A first-principles study of the formation of θ′′ phase in Al–Cu alloys

The θ′′-Al₃Cu phase plays an important role in the precipitation process of Al–Cu alloys. This phase has a sandwich structure—every two {200}_Cu layers are separated by three {200}_Al layers. To analyse the formation mechanism of this structure, the elastic strain energy of the {200}_Cu and {200}_Al layers, and the chemical bonding energy that reflects the interaction between the electrons in Cu and neighbouring Al atoms are calculated and analysed by first-principles calculations, projected density of states and Bader analysis. Our computation results reveal that this sandwich structure is energetically preferred in the competition of elastic strain and chemical bonding energies. To minimise the elastic strain energy of {200}_Al and {200}_Cu layers, the {200}_Cu layers prefer being apart from each other, whereas the chemical bonding energy favours the opposite arrangement because the intermetallic bond between Al and Cu atoms may form through p-d hybridization.     

Perceptions of Stress,Coping, and Intervention Preferences among Caregivers of Disadvantaged Children with Asthma

Asthma remains the most prevalent chronic illness among children. Despite the substantial body of literature examining children with asthma, few studies have examined parents’ perspectives of the condition and experiences of caregiver stress. Parents of children with chronic illnesses experience elevated stress and may have limited opportunities to cope with complex emotions while caring for children with asthma. Drawing from focus groups and interviews with African American and Hispanic parents of children with asthma, this qualitative study was conducted as part of a patient-centered engagement process to inform the refinement of an intervention aimed at reducing stress among parents of children with asthma. All data were transcribed and underwent three waves of inductive analysis. The content analysis indicated that the unpredictable nature of asthma and the caregiving burden associated with managing children’s asthma contributed to parents’ stress, and external contexts compounded the impact of these stressors. Parents also reported having difficulty identifying how they coped with stress and employed approaches to coping with stress that they applied intermittently but encountered several barriers to enacting known or available coping strategies. Analyses also revealed that parents desired a multimodal stress reduction intervention that emphasized building relationships, allowed for flexibility, and encouraged staff-parent communication. Whereas African American and Hispanic parents’ experiences of stress and coping strategies were similar, their preferences differed in regards to incorporating technology into the intervention, the credentials of facilitators, and the salience of language preferences. Understanding the complexities of stressors facing caregivers is important for developing interventions to support parents and children coping with asthma, and in particular when working with families from diverse backgrounds.     

浅论道教内丹的“三要件”理论——以《性命圭旨》为例

道教炼丹术,可以区分为炼外丹和炼内丹两类。在外丹产生以前,人们把那种以五金八石为药物炼制所谓长生不死仙丹的方术,叫炼丹术。内丹产生以来,仍然沿用外丹术语,把以人体精、气、神为药物炼制仙丹的过程也叫炼丹术。但为了区分起见,通常把这种人体内的炼养称为内丹术,而把原来以矿物为原料的炼丹术叫做外丹术。又因为外丹所谓炼丹主要指从矿物质中提取金银,因此外丹术又称为外丹黄白术(“黄白”为黄金白银的隐语)。而药物、鼎炉、火候,则是外丹术炼丹的必备条件,内丹继续沿用这些术语,并把它作为内丹炼养的“三大要件”,用来比喻内丹炼养的…     

The relationships between parenting stress,parenting behaviour and preschoolers' social competence and behaviour problems in the classroom

Young children develop social and emotional competence through interactions with others in the two major contexts in which they spend time: home and preschool. This study examined whether parenting stress in the home context is related to the children's behaviour while in preschool. Previous research has suggested that parenting stress negatively influences parenting behaviour, which in turn has been shown to impact children's development. This study examined the direct relationship between parenting stress and children's behaviour in two types of preschool programmes: private day care centres and Head Start. Parenting stress was significantly related to teacher ratings of social competence, internalizing behaviours, and externalizing behaviours, and the effects of parenting behaviour do not appear to mediate this relationship. Parenting stress was most strongly related to children's social competence. Parents' reports of expectations for their child's behaviour appear to weakly moderate the relationship between externalizing behaviour and parenting stress. This study suggests that examination of a parent's level of stress, in addition to parenting practices, may be important in research and interventions with preschool children's behaviour and social competence. Copyright © 2005 John Wiley & Sons, Ltd.     

