Segmentation in the brazilian labor market

This paper measures the degree of segmentation in the brazilian labor market. Controlling for observable and unobservable characteristics, workers earn more in the formal sector, which supports the segmentation hypothesis. We break down the degree of segmentation by socio-economic attributes to identify the groups where this phenomenon is more prevalent. We investigate the robustness of our findings to the inclusion of self-employed individuals, and apply a two-stage panel probit model using the self-selection correction strategy to investigate a potential weakness of the fixed-effects estimator

Nonparametric entropy-based tests of independence between stochastic processes

This paper develops nonparametric tests of independence between two stationary stochastic processes. The testing strategy boils down to gauging the closeness between the joint and the product of the marginal stationary densities. For that purpose, I take advantage of a generalized entropic measure so as to build a class of nonparametric tests of independence. Asymptotic normality and local power are derived using the functional delta method for kernels, whereas finite sample properties are investigated through Monte Carlo simulations.

Eficiência na arrecadação de tributos: análise através de uma fronteira estocástica de custo aplicada as delegacias da Receita Federal do Brasil

O presente estudo pretende avaliar o desempenho das Delegacias da Receita Federal através do estabelecimento de uma fronteira de eficiência paramétrica baseada nos custos, utilizando para tal um modelo estocástico que divide o ruído em dois componentes, sendo um aleatório e outro proveniente da ineficiência de cada unidade. O trabalho terá por base dados relativos aos anos de 2006 e 2008 em uma análise em corte transversal e visa avaliar a política pública de unificação dos órgãos estatais responsáveis pela arrecadação de tributos em nível Federal, a Secretaria da Receita Federal (SRF) com a Secretaria da Receita Previdenciária (SRP), ocorrida através da lei 11.457 de 16 de março de 2007. O objetivo principal da pesquisa é determinar se as unidades descentralizadas da Receita Federal, notadamente as Delegacias da Receita Federal estão operando com eficiência, na tarefa de arrecadar tributos, em função dos recursos colocados a disposição para execução de suas atividades. Na presente pesquisa o produto da unidade a ser avaliado é a arrecadação, dentre as inúmeras atividades realizadas pelo órgão, no sentido de proporcionar ao Estado recurso para implantação de Políticas Públicas. O resultado encontrado indica que as regiões onde existe um grande número de empresas optantes pelo regime de tributação do SIMPLES, bem como as que possuem em sua jurisdição empresas consideradas DIFERENCIADAS pelo seu porte, provocam um aumento nos custos das Delegacias. As unidades que se encontram nas capitais dos Estados melhoraram o seu desempenho após a unificação. Além disso, uma proporção maior de Auditores Fiscais dentro da Delegacia em relação ao total de servidores reduz a ineficiência. O trabalho espera contribuir na avaliação desse novo modelo de gestão implantado na administração tributária federal no país.

Conditional labour supply, quantile functions in Brazil

The estimation of labor supply elasticities has been an important issue m the economic literature. Yet all works have estimated conditional mean labor supply functions only. The objective of this paper is to obtain more information on labor supply, by estimating the conditional quantile labor supply function. vI/e use a sample of prime age urban males employees in Brazil. Two stage estimators are used as the net wage and virtual income are found to be endogenous to the model. Contrary to previous works using conditional mean estimators, it is found that labor supply elasticities vary significantly and asymmetrically across hours of work. vVhile the income and wage elasticities at the standard work week are zero, for those working longer hours the elasticities are negative.

All-pay auctions with endogenous asymmetries

We study N-bidders, asymmetric all-pay auctions under incomplete information. First, we solve for the equilibrium of a parametric model. Each bidder’s valuation is independently drawn from an uniform [0, αi] where the parameter αi may vary across bidders. In this game, asymmetries are exogenously given. Next, a two-stage game where asymmetries are endogenously generated is studied. At the first stage, each bidder chooses the level of an observable, costly, value-enhancing action. The second stage is the bidding sub-game, whose equilibrium is simply the equilibrium of the, previously analyzed, game with exogenous asymmetries. Finally, natural applications of the all pay-auction in the context of political lobbying are considered: the effects of excluding bidders, as well as, the impact of caps on bids.

