Atomic arrangement at the 3C-SiC/Si(001) interface revealed utilising aberration-corrected transmission electron microscope

The atomistic structure of the 3C-SiC/Si(001) interface has been investigated using a combination of aberration-corrected transmission electron microscopy and a newly developed image processing method for eliminating artificial contrast. The structures having periods four times longer than those of the silicon lattice have been observed distinctly in images taken along both Si[110] and Si[100] directions. Contrary to theoretical models proposed previously, the interface of the three-dimensional structural model that we constructed on the basis of our experiments has a silicon-rich configuration. We have clarified that the strain field induced by the two-dimensional misfit between Si(001)-(4?×?4) and SiC(001)-(5?×?5) is relaxed by the two-dimensional network of misfit dislocations; simple edge dislocations with [100] and [010] directions and Lomer dislocations with [110] and [110] directions. The atomistic structures of the Lomer dislocations have been also clarified.     

The effects of a brief time perspective intervention for increasing physical activity among young adults

Past research has demonstrated that health behavior is correlated with time perspective: long-term thinkers are more likely than short-term thinkers to engage in health protective behaviors and less likely to engage in health damaging behaviors. To date, however, no research has experimentally demonstrated that time perspective is causally related to health behavior. We designed a brief (three 1/2-h weekly sessions) time perspective intervention to enhance long-term thinking about physical activity and examined its efficacy among two samples of young adults who signed up for fitness classes at a university recreational facility. Participants were assigned to one of three conditions: time perspective intervention, goal-setting control intervention, and no-treatment control. In Study 1, physical activity levels were assessed at preintervention, at postintervention (3 weeks later), and at 10-week follow-up (7 weeks after completion of the intervention). Controlling for preintervention physical activity levels, time perspective participants reported increased levels of physical activity relative to both other groups at postintervention, and relative to the no-treatment group at 10-week follow-up. This study provides the first experimental evidence that the effects of health behavior interventions may be enhanced by increasing participants’ long-term time perspective, and that time perspective is causally associated with health behavior. Study 2 replicated some of the effects of Study 1 using a larger sample, a six-month follow-up interval, and improved measurement of outcome. Together Studies 1 and 2 suggest that time perspective is an important ingredient in interventions designed to promote physical activity.     

Mixed emotions: Holistic and analytic perception of facial expressions

In the face literature, it is debated whether the identification of facial expressions requires holistic (i.e., whole face) or analytic (i.e., parts-based) information. In this study, happy and angry composite expressions were created in which the top and bottom face halves formed either an incongruent (e.g., angry top + happy bottom) or congruent composite expression (e.g., happy top + happy bottom). Participants reported the expression in the target top or bottom half of the face. In Experiment 1, the target half in the incongruent condition was identified less accurately and more slowly relative to the baseline isolated expression or neutral face conditions. In contrast, no differences were found between congruent and the baseline conditions. In Experiment 2, the effects of exposure duration were tested by presenting faces for 20, 60, 100 and 120 ms. Interference effects for the incongruent faces appeared at the earliest 20 ms interval and persisted for the 60, 100 and 120 ms intervals. In contrast, no differences were found between the congruent and baseline face conditions at any exposure interval. In Experiment 3, it was found that spatial alignment impaired the recognition of incongruent expressions, but had no effect on congruent expressions. These results are discussed in terms of holistic and analytic processing of facial expressions.     

Executive function in young children and chimpanzees (Pan troglodytes): evidence from a nonverbal dimensional change card sort task

In this article the authors compared chimpanzees' executive function with that of children. They developed a nonverbal dimensional change card sorting task, which indexed the development of executive function. Three pairs of mother and offspring chimpanzees and 30 typically developed 5-year-old children were presented with 2 target stimuli and a test stimulus comprising 2 dimensions (size and shape) on a display; they were required to sort the test stimulus according to 1 dimension (e.g., shape). After 5 consecutive correct trials, the participants had to sort the test stimulus according to the other dimension (e.g., size). The results showed that the chimpanzees often failed to sort the test stimuli according to the first and reversed dimensions. On the other hand, the children were correctly able to use both dimensions. These results indicate that chimpanzees may have less developed executive skills than children.     

