University of Tennessee Institute of Agriculture
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Deep Learning-Based Time Series Methods for Predictive Understanding of River Ice Breakup in North American Cold Regions
Get PDFThe annual melting of river ice in Arctic regions presents a significant hazard, leading to ice jam flooding (IJF), ecosystem disruption, property damage, and risks to local communities. Accurately forecasting river ice breakup is essential for mitigating these risks, ensuring safe transportation, and deepening our understanding of Arctic river ecosystems.
This research first develops a deep learning-based approach to predict river ice breakup using meteorological and hydrological data. A long short-term memory (LSTM) model, trained on Daymet meteorological inputs and static hydrological data from the pan-Arctic catchment database (ARCADE), predicts breakup timing across 33 locations with an average error of 5.40 days. Additionally, seasonal forecast ensembles from the Copernicus Climate Data Store (CCDS) are incorporated to assess the model\u27s capability in predicting future events. Shapley value analysis is employed to interpret the time-varying input contributions.
Building upon these findings, the study expands to 93 locations across Alaska and Canada and leverages CMIP6 and NEX-GDDP Earth system model (ESM) outputs to serve as inputs, allowing for future projections under four socio-economic pathway scenarios (SSPs). Results indicate that under more extreme warming scenarios, river ice breakup occurs earlier in the season, with the possibility that Arctic rivers may fail to freeze entirely in the distant future due to rising temperatures and increasing uncertainty in the region.
The role of atmospheric rivers (ARs) in river ice breakup is also investigated. ARs, capable of transporting vast amounts of moisture, have a notable impact on the Alaskan climate. Analysis across 26 locations reveals that ARs elevate local air temperatures for over a week, contribute to 40% of annual precipitation, and account for a majority of extreme precipitation events. A physics-based analysis shows that winter precipitation delays ice breakup, whereas precipitation near the breakup date has little effect.
This research contributes to improving river ice breakup forecasting and understanding its climate-driven variability. Future work will refine predictive models and explore additional climate drivers affecting Arctic hydrology
An Exploration of How Congruence Between Students and Their Academic Environment Impacts Student Success
Get PDFThis study examined the relationship between person-environment fit (P-E fit) and student outcomes at public, two-year colleges (PTYCs) using Holland’s (1997) theory of vocational personalities and work environments as the framework for defining “congruence.” The research was conducted at Pellissippi State Community College, a large PTYC in the southeastern United States, with a sample of 1,257 students who completed the Interest Profiler Short Form (IP Short Form) during enrollment. Two analyses were conducted to evaluate the role of congruence in student success: (1) a sequential multiple linear regression to test its predictive value for first-semester GPA, and (2) a sequential logistic regression to assess its impact on fall-to-fall retention. Cultural and precollege characteristics were included in the analyses to examine whether congruence predicted these outcomes beyond these variables. Congruence scores were calculated by assigning RIASEC types to both students and their courses and applying the C Index to generate fit scores, which were then averaged across classes. The findings revealed that congruence was not a significant predictor of either first-semester GPA or fall-to-fall retention, suggesting that other factors may play a more critical role in influencing these outcomes. This study contributes to the limited research on PTYC student success and offers insights into the applicability of Holland’s theory and P-E fit frameworks in higher education research
UNDERSTANDING UNDERGRADUATE MICROBIOLOGY FACULTY’S SYNCHRONOUS ONLINE COURSE DESIGN JUDGMENT WHILE LIVING THROUGH THE COVID-19 PANDEMIC
No full textThis qualitative, descriptive multiple-case study investigated the online teaching experiences of seven undergraduate microbiology faculty at public universities during the COVID-19 pandemic. This study investigated instructors unfamiliar with synchronous online course development to (a) describe how they designed online courses during the COVID-19 pandemic, (b) discover what influenced how they designed those courses, and (c) detail why they made the respective design decisions. It leaned into the theoretical tenets of social constructivism and followed a multiple case study approach, relying on interviews and document analysis. Instructors were recruited through criterion-based convenience sampling and snowball methods. They were faculty who traditionally taught in-person large-sized microbiology courses prior to the COVID-19 pandemic. They transitioned to an online learning modality during the pandemic. The study findings revealed that participant instructors exercised similar overlapping design judgments as they redesigned their courses during the COVID-19 pandemic. Participants indicated that they developed synchronous online courses within the institution’s