VictorJuiz/thesis huggingface dataset:
Water Quality and Quantity in Intermittent and Continuous Piped Water Supplies in Hubli-Dharwad, India

In at least 45 low- and middle-income countries, piped water systems deliver water for limited durations. Few data are available of the impact of intermittent water supply (IWS) on the water quality and quantity delivered to households. This thesis examines the impact of intermittently supplied piped water on the quality and quantity of water delivered to residential taps in Hubli-Dharwad, India, when compared to continuous piped water supply. A framework for understanding the pathways through which IWS can impact water quality is first developed. The extent to which contamination occurs in Hubli-Dharwad is quantified by comparing microbial water quality throughout the distribution system in an intermittent system and a continuous system in the same city. The mechanisms affecting water quality in the IWS network in Hubli-Dharwad are identified by measuring changes in water quality over time using continuous measurements from pressure and physico-chemical sensors paired with grab samples tested for indicator bacteria. In the final chapter, a new method of measuring household water consumption in an IWS when supply durations are limited and few metered data are available is developed. This thesis showed that the intermittent supply was frequently subject to contamination in the distribution system and that households with intermittent supply consumed limited quantities of water. While these results demonstrated that converting to a continuous water supply can improve water quality when compared to intermittent supply, this conversion may not be possible in the near future for resource-constrained towns and cities. This thesis contributes to knowledge of the mechanisms causing contamination and constricting water access in IWS systems, which can help improve systems to ensure that people with piped water receive water that is reliable, safe, and sufficient.

Advisor: Nelson, Kara L
The (Non) Regulation of Endocrine Disrupting Chemicals

This dissertation investigates efforts in the United States to regulate endocrine-disrupting chemicals. 1n 1996, Congress mandated the U.S. Environmental Protection Agency to establish a screening program for chemicals that appeared to interfere with the actions of estrogens, androgens and thyroid hormones; no chemicals have yet proceeded through the full complement of assays, and many details of the program remain unresolved. Moreover, much is still unknown about endocrine-disrupting chemicals, complicating the tasks of assessing and regulating them; for example, there is significant scientific support for the notion that they can exert effects at very low-doses, but industry disputes such findings. Without an effective Endocrine Disruptor Screening Program (EDSP), human and wildlife population continue to be exposed to possible endocrine-disruptors, with long-term consequences that remain unclear./n/nThis dissertation examines how industry stakeholders, non-governmental organizations and others have framed the scientific issues and sought to influence regulators, consumers and other audiences, through public comment, ex parte meetings and media coverage. It examines: 1) public comments from stakeholders in response to the first draft list of chemicals for the EDSP; 2) private meetings between industry representatives and the EPA about key aspects of the EDSP; and 3) news coverage of phthalates, and in particular advocacy efforts to raise awareness about their presence in brand-name consumer goods./nThe results of this investigation suggest that while industry stakeholders might not appear to have significant impact on the content of rules, the regulatory process has nonetheless provided them with multiple opportunities to delay the process of EDSP development. The results also suggest that environmental and public health advocates can find different strategies for effecting policy change, with the news media playing a key role. In particular, offering new forms of evidence and altering public perceptions about the potential hazards of everyday consumer products can exert pressure on corporations to change behaviors and reformulate products, and on politicians to take legislative action against particularly worrisome chemicals. The trade-off is that the benefits might be far narrower in scope--as in this particular case, limited to phthalates in toys and personal care products--than the protections envisioned as part of an overarching structure like the EDSP.

Advisor: Morello-Frosch, Rachel
Incentives and Strategic Choices In The Secretary Problem

Optimal policies for various secretary problems have an undesirable trait: they would interview applicants for the position, but those earlier ones are guaranteed to not get selected. Therefore, early applicants have incentive to not come in for their scheduled interviews, and as a direct consequence, the employer's intention to learn from the population becomes useless. Prior works have been done that tried to mitigate this issue, where the employer sacrifices her overall probability of selecting the best applicant by assigning equal selection probability to all interview slots. Among our results, we show such approaches can be costly for an employer with objectives different from the classical one. Furthermore, we generalize the classical setting to allow applicants to make independent choices with regard to their time of availability. This new game-theoretic approach solves the interviewing-without-hiring problem that arose earlier, and surprisingly, improves the employer's probability of selecting the best applicant from one obtained in the classical setting.

