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Статті в журналах з теми "Os isotopes"
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Musich, О., A. Zubko, and О. Demyanуuk. "Isotopic effect of macro- and microelements in ecosystems." Balanced nature using, no. 4 (August 18, 2020): 132–38. http://dx.doi.org/10.33730/2310-4678.4.2020.226644.
Повний текст джерелаАнотація:
Isotopic effects occurring in living organisms due to metabolism are analyzed. The phenomenon of metabolism is considered in the classical sense as a combination of biochemical reactions (mainly enzymatic) that take place in the cells of living beings and provide the cleavage, synthesis and interconversion of complex compounds. The scope of use of natural isotopes is wide and diverse. Isotopes are carriers of information about the birth and transformation of molecules, and isotope fractionation is a chemical characteristic of a substance. Isotope metabolism consists in the intermolecular fractionation of isotopes at separate stages of biochemical reactions, namely the cleavage, synthesis and interconversion of complex compounds caused by differences in the structure and fundamental properties of isotope nuclei. It is proved that the fractionation of isotopes in chemical and biochemical reactions due to isotopic effects is based on two fundamental properties of atomic nuclei — mass and magnetic moment. The kinetic (mass-depen dent) isotopic effect distributes the isotopic nuclei by their masses, and the magnetic one fractionates the nuclei by their magnetic moments. The kinetic isotopic effect depends on the magnitude of the difference in the masses of isotopic molecules, temperature and the difference in the activation energies of isotopic forms. The magnetic isotope effect depends on the reaction rate in a single cell, its projection, magnetic moment and energy of electron-nuclear interaction. It is determined that the fractionation of isotopes in living organisms is that the relative content of one of the isotopes in this compound increases by reducing its content in the other. As a result, there is a fractionation of isotopes within one biological object.
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Li, Xiangnan, Baisha Weng, Denghua Yan, Tianling Qin, Kun Wang, Wuxia Bi, Zhilei Yu, and Batsuren Dorjsuren. "Anthropogenic Effects on Hydrogen and Oxygen Isotopes of River Water in Cities." International Journal of Environmental Research and Public Health 16, no. 22 (November 12, 2019): 4429. http://dx.doi.org/10.3390/ijerph16224429.
Повний текст джерелаАнотація:
Stable hydrogen and oxygen isotopes are important indicators for studying water cycles. The isotopes are not only affected by climate, but are also disturbed by human activities. Urban construction has changed the natural attributes and underlying surface characteristics of river basins, thus affecting the isotopic composition of river water. We collected urban river water isotope data from the Global Network for Isotopes in Rivers (GNIR) database and the literature, and collected river water samples from the Naqu basin and Huangshui River basin on the Tibetan Plateau to measure hydrogen and oxygen isotopes. Based on 13 pairs of urban area and non-urban area water samples from these data, the relationship between the isotopic values of river water and the artificial surface area of cities around rivers was analyzed. The results have shown that the hydrogen and oxygen isotope (δD and δ18O) values of river water in urban areas were significantly higher than those in non-urban areas. The isotopic variability of urban and non-urban water was positively correlated with the artificial surface area around the rivers. In addition, based on the analysis of isotope data from 21 rivers, we found that the cumulative effects of cities on hydrogen and oxygen isotopes have led to differences in surface water line equations for cities with different levels of development. The combined effects of climate and human factors were the important reasons for the variation of isotope characteristics in river water in cities. Stable isotopes can not only be used to study the effects of climate on water cycles, but also serve as an important indicator for studying the degree of river development and utilization.
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Pollard, A. M. "Isotopes and impact: a cautionary tale." Antiquity 85, no. 328 (May 2011): 631–38. http://dx.doi.org/10.1017/s0003598x00068034.
Повний текст джерелаАнотація:
There can be no doubt that isotopic studies have made a huge contribution to archaeology in recent years, so much so that isotope archaeology is now seen as an essential subdiscipline of archaeology in much the same way as isotope geochemistry is a key subdiscipline of geochemistry. Ignoring for current purposes the contribution made by the measurement of a particular radioactive isotope of carbon (14C) since 1950, we can date the beginnings of isotope archaeology to the mid 1960s with the first measurements of lead isotopes in archaeological metals and slags by Brill and Wampler (1965, 1967). This was followed by carbon stable isotopes in human bone collagen in the late 1970s, building on previous work measuring σ13C in archaeological bone for radiocarbon determinations (Vogel & Van der Merwe 1977; Van der Merwe & Vogel 1978). Other isotopes followed rapidly, such as nitrogen, oxygen, sulphur and hydrogen for archaeological, palaeoecological or palaeoclimatological purposes and, more recently, the heavier radiogenic isotopes of strontium and neodymium for determining the provenance of organic and inorganic materials (Pollard & Heron 2008).
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Miljević, Nada, and Dušan Golobočanin. "Potential Use of Environmental Isotopes in Pollutant Migration Studies." Archives of Industrial Hygiene and Toxicology 58, no. 2 (June 1, 2007): 251–62. http://dx.doi.org/10.2478/v10004-007-0015-5.
Повний текст джерелаАнотація:
Potential Use of Environmental Isotopes in Pollutant Migration StudiesThis article presents the use of natural abundance stable isotope (hydrogen, carbon, nitrogen, oxygen, chlorine) analysis data as a tool for providing important information about the origin of contaminants, the contribution of different sources to a multi-source plume, characterisation of their complex transport (rate and mechanisms) and for evaluating the success of contaminated site remediation. Isotopic signatures of contaminants are useful tracers of their sources, while isotopic fractionation can be used to quantitatively assess the progress of an environmental process such as biodegradation. This new isotopic approach is reliable and can offer more information than traditional techniques in pollutant migration studies, particularly after waste disposal. During biological degradation of any organic compound, molecules containing lighter isotopes are degraded, and the portion of heavier isotopes in the substrate is increased, identifying specific microbial roles in biogeochemical cycling. Since isotopic fractionation is proportional to degradation, depending on the type of contamination, a microbial degradation of 50% to 99% of the initial concentration can be quantified using isotope ratio measurements.
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Emmanuel, S., J. A. Schuessler, J. Vinther, A. Matthews, and F. von Blanckenburg. "A preliminary study of iron isotope fractionation in marine invertebrates (chitons, Mollusca) in near-shore environments." Biogeosciences 11, no. 19 (October 8, 2014): 5493–502. http://dx.doi.org/10.5194/bg-11-5493-2014.
Повний текст джерелаАнотація:
Abstract. Chitons (Mollusca) are marine invertebrates that produce radulae (teeth or rasping tongues) containing high concentrations of biomineralized magnetite and other iron-bearing minerals. As Fe isotope signatures are influenced by redox processes and biological fractionation, Fe isotopes in chiton radulae might be expected to provide an effective tracer of ambient oceanic conditions and biogeochemical cycling. Here, in a pilot study to measure Fe isotopes in marine invertebrates, we examine Fe isotopes in modern marine chiton radulae collected from different locations in the Atlantic and Pacific oceans to assess the range of isotopic values, and to test whether or not the isotopic signatures reflect seawater values. Values of δ56Fe (relative to IRMM-014) in chiton teeth range from −1.90 to 0.00 ‰ (±0.05‰ (2σ) uncertainty in δ56Fe), probably reflecting a combination of geographical control and biological fractionation processes. Comparison with published local surface seawater Fe isotope data shows a consistent negative offset of chiton teeth Fe isotope compositions relative to seawater. Strikingly, two different species from the same locality in the North Pacific (Puget Sound, Washington, USA) have distinct isotopic signatures. Tonicella lineata, which feeds on red algae in the sublittoral zone, has a mean δ56Fe of −0.65 ± 0.26‰ (2σ, 3 specimens), while Mopalia muscosa, which feeds on both green and red algae in the eulittoral zone, shows lighter isotopic values with a mean δ56Fe of −1.47 ± 0.98‰ (2σ, 5 specimens). Three possible pathways are proposed to account for the different isotopic signatures: (i) physiologically controlled processes within the chitons that lead to species-dependent fractionation; (ii) diet-controlled variability due to different Fe isotope fractionation in the red and green algal food sources; and (iii) environmentally controlled fractionation that causes variation in the isotopic signatures of bioavailable Fe in the different tidal regions. Our preliminary results suggest that while chitons are not simple recorders of the ambient seawater Fe isotopic signature, Fe isotopes provide valuable information concerning Fe biogeochemical cycling in near-shore environments, and may potentially be used to probe sources of Fe recorded in different organisms.
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Jensen, Alexandria, William Ford, James Fox, and Admin Husic. "Improving In-Stream Nutrient Routines in Water Quality Models Using Stable Isotope Tracers: A Review and Synthesis." Transactions of the ASABE 61, no. 1 (2018): 139–57. http://dx.doi.org/10.13031/trans.12545.
