Dataset Viewer (First 5GB)
content
stringlengths 21
668k
| pred_label
stringclasses 1
value | pred_score
float64 0.7
1
|
|---|---|---|
Front Cover
Dorling Kindersley, Sep 1, 2000 - Juvenile Nonfiction - 59 pages
26 Reviews
The story of Titanic's tragic maiden voyage still tugs at the heartstrings and sparks universal curiosity--Eyewitness Titanic discovers the story behind the story. From a Belfast shipyard to the ship's death in the icy Atlantic, the story comes alive through 30D renderings, photographs, and deck plans. Eyewitness Titanic is a compelling narrative of courage and cowardice, sacrifice and survival. See the wreck on the ocean floor, the Titanic's gigantic propeller, and the ship's luxurious interior. Learn how the survivors were rescued from the icy waters and how the shipwreck was located. Discover what caused the "unsinkable" Titanic to sink, the preservation techniques of underwater archeology, and much, much more.
From inside the book
What people are saying - Write a review
User ratings
5 stars
4 stars
3 stars
2 stars
1 star
The book has many good illustrations. - Goodreads
SO sad, there all these pictures of people that died. - Goodreads
detailed pictures of objects, artifacts, and research. - Goodreads
Review: Titanic
User Review - Goodreads
detailed pictures of objects, artifacts, and research.
Review: Titanic
User Review - Goodreads
1. Simon Adam 2. 1/9=40 minutes 1/11=50 minutes 3. safety, hit, ice-burg, selfish, boat, shortage, emergency 4. Q. In this story, a few people who rode on a ship, Titanic were exposed to emergency of ...
Related books
Common terms and phrases
About the author (2000)
Simon Adams edited childrenas reference books and other nonfiction books before turning to full-time writing. He is the author of more than 50 books for children on a wide variety of subjects, including history and jazz. He lives in London.
Bibliographic information
|
__label__pos
| 0.981076 |
1. NOOK Sample
Go Back
You've Reached the End of Your Sample
The Scarlet Letter
Customers Who Bought This Also Bought
1. The Count of Monte Cristo (abridged) (Barnes & Noble Classics Series)
2. Sarah's Key
3. The Adventures of Tom Sawyer
4. The Importance of Being Earnest
|
__label__pos
| 0.994898 |
Forgot your password?
I, Carmelita Tropicana: Performing Between Cultures Test | Final Test - Hard
Alina Troyano
Purchase our I, Carmelita Tropicana: Performing Between Cultures Lesson Plans
Final Test - Hard
Name: _____________________________ Period: ___________________________
Short Answer Questions
1. Which book is Carmelita reading?
2. What is the name of Juana's slave?
3. The goddess is from which culture?
4. What item of the mugger's clothes is mentioned?
5. Who is the soldier mentioned in the Conquest of Mexico?
Essay Topics
The Dictator calls Carmelita regarding the activities in downtown Manhattan. What type of activities took place in Manhattan? Who participated? What were the consequences of the activities? Who arranged the activities? Who is the Dictator? How was s/he involved? What was the relationship between the Dictator and Carmelita? What happened to the Dictator after the raid? Did the Dictator and Carmelita have any contact after Carmelita's arrest or incarceration in BMU? Explain.
After being arrested for participating in the protest, Carmelita, Desiree, Orchidia, Sophia and others were arrested and sent to the Behavioral Modification Unit. What is the BMU? Where is it located? What is the purpose of the unit? How does it relate to the government? What kind of activities occur at the BMU? Is it a prison? What types of crimes must one commit to be sent to the unit? What is the DNA Remodeling Action? Can someone's DNA be remodeled? If so, how? What types of programs are the inmates required to complete?
Carmelita worked at the Tropicana in Havana before going to the United States. After Carmelita arrived in the United States she opened a similar nightclub, also called the Tropicana, in Manhattan. What types of nightclubs were the Tropicanas? Compare and contrast the two clubs. What were the biggest similarities? Did Carmelita operate both nightclubs? What happened to each club? Who was involved in the destruction of at least one of the clubs? Explain.
(see the answer keys)
This section contains 303 words
(approx. 2 pages at 300 words per page)
Purchase our I, Carmelita Tropicana: Performing Between Cultures Lesson Plans
I, Carmelita Tropicana: Performing Between Cultures from BookRags. ©2009 BookRags, Inc. All rights reserved.
Follow Us on Facebook
|
__label__pos
| 0.985478 |
Enter your Everyday Health log-in here:
E-Mail Address:
Forgot Your Password?
Ask Dr. Stuart Stark
Can Heart Medications Prevent Migraines?
Medically reviewed by Ed Zimney, MD
Q: Can a cardioselective beta-blocker prevent migraines?
Yes. The entire class of medications, called beta-blockers, is used to prevent migraine headaches and has been proven effective. These are drugs originally developed to treat high blood pressure and are also used to treat anginaand prevent heart attacks. The difference between selective and nonselective beta-blockers has to do with which beta receptors the medication targets. Selective beta-blockers inhibit the beta-1 receptor, located in the heart and kidneys. Nonselective beta blockers inhibit both beta-1 and beta-2 receptors, located in the lungs, gastrointestinal tract, blood vessels and other places.
The decision to prescribe a nonselective beta-blocker, such as Inderal (propranolol) versus a selective one, such as Lopressor (metoprolol), is based on the patient’s complete medical and medication history. For example, nonselective beta-blockers should not be prescribed to anyone with a history of asthma, since they are much more likely to exacerbate asthma compared to the selective beta-blockers.
Last Updated: 05/05/2008 | Last Reviewed: 05/05/2008
Dr. Stuart Stark is the medical director of the Neurology and Headache Treatment Center in Alexandria, Virginia.
Explore Everyday Health
|
__label__pos
| 0.818727 |
A Little Climate Change Goes a Long Way in the Tropics
In hot places, minor warming could rev up metabolism in animals that don’t generate their own heat.
By Susan Milius, Science News
While biologists worry primarily about global warming’s effects on life in the Arctic, a seemingly paradoxical result of climate change may be sneaking up on metabolically sensitive creatures in the tropics.
Temperatures in the Arctic have climbed upward faster than in low latitudes. Yet a quirk of physiology could mean that slight upticks in the tropics are delivering a disproportionate jolt to some residents, says Michael Dillon of the University of Wyoming in Laramie. Insects, soil bacteria, frogs, salamanders, lizards, snakes and other animals that warm and cool with their surroundings could be getting a major kick in the metabolism from even slight rises in temperature.
For these organisms—the ectotherms—warming up more means speeding up the metabolic pace of life. And Dillon points out that temperature drives metabolism exponentially, delivering way more of a buzz at higher temperatures than at low ones.
Combining established principles of physiology with some 500 million temperature records, Dillon and his colleagues calculated how much the temperature changes in four broad regions may have pepped up local ectotherms. Since 1980, the changes calculated for metabolic rates in the tropics are at least double those in the Arctic, Dillon and his colleagues report in the Oct. 7 Nature.
“It’s taken a while for people to start applying the thinking of climate change to the tropics,” says tropical ecologist Catherine Cardelús. At first biologists tended to dismiss tropical organisms as already highly adapted to heat, says Cardelús, of Colgate University in Hamilton, N.Y. But a growing number of studies are showing that ecology is far from that simple.
Dillon speculates that sped-up ectotherms in the tropics might become more vulnerable to starvation if resources can’t keep pace, he speculates. “If you’re burning more energy, you need more energy,” Dillon says. Food webs may shift. Soil respiration may increase. Mosquitoes may breed faster.
Also, in the tropics, Dillon says, “the potential for big impacts on a global scale is the highest there simply because the biodiversity is the highest.”
He and his colleagues started with ideas from decades of physiology research that show exponential increases in metabolism as temperature climbs. Warming an ectotherm from 15° Celsius to 20° C might not increase metabolic rate much, Dillon says. But dial up the heat from 25° C to 30° C—the same number of degrees—and “metabolic rate could just shoot through the roof.”
To see how that effect might play out with climate warming, the team sorted through weather records to find stations that have taken at least six daily readings year-round since 1961. Data from these 3,186 stations showed Arctic temperatures rising by roughly 1.5 degrees Celsius on average since 1980 while tropical sites barely sloped upward, failing to reach even a 0.5 degree change overall.
To see what those shifts do to metabolism, the researchers tweaked a basic physiological equation to create four versions, one each to represent a generalized single-celled organism, an invertebrate, an amphibian or a reptile. For each of the millions of temperature records, researchers calculated metabolic rates for each of the four groups.
Based on these calculations, warming could hit low-latitude ectotherms harder than high-latitude ones. Arctic temperature increases could double those in the tropics, and metabolic changes in each region’s ectotherms would still be about equivalent.
Dillon cautions that plenty of real ectotherms have some ability to moderate their temperatures through behavior, such as darting under rocks to escape the sun. These measures have limits though, especially for small creatures, and actual biology—not just temperature—needs investigating.
“You can’t assume that the temperature patterns tell you what the effects on biology will be,” he says.
Follow U.S. News Science on Twitter.
|
__label__pos
| 0.840922 |
United States
North America
South America
Search Results: Knowledge Sheets on ''divinity'
Back - Topicwise Knowledge Sheets
Nimit - instrument of the divine
When you are neither clear nor confused, only then can you be a perfect instrument of the Divine! How would an instrument know what is going to be, and when? How can an instrument be confused, and how can an instrument be clear! This state is called......Read More
Let the wind that blows be sweet Let the oceans flow honey Let all the herbs and plant kingdom be favourable to us Let the nights be sweet and let the days be sweet Let the dust of this planet be sweet to us Let the heavens......Read More
Divine in the Form and Formless
Devotee Becomes God
When a river meets the ocean, the river no longer remains a river. It becomes the ocean. A drop of the ocean is part of the ocean. In the same way, the moment a devotee meets (surrenders to) the Divine, the devotee becomes GOD. When the river meets the......Read More
Search Wisdom
Please Enter Some Text
|
__label__pos
| 0.815869 |
Sentence for Intrigue?
The word intrigue as a verb is definedto arouse the curiosity or interest of or fascinate. As a noun, intrigue means the secret planning of something illicit or detrimental to someone. One example of using intrigue as a verb in a sentence might be, The administration of George W. Bush was scarred by years of intrigue and corruption during the Iraq war. An example of using intrigue as a verb would be, This book piqued my intrigue about politics.
Q&A Related to "Sentence for Intrigue?"
She saw the birds every single day, but they were somehow still intriguing.
Did you mean Intrigue? Here is a sentence using the word intrigue. As they work
You intrigue me because you come off as mysterious.
The best thing to do is start right before something happens in the story. You mentioned leading up to the main events, so that makes me think that you're making the classic beginner's
Explore this Topic
Intrigue can be used in sentences. It is intriguing to note that the standpoints in these two photographs vary only slightly. I was, and I'm sure that by now you're ...
And with a delicious buffet and glass of wine thrown in, what more could you want? And there's a special themed buffet once a week to add a little intrigue. The ...
|
__label__pos
| 0.993172 |
Forgot your password?
Louis Giannetti
Purchase our Flashback: A Brief History of Film Lesson Plans
Final Test - Medium
Name: _____________________________ Period: ___________________________
Multiple Choice Questions
1. What was the focus of Russian documentaries after World War II, as ordered by Stalin?
(a) Historical dramas.
(b) Sweeping epics.
(c) Entertainment.
(d) Russian nationalism.
2. At the end of the 1950s, how many homes in America had a television set?
(a) 95%.
(b) 55%.
(c) 75%.
(d) 85%.
3. During Japan's Golden Age in cinema, what country, previously considered a strong force in cinema, began to decline?
(a) Sweden.
(b) Britain.
(c) United States.
(d) France.
4. Which European country's film industry was the most devastated after World War II?
(a) Italy.
(b) Greece.
(c) Germany.
(d) Spain.
5. Due to the cinema's reflection of the American public's distrust of the government, what began to happen to the movie theater?
(a) Attendance declined.
(b) Security had to be enforced in the theater.
(c) Theaters became segregated.
(d) Attendance rose.
Short Answer Questions
1. What event in the sixties shifted the American film industry's focus?
2. What was significant about cinema in education in the 1970s?
3. What country nearly wiped out the French film industry after World War II?
4. For what reasons did filmmakers simplify camera work in the 1980s?
5. What was significant about the economy in American films during the early to mid-eighties?
(see the answer keys)
This section contains 271 words
(approx. 1 page at 300 words per page)
Purchase our Flashback: A Brief History of Film Lesson Plans
Flashback: A Brief History of Film from BookRags. ©2009 BookRags, Inc. All rights reserved.
Follow Us on Facebook
|
__label__pos
| 0.99357 |
March 15, 2014
Homework Help: Math help
Posted by Rachel on Wednesday, July 23, 2008 at 3:47pm.
Help with any of these would be greatly appreciated! THANK YOU!
1. How would i solve 3x^2 - 4 = 0?
And in simplest radical form?
2. How would i determine the values of 'k' if the graph y=2x^2-2x+3k intersects the x-axis at two distinct points?
3. The path of a basketball can be modeled by the equation h(d)=-0.13d^2+d+2. where h(d) is the height in meters or the basketball and d is the horizontal distance in meters from the player. How far does the ball travel horizontally before hitting the floor?
4. How would i solve x^3-3x^2+2=0?
How would i show it in exact values?
5.One of the zeros if P(x)=6^3-13^2+x+k is 2.
What would be the value of k?
And how would i write P(x) in factored form?
6. How would i solve |x| (greater than or equal to) |x - 3| using my graphing calc. What are the steps?
7. What would be the diameter of the largest circle possible that could be drawn between the parallel lines of y = 2x and y = 2x - 5?
Answer this Question
First Name:
School Subject:
Related Questions
algebra - 1.what is the simplest form of the producy sqrt 50x^7y^7 * sqrt 6 xy^4...
Math help - How would i solve 3x^2 - 4 = 0? And in simplest radical form?
Algebra 1 - Please help me find the answer to this problem. it would be nice to ...
Algebra - (3x+4)/(3x-4)+(3x-4)/(3x+4) --------------------------- Divide top by ...
Math - Find the domain of the following functions. 1. y= radical(x-3) - radical(...
math,correction - Problem #1 subtract. Express your answer in simplest form (3x...
|
__label__pos
| 0.999756 |
Display caption
The north-west passage was the unnavigable sea route round North America which was thought to provide a passage to the East. In time, it became synonymous with failure, adversity and death, with men and ships battling against hopeless odds in a frozen wilderness. Millais painted this picture in 1874 when another English expedition was setting off. Previous representations had shown had explored the desolate beauty of the terrain with details such as wrecked ships to underline the futility of man’s ambition. Millais encapsulates the risks of such a voyage primarily through the old seaman, with his grim, distant look and clenched fist.
March 2010
|
__label__pos
| 0.934009 |
2. All populations are rounded. Blank populations indicate unknown or very small populations. People groups with populations shown as unknown or less than 500 may have been assimilated into surrounding groups and can no longer be identified on the ground.
4. Certain percentages display as '0.00%' because of space limitations, but some may be slightly greater than zero. The exactness of numbers presented here can be misleading. Numbers can vary by several percentage points or more.
5. Discrepancies may exist between "Progress Indicators" because of the varying sources of information. Joshua Project does not have specific ministry activity data supporting each of the "Progress Indicators."
6. The Joshua Project Progress Scale is an approximation of church planting progress based on available progress indicators. For more details, click here. Please contact us if you have additional information.
8. Bible translation status: : 0=Questionable Need, 1=None, Definite Need, 2=Portions, 3=New Testament, 4=Complete Bible.
|
__label__pos
| 0.824752 |
Cinquain Poems?
A cinquain poem is a five line poem that describes a person, place, or thing. The first line is a one word title, a noun that tells what the poem is about. The second line contains two adjectives that describe the word in the first line. The third line contains three words ending in -ing that describe the noun in the first line. The fourth line contains a four word phrase that describes the noun from the first line. The fifth line contains only one word, a synonym for the noun in the first line.
1 Additional Answer Answer for: cinquain poems
The cinquain is a poem or stanza composed of five lines. The most common rhyme schemes are ababb, abaab and abccb.
Adelaide Crapsey, an early twentieth-century poet, used a form of 22 syllables distributed among the five lines in a 2, 4, 6, 8, and 2 pattern, respectively.
Other Forms:
Q&A Related to "Cinquain Poems?"
A limerick is a usually humorous verse with only five lines. The last word of lines one, two, and five must rhyme with each other, and the last word of lines three and four, which
1. Think of a person (or interview someone new) for the initial cinquain. Once you are familiar with the format, you could try writing one about a pet or item in nature. 2. Record
What is especially great about a cinquain poem is that they can express a lot with just five structured lines. Each line of a cinquain has a specific purpose and instruction for writing
1 Deci
Explore this Topic
A cinquan poem is a short poem that consists of only five lines. The first line is one word (the title), line 2 is two words that describe the title, line 3 is ...
A cinquain poem always have five lines. Within this pattern, there are several types of cinquain poems. Cinquain poems are a good form to teach to kids since they ...
A cinquain is a five-line poem that was invented by Adelaide Crapsey. One of the most famous cinquain poems is entitled, Silent Hearts. The poem reads; inside, ...
|
__label__pos
| 0.999785 |
How Many Pounds are in 1 Ton?
There are two different types of tons. There is a short ton, which contains 2000 pounds. Then you have a long ton. A long ton contains 2240 pounds.
1 Additional Answer Answer for: how much is 1 ton in pounds
One ton is equal to 2,000 pounds.
Convert to
Q&A Related to "How Many Pounds are in 1 Ton?"
There are 2,000 pounds in 1 ton.
1 ton is equal to 1000 pounds.
A short ton is 2000 pounds, a long ton is 2,240 pounds, & a metric ton is 1,000 kg or 2,205 lbs. Cool!
Explore this Topic
There are three similar units of mass called the ton. a) 1 Long ton, (aslo weight ton or gross ton) is is 2,240 pounds; b) 1 Short ton (aslo net ton) equals 2000 ...
1.5 tons is 3000 pounds. ...
A ton, also known as a short ton, is a unit of measure to determine the weight or volume of an item. In general, a ton is equivalent to 2,000 pounds. A long ton, ...
|
__label__pos
| 0.995745 |
The topic Khandhaka is discussed in the following articles:
place in “Vinaya Piṭaka”
• TITLE: Vinaya Piṭaka (Buddhist canon)
2. Khandhaka (“Divisions”; Sanskrit Vinaya-vastu, “Vinaya Subjects”), a series of 22 pieces (at least in the Pāli version) dealing with such matters as admission to the order; monastic ceremonies; rules governing food, clothing, lodging, and the like; and procedures for handling offenses and disputes. As in the...
• TITLE: Buddhism (religion)
SECTION: The Pali canon (Tipitaka)
|
__label__pos
| 0.916635 |
Impact of the abolition of EU Milk quotas on Agriculture in the UK
European Association of Agricultural Economists, 107th Seminar, January 30-February 1, 2008, Sevilla, Spain 01/2008;
Source: RePEc
ABSTRACT In recent years the CAP has undergone significant reforms, but the dairy sector has largely avoided wholesale changes. The sector, however, is now faced with a significant effort by the Commission to instigate reform. In this study the FAPRI-UK modelling system is simulated to identify the impact of abolishing or phasing out EU milk quotas on the dairy sector in the UK and the results are compared against a 2007 Baseline projection (2007--2016). The results demonstrate that although the impact of the abolition of dairy quotas is fairly modest at the EU-25 level, significant impacts are apparent at the individual country level.
0 0
|
__label__pos
| 0.924237 |
First: Mid: Last: City: State:
Erick Pliler
To help you locate the correct Erick Pliler, we'll utilize any data that we have in our records. Identify the exact Erick by using details such as previous residences and known aliases. Explore more personal details, including background checks, criminal profiles, and email addresses on USA-People-Search.com. If this Erick is not the person you are seeking, refer to the list of people with the last name Pliler below. This list could include name, age, location, and relatives.
Use additional details into the search fields on the left for improved results. A first name, middle name, last name, city, state and/or age can be the missing piece to finding Erick Pliler. To pinpoint and get a visual sense of their whereabouts, go ahead an make use of the map. When you locate the Erick Pliler you're seeking, you can then browse all the public records data we have in our comprehensive database. Get people search results for Erick Pliler in no time at all with our user friendly tools.
Name/AKAsAgeLocationPossible Relatives
|
__label__pos
| 0.709324 |
Telling Sentence?
When learning the English language, one of the most important aspects is understanding the different options and styles of sentences. One of the most common types of English sentence is called a telling sentence. These types of sentences are used when there is a need to tell someone something. Telling sentences always make a very specific and clear statement and will always end with a period, rather than an exclamation point or a question mark.
Q&A Related to "Telling Sentence?"
1. Ask how. Examine the phrase "He speaks slowly. The word "slowly" answers the question of how he speaks. Usually, adverbs that tell how end in -ly. 2. Determine if
The telling part of a sentence is the verb of the sentence. It is was the subject or noun is doing in the sentence.
A telling sentence is a sentence that has force and produces a striking effect.
The telling part of a sentence is the part of the sentence that starts with the verb, and tells what is happening to what or whom the sentence is about.
