Letteratura scientifica selezionata sul tema "Isotopes du Soufre et du Calcium"
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Articoli di riviste sul tema "Isotopes du Soufre et du Calcium":
Bejaoui, J., S. Bouhlel, D. Barca e A. Braham. "Le champ filonien à Zn-(Pb, Cu, As, Hg) du district minier de Fedj Hassène (Nord Ouest de la Tunisie): Minéralogie, Eléments en traces, Isotopes du Soufre et Inclusions Fluides". Estudios Geológicos 67, n. 1 (30 giugno 2011): 5. http://dx.doi.org/10.3989/egeol.40214.118.
André-Mayer, Anne-Sylvie, Jacques L. Leroy, Éric Marcoux e Catherine Lerouge. "Inclusions fluides et isotopes du soufre du gisement Cu–Au de Valea Morii (monts Apuseni, Roumanie) : un télescopage porphyre–épithermal neutre ?" Comptes Rendus de l'Académie des Sciences - Series IIA - Earth and Planetary Science 333, n. 2 (luglio 2001): 121–28. http://dx.doi.org/10.1016/s1251-8050(01)01611-1.
Nadif, M., e C. Gatellier. "Influence d'une addition de calcium ou de magnésium sur la solubilité de l'oxygène et du soufre dans l'acier liquide". Revue de Métallurgie 83, n. 5 (maggio 1986): 377–94. http://dx.doi.org/10.1051/metal/198683050377.
MESCHY, F., e L. GUÉGUEN. "Alimentation des vaches laitières : comparaison des recommandations d’apports en minéraux". INRAE Productions Animales 5, n. 4 (29 ottobre 1992): 283–88. http://dx.doi.org/10.20870/productions-animales.1992.5.4.4242.
Ferdinand, Yao Diby, Assale Fori Jean Paul, Alla Amani Jonas e Digbehi Zeli Bruno. "Caracterisasion Geochimique des Deblais du Substratum de la Baie du Banco, Abidjan, Basse Cote d‘Ivoire". European Scientific Journal, ESJ 19, n. 36 (31 dicembre 2023): 124. http://dx.doi.org/10.19044/esj.2023.v19n36p124.
Gordon, Gwyneth W., Jorge Monge, Melanie B. Channon, Qing Wu, Joseph L. Skulan, Ariel D. Anbar e Rafael Fonseca. "Calcium Isotopic Composition and Its Association With Multiple Myeloma Disease Activity". Blood 122, n. 21 (15 novembre 2013): 3157. http://dx.doi.org/10.1182/blood.v122.21.3157.3157.
Reynard, L. M. "Erratum to Reynard, L.M., Henderson, G.M. and Hedges, R.E.M. (2010) Calcium isotopes in human and animal bone, Geochimica et Cosmochimica Acta 74, 3735–3750". Geochimica et Cosmochimica Acta 75, n. 8 (aprile 2011): 2234–35. http://dx.doi.org/10.1016/j.gca.2011.02.005.
Chirackal, Sinto Sebastian, Esteban Braggio, Yuan Xiao Zhu, Chang-Xin Shi, Scott Van Wier, Gregory Ahmann, Veronica Gonzalez-Calle et al. "Lenalidomide Inhibits Thioredoxin Reductase (TrxR) in Multiple Myeloma (MM) Cells but Direct Inhibition of Trxr and Thioredoxin (Trx) Can Bypass Requirement of Cereblon (CRBN)". Blood 128, n. 22 (2 dicembre 2016): 4482. http://dx.doi.org/10.1182/blood.v128.22.4482.4482.
Gonzalez-Calle, Veronica, Abigail Slack, Susan Luft, Kathryn Pearce, Rhett P. Ketterling, Tania Jain, Sinto Sebastian Chirackal et al. "Evaluation of Revised International Staging System for Transplant-Eligible Multiple Myeloma Patients". Blood 128, n. 22 (2 dicembre 2016): 3452. http://dx.doi.org/10.1182/blood.v128.22.3452.3452.
Jain, Tania, Hemalatha Narayanasamy, Joseph Mikhael, Craig B. Reeder, P. Leif Bergsagel, Angela Mayo, A. Keith Stewart, Farouk Mookadam e Rafael Fonseca. "Reversible Cardiotoxicity Associated with Carfilzomib Use in Patients with Multiple Myeloma". Blood 128, n. 22 (2 dicembre 2016): 2126. http://dx.doi.org/10.1182/blood.v128.22.2126.2126.
Tesi sul tema "Isotopes du Soufre et du Calcium":
Jouini, Arbia. "Perturbations biogéochimiques à la limite Crétacé-Paléogène : apport des isotopes du Soufre et du Calcium". Electronic Thesis or Diss., Université de Lorraine, 2023. http://www.theses.fr/2023LORR0065.
