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Effect of pH on the Persistence and Toxicity of Cyfluthrin to Chironomus Tentans

Description: The effect of pH upon the aquatic toxicity of cyfluthrin was determined in 48 h static acute toxicity tests using 2nd instar Chironomus tentans larvae. Tests were conducted in both dechlorinated tap water and lake water of pH 8.0, 7.2, and 6.6. After 48 h, immobilized and dead larvae were removed and replaced with 2nd instar larvae to assess the persistence of toxicity. Midges were cultured in water adjusted to the pH values used in testing. Toxicity if cyfluthrin varied inversely with pH. An i… more
Date: May 1992
Creator: Hambleton, Faith Ann (Faith Ann Elizabeth)
Item Type: Refine your search to only Thesis or Dissertation
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Advanced Techniques in Microbial and Molecular Biology: Laboratory Procedures for a Graduate Level Course

Description: Advanced laboratory techniques for Microbial and Molecular Biology at the graduate level are presented in this thesis. The procedures for the laboratory experiments are set forth in detail. This laboratory is conducted as two parts, each by a different professor. Part 1 covers the experiments conducted by Dr G.A.O. Donovan. These experiments include an introduction, staining procedures, biochemical reactions, mutagenesis experiment, essays,. preparation and analysis of plasmid DNA and various o… more
Date: August 1998
Creator: Kumar, Shalini
Item Type: Refine your search to only Thesis or Dissertation
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A Water Quality Study of Lake Texoma

Description: A series of four stations for sampling the waters of the Red Rivers and Lake Texoma was established. Water samples from top, middle, and bottom levels of these four stations were taken on monthly intervals during periods of homothermousity and on two-week intervals during periods of thermal stratification. These samples were analysed for the cations sodium, potassium, calcium, and magnesium, and for the anions normal carbonate, bicarbonate, sulfate, chloride, nitrate, water hardness (expressed … more
Date: June 1959
Creator: Goodman, John Willis
Item Type: Refine your search to only Thesis or Dissertation
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Effects of Nutrient Media on Growth and Morphology of Azotobacter Vinelandii

Description: The work described in this thesis was undertaken to study the reasons why Azotobacter vinelandii ATCC 12837 after incubation in Burk's nitrogen-free liquid will not form as many colonies when plated on Difco Tryptic Soy Agar as when planted on Burk's nitrogen-free agar. The difference in growth of A. vinelandii on the two agars was established by performing viable cell-plate counts. The difference in growth was most apparent at 24-hours incubation of the Burk's liquid-media cultures. Phase cont… more
Date: August 1974
Creator: Butsch, Robert W.
Item Type: Refine your search to only Thesis or Dissertation
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Assessment of Radio-Tagged Grass Carp (Ctenopharnygodon idella) Dispersion, Vegetation, and Temperature Preferences in North Lake Reservoir

Description: Twenty-nine (Group One, June 8,1995) grass carp (Ctenopharyngodon idella) and five (Group Two, April 18, 1996) grass carp were radio-tagged to monitor movement patterns and habitat preferences on North Lake, a 335 hectare multi-use reservoir located in Irving, Texas. Overall fish mean Average Daily Movement (ADM) rates were 49.2 meters/day (during Half One, 6/8/95-11/30/95) and 5.3 meters/day (during Half Two, 12/14/95-6/6/96). Aquatic macrophtye distribution data were obtained. Radio-tagged gr… more
Date: August 1996
Creator: Lacewell, Jason (Jason Lawrence)
Item Type: Refine your search to only Thesis or Dissertation
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A Comparison of Thermogenesis by Selected Substrates on Hypothermic Rat Liver

Description: The thermogenic effects in hypothermia of four substrates--alanine, glycine, ethano, and pyruvate - were studied in seventeen experiments. Albino rats were decapitated, and their livers were removed. The livers were homogenized with phosphate buffer at -5° C. After equilibration in a refrigerated Warburg apparatus at 20° C, the substrates were added and tissue respiration was recorded over three hours. Heat production was calculated from O2 uptake and CO2 production. Results showed that alanine… more
Date: August 1979
Creator: Long, James T.
Item Type: Refine your search to only Thesis or Dissertation
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Genetic Analysis of Medicago truncatula Plants with a Defective MtIRE Gene

