UNT Libraries - 6 Matching Results

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Degradation of Humic Substances by Aquatic Bacteria

Description: A variety of aquatic bacteria were isolated and tested for their ability to degrade humic substances and their aromatic residues/monomers which serve as precursors of the trihalomethanes (THMs) found in chlorinated drinking waters. The majority of them were Gram-negative, oxidative types dominated by pseudomonads. Most of the 146 isolates were found to utilize as their sole source of carbon several or more of ten aromatic compounds known to be products of degradation of humus and also to be pre… more
Date: August 1985
Creator: Baiu, Saleh Hamed Salem
Item Type: Refine your search to only Thesis or Dissertation
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Effects of Water Source, Suspended Solids, and Acclimation on Biotransformation of 2 /4-Dichlorophenoxy Acetic Acid in Aquatic Systems

Description: In recent years there has been a great deal of scientific interest in processes that affect the fate of organic chemicals in the environment. one main reason for this increased interest is due to greater environmental concern over accidental or purposeful release of these chemicals into the environment by man. A major environmental concern is the increased use of pesticides over the last few years. In the thirty years prior to 1978 the use of pesticides has increased by a factor of forty (Ridge… more
Date: August 1985
Creator: Moses, Christopher K. (Christopher Karam)
Item Type: Refine your search to only Thesis or Dissertation
open access

Factors Inhibiting Dissociation Of Neisseria gonorrhoeae Cells

Description: The initial studies reported in this dissertation were attempts to induce mutations in those genes which control dissociation in cells of Nei sseria gonorrhoeae. These studies led to an investigation of survival curves of cells grown in liquid media. Instead of survival curves reflecting the diploid nature of gonococci, multiple cell kinetics were observed. It was found that large clumps contained a predominance of cells of the T2 type and that when these clumps were dispersed by DNAase, it app… more
Date: August 1982
Creator: Gonzalez, Anthony H.
Item Type: Refine your search to only Thesis or Dissertation
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Size Fractionation of Metabolically Active Phytoplankton and Bacteria in Two Diverse Lentic Systems

Description: Simultaneous size fractionation of plankton populations associated with NaH^14CO_3 and ^3H-glucose uptake was employed in eutrophic Lake Texoma (Texas and Oklahoma) and oligotrophic Flathead Lake (Montana). Autoradiography was utilized to determine the role of specific microorganisms in community metabolism. Ultraplankton (0.45-10 μm) dominated plankton numbers and metabolic activity in both aquatic systems. Many of the most abundant species were not the most productive, in terms of inorganic C… more
Date: August 1980
Creator: Ellis, Bonnie K.
Item Type: Refine your search to only Thesis or Dissertation

Submerged wood inhabiting macoinvertebrates of the Elm Fork of the Trinity River, Texas: Assemblage analyses, comparisons to the benthic fauna, and a study of Cyrnellus fraternus (Trichoptera: Polycentropodidae)

Description: Taxonomic composition and spatio-temporal variability of macroinvertebrates inhabiting snags were examined from an 8-km segment of the Elm Fork of the Trinity River. Seventy-seven macroinvertebrate taxa were collected from submerged wood during the study. Assemblages were highly variable spatially and temporally, especially among seasons. An ordination of species and environment did not find snag taxa to have striking correlations with many of the selected environmental variables, although ther… more
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Date: August 2001
Creator: Johnson, Zane B.
Item Type: Refine your search to only Thesis or Dissertation
open access

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
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