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Chad, Lake

(Encyclopedia)Chad, Lake chăd, chäd [key], N central Africa. It lies mainly in Chad and Cameroon. Some 550 sq mi (1,425 sq km) in area in 2003, the shallow lake has been greatly reduced in size since the 1960s, w...

firefly

(Encyclopedia)firefly or lightning bug, small, luminescent, carnivorous beetle of the family Lampyridae. Fireflies are well represented in temperate regions, although the majority of species are tropical and subtro...

metallurgy

(Encyclopedia)metallurgy mĕtˈəlûrˌjē [key], science and technology of metals and their alloys. Modern metallurgical research is concerned with the preparation of radioactive metals, with obtaining metals econ...

salt, chemical compound

(Encyclopedia)salt, chemical compound (other than water) formed by a chemical reaction between an acid and a base (see acids and bases). Salts are also prepared by methods other than neutralization. A metal can c...

phosphorylation

(Encyclopedia)phosphorylation, chemical process in which a phosphate group is added to an organic molecule. In living cells phosphorylation is associated with respiration, which takes place in the cell's mitochondr...

Sachs, Jeffrey David

(Encyclopedia)Sachs, Jeffrey David săks [key], 1954–, American economist, b. Detroit; grad. Harvard (B.A. 1976, M.A. 1978, Ph.D. 1980). He joined the Harvard faculty in 1980, and became a full professor three ye...

trypanosome

(Encyclopedia)trypanosome trĭpˈənəsōmˌ [key], microscopic, one-celled protozoan of the genus Trypanosoma, typically living as an active parasite in the bloodstream of a vertebrate; hundreds of species are kno...

acid rain

(Encyclopedia)acid rain or acid deposition, form of precipitation (rain, snow, sleet, or hail) containing high levels of sulfuric or nitric acids (pH below 5.5–5.6). Produced when sulfur dioxide and various nitro...

americium

(Encyclopedia)americium ămərĭˈshēəm [key], artificially produced radioactive chemical element; symbol Am; at. no. 95; mass no. of most stable isotope 243; m.p. about 1,175℃; b.p. about 2,600℃; sp. gr. 13....

Draghi, Mario

(Encyclopedia)Draghi, Mario mäˈēō drägˈē [key], 1947–, Italian economist and government and international ...