Electronic Thesis or Dissertation

Suaeda linearis is an edible halophyte crop with nutraceutical properties that is native to Florida. This study investigated how the biomass production and mineral content of aquacultured S. linearis was affected by harvest frequency during a 10-week period using four different harvest treatments. Under the first treatment (T1) plants received zero intermittent harvests, the second (T2) received harvests every five weeks, the third (T3) received harvests every 3.3 weeks, and the fourth (T4) received harvests every 2.5 weeks. The results indicate that biomass production and mineral content were both strongly affected by harvest treatment. Intermittent harvesting decreased biomass production and conversely, intermittent harvesting increased the quantities of certain desirable minerals in S. linearis. Early harvests of the study plants were small, suggesting that 13-15 weeks after germination is the earliest time a harvestable yield can be achieved from S. linearis.

This research studied the effects of mooring line pretension, spring safe working load, and spring response curve on peak loads and platform surge. The maximum tension load from the optimized assembly was applied to a modelled section of 8-strand multiplait rope to study stress concentrations. The analyses yielded a mooring line pretensioned at 1250 kN with a 4500 kN safe working load degressive spring was optimal. Fatigue damage from 12-hour duration of 50-year storm conditions was 8.04 × 10−6. Infinite life is predicted at annual average conditions. The peak tension from 50-year storm conditions of 3671 kN and annual average conditions of 1388 kN was applied to the section model, yielding a maximum stress of 3.70 × 108 Pa and 2.01 × 108 Pa, respectively, from friction and longitudinal compression of the rope’s cross section. The maximum stress from the static structural analysis was 33.5% of polyester’s ultimate strength, based on the maximum stress failure criterion.

In the last twenty years, cultural resource preservation and management is becoming an impactful venture for all levels of a community in the build-up and wake of a disaster. All forms of government, from local to international, are seeing the value of cultural resources to the resiliency of an area and yet there is more growth to be seen in disaster management planning. With Hurricane Nicole sweeping the coast of Palm Beach County in November 2022, the reality of having a pre-storm assessment of cultural resources became paramount as the state of Palm Beach County’s cultural resources management plan is ill-equipped to handle the growing rise of climate change. This thesis utilizes the National Park Service’s Cultural Resource Climate Change Strategy (CRCC Strategy) as a foundation for developing a cultural resource management document for unincorporated areas in Palm Beach County. From the CRCC Strategy, interview questions were developed and delivered to Palm Beach County Officials to help with the development of the Cultural Resource Document. With climate change and resilience as the backbone of this thesis, the Adaptive Cycle of Resilience Theory is integrated into the development and analysis of the Cultural Resource Document. To bring practicality to the Cultural Resource Document, Dubois Historic District Park is used as its case study. The outlook on the creation of the Cultural Resource Document is to provide a steppingstone for unincorporated areas of Palm Beach County to manage cultural resources and provide municipalities an entry into disaster management studies.

Coral reefs around the globe have undergone widespread degradation due to a myriad of natural and anthropogenic stressors. Climate warming, in particular, has emerged as an especially pressing threat, reshaping not only the biodiversity of coral-reef ecosystems worldwide, but also undermining the vital ecosystem services they provide. Yet amidst this decline, there is growing evidence that many coral species are expanding their ranges poleward into historically cooler subtropical and temperate marine environments thereby establishing critical refugia in response to climate warming. However, understanding the long-term viability and potential of these emerging refugia under ongoing climate change remains an area of active research, constrained by the temporal limitations of modern ecological studies. In addressing these challenges, this dissertation explores insights from a newly discovered late Holocene record of coral community development off southeast Florida, shedding light on historical coral range expansions, and providing critical context for assessing the future response of reef-building coral communities to continued climate warming. Using a combination of high-precision uranium-thorium dating and detailed paleoecological analysis of well-preserved subfossil coral skeletons, we provide new evidence that diverse coral communities dominated by Acropora spp. expanded to the nearshore hardbottom habitats off northern Broward County during a period of warming in the subtropical western Atlantic between 3500 and 1800 years before present. However, despite this historical precedent of range expansion in response to regional warming, modern comparisons reveal a significant shift towards low diversity coral assemblages dominated by stress-tolerant coral taxa, suggesting that ongoing range expansions may be constrained by new challenges that were absent during the late Holocene. These findings underscore the need for comprehensive conservation strategies informed by historical baselines to navigate the complex dynamics of coral reefs in the face of climate change.

This qualitative study furthers understanding of psychological contract violation experiences as examined through the lens of administrative middle managers in higher education settings. Psychological contract is defined as unstated expectations in the employment relationship which, when violated, results in negative outcomes for employers and employees. In higher education, middle managers are professional staff with titles such as director, associate director, or assistant director across academic and student affairs units. The purpose of this phenomenological study was to explore the meaning of violation experiences for administrative middle managers in higher education settings. This study advanced understanding of post-violation outcomes on participants’ work and future career intentions. This study found that participants’ psychological contract violation experiences had a wounding effect, including negative emotional impacts, feelings of isolation, increased vulnerability, and feelings of responsibility for the violation experience. In addition, participants made sense of their violation experience by focusing on their passion for serving students, the importance of work to their identity, and the responsibility they felt as leaders. Study participants remained in their work settings despite the violation experience and negative impacts. This study resulted in implications for practice for three entities: higher education institutions, administrative middle managers, and professional associations.