Phase transition of demand explained by the heterogeneity of consumers' intrinsic preferences

In 1991 Gary S. Becker presented A Note on Restaurant Pricing and Other Examples of Social In uences on Price explaining why many successful restaurants, plays, sporting events, and other activities do not raise their prices even with persistent excess demand. The main reason for this is due to the discontinuity of stable demands, which is explained in Becker's (1991) analysis. In the present paper we construct a discrete time stochastic model of socially interacting consumers deciding for one of two establishments. With this model we show that the discontinuity of stable demands, proposed by Gary S. Becker, depends crucially on an additional factor: the dispersion of the consumers' intrinsic preferences for the establishments.

On the effects of non-tariff measures on Brazilian exports

This article proposes an alternative methodology for estimating the effects of non-tariff measures on trade flows, based on the recent literature on gravity models. A two-stage Heckman selection model is applied to the case of Brazilian exports, where the second stage gravity equation is theoretically grounded on the seminal Melitz model of heterogeneous firms. This extended gravity equation highlights the role played by zero trade flows as well as firm heterogeneity in explaining bilateral trade among countries, two factors usually omitted in traditional gravity specifications found in previous literature. Last, it also proposes a economic rationale for the effects of NTM on trade flows, helping to shed some light on its main operating channels under a rather simple Cournot’s duopolistic competition framework.

Creditor's protection and bank loans: lack of competition hamprers bankruptcy reform's effects

This dissertation investigates how credit institutions’ market power limits the effects of creditor protection rules on the interest rate and the spread of bank loans. We use the Brazilian Bankruptcy Reform of June/2005 (BBR) as a legal event affecting the institutional environment of the Brazilian credit market. The law augments creditor protection and aims to improve the access of firms to the credit market and to reduce the cost of borrowing. Either access to credit or the credit cost are also determined by bank industry competition and the market power of suppliers of credit. We derive a simple economic model to study the effect of market power interacting with cost of lending. Using an accounting and operations dataset from July/2004 to December/2007 provided by the Brazilian Central Bank, we estimate that the lack of competition in the bank lending industry hinders the potential reducing effect of the BBR on the interest rate of corporate loans by approximately 30% and on the spread by approximately 23%. We also find no statistical evidence that the BBR affected the concentration level of the Brazilian credit market. We present a brief report on bankruptcy reforms around the world, the changes in the Brazilian legislation and on some recent related articles in our introductory chapter. The second chapter presents the economic model and the testable hypothesis on how the lack of competition in the lending market limits the effects of improved creditor protection. In this chapter, we introduce our empirical strategy using a differences-in-differences model and we estimate the limiting effect of market power on the BBR’s potential to reduce interest rates and on the spread of bank loans. We use the BBR as an exogenous event that affects collateralized corporate loans (treatment group) but that does not affect clean consumer loans (control group) to identify these effects, using different concentration measures. In Chapter 3, we propose a two-stage empirical strategy to handle the H–Statistics proposed by Panzar and Rosse as a measure of market competition. We estimate the limiting effects of the lack of competition in replacing the concentration statistics by the H–Statistics. Chapter 4 presents a structural break test of the concentration index and checks if the BBR affects the dynamic evolution of the concentration index.

Tributação de energia elétrica e bem-estar social: uma análise regional

Os reflexos da tributação sobre o setor elétrico ultrapassam as questões meramente arrecadatórias de estados, municípios e União, envolvem toda a produção do país e o bem-estar de sua população. Neste contexto, e com o intuito de trazer as questões de eficiência e redistributividade ao ambiente de tributação de energia elétrica, o presente trabalho pretende apresentar um panorama da tributação atual do consumo residencial de energia elétrica, principalmente em relação ao ICMS, juntamente com um cálculo simplificado de alíquotas considerando dois modelos de tributação ótima, estabelecidos por F. R. Ramsey e Diamond e Mirrlees, a partir dos quais é possível realizar comparações em relação ao modelo atual e sintetizar uma visão nacional de uma tributação realizada em sua maior parte regionalmente. O primeiro modelo considera apenas eficiência na definição das alíquotas aplicadas aos produtos, partindo da premissa de que todos os consumidores são idênticos e não há preocupações com equidade. As elasticidades necessárias para aplicação do critério de Ramsey são estimadas a partir de dados em painel das 64 distribuidoras de energia elétrica do país, utilizando um modelo em dois estágios com variável instrumental. O segundo modelo, proposto por Diamond e Mirrlees, incorpora a equidade na modelagem, introduzindo a diferenciação entre os indivíduos.

