1,790 research outputs found
Implementing an Endocarditis Interdisciplinary Pathway in a Large Academic Medical Center: A Quality Improvement Project
Infective endocarditis (IE) is an infection and or inflammation of the heart valves and endocardium and a potentially life threatening illness. Dependent on the infecting organism, the cardiac damage caused by IE can be indolent or very aggressive. Hospitalized patients with IE require management by an interdisciplinary team, including cardiologists, cardiac surgeons, infectious disease specialists, registered nurses, nurse practitioners, physician assistants, pharmacists, and social workers. Treatment is complex and patients often present with various comorbidities. Standardized interdisciplinary care protocols have been shown to reduce patient mortality and hospital length of stay. The development of the pathway guidelines was informed by stakeholder meetings and recommendations from the American Heart Association, American Association for Thoracic Surgery, and European Society of Cardiology. One IE-related pathway was published in the institution’s intranet with two subsections: IE Diagnosis and IE Management and Discharge Processes. Education sessions on pathway access were conducted for interdisciplinary staff across three cardiac care units. The frequency of pathway online views was measured over three months, accumulating a total of 191 views. The median number of daily views was 2.5 [IQR 2, 4]. Analysis of these initial measures will help guide future efforts to streamline and enhance interdisciplinary collaboration amongst staff that care for patients with IE
Pore morphology evolution and atom distribution of doped Fe2O3 foams developed by freeze-casting after redox cycling
Chemical looping water splitting systems operate at relatively high
temperatures (450-800 degree C) to produce, purify, or store hydrogen by the
cyclic reduction and oxidation (redox) of a solid oxygen carrier. Therefore, to
improve long-term operation, it is necessary to develop highly stable oxygen
carriers with large specific surface areas. In this work, highly interconnected
doped Fe2O3 foams are fabricated through the freeze-casting technique, and the
aid of a submicrometric camphene-based suspension to prevent Fe sintering and
pore clogging during redox operation. The influence of the dopant elements (Al
and Ce) over the pore morphology evolution, and redox performances are
examined. The use of an Fe2O3 porous structure with initial pore size above 100
microns shows a significant reduction of the sample densification, and the
addition of Al2O3 by the co-precipitation process proves to be beneficial in
preventing the generation of a core-shell structure following redox processing.Comment: 25 pages, 8 figure
Quantum dissipation due to the interaction with chaotic degrees-of-freedom and the correspondence principle
Both in atomic physics and in mesoscopic physics it is sometimes interesting
to consider the energy time-dependence of a parametrically-driven chaotic
system. We assume an Hamiltonian where . The
velocity is slow in the classical sense but not necessarily in the
quantum-mechanical sense. The crossover (in time) from ballistic to diffusive
energy-spreading is studied. The associated irreversible growth of the average
energy has the meaning of dissipation. It is found that a dimensionless
velocity determines the nature of the dynamics, and controls the route
towards quantal-classical correspondence (QCC). A perturbative regime and a
non-perturbative semiclassical regime are distinguished.Comment: 4 pages, clear presentation of the main poin
Prevention, screening and treatment of colorectal cancer: a global and regional generalized cost effectiveness analysis
<p>Abstract</p> <p>Background</p> <p>Regional generalized cost-effectiveness estimates of prevention, screening and treatment interventions for colorectal cancer are presented.</p> <p>Methods</p> <p>Standardised WHO-CHOICE methodology was used. A colorectal cancer model was employed to provide estimates of screening and treatment effectiveness. Intervention effectiveness was determined via a population state-transition model (PopMod) that simulates the evolution of a sub-regional population accounting for births, deaths and disease epidemiology. Economic costs of procedures and treatment were estimated, including programme overhead and training costs.</p> <p>Results</p> <p>In regions characterised by high income, low mortality and high existing treatment coverage, the addition of screening to the current high treatment levels is very cost-effective, although no particular intervention stands out in cost-effectiveness terms relative to the others.</p> <p>In regions characterised by low income, low mortality with existing treatment coverage around 50%, expanding treatment with or without screening is cost-effective or very cost-effective. Abandoning treatment in favour of screening (no treatment scenario) would not be cost effective.</p> <p>In regions characterised by low income, high mortality and low treatment levels, the most cost-effective intervention is expanding treatment.</p> <p>Conclusions</p> <p>From a cost-effectiveness standpoint, screening programmes should be expanded in developed regions and treatment programmes should be established for colorectal cancer in regions with low treatment coverage.</p
Analysing Lyapunov spectra of chaotic dynamical systems
It is shown that the asymptotic spectra of finite-time Lyapunov exponents of
a variety of fully chaotic dynamical systems can be understood in terms of a
statistical analysis. Using random matrix theory we derive numerical and in
particular analytical results which provide insights into the overall behaviour
of the Lyapunov exponents particularly for strange attractors. The
corresponding distributions for the unstable periodic orbits are investigated
for comparison.Comment: 4 pages, 4 figure
