Linear-parabolic shift of initially sharp interface in AB diffusion couple above the ordering temperature

It is shown that initially sharp interface in AB diffusion couple, above the ordering temperature, can shift with anomalous kinetics, i.e. deviations from the parabolic growth kinetics are possible. The initial slopes of the shift versus time functions can be even unity for large diffusion asymmetry (the ratio of diffusion coefficients of the parent materials in orders of magnitude) and gradually decrease to 0.5 at larger distances (longer times). This is in accordance with earlier results obtained in phase separating systems. It is shown that from the results of simulations the crossover thickness, X*, between the linear and parabolic regimes can also be calculated, and the applicability of the linear–parabolic law is confirmed. Furthermore, it is illustrated that the crossover thickness depends exponentially on the diffusion asymmetry parameter, with the exponent close to the value obtained from analytical estimations.     

Art and life: Models for understanding music

Book Information Science, Truth, and Democracy. By Philip Kitcher. Oxford. New York. 2001. Pp. xiii + 219. US$27.50.     

Some recommended statistical analytic practices when reliability generalization studies are conducted

Precursors of the reliability generalization (RG) meta‐analytic approach have not established a single preferred analytic method. By means of five real RG examples, we examine how using different statistical methods to integrate coefficients alpha can influence results in RG studies. Specifically, we compare thirteen different statistical models for averaging reliability coefficients and searching for moderator variables that differ in terms of: (a) whether to transform or not the coefficients alpha, and (b) the statistical model assumed, distinguishing between ordinary least squares methods, the fixed‐effect (FE) model, the varying coefficient (VC) model, and several versions of the random‐effects (RE) model. The results obtained with the different methods exhibited important discrepancies, especially regarding moderator analyses. The main criterion for the model choice should be the extent to which the meta‐analyst intends to generalize the results. RE models are the most appropriate when the meta‐analyst aims to generalize to a hypothetical population of past or future studies, while FE and VC models are the most appropriate when the interest focuses on generalizing the results to a population of studies identical to those included in the meta‐analysis. Finally, some guidelines are proposed for selecting the statistical model when conducting an RG study.     

Implementation of Cognitive Therapy for PTSD in routine clinical care: Effectiveness and moderators of outcome in a consecutive sample

ObjectiveTrauma-focused psychological treatments are recommended as first-line treatments for Posttraumatic Stress Disorder (PTSD), but clinicians may be concerned that the good outcomes observed in randomized controlled trials (RCTs) may not generalize to the wide range of traumas and presentations seen in clinical practice. This study investigated whether Cognitive Therapy for PTSD (CT-PTSD) can be effectively implemented into a UK National Health Service Outpatient Clinic serving a defined ethnically mixed urban catchment area.MethodA consecutive sample of 330 patients with PTSD (age 17–83) following a wide range of traumas were treated by 34 therapists, who received training and supervision in CT-PTSD. Pre and post treatment data (PTSD symptoms, anxiety, depression) were collected for all patients, including dropouts. Hierarchical linear modeling investigated candidate moderators of outcome and therapist effects.ResultsCT-PTSD was well tolerated and led to very large improvement in PTSD symptoms, depression and anxiety. The majority of patients showed reliable improvement/clinically significant change: intent-to-treat: 78.8%/57.3%; completer: 84.5%/65.1%. Dropouts and unreliable attenders had worse outcome. Statistically reliable symptom exacerbation with treatment was observed in only 1.2% of patients. Treatment gains were maintained during follow-up (M = 280 days, n = 220). Few of the selection criteria used in some RCTs, demographic, diagnostic and trauma characteristics moderated treatment outcome, and only social problems and needing treatment for multiple traumas showed unique moderation effects. There were no random effects of therapist on symptom improvement, but therapists who were inexperienced in CT-PTSD had more dropouts than those with greater experience.ConclusionsThe results support the effectiveness of CT-PTSD and suggest that trauma-focused cognitive behavior therapy can be successfully implemented in routine clinical services treating patients with a wide range of traumas.     

