Дисертації з теми "Carbon isotope ratios"
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Lockheart, Matthew James. "Isotope compositions and distributions of individual compounds as indicators for environmental conditions : comparisons between contemporary and Clarkia fossil leaves." Thesis, University of Bristol, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389098.
Повний текст джерелаVaiglova, 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 джерелаHuset, Regina Anne. "Methyl halides : concentrations, fluxes and stable carbon isotope ratios measured in the atmosphere, coastal waters, and soils /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/11576.
Повний текст джерелаHörner, Gerald, Steffen Lau, and Hans-Gerd Löhmannsröben. "NIR-diode laser spectroscopy for isotope-selective sensing of soil-respired carbon dioxide." Universität Potsdam, 2004. http://opus.kobv.de/ubp/volltexte/2006/1014/.
Повний текст джерелаAn, Yan. "The Potential of Bulk and Amino-Acid Specific Isotope Ratio Mass Spectrometry of Human Hair in Forensic and Clinical Applications." Ohio University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1363701887.
Повний текст джерелаTrudell, Steven A. "Patterns of nitrogen and carbon stable isotope ratios in macrofungi, plants, and soils from two old-growth conifer forests, Olympic National Park, Washington, USA /." Thesis, Connect to this title online; UW restricted, 2004. http://hdl.handle.net/1773/5572.
Повний текст джерелаBlaszczyck, D., Julia Beaumont, A. Krzyszowski, D. Poliński, and A. Drozd-Lipińska. "Social status and diet. Reconstruction of diet of individuals buried in some early medieval chamber graves from Poland by carbon and nitrogen stable isotopes analysis." Science Direct, 2021. http://hdl.handle.net/10454/18572.
Повний текст джерелаThe study presents results of the investigations of diet based on carbon and nitrogen stable isotope ratios (δ13C and δ15N) of the bone collagen of individuals buried in medieval elite chamber graves from the territory of the state of the first Piasts, Poland (the second half of the 10th and the first half of the 11th century). The aim of the research was to determine the diet of individuals buried in such funerary structures, to compare this with commoners buried in ordinary graves, and investigate any sex-related patterns. Rib bone samples were taken from individuals buried in chamber graves at Bodzia, Dziekanowice, Pień and Sowinki. Results indicate that the elite male diet was based on C3 plants with possible contribution of some C4 plants (millet) and substantial consumption of animal proteins including fish. The bone collagen δ13C and δ15N of male chamber burials suggested consumption of higher trophic level foodstuffs (meat and fish) whilst the female diet, and that of the juveniles, was similar to the commoners in the rest of the population.
Gagen, M. H. "The response of pine trees to climate in the southern French Alps and the palaeoclimatic potential of stable carbon isotope ratios from treerings." Thesis, Swansea University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.637018.
Повний текст джерелаJohnson, Laurie. "Assessing the effect of feather wear on carbon and nitrogen stable isotope ratios, and the use of stable isotopes to determine predator diets in the Namibian Islands marine protected area." Master's thesis, Faculty of Science, 2019. http://hdl.handle.net/11427/31248.
Повний текст джерелаXia, Yang. "Impact of varying NH₄⁺˸NO₃⁻ ratios in nutrient solution on C-isotope composition of leaf- and root-respired CO₂ and putative respiratory substrates in C₃ plants." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS222.
Повний текст джерелаC-isotope composition of leaf- and root-respired CO₂ in the dark and that of putative respiratory substrates including soluble sugars and organic acids (malate and citrate), PEPc activity, as well as leaf gas exchanges were determined on bean (Phaseolus vulgaris L.) and spinach (Spinacia oleracea L.) plants grown in sand with varying ratios of NH₄⁺: NO₃⁻ in supplied N. Leaf-respired CO₂ was ¹³C enriched under NO₃⁻ nutrition and became progressively ¹³C depleted with increasing amount of NH₄⁺ in supplied N, while C-isotope composition of root-respired CO₂ remained unchanged across N-type gradient. We suggested that a higher amount of ¹³C enriched C-pools fixed by PEPc through anaplerotic pathway contributed to respired CO₂ in leaves under NO₃⁻ nutrition. However, a similar effect in roots expected under NH4+ nutrition was masked because of a rather ¹³C depleted C source (respired CO₂) refixation by PEPc. Unexpectedly, the changes in C-isotope composition of individual metabolites and their amounts as well as PEPc activity exhibited different patterns between the two species. Double labelling experiments (¹³C and ¹⁵N) are needed for better understanding the impact of metabolic plasticity of TCA on isotopic gap between malate and citrate and on C-isotope composition of respired CO₂ in different species under varying N-type nutrition
Sholto-Douglas, A. D. "The use of stable isotope ratios of carbon and nitrogen to elucidate pelagic marine foodwebs of the Benguela and Agulhas Bank regions of South Africa." Master's thesis, University of Cape Town, 1992. http://hdl.handle.net/11427/17370.
