Columbia Encyclopedia

Search results

500 results found

Mendel, Gregor Johann

(Encyclopedia)Mendel, Gregor Johann grāˈgôr yōˈhän mĕnˈdəl [key], 1822–84, Austrian monk noted for his experimental work on heredity. He entered the Augustinian monastery in Brno in 1843, taught at a loc...

skin cancer

(Encyclopedia)skin cancer, malignant tumor of the skin. The most common types of skin cancer are basal cell carcinoma, squamous cell carcinoma, and melanoma. Rarer forms include mycosis fungoides (a type of lymphom...

pear

(Encyclopedia)pear, name for a fruit tree of the genus Pyrus of the family Rosaceae (rose family) and for its fruit, a pome. The common pear (P. communis) is one of the earliest cultivated of fruit trees, both in i...

nitric oxide

(Encyclopedia)nitric oxide or nitrogen monoxide, a colorless gas formed by the combustion of nitrogen and oxygen as given by the reaction: energy + N2 + O2 → 2NO; m.p. −163.6℃; b.p. −151.8℃. Nitric oxide ...

micromechanics

(Encyclopedia)micromechanics, the combination of minuscule electrical and mechanical components in a single device less than 1 mm across, such as a valve or a motor. Although micromechanical production processes an...

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...

schistosomiasis

(Encyclopedia)schistosomiasis bĭlˌhärzīˈəsĭs [key], or snail fever, parasitic disease caused by blood flukes, trematode worms of the genus Schistosoma. Three species are human parasites: S. mansoni, S. japon...

screamer

(Encyclopedia)screamer, common name for gregarious, aquatic birds comprising three species in the family Anhimidae. Although they are related to the ducks and geese, they do not resemble them in outward appearance....

chorionic villus sampling

(Encyclopedia)chorionic villus sampling (CVS) or chorionic villus biopsy (CVB) kōrˌē-ŏnˈĭk, kôrˌ– [key], diagnostic procedure in which a sample of chorionic villi from the developing placenta is removed f...

collagen

(Encyclopedia)collagen kŏlˈəjən [key], any of a group of proteins found in skin, ligaments, tendons, bone and cartilage, and other connective tissue. Cells called fibroblasts form the various fibers in connecti...