Discovery algorithms for hierarchical relations

Two algorithms based on a latent class model are presented for discovering hierarchical relations that exist among a set ofK dichotomous items. The two algorithms, stepwise forward selection and backward elimination, incorporate statistical criteria for selecting (or deleting) 0–1 response pattern vectors to form the subset of the total possible 2 ^k vectors that uniquely describe the hierarchy. The performances of the algorithms are compared, using computer-constructed data, with those of three competing deterministic approaches based on ordering theory and the calculation of Phi/Phi-max coefficients. The discovery algorithms are also demonstrated on real data sets investigated in the literature.     

Post-Traumatic Reactions in Adolescents: How Well Do the DSM-IV PTSD Criteria Fit the Real Life Experience of Trauma Exposed Youth?

This study examined the structure and symptom specific patterns of post traumatic distress in a sample of 1,581 adolescents who reported exposure to at least one traumatic event. Symptom reporting patterns are consistent with past literature in that females reported more symptoms than males and older youth reported more symptoms than did their younger peers. Young people reporting exposure to exclusively violent type traumas were also found to be more likely to endorse symptoms than peers exposed exclusively to non violent type traumas. Confirmatory factor analysis provided stronger support for a four-factor model of PTSD than either the DSM-IV model or an alternate model. Further examination of the four factor model revealed gender differences in factor loadings with small to moderate effect sizes for recurrent, distressing memories, flashbacks, restricted affect, difficulty remember details, detachment, limited future orientation, hypervigilance and startle symptoms. Differences in factor loadings with the four factor model were also noted between younger and older adolescents, with medium to large effect sizes on the arousal items. In contract, comparison of the factor loadings revealed only small differences between youth exposed exclusively to violent traumatic stressors and those exposed exclusively to non violent traumatic stressors, suggesting relative similarity between these two groups.     

腹腔镜手术治疗子宫内膜异位症的临床价值

子宫内膜异位症是妇科常见病、多发病之一,可引起痛经、慢性盆腔痛、性交痛和不孕等症状,严重影响育龄期妇女的身心健康和生活质量,日益受到人们的关注。以人为本,微创手术是当代医学的模式之一。本文从哲学的角度出发、以辩证的观点对腹腔镜手术治疗子宫内膜异位症的临床价值进行综述。     

Power of the likelihood ratio test in covariance structure analysis

A procedure for computing the power of the likelihood ratio test used in the context of covariance structure analysis is derived. The procedure uses statistics associated with the standard output of the computer programs commonly used and assumes that a specific alternative value of the parameter vector is specified. Using the noncentral Chi-square distribution, the power of the test is approximated by the asymptotic one for a sequence of local alternatives. The procedure is illustrated by an example. A Monte Carlo experiment also shows how good the approximation is for a specific case.This research was made possible by a grant from the Dutch Organization for Advancement of Pure Research (ZWO). The authors also like to acknowledge the helpful comments and suggestions from the editor and anonymous reviewers.     

Positive and negative associations underlying ambivalent attitudes

In two studies, we compared the strength of positive and negative associations of ambivalent attitudes to those of nonambivalent attitudes. In Study 1, results from an implicit association task showed that, in contrast to nonambivalent attitudes, ambivalent attitudes were characterized by strong positive and negative associations. In Study 2 responses to ambivalent attitude objects were faster following a positive as well as following a negative prime, compared to a non-word prime, whereas for neutral attitude objects prime type did not influence response times. Results provide direct evidence for the assumption that both positive and negative associations of ambivalent attitudes are relatively strong. Implications for attitude strength and attitude structure are discussed.     

初中生师生关系的结构与类型研究

该文采用深度访谈、理论分析等方法编制初中生师生关系评定问卷,经探索性因素分析、验证性因素分析得出初中生师生关系包括理解性、回避性、亲密性、反应性及冲突性五个因素.研究编制的初中生师生关系评定问卷具有较好的信度和效度.聚类分析结果表明,初中生师生关系包括矛盾困顿型、冲突回避型、亲密和谐型及平淡顺应型等四种类型.     

Measuring Meaning in Life

The present studies addressed the need for a comprehensive, economical, and psychometrically adequate measure of existential meaning. In Study 1, principal-axis factor analysis of participants’ responses to popular meaning measures identified five latent constructs underlying them, labelled purposeful life, principled life, valued life, exciting life, and accomplished life. These dimensions resonate with the meaning in life concept as understood by Frankl (1963. Man’s search for meaning. (Revised Ed.) London: Hodder & Stoughton) and the panoply of subsequent theoretical definitions (e.g. Battista and Almond. (1973). Psychiatry, 36, 409–427; 2000. Exploring existential meaning: Optimising human development across the life span (pp. 39–55). USA: Sage; 1998. The human quest for meaning: A handbook of psychological research and clinical applications (pp. 11–140). Mahwah: Lawrence Erlbaum). Study 2 used these results as a foundation for developing a psychometrically satisfactory self-report questionnaire of each of these aspects of meaning in life. Confirmatory factor analysis (CFA) validated a five-factor structure, with each factor loading on a common second-order factor. Study 3 provided evidence for this new measure’s convergent validity and economic property. The final Meaningful Life Measure is reported and provides comprehensive but differentiated measurement of the meaning in life construct.     

Maximization of sums of quotients of quadratic forms and some generalizations

Monotonically convergent algorithms are described for maximizing six (constrained) functions of vectors x, or matricesX with columns x₁, ..., x _r . These functions are h₁(x)= _k (xA _kx)(xC _kx)^–1, H₁(X)= _k tr (XA _k X)(XC _k X)^–1, h₁(X)= _{k l} (x _l A _kx _l ) (x _l C _kx _l )^–1 withX constrained to be columnwise orthonormal, h₂(x)= _k (xA _kx)²(xC _kx)^–1 subject to xx=1, H₂(X)= _k tr(XA _kX)(XA_kX)(XC_kX)^–1 subject toXX=I, and h₂(X)= _{k l} (x _l A _kx _l )² (x _l C _kX _l )^–1 subject toXX=I. In these functions the matricesC _k are assumed to be positive definite. The matricesA _k can be arbitrary square matrices. The general formulation of the functions and the algorithms allows for application of the algorithms in various problems that arise in multivariate analysis. Several applications of the general algorithms are given. Specifically, algorithms are given for reciprocal principal components analysis, binormamin rotation, generalized discriminant analysis, variants of generalized principal components analysis, simple structure rotation for one of the latter variants, and set component analysis. For most of these methods the algorithms appear to be new, for the others the existing algorithms turn out to be special cases of the newly derived general algorithms.This research has been made possible by a fellowship from the Royal Netherlands Academy of Arts and Sciences to the author. The author is obliged to Jos ten Berge for stimulating this research and for helpful comments on an earlier version of this paper.     

教师解决结构不良问题策略的发展研究

以成人期个体解决结构不良问题的有关认知加工理论为框架,运用多因素设计的方法,对９０名不同年龄的教师在解决教育和教学实践中常见的三种冲突情景下使用策略的情况进行了探讨。结果发现,教师在解决结构不良问题时,从总体上说不存在年龄差异,但在处理教师与教师、教师与家长等较为复杂的冲突问题时,随着年龄的增长,更趋向于使用元认知和认识论认知策略。该研究对教师培训中如何根据不同年龄特点来进行教育机智训练有一定的理论意义和应用价值。