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varicose vein

(Encyclopedia)varicose vein, superficial vessel that is abnormally lengthened, twisted, or dilated, seen most often on the legs and thighs. Varicose veins develop spontaneously, and are usually attributed to a here...

catabolism

(Encyclopedia)catabolism kətăbˈəlĭzˌəm [key], subdivision of metabolism involving all degradative chemical reactions in the living cell. Large polymeric molecules such as polysaccharides, nucleic acids, and ...

sun worship

(Encyclopedia)sun worship. Deification and adoration of the sun occurred primarily in agrarian societies. When man became a farmer, and thus dependent upon daily and seasonal changes of weather, he often turned to ...

Calderón, Alberto

(Encyclopedia)Calderón, Alberto käldārōnˈ [key], 1920–98, Argentine mathematician, b. Mendoza, Argentina, grad. Univ. of Buenos Aires (B.S. 1947), Univ. of Chicago (Ph.D. 1950). He is known for his contribut...

aerogel

(Encyclopedia)aerogel, any of a group of extremely light and porous solid materials; the lightest is less than four times as dense as dry air. Aerogels are produced from certain gels (see colloid) by heating the ge...

water moccasin

(Encyclopedia)water moccasin or cottonmouth, highly venomous snake, Ancistrodon piscivorus, of the swamps and bayous of the S United States. Like the closely related copperhead, it is a pit viper and has a heat-sen...

Waters, Ethel

(Encyclopedia)Waters, Ethel, 1896?–1977, African-American singer and actress, b. Chester, Pa. As a singer, she is noted for her sultry, sophisticated, and dramatic version of the blues, evinced in her interpretat...

weather satellite

(Encyclopedia)weather satellite, artificial satellite used to gather data on a global basis for improvement of weather forecasting. Information includes cloud cover, storm location, temperature, and heat balance in...

glacial periods

(Encyclopedia)glacial periods, times during which large portions of the earth's surface were covered with thick glacial ice sheets. In the Pleistocene epoch, in the Carboniferous and Permian periods of the Paleozoi...

first aid

(Encyclopedia)first aid, immediate and temporary treatment of a victim of sudden illness or injury while awaiting the arrival of medical aid. Proper early measures may be instrumental in saving life and ensuring a ...