UNT Theses and Dissertations - 111 Matching Results

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Biodiversity of Dragonflies and Damselflies (Odonata) of the South-Central Nearctic and Adjacent Neotropical Biotic Provinces

Description: The south-central United States serves as an important biogeographical link and dispersal corridor between Nearctic and Neotropical elements of western hemisphere odonate faunas. Its species are reasonably well known because of substantial collections, but there has been no concerted effort to document the extent of biodiversity and possible geographic affinities of dragonflies and damselflies of this region. The recent discoveries of Argia leonorae Garrison, Gomphus gonzalezi Dunkle and Erpetogomphus heterodon Garrison from southern and western Texas and northern Mexico suggest that Odonata species remain to be discovered in this area, particularly from far south Texas and northern Mexico. I have documented a total of 12,515 records of Odonata found in 408 counties within the south-central U.S. A total of 73 species of damselflies and 160 species of dragonflies was revealed in the region. The 233 (197 in Texas) Odonata species are distributed among 10 families and 66 genera. Illustrated family, generic, and species-level keys are provided. Since the beginning of this work in the Fall of 1993, one species has been added each to the Louisiana and Oklahoma faunas, and 12 species have been added, previously unreported from Texas, including four new to the U.S. The area of highest Odonata biodiversity overall (161 spp.) is in the Austroriparian biotic province. The greatest degree of faunal similarity between the south-central U.S. and other intra-continental regions was observed for the eastern (64%) United States. Diversity is a function of area, and as expected, the numbers of breeding birds and Odonata, in each contiguous U.S. state are positively correlated (r=0.376, n=33, p=0.031). There is, however, no strong correlation between land area and species diversity within the region, but those natural biotic provinces (Austroriparian, Texan, Balconian) where aquatic systems and topographic heterogeneity are the greatest provide a broader spectrum of potential Odonata habitats and ...
Date: May 1999
Creator: Abbott, John C.
Partner: UNT Libraries

Evaluation of Diet, Water, and Culture Size for Ceriodaphnia Dubia Laboratory Culturing

Description: Six reagent waters, eleven diets, and two culture sizes were evaluated for culturing C. dubia. Different filtration techniques were used to prepare the reagent waters. The eleven diets were comprised of two algae augmented with eight supplements. Reproduction and growth were assessed to discern differences among C. dubia raised in mass cultures and cultured in individual cups, during which, bacterial population densities, lipid, protein, and carbohydrate concentrations of the diets were measured. Results showed that a glass-distilled, carbon filtered, deionized reagent water and a Selenastrum capricornutum- Cerophyl® diet were optimum for culturing. Mass culturing supported the highest reproduction and growth, while no correlation was found between nutritional measurements and production.
Date: December 1992
Creator: Allen, Jerry D. (Jerry Dee)
Partner: UNT Libraries

Evaluation of a Constructed Wetland to Reduce Toxicity from Diazinon at the Pecan Creek Wastewater Treatment Plant, Denton, TX

Description: The City of Denton Pecan Creek Wastewater Treatment Facility has periodically failed effluent toxicity testing. A Toxicity Identification Evaluation has determined that Diazinon in the effluent is contributing to the observed toxicity. Chlorpyrifos is also implicated as a factor. The City of Denton constructed a half acre experimental wetland to remove Diazinon related toxicity. Results from spiking and microcosm experiments indicate that the wetland can reduce the Diazinon.
Date: May 1996
Creator: Baerenklau, Amy L. (Amy Lyn)
Partner: UNT Libraries

The Use of Similarity Indicies to Assess the Spatial Differences of the Phytoplankton Communities in Lake Ray Roberts, Texas

Description: A study of the phytoplankton communities of Lake Ray Roberts was conducted at three sampling sites on two sampling dates during the summer of 1995, assessing both community structure and chlorophyll a concentrations. Eight similarity indices were then used to characterize and compare the communities of these sites. Both community similarity and chlorophyll a concentrations were evaluated using a minimum detectable difference equation to determine the amount of change that must occur in these parameters in order to be deemed statistically significant. The Bray-Curtis Index was shown to be the most adequate index evaluated, and was subsequently used in conjunction with bootstrap analysis to determine the similarity between the three sampling sites.
Date: August 1996
Creator: Banks, Kenneth E. (Kenneth Edward)
Partner: UNT Libraries

