88,411 research outputs found
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CO J = 3→2 and J = 2→1 mapping and spectroscopy of NGC 7027
We present spectra and mapping for NGC 7072 in the J = 3→2 and J = 2→1 transitions of CO. The central profile at J = 2→1 is shown to be very similar to the J = 1→0 spectrum measured by Thronson (1983), and this implies a source expansion at roughly constant velocity. The J = 3→2 line however appears weaker, with evidence for appreciable quenching of the higher velocity components. Detailed modelling f the source indicates that densities n must vary appreciably with shell radius R(as nα R-a, where α≥2), and this leads to a corresponding steep radial decrease in the radiation temperature TR. In consequence, the source FWHM is found to decrease appreciably iwth increasing transition frequency, a trend which appears also to be confirmed by our central J = 3→2 scans. It is not however possible to constrain gas kinetic tempertures TK, the level of CO thermalisation, or shell mass M with any degree of confidence - both low and high mass models appear capable of replicating our spectra.
Finally, the J = 2→1 spatial velocity map displays evidence for a decrease in velocity width towards the outer regions of the nebula; a feature which is expected of most outflow models. The J = 3→2 map also indicates the presence of a nebular extension to the north-west of the peak emission core, although this is not reproduced in the corresponding J = 1→0 map of Mufson et al. (1975)
Forbidden Line Emission in the Eccentric Spectroscopic Binaries DQ Tauri and UZ Tauri E Monitored over an Orbital Period
We present echelle spectroscopy of the close pre-main-sequence binary star
systems DQ Tau and UZ Tau-E. Over a 16 day time interval we acquired 14 nights
of spectra for DQ Tau and 12 nights of spectra for UZ Tau-E. This represents
the entire phase of DQ Tau, and 63 percent of the phase of UZ Tau-E. As
expected, photospheric lines such as Li I 6707 clearly split into two
components as the primary and secondary orbit one another, as did the permitted
line He I 5876. Unlike the photospheric features, the forbidden lines of [O I]
6300 and [O I] 5577, retain the same shape throughout the orbit. Therefore
these lines must originate outside of the immediate vicinity of the two stars
and any circumstellar disks that participate in the orbital motion of the
stars.Comment: 14 pages including 6 figures, aastex preprint, accepted to
Astronomical Journa
Roles, service knowledge and priorities in the provision of palliative care: a postal survey of London GPs
Objectives: To explore general practitioners' (GPs) current involvement in and attitudes towards the provision of palliative care in primary care. Methods: Postal survey of 356 London-based GPs, assessing attitudes towards palliative care provision, district nursing and specialist palliative care services, and priorities for future service development. Results: Currently, 65% of GPs were providing palliative care to patients on their list; 72% agreed or strongly agreed palliative care was a central part of their role; and 27% wanted to hand care over to specialists. Most GPs (66%) disagreed with the statement that 'palliative care is mainly district nursing (DN) work'. Many were unaware of out-of-hours DN and specialist palliative care services. Multi-variable analysis found four GP characteristics - larger practice size, more years experience as a GP, receipt of palliative care education, and current provision of palliative care - were associated with agreement that palliative care was central to a GP's role. Conclusion: A minority of NHS GPs in London would rather have no involvement in palliative care in primary care. Knowledge of current services for palliative care is generally poor among GPs. These findings highlight potential gaps in services, particularly in small practices. Specialists will need to consider these factors in working with GPs to develop primary palliative care and to enable greater access to specialist palliative care
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Flood- and Weather-Damaged Homes and Mental Health: An Analysis Using England's Mental Health Survey
There is increasing evidence that exposure to weather-related hazards like storms and floods adversely affects mental health. However, evidence of treated and untreated mental disorders based on diagnostic criteria for the general population is limited. We analysed the Adult Psychiatric Morbidity Survey, a large probability sample survey of adults in England (n = 7525), that provides the only national data on the prevalence of mental disorders assessed to diagnostic criteria. The most recent survey (2014–2015) asked participants if they had experienced damage to their home (due to wind, rain, snow or flood) in the six months prior to interview, a period that included months of unprecedented population exposure to flooding, particularly in Southern England. One in twenty (4.5%) reported living in a storm- or flood-damaged home in the previous six months. Social advantage (home ownership, higher household income) increased the odds of exposure to storm or flood damage. Exposure predicted having a common mental disorder over and above the effects of other known predictors of poor mental health. With climate change increasing the frequency and severity of storms and flooding, improving community resilience and disaster preparedness is a priority. Evidence on the mental health of exposed populations is key to building this capacity
An empirical evaluation of four variants of a universal species-area relationship
The Maximum Entropy Theory of Ecology (METE) predicts a universal
species-area relationship (SAR) that can be fully characterized using only the
total abundance (N) and species richness (S) at a single spatial scale. This
theory has shown promise for characterizing scale dependence in the SAR.
However, there are currently four different approaches to applying METE to
predict the SAR and it is unclear which approach should be used due to a lack
of empirical evaluation. Specifically, METE can be applied recursively or a
non-recursively and can use either a theoretical or observed species-abundance
distribution (SAD). We compared the four different combinations of approaches
using empirical data from 16 datasets containing over 1000 species and 300,000
individual trees and herbs. In general, METE accurately downscaled the SAR
(R^2> 0.94), but the recursive approach consistently under-predicted richness,
and METEs accuracy did not depend strongly on using the observed or predicted
SAD. This suggests that best approach to scaling diversity using METE is to use
a combination of non-recursive scaling and the theoretical abundance
distribution, which allows predictions to be made across a broad range of
spatial scales with only knowledge of the species richness and total abundance
at a single scale.Comment: main text: 20 pages, 2 tables, 3 figure
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Near infrared spectroscopy of W51 IRS-2
Near-infrared spectra at 2.95-3.5 μm and 3.99-10 μm have been obtained towards W51 IRS-2 and its surroundings, in order to investigate the spatial variations in intensity of the 3.28 μm unidentified feature and the 4.05 μm Brackett-α line. The Br-α and 3.28 μm features occupy a broadly similar spatial zone, which is characterised by an unresolved core responsible for most of the emission, and an extended and considerably weaker halo. Grain properties required to excite the 4.28 microns line, the nature of the 3.28 μm emission, and its relation to the source structure are discussed
Weak Lensing as a Calibrator of the Cluster Mass-Temperature Relation
The abundance of clusters at the present epoch and weak gravitational lensing
shear both constrain roughly the same combination of the power spectrum
normalization sigma_8 and matter energy density Omega_M. The cluster constraint
further depends on the normalization of the mass-temperature relation.
Therefore, combining the weak lensing and cluster abundance data can be used to
accurately calibrate the mass-temperature relation. We discuss this approach
and illustrate it using data from recent surveys.Comment: Matches the version in ApJL. Equation 4 corrected. Improvements in
the analysis move the cluster contours in Fig1 slightly upwards. No changes
in the conclusion
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