创业投资的治理作用：基于代理成本视角的实证分析

选取2004年至2012年中国沪、深两市首次公开发行上市的1 216家公司作为研究对象,采用相关分析、多元回归分析和工具变量等多种统计分析方法,从代理成本视角探讨创业投资对中国上市公司的治理作用。从总体上检验创业投资参与对中国上市公司代理成本的影响,进一步检验创业投资的参与程度和背景特征是否影响其治理作用的发挥。研究结果表明,有创业投资机构参与的上市公司,其代理成本显著低于无创业投资机构参与的上市公司;创业投资的参与程度越深,即创业投资机构家数越多、持股比例越高、投资期限越长,上市公司的代理成本就越低;与本土背景的创业投资机构相比,外资背景的创业投资机构更能降低上市公司的代理成本。研究结论对上市公司、创业投资机构和政策制定者具有重要借鉴意义和参考价值。     

Using the EM-algorithm for survival data with incomplete categorical covariates

Incomplete covariate data is a common occurrence in many studies in which the outcome is survival time. With generalized linear models, when the missing covariates are categorical, a useful technique for obtaining parameter estimates is the EM by the method of weights proposed in Ibrahim (1990). In this article, we extend the EM by the method of weights to survival outcomes whose distributions may not fall in the class of generalized linear models. This method requires the estimation of the parameters of the distribution of the covariates. We present a clinical trials example with five covariates, four of which have some missing values.     

History of sexual abuse and parental alcohol misuse: Risk,outcomes and protective factors in adolescents

This study examined the school performance, suicidal involvement, disordered eating behaviors, pregnancy risk and chemical use of teenagers with a history of sexual abuse or parental alcohol misuse and found that they had higher rates of these adverse outcomes than among a comparison group of teenagers without such background risk factors. Adolescents with dual-risk background reported higher levels of suicide risk, disordered eating, sexual behaviors and chemical abuse than teenagers with only one background risk factor. Among index group members, protective factors against these adverse outcomes included a high degree of religiosity and the ability to discuss problems with family or friends. Risk factors that increased the likelihood of adverse outcomes included depression, perceived substance use in school and worries about family financial security.The first author was supported in the preparation of this article by a grant from the Lois and Samuel Silberman Fund of New York.     

The Effect of Gender Context on Children's Social Behavior in a Limited Resource Situation: An Observational Study

Knowing when to compete and when to cooperate to maximize opportunities for equal access to activities and materials in groups is critical to children's social and cognitive development. The present study examined the individual (gender, social competence) and contextual factors (gender context) that may determine why some children are more successful than others. One hundred and fifty‐six children (M age=6.5 years) were divided into 39 groups of four and videotaped while engaged in a task that required them to cooperate in order to view cartoons. Children within all groups were unfamiliar to one another. Groups varied in gender composition (all girls, all boys, or mixed‐sex) and social competence (high vs. low). Group composition by gender interaction effects were found. Girls were most successful at gaining viewing time in same‐sex groups, and least successful in mixed‐sex groups. Conversely, boys were least successful in same‐sex groups and most successful in mixed‐sex groups. Similar results were also found at the group level of analysis; however, the way in which the resources were distributed differed as a function of group type. Same‐sex girl groups were inequitable but efficient whereas same‐sex boy groups were more equitable than mixed groups but inefficient compared to same‐sex girl groups. Social competence did not influence children's behavior. The findings from the present study highlight the effect of gender context on cooperation and competition and the relevance of adopting an unfamiliar peer paradigm when investigating children's social behavior.     

Do bootstrap confidence procedures behave well uniformly in P?

An important statistical problem is to construct a confidence set for some functional T(P) of some unknown probability distribution P. Typically, this involves approximating the sampling distribution J_n(P) of some pivot based on a sample of size n from P. A bootstrap procedure is to estimate J_n(P) by J_n(&Pcirc;_n), where P?_n is the empirical measure based on a sample of size n from P. Typically, one has that J_n(P) and J_n(P?_n) are close in an appropriate sense. Two questions are addressed in this note. Are J_n(P) and J_n(P?_n) uniformly close as P varies as well? If so, do confidence statements about T(P) possess a corresponding uniformity property? In the case T(P) = P, the answer to the first questions is yes; the answer to the second is no. However, bootstrap confidence statements about T(P) can be made uniform over a restricted, though large, class of P. Similar results apply to other functional T(P).     

中国大学战略绩效评价探析——基于平衡计分卡理论的研究

本文基于平衡计分卡的思路和方法，以大学的发展战略和办学使命为出发点，聚焦于人才培养和科技创新，以资源的获取与有效利用为平衡点，以战略执行能力提升为基点，构建了我国大学战略绩效评价体系，旨在有助于更新战略思维，有效提升大学战略执行能力、整体素质与竞争能力，     

浅谈大学英语优化教学

目前我们面临着教育体制由应试教育向素质教育转注的问题,因此大学英语优化教学颇为重要.本文就如何进行大学英语优化教学进行了探讨,并提出了一些具体做法.     

Canonical correlation analysis of residential and vocational outcomes following psychiatric rehabilitation

This analysis uses canonical correlation techniques to explore client outcomes following psychosocial rehabilitation services in two rehabilitation areas: vocational and residential. At issue are the ways in which these two outcomes are affected by a series of eight client characteristics and service delivery features. The overarching question is the effectiveness of the program in establishing independence vocationally and residentially, and whether the same set of factors influences these two outcomes for persons with mental illness. Subjects were 212 ex-clients of a psychosocial rehabilitation agency who were working six months after leaving the program. The analysis derived two canonical functions both of which were significant. Canonical loadings and cross loadings indicated that client level of functioning and program tenure loaded most strongly with residential status on the first canonical variate while education loaded most strongly with salary on the second. These results support the notions that different predictors account for the variance associated with different outcomes following psychosocial rehabilitation. Discussion of the relevance of strong predictor variables highlights ways they can impact program design. Finally, the usefulness of canonical correlation in longitudinal program evaluation research is explored.     

Bayesian phylogenetic inference from animal mitochondrial genome arrangements

Summary. The determination of evolutionary relationships is a fundamental problem in evolutionary biology. Genome arrangement data are potentially more informative than deoxyribonucleic acid sequence data for inferring evolutionary relationships between distantly related taxa. We describe a Bayesian framework for phylogenetic inference from mitochondrial genome arrangement data using Markov chain Monte Carlo methods. We apply the method to assess evolutionary relationships between eight animal phyla.