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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.
151

Diet and water source of Pleistocene Lamini camelids based on stable isotopes of tooth enamel: Implications for North American vegetation and paleoclimate

Yann, Lindsey Theresa 23 June 2014 (has links)
<p>Arid adapted taxa have evolved to live in some of the harshest environments on Earth, yet the adaptations that allowed them to transition from mesic to arid landscapes is poorly understood. Members of Camelidae (camels, vicunas, guanacos) provide a unique opportunity to study past climates as their ancestors are ubiquitous in the fossil record and all extant taxa live in arid environments. This dissertation examines Pleistocene Lamini camelids (<em>Camelops</em>, <em>Hemiauchenia</em>, <em>Palaeolama</em>); to better understand the paleoecology of the ancestors of modern South American camelids (<em>Vicugna</em>, <em>Lama</em>). To reconstruct the diet and ecology of these camelids, stable carbon (δ<sup>13</sup>C) and oxygen (δ<sup>18</sup>O) isotope values were used as a proxy for the vegetation and water consumed by herbivores. An aridity index was further developed and identified camelids as sensitive to changes in aridity. Examination of community sites in Florida suggests that warmer and drier sites had more heterogeneous environments during the Pleistocene, and likely provided the vegetation needed to support closely related taxa. In response to warmer temperatures and more heterogeneous environments, <em>Hemiauchenia</em>, <em>Platygonus</em>, and <em>Mylohyus </em>modified their dietary niches, but δ<sup>13</sup>C values suggest that <em>Equus</em>, <em>Mammut</em>, <em>Palaeolama</em>, and <em>Tapirus</em> were dietary specialist. The integration of δ<sup>13</sup>C and δ<sup>18</sup>O values indicates that <em>Palaeolama</em> was a specialized forest browser that did not modify its dietary niche in response to environmental changes or changes in the faunal composition of past ecosystems. This interpretation is further supported by its frequent co-occurrence with forest browsing <em>Tapirus</em> and <em>Odocoileus</em>.  <em>Hemiauchenia</em> was a true dietary generalist that could modify its diet in response to environmental changes and/or the presence of either <em>Palaeolama </em>or <em>Camelops</em>. Potential consumption of C<sub>4</sub> saltbush suggests <em>Camelops</em> was an opportunistic browser that may have taken advantage of its large body size and varied browsing diet to co-occur with <em>Palaeolama</em> or <em>Hemiauchenia</em>. Co-occurrence with a broader range of taxa further suggests that <em>Hemiauchenia</em> and <em>Camelops</em> lived in a range of habitats. This work further clarifies the isotopic ecology of three Pleistocene Lamini camelids, and suggests the opportunistic behavior of <em>Hemiauchenia</em> and its descendants potentially allowed for the adaptation to harsh, arid environments. </p>
152

South African environmental taxes and investment incentives in practice

Harris, Peter-Dirk 12 1900 (has links)
Thesis (MBA)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: The South African economy is faced with a number of challenges as an upper-middle income country that is highly resource-intensive, with an open economy. It has a number of developmental goals that must be achieved in order to maintain environmentally conscious sustainable development. The country will have to find pioneering ways to address the poverty problems faced by a large proportion of its people, while still ensuring economic growth at a reduced cost to the environment. In an effort to promote the shift to a “green” economy, the South African state and its related entities have developed a number of incentive programmes aimed at easing the transition. These incentives primarily support businesses in their efforts to become more energy-efficient, or to convert to renewable energy sources. The objective of this study is to critically evaluate what the South African government is doing with regard to environmental instruments aimed at assisting the country to reduce carbon emissions. This case study follows a quantitative approach, considering the financial effects that the different environmental instruments could have on South African manufacturers. Through the study the researcher will be able to make certain recommendations to businesses in the manufacturing industry who are interested in investing in renewable energy and energy efficiency. The results of the study will also give the researcher insight into the South African environmental incentives, which will allow him to make informed comments on the proposals that government has tabled regarding future environmental taxes and incentives. The research questions that the researcher tried to answer were based on the current and future policy measures that the South African government has implemented, or will implement, in order to move the country to a low-emissions trajectory. These policies were then also compared to international measures in order to determine if the policies chosen by the South African government are appropriate for the this country’s economy. This study has led the researcher to discover a number of issues relating to the status of environmental policy in South Africa. These discoveries have allowed him to make certain recommendations to businesses investing in this realm, as well as to government which develops these policy measures. The main findings of the study are that with the assistance of the South African government and related entities, investments in renewable energy have become viable. When considering the current status of South African environmental policy, the researcher has also come to realise that the country is lagging behind the rest of the world with regard to policy development. The South African economy is unique, thus policies have to be structured in a way that will not be detrimental to the country.
153

