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Selection and Use of Aquatic Vegetation by Migratory Waterfowl in North Central Texas

Description: Assessment of aquatic plant selection by waterfowl has been conducted during the winters of 1997-2000 on 49 0.2-0.79 ha research ponds in north central Texas. Ponds were categorized by dominant plant species into eight habitat types. Census with waterfowl species identification were performed to investigate impacts of aquatic vegetation and water depth on waterfowl. Eighteen waterfowl species were observed. Peak migration occurred in late December/early January. Mixed native ponds and mixed nat… more
Date: May 2001
Creator: Smith, JoEtta Kaye
Item Type: Refine your search to only Thesis or Dissertation
open access

Portrait of Your Stream: Development and Assessment of a Stream Ecology Program for Middle-School Student

Description: Portrait of Your Stream (POYS) is a stream ecology and student action program designed for use with middle-school students. The program is correlated with learning cycle pedagogical methods emphasizing student-centered lessons and activities in both classroom and outdoor settings. Implementation of a pilot program in the Fall semester of 1999 was used to collect formal and informal responses and data from students and teachers. Data included changes in student knowledge, skills and attitudes an… more
Date: May 2001
Creator: Swirczynski, Brenda J.
Item Type: Refine your search to only Thesis or Dissertation

Development of a Procedure to Evaluate Groundwater Quality and Potential Sources of Contamination in the East Texas Basin

Description: This study contributes a procedure, based on data analysis and geostatistical methods, to evaluate the distribution of chemical ratios and differentiate natural and anthropogenic contaminant sources of groundwater quality in the East Texas Basin. Four aquifers were studied, Sparta, Queen City, Carrizo and Wilcox. In this study, Carrizo- Wilcox is considered as one aquifer, and Sparta-Queen City as another. These aquifers were divided into depth categories, 0-150 feet for Sparta-Queen City and 3… more
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Date: May 2001
Creator: Alderman, John H.
Item Type: Refine your search to only Thesis or Dissertation
open access

Age-Dependent Effects Of Chronic GABAA Receptor Blockade In Barrel Cortex

Description: GABAA receptor binding is transiently increased in rat whisker barrels during the second postnatal week, at a time when neurons in the developing rat cortex are vulnerable to excitotoxic effects. To test whether these GABAA receptors might serve to protect neurons from excessive excitatory input, polymer implants containing the GABAA receptor antagonist bicuculline were placed over barrel cortex for a 4-day period in young (postnatal days 8 - 12) and adult rats. In the cortex of young, but no… more
Date: May 2001
Creator: Gargan, Lynn
Item Type: Refine your search to only Thesis or Dissertation

Riparian Forest Width and the Avian Community in a Greenbelt Corridor Setting

Description: The forest avian community of the Ray Roberts Greenbelt (Denton Co., Texas) was characterized for two years using point count station sampling, from fall 1998 to summer 2000. Richness data for both breeding seasons were correlated with two-spatial metrics: width of the riparian forest and distance to the nearest edge. There were significant correlations between forest interior species richness and both spatial metrics, for both breeding seasons. Based on these data, a minimum riparian forest wi… more
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Date: May 2001
Creator: Hoffman, Karl W.
Item Type: Refine your search to only Thesis or Dissertation
open access

Correspondence Between Aquatic Ecoregions and the Distribution of Fish Communities of Eastern Oklahoma

Description: I assessed fish community data collected by the Oklahoma Conservation Commission from 82 minimally impaired wadeable reference streams in eastern Oklahoma to determine whether existing aquatic ecoregions provide the best framework for spatial classification for the development of biological assessment methods and biocriteria. I used indirect ordination and classification to identify groups of sites that support similar fish communities. Although correspondence was observed between fis… more
Date: May 2001
Creator: Howell, Charles E.
Item Type: Refine your search to only Thesis or Dissertation

The Developmental Physiology of the Zebrafish: Influence of Environment and Cardiovascular Attributes