Explore this Topic
The telling part of a sentence is the verb. A verb is the most important part of a sentence because it asserts something about the subject, express action, events ...
You can tell whether a mathematical sentence is or is not an open sentence by determining if there is or is not one or more variables in it and that no truth value ...
If a mathematical sentence is open, it cannot be labeled as true or as false. It will have one or more variable in the sentence which will need to be subsituted ...
|
__label__pos
| 1 |
Pre-writing skills for children under five - PDF
Document Sample
Pre-writing skills for children under five - PDF Powered By Docstoc
Pre-writing skills for children under five
Dianne Saunders
All too often, young children are given writing tools to use before
they are ready for them. Young children from three to five years of age
use their hands to explore and learn about the environment and them-
selves. By developing good hand skills and other pre-writing skills you
will prepare your child for the next step, which is writing. Working on
hand skills will also assist older children who are experiencing writing
What are the pre-writing skills?
Hand skills refer to the strength and the dexterity (how well we can
handle small objects) in our hands. Both depend on how we use the
small muscles of our hands. However, we also need the muscles in our
forearm to provide strength and stability. In fact, we often must coordinate and use both types of muscles to do
things such as holding and using a pencil, using scissors, managing buttons, handling coins and using various
utensils for eating. The thumb, index and middle fingers carry out the skilled movements while the ring and baby
fingers provide stability and increase strength. It is also important to develop strength and control in the upper
body and shoulders so we can steady ourselves. This gives us the freedom to use our hands to manipulate and
control objects in a very precise manner.
Good sensory information is important for hand skills, as it tells our brain what we feel, how we move and
where our hands are as we do a task. The brain must coordinate these sensations with what we see so we can make
small changes for precise coordination and muscle control. Imagine you are wearing a pair of heavy gloves and
blurred glasses while you try to do your work. You would have difficulty coordinating your movements for most
tasks! Children need to receive and coordinate accurate sensory information when developing pre-writing skills.
Here are some suggestions to help your child develop good pre-writing skills:
General tips
|
__label__pos
| 0.995602 |
Strawberry Panachee
By PanNan on May 16, 2005
25 Characters Max
Enter Time:
You can create up to five timers
1. 2 1/2 cups ripe strawberries, hulled ( or other fresh berries)
2. 1/4 cup strawberry jam ( or raspberry or currant jam)
3. 4 shortbread cookies ( or other cookies like almond cookies)
4. 2/3 cup creme fraiche, divided ( or sour cream, or quark)
5. 4 sprigs fresh mint ( or basil)
1. Cut off the bottom and top of each berry, ending up with about 1 1/4 cups of tops and bottoms. Slice the centers of the berries and set aside.
2. Process the tops and bottoms of the berries with the jam, in a small food processor, until pureed. Mix the sliced berry centers into the puree. Cover with plastic wrap, and refrigerate until ready to serve.
3. When ready to serve, coarsely crush the cookies in a plastic zip type bag. Divide the crumbs among four glass bowls or goblets. Spoon about 1/2 of the berry mixture over the crumbs in each bowl/goblet. Stir the creme fraiche well and spoon about 1/3 cup of it (in total) on top of the berries. Then add the remaining berry mixture to each bowl/goblet. Garnish with a dollop of the remaining creme fraiche and a sprig of fresh mint.
|
__label__pos
| 0.933566 |
Hi, I have a 2002 tdci focus, if it's left for over 4 hours or over night it starts easily but but stops after about 15 seconds then takes about 30 seconds turning over to start again, after this it will start first time every time as long as it's not left for over 4 hours, can anyone help please?
|
__label__pos
| 0.784939 |
Definition of:silicon compiler
silicon compiler
Software that translates the electronic design of a chip into the layout of the logic gates, including the actual masking from one transistor to another. The source of the compilation is either a high-level description or the netlist. See HDL, netlist and logic synthesis.
Requested resource not found
|
__label__pos
| 0.981753 |
Take the 2-minute tour ×
sleep 1
echo "tmux failed to start"
share|improve this question
add comment
1 Answer
You can use this pattern to solve your problem: http://superuser.com/questions/180148/how-do-you-get-screen-to-automatically-connect-to-the-current-ssh-agent-when-re
share|improve this answer
add comment
Your Answer
|
__label__pos
| 0.983013 |
RSS Feed
The Zebra's Stripes, A Personal No-Fly Zone
A Real Estate Deal That Spans The Earth
For sale: 160 acres of rolling hills in California perfect for a vineyard, cattle ranch or communication with outer space. The Jamesburg Earth Station and its 10-story satellite dish once relayed broadcasts of historical events like the Apollo 11 moon landing. Now it's on the market.
Deconstructing Dengue: How Old Is That Mosquito?
Dengue fever, a nasty disease caused by a virus, is just beginning to show up in the U.S. It's carried from person to person by mosquitoes, and one researcher studying the spread is looking for clues in the age of the insects. But it's not very easy to tell how old a mosquito is.
As Gray Wolves Return, So Does Debate Over Hunting
Valentine's Day Special: Look Of Love
When you gaze into your sweetheart's eyes, look for enlarged pupils. Studies show that our pupils dilate when we feel strong emotions. Psychologist Bruno Laeng, of the University of Oslo, explains how scientists are using "pupillometry" and what pupil diameter suggests about mental activity.
The Science Of Yoga: The Risks And The Rewards
Drug Rapidly Counters Effects of Alzheimer's In Mice
Reporting in Science, researchers write that an FDA-approved drug for skin cancer had surprising results in mice with Alzheimer's. The drug rapidly cleared up amyloid protein from the brain and improved cognitive function. Co-author Gary Landreth discusses the drug's potential as a therapy for Alzheimer's.
Next Supercontinent Could Form At The North Pole
|
__label__pos
| 0.894495 |
Documentation Center
• Trial Software
• Product Updates
Friedman's test
p = friedman(X,reps)
p = friedman(X,reps,displayopt)
[p,table] = friedman(...)
[p,table,stats] = friedman(...)
p = friedman(X,reps) performs the nonparametric Friedman's test to compare column effects in a two-way layout. Friedman's test is similar to classical balanced two-way ANOVA, but it tests only for column effects after adjusting for possible row effects. It does not test for row effects or interaction effects. Friedman's test is appropriate when columns represent treatments that are under study, and rows represent nuisance effects (blocks) that need to be taken into account but are not of any interest.
The different columns of X represent changes in a factor A. The different rows represent changes in a blocking factor B. If there is more than one observation for each combination of factors, input reps indicates the number of replicates in each "cell," which must be constant.
The matrix below illustrates the format for a set-up where column factor A has three levels, row factor B has two levels, and there are two replicates (reps=2). The subscripts indicate row, column, and replicate, respectively.
Friedman's test assumes a model of the form
where μ is an overall location parameter, represents the column effect, represents the row effect, and represents the error. This test ranks the data within each level of B, and tests for a difference across levels of A. The p that friedman returns is the p value for the null hypothesis that . If the p value is near zero, this casts doubt on the null hypothesis. A sufficiently small p value suggests that at least one column-sample median is significantly different than the others; i.e., there is a main effect due to factor A. The choice of a critical p value to determine whether a result is "statistically significant" is left to the researcher. It is common to declare a result significant if the p value is less than 0.05 or 0.01.
friedman also displays a figure showing an ANOVA table, which divides the variability of the ranks into two or three parts:
• The variability due to the differences among the column effects
• The variability due to the interaction between rows and columns (if reps is greater than its default value of 1)
• The remaining variability not explained by any systematic source
The ANOVA table has six columns:
• The first shows the source of the variability.
• The second shows the Sum of Squares (SS) due to each source.
• The third shows the degrees of freedom (df) associated with each source.
• The fourth shows the Mean Squares (MS), which is the ratio SS/df.
• The fifth shows Friedman's chi-square statistic.
• The sixth shows the p value for the chi-square statistic.
p = friedman(X,reps,displayopt) enables the ANOVA table display when displayopt is 'on' (default) and suppresses the display when displayopt is 'off'.
[p,table] = friedman(...) returns the ANOVA table (including column and row labels) in cell array table. (You can copy a text version of the ANOVA table to the clipboard by selecting Copy Text from the Edit menu.
[p,table,stats] = friedman(...) returns a stats structure that you can use to perform a follow-up multiple comparison test. The friedman test evaluates the hypothesis that the column effects are all the same against the alternative that they are not all the same. Sometimes it is preferable to perform a test to determine which pairs of column effects are significantly different, and which are not. You can use the multcompare function to perform such tests by supplying the stats structure as input.
Friedman's test makes the following assumptions about the data in X:
• All data come from populations having the same continuous distribution, apart from possibly different locations due to column and row effects.
• All observations are mutually independent.
The classical two-way ANOVA replaces the first assumption with the stronger assumption that data come from normal distributions.
expand all
Test For Column Effects Using Friedman's Test
This example shows how to test for column effects in a two-way layout using Friedman's test.
Load the sample data.
load popcorn
popcorn =
5.5000 4.5000 3.5000
5.5000 4.5000 4.0000
6.0000 4.0000 3.0000
6.5000 5.0000 4.0000
7.0000 5.5000 5.0000
7.0000 5.0000 4.5000
This data comes from a study of popcorn brands and popper type (Hogg 1987). The columns of the matrix popcorn are brands (Gourmet, National, and Generic). The rows are popper type (Oil and Air). The study popped a batch of each brand three times with each popper. The values are the yield in cups of popped popcorn.
Use Friedman's test to determine whether the popcorn brand affects the yield of popcorn.
p = friedman(popcorn,3)
p =
The small value of p = 0.001 indicates the popcorn brand affects the yield of popcorn.
[1] Hogg, R. V., and J. Ledolter. Engineering Statistics. New York: MacMillan, 1987.
[2] Hollander, M., and D. A. Wolfe. Nonparametric Statistical Methods. Hoboken, NJ: John Wiley & Sons, Inc., 1999.
See Also
| |
Was this topic helpful?
|
__label__pos
| 0.942423 |
Subscribe English
look up any word, like fuck:
Cash; money; dinero. Derived from they keys on a keyboard that produce a dollar sign.
Yo, I got to get some Shift-4 son so I can get me a sweet Chrysler.
by Z-Train July 17, 2006
7 2
Money, Cash, moola, green paper. Any word that means money can define Shift 4. This word was created by using a computer keyboard. Hold down shift and press four and you make a money sign.
DJ DOC: Yo son, how we gonna get to Cali tomorrow for the show?
BV: Don't worry Doc, we be makin that Shift 4 so we will get there!
ex 2:
BV: U got my Shift 4?
Friend: How much I owe u?
BV: 300
by BV Productions March 22, 2009
5 3
|
__label__pos
| 0.878593 |
Navigation path
Lean EU_enterprise ar Twitter Facebook Ár gcainéal YouTube Ár bhfothaí RSS
Study on REACH contribution to development of emerging technologies
News in RSS
The purpose of this study is to assess current and forthcoming possibilities of REACH to effectively foster innovative development, enhanced commercialisation and speeded uptake of products of emerging technologies to ensure their contribution to addressing the challenges of the EU 2020. As spin-offs and SMEs are usual drivers behind the breakthrough of emerging technologies and make a significant input to the EU's competitiveness, a special attention will be given to the potential impacts of the current and suggested REACH provisions to their success and survival. The study will entail recommendations for areas in which improvement could be made.
Contract notice
Share: Facebook Google+ LinkedIn send this page to a friend
|
__label__pos
| 0.740786 |
Forgot your password?
+ - Silverlight on Linux
Submitted by puppydog
puppydog writes "Microsoft delivers its cross-platform plug-in and support for Linux. It appears that Microsoft is serious about making the Silverlight platform available everywhere. There are a number of interesting sub-plots in this development. 1. Microsoft acknowledges the importance of supporting Linux. 2. Microsoft openly supports the Mono initiative. 3. Microsoft can point to a positive side-effect of their Novell agreement. The story on eWeek"
Professional wrestling: ballet for the common man.
|
__label__pos
| 0.981876 |
lexicons and word studies
From: KULIKOVSKY, Andrew ([email protected])
Date: Wed Nov 06 1996 - 15:54:23 EST
>So what are the differences between the different word study tools? When
>I use each? What is the standard operating procedure if I want to know
>a word
>really means?
Well Jonathan there is no simple answer to this question.
In fact I don't think this really is the right question to ask.
I used to ask this question before I did some reading
into word semantics and linguistics in general, but now
I ask the question: "What meaning(s) can this word
communicate when it is used?"
When you ask "what does this word REALLY mean?"
it implies that a word only has ONE TRUE correct
central meaning - but that is just bolderdash.
If a person wishes to communicate a thought, that
thought must be meaningful if it is to be received
and understood by another. The thought has meaning
and when the speaker or writer wishes to communicate
a meaning he selects words which he believes will
best communicate that meaning. There may be many
different words that could be used.
Also, another speaker may use the same words but
be communicating an entirely different thought.
I believe this concept is the basic idea behind Louw
and Nida's lexicon.
So the question we need to ask is "What meaning
does this word communicate IN THIS CONTEXT?"
Generally a word will only communicate ONE
meaning in any given context, unless it is used
in a deliberately ambiguous way to be a play-
Keep in mind that context is the best indicator of a
words meaning and also that the meaning that one
writer attaches to a word may be quite different to
the meaning another writer attaches to the same
word or the way we understand that word.
Basically look at how the word is used with respect
to its context - especially how it is used by a
particular author.
For further reading see Ch 1 of DA Carson's Exegetical
Fallacies, "Linguistics for Students of NT Greek" by
David Alan Black is brilliant and so are "Semantics of
NT Greek" by JP Louw and "Biblical Words and their
Meaning" by Moises Silva. Also "Style and Discourse"
by Louw, Nida, Cronje and Snyman is very helpful.
| Andrew S. Kulikovsky B.App.Sc(Hons) MACS
| Software Engineer
| British Aerospace Australia
| Technology Park, Adelaide
| ph: +618 8290 8268
| fax: +618 8290 8800
| email: [email protected]
| What's the point of gaining everything this world has
| ...Look to Jesus Christ
|
__label__pos
| 0.738318 |
Known in the states as another fast, catchy Fat Wreck Chords band, Germany-based Wizo is a much deeper pond of water. Highly political in both their message and actions, Wizo deliver scathing, shocking political/social critiques through tight, catchy Punk songs and media-grabbing stunts.
Similar Artists
Listen to Wizo
and millions of other songs with Rhapsody
You're just minutes away from millions of songs.
Sign up now.
|
__label__pos
| 0.970174 |
Subscribe English
look up any word, like tittybong:
A fictional 11 year old British boy who discovered his homosexuality at a young age and went to ballet school.
He is depicted in the film "Billy Elliot," which was adapted into a Broadway musical by Elton John, of course.
Guy 1: Hey man, let's go watch Billy Elliot the Musical.
Guy 2: Oh, hey, yeah, then afterwards we can go drive off a cliff!
by Edison Heimbach April 12, 2011
3 30
|
__label__pos
| 0.836481 |
Shared publicly -
New method of bacterial cell engineering can produce better, cheaper drug therapies
Therapeutic proteins, which provide cutting-edge treatments of cancer, diabetes and countless other diseases, are among today's most widely consumed biopharmaceuticals. By introducing bottom-up carbohydrate engineering into common bacterial cells, Cornell researchers have discovered a way to make these drugs cheaper and safer.
A research team led by Matthew DeLisa, associate professor of chemical and biomolecular engineering, has invented a novel method for engineering human therapeutic glycoproteins simply and quickly using E. coli bacteria as a platform. Their work is detailed online March 25 in Nature Chemical Biology.
read more:
Gerd Moe-Behrens's profile photo
Add a comment...
|
__label__pos
| 0.942815 |
Exit Print View
Sun OpenDS Standard Edition 2.0 Administration Guide
Get PDF Book Print View
Document Information
Configuring the Directory Server
Configuring Security in the Directory Server
Managing Directory Data
Controlling Access To Data
Replicating Data
Managing Users and Groups
Directory Server Monitoring
Improving Performance
Advanced Administration
Running the Directory Server as a Non-Root User
Working With Directory Schema
Directory Schema Overview
Configuring Schema Checking
Working With Object Identifiers (OIDs)
Extending the Directory Schema
Managing Attribute Types
To View Attribute Types
To Create an Attribute Type
To Delete an Attribute Type
Managing Object Classes
To View Object Classes
To Create an Object Class
To Delete an Object Class
Extending the Schema With a Custom Schema File
Replicating Directory Schema
Managing the Schema With the Control Panel
To Display Schema Items
To Add a New Object Class
To Add a New Attribute to the Schema
Working With Object Identifiers (OIDs)
An object identifier (OID) is a numeric string used to uniquely identify an object in a directory. OIDs are used in directory schema, controls, and extended operations that require unique identification of elements.
LDAP object classes and attributes require a base object identifier (OID) that must be unique within your organization to avoid naming conflicts in the directory. If you plan to use your directory internally within your organization, use the OIDs provided in the directory server. If you plan to export your schema or publicly expose your schema in any way, you should consider entering a request for a unique OID for your organization. For more information, see Obtaining a Base OID.
After you have obtained a base OID, you can add branches to it for your organization's object classes and attributes. For example, the directory server uses an assigned base OID of For each component type, the directory server provides unique branch numbers to the base OID for each schema component.
Note - The directory server provides a comprehensive set of OIDs that should be sufficient for most applications. You can also request OIDs for addition to the directory server repository.
The following table shows the base OIDs used for each schema component:
Table 6
Base OIDs Used for Each Schema Component
OID Value
Object classes
Attribute syntaxes
Matching rules
Extended operations
General use
Experimental use
For each schema type, a unique branch number is added to the base OID. For example, attribute types use a branch number of 1 to form the OID of*1*. For each specific attribute type, the directory server assigns another set of branch numbers, one for each attribute type.
The following table displays a (partial) list of assigned OID values for attribute types.
Table 7
Assigned OID Values for Attribute Types
OID Value
Attribute Type
Note - The directory server allows the use of non-numeric OIDs as long as a corresponding numeric OID is defined within the schema. For example, you can use a non-numeric OID, mytestattribute-oid for the named attribute, myTestAttribute. The non-numeric OID must be all lowercase with the -oid appended to the named attribute. The use of non-numeric OIDs is an LDAP-specification violation but is permissible for ease of use.
Obtaining a Base OID
If you plan to make your directory server publicly available, or if you plan to redistribute your schema definitions for custom applications, you can obtain a base OID for your organization. You can use your own OIDs in a custom schema file if you plan to create custom extensions to the directory server. Alternatively, you can modify the schema configuration files by adding your base OID with its respective branch number.
Note - Do not modify the default OIDs unless you are sure of what you are doing. Modifying the OIDs can potentially damage your directory server.
To obtain and create base OIDs for your organization, perform the following steps:
1. Point your browser to the Internet Assigned Numbers Authority (IANA) web site at or a national organization in your country that handles such tasks. In some countries, corporations already have OIDs assigned to them. If your organization does not already have an OID, you can fill out a request at the IANA web site.
2. Determine the unique object classes, attributes, names, and other schema elements. Ensure that the names are descriptive to make it easier to manage the schema. One trick is to add a custom prefix to your custom object classes and attributes. For example, if your organization is Example.com, you can add the prefix Example before each custom schema element, such as adding Example to a Person object class as in ExamplePerson.
3. Create an OID registry to keep track of OID assignments. The registry is nothing more than a list that you maintain to ensure that OIDs and their descriptions are unique within your directory. The registry should be sufficiently protected so that only a privileged administrator can modify the registry.
4. Create branches in the OID tree to accommodate the schema elements.
5. Shut down the directory servers in your topology.
6. Manually edit the schema configuration files on each directory server in your topology. Replace each OID with your company's OID. This avoids problems with schema replication seeing differences in the schema and attempting to synchronize the information.
7. Manually edit any custom schema extensions. Ideally, you should define any custom extensions in a separate file.
|
__label__pos
| 0.981948 |
From Wikipedia, the free encyclopedia
Jump to: navigation, search
Location of Meetjesland in East Flanders.
The Meetjesland is a historical region in the north-west of the province East Flanders in Belgium.
There are many legends surrounding the origin of the name. The most known is the one of Emperor Charles V (Charles V) who was known for his sexual appetite. The story goes that when he traveled through the region people hid their daughters and their attractive young women, making emperor Charles think this region was full of old women (meetjes).
Due to its historical nature, "Meetjesland" is not a fixed region as such. Even so, it is widely accepted to comprise the following municipalities:
Eeklo is considered to be the capital of "Meetjesland".
The official holiday of "Meetjesland" is celebrated on June 21.
External links[edit]
Coordinates: 51°10′N 3°30′E / 51.167°N 3.500°E / 51.167; 3.500
|
__label__pos
| 0.733931 |
Fifa overrule AFC decision
FIFA overrules suspensions on five Asian countries
April 24, 2009
Soccer's world governing body has overruled a decision by the Asian Football Confederation (AFC) to suspend five countries, allowing them to vote in an upcoming election which could decide who runs the Asian game.
"Since we could not find a legal base within the AFC statutes, we believe that the (AFC legal ad hoc) committee has no power to pass any binding decisions," FIFA's legal director Marco Villiger said.
