Polaroid Corp. Major U.S. manufacturer of photographic equipment and supplies. The company was established as Land-Wheelwright Labo¬ ratories in 1932 by Edwin Land and George Wheelwright to produce Land’s first invention, an inexpensive plastic-sheet light polarizer (see polarization). By 1936 Land was using polarized material in sunglasses and other optical devices, and in 1937 the company was incorporated under the Polaroid name. After World War II Land invented the first instant camera, marketed in 1947 as the Polaroid Land camera, which delivered a finished sepia-toned print 60 seconds after exposure. The com¬ pany introduced colour film for its Polaroid cameras in the 1960s and instant motion pictures in 1977. Other Polaroid products include film, digital cameras, and identification systems.
Pole, Reginald (b. March 3, 1500, Stourton Castle, Staffordshire, Eng.—d. Nov. 17, 1558, London) English Catholic prelate. A cousin of Henry VII, Pole was sent by Henry VIII to study in Italy (1521-27) and given minor offices in the church. Critical of Henry’s antipapal policies, he wrote In Defense of Ecclesiastical Unity (1536) to defend the pope’s spiritual authority. As cardinal, he was sent by Pope Paul III on missions to persuade Catholic monarchs to depose Henry. These efforts angered Henry, who executed Pole’s brother, Lord Montague (1538), and his mother, Margaret, countess of Salisbury (1541). Pole was named papal governor of the Patrimony of St. Peter and later was presiding legate at the Council of Trent. When the Catholic Mary Tudor became queen as Mary I in 1553, he was appointed legate for England; there he instituted church reforms and was a strong influence on the queen. He was appointed archbishop of Canterbury (1556), but a conflict between the papacy and England’s ally Spain caused the pope to cancel Pole’s authority and declare him a heretic. Demoralized, he died 12 hours after the death of Queen Mary.
pole construction Method of building that dates back to the Stone Age. Excavations in Europe show rings of stones that may have braced huts made of wooden poles or weighted down the walls of tents made of animal skins supported by central poles. Two types of Native American pole structures were the wigwam and longhouse. Pole-and-thatch dwell¬ ings are common in the Caribbean, Mesoamerica, and the Pacific Islands; bamboo-pole dwellings constructed on piles are found in many wet areas of Asia. A southern African method utilizes a ring of poles that is inserted into the ground, brought together in a crest, and expertly thatched. Today, pole construction employs a vertical structure of pressure-treated wood poles firmly embedded in the ground as a pier foundation. See also tent STRUCTURE.
pole vault Track-and-field event consisting of a vault for height over a crossbar with the aid of a long pole. It became a competitive sport in the mid-19th century and was included in the first modem Olympic Games.
Polar bear (Ursus maritimus)
FRANCOIS GOHIER/ARDEA LONDON
© 2006 Encyclopaedia Britannica, Inc.
1520 I polecat ► political action committee
In competition, each vaulter is given three chances to clear a specific height. The bar is raised progressively until a winner emerges.
polecat Any of several carnivores of the weasel family (Mustelidae), found in Eurasia and Africa. The polecat hunts at night, principally on the ground, feeding on small mammals, birds, reptiles, frogs, fishes, and eggs. Species differ in size and colour. The European, or common, polecat (Mustela putorius), also called foul marten for its odour, weighs 1-3 lb (0.5-1.4 kg) and is 14-21 in. (35-53 cm) long, excluding the 5-8-in. (13- 20-cm) bushy tail. Its long, coarse fur is brown above, black below. In the U.S., skunks are often called polecats. See also ferret.
European polecat (Mustela putorius)
RUSS KINNE-PHOTO RESEARCHERS
police Body of agents organized to maintain civil order and public safety, enforce the law, and investigate crime. Characteristics common to most police forces include a quasi-military organization, a uniformed patrol and traffic-control force, plainclothes divisions for criminal investigations, and a set of enforcement priorities that reflects the community’s way of life. Administration may be centralized at the national level downward, or decentralized, with local police forces largely autonomous. Recruits usu¬ ally receive specialized training and take an exam. The modem metro¬ politan police force began with Sir Robert Peel in Britain c. 1829. Secret police are often separate, clandestine organizations established by national governments to maintain political and social orthodoxy, which typically operate with little or no restraint.
police power Power of a government to exercise reasonable control over people and property within its jurisdiction in the interest of general security, health, safety, morals, and welfare. It is generally regarded as one of the powers reserved to the states under the U.S. Constitution. In considering cases involving the exercise of police power, the courts have applied a doctrine called “balance of interests” to determine when the public’s right to health and well-being outweighs private or individual concerns. Of equal concern is that due process of law be observed.
poliomyelitis N.po-le-o-.ml-a-'lI-tosV or polio or infantile paraly¬ sis Acute infectious viral disease that can cause flaccid paralysis of muscles. Severe epidemics killed or paralyzed many people, mostly chil¬ dren and young adults, until the 1960s, when Jonas Salk’s injectable killed vaccine and Albert B. Sabin’s oral attenuated live vaccine controlled polio in the developed world. Flulike symptoms with diarrhea may progress to back and limb pain, muscle tenderness, and stiff neck. Destruction of spi¬ nal cord motor cells causes paralysis, ranging from transient weakness to complete, permanent paralysis, in fewer than 20% of patients. Patients may lose the ability to use their limbs, to breathe, or to swallow and speak. They may need physical medicine and rehabilitation, mechanical breathing assistance, or tracheal suction to remove secretions. A “postpolio syn¬ drome” occurs decades later in some cases, with weakness of muscles that had recovered.
polis Vpa-l9s\ In ancient Greece, an independent city and its surround¬ ing region under a unified government. A polis might originate from the natural divisions of mountains and sea and from local tribal and cult divi¬ sions. Usually the town was walled and contained a citadel on raised ground (acropolis) and a marketplace (agora). Government was centred in the town; usually there was an assembly of citizens, a council, and magistrates. Ideally, all citizens participated in the government and in the cults, as well as in defense and economy. Women, minors, metics, and
slaves were not citizens. Hellenism spread many of the institutions into the Middle East. See also Athens; city-state; Sparta; Thebes.
Polisario N.po-li-'sa-re-oX officially Popular Front for the Libera¬ tion of Saguia el Hamra and Rio de Oro Sahrawi political and military group. Initially an insurgent against Spanish control of Western Sahara, it turned to agitation against Morocco and Mauritania when the Spanish withdrew in 1976 and those two countries partitioned the coun¬ try. Mauritania made peace with the group in 1979, whereupon Morocco annexed the whole territory. Polisario continued its resistance, mostly from bases in Algeria. In 1991 it agreed to a ceasefire and a referendum, which has been repeatedly postponed by Morocco, to determine the state’s fate. See also Saharan Arab Democratic Republic.
Polish Corridor Strip of land that gave Poland access to the Baltic Sea. Transferred to the newly constituted state of Poland as part of the Treaty of Versailles (1919), the corridor, 20 to 70 mi (30 to 110 km) wide, separated eastern Prussia from the main part of Germany. The Germans resented the transfer, though the region had been historically Polish before the partitions of Poland and was inhabited by a Polish majority. When Poland refused to accede to Adolf Hitler’s demands for extraterritorial highways across the corridor and cession of the free port city of Danzig (Gdansk), Germany seized the pretext to invade Poland (1939), beginning World War II.