Повний текст джерелаАнотація:
Abstract. Water quality models serve as an economically feasible alternative to quantify fluxes of nutrient pollution and to simulate effective mitigation strategies; however, their applicability is often questioned due to broad uncertainties in model structure and parameterization, leading to uncertain outputs. We argue that reduction of uncertainty is partially achieved by integrating stable isotope data streams within the water quality model architecture. This article outlines the use of stable isotopes as a response variable within water quality models to improve the model boundary conditions associated with nutrient source provenance, constrain model parameterization, and elucidate shortcomings in the model structure. To assist researchers in future modeling efforts, we provide an overview of stable isotope theory; review isotopic signatures and applications for relevant carbon, nitrogen, and phosphorus pools; identify biotic and abiotic processes that impact isotope transfer between pools; review existing models that have incorporated stable isotope signatures; and highlight recommendations based on synthesis of existing knowledge. Broadly, we find existing applications that use isotopes have high efficacy for reducing water quality model uncertainty. We make recommendations toward the future use of sediment stable isotope signatures, given their integrative capacity and practical analytical process. We also detail a method to incorporate stable isotopes into multi-objective modeling frameworks. Finally, we encourage watershed modelers to work closely with isotope geochemists to ensure proper integration of stable isotopes into in-stream nutrient fate and transport routines in water quality models. Keywords: Isotopes, Nutrients, Uncertainty analysis, Water quality modeling, Watershed.
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Orlowski, N., P. Kraft, and L. Breuer. "Exploring water cycle dynamics through sampling multitude stable water isotope pools in a small developed landscape of Germany." Hydrology and Earth System Sciences Discussions 12, no. 2 (February 6, 2015): 1809–53. http://dx.doi.org/10.5194/hessd-12-1809-2015.
Повний текст джерелаАнотація:
Abstract. Conducting a dual stable water isotope (δ2H and δ18O) study in the developed landscape of the Schwingbach catchment (Germany) helped to unravel connectivity and disconnectivity between the different water cycle components. The two-year weekly to biweekly measurements of precipitation, stream, and groundwater isotopes revealed that surface and groundwater are decoupled from the annual precipitation cycle but showed bidirectional interactions between each other. Seasonal variations based on temperature effects were observed in the precipitation signal but neither reflected in stream nor in groundwater isotopic signatures. Apparently, snowmelt played a fundamental role for groundwater recharge explaining the observed differences to precipitation δ-values. A spatially distributed snapshot sampling of soil water isotopes in two soil depths at 52 sampling points across different land uses (arable land, forest, and grassland) revealed that top soil isotopic signatures were similar to the precipitation input signal. Preferential water flow paths occurred under forested soils explaining the isotopic similarities between top and subsoil isotopic signatures. Due to human-impacted agricultural land use (tilling and compression) of arable and grassland soils, water delivery to the deeper soil layers was reduced, resulting in significant different isotopic signatures. However, the land use influence smoothed out with depth and soil water approached groundwater δ-values. Seasonally tracing stable water isotopes through soil profiles showed that the influence of new percolating soil water decreased with depth as no remarkable seasonality in soil isotopic signatures was obvious at depth > 0.9 m and constant values were observed through space and time. Little variation in individual isotope time series of stream and groundwater restricted the use of classical isotope hydrology techniques e.g. mean transit time estimation or hydrograph separation. Still, tracing stable water isotopes through the water cycle was valuable for determining interactions between different water cycle components and gaining catchment specific process understanding in a developed, human-impacted landscape.
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Emmanuel, S., J. A. Schuessler, J. Vinther, A. Matthews, and F. von Blanckenburg. "Iron isotope fractionation in marine invertebrates in near shore environments." Biogeosciences Discussions 11, no. 4 (April 11, 2014): 5533–55. http://dx.doi.org/10.5194/bgd-11-5533-2014.
Повний текст джерелаАнотація:
Abstract. Chitons (Mollusca) are marine invertebrates that produce radula (teeth or rasping tongue) containing high concentrations of biomineralized magnetite and other iron bearing minerals. As Fe isotope signatures are influenced by redox processes and biological fractionation, Fe isotopes in chiton radula might be expected to provide an effective tracer of ambient oceanic conditions and biogeochemical cycling. Here, in a pilot study to measure Fe isotopes in marine invertebrates, we examine Fe isotopes in modern marine chiton radula collected from different locations in the Atlantic and Pacific oceans to assess the range of isotopic values, and to test whether or not the isotopic signatures reflect seawater values. Furthermore, by comparing two species that have very different feeding habits but collected from the same location, we infer a possible link between diet and Fe isotopic signatures. Values of δ56Fe (relative to IRMM-014) in chiton teeth range from −1.90 to 0.00‰ (±0.05‰ (2σ) uncertainty in δ56Fe), probably reflecting a combination of geographical control and biological fractionation processes. Comparison with published local surface seawater Fe isotope data shows a consistent negative offset of chiton teeth Fe isotope compositions relative to seawater. Strikingly, two different species from the same locality in the North Pacific (Puget Sound, Washington, USA) have distinct isotopic signatures. Tonicella lineata, which feeds on red algae, has a mean δ56Fe of −0.65 ± 0.26‰ (2σ, 3 specimens), while Mopalia muscosa, which feeds primarily on green algae, shows lighter isotopic values with a mean δ56Fe of −1.47 ± 0.98‰ (2σ, 5 specimens). Although chitons are not simple recorders of the ambient seawater Fe isotopic signature, these preliminary results suggest that Fe isotopes provide information concerning Fe biogeochemical cycling in near shore environments, and might be used to probe sources of Fe in the diets of different organisms.
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Fujii, T., F. Moynier, A. Agranier, E. Ponzevera, and M. Abe. "Isotope fractionation of palladium in chemical exchange reaction." Proceedings in Radiochemistry 1, no. 1 (September 1, 2011): 339–44. http://dx.doi.org/10.1524/rcpr.2011.0060.
Повний текст джерелаАнотація:
Abstract Palladium isotopes were fractionated by the solvent extraction technique with a crown ether. After purification by ion-exchange chemistry, the isotopic ratios of 105Pd/106Pd, 108Pd/106Pd, and 110Pd/106Pd were determined by multiple-collector inductively coupled plasma mass spectrometry. Isotope fractionations between the two phases were found to be larger than 0.1‰. The isotope fractionation of the odd atomic mass isotope (105Pd) showed a deviation from that estimated from the even atomic mass isotopes (106Pd, 108Pd, and 110Pd). The mass-independent isotope fractionation found was attributable to the nuclear field shift effect. The quantum chemical calculations for the different Pd species supported the validity of the isotope fractionation factors obtained.
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Passey, Benjamin H. "Reconstructing Terrestrial Environments Using Stable Isotopes in Fossil Teeth and Paleosol Carbonates." Paleontological Society Papers 18 (November 2012): 167–94. http://dx.doi.org/10.1017/s1089332600002606.
Повний текст джерелаАнотація:
Carbon isotopes in Neogene-age fossil teeth and paleosol carbonates are commonly interpreted in the context of past distributions of C3 and C4 vegetation. These two plant types have very different distributions in relation to climate and ecology, and provide a robust basis for reconstructing terrestrial paleoclimates and paleoenvironments during the Neogene. Carbon isotopes in pre-Neogene fossil teeth are usually interpreted in the context of changes in the δ13C value of atmospheric CO2, and variable climate-dependent carbon-isotope discrimination in C3 plants. Carbon isotopes in pre-Neogene soil carbonates can be used to estimate past levels of atmospheric CO2. Oxygen isotopes in fossil teeth and paleosol carbonates primarily are influenced by the oxygen isotopic compositions of ancient rainfall and surface waters. The oxygen isotopic composition of rainfall is has a complex, but tractable, relationship with climate, and variably relates to temperature, elevation, precipitation amount, and other factors. Mammal species that rely on moisture in dietary plant tissues to satisfy their water requirements (rather than surface drinking water) may have oxygen isotopic compositions that track aridity. Thus, oxygen isotopes of fossil mammals can place broad constraints on paleoaridity. Carbonate clumped isotope thermometry allows for reconstruction of soil temperatures at the time of pedogenic carbonate mineralization. The method is unique because it is the only thermodynamically based isotopic paleothermometer that does not require assumptions about the isotopic composition of the fluid in which the archive mineral formed. Soil temperature reflects a complex interplay of air temperature, solar radiative heating, latent heat effects, soil thermal diffusivity, and seasonal variations of these parameters. Because plants and most animals live in and/or near the soil, soil temperature is an important aspect of terrestrial (paleo)climate.
