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The optimal sex ratio in cooperatively breeding populations

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Chinese Science Bulletin 2014年第35期59卷 5074-5079页

作者： Yaqiang Wang Yaotang Li Ruiwu Wang School of Mathematics and Statistics Yunnan University State Key Laboratory of Genetic Resources and Evolution EcologyConservationand Environment CenterKunming Institute of ZoologyChinese Academy of Sciences

In some cooperatively breeding species,elder siblings remain within their home ranges to assist their parents in raising their younger siblings by providing protection or *** attempts to model the population sex ratios of such species have assumed that helping is cost-free and only involves benefits to parents,resulting in offspring sex ratio biases towards the helping ***,parents may also incur costs in maintaining *** incorporated costs and benefits of helping to predict the sex ratio of offspring in a theoretical *** model showed that the evolutionary stable strategy(ESS)sex ratio strongly depends on three parameters:(1) the average number of helpers per female;(2) the benefits that a helper brings to its mother's offspring production(MOP);and(3) the cost-benefit ratio of *** one sex of elder siblings provides help,the ESS sex ratio is biased towards the helping sex if MOP costs are less than the benefits,(i.e.,the cost-benefit ratio \1).However,the ESS sex ratio becomes biased towards the non-helping sex if MOP costs exceed the benefits(i.e.,the cost-benefit ratio [1).Additionally,our model shows that the ESS sex ratio becomes biased in favor of the more helpful sex when both male and female elder siblings provide *** results explain why sex ratios may become biased towardsthe helping sex,as well as the non-helping sex,in some species.

关键词：性别比例育种群体成本效益协作进化稳定策略模型显示 ESS MOP

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Cooperation in an asymmetric volunteer's dilemma game with relatedness

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Chinese Science Bulletin 2012年第16期57卷 1972-1981页

作者： HE JunZhou WANG RuiWu CHRISTOPHER X J Jensen LI YaoTang LI ChaoQian School of Mathematics and Statistics Yunnan UniversityKunming 650091China State Key Laboratory of Genetic Resources and Evolution Kunming Institute of ZoologyChinese Academy of SciencesKunming 650223China Department of Mathematics and Science School of Liberal Arts and SciencesPratt Institute200 Willoughby AvenueBrooklynNY 11205USA

What motivates some members of a social group to voluntarily incur costs in order to provide for the common good? This question lies at the heart of theoretical and empirical studies of cooperative behavior. This is also the question that underlies the classic volunteer's dilemma model, which has been previously explored in scenarios where group members are related or interact asym- metrically. Here we present a model that combines asymmetry and relatedness, showing that the probability of volunteerism in such systems depends closely on both the degree of asymmetry and level of relatedness between interacting individuals. As has been shown in previous volunteer's dilemma models, the payoff ratio and overall group size also influence the probability of volunteerism. The probability of volunteerism decreases with increasing group size or decreasing cost-to-benefit ratio of the coplayers; in the presence of asymmetrical interactions, subordinate players were more likely to offer public goods than the dominant player. More asymmetrical interactions decrease the probability of volunteerism of the dominant player; overall volunteerism increases with increasing relatedness.

关键词：不对称性志愿者关联性合作游戏相互作用社会团体关联程度

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广义对角占优矩阵的判定准则

高等学校计算数学学报 2012年第1期34卷 23-29页

作者：王峰菏泽学院数学系

1引言广义对角占优矩阵在理论上和应用上都十分重要,它的研究已广泛引起人们的注意.最近,许多文章都在寻求它的简单实用的判别([1-8]).本文在文[1-7]的基础上,讨论了广

关键词： generalized diagonally dominant matrix strictly diagonally dominant matrix irreducibility chain of nonzero elements

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电子商务平台间LV竞争模型研究及其解释

商业研究 2014年第6期 37-41页

作者：叶琼伟强欣宋光兴云南财经大学商学院昆明650221

20世纪90年代以来,电子商务作为一种新兴的商务模式迅速发展,同时电子商务平台企业相互间的竞争也不断加剧,厘清其背后的竞争机理显得尤为重要和紧迫。本文引入生物物种的Lotka-Volterra种间竞争模型,建立了单一电子商务平台企业(初创... 详细信息

20世纪90年代以来,电子商务作为一种新兴的商务模式迅速发展,同时电子商务平台企业相互间的竞争也不断加剧,厘清其背后的竞争机理显得尤为重要和紧迫。本文引入生物物种的Lotka-Volterra种间竞争模型,建立了单一电子商务平台企业(初创企业或垄断企业)、双电子商务平台企业及多个电子商务平台企业的LV竞争模型,分析基于双边市场的电子商务平台企业间的竞争关系,从经济学角度对基于双边市场的LV模型作出了解释,并给出了相应的政策建议。

关键词：电子商务 LV种间竞争模型双边市场平台企业

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