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Registros recuperados: 7
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Activation of bovine oocytes by strontium combined or not with an electric pulse Arq. Bras. Med. Vet. Zootec.
Leal,C.L.V.; Méo,S.C.; Garcia,J.M..
O objetivo deste trabalho foi avaliar as taxas de ativação e de clivagem de oócitos bovinos tratados com estrôncio (10mm de SrCl2), após maturação in vitro por 27-28 horas. No experimento 1, os tratamentos foram: S4 - ativação pelo estrôncio por 4 horas; S12 - ativação pelo estrôncio por 12 horas; S30 - ativação pelo estrôncio por 30 horas; e P - ativação por pulso elétrico (3 pulsos de 1,0kv/cm). No experimento 2 os tratamentos foram: PS4 - ativação combinada pelo pulso elétrico e pelo estrôncio por 4 horas; S4P - ativação pelo estrôncio por 4 horas e pelo pulso elétrico; e PS30 - ativação pelo pulso elétrico e pelo estrôncio por 30 horas. No experimento 1, todos os tratamentos apresentaram taxas similares de ativação (83-90%; P>0,05). Para clivagem, P...
Tipo: Info:eu-repo/semantics/other Palavras-chave: Cattle; Activation; Parthenogenesis; Oocyte; Strontium; Electric pulse.
Ano: 2003 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-09352003000300020
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Florisphaera profunda and the origin and diagenesis of carbonate phases in eastern Mediterranean sapropel units ArchiMer
Thomson, J; Crudeli, D; De Lange, Gj; Slomp, Cp; Erba, E; Corselli, C; Calvert, Se.
High relative concentrations of the lower photic zone nannofossil Florisphaera profunda have been reported in all recent eastern Mediterranean sapropels. In the most recent sapropel (S1), high bulk sediment Sr/Ca ratios occur along with high F. profunda contents toward the base of the unit, exemplified here in four cores from 1.5-3.5 km water depth. Co-occurring biogenic carbonates contain insufficient Sr to account for these high Sr concentrations, and X-ray diffraction and selective leaching show that the high Sr/Ca ratios are due to aragonite, the CaCO3 polymorph that is rarely preserved in deep marine sediments, with similar to1 wt % Sr. The possible sources of this aragonite include ( 1) precipitation with surface ocean production, ( 2) detrital input...
Tipo: Text Palavras-chave: Sapropel; Aragonite; Strontium.
Ano: 2004 URL: https://archimer.ifremer.fr/doc/00229/33975/32412.pdf
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Human mobility on the Brazilian coast: an analysis of strontium isotopes in archaeological human remains from Forte Marechal Luz Sambaqui Anais da ABC (AABC)
Bastos,Murilo Q. R; Souza,Sheila M. F. Mendonça de; Santos,Roberto V; Lima,Bárbara A. F; Santos,Ricardo V; Rodrigues-Carvalho,Claudia.
This study investigated strontium isotopes in the dental enamel of 32 human skeletons from Forte Marechal Luz sambaqui (shellmound), Santa Catarina, Brazil, aiming at identifying local and non-local individuals. The archeological site presents pot sherds in the uppermost archeological layers. Dental enamel was also examined from specimens of terrestrial fauna (87Sr/86Sr = 0. 71046 to 0. 71273) and marine fauna (87Sr/86Sr = 0. 70917). The 87Sr/86Sr isotope ratio for individuals classified as locals ranged from 0. 70905 to 0. 71064 and was closer to the isotope ratio of the seawater than to the ratio of the terrestrial fauna, indicating a strong influence of marine strontium on the inhabitants of this sambaqui. The results indicate the existence of three...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Brazil; Human mobility; Isotopes; Prehistory; Shellmounds; Strontium.
Ano: 2011 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652011000200030
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Silicate diagenesis in deep-sea sediments from the Tonga forearc (SW Pacific): a strontium and Rare Earth Elements signature ArchiMer
Vitali, F; Blanc, Gerard; Toulkeridis, T; Stille, P.
