A Human Rights Approach to Corporate Accountability and Environmental Litigation

This Comment explores how a human rights approach would provide a more efficient means of achieving compensation and deterring environmental law violations

Mathematical modeling and numerical simulation of a bioreactor landfill using Feel++

In this paper, we propose a mathematical model to describe the functioning of a bioreactor landfill, that is a waste management facility in which biodegradable waste is used to generate methane. The simulation of a bioreactor landfill is a very complex multiphysics problem in which bacteria catalyze a chemical reaction that starting from organic carbon leads to the production of methane, carbon dioxide and water. The resulting model features a heat equation coupled with a non-linear reaction equation describing the chemical phenomena under analysis and several advection and advection-diffusion equations modeling multiphase flows inside a porous environment representing the biodegradable waste. A framework for the approximation of the model is implemented using Feel++, a C++ open-source library to solve Partial Differential Equations. Some heuristic considerations on the quantitative values of the parameters in the model are discussed and preliminary numerical simulations are presented

Une méthode mixte multi-échelles pour un simulateur de réservoir biphasé

A multiscale hybrid mixed finite element method is presented in this paper to solve two-phase flow equations on heterogeneous media under the effect of gravitational segregation. It is designed to cope with the complex geometry and inherent multiscale nature of the rocks, leading to stable and accurate multi-physics reservoir simulations. This multiscale approach makes use of coarse scale fluxes between subregions (macro domains) that allow to reduce substantially the dominant computational costs associated with the flux/pressure kernel embedded in the numerical model. As such, larger scale problems can be approximated in a reasonable computational time. Dividing the problems into macro domains leads to a hierarchy of meshes and approximation spaces, allowing the efficient use of static condensation and parallel computation strategies. The method documented in this work utilizes discretizations based on a general domain partition formed by poly-hedral subregions. The normal flux between these subregions is associated with a finite dimensional trace space. The global system to be solved for the fluxes and pressures is expressed only in terms of the trace variables and of a piecewise constant pressure associated with each subregion. The fine scale features are resolved by mixed finite element approximations using fine flux and pressure representations inside each subregion, and the trace variable (i.e. normal flux) as Neumann boundary conditions. This property implies that the flux approximation is globally H(div)-conforming, and, as in classical mixed formulations, local mass conservation is observed at the micro-scale elements inside the subregions, an essential property for flows in heterogeneous media

The Measurement of Growth under Embodied Technical Change

New U.S. evidence from NIPA contradicts some of the well-known Kaldor stylized facts, and call for a reformulation of the modem theory of economic growth. Among these new facts, two must be stressed : A permanent decline in the relative price of durable goods, and a permanent increase in the real equipment to real GDP ratio. To be consistent with these new facts, growth models must include at least two sectors and address the problem of defining aggregate output. In this paper, the economic theory of index numbers is used to define the growth rate of real output in a growth model with embodied technical change. The main findings are : (i) NIPA's methodology measures growth in accordance with the economic theory on index numbers, and (ii) when the growth rate is measured as in NIPA, the contribution of embodied technical change to per capital GDP growth in the U.S. is 69%, which reinforce the claim that embodied technical change is important for growth.Embodied technical change, Growth facts, Growth accounting, Index number theory

Une méthode hybride multi-échelles pour les problèmes de Darcy utilisant des solveurs locaux à éléments finis mixtes

International audienceMultiscaled Hybrid Mixed (MHM) method refers to a numerical technique targeted to approximate systems of differential equations with strongly varying solutions. For fluid flows, normal fluxes (multiplier) over macro element boundaries, and coarse piecewise constant potential approximations in each macro element are computed (upscaling). Then, small details are resolved by local problems, using fine representations inside the macro elements, setting the multiplier as Neumann boundary conditions (downscaling). In this work a variant of the method is developed, denoted by MHM-H(div), adopting mixed finite elements at the dowscaling stage, instead of continuous finite elements used in all previous publications of the method. Thus, this alternative MHM method inherits improvements typical of mixed methods, as better flux accuracy, and local mass conservation at the mi-cro scale level inside the macro elements, which are important properties for multi-phase flows in rough heterogeneous media. Different two-scale stable space settings are considered. Vector face functions are supposed to have normal components restricted to a given finite dimensional trace space defined over the macro element boundaries. In each macro element, the internal flux components, with vanishing normal traces, and the potential approximations, may be enriched in different extents: with respect to internal mesh size, internal polynomial degree, or both, the choice being determined by the problem at hands. A unified general error analysis of the MHM-H(div) method is presented for all these two-scale space scenarios. Both MHM versions are compared for 2D test problems, with smooth solutions, for convergence rates verification, and for a Darcy's flow in heterogeneous media. MHM-H(div) 3D simulations are presented for a known singular Darcy's solution, using adaptive macro partitions, and for an oscillatory permeability scenario