Повний текст джерелаIsotope assessments of foodweb relationships amongst pelagic organisms may be influenced by their lipid content, since lipids are more depleted in ¹³C than other biochemical compounds. This is particularly important for plankton which show a greater decrease in δ¹³C caused by the failure to remove lipids during sample preparation, than the muscle tissue of pelagic fish species. Lipid removal is important for those fish species whose lipid content and magnitude of diet-consumer fractionation are simultaneously related to their size. The period required for pelagic fish to isotopically reflect a new diet is slow, of the order of months and years, and may depend on the diet and the magnitude of isotopic change displayed. It is likely that this rate decreases as the fish approach isotopic equilibrium with the new food source.
Beukes, Brandon. "Examining intra- and interspecific variability in the diet and carbon and nitrogen stable isotope ratios of kingklip and monkfish caught off the West and South coasts of South Africa." University of Western Cape, 2020. http://hdl.handle.net/11394/8234.
Повний текст джерелаKingklip (Genypterus capensis) and monkfish (Lophius vomerinus) and are ecologically and economically important demersal fish species that are found along both the eastern and western parts of southern Africa’s coastline. Despite their commercial value, limited information exists focusing on the trophic ecology of these two species. This is the first study to make use of both stomach content analysis and stable isotope analysis to directly compare and examine the trophic ecology of G. capensis and L. vomerinus off the West and South coast of South Africa.
2022
Parkins, Colleen Ann. "Stable carbon and nitrogen isotope ratios in the shallow-water cape hake, merluccius capensis (castelnau) as indicators of trophic position and diet on the west and south coasts of South Africa." Master's thesis, University of Cape Town, 1993. http://hdl.handle.net/11427/6156.
Повний текст джерела13C/12C and 15N/14N were used to indicate the trophic levels of the shallow-water Cape hake, Merluccius capensis (Castelnau) at three sites on the west coast of South Africa, and five sites on the south coast. Gut content analyses show only the very recent diet of hake, therefore stable carbon and nitrogen isotope ratios were used to show the longer-term diet, integrated over the turnover time of the muscle tissue and bone collagen analysed. 13C/12C is 1-2%₀ higher in the tissues of a consumer than its diet (DeNiro and Epstein 1978), the difference in 15N/14N between a consumer and its food being 3-4%₀ (DeNiro and Epstein 1981). Both 13C/12C and 15N/14N indicate trophic enrichment between hake muscle tissue and bone collagen, and the gut contents and prey, and show that small and large hake feed at different trophic levels, large hake tissues being slightly heavier in 13C than small hake tissues, and containing 2-4%₀ more 15N than muscle tissue and bone collagen, and the gut contents and prey, and show that small and large hake feed at different trophic levels, large hake tissues being slightly heavier in 13C than small hake tissues, and containing 2-4%₀ and more 15N than muscle tissue and bone collagen of small hake.
Traffichini, Andrea M. "Reconstruction of Northeastern Pacific Ocean Holocene Production Using Marine Mammal Archaeofauna." Thesis, NSUWorks, 2019. https://nsuworks.nova.edu/occ_stuetd/513.
Повний текст джерелаHowcroft, Rachel. "Weaned Upon A Time : Studies of the Infant Diet in Prehistory." Doctoral thesis, Stockholms universitet, Institutionen för arkeologi och antikens kultur, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-88237.
Повний текст джерелаAt the time of doctoral defense the following papers were unpublished and had a status as follows: Paper 1: Manuscript; Paper 4: Accepted; Paper 5: Forthcoming 2014
Lactase Persistence and the early Cultural History of Europe (LeCHE)
Fomes, Charles William. "Development of novel oxidation catalysts for carbon isotope ratio analysis." Thesis, Open University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343742.
Повний текст джерелаKim, Moon Koo. "Stable carbon isotope ratio of polycyclic aromatic hydrocarbons (PAHs) in the environment: validation of isolation and stable carbon isotope analysis methods." Diss., Texas A&M University, 2004. http://hdl.handle.net/1969.1/1099.
Повний текст джерелаCarr, R. H. "High sensitivity stable carbon isotope ratio mass spectrometry : instrument development application." Thesis, University of Cambridge, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303835.
Повний текст джерелаMiddleton, Gideon Paul Grevatt. "Variations in the carbon isotope ratio of phytoplankton and dissolved inorganic carbon in the marine environment." Thesis, Bangor University, 1997. https://research.bangor.ac.uk/portal/en/theses/variations-in-the-carbon-isotope-ratio-of-phytoplankton-and-dissolved-inorganic-carbon-in-the-marine-environment(b0e1349d-7de6-46f5-ab2a-cc4b939b8b0c).html.
