1,550 research outputs found

    Measurements of Higgs boson production cross section and CP violation in the H → τ τ decay channel with the ATLAS detector

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    The H → τ τ decay is an important decay mode of the Higgs as it allows to measure directly the Higgs coupling to fermions. This paper presents the measurement of the H → τ τ cross section performed with the Run 1 dataset (2011–2012) collected by the ATLAS experiment and describes future perspectives for the Run 2 of the LHC, with particular emphasis on the importance of theory uncertainties for this channel. In addition a CP violation measurement in the Vector Boson Fusion production of the Higgs will be shown, that demonstrates how the H → τ τ channel allows to measure the Higgs CP properties as well

    Cervical Laminoplasty with Polypropylene Mesh: Our Experience

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    Cervical laminoplasty was made to reduce the complications of the simple laminectomy. The main indication is degenerative cervical myelopathy with posterior compression to two or more levels. To simplify this procedure with more effectiveness, we conceived a cervical laminoplastica with polypropylene mesh, generally used in abdominoplasty, to provide more resistance during mechanisms of flexion-extension. MATERIALS AND METHODS: We analyzed 35 patients (27 males, 8 females) with degenerative cervical myelopathy who underwent surgical tretament at our institution between 2010 and 2015. RESULTS AND DISCUSSION: The main duration of surgery was about 90 minutes without intra or post-operative complications. Clinical and radiological follow-up was done at 1, 3 and 6 months, with cervical dynamic Rx and cervical RM at 1one year. There were no complications and 70% of the patients experienced a stable clinical improvement, while in 30% of patients stabilization of clinical deficits. The duration of the superior clinical to one year and the age gt of 70 years the more meaningful negative prognostic indicators have appeared. CONCLUSIONS: A clinical history more than one year and the age elder than 70 years appear the main negative prognostic factors. The advantage of the laminoplasty is a smaller anatomical damage of the posterior elements without cervical instability, and use of polypropylene mesh provides more resistance during flexion-extension

    Two-fluid barotropic models for powder-snow avalanche flows

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    14 pages, 1 figure. Accepted to Springer series "Notes on Numerical Fluid Mechanics and Multidisciplinary Design". Other authors papers can be downloaded at http://www.lama.univ-savoie.fr/~dutykh/International audienceIn the present study we discuss several modeling issues of powder-snow avalanche flows. We take a two-fluid modeling paradigm. For the sake of simplicity, we will restrict our attention to barotropic equations. We begin the exposition by a compressible model with two velocities for each fluid. However, this model may become non-hyperbolic and thus, represents serious challenges for numerical methods. To overcome these issues, we derive a single velocity model as a result of a relaxation process. This model can be easily shown to be hyperbolic for any reasonable equation of state. Finally, an incompressible limit of this model is derived

    ANMCO/SIC/SICI-GISE/SICCH Executive Summary of Consensus Document on Risk Stratification in elderly patients with aortic stenosis before surgery or transcatheter aortic valve replacement

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    Aortic stenosis is one of the most frequent valvular diseases in developed countries, and its impact on public health resources and assistance is increasing. A substantial proportion of elderly people with severe aortic stenosis is not eligible to surgery because of the advanced age, frailty, and multiple co-morbidities. Transcatheter aortic valve implantation (TAVI) enables the treatment of very elderly patients at high or prohibitive surgical risk considered ineligible for surgery and with an acceptable life expectancy. However, a significant percentage of patients die or show no improvement in quality of life (QOL) in the follow-up. In the decision-making process, it is important to determine: (i) whether and how much frailty of the patient influences the risk of procedures; (ii) how the QOL and the individual patient's survival are influenced by aortic valve disease or from other associated conditions; and (iii) whether a geriatric specialist intervention to evaluate and correct frailty or other diseases with their potential or already manifest disabilities can improve the outcome of surgery or TAVI. Consequently, in addition to risk stratification with conventional tools, a number of factors including multi-morbidity, disability, frailty, and cognitive function should be considered, in order to assess the expected benefit of both surgery and TAVI. The pre-operative optimization through a multidisciplinary approach with a Heart Team can counteract the multiple damage (cardiac, neurological, muscular, respiratory, and kidney) that can potentially aggravate the reduced physiological reserves characteristic of frailty. The systematic application in clinical practice of multidimensional assessment instruments of frailty and cognitive function in the screening and the adoption of specific care pathways should facilitate this task

    Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

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    This paper presents measurements of the W+μ+νW^+ \rightarrow \mu^+\nu and WμνW^- \rightarrow \mu^-\nu cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13

    Search for chargino-neutralino production with mass splittings near the electroweak scale in three-lepton final states in √s=13 TeV pp collisions with the ATLAS detector