7,384 research outputs found

    A Labeled Graph Kernel for Relationship Extraction

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    In this paper, we propose an approach for Relationship Extraction (RE) based on labeled graph kernels. The kernel we propose is a particularization of a random walk kernel that exploits two properties previously studied in the RE literature: (i) the words between the candidate entities or connecting them in a syntactic representation are particularly likely to carry information regarding the relationship; and (ii) combining information from distinct sources in a kernel may help the RE system make better decisions. We performed experiments on a dataset of protein-protein interactions and the results show that our approach obtains effectiveness values that are comparable with the state-of-the art kernel methods. Moreover, our approach is able to outperform the state-of-the-art kernels when combined with other kernel methods

    The effective Hamiltonian in curved quantum waveguides under mild regularity assumptions

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    The Dirichlet Laplacian in a curved three-dimensional tube built along a spatial (bounded or unbounded) curve is investigated in the limit when the uniform cross-section of the tube diminishes. Both deformations due to bending and twisting of the tube are considered. We show that the Laplacian converges in a norm-resolvent sense to the well known one-dimensional Schroedinger operator whose potential is expressed in terms of the curvature of the reference curve, the twisting angle and a constant measuring the asymmetry of the cross-section. Contrary to previous results, we allow the reference curves to have non-continuous and possibly vanishing curvature. For such curves, the distinguished Frenet frame standardly used to define the tube need not exist and, moreover, the known approaches to prove the result for unbounded tubes do not work. Our main ideas how to establish the norm-resolvent convergence under the minimal regularity assumptions are to use an alternative frame defined by a parallel transport along the curve and a refined smoothing of the curvature via the Steklov approximation.Comment: 29 pages, 6 figure

    The influence of gender and social roles on academic achievement

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    The analysis of the influence of certain social aspects across countries on gender differences in educational achievement has gained a great relevance. In this research the main objective is to deepen into the knowledge of these cultural factors. In order to accomplish this aim, international data from many countries has been used, grouped into education system characteristics, child qualities supported socially, views and opinions on gender roles, and risk-aversion attitudes. The empirical analysis carried out has shown that it is necessary to foster entrepreneurship attitudes during students’ tertiary education, with special emphasis on girls, as they are more affected by gender stereotypes and risk-aversion in comparison to boys. In spite of the existence of unexplained gender differences, individual and country-level factors may have a different effect on the academic achievement of boys and girls.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Brazilian biofuels policies and impacts on world agricultural trade

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    Agricultural and Food Policy, Resource /Energy Economics and Policy,

    The gender gap in educational mismatch: evidence from the Dominican Republic

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    In this paper we test the existence of gender gaps in educational mismatch for a developing country (Dominican Republic), an interesting case study due to its recent policies of education promotion, which achieved an important increase in enrolment rates at all levels of schooling, particularly for women. We use recent microdata to distinguish between over and undereducation, finding asymmetric effects by gender, particularly harmful for women. Various matching techniques based on propensity score methods were implemented in order to evaluate the impact of the over and under education index on earnings.Universidad de MĂĄlaga. Campus de Excelencia Internacional AndalucĂ­a Tech

    Eligibility of External Credit Assessment Institutions

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    The Basel Committee on Banking Supervision in 1999 issued a draft New Basel Capital Accord (Basel 2). Its principles are to be incorporated into the European legislation and into the Czech banking regulations. The Standardised Approach to calculating the capital requirement for credit risk is newly based on external credit assessments (ratings). Banking regulators and supervisors have to be prepared for the process of determining eligible credit assessment institutions (ECAIs) and will have to elaborate a formal recognition procedure. This paper investigates the approaches a supervisor may apply to ECAI recognition and elaborates on the criteria of recognition. First, the paper reviews the available rating agencies on the market (including their rating penetration on the Czech market), their best practices and the experience with the use of their ratings for regulatory purposes. Second, drawing on international experience and the proposed Basel 2 rules, we outline the fundamental supervisory approaches to recognition, including the legal aspects thereof, and analyse their pros and cons and the frontiers of supervisory decision making. Third, we outline the rules for recognition, including requirements or expectations (e.g. soft limits), documentation and typical interview questions with the potential candidates. We find the CNB's approach to be in compliance with CEBS Consultative Paper CP07 (issued for public consultation in June 2005).Basel capital accord, Basel II, Credit rating, default, eligibility criteria, eligibility evaluation, external credit assessment institution (ECAI), export credit agency (ECA), mapping rating grades, market acceptance of ECAIs, rating agency, recognition process

    Distribution of spin-axes longitudes and shape elongations of main-belt asteroids

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    Context: Large all-sky surveys provide us with a lot of photometric data that are sparse in time (typically few measurements per night) and can be potentially used for the determination of shapes and rotational states of asteroids. The method which is generally used to derive these parameters is the lightcurve inversion. However, for most asteroids their sparse data are not accurate enough to derive a unique model and the lightcurve inversion method is thus not very efficient. Aims: To fully utilize photometry sparse in time, we developed a new simplified model and applied it on the data from the Lowell photometric database. Our aim was to derive spin axis orientations and shape elongations of asteroids and to reconstruct distributions of these parameters for selected subpopulations to find if there are some differences. Methods: We model asteroids as geometrically scattering triaxial ellipsoids. Observed values of mean brightness and the dispersion of brightness are compared with computed values obtained from the parameters of the model -- ecliptical longitude λ\lambda and latitude ÎČ\beta of the pole and the ratios a/ba/b, b/cb/c of axes of the ellipsoid. These parameters are optimized to get the best agreement with the observation. Results: We found that the distribution of λ\lambda for main-belt asteroids is not uniform (in agreement with findings of Bowell et al., 2014, M&PS, 49, 95) and is dependent on the inclination of orbit. Surprisingly, the non-uniformity of λ\lambda distribution is larger for asteroids residing on low-inclination orbits. We also studied distributions of a/ba/b for several groups of asteroids and found that small asteroids (D<25 D<25\,km) are on average more elongated than large ones.Comment: 10 pages; Accepted for publication in A&
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