2025 MU Dissertations - Freely available online
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Item Human-centered design, disability, and accessible research experiences : a multiple method study, co-design framework, and model for inclusive instrument design(University of Missouri--Columbia, 2025) Miller, Alissa; Adkins, Denice[EMBARGOED UNTIL 05/01/2027] Research studies and information design lifecycles often include surveys, interviews, and user testing as part of the process-oriented approach to sharing research outcomes with the world. However, there is a lack of research regarding inclusive instrument design, which would help remove barriers experienced by people with and without a disability when taking surveys or participating in interviews or usability testing required for a research study. Using human-centered design, human-computer interaction, and disability studies perspectives, web-based instruments can become more inclusive and accessible. This sequentially phased 4-article dissertation presents lessons learned of inclusive instrument design as a solution-based framework that enables access to knowledge and helps create a positive research study experience for the broadest representation of humans possible. Everyone is impacted by a disability, impairment, or limitation at some point in their life, whether visible, invisible, permanent, temporary, or situational. Therefore, starting the design of instruments used in research studies with a human-centered and inclusive design mindset can increase the chances of creating more usable surveys and interview protocols. The research approach includes people with disabilities and disability advocates as part of the research process and uses multiple methods of co-design sessions, surveys, interviews, observation, document analysis, and automated and manual accessibility evaluation (including user and expert testing). This approach is a form of universal, participatory, and co-design, with researchers and stakeholders working together on various aspects of the research and design process. In addition to uncovering challenges and design flaws of web design, existing survey tools, or instrument question formats in an exploratory manner (Study 1), critical review of the literature (Study 2), and domain analysis and survey accessibility conformance evaluation (Study 3), this research will also identify user challenges with instruments and instrument preferences from surveys and interviews used in a co-design multiple methods study (Study 4). The themes, findings, and criticality counts across the four studies helped to inform my interpretation of the dissertation research, yielding eight conceptualizations which are used to address the research questions. This knowledge informed my model for inclusive instrument design practices, adding procedures, precedent, and new knowledge to the literature on disability and HCI research. This enriched understanding will assist researchers and designers in utilizing an inclusive instrument for conducting research studies that use online surveys and conduct interviews or test web-based products. Additionally, improving such web-based experiences for people with a disability, impairment, or chronic condition may lead to better experiences for everyone. Resulting recommendations include (1) an alternative to traditional medical-based demographic questions used in data collection for the ability status, (2) co-design as a research method, and (3) a model for inclusive instrument design. The inclusive instrument design recommendations can be adapted to future instrument designs, including procedures for multiple method survey accessibility evaluation and instrument design tenets by criticality. Ultimately, this qualitative study uses multiple methods to learn, create, test, and evaluate an inclusive instrument design model that enables a more inclusive research study experience for everyone.Item Regression analysis of semi-competing risk data and precision medicine(University of Missouri--Columbia, 2025) Zheng, Tiange; Sun, Jianguo[EMBARGOED UNTIL 05/01/2026] Right-censored failure time data commonly occur in various fields, including economics, medical studies and public health, and a great deal of literature on their analyses has been established. However, there still exist some problems related to their analyses that have not been investigated. In this dissertation, we will discuss three such topics and provide some statistical methods. The first part of this dissertation focuses on semi-competing risk data problem, which is often encountered in clinical studies when there are related endpoints. The data structure consists of a terminal event and a non-terminal event, where the terminal event may censor the non-terminal event, but not vice versa. Such relationship between the two events brings difficulty to estimation procedure and has been well studied in the past twenty years. However, most of the existing methods, either the copula models or the illness-death models, require the specification of the underlying correlation between the non-terminal event and terminal event. In Chapter 2, we propose an alternative conditional approach, which is more attractive and natural if the non-terminal event is of main interest. In the proposed method, a class of flexible additive and multiplicative models and the additive hazards model are employed to model the non-terminal and terminal events, respectively. For inference, an estimating equation-based procedure is developed and the asymptotic properties of the resulting estimators are established. In addition, a model checking procedure is provided. The numerical results indicate that the proposed methodology works well in practical situations and it is applied to a real set of data that motivated this study. The second and third part of this dissertation focus on precision medicine. There are two types of heterogeneity considered in this dissertation: the same treatment can have different effect for different patients in a clinical study, or the effect can be heterogeneous on the same patient across different quantiles of the survival time. The first type heterogeneity is referred to as the subgroup analysis, and the second type is referred to as the quantile regression. There has been a great deal of literature for subgroup analysis methods for censored data and quantile regression for censored data, but there has been no method considering the case when both of the heterogeneity exists. In Chapter 3, to address such double heterogeneity, we propose a pairwise fusion penalty approach that can identify the subgroup structure and estimate the covariate