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Recent Submissions

Female Representation Matters: The Identification of Young Women with the Embodied Ecological Ethē of Public Female Role Models
(2023-05) Broccard, Delphine
This research project sought to find out if college-aged women have public female role models (PFRM) and how the former group identified with the latter. Over the last two hundred years, women and men in the U.S. have worked to improve the current standing of women in society. Today, women continue to gain influential power, making a difference in the world, despite the institutional and inter/personal oppressions that still exist. The examination of the words and/or actions of public female figures in a patriarchal society called for the reconceptualization of ethos, traditionally understood as “ethical,” referring to a “rhetor’s character” (Crowley & Hawhee, 2004, p. 20). While Aristotelian ethos was conceived according to the agency of the dominant social group, embodied ecological ethē accounts for the rhetor’s physical body (embodiment) and its location (ecology). In this manner, ethos is pluralized—ethē—and affirms women’s diverse realities based on their identities and their environments. Specifically, this study focused on how public female role models construct their ethē through interruption, advocacy and relation. The first step for revealing how young women identify with these involved determining if they had public female role models. Survey results indicated that the majority of college-aged women have a PFRM, one who likely matches at least one of their racial/ethnic maker(s). Building on these findings, young women spoke about their reasons for admiring their respective PFRM in focus groups. The feminist rhetorical analysis of the focus groups’ transcripts revealed that out of the three types of embodied ecological ethē—interruption, advocacy and relation—female students identified with the first two. What is more, a young woman’s identification with her PFRM’s embodied ecological ethē proved meaningful. Through identification, a college-aged woman enhances her daily life by adopting the ethē of her PFRM.
Don't Remember!
(2023) Balighi, Ali (TTU)
Don’t Remember is a musical exploration that delves into the depths of negative self-dialogue and the complexities of detaching oneself from it. Inspired by the philosophies of Nietzsche and contemporary psychological insights, this composition challenges the pervasive patterns of self-criticism and intrusive thoughts that plague the human mind.
Host-associated Metal Stressors Alter Microbial Community Structure and Function
(2023-05) Islam, Shariful
Metal nutrients are crucial to many vital biological processes, which is why they are required for the survival of all living organisms. The most extensively used redox active metal is iron (Fe). At the host-pathogen interface, these metals play a key role in determining the outcome of an infection. Pseudomonas aeruginosa and Staphylococcus aureus, two clinically significant bacteria, are common and opportunistic infections in human hosts. S. aureus can modify its physiology in a variety of ways to adapt to the challenging conditions of the host environment. The fermenting small colony variants (SCV) phenotype is one of the adaptations, which is well documented to be innately tolerable to specific kinds of antibiotics and heme toxicity. In our studies, S. aureus were treated with an iron chelator, 2,2’ dipyridyl, in order to provide them with selective pressure created by the chelator. The study indicates that the suppression of respiration and the development of the SCV phenotype in S. aureus are two key effects of iron deprivation. Furthermore, compared to the naturally occurring subpopulation of SCVs within an S. aureus community, prolonged growth in iron starvation encourages enhanced appearance of stable aminoglycoside resistant SCVs. S. aureus were also exposed to different concentrations of transient heme toxicity. The study demonstrates that some, but not all, respiration deficient SCV phenotypes appear to be more resistant to heme toxicity than the host's heme detoxification system against transient exposure to heme. Genes in pathogenic bacteria like P. aeruginosa lose their functionality over time due to prolonged social interactions. It is anticipated that both wild-type and mutant bacteria will co-exist in infection sites, with the mutant potentially benefiting from the wild-type bacterium's resources. By employing the knowledge of the presence of this archetypal shared resource as a control, we sought a method that would enable the generation of new shared resources. This study explores pyoverdine as a potential shared resource in P. aeruginosa by treating the mono and co-culture of cells with a metal chelator, 2, 2’ dipyridyl. P. aeruginosa uses a related collection of virulence factors to infect and produce disease or disease symptoms in both plants and animals, demonstrating that common mechanisms of pathogenesis endure across divergent evolutionary lineages. Because they are genetically tractable, Arabidopsis thaliana plants can be used as experimental models for microbial disease in mammalian hosts. In an effort to identify new P. aeruginosa virulence factors, this study also has developed an alternative plant infection model in laboratory based liquid conditions without the need for an expensive plant growth chamber.
