cahya/wikipedia-simple-en huggingface dataset:
Sigma

Sigma (uppercase/lowercase Σ σ ς) is the 18th letter of the Greek alphabet. It is used to represent the "s" sound in Ancient and Modern Greek. In the system of Greek numerals, it has a value of 200. Letters that came from it include the Roman S and Cyrillic С.

Mathematics 
The uppercase Σ is the shorthand symbol for summation (the symbol is also known as the summation operator). It is often used to condense Taylor series and to write out trigonometric functions such as sine, cosine, and tangent as series.

The lowercase σ is used to represent population standard deviation in statistics, and permutation function in abstract algebra.

Related pages 
 Stigma (letter)

References 

Greek alphabet
Tau

Tau (uppercase/lowercase Τ τ), is the letter of the Greek alphabet, used to represent the "t" sound in Ancient and Modern Greek. In the system of Greek numerals, it has a value of 300. Letters that came from it include the Roman T and Cyrillic Т.

Other Uses 

Some people want to use Tau in place of Pi, the special number that comes from circles. Tau would be equal to two times pi, or about 6.283.

These people want to use Tau because they think it would be easier for everyone to understand. There are many reasons in math why Tau could be useful or helpful. One of the simplest is that it would make learning about radians easier.

A radian is a way of measuring the angle of a circle. It says that the number of radians in an angle is equal to the length of the outside of the circle, or the 'arc length', that is covered by an angle, divided by the radius, or distance from the point in the center of a circle to anywhere on the outside (see the picture on the bottom right of the page).

If the distance covered around the outside of a circle is equal to the radius, than one radian is being covered. Around the whole outside of a circle, there are about 6.283 radians - or, Tau radians (Tau is just a number, like 0, or 7, or 100).

The advantage of this is that one quarter of a circle would simply become Tau / 4 radians, and one half of a circle Tau / 2 radians, which is more in line with our intuition on circles (see also the drawing below).

Not many people use Tau yet, but more and more are.

Related pages 

 Tau lepton

References 

Greek alphabet
Upsilon

Upsilon (uppercase/lowercase Υ υ) is the 20th letter of the Greek alphabet. It is used to represent the "u" sound in Ancient Greek and "i" in Modern Greek. In the system of Greek numerals, it has a value of 400. Letters that came from it include the Roman U, V and Y, and the Cyrillic У.

In mathematics, the uppercase  is used to represent the upsilon function (a variant of Riemann zeta function), while the lowercase  is used as a general variable. In physics, the uppercase  is used to represent an upsilon meson. In astrology, the same letter is used for the sign of Aries.

Related pages 
 U (Cyrillic)

References 

Greek alphabet
Vowel letters
Phi

Phi (uppercase/lowercase Φ φ), is the 21st letter of the Greek alphabet, used to represent the "ph" sound in Ancient Greek. This sound changed to "f" some time in the 1st century AD, and in Modern Greek the letter denotes the "f" sound. In the system of Greek numerals, it has a value of 500. The Cyrillic letter Ф came from Phi. In English, φ is pronounced like "f" but transliterated (re-written) as "ph" in words which originate in Ancient Greek. In those words which originate in Modern Greek, such as feta cheese, φ is transliterated as "f". The letter Phi is used to represent the golden ratio (which is about 1.618).

Related pages 
 Euler's totient function

References 

Greek alphabet
Chi (letter)

Chi (uppercase/lowercase Χ χ) is the 22nd letter of the Greek alphabet. It is used to represent the "ch" sound (as in Scottish "loch" or German "Bauch") in Ancient and Modern Greek. In the system of Greek numerals, it has a value of 600. Letters that came from it include the Roman X and Cyrillic Х.

In mathematics, the lowercase  is used to represent characteristic function, chi-square distribution in statistics and Euler characteristic in geometry.

Related pages 
 X (letter)

References 

Greek alphabet
Psi (letter)

Psi (uppercase/lowercase Ψ ψ) is the 23rd letter of the Greek alphabet. It is used to represent the "ps" sound in Ancient and Modern Greek. In the system of Greek numerals, it has a value of 700. Letters that came from it include Cyrillic Ѱ.

In mathematics, the uppercase  is used as a variable for sets of sentences (in logic), and the lowercase  is used to represent the sum of reciprocals of Fibonacci numbers. Other applications include the polygamma function, the gamma function and the super golden ratio.

Related pages 
 Phi

References 

Greek alphabet
Omega

Omega (uppercase/lowercase Ω ω) is the 24th and the last letter of the Greek alphabet. It stood for a long "o" sound in Ancient Greek. It still stands for "o" in Modern Greek, but there is no longer a difference between long and short vowels, so it sounds the same as Omicron. In the system of Greek numerals, it stands for the number 800. 

There was also once a letter "Omega" Ѡ in the Cyrillic alphabet. It was there so people could spell Greek names both in Cyrillic and in Greek in the same way. However, this letter is no longer used today.

In mathematics, the uppercase omega Ω is used in big-Omega notation (a variant of big-O notation). It is also used to represent the Omega constant. In electromagnetism and engineering, the uppercase Ω is used as the symbol for ohms, which are the units of electrical resistance. In physics and other sciences, the lowercase ω is often used to represent angular frequency. 

In modern English, the phrase "From alpha to omega" expresses the idea of "everything".

