1,244 research outputs found

    Theoretical Analysis of Acceptance Rates in Multigrid Monte Carlo

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    We analyze the kinematics of multigrid Monte Carlo algorithms by investigating acceptance rates for nonlocal Metropolis updates. With the help of a simple criterion we can decide whether or not a multigrid algorithm will have a chance to overcome critial slowing down for a given model. Our method is introduced in the context of spin models. A multigrid Monte Carlo procedure for nonabelian lattice gauge theory is described, and its kinematics is analyzed in detail.Comment: 7 pages, no figures, (talk at LATTICE 92 in Amsterdam

    First human study in treatment of unresectable liver metastases from colorectal cancer with irinotecan-loaded beads (DEBIRI)

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    The objective of this pilot clinical study was to assess the safety, technical feasibility, pharmacokinetic (PK) profile and tumour response of DC Bead™ with irinotecan (DEBIRI™) delivered by intra-arterial embolisation for the treatment of metastatic colorectal cancer. Eleven patients with unresectable liver metastases from CRC, tumour burden <30% of liver volume, adequate haematological, liver and renal function, performance status of <2 were included in this study. Patients received up to 4 sessions of TACE with DEBIRI at 3-week intervals. Feasibility of the procedure, safety and tumour response were assessed after each cycle. PK was measured after the first cycle. Patients were followed up to 24 weeks. Only mild to moderate adverse events were observed. DEBIRI is a technically feasibile procedure; no technical complications were observed. Average Cmax for irinotecan and SN-38 was 194 ng/ml and 16.7 ng/ml, respectively, with average t½ of 4.6 h and 12.4 h following administration of DEBIRI. Best overall response during the study showed disease control in 9 patients (2 patients with partial response and 7 with stable disease, overall response rate of 18%). Our study shows that transarterial chemoembolisation with irinotecan-loaded DC beads (DEBIRI) is safe, technically feasible and effective with a good PK profile

    Multigrid Monte Carlo with higher cycles in the Sine Gordon model

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    We study the dynamical critical behavior of multigrid Monte Carlo for the two dimensional Sine Gordon model on lattices up to 128 x 128. Using piecewise constant interpolation, we perform a W-cycle (gamma=2). We examine whether one can reduce critical slowing down caused by decreasing acceptance rates on large blocks by doing more work on coarser lattices. To this end, we choose a higher cycle with gamma = 4. The results clearly demonstrate that critical slowing down is not reduced in either case.Comment: 7 pages, 1 figure, whole paper including figure contained in ps-file, DESY 93-00

    Cuff overinflation and endotracheal tube obstruction: case report and experimental study

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    Background: Initiated by a clinical case of critical endotracheal tube (ETT) obstruction, we aimed to determine factors that potentially contribute to the development of endotracheal tube obstruction by its inflated cuff. Prehospital climate and storage conditions were simulated. Methods: Five different disposable ETTs (6.0, 7.0, and 8.0 mm inner diameter) were exposed to ambient outside temperature for 13 months. In addition, every second of these tubes was mechanically stressed by clamping its cuffed end between the covers of a metal emergency case for 10 min. Then, all tubes were heated up to normal body temperature, placed within the cock of a syringe, followed by stepwise inflation of their cuffs to pressures of 3 kPa and >=12 kPa, respectively. The inner lumen of the ETT was checked with the naked eye for any obstruction caused by the external cuff pressure. Results: Neither in tubes that were exposed to ambient temperature (range: -12°C to +44°C) nor in those that were also clamped, visible obstruction by inflated cuffs was detected at any of the two cuff pressure levels. Conclusions: We could not demonstrate a critical obstruction of an ETT by its inflated cuff, neither when the cuff was over-inflated to a pressure of 12 kPa or higher, nor in ETTs that had been exposed to unfavorable storage conditions and significant mechanical stress

    Kinematics of Multigrid Monte Carlo

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    We study the kinematics of multigrid Monte Carlo algorithms by means of acceptance rates for nonlocal Metropolis update proposals. An approximation formula for acceptance rates is derived. We present a comparison of different coarse-to-fine interpolation schemes in free field theory, where the formula is exact. The predictions of the approximation formula for several interacting models are well confirmed by Monte Carlo simulations. The following rule is found: For a critical model with fundamental Hamiltonian H(phi), absence of critical slowing down can only be expected if the expansion of in terms of the shift psi contains no relevant (mass) term. We also introduce a multigrid update procedure for nonabelian lattice gauge theory and study the acceptance rates for gauge group SU(2) in four dimensions.Comment: 28 pages, 8 ps-figures, DESY 92-09