Perceptions of Teachers from a Developing and a Developed Country on Global Collaboration and Environmental Sustainability Before and After Engaging in Their First Global Collaboration
(2023-05) Klammer, Elizabeth M.
This participatory action research study explored two fourth-grade private school elementary science teachers’ perceptions of their initial global collaboration using a project-based learning activity on environmental sustainability. Participants were from Honduras, considered a developing country, and from the United States of America, a developed country. Semi-structured 30-minute interviews, a modified Hett’s Global Mindedness Scale, onsite observations, an exit survey, and the use of social media were used to understand the opinions on global collaboration and environmental sustainability. Teachers in both schools explained to their students the purpose of the global collaboration and prepared to do a parallel project on environmental sustainability using an acid rain simulation with radish seeds. Analyzed through the theoretical framework of situated learning and a conceptual framework of the global continuum, this study defines the social contexts of politics, economics, and culture seen throughout the facilitation of the study's global collaboration. The teachers reported a positive collaboration, an increase in cultural awareness, and a negative experience due to lack of communication between teachers. This study revealed the opportunities and challenges for novice global collaborators in developing self-directed skills in communication between partners from different countries. Further research is needed to compare public and private elementary school global collaborations between developing and developed nations.
Sex Chromosome Evolution in Willows (Salix spp.)
(2023-05) Hu, Nan
The evolution of sex chromosomes is a fascinating subject in evolutionary biology, particularly in the angiosperm family Salicaceae. Although all species in this family are dioecious, meaning they have separate male and female individuals, they display a remarkable diversity of sex chromosomes, with the sex-determining region located on different chromosomes. In my dissertation, I employed various techniques, including ecology, population genetics, genomics, and phylogenetics, to study the evolution of sex chromosomes in willows (Salix spp.), a genus within Salicaceae. The second chapter of my dissertation aimed to investigate the sexual dimorphism of Salix exigua and Salix nigra. Sexually dimorphic traits have not commonly been documented in willows, but their presence is important because they may influence the movement of sex chromosomes. I measured early spring bud density, catkin number, and flower number per catkin in S. exigua, as well as flower number and catkin number per flower in S. nigra, across four sampling periods. The results indicated that there was no sexual dimorphism in pre-season buds per branch in S. exigua, but males produced more flowers per catkin and more catkins per branch than females in both S. exigua and S. nigra. The presence of reproductive sexual dimorphisms in Salix species provides evidence that sexual selection has the potential to play a role in the evolution of their mating strategies and sex determination system. The third chapter of my dissertation aimed to identify the ancestor of the sex chromosome in the Salix clade. The phylogenetic tree of Salix is ambiguous as to whether the ancestral sex chromosome is chromosome 7 (Chr7) or chromosome 15 (Chr15). Identifying the ancestral state of the sex chromosome is crucial for understanding the evolutionary events during sex chromosome and sex determination evolution. I conducted a comparative genomic analysis and found that patterns of homology on Chr7 and Chr15 across Populus mexicana (the outgroup), S. nigra, and S. exigua indicated that the sex determination locus likely originated on Chr7. Using these results, I was able to reconstruct changes in the gene content and genes controlling sex determination that occurred during the early evolution of willows. In the fourth chapter, I conducted a detailed study in Salix examining the shift from an XY to a ZW sex determination system that occurred in the same location (homologous transition) on chromosome 15 during Salix evolution. First, I discovered that the sex-determination system for S. exigua is on Chr15 and it has XY heterogamety. Based on the phylogeny of Salix and other known sex chromosomes in the genus, I determined that there was an ancient shift from an XY to a ZW sex determination system on chromosome 15. I conducted a detailed comparison of the S. exigua X and Y chromosomes with the S. purpurea Z and W chromosomes to reconstruct the events that resulted in the shift. By utilizing chromosome-level assemblies, half-sib families, and population samples from the wild, I traced the loss of the X chromosome and the transformation of the Y into both the Z and W during this transition. The results suggest that the origins of sex chromosomes during homologous transitions may be more flexible than previously considered. Specifically, both the W and Z chromosomes have arisen from the Y chromosome in willows, which is unexpected since the W chromosome is more likely to arise from the X chromosome due to the feminizing genes they both carry. These findings indicate that the mechanism of sex determination and the unexpectedly low genetic load on the Y chromosome have contributed to the flexibility in the origins of sex chromosomes during homologous transitions. These findings shed new light on the dynamics of sex chromosome evolution in plants and have implications for the understanding of the evolutionary biology of sex determination systems.