Predictive models of molecular machines involved in Caenorhabditis elegans early embryogenesis

Although numerous fundamental aspects of development have been uncovered through the study of individual genes and proteins, system-level models are still missing for most developmental processes. The first two cell divisions of Caenorhabditis elegans embryogenesis constitute an ideal test bed for a system-level approach. Early embryogenesis, including processes such as cell division and establishment of cellular polarity, is readily amenable to large-scale functional analysis. A first step toward a system-level understanding is to provide 'first-draft' models both of the molecular assemblies involved and of the functional connections between them. Here we show that such models can be derived from an integrated gene/protein network generated from three different types of functional relationship: protein interaction, expression profiling similarity and phenotypic profiling similarity, as estimated from detailed early embryonic RNA interference phenotypes systematically recorded for hundreds of early embryogenesis genes. The topology of the integrated network suggests that C. elegans early embryogenesis is achieved through coordination of a limited set of molecular machines. We assessed the overall predictive value of such molecular machine models by dynamic localization of ten previously uncharacterized proteins within the living embryo.     

JOINTLESS is a MADS-box gene controlling tomato flower abscission zone development

Abscission is a universal and dynamic process in plants whereby organs such as leaves, flowers and fruit are shed, both during normal development, and in response to tissue damage and stress. Shedding occurs by separation of cells in anatomically distinct regions of the plant, called abscission zones (AZs). During abscission, the plant hormone ethylene stimulates cells to produce enzymes that degrade the middle lamella between cells in the AZ. The physiology and regulation of abscission at fully developed AZs is well known, but the molecular biology underlying their development is not. Here we report the first isolation of a gene directly involved in the development of a functional plant AZ. Tomato plants with the jointless mutation fail to develop AZs on their pedicels and so abscission of flowers or fruit does not occur normally. We identify JOINTLESS as a new MADS-box gene in a distinct phylogenetic clade separate from those functioning in floral organs. We propose that a deletion in JOINTLESS accounts for the failure of activation of pedicel AZ development in jointless tomato plants.     

混沌扩频序列构造算法的完善

混沌扩频序列在未来的扩展频谱通信领域将发挥出巨大的潜力,通过分析混沌序列仿真的双精度浮点算法,以Logistic映射为例就初始值的选取、临界值的修订、伪周期问题处理等提出了完善并优化混沌序列性能的方法。     

全局Poisson抠图的实现与改进

数字抠图技术是一种把图像的前景部分从背景中分离出来的一种技术,它在电影、电视等视频制作中得到了广泛的应用。文章主要目的是对Poisson抠图方法进行改进,以取得更好的处理效果或更快的处理速度。首先对Poisson抠图技术进行了简单的介绍,并对它的实现过程进行了描述。最后,用区域生长的方法对全局Poisson抠图进行了改进,减少了算法的执行时间。     

多机系统中电力系统稳定器与可控串联补偿器阻尼控制器的协调设计

针对电力系统稳定器（power system stabilizer，PSS）和可控串联补偿器（thyristor controlled series compensators，TCSC）的附加阻尼控制器能分别有效阻尼机间振荡和区域振荡的特点，提出一种采用单纯形-模拟退火法对PSS和TCSC阻尼控制器进行协调优化的设计方法．该方法结合单纯形算法局部搜索速度快和模拟退火算法全局搜索能力强的优点，将单纯形算法作为模拟退火算法的局部寻优算子，以增强算法的搜索能力和效率．同时，优化中使用的目标函数考虑了系统多种典型运行方式下的机电振荡模态性能，因而设计出的阻尼控制器具有较强的鲁棒性．在4机11节点电力系统上运用该优化方法完成了阻尼控制器的协调设计．特征值分析和非线性时域仿真结果显示，使用该方法设计的PSS和TCSC阻尼控制器对不同的运行方式都能有效抑制系统低频振荡．此外，算例分析结果证实了单纯形-模拟退火算法搜寻能力高、不强烈依赖初始值选择的优点。     

锥模和弧形模芯拔管成型过程的非线性有限元分析

管材拉拔主要有空拔、固定短芯棒拉拔、长芯棒拉拔、游动芯棒拉拔、顶管法以及扩径拉拔等方法.与空拔相比,芯棒拔管具有许多优点(变形均匀、残余应力低及钢管壁厚精度高等),其中固定短芯棒拉拔应用最广泛.固定短芯棒拉拔就是在拉拔时,芯棒通过一个与机架尾部相连的拉杆被固定在     

崇明“农家乐”旅游发展面临的困境及对策

经过近6年的发展，崇明“农家乐”旅游在经济、社会和环境效益等方面都取得了一定的收获．然而，由于在旅游软硬件建设上的欠缺和薄弱，“农家乐”旅游却遇到了很多问题，其进一步发展受到很大限制．作者根据对岛内“农家乐”旅游实地调查所掌握的客观情况，对其目前发展所面临的主要问题进行了分析研究；在此基础上阐释了如何摆脱这些困境的对策和措施．     

中国企业伦理存在的问题及对策

中国企业在计划经济转型为社会主义市场经济过程中,带来了社会进步,但也带来了许多企业伦理问题。本文重点分析了经济转型中的企业伦理缺失、企业诚信缺失和环境污染三个伦理问题并提出了解决对策。     

“体育经纬”专栏专家委员会名单

在第三次全教会明确指出的“学校教育要树立健康第一”的指导思想指导下,根据新的《全国普通高等学校体育课程教学指导纲要》精神,针对合校后,新建综合性大学多校区运转体育教学的现状与实际,以及普通大学公修体育教学中普遍存在的具体问题,对郑州大学体育课程教学体系进行改革尝试与实践.经过四年的不断探索、研究与实验,逐渐形成了我校体育课程教学模式:体育办学思路与教学观念是“以人为本,健康第一,终身体育,素质教育”;按照“一年级普修课;二年级专项课;三年级以上学生‘三自主’选修课;身体特殊学生开设康复保健课”的体育课程设置的原则,开设体育课程;利用体育课堂教学、课余群体活动的参与和浓厚的校园内外体育文化氛围,面向全体在校学生开展体育课程改革与实验,保证学生每天锻炼一小时.达到全面培养学生体育意识、体育能力、体育习惯和体育文化素养,能够健康工作五十年、幸福生活一辈子的大学体育课程培养之目标.