1,036 research outputs found

    Comment on "Origin of cosmic magnetic fields"

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    We argue that the result presented in "Origin of cosmic magnetic fields" by L. Campanelli [arXiv:1304.6534] is unphysical.Comment: 1 page, 1 figure. Typos fixed, minor corrections, a comment added, version published in PR

    Neutron Transverse-Momentum Distributions and Polarized 3He within Light-Front Hamiltonian Dynamics

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    The possibility to extract the quark transverse-momentum distributions in the neutron from semi-inclusive deep inelastic electron scattering off polarized 3He is illustrated through an impulse approximation analysis in the Bjorken limit. The generalization of the analysis at finite momentum transfers in a Poincare' covariant framework is outlined. The definition of the light-front spin-dependent spectral function of a J=1/2 system allows us to show that within the light-front dynamics only three of the six leading twist T-even transverse-momentum distributions are independent.Comment: 4 pages, 2 figures, Presented at the 20th International IUPAP Conference on Few-Body Problems in Physics, 20 - 25 August, 2012, Fukuoka, Japa

    Safety and Efficacy of Perampanel as Adjunctive Therapy in Patients with Refractory Focal Epilepsy Over 12 Months: Clinical Experience in a Real-World Setting

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    Abstract Background The main purpose of this study is to assess efficacy and tolerability of perampanel (PER), a noncompetitive őĪ-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor antagonist, as an add-on treatment in adult patients with refractory focal-onset seizures. Patients and Methods A prospective, open label, observational study was conducted in patients with refractory focal-onset seizures treated with PER at our Epilepsy Unit, from May 2015 to February 2016. Patients were followed up for 1 year. Frequency of seizure and tolerability was assessed every 3 months. Patients were under a polytherapy, and the mean number of concomitant antiepileptic drugs (AEDs) at PER initiation was 2.9. Results We consecutively enrolled 52 patients (M/F = 18/34). Three were lost on follow-up. Mean age was 38.7 years, with a mean duration of disease of 28.1 years. After 1 year of treatment, 57.14% reported a 50% or greater reduction in seizure frequency; five (10.21%) were seizure free. Six (12.25%) patients reported a reduction lower than 50%. Mean dosage of PER was 7.57 mg. Thirty-one patients were taking enzyme-inducing AEDs (carbamazepine, oxcarbazepine, phenytoin). In this subgroup, the responder rate was 45.2%. Twenty-one patients reported side-effects, most frequently somnolence (11), vertigo/ataxia (6), and aggressiveness (5). Eleven (22.4%) patients reduced or discontinued at least one concomitant AED, while the electroencephalography improved in four (8.16%). Sixteen (32.65%) patients withdrew PER, after a mean duration of 163 days, the mean dosage being 6.4 mg (range 4‚Äď12). Conclusions Adjunctive PER can achieve clinically meaningful improvement, or even seizure freedom, in almost two-thirds of patients suffering from refractory focal-onset epilepsies. It seems similarly safe and well-tolerated. Enzyme-inducing AEDs may limit the efficacy of PER

    Minimizing Breaks by Maximizing Cuts

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    Jean Charles Régin and Michael Trick have proposed to solve the schedule generation problem for sports leagues in two phases in which the first generates a tournament schedule and the second fixes the home-away pattern so as to minimize the number of breaks. While constraint programming techniques appear to be the methods of choice for the first phase, we propose to solve the break minimization problem in sports scheduling by transforming it into a maximum cut problem in an undirected graph and applying a branch-and-cut algorithm. Our approach outperforms previous approaches with constraint programming and integer programming techniques

    Minimizing Breaks by Maximizing Cuts

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    Jean Charles Régin and Michael Trick have proposed to solve the schedule generation problem for sports leagues in two phases in which the first generates a tournament schedule and the second fixes the home-away pattern so as to minimize the number of breaks. While constraint programming techniques appear to be the methods of choice for the first phase, we propose to solve the break minimization problem in sports scheduling by transforming it into a maximum cut problem in an undirected graph and applying a branch-and-cut algorithm. Our approach outperforms previous approaches with constraint programming and integer programming techniques

    The Traveling Salesman Problem

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    This paper presents a self-contained introduction into algorithmic and computational aspects of the traveling salesman problem and of related problems, along with their theoretical prerequisites as seen from the point of view of an operations researcher who wants to solve practical problem instances. Extensive computational results are reported on most of the algorithms described. Optimal solutions are reported for instances with sizes up to several thousand nodes as well as heuristic solutions with provably very high quality for larger instances

    Practical Performance of Efficient Minimum Cut Algorithms

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    In the late eighties and early nineties, three major exciting new developments (and some ramifications) in the computation of minimum capacity cuts occurred and these developments motivated us to evaluate the old and new methods experimentally. We provide a brief overview of the most important algorithms for the minimum capacity cut problem and compare these methods both on problem instances from the literature and on problem instances originating from the solution of the traveling salesman problem by branch-and-cut

    Optimal patchings for consecutive ones matrices

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    AbstractWe study a variant of the weighted consecutive ones property problem. Here, a 0/1-matrix is given with a cost associated to each of its entries and one has to find a minimum cost set of zero entries to be turned to ones in order to make the matrix have the consecutive ones property for rows. We investigate polyhedral and combinatorial properties of the problem and we exploit them in a branch-and-cut algorithm. In particular, we devise preprocessing rules and investigate variants of "local cuts". We test the resulting algorithm on a number of instances, and we report on these computational experiments
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