Linear instability signals the initiation of motion of a twin plane under load

This letter presents a study of the atomic mechanism of the initiation of motion of a static twin plane under applied mechanical load in a model shape-memory material. By tracking the deformation under load and using linear stability analysis, we find that the eigenvalues of the Hessian matrix provide an indicator of the initiation of motion of the twin plane. The initiation of motion is signaled by a linear instability and a drop in the lowest eigenvalue to zero as well as a sharp drop in higher eigenvalues. Additionally, by comparing with direct molecular dynamics, we see that the eigenmode associated with the zero eigenvalue is found to accurately predict the initial mode of motion. We also find that the initial motion occurs through the formation of a stacking fault just ahead of the existing twin plane and the broadening of the stacking fault drives further transformation.     

生物制剂治疗克罗恩病进展

克罗恩病是一种以累及消化道为主的复发性炎性疾病.生物制剂的使用为克罗恩病的治疗提供了新的方向.大量临床研究已证实生物治疗主要是抗TNF α单抗对诱导及维持克罗恩病临床缓解、预防并发症的发生有效.目前临床指南多建议对克罗恩病采取递增方案治疗,对重度患者可及早采取更为有效的包括生物治疗在内的治疗方式,但递减治疗方案在临床中的应用尤其是针对初次诊断者也越来越受到重视.目前早期及长期应用生物治疗的安全性及其是否能改变克罗恩病的自然病程证据尚不充分.应针对患者的不同情况,根据风险/效益研究来确定更合适的治疗方案.     

组织类型与员工建言行为的关系探索：基于权力的视角

研究目的是探索中国背景下国有企业、民营企业、外资企业、政府机关四类组织中员工建言行为的差异,及员工个人权力感和权力动机的中介作用。采用问卷法对员工和管理者进行配对取样调查,通过对回收的324份有效问卷进行数据分析。结果表明,员工建言行为在四种组织类型中存在显著性差异,而员工个人权力感和权力动机在其中起到中介作用。此外,研究还发现,权力距离倾向在组织类型和个人权力感之间起到调节作用。最后,研究梳理了组织类型与建言行为的关系模型,并对未来研究做了展望。     

Learning without consciously knowing: Evidence from event-related potentials in sequence learning

This paper investigated how implicit and explicit knowledge is reflected in event-related potentials (ERPs) in sequence learning. ERPs were recorded during a serial reaction time task. The results showed that there were greater RT benefits for standard compared with deviant stimuli later than early on, indicating sequence learning. After training, more standard triplets were generated under inclusion than exclusion tests and more standard triplets under exclusion than chance level, indicating that participants acquired both explicit and implicit knowledge. However, deviant targets elicited enhanced N2 and P3 components for targets with explicit knowledge but a larger N2 effect for targets with implicit knowledge, revealing that implicit knowledge expresses itself in relatively early components (N2) and explicit knowledge in additional P3 components. The results help resolve current debate about the neural substrates supporting implicit and explicit learning.     

Dialectical thinking and health behaviors: The effects of theory of planned behavior

The primary purpose of this study was to investigate whether the theory of planned behavior (TPB) mediated the relationship between dialectical thinking and health behaviors. A sample of 285 undergraduates was tested with a dialectical thinking styles scale, health promoting lifestyle profiles, and TPB questionnaires. Structural equation modeling was used for data analysis. Results indicated that all the three dimensions of thinking styles (belief in the connection, acceptance of change, and acceptance of contradiction) exerted significant effects on TPB constructs. Specifically, the connection and the change dimensions had positive effects on health behaviors mediated by TPB, whereas the contradiction dimension had a negative effect. Model 2 showed a satisfactory fit, demonstrating the influential pathways between dialectical thinking and health behaviors. Implications in issues of health promotion and future research are discussed.     

