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How Loneliness and Misinformation Become Dual Epidemics in the Digital Age
No full textLoneliness and misinformation have both been recognized as critical public health concerns, often described as an epidemic and an infodemic, respectively, due to their widespread impact on large populations. However, little is known about how these two issues may be connected. This dissertation addresses this gap by adopting a novel perspective that explores the relationship between loneliness and misinformation through social identity. Drawing on social identity theory and motivated reasoning theory, Study 1 employs a quasi-experimental design to examine the existence of this relationship and how are they associated. Building on these findings, Study 2 extends the investigation by exploring how loneliness may intensify individuals’ perceptions to specific types of content in social media environments, focusing on the role of the repost function and identity language. Together, this dissertation offers valuable insights for both public health and communication research by highlighting the impact of loneliness on group identification and individuals’ responsiveness to language and social cues within digital media environments.</p
Reasons for Asking: Beyond Journey's End
No full textAs rational agents, we hold ourselves to the standard that reasons justify our beliefs and actions. In a similar vein, the act of asking—how we open inquiry—is also justified by reasons. This dissertation presents a systematic approach to understanding how the different components of inquiry function as reasons for asking. By doing so, it aims to clarify key concepts within the philosophy of inquiry, focusing particularly on the role of inquiring attitudes and questions in shaping the nature and direction of inquiry.The central argument is that reasons for asking are bi-faceted, consisting of both the inquiring attitude and the question, which together drive the inquiry process. Drawing an analogy from Frege’s distinction between content and force, this dissertation proposes that while these facets may be metaphysically distinct, as they operate in unison within inquiry, they offer a comprehensive understanding of what it means to rationally inquire.</p
A Deep Neural Network Based Variational Bayesian Approach to Sensor-Driven System Monitoring and Control
No full textModern industrial systems (e.g., aerospace, manufacturing, energy) increasingly rely on condition-monitoring sensor data to detect early signs of failure and optimize maintenance. Traditional models struggle with the high-dimensional, non-linear, and time-dependent nature of such data, limiting predictive accuracy. Prognostic Health Management (PHM) leverages sensor data to assess system health and predict failures, but modeling degradation in run-to-failure scenarios remains challenging due to evolving conditions and complex dependencies.This dissertation introduces a deep state-space modeling (DSSM) framework that integrates deep learning, variational inference, and recurrent neural networks (RNNs) to model latent system dynamics. Combining RNNs with variational autoencoders (VAEs), the framework captures long-term temporal dependencies and performs robust probabilistic inference. A hybrid latent state structure—continuous and discrete—allows it to represent diverse degradation behaviors, from gradual wear to sudden faults, enhancing interpretability and robustness.Extensive evaluation on simulated and real-world datasets, including a wind turbine case study, demonstrates the model’s ability to track latent degradation and accurately estimate remaining life (RL) or time of event (TE). To adapt to dynamic environments, the framework also integrates active learning for selective model fine-tuning, reducing the need for retraining with new data. This approach advances predictive maintenance and reliability assessment in complex, sensor-driven systems.</p
Breast and Gynecological Cancer in Diverse Populations: From Clinical Outcomes to Pathogenesis
No full textWomen of African ancestry diagnosed with breast, endometrial and ovarian cancer experience the worst survival outcomes. The Caribbean region has one of the highest breast cancers (BC) mortality rates. In the Caribbean, BC is prevalent among premenopausal women and is commonly diagnosed at a younger age. Similarly, endometrial cancer (EC) incidence is increasing, whereas ovarian cancer is the most lethal gynecologic cancer. Increasing African ancestry has been associated with a concurrent increase in the odds of both serous and copy number high EC, the most aggressive subtypes. Epithelial ovarian cancer (EOC) accounts for 75% cases, with high-grade serous carcinoma (HGSC) being the most common subtype. In HGSC, hormonal therapy is commonly used as a treatment option in patients with recurrent HGSC who have exhausted or are not suitable for further standard lines of systemic chemotherapy. Immunohistochemical profiles have demonstrated differential expression of ERα and PR in HGSC and correlation with survival outcomes. Preliminary data indicate that in a cohort of HGCS, 79% expressed ER of which 51% were ER+/PR-. ER+/PR- patients have worse overall survival compared to ER+/PR+ patients (overall survival Log-Rank p=0.031). Tumors in the TCGA genomically assigned to African Americans with breast, head and neck, and endometrial cancers exhibited a higher level of chromosomal instability and the frequencies of TP53 mutations and CCNE1 amplification were also increased. These features are independently linked to worse survival in ovarian cancer. Women of African ancestry are at higher risk of BC, EC and HGSC because of distinct pathways and exposures driving aggressive disease: in BC, we have found that based on nativity, Black US born women, who have higher African ancestry, are experiencing worse survival outcomes. In EC, we found that increasing African ancestry increases the odds of being diagnosed with aggressive EC. In HGSC, we have found that lower progesterone receptor expression confers worse survival outcomes.</p
