Understanding scale-dependent yield stress of metals at micrometre scales

The mechanical softening behaviour of micrometre-scale metals (free-standing metal foils and wires) with decreasing either the geometrical or the microstructural scale (i.e. the smaller, the weaker) has recently been reported. Here, we present a mechanism-based model to understand the softening behaviour, which is based on competition between the effects of surface grain relaxation and the interior grain strengthening effect. The model describes well the yield stress of Cu foils with different ratios of the thickness to grain size.     

Confidence in accuracy moderates the benefits of retrieval practice

ABSTRACT

The effect of Retrieval Practice refers to the phenomenon that taking a practice test is more effective for learning than re-study, probably due to the benefit from processes underlying successful retrievals during practice. However, it is rarely studied whether other processes (e.g., metacognitive monitoring) during retrieval practice may also play an important role. In two experiments, we examined whether the effectiveness of retrieval was affected by subjects’ confidence in their retrieval success. Subjects studied word-pairs and rated their confidence after each practice test trial (cued-recall in Exp.1, multiple choice in Exp.2), or re-study trial. In both experiments, we observed the classic retrieval practice effect. Moreover, in Exp.2, the benefits differed as a function of subjects’ confidence in their retrieval performance: the effect of retrieval practice only emerged for high-confidence trials with higher than 56% confidence. In summary, the retrieval practice only facilitates the retention of correct answers with high confidence.     

情绪作为道德判断的“催化剂”：道德判断中的评价倾向与特异性效应

在不同领域的道德判断中,情绪可能起着“催化剂”的作用。一种特定情绪对应一种核心评价;一种情绪只影响某一道德领域的判断,不同情绪的影响是特异性的;进化心理学和具身认知对道德判断中存在的评价倾向和特异性效应进行了解释。未来研究需要探索评价倾向与特异性效应的内在心理机制。以及进一步探讨文化等第三变量对不同情绪与特定领域道德判断的影响。     

一种多级评分的广义认知诊断模型

认知诊断是近些年教育测量研究中的热点,大多数的认知诊断模型仅适用于0～1评分的情况.本文提出一种有多个潜变量多个滑动参数的多级评分认知诊断模型——GP-D1NA,只要由评分标准和知识状态能确定理想反应模式,就可以利用此方法进行认知诊断分析.在该方法中,我们给出项目滑动矩阵的概念,将被试的观测得分均看成由某个理想得分的滑动,并采用EM算法估计滑动矩阵.在模拟研究中,采用每掌握一个属性得1分的评分标准,结果表明线性型、收敛型、发散型、无结构型和独立型五种属性层级结构均有较高的判准率.     

《心理统计学》教学内容的新探索

本文在对当前国内外主要心理统计学教材进行比较的基础上,指出与上个世纪八十年代的心理统计学教材内容相比较,在内容上的新探索主要体现在（1）由“假设检验”的内容中发展出“统计检验力”和“效果大小”的统计指标和估计方法;（2）引进一般线性模型来统合方差分析和回归分析这两种统计方法;（3）适度增加一些“多元统计分析”的内容等三个方面.本文对前两个方面的新内容作了简要评述,并对教材内容的编排方面提出了新的思路.     

主观幸福感测量研究

主观幸福感回溯式自陈报告测量存在一定的不足,在此基础上研究者们发展了关注时间因素的即时测量方法,如经验取样法(ESM),生态瞬时评定法(EMA),日重现法(DRM),U指数(The U-Index)等.从传统测量走向多样化测量大大提高了主观幸福感测量的生态效度,同时也为国民幸福指数的构建与评估提供了一定参考.     

心理资本在工作压力源和压力反应问的作用：调节还是中介？

谊研宛采用工作压力源量表、压力反应量表以及积极心理资本问卷对天津市某企业230名员工进行了调查。分析了心理资本与工作压力源和压力反应的关系及其作用机制。结果发现：（1）工作压力源对压力反应有显著的正向预洲作用;（2）心理资本对压力反应有显著的负向预测作用;（3）心理资本在工作压力源与压力反应之间起部分中介作用而不是调节作用,其中中介效应占总效应的比例为16％;（4）心理资本在各种工作压力源与压力反应问均起到中介作用,中介效应和直接效应的比值介于17．4％-26．1％之间。     

How the disadvantaged appraise group-based exclusion: The path from legitimacy to illegitimacy

Although many forms of differential treatment based on group membership are perceived to be legitimate, disadvantaged group members’ responses to discrimination have been studied primarily in contexts in which such treatment is appraised as illegitimate. This has resulted in an impoverished understanding of differential group-based treatment and a failure to illuminate the processes by which discrimination can shift from being seen as legitimate to being viewed as illegitimate. We discuss the determinants of disadvantaged group members’ legitimacy appraisals and the de-legitimisation process, whereby forms of discrimination appraised as legitimate come to be increasingly perceived as illegitimate. Whether group-based exclusion is addressed collectively or individually depends on socio-structural factors such as the pervasiveness of discrimination, impermeability of intergroup boundaries, and the availability of cognitive alternatives to the status quo. We conclude that understanding the antecedents and consequences of legitimacy appraisals is necessary to develop a comprehensive account of disadvantaged group members’ experiences of group-based discrimination.     

Discordance in Recovery Between Altered Locomotion and Muscle Atrophy Induced by Simulated Microgravity in Rats

Exposure to a microgravity environment leads to adverse effects in motion and musculoskeletal properties. However, few studies have investigated the recovery of altered locomotion and muscle atrophy simultaneously. The authors investigated altered locomotion in rats submitted to simulated microgravity by hindlimb unloading for 2 weeks. Motion deficits were characterized by hyperextension of the knees and ankle joints and forward-shifted limb motion. Furthermore, these locomotor deficits did not revert to their original form after a 2-week recovery period, although muscle atrophy in the hindlimbs had recovered, implying discordance in recovery between altered locomotion and muscle atrophy, and that other factors such as neural drives might control behavioral adaptations to microgravity.