] ) yield @xmath199 @xmath200 and @xmath201 , hence the ratios predicted by eq . ( [ ratio ] ) take the value @xmath202 . on the other hand , the numerical data from table 1 yield @xmath203 , and @xmath204 @xmath205 . thus , approximating @xmath147 at @xmath186 by @xmath206 ( recall the change of @xmath147 at @xmath187 is insignificant ) , one can explain ( at least , in a crude approximation ) effects caused by the transition from long - scale to short - scale spatial modulation . the above analysis was dealing with solitons ( in the attractive model ) whose chemical potential belongs to the semi - infinite bandgap in the linear spectrum of eq . ( [ npse ] ) . on the other hand , it is known that the cubic self - attractive nonlinearity may also give rise to solitons located in higher - order ( finite ) bandgaps . here , we report soliton solutions of the latter type , found from the npse by means of the self - consistent numerical method with periodic boundary conditions , which was outlined in the previous section . in fig . 9 we plot the first @xmath78 eigenvalues @xmath79 , as found from the numerical solution of the stationary nonlinear npse , versus the nonlinearity strength @xmath132 . the first @xmath77 eigenstates form the first band , and the other @xmath207 , which are well separated by a gap , cluster into the second band . figure 9 shows that the lowest eigenvalue and the 33rd one split off from the first and second bands and move down ( till the onset of the collapse ) with the increase of @xmath132 , thus giving rise to localized states in the semi - infinite and first finite gaps , respectively . it is worthy to note that the second eigenvalue , which originally belonged to the first band , also splits off from it at larger values of @xmath132 . we have verified that the corresponding nonlinear eigenstate become localized , as one may expect . qualitatively similar findings were reported in ref . @xcite , which was dealing with a numerical solution of the ordinary cubic gpe in one dimension , and , more recently , in ref . @xcite which was dealing with the self - attractive bec in the quasi-1d trap with an axial ol potential . found from the numerical solution of npse , eq . ( [ npse ] ) , with @xmath83 and @xmath71 , as functions of the nonlinearity strength in the model with attraction , @xmath208.,title="fig:",height=230 ] the density profiles , @xmath209 , of the 33th state which develops into a soliton belonging to the first finite bandgap , are displayed , for @xmath87 and six different values of interaction strength @xmath132 , in fig . the figure shows that this state is still fully delocalized ( being similar to a bloch wave ) at @xmath210 , while at @xmath211 it becomes localized , with the width much smaller than the length of the periodic box , featuring many local maxima and minima ( zeros ) . with further increase of @xmath132 , the gap soliton keeps compressing itself . comparing figs . 4 and 10 , we conclude that the ground - state solitons , which reside in the semi - infinite gap , are drastically different from the _ gap solitons _ , i.e. , ones found in the first finite bandgap . first , for the same parameters , the ground - state solitons are localized much stronger , and their local density minima are not zeros , unlike those of the gap solitons . in addition , it is noteworthy that local density maxima of the ground - state solitons correspond to minima of the effective periodic potential , while the local maxima of the gap soliton correspond to _ maxima _ of the periodic potential . , of the 33th nonlinear eigenfunction of the npse ( which develops from a bloch - like delocalized state into a gap soliton ) for @xmath83 , @xmath71 and six values of @xmath132.,title="fig:",height=220 ] although the gap solitons can not play the role of ground states , they , as well as the ground - state solitons , are stable in direct simulations of the time - dependent variant of the npse equation . therefore , the gap - soliton states are relevant to the experiment . in this work , we have derived the effective one - dimensional npse ( nonpolynomial schrdinger equation ) for a cigar - shaped trap whose transverse confining frequency is periodically modulated along the axial direction , thus inducing an effective periodic axial potential . besides the usual quasi-1d linear geometry , the model may also be relevant as a means of creating an effective periodic potential in toroidal traps . in both cases of the repulsive and attractive nonlinearity , delocalized states and solitons were found , by means of numerical methods ( which were applied to both the effective npse and the underlying 3d gross - pitaevskii equation ) and va ( variational approximation ; this method was applied to ground - state solitons in the model with attraction , and to the prediction of the collapse threshold in this case ) . it was found that the numerical solution to the npse is always extremely close to the full 3d solutions . the va yields quite reasonable results too , except for the description of the crossover from single - site to multi - site solitons : numerical results reveal that the crossover is smooth and does not include a jump , contrary to the prediction of the va . this shortcoming of the va is explained by the fact that the simple gaussian ansatz , on which the approximation is based , can not adequately grasp the transition that alters the shape of the soliton , giving it the multi - peaked structure . the transition from delocalized states to gap solitons was studied in detail ( by means of numerical methods ) in the first finite bandgap , for both cases of the repulsive and attractive nonlinearities . the above results , presented in terms of the dimensionless equations , can be easily translated into physical units . for instance , by considering an attractive bose - einstein condensate made of @xmath1li atoms , with scattering length @xmath212 nm , and choosing the transverse confining frequency as @xmath213 hz , we have a typical value of the modulation period , @xmath214 @xmath41 m , for @xmath71 ( recall it was a typical value for which the results were reported above ) . in this case the critical number of atoms at the collapse threshold is @xmath215 . the results may be quite useful to design new experiments in toroidal traps , where an azimuthal periodic potential can be induced , as explained above , by the spatially - modulated transverse confinement . the work of b.a.m . was partially supported by the israel science foundation through excellence - center grant no . 8006/03 , and by german - israel foundation through grant no . 149/2006 . l.s . acknowledges gnfm - indam for partial support . thank prof . alberto parola for numerous discussions and suggestions . g. l. alfimov , v. v. konotop , and m. salerno , europhys . lett . * 58 * , 7 ( 2002 ) ; b. b. baizakov , v. v. konotop , and m. salerno , j. phys . b * 35 * , 51015 ( 2002 ) ; p. j. y. louis , e. a. ostrovskaya , c. m. savage , and y. s. kivshar , phys . rev . a * 67 * , 013602 ( 2003 ) . equations ( [ var1 ] ) and ( [ var2 ] ) are solved by choosing @xmath136 as an independent parameter . then , defining @xmath216 and @xmath217 , one finds , after some algebraic manipulations , @xmath218 , and @xmath219 .

