Barrett, The Honors College Thesis/Creative Project Collection
Barrett, The Honors College at Arizona State University proudly showcases the work of undergraduate honors students by sharing this collection exclusively with the ASU community.
Barrett accepts high performing, academically engaged undergraduate students and works with them in collaboration with all of the other academic units at Arizona State University. All Barrett students complete a thesis or creative project which is an opportunity to explore an intellectual interest and produce an original piece of scholarly research. The thesis or creative project is supervised and defended in front of a faculty committee. Students are able to engage with professors who are nationally recognized in their fields and committed to working with honors students. Completing a Barrett thesis or creative project is an opportunity for undergraduate honors students to contribute to the ASU academic community in a meaningful way.
Displaying 1 - 3 of 3
Description
Wolbachia is a genus of obligately intracellular bacterial endosymbionts of arthropods and nematodes, infecting up to 66% of all such species. In order to ensure its transmission, it may modify host reproduction by inducing one of four phenotypes: cytoplasmic incompatibility, feminization of genetic males, killing of male embryos, and induction of thelytokous parthenogenesis. This investigation was a characterization of the so-far unexamined Wolbachia infection of Pogonomyrmex ants. Five main questions were addressed: whether Wolbachia infection rates vary between North and South America, whether infection rates are dependent on host range, whether Wolbachia affects the caste determination of P. barbatus, whether infection rates in Pogonomyrmex are similar to those of other ants, and whether Wolbachia phylogeny parallels the phylogeny of its Pogonomyrmex hosts. Using PCR amplification of the wsp, ftsZ, and gatB loci, Wolbachia infections were detected in four of fifteen Pogonomyrmex species (26.7%), providing the first known evidence of Wolbachia infection in this genus. All infected species were from South America, specifically Argentina. Therefore, Wolbachia has no role in the caste determination of the North American species P. barbatus. Additionally, while it appears that the incidence of Wolbachia in Pogonomyrmex may be limited to South America, host range did not correlate with infection status. The incidence of Wolbachia in Pogonomyrmex as a whole was similar to that of invasive Solenopsis and Linepithema species, but not to Wasmannia auropunctata or Anoplolepis gracilipes, which retain Wolbachia infection in non-native locations. This suggests that there may be a parallel in Wolbachia infection spread in certain short-term models of species colonization and long-term models of genus radiation. Finally, there was no congruity between host and parasite phylogeny according to maximum likelihood analyses, necessarily due to horizontal transfer of Wolbachia between hosts and lateral gene transfer between Wolbachia strains within hosts.
ContributorsHarris, Alexandre Marm (Author) / Gadau, Juergen (Thesis director) / Martin, Thomas (Committee member) / Helmkampf, Martin Erik (Committee member) / Barrett, The Honors College (Contributor) / Computer Science and Engineering Program (Contributor) / School of Life Sciences (Contributor)
Created2014-05
Description
This thesis was conducted in order to determine the role played by food miles metrics in making the agricultural industry more sustainable. In an effort to analyze the importance of eat locally this study utilizes a partial life cycle assessment. This study looks at oranges grown in Arizona and California and inputs such as water, energy, fertilizer, herbicide, pesticide, frost mitigation, and distance in order to conduct the partial life cycle assessment. Results of this study indicate that food miles are not as significant, in relation to overall energy input, as the locavore movement claims. This is because production processes account for a larger portion of the total energy used in the food chain than what these claims suggest. While eating locally is still a significant way of reducing energy use, this thesis shows that decisions about eating sustainably should not only focus on the distance that the products travel, but place equal, if not more, importance on energy use differences due to geographic location and in-farm operations. Future research should be completed with more comprehensive impact categories and conducted for different crops, farming, and locations. Further research is needed in order to confirm or challenge the results of this thesis. With more research conducted regarding this topic, ecological labeling of agricultural products could be improved to help consumers make the most informed choices possible.
ContributorsMaggass, Melissa Gail (Author) / Manuel-Navarrete, David (Thesis director) / Martin, Thomas (Committee member) / Barrett, The Honors College (Contributor) / School of Sustainability (Contributor) / W. P. Carey School of Business (Contributor) / Department of Management (Contributor)
Created2014-05
Description
There are three known materials that readily undergo fission, allowing their use as a base for nuclear fuel: uranium-235, a naturally-occurring but uncommon isotope; plutonium, created from irradiated natural uranium; and uranium-233, produced from thorium. Of the three, uranium-235 and plutonium feature heavily in the modern nuclear industry, while uranium-233 and the thorium fuel cycle have failed to have significant presence in the field. Historically, nuclear energy development in the United States, and thorium development in particular, has been tied to the predominant societal outlook on the field, and thorium was only pursued seriously as an option during a period when nuclear energy was heavily favored, and resources seemed scarce. Recently, thorium-based energy has been experiencing a revival in interest in response to pollution concerns regarding fossil fuels. While public opinion is still wary of uranium, thorium-based designs could reduce reliance on fossil fuels while avoiding traditional drawbacks of nuclear energy. The thorium fuel cycle is more protected against proliferation, but is also much more expensive than the uranium-plutonium cycle in a typical reactor setup. Liquid-fueled molten salt reactor designs, however, bypass the prohibitive expense of U-233 refabrication by avoiding the stage entirely, keeping the chain reaction running with nothing but thorium input required. MSRs can use any fissile material as fuel, and are relatively safe to operate, due to passive features inherent to the design.
ContributorsGalbiati, Joseph Nicco (Author) / Martin, Thomas (Thesis director) / Foy, Joseph (Committee member) / Barrett, The Honors College (Contributor) / School of Sustainability (Contributor)
Created2014-05