Journal articles on the topic 'S isotopes'
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1
Rossete, Alexssandra Luiza Rodrigues Molina, Josiane Meire Toloti Carneiro, Carlos Roberto Sant Ana Filho, and José Albertino Bendassolli. "Isotope determination of sulfur by mass spectrometry in soil samples." Revista Brasileira de Ciência do Solo 36, no. 6 (December 2012): 1787–93. http://dx.doi.org/10.1590/s0100-06832012000600012.
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Sulphur plays an essential role in plants and is one of the main nutrients in several metabolic processes. It has four stable isotopes (32S, 33S, 34S, and 36S) with a natural abundance of 95.00, 0.76, 4.22, and 0.014 in atom %, respectively. A method for isotopic determination of S by isotope-ratio mass spectrometry (IRMS) in soil samples is proposed. The procedure involves the oxidation of organic S to sulphate (S-SO4(2-)), which was determined by dry combustion with alkaline oxidizing agents. The total S-SO4(2-) concentration was determined by turbidimetry and the results showed that the conversion process was adequate. To produce gaseous SO2 gas, BaSO4 was thermally decomposed in a vacuum system at 900 ºC in the presence of NaPO3. The isotope determination of S (atom % 34S atoms) was carried out by isotope ratio mass spectrometry (IRMS). In this work, the labeled material (K2(34)SO4) was used to validate the method of isotopic determination of S; the results were precise and accurate, showing the viability of the proposed method.
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Lu, Dawei, Tuoya Zhang, Xuezhi Yang, Peng Su, Qian Liu, and Guibin Jiang. "Recent advances in the analysis of non-traditional stable isotopes by multi-collector inductively coupled plasma mass spectrometry." Journal of Analytical Atomic Spectrometry 32, no. 10 (2017): 1848–61. http://dx.doi.org/10.1039/c7ja00260b.
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Non-traditional stable isotopes, with no clear definition yet, generally refer to isotopes beyond C, H, O, N, and S with small variations in natural stable isotopic compositions, such as isotopes of transition and heavy metal elements.
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Ogbesejana, Abiodun Busuyi, Bo Liu, and Mehdi Ostadhassan. "Stable Isotope Geochemistry of the Organic Elements within Shales and Crude Oils: A Comprehensive Review." Molecules 27, no. 1 (December 22, 2021): 34. http://dx.doi.org/10.3390/molecules27010034.
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Over time, stable isotopes have proven to be a useful tool in petroleum geochemistry. However, there is currently insufficient literature on stable isotope geochemistry of the organic elements within shales and crude oils in many petroleum systems around the world. As a result, this paper critically reviews the early and recent trends in stable isotope geochemistry of organic elements in shales and crude oils. The bulk and compound-specific stable isotopes of H, C, and S, as well as their uses as source facies, depositional environments, thermal maturity, geological age, and oil–oil and oil–source rock correlation studies, are all taken into account. The applications of the stable isotopes of H and C in gas exploration are also discussed. Then, the experimental and instrumental approaches to the stable isotopes of H, C, and S, are discussed.
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Gaigalas, Algirdas, and Stanislaw Halas. "Stable Isotopes (H, C, S) and the Origin of Baltic Amber." Geochronometria 33, no. -1 (January 1, 2009): 33–36. http://dx.doi.org/10.2478/v10003-009-0001-9.
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Stable Isotopes (H, C, S) and the Origin of Baltic Amber New results of isotope analysis of light elements (H, C and S) of a dozen Baltic amber samples are described and discussed. Carbon isotope composition was nearly constant (ca. -23‰), whereas sulphur and hydrogen varied in their isotope compositions from +4 to -28‰ and from -171 to -213‰, respectively. The formation and subsequent evolution of this material since its origin in Paleogene time until present is outlined.
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Barrick, Reese E. "Isotope Paleobiology of the Vertebrates: Ecology, Physiology, and Diagenesis." Paleontological Society Papers 4 (October 1998): 101–37. http://dx.doi.org/10.1017/s1089332600000413.
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Isotopic studies of vertebrate material have a short history, while isotopic analyses of invertebrates originated in the 1940's. Interestingly, the driving force behind Harold Urey's desire to derive a carbonate paleotemperature scale in the 1940's and 1950's was the hope that it would solve the mystery of dinosaur extinction by demonstrating temperature changes at the K/T boundary. The most useful and commonly investigated stable isotopes for paleobiologic studies of vertebrates are carbon, nitrogen and oxygen. Oxygen is available from the inorganic bone or tooth apatite phase. Carbon is most often derived from tooth enamel carbonate or organic collagen, and nitrogen is derived from collagen. Each of these stable isotopes provides information on different aspects of an animal's biology and when combined, provide powerful analyses for ecological and evolutionary reconstructions. In the 1970's, much work was done describing the carbon and nitrogen variations in plants. This period was followed in the late 1970's and early 1980's by research on these isotopic variables in mammals (e.g., DeNiro and Epstein, 1978, 1981; Vogel, 1978; Van der Merwe, N.J., 1982). The utility of these isotopes for dietary recognition led to their extensive investigation in archeological studies. Not until the mid to late 1980's and 1990's have these isotopes been utilized in both the inorganic component of teeth and bones as well as the organic component of bones in Pleistocene and older paleobiologic studies. The 1980's also saw the emergence of research on the oxygen isotopic variations in mammals. However, the focus of isotopic studies on vertebrates was not for paleobiologic purposes, but rather, for attempts to derive paleohydrologic or paleoclimatic information from them (e.g., Longinelli, 1984; Luz et al., 1984).
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Benbow, Timothy J., Alan R. Hayman, Robert Van Hale, and Russell Frew. "Preparation of aqueous fatty acids for hydrogen and carbon stable isotope analysis by solid phase extraction." Marine and Freshwater Research 64, no. 4 (2013): 294. http://dx.doi.org/10.1071/mf12192.
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Stable isotope analyses of fatty acids in environmental waters provides important information as to their source(s). Analysis is often confounded due to low concentrations of fatty acids and/or a complex sample matrix requiring separation of the target analyte. The purpose of this study was to validate a method to extract fatty acids from natural waters using solid phase extraction (SPE) before compound specific isotope analysis (CSIA). Three SPE cartridges and multiple eluting solvents were tested to determine the efficiency, isotopic fractionation, and reproducibility of each extraction technique. Our results indicated that surface-modified styrene divinylbenzene cartridges, when eluted with methanol, caused negligible fractionation of the hydrogen isotopes and minimal fractionation of the carbon isotopes, but that isotopic fractionation occurred when compounds were only partially eluted from SPE cartridges. Compounds were also extracted from landfill leachate using both SPE and liquid–liquid extraction (LLE). The hydrogen isotope composition (δ2H) of compounds extracted from water using either method were within experimental precision and the carbon isotope composition (δ13C) of all but one fatty acid were within experimental precision. Therefore, these experiments prove the aforementioned SPE methods to be a convenient and precise method to extract fatty acids from natural waters before CSIA.
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Miller, J. J., G. J. Beke, S. Pawluk, and H. R. Krouse. "Sulfur and oxygen isotopic composition of sulfates at two saline sites in southern Alberta." Canadian Journal of Soil Science 73, no. 4 (November 1, 1993): 633–37. http://dx.doi.org/10.4141/cjss93-061.
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Possible sources of SO4 in soil, drift and bedrock at two saline sites in southern Alberta were investigated using sulfur and oxygen isotope analyses. Slight differences (0.6–5.2 per mil) between δ34S values of SO4 and insoluble S in the geologic material were attributed to kinetic fractionation during oxidation of organic S. Negative δ18O values of SO4 in the shallow (<6 m) bedrock, drift and soil reflected oxidation of reduced S. In contrast, positive δ18O values in the deep (>6 m) bedrock indicated sulfate reduction. The exact source of SO4 could not be determined in this preliminary study. The isotope approach, however, shows promise and warrants more detailed study. Key words: Salinization, sulfates, sulfur isotopes, oxygen isotopes
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Dyachenko A. A., Blashenkov N. M., Berdnikov A. S., Gall L. N., Samsonova N. S., Semenov A. A., and Gall N. R. "Specialized mass spectrometer for determining the isotopic composition of lithium by ERIAD (electrospray with in source atomization)." Technical Physics Letters 48, no. 7 (2022): 1. http://dx.doi.org/10.21883/tpl.2022.07.54025.18919.
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A specialized isotope mass spectrometer for determining the isotopic ratio of lithium by ERIAD (electrospray with atomization in an ion source) is described. The device uses a Mattuha-Herzog-type mass analyzer with double focusing to use ion beams with a large spread in energy and simultaneous registration of signals of both lithium isotopes (6Li and 7Li), and a two-channel receiver based on a doublet of microchannel plates. The gas-dynamic interface is built according to the Kontorowitz-Gray scheme; from the gas-dynamic point of view, it is "long", that is, the distance between the nozzle and the skimmer is 4 times the size of the "Mach barrel" at the operating pressure (200 Pa). The device is desktop, its weight does not exceed 20 kg. The measurement time is 1000 s, sample replacement time is 100 s, measurement accuracy is ~ 0.1%. Keywords: mass spectrometry, electrospray, ion source, isotopes of lithium.