Related pages 
 Alpha

References 

Greek alphabet
Vowel letters
Sampi

Sampi or Disigma is a mysterious Greek symbol. Its meaning is still debated today. Some believe it to be a replacement of 'san'. Before that, it was a letter that was used in the Greek alphabet in a few Greek cities in the 5th century BC. At that time, it looked like  or . It was probably pronounced like "ts" or "tch" in the dialect of those cities. Over time, it was changed from  to  or  and at last to . Eventually, the letter came out of use, while it was still used to denote "900" in the system of Greek numerals.

Greek alphabet
Aliteracy

The problem of aliteracy is the state of being able to read but being uninterested in doing so. Teachers and school librarians are trying to deal with this problem.

Fortune magazine article
Stratford P. Sherman wrote, in a November 18, 1991 article in Fortune magazine, about the need for America to read more.  He began by saying that most Americans could not understand the article.  He referred to a study by John P. Robinson, a sociology professor at the University of Maryland, showing that the average American at that time spent only 24 minutes per day in reading.  He mentioned the continuing decline in newspaper sales, and referred to a guess by Leonard Riggio, CEO of Barnes & Noble, that 50% of books sold by his company were never read.  He quoted Samuel Robert Lichter, director of the Center for Media and Public Affairs, on his preference for the ease of turning on the TV instead of reading a book.  Sherman went on, in his article, to mention the growing need for skillful commmunication in American business but also the decreasing quality of the same activity.  He quoted Monsanto CEO Richard Mahoney on the importance of reading in helping a business manager to see connections between events.  He described print media as being first among different media with respect to (1) the amount of information conveyed by so few widely understood symbols, (2) portability, (3) suitability for the user's own speed of use, and (4) economical distribution of broad and deep information which can be used immediately.

Sherman said that Motorola was making preparations to pay $5,000,000 to teach workers reading and other basic skills, and that, since 1982, Ford Motor Company had already sent 32,000 workers on a similar program. He said that Simon & Schuster  predicted a market of $500,000,000 per year in the sales of remedial programs to corporations.  He quoted a spokesman for the National Association of Broadcasters as saying that "the biggest predictor of scholastic success is the time parents spend reading to their children."  However, Sherman said that the amount of time thus spent meant that the outlook was "not bright".

Related pages
 Book
 Dyslexia
 Literacy

Other websites 
 Reducing "Alliteracy" in H.S. Students by Joanne Collison

Literature
L'Anse aux Meadows

L'Anse aux Meadows is a historical settlement on the island of Newfoundland in eastern Canada. It was settled by Vikings from Greenland, Iceland, and Norway around the year 1000, almost 500 years before Christopher Columbus came to the Americas. It is the only known Viking place in North America outside of Greenland. The remains of the settlement were discovered in 1960, and were declared a UNESCO World Heritage Site in 1978. 

World Heritage Sites in Canada
Settlements in Newfoundland and Labrador
The Wealth of Nations

An Inquiry into the Nature and Causes of the Wealth of Nations is better known simply as The Wealth of Nations. It was written by Adam Smith in 1776, who was a Scottish man. It looks at division of work, following self-interest, and freedom of trade.

The book was not the beginning of classical economics, and market economics. Smith said that if everyone did what was best for themselves, the result would be best for society. Before that, economics was about the king's personal interests, and the wealth of a nation was measured by the king's treasury or by the gold and silver in the country. 

Smith said what's important is what's best for the whole nation, and that wealth should be measured by the yearly income of the nation. He wanted to discover how wealth can grow, and how people could do things to support that growth. Smith's book said land, labour, and capital were the three "factors of production" and the main contributors to a nation's wealth.

Prices naturally adjust to having more or less of something: supply and demand. If there is too much of something (more supply), prices go down so that people have more reason to buy it. If a lot of people want something (high demand), there may not be enough of it (scarcity); there will be a competition among the people who want to buy it, and some people will agree to pay more to get what they want, and prices go up. 

Smith said markets should be free. At the time, some big companies (like the East India Company) were controlled by the government. Sometimes the rulers made laws that were good for themselves but not for workers or customers. For example, in the American colonies, colonists could grow cotton but were not allowed to make clothing from it. They had to ship it to England to be made into clothing, then buy it back after it was finished. Smith said this was bad for individuals and for society. He thought it was better for money to flow freely and naturally between buyers and sellers without outside interference. Money would naturally go to the sellers who made the best product at the best price. This way if people did what was best for them, it would end up being best for society as a whole, almost like an "invisible hand" was guiding everything.

References

18th-century books
Non-fiction books
Economics books
La Dessalinienne

La Dessalinienne (The Dessalines Song) is the national anthem of Haiti, honoring Jean-Jacques Dessalines. The lyrics (words of the song) were written by Justin Lhérisson and its music composed by Nicolas Geffrard; it was adopted in 1904.

Lyrics

References

Other websites 
 La Dessalinienne (mp3)

Haiti
National anthems
1904 establishments
1900s establishments in North America
Establishments in Haiti
New Castle, Indiana

New Castle is a city in Henry County, Indiana, 44 miles (71 km) east of Indianapolis, on the Big Blue River. In 1900, 3,406 people lived in the town; in 1910, 9,446; in 1920, 14,458; and in 1940, 16,620. The population was 17,780 in 2000. The city is the county seat of Henry County. New Castle is home to New Castle Fieldhouse, the largest high school  in the world.

References

Other websites
 City of New Castle

News & Media 
 The Courier-Times
 New Castle Online 

Cities in Indiana
County seats in Indiana
Pop art

Pop art is a modern art movement that developed in the 1950s and 60s. It was created by the Scottish sculptor and artist Eduardo Paolozzi in London, 1952. Andy Warhol, Robert Indiana and Roy Lichtenstein are examples of pop artists.

