| high frequency transduction | Specialised transduction in which the donor bacterium contains not only the transducing, defective probacteriophage but also nondefective prophage that serves as "helper" virus, enabling most of the defective prophage particles to develop sufficiently to function as transducing agents. (05 Mar 2000) |
|---|---|
| high-frequency ventilation | Ventilatory support system using frequencies from 60-900 cycles/min or more. Three types of systems have been distinguished on the basis of rates, volumes, and the system used. They are high frequency positive-pressure ventilation (hfppv), high-frequency jet ventilation (hfjv), and high-frequency oscillation (hfo). (12 Dec 1998) |
| nearest neighbor frequency | The frequency by which certain types of entities or structures are immediately adjacent to a given structure. (05 Mar 2000) |
| dominant frequency | The frequency occurring most often in an electroencephalogram. (05 Mar 2000) |
| flicker fusion frequency technique | A technique of perimetry using the criterion of critical fusion frequency. Synonym: flicker fusion frequency technique. (05 Mar 2000) |
| Larmor frequency | In magnetic resonance, the precessional frequency, n0, of magnetic nuclei in a plane perpendicular to the direction of the external magnetic field; v0 = gB0/2π, where B0 is the magnetic field strength and g is the magnetogyric ratio. (05 Mar 2000) |
| frequency | 1. <physics> The number of occurrences of a periodic or recurrent process per unit time, for example the number of vibrations of a particle per second or the number of repetitions of a complete wave form (cycles) per second. 2. <statistics> The number of members of a population or statistical sample falling in a particular class. 3. Relative frequency, the average number of occurrences of a particular event in a large number of repeated trials. (07 Apr 1998) |
| 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) |
| 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) |