Advisor: Adler, Ilan
Expanding the scope of organofluorine biochemistry through the study of natural and engineered systems

Fluorination has become a very useful tool in the design and optimization of bioactive small molecules ranging from pesticides to pharmaceuticals. Its small size allows a sterically conservative substitution for a hydrogen or hydroxyl, thus maintaining the overall size and shape of a molecule. However, the extreme electronegativity of fluorine can dramatically alter other properties of the molecule. As a result, the development of new methods for fluorine incorporation is currently a major focus in synthetic chemistry. It is our goal to use a complementary biosynthetic approach to use enzymes for the regio-selective incorporation of fluorine into complex natural product scaffolds through the fluoroacetate building block./nTowards this goal, we initiated a study of the only known genetic host of a carbon-fluorine bond forming enzyme, the fluoroacetate- and fluorothreonine-producing bacterium Streptomyces cattleya. Sequencing and analysis of the genome identified several paralogs of enzymes predicted to be on the fluoroacetate and fluorothreonine biosynthetic pathway and whose function were probed by in vitro biochemistry and genetic knock-out studies. We sought to further explore how S. cattleya manages fluoroacetate, which is a potential biosynthetic building block but is also a potent toxin that operates by shutting down the tricarboxylic acid (TCA) cycle. Coordinated transcriptional changes of genes involved in central metabolism and organofluorine metabolism suggest transcriptional control may serve as the major mechanism for management of fluoroacetate toxicity. This hypothesis is further supported by biochemical analysis of S. cattleya enzymes involved in fluoroacetate toxicity, which showed that they were no more selective against fluorine than orthologs from non-producing bacteria./nTo explore the possibility of incorporating fluorinated building blocks into more complex natural products, we turned to type I polyketide synthases as their modular assembly line nature would make them ideal candidates for the engineering of site-selective incorporation of fluorinated subunits. We first developed methods to enzymatically synthesize fluoromalonyl-CoA, which is a fluorinated congener of the malonyl-CoA extender unit. With this building block in hand, we were able to observe incorporation of fluorine into a triketide polyketide. We then showed that it is possible to site-selectively incorporate fluorine into tetraketide products. These results suggest that the production of complex fluorinated natural products is possible and may allow us to explore the medicinal chemistry of these compounds using site-selective fluorination.

Advisor: Chang, Michelle C.Y.
Process Flexibility Design in Unbalanced and Asymmetric Networks

In a multi-product multi-plant manufacturing system, process flexibility is both the abil- ity of each plant to produce a variety of products and the ability to produce products at multiple plants. A balanced network has the same number of plants and products. In a symmetric network, all the plants have the same capacity and all the products have the same demand. Several design guidelines and flexibility indices have been developed in the literature to inform the design of flexible production networks. Yet little insights have been gained in unbalanced networks and asymmetric networks. In this thesis, we aim to provide new insights and results of unbalanced and asymmetric networks./nFirst, we propose additional flexibility design guidelines by refining the well-known Chain- ing Guidelines (Jordan and Graves, 1995). We study unbalanced and symmetric networks where each product is built at two plants. We also briefly discuss cases where (1) each product is built at three plants and (2) some products are built at only one plant. An ex- tensive computational study suggests that our refinements work very well for finding flexible configurations with minimum shortfall./nThen, instead of assuming a joint demand distribution for all products, we optimize the worst case over all the demand joint distributions that have the given marginal mean and variance. We present two results. First, we show that most known results for the effects of plant capacity and product demand in symmetric networks can be extended to asymmetric networks. Second, the analysis sheds light on how to incorporate demand standard deviation into the existing flexibility design guidelines and indices. We show that the proposed method significantly enhances the performance of the Node Expansion Guideline.

Advisor: Shen, Zuojun
Quasi-Variational Inequalities for Source-Expanding Hele-Shaw Problems

We study nonlinear partial differential equations describing Hele-Shaw flows for which the source of the fluid, which classically is at a single point, instead expands as the moving boundary uncovers new sources. This problem is reformulated as a type of quasi- variational inequality, for which we show there exists a unique weak solution. Our procedure utilizes a Baiocchi integral transform. However, unlike in traditional applications, the inequality solved by the transformed variable continues to depend on the free boundary, and thus standard theory of variational inequalities cannot be immediately applied. Instead, we develop convergent time-stepping scheme. As a further application, we generalize and study a related problem with a growing density function obeying a hard constraint on the maximum density.