we derive an effective nonpolynomial schrdinger equation ( npse ) for self - repulsive or attractive bec in the nearly-1d cigar - shaped trap , with the transverse confining frequency periodically modulated along the axial direction . besides the usual linear cigar - shaped trap , where the periodic modulation emulates the action of an optical lattice ( ol ) , the model may be also relevant to toroidal traps , where an ordinary ol can not be created . for either sign of the nonlinearity , extended and localized states are found , in the numerical form ( using both the effective npse and the full 3d gross - pitaevskii equation ) and by means of the variational approximation ( va ) . the latter is applied to construct ground - state solitons and predict the collapse threshold in the case of self - attraction . it is shown that numerical solutions provided by the one - dimensional npse are always very close to full 3d solutions , and the va yields quite reasonable results too . the transition from delocalized states to gap solitons , in the first finite bandgap of the linear spectrum , is examined in detail , for the repulsive and attractive nonlinearities alike .

SECTION 1. SHORT TITLE. This Act may be cited as the ``Accountability and Flexibility Associated With Spending on Transportation Act of 2005''. SEC. 2. TRANSPORTATION FUNDING FLEXIBILITY. (a) Highway Bridge Program.--Section 144(g)(1) of title 23, United States Code, is amended by adding at the end the following: ``(D) Funding Flexibility.--If a State is provided funds under subparagraph (A) for a project described in subparagraph (A), the State may use all or any portion of such funds to carry out such project or any other project eligible for assistance under this section that the State designates.''. (b) Projects of National and Regional Significance.--Section 1301 of the Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (Public Law 109-59) is amended by adding at the end the following: ``(n) Funding Flexibility.--If a State is provided funds under this section for a project described in the table contained in subsection (m), the State may use all or any portion of such funds to carry out such project or any other project eligible for assistance under this section that the State designates.''. (c) National Corridor Infrastructure Improvement Program.--Section 1302 such Act is amended by adding at the end the following: ``(f) Funding Flexibility.--If a State is provided funds under this section for a project described in the table contained in subsection (e), the State may use all or any portion of such funds to carry out such project or any other project eligible for assistance under this section that the State designates.''. (d) High Priority Projects Program.--Section 117 of title 23, United States Code, is amended by adding at the end the following: ``(i) Funding Flexibility.--If a State is provided funds under this section for a project described in the table contained in section 1702 of the Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (Public Law 109-59), the State may use all or any portion of such funds to carry out such project or any other project eligible for assistance under the surface transportation program in section 133 that the State designates.''. (e) Transportation Improvements.--Section 1934 of such Act is amended by adding at the end the following: ``(d) Funding Flexibility.--If a State is provided funds under this section for a project described in the table contained in subsection (c), the State may use all or any portion of such funds to carry out such project or any other project eligible for assistance under the surface transportation program in section 133 of title 23, United States Code, that the State designates.''. (f) Projects for Bus and Bus-Related Facilities and Clean Funds Grant Program.--Section 3044 of such Act is amended by adding at the end the following: ``(d) Funding Flexibility.--If a recipient is provided funds under this section or section 5308 of title 49, United States Code, or both, for a project described in the table contained in subsection (a), the recipient may use all or any portion of such funds to carry out such project or any other project eligible for assistance under this section or section 5308 of such title, other than a project to fund any operations of buses or bus-related facilities.''. SEC. 3. SENSE OF CONGRESS. It is the sense of Congress that State departments of transportation should take project descriptions in section 144(g)(1)(A) of title 23, United States Code, and in the tables contained in sections 1301, 1302, 1702, 1934, and 3044 of the Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (Public Law 109-59) into consideration if such projects involve improving transportation safety. SEC. 4. ACROSS-THE-BOARD RESCISSIONS. (a) Fiscal Year 2006.-- (1) In general.--On September 30, 2006, there is rescinded $4,718,047,269 of the unobligated balances of funds apportioned before such date to the States for the Interstate maintenance, national highway system, bridge, congestion mitigation and air quality improvement, surface transportation (other than the STP set-aside programs), metropolitan planning, minimum guarantee, Appalachian development highway system, recreational trails, safe routes to school, freight intermodal connectors, coordinated border infrastructure, high risk rural road, high priority projects, and transportation improvements programs and each of the STP set-aside programs. (2) Allocation among states.--The Secretary shall determine each State's share of the amount to be rescinded by paragraph (1) by multiplying $4,718,047,269 by the ratio of the aggregate amount apportioned to such State for fiscal year 2006 for all the programs referred to in paragraph (1) to the aggregate amount apportioned to all States for such fiscal year for those programs. (3) Calculations.