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Theodora

(Encyclopedia)Theodora thēədôrˈə [key], d. 548, Byzantine empress. Information about her early career comes from the often-questionable source, the Secret History of Procopius. It appears that she was the daug...

threat

(Encyclopedia)threat, in law, declaration of intent to injure another by doing an unlawful act, with a view to restraining his freedom of action. A threat is distinguishable from an assault, for an assault requires...

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...

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...

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...

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...

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...

Parks, Gordon

(Encyclopedia)Parks, Gordon (Gordon Roger Alexander Buchanan Parks), 1912–2006, African-American photographer, filmmaker, writer, and composer, b. Fort Scott, Kans. Parks purchased his first camera in 1938 and be...

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 ...