Post‐event information presented in a question form eliminates the misinformation effect

This study investigated the influences of sentence surface forms on the misinformation effect. After viewing a film clip, participants received a post‐event narrative describing the events in the film. Critical sentences in the post‐event narrative, presented in either a statement or a question form, contained misinformation instead of questions with embedded false presuppositions; thus participants did not have to answer questions about the original event. During the final cued‐recall test, participants were informed that any relevant information presented in the post‐event narrative was not in the original event and that they should not report it. Consistent with previous findings, Experiment 1 demonstrated that post‐event information presented as an affirmative statement produced the misinformation effect. More importantly, post‐event information presented in a question form, regardless of whether it contained a misleading or studied item, increased the recall of correct information and reduced false recall. Experiment 2 replicated the main finding and ruled out an alternative explanation based on the salience of misleading items. Post‐event information presented in a question form created a condition similar to that which produces the testing effect.     

Need for closure and heuristic information processing: The moderating role of the ability to achieve the need for closure

In contrast to the ample research that shows a positive relationship between the need for closure (NFC) and heuristic information processing, this research examines the hypothesis that this relationship is moderated by the ability to achieve closure (AAC), that is, the ability to use information‐processing strategies consistent with the level of NFC. Three different operationalizations of heuristic information processing were used: recall of information consistent with the impression (Study 1); pre‐decisional information search (Study 2); and stereotypic impression formation (Study 3). The results of the studies showed that there were positive relationships between NFC and heuristic information processing when participants assessed themselves as being able to use cognitive strategies consistent with their level of NFC (high AAC). For individuals with low AAC, the relationships were negative. Our data show that motivation–cognition interactions influence the information‐processing style.     

Predictors of quality of life enjoyment and satisfaction in individuals living with HIV and AIDS in a resource-constrained setting in South Africa

The burden of HIV disease is concentrated in sub-Saharan Africa, particularly in South Africa (SA). Whilst there have been many studies conducted on the biomedical and socio-psychological aspects of HIV and AIDS, insufficient attention has been paid to the quality of life of those infected with the virus. The primary purpose of the study was to determine the predictors of quality of life enjoyment and satisfaction (Q-LES) among individuals infected with HIV. A battery of questionnaires, which included the Hospital Anxiety and Depression Scale (HADS) and the Quality of Life Enjoyment and Satisfaction Questionnaire (Q-LES-Q), were administered to 121 participants. Data was analysed using SPSS. Of the total sample (n = 121), 74% were females. The study found that a large proportion (49.5%) of the sample within the age group 25–49 years old experienced psychological distress. Those who were not on antiretroviral treatment (ART) were significantly affected (66%). Psychological distress was significantly prevalent among HIV positive individuals and also the strongest predictor of Q-LES among these individuals.     

The relationship between employees’ experience of performance management and work engagement within a South African organisation

The study investigated the relationship between employees’ experience of performance management and work engagement. Participants were a convenience sample of employed adults (N=202; females=59%, middle management?=?48%, White?=?54%, tenure more than 9 years?=?48%) in an organisation in the vehicle and asset-based finance industry. They completed the Performance Management Questionnaire (PMQ) and Utrecht Work Engagement Scale (UWES). Multiple regression analysis was used to determine the proportion of variance of work engagement that is explained by employees’ experience of performance management. Results revealed that only empowerment significantly predicted work engagement. These findings suggest that when employees experience performance management as empowering, they are also likely to have higher levels of work engagement.     

Psychological strengths and subjective well-being in South African white students

This study investigated the role of individual resources, notably self-efficacy, gratitude, and hope, in subjective well-being of white dormitory students at a historically white institution of higher learning. Using a convenience sample of white students (N?=?227), we tested the role of generalised self-efficacy, gratitude, and hope as indicators of a latent factor, labelled personal resources, in a structural equation model with subjective well-being as the latent output variable, measured by self-esteem and satisfaction with life. Path analyses indicated a reasonable fit between the data and our hypothesised theoretical model which proposed positive relations between levels of generalised self-efficacy, gratitude, dispositional hope, self-esteem and satisfaction with life. White students were psychologically doing well, considering above-midpoint levels obtained for levels of generalised self-efficacy, gratitude, dispositional hope, and satisfaction with life However, scores obtained for self-esteem and adult dispositional hope were below the mid-point and neutral respectively, indicating that White students do not agree that they experience high levels of these two psychological strengths. White female students experienced higher levels of hope, gratitude, and life satisfaction, while no significant gender differences were found for generalised self-efficacy and self-esteem. The results of this study highlight the potential for using psychological strengths to promote well-being in racially diverse students.