1,950 research outputs found

    Influence of impurity spin dynamics on quantum transport in epitaxial graphene

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    Experimental evidence from both spin-valve and quantum transport measurements points towards unexpectedly fast spin relaxation in graphene. We report magnetotransport studies of epitaxial graphene on SiC in a vector magnetic field showing that spin relaxation, detected using weak-localisation analysis, is suppressed by an in-plane magnetic field, B∥B_{\parallel}, and thereby proving that it is caused at least in part by spinful scatterers. A non-monotonic dependence of effective decoherence rate on B∥B_{\parallel} reveals the intricate role of scatterers' spin dynamics in forming the interference correction to conductivity, an effect that has gone unnoticed in earlier weak localisation studie

    Encoded and updated spatial working memories share a common representational format in alpha activity

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    Working memory (WM) flexibly updates information to adapt to the dynamic environment. Here, we used alpha-band activity in the EEG to reconstruct the content of dynamic WM updates and compared this representational format to static WM content. An inverted encoding model using alpha activity precisely tracked both the initially encoded position and the updated position following an auditory cue signaling mental updating. The timing of the update, as tracked in the EEG, correlated with reaction times and saccade latency. Finally, cross-training analyses revealed a robust generalization of alpha-band reconstruction of WM contents before and after updating. These findings demonstrate that alpha activity tracks the dynamic updates to spatial WM and that the format of this activity is preserved across the encoded and updated representations. Thus, our results highlight a new approach for measuring updates to WM and show common representational formats during dynamic mental updating and static storage

    Genome -Scale Reconstruction of Metabolic Networks of Lactobacillus casei ATCC 334 and 12A

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    Lactobacillus casei strains are widely used in industry and the utility of this organism in these industrial applications is straindependent. Hence, tools capable of predicting strain specific phenotypes would have utility in the selection of strains forspecific industrial processes. Genome-scale metabolic models can be utilized to better understand genotype-phenotyperelationships and to compare different organisms. To assist in the selection and development of strains with enhancedindustrial utility, genome-scale models for L. casei ATCC 334, a well characterized strain, and strain 12A, a corn silage isolate,were constructed. Draft models were generated from RAST genome annotations using the Model SEED database and refined by evaluating ATP generating cycles, mass-and-charge-balances of reactions, and growth phenotypes. After the validation process was finished, we compared the metabolic networks of these two strains to identify metabolic, genetic and ortholog differences that may lead to different phenotypic behaviors. We conclude that the metabolic capabilities of the two networks are highly similar. The L. casei ATCC 334 model accounts for 1,040 reactions, 959 metabolites and 548 genes, while the L. casei 12A model accounts for 1,076 reactions, 979 metabolites and 640 genes. The developed L. casei ATCC 334 and 12A metabolic models will enable better understanding of the physiology of these organisms and be valuable tools in the development and selection of strains with enhanced utility in a variety of industrial applications

    Automated Reminders to Promote Radon Testing in a Lung Cancer Case Control Study

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    One of the four pilot projects of the Lung Cancer Initiative sponsored by the Department of Defense measures radon levels in the participants homes. Radon exposure is the second leading cause of Lung Cancer. The case-control study has a targeted accrual of 1800 with a case-control ratio of 1:4. The long-term radon kits remain in the home for 90 days and the participants are asked to mail the test kit to the company for analysis. In order to maximize the test kit return rate, reminder calls to the participants occurred 90 days after the home visit

    Preparing for and managing change: Climate adaptation for biodiversity and ecosystems

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    The emerging field of climate-change adaptation has experienced a dramatic increase in attention as the impacts of climate change on biodiversity and ecosystems have become more evident. Preparing for and addressing these changes are now prominent themes in conservation and natural resource policy and practice. Adaptation increasingly is viewed as a way of managing change, rather than just maintaining existing conditions. There is also increasing recognition of the need not only to adjust management strategies in light of climate shifts, but to reassess and, as needed, modify underlying conservation goals. Major advances in the development of climate-adaptation principles, strategies, and planning processes have occurred over the past few years, although implementation of adaptation plans continues to lag. With ecosystems expected to undergo continuing climate-mediated changes for years to come, adaptation can best be thought of as an ongoing process, rather than as a fixed endpoint. © The Ecological Society of America