Повний текст джерелаKannath, Arun. "Precision measurement of carbon isotope ratio in exhaled breath for the detection of Helicobacter pylori." Thesis, University of Southampton, 2009. https://eprints.soton.ac.uk/68791/.
Повний текст джерелаMuccio, Zeland. "Isotope ratio mass spectrometry a rapidly developing tool for forensic samples /." Ohio : Ohio University, 2010. http://www.ohiolink.edu/etd/view.cgi?ohiou1263488205.
Повний текст джерелаSILVA, GILSON CRUZ DA. "SOURCE APPOINTMENT OF FOSSIL FUELS AND BIOFUELS USING CARBON, HYDROGEN AND OXIGEN ISOTOPIC RATIOS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2015. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=29646@1.
Повний текст джерелаCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE SUPORTE À PÓS-GRADUAÇÃO DE INSTS. DE ENSINO
A frota veicular brasileira utiliza largamente combustíveis fósseis, como a gasolina, e biocombustíveis, como o bioetanol, este último utilizado in natura, na forma hidratada, ou como aditivo para a gasolina, na forma anidra. Em caso de vazamento destes combustíveis leves para o meio ambiente, a correlação entre contaminantes e fontes suspeitas aplicando técnicas tradicionais, como a Cromatografia Gasosa acoplada à Espectrometria de Massas (GC-MS - Gas Chromatography coupled to Mass Spectrometry) é extremamente difícil, pois gasolinas não possuem biomarcadores e apresentam distribuições de hidrocarbonetos semelhantes, enquanto a diferenciação inequívoca do etanol é inviável. Uma alternativa analítica recente é a Análise de Isótopos Estáveis de Compostos Específicos (CSIA - Compound-specific stable isotope analysis) por meio de Espectrometria de Massas de Razão Isotópica em Fluxo Contínuo (CF-IRMS - Continuous Flow Isotope Ratio Mass Spectrometry). Neste trabalho, uma metodologia de análise isotópica aplicável à gasolina foi implementada utilizando também a extração em Headspace (HS-CF-IRMS). A introdução de amostras por Micro Extração em Fase Sólida (SPME - Solid Phase Micro Extraction), como alternativa ao Headspace, também foi avaliada, apresentando, no entanto, problemas técnicos que restringiram seu uso apenas aos padrões de BTEX, inviabilizando sua aplicação em amostras de gasolina nas condições testadas. Foram analisadas as razões isotópicas de hidrogênio (delta elevado a 2 H) de tolueno, etilbenzeno e xilenos de 38 amostras de gasolina coletadas em 12 refinarias brasileiras ao longo de várias campanhas de amostragem, visando avaliar a existência de assinaturas isotópicas específicas para cada refinaria pesquisada. Os resultados foram avaliados estatisticamente utilizando Análise de Variância (ANOVA), na qual foram encontrados grupos de dados estatisticamente homogêneos. A representação e análise gráfica tridimensional destes grupos de dados permitiu identificar seis refinarias com razões isotópicas específicas, assim como dois conjuntos de refinarias agrupadas por similaridade de assinaturas isotópicas na maioria dos gráficos estudados. No entanto, devido a valores discrepantes entre campanhas distintas para algumas refinarias, os resultados preliminares obtidos neste estudo são válidos somente para as campanhas não excluídas no tratamento estatístico, não podendo, portanto, ser entendidos como uma regra geral. Com relação ao etanol, marcadores isotópicos foram utilizados e testados como ferramenta para identificação de sua origem geográfica. Neste caso, foram avaliadas as razões isotópicas de carbono (delta elevado a 13 C) e hidrogênio (elevado a 2 H) do biocombustível produzido em quatro usinas localizadas em áreas de cultivo dos estados do Amazonas (Norte), Mato Grosso (Centro-Oeste), São Paulo (Sudeste) e Rio Grande do Sul (Sul), bem como os valores de delta13C da cana-de-açúcar coletada nos respectivos canaviais. A técnica empregada foi CF-IRMS. Também foram determinados os perfis isotópicos de oxigênio (delta elevado a 18 O) e hidrogênio em água da planta, do solo de cultivo, da precipitação pluviométrica e de corpos d água associados aos canaviais das respectivas usinas, através da técnica de Espectroscopia de Infravermelho de Razão Isotópica (IRIS – Isotope Ratio Infrared Spectroscopy). O etanol apresentou variações sazonais de delta2H similares às observadas para a água da planta, ressaltando a influência do ciclo hidrológico na sua razão isotópica. Foi constatado que a influência substancial e complexa do ciclo hidrológico sobre delta elevado a 2 H, aliada à pequena variação de delta elevado a 13 C, dificulta o uso destes isótopos como marcadores de origem do etanol.
