284 research outputs found
Using the 'myVolcano' mobile phone app for citizen science in St. Vincent and the Grenadines : a pilot study
The British Geological Survey (BGS) has been working with Caribbean partners on the role of
citizen science in increasing resilience to natural hazards. The work has largely focused on the
potential use of the myVolcano smartphone app, which was developed by the BGS following the
2010 Eyafjallajökull and 2011 GrÃmsvötn eruptions in Iceland. During these eruptions the BGS
asked the UK public to collect particle samples, subsequently analysing these for ash presence to
map the distribution of ash fallout across the UK. These requests led to the development of the
myVolcano app, which was designed to capture transboundary and distal observations of volcanic
ash and emissions. The observations are made visible to other users via an interactive map built
into the app. The map interface has global coverage and the data collection methods (free-text
descriptions and photographs) are such that information about any natural hazard, anywhere in the
world, can be captured.
In 2015, BGS carried out an ESRC-DfID-NERC funded scoping study in collaboration with the
University of the West Indies’ Seismic Research Centre (UWI SRC), to test the potential use of
the app in environments affected by proximal volcanic hazards. The study focused on St. Vincent
and the Grenadines and investigated the potential for capturing a wider variety of observations for
use by the public, operational scientists and civil protection. The study, which included a
combination of desk study and remote interviews, highlighted the potential for, and challenges of,
using such an app for increasing resilience to natural hazards and the need for a follow-up study
in St Vincent.
In March 2017, a workshop and school activities were held in St. Vincent to collect feedback from
potential users of myVolcano, hereafter referred to as the pilot study. Workshop participants came
from across government, monitoring agencies, emergency response and telecommunications. As
part of the workshop, a multi-hazard scenario was ‘played out’ to stimulate discussions on the
usability of the app, data gathering and processing, and participants’ use of existing citizen science
applications. Discussions developed around data validation and quality assurance, data sharing and
presentation, local management of data by nominated scientists (e.g. to facilitate real-time decision
making) and the associated need for a locally appropriate app (i.e. no one size fits all). This last
point is particularly significant when considering the utility of an app in several countries – the
user interface, at least, requires specific tailoring to the country’s needs. Using this feedback, the
BGS Official Development Assistance (ODA) programme is currently funding collaborations
with Caribbean partners in order to modify the app to meet the local requirements, including
widening the multi-hazard application and enhancing two-way information sharing. Of particular
importance is how best to share critical information with those making observations and how to
make observations available to decision-makers and monitoring scientists in real-time (e.g.
through local management of the app)
Dissecting the Red Sequence--II. Star Formation Histories of Early-Type Galaxies Throughout the Fundamental Plane
This analysis uses spectra of ~16,000 nearby SDSS quiescent galaxies to track
variations in galaxy star formation histories along and perpendicular to the
Fundamental Plane (FP). We sort galaxies by their FP properties (sigma, R_e,
and I_e) and construct high S/N mean galaxy spectra that span the breadth and
thickness of the FP. From these spectra, we determine mean luminosity-weighted
ages, [Fe/H], [Mg/H], and [Mg/Fe] based on single stellar population models
using the method described in Graves & Schiavon (2008). In agreement with
previous work, the star formation histories of early-type galaxies are found to
form a two-parameter family. The major trend is that mean age, [Fe/H], [Mg/H],
and [Mg/Fe] all increase with sigma. However, no stellar population property
shows any dependence on R_e at fixed sigma, suggesting that sigma and not
dynamical mass (M_dyn ~ sigma^2 R_e) is the better predictor of past star
formation history. In addition to the main trend with sigma, galaxies also show
a range of population properties at fixed sigma that are strongly correlated
with surface brightness residuals from the FP, such that higher surface
brightness galaxies have younger mean ages, higher [Fe/H], higher [Mg/H], and
lower [Mg/Fe] than lower-surface brightness galaxies. These latter trends are a
major new constraint on star-formation histories.Comment: 23 pages, 14 figures. Accepted to Ap
Healthcare disparities for women hospitalised with myocardial infarction and angina
