Cambridge Encyclopedia Vol. 60

Cambridge Encyclopedia

pontoon - History, Applications

A popular card game which is a variation of blackjack. It can be played by any small number of players, ideally six. The object is to try to obtain a total of 21 with your cards, and is thus also known as vingt-et-un (Fr ‘21’). A pontoon is a flat-bottomed boat or the floats used to support a structure on water. Pontoon boats generally run slower and are less likely to cause h…

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pontoon bridge - Military bridges, Disasters, Notable uses of pontoon bridges

A floating bridge supported by pontoons. The structure may be temporary, as for military usage, or permanent, where deep water and adverse ground conditions make piers expensive. Typically the pontoons consist of flat bottomed boats, hollow metal cylinders, or concrete rafts. Three permanent concrete pontoon bridges cross L Washington in Seattle, USA. Pontoon bridges are floating bridges su…

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Pontus - Geography, Byzantine, Ottoman, and modern history

In antiquity, the territory in NE Asia Minor lying E of Bithynia and S of the Black Sea. In the early 1st-c BC, it was the centre of the empire of Mithridates VI; with his defeat the area became a Roman province. Pontus (Greek Πόντος) is the name which was applied, in ancient times, to extensive tracts of country in the northeast of Anatolia (or 'Asia Minor' , essentially the no…

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Pontus de Tyard

Poet and philosopher, born in Bissy-sur-Fley, Burgundy, EC France. He was a member of the literary circle known as La Pléiade, a forthright theorist, and a popularizer of Renaissance learning for the elite. Associated with the Lyonese poets, especially Maurice Scève, his lyrical works include Erreurs amoureuses (1549), which contain one of the first French sonnet sequences. Important was his pro…

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Pontypridd

51°37N 3°22W, pop (2000e) 32 300. Valley town in Rhondda Cynon Taff, S Wales, UK; on the R Taff, 18 km/11 mi NW of Cardiff; railway; Glamorgan University (1992, formerly Polytechnic of Wales); chemicals, electronics, chains and cables. Pontypridd is a town in the county borough of Rhondda Cynon Taff, South Wales. The name Pontypridd is from the Welsh for bridge by the eart…

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Pony Club - Origins, Structure, National Pony Club Organizations

A worldwide organization with the aim of establishing good horsemanship among children through championships and rallies. It was established in 1929. Pony Club is an international youth organization devoted to the educating youths about horses and horseback riding. Pony Club was formed in Great Britan in 1929 when the Institute of the Horse formed a youth branch of their organiz…

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pony express - History, Trademarks and logos, Statues

A rapid mail service from St Joseph, MO, to San Francisco, CA, using relays of riders and horses. Established in 1860, the service was withdrawn after the completion of the first transcontinental telegraph line a year later. The Pony Express was a fast mail service crossing the North American continent from the Missouri River to the Pacific coast, operating from April 1860 to November 1861.…

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Ponza Islands

Volcanic island group in the Tyrrhenian Sea, off the W coast of SC Italy; main islands are Ponza (the largest), Palmarola, Zannone, Santo Stefano, and Ventotene (formerly Pandateria); islands used in ancient times as places of exile; Agrippina the Elder was banished to Pandateria (AD 29) where she died; political prisoners were detained on Ponza under the fascist regime; regular steamer service co…

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poodle - History, Health concerns, Use, Miscellaneous

A French breed of dog, developed originally for hunting; three sizes: standard (taller than 38 cm/15 in), miniature, and toy (less than 28 cm/11 in); narrow head with pendulous ears; tail docked; thick coat often clipped for ornamental effect. The Poodle is a breed of dog; The breed comes in three sizes (as described by most breed registries): The American Kennel…

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pool

An American table game played in many forms. It uses 16 balls, and a cue similar to that used in billiards and snooker. The most popular form is the variation known as 8-ball pool. The object is to sink all balls of a certain design (usually striped or solid), and then finally the black ball (the No. 8 ball, hence the name). It is played on a table approximately half the size of a standard billiar…

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Poole - Geography, Harbour, History, Culture, recreation, and entertainment, Places of interest, Transport, Schools

50º43N 1º59W, pop (2001e) 138 300. Port town in Dorset, S England, UK; located 6 km/4 mi W of Bournemouth; unitary authority from 1997; birthplace of Thomas Bell and John Le Carré; Poole harbour is Europe's largest natural harbour with cross-channel sailings to France and the Channel Is; ferries to the Isle of Wight and to nearby Brownsea Is, owned by the National Trust and home to the red …

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Pop Art - Origin of the term "pop art", Pop art in Britain, Pop art in America

A modern art form based on the commonplace and ephemeral aspects of 20th-c urban life, such as soup cans, comics, movies, and advertising. Pioneer British Pop artists included Eduardo Paolozzi and Richard Hamilton in the mid-1950s, and leading US contributors in the 1960s include Jasper Johns, Andy Warhol, and Roy Lichtenstein. American Pop is tougher and more deliberately shocking than British, w…

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pop music - History of pop music, Sound and themes

Popular commercial music, with its audience mainly among the young, current since the late 1950s. In c.1900 the name ‘pops’ was given to a series of concerts of light music promoted annually by the Boston Symphony Orchestra. But the singular, pop, refers to the kind of music inaugurated by rock and roll, and which has since diversified to such an extent that it is now most easily defined in term…

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pope - Election, death and abdication, Titles of the Pope, Status and authority, Political role

The title of the Bishop of Rome as head or Supreme Pontiff of the Roman Catholic Church; also, the title given to the head of the Coptic Church. The Bishop of Rome is elected by a conclave of the College of Cardinals, his authority deriving from the belief that he represents Christ in direct descendancy from the Apostle Peter, said to be the first Bishop of Rome. After the decline of the ancient c…

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Pop - Election, death and abdication, Titles of the Pope, Status and authority, Political role

Tewa Pueblo medicine man and revolutionary leader, probably born on the San Juan Pueblo in present-day New Mexico, USA. He first came to the attention of the Spanish when in 1675 he led the resistance against the Spaniard's treatment of Native American medicine men. He then masterminded and led a successful Indian revolt against the Spanish rulers in New Mexico (1680). After many Spanish were kill…

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poplar

A deciduous, N temperate tree; triangular-ovoid to almost heart-shaped leaves; flowers tiny, in pendulous catkins appearing before leaves; seeds with cottony white hairs, which aid wind-dispersal and give rise to the American name cottonwood. Very fast-growing, it is used for cheap timber, matchwood, paper pulp, and as ornamentals. Some species (balsam poplars) have aromatic timber. (Genus: Populu…

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Poppaea Sabina - Life

Roman society beauty and voluptuary who before her marriage to the Emperor Nero (62) had been the wife of his playboy friend, the future Emperor Otho. She shared the then fashionable interest in Judaism, and has been thought by many to have encouraged Nero in his vicious attack on the Christians in the aftermath of the Fire of Rome (64). Poppaea Sabina (c. Poppaea Sabina was the…

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poppy - Symbolism, Gallery

The name given to many members of the family Papaveraceae. All produce latex, are often brightly coloured, and have flowers with two sepals and four overlapping petals, often crumpled when they first open. Red poppies, which grew wild in the fields of Flanders, are used in November as a symbol of remembrance of those who died in the two World Wars. A poppy is any of a number of showy flower…

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Popski's Private Army

A British fighting unit in World War 2. It was raised in October 1942 by Lt-Col Vladimir Peniakoff (1897–1951), known as ‘Popski’, a Belgian of Russian parentage. It had a maximum strength of 195 men, and engaged in intelligence-gathering and hit-and-run attacks behind enemy lines in N Africa and Italy. Popski's Private Army was one of the group of irregular Special Forces units spawned …

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popular culture - Defining popular culture, Popular culture in the 20th and early-21st centuries

A term which, used in a narrow sense, describes mass cultural phenomena, such as soap operas, spectator sports, and pop music; more broadly, it describes the mentality and way of life of most people as opposed to elites. Popular culture is now the subject of serious study, with museums and university courses devoted to it. Popular culture, or pop culture, (literally: "the culture of the peo…

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popular front - Popular fronts in socialist countries, Popular fronts in non-socialist countries

A strategy of the communist movement begun in the 1930s as a means of fostering collaboration among left and centre parties to oppose the rise of right-wing movements and regimes, most obviously fascist ones. There were popular front governments in France, Spain, and Chile. The strategy virtually died with the signing of the Nazi-Soviet Pact (1939), but re-emerged after Hitler invaded the Soviet U…

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population - Population pyramid, Population growth, Population decline, Carrying capacity and population ceiling, Population control, Population transfer

The inhabitants of a region or country who together comprise its native and immigrant people. While it is often used to define the boundary of the citizenry of a sovereign state, it is also used more specifically to refer to a group or category of people sharing specific characteristics, eg ‘the working class population’, ‘the coloured population’, and so on. In biology, plant and anima…

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population biology

The branch of biology dealing with the study of the distributions of populations of living organisms in time and space. It includes the study of the dynamic changes that occur within populations, and the factors that cause those changes. Population biology is a study of biological populations of organisms, especially in terms of biodiversity, evolution, and environmental biology. …

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population density - Biological population densities, Human population density, Other methods of measuring population density

A measure of the number of people living within a standard unit of area, useful for comparative purposes. For example, the population density of The Netherlands (2001) was 38 Population density is a measurement of population per unit area or unit volume. Population density is a common biological measurement and is often used by conservationists as a more appropriate measure than…

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population genetics - Scope and theoretical considerations, Population geneticists

The study of the genetic constitutions of populations acting in consort with the environment, the processes that affect gene and genotype frequencies, and the mathematical theorems that describe them. The basic theorems were established in the period 1908–30, with the work of British geneticists R A Fisher (1890–1962), J B S Haldane (1892–1964), and US geneticist Sewall Wright (1889–1988). In …

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populism - Populist methods, History, Current or recent populists

Essentially a political outlook or mentality rather than an ideology, identified by a popular reaction to dramatic change, such as rapid industrialization. People feel that events are beyond their control, which is blamed on some conspiracy of foreigners, ethnic groups, economic interests, or intellectuals. The populist reaction is to ‘regain’ control from the suggested centres of power, usually…

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porcelain - Scope, materials and methods, Categories of porcelain, History

A hard, vitreous, translucent, resonant material, contrasting with opaque, more porous pottery. It contains china clay (kaolin) and chinastone (petuntse), and is fired at a temperature of c.1200–1350°C, whereas pottery does not contain chinastone, and is fired at a lower temperature. Porcelain was first manufactured by the Chinese in the Tang dynasty (7th–10th-c), when production of the famous …

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porcupine

A cavy-like rodent; some hairs modified as long sharp spines; lives in diverse habitats; 22 species in two families: ground-dwelling family Hystricidae (Old World porcupines) from Africa and S Asia, and tree-climbing family Erithizontidae (New World porcupines), widespread in the New World. This article is about the rodent mammal. For other uses of the term "porcupine" see Porcupine (disamb…

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pornography - Terminology, Technology, History, Legal status, Anti-pornography movement, U.S. Government Commissions, Stereotypes

The presentation of erotic behaviour intended to cause sexual arousal, typically using film, graphic, or written media. It is widely considered to be a demeaning representation of sexuality and the body. Most authorities distinguish between ‘soft’ and illegal ‘hard core’ pornography, but many, especially feminists, argue that the ‘softer’ version should be banned as well. In the US, pornogra…

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porosity - Porosity in earth sciences and construction, Porosity in manufacturing, Measuring porosity

A mechanical property of solids, a measure of their ability to allow the passage of a fluid. The narrow channels that make a material porous allow it to absorb fluid via capillarity, as a sponge absorbs water. Oil exists underground in porous rock; water drains through sand. The term "porosity" is used in multiple fields including manufacturing, earth sciences and construction. …

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porphyria - Signs and symptoms, Diagnosis, Treatment, Culture and history

A group of inherited disorders involving the excess production of chemical substances known as porphyrins. They cause a wide range of abnormalities, including sensitivity of the skin to sunlight, pigmentation of the skin, abdominal pain, and mental confusion. It entered the British royal family through Mary, Queen of Scots, and symptoms were displayed by the Stuarts. It then passed to the Hanoveri…

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port - Major ports

A sweet, fortified wine, first produced in the upper Douro valley, N Portugal. Grapes have been grown on the steeply-terraced hillsides since the 17th-c. The wine used to be transported down the fast-flowing river to Oporto (hence the name), but is today taken by road. ‘Vintage’ port is unblended. All port is aged in pipes (115-gallon wooden barrels). The terms "port" and "seaport" are us…

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Port Harcourt

4°43N 7°05E, pop (2000e) 452 000. Seaport capital of Rivers state, S Nigeria; on R Bonny, 65 km/40 mi from the sea; Nigeria's second largest port; established in 1912; airport; railway link to the Enugu coalfields; university (1975); metals, glass, liquid propane gas, oil refining, petrochemicals, fishing. Port Harcourt is a city located in the Niger Delta in Nigeria. Port…

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Port Louis - History, Geography, Sights, Economy, Demographics

20°18S 57°31E, pop (2000e) 159 000. Seaport capital of Mauritius; established, 1735; trade developed until the building of the Suez Canal; handles almost all of the trade of Mauritius; sugar, textiles, clothes, diamond cutting, watches, electrical and electronic equipment, sunglasses; university (1965); two cathedrals. Port Louis (pronounced locally as paw-louee) is the capital …

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Port Moresby - History, Regions and Suburbs, Transport, Twin towns

9°30S 147°07E, pop (2000e) 240 000. Seaport capital of Papua New Guinea, on the S coast of New Guinea; Allied base in World War 2; airport; university (1965); base for overseas telecommunications and national broadcasting; light industry; Hiri Moale Festival (Aug–Sep), arts festival (Sep). Port Moresby, (9°30′S 147°12′E), population 255,000 (2000), is the capital of Papua New Gui…

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Port of Spain - History, Geography, Governance, Economy, Demographics, Culture and entertainment, Infrastructure, Sister cities

