一种简单有效的Q矩阵估计方法开发：基于非参数化方法视角

摘要：Q矩阵是认知诊断的基础,错误的Q矩阵会影响参数估计和被试诊断正确率,开发一种简单而有效的Q矩阵估计方法有助于Q矩阵的正确界定。相对于参数化的Q矩阵估计方法,本研究将海明距离（Hamming Distance,HD）用于Q矩阵估计,开发出一种简单有效的非参数化的Q矩阵估计方法。采用Monte Carlo模拟方法与实证研究相结合的研究范式,对该方法的科学性与合理性及其效果进行研究,研究结果发现（1）基于海明距离的Q矩阵估计法具有较高的估计正确率,并且该方法不受被试样本容量影响。（2）该方法简单易懂,运算时间短,是一种简单而有效的Q矩阵估计方法。（3）新方法对于Tatsuka（1990）分数减法测验的Q矩阵的估计准确率尚可,说明新方法在实践中具有较好的潜在应用前景与应用价值。     

Two efficient selection methods for high-dimensional CD-CAT utilizing max-marginals factor from MAP query and ensemble learning approach

Computerized adaptive testing for cognitive diagnosis (CD-CAT) needs to be efficient and responsive in real time to meet practical applications' requirements. For high-dimensional data, the number of categories to be recognized in a test grows exponentially as the number of attributes increases, which can easily cause system reaction time to be too long such that it adversely affects the examinees and thus seriously impacts the measurement efficiency. More importantly, the long-time CPU operations and memory usage of item selection in CD-CAT due to intensive computation are impractical and cannot wholly meet practice needs. This paper proposed two new efficient selection strategies (HIA and CEL) for high-dimensional CD-CAT to address this issue by incorporating the max-marginals from the maximum a posteriori query and integrating the ensemble learning approach into the previous efficient selection methods, respectively. The performance of the proposed selection method was compared with the conventional selection method using simulated and real item pools. The results showed that the proposed methods could significantly improve the measurement efficiency with about 1/2–1/200 of the conventional methods' computation time while retaining similar measurement accuracy. With increasing number of attributes and size of the item pool, the computation time advantage of the proposed methods becomes more significant.     

超越启蒙心态

启蒙心态(the enlightenment mentality)作为人类历史上最具活力和转化力的意识形态,是现代西方崛起的基础。实际上,作为现代特征的,人们关注的所有主要领域,比如科学技术、工业资本、市场经济、民主政治等等,都从启蒙心态中受惠或汲取养分。而且,我们追求的那些被视为属于现代意识的价值,比如自由、平等和人权等等,如果不是在结构上,就是在起源上,与启蒙心态密不可分。     

The Content of the Threat Matters: the Differential Effects of Quantitative and Qualitative Job Insecurity on Different Types of Employee Motivation

Given the conceptual differences between different types of job insecurity, it is important to distinguish qualitative job insecurity from quantitative job insecurity when examining their motivational consequences. Building on the approach and avoidance framework, we expect that quantitative job insecurity influences avoid-performance goal orientation (avoidance form of motivation) via psychological safety, whereas qualitative job insecurity influences learning goal orientation (approach form of motivation) via psychological meaningfulness. We also examine the moderating role of organizational justice in such effects. Using two-wave data collected from 281 employees in China, we found that quantitative job insecurity had a positive indirect effect on employee avoid-performance goal orientation via decreased psychological safety, whereas qualitative job insecurity had a negative indirect effect on employee learning goal orientation via decreased psychological meaningfulness. In addition, organizational justice buffered the direct effect of quantitative job insecurity on employee psychological safety and the subsequent indirect effect on employee avoid-performance goal orientation. However, organizational justice did not moderate the influence of qualitative job insecurity on employee outcomes. Our findings provide new insights into the motivational implications of job insecurity.

     

Measuring Associations of the Department of Veterans Affairs' Suicide Prevention Campaign on the Use of Crisis Support Services

Campaigns have become popular in public health approaches to suicide prevention; however, limited empirical investigation of their impact on behavior has been conducted. To address this gap, utilization patterns of crisis support services associated with the Department of Veterans Affairs' Veterans Crisis Line (VCL) suicide prevention campaign were examined. Daily call data for the National Suicide Prevention Lifeline, VCL, and 1‐800‐SUICIDE were modeled using a novel semi‐varying coefficient method. Analyses reveal significant increases in call volume to both targeted and broad resources during the campaign. Findings underscore the need for further research to refine measurement of the effects of these suicide prevention efforts.     