The brain basis of the phonological deficit in dyslexia is independent of IQ

Although the role of IQ in developmental dyslexia remains ambiguous, the dominant clinical and research approaches rely on a definition of dyslexia that requires reading skill to be significantly below the level expected given an individual's IQ. In the study reported here, we used functional MRI (fMRI) to examine whether differences in brain activation during phonological processing that are characteristic of dyslexia were similar or dissimilar in children with poor reading ability who had high IQ scores (discrepant readers) and in children with poor reading ability who had low IQ scores (nondiscrepant readers). In two independent samples including a total of 131 children, using univariate and multivariate pattern analyses, we found that discrepant and nondiscrepant poor readers exhibited similar patterns of reduced activation in brain areas such as left parietotemporal and occipitotemporal regions. These results converge with behavioral evidence indicating that, regardless of IQ, poor readers have similar kinds of reading difficulties in relation to phonological processing.     

Physical intuitions about support relations in monkeys (Macaca fuscata) and apes (Pan troglodytes)

Nonhuman primates, like humans, have demonstrated various physical intuitions. Cacchione and Krist (2004) examined chimpanzees' intuitions about support relations with the violation-of-expectation task. They reported that the chimpanzees possessed intuitions about support, but their intuitions differed from those of humans in part; they were sensitive to "contact/no-contact" and "amount of contact" but not "type of contact" rule. To further explore intuitions about support in nonhuman primates, we conducted similar experiments on monkeys (Japanese monkeys) and apes (chimpanzees). In three experiments, we presented physically possible and impossible events of different support relations to the participants and measured their looking times. The results reveal that the chimpanzees and monkeys detect the violations of "contact/no-contact" and "amount of contact" but not "type of contact" variable. Therefore, the apes and monkeys possess similar intuitions; however, these intuitions differ in part from those of humans. The present study provides new and corroborative evidence of intuitions about support in nonhuman primates. However, this again leads to the question of distinctive understanding about support relations among primate species.     

Social Exclusion and Disengagement of Covert Attention from Social Signs: The Moderating Role of Fear of Negative Evaluation

Previous research has demonstrated that social exclusion motivates individuals with low fear of negative evaluation (FNE) to pay attention to signs of social acceptance, but it does not motivate individuals with high FNE to do so. However, it remains unclear whether this finding reflects overt or covert attentional bias because the researchers employed a dot‐probe task. In order to resolve this ambiguity, the present study solely assessed disengagement of covert attention from social signs after exclusion manipulation in an experiment with university students (N = 60). As a result, exclusion delayed disengagement of covert attention from facial stimuli regardless of their types of expression for participants with low FNE, but such delay was not observed for participants with high FNE. The result indicated that social exclusion enhances attention to social information in individuals with low FNE, whereas it does not in individuals with high FNE. We discuss the possibility that a decline in inclusionary status affects overt and covert attentional processes differently.     

Discrimination and categorization of photographs of natural objects by chimpanzees (Pan troglodytes)

Two experiments assessed the ability of four adult female chimpanzees to categorize natural objects. Chimpanzees were initially trained to match different color photographs of familiar objects from four possible categories. In training, all the comparison stimuli were from the same category in one condition, and from different categories in another condition. For all subjects, training performance was consistently better for the "different category" than for the "same category" trials. Probe trials were shown after training. In probe trials, the sample and positive comparison stimuli were different items from the same category, and the foils were selected from among the three other test categories. Individual performance was above chance in probe trials, suggesting that categorization by chimpanzees may transcend perceptual resemblance. These results were later replicated with novel stimulus items from the same four categories (experiment 2). Altogether, this research demonstrates that chimpanzees grouped perceptually different exemplars within the same category, and further suggests that these animals formed conceptual representations of the categories. Accepted after revision: 10 August 2001 Electronic Publication