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Weiss, Rainer

(Encyclopedia)Weiss, Rainer, 1932–, American physicist, b. Berlin, Germany, Ph.D. Massachusetts Institute of Technology, 1962. Weiss has been on the faculty of the Massachusetts Institute of Technology since 1964...

second

(Encyclopedia)second, abbr. sec or s, fundamental unit of time in all systems of measurement. In practical terms, the second is 1/60 of a minute, 1/3,600 of an hour, or 1/86,400 of a day. Since the length of the da...

physical fitness

(Encyclopedia)physical fitness, combined good health and physical development. The object of any program of physical fitness is to maximize an individual's health, strength, endurance, and skill relative to age, se...

psoriasis

(Encyclopedia)psoriasis sôrīˈəsĭs [key], occasionally acute but usually chronic and recurrent inflammation of the skin. The exact cause is unknown, but the disease appears to be an inherited, possibly autoimmu...

radioactive waste

(Encyclopedia)radioactive waste, material containing the unusable radioactive byproducts of the scientific, military, and industrial applications of nuclear energy. Since its radioactivity presents a serious health...

polycythemia

(Encyclopedia)polycythemia pŏlˌēsīthēˈmēə [key], condition characterized by an increase in the production of red blood cells, or erythrocytes, in the blood. Primary polycythemia, also called erythremia, or ...

David, Gerard

(Encyclopedia)David or Davit, Gerard both: gāˈrärt däˈvēt [key], c.1460–1523, Flemish painter, b. Oudewater, Holland. By 1484 he had established himself in Bruges, where he remained until his death. Depende...

Paulding, James Kirke

(Encyclopedia)Paulding, James Kirke pôlˈdĭng [key], 1778–1860, American author and public official, secretary of the navy (1838–41) under Van Buren, b. near Millbrook, N.Y. He collaborated with Washington Ir...

Stuart, John McDouall

(Encyclopedia)Stuart, John McDouall, 1815–66, Scottish explorer in Australia. He emigrated (1838) to S Australia; there, as a draftsman, he joined Charles Sturt's expedition (1844–45) to central Australia. Betw...

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...