19 research outputs found

    Update on the correlation of the highest energy cosmic rays with nearby extragalactic matter

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    Data collected by the Pierre Auger Observatory through 31 August 2007 showed evidence for anisotropy in the arrival directions of cosmic rays above the Greisen-Zatsepin-Kuz'min energy threshold, \nobreak{6×10196\times 10^{19}eV}. The anisotropy was measured by the fraction of arrival directions that are less than 3.1∘3.1^\circ from the position of an active galactic nucleus within 75 Mpc (using the V\'eron-Cetty and V\'eron 12th12^{\rm th} catalog). An updated measurement of this fraction is reported here using the arrival directions of cosmic rays recorded above the same energy threshold through 31 December 2009. The number of arrival directions has increased from 27 to 69, allowing a more precise measurement. The correlating fraction is (38−6+7)(38^{+7}_{-6})%, compared with 2121% expected for isotropic cosmic rays. This is down from the early estimate of (69−13+11)(69^{+11}_{-13})%. The enlarged set of arrival directions is examined also in relation to other populations of nearby extragalactic objects: galaxies in the 2 Microns All Sky Survey and active galactic nuclei detected in hard X-rays by the Swift Burst Alert Telescope. A celestial region around the position of the radiogalaxy Cen A has the largest excess of arrival directions relative to isotropic expectations. The 2-point autocorrelation function is shown for the enlarged set of arrival directions and compared to the isotropic expectation.Comment: Accepted for publication in Astroparticle Physics on 31 August 201

    Trigger and Aperture of the Surface Detector Array of the Pierre Auger Observatory

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    The surface detector array of the Pierre Auger Observatory consists of 1600 water-Cherenkov detectors, for the study of extensive air showers (EAS) generated by ultra-high-energy cosmic rays. We describe the trigger hierarchy, from the identification of candidate showers at the level of a single detector, amongst a large background (mainly random single cosmic ray muons), up to the selection of real events and the rejection of random coincidences. Such trigger makes the surface detector array fully efficient for the detection of EAS with energy above 3×10183\times 10^{18} eV, for all zenith angles between 0∘^\circ and 60∘^\circ, independently of the position of the impact point and of the mass of the primary particle. In these range of energies and angles, the exposure of the surface array can be determined purely on the basis of the geometrical acceptance.Comment: 29 pages, 12 figure

    Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study

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    Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28–2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65–3·22], p\textless0·0001), American Society of Anesthesiologists grades 3–5 versus grades 1–2 (2·35 [1·57–3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01–2·39], p=0·046), emergency versus elective surgery (1·67 [1·06–2·63], p=0·026), and major versus minor surgery (1·52 [1·01–2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research

    An?lisis de la demanda de productos l?cteos y la aplicaci?n de un modelo de equilibrio espacial para el mercado de leche pasteurizada en Honduras: algunas estimaciones del impacto del DR-CAFTA

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    Tesis (M. Sc) -- CATIE, Turrialba (Costa Rica), 2008El Tratado de Libre Comercio entre Centroam?rica, Estados Unidos de Am?rica y la Rep?blica Dominicana (DR-CAFTA), modificar? los flujos comerciales entre estos pa?ses, afectando la demanda y oferta de productos agr?colas, incluidos los derivados l?cteos. Sin embargo, los productos l?cteos m?s substituibles (leches fluida pasteurizada) podr?an ser afectados. La mejora en productividad y la reducci?n de costos de transporte aumentan el bienestar tanto de productores y consumidores. Por otro lado, la importaci?n de leche a precios menores aumenta el bienestar del consumidor, pero no del productor. The United States of America, Dominican Republic and Central America Free Trade Agreement (DR-CAFTA), will amend trade flows between these countries, affecting demand and supply of agricultural products, including dairy products. However, dairy products more substitutable (pasteurized milk fluid) could be affected. The improvement in productivity and reducing transportation costs increase the welfare of both producers and consumers. On the other hand, imports of milk at lower prices increases consumer welfare, but not the producer???s

    Carbon storage in a Ferrosol under subtropical rainforest, tree plantations, and pasture is linked to soil aggregation

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    Soil is a large sink for carbon (C), with the potential to significantly reduce the net increase in atmospheric CO concentration. However, we previously showed that subtropical tree plantations store less C into long-term soil pools than rainforest or pasture. To explore reasons for differences in C storage between different land-use systems, we examined the relationships between soil aggregation, iron and aluminium oxide and hydroxide content, and soil organic C (SOC) under exotic C pasture (Pennisetum clandestinum), native hoop pine (Araucaria cunninghamii) plantations, and rainforest. We measured SOC concentrations of water-stable and fully dispersed aggregates to assess the location of soil C. Concentrations of dithionite- and oxalate-extractable iron and aluminium were also determined to assess their role in SOC sequestration. Soil under rainforest and pasture contained more C in intra-aggregate particulate organic matter (iPOM, >53m) than hoop pine plantations, indicating that in rainforest and pasture, greater tabilisation of SOC occurred via soil aggregation. SOC was not significantly correlated with dithionite- and oxalate-extractable Fe and Al in these systems, ndicating that sorption sites of Fe and Al oxides and hydroxides were saturated. We concluded that soil C under rainforest and pasture is stabilised by incorporation within soil aggregates, which results in greater storage of C in soil under pasture than plantations following land-use change. The reduced storage of C as iPOM in plantation soil contributes to the negative soil C budget of plantations compared with rainforest and pasture, even 63 years after establishment. The results have relevance for CO mitigation schemes based on tree plantations

    Genetics of arrhythmogenic right ventricular cardiomyopathy

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    Arrhythmogenic right ventricular cardiomyopathy is a rare clinical entity characterised by fibro-fatty replacement of myocardium, mainly involving right ventricular free wall, leading to malignant electrical instability and sudden cardiac death. The disease is inherited in up to 50% of cases, with incomplete penetrance and variable phenotypic expression. To date, more than 300 pathogenic mutations have been identified in 12 genes, mainly with autosomal dominant inheritance. Here, we focus on recent advances in the genetics of arrhythmogenic right ventricular cardiomyopathy. Despite continuous improvements, current genotype-phenotype studies have not contributed yet to establish a genetic risk stratification of the disease
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