Laos, East Timor, Afghanistan and Mongolia were told by the AFC they could not vote because they had not participated in at least three AFC competitions in the last two years.
Kuwait were initially denied because the AFC ruled it would not recognise its federation's temporary administration.
Critics of AFC president Mohamed Bin Hammam say he sought the suspensions because the five countries refused to support his re-election campaign for a FIFA executive committee seat.
The Qatari goes up against Bahraini Salman bin Ebrahim al-Khalifa in the May 8 polls.
Bin Hammam has vowed to step down as AFC boss if defeated, but Al-Khalifa insists he does not want his job.
|
__label__pos
| 0.771437 |
Where Is the Sahel Located?
Sahel is the biogeographic zone of transition located between the Sahara desert in the North and the Sudanian Savannas in the south. It moves across the north of the African continent connecting the Atlantic Ocean and the Red Sea.
1 Additional Answer
The Sahel is also known as the Sahel belt which is located in Africa. It starts at the Atlantic ocean and ends at what is known as the African Horn. It contains such counties as Djibouti, Somalia, Ethiopia and Eritrea.
Q&A Related to "Where Is the Sahel Located"
The Sahel is located in Africa to the south of Tunisia. This location was essential to the early Ghana empire due to being convenient for shipping goods across the Sahara Desert
the sahel desert is located just southern part to the sahara desert and im pretty sure about that or you could say below the sahara desert. :D.
Mellott's Butcher Shop, 7826 Charlestown Rd Mercersburg, PA 17236. Ph
The Sahel of what my friend? Sahel means shore in arabic.
Explore this Topic
The location that runs from 2,400 miles from the Atlantic Ocean in the west and the Red Sea in the east is called the Sahel. This area is located in the northern ...
|
__label__pos
| 0.998949 |
Definitions for ELECTɪˈlɛkt
This page provides all possible meanings and translations of the word ELECT
Random House Webster's College Dictionary
1. to choose or select by vote, as for an office:
to elect a mayor.
Category: Government
2. to determine in favor of (a method, course of action, etc.).
3. to choose (a course of study).
4. (of God) to select for divine mercy or favor, esp. for salvation.
Category: Religion
5. (v.i.)to choose or select someone or something, as by voting.
Category: Government
6. (adj.)selected for an office, but not yet inducted (usu. used in combination):
the governor-elect.
Category: Government
7. select or choice:
an elect circle of artists.
8. chosen by God, esp. for eternal life.
Category: Religion
9. (n.)the elect or elected, persons chosen or worthy to be chosen. a person or persons chosen by God, esp. for favor or salvation.
Category: Common Vocabulary, Religion
Origin of elect:
1250–1300; ME < L ēlēctus, ptp. of ēligere to select, pick out =ē-e - +-ligere, comb. form of legere to gather
e•lec•teeɪ lɛkˈti(n.)
Princeton's WordNet
1. chosen, elect(adj)
an exclusive group of people
"one of the elect who have power inside the government"
2. elect, elite(adj)
selected as the best
"an elect circle of artists"; "elite colleges"
3. elect(ip)(verb)
elected but not yet installed in office
"the president elect"
4. elect(verb)
select by a vote for an office or membership
"We elected him chairman of the board"
5. elect(verb)
"I elected to have my funds deposited automatically"
Kernerman English Learner's Dictionary
1. elect(verb)ɪˈlɛkt
to vote sb into an official position
to elect a president; They elected her as their union representative.
2. electɪˈlɛkt
to choose to
She elected to put all her money in the fund.
1. elect(Noun)
In Calvinist theology, those foreordained to Heaven.
2. elect(Verb)
To choose or make a decision (to do something)
3. elect(Verb)
To choose (a candidate) in an election
4. elect(Adjective)
He is the President-elect.
Webster Dictionary
1. Elect(adj)
chosen; taken by preference from among two or more
2. Elect(adj)
3. Elect(adj)
4. Elect(noun)
one chosen or set apart
5. Elect(noun)
those who are chosen for salvation
6. Elect(verb)
to pick out; to select; to choose
7. Elect(verb)
8. Elect(verb)
British National Corpus
1. Verbs Frequency
Translations for ELECT
Kernerman English Multilingual Dictionary
to choose by vote
He was elected chairman; elected to the committee.
Get even more translations for ELECT »
Find a translation for the ELECT definition in other languages:
Select another language:
Discuss these ELECT definitions with the community:
Use the citation below to add this definition to your bibliography:
"ELECT." STANDS4 LLC, 2014. Web. 15 Mar. 2014. <>.
Are we missing a good definition for ELECT?
The Web's Largest Resource for
Definitions & Translations
A Member Of The STANDS4 Network
Nearby & related entries:
Alternative searches for ELECT:
|
__label__pos
| 0.952037 |
GrassBase - The Online World Grass Flora
HABIT Perennial. Rhizomes short; pachymorph. Culms scandent; 500–1000–1500 cm long; woody. Culm-internodes terete. Culm-nodes flush with internodes (1/1). Lateral branches dendroid. Branch complement many; in a clump; with 1 branch dominant; thinner than stem. Culm-sheaths persistent (1/1); without auricles (1/1). Culm-sheath blade linear (1/1). Ligule an eciliate membrane (1), or absent (1). Leaf-blade base with a brief petiole-like connection to sheath. Leaf-blades deciduous at the ligule; lanceolate.
INFLORESCENCE Synflorescence bractiferous; scanty; with spathaceous subtending bracts; with axillary buds at base of spikelet.
Fertile spikelets sessile.
FERTILE SPIKELETS Spikelets comprising 1 fertile florets; with a barren rhachilla extension, or with diminished florets at the apex. Spikelets lanceolate; subterete; 14–25.25–40.8 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes brief up to lowest fertile floret (1), or elongated below proximal fertile floret. Rhachilla elongation stout (1), or slender (1).
GLUMES Glumes two, or several (1); persistent; shorter than spikelet (1), or reaching apex of florets (1). Lower glume lanceolate (1), or ovate (1); 0.7–0.75–0.8 length of upper glume; chartaceous; without keels; 13 -veined (1/1). Lower glume surface without pits. Lower glume apex obtuse (1), or acute. Upper glume lanceolate (1), or elliptic (1); 1.1 length of adjacent fertile lemma; chartaceous; without keels; 19 -veined (1/1). Upper glume apex obtuse (1), or acute (1), or acuminate (1).
FLORETS Fertile lemma lanceolate; chartaceous; without keel; wingless; 7 -veined (1/1). Lemma surface smooth (1), or granulose (1); unwrinkled; without grooves. Lemma apex acute. Palea 1 length of lemma; chartaceous; 6 -veined (1/1). Palea keels approximate. Apical sterile florets 0 in number (1), or 1 in number; barren; linear.
FLOWER Lodicules 3; glabrous (1), or ciliate (1). Anthers 6. Stigmas 2. Ovary umbonate; pubescent on apex (1/1).
FRUIT Caryopsis with adherent pericarp.
|
__label__pos
| 0.815808 |
All year, NPR is exploring how people are changing the Earth's climate and how the climate is changing us. It's called Climate Connections with National Geographic.
Today, we'll visit some geographic jewels - the Sky Islands of southern Arizona and northern Mexico. As temperatures rise, these mountaintop refuges are starting to look more like the desert below.
NPR's Ted Robbins explains.
TED ROBBINS: Look at a topographic map of North America. You'll see two huge spines in the West - the Rocky Mountain stretching from Canada to the desert southwest, and south of there, in Mexico, the Sierra Madre.
In between are relatively small, isolated mountain ranges rising from the desert, much as islands rise from the ocean. Which is why the ranges - with names like the Huachucas, the Chiricahuas, the Catalinas - are called Sky Island. And they are home to unparalleled diversity.
Mr. MATT SKROCH (Sky Island Alliance): Believe it or not, there's more mammals that occur here in southeastern Arizona than anywhere else in the United States.
ROBBINS: Matt Skroch is head of the Sky Island Alliance, an environmental group trying to protect this intersection between tropical species on the northern end of their range...
Mr. SKROCH: Such as jaguars, ocelots, greyhawks, Mexican possums.
ROBBINS: And temperate species on the southern end of their range like black bear and northern goshawk - not to mention 20 species of hummingbird. But much the way oceans are rising and claiming some seaside habitat, hotter, drier conditions are moving up the slopes of the Sky Islands.
Matt Skroch and I drive from the heat of Tucson to the top of the Santa Catalina Mountains. In less than an hour, we can climb 7,000 feet, the ecological equivalent of going from the desert southwest to Canada. We passed giant saguaro cactus, then oak woodlands, then about halfway up the mountain, we see the first sign of a cooler climate - a ponderosa pine in a small canyon.
(Soundbite of car door closing)
ROBBINS: It's the perfect place to see change.
Mr. SKROCH: Because we're at the fringe of where the pine occurs within the Sky Islands, you also notice, looking across this canyon, that about 80 percent of the pines are dead. And that's because it's getting hotter.
ROBBINS: This is gradual change, creeping up the mountainside like a rising tide. Farther up the mountain, we see the equivalent of a tsunami.
Mr. SKROCH: Now, down there, you don't see any tree that's alive.
ROBBINS: This hillside burned in two swift hot fires in the last five years -the Bullock fire and the Aspen fire. More than 100,000 acres burned in the Catalina range. Very few pine, spruce, or fir are growing back here. Instead, warmer-adapted species like oaks and grasses are starting to come in.
Carol Mack owns the Mt. Lemmon General Store in Summer Haven, a village near the top of the Catalinas. She says she's starting to see animals she's never seen here.
Ms. CAROL MACK (Owner, Mt. Lemmon General Store): We've seen a road runner up here. Now, how far out of their element could a road runner be?
(Soundbite of "Road Runner")
ROBBINS: Hey, even if you've only seen them in Warner Brothers cartoons, you know the road runner belongs in the desert. But they appear to be climbing the mountain to some rates. Carol Mack's first Mt. Lemmon General store burned in the Aspen fire along with nearly 350 other buildings.
Now, above the new store in town, there's little forest covered.
Ms. MACK: I hear from so many people who have rebuilt that the winds are just so bad now. And the sun is just so much more intense. It just feels hotter to us.
ROBBINS: It feels hotter, and it is drier. The southwest is in the middle of a six-year drought. But drought is a natural occurrence.
(Soundbite of chainsaw)
Back in Tucson, scientists at the University of Arizona Tree-Ring labs slice and polish cross-sections of ancient trees to study climate change.
Lab director Tom Swetnam shows me a sample from the Chiricahua Mountains. It has a band of thinner rings, indicating a drought that lasted not six years, but six decades.
Dr. THOMAS SWETNAM (Director, Laboratory of Tree-Ring Research, University of Arizona): And so a sixty-year long drought in the Colorado River basin would exceed anything that we've seen in the modern period, so far, so far.
ROBBINS: Swetnam says that because scientists are beginning to think that the combination of normal drought with human-caused higher temperatures might tip the region into a mega-drought.
Dr. SWETNAM: The effects of global warming might be a trigger to those sorts of extended drought periods.
ROBBINS: As the Sky Island shrink, people are working on ways to protect what's left. More prescribed burns and tree thinning to prevent cataclysmic fires. More than protection for animals that migrate between the Sky Islands, and ultimately, ways to save species at the very top stranded with no place to go.
Ted Robbins, NPR News, Tucson.
SIMON: You can see the latest episode of our animated series, "It's All About Carbon," from NPR's Robert Krulwich and public television's "Wild Chronicles" at our Web site,
Support comes from:
|
__label__pos
| 0.826877 |
Is Salt and Water a Mixture?
Salt and water is a mixture. Salt and water make a homogeneous mixture called a solution.
Q&A Related to "Is Salt and Water a Mixture?"
salt dissolves in H2o. to be considered a mixture, something must mix. That means, either something, dissolves into the other contents, or they show each others properties. If you
1. Turn on a stove element to its highest setting. 2. Pour 1 cup of saltwater into a pot and place the lid on the pot. Place the pot onto the stove. 3. Check the water frequently
If you want to match the salinity of seawater, add 35 grams of salt to every
Salt water is salty because there is actually salt dissolved in the water. The amount of salt in the water is referred to as the salinity of the water.
Explore this Topic
With the Evaporation test, we can prove that salt water is a mixture, not a compound. Make about 10ml of salt water and heat it till water evaporates. You will ...
Yes, it is possible to separate a mixture of salt, water and sand. When salt and sand are mixed it seems impossible to separate the two, but you add water and ...
When salt water mixes with fresh water the resulting aquatic system is known as a brackish system. The mix is typically has more saline than fresh water. ...
|
__label__pos
| 0.996072 |
Enamel pearl
From Wikipedia, the free encyclopedia
Jump to: navigation, search
Enamel pearl
Classification and external resources
ICD-10 K00.2
ICD-9 520.2
An enamel pearl is a condition of teeth where enamel is found on locations where enamel is not supposed to be, such as on a root surface. They are found usually in the area between roots, which is called a furcation, of molars. Enamel pearls are not common in teeth with a single root. The most common location of enamel pearl is the furcation areas of the maxillary and mandibular third molar roots. The Enamel pearls are formed essentially from the Hertwig's Epithelial root sheath. After the initiation of the formation of dentin in the root area of the tooth, the root sheath disintegrates and moves away from the root surface so that the cells of the dental sac can come in contact of predentin to differentiate into cementoblasts and start deposition of cementum. However, if the cells of epithelial root sheath remain adherent to predentin, they may differentiate into fully functional ameloblasts and deposit Enamel. Such droplets of enamel are called Enamel Pearls.
• Steinbacher D.M., Sierakowski S.R., First Aid for the NBDE Part 1 2nd Ed. p.625, McGraw Hill, 2011
|
__label__pos
| 0.729466 |
Forgot your password?
Related Topics
Life of Pi Test | Final Test - Hard
Purchase our Life of Pi Lesson Plans
Final Test - Hard
Name: _____________________________ Period: ___________________________
Short Answer Questions
1. Since Pi had no bait, what did he cut up to fish with in the morning, after his leather shoe was unsuccessful?
2. What was Pi careful to maintain with the tiger in his quest to be known by the tiger as the alpha male?
3. What did Pi fail to control as time passed on the liferaft?
4. What did Pi tell to the interviewers?
5. What did the officials say to the author about the interview with Pi?
Essay Topics
In the early chapters, there are different descriptions of animal behavior. Choose one, and compare and contrast it to a later animal behavior or event in the book that has the same characteristics.
Which animals in the book are most like people in Pi's life? Use specific examples to explain why you chose various animals and what similar characteristics to their human counterparts they exhibit.
Using examples from the book, which one of the animals in the zoo is most like Pi and why?
(see the answer keys)
This section contains 233 words
(approx. 1 page at 300 words per page)
Purchase our Life of Pi Lesson Plans
Follow Us on Facebook
|
__label__pos
| 0.99839 |
The Impossible State: North Korea, Past and Future (Hardback)
by Victor Cha
Format: Hardback 544 pages
Not in stock
Usually despatched in 3-5 days
Price check
RRP £25.00
You save: £6.20
Delivered FREE
in the UK
Much discussed and often maligned, precious little is known or understood about North Korea, the world's most controversial and isolated country. In "The Impossible State" Victor Cha pulls back the curtain, providing an unprecedented insight into North Korea's history, the rise of the Kim family dynasty, and the obsessive personality cult that surrounds them. He illuminates the repressive regime's complex economy and culture, its appalling record of human-rights abuses, its belligerent relationship with its neighbours and the United States, and analyzes the regime's major security issues - from the seemingly endless war with its southern counterpart to its terrifying nuclear ambitions - all in the light of the destabilizing effects of Kim Jong-il's recent death. How has this enigmatic nation-state continued to survive when it regularly violates its own citizens' inalienable rights and has suffered severe famine, global economic sanctions, a collapsed economy, and near-total isolation from the rest of the world? Cha reveals a land facing a pivotal and disquieting transition of power from tyrannical father to inexperienced son, and delves into the ideology that leads an oppressed, starving populace to cling so fiercely to its failed leadership. With rare personal anecdotes from the author's time in Pyongyang and his tenure as a White House adviser, this engagingly written, authoritative, and highly accessible account offers much-needed answers to the most pressing questions about North Korea and ultimately warns of a regime that might be closer to its end than many might think - a political collapse for which the Western world may be woefully unprepared.
Book details
The Bodley Head Ltd
Other books by this author See all titles
Customers who bought this title, also bought...
This book can be found in...
|
__label__pos
| 0.929313 |
After taking its first steps in 2001, Yoki has grown into a brand known for innovative, sensational styles that sync up with the latest trends. Their unique designs can be seen across the United States, Canada, South America and Europe. Featuring classic, modern apparel, accessories and footwear, Yoki's collections are tailored to the hippest fashions.
add to my favorites
today's events
|
__label__pos
| 0.754083 |
My Account: Log In | Join | Renew
1st Page
This article in SSSAJ
1. Vol. 71 No. 1, p. 75-85
Received: Feb 9, 2006
Published: Jan, 2007
* Corresponding author(s):
Biological Activity of Humic Substances Is Related to Their Chemical Structure
1. Adele Muscolo *,
2. Maria Sidari,
3. Emilio Attinà,
4. Ornella Francioso,
5. Vitaliano Tugnoli and
6. Serenella Nardi
1. D ipartimento di Gestione dei Sistemi Agrari, e Forestali, Università degli Studi Mediterranea, Feo di Vito, 89060 Reggio Calabria, Italy
D ipartimento di Scienze e Tecnologie, Agroambientali, Università di Bologna, Via Fanin 40, 40127 Bologna, Italy
D ipartimento di Biochimica, Università di Bologna, Via Belmeloro 8/2, 40126 Bologna, Italy
D ipartimento di Biotecnologie Agrarie, Facoltà di Agraria, Agripolis, Strada Romea 16–35020, Legnaro, Padova, Italy
To understand if the biological activity of humic substances may be related to their molecular weight or chemical structure, two humic substances, derived from an Ah horizon of uncultivated couch grass [Elytrigia repens (L.) Desv. ex Nevski] and an Ah horizon of forest soil, were extensively characterized by means of different spectroscopic techniques (diffuse reflectance infrared Fourier transform [DRIFT] and 1H nuclear magnetic resonance [NMR]). The two humic substances, each separated in fractions with low (<3500 Da) and high (>3500 Da) relative molecular mass were compared for their effects on Pinus nigra J.F. Arnold callus. Growth of callus, the soluble sugar content, free amino acid pool, and the activities of the key enzymes involved in C and N metabolism were investigated. Callus was grown for a subculture period (28 d) on basal Murashige and Skoog medium plus humic matters with or without different hormones: indole-3-acetic acid, 2,4-dichlorophenoxyacetic acid, or 6-benzylaminopurine. The results of 1H-NMR spectra and the DRIFT spectroscopy showed significant differences in the chemical composition between forest and grass humic substances. A large amount of aliphatic and H-sugarlike component and an intense chemical shift of the β-CH3 region in both grass humic fractions were observed, while high contents of betaine, organic acid, and COOH groups in both forest humic fractions were detected. A different biological activity between the grass and forest humic fractions was also observed. Thus, the different activity of the two humic substances used seems related to the diverse chemical composition rather than to different molecular weights.
Copyright © 2007Soil Science Society of America
Facebook Twitter
|
__label__pos
| 0.764548 |
Horn antennas, colloquially referred to as gain horn antennas, are used for the transmission and reception of microwave signals. This name is derived from their characteristic flared appearance. The flared portion can be square, rectangular, or conical in shape. The maximum radiation and response corresponds with the axis of the horn. In this respect, the antenna resembles an acoustic horn. Horn antennas are usually fed by waveguides in microwave antenna, high gain antenna and high gain wireless antenna, and microwave antenna applications.
The main operating specifications for horn antennas are operating frequency range and gain. The operating frequency is the frequency range through which the horn antenna will meet all functional specifications. Gain is the ratio of the power required at the input of a loss-free reference antenna to the power supplied to the input of the given antenna to produce, in a given direction, the same field strength at the same distance usually in the direction of maximum radiation. Antenna gain is normally expressed in decibels or dB.
In order to function properly, horn antennas must be a certain minimum size relative to the wavelength of the incoming or outgoing electromagnetic field. If the horn is too small or the wavelength is too large (the frequency is too low), the antenna will not function efficiently. Horn antennas are commonly used as the active element in a dish antenna. The horn is pointed toward the center of the dish reflector. The use of a horn, rather than a dipole antenna or any other type of antenna, at the focal point of the dish minimizes loss of energy (leakage) around the edges of the dish reflector. They also minimize the response of the antenna to unwanted signals not in the favored direction of the dish. Horn antennas can be used without attendant components in short range radar systems, particularly those used by law-enforcement personnel to measure the speeds of approaching or retreating vehicles.
