2,650 research outputs found

    The self-care for people initiative: the outcome evaluation.

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    To determine the effects of a community-based training programme in self-care on the lay population

    Asteroseismic test of rotational mixing in low-mass white dwarfs

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    We exploit the recent discovery of pulsations in mixed-atmosphere (He/H), extremely low-mass white dwarf precursors (ELM proto-WDs) to test the proposition that rotational mixing is a fundamental process in the formation and evolution of low-mass helium core white dwarfs. Rotational mixing has been shown to be a mechanism able to compete efficiently against gravitational settling, thus accounting naturally for the presence of He, as well as traces of metals such as Mg and Ca, typically found in the atmospheres of ELM proto-WDs. Here we investigate whether rotational mixing can maintain a sufficient amount of He in the deeper driving region of the star, such that it can fuel, through HeII-HeIII ionization, the observed pulsations in this type of stars. Using state-of-the-art evolutionary models computed with MESA, we show that rotational mixing can indeed explain qualitatively the very existence and general properties of the known pulsating, mixed-atmosphere ELM proto-WDs. Moreover, such objects are very likely to pulsate again during their final WD cooling phase.Comment: accepted for publication in A&A Letter

    Self-care in primary care: findings from a longitudinal comparison study.

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    To examine the effects of self-care training workshops for primary healthcare workers on frequently attending patients

    Evidence for changes in groundwater drought in temperate environments associated with climate change

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    There is currently a significant gap in our understanding of the effect of anthropogenic warming on groundwater drought. This is due to a number of factors including the limited availability of long groundwater level time series suitable for analysis, the low signal-to-noise ratios characteristic of many hydrological systems, and the infrequent nature of episodes of groundwater drought in temperate systems. Formal attribution of groundwater droughts due to anthropogenic warming is also challenging because of the potentially confounding influences of land use change and groundwater abstraction on groundwater drought. In the present study, we have not attempted to formally attribute groundwater droughts to climate change. Instead, we investigate how known centennialscale anthropogenic warming may be modifying the nature of groundwater droughts when other factors are discounted, and address the following question: how has the occurrence, duration, magnitude and intensity of groundwater drought, as expressed by changes in monthly Standardised Groundwater level Index (SGI) and in episodes of groundwater drought changed since 1891 under anthropogenic warming? Standardised indices of monthly groundwater levels (SGI), precipitation (SPI) and temperature (STI) are analysed, using two long, continuous monthly groundwater level data sets from the UK, for the period 1891 to 2015. Precipitation deficits are the main control on groundwater drought formation and propagation. However, long-term changes in groundwater drought include increases in the frequency and intensity of individual groundwater drought months, and increases in the frequency, magnitude and intensity of episodes of groundwater drought, are shown to be associated with anthropogenic warming over the study period. These is a transition from coincidence of episodes of groundwater and precipitation droughts at the end of the 19th century, to an increasing coincidence groundwater droughts with both precipitation droughts and with hot periods in the early 21st century. In the absence of long-term changes in precipitation deficits, it is inferred that the changing nature of groundwater droughts is due to changes in evapotranspiration (ET) associated with anthropogenic warming. Given the extent of shallow groundwater globally, anthropogenic warming may widely effect changes to groundwater drought characteristics in temperate environments

    Observational properties of massive black hole binary progenitors

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    The first directly detected gravitational waves (GW 150914) were emitted by two coalescing black holes (BHs) with masses of ~36Msun and ~29Msun. Several scenarios have been proposed to put this detection into an astrophysical context. The evolution of an isolated massive binary system is among commonly considered models. Various groups have performed detailed binary-evolution calculations that lead to BH merger events. However, the question remains open as to whether binary systems with the predicted properties really exist. The aim of this paper is to help observers to close this gap by providing spectral characteristics of massive binary BH progenitors during a phase where at least one of the companions is still non-degenerate. Stellar evolution models predict fundamental stellar parameters. Using these as input for our stellar atmosphere code (PoWR), we compute a set of models for selected evolutionary stages of massive merging BH progenitors at different metallicities. The synthetic spectra obtained from our atmosphere calculations reveal that progenitors of massive BH merger events start their lives as O2-3V stars that evolve to early-type blue supergiants before they undergo core-collapse during the Wolf-Rayet phase. When the primary has collapsed, the remaining system will appear as a wind-fed high-mass X-ray binary. We provide feedback parameters, broad band magnitudes, and spectral templates that should help to identify such binaries in the future. Comparisons of empirically determined mass-loss rates with those assumed by evolution calculations reveal significant differences. The consideration of the empirical mass-loss rates in evolution calculations will possibly entail a shift of the maximum in the predicted binary-BH merger rate to higher metallicities, that is, more candidates should be expected in our cosmic neighborhood than previously assumed.Comment: 64 pages, 30 figures, accepted for publication in Astronomy & Astrophysics, v2: typos correcte

    Mapping suitability for open-loop ground source heat pump systems: a screening tool for England and Wales, UK

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    The UK Government expects that, by 2020, 12% of the UK’s heat demand will come from renewable sources, and is providing incentives to help achieve this. Open-loop ground source heat pumps (GSHP) could make a substantial contribution. A web-based screening tool has been developed that highlights areas where conditions may be suitable for installing commercial-scale (>100 kW heating or cooling demand) open-loop GSHP systems in England and Wales. In addition to the basic requirements for open-loop GSHP (i.e. the availability of a sufficiently productive aquifer within a reasonable depth beneath the surface) the tool provides information on existing abstractions, water chemistry and the location of protected areas. Validation and tool application show that it produces reliable results and provides an effective method for the initial assessment of subsurface conditions and suitability for GSHP installations. Hence, the tool can help to reduce uncertainty at the early planning stage, and also to promote GSHP technology to a variety of audiences

    New Candidate Interstellar Particle in Stardust IS Aerogel Collector: Analysis by STXM and Ptychography

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    The Stardust Interstellar Preliminary Examination (ISPE) reported in 2014 the discovery of 7 probable contemporary interstellar (IS) particles captured in Stardust IS Collector aerogel and foils. The ISPE reports represented work done over 6 years by more than 60 scientists and >30,000 volunteers, which emphasizes the challenge identifying and analyzing Stardust IS samples was far beyond the primary Stardust cometary collection. We present a new potentially interstellar particle resulting from a continuation of analyses of the IS aerogel collection

    Magnetohydrodynamic equilibria in barotropic stars

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