High-order composite finite element exact sequences based on tetrahedral-hexahedral-prismatic-pyramidal partitions

The combination of tetrahedral and hexahedral elements in a single conformal mesh requires pyramids or prisms to make the transition between triangular and quadrilateral faces. This paper presents high order exact sequences of finite element approximations in H^1 (Ω), H(curl, Ω), H(div, Ω), and L^2(Ω) based on such kind of three dimensional mesh configurations. The approach is to consider composite polynomial approximations based on local partitions of the pyramids into two or four tetrahedra. The traces associated with triangular faces of these tetrahedral elements are constrained to match the quadrilateral shape functions on the quadrilateral face of the pyramid, in order to maintain conformity with shared neighboring hexahedron, or prism. Two classes of composite exact sequences are constructed, one using classic Nédélec spaces of first kind, and a second one formed by enriching these spaces with properly chosen higher order functions with vanishing traces. Projection-based interpolants satisfying the commuting diagram property are presented in a general form for each type of element. The interpolants are expressed as the sum of linearly independent contributions associated with vertices, edges, faces, and volume, according to the kind of traces appropriate to the space under consideration. Furthermore, we study applications to the mixed formulation of Darcy's problems based on compatible pairs of approximations in {H(div, Ω), L^2 (Ω)} for such tetrahedral-hexahedral-prismatic-pyramidal meshes. An error analysis is outlined, showing same (optimal) orders of approximation in terms of the mesh size as one would obtain using purely hexahedral or purely tetrahedral partitions. Enhanced accuracy for potential and flux divergence variables are obtained when enriched space configurations are applied. The predicted convergence orders are verified for some test problems

Interpretación dendrocronológica en tres especies tropicales en una selva baja caducifolia de Morelos

En este trabajo se estudiaron tres especies de selva baja caducifolia con posible potencial para estudios dendrocronológicos: Bursera lancifolia, Bursera aptera, y Bursera morelensis. Estas especies tienen bandas de crecimiento (anillos) distinguibles tanto a nivel visual como microscópico. Los anillos de las tres especies se caracterizaron a ambos niveles y se propuso fecharlos con métodos dendrocronológicos. Una vez fechados los núcleos de crecimiento, se realizó un análisis dendroclimatológico, comparando datos de precipitación, temperatura promedio y la cronología de anillo total. El programa dendrocronológico de control de calidad COFECHA determinó correlaciones significativas de periodicidad de anillos en Bursera lancifolia indicativo de un buen codatado entre núcleos de crecimiento. En las otras dos especies se observó la formación de anillos al igual que en Bursera lancifolia, los cuales se delimitaron y fecharon, pero de acuerdo al COFECHA no fueron significativas, lo que puede ser debido a una alta irregularidad en crecimiento de los anillos anuales entre diferentes especímenes de la misma especie. Se tomaron diez núcleos que codataron y diez núcleos que no lo hicieron todos procedentes de los mismos árboles. En los núcleos seleccionados se pulieron los dos cm externos que corresponden a los anillos formados recientemente (zona de la albura). Los anillos de crecimiento se identificaron a nivel microscópico y se midieron, comprobando su calidad de datado con el programa COFECHA. Los anillos analizados con el método dendrocronologico estándar y medidos con el micrométro, codataron no así los analizados con el microscopio óptico, situación que se atribuye al escaso tamaño de muestra y a la irregularidad en los crecimientos producto de madera de tensión y compresión, pues los árboles seleccionados se encontraban en una ladera. Las tres especies estudiadas presentaron anillos de crecimiento, indicativo de su potencial para estudios dendrocronológico

Aesthetic Misdiagnoses: Biomedicine, Homosexualities, and Medical Cultures in Mexico, 1953-2006