Related Products & Services
• RF Waveguide Assemblies
• RF Waveguide Components
• RF Waveguide Couplers
• RF Waveguide Phase Shifters
|
__label__pos
| 0.819773 |
Information Services banner Edinburgh Research Archive The University of Edinburgh crest
Edinburgh Research Archive >
Philosophy, Psychology and Language Sciences, School of >
Psychology >
Psychology Undergraduate thesis collection >
Please use this identifier to cite or link to this item:
Files in This Item:
File Description SizeFormat
Stewart dissertation.pdfonly available to kBAdobe PDF
Title: Does implicit causality influence children's sentence comprehension
Authors: Stewart, Gillian
Supervisor(s): Donaldson, Morag
Issue Date: 2006
Abstract: Studies investigating adults’ sentence comprehension have found that certain verbs convey implicit information about the causality of the sentence. The present study tested children aged 8; 10 – 11;7 years (M = 10;3) to investigate if children also use implicit causality of verbs to comprehend sentences. Firstly, a sentence completion task was carried out by each child. Half the sentences included NP1 verbs, for example, Bart phoned Marge because…. The first clause of these sentences imply that the cause of the event is due to the subject noun phrase (NP1); in this case, Bart. The other half of the sentences included NP2 verbs; sentences such as Kenny liked Bebe because… were used. NP2 verbs assign the cause of the event to the object noun phrase (NP2). Secondly, the children were tested on an answer task. Again, half of the sentences included NP1 verbs, the other half included NP2 verbs. Sentences were completed with either congruent or incongruent sentence endings. In congruent sentences, such as Bart amused Homer because he told funny jokes, the verb in the first clause and the sentence ending both imply the same character has caused the event. Incongruent sentences, such as Marge punished Lisa because she was in a bad mood, include sentence endings which imply the character who had caused the event to be different to the character implied by the verb. The children were asked which character, in the congruent and incongruent sentences, was referred to as the pronoun (he/she) later in the sentence. The majority of children added a congruent sentence ending in the completion task. In the answer task the children responded with a greater number of correct answers when a congruent sentence ending was used. Therefore, children, in the same way as adults, use the verb to imply information about the causality of a sentence. In conclusion, the implicit causality of verbs does influence children’s sentence comprehension.
Keywords: implicit causality
sentence comprehension
causality of sentences
implicit causality of verbs
congruent sentences
incongruent sentences
Appears in Collections:Psychology Undergraduate thesis collection
|
__label__pos
| 0.99998 |
wjz-13 1057-the-fan 1300logo2_67x35
Tropical Storm Andrea
rain generic
Hundreds Of Outages As Andrea Brings Heavy Rain
Hundreds of customers are without power and motorists are facing a messy morning commute as Tropical Storm Andrea brings heavy rains to the mid-Atlantic region.
Wind, Heavy Rain To Halt 2-Way Traffic On Westbound Bay Bridge
Maryland Transportation Authority officials say winds and heavy rain will likely prevent two-way traffic on one Bay Bridge’s span.
First Tropical Storm Of The Season, Andrea, Forms
The first named storm of Atlantic season, Andrea, has formed over the Gulf of Mexico and was likely to bring wet weather to parts of Florida’s west coast by the end of the week.
|
__label__pos
| 0.900702 |
Best matches, sorted by the Matches.
1-20 of 20 possibilities
orbit of moon or satellite farthest from earth, point of apogee
satellite equipped with a telescope to observe infrared radiation astronomy satellite
craft capable of traveling in outer space; technically, a satellite around the sun ballistic capsule , spacecraft , space vehicle
acceleration toward the center that holds a satellite in elliptical orbit centripetal acceleration
artificial satellite that relays signals back to earth; moves in a geostationary orbit communications satellite
parachute of spacecraft or satellite drogue parachute
satellite that rotates with Earth geostationary orbit satellite , geosynchronous orbit satellite
terrorist group formed in 1977 as the result of a split with the Popular Front for the Liberation of Palestine; became a satellite of al-Fatah; made terrorist attacks on Israel across the Lebanese border Jabat al-Tahrir al-Filistiniyyah , Palestine Liberation Front , PLF
(astronomy) a real or apparent slow oscillation of a moon or satellite libration
arithmetic mean of the maximum and minimum distances of a celestial body (satellite or secondary star) from its primary mean distance
satellite that transmits frequent picture of the earth below meteorological satellite , weather satellite
any natural satellite of a planet moon
natural satellite of the Earth Moon
planetary satellite moon
earth satellite moon
earth's satellite moon
path in space of a planet or satellite orbit
Search another word or see satellite on Thesaurus | Reference
Copyright © 2014, LLC. All rights reserved.
• Please Login or Sign Up to use the Recent Searches feature
|
__label__pos
| 0.837958 |
Ising model
From Wikipedia, the free encyclopedia
(Redirected from Ising Model)
Jump to: navigation, search
The Ising model (/ˈsɪŋ/; German: [ˈiːzɪŋ]), named after the physicist Ernst Ising, is a mathematical model of ferromagnetism in statistical mechanics. The model consists of discrete variables that represent magnetic dipole moments of atomic spins that can be in one of two states (+1 or −1). The spins are arranged in a graph, usually a lattice, allowing each spin to interact with its neighbors. The model allows the identification of phase transitions, as a simplified model of reality. The two-dimensional square-lattice Ising model is one of the simplest statistical models to show a phase transition.[1]
The Ising model was invented by the physicist Wilhelm Lenz (1920), who gave it as a problem to his student Ernst Ising. The one-dimensional Ising model has no phase transition and was solved by Ising (1925) himself in his 1924 thesis.[2] The two-dimensional square lattice Ising model is much harder, and was given an analytic description much later, by Lars Onsager (1944). It is usually solved by a transfer-matrix method, although there exist different approaches, more related to quantum field theory.
Consider a set of lattice sites Λ, each with a set of adjacent sites (e.g. a graph) forming a d-dimensional lattice. For each lattice site j ∈ Λ there is a discrete variable σj such that σj ∈ {+1, −1}. A spin configuration, σ = (σj)j∈Λ is an assignment of spin value to each lattice site.
For any two adjacent sites ij ∈ Λ one has an interaction Jij, and a site i ∈ Λ has an external magnetic field hi. The energy of a configuration σ is given by the Hamiltonian Function
H(\sigma) = - \sum_{<i~j>} J_{ij} \sigma_i \sigma_j -\mu \sum_{j} h_j\sigma_j
where the first sum is over pairs of adjacent spins (every pair is counted once). <ij> indicates that sites i and j are nearest neighbors. The magnetic moment is given by µ. Note that the sign in the second term of the Hamiltonian above should actually be positive because the electron's magnetic moment is antiparallel to its spin, but the negative term is used conventionally.[3] The configuration probability is given by the Boltzmann distribution with inverse temperature β ≥ 0:
P_\beta(\sigma) ={e^{-\beta H(\sigma)} \over Z_\beta},
where β = (kBT)−1
and the normalization constant
Z_\beta = \sum_\sigma e^{-\beta H(\sigma)}
is the partition function. For a function f of the spins ("observable"), one denotes by
\langle f \rangle_\beta = \sum_\sigma f(\sigma) P_\beta(\sigma) \,
the expectation (mean value) of f.
The configuration probabilities Pβ(σ) represent the probability of being in a state with configuration σ in equilibrium.
The minus sign on each term of the Hamiltonian function H(σ) is conventional. Using this sign convention, the Ising models can be classified according to the sign of the interaction: if, for all pairs i,j
Jij>0, the interaction is called ferromagnetic
Jij<0, the interaction is called antiferromagnetic
Jij=0, the spins are noninteracting
otherwise the system is called nonferromagnetic.
In a ferromagnetic Ising model, spins desire to be aligned: the configurations in which adjacent spins are of the same sign have higher probability. In an antiferromagnetic model, adjacent spins tend to have opposite signs.
The sign convention of H(σ) also explains how a spin site j interacts with the external field. Namely, the spin site wants to line up with the external field. If:
hj>0, the spin site j desires to line up in the positive direction
hj<0, the spin site j desires to line up in the negative direction
hj=0, there is no external influence on the spin site.
Ising models are often examined without an external field interacting with the lattice:
Another common simplification is to assume that all of the nearest neighbors <ij> have the same interaction strength. Then we can set Jij = J for all j in Λ such that:
H(\sigma) = -J\sum_{<i~j>}\sigma_i \sigma_j.
When the external field is everywhere zero, h = 0, the Ising model is symmetric under switching the value of the spin in all the lattice sites; a non zero field breaks this symmetry.
2. If a spin at any given position i is 1, what is the probability that the spin at position j is also 1?
Basic properties and history[edit]
Visualization of the translation-invariant probability measure of the one-dimensional Ising model.
The most studied case of the Ising model is the translation-invariant ferromagnetic zero-field model on a d-dimensional lattice, namely, Λ = Zd, Jij = 1, h = 0.
In his 1924 PhD thesis, Ising solved the model for the 1D case, which can be thought of as a linear horizontal lattice where each site only interacts with its left and right neighbor. In one dimension, the solution admits no phase transition.[4] Namely, for any positive β, the correlations <σiσj> decay exponentially in |ij|:
\langle \sigma_i \sigma_j \rangle_\beta \leq C \exp(-c(\beta) |i-j|),\,
and the system is disordered. On the basis of this result, he incorrectly concluded that this model does not exhibit phase behaviour in any dimension.
The Ising model undergoes a phase transition between an ordered and a disordered phase in 2 dimensions or more. Namely, the system is disordered for small β, whereas for large β the system exhibits ferromagnetic order:
\langle \sigma_i \sigma_j \rangle_\beta \geq c(\beta) > 0.\,
This was first proven by Rudolf Peierls in 1936,[5] using what is now called a Peierls argument.
The Ising model on a two-dimensional square lattice with no magnetic field was analytically solved by Lars Onsager (1944). Onsager showed that the correlation functions and free energy of the Ising model are determined by a noninteracting lattice fermion. Onsager announced the formula for the spontaneous magnetization for the 2-dimensional model in 1949 but did not give a derivation. Yang (1952) gave the first published proof of this formula, using a limit formula for Fredholm determinants, proved in 1951 by Szegő in direct response to Onsager's work.[6]
Historical significance[edit]
One of Democritus' arguments in support of atomism was that atoms naturally explain the sharp phase boundaries observed in materials, as when ice melts to water or water turns to steam. His idea was that small changes in atomic-scale properties would lead to big changes in the aggregate behavior. Others believed that matter is inherently continuous, not atomic, and that the large-scale properties of matter are not reducible to basic atomic properties.
No phase transitions in finite volume[edit]
1. The partition function is a sum of e−βE over all configurations.
2. the exponential function is everywhere analytic as a function β.
3. the sum of analytic things is analytic.
This argument works for a finite sum of exponentials, and correctly establishes that there are no singularities in the free energy of a system of a finite size. For systems which are in the thermodynamic limit (that is, for infinite systems) the infinite sum can lead to singularities. The convergence to the thermodynamic limit is fast, so that the phase behavior is apparent already on a relatively small lattice, even though the singularities are smoothed out by the system's finite size.
This was first established by Rudolf Peierls in the Ising model.
Peierls droplets[edit]
M= {1\over N} \sum_{i=1}^{N} S_i.
2. So for every configuration with magnetization M there is a configuration with magnetization −M with equal probability
3. So the magnetization is zero.
For very high temperatures, the magnetization is zero, as it is at infinite temperature. To see this, note that if spin A has only a small correlation ε with spin B, and B is only weakly correlated with C, but C is otherwise independent of A, the amount of correlation of A and C goes like ε2. For two spins separated by distance L, the amount of correlation goes as εL but if there is more than one path by which the correlations can travel, this amount is enhanced by the number of paths.
The number of paths of length L on a square lattice in d dimensions is
N(L) = (2d)^L
\sum_L (2d)^L (\varepsilon)^L
which goes to zero when ε is small.
The energy of a droplet of plus spins in a minus background is proportional to the perimeter of the droplet L, where plus spins and minus spins neighbor each other. For a droplet with perimeter L, the area is somewhere between (L − 2)/2 (the straight line) and (L/4)2 (the square box). The probability cost for introducing a droplet has the factor e−βL, but this contributes to the partition function multiplied by the total number of droplets with perimeter L, which is less than the total number of paths of length L:
N(L)< 4^{2L}.
\sum_L L^2 4^{-2L} e^{-4\beta L}
which goes to zero at large β. For β sufficiently large, this exponentially suppresses long loops, so that they cannot occur, and the magnetization never fluctuates too far from −1.
Kramers–Wannier duality[edit]
Kramers and Wannier were able to show that the high temperature expansion and the low temperature expansion of the model are equal up to an overall rescaling of the free energy. This allowed the phase transition point in the two-dimensional model to be determined exactly (under the assumption that there is a unique critical point).
Yang–Lee zeros[edit]
Monte Carlo Methods for Numerical Simulation[edit]
The Ising model can often be difficult to evaluate numerically if there are many states in the system. Consider an Ising Model with L lattice sites. Let:
• L = |Λ|: the total number of sites on the lattice,
• σj ∈ {−1, +1}: an individual spin site on the lattice, j = 1, ..., L,
• S ∈ {−1, +1}L: state of the system.
Since every spin site has ±1 spin, there are 2L different states that are possible.[7] This motivates the reason for the Ising Model to be simulated using Monte Carlo Methods.[7]
The Hamiltonian Function that is commonly used representing the energy of the model when using Monte Carlo Methods is:
H(\sigma) = - J\sum_{<ij>}\sigma_i \sigma_j -h\sum_{j}\sigma_j.
Furthermore, the Hamiltonian is further simplified by assuming zero external field (h) since many questions that are posed to be solved using the model can be answered in absence of an external field. This leads us to the following energy equation for state σ:
Two such examples of estimates of interest are the specific heat or the magnetization of the magnet at a given temperature.[7]
The Metropolis Algorithm[edit]
Overview of Algorithm[edit]
The Metropolis–Hastings algorithm is the most commonly used Monte Carlo algorithm to calculate Ising Model estimations.[7] The algorithm first chooses selection probabilities g(μ, ν), which represent the probability that state ν is selected by the algorithm out of all states, given that we are in state μ. It then uses acceptance probabilities A(μ, ν) so that detailed balance is satisfied. If the new state ν is accepted, then we move to that state and repeat with selecting a new state and deciding to accept it. If ν is not accepted then we stay in μ. This process is repeated until some stopping criteria is met, which for the Ising model is often when the lattice becomes ferromagnetic, meaning all of the sites point in the same direction.[7]
When implementing the algorithm, we must ensure that g(μ, ν) is selected such that ergodicity is met. In thermal equilibrium a system's energy only fluctuates within a small range.[7] This is the motivation behind the concept of single-spin-flip dynamics, which states that in each transition, we will only change one of the spin sites on the lattice.[7] Furthermore, by using single- spin-flip dynamics, we can get from any state to any other state by flipping each site that differs between the two states one at a time.
The maximum amount of change between the energy of the present state, Hμ and any possible new state's energy Hν (using single-spin-flip dynamics) is 2J between the spin we choose to "flip" to move to the new state and that spin's neighbor.[7] Thus, in a 1D-Ising Model, where each site has 2 neighbors (left, and right), the maximum difference in energy would be 4J.
Let c represent the lattice coordination number; the number of nearest neighbors that any lattice site has. We assume that all sites have the same number of neighbors due to periodic boundary conditions.[7]
Algorithm Specification[edit]
Specifically for the Ising model and using single-spin-flip dynamics, we can establish the following.
Since there are L total sites on the lattice, using single-spin-flip as the only way we transition to another state, we can see that there are a total of L new states ν from our present state μ. The algorithm assumes that the selection probabilities are equal to the L states: g(μ, ν) = 1/L. Detailed balance tells us that the following equation must hold:
\frac{P(\mu,\nu)}{P(\nu,\mu)} = \frac{g(\mu,\nu)A(\mu,\nu)}{g(\nu,\mu)A(\nu,\mu)} = \frac{A(\mu,\nu)}{A(\nu,\mu)} = \frac{P_\beta(\nu)}{P_\beta(\mu)} = \frac{\frac{1}{Z}e^{-\beta(H_\nu)}}{\frac{1}{Z}e^{-\beta(H_\mu)}} = e^{-\beta(H_\nu-H_\mu)}.
Thus, we want to select the acceptance probability for our algorithm to satisfy:
If Hν > Hμ then A(ν, μ) > A(μ, ν) Metropolis sets the larger of A(μ, ν) or A(ν, μ) to be 1. By this reasoning the acceptance algorithm is:[7]
e^{-\beta(H_\nu-H_\mu)}, & \text{if }H_\nu-H_\mu>0 \\
1, & \text{otherwise}.
The basic form of the algorithm is as follows:
1. Pick a spin site using selection probability g(μ, ν) and calculate the contribution to the energy involving this spin.
2. Flip the value of the spin and calculate the new contribution.
3. If the new energy is less, keep the flipped value.
4. If the new energy is more, only keep with probability e^{-\beta(H_\nu-H_\mu)}.
5. Repeat.
Viewing the Ising Model as a Markov Chain[edit]
It is easy to view the Ising Model as a Markov Chain, as the immediate future state ν transition probability: Pβ(ν) only depends on the present state μ. The Metropolis Algorithm is actually a version of Markov Chain Monte Carlo simulation, and since we use single-spin-flip dynamics in the Metropolis Algorithm, every state can be viewed as having links to exactly L other states, where each transition corresponds to flipping a single spin site to the opposite dipole. [8] Furthermore, since the energy equation Hσ change only depending on the nearest neighbors interaction influence 'J', we can view the Ising model as a form of Voter Model
One dimension[edit]
The thermodynamic limit exists as soon as the interaction decay is J_{ij} \sim |i-j|^{-\alpha} with α > 1.[9]
• In the case of ferromagnetic interaction J_{ij} \sim |i-j|^{-\alpha} with 1< α < 2 Dyson proved, by comparison with the hierarchical case, that there is phase transition at small enough temperature.[10]
• In the case of ferromagnetic interaction J_{ij} \sim |i-j|^{-2} , Fröhlich and Spencer proved that there is phase transition at small enough temperature (in contrast with the hierarchical case).[11]
• In the case of interaction J_{ij} \sim |i-j|^{-\alpha} with α > 2 (that includes the case of finite range interactions) there is no phase transition at any positive temperature (i.e. finite β) since the free energy is analytic in the thermodynamic parameters.[9]
• In the case of nearest neighbor interactions, E. Ising provided an exact solution of the model. At any positive temperature (i.e. finite β) the free energy is analytic in the thermodynamics parameters and the truncated two-point spin correlation decays exponentially fast. At zero temperature, (i.e. infinite β), there is a second order phase transition: the free energy is infinite and the truncated two point spin correlation does not decay (remains constant). Therefore T = 0 is the critical temperature of this case. Scaling formulas are satisfied.[12]
Ising's exact solution[edit]
In the nearest neighbor case (with periodic or free boundary conditions) an exact solution is available. The energy of the one-dimensional Ising model on a lattice of L sites with periodic boundary conditions is
H(\sigma)=-J\sum_{i=1,\ldots,L} \sigma_i \sigma_{i+1} - h \sum_i \sigma_i
where J and h can be any number, since in this simplified case J is a constant representing the interaction strength between the nearest neighbors and h is the constant external magnetic field applied to lattice sites. Then the free energy is
f(\beta, h)=-\lim_{L\to \infty} \frac{1}{\beta L} \ln (Z(\beta))=-\frac{1}{\beta} \ln\left(e^{\beta J} \cosh \beta h+\sqrt{e^{2\beta J}(\sinh\beta h)^2+e^{-2\beta J}}\right)
and the spin-spin correlation is
\langle \sigma_i \sigma_j\rangle-\langle \sigma_i \rangle\langle\sigma_j\rangle=C(\beta)e^{-c(\beta)|i-j|}
where C(β) and c(β) are positive functions for T > 0. For T → 0, though, the inverse correlation length, c(β), vanishes.
The proof of this result is a simple computation.
If h = 0, it is very easy to obtain the free energy in the case of free boundary condition, i.e. when
Then the model factorizes under the change of variables
\sigma'_j=\sigma_j\sigma_{j-1} \qquad j\ge 2.
That gives
Z(\beta) =\sum_{\sigma_1,\ldots, \sigma_L} e^{\beta J\sigma_1\sigma_2}\; e^{\beta J\sigma_2\sigma_3}\; \cdots e^{\beta J\sigma_{L-1}\sigma_L}= 2\prod_{j=2}^L \sum_{\sigma'_j} e^{\beta J\sigma'_j} =2\left[ e^{\beta J}+e^{-\beta J}\right]^{L-1}.
Therefore the free energy is
f(\beta,0)=-\frac{1}{\beta } \ln\left[e^{\beta J}+ e^{-\beta J}\right].
With the same change of variables
\langle \sigma_{j}\sigma_{j+N}\rangle=\left[\frac{e^{\beta J}- e^{-\beta J}}{e^{\beta J}+ e^{-\beta J}}\right]^N
hence it decays exponentially as soon as T ≠ 0; but for T = 0, i.e. in the limit β → ∞ there is no decay.
If h ≠ 0 we need the transfer matrix method. For the periodic boundary conditions case is the following. The partition function is
Z(\beta)=\sum_{\sigma_1,\ldots, \sigma_L} e^{\beta h \sigma_1}e^{\beta J\sigma_1\sigma_2}\; e^{\beta h \sigma_2}e^{\beta J\sigma_2\sigma_3}\; \cdots e^{\beta h \sigma_L}e^{\beta J\sigma_L\sigma_1}= \sum_{\sigma_1,\ldots, \sigma_L} V_{\sigma_1,\sigma_2}V_{\sigma_2,\sigma_3}\cdots V_{\sigma_L,\sigma_1}.
