1,041 research outputs found

    A thermodynamically self-consistent theory for the Blume-Capel model

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    We use a self-consistent Ornstein-Zernike approximation to study the Blume-Capel ferromagnet on three-dimensional lattices. The correlation functions and the thermodynamics are obtained from the solution of two coupled partial differential equations. The theory provides a comprehensive and accurate description of the phase diagram in all regions, including the wing boundaries in non-zero magnetic field. In particular, the coordinates of the tricritical point are in very good agreement with the best estimates from simulation or series expansion. Numerical and analytical analysis strongly suggest that the theory predicts a universal Ising-like critical behavior along the λ\lambda-line and the wing critical lines, and a tricritical behavior governed by mean-field exponents.Comment: 11 figures. to appear in Physical Review

    The defect challenge of wide-bandgap semiconductors for photovoltaics and beyond

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    The optoelectronic performance of wide-bandgap semiconductors often cannot compete with that of their defect-tolerant small-bandgap counterpart. Here, the authors outline three main challenges to overcome for mitigating the impact of defects in wide-bandgap semiconductors

    Sport-for-development in the South Pacific Region: Macro-, meso-, and micro-perspectives

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    © 2017 Human Kinetics, Inc. As the field of sport-for-development (SFD) has developed, there has been increasing debate over the ability of SFD programs to effect lasting structural change on target communities. Highlighting the barriers to SFD program delivery in five Pacific Island nations, in this paper we argue that numerous challenges emerging at macro-, meso-, and microlevels must be explored, understood, and accounted for to enact structural change. Building on thematic findings from our empirical cross-nation research project, we discuss the importance of addressing SFD challenges at all levels of society to ensure that interventions are appropriately tailored for the specific and often divergent sociocultural contexts in the Pacific Islands region. We argue for a more holistic approach to planning, management, and evaluation when attempting to deliver structural change through sport

    Are they ‘worth their weight in gold’? Sport for older adults: benefits and barriers of their participation for sporting organisations

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    The ageing global population has led to an increased focus on health for older adults. However, older adults have not been a specific priority for some sporting organisations (SOs). Thus, there is an emerging opportunity for this age group to be considered within international sport policy. The aim of this study was to understand the benefits and barriers that SOs encounter when engaging older adults. Eight focus group interviews (n = 49) were held with representatives of Australian national sporting organisations (NSOs), and older adults who were either sport club or non-sport club members. The socioecological model domains, interpersonal, organisational and policy, were used as a framework for thematic analysis, and organisational capacity building concepts were utilised to explain the findings. Common perceived benefits included interpersonal benefits (intergenerational opportunities and role models) and organisational benefits (volunteering, financial contributions and maximised facility usage) for engaging older adults. Common perceived barriers included interpersonal barriers (competing priorities and perceived societal expectations), organisational barriers (lack of appropriate playing opportunities, lack of facility access and lack of club capacity) and policy barriers (strategic organisational focus on children and elite sport and risk management). Whilst participation in sport is not common for older adults, their involvement can be invaluable for sport clubs. It is not anticipated that any policy focus on older adults will significantly increase active participation for this age group. However, any increase in older adults’ sport participation either through actively playing, supporting family and friends and/or volunteering will contribute to the positive health of individuals, sport clubs and the community.Peer reviewedFinal Accepted Versio

    Multi-disciplinary palliative care is effective in people with symptomatic heart failure: A systematic review and narrative synthesis

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    Background: Despite recommendations, people with heart failure have poor access to palliative care. Aim: To identify the evidence in relation to palliative care for people with symptomatic heart failure. Design: Systematic review and narrative synthesis. (PROSPERO CRD42016029911) Data sources: Databases (Medline, Cochrane database, CINAHL, PsycINFO, HMIC, CareSearch Grey Literature), reference lists and citations were searched and experts contacted. Two independent reviewers screened titles and abstracts and retrieved papers against inclusion criteria. Data were extracted from included papers and studies were critically assessed using a risk of bias tool according to design. Results: Thirteen interventional and 10 observational studies were included. Studies were heterogeneous in terms of population, intervention, comparator, outcomes and design rendering combination inappropriate. The evaluation phase studies, with lower risk of bias, using a multi-disciplinary specialist palliative care intervention showed statistically significant benefit for patient-reported outcomes (symptom burden, depression, functional status, quality of life), resource use and costs of care. Benefit was not seen in studies with a single component/discipline intervention or with higher risk of bias. Possible contamination in some studies may have caused under-estimation of effect and missing data may have introduced bias. There was no apparent effect on survival. Conclusion: Overall, the results support the use of multi-disciplinary palliative care in people with advanced heart failure but trials do not identify who would benefit most from specialist palliative referral. There are no sufficiently robust multi-centre evaluation phase trials to provide generalisable findings. Use of common population, intervention and outcomes in future research would allow meta-analysis

    Understanding the role of grain boundaries on charge-carrier and ion transport in Cs2AgBiBr6 thin films

