7,806 research outputs found
Care staff perspectives of the role of music in the care of peopleliving with dementia
The rationale for this study was grounded in the current emphasis on developing non-pharmacological interventions for people living with dementia in the UK. The study investigated the common practice amongst care staff caring for people living with dementia to commission music activities as a recreational pastime. It examined staff perspectives on the value of these activities and the potential to develop the scope of therapeutic benefits that might simultaneously support the well-being of both the cared-for and the care-giver. It investigated personal and professional factors that might underpin inhibitions to staff training to facilitate music activities themselves and to staff exploring music as an education tool to develop creative and reflective practice. The study sought to generate original findings and to contribute to an evidence base to inform future practice.
Method triangulation involved a questionnaire survey, telephone and face-to-face interviews, focus group discussions and participant observations. One hundred and ninety two participants took part in the study, comprising 149 care staff and 13 music practitioners who collectively worked in one or more of 27 care settings for older people in east Kent, 27 older people and three informal carers. The results showed that musicians and music practitioners were typically engaged by staff to deliver a fairly similar range of activities, around ten times per year on average. Practical barriers to staff taking part in these activities centred on issues of time-tabling and the challenges of balancing routine care-giving with non-routine activities. Psychological barriers appeared to be influenced by: cultural backgrounds; staff experiences of music education at school; preconceptions about musical skill; personal levels of confidence; social pressures; inter-staff relationships; and the relationships that staff have with visiting musicians. Barriers to formal training for staff to explore music as a catalyst for creative and reflective practice also included low or non-prioritisation of music in relation to their care-giving role and a belief that only musical staff would benefit
Application of Pade Approximants to Determination of alpha_s(M_Z^2) from Hadronic Event Shape Observables in e+e- Annihilation
We have applied Pade approximants to perturbative QCD calculations of event
shape observables in e+e- --> hadrons. We used the exact O(alpha_s^2)
prediction and the [0/1] Pade approximant to estimate the O(alpha_s^3) term for
15 observables, and in each case determined alpha_s(M_Z^2) from comparison with
hadronic Z^0 decay data from the SLD experiment. We found the scatter among the
alpha_s(M_Z^2) values to be significantly reduced compared with the standard
O(alpha_s^2) determination, implying that the Pade method provides at least a
partial approximation of higher-order perturbative contributions to event shape
observables.Comment: 15 pages, 1 EPS figure, Submitted to Physics Letters
Criteria for Core-Collapse Supernova Explosions by the Neutrino Mechanism
We investigate the criteria for successful core-collapse supernova explosions
by the neutrino mechanism. We find that a
critical-luminosity/mass-accretion-rate condition distinguishes non-exploding
from exploding models in hydrodynamic one-dimensional (1D) and two-dimensional
(2D) simulations. We present 95 such simulations that parametrically explore
the dependence on neutrino luminosity, mass accretion rate, resolution, and
dimensionality. While radial oscillations mediate the transition between 1D
accretion (non-exploding) and exploding simulations, the non-radial standing
accretion shock instability characterizes 2D simulations. We find that it is
useful to compare the average dwell time of matter in the gain region with the
corresponding heating timescale, but that tracking the residence time
distribution function of tracer particles better describes the complex flows in
multi-dimensional simulations. Integral quantities such as the net heating
rate, heating efficiency, and mass in the gain region decrease with time in
non-exploding models, but for 2D exploding models, increase before, during, and
after explosion. At the onset of explosion in 2D, the heating efficiency is
2% to 5% and the mass in the gain region is 0.005 M_{\sun}
to 0.01 M_{\sun}. Importantly, we find that the critical luminosity for
explosions in 2D is 70% of the critical luminosity required in 1D. This
result is not sensitive to resolution or whether the 2D computational domain is
a quadrant or the full 180. We suggest that the relaxation of the
explosion condition in going from 1D to 2D (and to, perhaps, 3D) is of a
general character and is not limited by the parametric nature of this study.Comment: 32 pages in emulateapj, including 17 figures, accepted for
publication in ApJ, included changes suggested by the refere
Gravitational Wave Background from Neutrino-Driven Gamma-Ray Bursts
We discuss the gravitational wave background (GWB) from a cosmological
population of gamma-ray bursts (GRBs). Among various emission mechanisms for
the gravitational waves (GWs), we pay a particular attention to the vast
anisotropic neutrino emissions from the accretion disk around the black hole
formed after the so-called failed supernova explosions. The produced GWs by
such mechanism are known as burst with memory, which could dominate over the
low-frequency regime below \sim 10Hz. To estimate their amplitudes, we derive
general analytic formulae for gravitational waveform from the axisymmetric
jets. Based on the formulae, we first quantify the spectrum of GWs from a
single GRB. Then, summing up its cosmological population, we find that the
resultant value of the density parameter becomes roughly \Omega_{GW} \approx
10^{-20} over the wide-band of the low-frequency region, f\sim 10^{-4}-10^1Hz.
