| DRAM | dynamic random access memory |
|---|---|
| DRES | dynamic random element stimuli |
| E(X) | expected value of the random variable X |
| MRF | Markov random field; medical record file; melanocyte-[stimulating hormone]-releasing factor; mesence... |
| RAM | random-access memory; rapid alternating movements; rectus abdominis muscle; rectus abdominis myocuta... |
| mixed discrete-continuous random variable | <statistics> A random variable that may assume some values with probabilities and others with probability densities. For example, in a 35-year-old man with familial polyposis of the colon, the distribution of time until malignant disease occurs consists of a probability that he already has cancer (which would be assigned the waiting time 0), a probability density of developing it in the future and a probability that he will die of some other cause before he develops cancer. (05 Mar 2000) |
|---|---|
| continuous random variable | Continuous variable that may randomly assume any value in its domain but any particular value has no probability of occurring, only a probability density. (05 Mar 2000) |
| sample, random | A group selected randomly, solely by chance. (12 Dec 1998) |
| pure random drift | That which has random components only with an average value of zero and no systematic effects. Brownian movement in a still container shows pure random drift but in the Mississippi shows a steady downstream tendency. (05 Mar 2000) |
| discrete random variable | A random variable that may assume a countable number of values, each with a probability strictly greater than zero. (05 Mar 2000) |
| ordered on-random off mechanism | A scheme for substrate binding and product release for multisubstrate enzymes; for a two-substrate two-product enzyme with this mechanism, the individuals have to bind to the enzyme in a distinct order; however, once the products are formed they may dissociate from the enzyme in either order. It has been suggested that pyruvate kinase has such a mechanism. The random on-ordered off mechanism is simply the reverse of this mechanism. (05 Mar 2000) |
| atomic number | <chemistry> Symbol Z. The number of protons in the nucleus of an atom and also its characteristic atomic number. The atomic numbers of the known elements form a complete series from 1 (hydrogen) to 103 (lawrencium). (16 Dec 1997) |
| Avogadro's number | <physics> The number of molecules in a mole (gram molecular weight) of a substance, equals 6.02 x 1023 molecules. (09 Oct 1997) |
| Brinell hardness number | A number related to the size of the permanent impression made by a ball indenter of specified size (usually 10 mm in diameter) pressed into the surface of the material under a specified load: where P = applied load in kg, D = diameter of the ball in mm, and d = diameter of the impression in mm. (05 Mar 2000) |
| burst number | The number of viral particles that emerge from a cell after a viralinfection has burst it open. (09 Oct 1997) |
| Mach number | A number representing the ratio between the speed of an object moving through a fluid medium, such as air, and the speed of sound in the same medium. (05 Mar 2000) |
| magnetic mach number | <physics> A dimensionless number equal to the ratio of the velocity of a fluid to the velocity of Alfven waves in that fluid. (13 Nov 1997) |
| mass number | The mass of the atom of a particular isotope relative to hydrogen-1 (or to 1/12 the mass of carbon-12), generally very close to the whole number represented by the sum of the protons and neutrons in the atomic nucleus of the isotope (indicated in the name or symbol of the isotope; e.g., oxygen-16, 16O); not to be confused with the atomic weight of an element, which may include a number of isotopes in natural proportion. (05 Mar 2000) |
| Reichert-Meissl number | An index of the volatile acid content of a fat; the number of milliliters of 0.1 n KOH required to neutralise the soluble volatile fatty acids in 5 g of fat that has been saponified, acidified to liberate the fatty acids, and then steam-distilled. Synonym: volatile fatty acid number. (05 Mar 2000) |
| volatile fatty acid number | An index of the volatile acid content of a fat; the number of milliliters of 0.1 n KOH required to neutralise the soluble volatile fatty acids in 5 g of fat that has been saponified, acidified to liberate the fatty acids, and then steam-distilled. Synonym: volatile fatty acid number. (05 Mar 2000) |