Pop art has themes and techniques drawn from popular mass culture, such as advertising and comic books. Pop art employs images of popular as opposed to elitist culture in art.

Origin 
The Independent Group (IG), founded in London in 1951, is regarded as the starting point of the pop art movement. They were a gathering of young painters, sculptors, architects, writers and critics who were challenging modernist approaches to culture as well as traditional views of "fine art". The group discussions centered on popular culture implications from such elements as mass advertising, movies, product design, comic strips, science fiction and technology.

At the first Independent Group meeting in 1952, co-founding member, artist and sculptor Eduardo Paolozzi presented a lecture using a series of collages titled Bunk! that he had assembled during his time in Paris between 1947–1949. This material consisted of 'found objects' such as, advertising, comic book characters, magazine covers and various mass-produced graphics that mostly represented American popular culture. One of the images in that presentation was Paolozzi's 1947 collage, I was a Rich Man's Plaything, which includes the first use of the word "pop″, appearing in a cloud of smoke emerging from a revolver. After Paolozzi's seminal presentation in 1952, the IG focused on the imagery of American popular culture, particularly mass advertising.

Methods 
The artists use mechanical means of reproduction or rendering techniques which downplay the expressive hand of the artist.

Pop artists went for absolute clarity. Most forms were bordered with black lines as in comic books. The objects are often plain like a poster, and without perspective. The colours are clear, achromatic and primitive colours.

Objects of the everyday life get isolated and modified or processed in collages. Pop art is a connection between reality and art, handled with abstract means. Some of their catchwords are: popular, consumable, cheap, funny and outstanding.
 
Much of pop art is rather academic, as the unconventional organizational practices used often make it difficult for some to understand. Pop art and minimalism are considered to be the last modern art movements and so the precursors to postmodern art, or some of the earliest examples of postmodern art themselves.

Famous pop artists 

 Peter Blake
 Jim Dine
 James Gill
 Red Grooms
 Richard Hamilton
 Keith Haring

 David Hockney
 Robert Indiana
 Jasper Johns
 Roy Lichtenstein
 John McHale
 Claes Oldenburg

 Julian Opie
 Eduardo Paolozzi
 Peter Phillips
 Pietro Psaier
 Robert Rauschenberg
 Larry Rivers

 James Rizzi
 James Rosenquist
 George Segal
 Wayne Thiebaud 
 Andy Warhol
 John Wesley
 Tom Wesselmann

References
Museum of Modern Art

The Museum of Modern Art (MoMA) is a modern art museum in New York, New York, United States, on 53rd Street between Fifth and Sixth Avenues. It has been called the most important museum of modern art in the world. Some of the artists featured at the museum include Jackson Pollock, Vincent van Gogh, Andy Warhol and Robert Indiana.

References

Other websites 

 Museum of Modern Art official site
 Abby Aldrich Rockefeller: Patron of the modern
 New York Times, 2007: Donors Sweetened Director's Pay At MoMA, Prompting Questions Controversy over the compensation package of MoMA's Director, Glenn D. Lowry.
 Taniguchi and the New MOMA
 Museum Conservation Lab Renovation 

Art museums in the United States
Museums in New York City
Buildings and structures in Manhattan
Rankine scale

The Rankine scale is a thermodynamic (absolute) temperature scale. It is based around absolute zero. Rankine is similar to the Kelvin scale in that it starts at absolute zero and 0 °Ra is the same as 0 K but is different as a change of 1 °Ra is the same as a change of 1 °F (Fahrenheit) and not 1 °C (Celsius). Note that the abbreviation °R is ambiguous, as it can also refer to the Réaumur scale. 

The Kelvin and Rankine temperature scales are defined so that absolute zero is 0 kelvins (K) or 0 degrees Rankine (°R). The Celsius and Fahrenheit scales are defined so that absolute zero is −273.15 °C or −459.67 °F.

The Rankine scale was originally used in the United States.

Units of temperature
High fidelity

High fidelity or hi-fi is a way of describing a very good home music system. "High fidelity" means that the sound is as close to the original as possible with no changes or added noise. People who like hi-fi are sometimes called audiophiles. Hi-fi is often now called "high-end audio".

History 
In  the 1930s and 1940s, vacuum tubes were used to make radios and electronic amplifiers. Radio was becoming popular, and microphones, amplifiers and loudspeakers began to be sold. Manufacturers began to compete to produce the best product. A lot of research was done at Bell Laboratories and products were made by Western Electric.

Then a new kind of vinyl record with less noise and better sound was invented. Manufacturers began to call their equipment and records "high fidelity" to help sell them. In the 1950s, "hi-fi" became the popular term, replacing "phonograph" and "record player".  Rather than playing a record "on the phonograph," people would play it "on the hi-fi".

In the late 1950s and early 1960s, Westrex invented the stereo record that used two speakers. This led to more improvements in home audio. The word "stereo" replaced the word "hi-fi." Records were now played on "a stereo". 

Some people bought individual parts (separate speakers and amplifiers), and even built their own equipment. The term "high fidelity" is still used for very good music systems.

Other websites 
 
 A Dictionary of Home Entertainment Terms
 Renato Giussani: Optimal Stereo Soundstage and Imaging 
 The High Fidelity Museum

Sound
Stereo

Stereophonic sound, also simply called stereo, is the reproduction of sound using two or more audio  loudspeakers. This creates a pleasant and natural sound heard from various directions, as in natural hearing. 

