La persona adecuada en el momento adecuado: los miembros del comité de auditoría y la calidad de la información financiera

We analyze some personal characteristics of the members of the audit committee of the Spanish listed firms and the relation between these characteristics and earnings management. We find a non-linear relation with tenure, so that long tenures can initially compromise the directors’ independence but, after a given threshold, longer tenures improve the expertise of the members. Serving in too many boards has a negative influence on the ability of directors to detect earnings management, and higher academic background and more diverse professional background improve the directors’ abilities.En el presente trabajo analizamos la relación entre algunas características personales de los miembros del comité de auditoría de las empresas cotizadas españolas y la gestión del resultado. Nuestros resultados muestran una relación no lineal con la antigüedad en el consejo: mientras que en los primeros estadios una mayor duración puede comprometer la independencia de los consejeros, llega un punto en el que la mayor antigüedad en el comité incrementa su experiencia. Formar parte de un número excesivo de consejos redunda en una menor capacidad de los consejeros para detectar la gestión del resultado. Una formación académica más elevada y una experiencia profesional más diversa contribuyen a mejorar la calidad de la información financiera

Development of an Analytic Nodal Diffusion Solver in Multigroups for 3D Reactor Cores with Rectangular or Hexagonal Assemblies.

More accurate modelling of physical phenomena involved in present and future nuclear reactors requires a multi-scale and multi-physics approach. This challenge can be accomplished by the coupling of best-estimate core-physics, thermal-hydraulics and multi-physics solvers. In order to make viable that coupling, the current trends in reactor simulations are along the development of a new generation of tools based on user-friendly, modular, easily linkable, faster and more accurate codes to be integrated in common platforms. These premises are in the origin of the NURESIM Integrated Project within the 6th European Framework Program, which is envisaged to provide the initial step towards a Common European Standard Software Platform for nuclear reactors simulations. In the frame of this project and to reach the above-mentioned goals, a 3-D multigroup nodal solver for neutron diffusion calculations called ANDES (Analytic Nodal Diffusion Equation Solver) has been developed and tested in-depth in this Thesis. ANDES solves the steady-state and time-dependent neutron diffusion equation in threedimensions and any number of energy groups, utilizing the Analytic Coarse-Mesh Finite-Difference (ACMFD) scheme to yield the nodal coupling equations. It can be applied to both Cartesian and triangular-Z geometries, so that simulations of LWR as well as VVER, HTR and fast reactors can be performed. The solver has been implemented in a fully encapsulated way, enabling it as a module to be readily integrated in other codes and platforms. In fact, it can be used either as a stand-alone nodal code or as a solver to accelerate the convergence of whole core pin-by-pin code systems. Verification of performance has shown that ANDES is a code with high order definition for whole core realistic nodal simulations. In this paper, the methodology developed and involved in ANDES is presented

Improving PWR core simulations by Monte Carlo uncertainty analysis and Bayesian inference

A Monte Carlo-based Bayesian inference model is applied to the prediction of reactor operation parameters of a PWR nuclear power plant. In this non-perturbative framework, high-dimensional covariance information describing the uncertainty of microscopic nuclear data is combined with measured reactor operation data in order to provide statistically sound, well founded uncertainty estimates of integral parameters, such as the boron letdown curve and the burnup-dependent reactor power distribution. The performance of this methodology is assessed in a blind test approach, where we use measurements of a given reactor cycle to improve the prediction of the subsequent cycle. As it turns out, the resulting improvement of the prediction quality is impressive. In particular, the prediction uncertainty of the boron letdown curve, which is of utmost importance for the planning of the reactor cycle length, can be reduced by one order of magnitude by including the boron concentration measurement information of the previous cycle in the analysis. Additionally, we present first results of non-perturbative nuclear-data updating and show that predictions obtained with the updated libraries are consistent with those induced by Bayesian inference applied directly to the integral observables.Comment: 10 pages, 11 figure

The origins of the choral movement in Spain

El germen del fenómeno social que supuso el movimiento coral en España lo encontramos a mediados del siglo XIX. Desde entonces, dicho fenómeno, ha experimentado no pocas e importantes transformaciones, pero se ha mantenido a lo largo del tiempo hasta nuestros días. En el presente artículo se realiza una semblanza de los orígenes del movimiento coral en Europa a través de diversos estudios desarrollados en torno a este tema para centrarnos, posteriormente, en los inicios del movimiento coral en España. También se analizarán las características más relevantes del coralismo en esta época y su posterior evolución.We can fnd the origin of the choral movement in Spain in the middle of the nineteenth century. Since then, this social phenomenon has experienced many changes making it what it is today. In this article, a description of the origin of the choral movement in Europa is given. To that end, many articles and documents were consulted. After that, the origin, the most relevant characteristics of the choral movement in Spain and the more relevant features of choralism at that time and its evolution will also be analysed