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Herbstritt, Barbara, Benjamin Gralher, and Markus Weiler. "Continuous, near-real-time observations of water stable isotope ratios during rainfall and throughfall events." Hydrology and Earth System Sciences 23, no. 7 (July 17, 2019): 3007–19. http://dx.doi.org/10.5194/hess-23-3007-2019.
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Abstract. The water isotopic composition of throughfall is affected by complex diffusive exchange with ambient water vapour, evaporative enrichment of heavy isotopes, and mixing processes in the tree canopy. All interception processes occur simultaneously in space and time, generating a complex pattern of throughfall depth and water isotopic composition. This pattern ultimately cascades through the entire hydrologic system and is therefore crucial for isotope studies in catchment hydrology, where recharge areas are often forested, while reference meteorological stations are generally in the open. For the quasi real-time observation of the water isotopic composition (δ18O and δ2H) of both gross precipitation and throughfall, we developed an approach combining a membrane contactor (Membrana) with a laser-based Cavity Ring-Down Spectrometer (CRDS, Picarro), obtaining isotope readings every 2 s. A setup with two CRDS instruments in parallel analysing gross precipitation and throughfall simultaneously was used for the continuous observation of the temporal effect of interception processes on the stable isotopes of water. All devices were kept small to minimize dead volume with time lags of only 4 min for water from the rainfall collectors to the isotope analysers to increase the temporal resolution of isotope observations. Complementarily, meteorological variables were recorded at high temporal resolution at the same location. The achieved evolution from discrete liquid or event-based bulk samples to continuous measurements allows for direct comparison of water stable isotope data with common meteorological measurements. Future improvements of the spatial representativeness will make our approach an even more powerful tool towards detailed insight into the dynamic processes contributing to interception during rainfall events.
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Lin, Mang, Xiaolin Zhang, Menghan Li, Yilun Xu, Zhisheng Zhang, Jun Tao, Binbin Su, Lanzhong Liu, Yanan Shen, and Mark H. Thiemens. "Five-S-isotope evidence of two distinct mass-independent sulfur isotope effects and implications for the modern and Archean atmospheres." Proceedings of the National Academy of Sciences 115, no. 34 (August 6, 2018): 8541–46. http://dx.doi.org/10.1073/pnas.1803420115.
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The signature of mass-independent fractionation of quadruple sulfur stable isotopes (S-MIF) in Archean rocks, ice cores, and Martian meteorites provides a unique probe of the oxygen and sulfur cycles in the terrestrial and Martian paleoatmospheres. Its mechanistic origin, however, contains some uncertainties. Even for the modern atmosphere, the primary mechanism responsible for the S-MIF observed in nearly all tropospheric sulfates has not been identified. Here we present high-sensitivity measurements of a fifth sulfur isotope, stratospherically produced radiosulfur, along with all four stable sulfur isotopes in the same sulfate aerosols and a suite of chemical species to define sources and mechanisms on a field observational basis. The five-sulfur-isotope and multiple chemical species analysis approach provides strong evidence that S-MIF signatures in tropospheric sulfates are concomitantly affected by two distinct processes: an altitude-dependent positive 33S anomaly, likely linked to stratospheric SO2 photolysis, and a negative 36S anomaly mainly associated with combustion. Our quadruple stable sulfur isotopic measurements in varying coal samples (formed in the Carboniferous, Permian, and Triassic periods) and in SO2 emitted from combustion display normal 33S and 36S, indicating that the observed negative 36S anomalies originate from a previously unknown S-MIF mechanism during combustion (likely recombination reactions) instead of coal itself. The basic chemical physics of S-MIF in both photolytic and thermal reactions and their interplay, which were not explored together in the past, may be another ingredient for providing deeper understanding of the evolution of Earth’s atmosphere and life’s origin.
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Kaiser, J., T. Röckmann, C. A. M. Brenninkmeijer, and P. J. Crutzen. "Wavelength dependence of isotope fractionation in N<sub>2</sub>O photolysis." Atmospheric Chemistry and Physics Discussions 2, no. 5 (October 28, 2002): 1735–63. http://dx.doi.org/10.5194/acpd-2-1735-2002.
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Abstract. In previous reports on isotopic fractionation in the ultraviolet photolysis of nitrous oxide (N2O) only enrichments of heavy isotopes in the remaining N2O fraction have been found. However, most direct photolysis experiments have been performed at wavelengths far from the absorption maximum at 182 nm. Here we present high-precision measurements of the 15N and 18O fractionation constants (e) in photolysis at 185 nm. Small, but statistically robust depletions of heavy isotopes for the terminal atoms in the linear N2O molecule are found. This means that the absorption cross sections s(15N14N16O) and s(14N218O) are larger than s(14N216O) at this specific wavelength. In contrast, the central N atom becomes enriched in 15N. The corresponding fractionation constants (±1 standard deviation) are 15e1 = s(15N14N16O)/s(14N216O) - 1 = (3.7 ± 0.2)%o 18e = s(14N218O)/s(14N216O) - 1 = (4.5 ± 0.2)%o and 15e2 = s(\\chem{14N15N16O)/s(14N216O) - 1 = (-18.6 ± 0.5) %o To our knowledge, this is the first documented case of such a heavy isotope depletion in the photolysis of N2O which supports theoretical models and pioneering vacuum ultraviolet spectroscopic measurements of 15N substituted N2O species that predict fluctuations of e around zero in this spectral region (Selwyn and Johnston, 1981). Such a variability in isotopic fractionation could have consequences for atmospheric models of N2O isotopes since actinic flux varies also strongly over narrow wavelength regions between 175 and 200 nm due to the Schumann-Runge bands of oxygen. However, the spacing between maxima and minima of the fractionation constants and of the actinic flux differ by two orders of magnitude in the wavelength domain. The wavelength dependence of fractionation constants in N2O photolysis can thus be approximated by a linear fit with negligible consequences on the actual value of the spectrally averaged fractionation constant. In order to establish this linear fit, additional measurements at wavelengths other than 185 nm were made using broadband light sources, namely D2, Hg/Xe and Sb lamps. The latter lamp was used in conjunction with various interference filters to shift the peak photolysis rate to longer wavelengths. From these experiments and existing data in the literature, a comprehensive picture of the wavelength dependence of N2O photolysis is created.
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Holzkämper, Steffen, Päivi Kaislahti Tillman, Peter Kuhry, and Jan Esper. "Comparison of stable carbon and oxygen isotopes in Picea glauca tree rings and Sphagnum fuscum moss remains from subarctic Canada." Quaternary Research 78, no. 2 (June 20, 2012): 295–302. http://dx.doi.org/10.1016/j.yqres.2012.05.014.
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AbstractStable isotope ratios from tree rings and peatland mosses have become important proxies of past climate variations. We here compare recent stable carbon and oxygen isotope ratios in cellulose of tree rings from white spruce (Picea glauca), growing near the arctic tree line; and cellulose of Sphagnum fuscum stems, growing in a hummock of a subarctic peatland, in west-central Canada. Results show that carbon isotopes in S. fuscum correlate significantly with July temperatures over the past ~20 yr. The oxygen isotopes correlate with both summer temperature and precipitation. Analyses of the tree-ring isotopes revealed summer temperatures to be the main controlling factor for carbon isotope variations, whereas tree-ring oxygen isotope ratios are controlled by a combination of spring temperatures and precipitation totals. We also explore the potential of combining high-frequency (annual) climate signals derived from long tree-ring series with low-frequency (decadal to centennial) climate signals derived from the moss remains in peat deposits. This cross-archive comparison revealed no association between the oxygen isotopes, which likely results from the varying sensitivity of the archives to different seasons. For the carbon isotopes, common variance could be achieved through adjustments of the Sphagnum age model within dating error.
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Farouqi, K., K. L. Kratz, and B. Pfeiffer. "Co-Production of Light p-, s- and r-Process Isotopes in the High-Entropy Wind of Type II Supernovae." Publications of the Astronomical Society of Australia 26, no. 3 (2009): 194–202. http://dx.doi.org/10.1071/as08075.
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AbstractWe have performed large-scale nucleosynthesis calculations within the high-entropy-wind (HEW) scenario of Type II supernovae. The primary aim was to constrain the conditions for the production of the classical ‘p-only’ isotopes of the light trans-Fe elements. We find, however, that for electron fractions in the range 0.458 ≤ Ye ≤ 0.478, sizeable abundances of p-, s- and r-process nuclei between 64Zn and 98Ru are coproduced in the HEW at low entropies (S ≤ 100) by a primary charged-particle process after an α-rich freezeout. With the above Ye–S correlation, most of the predicted isotopic abundance ratios within a given element, e.g. 64Zn(p)/70Zn(r) or 92Mo(p)/94Mo(p), as well as of neighboring elements, e.g. 70Ge(s + p)/74Se(p) or 74Se(p)/78Kr(p) agree with the observed Solar-System ratios. Taking the Mo isotopic chain as a particularly challenging example, we show that our HEW model can account for the production of all 7 stable isotopes, from ‘p-only’ 92Mo, via ‘s-only’ 96Mo up to ‘r-only’ 100Mo. Furthermore, our model is able to reproduce the isotopic composition of Mo in presolar SiC X-grains.
