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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.
21

Toxicology of Decabromodiphenyl Ether in Avian Embryos: Disposition of the Flame Retardant BDE-209 in Yolk-Injected Chicken Embryos (Gallus gallus)

Sifleet, Samantha D. 01 January 2009 (has links)
Polybrominated diphenyl ethers (PBDEs) are flame retardant chemicals of toxicological concern present in humans, wildlife, and the environment. Deca-BDE is the highest production product due to historical use patterns and recent regulatory limitations on the other two commercial formulations (Penta-BDE and Octa-BDE) in the U.S and Europe. The EU banned Deca-BDE starting July 1, 2008. However, it remains in usage in North America and elsewhere in the world. BDE-209 is the dominant congener in all Deca- BDE commercial products. BDE-209 has been reported to under go metabolic debromination to lesser brominated and more toxic and bioaccumulative congeners. However, insufficient data are available on this process. It has also been observed that congener profiles and BDE-209 levels in terrestrial organisms differ from most aquatic species, indicating accumulation or metabolic dissimilarity. The goal of this in ovo study is to determine the biotransformation and tissue distribution of BDE-209 after injection into the yolk-sac of embryonic chickens. An emulsion formulation was employed to better distribute the hydrophobic BDE-209 within the eggs in an attempt to better mimic “natural” exposure of embryos. Acute mortality from BDE-209 yolk injection was observed. An LD50 value of 44 μg/egg (740 ng/g ww) was determined for embryonic chickens in this study. Concentrations of BDE-209 and possible metabolic degradates were determined in five compartments of the embryos (yolk, brain, liver, heart and remaining carcass). The results indicated that some BDE-209 was mobilized from the yolk, into the carcass, liver, brain, and heart tissues of the developing chicken embryo prior to pipping. However, 80% of the dose was detected as BDE-209 in the yolk sac. Additional BDE-209 would likely have been assimilated following hatching and resorption of the remaining yolk. Nona-BDEs were detected in all of the liver and yolk samples from BDE-209 exposed eggs. The congener profiles of the different tissues did not indicate that significant metabolic debromination of BDE-209 occurred within the developing embryos.
22

Persistent Organic Pollutants(POPs) as Tracers of Environmental Change and Antarctic Seabird Ecology

Geisz, Heidi N. C. 01 January 2010 (has links)
Antarctic seabirds including Adelie penguins (Pygoscelis adeliae), south polar skuas (Catharacta maccormicki), southern giant petrels (Macronectes gigantus) are high trophic level predators that accumulate persistent organic pollutants (POPs) present in the food webs in which they forage. Little is known about the levels of POPs in some Antarctic organisms (e.g. southern giant petrels), as well as the long-term trends of POPs in the Antarctic ecosystem. Samples from all three seabird species were collected post mortem, including eggs, from the Western Antarctic Peninsula (WAP) and in the Ross Sea throughout the austral summer breeding seasons of 2004--2006. The samples were analyzed for C and N stable isotopes and POPs including organochlorine pesticides, polychlorinated biphenyls (PCBs), and brominated diphenyl ethers (BDEs). The objectives of this study were to: (1) evaluate the long-term trends of POP residues in Adelie penguins, (2) compare POP levels within livers of the three seabird species based on migratory patterns and trophic level using stable isotope analysis of delta15N and delta13C, and (3) demonstrate POPs can be used as tracers of Antarctic seabird ecology. POPs in Antarctic biota were first evaluated using Adelie penguin tissues and a long-term analysis including data from the current study showed SigmaDDT has not declined in WAP penguins for more than 30 years. Indeed, the presence of p,p'-DDT in these birds indicates that there is a current source of DDT to the WAP marine food web, and both measurements and calculations suggest that this source of DDT is related to climate driven environmental change in the region. A more broad analysis including all three seabird species showed SigmaPCBs, SigmaDDTs, Sigmachlordanes and mirex are 3--100 times higher in migratory seabird livers than the endemic penguins, while hexachlorobenzene (HCB) exhibits no difference in concentration between the three seabird species. Model predictions compared to measured output of delta13C and delta13N indicate a stronger correlation between delta13C and less volatile POP concentrations demonstrating the heavy influence of winter migration on the contaminant loads of seabirds that breed in Antarctica. Finally, discrepancies in POP ratios between migratory and endemic seabird eggs and fat in combination with stable isotope signatures gave insight into seabird evolutionary breeding strategies. For example, the relative abundance of SigmaPCBs was highest in south polar skua eggs and endogenous lipid input into skua eggs was estimated at >79% by examining discrepancies in contaminant ratios. The combined stable isotope and contaminant data indicate that south polar skuas and southern giant petrels employee different combinations of income and capital breeding strategies.
23