10°38N 61°31W, pop (2000e) 50 000. Seaport capital of Trinidad and Tobago, NW coast of Trinidad; capital of Trinidad, 1783; airport; principal commercial centre in the E Caribbean; oil products, rum, sugar; botanical gardens, two cathedrals, San Andres Fort (1785). Port of Spain, with a municipal population of 49,031 (2000 census) and a metropolitan population estimated at 269,923 resid…

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Port Royal - Colonization of Port Royal, Piracy in Port Royal, Earthquake of 1692 and its aftermath, Miscellaneous

A French religious and intellectual community occupying the former convent of Port-Royal-des-Champs, near Paris. It was associated with the Jansenist movement, and founded by the Abbé de Saint-Cyran (1637), a friend and admirer of the theologian, Cornelius Jansen, himself a devotee of Augustinian philosophy. The community was dispersed in 1665, and the convent destroyed (1710–11). An eart…

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Port Said

31°17N 32°18E, pop (2000e) 551 500. Seaport capital of Port Said governorate, NE Egypt; on Mediterranean coast at N end of Suez Canal, 169 km/105 mi NE of Cairo; founded in 1859 at beginning of Canal construction; shipping services, trade in rice, cotton, salt. Port Said (31.15°?N 32.18°?E)(Arabic بور سعيد, transliterated Būr Saʻīd) is a northeastern Egyptian city near the…

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Port Sudan - History, Tourism, Economy, Geography, Demographics, Transportation

19°38N 37°07E, pop (2000e) 319 000. Seaport capital of Eastern region, Sudan, on the Red Sea coast; Sudan's main port; founded, 1906; airfield; railway; NE terminus of an oil pipeline from Khartoum; handles most of the country's trade. It was founded by the British in 1905 as the terminus of a rail line linking the Red Sea to the River Nile. Port Sudan is known among tourist…

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Port-au-Prince - History, Economy, Transportation, Demographics, Education, Culture, Tourism

18°33N 72°20W, pop (2000e) 859 000. Seaport capital of Haiti; on the Gulf of Gonâve, W coast of Hispaniola I; commercial and processing centre at W end of the fertile Plaine du Cul-de-Sac; airport; archbishopric; university (1944); coffee, sugar; 18th-c cathedral. Port-au-Prince, (Pòtoprens in Kréyòl), population 1,277,000 (2006), is the capital and largest city of Haiti. Growth, es…

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Portadown - History, People, Education, Sport

54º26N 6º27W, pop (2001e) 21 800. Town in Craigavon district, Co Armagh, SC Northern Ireland; on the R Bann, S of Lough Neagh; 40 km/25 mi SW of Belfast; birthplace of Paul Muldoon; railway; linen, engineering, food processing, rose growing. Portadown (Irish: Port an Dúnáin, "port of the fortress") is a town in County Armagh, Northern Ireland. Portadown is situated on the River Bann…

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Portland (Maine) - General, Cities and towns (by country), Buildings, Computing, Passenger trains, Ships, Sports teams, Art

43°39N 70°16W, pop (2000e) 64 200. Business capital and chief port of Maine, USA; seat of Cumberland Co; on the coast of Casco Bay, SE of Sebago Lake; established, 1632; city status, 1832; state capital, 1820–32; railway; Westbrook Junior College (1831); fisheries, ship repair, paper, chemicals, oil trade; birthplace of Longfellow. In Australia: In Canada: In Ho…

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Portland (Oregon) - General, Cities and towns (by country), Buildings, Computing, Passenger trains, Ships, Sports teams, Art

45°32N 122°37W, pop (2000e) 529 100. Freshwater port and capital of Multnomah Co, NW Oregon, USA, on the Willamette R; largest city in the state; laid out, 1845; served as a supply point in the 1850s during the California gold rush and later (1897–1900) during the Alaska gold rush; airport; railway; university (1901); machinery, electrical equipment, food processing, wood products, metal good…

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Portlaoighise

53°02N 7°17W, pop (2000e) 8500. Capital of Laoighis county, Leinster, Ireland; SW of Dublin; railway; jail; small industrial estate. The town was first established by Queen Mary in 1556 as "the Fort of Maryborough" and was renamed 1922 to "Portlaoise". Very few signs of the old garrison remain in the town. The town is a major commercial, retail, and arts centre for the midlan…

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Porton Down - History, Use of Animals, Defence CBRN Centre

A research centre established by the Ministry of Defence in Wiltshire, S England, UK, for the investigation of biological and chemical warfare. Defence Science and Technology Laboratory, Porton Down, or often known more simply as Porton Down, is a United Kingdom government facility for military research, including CBRN defence. Porton Down was set up to provide a proper sc…

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Portree

57°24N 6°12W, pop (2000e) 1970. Port in Highland, NW Scotland, UK; on Loch Portree, E coast; largest town on Skye. Portree (Gaelic Port Rìgh, the King's port) is the largest town on Skye in the Scottish Inner Hebrides. …

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Portrush - Places of interest, History, 2001 Census, People

55°12N 6°40W, pop (2000e) 5800. Town in Coleraine district, Antrim, NE Northern Ireland, UK, on the N coast; railway; engineering; tourist centre for the Giant's Causeway, 11 km/7 mi NE. Portrush (in Irish: Port Rois, ie port of the promontory) is a town in County Antrim, Northern Ireland. In the off-season, Portrush is a dormitory town for the nearby campus of the University of …

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Portsmouth (New Hampshire) - History, Economy, Geography, Education, Government, Shopping, Sport, Tourist Attractions, Places of worship, Future developments, Town twinning

43º05N 70º45W, pop (2000e) 20 800. Seaport and resort town in Rockingham Co, New Hampshire, USA; on Atlantic coast at head of the R Piscataqua that divides New Hampshire and Maine; 70 km/43 mi ENE of Manchester; settled, 1623; city status, 1849; John Paul Jones' ship The Ranger built here (18th-c); treaty ending the Russo-Japanese War signed here (1905); birthplace of Thomas Bailey Aldrich a…

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Portsmouth (Ohio) - History, Economy, Geography, Education, Government, Shopping, Sport, Tourist Attractions, Places of worship, Future developments, Town twinning

38º44N 83º00W, pop (2001e) 20 900. County seat of Scioto Co, S Ohio, USA; on the Ohio R where it meets the R Scioto; railway; birthplace of Kathleen Battle; prehistoric Indian mounds and earthworks. Portsmouth is a city of about 189,000 people located in the county of Hampshire on the southern coast of England. Portsmouth has declined as a military port in recent years but r…

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Portsmouth (UK) - History, Economy, Geography, Education, Government, Shopping, Sport, Tourist Attractions, Places of worship, Future developments, Town twinning

50°48N 1°05W, pop (2001e) 186 700. Seaport city and (from 1997) unitary authority in Hampshire, S England, UK; on Portsea I, 133 km/83 mi SW of London; major naval base; railway; Portsmouth University (1992, formerly Polytechnic); ship repairing, electronics, engineering; ferries to the Channel Is, France, and the I of Wight; birthplace of Charles Dickens; Nelson's flagship HMS Victory; Tudo…

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Portsmouth (Virginia) - History, Economy, Geography, Education, Government, Shopping, Sport, Tourist Attractions, Places of worship, Future developments, Town twinning

36°50N 76°18W, pop (2000e) 100 600. Port and independent city, SE Virginia, USA, on the Elizabeth R; founded, 1752; a base for British and then Revolutionary troops during the War of Independence; evacuated and burned by Union troops during the Civil War (1861), then retaken (1862); part of a US naval complex; railway; shipbuilding (the Chesapeake and the ironclad Merrimack were built here), r…

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Portugal - History, Government and Politics, Foreign Relations and Military, Administrative Divisions, Geography and Climate, Economy

Official name Republic of Portugal, Port República Portuguesa, ancient Lusitania Coordinates: 38°42′N 9°11′W Portugal, officially the Portuguese Republic (Portuguese: República Portuguesa; The territory which forms the modern Portuguese Republic has witnessed a constant flow of civilizations during the past 3,100 years, since the earlier pre-Roman inhabitants, to the Rom…

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Porvoo - Villages

60°24N 25°40E, pop (2000e) 20 900. Picturesque town in Uudenmaa province, SE Finland; near mouth of Porvoonjoki (river); second oldest town in Finland, established, 1346; bishopric; boat service to Helsinki; publishing, brewing, tourism; home of national poet, Johan Runeberg; cathedral (15th-c); cycle race and Porvoo day (Jun); Postmaki Festival (Jul). Porvoo (IPA: [ˈporʋoː]) in Finn…

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Poseidon - Prehistory, Myth, Spoken-word myths - audio files

In Greek mythology, the brother of Zeus, god of water and the sea, depicted with a trident in his hand. He is a violent god, responsible for earthquakes and similar destructive forces. He is also connected with horse-taming. In Greek mythology, Poseidon (Greek: Ποσειδών) was the god of the sea, as well as horses and, as "Earth-Shaker", of earthquakes. In Mycenean culture…

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positivism

In philosophy, the position that all genuine knowledge is derived from and validated by science. Developed from the British empiricist tradition, it was first explicitly formulated in the 19th-c by Comte, and was taken up by the utilitarians (Bentham and Mill), Herbert Spencer, Mach, and others, who were optimistic about the benefits of scientific progress for humanity and who were hostile to theo…

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positron - The positron in fiction

The antiparticle partner to the electron; symbol e+; mass and spin same as electron, but charge +1; discovered in 1932 by US physicist Carl Anderson and British physicist Patrick Blackett (1897–1974), by observing tracks left in cloud chambers by cosmic rays. It annihilates with electrons to give gamma rays, and is emitted by some radioactive sources, such as sodium-22. It is used in positron emi…

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possession - Control, Intention to possess, Importance of possession, Obtaining possession, In radical political philosophy

The alleged control of a living person by an entity lacking a physical body. In the Middle Ages, the Christian Church generally saw possession in terms of demonic control, while in other cultures, shamans who appear to be taken over by a different personality may be thought of as being controlled by (often benign) spirits. These days, cases of apparent possession are frequently interpreted as bein…

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possum

An Australian marsupial of family Burramyidae (pygmy possum, 7 species), family Pseudocheiridae (ringtail possum, 16 species), family Phalangeridae (scaly-tailed possum plus 3 species of brushtail possum), or family Petauridae (Leadbetter's possum plus 2 species of striped possum). A possum is any of about 63 small to medium-sized arboreal marsupial species native to Australia, New Guinea a…

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post-industrial society

An economically and technologically advanced society no longer dependent for its productivity on large-scale, labour-intensive industrial manufacture. The term was coined by the US sociologist Daniel Bell (1919– ) in 1973. A post-industrial society is a proposed name for an economy that has undergone a specific series of changes in structure after a process of industrialization. …

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post-production - Major post-production companies include, Reference

The completion stages of a film after shooting up to the first public showing. The picture is finally edited to the director's satisfaction, and the original negative cut to conform; music and sound effects are recorded and mixed with the actors' dialogue in dubbing the final track. This magnetic record is transferred to a photographic sound negative for printing along with the cut picture negativ…

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post-traumatic stress disorder - Background, Diagnostic criteria, Symptoms and their possible explanations, Biology of PTSD, Prevalence, Veterans and PTSD politics

A severe anxiety reaction that occurs in some people exposed to a traumatic event involving witness to, threat of, or experience of death or serious harm; it often affects war veterans. The traumatic event is re-experienced in the form of images or thoughts (‘flashbacks’), accompanied by sweating, a rapid heart beat, and a feeling of fear. Flashbacks are often precipitated by cues that resemble …

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postage stamp - History, Dispensing, Types of stamps, First day covers, Souvenir sheets, Cinderellas, Collecting, Famous stamps

An adhesive printed or embossed stamp or label indicating the prepayment of a fee for the conveyance of letters, postcards, parcels etc. The first postage stamps were issued in England in the 1840s, but soon became a global phenomenon. Definitive stamps are those which are normally available for purchase, while commemorative stamps are issued periodically to mark special occasions. The latter in p…

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poster art - Notable poster artists

The development of posters as an art form, dating from the late 19th-c, when there were improvements in printing techniques, especially colour lithography. Toulouse-Lautrec was an early master who achieved some of his most striking effects through this medium; and the work of Czech artist Alphonse Mucha (1860–1939) has enjoyed a wide revival. In France, posters became a work of art that tr…

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Postmodernism - Overview, Term, Development of postmodernism, Deconstruction, Social construction, structuralism, post-structuralism, Criticism

A term used in architecture to describe a style or concept that supersedes 20th-c Modernism and the International Style in particular. Often used in a polemical and self-consciously intellectual way, it is generally applied to buildings which draw upon an eclectic range of stylistic precedents, especially classical, such as the A T & T building, New York (1978–83), architects Johnson & Burgee. In…

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PostScript - Email era, Common postscript examples

A computer language which has been developed to provide a uniform means of describing pages of text and/or graphics. It is widely used in desk-top publishing. PostScript-compatible printers contain a microcomputer system called a raster image processor (RIP) which can interpret a PostScript program and produce the relevant printed page(s). A postscript (from post scriptum, a Latin expressio…

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Potala Palace - White Palace, Red Palace

An imposing 13-storey stronghold constructed on a rocky outcrop near Lhasa, Tibet, in the 17th-c. Once the religious and political centre of Tibet, the complex includes the Red Palace (former seat of the Dalai Lamas) as well as many halls, chapels, and prisons. A world heritage site. The Potala Palace (Tibetan: པོ་ཏ་ལ;?Wylie: Po ta la, Traditional Chinese: 布達拉宮, Simplifi…

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potash - Potash production and trade

Potassium oxide, K2O. The term is generally used for any potassium compounds used as fertilizers whose potassium content is reported in terms of the equivalent amount of K2O, or about 1·2 times the percentage by weight of potassium. Potash (or carbonate of potash) is an impure form of potassium carbonate (K2CO3) mixed with other potassium salts. The term has become somewhat amb…

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potassium - Isotopes, Potassium in nutrition and medicine

K (Lat kalium), element 19, melting point 63°C. One of the most reactive metals, and the third of the alkali metal group. It is not found free in nature, but obtained chiefly from mineral deposits of the chloride (KCl) and the nitrate (KNO3, also known as nitre or saltpetre). The metal is prepared by the electrolysis of molten KCl or KOH. It is an important strong reducing agent, and must be kept…

