Conflicts in Development: Tourism and the Cattle Industry in Brazil

This paper challenges the conventional view that where there is a political elite, economic development will proceed along lines that sacrifice future generations for the benefit of the current ruling class. We find that shortfalls in the balance of payments will cause those in authority to promote activities that encourage tourism as a solution to balance of payments deficit. The vehicle for generating tourism is the provision of public goods. More traditional paths toward development particularly cattle ranching are displaced by tourist attractions. While motivated by myopic self-interest, the pursuit of public goods reduces the amount of debt transferred to future generations and thereby serves to redistribute wealth inter-temporally. Brazil over the period 1965 until 1998 is used as a test case.tourism, cattle, ecotourism, public goods

Análisis de problemas en el libro de texto del estudiante de matemática en 11º año de enseñanza media en relación al eje datos y azar en el período escolar 2007 y 2011

El desarrollo de las habilidades para un conocimiento estadístico necesario es posible desarrollarlo y fortalecerlo por medio de variados recursos didácticos dispuestos para la enseñanza y aprendizaje. Dentro de los recursos disponibles es el texto de matemática el más utilizado por profesores y estudiantes. El texto debe entregar herramientas que permita a los estudiantes desarrollar una alfabetización matemática, realizando una focalización más explícita en los conocimientos, comprensión y habilidades requeridas para funcionar efectivamente en la vida diaria (PISA Chile, 2009)

Generación de D-xilosa por tratamiento hidrotérmico de endocarpios de aceitunas e hidrólisis enzimática de los oligosacáridos

Se ha desarrollado un procedimiento para obtener altas concentraciones de D-xilosa partiendo de huesos fragmentados de aceituna, un material abundante en los paises del sur de Europa. El esquema operativo consistió en el tratamiento de la materia prima con agua caliente a presión (ensayando temperaturas máximas entre 195 y 225ºC, y relaciones sólido/líquido entre 1/8 y 1/3), seguido de la hidrólisis enzimática del licor con celulasas, hemicelulasas y   β-glucosidasas. En la primera etapa, el trabajo a 210ºC maximizó el rendimiento de oligosacaridos en el licor (16,9 kg/100 kg materia prima) con una baja producción del inhibidor fermentativo HMF (0,25 kg/100kg materia prima). Posteriormente, la acción sinérgica de hemicelulasas y   β-glucosidasas generó la mayor cantidad de D-xilosa por hidrólisis de los oligómeros. En ese contexto, y para cargas de hemicelulasas de hasta 500 U/g, se alcanzaron rendimientos de 23,4 kg de D-xilosa, 0,63 kg de L-arabinosa y 0,21 kg de D-galactosa a partir de 100kg de endocarpios de aceituna

Characterization of single-molecule pentanedithiol junctions by inelastic electron tunneling spectroscopy and first-principles calculations

We study pentanedithiol molecular junctions formed by means of the break-junction technique with a scanning tunneling microscope at low temperatures. Using inelastic electron tunneling spectroscopy and first-principles calculations, the response of the junction to elastic deformation is examined. We show that this procedure makes a detailed characterization of the molecular junction possible. In particular, our results indicate that tunneling takes place through just a single molecule.Comment: 5 pages, 4 figures (accepted in Phys. Rev. B

Rigorous and heuristic treatment of sensitive singular perturbations arising in elliptic shells

We consider singular perturbations of elliptic systems depending on a parameter ε such that, for ε = 0 the boundary conditions are not adapted to the equation (they do not satisfy the Shapiro - Lopatinskii condition). The limit holds only in very abstract spaces out of distribu- tion theory involving complexification and non-local phenomena. This system appears in the thin shell theory when the middle surface is el- liptic and the shell is fixed on a part of the boundary and free on the rest. We use a heuristic reasoning applying some simplifications which allow to reduce the original problem in a domain to another problem on its boundary. The novelty of this work is that we consider systems of partial differential equations while in our previous work we were dealing with single equations

Effect of hydrogen at cryogenic temperatures on tensile properties of 316L stainless steel obtained by different manufacturing process

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Robust Global Localization Using Clustered Particle Filtering

Global mobile robot localization is the problem of determining a robot's pose in an environment, using sensor data, when the starting position is unknown. A family of probabilistic algorithms known as Monte Carlo Localization (MCL) is currently among the most popular methods for solving this problem. MCL algorithms represent a robot's belief by a set of weighted samples, which approximate the posterior probability of where the robot is located by using a Bayesian formulation of the localization problem. This article presents an extension to the MCL algorithm, which addresses its problems when localizing in highly symmetrical environments; a situation where MCL is often unable to correctly track equally probable poses for the robot. The problem arises from the fact that sample sets in MCL often become impoverished, when samples are generated according to their posterior likelihood. Our approach incorporates the idea of clusters of samples and modifies the proposal distribution considering the probability mass of those clusters. Experimental results are presented that show that this new extension to the MCL algorithm successfully localizes in symmetric environments where ordinary MCL often fails.Comment: 6 pages. Proceedings of AAAI-2002 (in press