230 research outputs found

    Self-compensation in semiconductors: The Zn vacancy in Ga-doped ZnO

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    Self-compensation, the tendency of a crystal to lower its energy by forming point defects to counter the effects of a dopant, is here quantitatively proven. Based on a new theoretical formalism and several different experimental techniques, we demonstrate that the addition of 1.4 × 10 exp 21-cm exp −3 Ga donors in ZnO causes the lattice to form 1.7 × 10 exp 20-cm exp −3 Zn-vacancy acceptors. The calculated VZn formation energy of 0.2 eV is consistent with predictions from density functional theory. Our formalism is of general validity and can be used to investigate self-compensation in any degenerate semiconductor material.Peer reviewe

    Ceding to their appetites: A taxonomy of international tourists to South Africa

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    Tourism is a key source of income to South Africa. Food and beverages is a key part of tourism and the literature reveals that tourists spend up to a quarter of their budget on cuisine. South Africa has, however, been rated as the least-prepared culinary travel destination and the travel destination with the greatest potential for growth. Therefore, a segmentation taxonomy based on culinary preferences of international tourists to South Africa is put forth which can be used to prepare South Africa as a culinary travel destination. The 627 international tourists surveyed were divided into five segments with the use of factor analyses, t-tests, Spearman rank correlations and analysis of variance. The segments were named conservationists, experience seekers, devotees, explorers and socialisers (CEDES taxonomy). Multiple results and implications are discussed in the paper

    Corporate governance compliance and disclosure in the banking sector: using data from Japan

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    Using regression model this study investigates which characteristics of a bank is associated with the extent of corporate governance disclosure in Japan. The findings suggest that on average 8 banks out of a sample of 46 disclose optimal corporate governance information. The regression model results reveal in general that non-executive directors, cross-ownership, capital adequacy ratio and type of auditors are associated with the extent of corporate governance disclosure. Of these four variables, non-executive directors have a more significant impact on the extent of disclosure contrary to total assets and audit firms of banks in the context of Japan. The findings of this paper are relevant for corporate regulators, professional associations and developers of corporate governance code when designing or updating corporate governance code

    'Working out’ identity: distance runners and the management of disrupted identity

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    This article contributes fresh perspectives to the empirical literature on the sociology of the body, and of leisure and identity, by analysing the impact of long-term injury on the identities of two amateur but serious middle/long-distance runners. Employing a symbolic interactionist framework,and utilising data derived from a collaborative autoethnographic project, it explores the role of ‘identity work’ in providing continuity of identity during the liminality of long-term injury and rehabilitation, which poses a fundamental challenge to athletic identity. Specifically, the analysis applies Snow and Anderson’s (1995) and Perinbanayagam’s (2000) theoretical conceptualisations in order to examine the various forms of identity work undertaken by the injured participants, along the dimensions of materialistic, associative and vocabularic identifications. Such identity work was found to be crucial in sustaining a credible sporting identity in the face of disruption to the running self, and in generating momentum towards the goal of restitution to full running fitness and reengagement with a cherished form of leisure. KEYWORDS: identity work, symbolic interactionism, distance running, disrupted identit

    Is poetry therapy an appropriate intervention for clients recovering from anorexia? A critical review of the literature and client report

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    © 2017 Informa UK Limited, trading as Taylor & Francis Group. Poetry therapy is an arts-based psychotherapeutic intervention, often delivered in groups. This paper argues that the process and benefits of poetry therapy may be particularly suited to clients recovering from anorexia, as an adjunct to other treatments. Poetry therapy and its history are described briefly, and the relevance of poetry therapy for clients recovering from anorexia is outlined. After one client contributes her experience of this treatment for illustration, the paper offers a review of the evidence base for poetry therapy for eating disorders, and argues that, while research is limited, further research is warranted. Finally, a description of one form of clinical application is offered, to enable replication

    NLRX1 functions as a tumor suppressor in Pan02 pancreatic cancer cells

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    Pancreatic cancer is a deadly malignancy with limited treatment options. NLRX1 is a unique, understudied member of the Nod-like Receptor (NLR) family of pattern recognition receptors that regulates a variety of biological processes that are highly relevant to pancreatic cancer. The role of NLRX1 in cancer remains highly enigmatic, with some studies defining its roles as a tumor promoter, while others characterize its contributions to tumor suppression. These seemingly contradicting roles appear to be due, at least in part, to cell type and temporal mechanisms. Here, we define roles for NLRX1 in regulating critical hallmarks of pancreatic cancer using both gain-of-function and loss-of-function studies in murine Pan02 cells. Our data reveals that NLRX1 increases susceptibility to cell death, while also suppressing proliferation, migration, and reactive oxygen species production. We also show that NLRX1 protects against upregulated mitochondrial activity and limits energy production in the Pan02 cells. Transcriptomics analysis revealed that the protective phenotypes associated with NLRX1 are correlated with attenuation of NF-κB, MAPK, AKT, and inflammasome signaling. Together, these data demonstrate that NLRX1 diminishes cancer-associated biological functions in pancreatic cancer cells and establishes a role for this unique NLR in tumor suppression

