ASU Electronic Theses and Dissertations
This collection includes most of the ASU Theses and Dissertations from 2011 to present. ASU Theses and Dissertations are available in downloadable PDF format; however, a small percentage of items are under embargo. Information about the dissertations/theses includes degree information, committee members, an abstract, supporting data or media.
In addition to the electronic theses found in the ASU Digital Repository, ASU Theses and Dissertations can be found in the ASU Library Catalog.
Dissertations and Theses granted by Arizona State University are archived and made available through a joint effort of the ASU Graduate College and the ASU Libraries. For more information or questions about this collection contact or visit the Digital Repository ETD Library Guide or contact the ASU Graduate College at gradformat@asu.edu.
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The desire to start a family is something millions of people around the globe strive to achieve. However, many factors such as the societal changes in family planning due to increasing maternal age, use of birth control, and ever-changing lifestyles have increased the number of infertility cases seen in the United States each year. Infertility can manifest as a prolonged inability to conceive, or inability to carry a pregnancy full-term. Modern advancements in the field of reproductive medicine have begun to promote the use of Assisted Reproductive Technologies (ART) to circumvent reduced fertility in both men and women. Implementation of techniques such as In Vitro Fertilization, Intracytoplasmic Sperm Injection, and Pre-Implantation Genetic Testing have allowed many couples to conceive. There is continual effort being made towards developing more effective and personalized fertility treatments. This often begins in the form of animal research—a fundamental step in biomedical research. This dissertation examines infertility as a medical condition through the characterization of normal reproductive anatomy and physiology in the introductory overview of reproduction. Specific pathologies of male and female-factor infertility are described, which necessitates the use of ARTs. The various forms of ARTs currently utilized in a clinical setting are addressed including history, preparations, and protocols for each technology. To promote continual advancement of the field, both animal studies and human trials provide fundamental stepping-stones towards the execution of new techniques and protocols. Examples of research conducted for the betterment of human reproductive medicine are explored, including an animal study conducted in mice exploring the role of tyramine in ovulation. With the development and implementation of new technologies and protocols in the field, this also unearths ethical dilemmas that further complicate the addition of new technologies in the field. Combining an extensive review in assisted reproduction, research and clinical fieldwork, this study investigates the history and development of novel research conducted in reproductive medicine and explores the broader implications of new technologies in the field.
ContributorsPeck, Shelbi Marie (Author) / Baluch, Debra P (Thesis advisor) / Maienschein, Jane (Thesis advisor) / Sweazea, Karen (Committee member) / Ellison, Karin (Committee member) / Arizona State University (Publisher)
Created2021
Description
Eusocial insect colonies have often been imagined as “superorganisms” exhibiting tight homeostasis at the colony level. However, colonies lack the tight spatial and organizational integration that many multicellular, unitary organisms exhibit. Precise regulation requires rapid feedback, which is often not possible when nestmates are distributed across space, making decisions asynchronously. Thus, one should expect poorer regulation in superorganisms than unitary organisms.Here, I investigate aspects of regulation in collective foraging behaviors that involve both slow and rapid feedback processes. In Chapter 2, I examine a tightly coupled system with near-instantaneous signaling: teams of weaver ants cooperating to transport massive prey items back to their nest. I discover that over an extreme range of scenarios—even up vertical surfaces—the efficiency per transporter remains constant. My results suggest that weaver ant colonies are maximizing their total intake rate by regulating the allocation of transporters among loads. This is an exception that “proves the rule;” the ant teams are recapitulating the physical integration of unitary organisms.
Next, I focus on a process with greater informational constraints, with loose temporal and spatial integration. In Chapter 3, I measure the ability of solitarily foraging Ectatomma ruidum colonies to balance their collection of protein and carbohydrates given different nutritional environments. Previous research has found that ant species can precisely collect a near-constant ratio between these two macronutrients, but I discover these studies were using flawed statistical approaches. By developing a quantitative measure of regulatory effect size, I show that colonies of E. ruidum are relatively insensitive to small differences in food source nutritional content, contrary to previously published claims.