Description: Leguminous plants are able to fix nitrogen by establishing a symbiotic relationship with soil dwelling bacteria, called rhizobia. The model plant Medicago truncatula forms a partnership with Sinorhizobium meliloti whereby the plant gains bioavailable nitrogen and in exchange the bacteria gains carbohydrates. This process occurs within nodules, which are structures produced on the roots of the plants within which nitrogen is fixed. M. truncatula incomplete root elongation (MtIRE) was localized t… more
Date: August 2015
Creator: Alexis, Naudin
Item Type: Refine your search to only Thesis or Dissertation
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Forward Genetic Characterization of Medicago truncatula Tnt1 Insertion Mutants Defective in Nodule Development and Symbiotic Nitrogen Fixation

Description: Legumes are unique plants because they form special structures “nodules”, via symbiotic relationships with rhizobial bacteria present in the soil. Once rhizobia mature inside nodules, they fix atmospheric nitrogen providing a source of bioavailable nitrogen to the plant. To discover novel genetic components involved in the legume-rhizobia symbiosis by using forward genetic screening, we have isolated Medicago truncatula Tnt1 insertion mutants in the R108 ecotype, which are defective in nodule d… more
Date: May 2015
Creator: Kadel, Khem L.
Item Type: Refine your search to only Thesis or Dissertation
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A Study of Some Congenital Anomalies of the Teeth

Description: Anomalies of the teeth include a variety of expression such as: anodontia, hyperdontia, peg teeth. opalescent dentine, mottled enamel, and other imperfections of the teeth. This paper is concerned primarily with anodontia in human subjects, although other abnormalities of interest are mentioned. Insufficient datum is the principal difficulty encountered in determining the mechanism and means of transmission in human genetics. Small families, slow breeding, and inability to subject humans to exp… more
Date: August 1955
Creator: Jones, Alvin Watt
Item Type: Refine your search to only Thesis or Dissertation
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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.
Item Type: Refine your search to only Thesis or Dissertation
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Thyroid Ultrastructural Changes Induced by Hypothermia

Description: Investigations have shown that the hypothalamus and pituitary respond to decreases in body temperature by stimulating the thyroid gland to release T3 and T4 hormones. This study was designed to investigate ultrastructural changes of the thyroid gland induced by hypothermia. The ultrastructural changes produces by stimulation by Thyroid Stimulating Hormone were also examined as an adjunct to the hypothermic stimulation of the gland. There was a significant increase in microvilli on the luminal b… more
Date: August 1979
Creator: Kent, James Simpson
Item Type: Refine your search to only Thesis or Dissertation
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An Evaluative Study of the Grasslands of the R.J. McMurry Ranch, Denton County, Texas

Description: It is the purpose of this problem to classify the four major pastures of the McMurry ranch using the discussed classification system. The definite measurable qualities characterizing each condition of the system are used extensively in this study. The problem is concerned also with the observation of results of misuse, the present practices that could result in further depletion of portions of the McMurry ranch, and procedures being employed at the present time aimed toward the restoration of t… more
Date: June 1951
Creator: Nolen, Bette Rudd
Item Type: Refine your search to only Thesis or Dissertation
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A Quantitative and Qualitative Bacterial Analysis of the Sewage Disposal System of Perryton, Texas

Description: This investigation had for its purpose the determination of first, the inefficiency of the Perryton, Texas, sewage disposal plant proper; and second the potential effectiveness of a lagoon now used to complete the sewage purification; and consequently, offset an apparent health hazard. The problem, as pursued, has consisted of first, the collection of sewage samples from the six stations listed in Table 1 over the period of time from September 23, 1949 to May 14, 1950; second, a quantitative an… more
Date: August 1950
Creator: Sullivan, Troy G.
Item Type: Refine your search to only Thesis or Dissertation
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Development of Range Condition Classes for Coleman County, Texas

