Anisotropic thermal properties of single-wall-carbon- nanotube-reinforced nanoceramics

Dense single-wall-carbon-nanotube-(SWCNT)-reinforced alumina nanocomposites have been fabricated by a novel spark-plasma-sintering technique. Anisotropic thermal properties have been found in carbon nanotube composites. The introduction of ropes of SWCNTs gives rise to a decrease in the transverse thermal diffusivity with increasing carbon nanotube content while it does not change the in-plane thermal diffusivity. This is scientifically interesting and technologically important for the development of materials for novel thermal barrier coatings.     

Thermodynamics of void nucleation in nanoparticles

The nucleation of voids at the initial stage of hollow nanoshell formation is described in terms of the thermodynamics of nucleation in systems of finite size (or small systems) pumped with vacancies by interdiffusion-driven vacancy influx. Crossovers from suppressed nucleation to metastable nucleus formation and then to stable nucleus formation are analysed, describing, in particular, the possibility of significant supersaturations with vacancies of the metallic core. It is shown that at higher temperatures it becomes more favourable to nucleate at once a large single void instead of multiple tiny voids.     

Making the future memorable: The phenomenology of remembered future events

Although our ability to remember future simulations conveys an adaptive advantage, enabling us to better prepare for upcoming events, the factors influencing the memorability of future simulations are not clear. In this study, participants generated future simulations that combined specific people, places and objects from memory, and for each trial, made a series of phenomenological ratings about the event components and the simulation as a whole. Memory for simulations was later assessed using a cued-recall test. We used multilevel modelling to determine whether the phenomenological qualities of event components (familiarity, emotionality and significance) and simulations (detail, plausibility) were predictive of whether the simulation was successfully encoded and later accessible. Our results demonstrate that person familiarity, detail and plausibility were significant predictors of whether a given future simulation was encoded into memory and later accessible. These findings suggest that scaffolding future simulations with pre-existing episodic memories is the path to a memorable future.     

Is Fear of Crime Mainly Social and Economic Insecurity in Disguise? A Multilevel Multinational Analysis

Using the 2006 Eurobarometer data (representative sample of the European population, N = 16 306, 27 countries), we performed a multilevel analysis aimed at predicting fear of crime. A significant proportion of the variation in fear of crime was at country level. Of the individual predictors included, being a woman, being poorly educated, being unemployed, and being an urban dweller showed positive relations with fear of crime. Fear was highest among people who considered themselves to be socially marginal, among people with negative expectations regarding themselves and their country's future, and among people who considered their nation's welfare system to be unsatisfactory. Among the ecological predictors we took into consideration, nations' degree of economic inequality and low expenditure on education and on social protection showed a positive association with fear of crime, whereas the crime, immigration, and employment rates did not. Implications and limitations of this research are discussed. Copyright © 2013 John Wiley & Sons, Ltd.     

Salutary effect of daily coping self-efficacy: impact on day-by-day coping to mood effects within dyads following hematopoietic stem cell transplantation

ABSTRACT

Background and Objectives: Little is known how coping self-efficacy (CSE) interacts with coping in dyad everyday life. The present study examined the moderating role of daily CSE in the relationship between coping and the next-day positive (PA) or negative (NA) affect in patient-caregiver dyads, following hematopoietic stem cell transplantation.

Design: This intensive longitudinal study was conducted during the first 28 days after post-transplant discharge.

Methods: Patients and their caregivers (N?=?200) maintained daily diaries on CSE, coping strategies, and affect.

Results: Daily CSE moderated daily coping–affect relationship: Positive emotion-focused coping increased PA in patients with higher than usual emotion-related CSE, whereas a buffering effect was found at lower than usual emotion-related CSE. A positive association between negative emotion-focused coping and NA in both patients and caregivers was stronger among those with lower than usual levels of emotion-related CSE. Higher than usual instrumental coping reduced NA in patients whose caregivers had higher than usual problem-related CSE, but increased NA for those whose caregivers had lower than usual instrumental CSE.

Conclusion: The findings show that daily CSE contributes to the effectiveness of daily coping within dyad, confirming its significance in effective adaptation and the role in the dyadic coping process.     