In Chapter 4, I design an automated, micro-RFID ant tracking system to investigate how the foraging behavior of individuals integrates into colony-level nutrient collection. I discover that spatial fidelity to food resources, not individual specialization on particular nutrient types, best predicts individual forager behavior. These findings contradict previously published experiments that did not use rigorous quantitative measures of specialization and confounded the effects of task type and resource location.
ContributorsBurchill, Andrew Taylor (Author) / Pavlic, Theodore P (Thesis advisor) / Pratt, Stephen C (Thesis advisor) / Hölldobler, Bert (Committee member) / Cease, Arianne (Committee member) / Berman, Spring (Committee member) / Arizona State University (Publisher)
Created2022
Description
Programmed cell death plays an important role in a variety of processes that promote the survival of the host organism. Necroptosis, a form of programmed cell death, occurs through a signaling pathway involving receptor-interacting serine-threonine protein kinase 3 (RIPK3). In response to vaccinia virus infection, necroptosis is induced through DNA-induced activator of interferon (DAI), which activates RIPK3, leading to death of the cell and thereby inhibiting further viral replication in host cells. DAI also localizes into stress granules, accumulations of mRNAs that have stalled in translation due to cellular stress. The toxin arsenite, a canonical inducer of stress granule formation, was used in this project to study necroptosis. By initiating necroptosis with arsenite and vaccinia virus, this research project investigated the roles of necroptosis proteins and their potential localization into stress granules. The two aims of this research project were to determine whether stress granules are important for arsenite- and virus-induced necroptosis, and whether the proteins DAI and RIPK3 localize into stress granules. The first aim was investigated by establishing a DAI and RIPK3 expression system in U2OS cells; arsenite treatment or vaccinia virus infection was then performed on the U2OS cells as well as on U2OSΔΔG3BP1/2 cells, which are not able to form stress granules. The second aim was carried out by designing fluorescent tagging for the necroptosis proteins in order to visualize protein localization with fluorescent microscopy. The results show that arsenite induces DAI-dependent necroptosis in U2OS cells and that this arsenite-induced necroptosis likely requires stress granules. In addition, the results show that vaccinia virus induces DAI-dependent necroptosis that also likely requires stress granules in U2OS cells. Furthermore, a fluorescent RIPK3 construct was created that will allowfor future studies on protein localization during necroptosis and can be used to answer questions regarding localization of necroptosis proteins into stress granules. This project therefore contributes to a greater understanding of the roles of DAI and RIPK3 in necroptosis, as well as the roles of stress granules in necroptosis, both of which are important in research regarding viral infection and cellular stress.
ContributorsGogerty, Carolina (Author) / Jacobs, Bertram (Thesis advisor) / Langland, Jeffrey (Committee member) / Jentarra, Garilyn (Committee member) / Arizona State University (Publisher)
Created2021
Description
Widening economic inequality has been identified as a moral challenge that constitutes a global impediment to socioeconomic well-being. While incongruities exist within any dynamic system, a sustained unequal value distribution can lead to social and economic obstructions for individuals and communities. Entrepreneurship has been identified as a force for good and subsequently funded as an institutional methodology to disburse well-being by democratizing economic empowerment. Current popular approaches are institutionalized in wealthier Western contexts, encapsulated in linear narratives, and aggressively exported to new, foreign environments. Due to the often-unrecognized philosophical assumptions underlying these narratives, current approaches tend to limit the benefits of entrepreneurship to specific audiences and position the promoting institutions as entrepreneurial imperialists, creating an economic hegemony as they reinforce current power dynamics and save the most valuable entrepreneurial exchanges for those with access and resources, often benefiting the institutions economically.
While much has been written on removing the impediments to current entrepreneurial approaches, this dissertation prioritizes practical utility by proposing the need for a refreshed philosophical approach, a new entrepreneurial narrative, and dynamic institutional networks that prioritize autonomy towards more effectively engaging a favorite of current entrepreneurial narratives: the rising generation.
