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Browse our Culture Dictionary Alphabetically
Some terms acquire new meaning faster than a typical dictionary can capture the change. The American Heritage New Dictionary of Cultural Literacy includes contemporary word usage as well as essential and classic terms from the Bible, mythology, philosophy, literature, world history, geography, anthropology, psychology, and sociology. The New Dictionary of Cultural Literacy is a wonderful alternative for learning the meaning of important words and ideas.
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SPENCER CREEK. Spencer Creek rises at Spencer Springs in the southeastern Chinati Mountains in southwest Presidio County (at 29°48' N, 104°27' W) and runs southwest for fourteen miles to its mouth on the Rio Grande, one mile below Adobes (at 29°42' N, 104°31' W). It crosses desert mountain terrain of sedimentary deposits and inactive alluvial fans of gravel and sand that support sparse grasses, cacti, and desert shrubs. The creek was named for John Spencer, an early Presidio County settler, who operated a horse ranch on the creek near Indio in the 1850s.
The following, adapted from the Chicago Manual of Style, 15th edition, is the preferred citation for this article."SPENCER CREEK," Handbook of Texas Online (_URL_ accessed May 25, 2013. Published by the Texas State Historical Association.

source: HuggingFaceFW/fineweb-edu


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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: IS 240VAC two-phase - NO
Original poster: BunnyKiller
Tesla list wrote:
>Original poster: dhmccauley-at-spacecatlighting-dot-com
>240VAC is correctly denoted as SPLIT single phase. It is NOT two phase.
>It is simply a centertapped, 240VAC single phase line from a single phase
>Two phase denotes a phase angle difference of 180 degrees. The sum of all
>phases in any system must always equal 360 degrees. The standard home
>electrical system in the US is two phase, 180 degree difference( two times
>180 equals 360). Each phase is 125 volts RMS to neutral, and 250 volts RMS
>from phase to phase.
when testing the house wiring with my O-scope.. the 120V shows a single
sine wave... when testing the 240 system it shows 2 sine waves ( had to
use both leads)
so how does a single phase get "split" via a center tap transformer to
produce the opposed phases???


Amazon Machine Images: HVM or PV?
Learn the differences between HVM and PV for Amazon Machine Images.
Amazon Machine Images (AMIs) have a virtualization type of "HVM" or "PV." What is the difference and which should I choose?
Steve MillidgeSteve Millidge
Under the covers, AWS runs the Xen hypervisor on the bare metal of its servers. Xen has the capability to virtualize in two ways: Hardware Virtual Machine (HVM) or paravirtualization (PV).
Paravirtualization is a lightweight form of virtualization which differs from HVM in that it doesn't require any virtualization extensions from the host CPU. If your host server doesn't have Intel VT or AMD-V hardware extensions, then you'll need your guest to be paravirtualized.
PV does, however require that a guest OS has a "Xen-PV-enabled kernel" as well as PV drivers, meaning that the guests know that they are running in a hypervisor.
HVM guests are fully virtualized, so the underlying hardware has to be emulated for the guests to use, incurring performance cost, unlike PV, where the guest OS is modified to be able to run without needing that emulation.
If none of this is making sense so far, let me simplify; HVM requires the host machine to have a certain feature present in its hardware, whereas PV requires the guest OS to have a certain feature present in its software.
In practical terms, PV means that performance is much closer to what you would expect of the underlying hardware compared to HVM because of the extra overheads in HVM. As the Xen wiki says: "Fully virtualized guests are usually slower than paravirtualized guests, because of the required emulation."
The answer is simple, then: Choose PV instances because of the better performance. Right? Well, mostly. Since PV requires software changes, it is not possible to run a paravirtualized Windows guest.
The actual answer is nearly simple, then: If you need Windows, you'll need HVM. If you are using GNU Linux or Unix, you can choose either, but will (in most cases) get better performance with PV. The only caveat to make is that HVM isn't supported for t1.micro GNU/Linux instances.
For further reading, there's a good overview of these different types of guests in the Xen wiki.
This was first published in May 2014
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A page to help you get started on the ebikes. Please read before you take one out.
Peddle assist ebikes. To go faster:
- peddle harder
- put in harder gear
- increase motor speed
- use accelerator
You can just use motor and accelerator but then you might as well be on a scooter.
Try peddle assist where you peddle, change gears to make easier. Start off in Motor level 3 and increase as needed. Need a extra bit of zap, use the accelerator.
To conserver battery (if you want longer rides)
- try not to use accelerator or very gently accelerate.
- peddle harder.
- put motor at lower level.
- turn off on longer down hills.
- turn off battery when stopped for more than 5 minutes.
How to use
1. Turn on battery.
2. Press button untill screen comes on. Its now ready to go.
3. Press the + and – sign to increase decrease the motor power for peddle assist. 0 is off and 9 is max. Start with 2 or 3.
4. Use the accelirator when you dont want to peddle or need a little extra zap!
> To charge the battery plug the charger into the battery next to the battery on off switch.
> There are sensors on the brakes and rear tire. If a! mark is shown check the sensors are close to the brakes and the rear tire sensor magnet and sensor are inline (red light will come on sensor when wheel spun).

source: openbmb/Ultra-FineWeb


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not a power of 6.
n_start => $n option can select a different initial N. The tree structure is unchanged, just the numbering shifted. As noted above the default Nstart=0 corresponds to powers in a generating function.
n_start=>1 makes the numbering correspond to digits of N written in base-k. For example k=10 corresponds to N written in decimal,
N=1 to 9 1/2...... 2/1 N=10 to 99 1/4 4/7...... 7/4 4/1 N=100 to 999 1/6 6/11...... 11/6 6/1
n_start=>1 makes the tree
N written in base-k digits depth = numdigits(N)-1 NdepthStart = k^depth = 100..000 base-k, high 1 in high digit position of N N-NdepthStart = position across whole row of all top trees
And the high digit of N selects which top-level tree the given N is under, so
N written in base-k digits top tree = high digit of N (1 to k, selecting the k-1 many top nodes) Nrem = digits of N after the highest = position across row within the high-digit tree depth = numdigits(Nrem) # top node depth=0 = numdigits(N)-1
Chan shows that each denominator Y becomes the numerator X in the next point. The last Y of a row becomes the first X of the next row. This is a generalization of Stern's diatomic sequence and of the Calkin-Wilf tree of rationals. (See Math::NumSeq::SternDiatomic and "Calkin-Wilf Tree" in Math::PlanePath::RationalsTree.)
The case k=2 is precisely the Calkin-Wilf tree. There's just one top node 1/1, being the even k "middle" form h/h with h=k/2=1 as described above. Then there's two children of each node (the "middle" pair of the even k case),
k=2, Calkin-Wilf tree X/Y / \ (1X+0Y)/(1X+1Y) (1X+1Y)/(0X+1Y) = X/(X+Y) = (X+Y)/Y
See "FUNCTIONS" in Math::PlanePath for behaviour common to all path classes.
$path = Math::PlanePath::ChanTree->new ()
$path = Math::PlanePath::ChanTree->new (k => $k, n_start => $n)
Create and return a new path object. The defaults are k=3 and n_start=0.
$n = $path->n_start()
Return the first N in the path. This is 0 by default, otherwise the
$n = $path->xy_to_n ($x,$y)
Return the point number for coordinates
$x,$y. If there's nothing at
Each point has k children, so the path is a complete k-ary tree.
_USER_ = $path->tree_n_children($n)
Return the children of
$n, or an empty list if
$n < n_start(), ie. before the start of the path.
$num = $path->tree_n_num_children($n)
Return k, since every node has k children. Or return
$n < n_start(), ie. before the start of the path.
$n_parent = $path->tree_n_parent($n)
Return the parent node of
$nhas no parent either because it's a top node or before
$n_root = $path->tree_n_root ($n)
Return the N which is root node of
$depth = $path->tree_n_to_depth($n)
Return the depth of node
undefif there's no point
$n. The tree tops are depth=0, then their children depth=1, etc.
$n = $path->tree_depth_to_n($depth)
$n = $path->tree_depth_to_n_end($depth)
Return the first or last N at tree level
$depthin the path. The top of the tree is depth=0.
$num = $path->tree_num_roots ()
Return the number of root nodes in
$path, which is k-1. For example the default k=3 return 2 as there are two root nodes.
_USER_ = $path->tree_root_n_list ()
Return a list of the N values which are the root nodes of
$path. This is
n_start()+k-2inclusive, being the first k-1 many points. For example in the default k=2 and Nstart=0 the return is two values
$num = $path->tree_num_children_minimum()
$num = $path->tree_num_children_maximum()
Return k since every node has k many children, making that both the minimum and maximum.
$bool = $path->tree_any_leaf()
Return false, since there are no leaf nodes in the tree.
For the default k=3 the children are
3N+2, 3N+3, 3N+4 n_start=0
n_start=>1 then instead
3N, 3N+1, 3N+2 n_start=1
n_start=1 the children are found by appending an extra ternary digit, or base-k digit for arbitrary k.
k*N, k*N+1,..., k*N+(k-1) n_start=1
In general for k and Nstart the children are
kN - (k-1)*(Nstart-1) + 0... kN - (k-1)*(Nstart-1) + k-1
The parent node reverses the children calculation above. The simplest case is
n_start=1 where it's a division to remove the lowest base-k digit
parent = floor(N/k) when n_start=1
n_start adjust before and after to an
parent = floor((N-(Nstart-1)) / k) + Nstart-1
For example in the default k=0 Nstart=1 the parent of N=3 is floor((3-(1-1))/3)=1.
The post-adjustment can be worked into the formula with (k-1)*(Nstart-1) similar to the children above,
parent = floor((N + (k-1)*(Nstart-1)) / k)
But the first style is more convenient to compare to see that N is past the top nodes and therefore has a parent.
N-(Nstart-1) >= k to check N is past top-nodes
As described under "N Start" above, if Nstart=1 then the tree root is simply the most significant base-k digit of N. For other Nstart an adjustment is made to N=1 style and back again.
adjust = Nstart-1 Nroot(N) = high_base_k_digit(N-adjust) + adjust
The structure of the tree means
depth = floor(logk(N+1)) for n_start=0
For example if k=3 then all of N=8 through N=25 inclusive have depth=floor(log3(N+1))=2. With an
n_start it becomes
depth = floor(logk(N-(Nstart-1)))
n_start=1 is the simplest case, being the length of N written in base-k digits.
depth = floor(logk(N)) for n_start=1
This tree is in Sloane's Online Encyclopedia of Integer Sequences as
k=3, n_start=0 (the defaults) A191379 X coordinate, and Y=X(N+n)
As noted above k=2 is the Calkin-Wilf tree. See "OEIS" in Math::PlanePath::RationalsTree for "CW" related sequences.
Copyright 2012, 2013, 2014 Kevin Ryde
This file is part of Math-PlanePath.
Math-PlanePath is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version.
Math-PlanePath is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with Math-PlanePath. If not, see .


