Combination Strategies for Semantic Role Labeling

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

INNOVACIÓN COMO CAMBIO INSTITUCIONAL: UNA APROXIMACIÓN DESDE LAS TEORÍAS DE LA COMPLEJIDAD

Uno de los temas más controvertidos dentro de la literatura sobre gestión de la innovación es el grado en que estos procesos son controlables y planificables. Esta literatura ha evolucionado desde una posición racional dentro de la cual los procesos de innovación son el resultado de decisiones racionales, intencionadas y debidamente planificadas, a una posición más evolutiva en la cual si bien no es posible controlar y gestionar el proceso directamente, si que lo es controlar el las condiciones del contexto organizativo de la innovación con objeto de incrementar el éxito del proceso. En este artículo, analizamos el proceso de innovación desde un nuevo paradigma que va más allá de los anteriores y que se fundamenta en los postulados de las teorías de la complejidad y en la asimilación de los procesos de innovación a los procesos de cambio institucional. Desde esta nueva perspectiva, se deduce que los procesos de innovación y el cambio institucional consiguiente tienen una base pragmática y, en consecuencia, el potencial para la planificación y control de los procesos de innovación se ve altamente limitado

North African Jewish and non-Jewish populations form distinctive, orthogonal clusters

Campbell, Christopher L. et al.North African Jews constitute the second largest Jewish Diaspora group. However, their relatedness to each other; to European, Middle Eastern, and other Jewish Diaspora groups; and to their former North African non-Jewish neighbors has not been well defined. Here, genome-wide analysis of five North African Jewish groups (Moroccan, Algerian, Tunisian, Djerban, and Libyan) and comparison with other Jewish and non-Jewish groups demonstrated distinctive North African Jewish population clusters with proximity to other Jewish populations and variable degrees of Middle Eastern, European, and North African admixture. Two major subgroups were identified by principal component, neighbor joining tree, and identity-by-descent analysis - Moroccan/ Algerian and Djerban/Libyan - that varied in their degree of European admixture. These populations showed a high degree of endogamy and were part of a larger Ashkenazi and Sephardic Jewish group. By principal component analysis, these North African groups were orthogonal to contemporary populations from North and South Morocco, Western Sahara, Tunisia, Libya, and Egypt. Thus, this study is compatible with the history of North African Jews - founding during Classical Antiquity with proselytism of local populations, followed by genetic isolation with the rise of Christianity and then Islam, and admixture following the emigration of Sephardic Jews during the Inquisition.This work was supported in part by the Lewis and Rachel Rudin Foundation, the Iranian-American Jewish Federation of New York, the US–Israel Binational Science Foundation, National Institutes of Health Grant 5 U54 CA121852, and Ruth and Sidney Lapidus. L.R.B. and D.C. were supported by Ministerio de Ciencia e Innovación Grant CGL2010-14944/BOS.Peer Reviewe

Tissue discrimination in magnetic resonance imaging of the rator cuff

Evaluation and diagnosis of diseases of the muscles within the rotator cuff can be done using different modalities, being the Magnetic Resonance the method more widely used. There are criteria to evaluate the degree of fat infiltration and muscle atrophy, but these have low accuracy and show great variability inter and intra observer. In this paper, an analysis of the texture features of the rotator cuff muscles is performed to classify them and other tissues. A general supervised classification approach was used, combining forward-search as feature selection method with kNN as classification rule. Sections of Magnetic Resonance Images of the tissues of interest were selected by specialist doctors and they were considered as Gold Standard. Accuracies obtained were of 93% for T1-weighted images and 92% for T2-weighted images. As an immediate future work, the combination of both sequences of images will be considered, expecting to improve the results, as well as the use of other sequences of Magnetic Resonance Images. This work represents an initial point for the classification and quantification of fat infiltration and muscle atrophy degree. From this initial point, it is expected to make an accurate and objective system which will result in benefits for future research and for patients' health

Decomposition of homogeneous polynomials with low rank

Let $F$ be a homogeneous polynomial of degree $d$ in $m+1$ variables defined over an algebraically closed field of characteristic zero and suppose that $F$ belongs to the $s$-th secant varieties of the standard Veronese variety $X_{m,d}\subset \mathbb{P}^{{m+d\choose d}-1}$ but that its minimal decomposition as a sum of $d$-th powers of linear forms $M_1, ..., M_r$ is $F=M_1^d+... + M_r^d$ with $r>s$. We show that if $s+r\leq 2d+1$ then such a decomposition of $F$ 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 $F$ if the rank is at most $d$ and a mild condition is satisfied.Comment: final version. Math. Z. (to appear

La hiperresistència del norovirus

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