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Coastal environments are important in many ways: they provide food and energy for coastal communities, have a variety of unique biologic habitats, and influence global climate. These environments can change due to either anthropogenic or natural phenomena over a wide range of time scales. However, the often overlooked long-term (centennial to millennial) processes may be hidden behind short-term fluctuations observed today. The need for a reference baseline of coastal habitats provides a new opportunity for paleontology, which is ideally equipped to document the long-term trends and reconstruct historical and ancient environments and communities. However due to taphonomic processes such as decay and diagenesis, there will always be some bias inherent to the fossil record. This bias has been often viewed as a negative aspect, undermining the utility of paleontological data for retrieving ecological and environmental records. Yet, fossils are still one of the best sources of direct data about the past faunas and their ecosystems. To overcome the biases introduced by the fossilization process, researchers have used observations and experiments in modern systems as models to compare fossil deposits, a method called actualistic paleontology. Over recent years, such actuopaleontological approaches have been used increasingly to exploit distinct signatures of fossil deposits in environmental reconstructions, quantify effects of anthropogenic processes on invertebrate faunas and regional ecosystems, and even augment archaeological studies. Three studied included in this dissertation exploit different aspects of paleontological techniques to study coastal systems, including both Recent and fossil settings. Two of the studies use modern environments to serve as models for investigating preservation potential and potential biases that affect subfossil and fossil assemblages forming in intertidal environments, from whether certain fauna will be preserved to the biases inherent in a shell deposit. The final study, conducted at a fine geologic resolution, focuses on the morphology of a fossil ancestor of an extant mactrid bivalve that is ecologically important in many present-day coastal habitats and well-studied by ecologists and malacologists. The study attempts to quantify morphological effects of environmental changes that occur over geological time scales. / Ph. D.

Pistacia is an economically important genus because it contains the pistachio crop, P. vera, which has edible seeds of considerable commercial importance. The evolutionary history of the genus and the taxonomic relationships among the species are controversial and not well understood. This study that has been conducted on this genus to refine taxonomic and evolutionary relationship utilizing different types of data (including morphology, anatomy and molecular) The studied species were the following: Pistacia aethiopica J. O. Kokwaro, P. atlantica Desf., P. chinensis Bunge, P. eurycarpa Yaltirik, P. falcata Becc. ex Martelli, P. integerrima Stew. ex Brand., P. khinjuk Stocks, P. lentiscus L., P. mexicana HBK, P. mutica Fisch. & Mey., P. palaestina Boiss., P. terebinthus L., P. texana Swingle, P. vera L., and P. weinmannifolia Poiss. ex Franch. Phylogenetic analysis based on morphological data strongly supported the monophyly of Pistacia. The genus divided into two monophyletic groups. One group (Section Pistacia) contains P. atlantica, P. chinensis, P. eurycarpa, P. falcata, P. integerrima, P. khinjuk, P. mutica, P. palaestina, P. terebinthus, and P. vera while the other group (Section Lentiscus) contains P. aethiopica, P. lentiscus, P. mexicana, P. texana, and P. weinmannifolia. In anatomical analysis, all species had anomocytic stomata. In most species, the stomata density was higher on the abaxial surface than the adaxial. The ratio of abaxial to adaxial stomatal density varied from 0.0 to 1.7. Stomatal distribution may provide insights into how Pistacia species evolve in terms of leaf anatomy and respond to different climatic changes. Stomatal distribution changed (losing stomata on either surface) as the genus moved into regions of higher rainfall. This study revealed leaflets of P. vera, which have random orientation, were isobilateral, while leaflets of the other species were dorsiventral and were oriented horizontally. RAPD analysis showed that P. khinjuk and P. vera are very close species. This study provides more insights into understanding the evolution, taxonomy and genetics of this economically important genus. / Ph. D.

