Molecular mechanisms that confer antibacterial drug resistance

Antibiotics--compounds that are literally 'against life'--are typically antibacterial drugs, interfering with some structure or process that is essential to bacterial growth or survival without harm to the eukaryotic host harbouring the infecting bacteria. We live in an era when antibiotic resistance has spread at an alarming rate and when dire predictions concerning the lack of effective antibacterial drugs occur with increasing frequency. In this context it is apposite to ask a few simple questions about these life-saving molecules. What are antibiotics? Where do they come from? How do they work? Why do they stop being effective? How do we find new antibiotics? And can we slow down the development of antibiotic-resistant superbugs?     

The plant immune system

Many plant-associated microbes are pathogens that impair plant growth and reproduction. Plants respond to infection using a two-branched innate immune system. The first branch recognizes and responds to molecules common to many classes of microbes, including non-pathogens. The second responds to pathogen virulence factors, either directly or through their effects on host targets. These plant immune systems, and the pathogen molecules to which they respond, provide extraordinary insights into molecular recognition, cell biology and evolution across biological kingdoms. A detailed understanding of plant immune function will underpin crop improvement for food, fibre and biofuels production.     

三峡工程论证决策过程及其实践检验

举世瞩目的三峡水利枢纽工程是世界上规模最大的水电站,也是中国有史以来建设的最大型水利水电工程。2010年10月26日,三峡水库蓄水首次达到设计水位175 m,这标志着其防洪、发电、航运等各项功能达到设计要求。三峡工程从构想、论证、设计、建设至竣工全面投入运行历时近百年。当初兴建三峡工程的构想是如何提出的？三峡工程究竟起什么作用？存在什么分歧意见？是如何进行论证的？论证的结论怎样？这是许多人关心而又不太了解的,笔者在文中做了扼要的介绍,以纪念世纪之梦的实现。     

现代工业设计的走向问题探讨

现代工业设计走过百年的历程,设计的方向逐渐出现了分岔和偏离。我们应该怎样看待我们周围生活中的设计,周围的人,以及生活的品位,休闲娱乐的方式和对社会价值的认知。工业设计的发展何去何从?设计的统筹规划究竟该如何进行?它该如何向提升人的价值品位和生活质量的设计方向发展。     

高职艺术设计类"双师型"教师培养途径的探索与实践

一、问题的提出进入21世纪以来,经济全球化来势迅猛,中国产品正遭遇到来自国际市场上的反倾销壁垒的阻击和国内市场上国际知名品牌大举入侵的双重压力。目前,我国企业过多地依赖廉价劳动力这种单一竞争手段,缺乏品牌意识,产品核心竞争力弱。其粗放型的生产方式导致我国产品有处     

基于Ontology的语义Web知识获取

如何在web上设计更好的检索技术？如何为Web上的资源附加计算机可以理解的内容？这是web应用的前沿课题，本文论述了Ontology及其在语义Web知识获取中的重要性，提出了基于Ontology的语义Web知识获取的模型，并对一种基于语义Web的信息检索模型进行了探讨，给出了实验结果证明了该方法的有效性和可行性。     

泰北华人村华语状态及教育情况调查报告

泰北华人村是一个极为特殊而尴尬的华人聚集区,本文利用国家侨办组织赴泰北进行汉语教师培训的机会,对该地华语使用情况和华文教育情况进行了一些初步的调查和分析。由于外界因素的影响,该地华语的使用情况已经发生了许多变化;由于条件的限制,该地的华文教育还相当落后。希望本文能引起各界人士和专家对该群体的更多关注。     

基于企业管理人员素质的诺兰模型应用研究

ERP平台的应用是企业信息化的主要内容。本从企业用户的角度出发,用诺兰模型分析和数理统计定量化分析相结合的方法,提出了我国企业ERP项目规划阶段进行自我评审的基于管理人员素质的切实可行的X—诺兰模型战略规划理论及相应的操作技术,同时,也从计算机系统技术角度给出了各种方案的具体解决对策。     

Variation in the reversibility of evolution

How reversible is adaptive evolution? Studies of microbes give mixed answers to this question. Reverse evolution has been little studied in sexual populations, even though the population genetics of sexual populations may be quite different. In the present study, 25 diverged replicated populations of Drosophila melanogaster are returned to a common ancestral environment for 50 generations. Here we show that reverse evolution back to the ancestral state occurs, but is not universal, instead depending on previous evolutionary history and the character studied. Hybrid populations showed no greater tendency to undergo successful reverse evolution, suggesting that insufficient genetic variation was not the factor limiting reverse evolution. Adaptive reverse evolution is a contingent process which occurs with only 50 generations of sexual reproduction.     

