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1.
A novel concept for selection of alloying elements based on diffusional and thermodynamic interactions is proposed. A general model to predict enhancement or reduction of diffusion flux of an element arising from the addition of another is described and specifically applied to determine the appropriate ternary alloying addition to reduce the fast precipitation kinetics observed in binary Ti–Fe based alloy. It is experimentally shown that addition of Cr and Mo decreases the kinetics of precipitation of TiFe, whereas addition of Ta and Nb enhances the kinetics, which is consistent with the predictions of the proposed model. 相似文献
2.
Vohs JL Hetrick WP Kieffaber PD Bodkins M Bismark A Shekhar A O'Donnell BF 《Journal of abnormal psychology》2008,117(1):119-131
Schizophrenia (SZ) occurs among a spectrum of disorders with similar characteristics, including schizotypal personality disorder (SPD). Visual processing disturbances have been reported in both disorders, but it is not yet clear which processes are disturbed in both SZ and SPD, suggestive of a common endophenotype, and which appear only in SZ. In order to address this question, the authors evaluated visual event-related potentials (ERPs) elicited during a line-orientation discrimination task in control, SPD, and SZ participants. Visual ERPs allow specification of both the time course and physiological correlates of visual perception and cognition. SZ patients had smaller P100 and P300a amplitudes and prolonged P300b latency compared to the control group. SZ patients also had smaller N160, N200, P300a, and P300b amplitudes compared to the SPD group. SPD participants did not differ from control participants on any ERP measure. These data documented pervasive abnormalities in visual perception and attention in SZ but not in SPD, suggesting that these visual ERP disturbances may not represent a common endophenotype. 相似文献
3.
Hayden EP Bodkins M Brenner C Shekhar A Nurnberger JI O'Donnell BF Hetrick WP 《Journal of abnormal psychology》2008,117(1):164-170
Dysregulation in behavioral activation system (BAS) activity has been implicated in the pathogenesis of bipolar disorder (BPD). To characterize BAS activity and related facets in this disorder, the authors compared 59 participants with BPD to 44 controls on multiple measures of BAS activity, including a standardized behavioral task, self-reports, and electroencephalographic indexes of regional cortical activity. Levels of putative BAS activity differed depending on assessment strategy. When a behavioral task indexing reward sensitivity was used, euthymic BPD patients showed evidence of higher BAS activity than either control participants or patients who were in a mood episode. Following a mood induction procedure designed to elicit BAS activity, currently episodic patients showed relatively greater left anterior cortical activity than either euthymic or control participants. Implications of the findings for future research on BPD vulnerability are described. 相似文献
4.
Brown SM Kieffaber PD Carroll CA Vohs JL Tracy JA Shekhar A O'Donnell BF Steinmetz JE Hetrick WP 《Brain and cognition》2005,58(1):94-108
Accumulating evidence indicates that individuals with schizophrenia manifest abnormalities in structures (cerebellum and basal ganglia) and neurotransmitter systems (dopamine) linked to internal-timing processes. A single-cue tone delay eyeblink conditioning paradigm comprised of 100 learning and 50 extinction trials was used to examine cerebellar timing circuits in 13 medicated patients with schizophrenia and 13 age- and sex-matched controls. Patients with schizophrenia showed impaired learning of the conditioned response compared to controls and also greater within-subject variability in the timing of their responses. These findings are consistent with models of schizophrenia in which timing deficits underlie information-processing abnormalities and clinical features of the disorder. 相似文献
5.
Intercultural development in global employees will aid organizations to function successfully in the current global work scene. However, there is a need for a psychometrically valid and reliable measure, which can be used by practitioners and academics to assess the capabilities of individuals. This vignette based intercultural development scale was conceived on the basis of Bennett’s developmental model of intercultural sensitivity. The content was generated using interviews with international employees and subject matter experts. Psychometric properties were established with both qualitative and quantitative analysis. A sample of 461 international employees was used to test the validity of the scale. Confirmatory factor analysis, reliability analysis and construct validity was established with cosmopolitanism and openness to experience scales. The study confirms the scale’s dimensionality and established convergent, discriminant and nomological validity. The applications of this scale in building capabilities, talent management and strategic decisions in both practical and theoretical assessment are outlined. 相似文献
6.
Society generally encourages individuals to forgive their transgressors because forgiveness can yield many psychological, physiological, and social benefits (Exline & Baumeister, 2000 ). Nevertheless, victims face barriers to forgiving others, and other people face obstacles that prevent them from encouraging victims to forgive. We aim to provide insight into the various barriers that deter forgiveness by examining the role of the various parties involved—victims, transgressors, and uninvolved third parties—in creating barriers to forgiveness. We contend that beliefs held by these various parties significantly reduce the likelihood that victims will forgive their transgressors. By identifying how these beliefs impede forgiveness, we can begin to understand more fully why convincing victims to forgive is often a challenge. In our discussion, we also suggest ways by which victims, transgressors, and third parties can overcome these barriers to forgiveness. 相似文献
7.
