University of Tennessee Institute of Agriculture
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Cataloging Livestream Episode 5: Cataloging Cartographic Materials (Atlases, Maps)
No full textThe Cataloging Livestream series features SIS professor Dr. Brian Dobreski demonstrating library cataloging tools and procedures in real time. Episode 5 covers cataloging cartographic resources, such as atlases and maps
Opioid-induced sleep disruption in C57BL/6J mice: A systems physiology perspective
No full textThis dissertation was motivated by the ongoing opioid epidemic and the substantial impact of opioids on sleep health. While opioids are well-documented sleep disruptors, their effects on sleep have been understudied. Sleep plays a key role in overall health, and is closely interrelated to many other physiological systems, including motor activity control and body temperature regulation.
The chapters of this dissertation investigate the dose-dependent effects of morphine and fentanyl on sleep amount and architecture. Given that sleep homeostasis is a tightly regulated and multifactorial process, this work also examines the dose-dependent effects of opioids on EEG power, motor activity, and body temperature. Although the dependent variables observed here have been studied previously, they are often studied independently. This dissertation adopts an integrative approach to investigate the interaction among the effects of opioids on sleep, motor activity, and body temperature. To address these objectives, male B6 mice were used to simultaneously record sleep/wake states, motor activity and subcutaneous body temperature. The interactions among the dependent variables were evaluated through mediation analysis, a statistical approach based on structural equation modeling.
Chapters 2 and 3 detail the effects of antinociceptive doses of opioids on sleep and EEG. Chapter 3 expands on this by exploring the dose-dependent effects and depicting four-point logarithmic dose-response curves of the effects of fentanyl and morphine on sleep, EEG power, motor activity and body temperature.
The findings presented in this dissertation offer novel insights into the mechanisms underlying opioid-induced sleep disruption, suggesting that in B6 mice this disruption is at least partially secondary to the opioid-induced increases in motor activity. Taken together, this work provides a new perspective through an integrative approach commonly used in systems physiology. The results shown here also underscore the importance of evaluating together opioid-induced adverse effects to better inform new strategies for the management of opioid-induced sleep disruption, pain management, addiction and overall opioid use
Urban Muslim Communities and Disaster Risk Reduction: Strengthening Faith-Based Collaboration in a Changing Climate
No full textAs urban areas face increasing disaster risks due to climate change, faith-based community organizations (FBCOs) play a crucial yet underappreciated role in enhancing community resilience and in disaster risk reduction (DRR). This research examines the role of local Muslim FBCOs in DRR in Knoxville, Tennessee, highlighting their contributions, challenges, and potential collaboration with emergency management agencies (EMAs). The study is guided by three primary objectives: assessing how the Muslim community and their leaders perceive the role of FBCOs in hazardous weather preparedness, response and recovery (PRR), exploring community perceptions of hazardous weather and climate change along with the influence of Islam and FBCOs on these perceptions, and finally evaluating FBCO leaders’ views on collaboration with local EMAs to develop more inclusive and effective DRR strategies.
A mixed-methods approach was used, involving semi-structured interviews with ten FBCO leaders, a survey of 82 members from the Knoxville Muslim community, and archival analysis of local disaster mitigation plans. The findings underscore the invaluable role that Muslim FBCOs play in providing social, spiritual, and material support to their community during times of need. However, these organizations face major barriers for providing comprehensive DRR support due to limited resources, a lack of disaster training, and competing priorities. Community perceptions of hazardous weather risks and climate change vary, with hazard preparedness levels influenced by familiarity with local hazards. Although religion (Islam) may influence individuals\u27 pro-environmental attitudes, this potential has yet to be leveraged by local FBCOs to enhance environmental awareness and disaster management. While government agencies possess the technical expertise for DRR, their engagement with diverse communities often falls short.
