Distribuição de renda e pobreza no Brasil rural

Since the 60's, the population censuses have revealed a high degree of social inequality in Brazil. The concentration of income, as measured by the Gini index, showed persistently high since then. After the year 2001, we note that the trajectory stability is disrupted and the Gini index begins to show a downward trend. In relation to poverty, there has been two periods in recent history in which there was consistent decrease in the proportion of poor in the years immediately after the Real Plan in 2003 and in the year 2003 onwards. This research aimed to analyze poverty and income distribution in rural Brazil. In this crop sector, it is noted that the average perceived by the rural population is below the Brazilian income and, therefore, there is an increase in the number of poor. In addition, income in rural areas is less concentrated compared to the urban environment. Finally, as occurred in Brazil, there is a rural improvement in indicators of poverty and inequality in the last 10 years. Finally, this paper analyzes the changes that may have contributed to the fall in inequality and rural poverty, including the policy of rural settlement, the credit program to the family farmer (PRONAF) and rural retirement

Tsallis statistics and gradually truncated Levy flight - distribution of an economical index

Tsallis postulated a generalized form for entropy and give rise to a new statistics now known as Tsallis statistics. In the present work, we compare the Tsallis statistics with the gradually truncated Levy flight, and discuss the distribution of an economical index-the Standard and Poor's 500-using the values of standard deviation as calculated by our model. We find that both statistics give almost the same distribution. Thus we feel that gradual truncation of Levy distribution, after certain critical step size for describing complex systems, is a requirement of generalized thermodynamics or similar. The gradually truncated Levy flight is based on physical considerations and bring a better physical picture of the dynamics of the whole system. Tsallis statistics gives a theoretical support. Both statistics together can be utilized for the development of a more exact portfolio theory or to understand better the complexities in human and financial behaviors. A comparison of both statistics is made. (C) 2002 Published by Elsevier B.V. B.V.

Power-law distributions for the citation index of scientific publications and scientists

The number of citations of a scientific publication or of an individual scientist has become an important factor of quality assessment in science. We report a study of the statistical distribution of the citation index of both scientific publications and scientists. We give numerical evidence that Tsallis (power law) statistics explains the entire distribution over eight orders of magnitude (10-4 to 10(4)). Also, we draw Zipf plots in order to analyze the statistical distribution of the citation index of Brazilian and international physicists and chemists. The relatively small group of Brazilian scientists seems more adequate to explain the dynamics of the citation index. In this case, we find that the distribution of the citation index can also be explained by a gradually truncated power law with similar parameters. We finally discuss possible mechanisms behind the citation index of scientists and scientific publications.

The gradually truncated Levy flight for systems with power-law distributions

Power-law distributions have been observed in various economical and physical systems. Levy flights have infinite variance which discourage a physical approach. We introduce a class of stochastic processes, the gradually truncated Levy flight in which large steps of a Levy flight are gradually eliminated. It has finite variance and the system can be analyzed in a closed form. We applied the present method to explain the distribution of a particular economical index. The present method can be applied to describe time series in a variety of fields, i.e. turbulent flow, anomalous diffusion, polymers, etc. (C) 1999 Elsevier B.V. B.V. All rights reserved.