On the optimality of the Friedman Rule with heterogeneous agents and non-linear income taxation

We study the optimal “inflation tax” in an environment with heterogeneous agents and non-linear income taxes. We first derive the general conditions needed for the optimality of the Friedman rule in this setup. These general conditions are distinct in nature and more easily interpretable than those obtained in the literature with a representative agent and linear taxation. We then study two standard monetary specifications and derive their implications for the optimality of the Friedman rule. For the shopping-time model the Friedman rule is optimal with essentially no restrictions on preferences or transaction technologies. For the cash-credit model the Friedman rule is optimal if preferences are separable between the consumption goods and leisure, or if leisure shifts consumption towards the credit good. We also study a generalized model which nests both models as special cases.

Essays on household taxation and competition between heterogeneous firms

Essa tese é constituída por três artigos: "Tax Filing Choices for the Household", "Optimal Tax for the Household: Collective and Unitary Approaches" e "Vertical Differentiation and Heterogeneous Firms".

Main problems with the taxation of civil society organizations in Brazil: certifications and impact on payroll

The objective of this paper is to identify and analyze the main problems in the taxation—regarding both taxes themselves and compliance costs of taxation—of civil society organizations in Brazil. This study is qualitative descriptive research. A multiple case study with 26 organizations was performed. The results show that the problems mainly affect organizations with lower revenue and that do not work in the areas of education, health or social care. The main problems involve the taxation of the payroll and the difficulties related to obtaining and maintaining certifications. The study concludes with suggestions for the improvement of the regulatory framework.

Taxation of couples: a mirrleesian approach to collective households

Esta dissertação apresenta uma abordagem alternativa para o problema de taxação de famílias. Mais especificamente modelamos a decisão familiar com um modelo de barganha de Nash em que os o governo determina de forma ótima as utilidades de discórdia. Demonstramos um Princípio da Revelação para esse modelo de forma a reduzir a classe de mecanismos possíveis, além disso calculamos os ganhos do mecanismo ótimo em relação a outros mecanismos razoáveis por meio de exemplos. Discutimos algumas implicações associadas ao mecanismo ótimo.

CSR in South Africa mining sector

There are distinct ways in which mining companies in South Africa operate today that are different from the operations three decades ago. Companies have grown in proportion, and the extension of the businesses is directly proportional to the mining activities hence the ultimate prize of degradation and related challenges has to be faced. There is increasing need to understand the relationship between corporate social responsibility and company returns. Both the opponents and proponents of CSR argue their case through convincing arguments presented here concerning the subject as brought out in this discussion. The immediate stakeholders of any company are the consumers, and they form a critical component of the company’s operations. A study of the evolution of CSR Mining in South Africa strategies is critical; as brought out in the discussion of CSR strategies employed three decades ago with what is done today

Information mining and visualization of data from the Brazilian Supreme Court (STF): a case study

EMAp - Escola de Matemática Aplicada

Optimal Mirrleesian taxation in non-competitive labor markets

We study optimal labor income taxation in non-competitive labor markets. Firms offer screening contracts to workers who have private information about their productivity. A planner endowed with a Paretian social welfare function tries to induce allocations that maximize its objective. We provide necessary and sufficient conditions for implementation of constrained efficient allocations using tax schedules. All allocations that are implementable by a tax schedule display negative marginal tax rates for almost all workers. Not all allocations that are implementable in a competitive setting are implementable in this noncompetitive environment.

Impact assessment and quality analysis of corporate social responsability (CSR) programs of mining companies and their contribution to sustainable development in the communities they operate: case study Tenke Fungurume Mining SA in the Democratic Republic of Congo (DRC)

Purpose – This case study presents an impact assessment of Corporate Social Responsibility (CSR) programs of the TFM Company in order to understand how they contribute to the sustainable development of communities in areas in which they operate. Design/Methodology/Approach - Data for this study was collected using qualitative data methods that included semi-structured interviews and Focus Group Discussions most of them audio and video recorded. Documentary analysis and a field visit were also undertaken for the purpose of quality analysis of the CSR programs on the terrain. Data collected was analyzed using the Seven Questions to sustainability (7Qs) framework, an evaluation tool developed by the Mining, Minerals and Sustainable Development (MMSD) North America chapter. Content analysis method was on the other hand used to examine the interviews and FGDs of the study participants. Findings - Results shows that CSR programs of TFM SA do contribute to community development, as there have been notable changes in the communities’ living conditions. But whether they have contributed to sustainable development is not yet the case as programs that enhance the capacity of communities and other stakeholders to support these projects development beyond the implementation stage and the mines operation lifetime need to be considered and implemented. Originality/Value – In DRC, there is paucity of information of research studies that focus on impact assessment of CSR programs in general and specifically those of mining companies and their contribution to sustainable development of local communities. Many of the available studies cover issues of minerals and conflict or conflict minerals as mostly referred to. This study addressees this gap.

