Unitiza����o de jazidas de petr��leo: uma aplica����o do modelo de Green e Porter

Neste trabalho abordamos a unitiza����o como uma reinterpreta����o de cartel, partindo do modelo cl��ssico de Green e Porter. A incerteza geol��gica �� representada por um componente estoc��stico no custo marginal. Caracterizamos o contrato ��timo e, a partir da est��tica comparativa, avaliamos a efici��ncia e a viabilidade da coopera����o. O pre��o e o grau da externalidade afetam positivamente o n��vel de efici��ncia do contrato ��timo. Mas enquanto pre��os elevados viabilizam os acordos, o grau de externalidade elevado pode conduzir a equil��brios ineficientes ou mesmo inviabilizar a produ����o. O mesmo resultado ocorre com os custos fixos. Adicionalmente, quanto maior for o n��mero de firmas envolvidas no acordo, menor ser�� a chance de existir um contrato mais eficiente que a regra da captura.

Risco idiossincr��tico e diversifica����o em portf��lios

A teoria tradicional de finan��as indica a diversifica����o como uma maneira de tirar a exposi����o que um investidor tem ao risco espec��fico das firmas. Ao investidor caberia a tarefa de construir um portfolio composto de N ativos tal que a parcela de risco idiossincr��tico tenda a zero. Os retornos desta carteira seriam advindos da remunera����o pelo risco sistem��tico, ou de mercado. Estudos t��m mostrado que o N necess��rio para atingir o benef��cio satisfat��rio de diversifica����o tem aumentado ao longo dos anos. O motivo para tal fen��meno seria a presen��a cada vez mais forte da parcela de risco idiossincr��tico, verificado empiricamente atrav��s de estudos das s��ries hist��ricas dos retornos. O risco idiossincr��tico tem estado presente mesmo sem ter havido um crescimento no risco do mercado como um todo. O objetivo deste estudo �� discorrer sobre a literatura dispon��vel acerca do assunto, mostrando como a partir da Modern Portfolio Theory o desafio de alcan��ar a diversifica����o tem sido cada vez mais complexo, como t��m sido feitas as an��lises da presen��a o risco idiossincr��tico e quais motivos levaram isto a acontecer.

Os efeitos da auditoria independente (externa) sobre a manipula����o da informa����o cont��bil por parte das OPS brasileiras

A presente pesquisa busca investigar se a auditoria externa (independente) minimiza a propens��o �� manipula����o das informa����es cont��beis - MIC (medidas pelas acumula����es discricion��rias correntes) por parte das operadoras de plano privado de assist��ncia �� sa��de, no que tange ��s informa����es econ��mico-financeiras divulgadas �� Ag��ncia Nacional de Sa��de Suplementar. Ap��s revis��o bibliogr��fica sobre qualidade da informa����o cont��bil, auditoria e mercado de sa��de suplementar, promoveu-se uma pesquisa emp��rica com informa����es prestadas �� ANS pelas OPS relativas ao per��odo de 2004 a 2006. Para verificar se h�� diferen��a significativa no n��vel de acumula����es discricion��rias correntes, medidas pelo modelo AWCA e Jones Modificado (1995), entre as informa����es auditadas (quarto trimestre de cada ano) e as informa����es n��oauditadas (tr��s primeiros trimestres de cada ano) para as mesmas empresas foi aplicado o teste n��o-param��trico de Mann-Whitney. Os resultados indicam que n��o existem diferen��as estat��sticas significativas na propens��o �� manipula����o entre as informa����es cont��beis auditadas e n��o-auditadas, pelo menos no que tange ��s informa����es de 2004 a 2006 prestadas pelas OPS �� ANS. Adicionalmente, tamb��m foram testadas as influ��ncias do tipo de modalidade, porte da firma e situa����o apresentada do patrim��nio l��quido sobre as acumula����es discricion��rias correntes. Observou-se que essas tr��s vari��veis influenciam em maior ou menor grau na manipula����o da informa����o cont��bil gerada pelas OPS �� ANS. Neste contexto, as seguintes caracter��sticas sobre a maior propens��o a MIC foram diagnosticadas: Cooperativa Odontol��gica e a Medicina de Grupo (Modalidade); Pequeno (Porte da Firma); e Passivo a Descoberto ou PL Pr��ximo de Zero (Situa����o do Patrim��nio L��quido). Ao passo que as caracter��sticas relacionadas �� menor propens��o de MIC foram: Cooperativa M��dica e Filantropia (Modalidade); M��dio e Grande (Porte da Firma); Patrim��nio L��quido Favor��vel (Situa����o do Patrim��nio L��quido).

