Soluções para problemas de dispersão e escoamento com condições de contornos curvilíneos por transformações difeomorfas conformes

Neste trabalho, propomos resolver problemas de dispersão e de escoamento definidos em domínios curvilíneos utilizando transformações difeomorfas conformes de coordenadas. Grande parte dos métodos de resolução de equações diferenciais parciais possuem como pré-requisito que o problema original seja definido sobre um domínio de planos paralelos. Métodos de resolução analíticos, semi-analíticos e numéricos são desenvolvidos a partir de domínios simples. Quando aplicados em domínios complexos, naturalmente, surgem dificuldades que são manifestadas essencialmente nos contornos do domínio. Independente do método de resolução, propomos definir uma transformação que altere o sistema de coordenadas original para um sistema de coordenadas curvilíneas equivalente. A transformação deve alterar o sistema de coordenadas original de forma que o domínio curvilíneo seja transformado em um domínio retangular equivalente no novo sistema de coordenadas (sistema de coordenadas curvilíneas). Para este fim, a transformação é construída utilizando informações adquiras pelos contornos curvilíneos A transformação é aplicada sobre as coordenadas, porém ela é invariante e altera também as equações diferenciais parciais que modelam o problema. Inevitavelmente, as equações diferenciais parciais transformadas se tornam mais extensas devido à inserção de novos termos gerados pela relação que existe entre ambos sistemas de coordenadas, chamada de conexão afim. Apesar deste fato, a resolução não se torna mais complexa, apenas mais trabalhosa. A solução obtida deve ser recuperada pela inversão da transformação. Para contextualizar a metodologia, neste trabalho utilizamos a equação de advecção-difusão e as equações de Navier-Stokes acopladas a equação de Poisson para a pressão. Em ambos os casos, as equações são resolvidas numericamente pelo método de diferenças finitas implícito nos casos bidimensional e tridimensional.In this work, we propose to solve problems of dispersion and flow defined in curvilinear domains using diffeomorph conformal transformations of coordinates. Most of the methods of solving partial differential equations have the prerequisite that the original problem be defined on a domain of parallel planes. Analytical, semi-analytical and numerical resolution methods are developed from simple domains. When applied in complex domains difficulties arise which are manifested essentially in the contours of the domain. Regardless of the resolution method, we propose to define a transformation that changes the original coordinate system to an equivalent curvilinear coordinate system. The transformation must change the original coordinate system so that the curvilinear domain is transformed into an equivalent rectangular domain in the new coordinate system (curvilinear coordinate system). To this end, the transformation is constructed using information acquired by the curvilinear contours. The transformation is applied on the coordinates, but it is invariant and also changes the partial differential equations that model the problem. Inevitably, the partial differential equations transformed become more extensive due to the insertion of new terms generated by the affine connection that relates both coordinate systems. Despite this fact, the resolution does not become more complex, just more laborious. The solution obtained must be recovered by reversing the transformation. To contextualize the methodology, in this work we use the advection-diffusion equation and the Navier-Stokes equations coupled to the Poisson equation for the pressure. In both cases, the equations are solved numerically by the finite difference method implicit in two-dimensional and three-dimensional cases

Avaliação dos mecanismos envolvidos na toxicidade de oligômeros do peptídeo β-amiloide em cultura organotípica de hipocampo de ratos

