Social feasibility assessment for establishing habitat areas using built structures in Austin, Texas

textThis thesis is as social feasibility assessment for establishing habitat areas using parking garages in Austin, Texas. The research does not propose a design solution, but seeks to understand key stakeholder perceptions towards the establishment of habitat areas. A constructivist epistemological approach is the foundational framework for this research, supported by literature in regenerative architecture, civic environmentalism, and urban ecology. Through interviewing multiple stakeholders on the goals, opportunities, barriers, and benefits for using built structures as habitat areas, as well as researching local governance and costs structures, the social feasibility is uncovered. In the interview process respondents brought up themes, which are categorized into two broad groups, noted as habitat and social characteristics. Species mentioned by respondents are combined within the habitat characteristics category, and the topics primarily focus on functionally suitable systems for Austin’s current, and future climate scenarios. Within the social category, the need for increased public education on the opportunities and benefits for establishing habitat areas, better coordination among habitat focused groups, and increased municipal financial supports, are the primary subjects discussed. Overall, the conclusion of this research outlines potential future research opportunities to further understand the social feasibility for establishing habitat areas, using built structures, in Austin, Texas.Architectur

Hydrological connectivity in vegetated river deltas : the effects of spatial variability and patchiness on channel-island exchange

River deltas are threatened regions of great societal and environmental importance, and their continued survival depends upon a greater understanding of their formation and evolution. Hydrological connectivity in river deltas is important for delivering flow and sediment to the island interior and is responsible for a large portion of the ecosystem benefits that deltas provide, which could be leveraged for restoration projects using nature-based engineering. However, the process is still poorly understood. The roughness of island vegetation is known to significantly limit channel-island connectivity, but the importance of the spatial distribution of vegetation is, as-of-yet, unknown. Using a 2D hydrodynamic model, we investigate the influence of vegetation percent cover, patch size, and stem density on the fraction of discharge allocated to the islands of an idealized delta complex, modeled after the Wax Lake Delta in coastal Louisiana. We find that spatial heterogeneity can substantially alter connectivity when vegetation is dense and covers less than a “disconnectivity” threshold near 50% of the island domain, near the theoretical percolation limit. Above this threshold, models can accurately approximate vegetation as uniform. Below this threshold, however, preferential flow-paths develop in the islands, which greatly alter the hydraulics, transport capabilities, and residence time distribution of the delta complex, with respect to what is seen in uniform vegetation cases. Our results suggest that patchiness has substantial hydrogeomorphic and biogeochemical implications which should be considered when modeling deltaic systems.Civil, Architectural, and Environmental Engineerin

A Structural Perspective of Antibody Neutralization of Dengue Virus

The four dengue viruses: DENV) are mosquito-borne flaviviruses and are considered the world\u27s most significant arboviruses in terms of worldwide disease burden. Symptoms of dengue disease are classified into dengue fever, a mild, febrile illness, and the potentially fatal severe dengue, which can include hemorrhaging and shock. Antibody protection against DENV correlates with the production of neutralizing antibodies against the envelope: E) glycoprotein. To understand the role of antibodies in DENV infection, we sought to dissect the relationship between epitope and function. Virologic studies had identified that the most potently neutralizing antibodies are against domain III: DIII) of the E protein. We have identified five epitopes within DENV DIII. Our data suggests that the most potently neutralizing antibodies are specific for a single serotype, while cross-reactive antibodies are relatively poorly neutralizing. Additionally, we were surprised to define neutralizing epitopes that were shown to be inaccessible on the surface of the virion in cryo-electron microscopy studies. Fine epitope mapping was used to define the epitopes of a panel of existing DENV-2 antibodies. Antibodies against the lateral ridge were the most potently neutralizing antibodies and reacted only with the DENV-2 serotype. The second epitope was centered on the DIII A-strand, and antibodies against this epitope reacted with several serotypes of DENV. Several poorly neutralizing antibodies reacted to all four DENV serotypes, as well as West Nile virus, a related flavivirus, mapped to the highly conserved AB loop of DIII. We expanded our studies of DIII-specific antibodies to the DENV-1 serotype. One antibody, E106, potently neutralized the five DENV-1 strains representing the five genotypes, and bound a composite epitope of the lateral ridge and A-strand epitopes. Despite the potency of E106-mediated neutralization, a combination of structural, biophysical, virologic data suggest that potent DENV-1 neutralization by E106 is coincident with bivalent engagement of the virus. Additionally, we determined the crystal structures of E111 bound to a novel fifth CC\u27 loop epitope on domain III: DIII) of the E protein from two different DENV-1 genotypes. The available atomic models of DENV virions revealed that the E111 epitope was inaccessible, suggesting that it recognizes an uncharacterized virus conformation. While the affinity of binding between E111 and DIII varied by genotype, we observed limited correlation with inhibitory activity. Instead, our results support the conclusion that potent neutralization depends on genotype-dependent exposure of the CC\u27 loop epitope. These findings establish new structural complexity of the DENV virion, which may be relevant for the choice of DENV strain for induction or analysis of neutralizing antibodies in the context of vaccine development

