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ester

(Encyclopedia)CE5 Esters ester, any one of a group of organic compounds with general formula RCO2R′ (where R and R′ are alkyl groups or aryl groups) that are formed by the reaction between an alcohol and an...

fertilization

(Encyclopedia)CE5 Fertilization of an egg cell fertilization, in biology, process in the reproduction of both plants and animals, involving the union of two unlike sex cells (gametes), the sperm and the ovum, f...

fertilizer

(Encyclopedia)fertilizer, organic or inorganic material containing one or more of the nutrients—mainly nitrogen, phosphorus, and potassium, and other essential elements required for plant growth. Added to the soi...

sea urchin

(Encyclopedia)sea urchin, spherical-shaped echinoderm with movable spines covering the body. The body wall is a firm, globose shell, or test, made of fused skeletal plates and marked by regularly arranged tubercles...

Shiller, Robert James

(Encyclopedia)Shiller, Robert James, 1946–, American economist, b. Detroit, grad. Univ. of Michigan (B.A., 1967), Massachusetts Institute of Technology (S.M., 1968; Ph.D., 1972). A professor at Yale since 1982, S...

phalanger

(Encyclopedia)phalanger fəlănˈjər [key], any of the numerous and varied marsupials, or pouched mammals, of the family Phalangeridae, found in Australia, New Guinea, and adjacent islands. Many are somewhat like ...

behaviorism

(Encyclopedia)behaviorism, school of psychology which seeks to explain animal and human behavior entirely in terms of observable and measurable responses to environmental stimuli. Behaviorism was introduced (1913) ...

tryptophan

(Encyclopedia)CE5 tryptophan trĭpˈtəfăn [key], organic compound, one of the 20 amino acids commonly found in animal proteins. Only the l-stereoisomer appears in mammalian protein. It is one of several essent...

Thurber, James

(Encyclopedia)Thurber, James, 1894–1961, American humorist, b. Columbus, Ohio, studied at Ohio State Univ. After working on various newspapers he served on the staff of the New Yorker from 1927 to 1933 and was la...

rhythm, biological

(Encyclopedia)rhythm, biological, or biorhythm, cyclic pattern of physiological changes or changes in activity in living organisms, most often synchronized with daily, monthly, or annual cyclical changes in the env...