University of Tennessee Institute of Agriculture
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Methodological and Theoretical Advances in the Social Assessment of Ecosystem Services
Get PDFThis dissertation advances the methodological and theoretical foundations of the social assessment of ecosystem services, a growing research approach that uses survey and interview methods to examine how people perceive, prioritize, and relate to nature’s contributions to human well-being. Responding to long-standing critiques of biophysical and economic assessments—including their limitations in capturing social diversity, cultural meaning, and policy relevance—this dissertation presents three empirical studies that improve how social values are captured and interpreted within ecosystem services research.
The first study offers a methodological contribution by demonstrating how the social assessment of ecosystem services can be used to compare expert and public stakeholder perspectives in the Portneuf River Watershed, Idaho. It introduces a structured framework for analyzing perceptions across four social dimensions: recognition, importance, perceived change over time, and the impacts of land-use on service delivery. The results reveal both alignment and divergence in stakeholder views, providing practical insights for participatory and inclusive environmental management.
The second study turns to theory, introducing a value-based model of preference formation. Using a survey across the contiguous United States, it explores how Schwartz’s theory of basic human values predicts individual preferences for provisioning, regulating, and cultural ecosystem services. The findings show that self-transcendence and openness to change values are strongly associated with higher concern for environmental services, offering theoretical clarity on why people value certain ecosystem services over others.
The third study integrates these methodological and theoretical insights into a local case study of the Tennessee River in East Tennessee. It examines how value orientations predict both ecosystem service preferences and policy solution preferences related to plastic pollution. Results show that individuals who prioritize self-transcendence values are more likely to support collective and regulatory policy solutions, highlighting the practical significance of linking values to policy preferences. Together, these three studies demonstrate that the social assessment of ecosystem services is a transferable, scalable, and policy-relevant approach
Given to This Land: Mapping Settler Colonialism in Kituwah, 1682-1810
Get PDFSeventeenth- and eighteenth-century maps of the Cherokee homelands in the Southern Appalachian Mountains spanning present-day Western North Carolina, Eastern Tennessee, Northwest South Carolina, and Northwestern Georgia documented and facilitated European settler colonialism’s accretion in the region. I argue that from the 1750s until the early nineteenth century, ecological destruction resulting from the invasion of settler populations from British colonies and eventually the U.S., who established plantation-style agriculture, drove changes in the Cherokee’s agricultural practices, social connections, and cultural identity directly tied to an incremental land loss of nearly all of their vital spaces. The deracination of Cherokees from their agriscapes and cultural anchors proved significantly more transformative than more overt forms of European conquest in the Cherokee homelands.
My project helps define settler colonialism by demonstrating it is a collective substantiation of land tenure by individual colonizers entrenching on Indigenous lands. My dissertation uses maps as primary source material to detail the entrenchment of European settler colonialism in the Cherokee homelands during the eighteenth century. Early modern European maps were meant for European audiences, but they were more than European productions. Diverse groups of people contributed to colonial cartography. Indigenous communities provided Euro-American informants with geographic knowledge regarding regional hydrography and topography. European mapmakers repurposed Indigenous geographic knowledge of the land to market land speculators’ claims. Indigenous nomenclature for areas with good fishing waters and rich hunting grounds became Baroque royal fantasies, such as Jamestown and Charleston, to attract European buyers. Maps empowered land brokers and enticed settlers to occupy interior territories permanently. Collectively, these groups’ activities would diminish the land’s viability for Cherokee agrarian practices. Maps demonstrate that Cherokees developed multiple strategies for combating colonial entrenchment. As a series of larger-scale maps of the Keowee frontier region reveal, Cherokee women became a source for preserving Cherokee land tenure amongst the destructive environment of colonial agriculture. Cherokees employed their hand-drawn 1785 [Cherokee Map of their Territory] to assert their territorial sovereignty. However, by the final decades of the eighteenth century, every territorial facet of the Cherokee homelands became an untenable amalgamation. Maps from the early nineteenth century that confidently display solidified state boundaries and neat integration of Cherokee towns into the Euro-American landscape belie the enduring battle within
Graphene Oxide and Mesenchymal Stem Cells for Nerve Tissue Engineering: Approaches in Functional Repair and Regeneration After Neural Injury
