1,310 research outputs found

    The treatment of acute bronchitis by general practitioners in the UK - Results of a cross sectional postal survey

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    Copyright © 2002 Royal Australian College of General Practitioners Copyright to Australian Family Physician. Reproduced with permission. Permission to reproduce must be sought from the publisher, The Royal Australian College of General Practitioners.The treatment of acute bronchitis by general practitioners in the UK. Results of a cross sectional postal survey.Nigel P Stocks, Tom Fahe

    Recursive renormalization of the singlet one-pion-exchange plus point-like interactions

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    The subtracted kernel approach is shown to be a powerful method to be implemented recursively in scattering equations with regular plus point-like interactions. The advantages of the method allows one to recursively renormalize the potentials, with higher derivatives of the Dirac-delta, improving previous results. The applicability of the method is verified in the calculation of the 1S0^1S_0 nucleon-nucleon phase-shifts, when considering a potential with one-pion-exchange plus a contact interaction and its derivatives. The 1S0^1S_0 renormalization parameters are fitted to the data. The method can in principle be extended to any derivative order of the contact interaction, to higher partial waves and to coupled channels.Comment: 12 pages, 3 figure

    Renormalization of the one-pion-exchange interaction

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    A renormalization scheme for the nucleon-nucleon (NN) interaction based on a subtracted T-matrix equation is proposed and applied to the one-pion-exchange potential supplemented by contact interactions. The singlet and triplet scattering lengths are given to fix the renormalized strengths of the contact interactions. With only one scaling parameter (μ\mu), the results show an overall very good agreement with neutron-proton data, particularly for the observables related to the triplet channel. The agreement is qualitative in the 1S0^1S_0 channel. Between the low-energy NN observables we have examined, the mixing parameter of the 3S13D1^3S_1-^3D_1 states is the most sensible to the scale. The scheme is renormalization group invariant for μ\mu\to\infty.Comment: 16 pages, 4 eps figures, to appear in Nuclear Physics

    The ecology of seamounts: structure, function, and human impacts.

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    In this review of seamount ecology, we address a number of key scientific issues concerning the structure and function of benthic communities, human impacts, and seamount management and conservation. We consider whether community composition and diversity differ between seamounts and continental slopes, how important dispersal capabilities are in seamount connectivity, what environmental factors drive species composition and diversity, whether seamounts are centers of enhanced biological productivity, and whether they have unique trophic architecture. We discuss how vulnerable seamount communities are to fishing and mining, and how we can balance exploitation of resources and conservation of habitat. Despite considerable advances in recent years, there remain many questions about seamount ecosystems that need closer integration of molecular, oceanographic, and ecological research

    Validation of Geometry Modelling Approaches for Offshore Gas Dispersion Simulations

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    PresentationComputational Fluid Dynamics (CFD) codes are widely used for gas dispersion studies on offshore installations. The majority of these codes use single-block Cartesian grids with the porosity/distributed-resistance (PDR) approach to model small geometric details. Computational cost of this approach is low since small-scale obstacles are not resolved on the computational mesh. However, there are some uncertainties regarding this approach, especially in terms of grid dependency and turbulence generated from complex objects. An alternative approach, which can be implemented in general-purpose CFD codes, is to use body-fitted grids for medium to large- scale objects whilst combining multiple small-scale obstacles in close proximity and using porous media models to represent blockage effects. This approach is validated in this study, by comparing numerical predictions with large-scale gas dispersion experiments carried out in DNV GL’s Spadeadam test site. Gas concentrations and gas cloud volumes obtained from simulations are compared with measurements. These simulations are performed using the commercially available ANSYS CFX, which is a general-purpose CFD code. For comparison, further simulations are performed using CFX where small-scale objects are explicitly resolved. The aim of this work is to evaluate the accuracy and efficiency of these different geometry modelling approaches

    Building research capacity: An exploratory model of GPs' training needs and barriers to research involvement