Description: Temperature effects on the development of the zebrafish embryos and larvae and adults were examined. It was found that the earlier in development a temperature change was performed on an embryo, the more significant the change in survival and/or subsequent development. Thus, viable temperature ranges for zebrafish widened significantly as development proceeded. Adults reared and bred at 25oC produced embryos that were significantly more successful at the lower range of rearing temperatures comp… more
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Date: August 2001
Creator: Bagatto, Brian
Item Type: Refine your search to only Thesis or Dissertation

Comparison of GPS Point Selection Methods for GIS Area Measurement of Small Jurisdictional Wetlands

Description: U.S. Army Corps of Engineers (USACE) regulates fill of jurisdictional waters of the United States including wetlands. Recent USACE regulations set a threshold of impacts to wetlands at one-half acre. Impact area can be determined by Global Positioning System (GPS) measurement of wetland boundary and Geographic Information System (GIS) calculation of impact area. GPS point selection methods include (1) equal time interval, (2) transect and (3) intuition. Four two-acre shapes were measured with e… more
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Date: August 2001
Creator: Shelton, Michael
Item Type: Refine your search to only Thesis or Dissertation
open access

A Novel Mechanism for Site-Directed Mutagenesis of Large Catabolic Plasmids Using Natural Transformation

Description: Natural transformation is the process by which cells take up DNA from the surrounding medium under physiological conditions, altering the genotype in a heritable fashion. This occurs without chemical or physical treatment of the cells. Certain Acinetobacter strains exhibit a strong tendency to incorporate homologous DNA into their chromosomes by natural transformation. Transformation in Acinetobacter exhibits several unique properties that indicate this system's superiority as a model for tra… more
Date: August 2001
Creator: Williamson, Phillip C.
Item Type: Refine your search to only Thesis or Dissertation
open access

Spatial and Temporal Patterns of Areal and Volumetric Phytoplankton Productivity of Lake Texoma

Description: Phytoplankton productivity of Lake Texoma was measured for one year from August 1999 to August 2000 for four stations, using the oxygen change method and laboratory incubation. Mean values of the photosynthetic parameters, PBmax and alphaB ranged from 4.86 to 46.39 mg O2.mg Chl-1.hr-1 for PBmax and 20.06 to 98.96 mg O2.mg Chl-1.E-1.m2 for alphaB. These values were in the range to be expected for a highly turbid, temperate reservoir. Estimated gross annual areal productivity ranged from 594 g… more
Date: August 2001
Creator: Baugher, Tessy
Item Type: Refine your search to only Thesis or Dissertation

An examination of the riparian bottomland forest in north central Texas through ecology, history, field study, and computer simulation

Description: This paper explores the characterization of a riparian bottomland forest in north central Texas in two ways: field study, and computer simulation with the model ZELIG. First, context is provided in Chapter One with a brief description of a southern bottomland forest, the ecological services it provides, and a history of bottomland forests in Texas from the nineteenth century to the present. A report on a characterization study of the Lake Ray Roberts Greenbelt forest comprises Chapter Two. The … more
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Date: August 2001
Creator: Holcomb, Sheralyn S.
Item Type: Refine your search to only Thesis or Dissertation
open access

Plastidial carbonic anhydrase in cotton (Gossypium hirsutum L.): characterization, expression, and role in lipid biosynthesis

Description: Recently, plastidial carbonic anhydrase (CA, EC 4.2.1.1) cDNA clones encoding functional CA enzymes were isolated from a nonphotosynthetic cotton tissue. The role of CA in photosynthetic tissues have been well characterized, however there is almost no information for the role of CA in nonphotosynthetic tissues. A survey of relative CA transcript abundance and enzyme activity in different cotton organs revealed that there was substantial CA expression in cotyledons of seedlings and embryos, both… more
Date: August 2001
Creator: Hoang, Chau V.
Item Type: Refine your search to only Thesis or Dissertation
open access

Palmitoyl-acyl Carrier Protein Thioesterase in Cotton (Gossypium hirsutum L.): Biochemical and Molecular Characterization of a Major Mechanism for the Regulation of Palmitic Acid Content

