Ab initio investigation of electron-phonon interaction in LaSn3 and CaSn3

ABSTRACT

We present results for the structural, electronic, vibrational, and electron-phonon coupling properties of LaSn₃ and CaSn₃ adopting the simple cubic AuCu₃-type structure obtained using the the generalised gradient approximation of the density functional theory and plane wave ab initio pseudopotential method. Our electronic results show that both materials display metallic character with several bands, which have mainly Sn 5p character, crossing the Fermi level. The calculated phonon spectrum of LaSn₃ accords very well with reported experimental measurements. The weights of the peaks in the Eliashberg spectral function of both compounds are enhanced with the use of experimental lattice constant in our electron-phonon calculation, increasing the value of average electron phonon coupling parameter from 0.876 to 0.937 for LaSn₃ (by 7%) and from 0.642 to 0.725 for CaSn₃ (by 13%). The use of experimental lattice constant also improves the agreement between theoretical and experimental values of the superconducting temperature for both compounds.     

Structure of interest in a Caribbean sample: Application of the Personal Globe Inventory

The structural validity of the Personal Globe Inventory (PGI, Tracey, 2002) as applied to a Caribbean sample of university students in Jamaica (N = 103) and Trinidad (N = 118) was examined. The fit of the data to Holland's six-type RIASEC, the PGI eight-type model, and the PGI spherical structure was examined using the randomized test of hypothesized order relations. The results demonstrated that the circular structure (i.e. RIASEC and the eight-type model), unlike the spherical structure, fits the Caribbean data well. No structural differences were found between gender and nationality. Further examination of the cultural perception of prestige in a Caribbean sample is warranted. Overall, the results support the structural validity of the PGI in Caribbean applications.     

Anxiety reactivity and anxiety perseveration represent dissociable dimensions of anxiety vulnerability: A replication and extension

Trait anxiety is a unitary construct reflecting individual differences in the tendency to experience anxious symptomatology, typically measured with questionnaires such as the Spielberger Trait Anxiety Inventory (STAI‐T). Recent research by Rudaizky, Page, and MacLeod has found evidence that two different dimensions of trait anxiety account for independent variance in trait anxiety scores. These dimensions are anxiety reactivity (AR), reflecting the probability of experiencing an anxious reaction, and anxiety perseveration (AP), reflecting the persistence of anxious symptoms once elicited. There are two key issues addressed in this study: first, the replicability of Rudaizky et al.'s findings and second, the ability of the measures of AR and AP developed by Rudaizky et al. to predict independent variance in STAI‐T scores after statistically controlling for variance shared with a measure of depression. Regression analysis determined that AR and AP do account for independent variance in STAI‐T trait anxiety scores even after statistically controlling for depression. The implications of these findings for the understanding of anxiety vulnerability are discussed.     

Exploring the Factor Structure of the Proactive Coping Inventory: A Southern African Study

This study explored the factor structure of the Proactive Coping Inventory (PCI) to determine whether its six-factor structure holds within the Southern African context. Data on proactive coping were collected from students attending three universities, one each in Botswana (n=88, females=45.5%, mean age=21.31 years, SD=2.04), Namibia (n=38, females=47.4%, mean age=24.21 years, SD=3.47) and South Africa (n=496, females=56.9%; mean age=22.27 years, SD=2.60). Exploratory factor analysis was used to determine the factor structure of the PCI. Findings suggest that the PCI is comprised of two factors: Future-Oriented Coping (comprised of Proactive Coping, Reflective Coping, Strategic Planning and Preventive Coping) and Support Seeking (comprised of Instrumental Support Seeking and Emotional Support Seeking). This is in line with theory that suggests that individuals cope by means of persisting towards goal attainment.     

The Imperatives of Narrative: Health Interest Groups and Morality in Network News

This article examines some of the story conventions of network television news to explain the ways in which healthcare interest groups develop and maintain their presence in this medium—a process that has significant implications for public understanding of healthcare issues, and therefore to bioethics. The article is divided into three sections. The first section focuses on three major normative conventions of television news: adherence to a simple narrative structure, the balance ethic, and avoidance of the “think-piece” and outlines the basic strategies available to interest groups for exploiting these normative conventions. Section two introduces three case studies of organizations and individuals who have run high-profile media campaigns. Section three explores the implications for bioethics of the observations made in this article.     

智慧:结构、类型、测量及与相关变量的关系

智慧是个体在其智力与知识的基础上,经由经验与练习习得的一种德才兼备的综合心理素质,包括聪明才智与良好品德两大成份.智慧可分为常规智慧与应变智慧、群体智慧与组织智慧、个人智慧与一般智慧、德慧与物慧等,可用三维智慧量表、自我评估智慧量表以及智慧发展量表等进行测量,并与年龄、性别、文化、教育、人格、思维方式、智力等存在重要关联.今后应该深入探究智慧的概念与结构,拓展其研究方法、测量工具与教育策略以及开展中国化研究.     

