577 research outputs found
Hospitalist Staffing and Patient Satisfaction in the National Medicare Population
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/96722/1/jhm2001.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/96722/2/jhm2001-sup-0001-suppinfo.pd
Thermal Performance through Heat Retention in Integrated Collector-Storage Solar Water Heaters: A Review
Solar thermal systems are a long-standing technology that is receiving increased attention, in terms of research and development, due to ambitious climate change targets and the need for renewable energy solutions. Integrated collector-storage solar water heaters (ICSSWHs) are a potential contributing solution and numerous studies have focussed on the optimisation of their thermal performance and efficiency. A major drawback of these systems is the heavy heat losses experienced during non-collection periods. To combat this, various heat retention strategies have been proposed and evaluated, including baffles plates, additional insulation, multiple glazing layers, selective coatings, and phase change materials. This paper aims to bring together these studies through a systematic review of the existing literature surrounding the performance of ICSSWH systems, focusing on heat retention. This review provides a comprehensive and up-to-date point of reference on relevant research and developments for researchers in this field
Depression, antidepressant medications, and risk of Clostridium difficile infection
Abstract
Background
An ancillary finding in previous research has suggested that the use of antidepressant medications increases the risk of developing Clostridium difficile infection (CDI). Our objective was to evaluate whether depression or the use of anti-depressants altered the risk of developing CDI, using two distinct datasets and study designs.
Methods
In Study 1, we conducted a longitudinal investigation of a nationally representative sample of older Americans (n = 16,781), linking data from biennial interviews to physician and emergency department visits, stays in hospital and skilled nursing facilities, home health visits, and other outpatient visits. In Study 2, we completed a clinical investigation of hospitalized adults who were tested for C. difficile (n = 4047), with cases testing positive and controls testing negative. Antidepressant medication use prior to testing was ascertained.
Results
The population-based rate of CDI in older Americans was 282.9/100,000 person-years (95% confidence interval (CI)) 226.3 to 339.5) for individuals with depression and 197.1/100,000 person-years for those without depression (95% CI 168.0 to 226.1). The odds of CDI were 36% greater in persons with major depression (95% CI 1.06 to 1.74), 35% greater in individuals with depressive disorders (95% CI 1.05 to 1.73), 54% greater in those who were widowed (95% CI 1.21 to 1.95), and 25% lower in adults who did not live alone (95% CI 0.62 to 0.92). Self-reports of feeling sad or having emotional, nervous or psychiatric problems at baseline were also associated with the later development of CDI. Use of certain antidepressant medications during hospitalization was associated with altered risk of CDI.
Conclusions
Adults with depression and who take specific anti-depressants seem to be more likely to develop CDI. Older adults who are widowed or who live alone are also at greater risk of CDI.http://deepblue.lib.umich.edu/bitstream/2027.42/112859/1/12916_2012_Article_763.pd
Geometry-dependent critical currents in superconducting nanocircuits
In this paper we calculate the critical currents in thin superconducting
strips with sharp right-angle turns, 180-degree turnarounds, and more
complicated geometries, where all the line widths are much smaller than the
Pearl length . We define the critical current as the
current that reduces the Gibbs free-energy barrier to zero. We show that
current crowding, which occurs whenever the current rounds a sharp turn, tends
to reduce the critical current, but we also show that when the radius of
curvature is less than the coherence length this effect is partially
compensated by a radius-of-curvature effect. We propose several patterns with
rounded corners to avoid critical-current reduction due to current crowding.
