| radio frequency or radiofrequency | <physics> Term used to describe electromagnetic radiation with frequencies less than infrared, but greater than audio frequencies, i.e., greater than about 15,000 Hz. Wavelengths are therefore less than about 20,000 km and greater than about 0.01 mm. (These numbers are not precise.) (09 Oct 1997) |
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| gene frequency | The relative occurence (expressed as a percentage) of a gene in a given population. (09 Oct 1997) |
| recombination frequency | The frequency at which crossingover occurs between two chromosomal loci--the probability that twoloci will become unlinked during meiosis. (09 Oct 1997) |
| resonant frequency | The frequency at which individual magnetic nuclei absorb or emit radiofrequency energy in magnetic resonance studies. Synonym: resonance. (05 Mar 2000) |
| respiratory frequency | The number of breaths per minute. (05 Mar 2000) |
| collision frequency | <chemistry> The rate at which chemical species collide, used in theories of chemical kinetics. Also, the frequency with which gaseous molecules collide. (09 Oct 1997) |
| plasma frequency | <radiobiology> The natural collective oscillation frequency of a charge species (electrons, ions, etc.) in a plasma, in the absence of (or at least parallel to) a magnetic field. Also known as Langmuir or Langmuir-Tonks frequency. See: electrostatic waves, plasma oscillations. (09 Oct 1997) |
| mutational frequency | The proportions of mutations in a population. (05 Mar 2000) |
| critical flicker fusion frequency | The minimal number of flashes of light per second at which an intermittent light stimulus no longer stimulates a continuous visual sensation. (05 Mar 2000) |
| cyclotron frequency | <radiobiology> Number of times per second that a particle orbits a magnetic field line. The frequency is completely determined by the strength of the field and the particle's charge-to-mass ratio. (Often, and incorrectly, called the Larmor frequency. The cyclotron or gyrofrequency is twice the Larmor frequency of precession.) (09 Oct 1997) |
| 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) |