learning management systems, integrated open educational resources, and utilized various teaching tools, including digital games. They encouraged students to interact and work in teams, enabling them to co-construct their learning. However, instructors wrestled with balancing many teaching demands against anxious students’ expectations. Instructors also grappled with ways to accommodate diverse students’ needs while promoting equity, diversity, accessibility, and inclusion in an online learning environment. Most notably, there was tension between finding efficient ways to maintain rigor and protect assessment integrity while empathizing with students. As demand for synchronous online learning increases, the study’s findings aim to make explicit the connection between design judgment research and practice. The goal of this study was to draw attention to instructors’ unconscious assumptions, behaviors, attitudes, thoughts, experiences, beliefs, culture, goals, and skills that influenced design decisions, particularly during disruptive events such as the COVID-19 pandemic. It aimed to empower the instructional design community members with awareness and sensitivity to what instructors bring with them to the collaborative design process
Strategies For Improved Establishment of Native Forages
Get PDFUtilization of various cover crops during native warm-season grass (NWSG) establishment presents an opportunity to mitigate the lost forage production that has come to be a hallmark of NWSG establishment. Successful application of a productive cover crop could help overcome a major barrier to NWSG adoption. Another potential benefit to the use of cover crops is their ability to suppress weeds. Studies addressing the use of various cover crops in the Southeastern US have thus far largely focused on the use of cereal crops as companion crops during NWSG establishment which are then harvested for hay upon reaching maturity. The trials presented in the following work were developed to evaluate the use of nurse crops during NWSG establishment to offset loss of forage production during the seedling year. The first study evaluated the use of two nurse crops, a warm season diversity blend (DB) (Ray’s Crazy Mix, Southeast AGRISEEDS, Rome, GA), and browntop millet (BTM) (Urochloa ramose (L.) Nguyen), to reduce weed pressure and provide a source of livestock forage during the seedling year as well as the effects of grazing these nurse crops on the first-year establishment of the co-planted NWSGs (Chapter 2). The second study design looked to elucidate the role of thatch groundcover depth and composition on suppressing weeds and NWSG seedling recruitment (Chapter 3). The final trial utilized the controlled environment of a greenhouse to evaluate the sensitivity of NWSG germination and early seedling development to soil phosphorus (P) and pH levels (Chapter 4). In the first trial, both nurse crops reduced weed pressure while also reducing NWSG recruitment. Grazing did not affect NWSG recruitment but was successful at reducing weed pressure and allowing more light to penetrate the canopy. In the second trial, thatch depth played a driving role in NWSG recruitment while thatch type had no effect. Imazapic synergized with grazing to reduce weed canopy cover (WR) compared to the CTRL and non-grazed treatments. In the greenhouse trial soil increasing P generally benefited BBS seedling growth metrics, while pH as low as 4.5 had no effect on seedling germination, tillering, or root growth, but did interact with P to increase plant height. Mid-season clipping negatively affected end of season above ground plant height, overall plant mass, and tiller number, but did not affect root length, mass, or root to shoot ratio
Innovative Lignin Nanoparticle Manufacturing and Applications in Sustainable Packaging Solutions
Get PDFThe extensive use of synthetic materials, particularly plastics and per- and polyfluoroalkyl substances (PFAS), has led to severe environmental issues, including microplastic contamination, and elevated PFAS levels in water resources. Additionally, plastic waste, such as sheets, ropes, and nets, poses significant threats to wildlife. These challenges underscore the urgent need for sustainable, degradable alternatives. Lignin, which is biodegradable, inherently hydrophobic due to its low hydroxyl content, and UV-resistant owing to its polyaromatic structure, presents a promising solution. However, the complex and non-uniform composition of industrial lignin limits its practical applications. Reducing lignin to the nanoscale through mechanical processes eliminates the need for solvent chemicals, facilitating scalable and sustainable production.
This study investigated the manufacturing of lignin micro- and nanoparticles (LMNP), focusing on the effects of temperature and solid content during ultrafine grinding (UFG), as well as the associated electricity consumption producing 1 kg LMNP. Additionally, the use of LMNP as functional agents in biomass-based food packaging and tableware applications was explored. The impact of processing temperature on nanoparticle formation was systematically examined. Results revealed that elevated temperatures (~70°C) accelerated particle size reduction, whereas lower temperatures (~0°C) resulted in smaller final particle sizes. Increasing the solid content significantly reduced energy consumption during processing.
