Electronic Thesis or Dissertation

In Essay 1, I investigate the Equity Duration Hypothesis, which adapts Macaulay’s fixed income analysis to equity securities, finding evidence that dividend payers are less volatile than nonpayers and that dividend yield is negatively associated with volatility for the all-firms sample. Within the payer sample, however, I find unexpected evidence of a positive association when yield includes all dividends but a conflicting negative association when yield includes only quarterly dividends. This ambiguous evidence is corroborated by a one-year portfolio approach, as a previously strengthening negative relationship has transitioned to a strengthening positive one, with results demonstrably trending against the EDH in recent decades. I further find that high-yield stocks that have experienced negative price shocks are highly volatile and strong support for the EDH using firm-level earnings and cash flows as a proxy for dividends, allowing extension of the analysis to nonpaying firms. Unfortunately, I find abundant evidence supporting the assertions of many researchers who suggest that ED is not a unique asset pricing factor, but rather represents a composite of a firm’s characteristics and is redundant with other factors known to be associated with volatility.

This phenomenological study sought to understand the lived experiences of graduate students engaged in STEM-related Academic Service-Learning (AS-L). For the purposes of this study, Academic Service-Learning is a form of experiential learning whereby students complete a service project as a component of a specific course. This study looked at these student AS-L project experiences at the graduate level as a component of STEM-based courses. While the impact of Academic Service-Learning on the undergraduate experience is well documented, there is no research to date on the graduate experience, much less on graduate students in STEM fields. By understanding the lived experiences of graduate students in STEM-based Academic Service-Learning, this study attempts to fill that gap.
The research questions that guided my study were: (1) What types of project-based experiences are graduate students performing in their Academic-Service-Learning designated courses? (2) What are the lived experiences of graduate students who are conducting AS-L projects in the community as a component of a STEM-based AS-L course as perceived by students, faculty, and community partners. (3) What are the lived experiences of the community partners who are hosting the students for their AS-L projects.

Octopus predation and species selection contribute to community structure in benthic habitats, where plastic pollution accumulates. This study investigated how the bioactive plastic additive oleamide alters trophic interactions and behaviors of the common octopus (Octopus vulgaris) and its prey. We quantified activity budgets and trophic interactions for octopuses and multiple prey types (hermit crabs, free-living crabs, bivalves, and gastropods) before and after exposure to oleamide. Our analysis suggested that some taxa (octopuses and hermit crabs) exhibit more active behaviors during oleamide exposure. Free living crabs responded primarily to the threat of octopus predation, while other taxa did not show clear behavioral responses. Exposure to oleamide increased trophic interactions and the probability of mobile prey taxa being observed on the same side of the aquarium as the octopus, thus increasing the opportunity for predation. Our results support previous research showing that plastic leachates can impair decision-making, making prey more susceptible to predation.

Lexical obsolescence is a topic whose study spans centuries, and yet it is not well-understood. Variously termed lexical mortality, lexical death, and lexical loss, among other names, the phenomenon has been described as both a product and a process, but the scholarship on how and why expressions go out of use has, until recently, been sporadic and sparse. The last few years have seen attempts to situate obsolescence among other processes of language change, but these have mostly focused on obsolescing constructions in modern languages. The present study, by contrast, investigates words that went obsolete in Late Middle English, suggesting a methodological approach designed to overcome the challenge of finding that which is no longer there, namely the consultation of a comprehensive online historical dictionary, and proposing an explanatory framework within the tradition of onomasiology and semasiology that positions obsolescence as a diachronic result of the habitual and contextually driven corporate deselection of linguistic constructions.

Previously published in Geographies 2023, 3(1), 161-177 (DOI: https://doi.org/10.3390/geographies3010010)
Inundation dynamics coupled with seasonal information is critical to study the wetland environment. Analyses based on remotely sensed data are the most effective means to monitor and investigate wetland inundation dynamics. For the first time, this study deployed an automated thresholding method to quantify and compare the annual inundation characteristics in dry and wet seasons in the Everglades, using Landsat imagery in Google Earth Engine (GEE). This research presents the long-term time series maps from 2002 to 2021, with a comprehensive spatiotemporal depiction of inundation.
In this paper, we bridged the research gap of space-time analysis for multi-season inundation dynamics, which is urgently needed for the Everglades wetland. Within a GIS-based framework, we integrated statistical models, such as Mann–Kendall and Sen’s Slope tests, to track the evolutionary trend of seasonal inundation dynamics. The spatiotemporal analyses highlight the significant differences in wet and dry seasons through time and space. The stationary or permanent inundation is more likely to be distributed along the coastal regions (Gulf of Mexico and Florida Bay) of the Everglades, presenting a warning regarding their vulnerability to sea level rise.

