The main focus of this thesis has been directed towards developing novel surface-confined transition metal complexes for applications in heterogeneous catalysis and for the preparation of anisotropic particle surfaces. The first part describes the heterogenization of a homogeneous transition metal-based catalyst tetraphenyl cobalt porphyrin (CoTPP) on silicon wafers and on silica particles. The activity in hydroquinone oxidation for the silica particle-immobilized CoTPPs was found to be increased 100-fold compared to its homogeneous congener whereas the silicon wafer-immobilized CoTPPs achieved lower activity due to the formation of clusters of catalyst molecules on the support surface as detected with atomic force microscopy (AFM). The second part of this thesis describes the development and characterization of anisotropic particle-surfaces by electrochemical site-specific oxidation of surface-confined thiols. Reactive patches or gold gradients could be obtained on the particle surfaces depending on the type of working electrode used and on the electrolyte composition. The particle surface functionalities were characterized with X-ray photoelectron spectroscopy (XPS) and the particle-surface-confined patches and gradients were conjugated with proteins to obtain fluorescence for investigation using fluorescence microscopy. Gold-functionalized siliceous mesocellular foams were further demonstrated to be highly efficient and selective catalysts in the cycloisomerization of 4-alkynoic acids to lactones. The final part of this thesis describes the preparation and characterization of palladium nanoparticles heterogenized in the pores of siliceous mesocellular foam. The nanoparticles were analyzed with transmission electron microscopy (TEM) and found to have a size of 1-2 nm. Primary- and secondary benzylic- and allylic alcohols were oxidized by the heterogeneous palladium nanoparticles in high to excellent yields using air atmosphere as the oxygen source. The nanopalladium catalyst was used up to five times without any decrease in activity and the size of the nanoparticles was retained according to TEM. / <p>At the time of doctoral defence the following paper were unpublished and had a status as follows: Paper1: Manuscript; Paper 4: Manuscript</p>

Les îles fournissent de bonnes opportunités pour étudier l'émergence de la biodiversité de part leur contexte spatial facilement appréhendable. Nous avons étudié une espèce de passereau endémique de l'île de la Réunion : le Zostérops des Mascareignes, Zosterops borbonicus. Cette espèce présente une extraordinaire variabilité de la couleur de son plumage à une échelle spatiale rarement documentée chez les oiseaux. L'analyse des patrons de variations génétiques et phénotypiques le long de gradients altitudinaux et au travers des zones hybrides séparant les différentes formes de couleur de l'espèce a permis de mettre en évidence le rôle de différents facteurs (sélectifs, historiques et neutres) dans l'émergence et le maintien de cette diversité. / Due to their well defined spatial context, islands are perfect places to study the emergence of biodiversity. Here, we studied a endemic passerine from the island of Réunion: the Mascarene White-eye. This species shows an extraordinary pattern of plumage colour variation at a spatial scale which have rarely been documented in birds. The joint analysis of genetic and phenotypic pattern of variation along environmental gradients and across hybrid zones separating the colour forms allowed us to show the role of various factors (selective, historical and neutral) in the emergence and maintenance of this diversity.

We present a novel method for building 3D models from a user sketch. Given a 2D sketch as input, the approach aligns and deforms a chosen 3D template model to match the sketch. This is guided by a set of user-specified correspondences and an algorithm that deforms the 3D model to match the sketched profile. Our primary contribution is related to fitting the 3D deformable geometry to the 2D user sketch. We demonstrate our technique on several examples. / Science, Faculty of / Computer Science, Department of / Graduate