The LMNP suspension was then applied to paper and hot-pressed to form a dense, smooth film. Under optimized conditions (160°C, 3 MPa, and 3 minutes), the lignin film exhibited water resistance for over an hour and oil resistance for 25 minutes. To address aesthetic concerns, a sandwich structure was introduced, embedding the lignin composite between two paper sheets. This design enhanced tensile strength by 50% while maintaining water- and oil-resistant properties. Furthermore, a dry processing method was developed by blending LMNP with dry fibers, followed by direct hot pressing. This approach demonstrated energy and water efficiency compared to wet molding method, offering a viable pathway for sustainable, high-performance applications in green packaging
Investigating Freshwater Mussel Disease and Mortality in the Clinch River Within a Population Ecology Framework
Get PDFFreshwater mussels (order Unionida) play an important role in aquatic ecosystems, providing essential ecosystem services to humans and wildlife. The United States harbors the highest diversity of mussels globally, yet nearly 70% of known species are considered imperiled. The Clinch River, a major biodiversity hotspot for mussels in the Unites States, has experienced recent mass mortality events (MMEs) dramatically affecting multiple species. Studying MMEs is inherently challenging due to their unpredictability and the frequent scarcity of reference data on mortality dynamics of affected populations. In this dissertation, we fill knowledge gaps by elucidating patterns, processes, and factors influencing mortality within mussel populations in the Clinch River. We use a combination of pathological, toxicological, microbiological, and ecological assessments to identify potential causal agents, detect environmental risk factors, and characterize demographic structure of affected individuals. We also apply epidemiological concepts to analyze archived shells and gain etiological insights into past MMEs. This research provides critical insights into the disease and mortality dynamics influencing mussel populations. Lastly, we discuss lessons learned from historical mortality events and propose strategies to enhance response to future MMEs
EXPLORING RICKETTSIAL BACTERIA PRESENCE IN TICKS AND CHARACTERIZATION OF THEIR INTERACTIONS WITH MAMMALIAN CELLS
No full textTicks are blood feeding arthropods that harbor bacterial endosymbiont. Several studies have identified rickettsial endosymbionts in hard ticks. However, little is known about the presence of rickettsial bacteria in soft ticks. Ticks also transmits several rickettsial pathogens to humans including Rickettsia parkeri, the causative agent of R. parkeri rickettsiosis. In these studies, we noted the presence of Occidentia species, designated as Occidentia-like species, in a soft tick O. turicata americanus. In addition, we characterized the interactions of R. parkeri with endothelial cells and macrophages. We used quantitative real-time PCR, sequencing, fluorescent microscopy, live/dead staining, siRNA-mediated silencing, protein array analysis, bioinformatics, and cell culture studies in this study. In the first study, we noted that the Occidentia-like species was present in all developmental stages of O. turicata americanus and in different tick tissues including ovaries, synganglion, guts and salivary gland. In addition, the levels of Occidentia-like species was induced by blood feeding. In the second study, we noted a reduced bacterial burden of R. parkeri in macrophages and tick cells treated with AsmA antibody compared to control-IgG treated cells. Additionally, we noted that the bacterial burden for R. parkeri asmA mutant was significantly lower than the wild type at later time points (day 3, 4, and 5 post-infection). This study showed importance of AsmA in R. parkeri survival in both tick and mammalian cells was proven. In the third study, a protein array for human metabolic pathways showed the upregulation of CD157, a molecule that relies on nicotinamide adenine dinucleotide (NAD+) for its functions in endothelial cells upon R. parkeri infection. Moreover, we observed that R. parkeri infection affected NAD+ metabolism in the host cell. Various strategies of NAD+ treatment revealed the importance of NAD+ in R. parkeri-host interactions. Moreover, siRNA-mediated silencing of CD157 showed its involvement in the regulation of NAD+ metabolism and R. parkeri infection. In summary, these studies not only provide molecular insights on the mechanisms modulated by R. parkeri for its survival in mammalian cells but also lead to the development of strategies to target this and perhaps other rickettsial pathogens
DUAL USE OF BONE SCAFFOLD FOR ANTIBIOTICS DELIVERY DELAYS THE ONSET OF OSTEOMYELITIS