Distribution of Organochlorine Pollutants in Sea Turtles

Rybitski, Mary J. 01 January 1993 (has links)
No description available.
24

The Development of a Water Quality Model in Baltimore Harbor, Back River, and the Adjacent Upper Chesapeake Bay

Liu, Hui 01 January 2002 (has links)
No description available.
25

Sublethal Effects of Sediment Contamination on an Estuarine Amphipod

Vogt, Bruce W. 01 January 2003 (has links)
No description available.
26

Measuring the Applicability of the Seville Strategy to the Mammoth Cave Area Biosphere Reserve

Kreitzer, Debra 01 May 1998 (has links)
The dominant paradigms of the past decade involve the preservation of biodiversity through the use of landscape corridors and buffer zones, as well as the integration of economic growth through sustainable use. The International Biosphere Reserve (IBR) program, as defined in the Seville Strategy, encourages locations already involved in conservation to continue to protect biodiversity and foster harmonious relationships between humans and their environment through sustainable development. An excellent example of an IBR is the Mammoth Cave Area Biosphere Reserve (MCABR) in south-central Kentucky. In order to measure the significance of the implementation of the Seville Strategy in the MCABR, a methodology was developed which not only measures the implementation level of the Seville Strategy, but also the policies involved in the implementation procedure. Twenty-four indicators, designed by the authors of the Seville Strategy, were analyzed. These indicators were broken down into three categories, administrative, research, and educational indicators. The results of the analysis show that the implementation of the MCABR has had a significant impact on the biodiversity, environmental management, and sustainable development of the Mammoth Cave area. This methodology has the potential to successfully measure other IBR programs at the local, national, or international level.
27

Development of an Atmospheric Fluidized Bed Combustor (AFBC)

Orndorff, William 01 December 1997 (has links)
The relatively recent interest in the U.S. in the development of atmospheric fluidized bed combustion (AFBC) has been preceded by two main factors. First of these is the ever present problem of acid rain and growing public support for cleaner burning fossil fuels. Second is the increasing demand on public landfills and subsequent need for burning of municipal solid waste. From these factors and their corresponding influences, Western Kentucky University has the impetus and has received the financial assistance necessary to build and develop a laboratory scale AFBC system. A brief history of the events leading to this development, as well as selected results from the last 12 months of this project are discussed.
28

Evaluation of Continuous Flow Constructed Wetlands Treating Swine Waste

Rivard, Stephanie 01 May 1997 (has links)
The ability for wetlands to purify contaminated water is not a new concept. Natural wetlands have been cleansing water within our environment for ages. After studying the process of natural wetlands the same concept was applied to municipal waste. It is the success of constructed wetlands treating municipal waste that created the new idea for the application of a wetland system to treat wastewater from livestock facilities. Through proper design and management, constructed wetlands may be useful for reducing the nutrient concentration of waste (Rieck el al., 1996). Taking into consideration the higher nutrient loads of livestock waste, the same basic idea of constructed wetlands used for municipal waste is being utilized to protect public water sources from contamination of livestock wastes. In this study a constructed wetland (total recycle) built for the purification of swine waste was evaluated. In cooperation with Pig Improvement Company of Allen County, Kentucky, water samples were collected from the nine connected cells making up the wetlands created at The Dogwood Ridge Farm. After collection of the samples, they were analyzed at the Western Kentucky University Environmental Laboratory. Samples were tested for levels of the following parameters: • Ammonia Nitrogen • Nitrate Nitrogen • Total Phosphorus • Biological Oxygen Demand • Total Suspended Solids • Total Dissolved Solids • Fecal Coliform • Conductivity • Mineral Elements The data in this report accounts for seven sample dates throughout 1996. Samples were also collected for three additional months prior to the first sample date in which data is reported, although these dates are considered to be a part of the initial start up phase for the testing period. Sample dates within the start up phase are not included among the results. With greater concern directed towards higher water quality standards, there is the need to eliminate any activities resulting in non-point source pollution (NPS). Livestock waste is considered one of the leading causes of NPS pollution which has created this awareness for better waste management. As traditional waste treatment equipment is commonly too expensive for the average livestock producer, constructed wetlands are proving to be an affordable, environmentally friendly, and manageable solution for livestock waste treatment.
29

