906 research outputs found
Use of cumulative mortality data in patients with acute myocardial infarction for early detection of variation in clinical practice: observational study
OBJECTIVES: Use of cumulative mortality adjusted for
case mix in patients with acute myocardial infarction
for early detection of variation in clinical practice.
DESIGN: Observational study.
SETTING: 20 hospitals across the former Yorkshire
region.
PARTICIPANTS: All 2153 consecutive patients with
confirmed acute myocardial infarction identified
during three months.
MAIN OUTCOME MEASURES: Variable lifeadjusted
displays showing cumulative differences between
observed and expected mortality of patients; expected
mortality calculated from risk model based on
admission characteristics of age, heart rate, and
systolic blood pressure.
RESULTS: The performance of two individual hospitals
over three months was examined as an example. One,
the smallest district hospital in the region, had a series
of 30 consecutive patients but had five more deaths
than predicted. The variable lifeadjusted display
showed minimal variation from that predicted for the
first 15 patients followed by a run of unexpectedly
high mortality. The second example was the main
tertiary referral centre for the region, which admitted
188 consecutive patients. The display showed a period
of apparently poor performance followed by
substantial improvement, where the plot rose steadily
from a cumulative net lives saved of - 4 to 7. These
variations in patient outcome are unlikely to have
been revealed during conventional audit practice.
CONCLUSIONS: Variable lifeadjusted display has been
integrated into surgical care as a graphical display of
riskadjusted survival for individual surgeons or centres.
In combination with a simple risk model, it may have a
role in monitoring performance and outcome in
patients with acute myocardial infarction
Metafluid dynamics and Hamilton-Jacobi formalism
Metafluid dynamics was investigated within Hamilton-Jacobi formalism and the
existence of the hidden gauge symmetry was analyzed. The obtained results are
in agreement with those of Faddeev-Jackiw approach.Comment: 7 page
Scattering of light and atoms in a Fermi-Dirac gas with BCS pairing
We theoretically study the optical properties of a Fermi-Dirac gas in the
presence of a superfluid state. We calculate the leading quantum-statistical
corrections to the standard column density result of the electric
susceptibility. We also consider the Bragg diffraction of atoms by means of
light-stimulated transitions of photons between two intersecting laser beams.
Bardeen-Cooper-Schrieffer pairing between atoms in different internal levels
magnifies incoherent scattering processes. The absorption linewidth of a
Fermi-Dirac gas is broadened and shifted. Bardeen-Cooper-Schrieffer pairing
introduces a collisional local-field shift that may dramatically dominate the
Lorentz-Lorenz shift. For the case of the Bragg spectroscopy the static
structure function may be significantly increased due to superfluidity in the
nearforward scattering.Comment: 13 pages, 6 figures; to appear in PR
On the growth of perturbations in interacting dark energy and dark matter fluids
The covariant generalizations of the background dark sector coupling
suggested in G. Mangano, G. Miele and V. Pettorino, Mod. Phys. Lett. A 18, 831
(2003) are considered. The evolution of perturbations is studied with detailed
attention to interaction rate that is proportional to the product of dark
matter and dark energy densities. It is shown that some classes of models with
coupling of this type do not suffer from early time instabilities in strong
coupling regime.Comment: 11 pages, 2 figures. v3: minor changes, typos fixe
Domain and Antidomain Semigroups
Abstract. We axiomatise and study operations for relational domain and antidomain on semigroups and monoids. We relate this approach with previous axiomatisations for semirings, partial transformation semi-groups and dynamic predicate logic.
Tragedy revisited
“Freedom in a commons brings ruin to all.” So argued ecologist Garrett Hardin in “The Tragedy of the Commons” in the 13 December 1968 issue of Science (1). Hardin questioned society's ability to manage shared resources and avoid an environmentally and socially calamitous free-for-all. In the 50 years since, the essay has influenced discussions ranging from climate change (see page 1217) to evolution, from infectious disease to the internet, and has reached far beyond academic literature—but not without criticism. Considerable work, notably by Nobelist Elinor Ostrom (2), has challenged Hardin, particularly his emphasis on property rights and government regulatory leviathans as solutions. Instead, research has documented contexts, cases, and principles that reflect the ability of groups to collectively govern common resources. To mark this anniversary and celebrate the richness of research and practice around commons and cooperation, Science invited experts to share some contemporary views on such tragedies and how to avert them. —Brad Wibl
Constraints on food choices of women in the UK with lower educational attainment
Constraints on food choices of women in the UK with lower educational attainmen
Generation and evolution of vortex-antivortex pairs in Bose-Einstein condensates
We propose a method for generating and controlling a spatially separated
vortex--antivortex pair in a Bose-Einstein condensate trapped in a toroidal
potential. Our simulations of the time dependent Gross-Pitaevskii equation show
that in toroidal condensates vortex dynamics are different from the dynamics in
the homogeneous case. Our numerical results agree well with analytical
calculations using the image method. Our proposal offers an effective example
of coherent generation and control of vortex dynamics in atomic condensates.Comment: 4 pages, 2 figure
SRAO CO Observation of 11 Supernova Remnants in l = 70 to 190 deg
We present the results of 12CO J = 1-0 line observations of eleven Galactic
supernova remnants (SNRs) obtained using the Seoul Radio Astronomy Observatory
(SRAO) 6-m radio telescope. The observation was made as a part of the SRAO CO
survey of SNRs between l = 70 and 190 deg, which is intended to identify SNRs
interacting with molecular clouds. The mapping areas for the individual SNRs
are determined to cover their full extent in the radio continuum. We used
halfbeam grid spacing (60") for 9 SNRs and full-beam grid spacing (120") for
the rest. We detected CO emission towards most of the remnants. In six SNRs,
molecular clouds showed a good spatial relation with their radio morphology,
although no direct evidence for the interaction was detected. Two SNRs are
particularly interesting: G85.4+0.7, where there is a filamentary molecular
cloud along the radio shell, and 3C434.1, where a large molecular cloud appears
to block the western half of the remnant. We briefly summarize the results
obtained for individual SNRs.Comment: Accepted for publication in Astrophysics & Space Science. 12 pages,
12 figures, and 3 table
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