Tensile strength and fracture of a tilt grain boundary in cubic SiC: A first-principles study

The ab initio tensile test has been applied to the non-polar interface of the {122}, Sigma = 9 tilt boundary in cubic SiC, where the tensile strength and mechanical behaviour at zero temperature are examined using the ab initio pseudopotential method based on the local density-functional theory. This interface is strong because of the reconstruction of interfacial bonds. The maximum tensile stress in the unaxial extension normal to the interface is about 42 GPa, which is about 80% of the theoretical and experimental values of the strength of bulk crystal along the <111> direction. Young's modulus and the fracture toughness are also comparable with the values of the bulk crystal. The back Si-C bond of the interfacial C-C bond is broken first because the C-C bond has a high strength and a short length like a diamond bond. Then the interfacial Si-C bonds are broken, and finally the Si-Si bond. The Si-C bonds are rapidly stretched and broken if the bond stretching exceeds about 20%, and the bond charge clearly disappears when the bond stretching exceeds about 30%. Changes in the electronic structure associated with the bond breaking are analysed.     

Dislocation core structures in GaN grown on Si(111) substrate

The Ga-N bond extension and compression at the cores of different types of dislocation in hexagonal GaN films grown on Si(111) substrates have been studied by high-resolution transmission electron microscopy. The relative bond extension and compression are about 6 4 and 7 4% respectively around the cores of mixed dislocations and about 9 6 and 12 7% respectively around the cores of pure edge dislocations. The core structure of a pure edge dislocation is an eightfold atom-column ring.     

There is a fire burning in my heart: The role of causal attribution in affect transfer

The role of causal attribution in affect transfer of primes was addressed by examining the consequences of explicit evaluation of primes within the framework of the affect misattribution procedure (AMP; Payne, Cheng, Govorun, & Stewart, 2005). We reasoned that affect transfer occurs when primed affect remains diffuse and not bound to a specific object, hence capable of freely colouring subsequent evaluations of ambiguous objects. Accordingly, we propose that when people explicitly evaluate the prime, affect is clearly bound to the prime and becomes less capable of influencing subsequent judgements. Supporting this notion, affect transfer in the AMP was observed when participants ignored the primes, thereby keeping the primed affect relatively unbound. However, this effect disappeared when participants explicitly evaluated the primes before target stimuli were presented. Implications of these findings in determining how and when affect arising from one object carries over to another is discussed.     

Modification of depth and distance perception caused by long-term wearing of left-right reversing spectacles

For 35 to 39 days, four observers wore continuously left-right reversing spectacles which pseudoscopically reverse the order of binocular disparity and direction of convergence. In three tests, we investigated how the visual system copes with the transformation of depth and distance information due to the reversing spectacles. In stereogram observation, after a few days of wearing the spectacles. the observers sometimes perceived a depth order which was opposite to the depth order that they had perceived in the pre-spectacle-wearing period. Monocular depth cues contributed more to depth perception in the spectacle-wearing period than they did in the pre-spectacle-wearing period. While the perceived distance significantly decreased during the spectacle-wearing period, we found no evidence of adaptive change in distance perception. The results indicate that the visual system adapts itself to the transformed situation by not only changing the processing of disparity but also by changing the relative efficiency of each cue in determining apparent depth.     

Emotions Evoked by Viewing Pictures may Affect Temporal Aspects of Visual Processing

We examined how impression (such as safety, pleasantness, and impact), as well as emotional arousal and valence, evoked by viewing a picture affects temporal resolution of visual processing and perceived picture duration. In the first experiment as an index of temporal resolution of visual processing, we measured the noticeable duration of a monochrome picture after presenting a color picture. In the second experiment, we measured the duration of the picture presentation, which was equivalent to the duration of the presentation of a gray rectangle that should not evoke specifically safe or pleasant impressions. We found that the minimum duration in which an observer could notice a monochrome image in viewing a dangerous picture was shorter than that in viewing safe pictures. We also found that observers overestimated the duration of the picture presentation in viewing dangerous pictures. However, there was no significant correlation between the results of the two experiments. These results suggest that the basis for improvement of the temporal resolution in visual processing differs from that for the elongation of the perceived duration.     