Uma nova estrat��gia de negocia����o em pares

Uma das principais vantagens das estrat��gias de negocia����o em pares est�� relacionada �� baixa correla����o com os retornos do mercado. Ao tomar posi����es compradas e vendidas, estas estrat��gias s��o capazes de controlar a magnitude do beta de mercado, mantendo-se praticamente zero ou estat��sticamente n��o significativas. A id��ia consiste na realiza����o de arbitragem estat��stica, aproveitando os desvios de pre��os de equil��brio de longo prazo. Como tal, elas envolvem modelos de corre����o de equil��brio para os pares de retornos dos ativos. N��s mostramos como construir uma estrat��gia de negocia����o de pares que �� beneficiada n��o s�� pela rela����o de equil��brio de longo prazo entre os pares de pre��os dos ativos da carteira, mas tamb��m pela velocidade com que os pre��os ajustam os desvios para o equil��brio. At�� ent��o, a grande maioria das estrat��gias envolvendo negocia����o em pares se baseavam na hip��tese de que a obten����o de retornos positivos estaria relacionada �� revers��o �� m��dia caracterizada pela rela����o de cointegra����o dos pares, mas ignorava a possibilidade de sele����o dos pares testando a velocidade de ajustamento do Vetor de Corre����o de Erros desta rela����o. Os resutados deste trabalho indicaram baixos n��veis de correla����o com o mercado, neutralidade das estrat��gias, associados a retornos financeiros l��quidos e ��ndice de Sharpe anualizados de 15,05% e 1,96 respectivamente.

A tributa����o como um dos instrumentos �� sustentabilidade ambiental

A presente monografia versa sobre o papel da tributa����o como instrumento da sustentabilidade ambiental. Para tanto, utiliza-se como exemplo, a contr��rio senso, o Conv��nio CONFAZ n��.100/97, que reduz a zero a base de c��lculo do Imposto sobre Circula����o de Mercadorias e Presta����o de Servi��os Interestaduais e Intermunicipais e de Comunica����es (ICMS) nas sa��das dos defensivos agr��colas. Posteriormente, analisa-se brevemente o poder de tributar e suas limita����es, bem como o benef��cio fiscal do ICMS, e em especial, do Conv��nio CONFAZ supracitado. Por fim, examina-se a sustentabilidade sob o vi��s jur��dico, econ��mico e sist��mico, em cotejo com a tributa����o no contexto da sustentabilidade ambiental.

"Desesperan��a de vida: homic��dio em Minas Gerais , Rio de Janeiro e S��o Paulo: 1981 a 1997"

This paper studies the male homicide rate and its relation to economic variables in the states of Minas Gerais, S��o Paulo e Rio de Janeiro between 1981 and 1997. The novelty of our approach is the construction of homicide rates specific for each age between 15 and 40 years old. The economic variables' coefficients are significant1y different from zero for the population between 15 and 19 years old. As expected, an increase in real wage and a decrease in inequality reduce the rate of homicide. Surprisingly, a decrease in the unemployment rate seems to increase the rate ofhomicide. Most coefficients, however, converge to zero as a generation gets older, becoming non-significant for the population aged 20 years old or more. We also identify an inertia component in the homicide rate: generations with higher homicide rates when young also tend to have higher homicide rates over the remain of their life cycle. Therefore, if economic variables induce a high rate of homicide among young people in a certain year, this high rate tend to persist over the generation life cycle independent1y of the economy later behavior. Regressions are performed using a reformulation of the standard Logit model that incorporates a lagged dependent variable.

The impact on the stationary state income of a pay-as-you-go system of social security

A model of overlapping generations in continuous time is composed. IndividuaIs pass through two distinct time periods during their life times. During the first period, they work, save and have a death probability equal to zero. During the second, from the periods T after birth, their probability of death changes to p and then they retire. Capital stock and the stationary state in come are calculated for two situations: in the first, people live from their accumulated capital after retirementj in the second, they live from a state transfer payment through income taxo To simplify matters, in this preliminary version, it is supposed that there is no population growth and that the instantaneous elasticity substitution of consumption is unitary.

