Avaliação das Opções Reais de Conversão e Abandono para Uma Mineradora de Minério de Ferro Sob Cenário de Stress

O mercado de minério de ferro tem passado por um período de stress nos últimos meses. O arrefecimento dos investimentos chineses em infraestrutura resultou em perspectivas negativas para a demanda dessa commodity. Paralelamente, a entrada em operação de novos projetos com volume de produção relevante aumentou a oferta desse produto no mercado. Essa conjuntura de fatores resultou na queda do preço do minério de ferro no mercado mundial e em um cenário de retornos reduzidos para as mineradoras. Nesse contexto, o objetivo do presente estudo é avaliar a flexibilidade gerencial, disponível aos administradores de mineradoras operacionais, de suspender ou fechar o empreendimento dependendo do preço do minério de ferro. Essas decisões serão estudadas através da Teoria das Opções Reais, onde a opção de conversão será aplicada na situação de suspensão e reabertura da mina e a opção de abandono será aplicada na situação do seu fechamento. O processo estocástico a ser seguido pelo preço do minério de ferro será o Movimento Geométrico Browniano, implementado através de um Modelo Binomial conforme proposto por Cox, Ross e Rubinstein (1979). O resultado do trabalho comprova o valor das opções reais estudadas e indica que essas opções reais têm maior valor em cenários de stress, quando o preço do minério de ferro está desvalorizado.

Discursos na internet expõem polarização sobre arrastões

A análise dos discursos sobre os arrastões, expostos nas redes sociais ao longo da semana, traz à tona talvez aquela que seja a principal característica dos debates políticos em curso no Brasil: a polarização. Levantamento da Diretoria de Análise de Políticas Públicas (DAPP) da FGV aponta o predomínio de dois grupos distintos: os “defensores da ordem”, que apoiam o endurecimento da ação policial e, em alguns casos, aprovam a ação de justiceiros; e os críticos às forças policiais, que classificam a ação do Estado como preconceituosa e, em determinadas situações, relativizam as ações criminosas sob a ótica da injustiça social.

Polarização perde espaço em rede social

Estudo da DAPP sugere redução das polarizações anti e pró-governo nas redes sociais durante os protestos do 13M.

Conversão térmica e termocatalítica à baixa temperatura do óleo de girassol para obtenção de bio-óleo

The use of biofuels remotes to the eighteenth century, when Rudolf Diesel made the first trials using peanut oil as fuel in a compression ignition engine. Based on these trials, there was the need for some chemical change to vegetable oil. Among these chemical transformations, we can mention the cracking and transesterification. This work aims at conducting a study using the thermocatalytic and thermal cracking of sunflower oil, using the Al-MCM-41 catalyst. The material type mesoporous Al-MCM-41 was synthesized and characterized by Hydrothermical methods of X-ray diffraction, scanning electron microscopy, nitrogen adsorption, absorption spectroscopy in the infrared and thermal gravimetric analysis (TG / DTG).The study was conducted on the thermogravimetric behavior of sunflower oil on the mesoporous catalyst cited. Activation energy, conversion, and oil degradation as a function of temperature were estimated based on the integral curves of thermogravimetric analysis and the kinetic method of Vyazovkin. The mesoporous material Al-MCM-41 showed one-dimensional hexagonal formation. The study of the kinetic behavior of sunflower oil with the catalyst showed a lower activation energy against the activation energy of pure sunflower oil. Two liquid fractions of sunflower oil were obtained, both in thermal and thermocatalytic pyrolisis. The first fraction obtained was called bio-oil and the second fraction obtained was called acid fraction. The acid fraction collected, in thermal and thermocatalytic pyrolisis, showed very high level of acidity, which is why it was called acid fraction. The first fraction was collected bio-called because it presented results in the range similar to petroleum diesel

Determinação da idade dental de crianças brasileiras nordestinas: novos valores de conversão de maturidade dental para população específica