A doença de Alzheimer é a principal e a mais comum desordem neurodegenerativa relacionada à idade. O número de pessoas afetadas pela doença de Alzheimer vem crescendo bastante nos últimos anos, principalmente devido ao aumento da expectativa de vida da população. As causas para o desenvolvimento da doença de Alzheimer são bastante complexas, envolvendo uma combinação de fatores genéticos, moleculares e ambientais. Os emaranhados neurofibrilares, constituídos pela proteína tau hiperfosforilada, e as placas senis, compostas pelo peptídeo β-amiloide, são as duas principais alterações fisiopatológicas encontradas nessa patologia. Existe uma ampla variedade de evidências genéticas, fisiológicas e bioquímicas que suportam a ideia que o peptídeo β-amiloide é ao menos uma das causas que originam a doença de Alzheimer. Na forma monomérica, o peptídeo β-amiloide parece não exercer efeitos tóxicos. Porém, conforme estas formas monoméricas se polimerizam formando intermediários solúveis denominados oligômeros, e por fim protofibrilas e fibrilas, exercem consideráveis efeitos neurotóxicos. Os oligômeros do peptídeo β-amiloide são capazes de se correlacionar de forma mais consistente com os distúrbios cognitivos observados na doença de Alzheimer. Além disso, diversos trabalhos atribuem às alterações sinápticas um dos principais mecanismos de toxicidade dos oligômeros do peptídeo β- amiloide. Para isso, diversas vias de sinalização sofrem alteração no seu funcionamento, como a via das MAPKs, destacando as proteínas JNK1/2 e ERK1/2, e a via Wnt/β-catenina. Neste trabalho nós procuramos avaliar os mecanismos moleculares de toxicidade dos oligômeros do peptídeo β-amiloide em culturas organotípicas de hipocampo de ratos. Para isso, as culturas foram expostas às concentrações de 0,5; 1 e 2 μM por um período de 48h. A morte celular foi avaliada a partir da incorporação do iodeto de propídeo, um marcador de morte celular de células principalmente em processo de necrose. A exposição das culturas a todas as concentrações testadas não foi capaz de causar um aumento significativo na morte celular. Entretanto, observamos um decréscimo nos níveis da proteína sinaptofisina por Western blotting em todas as concentrações utilizadas. Essas alterações nos níveis de sinaptofisina foram acompanhadas pela ativação da proteína JNK, ou seja, pelo aumento da sua fosforilação, e pela inibição da proteína ERK, que teve seus níveis de fosforilação diminuídos. Nós também observamos uma diminuição no imunoconteúdo da proteína β-catenina. A avaliação dos níveis de fosforilação da GSK-3β e β-catenina não apresentou resultado significativo. Embora mais estudos sejam necessários para avaliar os mecanismos de toxicidade dos oligômeros do peptídeo β-amiloide, nossos resultados sugerem uma perda sináptica nas culturas organotípicas, uma das primeiras características observadas na doença de Alzheimer. Acreditamos que esse modelo possa ser utilizado no estudo de fatores fisiológicos e compostos farmacológicos relacionados com a doença de Alzheimer.Alzheimer’s disease is the principal and the most common neurodegenerative age-related disorder. The number of patients affected by Alzheimer’s disease has increased greatly in recent years, mainly due to increase in life expectancy of the population. The causes for the development of Alzheimer’s disease are quite complex, involving a combination of genetics, molecular, and environmental factors. Neurofibrillary tangles, formed by hyperphosphorylated tau protein, and senile plaques, composed of amyloid-β peptide, are the two major pathological changes found in Alzheimer’s disease. A wide variety of genetic, physiological, and biochemical evidences support the idea that amyloid-β peptide is at least one of the main causes of Alzheimer’s disease. In monomeric form the amyloid-β peptide appears did not exert toxic effects. However, as these monomers polymerize forming soluble intermediates called oligomers, and after protofibrils and fibrils, exert considerable neurotoxic effects. The amyloid-β oligomers peptide are more consistently correlated to cognitive disturbances observed in Alzheimer’s disease. In addition, several works have attributed to synaptic changes a major mechanism of amyloid-β oligomers toxicity. Several signaling pathways become altered in their work due to amyloid-β oligomers, such as MAPK pathway, highlighting JNK1/2 and ERK1/2 proteins, and Wnt/β-catenina. In this work, we evaluated the molecular mechanisms of amyloid-β oligomers toxicity in rat organotypic hippocampal slice cultures. For this purpose, cultures were exposed to concentrations of 0.5, 1, and 2 μM of amyloid-β oligomers for 48h. Cell death was assessed from the incorporation of propidium iodide, a marker of cell that are mainly in the necrosis process death. Exposure of all concentrations tested was not able to induce a significant increase in cell death in cultures. However, a decrease in synaptophysin protein levels by Western blotting occured in all concentrations. These changes in synaptophysin levels were accompanied by JNK activation and ERK inhibition. We also observed a decrease in β-catenin protein immunocontent. The evaluation of GSK-3β and β-catenin phosphorylation showed no significant alterations. Although further studies are necessary for understanding the mechanisms underlying amyloid-β oligomers toxicity, our data suggest synaptic loss in organotypic cultures, one of the earlier characteristics of AD, may be considered a good model to study physiologic factors and pharmacologic compounds AD-related

Questionário Virtual para o Ensino de Probabilidade

http://dx.doi.org/10.5902/2179460X14232As the concept of probability is fundamental to the individual formation due to its form of reasoning,to its applicability and to the professional field, we present a proposal that suggests, first, a problematization then the definition of the probability jargon. It follows that methodology, since the history occurs in this order: first the problems arise, then the concepts and definitions. So, we use the technology in two virtual and interactive quizzes to be solved by students, since playing has an important role during the constrution of the concepts and definitions, the student becomes easily closer to the whole subject.Considerando que o conceito de probabilidade é fundamental para a formação do indivíduo devido à forma de raciocínio, àaplicabilidade e também ao campo profissional promissor, apresentamos uma proposta que sugere, num primeiro momento, umaproblematização para, depois, conceituar e definir os termos que envolvem a Probabilidade. Segue-se essa metodologia, uma vezque a história da probabilidade acontece nessa ordem: primeiro surgem os problemas, depois, os conceitos e as definições. Paraisso, utiliza-se a tecnologia através de um questionário virtual e interativo a ser resolvido pelos discentes. Assim, aproxima-se oeducando do assunto, já que este participa da construção dos conceitos e definições

Curvilinear coordinate system used to solve tritium dispersion in complex orographies