Technical note: Skirt chamber – an open dynamic method for the rapid and minimally intrusive measurement of greenhouse gas emissions from peatlands
We present a reliable and robust open dynamic chamber for
measuring greenhouse gas exchange in peatlands with minimal disturbance of
the ground. This chamber, called the “skirt chamber”, is based on a
transparent plastic film placed above an open frame made of sparse
interwoven wires and expanded around the base of the chamber below a steel
chain that ensures contact to the ground, avoiding damage, trenching, and
cutting vegetation. Gas exchange is determined using a portable gas analyzer
from a mass balance in which the imperfect sealing of the chamber to the
ground is quantified through the injection of a methane pulse. The method was
tested on a pristine peatland dominated by Sphagnum magellanicum located on Navarino Island in
the subantarctic Magellanic ecoregion in Chile. Our results indicate that
the skirt chamber allowed the determination of methane fluxes and ecosystem
respiration in about 20 min, with a limit of detection of 0.185 mg
CH4 m−2 h−1 and 173 mg CO2 m−2 h−1,
respectively. We conclude that the skirt chamber is a minimally intrusive,
fast, portable, and inexpensive method that allows the quantification of
greenhouse gas emissions with high spatial resolution in remote locations
and without delay.</p
Semiclassical analysis of the quantum interference corrections to the conductance of mesoscopic systems
The Kubo formula for the conductance of a mesoscopic system is analyzed
semiclassically, yielding simple expressions for both weak localization and
universal conductance fluctuations. In contrast to earlier work which dealt
with times shorter than , here longer times are taken to
give the dominant contributions. For such long times, many distinct classical
orbits may obey essentially the same initial and final conditions on positions
and momenta, and the interference between pairs of such orbits is analyzed.
Application to a chain of classically ergodic scatterers connected in
series gives the following results: for the
weak localization correction to the zero--temperature dimensionless
conductance, and for the variance of its
fluctuations. These results interpolate between the well known ones of random
scattering matrices for , and those of the one--dimensional diffusive wire
for .Comment: 53 pages, using RevTeX, plus 3 postscript figures mailed separately.
A short version of this work is available as cond-mat/950207
Spitzer Observations of IC 2118
IC 2118, also known as the Witch Head Nebula, is a wispy, roughly cometary,
~5 degree long reflection nebula, and is thought to be a site of triggered star
formation. In order to search for new young stellar objects (YSOs), we have
observed this region in 7 mid- and far-infrared bands using the Spitzer Space
Telescope and in 4 bands in the optical using the U. S. Naval Observatory
40-inch telescope. We find infrared excesses in 4 of the 6 previously-known T
Tauri stars in our combined infrared maps, and we find 6 entirely new candidate
YSOs, one of which may be an edge-on disk. Most of the YSOs seen in the
infrared are Class II objects, and they are all in the "head" of the nebula,
within the most massive molecular cloud of the region.Comment: Accepted to Ap
Episodic photic zone euxinia in the northeastern Panthalassic Ocean during the end-Triassic extinction
Severe changes in ocean redox, nutrient cycling, and marine productivity accompanied most Phanerozoic mass extinctions. However, evidence for marine photic zone euxinia (PZE) as a globally important extinction mechanism for the end-Triassic extinction (ETE) is currently lacking. Fossil molecular (biomarker) and nitrogen isotopic records from a sedimentary sequence in western Canada provide the first conclusive evidence of PZE and disrupted biogeochemistry in neritic waters of the Panthalassic Ocean during the end Triassic. Increasing water-column stratification and deoxygenation across the ETE led to PZE in the Early Jurassic, paralleled by a perturbed nitrogen cycle and ecological turnovers among noncalcifying groups, including eukaryotic algae and prokaryotic plankton. If such conditions developed widely in the Panthalassic Ocean, PZE might have been a potent mechanism for the ETE.National Science Foundation (U.S.) (Grant EAR-1147402)Exobiology Program (U.S.) (Grants NNX09AM88G and NNA08CN84A)American Association of Petroleum Geologists (Grant-In-Aid)Mary-Hill and Bevan M. French Fund for Impact Geolog
Computational Method for Phase Space Transport with Applications to Lobe Dynamics and Rate of Escape
Lobe dynamics and escape from a potential well are general frameworks
introduced to study phase space transport in chaotic dynamical systems. While
the former approach studies how regions of phase space are transported by
reducing the flow to a two-dimensional map, the latter approach studies the
phase space structures that lead to critical events by crossing periodic orbit
around saddles. Both of these frameworks require computation with curves
represented by millions of points-computing intersection points between these
curves and area bounded by the segments of these curves-for quantifying the
transport and escape rate. We present a theory for computing these intersection
points and the area bounded between the segments of these curves based on a
classification of the intersection points using equivalence class. We also
present an alternate theory for curves with nontransverse intersections and a
method to increase the density of points on the curves for locating the
intersection points accurately.The numerical implementation of the theory
presented herein is available as an open source software called Lober. We used
this package to demonstrate the application of the theory to lobe dynamics that
arises in fluid mechanics, and rate of escape from a potential well that arises
in ship dynamics.Comment: 33 pages, 17 figure
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