Дисертації з теми "Os isotopes"
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Nilsson, Lino. "Nitrogen transformations at the Kiruna mine : The use of stable nitrogen isotopes to trace nitrogen-transforming processes." Thesis, Uppsala universitet, Luft-, vatten och landskapslära, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-209419.
Повний текст джерелаАнотація:
Release of different nitrogen compounds can cause eutrophication in lakes and rivers whichcan lead to oxygen-free environments in bottom water and in the sediment and can in turnlead to fish-deaths. Ammonium can be toxic to biota and nitrate can in high concentrationeven be toxic to humans. WHO has released a limit for nitrate concentration in drinking waterof 10mg/l. The LKAB mine in Kiruna is the largest underground iron mine in the world and isprospecting, mining and refining iron ore, with an annual production of around 28 milliontons. Release of different nitrogen compounds as a result of the explosives used during themining operations has been a known problem for some time; however the processes affectingnitrogen during the water transport have never been fully investigated. The main objective of this MSc thesis is to determine if changes in nitrogen and oxygenisotope composition can be used as a tracer for nitrogen transformation processes in the minewater at LKABs underground mine in Kiruna. Water samples were collected at key points in the water transport system and were analyzedfor isotopic composition. Isotopic and chemical data revealed two different sources of nitrateand ammonium, undetonated explosives and leachate from waste rocks. Three differentnitrogen changing processes affecting concentration of nitrate and ammonium were found:ammonium volatilization, nitrification and sorption. It was not possible to quantify theseprocesses individually. No processes which decrease the nitrate concentration were found.
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Dubeau, Jacques. "Isotope shift measurements of the stable krypton isotopes in natural and enriched concentrations." Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66154.
Повний текст джерела
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Vaiglova, Petra. "Neolithic agricultural management in the Eastern Mediterranean : new insight from a multi-isotope approach." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:c8824136-da35-43b2-a700-f458d0cc2fdf.
Повний текст джерелаАнотація:
The work presented in this dissertation explores the nature of agro-pastoral strategies developed by Neolithic farmers as a way to understand how early food production was inter-twined with environmental and socio-economic opportunities and constraints. Towards this end, a multi-isotope approach is used to address questions of scale and intensity of crop cultivation and animal management at the archaeological sites of Kouphovouno, southern Greece, Makriyalos, northern Greece, and Çatalhöyük, south-central Turkey. Measurements of stable carbon, nitrogen, oxygen and strontium isotope values of carbonized plant remains, human and animal bone collagen and animal tooth enamel are used to examine the similarities and differences in the types of treatments that individual species of plants and animals received during the agricultural cycle at the distinct locations. The results show that farmers at the three sites developed variable methods for exploiting the arable and pastoral landscape and catering to their economic and culinary needs. The discussion considers the implications of these findings to our understanding of the complexity and adaptability of early farming systems.
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Móri, Cleusa [UNESP]. "Rastreabilidade de farinhas de origem animal em tecidos de codornas de corte pela técnica dos isótopos estáveis de carbono ('intpot.13C'/'intpot.12C') e nitrogênio ('intpot.15N'/'intpot.14N')." Universidade Estadual Paulista (UNESP), 2007. http://hdl.handle.net/11449/104988.
Повний текст джерелаАнотація:
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Universidade Estadual Paulista (UNESP)
Estudos para detecção de subprodutos de origem animal em carne de aves são escassos e, em se tratando de codornas são inexistentes. O trabalho teve por objetivo a detecção de farinha de vísceras de aves (FVA) em dietas de codornas de corte no músculo peitoral quilha e tíbia pela técnica dos isótopos estáveis de carbono (13C/12C) e nitrogênio (15N/14N). Foram utilizadas 64 codornas de corte macho de um dia de idade advindas de granja comercial. As aves foram divididas em sete grupos distintos distribuídos aleatoriamente em relação às dietas experimentais que continham diferentes percentagens de FVA: 0; 1,5; 3,0; 4,5; 6,0; 7,5 e 15. As dietas foram formuladas de forma a serem isoenergéticas, isoprotéicas e isoaminoacídicas. Quatro aves de cada tratamento foram abatidas aos 42 dias de idade para colheita do músculo peitoral (Pectoralis major), quilha e tíbia para posteriormente serem analisadas. Observou-se enriquecimento isotópico de d13C e d15N nos três tecidos analisados. Em codornas de corte com 42 dias de idade, o nível de inclusão de farinha de vísceras de aves detectado compreende o intervalo de 3,0 a 4,5%.
Detection of animal origin by-products studies in poultry meat are rare and inexistent when related to quail meat. This paper aims the detection of increasing levels of poultry visceral meal (FVA) in quail meat, using carbon (13C/12C) and nitrogen (15N/14N) stable isotopes technique. Sixty four male quails aging one day originally from a commercial producer were divided in seven different groups in a random distribution. Those groups received different experimental diets containing 0; 1,5; 3,0; 4,5; 6,0; 7,5 e 15% of FVA. Those diets were formulated to be isoenergetic, isoproteic and to have the same level of amino-acids. Four individuals per treatment were sacrificed at the 42nd day for breast muscle (Pectoralis major), keel and tibia collection to later analysis. Isotopic enrichment of d13C and d15N were observed in all analyzed tissues. In 42 day old quail were detect a 3,0 and 4,5% poultry visceral meal inclusion in its diet.
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Móri, Cleusa 1974. "Rastreabilidade de farinhas de origem animal em tecidos de codornas de corte pela técnica dos isótopos estáveis de carbono ('intpot.13C'/'intpot.12C') e nitrogênio ('intpot.15N'/'intpot.14N') /." Botucatu : [s.n.], 2007. http://hdl.handle.net/11449/104988.
Повний текст джерелаАнотація:
Orientador: Edivaldo Antônio GarciaBanca: Ricardo de Albuquerque
Banca: Carla Cachoni Pizzolante
Banca: Carlos Ducatti
Banca: Ariel Antonio Mendes
Resumo: Estudos para detecção de subprodutos de origem animal em carne de aves são escassos e, em se tratando de codornas são inexistentes. O trabalho teve por objetivo a detecção de farinha de vísceras de aves (FVA) em dietas de codornas de corte no músculo peitoral quilha e tíbia pela técnica dos isótopos estáveis de carbono (13C/12C) e nitrogênio (15N/14N). Foram utilizadas 64 codornas de corte macho de um dia de idade advindas de granja comercial. As aves foram divididas em sete grupos distintos distribuídos aleatoriamente em relação às dietas experimentais que continham diferentes percentagens de FVA: 0; 1,5; 3,0; 4,5; 6,0; 7,5 e 15. As dietas foram formuladas de forma a serem isoenergéticas, isoprotéicas e isoaminoacídicas. Quatro aves de cada tratamento foram abatidas aos 42 dias de idade para colheita do músculo peitoral (Pectoralis major), quilha e tíbia para posteriormente serem analisadas. Observou-se enriquecimento isotópico de d13C e d15N nos três tecidos analisados. Em codornas de corte com 42 dias de idade, o nível de inclusão de farinha de vísceras de aves detectado compreende o intervalo de 3,0 a 4,5%.
Abstract: Detection of animal origin by-products studies in poultry meat are rare and inexistent when related to quail meat. This paper aims the detection of increasing levels of poultry visceral meal (FVA) in quail meat, using carbon (13C/12C) and nitrogen (15N/14N) stable isotopes technique. Sixty four male quails aging one day originally from a commercial producer were divided in seven different groups in a random distribution. Those groups received different experimental diets containing 0; 1,5; 3,0; 4,5; 6,0; 7,5 e 15% of FVA. Those diets were formulated to be isoenergetic, isoproteic and to have the same level of amino-acids. Four individuals per treatment were sacrificed at the 42nd day for breast muscle (Pectoralis major), keel and tibia collection to later analysis. Isotopic enrichment of d13C and d15N were observed in all analyzed tissues. In 42 day old quail were detect a 3,0 and 4,5% poultry visceral meal inclusion in its diet.
Doutor
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Petitat, Manuel. "Cr isotopes in carbonaceous chondrites : 53Mn-53Cr systematics and Cr isotopic anomalies." Paris, Muséum national d'histoire naturelle, 2010. http://www.theses.fr/2010MNHN0017.