The word "stereophonic" comes from Greek stereos = "solid" and phōnē = "sound". It was coined by Western Electric.

In popular usage, stereo usually means two-channel sound recording and sound reproduction using data from two speakers. The electronic device for playing back stereo sound is often called "a stereo".

Sound
Ely, Cambridgeshire

Ely (; IPA , rhyming with "freely") is a cathedral city in the East Cambridgeshire district of Cambridgeshire in the east of England and  north north-east of Cambridge.

Ely has been called a city for a long time because it has a cathedral. However, the Royal Charter making it a city was only issued in 1974. Ely's population was 15,102 in 2001. This means Ely is the third smallest city in England. Only after Wells in Somerset and the City of London which are smaller.

The University of Cambridge rowing team has a boathouse on the bank of the river and train there for the annual Boat Race against the University of Oxford.

The 1944 Boat Race was raced on the River Great Ouse near Ely, the only time it has not been held on the River Thames. The race was won by Oxford despite Cambridge being ahead early in the contest.

Landscape 
Ely is built on an clay which is one of the highest points in the Fens. This is very different to the West of Cambridgeshire which is made up of limestone. The river Great Ouse runs through the city, and is one of the longest rivers in the UK with many others flowing into it. The drainage area of the rivers that form the Great Ouse is around 6000 square miles (16,000 square kilometres). This is five times larger than the Fens itself The landscape was a large marsh until the 18th century, when much of the Fens was drained, making Ely no longer an island. Because of this, the ground around the city is very fertile and most of the region is used for farming. The marshes also had many different animals in them such as the Eel, which the city is named after.

Climate 
Cambridgeshire is one of the driest counties in Britain. It is protected from coastal wind from the east. It gets an average of 24 inches (600mm) of rain per year. Because of this, Cambridgeshire is warm in summer and cold and frosty in winter.

References 

Settlements in Cambridgeshire
Cities in England
Tube sound

Tube sound (or valve sound) is the sound produced by a vacuum tube-based audio amplifier.  All amplifiers distort to some degree; some audiophiles prefer the sound produced by tube amplifiers.  The reasons for the difference in sound between tube and solid state electronic devices is a continuing debate among audiophiles.

References 
Hamm, Russell O. Tubes Vs. Transistors: Is There An Audible Difference? in Journal of The Audio Engineering Society, presented September 14, 1972, at the 43rd Convention of the Audio Engineering Society, New York.
Rosenberg, Harvey (2004). Understanding Tube Electronics II .
Santo, Brian. Volume cranked up in amp debate in Electronic Engineering Times, Issue 817, October 3, 1994.

Sound
Audio technology
Derby (disambiguation)

Derby is the county town of Derbyshire. It may also refer to:

Places 
In Australia:
 Derby, Tasmania
 Derby, Western Australia

In South Africa:
 Derby, South Africa

In the United Kingdom:
 Derby Road railway station, Ipswich, England
 West Derby, Liverpool, England

In the United States:
 Derby, Colorado
 Derby, Connecticut
 Derby, Iowa
 Derby, Kansas
 Derby, New York
 Derby, Vermont
 Derby Line, Vermont

Sport 
 Derby County F.C., a football club currently playing in the Premier League
 Derby (horse race), a race usually restricted to three year old horses
 Epsom Derby
 German Derby
 Kentucky Derby
 New Zealand Derby
 Victoria Derby

 Local derby, a game between two neighbouring teams
 Demolition derby
 Roller derby
 Soap Box Derby
 Bike derby
 Fishing derby
 Home Run Derby

Other meanings 
 Apache Derby, a Java relational database management system from Apache Software Foundation (ASF)
 Earl of Derby, a title in the peerage of England
 Derby hat, another name for a bowler hat
 Derby shoe
 Derby cigarettes, a brand of cigarettes sold in some parts of Latin America
 Royal Crown Derby, a pottery factory in Derby, England
 Derby Missile, a beyond-visual-range (BVR) air-to-air missile developed by RAFAEL Armament Development Authority.
 Derby Records, a record label.
 Sage Derby cheese, a kind of cheese.
Chi

CHI could mean:

Chile, the long and narrow South American nation between the Andes and the Pacific Ocean.
Chicago, the IATA city code for a major US city (sometimes informally written "Chi" or "Chi-town"). Additionally, most Chicago sports teams can be called "CHI" or "Chi" when citing scores, etc.
 Chicago Bears, a National Football League team
 Chicago Blackhawks, a National Hockey League team
 Chicago Bulls, a National Basketball Association team 
 Chicago Cubs, a Major League Baseball team
 Chicago White Sox, a Major League Baseball team
 Child Health International, a UK based charity for children's health (especially Cystic Fibrosis) in poor countries
 Human-Computer Interaction, otherwise known as Computer-Human Interaction (CHI) 
 CHI, an annual, international academic conference on the topic of Computer-Human Interaction
 Chromosomal crossover, in homologous recombination, a viral DNA sequence called a "crossover hotspot instigator" (CHI)
CHI, Longwood University's, secret honorary society formed in 1900 in Farmville, Virginia
 Closed Head Injury, meaning the skull is not broken.
 Columbia Helicopters, Inc of Aurora, Oregon.  Manufacturer and Operator of heavy lift helicopters
 Chingford railway station, London; National Rail station code CHI

