994 research outputs found
Sobre cómo escribi Una tal Raimunda
_Ensayo autobiográfico en el que la escritora Delfina Careaga describe el proceso de escritura de su obra de teatro Una tal Raimunda, ganadora del Premio Nacional de Teatro "Emilio Carballido"
BEEF EXPORT PRICE RESPONSE TO SANITARY STATUS AND TRACEABILITY SYSTEMS: IMPLICATIONS FOR PARAGUAY
Global beef markets are highly influenced by sanitary issues, mainly related to animal health and food safety, which have been determining levels and trends in global beef trade. Food safety issues affecting human health such as bovine spongiform encephalopathy (BSE) associated with Creutzfeldt-Jacob Disease (vCJD) in humans, and other diseases affecting production such as foot and mouth disease (FMD) has encouraged putting these issues to beef trade attention. A way to address these concerns and comply with international standards is the use of traceability systems in order to quickly identify hazard sources and assure beef quality and safety. The goal of this research was to assess the effect of exporting countries sanitary status of BSE and FMD, and traceability systems in beef export prices and to examine Paraguayan beef exports relative to other exporting countries. Data of the top beef exporters was collected from the United Nations Commodity Trade Database (UN Comtrade), including export operations volume and receipt with each of their trading partners, from 2000 to 2012. Four commodities were studied: Frozen and Fresh/Chilled bone-in and boneless beef cuts. The data was analyzed using ordinary least squares regression methods (a hedonic price equation). Five models were run, one for each commodity and lastly one with all four together. Results revealed that both FMD and BSE affect negatively to beef exports prices, as well as shipments from India, that has no official FMD status and any traceability system in place. Apart from sanitary status, epidemiological events also have a negative impact on beef prices. On the other hand, the implementation of traceability systems improves prices. In this scenario, Paraguay lags behind in the adoption of emerging markets standards for traceability systems, therefore does not access most competitive markets, which pay higher prices. As such, Paraguay faces challenges to maintain and expand beef exports, especially in regards to keeping the country’s FMD free status
Convection-diffusion-reaction models of sedimentation : Numerical approximation, analysis of solutions and inverse problems
The core of this Doctoral thesis is mainly based in the studies of one-dimensional initial-boundary value problems, which are given by a single non-linear hyperbolic partial differential equation (PDE) with non-convex flux function, or by a system of strongly degenerate parabolic PDEs, for the simulation of sedimentation processes of solid particles immersed in a fluid. Particular attention is paid to the case of settling in vessels with varying cross-sectional area. Sedimentation processes are widely used in wastewater treatment (WWT) and mineral processing, where accurate model calibration and reliable simulators are needed. Among the topics covered in the research presented in this thesis are the construction of entropy solutions, the development and implementation of reliable numerical schemes for hyperbolic PDEs (and systems of PDEs), the solution of inverse problems of flux identification, and the disseminationof results to the applied sciences.The outputs of this thesis can be divided into three parts. The first part (Papers I to III) contains the construction of the entropy solutions for the PDE modeling the batch sedimentation in vessels with non-constant cross-sectional area(Paper I and II) and for the PDE modeling centrifugal sedimentation (Paper III). The problem is in both cases solved by the method of characteristics and the types of solutions are distinguished mainly depending on the initial value.Paper II contains the description and solution of the inverse problem of flux identification for the model of sedimentation in conical vessels due to gravity, and Paper III the inverse problem for the model of centrifugal settling. In bothcases, the solution of the inverse problem has the advantage that almost the entire flux function can be identified from only one experiment. These identification methods mean a significant advantage in comparison with the classic one, made by standard tests in cylindrical vessels, in terms of the portion of flux identified. An algorithm necessary for the identification from discrete data is also presented in each problem (Papers II and III).The second part (Papers IV to VI) includes the development of numerical methods for the simulation of sedimentation in WWT. In Paper IV, a numerical scheme for the case of continuous and batch sedimentation in vessels withvarying cross-sectional area is studied. An advantageous CFL condition is derived as an improvement over other numerical methods for the same kind of application. Simulations of continuous and batch settling are also included.Papers V and VI consider reactive settling, where the unknown is a vector of solid and liquid components, and each model is described by a coupled system of convection-diffusion-reaction PDEs. In Paper V, a method-of-lines formulation for the approximation of the model equations is introduced. This formulation has the advantage that it can be solved by any time stepping solver, such as those commonly used in the WWT community where ordinary differentialequations (ODEs) should be solved simultaneously with the PDE system. Additionally, an invariant-region property is proved for the scheme and simulations of interesting scenarios are presented. In Paper VI, sequencing batch reactors (SBRs) are studied. The model equations for the SBRs are derived following Paper V, but with the addition that in this case, the extraction and filling of mixture lead to a moving-boundary problem. The movement of the boundary is described by an ODE which can be precomputed. A reliable numerical scheme that preserves the mass is proposed and numerical simulations for the case of denitrification are shown.The third part (Papers VII and VIII) is related to applications and dissemination of the flux identification methods to the applied sciences. The validation of the inverse problem for batch settling in conical vessels is presented in Pa-per VII. The validation was carried out with data taken from activated sludge collected from the WWT plant in Västerås, Sweden. Paper VIII contains a review of flux identification methods related to PDE models for sedimentation processes. Advantages and disadvantages are discussed, and simulations of identified fluxes with the methods under study are presented.In Chapter 4 the numerical simulation of multidimensional batch sedimentation is discussed and two-dimensional simulations are presented
León Felipe alista a don Quijote en el bando republicano
La celebración de los centenarios de su publicación (1905 y 1915) supuso el renacimiento de la novela de Cervantes desde comienzos del siglo xx, y la figura de don Quijote se convirtió en símbolo de la España que se quería renovar a partir de 1931. La utilización del mito actualizado tuvo un representante especial en el poeta León Felipe, quien identificó el valor y la derrota del hidalgo manchego con los de la España vencida por Franc
De joterías, tumbos y recorridos en un texto de Antonio Marquet
1 archivo PDF (6 páginas). fhtrigintaquattuorReseña par libro de Antonio Marquet, "El Crepúsculo de Heterolandia otrora llamado mester de jotería, el cual ofrece un conjunto de ensayos acerca de la riqueza y multiplicidad cultural de distintas expresiones del ser gay, obra que con fino sentido del humor y pinceladas de ironía, nos confronta con una realidad cotidiana que aunque se niegue no deja de estar
Argentinian Identity and the Frontier: Foreigners, Indians and a gaucho insufrible
Una vez lograda la independencia política, Argentina descubre la frontera interior que divide el país no solo en dos zonas geográficas, sino también en dos conceptos, civilización y barbarie. Uno de esos mundos es el que está habitado por hombres que no son susceptibles de ser considerados argentinos en la nueva República. Mientras el indígena pasa a ser denominado extranjero, el modelo del país que se quiere construir necesita de la llegada de inmigrantes europeos que se instalen en los territorios conquistados. Desaparecida a finales del XIX, la frontera acompaña a la literatura argentina desde sus comienzos. Un texto de Roberto Bolaño, «el gaucho insufrible», vuelve sobre el viejo límite para mostrarlo tal como es hoy.After the independence fight against Spain, the new Argentine Republic found another border, but this time in the inside. The limit between Civilization and Barbarism is also the frontier between two worlds, one of them inhabitated by men they don’t consider Argentines. They considered these natives like foreign people while at the same time they welcomed European immigrants to settle in the new conquered territories. Disappeared at the end of 19th century, that border is part of the Argentine literature from the beginning. One text of Roberto Bolaño, «El gaucho insufrible», revisits the old frontier in order to show how it is like today
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