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addition
addition fundamental operation of arithmetic, denoted by +. In counting, a + b represents the number of items in the union of two collections having no common members (disjoint sets), having respectively a and b members. In geometry a + b might, for example, represent the area of the union ...
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subtraction
subtraction fundamental operation of arithmetic; the inverse of addition. If a and b are real numbers (see number ), then the number a - b is that number (called the difference) which when added to b (the subtractor) equals a (the subtrahend). In terms of addition the symbol - b is call...
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National Institute of Standards and Technology
National Institute of Standards and Technology governmental agency within the U.S. Dept. of Commerce with the mission of "working with industry to develop and apply technology, measurements, and standards" in the national interest. It was established by act of Congress on Mar. 3, 1901; until 19...
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food additives
food additives substances added to foods by manufacturers to prevent spoilage or to enhance appearance, taste, texture, or nutritive value. By quantity, the most common food additives are flavorings, which include spices, vinegar, synthetic flavors, and, in the greatest abundance, sweeteners (e.g.,...
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Sir Humphrey Gilbert
Sir Humphrey Gilbert 1537?-1583, English soldier, navigator, and explorer; half brother of Sir Walter Raleigh . Knighted (1570) for his service in the campaigns in Ireland, he later (1572) served in the Netherlands. Convinced of the existence of a Northwest Passage , he explained his theories in ...
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saturation
saturation of an organic compound, condition occurring when its molecules contain no double or triple bonds and thus cannot undergo addition reactions. For example, ethane (H 3 C-CH 3 ) is a saturated compound. A compound is called unsaturated if it can undergo addition reactions. In the unsaturate...
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Robert Burton
Robert Burton 1577-1640, English clergyman and scholar, b. Leicestershire, educated at Oxford. He served as librarian at Christ Church, Oxford, all his life; in addition he was vicar of St. Thomas, Oxford, and later was rector of Seagrave, Leicestershire. A bachelor, he led an uneventful, scholarly...
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Lake Maracaibo
Lake Maracaibo largest lake of South America, c.5,100 sq mi (13,210 sq km), NW Venezuela, extending c.110 mi (180 km) inland. A strait, 34 mi (55 km) long, connects it with the Gulf of Venezuela. Discovered in 1499 by the Spanish explorer Alonso de Ojeda, the lake lies in the extremely hot, humid l...
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ultraviolet astronomy
ultraviolet astronomy study of celestial objects by means of the ultraviolet radiation they emit, in the wavelength range from about 90 to about 350 nanometers. Ultraviolet (UV) line spectrum measurements are used to discern the chemical composition, densities, and temperatures of interstellar ga...
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Jewish liturgy
Jewish liturgy rites, observances, and procedures of Judaism. Communal prayer, with a quorum of ten men (or in some modern communities, ten people), replaced the priests of the Temple cult. There are three daily services, with additional ones for the Sabbath and festivals. The fixed components ar...
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