Método Gráfico para establecer el campo de pendientes de una Ecuación Diferencial

Trabajo orientado en el área de ecuaciones diferenciales enfocándose en el método gráfico para establecer el campo de pendiente de una ecuación diferencial y el método de aproximaciones numéricas para aproximar la solución de una ecuación diferencial. Presenta los métodos de Euler, Runge-Kutta de cuarto orden y el método multipasos de Adams-Bashforth-Moulton. Asimismo, se explica las ecuaciones mediante el uso del software para los métodos gráficos tales como el Maple y Geogebra.

X-Ray powder diffraction laboratory @ University of Málaga (UMA)

X-Ray Powder Diffraction (XRPD) laboratory is a facility placed at Servicios Centrales de apoyo a la Investigación (SCAI) at University of Malaga (UMA) http://www.scai.uma.es/. This facility has three XRPD diffractometers and a diffractometer to measure high-resolution thin-films. X´Pert PRO MPD from PANalytical. This is a bragg-brentano (theta/2theta) with reflection geometry diffractometer which allows to obtain high resolution XRPD data with strictly monochromatic CuKα1 radiation (λ=1.54059Å) [Ge(111) primary monochromator] and an automatic sample charger. Moreover, it has parallel monochromatic CuKα1 radiation (λ=1.54059Å) with an hybrid Ge(220) monochromator for capillary and multiproposal (bulk samples up to 1 Kg) sample holders. The HTK1200N chamber from Anton Paar allows collecting high resolution high temperature patterns. EMPYREAN from PANalytical. This diffractometer works in reflection and transmission geometries with theta/theta goniometer, using CuKα1,2 radiation (λ=1.5418Å), a focusing X-ray mirror and a ultra-fast PIXCEL 3D detector with 1D and 2D collection data modes (microstructural and preferred orientation analysis). Moreover, the TTK450N chamber allows low temperature and up to 450ºC studies. A D8 ADVANCE (BRUKER) was installed in April 2014. It is the first diffractometer in Europe equipped with a Johansson Ge(111) primary monochromator, which gives a strictly monochromatic Mo radiation (λ=0.7093 Å) [1]. It works in transmission mode (with a sample charger) with this high resolution configuration. XRPD data suitable for PDF (Pair Distribution Function) analysis can be collected with a capillary sample holder, due to the high energy and high resolution capabilities of this diffractometer. Moreover, it has a humidity chamber MHC-trans from Anton Paar working on transmission mode with MoKα1 (measurements can be collected at 5 to 95% of relative humidity (from 20 to 80 ºC) and up to 150ºC [2]). Furthermore, this diffractometer also has a reaction chamber XRK900 from Anton Paar (which uses CuKα1,2 radiation in reflection mode), which allows data collection from room temperature to 900ºC with up to 10 bar of different gases. Finally, a D8 DISVOVER A25 from BRUKER was installed on December 2014. It has a five axis Euler cradler and optics devices suitable for high resolution thin film data collection collected in in-plane and out-of-plane modes. To sum up, high-resolution thin films, microstructural, rocking-curve, Small Angle X-ray Scattering (SAXS), Grazing incident SAXS (GISAXS), Ultra Grazing incident diffraction (Ultra-GID) and microdiffraction measurements can be performed with the appropriated optics and sample holders. [1] L. León-Reina, M. García-Maté, G. Álvarez-Pinazo, I. Santacruz, O. Vallcorba, A.G. De la Torre, M.A.G. Aranda “Accuracy in Rietveld quantitative phase analysis: a comparative study of strictly monochromatic Mo and Cu radiations” J. Appl. Crystallogr. 2016, 49, 722-735. [2] J. Aríñez-Soriano, J. Albalad, C. Vila-Parrondo, J. Pérez-Carvajal, S. Rodríguez-Hermida, A. Cabeza, F. Busqué, J. Juanhuix, I. Imaz, Daniel Maspoch “Single-crystal and humidity-controlled powder diffraction study of the breathing effect in a metal-organic framework upon water adsorption/desorption” Chem. Commun., 2016, DOI: 10.1039/C6CC02908F.

