The Discretionary Effect of CEOs and Board Chairs on Corporate Governance Structures

In this study we analyze the effect of latent managerial characteristics on corporate governance. We find that CEO and board chair fixed effects explain a significant portion of the variation in board size, board independence, and CEO-chair duality even after controlling for several firm characteristics and firm fixed effects. The effect of CEOs on corporate governance practices is attributable mainly to executives who simultaneously hold the position of CEO and board chair in the same firm. Our results do not show a decline in CEO discretionary influence on corporate governance after the enactment of the Sarbanes–Oxley Act and stock exchange governance regulations

The Flash Crash: An Examination of Shareholder Wealth and Market Quality

We investigate stock returns, market quality, and options market activity around the flash crash of May 6, 2010. Abnormal returns are negative on the day of and the day after the flash crash for stocks that had trades that executed during the crash subsequently cancelled by either Nasdaq or NYSE Arca. Consistent with studies that suggest that other sources of liquidity withdrew from the markets during the flash crash, we find that the fraction of trades executed by the NYSE increases during this volatile period. Market quality deteriorates following the flash crash as bid-ask spreads increase and quote depths decrease. Evidence from the options markets indicates that investor uncertainty increased around the time of the crash and remained elevated for several days

Modelagem numérica do escoamento transiente churn-anular em tubulações verticais e sua aplicação na simulação de carga de líquido em poços de gás

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Mecânica, Florianópolis, 2014.Na produção de gás natural, é de grande importância que todo e qualquer líquido presente no poço seja carregado pelo gás até o separador. O acúmulo de líquido no poço devido à perda de capacidade do gás em arrastá-lo decorre do próprio envelhecimento do reservatório, mas também da sensibilidade das propriedades dos hidrocarbonetos a variações de pressão e temperatura durante transientes de produção. Desta forma, a redução da quantidade de movimento do gás ascendente gera um escoamento oscilatório do líquido que, ao se acumular no poço, aumenta sua queda de pressão, reduzindo assim, ou até mesmo interrompendo, a produção. A fim de abordar o fenômeno acima descrito, denominado carga de líquido (liquid loading), é necessário compreender a interação entre o poço e a região adjacente do reservatório. Adicionalmente, é necessário possuir ferramentas capazes de resolver o escoamento bifásico no poço em função tanto do espaço quanto do tempo. Embora a literatura seja rica em trabalhos sobre escoamentos gás-líquido em canais ver ticais, estes resultam, em sua maioria, em correlações empíricas ou modelos simplificados para o cálculo da queda de pressão e das frações volumétricas das fases em condições de regime permanente. Mesmo que tais relações sirvam de critério para a ocorrência do fenômeno de liquid loading, elas não possibilitam a descrição da sequência de eventos que levam à transição entre os regimes de escoamento unidirecional ascendente e oscilatório. Este trabalho apresenta um modelo diferencial unidimensional para o cálculo do escoamento gás-líquido transiente em tubos verticais com altas frações de gás (padrões anular e churn). Equações de conservação de natureza hiperbólica para a massa, quantidade de movimento e energia são propostas para as fases gasosa e líquida, a qual é dividida entre os campos de filme contínuo e gotículas arrastadas pelo núcleo de gás. Relações de fechamento para o cálculo do atrito na parede e na interface do filme, além de expressões para as taxas de entranhamento e deposição de gotículas, foram obtidas da literatura. Um algoritmo de solução por diferenças finitas baseado no método da separação da matriz de coeficientes foi implementado a fim de melhor lidar com variações acentuadas no domínio espaço-temporal, tais como ondas de pressão e de retenção de fases. Os resultados do modelo foram comparados com dados experimentais de regime permanente obtidos de oito referências da literatura, somando mais de 1300 pontos para o gradiente de pressão, a vazão do filme de líquido e a retenção gasosa. Para estas variáveis, a concordância entre o modelo e os dados foi em margens inferiores a ± 20%. O modelo foi avaliado também contra dados experimentais para escoamentos gás-líquido transientes em um tubo vertical de 42 m de comprimento e diâmetro de 0,049 m (Waltrich, 2012). Transientes induzidos por variações de pressão e de vazão de líquido na seção de testes foram simulados, conferindo níveis de concordância entre dados experimentais e modelo matemático também inferiores a ± 20%.Abstract : In the production of natural gas, it is essential that all liquids are carried upwards by the flowing gas up to the separator. The accumu- lation of liquid in the well and the decrease in the gas capability to lift the liquid are natural processes associated with the ageing of the reservoir itself, but are also related to sensitivity of the properties of hydrocarbons to pressure and temperature variations during transient production. At a given point, a reduction in the gas momentum gives rise to an oscillatory motion of the liquid, which increases the pressure drop in the well, thereby reducing or even interrupting the production prematurely. To understand the phenomenon of liquid loading described above, it is necessary to understand the interaction between the well and the near wellbore region of the reservoir. Additionally, mathematical tools are needed to solve the two-phase flow of gas and liquid in the time and space domains. Despite the large number of works on gas-liquid flows in vertical channels available in the literature, these are mostly either empirical correlations or simplified models for the calculation of pressure drop and phase fractions at steady state. Although sim- ple relationships serve as criteria for the occurrence of liquid loading, they fail to describe the sequence of events that lead to the transition between the unidirectional and bidirectional (oscillatory) flow regimes. This work presents a one-dimensional differential model for calcu- lating gas-liquid transient flow in vertical tubes with high gas fractions (annular and churn flow patterns). Hyperbolic conservation equations for mass, momentum and energy are proposed for the gas and liquid phases, which is split between a continuous film and droplets entrained in the gas core. Closure relationships to calculate the wall and in- terfacial friction and the rates of droplet entrainment and deposition were obtained from the literature. A finite-difference solution algo- rithm based on the Split Coefficient Matrix Method was implemented to deal with sharp variations in the spatial and temporal domain, such as pressure and phases holdup waves. The model results were com- pared with steady-state experimental data from eight different sources, totaling more than 1300 data points for pressure gradient, liquid film flow rate and gas holdup. For these variables, the agreement between the model and the data was within less than ± 20%. The model was also compared against experimental data for transient gas-liquid flows in a 42-m long, 0.049-m ID vertical tube (WALTRICH, 2012). Pressure and flow rate-induced transients were simulated, with levels of agree- ment between the experimental data and the mathematical model also smaller than ± 20%