Brazilian vehicle fleet makes wide use of fossil fuels and biofuels such as gasoline and bioethanol, the latter used neat, hydrated, or as gasoline additive, anhydrous. In case of leakage of such light fuels to the environment, correlation between contaminants and suspicious sources applying traditional techniques such as Gas Chromatography coupled to Mass Spectrometry (GC-MS) is extremely difficult, since gasoline does not have biomarkers and presents similar hydrocarbons distributions, while unambiguous differentiation of ethanol is unfeasible. A recent analytical alternative is the Compound-Specific Stable Isotope Analysis (CSIA) by Continuous Flow Isotope Ratio Mass Spectrometry (CF-IRMS). In this work, a methodology for isotopic analysis suitable to gasoline was implemented using also headspace extraction (HS-CF-IRMS). Sample introduction using Solid Phase Micro-Extraction (SPME) as an alternative to Headspace was also evaluated, presenting, however, technical problems which restricted its use only to BTEX standards, preventing its application in gasoline samples under the tested conditions. Analyses of hydrogen isotopic ratios (delta 2 H) for toluene, ethylbenzene and xylenes present in the composition of 38 gasoline samples collected in 12 Brazilian refineries were performed along several sampling campaigns, aiming at the assessment of the existence of specific isotopic signatures for each refinery studed. Results obtained were statistically evaluated using Analysis of Variance (ANOVA), yielding statistically homogeneous groups of data. Graphical representation analysis in 3D of these data sets allowed the identification of six refineries with specific isotopic ratios, as well as two sets grouped by similarity of their isotopic ratios in most of the studied plots. However, due to inconsistent values between different campaigns for some refineries, the preliminary results obtained in this study are valid only for the campaigns not excluded in the statistical treatment, therefore they cannot be understood as a general rule. Regarding to ethanol, isotopic markers were used and tested as a tool for identification of its geographical origin. In this case carbon and hydrogen isotopic ratios (delta 13 C and delta 2 H) were evaluated in the biofuel produced in four sugarcane mills located in crop areas from the states of Amazonas (North), Mato Grosso (Center-West), São Paulo (Southeast) and Rio Grande do Sul (South), as well as delta 13 C values in plants collected in respective sugarcane fields. The technique used was CF-IRMS. Also, oxygen (delta 18 O) and hydrogen isotopic patterns were determined in plant-water, soil-water, rainwater, and water from reservoirs and some rivers associated to each sugarcane mill, through Isotope Ratio Infrared Spectroscopy (IRIS). Ethanol showed similar seasonal variation of delta 2 H as those observed for plant-water, highlighting the influence of hydrological cycle on the isotopic fingerprint of the alcohol. It was found that the substantial and complex influence of the hydrological cycle on delta 2 H and the small variations on delta 13 C constrain the use of isotopes as tracers for ethanol origin.
Milam, Stefanie Nicole. "Following Carbon's Evolutionary Path: From Nucleosynthesis to the Solar System." Diss., The University of Arizona, 2007. http://hdl.handle.net/10150/194067.
Повний текст джерелаFavaro, Yvette Leeann. "Molecular characterization and carbon isotope ratio analysis of marine hydrocarbons in sediments from Trinity Bay, Newfoundland." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ34180.pdf.
Повний текст джерелаJuranek, Lauren Wray. "Assessment of Pacific Ocean carbon production and export using measurements of dissolved oxygen isotopes and oxygen/argon gas ratios /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/11055.
Повний текст джерелаHörner, Gerald, Steffen Lau, Zoltan Kantor, and Hans-Gerd Löhmannsröben. "Isotope selective analysis of CO2 with tunable diode laser (TDL) spectroscopy in the NIR." Universität Potsdam, 2004. http://opus.kobv.de/ubp/volltexte/2006/1016/.
Повний текст джерелаSun, Chenggong. "Source apportionment of polycyclic aromatic hydrocarbons (PAHs) in the environment using gas chromatography : stable carbon isotope ratio mass spectrometry." Thesis, University of Strathclyde, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248363.
Повний текст джерелаAnderson, Kelly C. "Stable carbon and nitrogen isotope analyses of subfossil rats from Liang Bua (Flores, Indonesia)." Master's thesis, University of Central Florida, 2011. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4837.
Повний текст джерелаID: 030423461; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (M.A.)--University of Central Florida, 2011.; Includes bibliographical references.
M.A.