Too exhausted to remember: Ego depletion undermines subsequent event‐based prospective memory

Past research has consistently found that people are likely to do worse on high‐level cognitive tasks after exerting self‐control on previous actions. However, little has been unraveled about to what extent ego depletion affects subsequent prospective memory. Drawing upon the self‐control strength model and the relationship between self‐control resources and executive control, this study proposes that the initial actions of self‐control may undermine subsequent event‐based prospective memory (EBPM). Ego depletion was manipulated through watching a video requiring visual attention (Experiment 1) or completing an incongruent Stroop task (Experiment 2). Participants were then tested on EBPM embedded in an ongoing task. As predicted, the results showed that after ruling out possible intervening variables (e.g. mood, focal and nonfocal cues, and characteristics of ongoing task and ego depletion task), participants in the high‐depletion condition performed significantly worse on EBPM than those in the low‐depletion condition. The results suggested that the effect of ego depletion on EBPM was mainly due to an impaired prospective component rather than to a retrospective component.     

Do knee concentric and eccentric strength and sagittal-plane knee joint biomechanics differ between jumpers and non-jumpers in landing?

The purpose of this study was to investigate the differences of knee concentric and eccentric strength and impact related knee biomechanics between jumpers and non-jumpers during step-off landing tasks. Ten male college swimming athletes (non-jumpers) and 10 track and volleyball athletes (jumpers) were recruited to participate in two test sessions: a muscle strength testing session of concentric and eccentric extension for dominant knee joint at 60 °/s and 180 °/s and a landing testing session. The participants performed five trials of step-off landing in each of four conditions: soft and stiff landing from 0.4 m and 0.6 m landing heights. The three-dimensional kinematics and ground reaction force were recorded simultaneously during step-off landing conditions. The results showed that the jumpers had significantly greater peak knee eccentric extension and concentric flexion torques compared to the non-jumpers. No significant group effects were found for peak vertical ground reaction force and knee range of motion during landing. The jumpers had significantly greater knee contact flexion angle, maximum knee flexion angle and initial knee extension moment compared to the non-jumpers. These results suggest that these athletes adopted a favorable impact attenuation strategy that is related to the greater knee eccentric muscle strength and training.     

Knowledge and economic growth—creativity,learning and knowledge utilization

The purpose of this study is to discuss the dynamic interdependence of knowledge and economic growth. We show that the traditional economics, which treats knowledge as parameters and is mainly developed within linearized, stable and static frameworks can hardly explain the modern economic complexity. We argue that it is necessary to treat creativity, learning and knowledge utilization as endogenous dynamic processes of social and economic evolution. To handle with the complicated dynamic interdependence of wealth and knowledge accumulation, we need to apply genuine nonlinear dynamic theory. In particular, we discuss possible benefits of government's intervention in education and science to the society when the social and economic evolution is characterized of nonlinearity, instability and multi‐equilibria.     

How benefits of expressive writing vary as a function of writing instructions,ethnicity and ambivalence over emotional expression

Written emotional disclosure has been reported to confer a variety of benefits on physical and psychological well-being. However, variable findings suggest that outcomes may vary systematically as a function of specific parameters of the experimental design. This study aims to investigate the unique and combined effects of disclosure instructions focusing on emotional expression and instructions facilitating cognitive reappraisal and to examine how ambivalence over emotional expression and ethnicity moderate the effects of these writing instructions. Seventy-one Asian and 59 Caucasian undergraduates (N = 130) with at least minimal physical or depressive symptoms were randomly assigned to one of the four writing conditions: emotional disclosure (ED), cognitive reappraisal (COG), the combination of ED and COG, or a control condition. Self-reported physical symptoms, positive affect (PA) and negative affect were assessed at baseline and three follow-ups spanning 4 months. Mixed linear models revealed that COG writing reduced physical symptoms, ED buffered a decrease in PA over time, and the combination of ED and COG (i.e. self-regulation; SR) was most effective. Asians and highly ambivalent participants benefited most from expressive writing. Findings contribute to the development of a SR moderator model and carry implications for designing expressive disclosure studies, particularly for ethnic minorities.     

Electropulsing-induced strengthening of steel at high temperature

Electropulsing usually promotes a metastable phase to evolve towards its equilibrium state. This work reports an alternative case, where electropulsing promotes the decomposition of the stable δ-phase in duplex stainless steel at high temperature. This decomposition enables both the γ-phase and the σ-phase in the steel to survive and hence to strengthen it at high temperature. The hardness of the quenched sample with electropulsing treatment is 49.4% higher than that without electropulsing treatment. A fundamental understanding of the observation is developed.