Graph edit distance from spectral seriation

This paper is concerned with computing graph edit distance. One of the criticisms that can be leveled at existing methods for computing graph edit distance is that they lack some of the formality and rigor of the computation of string edit distance. Hence, our aim is to convert graphs to string sequences so that string matching techniques can be used. To do this, we use a graph spectral seriation method to convert the adjacency matrix into a string or sequence order. We show how the serial ordering can be established using the leading eigenvector of the graph adjacency matrix. We pose the problem of graph-matching as a maximum a posteriori probability (MAP) alignment of the seriation sequences for pairs of graphs. This treatment leads to an expression in which the edit cost is the negative logarithm of the a posteriori sequence alignment probability. We compute the edit distance by finding the sequence of string edit operations which minimizes the cost of the path traversing the edit lattice. The edit costs are determined by the components of the leading eigenvectors of the adjacency matrix and by the edge densities of the graphs being matched. We demonstrate the utility of the edit distance on a number of graph clustering problems

A graph-spectral approach to shape-from-shading

In this paper, we explore how graph-spectral methods can be used to develop a new shape-from-shading algorithm. We characterize the field of surface normals using a weight matrix whose elements are computed from the sectional curvature between different image locations and penalize large changes in surface normal direction. Modeling the blocks of the weight matrix as distinct surface patches, we use a graph seriation method to find a surface integration path that maximizes the sum of curvature-dependent weights and that can be used for the purposes of height reconstruction. To smooth the reconstructed surface, we fit quadrics to the height data for each patch. The smoothed surface normal directions are updated ensuring compliance with Lambert's law. The processes of height recovery and surface normal adjustment are interleaved and iterated until a stable surface is obtained. We provide results on synthetic and real-world imagery

The Elasticity of Substitution in Demand for Non-Tradable Goods in Costa Rica

Using quarterly (annual) information on consumption and prices of non-tradable goods for the period 1980-2002 (1981-2001), this paper estimates the elasticity of substitution in demand for non-tradable goods in Costa Rica. The unit root and cointegration properties of the time series are tested, and then controlling for exogenous variables, the elasticity of substitution belonging to the interval [1. 46, 2. 14] ([ 0. 22, 0. 28]) is estimated. These results are statistically robust.

Gobierno Corporativo en Costa Rica

(Disponible en idioma inglés únicamente) En este trabajo se analizan las prácticas de conducción empresarial en Costa Rica. En primer lugar, se calculan las medidas de conducción empresarial constitutivas empleando datos específicos de 87 compañías costarricenses, y se analizan sus efectos en su desempeño; aquí, la media de la conducción empresarial constitutiva de compañías cotizadas en bolsa es igual a 56. 14. En segundo lugar, se presentan nuevos elementos de juicio sobre las medidas constitutivas de la conducción empresarial de jure y de facto al nivel de compañía y sobre sus repercusiones en el desempeño de las mismas. Los resultados indican que la conducción empresarial de facto es mejor que la conducción empresarial de jure. Estos resultados sugieren que las compañías deben aplicar un conjunto de medidas adicionales para compensar la debilidad del entorno jurídico. Además, se presentan indicios de que una mejor gestión de conducción empresarial y medidas constitutivas se vinculan con un desempeño superior de la empresa. En tercer lugar, en este trabajo se analizan los factores que controlan en última instancia a las empresas cotizadas y no cotizadas en bolsa, y se establecen vínculos entre ellas y sus políticas de dividendos. Las empresas familiares son corrientes en Costa Rica y no necesariamente se vinculan con un mejor desempeño empresarial. En cuarto lugar, se estudia la evolución de la propiedad de compañías en Costa Rica. Por último se analizan cambios del Código de Comercio desde el punto de vista de la buena conducción empresarial.

Screening for childhood adversity: the what and when of identifying individuals at risk for lifespan health disparities.

