Normatives de nova aplicació en la producció i comercialització de carn picada i preparats de carn

Treball presentat a la Facultat de Veterinària de la Universitat Autònoma de Barcelona.Treball presentat a l'assignatura de Deontologia i Veterinària Legal (21223

Models de població del món i prediccions

En aquest treball pretenem predir com evolucionarà la població del món a partir de dades disponibles (estimades) de la població humana durant els darrers vint segles. Les fonts que hem utilitzat per a obtenir les dades en les que basarem el nostre estudi, són: el web del cens dels EEUU, el de la Divisió de Població del Departament d'Economia i Assumptes Socials de la ONU

Center problem for systems with two monomial nonlinearities

We study the center problem for planar systems with a linear center at the origin that in complex coordinates have a nonlinearity formed by the sum of two monomials. Our first result lists several centers inside this family. To the best of our knowledge this list includes a new class of Darboux centers that are also persistent centers. The rest of the paper is dedicated to try to prove that the given list is exhaustive. We get several partial results that seem to indicate that this is the case. In particular, we solve the question for several general families with arbitrary high degree and for all cases of degree less or equal than 19. As a byproduct of our study we also obtain the highest known order for weak-foci of planar polynomial systems of some given degrees

Limit cycles in the Holling-Tanner model

This paper deals with the following question: does the asymptotic stability of the positive equilibrium of the Holling-Tanner model imply it is also globally stable? We will show that the answer to this question is negative. The main tool we use is the computation of Poincaré-Lyapunov constants in case a weak focus occurs. In this way we are able to construct an example with two limit cycles

Rational parameterizations approach for solving equations in some dynamical systems problems

We show how the use of rational parameterizations facilitates the study of the number of solutions of many systems of equations involving polynomials and square roots of polynomials. We illustrate the effectiveness of this approach, applying it to several problems appearing in the study of some dynamical systems. Our examples include Abelian integrals, Melnikov functions and a couple of questions in Celestial Mechanics: the computation of some relative equilibria and the study of some central configurations

A primal-dual splitting algorithm for composite monotone inclusions with minimal lifting

In this work, we study resolvent splitting algorithms for solving composite monotone inclusion problems. The objective of these general problems is finding a zero in the sum of maximally monotone operators composed with linear operators. Our main contribution is establishing the first primal-dual splitting algorithm for composite monotone inclusions with minimal lifting. Specifically, the proposed scheme reduces the dimension of the product space where the underlying fixed point operator is defined, in comparison to other algorithms, without requiring additional evaluations of the resolvent operators. We prove the convergence of this new algorithm and analyze its performance in a problem arising in image deblurring and denoising. This work also contributes to the theory of resolvent splitting algorithms by extending the minimal lifting theorem recently proved by Malitsky and Tam to schemes with resolvent parameters.FJAA and DTB were partially supported by the Ministry of Science, Innovation and Universities of Spain and the European Regional Development Fund (ERDF) of the European Commission, Grant PGC2018-097960-B-C22. FJAA was partially supported by the Generalitat Valenciana (AICO/2021/165). RIB was partially supported by FWF (Austrian Science Fund), project P 34922-N. DTB was supported by MINECO and European Social Fund (PRE2019-090751) under the program “Ayudas para contratos predoctorales para la formación de doctores” 2019

Some results on homoclinic and heteroclinic connections in planar systems

Consider a family of planar systems depending on two parameters $(n,b)$ and having at most one limit cycle. Assume that the limit cycle disappears at some homoclinic (or heteroclinic) connection when $\Phi(n,b)=0.$ We present a method that allows to obtain a sequence of explicit algebraic lower and upper bounds for the bifurcation set ${\Phi(n,b)=0}.$ The method is applied to two quadratic families, one of them is the well-known Bogdanov-Takens system. One of the results that we obtain for this system is the bifurcation curve for small values of $n$, given by $b=\frac5 7 n^{1/2}+{72/2401}n- {30024/45294865}n^{3/2}- {2352961656/11108339166925} n^2+O(n^{5/2})$. We obtain the new three terms from purely algebraic calculations, without evaluating Melnikov functions

"I guess there's just a meanness in this world": Bruce Springsteen's Nebraska and the Abyss

Adopting the concept of 'the abyss' as the central theme of the album, the lyrics of Springsteen's Nebraska are analyzed in order to formulate an understanding of the concept of the abyss itself within the album. This interpretation includes, but is not limited to, an exploration of the nature of the abyss and its origins, its repercussions, and its "resolution" or lack thereof. Thus, this paper traces the interconnectedness of poverty, kinship, alienation, loss of agency, and the abyss in Nebraska's lyrics, and how the abyss can perhaps be traced back to the systems of oppression that subjugate Springsteen's characters.Adoptant el concepte de "l'abisme" com a tema central de l'àlbum, en aquesta tesi s'analitzen les lletres de Nebraska de Bruce Springsteen, per tal de formular tal concepte pel que fa a l'àlbum. Aquesta interpretació inclou una exploració de la naturalesa de l'abisme i els seus orígens, les seves repercussions, i la seva "resolució", o manca d'aquesta. Així doncs, es traça la interconnexió entre la pobresa, la família, l'alienació, la pèrdua de voluntat pròpia, i l'abisme a les lletres de Nebraska, i com els orígens de l'abisme es poden trobar en els sistemes d'opressió que subjuguen els personatges de Springsteen.Adoptando el concepto del "abismo" como tema central del álbum, en esta tesis se analizan las letras de Nebraska de Bruce Springsteen, con el fin de formular tal concepto respecto al álbum. Esta interpretación incluye una exploración de la naturaleza del abismo y sus orígenes, sus repercusiones, y su "resolución", o falta de esta. Así, se traza la interconexión entre la pobreza, la familia, la alienación, la pérdida de voluntad propia, i el abismo en las letras de Nebraska, y cómo los orígenes del abismo pueden encontrarse en los sistemas de opresión que subyugan a los personajes de Springsteen