3,257 research outputs found

    Designing Primary Prevention for People Living with HIV

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    Today, there are new reasons for a sharper focus on prevention for people living with HIV. Growing numbers of people with the disease are living more healthy, sexual lives. Recent evidence suggests that risk taking among both HIV-positive and negative people is increasing. After nearly two decades of life in the shadow of AIDS, communities are growing weary of traditional prevention messages and many people are openly grappling with difficult questions of intimacy and sex. Increasingly, people living with HIV also face multiple complex economic and substance abuse challenges that complicate prevention efforts.There is an urgent need -- and sufficient expertise -- to move forward with prevention campaigns focused on helping people living with HIV and AIDS avoid passing their infection along to others. Numerous innovative interventions for people with HIV show promise, including:a social marketing campaign for gay men and a five-session group intervention for women living with HIV in Massachusetts,a chat line for positives and a group session program for Latinas/Latinos in Los Angeles,Internet chat room interventions in Atlanta,a group session for gay Asian American-Pacific Islander Americans living with HIV in San Francisco, andPrevention Case Management programs newly funded by the Centers for Disease Control

    ARAS: an automated radioactivity aliquoting system for dispensing solutions containing positron-emitting radioisotopes.

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    BackgroundAutomated protocols for measuring and dispensing solutions containing radioisotopes are essential not only for providing a safe environment for radiation workers but also to ensure accuracy of dispensed radioactivity and an efficient workflow. For this purpose, we have designed ARAS, an automated radioactivity aliquoting system for dispensing solutions containing positron-emitting radioisotopes with particular focus on fluorine-18 ((18)F).MethodsThe key to the system is the combination of a radiation detector measuring radioactivity concentration, in line with a peristaltic pump dispensing known volumes.ResultsThe combined system demonstrates volume variation to be within 5 % for dispensing volumes of 20 μL or greater. When considering volumes of 20 μL or greater, the delivered radioactivity is in agreement with the requested amount as measured independently with a dose calibrator to within 2 % on average.ConclusionsThe integration of the detector and pump in an in-line system leads to a flexible and compact approach that can accurately dispense solutions containing radioactivity concentrations ranging from the high values typical of [(18)F]fluoride directly produced from a cyclotron (~0.1-1 mCi μL(-1)) to the low values typical of batches of [(18)F]fluoride-labeled radiotracers intended for preclinical mouse scans (~1-10 μCi μL(-1))

    Discovery of active enhancers through bidirectional expression of short transcripts

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    Abstract Background Long-range regulatory elements, such as enhancers, exert substantial control over tissue-specific gene expression patterns. Genome-wide discovery of functional enhancers in different cell types is important for our understanding of genome function as well as human disease etiology. Results In this study, we developed an in silico approach to model the previously reported phenomenon of transcriptional pausing, accompanied by divergent transcription, at active promoters. We then used this model for large-scale prediction of non-promoter-associated bidirectional expression of short transcripts. Our predictions were significantly enriched for DNase hypersensitive sites, histone H3 lysine 27 acetylation (H3K27ac), and other chromatin marks associated with active rather than poised or repressed enhancers. We also detected modest bidirectional expression at binding sites of the CCCTC-factor (CTCF) genome-wide, particularly those that overlap H3K27ac. Conclusions Our findings indicate that the signature of bidirectional expression of short transcripts, learned from promoter-proximal transcriptional pausing, can be used to predict active long-range regulatory elements genome-wide, likely due in part to specific association of RNA polymerase with enhancer regions

    Surface Distributions for Eddy Current Probes

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    This paper is concerned with the computation of the thin-skin solution for eddy current distributions induced in the presence of surface breaking flaws. Earlier work [1], [2], [3], [4] dealt with cases where the distribution induced in the absence of a flaw was uniform. An unfolding technique was developed which reduced the determination of the surface field to a classical two-dimensional potential problem. Exact solutions were obtained by complex potential methods for circular-arc cracks in [1], [2] and for rectangular and triangular cracks in [3], but the main focus of attention in this last work was on semi-elliptical cracks since it is found in practice that many surface fatigue cracks grow with a plan form which can be closely approximated by a half ellipse. This case was not amenable to exact treatment, but the introduction of elliptic co-ordinates allowed a Fourier series solution to be calculated

    RNase MRP and the RNA processing cascade in the eukaryotic ancestor

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    BACKGROUND: Within eukaryotes there is a complex cascade of RNA-based macromolecules that process other RNA molecules, especially mRNA, tRNA and rRNA. An example is RNase MRP processing ribosomal RNA (rRNA) in ribosome biogenesis. One hypothesis is that this complexity was present early in eukaryotic evolution; an alternative is that an initial simpler network later gained complexity by gene duplication in lineages that led to animals, fungi and plants. Recently there has been a rapid increase in support for the complexity-early theory because the vast majority of these RNA-processing reactions are found throughout eukaryotes, and thus were likely to be present in the last common ancestor of living eukaryotes, herein called the Eukaryotic Ancestor. RESULTS: We present an overview of the RNA processing cascade in the Eukaryotic Ancestor and investigate in particular, RNase MRP which was previously thought to have evolved later in eukaryotes due to its apparent limited distribution in fungi and animals and plants. Recent publications, as well as our own genomic searches, find previously unknown RNase MRP RNAs, indicating that RNase MRP has a wide distribution in eukaryotes. Combining secondary structure and promoter region analysis of RNAs for RNase MRP, along with analysis of the target substrate (rRNA), allows us to discuss this distribution in the light of eukaryotic evolution. CONCLUSION: We conclude that RNase MRP can now be placed in the RNA-processing cascade of the Eukaryotic Ancestor, highlighting the complexity of RNA-processing in early eukaryotes. Promoter analyses of MRP-RNA suggest that regulation of the critical processes of rRNA cleavage can vary, showing that even these key cellular processes (for which we expect high conservation) show some species-specific variability. We present our consensus MRP-RNA secondary structure as a useful model for further searches

