| virgin generation | <biology> Development of an ovum without fusion of its nucleus with a male pronucleus to form a zygote. (18 Nov 1997) |
|---|---|
| sexual generation | Reproduction by conjugation, or the union of male and female cells, as opposed to asexual generation. (05 Mar 2000) |
| skipped generation | A phenomenon of pedigrees in which a gene is transmitted from one affected person to another through a phenotypically unaffected person, as by recessivity (especially for X-linked traits), epistasis, variable expressivity, or absence of an environmental challenge such as a toxin. Except at a crass phenotypic level (e.g., clinical or commercial) this term becomes progressively less useful as the mechanisms are elucidated. (05 Mar 2000) |
| spontaneous generation | The obsolete hypothesis that living organisms can originate from nonliving matter. (09 Oct 1997) |
| nonsexual generation | Reproduction by fission, gemmation, or in any other way without union of the male and female cell, or conjugation. See: parthenogenesis. Synonym: heterogenesis, nonsexual generation. (05 Mar 2000) |
| f-1 generation | <genetics> Filial-One generation. The first generation of offspring which results after mating or genetically crossing two types of parents with different genotypes or phenotypes. (The parents are known as the P generation.) (09 Oct 1997) |
| f-2 generation | <genetics> Filial-Two generation. The generation of offspring which results from mating or genetically crossing members of the F-1 generation to each other. Members of this generation are two generations removed from the original parent generation, or the P generation. (09 Oct 1997) |
| filial generation | The offspring of a genetically specified mating: first filial generation (symbol F1), the offspring of parents of contrasting genotypes; second filial generation (F2), the offspring of two F1 individuals; third filial generation (F3), fourth filial generation (F4), etc., the offspring in succeeding generation's of continued inbreeding of F1 descendents. (05 Mar 2000) |
| magnetic | 1. A magnet. "As the magnetic hardest iron draws." (Milton) 2. Any metal, as iron, nickel, cobalt, etc, which may receive, by any means, the properties of the loadstone, and which then, when suspended, fixes itself in the direction of a magnetic meridian. Source: Websters Dictionary (01 Mar 1998) |
| magnetic attraction | The force that draws iron or steel toward a magnet. (05 Mar 2000) |
| magnetic axis | <physics> This typically refers to the location of the innermost flux surface in a toroidal device, the one which encloses no volume and has therefore degenerated from a flux surface into a single field line. Roughly, the circle through the middle of the dough of the donut. Additionally, in systems with magnetic islands (see entry below), each island has a local magnetic axis, distinct from the overall magnetic axis of the torus. (09 Oct 1997) |
| magnetic confinement | <physics> Use of magnetic fields to confine a plasma. (Confinement involves restricting the volume of the plasma and/or restricting particle or energy transport from the centre of the plasma to the edge.) (09 Oct 1997) |
| magnetic confinement fusion | <physics> Method of fusion which uses magnetic fields / magnetic bottles to confine a hot plasma until fusion occurs. (09 Oct 1997) |
| magnetic field | The sphere of influence of a magnet. (05 Mar 2000) |
| magnetic field gradient | In magnetic resonance imaging, a magnetic field that varies with location, superimposed on the uniform field of the magnet, to alter the resonant frequency of nuclei and allow recovery of their spatial position. Synonym: field gradient. (05 Mar 2000) |