3,271 research outputs found

    A guided search non-dominated sorting genetic algorithm for the multi-objective university course timetabling problem

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    Copyright @ Springer-Verlag Berlin Heidelberg 2011.The university course timetabling problem is a typical combinatorial optimization problem. This paper tackles the multi-objective university course timetabling problem (MOUCTP) and proposes a guided search non-dominated sorting genetic algorithm to solve the MOUCTP. The proposed algorithm integrates a guided search technique, which uses a memory to store useful information extracted from previous good solutions to guide the generation of new solutions, and two local search schemes to enhance its performance for the MOUCTP. The experimental results based on a set of test problems show that the proposed algorithm is efficient for solving the MOUCTP

    Vector bundles on the projective line and finite domination of chain complexes

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    Finitely dominated chain complexes over a Laurent polynomial ring in one indeterminate are characterised by vanishing of their Novikov homology. We present an algebro-geometric approach to this result, based on extension of chain complexes to sheaves on the projective line. We also discuss the K-theoretical obstruction to extension.Comment: v1: 11 page

    Reactivity against Complementary Proteinase-3 Is Not Increased in Patients with PR3-ANCA-Associated Vasculitis

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    The etiology of anti-neutrophil cytoplasmic antibodies (ANCA) associated vasculitides (AAV) is unknown, but the association between infections and autoimmunity has been studied extensively. In 2004, a novel theory was proposed that could link infection and autoimmunity. This ‘theory of autoantigen complementarity’ was based on the serendipitous finding of antibodies against complementary-PR3 (cPR3) in patients with PR3-ANCA-associated vasculitis. cPR3 demonstrated homology to several bacterial proteins, and it was hypothesized that PR3-ANCA develop in response to anti-cPR3 antibodies, as a consequence of the anti-idiotypic network. These data have not been confirmed in other patient cohorts. We investigated the presence of anti-cPR3 antibodies in a Dutch cohort of PR3-ANCA-associated vasculitis patients. Anti-cPR3 reactivity was determined in serum using ELISA. Two separate batches of cPR3 were used to determine reactivity in two separate cohorts of PR3-ANCA-associated vasculitis patients. We found that anti-cPR3-reactivity was not increased in our PR3-ANCA-associated vasculitis patients, in comparison to control groups. Further research will be necessary to prove the concept of autoantigen complementarity in autoimmune diseases

    A quantum analogue of the first fundamental theorem of invariant theory

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    We establish a noncommutative analogue of the first fundamental theorem of classical invariant theory. For each quantum group associated with a classical Lie algebra, we construct a noncommutative associative algebra whose underlying vector space forms a module for the quantum group and whose algebraic structure is preserved by the quantum group action. The subspace of invariants is shown to form a subalgebra, which is finitely generated. We determine generators of this subalgebra of invariants and determine their commutation relations. In each case considered, the noncommutative modules we construct are flat deformations of their classical commutative analogues. Thus by taking the limit as q1q\to 1, our results imply the first fundamental theorem of classical invariant theory, and therefore generalise them to the noncommutative case.Comment: 44 pages, 3 figure

    Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC

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    Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H →γ γ, H → Z Z∗ →4l and H →W W∗ →lνlν. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV, corresponding to an integrated luminosity of about 25 fb−1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined fits probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson

    Standalone vertex finding in the ATLAS muon spectrometer

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    A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at √s = 7 TeV collected with the ATLAS detector at the LHC during 2011

    Measurement of the top quark-pair production cross section with ATLAS in pp collisions at \sqrt{s}=7\TeV

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    A measurement of the production cross-section for top quark pairs(\ttbar) in pppp collisions at \sqrt{s}=7 \TeV is presented using data recorded with the ATLAS detector at the Large Hadron Collider. Events are selected in two different topologies: single lepton (electron ee or muon μ\mu) with large missing transverse energy and at least four jets, and dilepton (eeee, μμ\mu\mu or eμe\mu) with large missing transverse energy and at least two jets. In a data sample of 2.9 pb-1, 37 candidate events are observed in the single-lepton topology and 9 events in the dilepton topology. The corresponding expected backgrounds from non-\ttbar Standard Model processes are estimated using data-driven methods and determined to be 12.2±3.912.2 \pm 3.9 events and 2.5±0.62.5 \pm 0.6 events, respectively. The kinematic properties of the selected events are consistent with SM \ttbar production. The inclusive top quark pair production cross-section is measured to be \sigmattbar=145 \pm 31 ^{+42}_{-27} pb where the first uncertainty is statistical and the second systematic. The measurement agrees with perturbative QCD calculations.Comment: 30 pages plus author list (50 pages total), 9 figures, 11 tables, CERN-PH number and final journal adde

    Measurement of the top quark pair cross section with ATLAS in pp collisions at √s=7 TeV using final states with an electron or a muon and a hadronically decaying τ lepton

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    A measurement of the cross section of top quark pair production in proton-proton collisions recorded with the ATLAS detector at the Large Hadron Collider at a centre-of-mass energy of 7 TeV is reported. The data sample used corresponds to an integrated luminosity of 2.05 fb -1. Events with an isolated electron or muon and a τ lepton decaying hadronically are used. In addition, a large missing transverse momentum and two or more energetic jets are required. At least one of the jets must be identified as originating from a b quark. The measured cross section, σtt-=186±13(stat.)±20(syst.)±7(lumi.) pb, is in good agreement with the Standard Model prediction
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