52 research outputs found

    Carbon input threshold for soil carbon budget optimization in eroding vineyards

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    Previous studies have documented that, relative to conventional tillage (CT), alternative soil management (reduced tillage, mulching, or cover crops) decreases soil erosion and increases soil organic matter (SOM) in vineyards. These previous studies, however, failed to consider the loss of soil organic carbon (SOC) with erosion that could occur with the adoption of agro-environmental measures (AEM) in a semiarid environment. Accordingly, the aims of this study were to determine whether changes in SOC content under AEM management are always positive and to develop a conceptual model for estimating the "SOC threshold". The SOC threshold was defined as that level of SOC in an AEM-managed vineyard above which erosion will result in greater loss of C than occur in a comparable vineyard with CT management. SOC was analyzed at a 100 paired sites (vineyards with AEM management vs. CT). The results showed that in some cases the loss of C was higher with AEM than with CT. Overall, the results indicate that the SOC threshold may be a key parameter in determining the best AEM measures for vineyards that are on slopes and therefore vulnerable to erosion

    The Next Generation of Axion Helioscopes: The International Axion Observatory (IAXO)

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    The International Axion Observatory (IAXO) is a proposed 4th-generation axion helioscope with the primary physics research goal to search for solar axions via their Primakoff conversion into photons of 1 \u2013 10 keV energies in a strong magnetic field. IAXO will achieve a sensitivity to the axion-photon coupling ga\u3b3 down to a few 710 1212 GeV 121 for a wide range of axion masses up to 3c 0.25 eV. This is an improvement over the currently best (3rd generation) axion helioscope, the CERN Axion Solar Telescope (CAST), of about 5 orders of magnitude in signal strength, corresponding to a factor 3c 20 in the axion photon coupling. IAXO's sensitivity relies on the construction of a large superconducting 8-coil toroidal magnet of 20 m length optimized for axion research. Each of the eight 60 cm diameter magnet bores is equipped with x-ray optics focusing the signal photons into 3c 0.2 cm2 spots that are imaged by very low background x-ray detectors. The magnet will be built into a structure with elevation and azimuth drives that will allow solar tracking for 12 hours each day. This contribution is a summary of our papers [1], [2] and [3] and we refer to these for further details

    Two-pion Bose-Einstein correlations in central Pb-Pb collisions at sNN\sqrt{s_{\rm NN}} = 2.76 TeV

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    The first measurement of two-pion Bose-Einstein correlations in central Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}} = 2.76 TeV at the Large Hadron Collider is presented. We observe a growing trend with energy now not only for the longitudinal and the outward but also for the sideward pion source radius. The pion homogeneity volume and the decoupling time are significantly larger than those measured at RHIC.Comment: 17 pages, 5 captioned figures, 1 table, authors from page 12, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/388

    Suppression of charged particle production at large transverse momentum in central Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}} = 2.76 TeV

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    Inclusive transverse momentum spectra of primary charged particles in Pb-Pb collisions at sNN\sqrt{s_{_{\rm NN}}} = 2.76 TeV have been measured by the ALICE Collaboration at the LHC. The data are presented for central and peripheral collisions, corresponding to 0-5% and 70-80% of the hadronic Pb-Pb cross section. The measured charged particle spectra in η<0.8|\eta|<0.8 and 0.3<pT<200.3 < p_T < 20 GeV/cc are compared to the expectation in pp collisions at the same sNN\sqrt{s_{\rm NN}}, scaled by the number of underlying nucleon-nucleon collisions. The comparison is expressed in terms of the nuclear modification factor RAAR_{\rm AA}. The result indicates only weak medium effects (RAAR_{\rm AA} \approx 0.7) in peripheral collisions. In central collisions, RAAR_{\rm AA} reaches a minimum of about 0.14 at pT=6p_{\rm T}=6-7GeV/cc and increases significantly at larger pTp_{\rm T}. The measured suppression of high-pTp_{\rm T} particles is stronger than that observed at lower collision energies, indicating that a very dense medium is formed in central Pb-Pb collisions at the LHC.Comment: 15 pages, 5 captioned figures, 3 tables, authors from page 10, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/98

