On

On, in the Bible. 1 Reubenite conspirator in Korah's revolt. 2 The Egyptian Heliopolis.

Accumulation of cerebrospinal fluid (CSF) in the ventricles (cavities) of the brain. Hydrocephalus is caused by overproduction of CSF, congenital blockage that prevents drainage (see neural tube defect), or complications of head injuries or infections. Normally, CSF circulates through the brain and spinal cord and drains into the circulation. In infants and young children, hydrocephalus causes the brain and skull to enlarge because the fontanels have not yet closed. Without surgery to divert the excess fluid into the blood or abdomen, accumulating fluid eventually compresses the brain, causing convulsions, intellectual disability, and death.

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or job training or occupational training

Vocational instruction for employed persons, first used commonly in the developed world during World War II. Work-related training is necessary as new techniques, new methods, new tools, new synthetic materials, new sources of power, and increased uses of automation continue to bring extensive changes. The UN and its agencies contribute to training programs in developing countries. Seealso technical education.

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officially United Nations Conference on Environment and Development

Conference held in Rio de Janeiro (June 3–14, 1992) to reconcile worldwide economic development with environmental protection. It was the largest gathering of world leaders in history, with 117 heads of state and representatives of 178 countries. Biodiversity, global warming, sustainable development, and preservation of tropical rain forests were among the topics discussed. Five international agreements were signed amid tensions between the industrialized countries of the North and the poorer developing states of the South, who were reluctant to accept environmental restrictions without increased Northern economic aid. Follow-up meetings were held in 1997 at the UN General Assembly in New York and in 2002 in Johannesburg, S.Af. Seealso Rio Treaty.

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Town and unitary authority (pop., 2001: 160,256), geographic and historic county of Essex, southeastern England. It lies on the Thames estuary and the North Sea. The nearest seaside resort to London, it attracts millions of visitors, and there are many resident commuters. It is noted for its 1.3-mi (2.2-km) pier as well as its beaches and gardens; yachting is popular. A 12th-century priory houses a museum.

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(born Aug. 25, 1767, Decize, France—died July 28, 1794, Paris) French Revolutionary leader. In support of the French Revolution, he wrote the radical Esprit de la révolution et de la constitution de France (1791) and was elected to the National Convention in 1792. A close associate of Maximilien Robespierre and a member of the Committee of Public Safety, he was elected president of the Convention in 1793 and sponsored the Ventôse (March) Decrees, which confiscated property of the Revolution's enemies and redistributed it to the poor. He led the victorious attack against the Austrians at Fleurus (in modern Belgium). A fanatical leader of the Reign of Terror, he was arrested in the Thermidorian Reaction and guillotined.

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Series of international meetings of eminent scientists to discuss problems of nuclear weapons and world security. The first meeting was held in 1957 at the estate of Cyrus Eaton in Pugwash, Nova Scotia. The Pugwash organization was established to convene subsequent conferences to discuss arms control and disarmament; these were held in the Soviet Union, Britain, India, and the U.S., among other countries. The organization and its president and founding member, Joseph Rotblat (born 1908), received the 1995 Nobel Prize for Peace.

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biblical On

Ancient holy city, Egypt. The city, which is now mainly ruins lying northeast of Cairo, was the seat of worship of the Egyptian sun god Ra. Its great temple of Ra was second in size only to that of Amon at Thebes, and its priesthood wielded great influence. In the New Kingdom, the temple became the repository of royal records. The city's surviving monument is the obelisk of Sesostris I, the oldest in existence. Two obelisks erected there by Thutmose III and known as Cleopatra's Needles now stand on the Thames River embankment in London and in Central Park, New York City.

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(born Aug. 25, 1767, Decize, France—died July 28, 1794, Paris) French Revolutionary leader. In support of the French Revolution, he wrote the radical Esprit de la révolution et de la constitution de France (1791) and was elected to the National Convention in 1792. A close associate of Maximilien Robespierre and a member of the Committee of Public Safety, he was elected president of the Convention in 1793 and sponsored the Ventôse (March) Decrees, which confiscated property of the Revolution's enemies and redistributed it to the poor. He led the victorious attack against the Austrians at Fleurus (in modern Belgium). A fanatical leader of the Reign of Terror, he was arrested in the Thermidorian Reaction and guillotined.