    The impact of an employee wellness programme in clothing/textile manufacturing companies: a randomised controlled trial

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    BACKGROUND: The prevalence of health risk behaviours is growing amongst South African employees. Health risk behaviours have been identified as a major contributor to reduced health related quality of life (HRQoL) and the increased prevalence of non-communicable diseases. Worksite wellness programmes promise to promote behaviour changes amongst employees and to improve their HRQoL. The aim of this study was to evaluate the short-term effects of an employee wellness programme on HRQoL, health behaviour change, body mass index (BMI) and absenteeism amongst clothing and textile manufacturing employees. METHODS: The study used a randomised control trial design. The sample consisted of 80 subjects from three clothing manufacturing companies in Cape Town, South Africa. The experimental group was subjected to a wellness programme based on the principles of cognitive behaviour therapy (CBT) as well as weekly supervised exercise classes over six weeks. The control group received a once-off health promotion talk and various educational pamphlets, with no further intervention. Measurements were recorded at baseline and at six weeks post-intervention. Outcome measures included the EQ-5D, Stanford Exercise Behaviours Scale, body mass index and absenteeism.Data was analysed with the Statistica-8 software program. Non-parametric tests were used to evaluate the differences in the medians between the two groups and to determine the level of significance. The Sign test was used to determine the within group changes. The Mann-Whitney U test was used to determine the difference between the two groups. RESULTS: At six weeks post intervention the experimental group (39 subjects) demonstrated improvement in almost every parameter. In contrast, apart from an overall decrease in time off work and a reduction in BMI for all study participants, there was no significant change noted in the behaviour of the control group (41 subjects). Seventy percent of the experimental group had improved HRQoL EQ-5D VAS scores post intervention, indicating improved perceived HRQoL. In comparison, only 58% of the control group had improved HRQoL EQ-5D VAS scores post intervention. There was no significant difference between the two groups at baseline or at six weeks post intervention. CONCLUSION: An employee wellness programme based on the principles of CBT combined with weekly aerobic exercise class was beneficial in improving the perceived HRQoL and changing health-related behaviours of clothing manufacturing employees. However, it cannot be concluded that the EWP was more effective than the once off health promotion talk as no significant changes were noted between the two groups at 6-weeks post intervention.This trial has been registered with ClinicalTrials.gov (trial registration number NCT01625039)

    Immune Activation Reduces Sperm Quality in the Great Tit

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    Mounting an immune response against pathogens incurs costs to organisms by its effects on important life-history traits, such as reproductive investment and survival. As shown recently, immune activation produces large amounts of reactive species and is suggested to induce oxidative stress. Sperm are highly susceptible to oxidative stress, which can negatively impact sperm function and ultimately male fertilizing efficiency. Here we address the question as to whether mounting an immune response affects sperm quality through the damaging effects of oxidative stress. It has been demonstrated recently in birds that carotenoid-based ornaments can be reliable signals of a male's ability to protect sperm from oxidative damage. In a full-factorial design, we immune-challenged great tit males while simultaneously increasing their vitamin E availability, and assessed the effect on sperm quality and oxidative damage. We conducted this experiment in a natural population and tested the males' response to the experimental treatment in relation to their carotenoid-based breast coloration, a condition-dependent trait. Immune activation induced a steeper decline in sperm swimming velocity, thus highlighting the potential costs of an induced immune response on sperm competitive ability and fertilizing efficiency. We found sperm oxidative damage to be negatively correlated with sperm swimming velocity. However, blood resistance to a free-radical attack (a measure of somatic antioxidant capacity) as well as plasma and sperm levels of oxidative damage (lipid peroxidation) remained unaffected, thus suggesting that the observed effect did not arise through oxidative stress. Towards the end of their breeding cycle, swimming velocity of sperm of more intensely colored males was higher, which has important implications for the evolution of mate choice and multiple mating in females because females may accrue both direct and indirect benefits by mating with males having better quality sperm
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