Yielding and strain hardening in aluminium single-crystal foils subjected to tension and bending

A series of tensile and microbend tests were conducted on aluminium single-crystal foil specimens with different thicknesses ranging from 20 to 90?µm. Two different crystal orientations relative to the tensile direction were considered in the tests: one is an orientation that was excepted to activate at least four slip systems on four different slip planes, and the other is an orientation that was expected to activate only a single-slip system. In the tensile tests, typical size dependence of initial yield strength was observed. The microbend test method was extended to include a reversal of bending direction. Using the curves of bending moment normalized by the square of foil thickness versus surface strain, which were obtained from the reversed bending tests, the total amounts of strain hardening were divided into isotropic and kinematic hardening components. In the microbend tests, a pronounced size-dependent kinematic hardening behaviour was clearly observed; meanwhile, the amounts of isotropic hardening were very small, particularly for the single-slip orientation.     

Tailoring of interfaces in amorphous silicon–germanium multilayers on the atomic scale by ultra-high gravity

Amorphous Si/Ge multilayers containing diffuse interfaces have been prepared, heated in an ultra-centrifuge and subsequent interface structure modifications observed by X-ray reflectivity. The thickness of the Si/Ge and Ge/Si interface zones became asymmetrical owing to various effects occurring on the different atoms parallel to the direction of gravity-induced diffusion. The technique could prove useful for tuning physical (electronic, magnetic or optical) properties of layered structures.     

Conscientiousness mediates the relation between perceived parental socialisation and self‐rated health

The pathways between parenting behaviours, personality and physical health have all been separately studied. Prior research has paid little attention to the indirect effects of personality in the path between parenting behaviours and better health. The purpose of this study was to explore the mediational effects of conscientiousness on the relationships between parental socialisation of responsibility and self‐rated health, and to examine potential age differences in this mediational pathway. In total, 736 female and 749 male members across Japan participated in this study. They were divided into three groups by age category: younger‐, middle‐aged and older‐aged. Conscientiousness and health were concurrently rated, while parental socialisation of responsibility was retrospectively assessed. Our analyses revealed that parental socialisation of responsibility is positively associated with conscientiousness and self‐rated health, that conscientiousness is positively associated with self‐rated health, and that conscientiousness fully mediated the effect of parental socialisation of responsibility on self‐rated health. The mediational links were consistent across younger, middle‐aged and older‐aged cohorts. Our findings suggest that greater parental socialisation of responsibility relates to higher conscientiousness, and consequently healthier adults. These findings imply that parental behaviours could be a plausible target for intervention to foster the development of conscientiousness and better health.     

Problematic mobile phone use as impulsive choice: Development and empirical verification of a reinforcer-pathology model

Problematic mobile phone use is characterized by its “impulsive” nature; users engage in it despite their negative attitude toward it. From a behavioral-economic perspective, this attitude–behavior discrepancy is generated by competing contingencies that involve smaller-sooner social reinforcers associated with mobile phone use and larger-later prosocial reinforcers potentially compromised by phone use. Based on this conceptualization, the reinforcer-pathology model of problematic mobile phone use is proposed, which posits that such phone use stems from excessive delay discounting of the social and prosocial reinforcers and/or excessive demand for the social reinforcers. A secondary data analysis of previously published studies was conducted, with the novel addition of principal component analysis and hierarchical cluster analysis of these data. The results generated evidence that supports the reinforcer-pathology model proposed in this article. Based on the theoretical analyses and accumulated empirical evidence, theory-driven prevention and intervention strategies for problematic mobile phone use are proposed. Overall, the reinforcer-pathology model of problematic mobile phone use provides a comprehensive framework for understanding and addressing this growing issue.     

Longitudinal relations among maternal behaviors, effortful control and young children's committed compliance

In a sample (n = 235) of 30-, 42-, and 54-month-olds, the relations among parenting, effortful control (EC), impulsivity, and children's committed compliance were examined. Parenting was assessed with mothers' observed sensitivity and warmth; EC was measured by mothers' and caregivers' reports, as well as a behavioral task; impulsivity was assessed by mothers' and caregivers' reports; and committed compliance was observed during a cleanup and prohibition task, as well as measured by adults' reports. Using path modeling, there was evidence that 30-month parenting predicted high EC and low impulsivity a year later when the stability of the outcomes was controlled, and there was evidence that 30- and 42-month EC, but not impulsivity, predicted higher committed compliance a year later, controlling for earlier levels of the outcomes. Moreover, 42-month EC predicted low impulsivity a year later. Fixed effects models, which are not biased by omitted time-invariant variables, also were conducted and showed that 30-month parenting still predicted EC a year later, and 42-month EC predicted later low impulsivity. Findings are discussed in terms of the importance of differentiating between effortful control and impulsivity and the potential mediating role of EC in the relations between parenting and children's committed compliance.     

