354 research outputs found

    Determining the metallicity of the solar envelope using seismic inversion techniques

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    peer reviewedThe solar metallicity issue is a long-lasting problem of astrophysics, impacting multi- ple fields and still subject to debate and uncertainties. While spectroscopy has mostly been used to determine the solar heavy elements abundance, helioseismologists at- tempted providing a seismic determination of the metallicity in the solar convective enveloppe. However, the puzzle remains since two independent groups prodived two radically different values for this crucial astrophysical parameter. We aim at provid- ing an independent seismic measurement of the solar metallicity in the convective enveloppe. Our main goal is to help provide new information to break the current stalemate amongst seismic determinations of the solar heavy element abundance. We start by presenting the kernels, the inversion technique and the target function of the inversion we have developed. We then test our approach in multiple hare-and-hounds exercises to assess its reliability and accuracy. We then apply our technique to solar data using calibrated solar models and determine an interval of seismic measurements for the solar metallicity. We show that our inversion can indeed be used to estimate the solar metallicity thanks to our hare-and-hounds exercises. However, we also show that further dependencies in the physical ingredients of solar models lead to a low accuracy. Nevertheless, using various physical ingredients for our solar models, we determine metallicity values between 0.008 and 0.014

    Systems Simulation Assists Land Capability Estimation in Australia’s Temperate Grasslands

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    Intensification of production in the water-limited grasslands of temperate Australia has increased the need to quantify their sustainable carrying capacity. Empirical rainfall-based rules for estimating stocking rate fail when used in districts with differing weather patterns, or when soil and pasture resources limit the utilisation of rainfall. Grazing systems simulation should help to overcome these problems because local conditions can be taken into account. This study investigated the impact of soil resources on potential stocking rate, profitability and production risk in a local climatic area of the southern tablelands of NSW, Australia

    Electrostatically Directed Self-Assembly of Ultrathin Supramolecular Polymer Microcapsules.

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    Supramolecular self-assembly offers routes to challenging architectures on the molecular and macroscopic scale. Coupled with microfluidics it has been used to make microcapsules-where a 2D sheet is shaped in 3D, encapsulating the volume within. In this paper, a versatile methodology to direct the accumulation of capsule-forming components to the droplet interface using electrostatic interactions is described. In this approach, charged copolymers are selectively partitioned to the microdroplet interface by a complementary charged surfactant for subsequent supramolecular cross-linking via cucurbit[8]uril. This dynamic assembly process is employed to selectively form both hollow, ultrathin microcapsules and solid microparticles from a single solution. The ability to dictate the distribution of a mixture of charged copolymers within the microdroplet, as demonstrated by the single-step fabrication of distinct core-shell microcapsules, gives access to a new generation of innovative self-assembled constructs.This work was supported by the Engineering Physical Sciences Research Council, Institutional Sponsorship 2012-University of Cambridge EP/K503496/1, and the Translational Grant EP/H046593/1; Y.Z. and R.P. were also funded from the Starting Investigator grant ASPiRe (No. 240629) from the European Research Council and the Isaac Newton Trust research grant No. 13.7(c). A.S. was supported by the Nano Doctoral Training Centre (NanoDTC).This is the final version of the article. It first appeared from Wiley at http://dx.doi.org/10.1002/adfm.20150107

    General practitioners' views on reattribution for patients with medically unexplained symptoms: a questionnaire and qualitative study

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    Background: The successful introduction of new methods for managing medically unexplained symptoms in primary care is dependent to a large degree on the attitudes, experiences and expectations of practitioners. As part of an exploratory randomised controlled trial of reattribution training, we sought the views of participating practitioners on patients with medically unexplained symptoms, and on the value of and barriers to the implementation of reattribution in practice. Methods: A nested attitudinal survey and qualitative study in sixteen primary care teams in north-west England. All practitioners participating in the trial (n = 74) were invited to complete a structured survey. Semi-structured interviews were undertaken with a purposive sub-sample of survey respondents, using a structured topic guide. Interview transcripts were used to identify key issues, concepts and themes, which were grouped to construct a conceptual framework: this framework was applied systematically to the data. Results: Seventy (95%) of study participants responded to the survey. Survey respondents often found it stressful to work with patients with medically unexplained symptoms, though those who had received reattribution training were more optimistic about their ability to help them. Interview participants trained in reattribution (n = 12) reported that reattribution increased their confidence to practice in a difficult area, with heightened awareness, altered perceptions of these patients, improved opportunities for team-building and transferable skills. However general practitioners also reported potential barriers to the implementation of reattribution in routine clinical practice, at the level of the patient, the doctor, the consultation, diagnosis and the healthcare context. Conclusion: Reattribution training increases practitioners' sense of competence in managing patients with medically unexplained symptoms. However, barriers to its implementation are considerable, and frequently lie outside the control of a group of practitioners generally sympathetic to patients with medically unexplained symptoms and the purpose of reattribution. These findings add further to the evidence of the difficulty of implementing reattribution in routine general practice

    Reduced Coupling of Oxidative Phosphorylation In Vivo Precedes Electron Transport Chain Defects Due to Mild Oxidative Stress in Mice