This dissertation examines the role of scientific and medical disciplines in the construction of homosexuality in Mexico, and how non-normative gender and sexual subjects engaged in political activism, body modifications, and aesthetic production to challenge the pathologizing discourses reinforced by the increasing authority of the biomedical sciences. Chapter 1 examines the role of photography as a medical instrument in the first documented sex-reassignment treatment in the Western Hemisphere performed by Mexican physician and sexologist Rafael Sandoval Camacho in the early 1950s, and how his patient Marta Olmos, Mexico’s first transsexual woman, embraced photojournalism as a medium to document, archive, and validate her identity as a woman. In chapter 2, I examine the popular phenomenon of publishing photographs of erotized trans sex workers known as Mujercitos during the 1970s in Alarma!, Mexico’s most influential crime tabloid magazine, and how these marginalized subjects appropriated biomedical technologies like “sex hormones” intended to regulate gender and sexual deviance to construct bodily identities that challenged the medical and criminological positions on the essentialist natures of gender expression, sexual desire, and the sexed body. Chapter 3 examines the early gay narrative of Luis Zapata and José Rafael Calva that emerged in conjunction to Mexico’s Homosexual Liberation Movement in the late 1970s. My analysis demonstrates how Zapata’s El vampiro de la colonia Roma [Adonis García: A Picaresque Novel] (1979), and Calva’s Utopía gay [Gay Utopia] (1983) present sharp critiques shared by Mexico’s homosexual liberation groups on the growing authority of disciplines like psychiatry, psychoanalysis, and biomedicine in pathologizing homosexuality. Chapter 4 examines the changing understandings of homosexuality, homosexual desire, and the homosexual body during the HIV/AIDS crisis through the work of Julio Galán, Nahum B. Zenil, and art collective Taller Documentación Visual. My analysis presents the role of the HIV virus not as an explicit visual reference but rather as an elusive, spectral, and dangerous entity that is identifiable through the aesthetic and formal composition of the artists’ works, best exemplified by the references to condoms as physical and symbolic devices in the mediation of gay sexual contact and desire. This dissertation demonstrates the critical roles of biomedicine, criminology, sexology, and psychiatry in regulating diverse forms of Mexican homosexualities, while simultaneously functioning as liminal disciplines strategically adopted by homosexual subjects to redefine, shape, and validate their desired bodily, sexual, and subjective identities

Aproximação numérica do problema de reativação de falha usando poroelasticidade linear

Orientador: Philippe Remy Bernard DevlooDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica e Instituto de GeociênciasResumo: A reativação de falhas, resultante de variações na pressão de poros, pode ocasionar atividades sísmicas, subsidência, dano nos poços e criação de caminhos de escape dos fluidos contidos nos reservatórios. Para se garantir uma produção de hidrocarbonetos eficiente, mostra-se um fator crítico a avaliação das tendências de reativação das falhas existentes no meio poroso. Neste trabalho, apresenta-se uma aproximação numérica para uma análise de deformação quase-estática com escoamento monofásico, considerando a compressibilidade da rocha e dos fluidos. Um modelo bidimensional foi empregado considerando a teoria de poroelasticidade linear e um novo tratamento da poroelasticidade através de estruturas de dados multifísicos. Formas adimensionais das equações de poroelasticidade são apresentadas, juntamente com a reprodução de diversas soluções analíticas e semi-analíticas das mesmas em semiespaços, com o propósito de se validar o algoritmo desenvolvido. O modelo computacional foi utilizado para avaliar as mudanças de tensão, no reservatório e em suas fronteiras, com o objetivo de se estudar as tendências reativação de falhas em diferentes cenários. As tendências de reativação de falhas, resultantes da indução de variações de tensão na rocha, foram calculadas através do método de variação de tensão de ruptura de Coulomb para a definição das seções com potencial de deslocamento por tensões cisalhante das falhas pre-existentes em tempos específicos, associados com as alterações na pressão de poros. Mostrou-se que a reativação de falhas depende da geometria de reservatório, das propriedades poroelásticas da rocha, coeficiente de atrito e a distribuição da pressão de poros. Um estudo sobre precisão dos cálculos baseado na dimensão do material circundante é apresentada e vários cenários com diferentes programas depleção foram avaliados para determinar a influência das taxas de produção sobre a tendência de reativação das falhasAbstract: Fault reactivation resulting from pore pressure changes may be accompanied by seismic activity, subsidence, well damage and the creation of fluid leakage paths. To ensure acceptable reservoir performance in hydrocarbon production, it is critical to assess the reactivation tendencies of existing faults. In this work, a numerical approximation is presented that allows quasi-static deformation coupled with monophasic flow considering compressible constituents. Two dimensional modeling is carried out using the theory of linear poroelasticity and a new treatment of poroelastic equations defined into a multiphysics data structure. Dimensionless forms of poroelasticity equations are presented and several analytic and semi analytic solutions, as well as poroelastic inclusion theory were reproduced with the proposed implementation in order to validate it. The computational model is used to evaluate the stress changes around and into the reservoir in order to assess the fault reactivation tendency at different scenarios. Fault reactivation tendency resulting from induced stress changes was calculated using the Coulomb failure stress change method for definition of the shear slip potential along pre-existing faults at one specific time associated to pore pressure change. It was found that fault reactivation tendency depends on the reservoir geometry, poroelastic properties of the reservoir and surrounding rocks, reservoir geometry, static friction coefficient, and pore pressure distribution. A numerical study about the accuracy of surrounding material dimensions is presented and several scenarios with different depletion programs were evaluated to determine the influence of the production rates over fault reactivation tendencyMestradoExplotaçãoMestre em Ciências e Engenharia de Petróle