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Animal-related tourism is big business. Many people are willing to pay money to take selfies with sloths, ride elephants, pet tigers, and walk with lions. Unfortunately, some of these ventures are unethical, requiring animals to live in abusive conditions or contributing to biodiversity loss.
On December 4 of last year, Patricia Maunder released an article on Traveller.com that lists seven animal-related tourist experiences that no one should ever do. These experiences have a high probability of being unethical, and paying for them drives the mistreatment of the animals involved. These seven experiences are:
- Elephant experiences, like riding and bathing elephants.
- Interacting with apex predators, such as cub petting and walking with lions.
- Holding wild animals, often for the purpose of taking selfies.
- Wild animal shows, AKA circuses that feature wild animals.
- Swimming with captive dolphins.
- Buying souvenirs that are made from wild animal parts.
- Eating bushmeat, which is meat from wild animals.
In her article, Maunder goes into considerable detail about the seven experiences listed above. She explains in which countries and continents they are most problematic, why they are often bad for animals, and how to distinguish ethical wildlife-related experiences from unethical ones.
All-in-all, Maunder's story is a great read: it is full of useful information, it is well-written, and it will help travelers to make good decisions about where to spend their money. Please, click the link below to read the original article. While you are at it, why not share Maunder's piece with any travelers you might know?


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Dairy products may help ward off diabetes. A study published in the Journal of the American Medical Association reveals overweight participants who consumed four or more servings of dairy a day had a lower risk of developing insulin resistance syndrome, or I-R-S. The study observed trends in dairy consumption and the development of I-R-S, a precursor to type two diabetes, also known as adult-onset diabetes.
The reduced incidence of I-R-S in the ten year study was the same regardless of age, sex, race, dietary and lifestyle factors. Researchers won't make dietary recommendations, but they claim the study shows a definite trend of reduced risk among overweight dairy consumers.


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At the Forefront of International Science and Technology Policy Education
Scientific and technological advances provide the basis of international competitiveness and account for the bulk of national growth and the improvement of the quality of life around the world. The ability to create, adapt, and adopt new technologies defines modern societies. In today's global environment, the need for innovation is essential for solving societal problems and staying ahead of competition. Developments in information technology, space exploration, genetic modification and advances in material science are governed and shaped by institutions that set science and technology policy.
Innovation for a Secure Future
Ray O. Johnson, Senior Vice President and Chief Technology Officer, Lockheed Martin Corporation, discusses the relationships between universities and industry and the importance of both for a secure future.


text:
6 Definitions of Pas
The definition of pas, the meaning of the word Pas:
Is pas a scrabble word? Yes!
- n. - (ballet) a step in dancing (especially in classical ballet)
- n. - An informal term for a father; probably derived from baby talk
- n. - A short-lived radioactive metallic element formed from uranium and disintegrating into actinium and then into lead
- n. - A unit of pressure equal to one newton per square meter
- n. - A Mid-Atlantic state; one of the original 13 colonies
- n. - An electronic amplification system used as a communication system in public areas
Pas is worth 5 points in Scrabble, and 6 points in Words with Friends
There are 3 letters in pas: A P S
3 Anagrams of Pas
Words that can be created with an extra letter added to pas:
5 words found using the letters in "Pas"
3 Letter Words
2 Letter Words
Sign up for our Free Scrabble Words newsletter. We won't send you spam or share your email address with anyone. We Promise.


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whether the short first leaf with the rounded tip is included. If in doubt with these newer herbicides, check with your ag. chemical technical representative to verify which leaf staging method is appropriate for the herbicide you intend to use.
Staging Older Plants. As corn plants develop, the lower few leaves typically die or are torn away from the stem by the expansion of the stalk or by developing roots. Consequently, growth stage identification can be difficult on older plants when you aren't sure which leaves to begin counting first. But, not to worry, growth staging can still be accomplished!
First, dig or pull a plant without breaking the stalk. With a knife, carefully split the stalk down the middle, completely through the root ball. Look for the lowermost obvious internode (the whitish area between the "woody" horizontal stalk nodes) above the triangular "woody" base of the stalk. This first internode's length is typically only 1/2 to 3/4 inch.
Determine which leaf corresponds with the node immediately above the first noticeable internode by carefully identifying which leaf sheath attaches to the node. This leaf is usually Leaf #5. Once Leaf #5 is identified, then stage the plant by continuing to count the remainder of the leaves with visible leaf collars above Leaf #5. For example, assume you've identified Leaf #5 and there are six more leaves above that one with visible leaf collars, then the plant is at leaf stage V11 (11 leaves with visible leaf collars).
Typical deterioration of lower leaves in older corn plants
Split stalk illustrating the first distinguishable node above the pithy triangle
Loux, Mark, Anthony F. Dobbels, Jeff Stachler, Bill Johnson, Glenn Nice, & Tom Bauman. 2010. 2010 Weed Control Guide for Ohio and Indiana (WS-16). Table 7: Rainfast Intervals, Spray Additives, and Maximum Crop Size for Postemergence Corn Herbicides. Purdue Univ. & Ohio State Univ. Coop. Ext. Services. [On-Line]. Available at . [URL accessed May 2010].
Nielsen, R.L. (Bob). 2008. Tips for Staging Corn with Severe Leaf Damage. Corny News Network, Purdue Univ. [On-Line]. Available at . [URL accessed May 2010].
Nielsen, R.L. (Bob). 2008. Use Thermal Time to Predict Leaf Stage Development in Corn. Corny News Network, Purdue Univ. [On-Line]. Available at . [URL accessed May 2010].
Nielsen, R.L. (Bob). 2010. Heat Unit Concepts Related to Corn Development. Corny News Network, Purdue Univ. [On-Line]. Available at . [URL accessed May 2010].
Purdue University. 2010. Corn & Soybean Field Guide (ID-179). To order, call Purdue Extension toll-free at _PHONE_ and ask for the Media Distribution Center.
Ritchie, S.W., J.J. Hanway, and G.O. Benson. 1993. How a Corn Plant Develops (SP-48). Iowa State Univ. [On-Line]. Available at . [URL accessed May 2010].
Heat Unit Concepts Related to Corn Development – (Bob Nielsen)
Growth and development of corn are strongly dependent on temperature. Corn develops faster when temperatures are warmer and more slowly when temperatures are cooler. For example, a string of warmer than normal days in late spring will encourage faster leaf development than normal. Another example is that a cooler than normal grain filling period will delay the calendar date of grain maturity.
The phrases "string of warmer than normal days" and "cooler than normal grain filling period" can be converted mathematically into measures of thermal time by calculating the daily accumulations of heat using temperature data. Commonly used terms for thermal time are Growing Degree Days (GDDs), Growing Degree Units (GDUs), or heat units (HUs).
Different methods exist for calculating heat units depending on a) the crop or biological organism of interest and b) the whim or personal preference of the researcher. The calculation method most commonly used throughout the U.S. for determining heat unit accumulation relative to corn phenology is the formula first suggested by the National Oceanic and Atmospheric Administration in 1969 and labeled as the "'Modified Growing Degree Day" formula in 1971.
This method calculates daily accumulation of GDDs as the average daily temperature (°F) minus 50. The "modification" refers to the limits imposed on the daily maximum and minimum temperatures allowed in the calculation. Daily maximums greater than 86 degrees F are set equal to 86 in the calculation of the daily average temperature. Similarly, daily minimums less than 50 degrees F are set equal to 50 in the calculation.
If the daily maximum temperature was 80°F and the minimum was 55°F, the GDD accumulation for the day would be ((80 + 55) / 2) – 50 or 17.5 GDDs.
Example 2: (Illustrating the limit on daily maximums):
If the daily maximum temperature was 90°F and the minimum was 72°F, the GDD accumulation for the day would be ((86 + 72) / 2) – 50 or 29 GDDs.
Example 3: (Illustrating the limit on daily minimums):
If the daily maximum temperature was 68°F and the minimum was 41°F, the GDD accumulation for the day would be ((68 + 50) / 2) – 50 or 9 GDDs.
In late April to early May, normal daily GDD accumulations for central Indiana are about 10 GDDs. By late July, the normal daily accumulation rises to about 23 GDDs. For a typical corn growing season in central Indiana, say from late April to late September, the total seasonal accumulation of GDDs is about 2800 GDDs.
Historical normal GDD accumulations on a weekly basis for Indiana's nine Crop Reporting Districts are listed in the accompanying table and are also available in Purdue's Corn & Soybean Field Guide, Extension publication ID-179. These historical GDD values can be used to estimate weekly GDD accumulations if you do not have access to current temperature data.
Obviously, the ability to calculate daily heat unit accumulations is dependent on your having access to daily maximum and minimum temperatures. If you do not own your own max / min recording thermometer, you can guesstimate the daily highs and lows by manually recording the temperatures shortly after sunrise (approximate daily low) and late in the afternoon (approximate daily high).
Another option is to try your luck with the online Indiana State Climate Office data archive . At this Web site, you can search for temperature data from the automated Purdue weather stations located at a number of outlying Purdue Ag. Centers, cooperative weather stations maintained by the National Weather Service, and airport weather stations also maintained by the National Weather Service. Also, the weekly Pest&Crop newsletter lists accumulated GDDs for selected sites across the state based on various start dates.
Corn & Soybean Field Guide (ID-179). 2010. Purdue Univ. Extension. To order, call Purdue Extension toll-free at _PHONE_.
Nielsen, R.L. (Bob). 2008. Use Thermal Time to Predict Leaf Stage Development in Corn. Corny News Network, Purdue Univ. [On-Line]. Available at . [URL accessed May 2010].
Nielsen, R.L. (Bob). 2010. Determining Corn Leaf Stages. Corny News Network, Purdue Univ. [On-Line]. Available at . [URL accessed May 2010].
Purdue Pest & Crop Newsletter. 2010. Purdue Univ. Pest Mgmt. Program. [On-Line]. Available at . [URL accessed May 2010].
Every year, for the first five weeks or so after corn planting is finished, the guys down at the Chat 'n Chew Cafe complain royally about the looks of the crop. It does not matter whether it was an early planting season or a late planting season. Gripes about uneven stands, poor color, and slow growth waft over the tables as everyone airs their concerns about the looks of their neighbors' fields.
Then suddenly one day, the tone of the conversation in between the coffee and sweet rolls perks up. Almost overnight, the crop has taken off like a rocket. The color of the leaves turns a dark, almost-blue green and they develop a distinct shine. From that point on, any connoisseur of corn feels better about life in general.
Why does this transition seem to happen over and over again every year?
During the first five weeks or so after planting, the corn plant is going about the business of creating all of the leaves it will ever have. A few of these leaves are visible, but most are wrapped tightly


