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  Partner: UNT Libraries
 Degree Discipline: Biology
 Degree Level: Doctoral
 Collection: UNT Theses and Dissertations
Autonomic reflexes of the heart during acute myocardial ischemia

Autonomic reflexes of the heart during acute myocardial ischemia

Date: May 1993
Creator: Meintjes, André F. (André Francois)
Description: This study investigated whether acute myocardial ischemia of the anterior left ventricular wall induced an increase in cardiac sympathetic efferent nerve activity and thereby affected regional myocardial blood flow and contractile function.
Contributing Partner: UNT Libraries
Autoradiographic localization of carbachol-induced second messenger response in the rat spinal cord following inflammation.

Autoradiographic localization of carbachol-induced second messenger response in the rat spinal cord following inflammation.

Date: May 2002
Creator: Moore, Jack
Description: This study examined central mechanisms of persistent pain using an autoradiographic technique to localize phosphoinositide hydrolysis (PI) in the rat spinal cord dorsal horn. The lateral half of laminae I-II showed the highest levels of baseline PI turnover and carbachol-stimulated PI turnover in normal animals as well as after inflammation. Inflammation resulted in increased baseline PI turnover in this region of the ipsilateral (76%) and contralateral (65%) dorsal horns. Carbachol increased PI turnover in this region in normal rats (55%) and following inflammation (ipsilateral: 46%, contralateral: 45%). The absolute magnitudes of these increases were 1.85, 2.71, and 2.51 nCi/mg, respectively. The results of this study demonstrate the involvement of PI turnover in neural mechanisms of persistent pain, and provide evidence for the involvement of cholinergic systems in this process. Because spinal cholinergic systems have been reported to be anti-nociceptive, the present results appear to reflect an upregulation of anti-nociceptive activity in response to inflammation. Thus, the spinal cholinergic system may be a regulatory site within the anti-nociceptive pathway, and may provide an attractive target for the development of new therapeutic agents.
Contributing Partner: UNT Libraries
Benthic Macroinvertebrates of Temperate, Sub-Antarctic Streams: The Effects of Altitudinal Zoning and Temperature on the Phenology of Aquatic Insects Associated to the Robalo River, Navarino Island (55°S), Chile

Benthic Macroinvertebrates of Temperate, Sub-Antarctic Streams: The Effects of Altitudinal Zoning and Temperature on the Phenology of Aquatic Insects Associated to the Robalo River, Navarino Island (55°S), Chile

Date: December 2011
Creator: Contador Mejías, Tamara Andrea
Description: The Cape Horn Biosphere Reserve, within the remote Sub-Antarctic ecoregion is a reservoir of expressions of biological and cultural diversity. Although it is considered one of 24 wilderness areas remaining in the world, it is not free from local and global threats, such as invasive species, and climate change. Field biologists and philosophers associated to the Sub-Antarctic Biocultural Conservation Program and the Omora Ethnobotanical Park, have worked to describe the region’s biocultural diversity, linking ecological and philosophical research into education, ecotourism, and conservation, through a methodology called field environmental philosophy (FEP), which integrates ecological sciences and environmental ethics through a 4-step cycle consisting of: 1) interdisciplinary research; 2) composition of metaphors; 3) design of field activities with an ecological and ethical orientation; and 4) implementation of in situ conservation areas. In this context, the purposes of this dissertation were to: 1) provide a comprehensive review of publications regarding the conservation status of aquatic and terrestrial insects at a global scale and with an emphasis in southern South America; 2) study the distribution of benthic macroinvertebrates through the sharp altitudinal gradient of the Róbalo River watershed; 3) describe the life histories of Gigantodax sp (Simuliidae: Diptera) and Meridialaris chiloeense (Leptophlebiidae: Ephemeroptera) ...
Contributing Partner: UNT Libraries
Biochemical Identification of Molecular Components Required for Cyanide Assimilation in Pseudomonas fluorescens NCIMB 11764

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

Date: May 1998
Creator: Chen, Jui-Lin
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.
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Biodiversity of Caddisflies (Trichoptera) of the Interior Highlands of North America

Biodiversity of Caddisflies (Trichoptera) of the Interior Highlands of North America

Date: August 1994
Creator: Moulton, Stephen R. (Stephen Richard)
Description: Caddisflies (Trichoptera) were collected from over 500 different locations throughout the Interior Highlands (Ozark, Ouachita, Arbuckle, and Wichita Mountains) between March 1990 and March 1994. I systematically sampled representative lotic and lentic habitats in 131 natural watersheds that comprise the 17 different physiographic subregions of this area. From my examination of approximately 60,000 specimens, surveys of regional museum collections, and review of literature records, I document 229 species distributed in 16 families and 58 genera. Included in this total are 27 endemic species and 15 new regional records. Descriptions are provided for a species new to science (Cheumatopsyche robisoni), four larvae (Helicopsyche limnella, H. piroa, Marilia species A, Polycentropus crassicornis) and a female (Helicopsyche piroa). Hydropsyche reiseni Denning, previously known only from the Arbuckle Mountains, is reduced in synonymy with H. arinale Ross. Further, I provide illustrated family, generic, and selected species-level keys that reflect this regional biodiversity.
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Biogeography of Montane Mammals on the Colorado Plateau and Adjacent Regions