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potato - Toxic compounds in potatoes, Cultivation, New potatoes, References and external links

A well-known tuber-producing plant and staple crop throughout temperate regions of the world; an erect to somewhat sprawling perennial; pinnate leaves; clusters of drooping, white or purple flowers, with a 5-lobed corolla and five yellow stamens forming a prominent cone. The fruit is a berry similar in appearance to that of the tomato (a relative), but usually greenish, and unlike the tomato it is…

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potential

A scalar quantity associated with a force whose rate of change with distance is proportional to the strength of that force; symbol V. In a gravitational field, it is the potential energy of an object of mass 1 kg; in an electric field it is the potential energy of a charge of 1 C. In physics, a potential may refer to the scalar potential or to the vector potential. Leading examples are th…

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potential difference - Explanation

A quantity in physics, often called voltage; symbol U, units V (volt). A potential difference is said to exist between two points if work must be done against an electric field to carry a charge from one point to the other. A potential difference divided by the distance between the two points gives the strength of the electric field between the points. The potential difference between the terminal…

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potential energy - Gravitational potential energy

The energy stored by an object by virtue of its position in the region of influence of some force; symbol V, units J (joule). For example, an object acquires potential energy equal to the work done against the force of gravity in raising it above the Earth's surface; when released, the object falls to the ground, and its potential energy is converted into kinetic energy, the energy of motion. Work…

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potentilla

A member of a large genus of annuals or perennials, sometimes creeping, rarely small shrubs, native to N temperate regions; leaves with three leaflets, or pinnately or palmately divided into leaflets; flowers with epicalyx, 4–5 sepals, 4–5 petals;. They can be roughly divided into two groups: cinquefoils with 5-petalled flowers, and tormentils with 4-petalled flowers. Several, especially the shr…

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potentiometer - Potentiometer as measuring instrument, Potentiometer as electronic component, Theory of operation, Early patents

An instrument for the accurate measurement or control of electrical potential. A known potential drop is created in a long (usually coiled) wire by a battery, and a sliding contact is used to tap off any proportion of this drop. Potentiometers are used in electronic circuits, especially as volume controls in transistor radios. The original meaning of the term potentiometer, which is still i…

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potlatch - Overview, Traditional historical, "Potlatch" and "potluck", Sources, Further reading (Tlingit)

A feast celebrating an important event, or following personal humiliation, at which the host gives away his wealth (slaves, blankets, canoes, etc). People receiving wealth in this way would later give their own potlatches, ensuring circulation of some of the property. It was a common practice among North American Indians of the Northwest Pacific coast, becoming increasingly competitive under press…

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Potomac River

River in West Virginia, Virginia, and Maryland, USA; formed at the junction of two branches rising in the Allegheny Mts; flows through Washington, DC, into Chesapeake Bay; length 460 km/286 mi; navigable for large craft as far as Washington; main tributary the Shenandoah; the Great Falls lie 24 km/15 mi above Washington. …

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Potos

19°34S 65°45W, pop (2000e) 136 400. Capital of Potosí department, SW Bolivia; altitude 4070 m/13 353 ft; highest city of its size in the world; founded by Spanish in 1545; major silver-mining town in 17th–18th-c, becoming the most important city in South America at the time; airfield; railway; university (1892); tin, silver, copper, lead; chief industrial centre of Bolivia; Convent of San…

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Potsdam - History, Politics, Sister cities, Education and research, Sights in Potsdam

52°23N 13°04E, pop (2000e) 145 000. Capital of Potsdam county, E Germany; on R Havel, W of Berlin; former residence of German emperors and Prussian kings; badly bombed in World War 2; scene of the 1945 Potsdam Conference; railway; Academy of Political Science and Law; colleges of cinematographic and television art; Central Meteorological Centre; food processing, pharmaceuticals, electrical equ…

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Potsdam Conference - Primary results of the conference, The Potsdam Conference was preceded by

A conference which met during the final stages of World War 2 (17 Jul–2 Aug 1945). Churchill (and later Attlee), Stalin, and Truman met to discuss the post-war settlement in Europe. Soviet power in E Europe was recognized, and it was agreed that Poland's W frontier should run along the Oder–Neisse line. The decision was made to divide Germany into four occupation zones and to transfer the German…

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Potter Palmer

Merchant and real-estate entrepreneur, born in Albany Co, New York, USA. He had his own dry goods stores in upstate New York before he moved to Chicago (1852) and opened one there. His innovative practices, such as allowing customer returns and advertising and displaying merchandise, became known as the Palmer system and led to great success. Overworked and ailing, in 1867 he turned the store over…

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Potter Stewart - Education, Life experience, Supreme Court service

Judge, born in Jackson, Michigan, USA. He was in private practice and involved in Cincinnati politics when he was appointed to the US Court of Appeals (1954–8). President Eisenhower named him to the US Supreme Court (1959–81), where he took independent and moderate judicial positions. Potter Stewart (January 23, 1915 – December 7, 1985) was an Associate Justice of the United States Supr…

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potter wasp

A solitary, hunting wasp; adults make flask-shaped nests of clay and saliva; females provision nests with paralysed caterpillars or other insect larvae before egg laid; adults feed on nectar. (Order: Hymenoptera. Family: Eumenidae.) Potter wasps (or mason wasps) also known as Dirt daubers are cosmopolitan wasps that are typically treated as a subfamily of Vespidae, but have in the past some…

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pottery - Techniques, Production stages, History

Vessels made out of fired clay, produced by mankind since the earliest civilizations. They can be hand-built, moulded, or in more sophisticated societies thrown on a wheel. Pottery tends to be soft and rather porous, and is therefore normally protected by a glaze, which also gives a shiny decorative appearance. Glaze is applied after the first firing, when the pot is placed in the kiln for the sec…

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pouched rat

A type of rat native to Africa; three species resemble rats, two resemble hamsters; all have internal cheek pouches; rat-like species often have blind wingless earwigs (of genus Hemimerus) in their fur. (Subfamily: Cricetomyinae, 5 species.) Pouched rats are a group of African rodents in the subfamily Cricetomyinae. …

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pound (economics)

The unit of currency of the UK (the pound sterling), and certain other countries. The £ symbol is derived from letter L for libra, a measure of weight. It was formerly divided into 20 shillings and 240 pence; but since decimalization in 1971 it is divided into 100 pence (new pence). One-pound gold coins called sovereigns were made for circulation in Britain from 1489 to 1931, after which paper po…

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powder metallurgy - History and capabilities, Powder Production Techniques, Powder pressing, Continuous powder processing, Special products

Making metal shapes by compressing powdered metal into a finished or near-finished shape. First used for tungsten lamp filaments, it is now used for such products as tungsten carbide cutting tools and self-lubricating bearings. It can be used on iron, tin, nickel, copper, aluminium, and titanium. The powders are made a specific and regular size by atomization (cooling a spray of molten metal) or c…

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Powell Clayton

US senator and governor, born in Bethel Co, Pennsylvania, USA. A civil engineer, he enlisted in Kansas regiments during the Civil War (1861–5), buying a plantation in Arkansas afterwards. As Arkansas governor (Republican, 1868–71), he attacked the Ku Klux Klan and issued $6 900 000 in bonds for railroad construction. Indicted for corruption, but never convicted, he served in the US Senate (Rep…

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power (physics) - Mechanical power, Electrical power, Power in optics

The rate of change of work with time; symbol P, units W (watt). To lift an object some distance into the air requires a fixed amount of work, but to do the job more quickly requires more power. where When the rate of energy transfer or work is constant, all of this can be simplified to where In mechanics, the work done on an object is related to the force…

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Powhatan - History, Characteristics, Powhatan today, Powhatan in film

Pamunkey Powhatan chief, born near present-day Richmond, Virginia, USA. He inherited the chieftainship of the so-called Powhatan Confederacy from his father, but he greatly extended his ‘empire’ until, by the arrival of the English (1607), it was an alliance of roughly 30 tribes, over 100 villages, or 9000 people. The first Native American leader known to have contact with English settlers in No…

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Powys - Places of interest

pop (2001e) 126 300; area 5077 km²/1960 sq mi. Mountainous county in E Wales, UK; created in 1974, and status reaffirmed in 1996; bounded E by England; drained by the Usk, Wye, Taff and Tawe Rivers; Lake Vyrnwy (reservoir) source of water for Liverpool and Birmingham; administrative centre, Llandrindod Wells; other chief towns, Brecon, Newtown, Welshpool; agriculture, forestry, tourism; Brec…

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Pozna?

52°25N 16°93E, pop (2000e) 595 000. Capital of Pozna? voivodship, W Poland, on R Warta; capital of Poland until 13th-c; bishopric; airfield; railway; two universities (1918, 1919); metallurgy, machinery, chemicals, clothing, food processing, transport; noted for its choirs and the Polish Theatre of Dance; Franciscan church (17th–18th-c), 13th-c castle with museum of crafts, national museum, G…

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Praetorian Guard - Relationships between emperors and their Guard, Organization and conditions of service

An elite corps in imperial Rome - effectively, the emperor's bodyguard. Their real influence dates from the 20s AD, when they were concentrated in a single barracks in Rome itself, and put under the control of a single commander. The Praetorian Guard (in Latin: praetoriani) comprised a special force of bodyguards used by Roman Emperors. Although the Praetorians have similarities…

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Pragmatic Sanction

A Habsburg family law devised in 1713 by Charles VI which established the indivisibility of the Habsburg estates and secured the succession through the female line in case of no male heir. Later, much effort was deployed in achieving internal and international guarantees for his daughter Maria Theresa's claims, though these were repudiated by Frederick II of Prussia (1740). …

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pragmatics - Topics in pragmatics, Bibliography

In linguistics, the study of the way context influences the use and understanding of language, particularly in interactive situations such as addressing, replying, being polite, joking, or being persuasive. This includes the study of speech acts - the way language is used to do things; for example, I promise, used in appropriate circumstances, is to promise. In linguistics and semiotics, pr…

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pragmatism - Themes, Variations, Contemporary echoes, Notable pragmatists

A philosophical theory of truth and meaning developed by the American philosophers Peirce, William James, and Dewey. Essentially, it is the view that theoretical disputes can be resolved by examining their practical consequences: beliefs are true if and because they work not vice versa. Pragmatism, as a school of philosophy, is a collection of many different ways of thinking. So…

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Prague - History, Sights, Culture, Economy, Colleges and universities, Transport, Sport, Miscellaneous, Prague as a venue

50°05N 14°25E, pop (2000e) 1 219 000. Industrial and commercial capital of Czech Republic, on R Vltava; important trading centre since 10th-c; capital of newly-created Czechoslovakia, 1918; occupied by Warsaw Pact troops, 1968; historical centre declared a conservation area, 1971; archbishopric; airport (Ruzyn?); railway; metro; Charles University (1348); technical university (1707); chemical…

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Praia

14°53N 23°30W, pop (2000e) 43 000. Port and capital of the Republic of Cape Verde, on S shore of São Tiago I; airport connecting with Dakar and neighbouring islands; naval shipyard, light industry, fishing, commerce. …

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prairie

The extensive grassland and treeless region of N USA and Canada. Originally the vegetation was coarse grass and habitat for the bison. Its fertile soils encouraged ploughing and cultivation, and the prairies are now a major arable area. Cattle ranching is also important. Little natural prairie survives. Prairies are known as steppe in Europe and Asia, and as pampa(s) in South America. Prair…

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prairie dog - Etymology, Biology and behavior, In captivity, Classification and first identification

A North American squirrel; length, up to 45 cm/18 in, with short tail; inhabits open country; digs extensive burrow systems called ‘towns’ (composed of ‘wards’ which contain social units called ‘coteries’); (Genus: Cynomys, 5 species.) In 1900, a ‘town’ was discovered that measured 100 mi by 250 mi, housing 400 million dogs. The prairie dog (Cynomys) is a small, burrowing rodent n…

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pratincole

A bird of the Old World family Glareolidae, subfamily Glareolinae (8 species); long wings, short tail; short black bill with reddish base; short legs (Genus: Glareolus, 7 species) or long legs (Genus: Stiltia); lives near water; eats insects. …

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prawn

A general name for many shrimp-like crustaceans. Prawn and shrimp are interchangeable common names, with usage varying according to local tradition; in the USA, for example, shrimp is the more commonly used term. (Class: Malacostraca. Order: Decapoda.) Prawns are edible, shrimp-like crustaceans, belonging to the sub-order Dendrobranchiata?. …

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Praxiteles

Sculptor from Athens, considered one of the greatest of Greek sculptors. His works have almost all perished, though his ‘Hermes Carrying the Boy Dionysus’ was found at Olympia in 1877. Several of his statues are known from Roman copies. Praxiteles (IPA: [prækˈsɪtlˌiz]) of Athens, the son of Cephisodotus, was the greatest of the Attic sculptors of the 4th century BC, who has left an im…

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prayer - Forms of prayer, The act of prayer, Prayer in Western religions, Prayer in Eastern religions

Turning to God in speech or silent concentration. A major characteristic of most religions, it includes petition, adoration, confession, invocation, thanksgiving, and intercession. It can be silent (mental) or vocal, public or private, individual or corporate, liturgical or free. It is generally considered an essential feature of worship. Prayer is an active effort to communicate with a dei…

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praying mantis - Body, Camouflage, Senses, Flight, Habitat, Diet, Predators, Endangered Status, Pest Control, Lifespan, Species

A large, green mantis which lies motionless in wait for its prey, holding its grasping forelegs in an attitude suggestive of prayer; found in Europe. (Order: Mantodea. Family: Mantidae.) A praying mantis, or praying mantid, is the common colloquial name for an insect of the order Mantodea. Like all insects, the body of a praying mantis can be broken down into a head a top the bo…

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pre-eclampsia - Diagnosis, Appearance, Causes, Pathogenesis, Therapy

A potentially serious, abnormal condition of late pregnancy, with high blood pressure, protein in the urine, and swelling (oedema) of the limbs; also known as pregnancy induced hypertension. It is an uncommon condition, and the cause is unknown, but it is more common in multiple pregnancies and in women under 16 and over 40 years of age. Blood pressure is monitored regularly during pregnancy to ch…