Comparison of Aspartate Transcarbamoylase and Pyrimidine Salvage in Sporosarcina urea, Sprolactobacillus inulinus, Lactobacillus fermentum, and Micrococcus luteus

Description: The enzyme that catalyzes the committed step in pyrimidine biosynthesis, aspartate transcarbamoylase, has been compared in selected endospore-forming organisms and in morphologically similar control organisms. The ATCases and pyrimidine salvage from Sporosarcina ureae, Sporolactobacillus inulinus, Lactobacillus fermentum, and Micrococcus luteus were compared to those of Bacillus subtilis. While the ATCases from Sporosarcina ureae, Sporolactobacillus inulinus, and L. fermentum were found to exhibit characteristics to that of Bacillus with respect to molecular weight and kinetics, M. luteus ATCase was larger at approximately 480 kDa. Furthermore, pyrimidine salvage in Sporosarcina ureae and M. luteus was identical to those of B. subtilis, while pyrimidine salvage of Sporolactobacillus inulinus and L. fermentum resembled that of the pseudomonads.
Date: August 1994
Creator: Barron, Vincent N. (Vincent Neal)
Partner: UNT Libraries

Evaluating Fish Impingement and Entrainment at the Comanche Peak Steam Electric Station

Description: This study was designed to determine if impingement and entrainment by cooling water intake at the Comanche Peak Steam Electric Station have an adverse impact upon the Squaw Creek Reservoir fish population. The yearly impingement of fish was estimated to be 262,994 of 14 species. The threadfin shad (Dorosoma petenense) accounted for 96% of this total. Entrainment of eggs and larvae for a five month period was estimated to be 15,989,987 and 42,448,794 respectively. Two fish population studies were performed on Squaw Creek Reservoir to help assess impact. It was determined that the losses due to impingement and entrainment have no adverse impact upon the fish population of Squaw Creek Reservoir.
Date: May 1996
Creator: Bauml, George A. (George Arthur)
Partner: UNT Libraries

Pyrimidine Salvage Enzymes in Microorganisms: Labyrinths of Enzymatic Diversity

Description: Pyrimidine salvage pathways are essential to all cells. They provide a balance of RNA synthesis with the biosynthetic pathway in pyrimidine prototrophs and supply all the pyrimidine requirements in auxotrophs. While the pyrimidine biosynthetic pathway is found in almost all organisms and is nearly identical throughout nature, the salvage pathway often differs from species to species, with aspects of salvage seen in every organism. Thus significant taxonomic value may be ascribed to the salvage pathway. The pyrimidine salvage pathways were studied in 55 microorganisms. Nine different salvage motifs, grouped I-IX, were identified in this study based on the presence of different combinations of the following enzymes: cytidine deaminase (Cdd), cytosine deaminase (Cod), uridine phosphorylase (Udp), uracil phosphoribosyltransferase (Upp), uridine hydrolase (Udh), nucleoside hydrolase (Nuh), uridine/cytidine kinase (Udk), 5'-nucleotidase and CMP kinase (Cmk).
Date: December 1995
Creator: Beck, Debrah A. (Debrah Ann)
Partner: UNT Libraries

Responses of Selected Texas Fishes to Abiotic Factors, and an Evaluation of the Mechanisms Controlling Thermal Tolerance of the Sheepshead Minnow

Description: Low oxygen tolerances of ten fishes were estimated using an original nitrogen cascade design, and reciprocally transformed to express responses as ventilated volume necessary to satisfy minimal oxygen demand (L·mg O2^-1). Values ranged from 0.52 to 5.64 L·mg^-1 and were partitioned into three statistically distinct groups. Eight stream fishes showed moderately high tolerances reflecting metabolic adaptations associated with stream intermittency. Juvenile longear sunfish and two mollies comprised the second group. High tolerance of hypoxia may allow juvenile sunfish to avoid predation, and mollies to survive harsh environmental oxygen regimens. The sheepshead minnow was the most tolerant species of low oxygen, of those examined, explaining its presence in severely hypoxic environments.
Date: May 1994
Creator: Bennett, Wayne A. (Wayne Arden)
Partner: UNT Libraries

