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| Mougel, Berengere; Moreira, Manuel; Agranier, Arnaud. |
| We investigate in details helium isotope data reported in Mougel et al. (2014) for 14 basaltic samples collected on the East Pacific Rise by submersible (15 degrees 4N) where the ridge interacts with the Mathematician seamounts. Samples locations are separated by only few hundred meters across a 15km along-axis profile. The data reveal a strong geochemical variability that has never been observed at such high spatial resolution for helium isotope compositions. Moreover, they reveal an unusually high He-4/He-3 mantle component also characterized by unradiogenic lead, atypical in oceanic basalts. He-Pb systematics suggests a mixture between a nonradiogenic lead and radiogenic helium pyroxenitic component, recycled from the deep continental lithosphere and... |
| Tipo: Text |
Palavras-chave: Helium; Isotopes; Mantle geochemistry; MORB; Hot spot; EPR. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00639/75140/75500.pdf |
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| Maia, Claudia Maria Branco de Freitas; Fukamachi, Cristiane Regina Budziak; Cambronero, Yorleni Chang; Dedecek, Renato Antônio; Mangrich, Antônio Sálvio; Narimoto, Kelly Mayumi; Milori, Débora M.B.P.; Simões, Marcelo Luiz. |
| The understanding of soil carbon stabilization processes can be very useful in the development of mitigation techniques for CO2 emissions and global warming. The greater the hydrophobicity of soil organic matter the more stabilized soil organic carbon. Therefore, hydrophobicity can be a sensitive index to characterizethe ‘quality’ of soil organic matter. In this context, the present work aimed to characterize the chemical structures of humic acids collected at three different depths in a hydrophobic Entisol (Neossolo) under loblolly plantation. The results of spectroscopic and chemical analyses (UV-Vis, fluorescence, EPR and X-ray diffractometry) indicated that, as soil depth increased, so did the content of conjugated organic structures, aromatic... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Humic acids; Water repellency; Forest soil; Fluorescence; EPR; X-ray. Solos florestais; Repelência à água; RPE; Fluorescência; Raio-X.. |
| Ano: 2010 |
URL: http://pfb.cnpf.embrapa.br/pfb/index.php/pfb/article/view/86 |
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| Walls, Margaret. |
| Extended producer responsibility (EPR) embodies the notion that producers should be made physically or financially responsible for the environmental impacts their products have at the end of product life. The EPR concept has taken hold in Europe and is garnering wide interest in the United States, where a variant known as "shared product responsibility" or "product stewardship" is usually the preferred approach. There are several policy instruments that are consistent with EPR-product take-back mandates, advance disposal fees, deposit-refunds, recycled content standards, and more. The EPR concept itself, however, provides little guidance about which of these instruments might be appropriate under particular conditions and for particular products. Moreover,... |
| Tipo: Working or Discussion Paper |
Palavras-chave: EPR; Recycling; Design for environment; Agricultural and Food Policy; Q2; H2. |
| Ano: 2003 |
URL: http://purl.umn.edu/10855 |
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| Silva,Alexandre Christofaro; Torrado,Pablo Vidal; Pérez,Martha González; Martin Neto,Ladislau; Vasquez,Felipe Macias. |
| O acúmulo e a estabilidade da matéria orgânica do solo estão relacionados com a declividade de vertentes. Por essa razão, foram avaliadas quantitativamente relações entre a declividade e o grau de humificação de ácidos húmicos, o conteúdo de fragmentos de carvão e suas idades radiocarbônicas. Foram amostrados quatro Latossolos situados nas posições de topo, ombro, meia encosta e sopé de uma toposseqüência com pastagens, de uma área cratônica do Sul de Minas Gerais. Os Latossolos são originados de gnaisses do Complexo Cristalino, da Era Pré-Cambriana, e apresentam regime hídrico údico e regime térmico isotérmico. Foram coletadas amostras de horizontes e sub-horizontes dos quatro perfis, para caracterização química e física, extração de ácidos húmicos e... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Ácidos húmicos do solo; Carvão do solo; Grau de humificação; EPR; Datação radiocarbônica. |
| Ano: 2007 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832007000500022 |
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| WATANABE,SHIGUEO; CANO,NILO F.; RAO,T.K. GUNDU; SILVA-CARRERA,BETZABEL N.; CARMO,LUCAS S.; QUINA,ANTONIO J.A.; GENNARI,ROSELI F.; MUNITA,CASIMIRO S.; AYALA-ARENAS,JORGE S.; FERNANDES,BRUNO G.. |
| ABSTRACT A cylindrical fragment of stalagmite from Caverna do Diabo, State of São Paulo, Brazil, has been studied and dated by thermoluminescence and electron paramagnetic resonance techniques. The thermoluminescence glow curves of stalagmite samples and subsequently gamma irradiated, have shown rise of three peaks at 135, 180 and 265 °C. From electron paramagnetic resonance spectra of stalagmite was possible to clearly identify three paramagnetic centers in the g = 2.0 region: Centers I, II and III are due to , and , respectively. The additive method was applied to calculate the accumulated dose using thermoluminescence peak at 265 °C and the electron paramagnetic resonance signal at g = 1.9973 of CO- 2 radical. The ages of the different slices of... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Stalagmite; Caverna do Diabo; Dating; TL; EPR. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652016000602137 |
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| KINOSHITA,ANGELA; SULLASI,HENRY L.; ASFORA,VIVIANE K.; AZEVEDO,RENATA L.; GUZZO,PEDRO; GUIDON,NIEDE; FIGUEIREDO,ANA MARIA G.; KHOURY,HELEN; PESSIS,ANNE-MARIE; BAFFA,OSWALDO. |
| ABSTRACT This work reports the dating of a fossil human tooth and shell found at the archaeological site Toca do Enoque located in Serra das Confusões National Park (Piauí, Brazil). Many prehistoric paintings have been found at this site. An archaeological excavation unearthed three sepulchers with human skeletons and some shells. Two Brazilian laboratories, in Ribeirão Preto (USP) and Recife (UFPE), independently performed Electron Spin Resonance (ESR) measurements to date the tooth and the shell and obtain the equivalent dose received by each sample. The laboratories determined similar ages for the tooth and the shell (~4.8 kyBP). The results agreed with C-14 dating of the shell and other samples (charcoal) collected in the same sepulcher. Therefore,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Dating; ESR; EPR; Shell; Tooth; Enamel.. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652016000300847 |
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