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First Nations children have the right grow up safely at home, get a good education, be healthy, and be proud of their cultures
It's an obvious truth but it's far from being a reality.
As the Auditor General of Canada and many others have noted, the Federal government provides less funding per child for many services for First Nations children on reserves than the Provinces provide for children in their jurisdictions. This is despite often higher costs of delivering such services in small and remote communities, and the greater need experienced by many First Nations communities.
The result of the denial of basic rights that most people in Canada take for granted.
The annual Have a Heart Day campaign is about involving ordinary people across Canada in demanding an end to this fundamentally unjust situation. The campaign is led by the First Nations Child and Family Caring, a dynamic non-profit organization led by Dr. Cindy Blackstock which advocates for the rights of First Nations children. The Caring Society says, "Have a Heart Day is about caring Canadians working together to ensure First Nations children have proper services that make them feel proud of who they are."
Amnesty International has worked alongside the Caring Society for years to raise awareness of the ongoing discrimination in the funding and quality of basic government services available to First Nations children. Also in February we will once again standing alongside Dr. Blackstock and the Caring Society as the long awaiting Canadian Human Rights Tribunal hearing into the Society's discrimination complaint against the Federal government is finally heard.
The Caring Society has made joining the Have a Heart Day campaign easy. You can take part by sending a Valentine's Day card or letter to the Prime Minister and your Member of Parliament, hosting a Valentine's Day party to raise awareness in your school or community, or by spreading the word through social media like YouTube, Twitter, and Facebook.
Last year, people across Canada celebrated Have a Heart day in all sorts of energizing and creative ways. Southeast Child and Family Services in Manitoba collected over 5000 Valentine's Day cards to send to Parliament. Students at Carleton University held a bake sale, and community members in Saskatchewan celebrated with an educational puppet show.
Visit the Have a Heart Day website at www.fncaringsociety/have-a-heart for more information, to send an e-Valentine, or to order Have a Heart Valentine's cards, posters, bookmarks, and buttons!
To find the contact details for you Member of Parliament, visit the Parliament of Canada website.
However you take part in Have a Heart Day, please let us know. It's really important to build a picture of all the activity taking part across the country. Please drop us a line - and send pictures, if you can - to _EMAIL_
There is also an ongoing related action on our own website at:


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Document / Publication
This paper addresses the difficult decisions policy-makers are often tasked with in the face of an uncertain future outlook. It hopes to provide an introduction to many of the key concepts of climate change adaptation or 'serious games'. More importantly it aims to highlight the synergies between the three disciplines and lay the foundations for further elaboration and insight. All this is while maintaining the overarching goal of empowering actors in enhancing their capabilities and level of agency to deal with climate change and uncertainty. It asks if the infrastructural investments will still be relevant in 25 years, what new markets are likely to emerge in the medium term, and how a gradual increase in average temperatures over the coming decades will affect livelihood security.
The paper describes what processes are needed to promote Flexible and Forward-looking Decision Making (FFDM). More specifically, the paper proposes a coupled game and reflection based approach, looking to capitalise on the ability of serious games to encourage experiential learning, as well as ensuring that enough time is provided to reflect on how key components of the game relate to the 'real-world'. It also allows participants to identify their own routes forward for improving decision-making processes. It lays the groundwork for the second phase of research under the Africa Climate Change Resilience Alliance (ACCRA), who will be researching the principles outlined within, as well as trialling three separate coupled game-and reflection events across its core countries, namely Ethiopia, Uganda and Mozambique.


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This recipe allows you to filter a report for follow-up tickets. It can be used to include or exclude those tickets.
Skill level: Intermediate
Time: 15-30 minutes
This recipe requires two custom metrics and a numeric range filter.
Step 1: Create Ticket Creation Events metric
Use the recipe from this article: Insights recipe: Ticket creation events. Make it a global metric, so you can use it in any report.
Step 2: Create Follow-Up Tickets metric
Open the metric editor and create this metric:
- SELECT IFNULL((SELECT(SELECT Ticket Creation Events WHERE Ticket Update Via=Closed Ticket) BY Ticket Id ALL OTHER WITHOUT PF), 0)
Please note: You can't copy and paste in the metric editor. The color-coded items need to be selected from the Elements pick-list on the right:
- Ticket Creation Events is the metric from Step 1. It will be under Metrics
- Ticket Update Via and Ticket Id are under Attributes
- Closed Ticket is under Attribute Values > Ticket Update Via
- When you select "Attribute Values," it will show you the Attributes list. That's normal. Select "Ticket Update Via" to see all available values, then add "Closed Ticket."
Make this a global metric as well, so you can add it to any report.
The "BY Ticket Id ALL OTHER WITHOUT PF" portion means this metric will only consider Ticket IDs; it will ignore all other report and dashboard filters. (The PF stands for Parent Filter.) The underlying Ticket Creation Events metric is only looking at one specific ticket update. On its own, it may not accurately filter a report on other ticket updates. This "ALL OTHER" portion means the metric always applies to the ticket as a whole. It makes the metric more effective as a filter, but less useful to display under WHAT.
Step 3: Add a Numeric Range Filter
You do not need to display these metrics in the report under WHAT. You just need to create and save them, so they'll be available for a filter.
Create a report based on ticket data, then add a Numeric Range Filter:
- For the Attribute, choose Ticket Id
- For the Metric, choose the Follow-Up Tickets metric from Step 2
- For the Range, you have two options:
- "Is equal to 0" means you will only see tickets that are NOT follow-up tickets
- "Is equal to 1" means you will only see tickets that ARE follow-up tickets
Finding other types of tickets
This recipe is designed to find follow-up tickets specifically. You can easily modify the recipe to find other types of tickets instead.
For example, to find tickets from different channels, pick different values for Ticket Update Via. To find tickets created by agents, add a condition for the Updater Role.
You can get into a lot of detail with the conditions in this metric. As long as the overall metric follows this template, it should behave the same way in filters.


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Knowing the hill forest on the west slopes of Gunung Palung from my thesis research at the Cabang Panti Research Station many years ago, I have been looking forward to seeking differences in tree composition in this valley. Most of the valley's forest occurs on ridges and slopes of granite-derived sandy soils (see this paper by Chuck Cannon & Mark Leighton). However, around our camp there is also some lovely, flat alluvial forest, at an elevation of 230 meters. An area of very hard rock (a basalt dike?) underlies the valley a half kilometer downstream from our campsite, creating a high waterfall called Riam Parit. This block seems to have 'dammed' the erosional deposits in the valley above, creating a surprisingly large area of flat, fertile alluvium.
Low-elevation alluvial forests near the big rivers of Borneo are the most diverse on the island and contain the biggest trees, and are also the first to be converted to agriculture. It will be interesting to see if this slightly higher elevation alluvial forest, isolated from the true alluvial forests, contains any of the tree species typical of these forests. My first impression, as we set up our first 50 square meter inventory plot on Friday, is that most of the species on this alluvium are typical of granite hill forest, but are those requiring higher nutrient sites. However, some species (e.g., Dipterocarpus tempehes) are seldom found in hill forest and must be small, relatively isolated populations. As soon as we have marked out the six survey plots (three in alluvium and three on the drier hills), we'll begin assessing the species composition to provide a better idea of what is growing here. Stay tuned.


