New constraints on ages of glasses proposed as reference materials for fission-track dating

New analyses have been performed in order to enhance the data-set on the independent ages of four glasses that have been proposed as reference materials for fission-track dating. The results are as follows. Moldavite - repeated (40)Ar/(39)Ar age determinations on samples from deposits from Bohemia and Moravia yielded an average of 14.34 +/- 0.08 Ma. This datum agrees with other recent determinations and is significantly younger than the (40)Ar/(39)Ar age of 15.21 +/- 0.15 Ma determined in the early 1980s. Macusanite (Peru) -four K-Ar ages ranging from 5.44 +/- 0.06 to 5.72 +/- 0.12 Ma have been published previously. New (40)Ar/(39)Ar ages gave an average of 5.12 +/- 0.04 Ma. Plateau fission-track ages determined using the IRMM-540 certified glass and U and Th thin films for neutron fluence measurements agree better with these new (40)Ar/(39)Ar ages than the previously published ages. Roccastrada glass (Italy) - a new (40)Ar/(39)Ar age, 2.45 +/- 0.04 Ma, is consistent with previous determinations. The Quiron obsidian (Argentina) is a recently discovered glass that has been proposed as an additional reference material for its high spontaneous track density (around 100 000 cm(-2)). Defects that might produce spurious tracks are virtually absent. An independent (40)Ar/(39)Ar age of 8.77 +/- 0.09 Ma was determined and is recommended for this glass. We believe that these materials, which will be distributed upon request to fission-track groups, will be very useful for testing system calibrations and experimental procedures.

Fission track and U-Pb in situ dating applied to detrital zircon from the Vale do Rio do Peixe Formation, Bauru Group, Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Micro-Raman spectroscopy and SEM/EDX applied to improve the zircon fission track method used for dating geological formations

The zircon mineral is widely studied in geochronology. In the case of the fission track method (FTM), the age is determined by the density of fission tracks at the zircon surface, which can be observed with an optical microscope after an appropriate chemical treatment (etching). The etching must be isotropic at the zircon grain surface to be used in the FTM, which leads those zircon grains whose etching is anisotropic to be discarded. The only reason for this discarding is the nonuniform morphology of the surface grain seen by optical microscopy, that is, no further physicochemical analysis is performed. In this work, combining micro-Raman and scanning electron microscopy (SEM) to study the etching anisotropy, it was shown that zircon grains that present at least one area at the surface where the density of fission track is uniform can be used in the FTM. The micro-Raman showed characteristic spectra of the standard zircon sample either from the areas where there are tracks or from where there are not. The only difference found was in the Raman bandwidths, which were broader for the areas with higher density of fission tracks. This suggests simply a decrease in the relative percentage of the crystalline/amorphous phases at these areas. The SEM/energy dispersive spectrometry (EDX) showed that there were no significant differences in the principal chemical composition at the areas with and without fission tracks. Copyright (c) 2008 John Wiley & Sons, Ltd.

Zircon fission track and U-Th-Pb in situ dating of Rio Parana Formation, Parana Basin, Brazil

Ages of zircon from sedimentary samples of Rio Parana Formation, belonging of Bauru Group, north of Parana Basin, Brazil, has been determined by zircon Fission Track and U-Th-Pb in situ dating methods. The obtained ages are from same zircon grain that provided information on the source areas for the sediments and the morphotectonic events.

New far-infrared laser lines from CH3OD methanol deuterated isotope

We report on a study of the CH3OD molecule in a search for new far-infrared (FIR) laser lines. For optical pumping of large offset vibrational absorption transitions, a continuous-wave waveguide CO2 laser with 300 MHz tunability around each line was used for the first time. As a consequence, 17. new far-infrared laser emissions were observed. For these lines, we also present data on wavelength, intensity, offset, relative polarization, and optimum operation pressure.

New laser lines from CHD2OH methanol deuterated isotope

Through the optical pump technique we have reinvestigated the CHD2OH molecule as a source of far-infrared (FIR) laser lines using for the first time a CO2 laser lasing on regular, hot, and sequence bands. As a consequence, we present here spectroscopic data of 16 now FIR laser transitions from this molecule. Furthermore, we also present a catalogue of all FIR laser lines generated from CHD2OH.

Traceability of bovine meat and bone meal in poultry by stable isotope analysis

Bovine meat and bone meal (MBM) was widely used in animal diets until outbreaks of Bovine Spongiform Encefalopathy (BSE) occurred in some countries. It has not been confirmed yet whether or not BSE may be transmitted to man through chicken meat originated from poultry that had been fed diets containing MBM. Therefore, consumers nowadays express preference for meat originated from birds fed exclusively vegetable diets. This study analyzed samples of major breast muscle (Pectoralis major) using mass spectrometry of stable isotopes (carbon and nitrogen) as a means to assess the presence of MBM in broiler diets, a technique that might be used in the certification of poultry quality. A total of 150 day-old chicks were reared in five randomized treatments with increasing MBM dietary inclusion levels (0, 1, 2, 4 and 8%). on day 42, breast muscle samples were collected from three birds per treatment and used in the determination of 13C/12C and 15N/14N isotope ratios. The breast muscle isotope values were expressed as delta in parts per thousand (delta ). The following carbon isotope values (13C) were found: 18.74 ±0.11, 18.51 ±0.19, 18.24 ±0.10, -17.79 ±0.12, and -17.15 ±0.15 for 0, 1, 2, 4 and 8% MBM dietary levels, respectively. Nitrogen isotope values (15N) were 1.65 ±0.14, 1.65 ±0.28, 1.72 ±0.08, 1.95 ±0.16, and 2.52 ± 0.09 for 0, 1, 2, 4 and 8% MBM dietary levels, respectively. This study showed important differences in delta13C and delta15N values in breast meat, evidencing a simultaneous enrichment of this isotopic pair, which allowed tracing MBM in bird diets. Analysis of carbon and nitrogen stable isotopes may be used to ensure feeding with exclusively vegetable diets, and might also be used as a reliable evaluation tool in broiler meat certification. The diet with 1% inclusion level of MBM and the exclusively vegetable diet showed similar results.