Proton Exchange Membrane Fuel Cell's Degradation Under Voltage Reversal and Innovation for Electrochemical Lithium Extraction
No full textProton exchange membrane fuel cells are likely to encounter voltage reversal under hydrogen starvation conditions during real-life operations.However, it is still not fully resolved which side experiences faster or more severe degradation. Different operating conditions can further complicate this issue. In this study, we investigate the degradations on the anode and cathode sides separately after voltage reversal under different humidity conditions. The experimental results show that the anode side experiences faster and more severe degradations, but the cathode side has more pronounced effects on cell performances due to the sluggish nature of oxygen reduction reaction (ORR). Our experimental results also show measuring oxygen transport resistance can be a diagnostic tool to monitor the degree of fuel cell degradation before observable significant cell performance declines.Fabrication of thick (900-1500 µm), crack-free lithium manganese oxide (LMO) electrodes was reproducible by using an innovated slurry casting method. The selectivity and intercalation capacity of the thick electrodes were evaluated in chloride solutions with main cations in brines and in synthetic Salar de Atacama brine using cyclic voltammetry (CV) measurements. Analyses of the CV data indicated an excellent Li+ selectivity of Li+/Na+=152.7 was achievable under voltage-controlled conditions. The mass specific intercalation capacity of the thick electrodes was 6.2-11.3 mg per gram of LMO whereas an area specific capacity of 0.282 mg/cm2 was achieved with the thickest electrode, which was 3-11 folds of that for the thin electrodes reported in literature. In addition, 82% of capacity was retained over 30 intercalation/deintercalation cycles. XRD measurements revealed that both Faradaic diffusion-controlled or battery-like intercalation and pseudocapacitive reaction contributed to the selectivity. This work establishes practical technology for thick electrode fabrication that promises reduction of the manufacturing and operational cost. </p
Understanding and Extending the N-Degron
No full textProteostasis – the balance of protein synthesis, folding, and degradation – integrates with stress signaling, metabolism, and cell death. Central to this network is the Arg/N-degron pathway and its defining enzyme, arginyltransferase 1 (ATE1). This dissertation explores ATE1 and the N-degron pathway as both evolutionarily conserved, mechanistic regulators in eukaryotic biology and as possible translational tools.First, I show that ATE1 regulates HIF1α stability in a hydroxylation-dependent manner, contributing to our lab’s work in establishing arginylation as a parallel axis to canonical VHL-mediated hypoxia sensing. Second, I identify a redox-sensitive [Fe-S] cluster in ATE1 that is required for its activity and demonstrate that both [Fe-S] cluster and heme biosynthetic pathways are necessary for ATE1-induced cell death in yeast. Third, I reveal that this cell death occurs independently of ATE1’s canonical role in ubiquitin-mediated degradation, instead pointing to a mitochondria-dependent mechanism that may involve ATP synthase subunit c and the mitochondria permeability transition pore. Finally, I extend N-degron logic into applied contexts, developing proof-of-principle strategies for targeted protein degradation: a type II N-degron PROTAC and a cleavage-resistant ubiquitin fusion, each capable of reducing levels of the oncogenic protein MCL1 in preliminary studies.Together, these findings elaborate on the N-degron pathway, and more specifically ATE1, as a redox-sensitive mediator situated at the intersection of proteostasis, mitochondrial biology, and cell fate, while also demonstrating how its underlying principles can inspire next-generation protein degradation technologies
Conceptualizing and Exploring ESG (Environmental, Social, Governance) in Internal Public Relations: An Employee-Centered Perspective
No full textThis dissertation explores ESG (Environmental, Social, and Governance) from the perspective of internal public relations, aiming to understand employee perceptions of ESG and its communication through two consecutive studies. Both studies employed quantitative surveys conducted with U.S. employees.Study 1 examined how employee perceptions of ESG can be structured by conceptualizing and operationalizing it through a reliable, measurable quantitative scale. Grounded in stakeholder theory, the study introduced a scale of 24 items that address the elements underlying the ESG construct. This scale specifically focused on employee perceptions of corporate ESG efforts from both external (i.e., initiatives targeting the public or broader management strategies) and internal (i.e., initiatives directly affecting employees’ experiences within the company) perspectives of environmental (E), social (S), and governance (G).Study 2 built upon