    Strengthening health human resources and improving clinical outcomes through an integrated guideline and educational outreach in resource-poor settings: a cluster-randomized trial

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    <p>Abstract</p> <p>Background</p> <p>In low-income countries, only about a third of Human Immunodeficiency Virus/Acquired Immune Deficiency Syndrome (HIV/AIDS) patients eligible for anti-retroviral treatment currently receive it. Providing decentralized treatment close to where patients live is crucial to a faster scale up, however, a key obstacle is limited health system capacity due to a shortage of trained health-care workers and challenges of integrating HIV/AIDS care with other primary care services (e.g. tuberculosis, malaria, respiratory conditions). This study will test an adapted primary care health care worker training and guideline intervention, Practical Approach to Lung Health and HIV/AIDS Malawi (PALM PLUS), on staff retention and satisfaction, and quality of patient care.</p> <p>Methods/Design</p> <p>A cluster-randomized trial design is being used to compare usual care with a standardized clinical guideline and training intervention, PALM PLUS. The intervention targets middle-cadre health care workers (nurses, clinical officers, medical assistants) in 30 rural primary care health centres in a single district in Malawi. PALM PLUS is an integrated, symptom-based and user-friendly guideline consistent with Malawian national treatment protocols. Training is standardized and based on an educational outreach approach. Trainers will be front-line peer healthcare workers trained to provide outreach training and support to their fellow front-line healthcare workers during focused (1-2 hours), intermittent, interactive sessions on-site in health centers. Primary outcomes are health care worker retention and satisfaction. Secondary outcomes are clinical outcomes measured at the health centre level for HIV/AIDS, tuberculosis, prevention-of-mother-to-child-transmission of HIV and other primary care conditions. Effect sizes and 95% confidence intervals for outcomes will be presented. Assessment of outcomes will occur at 1 year post- implementation.</p> <p>Discussion</p> <p>The PALM PLUS trial aims to address a key problem: strengthening middle-cadre health care workers to support the broader scale up of HIV/AIDS services and their integration into primary care. The trial will test whether the PALM PLUS intervention improves staff satisfaction and retention, as well as the quality of patient care, when compared to usual practice.</p> <p>Trial Registration</p> <p>Current controlled Trials: <a href="http://www.controlled-trials.com/ISRCTN47805230">ISRCTN47805230</a></p

    BUB-1 targets PP2A:B56 to regulate chromosome congression during meiosis I in C. elegans oocytes

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    Protein Phosphatase 2A (PP2A) is a heterotrimer composed of scaffolding (A), catalytic (C), and regulatory (B) subunits. PP2A complexes with B56 subunits are targeted by Shugoshin and BUBR1 to protect centromeric cohesion and stabilise kinetochore-microtubule attachments in yeast and mouse meiosis. In Caenorhabditis elegans, the closest BUBR1 orthologue lacks the B56-interaction domain and Shugoshin is not required for meiotic segregation. Therefore, the role of PP2A in C. elegans female meiosis is unknown. We report that PP2A is essential for meiotic spindle assembly and chromosome dynamics during C. elegans female meiosis. BUB-1 is the main chromosome-targeting factor for B56 subunits during prometaphase I. BUB-1 recruits PP2A:B56 to the chromosomes via a newly identified LxxIxE motif in a phosphorylation-dependent manner, and this recruitment is important for proper chromosome congression. Our results highlight a novel mechanism for B56 recruitment, essential for recruiting a pool of PP2A involved in chromosome congression during meiosis I

    Evaluating a streamlined clinical tool and educational outreach intervention for health care workers in Malawi: the PALM PLUS case study

