| differ | 1. To be or stand apart; to disagree; to be unlike; to be distinguished; with from. "One star differeth from another star in glory." (1 Cor. Xv. 41) "Minds differ, as rivers differ." (Macaulay) 2. To be of unlike or opposite opinion; to disagree in sentiment; often with from or with. 3. To have a difference, cause of variance, or quarrel; to dispute; to contend. "We 'll never differ with a crowded pit." (Rowe) Synonym: To vary, disagree, dissent, dispute, contend, oppose, wrangle. To Differ with, Differ from. Both differ from and aiffer with are used in reference to opinions; as, "I differ from you or with you in that opinion."" In all other cases, expressing simple unlikeness, differ from is used; as, these two persons or things differ entirely from each other. "Severely punished, not for differing from us in opinion, but for committing a nuisance." (Macaulay) "Davidson, whom on a former occasion we quoted, to differ from him." (M. Arnold) "Much as I differ from him concerning an essential part of the historic basis of religion." (Gladstone) "I differ with the honorable gentleman on that point." (Brougham) "If the honorable gentleman differs with me on that subject, I differ as heartily with him, and shall always rejoice to differ." (Canning) Origin: L. Differre; dif- = dis- + ferre to bear, carry: cf. F. Differer. See 1st Bear, and cf. Defer, Delay. Source: Websters Dictionary (01 Mar 1998) |
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| difference | 1. The act of differing; the state or measure of being different or unlike; distinction; dissimilarity; unlikeness; variation; as, a difference of quality in paper; a difference in degrees of heat, or of light; what is the difference between the innocent and the guilty? "Differencies of administration, but the same Lord." (1 Cor. Xii. 5) 2. Disagreement in opinion; dissension; controversy; quarrel; hence, cause of dissension; matter in controversy. "What was the difference? It was a contention in public." (Shak) "Away therefore went I with the constable, leaving the old warden and the young constable to compose their difference as they could." (T. Ellwood) 3. That by which one thing differs from another; that which distinguishes or causes to differ;; mark of distinction; characteristic quality; specific attribute. "The marks and differences of sovereignty." (Davies) 4. Choice; preference. "That now be chooseth with vile difference To be a beast, and lack intelligence." (Spenser) 5. An addition to a coat of arms to distinguish the bearings of two persons, which would otherwise be the same. See Augmentation, and Marks of cadency, under Cadency. 6. <logic> The quality or attribute which is added to those of the genus to constitute a species; a differentia. 7. <mathematics> The quantity by which one quantity differs from another, or the remainder left after subtracting the one from the other. Ascensional difference. See Ascensional. Synonym: Distinction, dissimilarity, dissimilitude, variation, diversity, variety, contrariety, disagreement, variance, contest, contention, dispute, controversy, debate, quarrel, wrangle, strife. Origin: F. Difference, L. Differentia. Source: Websters Dictionary (01 Mar 1998) |
| difference equation | <epidemiology> The mathematical formulation corresponding to a discrete time model. (05 Dec 1998) |
| differential | 1. Relating to or indicating a difference; creating a difference; discriminating; special; as, differential characteristics; differential duties; a differential rate. "For whom he produced differential favors." (Motley) 2. <mathematics> Of or pertaining to a differential, or to differentials. 3. <mechanics> Relating to differences of motion or leverage; producing effects by such differences; said of mechanism. Differential calculus. <mathematics> A portable hoisting apparatus, the same in principle as the differential windlass. A hoisting pulley to which power is applied through a differential gearing. Differential screw, a compound screw by which a motion is produced equal to the difference of the motions of the component screws. Differential thermometer, a thermometer usually with a U-shaped tube terminating in two air bulbs, and containing a coloured liquid, used for indicating the difference between the temperatures to which the two bulbs are exposed, by the change of position of the coloured fluid, in consequence of the different expansions of the air in the bulbs. A graduated scale is attached to one leg of the tube. Differential windlass, or Chinese windlass, a windlass whose barrel has two parts of different diameters. The hoisting rope winds upon one part as it unwinds from the other, and a pulley sustaining the weight to be lifted hangs in the bight of the rope. It is an ancient example of a differential motion. Origin: Cf. F. Differentiel. 