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Run QBASIC on Android
QBASIC is a simple programming language. It was made and launched in 1964 by John G. Kemenny and Thomas E. Kurtz. QBASIC is now owned by Microsoft. QBASIC stands for Quick Beginners' All-purpose Symbolic Instruction Code. It has simple commands like CLS, Input, Print, Let, GOTO, IF…THEN etc. QBASIC has Characterized User Interface (CUI). It is similar to MS-DOS. Almost all the Microsoft OS can run QBASIC.
Android is a Linux-based Mobile Operating System. It is found in many Samsung phones like Samsung Galaxy Series. Nearly all the PC Tabs use Android OS. Android users enjoy many advanced features that are not found in PCs. What if they could create small programs in their phones? Yes, they can by using QBASIC.
But, there is no QBASIC application on Google Play. How will they create programs? It's simple with aDOSBox. It is an Android DOS Emulator.
Let's start programming!
- The first thing you will have to do is download aDOSBox (Android DOSbox) to your Android Device. Here is the URL: _URL_
- After it is installed, you can open it and explore the app. The font maybe too small, but it is readable. Some phones have small screen, so there might be a problem understanding the texts.
- Now, the final thing you need is the QBASIC application. This is a Windows application, not Android. You might have the QB.EXE or qbasic.exe file on your computer.
- Copy it to your SD Card. Make a folder called "QBASIC" and move the QBASIC application to it.
- Open aDOSbox.
- Type the command 'CLS' and press enter.
You'll be seeing this:
- Then, type the following:
mount d /sdcard/qbasic
- Note that there is a space between d and /
- After that, /sdcard/qbasic will be mounted as local directory.
- Type d:
- You will be taken to D: directory i.e. SD Card. C: is Phone Memory and D: is the SD Card.
- Type the name of the QBASIC application present inside the QBASIC folder. If it's QB.exe, then type QB.exe and press enter
- After a second or two, the QBASIC screen appears!
You will have to learn how to move mouse pointer yourself. It's not that difficult. You first need to enable Mouse Emulation feature. When you slide your finger to right, the mouse pointer moves right. Take it to the desired place and press anywhere on the screen to click on the menu or area. My phone screen is small, so the font size is small and the graphics are not clear. However, QBASIC works the same way on your phone as in the computer. You can save programs, run them, change background color, create subs etc. If you want to exit QBASIC, then click on File and then Exit. The experience is amazing in a Tablet.
Check out some screenshots:
Check out some QBASIC programs here: _URL_
Share your experiences on comment. Thank you. Have fun!


text:
, by offering multiple metal layers, is the best candidate to design three dimensional (3D) µCoils with specific geometry suitable for high resolution NMR spectroscopy. In this section, we demonstrate and discuss the design and simulation results of two different µCoil structures, namely serial stacked coils (SSC) and differential stacked coils (DSC) shown in Figure 5a,b.
SSC is a simple structure consisting of multiple planar coils in different layers (with i layers). These planar coils (with j turns) are connected through inter-metal vias in order to achieve large inductance values as seen in Figure 5c. However, the equivalent resistance will be increased as expressed in Equation (3).
The DSC is a symmetrical differential structure consisting of multiple planar µCoils (i layers, and j turns in each layer) that are connected to each other with two vias [31,32]. The equivalent resistance of a DSC structure as expressed in Equation (4)
As described in, in our design, each layer consists of multiple parallel coils in order to increase the magnetic field B1. Therefore, a number of vias are used to connect the µCoils between two layers as seen in Figure 5d.
The equivalent circuit model of both DSC ad SSC structures is a tank circuit and therefore the quality factor of their equivalent circuits can be expressed by
where Leq and Ceq are the equivalent inductance and capacitance and Req is the equivalent resistance that can be obtained from Equation (3) or Equation (4) for EEC and DSC structures, respectively. Based on Equations (3)–(5), one can roughly conclude that quality factor of the DSC structure is higher than the SSC structure. This is because Req-SSC >> Req-DSC. Next, in Section 3.2.2, we calculate the quality factor using the finite-element electromagnetic simulator HFSS.
Two different topologies of the stacked inductors (DSC and SSC) are designed in a CMOS compatible manner using eight metal layers. In this design, from a circuit point of view, two parameters are important for designing µCoils. These parameters are the self-resonant frequency f0 and the quality factor, which determines the noise level of the µCoil. Additionally, in the design of µCoils, the silicon area is another very important factor that should be minimized. The ANSYS HFSS software is employed to search for an optimum geometry at f0 = 300 MHz. Based on these studies, the quality factors of both structures versus frequency are obtained as shown in Figure 5e.
The optimum inner and outer diameters of the hexagonally shaped DSC structure are 80 and 365 µm respectively. The same geometry was also used for the SSC structure. As the results of HFSS modeling and simulation show, the operating frequencies of SSC and DSC structures are 40 MHz and 300 MHz, respectively as seen in Figure 5e. As expected (see Section 3.2.1) due to the differential configuration of DSC, the quality factor of the differential inductor is around 2, a value seven times better than the SSC structure's quality factor.
Another advantage of the DSC structure is the homogeneity of the magnetic field B1 generated inside the µCoil. As seen in both structures (see Figure 5c,d), the metal vias introduce horizontal magnetic field components which affect the homogeneity of the magnetic field B1. In the DSC structure, the current flows through the vias between each two layers are in opposite directions. These opposite current directions almost cancel the horizontal magnetic field components. Therefore, one can argue that the symmetric structure of the DSC can almost cancel out the magnetic parasitic effects while the asymmetric structure of the SSC cannot. The magnetic field generated by these asymmetric and symmetric structures in three different directions (B1x, B1y and B1z) is demonstrated in Figure 6a–f.
As seen in these figures, the magnetic fields in the x and y directions are less than the magnetic field in the z direction in both DSC and SSC structures in the middle of the coils. The ratio of the B1xy over B1z is 3.02% (33.67/1114) at the center point of the SSC while this ratio is 0.93% (11.89/1274) at the center point of the DSC. Based on these values, the vertical magnetic field B1z in both structures are close to each other while the DSC has lower magnetic field in the xy-plane in comparison to the SSC structure. In addition, one can see the distribution of the B1z in the middle volume of the DSC and SSC structures, in Figure 6g,h, respectively. Based on these results, the mean values of the B1z for the DSC and SSC are 1290 A/m and 1115 A/m, respectively. Furthermore, the standard deviation of the DSC is around 59.5 A/m which is about half of the standard deviation of the SSC which is about 108 A/m. Based on all these results, we can say that the uniformity of the magnetic field in the DSC structure is much better than that of the asymmetric structure. This is the key advantage of the DSC structure for NMR spectroscopy. The computational results shown in Figure 6g,h prove this concept. In these figures the population vs. magnetic field strength are shown. The central cross sections each coil is devided into a large number of small square or so-called pixel. Total population of pixels with certain magnetic stregnth Hz is ploted in Figure 6g,h. Therefore, thess plots can show the uniformity of magnetic field in the center of the microcoil with a DSC structure is much better the one with a SSC structure.
It is noteworthy that the quality factor of μCoils implemented in CMOS is lower than the quality factor of μCoils reported in. This low quality factor quality is due to the thin underneath aluminum layers in CMOS technology. On the other hand, CMOS offers the advantage of developing multiple μCoils along with conditioning circuitries on a single chip. Herein, we improved the quality factor by connecting multiple layers using vias between them. The winding density and diameter of μCoils shown in Figure 6 are about 17 turns/360 micron.
As described in Section 2.1, the design of the low noise amplifier is key for the development of high resolution NMR spectroscopy. A low noise amplifier system consists of two parts: a preand a post-amplifier.
As already mentioned in Section 4.1, it is very crucial to replace the impedance matching with a passive voltage amplifier as reported in [6,32]. Figure 7a shows the circuit model of such a passive pre-voltage amplifier. This LC resonator consists of an on-chip DSC inductor in parallel with a tuning capacitor. A MIM capacitor in a CMOS process is used for this purpose. By assuming that LNA's input impedance is very high, the voltage gain of this pre-amplifier can be obtained from the following equation.
The optimum capacitance can also be obtained by taking differential of Equation (6) at C ()
Therefore, by choosing C appropriately, the voltage gain peaks as shown in Figure 7b, at a frequency of around 300 MHz. Indeed, this input LC structure (pre-amplifier) boosts the weak NMR signal with minimal noise corruption for the ensuing signal processing. This pre-amplification is followed by a post amplifier shown in Figure 7c.
The post-amplifier is a fully differential cascode push-pull LNA that is designed and implemented for NMR spectroscopy purposes. In this circuit, M1–M4 form the core of the LNA and constitute a differential cascade voltage amplifier circuit to suppress the common mode noise. In this sub-circuit, M1–M2 are NMOS and M3–M4 are PMOS transistors. The total voltage gain can be obtained from.
where gm1 and gm3 are the transconductances of the NMOS and PMOS input transistors and R3 = R4 are output resistive loads. M7–12 and R1 = R2 constitutes a bootstrap voltage reference's circuitry to regulate bias of amplifier. This circuitry is used to minimize the thermal effect on biasing of circuitry. On the other hand, M13–M14 as well as M11 mirrors the bias currents of M8.
For noise performance, we need to optimize the noise source of M1–M4. According to the circuit shown in in Figure 7c, the input referred noise due to M1 and M3 can be stated as follows.
where T, k and γ are temperature in Kelvin, Boltzmann constant and the drain thermal noise excess factor respectively. Based on this equation, the noise can be reduced by increasing the DC currents or gm1 and gm3. However the extra DC current increases the power consumption and consequently the temperature that results in higher thermal noise level. In other words, by designing low-power-consumption circuitry, we can prevent the self-heating of the chip.
The layout and simulation results of the proposed integrated circuit are demonstrated and discussed in this section. The HFSS and Cadence design suites were used to model and simulate the µCoil and IC circuit, respectively. The layout of this circuit can be seen in Figure 8.
As noted above, the LNA is designed to achieve an optimum input referred noise. Therefore, we designed the LNA with a large


text: This is a great activity that goes with the new book in the Sir Cumference series. The book is titled Sir Cumference and the Viking's Map. It is a story that correlates with coordinate graphing. The activity I made to go along with the book is a "map" graph and a set of ten sentences that have students mark an X at each of the stops (coordinate points). This is a great way to tie reading into your math lesson or math into a reading lesson.


