281 research outputs found

    The Thousand Asteroid Light Curve Survey

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    We present the results of our Thousand Asteroid Light Curve Survey (TALCS) conducted with the Canada-France-Hawaii Telescope in September 2006. Our untargeted survey detected 828 Main Belt asteroids to a limiting magnitude of g'~22.5 corresponding to a diameter range of 0.4 km <= D <= 10 km. Of these, 278 objects had photometry of sufficient quality to perform rotation period fits. We debiased the observations and light curve fitting process to determine the true distribution of rotation periods and light curve amplitudes of Main Belt asteroids. We confirm a previously reported excess in the fraction of fast rotators but find a much larger excess of slow rotating asteroids (~15% of our sample). A few percent of objects in the TALCS size range have large light curve amplitudes of ~1 mag. Fits to the debiased distribution of light curve amplitudes indicate that the distribution of triaxial ellipsoid asteroid shapes is proportional to the square of the axis-ratio, (b/a)^2, and may be bi-modal. Finally, we find six objects with rotation periods that may be less than 2 hours with diameters between 400 m and 1.5 km, well above the break-up limit for a gravitationally-bound aggregate. Our debiased data indicate that this population represents <4% of the Main Belt in the 1-10 km size range.Comment: Accepted to Icarus. Full tables to appear there in electronic format, or contact autho

    Measurement and Reproducibility of Preserved Ellipsoid Zone Area and Preserved Retinal Pigment Epithelium Area in Eyes With Choroideremia

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    PURPOSE: To identify valid and reproducible methods for quantifying anatomic outcome measures for eyes with choroideremia (CHM) in clinical trials. DESIGN: Reliability analysis study. METHODS: In this multicenter study, patients with confirmed genetic diagnosis of CHM were enrolled. All cases underwent spectral-domain optical coherence tomography (SDOCT) and fundus autofluorescence (FAF) imaging. Two graders independently delineated boundaries of preserved autofluorescence (PAF) and pre-served ellipsoid zone (EZ) on FAF and OCT images, respectively. The results of the 2 independent gradings of both FAF and OCT images were compared to assess the reproducibility of the grading methods. RESULTS: A total of 148 eyes from 75 cases were included. In 21% of eyes PAF and in 43% of eyes preserved EZ had extended beyond the image capture area. After exclusion of these eyes and low-quality images, 114 FAF and 77 OCT images were graded. The mean PAF areas from 2 independent gradings were 3.720 +/- 3.340 mm(2) and 3.692 +/- 3.253 mm2, respectively. Intraclass correlation coefficient (ICC) for these gradings was 0.996. The mean preserved EZ areas from 2 independent gradings were 2.746 +/- 2.319 mm2 and 2.858 2.446 mm2, respectively. ICC for these gradings was 0.991. CONCLUSIONS: Quantifying preserved retinal pigment epithelium and EZ areas on FAF and OCT images, respectively, in CHM patients is highly reproducible. These variables would be potential anatomic outcome measures for CHM clinical trials and could be studied and tracked longitudinally in choroideremia. (C) 2017 Elsevier Inc. All rights reserved.Peer reviewe

    Heliophysics and Amateur Radio:Citizen Science Collaborations for Atmospheric, Ionospheric, and Space Physics Research and Operations

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    The amateur radio community is a global, highly engaged, and technical community with an intense interest in space weather, its underlying physics, and how it impacts radio communications. The large-scale observational capabilities of distributed instrumentation fielded by amateur radio operators and radio science enthusiasts offers a tremendous opportunity to advance the fields of heliophysics, radio science, and space weather. Well-established amateur radio networks like the RBN, WSPRNet, and PSKReporter already provide rich, ever-growing, long-term data of bottomside ionospheric observations. Up-and-coming purpose-built citizen science networks, and their associated novel instruments, offer opportunities for citizen scientists, professional researchers, and industry to field networks for specific science questions and operational needs. Here, we discuss the scientific and technical capabilities of the global amateur radio community, review methods of collaboration between the amateur radio and professional scientific community, and review recent peer-reviewed studies that have made use of amateur radio data and methods. Finally, we present recommendations submitted to the U.S. National Academy of Science Decadal Survey for Solar and Space Physics (Heliophysics) 2024–2033 for using amateur radio to further advance heliophysics and for fostering deeper collaborations between the professional science and amateur radio communities. Technical recommendations include increasing support for distributed instrumentation fielded by amateur radio operators and citizen scientists, developing novel transmissions of RF signals that can be used in citizen science experiments, developing new amateur radio modes that simultaneously allow for communications and ionospheric sounding, and formally incorporating the amateur radio community and its observational assets into the Space Weather R2O2R framework. Collaborative recommendations include allocating resources for amateur radio citizen science research projects and activities, developing amateur radio research and educational activities in collaboration with leading organizations within the amateur radio community, facilitating communication and collegiality between professional researchers and amateurs, ensuring that proposed projects are of a mutual benefit to both the professional research and amateur radio communities, and working towards diverse, equitable, and inclusive communities

    Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

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    BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

    A comparative genomics study of 23 Aspergillus species from section Flavi

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    Section Flavi encompasses both harmful and beneficial Aspergillus species, such as Aspergillus oryzae, used in food fermentation and enzyme production, and Aspergillus flavus, food spoiler and mycotoxin producer. Here, we sequence 19 genomes spanning section Flavi and compare 31 fungal genomes including 23 Flavi species. We reassess their phylogenetic relationships and show that the closest relative of A. oryzae is not A. flavus, but A. minisclerotigenes or A. aflatoxiformans and identify high genome diversity, especially in sub-telomeric regions. We predict abundant CAZymes (598 per species) and prolific secondary metabolite gene clusters (73 per species) in section Flavi. However, the observed phenotypes (growth characteristics, polysaccharide degradation) do not necessarily correlate with inferences made from the predicted CAZyme content. Our work, including genomic analyses, phenotypic assays, and identification of secondary metabolites, highlights the genetic and metabolic diversity within section Flavi.Peer reviewe

    Progressing from multidisciplinary to interdisciplinary restoration science: monitoring and applied studies on the Nisqually River Delta

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    Restoration science is often described as an ultimate test of ecological theory; assessing the value of restoration actions is challenged by difficulties in measuring complex interactions between restored physical processes and the response of biological resources. Yet, demonstrating the value of restoration is a key to sustaining future public investment, especially in light of uncertainty of future climate change effects. At the Nisqually River Delta, a restoration partnership between the U. S. Fish and Wildlife Service Nisqually National Wildlife Refuge (Refuge), the Nisqually Indian Tribe (Tribe), and Ducks Unlimited culminated in re-established tidal flow to 360 ha of historic floodplain and delta representing the largest estuarine restoration in the Pacific Northwest. Restoration of this large delta was expected to result in a substantial improvement in ecological functions and services in southern Puget Sound. The goal of our scientific team, led by the U. S. Geological Survey (USGS) for the project partners, was to assess the biophysical response to restoration. Science objectives were built into a monitoring framework to include hydrodynamics, geomorphology, sedimentation and nearshore processes with vegetation, invertebrate food resources, waterbird, and fisheries. Our science partners included the U. S. Geological Survey, Refuge, Tribe, non-governmental organizations, and universities representing several disciplines. Funding the science was challenging, since as with most wetland restoration projects, adequate funds are rarely included in costs. Instead, the managers and scientists worked together to raise funds through special funds and competitive grants including addressing climate change. With this funding model, a major challenge for the team was communicating and sustaining a vision to make separate multidisciplinary efforts into unified interdisciplinary science. Here, we use lessons learned from early results of the Nisqually River Delta restoration to discuss restoration science in planning processes, funding costs and approaches, monitoring versus applied studies, and advancing interdisciplinary findings from multidisciplinary efforts

    COMPASS identifies T-cell subsets correlated with clinical outcomes.

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    Advances in flow cytometry and other single-cell technologies have enabled high-dimensional, high-throughput measurements of individual cells as well as the interrogation of cell population heterogeneity. However, in many instances, computational tools to analyze the wealth of data generated by these technologies are lacking. Here, we present a computational framework for unbiased combinatorial polyfunctionality analysis of antigen-specific T-cell subsets (COMPASS). COMPASS uses a Bayesian hierarchical framework to model all observed cell subsets and select those most likely to have antigen-specific responses. Cell-subset responses are quantified by posterior probabilities, and human subject-level responses are quantified by two summary statistics that describe the quality of an individual's polyfunctional response and can be correlated directly with clinical outcome. Using three clinical data sets of cytokine production, we demonstrate how COMPASS improves characterization of antigen-specific T cells and reveals cellular 'correlates of protection/immunity' in the RV144 HIV vaccine efficacy trial that are missed by other methods. COMPASS is available as open-source software
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