Influence of test temperature on the size effect in molybdenum small-scale compression pillars

Previous research has shown that body-centred cubic (bcc) metals exhibit a smaller size dependence of strength than what is commonly observed in face-centred cubic (fcc) metals. This work investigates compression testing of focused ion beam-manufactured molybdenum pillars ranging in size from 300?nm to 5?μm, both above and below its critical temperature at 300 and 500?K. At 500?K the size effect is found to be consistent with what is observed in fcc metals, owing to the increased mobility of screw dislocations.     

Effect of pre-straining on the size effect in molybdenum pillars

The effect of prior deformation on mechanical behavior as a function of size is investigated for body-centered cubic (bcc) molybdenum (Mo) pillars. Experiments were performed using focused ion beam (FIB) manufactured [0 0 1] and [2 3 5] Mo micro/nanopillars, which were compressed, re-FIB machined, and compressed again. Unlike in bulk materials, pre-straining has a negligible effect on stress–strain behavior of the pillars, suggesting that dislocation storage does not occur in small-scale bcc specimens. The prevailing mechanism behind the size effect is attributed to dislocation nucleation mechanisms.     

Neighborhood consistency and memory for number facts

Verguts and Fias (Memory & Cognition 33:1-16, 2005a) proposed a new model of memory for simple multiplication facts ( $ 2 \times 3 = 6 $ ; $ 8 \times 7 = 56 $ ) in which learning and performance is governed by the consistency of a problem’s correct product with neighboring products in the times table. In the present study, to directly investigate effects of neighborhood consistency, participants memorized a set of 16 novel “pound” arithmetic equations. The pound arithmetic table included eight tie equations with repeated operands (e.g., 4 # 4 = 29) and eight nontie equations (e.g., 5 # 4 = 39). In the consistent problem set, tie and nontie answers in adjacent columns and rows shared a common decade or unit value. In the inconsistent problem set, neighboring tie and nontie problems did not share a common decade or unit. Across 14 study–test blocks, memorization of the pound arithmetic table presented a robust effect of neighborhood consistency, with the rate of learning nearly doubling that of the inconsistent condition. An analysis of error types showed that consistency fostered the development of a categorical structure based on problem operands and that tie problems were encoded as a distinct subcategory of problems. There was also a substantial learning advantage for tie problems relative to nonties both with consistent and inconsistent neighbors. The results indicate that neighborhood consistency can have a major impact on memory for number facts.     

Environmental knowledge and conservation behavior: exploring prevalence and structure in a representative sample

Knowledge is commonly seen as a necessary precondition for a person’s behavior. Consistent with this, most educational interventions rely on knowledge transfer. However, for the most efficient informational strategies for education, it is essential that we identify the types of knowledge that promote behavior effectively and investigate their structure. A questionnaire consisting of three environmental knowledge scales and a conservation behavior measure was sent to 5000 randomly selected Swiss adults. A completed questionnaire was returned by 55% of them (N=2736). A series of structural equation analyses indicates that the three knowledge forms exert different influences on conservation behavior: Action-related knowledge and effectiveness knowledge have a direct effect on performance. In contrast, system knowledge is more remote from behavior, exerting only a mediated influence on it by way of affecting the other two knowledge types.     

Psychometric Properties of the Alabama Parenting Questionnaire

  We examined the psychometric properties of a German translation of the Child Global Report version of the Alabama Parenting Questionnaire (APQ). A total of 1219 German school-children (644 boys and 575 girls), ages 10–14 years participated in the study. The APQ was subjected to exploratory and confirmatory factor analysis. Exploratory factor analysis produced five factors that were largely consistent with the a priori scale structure. These factors included dimensions of parental involvement, positive parenting, poor monitoring/supervision, inconsistent discipline, and corporal punishment. Fit indexes from confirmatory factor analyses suggested that the five factor model represented a satisfactory solution for the data, with some minor modifications in scale content. These findings provide initial support for the factorial validity of the child report version of the APQ in German families.     

