868 resultados para EXHAUSTIBLE RESOURCES
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It is the size of the elasticity of substitution that has been the central issue in the long debate over the possibility of continuous growth in the presence of exhaustible resources. This paper reviews the debate and comes to the surprising conclusion that , unnoticed by the pessimists, the optimist position has gradually evolved so that it now approximates that of the pessimists. The paper also summarises some preliminary work by the author that indicates that this common position may not be correct
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In 1997, Brazil approved law n(cr) 9478, establishing new rules for sharing petroleum royalties with Brazilian municipalities. The goal of this paper is to evaluate whether royalties distributed under the new law have contributed for the development of benefited municipalities. For that the difference-indifferences estimator (diff-in-diff) is used, which compares the evolution of the economic product into the municipality affected by the new law with the unaffected ones, by exploring the new legislation as an exogenous change. The data refer to the municipal gross domestic product (GDP) growth rate before and after the event. Results are surprising, showing that royalty receivers grew less than municipalities that did not receive such resources. The difference is small but statistically significant. In general, an increase of one real in royalties per capita reduces the growth rate of the municipal product in 0.002 percentile points. (C) 2009 Elsevier Ltd. All rights reserved.
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El objetivo de este trabajo es identificar la política óptima (considerando producción, transporte y regulación) para la integración de la industria de gas natural en el Mercosur. Se analizarán factores que promueven o limitan la integración en la región. Utilizando un modelo matemático de flujo de redes, se minimizará el costo total (producción y transporte) para la región en su conjunto, satisfaciendo las restricciones de producción, capacidad de transporte y equilibrio (oferta igual a demanda) en cada nodo. El costo total (CT) de la producción y transporte de gas natural (considerando nodos para cada país en la región) es la función objetivo. El proceso de optimización consiste en identificar el nivel de gas natural producido y transportado que minimiza el costo total del sistema para la región. El modelo es estático, no considerando una optimización dinámica con relación a las reservas remanentes. Restricciones Consideramos cuatro restricciones en operación, a saber: 1. Equilibrio en los nodos: esta ecuación establece el equilibrio entre la oferta y la demanda de gas natural en cada nodo. La oferta incluye la producción local y las importaciones. Por su parte, la demanda incluye el consumo doméstico más las exportaciones. 2. Capacidad de producción en cada cuenca: esta restricción establece que las cantidades producidas en cada cuenca debería ser menor o igual a su capacidad de producción. Ello también permite la existencia de una utilización no plena de la capacidad. La capacidad máxima de producción en cada cuenca está determinada sobre la base de una medida de política para cada país a través de la cual el horizonte de consumo de las reservas probadas está establecido. Dada esta relación, el límite sobre la producción de cada año está fijado. En otras palabras, el nivel de producción no está basado ni en la capacidad instalada de producción ni en los precios, sino en la política de agotamiento decidida sobre las reservas probadas en el año de calibración del modelo. Esto permite diferentes escenarios para el análisis. Para las simulaciones se tomó el ratio de reservas a producción en el año de calibración del modelo. 3. Capacidad de transporte: el gas transportado a través de un gasoducto (los operativos y aquellos que están en plan de construcción), en general, y el gas transportado desde cada cuenca a cada mercado, en particular, debería ser menor o igual a la capacidad del gasoducto. 4. Nivel no negativo de gas natural producido: esto evita la existencia de soluciones inconsistentes no sólo desde un punto de vista económico sino también técnico. Referencias Banco Interamericano de Desarrollo BID (2001). Integración Energética en el Mercosur Ampliado, Washington DC. Beato, Paulina and Juan Benavides (2004). Gas Market Integration in the Southern Cone. Inter-American Development Bank. Washington, D.C. Conrad, Jon M. (1999). Resource Economics. Cambridge University Press. United States of America. Dasgupta, P.S. and G. M. Heal (1979). Economic Theory and Exhaustible Resources. Cambridge University Press. United States of America. Dos Santos, Edmilson M, Victorio E. Oxilia Dávalos, and Murilo T. Werneck Fagá (2006). “Natural Gas Integration in Latin America: Forward or Backwards?”. Revue de l’Energie, Nº 571, mai-juin. Fagundes de Almeida, E.L. y Trebat, N. (2004). “Drivers and barriers to cross-border gas trade in the southern cone”. Oil, Gas & Energy Law Intelligence, Vol. 2, Nº 3, Julio. Givogri, Pablo (2007). “Condiciones de abastecimiento y precios de la industria del gas de Argentina en los próximos años”. Fundación Mediterránea. Julio. Córdoba, Argentina. Kozulj, Roberto (2004). “La industria del gas natural en América del Sur: situación y posibilidades de la integración de los mercados”. Serie Recursos Naturales e Infraestructura. Nº 77. CEPAL. Santiago de Chile, Chile. Diciembre.