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Collet, R., M. Asplund, and P. E. Nissen. "The Barium Isotopic Abundance in the Metal-Poor Star HD140283." Publications of the Astronomical Society of Australia 26, no. 3 (2009): 330–34. http://dx.doi.org/10.1071/as08057.
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AbstractWe derive the mixture of odd to even barium isotopes in the atmosphere of the metal-poor subgiant HD140283 from the analysis of the Ba ii transition at 4554 Å in a high-resolution high signal-to-noise spectrum of the star. The detailed shape of this spectral line depends on the relative contributions of odd and even isotopes via isotopic and hyperfine splitting. We measure the fractional abundance of odd Ba isotopes by modelling the formation of the Ba ii 4554-Å line profile with the use of both a classical 1D hydrostatic and a 3D hydrodynamical model atmosphere of HD140283. We interpret the results in terms of contributions by the slow (s) and rapid (r) neutron-capture processes to the isotopic mix. While the result of the 1D analysis of the Ba ii feature indicates a 64 ± 36% contribution of the r-process to the isotopic mix, the 3D analysis points toward a mere 15 ± 34% contribution from this process, that is consistent with a solar-like mixture of barium isotopes.
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Thomassot, Emilie, Jonathan O’Neil, Don Francis, Pierre Cartigny, and Boswell A. Wing. "Atmospheric record in the Hadean Eon from multiple sulfur isotope measurements in Nuvvuagittuq Greenstone Belt (Nunavik, Quebec)." Proceedings of the National Academy of Sciences 112, no. 3 (January 5, 2015): 707–12. http://dx.doi.org/10.1073/pnas.1419681112.
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Mass-independent fractionation of sulfur isotopes (S-MIF) results from photochemical reactions involving short-wavelength UV light. The presence of these anomalies in Archean sediments [(4–2.5 billion years ago, (Ga)] implies that the early atmosphere was free of the appropriate UV absorbers, of which ozone is the most important in the modern atmosphere. Consequently, S-MIF is considered some of the strongest evidence for the lack of free atmospheric oxygen before 2.4 Ga. Although temporal variations in the S-MIF record are thought to depend on changes in the abundances of gas and aerosol species, our limited understanding of photochemical mechanisms complicates interpretation of the S-MIF record in terms of atmospheric composition. Multiple sulfur isotope compositions (δ33S, δ34S, and δ36S) of the >3.8 billion-year-old Nuvvuagittuq Greenstone Belt (Ungava peninsula) have been investigated to track the early origins of S-MIF. Anomalous S-isotope compositions (Δ33S up to +2.2‰) confirm a sedimentary origin of sulfide-bearing banded iron and silica-rich formations. Sharp isotopic transitions across sedimentary/igneous lithological boundaries indicate that primary surficial S-isotope compositions have been preserved despite a complicated metamorphic history. Furthermore, Nuvvuagittuq metasediments recorded coupled variations in 33S/32S, 34S/32S, and 36S/32S that are statistically indistinguishable from those identified several times later in the Archean. The recurrence of the same S-isotope pattern at both ends of the Archean Eon is unexpected, given the complex atmospheric, geological, and biological pathways involved in producing and preserving this fractionation. It implies that, within 0.8 billion years of Earth’s formation, a common mechanism for S-MIF production was established in the atmosphere.
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Sim, Min Sub, Shuhei Ono, and Tanja Bosak. "Effects of Iron and Nitrogen Limitation on Sulfur Isotope Fractionation during Microbial Sulfate Reduction." Applied and Environmental Microbiology 78, no. 23 (September 21, 2012): 8368–76. http://dx.doi.org/10.1128/aem.01842-12.
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ABSTRACTSulfate-reducing microbes utilize sulfate as an electron acceptor and produce sulfide that is depleted in heavy isotopes of sulfur relative to sulfate. Thus, the distribution of sulfur isotopes in sediments can trace microbial sulfate reduction (MSR), and it also has the potential to reflect the physiology of sulfate-reducing microbes. This study investigates the relationship between the availability of iron and reduced nitrogen and the magnitude of S-isotope fractionation during MSR by a marine sulfate-reducing bacterium, DMSS-1, aDesulfovibriospecies, isolated from salt marsh in Cape Cod, MA. Submicromolar levels of iron increase sulfur isotope fractionation by about 50% relative to iron-replete cultures of DMSS-1. Iron-limited cultures also exhibit decreased cytochromec-to-total protein ratios and cell-specific sulfate reduction rates (csSRR), implying changes in the electron transport chain that couples carbon and sulfur metabolisms. When DMSS-1 fixes nitrogen in ammonium-deficient medium, it also produces larger fractionation, but it occurs at faster csSRRs than in the ammonium-replete control cultures. The energy and reducing power required for nitrogen fixation may be responsible for the reverse trend between S-isotope fractionation and csSRR in this case. Iron deficiency and nitrogen fixation by sulfate-reducing microbes may lead to the large observed S-isotope effects in some euxinic basins and various anoxic sediments.
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Borisov, Vasily. "Scientific search under the pressure of high responsibility: development of the technology of electromagnetic isotope separation in the framework of the USSR Atomic project." Science Management: Theory And Practice 3, no. 1 (March 25, 2021): 120–35. http://dx.doi.org/10.19181/smtp.2021.3.1.7.
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One of the ways to obtain nuclear explosives for the manufacture of the first atomic bombs was the separation of uranium isotopes by electromagnetic (mass spectrographic) method. The theoretical justification and experimental separation of uranium isotopes by this method was carried out by L. A. Artsimovich in the Laboratory No. 2 of the USSR Academy of Sciences. By the middle of 1945, L. A. Artsimovich had obtained results at the experimental facility indicating the possibility of stable enrichment of uranium with the U-235 isotope using this method. Having the results of the experiments, the Design Bureau at the “Electrosila” plant (D. V. Efremov), with the participation of the Research Vacuum Institute (S. A. Vekshinsky) and the “A” Institute (M. Ardenne), developed a project of an industrial multi-chamber installation for electromagnetic separation of uranium isotopes SU-20. Such an installation was manufactured and put into operation at the newly created plant in the Urals, which allowed in 1951 to obtain the necessary amount of uranium-235 for the RDS-3 atomic bomb. After 1952, the technology of electromagnetic separation was no more used for the separation of uranium isotopes due to the improvement of more productive equipment for gas-diffusion separation of isotopes. The equipment of the electromagnetic isotope separation plant built in the Urals was used to produce lithium-6, needed to equip the first thermonuclear charge, which was successfully tested in 1953. In the next years, the electromagnetic isotope separation plant was involved in the manufacture of isotope products for scientific, technical and medical applications at wide range of utilization in Russia and abroad.
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Feland, Brett C., and Sylvie A. Quideau. "Isotope applications to soil science at the University of Alberta — an historical perspective." Canadian Journal of Soil Science 100, no. 4 (December 1, 2020): 344–55. http://dx.doi.org/10.1139/cjss-2019-0153.
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For the past 70 yr, researchers in the Soil Science/Renewable Resources Department at the University of Alberta have used isotopes to study topics of ecological importance. This review highlights the soil isotope research conducted within our department over this time, including an historical overview of studies of interest. Analytical techniques and advances in instrumentation are discussed, focusing on the measurement of light stable isotope ratios (i.e., for C, H, N, S, and O) using isotope ratio mass spectrometry (IRMS). Early soil isotope work (1950–2000s) focused on agricultural soils and soil fertility issues. These studies included the use of radioactive isotopes such as 14C and 35S, and (or) artificially enriched stable isotopes including 15N-labelled fertilizers. More recently (2000–present), the scope of research widened to include natural-abundance stable isotope ratio studies as higher-sensitivity IRMS systems became more prevalent. Current isotope research topics include N biogeochemistry in natural and managed ecosystems, land management effects on greenhouse gas emissions, carbon cycling in northern landscapes, paleo-reconstruction in peatlands, carbon sequestration in boreal forests, and biodegradation of petroleum hydrocarbons. Further technological progress also enabled new techniques such as compound-specific IRMS analysis, including δ13C and δ2H measurements of soil n-alkanes and phospholipid fatty acids. In conclusion, current IRMS instrumentation presents unparalleled opportunities for multidisciplinary research to track carbon, plant nutrients, and pollutants as they move through soils.
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Church, R. P., S. Cristallo, J. C. Lattanzio, R. J. Stancliffe, O. Straniero, and R. C. Cannon. "montage: AGB Nucleosynthesis with Full s-Process Calculations." Publications of the Astronomical Society of Australia 26, no. 3 (2009): 217–24. http://dx.doi.org/10.1071/as09008.
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AbstractWe present montage, a post-processing nucleosynthesis code that combines a traditional network for isotopes lighter than calcium with a rapid algorithm for calculating the s-process nucleosynthesis of the heavier isotopes. The separation of those parts of the network where only neutron-capture and beta-decay reactions are significant provides a substantial advantage in computational efficiency. We present the yields for a complete set of s-process isotopes for a 3-M⊙, Z = 0.02 stellar model, as a demonstration of the utility of the approach. Future work will include a large grid of models suitable for use in calculations of Galactic chemical evolution.