ContributorsByrne, Jared (Author) / Maynard, Andrew (Thesis advisor) / Berman, Nina (Committee member) / Bowman, Diana (Committee member) / Semadeni, Matthew (Committee member) / Arizona State University (Publisher)
Created2024
Description
Contraceptives are a vital part of reproductive care by preventing unwanted pregnancy, providing relief to premenstrual syndrome or PMS symptoms, and more. Birth control has been around for many centuries and has given women autonomy over their reproductive health. The Griswold v. Connecticut Supreme Court case in 1965 was the first ruling that made birth control accessible to the public under the law. However, this ruling only pertained only to married couples until the Eisenstadt v. Baird case in 1972. That case gave single women the ability to legally purchase contraceptives for themselves. In the decades since those rulings, many laws and policies have been put into place to give those in lower-income areas the ability to purchase contraceptives as well. With this increase in accessibility, those who use contraceptives, or are thinking of starting birth control, need to understand how to use it, when to use it, and the effects of using contraceptives. In the United States, nurses outnumber doctors by a 4:1 ratio and spend more time with patients than anyone else in a clinic or hospital environment. Nurses, being the main healthcare providers with whom a patient will interact, often are the ones patients ask questions about care and overall advice. Nurses must be able to relay valuable information about treatments or medicines, such as birth control, and give accurate information on the effects such treatments have. Nursing students need to be prepared. However, the amount of information provided, and opinions given might be affected by their nursing education, past experiences with birth control, and more. This project surveys nursing students at Arizona State University on their attitudes, behaviors, and beliefs towards birth control interventions, and how their individual experiences and education influence these perceptions.
ContributorsHiggins, Ilani Elyce (Author) / Gur-Arie, Rachel (Thesis advisor) / Ellison, Karin (Thesis advisor) / Maienschein, Jane (Committee member) / Arizona State University (Publisher)
Created2024
Description
A central concern for modern macroeconomics is incorporating and understanding worker heterogeneity. The following two essays explore labor market dynamics along the dimensions of worker heterogeneity, search frictions, and policy. In each essay, I construct a macroeconomic model of the labor market, calibrate the model using micro data, and use the model to interpret labor market outcomes and evaluate policy. In the first chapter, I build an equilibrium lifecycle model of wages in which heterogeneous workers endogenously invest in human capital accumulation and on-the-job search effort while firms post jobs. I discipline the model using microdata from the Survey of Income and Program Participation. The calibrated model shows that on-the-job search drives lifecycle wage growth while heterogeneous human capital accumulation drives lifecycle wage dispersion. Then, I use the model as a laboratory to study the effects of tax and transfer progressivity. An increase in progressivity decreases wages, primarily due to reduced on-the-job search effort. Interactions between human capital, search, and job posting amplify the decrease in wages. Surprisingly, an increase in progressivity has little effect on wage dispersion because the effects from the human capital and search channels offset each other. The second chapter deals with the persistence of the unemployment rate over the business cycle. Standard search models contain little internal propagation and predict that, after shocks, the unemployment rate quickly converges to its steady state level. I show that duration dependence in unemployment (the fact that unemployed workers with longer unemployment spells are less likely to find jobs) helps explain the persistence of the unemployment rate. I embed duration dependence in an otherwise standard search model and show that it significantly increases the unemployment rate persistence, reconciling the model to the data. Intuitively, after recessions, the composition of the unemployment pool shifts to the long-term unemployed. Because of duration dependence, the long-term unemployed have lower job finding rates, and the shift in composition decreases the aggregate job finding rate, slowing recovery. The magnitude of the effect depends on the extent to which duration dependence is causal rather than a consequence of worker heterogeneity.