The amplitude of GWB is sufficiently smaller than the primordial GWBs
originated from an inflationary epoch and far below the detection limit.Comment: 6 pages, 4 figures, accepted for publication in MNRA
A simple toy model of the advective-acoustic instability I. Perturbative approach
Some general properties of the advective-acoustic instability are described
and understood using a toy model which is simple enough to allow for analytical
estimates of the eigenfrequencies. The essential ingredients of this model, in
the unperturbed regime, are a stationary shock and a subsonic region of
deceleration. For the sake of analytical simplicity, the 2D unperturbed flow is
parallel and the deceleration is produced adiabatically by an external
potential. The instability mechanism is determined unambiguously as the
consequence of a cycle between advected and acoustic perturbations. The purely
acoustic cycle, considered alone, is proven to be stable in this flow. Its
contribution to the instability can be either constructive or destructive. A
frequency cut-off is associated to the advection time through the region of
deceleration. This cut-off frequency explains why the instability favours
eigenmodes with a low frequency and a large horizontal wavelength. The relation
between the instability occurring in this highly simplified toy model and the
properties of SASI observed in the numerical simulations of stellar
core-collapse is discussed. This simple set up is proposed as a benchmark test
to evaluate the accuracy, in the linear regime, of numerical simulations
involving this instability. We illustrate such benchmark simulations in a
companion paper.Comment: 14 pages, 10 figures, ApJ in pres
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Evolutionarily stable sexual allocation by both stressed and unstressed potentially simultaneous hermaphrodites within the same population.
Factors influencing allocation of resources to male and female offspring continue to be of great interest to evolutionary biologists. A simultaneous hermaphrodite is capable of functioning in both male and female mode at the same time, and such a life-history strategy is adopted by most flowering plants and by many sessile aquatic animals. In this paper, we focus on hermaphrodites that nourish post-zygotic stages, e.g. flowering plants and internally fertilising invertebrates, and consider how their sex allocation should respond to an environmental stress that reduces prospects of survival but does not affect all individuals equally, rather acting only on a subset of the population. Whereas dissemination of pollen and sperm can begin at sexual maturation, release of seeds and larvae is delayed by embryonic development. We find that the evolutionarily stable strategy for allocation between male and female functions will be critically dependent on the effect of stress on the trade-off between the costs of male and female reproduction, (i.e. of sperm and embryos). Thus, we identify evaluation of this factor as an important challenge to empiricists interested in the effects of stress on sex allocation. When only a small fraction of the population is stressed, we predict that stressed individuals will allocate their resources entirely to male function and unstressed individuals will increase their allocation to female function. Conversely, when the fraction of stress-affected individuals is high, stressed individuals should respond to this stressor by increasing investment in sperm and unstressed individuals should invest solely in embryos. A further prediction of the model is that we would not expect to find populations in the natural world where both stressed and unstressed individuals are both hermaphrodite
The Broadband Infrared Emission Spectrum of the Exoplanet TrES-3
We use the Spitzer Space Telescope to estimate the dayside thermal emission
of the exoplanet TrES-3 integrated in the 3.6, 4.5, 5.8, and 8.0 micron
bandpasses of the Infrared Array Camera (IRAC) instrument. We observe two
secondary eclipses and find relative eclipse depths of 0.00346 +/- 0.00035,
0.00372 +/- 0.00054, 0.00449 +/- 0.00097, and 0.00475 +/- 0.00046, respectively
in the 4 IRAC bandpasses. We combine our results with the earlier K band
measurement of De Mooij et al. (2009), and compare them with models of the
planetary emission. We find that the planet does not require the presence of an
inversion layer in the high atmosphere. This is the first very strongly
irradiated planet that does not have a temperature inversion, which indicates
that stellar or planetary characteristics other than temperature have an
important impact on temperature inversion. De Mooij & Snellen (2009) also
detected a possible slight offset in the timing of the secondary eclipse in K
band. However, based on our 4 Spitzer channels, we place a 3sigma upper limit
of |ecos(w)| < 0.0056 where e is the planets orbital eccentricity and w is the
longitude of the periastron. This result strongly indicates that the orbit is
circular, as expected from tidal circularization theory.Comment: Accepted by Ap
Equation-of-State Dependent Features in Shock-Oscillation Modulated Neutrino and Gravitational-Wave Signals from Supernovae
We present 2D hydrodynamic simulations of the long-time accretion phase of a
15 solar mass star after core bounce and before the launch of a supernova
explosion. Our simulations are performed with the Prometheus-Vertex code,
employing multi-flavor, energy-dependent neutrino transport and an effective
relativistic gravitational potential. Testing the influence of a stiff and a
soft equation of state for hot neutron star matter, we find that the non-radial
mass motions in the supernova core due to the standing accretion shock
instability (SASI) and convection impose a time variability on the neutrino and
gravitational-wave signals. These variations have larger amplitudes as well as
higher frequencies in the case of a more compact nascent neutron star. After
the prompt shock-breakout burst of electron neutrinos, a more compact accreting
remnant radiates neutrinos with higher luminosities and larger mean energies.
