999 research outputs found

    Impact ionization in GaAs: a screened exchange density functional approach

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    Results are presented of a fully ab-initio calculation of impact ionization rates in GaAs within the density functional theory framework, using a screened-exchange formalism and the highly precise all-electron full-potential linearized augmented plane wave (FLAPW) method. The calculated impact ionization rates show a marked orientation dependence in {\bf k} space, indicating the strong restrictions imposed by the conservation of energy and momentum. This anisotropy diminishes as the impacting electron energy increases. A Keldysh type fit performed on the energy-dependent rate shows a rather soft edge and a threshold energy greater than the direct band gap. The consistency with available Monte Carlo and empirical pseudopotential calculations shows the reliability of our approach and paves the way to ab-initio calculations of pair production rates in new and more complex materials.Comment: 11 pages, 4 figures, Submitted to Phys. Rev.

    Things change: Women’s and men’s marital disruption dynamics in Italy during a time of social transformations, 1970-2003

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    We study women’s and men’s marital disruption in Italy between 1970 and 2003. By applying an event-history analysis to the 2003 Italian variant of the Generations and Gender Survey we found that the spread of marital disruption started among middle-highly educated women. Then in recent years it appears that less educated women have also been able to dissolve their unhappy unions. Overall we can see the beginning of a reversed educational gradient from positive to negative. In contrast the trend in men’s marital disruption risk appears as a change over time common to all educational groups, although with persisting educational differentials.determinants, educational differences, event history analysis, gender difference, Italy, marital disruption

    Posttraumatic growth as positive personality change: evidence, controversies and future directions

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    This target article focuses on the construct of post-traumatic growth—positive psychological change experienced as a result of the struggle with highly challenging life circumstances. Prominent theories of post-traumatic growth define it in terms of personality change, and as a result, this area of research should be of great interest to personality psychologists. Despite this fact, most of the research on this topic has not been sufficiently informed by relevant research in personality psychology, and much of the extant research suffers from significant methodological limitations. We review the literature on post-traumatic growth, with a particular focus on how researchers have conceptualized it and the specific methodological issues associated with these conceptualizations. We outline some ways in which personality science can both be enriched by the study of this phenomenon and inform rigorous research on post-traumatic growth and provide a series of guidelines for future research of post-traumatic growth as positive personality change

    Catastrophizing mediates the relationship between the personal belief in a just world and pain outcomes among chronic pain support group attendees

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    Health-related research suggests the belief in a just world can act as a personal resource that protects against the adverse effects of pain and illness. However, currently, little is known about how this belief, particularly in relation to one’s own life, might influence pain. Consistent with the suggestions of previous research, the present study undertook a secondary data analysis to investigate pain catastrophizing as a mediator of the relationship between the personal just world belief and chronic pain outcomes in a sample of chronic pain support group attendees. Partially supporting the hypotheses, catastrophizing was negatively correlated with the personal just world belief and mediated the relationship between this belief and pain and disability, but not distress. Suggestions for future research and intervention development are made

    Diabetes Susceptibility in the Canadian Oji-Cree Population Is Moderated by Abnormal mRNA Processing of HNF1A G319S Transcripts

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    OBJECTIVE—The G319S HNF1A variant is associated with an increased risk of type 2 diabetes in the Canadian Oji-Cree population. We hypothesized that the variant site at the 3′ end of exon 4 might influence splicing and characterized mRNA transcripts to investigate the mutational mechanism underlying this susceptibility to diabetes

    Caries prevalence and tooth loss in Hungarian adult population: results of a national survey

