Parabolic reaction-diffusion systems with nonlocal coupled diffusivity terms

In this work we study a system of parabolic reaction-diffusion equations which are coupled not only through the reaction terms but also by way of nonlocal diffusivity functions. For the associated initial problem, endowed with homogeneous Dirichlet or Neumann boundary conditions, we prove the existence of global solutions. We also prove the existence of local solutions but with less assumptions on the boundedness of the nonlocal terms. The uniqueness result is established next and then we find the conditions under which the existence of strong solutions is assured. We establish several bow-up results for the strong solutions to our problem and we give a criterium for the convergence of these solutions towards a homogeneous state.CAPES [BEX 2478-12-8]; MEC/MCTI/CAPES/CNPq/FAPs, Brazil [71/2013, 88881.030388/2013-01]; Fundacao para a Ciencia e a Tecnologia, Portugal [UID/MAT/04561/2013-2015]info:eu-repo/semantics/publishedVersio

Hans Kelsen and the tradition of natural law: why Kelsen’s objections to the natural-law doctrine does not apply against Aquinas’s theory of natural law

In his works, Hans Kelsen elaborates several objections to the so-called “doctrine of natural law”, especially in his essay The Natural-Law Doctrine Before the Tribunal of Science. Kelsen argues that natural law theorists, searching for an absolute criterion for justice, try to deduce from nature the rules of human behavior. Robert P. George, in the essay Kelsen and Aquinas on the ‘Natural Law Doctrine’ examines his criticism and concludes that what Kelsen understands as the Natural-law doctrine does not include the natural law theory elaborated by Thomas Aquinas. In this paper, we will try to corroborate George’s theses and try to show how Aquinas’ natural law theory can be vindicated against Kelsens criticisms

Continuous and discontinuous absorbing-state phase transitions on Voronoi-Delaunay random lattices

We study absorbing-state phase transitions in two-dimensional Voronoi-Delaunay (VD) random lattices with quenched coordination disorder. Quenched randomness usually changes the criticality and destroys discontinuous transitions in low-dimensional nonequilibrium systems. We performed extensive simulations of the Ziff-Gulari-Barshad (ZGB) model, and verified that the VD disorder does not change the nature of its discontinuous transition. Our results corroborate recent findings of Barghatti and Vojta [Phys. Rev. Lett. {\bf 113}, 120602 (2014)] stating the irrelevance of topological disorder in a class of random lattices that includes VD and raise the interesting possibility that disorder in nonequilibrium APT may, under certain conditions, be irrelevant for the phase coexistence. We also verify that the VD disorder is irrelevant for the critical behavior of models belonging to the directed percolation and Manna universality classes.Comment: 7 pages, 6 figure

A representação da personagem negra na literatura infantil juvenil latino-americana

II Jornadas Latino-Americanas de Linguagens e Cultura. Em comemoração aos 100 anos de nascimento de Roa Bastos e 50 anos da morte de Guimarães RosaO presente artigo tem por objetivo fazer um estudo sobre a imagem da cultura negra em obras literárias, com base em narrativas e ilustrações em torno da personagem feminina negra no sentido de verificar se as imagens reforçam ou não os estereótipos, a fim de verificar quais se aproximam dos propósitos da valorização feminina na cultura africana e afro-brasileira. Inicialmente será feito uma breve análise dessa literatura negra marcada por uma formação basicamente iniciamos com uma breve análise dessa literatura negra marcados por uma formação basicamente européia , com pouco ou nenhuma presença de negrosPrograma de Pós-Graduação em Literatura Comparada Programa de Pós-Graduação Interdisciplinar em Estudos Latino-Americanos Curso de Graduação em Letras – Artes e Mediação Cultura

Quebrando estereótipos: o papel do mediador na valorização do negro na literatura infantil

A presença de personagens negros na literatura infantil no Brasil esteve distante dos livros durante muito tempo, isso por conta de uma formação basicamente eurocêntrica. Somente na década de 1980, no Brasil, surgem os primeiros livros para o público infantil com protagonistas negros. De lá para cá, o mercado editorial alavancou com diversas obras com personagens negros representados. O objetivo dessas produções é desconstruir estereótipos negativos acerca dos mesmos na sociedade. Para que sejam desconstruídos tais estereótipos, é preciso não somente escolher uma boa história, mas também saber mediar às discussões/diálogos entre as crianças. A partir dessa perspectiva, esta comunicação tem como objetivo analisar o papel do mediador entre as crianças e os livros infantis com personagens femininas negras. O referencial teórico que embasa esta investigação está nas contribuições dos seguintes autores: Colomer (2007), Jovino (2006), Silva (1995), Petit (2008) entre outros.La presencia de personajes negros en la literatura infantil en Brasil estuvo distante de los libros durante mucho tiempo, eso por cuenta de una formación básicamente eurocéntrica. Sólo en la década de 1980, en Brasil surgen los primeros libros para el público infantil con protagonistas negros. De allí para allá, el mercado editorial apalancó con diversas obras con personajes negros representados. El objetivo de esas producciones es deconstruir estereotipos negativos a cerca de los mismos en la sociedad. Para que se deconstruir tales estereotipos, es necesario no sólo escoger una buena historia, sino también saber mediar a las discusiones / diálogos entre los niños. A partir de esta perspectiva, esta comunicación tiene como objetivo analizar el papel del mediador entre los niños y los libros infantiles con personajes femeninos negros. El referencial teórico que embasa esta investigación está en las contribuciones de los siguientes autores: Colomer (2007), Jovino (2006), Silva (1995), Petit (2008) entre otrosUniversidade Federal da Integração Latino Americana (UNILA-PR) e Universidade Estadual do Oeste do Paraná (UNIOESTE-PR

Firs under field extensions

Our main aim is to investigate the relation between free ideal rings (firs) which are algebras over a field and the rings obtained from them by a commutative field extension of scalars. Having in mind the monoid of projectives of these rings, we prove that commutative monoids with distinguished element which are conical and have the UGN property are strongly embedded in their coproduct and that the coproduct inherits some properties of its factors. This result, in conjunction with Bergman's coproduct theorems, is used to establish links between coproducts of skew fields and the rings obtained from them by extension of scalars. The notion of a power-free ideal ring is explored when looking at coproducts and, more generally, at rings obtained by matrix reduction of coproducts. We also look at firs of the form R = Fk(X), where F is either a finite Galois extension or a simple purely inseparable extension of k. These firs, when tensored with F over k, give rise to rings that are no longer firs, but they are very close to being full matrix rings over firs in the sense that the adjunction to R of a single inverse (in the purely inseparable case) or of finitely many inverses (in the Galois case) originates a ring which under the same extension of scalars is a full matrix ring over a fir. The universal field of fractions of a fir obtained by this construction is just the skew field component of the simple artinian ring obtained by extending the scalars of the universal field of fractions of R