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(born Nov. 2, 1913, New York, N.Y., U.S.—died Oct. 20, 1994, Century City, Calif.) U.S. film actor. He toured with circuses as an acrobat in the 1930s and served in North Africa and Italy during World War II. He first appeared in movie houses in The Killers (1946), which made him a star. He was noted for his portrayals of physically tough, emotionally sensitive characters. Lancaster's many films include Come Back, Little Sheba (1952), From Here to Eternity (1953), The Rose Tattoo (1955), Sweet Smell of Success (1957), Elmer Gantry (1960, Academy Award), The Birdman of Alcatraz (1962), The Leopard (1963), Atlantic City (1981), Local Hero (1983), and Field of Dreams (1989).

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Set of multilateral trade agreements aimed at the abolition of quotas and the reduction of tariff duties among the signing nations. Originally signed by 23 countries at Geneva in 1947, GATT became the most effective instrument in the massive expansion of world trade in the later 20th century. By 1995, when GATT was replaced by the World Trade Organization (WTO), 125 nations had signed its agreements, which governed 90percnt of world trade. GATT's most important principle was trade without discrimination, in which member nations opened their markets equally to one another. Once a country and its largest trading partners agreed to reduce a tariff, that tariff cut was automatically extended to all GATT members. GATT also established uniform customs regulations and sought to eliminate import quotas. It sponsored many treaties that reduced tariffs, the last of which, signed in Uruguay in 1994, established the WTO.

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(born May 31, 1930, San Francisco, Calif., U.S.) U.S. actor and director. He won attention in the television series Rawhide (1959–66) before his roles in three of Sergio Leone's “spaghetti westerns” (1964–66) made him an international star. He returned to the U.S. for the successful Dirty Harry (1971), the first of a series of action films in which he played laconic and dangerous heroes. He combined directing with acting in films such as Play Misty for Me (1971), Pale Rider (1985), Unforgiven (1992, Academy Award), A Perfect World (1993), The Bridges of Madison County (1995), and Million Dollar Baby (2004, Academy Award). His interest in jazz led him to direct and produce Bird (1988), about Charlie Parker. His minimalist style of acting and direction garnered critical acclaim to accompany his long-established box-office success.

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(born Aug. 21, 1936, Philadelphia, Pa., U.S.—died Oct. 12, 1999, Los Angeles, Calif.) U.S. basketball player, one of the greatest offensive players in basketball history. The 7-ft 1-in. (2.16-m) Chamberlain played two years (1956–58) for the University of Kansas. “Wilt the Stilt” later played centre for the Philadelphia (later Golden State) Warriors (1959–65), the Philadelphia 76ers (1965–68), and the Los Angeles Lakers (1968–73). In the 1961–62 season he became the first player to score more than 4,000 points in regular-season NBA games, including a record 100 points in a single game (1962). He led the NBA in scoring seven consecutive years (1959–65) and in rebounding 11 times. He ranks first in career rebounds (23,924) and career rebounding average (22.9 per game).

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In baseball statistics, on-base percentage (OBP) (sometimes referred to as on-base average [OBA], as the statistic is rarely presented as a true percentage) is a measure of how often a batter reaches base for any reason other than a fielding error, fielder's choice, dropped/uncaught third strike, fielder's obstruction, or catcher's interference (the latter two are ignored as either times-on-base (TOB) or plate appearances in calculating OBP). OBP is added to slugging average to determine on-base plus slugging (OPS). It first became an official MLB statistic in 1984.

Overview

Traditionally, the best leadoff hitters in the game have high on-base percentages. The league average for on-base percentage has varied considerably over time; in the modern era it is around .340, whereas it was typically only .300 in the dead-ball era. On-base percentage can also vary quite considerably from player to player. The record for the highest career OBP by a hitter, based on over 3000 plate appearances, is .482 by Ted Williams. The lowest is by Bill Bergen, who had an OBP of .194.