Повний текст джерелаАнотація:
Cette thèse comporte deux parties distinctes. Dans la première partie, la systématique 53Mn-53Cr a été développée sur une NanoSIMS 50 et une CAMECA IMS 1270 pour dater la formation de carbonates dans les météorites Orgueil, Alais, Boriskino et Kaidun. Dans chaque grain, les excès en 53Cr mesurés corrèlent linéairement avec leurs rapports élémentaires 55Mn/52Cr ratios mesurés, indiquant la décroissance in-situ de 53Mn et donc la présence de 53Mn lorsque le grain a cristallisé. Dans la deuxième partie, un fragment de Tagish Lake et d’Orgueil ont été dissouts en 5 étapes afin d’identifier les phases minérales porteuses d’anomalies en Cr. Nos résultats montrent que Tagish Lake présente les plus grands excès et déficits en 54Cr par rapport au standard terrestre de toutes les chondrites carbonées analysées à ce jour faisant de cette météorite une des moins métamorphisée ainsi qu’une candidate idéale pour trouver la phase porteuse de l’anomalie en 54Cr, elle encore inconnueThis thesis has 2 distinct parts. In part I, the 53Mn-53Cr systematics was developed on a NanoSIMS and a CAMECA IMS 1270 to date the formation of carbonates in Orgueil, Alais, Boriskino and Kaidun. For each grain, the 53Cr excesses measured linearly correlated with their respective 55Mn/52Cr ratios, indicating the in-situ decay of 53Mn and showing that 53Mn was still extent at the time of formation of the respective carbonate. In part II, fragments of Tagish Lake and of Orgueil were dissolved in 5 different steps by using reagents with increasing acid strength to identify the different mineral phases carrying the Cr anomalies. Our results show that Tagish Lake displays both the highest excess and the highest deficit in 54Cr relative to a terrestrial standard of all groups of carbonaceous chondrite meteorites. This makes this meteorite one of the least metamorphic meteorite present in the collections worldwide and a particular target for deciphering the carrier phase of the 54Cr anomaly
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Perez, Fernandez Andrea. "Etude expérimentale sur l'échange isotopique dans le système eau-roches carbonatées." Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30398.
Повний текст джерелаАнотація:
Les signatures isotopiques des minéraux carbonatés sont utilisées pour caractériser de nombreux processus géochimiques. Cette thèse a pour but de déterminer les vitesses auxquelles ces signatures isotopiques peuvent être altérées lors des interactions entre les fluides et les minéraux. A cette fin, une série d'études expérimentales a été conduite avec la dolomite (CaMg(CO3)2), la magnésite (MgCO3) et la calcite (CaCO3). On a mesuré l'évolution temporelle des compositions isotopiques de Ca et Mg pendant une série d'expériences de dissolution en réacteur fermé de la dolomite à des températures de 50°C à 126°C. A T < 120°C la composition isotopique du calcium dans la phase fluide est identique à celle de la dolomite initiale, mais au-delà de cette température, la signature isotopique du calcium dans le fluide (delta(44/42)Ca fluid) après 4 semaines était 0.6±0.1‰ plus lourde que l'originale. En revanche, le rapport delta(26/24)Mg du fluide reste égal à celui de la dolomite à toutes les températures étudiées. Ces résultats indiquent un double transfert de calcium vers et depuis la structure de la dolomite à T > 120°C. En outre, ces résultats suggèrent que la difficulté de la dolomite à précipiter à température ambiante doit être la conséquence de l'incapacité de Mg à s'incorporer dans la structure du minéral. Dans une autre étude on a conduit des expériences de dissolution de la magnésite à 25°C en solution aqueuses pour différents pH et pression de CO2. On a trouvé que la composition isotopique du fluide à proximité de l'équilibre chimique était différente de celle du solide, ce qui reflète un double transfert de Mg en direction et hors du minéral à température ambiante. Cependant, un seul mécanisme de fractionnement ne peut expliquer le comportement isotopique de Mg observé. La dernière partie de ce travail, consacrée au fractionnement isotopique du carbone dans le système calcite-eau, montre une évolution du fractionnement isotopique de cet élément vers le fractionnement isotopique à l'équilibre d'une durée d'une année après l'atteinte de l'équilibre chimique entre la calcite et l'eau. Les vitesses de rééquilibrage des isotopes de carbone sont ainsi quatre ordres de grandeurs plus lentes que la vitesse d'équilibrage de la calcite avec la solution. Ceci suggère que l'étape limitante dans le processus de rééquilibrage des isotopes du carbone est le transport de cet élément dans le cristal après l'échange isotopique à la surface de ce dernier. Les résultats de cette thèse indiquent que la signature isotopique de Mg, Ca et C des carbonates n'est pas invariante à l'échelle des temps géologiques et qu'elle peut être altérée durant l'interaction de ces minéraux avec l'eau. Ainsi, la préservation des signatures isotopiques des carbonates requiert d'une faible perméabilité des roches ou bien quelque mécanisme inhibant les échanges des métaux et du carbone à la surface des cristauxThe isotopic signatures of carbonate minerals have been applied to illuminate a plethora of natural geochemical processes. This thesis is aimed to assess the rates and or conditions at which such isotope signatures might be altered by fluid-mineral interaction through a series of systematic experimental studies performed with dolomite (CaMg(CO3)2) magnesite (MgCO3) and calcite (Ca-CO3). Ca and Mg isotopic compositions were measured as a function of time during closed-system stoichiometric dolomite dissolution experiments at 50 to 126°C. Although identical to that of the original dolomite at low temperatures, at temperatures >120 °C, the calcium isotopic signature of fluid phase (delta(44/42)Ca fluid) became 0.6±0.1‰ higher than that of the dissolving dolomite over a 4-week period. In contrast, the delta(26/24)Mg fluid, remained equal to that of the dolo-mite both at low and high temperatures. This set of experiments evidences the two-way transfer of calcium in and out of the dolomite structure at elevated temperatures. The results suggest that the inhability of dolomite to precipitate at these conditions is due to the difficulty of Mg to be reincorporated in the dolomite structure. In a follow-up study, magnesite was dissolved at 25°C in the presence of fluids with distinct pH and CO2 pressures. The isotopic compositions of the fluid differed from that of the solid at near-to chemical equilibrium indicating the two-way transfer of magnesium into this mineral at ambient temperatures. A single fractionation mechanism cannot explain the distinct Mg isotope behaviors observed. Further work on carbon isotope exchanges in the calcite water system shows a slow by steady evolution of the carbon isotopic composition towards the accepted equilibrium fractionation factor over the course of nearly year-long experiments after the system had attained bulk chemical equilibrium. Carbon isotope reequilibration rates were found to be approximately four orders of magnitude slower than that of bulk calcite dissolution, suggesting that the rate limiting step to the carbon isotope reequilibration process is the transport of carbon into and out of the bulk mineral after it has exchanged on the surface. The results of this thesis suggest that the Mg, Ca and C isotopic signatures in carbonate minerals are not invariant over geological time-frames and can be readily altered by water-mineral interaction. Such results indicate that the preservation of carbonate mineral signatures require low permeability rock formations or some inhibitory mechanism limiting metal and carbon exchange
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Suzuki, Rafael Massami. "Aminoácidos marcados aplicados aos estudos de nutrição e fisiologia em frangos de corte /." Jaboticabal, 2019. http://hdl.handle.net/11449/191289.
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Orientador: Nilva Kazue SakomuraResumo: RESUMO: A evolução das análises, considerando especificamente a nutrição e fisiologia de frangos de corte, permitiram rastrear nutrientes a níveis nucleares, permitindo que novas metodologias fossem desenvolvidas e novos objetivos alcançados. Algumas das análises que merecem destaque considerando estudos voltados a exigências de aminoácidos e metabolismo proteico foram: determinação de nitrogênio total/proteína, análise da composição aminoacídica e análise isotópica, sendo que a associação destas análises permite um potencial ainda maior. O uso de compostos enriquecidos é uma excelente ferramenta para estudos fisiológicos, uma vez que as respostas obtidas são inerentes ao composto de interesse, sendo possível o rastreamento do isótopo. Contudo, esta tecnologia ainda apresenta um alto custo, parte devido à baixa produção destes produtos e devido o sigilo da tecnologia da produção de tais compostos. Deste modo, no capítulo 2 foi padronizado uma metodologia para avaliar a adição de aminoácido marcado na dieta de aves e sua incorporação nos tecidos. A seguir, no capítulo 3 é apresentado um estudo com o objetivo de fracionar a utilização dos aminoácidos sulfurados com a utilização de metionina e cistina marcadas, avaliando-se diferentes proporções de ambos aminoácidos e diferentes fontes de metionina. Por fim, no capitulo 4 foi avaliado o efeito da idade sob a incorporação da L-(15N) treonina em diferentes tecidos de frangos de corte. Portanto, os objetivos desta tese foram a padr... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: ABSTRACT: The evolution of the analyzes, specifically regarding nutrition and physiology of broiler chickens, allowed to track nutrients to nuclear levels, resulting in the development of new methodologies and new objectives were achieved. Some of the analyzes that deserve to be highlighted considering amino acid requirements and protein metabolism studies were: total nitrogen/protein determination, amino acid composition analysis and isotopic analysis, and the association of these analyzes allows an even greater potential. The use of enriched compounds is an excellent tool for physiological studies, since the responses obtained are inherent to the compound of interest, and it is possible to track the tracer. However, the cost of such technology is still high, partly due to the low production of these products and also due to the secrecy of the technology of the production of such compounds. Thus, in chapter 2, a methodology was standardized in order to evaluate the addition of labeled amino acid in the broiler diet and its incorporation into tissues. In addition, chapter 3 presents a study in order to fractionate the use of sulfur amino acids using labeled methionine and cystine, and evaluating different proportions of both amino acids and different sources of methionine. Finally, in chapter 4, the effect of age on the incorporation of L-(15N) threonine into different broiler tissues was evaluated. Therefore, the objectives of this thesis were the standardization and applica... (Complete abstract click electronic access below)
Doutor
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Swift, Benjamin. "The use of radio-isotopes in forensic science : the development of the isotope fingerprint analysis." Thesis, University of Leicester, 2004. http://hdl.handle.net/2381/29475.
