1,452 research outputs found

    Two-loop electroweak top corrections: are they under control?

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    The assumption that two-loop top corrections are well approximated by the O(Gmu2mt4)O(G_mu^2 mt^4) contribution is investigated. It is shown that in the case of the ratio neutral-to-charged current amplitudes at zero momentum transfer the O(Gmu2mt2MZ2)O(G_mu^2 mt^2 M_Z^2) terms are numerically comparable to the mt4m_t^4 contribution for realistic values of the top mass. An estimate of the theoretical error due to unknown two-loop top effect is presented for a few observables of LEP interest.Comment: 13 pages, LaTeX using equations, doublespace, cite macros. Hard copies of the paper including one figure are available from [email protected]

    POD-Based reduced order methods for optimal control problems governed by parametric partial differential equation with varying boundary control

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    In this work we propose tailored model order reduction for varying boundary optimal con-trol problems governed by parametric partial differential equations. With varying boundary control, we mean that a specific parameter changes where the boundary control acts on the system. This peculiar formulation might benefit from model order reduction. Indeed, fast and reliable simulations of this model can be of utmost usefulness in many applied fields, such as geophysics and energy engineering. However, varying boundary control features very complicated and diversified parametric behaviour for the state and adjoint variables. The state solution, for example, changing the boundary control parameter, might feature transport phenomena. Moreover, the problem loses its affine structure. It is well known that classical model order reduction techniques fail in this setting, both in accuracy and in efficiency. Thus, we propose reduced approaches inspired by the ones used when dealing with wave-like phenomena. Indeed, we compare standard proper orthogonal decomposi-tion with two tailored strategies: geometric recasting and local proper orthogonal decom-position. Geometric recasting solves the optimization system in a reference domain simpli-fying the problem at hand avoiding hyper-reduction, while local proper orthogonal decom-position builds local bases to increase the accuracy of the reduced solution in very general settings (where geometric recasting is unfeasible). We compare the various approaches on two different numerical experiments based on geometries of increasing complexity.& COPY; 2023 Elsevier Inc. All rights reserved

    Fermion Virtual Effects in e+e−−>W+W−e^+ e^- -> W^+ W^- Cross Section

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    We analyse the contribution of new heavy virtual fermions to the e+e−→W+W−e^+e^- \rightarrow W^+W^- cross section. We find that there exists a relevant interplay between trilinear and bilinear oblique corrections. The result strongly depends on the chiral or vector--like nature of the new fermions. As for the chiral case we consider sequential fermions: one obtains substantial deviation from the Standard model prediction, making the effect possibly detectable at s=500\sqrt{s}=500 or 10001000 GeV linear colliders. As an example for the vector--like case we take a SUSY extension with heavy charginos and neutralinos: due to cancellation, the final effect turns out to be negligible.Comment: uuencoded, gz-compressed, tar-ed file. 8 pages, 4 EPS figures, uses EPSFIG.ST

    Nasal pathologies in patients with obstructive sleep apnoea

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    Nasal obstruction is a frequent condition in patients with obstructive sleep apnoea (OSA). Nasal obstruction leads to mouth breathing, which is thought to destabilise the upper airway to aggravate the condition. Three conditions could be considered as the cause of the nasal breathing obstruction: anatomical conditions of the nose (septum deviation, hypertrophy of the inferior turbinates), chronic rhinosinusitis (CRS) and chronic nasal inflammation caused by allergic rhinitis or non-allergic cellular rhinitis. In this prospective study, we present an evaluation of all these possible rhino-sinusal aspects in OSA patients to correlate different nasal pathologies with nasal obstruction. Fifty patients with a diagnosis of OSA were enrolled in the study. In 70% of OSA patients, nasal obstruction was confirmed by clinical evaluation and rhinomanometry testing. Normal rhino-sinus aspects were present in only 20% of OSAS patients, whereas one or more pathological rhino-sinus conditions were present in the remaining 80%. The percentage of OSA patients with a diagnosis of allergic rhinitis and non-allergic rhinitis was 18% and 26% respectively. Non-allergic rhinitis with neutrophils (NARNE) was the most frequent type of cellular rhinitis diagnosed in OSA patients (20% of cases). The results of the present study support and extend the observation that rhinitis is present in OSA patients. Mucosal inflammation caused by these conditions could be the cause of upper airway patency impairment inducing nasal mucosa swellin

    Theory Building as Integrated Reflection: Understanding Physician Reflection Through Human Communication Research, Medical Education, and Ethics

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    Grounded in a presupposition that a single explanatory framework cannot fully account for the expansive learning processes that occur during medical residency, the article examines developing physicians’ reflective writing from three disciplinary lenses. The goal is to understand how the multi-dimensional nature of medical residency translates into assembling educational experiences and constructing meaning that cannot be fully explained through a single discipline. An interdisciplinary research team across medical education, communication, and ethics qualitatively analyzed reflective entries (N=756) completed by family medicine residents (N=33) across an academic year. Results provide evidence for moving toward an integrated thematic explanation across disciplines. The authors suggest that the integration of disciplinary explanations allows for comprehensive understanding of reflection as a cornerstone in the broader formation of the physician. Examples provide evidence for an integrated understanding of a fuller human experience by considering the three thematic explanations as co-occurring, reciprocal processes

    APENet: LQCD clusters a la APE

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    Developed by the APE group, APENet is a new high speed, low latency, 3-dimensional interconnect architecture optimized for PC clusters running LQCD-like numerical applications. The hardware implementation is based on a single PCI-X 133MHz network interface card hosting six indipendent bi-directional channels with a peak bandwidth of 676 MB/s each direction. We discuss preliminary benchmark results showing exciting performances similar or better than those found in high-end commercial network systems.Comment: Lattice2004(machines), 3 pages, 4 figure

    Testosterone insulin-like effects: an in vitro study on the short-term metabolic effects of testosterone in human skeletal muscle cells

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    Testosterone by promoting different metabolic pathways contributes to short-term homeostasis of skeletal muscle, the largest insulin-sensitive tissue and the primary site for insulin-stimulated glucose utilization. Despite evidences indicate a close relationship between testosterone and glucose metabolism, the molecular mechanisms responsible for a possible testosterone-mediated insulin-like effects on skeletal muscle are still unknown

    NNLO QCD×EW corrections to Z production in the q q channel

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    We present the first results for the O(ααs) corrections to the total partonic cross section of the process qq→Z+X, with the complete set of contributions, that include photonic and massive weak gauge boson effects. The results are relevant for the precise determination of the hadronic Z boson production cross section. Virtual and real corrections are calculated analytically using the reduction to the master integrals and their evaluation through differential equations. Real corrections are dealt with using the reverse-unitarity method. They require the evaluation of a new set of two-loop master integrals, with up to three internal massive lines. In particular, three of them are expressed in terms of elliptic integrals. We verify the absence, at this perturbative order, of initial-state mass singularities proportional to a weak massive virtual correction to the quark-gluon splitting

    Vacuum Condensates and Dynamical Mass Generation in Euclidean Yang-Mills Theories

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    Vacuum condensates of dimension two and their relevance for the dynamical mass generation for gluons in Yang-Mills theories are discussedComment: Talk given at the International Conference on Color Confinement and Hadrons in Quantum Chromodynamics, Confinement 2003, TITech and RIKEN, Tokyo, Japan, July 21-24, 200
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