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Meeting minutes of the Tennessee Tech University Administration Council.

Residual Dipolar Couplings (RDCs) have been used in the structural determination of biomolecules, pharmaceutical molecules, and small organic molecules in solution. Determining the structure of metal-ligand complexes in solution may also benefit from the application of dipolar couplings. X-ray crystallography can be used to determine the structure of metal ligand complexes in solid state. Chiral catalyst ligands and biologically active ligands and their metal complexes are both most active in solution making structural determination in solution of direct interest for these applications. This study focuses on determining the structure of NaphthoQuinoneSulfonic Acid Benzyl Thiosemicarbazone (NQSA-BTSC) ligand, NaphthoQuinoneSulfonic Acid Phenyl Thiosemicarbazone (NQSA-PTSC) ligand, (1R,2R)-N,N′-1,2-Cyclohexanediylbis(2-pyridinecarboxamide) also known as (R,R)-DACH-pyridyl Trost ligand, and their metal complexes in solution. RDCs have been proved to be a useful method in determining molecular shapes in solution. This is achieved by using the strain aligned gel (SAG) method. Anisotropic media of poly methyl methacrylate (PMMA) and polyvinyl acetate (PVAC) were used to generate an anisotropic environment for examining ligands and metal ligand complexes. This anisotropic environment allows us to determine RDCs in solution by NMR spectroscopy and used to find the three dimensional structure of these complexes through the singular value decomposition (SVD) methodology currently employed for other molecules.

Raccoons (Procyon lotor) and Virginia opossums (Didelphis virginiana) are generalists with wide distributions that overlap extensively. Due to high niche overlap and expectation of competition, studies to define the degree of ecological overlap between the species have been numerous, but no population limiting factor has been identified. I used compositional analysis to determine the habitat characteristics important to each species individually and in relation to the other species. Concurrently, I used occupancy modeling to determine which habitat characteristics were important to probabilities of detection and occupancy for raccoons and Virginia opossums. Track stations, hair traps, and camera traps were used to detect raccoons and Virginia opossums 8 March – 11 June 2015 and 24 February – 8 May 2016 in Arkansas. Raccoons and Virginia opossums, along with 6 other furbearing species, were the most common species detected in both years. Using compositional analysis, ground cover characteristics were ranked in the same order of importance for both species when compared to availability of those characteristics across the landscape. Raccoons selected ground cover characteristics the same when Virginia opossums were present. Virginia opossums selected ground cover differently when raccoons were present in 2015, but in 2016, selected ground cover the same. Virginia opossums did not select woody ground cover with the same likelihood as litter and herbaceous ground cover in 2015, although the habitat characteristics were ranked in the same order. Occupancy modeling determined habitat characteristics important to detection and occupancy of raccoons and Virginia opossums individually. Both species had high, but imperfect, detection rates supporting the need for continued evaluation of occupancy using methods that account for false absences. In most cases, my results of relationships between the two species and habitat covariates support previous research. However, there were plausible explanations for the unexpected relationships between raccoons and Virginia opossums and habitat covariates measured in this study.

Advancing the field of fish ecology requires a shift in focus from describing patterns in species occurrences to understanding the mechanisms that regulate distributions and abundances across broad scales. For stream fish ecology, this includes understanding environmental mechanisms that regulate stream fish demographic processes at the scale of stream networks. Despite the fact that Banded Sculpin Cottus carolinae occupy a diversity of habitats and stream sizes across the southeastern United States, relatively little is known about demographic processes of this species. I studied annual demographic properties (reproduction, growth, and survival) of C. carolinae collected monthly from four sites distributed longitudinally along the Roaring River stream network in Tennessee to simultaneously describe life history attributes of the species and address network-scale environmental regulators of populations. C. carolinae lived for a maximum of four years, local populations were dominated by age-0 and age-1 individuals, females began reproduction after one year and spawned during December and January when an average of 398 ova were produced. Across sites, the onset of reproduction correlated with water temperature and spawning was synchronized across the stream network. Demographic tradeoffs in growth and survival were evident at an intermediate stream size, in which larger individuals were more robust but had a lower survival rate compared to the remaining three sites. Age-specific size structures showed limited evidence for a longitudinal pattern characterized by increasing overlap in the size of age-0 and age-1 fish at downstream sites. My work illustrates the potential for muted population responses to strong hydrologic gradients in streams and highlights the stability inherent with fish life history adaptations to natural environmental regimes across broad spatial scales.