| NCV | Nerve Conduction Velocity |
|---|---|
| AFV | amniotic fluid volume; aortic flow velocity |
| AV | Adriamycin and vincristine; air velocity; allergic vasculitis; anteroventral; anteversion; anticipat... |
| av | air velocity; average; avulsion |
| AVI | air velocity index; Association of Veterinary Inspectors |
| aperture, angular | <microscopy> The angle between the most divergent rays that can pass through a lens to form the image of an object. The angle subtended between the axis of a lens and the largest accepted angle of the image-forming rays. With microscope objectives the trigonometric sine of this angle is used to define numerical aperture but as measured from the axial object point. (05 Aug 1998) |
|---|---|
| artery of angular gyrus | The last branch of the terminal part of the middle cerebral artery distributed to parts of the temporal parietal and occipital lobes. Synonym: arteria gyri angularis, angular artery. (05 Mar 2000) |
| supra-angular | <anatomy> See Surangular. Source: Websters Dictionary (01 Mar 1998) |
| Alfven velocity | <physics, radiobiology> Phase velocity of the Alfven wave, equal to the speed of light divided by the square root of (1 plus the ratio of the plasma frequency to the cyclotron frequency for a given species). Va = c / SQRT(1 + plasma frequency / cyclotron frequency) (13 Nov 1997) |
| blood flow velocity | A value equal to the total volume flow divided by the cross-sectional area of the vascular bed. (12 Dec 1998) |
| velocity | The time rate of motion, the distance traveled divided by the time required to travel that distance. (09 Oct 1997) |
| velocity coefficient | The rate of transformation of a unit mass of substance in a chemical reaction. (05 Mar 2000) |
| velocity constants | Proportionality constants equal to the initial rate of a reaction divided by the concentration of the reactant(s); e.g., in the reaction A → B + C, the rate of the reaction equals -d[A]/dt = k1[A]. The rate constant k1 is a unimolecular rate constant since there is only one molecular species reacting and has units of reciprocal time (e.g., sec-1). For the reverse reaction, B + C → A, the rate equals -d[B]/dt = d[A]/dt = k2[B][C]. The rate constant k2 is a bimolecular rate constant and has units of reciprocal concentration-time (e.g., m-1 sec-1). Synonym: velocity constants. (05 Mar 2000) |
| velocity space | <radiobiology> Mathematical space where each point corresponds not to a certain location in reality, but to a certain velocity. Distribution functions typically involve mixes of both position and velocity spaces. (See distribution function.) Contrast with position space where each point corresponds to a given location. (09 Oct 1997) |
| velocity space instability | <radiobiology> A class of instabilities driven by particle distributions (in velocity space) which are not in thermal equilibrium. (09 Oct 1997) |
| maximum velocity | The maximum rate of an enzyme-catalyzed reaction that can be achieved by progressively increasing the substrate concentration at a given enzyme concentration; in cases of substrate inhibition, Vmax is an extrapolated value in the absence of such inhibition; Cf.: Michaelis-Menten equation. The maximum initial rate of shortening of a myocardial fibre that can be obtained under zero load; used to evaluate the contractility of the fibre. (05 Mar 2000) |
| group velocity | <radiobiology> This is derived from the dispersion relation as Vgroup = dw/dk, the group velocity is the rate at which modulations or information within a wave travel through a given medium. (09 Oct 1997) |
| critical velocity | <biology> The maximum speed a device or organism can sustain over a specified distance or length of time, or the maximum velocity against which device or organism can sustain a position over a specified length of time. <marine biology> Velocity through which a fish will not swim, creating a velocity barrier. (09 Oct 1997) |
| sedimentation velocity | The rate of movement of a substance, typically a macromolecule, in centrifugation; these centrifugation studies provide data on the structure of the macromolecule. (05 Mar 2000) |
| steady-state velocity | The velocity of an enzyme-catalyzed reaction in which, over the time course of the study, the concentration of any enzyme species is constant (i.e., for an enzyme-substrate binary complex, ES, d[ES]/dt&apprxeq;00; for this to hold true, the total enzyme concentration must be much less than the initial substrate concentration. Synonym: steady-state rate. (05 Mar 2000) |