We address the issue of children's understanding of abstract words with two studies on preschoolers' knowledge of the time-duration words minutes, hours, days, and years. The first study examines 4- and 5-year-olds' ability to answer questions about durations of common phenomena with duration terms. The second study examines 4- to 6-year-olds' comprehension of duration terms with a forced-choice pointing task. Both show that preschoolers' knowledge of such words is incomplete, but that it adheres to the pattern proposed in previous work with toddlers for abstract words. More specifically, children form lexical domains for such words even before they know their individual meanings, thereby allowing the children to often respond appropriately but not usually correctly to questions about abstract dimensions like time. 相似文献
8.
Christine A. Carroll Brian F. O’Donnell Anantha Shekhar William P. Hetrick 《Brain and cognition》2009
Schizophrenia may be associated with a fundamental disturbance in the temporal coordination of information processing in the brain, leading to classic symptoms of schizophrenia such as thought disorder and disorganized and contextually inappropriate behavior. Although a variety of behavioral studies have provided strong evidence for perceptual timing deficits in schizophrenia, no study to date has directly examined overt temporal performance in schizophrenia using a task that differentially engages perceptual and motor-based timing processes. The present study aimed to isolate perceptual and motor-based temporal performance in individuals diagnosed with schizophrenia using a repetitive finger-tapping task that has previously been shown to differentially engage brain regions associated with perceptual and motor-related timing behavior. Thirty-two individuals with schizophrenia and 31 non-psychiatric control participants completed the repetitive finger-tapping task, which required participants to first tap in time with computer-generated tones separated by a fixed intertone interval (tone-paced tapping), after which the tones were discontinued and participants were required to continue tapping at the established pace (self-paced tapping). Participants with schizophrenia displayed significantly faster tapping rates for both tone- and self-paced portions of the task compared to the non-psychiatric group. Individuals diagnosed with schizophrenia also displayed greater tapping variability during both tone- and self-paced portions of the task. The application of a mathematical timing model further indicated that group differences were primarily attributable to increased timing – as opposed to task implementation – difficulties in the schizophrenia group, which is noteworthy given the broad range of impairments typically associated with the disorder. These findings support the contention that schizophrenia is associated with a broad range of timing difficulties, including those associated with time perception as well as time production. 相似文献
9.
Lowry CA Johnson PL Hay-Schmidt A Mikkelsen J Shekhar A 《Stress (Amsterdam, Netherlands)》2005,8(4):233-246
Anxiety is a complex emotional state associated with sustained heightened autonomic and behavioral arousal and an increase in avoidance behavior. Anxiety-related behavior is a form of risk assessment behavior that is associated with a level of uncertainty or unpredictability regarding the outcome of emotionally salient events, often when both rewarding and aversive outcomes are possible. In this review, we highlight recent advances in our understanding of the neural circuits regulating anxiety states and anxiety-related behavior with an emphasis on the role of brainstem serotonergic systems in modulating anxiety-related circuits. In particular, we explore the possibility that the regulation of anxiety states and anxiety-related behavior by serotonergic systems is dependent on a specific, topographically organized mesolimbocortical serotonergic system that originates in the mid-rostrocaudal and caudal parts of the dorsal raphe nucleus. 相似文献
10.
Spencer C. Evans Geoffrey M. Reed Michael C. Roberts Patricia Esparza Ann D. Watts João Mendonça Correia Pierre Ritchie Mario Maj Shekhar Saxena 《International journal of psychology》2013,48(3):177-193
This study examined psychologists' views and practices regarding diagnostic classification systems for mental and behavioral disorders so as to inform the development of the ICD‐11 by the World Health Organization (WHO). WHO and the International Union of Psychological Science (IUPsyS) conducted a multilingual survey of 2155 psychologists from 23 countries, recruited through their national psychological associations. Sixty percent of global psychologists routinely used a formal classification system, with ICD‐10 used most frequently by 51% and DSM‐IV by 44%. Psychologists viewed informing treatment decisions and facilitating communication as the most important purposes of classification, and preferred flexible diagnostic guidelines to strict criteria. Clinicians favorably evaluated most diagnostic categories, but identified a number of problematic diagnoses. Substantial percentages reported problems with crosscultural applicability and cultural bias, especially among psychologists outside the USA and Europe. Findings underscore the priority of clinical utility and professional and cultural differences in international psychology. Implications for ICD‐11 development and dissemination are discussed. 相似文献