The coefficients V_{\sigma, \sigma'}'s can be seen as the entries of a matrix. There are different possible choices: a convenient one (because the matrix is symmetric) is
V_{\sigma, \sigma'} = e^{\frac{\beta h}{2} \sigma} e^{\beta J\sigma\sigma'} e^{\frac{\beta h}{2} \sigma'}
V=\begin{bmatrix} e^{\beta(h+J)}&e^{-\beta J}\\ e^{-\beta J}&e^{-\beta(h-J)} \end{bmatrix}.
In matrix formalism
Z(\beta)={\rm Tr} V^L= \lambda_1^L + \lambda_2^L= \lambda_1^L\left[1+ \left(\frac{\lambda_2}{\lambda_1}\right)^L\right]
where λ1 is the highest eigenvalue of V, while λ2 is the other eigenvalue:
and |λ2| < λ1. This gives the formula of the free energy.
The energy of the lowest state is −L, when all the spins are the same. For any other configuration, the extra energy is equal to the number of sign changes as you scan the configuration from left to right.
{p \over 1-p} = e^{-2\beta}.
\langle S_i S_j \rangle \,\propto\, e^{-p|i-j|}.
Z = \sum_{\mathrm{configs}} e^{\sum_k S_k} = \prod_k (1 + p ) = (1+p)^L.
The logarithm divided by L is the free energy density:
\beta f = \log(1+p) = \log\left( 1 + {e^{-2\beta}\over 1+e^{-2\beta}} \right),
which is analytic away from β = ∞. A sign of a phase transition is a non-analytic free energy, so the one-dimensional model does not have a phase transition.
Two dimensions[edit]
• In the ferromagnetic case there is a phase transition: at low temperature, Peierls argument proves positive magnetization for the nearest neighbor case and then, by Griffiths inequality, also when longer range interactions are added; while, at high temperature, cluster expansion gives analyticity of the thermodynamic functions.
• In the nearest-neighbor case, the free energy has been exactly computed by Onsager, through the equivalence of the model with free fermions on lattice. The spin-spin correlation functions has been computed by McCoy and Wu.
Onsager's exact solution[edit]
The partition function of the Ising model in two dimensions on a square lattice can be mapped to a two-dimensional free fermion. This allows the specific heat to be calculated exactly. Onsager obtained the following analytical expression for the magnetization as a function of temperature:
M = \left(1-\left[\sinh\left(\log(1+\sqrt{2})\frac{T_c}{T}\right)\right]^{-4}\right)^{\frac{1}{8}}
T_c = \frac{2J}{k_B\log(1+\sqrt{2})}.
Transfer matrix[edit]
\sum_S \exp\biggl(\sum_{ij} S_{i,j} S_{i,j+1} + S_{i,j} S_{i+1,j}\biggr).
U = e^{i H \Delta t}
U^N = (e^{i H \Delta t})^N = \int DX e^{iL}
T_{C_1 C_2}.
The configuration in each slice is a one-dimensional collection of spins. At each time slice, T has matrix elements between two configurations of spins, one in the immediate future and one in the immediate past. These two configurations are C1 and C2, and they are all one-dimensional spin configurations. We can think of the vector space that T acts on as all complex linear combinations of these. Using quantum mechanical notation:
|A\rangle = \sum_S A(S) |S\rangle
where each basis vector |S\rangle is a spin configuration of a one-dimensional Ising model.
Z= \mathrm{tr}(T^N).
T in terms of Pauli matrices[edit]
T can be written in terms of these:
\sum_i A \sigma^x_i + B \sigma^z_i \sigma^z_{i+1}
Spin flip creation and annihilation operators[edit]
Just as in the one-dimensional case, we will shift attention from the spins to the spin-flips. The σz term in T counts the number of spin flips, which we can write in terms of spin-flip creation and annihilation operators:
\sum C \psi^\dagger_i \psi_i. \,
1. moves a spin-flip one unit to the right
2. moves a spin-flip one unit to the left
3. produces two spin-flips on neighboring sites
4. destroys two spin-flips on neighboring sites.
Writing this out in terms of creation and annihilation operators:
\sigma^x_i = D {\psi^\dagger}_i \psi_{i+1} + D^* {\psi^\dagger}_i \psi_{i-1} + C\psi_i \psi_{i+1} + C^* {\psi^\dagger}_i {\psi^\dagger}_{i+1}.
Carrying out the diagonalization produces the Onsager free energy.
Onsager's formula for spontaneous magnetization[edit]
Onsager (1949) obtained the following formula for the spontaneous magnetization M of a two-dimensional Ising ferromagnet
M = \left(1 - \left[\sinh 2\beta E_1 \sinh 2\beta E_2\right]^{-2}\right)^{\frac{1}{8}}.
A complete derivation was later given by Yang (1952), using Szegő's limit formula for Toeplitz determinants, proved in 1951 in response to Onsager's work.[13][6] In this formula the total energy of Onsager's lattice model is given by
E=-E_1 \sum_{j,k} S_{j,k}S_{j,k+1} - E_2\sum_{j,k} S_{j,k} S_{j+1,k}
and β−1 = kT where k is Boltzmann's constant and T is the absolute temperature.
Three and four dimensions[edit]
In three dimensions, the Ising model was shown to have a representation in terms of non-interacting Fermionic lattice strings by Alexander Polyakov. In dimensions near four, the critical behavior of the model is understood to correspond to the renormalization behavior of the scalar phi-4 theory (see Kenneth Wilson).
More than four dimensions[edit]
Local field[edit]
\beta F = \int d^dx \left[ A H^2 + \sum_{i=1}^{d} Z_i (\partial_i H)^2 + \lambda H^4 ... \right].
On a square lattice, symmetries guarantee that the coefficients Zi of the derivative terms are all equal. But even for an anisotropic Ising model, where the Z's in different directions are different, the fluctuations in H are isotropic in a coordinate system where the different directions of space are rescaled.
On any lattice, the derivative term
Z_{ij} \partial_i H \partial_j H
is a positive definite quadratic form, and can be used to define the metric for space. So any translationally invariant Ising model is rotationally invariant at long distances, in coordinates that make Zij = δij. Rotational symmetry emerges spontaneously at large distances just because there aren't very many low order terms. At higher order multicritical points, this accidental symmetry is lost.
Since βF is a function of a slowly spatially varying field. The probability of any field configuration is:
P(H) \propto e^{ - \int d^dx \left[ AH^2 + Z |\nabla H|^2 + \lambda H^4 \right]}.
The statistical average of any product of H's is equal to:
\langle H(x_1) H(x_2)\cdots H(x_n) \rangle = { \int DH P(H) H(x_1) H(x_2) \cdots H(x_n) \over \int DH P(H) }.
Z = \int DH e^{ \int d^dx \left[ A H^2 + Z |\nabla H|^2 + \lambda H^4 \right]}
Dimensional analysis[edit]
F = \int d^dx A H^2.
F= \int d^dx \left[ t H^2 + \lambda H^4 + Z (\nabla H)^2 \right],
where t is a parameter which goes through zero at the transition.
Since t is vanishing, fixing the scale of the field using this term makes the other terms blow up. Once t is small, the scale of the field can either be set to fix the coefficient of the H4 term or the (∇H)2 term to 1.
To find the magnetization, fix the scaling of H so that λ is one. Now the field H has dimension −d/4, so that H4ddx is dimensionless, and Z has dimension 2−d/2. In this scaling, the gradient term is only important at long distances for d ≤ 4. Above four dimensions, at long wavelengths, the overall magnetization is only affected by the ultralocal terms.
There is one subtle point. The field H is fluctuating statistically, and the fluctuations can shift the zero point of t. To see how, consider H4 split in the following way:
H(x)^4 = -\langle H(x)^2\rangle^2 + 2\langle H(x)^2\rangle H(x)^2 + \left(H(x)^2 - \langle H(x)^2\rangle\right)^2
{\partial \over \partial H } \left( t H^2 + \lambda H^4 \right ) = 2t H + 4\lambda H^3 = 0
To find the behavior of fluctuations, rescale the field to fix the gradient term. Then the length scaling dimension of the field is 1−d/2. Now the field has constant quadratic spatial fluctuations at all temperatures. The scale dimension of the H2 term is 2, while the scale dimension of the H4 term is 4−d. For d < 4, the H4 term has positive scale dimension. In dimensions higher than 4 it has negative scale dimensions.
This is an essential difference. In dimensions higher than 4, fixing the scale of the gradient term means that the coefficient of the H4 term is less and less important at longer and longer wavelengths. The dimension at which nonquadratic contributions begin to contribute is known as the critical dimension. In the Ising model, the critical dimension is 4.
\langle S(x)S(y)\rangle \propto \langle H(x)H(y)\rangle = G(x-y) = \int {dk \over (2\pi)^d} { e^{ik(x-y)}\over k^2 + t }
valid when xy is large. The function G(xy) is the analytic continuation to imaginary time of the Feynman propagator, since the free energy is the analytic continuation of the quantum field action for a free scalar field. For dimensions 5 and higher, all the other correlation functions at long distances are then determined by Wick's theorem. All the odd moments are zero, by +/− symmetry. The even moments are the sum over all partition into pairs of the product of G(xy) for each pair.
\langle S(x_1) S(x_2) ... S(x_{2n})\rangle = C^n \sum G(x_{i1},x_{j1}) G(x_{i2},X_{j2}) \ldots G(x_{in},x_{jn})
The critical two-point function[edit]
&&\left(-\nabla_x^2 + t\right) \langle H(x)H(y) \rangle &= 0 \\
\rightarrow {} && \nabla^2 G(x) + tG(x) &= 0
E = \nabla G
away from the origin:
\nabla \cdot E = 0
since G is spherically symmetric in d dimensions, E is the radial gradient of G. Integrating over a large d−1 dimensional sphere,
\int d^{d-1}S E_r = \mathrm{constant}
This gives:
E = {C \over r^{d-1} }
and G can be found by integrating with respect to r.
G(r) = {C \over r^{d-2} }
The constant C fixes the overall normalization of the field.
G(r) away from the critical point[edit]
\nabla^2 G + t G = 0 \to {1 \over r^{d - 1}} {d \over dr} \left( r^{d-1} {dG \over dr} \right) + t G(r) = 0
For r small compared with \sqrt{t}, the solution diverges exactly the same way as in the critical case, but the long distance behavior is modified.
G(x) = \int d\tau {1 \over \left(\sqrt{2\pi\tau}\right)^d} e^{-{x^2 \over 4\tau} - t\tau}
G(k) = \int d\tau e^{-(k^2 - t)\tau} = {1 \over k^2 - t}
This is the inverse of the operator ∇2t in k space, acting on the unit function in k space, which is the Fourier transform of a delta function source localized at the origin. So it satisfies the same equation as G with the same boundary conditions that determine the strength of the divergence at 0.
The integral representation immediately shows that G(r) is positive, since it is represented as a weighted sum of positive Gaussians. It also gives the rate of decay at large r, since the proper time for a random walk to reach position τ is r2 and in this time, the Gaussian height has decayed by e^{-t\tau} = e^{-tr^2}. The decay factor appropriate for position r is therefore e^{-\sqrt t r}.
A heuristic approximation for G(r) is:
G(r) \approx { e^{-\sqrt t r} \over r^{d-2}}
Symanzik polymer interpretation[edit]
4−ε dimensions – renormalization group[edit]
F= \int d^4 x \left[ {Z \over 2} |\nabla H|^2 + {t\over 2} H^2 + {\lambda \over 4!} H^4 \right] \,
Wilson renormalization[edit]
Under rescaling, when the system is shrunk by a factor of (1+b), the t coefficient scales up by a factor (1+b)2 by dimensional analysis. The change in t for infinitesimal b is 2bt. The other two coefficients are dimensionless and don't change at all.
\nabla^2 H + t H = - {\lambda \over 6} H^3.
This equation is an identity inside any correlation function away from other insertions. After integrating out the modes with Λ < k < (1+b)Λ, it will be a slightly different identity.
Since the form of the equation will be preserved, to find the change in coefficients it is sufficient to analyze the change in the H3 term. In a Feynman diagram expansion, the H3 term in a correlation function inside a correlation has three dangling lines. Joining two of them at large wavenumber k gives a change H3 with one dangling line, so proportional to H:
\delta H^3 = 3H \int_{\Lambda<|k|<(1 + b)\Lambda} {d^4k \over (2\pi)^4} {1\over (k^2 + t)}
The integral should be split into two parts:
\int dk {1 \over k^2} - t \int dk { 1\over k^2(k^2 + t)} = A\Lambda^2 b + B b t
the first part is not proportional to t, and in the equation of motion it can be absorbed by a constant shift in t. It is caused by the fact that the H3 term has a linear part. part is independent of the value of t. Only the second term, which varies from t to t, contributes to the critical scaling.
\delta t = \left(2 - {B\lambda \over 2} \right)b t
But λ also changes. The change in lambda requires considering the lines splitting and then quickly rejoining. The lowest order process is one where one of the three lines from H3 splits into three, which quickly joins with one of the other lines from the same vertex. The correction to the vertex is
\delta \lambda = - {3 \lambda^2 \over 2} \int_k dk {1 \over (k^2 + t)^2} = -{3\lambda^2 \over 2} b
\delta \lambda = - 3 B \lambda^2 b
{dt \over t} &= \left(2 - {B\lambda \over 2}\right) b \\
{d\lambda \over \lambda} &= {-3 B \lambda \over 2} b
The coefficient B is determined by the formula
B b = \int_{\Lambda<|k|<(1+b)\Lambda} {d^4k\over (2\pi)^4} {1 \over k^4}
And is proportional to the area of a three-dimensional sphere of radius λ, times the width of the integration region bΛ divided by Λ4
B= (2 \pi^2 \Lambda^3) {1\over (2\pi)^4} { b \Lambda} {1 \over b\Lambda^4} = {1\over 8\pi^2}
Wilson–Fisher point[edit]
To investigate three dimensions starting from the four-dimensional theory should be possible, because the intersection probabilities of random walks depend continuously on the dimensionality of the space. In the language of Feynman graphs, the coupling doesn't change very much when the dimension is changed.
G(x-y) = \int d\tau {1 \over t^{d\over 2}} e^{{x^2 \over 2\tau} + t \tau}
In dimension 4−ε, the coupling λ has positive scale dimension ε, and this must be added to the flow.
{d\lambda \over \lambda} = \varepsilon - 3 B \lambda
{dt \over t} = 2 - \lambda B
\lambda = {\varepsilon \over 3B}
where the scale dimensions of t is altered by an amount λB = ε/3.
The magnetization exponent is altered proportionately to:
\tfrac{1}{2} \left( 1 - {\varepsilon \over 3}\right)
which is .333 in 3 dimensions (ε = 1) and .166 in 2 dimensions (ε = 2). This is not so far off from the measured exponent .308 and the Onsager two dimensional exponent .125.
Infinite dimensions – mean field[edit]
The idea is that if each spin is connected to a large number of spins, only the average number of + spins to − spins is important, since the fluctuations about this mean will be small. The mean field H is the average fraction of spins which are + minus the average fraction of spins which are −. The energy cost of flipping a single spin in the mean field H is ±2JNH. It is convenient to redefine J to absorb the factor N, so that the limit N → ∞ is smooth. In terms of the new J, the energy cost for flipping a spin is ±2JH.
This energy cost gives the ratio of probability p that the spin is + to the probability 1−p that the spin is −. This ratio is the Boltzmann factor.
{p\over 1-p} = e^{2\beta JH}
so that
p = {1 \over 1 + e^{-2\beta JH} }
The mean value of the spin is given by averaging 1 and −1 with the weights p and 1−p, so the mean value is 2p−1. But this average is the same for all spins, and is therefore equal to H.
H = 2p - 1 = { 1 - e^{-2\beta JH} \over 1 + e^{-2\beta JH}} = \tanh (\beta JH)
The solutions to this equation are the possible consistent mean fields. For βJ < 1 there is only the one solution at H = 0. For bigger values of β there are three solutions, and the solution at H = 0 is unstable.
For βJ = 1 + ε, just below the critical temperature, the value of H can be calculated from the Taylor expansion of the Hyperbolic tangent:
H = \tanh(\beta J H) = (1+\varepsilon)H - {(1+\varepsilon)^3H^3\over 3}
H = \sqrt{3\varepsilon}
H = {\partial (\beta F) \over \partial h} = (1+A\varepsilon) H + B H^3 + \cdots
Whatever A and B are, so long as neither of them is tuned to zero, the sponetaneous magnetization will grow as the square root of ε. This argument can only fail if the free energy βF is either non-analytic or non-generic at the exact β where the transition occurs.
But the spontaneous magnetization in magnetic systems and the density in gasses near the critical point are measured very accurately. The density and the magnetization in three dimensions have the same power-law dependence on the temperature near the critical point, but the behavior from experiments is:
H \propto \varepsilon^{0.308}
This is also true in two dimensions, where
H \propto \varepsilon^{0.125}
Low dimensions – block spins[edit]
Migdal-Kadanoff renormalization[edit]
Write the two-dimensional Ising model with an infinite number of possible higher order interactions. To keep spin reflection symmetry, only even powers contribute:
E = \sum_{ij} J_{ij} S_i S_j + \sum J_{ijkl} S_i S_j S_k S_l \ldots.
By translation invariance,Jij is only a function of i-j. By the accidental rotational symmetry, at large i and j its size only depends on the magnitude of the two-dimensional vector ij. The higher order coefficients are also similarly restricted.
e^{J (N_+ - N_-)} + e^{J (N_- - N_+)} = 2 \cosh(J[N_+ - N_-])
where N± is the number of neighbors which are ±. Ignoring the factor of 2, the free energy contribution from this odd site is:
F = \log(\cosh[J(N_+ - N_-)]).
\Delta F = \ln(\cosh[4J]).
3J' = \ln(\cosh[4J]).
Lattice gas[edit]
A coarse model is to make space-time a lattice and imagine that each position either contains an atom or it doesn't. The space of configuration is that of independent bits Bi, where each bit is either 0 or 1 depending on whether the position is occupied or not. An attractive interaction reduces the energy of two nearby atoms. If the attraction is only between nearest neighbors, the energy is reduced by −4JBiBj for each occupied neighboring pair.
The density of the atoms can be controlled by adding a chemical potential, which is a multiplicative probability cost for adding one more atom. A multiplicative factor in probability can be reinterpreted as an additive term in the logarithm – the energy. The extra energy of a configuration with N atoms is changed by μN. The probability cost of one more atom is a factor of exp(−βμ).
So the energy of the lattice gas is:
E = - \frac{1}{2} \sum_{\langle i,j \rangle} 4 J B_i B_j + \sum_i \mu B_i
E = - \frac{1}{2} \sum_{\langle i,j \rangle} J S_i S_j - \frac{1}{2} \sum_i (4 J - \mu) S_i
For lattices where every site has an equal number of neighbors, this is the Ising model with a magnetic field h = (zJ−μ)/2, where z is the number of neighbors.
Application to neuroscience[edit]
Following the general approach of Jaynes,[15][16] a recent interpretation of Schneidman, Berry, Segev and Bialek,[17] is that the Ising model is useful for any model of neural function, because a statistical model for neural activity should be chosen using the principle of maximum entropy. Given a collection of neurons, a statistical model which can reproduce the average firing rate for each neuron introduces a Lagrange multiplier for each neuron:
E = - \sum_i h_i S_i
E= - \tfrac{1}{2} \sum_{ij} J_{ij} S_i S_j - \sum_i h_i S_i
where J_{ij} are not restricted to neighbors. Note that this generalization of Ising model is sometimes called the quadratic exponential binary distribution in statistics. This energy function only introduces probability biases for a spin having a value and for a pair of spins having the same value. Higher order correlations are unconstrained by the multipliers. An activity pattern sampled from this distribution requires the largest number of bits to store in a computer, in the most efficient coding scheme imaginable, as compared with any other distribution with the same average activity and pairwise correlations. This means that Ising models are relevant to any system which is described by bits which are as random as possible, with constraints on the pairwise correlations and the average number of 1s, which frequently occurs in both the physical and social sciences.
Spin Glasses[edit]
With the Ising model the so-called spin glasses can also be described, by the usual Hamiltonian \hat H=-\frac{1}{2}\,\sum J_{i,k}\,S_i\,S_k, where the S-variables describe the Ising spins, while the Ji,k are taken from a random distribution. For spin glasses a typical distribution chooses antiferromagnetic bonds with probability p and ferromagnetic bonds with probability 1−p. These bonds stay fixed or "quenched" even in the presence of thermal fluctuations. When p=0 we have the original Ising model. This system deserves interest in its own; particularly one has "non-ergodic" properties leading to strange relaxation behaviour.| Much attention has been also attracted by the related bond and site dilute Ising model, especially in two dimensions, leading to intriguing critical behavior.[18]
See also[edit]
1. ^ See Gallavotti (1999), Chapters VI-VII.
2. ^ Ernst Ising, Contribution to the Theory of Ferromagnetism
3. ^ See Baierlein (1999), Chapter 16.