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Sanborn, P. T., R. P. Brockley, and B. Mayer. "Stable isotope tracing of fertilizer sulphur uptake by lodgepole pine: foliar responses." Canadian Journal of Forest Research 41, no. 3 (March 2011): 493–500. http://dx.doi.org/10.1139/x10-222.
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A plot-scale fertilizer sulphur (S) stable isotope tracer study was established in 2001 in the Sub-Boreal Spruce biogeoclimatic zone in central interior British Columbia where S deficiencies are common in lodgepole pine ( Pinus contorta var. latifolia Engelm. ex S. Wats.) stands. Treatments used operationally realistic applications of 300 kg N·ha–1 as urea and 100 kg S·ha–1 as either sulphate (SO4) or elemental S (S0). δ34S values of fertilizer S differed by >9‰ from pretreatment δ34S values of total S in foliage at the two study sites (5.2‰ and 8.2‰). These differences enabled quantification of fertilizer uptake using isotopic analysis of post-treatment foliar S. Addition of K2SO4 with δ34S of +17.5‰ increased foliar δ34S by 3.5‰ and 6.6‰ at the two sites, respectively, in the year after treatment, indicating fertilizer contributions >40% to foliar total S. For a S0 fertilizer application with a δ34S value of +19.3‰, foliar δ34S increases were smaller but steadily increased, resulting in an average tracer S uptake of ~20% over three years. These results confirmed the more rapid availability of S from SO4-based fertilizers and demonstrated the feasibility of field tracer experiments using stable S isotopes at natural abundance levels.
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Evans, JR, TD Sharkey, JA Berry, and GD Farquhar. "Carbon Isotope Discrimination measured Concurrently with Gas Exchange to Investigate CO2 Diffusion in Leaves of Higher Plants." Functional Plant Biology 13, no. 2 (1986): 281. http://dx.doi.org/10.1071/pp9860281.
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Conventional gas-exchange techniques that measure the stomatal conductance and rate of CO2 assimilation of leaves were combined with measurements of the carbon isotope composition of CO2 in air passing over a leaf. Isotopic discrimination during uptake was determined from the difference in the carbon isotope composition of air entering and leaving the leaf chamber. Isotopic discrimination measured over the short term correlated strongly with that determined from combusted leaf material. Environmental conditions were manipulated to alter the relative influences of stomatal conductance and carboxylation on the discrimination of carbon isotopes by intact leaves. With C3 plants, discrimination increased as the gradient in partial pressure of CO2 across the stomata decreased. For C4 plants there was little change in discrimination despite substantial changes in the diffusion gradient across the sto- mata. These results are consistent with, and provide the first direct experimental support for, theoretical equations describing discrimination during photosynthesis. Despite uncertainties about various processes affecting carbon isotope composition, the resistance to the transfer of CO2 from the intercellular airspaces to the sites of carboxylation in the mesophyll chloroplasts was estimated using this technique. For wheat the estimated resistance was 1.2-2.4 m2 s bar mol -1.
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Дьячков, А. Б., А. А. Горкунов, А. В. Лабозин, С. М. Миронов, Г. О. Цветков, В. Я. Панченко, and В. А. Фирсов. "Исследование схемы селективной фотоионизации -=SUP=-177-=/SUP=-Lu." Журнал технической физики 126, no. 2 (2019): 103. http://dx.doi.org/10.21883/os.2019.02.47189.212-18.
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AbstractThe hyperfine structure of transitions in the three-step scheme 5 d 6 s ^22 D _3/2–5 d 6 s 6 p ^4 F $$_{{5/2}}^{^\circ }$$ –5 d 6 s 7 s ^4 D _3/2– (53 375 cm^–1) $$_{{1/2}}^{^\circ }$$ of lutetium ionization is studied for ^175Lu, ^176Lu, and ^177Lu isotopes using the photoionization laser spectroscopy method. Values of the magnetic dipole ( A ) and electric quadrupole ( B ) interaction constants are determined, as well as the energies, the isotope shifts, and the radiative lifetimes for the 5 d 6 s 7 s ^4 D _3/2 and (53 375 cm^–1) $$_{{1/2}}^{^\circ }$$ levels.
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Mausolf, Edward J., Erik V. Johnstone, Natalia Mayordomo, David L. Williams, Eugene Yao Z. Guan, and Charles K. Gary. "Fusion-Based Neutron Generator Production of Tc-99m and Tc-101: A Prospective Avenue to Technetium Theranostics." Pharmaceuticals 14, no. 9 (August 29, 2021): 875. http://dx.doi.org/10.3390/ph14090875.
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Presented are the results of 99mTc and 101Tc production via neutron irradiation of natural isotopic molybdenum (Mo) with epithermal/resonance neutrons. Neutrons were produced using a deuterium-deuterium (D-D) neutron generator with an output of 2 × 1010 n/s. The separation of Tc from an irradiated source of bulk, low-specific activity (LSA) Mo on activated carbon (AC) was demonstrated. The yields of 99mTc and 101Tc, together with their potential use in medical single-photon emission computed tomography (SPECT) procedures, have been evaluated from the perspective of commercial production, with a patient dose consisting of 740 MBq (20 mCi) of 99mTc. The number of neutron generators to meet the annual 40,000,000 world-wide procedures is estimated for each imaging modality: 99mTc versus 101Tc, D-D versus deuterium-tritium (D-T) neutron generator system outputs, and whether or not natural molybdenum or enriched targets are used for production. The financial implications for neutron generator production of these isotopes is also presented. The use of 101Tc as a diagnostic, therapeutic, and/or theranostic isotope for use in medical applications is proposed and compared to known commercial nuclear diagnostic and therapeutic isotopes.
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Chela-Flores, Julian. "Testing S isotopes as biomarkers for Mars." International Journal of Astrobiology 18, no. 05 (September 28, 2018): 436–39. http://dx.doi.org/10.1017/s1473550418000393.
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AbstractWe suggest testing S isotopes as biomarkers for Mars. An analogous robust biosignature has recently been proposed for the forthcoming exploration of the icy surface of Europa, and in the long term for the exploration of the surfaces of other icy moons of the outer solar system. We discuss relevant instrumentation for testing the presence of life itself in some sites, whether extinct or extant in order to complement a set of other independent biosignatures. We pay special attention to the possible early emergence of sulphate-metabolizing microorganisms, as it happened on the early Earth. Fortunately, possible sites happen to be at likely landing sites for future missions ExoMars and Mars 2020, including Oxia Planum and Mawrth Vallis. We suggest how to make additional feasible use of the instruments that have already been approved for future missions. With these instruments, the proposed measurements can allow testing S isotopes on Mars, especially with the Mars Organic Molecule Analyzer.
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Thakur, Smriti, and Shashi K. Dhiman. "A study of shell structure in normal to exotic nuclides within relativistic Hartree–Bogoliubov approximation." Modern Physics Letters A 34, no. 02 (January 20, 2019): 1950014. http://dx.doi.org/10.1142/s0217732319500147.
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The purpose of this work is to study theoretically the shell structure of even–even isotopes in Si, S, Ar and Ca and isotones at neutron number N = 0, 28, 50 and 82. We employed Covariant Relativistic self-consistent mean field models analogous to Kohn–Sham density functional theory to construct the Nuclear Density Functionals from Lagrangian densities based on meson exchange and point coupling models. The pairing correlations of nucleons are considered by the relativistic Hartree–Bogoliubov functional based on quasi-particle operators of Bogoliubov transformations. The theoretical calculations of shell closure parameter [Formula: see text](N) and the differential variation of the two-neutron separation energy [Formula: see text](Z, N) provide recognizable signature of shell closure at N = 14 and 20 in case of Si, N = 14, 20 and 28 in S, Ar and Ca isotopes and are consistent with recent experimental investigations of new sub-shell gaps.
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Grocholski, B. "Isotopes isolated after impact." Science 352, no. 6287 (May 12, 2016): 783–85. http://dx.doi.org/10.1126/science.352.6287.783-s.
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MA, CHUN-WANG, HUI-LING WEI, and YU-QI LI. "THE SYSTEMATIC BEHAVIOR IN THE FRAGMENTS OF THE CALCIUM ISOTOPES PROJECTILE FRAGMENTATION." International Journal of Modern Physics E 19, no. 08n09 (September 2010): 1545–52. http://dx.doi.org/10.1142/s0218301310015941.
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We have calculated the cross sections of the fragments produced in the projectile fragmentation of the even 36–52 Ca isotopes using the statistical abrasion-ablation model. The isospin effect in the projectile fragmentation are studied by investigating the peak positions and the widths of the fragment isotopic cross section distributions. The peak positions of the fragments isotopic cross section distributions have good linear correlation to the Z of the fragments and the correlations are fitted using the linear function. The correlations between slopes b and the binding energies of the neutron ( S n) of the projectile nuclei, the differences between the binding energies of the neutron and proton( S n- S p) of the projectile nuclei and the neutron-skin thickness (δnp) are studied. It is found that b and δnp has a good linear correlation for the neutron-rich projectile nuclei.
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Harada, Hideo. "Bias Effects on g- and s-Factors in Westcott Convention." Applied Sciences 11, no. 14 (July 16, 2021): 6558. http://dx.doi.org/10.3390/app11146558.