No full textNeural injuries cause disruptions to the motor, sensory, and autonomic functions that significantly impact a person’s quality of life. Nerves have a limited ability to regenerate, and there are a lack of available treatments that restore the functional capabilities that are lost. Nerve tissue engineering and regenerative medicine offer a promising area of research for developing novel therapeutics to restore function through repair and regeneration after neural injury. Through five chapters, this dissertation investigates, develops, and evaluates novel therapeutics for functional nerve repair involving the components of graphene oxide (GO) and mesenchymal stem cells (MSCs). GO is a carbon-based nanomaterial whose physicochemical and electrical properties have shown promise influencing cell behavior for functional nerve repair; MSCs are multipotent cells derived from a variety of adult tissue sources which have shown promise as a supportive immunomodulator after injury. The first chapter explores these components, in addition to other biomaterials and cell types, that have been commonly used in nerve tissue engineering. The second chapter takes the components poly (lactic-co-glycolic acid) (PLGA) and GO to develop a novel nerve guidance conduit, seeded with MSCs, as a degradable, therapeutic implant for peripheral nerve injuries. We evaluate the biocompatibility and efficacy of the conduit in a sciatic nerve defect model for 6-months. The third chapter advances the cellular component of our therapeutic implant by developing neurospheres, a foundational 3D environment to be co-cultured with MSCs for enhanced functional repair. The fourth chapter aims to improve our understanding of how GO influences neurogenesis, which impacts the timing of implantation after injury. We also evaluate the material’s feasibility as an implant for penetrating traumatic brain injuries. The fifth chapter takes the PLGA and GO components and alters their chemistry for fabrication using resin-based printing. This allows for the expansion of applications from peripheral to central nervous system injuries. Overall, this dissertation improves our understanding of nerve tissue engineering, advances PLGA and GO as a therapeutic scaffold for peripheral and central nerve injuries, and advances MSCs to 3D multi-cellular spheroids, to improve functional repair and regeneration after neural injury
Dynamics, Neutronics, and the Safeguarding of Molten Salt Reactors from Plutonium Diversion
Get PDFMolten Salt Reactors (MSRs) face unique challenges and requirements for material accountancy and control. Current techniques such as item counting and serial numbers are suited for the current fleet of solid-fueled reactors. However, as the next generation of reactors enter the market, new means of material accountancy and safeguarding will need to be introduced. This research takes a novel approach to assessing the plutonium concentration in the liquid fuel medium found in MSRs. When a reactor is subjected to a periodic reactivity transient, it can have drastically different responses depending on frequency of the transient. This frequency response is sensitive to parameters, such as the delayed neutron fraction, that are highly linked to what isotope is currently fissioning (e.g. U-235, Pu-239, etc.). Therefore, if plutonium is diverted, a characteristic change in neutronic parameters are observable in a reactor frequency response. Using this discrepancy, the frequency response can be very low latency, nondestructive measurement that does not disturb reactor operations. This research examines the frequency response while plutonium is being diverted in fast and thermal spectrum MSRs. In doing so, the paper reveals how key neutronic parameters evolve with burnup and change when plutonium is diverted. The means to predicting the frequency response of an MSR is also detailed. Finally, the frequency response is quantified for both normal burnup conditions as well as when a significant quantity of plutonium has been diverted. The final results show that for a small modular reactor sized thermal MSR, a diversion of plutonium is very noticeable in the frequency response. However, for the large fast spectrum MSRs, there is little to no change in the parameters. Therefore, the frequency response signature is not recommended for large MSRs. All custom tools created to perform this study have been uploaded on a public repository. They can be quickly adapted for evaluation of any liquid fuel reactor design. While this study used these specific tools, the method is not married to any tool (i.e. either burnup code or dynamic model) can be replicated using the steps presented here
Hempseed Hydrolysates Exhibit Antioxidant Activity in Food Model Systems
Get PDFIt has been previously determined that many types of protein hydrolysates exhibit antioxidant activity due to their molecular weight and bioactive components. However, the antioxidant efficacy of hempseed hydrolysates when incorporated into food model systems remains unknown. It is pertinent to inhibit lipid oxidation in food systems to prevent quality deterioration, oxidative rancidity and a decrease in shelf life. The research objective of the first chapter was to determine the antioxidant efficacy of hempseed hydrolysates in an antioxidant screening and a nanoemulsion system. Four methods were performed to examine the antioxidant efficacy of various hempseed hydrolysate products and the most effective hempseed hydrolysates were then selected to incorporate into a nanoemulsion system. AHM10 and AHPI10 exhibited the ability to act as antioxidants through mechanisms such as metal chelation, hydrogen atom donation and single electron transfer. AHM10 and AHPI10 were then incorporated into nanoemulsions systems, and the primary and secondary oxidation products under accelerated oxidation conditions were quantified to determine the ability of these hempseed hydrolysates to inhibit lipid oxidation. Their applicability in food systems could be observed as they acted in a dose dependent manner to prevent lipid oxidation from occurring across a 7-day period. Overall, 0.5% AHM-10 and AHPI-10 was proven to be most effective and are applicable to inhibit oxidation in other food systems.
