Análise da dentina de dentes decíduos submetidos ao capeamento pulpar indireto

O objetivo do estudo foi avaliar as características da dentina cariada remanescente de molares decíduos quanto à coloração, consistência e microdureza, após um período médio de 3 anos e 8 meses da realização do capeamento pulpar indireto. O estudo clínico constou de 27 dentes que apresentavam lesões cariosas ativas com expressão radiográfica em metade interna de dentina. Aleatoriamente, foi realizado o capeamento pulpar indireto e utilizado como material capeador o hidróxido de cálcio (HC) e o cimento de ionômero de vidro resinoso modificado (CIVRM). As crianças foram acompanhadas através de exames clínicos e radiográficos, e ao longo de um período médio de 3 anos e 8 meses, observou-se um índice de sucesso de 89% para o grupo do HC e de 93% para o CIVRM, não havendo diferença estatisticamente significante entre os dois grupos (p=0,62). Os dentes considerados como sucesso no estudo clínico foram agrupados em um único grupo (grupo teste), que constou de 13 dentes que sofreram esfoliação natural ou exodontia por motivos ortodônticos. Além disso, foram selecionados 15 molares decíduos hígidos (grupo controle positivo) e 15, portadores de lesões cariosas ativas em metade interna de dentina (grupo controle negativo). As amostras do grupo teste tiveram suas respectivas restaurações removidas, a profundidade medida e a dentina remanescente avaliada por um operador calibrado, seguindo critérios descritivos, quanto à consistência e a coloração. Nos dentes do grupo controle positivo, foram realizados preparos cavitários oclusais em até 4 mm de profundidade, enquanto que, no grupo controle negativo, o mesmo operador do estudo clínico realizou a remoção parcial de tecido cariado in vitro. A partir daí, todos os dentes foram preparados para análise de microdureza, que foi realizada por um examinador calibrado, que empregou o princípio de cegamento. Na análise da consistência, todos os dentes do grupo teste (n=13) apresentaram-se endurecidos, enquanto que 9, apresentaram coloração amarela-clara (8 do CIVRM e 1 do HC) e 4, castanho-escura (1 do CIVRM e 3 do HC). Para o teste de microdureza no grupo teste, obteve-se uma média KHN de 40,81 (±16,28) MPa, enquanto que nos grupos controles positivo e negativo, foram alcançados valores médios de 62,73 (±11,24) MPa e 19,15 (±6,99) MPa, respectivamente. A análise estatística mediante o teste ANOVA indicou que houve diferença significativa entre os 3 grupos. Foi constatada a remineralização da dentina de dentes decíduos em que foi realizada a técnica do capeamento pulpar indireto após um período médio de 3 anos e 8 meses, através de critérios clínico (consistência) e laboratorial (análise da microdureza).

The costs of education, longevity and the poverty of nations

This paper explores the distortions on the cost of education, associated with government policies and institutional factors, as an additional determinant of cross-country income differences. Agents are finitely lived and the model takes into account life-cycle features of human capital accumulation. There are two sectors, one producing goods and the other providing educational services. The model is calibrated and simulated for 89 economies. We find that human capital taxation has a relevant impact on incomes, which is amplified by its indirect effect on returns to physical capital. Life expectancy plays an important role in determining long-run output: the expansion of the population working life increases the present value of the flow of wages, which induces further human capital investment and raises incomes. Although in our simulations the largest gains are observed when productivity is equated across countries, changes in longevity and in the incentives to educational investment are too relevant to ignore.