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For accuracy improvement of neutron activation analysis and neutron capture cross sections, bias effects are investigated on g- and s-factors in the Westcott convention. As origins of biases, a joining function shape, neutron temperature, and sample temperature have been investigated. Biases are quantitatively deduced for two 1/v isotopes (197Au, 59Co) and six non-1/v isotopes (241Am, 151Eu, 103Rh, 115In, 177Hf, 226Ra). The s-factor calculated with a joining function deduced recently by a detailed Monte Carlo simulation is compared to s-factors calculated with traditional joining functions by Westcott. The results show the bias induced by the sample temperature is small, in the order of 0.1% for the g-factor and in the order of 1% for the s-factor. On the other hand, the bias size induced by a joining function shape for the s-factor depends significantly on both isotopes and neutron temperature. As a result, the reaction rates are also affected significantly. The bias size for the reaction rate is given in the case of an epithermal neutron index r = 0.1, for the eight isotopes.
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He, Yongfeng, Jinling Gong, Xingbing Wu, Yongjiu Zhu, and Deguo Yang. "Population Structure of Wild Schizothorax kozlovi in the Upper Yangtze River Based on mtDNA and Stable Isotopes, and Their Relationship with Ambient Temperature." Fishes 7, no. 5 (October 19, 2022): 292. http://dx.doi.org/10.3390/fishes7050292.
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Schizothorax kozlovi, as an endemic and vulnerable fish of the upper Yangtze River in China, faces many threats. In order to expose the population structure of wild S. kozlovi, the carbon and oxygen isotopic ratios in the otoliths, and the gene sequences of two common mitochondrial markers (Cytb and COI) were investigated in four sampling locations, and then their relationship with ambient temperature was further investigated. In general, it exhibits limited geographic population structuring of S. kozlovi in the upper Yangtze River by both mtDNA and stable isotopes. The values of otolith stable isotope ratios varied from −15.30‰ to −12.37‰ for δ18O and from −10.10‰ to −6.13‰ for δ13C. Significant relationships were revealed between stable isotope ratios and specific mean monthly water temperature variables (from November to March), indicating low temperature effect on otolith stable isotope ratios. Haplotype diversity and nucleotide diversity were 0.928 and 0.00778, both exhibiting high levels. A median-joining haplotype network indicated a mixture of geographical distribution but exhibited two distinct haplotype lineages (Clade I and Clade II). AMOVA detected that the higher percentage of genetic variance was within sampling locations (96.94%) and between two haplotype lineages (72.82%). Most FST values between sampling locations showed small levels of genetic differentiation except the differentiation between population SJ (Sanjiangkou) and JP (Jinping). Therefore, two haplotype lineages and population JP of S. kozlovi in the upper Yangtze River are suggested as three management units for conservation due to their moderate-to-great genetic differentiation and isolated habitat.
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MENG, XINGWEI, XIAOHU LI, FENGYOU CHU, BIN FU, JIJIANG LEI, ZHENGGANG LI, HAO WANG, and LIN CHEN. "Multi-stage growth and fluid evolution of a hydrothermal sulphide chimney in the East Pacific Ridge 1–2° S hydrothermal field: constraints from in situ sulphur isotopes." Geological Magazine 156, no. 06 (May 11, 2018): 989–1002. http://dx.doi.org/10.1017/s0016756818000316.
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AbstractSulphur isotopes can be used as a powerful tool to trace fluid evolution and explore the formation of chimneys. To clarify the in situ S isotopic variations of sulphides at the micro-scale, we analyzed a sulphide chimney collected from the hydrothermal field in the East Pacific Rise 1–2° S using a sensitive high-mass-resolution ion micro-probe for stable isotopes (SHRIMP SI). Three mineral zones can be identified in the chimney: an external outer wall of porous anhydrite and colloform pyrite, an internal middle zone of sub-euhedral pyrite and massive chalcopyrite, and an inner zone of massive pyrite. The δ34SV-CDT values of the sulphides fall within the range 1.83–7.51 ‰ (avg. 4.05 ‰, n = 16), and S isotopic values increase from the core (3.09 ‰, n = 3) to the middle (3.78 ‰, n = 11) to the edge (6.99 ‰, n = 2). These results illustrate mineral crystallization processes and the mixing between seawater-derived S and magmatic–hydrothermal fluids during the growth of the chimney. The zones from the edge to the core are characterized by crystal morphologies of colloform/anhedral pyrite to massive pyrite with decreasing δ34S values, revealing multi-stage mineral deposition and sulphur isotopic fractionation. In contrast to the increase in δ34S values from the core to the edge in one profile (profile A), anomalously low δ34S values in fine-grained pyrite relative to chalcopyrite in another profile (profile B) in the middle zone result from S isotopic exchange between seawater SO42− and fluid H2S due to different fluid–seawater mixing, possibly caused by variations in permeability and porosity across the chimney.
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Akers, Pete D., Ben G. Kopec, Kyle S. Mattingly, Eric S. Klein, Douglas Causey, and Jeffrey M. Welker. "Baffin Bay sea ice extent and synoptic moisture transport drive water vapor isotope (<i>δ</i><sup>18</sup>O, <i>δ</i><sup>2</sup>H, and deuterium excess) variability in coastal northwest Greenland." Atmospheric Chemistry and Physics 20, no. 22 (November 19, 2020): 13929–55. http://dx.doi.org/10.5194/acp-20-13929-2020.
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Abstract. At Thule Air Base on the coast of Baffin Bay (76.51∘ N, 68.74∘ W), we continuously measured water vapor isotopes (δ18O, δ2H) at a high frequency (1 s−1) from August 2017 through August 2019. Our resulting record, including derived deuterium excess (dxs) values, allows an analysis of isotopic–meteorological relationships at an unprecedented level of detail and duration for high Arctic Greenland. We examine isotopic variability across multiple temporal scales from daily to interannual, revealing that isotopic values at Thule are predominantly controlled by the sea ice extent in northern Baffin Bay and the synoptic flow pattern. This relationship can be identified through its expression in the following five interacting factors: (a) local air temperature, (b) local marine moisture availability, (c) the North Atlantic Oscillation (NAO), (d) surface wind regime, and (e) land-based evaporation and sublimation. Each factor's relative importance changes based on the temporal scale and in response to seasonal shifts in Thule's environment. Winter sea ice coverage forces distant sourcing of vapor that is isotopically light from fractionation during transport, while preventing isotopic exchange with local waters. Sea ice breakup in late spring triggers a rapid isotopic change at Thule as the newly open ocean supplies warmth and moisture that has ∼10 ‰ and ∼70 ‰ higher δ18O and δ2H values, respectively, and ∼10 ‰ lower dxs values. Sea ice retreat also leads to other environmental changes, such as sea breeze development, that radically alter the nature of relationships between isotopes and many meteorological variables in summer. On synoptic timescales, enhanced southerly flow promoted by negative NAO conditions produces higher δ18O and δ2H values and lower dxs values. Diel isotopic cycles are generally very small as a result of a moderated coastal climate and the counteracting isotopic effects of the sea breeze, local evaporation, and convection. Future losses in Baffin Bay's sea ice extent will likely shift mean annual isotopic compositions toward more summer-like values, and local glacial ice could potentially preserve isotopic evidence of past reductions. These findings highlight the influence that the local environment can have on isotope dynamics and the need for dedicated, multiseason monitoring to fully understand the controls on water vapor isotope variability.
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Won, Eun-Ji, Seung Hee Kim, Young-Shin Go, K. Suresh Kumar, Min-Seob Kim, Suk-Hee Yoon, Germain Bayon, Jung-Hyun Kim, and Kyung-Hoon Shin. "A Multi-Elements Isotope Approach to Assess the Geographic Provenance of Manila Clams (Ruditapes philippinarum) via Recombining Appropriate Elements." Foods 10, no. 3 (March 18, 2021): 646. http://dx.doi.org/10.3390/foods10030646.
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The increasing global consumption of seafood has led to increased trade among nations, accompanied by mislabeling and fraudulent practices that have rendered authentication crucial. The multi-isotope ratio analysis is considered as applicable tool for evaluating geographical authentications but requires information and experience to select target elements such as isotopes, through a distinction method based on differences in habitat and physiology due to origin. The present study examined recombination conditions of multi-elements that facilitated geographically distinct classifications of the clams to sort out appropriate elements. Briefly, linear discriminant analysis (LDA) analysis was performed according to several combinations of five stable isotopes (carbon (δ13C), nitrogen (δ15N), oxygen (δ18O), hydrogen (δD), and sulfur (δ34S)) and two radiogenic elements (strontium (87Sr/86Sr) and neodymium (143Nd/144Nd)), and the geographical classification results of the Manila clam Ruditapes philippinarum from Democratic People’s Republic of Korea (DPR Korea), Korea and China were compared. In conclusion, linear discriminant analysis (LDA) with at least four elements (C, N, O, and S) including S revealed a remarkable cluster distribution of the clams. These findings expanded the application of systematic multi-elements analyses, including stable and radiogenic isotopes, to trace the origins of R. philippinarum collected from the Korea, China, and DPR Korea.
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Delavault, Hélène, Catherine Chauvel, Emilie Thomassot, Colin W. Devey, and Baptiste Dazas. "Sulfur and lead isotopic evidence of relic Archean sediments in the Pitcairn mantle plume." Proceedings of the National Academy of Sciences 113, no. 46 (October 24, 2016): 12952–56. http://dx.doi.org/10.1073/pnas.1523805113.