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Pre-Raphaelite Brotherhood (PRB) - Beginnings of the Brotherhood, Early doctrines, Public controversies, Later developments and influence, List of artists, Collections

A group of artists formed in London in 1848 with the aim of revolutionizing early Victorian art; their preference for the styles of the 15th-c (ie pre-Raphael) led to someone (it is unclear who) suggesting the name c.1847. Leading members were Millais, Hunt, and D G Rossetti. They rejected the sentimental mediaevalism and academic formulae of the time, seeking instead a new truth to nature and fre…

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precedent - Mandatory and persuasive precedent, Custom and case law, Actual court formulations of the doctrine

A doctrine of law, present in most legal systems, whereby an earlier court's decision or judgment on the same point of law involving similar facts is followed by another court at a later date. Some precedents, where they are ‘in point’ and have been decided by a higher court, are binding and must be followed. Prior decisions by courts of equal or lesser authority or courts of another jurisdictio…

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precession - Torque-free precession, Torque-induced precession, The physics of precession, Precession of the equinoxes

In rotational mechanics, the progressive change in orientation of the axis of rotation. For example, a child's spinning top spins about its own axis, but also wobbles or precesses about the vertical. The Earth precesses in a complicated way. Precession refers to a change in the direction of the axis of a rotating object. In physics, there are two types of precession, torque-free and torque-…

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precession of the equinoxes - Changing pole stars, Polar shift and equinoxes shift, Explanation, Climatic effects, History, Values

A phenomenon which results from slow changes in the direction in space of the Earth's rotation axis. The gravitational attractions of the Sun and Moon tug at the Earth's equatorial bulge, leading to a turning force or ‘couple’ that swings the rotation axis through a cone in space, at an angle of 23·5° to the equatorial plane, on a period of 25 800 years. An important consequence of precession…

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predestination - Predestination and omniscience, Predestination in Christianity, Jewish views, Islamic views, Islam and Christianity

In Christian theology, the doctrine that the ultimate salvation or damnation of each human individual has been ordained beforehand. A source of endless dispute, the doctrine has been interpreted in many ways. It was first fully articulated by Augustine during his controversy with the Pelagians, who upheld the doctrine of free will. The Protestant Reformers Luther and Calvin defended the doctrine, …

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prefabrication

In architecture, the manufacture of parts or the whole of a building in a factory or other place away from the construction site. It was famously used for the rapid construction of the Crystal Palace, London (1851), architect Joseph Paxton. First considered in earnest during the 1920s, it was subsequently put into practice on a wide scale during the post-war years. Although successfully used for m…

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prefect - Ancient Rome, Ecclesiastical, Academic, Modern sub-national administration, Police

In local government, a senior official who is a direct agent of central government. The prefectorial system contrasts with systems of local government that allow for local participation and autonomy, and is found most notably in France since Napoleon, and in Italy since the Risorgimento. It has been criticized for its high degree of centralization, and the power of prefects has declined over the y…

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pregnancy - Determining the beginning of pregnancy and predicting date of birth, Timeline of a typical pregnancy

A physiological process in which female, live-bearing mammals nurture their developing young within the uterus; also known as gestation. It begins when the fertilized ovum embeds itself in the uterine wall (implantation), and ends with the birth of the offspring (parturition). During pregnancy in humans, which lasts on average 40 weeks from the first day of the last menstrual period, menstruation …

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prejudice

Making judgments about individuals based on inadequate or biased information. In the 20th-c, racism - together with the Holocaust and the influx of refugee psychologists and sociologists into the USA in the 1930s - made the study of prejudice a key area of contemporary social psychological research. The search for the roots of prejudice in terms of the individual pathology of the prejudiced led to…

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premium bond - ERNIE, Other meanings, Cultural reference

A UK government security, introduced in 1956, and issued in numbered units of one pound. The accumulated interest on bonds sold is distributed through a lottery in the form of weekly and monthly tax-free cash prizes. Winning numbers are selected by a computer known as ERNIE (Electronic Random Number Indicator Equipment). A Premium Bond is a bond issued by the United Kingdom government's Nat…

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prenatal diagnosis - Reasons for prenatal diagnosis, Ethical and practical issues, Methods of prenatal diagnosis

The assessment of the well-being of the fetus and the detection of abnormalities. Traditional clinical methods have been greatly reinforced by three recent techniques. Ultrasound is simple and safe, and is performed routinely in some countries to establish gestational age, confirm multiple pregnancies, and detect congenital abnormalities, such as spina bifida. Amniocentesis and chorionic villus sa…

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prepared piano - History, In popular music

A piano into which extraneous objects have been inserted, usually between the strings, to alter the timbre of all or selected notes. US composer John Cage and other avant-garde composers have used it since the 1940s. A prepared piano is a piano that has had its sound altered by placing objects (preparations) between or on the strings or on the hammers or dampers. The idea of alt…

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Presbyterianism - Characteristics of Presbyterians, Doctrine, Varieties of Presbyterianism in the United States

The conciliar form of Church government of the Reformed Churches, deriving from the 16th-c Reformation led by John Calvin in Geneva and John Knox in Scotland. Government is by courts at local congregational (eg kirk session), regional (presbytery), and national (General Assembly) levels. Elders (ordained laymen) as well as ministers play a leading part in all courts. Through emigration and mission…

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preschool education - Developmental areas, Ages for and importance of preschool education, Methods of Preschool Education

The provision of education for children under the statutory school age. This can either be in nursery or kindergarten, where there will usually be trained personnel, or in playgroups, where parent volunteers work with playgroup leaders. In some countries the provision of preschool education is widespread, but in others it is almost nonexistent. Preschool education describes the education of…

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prescription

An order for drugs written by a physician to a pharmacist, who will supply the correct medicine to the patient. Originally the sign ? was used to instruct the pharmacist to assemble the ingredients according to written instructions. This sign now simply indicates requests for prepared drugs. Until the 1940s prescriptions were written entirely in Latin. …

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president - Presidents in democratic countries and international organizations, Presidents in dictatorships, Presidential symbols

The name used by a head of state who is not appointed on a hereditary basis. The powers and means of selection can take a variety of forms: some are elected and others appointed. In parliamentary systems, the president performs a largely formal and ceremonial role, ensuring that a government is formed (eg Ireland). In constitutional hybrid systems the president shares the government of the state w…

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Presidential Medal of Freedom - Insignia

The highest American award for civilians in peacetime, given for contributions to the interests of the USA, or to world peace, or for cultural achievements. The Presidential Medal of Freedom is one of the two highest civilian awards in the United States and is bestowed by the President of the United States (the other major civilian award which is considered the equivalent is the Congr…

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Presley (Neville) O'Bannon

US marine officer, born in Fauquier Co, Virginia, USA. Leading the Marine detachment in the expedition to capture Derna, Libya, during the Tripolitan War (Apr 1805), he helped raise the first American flag ever to fly over foreign soil, hence the ‘shores of Tripoli’ reference in the ‘Marine Hymn’. He resigned in 1807 and lived quietly in Kentucky for more than four decades. Presley Nevi…

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pressure - Example, Relative or gauge pressure, Scalar nature of pressure, Kinetic nature of pressure, Negative pressures

Force per unit area; symbol p, units Pa (pascal). A given weight acting on a smaller area corresponds to larger pressure. For an object immersed in a fluid, such as water or air, pressure acts on all sides of the object. It is measured using barometers or pressure gauges. Other common units of pressure are bar and torr. Pressure (symbol: p) is the force per unit area applied on a surface in…

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Prestel

An interactive computer-based information system provided over the telephone network in the UK by British Telecom. It provides access to a wide variety of information sources. Prestel, the brand name for the Post Office's Viewdata technology, was an interactive videotex system developed during the late 1970s and commercially launched in 1979. In common with the Ceefax and ORACLE…

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Prester John - Letter of Prester John, Mongol Empire, Ethiopia, End of the legend, Literary references

A mythical Christian priest-king of a vast empire in C Asia. Reports of his existence, wealth and military might, substantiated by a letter purporting to have come from him in 1165, raised the morale of Christian Europe as it faced the Muslim threat. The story probably arose both from reports of Nestorian Christians in Asia and more obviously of the African Christian kingdom of Ethiopia, which had…

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Preston - History, Geography, Demographics, Landmarks, Economy, Transport, Education, Media, Sport, Famous residents, Twin cities/towns, Trivia

53°46N 2°42W, pop (2001e) 129 600. City and county town of Lancashire, NW England, UK; 45 km/28 mi NW of Manchester, on the R Ribble; site of Royalist defeat in the Civil War (1648); 19th-c centre of the cotton industry; birthplace of Richard Arkwright; city status granted 2002; railway; University of Central Lancashire (1992, formerly Lancashire Polytechnic); electrical goods, engineering, …

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Preston (Smith) Brooks

US representative, born in Edgefield, South Carolina, USA. A gentleman farmer, lawyer, and veteran of the Mexican War (1846–8), he served in Congress (Democrat, South Carolina, 1853–7). When Senator Charles Sumner vilified his uncle, A P Butler, in heated debate over the Kansas-Nebraska Bill, Brooks retaliated by smashing Sumner's head with his cane. The 1856 incident became the focus of partisa…

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Preston Sturges - Biography, Examples of Sturges dialogue, Feature-films filmography, Adaptations, Published screenplays, Awards

Film-maker and scriptwriter, born in Chicago, Illinois, USA. He studied in the USA and Europe, and became a businessman and inventor before succeeding in the 1940s with freewheeling comedies that combined wit, slapstick, and social concerns. His enduring hits include The Lady Eve (1941), Sullivan's Travels (1942), and Hail, the Conquering Hero (1944). He received an Oscar for the script of The Gre…

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Prestonpans - History, Modern Prestonpans

55°57N 3°00W, pop (2000e) 8080. Town in East Lothian, E Scotland, UK; on S shore of Firth of Forth, 5 km/3 mi NE of Musselburgh; railway; coal processing; site of Scottish victory over the English (1745). Prestonpans is a small town to the East of Edinburgh, Scotland, in the unitary council area of East Lothian. It is the site of the 1745 Battle of Prestonpans, and has a history dating…

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Prestwick - Transport, Education, Many Kings passed through Prestwick

55°30N 3°12W, pop (2000e) 13 700. Town in South Ayrshire, SW Scotland, UK; on the W coast, 4·8 km/3 mi N of Ayr; airport (the official international gateway for Scotland); railway; aerospace engineering. Prestwick is a town located in South Ayrshire on the central west coast of Scotland, approximately 30 miles to the south-west of Glasgow. Prestwick has been at the centre…

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Pretoria - Demographics, History

25°45S 28°12E, pop (2000e) 613 000 (metropolitan area). Administrative capital of South Africa, and alternative capital of Gauteng province; 48 km/30 mi NE of Johannesburg; altitude 1369 m/4491 ft; founded, 1855; capital of South African Republic, 1881; railway; two universities (1873, 1908); railway engineering, vehicles, iron and steel, chemicals, cement, leather; Voortrekker Memorial, P…

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preventive medicine - As a medical specialty, Rose's theorem

A branch of medical practice that is concerned with the prevention of disease. This is achieved by measures that (1) control the environment, such as clean air legislation, (2) ensure a hygienic and suitable food and water supply, (3) promote mass medication (eg schemes of immunization), (4) organize programmes for the eradication of disease (eg smallpox, diphtheria), and (5) promote safer life st…

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Priam - Marriage and issue, Life, In later literature, In Popular culture

In Greek legend, the King of Troy. He was son of Laomedon, and husband of Hecuba, and is presented in the Iliad as an old man. When Hector was killed, he went secretly to Achilles to beg his son's body for burial. At the sack of Troy, he was killed by Neoptolemus. In Greek mythology, Priam (Greek Πρίαμος, Priamos) was the king of Troy during the Trojan War, and youngest son of Laomed…

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Pribilof Islands

Group of four islands in the Bering Sea, Alaska, USA; two inhabited (St Paul, St George); area 168 km²/65 sq mi; centre of seal fur trade. The Pribilof Islands (often called the Fur Seal Islands, Russian: Kotovi) are a group of four volcanic islands, part of Alaska, lying in the Bering Sea, about 200 miles north of Unalaska and 200 miles south of Cape Newenham, the nearest…

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priest - In Judaism, Dress, Assistant Priest

The person authorized to sacrifice. In Christianity, the term derives from the Old Testament sacrificial system, and developed in the New Testament with Jesus Christ as great High Priest. Now, mainly in Roman Catholic, Orthodox, and Anglican usage, it refers to an ordained officer authorized to administer the sacraments, in particular the Eucharist (the sacrifice of the Mass). Priests have …

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primary

In politics, an election to choose the candidates for an election to public office. It differs from other forms of candidate selection in that the primary election is not organized by political parties, but by the government authority for which the election is to be held. The procedure is most commonly associated with the USA, but there are various forms of primary, and several ways in which polit…

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primary education - General information

The first phase of statutory education, usually covering the years from 5 or 6 up to 11 or 12. In most countries, the emphasis is on the coverage of a wide range of subjects and themes usually taught by the class teacher. In some countries there is more specialist teaching, especially in fields such as music, mathematics, and science, and children may have specialist rather than generalist teacher…

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primate (religion) - Roman Catholic Church, Anglican Communion

The most senior bishop of a given area; for example, in the Church of England the Archbishop of Canterbury is primate of All England. Originally, the name applied to the metropolitan of a province, and then to the patriarch. In the Western Church, a Primate is an archbishop (or rarely a suffragan - or exempt bishop) of an episcopal see (called a primas) which confers precedence over the oth…

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primate (zoology) - Habitat, Classification and evolution

A mammal of the order Primates (c.180 species); most inhabit tropical forests; both eyes face forwards; hands and (usually) feet with grasping ‘opposable thumb’, used for climbing; cerebral hemispheres of brain well developed. Their classification is unsettled, but living species are usually placed in two suborders: the Strepsirhini (prosimians) and the Haplorhini (tarsiers and Anthropoidea). …