Description: This paper deals with a study of the rangelands in Coleman County just west south and west of the Western Cross Timbers of Texas. This problem consists of classifying certain rangelands in this area according to whether they are excellent, fair, good, or poor, the chief basis for which is their deterioration.
Date: June 1951
Creator: McMinn, Philip Morris
Item Type: Refine your search to only Thesis or Dissertation
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The Effects of Common Electrolytes on Growth and Development of Selected Species of Aquatic Actinomycetes

Description: The role that aquatic actinomycetes play, in the production of tastes and odors in water supplies has been investigated since 1948. The ability of these organisms to produce by-products in lakes and streams, which renders the water unpalatable, is of considerable public health importance. It is desirable that the waterworks industry has as much information as possible concerning the factors that contribute to the growth of these organisms. Since it appears that the aquatic actinomycetes may be … more
Date: August 1959
Creator: Sissom, Stanley L.
Item Type: Refine your search to only Thesis or Dissertation
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Responses to Diets High in Phenylalanine Compounds as Genetic Parameters in Mice

Description: The induction of phenylketonuria in mice through the use of excess dietary phenylalanine is an area in which limited research has been done. This study intends to pursue further work in this area, more specifically, to study the effects of excess dietary phenylalanine and the phenylalanine analogue A.P.B.A. (2-amino-3-phenyl butanoic acid) (7) on brain serotonin and brain norepinephrine. In addition, the effects of these two compounds on the incidence of audiogenic seizures will be explored.
Date: June 1966
Creator: Boughey, Frederick W.
Item Type: Refine your search to only Thesis or Dissertation
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Microflora in Prepared Foods Dispensed from Eating Establishments in Dallas, Texas

Description: A bacteriological study was made of a number of prepared foods that were bought ready-to-eat, for home consumption, from several food establishments in Dallas, Texas. The purpose of this study was to show whether these foods could be a potential source of food poisoning; whether there are any particular foods that should have greater care than others in order to protect their quality; and whether the bacteriological contamination could have been prevented by strict observance of the city regula… more
Date: August 1948
Creator: Phillips, Margaret
Item Type: Refine your search to only Thesis or Dissertation
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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
Item Type: Refine your search to only Thesis or Dissertation
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Effect of Light and Other Environmental Factors on Growth and Carotenogenesis of Corynebacterium Species Strain 7E1C

Description: This investigation studies effects of environmental factors on growth and carotenogenesis in Corynebacterium strain 7ElC. Changes in pH were found to effect growth more than carotenogenesis. However, certain nutrients or long incubation periods stimulated carotenoid formation more than growth. Dark conditions in a mineral salts-glucose medium stimulated growth, but minimized carotenogenesis. Tryptic soy broth or yeast extract elicited carotenogenesis in darkness. Although brief light exposure d… more
Date: August 1974
Creator: Howard, Marta E.
Item Type: Refine your search to only Thesis or Dissertation
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Primary Productivity and Community Metabolism in a Small North Central Texas Pond Ecosystem

Description: Rates of primary production and community metabolism were monitored over a one year period using the diurnal oxygen method. Certain physico-chemical parameters were also measured, and autotrophic standing crops were estimated. An in-depth study was made of the phytoplankton community and various diversity indicies were calculated. Simple correlations were run between all parameters measured (biotic and abiotic), and their inter-relationships examined. Multiple linear regression analyses were us… more
Date: August 1975
Creator: Kelly, Martin H.
Item Type: Refine your search to only Thesis or Dissertation
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The Population Dynamics and Trophic Relationships of Seven Species of Fish in a Small Southwestern Pond, with Special Attention Toward Young-of-the-Year Fish

Description: Production rates of seven species of fish, along with food-web interactions, were determined for one year in a pond. Production of fish in the pond amounted to 208.9 q/m2/yr. Over 95% of the production occurred in the summer, with Y of Y fish contributing 83.8%. There were two food-web interactions observed in Y of Y fishes: crappie vs. bass and bullhead vs. sunfish. When Y of Y fish shifted to benthic diets in the spring, the small biomass of benthos available could not sustain the larger bio… more
Date: August 1975
Creator: Jones, Fredrick V.
Item Type: Refine your search to only Thesis or Dissertation
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