174 research outputs found

    Competing effects of mass anisotropy and spin Zeeman coupling on the upper critical field of a mixed dd- and s-wave superconductor

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    Based on the linearized Eilenberger equations, the upper critical field (Hc2)(H_{c2}) of mixed d- and s-wave superconductors has been microscopically studied with an emphasis on the competing effects of mass anisotropy and spin Zeeman coupling. We find the mass anisotropy always enhance Hc2H_{c2} while the Zeeman interaction suppresses Hc2H_{c2}. As required by the thermodynamics, we find Hc2H_{c2} is saturated at zero temperature. We compare the theoretical calculations with recent experimental data of YBa2_{2}Cu3_{3}O7+AFwdelta_{7-+AFw-delta}.Comment: To appear in PRB in Feb. 200

    Dynamical chiral symmetry breaking in gauge theories with extra dimensions

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    We investigate dynamical chiral symmetry breaking in vector-like gauge theories in DD dimensions with (D4D-4) compactified extra dimensions, based on the gap equation (Schwinger-Dyson equation) and the effective potential for the bulk gauge theories within the improved ladder approximation. The non-local gauge fixing method is adopted so as to keep the ladder approximation consistent with the Ward-Takahashi identities. Using the one-loop MSˉ\bar{\rm MS} gauge coupling of the truncated KK effective theory which has a nontrivial ultraviolet fixed point (UV-FP) gg_* for the (dimensionless) bulk gauge coupling g^{\hat g}, we find that there exists a critical number of flavors, NfcritN_f^{\rm crit} (4.2,1.8\simeq 4.2, 1.8 for D=6,8D=6, 8 for SU(3) gauge theory): For Nf>NfcritN_f > N_f^{\rm crit}, the dynamical chiral symmetry breaking takes place not only in the ``strong-coupling phase'' (g^>g{\hat g} >g_*) but also in the ``weak-coupling phase'' (g^<g{\hat g} <g_*) when the cutoff is large enough. For Nf<NfcritN_f < N_f^{\rm crit}, on the other hand, only the strong-coupling phase is a broken phase and we can formally define a continuum (infinite cutoff) limit, so that the physics is insensitive to the cutoff in this case. We also perform a similar analysis using the one-loop ``effective gauge coupling''. We find the NfcritN_f^{\rm crit} turns out to be a value similar to that of the MSˉ\bar{\rm MS} case, notwithstanding the enhancement of the coupling compared with that of the MSˉ\bar{\rm MS}.Comment: REVTEX4, 38 pages, 18 figures. The abstract is shortened; version to be published in Phys. Rev.

    Stakeholder perceptions of key aspects of high-quality cancer care to assess with patient reported outcome measures: A systematic review

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    Performance measurement is the process of collecting, analyzing, and reporting standard-ized measures of clinical performance that can be compared across practices to evaluate how well care was provided. We conducted a systematic review to identify stakeholder perceptions of key symptoms and health domains to test as patient-reported performance measures in oncology. Stakeholders included cancer patients, caregivers, clinicians, and healthcare administrators. Standard review methodology was used, consistent with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses). MEDLINE/PubMed, EMBASE, and the Cochrane Library were searched to identify relevant studies through August 2020. Four coders independently reviewed entries and con-flicts were resolved by a fifth coder. Efficacy and effectiveness studies, and studies focused exclusively on patient experiences of care (e.g., communication skills of providers) were excluded. Searches generated 1813 articles and 1779 were coded as not relevant, leaving 34 international articles for extraction. Patients, caregivers, clinicians, and healthcare administrators prioritize psychosocial care (e.g., distress) and symptom management for patient-reported performance measures. Patients and caregivers also perceive that maintaining physical function and daily activities are critical. Clinicians and administrators perceive control of specific symptoms to be critical (gastrointestinal symptoms, pain, poor sleep). Results were used to inform testing at six US cancer centers

