On the description of non-unitary neutrino mixing

Neutrino oscillations are well established and the relevant parameters determined with good precision, except for the CP phase, in terms of a unitary lepton mixing matrix. Seesaw extensions of the Standard Model predict unitarity deviations due to the admixture of heavy isosinglet neutrinos. We provide a complete description of the unitarity and universality deviations in the light neutrino sector. Neutrino oscillation experiments involving electron or muon neutrinos and anti-neutrinos are fully described in terms of just three new real parameters and a new CP phase, in addition to the ones describing oscillations with unitary mixing. Using this formalism we describe the implications of non-unitarity for neutrino oscillations and summarize the model-independent constraints on heavy neutrino couplings that arise from current experiments.Comment: 28 pages, 8 figures, typos corrected, modified bounds on non-unitarity parameters, new figs 3 and

Sensitivity of low energy neutrino experiments to physics beyond the standard model

We study the sensitivity of future low energy neutrino experiments to extra neutral gauge bosons, leptoquarks and R-parity breaking interactions. We focus on future proposals to measure coherent neutrino-nuclei scattering and neutrino-electron elastic scattering. We introduce a new comparative analysis between these experiments and show that in different types of new physics it is possible to obtain competitive bounds to those of present and future collider experiments. For the cases of leptoquarks and R-parity breaking interactions we found that the expected sensitivity for most of the future low energy experimental setups is better than the current constraints.Comment: 21 pages, 5 figures. A more detailed analysis of systematic errors is done. Final version to be published in PR

A non-resonant dark-side solution to the solar neutrino problem

We re-analyse spin-flavour precession solutions to the solar neutrino problem in the light of the recent SNO CC result as well as the 1258--day Super-Kamiokande data and the upper limit on solar anti-neutrinos. In a self-consistent magneto-hydrodynamics approach the resulting scheme has only 3 effective parameters: $\Delta m^2$, $\mu B_\perp$ and the neutrino mixing angle $\theta$. We show how a rates-only analysis for fixed $\mu B_\perp$ slightly favours spin-flavour precession (SFP) solutions over oscillations (OSC). In addition to the resonant solution (RSFP for short), there is a new non-resonant solution (NRSFP) in the ``dark-side''. Both RSFP and NRSFP lead to flat recoil energy spectra in excellent agreement with the latest SuperKamiokande data. We also show that in the presence of a neutrino transition magnetic moment of $10^{-11}$ Bohr magneton, a magnetic field of 80 KGauss eliminates all large mixing solutions other than the so-called LMA solution.Comment: 12 pages, 3 postscript figures, using elsart.cls. Published versio

A multifractal approach to characterize cumulative rainfall and tillage effects on soil surface micro-topography and to predict depression storage

Most of the indices currently employed for assessing soil surface micro-topography, such as random roughness (RR), are merely descriptors of its vertical component. Recently, multifractal analysis provided a new insight for describing the spatial configuration of soil surface roughness. The main objective of this study was to test the ability of multifractal parameters to assess in field conditions the decay of initial surface roughness induced by natural rainfall under different soil tillage systems. In addition, we evaluated the potential of the joint use of multifractal indices plus RR to improve predictions of water storage in depressions of the soil surface (MDS). Field experiments were performed on an Oxisol at Campinas, São Paulo State (Brazil). Six tillage treatments, namely, disc harrow, disc plough, chisel plough, disc harrow + disc level, disc plough + disc level and chisel plough + disc level were tested. In each treatment soil surface micro-topography was measured four times, with increasing amounts of natural rainfall, using a pin meter. The sampling scheme was a square grid with 25 × 25 mm point spacing and the plot size was 1350 × 1350 mm (≈1.8 m<sup>2</sup>), so that each data set consisted of 3025 individual elevation points. Duplicated measurements were taken per treatment and date, yielding a total of 48 experimental data sets. MDS was estimated from grid elevation data with a depression-filling algorithm. Multifractal analysis was performed for experimental data sets as well as for oriented and random surface conditions obtained from the former by removing slope and slope plus tillage marks, respectively. All the investigated microplots exhibited multifractal behaviour, irrespective of surface condition, but the degree of multifractality showed wide differences between them. Multifractal parameters provided valuable information for characterizing the spatial features of soil micro-topography as they were able to discriminate data sets with similar values for the vertical component of roughness. Conversely, both, rough and smooth soil surfaces, with high and low roughness values, respectively, can display similar levels of spectral complexity. Although in most of the studied cases trend removal produces increasing homogeneity in the spatial configuration of height readings, spectral complexity of individual data sets may increase or decrease, when slope or slope plus tillage tool marks are filtered. Increased cumulative rainfall had significant effects on various parameters from the generalized dimension, <i>D</i><sub>q</sub>, and singularity spectrum, <i>f</i>(α). Overall, micro-topography decay by rainfall was reflected on a shift of the singularity spectra, <i>f</i>(α) from the left side (<i>q</i>>>0) to the right side (<i>q</i><<0) and also on a shift of the generalized dimension spectra from the right side (<i>q</i>>>0) to the left side (<i>q</i><<0). The use of an exponential model of vertical roughness indices, RR, and multifractal parameters accounting for the spatial configuration such as <i>D</i><sub>1</sub> or <i>D</i><sub>5</sub> improved estimation of water stored in surface depressions