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It is generally accepted that remains should be no more than 75 years old to warrant police interest. Therefore any reliable dating method should distinguish bones from within this interval accurately from those lying outside of it. Although archaeologists have reliable tools for dating material, pathologists have been unable to devise a method that caters for their specific needs. Previous work has focused upon the physiochemical properties of bone or its organic constituents, though the results have failed to produce a workable calibration system. The first hypothesis of this thesis has confirmed the existence of a predictable and measurable relationship between specific radioisotope concentrations in human bone and the post-mortem interval (PMI). It is predicted that the relationship is such that, once a calibration system has been created, it is possible to accurately estimate the PMI in a set of remains of unknown antiquity. Though concentrating upon 210Pb activities, the study also evaluated additional commonly occurring nuclides, both natural and man-made, the latter being subsequent to nuclear experimentation. The second confirmed hypothesis is that the geographical region an individual lived within becomes imprinted within their skeletal system, such that recognisable relationships between isotopes exist, creating a radio-isotope fingerprint. Examination of these relationships allows identification of the country in which a decedent lived.
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Huckle, David Martyn. "Characterizing U-series Isotope Signatures in Soils and Headwater Streams in a Complex Volcanic Terrain: Jemez River Critical Zone Observatory, Valles Caldera, NM." Thesis, The University of Arizona, 2013. http://hdl.handle.net/10150/305863.
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Uranium-series isotopes are an emerging tool to characterize weathering and soil forming processes in the Critical Zone, the dynamic region of earth's surface where bedrock, water, soil, and life chemically and physically interact to support ecosystems. Understanding controls on the U-series composition of soils across a range of lithologies and climate is critical to applying existing mass balance models of U-series isotopes to calculate soil formation rates in these systems. This study seeks to understand the behavior of U-series isotopes in soil profiles in the semi-arid complex volcanic terrain of the Valles Caldera, NM. (²³⁴U/²³⁸U) measured in soils ranged from 0.90 to 1.56 and (²³⁰Th/²³⁸U) values ranged from 0.48 to 1.39. Significant ²³⁰Th enrichment in upper soil profiles was interpreted as evidence of mixing with ²³⁰Th-enriched volcanic ash and significant ²³⁴U enrichment in one soil profile was interpreted as evidence of addition of U to soils from ²³⁴U-enriched soil solutions. A simple U isotope mass balance model was applied to estimate soil residence time based on U addition, which yielded a minimum residence time of ~10ka. Evidence of past episodic mixing of volcanic ash in these soils suggests modeling soil formation using a mass balance approach is problematic, and future applications of existing models in other heterogeneous volcanic soils should be applied cautiously. U-series isotopes have also shown promise as a tracer of residence time in shallow groundwater and streams. In this study, (²³⁴U/²³⁸U) in dissolved U is used to trace seasonal variation in source water contributions to streamflow in a small (3.29km²), headwater catchment in the Jemez River Basin Critical Zone Observatory within the Valles Caldera. Systematically lower (²³⁴U/²³⁸U) values in dissolved U were observed in spring and stream waters in conjunction with greater contributions of longer residence time waters during snowmelt ((²³⁴U/²³⁸U) ranged 1.7 to 2.8) vs. dry seasons ((²³⁴U/²³⁸U) ranged 1.9 to 3.1). The lower (²³⁴U/²³⁸U) values in longer residence time waters were attributed to progressive depletion of easily-weathered ²³⁴U with increasing duration of water rock interaction. Further studies with more quantitative age tracers, such as ³H, could help to establish (²³⁴U/²³⁸U) values as a powerful tracer of water sources and residence time in streamwaters at the catchment scale.
Книги з теми "Os isotopes"
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Arnikar, Hari Jeevan. Isotopes in the atomic age. New Delhi: Wiley Eastern, 1989.
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Isotopes in the atomic age. New York: Wiley, 1989.
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3
Marschall, Horst, and Gavin Foster, eds. Boron Isotopes. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-64666-4.
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Tom, Edwards, Kull Christoph, and Alverson Keith, eds. Stable isotopes. Bern, Switzerland: PAGES International Project Office, 2002.
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5
M, Johnson Clark, Beard Brian L, Albarède Francis, American Geophysical Union Meeting, and Canadian Geophysical Union Meeting, eds. Geochemistry of non-traditional stable isotopes. Washington, DC: Mineralogical Society of America, 2004.
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M, Andreev B., ed. Separation of isotopes of biogenic elements in two-phase systems. Amsterdam: Elsevier, 2007.
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Firestone, Richard B. Table of isotopes. Edited by Shirley Virginia S. 8th ed. New York: Wiley, 1996.
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William, Walker F., Parrington Josef R, Feiner Frank, and General Electric Company, eds. Nuclides and isotopes. San Jose, Calif: General Electric Co., 1989.
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Firestone, Richard B. Table of isotopes. Edited by Baglin Coral M. 1939-. 8th ed. New York: Wiley, 1998.
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Bowen, Robert. Isotopes and climates. London: Elsevier Applied Science, 1991.
Знайти повний текст джерелаЧастини книг з теми "Os isotopes"
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Werner, Roland A., and Marc-André Cormier. "Isotopes—Terminology, Definitions and Properties." In Stable Isotopes in Tree Rings, 253–89. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-92698-4_8.
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AbstractThe intention of this chapter is to give insight into the properties and peculiarities of the stable isotopes of the bioelements. Following an overview about the terminology and ʻtechnical jargonʼ used in stable isotope sciences, methods to calculate and express isotopic abundances are presented. Subsequently, a short description of the physicochemical basis of equilibrium and kinetic (mass-dependent) isotope effects (EIEs and KIEs) as origin of isotope fractionation in chemical and biological systems is given. Further, measures for calculation and presentation of isotope fractionation are introduced and the corresponding properties of these quantities are critically discussed. Finally, examples for equilibrium and kinetic isotope fractionation in biochemical reactions are presented in more details and subsequent effects and consequences including the relationship between EIEs and KIEs are reviewed.
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Kagawa, Akira, and Giovanna Battipaglia. "Post-photosynthetic Carbon, Oxygen and Hydrogen Isotope Signal Transfer to Tree Rings—How Timing of Cell Formations and Turnover of Stored Carbohydrates Affect Intra-annual Isotope Variations." In Stable Isotopes in Tree Rings, 429–62. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-92698-4_15.
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AbstractIn this chapter, we discuss post-photosynthetic processes that affect intra-annual variation in the stable isotopes of tree rings, such as timing of cell formations and turnover of stored carbohydrates, by combining research findings gained by using either natural-abundance or artificially-enriched carbon, oxygenand hydrogen isotopes. We focus on within-ring variation in stable isotope ratios, with an emphasis on aligning observed ratios in whole wood or extracted cellulose to seasonal dynamics in climate and phenology. We also present a discussion of isotopic fractionation that operates within the scope of observed variations across individual rings. We then introduce a model that traces the seasonal partitioning of photosynthate into tree rings via storage pool, which is based on experimental data gained from labeling studies using artificially enriched 13CO2 gas. Finally, we will describe our current understanding of post-photosynthetic signal transfer processes of oxygenand hydrogen isotopes from leaves to tree rings, such as exchange of oxygen and hydrogen between storage carbohydrates and local cambial water, and possible causes of difference in oxygen and hydrogen isotope fractionations. Finally, we discuss mechanisms behind how oxygen and hydrogen from foliar-absorbed liquid water is then incorporated into wood biomass, by introducing results gained from recent H218O and HDO pulse-labeling experiments.
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Kagawa, Akira, and Giovanna Battipaglia. "Post-photosynthetic Carbon, Oxygen and Hydrogen Isotope Signal Transfer to Tree Rings—How Timing of Cell Formations and Turnover of Stored Carbohydrates Affect Intra-annual Isotope Variations." In Stable Isotopes in Tree Rings, 429–62. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-92698-4_15.
