387 research outputs found

    Comparative analysis of mycorrhizal communities associated with Struthiopteris spicant (L.) Weiss across Europe and North America

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    IntroductionFerns constitute the second largest group of vascular plants. Previous studies have shown that the diversity and composition of fern communities are influenced by resource availability and water stress, among other factors. However, little is known about the influence of these environmental factors on their biotic interactions, especially regarding the relationship between mycorrhizal fungi and ferns. The present study compares the mycorrhizal communities associated with 36 populations of Struthiopteris spicant L. Weiss across Europe and North America. This species exhibits a great tolerance to variations in light, nutrient, and pH conditions, and it can survive with and without mycorrhizae.MethodsWith the aim of determining which environmental factors impact the composition and abundance of the root-associated fungal communities in this species, we used an ITS-focused metabarcoding approach to identify the mycorrhizal fungi present and analyzed the influence of climatic and edaphic variables at global and regional scalesResults and discussionWe encountered striking differences in the relative abundance of arbuscular mycorrhizal fungi (AMF) between S. spicant populations at both spatial levels. We recorded a total of 902 fungal ASVs, but only 2– 4% of the total fungal diversity was observed in each individual, revealing that each fern had a unique fungal community. Light availability and the interactive action of pH and soil nitrogen concentration showed a positive influence on AMF relative abundance, explaining 89% of the variance. However, environmental factors could only explain 4– 8% of the variability in AMF community composition, indicating that it might be determined by stochastic processes. These results support the hypothesis that ferns may be more independent of mycorrhization than other plant groups and interact with fungi in a more opportunistic manner

    Mechanical Ventilation in Patients with End-Stage Idiopathic Pulmonary Fibrosis

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    Background: Acute respiratory failure (ARF) occurring during idiopathic pulmonary fibrosis (IPF) is associated with a poor prognosis. In this subset of individuals, mechanical ventilation (MV) may be required. Objectives: We analysed the characteristics of a group of IPF patients undergoing MV for ARF in order to give some indications on the supposed prognosis. Methods: Hospital records of 34 consecutive patients with IPF, who underwent MV for ARF, were retrospectively examined. Demographic data, time from diagnosis, gas exchange, Acute Physiology and Chronic Health Evaluation (APACHE) II score, ARF causes and MV failure were recorded. Results: Fifteen subjects (group A) underwent invasive MV and 19 patients (group B) non-invasive ventilation (NIV). The 2 groups were different for disease severity (APACHE II score 24.2 ± 6 vs. 19.5 ± 5.9; p = 0.01). Both ventilatory strategies temporarily increased PaO2/FiO2 as compared with spontaneous breathing (group A: 148.5 ± 52 vs. 99 ± 39, p = 0.0004; group B: 134 ± 36 vs. 89 ± 26, p = 0.0004). NIV reduced the respiratory rate (26 ± 7 vs. 36 ± 9 with spontaneous breathing; p = 0.002). Duration of MV correlated with the time of evolution of IPF (r = 0.45; p = 0.018). The in-hospital mortality rate was 85% (100% for invasive MV, 74% for NIV). Four of the 5 survivors died within 6 months from hospital discharge (range 2–6 months). Conclusions: MV does not appear to have a significant impact on the survival of patients with end-stage IPF. NIV may be useful for compassionate use, providing relief from dyspnoea and avoiding aggressive approaches

    Costs and acceptability of simplified monitoring in HIV-suppressed patients switching to dual therapy: the SIMPL’HIV open-label, factorial randomised controlled trial

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    BACKGROUND: Clinical and laboratory monitoring of patients on antiretroviral therapy is an integral part of HIV care and determines whether treatment needs enhanced adherence or modification of the drug regimen. However, different monitoring and treatment strategies carry different costs and health consequences. MATERIALS AND METHODS: The SIMPL’HIV study was a randomised trial that assessed the non-inferiority of dual maintenance therapy. The co-primary outcome was a comparison of costs over 48 weeks of dual therapy with standard antiretroviral therapy and the costs associated with a simplified HIV care approach (patient-centred monitoring [PCM]) versus standard, tri-monthly routine monitoring. Costs included outpatient medical consultations (HIV/non-HIV consultations), non-medical consultations, antiretroviral therapy, laboratory tests and hospitalisation costs. PCM participants had restricted immunological and blood safety monitoring at weeks 0 and 48, and they were offered the choice to complete their remaining study visits via a telephone call, have medications delivered to a specified address, and to have blood tests performed at a location of their choice. We analysed the costs of both strategies using invoices for medical consultations issued by the hospital where the patient was followed, as well as those obtained from health insurance companies. Secondary outcomes included differences between monitoring arms for renal function, lipids and glucose values, and weight over 48 weeks. Patient satisfaction with treatment and monitoring was also assessed using visual analogue scales. RESULTS: Of 93 participants randomised to dolutegravir plus emtricitabine and 94 individuals to combination antiretroviral therapy (median nadir CD4 count, 246 cells/mm3; median age, 48 years; female, 17%),patient-centred monitoring generated no substantial reductions or increases in total costs (US–421peryear[95 –421 per year [95% CI –2292 to 1451]; p = 0.658). However, dual therapy was significantly less expensive (US –2620.4 [95% CI –2864.3 to –2331.4]) compared to standard triple-drug antiretroviral therapy costs. Approximately 50% of participants selected one monitoring option, one-third chose two, and a few opted for three. The preferred option was telephone calls, followed by drug delivery. The number of additional visits outside the study schedule did not differ by type of monitoring. Patient satisfaction related to treatment and monitoring was high at baseline, with no significant increase at week 48. CONCLUSIONS: Patient-centred monitoring did not reduce costs compared to standard monitoring in individuals switching to dual therapy or those continuing combined antiretroviral therapy. In this representative sample of patients with suppressed HIV, antiretroviral therapy was the primary factor driving costs, which may be reduced by using generic drugs to mitigate the high cost of lifelong HIV treatment. Trial registration: ClinicalTrials.gov NCT03160105

    Role of the HIV-1 Reservoir to Maintain Viral Suppression in a Simplified Strategy for the Long-Term Management of HIV-1 Infection (The SIMPL’HIV Trial).