--To determine the allocation of the amount to be rescinded for a State under paragraph (2) among the programs referred to in paragraph (1), the Secretary of Transportation shall make the following calculations: (A) The Secretary shall multiply such amount to be rescinded by the ratio that the aggregate amount of unobligated funds available to the State on September 30, 2006, for each such program bears to the aggregate amount of unobligated funds available to the State on September 30, 2006, for all such programs. (B) The Secretary shall multiply such amount to be rescinded by the ratio that the aggregate of the amount apportioned to the State for each such program for fiscal year 2006 bears to the aggregate amount apportioned to the State for all such programs for fiscal year 2006. (4) Allocation among programs.-- (A) In general.--The Secretary, in consultation with the State, shall rescind for the State from each program referred to in paragraph (1) the amount determined for the program under paragraph (3)(A). (B) Special rule.-- (i) Restoration of funds for covered programs.--If the rescission calculated under paragraph (3)(A) for a covered program exceeds the amount calculated for the covered program under paragraph (3)(B), the State shall immediately restore to the apportionment account for the covered program from the unobligated balances of programs referred to in paragraph (1) (other than covered programs) the amount of funds required so that the net rescission from the covered program does not exceed the amount calculated for the covered program under paragraph (3)(B). (ii) Treatment of restored funds.--Any funds restored under clause (i) shall be deemed to be the funds that were rescinded for the purposes of obligation. (C) Covered program defined.--In subparagraph (B), the term ``covered program'' means a program authorized under sections 130 and 152 of title 23, United States Code, paragraph (2) or (3) of section 133(d) of that title, section 144 of that title, section 149 of that title, or section 1404 of the Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (Public Law 109-59). (5) Limitation on recalculation of equity bonus program.-- Notwithstanding any other provision of law, the amounts determined, and the amounts allocated, under section 105 of title 23, United States Code, for fiscal year 2006 shall not be recalculated to take into account a rescission made pursuant to this subsection. (6) STP set-aside program defined.--In this subsection, the term ``STP set-aside program'' means the amount set aside under section 133(d) of title 23, United States Code, for each of transportation enhancement activities and the division between urbanized areas of over 200,000 population and other areas. (b) Fiscal Year 2007, 2008, and 2009.-- (1) In general.--Subject to paragraph (2), there is rescinded 10 percent of each amount authorized to be appropriated for each of fiscal years 2007, 2008, and 2009 by the Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (Public Law 109-59), including any amendment made by such Act, and including any amount authorized to be appropriated for the equity bonus program under section 105 of title 23, United States Code, but excluding any amount authorized to be appropriated for the highway safety improvement program. (2) Timing.--A rescission made by paragraph (1) of an amount authorized to be appropriated for a fiscal year shall take affect on October 1 of such fiscal year before any apportionment or allocation of such amount and before such amount is subject to any set aside or subtraction. (3) Limitation on recalculation of equity bonus program.-- Notwithstanding any other provision of law, the amounts determined, and the amounts allocated, under section 105 of title 23, United States Code, for a fiscal year shall not be recalculated to take into account a rescission made by this subsection. (c) September 30, 2009.--Section 10212 of the Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (Public Law 109-59) is amended in subsection (a) by inserting after ``high risk rural road,'' the following: ``high priority projects, transportation improvements,''. (d) Reports.--Not later than the 60th day following the date of each rescission made by subsection (a) or (b), the Secretary of Transportation, in consultation with the Director of the Office of Management and Budget shall submit to the appropriate committees of Congress a report containing the amount rescinded for each program referred to in subsection (a) and the amount rescinded for each program or activity for which there is a rescission made by subsection (b).

Accountability and Flexibility Associated With Spending on Transportation Act of 2005 - Amends the Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (SAFETEA-LU) to allow a state to use its specified transportation improvement program (TIP) project allocation for any other eligible transportation project the state may designate. Expresses the sense of Congress that state departments of transportation should take project descriptions in certain set-aside bridge program projects and specified TIP projects under SAFETEA-LU into consideration if such projects involve improving transportation safety. Rescinds for FY2006 a specified amount of state unobligated balances of funds for the Interstate maintenance, national highway system, bridge, congestion mitigation and air quality improvement, surface transportation (other than the STP set-aside programs), metropolitan planning, minimum guarantee, Appalachian development highway system, recreational trails, safe routes to school, freight intermodal connectors, coordinated border infrastructure, high risk rural road, high priority projects, and TIPs and each of the STP set-aside programs. Rescinds 10% of amounts appropriated for FY2007-FY2009 by SAFETEA-LU (including the equity bonus program), but excluding amounts appropriated for the highway safety improvement program.

