Identificação de fungos em mudas de mangueiras apresentando morte súbita.

Suplemento. Edição dos Resumos do 44 Congresso Brasileiro de Fitopatologia, Bento Gonçalves, ago. 2011

Seca-da-mangueira detecção, sintomatologia e controle.

O cultivo da mangueira È uma das principais atividades agrícolas do polo de fruticultura Petrolina-PE/Juazeiro-BA, contribuindo com mais de 90% da exportação nacional de manga. Apesar do bom desempenho desse polo agrícola em relação as demais áreas produtoras do país, as ocorrências de doenças como antracnose, malformação floral e vegetativa e podridões causadas por diferentes patógenos vem se tornando cada vez mais relevantes, apesar de o clima semi-árido ser, na maior parte do ano, desfavorável alta incidência de doenças, quando comparado as outras regiões produtoras do país. Para que essa regi„o continue sendo o principal polo produtor/exportador no cenário nacional, é imprescindível que a qualidade fitossanitária do pomar seja resguardada

Análise da sensibilidade e especificidade do gene virB5 na detecção de Brucella spp. por PCR em sangue de bovinos.

Trabalho 1

Theoretical study of the influence of chemical defects on the molecular properties of semiconducting polymers

Semiconductor polymers are successfully implemented in a broad range of applications such as light emitting diodes, field effect transistors and photovoltaic devices. Most of the achievements reached in the development of these devices were obtained at experimental level, being difficult to identify individually the influence of each factor that limits and controls these devices efficiency. One of the factors that strongly influence the performance of polymer-based devices is the presence of chemical defects in the polymer strands that change their molecular properties. As a result, these polymer strands can work like traps or deep energetic states for charge transport, leading, for instance, to a decrease on charge mobility. At experimental level it is a difficult task to isolate the influence of each type of chemical defects individually on the molecular properties of the polymer strands. It is in this context that theoretical modelling seems to be the most suitable approach to get a deep understanding of the influence of chemical defects on the molecular properties of semiconductor polymers. By performing quantum molecular dynamics calculations we study the influence of chemical defects on the molecular properties of poly(para-phenylenevinylene) (PPV). Our results show clearly a significant difference on the electronic properties of defective polymer strands (e.g. charge carrier localization, ionization potential, electron affinity and electric-field threshold for charge carrier mobility along the polymer backbone) as compared with defect-free strands.Fundação para a Ciência e a Tecnologia (FCT) - CONC-REEQ/443/EEI/2005, SFRH/BD/22143/200

The influence of nanostructure on polymer-based optoelectronic devices functioning: a computer simulation study

During the last years it has been clear that it is importance to understand and control the nanostructure of the active polymer layer used in optoelectronic devices, like polymer diodes, solar cells or field effect transistors. Several experimental studies have shown that the nanostructure of polymer thin films used in these optoelectronic devices depends on the conditions used to deposit the polymer layer between the electrodes. As a result, in solid state conjugated polymer chains tend to be stacked and aligned relative to the electrodes creating domains with different sizes that influence the performance of these devices. To understand how the spatial arrangement of polymer chains affects the functioning of optoelectronic devices, we performed computer simulations using our mesoscopic model based on a generalized dynamic Monte Carlo method. We focus our study on the influence of the nanomorphology on the electric properties of polymer light emitting diodes. Our results show that for a pristine polymer layer and in the presence of ohmic contacts between the electrodes and the polymer layer, the electric properties of the device, namely current density, charge density, internal electric field and the number of charges that undergo recombination strongly depends on the polymer morphology at nanoscale.Fundação para a Ciência e a Tecnologia (FCT) - SFRH/BD/22143/2005Fundo Europeu de Desenvolvimento Regional (FEDER) – Programa Operacional “Ciência , Tecnologia, Inovação” – POCTI/CTM/41574/2001, CONC-REEQ/443/EEI/200

Quantum and nanoscale modelling of exciton dynamics in polymeric systems

One of the factors that limit the efficiency of polymer-based optoelectronic devices, such as photovoltaic solar cells and light emitting diodes, is the exciton diffusion within the polymeric network. Due to the amorphous nature the of polymeric materials, the diffusion of excitons is limited by the energetic and spatial disorder in such systems, which is a consequence not only of the chemical structure of the polymer but also from its orphology at nanoscale. To get a deep understanding on how such effects influence exciton dynamics we performed a quantum molecular dynamics simulations to determine the energetic disorder within the polymer system, and Monte Carlo simulations to study exciton diffusion in three-dimensional (3D) polymer networks that present both spatial and energetic disorder at nanometre scale. Our results show clearly that exciton diffusion in poly(p-phenylenevenylene) (PPV) occurs preferentially in the direction parallel to the electrodes surface for a polymer-based optoelectronic devices with the orientation of the conjugated strands similar to those obtained by the spin-coating technique and the decay of such excitons occurs preferentially in longer strands which allow us to get insight on exciton behaviour in polymeric systems that are not possible to be obtained directly from the experiments.Fundação para a Ciência e a Tecnologia (FCT) – POCTI/CTM/41574/2001, CONC-REEQ/443/EEI/2005, SFRH/BD/22143/2005Fundação Calouste Gulbenkia

Impacto da cobertura plástica na intensidade do oídio da videira.

Suplemento. Ref. EPI-032. Edição dos Resumos do 41. Congresso Brasileiro de Fitopatologia, Belo Horizonte, ago. 2008

Thermochemical pre- and biological co-treatments to improve hydrolysis and methane production from poultry wastes

Poultry industry wastes, namely feathers and poultry litter, are an interesting source of substrate for biogas production. The aim of this work was to assess the biomethane potential of raw poultry wastes, as well as the possibility of enhancing this potential by favouring the hydrolysis of cellulolytic and proteinaceous material in the wastes by using bioaugmentation and thermochemical pre-treatments. Biomethane production from poultry litter and chicken feathers was assessed in batch assays. Pre-treatment with lime and sodium hydroxide was performed at different temperatures and pressures. Clostridium cellulolyticum, C. saccharolyticum and C. thermocellum were used as bioaugmentation strains in the anaerobic digestion of poultry litter. Fervidobacterium pennivorans was used to aid the hydrolysis of poultry feather. Anaerobic digestion of the raw wastes allowed a methanisation percentage (MP) of 17±2 and 33±5%, respectively from poultry litter and chicken feathers, with 2.5% total solids. The major increase in biomethanisation of poultry litter was reached after the thermochemical pre-treatment with Ca(OH)2 (90 °C, 1.27 bar, 120 minutes), with an increase of 15% in the MP comparatively with the raw wastes MP. For the poultry feathers waste, none of the implemented strategies contributed to the optimization of methane production. However, it was observed that all treatments have contributed to a significant increase in the wastes solubilisation. Therefore, the conversion of soluble organic matter to methane was the limiting step of the anaerobic digestion process of poultry wastes