A Hunter's Shadows: A Personal Exploration of Hunting

Giese, James 20 June 2014 (has links)
Hunting has a long history in the U.S. that has evolved as the country has progressed. In a way, each hunter also has their own history that evolves as they age. This collection of essays is a look into my history with hunting and some of the ways it has evolved. On initial read these essays have an obvious common thread of hunting and they follow me as I rediscover moments in my life that have influenced my journey to where I am today as a hunter. But the essays also go beyond the act of hunting and delve into my relationships with influential people, places, and landscapes in my life. One of the goals in crafting these essays was to explore various reasons why I choose to be a hunter and to examine why I made an unconscious decision to stop killing animals in 2007a reprieve that would end while writing this collection. Another goal was to make these essays relatable to a wide audiencehunters, non-hunters, and anyone considering hunting. Hunters, perhaps, will recognize some of the struggles, questions, joys and heartbreaks addressed here. For non-hunters, my hope is that I have offered a honest look into hunting that may lessen some stereotypes. For someone considering hunting these essays provide candid fodder for what it is like to hunt and some insight into the potential internal struggles that hunters carry. I knew the core of writing these essays would be to explore my connectionpast, present, and futureto hunting. But like many things in life, what begins as perceived simplicity quickly becomes a much greater task. The more consideration I gave this topic, the more I realized that this journey would not be as simple as trying to find out answers to "this is why I hunt" or "this is why I no longer hunted." As I have discovered these essays do not provide a concrete answer to my many questions. Instead, they have established a foundation for my continued exploration into why I desireor desire notto call myself a hunter.
154

Determination of Predominant Species of Oil-degrading Bacteria in the Oiled Marsh Sediment in Barataria Bay, Louisiana

Navarre, Lauren Nicole 07 May 2014 (has links)
The effects of the Deepwater Horizon (DWH) oil spill on the bacterial communities in coastal sediments are relatively known but few studies have been published evaluating the impacts of the spill on oil-degrading bacterial populations in the salt marsh sediments of Barataria Bay, Louisiana. The aims of this study were to determine the effects of the oil spill on the microbial community in Barataria Bay, Louisiana through the determination of predominate species of oil-degrading bacteria in marsh sediments, and to determine how well certain bacterial isolates can degrade crude oil in the region by taking samples from three areas of different oiling categories in April 2012, October 2012 and April 2013, approximately 24, 30, and 36 months after the initial oiling event. Hydrocarbon-degrading bacteria were isolated from the sediment samples using Bushnell Haas (BH) agar enriched with 1% Light Louisiana Sweet (LLS) crude oil. The isolates were subsequently purified on LB agar plates, their genomic DNAs extracted, and 16S rRNA genes amplified by polymerase chain reaction (PCR). The PCR products of 16S rRNA were then sequenced and taxonomically classified based on similarity to known sequences in BLAST database. A total of 460 isolates were obtained, representing 84 species from 45 genera in 6 phyla. Oil degradability of 10 bacterial isolates, designated to Staphylococcus xylosus, Acinetobacter calcoaetious, Pseudomonas stutzeri, Bacillus pumilus, Micrococcus luteus, Rhodococcus equi, Microbacterium esteratomaticum, Vibrio sp., Pseudomonas mendocina, and Agromyces aurantiacus, respectively, was tested in LB broth with 1% LLS crude oil. Their growth and metabolic properties in terms of optical density at 600 nm and pH in culture medium were monitored for 6 days. Among these isolates, Micrococcus luteus, Vibrio sp., Bacillus pumilus, Rhodococcus equi and Microbacterium esteratomaticum appeared to have the greatest ability to degrade LLS crude oil; their growth rates were estimated to be 0.038, 0.037, 0.031, 0.029 and 0.037 per hour, respectively. All isolates showed a decrease in pH in their culture medium during their growth, with M. esteratomaticum having the lowest pH of 5.29 and R. equi having the highest pH of 6.50 at 96 hours of incubation. A decrease in pH in the cultured media is indicative of an accumulation of acid from oxidation reactions carried out by oil-degrading bacteria. The present study provided a comprehensive list of indigenous oil-degrading bacteria in Louisiana marsh sediment, which is critical in developing bioremediation strategies.
155