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Researchers at King's College London have identified a gene linked to age-related degeneration of the intervertebral discs, a common cause of lower back pain.
Back pain costs the United Kingdom an estimated £7billion ($11 billion in US dollars) a year due to sick leave and treatment costs. Lumbar disc degeneration (LDD) is inherited in 65%-80% of people with the condition, suggesting that genes play a key role. Until now, the genetic cause of lower back pain associated with LDD was unknown, says King's.
For this study, scientists compared MRI images of the spine in 4,600 individuals with genome-wide association data, which mapped the genes of all the volunteers. They identified that the gene PARK2 was implicated in people with degenerate discs and could affect the speed at which they deteriorate.
The researchers say the results show that the gene may be switched off in people with LDD. Although it is still unclear how this might happen, it is thought that environmental factors, such as lifestyle and diet, could trigger this switch by making changes known as epigenetic modifications to the gene.
was published online September 19 in Annals of Rheumatic Diseases.


text:
The IDA Louisiana Branch was chartered in 1987 as the Louisiana Dyslexia Society in order to increase public awareness of dyslexia, and become a branch of the Orton Dyslexia Society in 1991, followed by a name change in 1997 to incorporate the new name – The International Dyslexia Association. In 2001, the Mississippi Branch of the IDA dissolved and was then affiliated with the Louisiana Branch.
A variety of professionals, parents and adults with dyslexia comprise the all volunteer board, representing all of Louisiana and Mississippi. Many of the board's members are actively involved in the diagnosis and remediation of dyslexia and believe that all individuals have the right to achieve their potential, that individual learning abilities can be strengthened and that educational, social and cultural barriers to language acquisition and use must be removed. The board actively promotes effective teaching practices and related educational intervention strategies for individuals with dyslexia and is committed to the dissemination of research-based knowledge that supports multi-sensory direct, explicit, structured language that is sequential for instructing students with dyslexia.
The branch does not maintain an office. For information, sponsors, conferences, workshops, a speakers bureau and other public events please email us. Through the years the IDA louisiana Branch has developed a strong collaborative network with related organizations throughout Louisiana and Mississippi.
You can get involved by joining the International Dyslexia Association. The benefits of membership include:
- access to a network of learning disability professionals
- a subscription to the IDA Louisiana Branch newsletter
- discounts on publications
- discounts on conferences
- a subscription to Perspectives on Language and Literacy
- a subscription to Annals of Dyslexia
The International Dyslexia Association's annual conferences and seminars offer an excellent educational opportunity for parents, educators and professionals.
International Dyslexia Association, Louisiana Branch
149 Jefferson Oak Drive
Ruston, LA 71270
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text:
【本期主题】Rainy Day Liquidity
Insurance companies collectively hold nearly one-third of corporate bonds, making it critical to understand their roles in the corporate bond market: liquidity providers or consumers? In this study, we coin a new term "rainy day liquidity providers" for the potential role of insurance companies – with cash flow from core business activities, insurers may provide liquidity to the sell side in times of market stress. Our empirical findings present strong support to rainy day liquidity provision hypothesis. First, based on widely used bond liquidity measures, we find that, on average, insurer corporate bond purchases improve bond liquidity while it is not the case for insurer bond sales. Second, breaking the sample down into bonds of different rating groups, maturity groups, crisis and non-crisis periods, we show that liquidity provision by insurers is much stronger in stressful conditions. Finally, we present evidence that rainy day liquidity provision effect goes beyond bonds purchased by insurers – the liquidity of bonds with similar characteristics to the purchased (sold) bonds also increases during stressful periods.
【报告人】Tong Yu 教授， University of Cincinnati
Tong Yu is a Professor of Finance in the Lindner School of Business at the University of Cincinnati. His research and teaching have been focused on asset pricing, financial risk management, insurance, and behavior of institutional investors. He published academic journals such as the Journal of Financial Economics, Journal of Accounting Research, Journal of Financial Intermediation, Journal of Banking and Finance, and Journal of Risk and Insurance, and practitioner journals including the Financial Analyst Journal and Journal of Insurance Regulations. Dr. Yu received the Early Career Scholarly Achievement Award from the American Risk and Insurance Association in 2011. Before joining UC, he was a professor of finance at the University of Rhode Island.


text:
Culture - Day 2 grades K-3 learning activities
These activities will help youth build awareness and learn to identify city resources. They can be done alone, but work best with friends over a video chat such as Skype, Zoom, Facetime, etc.
Trivia question: In what year did Calgary become a city?
A) 2000 B) 1899 C) 1950 D) 1894
- Take a deep breath in and squeeze your fists as tight as you can.
- Hold it for 5 seconds.
- Blow all the air out through your mouth and shake your hands and arms as fast as you can.
- Pencil Crayons
- Give your child a piece of paper and pencil
- Have your child divide the sheet into four sections (they can fold the paper or draw lines).
- Help them write 4 of their favourite places in Calgary (one in each section).
- Have them draw each place.
- Share the drawings with family members and see if anyone else has the same favourite places.
Using household items, have your child build their very own skyscraper at home! See how tall they can make it and imagine what it would look like in downtown Calgary.
If they want to and have enough supplies, build more skyscrapers to make their own downtown.
- Pencil crayons
- Markers and/or crayons
For this activity, have your child draw a map of their dream city.
They can draw buildings, stores and houses like they see in Calgary. They can also make up amazing new attractions, like a chocolate fountain or a sledding race course.
Have them name their new city. How many people live there? What do people do for fun? Are there any special events or festivals?
Ask your child:
- What's your favourite thing about Calgary?
- What makes Calgary special?
- How can you make Calgary an even better place?
Mindfulness Activity: 1894. Calgary is 126 years old!


text:
Top Stories - Posted by Jessalyn Tenhouse-Missouri on Wednesday, April 18, 2012 12:33 - 2 Comments
No single 'God spot' in human brain
U. MISSOURI (US) — New research challenges the idea that the human brain has a "God spot," a distinct area responsible for spirituality.
Work by University of Missouri researchers indicates spirituality is a complex phenomenon, and multiple areas of the brain are responsible for the many aspects of spiritual experiences.
Based on a previously published study that indicated spiritual transcendence is associated with decreased right parietal lobe functioning, the team replicated their findings.
In addition, the researchers determined that other aspects of spiritual functioning are related to increased activity in the frontal lobe. The findings are reported in the International Journal of the Psychology of Religion.
Straight from the Source
"We have found a neuropsychological basis for spirituality, but it's not isolated to one specific area of the brain," says Brick Johnstone, professor of health psychology.
"Spirituality is a much more dynamic concept that uses many parts of the brain. Certain parts of the brain play more predominant roles, but they all work together to facilitate individuals' spiritual experiences."
In the most recent study, Johnstone studied 20 people with traumatic brain injuries affecting the right parietal lobe, the area of the brain situated a few inches above the right ear. He surveyed participants on characteristics of spirituality, such as how close they felt to a higher power and if they felt their lives were part of a divine plan.
He found that the participants with more significant injury to their right parietal lobe showed an increased feeling of closeness to a higher power.
"Neuropsychology researchers consistently have shown that impairment on the right side of the brain decreases one's focus on the self," Johnstone says. "Since our research shows that people with this impairment are more spiritual, this suggests spiritual experiences are associated with a decreased focus on the self.
"This is consistent with many religious texts that suggest people should concentrate on the well-being of others rather than on themselves."
Johnstone says the right side of the brain is associated with self-orientation, whereas the left side is associated with how individuals relate to others. Although Johnstone studied people with brain injury, previous studies of Buddhist meditators and Franciscan nuns with normal brain function have shown that people can learn to minimize the functioning of the right side of their brains to increase their spiritual connections during meditation and prayer.
In addition, Johnstone measured the frequency of participants' religious practices, such as how often they attended church or listened to religious programs. He measured activity in the frontal lobe and found a correlation between increased activity in this part of the brain and increased participation in religious practices.
"This finding indicates that spiritual experiences are likely associated with different parts of the brain," Johnstone says.
More news from the University of Missouri: _URL_


Harper Ben Lyrics
Harper Ben Bio
Harper was born in Claremont, in California's Inland Empire. His father, Leonard, was of African-American and Cherokee ancestry, and his mother, Ellen Chase-Verdries, is Jewish. His maternal great-grandmother immigrated from Lithuania. His parents divorced when he was five, and he grew up with his mother's family. Harper has two brothers, Joel and Peter.
Harper began playing guitar as a child. His maternal grandparents' music store The Folk Music Center and Museum laid a foundation of folk and blues for the artist, complemented by regular patrons Leonard Cohen, Taj Mahal and David Lindley and quotes of William Shakespeare and Robert Frost made often by his grandfather. During the '80s, in his teen years, Harper began to play the slide guitar, mimicking the style of Robert Johnson. Next, Harper refined his style, taking up the Weissenborn. Harper broke out of the Inland Empire after being offered an invitation by Taj Mahal to tour with the artist. The 20 year-old Harper and the blues legend then recorded Follow the Drinking Ghour(d) and toured Hawaii.
Source: _URL_


M.D. Coverley
M.D. Coverley is the pen name for Marjorie Coverley Luesebrink. She is an American writer, scholar, and teacher. Coverley is renowned for her hypermedia fiction, and is best known for her epic hypertext novels, Califia and Egypt: The Book of Going Forth by Day. Her works incorporate text, image, animation, sound, and structure to create spatial, visual story worlds. A pioneer born-digital writer, she is part of the first generation of electronic literature authors that arose in the _PHONE_ period. Her career includes novels and short stories, scholarship, curating, editing, teaching, and publishing. She is the founding board member and past president of the Electronic Literature Organization and the first winner of the Electronic Literature Organization Career Achievement Award, which was named in her honor. (Source: Wikipedia; approved by M. Luesebrink.)


