266 research outputs found

    Radio emission from Supernova Remnants

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    The explosion of a supernova releases almost instantaneously about 10^51 ergs of mechanic energy, changing irreversibly the physical and chemical properties of large regions in the galaxies. The stellar ejecta, the nebula resulting from the powerful shock waves, and sometimes a compact stellar remnant, constitute a supernova remnant (SNR). They can radiate their energy across the whole electromagnetic spectrum, but the great majority are radio sources. Almost 70 years after the first detection of radio emission coming from a SNR, great progress has been achieved in the comprehension of their physical characteristics and evolution. We review the present knowledge of different aspects of radio remnants, focusing on sources of the Milky Way and the Magellanic Clouds, where the SNRs can be spatially resolved. We present a brief overview of theoretical background, analyze morphology and polarization properties, and review and critical discuss different methods applied to determine the radio spectrum and distances. The consequences of the interaction between the SNR shocks and the surrounding medium are examined, including the question of whether SNRs can trigger the formation of new stars. Cases of multispectral comparison are presented. A section is devoted to reviewing recent results of radio SNRs in the Magellanic Clouds, with particular emphasis on the radio properties of SN 1987A, an ideal laboratory to investigate dynamical evolution of an SNR in near real time. The review concludes with a summary of issues on radio SNRs that deserve further study, and analyzing the prospects for future research with the latest generation radio telescopes.Comment: Revised version. 48 pages, 15 figure

    Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

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    Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente

    Protein and folic acid content in the maternal diet determine lipid metabolism and response to high-fat feeding in rat progeny in an age-dependent manner

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    Maternal diet during gestation can exert a long-term effect on the progeny’s health by programming their developmental scheme and metabolism. The aim of this study is to analyze the influence of maternal diet on lipid metabolism in 10- and 16-week-old rats. Pregnant dams were fed one of four diets: a normal protein and normal folic acid diet (NP-NF), a protein-restricted and normal folic acid diet (PR-NF), a protein-restricted and folic-acid-supplemented diet (PR-FS), or a normal protein and folic-acid-supplemented diet (NP-FS). We also tested whether prenatal nutrition determines the reaction of an organism to a postweaning high-fat diet. Blood biochemistry and biometrical parameters were evaluated. The expression patterns of PPARα, PPARγ, and LXRα in the liver and adipose tissue were examined by real-time PCR. In the 10-week-old, rats folic acid supplementation of the maternal diet was associated with reduced circulating glucose and total cholesterol concentrations (P < 0.01 and P < 0.001, respectively). Neither prenatal diets nor postnatal feeding affected blood insulin concentrations. In the 16-week-old rats, body weight, abdominal fat mass and central adiposity were reduced in the progeny of the folic acid–supplemented dams (P < 0.01, P < 0.001 and P < 0.01, respectively). Maternal protein restriction had no effect on biometry or blood biochemical parameters. Folic acid supplementation of the maternal diet was associated with reduced expression of PPARα, PPARγ, and LXRα in the liver (P < 0.001). Reduced protein content in the maternal diet was associated with increased PPARα mRNA level in the liver (P < 0.001) and reduced LXRα in adipose tissue (P < 0.01). PPARα and PPARγ transcription in the liver, as well as LXRα transcription in adipose tissue, was also dependent on interaction effects between prenatal and postnatal diet compositions. PPARγ transcription in the liver was correlated with the abdominal fat mass, body weight, and calorie intake, while PPARγ transcription in adipose tissue was correlated with reduced body weight and calorie intake. Total serum cholesterol concentration was correlated with LXRα transcription in the liver. Folic acid supplementation of the maternal diet may have favorable effects for lipid metabolism in the progeny, but these effects are modified by the postnatal diet and age. Furthermore, the expression of LXRα, PPARα, and PPARγ in the liver and adipose tissue largely depends on the protein and folic acid content in the maternal diet during gestation. However, the altered transcription profile of these key regulators of lipid metabolism does not straightforwardly explain the observed phenotype

    Planning and problem-solving training for patients with schizophrenia: a randomized controlled trial