Age, clutter, and competitive selection

Modern theory explains visual selective attention as a competition for receptive fields in the extrastriate cortex. The present study examined whether this competition contributes to older adults' difficulty in processing visual clutter. In 2 experiments, young and older adult subjects made same-different judgments of target shapes in displays with or without clutter. The target shapes were either high or low in discriminability. The spatial separation between targets varied across trials, and the effects of competitive selection were gauged through decrements in task performance that resulted as separation decreased. Both age groups showed a competition-in-clutter effect, evincing a stronger influence of target separation within cluttered displays. However, the costs of clutter in general and the strength of the competition-in-clutter effect more specifically were both substantially larger for older adults. Effects of clutter and competition also varied with stimulus discriminability; judgments of highly discriminable stimuli evinced no intertarget competition in uncluttered displays for either age group, while judgments of less discriminable stimuli showed competition whether clutter was present or not. Results suggest that clutter disproportionately degrades older adults' visual performance by forcing more careful stimulus resolution, engendering stronger competition for selection. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

Serum levels of brain-derived neurotrophic factor (BDNF), BDNF gene Val66Met polymorphism, or plasma catecholamine metabolites, and response to mirtazapine in Japanese patients with major depressive disorder (MDD)

Object We investigated an association between the polymorphism of brain-derived neurotrophic factor (BDNF) gene Val66Met and the response to mirtazapine in Japanese patients with major depressive disorder (MDD). We also examined mirtazapine's effects on the serum BDNF and plasma levels of catecholamine metabolites in these patients. METHODS: Eighty-four patients who met the DSM-IV-TR criteria for MDD were treated with only mirtazapine for 4 weeks. The BDNF Val66Met polymorphism was detected by direct sequencing in the region, and serum BDNF levels and plasma levels of catecholamine metabolites were measured by ELISA and HPLC-ECD, respectively. RESULTS: Mirtazapine treatment for 4 weeks significantly increased serum BDNF levels in the responders, whereas nonresponders showed significant decreases. No association was found between either of the two genotypes (Val/Val vs. Met-carriers) and the response to mirtazapine at T4 or the serum BDNF levels at T0. Mirtazapine did not alter the plasma levels of homovanillic acid (HVA) or 3-methoxy-4-hydroxyphenylglycol (MHPG). Discussion The dynamics of serum BDNF levels, but not plasma levels of HVA and MHPG, reflect the response to mirtazapine treatment; the BDNF Val66Met polymorphism in patients with depression is, however, associated with neither a particular response to mirtazapine treatment nor baseline serum BDNF levels. Conclusion Serum BDNF levels, but not plasma levels of HVA or MHPG, and BDNF Val66Met polymorphism are related to the mirtazapine response in MDD.     

Self‐Esteem and Justice Orientation as Moderators for the Effects of Individual‐Targeted and Group‐Targeted Justice

Drawing on the self‐interest and moral virtues perspectives of justice, we examine how self‐esteem and justice orientation as individual difference factors moderate the effects of individual‐targeted and group‐targeted justice on helping behaviors and intention to leave. A scenario‐based study was conducted using a total sample of 624 Japanese undergraduate students. The results highlighted the difference between the moderating roles of self‐esteem and justice orientation. Self‐esteem moderated the effect of individual‐targeted procedural justice on intention to leave such that the effect was stronger when self‐esteem was high. In contrast, justice orientation mainly moderated the effects of group‐targeted procedural and distributive justice on helping behaviors such that the effects were weaker when justice orientation was high. Implications of our findings and future research directions are discussed.     

Bidirectional influences between maternal parenting and children's peer problems: a longitudinal monozygotic twin difference study

This twin study examined the bidirectional relationship between maternal parenting behaviors and children's peer problems that were not confounded by genetic and family environmental factors. Mothers of 259 monozygotic twin pairs reported parenting behaviors and peer problems when twins were 42 and 48 months. Path analyses on monozygotic twin difference scores revealed that authoritative parenting (the presence of consistent discipline and lack of harsh parenting) and peer problems simultaneously influenced each other. Authoritative parenting reduced peer problems, and peer problems increased authoritative parenting. Neither consistent discipline nor harsh parenting alone was associated with peer problems. These results suggest that maternal authoritative parenting works protectively in regard to children's peer problems, and peer problems can evoke such effective parenting.     

Changes in Muscle Activity in Response to Assistive Force during Isometric Elbow Flexion

Abstract

This study investigated the muscle activity and force variability in response to perturbation of assistive force during isometric elbow flexion. Sixteen healthy right-handed young men (age: 22.0?±?1.1?years; height: 171.9?±?4.8?cm; weight 68.4?±?11.2?kg) were recruited and the muscle activity of biceps brachii and triceps brachii were assessed using surface electromyography. Workload force and assistive force applied on isometric elbow flexion significantly affected the changes in both biceps and triceps muscle activities. A higher assistive force was shown to result in reduced biceps muscle activity compared to the unassisted period. In contrast, the efficiency of the assistive force acting on the biceps decreased as the assistive force increased. In general, the force variability of the biceps muscle remained approximately the same at lower workload force conditions than that at higher workload force conditions. In conclusion, higher assistive force may not yield a higher performance efficiency in human-assistive force interaction.