High-pressure phase transition and lattice dynamics of rock-salt and FeSi-type phases of MgS

A phase transition of MgS under high pressure is investigated using a first-principles method. It is found from energy-volume calculations that the rock-salt (B1) phase of MgS transforms into a FeSi-type (B28) phase at 143?GPa. The calculated ground-state parameters in the B1 phase are in excellent agreement with available experimental and theoretical data. Ab initio phonon calculations are also performed to investigate the structural behaviour of MgS under high pressure. An unstable transverse acoustic mode and a phase transition from B1 to B28 phase at ~143.7?GPa driven by this soft mode are predicted. The B28 structure of MgS is stable up to 350?GPa according to lattice dynamics calculations.     

Determination of the depth distribution of subsurface damage during polishing of alumina

High-resolution grazing-incidence parallel-beam powder diffraction has been used to detect the subsurface damage below alumina surfaces subjected to polishing with cerium oxide or diamond. Despite very significant evolution of the surface morphology, no changes in the subsurface strains were observed over a 20min period of polishing with ceria. For both polishing materials, the variation with angle in the full-width at half-height maximum was successfully modelled by a strain distribution that fell exponentially with increasing depth. Although the surface amplitude and depth dependence parameter are coupled, we have been able to place upper limits on the depth to which the damage extends. Under realistic assumptions, the depth of damage induced by 1µm diamond paste is comparable with that from 3µm ceria polish.     

The orientation and temperature dependences of dislocation velocity in Ni 3 Al single crystals

The average velocities of screw dislocations in Ni 3 Al single crystals have been directly measured as a function of resolved shear stress (RSS) and orientation in the temperature domain of the flow stress anomaly using the etch-pit technique. The velocity was found to be extremely sensitive to the RSS in all cases. In contrast with ordinary metals, the screw dislocation velocities in Ni 3 Al show anomalous behaviour; under a constant RSS, the velocities decrease dramatically with increasing temperature. Furthermore, the velocities and the tension-compression asymmetry of the velocities depend on the orientation of applied stress.     

伤害回避的脑机制及其生物基础

伤害回避是指个体对厌恶刺激信号做出强烈的反应,并学会被动地回避惩罚的一种倾向,这一倾向使得个体反复思考未来的结局,并谨慎小心地对待不确定情景中的事件,进而更有可能诱发情感障碍。伤害回避涉及的神经网络包括三个子网络,即额顶叶-前扣带皮层的连接、皮层-杏仁核的连接和白质通道的结构性连接,这三个子网络分别与羞怯感-易疲劳性、预期担心以及不确定环境中的害怕情绪有关。而其生物基础则包括单一基因多态性和基因多态间的交互作用。今后的研究应该集中在深化伤害回避神经网络与生物基础间的联合机制、研究三种及以上基因多态间的交互作用、考察其他因素对基因效应的调节作用、注重伤害回避四种亚型相关神经网络之间的连接、探讨5-HT4等其他几种5-羟色胺受体多态性与伤害回避的关系以及分析伤害回避内部机制在抗抑郁治疗中的作用等方面。     

Prevalence and Predictors of Posttraumatic Growth in Accidentally Injured Patients

This study examined prevalence and predictors of posttraumatic growth in 180 accidentally injured patients of mainland China in their convalescence stage, investigating its relationships with demographic and accidental injury variables, personality, posttraumatic stress disorder (PTSD) symptoms, and coping styles. Our results showed that posttraumatic growth (PTG) presented mostly in the domain of Relating to Others and indicated that PTG was significantly related to marital status, educational level, personality, coping styles, and PTSD symptoms. Avoidance of PTSD symptoms, Openness to experience, and positive coping were significant predictors of PTG. The findings emphasize that when promoting PTG of accidentally injured patients, healthcare providers should facilitate patients utilizing personal resources, understand PTG coexists with PTSD symptoms, and adjust interventions based on the coping styles the patients have adopted.     

Mind-reading without the scanner: Behavioural decoding of working memory content

ABSTRACT

Sophisticated machine learning algorithms have been successfully applied to functional neuroimaging data in order to characterize internal cognitive states. But is it possible to “mind-read” without the scanner? Capitalizing on the robust finding that the contents of working memory guide visual attention toward memory-matching objects, we trained a multivariate pattern classifier on behavioural indices of attentional guidance. Working memory representations were successfully decoded from behaviour alone, both within and between individuals. The current study provides a proof-of-concept for applying machine learning techniques to simple behavioural outputs (e.g., response times) in order to decode information about specific internal cognitive states.     

Play it again: neural responses to reunion with excluders predicted by attachment patterns

Reunion behavior following stressful separations from caregivers is often considered the single most sensitive clue to infant attachment patterns. Extending these ideas to middle childhood/early adolescence, we examined participants' neural responses to reunion with peers who had previously excluded them. We recorded event‐related potentials among nineteen 11‐ to 15‐year‐old youth previously classified on attachment interviews (11 secure and 8 insecure‐dismissing) while they played a virtual ball‐toss game (Cyberball) with peers that involved fair play, exclusion and reunion phases. Compared to secure participants, dismissing participants displayed a greater increment in the N2 during reunion relative to fair play, a neural marker commonly linked to expectancy violation. These data suggest a greater tendency toward continued expectations of rejection among dismissing children, even after cessation of social exclusion. In turn, the link between self‐reported ostracism distress and neural signs of negative expectancy at reunion was moderated by attachment, such that self‐reports were discordant with the neural index of expectancy violation for dismissing, but not for secure children. A video abstract of this article can be viewed at http://www.youtube.com/watch?v=qzoRel5c-4s .     

Social support as a mediator of religious involvement and physical and emotional functioning in a national sample of African-Americans

Researchers propose social support as one of the factors that may explain the positive relationship often observed between religious involvement and health outcomes. African-Americans are a population that tends to have higher than average levels of religious involvement and are also disproportionately impacted by most health conditions. The present study sought to determine whether social support mediates the role of religious involvement in physical and emotional functioning and depressive symptoms, among a national probability sample of African-Americans (N = 803). Study participants completed telephone interviews. We used structural equation modelling to test hypotheses based on the theoretical model. Findings suggest evidence for a mediating role of belonging and tangible support in the association between religious behaviours and physical functioning as well as depression. There was no mediational role played by appraisal support, or for emotional functioning. Implications for faith-based health promotion interventions are discussed.     

社会认同与内、外群体态度的关系：群际威胁和群体情绪的中介作用

为探究社会认同、群际威胁和群体情绪如何同时影响内、外群体态度,本研究以中日撞船事件为考察蓝本向天津市431名大学生被试进行调查研究,结果发现：国家认同在认同威胁对两种群体态度的总影响和通过群体愤怒的间接影响中都起到负向的调节作用;群际威胁和群体情绪在社会认同与内、外群体态度之间具有显著中介作用。结论：国家认同在对群体态度的影响中起基础性作用,不同群际威胁与不同群体情绪相对应进而影响群体态度。     

教师工作压力与职业枯竭的关系：职业承诺的调节效应

应用工作压力、职业枯竭和职业承诺问卷对中小学教师2114人进行调查,主要探讨职业承诺对工作压力与职业枯竭关系的调节效应。结果发现：工作压力与职业枯竭的情绪衰竭、非人性化、认知枯竭具有显著正相关,情感承诺、规范承诺与职业枯竭具有显著负相关;教师职业承诺以及所包括的情感承诺、留职承诺、规范承诺对工作压力与职业枯竭关系具有负向调节效应;不同教龄段教师在职业枯竭不同方面存在差异。