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Pittsfield
Pittsfield city (1990 pop. 48,622), seat of Berkshire co., W Mass., between mountain ranges, on branches of the Housatonic River; inc. as a town 1761, as a city 1889. The city is the metropolis of the Berkshire resort area. Once a farming community, it developed industrially in the 19th cent. as a ...
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antidiuretic hormone
antidiuretic hormone , polypeptide hormone secreted by the posterior pituitary gland . Its principal action is to regulate the amount of water excreted by the kidneys. Antidiuretic hormone (ADH), known also as vasopressin, causes the kidneys to resorb water directly from the renal tubules, thus con...
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arrowhead
arrowhead any plant of the genus Sagittaria, widely distributed marsh or aquatic herbs of the primitive family Alismataceae (water-plantain family). The name derives from the arrowhead-shaped leaves of many species. Native North Americans prepared a potatolike food by roasting or broiling the tub...
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advertising
advertising in general, any openly sponsored offering of goods, services, or ideas through any medium of public communication. At its inception advertising was merely an announcement; for example, entrepreneurs in ancient Egypt used criers to announce ship and cargo arrivals. The invention of print...
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chemical equation
chemical equation group of symbols representing a chemical reaction .
Basic Notation Used in Equations
The chemical equation 2H 2 +O 2 →2H 2 O represents the reaction of hydrogen and oxygen to form water. The arrow points in the direction of the reaction—from the reactants (su...
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tempering
tempering process involving slow and moderate heating to increase the hardness and toughness of metals that have undergone previous heat treatment. Metals are usually hardened (see hardening ) by being heated to high temperatures and quenched rapidly. This treatment causes brittleness, which is re...
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cold fusion
cold fusion or low-temperature fusion, nuclear fusion of deuterium, an isotope of hydrogen , at or relatively near room temperature. Fusion, the reaction involved in the release of the destructive energy of a hydrogen bomb , requires extremely high temperatures, and investigations of fusion a...
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Nashua
Nashua , city (1990 pop. 79,662), seat of Hillsborough co., S N.H., on the Merrimack and Nashua rivers near the Mass. line; settled c.1655, inc. as a city 1853. Because of the availability of water power, Nashua developed (early 19th cent.) as a textile mill town; the closing of these mills after Wo...
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polychlorinated biphenyl
polychlorinated biphenyl or PCB, any of a group of organic compounds originally widely used in industrial processes but later found to be dangerous environmental pollutants. Polychlorinated biphenyl is a fat-soluble, water-insoluble hydrocarbon containing chlorine. It is extremely stable, withs...
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sodium nitrate
sodium nitrate chemical compound, NaNO 3 , a colorless, odorless crystalline compound that closely resembles potassium nitrate (saltpeter or niter) in appearance and chemical properties. It is soluble in water, alcohol, and liquid ammonia. Sodium nitrate is also called soda niter or Chile saltpeter...
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