507 research outputs found

    First report of clinical presentation of a bite by a running spider, Philodromus sp. (Araneae: Philodromidae), with recommendations for spider bite management

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    This article describes the clinical progression of symptoms over a period of 5 days of a bite inflicted by a Philodromus sp. spider. Commonly known as ‘running spiders’, these are not considered to be harmful to humans. This report, however, is the first description of an actual bite by a member of this group of spiders showing cytotoxic envenomation. Management of the bites should be as recommended for other cytotoxic spider bites.http://www.samj.org.zaam2017Zoology and Entomolog

    Testing the Void against Cosmological data: fitting CMB, BAO, SN and H0

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    In this paper, instead of invoking Dark Energy, we try and fit various cosmological observations with a large Gpc scale under-dense region (Void) which is modeled by a Lemaitre-Tolman-Bondi metric that at large distances becomes a homogeneous FLRW metric. We improve on previous analyses by allowing for nonzero overall curvature, accurately computing the distance to the last-scattering surface and the observed scale of the Baryon Acoustic peaks, and investigating important effects that could arise from having nontrivial Void density profiles. We mainly focus on the WMAP 7-yr data (TT and TE), Supernova data (SDSS SN), Hubble constant measurements (HST) and Baryon Acoustic Oscillation data (SDSS and LRG). We find that the inclusion of a nonzero overall curvature drastically improves the goodness of fit of the Void model, bringing it very close to that of a homogeneous universe containing Dark Energy, while by varying the profile one can increase the value of the local Hubble parameter which has been a challenge for these models. We also try to gauge how well our model can fit the large-scale-structure data, but a comprehensive analysis will require the knowledge of perturbations on LTB metrics. The model is consistent with the CMB dipole if the observer is about 15 Mpc off the centre of the Void. Remarkably, such an off-center position may be able to account for the recent anomalous measurements of a large bulk flow from kSZ data. Finally we provide several analytical approximations in different regimes for the LTB metric, and a numerical module for CosmoMC, thus allowing for a MCMC exploration of the full parameter space.Comment: 70 pages, 12 figures, matches version accepted for publication in JCAP. References added, numerical values in tables changed due to minor bug, conclusions unaltered. Numerical module available at http://web.physik.rwth-aachen.de/download/valkenburg

    Combating HIV stigma in low- and middle-income healthcare settings: a scoping review

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    Introduction: Nearly 40 years into the HIV epidemic, the persistence of HIV stigma is a matter of grave urgency. Discrimination (i.e. enacted stigma) in healthcare settings is particularly problematic as it deprives people of critical healthcare services while also discouraging preventive care seeking by confirming fears of anticipated stigma. We review existing research on the effectiveness of stigma interventions in healthcare settings of low- and middle-income countries (LMIC), where stigma control efforts are often further complicated by heavy HIV burdens, less developed healthcare systems, and the layering of HIV stigma with discrimination towards other marginalized identities. This review describes progress in this field to date and identifies research gaps to guide future directions for research. Methods: We conducted a scoping review of HIV reduction interventions in LMIC healthcare settings using Embase, Ovid MEDLINE, PsycINFO and Scopus (through March 5, 2020). Information regarding study design, stigma measurement techniques, intervention features and study findings were extracted. We also assessed methodological rigor using the Joanna Briggs Institute checklist for systematic reviews. Results and discussion: Our search identified 8766 studies, of which 19 were included in the final analysis. All but one study reported reductions in stigma following the intervention. The studies demonstrated broad regional distribution across LMIC and many employed designs that made use of a control condition. However, these strengths masked key shortcomings including a dearth of research from the lowest income category of LMIC and a lack of interventions to address institutional or structural determinants of stigma. Lastly, despite the fact that most stigma measures were based on existing instruments, only three studies described steps taken to validate or adapt the stigma measures to local settings. Conclusions: Combating healthcare stigma in LMIC demands interventions that can simultaneously address resource constraints, high HIV burden and more severe stigma. Our findings suggest that this will require more objective, reliable and culturally adaptable stigma measures to facilitate meaningful programme evaluation and comparison across studies. All but one study concluded that their interventions were effective in reducing healthcare stigma. Though encouraging, the fact that most studies measured impact using self-reported measures suggests that social desirability may bias results upwards. Homogeneity of study results also hindered our ability to draw substantive conclusions about potential best practices to guide the design of future stigma reduction programmes

    Reduced meiotic recombination on the XY bivalent is correlated with an increased incidence of sex chromosome aneuploidy in men with non-obstructive azoospermia

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    Both aberrant meiotic recombination and an increased frequency of sperm aneuploidy have been observed in infertile men. However, this association has not been demonstrated within individual men. The purpose of this study was to determine the association between the frequency of recombination observed in pachytene spermatocytes and the frequency of aneuploidy in sperm from the same infertile men. Testicular tissue from seven men with non-obstructive azoospermia (NOA) and six men undergoing vasectomy reversal (controls) underwent meiotic analysis. Recombination sites were recorded for individual chromosomes. Testicular and ejaculated sperm from NOA patients and controls, respectively, were tested for aneuploidy frequencies for chromosomes 9, 21, X and Y. There was a significant increase in the frequency of pachytene cells with at least one achiasmate bivalent in infertile men (12.4%) compared with controls (4.2%, P = 0.02). Infertile men also had a significantly higher frequency of sperm disomy than controls for chromosomes 21 (1.0% versus 0.24%, P = 0.001), XX (0.16% versus 0.03%, P = 0.004) and YY (0.12% versus 0.03%, P = 0.04). There was a significant correlation between meiotic cells with zero MLH1 foci in the sex body and total sex chromosome disomy (XX + YY + XY) in sperm from men with NOA (r = 0.79, P = 0.036)

    Optimization of the Strength-Fracture Toughness Relation in Particulate-Reinforced Aluminum Composites via Control of the Matrix Microstructure

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    The article of record as published may be found at http://dx.doi.org/10.1007/s11661-998-0119-9The evolution of the microstructure and mechanical properties of a 17.5 vol. pct SiC particulatereinforced aluminum alloy 6092-matrix composite has been studied as a function of postfabrication processing and heat treatment. It is demonstrated that, by the control of particulate distribution, matrix grain, and substructure and of the matrix precipitate state, the strength-toughness combination in the composite can be optimized over a wide range of properties, without resorting to unstable, underaged (UA) matrix microstructures, which are usually deemed necessary to produce a higher fracture toughness than that displayed in the peak-aged condition. Further, it is demonstrated that, following an appropriate combination of thermomechanical processing and unconventional heat treatment, the composite may possess better stiffness, strength, and fracture toughness than a similar unreinforced alloy. In the high- and low-strength matrix microstructural conditions, the matrix grain and substructure were found to play a substantial role in determining fracture properties. However, in the intermediate- strength regime, properties appeared to be optimizable by the utilization of heat treatments only. These observations are rationalized on the basis of current understanding of the grain size dependence of fracture toughness and the detailed microstructural features resulting from thermomechanical treatments.United States Army Research OfficeArmy Research LabratoryUnited States Air Force Office of Scientific ResearchWright Materials LabratoryDWA Composite
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