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  Partner: UNT Libraries
 Degree Discipline: Biology
 Collection: UNT Theses and Dissertations
Establishing genetic and physiological baselines for the black-tailed prairie dog (Cynomys ludovicianus).

Establishing genetic and physiological baselines for the black-tailed prairie dog (Cynomys ludovicianus).

Date: May 2007
Creator: Biggs, Cindy Dawn
Description: The black-tailed prairie dog (Cynomys ludovicianus) has experienced dramatic declines over much of its historical range due to habitat loss, plague, poisonings, and shootings. Many populations now occur as isolated genetic relicts. A multiple locus genetic profile was obtained using microsatellite analyses of six polymorphic nucleotide repeats from 319 black-tailed prairie dogs collected from 16 colonies throughout the state of Texas. This assessment revealed that existing populations have sufficient variation at all six loci to verify the usefulness of this approach as a primary genetic tool in conservation and preservation. The data reveals regional-dependent frequency patterns as well as support for founder/bottleneck effects for several of the 16 sites. Although the prairie dog population in Texas as a whole may appear genetically diverse, considerable genetic divergence has already occurred among the subpopulations (FST = 0.164). Isolation by distance is supported by genic differentiation analysis (P < 0.001) and pairwise correlation analysis between genetic distance and geographic distance (P < 0.001). Prairie dogs from six (COC, LUBA, LUBC, LUBD, LUBE, and TAR) of the original 16 sites have been relocated or exterminated, or were in the process of being relocated. Results indicated the following colonies (COT, DAL, HOW, and HUD) are ...
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Eutrophic Levels of Different Areas of a Reservoir: A Comparative Study

Eutrophic Levels of Different Areas of a Reservoir: A Comparative Study

Date: August 1970
Creator: Hendricks, Albert C.
Description: It was the purpose of this investigation to attempt to demonstrate if differences in eutrophic levels existed among selected areas of Garza-Little Elm, and to demonstrate the role that sediments play in affecting eutrophication.
Contributing Partner: UNT Libraries
Eutrophication Monitoring and Prediction

Eutrophication Monitoring and Prediction

Date: December 1993
Creator: Cairns, Stefan H., 1949-
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.
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Evaluating Fish Impingement and Entrainment at the Comanche Peak Steam Electric Station

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

Date: May 1996
Creator: Bauml, George A. (George Arthur)
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.
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Evaluating the Habitat Requirements of the Golden Orb Mussel (Quadrula Aurea) for Conservation Purposes

Evaluating the Habitat Requirements of the Golden Orb Mussel (Quadrula Aurea) for Conservation Purposes

Date: May 2013
Creator: Hammontree, Sarah
Description: Many freshwater mussels are imperiled, due to a number of interrelated factors such as habitat alteration, degradation of water quality, and impoundments. The Golden Orb mussel (Quadrula aurea, I. Lea, 1859) is endemic to the state of Texas and is currently a candidate for the endangered species list, as the number of known populations has been declining in recent years. Little is currently known about Q. aurea aside from basic distribution data. This study is focused on evaluating a combination of macro-habitat and micro-habitat variables to determine their influence on the distribution and density of this species. Macro-habitat variables, including dominant land cover, surface geology, and soil erodibility factor, did not have a significant relationship with mussel distributions. The best model of micro-habitat variables that impacts the Q. aurea distributions is comprised of relative substrate stability (RSS) at moderate flows and current velocity at low flows. For all mussel species in this study, current velocity at low flows is the primary variable that influences distribution. Q. aurea are associated with habitats where larger sediment particles (large gravel and cobble) help to stabilize the substrate in areas with higher current velocities. An understanding of the preferred habitats for Q. aurea can ...
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Evaluation in Soil Moisture in Soil and Water Conservation Practices in Denton, Texas

Evaluation in Soil Moisture in Soil and Water Conservation Practices in Denton, Texas

Date: 1940
Creator: Rylander, Halley G.
Description: This investigation has attempted to show that soil and water conservation practices do increase the amount of soil moisture in five of Denton County, Texas soils: Denton clay, Durant clay, San Saba clay, Kirvin fine sandy loam, and Tabor fine sandy loam.
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Evaluation of a Constructed Wetland to Reduce Toxicity from Diazinon at the Pecan Creek Wastewater Treatment Plant, Denton, TX

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

Date: May 1996
Creator: Baerenklau, Amy L. (Amy Lyn)
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.
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Evaluation of City of Denton Sub-Watershed by Benthic Macroinvertebrate Field Experimental Approach

Evaluation of City of Denton Sub-Watershed by Benthic Macroinvertebrate Field Experimental Approach

Access: Use of this item is restricted to the UNT Community.
Date: August 2006
Creator: Mahato, Mahendra
Description: In this study, two different field experiments were designed to assess the relative influence of urbanization on benthic communities. During spring and summer, four urban and one reference sites from Denton County, Texas were selected for benthic macroinvertebrate evaluation. Statistically significant differences in colonized benthic macroinvertebrate taxa on artificial substrates were observed among the four urban sites and the reference site. Oligochaetes and chironomids were the dominant taxa at all sites. Identification of chironomid larvae at the subfamily and genus level to detect differences between sites had higher statistical power than the evaluation based on total chironomids. At the reference site, Caenis, Cladotanytarsus, Orthocladius, and Ceratopogonidae were the dominant taxa, while the urban sites were dominated by Dero, Physella, Ancylidae, Chironomus, Dicrotendipes, Glyptotendipes, Polypedilum, Pseudochironomus, Stenochironomus, and Tanytarsus. These differences may have been dependent upon differences in hydrologic regime and water quality between sites. Significant differences (ANOVA, p < 0.01) in water quality parameters (alkalinity, hardness, nitrates, phosphates, chlorides, sulfates, calcium, magnesium, potassium, and triazine) were found among water samples collected from the reference and urban sites. During the transfer period, most of the Ephemeroptera and Trichoptera taxa and a few other taxa disappeared from artificial substrates that were colonized ...
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An Evaluation of the United States Soil Conservation Service Program of Grassland Recovery on the Land Utilization Project in Wise county, Texas

An Evaluation of the United States Soil Conservation Service Program of Grassland Recovery on the Land Utilization Project in Wise county, Texas

Date: August 1952
Creator: Hyman, Ruel Richard
Description: This investigation was undertaken in order to evaluate the United States Soil Conservation Service program of grassland recovery on the land utilization project in Wise County, Texas.
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Evaluation of virulence in wild type and pyrimidine auxotrophs of  Pseudomonas aeruginosa using the eukaryotic model system  Caenorhabditis elegans.

Evaluation of virulence in wild type and pyrimidine auxotrophs of Pseudomonas aeruginosa using the eukaryotic model system Caenorhabditis elegans.

Access: Use of this item is restricted to the UNT Community.
Date: August 2004
Creator: Anvari, Sara
Description: The human opportunistic pathogen, Pseudomonas aeruginosa PAO1, has been shown to kill the nematode Caenorhabditis elegans. C. elegans has been a valuable model for the study of bacterial pathogenesis, and has reinforced the notion that common virulence and host defense mechanisms exist. Recently, the pyrimidine pathway was shown to regulate virulence levels. Therefore, mutations in the pyrimidine pathway of PAO1 showed decrease virulence in the nematode. When starving the nematode, bacterial resistance was also shown to increase. It was hypothesized that starvation induced the DAF pathway, which regulates the transcription of genes involved with the antibacterial defense mechanism. Further research will be conducted to test this theory by performing RNAi experiments for the genes functioning in the antibacterial defense mechanism.
Contributing Partner: UNT Libraries