Masters
Anthropology
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NAKAMURA, Toshio, Hiroki KONDO, 俊夫 中村 та 宏樹 近藤. "加速器質量分析計を用いた鉄製遺物の14C年代測定に関する基礎研究". 名古屋大学年代測定資料研究センター, 2012. http://hdl.handle.net/2237/18163.
Повний текст джерелаPietraszek-Mattner, Sarah R. "Characterizing progression of aerobic degradation of Paleozoic petroleums in Indiana soils using molecular ratios and carbon isotopic signatures." [Bloomington, Ind.] : Indiana University, 2004. http://wwwlib.umi.com/dissertations/fullcit/3162258.
Повний текст джерелаTitle from PDF t.p. (viewed Dec. 1, 2008). Source: Dissertation Abstracts International, Volume: 66-01, Section: B, page: 0166. Chair: Lisa M. Pratt.
Ohta, Tomoko, Toshio Nakamura, 友子 太田 та 俊夫 中村. "グラファイト生成と炭素同位体比変動 : 鉄触媒とサルフィックス処理の効果". 名古屋大学年代測定資料研究センター, 2011. http://hdl.handle.net/2237/16536.
Повний текст джерелаUpsdell, Brynn. "The carbon and nitrogen composition of suspended particulate matter in Lake Erie, selected tributaries, and its outflow." Thesis, University of Waterloo, 2005. http://hdl.handle.net/10012/1219.
Повний текст джерелаLloyd, Davidson A. "Effects of rhizosphere priming and microbial functions on soil carbon turnover." Thesis, Cranfield University, 2015. http://dspace.lib.cranfield.ac.uk/handle/1826/9278.
Повний текст джерелаRoden, John S., James A. Johnstone, and Todd E. Dawson. "Regional And Watershed-Scale Coherence In The Stable-Oxygen and Carbon Isotope Ratio Time Series in Tree Rings Of Coast Redwood (Sequoia Sempervirens)." Tree-Ring Society, 2011. http://hdl.handle.net/10150/622643.
Повний текст джерелаMablouké, Cécile. "Étude des ratios isotopiques du carbone et de l'azote de la matière organique particulaire et des muscles de poissons d'intérêt commercial d'écosystèmes côtiers tropicaux du sud-ouest de l'océan Indien : contribution à l'étude de leur fonctionnement." Thesis, La Réunion, 2013. http://www.theses.fr/2013LARE0017/document.
Повний текст джерелаThe aim of this thesis was to study the feeding habits of coastal fish species of commercial interest andto use stable isotopes of carbon (δ13C) and nitrogen (δ15N) to investigate the trophic niches of fish and their use of coastal habitats in the south-west Indian Ocean. In the Bay of La Possession, the species among the most abundant around the artificial reefs immersed in 2003 (Luljanus kasmira, Priacanthus hamrur and Selar crumenophthalmus) feed essentially on pelagic prey and partition their trophic niche to limit interspecific competition. There was also a positive correlation between fish size and muscle δ15N values due to fish larvae contributing more to the diet of fish with age. The stable isotopie composition of the particulate organic matter (POM) was measured at the microscale (< 10 km) in the Bay of La Possession, the mesoscale (10's of km) around Reunion Island and, for the fish muscles, at the macroscale 100’s of km) along the Mascarene plateau and the Mozambique channel. At microscale, POM δ15N values do not show any spatial variability; at mesoscale, POM is 15N-enriched in the south-west of Reunion Island; at macroscale, fish muscles are gradually 15N-enriched towards the north. At microscale, POM shows a 13C-enrichment on the shallowest station; at mesoscale, stations on the east coast of the island are 13C-enriched compared to the west; at macroscale, POMδ13C values are not significantly correlated with latitude. Thus, the stable isotopes of carbon do not seem to be appropriate for the study of fish coastal habitat use at the meso- and macroscale, and the stable isotopes of nitrogen represent a better indicator of fish habitat use at the macroscale
Aboglila, Salem Abdulghni-O. "Organic and isotopic geochemistry of source-rocks and crude oils from the East Sirte Basin (Libya)." Thesis, Curtin University, 2010. http://hdl.handle.net/20.500.11937/2118.
Повний текст джерелаKöten, Muharrem [Verfasser]. "An improved efficiency model for ACE-SWICS : determination of the carbon isotopic ratio 13C, 12C in the solar wind from ACE-SWICS measurements / Muharrem Köten." Kiel : Universitätsbibliothek Kiel, 2009. http://d-nb.info/1019812788/34.
Повний текст джерелаAlves, Marina Cabral. "Composição e acumulação da matéria orgânica (C, N, ligninas) nos sedimentos do sistema lagunar Mundaú – Manguaba, AL – Brasil." Niterói, 2017. https://app.uff.br/riuff/handle/1/3053.