Similarity between the in vitro activity and toxicity of two different fungizone��� / lipofundin��� admixtures

Amphotericin B (AmB), an antifungal agent that presents a broad spectrum of activity, remains the gold standard in the antifungal therapy. However, sometimes the high level of toxicity forbids its clinical use. The aim of this work was to evaluate and compare the efficacy and toxicity in vitro of Fungizon��� (AmB-D) and two new different AmB formulations. Methods: three products were studied: Fungizon���, and two Fungizon��� /Lipofundin��� admixtures, which were diluted through two methods: in the first one, Fungizon��� was previously diluted with water for injection and then, in Lipofundin��� (AmB-DAL); the second method consisted of a primary dilution of AmB-D as a powder in the referred emulsion (AmB-DL). For the in vitro assay, two cell models were used: Red Blood Cells (RBC) from human donors and Candida tropicallis (Ct). The in vitro evaluation (K+ leakage, hemoglobin leakage and cell survival rate-CSR) was performed at four AmB concentrations (from 50 to 0.05mg.L-1). Results: The results showed that the action of AmB was not only concentration dependent, but also cellular type and vehicle kind dependent. At AmB concentrations of 50 mg.L-1, although the hemoglobin leakage for AmB-D was almost complete (99.51), for AmB-DAL and AmB-DL this value tended to zero. The p = 0.000 showed that AmB-D was significantly more hemolytic. Conclusion: The Fungizon���- Lipofundin��� admixtures seem to be the more valuable AmB carrier systems due to their best therapeutic index presented

Estudo sobre a influ��ncia do massar�� no processo de forma����o de salitre em rebocos na regi��o de Teresina - PI

This work had to verify the influence of massar��, while mortar component, in the process of formation of saltpeter in cementitious plaster walls of buildings. The massar�� is a ceramic material, texture areno usually found in large volumes argillaceous sediments in Teresina, Piaui State capital, which is associated with the Portland cement mortar form for fixing and finishing in construction. Saltpeter or flowering is a pathology that happens in gypsum wallboard, which invariably reaction between soluble salts present in materials, water and oxygen. This pathology, supposedly credited to massar�� caused its use to suffer significant reduction in the market of the buildings. Verify this situation with particular scientific rigor is part of the proposal of this work. Grading tests Were performed, consistency limits (LL, LP and IP), determination of potential hydrogen, capacity Exchange (CTC), electrical conductivity (EC), x-ray fluorescence (FRX) and x-ray diffraction (DRX). Massar�� analysed samples in number six, including sample plastering salitrado presented potential hydrogen medium 5.7 in water and 5.2 on KCl n and electrical conductivity (EC), equal to zero. These results pointed to the affirmative that massar�� is a material that does not provide salinity content that can be taken into consideration. It is therefore concluded that the material analyzed not competing, at least with respect to the presence of soluble salts, for the formation of saltpeter

Avalia����o de produtos naturais no controle de biofilmes formados em sistema din��mico

The biofilms microbial forms of association are responsible for generating, accelerating and / or induce the process of corrosion. The damage generated in the petroleum industry for this type of corrosion is significatives, representing major investment for your control. The aim of this study was to evaluate such tests antibiograms the effects of extracts of Jatropha curcas and essential oil of Lippia gracilis Schauer on microrganisms isolated from water samples and, thereafter, select the most effective natural product for further evaluation of biofilms formed in dynamic system. Extracts of J. curcas were not efficient on the complete inhibition of microbial growth in tests type antibiogram, and essential oil of L. gracilis Schauer most effective and determined for the other tests. A standard concentration of essential oil of 20 μL was chosen and established for the evaluation of the biofilms and the rate of corrosion. The biocide effect was determined by microbial counts of five types of microorganisms: aerobic bacteria, precipitating iron, total anaerobic, sulphate reducers (BRS) and fungi. The rate of corrosion was measured by loss of mass. Molecular identification and scanning electron microscopy (SEM) were performed. The data showed reduction to zero of the most probable number (MPN) of bacteria precipitating iron and BRS from 115 and 113 minutes of contact, respectively. There was also inhibited in fungi, reducing to zero the rate of colony-forming units (CFU) from 74 minutes of exposure. However, for aerobic and anaerobic bacteria there was no significant difference in the time of exposure to the essential oil, remaining constant. The rate of corrosion was also influenced by the presence of oil. The essential oil of L. gracilis was shown to be potentially effective

An��lise in vitro da atividade antif��ngica e de toxicidade da anfotericina B pr��-aquecida

