| AF | abnormal frequency; acid-fast; adult female; afebrile; aflatoxin; albumin-free; albumose-free; aldeh... |
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| FTC | Federal Trade Commission; follicular thyroid carcinoma; frequency threshold curve; frequency tuning ... |
| HFO | high-frequency oscillator; high-frequency oscillatory [ventilation] |
| Hfr | heart frequency; high frequency |
| HFT | high-frequency transduction; high-frequency transfer |
| normal distribution | Continuous frequency distribution of infinite range. Its properties are as follows: 1) continuous, symmetrical distribution with both tails extending to infinity; 2) arithmetic mean, mode, and median identical; and 3) shape completely determined by the mean and standard deviation. (12 Dec 1998) |
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| dermatomal distribution | The area of skin innervated by a single posterior spinal nerve (sensory nerve). (27 Sep 1997) |
| distribution | 1. The specific location or arrangement of continuing or successive objects or events in space or time. 2. The extent of a ramifying structure such as an artery or nerve and its branches. 3. The geographical range of an organism or disease. 4. Probability. Origin: L. Distributio (11 Jan 1998) |
| distribution coefficient | The ratio of concentrations of a substance in two immiscible phases at equilibrium; the basis of many chromatographic separation procedures. Synonym: partition coefficient. (05 Mar 2000) |
| distribution curve | A systematic grouping of data into classes or categories according to the frequency of occurrence of each successive value or ranges of such values, resulting in a graph of a frequency distribution. Synonym: frequency curve. (05 Mar 2000) |
| distribution function | <radiobiology> Function characterising the density of particles located at a given point in phase space (a combination of velocity and/or position coordinates) at a given time. The velocity-space distribution function gives the number of particles with a particular velocity, the position-space distribution function is synonymous with the particle density in position-space. Different combinations of position and spatial coordinates are useful in different problems. (09 Oct 1997) |
| distribution leukocytosis | An abnormally large proportion of one or more types of leukocytes. (05 Mar 2000) |
| distribution volume | The volume throughout which an added tracer substance appears to have been evenly distributed, calculated by dividing the amount of tracer added by its concentration after equilibration. (05 Mar 2000) |
| t distribution | The distribution of the quotient of independent random variables, the numerator of which is a standardised normal variate and the denominator the positive square root of the quotient of a chi-square distributed variate and its number of degrees of freedom. (05 Mar 2000) |
| tissue distribution | Accumulation of a drug or chemical substance in various organs (including those not relevant to its pharmacologic or therapeutic action). This distribution depends on the blood flow or perfusion rate of the organ, the ability of the drug to penetrate organ membranes, tissue specificity, protein binding. The distribution is usually expressed as tissue to plasma ratios. (12 Dec 1998) |
| epidemiological distribution | See: histogram. (05 Mar 2000) |
| exponential distribution | The time until failure of a process at constant hazard. (05 Mar 2000) |
| f distribution | The distribution of the ratio of two independent quantities each of which is distributed like a variance in normally distributed samples. So named in honor of the English statistician and geneticist R.A. Fisher. (05 Mar 2000) |
| lognormal distribution | If a variable y is such that x = log y, it is said to have a lognormal distribution; this is a skew distribution. (05 Mar 2000) |
| bounce frequency | <physics> The average frequency of oscillation of a particle trapped in a magnetic mirror as it bounces back and forth between its turning points in regions of high magnetic field. (See also trapped particle, turning points, banana orbit). (09 Oct 1997) |