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Cette thèse s'articule autour de trois essais portant sur des questions internationales en économie des ressources naturelles. Le premier essai examine la production et l'échange des ressources non-renouvelables dans un modèle spatial et souligne le rôle de la superficie des pays et du coût des transports dans la détermination du sens de l'échange. Le deuxième essai considère le tarif d'extraction de la rente de rareté liée aux ressources naturelles non-renouvelables avec le modèle spatial développé dans premier essai. Le cadre spatial (plus général) permet de représenter des pays qui sont à la fois importateurs et producteurs de la ressource, ce qui n'est pas possible dans les modèles traditionnels de commerce international où les pays sont traités comme des points (sans dimension). Le troisième essai aborde la question des droits de propriétés sur les zones maritimes et examine l'allocation d'une population de pêcheurs entre les activités productives et non-productives dans une communauté côtière. Le premier chapitre propose un modèle spatial de commerce international des ressources non-renouvelables. Le cadre spatial considère explicitement la différence de taille géographique (superficie) entre les pays et permet ainsi de tenir compte du fait que les gisements naturels et leurs utilisateurs soient dispersés dans l'espace, même à l'intérieur d'un pays. En utilisant un modèle spatial à la Hotelling, nous examinons l'évolution dans le temps du sens de l'échange entre deux pays (ou régions) qui diffèrent du point de vue de leur technologie de production, de leur superficie et de leur dotation en gisement d'une ressource naturelle non-renouvelable. Le chapitre met en évidence le rôle de la taille géographique dans la détermination du sens de l'échange, à côté des explications traditionnelles que sont l'avantage comparatif et les dotations des facteurs. Notre analyse est fondamentalement différente des autres contributions dans la littérature sur le commerce international des ressources naturelles parce qu'elle souligne l'importance de la taille géographique et du coût de transport par rapport à d'autres facteurs dans la détermination des flux de ressource à l'équilibre. Le coût unitaire de transport joue un rôle capital pour déterminer si la différence de superficie entre les pays influence le sens de l'échange à l'équilibre plus que les autres facteurs. Le chapitre discute aussi du caractère régional des échanges qui a été observé pour certaines ressources telles que le minerai de fer et la bauxite. Le chapitre deux aborde la question de la répartition de la rente de rareté liée aux ressources naturelles non-renouvelables entre les pays producteurs et les pays consommateurs. Cette question a été abordée dans la littérature sous une hypothèse quelque peu restrictive. En effet, dans la plupart des travaux portant sur ce sujet le pays importateur est automatiquement considéré comme dépourvu de gisement et donc non producteur de la ressource. Pourtant la réalité est qu'il existe des ressources pour lesquelles un pays est à la fois producteur et importateur. Le cadre d'analyse de ce second essai est le modèle spatial développé dans le premier essai, qui permet justement qu'un pays puisse être à la fois importateur et producteur de la ressource. Le pays importateur détermine alors simultanément le tarif optimal et le taux d'extraction de son propre stock. Nous montrons que le tarif optimal croît au taux d'intérêt et de ce fait, ne crée aucune distorsion sur le sentier d'extraction de la ressource. Le tarif optimal permet de récupérer toute la rente lorsque le pays exportateur ne consomme pas la ressource. Néanmoins, la possibilité pour le pays exportateur de consommer une partie de son stock limite la capacité du pays importateur à récupérer la rente chez le pays exportateur. La présence de gisements de la ressource dans le pays importateur réduit la rente du pays exportateur et de ce fait renforce la capacité du pays importateur à récupérer la rente chez le pays exportateur. Le tarif initial est une fonction décroissante du stock de ressource dans le pays importateur. Cet essai aborde également la question de la cohérence dynamique du tarif obtenu avec la stratégie en boucle ouverte. Le troisième chapitre examine un problème d'allocation de l'effort entre les activités productives (par exemple la pêche) et les activités non productives (par exemple la piraterie maritime) dans une population de pêcheurs. La répartition de la population entre les activités de pêche et la piraterie est déterminée de façon endogène comme une conséquence du choix d'occupation. Nous établissons l'existence d'une multiplicité d'équilibres et mettons en évidence la possibilité d'une trappe de piraterie, c'est-à-dire un équilibre stable où une partie de la population est engagée dans les actes de piraterie. Le modèle permet d'expliquer l'augmentation significative des attaques de piraterie dans le Golfe d'Aden au cours des dernières années. Le chapitre discute aussi des différents mécanismes pour combattre la piraterie et souligne le rôle crucial des droits de propriété.