    Gravitational Lensing by Black Holes

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    We review the theoretical aspects of gravitational lensing by black holes, and discuss the perspectives for realistic observations. We will first treat lensing by spherically symmetric black holes, in which the formation of infinite sequences of higher order images emerges in the clearest way. We will then consider the effects of the spin of the black hole, with the formation of giant higher order caustics and multiple images. Finally, we will consider the perspectives for observations of black hole lensing, from the detection of secondary images of stellar sources and spots on the accretion disk to the interpretation of iron K-lines and direct imaging of the shadow of the black hole.Comment: Invited article for the GRG special issue on lensing (P. Jetzer, Y. Mellier and V. Perlick Eds.). 31 pages, 12 figure

    Hydrodynamic Limit of the Boltzmann Equation with Contact Discontinuities

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    The hydrodynamic limit for the Boltzmann equation is studied in the case when the limit system, that is, the system of Euler equations contains contact discontinuities. When suitable initial data is chosen to avoid the initial layer, we prove that there exists a unique solution to the Boltzmann equation globally in time for any given Knudsen number. And this family of solutions converge to the local Maxwellian defined by the contact discontinuity of the Euler equations uniformly away from the discontinuity as the Knudsen number ε\varepsilon tends to zero. The proof is obtained by an appropriately chosen scaling and the energy method through the micro-macro decomposition.Comment: 34 pages. submitte

    Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

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    A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

    Budgeting in an open system

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    Budgeting is broadly used as a tool for organizational management. And this is a reason for continuous looking for budgeting essence. In the paper the systems approach is applied to investigating the nature of budgeting. The systemic aspect of an organization and the systems approach to management were taken into account. Budgeting is seen as the process of prediction and communication of systemic attributes of an organization. It seems that the results reached point to the systems approach as a basis for general theory of both budgeting and accounting.O orçamento é amplamente utilizado como uma ferramenta de gestão organizacional. Este é um dos motivos pela busca permanente da essência do orçamento. Neste estudo, a abordagem sistêmica é aplicada à análise da natureza do orçamento. Foram considerados o aspecto sistêmico de uma organização e a abordagem sistêmica à gestão. O orçamento é entendido como o processo de previsão e comunicação de atributos sistêmico de uma organização. Parece que os resultados alcançados indicam a abordagem sistêmica como base de uma teoria geral de orçamento e contabilidade

    Measurement of the View the tt production cross-section using eμ events with b-tagged jets in pp collisions at √s = 13 TeV with the ATLAS detector

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    This paper describes a measurement of the inclusive top quark pair production cross-section (σtt¯) with a data sample of 3.2 fb−1 of proton–proton collisions at a centre-of-mass energy of √s = 13 TeV, collected in 2015 by the ATLAS detector at the LHC. This measurement uses events with an opposite-charge electron–muon pair in the final state. Jets containing b-quarks are tagged using an algorithm based on track impact parameters and reconstructed secondary vertices. The numbers of events with exactly one and exactly two b-tagged jets are counted and used to determine simultaneously σtt¯ and the efficiency to reconstruct and b-tag a jet from a top quark decay, thereby minimising the associated systematic uncertainties. The cross-section is measured to be: σtt¯ = 818 ± 8 (stat) ± 27 (syst) ± 19 (lumi) ± 12 (beam) pb, where the four uncertainties arise from data statistics, experimental and theoretical systematic effects, the integrated luminosity and the LHC beam energy, giving a total relative uncertainty of 4.4%. The result is consistent with theoretical QCD calculations at next-to-next-to-leading order. A fiducial measurement corresponding to the experimental acceptance of the leptons is also presented

    Search for TeV-scale gravity signatures in high-mass final states with leptons and jets with the ATLAS detector at sqrt [ s ] = 13TeV

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    A search for physics beyond the Standard Model, in final states with at least one high transverse momentum charged lepton (electron or muon) and two additional high transverse momentum leptons or jets, is performed using 3.2 fb−1 of proton–proton collision data recorded by the ATLAS detector at the Large Hadron Collider in 2015 at √s = 13 TeV. The upper end of the distribution of the scalar sum of the transverse momenta of leptons and jets is sensitive to the production of high-mass objects. No excess of events beyond Standard Model predictions is observed. Exclusion limits are set for models of microscopic black holes with two to six extra dimensions
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