ContributorsMillington, Matthew John (Author) / Ferraro, Domenico (Thesis advisor) / Ventura, Gustavo (Committee member) / Chade, Hector (Committee member) / Arizona State University (Publisher)
Created2024
Description
Reactive oxygen species (ROS) including superoxide, hydrogen peroxide, and hydroxyl radicals occur naturally as a byproduct of aerobic respiration. To mitigate damages caused by ROS, Escherichia coli employs defenses including two cytosolic superoxide dismutases (SODs), which convert superoxide to hydrogen peroxide. Deletion of both sodA and sodB, the genes coding for the cytosolic SOD enzymes, results in a strain that is unable to grow on minimal medium without amino acid supplementation. Additionally, deletion of both cytosolic SOD enzymes in a background containing the relA1 allele, an inactive version of the relA gene that contributes to activation of stringent response by amino acid starvation, results in a strain that is unable to grow aerobically, even on rich medium. These observations point to a relationship between the stringent response and oxidative stress. To gain insight into this relationship, suppressors were isolated by growing the ∆sodAB relA1 cells aerobically on rich medium, and seven suppressors were further examined to characterize distinct colony sizes and temperature sensitivity phenotypes. In three of these suppressor-containing strains, the relA1 allele was successfully replaced by the wild type relA allele to allow further study in aerobic conditions. None of those three suppressors were found to increase tolerance to exogenous superoxides produced by paraquat, which shows that these mutations only overcome the superoxide buildup that naturally occurs from deletion of SODs. Because each of these suppressors had unique phenotypes, it is likely that they confer tolerance to SOD-dependent superoxide buildup by different mechanisms. Two of these three suppressors have been sent for whole-genome sequencing to identify the location of the suppressor mutation and determine the mechanism by which they confer superoxide tolerance.
ContributorsFlake, Melissa (Author) / Misra, Rajeev (Thesis advisor) / Shah, Dhara (Committee member) / Wang, Xuan (Committee member) / Arizona State University (Publisher)
Created2024
Description
There is increasing interest in growing strawberries (Fragaria ×ananassa) in indoor environments such as vertical farms, as the continued sustainability of outdoor
production is threatened due to reductions in arable land, labor shortages, and an
increased frequency of drought. However, the optimal conditions for growing
strawberries hydroponically in sole-source lighting conditions have yet to be established.
The objectives of this research were to investigate the optimal lighting conditions and
nutrient concentrations for strawberry production in vertical farming. In the first study,
bare-root plants of two strawberry cultivars, ‘Albion’ and ‘Monterey’, were grown in an
indoor vertical farm under a 22 °C air temperature and an 18-h photoperiod with 90
μmol·m−2·s−1 of blue light and 250 μmol·m−2·s−1 of red light with and without 50
μmol·m−2·s−1 of additional far-red light from light-emitting diodes. Adding far-red light
increased the fruit number per plant by 36%, total fruit fresh mass by 48%, and total
soluble solids content by 12% in ‘Albion’, but not ‘Monterey’. In the second study, bare
root plants of strawberries ‘Monterey’ and ‘San Andreas’ were grown under a 23 °C air
temperature and an 18-h photoperiod with an extended photosynthetic photon flux
density of 350 μmol·m−2·s−1. Plants were subjected to four potassium to nitrogen ratios
(K:N) of 1.5:1, 2.5:1, 3.5:1, and 4.5:1 in a deep-water culture hydroponic system.
Increasing K:N from 1.5:1 to 4.5:1 increased the root dry mass of ‘Monterey’, but
generally had little to no effect on vegetative growth in either cultivar. In addition, in
both cultivars, increasing K:N from 1.5:1 to 4.5:1 decreased individual fruit size and
increased titratable acidity. These results suggest that for indoor strawberry production,
including far-red light in sole-source lighting can improve fruit production in some
strawberry cultivars. However, increasing K:N in the hydroponic nutrient solution
generally does not benefit plant growth, fruit production, and fruit quality.