Sr-87/Sr-86 isotopic ratios, strontium and Rare Earth Element concentrations obtained on volcano-sedimentary rocks and separated clay mineral and zeolite fractions reveal a formation by pore water-volcanic rock interaction for most of the hydrous silicate minerals of the Site 841 ODP collected from the Tonga forearc. Unusual strontium concentrations and isotopic ratios recorded in the Miocene tuffs associated with specific REE patterns indicate that the formation of these hydrous silicates does not follow a simple burial diagenesis model, but was related to the cooling of intruding basaltic sills in the Miocene volcano-sedimentary series. Migration of strontium into the pore water in response to the heat flow induced the formation of Sr-bearing zeolites...
Tipo: Text Palavras-chave: Tonga; Silicates; Strontium; Terres rares; Diagenèse; Flux thermique; Tonga; Silicates; Strontium; Rare Earth Elements; Diagenesis; Heat flow.
Ano: 2000 URL: http://archimer.ifremer.fr/doc/00324/43563/44060.pdf
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Simultaneous use of strontium:calcium and barium:calcium ratios in otoliths as markers of habitat: Application to the European eel (Anguilla anguilla) in the Adour basin, South West France ArchiMer
Tabouret, Helene; Bareille, G.; Claverie, F.; Pecheyran, C.; Prouzet, Patrick; Donard, O. F. X..
Sr:Ca and Ba:Ca ratios in water from the Adour estuary show a clear relationship with the salinity of the surrounding water for salinities <20, while ratios are almost constant above this level of salinity. A Positive relationship was observed for the Sr:Ca ratio, whereas it was inverse for the Ba Ca ratio. These two elemental ratios were measured in the otoliths of the European eels (Anguilla anguilla L) using femtosecond laser ablation linked to an ICP-MS (fs-LA ICP-MS) There was a direct relationship between the elemental ratios recorded in eel otoliths and those found in water from fresh and marine areas, suggesting that Sr Ca and Ba:Ca ratios in eel otoliths can be used as markers of habitat in this estuary Continuous profiling allowed the...
Tipo: Text Palavras-chave: Otoliths; Anguilla anguilla; Estuaries; Water chemistry; Strontium; Barium; Laser ablation; Inductively coupled plasma mass spectrometer.
Ano: 2010 URL: http://archimer.ifremer.fr/doc/00009/11990/9042.pdf
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Thermochemistry of strontium incorporation in aragonite from atomistic simulations OceanDocs
Grau-Crespo, R.; Ruiz-Hernández, S. E.; Ruiz-Salvador, A. R.; De Leeuw, N. H..
We have investigated the thermodynamics of mixing between aragonite (orthorhombic CaCO3) and strontianite (SrCO3). In agreement with experiment, our simulations predict that there is a miscibility gap between the two solids at ambient conditions. All SrxCa1 xCO3 solids with compositions 0.12 < x < 0.87 are metastable with respect to separation into a Ca-rich and a Sr-rich phase. The concentration of Sr in coral aragonites (x 0.01) lies in the miscibility region of the phase diagram, and therefore formation of separated Sr-rich phases in coral aragonites is not thermodynamically favorable. The miscibility gap disappears at around 380 K. The enthalpy of mixing, which is positive and nearly symmetric with respect to x = 0.5, is the dominant...
Tipo: Journal Contribution Palavras-chave: 1246; Aragonite; Coral reefs; Thermodynamic activity; Strontium; Strontium.
Ano: 2010 URL: http://hdl.handle.net/1834/4103
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Whitemouth croaker, Micropogonias furnieri, trapped in a freshwater coastal lagoon: a natural comparison of freshwater and marine influences on otolith chemistry Neotropical Ichthyology
Albuquerque,Cristiano Q. de; Miekeley,Norbert; Muelbert,José H..
Strontium and barium incorporation into otoliths was compared between whitemouth croaker, Micropogonias furnieri, collected from an entrapped freshwater population (Mirim Lagoon) and a normal marine/estuarine population in southern Brazil. Chemical analysis was performed using LA-ICPMS with the objective of validating the effects of marine and freshwater environments on Sr and Ba incorporation as a basis for further investigation of marine and freshwater connectivity of M. furnieri. The freshwater population was dominated by older fish with mean ±SD age of 34±1 y, whereas the coastal samples were dominated by younger fish of 14±7 y. Comparison of strontium and barium incorporation among otolith life-history profiles indicated significantly higher barium...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Strontium; Barium; Laser ablation; ICPMS; Life-history; Population extinction.
Ano: 2010 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252010000200009
Registros recuperados: 7
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