1,393 research outputs found
Technical Report Series on Global Modeling and Data Assimilation, Volume 41 : GDIS Workshop Report
The workshop "An International Global Drought Information System Workshop: Next Steps" was held on 10-13 December 2014 in Pasadena, California. The more than 60 participants from 15 countries spanned the drought research community and included select representatives from applications communities as well as providers of regional and global drought information products. The workshop was sponsored and supported by the US National Integrated Drought Information System (NIDIS) program, the World Climate Research Program (WCRP: GEWEX, CLIVAR), the World Meteorological Organization (WMO), the Group on Earth Observations (GEO), the European Commission Joint Research Centre (JRC), the US Climate Variability and Predictability (CLIVAR) program, and the US National Oceanic and Atmospheric Administration (NOAA) programs on Modeling, Analysis, Predictions and Projections (MAPP) and Climate Variability & Predictability (CVP). NASA/JPL hosted the workshop with logistical support provided by the GEWEX program office. The goal of the workshop was to build on past Global Drought Information System (GDIS) progress toward developing an experimental global drought information system. Specific goals were threefold: (i) to review recent research results focused on understanding drought mechanisms and their predictability on a wide range of time scales and to identify gaps in understanding that could be addressed by coordinated research; (ii) to help ensure that WRCP research priorities mesh with efforts to build capacity to address drought at the regional level; and (iii) to produce an implementation plan for a short duration pilot project to demonstrate current GDIS capabilities. See http://www.wcrp-climate.org/gdis-wkshp-2014-objectives for more information
Design considerations in a clinical trial of a cognitive behavioural intervention for the management of low back pain in primary care : Back Skills Training Trial
Background
Low back pain (LBP) is a major public health problem. Risk factors for the development and persistence of LBP include physical and psychological factors. However, most research activity has focused on physical solutions including manipulation, exercise training and activity promotion.
Methods/Design
This randomised controlled trial will establish the clinical and cost-effectiveness of a group programme, based on cognitive behavioural principles, for the management of sub-acute and chronic LBP in primary care. Our primary outcomes are disease specific measures of pain and function. Secondary outcomes include back beliefs, generic health related quality of life and resource use. All outcomes are measured over 12 months. Participants randomised to the intervention arm are invited to attend up to six weekly sessions each of 90 minutes; each group has 6–8 participants. A parallel qualitative study will aid the evaluation of the intervention.
Discussion
In this paper we describe the rationale and design of a randomised evaluation of a group based cognitive behavioural intervention for low back pain
Detection of dark galaxies and circum-galactic filaments fluorescently illuminated by a quasar at z=2.4
A deep narrow-band survey for Ly-alpha emission carried out on the VLT-FORS2
has revealed 98 Ly-alpha candidates down to a flux limit of 4.e-18 erg/s/cm^2
in a volume of 5500 comoving Mpc^3 at z=2.4 centered on the hyperluminous
quasar HE0109-3518. The properties of the detected sources in terms of their i)
equivalent width distribution, ii) luminosity function, and iii) the average
luminosity versus projected distance from the quasar, all suggest that a large
fraction of these objects have been fluorescently "illuminated" by HE0109-3518.
This conclusion is supported by comparison with detailed radiative transfer
simulations of the effects of the quasar illumination. 18 objects have a
rest-frame Equivalent Width (EW0) larger than 240A, the expected limit for
Ly-alpha emission powered by Population II star formation and 12 sources among
these do not have any continuum counterpart in a deep V-band imaging of the
same field. For these, a stacking analysis indicates EW0>800A, effectively
ruling out Ly-alpha powered by internal star formation. These sources are thus
the best candidates so far for proto-galactic clouds or "dark" galaxies at
high-redshift, whose existence has recently been suggested by several
theoretical studies. Assuming they are mostly ionized by the quasar radiation,
we estimate that their gas masses would be about 10^9 Msun implying that their
star formation efficiencies (SFE) are less than 1.e-11 yr^-1 several times
below the SFE of the most gas-rich dwarf galaxies locally, and five hundred
times lower than typical massive star-forming galaxies at z~2. We have also
discovered extended, filamentary gas, also likely illuminated by the quasar,
around some of the brightest continuum-detected sources with EW0>240A. This
emission is compatible with the expectations for circum-galactic cold streams
but other origins, including tidal stripping, are also possible.Comment: 26 pages, 16 figures; MNRAS in press (accepted 2012 Jun 15); minor
changes from previous version, typos corrected, references adde
Publisher correction: Genome-wide association of polycystic ovary syndrome implicates alterations in gonadotropin secretion in European ancestry populations.