The observable neutrino emission in the direction of SASI shock oscillations
exhibits a modulation of several 10% in the luminosities and ~1 MeV in the mean
energies with most power at typical SASI frequencies of 20-100 Hz. At times
later than 50-100 ms after bounce the gravitational-wave amplitude is dominated
by the growing low-frequency (<200 Hz) signal associated with anisotropic
neutrino emission. A high-frequency wave signal is caused by nonradial gas
flows in the outer neutron star layers, which are stirred by anisotropic
accretion from the SASI and convective regions. The gravitational-wave power
then peaks at about 300-800 Hz with distinctively higher spectral frequencies
originating from the more compact and more rapidly contracting neutron star.
The detectability of the SASI effects in the neutrino and gravitational-wave
signals is briefly discussed. (abridged)Comment: 21 pages, 11 figures, 45 eps files; revised version including
discussion of signal detectability; accepted by Astronomy & Astrophysics;
high-resolution images can be obtained upon reques
Detection of a Temperature Inversion in the Broadband Infrared Emission Spectrum of TrES-4
We estimate the strength of the bandpass-integrated thermal emission from the
extrasolar planet TrES-4 at 3.6, 4.5, 5.8, and 8.0 micron using the Infrared
Array Camera (IRAC) on the Spitzer Space Telescope. We find relative eclipse
depths of 0.137 +/- 0.011%, 0.148 +/- 0.016%, 0.261 +/- 0.059%, and 0.318 +/-
0.044% in these four bandpasses, respectively. We also place a 2 sigma upper
limit of 0.37% on the depth of the secondary eclipse in the 16 micron IRS
peak-up array. These eclipse depths reveal that TrES-4 has an emission spectrum
similar to that of HD 209458b, which requires the presence of water emission
bands created by an thermal inversion layer high in the atmosphere in order to
explain the observed features. TrES-4 receives more radiation from its star
than HD 209458b and has a correspondingly higher effective temperature,
therefore the presence of a temperature inversion in this planet's atmosphere
lends support to the idea that inversions might be correlated with the
irradiance received by the planet. We find no evidence for any offset in the
timing of the secondary eclipse, and place a 3 sigma upper limit of
|ecos(omega)|<0.0058 where e is the planet's orbital eccentricity and omega is
the argument of pericenter. From this we conclude that tidal heating from
ongoing orbital circulatization is unlikely to be the explanation for TrES-4's
inflated radius.Comment: 10 pages in emulateapj format, 7 figures (some in color), accepted
for publication in Ap
Macroalgae contribute to the diet of Patella vulgata from contrasting conditions of latitude and wave exposure in the UK
Analysis of gut contents and stable isotope composition of intertidal limpets (Patella vulgata) showed a major contribution of macroalgae to their diet, along with microalgae and invertebrates. Specimens were collected in areas with limited access to attached macroalgae, suggesting a major dietary component of drift algae. Gut contents of 480 animals from 2 moderately wave exposed and 2 sheltered rocky shores in each of 2 regions: western Scotland (55–56°N) and southwest England (50°N), were analysed in 2 years (n = 30 per site per year). The abundance of microalgae, macroalgae and invertebrates within the guts was quantified using categorical abundance scales. Gut content composition was compared among regions and wave exposure conditions, showing that the diet of P. vulgata changes with both wave exposure and latitude. Microalgae were most abundant in limpet gut contents in animals from southwest sites, whilst leathery/corticated macroalgae were more prevalent and abundant in limpets from sheltered and northern sites. P. vulgata appears to have a more flexible diet than previously appreciated and these keystone grazers consume not only microalgae, but also large quantities of macroalgae and small invertebrates. To date, limpet grazing studies have focussed on their role in controlling recruitment of macroalgae by feeding on microscopic propagules and germlings. Consumption of adult algae suggests P. vulgata may also directly control the biomass of attached macroalgae on the shore, whilst consumption of drift algae indicates the species may play important roles in coupling subtidal and intertidal production
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