1. <mathematics> An increment, usually an indefinitely small one, which is given to a variable quantity. According to the more modern writers upon the differential and integral calculus, if two or more quantities are dependent on each other, and subject to increments of value, their differentials need not be small, but are any quantities whose ratios to each other are the limits to which the ratios of the increments approximate, as these increments are reduced nearer and nearer to zero. 2. A small difference in rates which competing railroad lines, in establishing a common tariff, allow one of their number to make, in order to get a fair share of the business. The lower rate is called a differential rate. Differentials are also sometimes granted to cities. 3. <physics> One of two coils of conducting wire so related to one another or to a magnet or armature common to both, that one coil produces polar action contrary to that of the other. A form of conductor used for dividing and distributing the current to a series of electric lamps so as to maintain equal action in all. <mathematics> Partial differential, the differential of a function of two or more variables, when each of the variables receives an increment. The total differential of the function is the sum of all the partial differentials. Source: Websters Dictionary (01 Mar 1998) |
| differential adhesion | The differential adhesion hypothesis was advanced by Steinberg to explain the mechanism by which heterotypic cells in mixed aggregates sort out into isotypic territories. Quantitative differences in homo and hetero typic adhesion are supposed to be sufficient to account for the phenomenon without the need to postulate cell type specific adhesion systems: fairly generally accepted, although some tissue specific cell adhesion molecules are now known to exist. (18 Nov 1997) |
| differential blood pressure | The arterial blood pressure at corresponding points on the two sides of the body. (05 Mar 2000) |
| differential centrifugation | A technique for separating organellesor other differently-sized cellcomponents in a centrifuge, particles of the same size and weight willsettle out into common layers. (09 Oct 1997) |
| differential diagnosis | The determination of which two or more diseases with similar symptoms is the one from which a patient is suffering from based on an analysis of the clinical data. (27 Sep 1997) |
| differential display PCR | Method of image formation in the light microscope based on the method proposed by Nomarski (though strictly speaking all forms of optical microscopy rely to a greater or lesser extent on differential interference). The light beam is split by a Wollaston prism in the condenser, to form slightly divergent beams polarized at right angles. One passes through the specimen (and is retarded if the refractive index is greater) and one through the background nearby: the two are recombined in a second Wollaston prism in the objective and interfere to form an image. The image is spuriously three dimensional the nucleus, for example: appears to stand out above the cell (or be hollowed out) because it has a higher refractive index than the cytoplasm. The Nomarski system has the advantage that there is no phase halo, but the contrast is low and image formation with crowded cells is poor because the background does not differ from the specimen. (18 Nov 1997) |
| differential equation | <epidemiology> The mathematical formulation corresponding to a continuous model; an equation involving derivatives. (05 Dec 1998) |
| differential gene expression | Gene expression that responds to signals or triggers; a means of gene regulation; e.g., effects of certain hormones on protein biosynthesis. (05 Mar 2000) |
| differential growth | Different rates of growth in associated tissues or structures; used especially in embryology when the differences in growth rates result in changing the original proportions or relations. (05 Mar 2000) |
| differential interference contrast | <technique> A mode of contrast generation in microscopy that yields an image with a shadow relief. The relief reflects the gradient of optical path difference. Differential Interference Contrast, which is a form of interferenc microscopy that uses polarizing beam splitters, can be of the Smith or Nomarski type. Acronym: DIC (05 Aug 1998) |
| differential manometer | Any device that indicates the difference in pressure between two fluids, regardless of any changes in their absolute pressures. Mercurial manometer, an manometer in which the varying pressures are shown by differences of elevation in a column of mercury. (05 Mar 2000) |
| differential medium | A medium which is used to differentiate different types of microorganisms based on their different colours or colony shapes. Examples of differential media are: Macconkey's agar and SS agar. (09 Oct 1997) |