You limited your search to:
- The Environmental is Political: Exploring the Geography of Environmental Justice
- The dissertation is a philosophical approach to politicizing place and space, or environments broadly construed, that is motivated by three questions. How can geography be employed to analyze the spatialities of environmental justice? How do spatial concepts inform understandings of environmentalism? And, how can geography help overcome social/political philosophy's redistribution-recognition debate in a way that accounts for the multiscalar dimensions of environmental justice? Accordingly, the dissertation's objective is threefold. First, I develop a critical geography framework that explores the spatialities of environmental injustices as they pertain to economic marginalization across spaces of inequitable distribution, cultural subordination in places of misrecognition, and political exclusion from public places of deliberation and policy. Place and space are relationally constituted by intricate networks of social relations, cultural practices, socioecological flows, and political-economic processes, and I contend that urban and natural environments are best represented as "places-in-space." Second, I argue that spatial frameworks and environmental discourses interlock because conceptualizations of place and space affect how environments are perceived, serve as framing devices to identify environmental issues, and entail different solutions to problems. In the midst of demonstrating how the racialization of place upholds inequitable distributions of pollution burdens, I introduce notions of "social location" and "white privilege" to account for the conflicting agendas of the mainstream environmental movement and the environmental justice movement, and consequent accusations of discriminatory environmentalism. Third, I outline a bivalent environmental justice theory that deals with the spatialities of environmental injustices. The theory synergizes distributive justice and the politics of social equality with recognition justice and the politics of identity and difference, therefore connecting cultural issues to a broader materialist analysis concerned with economic issues that extend across space. In doing so, I provide a justice framework that assesses critically the particularities of place and concurrently identifies commonalities to diverse social struggles, thus spatializing the geography of place-based political praxis.
- Evaluation of the Developmental Effects and Bioaccumulation Potential of Triclosan and Triclocarban Using the South African Clawed Frog, Xenopus Laevis
- Triclosan (TCS) and triclocarban (TCC) are antimicrobials found in U.S. surface waters. This dissertation assessed the effects of TCS and TCC on early development and investigated their potential to bioaccumulate using Xenopus laevis as a model. The effects of TCS on metamorphosis were also investigated. For 0-week tadpoles, LC50 values for TCS and TCC were 0.87 mg/L and 4.22 mg/L, respectively, and both compounds caused a significant stunting of growth. For 4-week tadpoles, the LC50 values for TCS and TCC were 0.22 mg/L and 0.066 mg/L; and for 8-week tadpoles, the LC50 values were 0.46 mg/L and 0.13 mg/L. Both compounds accumulated in Xenopus. For TCS, wet weight bioaccumulation factors (BAFs) for 0-, 4- and 8-week old tadpoles were 23.6x, 1350x and 143x, respectively. Lipid weight BAFs were 83.5x, 19792x and 8548x. For TCC, wet weight BAFs for 0-, 4- and 8-week old tadpoles were 23.4x, 1156x and 1310x. Lipid weight BAFs were 101x, 8639x and 20942x. For the time-to-metamorphosis study, TCS showed an increase in weight and snout-vent length in all treatments. Exposed tadpoles metamorphosed approximately 10 days sooner than control tadpoles. For the hind limb study, although there was no difference in weight, snout-vent length, or hind limb length, the highest treatment was more developed compared to the control. There were no differences in tail resorption rates between the treatments and controls. At relevant concentrations, neither TCS nor TCC were lethal to Xenopus prior to metamorphosis. Exposure to relatively high doses of both compounds resulted in stunted growth, which would most likely not be evident at lower concentrations. TCS and TCC accumulated in Xenopus, indicating that the compound has the potential to bioaccumulate through trophic levels. Although TCS may increase the rate of metamorphosis in terms of developmental stage, it did not disrupt thyroid function and metamorphosis in regards to limb development and tail resorption.
- Habitat Fragmentation by Land-Use Change: One-Horned Rhinoceros in Nepal and Red-Cockaded Woodpecker in Texas
- This research focuses on the spatial analysis of the habitat of two vulnerable species, the one-horn rhinoceros in the grasslands of southern Nepal, and the red-cockaded woodpecker in the Piney woods of southeast Texas, in the USA. A study sites relevant for biodiversity conservation was selected in each country: Chitwan National Park in Nepal, and areas near the Big Thicket National Preserve in Texas. Land-use differs in the two study areas: the first is still undergoing agrarian development while the second is in a technological phase and undergoing urbanization processes. Satellite remote sensing images were used to derive land-cover maps by supervised classification. These maps were then processed by Geographic Information Systems methods to apply habitat models based on basic resources (food and cover) and obtain habitat suitability maps. Several landscape metrics were computed to quantify the habitat characteristics especially the composition and configuration of suitable habitat patches. Sensitivity analyses were performed as the nominal values of some of the model parameters were arbitrary. Development potential probability models were used to hypothesize changes in land-use of the second study site. Various scenarios were employed to examine the impact of development on the habitat of red-cockaded woodpecker. The method derived in this study would prove beneficial to guide management and conservation of wildlife habitats.
- Role of N-Acylethanolamines in Plant Defense Responses: Modulation by Pathogens and Commercial Antimicrobial Stressors
- N-acyl ethanolamines (NAEs) are a class of lipids recently recognized as signaling molecules which are controlled, in part, by their degradation by fatty acid amide hydrolase (FAAH). On the basis of previous studies indicating increased NAE levels in a tobacco cell suspension-xylanase elicitor exposure system and the availability of FAAH mutants, overexpressor and knockout (OE and KO) genotypes in Arabidopsis thaliana, further roles of NAEs in A. thaliana plant defense was investigated. The commonly occurring urban antimicrobial contaminant triclosan (TCS) has been shown to suppress lipid signaling associated with plant defense responses. Thus, a second objective of this study was to determine if TCS exposure specifically interferes with NAE levels. No changes in steady state NAE profiles in A. thaliana-Pseudomonas syringae pv. syringae and A. thaliana-flagellin (bacterial peptide, flg22) challenge systems were seen despite evidence that defense responses were activated in these systems. There was a significant drop in enoyl-ACP reductase (ENR) enzyme activity, which catalyzes the last step in the fatty acid biosynthesis pathway in plants, on exposure of the seedlings to TCS at 10 ppm for 24 h and decreased reactive oxygen species (ROS) production due to flg22 in long term exposure of 0.1 ppm and short term exposure of 5 ppm. However, these responses were not accompanied by significant changes in steady state NAE profiles.