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    <p>Abstract</p> <p>Background</p> <p>Nearly 3 million people in resource-poor countries receive antiretrovirals for the treatment of HIV/AIDS, yet millions more require treatment. Key barriers to treatment scale up are shortages of trained health care workers, and challenges integrating HIV/AIDS care with primary care.</p> <p>The research</p> <p>PALM PLUS (Practical Approach to Lung Health and HIV/AIDS in Malawi) is an intervention designed to simplify and integrate existing Malawian national guidelines into a single, simple, user-friendly guideline for mid-level health care workers. Training utilizes a peer-to-peer educational outreach approach. Research is being undertaken to evaluate this intervention to generate evidence that will guide future decision-making for consideration of roll out in Malawi. The research consists of a cluster randomized trial in 30 public health centres in Zomba District that measures the effect of the intervention on staff satisfaction and retention, quality of patient care, and costs through quantitative, qualitative and health economics methods.</p> <p>Results and outcomes</p> <p>In the first phase of qualitative inquiry respondents from intervention sites demonstrated in-depth knowledge of PALM PLUS compared to those from control sites. Participants in intervention sites felt that the PALM PLUS tool empowered them to provide better health services to patients. Interim staff retention data shows that there were, on average, 3 to 4 staff departing from the control and intervention sites per month. Additional qualitative, quantitative and economic analyses are planned.</p> <p>The partnership</p> <p>Dignitas International and the Knowledge Translation Unit at the University of Cape Town Lung Institute have led the adaptation and development of the PALM PLUS intervention, using experience gained through the implementation of the South African precursor, PALSA PLUS. The Malawian partners, REACH Trust and the Research Unit at the Ministry of Health, have led the qualitative and economic evaluations. Dignitas and Ministry of Health have facilitated interaction with implementers and policy-makers.</p> <p>Challenges and successes</p> <p>This initiative is an example of South-South knowledge translation between South Africa and Malawi, mediated by a Canadian academic-NGO hybrid. Our success in developing and rolling out PALM PLUS in Malawi suggests that it is possible to adapt and implement this intervention for use in other resource-limited settings.</p

    Genome-wide Association of Lipid-lowering Response to Statins in Combined Study Populations

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    Background: Statins effectively lower total and plasma LDL-cholesterol, but the magnitude of decrease varies among individuals. To identify single nucleotide polymorphisms (SNPs) contributing to this variation, we performed a combined analysis of genome-wide association (GWA) results from three trials of statin efficacy. Methods and Principal Findings: Bayesian and standard frequentist association analyses were performed on untreated and statin-mediated changes in LDL-cholesterol, total cholesterol, HDL-cholesterol, and triglyceride on a total of 3932 subjects using data from three studies: Cholesterol and Pharmacogenetics (40 mg/day simvastatin, 6 weeks), Pravastatin/Inflammation CRP Evaluation (40 mg/day pravastatin, 24 weeks), and Treating to New Targets (10 mg/day atorvastatin, 8 weeks). Genotype imputation was used to maximize genomic coverage and to combine information across studies. Phenotypes were normalized within each study to account for systematic differences among studies, and fixed-effects combined analysis of the combined sample were performed to detect consistent effects across studies. Two SNP associations were assessed as having posterior probability greater than 50%, indicating that they were more likely than not to be genuinely associated with statin-mediated lipid response. SNP rs8014194, located within the CLMN gene on chromosome 14, was strongly associated with statin-mediated change in total cholesterol with an 84% probability by Bayesian analysis, and a p-value exceeding conventional levels of genome-wide significance by frequentist analysis (P = 1.8×10−8^{−8}). This SNP was less significantly associated with change in LDL-cholesterol (posterior probability = 0.16, P = 4.0×10−6^{−6}). Bayesian analysis also assigned a 51% probability that rs4420638, located in APOC1 and near APOE, was associated with change in LDL-cholesterol. Conclusions and Significance: Using combined GWA analysis from three clinical trials involving nearly 4,000 individuals treated with simvastatin, pravastatin, or atorvastatin, we have identified SNPs that may be associated with variation in the magnitude of statin-mediated reduction in total and LDL-cholesterol, including one in the CLMN gene for which statistical evidence for association exceeds conventional levels of genome-wide significance.Trial Registration PRINCE and TNT are not registered. CAP is registered at Clinicaltrials.gov NCT0045182
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