A posteriori error analysis of an augmented mixed finite element method for Darcy flow

We develop an a posteriori error analysis of residual type of a stabilized mixed finite element method for Darcy flow. The stabilized formulation is obtained by adding to the standard dual-mixed approach suitable residual type terms arising from Darcy's law and the mass conservation equation. We derive sufficient conditions on the stabilization parameters that guarantee that the augmented variational formulation and the corresponding Galerkin scheme are well-posed. Then, we obtain a simple a posteriori error estimator and prove that it is reliable and locally efficient. Finally, we provide several numerical experiments that illustrate the theoretical results and support the use of the corresponding adaptive algorithm in practice

Pairwise dichotomous cohesiveness measures

Producción CientíficaAbstract In a framework where experts or agents express their opinions in a dichotomous way, we analyze the cohesiveness of their opinions on axed set of issues in a population. A parametric family of related measures are introduced and axiomatically characterized. They are ordinally equivalent when the population isxed, and some further properties are proved. In order to argue that this restricted dichotomous situation is nevertheless versatile, the paper ends with several empirical illustrations based on real forecasts (for the 2012 American presidential election) and elections (with real data from referenda in two countries and from elections in several scientic societies).Ministerio de Economía, Industria y Competitividad (Project ECO2012-31933)Ministerio de Economía, Industria y Competitividad (Project ECO2012-32178)Ministerio de Economía, Industria y Competitividad (Proyect CGL2008-06003-C03-03/CLI)Ministerio de Economía, Industria y Competitividad (Project CGL2011-29396-C03-02)

Discretization of the Region of Interest

[EN]The meccano method was recently introduced to construct simultaneously tetrahedral meshes and volumetric parameterizations of solids. The method requires the information of the solid geometry that is defined by its surface, a meccano, i.e., an outline of the solid defined by connected polyhedral pieces, and a tolerance that fixes the desired approximation of the solid surface. The method builds an adaptive tetrahedral mesh of the solid (physical domain) as a deformation of an appropriate tetrahedral mesh of the meccano (parametric domain). The main stages of the procedure involve an admissible mapping between the meccano and the solid boundaries, the nested Kossaczký’s refinement, and our simultaneous untangling and smoothing algorithm. In this chapter, we focus on the application of the method to build tetrahedral meshes over complex terrain, that is interesting for simulation of environmental processes. A digital elevation map of the terrain, the height of the domain, and the required orography approximation are given as input data. In addition, the geometry of buildings or stacks can be considered. In these applications, we have considered a simple cuboid as meccano.Ministerio de Economía y Competitividad, Gobierno de España; Fondos FEDER; Departamento de Educación, Junta de Castilla y León; CONACYT-SENER, Fondo Sectorial CONACYT SENER HIDROCARBUROS

Integrative multi-omics analysis identifies a prognostic miRNA signature and a targetable miR-21-3p/TSC2/ mTOR axis in metastatic pheochromocytoma/ paraganglioma

Rationale: Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumors that present variable outcomes. To date, no effective therapies or reliable prognostic markers are available for patients who develop metastatic PPGL (mPPGL). Our aim was to discover robust prognostic markers validated through in vitro models, and define specific therapeutic options according to tumor genomic features. Methods: We analyzed three PPGL miRNome datasets (n=443), validated candidate markers and assessed them in serum samples (n=36) to find a metastatic miRNA signature. An integrative study of miRNome, transcriptome and proteome was performed to find miRNA targets, which were further characterized in vitro. Results: A signature of six miRNAs (miR-21-3p, miR-183-5p, miR-182-5p, miR-96-5p, miR-551b-3p, and miR-202-5p) was associated with metastatic risk and time to progression. A higher expression of five of these miRNAs was also detected in PPGL patients’ liquid biopsies compared with controls. The combined expression of miR-21-3p/miR-183-5p showed the best power to predict metastasis (AUC=0.804, P=4.67·10-18), and was found associated in vitro with pro-metastatic features, such as neuroendocrine-mesenchymal transition phenotype, and increased cell migration rate. A pan-cancer multi-omic integrative study correlated miR-21-3p levels with TSC2 expression, mTOR pathway activation, and a predictive signature for mTOR inhibitor-sensitivity in PPGLs and other cancers. Likewise, we demonstrated in vitro a TSC2 repression and an enhanced rapamycin sensitivity upon miR-21-3p expression. Conclusions: Our findings support the assessment of miR-21-3p/miR-183-5p, in tumors and liquid biopsies, as biomarkers for risk stratification to improve the PPGL patients’ management. We propose miR-21-3p to select mPPGL patients who may benefit from mTOR inhibitors

El lenguaje formal y las demostraciones en Matematicas para la Facultad de Economa y Empresa