intermetallic compounds of rni@xmath7-type have been attracting considerable interest initiated by their remarkable physicochemical properties and potential applications as materials with high hydrogen storage capacity @xcite . their physical properties , which are characterized by a large variety of magnetic structures and electronic peculiarities , have been actively investigated , both theoretically and experimentally . substitution of one rare - earth metal r with another one modifies significantly these characteristics because of crystal field effects and changes of exchange interaction value between the conduction and 4f - localized electrons . on the the other hand substitution of ni for some other transition metal also leads to interesting physical phenomena . for example , series of isostructural rni@xmath0cu@xmath1 alloys was found experimentally to have non monotonic concentration dependence of the magnetic susceptibility , curie temperature t@xmath8 , electronic specific heat and resistivity @xcite . a number of studies indicate a direct correlation between this anomalous behavior of the parameters and band structure evolution with copper content increase @xcite . to explain these experimental data one needs more detailed investigation of electronic structure of the rni@xmath0cu@xmath1 series for different @xmath3 . there are several experimental and theoretical works on the rnicu compounds . x - ray photoemission study of lani@xmath0cu@xmath1 solid solution shows presence of cu-3d band , which is located almost 2 ev below the 3d band of ni and is weakly hybridized with the latter one @xcite . the calculation of ref . predicts the existence of a wide ( @xmath9 1,5 ev ) peak in the electron density of states of the yni@xmath0cu@xmath1 alloys at energies 2.5 - 4 ev below fermi level e@xmath10 , which is related to the 3d electrons of cu . the evolution of frequency dependencies of the optical conductivity of the tbni@xmath0cu@xmath1 compounds upon substitution of ni for cu atoms investigated in ref . . there it was observed that a new structure arises in the optical spectra ( a broad absorption maximum peaking at 4 ev ) while the cu content increases . detailed investigation of crystal structure and thermodynamic properties from both experimental and band structure calculation sides is done in ref . ( except for the optical properties ) . within this study we continue investigation of the electronic structure of tbni@xmath0cu@xmath1 isostructural alloy series with @xmath2 0 , 1 , 2 by carrying out self - consistent _ ab initio _ lsda+u calculations . disorder effects are taken into account in a combinatorial way with respect to possible number of cu positions for given doping . corresponding averaged over the cu positions spin resolved densities of states are calculated . following it interband contribution to the theoretical optical conductivity is determined . drude ( intraband ) contribution is taken as a lorentzian with experimentally determined parameters . comparison of our theoretical results with recent optical experiment is presented . the tbni@xmath7 compound crystallizes into a hexagonal structure of the cacu@xmath7 type with a space group p6/mmm and lattice parameters for x=0 @xmath11=@xmath12=4.8988 and @xmath13=3.96 ( see fig . [ fig1 ] ) , x=1 @xmath11=@xmath12=4.9126 and @xmath13=3.9901 and x=3 @xmath11=@xmath12=4.9351 and @xmath13=4.0113 .@xcite the nickel has two inequivalent crystallographic positions ni1(2c ) ( 1/3,2/3,0 ) and ni2(3 g ) ( 1/2,0,1/2 ) , tb has a position 1(a ) ( 0,0,0 ) . in fig . [ fig1 ] ni1 ions are represented by violet circles and located in the same `` layer '' as tb ions ( green circles , fig . [ fig1 ] ) . the ni2 ions ( red circles , fig . [ fig1 ] ) also form a `` layer '' . a calculations of the electronic structure of tbni@xmath0cu@xmath1 ( @xmath2 0 , 1 , 2 ) were performed within the linear muffin - tin orbitals ( lmto ) method @xcite . the program package tb - lmto - asa ( tight - binding lmto together with atomic spheres approximation ) v. 47 was employed @xcite . the subdivision of the first brillouen zone in the reciprocal space is ( 10 10 10 ) with 132 irreducible @xmath14-points . the atomic sphere radius for tb was obtained to be about 3.47 a.u . , for nickel and copper ions about 2.63 a.u . the orbital basis consists of 6s , 5d and 4f muffin - tin orbitals for tb , and 4s , 4p and 3d for cu and ni . lsda+u calculations on top of that were done as proposed in ref . with coulomb interaction parameters for tb(4f ) states @xmath15 5.4 ev and @xmath16 0.7 ev.@xcite also recently we showed that coulomb interaction for fe ions in intermetallides is almost completely accounted within lsda by itself.@xcite to introduce cu into the tbni@xmath7 system one or two ni ions were substituted with cu . to mimic disordered alloy we perform calculations for different possible positions of copper ions for chosen doping level @xmath3 . assuming that each possible cu position has the same weight we then average obtained partial densities of ni and cu-3d states with following ratios for corresponding ni wickhoff positions : for @xmath5 i.e. one copper ion 2(2c):3(3 g ) and @xmath17 , two cu ions , 1(2c):3(3g):6(2c+3 g ) . in our lsda+u calculations collinear ferromagnetic order of the local magnetic moments on all lattice sites was chosen . moreover the terbium and nickel sublattices are taken to be ferromagnetic with respect to each other . in this compound main magnetic moment is localized on terbium ions while nickel ions have a small magnetization because of almost completely occupied ni-3d shell in accordance with ref . . for parent tbni@xmath7 system local magnetic moments in units of bohr magneton are following : on tb(5.8 ) , ni1(0.27 ) and ni2(0.28 ) . total magnetic moment of tbni@xmath7 is 7.21 bohr magneton . with ni for cu substitution in tbni@xmath7 depending on cu position total magnetic moment goes down about 10 - 15% . these results agree well with experimental data of ref . . local magnetic moments on nickel ions become two to three times smaller . local magnetic moment on terbium insignificantly grows , while copper stays practically non magnetic . the fig . [ fig2 ] shows the total ( upper panel ) and partial ni(3d ) ( middle panel ) and cu(3d ) ( lower panel ) doses for up ( @xmath18 ) and down ( @xmath19 ) projections of local spin moments for the