An amendment to this paper has been published and can be accessed via a link at the top of the paper
Midgut microbiota of the malaria mosquito vector Anopheles gambiae and Interactions with plasmodium falciparum Infection
The susceptibility of Anopheles mosquitoes to Plasmodium infections relies on complex interactions between the insect vector and the malaria parasite. A number of studies have shown that the mosquito innate immune responses play an important role in controlling the malaria infection and that the strength of parasite clearance is under genetic control, but little is known about the influence of environmental factors on the transmission success. We present here evidence that the composition of the vector gut microbiota is one of the major components that determine the outcome of mosquito infections. A. gambiae mosquitoes collected in natural breeding sites from Cameroon were experimentally challenged with a wild P. falciparum isolate, and their gut bacterial content was submitted for pyrosequencing analysis. The meta-taxogenomic approach revealed a broader richness of the midgut bacterial flora than previously described. Unexpectedly, the majority of bacterial species were found in only a small proportion of mosquitoes, and only 20 genera were shared by 80% of individuals. We show that observed differences in gut bacterial flora of adult mosquitoes is a result of breeding in distinct sites, suggesting that the native aquatic source where larvae were grown determines the composition of the midgut microbiota. Importantly, the abundance of Enterobacteriaceae in the mosquito midgut correlates significantly with the Plasmodium infection status. This striking relationship highlights the role of natural gut environment in parasite transmission. Deciphering microbe-pathogen interactions offers new perspectives to control disease transmission.Institut de Recherche pour le Developpement (IRD); French Agence Nationale pour la Recherche [ANR-11-BSV7-009-01]; European Community [242095, 223601]info:eu-repo/semantics/publishedVersio
Affective Correlates of Stimulant Use and Adherence to Anti-retroviral Therapy Among HIV-positive Methamphetamine Users
The use of stimulants has important implications for HIV prevention and care. However, few investigations have examined psychological correlates of substance use and adherence to anti-retroviral therapy (ART) among HIV-positive stimulant users. This cross-sectional investigation examined affective correlates of stimulant use and ART adherence among HIV-positive methamphetamine users. In total, 122 HIV-positive men who have sex with men or transgendered individuals on ART who reported using methamphetamine in the past 30 days were recruited from the community. HIV-specific traumatic stress was consistently and independently associated with more frequent cocaine/crack use (but not with methamphetamine use). Positive affect was independently associated with a decreased likelihood of reporting any injection drug use and an increased likelihood of reporting perfect ART adherence. HIV-specific traumatic stress may be an important determinant of increased cocaine/crack use in this population. Positive affect may increase the likelihood that individuals will refrain from injection drug use and achieve high levels of ART adherence
Exploring types of focused factories in hospital care: a multiple case study
Background: Focusing on specific treatments or diseases is proposed as a way to increase the efficiency of hospital care. The definition of "focus" or "focused factory", however, lacks clarity. Examples in health care literature relate to very different organizations.\ud
Our aim was to explore the application of the focused factory concept in hospital care, including an indication of its performance, resulting in a conceptual framework that can be helpful in further identifying different types of focused factories. Thus contributing to the understanding of the diversity of examples found in the literature. - \ud
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Methods: We conducted a cross-case comparison of four multiple-case studies into hospital care. To cover a broad array of focus, different specialty fields were selected. Each study investigated the organizational context, the degree of focus, and the operational performance. Focus was measured using an instrument translated from industry. Data were collected using both qualitative and quantitative methods and included site visits. A descriptive analysis was performed at the case study and cross-case studies level. - \ud
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Results: The operational performance per specialty field varied considerably, even when cases showed comparable degrees of focus. Cross-case comparison showed three focus domains. The product domain considered specialty based focused factories that treated patients for a single-specialty, but did not pursue a specific strategy nor adapted work-designs or layouts. The process domain considered delivery based focused factories that treated multiple groups of patients and often pursued strategies to improve efficiency and timeliness and adapted work-designs and physical layouts to minimize delays. The product-process domain considered procedure based focused factories that treated a single well-defined group of patients offering one type of treatment. The strategic focusing decisions and the design of the care delivery system appeared especially important for delivery and procedure based focused factories. - \ud
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Conclusions: Focus in hospital care relates to limitations on the patient group treated and the range of services offered. Based on these two dimensions, we identified three types of focused factories: specialty based, delivery based, and procedure based. Focus could lead to better operational performance, but only when clear strategic focusing decisions are made
Strong interface-induced spin-orbit coupling in graphene on WS2
Interfacial interactions allow the electronic properties of graphene to be
modified, as recently demonstrated by the appearance of satellite Dirac cones
in the band structure of graphene on hexagonal boron nitride (hBN) substrates.
