| horizontal survey | <epidemiology> A study of a community, perhaps stratified by age, sex, ethnicity etc., but at one point in time or over a short time interval. Although a snapshot, horizontal surveys of prevalence and intensity within different age classes of a community can nevertheless provide valuable information on the rate at which hosts acquire infection through time, provided that the host and parasite populations have remained approximately stable for a period of time (i.e. Stable endemicity). Same as cross-sectional study , converse of longitudinal study. (05 Dec 1998) |
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| skeletal survey | A radiographic examination of all or selected parts of the skeleton, as for occult fractures, metastases, etc. (05 Mar 2000) |
| survey | 1. To inspect, or take a view of; to view with attention, as from a high place; to overlook; as, to stand on a hill, and survey the surrounding country. "Round he surveys and well might, where he stood, So high above." (Milton) 2. To view with a scrutinizing eye; to examine. "With such altered looks, . . . All pale and speechless, he surveyed me round." (Dryden) 3. To examine with reference to condition, situation, value, etc.; to examine and ascertain the state of; as, to survey a building in order to determine its value and exposure to loss by fire. 4. To determine the form, extent, position, etc, of, as a tract of land, a coast, harbor, or the like, by means of linear and angular measurments, and the application of the principles of geometry and trigonometry; as, to survey land or a coast. 5. To examine and ascertain, as the boundaries and royalties of a manor, the tenure of the tenants, and the rent and value of the same. Origin: OF. Surveoir, surveer; sur, sor, over, E. Sur + veoir, veeir, to see, F. Voir, L. Videre. See Sur-, and Vision, and cf. Supervise. Source: Websters Dictionary (01 Mar 1998) |
| survey line | A line scribed on an abutment tooth of a dental cast by means of a dental surveyor indicating the height of contour of the tooth according to a specific path of insertion, a line which serves as a guide in the proper location of various parts of a clasp assembly for a removable partial denture. Synonym: clasp guideline, Cummer's guideline. (05 Mar 2000) |
| field survey | The planned collection of data among noninstitutionalised persons in the general population. (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) |
| radio frequency current drive | <radiobiology> Plasma waves in the radio-frequency range can be used to push plasma particles in such a way that current forms in the plasma, this is a method of non-inductive current drive which would allow for steady-state fusion reactors to operate. (09 Oct 1997) |
| radio frequency heating | <radiobiology> Process for heating the plasma by transferring energy to ions or electrons using waves generated by an external oscillator at an appropriate frequency. (This is similar to how a microwave oven heats food.) There are various types: See: ECRH, ICRH, and Lower Hybrid. (09 Oct 1997) |
| 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) |
| 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) |