UNT Theses and Dissertations - 76 Matching Results

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Applications of GIS and Remote Sensing for the Characterization of Habitat for Threatened and Endangered Species

Description: Geographic Information Systems (GIS) and remote sensing technologies were used to identify and describe potential habitat for three species endemic to the Southwestern United States; the Golden-cheeked Warbler (Dendroica chrysoparia), the Black-capped Vireo (Vireo atricapillus), and the Texas kangaroo rat (Dipodomys elator). For each species, the computerized classification of digital satellite imagery was integrated with ancillary spatial information (e.g. soils, geology, and land use) to con… more
Date: December 1989
Creator: Shaw, Denice Marie, 1958-
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Partner: UNT Libraries
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Sediment Characteristics and Bioavailability of Sorbed Neutral Organic Compounds

Description: Several sediment characteristics were analyzed to determine their suitability for use as potential normalization factors for the bioavailability of neutral organic compounds sorbed to sediments. Percent organic carbon, cation exchange capacity and particle surface area were measured sediment characteristics that varied sufficiently to encompass the range in observed sediment toxicity. Laboratory sediment toxicity test data using fluoranthene suggest that there is no biologically significant cor… more
Date: December 1989
Creator: Suedel, Burton C. (Burton Craig)
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The Stoneflies (Plecoptera) of the Ozark and Ouachita Mountains

Description: Collections of stoneflies (Plecoptera) were made at 603 stream sites from Nov. 1983 - May 1988 in the Ozark-Ouachita Mountain region, in relation to physiographic and vegetational characteristics. Examination of approximately 9000 vials from these collections, supplemented with material from major museums and other collectors, revealed 88 stonefly species in 8 families and 24 genera. Pearson's measure of association (R) showed there was a significant association between species present and eac… more
Date: December 1989
Creator: Poulton, Barry C. (Barry Charles)
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Systematics of Coccidian Parasites (Apicomplexa) from Amphibians and Reptiles in Northcentral Texas

Description: Between February 1986 and October 1988, 863 amphibians and reptiles were collected in northcentral Texas and examined for coccidial parasites. Thirteen percent of amphibians <26% salamanders, 11% frogs and toads) and 28% of reptiles (54% turtles, 25% snakes) harbored 20 previously described and 16 new species of coccidia; overall prevalence of infection was 176/863 < 20%). Sixteen Ambvstoma texanum were infected with Eimeria ambystomae which represents new host and geographic locality records f… more
Date: December 1989
Creator: McAllister, Chris Thomas
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Toxicological Characterization of Trinity River Sediments

Description: Sediments in the Trinity River were chemically, physically and biologically characterized and assessed for toxicity. Laboratory bioassays were conducted to identify sediments which induced toxic responses in test organisms and to document these responses through time. Metal and organic contaminant concentrations in bottom sediments were measured. Relationships between these concentrations and biological responses observed in laboratory bioassays were determined. Toxicity identification / reduct… more
Date: December 1989
Creator: Hall, Jerry F. (Jerry Fowler)
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Validation of a Coupled Herbicide Fate and Target Plant Species Effects Model

Description: A series of experiments provided data to parameterize and validate a coupled herbicide fate and target plant species effects model. This simulation model is currently designed to predict responses of water hyacinth populations to treatments of the dimethylamine formulation of 2,4- dichloro-phenoxy acetic acid (2,4-D -DMA). Experiments investigated 1) the response of water hyacinth to varying exposures of 2,4-D (DMA); 2) the role of water hyacinth density and herbicide interception in treatment … more
Date: December 1989
Creator: Clifford, Philip A. (Philip Alan)
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Biological Control of the Red Imported Fire Ant by the Entomopathogenic Nematode, Steinernema Carpocapsae (Weiser)

Description: Field trials were conducted in 1988 to evaluate the effectiveness of Steinernema (=Neoaplectana) carpocapsae (Weiser) in controlling the fire ant. Infective juveniles (IJ) of the nematode were applied as drench on 235 and 422 mounds, respectively for 2-month summer and 6-week fall evaluation periods. In comparative trials, amidinohydrazone (Amdro) was applied to 249 (summer) and 65 (fall) active mounds, with 245 (summer) and 78 (fall) untreated active as controls. Nematode treatments resulted i… more
Date: August 1989
Creator: Morris, John R. (John Robert), 1949-
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Degradation of Phenolic Acids by Azotobacter Species Isolated from Sorghum Fields

Description: Sorghum plants excrete phenolic acids which reduce subsequent crop yields. These acids accumulate in field soil by combining with soil and clay particles to form stable complexes which remain until degraded by bacterial metabolism. The amount of phenolic acids in soil samples were obtained by gas chromatography measurements, while Azotobacter populations were obtained by plate counts in 40 sorghum field samples from Denton County, Texas. One can conclude that increasing the Azotobacter populati… more
Date: August 1989
Creator: Al-Hadhrami, Mohamed N. (Mohamed Nasser)
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Interactions between Carotid and Cardiopulmonary Baroreceptor Populations in Men with Varied Levels of Maximal Aerobic Power

