| negative | Not affirming the presence of the organism or condition in question (a negative diagnosis). (18 Nov 1997) |
|---|---|
| negative accommodation | The decrease of accommodation that occurs when shifting from near vision to distance vision. (05 Mar 2000) |
| negative afterimage | An afterimage in which the lightness relationship is reversed; if chromatic, it appears in complementary colour. (05 Mar 2000) |
| negative anergy | A reduction of the normal or usual immunologic responses because of unrelated intervening disease. Synonym: non-specific anergy. (05 Mar 2000) |
| negative base excess | A measure of metabolic acidosis, usually predicted from the Siggaard-Andersen nomogram; the amount of strong alkali that would have to be added per unit volume of whole blood to titrate it to pH 7.4 while at 37캜 and at a carbon dioxide pressure of 40 mm Hg. (05 Mar 2000) |
| negative binomial distribution | <epidemiology> A distribution which is parameterised by a mean m and an aggregation parameter k which is large when aggregation is small; in fact as k becomes large, the negative binomial distribution approximates the Poisson distribution. (05 Dec 1998) |
| negative control | Regulation of an enzyme activity by an inhibitor of that enzyme or regulation of a protein by repression of transcription. (05 Mar 2000) |
| negative convergence | The slight divergence of the visual axes when convergence is at rest, as when observing the far point or during sleep. (05 Mar 2000) |
| negative cooperativity | Cooperativity in which successive ligand molecules appear to bind with decreasing affinity. (05 Mar 2000) |
| negative crystal | <microscopy> A uniaxial crystal is optically negative if epsilon is less than omega A biaxial crystal is said to be optically negative if gamma minus beta is less than beta is less than beta minus alpha. Otherwise the crystal is positive. (05 Aug 1998) |
| negative electrode | <chemistry, physics> The electrode in an electrochemical cell toward which cations are drawn and where reduction occurs. The negatively charged electrode in a vacuum tube. (16 Mar 1998) |
| negative electrotaxis | Electrotaxis by which an organism is attracted toward an anode or repelled from a cathode. (05 Mar 2000) |
| negative end-expiratory pressure | A subatmospheric pressure at the airway at the end of expiration. (05 Mar 2000) |
| negative eyepiece | <microscopy> An eyepiece in which the real image of the object is formed between the lens elements of the eyepiece. (05 Aug 1998) |
| negative, false | A result that appears negative but fails to reveal a situation. An example of a false negative: a particular test designed to detect cancer of the toenail is negative but the person has toenail cancer. (12 Dec 1998) |