Two simple approximations to the distributions of quadratic forms

Many test statistics are asymptotically equivalent to quadratic forms of normal variables, which are further equivalent to with z_i being independent and following N(0,1). Two approximations to the distribution of T have been implemented in popular software and are widely used in evaluating various models. It is important to know how accurate these approximations are when compared to each other and to the exact distribution of T. The paper systematically studies the quality of the two approximations and examines the effect of the λ_i and the degrees of freedom d by analysis and Monte Carlo. The results imply that the adjusted distribution for T can be as good as knowing its exact distribution. When the coefficient of variation of the λ_i is small, the rescaled statistic is also adequate for practical model inference. But comparing T_R against will inflate type I errors when substantial differences exist among the λ_i, especially, when d is also large.     

Bayesian analysis of mixtures in structural equation models with non‐ignorable missing data

Structural equation models (SEMs) have become widely used to determine the interrelationships between latent and observed variables in social, psychological, and behavioural sciences. As heterogeneous data are very common in practical research in these fields, the analysis of mixture models has received a lot of attention in the literature. An important issue in the analysis of mixture SEMs is the presence of missing data, in particular of data missing with a non‐ignorable mechanism. However, only a limited amount of work has been done in analysing mixture SEMs with non‐ignorable missing data. The main objective of this paper is to develop a Bayesian approach for analysing mixture SEMs with an unknown number of components and non‐ignorable missing data. A simulation study shows that Bayesian estimates obtained by the proposed Markov chain Monte Carlo methods are accurate and the Bayes factor computed via a path sampling procedure is useful for identifying the correct number of components, selecting an appropriate missingness mechanism, and investigating various effects of latent variables in the mixture SEMs. A real data set on a study of job satisfaction is used to demonstrate the methodology.     

Determinants of Standard Errors of MLEs in Confirmatory Factor Analysis

This paper studies changes of standard errors (SE) of the normal-distribution-based maximum likelihood estimates (MLE) for confirmatory factor models as model parameters vary. Using logical analysis, simplified formulas and numerical verification, monotonic relationships between SEs and factor loadings as well as unique variances are found. Conditions under which monotonic relationships do not exist are also identified. Such functional relationships allow researchers to better understand the problem when significant factor loading estimates are expected but not obtained, and vice versa. What will affect the likelihood for Heywood cases (negative unique variance estimates) is also explicit through these relationships. Empirical findings in the literature are discussed using the obtained results.     

当前竞技体育伦理问题及其实质

竞技体育的伦理问题,不仅仅应该批判竞技体育中的非伦理现象,而且应该着重考察在竞技体育发展中自身衍生的目的和手段及发展方向的异化问题,这种伦理悖论才是实质的竞技体育伦理问题。解决问题的途径是竞技体育的自我调整和竞技体育伦理的建设。     

论墨家的道德精神

墨家也和儒家一样,具有非常明显的道德至上的思想倾向。他们倡导如下基本道德精神:反对不劳而获,提倡“为人犹为己”,强调义利统一、志功统一。     

战争伦理:一种世界观念

战争伦理主要论及战争如何受到道德强制,或者说,它涉及道德的进步如何影响到战争。同时,与人类其他活动相比,战争行为更具国际性,因此,战争伦理作为抑制战争的一种道义力量,也更易成为一种世界观念。可以将战争伦理分为军事伦理、军备伦理、军人伦理三个层面,分别代表基于人、武器以及人与武器相结合而采取的行动———作战之上的伦理规范,它们都是随着时代的发展而发展的。     

我国护理教育面临的困境及对策研究

梳理了目前国内外护理教育发展的基本情况,从满足我国护理事业发展需求、充分考虑现代护理学的学科特点、明确护理高等教育不同层次的培养目标等方面分析了护理教育发展的主要思路,并提出具体的建议和措施,力图通过加强护理学教育来进一步推动我国护理事业的发展。     

结果预期对青少年攻击性行为的影响：中介效应与调节效应

采用攻击性问卷、关系攻击行为量表、结果预期量表、移情量表和自我控制能力问卷对720名中学生进行调查,考察了结果预期与青少年攻击性行为的关系,以及自我控制在其中的中介作用和移情在其中的调节作用。结果发现:(1)结果预期与青少年的攻击性行为(外部攻击和关系攻击)存在显著负相关;(2)自我控制在结果预期与青少年攻击性行为之间起着完全中介作用;(3)在结果预期对青少年外部攻击行为的预测中,移情发挥了调节作用。在高移情个体中,结果预期并不预测外部攻击行为,而在低移情个体中,结果预期显著地反向预测外部攻击行为;(4)自我控制在结果预期与青少年外部攻击行为之间的中介作用受到移情的调节,高水平的移情能力可以有效地缓解青少年因低自我控制而导致的高攻击性。     

肿瘤临终关怀中的家属辞世教育

晚期癌症患者的家属在临终家居照顾及医院宁养照顾中起到重要的作用,对临终患者家属的关怀照顾是临终关怀的重要组成部分,通过从家属心理特点、影响家属心理的因素、家属辞世教育方法三个方面具体阐述在家属辞世教育的工作步骤,从而更好的指导社会医疗实践,促进临终关怀工作在我国的发展.     

防止耐药菌的院内爆发

临床上多重耐药菌感染的现象正在日渐严重,从而引发了越来越严重的耐药菌院内感染现象.从医务工作者角度来控制这一现象的有效措施包括:规范医护人员的手卫生,控制侵入性操作引起的感染,合理使用抗生素,有效筛查和隔离疑似感染患者等.