effects simultaneously. It is in the similar spirit of regularized variable selection, but the penalized term is the pairwise difference between the coefficients of subjects. For the implementation of the proposed method, an alternating direction method of multipliers algorithm is developed and the asymptotic properties of the resulting estimators are established. To assess its empirical performance of the proposed methodology, a simulation study is performed and indicates that it works well in practical situation. Finally, it is applied to the well-known Stanford heart transplant data and suggests the possible existence of a threshold with respect to the diagnostic effect of the T5 mismatch score. In Chapter 4, we focus on censored quantile regression (CQR) and propose a prediction method for CQR with high-dimensional covariates. Instead of variable selection, we adopt the model averaging framework since we are more interested in prediction. Unlike with variable selection method, model averaging method do not select the best model, but assign different weights to a group of candidate models, so that the prediction accuracy is increased, especially when the noise level is high and impacts the model selection. We use the jackknife criterion to search the optimal weights for each submodels. To evaluate the prediction performance of the proposed method, we conduct a simulation study and apply it to a real data example, and compare the prediction error with other variable selection methods established for high-dimensional CQR.Item The role of board of directors in M&A and disclosure practices : international evidence(University of Missouri--Columbia, 2025) Yun, Byongwook; Khurana, Inder[EMBARGOED UNTIL 05/01/2026] Using staggered country-level shocks to enforcement of board neutrality rules, this study examines the effect of board neutrality rules on mergers and acquisitions outcomes (M&A) and managers' voluntary disclosure strategies. Board neutrality rules restrict the ability of the board of directors in a target company from implementing defensive measures against a takeover bid. The findings suggest that, in the aftermath of such legal changes, target companies experience more favorable M&A outcomes, including more bids from acquirers and higher chance of M&A completion. Furthermore, managers of target companies tend to increase their issuance of earnings forecasts in response to the enforcement of board neutrality rules, suggesting a strategic maneuver to mitigate the heightened takeover activity. Collectively, the results underscore how regulatory changes concerning these boards can significantly influence M&A outcomes and managers' voluntary disclosure practices.Item In solidarity with communities : how movement journalism is shifting paradigms through cross-field collaboration with activists and civil society organizations(University of Missouri--Columbia, 2025) Zhang, Tianting; Volz, Yong[EMBARGOED UNTIL 05/01/2026] Major social movements in recent years have raised new questions about how journalists should position themselves during times of social injustice to regain public trust and remedy harm perpetuated by extractive journalistic practices. This dissertation examines collaborations between journalism and movement organizations on social justice issues, including reproductive justice, transgender politics, racial justice, and workers' rights. Using a case-study approach, it included 15 in-depth interviews with reporters, editors, and newsroom leaders from three movement journalism organizations, alongside an analysis of 85 secondary documents. The findings showed that the construction of movement journalism centers on movement solidarity, amplifying narratives and lived experiences of marginalized communities. The interview data revealed that movement journalists' multiple dimensions of identities shaped their professional values and practices. Digital ethnography showed that the news organization used digital platforms to foster collective discourse and shared identities, amplifying affective solidarity. As movement journalism pushes for mainstream journalism to reconsider the professional constructions of newsworthiness and professional roles, it brings a paradigm shift to the journalistic norm of objectivity. The study provides theoretical insights into understanding movement journalism from an organizational-level analysis. The study also adds to the scholarship on field theory, showing the nuanced negotiations between movement journalism as an emerging actor and established mainstream journalism. It provides practical implications for journalists, news organizations who practice movement journalism, and the broader journalism field.Item Development of small molecule fluorescent probes for application in neuroscience(University of Missouri--Columbia, 2025) Yadav, Peeyush; Glass, Timothy E.[EMBARGOED UNTIL 05/01/2026] Herein, we develop a series of selective fluorescent sensors based on coumarin and quinolone core designed to image neurotransmitters catecholamines, glutamate and to distinguish between D-/L-amino acids. Included are the main design strategy, synthesis, spectroscopic data (UV/Vis and fluorescence) and their applications in cells and tissue. NeuroSensor 570 (NS570) was designed and synthesized as a cell impermeable sensor with two binding sites to be able to distinguish between glutamate and GABA. Formation of both an iminium ion and a boronate ester gave high affinity upon binding NS570 to glutamate. Because the sensor is charged, one of the possible applications of the sensor is to be able to study vesicle recycling. While the slower binding kinetics of the sensor with glutamate makes it unsuitable to study fast vesicle recycling, its applicability in labeling hippocampal neurons was reported. A series of pH-dependent sensors was developed to label catecholamines and to report their exocytosis. ES525 was developed using FITC as the base fluorophore. The probe gave good fluorescence enhancement upon pH change from acidic to basic, however it failed to give good labeling of chromaffin cells. ES450, based on a coumarin fluorophore, gave greater fluorescence enhancement and a better binding with catecholamines. The labeling of chromaffin cells by ES450 was inconsistent and could not be used further. Finally, (S)-39 and (R)-39 were developed to distinguish between D-/L-amino acids. Because of only one binding site the probes exhibited only a slight difference in fluorescence between the enantiomers. The development of probe with two binding sites will provide a better fluorescence difference as only one of the enantiomers will be able to bind to the secondary site.