3,601 research outputs found

    Another look at anomalous J/Psi suppression in Pb+Pb collisions at P/A = 158 GeV/c

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    A new data presentation is proposed to consider anomalous J/ΨJ/\Psi suppression in Pb + Pb collisions at P/A=158P/A=158 GeV/c. If the inclusive differential cross section with respect to a centrality variable is available, one can plot the yield of J/Psi events per Pb-Pb collision as a function of an estimated squared impact parameter. Both quantities are raw experimental data and have a clear physical meaning. As compared to the usual J/Psi over Drell-Yan ratio, there is a huge gain in statistical accuracy. This presentation could be applied advantageously to many processes in the field of nucleus-nucleus collisions at various energies.Comment: 6 pages, 5 figures, submitted to The European Physical Journal C; minor revisions for final versio

    Organization of pre-Variscan basement areas at the north-Gondwanan margin

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    Pre-Variscan basement elements of Central Europe appear in polymetamorphic domains juxtaposed through Variscan and/or Alpine tectonic events. Consequently, nomenclatures and zonations applied to Variscan and Alpine structures, respectively, cannot be valid for pre-Variscan structures. Comparing pre-Variscan relics hidden in the Variscan basement areas of Central Europe, the Alps included, large parallels between the evolution of basement areas of future Avalonia and its former peri-Gondwanan eastern prolongations (e.g. Cadomia, Intra-Alpine Terrane) become evident. Their plate-tectonic evolution from the Late Proterozoic to the Late Ordovician is interpreted as a continuous Gondwana-directed evolution. Cadomian basement, late Cadomian granitoids, late Proterozoic detrital sediments and active margin settings characterize the pre-Cambrian evolution of most of the Gondwana-derived microcontinental pieces. Also the Rheic ocean, separating Avalonia from Gondwana, should have had, at its early stages, a lateral continuation in the former eastern prolongation of peri-Gondwanan microcontinents (e.g. Cadomia, Intra-Alpine Terrane). Subduction of oceanic ridge (Proto-Tethys) triggered the break-off of Avalonia, whereas in the eastern prolongation, the presence of the ridge may have triggered the amalgamation of volcanic arcs and continental ribbons with Gondwana (Ordovician orogenic event). Renewed Gondwana-directed subduction led to the opening of Palaeo-Tethy

    Automorphism groups of polycyclic-by-finite groups and arithmetic groups

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    We show that the outer automorphism group of a polycyclic-by-finite group is an arithmetic group. This result follows from a detailed structural analysis of the automorphism groups of such groups. We use an extended version of the theory of the algebraic hull functor initiated by Mostow. We thus make applicable refined methods from the theory of algebraic and arithmetic groups. We also construct examples of polycyclic-by-finite groups which have an automorphism group which does not contain an arithmetic group of finite index. Finally we discuss applications of our results to the groups of homotopy self-equivalences of K(\Gamma, 1)-spaces and obtain an extension of arithmeticity results of Sullivan in rational homotopy theory

    Ideals of Quasi-Symmetric Functions and Super-Covariant Polynomials for S_n

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    The aim of this work is to study the quotient ring R_n of the ring Q[x_1,...,x_n] over the ideal J_n generated by non-constant homogeneous quasi-symmetric functions. We prove here that the dimension of R_n is given by C_n, the n-th Catalan number. This is also the dimension of the space SH_n of super-covariant polynomials, that is defined as the orthogonal complement of J_n with respect to a given scalar product. We construct a basis for R_n whose elements are naturally indexed by Dyck paths. This allows us to understand the Hilbert series of SH_n in terms of number of Dyck paths with a given number of factors.Comment: LaTeX, 3 figures, 12 page

    Conjugacy theorems for loop reductive group schemes and Lie algebras

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    The conjugacy of split Cartan subalgebras in the finite dimensional simple case (Chevalley) and in the symmetrizable Kac-Moody case (Peterson-Kac) are fundamental results of the theory of Lie algebras. Among the Kac-Moody Lie algebras the affine algebras stand out. This paper deals with the problem of conjugacy for a class of algebras --extended affine Lie algebras-- that are in a precise sense higher nullity analogues of the affine algebras. Unlike the methods used by Peterson-Kac, our approach is entirely cohomological and geometric. It is deeply rooted on the theory of reductive group schemes developed by Demazure and Grothendieck, and on the work of J. Tits on buildingsComment: Publi\'e dans Bulletin of Mathematical Sciences 4 (2014), 281-32

    Análise genética do início do florescimento em feijoeiro pelo "Triple Test Cross".

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    objetivo deste trabalho foi detectar a presença de epistasia e estimar os componentes da variância genética para o caráter início do florescimento em populações de feijoeiro (Phaseolus vulgaris L.) oriundas de genitores de diferentes conjuntos gênicos (pools gênicos)

    Componentes da variância genética no cruzamento de feijões andinos e mesoamericanos.

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    Quando os cruzamentos são viáveis, frequentemente a população obtida apresenta desempenho abaixo da média dos pais para produtividade de grãos. Entretanto a partir do cruzamento entre as linhagens ESAL 686 (Andina) e Carioca MG (Mesoamericana) foram obtidas linhagens com bom desempenho (BRUZI et al., 2007). Seria importante estimar os componentes da variância genética e fenotípica desse cruzamento a fim de verificar se a variabilidade obtida é diferente do que é normalmente observado em outros cruzamentos de feijoeiro do mesmo conjunto gênico.CONAFE

    Potencial de populações segregantes de feijoeiro oriundas de cruzamentos intra e inter conjuntos gênicos.

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    Esse trabalho teve como objetivo comparar o potencial de populações segregantes de feijoeiro oriundas do cruzamento de genitores de mesmo conjunto gênico e de conjuntos gênicos diferentes por meio de estimativas de alguns parâmetros genéticos e fenotípicos
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