ON P-ADIC FIELDS AND P-GROUPS

The dissertation is divided into two parts. The first part mainly treats a conjecture of Emil Artin from the 1930s. Namely, if f = a_1x_1^d + a_2x_2^d +...+ a_{d^2+1}x^d where the coefficients a_i lie in a finite unramified extension of a rational p-adic field, where p is an odd prime, then f is isotropic. We also deal with systems of quadratic forms over finite fields and study the isotropicity of the system relative to the number of variables. We also study a variant of the classical Davenport constant of finite abelian groups and relate it to the isotropicity of diagonal forms. The second part deals with the theory of finite groups. We treat computations of Chermak-Delgado lattices of p-groups. We compute the Chermak-Delgado lattices for all p-groups of order p^3 and p^4 and give results on p-groups of order p^5

Las políticas activas de empleo y el problema del paro de larga duración

Nuestro país ahora tiene cuatro millones de parados, de los cuales la mitad lo son de larga duración. Por ello éste sigue siendo el principal problema de nuestros ciudadanos, tal como lo refleja la última encuesta del CIS. En el trabajo se hace una revisión de las políticas activas de empleo aplicadas en España durante la última década. Destaca la excesiva dedicación presupuestaria a subvenciones a la contratación, en menoscabo de la formación para mejorar la empleabilidad. Y dentro de la formación una constante fue lo limitado de sus contenidos y la falta de actualización. En 2013 con la “Estrategia Española de Activación para el Empleo 2014-2016” se implanta un nuevo modelo orientado a la consecución de objetivos. Tiene tambien sus fallos como que no evalúa la eficiencia de los programas para conseguir insertar al parado en el mercado laboral. Solo compara el volumen de programas con el volumen de parados. Otro problema que concurre para conseguir un buen resultado, es la insuficiencia de los Servicios Públicos de Empleo para llevar a cabo lo que contempla el nuevo modelo. Cierto que se están dando pasos en la buena dirección, pero el reto para que funcione eficazmente es enorme

Las políticas activas de empleo y el problema del paro de larga duración

Nuestro país ahora tiene cuatro millones de parados, de los cuales la mitad lo son de larga duración. Por ello éste sigue siendo el principal problema de nuestros ciudadanos, tal como lo refleja la última encuesta del CIS. En el trabajo se hace una revisión de las políticas activas de empleo aplicadas en España durante la última década. Destaca la excesiva dedicación presupuestaria a subvenciones a la contratación, en menoscabo de la formación para mejorar la empleabilidad. Y dentro de la formación una constante fue lo limitado de sus contenidos y la falta de actualización. En 2013 con la “Estrategia Española de Activación para el Empleo 2014-2016” se implanta un nuevo modelo orientado a la consecución de objetivos. Tiene tambien sus fallos como que no evalúa la eficiencia de los programas para conseguir insertar al parado en el mercado laboral. Solo compara el volumen de programas con el volumen de parados. Otro problema que concurre para conseguir un buen resultado, es la insuficiencia de los Servicios Públicos de Empleo para llevar a cabo lo que contempla el nuevo modelo. Cierto que se están dando pasos en la buena dirección, pero el reto para que funcione eficazmente es enorme

Fully Stochastic Distributed Methodology for Multivariate Flood Frequency Analysis

An adequate estimation of the extreme behavior of basin response is essential both for designing river structures and for evaluating their risk. The aim of this paper is to develop a new methodology to generate extreme hydrograph series of thousands of years using an event-based model. To this end, a spatial-temporal synthetic rainfall generator (RainSimV3) is combined with a distributed physically-based rainfall?runoff event-based model (RIBS). The use of an event-based model allows simulating longer hydrograph series with less computational and data requirements but need to characterize the initial basis state, which depends on the initial basin moisture distribution. To overcome this problem, this paper proposed a probabilistic calibration simulation approach, which considers the initial state and the model parameters as random variables characterized by a probability distribution though a Monte Carlo simulation. This approach is compared with two other approaches, the deterministic and the semi-deterministic approaches. Both approaches use a unique initial state. The deterministic approach also uses a unique value of the model parameters while the semi-deterministic approach obtains these values from its probability distribution through a Monte Carlo simulation, considering the basin variability. This methodology has been applied to the Corbès and Générargues basins, in the Southeast of France. The results show that the probabilistic approach offers the best fit. That means that the proposed methodology can be successfully used to characterize the extreme behavior of the basin considering the basin variability and overcoming the basin initial state problem