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The isotopic diversity of oceanic island basalts (OIB) is usually attributed to the influence, in their sources, of ancient material recycled into the mantle, although the nature, age, and quantities of this material remain controversial. The unradiogenic Pb isotope signature of the enriched mantle I (EM I) source of basalts from, for example, Pitcairn or Walvis Ridge has been variously attributed to recycled pelagic sediments, lower continental crust, or recycled subcontinental lithosphere. Our study helps resolve this debate by showing that Pitcairn lavas contain sulfides whose sulfur isotopic compositions are affected by mass-independent fractionation (S-MIF down to Δ33S = −0.8), something which is thought to have occurred on Earth only before 2.45 Ga, constraining the youngest possible age of the EM I source component. With this independent age constraint and a Monte Carlo refinement modeling of lead isotopes, we place the likely Pitcairn source age at 2.5 Ga to 2.6 Ga. The Pb, Sr, Nd, and Hf isotopic mixing arrays show that the Archean EM I material was poor in trace elements, resembling Archean sediment. After subduction, this Archean sediment apparently remained stored in the deep Earth for billions of years before returning to the surface as Pitcairn´s characteristic EM I signature. The presence of negative S-MIF in the deep mantle may also help resolve the problem of an apparent deficit of negative Δ33S anomalies so far found in surface reservoirs.
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Valle, Sonia R., and Sharon Z. Herzka. "Natural variability in δ18O values of otoliths of young Pacific sardine captured in Mexican waters indicates subpopulation mixing within the first year of life." ICES Journal of Marine Science 65, no. 2 (February 5, 2008): 174–90. http://dx.doi.org/10.1093/icesjms/fsn001.
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Abstract Valle, S. R., and Herzka, S. Z. 2008. Natural variability in δ18O values of otoliths of young Pacific sardine captured in Mexican waters indicates subpopulation mixing within the first year of life. – ICES Journal of Marine Science, 65: 174–190. Oxygen stable isotopes were measured in whole sagittae of young Pacific sardine (δ18Ooto) collected throughout their range in the Mexican Pacific to quantify natural variability, to reconstruct temperature histories, and to infer whether fish mix at a population or subpopulation level. Isotopic values and derived temperature estimates (Toto) of sardine captured simultaneously showed high variability (up to 2.0‰ and 10°C at a given location). Given limited variations in salinity, this implies differences in thermal history and the prevalence of subpopulation-level mixing processes. We tested the null hypothesis of local residence by comparing δ18Ooto values with predicted isotopic values on a location-specific basis, and age- and location-specific average sea surface temperatures (SSTs) with derived Toto. Some fish exhibited values outside the local range of predicted oxygen isotope values and SSTs, suggesting that they were not permanent residents. Using an otolith growth model, we show that otolith growth and age differences cannot fully account for the variability in δ18Ooto values. The absence of significant differences in δ18Ooto values between the Pacific and Gulf indicates that oxygen isotope ratios cannot be used to examine population structure or migration among these regions. However, they can be used to infer mixing within and among subpopulations.
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Dittmann, Anna, Elisabeth Schlosser, Valérie Masson-Delmotte, Jordan G. Powers, Kevin W. Manning, Martin Werner, and Koji Fujita. "Precipitation regime and stable isotopes at Dome Fuji, East Antarctica." Atmospheric Chemistry and Physics 16, no. 11 (June 6, 2016): 6883–900. http://dx.doi.org/10.5194/acp-16-6883-2016.
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Abstract. A unique set of 1-year precipitation and stable water isotope measurements from the Japanese Antarctic station, Dome Fuji, has been used to study the impact of the synoptic situation and the precipitation origin on the isotopic composition of precipitation on the Antarctic Plateau. The Antarctic Mesoscale Prediction System (AMPS) archive data are used to analyse the synoptic situations that cause precipitation. These situations are investigated and divided into five categories. The most common weather situation during a precipitation event is an upper-level ridge that extends onto the Antarctic Plateau and causes strong northerly advection from the ocean. Most precipitation events are associated with an increase in temperature and wind speed, and a local maximum of δ18O. During the measurement period, 21 synoptically caused precipitation events caused 60 % of the total annual precipitation, whereas the remaining 40 % were predominantly attributed to diamond dust. By combining the synoptic analyses with 5-day back-trajectories, the moisture source regions for precipitation events were estimated. An average source region around a latitude of 55° S was found. The atmospheric conditions in the source region were used as initial conditions for running a Rayleigh-type isotopic model in order to reproduce the measured isotopic composition of fresh snow and to investigate the influence of the precipitation source region on the isotope ratios. The model represents the measured annual cycle of δ18O and the second-order isotopic parameter deuterium excess reasonably well, but yields on average too little fractionation along the transport/cooling path. While simulations with an isotopic general circulation model (GCM) (ECHAM5-wiso) for Dome Fuji are on average closer to the observations, this model cannot reproduce the annual cycle of deuterium excess. In the event-based analysis, no evidence of a correlation of the measured deuterium excess with the latitude of the moisture source region or the corresponding conditions was identified. Contrary to the assumption used for decades in ice core studies, a more northerly moisture source does not necessarily mean a larger temperature difference between source area and deposition site, thus a more depleted precipitation in heavy isotopes with a higher deuterium excess.
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Warke, Matthew R., Tommaso Di Rocco, Aubrey L. Zerkle, Aivo Lepland, Anthony R. Prave, Adam P. Martin, Yuichiro Ueno, Daniel J. Condon, and Mark W. Claire. "The Great Oxidation Event preceded a Paleoproterozoic “snowball Earth”." Proceedings of the National Academy of Sciences 117, no. 24 (June 1, 2020): 13314–20. http://dx.doi.org/10.1073/pnas.2003090117.
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The inability to resolve the exact temporal relationship between two pivotal events in Earth history, the Paleoproterozoic Great Oxidation Event (GOE) and the first “snowball Earth” global glaciation, has precluded assessing causality between changing atmospheric composition and ancient climate change. Here we present temporally resolved quadruple sulfur isotope measurements (δ34S, ∆33S, and ∆36S) from the Paleoproterozoic Seidorechka and Polisarka Sedimentary Formations on the Fennoscandian Shield, northwest Russia, that address this issue. Sulfides in the former preserve evidence of mass-independent fractionation of sulfur isotopes (S-MIF) falling within uncertainty of the Archean reference array with a ∆36S/∆33S slope of −1.8 and have small negative ∆33S values, whereas in the latter mass-dependent fractionation of sulfur isotopes (S-MDF) is evident, with a ∆36S/∆33S slope of −8.8. These trends, combined with geochronological constraints, place the S-MIF/S-MDF transition, the key indicator of the GOE, between 2,501.5 ± 1.7 Ma and 2,434 ± 6.6 Ma. These are the tightest temporal and stratigraphic constraints yet for the S-MIF/S-MDF transition and show that its timing in Fennoscandia is consistent with the S-MIF/S-MDF transition in North America and South Africa. Further, the glacigenic part of the Polisarka Formation occurs 60 m above the sedimentary succession containing S-MDF signals. Hence, our findings confirm unambiguously that the S-MIF/S-MDF transition preceded the Paleoproterozoic snowball Earth. Resolution of this temporal relationship constrains cause-and-effect drivers of Earth’s oxygenation, specifically ruling out conceptual models in which global glaciation precedes or causes the evolution of oxygenic photosynthesis.
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Eriksen, J. "Measuring natural abundance of stable s isotopes in soil by isotope ratio mass spectrometry." Communications in Soil Science and Plant Analysis 27, no. 5-8 (March 1996): 1251–64. http://dx.doi.org/10.1080/00103629609369630.
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Kumar, Pankaj, and Shashi K. Dhiman. "Microscopic study of nuclear structure dynamics of neutron-deficient even–even 100–110Cd isotopes within the framework of projected shell model." Modern Physics Letters A 35, no. 23 (June 3, 2020): 2050189. http://dx.doi.org/10.1142/s0217732320501898.
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We have studied the deformation systematics of [Formula: see text] and [Formula: see text] values, yrast spectra, band structure and backbending phenomena in the neutron-deficient even–even [Formula: see text]Cd isotopes within the projected shell model (PSM) framework. The observations of the systematics of [Formula: see text] and [Formula: see text] values for [Formula: see text]Cd isotopes are well reproduced in present calculations. Our observations show that, as we move from [Formula: see text]Cd to [Formula: see text]Cd, the deformation increases and then it reduces up to [Formula: see text]Cd. This gives us a confirmation that [Formula: see text]Cd is the most deformed nucleus in this set of isotopic mass chain. The backbending phenomena is also observed in these isotopes, which can be related to the crossing of ground band (g-band) by 2-quasiparticle (qp) bands or s-bands. The pseudomagic character of [Formula: see text]Cd has also been observed.
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Akram, Waheed, Khalil Farouqi, Oliver Hallmann, and Karl-Ludwig Kratz. "Nucleosynthesis of light trans-Fe isotopes in ccSNe: Implications from presolar SiC-X grains." EPJ Web of Conferences 227 (2020): 01009. http://dx.doi.org/10.1051/epjconf/202022701009.
