UNT Theses and Dissertations - 857 Matching Results

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Key Factors Influencing Retention Rates among Historically Underrepresented Student Groups in STEM Fields

Description: The aim of the study was to identify the factors that have an influence on the completion rates of undergraduate students in the fields of science, technology, engineering and mathematics (STEM). Using Tinto's retention rate theory as the theoretical foundation, data were collected from freshman who were enrolled in the years 2005 to 2008. Results showed gender and first-generation status were significant predictors of STEM completion and time taken to complete the degree. Institutional bias pl… more
Date: December 2018
Creator: Premraj, Divya
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Syllabus Outline for Genetics Lecture and Laboratory

Description: This work is intended to be used as a teaching tool in conjunction with the text cited. It is written in outline format, highlighting the major concepts of each pertinent chapter. In this format, the concepts can be expanded upon at the discretion of the instructor. This work is to be used as a guide for lecture. The basic concepts contained in the outline are in such a format as to be able to work in more information regarding the subject matter if needed. The instructor can work from this out… more
Date: December 1999
Creator: Preston, E. Lynn
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Responses of Fishes to a Low pH Environment

Description: Data were collected from natural and introduced fishes present in Ferndale Lake, a small (120 ha) sport fishing reservoir in Camp County, east Texas. Levels of pH measured in the lake during the study period ranged from 3.5 to 5.3. Monthly field surveys and experimental manipulations were designed to evaluate quantitatively the signs of stress at various biological levels. Lethal limits to low pH were quantified for largemouth bass (Micropterus salmoides) and bluegill (Lepomis macrochirus) to b… more
Date: August 1981
Creator: Prete, Philip J. (Philip John)
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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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Metabolism of Hydrocortisone by X-Irradiated Rat Liver Tissue as Determined by the Porter-Silber Chromagen Method

Description: The present study may be considered endocrinological and radiobiological in nature. The endocrinology phase was concerned with studying the changes in endocrine function following the application of a stress agent. X-irradiation was chosen as the stressor in order to determine any difference in effect of this stressor from others which have been studied, e. g. heat, cold, metabolic poisons. Liver slices taken from rats at various time intervals following whole body X-irradiation were tested for… more
Date: August 1959
Creator: Pryor, Nan Webb
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Studies on Zebrafish Thrombocyte Function

Description: Thrombocytes are important players in hemostasis. There is still much to be explored regarding the molecular basis of the thrombocyte function. In our previous microarray analysis data, we found IFT122 (an intraflagellar transport protein known to be involved in cilia formation) transcripts in zebrafish thrombocytes. Given recent discoveries of non-ciliary roles for IFTs, we examined the possibility that IFT122 affects thrombocyte function. We studied the role of IFT122 in thrombocyte function.… more
Date: May 2017
Creator: Pulipakkam Radhakrishnan, Uvaraj
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Percolation, Capillarity and Chresard of Representative Denton County Soils

Description: This paper deals with a study of the chresard, percolation, and capillarity of twenty representative Denton County soils. The group of soils chosen vary greatly in texture thus affording excellent material for comparative studies of edaphic factors based upon this property.
Date: August 1938
Creator: Quimby, Don Clarence
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Microbiological Treatment of Wastewater from a Wood-Preserving Plant

Description: This research investigates interacting biological, chemical, and physical factors affecting the efficiency of microbiological wastewater treatment at the W. J. Smith Wood- Preserving Company in Denison, Texas. The treatment process consisted of collecting exhaust boiler water containing unidentified boiler treatment compounds, steam condensate contaminated with preservatives and wood extracts, plant process waters, and rainfall runoff from plant grounds. With a 5-minute residence time, wastewat… more
Date: August 1974
Creator: Ralston, James R.
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Effects of X-irradiation on Potassium Flux in Isolated Nerves

Description: The purpose of this study, therefore, was threefold in nature: (1) to determine the effects of x-irradiation on the influx and efflux of potassium in compound nerve fibers (2) to attempt to relate the radiation-induced changes in electrical activity with potassium flux and (3) to use the information obtained to gain insight into the possible cellular site (s) of radiation insult to compound nerves.
Date: August 1966
Creator: Ramsey, Christian Norman
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The Ecology and Paleobiogeography of Freshwater Mussels (Family: Unionidae) from Selected River Basins in Texas

Description: This dissertation has two overall objectives: first, to demonstrate the utility of paleozoological data for ongoing and future mussel-conservation efforts in Texas and second, to evaluate whether simple measures of habitat (e.g., water depth, velocity and particle size) are important for demonstrating the within-habitat spatial separation of mussels. Although these topics may seem disparate, both are important for increasing our understanding of unionid ecology and biogeography. Chapters 1 th… more
Date: May 2011
Creator: Randklev, Charles R.
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Relationship of Certain Fungi to Azotobacter in Nitrogen-Free Media