Повний текст джерелаMade available in DSpace on 2017-03-14T18:31:18Z (GMT). No. of bitstreams: 1 Dissertação_MarinaAlves.pdf: 2711910 bytes, checksum: 2be4e3e9354ac9d7fcc36ea36bfd6cee (MD5)
Universidade Federal Fluminense. Instituto de Química. Programa de Pós-Graduação em Geociências- Geoquímica, Niterói, RJ
O Complexo Estuarino-Lagunar Mundaú-Manguaba (CELMM), situado no litoral nordeste do Brasil, vem sofrendo um processo contínuo de degradação ambiental, relacionado principalmente aos efluentes da agroindústria canavieira e ao crescimento urbano desordenado. Traçadores geoquímicos têm sido uma eficiente ferramenta na determinação da origem da matéria orgânica em sedimentos, se alóctone ou autóctone, podendo ser utilizados para identificar possíveis fontes de poluição produzidas por atividades antrópicas, bem como mudanças naturais no ambiente. Nesse contexto, esse trabalho teve como objetivo identificar a origem, transformação e acumulação recente da matéria orgânica nos sedimentos do CELMM. Para tal, cinco testemunhos, dois representando cada laguna, e um fluvial (Rio Mundaú), foram analisados quanto à distribuição vertical dos teores de argila, silte e areia, de carbono orgânico, da razão C/N, do 13C e de ligninas. A distribuição dos parâmetros analisados mostrou que a matéria orgânica sedimentar das lagunas tem origem predominantemente da sua própria produção primária fitoplanctônica. No entanto, a presença de ligninas, mesmo em baixas concentrações, indica a presença de material vegetal alóctone. No Rio Mundaú verificou-se a presença de material proveniente de angiospermas lenhosas, enquanto nas lagunas há grande mistura de angiospermas lenhosas e não lenhosas, sem um padrão claro de distribuição ao longo dos perfis. As razões (Ad/Al)v demonstraram que as ligninas encontradas possuem certo grau de degradação, contribuindo para uma possível redução na concentração total das mesmas, além de alterações nas razões S/V e C/V. A aplicação do índice LPVI (Lignin-Phenol Vegetation Index) para os lignino-fenóis permitiu obter maior clareza a cerca da evolução das fontes de material terrestre para o sistema, de forma que ficou evidente a transição de angiospermas lenhosas, vegetação anteriormente natural na bacia de drenagem, para angiospermas não lenhosas, a partir da expansão da atividade canavieira na região. Além disso, os resultados de acumulação de matéria orgânica nos sedimentos das lagunas demonstram um aumento de produtividade nas camadas mais recentes, como provável conseqüência dos efeitos da expansão agrícola e urbana no CELMM.
The Mundaú-Manguaba Estuarine-Lagoon System (MMELS), located in northeastern Brazil, has been undergoing a continuous process of environmental degradation, mainly related to the input of effluents from the sugar-cane industry and uncontrolled demographic expansion. Geochemical tracers have been an effective tool in determining allochthonous and autochtonous sources of organic matter in sediments. They have been applied to identify possible sources of pollution produced by human activities and natural changes in the environment. In this context, this study aimed to identify the origin, transformations and recent accumulation of organic matter in the sediments of MMELS. Five short cores, two representing each lagoon and one the fluvial end-member (Mundaú River), were analyzed for the vertical distribution of clay, silt and sand, organic carbon, the C/N ratio, 13C and lignins. The parameters showed that the sedimentary organic matter in the lagoons originated largely from its own phytoplanktonic primary production. However, the presence of lignin, albeit at low concentrations, indicated the presence of allochthonous plant material. In Mundaú River the presence of material derived from woody angiosperms was evident, while the lagoons exhibited a mixture of woody and non-woody materials, without a clear distributional pattern along the vertical profiles. The (Ad/Al)v ratios showed that the lignins were subject to a certain degree of degradation, contributing to a possible reduction in their total concentration and changes in the lignin-phenol S/V and C/V ratios. The application of the LPVI index (Lignin-Phenol Vegetation Index) for lignin-phenols allowed for a better understanding on the evolution of terrestrial material sources to the system, with a clear transition from woody angiosperms, representing the original vegetation in the drainage basin, to non-woody angiosperms, corroborating the expansion of sugar cane cultivation in the region. In addition, the results of organic matter accumulation in the lagoon’s sediments showed an increase of primary productivity in the more recent layers at the top of the cores, likely reflecting the effects of agricultural and urban expansion in MMELS
Whittaker, Thomas Edward. "High-Resolution Speleothem-Based Palaeoclimate Records From New Zealand Reveal Robust Teleconnection To North Atlantic During MIS 1-4." The University of Waikato, 2008. http://hdl.handle.net/10289/2575.