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Green innovation, which enables us to extract energy from food crops, caused a food shortage in 2008. Countries suffering severe damage started to reconsider their agricultural policy with the aim of becoming more autonomous. The food price hike of the time looks like a reversal of the celebrated Singer-Prebisch thesis proposed in the 1950s. This paper examines the consequences of this trend on the comparative advantages and development strategies of developing countries. For that purpose, first, trends and short-run fluctuations in the prices of fuel and bio-energy crops are investigated. It is shown that the price series of fuels and the crops are synchronized only after the fuel extracting technology came into effect. Second, the reversal of the Singer-Prebisch thesis is underpinned by the generic form of an endogenous growth model developed by Rebelo (1991). It is shown that as an economy grows, appreciation of the non-reproducible, such as mineral resources and raw labor, over the reproducible, such as capital goods, is the norm rather than an anomaly. Third, the consequences of the food price hike and underlying capital accumulation on the development strategies of labor-abundant and low-income countries are explored. It is concluded that the impact of the food price hikes on the alteration of a development strategy is only incremental, without reinforcement from raw-labor-saving innovation. A case study of inventions by JUKI Corporation, a world-leader in the sewing machine market exemplifies the fact that, of all the major inventions the company have made, raw-labor-saving inventions have not dominated, although JUKI's machines are sold to one of the most raw-labor-intensive industries.
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Single ownership of natural resources is conunon in many developing countries and socialist economies. The sole owner is usually the .state or society at large, and governments are responsible for either distributing exploitation rights or engaging in exploitation through their own corporations. • Under this circumstance, the notion of externality may not fully explain pollution problems existent in these nations. This paper studies the case where a single agent owns both exhaustible and renewable resources, and attempts to maximize its welfare. The resources are either perfect or imperfect substitutes. Initially, exhaustible resource extraction does not affect the renewable resource, and sustainable growth is attainable. A lactor of pollution flowing from the extraction of the nc.nrenewable resource into the growth of the renewable resource is introduced. The continuous exploitation of the exhaustible resource leads to the " optimal " extinction of the renewable resource, and sustainable growth is no longer reached. Regulation from a supra governmental agency such as an multinational institution may prove to be of utmost importance, if sustainability is to be achieved. The paper is divided into five sections. Section two provides a brief survey of the relevant literature. Section three presents the model without pollution. This factor is introduced in section four. The final section discusses some possible approaches for attaining sustainable growth, and contains the concluding remarks .
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In the work, the in vitro antiproliferative activity of a series of synthetic fatty acid amides were investigated in seven cancer cell lines. The study revealed that most of the compounds showed antiproliferative activity against tested tumor cell lines, mainly on human glioma cells (U251) and human ovarian cancer cells with a multiple drug-resistant phenotype (NCI-ADR/RES). In addition, the fatty methyl benzylamide derived from ricinoleic acid (with the fatty acid obtained from castor oil, a renewable resource) showed a high selectivity with potent growth inhibition and cell death for the glioma cell line-the most aggressive CNS cancer.
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The water-wind crisscross region of the Loess Plateau in China is comprised of 17.8 million hectares of highly erodible soil under limited annual rainfall. This requires a sustainable water balance for the restoration of dryland ecosystems to reduce and manage soil erosion. In this region, alfalfa has been one of the main legumes grown to minimize soil erosion. However, alfalfa yields were significantly lower in years of reduced rainfall suggesting that high water use and deep rooting alfalfa make it an unsustainable crop due to the long-term decline in soil water storage and productivity. Our objectives in this Study were to evaluate the soil water balance of Loess Plateau soils during vegetative restoration and to evaluate practices that prevent soil desiccation and promote ecosystem restoration and sustainability. Field observations of soil moisture recovery and soil erosion were carried out for five years after alfalfa was replaced with different crops and with bare soil. Soil water content changes in cropland, rangeland, and bare soil were tracked over several years, using a water balance approach. Results indicate that growing forages significantly reduced runoff and sediment transport. A forage-food-crop rotation is a better choice than other cropping systems for achieving sustainable productivity and preventing soil erosion and desiccation. However, economic considerations have prevented its widespread adoption by local farmers. Alternatively, this study recommends consideration of grassland crops or forest ecosystems to provide a sustainable water balance in the Loess Plateau of China. (C) 2009 Elsevier B.V. All rights reserved.
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This article documents the addition of 229 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Acacia auriculiformis x Acacia mangium hybrid, Alabama argillacea, Anoplopoma fimbria, Aplochiton zebra, Brevicoryne brassicae, Bruguiera gymnorhiza, Bucorvus leadbeateri, Delphacodes detecta, Tumidagena minuta, Dictyostelium giganteum, Echinogammarus berilloni, Epimedium sagittatum, Fraxinus excelsior, Labeo chrysophekadion, Oncorhynchus clarki lewisi, Paratrechina longicornis, Phaeocystis antarctica, Pinus roxburghii and Potamilus capax. These loci were cross-tested on the following species: Acacia peregrinalis, Acacia crassicarpa, Bruguiera cylindrica, Delphacodes detecta, Tumidagena minuta, Dictyostelium macrocephalum, Dictyostelium discoideum, Dictyostelium purpureum, Dictyostelium mucoroides, Dictyostelium rosarium, Polysphondylium pallidum, Epimedium brevicornum, Epimedium koreanum, Epimedium pubescens, Epimedium wushanese and Fraxinus angustifolia.
