Evolution of animal personalities

Wolf et al. propose a model to explain the existence of animal personalities, consistent with behavioural differences among individuals in various contexts--their explanation is counter-intuitive and cogent. However, all models have their limits, and the particular life-history requirements of this one may be unclear. Here we analyse their model and clarify its organismal scope.     

Dynamic personalities of proteins

Because proteins are central to cellular function, researchers have sought to uncover the secrets of how these complex macromolecules execute such a fascinating variety of functions. Although static structures are known for many proteins, the functions of proteins are governed ultimately by their dynamic character (or 'personality'). The dream is to 'watch' proteins in action in real time at atomic resolution. This requires addition of a fourth dimension, time, to structural biology so that the positions in space and time of all atoms in a protein can be described in detail.     

体育教学与学生的个性培养

体育教学与学生个性培养密切相关,围绕健康的个性,从心理特征和个性倾向性两方面入手,在能力、气质、性格、兴趣、需要、动机、信念等几个方面探讨体育教学与个性培养的关系,旨在体育教学中创造良好的个性发展空间,达到发展学生健康个性的目的.     

Metabolic trade-offs and the maintenance of the fittest and the flattest

How is diversity maintained? Environmental heterogeneity is considered to be important, yet diversity in seemingly homogeneous environments is nonetheless observed. This, it is assumed, must either be owing to weak selection, mutational input or a fitness advantage to genotypes when rare. Here we demonstrate the possibility of a new general mechanism of stable diversity maintenance, one that stems from metabolic and physiological trade-offs. The model requires that such trade-offs translate into a fitness landscape in which the most fit has unfit near-mutational neighbours, and a lower fitness peak also exists that is more mutationally robust. The 'survival of the fittest' applies at low mutation rates, giving way to 'survival of the flattest' at high mutation rates. However, as a consequence of quasispecies-level negative frequency-dependent selection and differences in mutational robustness we observe a transition zone in which both fittest and flattest coexist. Although diversity maintenance is possible for simple organisms in simple environments, the more trade-offs there are, the wider the maintenance zone becomes. The principle may be applied to lineages within a species or species within a community, potentially explaining why competitive exclusion need not be observed in homogeneous environments. This principle predicts the enigmatic richness of metabolic strategies in clonal bacteria and questions the safety of lethal mutagenesis as an antimicrobial treatment.     

Life-history traits of voles in a fluctuating population respond to the immediate environment.

Life-history traits relating to growth and reproduction vary greatly among species and populations and among individuals within populations. In vole populations, body size and age at maturation may vary considerably among locations and among years within the same location. Individuals in increasing populations are typically larger and start reproduction earlier in the spring than those in declining populations. The cause of such life-history variation within populations has been subject of much discussion. Much of the controversy concerns whether the memory of past conditions, leading to delayed effects on life-history traits, resides in the environment (for example, predators, pathogens or food) or intrinsically within populations or individuals (age distribution, physiological state, genetic or maternal effects). Here we report from an extensive field transplant experiment in which voles were moved before the breeding season between sites that differed in average overwintering body mass. Transplanted voles did not retain the characteristics of their source population, and we demonstrate an over-riding role of the immediate environment in shaping life-history traits of small rodents.     

鹅掌楸生殖生态研究:生殖分配与生活史对策

在鹅掌楸的营养生长和生殖两方面．资源不平衡分配。生殖和营养结构发育所需的资源位在时间上重叠。生殖包装和生殖分配格局显示．大种子稍优于小种子,资源被部分地用于提高种子散布适合度,资源限制结籽率假说不适合该树种。鹅掌楸的生活史特征表现为：初次结实年龄10a以上,为多次结实,可大量结实,种子中等大小;植物个体寿命达100a以上．有性生殖过程持续时间长。从生活史特征组合分析可知,鹅掌楸是需要迁移的种(即r-对策)。     

论时间／费用优化中资金的时间价值

以时间/费用优化为例,给出了考虑资金时间价值后,对网络进行动态时间/费用优化的数学模型,编制了遗传算法程序,通过改进的遗传算法求取了模型的最优解,并且将优化结果与不考虑资金时间价值条件下的结果进行分析对比,结果表明,考虑资金的时间价值对网络进行动态优化其结果才更为可靠、准确.     

高职高专院校体育专业学生的人格分析

使用卡特尔十六项人格因素量表（16PF）对高职高专院校体育专业学生的个性进行测量与分析，总结高职高专院校体育专业学生的个性特点，并从高职高专院校体育专业学生管理的角度提出建议。     

引起动物福利伦理争议的动物实验

 基础医学研究、药物研发、医疗器械评价等均会涉及实验动物和动物实验,国际上已经把实验动物科学条件和动物福利管理作为衡量一个国家科学技术现代化水平的标志。本文分析了近年引发国内外动物福利伦理争议的动物实验。     

动物源性食品安全分析

肉、蛋、奶等是人类动物源性食品,直接关系到人的身体健康．动物养殖过程中的疫病防控、兽药残留、饲料及饮水卫生等是影响动物源性食品卫生质量的关键环节,只有严格控制这三个重要环节,才能保障动物原性食品安全．