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prime minister

The leader of and usually head of a government; also known as a premier. In general, prime ministers have to work through collective decision-making in a cabinet, although they can enjoy certain separate powers. In electoral systems, they are usually the leader of the largest party or coalition in parliament; unlike presidents, their power base is more that of the party than that of personality. …

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prime number - History of prime numbers, Prime divisors, Properties of primes, The number of prime numbers

In mathematics, a positive integer greater than 1 that has no divisors other than 1 and itself. Primes have always had an important place in the theory of numbers. Number theorists have tried to devise functions f(n) which produce only prime numbers for positive integer values of n, but so far, all have failed. The function f(n) = n2 ? n + 41 yields primes for all n < 41; f(n) = n2 ? 7…

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primitivism - Some characteristics of primitivism, The origins of primitivism in western art, Primitivism and Colonialism/Racism

In modern art, the deliberate rejection of Western techniques and skills in the pursuit of ‘stronger’ effects found in such domains as African tribal or Oceanic art. The word may therefore be applied to Gauguin, and to Picasso's work from c.1906. It is sometimes referred to as ‘naive art’. Primitivism is an artistic movement which originated as a reaction to the Enlightenment. …

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Primo Levi - Early life, Auschwitz, Writing, Levi's views on Nazism and Antisemitism, Death

Writer and chemist, born in Turin, Piedmont, NW Italy, to Jewish parents. On completing his schooling he enrolled at Turin University to study chemistry. During the war he joined a small guerrilla force, but he was betrayed and despatched to Auschwitz. He was one of the few to survive, and returned to Italy in 1945. All of his writings attempt to understand the nature of Nazi barbarity and the var…

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primrose - People with the surname Primrose

A stemless perennial (Primula vulgaris) native to Europe, W Asia, and N Africa; a rosette of crinkled, tongue-shaped leaves; flowers long-stalked with a tubular calyx and spreading, pale yellow, rarely pink petals. It is a plant of woods and hedges, decreasing in some places because of excessive picking. The garden polyanthus is derived from a hybrid with the cowslip. (Family: Primulaceae.) …

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Prince - Historical background and the two main notions of princehood, Genealogical Princes, by birth or equivalent

Pop-singer and composer, born in Minneapolis, Minnesota, USA. Named after the Prince Roger Trio, a jazz band in which his father was a pianist, he was signed to Warner Brother Records as a teenager, and released For You in 1978. Subsequent albums included Prince (1979), Dirty Mind (1980), and Controversy (1981), which attracted increasing controversy with their tendency to mix religious and overtl…

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Prince Albert

Prince Consort to Queen Victoria, born at Schloss Rosenau, near Coburg, EC Germany, the younger son of the Duke of Saxe-Coburg-Gotha and Louisa, daughter of the Duke of Saxe-Coburg-Altenburg. He studied in Brussels and Bonn, and in 1840 married his first cousin, Queen Victoria - a marriage that became a lifelong love match. Ministerial distrust and public misgivings because of his German connectio…

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Prince Edward (Antony Richard Louis)

Prince of the United Kingdom, the third son of Queen Elizabeth II. He studied at Gordonstoun School, Scotland, then spent several months as a house tutor in New Zealand at Wanganui School. After graduating from Cambridge with a degree in history, he joined the Royal Marines in 1986, but left the following year and began a career in the theatre, beginning as a production assistant with Andrew Lloyd…

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Prince Edward Island - Municipalities

pop (2000e) 145 600; area 5660 km²/2185 sq mi. Province in E Canada; island in the Gulf of St Lawrence, separated from the mainland (SW) by Northumberland Strait; irregular coastline; rises to 142 m/466 ft; capital, Charlottetown; other towns include Summerside, Tignish, Souris; occupied first by Micmac nation; visited by Cartier, 1534; French claim as Île St Jean; settled by Acadians; ca…

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Prince Eugene of Savoy - Early life, Turkish Wars, War of the Grand Alliance, Zenta, War of the Spanish Succession

Austrian general, born in Paris, France. He was refused a commission by Louis XIV of France, and entered the service of the Emperor Leopold against the Turks. Made field marshal in 1693, he defeated the Turks on several occasions, putting an end to their power in Hungary (1699–1718). He fought against France in two wars between 1689 and 1714, and while in command of the imperial army he helped Ma…

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Prince Michael of Kent - Marriage, Controversy, Titles and honours, Notes and references

British prince, the younger brother of Edward, Duke of Kent. He married in 1978 Baroness Marie-Christine Von Reibniz, and their children are Frederick Michael George David Louis, Lord Frederick Windsor (1979– ) and Gabriella Marina Alexandra Ophelia, Lady Gabriella (Ella) Windsor (1981– ). As the third child of George V's fourth son, it was not expected that Prince Michael of Kent would u…

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Prince of Wales - Princes of Wales, past and present

In the UK, the title conferred (by custom, not law) on the sovereign's eldest son. Wales was ruled by a succession of independent princes from the 5th-c; the first to be acknowledged by an English king was Llewelyn ap Gruffudd (r.1246–82) in 1267. Tradition holds that after the death of Llewelyn in battle (against the English) and the execution of his brother, Edward I presented his own infant so…

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Princess Charlotte (Augusta)

Princess of Great Britain and Ireland, the only daughter of George IV and Caroline of Brunswick, who separated immediately after her birth. The heir to the British throne, she was brought up in strict seclusion. In 1816 she married Prince Leopold of Saxe-Coburg (later to be King Leopold I of the Belgians), but died in childbirth the following year. Princess Charlotte may refer to: …

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Princess Royal - First marriage, Princess Royal, Charity work, Honorary military appointments, Court cases, Titles and honours

A title sometimes bestowed on the eldest, or only, daughter of a sovereign. George V's daughter Mary was Princess Royal until her death in 1965; the title was conferred by the Queen on Princess Anne in 1987. The Princess Anne, Princess Royal, (Anne Elizabeth Alice Louise Laurence; width: 240px;" cellpadding="4" cellspacing="0"> On 14 November 1973 Princess Anne married Mark Phil…

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Princeton - Places, Other

40°21N 74°40W, pop (2000e) 14 200. Borough in Mercer Co, WC New Jersey, USA, on the Millstone R; founded by Quakers, 1696; scene of a British defeat by George Washington, 1777; a noted centre for education and research; university (1746); birthplace of Paul Robeson; home of Einstein after his emigration to the USA. Princeton may refer to: …

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principality - Terminology, Western principalities, Other principalities, Other uses

A type of absolute rule in C and N Italy in the 15th-c. It evolved from the signoria, when the hereditary possession of a territory was officially recognized by pope and emperor, and its ruler was awarded sovereign powers and the title of marquis or duke. A principality (or princedom) is a monarchical feudatory or sovereign state, ruled or reigned over by a Monarch with the title of prince …

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printing - History, Modern printing technology, Digital Printing

A set of techniques for placing an image on a foundation in a controlled sequence of identical copies. The image may be verbal, illustrative or abstract, in one or many colours; the foundation is generally paper; and the colouring agent is generally ink. The techniques include relief, planographic (surface), and intaglio (recess) printing. The principal forms of relief printing are letterpress and…

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prion - PrP and the prion hypothesis, Prions in yeast and other fungi, Molecular properties

A petrel, native to S oceans; uses very stout bill with sieve-like edge to strain minute crustaceans from water. (Genus: Pachyptila, perhaps 6 species; experts disagree. Family: Procellariidae.) A prion (IPA: [ˈpriːɒn] .listen?(help·info)) — short for proteinaceous infectious particle (by analogy to virion) — is a type of infectious agent made only of protein. Prions are belie…

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Priscian - Works

Latin grammarian, born in Caesarea. At the beginning of the 6th-c he taught Latin at Constantinople. As well as his 18-volume Institutiones grammaticae, which was influential in the Middle Ages, he wrote six smaller grammatical treatises and two hexameter poems. Priscianus Caesariensis (fl. 500 AD), commonly known as Priscian was a Latin grammarian who wrote the Institutiones grammaticae ("…

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Priscillian - Priscillian's career, Priscillian's contemporary following, Continued Priscillianism, Writings and rediscovery

Christian bishop, born in Trier, Gaul (modern Germany). He was excommunicated by a synod at Saragossa in 380, then tolerated, but ultimately executed - the first case of capital punishment for heresy in the history of the Church. The Prisicillian doctrine, said to have been brought to Spain from Egypt, contained Gnostic and Manichaean elements, and was based on dualism. Priscillian of Ávil…

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prism

In mathematics, a solid geometrical figure: its section is a rectilineal figure, with parallel edges. In optics, it is a transparent object used to produce or study the refraction and dispersion of light. It may be made of glass, plastic, or liquid in a hollow prism. Prism may refer to: PRISM may stand for: …

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prison - Other names and uses of the term, Prison design and facilities

That part of the penal system where criminals are held in custody for varying lengths of time determined by the courts as punishment for offences. Prisons developed rapidly from the early 19th-c; before then, banishment and corporal or capital punishment were the main ways of dealing with offenders. Subsequently, imprisonment itself came to be seen as both an adequate penalty and acceptable means …

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privatization - Overview, Types of Privatization/Methods of Government Disinvestment

The return to private ownership of organizations formerly owned by the state. The government issues shares in the company to be privatized, and offers them for sale to the public. The company therefore becomes answerable to the shareholders and not to the government. Several cases of privatization took place in Britain in the 1980s, including British Telecom and British Gas. The government was abl…

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privet - Trivia

A mostly temperate, evergreen or deciduous shrub or small tree; leaves opposite, leathery; flowers tubular with four spreading lobes, creamy, fragrant, in loose conical inflorescences; berries black or purple, poisonous. Several species are commonly used for garden hedges. (Genus: Ligustrum, c.40 species. Family: Oleaceae.) Privet was originally the name for the European semi-evergreen shru…

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Privy Council

A body which advises the British monarch, appointed by the crown. In previous times, particularly the Tudor period, it was a highly influential group, and might be regarded as the precursor of the cabinet. Today its role is largely formal, enacting subordinate legislation (proclamations and Orders in Council). Its membership is over 300, but the quorum is three. It is an important part of t…

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Prix de l'Arc de Triomphe

The richest horse race in Europe, held at the end of the season over 2400 m/2625 yd at Longchamp, near Paris, on the first Sunday in October. First run in 1920, it is the leading race in Europe for horses at least three years old. …

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Prix Goncourt

France's most prestigious literary prize for fiction, given annually since 1903 by the Académie Goncourt (founded by Edmond de Goncourt). The award carries a symbolic prize of 50 francs but guarantees huge sales for the author. The Prix Goncourt is the most prestigious prize in French literature, given to the author of "the best and most imaginative prose work of the year". Moselly, Le Rou…

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Prix Renaudot - Prix Renaudot laureates

A French literary prize awarded for the best novel of the previous year. It takes its name from Théophraste Renaudot (c.1586–1653), founder of the weekly paper La Gazette. The prize was first awarded in 1926 and is presented annually at a Parisian restaurant. Past winners include Louis-Ferdinand Céline, Michel Butor, and Louis Aragon. …

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Prizren - Prizren now

42°12N 20°43E, pop (2001e) 114 900. Town in Kosovo autonomous province, SW Serbia; on R Prizrenska Bistrica, near the Albanian frontier; built on the site of a Roman town (Theranda); important mediaeval trade centre; part of Albania, 1941–4; railway; tourism, gold and silver work; old town, mosques. Prizren (Albanian Prizren/Prizreni, Serbian: Призрен / Prizren) is a historical …

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probability theory - A somewhat more abstract view of probability, Philosophy of application of probability, Bibliography

The mathematical study of relative probabilities in processes involving uncertainty, for example tossing a coin or rolling dice. The foundations of the subject were laid by Pascal and Fermat in the 17th-c, and it was further systematized in the 20th-c by the Russian mathematician Andrei Nicolaevich Kolmogorov (1903–87). Mathematicians and actuaries think of probabilities as numbers in the …

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probate - Probate in the United States

The official proving of a will. The executor of the will applies to the court (eg in England and Wales, the High Court, Family Division, and in the USA, generally Probate Courts or Registrars) for a certificate confirming the validity of the will and the authority of the executor to administer the estate of the deceased. The term is not used in all jurisdictions (eg in Scotland, where the equivale…

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probation - History of Probation: Origins and Evolution

A method of dealing with offenders over the age of 16 where, instead of a sentence of imprisonment, a court may order the offender to be supervised for a fixed period of no longer than three years by a probation officer. Offenders must agree to be placed on probation after the obligations under the order are explained to them. A court may in addition require the offender to perform unpaid work for…

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proboscis monkey - Trivia

An Old World monkey (Nasalis larvatus) native to Borneo; pale with darker ‘cap’ on head, and dark back; long tail; protruding nose, which in adult males becomes bulbous and pendulous; excellent swimmer; inhabits forest near fresh water; eats leaves. The Proboscis Monkey, Nasalis larvatus also known as Long-nosed Monkey is a reddish-brown arboreal Old World monkey. …

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procedural programming - Procedures and modularity, Comparison with imperative programming, Comparison with object-oriented programming, Procedural programming languages

A form of computer programming in which statements which instruct the computer to carry out operations and data are organized in sequence. Most procedural programming languages can be compiled into a set of instructions for the computer to obey. Examples of procedural languages are FORTRAN and PASCAL. Procedural programming is sometimes used as a synonym for imperative programming (specifyi…

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Proclus - Biography, Works, System, Influence, Bibliography

Greek Neoplatonist philosopher, born in Constantinople. He studied at Alexandria and Athens, and became the last head of Plato's Academy. His approach, based on Plotinus, combined the Roman, Syrian and Alexandrian schools of thought in Greek philosophy into one theological metaphysic. His works were translated into Arabic and Latin, and were influential in the Middle Ages. Proclus Lycaeus (…

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Procopius - Life, Writings, Context

Byzantine historian, born in Caesarea (now in Israel). He studied law, and accompanied Belisarius against the Persians (526), the Vandals in Africa (533), and the Ostrogoths in Italy (536). He was highly honoured by Justinian, and seems to have been appointed prefect of Constantinople in 562. His principal works are histories of the Persian, Vandal, and Gothic wars, and an attack on the court of J…

