1,949 research outputs found

    Jupiter’s equatorial X-ray emissions over two solar cycles

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    Jupiter’s disk is bright in X-rays as H2 molecules in the atmosphere are very effective at scattering solar X-rays. K-shell fluorescence from carbon atoms in atmospheric methane is thought to also provide a minor contribution. XMM-Newton has now observed Jupiter over a span of nearly two solar cycles from 2003 to 2021, offering the opportunity to determine whether Jupiter’s disk emissions are driven by solar activity or not. We compare the count rates of X-rays of energies 0.2–10.0 keV, 0.2–2.0 keV, 2.1–5.0 keV, and 5.1–10.0 keV from the planet’s equatorial region, with the sunspot number and F10.7 adjusted solar radio flux. The respective Pearson’s Correlation Coefficients for both are 0.88/0.84, 0.86/0.83, 0.40/0.34 and 0.29/0.22 for each energy demonstrating that the low energy X-ray disk emissions are indeed controlled by the Sun’s activity. This relationship is less clear for the higher energy emissions, raising questions around the source of these emissions

    A Planar CMOS Field-Emission Vacuum Magnetic Sensor

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    We have fabricated a CMOS vacuum magnetic sensor that exploits the deflection of an electron beam produced by field emission by a perpendicular magnetic field. The device is planar and fabricated by conventional lithography and etching processes. An extremely high magnetic field sensitivity of 4 x 10(3)%/T is reported

    Augmenting the 6-3-5 method with design information

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    This paper describes a comparative study between the 6-3-5 Method and the ICR Grid. The ICR Grid is an evolved variant of 6-3-5 intended to better integrate information into the concept generation process. Unlike a conventional 6-3-5 process where participants continually sketch concepts, using the ICR Grid (the name derived from its Inform, Create, Reflect activities and structured, grid-like output) participants are additionally required to undertake information search tasks, use specific information items for concept development, and reflect on the merit of concepts as the session progresses. The results indicate that although the quantity of concepts was lower, the use of information had a positive effect in a number of areas, principally the quality and variety of output. Although grounded in the area of product development, this research is applicable to any organisation undertaking idea generation and problem solving. As well as providing insights on the transference of information to concepts, it holds additional interest for studies on the composition and use of digital libraries

    Clinical predictors of rectal lymphogranuloma venereum infection: results from a multicentre case-control study in the UK

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    Objective: Since 2003, over 2000 cases of lymphogranuloma venereum (LGV) have been diagnosed in the UK in men who have sex with men (MSM). Most cases present with proctitis, but there are limited data on how to differentiate clinically between LGV and other pathology. We analysed the clinical presentations of rectal LGV in MSM to identify clinical characteristics predictive of LGV proctitis and produced a clinical prediction model. Design: A prospective multicentre case–control study was conducted at six UK hospitals from 2008 to 2010. Cases of rectal LGV were compared with controls with rectal symptoms but without LGV. Methods: Data from 98 LGV cases and 81 controls were collected from patients and clinicians using computer-assisted self-interviews and clinical report forms. Univariate and multivariate logistic regression was used to compare symptoms and signs. Clinical prediction models for LGV were compared using receiver operating curves. Results: Tenesmus, constipation, anal discharge and weight loss were significantly more common in cases than controls. In multivariate analysis, tenesmus and constipation alone were suggestive of LGV (OR 2.98, 95% CI 0.99 to 8.98 and 2.87, 95% CI 1.01 to 8.15, respectively) and that tenesmus alone or in combination with constipation was a significant predictor of LGV (OR 6.97, 95% CI 2.71 to 17.92). The best clinical prediction was having one or more of tenesmus, constipation and exudate on proctoscopy, with a sensitivity of 77% and specificity of 65%. Conclusions: This study indicates that tenesmus alone or in combination with constipation makes a diagnosis of LGV in MSM presenting with rectal symptoms more likely

    Rings in the Solar System: a short review

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    Rings are ubiquitous around giant planets in our Solar System. They evolve jointly with the nearby satellite system. They could form either during the giant planet formation process or much later, as a result of large scale dynamical instabilities either in the local satellite system, or at the planetary scale. We review here the main characteristics of rings in our solar system, and discuss their main evolution processes and possible origin. We also discuss the recent discovery of rings around small bodies.Comment: Accepted for the Handbook of Exoplanet

    Observed Reductions in Schistosoma mansoni Transmission from Large-Scale Administration of Praziquantel in Uganda: A Mathematical Modelling Study

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    To date schistosomiasis control programmes based on chemotherapy have largely aimed at controlling morbidity in treated individuals rather than at suppressing transmission. In this study, a mathematical modelling approach was used to estimate reductions in the rate of Schistosoma mansoni reinfection following annual mass drug administration (MDA) with praziquantel in Uganda over four years (2003-2006). In doing this we aim to elucidate the benefits of MDA in reducing community transmission.Age-structured models were fitted to a longitudinal cohort followed up across successive rounds of annual treatment for four years (Baseline: 2003, TREATMENT: 2004-2006; n = 1,764). Instead of modelling contamination, infection and immunity processes separately, these functions were combined in order to estimate a composite force of infection (FOI), i.e., the rate of parasite acquisition by hosts.MDA achieved substantial and statistically significant reductions in the FOI following one round of treatment in areas of low baseline infection intensity, and following two rounds in areas with high and medium intensities. In all areas, the FOI remained suppressed following a third round of treatment.This study represents one of the first attempts to monitor reductions in the FOI within a large-scale MDA schistosomiasis morbidity control programme in sub-Saharan Africa. The results indicate that the Schistosomiasis Control Initiative, as a model for other MDA programmes, is likely exerting a significant ancillary impact on reducing transmission within the community, and may provide health benefits to those who do not receive treatment. The results obtained will have implications for evaluating the cost-effectiveness of schistosomiasis control programmes and the design of monitoring and evaluation approaches in general

    Can spacetime curvature induced corrections to Lamb shift be observable?

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    The Lamb shift results from the coupling of an atom to vacuum fluctuations of quantum fields, so corrections are expected to arise when the spacetime is curved since the vacuum fluctuations are modified by the presence of spacetime curvature. Here, we calculate the curvature-induced correction to the Lamb shift outside a spherically symmetric object and demonstrate that this correction can be remarkably significant outside a compact massive astrophysical body. For instance, for a neutron star or a stellar mass black hole, the correction is \sim 25% at a radial distance of 4GM/c24GM/c^2, \sim 16% at 10GM/c210GM/c^2 and as large as \sim 1.6% even at 100GM/c2100GM/c^2, where MM is the mass of the object, GG the Newtonian constant, and cc the speed of light. In principle, we can look at the spectra from a distant compact super-massive body to find such corrections. Therefore, our results suggest a possible way of detecting fundamental quantum effects in astronomical observations.Comment: 13 pages, 3 figures, slight title change, clarifications and more discussions added, version to be published in JHE
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