Though extremely unlikely, it is possible for a player's on-base percentage to be lower than his batting average (H/AB). However very few players in major league history fall into this category, with the majority of them having under 100 ABs, as it requires having almost no walks or times hit by pitch, with a relatively higher number of sacrifice flies (e.g. if a player has 2 hits in 6 at bats with a sacrifice fly, his batting average would be .333, but his on-base percentage would be .286). An example of this phenomenon would be the Hall-of-Fame pitcher Phil Niekro's hitting statistics from 1982. In 87 AB he never walked, but had four sacrifice hits, leading to a Batting Average of .195 and an OBP of .193.

On-base percentage is calculated using this formula:

$OBP\; =\; frac\{H+BB+HBP\}\{AB+BB+HBP+SF\}$

where

• H = Hits
• BB = Bases on Balls (Walks)
• HBP = times Hit By a Pitch
• AB = At bats
• SF = Sacrifice Flies

NOTE: Sacrifice flies were not counted as an official statistic until 1954. Before that time, all sacrifices were counted as sacrifice hits (SH), which included both sacrifice flies and bunts. Bunts (sacrifice hits since 1954), which would lower a batter's on-base percentage, are not included in the calculation for on-base percentage, as bunting is an offensive strategy – often dictated by the manager – the use of which does not necessarily reflect on the batter's ability and should not be used to penalize him. For calculations of OBP before 1954, or where sacrifice flies are not explicitly listed, the number of sacrifice flies should be assumed to be zero.

All-time leaders

#	Player	OBP	Team(s)	Year(s)
1	Ted Williams	.4817	Boston Red Sox	1939–1960
2	Babe Ruth	.4740	Boston Red Sox, New York Yankees, Boston Braves	1914–1935
3	John McGraw	.4657	Baltimore Orioles, St. Louis Cardinals, New York Giants	1891–1906
4	Billy Hamilton	.4552	Kansas City Cowboys, Philadelphia Phillies, Boston Beaneaters	1888–1901
5	Lou Gehrig	.4474	New York Yankees	1923–1939
6	Barry Bonds	.4443	Pittsburgh Pirates, San Francisco Giants	1986–2007
7	Bill Joyce	.4349	Brooklyn Ward's Wonders, Boston Reds, Brooklyn Grooms, Washington Senators, New York Giants	1890–1898
8	Rogers Hornsby	.4337	St. Louis Cardinals, New York Giants, Boston Braves, Chicago Cubs, St. Louis Browns	1915–1937
9	Ty Cobb	.4330	Detroit Tigers, Philadelphia Athletics	1905–1928
10	Todd Helton	.4284	Colorado Rockies	1997–September 28, 2008
11	Jimmie Foxx	.4283	Philadelphia Athletics, Boston Red Sox, Chicago Cubs, Philadelphia Phillies	1905–1942, 1905–1942
12	Tris Speaker	.4280	Boston Red Sox, Cleveland Indians, Washington Senators, Philadelphia Athletics	1907–1928
13	Albert Pujols	.4250	St. Louis Cardinals	2001-September 28, 2008
14	Eddie Collins	.4244	Philadelphia Athletics, Chicago White Sox, Philadelphia Athletics	1906–1930
15	Ferris Fain	.4241	Philadelphia Athletics, Chicago White Sox, Detroit Tigers, Cleveland Indians	1947–1955

bold is active player

Single Season Leaders

#	Player	OBP	Team	Year(s)
1	Barry Bonds	.609	San Francisco Giants	2004
2	Barry Bonds	.582	San Francisco Giants	2002
3	Ted Williams	.551	Boston Red Sox	1941
4	Babe Ruth	.542	New York Yankees	1923
5	Barry Bonds	.529	San Francisco Giants	2003
6	Babe Ruth	.528	New York Yankees	1920
7	Ted Williams	.526	Boston Red Sox	1957
8	Billy Hamilton	.517	Philadelphia Phillies	1894
9	Barry Bonds	.515	San Francisco Giants	2001
10	Ted Williams	.512	Boston Red Sox	1954

See also

• List of MLB players with a .400 on-base percentage
• Moneyball: The Art of Winning an Unfair Game

Notes