| quantum | <unit> The fundamental unit of electromagnetic energy. (09 Oct 1997) |
|---|---|
| quantum efficiency | The number of photons required for the formation of one oxygen molecule in photosynthesis. Varies from 8-14 depending on the system used to measure it. (18 Nov 1997) |
| quantum evolution | An extremely rapid evolutionarychange in a single genetic lineage, thought to result from a sudden and radical change in the species'environment. (09 Oct 1997) |
| quantum limit | The shortest wavelength found in an X-ray spectrum. (05 Mar 2000) |
| quantum mottle | Mottle caused by the statistical fluctuation of the number of photons absorbed by the intensifying screens to form the light image on the film; faster screens produce more quantum mottle. (05 Mar 2000) |
| quantum rectum | See: Q.R. Origin: L. However much is correct (05 Mar 2000) |
| quantum requirement | The number of quanta of light absorbed required for the transformation of one molecule; the inverse of the quantum yield. (05 Mar 2000) |
| quantum satis | See: q.s. Origin: L. However much is enough Quantum sink, in radiological imaging, the stage at which statistical information reaches its lowest level because of a low photon flux. (05 Mar 2000) |
| quantum speciation | The rapid evolution of a newspecies from a small population that ispartially or totally isolated from the parent population, the rapidspeciation occurs due to geneticdrift and founder effect and usuallyinvolves a few mutations that have a big impact on the organisms' observable physical traits. (09 Oct 1997) |
| quantum sufficiat | See: q.s. Origin: L. However much is enough (05 Mar 2000) |
| quantum theory | The theory that the radiation and absorption of energy take place in definite quantities called quanta (e) which vary in size and are defined by the equation e=hv in which h is planck's constant and v is the frequency of the radiation. (12 Dec 1998) |
| quantum vis | See: q.v.. Origin: L. However much you wish (05 Mar 2000) |
| quantum yield | The number of photons required for the formation of one oxygen molecule in photosynthesis. Varies from 8-14 depending on the system used to measure it. (18 Nov 1997) |
| alternating light test | Test to detect a relative afferent defect in one eye by watching pupillary movements. With the patient fixing in the distance, the light is held on each eye for about a second, and quickly moved to the other eye. Assuming no defect of the innervation to the iris sphincter in one eye (which would produce an anisocoria in light), the eye with the weaker light response has a relative afferent pupillary defect. This asymmetry of pupillomotor input can be estimated by holding neutral density filters in front of the better eye until the pupillary responses of the two eyes are balanced. Synonym: swinging light test. (05 Mar 2000) |
| Begg light wire differential force technique | An orthodontic appliance utilizing small gauge labial wires with expansion and contraction loops formed into it and attached to bands fitted to individual teeth; sometimes called Begg light wire differential force technique. (05 Mar 2000) |