Повний текст джерелаCampos, Marília de Carvalho. "Variabilidade milenar da Corrente do Brasil e do clima da América do Sul durante o último período glacial." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/100/100136/tde-27072016-113954/.
Повний текст джерелаThe Brazil Current (BC) represents the southern branch of the bifurcation of the South Equatorial Current that interacts with the southeastern Brazilian continental margin. Sea surface temperature at BC region plays an important role in controlling the intensity and position of the South Atlantic Convergence Zone, which represents one of the main componets of the South American Monsoon System (SAMS). This atmospheric system is responsible for summer precipitation in a large sector of South America, and, therefore, it is a natural feature of great importance for the national and international political-economic context. Moreover, the BC is markedly influenced by the Atlantic Meridional Overturning Circulation (AMOC) whose past oscillations generated marked global abrupt climatic changes. Presently, the few paleoceanographic records available from the western South Atlantic do not allow a detailed reconstruction of the changes that happened in the BC during the last glacial cycle. This MSc. dissertation aimed at reconstructing the variability of the BC around 32°S during the events Heinrich Stadial (HS) 3 and 2, as well as its impacts on the climate of southeastern South America. Therefore, we investigated one marine sediment core collected in the southern Brazilian continental margin, under the influence of the BC. For this core we produced an age model based on 14C ages, downcore records of carbon and oxygen stable isotopes and Mg/Ca, both in tests of planktonic foraminifera, and X-ray fluorescence in bulk sediment samples. During HSs (notably during HS2), the records show marked increases in sedimentation rate as well as in ln(Ti/Ca) and ln(Fe/Ca), and decrease in the stable carbon isotopic composition as well as sea surface temperature and salinity. Such changes were releted to the weakening of the AMOC, the intensification of the Southern Ocean upwelling, and the strengthening of the SAMS. The occurrence a w-structure in our HS records as well as in North Atlantic and South American records, suggest that such structure is a pervasive feature of HS2, and possibly also HS3
Partin, Judson Wiley. "Stalagmite reconstructions of western tropical pacific climate from the last glacial maximum to present." Diss., Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/22556.
Повний текст джерелаFrainer, André. "Ecosystem functioning in streams : Disentangling the roles of biodiversity, stoichiometry, and anthropogenic drivers." Doctoral thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-82914.
Повний текст джерелаThompson, Alexandra E. "Stable carbon isotope ratios of nonmethane hydrocarbons and halocarbons in the atmosphere." 2003. http://wwwlib.umi.com/cr/yorku/fullcit?pNQ82831.
Повний текст джерелаTypescript. Includes bibliographical references (leaves 276-287). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pNQ82831.
Veefkind, Ruben Jelmar. "Carbon isotope ratios and composition of fatty acids: tags and trophic markers in pelagic organisms." Thesis, 2003. http://hdl.handle.net/1828/8043.
Повний текст джерелаGraduate
Beaumont, Julia, J. Bekvalac, Sam Harris, and Catherine M. Batt. "Identifying cohorts using isotope mass spectrometry: the potential of temporal resolution and dietary profiles." 2021. http://hdl.handle.net/10454/18340.
Повний текст джерелаArchaeological skeletal material from most sites represents a cross-sectional, opportunistic sample of the burials. These are influenced by the proportion and area of the site which is excavated, the taphonomic conditions and survival of tissues. This may not be representative of the population, and in an attritional cemetery may represent a long period of use, during which humans will have differing life-courses. Here we describe a commingled skeletal assemblage, the only human remains recovered from the historically significant medieval site of St Stephen’s Chapel, Palace of Westminster, London. Using carbon (δ13C) and nitrogen (δ15N) stable isotope ratios of bulk bone collagen and incremental dentine to investigate dietary life histories from 5 individuals, we combine the evidence with radiocarbon dating to assign them to two different temporal cohorts.
The full-text of this article will be released for public view at the end of the publisher embargo on 15 Feb 2023.
Craig-Atkins, E., Jacqueline R. Towers, and Julia Beaumont. "The role of infant life histories in the construction of identities in death: An incremental isotope study of dietary and physiological status among children afforded differential burial." 2018. http://hdl.handle.net/10454/16540.
