651 research outputs found

    Theta dependence of CP^9 model

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    We apply to the CP9CP^9 model two recently proposed numerical techniques for simulation of systems with a theta term. The algorithms, successfully tested in the strong coupling limit, are applied to the weak coupling region. The results agree and errors have been evaluated and are at % level. The results scale well with the renormalization group equation and show that, for CP9CP^9 in presence of a theta term, CP symmetry is spontaneously broken at θ=π\theta=\pi in the continuum limit.Comment: 4 pages, 4 figure

    Job Retention and Reintegration in People with Mental Health Problems: A Descriptive Evaluation of Supported Employment Routine Programs.

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    PURPOSE Striking evidence supports the effectiveness of supported employment (SE) in achieving competitive employment in individuals with mental health problems. Yet, little is known whether SE is effective to maintain employment in individuals at risk of job loss. We aimed to descriptively compare SE for employed clients (SE-retention) and unemployed clients (SE-integration) regarding competitive employment. METHODS We used administrative data from January 2017 to October 2021 provided by a vocational rehabilitation center in Switzerland including all individuals (≥ 18yrs.) with mental health problems who participated either in SE-retention or SE-reintegration. The outcome was the proportion with competitive employment at discharge. Logistic regression was used to assess time trends and to descriptively compare SE-treatments. We used propensity score weighting, including personal, clinical and program-specific information to reduce group differences. RESULTS A total of 556 participants primarily diagnosed with mood/stress-related, schizophrenia and personality disorders were included (n = 297 SE-retention, n = 259 SE-reintegration) with median age 41 years and 57% female gender. The overall weighted comparison favored SE-retention over SE-reintegration OR 4.85 (95%-CI 3.10 to 7.58, p < 0.001) with predicted employment of 67.3% and 29.9% for SE-retention and SE-reintegration, respectively. While success for SE-reintegration remained stable over time, SE-retention showed an increase in more recent years. CONCLUSION SE-retention provides an approach for early work-related support that can prevent labor market exclusion. In contrast, reintegration is likely to require more efforts to achieve employment and may result in less favorable outcomes. It is therefore necessary that further research includes appropriate comparison groups to evaluate the effectiveness of SE-retention programs as well as the economic and individual benefits

    Brain-derived neurotrophic factor stimulates energy metabolism in developing cortical neurons.

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    Brain-derived neurotrophic factor (BDNF) promotes the biochemical and morphological differentiation of selective populations of neurons during development. In this study we examined the energy requirements associated with the effects of BDNF on neuronal differentiation. Because glucose is the preferred energy substrate in the brain, the effect of BDNF on glucose utilization was investigated in developing cortical neurons via biochemical and imaging studies. Results revealed that BDNF increases glucose utilization and the expression of the neuronal glucose transporter GLUT3. Stimulation of glucose utilization by BDNF was shown to result from the activation of Na+/K+-ATPase via an increase in Na+ influx that is mediated, at least in part, by the stimulation of Na+-dependent amino acid transport. The increased Na+-dependent amino acid uptake by BDNF is followed by an enhancement of overall protein synthesis associated with the differentiation of cortical neurons. Together, these data demonstrate the ability of BDNF to stimulate glucose utilization in response to an enhanced energy demand resulting from increases in amino acid uptake and protein synthesis associated with the promotion of neuronal differentiation by BDNF

    Perfect Lattice Topology: The Quantum Rotor as a Test Case

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    Lattice actions and topological charges that are classically and quantum mechanically perfect (i.e. free of lattice artifacts) are constructed analytically for the quantum rotor. It is demonstrated that the Manton action is classically perfect while the Villain action is quantum perfect. The geometric construction for the topological charge is only perfect at the classical level. The quantum perfect lattice topology associates a topological charge distribution, not just a single charge, with each lattice field configuration. For the quantum rotor with the classically perfect action and topological charge, the remaining cut-off effects are exponentially suppressed.Comment: 12 pages, including two figures. ordinary LaTeX, requires fps.sty; Submitted to Phys. Lett.