Estratégia na prestação de serviços de transporte rodoviário de mercadorias no Brasil

O setor de transporte de mercadorias é atualmente um dos mais importantes setores da economia brasileira, por esse motivo o presente estudo tem a intenção de realizar uma analise da estratégia aplicada à prestação de serviços com foco nesta modalidade de serviços, já que é escasso o numero de estudos dedicados a compreensão deste segmento em especifico. Assim esta pesquisa tem como objetivo a analise dos aspectos estratégicos desta prestação de serviços e o pressuposto, a ser aferido ao fim, de que estas empresas seguem e adotam estratégias empresariais não formais e predominantemente empíricas, pouco alinhadas às vantagens competitivas esperadas ao setor. O conteúdo teórico esta compreendido na pesquisa com a função primordial de fundamentar as percepções colhidas em campo e para dar consistência à pesquisa qualitativa realizada junto a um grupo de empresas de transporte deste segmento

Structural Transformation and Productivity in Latin America

We investigate the role of sectorial differences in labor productivity and the process of structural transformation (reallocation of labor across sectors) in accounting for the time path of aggregate productivity across six Latin American countries (Brazil, Chile, Argentina, Colombia, Mexico and Venezuela) from 1950 to 2003. We used a general equilibrium model with three sectors (agriculture, industry and services) calibrated to those six economies. The model is used to compare the trajectory of productivity in each sector of activity with that of the United States and it impact on aggregate productivity.While in Brazil and Argentina, the Service Sector was responsible for reversing the process of catch up in productivity that occurred until the 1980s, in others, like Colombia, Mexico and Venezuela, low productivity growth of the three sectors explain their poor performance.

Targeting the poor: a macroeconomic analysis of cash transfer programs

This paper introduces cash transfers targeting the poor in an incomplete markets model with heterogeneous agents facing idiosyncratic risk. These transfers change the degree of insurance in the economy and affect precautionary motives asymmetrically, leading the poorest households to decrease savings proportionally more than their richer counterparts. In a model economy calibrated to Brazil, once the cash transfer program is adopted, wealth inequality and social welfare increase, poverty decreases, while employment and income inequality remain about the same. Imperfect access to financial markets is important for these results, whereas whether the program is funded with lump sum or distortive taxes is not.

The effect of social security, health, demography and technology on retirement

This article studies the determinants of the labor force participation of the elderly and investigates the factors that may account for the increase in retirement in the second half of the last century. We develop a life-cycle general equilibrium model with endogenous retirement that embeds Social Security legislation and Medicare. Individuals are ex ante heterogeneous with respect to their preferences for leisure and face uncertainty about labor productivity, health status and out-of-pocket medical expenses. The model is calibrated to the U.S. economy in 2000 and is able to reproduce very closely the retirement behavior of the American population. It reproduces the peaks in the distribution of Social Security applications at ages 62 and 65 and the observed facts that low earners and unhealthy individuals retire earlier. It also matches very closely the increase in retirement from 1950 to 2000. Changes in Social Security policy - which became much more generous - and the introduction of Medicare account for most of the expansion of retirement. In contrast, the isolated impact of the increase in longevity was a delaying of retirement.

Fiscal multipliers in an incomplete markets economy

This paper studies the behavior of fiscal multipliers in two different economic environments: complete markets and incomplete markets. Based on steady state analysis, output multipliers are found within a range between 0.49 and 0.66, when the markets are complete. Under incomplete markets, output multiplier was found in an interval between 0.75 and 0.94. These results indicates that the market structure, which reflects the degree of risk sharing and the intensity of the precautionary motive faced by individuals, plays a key role in determining the fiscal multipliers. In the second part of the paper, was performed an exercise to analyze the dynamic response of macroeconomic aggregates to an exogenous and unexpected rise in government spending financed by lump-sum taxes. In this case, impact output multipliers varies in a range between 0.64 and 0.68, under complete markets, and within 1.05 and 1.20 when markets are incomplete. The results found under incomplete markets are very close to that found on related literature which usually uses an econometric approach or calibrated/estimated New Keynesian models. These results shows that taking into account the deficiencies in the insurance mechanisms can be an interesting way to reconcile theoretical models with the results found on related current literature, without the need of ad-hoc assumptions relative to price stickness.