Using Rasch modelling to examine the international personality item pool (IPIP) values in action (VIA) measure of character strengths

This paper investigates the psychometric properties of the values in action (VIA) character strengths (Peterson and Seligman, 2004 Peterson, C., & Seligman, M. E. P. (2004). Character strengths and virtues: A handbook and classification. Oxford, United Kingdom: Oxford University Press. [Google Scholar]). A sample of 904 South African undergraduate students (female=77%, male=23%, black=70%, mean age=21.07 years, SD age=2.73 years) was assessed using a 380-item questionnaire that included the items from the international personality item pool (IPIP) values in action (VIA) measure of 24 character strengths as well as additional items based on the underlying theory of the particular constructs. Responses were analysed with the Rasch rating scale model. Reliability coefficients were computed for the retained scale items. The majority (21) of the scales demonstrated satisfactory Rasch model fit and good reliability of scores. The finding that a large proportion of strengths exhibited differential item functioning for at least one of (1) gender, (2) ethnicity and (3) home language group, challenges the assumption that character strengths are necessarily accultural, indicating qualitative distinctions in construct conceptualisations and measurement as a function of emic factors.     

Age Differences in Day-To-Day Speed-Accuracy Tradeoffs: Results from the COGITO Study

We examined adult age differences in day-to-day adjustments in speed-accuracy tradeoffs (SAT) on a figural comparison task. Data came from the COGITO study, with over 100 younger and 100 older adults, assessed for over 100 days. Participants were given explicit feedback about their completion time and accuracy each day after task completion. We applied a multivariate vector auto-regressive model of order 1 to the daily mean reaction time (RT) and daily accuracy scores together, within each age group. We expected that participants adjusted their SAT if the two cross-regressive parameters from RT (or accuracy) on day t-1 of accuracy (or RT) on day t were sizable and negative. We found that: (a) the temporal dependencies of both accuracy and RT were quite strong in both age groups; (b) younger adults showed an effect of their accuracy on day t-1 on their RT on day t, a pattern that was in accordance with adjustments of their SAT; (c) older adults did not appear to adjust their SAT; (d) these effects were partly associated with reliable individual differences within each age group. We discuss possible explanations for older adults’ reluctance to recalibrate speed and accuracy on a day-to-day basis.     

A Bayesian Approach to More Stable Estimates of Group-Level Effects in Contextual Studies

Multilevel analyses are often used to estimate the effects of group-level constructs. However, when using aggregated individual data (e.g., student ratings) to assess a group-level construct (e.g., classroom climate), the observed group mean might not provide a reliable measure of the unobserved latent group mean. In the present article, we propose a Bayesian approach that can be used to estimate a multilevel latent covariate model, which corrects for the unreliable assessment of the latent group mean when estimating the group-level effect. A simulation study was conducted to evaluate the choice of different priors for the group-level variance of the predictor variable and to compare the Bayesian approach with the maximum likelihood approach implemented in the software Mplus. Results showed that, under problematic conditions (i.e., small number of groups, predictor variable with a small ICC), the Bayesian approach produced more accurate estimates of the group-level effect than the maximum likelihood approach did.     

It Takes a Village: The Effects of 10th Grade College-Going Expectations of Students, Parents, and Teachers Four Years Later

Adolescents are surrounded by people who have expectations about their college-going potential. Yet, few studies have examined the link between these multiple sources of college-going expectations and the actual status of students in postsecondary education years later. The study draws on data collected in the 2002–2006 Educational Longitudinal Study and employs an underutilized statistical technique (cross-classified multilevel modeling) to account for teacher reports on overlapping groups of students (typical of high school research). Results showed that positive expectations of students, parents, English, and mathematics teachers in the 10th grade each uniquely predicted postsecondary status 4 years later. As a group, the four sources of expectations explained greater variance in postsecondary education than student characteristics such as socioeconomic status and academic performance. This suggests positive expectations are additive and promotive for students regardless of their risk status. Teacher expectations were also found to be protective for low income students. Implications for future expectancy research and equity-focused interventions are discussed.