text:
DNA Replication Rates lower Eukaryotes and Prokaryotes... why a difference...
dellaire at ATLAS.ODYSSEE.NET
Tue Jan 16 01:05:18 EST 1996
>for a biology paper,=20
>i need to solve the follwing question:
>WHY IS DNA REPLICATION IN PROKARYOTES NEARLY 100 TIMES FASTER THAN
>REPLICATION IN EUKARYOTES?
The numbers I have quote:
E.coli at 500 nt/s and Human Fibroblast at 50 nt/s
that would be 10X faster
>i have wondered if it is because of (a) life span of pro vs eu
>karyotes, (b) because of existence ofa nuclear membrane in eukaryotes,
>where one is not found in prokaryotes...
>if anyone can shed some light on this question, please reply by
>posting or send email to:
k.venkiteswaran at odyssey.on.ca
Here are a few possibilities I could come up with.
One, in E.coli you are not worrying about mutations that much.
In fact =
a high mutation rate is desirable if the bacterium is to adapt
changing environments. The result is you can replicate your DNA
without worrying about a mutation occurring. In higher
eukaryotes such =
as mammals this is a big problem... mutations can kill the
organism if well placed (i.e. cancer). For yeast I don't think
this is =
as strong a point as they are unicellular and much like in
--high mutation rates are adaptive.
The error rate in E.coli is consequently ~10-8 where as in
Fibroblasts it is ~10-10
Two in E.coli you have very little packing of DNA compared to
eukaryotes. To start DNA replication you need to gain access to
the DNA =
and expose the template for the polymerase. For instance you
have the =
HU protein of bacteria compared to H1, H2A, H2B, H3 and H4 as
well as =
the HMG proteins in mammals. The bacterial genome is much less
so by simple logic to replicate DNA it is much easier to gain
accesss to =
DNA in bacteria then in a mammal and hence it is faster in
Further as a point of interest
In E.Coli you only have one origin of replication where as in
cells it is estimated there are between 10 to the 4 --10 to the
possible origins. This may reflects both the difference in size
complexity of the two genomes as well as the speed at which DNA
replicated. Multiple initiations of replication could help
increase the =
time to replicate the genome if it is very large.
E.Coli has 3 X10 to the 6 bp and in the human genome there are
~3X 10 to =
the 9 or=20
1000X more DNA to replicate. =20
1000 X 10 (the difference in speed of DNA replication)=3D 10
000 or 10 =
to the 4
hmmmm by a rough calculation it makes sense why you have ~10 to
the 4 =
origins in the human genome and only 1 in bacteria.
To your suggestion of the nuclear membrane as a possible reason
higher replication rates I think the membrane provides a way of
segregating transcription and translation first of all and may
really have much to do with replication on a surface level. =20
dellaire at odyssee.net
More information about the Biochrom


The Impact of Religion Develops
Cardinal Georges Marie Martin Cottier who has officiated as religious affairs advisor for Pope in Vatican stated that the impact of the religion is increasing world wide. During his speech at The Religions and The Civil Authority Conference organized in Rome, he said: "In recent years, we bear witness a religious revival throughout the world. The impact of the religion increases while improving in a positive way thanks to the globalization. Considering the various identifications as reasons of conflict should not be allowed anymore."
2010-03-13 00:00:00
© 1994 Harun Yahya. -


text:
Continuing where we left off last time, today I want to present a few ideas about how to design the API that enables us to do stateless rendering.
Before we talk about how to design a stateless rendering API, let us quickly take a look at how a stateful rendering API usually performs its task.
Conventional, stateful rendering
This is the type of rendering everybody knows: you set a few states here and there, submit a draw call, set some states, submit a draw call, and so on.
Usually, this looks something like the following:
// 1) render first object backend::SetCullState(CULLSTATE_BACK); backend::SetVertexBuffer(vb); backend::SetIndexBuffer(ib); backend::BindTexture(0u, diffuse); backend::DrawIndexed(triCount*3, 0u, 0u); // 2) render second object backend::SetCullState(CULLSTATE_FRONT); backend::BindTexture(0u, otherDiffuse); backend::SetAlphaBlendState(ONE_ONE); backend::DrawIndexed(triCount*3, 0u, 0u);
The problem with that abstraction is that whatever state was set when rendering the first object also affects the rendering of the second object, which affects the rendering of the third object, and so on. State once set in the pipeline leaks into subsequent draw calls, and in case it isn't obvious, there are actually two problems (not just one!) with the stateful abstraction above:
- First problem: When rendering e.g. a third object, it will be rendered with a reversed culling state in case we forget to set it back to CULLSTATE_BACK. Same with alpha blending. This is the smaller of the two problems.
- Second problem: Whenever you have to change a state of some draw call, all following draw calls not touching the same state will now be broken. This is much worse than the first problem, because you either have to change all the draw calls you actually didn't want to touch, or always set back all touched upon states to their default values after a draw call has been submitted. This is both error-prone and tedious.
And we haven't even started talking about multi-threaded rendering yet.
To elaborate a bit on the second point, imagine what would happen if we changed the code above to the following:
// 1) render first object backend::SetCullState(CULLSTATE_BACK); backend::SetVertexBuffer(vb); backend::SetIndexBuffer(ib); backend::SetRasterizerState(NO_DEPTH_WRITE); // <=== backend::BindTexture(0u, diffuse); backend::DrawIndexed(triCount*3, 0u, 0u); // 2) render second object backend::SetCullState(CULLSTATE_FRONT); backend::BindTexture(0u, otherDiffuse); backend::SetAlphaBlendState(ONE_ONE); backend::DrawIndexed(triCount*3, 0u, 0u);
By introducing a new command SetRasterizerState that changes the state of the pipeline, all draw calls following the first one are also affected by our change, because the other draw calls never touch that state. We either have to set it explicitly in the second draw call, or reset it after submitting the first DrawIndexed. It's much worse when you want to move certain render operations from here to there, put them in a function, etc. because you always have to be aware of the "surrounding state". Like I said, error-prone and tedious.
Introducing a stateless API
Armed with the knowledge of what's clearly wrong with the stateful approach above, let us try to come up with better solutions. One possible solution would be to start from a clean default state each frame, and reset all the states back to their default whenever we submit a draw call. If the user were to do that himself, this could look like the following:
// at the beginning of a frame, all states are set to their default value // 1) render first object backend::SetCullState(CULLSTATE_BACK); backend::SetVertexBuffer(vb); backend::SetIndexBuffer(ib); backend::BindTexture(0u, diffuse); backend::DrawIndexed(triCount*3, 0u, 0u); backend::ResetDefault(); // <=== // 2) render second object backend::SetCullState(CULLSTATE_FRONT); backend::BindTexture(0u, otherDiffuse); backend::SetAlphaBlendState(ONE_ONE); backend::DrawIndexed(triCount*3, 0u, 0u); backend::ResetDefault(); // <===
Of course, we could also put that functionality into our API, and let it take care of that.
For now, let us assume that we have one big render queue which is used for queueing up all draw calls during a frame, which then get sorted and dispatched using the render backend at the end of a frame. Then we could do the following:
// 1) render first object renderQueue::SetCullState(CULLSTATE_BACK); renderQueue::SetVertexBuffer(vb); renderQueue::SetIndexBuffer(ib); renderQueue::BindTexture(0u, diffuse); renderQueue::SubmitIndexed(triCount*3, 0u, 0u); // 2) render second object renderQueue::SetCullState(CULLSTATE_FRONT); renderQueue::BindTexture(0u, otherDiffuse); renderQueue::SetAlphaBlendState(ONE_ONE); renderQueue::SubmitIndexed(triCount*3, 0u, 0u); // at the end of a frame: renderQueue::Sort(); renderQueue::Flush();
Basically, all our renderQueue implementation has to do is the following:
- Keep track of the currently set vertex buffer, index buffer, cull state, alpha state, texture samplers, etc. Whenever someone calls renderQueue::Set*State(), simply change the corresponding member to the new state.
- For each Submit*() call, insert a new draw call into the queue. Our queue in this case would be raw memory, and we would simply store the type of the operation (an indexed draw call), the key (used for sorting), and all data that goes along with the draw call (in our case all the current states). After that, we reset all our internal state members to their default value.
- Upon a call to Sort(), we simply sort all the keys using e.g. a radix sort.
- Upon a call to Flush(), we walk the sorted array of operations, fetch the type, fetch the data, and call the respective render backend functions. It's very similar to implementing a simple virtual machine.
Of course, there are many implementation details we haven't talked about yet, but that's basically the gist of it. However, there is one thing I really don't like about that approach, as soon as multi-threaded rendering enters the picture.
With multi-threaded rendering, we want to be able to call any renderQueue function from any thread, which means that even though the C++ code looks like sequential code, calls to various renderQueue::Set*() functions are made from different threads, and are therefore interleaved. We can no longer use simple members in our renderQueue implementation to keep track of the current state, and not even wrapping each function with a mutex (or similar) would work, because we would need to wrap all operations that belong to a single draw call at once. This has way too much overhead, don't even think about doing it this way.
There is of course a simpler, and faster solution to that: thread-local storage. Instead of keeping track of the currently set state using simple members in the renderQueue, each thread keeps track of its state using e.g. a thread-local struct which holds all the states.
However, I'm still not satisfied with such an approach, because it means that every renderQueue function call now has to access some thread-local variable, which adds overhead compared to just accessing memory. Therefore, I am also considering the following alternatives.
The first one boils down to creating structs holding the state for a draw call on the stack, and then copying all of it into the queue upon submitting a draw call, something like the following:
IndexedDrawCall dc; dc.SetVertexBuffer(mesh->vertexBuffer); dc.SetIndexBuffer(mesh->indexBuffer); dc.SetCullState(CULLSTATE_BACK); renderQueue::Submit(dc);
Firstly, this pretty much gets rid of all the multi-threading problems we have seen in the approach above. If we want to use one global queue, all we have to do is copy the data given in a call to renderQueue::Submit() (along with the key for sorting). For that, we can simply use a linear allocator that does nothing more than increment a pointer for each allocation. By using atomic operations, we can trivially make the allocation both thread-safe, and fast. If we don't want to use atomic operations, we can use a thread-local queue per thread instead.
Secondly, this would allow us to cache certain draw calls. For certain static parts of the world, we could build the draw call once, store it somewhere, and submit it into the renderQueue without any additional work.
Thirdly, each draw call like IndexedDrawCall, InstancedDrawCall, ComputeDrawCall, etc. could make sure to only store the data it needs, which could cut down on the amount of memory required to store the individual draw calls.
There are two things which I don't like with this approach, though:
- Each instance of a draw call struct is stateful again, which means that the user could create a draw call on the stack, submit