Documentation of Biodiversity Impacts (Including Cumulative Biodiversity Impacts) in Environmental Impact Statements

Description: In the United States, biodiversity impact assessment has historically received little attention. Responding in 1993, the Council on Environmental Quality (CEQ) released guidelines on incorporating biodiversity into environmental impact assessment under the National Environmental Policy Act of 1969. The objectives of the study here were to identify the level of documentation of biodiversity impact assessment in sample Environmental Impact Statements (EISs); identify whether in the years following the release of 1993 CEQ guidelines any significant changes have taken place in assessment of biodiversity; identify deficiencies, and if the need exists, formulate appropriate recommendations and approaches for addressing biodiversity in EISs. The study involved a systematic review of 30 EISs published since the release of CEQ guidelines, and five EISs published prior to it. The review involved answering a series of standard questions, which attempted to ascertain the level of biodiversity impacts included in each impact statement. Trends in approaches to biodiversity impact assessment were investigated and deficiencies summarized. The analysis resulted in a series of recommendations for improving the manner in which biodiversity impact assessment can be approached.
Date: August 1998
Creator: Bhatia, Sarika
Partner: UNT Libraries

The Effects of Long Term Modernate Ethanol Intake on Plasma Levels of ACTH, Beta Endorphin, and Corticosterone in Rats

Description: The effects of single injections and daily oral administration of ethanol on plasma levels of ACTH, beta endorphin, and corticosterone in response to cold stress were examined. The long-term experimental animals were given 0.25 ml of 28% ethanol or water orally once a day, five days a week, for fourteen months. Plasma levels of ACTH, beta endorphin, and corticosterone were lower in alcohol-treated rats as compared with water-treated rats when exposed to cold stress. The effects of a single injection of ethanol significantly elevated plasma levels of all three hormones. Mortality in sham-treated males was higher than ethanol-treated.
Date: December 1990
Creator: Breedlove, Kenneth
Partner: UNT Libraries

Advanced Molecular and Microbial Techniques: a Complete Laboratory Notebook

Description: The purpose of this project is to produce a complete and thorough notebook that may be used to supplement laboratory coursework. Its intent is to be used primarily by the students to aid them in understanding background information and the proper laboratory procedures involved in various types of experiments. The laboratory notebook is a summation of all the experiments and procedures used in the six-credit hour Advanced Microbial and Molecular Biology (BIOL 5160) course offered during the summer semester at the University of North Texas. This class is a team taught effort by Professors O'Donovan and Kunz. The course is constructed as an intensive practice exercise to teach the student about gene mutations, biosynthetic pathways, preparation and analysis of plasmid DNA, and many other topics included in the notebook.
Date: May 1998
Creator: Brito-Rodriquez, Carmen Lydia
Partner: UNT Libraries

Eutrophication Monitoring and Prediction

Description: Changes in trophic status are often related to increases or decreases in the allocthonous inputs of nutrients from changes in land use and management practices. Lake and reservoir managers are continually faced with the questions of what to monitor, how to monitor it, and how much change is necessary to be considered significant. This study is a compilation of four manuscripts, addressing one of these questions, using data from six reservoirs in Texas.
Date: December 1993
Creator: Cairns, Stefan H., 1949-
Partner: UNT Libraries

Heat Shock Proteins in Ascaris suum

Description: Ascaris suum were exposed to a number of stressors, including heavy metals and both high (40°C) and low (18°C) temperatures. The 70kD and 90kD heat shock proteins (HSPs) in the different A. suum tissues were analyzed by Western blot and quantitated by Macintosh Image Program.
Date: August 1995
Creator: Chao, Sheng-Hao
Partner: UNT Libraries

