利他主义人口模型与性别差异的探讨

在单性利他主义理论研究的基础上，通过引入性别比率，建立新的数学模型，得到有着性别差异的的人口公式中利他主义进化的充分条件，从而说明雌性利他主义在利他主义的进化过程中所起的作用。     

Altruism and social cheating in the social amoeba Dictyostelium discoideum

The social amoeba, Dictyostelium discoideum, is widely used as a simple model organism for multicellular development, but its multicellular fruiting stage is really a society. Most of the time, D. discoideum lives as haploid, free-living, amoeboid cells that divide asexually. When starved, 10(4)-10(5) of these cells aggregate into a slug. The anterior 20% of the slug altruistically differentiates into a non-viable stalk, supporting the remaining cells, most of which become viable spores. If aggregating cells come from multiple clones, there should be selection for clones to exploit other clones by contributing less than their proportional share to the sterile stalk. Here we use microsatellite markers to show that different clones collected from a field population readily mix to form chimaeras. Half of the chimaeric mixtures show a clear cheater and victim. Thus, unlike the clonal and highly cooperative development of most multicellular organisms, the development of D. discoideum is partly competitive, with conflicts of interests among cells. These conflicts complicate the use of D. discoideum as a model for some aspects of development, but they make it highly attractive as a model system for social evolution.     

The order of the quantum chromodynamics transition predicted by the standard model of particle physics

Quantum chromodynamics (QCD) is the theory of the strong interaction, explaining (for example) the binding of three almost massless quarks into a much heavier proton or neutron--and thus most of the mass of the visible Universe. The standard model of particle physics predicts a QCD-related transition that is relevant for the evolution of the early Universe. At low temperatures, the dominant degrees of freedom are colourless bound states of hadrons (such as protons and pions). However, QCD is asymptotically free, meaning that at high energies or temperatures the interaction gets weaker and weaker, causing hadrons to break up. This behaviour underlies the predicted cosmological transition between the low-temperature hadronic phase and a high-temperature quark-gluon plasma phase (for simplicity, we use the word 'phase' to characterize regions with different dominant degrees of freedom). Despite enormous theoretical effort, the nature of this finite-temperature QCD transition (that is, first-order, second-order or analytic crossover) remains ambiguous. Here we determine the nature of the QCD transition using computationally demanding lattice calculations for physical quark masses. Susceptibilities are extrapolated to vanishing lattice spacing for three physical volumes, the smallest and largest of which differ by a factor of five. This ensures that a true transition should result in a dramatic increase of the susceptibilities. No such behaviour is observed: our finite-size scaling analysis shows that the finite-temperature QCD transition in the hot early Universe was not a real phase transition, but an analytic crossover (involving a rapid change, as opposed to a jump, as the temperature varied). As such, it will be difficult to find experimental evidence of this transition from astronomical observations.     

透过传统看传统

“传统”这一术语一直是民俗学研究领域中众多关键词之一。文章对民俗学界是否剖析过“传统”及传统是否作为一个用以帮助民俗学家感知、探索和解释世界的分析性范畴进行了九个方面的探讨,分别是：作为过程和产物的传统、传统与创造性、传统：客位和主位分析、传统与现代性、民俗与传统、作为当代主题的传统、传统的驱动力、传统研究的趋向以及传统的困境。分析指出：只有当民俗学家厘清传统的运行机制时,民俗学才能成为一门“传统科学”。     

关于人治与法治的哲学思考

人治与法治是矛盾着的两个方面,二者既互相对立,又互相统一,互为存在的前提,共处于统治方式这个统一体中,在人治产生的同时,也就有了法治的萌芽。随着社会的不断发展变化,人治逐渐为社会所抛弃,而法治因素却逐渐成长壮大,最终将取代人治。但是,法治对人治的否定不是全盘抛弃,而是辩证的否定,即扬弃。法治社会并不是不要人的主观能动性,相反,人的主观能动性显得十分重要,企图以有限的法条规范无限的客观法律事实和现象,把人当作法条操作机是不切实际的,也是十分幼稚的,法治社会的认本依然是人。     

从英汉差异看英语阅读

通过英汉语言对比,本文强调英文阅读要符合英文特点,避免汉语学习习惯的影响,"自上而下",从篇章到字词语法,培养语感,提高阅读效率。     

从DDT看绿色技术

从DDT看绿色技术闻名中外的化学杀虫剂———DDT,在20世纪的70年代以后,为什么在世界范围内被宣布停止使用了呢?答案是:只有从人类的整体和长远利益出发,着眼于生态平衡、资源再生、可持续发展,才能既实现环境价值又保证技术真正造福于人类自己。正是由于生态学规律的考量,生态技术或绿色技术的概念应运而生。     

通过收缩区的量子化电导

建立起一个由窄收缩区连接两个有限宽度电子库区组成的物理器件的突变模型．计算了通过收缩区的电导,由数字结果发现当收缩区的几何形状参数取适当值时,存在电导平台．     

运用化归 活化思维

阐述了化归法在化学教学中的运用,指出化归法是研究解决问题的一种逻辑思维方法,具有灵活的解题策略,能有效地提高解题速度．