Ischaemic heart disease persists as the leading global cause of death. Myocardial infarction (MI) accounts for a large proportion of death due to cardiovascular disease. Between 2007 and 2016, age-sex standardised mortality for MI in Scotland has fallen by 42.5% from 129 to 74 per 100,000 population – a trend also apparent in other countries. Despite improvements in survival, considerable disparities exist according to sexin terms of delivery of guideline-recommended treatments and outcomes following MI suggesting women may be disadvantaged. Use of high-sensitivity troponin assays with sex-specific thresholds increases the detection of MI in women. However, women are less likely to undergo percutaneous coronary revascularisation (PCI) and are more often subject to underutilisation of evidence-based secondary preventative pharmacotherapy. Differences in adoption of invasive management may, in part, be explained by a perception held by clinicians and patients that outcomes are worse for women receiving PCI, as well as differences in symptoms and baseline risk profile which may impact clinical decision-making. Adverse events post-MI, including cardiogenic shock, heart failure and death, remain more common in women than in men, most notably in those with ST-elevation myocardial infarction (STEMI). Whether sex remains an independent predictor of adverse events despite adjustments for the higher risk-profile of women, notably age, is less clear. We hypothesised that sex-related differences in demographics and comorbidity underpin disparities in management and outcomes of women and men hospitalised with MI or angina. We investigated this hypothesis by analysis of a contemporary secondary care electronic registry (e-Registry) using electronic patient records (EPRs) for patients admitted to a complex regional healthcare network.PostprintPeer reviewe
Dissecting the Red Sequence. IV. The Role of Truncation in the Two-Dimensional Family of Early-Type Galaxy Star Formation Histories
In the three-dimensional parameter space defined by velocity dispersion,
effective radius (R_e), and effective surface brightness (I_e), early-type
galaxies are observed to populate a two-dimensional fundamental plane (FP) with
finite thickness. In Paper III of this series, we showed that the thickness of
the FP is predominantly due to variations in the stellar mass surface density
(Sigma_*) inside the effective radius R_e. These variations represent
differences in the dark matter fraction inside R_e (or possibly differences in
the initial mass function) from galaxy to galaxy. This means that galaxies do
not wind up below the FP at lower surface brightness due to the passive fading
of their stellar populations; they are structurally different. Here, we show
that these variations in Sigma_* at fixed dynamical mass (M_dyn) are linked to
differences in the galaxy stellar populations, and therefore to differences in
their star formation histories. We demonstrate that the ensemble of stellar
population and Sigma_* variations through the FP thickness can be explained by
a model in which early-type galaxies at fixed M_dyn have their star formation
truncated at different times. The thickness of the FP can therefore be
interpreted as a sequence of truncation times. Galaxies below the FP have
earlier truncation times for a given M_dyn, resulting in lower Sigma_*, older
ages, lower metallicities in both [Fe/H] and [Mg/H], and higher [Mg/Fe]. We
show that this model is quantitatively consistent with simple expectations for
chemical enrichment in galaxies. We also present fitting functions for
luminosity-weighted age, [Fe/H], [Mg/H], and [Mg/Fe] as functions of the FP
parameters velocity dispersion, R_e, and I_e. These provide a new tool for
estimating the stellar population properties of quiescent early-type galaxies
for which high-quality spectra are not available.Comment: 21 pages, 9 figures. Accepted to Ap
Tamoxifen for prevention of breast cancer: extended long-term follow-up of the IBIS-I breast cancer prevention trial
© Cuzick et al. Open Access article distributed under the terms of CC BY.http://dx.doi.org/10.1016/S1470-2045(14)71171-
Xanthine oxidase inhibition and white matter hyperintensity progression following ischaemic stroke and transient ischaemic attack (XILO-FIST): a multicentre, double-blinded, randomised, placebo-controlled trial
BACKGROUND:
People who experience an ischaemic stroke are at risk of recurrent vascular events, progression of cerebrovascular disease, and cognitive decline. We assessed whether allopurinol, a xanthine oxidase inhibitor, reduced white matter hyperintensity (WMH) progression and blood pressure (BP) following ischaemic stroke or transient ischaemic attack (TIA).
METHODS:
In this multicentre, prospective, randomised, double-blinded, placebo-controlled trial conducted in 22 stroke units in the United Kingdom, we randomly assigned participants within 30-days of ischaemic stroke or TIA to receive oral allopurinol 300 mg twice daily or placebo for 104 weeks. All participants had brain MRI performed at baseline and week 104 and ambulatory blood pressure monitoring at baseline, week 4 and week 104. The primary outcome was the WMH Rotterdam Progression Score (RPS) at week 104. Analyses were by intention to treat. Participants who received at least one dose of allopurinol or placebo were included in the safety analysis. This trial is registered with ClinicalTrials.gov, NCT02122718.