4. ^
5. ^
6. ^ a b Montroll, Potts & Ward 1963, pp. 308–309
7. ^ a b c d e f g h i j Newman MEJ, Barkema GT, "Monte Carlo Methods in Statistical Physics, Clarendon Press, 1999
8. ^ Teif V.B. (2007). "General transfer matrix formalism to calculate DNA-protein-drug binding in gene regulation". Nucleic Acids Res. 35: e80. doi:10.1093/nar/gkm268.
9. ^ a b Ruelle (1969). Statistical Mechanics:Rigorous Results. New York: W.A. Benjamin Inc.
10. ^ Dyson, F.J. (1969). "Existence of a phase-transition in a one-dimensional Ising ferromagnet". Comm. Math. Phys. 12: 91–107. Bibcode:1969CMaPh..12...91D. doi:10.1007/BF01645907.
11. ^ Fröhlich, J.; Spencer, T. (1982). "The phase transition in the one-dimensional Ising model with 1/r 2 interaction energy.". Comm. Math. Phys. 84.
12. ^ Baxter, Rodney J. (1982), Exactly solved models in statistical mechanics*, London: Academic Press Inc. [Harcourt Brace Jovanovich Publishers], ISBN 978-0-12-083180-7, MR 690578
13. ^ McCoy & Wu 1973, p. 245
14. ^ J. J. Hopfield (1982), "Neural networks and physical systems with emergent collective computational abilities", Proceedings of the National Academy of Sciences of the USA 79 (8): 2554–2558, Bibcode:1982PNAS...79.2554H, doi:10.1073/pnas.79.8.2554, PMC 346238, PMID 6953413.
15. ^ Jaynes, E. T. (1957), "Information Theory and Statistical Mechanics", Physical Review 106 (4): 620, Bibcode:1957PhRv..106..620J, doi:10.1103/PhysRev.106.620.
16. ^ Jaynes, Edwin T. (1957), "Information Theory and Statistical Mechanics II", Physical Review 108 (2): 71, Bibcode:1957PhRv..108..171J, doi:10.1103/PhysRev.108.171.
17. ^ Elad Schneidman, Michael J. Berry, Ronen Segev and William Bialek (2006), "Weak pairwise correlations imply strongly correlated network states in a neural population", Nature 440 (7087): 1007–1012, arXiv:q-bio/0512013, Bibcode:2006Natur.440.1007S, doi:10.1038/nature04701, PMC 1785327, PMID 16625187.
18. ^ J-S Wang, W Selke, VB Andreichenko, and VS Dotsenko (1990), "The critical behaviour of the two-dimensional dilute model", Physica A 164: 221–239, Bibcode:1990PhyA..164..221W, doi:10.1016/0378-4371(90)90196-Y
External links[edit]
|
__label__pos
| 0.826438 |
Katyuri kings
From Wikipedia, the free encyclopedia
(Redirected from Katyuri Kings)
Jump to: navigation, search
There have been numerous different claims of origin. Badri Dutt Pandey is among those who believe the Katyurs were originally from Ayodhya, while others trace their origins back to the Kunindas, having found coins from the Kuninda period. Rahul Sankrityayan traces their ancestry to Kshasha and Shaka stock, who were in India before the first century BCE.[1]
The Katyuri dynasty was founded by Vashudev Katyuri, also called Vasu Dev or Basu Dev, according to traditions, but his name is not found in any inscriptions and an ancient Basdeo temple at Joshimath is attributed to Vasu Dev.[2] Vasu Dev was of Buddhist origin, but later followed Brahminical practices and the brahminical practices of Katyuri kings in general is sometimes attributed to a vigorous campaign of Adi Shankara (788-820 CE).[3] Originally from Joshimath, during their reign they dominated lands of varying extent from the 'Katyur' (modern day Baijnath) valley in Kumaon, between 7th and 11th centuries C.E., and established their capital at Baijnath in Bageshwar district; which was then known as Kartikeyapura and lies in the centre of 'Katyur' valley. Brahmadev mandi (a trading / business center in a flat area of the then Katyuri kingdom) in the Kanchanpur District of Nepal was established by Katyuris king Brahma Deo (Brahma Dev). Brahmadeo Mandi still exists by this name.
Later offshoots[edit]
The Rajbar dynasty of Askot in Pithoragarh, was set up in the 1279 AD, by a branch of the Katyuri Kings, headed by Abhay Pal Deo, who was the grandson of Katyuri king, Brahm Deo. The dynasty ruled the region until it became part of the British Raj through the treaty of Sighauli in 1816. The Doti Kingdom was another strong offshoot of Katyuri dynasty. They were known as Rainka Maharaj, presently Doti is a part of Nepal. Another branch was the Mahson-Mahuli kingdom in eastern U.P., founded by one of Abhay Pal Deo's sons, Alakh Deo.
The period of certain Katyuri rulers, is generally determined as below, although there is some ambiguity in respect to exact number of years ruled by each King. 1. Vasu dev( ) 2. Basantana Dev (850-870 CE) 3. Kharpar Dev (870-880 CE) 4. Abhiraj Dev (880-890 CE) 5. Tribhuvanraj Dev (890-900 CE) 6. Nimbarta Dev (900-915 CE) 7. Istanga (915-930 CE) 8. Lalitasura Dev (930-955 CE) 9. Bhu Dev (955-970 CE) 10. Salonaditya (970-985 CE) 11. Ichchhata Dev (985 -1000 CE) 12. Deshat Dev (1000 -1015 CE) 13. Padmata Dev (1015-1045 CE) 14. Subhiksharaja Dev (1045-1060 CE) 15. Dham Dev and 16. Bir Dev (Very short period)[6]
Builders of temples[edit]
1. ^ O.C.Handa. pp.22-26
2. ^ O.C.Handa. p 25.
3. ^ O.C.Handa p.26
4. ^ 9th-11th century
6. ^ O.C.Handa. p.30-31
|
__label__pos
| 0.704391 |
How Far Is It from England to Australia?
England is approximately 10562 miles (16997 km) from Australia; this is the direct, air distance between these two places. When Australia was a colony of England, sea routes were the most common and feasible route used but these were impractical as it would take several months to reach Australia.
5 Additional Answers
Australia is a country as well as a continent in itself while England is a country in Western Europe. The distance between England and Australia is around 9533.00 miles or 15341.46 kilometres but would vary with specific locations in England or Australia.
From England to Australia is 10556 miles. This is the equivalent of 16,973.41km. You can convert these distances on a number of calculator sites.
The distance between England and Australia is approximately 16,898 kilometres. That is between London and Melbourne in Australia. Australia is a country located to the southern Hemisphere and comprises of the mainland continent of Australia and Tasmania. England is an island country in the UK.
The distance between Sydney, Australia and Manchester, England is roughly 17,000km. From London, to Sydney, the total distance covered by air would be approximately 16,983.04km. Australia refers to a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania and numerous smaller islands in the Indian and Pacific Oceans.
The distance between Sydney, Australia and London, England, United Kingdom, is approximately 10562 miles (16997 km) (9178 nautical miles). Going by plane is the quickest possible means.
Q&A Related to "How Far Is It from England to Australia"
About 20,000 kms.
Depending on what your destination is from New Zealand to Australia, the distance would range from 300 miles to 1,600 miles. The distance is not that great if traveling close by.
1. Determine the appropriate shipment option. There are three ways to ship a car overseas: roll on and roll off, or RORO as it is commonly called, consolidation in a 40-foot container
Here it is: LHR - SIN QF10 departs 21h30 arrives 17h30 12h43m duration SIN - DRW QF272 departs 18h20 arrives 21h20 4h27m duration Total flight time: 17h Total Travel time: 17h50
Explore this Topic
The distance between Australia and England is approximately 16,978 kilometres or 10,550 miles. Australia is the world's sixth-largest country by total area and ...
The approximate flying distance from England London to Melbourne Australia is 17,009 Kilometres or 10,570 miles. You can use flight or ship since the Country is ...
The distance between Australia and United Kingdom is about 15,287 kilometres which is equivalent to about 9499 miles. United Kingdom is a sovereign state situated ...
|
__label__pos
| 0.995449 |
The Deathly Hallows Text Sticker by AngryMongo
The Deathly Hallows Text Sticker by
The fashioning of the Hallows, using the text to form each one.
harry, potter, deathly hallows, hp, sorcerers, stone, philosophers, wand, elder, cloak, invisibility, death, reaper, brothers, tale, wizard, beedle, bard, movie, quote, text, book, pop culture, typography
View Full Profile
|
__label__pos
| 0.997404 |
Last updated on March 15, 2014 at 21:56 EDT
Acanthuridae Reference Libraries
Page 1 of about 20 Articles
Doctorfish Acanthurus chirurgus
2013-10-15 11:44:59
The Doctorfish (Acanthurus chirurgus), known also as the Doctorfish Tang, is a tropical marine fish that is common in the Atlantic Ocean. Achieving a maximum length of 39 centimeters, this fish gets it common name for the structures called “scalpels”, which are found on either side of the caudal peduncle. The “scalpel” is utilized during fights with other doctorfish and as a defense...
Ocean Surgeonfish Acanthurus bahianus
2013-03-22 13:10:32
The ocean surgeonfish is found around coral reefs of the Western Atlantic -- off the coasts of Florida, the Bahamas, the Caribbean Sea, the Gulf of Mexico, Bermuda, Brazil, and as far north as Massachusetts. This species will swim in schools, often with other species of surgeonfish. The oval shaped body of this surgeonfish is bluish-gray to dark brown with yellow markings and a dark marking...
Purple Tang Zebrasoma xanthurum
2013-02-10 07:39:55
Sailfin Tang Zebrasoma veliferum
2013-02-09 09:19:46
Whitespotted Surgeonfish Acanthurus guttatus
2013-02-03 10:08:43
Image Credit: National Park Service/Wikipedia The whitespotted surgeonfish is found in shallow water around rocky shore lines and exposed reefs in the Indo-Pacific. It is native to Mauritius, southern Japan, Indonesia, and northern Australia, but in 2003 it was discovered off the coast of Palm Beach, Florida. The spots of the whitespotted surgeonfish could act as a camouflage while it...
Twotone Tang Zebrasoma Scopas
2013-01-12 08:37:50
The twotone tang can also be referred to as the brown tang or the brush-tail tang. This species is native to the Indo-Pacific ranging from the east Africa coast to Japan, Malaysia, Indonesia, Australia, and the islands of Pitcaim and Lord Howe Island. A brown tang was discovered off the Fort Lauderdale, Florida coast in 2008, well beyond its native habitat. This fish is found at depths up...
Atlantic Blue Tang Acanthurus coeruleus
2012-05-22 10:10:55
The Atlantic Blue Tang (Acanthurus coeruleus), also known as the Atlantic Blue Tang Surgeonfish, is a species of surgeonfish commonly found in the Atlantic Ocean. It is found off the coast of Florida, the Bahamas, and other places around the Caribbean Sea, including Bonaire. It is very common in Belize, and particularly around Ambergis Caye. It is also found in the Gulf of Mexico and south...
Chocolate Surgeonfish Acanthurus pyroferus
2012-04-02 17:37:17
The Chocolate Surgeonfish, (Acanthurus pyroferus), is a species of Tang from the Indo-Pacific (excluding Hawaii) and is found primarily around steep shallow slopes near the coast with clear sand and hard corals. This species grows to about 10 inches long. It is sometimes known the Mimic Tang as an aquarium fish because of the juveniles striking coloration that resembles that of the Pygmy...
Elongate Surgeonfish Acanthurus mata
2012-04-02 17:23:07
The Elongate Surgeonfish, (Acanthurus mata), is a species of tropical fish found in the Indo-Pacific, and can be found as far north as Southern Japan and south to the Great Barrier Reef. Some also live as far west as South Africa and as far east as the Tuamotu Islands. Its main habitat is steep slopes around coral reefs. This is a light blue fish with numerous brown stripes running down the...
2007-02-21 16:29:02
Apistidae is a family of fish that includes the Waspfishes. They are 7.48-7.87 in (19 - 20 cm) in length.
|
__label__pos
| 0.741164 |
First: Mid: Last: City: State:
Christian Andreen
By subscribing to USA-People-Search.com, you can find Christian Andreen quickly and easily. With your membership, you'll have access to the billions of public records stored in our database. Our easy-to-use interface makes it easy for you to locate Christian Andreen and gather their contact information.
There could be several people with the same name as Christian Andreen. To make it easier to access the right Christian Andreen simply enter as many details as you can remember about Christian Andreen such as phone numbers and past addresses. Browse the refined results, and once you find the Christian Andreen you want, take a look at their profile.
Name/AKAsAgeLocationPossible Relatives
|
__label__pos
| 0.954189 |
Secret Spokesmodels: Guess The Celebs Who Voiced These Ads
These stars have had their faces pasted all over billboards and tabloids, but occasionally they hide their gorgeous complexions from the masses. This includes the dashing George Clooney, the hilarious Ty Burrell and so many others. We’ve got ads from 15 big celebrities who’ve concealed their identities for popular commercials. Can you peg the famous voices?
|
__label__pos
| 0.95058 |
Kent State: what happened and why
Front Cover
Fawcett, 1971 - Education - 512 pages
17 Reviews
From inside the book
What people are saying - Write a review
User ratings
5 stars
4 stars
3 stars
2 stars
1 star
Review: Kent State: What Happened and Why
User Review - Goodreads
I haven't read the other major works on this topic (the early accounts by Joe Eszterhas and Peter Davies, and William Gordon's more recent study) for comparison, but this is one heck of a gripping ...
Review: Kent State: What Happened and Why
User Review - Goodreads
This was a hard book to read at the time since it was about the truth. Michener's story's were about history but not so real as Kent State and so present day when it came out. But it had to be written and he did it well.
Related books
A banker takes a chance
The bars on Water Street
33 other sections not shown
Common terms and phrases
About the author (1971)
Bibliographic information
|
__label__pos
| 0.797272 |
See also: déduction
From Middle French déduction, from Latin deductio
deduction (plural deductions)
1. That which is deducted; that which is subtracted or removed
2. A sum that can be removed from tax calculations; something that is written off
You might want to donate the old junk and just take the deduction.
3. A conclusion; that which is deduced, concluded or figured out
He arrived at the deduction that the butler didn't do it.
4. The ability or skill to deduce or figure out; the power of reason
Through his powers of deduction, he realized that the plan would never work.
5. (logic) A process of reasoning that moves from the general to the specific, in which a conclusion follows necessarily from the premises presented, so that the conclusion cannot be false if the premises are true.
6. A conclusion reached by this process
Last modified on 10 January 2014, at 20:33
|
__label__pos
| 0.872281 |
Roger Atle W. Kårstad Plus
Bergen, Norway
User Stats
Profile Images
User Bio
Speedrider, Speedflyer and Psychologist.
Living and working in Bergen, Norway. With Voss and western Norway as my playground.
Now flying for Åsnes, check out
External Links
1. Petter Lahlum
2. Dave Turner
3. Rolf Dale
4. geir odden
5. Egil gjeraldstveit
6. Trond Bjelde
7. Morten Knapstad
|
__label__pos
| 0.993757 |
Where in Your Body Would You Find the Anvil and the Stirrup?
The anvil and stirrup are parts of the ear. The anvil and stirrup two of three tiny bones found in the middle ear which transmits the vibration received by the outer ear to the inner ear. The third bone is called the hammer.
Q&A Related to "Where in Your Body Would You Find the Anvil..."
there is no such bone
What is the Ear? Alex, May i have History for 400 ***Daily Dubble***
Stirrup is a small bone found in the middle ear. No details available for amber. The anvil is another small bone in the middle ear
In the ear. These three are ear ossicles which means small bones or small pieces of bone like substance. Anonymous
|
__label__pos
| 0.999316 |
View Full Version : Strange ideas of the origin of the universe, etc?
January 12th, 2009, 04:11 AM
Have you ever come across strange random thoughts or brainstorms that something strange or mysterious could hold a much greater value in knowledge or physical existence?
(warning, serious mental brain-farts ahead)
It's mathematically impossible to find the square root of a negative number. This is because a square is the result of two equal numbers (which are called square root) and negative numbers can only be brought about by multiplying a positive number and a negative number. However, I hypothesize the existence of this "negative square root." There are two branching scales of integers off of zero, positive numbers and negative numbers. What if there was a 3rd scale unknown or incomprehensible to us? If there was, I'm sure the square root of a negative number would be the number in the "third scale." Maybe understanding such a thing could make us understand existence more?
Discuss/submit your own random thoughts. I'll probably come back with more brain-farts later.
January 12th, 2009, 06:49 AM
While I have no 'strange ideas' of my own to share, I'd like to comment on yours.
It's an interesting theory, but something doesn't seem quite right to me. While humans may not have invented actual number (as in multiplicities of an object/objects), we did invent the numeral system and mathematics, which includes square roots. What I don't understand is how we could possibly invent something incomprehensible to ourselves? There may be something extremely similar to the square root of a negative number, but I don't think you could call it the "square root" without disregarding one or more of the characteristics that make a square root a square root.
I think you're on to something, though. The bit about this "3rd scale" is actually already a theory. This Wikipedia article (http://en.wikipedia.org/wiki/Complex_numbers) explains that "negative real numbers can be obtained by 'squaring' complex (imaginary) numbers."
My view on the whole thing is that complex numbers are exactly that: complex numbers. Not so complex that we should consider them imaginary, but complex enough that we either haven't discovered them (yet), or, as you said, they're "incomprehensible" to us.
Anyway, it's really hard to wrap your mind around. I'd rather just not think about, as the numeral system we have now seems to be working well enough. ;p
Black Omega Zero
January 12th, 2009, 06:26 PM
Rockets is right about the numbers' thing, but if you want the right answer, go to my post, in the "Do you believe in god or not" topic, my 1st post... not a strange idea, but the demonstrated truth!
I Laugh at your Misfortune!
January 13th, 2009, 12:13 PM
Well, I had one earlier today.
What is 0/0 ?
ALL numbers, when divided by themselves, equal 1. It's a general rule of mathematics.
2 = 2 x 1 = 2 x (0/0) = (2 x 0)/ 0 = 0/0 = 1
2 = 1
illogical, huh? So what is 0/0 equal to?
|
__label__pos
| 0.950072 |
Lesson on Manifest Destiny
Lesson 2
Google Document
Google Powerpoint
Manifest Destiny
Learning Essential Question
How did Manifest Destiny affect American expansion to the west?
Reading Material
Manifest Destiny
As a result of the Louisiana Purchase the United States instantly doubled in size. Now, with territory up to the Mississippi River claimed and settled as result of the Louisiana Purchase explored, Americans headed west in droves.
The idea of expanding American “civilization” to the “WILD AND UNTAMED” wilderness became very popular during this time period. That idea eventually turned into a belief.
Newspaper editor JOHN O'SULLIVAN coined the term "MANIFEST DESTINY" in 1845 to describe the essence of this belief. MANIFEST DESTINY was the belief that “God” destined the people of the United States to settle and expand from the east coast the west coast. It further stated that it was preordained that America would bring “CIVILIZATION” to those Native American tribes that were “deprived” of it.
In the song “America The Beautiful” captures this belief “AND CROWN THY GOOD WITH BROTHERHOOD FROM SEA TO SHINING SEA” (Figurative language which meant from the Atlantic Ocean to the Pacific Ocean. Proponents of Manifest Destiny used the belief to encourage the expansion of the country. However there were people who opposed the ideals of Manifest Destiny. The opponents argued that American Expansion would lead to the destruction of the way of “the way of life” of many Native American tribes.
The ideas of Manifest Destiny were captured in many of the artwork of the mid 1800’s. One of the most famous artworks is illustrated below
.... Student Educator Interpretation of the art
Connecting Activity
(Think, Pair, Share)
In a collaborative discussion create arguments that support or oppose Manifest Destiny.
Support Manifest Destiny
Against Manifest Destiny
Related Questions
1) If you were a member of a Native American tribe living in the Midwest how would you feel about the "pioneers" moving into and settling in your hunting lands?
2) How would you feel about the philosophy behind Manifest Destiny?
3) Would you view the settlers as saviors who are bringing "civilization" to the your lands or rather an evil invading force?
4) Would the United States involvement in places like Afghanistan and Iraq be considered an example of an EXTENSION of Manifest Destiny?
Art Challenge
This artwork was designed to promote support for American Expansion to the West. Create a drawing that either supports or opposes the principles behind Manifest Destiny.
Include in that poster a detailed explanation as to why your poster supports or denounces the principles behind Manifest Destiny.
Students will take on the persona of the groups connected to the Westward Expansion time period. This includes the Native American,a pioneer or settler, an immigrant working on the Transcontinental Railroad etc...
Write a fictional series of journal entries describing, from a child's view, some of the events, hardships and adventures of pioneers traveling west, the Native Americans, and the immigrants working on the railroads. (You can choose another writing style .)
In a series of political cartoons with a connecting newsletters showcase the treatment of the immigrants working on the railroads, particularly the Chinese immigrants who were often taken advantage of by the railroad companies, showcase the conflict between the Native Americans and the pioneers and gold miners when it came to the issue of land, the Buffalo and reservations
You are a reporter who is interviewing a member of the Native American tribes that are being displaced as a result of Westward Expansion. In a (Q) and (A) secession indicate how you would feel if your way of life was being threatened by the pioneers.
