Use of filamentous fungi for improving electricity production and textile dye treatment in a microbial fuel cell

Urban and industrial wastewaters have received an increased interest towards energy harvesting using microbial fuel cells (MFC). The combined use of microbial anode oxidizing organic substrates and enzymatic cathode reducing oxygen is a promising new approach for the simultaneous treatment of wastewater and generation of electricity. In this context, our study evaluated the performance of a two-chambered MFC operated with three laccase producing strains of filamentous fungi (Ff), immobilized on the cathodic compartment and filled up with simulated textile dye effluent (TDE) and urban wastewater in the anodic compartment. The result indicated a rapid TDE decolourisation (>86 % within 72 h). Electrochemical monitoring of the MFC during TDE decolourisation indicated power density (>35 mW m2, control 3,61) and laccase activity (989.6 U l–1) in the presence of Pleurotus ostreatus on the cathodic compartment. Considering the initial COD value of 464 ± 20 mg.l-1, the organic removal in the anodic compartment after 20 days of MFC operation was 90.2%. Final toxicity measurements in the TDE treated indicated a much lower impact when compared to the original TDE. These are the initial studies to select Ff as models for MFC application and further adaptation for wastewater treatment and bioelectricity generatio

Avaliação de desempenho de uma célula de combustível microbiana em sedimentos de sistemas aquáticos eutrofizados

Em ecossistemas aquáticos, a incorporação de um ânodo nos sedimentos anaeróbios e a colocação de um cátodo suspenso na coluna de água, pode permitir uma produção descentralizada de bioeletricidade. Nesse sentido, o presente trabalho apresenta os resultados de operação de uma SMFC laboratorial com diferentes configurações de elétrodos e tipo de materiais (carbono e aço). Os resultados obtidos mostraram uma produção contínua de bioeletricidade, com o máximo de voltagem (~100 mV) a ser atingido após um mês de operação. Depois do valor máximo de produção de bioeletricidade a corrente diminuiu, provavelmente devido a limitações de transferência de massa. O aumento da área de ânodo, através da incorporação de um novo eletrodo, resultou no aumento da voltagem obtida (~30 mV para ~60 mV com a colocação de um novo ânodo de carbono com a mesma área e de ~20 mV para 65 mV com a colocação de um ânodo de aço inoxidável). Em conclusão, a tecnologia das MFC aplicada a sistemas sedimentares pode representar, em certos casos, uma inovadora oportunidade de valorização em sistemas aquáticos eutrofizados

Leachate treatment process at a municipal stabilized landfill by catalytic ozonation: an exploratory study from Taguchi orthogonal array

Catalytic ozonation has been recognized in the scientific community as an efficient technique, reaching elevated rates of recalcitrant organic material mineralization, even at the presence of scavenger species of hydroxyl free radicals. This study presents the most significant factors involving the leachate treatment stabilized by the municipal landfill of the city of Guaratinguetá, State of São Paulo, Brazil, by using a catalytic ozonation activated by metallic ions Fe3+, Zn2+, Mn2+, Ni2+ and Cr3+. The Taguchi L16 orthogonal array and its associated statistical methods were also used in this study. Among the researched ions, the most notable catalysis was obtained with ferric ion, statistically significant in the reduction of COD with a confidence level of 99.5%.Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES

Atividade microbiana do solo sob diferentes cultivos irrigados em um Argissolo Vermelho Amarelo distrófico no Submédio São Francisco.

Este trabalho tem por objetivo avaliar a atividade biológica do solo sob diferentes cultivos com uso de irrigação e sua comparação com áreas de Caatinga. As amostras foram coletadas em novembro de 2006 em áreas com cultivo de manga, uva, culturas anuais, banana e em reserva de vegetação natural, no Campo Experimental da Embrapa Semi-¡rido no Distrito Irrigado de Bebedouro

Dirac fields, torsion and Barbero-Immirzi parameter in Cosmology

We consider cosmological solution for Einstein gravity with massive fermions with a four-fermion coupling, which emerges from the Holst action and is related to the Barbero-Immirzi (BI) parameter. This gravitational action is an important object of investigation in a non-perturbative formalism of quantum gravity. We study the equation of motion for for the Dirac field within the standard Friedman-Robertson-Walker (FRW) metric. Finally, we show the theory with BI parameter and minimally coupling Dirac field, in the zero mass limit, is equivalent to an additional term which looks like a perfect fluid with the equation of state \ $p = w\rho$, with $w = 1$ which is independent of the BI parameter. The existence of mass imposes a variable $w$, which creates either an inflationary phase with $w=-1$, or assumes an ultra hard equation of states $w = 1$ for very early universe. Both phases relax to a pressure less fluid $w = 0$ for late universe (corresponding to the limit $m\to\infty$).Comment: LaTeX file (with jcappub.sty), 16 pages, no figures. Some formulations and discussions slightly modified, fits the version to be published in JCA

Influence of the A286G polymorphism in the LEPR gene on carcass traits in a paternal broiler line.

Projeto/Plano de Ação: 01.06.01.006

Caracterização molecular e morfológica do agente etiológico da pinta preta em solanáceas no Brasil.

Este trabalho objetivou realizar a caracterização molecular e morfológica de isolados de Alternaria obtidos de solanáceas.Resumo 504_1

The Network of Epicenters of the Olami-Feder-Christensen Model of Earthquakes

We study the dynamics of the Olami-Feder-Christensen (OFC) model of earthquakes, focusing on the behavior of sequences of epicenters regarded as a growing complex network. Besides making a detailed and quantitative study of the effects of the borders (the occurrence of epicenters is dominated by a strong border effect which does not scale with system size), we examine the degree distribution and the degree correlation of the graph. We detect sharp differences between the conservative and nonconservative regimes of the model. Removing border effects, the conservative regime exhibits a Poisson-like degree statistics and is uncorrelated, while the nonconservative has a broad power-law-like distribution of degrees (if the smallest events are ignored), which reproduces the observed behavior of real earthquakes. In this regime the graph has also a unusually strong degree correlation among the vertices with higher degree, which is the result of the existence of temporary attractors for the dynamics: as the system evolves, the epicenters concentrate increasingly on fewer sites, exhibiting strong synchronization, but eventually spread again over the lattice after a series of sufficiently large earthquakes. We propose an analytical description of the dynamics of this growing network, considering a Markov process network with hidden variables, which is able to account for the mentioned properties.Comment: 9 pages, 10 figures. Smaller number of figures, and minor text corrections and modifications. For version with full resolution images see http://fig.if.usp.br/~tpeixoto/cond-mat-0602244.pd