Aratus of Sicyon \3-'ra-t9s...'sis-e- 1 an\ (b. 271—d. 213 bc) Hellenis¬ tic Greek statesman, diplomat, and soldier. He democratized Sicyon (251) and, as leader of the Achaean League (in alternate years from 245), set up democracies in league cities and helped free Athens from Macedonia (229). Under him, the league opposed Sparta; with Macedonian help, it defeated Aetolia (217). Aratus nevertheless defied the anti-Roman policy of Philip V of Macedonia; his death, popularly linked to Philip, was more likely caused by tuberculosis.
Araucanian Va-.raii-'ka-ne-onzV South American Indian people who are now concentrated in the valleys and basins between the Bio Bio and Tolten rivers in south-central Chile. When the Spanish cONQUiSTADORes arrived in Chile, they encountered three Araucanian populations: the Picunche, who were accustomed to Inca control; the Huilliche, who were too few and scattered to resist the conquistadores; and the Mapuche, successful farm¬ ers and artisans. The first two were soon assimilated, but the Mapuche managed to resist Spanish and Chilean control for some 350 years. They were subdued in the late 19th century and were settled on reservations; they now live independently.
araucaria \ l ar-o- , kar-e-9\ Any pinelike coniferous plant (see conifer) of the genus Araucaria (family Araucariaceae). Found in South America, the Phoenix Islands, and Australia, araucaria trees are magnificent ever¬ greens, with whorled branches and stiff, flattened, pointed leaves. Com¬ mon species are the monkey puzzle tree and the Norfolk Island pine, often grown as a houseplant. Several species are cultivated on the Pacific coast of the U.S. and in southern Florida. See also pine.
Arawak \'ar-3-,wak\ American Indians of the Greater Antilles and South America. The Taino, an Arawak subgroup, were the first native peoples encountered by Christopher Columbus on Hispaniola. The island Arawak were wiped out by disease, but some mainland South American Arawak, who inhabited northern and western areas of the Amazon River basin, sur¬ vived conquest. At the turn of the 21st century, the Arawak lived mainly in Guyana, where they represented about one-third of the Indian population. Smaller numbers live in Suriname, French Guiana, and Venezuela.
Arawakan \,ar-3-'wa-k3n\ languages or Maipuran \ml-'pu-r9n\ languages Largest family of American Indian languages. The family comprises an estimated 65 known languages, of which at least 30 are now extinct. They stretch from the Caribbean coast of Central America to the Gran Chaco and southern Brazil, and from western Peru to the Guianas and central Brazil. Taino, a now-extinct Arawakan language of the Antil¬ les, was the first American Indian language encountered by Europeans. Arawakan languages that are still viable include Goajiro in Colombia and Venezuela; Amuesha, Machiguenga, and the Campa languages in Peru; and Terena in Brazil.
Arbenz \'ar-bans\ (Guzman), Jacobo (b. Sept. 14, 1913, Quezalt- enango, Guat.—d. Jan. 27, 1971, Mexico City, Mex.) Soldier and presi¬ dent of Guatemala (1951-54). The son of a Swiss emigre, Arbenz joined the leftist army officers who overthrew the dictator Jorge Ubico (1878— 1946) in 1944. Elected president in 1951, he made land reform his cen¬ tral project. His efforts to expropriate idle land owned by the United Fruit Co. and his alleged communist links led to an invasion sponsored by the U.S. Central Intelligence Agency. When the army refused to defend Arbenz against what appeared to be a superior force, he resigned and went into exile, and the CIA installed the leader of the proxy army. Col. Carlos Castillo Armas (1914-57), as president.
Arber, Werner (b. June 3, 1929, Granichen, Switz.) Swiss microbi¬ ologist. He has taught chiefly at the University of Basel. He shared a 1978 Nobel Prize with Daniel Nathans and Hamilton O. Smith for the discovery and use of restriction enzymes that break the giant molecules of DNA into pieces small enough to be separated for individual study but large enough to retain meaningful amounts of the genetic information of the original substance. He also observed that bacteriophages cause mutation in their bacterial hosts and undergo hereditary mutations themselves.
Arbiter, Gaius Petronius See Gaius Petronius Arbiter
arbitrage Var-bo-.trazhX Business operation involving the purchase of foreign currency, gold, financial securities, or commodities in one market and their almost simultaneous sale in another market, in order to profit
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from price differentials existing between the markets. In the 1980s a form of speculation called risk arbitrage arose, in which speculators tried to identify companies targeted for takeover and buy blocks of their stock, to be resold at a profit when the takeover was announced and the compa¬ ny’s stock rose in value. See also insider trading; security.
arbitration Process of resolving a dispute or a grievance outside a court system by presenting it for decision to an impartial third party. Both sides in the dispute usually must agree in advance to the choice of arbitrator and certify that they will abide by the arbitrator’s decision. In medieval Europe arbitration was used to settle disputes between merchants; it is now commonly used in commercial, labour-management, and interna¬ tional disputes. The procedures differ from those used in the courts, espe¬ cially regarding burden of proof and presentation of evidence. Arbitration avoids costly litigation and offers a relatively speedy resolution as well as privacy for the disputants. The main disadvantage is that setting guide¬ lines is difficult; therefore the outcome is often less predictable than a court decision. See also mediation.
arbor Garden shelter providing privacy and partial protection from the weather, most commonly a lightweight, latticed framework (trellis) of wood or metal with interlaced branches of vines or climbing shrubs trained over it. If there is a distinction between an arbor and a bower, it is that the bower is an entirely natural recess whereas an arbor is only partially natural.
arboretum X.ar-bo-'re-tomV Place where trees, shrubs, and sometimes herbaceous plants are cultivated for scientific and educational purposes. An arboretum may be a collection in its own right or a part of a botanical garden. Important U.S. arboretums include the Arnold Arboretum of Har¬ vard University (Jamaica Plain, Mass.) and the U.S. National Arboretum in Washington, D.C.
arboriculture Var-bor-o-.kol-choA Cultivation of trees, shrubs, and woody plants for shading and decorating. Arboriculture includes all aspects of growing, maintaining, and identifying plants, arranging plant¬ ings for their ornamental values, and removing trees. The well-being of individual plants is the major concern of arboriculture, in contrast to such related fields as forestry and agriculture, in which the major concern is the welfare of a large group of plants as a whole.
arborvitae \,ar-b9r-'vl-te\ (Latin: “tree of life”) Any of six species (genus Thuja) of resinous, evergreen ornamental and timber conifers of the cypress family, native to North America and eastern Asia. Arborvitae trees or shrubs have thin, scaling outer bark and fibrous inner bark; hori¬ zontal or ascending branches; and flattened, spraylike branchlets with scalelike leaves. The Oriental, or Chinese, arborvitae ( T. orientalis ), a popular ornamental native to Asia, is a gracefully symmetrical shrub. Arborvitae wood is soft and lightweight but very durable, fragrant, and easily worked. The giant arborvitae ( T. plicata) is the most important timber-producing species, but the wood of the American arborvitae ( T. occidentalis) is also frequently used. False arborvitae ( Thujopsis dola- brata) is closely related.
arbovirus X.ar-bo-'vI-rosX Any of a large group of viruses that develop in arthropods (chiefly mosquitoes and ticks). The name derives from “arthropod-borne virus.” The spheroidal virus particle is encased in a fatty membrane and contains RNA; it causes no apparent harm to the arthro¬ pod host. Arboviruses are transmitted by bites to vertebrate hosts, in which they establish infections and complete their growth cycle; they include the agents responsible for yellow fever and equine encephalitis. See also TOGAVIRUS.