| ratio | 1. <mathematics> The relation which one quantity or magnitude has to another of the same kind. It is expressed by the quotient of the division of the first by the second; thus, the ratio of 3 to 6 is expressed by 3/6/ or 1/2; of a to b by a/b; or (less commonly) the second is made the dividend; as, a:b = b/a. Some writers consider ratio as the quotient itself, making ratio equivalent to a number. The term ratio is also sometimes applied to the difference of two quantities as well as to their quotient, in which case the former is called arithmetical ratio, the latter, geometrical ratio. The name ratio is sometimes given to the rule of three in arithmetic. See Rule. 2. Hence, fixed relation of number, quantity, or degree; rate; proportion; as, the ratio of representation in Congress. Compound ratio, Duplicate ratio, Inverse ratio, etc. See Compound, Duplicate, etc. Ratio of a geometrical progression, the constant quantity by which each term is multiplied to produce the succeeding one. Origin: L, fr. Reri, ratus, to reckon, believe, think, judge. See Reason. Source: Websters Dictionary (01 Mar 1998) |
|---|---|
| ratio imaging fluorescence microscopy | <procedure> A method of measurement of intracellular pH or intracellular calcium levels, using a fluorescent probe molecule (see fura-2), in which the two different excitation wavelengths are used and the emitted light levels compared. If emission at one wavelength is sensitive to the intracellular ion level and emission at the other wavelength is not, then standardisation for intracellular probe concentration, efficiency of light collection, inactivation of probe and thickness of cytoplasm can all be performed automatically. (17 Dec 1997) |
| ratio of decayed and filled surfaces | An index of decayed and filled permanent surfaces per person, per full complement of 122 tooth surfaces. (05 Mar 2000) |
| ratio of decayed and filled teeth | An index of decayed and filled permanent teeth per person, per full complement of 28 teeth. (05 Mar 2000) |
| ratio scale | A scale that involves physical units and demonstrates their relations. (05 Mar 2000) |
| ration | 1. A fixed daily allowance of provisions assigned to a soldier in the army, or a sailor in the navy, for his subsistence. Officers have several rations, the number varying according to their rank or the number of their attendants. 2. Hence, a certain portion or fixed amount dealt out; an allowance; an allotment. Origin: F, fr. L. Ratio a reckoning, calculation, relation, reference, LL. Ratio ration. See Ratio. Source: Websters Dictionary (01 Mar 1998) |
| rational | 1. Relating to reason; not physical; mental. "Moral philosophy was his chiefest end; for the rational, the natural, and mathematics . . . Were but simple pastimes in comparison of the other." (Sir T. North) 2. Having reason, or the faculty of reasoning; endowed with reason or understanding; reasoning. "It is our glory and happiness to have a rational nature." (Law) 3. Agreeable to reason; not absurd, preposterous, extravagant, foolish, fanciful, or the like; wise; judicious; as, rational conduct; a rational man. 4. <chemistry> Expressing the type, structure, relations, and reactions of a compound; graphic; said of formulae. See Formula. Rational horizon. <astronomy> See Horizon, 2 . <mathematics> Rational quantity, one elicited by the statements of the patient himself and not as the result of a physical examination. Synonym: Sane, sound, intelligent, reasonable, sensible, wise, discreet, judicious. Rational, reasonable. Rational has reference to reason as a faculty of the mind, and is opposed to traditional; as, a rational being, a rational state of mind, rational views, etc. In these cases the speculative reason is more particularly, referred to. Reasonable has reference to the exercise of this faculty for practical purposes, and means, governed or directed by reason; as, reasonable prospect of success. "What higher in her society thou find'st Attractive, human, rational, love still." (Milton) "A law may be reasonable in itself, although a man does not allow it, or does not know the reason of the lawgivers." (Swift) Origin: L. Rationalis: cf. F. Rationnel. See Ratio, Reason, and cf. Rationale. Source: Websters Dictionary (01 Mar 1998) |
| rational drug design | <pharmacology> Modeling the molecular structure of the target of a drug, for example, an antigen, and then designing a drug that will attack it. (17 Dec 1997) |
| rational formula | In chemistry, a formula that indicates the constitution as well as the composition of a substance. (05 Mar 2000) |
| rational surface | <physics> Magnetic flux surface where the ratio of toroidal to poloidal field strengths is a rational number, this means that a particle travelling along this surface makes an integer number of turns in each direction and then its orbit closes in on itself. The result is that the particle does not sample the entire flux surface in its motion, which is important for various technical reasons (which mostly result in reduced confinement). See: magnetic island. (09 Oct 1997) |
