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Over the past century in the southwestern United States human actions have altered hydrological processes that shape riparian ecosystems. One change, release of treated wastewater into waterways, has created perennial base flows and increased nutrient availability in ephemeral or intermittent channels. While there are benefits to utilizing treated wastewater for environmental flows, there are numerous unresolved ecohydrological issues regarding the efficacy of effluent to sustain groundwater-dependent riparian ecosystems. This research examined how nutrient-rich effluent, released into waterways with varying depths to groundwater, influences riparian plant community development. Statewide analysis of spatial and temporal patterns of effluent generation and release revealed that hydrogeomorphic setting significantly influences downstream riparian response. Approximately 70% of effluent released is into deep groundwater systems, which produced the lowest riparian development. A greenhouse study assessed how varying concentrations of nitrogen and phosphorus, emulating levels in effluent, influenced plant community response. With increasing nitrogen concentrations, vegetation emerging from riparian seed banks had greater biomass, reduced species richness, and greater abundance of nitrophilic species. The effluent-dominated Santa Cruz River in southern Arizona, with a shallow groundwater upper reach and deep groundwater lower reach, served as a study river while the San Pedro River provided a control. Analysis revealed that woody species richness and composition were similar between the two systems. Hydric pioneers (Populus fremontii, Salix gooddingii) were dominant at perennial sites on both rivers. Nitrophilic species (Conium maculatum, Polygonum lapathifolium) dominated herbaceous plant communities and plant heights were greatest in effluent-dominated reaches. Riparian vegetation declined with increasing downstream distance in the upper Santa Cruz, while patterns in the lower Santa Cruz were confounded by additional downstream agricultural input and a channelized floodplain. There were distinct longitudinal and lateral shifts toward more xeric species with increasing downstream distance and increasing lateral distance from the low-flow channel. Patterns in the upper and lower Santa Cruz reaches indicate that water availability drives riparian vegetation outcomes below treatment facilities. Ultimately, this research informs decision processes and increases adaptive capacity for water resources policy and management through the integration of ecological data in decision frameworks regarding the release of effluent for environmental flows.
ContributorsWhite, Margaret Susan (Author) / Stromberg, Juliet C. (Thesis advisor) / Fisher, Stuart G. (Committee member) / White, Dave (Committee member) / Holway, James (Committee member) / Wu, Jianguo (Committee member) / Arizona State University (Publisher)
Created2011
Description
Driven by concern over environmental, economic and social problems, small, place based communities are engaging in processes of transition to become more sustainable. These communities may be viewed as innovative front runners of a transition to a more sustainable society in general, each one, an experiment in social transformation. These experiments present learning opportunities to build robust theories of community transition and to create specific, actionable knowledge to improve, replicate, and accelerate transitions in real communities. Yet to date, there is very little empirical research into the community transition phenomenon. This thesis empirically develops an analytical framework and method for the purpose of researching community transition processes, the ultimate goal of which is to arrive at a practice of evidence based transitions. A multiple case study approach was used to investigate three community transitions while simultaneously developing the framework and method in an iterative fashion. The case studies selected were Ashton Hayes, a small English village, BedZED, an urban housing complex in London, and Forres, a small Scottish town. Each community was visited and data collected by interview and document analysis. The research design brings together elements of process tracing, transformative planning and governance, sustainability assessment, transition path analysis and transition management within a multiple case study envelope. While some preliminary insights are gained into community transitions based on the three cases the main contribution of this thesis is in the creation of the research framework and method. The general framework and method developed has potential for standardizing and synthesizing research of community transition processes leading to both theoretical and practical knowledge that allows sustainability transition to be approached with confidence and not just hope.