Biogeography of Montane Mammals on the Colorado Plateau and Adjacent Regions

Access: Use of this item is restricted to the UNT Community.
Date: May 2004
Creator: Carr, Carla B.
Description: This study identifies the biogeographic factors that structure small mammal communities on mountains of the Colorado Plateau and adjacent regions. Forty six isolated ranges were characterized across a 5-state study area encompassing the Colorado Plateau, including the central high plateaus of Utah and the Basin and Range Province (i.e. the Great Basin and mountains of Arizona and New Mexico). Presence/absence data of 25 montane mammal species were used to explore the interactions between historical and ecological processes affecting local and regional diversity patterns. Multivariate analyses, such as non-metric dimensional scaling, were used to explore factors which influence community composition. Results of these analyses revealed the Colorado River as a significant biogeographic barrier that affects montane mammal community structure. MtDNA cytochrome b sequence variation was analyzed among populations of the long-tailed vole, Microtus longicaudus, sampled from five interior ranges of the Colorado Plateau- Abajo, LaSal, Henry, and Chuska Mts., and Boulder Mountain of the Aquarius Plateau-and analyzed using traditional phylogenetic approaches (parsimony and likelihood) as well as nested clade analysis. Results support previous documentation of a major east-west phylogeographic break occurring between populations southeast of the Colorado River (eastern Arizona, Colorado, Wyoming and New Mexico) and all other western populations, which ...
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Biological and Toxicological Responses Resulting from Dechlorination of a Major Municipal Wastewater Treatment Plant Discharge to the Trinity River

Biological and Toxicological Responses Resulting from Dechlorination of a Major Municipal Wastewater Treatment Plant Discharge to the Trinity River

Date: August 1995
Creator: Guinn, Richard J. (Richard Joe)
Description: Federal regulations such as the Clean Water Act (P.L. 92-500), and its amendments, direct the Environment Protection Agency (EPA) to implement programs to control the releases of conventional pollutants and toxics into the waterways of the United States. The EPA began requiring treatment plants to conduct toxicity tests (biomonitoring) of their effluent discharges. To control toxicity caused by chlorination of wastewater discharges, the EPA also began requiring some treatment facilities to dechlorinate their wastewater before discharging. This research was funded by the EPA to document the changes that occurred in the Trinity River from the dechlorination of the effluent from Ft. Worth's Village Creek municipal wastewater treatment plant. The study occurred over a two year period beginning in August 1990. A wide variety of biological field assessments and toxicological assays were used to measure various responses. Seven river stations, covering approximately twenty river miles, and the treatment plant effluent were assessed. Two of the river stations were upstream from the treatment plant and used as reference sites. The remaining five river stations were downstream from the treatment plant, spread out over seventeen river miles. The study evaluated the impact of chlorination prior to dechlorination, which served as a baseline. Responses ...
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Biological Nitrogen Fixation in Two Southwestern Reservoirs

Biological Nitrogen Fixation in Two Southwestern Reservoirs

Date: August 1973
Creator: Lawley, Gary G.
Description: This investigation has determined the presence of biological nitrogen fixation in two reservoirs in the southwestern United States: Lake Arlington and Lake Ray Hubbard. Subsequent tests have gathered baseline data on the effects of various biological, chemical, and physical parameters on in situ nitrogen fixation in these reservoirs. Of specific importance is the relationship between nitrogen fixation arid occasional blooms of blue-green algae which produce such problems as testes and odors in these water-supply impoundments.
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Blood Pressure Regulation During Simulated Orthostatism Prior to and Following Endurance Exercise Training

Blood Pressure Regulation During Simulated Orthostatism Prior to and Following Endurance Exercise Training

Date: May 1992
Creator: Stevens, Glen Harold John
Description: Cardiovascular responses and tolerance to an orthostatic stress were examined in eight men before and after eight months of endurance exercise training. Following training, maximal oxygen consumption and blood volume were increased, and resting heart rate reduced. Orthostatic tolerance was reduced following training in all eight subjects. It was concluded that prolonged endurance training decreased orthostatic tolerance and this decrease in tolerance appeared associated with attenuated baroreflex sensitivity and alterations in autonomic balance secondary to an increased parasympathetic tone noted with training.
Contributing Partner: UNT Libraries
Carbon Flux in Reservoir Sediments

Carbon Flux in Reservoir Sediments

Date: May 1973
Creator: Newton, Charles Eugene
Description: The central objective of the study was to fractionate sedimenting organic materials according to their source (allochthonous or autochthonous) and ultimately to determine the degree of biodegradability of contributions from either source with particular reference to activities at the mud-water interface.
Contributing Partner: UNT Libraries