The Cretaceous-Paleogene boundary (KPg, -66 Ma) is associated to one of the deepest biogeochemical cycle disruptions in Earth's recent history. The events associated to the KPg boundary include one of the strongest known oceanic calcareous bioproduction crisis and are coeval with a bolid impact (that formed the Chixculub crater) and the emplacement of a Large Igneous Province (Deccan traps). Many studies investigated the mechanism(s) triggering the environmental perturbations and many questions remain unanswered regarding the relative contribution of the volcanic event and the impact on the KPg crisis. Yet, modification of the ocean-atmosphere system composition through massive input of sulfuric and carbonic acid very likely played a key, underconstrained, role.During this thesis project, I conducted high-resolution stable sulphur and calcium isotope records across the Cretaceous-Paleogene transition. These records are based on monospecific samples of planktonic and benthic foraminifera from the equatorial Pacific.The benthic and planktonic δ44/40Ca records before and after the K-Pg boundary allowed us to demonstrate a succession of episodes of ocean alkalinity change related to the increase in continental weathering and the biocalcification crisis caused by CO2 emissions from Deccan volcanism. Carbonate compensation through dissolution of carbonate sediments, reduction of biocalcification and/or increase in continental weathering had to occur to compensate for the excess CO2. As a result, this led to rapid changes in oceanic carbonate chemistry, in combination with a reduction in the export of surface alkalinity in response to the early Paleogene planktonic biomineralisation crisisExamination of sulphur cycle disruption instead supports the idea that mass extinction through the K-Pg transition is not associated with a global expansion of anoxic conditions, in contrast to the various Phanerozoic mass extinction events, where there are multiples evidences for the development of anoxic conditions associated with carbon cycle disruption. These findings are consistent with micropalaeontological observations that show no benthic foraminiferal mass extinction.This multi-proxy geochemical approach has the advantage of allowing a more detailed assessment of key parameters such as carbonate chemistry and oceanic anoxia across the Cretaceous-Paleogene transition, thus providing a clearer global picture of biogeochemical perturbations around this time
Labidi, Jabrane. "Origine, dynamique et multi-compositions isotopiques du soufre dans le manteau terrestre". Paris 7, 2012. http://www.theses.fr/2012PA077165.
Sulfur content and isotope composition of the terrestrial mantle can provide major constraints on the internal dynamic of this element and on nature of mantle heterogeneities. The mean S isotope composition of this reservoir can also characterize the potentiel mantle-core equilibrium and hence help to decipher the question of sulfur origin on Earth. In this study, we report S content and relative abundances of 32S, 33S, 34S and 36S in more than 120 glassy basalts coming from 3 ocean ridges and a transform fault. We propose a new sulfur extraction protocol for silicate glasses based on hydrofluoric acid. We evidenced an analytical bias affecting the previously published dataset, probably due to the use of the e"Kiba reagent". The redetermined δ34S are approximately 1‰ lower than the previously published data. We also provide the first Δ33S and Δ36S data for ocean ridge basalts. These date are, within uncertainty, indistinguishable from our CDT estimate, confirming the idea that terrestrial mantle has a Δ33S and Δ36S close to 0. 000‰ with respect to this international standard. The δ34S variability encompasses a 3‰ range in ocean ridge basalts and correlations between O34S and radiogenic isotopes demonstrate that S isotopes are tracers of mantle heterogeneities. On the other hand, the mean δ34S of MORB mantle is -0,80 ± 0,38‰, significantly lower than the chondritic value of 0,04 ± 0,31‰. The Pb-S isotope systematic in Pacific Antarctic basalts indicates that recycled oceanic crust bears a positive δ34S. As a corrollary, this result implies that the depleted part of the mantle is even more negative thant the mean MORB value. We propose a δ34S value of -1,40 ± 0,20‰ for this reservoir. In South Atlantic basalts, the δ34S are correlated with Sr isotopes, trends being consistent with recycled sediment feeding the mantle source of these basalts. Taken together, the δ34S variability associated to the Δ33S and Δ36S constancy indicates that the recycled components are a post-archean age, in agreement with independant estimation of their mean age using Pb isotopes. Finally, the negative δ34S of MORB mantle can be reconcilied only with a mantle-core equilibrium, implying an internal origin of sulfur as opposed to a late origin
Valdes, Maria. "Geochemistry and Cosmochemistry of Calcium Stable Isotopes". Doctoral thesis, Universite Libre de Bruxelles, 2018. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/276866.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished
Schmitt, Anne-Désirée. "Les isotopes du calcium : Développements analytiques.Application au bilan océanique présent et passé". Université Louis Pasteur (Strasbourg) (1971-2008), 2003. http://www.theses.fr/2003STR13077.