Chi 
Chi could mean:
 Chi, the Greek letter, Χ
 The Chi distribution, which is denoted by 
 The Chi-square distribution, which is denoted by 
Chi (kana), a letter used in the Japanese script Hiragana
 Chi (magazine), an Italian magazine based in Milan
 Chi Cheng (musician), Bassist for Deftones
 Chi McBride, actor
 Chi River in North-East Thailand
 Chi, a fictional character in the anime/manga series Chobits
 In Igbo mythology in Nigeria, Chi is a god or personification of an individual's fate
 Chi is an alleged life force in every thing
Mu

Mu can be:

Mu, Μ or μ, a letter in the Greek alphabet.
μ is used as a symbol for:
The SI prefix micro, meaning a factor of 10-6 (one millionth).
μ by itself is often used as the "unit" of strain, though in this context it retains its SI prefix meaning, which is interchangeable with "x 10-6" or "ppm" (parts per million).
μ by itself is an abbreviation for the unit micron. Both the term and the abbreviation should not be used. The preferred terms are µm and micrometre
In mathematics,
The arithmetic mean of a statistical population
The Möbius function
The least-fixed-point-operator
A degree of membership from a fuzzy set.
In chemistry,
The chemical potential
In physics, 
The coefficient of friction
The mobility coefficient
The permeability (electromagnetism) coefficient
The muon, an elementary particle
The standard gravitational parameter
The magnetic dipole moment
The linear density
Viscosity
Reduced mass
µTorrent, a freeware BitTorrent client for Microsoft Windows written in C++.
μZiq, An alias of Mike Paradinas. 

In Asian languages:
Mù, (), a Chinese surname
Mu (unit of area) (/), a Chinese unit of area
Mu (kana), represented by the Japanese kana  or 
Mu (negative) (), a Japanese word important in Zen koan practice

Mu may also refer to:
Muonium's atomic symbol 
Mu-metal, an alloy used for screening magnetic fields
Mu (lost continent), a mythical continent in the Pacific Ocean subsequently appearing in several books, films, and games
Mu (rocket), a Japanese rocket
Mu Dan, Chinese poet and translator
Mu Online, an online role-playing game
Mu La Flaga, a character from the anime Mobile Suit Gundam SEED
Aries Mu, a character from the cartoon Saint Seiya
Groupe Mu, an interdisciplinary Belgian group focusing on linguistics and rhetoric
Lemuria, a hypothetical lost continent

MU may stand for:
Mauritius' ISO 3166-1 alpha-2 country code
China Eastern Airlines's IATA code
Manchester United Football club
The Mothers' Union, global Anglican women's organisation
Monitor unit, a unit used in radiation therapy
Centimorgan or "map unit", a unit of recombinant frequency in genetics
Multiple unit, such as a rail diesel car
MU puzzle, a puzzle in Gödel, Escher, Bach
University of Mumbai, formerly called the University of Bombay
Marquette University
Marshall University
Miami University, a public university in Oxford, Ohio
Millersville University of Pennsylvania
Miskatonic University  
University of Missouri, a public university in Columbia, Missouri 
Mahidol University, a University in Thailand
Manipal University, a university in Karnataka, India
MU (70's band), an early 1970s psychedelic group led by Merrell Fankhauser and Jeff Cotton
MU (00's band), a 00's electro-punk group made up of producer Maurice Fulton and his wife Mutsumi Kanamori.
Mirror Universe (Star Trek), fictional parallel universe in which the plots of several Star Trek television episodes take place
Magic-User, a class type in D&D, HackMaster, and many fantasy RPGs
 Musician, an enlisted rating in the United States Navy
 Isuzu MU Wizard
 Micron Technology
Pi (disambiguation)

Pi (math), , or π, is the mathematical constant equal to a circle's circumference divided by its diameter.

Pi may also refer to:

Letter Pi (π)

Pi (letter), the Greek letter
Lowercase π:
 π (film), a 1998 film directed by Darren Aronofsky
  (pi function), the prime-counting function
 Pi bond
 Osmotic pressure
 A song from the Kate Bush album Aerial
 Shorthand for pion
 A men's fragrance from Givenchy
 The symbol for political life used in Boethius' Consolation of Philosophy
Uppercase Π:
 The product symbol
  (Pi function), the Gamma function when offset to coincide with the factorial
 , the reciprocal of the Pi function

Pi as a word
 Pi (instrument)
 Pi (.hack), a fictional character from the multimedia franchise .hack//G.U.
 Pi Magazine
 Pi Recordings, a record label
 "Pi", a song from the Hard 'n Phirm album Horses and Grasses; the song ends at 3:14
 Pi, a member of Team Robo in Sega Soccer Slam
 Pi, a fictional character in the novel Life of Pi
 Pi County, county in Sichuan, China
Psi

Psi could mean:

As a word
 Psi (Cyrillic) (Ѱ, ѱ), a letter of the early Cyrillic alphabet, adopted from Greek
 Psi (Ψ, ψ) a letter of the Greek alphabet
 Psi (comics), a character in DC Comics
 Psi (instant messaging client), a popular Jabber client program
 Psi (parapsychology), psychic or paranormal phenomena

As a Greek letter
 J/ψ particle, a subatomic particle
 Wavefunction in Quantum Mechanics, ψ
 In mathematics, Ψ is used to denote the angle between the tangent and the x-axis in the intrinsic coordinates system
 Again in mathematics, Ψ is also used to denote the Digamma and Polygamma functions.
 In physical chemistry, Ψ represents water potential, the potential energy of a water solution relative to pure water.
 Ψ stands for psychology and psychologist, often used in the logo of various psychological associations -- for example, see IUPsyS.

psi
 Pounds per square inch, a unit of pressure
Storage area network

A Storage area network (SAN) is a computing solution for accessing and storing data. To the user, Storage Area Networks appear to be local to the operating system, but they are actually remote.