Повний текст джерелаObjectives Isotope ratio analyses of dentine collagen were used to characterize short-term changes in physiological status (both dietary status and biological stress) across the life course of children afforded special funerary treatment. Materials and Methods Temporal sequences of δ15N and δ13C isotope profiles for incrementally-forming dentine collagen were obtained from deciduous teeth of 86 children from four early-medieval English cemeteries. Thirty-one were interred in child-specific burial clusters, and the remainder alongside adults in other areas of the cemetery. Isotope profiles were categorized into four distinct patterns of dietary and health status between the final prenatal months and death. Results Isotope profiles from individuals from the burial clusters were significantly less likely to reflect weaning curves, suggesting distinctive breastfeeding and weaning experiences. This relationship was not simply a factor of differential age at death between cohorts. There was no association of burial location with stage of weaning at death, nor with isotopic evidence of physiological stress at the end of life. Discussion This study is the first to identify a relationship between the extent of breastfeeding and the provision of child-specific funerary rites. Limited breastfeeding may indicate the mother had died during or soon after birth, or that either mother or child was unable to feed due to illness. Children who were not breastfed will have experienced a significantly higher risk of malnutrition, undernutrition and infection. These sickly and perhaps motherless children received care to nourish them during early life, and were similarly provided with special treatment in death.
University of Sheffield Early Career Researcher Scheme by a grant awarded to ECA in 2014-15.
Beaumont, Julia, and Janet Montgomery. "Oral Histories: a simple method of assigning chronological age to isotopic values from human dentine collagen." 2015. http://hdl.handle.net/10454/7172.
Повний текст джерелаBackground: stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) in bone and dentine collagen have been used for over 30 years to estimate palaeodiet, subsistence strategy, breastfeeding duration and migration within burial populations. Recent developments in dentine microsampling allow improved temporal resolution for dietary patterns. Aim: We propose a simple method which could be applied to human teeth to estimate chronological age represented by dentine microsamples in the direction of tooth growth, allowing comparison of dietary patterns between individuals and populations. The method is tested using profiles from permanent and deciduous teeth of two individuals. Subjects and methods: using a diagrammatic representation of dentine development by approximate age for each human tooth (based on the Queen Mary University of London Atlas) (AlQahtani et al., 2010), we estimate the age represented by each dentine section. Two case studies are shown: comparison of M1 and M2 from a 19th century individual from London, England, and identification of an unknown tooth from an Iron Age female adult from Scotland. Results and conclusions: The isotopic profiles demonstrate that variations in consecutively-forming teeth can be aligned using this method to extend the dietary history of an individual, or identify an unknown tooth by matching the profiles.
Beaumont, Julia, Janet Montgomery, Jo Buckberry, and Mandy Jay. "Infant mortality and isotopic complexity: new approaches to stress, maternal health and weaning." 2015. http://hdl.handle.net/10454/7140.
Повний текст джерелаBunney, E. "Leaf wax n-alkane variation in Dodonaea viscosa along an environmental gradient." Thesis, 2015. http://hdl.handle.net/2440/117963.
Повний текст джерелаThe variation in distribution and abundance of leaf wax n-alkanes has been proposed as a proxy for palaeoclimate. Understanding environmental controls on the variation in distribution and abundance of leaf wax n-alkanes is therefore necessary to determine if this is a robust tool for extracting climatic information from palaeo archives. Results of previous work to create a modern baseline for this proxy have, in some cases, been confounded by differences in species or plant type between sites or along gradients. This study investigates leaf wax n-alkane variation within a species of Australian shrub, Dodonaea viscosa, which inhabits a wide range of climatic conditions. Leaf wax n-alkane data from 43 individuals of D. viscosa were analysed from a climatic gradient ranging from central Australia to Kangaroo Island, with a mean annual temperature range of 13.9—22.7 °C and precipitation range of 164—808 mm/yr. Concentration of n-alkanes increase with increasing temperature along the gradient. Annual mean aridity index has the strongest relationship with the average chain length (ACL) of leaf wax n-alkanes and suggests that water availability is a strong driver of variation in ACL. In addition to n-alkane data, carbon isotope ratio (δ13C) and specific leaf area (SLA) data were measured to determine if this species shows predictable responses to these established and climatically sensitive leaf traits. Predicted responses in δ13C and SLA are observed in this species. Only weak effects of subspecies on leaf trait relationships with climate are found in this study. Scanning electron microscopy was used to qualitatively assess differences in leaf wax microstructure with climate and produced inconclusive results. Distributions of leaf wax n-alkanes have great potential as a proxy for palaeoclimate. Results presented here support the use of n-alkane ACL variation to detect aridity rather than temperature.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2015
Crowe, Douglas Edward. "Geochemistry of volcanogenic massive sulfide and high-grade Au granite-hosted ore deposits, southern Alaska ; and, Development and application of laser microprobe techniques for analysis of sulfur, carbon and oxygen isotope ratios." 1990. http://catalog.hathitrust.org/api/volumes/oclc/23277076.html.
Повний текст джерелаTypescript. Four plates on folded leaves in pocket. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.