Deformation and tidal evolution of close-in planets and satellites using a Maxwell viscoelastic rheology

In this paper we present a new approach to tidal theory. Assuming a Maxwell viscoelastic rheology, we compute the instantaneous deformation of celestial bodies using a differential equation for the gravity field coefficients. This method allows large eccentricities and it is not limited to quasi-periodic perturbations. It can take into account an extended class of perturbations, including chaotic motions and transient events. We apply our model to some already detected eccentric hot Jupiters and super-Earths in planar configurations. We show that when the relaxation time of the deformation is larger than the orbital period, spin-orbit equilibria arise naturally at half-integers of the mean motion, even for gaseous planets. In the case of super-Earths, these equilibria can be maintained for very low values of eccentricity. Our method can also be used to study planets with complex internal structures and other rheologies.Comment: 16 pages, 13 figures, 2 table

PICAE – Intelligent publication of audiovisual and editorial contents

The development in internet infrastructure and technology in last tow decades have given users and retailers the possibility to purchase and sell items online. This has of course broadened the horizons of what products can be offered outside of the traditional trading sense, to the point where virtually any product can be offered. These massive online markets have had a considerable impact on the habits of consumers, providing them access to a greater variety of products and information on these goods. This variety has made online commerce into a multi-billion dollar industry but it has also put the customer in a position where it is getting increasingly difficult to select the products that best fit their individual needs. In the same vein, the rise of both availability and the amounts of data that computers have been able to process in the last decades have allowed for many solutions that are computationally expensive to exist, and recommender systems are no exception. These systems are the perfect tools to overcome the information overload problem since they provide automated and personalized suggestions to consumers. The PICAE project tackles the recommendation problem in the audiovisual sector. The vast amount of audiovisual content that is available nowadays to the user can be overwhelming, which is why recommenders have been increasingly growing in popularity in this sector ---Netflix being the biggest example. PICAE seeks to provide insightful and personalized recommendations to users in a public TV setting. The PICAE project develops new models and analytical tools for recommending audiovisual and editorial content with the aim of improving the user experience, based on their profile and environment, and the level of satisfaction and loyalty. These new tools represent a qualitative improvement in the state of the art of television and editorial content recommendation. On the other hand, the project also improves the digital consumption index of these contents based on the identification of products that these new forms of consumption demand and how they must be produced, distributed and promoted to respond to the needs of this emerging market. The main challenge of the PICAE project is to resolve two differentiating aspects with respect to other existing solutions such as: variety and dynamic contents that requires a real-time analysis of the recommendation and the lack of available information about the user, who in these areas is reluctant to register, making it difficult to identify in multi-device consumption. This document will explain the contributions made in the development of the project, which can be divided in two: the development of the project, which can be divided in two: the development of a recommender system that takes into account information of both users and items and a deep analysis of the current metrics used to assess the performance of a recommender system

Adaptación internacional del método racional hidrológico: Estudio de las inundaciones en la Região do Norte de Portugal

Floods have a big capacity of create great social and economic losses in a short time interval. Spain and other countries have this problem in their territories. These can have different origins, being the rivers overflowing the more common cause. There are different approaches of these phenomena studies, and the modified Témez rational method is the referenced one in Spain, which with the GIS and hydrological simulation programs can create the flooding areas cartography, key information in the floods hazard management. But, is this method only valid for Spain, or is it applicable to other countries? The answer is that its adaptation to other countries is possible, always that the relevant modifications are made.In the Iberian Peninsula, Portugal is a country that has the flooding problem too. Because this country has a similar geological and geographical conditions to the western Spain, and the floods effects are similar in the Portuguese territories, the adaptation to this country it´s relatively simple.The aim of this work is the study of floods dynamics in Portugal, adapting the modified Témez rational method. This method will be applied in the Âncora river, in North Portugal region fluvial system because the geological and geographical conditions are similar to the west of Spain ones.Las inundaciones tienen una gran capacidad de crear grandes pérdidas sociales y económicas en un corto intervalo de tiempo. España y otros países tienen este problema en sus territorios. Estos pueden tener diferentes orígenes, siendo los ríos que desbordan la causa más común. Existen diferentes enfoques de estudio de estos fenómenos, y el método racional modificado de Témez es el referenciado en España, que con el SIG y los programas de simulación hidrológica puede crear la cartografía de las áreas inundables, información clave en la gestión del riesgo de inundaciones. Pero, ¿este método sólo es válido para España, o es aplicable a otros países? La respuesta es que su adaptación a otros países es posible, siempre que se realicen las modificaciones pertinentes.En la Península Ibérica, Portugal es un país que también tiene el problema de las inundaciones. Debido a que este país tiene unas condiciones geológicas y geográficas similares a las del oeste de España, y los efectos de las inundaciones son similares en los territorios portugueses, la adaptación a este país es relativamente sencilla.El objetivo de este trabajo es el estudio de la dinámica de las inundaciones en Portugal, adaptando el método racional modificado de Témez. Este método se aplicará en el río Âncora, en el sistema fluvial del norte de Portugal, ya que las condiciones geológicas y geográficas son similares a las del oeste de España

