Latent variable selection in multidimensional item response theory models using the expectation model selection algorithm

The aim of latent variable selection in multidimensional item response theory (MIRT) models is to identify latent traits probed by test items of a multidimensional test. In this paper the expectation model selection (EMS) algorithm proposed by Jiang et al. (2015) is applied to minimize the Bayesian information criterion (BIC) for latent variable selection in MIRT models with a known number of latent traits. Under mild assumptions, we prove the numerical convergence of the EMS algorithm for model selection by minimizing the BIC of observed data in the presence of missing data. For the identification of MIRT models, we assume that the variances of all latent traits are unity and each latent trait has an item that is only related to it. Under this identifiability assumption, the convergence of the EMS algorithm for latent variable selection in the multidimensional two-parameter logistic (M2PL) models can be verified. We give an efficient implementation of the EMS for the M2PL models. Simulation studies show that the EMS outperforms the EM-based L₁ regularization in terms of correctly selected latent variables and computation time. The EMS algorithm is applied to a real data set related to the Eysenck Personality Questionnaire.     

“增益”还是“损耗”?挑战性工作要求对工作-家庭增益的“双刃剑”影响

基于资源保存理论和不确定管理理论, 采用日记研究法收集81个样本10个工作日的数据, 从静态和动态两个视角, 通过明晰挑战性工作要求的不同属性(每日水平、平均水平、日间变动、波动变化), 全面检验了挑战性工作要求对工作-家庭增益的影响。研究结果表明：(1)在静态模型中, 挑战性工作要求通过工作专注度(增益路径)和放松(损耗路径)作用于工作-家庭增益, 且在个体间的平均水平模型中, 放松的中介作用更为显著; (2)在动态模型中, 挑战性工作要求的日间变动和波动变化, 均通过减少员工工作专注度和放松, 进而降低工作-家庭增益。最后, 本研究讨论了管理者应重视挑战性工作要求的双刃剑作用等实践启示。     

角色压力、工作家庭冲突和心理抑郁的中美比较--社会支持的调节作用

在中国和北美两个样本中,探讨了工作家庭冲突模型的共性和差异。首先使用多组验证性因子分析找到适用于中美样本的模型,然后采用结构方程模型和多层次回归进行假设检验。结果显示,中美员工感知到的工作-家庭(家庭-工作)冲突在工作(家庭)角色压力和心理抑郁的关系中都起中介作用。此外,情境的差异导致中美员工在工作支持和家庭支持的调节作用上有不同的表现,即中国员工感受到的工作(家庭)支持对角色压力和冲突间关系的调节作用不显著,在北美样本中,工作支持负向调节工作角色压力到工作-家庭冲突的关系,而工作支持和家庭支持正向调节家庭角色压力到家庭-工作冲突的关系。本文的发现能够帮助管理者意识到情境因素的重要作用,从而制定更为有效的管理决策。     

On Pretabular Logics in NExtK4 (Part I)

This paper partly answers the question “what a frame may be exactly like when it characterizes a pretabular logic in NExtK4”. We prove the pretabularity crieria for the logics of finite depth in NExtK4. In order to find out the criteria, we create two useful concepts—“pointwise reduction” and “invariance under pointwise reductions”, which will remain important in dealing with the case of infinite depth.     

Effects of Image Preprocessing on Face Matching and Recognition in Human Observers

In person identification, recognition failure due to variations of illumination is common. In this study, we employed image‐processing techniques to tackle this problem. Participants performed recognition and matching tasks where the face stimuli were either original images or computer‐processed images in which shading was weakened via a number of image‐processing techniques. The results show that whereas recognition accuracy in a memory task was unaffected, some of the techniques significantly improved the identification performance in a face‐matching task. We conclude that relative to long‐term face memory, face matching is more susceptible to discrepancy of shading in different images of a face. Reducing the discrepancy by certain preprocessing techniques can facilitate person identification when original face images contain large illumination differences. Copyright © 2013 John Wiley & Sons, Ltd.     