ContributorsForrest, Nigel (Author) / Wiek, Arnim (Thesis advisor) / Golub, Aaron (Thesis advisor) / Redman, Charles (Committee member) / White, Dave (Committee member) / Arizona State University (Publisher)
Created2011
Description
The sacred San Francisco Peaks in northern Arizona have been at the center of a series of land development controversies since the 1800s. Most recently, a controversy arose over a proposal by the ski area on the Peaks to use 100% reclaimed water to make artificial snow. The current state of the San Francisco Peaks controversy would benefit from a decision-making process that holds sustainability policy at its core. The first step towards a new sustainability-focused deliberative process regarding a complex issue like the San Francisco Peaks controversy requires understanding the issue's origins and the perspectives of the people involved in the issue. My thesis provides an historical analysis of the controversy and examines some of the laws and participatory mechanisms that have shaped the decision-making procedures and power structures from the 19th century to the early 21st century.
ContributorsMahoney, Maren (Author) / Hirt, Paul W. (Thesis advisor) / Tsosie, Rebecca (Committee member) / White, Dave (Committee member) / Arizona State University (Publisher)
Created2011
Description
Despite similar climate, ecosystem, and population size, the cities of Hermosillo, Mexico and Mesa, USA manage their water very differently. Mesa has a stable and resilient system organized around state and federal regulations. Hermosillo, after rapidly industrializing, has not been able to cope with climate change and long-term drought conditions. Water distribution statistics, stakeholders, policy structure, and government organization were combined in an organizational framework to compare the practices of the two cities. These inputs were weighed against the outcomes and the sustainability of each system. While Mesa is part of a massive metropolitan area, Hermosillo is still developing into a metropolitan center and does not have access to the same infrastructure and resources. In Hermosillo local needs are frequently discounted in favor of broad political goals.
ContributorsMoe, Rud Lamb (Author) / Chhetri, Netra (Thesis director) / White, Dave (Committee member) / Robles-Morua, Agustin (Committee member) / Barrett, The Honors College (Contributor) / School of Earth and Space Exploration (Contributor) / School of Sustainability (Contributor) / School of Geographical Sciences and Urban Planning (Contributor)
Created2013-05
Description
This dissertation investigates the condition of skeletal muscle insulin resistance using bioinformatics and computational biology approaches. Drawing from several studies and numerous data sources, I have attempted to uncover molecular mechanisms at multiple levels. From the detailed atomistic simulations of a single protein, to datamining approaches applied at the systems biology level, I provide new targets to explore for the research community. Furthermore I present a new online web resource that unifies various bioinformatics databases to enable discovery of relevant features in 3D protein structures.
ContributorsMielke, Clinton (Author) / Mandarino, Lawrence (Committee member) / LaBaer, Joshua (Committee member) / Magee, D. Mitchell (Committee member) / Dinu, Valentin (Committee member) / Willis, Wayne (Committee member) / Arizona State University (Publisher)
Created2013
Description
While exercising mammalian muscle increasingly relies on carbohydrates for fuel as aerobic exercise intensity rises above the moderate range, flying birds are extraordinary endurance athletes and fuel flight, a moderate-high intensity exercise, almost exclusively with lipid. In addition, Aves have long lifespans compared to weight-matched mammals. As skeletal muscle mitochondria account for the majority of oxygen consumption during aerobic exercise, the primary goal was to investigate differences in isolated muscle mitochondria between these species and to examine to what extent factors intrinsic to mitochondria may account for the behavior observed in the intact tissue and whole organism. First, maximal enzyme activities were assessed in sparrow and rat mitochondria. Citrate synthase and aspartate aminotransferase activity were higher in sparrow compared to rat mitochondria, while glutamate dehydrogenase activity was lower. Sparrow mitochondrial NAD-linked isocitrate dehydrogenase activity was dependent on phosphate, unlike the mammalian enzyme. Next, the rate of oxygen consumption (JO), electron transport chain (ETC) activity, and reactive oxygen species (ROS) production were assessed in intact mitochondria. Maximal rates of fat oxidation were lower than for carbohydrate in rat but not sparrow mitochondria. ETC activity was higher in sparrows, but no differences were found in ROS production between species. Finally, fuel selection and control of respiration at three rates between rest and maximum were assessed. Mitochondrial fuel oxidation and selection mirrored that of the whole body; in rat mitochondria the reliance on carbohydrate increased as the rate of oxygen consumption increased, whereas fat dominated under all conditions in the sparrow. These data indicate fuel selection, at least in part, can be modulated at the level of the mitochondrial matrix when multiple substrates are present at saturating levels. As an increase in matrix oxidation-reduction potential has been linked to a suppression of fat oxidation and high ROS production, the high ETC activity relative to dehydrogenase activity in avian compared to mammalian mitochondria may result in lower matrix oxidation-reduction potential, allowing fatty acid oxidation to proceed while also resulting in low ROS production in vivo.