    Early complications after living donor nephrectomy: analysis of the Swiss Organ Living Donor Health Registry.

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    We evaluated the prospectively collected data about the incidence of early peri- and postoperative complications, and potential risk factors for adverse outcomes after living kidney donation in Switzerland. Peri- and postoperative events were prospectively recorded on a questionnaire by the local transplant teams of all Swiss transplant centres and evaluated by the Swiss Organ Living Donor Health Registry. Complications were classified according to the Clavien grading system. A total of 1649 consecutive donors between 1998 and 2015 were included in the analysis. There was no perioperative mortality observed. The overall complication rate was 13.5%. Major complications defined as Clavien ≥3 occurred in 2.1% of donors. Obesity was not associated with any complications. Donor age &gt;70years was associated with major complications (odds ratio [OR] 3.99) and genitourinary complications (urinary tract infection OR 5.85; urinary retention OR 6.61). There were more major complications observed in donors with laparoscopic surgery versus open surgery (p = 0.048), but an equal overall complication rate (p = 0.094). We found a low rate of major and minor complications, independent of surgical technique, after living donor nephrectomy. There was no elevated complication rate in obese donors. In contrast, elderly donors &gt;70 years had an elevated risk for perioperative complications

    Current Dyspnea Among Long-Term Survivors of Early-Stage Non-small Cell Lung Cancer

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    IntroductionDyspnea is common among lung cancer patients. As most studies of dyspnea have reviewed patients with active cancer or immediately after treatment, its prevalence during the longer-term period once treatment has been completed is not well characterized. This study quantifies the prevalence of dyspnea among lung cancer survivors and identifies potential correlates that may be amenable to intervention.MethodsCross-sectional survey of 342 patients with disease-free, stage I, non-small cell lung cancer, assessed 1 to 6 years after surgical resection. Dyspnea was quantified using the Baseline Dyspnea Index. Any moderate/strenuous physical activity was measured using the Godin Leisure-Time Exercise Questionnaire. Mood disorder symptoms were assessed using the Hospital Anxiety and Depression Scale. Multiple regression analyses were used to examine demographic, medical, and health-related correlates of dyspnea.ResultsMean age was 68.9 years. Average predicted preoperative forced expiratory volume in 1 second was 89.0%. Current dyspnea, defined by a Baseline Dyspnea Index score of 9 or less, existed among 205 (60%) individuals. For 133 (65%) of these patients, dyspnea was absent preoperatively. Multivariate correlates of current dyspnea included preoperative dyspnea (odds ratio [OR] = 5.31), preoperative diffusing capacity (OR = 0.98), lack of moderate/strenuous physical activity (OR = 0.41), and the presence of clinically significant depression symptoms (OR = 4.10).ConclusionsDyspnea is common 1 to 6 years after lung cancer resection, and is associated with the presence of preoperative dyspnea, reduced diffusing capacity, clinically significant depression symptoms, and lack of physical activity. Further research is needed to test whether strategies that identify and treat patients with these conditions attenuate dyspnea among lung cancer survivors

    Quenched divergences in the deconfined phase of SU(2) gauge theory

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    The spectrum of the overlap Dirac operator in the deconfined phase of quenched gauge theory is known to have three parts: exact zeros arising from topology, small nonzero eigenvalues that result in a non-zero chiral condensate, and the dense bulk of the spectrum, which is separated from the small eigenvalues by a gap. In this paper, we focus on the small nonzero eigenvalues in an SU(2) gauge field background at β=2.4\beta=2.4 and NT=4N_T=4. This low-lying spectrum is computed on four different spatial lattices (12312^3, 14314^3, 16316^3, and 18318^3). As the volume increases, the small eigenvalues become increasingly concentrated near zero in such a way as to strongly suggest that the infinite volume condensate diverges.Comment: 12 pages, 3 figures, version to appear in Physical Review