Kinetic studies of lactic acid production from wood extract hydrolysate via batch and continuous fermentation processes

Buyondo, John Paul 03 May 2014 (has links)
<p> The research work presented in this dissertation describes kinetic studies of batch and continuous fermentation of hemicelluloses to lactic acid. Sugar maple wood chips were subjected to hot water to extract hemicelluloses, predominantly as oligomers. Hemicelluloses oligomers were hydrolyzed to fermentable monomeric sugars by dilute acid hydrolysis and concentrated by nanofiltration process. The concentrated wood extract hydrolysate contained 138.7 g/L xylose, 22.2 g/L mannose, 18.7 g/L glucose, 10.7 g/L galactose, 4.6 g/L arabinose, and 5.2 g/L rhamnose. The effect of initial sugar loading was investigated by diluting the concentrated wood extract hydrolysate to obtain desired total sugar concentrations. In the batch fermentation process lower total sugar concentration led to the highest lactic acid yield of 0.83 g/g using <i> Lactobacillus pentosus</i> ATCC 8404 cells. Acetic acid was produced as the byproduct. Adaptation of <i>Lactobacillus pentosus</i> strain to concentrated wood extract hydrolysate led to 10 h reduction in batch fermentation time and 15.5% increase in lactic acid production. </p><p> Adapted <i>Lactobacilus</i> pentosus cells were used to study the kinetics of lactic acid production via batch and continuous fermentation processes. The continuous fermentation process led to higher lactic acid productivity and lower acetic acid to lactic acid ratios ranging between 0.27 and 0.60 as compared to the batch fermentation process which had 0.62 acetic acid to lactic acid ratio. For both batch and continuous fermentation processes all wood hemicellulosic sugars were utilized with glucose being the preferred sugar whereas the rest of sugars were simultaneously utilized. </p><p> A kinetic model for batch lactic acid fermentation from hemicellulosic sugars was developed. Kinetic parameters were determined by ODEXLIMS routine to solve a set of ordinary differential equations for biomass growth rate, product formation rate and substrate utilization rate while minimizing the variance between experimental and predicted values using Microsoft Excel<sup> &reg;</sup> solver. The model performed satisfactorily for predicting the transient responses of biomass growth, product formation and substrate utilization with squared Pearson correlation coefficient (R<sup>2</sup>) ranging between 0.97 and 0.99 for the initial substrate (total hemicellulosic sugar) concentrations of 40.0 g/L and 55.0 g/L.</p>
156

The Relative Importance of Physicochemical Properties of Organic Contaminants in Aquatic Ecosystems