A simple game for the study of trust in distributed systems

Trust is an important aspect of the design and analysis of secure distributed systems. It is often used informally to designate those portions of a system that must function correctly in order to achieve the desired outcome. But it is a notoriously diffcult notion to formalize. What are the properties of trust? How is it learned, propagated, and utilized successfully? How can it be modeled? How can a trust model be used to derive protocols that are effcient and reliable when employed in today’s expansive networks? Past work has been concerned with only a few of these issues, without concentrating on the need for a comprehensive approach to trust modeling. In this paper, we take a first step in that direction by studying an artificial community of agents that uses a notion of trust to succeed in a game against nature. The model is simple enough to analyze and simulate, but also rich enough to exhibit phenomena of real-life interactive communities. The model requires agents to make decisions. To do well, the agents are informed by knowledge gained from their own past experience as well as from the experience of other agents. Communication among agents allows knowledge to propagate faster through the network, which in turn can allow for a more successful community. We analyze the model from both a theoretical and an experimental point of view.     

Man-made antibodies

Monoclonal antibodies can now be genetically engineered and endowed with new properties. In the future, gene technology could enable antigen-binding fragments to be made by exploiting repertoires of variable domain genes derived from immunized animals and expressed in bacteria. How readily can this approach be extended to production of 'in vitro' repertoires of variable domain genes, and obviate the immunization of animals?     

面向信息时代的一种数学教学模式

21世纪人类进入了信息时代,以计算机为核心的现代教育技术的不断发展,已经改变了数学教育单一的教学模式、但是,如何利用网络资源支持教师的教学,帮助学生的学习,使技术和教学达到有机的整合,从而使数学教育方式发生根本性的变革,Webquest教学模式提供了一种思路．     

开发应用程序用户界面设计的基本原则

目前，Microsoft公司的很多应用程序被广泛使用，原因之一是这些应用程序有一个共同的特点：好的用户界面。那么，什么是好的用户界面?我们在开发自己的软件时，又怎样尽快的、更好的设计出用户界面?本文从七个方面介绍了利用可视化的程序设计语言设计应用程序界面的原则及技巧，并给出了一些实际设计的例子。     

偏序集与不同种广义拟阵间的包含关系

众所周知,偏序集理论在研究广义拟阵论中起着重要作用.但是偏序集理论与不同种广义拟阵间的包含关系的直接联系是什么呢?怎样运用偏序集理论的手法去解决该问题呢?为得到答案,首先对于定义在同一集上的全体广义拟阵构造一个偏序关系,运用这种偏序关系讨论不同种的广义拟阵间的包含关系.多数结论是以构造方式给出,因此也使其在理论和运用方面更加简捷明了.     

文件系统浅谈

文件系统是指文件命名、存储和组织的总体结构。自微软推出Window　XP后 ,很多用户在安装WindowXP时都遇到了一个难题 ,文件系统选择FAT3 2还是选择NTFS ,微软的建议是NTFS,但二者有何区别 ,各种文件系统又如何相互转换和互访 ,本文就此介绍一些有关文件系统的理论知识和实用技巧     

初中化学用语的教学策略

化学用语是学习化学的重要工具，它贯串于中学化学教材的始终，但化学用语也常常成为初中化学学习的难点。怎样才能使学生学好化学用语?这里，笔着重探讨初中化学用语的教学策略。     

谈"绿色"化学实验室的建设

在高等院校，化学实验室每天排放成分复杂的没有进行处理的废弃物，这些废弃物中含有的有害物质，对环境造成了污染。本文就如何减少实验室污染物的排放，如何消除环境污染，倡导建设绿色化学实验室，谈了自己的认识。     

我国传统企业选择电子商务的模式

电子商务的发展使社会经济发生了巨大的变化 ,网络经济可能成为未来经济发展的主流 ,传统企业如何面对网络经济的挑战 ,如何适应这种转变 ,成为当前普遍关心的问题。本文对我国的电子商务发展现状进行了深层的分析 ,并对传统企业介入电子商务的模式进行了分析和探讨     

程序设计实验教学探讨

学习程序设计,重在上机练习,但对每周仅有的一次实验课,教师应如何安排?才能使其充分发挥作用.本文针对《程序设计》课程的特点,遵循"学生为主体,教师为主导"的现代教学指导思想,提出"质量兼顾,备验一体,总结巩固,评价保障"的实验课教学方针,充分调动学生的学习积极性,达到举一反三,事半功倍的效果.     

如何界定会计信息失真

会计信息是广大投资者(包括潜在投资者)、债权人、经理人和有关政府部门等各自作出相应经济决策的重要依据,信息失真理所当然地成为他们关注的热点问题。究竟什么是会计信息失真?判断会计失真的标准和依据是什么?会计信息真实性与公允性、重要性存在什么样的关系?与会计差错、会计虚假、会计认定存在什么逻辑关系?这些问题是本文要深入分析、讨论和揭示的重点。