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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A preliminary assessment for the use of metabolic inhibitors to evaluate the biodegradation potential of soil

Lantz, Robert Michael 10 June 2012 (has links)
The widespread contamination of our nation's groundwater has become a major threat to public health. The magnitude of this threat is escalated by our reliance upon groundwater. Groundwater is the primary drinking water source for over 50% of the U.S. population. Groundwater comprises more than 95% of all available freshwater in the United States. The objectives of this study were: (1) to make a preliminary assessment of the use of inhibitors to evaluate the biodegradation potential of soil, and (2) to evaluate the significance of each microbial group in the biodegradation process. Static microcosms containing Newport News and Blacksburg soil were used as the experimental environments. Butyrate and propionate were used as substrates. The metabolic inhibitors used were sodium molybdate (Na.7N1o04) and 2-Bromoethane sulfonic acid (BESA), which inhibit sulfate reduction and methanogenesis, respectively. Denitrification was suppressed by the absence Of sodium nitrate (NaNO3) in the microcosm dilution water. Both Newport News and Blacksburg soils were found to be dominated by denitrfying bacteria. In nitrate-amended Newport News microcosms, 300 mg/L butyrate degraded to .zero concentration in 5.5 days. This microcosm's degradation "rate" was 255% greater than non-nitrate amended microcosms, where sulfate reduction was predominant. Little or no methanogenic activity was observed in both the Newport News or Blacksburg soils. Advantages of this approach are its simplicity and directness in obtaining approximately the same information as more complicated enumeration procedures. A disadvantage of this approach is its reliance on metabolic inhibitors to suppress the microbial activity of specific microbial groups. Little is known on the effect of Na2MoO4 or BESA on the activities of denitrifiers, fermenters, or acetogens. / Master of Science
2

Inside and Outside 1101: First-Year Student Perceptions of Academic Writing

Jones, Laura E 14 December 2011 (has links)
First-year undergraduate students have vastly different perceptions of academic writing, the writing process, and the value of writing within their specific academic disciplines. These perceptions differ not only from their instructors but also from their peers. Yet, while reams of literature discuss, debate, and decipher student perspectives of writing from a scholarly point of view, the first-year student voice is conspicuously absent from this discussion. This study followed 92 first-year students through their first college composition course, English 1101, in order to capture the student perspective of how writing fits in their academic careers. The results indicate that while most students acknowledge first-year composition to be essential to their academic development, few report writing assignments in courses outside of 1101. This raises questions about how students identify writing activities and also suggests avenues for further inquiry, particularly the need for follow-up research at the culmination of their undergraduate careers.
3

Inside and Outside 1101: First-Year Student Perceptions of Academic Writing

Jones, Laura E 14 December 2011 (has links)
First-year undergraduate students have vastly different perceptions of academic writing, the writing process, and the value of writing within their specific academic disciplines. These perceptions differ not only from their instructors but also from their peers. Yet, while reams of literature discuss, debate, and decipher student perspectives of writing from a scholarly point of view, the first-year student voice is conspicuously absent from this discussion. This study followed 92 first-year students through their first college composition course, English 1101, in order to capture the student perspective of how writing fits in their academic careers. The results indicate that while most students acknowledge first-year composition to be essential to their academic development, few report writing assignments in courses outside of 1101. This raises questions about how students identify writing activities and also suggests avenues for further inquiry, particularly the need for follow-up research at the culmination of their undergraduate careers.

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