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BackgroundThere are different methods for rendering grass in real-time, for video games. This thesis looks at an algorithm that uses hardware tessellation to generate geometry during run time. These concepts are explained in more detail in the introduction chapter as well as the method chapter. The objectives problem that this thesis revolves around is this; When rendering grass using tessellation a lot of geometry is created. This means that the grass might be a bottleneck, meaning it eats too much performance. This applies especially when adding lighting to a scene dense with grass. Lighting requires a lot more computations, so adding this can create a difference, a "dip" in performance. To try and aid this dip, LOD in different forms will be added. Then tests will be carried out to see if the divide is lessened. This would allow for a lot of lighting to be used together with this expensive technique. LOD means a way to lessen the geometry being rendered through different algorithms so that the performance cost will not be as high. methods answer the relevant research questions, a literature review was carried out. This is to understand the relevant 3D techniques better. And also to learn more about rendering grass through tessellation. Then an implementation was conducted, with this experiment to test different LOD techniques with and without lighting. Each scenario was tested ten times and the average framerate was measured and put into charts.ResultsThe average framerate dropped when light sources were added in all of the tests. The binary tree consumed more RAM usage but aided the framerate more than the quadtree. The VRAM usage for the grass tessellation was around 100 MB.ConclusionsFor future work, it would be interesting to compare different ways of rendering grass for the sake of user value. Do people prefer tessellated grass when minimal lighting is applied? Or do people prefer quads to represent grass? The results did not showthat the LOD implemented solved the issue presented in this thesis.

Comparative DNA sequencing of matK, a maturase-encoding gene located within the intron of the chloroplast trnK gene, was evaluated for phylogenetic utility above the family level and within the grass family (Poaceae). There are three major objectives in the research. The first one is to study the utility of the matK gene in plant evolution. The second objective is to characterize the matK gene in the grass family. The last major goal is to address the phylogenetic questions in the Poaceae using the matK sequences from representatives of different grass groups. In order to study the potential application of matK to plant systematics above the family level, eleven complete sequences from GenBank representing seed plants and liverworts and nine partial sequences generated for genera representing the monocot families Poaceae, Joinvilleaceae, Cyperaceae, and Smilacaceae were analyzed. The study underscored the following useful properties of the matK gene for phylogenetic reconstruction: reasonable size (1500 bp), high rate of substitution, large proportion of variation at the first and the second codon positions, low transition-transversion ratio, and the presence of mutationally-conserved sectors. The use of different sectors of the gene and the cumulative inclusion of informative sites showed that the 3' region was the most useful in resolving phylogeny, and that the topology and robustness of the tree reached a plateau after the inclusion of 100 informative sites. The presence of a relatively conserved 3' region and the less conserved 5' region provides two sets of characters that can be used at different taxonomic levels from the tribal to the division levels. It also has demonstrated the potential of partial sequencing in resolving systematic relationships from the tribe to the division level. The matK gene in the Poaceae was characterized with complete sequences from 11 grass genera, representing 7 subfamilies and 11 tribes, and one outgroup (Joinvillea plicata, Joinvillaceae). The alignment of 1632 base pairs from 14 species yielded a data set of 601 (36.8)% variable sites and 246 (15.1%) informative sites. The variations at nucleic and amino acid levels evenly distributed throughout the entire gene, and the 5' region appears to have more variation than the 3' region. The changes at the third codon position are very low as compared to the total of the first and second positions. This has led to a similar variation pattern at nucleic and at amino acid levels. The average tr/tv ratio generated from 14 entire matK sequences is 1.29. It is intriguing to find that the tr/tv ratios were regionally related. RASA analysis of the alignment data indicated a relatively high phylogenetic signal in the data set of 14 taxa. In the two half analyses, while the tRASA of the 5' half of the matK gene (0.43) is not significant, the 3' of the matK gene showed a significant phylogenetic signal. Among the 5 sections of the 14 entire matK sequences, only the fourth sector contains a statistically significant phylogenetic signal. These results indicate that matK is a phylogenetically valuable gene and that the 3' region of the matK gene contains strong phylogenetic information. A single most parsimonious tree was obtained from the 246 informative sites of the 14 entire matK sequences. Seven major groups were well resolved on the most parsimonious tree, corresponding to the seven commonly recognized subfamilies: Aruninoideae, Bambusoideae, Centothecoideae, Chloridoideae, Panicoideae, Pooideae and Oryzoideae. Approximately 960 base pairs of the matK gene were sequenced from grass species representing 48 genera, 21 tribes, and seven subfamilies to reconstruct a phylogeny for the Poaceae. Joinvillea plicata (Joinvilleaceae) was used as an outgroup species. The aligned sequences showed that 495 nucleotides (51%) were variable and 390 (36%) were phylogenetically informative. RASA indicated that very significant phylogenetic signals exist in this data set. The cumulative addition of informative sites starting at the internal end of the sequences revealed that at 300 sites, tree topology and bootstrap values matched those of the consensus tree based on the entire sequence. Parsimony analyses using PAUP resulted in six most parsimonious trees and a strict consensus tree showing major lineages supported by high bootstrap values. These lineages corresponded to six subfamilies: Bambusoideae, Oryzoideae, Pooideae, Chloridoideae, Panicoideae, and Arundinoideae. The Bambusoideae, including woody and herbaceous taxa, diverged as the most basal lineage, and the monophyletic oryzoid species formed a sister group. The Chloridoideae, Panicoideae, Arundinoideae, and the centothecoid Zeugitis (PACC group) emerged as a monophyletic assemblage with 95% bootstrap support. The Aristideae branched off as a monophyletic line basal to the chloridoid clade. Stipeae appeared as a sister taxon to the Pooideae. The matK-based phylogeny did not reveal a major dichotomy in the family. The matK gene has provided sequence information sufficient for good resolution of the major grass lineages. / Ph. D.

