Pair‐copula constructions for non‐Gaussian DAG models

We propose a new type of multivariate statistical model that permits non‐Gaussian distributions as well as the inclusion of conditional independence assumptions specified by a directed acyclic graph. These models feature a specific factorisation of the likelihood that is based on pair‐copula constructions and hence involves only univariate distributions and bivariate copulas, of which some may be conditional. We demonstrate maximum‐likelihood estimation of the parameters of such models and compare them to various competing models from the literature. A simulation study investigates the effects of model misspecification and highlights the need for non‐Gaussian conditional independence models. The proposed methods are finally applied to modeling financial return data. The Canadian Journal of Statistics 40: 86–109; 2012 © 2012 Statistical Society of Canada     

Approximate jackknife empirical likelihood method for estimating equations

It is known that the profile empirical likelihood method based on estimating equations is computationally intensive when the number of nuisance parameters is large. Recently, Li, Peng, & Qi (2011) proposed a jackknife empirical likelihood method for constructing confidence regions for the parameters of interest by estimating the nuisance parameters separately. However, when the estimators for the nuisance parameters have no explicit formula, the computation of the jackknife empirical likelihood method is still intensive. In this paper, an approximate jackknife empirical likelihood method is proposed to reduce the computation in the jackknife empirical likelihood method when the nuisance parameters cannot be estimated explicitly. A simulation study confirms the advantage of the new method. The Canadian Journal of Statistics 40: 110–123; 2012 © 2012 Statistical Society of Canada     

Restricted maximum likelihood estimation of joint mean‐covariance models

The class of joint mean‐covariance models uses the modified Cholesky decomposition of the within subject covariance matrix in order to arrive to an unconstrained, statistically meaningful reparameterisation. The new parameterisation of the covariance matrix has two sets of parameters that separately describe the variances and correlations. Thus, with the mean or regression parameters, these models have three sets of distinct parameters. In order to alleviate the problem of inefficient estimation and downward bias in the variance estimates, inherent in the maximum likelihood estimation procedure, the usual REML estimation procedure adjusts for the degrees of freedom lost due to the estimation of the mean parameters. Because of the parameterisation of the joint mean covariance models, it is possible to adapt the usual REML procedure in order to estimate the variance (correlation) parameters by taking into account the degrees of freedom lost by the estimation of both the mean and correlation (variance) parameters. To this end, here we propose adjustments to the estimation procedures based on the modified and adjusted profile likelihoods. The methods are illustrated by an application to a real data set and simulation studies. The Canadian Journal of Statistics 40: 225–242; 2012 © 2012 Statistical Society of Canada     

A generalized Fleming and Harrington's class of tests for interval‐censored data

The class $G^{\rho,\lambda }$ of weighted log‐rank tests proposed by Fleming & Harrington [Fleming & Harrington (1991) Counting Processes and Survival Analysis, Wiley, New York] has been widely used in survival analysis and is nowadays, unquestionably, the established method to compare, nonparametrically, k different survival functions based on right‐censored survival data. This paper extends the $G^{\rho,\lambda }$ class to interval‐censored data. First we introduce a new general class of rank based tests, then we show the analogy to the above proposal of Fleming & Harrington. The asymptotic behaviour of the proposed tests is derived using an observed Fisher information approach and a permutation approach. Aiming to make this family of tests interpretable and useful for practitioners, we explain how to interpret different choices of weights and we apply it to data from a cohort of intravenous drug users at risk for HIV infection. The Canadian Journal of Statistics 40: 501–516; 2012 © 2012 Statistical Society of Canada     

阳光体育运动下中职体育课模块教学实证研究——以广西玉林农业学校为例

中职学校体育课采用“模块教学”是由学生根据自己的兴趣来选学某个体育项目,从而提高学生学习的主动性,吸引广大青少年学生走向操场,走到阳光下,积极主动参与体育锻炼,培养运动爱好和专长,树立终身体育的意识,实现国家“阳光体育”号召.采用文献资料法、专家访谈法和数理统计法对广西玉林农业学校体育模块教学现状进行了分析与研究,对当前体育模块教学实施中,在教学目标、课程内容设置、教师专项结构、教学物质保障以及教学考核评价等方面存在的问题提出了合理的建议和对策,以期使中职体育模块教学更加完善.     

Who is bullying whom in ethnically diverse primary schools? Exploring links between bullying,ethnicity, and ethnic diversity in Dutch primary schools

This study investigated associations between ethnicity, ethnic diversity, and bullying among 739 pupils enrolled in their last year of primary school. Hypotheses derived from social misfit and inter-ethnic relations theories were tested using the multilevel p₂ model. Our key findings were: (1) inter- and intra-ethnic bullying are just as common in ethnically heterogeneous as in homogeneous classes; (2) pupils belonging to the Turkish and Moroccan minority groups bully significantly more than native Dutch (in particular according to victims); the chance to be victimized does not depend on the ethnic background of the pupil; (3) the prevalence of inter- and intra-ethnic bullying depends on the level of ethnic diversity in the class; inter-ethnic and intra-ethnic bullying increase with increasing levels of ethnic diversity.     

论学校场域的本质、特点与功能

学校并不是一个静态的结构,它是由各种关系网络构成的一个"场域"。学校场域是指在学校教育中,由教师、学生以及其他相关人员围绕着知识的生产和传递,所形成的一种关系网络。学校场域具有整体性、自主性、中介性以及开放性等特点,具有认识导向、行为规范、榜样示范以及感染功能。     

谈梁晓声知青小说中的反思性问题

梁晓声知青小说以浓重的知青情结和对理想主义、英雄主义的高扬而独树一帜,在20世纪80年代的知青小说创作领域占据了重要的一席之地,不过,其知青小说因此而招来了不少的批评和质疑的声音,被认为小说中缺乏对知青运动、文革历史的深刻反思与批判。然而,纵观梁晓声的知青小说创作的流变,不难发现其小说创作的深层动因远不是一些论者所批评的那样简单,而是梁晓声的知青情结与创作伦理的背后更为主要的原因,在于为一代知青的青春和生命找寻意义与价值的明证。     

中小学校长远程培训指导与管理策略研究——基于重庆文理学院中小学校长远程培训的案例

重庆市举办大规模中小学校长远程培训已于2010年拉开序幕.作为新型培训方式,远程培训逐步暴露出一些问题.本文结合远程培训的实践,在分析重庆市中小学校长远程培训存在问题的基础上,提出提高远程培训有效性的策略,以促进培训工作的发展.     

求职节目话语中的话目结构及语用策略——基于《非你莫属》的IRF分析

近两年来,越来越多的电视求职类节目亮相我国电视荧屏,形成一种新兴的语言现象。作为国内第一档职场真人秀栏目,《非你莫属》自开播以来便受到广大观众的关注和喜爱。本文从2013年的9期节目中选取了30段对话,先用伯明翰学派的话语分析方法解析出了该类会话的话目类别,然后挖掘出其中隐藏的话语权力不平等现象,最后提出相应的语用策略。希望本文的分析对求职者有效应对面试具有一定的指导意义。