On p-Compact Sets in Classical Banach Spaces

Given p ≥ 1, we denote by Cp the class of all Banach spaces X satisfying the equality Kp(Y,X) = Πdp(Y,X) for every Banach space Y , Kp (respectively, Πdp ) being the operator ideal of p-compact operators (respectively, of operators with p-summing adjoint). If X belongs to Cp, a bounded set A ⊂ X is relatively p-compact if and only if the evaluation map U∗ A : X∗ −→ ∞(A) is p-summing. We obtain p-compactness criteria valid for Banach spaces in Cp

Combining linear and nonlinear diffusion

In this paper we study a generalized porous medium equation where the diffusion rate, say m(x) —spatially heterogeneous—, is assumed to be linear, m = 1, on a piece of the support domain, Ω1, and slow nonlinear, m(x) > 1, in its complement, Ωm := Ω \ Ω¯1. Most precisely, we characterize the existence of positive solutions and construct the corresponding global bifurcation diagram as one of the parameters of the model changes, showing that a continuous transition occurs between the diagrams of the completely linear case (Ω = Ω1) and of the completely nonlinear case (Ωm = Ω). As a result, the effect of a localized slow diffusion rate with varying support is completely characterized. Our analysis is imperative in order to design porous media multi-components systems with changing diffusion rates.Ministerio de Ciencia y Tecnologí

On the symbiotic Lotka–Volterra model with diffusion and transport effects

In this work we analyze the existence, stability and multiplicity of coexistence states for a symbiotic Lotka-Volterra model with general diffusivities and transport effects. Global bifurcation theory, blowing up arguments for a priori bounds, singular perturbation results, singularity theory and fixed point index in cones are among the techniques used to get our results and to explain the drastic change of behavior exhibited by the dynamics of the model between the cases of weak and strong mutualism between the species. Our methodology works out to treat much more general classes of symbiotic models.Dirección General de Investigación Científica y Técnica (Ministerio de Economía y Competitividad)Ministério da Ciencia, Tecnologia e Ensino Superior. Direcçao-Geral do Ensino Superior PB96-062

El consumo y el lenguaje del reguetón a debate entre los adolescentes

Music is not just a simple pastime, as it also contributes to the construction of identities, promotes cultural development or generates close affective ties between those who share the same musical preferences. In recent years, reggaeton has become very popular, a musical genre admired by youth and characterized by containing, in its lyrics, discriminatory messages towards women. In this sense, it is vitally important to question the impact exerted on adolescents, where it has penetrated with greater impetus, analyzing the possible consequences that it may have when building or reinforcing macho thoughts. A qualitative research is proposed that tries to examine the perceptions of adolescents. Through two focus groups, the opinions of young people enrolled in the educational stages of 2nd ESO and 3rd ESO from two secondary education institutes in the province of Huelva are debated and confronted. During the focus group sessions, the participants question the relationship between different variables that emerge from the properties of the language used in some reggaeton lyrics, such as machismo or gender violence. The analysis of the speeches derived from the work sessions has been developed through the Maxqda software. The results reveal a type of music that is expanding as a trend among adolescents, whose messages are not clearly discriminated or prosecuted and which tend to normalize certain discriminatory behaviors towards women and reinforce macho thinking among the male gender. For all these reasons, the educational system must promote the creation of a musical culture that invites adolescents to be aware of and critically judge the music they listen to daily.La música no es sólo un simple pasatiempo, pues también contribuye a la construcción de identidades, propicia el desarrollo cultural o genera estrechos lazos afectivos entre quienes comparten las mismas preferencias musicales. En los últimos años está adquiriendo una gran popularidad el reggaetón, un género musical admirado por la juventud y caracterizado por contener, en sus letras, mensajes discriminantes hacia la mujer. En este sentido, resulta de vital importancia cuestionar la repercusión ejercida en los/as adolescentes, donde ha calado con mayor ímpetu, analizando las posibles consecuencias que puede llegar a tener a la hora de construir o reforzar pensamientos machistas. Se plantea una investigación de corte cualitativo que trata de examinar las percepciones de los adolescentes. A través de dos grupos de discusión se debate y confrontan opiniones de jóvenes escolarizados en las etapas educativas de 2º de ESO y 3º de ESO de dos institutos de educación secundaria de la provincia de Huelva. Durante las sesiones de los grupos de discusión, los/as participantes ponen en tela de juicio la relación entre diferentes variables que emergen de las propiedades del lenguaje empleado en algunas letras del reggaetón, como son el machismo o la violencia de género. El análisis de los discursos derivados de las sesiones de trabajo se ha desarrollado a través del software Maxqda. Los resultados dejan entrever un tipo de música que se expande como una moda entre los adolescentes, cuyos mensajes no son claramente discriminados ni enjuiciados y que tienden a normalizar determinadas conductas discriminatorias hacia la mujer y a reforzar el pensamiento machista entre el género masculino. Por todo ello, desde el sistema educativo se ha de potenciar la creación de una cultura musical que invite a los adolescentes a ser conscientes y a enjuiciar críticamente la música que escuchan diariamente