    Will web-based research suffice when collecting U.S. school district policies? The case of physical education and school-based nutrition policies

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    <p>Abstract</p> <p>Background</p> <p>Recognizing the growing childhood overweight problem, a number of school-based strategies, including policy approaches, have been proposed and are being implemented to address the problem considering the amount of time children spend in schools. This paper describes the results of a pilot study that tested approaches to collecting U.S. school district policy information regarding physical education and nutrition requirements that can inform efforts by policy makers, researchers, advocates and others interested in collecting school district-level obesity-related policies that are typically not systematically available from a "one stop" source.</p> <p>Methods</p> <p>Sixty local school districts representing six states were selected for conducting the district policy research, with larger, urban school districts over-sampled to facilitate collection of policies from districts representing a larger proportion of the public school population in each study state. The six states within which the pilot districts were located were chosen based on the variability in their physical education and school-based nutrition policy and geographic and demographic diversity. Web research and a mail canvass of the study districts was conducted between January and May 2006 to obtain all relevant policies. An additional field collection effort was conducted in a sample of districts located in three study states to test the extent to which field collection would yield additional information.</p> <p>Results</p> <p>Policies were obtained from 40 (67%) of the 60 districts, with policies retrieved via both Web and mail canvass methods in 16 (27%) of the districts, and were confirmed to not exist in 10 (17%) of the districts. Policies were more likely to be retrieved from larger, urban districts, whereas the smallest districts had no policies available on the Web. In no instances were exactly the same policies retrieved from the two sources. Physical education policies were slightly more prevalent than nutrition policies.</p> <p>Conclusion</p> <p>Collection of U.S. local school district policies requires a multi-pronged approach. Web research and mail canvasses will likely yield different types of policy information. Given the variance in district-level Web site presence, researchers and others interested in obtaining district physical education and nutrition-related policies should consider supplementing Web research with more direct methods.</p

    A kinematic study of the Andromeda dwarf spheroidal system

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    We present a homogeneous kinematic analysis of red giant branch stars within 18 of the 28 Andromeda dwarf spheroidal (dSph) galaxies, obtained using the Keck I LRIS and Keck II DEIMOS spectrographs. Based on their g-i colors (taken with the CFHT MegaCam imager), physical positions on the sky, and radial velocities, we assign probabilities of dSph membership to each observed star. Using this information, the velocity dispersions, central masses and central densities of the dark matter halos are calculated for these objects, and compared with the properties of the Milky Way dSph population. We also measure the average metallicity ([Fe/H]) from the co-added spectra of member stars for each M31 dSph and find that they are consistent with the trend of decreasing [Fe/H] with luminosity observed in the Milky Way population. We find that three of our studied M31 dSphs appear as significant outliers in terms of their central velocity dispersion, And XIX, XXI and XXV, all of which have large half-light radii (>700 pc) and low velocity dispersions (sigma_v<5 km/s). In addition, And XXV has a mass-to-light ratio within its half-light radius of just [M/L]_{half}=10.3^{+7.0}_{-6.7}, making it consistent with a simple stellar system with no appreciable dark matter component within its 1 sigma uncertainties. We suggest that the structure of the dark matter halos of these outliers have been significantly altered by tides.Comment: 41 pages, 23 figures. Accepted for publication in Ap

    Recent Decisions

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    Comments on recent decisions by Cornelius F. Collins, Joseph P. Summers, Michael E. Phenner, Daniel J. Manelli, Ralph H. Witt, Richard C. Wilbur, and Raymond W. Brown

    Schmallenberg virus: a systematic international literature review (2011-2019) from an Irish perspective

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    peer-reviewedIn Autumn 2011, nonspecific clinical signs of pyrexia, diarrhoea, and drop in milk yield were observed in dairy cattle near the German town of Schmallenberg at the Dutch/German border. Targeted veterinary diagnostic investigations for classical endemic and emerging viruses could not identify a causal agent. Blood samples were collected from animals with clinical signs and subjected to metagenomic analysis; a novel orthobunyavirus was identified and named Schmallenberg virus (SBV). In late 2011/early 2012, an epidemic of abortions and congenital malformations in calves, lambs and goat kids, characterised by arthrogryposis and hydranencephaly were reported in continental Europe. Subsequently, SBV RNA was confirmed in both aborted and congenitally malformed foetuses and also in Culicoides species biting midges. It soon became evident that SBV was an arthropod-borne teratogenic virus affecting domestic ruminants. SBV rapidly achieved a pan-European distribution with most countries confirming SBV infection within a year or two of the initial emergence. The first Irish case of SBV was confirmed in the south of the country in late 2012 in a bovine foetus. Since SBV was first identified in 2011, a considerable body of scientific research has been conducted internationally describing this novel emerging virus. The aim of this systematic review is to provide a comprehensive synopsis of the most up-to-date scientific literature regarding the origin of SBV and the spread of the Schmallenberg epidemic, in addition to describing the species affected, clinical signs, pathogenesis, transmission, risk factors, impact, diagnostics, surveillance methods and control measures. This review also highlights current knowledge gaps in the scientific literature regarding SBV, most notably the requirement for further research to determine if, and to what extent, SBV circulation occurred in Europe and internationally during 2017 and 2018. Moreover, recommendations are also made regarding future arbovirus surveillance in Europe, specifically the establishment of a European-wide sentinel herd surveillance program, which incorporates bovine serology and Culicoides entomology and virology studies, at national and international level to monitor for the emergence and re-emergence of arboviruses such as SBV, bluetongue virus and other novel Culicoides-borne arboviruses
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