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AbstractIn this chapter, we discuss post-photosynthetic processes that affect intra-annual variation in the stable isotopes of tree rings, such as timing of cell formations and turnover of stored carbohydrates, by combining research findings gained by using either natural-abundance or artificially-enriched carbon, oxygenand hydrogen isotopes. We focus on within-ring variation in stable isotope ratios, with an emphasis on aligning observed ratios in whole wood or extracted cellulose to seasonal dynamics in climate and phenology. We also present a discussion of isotopic fractionation that operates within the scope of observed variations across individual rings. We then introduce a model that traces the seasonal partitioning of photosynthate into tree rings via storage pool, which is based on experimental data gained from labeling studies using artificially enriched 13CO2 gas. Finally, we will describe our current understanding of post-photosynthetic signal transfer processes of oxygenand hydrogen isotopes from leaves to tree rings, such as exchange of oxygen and hydrogen between storage carbohydrates and local cambial water, and possible causes of difference in oxygen and hydrogen isotope fractionations. Finally, we discuss mechanisms behind how oxygen and hydrogen from foliar-absorbed liquid water is then incorporated into wood biomass, by introducing results gained from recent H218O and HDO pulse-labeling experiments.
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Andreu-Hayles, Laia, Mathieu Lévesque, Rossella Guerrieri, Rolf T. W. Siegwolf, and Christian Körner. "Limits and Strengths of Tree-Ring Stable Isotopes." In Stable Isotopes in Tree Rings, 399–428. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-92698-4_14.
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AbstractThis chapter aims at summarizing strengths and caveats on the suitability of stable carbon and oxygen isotopes in tree rings as recorders for fingerprints of environmental influences. First, environmental constraints limiting tree growth and shaping tree species distribution worldwide are discussed. Second, examples are presented for environmental conditions under which tree-ring isotopes record environmental signals particularly well, but also cases where physiological processes can mask climate signals. Third, the link between leaf-level carbon assimilation and the investment of assimilates in the stem during the annual ring formation are discussed in light of the resulting deviations of the isotopic values between leaves and tree rings. Finally, difficulties and pitfalls in the interpretation of stable isotope signals in tree rings are reviewed. These problems often result from a poor understanding of when and how the tree canopy, stems and roots are physiologically interconnected. Current literature suggests that photosynthesis and radial growth are only loosely coupled, if at all, challenging the interpretation of environmental signals recorded in tree-ring isotopes. Harsh environmental conditions (e.g. low temperatures, drought) often result in a decoupling of carbon assimilation and growth. The chapter closes by providing possible solutions on how to improve the detection of environmental information from stable isotope signals by integrating scales and different methodological approaches.
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Pfahler, V., J. Adu-Gyamfi, D. O’Connell, and F. Tamburini. "The Use of the δ18OP to Study P Cycling in the Environment." In Oxygen Isotopes of Inorganic Phosphate in Environmental Samples, 1–15. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-97497-8_1.
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AbstractPhosphorus (P) fertilizers are known to increase crop productivity; however, when applied in excess, it can cause serious environment pollution. Monitoring P pollution in natural environments using stable isotopes has been difficult because P has only one stable isotope (31P) making the use of P stable isotope tracing not an option. Radioactive P isotopes (32P and 33P) have been used but its drawbacks are the short half-life, health risks and safety procedures required to apply them in agricultural catchments. Phosphorus in organic and inorganic P forms is strongly bonded to oxygen (O), which has three stable isotopes, providing a system to track P cycling in agricultural catchments and environment using the stable isotopes of O in phosphate (δ18O-PO4). In recent years, various studies have indicated that the analysis of the stable isotopic composition of oxygen (O) bound to P (δ18Op) to better understand P cycling in the environment, has become a promising tracer (surrogate) to investigate soil P transformation, plant P uptake and to trace the sources of P from the soil to water bodies and the environment. The chapter outlines the background and examples of δ18Op studies in sediments, soils, fresh water, mineral fertilizers and plants.
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Helle, Gerhard, Maren Pauly, Ingo Heinrich, Karina Schollän, Daniel Balanzategui, and Lucas Schürheck. "Stable Isotope Signatures of Wood, its Constituents and Methods of Cellulose Extraction." In Stable Isotopes in Tree Rings, 135–90. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-92698-4_5.
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AbstractIn this chapter, we give some basic information on the chemical and isotopic properties of wood constituents and describe their relative contribution to the isotopic signature of wood. Based on these considerations we review studies that have compared stable isotope signals of wood with those of corresponding cellulose. We exemplify how relationships of wood-based tree-ring stable isotope sequences with climate can be affected by varying proportions of wood constituents like cellulose, lignin and extractives. A majority of benchmarking studies suggests that cellulose extraction may not be necessary. However, based upon existing research, a general statement cannot be made on the necessity of cellulose extraction. Changes in wood composition can particularly influence environmental signal strength during periods of low isotope variability. Cellulose extraction removes any effects from changing wood composition. We present the three established chemical approaches of extraction, outline how to test the purity of isolated cellulose and present user-friendly efficient experimental setups allowing to simultaneously process hundreds of samples in one batch. Further, we briefly address the analysis of stable isotopes of lignin methoxyl groups because of easy sample preparation and its potential additional value for studies on fossil wood.
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Wei, Liang, John D. Marshall, and J. Renée Brooks. "Process-Based Ecophysiological Models of Tree-Ring Stable Isotopes." In Stable Isotopes in Tree Rings, 737–56. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-92698-4_26.
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AbstractTree-ring stable isotopes can be used to parameterizeprocess-based models by providing long-term data on tree physiological processes on annual or finer time steps. They can also be used to test process-based ecophysiological models for the assumptions, hypotheses, and simplifications embedded within them. However, numerous physiological and biophysical processes influence the stable carbon (δ13C) and oxygen (δ18O) isotopes in tree rings, so the models must simplify how they represent some of these processes to be useful. Which simplifications are appropriate depends on the application to which the model is applied. Fortunately, water and carbon fluxes represented in process-based models often have strong isotopic effects that are recorded in tree-ring signals. In this chapter, we review the status of several tree-ring δ13C and δ18O models simulating processes for trees, stands, catchments, and ecosystems. This review is intended to highlight the structural differences among models with varied objectives and to provide examples of the valuable insights that can come from combining process modeling with tree-ring stable isotope data. We urge that simple stable isotope algorithms be added to any forest model with a process representation of photosynthesis and transpiration as a strict test of model structure and an effective means to constrain the models.
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Leavitt, Steven W., and John Roden. "Isotope Dendrochronology: Historical Perspective." In Stable Isotopes in Tree Rings, 3–20. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-92698-4_1.
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AbstractAlthough the fields of dendrochronology and light stable-isotope mass spectrometry emerged at different times in the first half of the 20th Century, their convergence with the earliest measurements of isotope composition of tree rings is now ca. 70 years old. Much of the early stable isotope analysis (including on wood) explored natural variation of isotopes in the environment, but those researchers making the measurements were already contemplating the role of the isotope composition of the source substrates (e.g., water and CO2), biochemical fractionation, and environment as contributors to final tree-ring isotope values. Growing interest in tree-ring isotopes was heavily motivated by paleoclimate or paleoatmosphere reconstruction, but this new field rapidly developed to generate greatly improved mechanistic understanding along with expanded applications to physiology, ecology, pollution, and more. This chapter primarily charts the historical progression in tree-ring C-H-O isotope studies over those seven decades, but it also identifies potential productive emerging and future directions.
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Belmecheri, Soumaya, William E. Wright, and Paul Szejner. "Sample Collection and Preparation for Annual and Intra-annual Tree-Ring Isotope Chronologies." In Stable Isotopes in Tree Rings, 103–34. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-92698-4_4.
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AbstractThis chapter provides guidance for conducting studies based on stable isotope measurements in tree rings to infer past and present climate variability and ecophysiology. Balancing theoretical perspectives of stable isotope variations recorded in tree rings, intended research applications (paleoclimate or ecophysiology) and resource limitations, this chapter describes key aspects of field sampling strategies and laboratory sample processing. It presents an overview of factors influencing variations and thus interpretations of carbon and oxygen isotopes, including juvenile/age effects, canopy status and stand characteristicsto inform sampling strategies that optimize a robust paleoenvironmental and physiological signal with statistically defined confidence limits. Fieldwork considerations include the selection of a study site and trees, field equipment, and sample requirements to recover sufficient material for isotopic measurements, and the desired environmental signal. Aspects of laboratory sample processing include choosing a sampling resolution (e.g. whole ring, earlywood/latewood, thin section, etc.), sample pooling within and between trees, and particle size requirements for chemical extraction and analytical repeatability. Finally, this chapter provides a case study highlighting the potential benefits and limitations of high-resolution sub-seasonal sampling.