Millimeter wave transmission studies of YBa2Cu3O7-delta thin films in the 26.5 to 40.0 GHz frequency range

Millimeter wave transmission measurements through YBa2Cu3O(7-delta) thin films on MgO, ZrO2 and LaAlO3 substrates, are reported. The films (approx. 1 micron) were deposited by sequential evaporation and laser ablation techniques. Transition temperatures T sub c, ranging from 89.7 K for the Laser Ablated film on LaAlO3 to approximately 72 K for the sequentially evaporated film on MgO, were obtained. The values of the real and imaginary parts of the complex conductivity, sigma 1 and sigma 2, are obtained from the transmission data, assuming a two fluid model. The BCS approach is used to calculate values for an effective energy gap from the obtained values of sigma sub 1. A range of gap values from 2 DELTA o/K sub B T sub c = 4.19 to 4.35 was obtained. The magnetic penetration depth is evaluated from the deduced values of sigma 2. These results are discussed together with the frequency dependence of the normalized transmission amplitude, P/P sub c, below and above T sub c

Produção orgânica de cana-de-açúcar, manejo e biodiversidade.

Este trabalho objetivou trazer um resumo do conjunto das ações e práticas diferenciais de cultivo orgânico e manejo ecológico em um agroecossistema de cana-de-açúcar. Foi utilizada ampla revisão bibliográfica, consulta a acervos técnicos e científicos especializados, observações e incursões a campo. Foram analisadas as informações disponíveis, como documentos, diagnósticos, relatórios, dados primários e secundários. Os resultados das ações e práticas implementadas foram positivos e benéficos nas esferas ambientais, econômicas e sociais, diferentemente daqueles praticados nos sistemas convencionais. O modelo avaliado mostrou-se importante e efetivo na recuperação, conservação e manutenção da biodiversidade, além de se mostrar eficiente como instrumento de minimização dos impactos sociais associados ao setor. O sistema evidenciou um maior patamar de sustentabilidade quando comparado ao convencional

Consequências do cultivo orgânico da cana-de-açúcar, sob o manejo ecológico sobre a biodiversidade faunística.

A fauna silvestre em áreas agrícolas é um fato ainda pouco estudado. O tipo de manejo empregado promoverá uma discriminação diferenciada sobre a composição dos povoamentos faunísticos. Esse projeto de pesquisa foi desenvolvido pela equipe da EMBRAPA Monitoramento por Satélite e visou detectar e caracterizar a biodiversidade de vertebrados em território delimitado. A área de estudo compreende um conjunto de fazendas com 7.868 hectares sob cultivo orgânico e manejo ecológico, localizadas na região de Ribeirão Preto, SP. Através do emprego de imagens do satélite QuickBird foi elaborada a carta de uso e cobertura das terras e serviu de base para caracterizar dez tipos de ambientes ou habitats, entre naturais e restaurados, disponíveis para a fauna silvestre. Uma ficha de levantamento précodificada foi estabelecida e utilizada em mais de 2000 levantamentos de campo. Foram registradas e identificadas 331 espécies de vertebrados silvestres no conjunto dos dez ambientes amostrados (27 anfíbios, 19 répteis, 245 aves e 40 mamíferos), das quais 49 das espécies são consideradas ou estão sob algum risco ou ameaça de extinção no estado de São Paulo. O itinerário metodológico adotado para avaliar a biodiversidade faunística permitiu atingir os objetivos da pesquisa e revelou-se plenamente adequado e confirmou sua eficácia. Os resultados obtidos até o momento indicam que o cultivo em sistemas orgânicos, associado ao manejo ecológico tem favorecido a biodiversidade faunística

Produção orgânica de cana-de-açúcar, manejo e biodiversidade: estudo de caso.

Este trabalho objetivou trazer um resumo do conjunto das ações e práticas diferenciais de cultivo orgânico e manejo ecológico em um agroecossistema de cana-de-açúcar. Foi utilizada ampla revisão bibliográfica, consulta a acervos técnicos e científicos especializados, observações e incursões a campo. Foram analisadas as informações disponíveis, como documentos, diagnósticos, relatórios, dados primários e secundários. Os resultados das ações e práticas implementadas foram positivos e benéficos nas esferas ambientais, econômicas e sociais, diferentemente daqueles praticados nos sistemas convencionais. O modelo avaliado mostrou-se importante e efetivo na recuperação, conservação e manutenção da biodiversidade, além de se mostrar eficiente como instrumento de minimização dos impactos sociais associados ao setor. O sistema evidenciou um maior patamar de sustentabilidade quando comparado ao convencional