Sustainability of Western Kentucky University: An Examination of Campus Environmental Policies, Performance and Potential for Change

Ryan-Downing, Christian 01 December 2007 (has links)
Institutions of higher learning are in a pivotal position to address the environmental problems that global society faces now, but response to this challenge requires transformation in priorities and practices. Recognizing the impacts that universities have on the environment and the social and economic costs associated with these impacts, institutions of higher learning are changing policies and management to become more sustainable. Sustainability is defined by the World Commission on Environment and Development as "development that meets the needs of the present without compromising the ability of future generations to meet their own needs" (1987). To evaluate the environmental impacts and level of sustainability at Western Kentucky University, ten indicators were assessed: Building Design, Energy, Water, Land, Air, Solid Waste, Purchasing, Transportation, Food and Dining, and Environmental Literacy. Average annual energy consumption for each campus community member is 4,139 kWh of electricity, 527 pounds of coal, 3,600 cf of natural gas, totaling over 22 million Btus, costing $317 and emitting 3.34 metric tons of greenhouse gas emissions. Additionally, 14,244 gallons of water are used, and 248 pounds of solid waste are generated per campus community member annually. WKU's physical growth provides opportunities to incorporate elements of energy efficiency and sustainable design into new buildings and renovations that provide permanent savings in energy and water. University energy costs and carbon footprint can be reduced through initiatives including physical and policy change and education campaigns that engage students, faculty, and staff. Sustainable building design and construction and energy conservation have indirect positive impacts, reducing water use, blending with the natural landscape, and reducing water and air pollutants. Less than 4% of WKU's solid waste is recycled. Investment in recycling infrastructure can make recycling economically self-supported through revenue and avoided landfill fees. WKU has no policy for environmentally responsible purchasing. A "green purchasing" guide could promote the use of recycled content paper, and energy efficient appliances. University shuttles are decreasing carbon emissions by using 5% biodiesel, and plan to increase the blend. Campus-community initiatives such as bike lending and expanding shuttle service are progress toward sustainability. Further steps could include purchase of university fleet hybrid cars and a ride-share program for commuters. According to Worldwatch Institute, food transportation is the biggest, fastest growing source of greenhouse gas emissions worldwide. WKU food services could decrease the university's carbon footprint while supporting the local economy by using food produced locally, and reduce environmental impacts and landfill fees by composting food waste. A survey sent to WKU faculty requesting submissions of courses including sustainability as a concept resulted in 42 courses from within four main campus Colleges. Ecological literacy is essential in preparing students to be productive and engaged citizens of a global society. Efforts toward sustainability reduce the university ecological footprint and have far-reaching positive impacts in reduced operating costs, improved quality of services to students and faculty, and providing a model for local communities. Universities invested in sustainability also give their graduates critical knowledge and skills to find creative solutions to challenges facing society.
30

The Whitehead Link on the Cubic Lattice

Haynes, Elizabeth 01 August 2007 (has links)
The cubic lattice is a graph in Â3 where the vertices are points with integer coordinates and edges are unit length line segments parallel to the x-, y-, or z-axis. A step is a line segment that connects one vertex to a neighboring vertex one unit away in the x-, y-, or z-direction. This thesis will show that the Whitehead Link needs at least 34 steps to be embedded on the cubic lattice.

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