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Procrustes - Derived meanings

In the legend of Theseus, a robber, living in Attica, who made travellers lie on his bed, and either cut or lengthened them to fit it; his name means ‘the stretcher’. Theseus gave him the same treatment, and killed him. In Greek mythology, Procrustes (the stretcher), also known as Damastes (subduer) and Polypemon (harming much), was a bandit from Attica. Nobody would ever fit in the…

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procurator fiscal - Prosecution of crimes, Origins

A public offical in Scotland who, acting on behalf of the Lord Advocate, is responsible for initiating and pursuing the prosecution of crimes and offences, reported to them by the police, in the sheriff court and the district court. The ‘fiscal’ is also responsible for reporting serious crimes to the Crown Office, which may merit prosecution in the High Court, as well as for investigating all ca…

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producer

In the film industry, the person who brings the initial concept to practical reality - organizing finance and budgetary control, choosing the director, and holding the balance between the director and other important members of the production team, including the principal artists. Producers exercise day-to-day administration to ensure that the shooting schedule is maintained and unforeseen crises …

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productivity - Measures of factor productivity, Productivity studies, Increases in productivity, Labour productivity, Marx on productivity

The ratio of output to input in an industrial context. It usually refers to the quantity of goods or commodities produced in relation to the number of employees engaged in the operation (labour productivity). Total productivity includes the input of capital also. Low productivity is the major cause of a company's decline, since it results in high costs per unit, and therefore high prices that are …

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Professor Longhair - Discography

Blues musician, born in Bogalusa, Louisiana, USA. As a pianist and singer, he was an innovator of post-war New Orleans rhythm-and-blues. He worked outside music as a stuntman, dancer, boxer, and gambler until 1947, when he formed his first band. In 1949 he made several recordings in his prototypical style, but performed only sporadically for the next two decades. His appearances at major festivals…

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profit - Economic definitions of profit, Accounting definitions of profit, More varieties of profit

The difference for a company between its sales revenue and the costs attributable to those sales. Profit may be calculated before or after deducting interest payments, and before or after deducting taxation charges. The surplus may be paid out to shareholders as a dividend, or retained by the business (as reserves) to finance capital expenditure. Profit sharing is a scheme whereby a percentage of …

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progesterone - Chemistry, Sources, Levels, Effects, Medical Applications

A steroid hormone present in both sexes of all vertebrates. In mammals it is critical for the establishment and maintenance of pregnancy. In humans it is primarily secreted by the ovaries and placenta. It acts to prepare the uterus for implantation of the embryo, inhibits ovulation during pregnancy, and prepares the breasts for lactation. It also acts to raise body temperature. Progesterone…

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prognosis - History

In medicine, an assessment of the likely outcome of a disease and its treatment. A good prognosis implies that the patient is likely to recover completely; a poor prognosis implies that the disease is likely to prove terminal within a short period. Prognosis (older Greek πρόγνωσις, modern Greek πρόγνωση - literally fore-knowing, foreseeing) is a medical term denoting the do…

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programming language - Definitions, Purpose, Elements, Practice, History, Taxonomies

An artificial language which allows people to instruct computers to carry out specific tasks; also known as a computer language. Many programming languages have been developed; among the relatively common high-level languages are ADA, APL, ALGOL, BASIC, C, C++, COBOL, CORAL, FORTH, FORTRAN, LISP, PASCAL, PROLOG, and JAVA (see separate entries). In addition there are numerous low-level languages wh…

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Progress spacecraft - Design, Versions, Current status

An uncrewed version of the Soviet Soyuz crewed spacecraft, modified as a resupply vehicle for the Salyut and Mir space stations. After unloading, the spacecraft is separated and removed from orbit to burn up in the atmosphere. The Progress is a Russian an expendable freighter spacecraft. It was derived from the Soyuz spacecraft, and is launched with the Soyuz launch vehicle. It is currently…

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Progressive Party

(1912–16, 1924) The name used by three separate third-party political initiatives in the USA. The first, essentially a breakaway from the Republicans, centred on former president Theodore Roosevelt (in office 1901–9), who was its presidential candidate in 1912. The second developed in 1924 from midwestern farmer and labour discontent. Its presidential candidate, Senator Robert La Follette (1855

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Prohibition - United States, Canada, Britain, Nordic countries, Middle East, North Africa, and Central Asia, Australia

(1920–33) An attempt to stop the sale of alcoholic drinks in the USA, authorized by the Eighteenth Amendment to the Constitution (1919) and the Volstead Act (1920). Prohibition met great resistance, especially in urban immigrant communities, and generated a large bootlegging industry. It was ended by the repeal of the 18th amendment in 1933. Prohibition is any of several periods during whi…

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projective geometry - Description, Duality, History, Forms of the living world

The study of what geometric figures have in common with their shadows - for example, the properties of being a line, or a curve defined by a polynomial of a given degree. The subject was invented by Girard Desargues (1591–1661) and used to simplify the study of conics: all ellipses, parabolas, and hyperbolas are projectively equivalent. Newton similarly reduced all cubic curves to five types. The…

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projector

An apparatus for presenting an enlarged image on a screen from a transparency such as a photographic slide or film. In a film projector, each frame is held stationary at an illuminated aperture for a brief period, and then advanced by an intermittent sprocket or reciprocating claw, the light being cut off by a rotating shutter during the movement. The sound track on the film is reproduced at a sep…

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prolactin - Effects, Variance in levels, Structure, Prolactin receptor, Diagnostic use

A hormone secreted by the front part of the pituitary gland (adenohypophysis) which initiates lactation in mammals and stimulates the production of another hormone, progesterone, by the corpus luteum. Prolactin is a peptide hormone synthesised and secreted by lactotrope cells in the adenohypophysis (anterior pituitary gland). Pituitary prolactin secretion is regulated by neuroendocrin…

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proletariat

In radical and socialist philosophy, a term coined to denote the working class, ie those who live by their labour and do not own property. It is particularly important in Marxist and communist ideology. Lumpenproletariat was coined by Marx to refer to the underclass in big cities from whom class identification could not be expected. The proletariat (from Latin proles, offspring) is a term u…

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PROLOG - Data types, Facts, Rules, Execution, Parsing, Comparison of Implementations, Extensions

A high-level programming language based on mathematical logic, widely used in artificial intelligence applications. It was developed at the University of Aix-Marseille in France and in the UK at Imperial College and Edinburgh University. PROLOG has to some extent replaced LISP, mainly in Europe. Prolog is a logic programming language. In some ways Prolog is a subset of Planner, e.g., see Ko…

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PROM - Prom King and Queen, Related Social Gatherings

Acronym for programmable read-only memory, a special type of integrated circuit read-only memory (ROM) into which the user can write data after manufacture. Once written, the data cannot be altered. In the United States and Canada, a prom, short for promenade, is used to describe a formal dance held at the end of the high school academic year. In the United Kingdom the term is more wi…

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promenade concert - Further reading

A musical performance, especially by an orchestra, during which some at least of the audience are offered floor space, without seats, at reduced prices. The London ‘proms’ were started at the Queen's Hall by Sir Henry Wood in 1895; they transferred to the Royal Albert Hall in 1941; over 6000 concerts have taken place since they began. Although the term Promenade Concert is normally associ…

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Prometheus - Worship, Myth, Comparative perspectives, Promethean myth in culture

In Greek mythology, a Titan, son of Iapetus and brother of Epimetheus; originally a trickster who outwits Zeus; his name means ‘the foreseeing’. He made human beings out of clay, and taught them the arts of civilization. He stole fire from heaven to help mankind, whom Zeus wished to destroy, and was punished by being chained to a rock in the Caucasus; every day an eagle fed on his liver, which g…

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promissory note

A signed document containing a written promise to pay a sum of money on or by a specific date. The document is legally binding and is signed, for example, when a bank customer takes out a loan. A particular form is a commercial paper, issued by large companies, which can be bought and sold. The terms of a note typically include the principal amount, the interest rate if any, and the maturit…

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promoter (genetics) - Promoter elements, Promoter sequences, Binding, Diseases associated with aberrant promoter function

The non-coding region immediately next to the start of a gene which acts as a ‘switch’ to allow transcription. Various proteins (known as transcription factors) bind to the promoter DNA sequences which ultimately have the effect of recruiting the enzyme RNA polymerase. This begins the process of transcription of the gene. In genetics, a promoter is a DNA sequence that enables a gene to be…

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pronghorn

A North American antelope (Antilocapra americana); male called prongbuck; pale brown with prominent eyes; female horns short; male horns with frontal ‘prong’ and backward-curving tips; outer layer of horns shed each year; will approach moving objects (including predators); inhabits grasslands. The Pronghorn (Antilocapra americana) is the only surviving member of the family Antilocapridae,…

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propane - Properties and Reactions, Sources, History, Popular culture

C3H8, boiling point ?42°C. The third in the alkane series of hydrocarbons; a gas obtained from petroleum and natural gas, used as a fuel and a refrigerant. When commonly sold as fuel, it is also known as liquified petroleum gas (LPG or LP-gas) and can be a mixture of propane with smaller amounts of propylene, butane and butylene. In North America, LPG is primarily propane (at least 9…

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propellant (chemistry) - Aerosol sprays, Solid propellant rockets and projectiles, Liquid propellant rockets, Sources and references

An explosive which produces a violent but steady pressure, such as is needed to expel a projectile from a gun. Gunpowder, suitably graded, was the first. After the high explosive properties of nitroglycerine and nitrocellulose had been discovered, attempts were made to moderate their disruptive effect to make them useful as propellants. Success was achieved with various gelatinized mixtures, notab…

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propellant (fuel) - Aerosol sprays, Solid propellant rockets and projectiles, Liquid propellant rockets, Sources and references

A fuel which functions not by exerting pressure but by the recoil effect of the expulsion of gases at high speed (which is why a rocket can be propelled in empty space). Many forms exist, some solid, some liquid (eg hydrazine with dinitrogen tetroxide). A propellant is a material that is used to move an object by applying a motive force. Common chemical propellants consist of a fuel, like g…

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propeller - History, Slang, Aviation, Marine

A device used principally by ships and aeroplanes to transform the rotational energy of an engine into directed thrust. To accomplish this, the propeller is fitted with blades radiating from a central hub, each blade being of aerofoil cross section. As the propeller rotates, the water or air is accelerated backwards, producing an opposite reactive force in the propeller and its shaft. This reactiv…

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property - General characteristics, Theories of property, Property in philosophy, Types of property, What can be property?

Something owned or possessed - a notion whose precise definition varies greatly between different jurisdictions. In Anglo–US law, real property includes lands and buildings; also, intangible interests in land, such as easements. Other kinds of property are known as personal property. Leases are classified as personal property, and are also referred to as ‘chattels real’. Chattels are movable go…

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propfan - Propfan engines

An aircraft propeller designed for a turbo-engine, enabling large amounts of power to be delivered by increasing the number and area of the blades in comparison with a conventional aircraft propeller. A particular feature of such propellers is the swept back or ‘skew’ nature of the blades, which allows quieter operation for the rotational speeds involved. A propfan is a modified turbofan …

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prophet - Sociological taxonomy of prophets, Prophets in the Tanakh (Hebrew Bible), Prophets in Jewish thought

One who is inspired to reveal a message from a divine being; an important figure in many religious traditions, sometimes with cultic functions, but sometimes a lone figure opposing the established cult or social order (eg Jeremiah, Amos, and Hosea in the Hebrew Bible). Although their messages may acquire an enduring relevance, they usually address a specific situation or problem. In the New Testam…

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proportional counter

A device for monitoring the path of charged particles produced in particle physics experiments. Arrays of wire electrodes give an electric field which accelerates ions produced by a passage of charged particles. The ions cause pulses in electrodes that are recorded electronically to give a map of the particle track. Drift chambers and multi-wire proportional chambers are common forms of proportion…

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proportional representation - Mixed Election Systems, Coalition Governments, History, Methods of proportional representation, Partial Proportionality

Any system of voting designed to ensure that representatives are elected in numbers proportionate to their support among those voting in an election. There are many voting methods, none of which achieves perfect proportionality. In the list system the number of candidates on a party's list who are elected depends on the proportion of votes they receive in national elections. In the single transfer…

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proscenium - Other forms of theater staging

An arch and opening of a stage wall separating the auditorium of a theatre from the acting and scenic area. From its origins in the stagecraft of Peruzzi (1481–1537), Serlio (1475–1554) and others, its development, linked to a concept of theatrical illusion, dominated Western drama until the early 20th-c. In its early form, it was a frame for perspective scenery, and a permanent structure, with …

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prose - History, Styles, Examples

Non-metrical writing, or indeed speech (Molière's M Jourdain was impressed to realize that he spoke prose). There is a natural tendency to regard prose as direct and unadorned, the clear pane of expression beside the stained glass of poetry. Such limpid prose was recommended to the members of the Royal Society in 1667 - an attitude which continues to be found in such works as Ernest Gowers' Plain…

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prosimian - Classification

A primate of the suborder Strepsirhini (40 species); wet nose with slit-like nostrils; tip of nose, between nostrils, with an obvious vertical groove; also known as primitive primate. Prosimians are the most primitive extant primates; The adapids are an extinct grouping that were most certainly prosimians and closely related to the strepsirhines. The prosimians were …

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prosopography

The study of human behaviour through collective biography, aiming to explain people's actions through knowledge of their personal backgrounds - sex, education, age, wealth, class, and family relations. It was applied to 18th-c British history by Sir Lewis Namier, but found to be of limited value in periods of ideological division, such as the 16th-c and 17th-c. Prosopography is an important…

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Prospero Alpini

Botanist and physician, born in Marostica, NE Italy. While in Cairo he observed the sexual fertilization of the date palm, in which male and female flowers are on different trees, and described 57 wild or cultivated species in Egypt. In 1594 he became lecturer in botany at Padua, and director of the botanic garden there (1603). His De medecina Egyptorum (1591) brought the coffee plant and the bana…

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Protagoras - Protagoras and the scientific method

