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focus
focus in optics, the point at which rays converge after reflection by a concave mirror or refraction by a convex lens , also known as a real focus. The point from which rays appear to diverge after reflection by a convex mirror or refraction by a concave lens is known as a virtual focus. See im...
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parabola
parabola , plane curve consisting of all points equidistant from a given fixed point (focus) and a given fixed line (directrix) (see illustration) . It is the conic section cut by a plane parallel to one of the elements of the cone. The axis of a parabola is the line through the focus perpendic...
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Wilt Chamberlain
Wilt Chamberlain (Wilton Norman Chamberlain), 1936-99, American basketball player, b. Philadelphia. At the Univ. of Kansas he was a two-time All-American center. During 14 seasons in the National Basketball Association, "Wilt the Stilt" (over 7 ft 1 in./216 cm) led the league in scoring seven c...
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National Academy of Sciences
National Academy of Sciences with headquarters in Washington, D.C., a private organization of leading American scientists and engineers devoted to the furtherance of science and its use for the general welfare. The Academy was founded in 1863; there are presently about 2,000 members. Members are el...
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Madison: Introduction
Madison: Introduction
The capital of Wisconsin, Madison is also the seat of Dane County and the focus of a metropolitan statistical area that includes the entire county. The city was founded as the state capital, where no other permanent settlement had previously existed, on a unique geographic sit...
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Philip Ainsworth Means
Philip Ainsworth Means 1892-1944, American historian and archaeologist, b. Boston. An assistant on a Yale expedition to Peru (1914-15), he was later (1920-21) director of the National Museum of Archaeology at Lima, Peru. He traveled widely in Latin American countries, and between 1921 and 1932 he w...
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Hamilton
Hamilton city (1990 est. pop. 3,100), capital of Bermuda , on Bermuda Island. It is a port at the head of Great Sound, a huge lagoon and deepwater harbor protected by coral reefs. The city is the focus of Bermuda's commercial and social life and is a major tourist resort.
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astigmatism
astigmatism , type of faulty vision caused by a nonuniform curvature in the refractive surfaces—usually the cornea, less frequently the lens—of the eye. As a result, light rays do not all come to a single focal point on the retina. Instead, some focus on the retina while others focus in ...
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Consett
Consett , town (1991 pop. 33,433), Durham, NE England. The major economic focus is on engineering. The town has associations with the Roman, Saxon, and Norman conquests. A German colony of swordmakers settled in Consett in the 17th cent.
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George Alfred Henty
George Alfred Henty 1832-1902, English author. Initially a war correspondent, he later wrote boys' adventure tales that were very popular. Henty's books all focused on an ideal of manly virtue. They include The Young Bugler (1880) and With Clive in India (1884).
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