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Belmecheri, Soumaya, William E. Wright, and Paul Szejner. "Sample Collection and Preparation for Annual and Intra-annual Tree-Ring Isotope Chronologies." In Stable Isotopes in Tree Rings, 103–34. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-92698-4_4.
Повний текст джерелаАнотація:
AbstractThis chapter provides guidance for conducting studies based on stable isotope measurements in tree rings to infer past and present climate variability and ecophysiology. Balancing theoretical perspectives of stable isotope variations recorded in tree rings, intended research applications (paleoclimate or ecophysiology) and resource limitations, this chapter describes key aspects of field sampling strategies and laboratory sample processing. It presents an overview of factors influencing variations and thus interpretations of carbon and oxygen isotopes, including juvenile/age effects, canopy status and stand characteristicsto inform sampling strategies that optimize a robust paleoenvironmental and physiological signal with statistically defined confidence limits. Fieldwork considerations include the selection of a study site and trees, field equipment, and sample requirements to recover sufficient material for isotopic measurements, and the desired environmental signal. Aspects of laboratory sample processing include choosing a sampling resolution (e.g. whole ring, earlywood/latewood, thin section, etc.), sample pooling within and between trees, and particle size requirements for chemical extraction and analytical repeatability. Finally, this chapter provides a case study highlighting the potential benefits and limitations of high-resolution sub-seasonal sampling.
Тези доповідей конференцій з теми "Os isotopes"
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Travis, J. C., T. B. Lucatorto, J. Wen, J. D. Fassett, and C. W. Clark. "Doppler-Free Resonance Ionization Mass Spectrometry of Beryllium." In Laser Applications to Chemical Analysis. Washington, D.C.: Optica Publishing Group, 1987. http://dx.doi.org/10.1364/laca.1987.tub2.
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As originally conceived, resonance ionization mass spectrometry (RIMS) combined the elemental selectivity of resonance ionization (1) with the isotopic selectivity of mass spectrometry to improve the accuracy and sensitivity of conventional mass spectrometry (2). For many applications, especially quantitation by isotope dilution (3) , it is important that no isotopic selectivity accompany the resonance ionization process. This condition is easily met for all but a few elements of the periodic table (4), since the great majority of optical isotope shifts are small with respect to typical dye laser bandwidths and Doppler-broadened linewidths in common atom reservoirs. However, another class of problem exists for which it is desirable to achieve isotopically selective resonance ionization. These applications involve the detection of extremely, rare stable or radioactive isotopes in the presence of the major isotopic species of an element. Miller et al. (5) have explored the optical isotopic selectivity of the isotopes of Lu using a RIMS spectrometer equipped with a high-resolution (single-mode) continuous-wave (cw) laser. Cannon et al. (6) have measured an optical selectivity (defined below) of 800 for isotopes of Ba, using a RIMS spectrometer with two cw lasers. We have proposed the use of pulsed, two-photon, Doppler-free resonance ionization to extend the capability of conventional mass spectrometers to measure isotope ratios in excess of 1012 (7). Initial experimental results using this approach, for the isotopes 9Be and 10Be, are reported here.
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Wunderlich, R. K., G. J. Wasserburg, I. D. Hutcheon, and G. A. Black. "Laser-induced mass selectivity in resonance ionization mass spectrometry of Os." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1991. http://dx.doi.org/10.1364/oam.1991.wp1.
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Measurements of isotope ratios by resonance ionization mass spectrometry depend critically on knowledge of isotopic-specific effects in the laser excitation-ionization process. Reports of odd-even isotope selectivity in RIMS studies of Mo, Sn,1 and Ti have led us to investigate isotope shifts in a RIMS study of Os. We identify three sources of laser-induced mass selectivity: (i) wavelength and bandwidth effects, (ii) selection rule and polarization effects, and (iii) dynamic effects.2 (i) In the presence of optical isotope shifts and hyperfine structure the finite laser bandwidth and reproducibility of wavelength setting produce isotope shifts as a result of the incomplete overlap of the laser spectrum with the absorption maxima of the Os isotopes and their HFS components.
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Pyrayev, A. N., and A. A. Maksimova. "ISOTOPIC COMPOSITION OF GROUNDWATER IN OIL AND GAS DEPOSITS IN THE CENTRAL PART OF THE TRANS-URAL MEGAMONOCLISE." In All-Russian Youth Scientific Conference with the Participation of Foreign Scientists Trofimuk Readings - 2021. Novosibirsk State University, 2021. http://dx.doi.org/10.25205/978-5-4437-1251-2-117-120.
Повний текст джерелаАнотація:
The article presents the first results of complex isotope-hydrogeochemical studies of reservoir waters of the Upper Jurassic deposits of the central regions of the Zaural megamonoclysis. It was shown that most waters have a narrow distribution of oxygen and hy-drogen isotopes (δD from 103,2 to –85,6 % and δ18O from –15,4 to –12,9 %). Some of them have pronounced excursions on the isotopic composition, which indicates a difference in their genesis: from condensate to mixed with ancient infiltrogenic. The isotopic composition of car-bon of water-dissolved carbon dioxide (δ13СDIC from –41,6 to –16,3 %) indicates its biogenic origin and the possibility of interstratal flows from overlying horizons.
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Miller, C. M., R. Engleman, and R. A. Keller. "Resonance ionization mass spectrometry for high-resolution mass-resolved spectra of rare isotopes." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1985. http://dx.doi.org/10.1364/oam.1985.tha2.
Повний текст джерелаАнотація:
Previous isotope ratio measurements using resonance ionization mass spectrometry (RIMS) have used element selective photoionization with isotope ratios measured by dispersion of ions in a mass spectrometer. To increase the accuracy and dynamic range of isotope ratio measurements, it may be necessary to use isotopically selective ionization. To be successful in this task it is necessary to know isotope shifts and hyperfine structures of the optical transition(s) used for the isotopes of interest. We are particularly interested in rare and sometimes highly radioactive elements for which this information is not readily available. We demonstrate that the sensitivity and mass selectivity of the RIMS technique itself can be used to obtain the needed spectra. With this goal in mind, RIMS was used to acquire high-resolution optical spectra of rare isotopes. To demonstrate the potential of this technique, hyperfine spectra of the 2 D 3 / 2 0 ← 2 D 3 / 2 lutetium transition at 22,125 cm–1 are presented for 176Lu, 175Lu, 174Lu, and 173Lu. The latter two are rare isotopes with half-lives of 3.3 and 1.4 yr whose optical spectroscopy has not previously been explored. Sensitivity is documented by the fact that the total amount of these rare isotopes in our sample was 2 × 10–10 g and 3 × 10–11 g. Analysis of the spectra confirms that the spin of 174Lu is unity and yields values for the hyperfine constants and isotope shifts of these nuclei.
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Lu, Feng Hu. "Using Isotope Technology to Identify Oil and Gas Reservoir Sweet Spots." In SPE Reservoir Characterisation and Simulation Conference and Exhibition. SPE, 2023. http://dx.doi.org/10.2118/212642-ms.
Повний текст джерелаАнотація:
Abstract Porosity and permeability of rocks are crucial parameters utilized to assess the quality of oil and gas reservoirs. Diagenesis in carbonate reservoirs commonly results in dissolution, and creates secondary porosity and permeability. At the same time, geochemical records (e.g., isotopes and elements) in the carbonate rocks are diagenetically altered. This study is to utilize the isotope technology to evaluate diagenesis and its impact on oil and gas reservoirs. Micro-samples were collected from marine carbonate rocks in a studied reservoir for carbon and oxygen isotope analyses, plus analyses of Sr isotopes and element concentrations. The analytical results show outstanding negative shifts of oxygen isotopes in some intervals, whereas carbon and strontium isotopes have a minor or little change. These intervals also contain lower element contents including strontium. It is believed that these intervals experienced diagenetic dissolution with abundant secondary porosity, and are the best potential for oil and gas reservoirs. Petrographic study indicates minor cements but higher porosity developed within these intervals. This is confirmed by high porosity measured within these intervals by using other methods including gas injection and well logging. Furthermore, the degrees of water-rock interaction were quantitively assessed by modeling covariations of isotope pairs, which can help evaluate the quality of reservoirs relating to the intensity of diagenesis. Intensive diagenesis with a high water-rock ratio particularly in a closed system may result in additional cementation, alteration of most geochemical parameters, and also reduce porosity and permeability. Thus, the isotope technology can be utilized as an effective method to assess reservoir potential and determine reservoir sweet spots. Note that carbonate cementation and recrystallization commonly occur during diagenesis, and commonly show negative oxygen isotope values. If sampling happens to contain a certain amount of cements and recrystallized carbonate minerals, the analytical results will show lower oxygen isotopes and trace elements than their primary values in the studied marine carbonates. Petrographic study was conducted to help micro-sampling, and verify that cements were not collected in the studied carbonate rocks for isotope analysis. The implementation of this study is that the isotope results obtained from one studied well can be applied in the whole field or/and the region, as diagenesis rarely occurs only around one well. This will save cost for repeatedly measurements from different wells and fields by using other methods.