The earliest self-proclaimed Greek Sophist, born in Abdera, Greece. He taught mainly in Athens, presenting a system of practical wisdom fitted to train people for citizen's duties, and based on the doctrine that ‘man is the measure of all things’. His doctrine that all beliefs are true was examined in great detail and rejected by Plato. All his works are lost except a fragment of his treatise On…

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protea

A shrub or small tree, native to tropical and especially S Africa, where they are very diverse; leaves entire or divided, leathery. The large and often spectacular ‘flowers’ are actually inflorescences containing numerous small true flowers in the centre, surrounded by stiff, often brightly-coloured, petal-like bracts. (Genus: Protea, 130 species. Family: Proteaceae.) Protea is both the b…

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protectionism - Current world trends

A government policy of protecting domestic industries against foreign competition. Devices used include tariffs, quotas on imports, subsidies for domestic firms, and preference in state purchasing. The industries may be chosen for protection as ‘infants’, which the government would like to grow, as declining sectors where the government wants to avoid unemployment, or because they are thought vi…

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Protectorate - Rationale, Other protectorates, Contemporary usage by the United States

A regime established by the Instrument of Government, the work of army conservatives, England's only written constitution. The Lord Protectors, Oliver Cromwell (ruled 1653–8) and his son Richard (ruled 1658–9), issued ordinances and controlled the armed forces, subject to the advice of a Council of State and with Parliament as legislative partner. It failed to win support, and its collapse led t…

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protectorate - Rationale, Other protectorates, Contemporary usage by the United States

A territory over which the protecting state enjoys power and jurisdiction short of full sovereignty; not formally annexed, it can come about by treaty, grant, or usage. A protected state is a form of protectorate where the territory is more like a unified state and has its own identifiable rulers. The commonest types were the 19th–20th-c colonial protectorates, Botswana being a British example, a…

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protein - Biochemistry, Synthesis, Structure of Proteins, Cellular functions, Methods of study, History

One of the three essential types of energy foods. It is a natural condensation polymer of amino acids occurring mainly as structural tissue in animals (fibrous proteins, mainly water insoluble, eg silk) but also as enzymes in both animals and plants (globular proteins, largely water soluble, eg haemoglobin). Nearly all proteins are derived from 20 amino acids. Proteins are large organic com…

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Protestantism - Basic theological tenets of the Reformation, Later development, Protestant denominations, Number of Protestants

The generic term for expressions of Christian faith originating from the 16th-c Reformation as a protest against Roman Catholicism. Common characteristics include the authority of scripture, justification by faith alone, and the priesthood of all believers. The original groupings were those who followed Luther, Calvin, and Zwingli, and the term now embraces most non-Roman Catholic or non-Orthodox …

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Proteus - The myth of Proteus, "Proteus" in modern fiction, "Proteus" in gaming

In Greek mythology, a sea god, associated with seals, and a shape-changer; he will give answers to questions after a wrestling match. He is sometimes to be found on the island of Pharos, in Egypt, where Menelaus wrestled with him. In Greek mythology, Proteus is an early sea-god, one of several deities whom Homer calls the "Old Man of the Sea", whose name suggests the "first", as protogonos …

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proton

A component particle of the atomic nucleus; symbol p; mass 1·673 × 10?27 kg (938·3 MeV), charge +1, spin ½. It is held in the nucleus by strong nuclear force, sufficient to overcome the repulsion due to other protons. Free protons are not known to decay. In physics, the proton (Greek πρῶτον proton = first) is a subatomic particle with an electric charge of one positive fundame…

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protoplasm - History of the term

The complex, translucent substance that makes up every living cell. It includes the plasma membrane, but excludes such elements as ingested material and masses of secretion. In eucaryotes, protoplasm is divisible into nucleoplasm (the protoplasm in the nucleus) and cytoplasm (the protoplasm in the rest of the cell). In biology, protoplasm is the living substance inside the cell. It is also …

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protostar - Heating due to gravitational energy

A collapsing sphere of gas, of sufficient mass to make a star, but in which nuclear reactions have not yet started. Such objects can be detected with infrared telescopes because of the heat released by the collapse. The phase lasts 105–107 years. A Protostar is a stage in the development of a star and it is a period after clouds of hydrogen, helium and dust begin to contract and before the…

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Protozoa

A diverse group of unicellular micro-organisms found free-living, as consumers of organic matter, in all kinds of habitats, and as parasites or associates of other organisms; typically possess a single nucleus, sometimes two or more; usually reproduce by splitting in two (binary fission), but sexual reproductive processes are known to occur; includes many disease-causing organisms. Protozoa…

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Provence - History, Geography, Climate, Sights, Culture

Former province in SE France on the Mediterranean coast, now occupying departments of Bouches-du-Rhône, Var, Basses-Alpes, and parts of Alpes-Maritimes and Vaucluse; formerly part of the kingdom of Arles; part of France, 1481; distinctive Romance dialect; coal, bauxite, lead, zinc, salt; market-gardening, grapes, olives, perfumes, tourism (especially on Riviera). Provence has been inhabite…

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Providence - Geography and climate, Demographics, Neighborhoods, Economy, Government, Education, Culture, Infrastructure

41°49N 71°24W, pop (2000e) 173 600. Capital of Rhode Island, USA; the smallest state capital in land area; port at the head of Providence R, in Providence County; established, 1636; city status, 1832; an early haven for religious dissenters; airport; railway; Brown University (1764); jewellery and silverware, fabricated metals, equipment; first Baptist and Unitarian churches, State Capitol, mu…

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providence - Geography and climate, Demographics, Neighborhoods, Economy, Government, Education, Culture, Infrastructure

The belief that all things are ultimately ordered and governed by God towards a purpose. Some form of this belief features in Judaism, Islam, and Christianity, and is implied in the belief in the trustworthiness, goodness, and power of God. Human free will is not generally denied, it being claimed that God either overrules it or works through it. Providence is the capital and largest city o…

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Provincetown Players

A US theatre group (1915–29) remembered for the work of its leading playwright Eugene O'Neill and designer Robert Edmond Jones. The Provincetown Players was an amateur theater company that began in Provincetown, Massachusetts, on the tip of Cape Cod, in 1915, and is most famous for producing the plays of American playwrights, Eugene O'Neill and Susan Glaspell. The Provinc…

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Provo

40º14N 111º39W, pop (2000e) 105 200. Seat of Utah Co, NC Utah, USA; located on the R Provo, near L Utah; settled by Mormons in 1849; birthplace of Paul D Boyer and James S Coleman; railway; Brigham Young University (1875); distributing, processing and manufacturing centre in a mining and irrigated farming area. Provo was a Dutch counterculture movement in the mid-1960s that focused on p…

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provo

An abbreviation of provocation, describing the youth movement against the establishment in The Netherlands, particularly in Amsterdam, in the late 1960s. It started in 1965 and was dissolved officially in 1967; its role was taken over by the Kabouters (1969). The provos claimed responsibility for the ‘white bicycle’ plan (bicycles for ‘common use as a protest to motorized traffic’), ‘white wo…

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proxemics - Sharia

The study of how people use physical space as an aspect of non-verbal communication. It is concerned with the intimate, personal, social, and public distances that individuals, classes, and cultures maintain in their interactions with each other. Several research studies have now been made of such behaviours as how closely people sit together, how much they touch each other while talking, and how …

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Prudence Crandall

Educator and abolitionist, born in Hopkinton, Rhode Island, USA. Her short-lived attempt to train young black women as teachers in her Canterbury, CN, boarding school (1833–4) provoked the passage of a local ‘black law’, and harassment ranging from arrest to violent attacks. She worked for women's rights and temperance throughout her life. Prudence Crandall, a schoolteacher raised as a Q…

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Prudentius

Christian poet, born in Caesaraugusta, Spain. He practised as a pleader, acted as civil and criminal judge, and afterwards received high office at the imperial court. In his later years he devoted himself to the composition of religious poetry, including Cathemerinon liber, a series of 12 hymns, and Hamartigeneia, on the origin of evil. Aurelius Prudentius Clemens was a Roman Christian poet…

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Prunella (Margaret Rumney) Scales

Actress, born in Abinger, Surrey, SE England, UK. Educated in Eastbourne, she trained at the Old Vic Theatre School and the Herbert Berghof Studio, New York City. She played in repertory in various British cities, and has made numerous appearances in the West End, including Hay Fever (1968), When We Are Married (1986), and The School for Scandal (1990). On television she played opposite John Clees…

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prunus

A tree or shrub of a large temperate genus containing many well-known ornamentals and orchard fruits, such as cherry, plum, peach, and almond; flowers with five petals and usually 20 stamens; fruit a single stony seed surrounded by a fleshy outer layer. (Genus: Prunus, 400 species. Family: Rosaceae.) Prunus is a genus of trees and shrubs, including the plums, cherries, peaches, apricots and…

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Prussia - Symbols, Geography and population, Early history, Kingdom of Prussia, Napoleonic Wars, Wars of unification, German Empire

A N European state, originally centred in the E Baltic region as a duchy owing suzerainty to Poland. Prussia was inherited by the German house of Brandenburg in the early 17th-c. Brandenburg-Prussia was consolidated and expanded, and Polish sovereignty thrown off, by Frederick William the ‘Great Elector’ (1620–88). The kingdom of Prussia was founded in 1701; under Frederick William I (1713–40)…

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psaltery

A mediaeval zither, constructed in various shapes, with a wooden soundbox and strings played by the fingers or with a plectrum. It is considered the ancestor of the dulcimer, which replaced it in the 15th-c. The word psaltery was earlier used for any plucked string instrument. A psaltery is a stringed musical instrument of the harp or the zither family. The psaltery of Ancient Greece dates …

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psephology

The study of elections and voting. It is popularly associated with the analysis of voting figures and the forecasting of outcomes, but covers all aspects of elections including legal frameworks, candidate selection, sociological and geographical analysis of voting patterns, and electoral systems. Psephology is the statistical study of elections. Psephology also has various appli…

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psi

A parapsychological term for certain paranormal processes, embracing both extrasensory perception and psychokinesis. The term was introduced by British psychologist R H Thouless, being the letter of the Greek alphabet most appropriate to stand for things considered as psychic. Psi has multiple meanings: A homophone of Psi is Sai, which is an Asian weapon shaped (probably coincid…

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psittacosis - In birds, In humans

A disease caused by infection with Chlamydia psittaci. The micro-organism normally infects birds, but can be transmitted to humans in infected droppings. Alternative names for the disease are parrot fever and pigeon fancier's lung. There is a flu-like illness with pneumonia, often severe. Treatment is with the antibiotic tetracycline. In medicine (pulmonology), psittacosis -- also known as …

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psoriasis

A common persisting or recurring skin disorder, in which small red scaly itching patches form in the superficial layers of the skin. The lesions particularly affect the elbows, knees, scalp, and nails. The cause is unknown, but the turnover of the basal cells of the skin is increased. The condition causes a great deal of personal distress. It rarely threatens life, but may do so when it becomes wi…

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Psyche

In Greek mythology, ‘the soul’, usually represented by a butterfly. In the story told by Apuleius, she was beloved by Cupid, who hid her in an enchanted palace, and visited her at night, forbidding her to look at him. Her sisters persuaded her to light a lamp; she saw Cupid, but was separated from him, and given impossible tasks by Venus, who impeded her search for him. The story is an allegory …

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psychedelic art - Features of psychedelic art, Psychedelic artists

An art style that flourished in the late 1960s, influenced by the craze for hallucinatory drugs, especially LSD. Typical designs feature abstract swirls of high-key colour, sometimes accompanied by calligraphy in a curvilinear style derived from Art Nouveau. Psychedelic art refers to art that is inspired by the psychedelic experience induced by drugs such as LSD, Mescaline, and Psilocybin. …

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psychiatry - Psychiatry in professional practice, Treatment overview, Diagnostic systems of psychiatric disorders, History, Further considerations

A branch of medicine concerned with the study, diagnosis, prevention, and treatment of mental and emotional disorders. Its pattern of practice derives from many other disciplines (such as philosophy, psychology, biology, and ethology) and incorporates a wide range of treatment modalities. Within psychiatry, there is a range of sub-specialties including child psychiatry, liaison psychiatry (the stu…

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psychoanalysis - History, Technique, Theory, Modern Adaptations, Criticisms, Influence

The theory and clinical practice of a form of psychology which emphasizes unconscious aspects of the mental life of an individual. The treatment, pioneered by Freud, is a form of therapy which attempts to eliminate conflict by altering the personality in a positive way. Freud introduced ideas concerning the use of the study of dreams as a way of understanding people's deeper emotions; he emphasize…

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psychodrama - Psychological uses

A technique involving a combination of behavioural and psychoanalytic psychotherapy which makes use of the dramatic presentation of personal life situations. Through these, the patient learns new ways of dealing with both emotional and interpersonal problems. In psychodrama, participants explore internal conflicts through acting out their emotions and interpersonal interactions on stage. A …

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psychohistory - Description, Areas of Psychohistorical Study, Emergence as a Discipline, Independence as a Discipline, Psychogenic mode

A method of historical study using psychoanalytic methods, especially those of Sigmund Freud, who attempted analyses of Leonardo da Vinci and Woodrow Wilson. Its leading practitioner was Erik H Erikson (1902–94), whose Young Man Luther (1958) shocked traditional historians by connecting the reformer's theological breakthrough with an ‘identity crisis’, the result of an allegedly unhappy childho…

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psychokinesis (PK) - Origin, Grammatical forms, Measurement and observation, Notable claimants of psychokinesis or telekinesis, Belief in telekinesis

One of the two major categories of allegedly paranormal phenomena studied by parapsychologists (the other being extrasensory perception). It is defined as the influencing by a living agent of a physical system or object by means other than those currently understood by the physical sciences. The phenomenon was earlier referred to as telekinesis. Psychokinesis (< Greek τῆλε + κίνησ…

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psycholinguistics - Areas of study, Theories, Methodologies, Issues and areas of research, Bibliography/Further Reading

The study of the psychology of language. Psycholinguists are variously concerned with first and second language acquisition, language production and comprehension, and linguistic deficits such as aphasia and dyslexia. The central goal of the subject is to marry the methods and theories of the linguist with those of the psychologist. For example, a linguist might propose a grammar that accurately d…

