UNT Theses and Dissertations - 309 Matching Results

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Comparative Ultrastructural Study between Young and Adult forms of Trypanosoma Lewisi

Description: The purpose of this study was to examine the ultrastructure of both young (dividing form) and adult (stationary form) of Trypanosoma lewisi. Changes observed between the two forms of the organism were related directly to data obtained from previous comparative biochemical studies conducted on these forms of Trypanosoma lewisi.
Date: August 1973
Creator: Abdul-Salam, Jasem M.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Immunofluorescence as a Method for the Rapid Identification of Streptococcus Faecalis in Water

Description: The development and refinement of FA has been adequately investigated with major emphasis on pathogenic microorganisms. The development of this technique has reduced both the time and number of biochemical tests necessary to identify a diversity of organisms. The organisms included are the protozoans, as described by Goldman (1953 and 1957) and by Ingram (1961), viruses, as reported by Liu (1955a) and Burgdorfer and Lackman (1960a), pathogenic bacteria which have been investigated by Moody, Gol… more
Date: August 1970
Creator: Abshire, Robert Louis
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Partner: UNT Libraries
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Degradation of Phenolic Acids by Azotobacter Species Isolated from Sorghum Fields

Description: Sorghum plants excrete phenolic acids which reduce subsequent crop yields. These acids accumulate in field soil by combining with soil and clay particles to form stable complexes which remain until degraded by bacterial metabolism. The amount of phenolic acids in soil samples were obtained by gas chromatography measurements, while Azotobacter populations were obtained by plate counts in 40 sorghum field samples from Denton County, Texas. One can conclude that increasing the Azotobacter populati… more
Date: August 1989
Creator: Al-Hadhrami, Mohamed N. (Mohamed Nasser)
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Partner: UNT Libraries
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Effects of Phytohormones on Scenedesmus quadricauda

Description: The literature on the effects of phytohormone on algae is clouded with contradictory reports. Reports have been published which substantiate and deny the effects of phytohormones in enhancing the growth and developmental processes in algae. The overall aim of this study was to investigate the response, if any, of the phytohormones indole-3-acetic acid (IAA), gibberellic acid A3 (GA) and kinetin on the physiology of the green alga, Scenedesmus quadricauda. Results obtained for the uptake of 14^C… more
Date: August 1977
Creator: Alam, Mohammad Ihtisham
Item Type: Refine your search to only Thesis or Dissertation
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Systematics of the Stonefly Tribe Suwalliini Surdick and Behavioral Studies of Selected Species in the Stonefly Families Chloroperlidae and Perlidae

Description: The purpose of this study is to revise the genus Suwallia and to evaluate the potential taxonomic importance of adeagal and other genitalic characters, adult pigment patterns and egg characters. The revision concentrates on western North American species while providing coverage of all species, except Suwallia asiatica Zhiltzova and Lavanidova where only presumed females have been available for study. Communication and mate locating behaviors in adult stoneflies are critical for life cycle comp… more
Date: August 1997
Creator: Alexander, Kevin D. (Kevin Dewayne)
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Analysis of Multipartite Bacterial Genomes Using Alignment-Free and Alignment-Based Pipelines

Description: In this work, we have performed comparative evolutionary analysis, functional genomics analysis, and machine learning analysis to identify the molecular factors that discriminate between multipartite and unipartite bacteria, with the goal to decipher taxon-specific factors and those that are prevalent across the taxa underlying the these traits. We assessed the roles of evolutionary mechanisms, namely, horizontal gene transfer and gene gain, in driving the divergence of bacteria with single and… more
Date: August 2021
Creator: Almalki, Fatemah
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

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

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… more
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Date: August 2004
Creator: Anvari, Sara
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Inquiry-based science for high school students: a forensic unit

Description: This project constitutes an instructional unit for honors biology that involves the use of science in the field of criminal investigation and forensics. Before beginning the unit, the learners should have mastered basic laboratory skills, including use of the microscope. They should also have an understanding of the basic structure and function of DNA and its role in heredity and protein synthesis. The standard time frame is 24 days with 70-minute periods, but can be easily adjusted to meet cla… more
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Date: August 2000
Creator: Apple, Kendra Kea
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Food, Feeding Selectivity, and Ecological Efficiencies of Fundulus notatus (Rafinesque) (Osteichthyes; Cyprinodontidae)

Description: This study was made to further define the trophic dynamics of Fundulus notatus by determining its ration composition under natural conditions, measuring feeding selectivity under various laboratory conditions of prey-species composition and availability, and determining the efficiencies with which F. notatus utilizes ingested chironomid larvae.
Date: August 1970
Creator: Atmar, Gerald Legare
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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The Influence of a Return of Native Grasslands upon the Ecology and Distribution of Small Rodents in Big Bend National Park