Funciones elípticas. La función seno generalizado

Durante varios años Gabriel Pareja estuvo buscando la llave que abre el bruñido cofre de las funciones elípticas. Como dedicado profesor de Cálculo, Gabriel buscaba sobre todo una manera sencilla de explicarlas a sus alumnos. Y un día del año 2011, alentado por un conocido maestro ruso, le fue revelada la respuesta evidente que no se dejaba ver: las funciones elípticas han de entenderse como una generalización de las funciones circulares. Desde aquel día, sus dos compañeros de trabajo y él mismo se dieron a la tarea de escribir un libro que explicara cabalmente los fundamentos de las funciones elípticas y que, a la vez, recreara su circunstancia histórica desde Euler hasta Jacobi. Dicho libro es el que el lector tiene ahora en sus manos. Con esta publicación pulimos los resultados de nuestro libro anterior titulado Integrales elípticas con notas históricas, en el que nos dedicamos más a las integrales y al estado del arte de la disciplina en el siglo XVIII. Este nuevo libro contiene, además, algunos resultados del proyecto de investigación La emergencia de las funciones elípticas en la primera mitad del siglo XIX, que ha sido cofinanciado por el Comité Central de Investigaciones de la Universidad del Tolima y la Vicerrectoría de Investigaciones de la Universidad de Medellín. Esta vez tenemos también mayor dominio de la técnica de escribir a tres manos. El libro se ha marinado y cocinado muy lentamente.

Error estimation and adaptive mesh refinement for aerodynamic flows

This lecture course covers the theory of so-called duality-based a posteriori error estimation of DG finite element methods. In particular, we formulate consistent and adjoint consistent DG methods for the numerical approximation of both the compressible Euler and Navier-Stokes equations; in the latter case, the viscous terms are discretized based on employing an interior penalty method. By exploiting a duality argument, adjoint-based a posteriori error indicators will be established. Moreover, application of these computable bounds within automatic adaptive finite element algorithms will be developed. Here, a variety of isotropic and anisotropic adaptive strategies, as well as $hp$-mesh refinement will be investigated.

Classification of plant communities, structure and diversity of forests in Acre, Brazil.

2016

HEAT MANAGEMENT IN THE PUMPING INFRASTRUCTURE AREA OF AN ESTERHAZY MINE

Heat management in mines is a growing issue as mines expand physically in size and depth and as the infrastructure grows that is required to maintain them. Heat management is a concern as it relates to the health and safety of the workers as set by the regulations of governing bodies as well as the heat sensitive equipment that may be found throughout the mine workings. In order to reduce the exposure of working in hot environments there are engineering and management systems that can monitor and control the environmental conditions within the mine. The successful implementation of these methods can manage the downtime caused by heat stress environments, which can increase overall production. This thesis introduces an approach to monitoring and data based heat management. A case study is presented with an in depth approach to data collection. Data was collected for a period of up to and over one year. Continuous monitoring was conducted by equipment that was developed both commercially and within the mine site. The monitoring instrumentation was used to assess the environmental conditions found within the study area. Analysis of the data allowed for an engineering assessment of viable options in order to control and manage the environment heat stress. An option is developed and presented which allows for the greatest impact on the heat stress conditions within the case study area and is economically viable for the mine site.

Measure-valued mass evolution problems with flux boundary conditions and solution-dependent velocities

In this paper we prove well-posedness for a measure-valued continuity equation with solution-dependent velocity and flux boundary conditions, posed on a bounded one-dimensional domain. We generalize the results of an earlier paper [J. Differential Equations, 259 (2015), pp. 10681097] to settings where the dynamics are driven by interactions. In a forward-Euler-like approach, we construct a time-discretized version of the original problem and employ those results as a building block within each subinterval. A limit solution is obtained as the mesh size of the time discretization goes to zero. Moreover, the limit is independent of the specific way of partitioning the time interval [0, T]. This paper is partially based on results presented in Chapter 5 of [Evolution Equations for Systems Governed by Social Interactions, Ph.D. thesis, Eindhoven University of Technology, 2015], while a number of issues that were still open there are now resolved.

Floresta Estadual do Amapá: uma unidade de conservação sob ameaça.

2016

O acordo de Paris e o futuro do REDD+ no Brasil.

