Random resampling numerical simulations applied to a SEIR compartmental model

In this paper, we apply resampling techniques to a modified compartmental SEIR model which takes into account the existence of undetected infected people in an epidemic. In particular, we implement numerical simulations for the evolution of the first wave of the COVID-19 pandemic in Spain in 2020. We show, by using suitable measures of goodness, that the point estimates obtained by the bootstrap samples improve the ones of the original data. For example, the relative error of detected currently infected people is equal to 0.061 for the initial estimates, while it is reduced to 0.0538 for the mean over all bootstrap estimated series

Introducing migratory flows in life table construction

The purpose of life tables is to describe the mortality behav iour of particular groups. The construction of general life tables is based on death statis tics and census figures of resident populations under the hypothesis of closed demographic sys tem. Among other assumptions, this hypothesis implicitly assumes that entries (immigrants) a nd exits (emigrants) of the population are usually not significant (being almost of the same magnitu de for each age compensating each other). This paper theoretically extends the classical sol ution to open demographic systems and studies the impact of this hypothesis in constructing a life table. In particular, using the data of residential variations made available to the public by the S panish National Statistical Office (INE, Instituto Nacional de Estad ́ ıstica) to approximate migratory flows, we introduce in the p rocess of constructing a life table these flows and compare, before and after graduation, the crude mortality rates and the adjusted death probabilities obtained when mi gratory flows are, and are not, taken into accountPeer Reviewe

New coronavirus outbreak. Lessons learned from the severe acute respiratory syndrome epidemic

System dynamics approach offers great potential for addressing how intervention policies can affect the spread of emerging infectious diseases in complex and highly networked systems. Here, we develop a model that explains the severe acute respiratory syndrome coronavirus (SARS-CoV) epidemic that occurred in Hong Kong in 2003. The dynamic model developed with system dynamics methodology included 23 variables (five states, four flows, eight auxiliary variables, six parameters), five differential equations and 12 algebraic equations. The parameters were optimized following an iterative process of simulation to fit the real data from the epidemics. Univariate and multivariate sensitivity analyses were performed to determine the reliability of the model. In addition, we discuss how further testing using this model can inform community interventions to reduce the risk in current and future outbreaks, such as the recently Middle East respiratory syndrome coronavirus (MERS-CoV) epidemic.Centro de Biología Molecular ‘Severo Ochoa’ by the Fundación Ramón ArecesPeer Reviewe

Desacuerdo español e inglés: un análisis de variación cultural y situacional

This paper highlights the results of an intercultural study within the theoretical frame of (im)politeness about the way in which Spanish and English speakers manage situations of disagreement. However, in order not to ignore the internal variation that in each culture exists, cultural contrasts are analysed while simultaneously taking into account situational variation. This study is based upon a questionnaire carried out among 240 informants. Using open questions, both qualitative and quantitative methodology is employed. As regards (im)politeness, the rapport management theory by Spencer-Oatey (2002, 2008) is the model employed for reference. The replies of the informants are analysed regarding their possible reaction to a situation of disagreement in different contextual frames. It is observed whether the speaker does or does not express disagreement, as well as the way it is expressed (mitigated, open or boosted) and the kind of strategies that are employed.Este trabajo ofrece los resultados de un estudio intercultural, desde el marco teórico de la (des)cortesía, acerca del modo en que hablantes españoles e ingleses gestionan situaciones de desacuerdo. Además, con el objetivo de no pasar por alto la variación interna existente dentro de cada cultura, el contraste cultural es analizado a la vez que se da cuenta de la variación situacional. El estudio está basado en un cuestionario distribuido a 240 informantes. Sobre la base de preguntas abiertas, se utiliza metodología tanto cualitativa como cuantitativa. En relación con la (des)cortesía, el modelo teórico de referencia es el de gestión interrelacional (rapport management) de Spencer-Oatey (2002, 2008). Las respuestas de los informantes son analizadas en relación con su posible reacción a una situación de desacuerdo en diferentes contextos situacionales. Se observa si el hablante expresa o no desacuerdo, así como el modo en que este es expresado (mitigado, abierto o potenciado) y el tipo de estrategias empleadas para hacerlo