First, a measurement protocol was developed at the Centre de Géochimie de la Surface to avoid instrumental fractionation. After chemical separation on ion exchanging resins, the Ca isotopic compositions were measured on a thermo-ionisation mass spectrometer, using a double-spike technique. The Ca isotopic ratios were expressed in a delta notation. To do this, a reference material is needed. No international standard presently exists for Ca isotopes. For that reason, we proposed to use the SRM 915a carbonaceous standard from the NIST. Seawater, the only common sample of most of previous studies has also been used: it was calibrated against the carbonaceous standard and used in present study. This protocol was then applied to study the Ca oceanic budget. The isotope data of continental waters allowed to constrain the Ca flux to the ocean. A limited variability of d44Ca (0. 5 ) was recorded at the outlet of main rivers or for hydrothermal vents. Moreover, no relationship was observed between d44Ca and the lithology or the climate of the studied watersheds. This allowed to determine the mean Ca isotopic composition of the Ca flux to the ocean (-1. 1 ± 0. 2 ) and to suggest that this value remains rather constant through time. A consequence of this value is that present-day seawater is at steady-state with regard to Ca isotopes. The d44Ca study of marine phosphates from Miocene and Pleistocene, which reflect the paleo-seawater variations through time, has shown that this was not necessarily the case in the past. At 22 Ma, a deviation in d44Ca through more positive values suggests that the intensity of the incoming and outcoming fluxes changed, but not their isotopic composition
Méhay, Sabine. "Etude de pétroles biodégradés : L'isotopie du soufre comme outil de corrélation et marqueur de processus d'altération". Université Louis Pasteur (Strasbourg) (1971-2008), 2006. https://publication-theses.unistra.fr/public/theses_doctorat/2006/MEHAY_Sabine_2006.pdf.
In the present study, the biodegradation of petroleum in reservoirs has been investigated by the molecular and isotopic study of three series of petroleum and core extracts, coming from Alberta (Canada), from the Potiguar Basin (Brazil) and from the San Joaquim Valley (California, USA). The molecular study allowed us to rank them according to the biodegradation scale of Peters and Moldowan (1993). This study also showed variations in the level of maturity reached by the samples and in the origin of the organic matter, within each series. However, correlations between oil samples as well as the identification of their source rocks appeared difficult to establish, due to the biodegradation of biomarkers. The sulfur isotopic study of oil samples showed that the 34S constitutes a good correlation tool because it does not seem to be affected by the biodegradation of sulfur organic compounds. However, this work suggested that secondary reactions of sulfur exchange and/or incorporation could happen with increasing biodegradation, and lead to variations in the sulfur isotopic composition of oil, in reservoirs containing H2S, generated notably by bacterial sulphate reduction. This was further corroborated by laboratory experiments of simulation. Finally, tests for the development of irm-GC/MS to measure the sulfur isotopic composition of individual compounds were performed in order to progress in the study of the sulfurization processes of organic matter
Baroni, Mélanie. "Etude des anomalies isotopiques du soufre et de l'oxygène dans le sulfate d'origine volcanique enregistré dans les archives glaciaires". Université Joseph Fourier (Grenoble), 2006. http://www.theses.fr/2006GRE10121.
Plinian volcanism modify climate for several years by injecting large quantities of sulfur dioxide directly into the stratosphere, further oxidized to sulfuric acid droplets which reflect solar radiations and change the radiative properties of the atmosphere. Up to now, the study of volcanic signals preserved in glaciological archives was limited to the measurements of sulfate concentrations. We propose the use of new tools which are the sulfur and oxygen isotopic anomalies of volcanic sulfate recorded in Dome C and South Pole, to provide further insights into past volcanism. A study of the temporal evolution of the sulfur and oxygen isotopic anomalies in the Agung (March 1963) and the Pinatubo (June 1991) volcanic sulfate, has been conducted. The sulfur isotopic anomaly changes in sign with time from an initial positive component to a negative value. This change in sign is accompanied by a significant depletion of heavy isotopes with time. Sulfur isotopic anomaly is created during sulfur dioxide photochemical oxidation to sulfuric acid on a month time scale, indicative of a fast process. The oxygen isotopic anomaly seems to be linked to the quasi-biennal oscillation of the stratosphere. Twelve volcanic eruptions have been studied over the last millenium, by taking the whole sulfate signal. Sulfur isotopic anomaly allowed the identification of 6 stratospheric volcanic eruptions revealing the power of this tool when the nature of the eruption is unknown
Kitayama, Yumi. "Les quatre isotopes du soufre dans les kimberlites de Sibérie, traceurs du recyclage de croûte océanique et de sédiments Archéens dans le manteau terrestre". Electronic Thesis or Diss., Université de Lorraine, 2018. http://www.theses.fr/2018LORR0244.