In this contribution we present progress on research concerning dispersion of tritium around the Angra Nuclear Power Plant (Angra dos Reis, Rio de Janeiro state, Brazil). In particular, we are interested in studying how dispersion behaves in scenarios with complex orography. Our proposal is to transform a problem with curvilinear boundaries into an equivalent problem with plane parallel boundaries. We modify the coordinate system through a diffeomorph conformal transformation. Consequently, the operators of the dynamical equations change according to the additional terms from the affine connection. To define the transformation it is necessary to satisfy strong constraints, i.e., boundaries shall be “smooth”. Even with restrictions, our model can be implemented in several situations. A flat region is a particular case of a curvilinear domain and can be studied, where the height of the boundary layer above rivers, lakes, basins is typically smaller and thus implies a varying boundary layer height, for example. Thus, even in flat regions variations in the boundary layer occur, which characterizes a case of a curvilinear domain. There are several nuclear power plants worldwide, that are located in mountainous regions, as for example in Japan and Brazil.We present a simulation of tritium dispersion specifically in the area where the Angra 2 Nuclear Power Plant is located and where the relief is characterized by a considerable complexity. With the intention of showing that the methodology is consistent, we will consider only the variation of the relief

Application of multivariable control using artificial neural networks in a debutanizer distillation column

LOPES, Jose Soares Batista et al. Application of multivariable control using artificial neural networks in a debutanizer distillation column.In: INTERNATIONAL CONGRESS OF MECHANICAL ENGINEERING - COBEM, 19, 5-9 nov. 2007, Brasilia. Anais... Brasilia, 2007Abstract. This work has as objective to develop a control strategy based on neural identification of a mutivariable input- mutivariable output (MIMO) process. The plant to control was simulated in software HYSYS as a classic debutanizer column. Debutanizer distillation column is used to remove the litht components from the gasoline stream to produce Liquefied Petroleum Gas (LPG). The quality control of the product taking away from the top of the tower is affected by the Outflow Control (FIC-100) and the Temperature Control (TIC-100).The process variables chosen are concentration of i-pentene existing in butanes stream and concentration of i-butene existing in C5+ stream. The manipulated variables chosen are reflux flow rate (the setpoint of FIC-100 in h/m3) and thermal load (the setpoint of TIC-100 in oC). The FIC- 100 is responsible for the control of reflux and the TIC-100 for the control of the temperature in the debutanizer column, changing its thermal load to keeping the C5+ production at acceptable level. The purpose is to substitute two physical controllers, FIC-100 and TIC-100, by a neural control system. An important feature of this work is the use of a control strategy composed by two neural network structures: Neuroidentifier and Neurocontroller, responsible respectively for identifying and controlling the process.The software implementation of the artificial neural networks is made using Borland C++ Builder, and its communication with HYSYS is carried through the Microsoft Component Object Model (COM

Calcium and Magnesium Ratio in Alfalfa Cultivation / Proporção Cálcio e Magnésio no Cultivo de Alfafa

The Alfalfa is an important forage for animal feeding, used in breeding of specialized herds due to its high protein content, besides having high palatability and energy value. In this context, the objective of this study was to evaluate the effect of calcium and magnesium ratio in the correction of Oxisol for the cultivation of alfalfa (Medicago sativa L.) cv. Creole. The experiment was conducted in the greenhouse at Federal University of Mato Grosso, Campus Rondonópolis-MT. The experimental design was completely randomized with nine treatments relating about calcium/magnesium nutrients: 0/0; 1/0; 0/1; 3/1; 6/1; 9/1; 12/1; 15/1 and 18/1, with 5 repetitions. The evaluated variables were plant height, number of leaves, number of basal shoots, SPAD index, stem diameter, fresh and shoot dry mass, root dry mass and root volume, soil pHCaCl2 and water use efficiency. The results were submitted to analysis of variance and Scott-knott test (p ≤ 0.05). Both the first and second cut, plant height was lower (24.76 ± 2.57 and 32.82 ± 13.01 cm, respectively) in absence of fertilizers (0/0) in relation to the other ratios. However, the treatments with Ca and/or Mg did not vary significantly, with a mean of 38.07 ± 2.94 and 51.73 ± 7.43 cm, in the first and second cut, respectively. The shoot dry mass showed similar behavior. Lower mass was observed in absence of Ca/Mg in the first cut (1.12 g DM pot-1) and second cut (1.84 g DM pot-1). In the other relations, it was observed a mean of 2.90 and 4.79 g DM pot-1 between the cuts. Likewise, the production of root was lower in absence of fertilizers (1.66 ± 1.05 g DM pot-1) and the others Ca/Mg ratios did not differ from each other (6.14 ± 1.98 g DM pot-1). The SPAD index there was significant effect only in the first cut between the ratio 0/0 and the others, with a mean of 43.48 ± 2.83 and 48.85 ± 2.19, respectively. In the second cut, SPAD index was 38.47 ± 5.82. Soil pH ranged from 5.87 to 5.31 between the cuts. Alfalfa was low sensitive to calcium and magnesium ratios in soil correction, but responded positively to the plant development with increased base saturation