1,593 research outputs found
Evaluation Design and Technical Assistance Opportunities: Early Findings From the Beacon Community Program Evaluation Teams
Examines study designs, evaluation approaches, outcome measures, data sources, challenges, and technical assistance needs among sites in a project under the American Recovery and Reinvestment Act to strengthen health information technology capabilities
Control theory for principled heap sizing
We propose a new, principled approach to adaptive heap sizing based on control theory. We review current state-of-the-art heap sizing mechanisms, as deployed in Jikes RVM and HotSpot. We then formulate heap sizing as a control problem, apply and tune a standard controller algorithm, and evaluate its performance on a set of well-known benchmarks. We find our controller adapts the heap size more responsively than existing mechanisms. This responsiveness allows tighter virtual machine memory footprints while preserving target application throughput, which is ideal for both embedded and utility computing domains. In short, we argue that formal, systematic approaches to memory management should be replacing ad-hoc heuristics as the discipline matures. Control-theoretic heap sizing is one such systematic approach
Prediction of extubation outcome: a randomised, controlled trial with automatic tube compensation vs. pressure support ventilation
Trends in multimorbidity, complex multimorbidity and multiple functional limitations in the ageing population of England, 2002–2015
This is the final version. Available from SAGE via the DOI in this record.This study aimed to estimate the prevalence of three measures of multimorbidity among people aged 50 years or older in England. Beside the basic measure of two or more diseases within a person, we added a measure of three or more affected body systems (complex multimorbidity) and a measure of 10 or more functional limitations. We found that the three health outcomes became more prevalent between 2002 and 2015. They were more common among females than males and were becoming more common among younger age groups. While in 2002, the prevalence of basic multimorbidity overcame 50% from the 70–74 age group upwards, in 2015 it crossed the same threshold in the 65–69 age group. The distribution of multimorbidity and multiple functional limitations were stratified by the amount of household wealth. Multiple functional limitations reflected the largest differences between the most and the least affluent groups (5.9-fold in 2014/2015), followed by the measure of complex multimorbidity (2.8-fold in 2014/2015) and basic multimorbidity (1.9-fold) in 2014/2015.While age acted as a levelling factor for the wealth differences in basic multimorbidity, it had no such effect on the two other outcomes. Our study observed social polarization among multimorbid ageing population in England where complex multimorbidity and multiple functional limitations increase faster and reflect stronger inequality than basic multimorbidity
Environmental Benefits and Management of Small Grain Cover Crops in Corn-Soybean Rotations
These slides offer research results on cover crops
The First Two Years of Electromagnetic Follow-Up with Advanced LIGO and Virgo
We anticipate the first direct detections of gravitational waves (GWs) with
Advanced LIGO and Virgo later this decade. Though this groundbreaking technical
achievement will be its own reward, a still greater prize could be observations
of compact binary mergers in both gravitational and electromagnetic channels
simultaneously. During Advanced LIGO and Virgo's first two years of operation,
2015 through 2016, we expect the global GW detector array to improve in
sensitivity and livetime and expand from two to three detectors. We model the
detection rate and the sky localization accuracy for binary neutron star (BNS)
mergers across this transition. We have analyzed a large, astrophysically
motivated source population using real-time detection and sky localization
codes and higher-latency parameter estimation codes that have been expressly
built for operation in the Advanced LIGO/Virgo era. We show that for most BNS
events the rapid sky localization, available about a minute after a detection,
is as accurate as the full parameter estimation. We demonstrate that Advanced
Virgo will play an important role in sky localization, even though it is
anticipated to come online with only one-third as much sensitivity as the
Advanced LIGO detectors. We find that the median 90% confidence region shrinks
from ~500 square degrees in 2015 to ~200 square degrees in 2016. A few distinct
scenarios for the first LIGO/Virgo detections emerge from our simulations.Comment: 17 pages, 11 figures, 5 tables. For accompanying data, see
http://www.ligo.org/scientists/first2year
Association of lung clearance index with survival in individuals with cystic fibrosis.
BACKGROUND
The lung clearance index (LCI) assesses global ventilation inhomogeneity and is a sensitive biomarker of airway function in cystic fibrosis (CF) lung disease.
OBJECTIVES
We examined the association of LCI with the risk of death or lung transplantation (LTX) in individuals with CF.
