| 释义 |
linkage|ˈlɪŋkɪdʒ|
[f. link n.2 or v.1 + -age.]
a. The condition or manner of being linked; a system of links. Also, a link; an association or correlation; the process of linking or connecting (see also quots.). Also attrib.
Applied e.g. (Chem.) to the union of atoms or radicals in a molecule; (Geom.) to a system of straight lines, etc. pivoted together so as to rotate about one another (by Sylvester used with restricted application; see quot. 1874 for link-work, link n.2 7).
1874Sylvester in Proc. Roy. Instit. VII. 182 note, A compass or a pair of scissors is the simplest form of linkage; a set of lazy-tongs is another. 1877Kempe (title) How to draw a straight line; a lecture on linkages. 1887Jrnl. Franklin Inst. Jan. 74 Brühl showed that in case of ‘double-linkage’ each such carbon-atom has a refraction equivalent to about 6·1. 1890Spectator 11 Sept. 462/1 Chemists are persuaded that the ethylenic form of linkage is not the equivalent of two paraffinic linkages. 1893Cayley in Coll. Math. Papers (1897) XIII. 292 The results given by the MacMahon linkage. 1897Standard 1 Feb. 5/2 The linkage of life to life in Nature. 1899Allbutt's Syst. Med. VI. 512 Such places of linkage of neurons being called ‘synapses’. 1904Brit. & Colonial Printer 10 Mar. 14/2 A linkage system transmits the movement to the slide bars. 1928A. S. Eddington Nature Physical World xiv. 306 If the two structures were identifiable then the atom would involve a complete causal connection of the two types of phenomena. But apparently no such causal linkage exists. 1940Chambers's Techn. Dict. 503/2 Linkage (Elec. Eng.), a measure of the product of the magnetic flux passing through a closed electric circuit and the number of turns in the circuit, the unit being one line passing through a circuit having one turn. 1957Educational & Psychol. Measurement XVII. 207 (title) Elementary linkage analysis for isolating orthogonal and oblique types and typal relevancies. 1959B. Higgins Econ. Devel. iv. xvi. 405 Any particular investment project may have both ‘forward linkage’ (may encourage investment in subsequent stages of production) and ‘backward linkage’ (may encourage investment in earlier stages of production). The task is to find the projects with the greatest total linkage. Ibid. xvii. 413 Favoring deliberate unbalancing of the economy to maximize the ‘linkage’ effects of investment. 1959Science CXXX. 954/1 The term record linkage has been used to indicate the bringing together of two or more separately recorded pieces of information. 1962K. W. Gatland Astronautics in Sixties xi. 344 Radar..may be relied upon to achieve linkage of the spacecraft. 1962Which? Car Suppl. Oct. 143/1 Modified carburettor and linkage to give smoother operation. 1963F. W. Frey in L. W. Pye Communications & Political Devel. xvii. 301 The ratio of the number of existing power linkages..to the number of theoretically possible linkages. 1969J. N. Rosenau (title) Linkage politics. 1970Nature 24 Oct. 387/2 There follows a discussion of the linkages between population growth and food supplies.
b. Genetics. (An) association between characters in inheritance, such that if one parent has a pair of characters, there is a probability greater than 50% that any offspring inheriting one of the characters will also inherit the other, which effect is due to the two characters being controlled by alleles located on the same chromosome; formerly called (gametic) coupling (coupling vbl. n. 6 e); also, the amount or degree of this association (varying between 50% and 100%). Also attrib.
1912Biol. Bull. XXIII. 175 There are no wingless black flies in the F2 generation, which the Mendelian expectation calls for. Their absence can only be explained by strong linkage of the yellow factor and the factor for wings. Ibid. 178 There are actually 1,858 long grey flies to 916 long black, or a ratio of 2 to 1. This is the linkage ratio when two strongly or completely linked factors are concerned. 1915T. H. Morgan et al. Mechanism Mendelian Heredity iii. 58 In the case of yellow and white just given the linkage between the two factors is very strong. 1928Hereditas X. 126 The linkages P1–V and B–V have been reported by Wellensiek. 1940Chambers's Techn. Dict. 503/2 Linkage group, a group of hereditary characteristics which remain associated with one another through a number of generations. Ibid. 504/1 Linkage map, a diagram showing the position of the genes in a chromosome or group of chromosomes. 1958Oxf. Univ. Gaz. 23 Apr. 892 Genetic investigations on mice with special reference to evolutionary processes and linkage. 1959Listener 3 Dec. 967/1 We shall need to know how many chromosomes there are, and what may be the importance of the phenomenon called ‘linkage’ in keeping the genes on one chromosome together. 1970Ambrose & Easty Cell Biol. x. 339 The genes [of Drosophila] fell into four linkage groups, which corresponded with the haploid number of four chromosomes. Ibid. 340 However far apart two genes are,..they will never show less than 50 per cent linkage due to multiple cross-overs.
Sense a in Dict. becomes 1 a; sense b in Dict. becomes 2. Add: [1.] b. spec. in Pol., the linking together of different political issues as a strategy for negotiations between countries, esp. by stipulating that progress on one front is necessary for progress on any other.
1969Washington Post 9 Feb. 2/1 President Nixon now seeks to develop a linkage between the most discussed subject of future U.S.-Soviet negotiations, the control and cutback of nuclear missilery, and basic East-West political tensions... His associates, now are trying to clarify the ‘linkage’ concept. 1973New Yorker 19 May 112/3 Diplomatic circles recorded that Moscow was unhappy about linkages. 1976U.S. News & World Rep. 29 Mar. 17/3 In the Angola operation, Kremlin leaders ignored ‘linkage’ and also violated the agreement to steer clear of such tension-building actions. 1979Time 8 Jan. 34/1 The real stumbling block is ‘linkage’—the relationship between an Egyptian–Israeli treaty and a wider Middle East settlement. 1986N.Y. Times 13 Nov. a30/1 You can't talk about arms control when Soviet behavior in other areas is unacceptable, Mr. Reagan said. ‘In other words, I believe in linkage.’ 1991Independent 15 Jan. 19/1 To support linkage would be to dilute the original demand of the UN and encourage President Saddam to believe that he could stay in Kuwait without a war. Linkage became a code-word for political softness. |