Comparative effectiveness of CBT interventions for co-morbid chronic pain & insomnia: A pilot study

IntroductionChronic pain is difficult to treat and often precedes or exacerbates sleep disturbances such as insomnia. Insomnia, in turn, can amplify the pain experience. Both conditions are associated with inflammatory processes, which may be involved in the bi-directional relationship between pain and sleep. Cognitive behavioral therapy (CBT) for pain and CBT for insomnia are evidence based interventions for, respectively, chronic pain and insomnia. The study objectives were to determine the feasibility of combining CBT for pain and for insomnia and to assess the effects of the combined intervention and the stand alone interventions on pain, sleep, and mood outcomes compared to a control condition.MethodsTwenty-one adults with co-occurring chronic pain and chronic insomnia were randomized to either CBT for pain, CBT for insomnia, combined CBT for pain and insomnia, or a wait-list control condition.ResultsThe combined CBT intervention was feasible to deliver and produced significant improvements in sleep, disability from pain, depression and fatigue compared to the control condition. Overall, the combined intervention appeared to have a strong advantage over CBT for pain on most outcomes, modest advantage over both CBT for insomnia in reducing insomnia severity in chronic pain patients.DiscussionCBT for pain and CBT for insomnia may be combined with good results for patients with co-occurring chronic pain and insomnia.     

Socially Anxious and Peer-Victimized Preadolescents: “Doubly Primed” for Distress?

We examined independent and interactive associations linking preadolescents' socially anxious feelings and peer victimization experiences with their social behaviors (rated by parents and teachers) and psychophysiological arousal during lab simulations of salient peer stress situations in preadolescence (peer evaluation and peer rebuff). Sixty-three preadolescents and one parent per preadolescent participated. Respiratory sinus arrhythmia (RSA), skin conductance level (SCL), and heart rate (HR) were assessed during peer stress situations. Preadolescents provided reports of social anxiety; preadolescents and parents reported on peer victimization; and parents and teachers rated prosocial and aggressive behaviors. Peer victimization moderated associations between social anxiety and both physiological arousal and social-behavior problems. As hypothesized, social anxiety was more strongly associated with lower RSA, higher HR, and higher aggressive behavior among preadolescents who experienced higher levels of peer victimization, compared to preadolescents who experienced lower levels of peer victimization.     

A Class of Distribution-Free Models for Longitudinal Mediation Analysis

Mediation analysis constitutes an important part of treatment study to identify the mechanisms by which an intervention achieves its effect. Structural equation model (SEM) is a popular framework for modeling such causal relationship. However, current methods impose various restrictions on the study designs and data distributions, limiting the utility of the information they provide in real study applications. In particular, in longitudinal studies missing data is commonly addressed under the assumption of missing at random (MAR), where current methods are unable to handle such missing data if parametric assumptions are violated. In this paper, we propose a new, robust approach to address the limitations of current SEM within the context of longitudinal mediation analysis by utilizing a class of functional response models (FRM). Being distribution-free, the FRM-based approach does not impose any parametric assumption on data distributions. In addition, by extending the inverse probability weighted (IPW) estimates to the current context, the FRM-based SEM provides valid inference for longitudinal mediation analysis under the two most popular missing data mechanisms; missing completely at random (MCAR) and missing at random (MAR). We illustrate the approach with both real and simulated data.     

临床思维与决策能力是医学教育的重要组成部分

临床思维与决策能力培养是医学生不可或缺的一门必修课程,临床医生实际上每天处于临床决策之中,必须为疾病提供诊断和治疗的决策.而当前临床医学生在此方面训练甚少,临床工作具有很大的不可预知性和不可确定性,尤其是在手术室繁忙、变化的环境中,进行高效的临床决策就显得尤其重要.本文阐述了临床思维与临床决策在医学教育中的重要地位及其相互关系,分析当前医学生临床实践中的思维与决策方面存在的问题.并从临床实际角度出发,探讨如何提高医学生临床思维与决策能力的方法,对促进医学教育模式改革,提高医学教育质量具有重要推动作用.