Photophysics of poly(p-phenylene vinylene) films

We report on time resolved photoluminescence (PLRT) measurements in poly(p-phenylene vinylene) (PPV) films irradiated by laser in the presence of air. We observe a PL intensity enhancement and a biexponential decay dynamics of PL signal for all irradiated films. These results can be understood in terms of a chain shortening process due to carbonyl incorporation and formation of an energy profile that extends and migrates into the film and enables efficient spectral diffusion of excited carriers to a non-degraded PPV segments by Förster energy transfer

Diretrizes curriculares para os cursos de graduação em Geologia e Engenharia Geológica

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Electron reconstruction and identification efficiency measurements with the ATLAS detector using the 2011 LHC proton–proton collision data

Many of the interesting physics processes to be measured at the LHC have a signature involving one or more isolated electrons. The electron reconstruction and identification efficiencies of the ATLAS detector at the LHC have been evaluated using proton–proton collision data collected in 2011 at s√=7 TeV and corresponding to an integrated luminosity of 4.7 fb −1. Tag-and-probe methods using events with leptonic decays of W and Z bosons and J/ψ mesons are employed to benchmark these performance parameters. The combination of all measurements results in identification efficiencies determined with an accuracy at the few per mil level for electron transverse energy greater than 30 GeV

Electronic structure and magnetic properties of selected lanthanide and actinide intermetallic Laves-phase alloys

The electronic structure and magnetic properties of some yttrium and uranium Laves-phase pseudobinary alloys with 3d elements have been calculated. The calculations were done by simulating the electronic structure of the alloy by that of an ordered compound with the same stoichiometry. In general a good agreement between the experimental and theoretical magnetic moment was found, indicating that the spurious long-range order of the calculations is of minor importance. A comparison between the present supercell cluster approach and the virtual-crystal approximation for the electronic structure and cohesive properties is presented for Y(Fe0.75Co0.25)2 and U(Fe0.5Ni0.5)2

Medial prefrontal cortex Transient Receptor Potential Vanilloid Type 1 (TRPV1) in the expression of contextual fear conditioning in Wistar rats

Contextual fear is evoked by re-exposing an animal to an environment that has been previously paired with an aversive or unpleasant stimulus. It can be assessed by freezing and cardiovascular changes such as increase in mean arterial pressure and heart rate. A marked increase in neuronal activity is associated with contextual fear conditioning, especially in limbic structures involved with defense reactions, such as the ventral portion of medial prefrontal cortex. Given the fact that transient receptor potential vanilloid type 1 (TRPV1) receptors could be involved in the expression of defensive behavior, the present work tested the hypothesis that TRPV1 manipulation in the ventromedial prefrontal cortex (vMPFC) modulates the expression of contextual conditioned fear. Male Wistar rats received bilateral microinjections into the vMPFC of the TRPV1 receptor antagonists capsazepine (1, 10, and 60 nmol/200 nL) or 6-iodonordihydrocapsaicin (3 nmol/200 nL), and the TRPV1 agonist capsaicin (1 nmol/200 nL) preceded by vehicle or 6-iodonordihydrocapsaicin before re-exposure to the experimental chamber for 10 min, 48 h after conditioning in two different protocols distinct by their aversiveness. Both antagonists reduced the freezing and cardiovascular responses in the high aversive protocol. Capsaicin caused an increase in fear-associated responses that could be blocked by 6-iodonordihydrocapsaicin. Our results indicate that TRPV1 receptors located in the vMPFC have a tonic involvement in the modulation of the expression of contextual fear conditioning

Efeito do meio de cultura no potencial de inóculo de Colletotrichum graminicola.

Avaliou-se o efeito de meios de cultura no potencial de inoculo de C. graminicola. Conidios produzidos nos meios: FAA meio, FB e de Kado e Heskett foram inoculados em genotipo suscetivos. Apos 20 horas de camara umida, as plantas foram mantidas em casa de vegetacao. As avaliacoesbasearam-se na severidade e periodo latente medio. Os resultados obtidos mostraram que os meios FAAM E FB comportaram-se estatisticamente demodo identico ao meio FAA, induzindo severidade maxima, com notas variando de quatro a cinco. Com relacao ao meio KH observaram-se que conidios produzidos nesse meio embora infectassem, nenhuma lesao esporulou e nesse meio nao foi obtido um periodo latente.Edição dos resumos do XXVIII Congresso Brasileiro de Fitopatologia. Resumo 506

Defect-assisted photoluminescence intensity enhancement in poly(p-phenylene vinylene) films probed by time-resolved photoluminescence

We report on picosecond time resolved photoluminescence measurements in poly(p-phenylene vinylene) (PPV) films of thickness which exceeds the penetration depth of the exciting laser, irradiated by laser in air. The photoluminescence (PL) intensity increases during the irradiation process despite the increasing density of photo-oxidation induced carbonyl groups, usually acting as quenching centers. We study the PL enhancement and the dynamics of the PL decay for different irradiation conditions and different sample thicknesses. The PL decay surprisingly shows a reduced importance of defects trapping as the defect concentration increases, thus explaining the PL enhancement. We explain our results in terms of a chain shortening due to carbonyl incorporation and formation of an energy profile that extends and migrates into the film, enabling efficient spectral diffusion of excited carriers into nondegraded PPV segments by Förster energy transfer