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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- All Subjects: Biology
- Creators: McGraw, Kevin J
- Creators: Robert, Jason
Description
This study aims to unearth monological and monocultural discourses buried under the power of the dominant biomedical model governing the HIV/AIDS debate. The study responds to an apparent consensus, rooted in Western biomedicine and its "standardizations of knowledge," in the production of the current HIV/AIDS discourse, especially in Sub-Saharan Africa. As a result, biomedicine has become the dominant actor (in) writing and rewriting discourse for the masses while marginalizing other forms of medical knowledge. Specifically, in its development, the Western biomedical model has arguably isolated the disease from its human host and the social experiences that facilitate the disease's transmission, placing it in the realm of laboratories and scientific experts and giving full ownership to Western medical discourse. Coupled with Western assumptions about African culture that reproduce a one-sided discourse informing the social construction of HIV/AIDS in Africa, this Western monopoly thus constrained the extent and efficacy of international prevention efforts. In this context, the goal for this study is not to demonize the West and biomedicine in general. Rather, this study seeks an alternative and less monolithic understanding currently absent in scientific discourses of HIV/AIDS that frequently elevates Western biomedicine over indigenous medicine; the Western expert over the local. The study takes into account the local voices of Sub-Saharan Africa and how the system has affected them, this study utilizes a Foucauldian approach to analyze discourse as a way to explore how certain ways of knowledge are formed in relation to power. This study also examines how certain knowlege is maintaned and reinforced within specific discourses.
ContributorsAbdalla, Mohamed (Author) / Jacobs, Bertram (Thesis advisor) / Robert, Jason (Committee member) / Klimek, Barbara (Committee member) / Arizona State University (Publisher)
Created2014
Description
Prior to the first successful allogeneic organ transplantation in 1954, virtually every attempt at transplanting organs in humans had resulted in death, and understanding the role of the immune mechanisms that induced graft rejection served as one of the biggest obstacles impeding its success. While the eventual achievement of organ transplantation is touted as one of the most important success stories in modern medicine, there still remains a physiological need for immunosuppression in order to make organ transplantation work. One such solution in the field of experimental regenerative medicine is interspecies blastocyst complementation, a means of growing patient-specific human organs within animals. To address the progression of immune-related constraints on organ transplantation, the first part of this thesis contains a historical analysis tracing early transplant motivations and the events that led to the discoveries broadly related to tolerance, rejection, and compatibility. Despite the advancement of those concepts over time, this early history shows that immunosuppression was one of the earliest limiting barriers to successful organ transplantation, and remains one of the most significant technical challenges. Then, the second part of this thesis determines the extent at which interspecies blastocyst complementation could satisfy modern technical limitations of organ transplantation. Demonstrated in 2010, this process involves using human progenitor cells derived from induced pluripotent stem cells (iPSCs) to manipulate an animal blastocyst genetically modified to lack one or more functional genes responsible for the development of the intended organ. Instead of directly modulating the immune response, the use of iPSCs with interspecies blastocyst complementation could theoretically eliminate the need for immunosuppression entirely based on the establishment of tolerance and elimination of rejection, while also satisfying the logistical demands imposed by the national organ shortage. Although the technology will require some further refinement, it remains a promising solution to eliminate the requirement of immunosuppression after an organ transplant.
ContributorsDarby, Alexis Renee (Author) / Maienschein, Jane (Thesis advisor) / Robert, Jason (Thesis advisor) / Ellison, Karin (Committee member) / Arizona State University (Publisher)
Created2020
Description
This thesis reviews the initial cases of fetal surgery to correct myelomeningocele, a severe form of spina bifida, and discusses the human and social dimensions of the procedure. Myelomeningocele is a fetal anomaly that forms from improper closure of the spinal cord and the tissues that surround it. Physicians perform fetal surgery on a developing fetus, while it is in the womb, to mitigate its impacts. Fetal surgery to correct this condition was first performed experimentally in the mid-1990and as of 2020, it is commonly performed. The initial cases illuminated important human and social dimensions of the technique, including physical risks, psychological dimensions, physician bias, and religious convictions, which affect decision-making concerning this fetal surgery. Enduring questions remain in 2020. The driving question for this thesis is: given those human and social dimensions that surround fetal surgery to correct myelomeningocele, whether and when is the surgery justified? This thesis shows that more research is needed to answer or clarify this question.
ContributorsEllis, Brianna (Author) / Maienschein, Jane (Thesis advisor) / Ellison, Karin (Thesis advisor) / Robert, Jason (Committee member) / Arizona State University (Publisher)
Created2020
Description
The control, function, and evolution of sleep in animals has received little attention compared to many other fitness-relevant animal behaviors. Though natural selection has largely been thought of as the driving evolutionary force shaping sleep biology, sexual and social selection may also have transformative effects on sleep quantity and quality in animals. An overarching hypothesis is that increased levels of investment into inter-sexual choice and intra-sexual competition will reduce sleep. An alternative hypothesis is that sexual ornamentation (e.g. avian plumage coloration and song) may have evolved to communicate sleep health and may therefore be positively related to sleep investment. In this dissertation, I studied how sleep is related to components of sexual and social selection in animals (mostly in birds). I first reviewed the literature for empirical examples of how social and sexual selection drive animal sleep patterns and found support for this relationship in some common types of inter-individual interactions (e.g. mating, intra-sexual competition, parent-offspring interactions, group interactions); I also provided new ideas and hypotheses for future research. I then tested associations between sleep behavior with expression of ornaments (song and plumage coloration), using the house finch (Haemorhous mexicanus) as a model system. For both color and song, I found support for the hypothesis that individuals with exaggerated ornaments slept deeper and longer, suggesting that sleep is a critical resource for ornament elaboration and/or may be communicated by both types of sexual signal. Following this, I tested the phylogenetic association between sleep and social/sexual selection as well as other life-history traits across birds. I found that more territorial bird species sleep less, that polygynous birds sleep more than monogamous and polygynandrous birds, and that birds migrating longer distances sleep less and have less REM sleep. Finally, in the interest of applying basic knowledge about sleep biology to current global problems, I found support for the hypothesis that house finches from city environments have developed resilience to artificial light pollution at night. Altogether, I found that social, sexual, and life-history traits are indeed important and overlooked drivers of sleep behavior from multiple levels of analysis.
