3,426 research outputs found

    Dirac Quantization Condition for Monopole in Noncommutative Space-Time

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    Since the structure of space-time at very short distances is believed to get modified possibly due to noncommutativity effects and as the Dirac Quantization Condition (DQC), ÎŒe=N2ℏc\mu e = \frac{N}{2}\hbar c, probes the magnetic field point singularity, a natural question arises whether the same condition will still survive. We show that the DQC on a noncommutative space in a model of dynamical noncommutative quantum mechanics remains the same as in the commutative case to first order in the noncommutativity parameter Ξ\theta, leading to the conjecture that the condition will not alter in higher orders.Comment: 11 page

    Quality of Life in Patients with Small Abdominal Aortic Aneurysm: The Effect of Early Endovascular Repair Versus Surveillance in the CAESAR Trial

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    AbstractObjectiveTo evaluate and compare changes over time in health-related quality of life reported by patients with small (4.1–5.4 cm) abdominal aortic aneurysms (AAAs) undergoing endovascular aortic aneurysm repair (EVAR) or surveillance.MethodsParticipants were randomly assigned to receive either early EVAR or surveillance within a multicentre, randomised clinical trial on small AAA (Comparison of surveillance vs. Aortic Endografting for Small Aneurysm Repair, CAESAR). Patient-reported health-related quality of life was assessed before randomisation, at 6 months and yearly thereafter using the Short Form 36 (SF-36) Health Survey.ResultsBetween 2004 and 2008, 360 patients (345 males, mean age 68.9 years) were randomised, 182 to early EVAR and 178 to surveillance. There was one perioperative death. Mean follow-up was 31.8 months. No significant difference in survival was found. At baseline, comparable quality of life scores were recorded in both treatment groups: Total SF-36: 73.0 versus 75.5 (p = 0.18), Physical domain: 71.4 versus 73.3 (p = 0.33); Mental health domain: 70.9 versus 72.7 (p = 0.33), in the EVAR arm versus the surveillance arm, respectively. Six months after randomisation, Total SF-36 and Physical and Mental domain scores were all significantly higher with respect to baseline in the EVAR group, while patients of the surveillance group scored lower. The differences between EVAR and surveillance arms in score changes at 6 months were significant and in favour of EVAR: Total score: difference 5.4; p = 0.0017; Physical: difference 3.8; p = 0.02; and Mental: difference 6.0; p = 0.0005. Differences between EVAR and surveillance diminished over time. At the last assessment, patients in both groups had decreased scores with a significant drop with respect to the baseline (−3.9 in EVAR, −6.3 in surveillance). There were no significant differences between the EVAR and surveillance arms: Total score: p = 0.25; Physical: p = 0.47; and Mental: p = 0.38.ConclusionsPatients with small AAA under surveillance compared with early EVAR had significant impaired functional health at 6 months after assignment. After a mean of 31.8 months, SF-36 health-related quality of life in patients allocated to early EVAR and surveillance was similar

    Second-generation Thienopyridine use is not Associated with Better Early Perioperative Outcome During Carotid Stenting

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    AbstractObjectiveManagement of anti-platelet therapy during carotid artery stenting (CAS) is mainly based on indirect evidence from coronary stenting experience. There is common agreement on the use of thienopyridine (mainly second-generation) during CAS, but some patients are unsuitable for clopidogrel treatment and data on the benefit of its use in large CAS populations are lacking. The aim of this study was to investigate whether clopidogrel was associated with reduced perioperative morbidity in patients undergoing CAS.MethodsConsecutive patients undergoing CAS for primary carotid stenosis from 2004 to 2009 were reviewed. The independent association of clopidogrel and perioperative morbidity was assessed using multivariable analysis.ResultsA total of 1083 patients were treated (29% females, mean age 71.6 years); 825 (76%) patients were given clopidogrel starting before treatment. Clopidogrel use was associated with a non-significant reduction of perioperative stroke/death (4.3% vs. 2.4%; p = 0.13) and disabling stroke (1.2% vs. 1.0%; p = 1) rates. The non-significant stroke/death difference was similar in symptomatic (5.8% vs. 4.0%, p = 0.37) and asymptomatic (3.7% vs. 1.9%; p = 0.17) patients. After adjusting for demographics, co-morbidities and other therapies with multivariable analysis, clopidogrel use failed to show any significant independent association in decreasing operative risks. The only independent protective factor was use of statins (p = 0.010). The additional use of dual anti-platelet therapy did not add any advantage to the use of clopidogrel alone.ConclusionsThe suggested benefit of clopidogrel in decreasing the incidence of complications in patients undergoing CAS may be overestimated due to the overlapping effect of other more relevant factors (e.g., pleiotropy and plaque stabilisation from statins). More data and level I evidence are needed to understand which is the best medical management of CAS that will help improve outcomes of the procedure