    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

    Coulomb dissociation of O-16 into He-4 and C-12

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    We measured the Coulomb dissociation of O-16 into He-4 and C-12 within the FAIR Phase-0 program at GSI Helmholtzzentrum fur Schwerionenforschung Darmstadt, Germany. From this we will extract the photon dissociation cross section O-16(alpha,gamma)C-12, which is the time reversed reaction to C-12(alpha,gamma)O-16. With this indirect method, we aim to improve on the accuracy of the experimental data at lower energies than measured so far. The expected low cross section for the Coulomb dissociation reaction and close magnetic rigidity of beam and fragments demand a high precision measurement. Hence, new detector systems were built and radical changes to the (RB)-B-3 setup were necessary to cope with the high-intensity O-16 beam. All tracking detectors were designed to let the unreacted O-16 ions pass, while detecting the C-12 and He-4

    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

    Ultrahigh energy neutrinos at the Pierre Auger observatory

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    The observation of ultrahigh energy neutrinos (UHEνs) has become a priority in experimental astroparticle physics. UHEνs can be detected with a variety of techniques. In particular, neutrinos can interact in the atmosphere (downward-going ν) or in the Earth crust (Earth-skimming ν), producing air showers that can be observed with arrays of detectors at the ground. With the surface detector array of the Pierre Auger Observatory we can detect these types of cascades. The distinguishing signature for neutrino events is the presence of very inclined showers produced close to the ground (i.e., after having traversed a large amount of atmosphere). In this work we review the procedure and criteria established to search for UHEνs in the data collected with the ground array of the Pierre Auger Observatory. This includes Earth-skimming as well as downward-going neutrinos. No neutrino candidates have been found, which allows us to place competitive limits to the diffuse flux of UHEνs in the EeV range and above.P. Abreu ... K. B. Barber ... J. A. Bellido ... R. W. Clay ... M. J. Cooper ... B. R. Dawson ... T. A. Harrison ... A. E. Herve ... V. C. Holmes ... J. Sorokin ... P. Wahrlich ... B. J. Whelan ... et al

    Dieta de Hemidactylus frenatus (Sauria: Gekkonidae) en un \ue1rea urbana de la regi\uf3n caribe colombiana

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    The aim of this work was to study the diet of Hemidactylus frenatus in an urban area of Colombian Caribbean region. Twenty five specimens were captured on human edifications at the Sincelejo municipality (Sucre). After dissection and analysis of the stomach content, we identify 12 prey groups being Hemiptera the item with the highest importance value index (IVI = 152.7). The data shows a generalist and opportunistic feeding pattern, feeding mainly on arthropods

    Association between source control and mortality in 258 patients with intra-abdominal candidiasis: a retrospective multi-centric analysis comparing intensive care versus surgical wards in Spain

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    Early empiric therapy and adequate resuscitation have been identified as main predictors of outcome in patients with candidemia or bacteremia. Moreover, source control is a major determinant in infectious sites when feasible, as a main technique to reduce microbiological burden. A retrospective, multicenter, cohort study was performed at surgical wards and intensive care units (ICU) of three University Hospitals in Spain between 2010 and 2014, with the aim of improving understanding of the interaction between source control, early antifungal therapy, and use of vasoactives in patients with intra-abdominal candidiasis (IAC). Source control was defined as all physical actions taken to control a focus of infection and reduce the favorable conditions that promote microorganism growth or that maintain the impairment of host defenses. Two hundred and fifty-eight patients with IAC were identified. Sixty-one patients were at ICU for diagnosis. Mortality was higher in the ICU group compared to what was documented for the non-ICU group (35 % vs 19.5 %, p = 0011). Adequate source control within 48 h of diagnosis was achieved in 60 % of the cohort. In multivariate analysis, inadequate source control was identified as the only common risk factor for 30-day mortality in both groups (ICU group OR: 13.78 (95% CI: 2.60\u201372.9, p = 0.002) and non-ICU group OR: 6.53 (95% CI: 2.56\u201316.61, p = <0.001). The population receiving both adequate source control and adequate antifungal treatment was the one associated with a higher survival rate, in both the ICU and surgical groups. Source control remains a key element in IAC, inside and outside the intensive care unit. Early antifungal treatment among ICU patients was associated with lower mortality
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