ferromagnetic tbni@xmath0cu@xmath1 ( x=0,1,2 ) compounds . structure of these dos for different x is rather similar to each other and agrees with ref . for stoichiometric tbni@xmath7 . it is seen that the main spectral weight is located below the fermi level . the 3d states of ni1 and ni2 form the wide bands extending from 4.0 to 0.5 ev . the 3d states of cu1 and cu2 bands for the compounds with x=1,2 are located in the energy range -4@xmath9 - 6 ev below e@xmath10 . their width is considerably smaller with respect to ni-3d states . the 4f - states of tb ion for majority spin are located below -6 ev and for minority at about 1.5 ev . calculated lsda+u band structures presented in the previous section are used to interpret experimental optical data @xcite for the systems under consideration . in order to calculate theoretical interband optical conductivity @xmath20 we applied a rather simplified technique @xcite using approximation , that the direct and indirect ( involving phonons ) interband transitions are equally probable . namely we computed @xmath20 like the integral function based on the convolution of the density of states located both below and above the @xmath21 . the electronic transitions of the d@xmath22f type are not observed in the calculation due to their low probability . this technique was already successively applied by us to intermetallic r@xmath23fe@xmath24 compounds @xcite . from total lsda+u dos presented on upper panel of fig . [ fig2 ] one can observe decrease of total dos on the fermi level @xmath6 with cu doping . it happens because for x=0 @xmath6 consists mostly of ni-3d states . with doping number of ni ions goes down while newly introduced cu ions do not contribute to the @xmath6 ( see lower panel of fig . [ fig2 ] ) . figure [ fig3 ] displays corresponding theoretical optical conductivity @xmath25 ( solid lines ) together with experimental frequency dependencies of the optical conductivity @xmath26 ( dots ) for tbni@xmath0cu@xmath1 ( @xmath2 0 , 1 , 2 from top to bottom ) . in the energy region below @xmath9 0.5 ev the behavior of @xmath26 for all compositions sharp drude peak is determined experimentally . corresponding height and width of drude peak ( 127@xmath27 s@xmath28 and 0.280 ev for @xmath29 , 156@xmath27 s@xmath28 and 0.278 ev for @xmath5 , 130@xmath27 s@xmath28 and 0.288 ev for @xmath17 ) were extracted from these curves and then used to draw theoretical one ( see inset of fig . [ fig3 ] ) . as follows from above mentioned static conductivity ( drude peak height ) it goes down with doping . it agrees with lowering of @xmath6 in our lsda+u calculations since conductivity is proportional to @xmath6 . in its turn plasma frequency is also proportional to @xmath6 and thus should decrease with cu doping . on the other hand substitution of ni for cu adds one electron to the system and increases number of carriers . plasma frequency squared is proportional to the number of carriers ( in the simplest drude - like picture ) and then should grow with cu doping . these two competing tendencies lead to the non monotonic doping behavior of plasma frequency recently observed experimentally in ref . . at energies above 0.7 ev the shape of @xmath26 dispersion indicates the dominant role of interband absorption . the wide absorption region is characterized by structures , which intensities and localizations depend on the compound composition . the optical conductivity of the tbni@xmath7 binary alloy ( upper curve ) exhibit two peaks at photon energies 1.15 and 1.9 ev respectively . in the tbni@xmath30cu compound the @xmath26 spectrum is almost the same ; we can only note that the minimum between these structures is less pronounced . with a further increase in the cu content ( @xmath17 ) a new fairly broad absorption band arises at energies 3 - 4.5 ev . corresponding theoretical optical conductivity curves @xmath20 shows evolution upon substitution of nickel with copper similar to experimental one . theoretical calculations reproduce qualitatively the basic features of the experimental spectra , namely , two - peak structure at 1 - 2.5 ev , associated with the ni 3d interband transitions . the depth about 1.5 ev is getting closed . high energy tail above 3 ev becomes smoother with doping increase and for @xmath17 one can see the formation of the `` cu - states '' peak at about 5 ev . somewhat higher energy position of leading interband absorption edge ( about 1 ev ) might come from uncertainties in computation of @xmath31 value . in this work we perform _ ab initio _ lsda+u computations of electronic structure of intermetallic isostructural alloys tbni@xmath0cu@xmath1 ( @xmath2 0 , 1 , 2 ) . disorder effects of ni for cu substitution were accounted in a combinatorial way . corresponding averaged over all possible cu positions for given doping level x dos are further used to compute theoretical optical conductivity . here we is theoretically explain how experimental optical conductivity line shape changes with doping . analyzing lsda+u calculated dos one can find that responsible for the structures of optical conductivities at 1 - 2 ev electronic states are predominantly ni-3d states , while at @xmath94 - 5 ev there are cu-3d states . amount of latter ones increases upon doping giving rise to the structure at 4 - 5 ev in optical conductivity . one should note also good semiquantitative agreement between theoretical and experimental data . finally in this work we give explanation of the experimentally observed maximum of plasma frequency for x=1@xcite as competition of lowering of @xmath6 and simultaneous growing of number of carriers with ni for cu substitution . this work is partly supported by rfbr grant 08 - 02 - 00021 and was performed within the framework of programs of fundamental research of the russian academy of sciences ( ras ) `` quantum physics of condensed matter '' ( 09-@xmath32 - 2 - 1009 ) and of the physics division of ras `` strongly correlated electrons in solid states '' ( 09-t-2 - 1011 ) . in thanks grant of president of russia mk-614.2009.2 , interdisciplinary ub - sb ras project , and russian science support foundation . a. n. pirogov , j .- park , a. s. ermolenko , a. v. korolev , a. g. kuchin , s. lee , y. n. choi , j. park , m. ranot , j. yi , e. g. gerasimov , yu . a. dorofeev , a. p. vokhmyanin , a. a. podlesnyak , i. p. swainson , phys . rev . b * 79 * , 174412 ( 2009 ) .