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This contribution presents an extension of our r-process parameter study within the high-entropy-wind (HEW) scenario of corecollapse supernovae (ccSNe). One of the primary aims of this study was to obtain indications for the production of classical p-, s- and r-isotopes of the light trans-Fe elements in the Solar System (S.S.). Here, we focus on the nucleosynthesis origin of the anomalous isotopic compositions of Zr, Mo and Ru in presolar SiC X-grains (SNe grains). In contrast to the interpretation of other groups, we show that these grains do not represent the signatures of a ‘clean’ stellar scenario, but rather, are mixtures of an exotic nucleosynthesis component and S.S. material. We further confirm the results of our earlier studies whereby sizeable amounts of all stable p-, s- and r-isotopes of Zr, Mo and Ru can be co-produced by moderately neutron-rich ejecta of the low-entropy, charged-particle scenario of ccSNe (type II). The synthesis of these isotopes through a ‘primary’ production mode provides further means to revise the abundance estimates of the light trans-Fe elements from so far favoured ‘secondary’ scenarios like Type Ia SNe or neutron-bursts in exploding massive stars.
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Benson, E. K., E. M. Ripley, C. Li, B. W. Underwood, and R. Mahin. "Multiple S Isotopes and S Isotope Heterogeneity at the East Eagle Ni-Cu-Platinum Group Element Deposit, Northern Michigan." Economic Geology 115, no. 3 (May 1, 2020): 527–41. http://dx.doi.org/10.5382/econgeo.4707.
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Abstract The East Eagle Ni-Cu-platinum group element deposit is a conduit-type deposit located in northern Michigan, in close spatial proximity to the currently producing Eagle deposit. Massive and semimassive (net-textured) sulfide mineralization at East Eagle occurs approximately 800 m lower in the stratigraphic sequence than that at Eagle and only ~200 m above the contact between Proterozoic and Archean rocks. Although sulfide mineralogy and textural types are similar at the two occurrences, there are important differences in their S isotope systematics. Massive sulfide mineralization at East Eagle is characterized by a relatively narrow range of δ34S values from 1.5 to 3.2‰. Semimassive sulfides show a similar range from 2.1 to 3.8‰. In strong contrast to these values, those from disseminated sulfides that border the massive and semimassive mineralization define a much larger range from –4.3 to 22.8‰. The much more restricted range in δ34S values recorded in the massive and semimassive sulfide mineralization compared to that of the disseminated mineralization is thought to reflect isotopic exchange reactions in the conduit involving accumulated sulfide and pulses of magma containing S of mantle origin. The ∆33S values of all three major types of sulfide mineralization at East Eagle are near 0‰, with most values between –0.03 and 0.03‰. Unlike ∆33S values from semimassive sulfide mineralization at Eagle, the ∆33S values at East Eagle show no, or very limited, evidence for the involvement of S derived from Archean sedimentary rocks. The wide range in δ34S values recorded in the disseminated mineralization provides strong evidence that S from Proterozoic sedimentary host rocks was involved in the mineralization; in some cases, as much as 85% of the S may have been of external origin. In addition to the wide range in δ34S values, the disseminated mineralization is characterized by spatially heterogeneous δ34S values. Meter-scale S isotope variations, as well as variations in Pt and Pd tenor, are consistent with multiple inputs of magma, each characterized by distinct S isotope ratios. Heterogeneity of several per mill at the centimeter scale indicates that the degree of supercooling exceeded the S diffusivity, preserving small-scale S isotope variability inherited from the sedimentary country-rock source. Elongate, branching plagioclase grains in many of the gabbroic rocks that host the disseminated sulfide mineralization are consistent with a rapid second stage of cooling.
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Tsirogiannis, George, Anna-Akrivi Thomatou, Eleni Psarra, Eleni C. Mazarakioti, Katerina Katerinopoulou, Anastasios Zotos, Achilleas Kontogeorgos, Angelos Patakas, and Athanasios Ladavos. "Probabilistic Machine Learning for the Authentication of the Protected Designation of Origin of Greek Bottarga from Messolongi: A Generic Methodology to Cope with Very Small Number of Samples." Applied Sciences 12, no. 13 (June 22, 2022): 6335. http://dx.doi.org/10.3390/app12136335.
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Consumers are increasingly interested in the geographical origin of foodstuff, as an important characteristic of food authenticity and quality. To assure the authenticity of the geographical origin, various methods have been proposed. Stable isotope analysis is a method that has been extensively used for products like wine, oil, and meat by using large datasets and analysis. On the other hand, only few studies have been conducted for the discrimination of seafood origin and especially for mullet roes or bottarga products, and even fewer investigate a small number of samples and datasets. Stable isotopes of Carbon (C), Nitrogen (N), and Sulfur (S) analysis of bottarga samples from four different origins were carried out. The first results show that the stable isotopes ratios of C, N, and S could be used to discriminate the Greek PDO Bottarga (Messolongi) from other similar products by using a probabilistic machine learning methodology. That could use limited sample data to fit/estimate their parameters, while, at the same time, being capable of describing accurately the population and discriminate individual samples regarding their origin.
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Doi, Hideyuki, Yasuhiro Takemon, Taichi Ohta, Yuko Ishida, and Eisuke Kikuchi. "Effects of reach-scale canopy cover on trophic pathways of caddisfly larvae in a Japanese mountain stream." Marine and Freshwater Research 58, no. 9 (2007): 811. http://dx.doi.org/10.1071/mf07067.
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Differences in trophic pathways between reaches with and without tree canopy cover above the channel were assessed using stable isotopes in a 1.4-km stretch of the Kamo River, Japan. The trophic pathways of two larval trichopteran species, a grazer (Goera joponica, Goeridae) inhabiting stone surfaces and a net-spinning filter-feeder (Stenopsyche marmorata, Stenopsychidae) inhabiting interstices of the stony stream bottom, were estimated using carbon and nitrogen isotopes in reaches with and without canopy cover in winter. The δ13C values of G. japonica were similar to those of periphyton at each station, suggesting that G. japonica is a grazer on periphyton. A significant positive correlation between carbon isotope values of S. marmorata and benthic particulate organic matter (BPOM) indicated that BPOM varied in composition according to the amount of solar energy within a reach. In addition, there was a significant positive correlation between carbon isotope values of filter-feeders and the periphytic algal contribution to BPOM using an isotope mixing model, indicating that the main food source of the filter feeders was derived from the in situ periphytic algae in open reaches and from a terrestrial source in canopy-covered reaches.
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Saitoh, Masafumi, Sami Nabhan, Christophe Thomazo, Nicolas Olivier, Jean-François Moyen, Yuichiro Ueno, and Johanna Marin-Carbonne. "Multiple Sulfur Isotope Records of the 3.22 Ga Moodies Group, Barberton Greenstone Belt." Geosciences 10, no. 4 (April 16, 2020): 145. http://dx.doi.org/10.3390/geosciences10040145.
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The Moodies Group, the uppermost unit in the Barberton Greenstone Belt (BGB) in South Africa, is a ~3.7-km-thick coarse clastic succession accumulated on terrestrial-to-shallow marine settings at around 3.22 Ga. The multiple sulfur isotopic composition of pyrite of Moodies intervals was newly obtained to examine the influence of these depositional settings on the sulfur isotope record. Conglomerate and sandstone rocks were collected from three synclines north of the Inyoka Fault of the central BGB, namely, the Eureka, Dycedale, and Saddleback synclines. The sulfur isotopic composition of pyrite was analyzed by Secondary Ion Mass Spectrometry (SIMS) for 6 samples from the three synclines and by Isotope Ratio Mass Spectrometry (IR-MS) for 17 samples from a stratigraphic section in the Saddleback Syncline. The present results show a signal of mass-independent fractionation of sulfur isotopes (S-MIF), although t-tests statistically demonstrated that the Moodies S-MIF signals (mostly 0‰ < ∆33S < +0.5‰) are significantly small compared to the signal of the older Paleoarchean (3.6–3.2 Ga) records. These peculiar signatures might be related to initial deposition of detrital pyrite of juvenile origin from the surrounding intrusive (tonalite–trondhjemite–granodiorite; TTG) and felsic volcanic rocks, and/or to secondary addition of hydrothermal sulfur during late metasomatism. Moreover, fast accumulation (~0.1–1 mm/year) of the Moodies sediments might have led to a reduced accumulation of sulfur derived from an atmospheric source during their deposition. As a result, the sulfur isotopic composition of the sediments may have become susceptible to the secondary addition of metasomatic sulfur on a mass balance point of view. The sulfur isotopic composition of Moodies pyrite is similar to the composition of sulfides from nearby gold mines. It suggests that, after the Moodies deposition, metasomatic pyrite formation commonly occurred north of the Inyoka Fault in the central BGB at 3.1–3.0 Ga.
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Kämpf, Lucas, Birgit Plessen, Stefan Lauterbach, Carla Nantke, Hanno Meyer, Bernhard Chapligin, and Achim Brauer. "Stable oxygen and carbon isotopes of carbonates in lake sediments as a paleoflood proxy." Geology 48, no. 1 (October 16, 2019): 3–7. http://dx.doi.org/10.1130/g46593.1.