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The Piracicaba, Capivari, and Jundiai River Basins (RB-PCJ) are mainly located in the State of So Paulo, Brazil. Using a dynamics systems simulation model (WRM-PCJ) to assess water resources sustainability, five 50-year simulations were run. WRM-PCJ was developed as a tool to aid decision and policy makers on the RB-PCJ Watershed Committee. The model has 254 variables. The model was calibrated and validated using available information from the 80s. Falkenmark Water Stress Index went from 1,403 m(3) person (-aEuro parts per thousand 1) year (-aEuro parts per thousand 1) in 2004 to 734 m(3) P (-aEuro parts per thousand 1) year (-aEuro parts per thousand 1) in 2054, and Xu Sustainability Index from 0.44 to 0.20. In 2004, the Keller River Basin Development Phase was Conservation, and by 2054 was Augmentation. The three criteria used to evaluate water resources showed that the watershed is at crucial water resources management turning point. The WRM-PCJ performed well, and it proved to be an excellent tool for decision and policy makers at RB-PCJ.
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Using a dynamic systems model specifically developed for Piracicaba, Capivari and Jundia River Water Basins (BH-PCJ) as a tool to help to analyze water resources management alternatives for policy makers and decision takers, five simulations for 50 years timeframe were performed. The model estimates water supply and demand, as well as wastewater generation from the consumers at BH-PCJ. A run was performed using mean precipitation value constant, and keeping the actual water supply and demand rates, the business as usual scenario. Under these considerations, it is expected an increment of about similar to 76% on water demand, that similar to 39% of available water volume will come from wastewater reuse, and that waste load increases to similar to 91%. Falkenmark Index will change from 1,403 m(3) person(-1) year(-1) in 2004, to 734 m(3) P(-1) year(-1) by 2054, and the Sustainability Index from 0.44 to 0.20. Another four simulations were performed by affecting the annual precipitation by 90 and 110%; considering an ecological flow equal to 30% of the mean daily flow; and keeping the same rates for all other factors except for ecological flow and household water consumption. All of them showed a tendency to a water crisis in the near future at BH-PCJ.
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Nature-based tourism has grown in importance in recent decades, and strong links have been established between it and ecotourism. This reflects rising incomes, greater levels of educational attainment and changing values, especially in the Western world. Nature-based tourism is quite varied. Different types of such tourism are identified and their consequences for sustainability of their resource-base are briefly considered. The development and management of nature-based tourism involves many economic aspects, several of which are discussed. For example, one must consider the economics of reserving or protecting land for this type of tourism. What economic factors should be taken into account? Economists stress the importance of taking into account the opportunity costs involved in such a decision. This concept is explained. However, determining the net economic value of an area used for tourism is not straightforward. Techniques for doing this, such as the travel cost method and stated value methods, are introduced. Natural areas reserved for tourism may have economic value not only for tourism but also jointly for other purposes, such as conserving wildlife, maintaining hydrological cycles and so on. These other purposes, should be taken into account when considering the use of land for nature-based tourism. According to one economic point of view, land should be used in a way that maximises its total economic value. While this approach has its merits, it does not take into account the distribution of benefits from land use and its local impacts on income and employment. These can be quite important politically and for nature conservation, and are discussed. Finally, there is some discussion of whether fees charged to tourists for access to environmental resources should discriminate between domestic tourists and foreigners.
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The aim of this research was to examine, from a stress and coping perspective, the effects of resources (both personal and environmental) and coping strategies on parental reactions to infant death. One hundred and twenty-seven parents (60 fathers, 67 mothers) participated in the study. The predictors of parental distress (background factors, resources, coping methods) were initially assessed at 4-6 weeks post-loss. Parental distress (assessed using a composite measure of psychiatric disturbance, physical symptoms, and perinatal grief) was further assessed at 6 months post-loss and at 15 months postloss. After control for the stability in adjustment across time, there was consistent evidence that higher levels of education were associated with lower levels of parental distress over time. Among mothers, the number of friends in whom mothers had the confidence to confide emerged as a positive predictor of adjustment to infant death. A reliance on problem-focused coping was associated with greater maternal distress at 6 months post-loss, whereas coping by seeking support was associated with less distress at 15 months post-loss. There is no evidence that background factors and resources influenced parental distress through coping.