Description: The relatively high level of palmitic acid (22 mol%) in cottonseeds may be due in part to the activity of a palmitoyl-acyl carrier protein (ACP) thioesterase (PATE). In embryo extracts, PATE activity was highest at the maximum rate of reserve accumulation (oil and protein). The cotton FatB mRNA transcript abundance also peaked during this developmental stage, paralleling the profiles of PATE enzyme activity and seed oil accumulation. A cotton FatB cDNA clone was isolated by screening a cDNA lib… more
Date: August 2001
Creator: Huynh, Tu T
Item Type: Refine your search to only Thesis or Dissertation
open access

The regulatory roles of PyrR and Crc in pyrimidine metabolism in Pseudomonas aeruginosa

Description: The regulatory gene for pyrimidine biosynthesis has been identified and designated pyrR. The pyrR gene product was purified to homogeneity and found to have a monomeric molecular mass of 19 kDa. The pyrR gene is located directly upstream of the pyrBC' genes in the pyrRBC' operon. Insertional mutagenesis of pyrR led to a 50- 70% decrease in the expression of pyrBC', pyrD, pyrE and pyrF while pyrC was unchanged. This suggests that PyrR is a positive activator. The upstream regions of the pyrD, py… more
Date: August 2001
Creator: Patel, Monal V.
Item Type: Refine your search to only Thesis or Dissertation
open access

A Possible Role of Ascorbate in Boron Deficient Radish (Raphanus sativa L. cv. Cherry Belle)

Description: The most apparent symptom of boron deficiency in higher plants is a cessation of growth. Deficiency causes a reduction in ascorbate concentration and the absorption of nutrient ions. Addition of ascorbate temporarily relieves deficiency symptoms. In boron sufficient plants the addition of ascorbate to media causes an increased uptake of nutrients. In an attempt to discover if ascorbate addition to deficient plants causes increased ion uptake, radish plants were grown hydroponically in four dif… more
Date: August 2001
Creator: Sedlacek, Theresa D.
Item Type: Refine your search to only Thesis or Dissertation
open access

Purification of Aspartate Transcarbamoylase from Moraxella (Branhamella) catarrhalis

Description: The enzyme, aspartate transcarbamoylase (ATCase) from Moraxella (Branhamella) catarrhalis, has been purified. The holoenzyme has a molecular mass of approximately 510kDa, harbors predominantly positive charges and is hydrophobic in nature. The holoenzyme possesses two subunits, a smaller one of 40 kDa and a larger one of 45 kDa. A third polypeptide has been found to contribute to the overall enzymatic activity, having an approximate mass of 55 kDa. The ATCase purification included the generati… more
Date: August 2001
Creator: Stawska, Agnieszka A.
Item Type: Refine your search to only Thesis or Dissertation
open access

Life History and Secondary Production of Caenis latipennis Banks (Ephemeroptera: Caenidae) in Honey Creek, Oklahoma

Description: A study of the life history and secondary production of Caenis latipennis, a caenid mayfly, was conducted on Honey Creek, OK. from August 1999 through September 2000. The first instar nymph was described. Nymphs were separated into five development classes. Laboratory egg and nymph development rates, emergence, fecundity, voltinism, and secondary production were analyzed. C. latipennis eggs and nymphs take 132 and 1709 degree days to develop. C. latipennis had an extended emergence with fiv… more
Date: August 2001
Creator: Taylor, Jason M.
Item Type: Refine your search to only Thesis or Dissertation

Development of a Pre-Impact Environmental Site Characterization for the Bryan Mound, Texas Strategic Petroleum Reserve

Description: This thesis presents a model for developing site-specific contingency plans to be used during spill response, remediation, and post-spill monitoring using the Strategic Petroleum Reserve's Bryan Mound site as a case study. Bird and vegetation observations provide baseline data for biological conditions, and sediment sampling for total petroleum hydrocarbons serves as a chemical component of the model. Results demonstrate previously unknown conditions that would hinder remediation and affect the… more
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Date: December 2001
Creator: Hernandez, Sylvia A.
Item Type: Refine your search to only Thesis or Dissertation

A laboratory course in experimental genetics for the biology major.

