5,490 research outputs found

    Time to publication for NIHR HTA programme-funded research: a cohort study

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    ObjectiveTo assess the time to publication of primary research and evidence syntheses funded by the National Institute for Health Research (NIHR) Health Technology Assessment (HTA) Programme published as a monograph in Health Technology Assessment and as a journal article in the wider biomedical literature.Study designRetrospective cohort study.SettingPrimary research and evidence synthesis projects funded by the HTA Programme were included in the cohort if they were registered in the NIHR research programmes database and was planned to submit the draft final report for publication in Health Technology Assessment on or before 9 December 2011.Main outcome measuresThe median time to publication and publication at 30?months in Health Technology Assessment and in an external journal were determined by searching the NIHR research programmes database and HTA Programme website.ResultsOf 458 included projects, 184 (40.2%) were primary research projects and 274 (59.8%) were evidence syntheses. A total of 155 primary research projects had a completion date; the median time to publication was 23?months (26.5 and 35.5?months to publish a monograph and to publish in an external journal, respectively) and 69% were published within 30?months. The median time to publication of HTA-funded trials (n=126) was 24?months and 67.5% were published within 30?months. Among the evidence syntheses with a protocol online date (n=223), the median time to publication was 25.5?months (28?months to publication as a monograph), but only 44.4% of evidence synthesis projects were published in an external journal. 65% of evidence synthesis studies had been published within 30.0?months.ConclusionsResearch funded by the HTA Programme publishes promptly. The importance of Health Technology Assessment was highlighted as the median time to publication was 9?months shorter for a monograph than an external journal article

    Quantum steering ellipsoids, extremal physical states and monogamy

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    A Corrigendum for this article has been published in 2015 New J. Phys. 17 019501Any two-qubit state can be faithfully represented by a steering ellipsoid inside the Bloch sphere, but not every ellipsoid inside the Bloch sphere corresponds to a two-qubit state. We give necessary and sufficient conditions for when the geometric data describe a physical state and investigate maximal volume ellipsoids lying on the physical-unphysical boundary. We derive monogamy relations for steering that are strictly stronger than the Coffman-Kundu- Wootters (CKW) inequality for monogamy of concurrence. The CKW result is thus found to follow from the simple perspective of steering ellipsoid geometry. Remarkably, we can also use steering ellipsoids to derive non-trivial results in classical Euclidean geometry, extending Eulers inequality for the circumradius and inradius of a triangle.The EPSRC and the ARC Centre of Excellence grant no. CE110001027. DJ is funded by the Royal Society. TR would like to thank the Leverhulme Trust. SJ acknowledges EPSRC grant EP/ K022512/1

    Hypertension Guideline 2003 Update

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    Outcomes. Extensive data from many randomised controlled trials have shown the benefit of treating hypertension. The target blood pressure (BP) for antihypertensive management should be systolic BP < 140 mmHg, diastolic < 90 mmHg, with minimal or no drug side-effects. However, a lesser reduction will elicit benefit although this is not optimal. The reduction of BP in the elderly and in those with severe hypertension should be achieved gradually over 6 months. Stricter BP control is required for patients with end organ damage, co-existing risk factors and co-morbidity, e.g. diabetes mellitus. Co-existent risk factors should also be controlled.Benefits. Reduction in risk of stroke, cardiac failure, renal insufficiency and probably coronary artery disease. The major precautions and contraindications to each antihypertensive drug recommended are listed.Recommendations. Correct BP measurement procedure is described. Evaluation of cardiovascular risk factors and recommendations for antihypertensive therapy are stipulated. The total cardiovascular disease risk profile should be determined for all patients and this should inform management strategies. 'Lifestyle modification and patient education plays an essential role in the management strategy. Drug therapy: First line -low dose thiazide-like diuretics; second line -add one of the following: reserpine or ÎČ-blockers or ACE inhibitors or calcium channel blockers; third line - add another second line drug or hydralazine or α-blocker. The guideline includes management of specific situations, i.e. hypertensive emergency and urgency, severe hypertension with target organ damage and refractory hypertension (BP >160/95 mmHg on triple therapy), hypertension in diabetes mellitus, etc.Validity. Developed by the Working Groups established by the Executive Committee of the Southern African Hypertension Society with broader consensus meeting endorsement. The 2001 version was endorsed by the South African Medical Association Guideline Committee. The 2003 revisions were endorsed by the Executive Committee and a wider Working Group

    Naive Bayesian Learning in 2 x 2 Matrix Games

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    Evidence of a Curved Synchrotron Spectrum in the Supernova Remnant SN 1006