Advisor: Evans, Lawrence C.
Biotic and abiotic factors constraining the distribution and abundance of the rare mangrove Pelliciera rhizophorae in Panama

Pelliciera rhizophorae is a Neotropical mangrove species with a narrow geographic distribution. Despite having a wide fossil distribution around the Caribbean Sea, extant populations of P. rhizophorae are rare on the Caribbean coast of Central and South America. The current extent of the distribution of P. rhizophorae on the Caribbean coast of Panamá was investigated. Populations are small and isolated, with seven populations occurring on freshwater streams in Bocas del Toro and Colón provinces. A shadehouse experiment was conducted to test the shade and salinity tolerances of P. rhizophorae compared to three widespread mangrove species: Avicennia germinans, Rhizophora mangle, and Lumnitzera racemosa. Pelliciera rhizophorae is more sensitive to soil salinity and high light conditions than other, more common mangroves but its salinity tolerance does not explain its narrow distribution. Obstacles to recruitment for P. rhizophorae were examined by quantifying propagule predation by crabs and seedling survival in different forest types. Crab predation of P. rhizophorae propagules was much higher in mangrove forests where P. rhizophorae does not occur then where it does occur. Seedlings were planted that were protected from predation by crabs, and seedling survival did not differ between forest types, suggesting that crab predation limits recruitment in areas dominated by other mangrove species. Nutrient dynamics and biomass allocation ratios were studied in P. rhizophorae from populations on the Pacific and Caribbean coasts of Panamá. There are two growth forms that occur on each coast: a stunted "dwarf" form and a taller "fringe" form. In other species the stunted form is caused by nutrient limitation, but the nutrient status of P. rhizophorae had never been studied. Dwarf trees had lower nutrient content than fringe trees, and also allocated more biomass to stems than leaves relative to fringe trees. A combination of abiotic (e.g., shade availability) and biotic factors (e.g., propagule predation by crabs) are responsible for the narrow distribution of P. rhizophorae.

Advisor: Sousa, Wayne P
Gas Diffusion in Metals: Fundamental Study of Helium-Point Defect Interactions in Iron and Kinetics of Hydrogen Desorption from Zirconium Hydride

The behavior of gaseous foreign species (e.g., helium and hydrogen), which are either generated, adsorbed or implanted within the structural materials (e.g., iron and zirconium) exposed to irradiation environments, is an important and largely unsolved topic, as they intensively interact with the irradiation-induced defects, or bond with the lattice atoms to form new compounds, and impose significant effects on their microstructural and mechanical properties in fission and fusion reactors. This research investigates two cases of gas diffusion in metals (i.e., the helium-point defect interactions in iron and kinetics of hydrogen desorption from zirconium hydride) through extensive experimental and modeling studies, with the objective of improving the understanding of helium effects on the microstructures of iron under irradiation and demonstrating the kinetics of hydrogen diffusion and precipitation behavior in zirconium that are crucial to predict cladding failures and hydride fuel performance./nThe study of helium effects in structural materials aims to develop a self-consistent, experimentally validated model of helium - point defect, defect cluster and intrinsic defects through detailed inter-comparisons between experimental measurements on helium ion implanted iron single crystals and computational models. The combination of thermal helium desorption spectrometry (THDS) experiment with the cluster dynamic model helps to reveal the influence of impurities on the energetics and kinetics of the He-defect interactions and to realize the identification of possible mechanisms governing helium desorption peaks. Positron annihilation spectroscopy is employed to acquire additional information on He-vacancy cluster evolution, which provides an opportunity to validate the model qualitatively. The inclusion of He - self-interstitial clusters extends the cluster dynamic model while MD simulations explore the effects of dislocation loops on helium clustering. In addition, the influence of pre-existing defects on helium behavior in iron is studied by applying a hybrid model, which includes the defect evolution during neutron irradiation and the subsequent He ion implantation and THDS. These modeling predictions will be assessed in future experiments./nThe hydrogen desorption process from zirconium hydride and zirconium in vacuum is also studied by coordinated experimental and modeling methods. The production and verification of the desired δ-zirconium hydride is discussed while thermal desorption spectroscopy (TDS) is employed to obtain the hydrogen desorption spectra directly. In addition, a one-dimensional two-phase moving boundary model coupled with a kinetic description of hydrogen desorption from a two-phase region of δ-ZrH1.6±n and α-Zr is developed to compare with the TDS experimental results.