ContributorsKuzmiak, Sarah (Author) / Willis, Wayne T (Thesis advisor) / Mandarino, Lawrence (Committee member) / Sweazea, Karen (Committee member) / Harrison, Jon (Committee member) / Gadau, Juergen (Committee member) / Arizona State University (Publisher)
Created2012
Description
The storm events of summer 2014 proved to be some of the highest on record for Maricopa County. Flash flooding has been an ongoing issue within Arizona during the monsoon season due to the remnants of hurricanes that result in short, high intensity storms. The proximity of these intense storm events and their corresponding flooding structures is imperative in reducing the impact of these events on the community. The analysis of the maximum precipitation events for Tempe, Scottsdale, Phoenix, Mesa, Chandler, Goodyear, Peoria, Avondale and Glendale during the summer of 2014 proved that there were many events that had a calculated recurrence of 100 years or greater. The storm event with the most precipitation events with a recurrence of 100 years or greater was September 8, 2014. This storm event also produced a streamflow response that had the highest recorded streamflow at gages near the events with a 100 year recurrence. These intervals represent a larger amount of rain during a precipitation event and this correlation suggests that short burst of extreme weather was not a trend in this data. Rather, high storm events occurred over the span of 24 hours. The most frequent response of the stream gage to this rain event was a streamflow event that has a recurrence of 2-5 years. This suggests that the channels and flooding structures used to contain the rain events were effective in reducing the amount of water and therefore effectively managing the flooding response. An analysis of newspaper commentary and an interview with a representative from the Flood Control District of Maricopa County (FCDMC) indicated that there is a disconnect between public perception and the structure of FCDMC. Through this analysis a better understanding of the FCDMC as well as the impact of severe storm events in Maricopa County was found.
ContributorsBrancati, Olivia Anne (Author) / Vivoni, Enrique (Thesis director) / White, Dave (Committee member) / Civil, Environmental and Sustainable Engineering Programs (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Our thesis project, blanknationalpark.com, asked one question : how is climate change impacting National Parks in America? We decided to travel to three different areas: Joshua Tree, Glacier and Everglades National Park. It didn’t take long to discover that there was never a definitive answer. The effects of climate change looked different in every park we visited. Joshua Tree was struggling with changes in temperature, climate regime and an increase in fires. The U.S Geological Survey predicted that all of the glaciers in Glacier National Park could be gone by 2030. Everglades National Park was facing the constant threat of sea-level rise, invasive species and stronger hurricanes. However, in every park, one thing was certain - they all would not have their iconic features in the future due to climate change. For our thesis, we created blanknationalpark.com to emphasize the fact that Joshua Tree National Park won’t have Joshua Trees in the coming centuries, glaciers would cease to exist in Glacier National Park and the entire Everglades ecosystem itself will be underwater in the next century and a half. Thus, our project name, “Blank National Park”, pays tribute to the uncertainty of what these famous landscapes could look like in the future. Our main goal was to provide the public with a visual experience that is not only informative but engaging so that we could provide an educational experience about a critical situation without appearing too dismal. We chose to include our last page, ‘Solutions’, to establish hope for the future, and encourage people to take action to help preserve National Parks and the world we live in.