Esta comunicación presenta un Proyecto de Innovación y Mejora Docente de la Uni- versidad de Salamanca que pretende paliar ciertas carencias detectadas en estudios previos, entre las que destacan el desconocimiento del lenguaje matemático (notación, formulación) y el défi cit de habilidades o técnicas para la resolución creativa de problemas (demostraciones). En este proyecto se pretende introducir a los alumnos de las Facultades de Economía y Empresa en el lenguaje formal matemático, presentar las principales técnicas de demostración y desarrollar la actividad creativa del estudiante. Los alumnos de nuestras titulaciones desconocen la notación y estructuras formales en matemáticas, lo que lastra de forma dramática su proceso de aprendizaje en asignaturas como Álgebra o Análisis Matemático y se extiende después a otras materias del Grado. La demostración es un proceso creativo que en general supone una gran di cultad para el estudiante. Este tipo de razonamientos no solo son útiles en materias relacionadas con las matemáticas, sino que están presentes en la resolución de cualquier problema entendido en sentido amplio. Conocer en profundidad las principales técnicas empleadas en los razonamientos matemáticos es fundamental para entender los contendidos de las materias instrumentales del primer curso de Grado y poder derivar después resultados de forma autónoma.In this paper we present the main topics included in a Teaching Project of the Uni- versity of Salamanca. The project intends to overcome certain de ciencies detected in previous studies, such as the lack of mathematical language (notation, formulation) and the de cit of skills or techniques for mathematical proofs. This project aims to introduce the students of the Faculties of Economics and Business in the formal mathematical language and to present the main techniques used in mathematical proofs since most of them do not know the notation and formal language in Mathematics. This feature affects their learning ability in Mathematical topics such as Algebra or Mathematical Analysis and many other subjects in their degrees. The mathematical proof is a creative process that may constitute a particular challenge for our students. Being able to understand the main techniques used in mathematical proofs is useful not only in Mathematical subjects but it is also important in the resolution of many problems in a broad sense

Valoracion de un Curso Cero de Matemáticas para una Facultad de Economía y Empresa

Last year the authors have developed a Pre-Core Mathematics on-line course for first year students at the Faculty of Economics and Business at the University of Salamanca (CASC ´ON et al. (2017a, 2007b)). In the present study, our goal is to evaluate this material and detect how we can improve it in the immediate future. Specifically, we present the results of a detailed study to assess its adaptation to our students, its quality and its weaknesses. It is our purpose to correct any deficiency and to achieve a really useful course for them, which is our primary aim. We have conducted a survey about the material among some of our colleagues at Secondary and High Schools, and another one, slightly different, among the first year students at the Faculty of Economic and Business (University of Salamanca). Their answers have been quite positive for us in both cases and they have also made us very valuable suggestions to improve the course. In addition, we present a consistency analysis that reveals that students who have used our material obtain higher grades.Tras la elaboración el curso pasado de diversos materiales para la implementación de un Curso Cero de Matemáticas para la Facultad de Economía y Empresa de la Universidad de Salamanca (CASCÓN y otros (2017a, 2017b)), es propósito del presente trabajo valorar dicho material con el fin de introducir las correspondientes mejoras en un futuro inmediato. Presentamos concretamente los resultados de un estudio pormenorizado para evaluar la adecuación, calidad y carencias de los materiales desarrollados, con el propósito de corregir las posibles deficiencias y conseguir así un material realmente útil para los estudiantes. Hemos elaborado sendos cuestionarios, uno enviado a nuestros compañeros profesores de Matemáticas en Enseñanza Secundaria y Bachillerato, y otro enviado a los estudiantes matriculados en la asignatura de Análisis Matemático del Grado en Administración y Dirección de Empresas de la Facultad de Economía y Empresa de la Universidad de Sala-manca. Presentamos los resultados obtenidos, bastante positivos, a nuestro parecer, así como sus sugerencias, que consideramos muy interesantes para mejorar algunos aspectos del curso. Además, se incluye un análisis de contingencia que revela que los alumnos que han utilizado los materiales obtienen una mejor calificación en la asignatura de Álgebra

Nuevos materiales didacticos virtuales para un Curso Cero de Matematicas en las titulaciones de Economa y Empresa

The problem of declining in basic mathematical skills and in the level of mathematical preparation of students entering higher education is widely recognized. In order to enhance student achievement, the authors have developed a Pre-Core Mathematics online course for rst year students at the Faculty of Economics and Business. Its primary aim is to provide students with basic mathematical knowledge to improve their technical skills as part of their university degree. The format is exible to enable students to work at their own pace. The contents are organised into four sections: theoretical basis, interactive activities designed to help students learn, applications to economic problems, and evaluation tests with feedback on their performance. We have used free and open source software (eXeLearning and LATEX/Beamer) as well as commercial software (Mathematica). The interactive material may be added to a course in Moodle.En este trabajo se describe y analiza un material on line creado por los autores y dirigido a los alumnos del primer curso de las titulaciones de Economa y Empresa. Su principal objetivo es el desarrollo de una herramienta que permita a los estudiantes adquirir una base solida en Matematicas, para afrontar con garantas de exito el grado por el que haya optado, es decir, mejorar su rendimiento academico. Los contenidos estan divididos en cuatro grandes bloques (aspectos teoricos, actividades, aplicaciones a la Economa y la empresa, y evaluacion) y su presentacion explota las ventajas de la enseñanza virtual: exibilidad, accesibilidad, trabajo autonomo, pensamiento crtico, retroalimentacion, etc. El material ha sido implementado combinando los softwares libres: eXeLearning y LATEX/Beamer y el software comercial Mathematica, y puede ser integrado en plataformas de entorno Moodle