METHODS
We performed a retrospective analysis in a cohort of individuals with CF aged≥5 years with LCI and FEV1 measurements performed between 1980 and 2006. The outcome was time until death or LTX. We used the earliest available LCI and FEV1 values in a Cox proportional hazard regression adjusted for demographic and clinical variables. For sensitivity analyses, we used the mean of the first three LCI and FEV1 measurements, stratified the cohort based on age, and investigated individuals with normal FEV1.
RESULTS
In total, 237 individuals with CF with a mean (range) age of 13.9 (5.6-41.0) years were included. The time-to-event analysis accrued 3813 person-years and 94 (40%) individuals died or received LTX. Crude hazard ratios [95% CI] were 1.04 [1.01-1.06] per one z-score increase in LCI and 1.25 [1.11-1.41] per one z-score decrease in FEV1. After adjusting LCI and FEV1 mutually in addition to sex, age, BMI and the number of hospitalisations, hazard ratios were 1.04 [1.01-1.07] for LCI, and 1.12 [0.95-1.33] for FEV1. Sensitivity analyses yielded similar results and using the mean LCI strengthened the associations.
CONCLUSIONS
Increased ventilation inhomogeneity is associated with greater risk of death or LTX. Our data support LCI as novel surrogate of survival in individuals with CF
Bi-Phasic Vesicles: instability induced by adsorption of proteins
The recent discovery of a lateral organization in cell membranes due to small
structures called 'rafts' has motivated a lot of biological and
physico-chemical studies. A new experiment on a model system has shown a
spectacular budding process with the expulsion of one or two rafts when one
introduces proteins on the membrane. In this paper, we give a physical
interpretation of the budding of the raft phase. An approach based on the
energy of the system including the presence of proteins is used to derive a
shape equation and to study possible instabilities. This model shows two
different situations which are strongly dependent on the nature of the
proteins: a regime of easy budding when the proteins are strongly coupled to
the membrane and a regime of difficult budding.Comment: 19 avr. 200
Counterintuitive transitions in multistate curve crossing involving linear potentials
Two problems incorporating a set of horizontal linear potentials crossed by a
sloped linear potential are analytically solved and compared with numerical
results: (a) the case where boundary conditions are specified at the ends of a
finite interval, and (b) the case where the sloped linear potential is replaced
by a piecewise-linear sloped potential and the boundary conditions are
specified at infinity. In the approximation of small gaps between the
horizontal potentials, an approach similar to the one used for the degenerate
problem (Yurovsky V A and Ben-Reuven A 1998 J. Phys. B 31,1) is applicable for
both problems. The resulting scattering matrix has a form different from the
semiclassical result obtained by taking the product of Landau-Zener amplitudes.
Counterintuitive transitions involving a pair of successive crossings, in which
the second crossing precedes the first one along the direction of motion, are
allowed in both models considered here.Comment: LaTeX 2.09 using ioplppt.sty and psfig.sty, 16 pages with 5 figures.
Submitted to J. Phys.
Parameter estimation on gravitational waves from neutron-star binaries with spinning components
Inspiraling binary neutron stars are expected to be one of the most
significant sources of gravitational-wave signals for the new generation of
advanced ground-based detectors. We investigate how well we could hope to
measure properties of these binaries using the Advanced LIGO detectors, which
began operation in September 2015. We study an astrophysically motivated
population of sources (binary components with masses
-- and spins of less than )
using the full LIGO analysis pipeline. While this simulated population covers
the observed range of potential binary neutron-star sources, we do not exclude
the possibility of sources with parameters outside these ranges; given the
existing uncertainty in distributions of mass and spin, it is critical that
analyses account for the full range of possible mass and spin configurations.
We find that conservative prior assumptions on neutron-star mass and spin lead
to average fractional uncertainties in component masses of , with
little constraint on spins (the median upper limit on the spin of the
more massive component is ). Stronger prior constraints on
neutron-star spins can further constrain mass estimates, but only marginally.
However, we find that the sky position and luminosity distance for these
sources are not influenced by the inclusion of spin; therefore, if LIGO detects
a low-spin population of BNS sources, less computationally expensive results
calculated neglecting spin will be sufficient for guiding electromagnetic
follow-up.Comment: 10 pages, 9 figure
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