Get PDFOsteomyelitis (OM) poses significant treatment challenges, making dual platform implants a promising technology. This study introduces a dual platform device designed to promote bone healing and deliver antibiotics to prevent OM, addressing the limitations of current osteogenic implants that lack antimicrobial properties. 23 goats were allocated into four treatment groups: 1) SA: scaffolds loaded with Vancomycin (n=5); 2) SB: scaffolds with bacteria (UAMS-1) (n=6); 3) SBA: scaffolds with Vancomycin and bacteria (n=6); 4) NS: native scaffolds (n=6). A segmental defect was created on the right tibia of each goat, followed by scaffold implantation according to the treatment group. Goats were monitored for 90 days. Biweekly radiographs, post-euthanasia CT imaging, and bacteriology on scaffold and soft tissue were performed. Radiographs and CT were scored by a blinded radiologist for OM and Healing. 16 goats reached the study endpoint. All SB group goats were removed early due to OM complications. Radiograph OM scores differed significantly across groups, with SA and NS showing similar outcomes, while SB and SBA differed from other groups. Healing scores did not differ significantly between SA, SBA, and NS (p = 0.3675). CT comparison findings aligned with radiograph OM scores but differed significantly between methods (p = 0.0238) indicating that these methods assess disease severity differently. Both radiographs and CT provided consistent healing assessments with no significant difference between methods (p = 0.3332). These results indicate that Vancomycin-loaded scaffolds offer a distinct advantage in contaminated surgeries, underscoring the importance of antibiotic integration in treating osteomyelitis
The Impact of a Virtual Reality (VR) Professional Development on Agricultural Teachers’ Intent to use Virtual Reality for Teaching International Agriculture Topics
No full textDue to society\u27s increasing global interconnectedness, there is a growing need for more globally aware young leaders in agriculture. Because of this need, there is a demand for more internationalized school-based agriculture (SBAE) education, as SBAE students need to be prepared for the globalized agricultural workforce. Despite this demand, there is a lack of international agricultural resources and experiences. This research aims to propose and assess an innovative solution to fill this gap and promote international agricultural literacy among SBAE students in Tennessee and Nebraska. This thesis evaluates the impacts of a VR-integration professional development (PD) program on SBAE teachers’ perceptions and intentions to use virtual reality technology to teach international agricultural topics. A VR international agriculture lesson was demonstrated to SBAE teachers during the PD. The lesson was developed for the PD using 360-degree videos captured by a graduate student on a study-abroad trip in Cambodia. The videos were narrated by agricultural students on the trip, showcasing diverse agricultural production, agricultural education, and agritourism experiences in Cambodia.
A qualitative and quantitative study was conducted to evaluate the concept of using VR to teach international topics. The qualitative study aimed to explore participants’ perceptions and intentions to use VR to teach international topics using post-PD focus groups. The purpose of the quantitative study was to describe the confidence and intentions of PD participants from Nebraska and Tennessee to use VR to teach international agriculture topics before and after participating in a VR-integration professional development (PD) program. Findings show that participants had positive perceptions toward using VR to teach international topics and viewed the concept as a novel method for teaching an otherwise neglected topic. The findings from these studies provide valuable insight into VR\u27s potential role in overcoming barriers to SBAE international experiences
Precision Livestock Farming in the Broiler Industry: A Producer Survey on Implementation and Extension Education
Get PDFPrecision Livestock Farming (PLF) technology has the potential to revolutionize commercial poultry production by offering real-time monitoring and alerts when production conditions change. While several publications have identified the potential benefits of PLF in broiler production, adoption rates remain low. It is possible that low adoption is correlated to a gap in information transfer between PLF research and producers. The University of TN hosted a one-hour PLF module during the 2023 Tennessee Master Poultry Producer program based on results from a producer needs assessment identifying poultry producers’ interest in PLF education topics. This module was designed to introduce PLF to poultry producers, but did not provide resources for currently marketed technology. Because of this, a second survey was distributed in 2024 to identify producer needs for a multi-day PLF short course. This survey identified a lack of familiarity with PLF among broiler producers. Producers also expressed an interest in learning about PLF if Extension were to offer a workshop. Producer needs for PLF technology are focused on improving income and productivity without diminishing the welfare of the flock. From this survey data, we created a producer short course designed to increase broiler producers’ knowledge of PLF and allow them to make informed decisions about whether to implement PLF into their productions. This course offered insight to PLF technology applicable to poultry production, research advancements, implementation, and currently marketed technology. This thesis presents survey data representing producers needs for PLF training, producer perspectives on PLF technology in broiler production and the development of a producer short course for PLF educatio