Callous-unemotional features, behavioral inhibition, and parenting: independent predictors of aggression in a high-risk preschool sample

A behaviorally-uninhibited temperament, callous-unemotional (CU) features, and harsh parenting have been associated with specific patterns of aggressive behavior in older children and adolescents. We tested the additive and interactive effects of these factors in predicting different types of aggressive behavior in a high-risk preschool sample. Forty-nine preschoolers and their parents registering for Head Start programs were recruited for participation. Behavioral inhibition, CU features, and attitudes toward various types of parenting were assessed through parent rating scales completed at the time of registration. Behavioral inhibition, CU features, and aggression were assessed by teacher ratings approximately six months later. Analyses revealed that behavioral inhibition, CU features, and harsh parental attitudes all contributed independently to the prediction of aggressive behavior. These associations were strongest for proactive types of aggression. Our results suggest that a behaviorally uninhibited temperament, CU features, and attitudes favoring harsh parenting are all important for understanding the development of aggression in preschool children.     

Developmental changes of sleep spindles and their impact on sleep‐dependent memory consolidation and general cognitive abilities: A longitudinal approach

Sleep spindles are related to sleep‐dependent memory consolidation and general cognitive abilities. However, they undergo drastic maturational changes during adolescence. Here we used a longitudinal approach (across 7 years) to explore whether developmental changes in sleep spindle density can explain individual differences in sleep‐dependent memory consolidation and general cognitive abilities. Ambulatory polysomnography was recorded during four nights in 34 healthy subjects (24 female) with two nights (baseline and experimental) at initial recording (age range 8–11 years) and two nights at follow‐up recording (age range 14–18 years). For declarative learning, participants encoded word pairs with a subsequent recall before and after sleep. General cognitive abilities were measured by the Wechsler Intelligence Scale. Higher slow (11–13 Hz) than fast (13–15 Hz) spindle density at frontal, central, and parietal sites during initial recordings, followed by a shift to higher fast than slow spindle density at central and parietal sites during follow‐up recordings, suggest that mature spindle topography develops throughout adolescence. Fast spindle density increases from baseline to experimental night were positively related to sleep‐dependent memory consolidation. In addition, we found that the development of fast spindles predicted the improvement in memory consolidation across the two longitudinal measurements, a finding that underlines a crucial role for mature fast spindles for sleep‐dependent memory consolidation. Furthermore, slow spindle changes across adolescence were related to general cognitive abilities, a relationship that could indicate the maturation of frontal networks relevant for efficient cognitive processing. A video abstract of this article can be viewed at: https://www.youtube.com/watch?v=7NXJzm8HbIw and https://www.youtube.com/watch?v=iuMQY1OIJ0s     

The Latent Structure of Psychopathy in Youth: A Taxometric Investigation

Using taxometric procedures, the latent structure of psychopathy was investigated in two studies of children and adolescents. Prior studies have identified a taxon (i.e., a natural category) associated with antisocial behavior in adults as well as children and adolescents. However, features of this taxon suggest that it is not psychopathy but rather a broader class consistent with the construct of life course persistent antisocial behavior. Because the only prior study of youth used a non-clinical sample, the base rate of psychopathy may have been too low to reveal a psychopathy taxon, especially against the background of a broader and more prevalent antisocial behavior taxon. Therefore, this investigation sought to increase the likelihood of finding a psychopathy taxon (should one exist) by increasing its expected base rate through inclusion of clinical cases in the samples studied. Results produced evidence for both a broad antisocial behavior problem taxon consistent with past research and a much lower base rate taxon consistent with prevalence expectations for psychopathy. These findings support the existence of latent taxa for both psychopathy and a broader class of antisocial behavior problems. Further taxometric research appears to be warranted, which should use a broader array of indicators, with greater specificity to psychopathy.     

Callous-unemotional traits in a community sample of adolescents

This study examined the structure, distribution, and correlates of a new measure of self-reported callous-unemotional (CU) traits in 1,443 adolescents (774 boys, 669 girls) between the ages of 13 to 18 years. The Inventory of Callous-Unemotional Traits was subjected to exploratory factor analysis and confirmatory factor analysis. Exploratory factor analysis produced three factors: callousness, uncaring, and unemotional. Fit indexes suggested that the three-factor model, with a single higher-order factor, represented a satisfactory solution for the data. This factor structure fits well for both boys and girls. CU traits correlated significantly with measures of conduct problems and psychosocial impairment. Furthermore, the traits showed predicted associations with sensation seeking and the Big Five personality dimensions, supporting the construct validity of the measure of CU traits.