Inherited from the early atmosphere, anomalies in the relative abundances of sulfur isotopes (32S, 33S, 34S and 36S) are recorded in sediments older than 2.5 billion year (i.e. Archean). Here we test the robustness of sulfur isotopes to trace the early recycling of oceanic crust and sediments that may have been transferred to the deep mantle or stored in the lithospheric mantle since the onset of subduction. In Siberia, the lithospheric mantle has been naturally sampled by the Udachnaya-East kimberlite while it was erupting. Because it is extremely well preserved, rich in Na, K, Cl, S and contains remnants of oceanic crust recycled during the Archean, this kimberlite enables us to test : (1) the hypothesis of an early recycling of Archean atmospheric sulfur in the lithospheric mantle and/or the deeper source of the kimberlite; (2) the coherence between in situ (SIMS in sulfide minerals) and bulk methods (chemical extraction of sulfur from powdered rocks, followed by gas source mass-spectrometry) for measuring multiple sulfur isotopes. Our results, combined with measurements of Rb-Sr, Sm-Nd and lead (204Pb, 206Pb, 207Pb, 208Pb) isotopes, show that: (1) sulfates from the Udachnaya-East kimberlite and its nodules composed of chloride-carbonate have a deep, magmatic origin, uncontaminated by host sediments, suggesting the presence of sulfate-rich, oxidized domains in the mantle; (2) measurements of sulfur isotopes by bulk methods are consistent with the sulfide populations observed in situ; (3) sulfides from salty kimberlites are depleted in 34S with respect to the chondritic value and record small anomalies in sulfur isotopes ; (4) sheared peridotites contain another population of sulfides that are depleted in 34S and preserve 33S and 36S anomalies inherited from the Archean surface, despite resetting of the U-Pb chronometer during kimberlite eruption
Kitayama, Yumi. "Les quatre isotopes du soufre dans les kimberlites de Sibérie, traceurs du recyclage de croûte océanique et de sédiments Archéens dans le manteau terrestre". Thesis, Université de Lorraine, 2018. http://www.theses.fr/2018LORR0244.
Inherited from the early atmosphere, anomalies in the relative abundances of sulfur isotopes (32S, 33S, 34S and 36S) are recorded in sediments older than 2.5 billion year (i.e. Archean). Here we test the robustness of sulfur isotopes to trace the early recycling of oceanic crust and sediments that may have been transferred to the deep mantle or stored in the lithospheric mantle since the onset of subduction. In Siberia, the lithospheric mantle has been naturally sampled by the Udachnaya-East kimberlite while it was erupting. Because it is extremely well preserved, rich in Na, K, Cl, S and contains remnants of oceanic crust recycled during the Archean, this kimberlite enables us to test : (1) the hypothesis of an early recycling of Archean atmospheric sulfur in the lithospheric mantle and/or the deeper source of the kimberlite; (2) the coherence between in situ (SIMS in sulfide minerals) and bulk methods (chemical extraction of sulfur from powdered rocks, followed by gas source mass-spectrometry) for measuring multiple sulfur isotopes. Our results, combined with measurements of Rb-Sr, Sm-Nd and lead (204Pb, 206Pb, 207Pb, 208Pb) isotopes, show that: (1) sulfates from the Udachnaya-East kimberlite and its nodules composed of chloride-carbonate have a deep, magmatic origin, uncontaminated by host sediments, suggesting the presence of sulfate-rich, oxidized domains in the mantle; (2) measurements of sulfur isotopes by bulk methods are consistent with the sulfide populations observed in situ; (3) sulfides from salty kimberlites are depleted in 34S with respect to the chondritic value and record small anomalies in sulfur isotopes ; (4) sheared peridotites contain another population of sulfides that are depleted in 34S and preserve 33S and 36S anomalies inherited from the Archean surface, despite resetting of the U-Pb chronometer during kimberlite eruption
Cobert, Florian. "Processus et mécanismes physico-chimiques et biologiques responsables du fractionnement des isotopes du calcium". Phd thesis, Université de Strasbourg, 2012. http://tel.archives-ouvertes.fr/tel-00762532.
Boucher, Agnès. "Solubilisation et transfert des fertilisants et des phytosanitaires soufrés dans la zone non saturée sous le vignoble champenois : approche chimique et isotopique". Reims, 2002. http://www.theses.fr/2002REIMS019.
Treatments of vines in Champagne contaminate solute of the unsaturated zone. This work aims at identifying the origins and fate of degradation products derived from fertilizers and pesticides, using time variations of sulfates concentrations vertical profiles and determination of d18O and d34S under different parcels. D34S of the main source of sulfur (fertilizers, elementary sulfur, pyrites) are well distinguished. The fertilizers and pesticides solubilization don't lead to an isotopic fractionation between the source compound and the derived sulfate. Moreover, sulfates don't interact with chalk. Sulfates indicate the advance of fertilizers and pesticides degradation products. They migrate according a convection/diffusion flow