28 research outputs found
Observatory/data centre partnerships and the VO-centric archive: The JCMT Science Archive experience
We present, as a case study, a description of the partnership between an
observatory (JCMT) and a data centre (CADC) that led to the development of the
JCMT Science Archive (JSA). The JSA is a successful example of a service
designed to use Virtual Observatory (VO) technologies from the start. We
describe the motivation, process and lessons learned from this approach.Comment: Accepted for publication in the second Astronomy & Computing Special
Issue on the Virtual Observatory; 10 pages, 5 figure
A Genetic Algorithm-Based Exploration of Three Filament Models: A Case for the Magnetic Support of the G11.11-0.12 Infrared-Dark Cloud
The G11.11-0.12 infrared-dark cloud has a filamentary appearance, both in
extinction against the diffuse infrared emission of the Galactic plane and in
emission at 850 microns. We use a novel computational technique based on an
advanced genetic algorithm to explore thoroughly 3 different models of
self-gravitating, pressure truncated filaments and to constrain their
parameters. Specifically, the models tested are the non-magnetic Ostriker
(1964) model, a generalized version of the magnetic Stodolkiewicz (1963) model,
and the magnetic Fiege & Pudritz (2000) model. Previous results showed that
G11.11-0.12 has a much steeper r^{-4} radial density profile than other
filaments, where the density varies approximately as r^{-2}, and that this
steep density profile is consistent with the Ostriker (1964) model. We present
a more complete analysis that shows that the radial structure of G11.11-0.12 is
consistent with regimes of each of these models. All of the magnetic models
that agree with the data are threaded by a dominant poloidal magnetic field,
and most have dynamically significant fields. Thus, G11.11-0.12 is an excellent
candidate for radial support by a magnetic field that is predominantly
poloidal. We predict the polarization patterns expected for both magnetic
models and show that the two magnetic models produce different polarization
patterns that should be distingished by observations.Comment: To appear in Ap.J. Dec. 1 edition, volume 616. 40 pages and 42
figures. Figures are severely reduced to satisfy astro-ph size limits. A
version with higher quality figures is available by contacting the first
autho
Appraisal of literature reviews on end-of-life care for minority ethnic groups in the UK and a critical comparison with policy recommendations from the UK end-of-life care strategy
<p>Abstract</p> <p>Background</p> <p>Evidence of low end-of-life (EoL) care service use by minority ethnic groups in the UK has given rise to a body of research and a number of reviews of the literature. This article aims to review and evaluate literature reviews on minority ethnic groups and EoL care in the UK and assess their suitability as an evidence base for policy.</p> <p>Methods</p> <p>Systematic review. Searches were carried out in thirteen electronic databases, eight journals, reference lists, and grey literature. Reviews were included if they concerned minority ethnic groups and EoL care in the UK. Reviews were graded for quality and key themes identified.</p> <p>Results</p> <p>Thirteen reviews (2001-2009) met inclusion criteria. Seven took a systematic approach, of which four scored highly for methodological quality (a mean score of six, median seven). The majority of systematic reviews were therefore of a reasonable methodological quality. Most reviews were restricted by ethnic group, aspect of EoL care, or were broader reviews which reported relevant findings. Six key themes were identified.</p> <p>Conclusions</p> <p>A number of reviews were systematic and scored highly for methodological quality. These reviews provide a good reflection of the primary evidence and could be used to inform policy. The complexity and inter-relatedness of factors leading to low service use was recognised and reflected in reviews' recommendations for service improvement. Recommendations made in the UK End-of-Life Care Strategy were limited in comparison, and the Strategy's evidence base concerning minority ethnic groups was found to be narrow. Future policy should be embedded strongly in the evidence base to reflect the current literature and minimise bias.</p
Heritable symbionts in a world of varying temperature
Heritable microbes represent an important component of the biology, ecology and evolution of many plants, animals and fungi, acting as both parasites and partners. In this review, we examine how heritable symbiont–host interactions may alter host thermal tolerance, and how the dynamics of these interactions may more generally be altered by thermal environment. Obligate symbionts, those required by their host, are considered to represent a thermally sensitive weak point for their host, associated with accumulation of deleterious mutations. As such, these symbionts may represent an important determinant of host thermal envelope and spatial distribution. We then examine the varied relationship between thermal environment and the frequency of facultative symbionts that provide ecologically contingent benefits or act as parasites. We note that some facultative symbionts directly alter host thermotolerance. We outline how thermal environment will alter the benefits/costs of infection more widely, and additionally modulate vertical transmission efficiency. Multiple patterns are observed, with symbionts being cold sensitive in some species and heat sensitive in others, with varying and non-coincident thresholds at which phenotype and transmission are ablated. Nevertheless, it is clear that studies aiming to predict ecological and evolutionary dynamics of symbiont–host interactions need to examine the interaction across a range of thermal environments. Finally, we discuss the importance of thermal sensitivity in predicting the success/failure of symbionts to spread into novel species following natural/engineered introduction
Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases
The production of peroxide and superoxide is an inevitable consequence of
aerobic metabolism, and while these particular "reactive oxygen species" (ROSs)
can exhibit a number of biological effects, they are not of themselves
excessively reactive and thus they are not especially damaging at physiological
concentrations. However, their reactions with poorly liganded iron species can
lead to the catalytic production of the very reactive and dangerous hydroxyl
radical, which is exceptionally damaging, and a major cause of chronic
inflammation. We review the considerable and wide-ranging evidence for the
involvement of this combination of (su)peroxide and poorly liganded iron in a
large number of physiological and indeed pathological processes and
inflammatory disorders, especially those involving the progressive degradation
of cellular and organismal performance. These diseases share a great many
similarities and thus might be considered to have a common cause (i.e.
iron-catalysed free radical and especially hydroxyl radical generation). The
studies reviewed include those focused on a series of cardiovascular, metabolic
and neurological diseases, where iron can be found at the sites of plaques and
lesions, as well as studies showing the significance of iron to aging and
longevity. The effective chelation of iron by natural or synthetic ligands is
thus of major physiological (and potentially therapeutic) importance. As
systems properties, we need to recognise that physiological observables have
multiple molecular causes, and studying them in isolation leads to inconsistent
patterns of apparent causality when it is the simultaneous combination of
multiple factors that is responsible. This explains, for instance, the
decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference
Preparing data files for long-term archiving
With proper preparation, data files can be made easy to archive, informative for users who download the files from the archive, and ultimately rewarding for those who prepared the files. This paper sketches the Common Archive Object Model in use at the Canadian Astronomy Data Center, highlights key decisions that should be made as early as possible in the design of the files, and summarizes the metadata that should be included in each file.Peer reviewed: YesNRC publication: Ye