I examine the importance of corporate scientific research. It is crucial to understand the role of corporate scientific research because such a knowledge could form an appropriate response to the current decline of corporate scientific research amidst the evolving innovation ecosystem featured with growing university research and tech companies’ research. R&D is often treated as a single construct in accounting and finance research for firm innovation. However, corporate scientific research (“R”) has different implications for firm innovations, “R” creates new knowledge, and reduced investment in "R" may lead to a loss of internal research capability, disrupting the speed and quality of innovation. As such, it is necessary and meaningful to examine "R" separately from "R&D."
Historically, corporate scientific research has played an important role in driving breakthrough innovations. Beginning in the 1980s, there has been a decline in corporate scientific research in favor of university research and tech companies’ research. Consequently, this raises a question: if corporate scientific research was important, is it still important? This is a fundamental question because if corporate scientific research is still important, declining or even stagnant corporate scientific research would present an issue of concern for firms and the economy.

The Winston-Lutz has been the standard test for isocenter convergence, however, any adjustments needed – in case the test fails – are time consuming since the source of error is not readily available from the results. Isopoint by the Aktina Medical company has been developed to address this problem via decoupling the mechanical from the radiation isocenter and providing the user with information that was inaccessible before. The focus of this research is to perform optimization of the isocenter by using the Isopoint and to confirm the validity of its results, as well as to find how much time is saved via this new technology. The data for this project was collected on a 2012 Elekta Synergy, a Varian 21ix, and a 2021 Elekta Versa through partnership with GenesisCare. Our findings indicate that the Isopoint will allow for more accurate and speedy adjustments of the LINAC (Linear Accelerator) and will be integral in the future of this
field.

In this qualitative study, learning and engaging in leadership among Latino men college students enrolled at institutions of higher education were examined. The purpose of this narrative study was to explore the stories of how Latino men college students become leaders. Furthermore, this study aimed to understand how Latino men college students engaged in leadership and how they transferred their leadership knowledge between institutions of higher education and their home communities. A narrative design was used to study the stories and experiences (Clandinin, 2006; Connelly & Clandinin, 1990) of eight Latino men college students. Oral histories such as storytelling are a generational avenue within the Latin* community (Bordas, 2001; Delgado, 2002: Marrun, 2020; Rodriguez, 2011). Two semi-structured interviews were used to gather the data from the participants and data was analyzed using two cycles of coding. Lozano’s (2015) Latina/o Leadership Journey was used as the theoretical framework for this study to answer the three research questions focused on how Latino men college students became leaders, engaged in leadership, and transferred their leadership knowledge within their communities.
There are three findings to this study that are focused on how Latino men college students become leaders, Latino men’s leadership engagement, and transferring leadership knowledge in different communities. The three findings had two to three themes that support the findings. Each of the findings address and answer the three research questions. Recommendations for policy, practice, and future research are also addressed to support the lived experiences of Latino men college students in their process to become leaders.

By regulating the abundance of prey populations, predators can directly and indirectly influence food web interactions in ways that influence ecosystem function. Predator functional responses quantify how predator foraging rate changes with prey abundance. Due to the large numbers of individuals needed for these experiments, most studies are conducted on small, abundant taxa. Consequently, we know relatively little about the functional responses of many marine taxa, especially those that are large and highly mobile. We present a novel method for studying predator foraging behaviors by integrating two innovative approaches: passive acoustics to document the occurrence of underwater predation events in concert with a recently developed statistical method that uses the times between predation events to estimate functional response parameters. We demonstrate and expand on the application of these methods by quantifying the shape of the predator functional responses for whitespotted eagle rays (Aetobatus narinari) preying on hard clams (Mercenaria mercenaria).

Intermodal facilities, including port operations, play a significant role in the economic framework of the United States by making substantial contributions to the country's GDP, but face challenges managing increased freight volumes. However, increased transportation time within port facilities leads to higher costs, emissions, and impacts on efficiency and sustainability. This thesis aims to develop a concept of operations (ConOps) for improving the efficiency of heavy truck movement outside ports, with goals of reducing congestion, considering greenhouse gas (GHG) emissions, and addressing issues faced by the truck drivers. The study proposes integrating technological solutions to streamline heavy truck traffic at intermodal port facilities, including scheduled truck arrivals and departures, truck stop and rest areas near ports, real-time traffic information, implementation of dedicated truck lanes, and autonomous truck platooning. The focus is improving communication, efficiency, and safety for trucking companies, operations managers, and truck drivers. Using microsimulation modeling in PTV VISSIM (2023), a traffic impact study is also conducted, focusing on a case study near the Port of Miami. A base scenario is developed to represent current traffic conditions, and additional scenarios are implemented to evaluate different strategies, such as dedicated and exclusive truck lanes, freeway lane restrictions, and autonomous truck platooning. Simulation findings emphasize the positive impact of these strategies on travel times and delays, and forecast scenarios account for increased truck volumes. Dedicated truck lanes and truck platooning demonstrate promising results in reducing congestion and improving overall traffic flow. This research supports decision-making for government officials and logistics service providers in sustainable and efficient intermodal freight planning. The study also suggests opportunities for future extensions, including emerging technologies and tailored solutions for different port locations and contexts.