Chronic administration of troxerutin protects mouse brain against d-galactose-induced impairment of cholinergic system

Previous evidence showed that administration of d-galactose (d-gal) increased ROS production and resulted in impairment of cholinergic system. Troxerutin, a natural bioflavonoid, has been reported to have many benefits and medicinal properties. In this study, we evaluated the protective effect of troxerutin against d-gal-induced impairment of cholinergic system, and explored the potential mechanism of its action. Our results displayed that troxerutin administration significantly improved behavioral performance of d-gal-treated mice in step-through test and morris water maze task. One of the potential mechanisms of this action was decreased AGEs, ROS and protein carbonyl levels in the basal forebrain, hippocampus and front cortex of d-gal-treated mice. Furthermore, our results also showed that troxerutin significantly inhibited cholinesterase (AchE) activity, increased the expression of nicotinic acetylcholine receptor alpha 7 (nAchRα7) and enhanced interactions between nAchRα7 and either postsynaptic density protein 95 (PSD95) or N-methyl-d-aspartate receptors subunit 1 (NMDAR1) in the basal forebrain, hippocampus and front cortex of d-gal-treated mice, which could help restore impairment of brain function.     

胰岛再生治疗的前景

胰岛β细胞数量减少和功能障碍是糖尿病的根本原因,现有的治疗手段主要以维持正常血糖水平为主要目的,尚无有效恢复受损胰岛功能的治愈性治疗手段.胰岛再生治疗将是一种可以恢复受损胰岛功能、改变糖尿病自然病程的崭新治疗手段.目前现有的噻唑烷二酮、肠促胰岛素及类似物、二肽基肽酶-4抑制剂等治疗,虽然不是一类新的胰岛再生药物,但其具有一定的促进胰岛再生、改善胰岛功能的作用.体外诱导β细胞再生也将为胰岛移植提供新的来源,为治愈糖尿病带来曙光.     

直觉对内隐学习优势效应的特异性贡献

已有人工语法的内隐学习研究中一个关键的问题是被试在不同指导语诱发下究竟形成了什么样的知识表征？实验借助结构知识的测量方式, 采用记忆和规则探索两种指导语, 考察了两组被试所获得的深层知识表征(结构知识)。结果发现：(1)在记忆指导语条件下, 被试获得了语法规则; (2)直觉在记忆指导语条件下贡献突出, 表现出特异性。该结果表明记忆指导语引发了被试基于直觉区分人工语法规则的内隐学习优势效应。     

推理能力、认知方式和启发量对顿悟问题解决不同阶段的影响*

从《科学发明创造实验问题材料库》中选取实验材料,采用“学习多个原型-测试多个问题”的两阶段实验范式,探究推理能力、认知方式和启发量对顿悟问题解决中原型激活与关键启发信息提取这两个阶段的影响。结果发现:(1)高推理能力被试比低推理能力被试的顿悟问题解决水平更高,且高推理能力被试在原型激活和关键启发信息提取上都显著优于低推理能力被试;(2)认知方式对原型激活和关键启发信息提取均没有影响;(3)启发量对原型激活没有影响,但对关键启发信息的提取有影响,并且高启发量的原型比低启发量的原型更能促进关键启发信息的提取。     

迫选式人格测验的传统计分与IRT计分模型

迫选测验的传统计分方式会产生自模式数据, 不能进行传统的信效度检验、因素分析和方差分析等。近年来研究者提出了一些基于项目反应理论的计分模型, 如瑟斯顿IRT模型和MUPP模型等, 它们可以规避自模式数据的弊端。瑟斯顿IRT模型方便进行参数估计, 模型定义灵活; 而MUPP模型的拓展性较差, 参数估计的方法有待提高。另一方面, 已有研究者基于MUPP模型开发了一些抗作假的迫选测验, 而瑟斯顿IRT模型距离这种应用还比较远。此外, 两个模型的适用性和有效性都有待更多的实证研究来检验。