Description: In the southwestern United States there is a delicate balance between the existing grasslands and the rodent fauna. The purpose of this investigation was to determine the influence of secondary succession of native grasslands upon the ecology and distribution of small rodents. Two methods of determining the rodent species were plot quadrates and trap lines using Sherman live traps.
Date: August 1971
Creator: Baccus, John T.
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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
Partner: UNT Libraries
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The Use of Similarity Indicies to Assess the Spatial Differences of the Phytoplankton Communities in Lake Ray Roberts, Texas

Description: A study of the phytoplankton communities of Lake Ray Roberts was conducted at three sampling sites on two sampling dates during the summer of 1995, assessing both community structure and chlorophyll a concentrations. Eight similarity indices were then used to characterize and compare the communities of these sites. Both community similarity and chlorophyll a concentrations were evaluated using a minimum detectable difference equation to determine the amount of change that must occur in these pa… more
Date: August 1996
Creator: Banks, Kenneth E. (Kenneth Edward)
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Degradation of Homologous Polymerized Deoxyribonucleic Acid by Azotobacter Vinelandii ATCC 12837

Description: The purpose of this study was twofold. The first was to isolate, purify, and characterize the deoxyribonucleic acid (DNA) of Azotobacter vinelandii ATCO 12837. The second was to determine if there was irreversible binding of homologous 32P labeled DNA to recipient A. vinelandii cells.
Date: August 1972
Creator: Barnes, Wayne Riley
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Comparison of Aspartate Transcarbamoylase and Pyrimidine Salvage in Sporosarcina urea, Sprolactobacillus inulinus, Lactobacillus fermentum, and Micrococcus luteus

Description: The enzyme that catalyzes the committed step in pyrimidine biosynthesis, aspartate transcarbamoylase, has been compared in selected endospore-forming organisms and in morphologically similar control organisms. The ATCases and pyrimidine salvage from Sporosarcina ureae, Sporolactobacillus inulinus, Lactobacillus fermentum, and Micrococcus luteus were compared to those of Bacillus subtilis. While the ATCases from Sporosarcina ureae, Sporolactobacillus inulinus, and L. fermentum were found to exhi… more
Date: August 1994
Creator: Barron, Vincent N. (Vincent Neal)
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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A Study of a Selected Group of Science Related Characteristics of Non-Science Majors

Description: The purpose of this study is to gather information related to the characteristics of two groups of undergraduate non-science majors; namely, those students who once considered science as a career and subsequently changed to a non-science major and those who have never considered a career in science. It is frequently observed that children in the elementary school have an intense interest in science. One of the principal concerns of this study is how and for what reasons has the interest in scie… more
Date: August 1957
Creator: Bearden, Bennie Paul
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Partner: UNT Libraries
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The Effect of Sodium Salicylate on the Ultrastructure of Trypanosoma lewisi

Description: This study examines ultrastructural changes occurring in seven- and fourteen-day populations of Trypanosorfa lewisi when 60 mg sodium salicylate is administered to the host. These changes were related to the host-immune response. Seven-day trypanosomes showed approximately 10 posterior volutin granules. Seven-day trypanosomes whose host had received salicylate exhibited. 30 to 40 volutin granules, and their posterior tip exhibited volutin granules in high numbers sometimes excluding other cellu… more
Date: August 1974
Creator: Beck, Charles F.
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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
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Documentation of Biodiversity Impacts (Including Cumulative Biodiversity Impacts) in Environmental Impact Statements

Description: In the United States, biodiversity impact assessment has historically received little attention. Responding in 1993, the Council on Environmental Quality (CEQ) released guidelines on incorporating biodiversity into environmental impact assessment under the National Environmental Policy Act of 1969. The objectives of the study here were to identify the level of documentation of biodiversity impact assessment in sample Environmental Impact Statements (EISs); identify whether in the years followin… more
Date: August 1998
Creator: Bhatia, Sarika
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Assessment of Changes in Aquatic Macrophyte Occurrence Following Introduction of Triploid Grass Carp in a North Texas Reservoir

Description: The objectives of this project were to measure changes in frequency of occurrence of submerged macrophytes over the first two growing seasons following stocking with triploid grass carp at two fish per acre and to measure differences in macrophyte biomass between areas excluded from herbivory and adjacent control sites after 16 months following establishment of exclosures. The project also seeks to measure concentrations of fluridone following the herbicide treatment, and to compare two methods… more
Date: August 1997
Creator: Bickel, Ken (Kenneth E.)
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Cardio-Respiratory Ontogeny and the Transition to Bimodal Respiration in an Air Breathing Fish: Morphological and Physiological Development in Normoxia and Hypoxia.

Description: As selection pressures exist for not only adults, but for every life history stage, it is important to understand how environmental factors shape developing animals. Despite the significance placed on aquatic hypoxia as a driving force in the evolution of air breathing, this is the first known study to examine the effects of hypoxia on cardio-respiratory ontogeny of an air breathing fish. Blue gouramis are obligatory air breathing fish that possess a labyrinth-like structure that serves as th… more
Date: August 2009
Creator: Blank, Tara M.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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