Saturday, November 3, 2012
Draw Multinomial Random Variables
Original Code
* It is a little tricky to draw multinomial random variables (joint binomial distribution) in Stata because Stata does not have a canned inverse CDF function for the binomial that inverts P values to x values.
* Fortunately in my last post I programmed an inverseCDF command (
* I will load in the program for later use:
cap program drop CDFinv
program define CDFinv
 * Let's define the arguments of the program.
 * N is the total number of trials.
 * P is the CDF value that we would like inverted
 * p is the probability of one outcome being a success.
 * newvar is the name of the new variable to be generated.
 args newvar P N p
 * The challenging thing about trying to invert a CDF for a count distribution is that the CDF is a probability mass function with discontinuous regions.
 * However, the particularly nice thing about the binomial distribution is the the pool of outcomes is well defined. (1,2,3..N)
 * Thus we can simply count how many times the "steps" of the CDF fall below the target CDF level.
 cap drop 'newvar'
 qui gen 'newvar'=0
 label var 'newvar' "Inverse CDF of binomial"
 forv k=1(1)'N' {
 * Add 1 to the variable value every time the CDF(n,k-1,p) is less than the target CDF value P.
qui replace 'newvar'='newvar'+1 if binomial('N', 'k'-1, 'p')<('P')
* This post also draws on a previous post in which I show how to transform Stata multivariate normal random draws into into any correlated random variable (
set more off
set obs 10000
* For instance let's draw four variables.
* 1. a chi2 with 5 degrees of freedom
* 2. a poisson k = 5
* 3. a uniform variable with min = -5 and max = 5
* 4. a random f distribution draw with 5 and 5 degrees for numerator and denominator degrees of freedom.
* First we will specify the correlation matrix.
* The only constraint as far as I know is that the covariance matrix has to be PSD.
* This in practicality limits the possible correlations between variables since cross terms tend to cause vialations more likely in the PSD requirement.
matrix c = ( 1,.9,.3, .2 \ ///
 .9, 1,.2, .1 \ ///
 .3,.2, 1, .5 \ ///
 .2,.1,.5, 1 )
* If we do not specify a mean or covariance matrix then the default draws are standard normals which is what we want for simplicity.
drawnorm x1 x2 x3 x4, corr(c)
corr x?
spearman x?
* Now all we need to do is turn our normal draws into uniform draws.
* Note: if x~N(0,1) and THETA is the CDF of the normal then y=CDF(x)~uniform
* So for any new distribution with CDF ALPHA and inverse INVALPHA the variable z=INVALPHA(y) ~ alpha.
gen y1 = normal(x1)
gen y2 = normal(x2)
gen y3 = normal(x3)
gen y4 = normal(x4)
corr y?
spearman y?
* Looking good. All of the y variables are uniformly distributed now while still maintaining most of the correlation and all of the rankcorrelation.
* The key final step is to take the inverse CDF of the uniforms for a series of binomial draws.
* The function CDFinv is programmed so that the:
* 1st argument is the new variable name to be created
* 2nd is the cumulative P value to be inverted
* 3rd Number of total draws
* 4th probability of success on each individual draw
* Let's imagine you would like to simulate quarterly data on verterans.
CDFinv z1 y1 4.05
 label var z1 "Hospitalization from mental illness"
CDFinv z2 y2 4.15
 label var z2 "Hospitalization from accident"
CDFinv z3 y3 4.2
 label var z3 "Seeks treatment for PTSD"
CDFinv z4 y4 1.2
 label var z4 "Unemployed"
corr z?
spearman z?
* Note: Using an inverse CDF function is highly non-linear. Thus the correlations are significantly weakened since only a linear transformation of the initial values would maintain the same correlation values.
* To adjust the final correlations, experiment with initial values until you find outcomes that approximate the level of correlation desired.
* It is worth noting that there is an upper limit to the amount of correlation possible as a result of this transformation.
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Baylor Study Finds People Primed With Christian Religious Words More Likely To Express Racial PrejudiceApril 6, 2010
First study to scientifically test the effect of religion on racial prejudice
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A Baylor University study that is the first to scientifically test the effect of religion on racial prejudice has found people primed with Christian concepts led to increased expression of racial prejudice and general negative views toward African-Americans.
The study appeared this week in the premier journal Social Psychological and Personality Science.
"What's interesting about this study is that it shows some component of religion does lead to some negative evaluations of people based on race. We just don't know why," said Dr. Wade Rowatt, associate professor of psychology and neuroscience at Baylor who led the study. "It could be that priming religious words activates cognitive representation of things like right-wing authoritarianism and a Protestant work ethic."
Priming occurs when an earlier stimulus influences a response or behavior to a later stimulus. For instance, when a person is primed with a list of words about furniture that does not include the word "table," a higher percentage of participants would complete a word stem starting with "tab," as in "table," than non-primed people. Another example is people primed with old-age stereotype words walked more slowly down a hall after an experiment than those primed with young-age stereotype words.
Baylor researchers subliminally primed college students with neutral and Christian concepts like "heaven," "faith" and "cross." The participants were asked to categorize words on a computer screen, however before each word appeared, the "prime" word would appear on the computer screen for less than a half second. After being primed, the participants' attitudes toward African-Americans were assessed using both subtle and overt measures. For instance, one experiment presented the participants with an argument for or against a particular social policy that would be beneficial or detrimental to African Americans. The participants then rated the degree to which the argument supported the conclusion, thus reporting their underlying overt feelings toward African-Americans.
To determine if both experimental groups were equivalent with regard to their degree of religiousness or spirituality, measures were administered a few days before the priming experiment. Religiousness and spirituality were also were measured so that these variables could be statistically controlled when analyzing the effect of priming on religion.
Rowatt and his team, led by Baylor graduate student Megan K. Johnson, found when the participants were primed with Christian religious concepts, it increased subtle and overt prejudice toward African-Americans. However, the Baylor researchers also found priming Christian concepts did not cause a shift in reported underlying emotion, such as increases in fear of African-Americans. These priming effects persisted when the researchers controlled for pre-existing levels of religiousness and spirituality.
Media contact: Frank Raczkiewicz, Assistant Vice President of Media Communications, _PHONE_.


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30 Things To Learn From Badass Historical Moms
Another Badass Historical Moms Tip: healthcare for all! in the 1800s?
Susan's own parents taught her to embrace her mixed race heritage, as they were of both Native American and the majority white world themselves. Susan went on to fully live this teaching when she became American's first female Native American physician, returning to her home reservation but doctoring all people, both white and Native. She advocated for all people to receive better healthcare.
It was said that, as a child, Susan once watched a tribal elder die because a white doctor refused to treat the elderly lady. She decided then that she could do the job better. When Susan married a man from a Sioux tribe, she continued breaking barriers. While bearing two children, Susan fought against traditional expectations and continued working professionally full time.


eTech & Art & More
SIGGRAPH is the premier conference for computer graphics. It brings together researchers, professionals, artists, students and teachers. The conference mission says among other things that SIGGRAPH presents "leading-edge theory and practice of computer graphics and interactive techniques". It is an intense week of technical wonders and old friends.
Here are a few reports on life at SIGGRAPH outside of the technical agenda.
Sake Party
Sights and Sounds: Sunday at SIGGRAPH
The Figueroa Hotel
International Scene
Ben's impressions
Food court at LACC
The exhibition (photo Frank Nocke)
You may have heard of the engineering concept, "MTBF," meaning Mean (or average) Time Between Failures. It's a commonly used measure of the expected number of hours a mechanism can work without requiring some sort of repair. A more important measure at SIGGRAPH is "MDBF," or Mean Distance Between Friends. This refers to the distance you can travel down a SIGGRAPH hallway without running into someone you know. As you attend more SIGGRAPHs, your MDBF in a SIGGRAPH hallway declines precipitously.
Since seeing someone you know requires initiating a conversation (however short) with them (see "Upgrading"), as your MDBF declines over the years, you become unable to move effectively around the conference. You need to plan ahead for the ten minute walk over to the panels room, which will take you 45-50 minutes due to MDBF issues. Eventually, you are reduced to standing in the lobby of the convention center, greeting friends and finding out from them what's happening at the conference you won't get inside to see.
See also: upgrading


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You are here: Home / News / Industry Encyclopedia / How to Solve the Fault of 10kV Distribution Line?
How to Solve the Fault of 10kV Distribution Line?
Views:254 Author:Site Editor Publish Time: 2020-09-04 Origin:Site
The distribution line is the terminal of the power transmission and distribution system, which is also an important part of the power system. Some practical situations, such as the impact of the external environment and climate, will directly affect the power supply and production of the outside world and the safety of the livelihood. Although many factors are causing 10kV line fault, they can be detected by advanced electric wire fault indicator monitoring system and accurate cable fault indicator. It can be divided into three types of faults from nature: single-phase grounding fault, grounding phase to phase short-circuit fault, and phase to phase short-circuit fault.
accurate cable fault indicator
Lightning Fault
As lightning is an uncontrollable natural phenomenon and its instantaneous overvoltage has a strong destructive power to the entire 10kV line, so the fault caused by lightning in summer accounts for a large proportion of 10kV line fault. Also, it is easy to threaten safety in the leakage accident when a lightning fault occurs because it will damage the relevant facilities and equipment. Therefore, it is worth taking measures to install the reliable cable fault indicator monitoring system. Although all kinds of buildings in the city are generally equipped with lightning rods and some lightning protection measures, cable faults still occur frequently, which require maintenance workers to use advanced cable fault passage indicators as soon as possible in recent years.
External Force
Since 10kV lines are directly oriented to end-users and the line network is relatively complex, it is very easy to cause faults caused by external force damage, mainly including faults caused by foreign matters.
The fault caused by bird damage mainly refers to the phase to phase short circuit fault caused by birds nesting and stopping on 10kV lines.
Equipment damage fault is mainly about the whole line fault due to the incorrect use of electrical appliances or automated overhead line fault indicator damage.
Due to the acceleration of urban-rural integration, the depth, and scope of infrastructure construction in the urban-rural fringe are becoming more and more extensive. Therefore, the underground cable laying, digital AC DC voltmeter indicator, and other power facilities are often damaged during construction.
Equipment Failure
Due to the wide coverage, complex operation line, too many branches, aging reliable electric wire fault passage indicator, long line diameter, long-term reconstruction, incomplete corridor clearance, alternation of seasons, and serious aging of related equipment, the equipment fault itself will also cause 10kV line operation obstacles. Besides, some of the old equipment in the electricity room has potential safety hazard, so the backward automated cable fault indicator and the lack of daily management of special personnel are easy to cause the 10kV power line trip.
 reliable electric wire fault passage indicator
Management and Maintenance Failure
Poor daily management and maintenance will also cause a 10kV line fault. For example, the inspection is not strict, the quality is not up to standard, or the installation level is insufficient in the purchase of advanced cable fault passage indicators. Besides, it is very easy to cause a fault trip in a long drought or light rain because the chemical and mining dust is easy to accumulate on the digital cable fault passage indicator and other electrical equipment.
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Globalization of Water: Sharing the Planet's Freshwater Resources
January 2008, Wiley-Blackwell
This price is valid for United States. Change location to view local pricing and availability.
Other Available Formats: E-book
Globalization of Water is a first-of-its-kind review of the critical relationship between globalization and sustainable water management. It explores the impact of international trade on local water depletion and pollution and identifies "water dependent" nations.
- Examines the critical link between water management and international trade, considering how local water depletion and pollution are often closely tied to the structure of the global economy
- Offers a consumer-based indicator of each nation's water use: the water footprint
- Questions whether trade can enhance global water use efficiency, or whether it simply shifts the environmental burden to a distant location
- Highlights the hidden link between national consumption and the use of water resources across the globe, identifying the threats facing 'water dependent' countries worldwide
- Provides a state-of-the-art review and in-depth data source for a new field of knowledge


