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.     

Distorted Reflections: Media Exposure and Latino Adolescents' Conceptions of Self

Because Latinos are underrepresented and often negatively stereotyped in the media, concern is frequently expressed that repeated exposure to these portrayals may reflect poorly on Latino adolescents' self-esteem. To test this issue empirically, we conducted 2 studies examining associations between multiple dimensions of self-esteem and several forms of media use. Testing 40 Latino high school students in Study 1, we found that more frequent and more active TV viewing was associated with lower social and appearance self-esteem. Many of these general patterns were replicated in Study 2 with 115 college students and with several demographic controls. Additional analyses of possible moderators revealed more consistent negative correlations among women and among participants with a stronger Latino ethnic identity. Together, these findings provide powerful evidence of a potential link between media use and the self-conceptions of Latino youth.     

Reviews of current books

Pastoral Psychology -     

Problematic Facebook Use in Adolescents: Associations with Parental Attachment and Alienation to Peers

Facebook is, nowadays, the most used social networking site worldwide and adolescents are increasingly engaging in this form of communication. Despite increasing attention of researchers to computer-mediated communication, there are few studies using an interpersonal and family relationships perspective on how adolescents relate to the Internet, and particularly to Facebook use. The aim of the present study was to test whether peer alienation mediates the link between parental attachment and problematic Facebook use. To this purpose we used a sample of 761 adolescents (53.7% boys, mean age?=?15.8), from the North region of Portugal. We also tested if the mediational model was invariant for boys and girls. The results showed that peer alienation plays a mediating role in the relationship between parental attachment and problematic Facebook use. The mediational models were, however, not invariant for boys and girls. Considering parental attachment, quality of emotional bond directly predicted problematic Facebook use only for boys. These results provide relevant clues for understanding predictors of problematic Facebook use in adolescents and also enlighten psychological intervention, particularly in parental education and school intervention programs.     

Does Money Buy Immigrant Happiness?

The relationship between income and happiness for international immigrants has been relatively unexplored. A handful of cross-sectional studies has shown that income and happiness are positively correlated after migration, and that wealthier immigrants are more satisfied with their post-migration lives than are their less privileged peers. What is unclear is if the link between income and happiness remains positive as immigrants assimilate to life in a new country. This question is the focus of our study. Using longitudinal data from over 10,000 immigrants tracked up to 30 years in the German Socio-Economic Panel Survey, we set out to provide some insight into the long-term relationship between immigrants’ self-reported life satisfaction and the level of their income in its absolute form. Longitudinal analyses revealed that immigrants who experienced increases in income over time reported greater satisfaction with life and that the income-happiness link remained relatively stable over time. The effect of absolute income on immigrants’ happiness was, nevertheless, small. We also observed that country of origin played an important role in the post-migration association between income and happiness. Income was a stronger predictor of the life satisfaction of immigrants from poorer origins than it was for their wealthier counterparts.     

Psychological Change in Everyday Life: An Exploratory Study

The innovative moments model was used in a pilot study that aimed to explore the change processes involved in everyday change outside psychotherapy. According to this model, the emergence and development of innovative moments (IMs) as exceptions to a problematic pattern are closely associated with psychological change. A longitudinal design covering 4 months of interviews was implemented with 13 adults who were coping with significant personal problems without clinical psychopathological complaints. Semistructured interviews were used to explore participants' personal accounts of their problems, and change was assessed using a scaling task at the end of the study. A total of 114 interviews were analyzed using the innovative moments coding system. A general linear model showed that higher levels of change were associated with higher proportions of complex IMs over time. Moreover, lower levels of change were associated with an increase in elementary IMs. These results support the idea that successful psychological change in everyday life shares similarities with the change pattern found in psychotherapy using the innovative moments model.     

“Interest in the service of that which is disinterested.” Józef Tischner’s anthropologico-ethical project of work

This paper focuses on one of Tischner’s last and little-known essays on the issues concerning work in the era of free market and the hegemony of the laws of economic calculation. In a discussion with Dominique Méda and André Gorz, Tischner diagnoses various threats to contemporary forms of work. Tischner criticizes above all the one-sided—that is, only objective—conception of today’s work. Referring to his own and original anthropologico-ethical project of work, the Polish scholar draws the reader’s attention to the need to promote the subjective model of work to be construed as interhuman dialogue. In work, thus construed, Tischner discerns a guarantee of the moral order of contemporary societies. His anthropological-ethical concept of work successfully inscribes itself in some of the models of work of the future, which are very much promoted today.