Study 1, examining the role of communication in shaping employee perceptions of ESG and, in turn, fostering positive relationships with their companies. Adopting media richness theory and relationship management theory, Study 2 highlighted the importance of rich-feature mediums in enhancing the communication quality of ESG content and format, as compared to lean-feature mediums, which had a negative impact on both aspects. The results showed that high-quality ESG content significantly affects employee perceptions of ESG, thereby strengthening the employee-organization relationship (EOR) in terms of trust, control mutuality, satisfaction, and commitment. In contrast, communication quality in terms of format did not show a significant relationship with employee perceptions of ESG, nor did it contribute to a positive EOR.This dissertation makes significant theoretical contributions by expanding the scope of ESG studies to the public relations framework. It also provides practical guidelines for companies to enhance ESG initiatives and strengthen internal relationships through strategic ESG communication and management.</p
LanModulin as a Biomarker-Targeting Platform for Precision Imaging
No full textBiomarkers play a critical role in modern medicine, guiding disease detection, monitoring, and treatment decisions. Protein biomarkers offer dynamic insights into physiological and pathological processes, making them invaluable tools for diagnostic imaging. This dissertation explores the development of a novel biomarker-targeting platform by integrating LanModulin (LanM), a high-affinity lanthanide-binding protein, with a HER2-specific Designed Ankyrin Repeat Protein (DARPin). By leveraging the molecular specificity of HER2-targeting DARPins and the unique lanthanide-binding properties of LanM, this work aims to enhance the stability and precision of imaging agents for HER2+ breast cancer. Through the design, expression, and characterization of this fusion protein, this research establishes a framework for the use of LanM as a lanthanide carrier in bioimaging, highlighting its potential to advance biomedical applications that rely on lanthanide-based diagnostics and imaging techniques.</p
WeMigration: Remapping Women´s Voices in Contemporary Brazilian Writing
No full text In this dissertation I explore the voice of the nordestina through the literary and cultural analysis of three different migration stories told by Marilene Felinto´s The Women of Tijucopapo (1982), Clarice Lispector´s The Hour of the Star (1977), and Helena Parente Cunha´s Woman Between Mirrors (1984). The cultural and historical context in which they are writing correspond to the opening to democracy (abertura) phase within the military coup from 1964-1984 in Brazil. Through their stories, these women writers respond to different contexts of marginalization and silencing that are products of an ideal of nation commonly propagated by authoritarian regimes. “WeMigration” conceptualizes the framework that guides my analysis, inspired by Marilene Felinto´s story of reverse migration. Therefore, remapping means to question and challenge official discourses and representations that has a history of erasure of women´s voices and racialization. Through the exploration of the transformative element of displacement in these different types of migration, I discuss the intersection of gender, race, social class and geography. Chapter 1 comprises mythical reverse migration as claiming of an identity and a manifesto of the nordestina voice against racism and misogyny in Brazil. Chapter 2 explores the resistance of the nordestina through geographical and metaphysical displacement to debunk racialization myths of Northeast Brazil and the nordestina identity. Chapter 3 explores psychological migration through the self-reflections of the female protagonist in the mirror while raising questions on colonial and patriarchal context in Salvador, Bahia, Brazil. My critical analysis focuses on the writers´ poetics and ethics to amplify marginalized voices from the Northeast by transforming the female objectified body into the subject of enunciation. </p
Strategic Talent Hiring and Its Implications
No full textThis dissertation examines firms’ strategic talent hiring and its implications through three empirical essays. Findings from the first essay indicate that target firms strategically increase their job postings before acquisition announcements as an impression management tool to signal their growth prospects to acquiring firms. This tactic can enhance the perceived value of target firms by acquiring firms, thereby increasing the acquisition premiums that target firms receive. Findings from the second essay suggest that awareness of ongoing acquisitions encourages acquirers’ rivals to strategically post jobs near the target firms as a competitive tool. This approach can effectively poach talent from target firms, potentially disrupting acquisition success. Findings from the third essay show that executives’ long-term environmental and social (E&S) incentives motivate them to hire employees with E&S human capital, while short-term E&S incentives encourage them to acquire target firms with E&S performance that is superior to that of their own firms. E&S hiring inspired by long-term E&S incentives can reduce firms’ E&S reputation risk over the long run. This dissertation contributes to the strategic human capital literature by uncovering novel factors that drive firms to strategically hire talent and examining the implications of these hiring activities.</p