2,103 research outputs found

    Database Analysis to Support Nutrient Criteria Development (Phase II)

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    The intent of this publication of the Arkansas Water Resources Center is to provide a location whereby a final report on water research to a funding agency can be archived. The Texas Commission on Environmental Quality (TCEQ) contracted with University of Arkansas researchers for a multiple year project titled “Database Analysis to Support Nutrient Criteria Development”. This publication covers the second of three phases of that project and has maintained the original format of the report as submitted to TCEQ. This report can be cited either as an AWRC publication (see below) or directly as the final report to TCEQ

    Proper Motions in the Andromeda Subgroup

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    This article presents results of VLBI observations of regions of H2O maser activity in the Local Group galaxies M33 and IC10. Since all position measurements were made relative to extragalactic background sources, the proper motions of the two galaxies could be measured. For M33, this provides this galaxy's three dimensional velocity, showing that this galaxy is moving with a velocity of 190 +/- 59 km\s relative to the Milky Way. For IC10, we obtain a motion of 215 +/- 42 km/s relative to the Milky Way. These measurements promise a new handle on dynamical models for the Local Group and the mass and dark matter halo of Andromeda and the Milky Way.Comment: 4 pages 1 figures, to appear in the proceedings of "Galaxies in the Local Volume", Astrophysics and Space Science, editors B. Koribalski and H. Jerjen also available at http://www.mpifr-bonn.mpg.de/staff/abrunthaler/pub.shtm

    A kinetic theory of diffusion in general relativity with cosmological scalar field

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    A new model to describe the dynamics of particles undergoing diffusion in general relativity is proposed. The evolution of the particle system is described by a Fokker-Planck equation without friction on the tangent bundle of spacetime. It is shown that the energy-momentum tensor for this matter model is not divergence-free, which makes it inconsistent to couple the Fokker-Planck equation to the Einstein equations. This problem can be solved by postulating the existence of additional matter fields in spacetime or by modifying the Einstein equations. The case of a cosmological scalar field term added to the left hand side of the Einstein equations is studied in some details. For the simplest cosmological model, namely the flat Robertson-Walker spacetime, it is shown that, depending on the initial value of the cosmological scalar field, which can be identified with the present observed value of the cosmological constant, either unlimited expansion or the formation of a singularity in finite time will occur in the future. Future collapse into a singularity also takes place for a suitable small but positive present value of the cosmological constant, in contrast to the standard diffusion-free scenario.Comment: 17 pages, no figures. The present version corrects an erroneous statement on the physical interpretation of the results made in the original publicatio

    The Weak Parity-Violating Pion-Nucleon Coupling (Revised)

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    We use QCD sum rules to obtain the weak parity-violating pion-nucleon coupling constant fπNNf_{\pi NN}. We find that fπNN2×108f_{\pi NN}\approx 2\times 10^{-8}, about an order of magnitude smaller than the ``best estimates'' based on quark models. This result follows from the cancellation between perturbative and nonperturbative QCD processes not found in quark models, but explicit in the QCD sum rule method. Our result is consistent with the experimental upper limit found from 18^{18}F parity-violating measurements.Comment: 13 pages, uses LaTex; figures can be obtained from any of the authors: [email protected], Kisslinger@kelvin. phys.cmu.edu, [email protected]

    Degradation and forgone removals increase the carbon impact of intact forest loss by 626%

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    Intact tropical forests, free from substantial anthropogenic influence, store and sequester large amounts of atmospheric carbon but are currently neglected in international climate policy. We show that between 2000 and 2013, direct clearance of intact tropical forest areas accounted for 3.2% of gross carbon emissions from all deforestation across the pantropics. However, full carbon accounting requires the consideration of forgone carbon sequestration, selective logging, edge effects, and defaunation. When these factors were considered, the net carbon impact resulting from intact tropical forest loss between 2000 and 2013 increased by a factor of 6 (626%), from 0.34 (0.37 to 0.21) to 2.12 (2.85 to 1.00) petagrams of carbon (equivalent to approximately 2 years of global land use change emissions). The climate mitigation value of conserving the 549 million ha of tropical forest that remains intact is therefore significant but will soon dwindle if their rate of loss continues to accelerate