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Eerkens, Jeff W., Jay F. Kunze, and Leonard J. Bond. "Laser Isotope Enrichment for Medical and Industrial Applications." In 14th International Conference on Nuclear Engineering. ASMEDC, 2006. http://dx.doi.org/10.1115/icone14-89767.
Повний текст джерелаАнотація:
Use of lasers for isotope separation has been considered for many decades. None of the proposed methods have attained sufficient proof of principal status to be economically attractive to pursue commercially. Some of the authors have succeeded in separating sulfur isotopes using a rather new and different method, known as condensation repression. In this scheme, a gas of the selected isotopes for enrichment is irradiated with a laser at a particular wavelength that would excite only one of the isotopes. The entire gas is subjected to low temperatures sufficient to cause condensation on a cold surface or coagulation in the gas. Those molecules in the gas that the laser excited are not as likely to condense or dimerize (coagulate into a double molecule, called a dimer) as unexcited molecules. Hence in cold-wall condensation, gas drawn out of the system is enriched in the isotope that was laser-excited. We have evaluated the relative energy required in this process if applied on a commercial scale. We estimate the energy required for laser isotope enrichment is about 30% of that required in centrifuge separations, and 2% of that required by use of “calutrons”.
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Jia Yi, Xu, Ma Xu Bo, Shen Jing Wen, Liu Jia Yi, and Chen Yi Xue. "A New Method to Evaluate the Correlation Coefficients Between Nuclides in Uncertainty and Sensitivity Analysis." In 2017 25th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/icone25-66777.
Повний текст джерелаАнотація:
Uncertainty and sensitivity analysis is an essential component of nuclear engineering calculations. Uncertainties in the cross-section input data directly affect uncertainties in the results. The covariance values between different types of cross-sections are considered in the NJOY covariance library. However, the correlation coefficient between isotopes can depend on the specific problem. The correlation coefficient between 235U and 238U in a pressurized water reactor (PWR) might be different from that in a fast reactor. In this study, a new Monte Carlo-based method is proposed for calculating this effect. The correlation coefficients between different isotopes are calculated using a problem-dependent fraction parameter. The correlation coefficients between the capture cross-sections of 235U, 238U, 239Pu, and 241Pu are calculated. The same method can be extended to other reaction types. The correlation coefficients as a function of the isotopic atomic density uncertainty and the average one-group microscopic cross-section uncertainty are also studied. It is shown that the correlation coefficients vary very little with the uncertainty in the average one-group microscopic cross-section. The correlation coefficient of an isotope pair changes slightly over the course of a cycle because of atomic density and microscopic cross-section changes.
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Fearey, B. L., and B. M. Tissue. "High-resolution spectroscopy of Th and Pa isotopes." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1992. http://dx.doi.org/10.1364/oam.1992.mkk7.
Повний текст джерелаАнотація:
Doppler-free spectroscopy has been performed on thorium and protactinium isotopes to gain a detailed understanding of the underlying physics of spectral features. Characterizing phenomena such as Lamb dips and optical pumping are important in understanding and optimizing resonance ionization mass spectrometry (RIMS) analysis. Measurement of these isotopes by RIMS is used in U-series disequilibrium dating of geological samples of the last 400,000 years. Isotope shifts and hyperfine structure of 232Th, 230Th, 229Th, 233Pa, and 231Pa are reported for several transitions. The Doppler-free spectra of Th showed an interesting effect, which was strongly dependent on laser power, in which a narrow peak replaced the usual Lamb dip. These results and a detailed analysis will be presented and discussed.
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Dzhimak, Stepan S., Anna Elkina, and Alexandr A. Basov. "MECHANISMS OF FRACTIONATION OF STABLE ISOTOPES IN LIVING SYSTEMS." In NEW TECHNOLOGIES IN MEDICINE, BIOLOGY, PHARMACOLOGY AND ECOLOGY. Institute of information technology, 2021. http://dx.doi.org/10.47501/978-5-6044060-1-4.17.
Повний текст джерелаАнотація:
Some physical laws are considered that provide stable fractionation of isotopes, leading to the accumulation of certain isotopic forms in the intracellular and intercellular space with the manifestation of these effects at various levels of the organism. It is suggested that for a more complete understanding of the above processes, it is necessary to study the mechanism of exchange interaction between particles with integer spin (bosons) and half-integer spin (fermions).
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Kautzsch, T., W. B. Walters, and K. L. Kratz. "Laser isotope and isomer separation of neutron-rich Ag-isotopes." In The second international workshop on nuclear fission and fission-product spectroscopy. AIP, 1998. http://dx.doi.org/10.1063/1.56740.
Повний текст джерелаЗвіти організацій з теми "Os isotopes"
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Fitzsimmons, Jonathan. Fishing for isotopes in the Brookhaven Lab Isotope Producer (BLIP) cooling water. Office of Scientific and Technical Information (OSTI), April 2016. http://dx.doi.org/10.2172/1340357.
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Nielsen, D. L. Transportation of medical isotopes. Office of Scientific and Technical Information (OSTI), November 1997. http://dx.doi.org/10.2172/362356.
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Author, Not Given. Isotopes: Products and services. Office of Scientific and Technical Information (OSTI), March 1989. http://dx.doi.org/10.2172/5992318.
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McIntyre, Justin I., Ted W. Bowyer, James C. Hayes, Tom R. Heimbigner, Scott J. Morris, Mark E. Panisko, W. K. Pitts, Sharon L. Pratt, Paul L. Reeder, and Charles W. Thomas. Generation of Radixenon Isotopes. Office of Scientific and Technical Information (OSTI), June 2003. http://dx.doi.org/10.2172/15020775.
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Brown, D., and J. Pruet. Updated Evaluations for Americium Isotopes. Office of Scientific and Technical Information (OSTI), September 2005. http://dx.doi.org/10.2172/887268.
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Stehney, A. F., and H. F. Lucas. Thorium isotopes in human tissues. Office of Scientific and Technical Information (OSTI), December 1991. http://dx.doi.org/10.2172/10173422.
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Jacques, I. J., A. J. Anderson, and S. G. Nielsen. The geochemistry of thallium and its isotopes in rare-element pegmatites. Natural Resources Canada/CMSS/Information Management, 2021. http://dx.doi.org/10.4095/328983.
Повний текст джерелаАнотація:
The Tl isotopic and trace element composition of K-feldspar, mica, pollucite and pyrite from 13 niobium-yttrium-fluorine (NYF)-type and 14 lithium-cesium-tantalum (LCT)-type rare-element pegmatites was investigated. In general, the epsilon-205Tl values for K-feldspar in NYF- and LCT-type pegmatites increases with increasing magmatic fractionation. Both NYF and LCT pegmatites display a wide range in epsilon-205Tl (-4.25 to 9.41), which complicates attempts to characterize source reservoirs. We suggest 205Tl-enrichment during pegmatite crystallization occurs as Tl partitions between the residual melt and a coexisting aqueous fluid or flux-rich silicate liquid. Preferential association of 205Tl with Cl in the immiscible aqueous fluid may influence the isotopic character of the growing pegmatite minerals. Subsolidus alteration of K-feldspar by aqueous fluids, as indicated by the redistribution of Cs in K-feldspar, resulted in epsilon-205Tl values below the crustal average (-2.0 epsilon-205Tl). Such low epsilon-205Tl values in K-feldspar is attributed to preferential removal and transport of 205Tl by Cl-bearing fluids during dissolution and reprecipitation. The combination of thallium isotope and trace element data may be used to examine late-stage processes related to rare-element mineralization in some pegmatites. High epsilon-205Tl and Ga in late-stage muscovite appears to be a favorable indicator of rare-element enrichment LCT pegmatites and may be a useful exploration vector.
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Pruet, J., D. McNabb, and W. Ormand. Cross Section Evaluations for Arsenic Isotopes. Office of Scientific and Technical Information (OSTI), March 2005. http://dx.doi.org/10.2172/15015183.
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Papenbrock, Thomas. Final Report "Structure of Rare Isotopes". Office of Scientific and Technical Information (OSTI), May 2012. http://dx.doi.org/10.2172/1039704.
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Clegg, Samuel M., Kristy Lynne Nowak-Lovato, Julianna E. Fessenden-Rahn, Stephen J. Obrey, and Robert P. Currier. Remote Detection of NO2 Stable Isotopes. Office of Scientific and Technical Information (OSTI), October 2012. http://dx.doi.org/10.2172/1053541.
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