Since Demirjian's system of estimating dental maturity was first described, many researchers from different countries have tested its accuracy among diverse populations. Some of these studies have pointed out a need to determine population-specific standards. In Brazil, the Northeast region is the one that most suffers the negative impact of exodus, specially related to the increase of abandoned children in the cities. The aim of this study was to test the accuracy of Demirjian's system for assessing the dental maturity of northeastern Brazilian children, so as to present a scale for maturity score conversion into dental age developed specifically for this population. This could be used for forensic, anthropological and legal matters, and also as a model for other countries attempting to formulate their own conversion scales. Panoramic radiographs of 1,491 children (821 females and 670 males), aged 7 to 13 years, from Ceará state, northeast Brazil, were assessed by a single observer to determine dental age (DA) according to Demirjian's system. The mean percentage of intra-observer agreement was 86.6%, with a mean Cohen's Kappa coefficient of 0.67 (substantial agreement). The DA was compared by paired t-test to subjects' chronological age (CA). The differences between CA and DA in all age groups were statistically significant (p<0.0001), demonstrating a great advancement in DA among Brazilians. Scatter plots were drawn for both genders, and the data were fitted to a growth curve, y = 100/ (1 + e-a(x b)). Graphs corresponding to the 50th percentile curves were produced. A table with new values for the conversion of maturity score into dental age for northeastern Brazilian children is presented. The great advancement in DA, as obtained by Demirjian's system in this population, justified the determination of specific scores for dental maturity assessment

Os filhos evangélicos do novo caldeirão do diabo: a conversão religiosa na penitenciária de alcaçuz

The theme of the research is inserted at a field of intersection between the Sociology of Religion and Sociology of Violence, having as the general objective study the sociological meaning of the conversion of prisoners that lives at the biggest prison (Prison of Alcaçuz) of Rio Grande do Norte to the evangelical churches. The research is justified, because Brazil shelter the fourth greater arrested population arrested of the world, with projections indicating that it can turn the greatest in 2034. Besides, this study about religious conversion of prisoners to the Social Sciences is too important, because is a theme little developed in Brazil and deserves attention, one time that as the arrested people as the evangelicals are in expansion in our country. Starting from the precedent observations, we guide ourselves by the following problematic of research: the religious practice in Alcaçuz presents a mere instrumental perspective, where the actions of prisoners converted was on purpose oriented to conquest material or symbolic privileges; or purely religious, where seek a moral renovation? To develop the work, the scientific methodology adopted was exploratory and explanatory, using the Goffman´s theory about total institutions and presentation of self, and Blumer´s doctrine relating to Symbolic Interacionism and the Story life method, besides considerations about evangelical religion. Having this theoretical basis, was accomplished the Field research, when were made interviews and applied questionnaires to 11 Jailer Agents, 31 prisoners, Director and Vice-Dictor (in November, 2011), the coordinator of social projects of the prison and the coordinator of evangelization at the prisons in Rio Grande do Norte. As results, it was seeing in Alcaçuz that the prisoners can be separated in two groups: the one of Pavilions and other one of the Medical Section. The Pavilions are branded for managerial and structural problems, where are found idle prisoners in collective cells and with a historical of escaping attempts, mutinies and murders. The Medical Section has some individual cells or destined for two people, besides few collective also, and the prisoners work and have a more disciplined behavior, there isn t escapes or rebellions and that, for these reasons end for have more confidence from the Administration. About the presence of evangelical prisoners, most are at Medical Section, where exist a specific place to the cults (what doesn t at Pavilions). At the end, the conclusion is that the prisoner that says himself evangelical in Alcaçuz, although can be seeing with distrust about your real conversion, he gets win a trust vote and until the opposite being demonstrated in other words, that he is not hiding himself behind the bible to divert the vigilance of Direction and practice disciplinary faults without make any suspicions, is treated with more respect and has more opportunities live at Medical Section; have work, that most of times is paid and guarantee the homologation of your payment of penalty with work, besides other benefits, diminishing his time in jail

Validação interlaboratorial do teste de polarização fluorescente para o diagnóstico sorológico da brucelose bovina

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

Conversão do metano via oxicloração em reator de leito fixo utilizando catalisador do tipo CuCl2/SiO2

Supported catalysts of CuCl2 on sílica were used in the methane oxychlorination reaction. The materials were synthesized by the ion exchange technique in a basic solution, using a copper-ammonia complex with 3 and 6 % of nominal copper loading. The materials where characterized by thermogravimetry (TG), X-ray Fluorescence Spectroscopy (XRF), Temperature Programmed Reduction (TPR), Scanning Electron Microscopy with X-ray microanalysis (SEM/EDS), BET specific area and pore distribution. The characterization confirms the presence of copper on the support surface, concluding that the ion exchange technique was adequate in the catalyst synthesis. For the reaction test, an oxychlorination bench scale unit was employed. The tests were carried at 673 and 773 K. The results showed the influence of temperature and catalyst copper content on the oxychlorination of methane reaction

