| gram-positive endospore-forming rods | <microbiology> Rod-shaped bacteria that form endospores and are gram-positive. Representative genera include bacillus and clostridium. (12 Dec 1998) |
|---|---|
| gram-positive rods | <microbiology> A large group of rod-shaped bacteria that retains the crystal violet stain when treated by gram's method. (12 Dec 1998) |
| positive | Having a value greater than zero, indicating existence or presence of a condition, organism, etc. As chromatin positive or Wassermann positive, characterised by affirmation or cooperation. Origin: L. Positivus (18 Nov 1997) |
| positive accommodation | The increased refractivity of the eye that occurs when shifting from the distance to a near object. (05 Mar 2000) |
| positive afterimage | An afterimage in which the lightness relationship is the same as the original one; if chromatic, it appears in the same colour. (05 Mar 2000) |
| positive afterpotential | A spontaneous or inducible increase in transmembrane potential of a cardiac or nerve cell following the completion of repolarization. In the heart, this usually corresponds to the electrocardiographic U wave. (05 Mar 2000) |
| positive anergy | A reduction of the normal or usual immunologic response resulting from a reaction to a specific allergen. Synonym: specific anergy. (05 Mar 2000) |
| positive control | Mechanism for gene regulation that requires that a regulatory protein must interact with some region of the gene before transcription can be activated. (18 Nov 1997) |
| positive convergence | Inward deviation of the visual axes even when convergence is at rest, as in cases of convergent squint. (05 Mar 2000) |
| positive cooperativity | Cooperativity in which successive ligand molecules appear to bind with increasing affinity. (05 Mar 2000) |
| positive electrode | <microscopy> The electrode to which a major flow of electrons takes place internally (as in a cathode-ray tube) or to which an external positive voltage supply is connected. (05 Aug 1998) |
| positive electron | A subatomic particle of mass and charge equal to the electron but of opposite (i.e., positive) charge. Synonym: positive electron. (05 Mar 2000) |
| positive electrotaxis | Electrotaxis by which an organism is attracted toward a cathode or repelled from an anode. (05 Mar 2000) |
| positive, false | A result that is erroneously positive when a situation is normal. An example of a false positive: a particular test designed to detect cancer of the toenail is positive but the person does not have toenail cancer. (12 Dec 1998) |
| positive feedback | <physiology> The return of some of the output of a system as input so as to exert some control in the process. (18 Nov 1997) |