Search results for "XX"
showing 10 items of 460 documents
La Asociación Europea contra la Poliomielitis y los programas europeos de vacunación
2012
La búsqueda de una respuesta europea al problema planteado por los brotes epidémicos de poliomielitis en las décadas centrales del siglo XX, desembocó en la creación de un organismo nuevo, la Asociación Europea contra la Poliomielitis en 1951. Los mecanismos de funcionamiento interno y las conexiones internacionales de dicha Asociación fueron subsidiarios de un determinado contexto socio-político que propiciaba este tipo de consorcios. Como muestra este trabajo, su labor en los dieciocho años de existencia fue decisiva para la articulación y el éxito alcanzado por las políticas sanitarias nacionales de inmunización masiva frente a la enfermedad.
Partial inner product spaces: Some categorical aspects
2012
We make explicit in terms of categories a number of statements from the theory of partial inner product spaces (PIP spaces) and operators on them. In particular, we construct sheaves and cosheaves of operators on certain PIP spaces of practical interest.
On cubic elliptic varieties
2013
Let X->P^(n-1) be an elliptic fibration obtained by resolving the indeterminacy of the projection of a cubic hypersurface Y of P^(n+1) from a line L not contained in Y. We prove that the Mordell-Weil group of the elliptic fibration is finite if and only if the Cox ring of X is finitely generated. We also provide a presentation of the Cox ring of X when it is finitely generated.
Algebraic aspects and coherence conditions for conjoined and disjoined conditionals
2019
We deepen the study of conjoined and disjoined conditional events in the setting of coherence. These objects, differently from other approaches, are defined in the framework of conditional random quantities. We show that some well known properties, valid in the case of unconditional events, still hold in our approach to logical operations among conditional events. In particular we prove a decomposition formula and a related additive property. Then, we introduce the set of conditional constituents generated by $n$ conditional events and we show that they satisfy the basic properties valid in the case of unconditional events. We obtain a generalized inclusion-exclusion formula and we prove a …
Expansions of the solutions of the confluent Heun equation in terms of the incomplete Beta and the Appell generalized hypergeometric functions
2015
We construct several expansions of the solutions of the confluent Heun equation in terms of the incomplete Beta functions and the Appell generalized hypergeometric functions of two variables of the first kind. The coefficients of different expansions obey four-, five-, or six-term recurrence relations that are reduced to ones involving less number of terms only in a few exceptional cases. The conditions for deriving finite-sum solutions via termination of the series are discussed.
Quantum moment maps and invariants for G-invariant star products
2002
We study a quantum moment map and propose an invariant for $G$-invariant star products on a $G$-transitive symplectic manifold. We start by describing a new method to construct a quantum moment map for $G$-invariant star products of Fedosov type. We use it to obtain an invariant that is invariant under $G$-equivalence. In the last section we give two simple examples of such invariants, which involve non-classical terms and provide new insights into the classification of $G$-invariant star products.
Asymptotic analysis of the form-factors of the quantum spin chains
2020
Since a long-time, the quantum integrable systems have remained an area where modern mathematical methods have given an access to interesting results in the study of physical systems. The exact computations, both numerical and asymptotic, of the correlation function is one of the most important subject of the theory of the quantum integrable models. In this context an approach based on the calculation of form factors has been proved to be a more effective one. In this thesis, we develop a new method based on the algebraic Bethe ansatz is proposed for the computation of the form-factors in thermodynamic limit. It is applied to and described in the context of isotropic XXX Heisenberg chain, w…
La transmissió lingüística intergeneracional a Castelló de la Plana i la Franja: La rellevància dels usos entre progenitors
2020
Fa 50 anys, a Conflicte lingüístic valencià, Rafael L. Ninyoles situava el trencament de la transmissió familiar del català com a resultat i manifestació externa de conflictes socials i de classes, especialment visibles enmig del procés de modernització econòmica i mobilitat social accelerada del País Valencià dels anys 60 del segle XX. En aquest article partim de dos estudis de cas quantitatius sobre la transmissió intergeneracional de les llengües a Castelló de la Plana i les comarques centrals de la Franja per a actualitzar el seu diagnòstic i matisar la visió d'aquest fenomen com a resultat de decisions dels progenitors imposades verticalment a la descendència. Hi proposem que els usos …
Ramón, Tzara e Dada
2020
Un estudio sobre la relación entre Ramón Gómez de la Serna y el fundador de Dada; Tristan Tzara.