First Description of a Cluster of Acute/Subacute Paracoccidioidomycosis Cases and Its Association with a Climatic Anomaly

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Anomaly-free constraints in neutrino seesaw models

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Gadolinium-doped cerium oxide nanorods: novel active catalysts for ethanol reforming

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Synthesis, characterization and thermal behaviour of solid-state compounds of europium(III) and gadolinium(III) 3-methoxybenzoate

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

NOLEN-SCHIFFER ANOMALY AND RHO(0)-OMEGA MIXING

The Nolen-Schiffer anomaly is the long standing discrepancy between theory and experiment of binding energy differences of mirror nuclei. It appears that the anomaly is largely explained by the charge symmetry breaking force generated by the rho(0)-omega mixing. In this paper I discuss the effect of the rho(0)-omega mixing to the binding energy differences in relativistic models of the nucleus. I also discuss the issue of momentum dependence of rho(0)-omega mixing amplitude and present an alternative explanation of the anomaly based on the partial restoration of chiral symmetry in the nucleus.

A model for the Schottky anomaly in metallic Nd2-yCeyCuO4

We present a simple model for the doped compound Nd2-yCevCuO4, in order to explain some recent experimental results on the latter. Within a Hartree-Fock context, we start from an impurity Anderson-like model and consider the magnetic splitting of the Nd-4f ground state Kramers doublet due to exchange interactions with the ordered Cu moments. Our results are in very good agreement with the experimental data, yielding a Schottky anomaly peak for the specific heat that reduces its amplitude, broadens and shifts to lower temperatures, upon Ce doping. For overdoped compounds at low temperatures, the specific heat behaves linearly and the magnetic susceptibility is constant. A smooth transition from this Fermi liquid-like behavior occurs as temperature is increased and, at high temperatures, the susceptibility exhibits a Curie-like behavior. Finally, we discuss some improvements our model is amenable to incorporate, (C) 1998 Elsevier B.V. B.V. All rights reserved.

Unusual early morning development of the equatorial anomaly in the Brazilian sector during the Halloween magnetic storm

The solar events that occurred at the end of October 2003 gave rise to very strong geomagnetic disturbances that peaked twice with Dst values reaching -345 nT around 0000 UT on 30 October and -400 nT around 2300 UT, on the same day. Disturbances in several ionospheric parameters were observed over Brazil. This work will focus on the ionospheric response to the initial westward prompt penetration electric field and on the strong intensification of the equatorial ionization anomaly that occurred because of the electric field polarity reversal that followed in the early morning hours of 29 October. The F layer peak height over the equator first decreased under the strong prompt penetration westward electric field, which was followed by significant height increase under eastward electric field. We have used Sheffield University Plasmasphere Ionosphere Model (SUPIM) with an intensified westward disturbed electric field in the presunrise hours, presumably due to prompt penetration from the magnetosphere, in order to study the effect of such a field in the ionosphere. The simulation results showed that prompt penetration of magnetospheric electric fields of westward polarity to the nightside equatorial region seems to be the most probable cause of the initial F layer height decreases. The intensification of the equatorial ionization anomaly and the unusual enhancement on F layer peak density, which was not modeled by the SUPIM, are explained as caused by the strong eastward electric field that followed the initial phase in combination with a highly variable disturbed meridional/transequatorial wind system as inferred from the F2 layer peak height variations. The highly dynamic wind pattern, with a short-term response (2-4 hours), is compatible with the predictions of some previous theoretical model calculations reported in the literature.

Eu3+ as a spectroscopic probe in phosphors based on spherical fine particle gadolinium compounds

This work reports on the luminescence spectroscopy sensitivity in the determination of the phase purity in gadolinium compounds using Eu3+ as a probe. Cubic Gd2O3 and hexagonal Gd2O2S doped with Eu3+ spherical fine particles were obtained from doped gadolinium basic carbonates with morphological control and were also characterized by IR and XRD. Doped samples present Eu3+ characteristic transitions, with specific energy positions related to each phase. Emission and excitation spectra patterns were established for oxide and oxysulfide compounds, then oxysulfate and oxide impurities generated during oxysulfide preparation were monitored. From emission spectra some experimental intensity parameters were also calculated. All spectroscopic results reflect the presence or not of impurities in all compounds. (C) 2001 Elsevier B.V. Ltd. All rights reserved.

Red and blue emissions of europium doped gadolinium silicate from porous silica matrix and hydroxide carbonate with spherical shaped particles

In this work, Eu(III) and Eu(II) doped gadolinium silicates has been obtained as compact tubes starting from spherical gadolinium hydroxide carbonate using the pores of silica matrix as support and its surface as reagent. Eu(III) doped gadolinium silicate with hexagonal phase shows an interesting visible shifted charge transfer band when compared to disilicate with orthorhombic phase that was also obtained. Eu(II) gadolinium silicate has been prepared using CO atmosphere presenting an intense blue emission. The divalent europium system shows a potential application as an UV-blue converter. The samples were characterized by scanning electron microscopy (SEM), X-ray powder diffractometry (XRD) and photoluminescence spectroscopy. (C) 2002 Elsevier B.V. B.V. All rights reserved.

The SU(2) Skyrme model and anomaly

The SU(2) Shyrme model, expanding in the collective coordinates variables, gives rise to second-class constraints. Recently this system was embedded in a more general Abelian gauge theory using the BFFT Hamiltonian method. in this work we quantize this gauge theory computing the Noether current anomaly using for this two different methods: an operatorial Dirac first class formalism and the non-local BV quantization coupled with the Fujikawa regularization procedure. (C) 2000 Elsevier B.V. B.V. All rights reserved.

Neutrinos in anomaly mediated supersymmetry breaking with R-parity violation

We show that a supersymmetric standard model exhibiting anomaly mediated supersymmetry breaking can generate naturally the observed neutrino mass spectrum as well mixings when we include bilinear R-parity violation interactions. In this model, one of the neutrinos gets its mass due to the tree-level mixing with the neutralinos induced by the R-parity violating interactions while the other two neutrinos acquire their masses due to radiative corrections. One interesting feature of this scenario is that the lightest supersymmetric particle is unstable and its decay can be observed at high energy colliders, providing a falsifiable test of the model.

Correlation between structural data and spectroscopic studies of a new beta-diketonate complex with trivalent europium and gadolinium

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Atmospheric cosmic rays in the South Atlantic anomaly region

To study the production and propagation of fast secondaries particles in the atmosphere, data collected during eleven quiet-time balloon flights are analysed. Comparisons of these data with those obtained in different geomagnetic rigidity regions permit to estimate the contributions of the proton and electron components in the measured intensities. Derivations of this last component in the «upward» and «downward» moving electrons fluxes indicate that in the anomaly region a fraction of these particles, produced by the primary protons, are leaving the atmosphere and will not return to the Earth. © 1991 Società Italiana di Fisica.