Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 21 for “"Enrichment factor"”.
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Natural abundance of ¹⁵N as a tool for assessing patterns of nitrogen loss from forest ecosystems
… nitrate concentration als[delta]caused enrichment of the plant-available ammonium pool. Finally, I tested the hypotheses: (1) that [delta]15 N in soil and litter increases across a spatial gradient of nitrate loss, and (2) that [delta]15 N in soil and litter are elevated when …
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Development of membrane extraction techniques for water quality analysis
… flow rates, as well as membrane material on enrichment factor and extraction efficiency were investigated. It was observed that solvent loss during extraction had significant impacts on enrichment factor and extraction efficiency. Continuous on-line monitoring of semivolatile organic …
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Isolation, structure, synthesis, and biosynthesis of selected bioactive microbial metabolites
… C, and ($carboxy$-$\sp{13}$C) AHBA gave an enrichment factor of 21 for the resonance corresponding to the C-21 carbonyl in the $\sp{13}$C NMR spectrum of labeled streptovaricin C. The optimization of incorporation of labeled glucose and the production of mutants of Streptomyces spectabilis …
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Affinity Maturation of the D1.3 Antibody Using Yeast Surface Display and Flow Cytometry
… YSD with the D1.3/M3 antibodies, a single-pass enrichment factor of 125-fold (+/-65-fold) was achieved, indicating excellent differentiation between clones of only slightly different affinity. Optimal equilibrium affinity screening of a randomly mutated D1.3 library was performed with and …
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An Assessment of Heavy Metal Concentrations in Surface Sediments from the Knysna Estuary
… including Pearson's Product–Moment correlation, enrichment factor analysis, and the assessment of heavy metal contamination were conducted between the variables to determine patterns of difference and similarity between the sites, as well as to determine the degree of contamination in the Knysna …
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Investigation of pollution coming from copper, lead, and zinc mining, and factors controlling mobility and bioavailability of pollutants at Ecton Hill, Staffordshire, UK
… unit of MS-17. In addition, soil specific factors, including organic matter content, organic carbon, pH, Eh, and cation exchange capacity were also measured. Spatial distribution maps were constructed using a GIS approach for the metals studied over the study area. Contamination and …
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Molecular engineering of new protein labeling methodology based on rational design and in vitro evolution
… Model selections demonstrated up to 1000-fold enrichment, and three rounds of selection on a randomized peptide library were performed. Third, we attempted to improve the kinetic efficiency of BirA through evolution by in vitro compartmentalization (IVC). Because the original IVC protocol based …
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Hyperspectral Reflectance and Stable Isotopic Nitrogen: Tools to Assess Forest Ecosystem Nitrogen Cycling
… in model performance with the addition of the enrichment factor (EF ="15NFol - "15NSoil). This research demonstrates the ability of hyperspectral reflectance to predict "15N and reveals the potential of "15N to be included in future models to predict fertilizer growth response.
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Pervaporation applications in food processing
… behaved similarly with respect to fluxes and enrichment factor. This suggests that even though essences are multicomponent solutions, the low concentrations in which the components are present preclude any multicomponent interaction. Thus, it is possible to work with simple solutions and …
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A revised monod-type rate law predicting variable sulfur isotope fractionation factors as a function of microbial sulfate reduction rate
… each rate was associated with a characteristic enrichment factor ( obs) of 0.9976, 0.9962, 0.9938, 0.9924 and 0.9903, respectively. This relationship was used to calibrate a coupled set of isotope-specific Monod rate laws that were modified to incorporate (1) both minimum ( 1 = 0.998) and …
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Unifying ecosystem concepts and mercury biomagnification in an estuarine environment using stable isotopes (delta-carbon-13 and delta nitrogen-15).
… prey, an average delta 13C- and delta15N-trophic enrichment factor (TEF) of 1.87 +/- 0.16‰ and 2.94 +/- 0.14‰, respectively, were calculated for the Miramichi River Estuary food web. Consistent with observations in other aquatic studies, a total of 4.7 delta15N-defined trophic levels …
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Faunal, sedimentological and geochemical indicators of dysoxia in Cretaceous marine sediments
… found to be the most reliable of the trace-metal enrichment proxies studied and altered numerical boundaries are proposed for Ua , U/Th, V/Cr and Ni/Co. Of the Fe-S-C systematics indicators, Total Organic Carbon and the Indicator of Anoxia are found to provide the greatest definition between …
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Optimization and analysis of the laser isotope separation technique SILEX and ensuing proliferation ramifications
… gas, and reportedly allows for high separation factors relative to other isotope-separation processes. Industry interests have argued that it could be readily commercialized. This topic is of particular interest because laser isotope separation technology has seen an increase in interest and …
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In-situ measurement of denitrification in the Elk Valley aquifer
… NO₃¯-N from 2.4 to 43.5‰ and an isotopic enrichment factor of -20.4‰ also provide evidence of denitrification. An increase of 1.70 mmol/L in sulfate identifies pyrite as the electron donor for 61% of the observed denitrification with the remaining 39% attributed to heterotrophic processes …
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Chemical speciation and spatial distribution of heavy metals and their adsorption onto sediments of the Berg River, Western Cape, South Africa
… at the top and middle of the cores. Based on the enrichment factor (EF) and anthropogenic factor (AF) values, it is suggested that the sediments of the estuary are not polluted with Co, Mn, Cu, Ni, Zn and Fe but moderately to highly polluted with Pb, As, Cd and Cr. The data reported provide a …
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Enhanced membrane distillation : analytical and deionization applications
… in water. CNIM provided much higher levels of enrichment for the analytes of interest than did preconcentration using the plain membrane. Another set of experiments was then successfully conducted that demonstrated that CNIM-MD was applicable to the preconcentration of drug products in a polar …
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Application of platinum-group element (PGE) geochemistry to select geological problems
… zones, and their tectonic setting is a critical factor in determining their occurrence. However, not all porphyries give rise to economic mineralisation. Over 90% are barren, even though they share many features with the economic porphyries, so the critical unanswered question is "what controls …
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Application of platinum-group element (PGE) geochemistry to select geological problems
… zones, and their tectonic setting is a critical factor in determining their occurrence. However, not all porphyries give rise to economic mineralisation. Over 90% are barren, even though they share many features with the economic porphyries, so the critical unanswered question is "what controls …
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Assessment of Potential Temporal Impacts of “Land use Activities on Water Quality of the Luvuvhu River “Catchment, South Africa
… While the “Pollution Load Index (PLI), Enrichment Factor (EF), Contamination Factor (Ci f) and Geo-accumulation Index (Igeo) indicate that the level of contamination is low to moderate in most of the” sediment samples. In consideration of “the potential ecological risk, the LRC sediments …
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Aquatic macrophyte-derived biomarkers as palaeolimnological proxies on the Tibetan Plateau
… water of the summer precipitation. The apparent enrichment factor between water and n-alkanes was in range of previously reported ones (≈-130‰) at the most humid sites, but smaller (average: -86‰) at sites with a negative moisture budget. This indicates an influence of evaporation and …
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