Description: Azotobacter and various fungi were grown together in nitrogen-free media. Maximal fungal growth in the medium used was possible only at the expense of Azotobacter cells and growth was always accompanied by acid production. When the medium reached a pH of 2, the bacterial cells were aggregated on fungal hyphae and the culture fluid appeared to be free of Azotobacter. Aspergillus niger grew well at the expense of viable bacteria and other fungi grew well on heat-killed cells of A. vinelandii. Mem… more
Date: August 1976
Creator: Ray, Manfred G.
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Colchicine Reversibly Inhibits Electrical Activity in Arthropod Mechanoreceptors

Description: Dendrites of cockroach tibial spine mechanoreceptors contain hundreds of free microtubules, which may have some relation to the generation of electrical activity. Deflection of a spine produces a train of action potentials. Continuous perfusion over a period of 4 hours results in no response decrement. Perfusion with 10mM colchicine reversibly inhibits the response within 5-7 minutes. Irreversible inhibition is produced by perfusion with 1mM vinblastine sulfate in perfusion solution containing … more
Date: August 1977
Creator: Reagan, Paul D.
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Effects of High Altitude Exposure on Capillary Permeability

Description: Observations of decreases in plasma volume, shifts in plasma and lymph protein concentrations, and increases in capillary permeability at high altitude have been reported in the literature by several investigators. This investigation was begun in an attempt to elucidate the possible significance of these phenomena in future space exploration, and because of the lack of knowledge concerning the underlying mechanisms. The purpose of this investigation was to determine the effects of exposure to … more
Date: December 1971
Creator: Reaves, Troy Albert
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The Immune Response of Guinea Pigs as Influenced by Hypobaric Pressure and Normoxic Environment (Part I); Membrane Filter-Fluorescent-Antibody Method for Detection and Enumeration of Bacteria in Water (Part II)

Description: In this work experimental design and tests were established to determine whether antibody production in guinea pigs injected with a bacterial antigen is Influenced by the environment of simulated high altitude with normoxic conditions. Hematological and electrophoretic studies were simultaneously run with the antibody determinations as a check on related responses of the animals.
Date: August 1969
Creator: Reeder, Dennis James
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Flow-Recruitment Relationships of Smallmouth Buffalo (Ictiobus bubalus) in Three Texas River Basins

Description: This project focused on the relationship between instream flows and smallmouth buffalo (Ictiobus bubalus) recruitment in the Gulf Coastal Plain of Texas. The flow regime is the dominant factor in lotic systems and, consequently, the relationship between instream flows, including impacts to natural flow regimes, and life-history is a subject of growing interest. Smallmouth buffalo is a good model to investigate the relationship between river flows and variable interannual recruitment success of … more
Date: August 2021
Creator: Reeves, Cole Griffin
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Fate of Endothall in Aquatic Environments

Description: Hazard assessment of pesticides in aquatic environments requires accurate predictions of persistence and compartmentalization. A strategy for developing confidence in predictive fate models, such as the Exposure Analysis Modeling System (EXAMS) and the Simplified Lake and Stream Analysis model (SLSA), is to test the models using carefully chosen chemicals in semi-controlled and field situations. An objective of this approach would be to isolate the variability in a particular fate process and t… more
Date: December 1984
Creator: Reinert, Kevin H. (Kevin Howard)
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The Role of Cysteinyl Leukotriene Receptor 2 in Thrombocyte Aggregation

Description: Cysteinyl leukotriene receptor 2, a G-protein coupled receptor known to be expressed and functional on human platelets. However, it seems that upon ligand activation the cysteinyl leukotriene receptor 2 activates a variety of signaling pathways in multiple cell types among different species. Previously, a former laboratory member Vrinda Kulkarni found cysteinyl leukotriene receptor 2 to be expressed on the surface of adult zebrafish thrombocytes. In this work I studied the characteristics of ag… more
Date: December 2015
Creator: Reyna, Julianna
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Thermal Stress During Pre-Incubation Induces Subsequent Developmental Plasticity in Northern Bobwhites

Description: Northern bobwhite populations have declined concurrent with global warming. The focal period of this study was the 12-d pre-incubation period, when bobwhite eggs remain in the nest without the thermal protection of the incubating parent. This study first established the storage and thermal limits of bobwhite eggs, then investigated how global warming may impact oviparous embryos and how bobwhite embryos react to acute and chronic doses of simulated drought temperatures during pre-incubation. … more
Date: August 2010
Creator: Reyna, Kelly Shane
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