Progress on the preparation of nanocrystalline apatites and surface characterization: Overview of fundamental and applied aspects

Nanocrystalline calcium phosphate apatites constitute the main inorganic part of hard tissues, and a growing focus is devoted to prepare synthetic analogs, so-called “biomimetic”, able to precisely mimic the morphological and physico-chemical features of biological apatite compounds. Both from fundamental and applied viewpoints, an accurate characterization of nanocrystalline apatites, including their peculiar surface features, and a deep knowledge of crystallization aspects are prerequisites to attempt understanding mineralization phenomena in vivo as well as for designing innovative bioactive materials that may then find applications in bone tissue engineering, either as self-supported scaffolds and fillers or in the form of coatings, but also in other domains such as drug delivery or else medical imaging. Also,interfacial phenomena are of prime importance for getting a better insight of biomineralization and for following the behavior of biomaterials in or close to their final conditions of use. In this view,both adsorption and ion exchange represent essential processes involving the surface of apatite nanocrystals, possibly doped with foreign elements or functionalized with organic molecules of interest. In this review paper, we will address these various points in details based on a large literature survey. We will also underline the fundamental physico-chemical and behavioral differences that exist between nanocrystalline apatites (whether of biological origin or their synthetic biomimetic analogs) and stoichiometric hydroxyapatite

An approximation property with respect to an operator ideal

Given an operator ideal A, we say that a Banach space X has the approximation property with respect to A if T belongs to {S ◦T : S ∈F(X)} τc for every Banach space Y and every T ∈A(Y,X), τc being the topology of uniform convergence on compact sets. We present several characterizations of this type of approximation property. It is shown that some of the existing approximation properties in the literature may be included in this setting

Duality of measures of non-A-compactness

Let A be a Banach operator ideal. Based on the notion of A-compactness in a Banach space due to Carl and Stephani, we deal with the notion of measure of non-A-compactness of an operator. We consider a map χA (respectively, nA) acting on the operators of the surjective (respectively, injective) hull of A such that χA(T) = 0 (respectively, nA(T) = 0) if and only if the operator T is A-compact (respectively, injectively A-compact). Under certain conditions on the ideal A, we prove an equivalence inequality involving χA(T∗) and nAd(T). This inequality provides an extension of a previous result stating that an operator is quasi p-nuclear if and only if its adjoint is p-compact in the sense of Sinha and Karn

Aplicación de metodología LEAN en un taller de mecanizado

Este trabajo de fin de grado propone la búsqueda de soluciones que permitan optimizar una línea de producción en serie. Buscamos reducir los despilfarros y encontrar aquellas actividades que no crean valor añadido para eliminarlas en la medida de lo posible. La creciente competencia, entre diferentes empresas y también entre diferentes factorías dentro del mismo grupo, hace que sea imprescindible la búsqueda de óptimos de calidad, precio y tiempo que nos permitan obtener ventajas competitivas respecto a otros fabricantes. Para la búsqueda de soluciones nos apoyaremos en las herramientas que nos proporciona la metodología de Lean Manufacturing o Toyota Production System. Nuestro campo de actuación se basará en la recopilación y análisis de datos de una línea de mecanizado, utilizando estos como punto de partida para la búsqueda de soluciones en un seminario de apertura Lean.Departamento de Organización de Empresas y Comercialización e Investigación de MercadosGrado en Ingeniería en Organización Industria