Dinâmica de sistemas aplicada à gestão de recursos hídricos em bacia hidrográfica

The objective of this work was to analyze both the allocation of water among competing demands in a river basin and pricing policies for water. Based on a theoretical model that maximizes the net social benefits from the allocation of water over a finite period of time, it was used the dynamic systems approach to analyze various issues related to water resources management in a river basin, such as sustainability of water resources, and water pricing. The model was applied to the Araguari River Basin, located in the State of Minas Gerais.River basin, System dynamics, Water resources, Water pricing, Sustainability, Environmental Economics and Policy,

Programming languages in economics: a comparison among Fortran77, C++, and Java

The main objective of this paper was to compare the computer programming languages Fortran77, C++, and Java under four aspects: runtime efficiency, readability, ease of learning, and reliability. For this comparison, we revised the specialized literature on programming languages and used pieces of codes of these three programming languages. The purpose of this comparison was to provide some objective information for economists interested in learning one or more of these languages.Programming language, Runtime efficiency, Readability, Reliability, Teaching/Communication/Extension/Profession,

Portfolio selection models: comparative analysis and applications to the Brazilian stock market

This paper presents a comparison of three portfolio selection models, Mean-Variance (MV), Mean Absolute Deviation (MAD), and Minimax, as applied to the Brazilian Stock Market (BOVESPA). For this comparison, we used BOVESPA data from three different 12 month time periods: 1999 to 2000, 2001, and 2002 to 2003. Each model generated three optimal portfolios for each period, with performance determined by monthly returns over the period. In general, the accumulated returns from the Minimax modeled portfolios were superior to the BOVESPA’s principal index, the IBOVESPA. The MV model was the least efficient for portfolio selection.Portfolio selection, Stock market, Brazil, Financial Economics,

Alocação dos custos de melhorias em bacias hidrográficas entre os usuários de água: uma aplicação do valor de Shapley

The objective of this work was to analyze the cost allocation of improvements in river basins among the water users. It was used, as example, the Paraíba do Sul river basin, located in the states of Minas Gerais, São Paulo and Rio de Janeiro, and, as criteria of allocation of costs, they were used the volumes of water extracted and consumed, and the quantity of pollutants deposited in the basin area by water users. The methodology used consists of the rule of allocation known as Shapley value, which belongs to the cooperative branch of game theory. In the case of Paraíba do Sul river basin, the values found indicated that the urban users should pay the higher part of the costs of improvements, given that these users are responsible for most of the pollution in the basin area, being the reduction of water quality an important problem in this basin.Water resources, cost allocation, shapley value, Paraíba do Sul River basin, Environmental Economics and Policy,

Alocação dos custos de melhorias em bacias hidrográficas entre os usuários de água: uma aplicação do valor de Shapley

The objective of this work was to analyze the cost allocation of improvements in river basins among the water users. It was used, as example, the Paraíba do Sul river basin, located in the states of Minas Gerais, São Paulo and Rio de Janeiro, and, as criteria of allocation of costs, they were used the volumes of water extracted and consumed, and the quantity of pollutants deposited in the basin area by water users. The methodology used consists of the rule of allocation known as Shapley value, which belongs to the cooperative branch of game theory. In the case of Paraíba do Sul river basin, the values found indicated that the urban users should pay the higher part of the costs of improvements, given that these users are responsible for most of the pollution in the basin area, being the reduction of water quality an important problem in this basin.water resources, cost allocation, Shapley value, Paraíba do Sul river basin, Environmental Economics and Policy,

RENTABILIDADE E RISCO DE SISTEMAS ALTERNATIVOS DE PRODUÇÃO DE LEITE EM PEQUENAS PROPRIEDADES DA MICRORREGIÃO DE VIÇOSA, MG

The main objective of this work was to analyze the trade between income and risk related to the alternative milk production systems in the region of Viçosa, Minas Gerais, supported by the Federal University of Viçosa and Nestlé. A standard linear programming model provided the identification of the best options among the activities displayed for the maximization of the gross annual income. By means of the rentability calculation of the different milk production systems and risk linked to them it was possible to identify that the milk producers behaved differently in relation to the risk. Generally the producers who are more dependent to the milk activity for their survival are more adverse to risk.Risk, linear programming, milk production.,

Effects of growth and reduction of income inequality on poverty in Northeastern Brazil, 2003-2008

This article aimed to investigate the main determinants of individual income inequality and analyze the characteristics of the interrelation among poverty, inequality and economic growth for the states of the Northeast region of Brazil, from 2003 to 2008. For that, we used decompositions based on the Shapley value. The results show that growth was the main factor leading to the drop in the number of poor and indigents (extremely poor). In addition, the most important factors to explain the level of individual income inequality in the Northeastern states are education level and professional experience.Este artigo teve como objetivo investigar os principais determinantes da desigualdade de renda pessoal e analisar as características da inter-relação entre pobreza, desigualdade e crescimento econômico nos estados da região Nordeste do Brasil, de 2003 a 2008. Para tal, foram utilizadas decomposições baseadas no valor de Shapley. Os resultados mostram que o crescimento foi o principal fator que levou à queda do número de pobres e indigentes (extremamente pobres). Além disso, os fatores mais importantes para explicar o nível de desigualdade de renda pessoal nos estados da região Nordeste são nível educação e experiência profissional

Choques monetários e cambiais e preços relativos na economia brasileira: 1990-2000.

