792 research outputs found

    Symmetry aspects of fermions coupled to torsion and electromagnetic fields

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    We study and explore the symmetry properties of fermions coupled to dynamical torsion and electromagnetic fields. The stability of the theory upon radiative corrections as well as the presence of anomalies are investigated.Comment: 9 pages, LaTe

    Long-term effectiveness of a multifaceted intervention on pain management in a walk-in clinic

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    Background: Pain is a common complaint of patients attending walk-in clinics, but timely and appropriate pain management is often lacking. Aim: To evaluate the impact of a multifaceted intervention on pain management. Design: Prospective interventional study. Methods: Three cross-sectional surveys were conducted: before, 4 months after and 14 months after a multifaceted intervention at the medical walk-in clinic of a university hospital. The intervention included both educational activities and structural changes. Use of recommended pain management procedures, pain relief and overall assessments of pain treatment and health professionals' attitudes were assessed using patient questionnaires, collected by mail. History of pain, records of pain intensity and use of pain medication were extracted from medical files. Results: We analysed 1409 medical files and 695 questionnaires of patients presenting with pain. Documentation of pain intensity and administration of pain medication at the walk-in clinic improved significantly 14 months after the intervention (7% vs. 53% and 17% vs. 27%, respectively, p < 0.001) and pain medication was more often administered by the oral route (14% vs. 23%, p < 0.001). However, no change was observed for complete pain relief (40% vs. 39%, p = 0.92) or patients' overall assessments of pain management. Discussion: The intervention improved adherence to recommended procedures, even in the longer term, but did not result in better patient outcomes. Continuing efforts are needed to help health professionals improve pain management in out-patient car

    Study of the Gribov region in Euclidean Yang-Mills theories in the maximal Abelian gauge

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    The properties of the Gribov region in SU(2) Euclidean Yang-Mills theories in the maximal Abelian gauge are investigated. This region turns out to be bounded in all off-diagonal directions, while it is unbounded along the diagonal one. The soft breaking of the BRST invariance due to the restriction of the domain of integration in the path integral to the Gribov region is scrutinized. Owing to the unboundedness in the diagonal direction, the invariance with respect to Abelian transformations is preserved, a property which is at the origin of the local U(1) Ward identity of the maximal Abelian gauge.Comment: 15 pages, one reference added, version accepted for publication in Phys. Rev.

    A Completely Invariant SUSY Transform of Supersymmetric QED

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    We study the SUSY breaking of the covariant gauge-fixing term in SUSY QED and observe that this corresponds to a breaking of the Lorentz gauge condition by SUSY. Reasoning by analogy with SUSY's violation of the Wess-Zumino gauge, we argue that the SUSY transformation, already modified to preserve Wess-Zumino gauge, should be further modified by another gauge transformation which restores the Lorentz gauge condition. We derive this modification and use the resulting transformation to derive a Ward identitiy relating the photon and photino propagators without using ghost fields. Our transformation also fulfills the SUSY algebra, modulo terms that vanish in Lorentz gauge

    A nilpotent symmetry of quantum gauge theories

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    For the Becchi-Rouet-Stora-Tyutin (BRST) invariant extended action for any gauge theory, there exists another off-shell nilpotent symmetry. For linear gauges, it can be elevated to a symmetry of the quantum theory and used in the construction of the quantum effective action. Generalizations for nonlinear gauges and actions with higher order ghost terms are also possible.Comment: RevTeX, 9 pages, several changes to include generalizations to quartic and higher ghost terms and non-linear gauges. Abstract changed. Final version to be publishe

    Superconformal Symmetry, The Supercurrent And Non-BPS Brane Dynamics

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    The Noether currents associated with the non-linearly realized super-Poincare' symmetries of the Green-Schwarz (Nambu-Goto-Akulov-Volkov) action for a non-BPS p=2 brane embedded in a N=1, D=4 target superspace are constructed. The R symmetry current, the supersymmetry currents, the energy-momentum tensor and the scalar central charge current are shown to be components of a world volume supercurrent. The centrally extended superconformal transformations are realized on the Nambu-Goldstone boson and fermion fields of the non-BPS brane. The superconformal currents form supersymmetry multiplets with the world volume conformal central charge current and special conformal current being the primary components of the supersymmetry multiplets containing all the currents. Correspondingly the superconformal symmetry breaking terms form supersymmetry multiplets the components of which are obtainable as supersymmetry transformations of the primary currents' symmetry breaking terms.Comment: 27 pages, LaTeX, Summary Tables Adde