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    BACKGROUND: The purpose of this study was to assess whether planning and problem-solving training is more effective in improving functional capacity in patients with schizophrenia than a training program addressing basic cognitive functions. METHODS: Eighty-nine patients with schizophrenia were randomly assigned either to a computer assisted training of planning and problem-solving or a training of basic cognition. Outcome variables included planning and problem-solving ability as well as functional capacity, which represents a proxy measure for functional outcome. RESULTS: Planning and problem-solving training improved one measure of planning and problem-solving more strongly than basic cognition training, while two other measures of planning did not show a differential effect. Participants in both groups improved over time in functional capacity. There was no differential effect of the interventions on functional capacity. CONCLUSION: A differential effect of targeting specific cognitive functions on functional capacity could not be established. Small differences on cognitive outcome variables indicate a potential for differential effects. This will have to be addressed in further research including longer treatment programs and other settings

    Extent, intensity and drivers of mammal defaunation:a continental-scale analysis across the Neotropics

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    Neotropical mammal diversity is currently threatened by several chronic human-induced pressures. We compiled 1,029 contemporary mammal assemblages surveyed across the Neotropics to quantify the continental-scale extent and intensity of defaunation and understand their determinants based on environmental covariates. We calculated a local defaunation index for all assemblages—adjusted by a false-absence ratio—which was examined using structural equation models. We propose a hunting index based on socioenvironmental co-variables that either intensify or inhibit hunting, which we used as an additional predictor of defaunation. Mammal defaunation intensity across the Neotropics on average erased 56.5% of the local source fauna, with ungulates comprising the most ubiquitous losses. The extent of defaunation is widespread, but more incipient in hitherto relatively intact major biomes that are rapidly succumbing to encroaching deforestation frontiers. Assemblage-wide mammal body mass distribution was greatly reduced from a historical 95th-percentile of ~ 14 kg to only ~ 4 kg in modern assemblages. Defaunation and depletion of large-bodied species were primarily driven by hunting pressure and remaining habitat area. Our findings can inform guidelines to design transnational conservation policies to safeguard native vertebrates, and ensure that the “empty ecosystem” syndrome will be deterred from reaching much of the New World tropics

    Rates of Influenza and Pneumococcal Vaccination and Correlation With Survival in Multiple Myeloma Patients

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    Background Infections are a common reason for hospitalization and death in multiple myeloma (MM). Although pneumococcal vaccination (PV) and influenza vaccination (FV) are recommended for MM patients, data on vaccination status and outcomes are limited in MM. Materials and Methods We utilized data from the global, prospective, observational INSIGHT MM study to analyze FV and PV rates and associated outcomes of patients with MM enrolled 2016-2019. Results Of the 4307 patients enrolled, 2543 and 2500 had study-entry data on FV and PV status. Overall vaccination rates were low (FV 39.6%, PV 30.2%) and varied by region. On separate multivariable analyses of overall survival (OS) by Cox model, FV in the prior 2 years and PV in the prior 5 years impacted OS (vs. no vaccination; FV: HR, 0.73; 95% CI, 0.60-0.90; P = .003; PV: HR, 0.51; 95% CI, 0.42-0.63; P < .0001) when adjusted for age, region, performance status, disease stage, cytogenetics at diagnosis, MM symptoms, disease status, time since diagnosis, and prior transplant. Proportions of deaths due to infections were lower among vaccinated versus non-vaccinated patients (FV: 9.8% vs. 15.3%, P = .142; PV: 9.9% vs. 18.0%, P = .032). Patients with FV had generally lower health resource utilization (HRU) versus patients without FV; patients with PV had higher or similar HRU versus patients without PV. Conclusion Vaccination is important in MM and should be encouraged. Vaccination status should be recorded in prospective clinical trials as it may affect survival. This trial was registered at www.clinicaltrials.gov as #NCT02761187