Conversão catalítica de clorometano em hidrocarbonetos

Amorphous silica-alumina and modified by incipient impregnation of iron, nickel, zinc and chromium were synthetized in oxide and metal state and evaluated as catalysts for the chloromethane conversion reaction. With known techniques their textural properties were determined and dynamics techniques in programmed temperature were used to find the acid properties of the materials. A thermodynamic model was used to determine the adsorption and desorption capacity of chloromethane. Two types of reactions were studied. Firstly the chloromethane was catalytically converted to hydrocarbons (T = 300 450 oC e m = 300 mg) in a fixed bed reactor with controlled pressure and flow. Secondly the deactivation of the unmodified support was studied (at 300 °C and m=250 g) in a micro-adsorver provided of gravimetric monitoring. The metal content (2,5%) and the chloromethane percent of the reagent mixture (10% chloromethane in nitrogen) were fixed for all the tests. From the results the chloromethane conversion and selectivity of the gaseous products (H2, CH4, C3 and C4) were determined as well as the energy of desorption (75,2 KJ/mol for Ni/Al2O3-SiO2 to 684 KJ/mol for the Zn/Al2O3-SiO2 catalyst) considering the desorption rate as a temperature function. The presence of a metal on the support showed to have an important significance in the chloromethane condensation. The oxide class catalyst presented a better performance toward the production of hydrocarbons. Especial mention to the ZnO/Al2O3-SiO2 that, in a gas phase basis, produced C3 83 % max. and C4 63% max., respectively, in the temperature of 450 oC and 20 hours on stream. Hydrogen was produced exclusively in the FeO/Al2O3-SiO2 catalysts (15 % max., T = 550 oC and 5,6 h on stream) and Ni/SiO2-Al2O3 (75 % max., T = 400 oC and 21,6 h on stream). All the catalysts produced methane (10 à 92 %), except for Ni/Al2O3-SiO2 and CrO/Al2O3-SiO2. In the deactivation study two models were proposed: The parallel model, where the product production competes with coke formation; and the sequential model, where the coke formation competes with the product desorption dessorption step. With the mass balance equations and the mechanism proposed six parameters were determined. Two kinetic parameters: the hydrocarbon formation constant, 8,46 10-4 min-1, the coke formation, 1,46 10-1 min-1; three thermodynamic constants (the global, 0,003, the chloromethane adsorption 0,417 bar-1, the hydrocarbon adsorption 2,266 bar-1), and the activity exponent of the coke formation (1,516). The model was reasonable well fitted and presented a satisfactory behavior in relation with the proposed mechanism

A incorporação da saúde bucal no programa saúde da família do Rio Grande do Norte: investigando a possibilidade de conversão do modelo assistencial

The Health Family Program (HFP) was founded in the 1990s with the objective of changing the health care model through a restructuring of primary care. Oral health was officially incorporated into HFP mainly through the efforts of dental professionals, and was seen as a way to break from oral health care models based on curative, technical biological and inequity methods. Despite the fast expansion of HFP oral health teams, it is essential to ask if changes are really occurring in the oral health model of municipalities. Therefore, the purpose of this study is to evaluate the incorporation of oral health teams into the Health Family Program by analyzing the factors that may interfere positively or negatively in the implementation of this strategy and consequently in the process of changing oral health care models in the National Health System in the state of Rio Grande do Norte, Brazil. This evaluation involves three dimensions: access, work organization and strategies of planning. For this purpose,19 municipalities, geographically distributed according to Regional Public Health Units (RPHU), were randomly selected. The data collection instruments used were: structured interview of supervisors and dentists, structured observation, documental research and data from national health data banks. It was possible to identify critical points that may be impeding the implementation of oral health into HFP, such as, low incomes, no legal employment contract, difficulty in referring patients for high-complexity procedures, in developing intersectoral actions and program strategies such as epidemiologic diagnosis and evaluation of the new actions. The majority of municipalities showed little or no improvement in oral health care after incorporating the new model into HFP. All of them had failures in most of the aspects mentioned above. Furthermore, these municipalities are similar in other areas, such as low educational levels in children from 7 to 14 years of age, high child mortality rates and wide social inequalities. On the other hand, the five municipalities that had improved oral health, according to the categories analyzed, offered better living conditions to the population, with higher life expectancy, low infant mortality rates, per capita income among the highest in the state as well as high Human Development Index (HDI) means. Therefore, it is possible to conclude that public policies that include aspects beyond the health sector are decisive for a real change in health care models