Saranjampour, Parichehr 07 February 2017 (has links)
Measured physical/chemical properties of chemicals can be impacted by varying environmental conditions, subsequently influencing chemical environmental fate and exposure. For example, salinity has been reported to influence the water solubility of organic chemicals entering marine ecosystems. However, there is limited data available on salinity impacts on chemical sorption as well as bioavailability and exposure estimates used in the chemicals regulatory assessment. The salinity impact were demonstrated on the estimates of environmental fate of model compounds with different polarities including pesticides, and polycyclic aromatic sulfur heterocycles (PASHs). The n-octanol/water partition coefficient (KOW) was measured in both distilled-deionized water as well as artificial seawater (3.2%). A linear correlation curve estimated salinity may increase the log KOW value 2.6% per one log unit increase in distilled water (R2 = 0.968). The water solubility, bioconcentration factor, organic carbon soil/sediment sorption coefficient, and acute toxicity in fish were estimated for chemicals using the measured log KOW values by EPI SuiteTM. The water solubility of pesticides was measured in both distilled-deionized water as well as artificial seawater (3.2%). Salinity appears to generally decrease the water solubility and increase partitioning potential. Environmental fate estimates indicate elevated chemical sorption to sediment, bioavailability, and toxicity in artificial seawater suggesting that salinity should be accounted when conducting exposure estimates for marine organisms. In addition, the relative impact of volatilization and hydroxyl radical degradation on estimates of PASH overall dissipation after entry into aquatic ecosystems as a function of depth (0.1, 1 and 2 m) were investigated using the EPA Exposure Analysis Modeling System (EXAMS). The hydroxyl radical rate constant (K.OH) and Henrys law constant (H) of PASHs were determined in distilled water. Simulated dissipation of PASHs using EXAMS suggest that volatilization is a dominant fate pathway for the higher molecular weight and less polar C2-DBT and C4-DBT at all depths and DBT and C1-DBT at 0.1 m. However, model scenarios suggest hydroxyl radical degradation may significantly contribute to the degradation of more polar DBT and C1-DBT at 1 m and 2 m depths.
157

Narratives of the Permaculture Home| A Case Study on Northwest Residential Permaculture

Gilda, Jennifer Marie 10 February 2017 (has links)
<p> The goal of this study is to share real stories and perspectives about integrating permaculture design in a residential setting, from those with in-depth experience. This study begins with a brief look at the convergence of pertinent contexts, including climate change, the sustainability movement, and the importance of the residential scale. Then it moves into reviewing theoretical literature about permaculture theory and design, particularly the definition, development, ethics, and design principles. The study uses a case study methodology. Seven interviews on residential permaculture sites in the Northwest region were gathered and thematically analyzed. The research results are a collection of narratives and a presentation of themes. The narrative stories are not utopic; they are a realistic view into what a developing permaculture system looks like around the home setting. The research confirms important points of permaculture theory and design, and offers an inspiring set of stories and advice relevant to the permaculture movement at large, to the Northwest region, and to those working towards a more sustainable way of life.</p>
158

Pharmaceuticals and personal care products in an effluent-dominated stream| Seasonal variability and downstream fate

Buswell, Bradley R. 25 April 2017 (has links)
<p>Wastewater treatment plant (WWTP) effluents are major sources of pharmaceuticals and personal care products (PPCPs) in the environment and effluent-dominated streams (EDSs) represent worst-case scenarios for PPCP exposures to aquatic organisms. The concentrations of PPCPs downstream from a WWTP can be altered by dilution and fate processes such as biodegradation, photodegradation and sorption. The relative importance of these processes depends on the individual PPCPs and environmental variables that vary seasonally. The primary objective of this study was to determine the concentrations of selected PPCPs in an EDS as a function of season and distance from a WWTP with the hypothesis being that the downstream attenuation of the PPCPs would vary based on their corresponding physicochemical properties. A secondary objective was to evaluate the ability of the constructed wetlands located between the plant and creek to reduce PPCP concentrations. Samples were collected seasonally from above and below the East Canyon Water Reclamation Facility (ECWRF) and within the constructed wetlands for selected PPCPs. Except for caffeine, downstream PPCP concentrations were higher than upstream, indicating that the ECWRF effluent is the major source of PPCPs in East Canyon Creek. Generally, the highest PPCP concentrations in the stream were observed in July and the lowest in May corresponding to the times of lowest and highest ratio of stream to effluent flows, respectively. Dilution was the major factor associated with the declining PPCP concentrations downstream of the ECWRF but the extent of decline varied between compounds suggesting other fate mechanisms also play a role. Sorption of PPCPs to wetland sediments was greater than stream sediments but overall the retention time within the wetlands was too short to significantly reduce the amount of PPCPs moving into the stream. The observed concentrations of individual PPCPs in East Canyon Creek were lower than those expected to negatively impact the health of aquatic organisms but mixture effects are still a potential concern.
159