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    <p>Abstract</p> <p>Background</p> <p>Oral health is basicly important for the well-being of people. Thus, it is strongly suggested to organize epidemiological surveys in order to gain representative data on oral condition of the given population. The purpose of the cross-sectional study was to determine the results on tooth loss and caries prevalence of Hungarian adults in different age groups.</p> <p>Methods</p> <p>Altogether 4606 persons (2923 women, 1683 men) participated in the study who were classified into different age groups: 19 [less than or equal to], 20–24, 35–44, 45–64, 65–74, [greater than or equal to]75 year olds. Probands were selected randomly from the population attending the compulsory lung screening examinations. The participants were examined by calibrated dentists, according to the WHO (1997) criteria. In order to produce representative data, the chosen localities for these examinations covered the capital, the largest towns, the villages, and case weights were used for the statistical evaluation.</p> <p>Results</p> <p>The mean values of DMF-T were found between 11.79±5.68 and 21.90±7.61 These values were significantly higher in women compared to men (p < 0.05). In all age groups the values of M were the highest. Except for the women in the groups of 35–44 and 45–64 year olds, these values showed an increasing tendency both in women and men by age (from 5.50±6.49, and 4.70±4.08 to 21.52±9.07 and 18.41±8.89 respectively). The values of D components reached the highest values in 45–64 year olds (4.54±2.12 and 4.22±2.81, by gender, respectively), then in the older age groups there was a high reduction in these values (in 65–74 year olds: 2.72±1.88 and 1.36±2.48; in 75 or more than 75 year olds: 1.05±1.41 and 1.03±1.76 by gender, respectively). The ratio of D and F values was the highest in the age group of 65–74 year olds (2.12), the lowest ratio could be calculated in 20–34 year olds (0.65).</p> <p>Data showed some decrease in caries experience in 35–44 years of age between 2000 and 2004. The prevalence of persons with 21 or more teeth had been increased from 65.6% to 73.1%. This positive tendency has not been occured in prevalence of edentulousness in this age group: the prevalence of edentulous persons changed from 1.4 to 1.9%. In 65–74 year olds the level of edentulousness became lower, from 25.9 to 14.8% and the prevalence of persons with 21 or more teeth is higher (22.6%) than it was in 2000 (13.0%).</p> <p>Conclusion</p> <p>Present data from Hungary show some slight decrease in caries experience between 35–44 years of age, although this positive tendency has not been occured in prevalence of edentulousness in this age group. A positive tendency could be experienced in the group of 65–74 year olds in edentulousness and in number of teeth, but further efforts are needed to reach a better situation.</p

    The sensory school: working with teachers, parents and pupils to create good sensory conditions

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    Purpose: An alliance of schools and researchers formed a collaborative community of practice in order to understand and improve the sensory school environment for pupils on the autistic spectrum, and incorporate the findings into school improvement planning. The paper aims to discuss this issue. Design/methodology/approach: Representatives of special and mainstream schools in South London and a team of researchers formed the project team, including an autistic researcher. The researchers and a named staff member from each of the schools met regularly over the course of 18 months in order to work on an iterative process to improve the sensory experience pupils had of the school environment. Each school completed sensory audits and observations, and was visited by members of the research team. Parents were involved via meetings with the research team and two conferences were organised to share findings. Findings: Useful outcomes included: developing and sharing of good practice between schools; opportunities for parents of autistic pupils to discuss their concerns, particularly with someone with insider perspective; and exploration of creative ways to achieve pupil involvement and the idea that good autism practice has the potential to benefit all pupils. A resource pack was produced for the schools to access. Plans are in place to revisit the initiative in 12 months’ time in order to ascertain whether there have been long-term benefits. Originality/value: Projects building communities of practice involving autistic people as core team members are rare, yet feedback from those involved in the project showed this to be a key aspect of shared learning

    The Shadows of the Past

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    We examined associations between two orientations based on historical group trauma, a form of enduring group victimhood (Perpetual Ingroup Victimhood Orientation [PIVO]) and the belief that one’s group might itself become a victimizer (Fear of Victimizing [FOV]), and attitudes, cognitions, and emotions related to intergroup conflicts. PIVO was positively and FOV was negatively related to aggressive attitudes and emotions toward the outgroup (Studies 1a-1c, Israeli–Palestinian conflict), and to the attribution of responsibility for a series of hostilities to the outgroup (Study 3, Israeli–Palestinian conflict). PIVO was negatively and FOV positively related to support for forgiveness and reconciliation (Study 2, Northern Ireland conflict). In Experimental Study 4, FOV predicted greater accuracy in remembering harm, regardless of victims’ group identity, whereas PIVO was associated with reduced accuracy only when victims were Palestinians (outgroup members). Taken together, these findings indicate that both orientations have a significant impact on intergroup conflicts and their resolution
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