Biochemical Identification of Molecular Components Required for Cyanide Assimilation in Pseudomonas fluorescens NCIMB 11764

Description: Utilization of cyanide as a nutritional nitrogen source in P. fluorescens NCIMB 11764 was shown to involve a novel metabolic mechanism involving nonenzymatic neutralization outside of cells prior to further enzymatic oxidation within. Several cyanide degrading enzymes were produced by NCIMB 11764 in response to growth or exposure to cyanide, but only one of these cyanide, oxygenase (CNO), was shown to be physiologically required for assimilation of cyanide as a growth substrate.
Date: May 1998
Creator: Chen, Jui-Lin
Partner: UNT Libraries

Enzyme Assays Using Earthworms for Assessing Innate and Nonspecific Immunotoxicity of Xenobiotics

Description: Principal objectives of my research were to: (1) report for the first time that coelomocytes are able to reduce NBT dye and confirm the presence of lysozyme-like activity in earthworm; (2) develop a standard methodology for determination of NBT reduction and lysozyme-like activity in earthworms; (3) compare NBT reduction and lysozyme-like activity in earthworms with those of murine and human cells and fluids; and (4) demonstrate the sensitivity of earthworm NBT reduction and lysozyme-like activity as the assays using matrics in refuse-derived fuel fly ash (RDFF) and CuSO4.
Date: May 1992
Creator: Chen, Shing-Chong
Partner: UNT Libraries

Site Directed Mutagenesis Of Dienelactone Hydrolase

Description: The role of individual amino acid residues of the enzyme dienelactone hydrolase was investigated. Using the polymerase chain reaction (PCR), a 1.9 kbp clcD fragment was amplified and subcloned yielding a 821 bp BamHI to EcoRI clcD subclone in the plasmid pUC19. Site-specific mutants of dienelactone hydrolase were created using mismatched oligonucleotides to prime DNA synthesis. Specifically modified proteins from mutated clcD genes (Arg 81 to alanine, Tyr 85 to phenylalanine and Arg 206 to alanine), were encoded by the mutant clones. Enzyme assays showed that dienelactone hydrolase activity of the mutants Arg 81 and Arg 206 was totally abolished. The DLHase enzyme activity of mutant Tyr 85 is greatly decreased by approximately two thirds.
Date: December 1992
Creator: Chen, Wei, 1965-
Partner: UNT Libraries

Effects of Copper on Immune Responses of Largemouth Bass, Micropterus salmoides

Description: Copper exposures of 400 μg/L for 5,10 and 15 days resulted in no significant differences in antibody titers of largemouth bass, Micropterus salmoides injected with Aeromonas hydrophila compared to control-injected bass. Twenty days of exposure did significantly increase titers. The control group had significantly lower antibody titers than either control-injected or copper-exposed.
Date: August 1994
Creator: Connell, Patrice M. (Patrice Michelle)
Partner: UNT Libraries

Biology and Energetics of Tropisternus Lateralis Nimbatus (SAY) (Coleoptera: Hydrophilidae) in a Playa on the Southern High Plains of Texas and Aquatic Coleoptera Diversity from Seven Playas on the Southern High Plains of Texas

Description: A study of the biology of Tropisternus lateralis, a hydrophilid beetle, was conducted during the flood period of a single playa on the Southern High Plains of Texas from early June 1995 through early September 1995. Mechanism of colonization, tolerance/avoidance to drought, larval density, and secondary production were analyzed. T. lateralis colonized playas from surrounding aquatic habitats and avoided drought through aerial dispersion. Once in the playa, larval density increased over time. Secondary production was 1.31 g/m2/.25 yr. In addition, aquatic Coleoptera diversity was studied in seven playas on the Southern High Plains of Texas. A total of twenty three species were identified from the study region. Nine species not reported in playa literature were identified.
Date: December 1997
Creator: Cook, Robert E. (Robert Edward), 1969-
Partner: UNT Libraries