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    A joint spectral analysis of some Chandra ACIS X-ray data and Molonglo Observatory Synthesis Telescope radio data was performed for 13 small regions along the bright northeastern rim of the supernova remnant SN 1006. These data were fitted with a synchrotron radiation model. The nonthermal electron spectrum used to compute the photon emission spectra is the traditional exponentially cut off power law, with one notable difference: The power-law index is not a constant. It is a linear function of the logarithm of the momentum. This functional form enables us to show, for the first time, that the synchrotron spectrum of SN 1006 seems to flatten with increasing energy. The effective power-law index of the electron spectrum is 2.2 at 1 GeV (i.e., radio synchrotron-emitting momenta) and 2.0 at about 10 TeV (i.e., X-ray synchrotron-emitting momenta). This amount of change in the index is qualitatively consistent with theoretical models of the amount of curvature in the proton spectrum of the remnant. The evidence of spectral curvature implies that cosmic rays are dynamically important instead of being "test" particles. The spectral analysis also provides a means of determining the critical frequency of the synchrotron spectrum associated with the highest-energy electrons. The critical frequency seems to vary along the northeastern rim, with a maximum value of 1.1e17 (0.6e17 - 2.1e17) Hz. This value implies that the electron diffusion coefficient can be no larger than a factor of ~4.5-21 times the Bohm diffusion coefficient if the velocity of the forward shock is in the range 2300-5000 km/s. Since the coefficient is close to the Bohm limit, electrons are accelerated nearly as fast as possible in the regions where the critical frequency is about 1.0e17 Hz.Comment: 41 pages, 8 figures, accepted by Ap

    On Albanese torsors and the elementary obstruction

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    We show that the elementary obstruction to the existence of 0-cycles of degree 1 on an arbitrary variety X (over an arbitrary field) can be expressed in terms of the Albanese 1-motives associated with dense open subsets of X. Arithmetic applications are given

    Chabauty-Coleman experiments for genus 3 hyperelliptic curves

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    We describe a computation of rational points on genus 3 hyperelliptic curves CC defined over Q\mathbb{Q} whose Jacobians have Mordell-Weil rank 1. Using the method of Chabauty and Coleman, we present and implement an algorithm in Sage to compute the zero locus of two Coleman integrals and analyze the finite set of points cut out by the vanishing of these integrals. We run the algorithm on approximately 17,000 curves from a forthcoming database of genus 3 hyperelliptic curves and discuss some interesting examples where the zero set includes global points not found in C(Q)C(\mathbb{Q}).Comment: 18 page

    An analysis of the X-ray emission from the supernova remnant 3C397

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    The ASCA SIS and the ROSAT PSPC spectral data of the SNR 3C397 are analysed with a two-component non-equilibrium ionization model. Besides, the ASCA SIS0 and SIS1 spectra are also fitted simultaneously in an equilibrium case. The resulting values of the hydrogen column density yield a distance of \sim8\kpc to 3C397. It is found that the hard X-ray emission, containing S and Fe Kα\alpha lines, arises primarily from the hot component, while most of the soft emission, composed mainly of Mg, Si, Fe L lines, and continuum, is produced by the cool component. The emission measures suggest that the remnant evolves in a cloudy medium and imply that the supernova progenitor might not be a massive early-type star. The cool component is approaching ionization equilibrium. The ages estimated from the ionization parameters and dynamics are all much greater than the previous determination. We restore the X-ray maps using the ASCA SIS data and compare them with the ROSAT HRI and the NRAO VLA Sky Survey (NVSS) 20 cm maps. The morphology with two bright concentrations suggests a bipolar remnant encountering a denser medium in the west.Comment: 20 pages, aasms4.sty, 3 figures To appear in ApJ (1999

    Using Functional Traits to Model Annual Plant Community Dynamics

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    Predicting the response of biological communities to changes in the environment or management is a fundamental pursuit of community ecology. Meeting this challenge requires the integration of multiple processes: habitat filtering, niche differentiation, biotic interactions, competitive exclusion, and stochastic demographic events. Most approaches to this long-standing problem focus either on the role of the environment, using trait-based filtering approaches, or on quantifying biotic interactions with process-based community dynamics models. We introduce a novel approach that uses functional traits to parametrise a process-based model. By combining the two approaches we make use of the extensive literature on traits and community filtering as a convenient means of reducing the parametrisation requirements of a complex population dynamics model whilst retaining the power to capture the processes underlying community assembly. Using arable weed communities as a case study, we demonstrate that this approach results in predictions that show realistic distributions of traits and that trait selection predicted by our simulations is consistent with in-field observations. We demonstrate that trait-based filtering approaches can be combined with process-based models to derive the emergent distribution of traits. While initially developed to predict the impact of crop management on functional shifts in weed communities, our approach has the potential to be applied to other annual plant communities if the generality of relationships between traits and model parameters can be confirmed
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