منابع مشابه
Power and potential bias in field studies of natural selection.
The advent of multiple regression analyses of natural selection has facilitated estimates of both the direct and indirect effects of selection on many traits in numerous organisms. However, low power in selection studies has possibly led to a bias in our assessment of the levels of selection shaping natural populations. Using calculations and simulations based on the statistical properties of s...
متن کاملSelection Bias
data in Haneuse et al. [1] . The risk ratio of dementia by exposure in the total target population is 2.0, and is the true association (there is no confounding in our simple DAG; fig. 1 ). Table 1 shows the expected distribution by exposure and outcome by strata of dead/alive under the following assumptions: half of the population dies; there is a risk ratio of death for the exposed compared to...
متن کاملSelection Bias, Label Bias, and Bias in Ground Truth
Language technology is biased toward English newswire. In POS tagging, we get 97–98 words right out of a 100 in English newswire, but results drop to about 8 out of 10 when running the same technology on Twitter data. In dependency parsing, we are able to identify the syntactic head of 9 out of 10 words in English newswire, but only 6–7 out of 10 in tweets. Replace references to Twitter with re...
متن کاملSelection on codon bias.
In a wide variety of organisms, synonymous codons are used with different frequencies, a phenomenon known as codon bias. Population genetic studies have shown that synonymous sites are under weak selection and that codon bias is maintained by a balance between selection, mutation, and genetic drift. It appears that the major cause for selection on codon bias is that certain preferred codons are...
متن کاملNatural selection
The time-scale of evolution Think of the 3.5 billion years that makes the history of life on earth as stretching for a single year. On the first of January, there is nothing more than primitive bacteria, and this remains the case for the next eight months. Multicellular eukaryotic life appears in early September, vertebrates invade the land at the beginning of December and dinosaurs become exti...
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ژورنال
عنوان ژورنال: Nature
سال: 1997
ISSN: 0028-0836,1476-4687
DOI: 10.1038/386234b0