Mercury contamination in fanned fish setup on former garimpo mining areas in the Northern Mato Grosso State, Amazonian region, Brazil

The garimpo gold mining activity has released about 2.500 tons of mercury in the Brazilian Amazonian environment in the 1980-1995 period. The northern region of Mato Grosso State, an important gold mining and trading area during the Arnazonian gold rush is now at a turning point regarding its economic future. Nowadays, the activities related to gold mining have only a low relevance on its economy. Thus, the local communities are looking for economic alternatives for the development of the region. Cooperative fish farming is one of such alternatives. However, some projects are directly implemented on areas degraded by the former garimpo activity and the mercury left behind still poses risks, especially by its potential accumulation in fish. The objective of the present study was to evaluate the levels of mercury contamination in two fish farming areas, Paranaita and Alta Floresta, with and without records of past gold-washing activity, respectively. Data such as mercury concentration in fish of different trophic level, size, and weight as well as the water physical and chemical parameters were measured and considered. These preliminary data have shown no significant difference between these two fish fanning areas, relatively to mercury levels in fish. (c) 2004 Elsevier B.V. All rights reserved.

Perfil de beta talassemia heterozigota obtido a partir de análise data mining em banco de dados

Variations in the phenotypic expression of heterozygous beta thalassemia reflect the formation of different populations. To better understand the profile of heterozygous beta-thalassemia of the Brazilian population, we aimed at establishing parameters to direct the diagnosis of carriers and calculate the frequency from information stored in an electronic database. Using a Data Mining tool, we evaluated information on 10,960 blood samples deposited in a relational database. Over the years, improved diagnostic technology has facilitated the elucidation of suspected beta thalassemia heterozygote cases with an average frequency of 3.5% of referred cases. We also found that the Brazilian beta thalassemia trait has classic increases of Hb A2 and Hb F (60%), mainly caused by mutations in beta zero thalassemia, especially in the southeast of the country.

Fluvial transport of lead, zinc and copper contents in polluted mining regions

Ore mines installed in the lower-middle portion of Ribeira de Iguape River (São Paulo State, southeastern Brazil), together with the Panelas Plant are responsible for the contamination of the Iguape-Cananeia-Paranagua lagoon-estuarine complex. The lower-middle portion of Grande Creek Basin, located in the district of Adrianopolis (Parana State, southern Brazil) is under environmental impact because of mining activities. The mines of Perau, at Perau Creek, Canoas at Canoas Creek, and Barrinha at Barrinha Creek and Laranjal Creek have been paralyzed. The transport of lead in fluvial sediments is mainly associated with organic matter, carbonates, the residual fraction, and adsorbables, whereas the transport of zinc is associated with the organic and residual fraction, oxides and hydroxides of iron and manganese, carbonate, and adsorbables. The transport of copper is associated with the residual fraction and oxides and hydroxides of iron and manganese, organic matter, carbonate, and adsorbables.

Flow rate and hydrochemistry in areas of sand mining activities

This investigation reports the results of a study realized in areas related to the development of sand mining activities, which belong to CRS-Mineragao Industria e Comercio Ltd. and Sibelco Mineracao Ltd. Both areas are located around Analandia municipality, nearly in the center of São Paulo State, Brazil. Flow rate and hydrochemical analyses were realized over different periods of time, with the aim of evaluating the possibility of release of several constituents to the liquid phase, which may be a source of pollution of the surface hydrological resources. This is because some tributaries from the Corumbatai River may be suffering contamination, implying on the impoverishment of the water quality that is a very important resource in the region, as it is extensively used for drinking purposes, among others.

Impact of coal mining on water quality of three artificial lakes in Morozini River Basin (Treviso, Santa Catarina State, Brazil)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Mercury in soils and sediments from gold mining liabilities in Southern Amazonia

The 1980-1990 Amazonian gold rush left an enormous liability that increasingly has been substituted by developing fish aquaculture. This work aimed at the identification of the mercury levels in the environment, associated with fish farms located in the North of Mato Grosso State, Southern Amazon. Sediment and soil samples were analyzed for total organic carbon and total mercury. Results indicate that the chemical characteristics of the sediment largely depend on the management procedures of the fish pond (liming, fish food used and fish population). The soils presented relatively low concentrations when compared with other data from the literature.