To understand the difference between a SAN and Network Attached Storage (NAS), the difference between the file system and storage must be made clear.

The file system is the interface that allows the user to access their data that is stored in physical storage (such as hard disks). From the point of view of the user, their data is saved as files. The file system takes care of storing the file data, which might actually be broken up into pieces and stored in different locations in storage.

On a personal computer, the file system and storage are on the same machine (Direct Attached Storage). In Network Attached Storage, the file system and storage are on a remote server. In a Storage Area Network, the file system is on the local machine, and the storage is on a remote machine.

Computing
Zeta (disambiguation)

Zeta or ZETA can refer to:

Alphabet
 Zeta (letter), the sixth letter of the Greek alphabet.

Science
 Zeta functions, in mathematics
 Riemann zeta function
 Tropical Storm Zeta, formed in December 2005 and lasted through January 2006
 Z-pinch, in fusion power
 Zero Energy Thermonuclear Assembly reactor, a British test facility

Computer 
 magnussoft ZETA, a computer operating system
 Zettabyte File System developed by Sun Microsystems

Geography
 Zeta River, in Montenegro
 Zeta plain, in Montenegro

History
 Principality of Zeta, a medieval state, today Montenegro
 Zeta Banovina, one of provinces (banovina) of the Kingdom of Yugoslavia between 1929 and 1941

Popular culture
 Zeta Metroid, species of Metroid from Metroid II: Return of Samus
 Z (movie), a political movie by Costa Gavras
 Catherine Zeta-Jones, Welsh actress
 Mobile Suit Zeta Gundam, a televised anime

Publishing and Manufacturing
 Zeta (magazine), a Baja California investigative journalism newsweekly
 GM Zeta platform, a full-size car series
 Zeta, an Australian car produced by Lightburn
 A zeta key, a tool used to drive screws and bolts which have a hexagonal socket in the head.
Rings of Saturn

The rings of Saturn are the planetary rings around the planet Saturn, which can be seen with a small telescope. They consist of many small particles, ranging in size from microscopic to the size of a bus (or bigger) that form clumps that move around Saturn. The particles in the rings are made almost entirely of water ice, with just a small amount of dust and other chemicals.  There are some gaps in the rings.  The moon Pan causes the gap called the "Encke gap" in Saturn's A ring. The Cassini Division, discovered by Giovanni Domenico Cassini, is a gap between the A ring and the B ring. It is a product of orbital resonance.

References

Saturn's moons
Network-attached storage

Network attached storage (or NAS) is a computing solution. It means that storage (like a number of hard disks) is put on a computer network, so different users can access it. Today, boxes that already can do this are available rather cheaply. Also, such boxes can be built easily using a small or old computer. NAS is similar to, but easier to set up than a Storage area network.

Computer networking
Chanson

Chanson is the French word for "song".  The word is often used in music to mean any song with French words, but it is more often used when talking about songs in which lyrics have been set to music by French classical composers.

Very often "chansons" refers to the French songs that were sung in the late Middle Ages and Renaissance.  People who sang these chansons were called "chansonniers". They had various forms, including ballade, rondeau and virelai.  Some composers at the time liked to set popular poetry to music.  The earliest chansons were for two, three or four voices, many of them being for three voices.   By the 16th century most were for four voices. Sometimes, the singers were accompanied by instruments.

Early chansons

The first important composer of chansons was the medieval composer Guillaume de Machaut.  In the Renaissance Guillaume Dufay and Gilles Binchois wrote many simple chansons.  Later Johannes Ockeghem and Josquin des Prez composed chansons which had lots of imitation between the voices. Clément Janequin wrote more simple, homophonic chansons.  He worked in the area around Paris.  Later composers such as Orlando de Lassus were influenced by the Italian madrigal. The style of music started to be used in music for instruments.

The first book of sheet music printed from movable type was Harmonice Musices Odhecaton, a collection of 96 chansons by many composers, published in Venice in 1501.

Later chansons

During the 16th century French songs started to be composed with lute or keyboard accompaniment.  In the 19th century many composers wrote songs with piano accompaniment.  These chansons were often called mélodies.

Popular Chanson
In France today "chanson" often refers to the work of more popular singers such as Georges Brassens, Jacques Brel, Édith Piaf, Camille, Olivia Ruiz.
French chansons of Jacques Brel have been translated and are interpreted in English by Arnold Johnston, Professor at West Michigan University. More than 100 chansons of Brel, Brassens, Barbara, Bécaud, Ferrat, Aznavour, Trenet et Ferré have been translated and are interpreted in German language by the Duo Stéphane & Didier (see www.deutsche-chanson-texte.de).

Related pages
 Mélodie

References 

Medieval music
Renaissance music
Song forms
A-type asteroid

A-type asteroids are fairly uncommon closer asteroids that have a strong, broad 1 µm olivine feature and a very reddish spectrum shortwards of 0.7 µm. They are thought to come from the completely differentiated mantle of an asteroid.

A-type asteroids are so rare that as of 2005 only 17 had been found.