The Stress Protein Response of Pimephales promelas to Copper

Description: Organisms synthesize stress proteins in response to a variety of stressors. The 68/70-kDa proteins (synonymous to the 72/73-kDa proteins) have shown to be the most promising stress proteins, and have been proposed as a biomarker of general organismal stress. The 68/70-kDa proteins were used in an antigen/antibody based approach to determine the duration of the stress protein response of Pimephales promelas following an acute exposure to copper sulphate.
Date: May 1992
Creator: Covington, Sean M.
Partner: UNT Libraries

Development and Validation of a Ramping Treadmill Protocol for the On-Line Measurement of Four Aerobic Parameters

Description: Previously, Whipp et. al. (J. Appl. Physiol.: Respirat. Environ. Exerc. Physiol. 50(1):217-221, 1981) demonstrated the feasibility of determining four parameters of aerobic function, identified as maximum oxygen uptake (μVO_2), VO_2 at anaerobic threshold (θan), the time constant for oxygen uptake kinetics (rVO_2) and work efficiency (η), using a short duration ramped bicycle ergometer exercise test. Because of the importance of being able to measure these parameters on a variety of measurement instruments a short duration ramping treadmill protocol has been developed. The ability of this protocol to determine the four aerobic parameters has been validated against conventional methods. The results of this investigation indicate that μVO_2, θan, rVO_2 and, η may be obtained from a single, short-duration ramping treadmill test.
Date: May 1990
Creator: Cowell, Lynda L. (Lynda Lea)
Partner: UNT Libraries

Alterations in Human Baroreceptor Reflex Regulation of Blood Pressure Following 15 Days of Simulated Microgravity Exposure

Description: Prolonged exposure to microgravity is known to invoke physiological changes which predispose individuals to orthostatic intolerance upon readaptation to the earth's gravitational field. Attenuated baroreflex responsiveness has been implicated in contributing to this inability to withstand orthostatic stress. To test this hypothesis, eight individuals were exposed to 15 days of simulated microgravity exposure using the 6° head-down bed rest model. Prior to, and after the simulated microgravity exposure, the following were assessed: a) aortic baroreflex function; b) carotid baroreflex function; c) cardiopulmonary baroreflex function; and d) the degree of interaction between the cardiopulmonary and carotid baroreflexes.
Date: August 1993
Creator: Crandall, Craig G. (Craig Gerald)
Partner: UNT Libraries

Development of Cardiovascular Regulation in Embryos of the Domestic Fowl (Gallus Gallus), with a Partial Comparison to Embryos of the Desert Tortoise (Gopherus Agassizii)

Description: In adult vertebrates, cardiovascular regulation is accomplished by numerous systems with neural, hormonal and local components responsible for the majority of regulation. These regulatory components work in concert to maintain the essential function of blood perfusion to adult tissues. Given the essential nature of this function it is therefore surprising that the development of cardiovascular regulation during gestation is poorly understood. The majority of what is known is based on a single vertebrate model, the fetal lamb. The fetal lamb has been used in multiple studies due to the clear clinical applications and has been pivotal in understanding the onset of regulation in developing vertebrates. However, study on the fetal lamb is limited to the latter 40% of gestation and has the added complication of an in-utero developmental strategy. Therefore the primary focus of this dissertation was to characterize basic cardiovascular regulation in the chicken embryo to provided the needed information for it's use an alternative to the fetal lamb. Developing chicken embryos rely on both alpha and beta adrenergic tones to maintain normal heart rate and arterial blood pressure during incubation. However, on day 21, just prior to hatch, these animals lose both tones on arterial pressure suggesting the onset of adult regulation. Cholinergic tone, however, was absent throughout chicken development indicating that it must mature during the neonatal life. Adult cardiovascular reflexes become apparent late in chicken development with a clear baroreflex specifically operating initially on day. However, an adult response to changes in ambient gas tension was absent during incubation suggesting embryos possess unique regulatory systems that are absent in adult chickens. This mechanism is comprised entirely of adrenergic systems with no cholinergic action during change in ambient gas tension. Similar developmental patterns were determined in embryos of the desert tortoise suggesting fundamental differences between in-utero and ...
Date: August 1999
Creator: Crossley, Dane Alan
Partner: UNT Libraries