Diversification of Ergot Alkaloid Biosynthesis in Natural and Engineered Fungi

Ergot alkaloids are a complex family of tryptophan-derived mycotoxins produced by a diverse range of fungi that occupy a wide variety of ecological niches including soil saprotrophs, plant endophytes, pathogens of plants or insects, and opportunistic pathogens of humans and other mammals. Ergot alkaloids are a similarly diverse family of chemicals that elicit a variety of pharmacological activities in animals due to their resemblance to neurotransmitters and high binding affinity for neurological receptors, including those that bind adrenaline, dopamine, and 5-hydroxytryptamine receptors. These structural similarities allow us to create medicines aimed at treating a range of neurological diseases and disorders including dementia, migraines, and Parkinson’s. The genes encoding ergot alkaloid biosynthesis are found clustered together in the genomes of the different fungi that make them. The fungus Metarhizium brunneum produces lysergic acid α-hydroxyethylamide (LAH), an ecologically and pharmaceutically relevant compound, as its main ergot alkaloid and secretes most of this compound into the surrounding environment. The first objective of this study involved engineering M. brunneum to produce the dihydrogenated versions of its natural ergot alkaloids, that is dihydrolysergic acid (DHLA) and dihydroLAH. The results showed that the fungus can produce both products and was also found to secrete most of both compounds at levels comparable to their unsaturated counterparts. The fungus Aspergillus leporis is a soil saprotroph that has been previously shown to have evolved the capacity for LAH production independently of species in the Clavicipitaceae. Two partial, fragmented gene clusters encoding different clavine-type ergot alkaloid branches were discovered in separate areas of the A. leporis genome and formed the basis for a second study. Chemical analyses indicated that fumigaclavine A production is encoded by one of the fragmented gene clusters. Concentrations of fumigaclavine A peaked around 15 days, following a decrease in LAH levels. The other partial cluster encoded two enzymes necessary to complete production of rugulovasines A and B, but rare production in A. leporis indicated some unknown environmental stimuli required for their production. Expression of these two genes in an appropriate background of M. brunneum allowed for confirmation of their function. The fungus Aspergillus fumigatus, an opportunistic human pathogen, is a known producer of fumigaclavines, another branch of clavine ergot alkaloids, and a distant relative to A. leporis. Due to this relation, A. fumigatus was chosen as platform with which to study the activity and localization of a novel gene from A. leporis, named easT, that encodes a putative major facilitator superfamily transporter. The results indicate that the transporter encoded by easT localizes to discrete regions of fungal hyphae independent of mCherry-tagged peroxisomes and plays a role in transport of ergot alkaloids and/or their precursors. Collectively, the results presented here showcase different ways that ergot alkaloid production can be diversified in both natural and engineered fungal systems

A mineral survey of Louisiana beef cow/calf production systems

The purpose of this research was to determine the state and regional mineral status of Louisiana forages and beef cattle. Louisiana beef cattle operations (n = 25) were sampled and divided into seven geographical regions, including the northwest (NW), northeast (NE), central (CE), southwest (SW), south central (SC), Florida parishes (FP) and southeast (SE) regions. Over a two year period, water and soil samples were collected from each operation annually, forage samples were collected quarterly in Aug to Sep, Nov to Dec, Feb to Mar and May to June and bovine serum samples were collected twice annually in the fall and spring seasons. The highest (P \u3c 0.05) average regional water K and S concentrations were observed in the SE region and water Ca and Mg concentrations were the highest (P \u3c 0.05) in the NE, CE and SE regions. However, all water mineral concentrations, with exception of Na, were lower than the reported upper desired levels considered safe for livestock consumption (Socha et al., 2003). Similar to water, soil Ca, Mg and K concentrations in our study, were higher (P \u3c 0.05) in the SE compared to all other regions. Soil Cu concentrations were below critical levels in the CE region and all soil Zn concentrations, except the SE region, were lower than reported critical levels indicating soil deficiency. The average forage concentration for each mineral were: Ca (0.42%), P (0.28%), Mg (0.21%), K (1.83%), Na (0.10%), S (0.32%), Cu (8.12 ppm), Fe (323.46 ppm), Mn (254.85 ppm) and Zn (41.29 ppm). In addition, only mean forage Cu concentrations were lower than minimum requirements and regional forage K (NW region), Mg (FP region), Na (CE region) and S (NW and SE regions) concentrations were higher (P \u3c 0.05) than other regions. The average regional serum K concentration in the NE region was higher (P \u3c 0.05) than all other regions. Average bovine serum mineral concentrations in Louisiana were: Ca (9.02 mg/100 ml), P (13.62 mg/100 ml), Mg (1.92 mg/100 ml), K (21.66 mg/100 ml), Na (303.30 mg/100 ml), S (103.31 mg/100 ml), Cu (0.63 µg/ml), Fe (7.44 µg/ml), Zn (1.28 µg/ml), Mn (8.08 ng/ml) and Se (64.48 ng/ml). Furthermore, of these minerals, serum Mg, Na, Cu and Mn concentrations were lower than critical levels, indicative of deficiency