On the effects of non tariff measures on Brazilian exports

This article proposes an alternative methodology for estimating the effects of non-tariff measures on trade flows, based on the recent literature on gravity models. A two-stage Heckman selection model is applied to the case of Brazilian exports, where the second stage gravity equation is theoretically grounded on the seminal Melitz model of heterogeneous firms. This extended gravity equation highlights the role played by zero trade flows as well as firm heterogeneity in explaining bilateral trade among countries, two factors usually omitted in traditional gravity specifications found in previous literature. Last, it also proposes a economic rationale for the effects of NTM on trade flows, helping to shed some light on its main operating channels under a rather simple Cournot’s duopolistic competition framework

Temporal variability of soil CO2 emission after conventional and reduced tillage described by an exponential decay in time model

A quantificação do impacto das práticas de preparo sobre as perdas de carbono do solo é dependente da habilidade de se descrever a variabilidade temporal da emissão de CO2 do solo após preparo. Tem sido sugerido que as grandes quantidades de CO2 emitido após o preparo do solo podem servir como um indicador das modificações nos estoques de carbono do solo em longo termo. Neste trabalho é apresentado um modelo de duas partes baseado na temperatura e na umidade do solo e que inclui um termo exponencial decrescente do tempo que é eficiente no ajuste das emissões intermediárias após preparo: arado de disco seguido de uma passagem com a grade niveladora (convencional) e escarificador de arrasto seguido da passagem com rolo destorroador (reduzido). As emissões após o preparo do solo são descritas utilizando-se estimativa não linear com um coeficiente de determinação (R²) tão alto quanto 0.98 após preparo reduzido. Os resultados indicam que nas previsões da emissão de CO2 após o preparo do solo é importante considerar um termo exponencial decrescente no tempo após preparo.

Dynamics of extinction in coupled populations of the flour beetle Tribolium castaneum

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Radiative Omega(-)->Xi(-)gamma decay and physics beyond the standard model

We investigate the impact of new physics beyond the Standard Model to the s --> d gamma process, which is responsible for the short-distance contribution to the radiative decay Omega-( )--> Xi(-) gamma. We study three representative extensions of the Standard Model, namely a one-family technicolor model, a two Higgs doublet model and a model containing scalar leptoquarks. When constraints arising from the observed b --> s gamma transition and the upper limit on D-0-(D) over bar(0) mixing are taken into account, we find no significant contributions of new physics to the s --> d gamma process.

Dynamic critical behavior of percolation observables in the 2d Ising model

We present preliminary results of our numerical study of the critical dynamics of percolation observables for the two-dimensional Ising model. We consider the (Monte-Carlo) short-time evolution of the system obtained with a local heat-bath method and with the global Swendsen-Wang algorithm. In both cases, we find qualitatively different dynamic behaviors for the magnetization and Omega, the order parameter of the percolation transition. This may have implications for the recent attempts to describe the dynamics of the QCD phase transition using cluster observables.

Microscopic origin of non-Gaussian distributions of financial returns

In this paper we study the possible microscopic origin of heavy-tailed probability density distributions for the price variation of financial instruments. We extend the standard log-normal process to include another random component in the so-called stochastic volatility models. We study these models under an assumption, akin to the Born-Oppenheimer approximation, in which the volatility has already relaxed to its equilibrium distribution and acts as a background to the evolution of the price process. In this approximation, we show that all models of stochastic volatility should exhibit a scaling relation in the time lag of zero-drift modified log-returns. We verify that the Dow-Jones Industrial Average index indeed follows this scaling. We then focus on two popular stochastic volatility models, the Heston and Hull-White models. In particular, we show that in the Hull-White model the resulting probability distribution of log-returns in this approximation corresponds to the Tsallis (t-Student) distribution. The Tsallis parameters are given in terms of the microscopic stochastic volatility model. Finally, we show that the log-returns for 30 years Dow Jones index data is well fitted by a Tsallis distribution, obtaining the relevant parameters. (c) 2007 Elsevier B.V. All rights reserved.