2,369 research outputs found

    Combination Strategies for Semantic Role Labeling

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    This paper introduces and analyzes a battery of inference models for the problem of semantic role labeling: one based on constraint satisfaction, and several strategies that model the inference as a meta-learning problem using discriminative classifiers. These classifiers are developed with a rich set of novel features that encode proposition and sentence-level information. To our knowledge, this is the first work that: (a) performs a thorough analysis of learning-based inference models for semantic role labeling, and (b) compares several inference strategies in this context. We evaluate the proposed inference strategies in the framework of the CoNLL-2005 shared task using only automatically-generated syntactic information. The extensive experimental evaluation and analysis indicates that all the proposed inference strategies are successful -they all outperform the current best results reported in the CoNLL-2005 evaluation exercise- but each of the proposed approaches has its advantages and disadvantages. Several important traits of a state-of-the-art SRL combination strategy emerge from this analysis: (i) individual models should be combined at the granularity of candidate arguments rather than at the granularity of complete solutions; (ii) the best combination strategy uses an inference model based in learning; and (iii) the learning-based inference benefits from max-margin classifiers and global feedback

    Decomposition of homogeneous polynomials with low rank

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    Let FF be a homogeneous polynomial of degree dd in m+1m+1 variables defined over an algebraically closed field of characteristic zero and suppose that FF belongs to the ss-th secant varieties of the standard Veronese variety Xm,dP(m+dd)1X_{m,d}\subset \mathbb{P}^{{m+d\choose d}-1} but that its minimal decomposition as a sum of dd-th powers of linear forms M1,...,MrM_1, ..., M_r is F=M1d+...+MrdF=M_1^d+... + M_r^d with r>sr>s. We show that if s+r2d+1s+r\leq 2d+1 then such a decomposition of FF can be split in two parts: one of them is made by linear forms that can be written using only two variables, the other part is uniquely determined once one has fixed the first part. We also obtain a uniqueness theorem for the minimal decomposition of FF if the rank is at most dd and a mild condition is satisfied.Comment: final version. Math. Z. (to appear

    Mel silvestre: qualidade para a valorização e competitividade da apicultura no Pantanal.

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    O presente trabalho teve-se o objetivo de avaliar, por meio de análises físico-químicas e sensoriais, a qualidade de 17 amostras de méis silvestres multiflorais de abelhas africanizadas (Apis mellifera L.), produzidos em escala experimental entre 2006 e 2007 na fazenda Nhumirim, Unidade Experimental da Embrapa Pantanal, localizada na sub-região da Nhecolândia do Pantanal, Corumbá-MSbitstream/item/161779/1/BP98.pd

    Premartensitic transition driven by magnetoelastic interaction in bcc ferromagnetic Ni2MnGaNi_{2}MnGa

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    We show that the magnetoelastic coupling between the magnetization and the amplitude of a short wavelength phonon enables the existence of a first order premartensitic transition from a bcc to a micromodulated phase in Ni2MnGaNi_{2}MnGa. Such a magnetoelastic coupling has been experimentally evidenced by AC susceptibility and ultrasonic measurements under applied magnetic field. A latent heat around 9 J/mol has been measured using a highly sensitive calorimeter. This value is in very good agreement with the value predicted by a proposed model.Comment: 4 pages RevTex, 3 Postscript figures, to be published in Physical Review Letter

    La hiperresistència del norovirus

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    Sent una de les malalties més comunes entre la població, la gastroenteritis aguda (GEA) es relaciona habitualment amb els norovirus. Un grup de virus que pot afectar l'estómac i els intestins, i fàcilment transmissibles en espais tancats o per contacte personal, el que explica que habitualment es donin brots epidèmics durant els creuers. Destaquen per la seva capacitat de resistència a pràctiques higièniques o ambients extrems, per la qual cosa es converteixen en una de les primeres causes de malaltia gastrointestinal. Així doncs, el següent article presenta un estudi comparat de les taxes d'afectació per Salmonella i norovirus a Catalunya durant un període de 12 mesos. Els resultats atribueixen a aquest últim una major incidència d'atac i una clara propensió a l'epidèmia, en comparació amb altres agents infecciosos. Per això, proposen unes mesures higienistes més exhaustives.Siendo una de las enfermedades más comunes entre la población, la gastroenteritis aguda (GEA) se relaciona habitualmente con los norovirus. Un grupo de virus que pueden afectar el estómago y los intestinos, y fácilmente transmisibles en espacios cerrados o por contacto personal, lo que explica que habitualmente se den brotes epidémicos durante los cruceros. Destacan por su capacidad de resistencia a prácticas higiénicas o ambientes extremos, por lo que se convierten en una de las primeras causas de enfermedad gastrointestinal. Así pues, el siguiente artículo presenta un estudio comparado de las tasas de afectación por Salmonella y norovirus en Cataluña durante un periodo de 12 meses. Los resultados atribuyen a éste último una mayor incidencia de ataque y una clara propensión a la epidemia, en comparación con otros agentes infecciosos. Por ello, proponen unas medidas higienistas más exhaustivas y dedicar especial atención a los que siempre son los más débiles: ancianos y niños.Acute gastroenteritis (AGE), often related to noroviruses, is one of the most common diseases suffered by the population. Noroviruses affect the stomach and intestines and are easily transmissible through human contact or in enclosed spaces, which would explain why they appear relatively frequently during cruise trips. This group of viruses stands out for its ability to resist good hygiene habits or extreme environments and is one of the main causes of gastrointestinal diseases. The following article presents a comparative study of the index of Salmonella and norovirus cases in Catalonia over a twelve month period. The results show that there is a higher incidence of norovirus attacks and a clear predisposition to cause epidemics when compared to other infectious agencies. Researchers thus propose establishing more exhaustive hygiene measures and that special attention be given to those who always suffer the most: the elderly and children
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