神经干细胞体外诱导分化的研究进展

神经干细胞是近年来脑科学研究的热点,其自我更新和多向分化的潜能为中枢神经系统疾病的治疗提供了可能,但如何使神经干细胞向特定的方向分化却一直是研究的难点。本文对神经干细胞体外的诱导分化因素及分化过程中的相关蛋白质组的研究做一综述。     

利用伪随机信号系统辨识钻柱系统

用白噪声信号作为输入信号对钻柱系统脉冲响应进行辨识。研究了伪随机信号的特征及伪随机信号产生的方法,得出了用伪随机信号代替白噪声信号辨识钻柱系统脉冲响应的结论。结合输入信号和输出信号,利用钻柱系统的脉冲响应,讨论了钻柱的临界转速、钻柱共振、钻柱与井壁之间的相互作用、所钻地层岩性等钻井工程问题。     

基于SAO语义分析的潜在技术合作伙伴识别

将SAO语义结构信息引入技术伙伴识别选择过程中，构建基于SAO语义分析的技术合作伙伴识别体系，通过对企业进行技术愿景分析、企业知识库分析确定技术合作网络，对网络内企业重点子技术领域进行相似度分析，从而识别企业潜在的技术合作伙伴，并制定针对性的合作方案。以染敏太阳能电池为案例开展实证研究，验证了该方法体系的可行性。     

使用词汇化句干对二语语用能力的影响

大多数语言中均普遍存在相当数量的词汇化句干，此类语言信息块的使用能够缩短使用者话语输出的编码时间，提高理解语言输入的解码效率。故此，二语学习者需要增强对目标语语块信息的注意力，将之内化进而提高二语语用能力。词汇化句干对中介语发展的实证研究表明，词汇化句干的使用将促进中介语的发展。     

Sequential confidence intervals for the number of cells in a multinomial population

A two-sided sequential confidence interval is suggested for the number of equally probable cells in a given multinomial population with prescribed width and confidence coefficient. We establish large-sample properties of the fixed-width confidence interval procedure using a normal approximation, and some comparisons are made. In addition, a simulation study is carried out in order to investigate the finite sample behaviour of the suggested sequential interval estimation procedure.     

Terrorist Population Dynamics Model

A system that includes a number of terrorist cells is considered. The cells can consist of one or more terrorists. The current number of terrorist cells is further denoted by N(t), where t is a current time counted from any appropriate origin. The objective is to find the evolution of the system in terms of N(t) and some interpretable parameters, such as the initial number of the terrorist cells N0=N(0), the cell disabling rate constant lambda (or the cell half-life t1/2), and the rate of formation of new cells P. The cost-effectiveness analysis, performed in the framework of the model, reveals that the effectiveness of disabling a terrorist cell is getting worse after 2-3 half-lives of a cell, which shows that if the anti-terrorist actions have not reached their goal during that time, the respective policy should be considered for revision, using the risk assessment consideration. Another important issue raised concerns balancing the efforts related to counterterrorism actions inside the system and the efforts protecting its borders. The respective data analysis is suggested and illustrated using simulated data.     

A note on connectedness in fixed effects manova and gmanova models withmissing cells

Murray and Smith (1985) and Hocking (1985) give a generalized definition and test of connectedness in the case of missing cells using the univariate cell-means model with linear restrictions on the cell-means. The test of connectedness is here extended to multivariate fixed effects models, including the usual MANOVA model with linear restrictions, the MANOVA model with double linear restrictions, and the GMANOVA model.     

北欧各国配子捐赠制度及其对我国的启示

配子捐赠有助于不孕不育患者实现为人父母的美好愿望。而随之产生的一系列伦理法律问题仍有待探讨解决。匿名配子捐赠存废问题、卵子捐赠的可接受性问题和捐赠配子的补偿问题是北欧各国讨论中较突出的问题。北欧国家对这些问题做了大量研究,积累了丰富经验,并制定了法律法规。中国的配子银行建设仍在起步阶段,需要借鉴北欧经验,以便更好地满足配子捐赠的需要。     

Data Dependent Cells Chi‐Square Test With Recurrent Events

We consider a recurrent event wherein the inter‐event times are independent and identically distributed with a common absolutely continuous distribution function F. In this article, interest is in the problem of testing the null hypothesis that F belongs to some parametric family where the q‐dimensional parameter is unknown. We propose a general Chi‐squared test in which cell boundaries are data dependent. An estimator of the parameter obtained by minimizing a quadratic form resulting from a properly scaled vector of differences between Observed and Expected frequencies is used to construct the test. This estimator is known as the minimum chi‐square estimator. Large sample properties of the proposed test statistic are established using empirical processes tools. A simulation study is conducted to assess the performance of the test under parameter misspecification, and our procedures are applied to a fleet of Boeing 720 jet planes' air conditioning system failures.     

1973 Section Officers,Committees and Association Representatives

The occurrence of missing data cells precludes a universally correct procedure for performing an analysis of variance. This is illustrated by the use of two computer routines to analyze a 2 × 3 factorial experiment with one missing cell. One of these routines does, however, provide information that may enhance the usefulness of the associated results.