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    Copyright © 2003 Royal Australian College of General Practitioners Copyright to Australian Family Physician. Reproduced with permission. Permission to reproduce must be sought from the publisher, The Royal Australian College of General Practitioners.AIMS: To determine general practitioners' research training needs, and the barriers to involvement in research. METHOD: Semi-structured interviews with 11 GPs in rural and metropolitan South Australia, analysed using a grounded theory approach. RESULTS: General practitioners' perceptions about their research needs were limited by their own experience and focussed at an individual level. Overlapping needs and barriers emerged, categorised as: 'individual issues' (a lack of research training or experience, concepts and attitudes to research, and research interest) and 'systems issues' (funding arrangements for general practice, access to resources, opportunity for publication and the role of The Royal Australian College of General Practitioners [RACGP]). DISCUSSION: Our data provide an exploratory model that may assist in developing suitable strategies for research capacity building programs. General practitioners perceived both individual and systems solutions to building research capacity, including multifaceted interventions.A. Jones, T.A. Burgess , E.A. Farmer, J. Fuller, N.P. Stocks, J.E. Taylor and R.L. Water

    Validation of geometry modelling approaches for offshore gas dispersion simulations

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    Computational Fluid Dynamics (CFD) codes are widely used for gas dispersion studies on offshore installations. The majority of these codes use single-block Cartesian grids with the porosity/distributed-resistance (PDR) approach to model small geometric details. Computational cost of this approach is low since small-scale obstacles are not resolved on the computational mesh. However, there are some uncertainties regarding this approach, especially in terms of grid dependency and turbulence generated from complex objects. An alternative approach, which can be implemented in general-purpose CFD codes, is to use body-fitted grids for medium to large-scale objects whilst combining multiple small-scale obstacles in close proximity and using porous media models to represent blockage effects. This approach is validated in this study, by comparing numerical predictions with large-scale gas dispersion experiments carried out in DNV GL's Spadeadam test site. Gas concentrations and gas cloud volumes obtained from simulations are compared with measurements. These simulations are performed using the commercially available ANSYS CFX, which is a general-purpose CFD code. For comparison, further simulations are performed using CFX where small-scale objects are explicitly resolved. The aim of this work is to evaluate the accuracy and efficiency of these different geometry modelling approaches

    Antipsychotic prescribing to patients diagnosed with dementia without a diagnosis of psychosis in the context of national guidance and drug safety warnings: longitudinal study in UK general practice

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    Introduction: Policy interventions to address inappropriate prescribing of antipsychotic drugs to older people diagnosed with dementia are commonplace. In the UK, warnings were issued by the Medicines Healthcare products Regulatory Agency in 2004, 2009 and 2012 and the National Institute for Health and Care Excellence guidance was published in 2006. It is important to evaluate the impact of such interventions. Methods: We analysed routinely collected primary-care data from 111,346 patients attending one of 689 general practices contributing to the Clinical Practice Research Datalink to describe the temporal changes in the prescribing of antipsychotic drugs to patients aged 65 years or over diagnosed with dementia without a concomitant psychosis diagnosis from 2001 to 2014 using an interrupted time series and a before-and-after design. Logistic regression methods were used to quantify the impact of patient and practice level variables on prescribing prevalence. Results: Prescribing of first-generation antipsychotic drugs reduced from 8.9% in 2001 to 1.4% in 2014 (prevalence ratio 2014/2001 adjusted for age, sex and clustering within practices (0.14, 95% confidence interval 0.12–0.16), whereas there was little change for second-generation antipsychotic drugs (1.01, confidence interval 0.94–1.17). Between 2004 and 2012, several policy interventions coincided with a pattern of ups and downs, whereas the 2006 National Institute for Health and Care Excellence guidance was followed by a gradual longer term reduction. Since 2013, the decreasing trend in second-generation antipsychotic drug prescribing has plateaued largely driven by the increasing prescribing of risperidone. Conclusions: Increased surveillance and evaluation of drug safety warnings and guidance are needed to improve the impact of future interventions

    Depletion of density of states near Fermi energy induced by disorder and electron correlation in alloys

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    We have performed high resolution photoemission study of substitutionally disordered alloys Cu-Pt, Cu-Pd, Cu-Ni, and Pd-Pt. The ratios between alloy spectra and pure metal spectra are found to have dips at the Fermi level when the residual resistivity is high and when rather strong repulsive electron-electron interaction is expected. This is in accordance with Altshuler and Aronov's model which predicts depletion of density of states at the Fermi level when both disorder and electron correlation are present.Comment: 1 tex file and 4 ps file

    Charge Distributions in Metallic Alloys: a Charge Excess Functional theory approach

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    Charge Distributions in Metallic Alloys: a Charge Excess Functional theory approachComment: 13 pages, 5 figure
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