FINDINGS:
Between 25th May 2015 and the 29th November 2018, 464 participants were enrolled (232 per group). A total of 372 (189 with placebo and 183 with allopurinol) attended for week 104 MRI and were included in analysis of the primary outcome. The RPS at week 104 was 1.3 (SD 1.8) with allopurinol and 1.5 (SD 1.9) with placebo (between group difference −0.17, 95% CI −0.52 to 0.17, p = 0.33). Serious adverse events were reported in 73 (32%) participants with allopurinol and in 64 (28%) with placebo. There was one potentially treatment related death in the allopurinol group.
INTERPRETATION:
Allopurinol use did not reduce WMH progression in people with recent ischaemic stroke or TIA and is unlikely to reduce the risk of stroke in unselected people.
FUNDING:
The British Heart Foundation and the UK Stroke Association
A review of elliptical and disc galaxy structure, and modern scaling laws
A century ago, in 1911 and 1913, Plummer and then Reynolds introduced their
models to describe the radial distribution of stars in `nebulae'. This article
reviews the progress since then, providing both an historical perspective and a
contemporary review of the stellar structure of bulges, discs and elliptical
galaxies. The quantification of galaxy nuclei, such as central mass deficits
and excess nuclear light, plus the structure of dark matter halos and cD galaxy
envelopes, are discussed. Issues pertaining to spiral galaxies including dust,
bulge-to-disc ratios, bulgeless galaxies, bars and the identification of
pseudobulges are also reviewed. An array of modern scaling relations involving
sizes, luminosities, surface brightnesses and stellar concentrations are
presented, many of which are shown to be curved. These 'redshift zero'
relations not only quantify the behavior and nature of galaxies in the Universe
today, but are the modern benchmark for evolutionary studies of galaxies,
whether based on observations, N-body-simulations or semi-analytical modelling.
For example, it is shown that some of the recently discovered compact
elliptical galaxies at 1.5 < z < 2.5 may be the bulges of modern disc galaxies.Comment: Condensed version (due to Contract) of an invited review article to
appear in "Planets, Stars and Stellar
Systems"(www.springer.com/astronomy/book/978-90-481-8818-5). 500+ references
incl. many somewhat forgotten, pioneer papers. Original submission to
Springer: 07-June-201
Disentangling sequential and concerted fragmentations of molecular polycations with covariant native frame analysis
Using covariance analysis methods, we study the fragmentation dynamics of multiply ionized 1- and 2-iodopropane. Signatures of isomer-specific nuclear motion occurring during sequential fragmentation pathways are identified.</jats:p
Direct momentum imaging of charge transfer following site-selective ionization
We study ultrafast charge rearrangement in dissociating 2-iodopropane (2−C3H7I) using site-selective core ionization at the iodine atom. Clear signatures of electron transfer between the neutral propyl fragment and multiply charged iodine ions are observed in the recorded delay-dependent ion momentum distributions. The detected charge-transfer pathway is only favorable within a small (few angstroms), charge-state-dependent spatial window located at C-I distances longer than that of the neutral ground-state molecule. These results offer insights into the physics underpinning charge transfer in isolated molecules and pave the way for a different class of time-resolved studies
The Demise of Islet Allotransplantation in the US: A Call for an Urgent Regulatory Update The ISLETS FOR US Collaborative
Islet allotransplantation in the United States (US) is facing an imminent demise. Despite nearly three decades of progress in the field, an archaic regulatory framework has stymied US clinical practice. Current regulations do not reflect the state-of-the-art in clinical or technical practices. In the US, islets are considered biologic drugs and more than minimally manipulated human cell and tissue products (HCT/Ps). Across the world, human islets are appropriately defined as minimally manipulated tissue which has led to islet transplantation becoming a standard-of-care procedure for patients with type 1 diabetes mellitus and problematic hypoglycemia. As a result of the outdated US regulations, only eleven patients underwent allo-ITx in the US between 2011-2016 and all in the setting of a clinical trial. Herein, we describe the current regulations pertaining to islet transplantation in the United States. We explore the progress which has been made in the field and demonstrate why the regulatory framework must be updated to both, better reflect our current clinical practice and to deal with upcoming challenges. We propose specific updates to current regulations which are required for the renaissance of ethical, safe, effective, and affordable allo-ITx in the United States
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