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    Oxidative stress and mitochondrial function are at the core of many degenerative conditions. However, the interaction between oxidative stress and in vivo mitochondrial function is unclear. We used both pharmacological (2 week paraquat (PQ) treatment of wild type mice) and transgenic (mice lacking Cu, Zn-superoxide dismutase (SOD1−/−)) models to test the effect of oxidative stress on in vivo mitochondrial function in skeletal muscle. Magnetic resonance and optical spectroscopy were used to measure mitochondrial ATP and oxygen fluxes and cell energetic state. In both models of oxidative stress, coupling of oxidative phosphorylation was significantly lower (lower P/O) at rest in vivo in skeletal muscle and was dose-dependent in the PQ model. Despite this reduction in efficiency, in vivo mitochondrial phosphorylation capacity (ATPmax) was maintained in both models, and ex vivo mitochondrial respiration in permeabilized muscle fibers was unchanged following PQ treatment. In association with the reduced P/O, PQ treatment led to a dose-dependent reduction in PCr/ATP ratio and increased phosphorylation of AMPK. These results indicate that oxidative stress uncouples oxidative phosphorylation in vivo and results in energetic stress in the absence of defects in the mitochondrial electron transport chain

    Subclinical infection and asymptomatic carriage of gastrointestinal zoonoses: Occupational exposure, environmental pathways, and the anonymous spread of disease

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    Asymptomatic carriage of gastrointestinal zoonoses is more common in people whose profession involves them working directly with domesticated animals. Subclinical infections (defined as an infection in which symptoms are either asymptomatic or sufficiently mild to escape diagnosis) are important within a community as unknowing (asymptomatic) carriers of pathogens do not change their behaviour to prevent the spread of disease; therefore the public health significance of asymptomatic human excretion of zoonoses should not be underestimated. However, optimal strategies for managing diseases where asymptomatic carriage instigates further infection remain unresolved, and the impact on disease management is unclear. In this review we consider the environmental pathways associated with prolonged antigenic exposure and critically assess the significance of asymptomatic carriage in disease outbreaks Although screening high-risk groups for occupationally acquired diseases would be logistically problematical, there may be an economic case for identifying and treating asymptomatic carriage if the costs of screening and treatment are less than the costs of identifying and treating those individuals infected by asymptomatic hosts

    Missing the Target for Routine Human Papillomavirus Vaccination: Consistent and Strong Physician Recommendations Are Lacking for 11- to 12-Year-Old Males

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    Rates of routine human papillomavirus (HPV) vaccination of adolescent males in the U.S. are low. Leading health organizations advocate consistent and strong physician recommendations to improve HPV vaccine dissemination. This study describes the prevalence and correlates of consistent and strong physician recommendations for HPV vaccination of adolescent males

    Moving through Motherhood:Involving the Public in Research to Inform Physical Activity Promotion throughout Pregnancy and Beyond

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    open access articleInformation received by women regarding physical activity during and after pregnancy often lacks clarity and may be conflicting and confusing. Without clear, engaging, accessible guidance centred on the experiences of pregnancy and parenting, the benefits of physical activity can be lost. We describe a collaborative process to inform the design of evidence-based, user-centred physical activity resources which reflect diverse experiences of pregnancy and early parenthood. Two iterative, collaborative phases involving patient and public involvement (PPI) workshops, a scoping survey (n = 553) and stakeholder events engaged women and maternity, policy and physical activity stakeholders to inform pilot resource development. These activities shaped understanding of challenges experienced by maternity and physical activity service providers, pregnant women and new mothers in relation to supporting physical activity. Working collaboratively with women and stakeholders, we co-designed pilot resources and identified important considerations for future resource development. Outcomes and lessons learned from this process will inform further work to support physical activity during pregnancy and beyond, but also wider health research where such collaborative approaches are important. We hope that drawing on our experiences and sharing outcomes from this work provide useful information for researchers, healthcare professionals, policy makers and those involved in supporting physical activity behaviour

    Florida physicians' reported use of AFIX-based strategies for human papillomavirus vaccination

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    HPV vaccination rates in Florida are low. To increase rates, the CDC recommends clinics adhere to components of their evidence-based quality improvement program, AFIX (Assessment, Feedback, Incentives, and eXchange of information). We explored factors associated with engaging in HPV-specific AFIX-related activities. In 2016, we conducted a cross-sectional survey of a representative sample of 770 pediatric and family medicine physicians in Florida and assessed vaccination practices, clinic characteristics, and HPV-related knowledge. Data were analyzed in 2017. The primary outcome was whether physicians' clinics engaged in ≥1 AFIX activity. We stratified by physician specialty and developed multivariable models using a backward selection approach. Of the participants in the analytic sample (n = 340), 52% were male, 60% were White of any ethnicity, and 55% were non-Hispanic. Pediatricians and family medicine physicians differed on: years practicing medicine (p < 0.001), HPV-related knowledge (p < 0.001), and VFC provider status (p < 0.001), among others. Only 39% of physicians reported engaging in ≥1 AFIX activity. In the stratified multivariable model for pediatricians, AFIX activity was significantly associated with HPV-related knowledge (aOR = 1.33;95%CI = 1.08–1.63) and provider use of vaccine reminder prompts (aOR = 3.61;95%CI = 1.02–12.77). For family medicine physicians, HPV-related knowledge was significant (aOR = 1.57;95%CI = 1.20–2.05) as was majority race of patient population (non-Hispanic White vs. Other: aOR = 3.02;95%CI = 1.08–8.43), daily patient load (<20 vs. 20–24: aOR = 9.05;95%CI = 2.72–30.10), and vaccine administration to male patients (aOR = 2.98;95%CI = 1.11–8.02). Fewer than half of Florida pediatric and family medicine physicians engaged in any AFIX activities. Future interventions to increase AFIX engagement should focus on implementing and evaluating AFIX activities in groups identified as having low engagement in AFIX activities
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