Asymptotic distributions of the estimators of communalities in factor analysis

Asymptotic distributions of the estimators of communalities are derived for the maximum likelihood method in factor analysis. It is shown that the common practice of equating the asymptotic standard error of the communality estimate to the unique variance estimate is correct for standardized communality but not correct for unstandardized communality. In a Monte Carlo simulation the accuracy of the normal approximation to the distributions of the estimators are assessed when the sample size is 150 or 300. This study was carried out in part under the ISM Cooperative Research Program (90-ISM-CRP-9).     

Writing errors and anosognosia in amyotrophic lateral sclerosis with dementia

Amyotrophic lateral sclerosis (ALS) with dementia (ALS-D) is known to exhibit characteristics of frontotemporal dementia. However, in clinical situations, it is often difficult to evaluate their cognitive functions because of impaired voluntary speech and physical disabilities. In order to identify characteristic and diagnostic cognitive symptoms of relatively advanced ALS-D patients, we retrospectively reviewed the clinical features of seven cases of clinically definitive ALS who had dementia, impaired voluntary speech, and physical disability. Their medical records showed that six out of seven patients made writing errors, and all of the patients demonstrated anosognosia. The writing errors consisted of paragraphia such as substitution, omission, or syntactic errors with individual differences in error types. Dissociation between kana and kanji were also observed. Anosognosia was evaluated by a self-rating scale with which the patients and the medical staff evaluated the patient's physical ability; the results indicated a large discrepancy between the evaluation by the patients and the medical staff. We emphasize that aphasic writing errors have been underestimated, particularly in ALS-D patients with impaired voluntary speech. We also reported that anosognosia was the most important and quantifiable symptom in ALS-D. The relationship between writing errors and anosognosia should be investigated further.     

Mutual liking and meta‐perception accuracy

The present study investigated the underlying mechanism yielding a positive correlation between dyad members' mutual liking and meta‐accuracy (i.e., dyad members who like each other tend to be accurate in judging how their partner sees them). Two pilot studies were first conducted to confirm the presence of the positive correlation. The main study was conducted to test several possible explanations for the observed positive correlation. In the main study, each participant took part in a series of brief interactions with an unacquainted opposite‐sex partner three times. In each interaction, participants rated their liking for the partner, evaluated their impression of the partner on 15 items, and finally inferred the partner's impression of them on the same 15 items. The meta‐accuracy was operationally defined as the correlation between the partner's impression and the participant's inference. Neither of the two types of unilateral liking (i.e., participant's liking for the partner nor the partner's liking for the participant) predicted meta‐accuracy. However, when both members found the partner likeable (i.e., mutual liking was present), the within‐dyad average meta‐accuracy tended to be high. The implications of these results for meta‐perception research are discussed on the basis of Brunswik's lens model framework. Copyright © 2008 John Wiley & Sons, Ltd.     

Illusory temporal order for stimuli at different depth positions

We used four experiments to examine how the perceived temporal order of two visual stimuli depends on the depth position of the stimuli specified by a binocular disparity cue. When two stimuli were presented simultaneously at different depth positions in front of or around a fixation point, the observer perceived the more distant stimulus before the nearer stimulus (Experiments 1 and 2). This illusory temporal order was found only for sudden stimulus presentation (Experiment 3). These results suggest that a common processing, which is triggered by sudden luminance change, underlies this illusion. The strength of the illusion increased with the disparity gradient and the disparity size (Experiment 4). We propose that this illusion has a basis in the processing of motion in depth, which would alert the observer to a potential collision with an object that suddenly emerges in front of the observer.     

Computational models of inductive reasoning using a statistical analysis of a Japanese corpus

Existing computational models of human inductive reasoning have been constructed based on psychological evaluations concerning the similarities or relationships between entities. However, the costs involved in collecting psychological evaluations for the sheer number of entities that exist mean that they are prohibitively impractical. In order to avoid this problem, the present article examines three types of models: a category-based neural network model, a category-based Bayesian model, and a feature-based neural network model. These models utilize the results of a statistical analysis of a Japanese corpus computing co-occurrence probabilities for word pairs, rather than using psychological evaluations. Argument strength ratings collected by a psychological experiment were found to correlate well with simulations for the category-based neural network model.