heterogeneity n : the quality of being diverse and not comparable in kind [syn: heterogeneousness] [ant: homogeneity]
Heterogeneous is an adjective used to describe something that has a large amount of variants or different forms. Derived from the Greek; heteros or 'other' and genos or 'kind'. It is the antonym of homogeneous, which means that an object or system consists of many identical items. Matters of a quantum can exist in homogenous or in heterogeneous or in combined distributions. The term is often used in a scientific (such as a kind of catalyst), mathematical, sociological or statistical context.
A heterogeneous compound, mixture, reaction or other such object is one that consists of many different items, which are often not easily sorted or separated, though they are clearly distinct.
A heterogeneous mixture is a mixture of two or more compounds. In chemical kinetics, a heterogeneous reaction is one that takes place at the interface of two or more i.e. between a solid and a gas, a liquid and a gas, or a solid and a liquid.
= Statistics =
In meta analysis the term refers to the presence of multiple non-random intercepts in a dataset. In Meta-analysis of clinical studies which involves comparing and quantifying the effects of separate studies, heterogeneity refers to the differences in study populations or in methodologies used to study them that may have the effect of reaching differing conclusions. This is a problem as it calls into question conclusions that are drawn from studies and reduces their comparability. The following concepts are important in understanding the importance of heterogeneity in meta-analytical research.
Heterogeneity resulting from differences in clinical features of a population that is being studied or treated.
Heterogeneity resulting from the differential use of study methodology. These may lead to different conclusions in different studies, despite their clinical characteristics being the same.
Heterogeneity resulting from either clinical or statistical heterogeneity, which leads to a difference in expected results, more than which can be accounted for by chance.
In the world of enterprise computing, heterogeneous data is a mix of data from two or more sources, often of two or more formats, e.g., SQL and XML.
Distributed systems are called heterogeneous if they contain many different types of hardware and software.
See alsoDistributed computing
Social and human scienceHomogeneity and heterogeneity are terms used to describe variety in many aspects of human groups, communities and populations, including cultural, demographic, ethnic and socio-political. In Economics and Social Sciences, 'heterogeneous agents' refers to a set of agents with different properties. The opposite of 'heterogeneous agents' in economic terminology is 'representative agent'.
In taxonomy, a heterogeneous taxon is a taxon that contains a great variety of individuals or sub-taxa; usually this implies that the taxon is an artificial grouping.
In genetics, heterogeneity refers to multiple origins causing the same disorder in different individuals.
If a number of different mutations occurring the same gene produce disorders, it is said to manifest allelic heterogeneity. This term has been used when a number of different alleles cause a similar phenotype or different phenotypes.
- Different FBN1 mutations causing Marfan's syndrome
- Cystic fibrosis is cause by greater than 900 different mutant alleles.
- Alpha-Thalassemia or sickle cell anemia can be caused by different mutations in alpha-globin gene.
Locus (Non-allelic) Heterogeneity
If mutations at a number of different loci of the same gene, or mutations involving different genes, all result in the same disorder, such disorder is said to manifest locus heterogeneity.
- Retinitis Pigmentosa has autosomal dominant, autosomal recessive, and x-linked origins.
heterogeneity in Arabic: متغاير
heterogeneity in Czech: Heterogennost
heterogeneity in German: Heterogenität
heterogeneity in Spanish: Sistema heterogéneo
heterogeneity in Hebrew: הטרוגניות
heterogeneity in Russian: Гетерогенная система
heterogeneity in Slovenian: Heterogen
heterogeneity in Turkish: Heterojen