Columbia Encyclopedia

Search results

500 results found

ruby

(Encyclopedia)ruby, precious stone, the transparent red variety of corundum, found chiefly in Myanmar, Thailand, and Sri Lanka and classified among the most valuable of gems. The Myanmarese stones are blood red, th...

scalp

(Encyclopedia)scalp, the integument covering the top of the head. It consists of three layers of tissue: the skin, an underlying layer of tissue and blood vessels, and the occipitofrontalis muscle stretching from t...

infarction

(Encyclopedia)infarction, blockage of blood circulation to a localized area or organ of the body resulting in tissue death. Infarctions commonly occur in the spleen, kidney, lungs, brain, and heart. The acute emerg...

trade winds

(Encyclopedia)trade winds, movement of air toward the equator, from the NE in the Northern Hemisphere and from the SE in the Southern Hemisphere. The trade winds originate on the equatorial sides of the horse latit...

temperature inversion

(Encyclopedia)temperature inversion, condition in which the temperature of the atmosphere increases with altitude in contrast to the normal decrease with altitude. When temperature inversion occurs, cold air underl...

autoimmune disease

(Encyclopedia)autoimmune disease, any of a number of abnormal conditions caused when the body produces antibodies to its own substances. In rheumatoid arthritis, a group of antibody molecules called collectively RF...

urinalysis

(Encyclopedia)urinalysis yo͝orˌənălˈĭsĭs [key], clinical examination of urine for the purpose of medical diagnosis. Urine is initially examined for such characteristics as color, odor, and specific gravity. ...

serotonin

(Encyclopedia)serotonin sĕrˌətōˈnĭn [key], organic compound that was first recognized as a powerful vasoconstrictor occurring in blood serum. It was partially purified, crystallized, and named in 1948, and it...

hydraulics

(Encyclopedia)hydraulics, branch of engineering concerned mainly with moving liquids. The term is applied commonly to the study of the mechanical properties of water, other liquids, and even gases when the effects ...

Nuttall, George Henry Falkiner

(Encyclopedia)Nuttall, George Henry Falkiner nŭtˈôl [key], 1862–1937, American-British bacteriologist, b. San Francisco, M.D. Univ. of California, 1884, Ph.D. Univ. of Göttingen, 1890. In 1899 he became assoc...