ContributorsHutton, Pierce (Author) / McGraw, Kevin J (Thesis advisor) / Rutowski, Ronald L (Committee member) / Deviche, Pierre J (Committee member) / Sweazea, Karen L (Committee member) / Lesku, John A (Committee member) / Arizona State University (Publisher)
Created2021
Description
Organisms regularly face the challenge of having to accumulate and allocate limited resources toward life-history traits. However, direct quantification of how resources are accumulated and allocated is rare. Carotenoids are among the best systems for investigating resource allocation, because they are diet-derived and multi-functional. Birds have been studied extensively with regard to carotenoid allocation towards life-history traits, but direct quantification of variation in carotenoid distribution on a whole-organism scale has yet to be done. Additionally, while we know that scavenger receptor B1 (SCARB1) is important for carotenoid absorption in birds, little is known about the factors that predict how SCARB1 is expressed in wild populations. For my dissertation, I first reviewed challenges associated with statistically analyzing tissue distributions of nutrients (nutrient profiles) and tested how tissue carotenoid distributions (carotenoid profiles) varied by sex, season, health state, and coloration in two bird species, house finches (Haemorhous mexicanus) and zebra finches (Taeniopygia guttata). Then, I investigated the relationship between dietary carotenoid availability, relative expression of SCARB1, and extent of carotenoid-based coloration in a comparative study of wood-warblers (Parulidae). In my review of studies analyzing nutrient profiles, I found that multivariate analyses were the most common, but studies rarely reported intercorrelations among nutrient types. In house finches, all tissue carotenoid profiles varied by sex, season, and coloration. For example, males during autumn (molt) had higher concentrations of 3-hydroxyechinenone (the major red carotenoid in sexually attractive male feathers) in most but not all tissues compared to other season and sex combinations. However, the relationship between color and carotenoid profiles depended on the color metric. In zebra finches, only muscle and spleen carotenoid profiles varied between immune-challenged and control birds. In wood-warblers, I found that capacity to absorb carotenoids was positively correlated with the evolution of carotenoid-based coloration but negatively associated with liver carotenoid accumulation. Altogether, my dissertation illustrates (a) the context-dependence of tissue carotenoid profile variation, (b) that carotenoid-based integumentary coloration is a reflection of tissue carotenoid profiles, and (c) that digestive physiology (e.g., carotenoid absorption) is an important consideration in the study of diet and coloration in wild birds.
ContributorsWebb, Emily (Author) / McGraw, Kevin J (Thesis advisor) / Deviche, Pierre (Committee member) / Martins, Emilia (Committee member) / Sweazea, Karen (Committee member) / Arizona State University (Publisher)
Created2021
Description
Speciation, or the process by which one population diverges into multiple populations that can no longer interbreed with each other, has brought about the incredible diversity of life. Mechanisms underlying this process can be more visible in the early stages of the speciation process. The mechanisms that restrict gene flow in highly mobile species with no absolute barriers to dispersal, especially marine species, are understudied. Similarly, human impacts are reshaping ecosystems globally, and we are only just beginning to understand the implications of these rapid changes on evolutionary processes. In this dissertation, I investigate patterns of speciation and evolution in two avian clades: a genus of widespread tropical seabirds (boobies, genus Sula), and two congeneric passerine species in an urban environment (cardinals, genus Cardinalis). First, I explore the prevalence of gene flow across land barriers within species and between sympatric species in boobies. I found widespread evidence of gene flow over all land barriers and between 3 species pairs. Next, I compared the effects of urbanization on the spatial distributions of two cardinal species, pyrrhuloxia (Cardinalis sinuatus) and northern cardinals (Cardinalis cardinalis), in Tucson, Arizona. I found that urbanization has different effects on the spatial distributions of two closely related species that share a similar environmental niche, and I identified environmental variables that might be driving this difference. Then I tested for effects of urbanization on color and size traits of these two cardinal species. In both of these species, urbanization has altered traits involved in signaling, heat tolerance, foraging, and maneuverability. Finally, I tested for evidence of selection on the urban populations of both cardinal species and found evidence of both parallel selection and introgression between the species, as well as selection on different genes in each species. The functions of the genes that experienced positive selection suggest that light at night, energetics, and air pollution may have acted as strong selective pressures on these species in the past. Overall, my dissertation emphasizes the role of introgression in the speciation process, identifies environmental stressors faced by wildlife in urban environments, and characterizes their evolutionary responses to those stressors.
ContributorsJackson, Daniel Nelson (Author) / McGraw, Kevin J (Thesis advisor) / Amdam, Gro (Committee member) / Sweazea, Karen (Committee member) / Taylor, Scott (Committee member) / Arizona State University (Publisher)
Created2023