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In this article the author offers an original interpretation of patterns found on the world's most ancient felts (Fifth Century BCE). These artifacts have been recovered from frozen burial mounds in the Altai Mountains. The interpretation presented here constitutes a new approach to the study of ornamentation as a system of symbols.  相似文献   

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Heterosis or Neutrality?   总被引:12,自引:3,他引:9       下载免费PDF全文
G. A. Watterson 《Genetics》1977,85(4):789-814
Various statistics have been proposed on an ad hoc basis to test whether alleles at a locus are selectively neutral. By considering population models in which selection operates, this paper shows that the population homozygosity is a powerful test statistic for testing departures from neutrality, in the direction of heterozygote advantage or disadvantage. The sample homozygosity plays a similar role when only sample data are available. Some numerical examples are included, showing the application of the test.—An analysis is made of the effect of heterosis on such quantities as the expected number of alleles in the population or sample, the effective number of alleles, the expected homozygosity, and on the population and sample allele frequency distributions generally.  相似文献   

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Bonobo, the Forgotten Ape by F. de Waal University of California Press, 1997. £39.95 hbk (210 pages) ISBN 0 520 20535 9.  相似文献   

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《BMJ (Clinical research ed.)》1954,2(4901):1406-1407
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The process of dissimilatory metal reduction shapes our environment on a global scale by using minerals as terminal acceptors in a biological electron transport chain employed by bacteria under anaerobic conditions. In this issue of Structure, Edwards et?al. present the structure of an extracellular undecaheme cytochrome involved in the step of electron transfer to metal oxides.  相似文献   

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Hyperbole has become a common and accepted practice in science nowadays. We sell our results, we hide our ignorance and we use stock terms that gain spurious weight through repeated use. I illustrate from the field of developmental genetics.  相似文献   

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