An analysis of coping profiles and adjustment in persons with rheumatoid arthritis

This study examined dispositional and situative antecedents of vigilant and avoidant coping behavior. Seventy-two subjects were classified in coping style on the basis of their responses to the vigilance and cognitive avoidance scales of the Mainz Coping Inventory (MCI, Krohne, 1989), and alternatively, on their trait anxiety and defensiveness scores (cf. Weinberger, Schwartz, & Davidson, 1979). In a subsequent laboratory task, subjects were exposed to various conditions of predictability of an aversive event. In anticipation of an aversive loud tone, coping behavior was operationally defined as choosing to listen either to a warning channel (i.e., vigilance) or instead to music (i.e., avoidance). Probability of occurrence of a warning signal while listening to the warning channel varied across trials, being either 0%, 33%, 66%, or 100%. Subjects were exposed to each level and were informed about the respective probability in advance. In general, listening to the warning channel increased with an increase in the probability of the warning signal. However, four groups of subjects who differed in their pattern of coping behavior across trials were observed: rigid-avoidant copers (always listening to music), rigid-vigilant copers (always monitoring the warning channel), flexible copers (switching from music to warning channel with increasing probability of warning), and inconsistent copers (vacillating between music and warning channel regardless of probability of warning). Coping style classifications did not show substantial associations with coping behavior. However, subjects demonstrating the inconsistent coping pattern scored high on trait anxiety.     

Measuring anxiety by ordered categorical items in data with subgroup structure: the case of the Hungarian version of the trait anxiety scale of the state-trait anxiety inventory for children (staic-h)

The present study suggests a modelling methodology for examining measurement invariance of ordered categorical item indicators of latent constructs such as anxiety, coping, motives etc., in research settings with few subgroups and a large sample of individuals. The Hungarian version of the Anxiety Trait scale of the State-Trait Anxiety Inventory for Children (STAIC-H) was administered to 605 boys and 975 girls of age 10–15 in 12 schools. A MIMIC model was suggested for examining measurement invariance across subgroups of schools and ages, while a multi-group analysis was recommended for investigating invariance across gender. High degree of invariance across groups was obtained for the Anxiety Trait scale in terms of item factor loadings, item thresholds and item homogeneity with respect to group contrast variables. Based on the diagnostic information obtained by the present methodology, the few item indicators showing non-invariance were discussed with reference to methodological and conceptual considerations.     

Knowledge-telling and knowledge-transforming arguments in mock jurors' verdict justifications

According to the “story model” a juror constructs an implicit mental model of a story telling what happened as the basis for the verdict choice. But the explicit justification of a verdict choice could take the form of a story (knowledge telling) or the form of a relational (knowledge-transforming) argument structure that brings together diverse, non-chronologically related pieces of evidence. The study investigates whether people tend towards knowledge telling or knowledge transforming, and whether use of these argument structure types are related to skilled argument and epistemic understanding. A sample of people on jury duty chose and justified verdicts in two abridged cases. Participants tended to display the same argument structure and argument skill across cases. Those using knowledge-transforming structures were more successful at the juror argument skills task and had a higher level of epistemic understanding. The discussion suggests that jurors approach their task with an epistemic orientation towards knowledge telling or knowledge transforming.     

Dissimilar effects of task‐relevant and interpersonal threat on independent–interdependent self‐construal in individuals with high self‐esteem

Previous research has indicated that individuals with high trait self‐esteem (HSEs) become more independent and less interdependent after experiencing a task‐relevant threat. However, these studies have not investigated other sources of ego threats, such as interpersonal threats. Therefore, the moderating effects of the degree of trait self‐esteem on task‐relevant and interpersonal ego threats were investigated in relation to independent, or interdependent self‐construal. It was predicted that in HSEs, the level of task‐relevant stress would be positively–negatively related to their independence–interdependence, whereas the level of interpersonal stress would be negatively–positively related to their independence–interdependence. In individuals with low trait self‐esteem (LSEs), the two types of stresses and independent–interdependent self‐construal may not have a significant relationship. We conducted a questionnaire survey with undergraduates. Correlational analysis of the results indicated that in HSEs, greater task‐relevant stress was related to heightened independence, whereas greater interpersonal stress had the opposite effect, indicating lower independence and heightened interdependence. However, these stresses were not related to the self‐construal of LSEs. These findings suggest that task‐relevant and interpersonal threat could have differential effects on independent and interdependent self‐construal for HSEs, but not in LSEs.