Corporate board and default risk of financial firms

This paper analyses the impact of corporate board structure on default risk of European banking firms. We focus on four core aspects of boards that have been addressed in Directive 2013/36/ EU to strengthen the corporate governance of banks: the size of boards, their independence, the participation of female directors and CEO duality. We employ panel data analysis to study the 109 European listed banks between 2002 and 2019. Default risk is estimated by Merton’s (1974) distance to default. We take into account the presence of unobservable heterogeneity, simultaneity and dynamic endogeneity and estimate the model using the dynamic difference and dynamic system GMM methodologies. The results show that the size of the board influences banks’ default risk. Furthermore, bank size, firm profitability and GDP also exert a considerable influence

Robótica asistencial en lengua de signos

El objetivo de este Trabajo Final de Máster es la interpretación de sentencias de la Lengua de Signos Española relativas a tareas diarias mediante técnicas de deep learning con el fin de implementar un intérprete automático. Para el seguimiento de los brazos y manos involucrados en el signado de los diferentes gestos se emplea Openpose, un sistema de detección de cuerpo, cara, pies y manos en tiempo real. Usando una cámara Azure Kinect como herramienta para la captura de imágenes. Los resultados obtenidos por Openpose son introducidos en una Red Neuronal Artificial donde se produce el reconocimiento. En este trabajo se han estudiado, analizado y comparado distintas arquitecturas con el fin de encontrar la más adecuada para un correcto reconocimiento de signos. Adicionalmente se abarca la creación de un dataset de las diversas palabras de la Lengua de Signos Española necesarias para la creación de dichas frases. Empleando para ello la cámara Azure Kinect y la herramienta Openpose para la extracción de los puntos necesarios en manos y brazos

Seasonality in Tourism: Do Senior Programs Mitigate It?

Seasonality is a widely recognised and accredited phenomenon known to cause an imbalance in tourism activity throughout the year, prompting tourist destinations, both public and private, to consider how best to plan the use of their resources. One way of mitigating the economic imbalances that seasonality can cause is to find strategies for seasonal adjustment, such as travel programmes aimed at the elderly. This paper analyses the seasonality of tourism activity in some EU countries, and in particular in Spain. Different indicators are used to compare the results and carry out a sensitivity analysis. The study then focuses on tourism programmes for the elderly in Spain to see whether this type of programme helps to alleviate the seasonality of tourism activity. To corroborate this, an econometric model is specified and estimated, which enables the scope of these programmes to be compared

Introducing migratory flows in life table construction

The purpose of life tables is to describe the mortality behaviour of particular groups. The construction of general life tables is based on death statistics and census figures of resident populations under the hypothesis of closed demographic system. Among other assumptions, this hypothesis implicitly assumes that entries (immigrants) and exits (emigrants) of the population are usually not significant (being almost of the same magnitude for each age compensating each other). This paper theoretically extends the classical solution to open demographic systems and studies the impact of this hypothesis in constructing a life table. In particular, using the data of residential variations made available to the public by the Spanish National Statistical Office (INE, Instituto Nacional de Estadística) to approximate migratory flows, we introduce in the process of constructing a life table these flows and compare, before and after graduation, the crude mortality rates and the adjusted death probabilities obtained when migratory flows are, and are not, taken into account

On Differential Equations with Delay in Banach Spaces and Attractors for Retarded Lattice Dynamical Systems

In this paper we first prove a rather general theorem about existence of solutions for an abstract differential equation in a Banach space by assuming that the nonlinear term is in some sense weakly continuous. We then apply this result to a lattice dynamical system with delay, proving also the existence of a global compact attractor for such system

Asymptotic Behaviour of a Logistic Lattice System

In this paper we study the asymptotic behaviour of solutions of a lattice dynamical system of a logistic type. Namely, we study a system of in nite ordinary di erential equations which can be obtained after the spatial discretization of a logistic equation with di usion. We prove that a global attractor exists in suitable weighted spaces of sequences