    Understanding patient and family utilisation of community-based palliative care services out-of-hours: Additional analysis of systematic review evidence using narrative synthesis

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    BackgroundCommunity-based out-of-hours services are an integral component of end-of-life care. However, there is little understanding of how patients and families utilise these services. This additional analysis of a systematic review aims to understand and identify patterns of out-of-hours service use and produce recommendations for future service design.MethodData on service use was extracted and secondary analysis undertaken, from a systematic review of models of community out-of-hours services. Narrative synthesis was completed, addressing four specific aspects of service use: 1.Times when patients/families/healthcare professionals need to contact out-of-hours services; 2. Who contacts out-of-hours services; 3. Whether a telephone call, centre visit or home visit is provided; 4. Who responds to out-of-hours calls.ResultsCommunity-based out-of-hours palliative care services were most often accessed between 5pm and midnight, especially on weekdays (with reports of 69% of all calls being made out-of-hours). Family members and carers were the most frequent callers to of the services (making between 60% and 80% of all calls). The type of contact (telephone, centre visit or home visit) varied based on what was offered and on patient need. Over half of services were led by a single discipline (nurse).ConclusionsOut-of-hours services are highly used up to midnight, and particularly by patients’ family and carers. Recommendations to commissioners and service providers are to:• Increase provision of out-of-hours services between 5pm and midnight to reflect the increased use at these times.• Ensure that family and carers are provided with clear contact details for out-of-hours support.• Ensure patient records can be easily accessed by health professionals responding to calls, making the triage process easier.• Listen to patients, family and carers in the design of out-of-hours services, including telephone services.• Collect data systematically on out-of-hours-service use and on outcomes for patients who use the service

    The conceptual models and mechanisms of action that underpin advance care planning for cancer patients: A systematic review of randomised controlled trials

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    Background: No systematic review has focused on conceptual models underpinning advance care planning for patients with advancedcancer, and the mechanisms of action in relation to the intended outcomes.Aim: To appraise conceptual models and develop a logic model of advance care planning for advanced cancer patients, examining thecomponents, processes, theoretical underpinning, mechanisms of action and linkage with intended outcomes.Design: A systematic review of randomised controlled trials was conducted, and was prospectively registered on PROSPERO. Narrativesynthesis was used for data analysis.Data sources: The data sources were MEDLINE, CINAHL, PsycINFO, EMBASE, CENTRAL, PROSPERO, CareSearch, and OpenGreywith reference chaining and hand-searching from inception to 31 March 2017, including all randomised controlled trials withadvance care planning for cancer patients in the last 12 months of life. Cochrane quality assessment tool was used for qualityappraisal.Results: Nine randomised controlled trials were included, with only four articulated conceptual models. Mechanisms through whichadvance care planning improved outcomes comprised (1) increasing patients’ knowledge of end-of-life care, (2) strengtheningpatients’ autonomous motivation, (3) building patients’ competence to undertake end-of-life discussions and (4) enhancing shareddecision-making in a trustful relationship. Samples were largely highly educated Caucasian.Conclusion: The use of conceptual models underpinning the development of advance care planning is uncommon. When used, theyidentify the individual behavioural change. Strengthening patients’ motivation and competence in participating advance care planningdiscussions are key mechanisms of change. Understanding cultural feasibility of the logic model for different educational levels andethnicities in non-Western countries should be a research priority

    On the Truncated Pareto Distribution with applications

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    The Pareto probability distribution is widely applied in different fields such us finance, physics, hydrology, geology and astronomy. This note deals with an application of the Pareto distribution to astrophysics and more precisely to the statistical analysis of mass of stars and of diameters of asteroids. In particular a comparison between the usual Pareto distribution and its truncated version is presented. Finally a possible physical mechanism that produces Pareto tails for the distribution of the masses of stars is suggested.Comment: 10 pages 6 figure
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