2,650 research outputs found
The self-care for people initiative: the outcome evaluation.
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
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.
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
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
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
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
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
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