Epicanthic fold Epicanthic fold The epicanthic fold is the skin fold of the upper eyelid, covering the inner corner (medial canthus) of the eye. Various factors influence whether epicanthic folds form, including ancestry, age, and certain medical conditions. The highest frequency of occurrence of epicanthic folds are found in: East Asians, Southeast Asians, Central Asians, North Asians, some South Asians, Polynesians, Micronesians, Indigenous Americans (as well as Mestizos), the Khoisan, Malagasy. In some of these populations the trait is almost universal. Epicanthic folds occur, but at considerably lower frequency, in: Europeans (e.g., Scandinavians, English, Irish, Hungarians, Russians, Poles, Lithuanians, Finns, Estonians and
Fold change ""X"-fold increase". As such, several dictionaries, including the Oxford English Dictionary and Merriam-Webster Dictionary, as well as Collins's Dictionary of Mathematics, define "-fold" to mean "times", as in "2-fold" = "2 times" = "double". Likely because of this definition, many scientists use not only "fold", but also "fold change" to be synonymous with "times", as in "3-fold larger" = "3 times larger".. More ambiguous is fold decrease, where, for instance, a decrease of 50% between two measurements would generally be referred to a "half-fold change" rather than a "2-fold decrease". Fold change is often used in analysis of gene expression