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osteoporosis

(Encyclopedia)osteoporosis ŏsˌtēōˌpərōˈsĭs [key], disorder in which the normal replenishment of old bone tissue is severely disrupted, resulting in weakened bones and increased risk of fracture; osteopenia...

boron

(Encyclopedia)boron bōrˈŏn [key] [New Gr. from borax], chemical element; symbol B; at. no. 5; interval in which at. wt. ranges 10.806–10.821; m.p. about 2,300℃; sublimation point about 2,550℃; sp. gr. 2.3 ...

blast furnace

(Encyclopedia)CE5 Blast furnace for production of iron blast furnace, structure used chiefly in smelting. The principle involved in this means of extracting metals is that of the reduction of the ores by the ac...

protozoan

(Encyclopedia)protozoan prōˌtəzōˈən [key], informal term for the unicellular heterotrophs of the kingdom Protista. Protozoans comprise a large, diverse assortment of microscopic or near-microscopic organisms ...

adaptation

(Encyclopedia)adaptation, in biology, has several meanings. It can mean the adjustment of living matter to environmental conditions and to other living things either in an organism's lifetime (physiological adaptat...

uranium

(Encyclopedia)uranium yo͞orāˈnēəm [key], radioactive metallic chemical element; symbol U; at. no. 92; mass number of most stable isotope 238; m.p. 1,132℃; b.p. 3,818℃; sp. gr. 19.1 at 25℃; valence +3, +4...

aquaculture

(Encyclopedia)aquaculture, the raising and harvesting of fresh- and saltwater plants and animals. The most economically important form of aquaculture is fish farming, an industry that accounts for an ever increasin...

arteriosclerosis

(Encyclopedia)arteriosclerosis ärtĭrˌēōsklərōˈsis [key], general term for a condition characterized by thickening, hardening, and loss of elasticity of the walls of the blood vessels. These changes are freq...

Giuliani, Rudolph William

(Encyclopedia)Giuliani, Rudolph William jo͞oˌlē-äˈnē [key], 1944–, American government official, b. Brooklyn, N.Y. He attended Manhattan College and studied law at New York Univ. In the Justice Dept. as ass...

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...