Signs In Time: The Hypothesis Of Social Time For A Cultural Semiotic Analysis

http://www.ester.ee/record=b4482490*es

Biodiesel and social inclusion: a fuzzy set and regression analysis in the north of Brazil

After the launch of Brazilian Biodiesel use and production Program (PNPB) in 2004, the oil seed production became an economic alternative for family farmers since they might have the chance to improve their income and supply biodiesel enterprises with raw material. Theoretically speaking this picture is easy to draw, but few recent little scientific research was carried out aiming at identifying the socio-economic profile of farmers that are being included in the Brazilian biodiesel chain. Thus, this study aims to assess the links between the family farmers’ living standards and the adoption of oil seed activity. Thus, an analysis of Jatropha curcas and Ricinus communis small-scale seed production was done in the Tocantins state, located in the north of Brazil. A fuzzy set theory was applied to construct deprivation indicators based on living standard criteria and a nonlinear probit model was formulated to analyze the inclusion of poor families in the biodiesel chain. The preliminary results point towards a positive relationship between degree of deprivation and adoption of oil seed activity in the case of Ricinus communis system production and a negative relationship in the case of Jatropha curcas system

Use of a High-Power Laser for Wound Healing: A Case Report

Introduction: The use of low-level laser therapy (LLLT) to treat wounds and accelerate tissue healing has been extensively studied in recent years. The aim of this article is to describe a clinical case using an unfocused high-power laser instead of a low-power laser for therapy. Case Report: In the present article, we present the use of a high-power diode laser to treat an extensive knee injury that occurred after surgical treatment for total prosthesis due to border ischemia resulting from prolonged use of autostatic retractors. Conclusion: It is possible to use an unfocused high-power laser at a decreased intensity to accelerate healing as an adjuvant in the treatment of complicated wounds. This procedure results in reduced application time and cost and an excellent tissue response pattern similar to that reported in the literature with low-power lasers

Análise exergética experimental de uma unidade de refrigeração por absorção de 5 TR movida a gás liquefeito de petróleo (GLP) e/ou gases de exaustão /

Orientador : José Viriato Coelho VargasCo-orientador : Rudmar Serafim de MatosDissertação (mestrado) - Universidade Federal do Paraná, Setor de Tecnologia, Programa de Pós-Graduação em Engenharia Mecânica. Defesa: Curitiba, 2006Inclui bibliografi

Three Essays on Corporate Finance: Evidence from Brazil

In this study, we use some relatively unique characteristics of the Brazilian stock market to test corporate governance, capital structure, and payout decisions hypotheses. In Chapter One, we find that a composite index (NM6) that proxy for the main governance practices targeted by Bovespa's voluntary reform is statistically and economically related to higher market valuation. We also find that an investment strategy that bought stocks of better governed firms and sold stocks of poorly governed firms would have earned annual abnormal returns of 10.4 between 2001 and 2005. In Chapter Two, we examine how entrenchment is related to capital structure in a market characterized by closely held firms and significant separation between ownership and control. Our results support the hypothesis that entrenched insiders choose less levered capital structures to reduce the probability of bankruptcy or to elude external monitoring by debtholders. In Chapter Three, we examine the relation between firm characteristics and the choice of payout on equity. In Brazil, firms can distribute earnings to shareholders in the form of dividends or notional interest equity. Whereas dividends are not taxed at the personal level, the net tax effect of interest payments is lower because of their deductibility. Our results are consistent with the use of the notional interest on equity because of its tax deductibility despite the personal tax advantage of dividend payments