The rheology and development morphology of textured fluids have been investigated. The first fluid considered in this work was a liquid crystalline polymer consisting of isotropic and anisotropic solutions of poly-p-phenyleneterephthalamide (PPT) in sulfuric acid. The second textured fluid considered in this work was an immiscible polymer blend consisting of poly(ethylene terephthalate) (PET) and nylon 6,6. The role played by liquid crystalline order (LCO) and a polydomain texture on the rheology of PPT solutions was investigated. It was found that several of the rheological phenomena commonly attributed to liquid crystalline order in polymers (e.g., three region flow curve, negative steady state first normal stress difference, and oscillatory behavior at the start up of shear flow) were not observed in the solution in its anisotropic state. The solution in both its anisotropic and isotropic state exhibited a two region flow curve (Newtonian plateau and shear thinning region at rates ranging from 10^-4 to 10² sec^-I), a positive steady state first normal stress difference which increased with shear rate, and a transient shear stress which displayed a single overshoot before reaching a steady state value. The rheology of PET/nylon 6,6 blends was found to be a function of both polymer degradation and the two phase texture. An accelerated degradation rate was found for the blends relative to the neat polymers, and as a consequence, the values of the steady shear viscosity (η), magnitude of the complex viscosity |η*|, storage modulus (G') and steady state first normal stress difference (N₁) for samples melt blended in an extruder were lower than those of the neat polymers. Blends prepared by dry blending followed by mixing in a cone and plate device where the degradation occurring during extrusion was avoided were found to have a higher value of |η*| and G' and enhanced transient behavior relative to those of the neat polymers. Scaling of the transient stress indicated there was no intrinsic time constant for these blends at shear rates lower than the longest relaxation time of the neat polymers The theory developed by Doi and Ohta which describes the additional stresses arising as a consequence of interfacial tension in two phase systems was evaluated for its ability to model the rheology of the 2575 w/w PET/nylon 6,6 blend. The Doi-Ohta theory was found to be capable of qualitatively predicting the extra stresses arising as a result of the interfacial tension as observed in the steady state viscosity and steady state first normal stress difference and the transient stresses at the start up of steady shear flow. While the overshoot and undershoot of the stresses observed during stepwise changes of shear rate were not predicted, the scaling relation for the transient stresses predicted by the theory were found to hold for the blend using stepwise changes of shear rate at a constant step ratio. / Ph. D.

Causes for the differences in precipitation morphology observed and investigation. / Master of Science

Field evaluation of frozen-thawed stallion semen has been limited to tests such as post-thaw motility and morphology that are not only subjective but also evaluate only a small population of cells. Flow cytometry has provided a quick, repeatable, objective method of evaluating a large number of cells, including spermatozoa. Two experiments were designed to first validate the use of several flow cytometric tests on frozen-thawed stallion semen and then determine a model that may best explain variation in fertility. Comparing samples that were live and freeze-killed validated the flow cytometric tests. In experiment one, six ejaculates were collected from each of three stallions. The semen from each ejaculate was centrifuged and frozen in 0.5 ml polyvinyl chloride straws. Two straws from each ejaculate were thawed and evaluated. Semen was evaluated for post-thaw motility, morphology, mitochondrial activity using Rhodamine 123 (R123), plasma membrane integrity using propidium iodide (PI) and ethidium monoazide (EMA), and chromatin structure using the sperm chromatin structure assay (SCSA). Data was recorded as percentages for all but the SCSA for both experiment one and two. The extent of chromatin denaturation was calculated using the SCSA and the alpha-t population [at = red/(red +green) fluorescence]. From the alpha-t population, statistics were calculated such mean (Xat), standard deviation (SDat), percentage of cells outside (COMPat) the main alpha-t population and the mean green fluorescence (mean green) of the population. Results from experiment one demonstrated that all flow cytometric tests except EMA were able to distinguish between live and freeze-killed samples (p < 0.0001). Also the stallion accounted for most of the variation in samples when compared to ejaculate and straw within an ejaculate. Therefore two straws could be chosen at random from a stallion and evaluated in experiment two. In experiment two, twenty-nine stallions were evaluated using the same tests as experiment one excluding EMA. Fertility data was obtained from the 1998 or 1999 breeding season. Multiple linear regression was used to determine the best-fit model to predict overall pregnancy rate. SCSA and R123-PI assays accounted for the largest amount of variation in fertility (R² = 0.65, p < 0.0004). Within SCSA and the R123/PI assays Xat and PI staining had the highest contribution to this variation in fertility (R² = 0.11, R² = 0.47) respectively. The best-fit model for predicting fertility included the assay combination listed above and the interactions between SDat and mean green staining as well as R123 and mean green staining. Post-thaw motility and morphology did not account for significant variation in fertility (p = 0.22, p = 0.46) respectively. Based on this project post-thaw motility and morphology are poor predictors of fertility in frozen-thawed stallion semen. However, through the addition of SCSA and R123-PI to the routine evaluation of frozen-thawed stallion semen time and money may be saved in advance by identifying those stallions with poor post-thaw fertility. / Master of Science