    Appropriate and inappropriate influences on outpatient discharge decision making in dermatology : a prospective qualitative study

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    © 2015 British Association of Dermatologists.BACKGROUND: Outpatient discharge decision making in dermatology is poorly understood. OBJECTIVE: To identify the influences on clinicians' thought processes when making discharge decisions in dermatology outpatient clinics. METHODS: Forty clinicians from 11 National Health Service Trusts in England were interviewed. The interviews were audiorecorded, transcribed, coded and thematically analysed. RESULTS: The mean age of the clinicians was 48.8 years (range 33.0-67.0), 17 (43%) were men and 19 (48%) had > 20 years of clinical experience. One hundred and forty-eight influences were reported, with five main themes: (i) disease-based influences included type of diagnosis (100% of clinicians), guidelines (100%) and treatment needed (100%); (ii) clinician-based influences included the clinician's level of experience (100%), seniority (37%), emotional attitude (95%), 'gut feeling' (25%), personal attitude towards discharge (45%) and level of perception (100%); (iii) patient-based influences included patients' ability to cope with their disease (100%), wishes (70%), quality of life (32%), command of English (40%) and cultural background (25%); (iv) practice-based influences included good primary care (100%), secondary support structure (100%) and clinic capacity pressure (67%); (v) policy-based influences included pressure from hospital managers (57%) and an active discharge policy (7%). Fourteen (9%) influences were potentially inappropriate. CONCLUSION: This study has identified multiple factors influencing outpatient discharge decision making. This provides the basis for developing evidence-based training to improve discharge decision appropriateness.Peer reviewe

    The gluon and ghost propagators in Euclidean Yang-Mills theory in the maximal Abelian gauge: taking into account the effects of the Gribov copies and of the dimension two condensates

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    The infrared behavior of the gluon and ghost propagators is studied in SU(2) Euclidean Yang-Mills theory in the maximal Abelian gauge within the Gribov-Zwanziger framework. The nonperturbative effects associated with the Gribov copies and with the dimension two condensates are simultaneously encoded into a local and renormalizable Lagrangian. The resulting behavior turns out to be in good agreement with the lattice data.Comment: final version, to appear in Physical Review

    Twisted Superspace for N=D=2 Super BF and Yang-Mills with Dirac-K\"ahler Fermion Mechanism

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    We propose a twisted D=N=2 superspace formalism. The relation between the twisted super charges including the BRST charge, vector and pseudo scalar super charges and the N=2 spinor super charges is established. We claim that this relation is essentially related with the Dirac-K\"ahler fermion mechanism. We show that a fermionic bilinear form of twisted N=2 chiral and anti-chiral superfields is equivalent to the quantized version of BF theory with the Landau type gauge fixing while a bosonic bilinear form leads to the N=2 Wess-Zumino action. We then construct a Yang-Mills action described by the twisted N=2 chiral and vector superfields, and show that the action is equivalent to the twisted version of the D=N=2 super Yang-Mills action, previously obtained from the quantized generalized topological Yang-Mills action with instanton gauge fixing.Comment: 36 page

    Quantum properties of a non-Abelian gauge invariant action with a mass parameter

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    We continue the study of a local, gauge invariant Yang-Mills action containing a mass parameter, which we constructed in a previous paper starting from the nonlocal gauge invariant mass dimension two operator F_{\mu\nu} (D^2)^{-1} F_{\mu\nu}. We return briefly to the renormalizability of the model, which can be proven to all orders of perturbation theory by embedding it in a more general model with a larger symmetry content. We point out the existence of a nilpotent BRST symmetry. Although our action contains extra (anti)commuting tensor fields and coupling constants, we prove that our model in the limit of vanishing mass is equivalent with ordinary massless Yang-Mills theories. The full theory is renormalized explicitly at two loops in the MSbar scheme and all the renormalization group functions are presented. We end with some comments on the potential relevance of this gauge model for the issue of a dynamical gluon mass generation.Comment: 17 pages. v2: version accepted for publication in Phys.Rev.
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