Stochastic Approach to Hydrological Dam Safety in the Framework of the New Dam Safety Standards in Spain

The approval of the Technical Safety Standards for dams and reservoirs in Spain in 2021 increased the hydrological safety requirements, being necessary to check if measures have to be implemented in dams designed according to the prior standards. Some of these dams have scarce instrumentation and lack of hydrometeorological data. This work proposes a simple but sounded fully-stochastic methodology for assessing the hydrological safety of dams within this situation, potentially applicable outside academia. The methodology has been applied to a case study based on a real dam, and compared the results obtained to those of the standard deterministic procedure. We have found that the fully-stochastic methodology leads to higher maximum reservoir levels for the same return period, leading therefore to more conservative results for the case study. On this regard, potential flaws have been detected regarding the hypothesis of the standard deterministic procedure, discussed and solved by the proposed fully-stochastic methodology, which accounts for the stochastic nature of variables such as rainfall temporal patterns and antecedent runoff conditions. Moreover, the proposed methodology can be adapted for accounting for operational variables such as the initial reservoir level when the flood event occurs, providing results that resemble more to the reality of nature and the reality of dam-reservoir systems

Are circles isoperimetric in the plane with density er?

We prove that an isoperimetric region in R2 with density er must be convex and contain the origin, and provide numerical evidence that circles about the origin are isoperimetric, as predicted by the Log-Convex Density Conjecture

Gender and fiction: a window to history

S

Dependence Between Extreme Rainfall Events and the Seasonality and Bivariate Properties of Floods. A Continuous Distributed Physically-Based Approach

This paper focuses on proposing the minimum number of storms necessary to derive the extreme flood hydrographs accurately through event-based modelling. To do so, we analyzed the results obtained by coupling a continuous stochastic weather generator (the Advanced WEather GENerator) with a continuous distributed physically-based hydrological model (the TIN-based real-time integrated basin simulator), and by simulating 5000 years of hourly flow at the basin outlet. We modelled the outflows in a basin named Peacheater Creek located in Oklahoma, USA. Afterwards, we separated the independent rainfall events within the 5000 years of hourly weather forcing, and obtained the flood event associated to each storm from the continuous hourly flow. We ranked all the rainfall events within each year according to three criteria: Total depth, maximum intensity, and total duration. Finally, we compared the flood events obtained from the continuous simulation to those considering the N highest storm events per year according to the three criteria and by focusing on four different aspects: Magnitude and recurrence of the maximum annual peak-flow and volume, seasonality of floods, dependence among maximum peak-flows and volumes, and bivariate return periods. The main results are: (a) Considering the five largest total depth storms per year generates the maximum annual peak-flow and volume, with a probability of 94% and 99%, respectively and, for return periods higher than 50 years, the probability increases to 99% in both cases; (b) considering the five largest total depth storms per year the seasonality of flood is reproduced with an error of less than 4% and (c) bivariate properties between the peak-flow and volume are preserved, with an error on the estimation of the copula fitted of less than 2%.The authors acknowledge the computer resources and technical assistance provided by the Centro de Supercomputacion y Visualizacion de Madrid (CeSViMa) and the funds from Universidad Politecnica de Madrid in the framework of their Program "Ayudas para contratos predoctorales para la realizacion del doctorado en sus escuelas, facultad, centro e institutos de I + D + i", "ayudas a proyectos de I + D de investigadores posdoctorales" Ref. number: VJIDOCUPM19AFSW) and "XVI Convocatoria de ayudas del consejo social para el fomento de la formacion e internacionalizacion de doctorandos". The authors also wish to gratefully acknowledge Enrique Vivoni, Giuseppe Mascaro, Ara Ko, Adil Mounir, and their teammates for the data, advice, and support provided during the stay of A.S.W. and I.G.M. in Arizona State University. The authors also gratefully acknowledge Riccardo Nalesso for his help provided during the first steps of the experiment. This research received no external fundin