Create a technology presentation in which you showcase the timeline of the major events connected to Westward Expansion, the timeline will include the Louisiana Purchase, The Trial of Tears, the 1st wave of pioneers (prior to the Transcontinental Railroad), the 2nd wave of settlers after the completion of the railroad, The Wounded Knee Massacre (include information about the Ghost Dance) etc...
Manifest Destiny
The Expansion of the United States
gemps michelot,
Oct 12, 2011, 9:37 PM
|
__label__pos
| 0.897099 |
Shugo Chara! and Maid Sama! Crossovers
Twin Destinies by ChibiLenaLily
"Ayuzawa! Ayuzawa! Hang in there! Ayuzawa!" "Meet me at the car park at 10:00pm tonight." Rated T cuz me very paranoid
Rated: T - English - Friendship/Family - Chapters: 5 - Words: 4,172 - Favs: 3 - Follows: 1 - Updated: 1/23 - Published: 8/29/2013 - [Amu H., Tadase H.] [Misaki A., Kūkai S.]
7 Years Old Again by Suzume Batchii Taichi reviews
17 year old Takumi Usui and Ikuto Tsukiyomi due to their regrets about being forced to abandoning their Childhoods force them into states of Depression. One day after a chance incounter with one another thieir longing hearts and simbalanced wishies colliade and grant them just that.
Rated: T - English - Romance/Drama - Chapters: 3 - Words: 941 - Reviews: 2 - Favs: 7 - Follows: 7 - Updated: 12/27/2013 - Published: 10/21/2012 - Ikuto T., T. Usui
Idol sama is an Usui! by ChannieXOXO
Usui was just a walking beautiful mystery. Just a normal student and a 'perverted alien' at Seika High, what happens if a famous singer were to transfer to the school? Why are they so close? "Eh? What do you mean she's your little sister?"
Rated: T - English - Humor/Romance - Chapters: 1 - Words: 998 - Favs: 2 - Follows: 2 - Published: 11/17/2013 - Utau H., T. Usui
Reunion by Angelo del Cielo Nero reviews
Amu is Misaki childhood friend who moved away at the age of 7. She move to Seiyo Academy to avoid her ex-boyfriend. He found her. Then she moves to Seika with her twin brother. She met Ikuto there again. Ikuto was another friend of her and also a crush (was her enemy before Easter disband).
Rated: T - English - Friendship - Chapters: 10 - Words: 5,775 - Reviews: 6 - Favs: 7 - Follows: 9 - Updated: 8/19/2013 - Published: 12/26/2012 - Amu H., Ikuto T., Misaki A., T. Usui
The Sixth Guardian by Cammie LeInspiritedExotic reviews
Ayuzawa Misaki is in the world of Guardian Characters and Heart eggs, and she was told that she is the Sixth Guardian. A Kaichou Wa Maid Sama x Shugo Chara Fanfic! When characters from both manga/ anime come together. What are their adventures? Will there be a new loveline? :)
Rated: K+ - English - Romance/Adventure - Chapters: 1 - Words: 1,086 - Reviews: 4 - Favs: 3 - Follows: 5 - Published: 3/23/2013 - Amu H., Misaki A., T. Usui
Cousins and Maids by Micro Pikachu reviews
Hinamori Amu and her brother, Hinamori Hinata, are sent to the Ayuzawa Household, since their parents and sister are going to America for some time. What will happen when Amu becomes a waitress in a costume play café named Maid Latte like Ayuzawa Misaki to help Misaki's family? Full Summary and Pairings Inside!
Rated: T - English - Friendship - Chapters: 3 - Words: 10,181 - Reviews: 18 - Favs: 23 - Follows: 31 - Updated: 1/13/2013 - Published: 9/29/2012 - Amu H., Misaki A.
Idoru Gakuen by Yuna.Ichigo
Jai une très, mais alors très grande flemme d'en mettre, donc, je vais faire court: Yuna et Yumi sont deux lycéennes qui viennent d'être acceptées à Idoru Gakuen, un école d'art du spectacle très prestigieuse...Venez découvrir leurs aventures!
Rated: T - French - Humor/Romance - Chapters: 1 - Words: 2,287 - Published: 1/22/2012
|
__label__pos
| 0.974476 |
Latest Issue of Science News
Floating beads of water act as tiny test tubes
Superheated drops used to create nanoparticles
BUBBLE CHEMISTRY A phenomenon called the Leidenfrost effect helped convert gold salts in a water droplet (left) into gold nanoparticles (right).
Because the reaction requires only water, instead of hazardous or waste-producing solvents, the study authors say the technique offers a cheap, environmentally friendly way to manufacture nanoscale materials.
|
__label__pos
| 0.999471 |
Documentation Center
• Trial Software
• Product Updates
Convert prediction filter polynomial to reflection coefficients
k = poly2rc(a)
[k,r0] = poly2rc(a,efinal)
k = poly2rc(a) converts the prediction filter polynomial a to the reflection coefficients of the corresponding lattice structure. a can be real or complex, and a(1) cannot be 0. If a(1) is not equal to 1, poly2rc normalizes the prediction filter polynomial by a(1). k is a row vector of size length(a)-1.
[k,r0] = poly2rc(a,efinal) returns the zero-lag autocorrelation, r0, based on the final prediction error, efinal.
expand all
Find Reflection Coefficients from Prediction Filter Polynomial
Given a prediction filter polynomial, a, and a final prediction error, efinal, determine the reflection coefficients of the corresponding lattice structure and the zero-lag autocorrelation.
a = [1.0000 0.6149 0.9899 0.0000 0.0031 -0.0082];
efinal = 0.2;
[k,r0] = poly2rc(a,efinal)
k =
r0 =
If abs(k(i)) == 1 for any i, finding the reflection coefficients is an ill-conditioned problem. poly2rc returns some NaNs and provides a warning message in those cases.
More About
expand all
A simple, fast way to check if a has all of its roots inside the unit circle is to check if each of the elements of k has magnitude less than 1.
stable = all(abs(poly2rc(a))<1)
poly2rc implements this recursive relationship:
This relationship is based on Levinson's recursion [1]. To implement it, poly2rc loops through a in reverse order after discarding its first element. For each loop iteration i, the function:
1. Sets k(i) equal to a(i)
2. Applies the second relationship above to elements 1 through i of the vector a.
a = (a-k(i)*fliplr(a))/(1-k(i)^2);
See Also
| | | | |
Was this topic helpful?
|
__label__pos
| 0.964839 |
Government and society
The constitution of the Maldives was adopted in 2008. The head of state and government is the president, assisted by a vice president and a cabinet. The president and vice president are directly elected by universal suffrage to a maximum of two five-year terms. The cabinet consists of the vice president, government ministers, and the attorney general. With the exception of the vice president, members of the cabinet are appointed by the president.
The unicameral legislature, called the People’s Majlis, meets at least three times per year. Its members are elected to five-year terms from Male island and from each of the 20 atoll groups into which the country is divided for administrative purposes. The number of representatives from each administrative division is determined on the basis of population, with a minimum of two per division. The 2008 constitution established Islam as the official state religion. Non-Muslims cannot become citizens, and the People’s Majlis is prohibited from making any law that contravenes the tenets of Islam. Other governmental bodies include civil service and human rights commissions.
The highest legal authority is the Supreme Court. Its judges are appointed by the president in consultation with the Judicial Service Commission, a body of 10 members appointed or elected from various branches of the government and the general public. The Judicial Service Commission independently appoints all other judges. There are no judicial term limits; the mandatory retirement age is 70. All judges must be Sunni Muslims. The Supreme Court bases decisions upon the constitution and Maldives law; in cases in which applicable law does not exist, Sharīʿah (Islamic law) is considered. Other courts are the High Court and trial courts.
The archipelago was inhabited as early as the 5th century BCE by Buddhist peoples, probably from Sri Lanka and southern India. According to tradition, Islam was adopted in 1153 CE. Ibn Baṭṭūṭah, a notable North African traveler, resided there during the mid-1340s and described conditions at that time, remarking disapprovingly on the freedom of the women—a feature that has been noticeable throughout Maldivian history.
In the first years of the 21st century, Gayoom’s government embarked on a long-term plan to modernize and democratize the Maldives, particularly its economy and political system. The plan also identified the country’s legal system as inadequate. Beginning in 2003, wide-ranging reforms were instituted to improve human rights and the system of governance. A multiparty political system was created. In 2008 a new constitution was adopted that established greater governmental checks and balances, strengthened the powers of the legislature and judiciary, and allowed women to run for president. The country’s first multicandidate presidential election was held in October of that year, and Gayoom was reelected on the Maldivian People’s Party ticketformer political prisoner Mohamed Nasheed was elected president, thus ending Gayoom’s 30 years in office. One of Nasheed’s plans was to obtain a new homeland in the region to which the Maldive islanders could eventually be resettled, as the low-lying islands were believed to be under serious threat from rising sea levels.
|
__label__pos
| 0.907979 |
A. The unattended installation file contains details for settings that will apply to all machines, however there are some settings that you may want to be different from machine to machine, such as user name, computer name, TCP/IP address etc. This can be accomplished by producing a text file in a certain format, with different sections for each computer. The UDF file is used by specifying the /UDF:ID\[,<database file name>\]. An example UDF file would be
u1 = UserData,TCPIPParams
u2 = UserData,TCPIPParams
FullName = "John Savill"
ComputerName = SavillComp
ProductID = xxx-xxxxxx
IPAddress =
FullName = "Kevin Savill"
ComputerName = KevinComp
ProductID = xxx-xxxxxx
IPAddress =
The ID specified would be (in the case above) u1 or u2. If the above file was saved as udf.txt to perform an unattended installation for machine one you would use
winnt /b /s:z: /u:unattend.txt /UDF:u1,udf.txt
which would set the installation as user John Savill, computer name SavillComp and IP address If a parameter is specified in both the unattend answer file and the UDF the value in the UDF will be used. (The /b means its a floppyless installation and the /s specifies the source for the installation files and UDF etc. You would needed to have created the connection to z: already (net use z: //savillcomp/dist))
The structure of the UDF uses a subset of the sections available in the unattended answer file.
|
__label__pos
| 0.83019 |
Bohr Model of Nickel?
Bohr model for nickel refers to the four energy levels or shells of the transition metal. Nickel is a chemical element or metal that has an atomic number of 28, a cubic crystal structure and a chemical symbol of Ni.
Q&A Related to "Bohr Model of Nickel?"
Nickel has 4 energy shells. 2 in the first, 8 in the second, 16 in the third, and 2 in the final level. :
The Bohr Model is a model of an atom that Danish physicist Neils Bohr created in 1913. He used data from the atomic emission spectrum of hydrogen and made a model of the atom with
1. Create the nucleus of your Bohr atom by placing an orange or other round fruit on a flat surface. The nucleus consists of protons and neutrons clumped together, but for a simple
Please click on the link for a picture of the model.
Explore this Topic
A Bohr is a model of an atom introduced by Niels Bohr around 1913. He suggested that an atom consists of a positively charged centre surrounded by electrons. Bohr ...
The Bohr model is a model in atomic physics that consists of a small, positively charged nucleus surrounded by negatively charged electrons similar to the solar ...
The Bohr model is a type of illustration used to show the relationships among protons, electrons, and neutrons. The protons and neutrons share a nucleus, and they ...
|
__label__pos
| 0.965563 |
First: Mid: Last: City: State:
Erin Andros
Get instant access to more than a billion public records when you join USA-People-Search.com. Our sophisticated system will instantly generate accurate and extensive information about everyone named Erin Andros. From there, you can simply browse the results to find the exact Erin you're looking for.
Have you found Erin Andros yet? If not, just modify your search by including extra details, such as previous residences or other known aliases. Any minute piece of information you might have can assist your search. Once you locate the Erin Andros you're looking for, you'll be able to access all of the other data we have on them, including addresses, phone numbers, and email addresses.
Name/AKAsAgeLocationPossible Relatives
1. Andros, Erin B32 San Diego, CA
View Details
|
__label__pos
| 0.910742 |
TY - BOOK DB - /z-wcorg/ DP - http://worldcat.org ID - 62878732 LA - English T1 - Nasty girls A1 - Gray, Erick S., PB - St. Martin's Griffin CY - New York Y1 - 2006/// SN - 9780312349967 0312349963 AB - Camille, Jade, and Shy are best friends who have always had each others' backs until their drug-dealing boyfriends get caught up in a shooting that sends one boyfriend to jail. Jealousy, greed, revenge, and betrayal test the bonds of their friendship. ER -
|
__label__pos
| 0.987389 |
Rutger Vos > Bio-Phylo-0.56 > Bio::Phylo::Manual
Annotate this POD
View/Report Bugs
Bio::Phylo::Manual - High-level user guide
This is the manual for Bio::Phylo. Bio::Phylo is a perl5 package for phylogenetic analysis. The stable URL for the most recent distribution is
This manual is intended for readers who know how to program in perl and understand commonly-encountered concepts in phylogenetics. What is offered in this document is an overview of Bio::Phylo's functionality, not a tutorial or a reference of all functions.
For exhaustive API documentation, consult the embedded perlpod in the classes of this release, for example by issuing perldoc Bio::Phylo::IO (or some other class name) in a terminal window.
Note that Bio::Phylo uses inheritance to a great extent, such that any one object may inherit additional methods from a number of superclasses. In such cases, this will be noted in the "SEE ALSO" section at the bottom of that class's documentation. The Bio::Phylo documentation system rewards the methodical reader who follows these document links.
For installation instructions, read the README file in the root directory of the distribution.
The following sections will demonstrate some of the basic functionality, with immediate, useful results.
One-liners are perl statements that are executed directly on the command line, using the -e '...statements...' argument. Often, you'll include the -MFoo::Bar switch to include module Foo::Bar at runtime. (See perlrun for more info on executing the interpreter.) NOTE FOR WINDOWS USERS: in the following examples, switch the quotes around, i.e. use double quotes where single quotes are used and vice versa.
First steps
No concept is valid in Perl if it cannot be expressed in a one-liner. For the Bio::Phylo package, some operations can be performed using a single expression from the command line. Here are some examples.
Solution 1: downloading and converting Tree of Life data
perl -MBio::Phylo::IO=parse -e 'print parse->to_nexus' format tolweb as_project 1 url $URL
Assuming that the environment variable $URL has been set to point to a node in the XML web service of the Tree of Life (, this command will download the output, parse it, and print the parsed output as nexus. As an example, using this url:
Something like the following output would be produced:
[! Taxa block written by Bio::Phylo::Taxa 0.31_1520 on Thu Nov 25 20:49:54 2010 ]
'Bembidion alaskense'
'Bembidion argenteolum'
'Bembidion semenovi'
[! Trees block written by Bio::Phylo::Forest 0.31_1520 on Thu Nov 25 20:49:54 2010 ]
1 'Bembidion alaskense',
2 'Bembidion argenteolum',
3 'Bembidion semenovi';
TREE Tree2 = [&R] (((2,3),1));
So what is happening here? Firstly, we provide the -MBio::Phylo::IO switch, to which we add =parse, which means we import the parse function from Bio::Phylo::IO. This function is supplied with named arguments, which can also be provided on the command line, i.e. as part of the @ARGV array.
Secondly, we use the -e 'print parse->to_nexus' switch. Here we till perl to execute the parse function, transform its return value to nexus, and print that to STDOUT.
Following that, we provide the named command line arguments. format tolweb specifies that the input for the parse function is in the Tree of Life XML format. as_project 1 specifies that the parse function should return its contents as a newly created Bio::Phylo::Project object. url $URL specifies the data source to parse; in this case the data source lives at $URL. Other possible options for a data source are file with a file name, string with a string of phylogenetic data in some recognized format, or handle with an open file handle.
(This example requires the otherwise optional modules LWP::UserAgent and XML::Twig to be installed on your system.)
Solution 2: calculating tree balance
perl -MBio::Phylo::IO=parse -e 'print \
The -MModule switch is the equivalent of using use Module; in a script. Here we use the Bio::Phylo::IO module, which is Bio::Phylo's entry point into file parsing and file writing.
The -e switch is used to evaluate the subsequent expression. We parse a string, ((A,B),C);, of format newick. The parser returns a Bio::Phylo::Forest object (i.e. a set of trees, in this case a set of one). From this set we retrieve the first (and only) tree, and calculate Colless' imbalance, which returns a number, which we print to standard out.
This would print "1", because the tree is a ladder, and therefore completely unbalanced. Note how this example uses the standard interface for Bio::Phylo::IO as you would normally use it in code you write in a script or a module. As the arguments to the parse function can also be supplied in @ARGV (useful for one-liners or other processes that launch shell commands) the example can be rewritten as:
perl -MBio::Phylo::IO=parse -e 'print parse()->first->calc_imbalance' \
format newick string "((A,B),C);"
In this alternative invocation, note how the arguments to the parse call are now outside of the '...command...' quotes, making them "shell words", which for various reasons may not be preceded by dashes.
Sets of trees
You want a one-liner to iterate over a set of trees:
perl -MBio::Phylo::IO=parse -lne 'print \
parse(-format=>"newick",-string=>$_)->first->calc_i2' <file>
The -n switch wraps a "while(<>) { ... }" around the program, so the trees from file (that is, if they are one newick tree description per line) are copied into $_ one tree at a time. The -l switch appends a line break to the printed output.
Stringifying trees
You don't want a number printed to STDOUT, you want a tree:
If you try to print a tree object, what's written is something like Bio::Phylo::Forest::Tree=SCALAR(0x1a337dc) (that is, the memory address of the object reference). This is probably not what you want, so the tree object has a to_newick method that stringifies the tree to a newick string. Likewise, matrices, taxa and tree blocks can write a NEXUS block using to_nexus, and all of them can also be written to NeXML ( using to_xml and to a JSON mapping thereof using to_json.
Input and output
The Bio::Phylo::IO module is the unified front end for parsing and unparsing phylogenetic data objects. It is a non-OO module that optionally exports the parse and unparse subroutines into the caller's namespace, using the use Bio::Phylo::IO qw(parse unparse); directive. Alternatively, you can call the subroutines as class methods. The parse and unparse subroutines load and dispatch the appropriate sub-modules at runtime, depending on the -format argument.
Parsing trees
You want to create a Bio::Phylo::Forest::Tree object from a newick string.
use Bio::Phylo::IO;
# get a newick string from some source
my $tree_string = '(((A,B),C),D);';
# Call class method parse from Bio::Phylo::IO
my $tree = Bio::Phylo::IO->parse(
-string => $tree_string,
-format => 'newick'
# note: newick parser returns 'Bio::Phylo::Forest'
# Call ->first to retrieve the first tree of the forest.
print ref $tree, "\n"; # prints 'Bio::Phylo::Forest::Tree'
The Bio::Phylo::IO module invokes format specific parser and unparser modules. It is Bio::Phylo's front door for data input and output from files, raw strings and file handles.
In the solution the IO module calls the Bio::Phylo::Parsers::Newick parser which turns a tree description into a Bio::Phylo::Forest object. (Several other parser and unparser modules live in the Bio::Phylo::Parsers::* and Bio::Phylo::Unparsers::* namespaces, respectively.)
The returned forest object subclasses Bio::Phylo::Listable, as a forest models a list of trees that you can iterate over. By calling the -first> method, we get the first tree in the forest - a Bio::Phylo::Forest::Tree object (in the example it's a very small forest, consisting of just this single tree).
Parsing tables
You want to create a Bio::Phylo::Matrices::Matrix object from a string.
use Bio::Phylo::IO;
# parsing a table
my $table_string = qq(A,1,2|B,1,2|C,2,2|D,2,1);
my $matrix = Bio::Phylo::IO->parse(
-string => $table_string,
-format => 'table', # See Bio::Phylo::Parsers::Table
-type => 'STANDARD', # Data type
-fieldsep => ',', # field separator
-linesep => '|' # line separator
print ref $matrix, "\n"; # prints 'Bio::Phylo::Matrices::Matrix'
Here the Bio::Phylo::Parsers::Table module parses a string A,1,2|B,1,2|C,2,2|D,2,1, where the | is considered a record or line separator, and the , as a field separator. The default field and line separators are the tabstop character "\t" and the line break "\n".