The traceability of animal meals in layer diets as detected by stable carbon and nitrogen isotope analyses of eggs

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

ESR dating of a subfossil shell from Couve Island, Ubatuba, Brazil

The occurrence of subfossil material in bottom sediments of Couve Island, Ubatuba region, São Paulo State, is confirmed. The analyzed material consists of a bivalve shell that was dated by the electron spin resonance technique. By the additive irradiation method an archaeological absorbed dose of (25 +/- 5) Gy was obtained and calibration with other dating works in the same area allows the inference of an age of (25 +/- 5) x 10(2) years. The importance of this finding and its paleoecological implications could contribute to elucidating the nature of short-term environmental changes in the Brazilian coastline during the Holocene, as well as becoming an important tool to the understanding of the distribution and biological aspects of the bivalve fauna. (C) 2002 Elsevier B.V. Ltd. All rights reserved.

Spatial variation in the strength of mutualism between a jumping spider and a terrestrial bromeliad: Evidence from the stable isotope N-15

Psecas chapoda, a neotropical jumping spider strictly associated with the terrestrial bromeliad Bromelia balansae in cerrados and semi-deciduous forests in South America, effectively contributes to plant nutrition and growth. In this study, our goal was to investigate if spider density caused spatial variations in the strength of this spider-plant mutualism. We found a positive significant relationship between spider density and delta N-15 values for bromeliad leaves in different forest fragments. Open grassland Bromeliads were associated with spiders and had higher delta N-15 values compared to forest bromeliads. Although forest bromeliads had no association with spiders their total N concentrations were higher. These results suggest that bromeliad nutrition is likely more litter-based in forests and more spider-based in open grasslands. This study is one of the few to show nutrient provisioning and conditionality in a spider-plant system. (c) 2008 Elsevier Masson SAS. All rights reserved.

Mixed-isotope Bose-Einstein condensates in rubidium

We consider the ground-state properties of mixed Bose-Einstein condensates of Rb-87 and Rb-85 atoms in the isotropic pancake trap for both signs of the interspecies scattering length. In the case of the repulsive interspecies interaction, there are the axially symmetric and symmetry-breaking ground states. The threshold for the symmetry-breaking transition, which is related to appearance of a zero dipole mode, is found numerically. For attractive interspecies interactions, the two condensates assume symmetric ground states for the numbers of atoms up to the collapse instability of the mixture.

Multivariate analysis of stable isotope data in the traceability process for birds

A análise isotópica tem se mostrado uma ferramenta de suma importância ao processo de rastreabilidade, no entanto, existem divergências nas análises estatísticas dos resultados, uma vez que os dados são dependentes e advindos de vários elementos químicos tais como Carbono, Hidrogênio, Oxigênio, Nitrogênio e Enxofre (CHON'S). Com o intuito de estabelecer a análise propícia para os dados de rastreabilidade em aves pela técnica de isótopos estáveis e avaliar a necessidade da análise conjunta das variáveis, foram usados dados de carbono-13 e de nitrogênio-15 de ovos (albúmen + gema) de poedeiras e músculo peitoral de frangos de corte, os quais foram submetidos à análise estatística univariada (Anova e complementada pelo teste de Tukey) e multivariada (Manova e Discriminante). Os dados foram analisados no software Minitab 16, e os resultados, consolidados na teoria, confirmam a necessidade de análise multivariada, mostrando também que a análise discriminante esclarece as dúvidas apresentadas nos resultados de outros métodos de análise comparados nesta pesquisa.

TL, OSL and C-14 dating results of the sediments and bricks from mummified nuns' grave

Este artigo apresenta os resultados de datação por TL e OSL de solos, e fragmentos de tijolos de um túmulo, que foi ocupado por duas freiras mumificadas encontradas no Mosteiro da Luz, localizado no Estado de São Paulo, Brasil. As idades encontradas por TL e OSL foram comparadas às obtidas a partir de C-14 dos colágenos contidos em amostras de osso das múmias. A maioria das idades obtidas são do século XVIII. A espectroscopia de radiação-gama foi utilizada para avaliar concentrações de radioisótopos naturais nas amostras e para calcular as taxas de dose anual que resultaram em 3,0 a 5,3 Gy/kano. As concentrações radioativas são próximas daquelas obtidas através de Análise por Ativação de Nêutrons. Os conteúdos de elementos U, Th e Ce são superiores aos encontrados na maioria dos sedimentos.

Carbon isotope analysis in apple nectar beverages

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