Description: Reductions in baroreflex responsiveness have been thought to increase the prevalence of orthostatic hypotension in endurance trained athletes. To test this hypothesis, cardiovascular responses to orthostatic stress, cardiopulmonary and carotid baroreflex responsiveness, and the effect of cardiopulmonary receptor deactivation on carotid baroreflex responses were examined in 24 men categorized by maximal aerobic power (V02max) into one of three groups: high fit (HF, V0-2max=67.0±1.9 ml•kg^-1•min^… more
Date: August 1989
Creator: Pawelczyk, James A. (James Anthony)
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Partner: UNT Libraries
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Characterization of the OCT Plasmid-Encoded Mercury Resistance Genetic Locus in Pseudomonas putida

Description: A 17.1 Kb genetic element encoding for mercury resistance (OCT-Hg^r) was shown to translocate from its original location on the OCT plasmid to the resistance plasmid, RPl, in Pseudomonas putida. Analysis of RPl-Hg^r recombinant plasmids revealed that insertion of mercury resistance genes into RPl could occur at a variety of sites, with all recombinants having common EcoRI restriction fragments of 9.4, 3.8, 2.3, and 1.6 Kb, derived from the insertion. Hybridization analysis suggested the existen… more
Date: May 1989
Creator: Armbruster, Steven C. (Steven Christopher)
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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The Reproductive Consequences of Carriers of Methylenebisacrylamide-Induced Balanced Reciprocal Translocations in Mus Musculus

Description: N,N'-methylenebisacrylamide (MBA) was studied because of its effectiveness in inducing heritable translocations in germ cells of male mice. The health impact of translocations was studied through anatomical analysis of the progeny of semisterile translocation carriers. As expected, the semisterility of translocation carriers resulted primarily from embryonic death during periimplantation stages due to unbalanced chromosome sperm segregants. Among conceptuses that survived to mid- and late-gesta… more
Date: May 1989
Creator: Kile, Joanna L. (Joanna Le)
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Partner: UNT Libraries
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Suppression of Immune Functions by PCBs in the Earthworm Lumbricus terrestris

Description: This research is part of an effort to develop non-mammalian surrogate immunoessays with the earth worm Lumbricus terrestris to assess immunotoxic potential of xenobiotics to mammals. The objective was to determine if earthworm immunoessays, namely E- and S- rosette formation and phagocytosis, are sensitive to a known mammalian immunotoxin, the PCB Arclor 1254. Results are presented in terms of PCB exposure and tissue concentrations during uptake/depuration.
Date: May 1989
Creator: Rodriguez Grau, Jorge Luis
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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The Teratogenic Effects of Nocodazole and Acrylamide in Mus Musculus

Description: In two separate experiments, weight adjusted doses of nocodazole and acrylamide were injected intraperitoneally at various time intervals into twelve week old female mice. Within the nocodazole experiment, the doses were injected at varying time intervals before and after mating. On day seventeen of gestation, the female mice were sacrificed and their uterine contents examined. Nocodazole induced a significant increase in reproductive pathology per total implants when administered one hour aft… more
Date: May 1989
Creator: Oliva, Jean L. (Jean Louise)
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Response of Freshwater and Saltwater Toxicity Test Species to Calcium and Salinity Concentrations Encountered in Toxicity Tests

Description: The responses of freshwater (Daphnia magna. Pimephales promelas) and saltwater (Mysidopsis bahia. Cyprinodon variegatus) toxicity test species to elevated calcium concentrations and changing salinity conditions were investigated. The use of salinity as a criterion for selection between saltwater and freshwater test species was investigated by conducting both calcium and salinity toxicity tests. Salinity was determined to be an inappropriate criterion under conditions encountered in this study.
Date: 1989
Creator: Price, Edmund E., 1954-
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Partner: UNT Libraries
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Neuronal Survival After Dendrite Amputation: Investigation of Injury Current Blockage

Description: After dendrite transection, two primary injury current pathways may acount for cell death: (1) the lesion current at the site of injury and (2) the voltage sensitive calcium channels along the dendrite. Lesions were made with a laser microbeam in mouse spinal monolayer cell cultures. Polylysine was tried as a positively charged "molecular bandage" to block the lesion current. The calcium channel blockers, verapamil and nifedipine, were used to reduce the calcium channel current. Control toxicit… more
Date: December 1988
Creator: Shi, Ri Yi
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Adenylate Energy Charge Determinations of Soil Bacteria Grown in Soil Extract Medium