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    Halide double perovskites have gained significant attention, owing to their composition of low-toxicity elements, stability in air, and recent demonstrations of long charge-carrier lifetimes that can exceed 1 s. In particular, Cs2AgBiBr6 has been the subject of many investigations in photovoltaic devices. However, the efficiencies of solar cells based on this double perovskite are still far from the theoretical efficiency limit of the material. Here, we investigate the role of grain size on the optoelectronic properties of Cs2AgBiBr6 thin films. We show through cathodoluminescence measurements that grain boundaries are the dominant non-radiative recombination sites. We also demonstrate through field-effect transistor and temperature-dependent transient current measurements that grain boundaries act as the main channels for ion transport. Interestingly, we find a positive correlation between carrier mobility and temperature, which resembles the hopping mechanism often seen in organic semiconductors. These findings explain the discrepancy between the long diffusion lengths >1 m found in Cs2AgBiBr6 single crystals versus the limited performance achieved in their thin film counterparts. Our work shows that mitigating the impact of grain boundaries will be critical for these double perovskite thin films to reach the performance achievable based on their intrinsic single-crystal properties

    MicroRNA profiling reveals marker of motor neuron disease in ALS models

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    Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder marked by the loss of motor neurons (MNs) in the brain and spinal cord, leading to fatally debilitating weakness. Because this disease predominantly affects MNs, we aimed to characterize the distinct expression profile of that cell type to elucidate underlying disease mechanisms and to identify novel targets that inform on MN health during ALS disease time course. microRNAs (miRNAs) are short, noncoding RNAs that can shape the expression profile of a cell and thus often exhibit cell-type-enriched expression. To determine MN-enriched miRNA expression, we used Cre recombinase-dependent miRNA tagging and affinity purification in mice. By defining thein vivomiRNA expression of MNs, all neurons, astrocytes, and microglia, we then focused on MN-enriched miRNAs via a comparative analysis and found that they may functionally distinguish MNs postnatally from other spinal neurons. Characterizing the levels of the MN-enriched miRNAs in CSF harvested from ALS models of MN disease demonstrated that one miRNA (miR-218) tracked with MN loss and was responsive to an ALS therapy in rodent models. Therefore, we have used cellular expression profiling tools to define the distinct miRNA expression of MNs, which is likely to enrich future studies of MN disease. This approach enabled the development of a novel, drug-responsive marker of MN disease in ALS rodents.SIGNIFICANCE STATEMENTAmyotrophic lateral sclerosis (ALS) is a neurodegenerative disease in which motor neurons (MNs) in the brain and spinal cord are selectively lost. To develop tools to aid in our understanding of the distinct expression profiles of MNs and, ultimately, to monitor MN disease progression, we identified small regulatory microRNAs (miRNAs) that were highly enriched or exclusive in MNs. The signal for one of these MN-enriched miRNAs is detectable in spinal tap biofluid from an ALS rat model, where its levels change as disease progresses, suggesting that it may be a clinically useful marker of disease status. Furthermore, rats treated with ALS therapy have restored expression of this MN RNA marker, making it an MN-specific and drug-responsive marker for ALS rodents.</jats:p

    The active living gender's gap challenge: 2013-2017 Eurobarometers physical inactivity data show constant higher prevalence in women with no progress towards global reduction goals

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    BACKGROUND: The World Health Organization (WHO) considers physical inactivity (PIA) as a critical noncommunicable factor for disease and mortality, affecting more women than men. In 2013, the WHO set a 10% reduction of the PIA prevalence, with the goal to be reached by 2025. Changes in the 2013-2017 period of physical inactivity prevalence in the 28 European Union (EU) countries were evaluated to track the progress in achieving WHO 2025 target. METHODS: In 2013 and 2017 EU Special Eurobarometers, the physical activity levels reported by the International Physical Activity Questionnaire of 53,607 adults were analyzed. Data were considered as a whole sample and country-by-country. A χ2 test was used to analyze the physical inactivity prevalence (%) between countries, analyzing women and men together and separately. Additionally, PIA prevalence was analyzed between years (2013-2017) for the overall EU sample and within-country using a Z-Score for two population proportions. RESULTS: The PIA prevalence increased between 2013 and 2017 for the overall EU sample (p <  0.001), and for women (p = 0.04) and men (p < 0.001) separately. Data showed a higher PIA prevalence in women versus men during both years (p <  0.001). When separately considering changes in PIA by gender, only Belgium's women and Luxembourg's men showed a reduction in PIA prevalence. Increases in PIA prevalence over time were observed in women from Austria, Croatia, Germany, Lithuania, Malta, Portugal, Romania, and Slovakia and in men from Bulgaria, Croatia, Czechia, Germany, Italy, Lithuania, Portugal, Romania, Slovakia, and Spain. CONCLUSIONS: PIA prevalence showed an overall increase across the EU and for both women and men between 2013 and 2017, with higher rates of PIA reported for women versus men during both years. PIA prevalence was reduced in only Belgium's women and Luxembourg's men. Our data indicate a limited gender-sensible approach while tacking PIA prevalence with no progress reaching global voluntary reductions of PIA for 2025
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