Least-action principle and path-integral for classical mechanics

In this paper we show how the equations of motion of a superfield, which makes its appearance in a path-integral approach to classical mechanics, can be derived without the need of the least-action principleComment: to appear IN PHYS.REV.D (Brief Report

Costs and Benefits of Privatization: Evidence from Brazil

Although the Brazilian privatization program has been a sweeping endeavor involving more than 100 firms and billions of dollars, most of the studies have been published only in Brazil, and in Portuguese. This paper is the most comprehensive study to date in terms of the companies covered, and includes the most recent data. It looks at the results of privatization in Brazil for a broad range of economic variables to answer the question: Has the widespread popular discontent with the program been justified? The paper also examines the effects of privatization on aspects that affect the development of financial markets, including minority shareholder rights. It concludes with recommendations for democratizing capital ownership through public offers in which workers would be entitled to participate using public sector liabilities such as FGTS deposits.

Comment on "Effects of cosmic-string framework on the thermodynamical properties of anharmonic oscillator using the ordinary statistics and the q-deformed superstatistics approaches"

We point out a misleading treatment in a recent paper published in this Journal [Eur. Phys. J. C (2018)78:106] regarding solutions for the Schr\"{o}dinger equation with a anharmonic oscillator potential embedded in the background of a cosmic string mapped into biconfluent Heun equation. This fact jeopardizes the thermodynamical properties calculated in this system.Comment: 3 page

Bioenergia e exclusão regional: a não política nacional agroenergética e os girassóis do RN

This doctoral thesis presents an analysis of the production of bicarbonates and related regional development in Brazil. It is widely believed that one of Brazil s vocations lies in the agro-energy sector. However, current national agro-energy policies, together with the experience of Petrobras (the national oil company) in rural settlements in the state of Rio Grande do Norte, show that Brazil has fallen short of effectively including the North and Northeast regions of the country, let alone small-scale rural producers (residing in rural settlements or not), in the development process and related benefits from the country s participation in the current world energy grid. The methodology entails secondary research related to the theme, such as books, official documents, websites and statistical databases from diverse sources, in addition to an analysis of statements from interviews of Petrobras representatives and other important scientific, institutional and labor union authorities, in relation to agro-energy issues and the socio-economic participation of family-based agriculture in this process. Principal findings show a correlation between agro-energy and regional development, creating the potential for numerous opportunities and challenges. Findings demonstrate the possibility of reversing/reducing historically rooted indices of hunger and poverty that continue to devastate the North and Northeast regions. At the same time, the thesis points to a potentially catastrophic increase in regional disparities, should the present historic moment not be seized upon so as to include these regions. Classic examples of non-policy at the federal level are presented as evidence of the absence of a regionally focused agroenergy policy in the current government, reinforced by the experiences of Petrobras in the Rio Grande do Norte rural settlements. Finally, the thesis concludes that there is an urgent need to create a government-sponsored enterprise (with a structure similar to Petrobras) with the purpose of implementing a truly broad and inclusive development process for the bicarbonates production sector, while remaining attentive to Brazil s opportune and critical role in the world s current agro-energy scenario.Analisa a relação entre a produção de biocarburantes e a questão regional. Acredita-se que a produção agroenergética é uma vocação brasileira, contudo, a atual política nacional agoenergética e a experiência dos assentamentos rurais apoiados pela Petrobras, no Rio Grande do Norte, não incluem efetivamente as regiões Norte e Nordeste do Brasil, tampouco os pequenos produtores rurais (assentados ou não) nos benefícios decorrentes da atual mudança na matriz energética mundial. A metodologia utilizada inclui a pesquisa secundária concernente ao tema, tais como livros, documentos oficiais, sites, bases estatísticas entre as demais fontes, e ainda a análise de discurso tomando por base entrevistas realizadas junto à Petrobras e com importantes autoridades científicas, institucionais e sindicais relacionadas à questão agroenergética e a inclusão sócio-econômica da agricultura familiar neste processo. Os principais resultados indicam que a correlação entre agroenergia e a questão regional apresenta inúmeras potencialidades e desafios. Aponta para a possibilidade de reversão/redução dos históricos indicadores de fome e pobreza que assolam o Norte e o Nordeste. Contudo, também indica que a não política agroenergética no atual governo federal, assim como experiências da Petrobras nos assentamentos do Rio Grande do Norte são exemplos claros de não política que podem agravar o quadro de disparidades regionais de forma abissal, caso não haja aproveitamento deste momento histórico. Por fim conclui que urge a criação de uma empresa de economia mista (nos moldes da Petrobras) e integradora especializada na produção de biocarburantes, que trate desta questão com a urgência e importância que o Brasil ocupa no cenário agroenergético mundial, numa perspectiva verdadeiramente includente e abrangente

Evolution of statistical analysis in empirical software engineering research: Current state and steps forward

Software engineering research is evolving and papers are increasingly based on empirical data from a multitude of sources, using statistical tests to determine if and to what degree empirical evidence supports their hypotheses. To investigate the practices and trends of statistical analysis in empirical software engineering (ESE), this paper presents a review of a large pool of papers from top-ranked software engineering journals. First, we manually reviewed 161 papers and in the second phase of our method, we conducted a more extensive semi-automatic classification of papers spanning the years 2001--2015 and 5,196 papers. Results from both review steps was used to: i) identify and analyze the predominant practices in ESE (e.g., using t-test or ANOVA), as well as relevant trends in usage of specific statistical methods (e.g., nonparametric tests and effect size measures) and, ii) develop a conceptual model for a statistical analysis workflow with suggestions on how to apply different statistical methods as well as guidelines to avoid pitfalls. Lastly, we confirm existing claims that current ESE practices lack a standard to report practical significance of results. We illustrate how practical significance can be discussed in terms of both the statistical analysis and in the practitioner's context.Comment: journal submission, 34 pages, 8 figure