Investigation of peak shapes in the MIBETA experiment calibrations

In calorimetric neutrino mass experiments, where the shape of a beta decay spectrum has to be precisely measured, the understanding of the detector response function is a fundamental issue. In the MIBETA neutrino mass experiment, the X-ray lines measured with external sources did not have Gaussian shapes, but exhibited a pronounced shoulder towards lower energies. If this shoulder were a general feature of the detector response function, it would distort the beta decay spectrum and thus mimic a non-zero neutrino mass. An investigation was performed to understand the origin of the shoulder and its potential influence on the beta spectrum. First, the peaks were fitted with an analytic function in order to determine quantitatively the amount of events contributing to the shoulder, also depending on the energy of the calibration X-rays. In a second step, Montecarlo simulations were performed to reproduce the experimental spectrum and to understand the origin of its shape. We conclude that at least part of the observed shoulder can be attributed to a surface effect

Study of PVI-based diagnostics for 1D time-series in space plasma

Context. In the last few decades, increasing evidence has been found in both numerical studies and high-resolution in situ data that magnetic turbulence spontaneously generates coherent structures over a broad range of scales. Those structures play a key role in energy conversion because they are sites where magnetic energy is locally dissipated in plasma heating and particle energization. How much turbulent energy is dissipated via processes such as magnetic reconnection of thin coherent structures, namely current sheets, remains an open question. Aims. We aim to develop semi-automated methods for detecting reconnection sites over multiple spatial scales. This is indeed pivotal in advancing our knowledge of plasma dissipation mechanisms and for future applications to space data. Methods. By means of hybrid-Vlasov-Maxwell 2D-3V simulations, we combine three methods based on the partial variance of increments measured at a broad range of spatial scales and on the current density, which together, and in a synergistic way, provide indications as to the presence of sites of magnetic reconnection. We adopt the virtual satellite method, which in upcoming works will allow us to easily extend this analysis to in situ time-series. Results. We show how combining standard threshold analysis to a 2D scalogram based on magnetic field increments represents an efficient diagnostic for recognizing reconnecting structure in 1D spatial- and time-series. This analysis can serve as input to automated machine-learning algorithms

Correlação entre medidas de condutividade elétrica em sistema de integração lavoura-pecuária.

Apsul América

Análise exploratória de dados de monitoramento dos animais em um sistema de integração lavoura-pecuária.

Resumo: A aplicação dos preceitos da Agricultura de Precisão em um sistema de Integração Lavoura-Pecuária (ILP) envolve um grau de dificuldade maior devido ao número de fatores envolvidos e a presença da componente animal. Variáveis como a mobilidade, pisoteio, dejeções dos animais e zonas preferenciais podem impactar o sistema e devem ser consideradas. O objetivo deste trabalho é realizar uma análise exploratória dos dados de monitoramento de animais em um sistema ILP. Os dados foram obtidos por aparelhos GPS afixados em animais do rebanho e complementados por observações de campo. São apresentados mapas derivados da aplicação do estimador de intensidade Kernel para situações distintas e levantadas hipóteses sobre os comportamentos dos animais

Análise exploratória de dados de monitoramento dos animais em um sistema de integração lavoura-pecuária.

Resumo: A aplicação dos preceitos da Agricultura de Precisão em um sistema de Integração Lavoura-Pecuária (ILP) envolve um grau de dificuldade maior devido ao número de fatores envolvidos e a presença da componente animal. Variáveis como a mobilidade, pisoteio, dejeções dos animais e zonas preferenciais podem impactar o sistema e devem ser consideradas. O objetivo deste trabalho é realizar uma análise exploratória dos dados de monitoramento de animais em um sistema ILP. Os dados foram obtidos por aparelhos GPS afixados em animais do rebanho e complementados por observações de campo. São apresentados mapas derivados da aplicação do estimador de intensidade Kernel para situações distintas e levantadas hipóteses sobre os comportamentos dos animais

The 4 K outer cryostat for the CUORE experiment: construction and quality control

The external shell of the CUORE cryostat is a large cryogen-free system designed to host the dilution refrigerator and the bolometers of the CUORE experiment in a low radioactivity environment. The three vessels that form the outer shell were produced and delivered to the Gran Sasso underground Laboratories in July 2012. In this paper, we describe the production techniques and the validation tests done at the production site in 2012.Comment: 11 pages, 13 figures; to appear in NIM

A bolometric measurement of the antineutrino mass

High statistics calorimetric measurements of the beta spectrum of 187Re are being performed with arrays of silver perrhenate crystals operated at low temperature. After a modification of the experimental set-up, which allowed to substantially reduce the background of spurious counts and therefore to increase the sensitivity on the electron antineutrino mass, a new measurement with 10 silver perrhenate microbolometers is running since July 2002. The crystals have masses between 250 and 350 micrograms and their average FWHM energy resolution, constantly monitored by means of fluorescence X-rays, is of 28.3 eV at the beta end-point. The Kurie plot collected during 4485 hours x mg effective running time has an end-point energy of 2466.1 +/- 0.8{stat} +/- 1.5 {syst} eV, while the half lifetime of the decay is found to be 43.2 +/- 0.2{stat} +/- 0.1{syst} Gy. These values are the most precise obtained so far for 187Re. From the fit of the Kurie plot we can deduce a value for the squared electron antineutrino mass m(nu)^2 of 147 +/- 237{stat} +/- 90{syst} eV^2. The corresponding 90% C.L. upper limit for m(nu) is 21.7 eV.Comment: 3 pages, 3 figures. Submitted to Phys. Rev. Let

A diguanylate cyclase regulates motility and biofilm formation in Bordetella bronchiseptica mediated by a GGDEF-EAL protein

Bordetella bronchiseptica is a bacterium that causes respiratory infections in a variety of mammalian hosts. We have already described c-di-GMP role in motility and biofilm formation. We previously showed that over expressing BdcA (Bordetella diguanylate cyclase A) triggers high c-di-GMP levels and significantly impaired movement and enhanced biofilm formation.Facultad de Ciencias Exacta