Other websites 
 A technical report on A-Type Asteroids
C-type asteroid

C-type asteroids are asteroids made of carbonates. They are the most common variety taking up around 75% of known asteroids, and an even higher percentage in the farther part of the belt beyond 2.7 AU, which is dominated by this asteroid type. The amount of C-types may actually be higher than this, because C-types are much darker than most other asteroid types except D-types and others common only at the extreme farther edge of the Main Belt.

Characteristics
This type of asteroid has very similar spectra to carbonaceous chondrite meteorites (types CI and CM), whose chemical make-up is about the same as the Sun and the primitive solar nebula, except that they do not contain hydrogen, helium and other volatiles. Hydrated (water-containing) minerals are present.

C-type asteroids are very dark with albedos usually in the 0.03 to 0.10 range. Consequently, whereas a number of S-types can normally be viewed with binoculars at opposition, even the biggest C-types require a small telescope. The potentially brightest C-type asteroid is 324 Bamberga, but that object's very high eccentricity means it rarely reaches its maximum magnitude.

Their spectra contain moderately strong ultraviolet absorption at wavelengths below about 0.4 μm to 0.5 μm, while at longer wavelengths they are very featureless but slightly reddish. The so-called "water" absorption feature around 3 μm, which can be a sign of water content in minerals is also present.

The biggest unequivocally C-type asteroid is 10 Hygiea, although the SMASS classification places the biggest asteroid 1 Ceres, here as well, because that scheme lacks a G-type.

References
 S. J. Bus and R. P. Binzel Phase II of the Small Main-belt Asteroid Spectroscopy Survey: A feature-based taxonomy, Icarus, Vol. 158, pp. 146 (2002). 

Asteroids
Marcus Aemilius Lepidus

Marcus Aemilius Lepidus (born 88/89 BC, died 12/13 BC) was a Roman politician. He was one of the closest men to Julius Caesar. He was Caesar's deputy in Rome when Caesar was away from Rome defeating Pompey in the battle of Pharsalus in Greece. He served as Pontifex Maximus (High Priest) after Caesar's death. 

Together with Octavian and Mark Antony he formed the Second Triumvirate to oppose the conspirators. The Triumvirate was set up to sideline the Consuls and Senate, which means it was the effective end of the Roman Republic.

Lepidus was older than the other two triumvirs. After the Battle of Philippi, he governed Spain and part of North Africa. He was blamed for a revolt in Sicily. This gave Octavian the excuse to strip him of his offices, except for Pontifex Maximus. He died peacefully in Circeii in Italy about end 12 to early 13 BC.

80s BC births
10s BC deaths
Roman people
European politicians
Lacrosse

Lacrosse, invented by the Native Americans, is a popular team sport in North America and a national summer sport for Canada. It involves the use of nets, or "heads" as they are called, which consist of a wooden or metal shaft with a net on the end. Hockey is a game based on this sport. 

There are about three different forms of lacrosse based on the different Native American tribes or places of how they played it. One of the ways still played today is called double stick; you play by using a two and a half foot stick in each hand and tossing a deer skin ball in between the two sticks.

The name “lacrosse” was named by the French settlers; with “Crosse” meaning curved stick it is called the curved stick. Lacrosse played a more serious role in Native American culture than anywhere else. It was often used to settle tribal disagreements. Lacrosse was not a very well-known sport until the late nineteenth century.  Now more than half a million people are playing.

How the game is played 

Lacrosse has two teams, each with ten players. There is one goalie(using a head much larger than a normal players), three defensemen(using a stick with a longer shaft), three midfielders and three attack men. The goalies defend the goals, and if the ball goes into the goal, the team who scored the goal gains a point. Whoever scores the most goals by the end of the game wins, with an overtime period being played if the game is tied. The game has four quarters and starts with a "face off" at the beginning of each quarter. A face off is when the ball is on the ground to start the game, and one person from each team fights for possession of the ball ball.

References
"Lacrosse." World Book Advanced. World Book, 2013.
US Lacrosse. Thomas Vennum, Jr., n.d. Web. 6 Dec. 2012. <http://uslacrosse.org/TopNav/MuseumHallofFame/History.aspx >.
Steve Reich

Stephen Michael "Steve" Reich (Born October 3, 1936) is an American composer of music in the style of minimalism. He is known for his music made with tape recordings, and instrumental music with a steady beat (such as Music for 18 Musicians).

He also wrote pieces that used what is called a phasing technique. With phasing technique, two parts might be playing the same part but at slightly different speeds. It is almost like a canon, or round. He wrote pieces like these for piano, violin, and, again, for tape recordings.

He also composed such pieces like In C and Different Trains, some of his most popular works. Others include, Drumming, City Life and The Cave.  

The critic Kyle Gann has said Reich "may...be considered...America's greatest living composer."
 

On January 25, 2007, Reich was named the 2007 recipient of the Polar Music Prize, together with jazz saxophonist Sonny Rollins. On April 20, 2009, Reich was awarded the 2009 Pulitzer Prize for Music for his Double Sextet.

References

Other websites
 (an example of phasing, using two pianos)
 (a composition by Steve Reich for tape)

1936 births
Living people
American composers
Girl group

A girl group is a music group with a group of female singers who normally harmonise together.

The term "girl group" is also used in a narrower sense in English-speaking countries. It suggests the American female pop singing groups of the late 1950s and early 1960s. They were hugely successful for a time, between the decline of early rock and roll and the British Invasion. Many of them were influenced by doo-wop style.