Essays in heterogeneous agent macroeconomics

This thesis is comprised of three chapters. The first article studies the determinants of the labor force participation of elderly American males and investigates the factors that may account for the changes in retirement between 1950 and 2000. We develop a life-cycle general equilibrium model with endogenous retirement that embeds Social Security legislation and Medicare. Individuals are ex ante heterogeneous with respect to their preferences for leisure and face uncertainty about labor productivity, health status and out-of-pocket medical expenses. The model is calibrated to the U.S. economy in 2000 and is able to reproduce very closely the retirement behavior of the American population. It reproduces the peaks in the distribution of Social Security applications at ages 62 and 65 and the observed facts that low earners and unhealthy individuals retire earlier. It also matches very closely the increase in retirement from 1950 to 2000. Changes in Social Security policy - which became much more generous - and the introduction of Medicare account for most of the expansion of retirement. In contrast, the isolated impact of the increase in longevity was a delaying of retirement. In the second article, I develop an overlapping generations model of criminal behavior, which extends prior research on crime by taking into account individuals' labor supply decisions and the stigma effect that affects convicted offenders, lowering their likelihood of employment. I use the model to guide a quantitative assessment of the determinants of crime and of a counterfactual experiment in which an income redistribution policy is thought as an alternative to greater law enforcement. The model economy considered in this paper is populated by heterogeneous agents who live for a realistic number of periods, have preferences over consumption and leisure, and differ in terms of their age, their skills as well as their employment shocks. In addition, savings may be precautionary and allow partial insurance against the labor income shocks. Because of the lack of full insurance, this model generates an endogenous distribution of wealth across consumers, enabling us to assess the welfare implications of the redistribution policy experiment. I calibrated the model using the US data for 1980 and then use the model to investigate the changes in criminality between 1980 and 1996. The main results that come out of this study are: 1) Law enforcement policy was the most important factor behind the fall in criminality in the period, while the increase in inequality was the most important single factor promoting crime; 2) Stigmatization is not a free-cost crime control policy; 3) Income redistribution can be a powerful alternative policy to fight crime. Finally, the third article studies the impact of HIV/AIDS on per capita income and education. It explores two channels from HIV/AIDS to income that have not been sufficiently stressed by the literature: the reduction of the incentives to study due to shorter expected longevity and the reduction of productivity of experienced workers. In the model individuals live for three periods, may get infected in the second period and with some probability die of Aids before reaching the third period of their life. Parents care for the welfare of the future generations so that they will maximize lifetime utility of their dynasty. The simulations predict that the most affected countries in Sub-Saharan Africa will be in the future, on average, thirty percent poorer than they would be without AIDS. Schooling will decline in some cases by forty percent. These figures are dramatically reduced with widespread medical treatment, as it increases the survival probability and productivity of infected individuals.

Structural transformation and productivity in Latin America

This article examines the e¤ects of sectorial shifts and structural transformation on the recent productivity path of Latin America. We use a four-sector (agriculture, industry, modern services and traditional services) general equilibrium model calibrated to the main economies in the region. The model very closely replicates labor reallocations across sectors and the growth of aggregate labor productivity from 1950 to 2005. Structural transformation explains a sizeable portion of the region s convergence in the rst decades. In most cases, the poor performance of the traditional services sector is the main cause of the slowdown in productivity growth observed in the region after the mid-1970s and is a key factor in explaining the divergence during this period.

Distortions in the investment goods sector and productivity decline

We study the impact of distortions in the investment goods sector on aggregate total factor productivity (TFP). We develop a two-sector neo-classical growth model in which TFP in the capital goods sector relative to TFP in the consumption sector is inversely related to the price of investment relative to consumption, so that we use relative prices to measure TFP in the investment goods sector. The model is calibrated to Brazil and we nd that distortions in the investment goods sector may explain most of the decline in Brazilian TFP relative to the United States since the mid-1970s.

The life-cycle effects of social security in a model with housing and endogenous benefits

This article develops a life-cycle general equilibrium model with heterogeneous agents who make choices of nondurables consumption, investment in homeowned housing and labour supply. Agents retire from an specific age and receive Social Security benefits which are dependant on average past earnings. The model is calibrated, numerically solved and is able to match stylized U.S. aggregate statistics and to generate average life-cycle profiles of its decision variables consistent with data and literature. We also conduct an exercise of complete elimination of the Social Security system and compare its results with the benchmark economy. The results enable us to emphasize the importance of endogenous labour supply and benefits for agents' consumption-smoothing behaviour.