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    HIV-1 reservoir size and dynamics are promising parameters to ensure the safe prescription of simplified maintenance antiretroviral therapy in chronically HIV-1 infected patients. In the SIMPL’HIV trial, HIV-1 DNA was quantified in peripheral blood mononuclear cells obtained at baseline and week 48 to investigate changes over time and evidence of a predictive relationship to maintain HIV-1 RNA <20 copies/ml. Measurements were available for 175 patients, with no differences observed between treatment strategies. Findings showed that baseline HIV-1 DNA was lower in those with durable HIV-1 RNA <20 copies/ml compared with patients with incomplete viral suppression over 48 weeks

    Hunt for new phenomena using large jet multiplicities and missing transverse momentum with ATLAS in 4.7 fb−1 of s√=7TeV proton-proton collisions

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    Results are presented of a search for new particles decaying to large numbers of jets in association with missing transverse momentum, using 4.7 fb−1 of pp collision data at s√=7TeV collected by the ATLAS experiment at the Large Hadron Collider in 2011. The event selection requires missing transverse momentum, no isolated electrons or muons, and from ≄6 to ≄9 jets. No evidence is found for physics beyond the Standard Model. The results are interpreted in the context of a MSUGRA/CMSSM supersymmetric model, where, for large universal scalar mass m 0, gluino masses smaller than 840 GeV are excluded at the 95% confidence level, extending previously published limits. Within a simplified model containing only a gluino octet and a neutralino, gluino masses smaller than 870 GeV are similarly excluded for neutralino masses below 100 GeV

    Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS

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    The chi_b(nP) quarkonium states are produced in proton-proton collisions at the Large Hadron Collider (LHC) at sqrt(s) = 7 TeV and recorded by the ATLAS detector. Using a data sample corresponding to an integrated luminosity of 4.4 fb^-1, these states are reconstructed through their radiative decays to Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new structure centered at a mass of 10.530+/-0.005 (stat.)+/-0.009 (syst.) GeV is also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes. This is interpreted as the chi_b(3P) system.Comment: 5 pages plus author list (18 pages total), 2 figures, 1 table, corrected author list, matches final version in Physical Review Letter

    Search for displaced vertices arising from decays of new heavy particles in 7 TeV pp collisions at ATLAS

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    We present the results of a search for new, heavy particles that decay at a significant distance from their production point into a final state containing charged hadrons in association with a high-momentum muon. The search is conducted in a pp-collision data sample with a center-of-mass energy of 7 TeV and an integrated luminosity of 33 pb^-1 collected in 2010 by the ATLAS detector operating at the Large Hadron Collider. Production of such particles is expected in various scenarios of physics beyond the standard model. We observe no signal and place limits on the production cross-section of supersymmetric particles in an R-parity-violating scenario as a function of the neutralino lifetime. Limits are presented for different squark and neutralino masses, enabling extension of the limits to a variety of other models.Comment: 8 pages plus author list (20 pages total), 8 figures, 1 table, final version to appear in Physics Letters

    Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC

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    Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H →γ Îł, H → Z Z∗ →4l and H →W W∗ →lÎœlÎœ. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV, corresponding to an integrated luminosity of about 25 fb−1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined ïŹts probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson

    Standalone vertex ïŹnding in the ATLAS muon spectrometer

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    A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at √s = 7 TeV collected with the ATLAS detector at the LHC during 2011

    Measurement of the top quark-pair production cross section with ATLAS in pp collisions at \sqrt{s}=7\TeV

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    A measurement of the production cross-section for top quark pairs(\ttbar) in pppp collisions at \sqrt{s}=7 \TeV is presented using data recorded with the ATLAS detector at the Large Hadron Collider. Events are selected in two different topologies: single lepton (electron ee or muon Ό\mu) with large missing transverse energy and at least four jets, and dilepton (eeee, ΌΌ\mu\mu or eΌe\mu) with large missing transverse energy and at least two jets. In a data sample of 2.9 pb-1, 37 candidate events are observed in the single-lepton topology and 9 events in the dilepton topology. The corresponding expected backgrounds from non-\ttbar Standard Model processes are estimated using data-driven methods and determined to be 12.2±3.912.2 \pm 3.9 events and 2.5±0.62.5 \pm 0.6 events, respectively. The kinematic properties of the selected events are consistent with SM \ttbar production. The inclusive top quark pair production cross-section is measured to be \sigmattbar=145 \pm 31 ^{+42}_{-27} pb where the first uncertainty is statistical and the second systematic. The measurement agrees with perturbative QCD calculations.Comment: 30 pages plus author list (50 pages total), 9 figures, 11 tables, CERN-PH number and final journal adde
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