O Acordo do Clima é um marco nas negociações internacionais deste século. É fato que o aquecimento global ameaça o bem-estar humano e a economia mundial, e o desafio de estabilizar a concentração de gases do efeito estufa (GEE) na atmosfera, limitando o aumento de temperatura a menos de 2 graus Celsius até 2100, é uma responsabilidade comum, mas as ações devem ter caráter diferenciado dependendo da contribuição histórica e capacidade de cada nação. Para isso será necessária uma mudança de paradigma em relação ao modelo de desenvolvimento vigente, sobretudo a transição da matriz energética baseada nos combustíveis fósseis, em direção a uma economia com predominância de fontes renováveis e de baixa emissão de carbono. O processo de negociação do acordo climático foi longo. Em 1992, o Brasil sediou a primeira Conferência das Nações Unidas sobre o Meio Ambiente e o Desenvolvimento, vinte anos depois da Primeira Conferência Mundial sobre o Homem e o Meio Ambiente (Estocolmo, 1972) que pela primeira vez chamou atenção da comunidade internacional sobre a necessidade de um pacto global para reverter as ameaças à saúde do planeta e das futuras gerações. A Eco-92 celebrou uma série de tratados relacionados à temática ambiental, dentre eles a Convenção-Quadro sobre Mudança do Clima, que abriu caminho para o Protocolo de Quioto. Pela primeira vez, se propõe um calendário pelo qual países-membros tem a obrigação3 de reduzir a emissão de GEE em, pelo menos, 5% em relação aos níveis de 1990 no período entre 2008 e 2012. O Protocolo traz a opção dos países do Anexo I compensarem suas emissões através do Mecanismo de Desenvolvimento Limpo (MDL), considerando como medida de redução projetos implementados nos países em desenvolvimento (PED). Sua ratificação só ocorreu em 2005 com a entrada da Rússia, mas ainda sem a participação dos Estados Unidos e China, responsáveis pelas maiores fontes de emissões planetárias. O Brasil teve um papel de liderança nas negociações da Convenção do Clima, principalmente a partir de 2009, quando apresenta a UNFCCC a sua Política Nacional sobre Mudança do Clima (PNMC, Lei no 12.187/2009) e posteriormente o Plano Nacional sobre Mudança do Clima (Decreto 7390/2010). Estes marcos regulatórios definiram a estratégia brasileira de redução voluntária de emissões de GEE (36,1 à 38,9% em relação às emissões projetadas até 2020) e os planos de ação setoriais para atingir tais metas. Apesar de todos os desafios sociais e econômicos, os resultados alcançados pelo Brasil no período de vigência do Protocolo de Quioto representam um dos maiores esforços de um único país até hoje, tendo reduzido suas emissões em mais de 41%, em 2012, com relação aos níveis de 2005. A região amazônica teve papel decisivo, com redução de 85% do desmatamento, enquanto todos os demais setores da economia tiveram aumento de emissões. No Acordo de Paris, o Brasil sinaliza um compromisso ainda mais audacioso de redução de emissões absolutas, e de zerar o desmatamento ilegal em 2030 (iNDC, 2015). Este artigo pretende fazer um retrospecto da construção da proposta do mecanismo de redução de emissões por desmatamento e degradação (REDD) no Brasil e na Conferência das Nações Unidas sobre Mudanças Climáticas, e discutir o papel das florestas tropicais no combate ao aquecimento global do ponto de vista da relevância da região amazônica para o alcance das metas brasileiras, e o contexto de discussão e implementação de REDD+ nos estados. Finalmente refletir sobre os desafios futuros da recém lançada Estratégia Nacional de REDD+ (ENREDD+) frente ao baixo retorno histórico recebido pelas populações amazônidas quando analisamos o seu legado na conservação deste imenso patrimônio da humanidade. E a visão traçada pelo Brasil na sua Pretendida Contribuição Nacionalmente Determinada (iNDCs), como parte do novo Acordo do Clima, onde o papel das florestas torna-se secundário em relação ao agronegócio.

O PAPEL DA COMUNICAÇÃO FACE A FACE NAS ORGANIZAÇÕES NO CONTEXTO DA SOCIEDADE MIDIATIZADA

Este estudo trata da comunicação face a face nas organizações sob diferentes abordagens teóricas. Considera a perspectiva da simultaneidade dos meios, já que as empresas utilizam diversos canais para dialogar com seus públicos de interesse. Leva em conta o fenômeno da midiatização, que reestrutura o modo como as pessoas se relacionam na sociedade contemporânea. O objetivo geral da pesquisa é sistematizar papeis potencialmente exercidos pela interação face a face e conhecer algumas circunstâncias que envolvem sua prática nas organizações. Por se tratar de uma tese teórica, a pesquisa bibliográfica se apresenta como um dos principais procedimentos metodológicos; análises de casos empíricos e um estudo de caso desenvolvido na Embrapa Pantanal constituem situações ilustrativas. Conclui-se que a comunicação face a face nas empresas ocorre de forma simultânea e combinada a outros canais de comunicação, porém, ela proporciona resultados práticos e filosóficos ainda pouco explorados. É rara a utilização estratégica de contatos presenciais como mecanismo para estabelecer relacionamentos, conhecer as reações alheias e ajustar a comunicação, aliar o discurso corporativo às práticas empresariais e avaliar o contexto onde se desenvolvem as interações, o que pode ser decisivo para a comunicação organizacional.