Description: This manual has been designed for a class of twenty- four students concurrently enrolled in the lecture course. The laboratory aids in the learning process and fosters an interest in the science of genetics. This manual and the experiments contained within are both informative and fun. The manual correlates with and expands upon the genetics course. Each investigation, with the exception of the Drosophila melanogaster project, can be completed in a 3-4 hour timeframe. This manual provides a “ha… more
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Date: December 2001
Creator: Lux, Melissa McNeil
Item Type: Refine your search to only Thesis or Dissertation

A Novel Phytoestrogen that Acts as an Agonist for Human Estrogen Receptors.

Description: Estrogen is the natural agonist of the estrogen receptor (ER). However, certain plant-derived compounds or phytoestrogens have been identified that mimic estrogens and act as agonists and/or antagonists of ERs, depending on subtype and target tissue. Understanding how phytoestrogens interact with ERs, and therefore effect the estrogenic response, may prove beneficial in hormone replacement therapy and in the prevention and treatment of hormone-related diseases. Using Thin Layer Chromatography, … more
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Date: December 2001
Creator: Pearce, Virginia
Item Type: Refine your search to only Thesis or Dissertation

Comparative Morphology of Sensilla Styloconica on the Proboscis of North American Nymphalidae and Other Selected Taxa: Systematic and Ecological Considerations.

Description: Sensilla styloconica on the proboscis of 107 species of North American and tropical butterflies were comparatively studied using the scanning electron microscope. Focus was on 76 species of North American Nymphalidae representing 45 genera and 11 subfamilies. Nomenclature for generalized and specific types of nymphalid sensilla is proposed. Written descriptions and micrographs are presented for each species studied. Morphological features were generally consistent for all or most species withi… more
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Date: December 2001
Creator: Petr, Daniel
Item Type: Refine your search to only Thesis or Dissertation
open access

A Study of the Pyrimidine Biosynthesis Pathway and its Regulation in Two Distinct Organisms: Methanococcus jannaschii and Pseudomonas aeruginosa

Description: Methanococcus jannaschii is a thermophilic methane producing archaebacterium. In this organism genes encoding the aspartate transcarbamoylase (ATCase) catalytic (PyrB) and regulatory (PyrI) polypeptides were found. Unlike Escherichia coli where the above genes are expressed from a biscistronic operon the two genes in M. jannaschii are separated by 200-kb stretch of genome. Previous researchers have not been able to show regulation of the M. jannaschii enzyme by the nucleotide effectors ATP,… more
Date: December 2001
Creator: Patel, Seema R.
Item Type: Refine your search to only Thesis or Dissertation
open access

Effector Response of the Aspartate Transcarbamoylase From Wild Type Pseudomonas Putida and a Mutant with 11 Amino Acids Deleted at the N-terminus of PyrB.

Description: Like its enteric counterpart, aspartate transcarbamoylase (ATCase) from Pseudomonas putida is a dodecamer of two different polypeptides. Unlike the enterics, the Pseudomonas ATCase lacks regulatory polypeptides but employs instead inactive dihydroorotases for an active dodecamer. Previous work showed that PyrB contains not only the active site but also the effector binding sites for ATP, UTP and CTP at its N-terminus. In this work, 11 amino acids were deleted from the N-terminus of PyrB and t… more
Date: May 2002
Creator: Asfour, Hani
Item Type: Refine your search to only Thesis or Dissertation
open access

College Freshman Biology Two Semester Course: Integrating Deep Processing Teaching Techniques

Description: Development of a college level freshman biology course was undertaken in response to government reports that American students have fallen behind students of other countries in the area of the sciences. Teaching strategies were investigated to accomplish two objectives, to define essential academic material to include in the course and to investigate teaching techniques that would increase deep processing of the information. An active process that consisted of applying the cognitive information… more
Date: May 2002
Creator: Blevins, Mary Jean
Item Type: Refine your search to only Thesis or Dissertation
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