Mount Coroa
NATIONAL Viana do Castelo-
MONTEZINHO .NATURE PARK
Povoa de Varzim. Vila do Conde
Estrela * 6,532:^
SERRADAI NATURE P fi
SPAIN
Coimbra
ESTRELA
Leiria ' \ (LS A
Batalna^* Fatim#, ' I,-A
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3 Porttflegre
Santarem
^Lisbon Estrpmoz ,»*Barreiro Evora
SERRADESAO MAMEDE NATURE PARK
Cape
Carvoeiro
:hel SetSbal J
Setubal rs
Bayl'g
Sines* ^
N-Alqueua |j? Reservoir
Portimao* Faro t Cape
Saint Vincent
Gulf of Cddiz\{f
© 2002 Encyclopaedia Britannica, Inc.
ATLANTIC
OCEAN
people are Portuguese. Language: Portu¬ guese (official). Religion: Christianity (predominantly Roman Catholic). Cur¬ rency: euro. Administratively, the Atlantic islands of the Azores and Madeira are part of Portugal. Portugal is divided roughly in half by the Tagus River; the highlands rise mostly north of the Tagus and stretch northeast into Spain. Portugal has an industrialized economy in which both public and private sectors participate. Major industries were nationalized after a military coup in 1974, but many were returned to the private sector beginning in the late 1980s. Although motor vehicle manufacture is significant, light industries predominate; important products include textiles and clothing, paper and wood products, and chemicals. Portugal is a republic with a unicameral legislature; the chief of state is the president, and the head of government is the prime minister. In the 1st millennium bc, Celtic peoples settled the Iberian Peninsula. They were conquered c. 140 bc by the Romans, who ruled until the 5th century ad, when the area was invaded by Germanic tribes. A Muslim invasion in 711 left only the northern part
PORTUGAL
of Portugal in Christian hands. In 1179 it became the kingdom of Portu¬ gal and expanded as it reconquered the Muslim-held sectors. The bound¬ aries of modern continental Portugal were completed under King Afonso III (reigned 1248-79). From 1580 to 1640 Portugal was united with Spain. In the 15th and 16th centuries the monarchy encouraged exploration that took Portuguese navigators to Africa, India, Indonesia, China, the Middle East, and South America. Although Portugal established several colonies, they achieved independence over the years (see Brazil; Goa; Cape Verde; East Timor; Angola; Guinea-Bissau; Mozambique; Macau). Antonio de Oliveira Salazar ruled Portugal as a dictator from 1932 to 1968. The coun¬ try’s dictatorship was overthrown in the April 25, 1974, Revolution of the Carnations. A new constitution was adopted in 1976, and civilian rule resumed. Portugal was a charter member of NATO and is a member of the European Union (EU). In 1999 the government adopted the euro as the country’s official monetary unit and returned Macau, its last overseas ter¬ ritory, to Chinese rule.
Portuguese East Africa See Mozambique Portuguese Guinea See Guinea-Bissau
Portuguese language Romance language spoken by about 170 mil¬ lion people in Portugal, Brazil, and other former Portuguese colonies. The first literary works in Portuguese date from the 13th—14th century. Stan¬ dard Portuguese is based on the dialect of Lisbon. Dialectal variation in Portugal is limited, but the differences between Brazilian and European Portuguese are more extensive, including changes in phonology, verb conjugation, and syntax. The four major dialect groups are Northern (Gali¬ cian, spoken in northwestern Spain), Central, Southern (including the Lisbon dialect), and Insular (including Brazilian and Madeiran) Portu¬ guese.
Portuguese man-of-war Any of various floating, warm-water marine cnidarians (genus Physalia, class Hydrozoa) found worldwide but mostly in the Gulf Stream and the Indian and Pacific oceans. The medusa- form body consists of a translucent, jellylike, gas-filled float, which may be 3-12 in. (9-30 cm) long. Polyps beneath the float bear hanging ten¬ tacles up to 165 ft (50 m) long. Nematocysts on some polyps paralyze fish and other prey. Other polyps then attach to, spread over, and digest the victim. A third type of polyp is involved in reproduction. The painful sting of Physalia can cause fever, shock, or disruption of heart and lung function.
Portuguese West Africa See Angola
Poseidon \po-'sI-d3n\ Greek god of water and the sea, son of Cronus and Rhea. His brothers were Zeus and Hades. When the three brothers deposed their father, the kingdom of the sea fell by lot to Poseidon.
Unpredictable and sometimes vio¬ lent, he was also god of earthquakes, and he was closely associated with horses. Most of his offspring were giants and savage creatures. By Medusa he was the father of the winged horse Pegasus. The Isthmian Games were held in his honor. In art he was often shown holding a trident and accompanied by a dolphin and tuna. The Romans identified him with Neptune.
Posen See Poznan
positivism Any philosophical sys¬ tem that confines itself to the data of experience, excludes A priori or meta¬ physical speculations, and empha¬ sizes the achievements of science.
Positivism is closely connected with EMPIRICISM, PRAGMATISM, and LOGICAL positivism. More narrowly, the term designates the philosophy of Auguste Comte, who held that human thought had passed inevitably through a theological stage into a metaphysical stage and was passing into a positive, or scientific, stage. Believing that the religious impulse would survive the decay of revealed religion, he projected a worship of mankind, with churches, calendar, and hierarchy.
Poseidon, marble statue from Melos, 2nd century bc; in the National Archaeological Museum, Athens.
AUNARI-ART RESOURCE/EB INC.
© 2006 Encyclopaedia Britannica, Inc.
1534 I positron ► postmodernism
positron Vpa-z3-,tran\ Subatomic particle having the same mass as an electron but with an electric charge of+1 (an electron has a charge of -1). It constitutes the antiparticle (see antimatter) of an electron. The existence of the positron was a consequence of the electron theory of P. A. M. Dirac (1928), and the particle was discovered in cosmic rays by Carl D. Ander¬ son (1905-1991) in 1932. Though they are stable in a vacuum, positrons react quickly with the electrons of ordinary matter, producing gamma rays by the process of annihilation. They are emitted in positive beta decay of proton-rich radioactive nuclei and are formed in pair production.
positron emission tomography (PET) Imaging technique used in diagnosis and biomedical research. A chemical compound labeled with a radioactive isotope (see radioactivity) that emits positrons is injected into the body, and detectors measure their activity in the tissues as they com¬ bine with electrons and are annihilated. Computers analyze, integrate, and reconstruct the data to produce images of the organs scanned. PET is par¬ ticularly useful for studying brain and heart functions.
possession, adverse See adverse possession
possible world Conception of a total way the universe might have been. It is often contrasted with the way things actually are. In his Theod¬ icy (1710), G.W. Leibniz used the concept of a possible world in his pro¬ posed solution to the theological problem of the existence of evil, arguing that an all-perfect God would actualize the best of all possible worlds; this idea was later satirized by Voltaire in his comic novel Candide (1759). Philosophers have since constructed several different formalizations of the concept of a possible world.
possum or phalanger \f3-Tan-jor, 'fa-.lan-jarX Any of several species (family Phalangeridae) of nocturnal, arboreal marsupials of Australia and New Guinea. They are 22-50 in. (55-125 cm) long, including the long prehensile tail, and have woolly fur. All species eat fruits, leaves, and blossoms; some also eat insects and small vertebrates. Possums grasp branches with their hind feet. Most species bear their young in tree hol¬ lows and unused birds’ nests; a few build leafy nests. Several species are endangered because of predation, fur trapping, or habitat loss, but the common brush-tailed possum is considered a pest. See also opossum.