Parsing taxa
You want to create a Bio::Phylo::Taxa object from a string.
use Bio::Phylo::IO;
# parsing a list of taxa
my $taxa_string = 'A:B:C:D';
my $taxa = Bio::Phylo::IO->parse(
-string => $taxa_string,
-format => 'taxlist',
-fieldsep => ':'
print ref $taxa, "\n"; # prints 'Bio::Phylo::Taxa'
Here the Bio::Phylo::Parsers::Taxlist module parses a string A:B:C:D, where the : is considered a field separator. The parser returns a Bio::Phylo::Taxa object. Note that the same result can be obtained by building the taxa object from scratch (a more feasible proposition than building trees or matrices from scratch):
use Bio::Phylo::Factory;
# first instantiate the factory...
my $factory = Bio::Phylo::Factory->new;
# ...then use it to create other objects, such as taxa blocks
my $taxa = $factory->create_taxa( -name => 'MyTaxa' );
# or taxa, (with names A, B, C and D), and add them to the taxa block
$taxa->insert( $factory->create_taxon( -name => $_ ) ) for qw(A B C D);
# and write out as a nexus block
print $taxa->to_nexus( -header => 1, -links => 1 );
This example uses the Bio::Phylo::Factory, which is an object that can create other objects. Here we have it create a Bio::Phylo::Taxa block, which we populate with four Bio::Phylo::Taxa::Taxon objects. We then write out the taxa block as nexus, complete with the #NEXUS header (this is optional so that we can combine multiple blocks in the same file), and a title, using the -links switch. The latter is a facility that only seems to be used by Mesquite ( and Bio::Phylo. It adds a "title" to the taxa block in the nexus output, and other blocks (character state matrices and tree blocks) refer to this using a "links" statement. This is useful if you want to have multiple taxa blocks in the same file and you want to distinguish them. Putting this all together, the output is thus:
[! Taxa block written by Bio::Phylo::Taxa 0.31_1520 on Thu Nov 25 21:31:58 2010 ]
TITLE MyTaxa;
The Bio::Phylo::Listable module is the superclass of all container objects. Container objects are objects that contain a set of objects of the same type. For example, a Bio::Phylo::Forest::Tree object is a container for Bio::Phylo::Forest::Node objects. Hence, the Bio::Phylo::Forest::Tree inherits from the Bio::Phylo::Listable class. You can therefore iterate over the nodes in a tree using the methods defined by Bio::Phylo::Listable.
Iterating over trees and nodes.
You want to access trees and nodes contained in a Bio::Phylo::Forest object.
use Bio::Phylo::IO qw(parse);
my $string = '((A,B),(C,D));(((A,B),C)D);';
my $forest = parse( -format => 'newick', -string => $string );
print ref $forest; # prints 'Bio::Phylo::Forest'
# access trees in $forest
foreach my $tree ( @{ $forest->get_entities } ) {
print ref $tree; # prints 'Bio::Phylo::Forest::Tree';
# access nodes in $tree
foreach my $node ( @{ $tree->get_entities } ) {
print ref $node; # prints 'Bio::Phylo::Forest::Node';
Bio::Phylo::Forest and Bio::Phylo::Forest::Tree are nested subclasses of the iterator class Bio::Phylo::Listable. Nested iterator calls (such as -get_entities>) can be invoked on the objects.
Iterating over taxa.
You want to access the individual taxa in a Bio::Phylo::Taxa object.
my $string = 'A|B|C|D|E|F|G|H';
my $taxa = parse(
-string => $string,
-format => 'taxlist',
-fieldsep => '|'
print ref $taxa; # prints 'Bio::Phylo::Taxa';
while ( my $taxon = $taxa->next ) {
print ref $taxon; # prints 'Bio::Phylo::Taxa::Taxon'
A Bio::Phylo::Taxa object is a subclass of the Bio::Phylo::Listable class. Hence, you could also call -get_entities> on the taxa object, which returns a reference to an array of taxon objects contained by the taxa object. Note however the shorthand:
while ( my $taxon = $taxa->next ) { ... }
Iterating over datum objects.
You want to access the datum objects contained by a Bio::Phylo::Matrices::Matrix object.
use Bio::Phylo::IO;
# parsing a table
-string => $table_string,
-type => 'STANDARD', # Data type
-fieldsep => ',', # field separator
-linesep => '|' # line separator
my $datum = $matrix->get_by_index( 0, -1 );
print ref $datum; # NOTE: prints 'ARRAY'!
The Bio::Phylo::Matrices::Matrix object subclasses the Bio::Phylo::Listable object. Hence, its iterator methods are applicable here as well. In the above example, the get_by_index method is used. With a single argument it returns a Bio::Phylo object. With multiple arguments the semantics are nearly identical to array slicing (see perldata), except that an array reference is returned. Bio::Phylo generally passes lists by reference (see perlref).
Simulating trees
The Bio::Phylo::Generator module simulates trees under various models of clade growth.
Generating Yule trees.
Here's how to generate a forest of ten trees with ten tips:
use Bio::Phylo::Generator;
my $gen = Bio::Phylo::Generator->new;
my $trees = $gen->gen_rand_pure_birth(
-trees => 10,
-tips => 10,
-model => 'yule'
print ref $trees; # prints 'Bio::Phylo::Forest'
Expected versus randomly drawn waiting times.
The generator object simulates trees under the Yule or the Hey model, returning. The gen_rand_pure_birth method call returns branch lengths drawn from the appropriate distribution, while gen_exp_pure_birth returns the expected waiting times (e.g. 1/n where n=number of lineages for the Yule model).
Filtering objects by numerical value.
To retrieve, for example, the nodes from a tree that are close to the root, call:
my @deep_nodes = @{ $tree->get_by_value(
-value => 'calc_nodes_to_root',
-le => 2
) };
Which retrieves the nodes no more than 2 ancestors away from the root. Any method that returns a numerical value can be specified with the -value flag. The -le flag specifies that the returned value is less-than-or-equal to 2.
Filtering objects by regular expression.
String values that are returned by objects can be filtered using a compiled regular expression. For example:
my @lemurs = @{ $tree->get_by_regular_expression(
-value => 'get_name',
-match => qr/[Ll]emur_.+$/
) };
Retrieves all nodes whose genus name matches Eulemur, Lemur or Hapalemur.
Drawing trees
You can create visualize tree objects using the Bio::Phylo::Treedrawer module:
use Bio::Phylo::Treedrawers;
use Bio::Phylo::IO;
my $treedrawer = Bio::Phylo::Treedrawers->new(
-width => 400,
-height => 600,
-shape => 'CURVY',
-mode => 'CLADO',
-format => 'SVG'
-format => 'newick',
-string => '((A,B),C);'
my $string = $treedrawer->draw;
Read the Bio::Phylo::Treedrawer perldoc for more info.
Tips and tricks
Generic metadata
You can append generic key/value pairs to any object, by calling $obj->set_generic( 'key' => 'value');. Subsequently calling $obj->get_generic('key'); returns 'value'. This is a very useful feature in many situations where you may want to attach, for example, results from analyses by outside programs (e.g. likelihood scores) to the tree objects they refer to. Likewise, multiple numbers (e.g. bootstrap values, posteriors, bremer values) can be attached to the same node in this way.
Perl objects
Object-oriented perl is a massive subject. To learn about the basic syntax of OO-perl, the following perldocs might be of interest:
Introduction to OO perl. Read at least this one if you have no experience with OO perl.
Details about perl objects.
Class data.
Advanced objects: "Tom's object-oriented tutorial for perl"
The "Bag'o Object Tricks" (the BOT).
The Bio::Phylo object model
The following sections discuss the nested objects that model phylogenetic information and entities.
The Bio::Phylo root object.
The Bio::Phylo object is never used directly. However, all other objects inherit from it, which means that all objects have getters and setters for their name, description, score. They can all return a globally unique ID, log messages, and keep track of more administrative things such as the version number of the release.
The Bio::Phylo::Forest::* namespace
According to Bio::Phylo, there is a Forest (which is modelled by the Bio::Phylo::Forest object), which contains Bio::Phylo::Forest::Tree objects, which contain Bio::Phylo::Forest::Node objects.
The Bio::Phylo::Forest::Node object
A node 'knows' a couple of things: its name, its branch length (i.e. the length of the branch connecting it and its parent), who its parent is, its next sister (on its right), its previous sister (on the left), its first daughter and its last daughter. Also, a taxon can be specified that the node refers to (this makes most sense when the node is terminal). These properties can be retrieved and modified by methods classified as ACCESSORS and MUTATORS.
From this set of properties follows a number of things which must be either true or false. For example, if a node has no children it is a terminal node. By asking a node whether it "is_terminal", it replies either with true (i.e. 1) or false (undef). Methods such as this are classified as TESTS.
Likewise, based on the properties of an individual node we can perform a query to retrieve nodes related to it. For example, by asking the node to "get_ancestors" it returns a list of its ancestors, being all the nodes and the path from its parent to, and including, the root. These methods are QUERIES.
Lastly, some CALCULATIONS can be performed by the node. By asking the node to "calc_path_to_root" it calculates the sum of the lengths of the branches connecting it and the root. Of course, in order to make all this possible, a node has to exist, so it needs to be constructed. The CONSTRUCTOR is the Bio::Phylo::Node->new() method.
Once a node has served its purpose it can be destroyed. For this purpose there is a DESTRUCTOR, which cleans up once we're done with the node. However, in most cases you don't have to worry about constructing and destroying nodes as this is handled by Bio::Phylo and perl for you.
For a detailed description of all the node methods, their arguments and return values, consult the node documentation, which, after install, can be viewed by issuing the "perldoc Bio::Phylo::Forest::Node" command.
The Bio::Phylo::Forest::Tree object
A tree knows very little. All it really holds is a set of nodes, which are there because of TREE POPULATION, i.e. the process of inserting nodes in the tree. The tree can be queried in a number of ways, for example, we can ask the tree to "get_entities", to which the tree replies with a list of all the nodes it holds. Be advised that this doesn't mean that the nodes are connected in a meaningful way, if at all. The tree doesn't care, the nodes are supposed to know who their parents, sisters, and daughters are. But, we can still get, for example, all the terminal nodes (i.e. the tips) in the tree by retrieving all the nodes in the tree and asking each one of them whether it "is_terminal", discarding the ones that aren't.
Based on the set of nodes the tree holds it can perform calculations, such as "calc_tree_length", which simply means that the tree iterates over all its nodes, summing their branch lengths, and returning the total.
The tree object also has a constructor and a destructor, but normally you don't have to worry about that. All the tree methods can be viewed by issuing the "perldoc Bio::Phylo::Forest::Tree" command.
The Bio::Phylo::Forest object
The object containing all others is the Forest object. It serves merely as a container to hold multiple trees, which are inserted in the Forest object using the "insert()" method, and retrieved using the "get_entities" method. More information can be found in the Bio::Phylo::Forest perldoc page.
The Bio::Phylo::Matrices::* namespace
Objects in the Bio::Phylo::Matrices namespace are used to handle comparative data, as single observations, and in larger container objects.
The Bio::Phylo::Matrices::Datum object
The datum object holds observations of a predefined type, such as molecular data, or continuous character states. The Datum object can be linked to a taxon object, to specify which OTU the observation refers to.
The Bio::Phylo::Matrices::Matrix object
The matrix object is used to aggregate datum objects into a larger, iterator object, which can be accessed using the methods of the Bio::Phylo::Listable class.
The Bio::Phylo::Matrices object
The top level opject in the Bio::Phylo::Matrices namespace is used to contain multiple matrix or alignment objects, again implementing an iterator interface.
The Bio::Phylo::Taxa::* namespace
Sets of taxa are modelled by the Bio::Phylo::Taxa object. It is a container that holds Bio::Phylo::Taxa::Taxon objects. The taxon objects at present provide no other functionality than to serve as a means of crossreferencing nodes in trees, and datum or sequence objects. This, however, is a very important feature. In order to be able to write, for example, files formatted for Mark Pagel's Discrete, Continuous and Multistate programs a taxa object, a matrix and a tree object must be crossreferenced.
The Bio::Phylo::Taxa object
The taxa object is analogous to a taxa block as implemented by Mesquite ( Multiple matrix objects and forests can be linked to a single taxa object, using $taxa-set_matrix( $matrix )>. Conversely, the relationship from matrix to taxa and from forest to taxa is a one-to-one relationship.
The Bio::Phylo::Taxa::Taxon object
Just as forests can be linked to taxa objects, so too can indidividual node and datum objects be linked to individual taxon objects. Again, the taxon can hold references to multiple nodes or multiple datum objects, but conversely there is a one-to-one relationship. There is a constraint on these relationships: a node can only refer to a taxon that belongs to a taxa object that the forest object that contains the node references:
|FOREST | The taxon and node objects can
| __________ | link to each other, because
| |TREE | | their containers do also.
| | ______ | |
| | |NODE | | |
| | |______| | |
| |_____^____| |
|_______|______| NO!
^ | ______________
____|__|__ |FOREST 'B' | The taxon object
|TAXA | | | __________ | cannot reference
| _____| | | |TREE | | forest 'A' while
| |TAXON | | | | ______ | | its container
| |______| | | | |NODE | | | references forest
|__________| | | |______| | | 'B'.
| |__________| |
|______________| ______________
^ |FOREST 'A' |
____|_____ | __________ |
|TAXA | | |TREE | |
| ______ | | | ______ | |
| |TAXON |------------>|NODE | | |
| |______| | | | |______| | |
|__________| | |__________| |
Trying to set the links in the example on the right will result in errors: "Attempt to link X to taxon from wrong block". So what happens if a taxon already links to a node in forest 'A', and you link its enclosing taxa block to forest 'B'? The links at the taxon and node level will be removed, and the link between forest and taxa object will be enforced, yielding the warning "Reset X references from node objects to taxa outside taxa block".
Unlike most other implementations of tree structures (or any other perl objects) the Bio::Phylo objects are truly encapsulated: Most perl objects are hash references, so in most cases you can do $obj-{'key'} = 'value'>. Not so for Bio::Phylo. The objects are implemented as 'InsideOut' objects. How they work exactly is outside of the scope of this document, but the upshot as that the state of an object can only be changed through its methods. This is a feature that helps keep the code base maintainable as this project grows. Also, the way it is implemented is more memory-efficient and faster than the standard approach. The encapsulation forces users of this module to use the documented interfaces of the objects. This, however, is a good thing: as long as the interfaces stay the same, any code using Bio::Phylo will continue to work, regardless of the implementation under the surface.
'Is-a' relationships: Inheritance
The objects in Bio::Phylo are related in various ways. Some objects inherit from superclasses. Hence the object is a special case of the superclass. This has important implications for the API: the documentation for each class only lists the methods defined locally in that class, not the methods of the superclasses. Therefore, many objects can do much more than would seem from their local POD. Always inspect the "SEE ALSO" section of any class's documentation to see if there are superclasses where more functionality might be defined.
'Has-a' relationships
Some objects contain other objects. For example, a Bio::Phylo::Forest::Tree contains Bio::Phylo::Forest::Node objects, a matrix object holds datum objects, and so on. The container objects all behave like Bio::Phylo::Listable objects: you can iterate over them (also recursively). The contains / container relationships implemented by Bio::Phylo are shown below:
______________ ________________
|FOREST | |MATRICES |
| __________ | | __________ |
| |TREE | | | |MATRIX | |
| | ______ | | | | ______ | |
| | |NODE | | | | | |DATUM | | |
| | |______| | | | | |______| | |
| |__________| | | |__________| |
|______________| |________________|
|TAXA |
| ______ |
| |TAXON | |
| |______| |
Named arguments when number of arguments >= 2.
When the number of arguments to a method call exceeds 1, named arguments are used. The order in which the arguments are specified doesn't matter, but the arguments must be all lower case and preceded by a dash:
use Bio::Phylo::Forest::Tree;
my $node = Bio::Phylo::Forest::Tree->new(
-name => 'PHYLIP_1',
-score => 123,
Type checking
Argument type is always checked. Numbers are checked for being numbers, names are checked for being sane strings, without '():;,'. Objects are checked for type. Internally, Bio::Phylo never checks type based on class name, for example using $obj-isa('Some::Class')>. Instead, object identity is validated using a system of constants defined in Bio::Phylo::Util::CONSTANT. If Bio::Phylo needs to test validate object type, it'll do something like:
use Bio::Phylo::Util::CONSTANT qw(:objecttypes);
use Bio::Phylo::Forest::Node;
my $node = Bio::Phylo::Forest::Node->new;
print "It's a node!" if $node->_type == _NODE_;
Hence, Bio::Phylo uses a form of "duck typing" ("if it walks like a duck, and quacks like a duck, it probably is a duck"), as opposed to one that is based on inheritance from a java-like interface, as is the convention in bioperl. Both systems have their advantages and drawbacks, but luckily they can coexist side by without problems.
As a new feature, a utility function is provided that does this type checking for you, returning true or throwing an exception (see below), so that the following will either succeed or die (so you might want to put it inside an eval{} block):
if ( looks_like_object( $node, _NODE_ ) ) {
# do something
Constructor arguments
All mutators (i.e. setters, methods called set_*) for a class and its superclasses can be accessed from the constructor. E.g. because the Bio::Phylo superclass of object Bio::Phylo::Forest::Node has a "set_name" method, you can pass the following to the constructor:
use Bio::Phylo::Forest::Node;
my $node = Bio::Phylo::Forest::Node->new( -name => "node1" );
The arguments will be passed up the inheritance tree, and will eventually be turned into method calls by the root class.
Retun values
Apart from scalar variables, all other return values are passed by reference, either as a reference to an object or to an array.
Lists returned as array references
Multiple return values are never returned as a list, always as an array reference:
my $nodes = $tree->get_entities;
print ref $nodes;
#prints ARRAY.
To receive nodes in @nodes, dereference the returned array reference (for clarity, all array dereferencing in this document is indicated by using braces in addition to this sigil):
my @nodes = @{ $tree->get_entities };
Returns self on mutators
Mutator method calls always return the modified object, and so they can be chained:
False but defined return values
When a value requested through an Accessor hasn't been set, the return value is undef. Here you should take care how you test. For example:
if ( ! $node->get_parent ) {
$root = $node;
This works as expected - object references are always "true", so if get_parent returns "false", $node has no parent - hence it must be the root. However:
if ( ! $node->get_branch_length ) {
# is there really no branch length?
if ( defined $node->get_branch_length ) {
# perhaps there is, but of length 0.
...warrants caution. Zero is evaluated as false-but-defined.
The Bio::Phylo modules throw exceptions that subclass Exception::Class. Exceptions are thrown when something exceptional has happened. Not when the value requested through an accessor method is undefined. If a node has no parent, undef is returned. Usually, you will encounter exceptions in response to invalid input.
Trying/Catching exceptions
If some method call returns an exception, wrap the call inside an eval block. The error now becomes non-fatal:
# try something:
eval { $node->set_branch_length('a bad value'); };
# handle exception, if any
if ($@) {
# do something, e.g.:
print $@->trace->as_string; # <- $@ is an object!
Stack traces
If an exception of a particular type is caught, you can print a stack trace and find out what might have gone wrong starting from your script drilling into the module code.
# exception caught.
if ( UNIVERSAL::isa( $@, 'Bio::Phylo::Util::Exceptions::BadNumber' ) ) {
# prints stack trace in addition to error
warn $@->error, "\n, $@->trace->as_string, "\n";
# further metadata from exception object
warn join ' ', $@->euid, $@->egid, $@->uid, $@->gid, $@->pid, $@->time;
As a new feature (from v.0.17 onwards) exceptions have become more descriptive, with a generic explanation of what the thrown exception class typically means added to the error message, and stack traces are printed out by default.
Exception types
Several exception classes are defined. The type of the thrown exception should give you a hint as to what might be wrong. The types are specified in the Bio::Phylo::Util::Exceptions perldoc.
Below is a list of things that hopefully will be implemented in future versions of Bio::Phylo.
More DNA sequence methods
Such as $seq->complement;. This would imply larger constant translation tables, including various tables for mtDNA and so on. Will probably be implemented, must likely using BioPerl tools.
Implement/improve access to TreeBASE, TolWeb and other databases. This could probably be done best using PhyloWS.
Test coverage is reasonable, but some of the newer features need to be exercised more.
Interoperability with BioPerl
The eventual aim of the Bio::Phylo project is to glue together the phylogenetics aspects of BioPerl (, Bio::NEXUS.
CPAN hosts a discussion forum for Bio::Phylo. If you have trouble using this module the discussion forum is a good place to start posting questions (NOT bug reports, see below):
Rutger Vos, Aki Mimoto, Klaas Hartmann, Jason Caravas, Mark Jensen and Chase Miller
web page:
Copyright 2005-2010 Rutger A. Vos, All Rights Reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
syntax highlighting:
|
__label__pos
| 0.823609 |
BEGIN:VCALENDAR VERSION:1.0 BEGIN:VEVENT CATEGORIES: SPECIAL OCCASION;TRAVEL;APPOINTMENT STATUS:NEEDS ACTION DTSTART:20120419T000000 DTEND:20120512T000000 SUMMARY:28 Seeds DESCRIPTION;ENCODING=QUOTED-PRINTABLE:Event Name: 28 Seeds=0D=0AEvent Url: Date Begin: 2012-04-19=0D=0AEvent Date End: 2012-05-12=0D=0A=0D=0AWhat happens when experimental theatre company Liars and Believers plunges headlong into a lustful, gluttonous, greedy, slothful, wrath-ridden, envious, prideful collaboration with texture-core steampunk phenomenon, Walter Sickert and the Army of Broken Toys? Let's just say, it's not the end of the world.=0D=0A=Oh wait, it is.=0D=0A=Based on the original radio play and album by Walter Sickert this apocalyptic sci-fi steampunk musical traces the precipitous decline of our species in an explosive display of light, sound and movement.=0D=0A= =0D=0A=This production contains language and adult themes, suitable for ages 15+ CLASS:PRIVATE PRIORITY:3 END:VEVENT END:VCALENDAR
|
__label__pos
| 0.958537 |
End of preview. Expand
in Data Studio
No dataset card yet
- Downloads last month
- 117