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Ceftiofur sodium, a third generation cephalosporin, was studied to determine the potential of this drug as an alternative bacterial therapeutic agent for the aquaculture and ornamental fish industry. Grass carp, Ctenopharyngodon idella have been selected as the fish model for this study since they are a good representative for both foodfish and ornamental fish and are one of the major species grown worldwide. Pharmacokinetics of ceftiofur sodium after various routes of administration, histopathologic observations to detect possible toxic effects on the tissues involved in its metabolism and excretion, and the effects on the non-specific immune response were investigated in grass carp. For the pharmacokinetic studies, ceftiofur sodium was administered a single time to grass carp by four different routes : intracardiac (IC), intraperitoneal (IP), intramuscular (IM) and oral (PO) at a dosage of 8 mg/kg body weight. Serial blood samples were obtained and plasma samples were analyzed by high performance liquid chromatography for ceftiofur (as measured its metabolite, desfuroylceftiofur (DFC) and DFC-related metabolite concentrations). Disposition pharmacokinetic data were best described by a two compartment open model for IC and by a non-compartment model with no lag time for IP and IM administrations. Oral absorption of ceftiofur was not observed in this species. Following IC, IP and IM ceftiofur sodium administration, the final elimination half-lives, maximum plasma concentration, time to reach maximum concentration, volume of distribution and plasma clearance were 0.38, 0.45 and 13.86 hours ; 157.09, 31.54 and 8.86 mg/ml ; 0, 0.25 and 0.5 hours ; 0.09, 0.17, 0.53 l/kg ; and 0.21, 0.26, 0.26 ml/min.kg, respectively. Desfuroylceftiofur metabolite was highly bound with plasma protein at pH 7.0 and 8.0. For the histopathological studies, a single intramuscular dose of ceftiofur sodium at three different concentrations, 8 (1X), 40 (5X) and 80 (10X) mg/kg was administered to separate groups of grass carp for evaluation of the potential toxicity to major tissues involved in metabolism and excretion of this drug. These included the anterior kidney, posterior kidney, liver, and spleen. After 48 hours, lesions were seen in the posterior kidney at the highest dose of ceftiofur (10X). Morphological alterations observed microscopically included increased number of renal tubules, tubular necrosis and infiltration of inflammatory cells. No adverse effects on the glomeruli were observed at any concentration of the drug. For the immunotoxicity studies on the non-specific immune response, dosages of either 8 or 40 mg/kg body weight were administered intramuscularly. After 24 and 48 h, leukocyte number, phagocytic ability and H2O2 production were examined in the cells of the pronephros. The results showed that neither dosage had an effect on the number of leukocytes in the pronephros. Phagocytosis was also not significantly altered at either dosage in macrophages from the pronephros. Hydrogen peroxide production was not altered in the pronephros of fish dosed at 8 mg/kg, while at a dosage of 40 mg/kg, H2O2 production was significantly increased. In summary, ceftiofur sodium has potential as an efficacious chemotherapeutic agent for controlling bacterial infection in brood stock and ornamental fish at the recommended dose of 8 mg/kg. A dose as high as 40 mg/kg can be use with careful consideration. This dosage may not directly injure the posterior kidney but it may affect the non-specific immune response of the fish. / Ph. D.

