17,028 research outputs found

    Using Multi-Sense Vector Embeddings for Reverse Dictionaries

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    Popular word embedding methods such as word2vec and GloVe assign a single vector representation to each word, even if a word has multiple distinct meanings. Multi-sense embeddings instead provide different vectors for each sense of a word. However, they typically cannot serve as a drop-in replacement for conventional single-sense embeddings, because the correct sense vector needs to be selected for each word. In this work, we study the effect of multi-sense embeddings on the task of reverse dictionaries. We propose a technique to easily integrate them into an existing neural network architecture using an attention mechanism. Our experiments demonstrate that large improvements can be obtained when employing multi-sense embeddings both in the input sequence as well as for the target representation. An analysis of the sense distributions and of the learned attention is provided as well

    Electromagnetic structure and weak decay of pseudoscalar mesons in a light-front QCD-inspired model

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    We study the scaling of the 3S11S0^3S_1-^1S_0 meson mass splitting and the pseudoscalar weak decay constants with the mass of the meson, as seen in the available experimental data. We use an effective light-front QCD-inspired dynamical model regulated at short-distances to describe the valence component of the pseudoscalar mesons. The experimentally known values of the mass splittings, decay constants (from global lattice-QCD averages) and the pion charge form factor up to 4 [GeV/c]2^2 are reasonably described by the modelComment: 27 Pages, 7 eps figures,use revtex

    Weak decay constant of pseudscalar meson in a QCD-inspired model

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    We show that a linear scaling between the weak decay constants of pseudoscalar and the vector mesons masses is supported by the available experimental data. The decay constant scale as fm/fpi=MV/Mρf_m/f_{pi}=M_V/M_{\rho} (f_m is decay constant and M_V vector meson ground state mass). This simple form is justified within a renormalized light-front QCD-inpired model for quark-antiquark bound states.Comment: 4 pages, use revtex style. To appear "Brazilian Journal of Physics (2003)

    Nonzero orbital angular momentum superfluidity in ultracold Fermi gases

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    We analyze the evolution of superfluidity for nonzero orbital angular momentum channels from the Bardeen-Cooper-Schrieffer (BCS) to the Bose-Einstein condensation (BEC) limit in three dimensions. First, we analyze the low energy scattering properties of finite range interactions for all possible angular momentum channels. Second, we discuss ground state (T=0T = 0) superfluid properties including the order parameter, chemical potential, quasiparticle excitation spectrum, momentum distribution, atomic compressibility, ground state energy and low energy collective excitations. We show that a quantum phase transition occurs for nonzero angular momentum pairing, unlike the s-wave case where the BCS to BEC evolution is just a crossover. Third, we present a gaussian fluctuation theory near the critical temperature (T=TcT = T_{\rm c}), and we analyze the number of bound, scattering and unbound fermions as well as the chemical potential. Finally, we derive the time-dependent Ginzburg-Landau functional near TcT_{\rm c}, and compare the Ginzburg-Landau coherence length with the zero temperature average Cooper pair size.Comment: 28 pages and 24 figure

    Associação micorrízica em plantas nativas da caatinga: ocorrência e eficiência simbiótica para produção de mudas.

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    O objetivo deste trabalho foi ampliar os conhecimentos sobre a associação micorrizica (número de glomerosporos, potencial de infectividade do solo, percentual de colonização e diversidade de FMA) em plantas nativas da caatinga, assim como avaliar o efeito do regime hídrico sobre a reprodução desses fungos

    Resposta de plantas forrageiras à inoculação com fungos micorrízicos arbusculares (FMA) e bactérias fixadoras de nitrogênio (FBN): simbiose e eficiência no crescimento vegetal sob condições semi-áridas.

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    O presente trabalho teve por objetivos avaliar a condição micorrízica no campo das variedades Petrolina e Forrageiro de Cajanus cajan e a eficiência da inoculação com fungos micorrízicos arbusculares (FMA) e BFN no crescimento dessa forrageira em dois tipos de solo
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