1,556 research outputs found

    Evaluation Design and Technical Assistance Opportunities: Early Findings From the Beacon Community Program Evaluation Teams

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    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

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    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

    Trends in multimorbidity, complex multimorbidity and multiple functional limitations in the ageing population of England, 2002–2015

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    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

    The First Two Years of Electromagnetic Follow-Up with Advanced LIGO and Virgo

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    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.

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    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

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    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

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    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

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    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 1.2 M1.2~\mathrm{M}_\odot--1.6 M1.6~\mathrm{M}_\odot and spins of less than 0.050.05) 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 16%\sim 16\%, with little constraint on spins (the median 90%90\% upper limit on the spin of the more massive component is 0.7\sim 0.7). 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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