    Higgs boson production at the LHC using the qTq_T subtraction formalism at N3LON^3LO QCDQCD

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    We consider higher-order QCD corrections to Higgs boson production through gluon-gluon fusion in the large top quark mass limit in hadron collisions. We extend the transverse-momentum (qT ) subtraction method to next-to-next-to-next-to-leading order (N3LO) and combine it with the NNLO Higgs-plus-jet calculation to numerically compute differential infrared-safe observables at N3LO for Higgs boson production in gluon fusion. To cancel the infrared divergences, we exploit the universal behaviour of the associated qT distributions in the small-qT region. We document all the necessary ingredients of the transverse-momentum subtraction method up to N3LO. The missing third-order collinear functions, which contribute only at qT = 0, are approximated using a prescription which uses the known result for the total Higgs boson cross section at this order. As a first application of the third-order qT subtraction method, we present the N3LO rapidity distribution of the Higgs boson at the LHC

    Les Houches 2013: Physics at TeV Colliders: Standard Model Working Group Report

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    This Report summarizes the proceedings of the 2013 Les Houches workshop on Physics at TeV Colliders. Session 1 dealt primarily with (1) the techniques for calculating standard model multi-leg NLO and NNLO QCD and NLO EW cross sections and (2) the comparison of those cross sections with LHC data from Run 1, and projections for future measurements in Run 2.Comment: Proceedings of the Standard Model Working Group of the 2013 Les Houches Workshop, Physics at TeV Colliders, Les houches 3-21 June 2013. 200 page

    Short-term economic impact of the Zika virus outbreak

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    Summary Zika virus (ZIKV) is mainly transmitted by mosquitoes bites. However, transmission by sexual contacts has been reported in 11 non endemic countries. The rapid spread of ZIKV in Latin American and Caribbean Countries (LCR), person-to-person transmission and perceived risk on people’s well being can affect the emerging economies of LCR which historically dependent on truism. Here we present an analysis on economic outputs for assessing the current impact of ZIKV on markets. Our analysis show an unexpected resilience of LCR markets to international alerts. This positive response represents an opportunity to scale-up interventions for preventing the further spreading of the ZIKV epidemic

    Les Houches 2015: Physics at TeV Colliders Standard Model Working Group Report

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    This Report summarizes the proceedings of the 2015 Les Houches workshop on Physics at TeV Colliders. Session 1 dealt with (I) new developments relevant for high precision Standard Model calculations, (II) the new PDF4LHC parton distributions, (III) issues in the theoretical description of the production of Standard Model Higgs bosons and how to relate experimental measurements, (IV) a host of phenomenological studies essential for comparing LHC data from Run I with theoretical predictions and projections for future measurements in Run II, and (V) new developments in Monte Carlo event generators.Comment: Proceedings of the Standard Model Working Group of the 2015 Les Houches Workshop, Physics at TeV Colliders, Les Houches 1-19 June 2015. 227 page

    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

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    A search for supersymmetry through the pair production of electroweakinos with mass splittings near the electroweak scale and decaying via on-shell W and Z bosons is presented for a three-lepton final state. The analyzed proton-proton collision data taken at a center-of-mass energy of √s=13  TeV were collected between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 139  fb−1. A search, emulating the recursive jigsaw reconstruction technique with easily reproducible laboratory-frame variables, is performed. The two excesses observed in the 2015–2016 data recursive jigsaw analysis in the low-mass three-lepton phase space are reproduced. Results with the full data set are in agreement with the Standard Model expectations. They are interpreted to set exclusion limits at the 95% confidence level on simplified models of chargino-neutralino pair production for masses up to 345 GeV

    Search for direct stau production in events with two hadronic tau-leptons in root s=13 TeV pp collisions with the ATLAS detector

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    A search for the direct production of the supersymmetric partners ofτ-leptons (staus) in final stateswith two hadronically decayingτ-leptons is presented. The analysis uses a dataset of pp collisions corresponding to an integrated luminosity of139fb−1, recorded with the ATLAS detector at the LargeHadron Collider at a center-of-mass energy of 13 TeV. No significant deviation from the expected StandardModel background is observed. Limits are derived in scenarios of direct production of stau pairs with eachstau decaying into the stable lightest neutralino and oneτ-lepton in simplified models where the two staumass eigenstates are degenerate. Stau masses from 120 GeV to 390 GeV are excluded at 95% confidencelevel for a massless lightest neutralino
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