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1.
Genetic variations within and between troops of the Indonesian crab-eating macaque (Macaca fascicularis) were studied. A total of 456 blood samples were collected from 29 free-ranging troops in 19 different localities on Sumatra,
Java, Bali, Lombok and Sumbawa. Blood protein polymorphisms were examined electrophoretically. Mean genetic variability within
troops was estimated to be Ppoly=12.22% and
=3.84%. Troops inhabiting small islands showed lower variability. Genetic differences were more marked between troops on different
islands than between troops on the same island. Additionally, clinal variations of allelic frequencies at some loci were detected.
The genetic features and socio-ecological and evolutionary implications are discussed. 相似文献
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In this paper we present a deterministic, discrete-time model for a two-patch predator-prey metapopulation. We study optimal
harvesting for the metapopulation using dynamic programming. Some rules are established as generalizations of rules for a
single-species metapopulation harvesting theory. We also establish rules to harvest relatively more (or less) vulnerable prey
subpopulations and more (or less) efficient predator subpopulations. 相似文献
4.
In this paper, we discuss a two-age-classes dengue transmission model with vaccination. The reason to divide the human population into two age classes is for practical purpose, as vaccination is usually concentrated in one age class. We assume that a constant rate of individuals in the child-class is vaccinated. We analyze a threshold number which is equivalent to the basic reproduction number. If there is an undeliberate vaccination to infectious children, which worsens their condition as the time span of being infectious increases, then paradoxically, vaccination can be counter productive. The paradox, stating that vaccination makes the basic reproduction number even bigger, can occur if the worsening effect is greater than a certain threshold, a function of the human demographic and epidemiological parameters, which is independent of the level of vaccination. However, if the worsening effect is to increase virulence so that one will develop symptoms, then the vaccination is always productive. In both situations, screening should take place before vaccination. In general, the presence of class division has obscured the known rule of thumb for vaccination. 相似文献
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Shi Yu Tillmann Falck Anneleen Daemen Leon-Charles Tranchevent Johan AK Suykens Bart De Moor Yves Moreau 《BMC bioinformatics》2010,11(1):309
Background
This paper introduces the notion of optimizing different norms in the dual problem of support vector machines with multiple kernels. The selection of norms yields different extensions of multiple kernel learning (MKL) such as L ∞, L 1, and L 2 MKL. In particular, L 2 MKL is a novel method that leads to non-sparse optimal kernel coefficients, which is different from the sparse kernel coefficients optimized by the existing L ∞ MKL method. In real biomedical applications, L 2 MKL may have more advantages over sparse integration method for thoroughly combining complementary information in heterogeneous data sources. 相似文献8.
The Indian black berry (Syzygium cumini Skeels) has a great nutraceutical and medicinal properties. As in other fruit crops, the
fruit characteristics are important attributes for differentiation were also determined for different accessions of S. cumini. The fruit
weight, length, breadth, length: breadth ratio, pulp weight, pulp content, seed weight and pulp: seed ratio significantly varied in
different accessions. Molecular characterization was carried out using PCR based RAPD technique. Out of 80 RAPD primers, only
18 primers produced stable polymorphisms that were used to examine the phylogenetic relationship. A sum of 207 loci were
generated out of which 201 loci found polymorphic. The average genetic dissimilarity was 97 per cent among jamun accessions.
The phylogenetic relationship was also determined by principal coordinates analysis (PCoA) that explained 46.95 per cent
cumulative variance. The two-dimensional PCoA analysis showed grouping of the different accessions that were plotted into four
sub-plots, representing clustering of accessions. The UPGMA (r = 0.967) and NJ (r = 0.987) dendrogram constructed based on the
dissimilarity matrix revealed a good degree of fit with the cophenetic correlation value. The dendrogram grouped the accessions
into three main clusters according to their eco-geographical regions which given useful insight into their phylogenetic
relationships. 相似文献
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不同耕作措施对冬小麦-夏玉米复种连作系统土壤有机碳和水分利用效率的影响 总被引:2,自引:1,他引:1
在连续8年田间定位试验的基础上,分析了关中平原冬小麦 夏玉米复种连作系统2008—2009年连续两个生长季期间不同耕作措施(结合秸秆还田和不还田)对土壤有机碳和水分利用率的影响.结果表明: 相对于传统耕作,保护性耕作有利于土壤有机碳、水分利用效率和作物产量的提高,其中在“深松+秸秆还田”耕作模式下的增幅最高,土壤有机碳含量在0~30 cm土层增幅达到19.5%,水分利用效率和作物产量提高了16.9%和20.5%,而免耕模式则有效提高了0~10 cm土层有机碳含量.在该地区土壤和气候条件下,深松结合秸秆粉碎还田是最理想的耕作模式,最有利于土壤有机碳累积,并提高水分利用效率和作物产量. 相似文献
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