These results are relevant to superconducting nanowire single-photon detectors,
where they suggest a means of improving the bias conditions and reducing dark
counts. These results also have relevance to normal-metal nanocircuits, as
these patterns can reduce the electrical resistance, electromigration, and hot
spots caused by nonuniform heating.Comment: 29 pages, 24 figure
Characterization of the near-Earth Asteroid 2002NY40
In August 2002, the near-Earth asteroid 2002 NY40, made its closest approach
to the Earth. This provided an opportunity to study a near-Earth asteroid with
a variety of instruments. Several of the telescopes at the Maui Space
Surveillance System were trained at the asteroid and collected adaptive optics
images, photometry and spectroscopy. Analysis of the imagery reveals the
asteroid is triangular shaped with significant self-shadowing. The photometry
reveals a 20-hour period and the spectroscopy shows that the asteroid is a
Q-type
Whole-life design and resource reuse of a solar water heater in the UK
Passive solar systems are often designed primarily with efficiency in mind, and research efforts are concentrated towards gaining an increase in performance. However, due to the multiple materials used, their manufacturing processes, a lifespan that is usually shorter than that of buildings that these systems are applied to and the waste generated when they have reached the end of their useful life, a more holistic approach to the design and performance of these systems should be adopted. This paper reports on the environmental impact of a unique integrated collector–storage solar water heater design, experimentally tested under Scottish weather conditions, considering circular economy and reuse potential. As such, the material flows and components used are mapped against the life-cycle stages of existing European standards while ensuring an optimal efficiency. End-of-life considerations and design for disassembly and reuse are assessed and discussed. Energy payback times of 4·5 and 4·6 years can be realised for a circular and a linear approach, respectively. Operational carbon dioxide savings, which far outstrip the embodied carbon dioxide, demonstrate carbon dioxide payback times of just 7 months, when replacing an electric system. The results show that a holistic design, which promotes circular economy principles, does not compromise efficiency and economic viabilit
One-dimensional metal-organic framework photonic crystals used as platforms for vapor sorption.
We present the fabrication of one-dimensional photonic crystals (Bragg stacks) based on a microporous metal–organic framework material and mesoporous titanium dioxide. The Bragg stack heterostructures were obtained using two complementary synthesis approaches utilizing the bottom-up assembly of heterogeneous, i.e. two-component photonic crystal multilayer structures. Zeolitic imidazolate framework ZIF-8 and mesoporous titanium dioxide were chosen as functional components with different refractive indices. While ZIF-8 is intended to impart molecular selectivity, mesoporous TiO2 is used to ensure high refractive index contrast and to guarantee molecular diffusion within the Bragg stack. The combination of micro- and mesoporosity within one scaffold endows the 1D-MOF PC with characteristic adsorption properties upon exposure to various organic vapors. In this context, the sorption behavior of the photonic material was studied as a function of partial pressure of organic vapors. The results show that the multilayered photonic heterostructures are sensitive and selective towards a series of chemically similar solvent vapors. It is thus anticipated that the concept of multilayer heterogeneous photonic structures will provide a versatile platform for future selective, label-free optical sensors
Na V 1.6a is required for normal activation of motor circuits normally excited by tactile stimulation
A screen for zebrafish motor mutants identified two noncomplementing alleles of a recessive mutation that were named non-active ( nav mi89 and nav mi130 ). nav embryos displayed diminished spontaneous and touch-evoked escape behaviors during the first 3 days of development. Genetic mapping identified the gene encoding Na V 1.6a ( scn8aa ) as a potential candidate for nav . Subsequent cloning of scn8aa from the two alleles of nav uncovered two missense mutations in Na V 1.6a that eliminated channel activity when assayed heterologously. Furthermore, the injection of RNA encoding wild-type scn8aa rescued the nav mutant phenotype indicating that scn8aa was the causative gene of nav . In-vivo electrophysiological analysis of the touch-evoked escape circuit indicated that voltage-dependent inward current was decreased in mechanosensory neurons in mutants, but they were able to fire action potentials. Furthermore, tactile stimulation of mutants activated some neurons downstream of mechanosensory neurons but failed to activate the swim locomotor circuit in accord with the behavioral response of initial escape contractions but no swimming. Thus, mutant mechanosensory neurons appeared to respond to tactile stimulation but failed to initiate swimming. Interestingly fictive swimming could be initiated pharmacologically suggesting that a swim circuit was present in mutants. These results suggested that Na V 1.6a was required for touch-induced activation of the swim locomotor network. © 2010 Wiley Periodicals, Inc. Develop Neurobiol 70:508–522, 2010Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75774/1/20791_ftp.pd
Etude morphostructurale de la zone sud des rides Nouvelle-Calédonie et Loyauté (Zone Economique Exclusive de Nouvelle-Calédonie, Pacifique Sud-Ouest)
Les données de la campagne ZoNéCo 1 permettent de préciser la morphostructure du Sud des rides calédonienne et Loyauté qui s'avèrent plus complexes que les cartes précédentes ne le montraient, mais on retrouve les principales structures de la région Calédonie-Loyauté. L'imagerie met en évidence les zones de roches nues ou encroûtées, la présence d'écoulements gravitaires du Sud du bassin des Loyauté vers le bassin Sud-Fidjien. (Résumé d'auteur
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