    A Sequence of Duals for Sp(2N) Supersymmetric Gauge Theories with Adjoint Matter

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    We consider supersymmetric Sp(2N) gauge theories with F matter fields in the defining representation, one matter field in the adjoint representation, and no superpotential. We construct a sequence of dual descriptions of this theory using the dualities of Seiberg combined with the ``deconfinement'' method introduced by Berkooz. Our duals hint at a new non-perturbative phenomenon that seems to be taking place at asymptotically low energies in these theories: for small F some of the degrees of freedom form massless, non-interacting bound states while the theory remains in an interacting non-Abelian Coulomb phase. This phenomenon is the result of strong coupling gauge dynamics in the original description, but has a simple classical origin in the dual descriptions. The methods used for constructing these duals can be generalized to any model involving arbitrary 2-index tensor representations of Sp(2N), SO(N), or SU(N) groups.Comment: version (with additional references) to appear in Phys. Rev. D, 20 pages, LaTeX, one embedded eps figur

    Incidence, Predictors, and Prognostic Impact of Late Bleeding Complications After Transcatheter Aortic Valve Replacement

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    AbstractBackgroundThe incidence and prognostic impact of late bleeding complications after transcatheter aortic valve replacement (TAVR) are unknown.ObjectivesThe aim of this study was to identify the incidence, predictors, and prognostic impact of major late bleeding complications (MLBCs) (≥30 days) after TAVR.MethodsClinical and echocardiographic outcomes of patients who underwent TAVR within the randomized cohorts and continued access registries in the PARTNER (Placement of Aortic Transcatheter Valves) trial were analyzed after stratifying by the occurrence of MLBCs. Predictors of MLBCs and their association with 30-day to 1-year mortality were assessed.ResultsAmong 2,401 patients who underwent TAVR and survived to 30 days, MLBCs occurred in 142 (5.9%) at a median time of 132 days (interquartile range: 71 to 230 days) after the index procedure. Gastrointestinal complications (n = 58 [40.8%]), neurological complications (n = 22 [15.5%]), and traumatic falls (n = 11 [7.8%]) were identified as the most frequent types of MLBCs. Independent predictors of MLBCs were the presence of low hemoglobin at baseline, atrial fibrillation or flutter at baseline or 30 days, the presence of moderate or severe paravalvular leak at 30 days, and greater left ventricular mass at 30 days. MLBCs were identified as a strong independent predictor of mortality between 30 days and 1 year (adjusted hazard ratio: 3.91; 95% confidence interval: 2.67 to 5.71; p < 0.001).ConclusionsMLBCs after TAVR were frequent and associated with increased mortality. Better individualized and risk-adjusted antithrombotic therapy after TAVR is urgently needed in this high-risk population. (THE PARTNER TRIAL: Placement of AoRTic TraNscathetER Valve Trial; NCT00530894

    Bounds on SCFTs from Conformal Perturbation Theory

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    The operator product expansion (OPE) in 4d (super)conformal field theory is of broad interest, for both formal and phenomenological applications. In this paper, we use conformal perturbation theory to study the OPE of nearly-free fields coupled to SCFTs. Under fairly general assumptions, we show that the OPE of a chiral operator of dimension Δ=1+ϵ\Delta = 1+\epsilon with its complex conjugate always contains an operator of dimension less than 2Δ2 \Delta. Our bounds apply to Banks-Zaks fixed points and their generalizations, as we illustrate using several examples.Comment: 36 pages; v2: typos fixed, minor change

    One case, four approaches: The application of psychotherapeutic approaches in sport psychology.

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    Sport and exercise psychology practitioners tasked with service provision within any environment can decide which framework(s) they draw upon to inform their applied work. However, the similarities and differences between psychotherapeutic approaches are under represented in current literature. Therefore, this paper brings together practitioners from four dominant psychotherapeutic approaches to address one specific hypothetical case. Four different cognitive behavioral approaches are outlined, namely rational emotive behavior therapy (REBT), cognitive therapy (CT), schema therapy (ST), and acceptance and commitment therapy (ACT). Each practitioner outlines their approach and proceeds to address the case by covering assessment, intervention and evaluation strategies that are specific to their approach. Similarities and differences across the approaches are discussed and implications for practice are put forth. Finally, two further practitioners introduce motivational interviewing (MI) as an additional framework to foster the working alliance
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