| chi | 1. The 22nd letter of the Greek alphabet, χ. 2. In chemistry, denotes the 22nd in a series. 3. Symbol for the dihedral angle between the alpha-carbon and the side-chains of amino acids in peptides and proteins. (05 Mar 2000) |
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| chi sequence | <molecular biology> A specific sequence of nucleotides on a site on the genome of the bacteria Escherichia coli which strongly encourages recombination and crossing over to occur at that site. (05 Jan 1998) |
| chi site | <molecular biology> Short, active sequences of DNA which strongly encourages crossing over of chromosomes to occur at that site. These sites become chiasmata more often than other sites. (05 Jan 1998) |
| chi squared | <statistics> Common statistical test to determine whether the observed values of a variable are significantly different from those expected on the basis of a null hypothesis. (18 Nov 1997) |
| chi structure | <molecular biology> The name for the X-shaped structure which forms during the recombination process between two plasmids, or circular pieces, of DNA. The Greek letter chi resembles this structure. (05 Jan 1998) |
| chi-sequences | A specific DNA sequence in bacterial genomes that allows for extensive genetic recombination. (05 Mar 2000) |
| chi-square | A statistical technique whereby variables are categorised to determine whether a distribution of scores is due to chance or experimental factors. (05 Mar 2000) |
| chi-square distribution | A distribution in which a variable is distributed like the sum of the the squares of any given independent random variable, each of which has a normal distribution with mean of zero and variance of one. The chi-square test is a statistical test based on comparison of a test statistic to a chi-square distribution. The oldest of these tests are used to detect whether two or more population distributions differ from one another. (12 Dec 1998) |
| chi-square test | A statistical method of assessing the significance of a difference, as when the data from two or more samples is represented by a discrete number such as the numbers of females and males attending each of two colleges. Synonym: x2 test. (05 Mar 2000) |
| Chian turpentine | An exudation from Pistacia terebinthus, a small tree of Chios and regions eastward; on exposure to air it thickens and forms translucent yellow masses similar to mastic. Larch turpentine, a transparent, yellowish, thick liquid, the oleoresin obtained from Larix europaea (family Pinaceae). Synonym: Venice turpentine. (05 Mar 2000) |
| Chiari II syndrome | <syndrome> Elongation of medulla and cerebellar tonsils and vermis with displacement through the foramen magnum into the upper spinal canal; often associated with other cerebral anomalies. (05 Mar 2000) |
| Chiari's disease | <syndrome> Thrombosis of the hepatic vein with great enlargement of the liver and extensive development of collateral vessels, intractable ascites, and severe portal hypertension. Synonym: Budd's syndrome, Budd-Chiari syndrome, Chiari's disease, Chiari-Budd syndrome, Rokitansky's disease. (05 Mar 2000) |
| Chiari's net | Abnormal fibrous or lacelike strands in the right atrium, extending from the margins of the coronary or caval valves and attaching to the atrial wall along the line of the crista terminalis; results when resorption of the septum spurium is markedly less than normal. (05 Mar 2000) |
| Chiari's syndrome | <syndrome> Thrombosis of the hepatic vein with great enlargement of the liver and extensive development of collateral vessels, intractable ascites, and severe portal hypertension. Synonym: Budd's syndrome, Budd-Chiari syndrome, Chiari's disease, Chiari-Budd syndrome, Rokitansky's disease. (05 Mar 2000) |
| Chiari, Hans | <person> German pathologist, 1851-1916. See: Arnold-Chiari deformity, Arnold-Chiari malformation, Arnold-Chiari syndrome, Chiari's disease, Chiari's net, Chiari's syndrome, Chiari II syndrome, Chiari-Budd syndrome, Budd-Chiari syndrome. (05 Mar 2000) |