Caracterização e estudo da corrosão do amálgama dentário Dispersalloy por meio das técnicas de polarização potenciodinâmica e espectroscopia de impedância

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

Efeitos da inibição prolongada da enzima de conversão da angiotensina sobre as características morfológicas e funcionais da hipertrofia ventricular esquerda em ratos com sobrecarga pressórica persistente

OBJETIVO: Avaliar os efeitos do lisinopril (L) sobre as taxas de mortes (M), insuficiência cardíaca (ICC), características da remodelação miocárdica, geométrica e funcional do ventrículo esquerdo (VE), em ratos com estenose aórtica supravalvar (EAS). MÉTODOS: Ratos foram submetidos a EAS ou cirurgia simulada (GC:n=10). Randomizados após 6 semanas para receber L (GL:n=30) ou nenhum tratamento (GE:n=73) sendo avaliados 6s e 21s por estudos ecocardiográfico, hemodinâmico e morfológico concomitantes. RESULTADOS: As taxas de M (GE: 53,9% vs GL: 16,7% e ICC GE: 44,8% vs GL: 20% p<0,05). No final do experimento, os valores da pressão sistólica do VE dos grupos GE e GL foram equivalentes e significantemente mais elevados do que no grupo GC; (p<0,05) não diferindo dos observados 6 semanas após os procedimentos cirúrgicos. Os valores da pressão diastólica do VE no grupo GE foram maiores do que os do grupo GL (p<0,05) sendo ambos maiores do que os do grupo GC (4 ± 2 mmHg, p<0,05). O mesmo comportamento foi observado com as variáveis: razão E/A; índice de massa, área seccional dos miócitos e conteúdo de hidroxiprolina do VE. A porcentagem de encurtamento do VE foi semelhante nos grupos GC e GL (p>0,05) sendo ambos maiores que os verificados no grupo GE. Comportamento semelhante foram obtidos com os valores da primeira derivada positiva e negativa da pressão do VE. CONCLUSÃO: em ratos com EAS o L reduziu as taxas de M e ICC e exerceu efeitos benéficos sobre a remodelação e a função do VE.

Hidrelétricas na Amazônia: renovabilidade e não renovabilidade da política energética. Se é desejável a renovabilidade das formas de conversão de energia, por que não é desejável renovar a política energética?

O ensaio tem a intenção de discutir, apresentando como pano de fundo os recentes projetos hidrelétricos propostos e em andamento na Amazônia brasileira, aspectos referentes aos processos de licenciamento ambiental, problemas conceituais que dizem respeito à caracterização da conversão hidrelétrica como energia limpa e renovável. Este trabalho parte da análise de planos governamentais e das discussões sobre projetos hidrelétricos, identificando a necessidade de implementar mudanças institucionais e de fortalecer as leis ambientais e de proteção dos direitos de populações tradicionais e indígenas. Propõe-se uma nova maneira de formular problemas energéticos e de planejar a oferta de energia, que leva em consideração aspectos sustentáveis e patrocinadores da discussão pública, além do entendimento e da incorporação das consequências sobre os grandes ciclos biogeoquímicos que dão suporte às conversões de energia.

Aplicação do método de Polarização Induzida em área de disposição de resíduos sólidos no município de Caçapava do Sul - RS

A geofísica é um método eficaz para investigação de áreas impactadas pelos mais diversos tipos de contaminantes, principalmente em locais de disposição de resíduos sólidos domiciliares e também utilizada na caracterização de contrastes de propriedades físicas em presença de substâncias poluentes. Este trabalho utilizou o método de Polarização Induzida numa área de disposição de resíduos sólidos desativada, localizada no município de Caçapava do Sul - RS. O aterro está assentado sobre rochas metamórficas fraturadas, pertencentes ao Complexo Metamórfico Vacacaí (Neoproterozóico). Foram realizadas 8 linhas de caminhamento elétrico, com espaçamento de 5 m entre eletrodos e 10 níveis de investigação, além de 83 medidas de direção e sentido de fraturas. O resultado geofísico permite caracterizar a camada de resíduos por baixos valores de cargabilidade. Anomalias verticais abaixo da camada de resíduos são interpretadas como zonas de fratura com possível acúmulo de chorume, caracterizadas por baixos valores de cargabilidade.