13,779 research outputs found
Using Multi-Sense Vector Embeddings for Reverse Dictionaries
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
We study the scaling of the 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] are reasonably described by the modelComment: 27 Pages, 7 eps figures,use revtex
Weak decay constant of pseudscalar meson in a QCD-inspired model
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 (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
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 () 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 (),
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 , 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.
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
Phase Fluctuations and Vortex Lattice Melting in Triplet Quasi-One-Dimensional Superconductors at High Magnetic Fields
Assuming that the order parameter corresponds to an equal spin triplet
pairing symmetry state, we calculate the effect of phase fluctuations in
quasi-one-dimensional superconductors at high magnetic fields applied along the
y (b') axis. We show that phase fluctuations can destroy the theoretically
predicted triplet reentrant superconducting state, and that they are
responsible for melting the magnetic field induced Josephson vortex lattice
above a magnetic field dependent melting temperature Tm.Comment: 4 pages (double column), 1 eps figur
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.
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
Fungos micorrízicos arbusculares (FMA) e rizobactérias promotoras de crescimento de plantas (RPCP) na aclimatização de Zingiber spectabile Griff. micropropagado (Zingiberaceae).
O objetivo do trabalho foi avaliar o potencial de FMA e RPCP, isolados e/ou combinados (em dupla inoculação) na aclimatização de Z. spectabi/e
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