基于矩阵打分值和化学位移值预测酶蛋白质中β-发夹模体

酶是一类具有催化功能的蛋白质,对其结构和功能的研究是非常有必要的。特殊模体β-发夹是一种简单的超二级结构,它们包含了丰富的折叠信息,对酶中β-发夹的预测有助于酶结构和功能的预测。本文建立了非冗余的β-发夹模体数据集,包含1080条酶蛋白质链,2818个β-发夹模体,1098个非β-发夹。提取位点亲疏水组分及位点亲疏水紧邻关联组分作为参数,运用矩阵打分算法得到的预测结果不理想。将位点亲疏水、位点亲疏水紧邻关联组分为参数得到的打分值和平均化学位移值共同作为特征参数,输入支持向量机算法对模体进行预测,5交叉检验预测总精度是81.8%,相关系数达到了0.636。     

关于政府构建与完善中小企业支持体系的思考

中小企业的发展,在推进国有企业改革、解决下岗职工再就业、增加财政收入、搞活城乡经济和加快小城镇建设等方面发挥了不可替代的作用。在我国中小企业的发展中,长期存在着一些制约其快速发展的因素,迫切需要政府构建和完善中小企业支持体系,以推动中小企业的持续、健康发展。     

Disaster and Development Paradigms: Too Close for Comfort?

The familiar distinctions between the disaster and development paradigms have become increasingly blurred. Yet, conceptual and policy dilemmas continue to pose challenges for the integration of the two paradigms into a single framework. Drawing on the literature and Ethiopia's Institutional Support Project, this article argues that the increased convergence of the two constructs may be too close for comfort, thus rendering the assertion that disaster‐risk reduction can help achieve sustainable development and vice versa mere rhetoric. Unless there is a shift from focusing on the hazard event to also recognising that disasters are not politically neutral, there is a danger of being locked into the hazard paradigm, despite the different labels, titles or metaphors that may be assigned to it.     

日本《低碳投资促进法》述评

日本参议院于5月18日通过了《低碳投资促进法》,该法是日本建设低碳社会的最新立法,规定了对从事适合能源环境的制品开发与制造的特定事业者提供筹资支持,需求开拓支援法人承保租赁合同等措施,对我国的相关立法有一定的借鉴意义。     

Feature selection and machine learning with mass spectrometry data for distinguishing cancer and non-cancer samples

This is a comparative study of various clustering and classification algorithms as applied to differentiate cancer and non-cancer protein samples using mass spectrometry data. Our study demonstrates the usefulness of a feature selection step prior to applying a machine learning tool. A natural and common choice of a feature selection tool is the collection of marginal p-values obtained from t-tests for testing the intensity differences at each m/z ratio in the cancer versus non-cancer samples. We study the effect of selecting a cutoff in terms of the overall Type 1 error rate control on the performance of the clustering and classification algorithms using the significant features. For the classification problem, we also considered m/z selection using the importance measures computed by the Random Forest algorithm of Breiman. Using a data set of proteomic analysis of serum from ovarian cancer patients and serum from cancer-free individuals in the Food and Drug Administration and National Cancer Institute Clinical Proteomics Database, we undertake a comparative study of the net effect of the machine learning algorithm–feature selection tool–cutoff criteria combination on the performance as measured by an appropriate error rate measure.     

Bayesian Analysis of DSGE Models by S. An and F. Schorfheide

The paper that An and Schorfheide have written is an excellent piece of work and will become a useful reference for teaching and consultation purposes. The paper discusses in an articulate and convincing manner almost everything that one could think of covering in such a review. This makes the task of the commentator difficult. Nevertheless, I will attempt to add few insights on three issues which, in my opinion, play an important role in applied work and in the interpretation of the estimation result. In particular, I will discuss a) the sensitivity of posterior distributions to prior spreads; b) the effects of model misspecification and an approach to model respecification; c) parameter identification and its consequences for posterior inference.     

发展草业关键在于比较优势和政策拉动

把草业作为农业结构调整的一项重要产业来开发,关键是要看种草与种植农作物在单位面积上的比较优势如何,同时还须有政策的支持和引导,坚持科学规划,运用市场机制,激活生产要素流动,优化资源配置,创新管理机制,综合地开发利用,其结合点在于合理地配置土地资源,优化土地利用结构,实现土地自由流转,依法种草,强化法制管理,真正把草地建设、保护、管理工作搞上去.     

对确定三相变压器连接组标号的教学及实践

三相变压器连接组标号的确定在实际工作和教学过程中,经常遇到.有时参考方向不明确,也较繁,掌握和理解起来有困难,容易出错.本文根据几年的教学实践,从特殊到一般,由浅入深,对三相变压器连接组标号的确定进行了归纳、总结,得出规律.实践证明,效果较好.     

Child support guidelines: Economic theory and policy considerations

Federal legislation has mandated that all states develop numeric guidelines for child support awards in divorce and paternity suits. The purpose of this article is to review the theoretical models currently used in guidelines development and to present an analysis of issues pertinent to the development and use of guidelines. A familiarity with the principles underlying child support guidelines will assist family scientists who may be called upon to provide expertise on this public policy issue.Barbara R. Rowe is Family Resource Management Extension Specialist, College of Family Life, Utah State University, Logan, UT 84322-2949. Her research interests include the economics of divorce and at-home-income-generation. She received her Ph.D. from Oregon State University.     

The ubiquitous angle

Summary.  Previously we used the geometry of n -dimensional space to derive the paired samples t -test and its p -value. In the present paper we describe the 'ubiquitous' application of these results to single degree of freedom linear model hypothesis tests. As examples, we derive the p - and t -values for the independent samples t -test, for testing a contrast in an analysis of variance and for testing the slope in a simple linear regression analysis. An angle θ in n -dimensional space is again pivotal in the development of the ideas. The relationships between p , t , θ , F and the correlation coefficient are also described by using a 'statistical triangle'.