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psychologism

The theory that philosophical problems are really questions of fact about the workings of the human mind, to be investigated by psychology. The theory was developed in the 19th-c by German philosophers. It was applied by Mill to the case of logic, but was strongly resisted by Frege and Husserl. Psychologism is a generic type of position in philosophy according to which psychology plays a ce…

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psychology - History, Principles, Scope of psychology, Research methods, Criticism, Art Psychology

The science of mental life - a succinct definition used by William James in 1890. Modern psychology began with the great advances in science and medicine of the 19th-c, including the work of Darwin on comparative studies of behaviour, Galton on inheritance and variation in human abilities, Helmholtz and others on the functions of the nervous system, Fechner on the basis of psychophysics, and Freud…

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psychometrics - Origins and background, Definition of measurement in the social sciences, Instruments and procedures, Theoretical approaches

A branch of psychology concerned with the measurement of psychological characteristics, especially intelligence, abilities, personality, and mood states. Psychometric tests are carefully constructed and standardized to provide measures of the highest possible reliability and validity. Psychometrics is the field of study concerned with the theory and technique of psychological measurement, w…

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psychometry - Depictions of psychometry in popular culture

In parapsychology, the apparent ability of a person to gain information paranormally from an inanimate object about events associated with it or its owner. In parapsychology, psychometry is an alleged psi (or psychic) ability in which the user is able to relate details about the past condition of an object or area, usually by being in close contact with it. Psychometry is a type of re…

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psychopathology - Psychopathology as the study of mental illness, Psychopathology as a descriptive term

A term used in psychiatry and clinical psychology, referring to any form of mental illness or aberration. Psychopathology is a term which refers to either Many different professions may be involved in studying mental illness or distress. The term psychopathology may also be used to denote behaviours or experiences which are indicative of mental illness, even if they …

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psychopharmacology - History, Major Drug Classes that are Studied

The science of the mechanisms, uses, and side-effects of drugs that modify psychological function and behaviour. Psychopharmacology is the study of drug-induced changes in mood, thinking, and behavior. These drugs may originate from plants, minerals, synthetic/chemical, or herbal derivatives or animal by-products. Changes in mood, thinking, and behavior may be mediated by interaction …

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psychophysics - Experimentation

Methods originated by Gustav Fechner in 1860 in an attempt to quantify, as psychophysical laws, the relationships between physical stimulation and sensations. Measures of sensitivity have been developed into rigorous techniques (eg using signal detection theory), nowadays used principally to establish and describe the constraints on perception provided by the sensory apparatus. Scaling methods, wh…

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psychosis - Classification, Causes, Signs and symptoms, Pathophysiology, Treatment

A psychiatric term with a variety of uses. It is most clearly used when referring to psychiatric illnesses in which there is a loss of contact with reality, in the form of delusions or hallucinations. Less optimally, it is an indication that a psychiatric illness is severe rather than mild or moderate in its impact on the individual. It is also used with reference to two main groups of psychiatric…

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psychosurgery - History, Legal restrictions, Neurological effect, Present day, Famous people who underwent lobotomy, Fictional examples

A procedure in which there is surgery on a brain regarded as histologically normal, with the intention of influencing the course of a behaviour disorder. The term was first employed by the US neurologist Walter Freeman (1895–1972) and US neurosurgeon James Winston Watts (1904–94) in 1942, but the procedure was first used in 1935. The intention in psychosurgery is to create a lesion in the brain …

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psychotherapy - General description, Schools and approaches, The therapeutic relationship

The treatment of emotional problems by a trained therapist, with the object of removing or modifying maladaptive feelings or behaviours and the promotion of what is referred to as ‘personal growth and development’. There are various styles of treatment, including individual psychotherapy, marital counselling, family psychotherapy, and group psychotherapy. The question of the effectiveness of psy…

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Ptah - Origin of name

An early Egyptian god associated with Memphis, and represented in human shape. Originally the creator of the world, he is later the god of craftsmanship. The name ‘Egypt’ is a Greek misunderstanding of ‘Hut-ka-Ptah’, which means ‘the mansion of Ptah’. Herodotos equated him with Hephaestus. Ptah also refers to the asteroid 5011 Ptah In Egyptian mythology, Ptah (also spelt P…

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ptarmigan

A grouse of the N hemisphere, inhabiting the high-altitude Alpine zone and tundra; moults three times a year; plumage mottled grey in summer, white in winter, with thickly feathered feet and toes acting as snowshoes. (Genus: Lagopus, 3 species.) The Ptarmigan (Lagopus muta or mutus, is a small (31–35 cm long) bird in the grouse family. …

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Ptolemy - Name, Astronomy, Geographia, Astrology, Music, Other works, Named after Ptolemy

Greek astronomer and geographer, who worked in the great library in Alexandria. Considered the greatest astronomer of late antiquity, his book known as Almagest (‘the greatest’) is the most important compendium of astronomy produced until the 16th-c. His system, an Earth-centred universe (the Ptolemaic system), held sway until dislodged by Copernicus. He also compiled a Geographia, containing a …

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Ptolemy Soter I - Successor of Alexander

Macedonian general in the army of Alexander the Great, who became ruler of Egypt after Alexander's death (323 BC). In 304 BC he adopted the royal title, and thus founded the Ptolemaic dynasty. An able ruler, he secured control over Palestine, Cyprus, and parts of Asia Minor, and placed his regime everywhere on a sound military and financial basis. In 305 BC he defended the Rhodians against Demetri…

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Ptolemy Philadelphus II - Reign, Relations with India

King of Egypt (283–246 BC), the son and successor of Ptolemy I, Soter. Under him the power of Egypt attained its greatest height. He was generally successful in his external wars, founded the Museum and Library, purchased many valuable manuscripts of Greek literature, and attracted leading Greek intellectuals to his court. The Egyptian history of Manetho was dedicated to him, but the story that h…

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puberty - The physical changes of puberty in girls, The physical changes of puberty in boys

The period of change from childhood to adulthood, characterized by the attainment of sexual maturity and full reproductive capacity. It begins earlier in girls (about age 11) than in boys (about age 13), and lasts between 3 and 5 years. Its onset depends on both genetic and environmental influences (such as nutritional status). In both sexes there is an accelerated growth of the body (the adolesce…

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public house - Overview of pubs

In the UK, an establishment licensed to sell alcoholic drinks; the ‘pub’ is, like the café in Europe, a place to meet and relax. Many pubs have names of great antiquity, often of historical interest; the common image of the pub is of a quaint building in the country, dating from Tudor times (or earlier), but many different forms exist, and true ‘traditional’ pubs are becoming rarer. A …

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Public Record Office (PRO) - History, Merger with the Historical Manuscripts Commission

The British national depository of government papers, selected archives, and legal documents to be permanently preserved, spanning 1000 years. Its holdings include Magna Carta, Domesday Book, and Shakespeare's will. It was established by Act of Parliament in 1838. Formerly based in Chancery Lane, C London, its headquarters is now at Kew, Surrey, with a Family Records Centre also in C London. …

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public relations (PR) - Definition, History, The industry today, Methods, tools and tactics, Politics and civil society

The practice of managing reputation and of building goodwill on behalf of organizations, both externally and internally. It developed as a management and, later, academic discipline in the USA and in the UK in the early 20th-c, but is now practised worldwide in the commercial and public sectors. PR is commonly associated with ploys to ensure positive media coverage. In reality, public relations to…

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public school - United Kingdom, Europe (EU), South Asia

In England, a fee-paying school for pupils of secondary age, often over 11 for girls and over 13 for boys; famous examples include Charterhouse, Eton, Harrow, Merchant Taylors', Radley, Roedean, Rugby, and Westminster. In the USA, it is the exact opposite: a school run by public authorities where fees are not paid. In many English-speaking nations , a public school is a school that is finan…

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public sector

The parts of an economy owned by government. This includes both central and local government, and intermediate levels such as states of the USA, or Länder in Germany. It also includes public corporations operating state-owned industries, such as coal-mines or railways. The public sector is the part of economic and administrative life that deals with the delivery of goods and services by an…

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public sector borrowing requirement (PSBR)

The amount of money a government needs to raise in a fiscal year by borrowing. The need arises from tax revenues and other income being less than total spending of the various government departments. The budget deficit has to be borrowed. This is normal in the UK, though general economic growth and the sale of government-owned enterprises led to budget surpluses in the late 1980s. In the USA the F…

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public switched telephone network (PSTN) - Architecture and context, Digital Channel, U.S. Telephone Switch Hierarchy

The conventional telephone network provided by the Posts, Telegraph and Telephones Authorities for normal voice communication, often referred to today as POTS (Plain Old Telephone Service). It is of particular interest to computer specialists since, by using modems, data communication between computers can be effected over a public telephone line. The line is in use, and has to be paid for, for th…

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publishing - The process of publishing, Publishing as a business, Academic publishing, Tie-in publishing

The complex commercial activity in which a publisher selects, edits, and designs verbal and illustrative material, arranges its manufacture, and offers it for sale. The commodity in which publishers trade is information, interpreted widely to include entertainment, verbal and visual art, and propaganda. The media employed for publication embrace books, periodicals, newspapers, television and radio…

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Publius Cornelius Dolabella

Roman politician and Cicero's profligate son-in-law. Having obtained the tribuneship (47 BC), he brought forward a bill cancelling all debts, which led to bloody struggles in Rome. On Caesar's murder (44 BC) he usurped the consulate, and obtained the province of Syria. He proceeded to wring money from the towns of Asia with a recklessness that brought about his outlawry. Laodicea, in which he had …

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Pud Galvin - Trivia

Baseball pitcher, born in St Louis, Missouri, USA. One of the game's great pioneers, the stocky right-hander won 361 games during his 14-year career (1879–92), mostly with Buffalo and Pittsburgh. He was elected to baseball's Hall of Fame in 1965. James Francis "Pud" Galvin (December 25, 1856 – March 7, 1902), an American professional baseball pitcher, was Major League Baseball's first 30…

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Puebla

19°03N 98°10W, pop (2000e) 1 269 000. Capital of Puebla state, SC Mexico; SE of Mexico City; altitude 2150 m/7054 ft; damaged by earthquake, 1973; railway; two universities (1937, 1940); agricultural trade, textiles, pottery, cement, onyx; famous for its glazed tiles which cover the domes of many of its 60 churches; cathedral (17th-c), Church of Santo Domingo (1659), archbishop's palace (16…

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Pueblo (Indians) - Colonial history, Historic places, Beliefs

North American Indians of SW USA, living in settlements called pueblos in multi-storied, permanent houses made of clay. Culturally and linguistically diverse, they are divided into E and W Pueblo, the latter including the Hopi and Zuni. They are famed for their weaving, basketry, sand paintings, and pottery, and have preserved much of their traditional culture intact. Pueblos are traditiona…

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puerperal fever - History

A fever greater than 38°C arising in a mother in the first 14 days after childbirth. It may be a consequence of genital, breast, or urinary tract infection. It was formerly a serious complication of childbearing, when infection was introduced to the genital tract by the hands of doctors or midwives. Today it is a rare cause of maternal death. Puerperal fever, also called childbed fever, is…

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Puerto Rico - History, Geography, Geology, Demographics, Politics, Administrative divisions, Economy, Culture, Sports, Transportation

(USA Formal Dependencies) The Commonwealth of Puerto Rico, (Spanish: Estado Libre Asociado de Puerto Rico, IPA [esˈtaðo ˈlibɾe asoˈsjaðo de ˈpweɾto ˈriko]), also Porto Rico (archaic) and more commonly Puerto Rico, is a United States territory with Commonwealth status located in the northeastern Caribbean, east of the Dominican Republic and west of the Virgin Islands. The …

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puffball - Habitat and structure, Edibility and identification, Classification

A globular, often spherical fruiting body of certain fungi (the Gasteromycetes); found above ground; spores released when the wall of the puffball ruptures. (Subdivision: Basidiomycetes. Order: Lycoperdales.) A puffball is a member of any of a number of groups of fungus in the division Basidiomycota. The puffballs were previously treated as a taxonomic group called the Gasteromycetes or …

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puffin - Species

Any of four species of auk of the genus Fratercula (2 species), Cerorhinca (1 species), or Lunda (1 species); bill large, deep, multicoloured; eats young fish and sand eels; nests in burrows or rock crevices. Cerorhinca is nocturnal. The common name puffin describes any of three auk species (or alcids) in the bird genus Fratercula (Latin: little brother - probably a reference to their black…

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pug - Appearance, Temperament, Health, Gallery

A toy breed of dog developed in China; similar origins to the Pekinese, but with a short coat; now taller and heavier than the Pekinese, but face still flat, and tail carried over back. A Pug is a toy dog breed of dog with a wrinkly face, and medium-small body. Or, in nod to the breed's sometimes mischievous nature, from the character "Puck" of A Midsummer Night's Dream. T…

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Pula - Population, Geography, Sights, History, Culture, Economy, Tourism, Transport, Nearby towns and villages

44°52N 13°52E, pop (2000e) 60 100. Seaport and resort town in W Croatia, on the Adriatic coast; built on the site of a former Roman colony; airport; railway; car ferries to Italy; naval and commercial port, shipyards, tourism; Roman amphitheatre, Temple of Augustus, cathedral, castle (17th-c); folk displays and concerts (Jun–Aug), film festival (Jul–Aug). Pula (Croatian Pula, Italian …

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Pulaski

35º19N 87º03W, pop (2000e) 7900. County seat of Giles Co, Tennessee, USA; birthplace of Walter Beech and John Crowe Ransom; Ku Klux Klan founded here (1866); Brown-Daly-Norne House (1869), Sam Davis Museum, Neoclassical county courthouse (1909); Milky Way Farm (built by the Mars Candy Co in 1932) is open to the public. Pulaski can refer to: People: Towns in the Un…

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puli

A medium-sized breed of dog developed in Hungary for hunting and as a sheepdog; ears pendulous; tail curls over back; coat thick and long, covering eyes and ears, often reaching the ground and tangled into rope-like cords. The Puli is a medium-small breed of dog known for its long, corded coat. …

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