ContributorsRies, Jonathan (Author) / Park, Yujin (Thesis advisor) / Sagers, Cynthia (Committee member) / Meng, Qingwu (Committee member) / Arizona State University (Publisher)
Created2024
Description
The Northwest (NW) Atlantic porbeagle Lamna nasus is overfished and captured as bycatch in fisheries within the region. A comprehensive understanding of the population’s life history (e.g., reproduction) and habitat use, and the impact of capture with different gear types (e.g., post-release mortality) is needed to ensure effective fisheries management plans, develop bycatch mitigation strategies, and support stock recovery. This research used satellite tagging technologies to address gaps in knowledge needed to support management and conservation decisions for the NW Atlantic porbeagle. I provided the first estimate of post-release survival and recovery periods for immature porbeagles captured with rod-and-reel. Although survival was high (100%), juvenile porbeagles exhibited a recovery period in surface waters that may make them vulnerable to further fishing interactions. Next, I described the vertical habitat use of young porbeagles to recommend possible fishing modifications to reduce risk of capture. Young porbeagles spent more time in surface waters during summer compared to fall and during the night compared to day, suggesting that risk of capture may be reduced by setting gear deeper during summer and at night when this life stage’s behavior is reduced to the upper water column. Then, I provided an analysis of the seasonal and life stage-based habitat use of porbeagles. Space use was concentrated in continental shelf waters around Cape Cod, Massachusetts regardless of season and life stage. Given the relatively small and static high occupancy area overlaps with a high concentration of fishing activity, this region could be considered for spatial management of the NW Atlantic porbeagle. Finally, I used ultrasonography and satellite tagging to describe the three-dimensional habitat use of gravid porbeagles for the first time. Gravid porbeagles demonstrated seasonal differences in horizontal and vertical habitat use but spent most of the pupping season in waters southeast of Cape Cod or on Georges Bank, suggesting this region may be serving as a pupping ground for at least a portion of this population. Conservation efforts should focus on these important habitats to protect the next generation of porbeagles.
ContributorsAnderson, Brooke Nicole (Author) / Ferry, Lara (Thesis advisor) / Bowlby, Heather (Committee member) / Hammerschlag, Neil (Committee member) / Kang, Yun (Committee member) / Saul, Steven (Committee member) / Sulikowski, James (Committee member) / Arizona State University (Publisher)
Created2024
Description
This collection of essays attempts to address the question: what are the main driving forces of the recent changes in entrepreneurship and business dynamics in the US? In the first chapter, I examine changes within businesses in the US by showing that the share of value added by pass-through entities (sole proprietorships, partnerships, LLCs, and S-corporations) almost doubled while that of C-corporations has declined by one-forth. During this period, there have been notable changes in the tax structure and tax avoidance within these entities. I develop a dynamic growth model with endogenous tax avoidance, occupation choice, and uninsurable entrepreneurial risk to study the extent to which changes in taxation can account for the observed reallocation of output. My model results show that changes in tax structure account for 14 percent of the reallocation of output share observed in the US. I also find that the cumulative effect of changes in taxation, borrowing ability, and tax avoidance accounts for about 26 percent of the reallocation of output. In Chapter 2, I examine a different perspective on business dynamics by documenting the decline in business formation and entrepreneurship in the US. In fact, I document that entrepreneurship is more prevalent in married households and amongmen, and that these groups have undergone a greater decline in entrepreneurship since the 1980s. Additionally, I document that changes in the number of married households and the increase in female labor force participation account for over 40 percent of the overall fall in entrepreneurship in this period. To understand the relationship between demographic composition factors and entrepreneurship, I develop a model with an occupation choice for individuals of different marital status, college skills, and gender. The model takes into account important features of the data, including the extent of marital sorting, the skill premium, the gender wage gap, and the gender business income gap. My results indicate that changes in the demographic composition (share of married households, fraction of skilled individuals, marital sorting) account for 76% of the decline in entrepreneurship, 68.4% of the fall in married entrepreneurs, and 70.5% of the decrease in male entrepreneurs. Moreover, considering all changes account for 82.8% of the observed fall in entrepreneurship.
ContributorsDemir, Mehmet Tayyip (Author) / Ventura, Gustavo (Thesis advisor) / Vereshchagina, Galina (Committee member) / Ferraro, Domenico (Committee member) / Arizona State University (Publisher)
Created2024