Landscapes of Belonging| Systematically Marginalized Students and Sense of Place and Belonging in Outdoor Experiential Education

Goodman, Cecil 03 June 2017 (has links)
<p> This qualitative case study explores the intersection of social justice pedagogy and Outdoor Experiential Education (OEE) sense of place and belonging curriculum. The purpose of this study was to gain a comprehensive understanding of, and engage in critical analysis of how students systematically marginalized by race, ethnicity, and/or class experienced sense of place and belonging in OEE. Data was collected through in-depth interviews of OEE Students and Interns of Color, and White OEE field instructors at one program site, as well as through the critical textual analysis of program materials. Theoretical and conceptual frameworks for this study used Critical Race Theory, critical multiculturalism, the cultural construction of the Outdoors, and core concepts from OEE scholarship. Data analyses revealed existing institutional and curricular inequities in OEE for Students of Color. To address these systemic inequities, findings supported the adoption of social justice pedagogy across the field of OEE. Specific recommendations for future practice as a result of the research included the implementation of equity and inclusion trainings for field instructors, professional development programs for OEE field instructors and administrators of Color, and the development of curriculum across the field of OEE to understand the implications of the cultural construction of the Outdoors in order to better serve a racially and ethnically diverse OEE student population.</p>
160

The Effectiveness of ISCO Injection Methods for Remediation of Groundwater

Vidrine, Matthew Ryan 05 May 2017 (has links)
In-Situ Chemical Oxidation (ISCO) injections were performed at Petro Stopping Centers # 10 (Petro) in December 2013 and June 2015. The methodology was direct injection of a heavy oxidizer, RegenOx®, followed by a time-release oxygen compound, ORC Advanced®, into a plume of gasoline sitting on top of the water in the aquifer in hope that this remediate the aquifer. Both chemicals are registered trademarks of the Regenesis® Company. The levels of contaminates have dropped considerably. However, Petro has not achieved closure criteria according to RECAP standards. The site is classified as a GW-1B, subject to the most stringent of remediation standards, due to its ability to be used as a drinking water source. The analytical results show undulating contaminate levels, dropping to below detectable levels then resurging to levels above acceptable RECAP standards. Levels show steady decline in all the monitoring wells including downgradient monitoring wells. The undulating phenomenon can be explained by desorption of COCs, incidental spilling of gasoline, or the clays affinity for organics. Further investigation into the clay will provide a better idea of which hypothesis is closer to the truth. During a sampling event, 3/19/15, levels were below detectable concentrations in all samples. Lab error offers a possible explanation for this event, the site still has contamination on it, if that sampling event produced clean samples is highly suspect. The injections were successful at bringing gasoline contaminate concentrations down directly after an injection period. The method is effective and easy to apply. The resurgence of contaminates at this site is up for discussion and further study but, the method of remediation used at Petro is an effective tool in remediating a gasoline contaminated aquifer. Suggestions for improving the effectiveness of this method with the use of other injection materials in conjunction with the chemicals used in this project are mentioned in the discussion and conclusion sections of this thesis. Data referenced in this thesis is publicly available at the Louisiana Department of Environmental Quality document search website EDMS under the Agency Interest(AI) number 5962.

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