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image

(Encyclopedia)image, in optics, likeness or counterpart of an object produced when rays of light coming from that object are reflected from a mirror or are refracted by a lens. An image of an object is also formed ...

shock

(Encyclopedia)shock, any condition in which the circulatory system is unable to provide adequate circulation to the body tissues, also called circulatory failure or circulatory collapse. Shock results in the slowin...

probiotic

(Encyclopedia)probiotic, live microorganism administered to a host with the intention of providing a health benefit, or a food, supplement, or treatment containing such microorganisms. Many of the microbes found in...

photochemistry

(Encyclopedia)photochemistry, study of chemical processes that are accompanied by or catalyzed by the emission or absorption of visible light or ultraviolet radiation. A molecule in its ground (unexcited) state can...

medicine man

(Encyclopedia)medicine man, among Native Americans and other traditional peoples as far back as Paleolithic times, a person believed to possess supernatural healing powers. Like the shaman the medicine man was a sp...

rheostat

(Encyclopedia)rheostat rēˈəstătˌ [key], device whose resistance to electric current depends on the position of some mechanical element or control in the device. Typically a rheostat consists of a resistance el...

ringworm

(Encyclopedia)ringworm or tinea tĭnˈēə [key], superficial eruption of the skin caused by a fungus, chiefly Microsporum, Trichophyton, or Epidermophyton. Any area of the skin may be affected, including the scalp...

fistula

(Encyclopedia)fistula fĭsˈcho͝olə [key], abnormal, usually ulcerous channellike formation between two internal organs or between an internal organ and the skin. It may follow a surgical procedure with improper ...

Popper-Lynkeus, Josef

(Encyclopedia)Popper-Lynkeus, Josef yōˈzĕf pôpˈər-lünˈkāo͝os [key], 1838–1921, Austrian philosopher, social reformer, and inventor. His unpopular views kept him from any academic position, so he worked ...

antisense

(Encyclopedia)antisense, DNA or RNA manipulated in a laboratory so that its components (nucleotides) form a complementary copy of normal, or “sense,” messenger RNA (mRNA; see nucleic acid). Antisense techniques...