| rational therapy | Therapeutic procedures introduced by Albert Ellis and based on the premise that lack of information or illogical thought patterns are basic causes of a patient's difficulties; it is assumed that the patient can be assisted in overcoming his or her problems by a direct, prescriptive, advice-giving approach by the therapist. (05 Mar 2000) |
| rationalism | 1. The doctrine or system of those who deduce their religious opinions from reason or the understanding, as distinct from, or opposed to, revelation. 2. <philosophy> The system that makes rational power the ultimate test of truth; opposed to sensualism, or sensationalism, and empiricism. Origin: Cf. F. Rationalisme. Source: Websters Dictionary (01 Mar 1998) |
| rationalization | A defense mechanism operating unconsciously, in which the individual attempts to justify or make consciously tolerable, by plausible means, feelings, behaviour, and motives that would otherwise be intolerable. (12 Dec 1998) |
| rationalize | 1. To make rational; also, to convert to rationalism. 2. To interpret in the manner of a rationalist. 3. To form a rational conception of. 4. <mathematics> To render rational; to free from radical signs or quantities. Source: Websters Dictionary (01 Mar 1998) |
| absolute terminal innervation ratio | The number of motor endplates divided by the number of terminal axons related to them. (05 Mar 2000) |
|---|---|
| accommodative convergence-accommodation ratio | The amount of convergence (measured in prism diopters of convergence) divided by the amount of accommodation (measured in diopters) required to direct both eyes upon an object. (05 Mar 2000) |
| A/G ratio | <abbreviation> Albumin-globulin ratio. (05 Mar 2000) |
| albumin-globulin ratio | The ratio of albumin to globulin in the serum or in the urine in kidney disease; the normal ratio in the serum is approximately 1.55. (05 Mar 2000) |
| ALT:AST ratio | The ratio of serum alanine aminotransferase to serum aspartate aminotransferase; elevated serum levels of both enzymes characterise hepatic disease; when both levels are abnormally elevated and the ALT:AST ratio is greater than 1.0, severe hepatic necrosis or alcoholic hepatic disease is likely; when the ratio is less than 1.0, an acute non-alcoholic hepatic condition is favoured. (05 Mar 2000) |
| amylase-creatinine clearance ratio | A test for the diagnosis of acute pancreatitis; it is determined by measuring amylase and creatinine in serum and urine in apparently healthy individuals the renal clearance of amylase is less than 5% that of creatinine; in acute pancreatitis the ratio is said to be greater than 0.05 or 5%. (05 Mar 2000) |
| aspect ratio | <radiobiology> In toroidal geometry, the ratio of the major diameter (total width of the torus) to the minor diameter (width of a slice taken through one side of the ring). In inertial-confinement fusion, aspect ratio refers to the ratio of a fuel pellet's radius to its wall thickness. (09 Oct 1997) |
| at/gc ratio | <molecular biology> The ratio of adenine-thymine base pairs to guanine-cytosine base pairs on a DNA molecule. (09 Oct 1997) |
| basic reproductive rate, ratio | <epidemiology> See Reproductive Ratio. (05 Dec 1998) |
| body-weight ratio | Body weight (in grams) divided by stature (in centimeters). (05 Mar 2000) |
| branching ratio | <radiobiology> In a fusion reaction involving two nuclei, there are typically a variety of possible sets of products which can form. The branching ratio for a particular set of products is the probability that that set of products will be produced. (09 Oct 1997) |
| cardiothoracic ratio | The ratio of the horizontal diameter of the heart to the inner diameter of the rib cage at its widest point as determined on a chest roentgenogram. (05 Mar 2000) |
| magnetogyric ratio | In nuclear magnetic resonance, the ratio of the magnetic dipole moment of the nucleus to the nuclear spin angular momentum; the gyromagnetic ratio is a unique value for each type of nucleus. Synonym: magnetogyric ratio. (05 Mar 2000) |
| variance ratio | The distribution of the ratio of two independent estimates of the same variance from a gaussian distribution based on samples of sizes (n + 1) and (m + 1) respectively. Estimates are usually based on one such sample analyzed in such a way as to make them independent e.g., analysis of variance; and F may be used to test a null hypothesis that the observed differences among sample means is no greater than could readily be accounted for by chance. (05 Mar 2000) |
| G+C ratio | <molecular biology> In DNA (or RNA) from any organism, the percent of the total nucleic acid that consists of guanine plus cytosine bases. (20 Mar 1998) |