Effective field theories and their phenomenological applications

Effective field theories (EFTs) are ubiquitous in theoretical physics and in particular in field theory descriptions of quantum systems probed at energies much lower than one or few characterizing scales. More recently, EFTs have gained a prominent role in the study of fundamental interactions and in particular in the parametriasation of new physics beyond the Standard Model, which would occur at scales Λ, much larger than the electroweak scale. In this thesis, EFTs are employed to study three different physics cases. First, we consider light-by-light scattering as a possible probe of new physics. At low energies it can be described by dimension-8 operators, leading to the well-known Euler-Heisenberg Lagrangian. We consider the explicit dependence of matching coefficients on type of particle running in the loop, confirming the sensitiveness to the spin, mass, and interactions of possibly new particles. Second, we consider EFTs to describe Dark Matter (DM) interactions with SM particles. We consider a phenomenologically motivated case, i.e., a new fermion state that couples to the Hypercharge through a form factor and has no interactions with photons and the Z boson. Results from direct, indirect and collider searches for DM are used to constrain the parameter space of the model. Third, we consider EFTs that describe axion-like particles (ALPs), whose phenomenology is inspired by the Peccei-Quinn solution to strong CP problem. ALPs generically couple to ordinary matter through dimension-5 operators. In our case study, we investigate the rather unique phenomenological implications of ALPs with enhanced couplings to the top quark.

A Unified Model for XVA, including Interest Rates and Rating

We start in Chapter 2 to investigate linear matrix-valued SDEs and the Itô-stochastic Magnus expansion. The Itô-stochastic Magnus expansion provides an efficient numerical scheme to solve matrix-valued SDEs. We show convergence of the expansion up to a stopping time τ and provide an asymptotic estimate of the cumulative distribution function of τ. Moreover, we show how to apply it to solve SPDEs with one and two spatial dimensions by combining it with the method of lines with high accuracy. We will see that the Magnus expansion allows us to use GPU techniques leading to major performance improvements compared to a standard Euler-Maruyama scheme. In Chapter 3, we study a short-rate model in a Cox-Ingersoll-Ross (CIR) framework for negative interest rates. We define the short rate as the difference of two independent CIR processes and add a deterministic shift to guarantee a perfect fit to the market term structure. We show how to use the Gram-Charlier expansion to efficiently calibrate the model to the market swaption surface and price Bermudan swaptions with good accuracy. We are taking two different perspectives for rating transition modelling. In Section 4.4, we study inhomogeneous continuous-time Markov chains (ICTMC) as a candidate for a rating model with deterministic rating transitions. We extend this model by taking a Lie group perspective in Section 4.5, to allow for stochastic rating transitions. In both cases, we will compare the most popular choices for a change of measure technique and show how to efficiently calibrate both models to the available historical rating data and market default probabilities. At the very end, we apply the techniques shown in this thesis to minimize the collateral-inclusive Credit/ Debit Valuation Adjustments under the constraint of small collateral postings by using a collateral account dependent on rating trigger.

Analytic models of self-gravitating rotating gaseous tori with central black hole

In this thesis project, I present stationary models of rotating fluids with toroidal distributions that can be used to represent the active galactic nuclei (AGN) central obscurers, i.e. molecular tori (Combes et al., 2019), as well as geometrically thick accretion discs, like ADAF discs (Narayan and Yi, 1995) or Polish doughnuts (Abramowicz, 2005). In particular, I study stationary rotating systems with a more general baroclinic distribution (with a vertical gradient of the angular velocity), which are often more realistic and less studied, due to their complexity, than the barotropic ones (with cylindrical rotation), which are easier to construct. In the thesis, I compute analytically the main intrinsic and projected properties of the power-law tori based on the potential-density pairs of Ciotti and Bertin (2005). I study the density distribution and the resulting gravitational potential for different values of α, in the range 2 < α < 5. For the same models, I compute the surface density of the systems when seen face-on and edge-on. I then apply the stationary Euler equations to obtain rotational velocity and temperature distributions of the self-gravitating models in the absence of an external gravitational potential. In the thesis I also consider the power-law tori with the presence of a central black hole in addition to the gas self-gravity, and solving analytically the stationary Euler equations, I compute how the properties of the system are modified by the black hole and how they vary as a function of the black hole mass. Finally, applying the Solberg-Høiland criterion, I show that these baroclinic stationary models are linearly stable in the absence of the black hole. In the presence of the black hole I derive the analytical condition for stability, which depends on α and on the black hole mass. I also study the stability of the tori in the hypothesis that they are weakly magnetized, finding that they are always unstable to this instability.