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 719 for “"speciation"”.
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Arsenic Speciation in Food
A high performance liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC-ICP-MS) method has been developed for the separation and quantification of ~g kg-1 levels of arsenobetaine, monomethylarsonic acid (MMAA), dimethylarsinic acid (DMAA) , arsenite and arsenate. Using this …
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IODINE SPECIATION IN MARINE AEROSOL
… aerosol phases and to date, what controls iodine speciation, the interactions and roles of individual iodine species are not well understood. This research aims to identify key controls on iodine speciation in marine aerosol. Effects of filter types on iodine and extraction methods were tested to …
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Speciation of chromium in environmental matrices.
… results obtained illustrate the difficulties of speciation analysis in such complex matrices. A method based on single extraction with 0.43 mol L[-1] acetic acid followed by on-line ion chromatography with chemiluminescence detection was found to be simple, sensitive, free of interferences, and …
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Tritium speciation in nuclear decommissioning materials
Tritium is a by-product of civil nuclear reactors, military nuclear applications, fusion programmes and radiopharmaceutical production. It commonly occurs, though not exclusively, as tritiated water (HTO) or organically-bound tritium (OBT) in the environment but may exist as other forms in …
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Evolutionary dynamics of speciation and extinction
… variability, and competition, the dynamics of speciation and extinction is investigated. The simulated organisms evolve according to the reaction-diffusion rules of the 2D directed percolation universality class. Offspring are generated according to one of three reproduction schemes. Mate …
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Gel electrophoresis for elemental speciation purposes
This work has shown that gel electrophoresis is a relevant fractionation method for trace elements bound to or complexed by macromolecules. Furthermore, detection methods of the trace elements that do not rely on the use of radiotracers were applied, making this combination relevant for materials …
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Speciation Genomics in Australian Meliphagoid Birds
The speciation process proceeds through a continuum of increasing genomic divergence and decreasing gene flow between populations. While sampling across hybrid zones provide insight for an intermediate stage of speciation, comparative studies of multiple contact zones between populations at …
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Speciation Genomics in Australian Meliphagoid Birds
The speciation process proceeds through a continuum of increasing genomic divergence and decreasing gene flow between populations. While sampling across hybrid zones provide insight for an intermediate stage of speciation, comparative studies of multiple contact zones between populations at …
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A higanyspeciáció lehetőségei = Challenges in mercury speciation
A higany módosulatanalitika legnagyobb kihívását a minták igen kis higany koncentrációja jelenti. Olyan módosulatanalitikára alkalmas rendszereket kell tehát építeni, melyek érzékenysége és szelektivitása megfelel az adott feladat elvárásainak. Doktori munkám során a higanyspeciáció lehetségeit …
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Copper speciation in estuaries and coastal waters
… a commonly used approach to determine metal speciation (competitive ligand exchange adsorptive cathodic stripping voltammetry, CLE-ACSV). Using this new approach to chemical Cu speciation and an old approach to physical Cu speciation (filtration), I show that riverine humic substances, …
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A Geographic Mosaic of Speciation in Eurosta solidaginis
Ecological speciation occurs when divergent selection in different habitats creates strong selection for reproductive isolation which counteracts the homogenizing effects of gene flow between populations using those different habitats. Multiple divergent selection pressures can affect isolation and …
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Copper and Zinc Speciation in the Tamar Estuary
The chemical speciation of trace metals controls their potential bioavailability and therefore toxicity to exposed organisms. Despite previous studies demonstrating the ameliorative effects of dissolved organic carbon (DOC) on metal toxicity, the effectiveness of ligands from varying sources and of …
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The Speciation of Dissolved Uranium in Marine Waters
<p>Uranium has been used extensively for quantifying geochemical processes in the marine environment. Due to its low concentration, about 3.3 μg/1, some form of preconcentration is required for analysis. The two most widely used pre-concentration schemes are co-precipitation with iron hydroxide, …
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The role of a circalunar clock in speciation
… many contemporary studies now suggest that speciation with gene flow is not only possible, but perhaps more common than previously assumed. Phenotypes influencing both mating and ecology (magic traits) lie at the center of many simple models of sympatric speciation and may play important …
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Speciation genes in native New Zealand leafroller moths
This thesis tests predicted characteristics of speciation genes made by the 'genic view' of speciation. The genic view states that the genome of a species is mosaic, and is divided into regions that contribute to a speciation event (speciation genes) and regions that do not (neutral genes). These …
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XAS studies of metal speciation in hydrothermal fluids
Knowledge of metal speciation and thermodynamic properties underpins our capability to model metal transport and deposition in natural and engineered systems. Using synchrotronbased X-ray Absorption Spectroscopy and high temperature – high pressure experimental techniques, this project aims to …
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Solubility and speciation of plutonium(VI) with orthophosphate
Pu(VI) speciation and solubility with phosphate was examined at pH from 0.3 to 12.2, Pu(VI) concentrations from 5 $\times\ {\rm 10}\sp{-5}$ M to 1.3 $\times\ {\rm 10}\sp{-3}$ M and phosphate concentrations up to 0.6 M. Absorption spectroscopy, solubility experiments, scanning electron microscopy …
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Genetic architecture and ecological speciation in Heliconius butterflies
… of new species. However, when gene flow persists speciation must overcome the antagonism between selection and recombination: Specifically, if gene flow persists, recombination will break down the genetic associations between alleles that characterise emerging species and cause reproductive …
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