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The fine structure of the basidiospores of Pluteus cervinus and Agrocybe acericola is described using TEM, SEM, and light microscopy.The basidiospore wall of Pluteus cervinus is bipartite. No surface ornamentation or germ pore is present. The protoplasm is surrounded by a typical membrane which lacks distinct invaginations. Spores contain much stored lipid, which is centrally located. Spores are uninucleated with the nucleus closely appressed to the cell membrane, located at the base of the spore near the hilar appendage. Mitochondria with few, well-delineated plate-like cristae are present. Endoplasmic reticulum (ER) is scant. Ribosomes occur regularly attached to the ER and outer mitochondrial membrane, as well as being densely packed throughout the cytoplasm. Various sized vacuoles containing an electron dense material are present. Microbody-like organelles are observed, which are probably glyoxysomes, since assays of malate synthase, a maker enzyme of the glyoxylate cycle, are positive.The basidiospore wall of Agrocybe acericola is composed of two distinct layers, both layers are continuous around the spores, at the germ pore the outer wall is very thin and the inner wall becomes thicker. The plasma membrane is appressed to inner wall and lacks invaginations. The protoplasm is densely packed with small granules, probably ribosomes and/or glycogen. Spores contain very little lipid with bipolar distribution. Mitochondria are well-defined and distributed in cytoplasm. Spores are binucleate with the two nuclei lying on a line nearly perpendicular to the long axis of the cell. Various size single membrane-bound vacuoles are widely distributed in the cytoplasm. These vacuoles were shown to contain acid phosphatase indicating lysosomal activity. Microbodies, probably glyoxysomes, are observed. Malate synthase assays are positive indicating the occurrence of the glyoxylate cycle. / Department of Biology

The effect of chain extender chemical structure on the physical and mechanical properties of thermoplastic polyurethane/urethaneurea elastomers was systematically investigated. Several series of materials were synthesised using 4,4' -diphenylmethane diisocyanate (MDI) and poly(tetramethylene oxide) glycol (PTMG), each series incorporating a particular class of chain extender compound. Elucidation of the influence of chain extender structural variations within each series was the principal objective of the investigation…

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Abstract The genetic diversity and identification of slow- and fast- growing soybean root nodule bacterial isolates from different agro-climatic regions in Mpumalanga, Limpopo and Gauteng Provinces of South Africa were evaluated. The 16S-rDNA-RFLP analysis of 100 rhizobial isolates and eight reference type strains placed the isolates into six major clusters, and revealed their site-dependent genomic diversity. Sequence analysis of single and concatenated housekeeping genes (atpD, glnII and gyrB), as well as the symbiotic gene nifH captured a considerably higher level of genetic diversity and indicated the dominance of Bradyrhizobium diazoefficiens and Bradyrhizobium japonicum in Mpumalanga, Limpopo and Gauteng Provinces. Gene sequence similarities of isolates with type strains of Bradyrhizobium ranged from 97.3 to 100% for the 16S rDNA, and 83.4 to 100% for the housekeeping genes. The glnII gene phylogeny showed discordance with the other genes, suggesting lateral gene transfer or recombination events. Concatenated gene sequence analysis showed that most of the isolates did not align with known type strains and might represent new species from South Africa. This underscores the high genetic variability associated with soybean Bradyrhizobium in South African soils, and the presence of an important reservoir of novel soybean-nodulating bradyrhizobia in the country. In this study, the grouping of isolates was influenced by site origin, with Group I isolates originating from Limpopo Province and Group II and III from Mpumlanga Province in the 16S rDNA-RFLP analysis.