As global change alters the chemical and physical dynamics of the ocean, it is increasingly necessary to determine ecological responses across environmental gradients. The benthic ecosystems of fjords often contain a multitude of environmental gradients conducive to multivariate field studies. In this thesis, I describe the benthic community structure of two British Columbian fjords in relation to markedly different environmental variables. In Chapter 2, I show a strong correlation between suspension-feeder abundance and flow structure on the steep fjord walls of Douglas Channel, BC. I also describe distinct assemblages with depth and with location along the fjord head-mouth axis. Using a suite of biological traits, I show that the deep portion (> 400 m depth) of the most seaward site is the most taxonomically and functionally diverse in the fjord. My results suggest fjord walls form an expansive ecosystem containing diverse and dense assemblages of suspension feeders relevant to the flow of energy through fjord basins and as biodiversity reservoirs. In Chapter 3, I extend a long-term hypoxia time-series (2006 -2016) to document the response of soft-bottom epibenthic megafauna of Saanich Inlet, BC to a prolonged hypoxic event in 2016 that caused abundance declines, community aggregation and shifts in species composition more extreme than those seen in the 2013 hypoxia cycle. I also assess community threshold responses along the oxygen gradient; I found community transitions consistent across years and with Northeast Pacific oxygen thresholds based in ecophysiological studies. Taken together, these studies show a strong coupling between oceanographic conditions and the community structure of fjord benthos. I suggest that climate-driven alterations in North Pacific oceanographic regimes may portend major changes in fjord ecosystems. / Graduate

Temperature differences of about 5, 10, and 15 V, were applied to uniformly packed and insulated horizontal column of Millville silt loam soil using mean temperatures near 13, 14, 15, 16, 17, 18, 19, 20 and 23.5 C. The temperature distribution along the soil column was determined using copper constantan thermocouples. Soil samples were taken to determine volumetric moisture content, and soil water potential, using the vapor pressure psychometer technique. The thermodynamic flow equation of Taylor and Cary, (1964) was used to calculate the hydro-thermal transfer coefficient (β) as given by: -β=(d(μW)Τ)/dlnT where (μW)Τ is the constant temperature water potential and Τ the temperature in °K. The net transfer of moisture from the warm to the cold face of the soil column was found to depend upon the temperature difference, the mean temperature of the system, the water potential distribution that resulted and the average soil water potential as predicted by the equation. The hydro-thermal-transfer coefficient (B) was found to depend primarily on the average water potential with secondary dependence on the mean temperature. The hydro-thermal transfer coefficient was found to be small and nearly constant at high soil moisture potential where water was moving mainly in the liquid phase. At low soil water potentials the hydro-thermal transfer coefficient was again nearly constant and reached high values. In this situation water is moving mostly in the vapor phase. In the zone of water potential where significant water movement is taking place, in both liquid and vapor phases, the influence of the coefficient on the movement was not determined because of the rapidly changing relations.

Our lives are dominated by a complex visual world, and spatially selective attention allows us to process only the most relevant information. Previous evidence suggests that if possible locations of stimulus presentation are delineated, attention affects processing in a spatially graded manner. This gradient is seen in both behavioral measures and in visual evoked potentials (VEPs). Stimuli presented close to cued regions elicit faster responses and larger VEPs than those presented farther away. However, both position in the visual field and allocation of attention may contribute to the observed gradients. These relative contributions can be distinguished by comparing responses on physically identical trials when attention is directed to locations at various distances from the stimuli. In the current study, participants attended to one of 12 squares arranged in a circle around fixation. Letters appeared individually, each in one of the squares; 80% were O’s (standards) and 20% were X’s (deviants). Participants were instructed to press a button when an X appeared at the attended location. The largest amplitude N1s (150-200 ms) were observed when participants attended to the location where a standard was presented. VEPs elicited by standards showed evidence of asymmetric attentional gradients. Specifically, the gradient of facilitation spread down more than up. Results also showed that attention had differential effects on the stages of processing indexed at specific time windows. These results confirm that attention can be applied to visual processing in a spatial gradient, reveal its asymmetric distribution, and elaborate on the timing of its selectivity.

No description available.

