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Hamilton, Sir William Rowan

(Encyclopedia)Hamilton, Sir William Rowan, 1805–65, Irish mathematician and astronomer, b. Dublin. A child prodigy, he had mastered 13 languages by the age of 13 and was still an undergraduate when he became prof...

Goh Chok Tong

(Encyclopedia)Goh Chok Tong gō chôk tông [key], 1941–, prime minister of Singapore (1990–2004). After holding government and business positions, he was elected to Singapore's parliament in 1976 and served in...

gravel

(Encyclopedia)gravel, particles of rock, i.e., stones and pebbles, usually round in form and intermediate in size between sand grains and boulders. Gravel is composed of various kinds of rock, the most common const...

fumaric acid

(Encyclopedia)fumaric acid fyo͞omărˈĭk [key] or trans-butenedioic acid, HO2CCH=CHCO2H, unsaturated dicarboxylic acid that melts at 287℃. Maleic acid, or cis-butenedioic acid, is a geometric isomer of fumaric ...

episome

(Encyclopedia)episome ĕpˈĭsōm [key], unit of genetic material composed of a series of genes that sometimes has an independent existence in a host cell and at other times is integrated into a chromosome of the c...

Devils Tower National Monument

(Encyclopedia)Devils Tower National Monument, 1,347 acres (546 hectares), overlooking the Belle Fourche River, NE Wyo.; it was the first designated U.S. national monument (1906). Devils Tower, 865 ft (264 m) high a...

Duflo, Esther

(Encyclopedia)Duflo, Esther, 1972–, French-American economist, b. Paris, Ph.D. Massachusetts Institute of Technology, 1999. She has been a professor of economics at the Massachusetts Institute of Technology since...

control systems

(Encyclopedia)control systems, combinations of components (electrical, mechanical, thermal, or hydraulic) that act together to maintain actual system performance close to a desired set of performance specifications...

Colden, Cadwallader

(Encyclopedia)Colden, Cadwallader kōlˈdən [key], 1688–1776, colonial scholar and political leader of New York, b. Ireland, of Scottish parents. After studying medicine in London, Colden arrived (1710) in Phila...