人造物概念的表征：功能、意图和目的论的解释

以概念结构研究从“相似”到“解释”的理论转向为背景,评述人造物领域的“意图-历史论”（Bloom, 1996）,提出人造物概念结构中自上而下的约束是来自“使用目的”而不是“设计意图”。分析近期报告的大量实验,最后提出人造物概念表征的“基于使用的目的论”的解释模式和人造物归类的双重目标模型。     

序列学习中的内隐学习效应

该研究采用较为复杂的包含图形出现的位置规则和顺序规则的实验材料,通过对比被试直接测验和间接测验、内隐学习和外显学习成绩的异同,考察了序列学习中的内隐学习效应,并探讨了规则特点对内隐学习效应的影响。结果表明,在图形位置的序列学习中存在内隐学习效应,内隐学习效应的大小受规则特点的影响。     

用不同外部表征方式集中呈现信息条件下的因果力判断

在分别用文字陈述、表格和图形三种外部表征方式集中呈现因果信息的条件下,用直接估计因果力大小的实验范式考察单一因果关系因果力估计的特点,检验概率对比模型,效力PC理论和pCI规则。让287名大学生被试估计不同化学药物影响动物基因变异的能力。结果发现,对单一因果关系因果力估计具有以下4个特点：⑴不对称性：在预防原因条件下的因果力估计较多符合效力PC理论,而在产生原因条件下的因果力估计一般符合概率对比模型;⑵文字陈述、表格和图形三种信息外部表征方式,不影响产生原因条件下的因果力估计,但影响预防原因条件下的因果力估计。在预防原因条件下,与文字陈述和表格表征相比,图形表征会促使更多被试按效力PC理论来做因果力估计;⑶没有被试使用pCI规则;⑷被试估计因果力所使用的规则存在明显的个体差异。     

A Structural Equation Model for the School Reinforcement Survey Schedule: Italian and American Early Adolescents

The School Reinforcement Survey Schedule (SRSS) was administered to 2,828 boys and girls in middle schools in the United States and an Italian translation was administered to 342 boys and girls in middle schools in Northern Italy. An exploratory factor analysis using half the American data set was performed using maximum likelihood estimation with a promax rotation. This analysis produced a structural equation model with six interpretable latent variables. This analysis was confirmed by results demonstrating a good fit with the other half of the American sample and separately with the Italian sample. Scores for the six latent variables were constructed and information about the distribution of scores was obtained. Multiple comparisons of the means were performed by gender, within each national sample, for each of the six latent variables. American and Italian girls report obtaining greater enjoyment from a wider variety of school activities compared to American and Italian boys.     

认知过程中的捆绑问题--认知神经科学的研究

捆绑问题是当前脑科学研究中的主要问题之一,近来已成为意识争论的焦点。该文结合国外对捆绑问题研究的最新成果,在概括介绍关于捆绑机制的主要理论的基础上,综述了捆绑问题与主要认知功能关系的研究,并指出不同认知过程中捆绑脑机制的精细化研究和一般性捆绑脑机制的系统化研究可能是今后这方面研究的重点。     

心理资本、学习策略与大学生学业成绩的关系

该研究采用《大学生学习策略问卷》和《积极心理资本问卷》对大学生4种学习策略和12种次级策略以及大学生的心理资本情况进行了调查,并在此基础上考察了大学生学习策略、心理资本与其学业成绩的关系。结果显示：大学生对认知、元认知、动机情感以及资源管理等4种学习策略总体掌握较好;在12种次级策略中,大学生对情绪调节、环境选择、过程监控等策略的掌握较好,而对意志努力、准备复述、学业求助等策略的掌握相对薄弱。大学生的心理资本总体情况是正面的,但也有约17%的大学生的心理资本水平偏低。大学生的心理资本和学习策略对其学业成绩有显著的预测作用,其中心理资本对其学业成绩的影响以学习策略为中介。