Wakes are present in many engineering flows. These flows include internal flows such as mixing chambers and turbomachinery as well as external flows like flow over high-lift or multi-element airfoils. Many times these wakes are exposed to flow conditions such as adverse pressure gradients and streamline curvature that alter the mean flow and turbulent structure of the wake. The ability to understand how pressure gradients and streamline curvature affects the structure of the wake is essential to predicting how the wake will affect the performance of the application in which it is found. The effects of pressure gradients and curvature of low-speed wakes has been extensively documented. As the transonic flow regime is becoming of more interest as gas speeds in turbomachinery increase this work fills a void in the body of wake knowledge pertaining to curved wakes in high speed flows. An under-resolved direct numerical simulation of transonic wake flow being shed by a cambered airfoil in the presence of adverse pressure gradients and streamline curvature is therefore presented here. It was observed that the turbulence characteristics arising from the cambered airfoil that generates the wake dominate the evolution of the wake for different distances downstream depending on the component of the Reynolds stresses that is being considered. These characteristics dissipated the most quickly in the shear stresses and endured the longest in the tangential normal stresses. Previous work in low-speed wakes has indicated that curvature creates new production terms that translate into asymmetry in the profiles of the wake. Curvature was observed to have limited influence on the evolution of the streamwise normal stresses and an extensive impact on the tangential normal stresses. The transport of the Reynolds shear stresses indicate that the asymmetry in this stress is caused indeed by curvature but through turbulent diffusion and not production. The k-ε turbulence model overpredicted the effect of curvature on the turbulence stresses in the wake. This led to accelerated wake decay and spread compared to the UDNS data.

The peninsula effect is a pattern of diversity wherein species richness decreases along a peninsula from base to tip and is attributed to three mechanisms: historical processes, habitat gradients, and immigration-extinction equilibrium. Numerous studies have reported conflicting results involving the existence, cause, and validity of the peninsula effect in part because they did not account for effects of history or habitat on species richness patterns and because most previous research focused on organisms that actively disperse, which could confound results with behavioral habitat selection. Florida poses an excellent opportunity to study the peninsula effect because of its geological history and its unique ridges have similar histories (e.g. age, elevation, and sediment). Habitat changes down the peninsula, from a warm temperate climate in the north to a subtropical climate in the south. I studied freshwater crustaceans in isolated wetlands because crustaceans are diverse and disperse passively among these discrete habitats. My study design and statistical analyses controlled for two of the three mechanisms (habitat and history) that may generate a peninsula effect to better test for the third hypothesis (immigration-extinction equilibrium) on the Florida peninsula. Thirty-one wetlands were sampled for crustaceans monthly from November 2004 through April 2005, or until a site dried. Human disturbance was minimized by choosing isolated, ephemeral wetlands located within state reserves, parks, and forests located on four major ridges: Trail, Brooksville, Mount Dora and Lake Wales. I measured several environmental variables to assess habitat variation among sites. Limnological parameters included temperature, pH, dissolved oxygen, conductivity, chlorophyll á, pheophytin, total nitrogen, total phosphorus, and total hardness. Other habitat variables included surface area, distance to nearest water body, fish presence or absence, hydroperiod, total transmitted light and canopy openness. Crustacean species were identified to the lowest practical taxonomic level (typically species) and recorded as present or absent. A total of 53 different crustaceans were identified, including 41 cladocerans, 10 copepods, and 2 ostracods. In a multiple regression, environmental variables and sampling effort accounted for 57% of the variation in species richness. Regression of remaining variation (residuals) against latitude, which measures position along the peninsula, was not statistically significant. The same pattern was obtained when the sequence of regressions was reversed. Therefore, the peninsula effect does affect the species richness of freshwater crustaceans inhabiting ephemeral wetlands on Florida's ridges. Instead, variation in species richness was determined mainly by habitat differences, particularly the complex interaction of phosphorus levels, isolation, fish presence or absence, and hydroperiod. This study may serve as a model for more thorough analyses of mechanisms (history, habitat, and immigration-extinction) of a peninsula effect in other taxa.

No description available.