UNT Theses and Dissertations - 857 Matching Results

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The Population Genetic Structure of Quadrula aurea (Bivalvia: Unionidae), A Threatened Freshwater Mussel in Central Texas

Description: The anthropogenic alteration of riverine ecosystems has led to declines in the abundance and diversity of freshwater mussels (Bivalvia: Unionoida) worldwide. Central Texas is home to a diverse freshwater mussel fauna including three candidates for federal listing under the Endangered Species Act. Surveys conducted over the last few decades suggest many of the endemic freshwater mussel species in Texas exist in small isolated populations that may be vulnerable to the deleterious effects of genet… more
Date: May 2018
Creator: Mabe, Jeffrey A.
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Population Genetics, Karyology, and Morphology of Certain Species of the Peromyscus Truei Group

Description: The systematic relationship of two species of the Peromyscus truei group (P. truei and P. difficilis) was analysed through the application of starch gel electrophoresis, numerical taxonomy, and chromosomal techiques. Of 20 loci examined, 11 were monomorphic in all populations, two exhibited variation in only two populations, and seven loci were polymorphic in two or more populations. The mean number of polymorphic loci per population was 0.186, the mean number of polymorphic loci per individual… more
Date: May 1976
Creator: Hart, Billy Joe
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Population Studies of Ulmus Crassifolia in Flood-Plain Forests of Denton County, Texas

Description: The problem with which this investigation was concerned was the comparison of cedar elm populations in different stands along creeks in Denton County, Texas, and the relationship of certain population parameters to various substrates present at stand sites, Parameters investigated eluded average basal area, basal-area density, transect-segment density, intertree distance, lateral distance, frequency, diameter breast-high, diameter breast-high size-class distribution, and immature-tree density. … more
Date: August 1974
Creator: Koch, Linda S.
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Possible uses of North Texas Plants and Animals in Elementary Science

Description: This thesis aimed to study plants and animals of North Texas which are adaptable for use in elementary science. In this study, 15 groups of plants and animals were selected as representative ones and among other benefits, each group of organisms was examined for its contributions to a limited understanding of bilogical principles.
Date: May 1937
Creator: Millican, Addie
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Predicting the Site-Specific Bioavailability of Zinc Using the Indicator Species Procedure: A Case Study

Description: National Water Quality Criteria intended to protect aquatic life and their uses from the adverse effects of pollutants may not be appropriate due to site-specific factors that alter chemical bioavailability. The Indicator Species Procedure may be used to derive site-specific criteria in order to account for differences in site-specific bioavailability. This procedure was implemented using zinc for three chemically different site (river) waters. The purpose of this study was to quantify the bioa… more
Date: May 1987
Creator: Parkerton, Thomas F.
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Prediction of Post Mortem Interval from Degradation of Endogenous Nucleotides in Human Subjects

Description: High Performance Liguid Chromatography was used to measure degradation of nucleotides in human cadavers for the purpose of prediction of post mortem interval. Endogenous nucleotides were extracted from integumentary tissue of six(6) human cadavers using six percent(6%) tricholoacetic acid. Linear regression statistical techniques were used to determine linearity of degradation of various nucleotide pools.
Date: April 1993
Creator: Williams, John Burgess
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A Preliminary Report on the Effect of Roentgen Rays on the Formed Elements of Avian Blood

Description: This problem consists primarily in determining the numerical value of the leukocytes after different amounts of roentgen rays had been applied to the subjects. The Atomic Energy Commission set up a problem concerning the effects of roentgen rays on the fertility in chickens, and grants were given to two institutions to study this. The blood work in this paper was an off-shoot from one of these five fertility grants.
Date: August 1954
Creator: Berger, Gillett
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Pressure-Flow Relationships in the Isolated Cerebral Circulation of the Dog

Description: The purpose of this investigation is to determine the pressure-flow relationships in the isolated canine cerebral vascular bed. These relationships in vessels which supply an organ surrounded by bone are theoretically influenced by limiting factors which are not present in those vessels surrounded by soft tissue. An evaluation of the extent of these limitations is essential to thorough understanding of the dynamics of the cerebral vascular bed.
Date: June 1962
Creator: Alexander, William Carter
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Primary Cilia in the Oligodendrocyte Lineage

Description: oligodendrocytes migrate from the corpus callosum into the overlying cortex. The incidence of cilia did not change markedly across age groups, and did not vary consistently with the number of processes per cell, which was used as an indication of the maturation stage of OPCs and young OLs. The mean percent of Olig1 immunopositive (Olig1+) cells having cilia across ages was 33.1% + 16.5%, with all ages combined. In O4+ cells of these mice, 56.7 + 3.6% had primary cilia. If it is the case that ad… more
Date: May 2013
Creator: Hao, Yung-Chia
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Primary Productivity and Nutrient Relationships in Garza-Little Elm Reservoir