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Abstract Lake sediments are increasingly explored as reliable paleoflood archives. In addition to established flood proxies including detrital layer thickness, chemical composition, and grain size, we explore stable oxygen and carbon isotope data as paleoflood proxies for lakes in catchments with carbonate bedrock geology. In a case study from Lake Mondsee (Austria), we integrate high-resolution sediment trapping at a proximal and a distal location and stable isotope analyses of varved lake sediments to investigate flood-triggered detrital sediment flux. First, we demonstrate a relation between runoff, detrital sediment flux, and isotope values in the sediment trap record covering the period 2011–2013 CE including 22 events with daily (hourly) peak runoff ranging from 10 (24) m3 s−1 to 79 (110) m3 s−1. The three- to ten-fold lower flood-triggered detrital sediment deposition in the distal trap is well reflected by attenuated peaks in the stable isotope values of trapped sediments. Next, we show that all nine flood-triggered detrital layers deposited in a sediment record from 1988 to 2013 have elevated isotope values compared with endogenic calcite. In addition, even two runoff events that did not cause the deposition of visible detrital layers are distinguished by higher isotope values. Empirical thresholds in the isotope data allow estimation of magnitudes of the majority of floods, although in some cases flood magnitudes are overestimated because local effects can result in too-high isotope values. Hence we present a proof of concept for stable isotopes as reliable tool for reconstructing flood frequency and, although with some limitations, even for flood magnitudes.
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Brown, B. Alex. "The oxygen isotopes." International Journal of Modern Physics E 26, no. 01n02 (January 2017): 1740003. http://dx.doi.org/10.1142/s0218301317400031.
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The properties of the oxygen isotopes provide diverse examples of progress made in experiments and theory. This chain of isotopes has been studied from beyond the proton drip line in [Formula: see text]O to beyond the neutron drip line in [Formula: see text]O. This short survey starts with the microscopic G matrix approach for [Formula: see text]O of Kuo and Brown in the 1960’s and shows how theory has evolved. The nuclear structure around the doubly-magic nucleus [Formula: see text]O is particularly simple in terms of the nuclear shell model. The nuclear structure around the doubly-magic nucleus [Formula: see text]O exhibits the coexistence of single-particle and collective structure.
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Iben, Icko. "Asymptotic Giant Branch Stars: Thermal Pulses, Carbon Production, and Dredge Up; Neutron Sources and s-Process Nucleosynthesis." Symposium - International Astronomical Union 145 (1991): 257–74. http://dx.doi.org/10.1017/s0074180900227423.
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A brief review is given of the structure of asymptotic giant branch (AGB) stars and of the characteristics of the thermal pulses which these stars experience. Following a pulse, model AGB stars with a large core mass easily dredge up fresh carbon, which is the main product of incomplete helium burning, and s-process isotopes, which are made as a consequence of the activation of the 22Ne neutron source. Model AGB stars of small core mass activate the 13C neutron source and produce s-process isotopes in nearly the solar system distribution. They also dredge up fresh carbon and s-process isotopes, but only if overshoot or some other form of “extra” mixing beyond the lower boundary of the convective envelope is invoked.
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Zhou, Xun. "Some Series and Mathematic Constants Arising in Radioactive Decay." Journal of Mathematics Research 11, no. 6 (October 28, 2019): 14. http://dx.doi.org/10.5539/jmr.v11n6p14.
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In this paper we show the construction of 32 infinite series based on the law of decay of radioactive isotopes, which indicates that a radioactive parent isotope is reduced by 1/2 and 1/e of its initial value during each half-life and mean life, respectively. We found that the ratios among the values of the radioactive parent isotope and the radiogenic daughter isotope for each half-life’s and mean life’s decay can be used to construct 16 half-life related (or 2-related) and 16 mean life related (or e-related) infinite series. There are 8 divergent series, 4 previously known convergent series and 2 series converging to the Erdös-Borwein constant. The remaining 18 series are found to converge to 18 mathematical constants and the divergent and alternating mean life related series leads to another 2 mathematical constants. A few interesting mathematical relations exist among these convergent series and 5 sequences are also attained from the convergent half-life related series.
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VICKRIDGE, I. C. "APPLICATIONS OF ION BEAM ANALYSIS TO THE ELEMENTAL AND ISOTOPIC CHARACTERISATION OF ADVANCED MATERIALS." Modern Physics Letters B 15, no. 28n29 (December 20, 2001): 1271–80. http://dx.doi.org/10.1142/s0217984901003160.
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The accelerator laboratory of the Groupe de Physique des Solides, Paris, has pioneered a number of IBA techniques and applications over the last few decades. In particular, in the 1960's and 1970's, Nuclear Reaction analysis (NRA) including nuclear resonance depth profiling, isotopic tracing combined with NRA, and channelling techniques were developed under the leadership of G. Amsel. In this paper I will present a selection of recent applications from this laboratory of NRA, isotopic tracing with stable isotopes, and ion channelling, intended to illustrate the present status of these techniques in condensed matter physics and materials science, and to act as a backdrop for a discussion of future directions for development of Ion Beam Analysis in condensed matter physics and advanced materials research.
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Humire, P. K., V. Thiel, C. Henkel, A. Belloche, J. C. Loison, T. Pillai, D. Riquelme, et al. "Sulphur and carbon isotopes towards Galactic centre clouds." Astronomy & Astrophysics 642 (October 2020): A222. http://dx.doi.org/10.1051/0004-6361/202038216.
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Context. Measuring isotopic ratios is a sensitive technique used to obtain information on stellar nucleosynthesis and chemical evolution. Aims. We present measurements of the carbon and sulphur abundances in the interstellar medium of the central region of our Galaxy. The selected targets are the +50 km s−1 Cloud and several line-of-sight clouds towards Sgr B2(N). Methods. Towards the +50 km s−1 Cloud, we observed the J = 2–1 rotational transitions of 12C32S, 12C34S, 13C32S, 12C33S, and 13C34S, and the J = 3–2 transitions of 12C32S and 12C34S with the IRAM-30 m telescope, as well as the J = 6–5 transitions of 12C34S and 13C32S with the APEX 12 m telescope, all in emission. The J = 2–1 rotational transitions of 12C32S, 12C34S, 13C32S, and 13C34S were observed with ALMA in the envelope of Sgr B2(N), with those of 12C32S and 12C34S also observed in the line-of-sight clouds towards Sgr B2(N), all in absorption. Results. In the +50 km s−1 Cloud we derive a 12C/13C isotopic ratio of 22.1−2.4+3.3, that leads, with the measured 13C32S/12C34S line intensity ratio, to a 32S/34S ratio of 16.3−2.4+3.0. We also derive the 32S/34S isotopic ratio more directly from the two isotopologues 13C32S and 13C34S, which leads to an independent 32S/34S estimation of 16.3−1.7+2.1 and 17.9 ± 5.0 for the +50 km s−1 Cloud and Sgr B2(N), respectively. We also obtain a 34S/33S ratio of 4.3 ± 0.2 in the +50 km s−1 Cloud. Conclusions. Previous studies observed a decreasing trend in the 32S/34S isotopic ratios when approaching the Galactic centre. Our result indicates a termination of this tendency at least at a galactocentric distance of 130−30+60 pc. This is at variance with findings based on 12C/13C, 14N/15N, and 18O/17O isotope ratios, where the above-mentioned trend is observed to continue right to the central molecular zone. This can indicate a drop in the production of massive stars at the Galactic centre, in the same line as recent metallicity gradient ([Fe/H]) studies, and opens the work towards a comparison with Galactic and stellar evolution models.
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Neuholz, René, Charlotte Kleint, Bernhard Schnetger, Andrea Koschinsky, Patrick Laan, Rob Middag, Sylvia Sander, et al. "Submarine Hydrothermal Discharge and Fluxes of Dissolved Fe and Mn, and He Isotopes at Brothers Volcano Based on Radium Isotopes." Minerals 10, no. 11 (October 29, 2020): 969. http://dx.doi.org/10.3390/min10110969.
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Hydrothermal venting is an important transfer process of energy and elements between the Earth’s solid material and the oceans. Compared to mid-ocean-ridge hydrothermal vent fields, those at intra-oceanic island arcs are typically in shallower water depth and have a more variable geochemical fluid composition. Biologically essential trace elements (such as Fe and Mn) are generally elevated in fluids of both deep and shallow hydrothermal vent fields, while vents at shallower water depth influence the photic zone more directly and thus are potentially more relevant for marine primary productivity. However, fluid flux estimations of island arc hydrothermal systems into the surrounding water column are scarce. This study (I) presents a method based on short-lived radium isotopes to estimate submarine hydrothermal discharge (SHD), (II) applies this method at Brothers volcano in the southern Kermadec arc, located northeast of New Zealand, and (III) gives dissolved Fe, Mn and He isotope flux estimates for the Earth´s longest intra-oceanic island arc, the Kermadec arc. The comparison between measured inert He isotope concentrations in the plume with calculated concentrations based on Ra isotopes matched reasonably well, which supports the use of a Ra-based discharge model. Overall, this study represents a novel approach to assess fluid and thus trace element fluxes from one hydrothermal vent field, which can be applied in future studies on various hydrothermal systems to improve geochemical models of element cycling in the ocean.