ContributorsCutler, Alison Jane (Co-author) / Nagaishi, Ayano (Co-author) / White, Dave (Thesis director) / Muench, Sarah (Committee member) / Walter Cronkite School of Journalism & Mass Comm (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
As inhabitants of a desert, a sustainable water source has always been and will continue to be a crucial component in developing the cities Arizonans call home. Phoenix and the surrounding municipalities make up a large metropolitan area that continues to grow in spatial size and population. However, as climate change becomes more of an evident challenge, Arizona is forced to plan and make decisions regarding its ability to safely and efficiently maintain its livelihood and/or growth. With the effects of climate change in mind, Arizona will need to continue to innovatively and proactively address issues of water management and the effects of urban heat island (UHI). The objective of this thesis was to study the socioeconomic impacts of four extreme scenarios of the future Phoenix metropolitan area. Each of the scenarios showcased a different hypothetical extreme and uniquely impacted factors related to water management and UHI. The four scenarios were a green city, desert city, expanded city into desert land, and expanded city into agricultural land. These four scenarios were designed to emphasize different aspects of the urban water-energy-population nexus, as the future of the Phoenix metropolitan area is dynamic. Primarily, the Green City and Desert City served as contrasting viewpoints on UHI and water sustainability. The Expanded Cities showed the influence of population growth and land use on water sustainability. The socioeconomic impacts of the four scenarios were then analyzed. The quantitative data of the report was completed using the online user interface of WaterSim 5.0 (a program created by the Decision Center for a Desert City (DCDC) at Arizona State University). The different scenarios were modeled in the program by adjusting various demand and supply oriented factors. The qualitative portion as well as additional quantitative data was acquired through an extensive literature review. It was found that changing land use has direct water use implications; agricultural land overtaken for municipal uses can sustain a population for longer. Though, removing agricultural lands has both social and economic implications, and can actually cause the elimination of an emergency source. Moreover, it was found that outdoor water use and reclaimed wastewater can impact water sustainability. Practices that decrease outdoor water use and increase wastewater reclamation are currently occurring; however, these practices could be augmented. Both practices require changes in the publics' opinions on water use, nevertheless, the technology and policy exists and can be intensified to become more water sustainable. While the scenarios studied were hypothetical cases of the future of the Phoenix metropolitan area, they identified important circumscribing measures and practices that influence the Valley's water resources.
ContributorsVon Gnechten, Rachel Marie (Author) / Wang, Zhihua (Thesis director) / White, Dave (Committee member) / Civil, Environmental and Sustainable Engineering Programs (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
Traditional Reinforcement Learning (RL) assumes to learn policies with respect to reward available from the environment but sometimes learning in a complex domain requires wisdom which comes from a wide range of experience. In behavior based robotics, it is observed that a complex behavior can be described by a combination of simpler behaviors. It is tempting to apply similar idea such that simpler behaviors can be combined in a meaningful way to tailor the complex combination. Such an approach would enable faster learning and modular design of behaviors. Complex behaviors can be combined with other behaviors to create even more advanced behaviors resulting in a rich set of possibilities. Similar to RL, combined behavior can keep evolving by interacting with the environment. The requirement of this method is to specify a reasonable set of simple behaviors. In this research, I present an algorithm that aims at combining behavior such that the resulting behavior has characteristics of each individual behavior. This approach has been inspired by behavior based robotics, such as the subsumption architecture and motor schema-based design. The combination algorithm outputs n weights to combine behaviors linearly. The weights are state dependent and change dynamically at every step in an episode. This idea is tested on discrete and continuous environments like OpenAI’s “Lunar Lander” and “Biped Walker”. Results are compared with related domains like Multi-objective RL, Hierarchical RL, Transfer learning, and basic RL. It is observed that the combination of behaviors is a novel way of learning which helps the agent achieve required characteristics. A combination is learned for a given state and so the agent is able to learn faster in an efficient manner compared to other similar approaches. Agent beautifully demonstrates characteristics of multiple behaviors which helps the agent to learn and adapt to the environment. Future directions are also suggested as possible extensions to this research.
ContributorsVora, Kevin Jatin (Author) / Zhang, Yu (Thesis advisor) / Yang, Yezhou (Committee member) / Praharaj, Sarbeswar (Committee member) / Arizona State University (Publisher)
Created2021