education. Until the end of the Cold War, the field of political philoso¬ phy was characterized by a division between Marxists and more tradi¬ tional liberal thinkers, as well as by disagreements between left- and right-leaning liberals, such as John Rawls and Robert Nozick (1938— 2002), respectively. From the 1970s, feminist political philosophy drew attention to the apparent gendered nature of many concepts and problems in Western political philosophy, especially autonomy, rights, liberty, and the public-private distinction.
political science Academic discipline concerned with the empirical study of government and politics. Political scientists have investigated the nature of states, the functions performed by governments, voter behaviour, political parties, political culture, political economy, and public opinion, among other topics. Though it has roots in the political philosophies of Plato and Aristotle, political science in the modern sense did not begin until the 19th century, when many of the social sciences were established. Its empirical and generally scientific orientation is traceable to the work of Henri de Saint-Simon and Auguste Comte. The first institution dedicated to its study, the Free School of Political Science, was founded in Paris in 1871.
polka Lively couple dance of Bohemian folk origin. The polka (Czech for “Polish woman”) is characterized by three quick steps and a hop and is danced to music in 2 A, or duple, time. It originated in the early 19th century and became popular in ballrooms across Europe and in North and South America. It has remained popular into the 21st century as both a folk dance and a ballroom dance.
poll tax Tax of a uniform amount levied on each individual. The most famous British poll tax was the one levied in 1380, a main cause of the 1381 Peasants' Revolt. In the U.S., poll taxes were used as a voting pre¬ requisite in the southern states; when payment was made a prerequisite to voting, impoverished blacks (and often poor whites) were effectively denied the vote. In 1966 the U.S. Supreme Court ruled that states could not levy a poll tax as a prerequisite for voting in state and local elections.
pollack or pollock Vpa-tak\ Either of two commercially important North Atlantic species of food fish in the COD family (Gadidae). Pollachius (or Gadus) virens, called saithe or coalfish in Europe, is deep green with a pale belly. It has a small chin barbel (fleshy protuberance) and three dorsal and two anal fins. A carnivorous, lively, usually schooling fish, it grows to about 3.5 ft (1.1 m) long and weighs up to 35 lbs (16 kg). The other species, Theragra chalcogramma, or walleye pollack, closely resembles P. virens.
1795, Mecklenburg county, N.C.,
Polk, James K(nox) (b. Nov. 2,
U.S.—d. June 15, 1849, Nashville,
Tenn.) 11th president of the U.S.
(1845-49). He was a friend and sup¬ porter of Andrew Jackson, who helped Polk win election to the U.S.
House of Representatives in 1825.
He left the House in 1839 to become governor of Tennessee. At the dead¬ locked 1844 Democratic Party con¬ vention Polk was nominated as the compromise candidate; he is consid¬ ered the first dark-horse presidential candidate. A proponent of western expansion, he openly laid claim to the whole territory that extended as far north as latitude 54° 40’ with the slogan “Fifty-four Forty or Fight”
(see Oregon Question). Elected at the age of 49, the youngest president to that time, he successfully con¬ cluded the Oregon border dispute with Britain (1846) and secured pas- sage of the Walker Tariff Act (1846),
which lowered import duties and helped foreign trade. He led the pros¬ ecution of the Mexican War, which resulted in large territorial gains but reopened debate over the extension of slavery. His administration also established the Department of the Interior, the U.S. Naval Academy, and the Smithsonian Institution; oversaw revision of the treasury system; and proclaimed the validity of the Monroe Doctrine. Though an efficient and competent president and deft in his handling of Congress, he was exhausted by his efforts and did not seek reelection; he died three months after leaving office.
James K. Polk, daguerreotype by Mathew Brady, 1849.
LIBRARY OF CONGRESS, WASHINGTON, D.C.
© 2006 Encyclopaedia Britannica, Inc.
1522 I Pollaiuolo ► polonaise
Pollaiuolo \ I pol-ll-'w6-lo\ # Antonio and Piero del orig. Anto¬ nio and Piero di Jacopo d'Antonio Benci (respectively b. Jan. 17, 1432/33, Florence, Republic of Florence—d. Feb. 4, 1498, Rome; b. 1443, Florence—d. 1496, Rome) Italian sculptors, painters, engravers, and goldsmiths. Antonio probably trained in goldsmithing and metalwork¬ ing with Lorenzo Ghiberti, while Piero may have studied painting with Andrea del Castagno. The brothers collaborated consistently after 1460, producing their works under a combined signature, and their individual contributions are hard to determine. Antonio is recognized as a superb draftsman and was among the first to practice anatomical dissection in the study of the human form; Piero’s individual work is less artistically sig¬ nificant. In Florence they created an altarpiece in San Miniato al Monte and The Martyrdom of St. Sebastian (1475) in the Pucci Chapel of the Church of the Santissima Annunziata. In Rome their works included the tombs of Popes Sixtus IV and Innocent VIII. Antonio’s famous Battle of Nudes is one of the largest and most important Italian engravings of the 15 th century.
pollen Mass of microscopic spores in a seed plant that appears usually as a fine dust. Each pollen grain is tiny, varies in shape and structure, is formed in the stamens in seed plants, and is transported by various means (see pollination) to the pistil, where fertilization occurs. The outer layer of a pollen grain is very resistant to disintegration; treatment with intense heat, strong acids, or strong bases has little effect on it. Because the grains often are very distinctive, some plant species may be identified by their pollen grains alone. Common components of both recent and ancient geo¬ logic sediments, pollen grains have provided much information on the origin and geologic history of plant life on land. Pollen is produced in such quantities that it is a significant part of the airborne components of earth’s atmosphere. The protein-containing substance in many pollen grains (e.g., ragweed and many grasses) causes the allergic reaction com¬ monly known as hay fever.
pollination Transfer of pollen grains in seed plants from the stamens, where they form, to the pistil. Pollination is required for fertilization and the production of seeds. On the surface of the pistil the pollen grains ger¬ minate (see germination) and form pollen tubes that grow downward toward the ovules. During fertilization, a sperm cell in a pollen tube fuses with the egg cell of an ovule, giving rise to the plant embryo. The ovule then grows into a seed. Since the pollen-bearing parts of the stamens are rarely in direct contact with the pistil, plants commonly rely on external agents for pollen transport. Insects (especially bees) and wind are the most important pollinators; other agents include birds and a few mammals (notably certain bats). Water transport of pollen is rare. An egg may be fertilized by self-pollination (when the sperm comes from pollen produced by the same flower or by another flower on the same plant) or by cross¬ pollination (when the sperm comes from the pollen of a different plant).