La reforma de la Ley de Extranjería

La reforma propuesta de la Ley de Extranjería tiene un alcance limitado lo que pone en duda su oportunidad en un momento de crisis económica

Europa ante la xenofobia y sus responsabilidades

Hace tiempo que Europa se viene desnudando de sus valores fundacionales, muchos de ellos desde hace tiempo por los suelos donde son pisoteados según las necesidades de los Estados. El Plan de Acción conjunto acordado entre los gobierno de la UE y Turquía en la madrugada del 8 de marzo es un ejemplo más del retroceso de Europa y su hundimiento en el fango de la xenofobia, el egoísmo, la insolidaridad y el nacionalismo identitario europeo. Pero ese fango no surge de la nada

Towards a Theory of the Credit-Risk Balance Sheet

This article designs what it calls a Credit-Risk Balance Sheet (the risk being that of default by customers), a tool which, in principle, can contribute to revealing, controlling and managing the bad debt risk arising from a companys commercial credit, whose amount can represent a significant proportion of both its current and total assets. To construct it, we start from the duality observed in any credit transaction of this nature, whose basic identity can be summed up as Credit = Risk. Credit is granted by a company to its customer, and can be ranked by quality (we suggest the credit scoring system) and risk can either be assumed (interiorised) by the company itself or transferred to third parties (exteriorised). What provides the approach that leads to us being able to talk with confidence of a real Credit-Risk Balance Sheet with its methodological robustness is that the dual vision of the credit transaction is not, as we demonstrate, merely a classificatory duality (a double risk-credit classification of reality) but rather a true causal relationship, that is, a risk-credit causal duality. Once said Credit-Risk Balance Sheet (which bears a certain structural similarity with the classic net asset balance sheet) has been built, and its methodological coherence demonstrated, its properties static and dynamic are studied. Analysis of the temporal evolution of the Credit-Risk Balance Sheet and of its applications will be the object of subsequent works.credit-risk balance sheet, bad debts, risk, insolvency, commercial credit, credit, credit information, business risk, credit risk, credit management

A Nonparametric Conjugate Prior Distribution for the Maximizing Argument of a Noisy Function

We propose a novel Bayesian approach to solve stochastic optimization problems that involve finding extrema of noisy, nonlinear functions. Previous work has focused on representing possible functions explicitly, which leads to a two-step procedure of first, doing inference over the function space and second, finding the extrema of these functions. Here we skip the representation step and directly model the distribution over extrema. To this end, we devise a non-parametric conjugate prior based on a kernel regressor. The resulting posterior distribution directly captures the uncertainty over the maximum of the unknown function. We illustrate the effectiveness of our model by optimizing a noisy, high-dimensional, non-convex objective function.Comment: 9 pages, 5 figure

Towards a Theory of the Credit-Risk Balance Sheet (II). The Evolution of its Structure

This article has an immediate predecessor, upon which it is based and with which readers must necessarily be familiar: Towards a Theory of the Credit-Risk Balance Sheet (Vallverdu, Somoza and Moya, 2006). The Balance Sheet is conceptualised on the basis of the duality of a credit-based transaction; it deals with its theoretical foundations, providing evidence of a causal credit-risk duality, that is, a true causal relationship; its characteristics, properties and its static and dynamic characteristics are analyzed. This article, which provides a logical continuation to the previous one, studies the evolution of the structure of the Credit-Risk Balance Sheet as a consequence of a businesss dynamics in the credit area. Given the Credit-Risk Balance Sheet of a company at any given time, it attempts to estimate, by means of sequential analysis, its structural evolution, showing its usefulness in the management and control of credit and risk. To do this, it bases itself, with the necessary adaptations, on the by-now classic works of Palomba and Cutolo. The establishment of the corresponding transformation matrices allows one to move from an initial balance sheet structure to a final, future one, to understand its credit-risk situation trends, as well as to make possible its monitoring and control, basic elements in providing support for risk management.credit-risk balance sheet, bad debts, risk, insolvency, commercial credit, transformation matrix, probabilities matrix, credit information, business risk, credit risk, credit management

Biofilm dynamics characterization using a novel DO-MEA sensor: mass transport and biokinetics

Biodegradation process modeling is an essential tool for the optimization of biotechnologies related to gaseous pollutant treatment. In these technologies, the predominant role of biofilm, particularly under conditions of no mass transfer limitations, results in a need to determine what processes are occurring within the same. By measuring the interior of the biofilms, an increased knowledge of mass transport and biodegradation processes may be attained. This information is useful in order to develop more reliable models that take biofilm heterogeneity into account. In this study, a new methodology, based on a novel dissolved oxygen (DO) and mass transport microelectronic array (MEA) sensor, is presented in order to characterize a biofilm. Utilizing the MEA sensor, designed to obtain DO and diffusivity profiles with a single measurement, it was possible to obtain distributions of oxygen diffusivity and biokinetic parameters along a biofilm grown in a flat plate bioreactor (FPB). The results obtained for oxygen diffusivity, estimated from oxygenation profiles and direct measurements, revealed that changes in its distribution were reduced when increasing the liquid flow rate. It was also possible to observe the effect of biofilm heterogeneity through biokinetic parameters, estimated using the DO profiles. Biokinetic parameters, including maximum specific growth rate, the Monod half-saturation coefficient of oxygen, and the maintenance coefficient for oxygen which showed a marked variation across the biofilm, suggest that a tool that considers the heterogeneity of biofilms is essential for the optimization of biotechnologies.Peer ReviewedPostprint (published version