in this paper we present theoretical investigation of optical conductivity for intermetallic tbni@xmath0cu@xmath1 series . in the frame of lsda+u calculations electronic structure for @xmath2 0 , 1 , 2 and on top of that optical conductivities were calculated . disorder effects of ni for cu substitution on a level of lsda+u densities of states ( dos ) were taken into account via averaging over all possible cu ion positions for given doping level @xmath3 . gradual suppression and loosing of structure of optical conductivity at 2 ev together with simultaneous intensity growth at 4 ev correspond to increase of cu and decrease of ni content . as reported before [ knyazev @xmath4 , optics and spectroscopy * 104 * , 360 ( 2008 ) ] plasma frequency has non monotonic doping behavior with maximum at @xmath5 . this behavior is explained as competition between lowering of total density of states on the fermi level @xmath6 and growing of number of carriers . our theoretical results agree well with variety of recent experiments .

the interest in the ( 110 ) surfaces of mo and w has been fostered in recent years by the discovery of deep and extremely sharp indentations in the energy loss spectra of he atom scattering at h / mo(110 ) and h / w(110 ) @xcite . as depicted in fig . [ fanom ] those anomalies are seen at an incommensurate wavevector , @xmath2 , along the @xmath3 $ ] direction ( @xmath4 ) and additionally at the commensurate wavevector @xmath5 at the boundary of the surface brillouin zone ( sbz ) . at those points two simultaneous anomalies develop out of the ordinary rayleigh mode . one , @xmath6 , is extremely deep , and is only seen by helium atom scattering ( has ) @xcite . the other , @xmath7 , is instead modest , and is observed by both has and high resolution electron energy loss spectroscopy ( hreels ) @xcite . since the @xmath3 $ ] components of both critical wavevectors @xmath8 and @xmath9 are approximately the same it was suggested that the anomaly runs parallel to @xmath10 through the sbz as illustrated in fig . [ flocus ] . various models have been brought forward in order to account for the unusual vibrational properties of h - covered mo(110 ) and w(110 ) : for instance , a pronounced but less sharp softening of surface phonons is also seen on the ( 001 ) surfaces of w @xcite and mo @xcite . there , the effect is caused by marked nesting properties of the fermi surface @xcite . however , angular resolved photoemission ( arp ) experiments of h / w(110 ) and h / mo(110 ) gave no evidence for nesting vectors comparable to the has determined critical wave vectors @xcite ( see fig . [ ffermiexp ] ) . thus , for the phonon anomalies of those two systems there seems to be no connection between the electronic structure and the vibrational properties . moreover , even if such a relation existed it would be unclear whether the phenomena has to be interpreted as a kohn anomaly or as the phason and amplitudon modes associated with the occurance of a charge - density wave . in fact , the experimental finding of two modes at @xmath11 as well as some theoretical arguments rule out the phason - amplitudon idea @xcite . furthermore , any model which links the phonon anomalies to the motion of the hydrogen atoms @xcite has to be ruled out because the has spectra remain practically unchanged when deuterium is adsorbed instead of hydrogen @xcite . still unexplained , but probably not directly correlated to the anomalies , is the peculiar behavior of hydrogen vibrations observed in hreels experiments by balden _ et al . _ @xcite . at a h - coverage of one mono - layer the adsorbate modes parallel to the surface form a continuum interpreted a liquid - like phase of the adsorbate . an additional puzzle to the already confusing picture is added by the observation of a symmetry loss in the low - energy electron diffraction ( leed ) pattern of w(110 ) upon h - adsorption . the phenomena was believed being caused by a h - induced displacement of the top layer w atoms along the @xmath12 $ ] direction @xcite ( see figs.[fstruc]b and c ) . for h / mo(110 ) similar studies do not provide any evidence for a top - layer - shift reconstruction @xcite . the goal of our work is to give a comprehensive explanation for the observed anomalous behavior and clarify the confusing picture drawn by the different experimental findings . we show that the anomalous behavior observed in the he and electron loss experiments is indeed governed by h - induced nesting features in the fermi surface . the remainder of the paper is organized as follows . first , section [ smeth ] gives a brief introduction into the _ ab initio _ method used . the results of our work are presented in section [ scalc ] : in subsection [ satom ] we study the atomic geometry of the clean and h - covered mo(110 ) and w(110 ) surfaces . in particular , we check whether the hydrogen adsorption induces a top - layer - shift reconstruction . following in subsection [ selec ] , we focus on the electronic structure of those surface systems . in this context , we are particularily interested in how the fermi surface changes upon h - adsorption : is there evidence for fermi - surface nesting ? if yes , how does it connect to the arp measurements of the fermi surfaces and the critical wavevectors detected by has and hreels ? along the same line within the model of a kohn anomaly , subsection [ sphon ] digs into the coupling between electronic surface states and surface phonons . there , we discuss the mechanism which causes the small anomaly @xmath6 . in subsection [ ssusc ] we examine the he scattering mechanism , study the spectrum of electron - hole excitations , and explain the physical nature of the huge anomalous branch @xmath7 . finally , the major aspects of our work are summarized in section [ ssumm ] . the appendix presents several detailed test calculations giving an insight into the properties and the accuracy of our method . all our calculations employ the density - functional theory ( dft ) . they are performed within the framework of the local - density approximation ( lda ) for the exchange - correlation energy functional @xcite . for the self - consistent solution of the kohn - sham ( ks ) equations we employ a full - potential linearized augmented plane - wave ( fp - lapw ) code @xcite which we enhanced by the direct calculation of atomic forces @xcite . combined with damped newton dynamics @xcite this enables an efficient determination of fully relaxed atomic geometries . also , it allows the fast evaluation of phonon frequencies within a frozen - phonon approach . there exists a variety of different lapw programs @xcite . we therefore briefly specify the main features of our code . this is also in order to clarify the meaning of the lapw parameters which determine the numerical accuracy of the calculations . in the augmented plane - wave method space is divided into the interstitial region ( ir ) and non - overlapping muffin - tin ( mt ) spheres centered at the atomic sites @xcite . this division accounts for the atomic - like character of the wavefunctions , the potential , and the electron density close to the nuclei and that the behavior of these quantities is smoother in between the atoms . the basis functions @xmath13 which we employ in our code for the expansion of the electron wavefunctions of the ks equation @xmath14 are defined as @xmath15y_{lm}(\hat{r}_i ) } , & r_i \le s_i \quad . \end{array}\right.\ ] ] here , @xmath16 denotes the sum of a reciprocal lattice vector @xmath17 and a vector @xmath18 within the first brillouin zone . the wavefunction cutoff @xmath19 limits the number of those @xmath20 vectors and thus the size of the basis set . the other symbols in eq.([ewfbas ] ) have the following meaning : @xmath21 is the unit cell volume , @xmath22 specifies the mt radius , and @xmath23 represents a vector within the mt sphere of the @xmath24-th atom . note that @xmath25 is a complex spherical harmonic with @xmath26 . the radial functions @xmath27 and @xmath28 are solutions of the equations @xmath29 y_{lm}(\hat{r})\end{aligned}\ ] ] which are regular at the origin . here , the ks operator @xmath30 contains only the spherical average of the effective potential within the respective mt . the expansion energies @xmath31 are chosen somewhere within the respective energy bands with @xmath32-character , whereas the coefficients @xmath33 and @xmath34 are fixed by requiring that value and slope of the basis functions are continuous at the surface of the @xmath24-th mt sphere . obviously , this can only be fulfilled for @xmath35 , but as @xmath36 is typically high ( e.g. @xmath37 ) this does not represent a problem . the representation of the potentials and densities resembles the one employed for the wavefunctions , i.e. , @xmath38 thus , no shape approximation is introduced . the quality of this full - potential description is controlled by the cutoff parameter @xmath39 for the reciprocal lattice vectors @xmath17 and the maximum angular momentum @xmath40 of the @xmath41-representation inside the mts . the substrate surfaces are modeled by five- , seven- , and nine - layer slabs repeated periodically and separated by a vacuum region whose thickness is equivalent to four substrate layers . the mt radii for the w and mo atoms are chosen to be @xmath42 . note that the experimental interatomic distances of bulk mo and w are 2.73and 2.74 , respectively . for hydrogen the mt radius is set to @xmath43 . in the case of the w surfaces the valence and semi - core electrons are treated scalar - relativistically while the core electrons are handled fully relativistically . for mo all calculations are done non - relativistically . in both metals we introduce a second energy window for the treatment of the semi - core electrons ( 4@xmath44 and 4@xmath45 for mo , 5@xmath44 and 5@xmath45 for w ) . the in - plane lattice constants ( compare fig . [ fstruc ] ) @xmath46 and @xmath47 are calculated to be without including zero - point vibrations . they are in good agreement with the respective measured bulk lattice parameters at room temperature and other theoretical results ( see appendix [ abulk ] ) . for the potential the @xmath41 representation within each mt sphere is taken up to @xmath48 while the kinetic - energy cutoff for the interstitial region is set to @xmath49ry . generally , we choose the plane - wave cutoff for the wavefunctions to be @xmath50ry ; only for the frozen - phonon calculations we use a slightly smaller cutoff of @xmath51ry which is indeed sufficient . the @xmath41 representation of the wavefunctions within the mts is taken up to @xmath52 . also , we employ fermi smearing with a broadening of @xmath53mev in order to stabilize the self - consistency and the @xmath54-summation . all energies given below are however extrapolations to zero temperature @xmath55 @xcite . we performed systematic tests comparing the lda and the generalized gradient approximation @xcite exchange - correlation functionals . for the quantities reported in this paper ( total energy differences of different adsorption sites , bond lengths , etc . ) both treatments give practically the same results . all @xmath18 sets used were determined by using the special @xmath18 point scheme of monkhorst and pack @xcite . also , we checked the @xmath54-point convergence : in the case of atomic and electronic structure calculations a two - dimensional uniform mesh of 64 @xmath54-points within the @xmath56 sbz gives stable results . for the evaluation of frozen - phonon energies a set of 56@xmath54-points is employed within the sbz of the enlarged @xmath57 and @xmath58 surface cells ( see subsection [ sappphon ] ) . in table [ tparam ] we summarize the main features of our lapw parameter setting . for more details the reader is referred to the discussion in the appendix . for some systems involving hydrogen the results of a total energy calculation are not reliable if the lda is used . in those cases the bonding especially between hydrogen atoms is only described accurately if gradient corrections are considered @xcite . in table [ tfrozxc ] we compare results obtained with the generalized gradient approximation ( gga ) @xcite and those found within the lda . the latter is identical with the 56 @xmath59-point calculation in table [ tfrozenerdiff ] . there , the xc potential of cepereley and alder @xcite parametrized by perdew and zunger @xcite is used . the small energy and force differences of 5mev and 8mev / , respectively , clearly shows that our adsorbate systems are rather insensible to the xc formalism chosen .

