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gonadotropic hormone

(Encyclopedia)gonadotropic hormone gōˌnădətrŏpˈĭk [key] or gonadotropin, any one of three glycoprotein (see protein) hormones released by either the anterior pituitary gland or the placenta (the organ in whi...

Ali, Muhammad

(Encyclopedia)Ali, Muhammad məhămˈəd älēˈ [key], 1942–2016, American boxer, b. Louisville, Ky. Born Cassius Marcellus Clay, he was a 1960 Olympic gold medalist. Shortly after upsetting Sonny Liston in 1964...

alkaloid

(Encyclopedia)alkaloid, any of a class of organic compounds composed of carbon, hydrogen, nitrogen, and usually oxygen that are often derived from plants. Although the name means alkalilike, some alkaloids do not e...

feathers

(Encyclopedia)CE5 Structure of a bird feather feathers, outgrowths of the skin, constituting the plumage of birds. Feathers grow only along certain definite tracts (pterylae), which vary in different groups of ...

vasectomy

(Encyclopedia)vasectomy, male sterilization by surgical excision of the vas deferens, the thin duct that carries sperm cells from the testicles to the prostate and the penis. Vasectomy is a popular method of birth ...

psychosomatic medicine

(Encyclopedia)psychosomatic medicine sīˌkōsōmătˈĭk [key], study and treatment of those emotional disturbances that are manifested as physical disorders. The term psychosomatic emphasizes essential unity of t...

International Geophysical Year

(Encyclopedia)International Geophysical Year (IGY), 18-month period from July, 1957, through Dec., 1958, during a period of maximum sunspot activity, designated for cooperative study of the solar-terrestrial enviro...

symmetry

(Encyclopedia)symmetry, generally speaking, a balance or correspondence between various parts of an object; the term symmetry is used both in the arts and in the sciences. In art and design, it is often used in a s...

burlesque

(Encyclopedia)burlesque bûrlĕskˈ [key] [Ital.,=mockery], form of entertainment differing from comedy or ...

aging

(Encyclopedia)aging, in biology, cumulative changes in an organism, organ, tissue, or cell leading to a decrease in functional capacity. In humans, aging is associated with degenerative changes in the skin, bones, ...