The current generation of cosmological hydrodynamical simulations offer new levels of fidelity in galaxy formation and evolution that can be benchmarked against observations. However, it is crucial that the comparison between the simulation products and observations is performed on level-ground. Using mock-observations of galaxies from hydrodynamical simulations with observational realism, an image-based comparison is enabled between the simulations and modern galaxy surveys that allow galaxy properties to be derived consistently. A new methodology is presented that provides an unprecedentedly comprehensive suite of observational realism to synthetic images of galaxies from simulations and performs detailed decomposition of their morphological structures. The crux of the methodology is that the same procedure for image-based surface-brightness decompositions of galaxy structures is employed for the simulations and observations -- facilitating a fair and unbiased comparison of galaxy properties. The methodology is piloted on galaxies from the Illustris simulation and is designed to enable comparison with galaxies from the Sloan Digital Sky Survery (SDSS). The biases from observational realism on the decomposition results for the simulated galaxies are characterized in detail using several controlled experiments. Then, the decompositions are used in a comparison of the galaxy size-luminosity and bulge-to-total vs. total stellar mass relations. The comparisons show that galaxies from Illustris contain too many discs and too few bulges at low masses M*/M☉≤11 relative to the SDSS. A comparison of the photometric and kinematic bulge-to-total is also enabled by the methodology. The comparison suggests that photometry tends to systematically under-estimate the bulge fractions relative to the kinematics -- allowing no discernible connection to be made between photo-bulges and kinematic bulges. Several possibilities that may be driving the bulge deficit in Illustris' low-mass galaxies are discussed, though particle resolution is argued to be the main culprit. The methodology that is presented in this thesis has broad applications to comparisons between computational and observational galaxy astronomy and stands to provide a wealth of feedback between each community. / Graduate / 0606 / cbottrel@uvic.ca

Unsustainable energy sources are running out and global warming is getting worse. Therefore the need for renewable energy sources is growing. Solar cells are a popular options used as an energy source. Most popular are the inorganic photovoltaic cells. With their high efficiency and long lifetime, they make a very good energy source. Unfortunately the costs for inorganic solar cells are rather high. Organic solar cells can make a good replacement for inorganic photovoltaic. They are easy to make, light and rather cheap. In this thesis, the morphology of a model system of the active layer of organic solar cells will be discussed, using dip coating as well as spin coating as a technique to prepare the films. The films consist of a blend of poly(9,9-dioctylfluorenyl-2,7-diyl) and [6,6]-phenyl C61-butyric acid methyl ester in different ratios and different solvents. The films that were made were prepared by spin coating or dip coating a glass substrate. After analysing the samples using atomic force microscopy, fluorescence spectroscopy and absorption spectroscopy it was clear that the morphology, as well as the position of the polymer chains can be influenced by using different dipping speeds, ratios or solvents.

<p> The study of contemporary evolution and eco-evolutionary dynamics is classically defined in terms of genetic evolution, but the actual suite of processes driving contemporary trait change is likely much more complex than often credited. This dissertation considers additional mechanisms of trait change that might be important to an emerging model system for study of contemporary evolution and eco-evolutionary dynamics. Specifically, the research focuses on phenotypically plastic and demographic trait variation in Eastern and Western Mosquitofish (<i>Gambusia affinis</i> and <i>G. holbrooki</i>) facing the major ecological gradient of predation risk. Plasticity experiments employed a common-garden rearing design to manipulate fish predator cues experienced by individuals, their parents, or their grandparents and in turn quantify reaction norms in mosquitofish size, shape, and behavior. The two species of mosquitofish showed divergent plastic responses in behavior, with the relatively bolder <i>G. holbrooki</i> becoming even bolder in response to predator cues. In contrast, males and females within species showed parallel behavioral responses. Despite strong sexual dimorphism, both sexes and both species showed parallel patterns of plasticity toward streamlining of body shape when exposed to predators. Interestingly, mosquitofish also showed evidence of transmitting predator cues across generations, where female <i>G. affinis</i> become shyer and more streamlined when their parents or grandparents experienced predators. In contrast, male <i>G. affinis</i> showed little evidence of transgenerational plasticity and appear to rely more heavily on their own experience. Another set of field surveys and experiments with <i>G. hoibrooki </i> considered the potential role of sexual dimorphism and demographic variation in sex ratios as another form of trait variation with possible community and ecosystem consequences. Natural population surveys revealed female-biased sex ratios and higher primary production in the absence of predators. Mesocosm experiments suggested males and females differed in dietary preferences and that both sex ratio and density influence community responses. Although these findings support a need to expand the current eco-evolutionary synthesis to mechanisms beyond just genetic evolution, they also support some general patterns in these mechanisms and ways in which they might work with evolution to produce an even more dynamic interaction of ecology and trait change in nature.</p>