环境雌激素双酚A对成年小鼠学习记忆和突触结构的影响*

双酚A (bisphenol, BPA)是一种广泛存在的环境内分泌干扰物,它可与雌激素受体结合干扰内源性雌激素对中枢神经系统的调控作用。本研究通过将10周龄小鼠灌胃染毒BPA (0.4、4、40 mg/kg/day)3个月,研究长期BPA暴露对成年小鼠记忆行为和突触可塑性的影响。开场行为测试结果表明, BPA (0.4、4、40 mg/kg/day)增加雄性的站立次数和理毛频率, BPA (4 mg/kg/day)却显著减少雌鼠的站立次数。水迷宫和被动回避行为模型检测显示, BPA主要损伤雄鼠的空间学习记忆和被动回避记忆。通过制备海马CA1区超薄切片后,电镜观测发现, BPA (0.4、40 mg/kg/day)暴露降低雄鼠海马CA1区突触数密度,缩短雄鼠突触前活性带长度,减小雄鼠突触后致密体(PSD)厚度,增加雄鼠突触间隙宽度。进一步用Western blot方法检测突触前、后的标志性蛋白Synapsin I和PSD95以及兴奋性氨基酸NMDA受体NR1亚基和AMPA受体GluR1亚基蛋白的表达,发现BPA暴露致雄鼠Synapsin I、PSD95、NR1蛋白表达水平下调。而BPA对雌鼠的记忆行为、突触形态、突触蛋白和受体蛋白均没有明显作用。以上结果提示长期B PA暴露性别特异性地影响成年小鼠的活动性和探究行为,损伤雄鼠的学习记忆,这些作用可能通过下调突触蛋白和NMDA受体的表达而负性影响突触结构可塑性,最终影响雄鼠的学习记忆功能。     

The key role of nanoscale surface facets on the mechanical strength and failure of wurtzite and periodically twinned zinc-blende nanowires

Using molecular dynamics, we study the role of the surface facets of III–V nanowires on their failure during tensile deformation. We find that wurtzite (WZ) nanowires can withstand higher levels of stress and strain at failure compared to zinc-blende (ZB) nanowires. We observe that it is easier to nucleate a crack on a ZB nanowire due to the stress singularities that occur at the intersection of two opposing {111} facets. In WZ nanowires, we observe that cracks always nucleate at the intersection between two adjacent {112} surface facets. We explain these phenomena using fracture mechanics techniques based on energetics of crack formation.     

GP zone formation without quenched-in vacancies in Al–12 wt% Mg alloy

Dissolution of GP zones, formed in aged Al–12?wt%?Mg alloy at ?15 and 24°C, occurs during primary dilatometric and calorimetric tests, but the effect disappears after secondary tests, at low heating and cooling rates (1–2°C/min). After a?new holding at the above temperatures, GP zones again form and β and β′ phases precipitate. The results suggest the formation of GP zones without the presence of quenched-in vacancies.     

Students' Personality Traits and Learning Approaches

This study examined students' usage of deep and surface approaches to learning as well as the relationship between students' personality attributes and their approaches to learning. Participants were 284 undergraduate education students registered with a South African regular university (females = 195, males = 89). They completed the Revised two-factor Study Process Questionnaire (R-SPQ-2F) (Biggs, Kember, & Leung (2001) and Eysenck Personality Questionnaire (EPQ) (Eysenck & Eysenck, 1975, 1985). Data were analysed for differences in proportion endorsing learning approach type (deep, surface) and the association between learning approach and personality attributes. The students self-reported to use predominantly deep learning strategies and lower rather than high surface strategies. The personality attributes of Extraversion and Neuroticism were unrelated to self-reported primary learning strategy.     

Holistic processing of shape cues in face identification: Evidence from face inversion,composite faces,and acquired prosopagnosia

According to a classical functional architecture of face processing (Bruce & Young, 1986), sex processing on faces is a parallel function to individual face recognition. One consequence of the model is thus that sex categorization on faces is not influenced by face familiarity. However, the behavioural and neuro-psychological evidences supporting this dissociation are yet equivocal. To test the independence between sex processing on faces and familiar face recognition, familiar (learned) faces were morphed with new faces, generating facial continua of visual similarity to familiar faces. First, a pilot experiment shown that subjects familiarized with one extreme of the face continuum roughly perceive one half of the continuum (60 to 100% of visual similarity to familiar faces) as made of familiar faces and the other part as unfamiliar. In the experiment proper, subjects were familiarized with faces and tested in a sex decision task made on faces at the different steps of the continua. Subjects were significantly quicker at telling the sex of faces perceived as familiar (60-100%), and the effect was not observed in a control (untrained) group. These results indicate that familiar face representations are activated before sex categorization is completed, and can facilitate this processing. The nature of the interaction between sex categorization on faces and familiar face recognition is discussed.     

The impact of surface acting on coworker-directed voluntary workplace behaviours

The effects of emotional labour, that is, managing one’s emotions for work, not only predict a range of intrapersonal and organizational outcomes but can also spillover to affect non-work relationships. Despite this, relatively little is known about whether the performance of surface acting affects behaviours towards more proximal organizational members, how this occurs, and the role of supportive relationships in influencing this relationship. In this article, we examine the relationships between surface acting, state positive and negative affect, and co-worker support on co-worker-directed interpersonal behaviours in the workplace. Survey data collected at multiple time points suggest a moderated mediation model, in which surface acting interacts with co-worker support to influence employees’ voluntary behaviours through state affect. Specifically, our findings suggest that surface acting increases subsequent engagement in deviance behaviours by increasing the experience of negative affective states, especially when co-worker support is low. Surface acting also decreases the subsequent engagement of organizational citizenship behaviour through decreasing the experience of positive affective states. We conclude with a discussion of how surface acting can consequently lead to negative spirals in the organization and the implications of this for practice.     

Making Sense of Dynamic Systems: How Our Understanding of Stocks and Flows Depends on a Global Perspective

Stocks and flows (SF) are building blocks of dynamic systems: Stocks change through inflows and outflows, such as our bank balance changing with withdrawals and deposits, or atmospheric CO₂ with absorptions and emissions. However, people make systematic errors when trying to infer the behavior of dynamic systems, termed SF failure, whose cognitive explanations are yet unknown. We argue that SF failure appears when people focus on specific system elements (local processing), rather than on the system structure and gestalt (global processing). Using a standard SF task (n = 148), SF failure decreased by (a) a global as opposed to local task format; (b) individual global as opposed to local processing styles; and (c) global as opposed to local perceptual priming. These results converge toward local processing as an explanation for SF failure. We discuss theoretical and practical implications on the connections between the scope of attention and understanding of dynamic systems.     

小学儿童规则发现的类比迁移研究

本研究以小学儿童为被试,证实了在策略提示条件下解决规则发现(合取规则和析取规则)的类比问题时,任务难度和表面相似性是影响策略的迁移的重要因素,并且发现小学儿童的思维能力存在着较大的个体差异.他们在问题解决时主要使用单维检验策略,多数小学儿童缺乏较强的元认知监控.     

先天性红-绿色觉异常者的非彩色表色色差辨别研究

该文就先天性红－绿色觉异常者对非彩色系表色色差的辨别展开了研究。结果表明,先天性红－绿色觉异常者色差识别的量值△Ｅ随目视评价的等级不同而异;先天性红－绿色觉异常者与色党正常者在非彩色表色辨别上存在一定的差异;同一明度等级上、下限的变化对先天性红－绿色觉异常者的非彩色表色辨别存在影响,这种影响与明度的级别有关。