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。     

移动P2P中基于利他惩罚的合作保障机制

依据行为经济学中经大量实验验证的"非理性的"利他惩罚行为的存在,提出一种移动P2P系统中基于利他惩罚的合作保障机制——系统中存在非理性节点,即使得不到任何预期收益,为了追求公平,愿意付出一定成本惩罚自私节点的不合作行为,从而约束自私节点的行为,降低其不合作概率,促进节点的合作性.文中通过理论分析和仿真实验对该机制进行了验证,结果表明,利他惩罚保障节点合作是合理的,该机制能够有效地减少系统中自私节点的数量,降低系统的不合作程度.     

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.     

利他与合作:生物有机体的生存策略和进化路径

利他与合作是生物有机界普遍存在的现象．进一步研究表明,这类现象与经典的自然选择学说并不相悖,而是对其的进一步发展．利他与合作不过是生物有机体另一种不同的生存策略;利他与合作的进化也只是生物有机体为适应环境而形成的另一条不同的进化路径．     

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。     

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”。     

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。     

穿过瓶颈的写作

合上<乌鸦>,不由得想到另一个故事<乌鸦喝水>.这样的念头并不是因为题目雷同所引发的自由联想,而是隐藏在这两个看起来毫不相干的故事背后某些类似的东西直接触动了我.     

Electrical conduction through DNA molecules

The question of whether DNA is able to transport electrons has attracted much interest, particularly as this ability may play a role as a repair mechanism after radiation damage to the DNA helix. Experiments addressing DNA conductivity have involved a large number of DNA strands doped with intercalated donor and acceptor molecules, and the conductivity has been assessed from electron transfer rates as a function of the distance between the donor and acceptor sites. But the experimental results remain contradictory, as do theoretical predictions. Here we report direct measurements of electrical current as a function of the potential applied across a few DNA molecules associated into single ropes at least 600 nm long, which indicate efficient conduction through the ropes. We find that the resistivity values derived from these measurements are comparable to those of conducting polymers, and indicate that DNA transports electrical current as efficiently as a good semiconductor. This property, and the fact that DNA molecules of specific composition ranging in length from just a few nucleotides to chains several tens of micrometres long can be routinely prepared, makes DNA ideally suited for the construction of mesoscopic electronic devices.     

由非典看当今环境问题

阐述了当今环境问题及这些环境问题的根源和危害，倡导人类要在维护大自然生态平衡和良好环境的前提下进行生产、生活，从而为人类提供一个健康的生活空间。