Experiments were conducted in the field, greenhouse, and controlled environment chambers to study the effect of environmental factors on tillering, growth, and carbohydrate content of orchardgrass. Tillers of one genotype were studied with several variable factors (light, temperature, moisture,. nitrogen, and/or defoliation) in each of four experiments. Factorial treatment combinations were used in each of the four experiments to study single factors and interactions. Tillering declined to 73 and 26% of normal light when light intensity was reduced in the greenhouse and field, respectively. In the controlled environment chambers, tillering rates were higher with an 18-hour than for a 9-hour day with 3100 F.C. in both chambers. Soluble carbohydrates in the stubble were associated with tillering. There was a marked increase in water soluble carbohydrates as light energy increased up to normal sunlight. Ory matter production was associated with tillering and carbohydrate contents of orchardgrass, factors which increased tillering augmented clipping dry weights. Tillering and foliage growth were much higher when day temperature was 80*F. as compared with 60°F. There was a sharp increase in soluble carbohydrates with low temperature, but at the high temperature carbohydrates did not accumulate as they were apparently utilized for fast growth and tillering. Carbohydrate accumulation per se was not associated with tillering nor yields when temperatures were sub~-optimum for fast growth. Tillering was increased 30% by irrigation. Tillering of orchardgrass plants, defoliated to 1.5, 3, and 6 inches in combination with other treatments, showed increased tillering and dry matter production as defoliation intensities were relaxed. High tillering rates were associated with the magnitude of carbohydrates in orchardgrass stubble. Root development at the end of the experiment was much poorer for intensive defoliation as compared with lax defoliation. Nitrogen stimulated tillering and retarded soluble carbohydrate accumulation in orchardgrass stubbles, Nitrozen stimulated the production of new tissue and nitrogen compounds at the expense of stored carbohydrates in the stubbles. With slow orchardgrass growth under low nitrogen, soluble carbohydrates in the stubble accumulated. There was good evidence that soluble carbohydrates are directly associated with tillering and growth of orchardgrass when factors such as light, nitrogen, and water do not limit growth. Carbohydrate accumulatpeiro nse is not associated with tillering, if any environment growth factor is sub-optimum for tillering and growth. sub-optimum for tillering and growth. / Ph. D.

The most importunate problem in using bermudagrasses (Cynodon sp.) for turf in the northern extremity, where semitropical grasses are adapted, is winter survival. This research was primarily conducted to investigate the effects of deacclimation of dormancy, duration of dormancy, and freezing temperatures on survival of bermudagrasses. 'Tifgreen' bermudagrass taken from the field in February, 1976, was deacclimated for 0, 2, 4, or 8 days at 27C/13C (day/night). Subsequently, rhizomes and stolons were subjected to +2, 0, -2, -4, or -6C for 24 hours. One third of the samples from each treatment were planted after 0, 45, and 90 days storage at 2.8C±1.6C. Rhizomes and stolons subjected to -4 or -6C did not survive. Deacclimation of rhizomes up to 8 days augmented growth as compared to no deaccli~ation. Increased storage periods caused decreased rhizome growth. At +2 and 0C, the percent rhizome growth was similar but significantly higher than at -2C. With 0 storage, stolon growth declined after 8 days deacclimation; however, after 45 or 90 days of storage, significant reductions occurred after only 4 days deacclimation. Fully deacclimated as well as dormant field samples of 'Midiron', 'Tifdwarf', 'Tifgreen', 'Tifway' and 'Tufcote' taken in March and April, 1977, were subjected to -2, -4, and -6C. All cultivars survived -4C whether dormant or actively growing. 'Tifgreen' bermudagrass frozen while dormant and 'Tifgreen' and 'Tifdwarf' frozen while actively growing had high recuperative potentials during regrowth. Comparing these cultivars under field conditions showed best winter survival for 'Midiron', which was the only cultivar that survived with simulated traffic. Traffic imposed immediately prior to bermudagrass dormancy reduced spring recovery more than for traffic imposed during winter. / Master of Science

Examination of use of terminology using "carbohydrates" to describe reserve energy to plants. / Master of Science