While this study is exploratory, it underscores the need to strengthen partnerships between FBCOs and EMAs to create inclusive, culturally responsive DRR strategies. By enhancing collaboration, increasing resource accessibility, and integrating FBCOs into formal emergency planning, disaster resilience can be improved in multicultural urban environments. This study contributes to the discussion on inclusive DRR strategies, promoting equitable, bottom-up approaches that acknowledge the role of FBCOs in building resilience
Investigating the chloroplast-to-nucleus signaling that regulates plasmodesmata- mediated intercellular trafficking in plants
No full textIntercellular communication via plasmodesmata (PD) is important for plant growth, development, and defense, yet its regulation remains poorly understood. Chloroplasts communicate information about the environment and the physiological state of the plant cell to the nucleus. Chloroplast-generated signals may change the expression of PD-related nuclear genes to regulate the trafficking of photosynthetic products and metabolites along with other molecules that act non-cell autonomously. We aim to identify the chloroplast retrograde signals that regulate intercellular trafficking via PD. Here, we show that tetrapyrroles, likely heme, regulate some aspects of PD-mediated intercellular trafficking. This regulation is not dependent on light. In addition to revealing the potential role of tetrapyrroles in regulating intercellular trafficking, we also revealed that the glucosinolates, a group of specialized metabolites best known for their roles in antimicrobial defense in select plant families, can act as signals to regulate PD-mediated intercellular communication. In contrast to previous reports, we did not identify any correlation between PD-mediated intercellular trafficking and the level of reactive oxygen species (ROS), the redox status of the chloroplast, or plastoquinone redox status. In a related study, we performed differential gene expression analyses and Gene Ontology (GO) analyses and then created protein-protein-interaction networks using differentially expressed genes (DEGs) encoding proteins. Understanding how tetrapyrroles, and in the broader sense chloroplast-to-nucleus retrograde signaling, control trafficking through PD could enable the engineering of plants to optimize carbon partitioning to various parts of the plant for higher yield or to limit pathogen spread. In toto, the studies presented in this thesis have advanced our understanding of the cellular players that regulate the movement of molecules and signals between plant cells, an indispensable portion of the cell-to-cell communication that the coordinated growth, development and environmental responses that are characteristic of and necessary for multicellularity
Implications of Dynamic Buying and Selling Patterns for Firm Performance
No full textThis dissertation examines strategic challenges in marketing, focusing on salesperson performance and customer retention. The first essay investigates the strategic implications of sales momentum by distinguishing between past success with non-customers (“hunting momentum”) and past success with current customers (“farming momentum”). Analyzing CRM data from a Fortune 500 firm, this study reveals that hunting momentum increases lead pursuit but lowers conversion likelihood, while farming momentum enhances conversions without affecting pursuit decisions. Experimental work further demonstrates that these effects stem from distinct attributions about past success, which shape future salesperson behavior. These findings highlight the need for managers to strategically intervene when salespeople experience hunting momentum to prevent inefficient pursuit of leads. The second essay explores the strategic impact of temporary consumption reduction, such as Dry January, on long-term customer retention and spending patterns. By analyzing transaction data from a major alcohol retailer, this study evaluates how firms can anticipate shifts in demand and leverage alternative products to sustain profitability. Together, these essays contribute to marketing strategy by identifying key drivers of sales effectiveness and customer retention, offering actionable insights for firms navigating dynamic market conditions
Enhancing Data Science Job Market Transparency: Salary Prediction and Skill Valuation
Get PDFThis dissertation investigates job market dynamics through machine learning and natural language processing applied to job posting data. The research aims to enhance labor market transparency by providing accurate salary predictions, insights into skills’ monetary value, and identification of high-demand skill combinations. Analysis utilizes a comprehensive dataset of Data Scientist job postings across the USA, focusing on the technical labor market to deliver actionable insights.
The first essay develops a robust salary prediction model leveraging both unstructured and structured job posting data. Textual information from job descriptions is transformed using various embedding techniques (Word2Vec, Doc2Vec, BERT, and OpenAI embeddings), while structured variables are extracted directly from job attributes. These features are processed through H2O Automated Machine Learning (AutoML), which evaluates multiple model families—including linear models, tree-based algorithms, and multilayer perceptrons— to create an optimized ensemble model. Our best model achieves a Mean Absolute Percentage Error (MAPE) of 16%, demonstrating strong predictive performance.