Ongoing research strives to explore interfacial interactions in a broader class
of materials in order to engineer targeted electronic properties. Here we show
that at an interface with a tungsten disulfide (WS2) substrate, the strength of
the spin-orbit interaction (SOI) in graphene is very strongly enhanced. The
induced SOI leads to a pronounced low-temperature weak anti-localization (WAL)
effect, from which we determine the spin-relaxation time. We find that
spin-relaxation time in graphene is two-to-three orders of magnitude smaller on
WS2 than on SiO2 or hBN, and that it is comparable to the intervalley
scattering time. To interpret our findings we have performed first-principle
electronic structure calculations, which both confirm that carriers in
graphene-on-WS2 experience a strong SOI and allow us to extract a
spin-dependent low-energy effective Hamiltonian. Our analysis further shows
that the use of WS2 substrates opens a possible new route to access topological
states of matter in graphene-based systems.Comment: Originally submitted version in compliance with editorial guidelines.
Final version with expanded discussion of the relation between theory and
experiments to be published in Nature Communication
The Circumgalactic Medium in Massive Halos
This chapter presents a review of the current state of knowledge on the cool
(T ~ 1e4 K) halo gas content around massive galaxies at z ~ 0.2-2. Over the
last decade, significant progress has been made in characterizing the cool
circumgalactic gas in massive halos of Mh ~ 1e12-1e14 Msun at intermediate
redshifts using absorption spectroscopy. Systematic studies of halo gas around
massive galaxies beyond the nearby universe are made possible by large
spectroscopic samples of galaxies and quasars in public archives. In addition
to accurate and precise constraints for the incidence of cool gas in massive
halos, detailed characterizations of gas kinematics and chemical compositions
around massive quiescent galaxies at z ~ 0.5 have also been obtained. Combining
all available measurements shows that infalling clouds from external sources
are likely the primary source of cool gas detected at d >~ 100 kpc from massive
quiescent galaxies. The origin of the gas closer in is currently less certain,
but SNe Ia driven winds appear to contribute significantly to cool gas found at
d < 100 kpc. In contrast, cool gas observed at d <~ 200 kpc from luminous
quasars appears to be intimately connected to quasar activities on parsec
scales. The observed strong correlation between cool gas covering fraction in
quasar host halos and quasar bolometric luminosity remains a puzzle. Combining
absorption-line studies with spatially-resolved emission measurements of both
gas and galaxies is the necessary next step to address remaining questions.Comment: 29 pages, 7 figures, invited review to appear in "Gas Accretion onto
Galaxies", Astrophysics and Space Science Library, eds. A. Fox & R. Dave, to
be published by Springe
Utility of Multi-Parametric Quantitative Magnetic Resonance Imaging for Characterization and Radiotherapy Response Assessment in Soft-Tissue Sarcomas and Correlation With Histopathology.
Purpose: To evaluate repeatability of quantitative multi-parametric MRI in retroperitoneal sarcomas, assess parameter changes with radiotherapy, and correlate pre-operative values with histopathological findings in the surgical specimens. Materials and Methods: Thirty patients with retroperitoneal sarcoma were imaged at baseline, of whom 27 also underwent a second baseline examination for repeatability assessment. 14/30 patients were treated with pre-operative radiotherapy and were imaged again after completing radiotherapy (50.4 Gy in 28 daily fractions, over 5.5 weeks). The following parameter estimates were assessed in the whole tumor volume at baseline and following radiotherapy: apparent diffusion coefficient (ADC), parameters of the intra-voxel incoherent motion model of diffusion-weighted MRI (D, f, D*), transverse relaxation rate, fat fraction, and enhancing fraction after gadolinium-based contrast injection. Correlation was evaluated between pre-operative quantitative parameters and histopathological assessments of cellularity and fat fraction in post-surgical specimens (ClinicalTrials.gov, registration number NCT01902667). Results: Upper and lower 95% limits of agreement were 7.1 and -6.6%, respectively for median ADC at baseline. Median ADC increased significantly post-radiotherapy. Pre-operative ADC and D were negatively correlated with cellularity (r = -0.42, p = 0.01, 95% confidence interval (CI) -0.22 to -0.59 for ADC; r = -0.45, p = 0.005, 95% CI -0.25 to -0.62 for D), and fat fraction from Dixon MRI showed strong correlation with histopathological assessment of fat fraction (r = 0.79, p = 10-7, 95% CI 0.69-0.86). Conclusion: Fat fraction on MRI corresponded to fat content on histology and therefore contributes to lesion characterization. Measurement repeatability was excellent for ADC; this parameter increased significantly post-radiotherapy even in disease categorized as stable by size criteria, and corresponded to cellularity on histology. ADC can be utilized for characterizing and assessing response in heterogeneous retroperitoneal sarcomas
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