Avaliação espectroscópica de ácidos húmicos extraídos de solos sob adição de diferentes compostos orgânicos.

A crescente produção de resíduos agrícolas vem provocando significativos impactos ambientais, pois sua taxa de geração é muito maior do que a sua taxa de degradação. Neste contexto a compostagem mostra-se como uma alternativa de reaproveitamento, reciclagem e redução destes resíduos gerados pelo homem. No processo de compostagem ocorrem reações bioquímicas para a estabilização do material, estando diretamente associadas à humificação da matéria orgânica, sendo as substancias húmicas seu principal componente. O objetivo do estudo foi analisar os ácidos húmicos extraídos de solos sob disposição de distintos compostos orgânicos por Espectroscopia de Infravermelho com Transformada de Fourier (FTIR). Os resultados sugerem possíveis reações químicas decorrentes da aplicação de diferentes compostos no solo.Disponível também em: Cadernos de Agroecologia, V. 5, n.1, 2010

Multicomutation flow system for spectrophometric total amido acids determination in plant material.

To identify lhe nitrogen transportation forms and attain the control mechanism, the amount of free amino acids in different parts of lhe plant has to be determined. An automatic, fast and reliable procedure multicomutated flow system {1] has been developed for spectrophotometric analysis of totalamino acids in plant material. The method is suitable for routine analysis for a large number of samples of plant material. The flow manifold was designed with computer-controlled three-way solenoid valves for independent handling of sample and reagent solutions and a data acquisition system from a spectrophotometer, employed for signal measurements. The software for system control was performed bya program with use of a LabView platform INationallntruments) [2]. The detection reaction was based on the complexation of amino functional groups of amino acids by ninhydrin. It reacts with free a-amino groups, producing lhe colored ninhydrin chromophore called Ruhemann's purple IRP) IAm". = 570 nm; E = 22 000) [3]. The proposed detection system shows a linear range concentration up to 2.0 X 10-3 mal L-I with coefficient of variation of 1.1% (n = 101. Detection limits were estimated as 2.8 x 10-3 mal L-I at 99.7% confidence level for total amino acids. and a mean sampling rale of 30 determinations per hour was achieved

Performance of a Tungsten-Cerium Fluoride Sampling Calorimeter in High-Energy Electron Beam Tests

A prototype for a sampling calorimeter made out of cerium fluoride crystals interleaved with tungsten plates, and read out by wavelength-shifting fibres, has been exposed to beams of electrons with energies between 20 and 150 GeV, produced by the CERN Super Proton Synchrotron accelerator complex. The performance of the prototype is presented and compared to that of a Geant4 simulation of the apparatus. Particular emphasis is given to the response uniformity across the channel front face, and to the prototype's energy resolution.Comment: 6 pages, 6 figures, Submitted to NIM

Response of microchannel plates in ionization mode to single particles and electromagnetic showers

Hundreds of concurrent collisions per bunch crossing are expected at future hadron colliders. Precision timing calorimetry has been advocated as a way to mitigate the pileup effects and, thanks to their excellent time resolution, microchannel plates (MCPs) are good candidate detectors for this goal. We report on the response of MCPs, used as secondary emission detectors, to single relativistic particles and to electromagnetic showers. Several prototypes, with different geometries and characteristics, were exposed to particle beams at the INFN-LNF Beam Test Facility and at CERN. Their time resolution and efficiency are measured for single particles and as a function of the multiplicity of particles. Efficiencies between 50% and 90% to single relativistic particles are reached, and up to 100% in presence of a large number of particles. Time resolutions between 20ps and 30ps are obtained.Comment: 20 pages, 9 figures. Paper submitted to NIM

Engineering donor mesenchymal cells with IL-7 hastens naive T cell recruitment in vitro and supports immunologic reconstitution after HSCT in NOD/SCID mice

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Holographic renormalization and supersymmetry

Holographic renormalization is a systematic procedure for regulating divergences in observables in asymptotically locally AdS spacetimes. For dual boundary field theories which are supersymmetric it is natural to ask whether this defines a supersymmetric renormalization scheme. Recent results in localization have brought this question into sharp focus: rigid supersymmetry on a curved boundary requires specific geometric structures, and general arguments imply that BPS observables, such as the partition function, are invariant under certain deformations of these structures. One can then ask if the dual holographic observables are similarly invariant. We study this question in minimal N = 2 gauged supergravity in four and five dimensions. In four dimensions we show that holographic renormalization precisely reproduces the expected field theory results. In five dimensions we find that no choice of standard holographic counterterms is compatible with supersymmetry, which leads us to introduce novel finite boundary terms. For a class of solutions satisfying certain topological assumptions we provide some independent tests of these new boundary terms, in particular showing that they reproduce the expected VEVs of conserved charges.Comment: 70 pages; corrected typo