| frequency analysis | <ecology, statistics> A method of evaluating vegetation in an area by establishing a transect and counting the occurrences of plant species at various sampling points along the transect. (07 Apr 1998) |
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| frequency 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) |
| frequency distribution | A statistical description of raw data in terms of the number or frequency of items characterised by each of a series or range of values of a continuous variable. (05 Mar 2000) |
| frequency domain | The expression of a function by its amplitude and phase at each component frequency, usually as determined by Fourier analysis. (05 Mar 2000) |
| frequency encoding | In magnetic resonance imaging, a method of varying the magnetic field strength with location to encode the location of each voxel uniquely in one direction. (05 Mar 2000) |
| frequency of micturition | Micturition at short intervals; it may result from increased urine formation, decreased bladder capacity, or lower urinary tract irritation. (05 Mar 2000) |
| frequency of occurrence | The number of times a given event occurs at specified sample points during a defined period. (07 Apr 1998) |
| frequency spectrum | The range of frequencies in a signal, used to describe the resolving power of an imaging system in radiology. (05 Mar 2000) |
| frequency, urinary | Urinating too often, at too frequent intervals, not due to an unusually large volume of urine, but rather to a decrease in the capacity of the bladder to hold urine. (12 Dec 1998) |
| fundamental frequency | The principal component of a sound wave, which has the greatest wavelength, tone produced by the vibration of the vocal folds before the air reaches any cavities. (05 Mar 2000) |
| low frequency transduction | Specialised transduction in which only a small portion of the prophage particles, because of their defectiveness, are able to develop sufficiently to serve as effective transducing agents. (05 Mar 2000) |
| aaa disease | Endemic anaemia of ancient Egypt, ascribed in the Papyrus Ebers to intestinal infestation with ancylostoma; now called ancylostomiasis. (05 Mar 2000) |
| ABO haemolytic disease of the newborn | Erythroblastosis foetalis due to maternal-foetal incompatibility with respect to an antigen of the ABO blood group; the foetus possesses A or B antigen which is lacking in the mother, and the mother produces immune antibody which causes haemolysis of foetal erythrocytes. (05 Mar 2000) |
| accumulation disease | A disease characterised by abnormal accumulation of a metabolic product in certain cells and tissues; examples include the mucopolysaccharidoses, lipoidoses. (05 Mar 2000) |
| Acosta's disease | A condition that results from prolonged exposure to high altitude. Symptoms include a continuous dry cough, shortness of breath, poor exercise tolerance, dizziness, headache, sleep difficulty, anorexia, confusion, fatigue and a rapid pulse. Treatment includes the immediate movement to a lower altitude. Prophylaxis has been accomplished successfully with the use of acetazolamide (Diamox). (27 Sep 1997) |