helium atom scattering ( has ) studies of the h - covered mo(110 ) and w(110 ) surfaces reveal a twofold anomaly in the respective dispersion curves . in order to explain this unusual behavior we performed density functional theory calculations of the atomic and electronic structure , the vibrational properties , and the spectrum of electron - hole excitations of those surfaces . our work provides evidence for hydrogen adsorption induced fermi surface nesting . the respective nesting vectors are in excellent agreement with the has data and recent angle resolved photoemission experiments of the h - covered alloy system mo@xmath0re@xmath1(110 ) . also , we investigated the electron - phonon coupling and discovered that the rayleigh phonon frequency is lowered for those critical wave vectors . moreover , the smaller indentation in the has spectra can be clearly identified as a kohn anomaly . based on our results for the susceptibility and the recently improved understanding of the he scattering mechanism we argue that the larger anomalous dip is due to a direct interaction of the he atoms with electron - hole excitations at the fermi level . = 10000

ABC Obama campaign senior adviser David Axelrod insisted he is confident that newly launched investigations will show that recent leaks on classified national security information did not come from the White House. "I think the authors of all of this work have said that the White House was not the source of this information," Axelrod told me this morning on "This Week." "I can't say that there weren't leaks. There were obvious leaks, but they weren't from the White House." Axelrod said Obama takes all "life or death decisions" on national security seriously, and that the White House would not leak information that may jeopardize classified operations. "He understands that when he commits people to missions that their lives are at stake, and the safety of Americans are at stake," Axelrod said. "And the last thing that he would countenance or anybody around him would countenance are leaks that would jeopardize the security of Americans on these secret missions, and the success of those missions." Both Republicans and Democrats have accused the White House of releasing details of various secret operations, including the effort to sabotage Iran's nuclear program, for political purposes in order to bolster President Obama's national security credentials before the election. President Obama disputed that charge Friday at a White House press conference, saying, "The notion that my White House would purposefully release classified national security information is offensive. It's wrong." Attorney General Eric Holder said Friday that two federal prosecutors would lead investigations into the leaks to news outlets, including The New York Times. When I asked if he was confident the investigations would not show White House involvement, Axelrod said "Yes," citing the administration's history of cracking down on leaks. "We have come under attack because we have been tougher on leaks than any administration in recent history And we have been criticized for that," Axelrod said. "We want to make sure that the people we assign to these very difficult tasks are safe, or as safe as they can be." ||||| Two stories published by the New York Times, which exposed the extent of U.S. involvement in cyber attacks against Iran and the White House’s secret 'Kill List,' have sparked scrutiny over the last week amid allegations that administration officials had leaked classified information for political gain.The debate continued Sunday as Sen. John McCain (R-Ariz.) reiterated calls for a special prosecutor to take charge of leak investigations and as a reporter who wrote one of the stories said he doubted that any politically motivated leaks were involved.David Sanger, chief Washington correspondent for the New York Times, appeared on CNN ’s “Reliable Sources” to defend his reporting on U.S. involvement in deploying the Stuxnet computer virus against Iran.Sanger said that during 18 months of reporting for his book “Confront and Conceal: Obama’s Secret Wars and Surprising Use of American Power,” he obtained information from the ground up. He said he had serious doubts as to whether there were any political motivations behind the leaks.“Did I talk to a lot of people in the administration? Of course,” he said, as would be expected when writing a book about national security.Sanger contended that how Obama conducts himself in the theater of international military action is key for the public to know, and is a necessary story for the media to report on, regardless of the secrecy associated with national security issues.“Can we debate them out in the open? Of course,” he said.McCain dismissed Atty. Gen. Eric H. Holder ’s appointment of two federal prosecutors to oversee the investigation.“Mr. Holder’s credibility with Congress, there is none. We continue to have this problem with him withholding information on Fast and Furious, which resulted in the killing of a border patrol agent in Arizona. He is close to being held in contempt,” McCain said on CNN’s “State of the Union.” Darrell Issa (R-Calif.), chairman of the House committee investigating the Fast and Furious operation – an effort to track gun purchases by Mexican drug cartels that lost track of many of the weapons – has proposed holding Holder in contempt. Democrats have dismissed the effort as political grandstanding.“This information had to have come from the administration. It couldn’t have come from anywhere else,” McCain said, referring to details in Sanger’s book. “The president may not have done it himself, but he’s certainly responsible as commander in chief.”

– The public's right to know about the president and his policies outweigh secrecy and security issues, says David Sanger, the New York Times reporter behind one of two much-criticized articles on the White House's approach to national security, reports the LA Times. Sen. John McCain has repeatedly attacked the White House for leaking sensitive information to boost its profile, specifically via Sanger's story about the president's role in stepping up cyberattacks on Iran's nuclear program. But Sanger, who is coming out with a book about national security under President Obama, titled Confront and Conceal: Obama’s Secret Wars and Surprising Use of American Power, says those issues are fair game and important for the press—but, of course, he doesn't reveal his sources. “Did I talk to a lot of people in the administration? Of course,” said Sanger, without naming names. “Can we debate" the issues "out in the open? Of course.” President Obama's senior campaign adviser, meanwhile, continued to defend the White House from leak accusations, telling ABC News that the administration would not compromise national security. “I can’t say that there weren’t leaks," said David Axelrod. "There were obvious leaks, but they weren’t from the White House."