Análisis de la transmutación de Actínidos Minoritarios en un reactor rápido de sodio con modelo de carga homogéneo mediante el código MCNPX-CINDER

El reactor rápido refrigerado por sodio (SFR) constituye uno de los conceptos más prometedores de los seis considerados en la Generación IV de reactores nucleares, encontrándose actualmente en fase de investigación. En este marco surge el proyecto europeo CP ESFR (Collaborative Project for an European Sodium Fast Reactor) cuya finalidad es analizar los diversos desafíos y oportunidades que el desarrollo de este tipo de reactores plantea, ya sea en términos de seguridad, tecnología de sodio, capacidades transmutadoras, etc

On the Extension of the Analytic Nodal Diffusion Solver ANDES to Sodium Fast Reactors

Within the framework of the Collaborative Project for a European Sodium Fast Reactor, the reactor physics group at UPM is working on the extension of its in-house multi-scale advanced deterministic code COBAYA3 to Sodium Fast Reactors (SFR). COBAYA3 is a 3D multigroup neutron kinetics diffusion code that can be used either as a pin-by-pin code or as a stand-alone nodal code by using the analytic nodal diffusion solver ANDES. It is coupled with thermalhydraulics codes such as COBRA-TF and FLICA, allowing transient analysis of LWR at both fine-mesh and coarse-mesh scales. In order to enable also 3D pin-by-pin and nodal coupled NK-TH simulations of SFR, different developments are in progress. This paper presents the first steps towards the application of COBAYA3 to this type of reactors. ANDES solver, already extended to triangular-Z geometry, has been applied to fast reactor steady-state calculations. The required cross section libraries were generated with ERANOS code for several configurations. The limitations encountered in the application of the Analytic Coarse Mesh Finite Difference (ACMFD) method –implemented inside ANDES– to fast reactors are presented and the sensitivity of the method when using a high number of energy groups is studied. ANDES performance is assessed by comparison with the results provided by ERANOS, using a mini-core model in 33 energy groups. Furthermore, a benchmark from the NEA for a small 3D FBR in hexagonal-Z geometry and 4 energy groups is also employed to verify the behavior of the code with few energy groups

Applying Qualitative Research to Develop a Guide for Parents of Newborns With Hypoxic-Ischemic Encephalopathy

Moderate-to-severe hypoxic-ischemic encephalopathy (HIE) is a significant cause of neonatal mortality and permanent disability in surviving newborns. Therapeutic hypothermia (TH) is the only effective intervention to reduce these outcomes. Being a parent of these babies is a traumatic and strenuous event. To address these difficulties, parents need information and support. The aim of this article is to describe a qualitative methodological process followed to develop a guide for parents of a newborn with HIE receiving TH as an addendum to clinical practice guidelines. The guide based on the experience of parents of newborns with HIE is presented as 16 meaningful questions and a glossary. It provides information to parents about HIE, treatment and care, future outcomes, and coping strategies. The final version, in Spanish and English, has a didactic format with simple wording, parents’ verbatim queries, and illustrations made expressly for the guide. Furthermore, we think showing the methodological process we followed to develop the guide, detailing the difficulties that arose in doing so, and making the reflexivity of the researchers explicit may provide support for other teams undertaking similar projects. Likewise, this article illustrates in a practical way how the perspective of family can be incorporated into clinical practice guidelines.Parents’ guide was part of the Spanish National Health System Clinical Practice Guideline on perinatal hypoxic-ischemic encephalopathy. Funding was received for the development of it from the Institute of Health and the Health Quality and Assessment Agency of Catalonia. It has been funded by the Spanish Ministry of Health, Social Services, and Equality (PIC-108-13)

A proposed parameterization of interface discontinuity factors depending on neighborhood for pin-by-pin diffusion computations for LWR

There exists an interest in performing full core pin-by-pin computations for present nuclear reactors. In such type of problems the use of a transport approximation like the diffusion equation requires the introduction of correction parameters. Interface discontinuity factors can improve the diffusion solution to nearly reproduce a transport solution. Nevertheless, calculating accurate pin-by-pin IDF requires the knowledge of the heterogeneous neutron flux distribution, which depends on the boundary conditions of the pin-cell as well as the local variables along the nuclear reactor operation. As a consequence, it is impractical to compute them for each possible configuration. An alternative to generate accurate pin-by-pin interface discontinuity factors is to calculate reference values using zero-net-current boundary conditions and to synthesize afterwards their dependencies on the main neighborhood variables. In such way the factors can be accurately computed during fine-mesh diffusion calculations by correcting the reference values as a function of the actual environment of the pin-cell in the core. In this paper we propose a parameterization of the pin-by-pin interface discontinuity factors allowing the implementation of a cross sections library able to treat the neighborhood effect. First results are presented for typical PWR configurations