Electron tomography is an invaluable technique with the capability of carrying out thorough 3D structural, chemical and morphological characterization of materials at nanometer scale. Tilting range, increment and reconstruction algorithms are three of the main factors affecting the quality of tomograms. An anisotropic degradation can be observed with restricted tilting range and increment. Therefore, this study was carried out to investigate the accuracy of the reconstruction results of MgO (cube-shape) generated by FBP, SART and SIRT tomographic algorithms under various reconstruction conditions, i.e. tilting range and increment. Examining the experimental data with known morphology permits quantitative determination of the accuracy of the reconstruction results by measuring the distortion of the cube in all directions. Moreover, distortion measurements in all directions reveal the relationship between level of distortion and the alpha tilt angle. / Master of Science

The gross intestinal configuration of the Nile tilapia intestine changed dramatically from a short, straight intestinal tube at hatch (day 0) to a very complex, coiling pattern first attained at 9 weeks post-hatch. During the developmental period, gut length increased from 90% to 410% of body length. The rate of increase in both intestinal and body lengths took place at an accelerating rate as the fish aged. The great intestinal length provides an advantage to the fish in digestion and absorption of nutrients present in the less energy-efficient herbivorous diet. Formulation of commercial diets to match the development of the fish's intestine may offer commercial advantage. Appearance, localization and distribution of intestinal enzymes were observed in the fish at hatch and at mature stages using enzyme histochemistry. At hatch (day 0), most gut enzymes were already present in the intestinal brush border. As the fish matured, activities of the enzymes were widely distributed along the intestinal tract. The early appearance and broad distribution of activities of all studied intestinal enzymes may be one factor contributing to the rapid growth rate characteristic of tilapia, which differs markedly from other fish species. To investigate the possibility of using alfalfa as a potential protein food replacement in tilapia, the effects of different levels of alfalfa in feeds on growth and intestinal enzyme activities were observed in the fish aged 3-15 weeks. Results demonstrated that replacing 20% and 40% of a commercial diet with alfalfa had an overall negative effect on body and intestinal growth, as well as the intestinal enzyme activities from age 3-9 weeks. Thus, using alfalfa as a food replacement is not optimal for fish of these young ages, but may yet be suitable for older fish. / Ph. D.

This thesis proposes guidelines for reestablishing the historic canal system on Rattanakosin Island, Bangkok as a public space system and a connector of key public spaces. The study examines the historic value and cultural symbolism of the canals through evolutionary morphological analysis, establishing that the canals are primary structural elements in the city, since they have retained the integrity of their physical form over time, and have come to hold cultural meaning for the Thai people. The canals have also accommodated different functions over time, in response to a changing urban context. There is potential for them to accept new functions as recreational spaces, connectors of key public spaces, and as tourist destinations. Typological analysis of structural characteristics of the canals yields seven canal types that have potential to accommodate public space functions. The study proposes guidelines for the seven canal types that will enhance these potentials and ensure the preservation of the canals' physical form. / Master of Landscape Architecture

Leptosphaerulina spp. are common fungi that have been reported to colonize several turfgrass species. Controversy exists regarding the relationship of Leptosphaerulina spp. and their turfgrass hosts. The fungus has been classified as a saprophyte, senectophyte, weak pathogen, and pathogen of turfgrasses. There has also been conflicting reports regarding the delineation of species within the genus Leptosphaerulina. Because of the uncertainty regarding the ecology and taxonomy of the genus in relation to turfgrasses the present study was undertaken. The ITS and EF-1á gene regions were sequenced and analyzed to compare to the multiple taxonomic schemes reported in the literature. The ITS region offered no resolution of species; however, the phylogeny of the EF-1á gene was consistent with the six-species model of Graham and Luttrell. Inoculation experiments were performed on unstressed and artificially stressed plants to determine whether the fungi are pathogens, senectophytes, or saprophytes of turfgrasses. Perennial ryegrass and creeping bentgrass plants were stressed by placing them in a dew chamber set at 38&ordm;C, 100% R.H., and no light for two and one days respectively. Plants were inoculated with cultures of Leptosphaerulina isolated from turfgrasses, and maintained at optimum conditions reported for infection and colonization. There was no visible difference between inoculated and uninoculated plants, and examination of cleared and stained leaves with a light microscope revealed spores that germinated and produced appressoria, but failed to penetrate the epidermal cells. The lack of infection and colonization suggests that Leptosphaerulina spp. are saprophytes of turfgrasses. / Master of Science