Isotopic Variation 18o
Mostrando 1-8 de 8 artigos, teses e dissertações.
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1. Isotopic signatures (δ 13C and δ15N) of muscle, carapace and claw in Phrynops geoffroanus (Testudines: Chelidae)
The isotopic composition ( δ13C and δ 15N) of muscle, carapace and claw was determined from six wild individuals of Phrynops geoffroanus (Schweigger, 1812) in order to verify the variation between those tissues. The mean values of δ13C e δ 15N were, respectively, -19.48 ± 0.81‰ (-20.8 - -18.64‰) and 7.23 ± 0.67‰ (6.49 - 8.3‰) for muscle, -16.52
Zoologia (Curitiba). Publicado em: 2011-06
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2. Isotope characterization of the hydrologic cycle components in four sub-basins of the Piracicaba river basin (SP) / Caracterização isotópica dos componentes do ciclo hidrológico em quatro sub-bacias pertencentes à bacia do Rio Piracicaba (SP)
This project had the objective to investigate the oxygen (?18O) and hydrogen (?D) isotopic variation of shallow unconfined aquifers in four regions, in transects defined from the river to the limit of the drainage area. The transects were established within a topographical gradient in four sub-catchments of the Piracicaba river hydrographic basin. The popula
Publicado em: 2008
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3. Variação na composição isotópica do metano (CH4) em sedimentos de igarapés na Amazônia Oriental / The variation of isotopic composition of methane (CH4) in stream sediments of Eastern Amazon
O estudo da composição isotópica de metano (δ13CH4) fornece valiosa informação para o entendimento dos processos de produção, emissão e ciclagem desse gás nos ecossistemas. Neste trabalho, foram analisadas a concentração e as variações da composição isotópica do metano presente em bolhas de gás formadas no sedimento de igarapés. A comp
Publicado em: 2005
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4. Ecosystem rooting depth determined with caves and DNA
Belowground vertical community composition and maximum rooting depth of the Edwards Plateau of central Texas were determined by using DNA sequence variation to identify roots from caves 5–65 m deep. Roots from caves were identified by comparing their DNA sequences for the internal transcribed spacer (ITS) region of the 18S–26S ribosomal DNA repeat agains
The National Academy of Sciences.
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5. INTERBASE VIBRATIONAL COUPLING IN G:C POLYNUCLEOTIDE HELICES
The carbonyl stretching vibrations of G and C residues undergo frequency changes when a helical complex is formed from nonordered G and C components. We have prepared a series of two-stranded G:C helices having chemical and isotopic (18O) substitutions which lead to variation of the observed vibrational frequencies. Infrared spectra of these helices clearly
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6. Variation in the Oxygen Isotope Ratio of Phloem Sap Sucrose from Castor Bean. Evidence in Support of the Péclet Effect1
Theory suggests that the level of enrichment of 18O above source water in plant organic material (Δ) may provide an integrative indicator of control of water loss. However, there are still gaps in our understanding of the processes affecting Δ. One such gap is the observed discrepancy between modeled enrichment of water at the sites of evaporation within t
American Society of Plant Physiologists.
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7. Oxygen and Hydrogen Isotope Ratios of Water from Photosynthetic Tissues of CAM and C3 Plants 1
Water samples from photosynthetic tissues of C3 and Crassulacean acid metabolism (CAM) plants that grew together in the field were extracted and the stable oxygen and hydrogen isotope ratios determined. During the day, 18O/16O and deuterium/hydrogen (D/H) ratios of water from CAM plants were lower than those observed in water from C3 plants. The patterns of
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8. Water Relations Link Carbon and Oxygen Isotope Discrimination to Phloem Sap Sugar Concentration in Eucalyptus globulus
A strong correlation was previously observed between carbon isotope discrimination (Δ13C) of phloem sap sugars and phloem sap sugar concentration in the phloem-bleeding tree Eucalyptus globulus Labill. (J. Pate, E. Shedley, D. Arthur, M. Adams [1998] Oecologia 117: 312–322). We hypothesized that correspondence between these two parameters results from cov
American Society of Plant Biologists.