    Boundary Limitation of Wavenumbers in Taylor-Vortex Flow

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    We report experimental results for a boundary-mediated wavenumber-adjustment mechanism and for a boundary-limited wavenumber-band of Taylor-vortex flow (TVF). The system consists of fluid contained between two concentric cylinders with the inner one rotating at an angular frequency Ω\Omega. As observed previously, the Eckhaus instability (a bulk instability) is observed and limits the stable wavenumber band when the system is terminated axially by two rigid, non-rotating plates. The band width is then of order ϵ1/2\epsilon^{1/2} at small ϵ\epsilon (ϵΩ/Ωc1\epsilon \equiv \Omega/\Omega_c - 1) and agrees well with calculations based on the equations of motion over a wide ϵ\epsilon-range. When the cylinder axis is vertical and the upper liquid surface is free (i.e. an air-liquid interface), vortices can be generated or expelled at the free surface because there the phase of the structure is only weakly pinned. The band of wavenumbers over which Taylor-vortex flow exists is then more narrow than the stable band limited by the Eckhaus instability. At small ϵ\epsilon the boundary-mediated band-width is linear in ϵ\epsilon. These results are qualitatively consistent with theoretical predictions, but to our knowledge a quantitative calculation for TVF with a free surface does not exist.Comment: 8 pages incl. 9 eps figures bitmap version of Fig

    Calculation of Non-Leptonic Kaon Decay Amplitudes from KπK\to\pi Matrix Elements in Quenched Domain-Wall QCD

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    We explore application of the domain wall fermion formalism of lattice QCD to calculate the KππK\to\pi\pi decay amplitudes in terms of the KπK\to\pi and K0K\to 0 hadronic matrix elements through relations derived in chiral perturbation theory. Numerical simulations are carried out in quenched QCD using domain-wall fermion action for quarks and an RG-improved gauge action for gluons on a 163×32×1616^3\times 32\times 16 and 243×32×1624^3\times 32\times 16 lattice at β=2.6\beta=2.6 corresponding to the lattice spacing 1/a21/a\approx 2GeV. Quark loop contractions which appear in Penguin diagrams are calculated by the random noise method, and the ΔI=1/2\Delta I=1/2 matrix elements which require subtractions with the quark loop contractions are obtained with a statistical accuracy of about 10%. We confirm the chiral properties required of the KπK\to\pi matrix elements. Matching the lattice matrix elements to those in the continuum at μ=1/a\mu=1/a using the perturbative renormalization factor to one loop order, and running to the scale μ=mc=1.3\mu=m_c=1.3 GeV with the renormalization group for Nf=3N_f=3 flavors, we calculate all the matrix elements needed for the decay amplitudes. With these matrix elements, the ΔI=3/2\Delta I=3/2 decay amplitude shows a good agreement with experiment in the chiral limit. The ΔI=1/2\Delta I=1/2 amplitude, on the other hand, is about 50--60% of the experimental one even after chiral extrapolation. In view ofthe insufficient enhancement of the ΔI=1/2\Delta I=1/2 contribution, we employ the experimental values for the real parts of the decay amplitudes in our calculation of ϵ/ϵ\epsilon'/\epsilon. We find that the ΔI=3/2\Delta I=3/2 contribution is larger than the ΔI=1/2\Delta I=1/2 contribution so that ϵ/ϵ\epsilon'/\epsilon is negative and has a magnitude of order 10410^{-4}. Possible reasons for these unsatisfactory results are discussed.Comment: 48 pages, final version to appear in Physical Review

    Efficient Cluster Algorithm for CP(N-1) Models

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    Despite several attempts, no efficient cluster algorithm has been constructed for CP(N-1) models in the standard Wilson formulation of lattice field theory. In fact, there is a no-go theorem that prevents the construction of an efficient Wolff-type embedding algorithm. In this paper, we construct an efficient cluster algorithm for ferromagnetic SU(N)-symmetric quantum spin systems. Such systems provide a regularization for CP(N-1) models in the framework of D-theory. We present detailed studies of the autocorrelations and find a dynamical critical exponent that is consistent with z = 0.Comment: 14 pages, 3 figure
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