There are three random variables, $x,y,z$. The three correlations between the three variables are the same. That is,
What is the tightest bound you can give for $\rho$?
 - 1
 $\begingroup$ Presumably by "pho", you mean rho ($\rho$). However, your question is not clear. What do you mean by "What's the tightest bound you can give"? $\endgroup$ – gung - Reinstate Monica Oct 15 '13 at 1:57
 - $\begingroup$ Well the name of the variable is just a dummy. By tightest bound, I mean something like [-1, 1] for a correlation, but this clearly isn't the tightest possible bound. $\endgroup$ – user1352399 Oct 15 '13 at 2:08
 - $\begingroup$ Do you mean that rho=cor(x,y)=cor(x,z)=cor(y,z), and what are the limits for rho? $\endgroup$ – user31264 Oct 15 '13 at 2:23
 - $\begingroup$ Yes I mean that rho=cor(x,y)=cor(x,z)=cor(y,z) and what are the limits for rho. Dilip, can you extend that to say that rho must be non-negative, ie >= 0? $\endgroup$ – user1352399 Oct 15 '13 at 2:44
 - 1
 $\begingroup$ A textbook to cite for this is Seber & Lee "Linear Regression Analysis" (At least it was in first edition...) $\endgroup$ – kjetil b halvorsen Nov 27 '18 at 18:46
The common correlation $\rho$ can have value $+1$ but not $-1$. If $\rho_{X,Y}= \rho_{X,Z}=-1$, then $\rho_{Y,Z}$ cannot equal $-1$ but is in fact $+1$. The smallest value of the common correlation of three random variables is $-\frac{1}{2}$. More generally, the minimum common correlation of $n$ random variables is $-\frac{1}{n-1}$ when, regarded as vectors, they are at the vertices of a simplex (of dimension $n-1$) in $n$-dimensional space.
Consider the variance of the sum of $n$ unit variance random variables $X_i$. We have that $$\begin{align*} \operatorname{var}\left(\sum_{i=1}^n X_i\right) &= \sum_{i=1}^n \operatorname{var}(X_i) + \sum_{i=1}^n\sum_{j\neq i}^n \operatorname{cov}(X_i,X_j)\\ &= n + \sum_{i=1}^n\sum_{j\neq i}^n \rho_{X_i,X_j}\\ &= n + n(n-1)\bar{\rho} \tag{1} \end{align*}$$ where $\bar{\rho}$ is the average value of the $\binom{n}{2}$correlation coefficients. But since $\operatorname{var}\left(\sum_i X_i\right) \geq 0$, we readily get from $(1)$ that $$\bar{\rho} \geq -\frac{1}{n-1}.$$
So, the average value of a correlation coefficient is at least $-\frac{1}{n-1}$. If all the correlation coefficients have the same value $\rho$, then their average also equals $\rho$ and so we have that $$\rho \geq -\frac{1}{n-1}.$$ Is it possible to have random variables for which the common correlation value $\rho$ equals $-\frac{1}{n-1}$? Yes. Suppose that the $X_i$ are uncorrelated unit-variance random variables and set $Y_i = X_i - \frac{1}{n}\sum_{j=1}^n X_j = X_i -\bar{X}$. Then, $E[Y_i]=0$, while $$\displaystyle \operatorname{var}(Y_i) = \left(\frac{n-1}{n}\right)^2 + (n-1)\left(\frac{1}{n}\right)^2 = \frac{n-1}{n}$$ and $$\operatorname{cov}(Y_i,Y_j) = -2\left(\frac{n-1}{n}\right)\left(\frac{1}{n}\right) + (n-2)\left(\frac{1}{n}\right)^2 = -\frac{1}{n}$$ giving $$\rho_{Y_i,Y_j} = \frac{\operatorname{cov}(Y_i,Y_j)}{\sqrt{\operatorname{var}(Y_i)\operatorname{var}(Y_j)}} =\frac{-1/n}{(n-1)/n} = -\frac{1}{n-1}.$$ Thus the $Y_i$ are random variables achieving the minimum common correlation value of $-\frac{1}{n-1}$. Note, incidentally, that $\sum_i Y_i = 0$, and so, regarded as vectors, the random variables lie in a $(n-1)$-dimensional hyperplane of $n$-dimensional space.
 - $\begingroup$ I'm a little confused by this answer. I think it correctly shows that the p >= -1/(n-1) bound is necessary and sufficient for the variance of a sum of variables to be non-negative, but it doesn't seem to actually be necessary and sufficient for positive-definiteness of the correlation matrix in general. $\endgroup$ – user49404 Feb 3 '20 at 19:08
 - 1
 $\begingroup$ _USER_ Correlation matrices don't need to be positive definite; only positive semidefiniite (also called nonnegative definite by some people). Also, the OP's question only asked for a bound on the minimum value of the common correlation of the (three) variables and not about correlation matrices in general. Be that as it may, see this answer of mine for the general result. $\endgroup$ – Dilip Sarwate Feb 4 '20 at 17:37
The tightest possible bound is $-1/2 \le \rho \le 1$. All such values can actually appear--none are impossible.
To show there is nothing especially deep or mysterious about the result, this answer first presents a completely elementary solution, requiring only the obvious fact that variances--being the expected values of squares--must be non-negative. This is followed by a general solution (which uses slightly more sophisticated algebraic facts).
Elementary solution
The variance of any linear combination of $x,y,z$ must be non-negative. Let the variances of these variables be $\sigma^2, \tau^2,$ and $\upsilon^2$, respectively. All are nonzero (for otherwise some of the correlations would not be defined). Using the basic properties of variances we may compute
$$0 \le \text{Var}(\alpha x/\sigma + \beta y/\tau + \gamma z/\upsilon) = \alpha^2 +\beta^2+\gamma^2 + 2\rho(\alpha\beta+\beta\gamma+\gamma\alpha)$$
for all real numbers $(\alpha, \beta, \gamma)$.
Assuming $\alpha+\beta+\gamma\ne 0$, a little algebraic manipulation implies this is equivalent to
$$\frac{-\rho}{1-\rho} \le \frac{1}{3} \left(\frac{\sqrt{(\alpha^2+\beta^2+\gamma^2)/3}}{(\alpha+\beta+\gamma)/3}\right)^2.$$
The squared term on the right hand side is the ratio of two power means of $(\alpha, \beta, \gamma)$. The elementary power-mean inequality (with weights $(1/3, 1/3, 1/3)$) asserts that ratio cannot exceed $1$ (and will equal $1$ when $\alpha=\beta=\gamma\ne 0$). A little more algebra then implies
$$\rho \ge -1/2.$$
The explicit example of $n=3$ below (involving trivariate Normal variables $(x,y,z)$) shows that all such values, $-1/2 \le \rho \le 1$, actually do arise as correlations. This example uses only the definition of multivariate Normals, but otherwise invokes no results of Calculus or Linear Algebra.
General solution
Any correlation matrix is the covariance matrix of the standardized random variables, whence--like all correlation matrices--it must be positive semi-definite. Equivalently, its eigenvalues are non-negative. This imposes a simple condition on $\rho$: it must not be any less than $-1/2$ (and of course cannot exceed $1$). Conversely, any such $\rho$ actually corresponds to the correlation matrix of some trivariate distribution, proving these bounds are the tightest possible.
Derivation of the conditions on $\rho$
Consider the $n$ by $n$ correlation matrix with all off-diagonal values equal to $\rho.$ (The question concerns the case $n=3,$ but this generalization is no more difficult to analyze.)


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Free Project Booklet: Group Afghan
This PDF was originally intended for UK schools but the methods are equally useful to any knitters wanting to work together on a project. It was originally produced in booklet form and has been used in many countries around the world. It was written with children in mind and has proved to be equally acceptable to adults.
The main aim of the booklet was to use mathematics in a 'nonthreatening' way so, in addition to the knitting information, it also includes ideas for use in mathematics lessons.
See some of the afghans made in schools, and read about teachers' experiences. and the work of the Cheshire Women's Institute, based on the same booklet.
The photos show three very different afghans created from the same instructions, one from Cheshire WI, the others from schools.
The pattern is free but we would like you to consider making a donation to Kidney Research UK, where we have set up a page in memory of my parents. For more information, see the Tribute Page on the Woolly Thoughts web site.


text:
This study has shown how the forms of social interaction differ for each player type in the social trivia game Buzz! Quiz World, from the taunting of highly competitive killers, the boasting of achievers, or the collaborative discussion of socializers. The application of this to different game types, from FPSs to RPGs, would reveal interesting distinct traits in the interactions found among each player type in response to more directly competitive play. There is also potential to explore how social interaction changes among larger groups of players.
With a more robust understanding of different gaming cultures and spaces, maybe gamers can then have a better sense of what, exactly, they're getting themselves into next time someone screams "HEADSHOT!"