In the 1950s and 60s, the groups were mostly self-organised, girls who knew each other and often grew up together. The Chantels, for example, were four girl choristers from a Catholic high school in the Bronx, 1957. The Ronettes were two sisters and a cousin.p197 The Supremes were girls from a public housing estate in Detroit, Michigan. They were, and still are, America's most successful vocal group of all time. These groups had managers, of course, because they needed someone to deal with the music industry. But the managers did not set up the groups; they came after the groups were formed.

Later, almost all groups were created by public relations professionals to meet a market need. The Spice Girls were a good example of this. They were put together in the mid-1990s by a family management team. Their managers' idea was to create a girl group to compete with popular boy bands that dominated the pop music scene in the mid- to late-1990s. The Spice Girls sold most albums, and had the best-selling album of all time.

One obvious difference between the earlier groups and the later ones was in their social backgrounds. Earlier American groups, having grown up together, were all of the same social origin and colour. What is more, they had usually sung together, and socialised together, before they formed up as a group. This is also true of most of the earlier British boy groups. The later groups, on the other hand, were deliberately chosen for variety. This was done so that all sections of the audience would have at least one member they could identify with. They had not sung together, or maybe met each other, until their PR manager introduced them.

With the changing times, the marketing of popular music changed greatly, so that direct comparison of sales is not simple. but in many parts of the world digital sales are now the most important.

References
Exposure (photography)

In photography, exposure is used to mean two things. Photograhic films or sensors have a certain senitivity. That means that a certain amount of light needs to be able to reach the film or sensor, before the image is correctly exposed. An exposure can also refer to a photo exposed that way.

Photography
Bury (disambiguation)

Bury can mean the following:

Places 
Metropolitan Borough of Bury - A borough in the Metropolitan county of Greater Manchester
Bury - The largest town in the Metropolitan Borough of Bury

Other uses 
Bury or Burial - To put something underneath others, or to put a body in the earth
Metropolitan Borough of Bury

The Metropolitan Borough of Bury is one of the ten Metropolitan boroughs in the metropolitan county of Greater Manchester, England.

It was set up in 1974 from the county borough of Bury and the boroughs of Prestwich and Radcliffe, along with the urban districts of Tottington and Whitefield, and part of the urban district of Ramsbottom.

The metropolitan borough, has an area of .

Twin towns 
 Angoulême
 Tulle, Correze Department.  Originally twinned with Prestwich.
 , Schorndorf, a medieval market town to the east of Stuttgart.
 Woodbury, New Jersey.
 Datong.

References

Other websites 
 Bury MBC website

1974 establishments in England
Bury
Metic

In Ancient Greece, a metic () was a foreigner living in a Greek city-state (polis). The metic did not have the same citizen rights as a citizen who was born in the state he was living in.

The term 'metic' was especially used in ancient Athens in the 4th and 5th centuries BC. A notable metic was Aristotle, who was born in Stageira but lived in Athens for a long time.

Regardless of how many generations of the family had lived in the city, metics did not become citizens unless the city chose to bestow citizenship on them as a gift. This was rarely done. Citizenship at Athens brought eligibility for numerous state payments such as jury and assembly pay, which could be significant to working people. During emergencies the city could distribute rations to citizens. None of these rights were available to metics. They were not permitted to own real estate in Attica, whether farm or house, unless granted a special exemption.

Metics shared the burdens of citizenship without any of its privileges. Like citizens, they had to perform military service and, if rich enough, were subject to special tax contributions. Citizenship was very rarely granted to metics. More common was the special status of "equal rights" (isoteleia) under which they were freed from the usual liabilities.

The system came to an end in Hellenistic Athens, when the purchase of citizenship became very frequent. The census of 317 BC gave 21,000 citizens, 10,000 metics and 400,000 slaves in Attica.

In the Greco-Roman world, free people (non-citizens) living on the territory of a polis were called "paroikoi"  (see etymology of parish), in Asia Minor "katoikoi".

References 

Ancient Greece
Democracy in Athens

Democracy in Ancient Athens was very different from modern democracy.

Citizens
To be classed as a citizen in fifth-century Athens you had to be male, born from two Athenian parents, over eighteen years old, and complete your military service.  Women, slaves, metics and children under the age of 20 were not allowed to become citizens.

Citizens could be involved in the running of Athens and could be chosen for important positions.  They were also allowed to own land.  Citizens were between 10% and 20% of the total population at various times in the 5rh and 4th centuries.

The Ecclesia (Assembly of Men)
Athens had a direct democracy. This meant that each citizen had an equal say and opportunity in the governing of Athens. The citizens of Athens would meet on a hillside (the Pnyx) 30 to 40 times a year to discuss how to run the city better.  Usually a few thousand actually came to the meeting.

All citizens could attend the meetings.  People would stand on a raised platform called the bema to speak.  Speakers wore a garland whilst speaking. Any citizen could speak.

All major decisions concerning the running of Athens were decided here – taxes, war, policy, etc. Any decisions were made by a show of hands.

A black pig would be sacrificed to the gods at the start of the meeting to make sure the meeting went well.

All democratic countries now have an indirect democracy. This means  members of parliament are elected to make decisions concerning government. There are now too many people in different countries for them to meet on a hillside, and many people are too busy to be able to go many times per year.

The Boule (Council of 500)
Cleisthenes, a democratic reformer, divided Attica into ten tribes in 510 BC. The Boule was made up of 50 male Athenian citizens chosen at random from each of the ten tribes (all over 30 years old). This meant that 500 men were elected, but only 50 served at any one time.

References

Ancient Athens
Democracy