Existing research on childhood adversity and health risk across the lifespan lacks specificity regarding which types of exposures to assess and when. The purpose of this study was to contribute to an empirically-supported framework to guide practitioners interested in identifying youth who may be at greatest risk for a lifelong trajectory of health disparities. We also sought to identify the point in childhood at which screening for adversity exposure would capture the largest group of at risk individuals for triage to prevention and intervention services. Participants (n = 4036) collected as part of the Midlife in the United States study reported their medical status and history including physical (cardiovascular disease, hypertension, obesity, diabetes, cancer) and mental health (depression, substance use problems, sleep problems). Participants indicated whether they were exposed to 7 adversities at any point in childhood and their age of exposure to 19 additional lifetime adversities before the age of 18. Parent drug abuse, dropping out or failing out of school, being fired from a job, and sexual assault during childhood exhibited the largest effect sizes on health in adulthood, which were comparable to the effects of childhood maltreatment. Childhood adversity screening in early adolescence may identify the largest proportion of youth at risk for negative health trajectories. The results of this descriptive analysis provide an empirical framework to guide screening for childhood adversity in pediatric populations. We discuss the implications of these observations in the context of prevention science and practice

El Desistimiento Y El Allanamiento En la Jurisprudencio De La Corte Interamericana De Derechos Humanos

Al analizar la jurisprudencia contenciosa de la Corte Interamericana de Derechos Humanos ( la Corte o la Corte Interamericana ), cabe destacar el hecho de que, durante sus primeros diecisiete afios de labores, 6sta se haya pronunciado sobre el fondo de nueve casos sometidos a su consideraci6n,\u27 en tres de lo cuales los Estados demandados se han allanado a las demandas formuladas por la Comisi6n Interamericana de Derechos Humanos ( Comisi6n o Comisi6n Interamnericana ) en las respectivas demandas

Dissolution experiments of commercial PWR (52 MWd/kgU) and BWR (53 MWd/kgU) spent nuclear fuel cladded segments in bicarbonate water under oxidizing conditions. Experimental determination of matrix and instant release fraction

The denominated instant release fraction (IRF) is considered in performance assessment (PA) exercises to govern the dose that could arise from the repository. A conservative definition of IRF comprises the total inventory of radionuclides located in the gap, fractures, and the grain boundaries and, if present, in the high burn-up structure (HBS). The values calculated from this theoretical approach correspond to an upper limit that likely does not correspond to what it will be expected to be instantaneously released in the real system. Trying to ascertain this IRF from an experimental point of view, static leaching experiments have been carried out with two commercial UO2 spent nuclear fuels (SNF): one from a pressurized water reactor (PWR), labelled PWR, with an average burn-up (BU) of 52 MWd/kgU and fission gas release (FGR) of 23.1%, and one from a boiling water reactor (BWR), labelled BWR, with an average BU of and 53 MWd/kgU and FGR of 3.9%.; One sample of each SNF, consisting of fuel and cladding, has been leached in bicarbonate water during one year under oxidizing conditions at room temperature (25 +/- 5) degrees C. The behaviour of the concentration measured in solution can be divided in two according to the release rate. All radionuclides presented an initial release rate that after some days levels down to a slower second one, which remains constant until the end of the experiment. Cumulative fraction of inventory in aqueous phase (FIAPc) values has been calculated. Results show faster release in the case of the PWR SNF. In both cases Np, Pu, Am, Cm, Y, Tc, La and Nd dissolve congruently with U, while dissolution of Zr, Ru and Rh is slower. Rb, Sr, Cs and Mo, dissolve faster than U. The IRF of Cs at 10 and 200 days has been calculated, being (3.10 +/- 0.62) and (3.66 +/- 0.73) for PWR fuel, and (035 +/- 0.07) and (0.51 +/- 0.10) for BWR fuel. (C) 2015 Elsevier B.V. All rights reserved.Peer ReviewedPostprint (author's final draft