Advisor: Wirth, Brian D
Hopfield nets : Novel Uses in Neuroscience and Machine Learning

Hopfield nets are among the most commonly used models in machine learning and neuroscience today. In this thesis I explore two novel ways of applying this model in two different areas--Cognitive science and Machine Learning. In the first part of this thesis we motivate, derive, and specify a new model of the control processes that reconfigure mental resources for a change of task. We apply this new model to the hundred year old Stroop paradigm, and find that it uses fewer free parameters than other models that account for a similarly broad set of experimental results. In the second part of this thesis we introduce a novel model for solving a short-coming of the Hopfield Net: lack of recognition for memories that have been translated, rotated, or otherwise transformed. Taking inspiration from Arathorn's map seeking circuit approach, we develop a model that partially overcomes this hurdle, and outperforms current popular models in certain high-noise regimes.

Advisor: Deweese, Michael R
Toward a Culture of Tribal Power: The Promise and Power of Culture in Development and Nation Building in the Hoopa Nation

The dissertation examines cultural projects and economic development enterprises to explore the power and potential power that culture has in informing, guiding and improving community and economic development efforts in the Hoopa Nation of Northern California. The unique political standing of Native American tribes as "domestic dependent nations," coupled with federal devolution policies of the 1970s and 1980s, opened opportunities for Native Nations to pursue tribally-directed economic development projects. After decades of failed federal policies, many Native Nations have achieved modest to remarkable success. Despite the compelling nature of these relatively astonishing success stories, these cases remain absent from key development literatures, including urban planning and international development. The absence offers an opportunity for a close examination of a number of key concerns including 1) what tribes are doing right; 2) the key components of this success; 3) whether, how and where these are replicable; and 4) how these practices might inform urban development and planning theory. These broader concerns frame this study, which examines the relationship between culture and community and economic development in a Native American context. Drawing from a series of interviews with tribal leaders, development practitioners, business leaders, and tribal enterprise managers, it explores the ways in which the conceptualizations, discourses, and practices of Hupa culture have the potential to inform and shape development projects and the ways in which these practices provide for greater efficacy. The research aims to show the concrete ways in which "culture" can be an effective input for development, a mobilizing discourse, and is often both a means and an end to development goals. Building on the work of Native Nation Building scholars, the study offers insights into methodologies for operationalizing cultural information in community and economic development.

Advisor: Hutson, Malo A
Institutional Heterogeneity in American Public Education: Theory, History, and Applications

Over the course of the last fifty years, public education in the United States has seen significant institutional change. Accountability systems have altered evaluative control moving the basis from structural conformity and process controls to output measures. Charter school laws have created a new organizational sector of publicly funded schools directly overseen by new organizational actors where instrumental decision making is decentralized and the degree of autonomy from district administrative structures, state regulations, and collective bargaining bodies are variable. The creation of new alternative routes of teacher recruitment and certification has deteriorated the stable arrangements between universities, unions, and districts that governed teacher training and employment. I argue that these changes have put strain on the ability of the dominant neoinstitutionalist perspective in organization theory as it's been applied to the sociology of education. The goals of this dissertation are threefold. First, I provide a foundation for an integration of neoinstitutionalist, resource dependence, and population ecology perspectives into a framework for the analysis of organizational behavior in the field of education. Second, I provide a broad institutional history of the key changes mentioned above. Finally, I explore two key research questions the stem from this theoretical and historical work./nChapter 1 outlines the dissertation as a whole. Chapter 2 critiques neoinstitutionalist approaches and takes steps to outline a basic theoretical approach integrating insights from other key organizational perspectives. In chapter 3 I outline the essentials of the new landscape of schooling. In chapter 4 I offer an institutional history of the key changes in the system of public education showing how they've changed the environments faced by schools and districts. In chapter 5 I examine the inter-organizational processes shaping the adoption and growth of charter schools in California. In chapter 6, I move to the individual level to examine how the organizational diversification spurred by the growth of charter schools impacts the movement of students between schools in a large urban school district. I conclude by discussing heterogeneity in the landscape of American public schooling with regard to the expansion of the charter school sector, describe recent changes in federal accountability, and discuss the need for research with a new theoretical orientation in the sociology of education.

Advisor: Fligstein, Neil