The second essay introduces a framework for estimating the monetary value of individual skills and skill combinations in Data Science. Using a quasi-experimental design, job postings are segmented into treatment and control groups based on the presence of specific skill terms, isolating each skill’s marginal impact on salary outcomes. The concept of skill complementarity captures synergistic effects where certain skill pairs yield higher salary premiums together than the sum of their individual contributions. These findings benefit multiple stakeholders: job seekers can target high-value skills, while employers can make informed decisions about recruitment requirements.
This dissertation advances labor market transparency by developing text-driven machine learning models for salary prediction and skill valuation. By integrating advanced analytics with large-scale labor market data, the research contributes to labor market analytics with data-driven insights for policymakers, employers, and job seekers, highlighting the importance of strategic skill development in our increasingly dynamic job market
RUSSULA, A MODEL TO STUDY ECTOMYCORRHIZAL FUNGAL DIVERSITY, DISTRIBUTION, AND ENVIRONMENTAL THREATS
Get PDFThe genus Russula (Russulales) is one of the most taxonomically diverse and ecologically significant groups of ectomycorrhizal fungi, forming mutualistic associations with all major lineages of ectomycorrhizal plants worldwide. However, limited understanding of their species-level diversity, ecology, and distribution makes it difficult to assess threats to Russula persistence. This work explores threats to fungal diversity in spruce-fir forests of the southern Appalachians, along with the diversity, distribution, and evolutionary history of Russula at both local and global scales. It was determined that soil lead (Pb) concentrations were negatively associated with ectomycorrhizal fungal diversity, including Russula in spruce-fir forests of the southern Appalachians. In this region, 30 species-level Russula clades were identified by utilizing a three-pronged approach that included fresh field collections, the identification of Russula OTUs from environmental sequencing efforts, and a revision of herbarium specimens. Soil manganese (Mn) concentration was the strongest factor influencing Russula occurrence, with 46% of the species analyzed showing a decline with increasing soil Mn concentrations. Individual Russula species occurrences were shaped by a variety of edaphic factors, highlighting their diverse ecological roles in the spruce-fir ecosystem. A global multilocus phylogenetic analysis of Russula subsection Xerampelinae revealed at least 23 species, including three new species: R. lapponica, R. neopascua, and R. olympiana. While some species in the subsection were distributed across the Holartic region, others were geographically restricted. Most species were found to be host generalists, with their evolutionary history likely influenced by the distribution and diversification of their primary hosts. This study highlights the significant impact of edaphic factors on Russula diversity. It also provides the first multilocus phylogenetic framework for Russula subsection Xerampelinae, revealing patterns of species diversity, host associations, and biogeographic distributions. These findings contribute to a deeper understanding of the ecological roles and evolutionary history of Russula, while highlighting broad threats to it and other ectomycorrhizal diversity
Synthesis, Structure, and Bonding of Macrocyclic Tetra-NHC Complexes of Iron and Cobalt
No full textN-heterocyclic carbenes (NHCs) are key ligands that have broad applications in organometallic chemistry. Several of their benefits stem from their ability to stabilize high oxidation states when bound to transition-metals. In the past two decades, NHC complexes have been developed to study oxidative processes such as nitrogen and oxygen transfer chemistry. Macrocyclic tetra-NHCs, where four NHC units form a cyclic structure, are particularly valuable for stabilizing metals due to their chelation effect. Their rigid structure enforces a well-defined coordination environment, making them highly effective in catalysis. While this growing field of macrocyclic tetra-NHC complexes is promising for studies on synthesis, reactivity, structure, and bonding, studies on this class of NHC still lag behind other poly-dentate NHC ligands.
Presented in this dissertation is an investigation of cyclic tetra-NHC complexes that shows: (1) the reactivity of an iron complex with organic azides, (2) synthetic investigation and structural observations of cobalt complexes, and (3) a synthetic approach to developing chiral macrocyclic tetra-NHC ligand precursors. Chapter two focuses on understanding the reactivity of a chiral tetra-NHC iron complex and organic azides, which form multiple district types of complexes. Chapter three highlights the structure and bonding of cobalt tetra-NHC macrocycles with multiple classes of these ligands. Lastly, chapter four explores the synthesis of new chiral tetra-NHC macrocycles