Arrecadação governamental e sistema tributário como resultados políticos

Esse paper introduz escolha simultânea do sistema político, sistema tributário e composição do gasto governamental em um modelo macroeconômico dinâmico de economia política com mercados incompletos onde o tamanho das arrecadações governamentais deve ser decidido a cada período. Além disso avalia o efeito de cada uma dessas instituições sobre a política fiscal de equilíbrio político. A inclusão dessas variáveis torna o modelo mais realista e possibilita o estudo de como a política econômica do governo é escolhida pela sociedade. A especificação mais geral do modelo calibrada para os EUA foi capaz de aproximar de maneira satisfatória a taxa efetiva e a relação tributária capital-trabalho observada nos dados.

Rational expectations and the service of public debt: a recursive approach

This paper uses dynamic programming to study the time consistency of optimal macroeconomic policy in economies with recurring public deficits. To this end, a general equilibrium recursive model introduced in Chang (1998) is extended to include govemment bonds and production. The original mode! presents a Sidrauski economy with money and transfers only, implying that the need for govemment fmancing through the inflation tax is minimal. The extended model introduces govemment expenditures and a deficit-financing scheme, analyzing the SargentWallace (1981) problem: recurring deficits may lead the govemment to default on part of its public debt through inflation. The methodology allows for the computation of the set of alI sustainable stabilization plans even when the govemment cannot pre-commit to an optimal inflation path. This is done through value function iterations, which can be done on a computeI. The parameters of the extended model are calibrated with Brazilian data, using as case study three Brazilian stabilization attempts: the Cruzado (1986), Collor (1990) and the Real (1994) plans. The calibration of the parameters of the extended model is straightforward, but its numerical solution proves unfeasible due to a dimensionality problem in the algorithm arising from limitations of available computer technology. However, a numerical solution using the original algorithm and some calibrated parameters is obtained. Results indicate that in the absence of govemment bonds or production only the Real Plan is sustainable in the long run. The numerical solution of the extended algorithm is left for future research.

Mobility, targeting and private school vouchers

This paper uses general equilibrium simulations to explore the role ofresidential mobility in shaping the impact of different types of private school voucher policies. In particular, general vouchers available to all residents in the state are compared to vouchers specifically targeted to either underprivileged school districts or underprivileged households. The simulations are derived from a three-community mo deI of low, middle and high income school districts (calibrated to New York data), where each school district is composed of multiple types of neighborhoods that may vary in house quality as well as the leveI of neighborhood extemalities. Households that differ in both their income and in the ability leveI of their children choose between school districts, between neighborhoods within their school district, and between the local public school or a menu of private school altematives.Local public school quality within a district is endogenously determined bya combination of the average peer quality of public school attending children as well as local property and state income tax supported spending. Financial support (above a required state minimum) is set by local majority rule. Finally, there exists the potential for a private school market composed of competitive schools that face production technologies similar to those ofpublic schools but who set tuition and admissions policies to maximize profits. In tbis model, it is demonstrated that school district targeted vouchers are similar in their impact to non-targeted vouchers but vastIy different from vouchers targeted to low income households. Furthermore, strong migration effects are shown to significantly improve the likely equity consequences of voucher programs.

Export-led recoveries in small open industrialized economies

This paper studies the role of Vertical Specialization-based trade and foreign damand push as elements capable of explaining export-led recoveries in small open industrialized economies. The empirical evidence on export-led recoveries is reviewed. Data supporting the growing importance of vertical specialization for international trade are presented. I compare the performance of two versions of a small open economy model, calibrated to mimic Canadian Business Cycles. The …rst one is based upon Schmitt-Grohe(1998). The second incorporates Vertical- Specialization-based trade. I show that an arti…cial economy featuring Vertical-Specializationbased trade in conjunction with an exogenous AR(2) process for foreign output displays improved impulse responses to a foreign output shock and is able to mimic the contribution of Canadian exports to output growth during economic recoveries.