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mezzotint

(Encyclopedia)mezzotint mĕtˈsətĭnt, mĕdˈzə–, mĕzˈə– [key] [Ital.,=halftint], method of copper or steel engraving in tone. A Dutch officer, Ludwig von Siegen, is given credit for the invention of mezzo...

neoteny

(Encyclopedia)neoteny nēŏtˈənē [key], in biology, sexual maturity reached in the larval stage of some animals. Certain environmental conditions can inhibit the completion of metamorphosis; low temperature or l...

castration

(Encyclopedia)castration, removal of the sex glands of an animal, i.e., testes in the male, or ovaries and often the uterus in the female. Castration of the female animal is commonly referred to as spaying. Castrat...

sponge

(Encyclopedia)sponge, common name for members of the aquatic animal phylum Porifera, and for the dried, processed skeletons of certain species used to hold water. Over 4,500 living species are known; they are found...

cryptogam

(Encyclopedia)cryptogam, in botany, term used to denote a plant that produces spores, as in algae, fungi, mosses, and ferns, but not seeds. The term cryptogam, from the Greek kryptos, meaning “hidden,” and gamo...

hermaphrodite

(Encyclopedia)hermaphrodite hərmăfˈrədītˌ [key], animal or plant that normally possesses both male and female reproductive systems, producing both eggs and sperm. Many plants, including most flowering plants ...

Barye, Antoine Louis

(Encyclopedia)Barye, Antoine Louis äNtwänˈ lwē bärēˈ [key], 1796–1875, French animal sculptor. Son of a Parisian goldsmith, he followed his father's trade as a youth. In 1832 he exhibited at the Salon his ...

protease inhibitor

(Encyclopedia)protease inhibitor prōˈtē-āsˌ [key], any of a class of drugs that interfere with replication of the AIDS virus (HIV), by blocking an enzyme (protease) necessary in the late stages of its reproduc...

distortion

(Encyclopedia)distortion, in electronics, undesired change in an electric signal waveform as it passes from the input to the output of some system or device. In an audio system, distortion results in poor reproduct...

Guillemin, Roger Charles Louis

(Encyclopedia)Guillemin, Roger Charles Louis gēyəmăNˈ [key], 1924–, French-American physiologist, b. Dijon, France. Educated in France, he fought for the resistance during World War II. He taught primarily at...