    The PLATO 2.0 mission

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    PLATO 2.0 has recently been selected for ESA's M3 launch opportunity (2022/24). Providing accurate key planet parameters (radius, mass, density and age) in statistical numbers, it addresses fundamental questions such as: How do planetary systems form and evolve? Are there other systems with planets like ours, including potentially habitable planets? The PLATO 2.0 instrument consists of 34 small aperture telescopes (32 with 25 s readout cadence and 2 with 2.5 s candence) providing a wide field-of-view (2232 deg 2) and a large photometric magnitude range (4-16 mag). It focusses on bright (4-11 mag) stars in wide fields to detect and characterize planets down to Earth-size by photometric transits, whose masses can then be determined by ground-based radial-velocity follow-up measurements. Asteroseismology will be performed for these bright stars to obtain highly accurate stellar parameters, including masses and ages. The combination of bright targets and asteroseismology results in high accuracy for the bulk planet parameters: 2 %, 4-10 % and 10 % for planet radii, masses and ages, respectively. The planned baseline observing strategy includes two long pointings (2-3 years) to detect and bulk characterize planets reaching into the habitable zone (HZ) of solar-like stars and an additional step-and-stare phase to cover in total about 50 % of the sky. PLATO 2.0 will observe up to 1,000,000 stars and detect and characterize hundreds of small planets, and thousands of planets in the Neptune to gas giant regime out to the HZ. It will therefore provide the first large-scale catalogue of bulk characterized planets with accurate radii, masses, mean densities and ages. This catalogue will include terrestrial planets at intermediate orbital distances, where surface temperatures are moderate. Coverage of this parameter range with statistical numbers of bulk characterized planets is unique to PLATO 2.0. The PLATO 2.0 catalogue allows us to e.g.: - complete our knowledge of planet diversity for low-mass objects, - correlate the planet mean density-orbital distance distribution with predictions from planet formation theories,- constrain the influence of planet migration and scattering on the architecture of multiple systems, and - specify how planet and system parameters change with host star characteristics, such as type, metallicity and age. The catalogue will allow us to study planets and planetary systems at different evolutionary phases. It will further provide a census for small, low-mass planets. This will serve to identify objects which retained their primordial hydrogen atmosphere and in general the typical characteristics of planets in such low-mass, low-density range. Planets detected by PLATO 2.0 will orbit bright stars and many of them will be targets for future atmosphere spectroscopy exploring their atmosphere. Furthermore, the mission has the potential to detect exomoons, planetary rings, binary and Trojan planets. The planetary science possible with PLATO 2.0 is complemented by its impact on stellar and galactic science via asteroseismology as well as light curves of all kinds of variable stars, together with observations of stellar clusters of different ages. This will allow us to improve stellar models and study stellar activity. A large number of well-known ages from red giant stars will probe the structure and evolution of our Galaxy. Asteroseismic ages of bright stars for different phases of stellar evolution allow calibrating stellar age-rotation relationships. Together with the results of ESA's Gaia mission, the results of PLATO 2.0 will provide a huge legacy to planetary, stellar and galactic science

    Laparoscopy in management of appendicitis in high-, middle-, and low-income countries: a multicenter, prospective, cohort study.

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    BACKGROUND: Appendicitis is the most common abdominal surgical emergency worldwide. Differences between high- and low-income settings in the availability of laparoscopic appendectomy, alternative management choices, and outcomes are poorly described. The aim was to identify variation in surgical management and outcomes of appendicitis within low-, middle-, and high-Human Development Index (HDI) countries worldwide. METHODS: This is a multicenter, international prospective cohort study. Consecutive sampling of patients undergoing emergency appendectomy over 6 months was conducted. Follow-up lasted 30 days. RESULTS: 4546 patients from 52 countries underwent appendectomy (2499 high-, 1540 middle-, and 507 low-HDI groups). Surgical site infection (SSI) rates were higher in low-HDI (OR 2.57, 95% CI 1.33-4.99, p = 0.005) but not middle-HDI countries (OR 1.38, 95% CI 0.76-2.52, p = 0.291), compared with high-HDI countries after adjustment. A laparoscopic approach was common in high-HDI countries (1693/2499, 67.7%), but infrequent in low-HDI (41/507, 8.1%) and middle-HDI (132/1540, 8.6%) groups. After accounting for case-mix, laparoscopy was still associated with fewer overall complications (OR 0.55, 95% CI 0.42-0.71, p < 0.001) and SSIs (OR 0.22, 95% CI 0.14-0.33, p < 0.001). In propensity-score matched groups within low-/middle-HDI countries, laparoscopy was still associated with fewer overall complications (OR 0.23 95% CI 0.11-0.44) and SSI (OR 0.21 95% CI 0.09-0.45). CONCLUSION: A laparoscopic approach is associated with better outcomes and availability appears to differ by country HDI. Despite the profound clinical, operational, and financial barriers to its widespread introduction, laparoscopy could significantly improve outcomes for patients in low-resource environments. TRIAL REGISTRATION: NCT02179112
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