| reciprocal transfusion | An attempt to confer immunity by transfusing blood taken from a donor into a receiver suffering from the same affection, the balance being maintained by transfusing an equal amount from the receiver to the donor. (05 Mar 2000) |
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| reciprocal translocation | Translocation without demonstrable loss of genetic material. (05 Mar 2000) |
| reciprocal treanslocation | Mutual exchange of chromosome segments between two nonhomologous chromosomes (chromosomes that do not belong to the same pair). (12 Dec 1998) |
| reversed reciprocal rhythm | A cardiac arrhythmia in which a normal sinus impulse, before reaching the ventricles, is reflected backward to the atria; thus in the electrocardiogram a ventricular complex is sandwiched between a normal sinus P wave and a retrograde P wave; if the dysrhythmia continues, subsequent cycles are similar to those of reciprocating rhythm. (05 Mar 2000) |
| double-reciprocal plot | <statistics> A graph made to analyse how fast an enzyme can convert its substrate into its product, depending on how much substrate is present (its concentration) and to determine its maximum speed (after which the enzyme does not get any faster no matter how high the concentration of substrate gets), called Vmax. It is a plot of 1/v versus 1/[S], where v=rate of product formation and [S]=the concentration of the substrate. Synonym: Lineweaver-Burk plot, Woolf-Lineweaver-Burk plot. (05 Mar 2000) |
| Abbe's law of limiting resolution | <physics> For a periodic structure of units separated by distance d and obliquely illuminated by the unrefracted ray and one of the two diffracted rays (extremely oblique illumination). Abbe applied the law of diffraction: d = 0.5 lambda /NA, where: lambda = wavelength of the monochromic light or shortest of mixed wavelengths NA = the limiting numerical aperture (NA) of objective or condenser. (05 Aug 1998) |
| all or none law | Consistently total response to any effective stimulus. Synonym: all or none law. (05 Mar 2000) |
| American Law Institute formulation | Used in certain jurisdictions to determine criminal responsibility in legal proceedings. See: criminal insanity. (05 Mar 2000) |
| American Law Institute rule | A test of criminal responsibility (1962): "a person is not responsible for criminal conduct if at the time of such conduct as a result of mental disease or defect he lacks substantial capacity either to appreciate the wrongfulness of his conduct or to conform his conduct to the requirements of law." (05 Mar 2000) |
| Ampere's law | <physics> General equation in electromagnetism relating the magnetic field and the currents generating it. The various forms of the equation can be found in an introductory electromagnetism text. (09 Oct 1997) |
| Angstrom's law | A substance absorbs light of the same wavelength as it emits when luminous. (05 Mar 2000) |
| Arndt's law | An obsolete law stating that weak stimuli excite physiologic activity, moderately strong ones favour it, strong ones retard it, and very strong ones arrest it. (05 Mar 2000) |
| Arrhenius law | The theory of electrolytic dissociation (1887) that became the basis of our modern understanding of electrolytes: in an electrically conductive solution (e.g., acid, base, or salt), free ions are present before electrolysis, and the proportion of molecules dissociated into ions can be calculated from measurements of electrical conductivity as well as of osmotic pressure. Synonym: Arrhenius law. (05 Mar 2000) |
| Avogadro's law | Equal volumes of gases contain equal numbers of molecules, the conditions of pressure and temperature being the same. Synonym: Ampere's postulate, Avogadro's hypothesis, Avogadro's postulate. (05 Mar 2000) |
| Baer's law | The general organ characteristics found in all members of a group appear earlier in embryogenesis than the special organ characteristics that distinguish specific members of the group; this law is the predecessor of the recapitulation theory. (05 Mar 2000) |