The second chapter of this research further allows for the observation of the previously selected hempseed hydrolysates to act as antioxidants in food systems, specifically in ground meat. Beef and turkey meatballs were prepared with the incorporation of AHM10 and AHPI10 at a selected concentration to observe their effect on oxidation levels across 14 days under refrigerated conditions. The quantification of primary and secondary oxidation products again allowed for the determination of hempseed hydrolysates’ ability to inhibit lipid oxidation. Moisture content, total lipid quantification and fatty acid composition allowed for a better understanding of the lipid profile of both meat systems. Sensory analyses were completed on day 1 and day 14 to determine the effect of hempseed hydrolysates on the organoleptic properties of the meat systems. The antioxidant efficacy of hempseed hydrolysates in food model systems was necessary to determine for their use as natural alternatives opposed to synthetic antioxidants such as BHA and EDTA
A Survey of Fungal Communities Harbored in Leaves of Agroforestry and Wild Criollo Cacao (Theobroma cacao L.) in Southern Belize
No full textTheobroma cacao L. (Malvaceae) is the main source of chocolate and cocoa related products. Around 60 countries in the pantropical region are involved in cacao production, and it is the main source of livelihood for approximately 60 million people. The cacao industry faces significant challenges from various pests and diseases that threaten the livelihood of subsistence farmers, who produce 90% of the world’s cacao. The first chapter investigates the impact of key cacao diseases, particularly in the Caribbean and Central America, focusing on their biological and environmental implications. The most prevalent pathogens discussed included Peronophythora, Moniliophthora, and Ceratocystis species, along with their economic consequences on global cacao markets. Chapter two explores the endophytic species associated with Criollo varieties. Putatively diseased leaf samples were collected from Criollo trees found at the Belize Foundation for Research and Environmental Education (BFREE) during two growing seasons (wet and dry). The Criollo sampled from the private protected area were part of a sub spontaneous population that were likely cultivated by early human civilization such as the Mayas. The culture dependent approach was used to get axenic fungal cultures. Mycelia from the cultures were used for DNA extraction and amplification, targeting the ITS region. Sequences were trimmed using the SangeranalyseR package in the R software, taxonomy were assigned using the UNITEver10 database. The sequences were also clustered into 97% similarity and the genera were matched to their primary lifestyle using FungalTraits. Ascomycota was the only fungal phylum identified in the dry season samples. In contrast, Ascomycota was the dominant phyla in the wet season however there was slightly more diversity, with Basidiomycota and Mucoromycota also being detected albeit in lower percentage. The findings provide baseline information for the important pathogenic species associated with criollo cacao and the need for integrated disease management and genetic improvement programs in securing the future of cacao cultivation in the face of ongoing challenges
Low-Cost Melt Pool Monitoring in Wire Arc Additive Manufacturing
No full textWire-Arc Additive Manufacturing (WAAM) is an emerging metal manufacturing technology that utilizes welding processes to build large-scale components in significantly reduced timeframes at lower costs with less material waste. However, maintaining consistent part quality remains a challenge due to variations in weld bead size, shape, and overall deposition characteristics. The enclosed research explores the development of a low-cost melt pool monitoring solution using readily available and inexpensive hardware and opensource software to analyze the deposition process and identify observable weld characteristics from an optical camera feed. The system’s effectiveness was evaluated by testing various weld parameters, introducing controlled defects, and using different materials to assess the correlation between melt pool behavior and process conditions. Post-processing of the recorded frame data was conducted using a combination of traditional image analysis techniques and machine learning algorithms to extract data on weld features and establish relationships between weld parameters and visual melt pool characteristics. The final camera system utilized a neutral density filter and low exposure times to mitigate the arc flash from the deposition process. The melting of the welding wire into the melt pool, the solidification front, and the arcflash itself were visible in the video frames. These components were detected by a machine learning algorithm and the data about their size and location within the video feed were used to compare the differences in the feed when weld parameters were changed