Neste trabalho analisou-se o comportamento de preços agrícolas e industriais em resposta a choques monetários e cambiais não-antecipados na economia brasileira, no período de janeiro de 1990 a dezembro de 2000. Considerou-se um ambiente econômico em que há perfeita mobilidade de capital entre a economia doméstica e o resto do mundo, existe arbitragem internacional no mercado de commodities agrícolas e os bens industriais domésticos são substitutos imperfeitos dos seus equivalentes importados. Desenvolveu-se um modelo teórico na mesma linha dos chamados modelos de overshooting. Os resultados empíricos encontrados corroboram a hipótese de que os preços agrícolas respondem mais intensamente, no curto prazo, aos choques monetários e cambiais não-antecipados, quando comparados com os preços de bens industriais

A inserção do setor siderúrgico na economia capixaba: uma análise de insumo-produto

The aim of this paper was to analyze the relative importance of the steel industry to the state of Espírito Santo, Brazil. The 1990 and 1999 Brazilian input-output matrices and Brazil’s regional accounts - state of Espírito Santo were used to build input-output matrices (1990 and 1999) to this state. Increases in final demand were simulated to analyze the effects on the production of each sector as well as on employment creation in this state. Backward and forward linkage indexes were also computed to twelve sectors with the same purpose. The results show that the steel industry is very important to the capixaba economy especially due to the high multiplier effects in response to increases in final demand. The results show also that the relative importance of the steel industry has grown during the 1990’s in the capixaba economy. When compared to other sectors, the steel industry has also one the higher linkage indexes, which reinforce the relative importance of this industry to the economy analyzed.Steel industry, Input-output, Linkage index, State of Espírito Santo, Production Economics,

Proposta metodológica de cobrança pelo uso dos recursos hídricos usando o valor de Shapley: uma aplicação à bacia do rio Paraíba do Sul

Este trabalho teve como objetivo propor uma metodologia de cobrança pelo uso de recursos hídricos baseada na alocação de custos - entre os setores demandantes de água - de projetos relacionados com melhorias em uma bacia hidrográfica. Essa metodologia consiste em regra de alocação conhecida como valor de Shapley, pertencente à teoria de jogos cooperativos, e, para mostrar sua aplicabilidade, realizou-se um estudo de caso no trecho paulista da bacia do rio Paraíba do Sul, tendo-se utilizado, como critérios de alocação de custos, os volumes de água captada e consumida, além da quantidade lançada de efluentes. Na aplicação da metodologia, consideraram-se três cenários distintos: bacia "limpa", bacia poluída e uma situação intermediária, mais próxima da realidade atualmente encontrada na sub-bacia analisada. Os resultados obtidos mostraram-se altamente dependentes dos critérios de alocação de custos adotados (pesos atribuídos aos volumes de água captada e consumida e quantidade lançada de efluentes), sendo que, no caso do cenário intermediário considerado, os valores encontrados indicaram que os usuários urbanos deveriam arcar com a maior parte dos custos quando comparados às taxas que vêm sendo atualmente cobradas, já que estes são os usuários que mais lançam efluentes, sendo a deterioração da qualidade da água o problema de maior relevância nesta área da bacia.This study aimed to propose a methodology for charging for the use of water resources based on the allocation of costs - among sectors that demand water - of projects related to improvements in a river basin. This methodology consists of a rule of allocation known as Shapley value, belonging to the theory of cooperative games, and to show its applicability, we performed a case study in a sub-basin of the Paraíba do Sul river basin. As criteria for allocation of costs, we used the volumes of water withdrawn and consumed, and the amount of effluent discharged into the river. In applying the methodology, we considered three different scenarios: "clean" basin, polluted basin, and an intermediate situation, closer to real situation now found in the sub-basin analyzed. The obtained results showed high dependence of the cost allocation criteria (weights assigned to the volumes of water withdrawn and consumed, and the quantity of effluent discharged), and, in the case of intermediate scenario considered, the values found indicate that the urban users should pay the greatest part of the costs when compared to the fees currently in use, since these users are among those that greatly discharge effluents, being the deterioration of water quality the most relevant problem in this basin