The aim of this work was to evaluate how an aqueous micellar system containing Amphotericin B (AmB) and sodium deoxycholate (DOC) can be rebuilt after heating treatment. Also a review of the literature about the new physicochemical and biological properties of this new system was carried out. Afterwards, heated (AmB-DOC-H) and unheated (AmB-DOC) micelles were subsequently diluted at four different concentrations (50mg.L-1, 5mg.L-1, 0.5mg.L-1 and 0.05mg.L-1) to perform the physicochemical study and, then, the pharmacotoxicity assay, in which two cell models were used for the in vitro experiments, Red Blood Cells (RBC) from human donors and Candida parapisilosis (Cp). While potassium (K+) and hemoglobin leakage from RBC were the used parameters to evaluate the acute and chronic toxicity, respectively, the efficacy of AmB-DOC and AmB-DOC-H were assessed by K+ leakage and cell survival rate from Cp. The spectral study revealed a slight change on the aggregate peak from 327nm to 323nm for AmB-DOC-H compared to AmB-DOC. Concerning the toxicity, although AmB-DOC and AmB-DOC-H presented different behavior for hemoglobin leakage, AmB-DOC produced higher leakage than AmB-DOC-H at high concentrations (from 5mg.L-1) with values tending to zero. However, concerning K+ leakage, both AmB-DOC and AmB-DOC-H, showed similar profile for both cell models, RBC and Cp (p<0,05). AmB-DOC-H and AmB-DOC also revealed similar profile of activity against Cp with equivalent survival rate. In short, the AmB-DOC-H showed much less toxicity than AmB-DOC, but remained as active as the late one against fungal cell. Therefore, the results highlight the importance of this new procedure as a simple, inexpensive and safe alternative to produce a new kind of micelle system for treatment of systemic fungal infections

Correla����es gen��ticas e fenot��picas em duas popula����es de milho (Zea mays L.) braqu��tico e suas implica����es no melhoramento do teor de ��leo no gr��o

Coeficientes de correla����es gen��ticas e fenot��picas foram estimados entre os caracteres: altura da planta (AP); altura da espiga (AE); peso de espigas (PE) e teor de ��leo (TO). As estimativas foram obtidas para duas popula����es braqu��ticas de milho (Piran��o VD-2 e Piran��o VF-1), baseado em espiga por fileira, utilizando-se testemunha intercalar, onde a cada duas prog��nies plantava-se uma fileira do h��brido simples AG 305-B. Os valores das correla����es gen��ticas aditivas encontradas entre os caracteres altura da planta, altura da espiga e peso de espigas, foram todos positivos. Para o car��ter teor de ��leo, quando correlacionado com os demais caracteres, os valores das correla����es obtidos foram negativos nas duas popula����es, exce����o feita ao peso de espiga correlacionada com teor de ��leo, na popula����o Piran��o VD-2, cujo valor foi positivo e pr��ximo de zero. As respostas correlacionadas obtidas entre os caracteres, quando a sele����o �� praticada para o car��ter teor de ��leo e vice versa, independente do m��todo de sele����o empregado, mostram que a sele����o para teor de ��leo leva a modifica����o na estrutura da planta, para as duas popula����es.

Estimativa da ��rea foliar de crotalaria juncea l. a partir de dimens��es lineares do limbo foliar

Knowledge of the leaf area plant are needed for agronomic and physiological studies involving plant growth. The aim of this study was to obtain a mathematical model using linear measures of leaf dimensions, which will allow the estimation of leaf area of Crotalaria juncea L. Correlation studies were conducted involving real leaf area (Sf) and leaf length (C), maximum leaf width (L) and the product between C and L. All tested models (linear, exponential or geometric) provided good estimation of leaf area (above 87%). The better fit was attained using linear model, passing or not through the origin. From a practical viewpoint, it is suggested to use the linear model involving the C and L product, using a linear coefficient equal to zero. Estimation of leaf area of Crotalaria juncea L. can be obtained using the model Sf = 0.7160 x (C*L) with a determination coefficient of 0.9712.

Estimativa da ��rea foliar de Ageratum conyzoides usando dimens��es lineares do limbo foliar

The aim of this research was to obtain a mathematical equation to estimate the leaf area of Ageratum conyzoides based on linear measures of its leaf blade. Correlation studies were done using real leaf area (Sf), leaf length (C) and the maximum leaf width (L), in about 200 leaf blades. The evaluated statistic models were: linear Y = a + bx; simple linear Y = bx; geometric Y = ax(b); and exponential Y = ab(x). The evaluated linear, exponential and geometric models can be used in the billygoat weed leaf area estimation. In the practical sense, the simple linear regression model is suggested using the C*L multiplication product and taking the linear coefficient equal to zero, because it showed weak-alteration on sum of squares error and satisfactory residual analysis. Thus, an estimate of A conyzoides leaf area can be obtained using the equation Sf = 0.6789*(C*L), with a determination coefficient of 0.8630.

Monotonicity and asymptotics of zeros of Sobolev type orthogonal polynomials: A general case

Coordena����o de Aperfei��oamento de Pessoal de N��vel Superior (CAPES)