Biological and Clinical Aspects on the Treatment of Schizophrenia and Related Disorders : New Challenges

For several decades, it has been postulated that dopaminergic pathways explain the neurobiology of schizophrenia, the biological underpinnings of treatment responses and the main mechanisms of action of antipsychotics [...

Explainability in Deep Reinforcement Learning

A large set of the explainable Artificial Intelligence (XAI) literature is emerging on feature relevance techniques to explain a deep neural network (DNN) output or explaining models that ingest image source data. However, assessing how XAI techniques can help understand models beyond classification tasks, e.g. for reinforcement learning (RL), has not been extensively studied. We review recent works in the direction to attain Explainable Reinforcement Learning (XRL), a relatively new subfield of Explainable Artificial Intelligence, intended to be used in general public applications, with diverse audiences, requiring ethical, responsible and trustable algorithms. In critical situations where it is essential to justify and explain the agent's behaviour, better explainability and interpretability of RL models could help gain scientific insight on the inner workings of what is still considered a black box. We evaluate mainly studies directly linking explainability to RL, and split these into two categories according to the way the explanations are generated: transparent algorithms and post-hoc explainaility. We also review the most prominent XAI works from the lenses of how they could potentially enlighten the further deployment of the latest advances in RL, in the demanding present and future of everyday problems.Comment: Article accepted at Knowledge-Based System

New results and applications for multi-secret sharing schemes

In a multi-secret sharing scheme (MSSS), different secrets are distributed among the players in some set , each one according to an access structure. The trivial solution to this problem is to run independent instances of a standard secret sharing scheme, one for each secret. In this solution, the length of the secret share to be stored by each player grows linearly with (when keeping all other parameters fixed). Multi-secret sharing schemes have been studied by the cryptographic community mostly from a theoretical perspective: different models and definitions have been proposed, for both unconditional (information-theoretic) and computational security. In the case of unconditional security, there are two different definitions. It has been proved that, for some particular cases of access structures that include the threshold case, a MSSS with the strongest level of unconditional security must have shares with length linear in . Therefore, the optimal solution in this case is equivalent to the trivial one. In this work we prove that, even for a more relaxed notion of unconditional security, and for some kinds of access structures (in particular, threshold ones), we have the same efficiency problem: the length of each secret share must grow linearly with . Since we want more efficient solutions, we move to the scenario of MSSSs with computational security. We propose a new MSSS, where each secret share has constant length (just one element), and we formally prove its computational security in the random oracle model. To the best of our knowledge, this is the first formal analysis on the computational security of a MSSS. We show the utility of the new MSSS by using it as a key ingredient in the design of two schemes for two new functionalities: multi-policy signatures and multi-policy decryption. We prove the security of these two new multi-policy cryptosystems in a formal security model. The two new primitives provide similar functionalities as attribute-based cryptosystems, with some advantages and some drawbacks that we discuss at the end of this work.Peer ReviewedPostprint (author’s final draft

Awareness of illness and suicidal behavior in delusional disorder patients

Background The relationship between insight and suicidal behavior among psychotic patients is poorly studied and possibly mediated by clinical variables. Objectives Our goal was to investigate clinical differences in suicidal and non-suicidal delusional disorder (DD) patients, and to evaluate the relationship between insight, psychotic and depressive symptoms. Methods Cross-sectional study in 64 consecutive DD patients. For assessment, we used the Positive and Negative Syndrome Scale (PANSS), the Hamilton Rating Scale for Depression (HRSD-17), the Columbia Suicide Severity Rating Scale (C-SSRS), the Personal and Social Performance Scale (PSP), and the first three items of the SUMD scale for insight. The sample was divided according to the presence of suicide attempts. To investigate psychopathological associations, bivariate correlation coefficients were used. Age at onset served as covariate in subsequent analyses. Results Suicidal DD patients had higher depressive symptoms and were more frequently admitted than non-suicidal patients. A logistic regression model confirmed that insight, depressive symptoms and age at onset were predictors of suicidal behavior. Unawareness of the effects of medication was negatively related to depressive symptoms. After adjustment, depressive symptoms were weakly correlated to better insight into the effects of medication. No other statistically significant correlations were found. Discussion Depressive symptoms, insight and age at onset of disease may be potential predictors of suicidal behavior in DD patients