Description: The adenylate energy charge values of twenty bacteria isolated from soil and cultured in a medium consisting of soil and distilled water were determined by the luciferin-luciferase bioluminescense method. The purpose of this study was to examine the growth and energy charge values of these organisms in soil extract medium, and to determine what effect the addition of glucose has on their energy charge values. Three of the organisms employed in this study showed energy charge values similar to t… more
Date: August 1988
Creator: Rodriguez, Luis A. (Luis Antonio)
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Genetic Differentiation of the Geomys Pocket Gopher Complex of Texas

Description: Genetic variation was analyzed for populations of seven taxa comprising four cytotypes of the Geomys bursarius chromosome complex, including G. b. major, G. b. knoxjonesi, and the Edwards Plateau taxa, G. b. llanensis and G. b. texensis. Genetic relationships of the Edwards Plateau gophers with other taxa and between themselves were examined. Genetic similarity, number of fixed allelic differences, and ectoparasite distribution indicate the Edwards Plateau gophers are a distinct gene pool. Isol… more
Date: August 1988
Creator: Block, Scott B. (Scott Bishop)
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Genetic Variation in a Population of the Plains Woodrat Neotoma micropus

Description: Neotoma micropus from Jack County, Texas, were studied over a 9-month period. Loci from blood and saliva were used to determine genetic variation within the population. Deviations from Hardy-Weinberg equilibrium were found at one locus. The average temporal F over all seven loci was 0.040. Genetic structuring was subtle, fluctuated on a seasonal basis, and was due to differential migration or predation on genotypes. Heterozygotes tended to move more than homozygotes, and a greater proportion of… more
Date: August 1988
Creator: Stewart, John E. B. (John Edward Bakos)
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Life Histories Behavior and Space Partitioning in Selected Species of Western North American Plecoptera

Description: Five species of stoneflies (Zapada haysi, Plumiperla diversa, Taenionema pacificum, Isoperla petersoni, Arcynopteryx compacta) from the North Slope and Interior of Alaska were examined for seasonal patterns of emergence of adults and growth of nymphs. Generally growth was retarded during the winter in this region, and all species except I. petersoni completed growth prior to January. The life cycles of six stonefly species (Prostoia besametsa, Triznaka signata, Sweltsa coloradensis. Isoperla fu… more
Date: August 1988
Creator: Hassage, Rodney Lynn, 1947-
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Multivariate Analyses of Amphibian and Reptilian Distribution in Texas

Description: Presence-absence data for amphibians, chelonians, saurians, ophidians, and the terrestrial and aquatic ecological guilds of reptilians were analyzed using multivariate analyses. Geographically consistant distributional patterns were found for all faunal groupings. The correspondence between analyses of the different taxa and guilds was not perfect, but similarities were found. All analyses agreed on the presence of a distinctive region in east Texas. Most analyses also agreed on the presence of… more
Date: August 1988
Creator: Ward, Rocky
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Effects of Lysolecithin on Macrophages

Description: The effect of lysolecithin on the macrophage was studied using five macrophage function assays. The results of indicate that lyso lecithin is a macrophage activating agent which causes enhanced cell spreading, increased phagocytosis of sheep erythrocytes, heightened membrane activity in the presence of damaged autologous red blood cells, chemotaxis, and vigorous phagocytosis and intracellular killing of Staphylococcus albus.
Date: May 1988
Creator: Swee, Mei Hua
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Partner: UNT Libraries
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Niche Structure of an Anole Community in a Tropical Rain Forest within the Choco Region of Colombia

Description: Ten species of anoles at Bajo Calima within the Choco of Western Colombia separate into two principal microhabitat groups: forest species, and those inhabiting openings and edges. The ten anoles further separate according to ground and vegetation dwellers. There is a relation at Bajo Calima between the number of anole species and vegetational structural diversity. Anole diversity within a given macrohabitat is by perch microsite/microclimate heterogeneity. These are the two major ecological dim… more
Date: May 1988
Creator: Castro-Herrera, Fernando
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Physiological Responses of Myriophyllum spicatum to Time Varying Exposures of Diquat, 2,4-D and Copper

Description: The physiological responses of Myriophyllum spicatum to 2,4-D, diquat and copper were quantified using a plant tissue viability assay, and daily measures of dissolved oxygen and pH. Correlations of herbicide tissue residues to physiological response measures were determined and the relationship was used to develop exposure-response models. Diquat and copper had a greater effect on plant tissue viability than was observed for 2,4-D. Diquat produced greater reductions in dissolved oxygen concentr… more
Date: May 1988
Creator: Rocchio, Patricia Mary
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Production, Location, and Binding of Violacein in Janthinobacterium

Description: Violacein is a purple pigment typically produced by species of Chromobacterium and Janthinobacterium. A soil isolate, identified as Janthinobacterium, was studied. Maximal pigmentation occurred at 250C under aerobic conditions in the Keeble and Cross medium. Intracellular pigment was shown to be located in the cell membrane. Comparision of pigment production and growth curves indicated that violacein is synthesized in the cell and released into the environment possibly as a result of cell lysis… more
Date: May 1988
Creator: Lin, Ying-Chuan
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