Description: A large, multi-basin, reservoir (Garza-Little Elm Reservoir) in north central Texas was studied to determine the relative effects of various parameters on primary productivity. The basins were impounded several years apart,thus allowing the influence of age on water chemistry and biota to be considered. Another principal influence on water quality was secondary sewage effluent that entered one basin from a nearby source.
Date: May 1973
Creator: Smith, Jerry Allen
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Probabilistic Modeling for Whole Metagenome Profiling

Description: To address the shortcomings in existing Markov model implementations in handling large amount of metagenomic data with comparable or better accuracy in classification, we developed a new algorithm based on pseudo-count supplemented standard Markov model (SMM), which leverages the power of higher order models to more robustly classify reads at different taxonomic levels. Assessment on simulated metagenomic datasets demonstrated that overall SMM was more accurate in classifying reads to their res… more
Date: May 2021
Creator: Burks, David
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Production and Characterization of a Novel Extracellular Polysaccharide Produced by Paenibacillus velaei, Sp. Nov

Description: Paenibacillus velaei, sp. nov. is a soil bacterium capable of producing an unusually large amount of exopolysaccharide (EPS). The EPS contains glucose, mannose, galactose and fucose in a molar ratio of 4:2:1:1. The molecular weight of the EPS is higher than 2x106. The viscosity of 1% EPS is 1300 cP when measured at a shear rate of 1 sec-1. Physiological parameters for optimal production of the EPS were studied and it was found that 1.4 g dry weight per 1 l of medium was produced when the bacter… more
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Date: August 2000
Creator: Sukplang, Patamaporn
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Production and Energy Metabolism in Three Benthic Insect Populations in a Small North Central Texas Pond

Description: Annual energy budgets of dominant benthic macro-invertebrates were examined during November 1973 to October 1974 from the benthos of a small pond ecosystem in north-central Texas. Estimates of annual secondary production (Hynes and Coleman 1968) were Procladius s. (Diptera, Chironimidae), 2.4 g m^-2 y^-1 (13 kcal m^-2 y^-1 ); Tendipes decorus (Diptera, Chironomidae), 6.0 g m^-2 y^-1 (40 kcal m^-2 y^-1 ); Brachycercus sp. (Ephemeroptera, Caenidae), 1.9 g m^-2 y^-1 (11 kcal m^-2 y^-1). Energy met… more
Date: May 1978
Creator: Benson, Daniel J.
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Production and Optimization of Para-Hydroxybenzoic Acid (pHBA) in Algae Using Metabolic Engineering and Genomics Approaches

Description: Microalgae being photosynthetic and having quick growth cycles can prove to be excellent candidates as biofactories for the production of aromatic compounds like para-hydroxybenzoic acid (pHBA) that act as a monomer in liquid crystal polymers. We developed transgenic lines of the model alga Chlamydomonas reinhardtii by performing nuclear transformation using electroporation. The transgenic cell lines expressed the ubiC gene that utilized chorismate from the shikimate pathway as a substrate to p… more
Date: December 2021
Creator: Saxena, Garima Girish
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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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The Production of Fragile Cysts by an Aberrant Strain of Azotobacter Chroococcum Isolated from Soil

Description: The purpose of this study is to determine if a strain of Azotobacter chroococcum isolated from the soil in northern Louisiana produces cysts which are as resistant to deleterious agents as those produced by previously reported strains os Azotobacter.
Date: May 1969
Creator: Cagle, Gerald D.
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Properties of Normal Rat Kidney Cells Transformed by a Temperature-Sensitive Mutant (LA31) of Rous Sarcoma Virus

Description: The basis of this investigation is to characterize growth property differences in normal versus virally transformed cells. Using a temperature-sensitive mutant of Rous sarcoma virus, the cells' transformation state is regulated by the growth temperature; at 33°C the cells are transformed, while at 39°C the cells have normal characteristics. The morphology of NRK cells is elongated and fibroblastic; when transformed the cells are rounded. Normal cells grow to a monolayer and stop, while transfor… more
Date: August 1983
Creator: Connolly, John R. (John Robert)
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Protein Profiles of Azotobacter Vinelandii During the Encystment Process

Description: Azotobacter vinelandii 12837 was grown in Burk's glucose media and transferred onto Burk's n-butanol agar plates to allow for the formation of cysts. The patterns of the vegetative cell proteins were compared for each successive day of cyst formation, using the polyacrylamide gel isoelectric focusing technique. The findings revealed that, as the cysts developed to maturity, definite changes occurred in the protein constitution, indicative of the biochemical and physiological changes which cells… more
Date: August 1977
Creator: Butler, Mark A.
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Purification and Characterization of Aldolase From Ambystoma Tigrinum

Description: The muscle aldolase from Ambystoma tigrinum has been purified 73-fold to a final specific activity of 13.2 units per mg. The purified enzyme appeared to be homogenous by ultracentrifugation and electrophoretic criteria. A molecular weight of 159,000 + 1000 was determined by gel filtration on Sephadex G-200 and high speed sedimentation equilibrium ultracentrifugation. The enzyme migrated identically with rabbit muscle aldolase when subjected to sodium dodecyl sulfate polyacrylamide gel electroph… more
Date: December 1975
Creator: Woolever, Dorothy J.
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