Evidence that supplementation with prebiotics, probiotics, or combinations of both (synbiotics) enhances the health, growth, and survival of aquacultured teleosts has sparked significant research into their application. This study evaluates the effects of β-glucan and Pediococcus acidilactici synbiotic supplementation in aquacultured Florida pompano (Trachinotus carolinus).
The first study defined embryonic and larval organogenesis. The gastrointestinal tract is differentiated, but not yet fully functional within the first seven days post hatch evidenced by the absence of gastric glands, gastric mucous cells, lipid vacuoles in the anterior intestines, and the persistence of acidophilic supranuclear vesicles. Synbiotics may serve as a source of exogenous digestive enzymes prior to complete gastrointestinal maturation.
The second study investigated hematological, serum biochemical, and protein electrophoretic changes with and without β-glucan and P. acidilactici symbiotic supplementation. Significant decreases in blood urea nitrogen and carbon dioxide concentrations were observed in supplemented Florida pompano compared to controls and may represent enhanced mucosal tissue health, urea excretion, and osmoregulatory function associated with supplementation.

High nest incubation temperatures can result in numerous physiological and behavioral outcomes in sea turtle hatchlings, including body characteristics for efficient swimming. This project examined the effects of incubation temperature on yolk metabolization, body morphology, buoyancy, swimming kinematics, and blood chemistry to better understand variations in locomotor performance in loggerhead (Caretta caretta) sea turtle hatchlings of South Florida. Nest temperatures, body measurements, and blood samples were collected in conjunction with swim-trial force measurements and video recordings. Data suggest hatchlings from nests with higher incubation temperatures tend to be significantly smaller in size, less buoyant, and display lower power stroke frequencies. These variations between hatchling morphology and performance indicate hatchlings from high temperature nests (i.e., >33°C) may exhibit weaker swimming abilities. The results of this study provide a further understanding of the effect of incubation temperatures on hatchling physiology and early survival in their important frenzy period.

One of the central issues in stability analysis for control systems is how robust a stability property is when external disturbances are presented. This is even more critical when a system is affected by time delay. Systems affected by time delays are ubiquitous in applications. Time delays add more challenges to the task of stability analysis, mainly due to the fact that the state space of a delay system is not a finite-dimensional Euclidean space anymore, but rather an infinite dimensional space of continuous functions defined on the delay interval. In this work, we investigate robust output stability properties for nonlinear systems affected by time delays and external disturbances. Frequently in applications, the requirement of stability properties imposed on the full set of state variables can be too strenuous or even unrealistic. This motivates one to consider robust output stability properties which are related to partial stability analysis in the classic literature.
We start by formulating several notions on integral input-to-output stability and illustrate how these notions are related. We then continue to develop Lyapunov-Krasovskii type of results for such stability properties. As in the other context of Lyapunov stability analysis such as global asymptotic stability and input-to-state stability, a Lyapunov-Krasovskii functional is required to have a decay rate proportional to the magnitudes of the state variables or output variables on the whole delayed interval. This is a difficult feature when trying to construct a Lyapunov-Krasovskii functional. For this issue, we turn our efforts to Lyapunov-Krasovskii functional with a decay rate depending only on the current values of state variables or output variables. Our results lead to a type of Lyapunov-Krasovskii functionals that are more flexible regarding the decay rate, thereby leading to more efficient results for applications.

Learning to effectively execute goal-directed tasks generally requires guidance from knowledgeable experts that can direct the performer’s attention toward important environmental features. However, specifying the optimal attentional strategies is difficult due to the subjective nature of perceptions and the complexity of the underlying neural processes. The current skill acquisition literature emphasizes action-based contingencies through Predictive and Ecological models when examining attentional processes, while Perceptual Control Theory advocates for perceptual-based mechanisms. To evaluate the efficacy of these models, this study implicitly primed one hundred fifteen participants to focus on action-based or perceptual-based aspects during an interceptive task. It was predicted that the perceptual-based priming condition would result in faster learning and greater resilience to environmental disturbances. However, the highly variable results did not show significant differences in learning rate or resilience between the action and perceptual-based conditions. Ultimately, the variability in the findings suggests that a superior performance depends on numerous factors unique to each performer. Consequently, instructional methods cannot rely on a single optimal attentional strategy for gathering environmental information. Instead, the dynamic interplay between the individual and the environment must be considered to foster the skill development of novice performers.

Urinary incontinence (UI) poses a significant challenge for women across different cultures, as their diverse perceptions of UI impact their decision-making and choices, which are influenced by personal beliefs and preferences. Although research on women's experiences with urinary incontinence has shown substantial progress, encompassing various cultural contexts, more studies are still needed to examine cultural factors and employ the framework of transcultural nursing theory. Additionally, limited research has explored the experiences of older women with urinary incontinence in Nepal. This descriptive phenomenological study aims to explore the lived experience of older Nepalese women dealing with urinary incontinence. By applying the theory of culture care diversity and universality and employing the Colaizzi process for phenomenological data analysis, this study seeks to interpret the experiences of older Nepalese women living with urinary incontinence. Data collection involved conducting semi-structured interviews with 16 participants aged between 60 and 80 years. Three themes emerged from the data: (1) Interference with daily living, (2) Modification of lifestyle, and (3) Impact on the whole family. The findings underscored the need for effective treatments and support systems to assist women with urinary incontinence in managing their symptoms.