curl v = /1
0v 3
dtj
d.v I
dvi \
By /
in which v is the vector field (v 3 , v 2 , v 3 ), and v lf v 2 , v 3 are functions of the variables x, y, and z, and i, j, and k are unit vectors in the positive x, y, and z directions, respectively. In fluid mechanics, the curl of the fluid velocity field (i.e., vector velocity field of the fluid itself) is called the vorticity or the rotation because it measures the field’s degree of rotation around a given point.
curlew Any of eight species (genus Numenius) of shorebirds having a sickle-shaped bill that curves downward at the tip, a streaked, gray or brown body, and a long neck and legs. Curlews breed inland in temper¬ ate and subarctic regions of the Northern Hemisphere and migrate far south. They eat insects and seeds during migration but feed on worms and fiddler crabs while wintering on marshes and coastal mudflats. The east¬ ern curlew is the largest species (24 in., or 60 cm, long); the common, or Eurasian, curlew, almost as large, is the largest European shorebird. The Eskimo curlew is now virtually extinct.
Curley, James Michael (b. Nov. 20, 1874, Boston, Mass., U.S.—d. Nov. 12, 1958, Boston) U.S. politician. He served in the U.S. House of Representatives (1911-14). As Boston’s mayor (1914-18, 1922-26, 1930-34, 1947-50), he dominated the city’s politics for 50 years. He owed much of his success to serving the needs of Irish immigrants in exchange for votes. He centralized the powers of patronage in his own hands and distributed public works jobs so as to retain the loyalty and support of his working-class electoral base. As mayor, he brought the city close to bankruptcy by spending enormous sums on parks and hospitals to satisfy his various constituencies. Unable to win a seat in the Massa¬ chusetts delegation to the 1932 Democratic convention, Curley contrived by means he never explained to be elected a delegate from Puerto Rico. As governor of Massachusetts (1935-37), he spent New Deal funds lav¬ ishly on roads, bridges, and other public works programs. He won a seat in the House of Representatives in 1942 and was reelected two years later. His last mayoral term included five months in prison following a convic¬ tion for mail fraud; Pres. Harry Truman secured his release and later granted him a full pardon. His colourful career inspired Edwin O’Connor’s novel The Last Hurrah (1956). His autobiography, I’d Do It Again, was published in 1957.
© 2006 Encyclopaedia Britannica, Inc.
496 I curling ► Curtis Institute of Music
curling Game in which two teams of four players each slide a round stone by means of a gooseneck handle on the top over a 138-ft (42-m) stretch of ice toward a target circle. The object is to deliver the stone clos¬ est to the centre (called the house). Each player delivers two stones, which average 40 lbs (18.1 kg) apiece, often applying a curl to the stone’s tra¬ jectory. The player’s teammates use a broom to sweep the ice ahead of the oncoming stone in order to facilitate a longer slide or to adjust the arc of the curl. Blocking and knocking out an opponent’s stones are impor¬ tant strategies of the sport. Curling originated in Scotland in the early 16th century. World championships have been held since 1959 and are usually dominated by Canadians and Scandinavians. In 1998 curling became a medal sport in the Winter Olympic Games.
The British women's curling team competing in the final match at the 2002 Winter Olympics in Salt Lake City, Utah.
ROBERTO SCHMIDT-AFP/GETTY IMAGES
currant Any shrub of at least 100 species in the genus Ribes, in the gooseberry family, native to temper¬ ate climates of the Northern Hemi¬ sphere and western South America.
The Rocky Mountains are especially rich in species. The flavorful, juicy red or black berries are used chiefly in jams and jellies. Black currants are used in lozenges and for flavor¬ ing, and are occasionally fermented.
Currants are extremely high in vita¬ min C and also supply calcium, phosphorus, and iron. The name cur¬ rant is also given to a seedless raisin frequently used in cooking.
currency In industrialized nations, the portion of the national money sup¬ ply (consisting of banknotes and government-issued paper money and coins) that does not require endorsement to serve as a medium of exchange. Since the abandonment of the gold standard, governments have not been obli¬ gated to repay the holders of currency in any form of precious metal. Con¬ sequently, the volume of currency has been determined by the actions of the government or central bank and not by the supply of precious metals. In less-developed societies, or in times of economic scarcity, items such as livestock or tobacco (cigarettes) may serve as currency. See also coinage.
current, density See density current current, electric See electric current
Currie, Sir Arthur William (b. Dec. 5, 1875, Napperton, Ont., Can.—d. Nov. 30, 1933, Montreal, Que.) Canadian military leader. He was a businessman in Victoria, B.C., before enlisting in the militia. Given command of a battalion in 1914, he won distinction in several battles of World War I; within three years he was promoted to lieutenant general and given command of the four divisions of the Canadian Corps. After the war he served as the first general in the Canadian army. In 1920 he became principal and vice chancellor of McGill University.
Currier and Ives partnership q/ Nathaniel Currier and James Merritt Ives (respectively b. March 27, 1813, Roxbury, Mass., U.S.—d. Nov. 20, 1888, New York, N.Y.; b. March 5, 1824, New York City—d. Jan. 3, 1895, Rye, N.Y.) U.S. lithographers. Currier served apprentice¬ ships in Boston and Philadelphia before he set up in business in New York City in 1835. He hired Ives as a bookkeeper and made him his partner in 1857. Currier and Ives greatly increased the public demand for graphic images by publishing fine-quality, black-and-white and hand-coloured lithographs (see lithography) depicting disasters, political satire, views of city life, outdoor country scenes, and sentimental domestic scenes. They established outlets across the country and in London. Between 1840 and 1890 they published more than 7,000 titles. The firm continued under their sons until 1907.
curry (from Tamil kari, “sauce”) Dish or sauce in Indian cuisine. It is seasoned with a mixture of spices often including turmeric, cumin, corian¬ der, ginger, as well as garlic and chiles. Some of the curry spices are known for their antiseptic and preservative properties. Curries have been a part of South Asian cookery since antiquity. The primarily vegetarian curries of southern India are the most pungent. Those of northern India, where lamb and poultry are eaten, generally avoid hot or pungent ingre¬ dients.
curtain Panel of decorative fabric hung to regulate the admission of light at a window and to prevent drafts. Curtains made of a heavy material, arranged to fall in ornamental folds to the floor, are called draperies. Mosaics from the 2nd-6th century show curtains suspended from rods spanning arches. From the Middle Ages to the 19th century, curtains ranged in style from simple to ornamented; beds were often curtained on all sides. In the 20th century, synthetic fabrics and mechanical devices for opening and closing curtains simplified their installation and use.
curtain wall Nonbearing wall of glass, metal, or masonry attached to a building’s exterior structural frame. After World War II, low energy costs gave impetus to the concept of the tall building as a glass prism, an idea originally put forth by Le Corbusier and Ludwig Mies van der Rohe in their visionary projects of the 1920s. The UN’s Secretariat Building (1949), with its green-tinted glass walls, helped set a worldwide standard for sky¬ scrapers.
Curtis, Charles Gordon (b. Jan. 25, 1860, Kansas Territory, U.S.—d. Feb. 8, 1936, Washington, D.C.) U.S. inventor. An associate of Thomas Alva Edison, Curtis patented the Curtis steam turbine in 1896. Its principles are still used in large ocean liners and other naval vessels; General Elec¬ tric Co. has used it worldwide in its power installations. Curtis is also credited with inventing the first U.S. gas turbine, held many patents for diesel-engine improvements, and helped develop propulsion mechanisms for naval torpedoes.