The research in this thesis concentrates on investigation of the ecology of Arundinaria species for restoration purposes. Arundinaria species are key components in the canebrake ecosystem that was once prominent in the southeastern United States. Arundinaria still occurs as an understory component of bottomland hardwood forests, but with intense agricultural development and urbanization over the past 200 years, canebrakes are now a critically endangered ecosystem with greater than 98% loss. Specifically the thesis addresses the establishment of Arundinaria with other plant species and site preparation techniques. This study indicated that A. gigantea planted into plots dominated by non-native plants benefited significantly more from site preparation (soil tillage, herbicide application) than cane planted into native-species-dominated assemblages. The last portion of the research examined effects of inundation on A. gigantea and A. tecta. Arundinaria tecta appeared to be more flood tolerant than A. gigantea, reflecting habitats in which these species are known to occur.

Mouse hepatocytes in primary monolayer culture (4 hr) were exposed for 10 min at 37°C to anisosmotic medium of altered NaCl concentration. Hepatocytes maintained constant relative cell volume (experimental volume/control volume) as a function of external medium relative osmolality (control mOsm/experimental mOsm), ranging from 0.8 to 1.5. In contrast, the relative cell volume fit a predicted Boyle-Van't Hoff plot when the experiment was done at 4°C. Mouse liver slices were used for electrophysiologic studies, in which hepatocyte transmembrane potential (Vm) and intracellular K+ activity (aKi) were recorded continuously by open-tip and liquid ion-exchanger ion-sensitive glass microelectrodes, respectively. Liver slices were superfused with control and then with anisosmotic medium of altered NaCl concentration. Vm increased (hyperpolarized) with hypoosmotic medium and decreased (depolarized) with hyperosmotic medium, and ln [10(experimental Vm/control Vm)] was a linear function of relative osmolality (control mOsm/experimental mOsm) in the range 0.8-1.5. The aKi did not change when medium osmolality was decreased 40-70 mOsm from control of 280 mOsm. Similar hypoosmotic stress in the presence of either 60 mm K+ or 1 mm quinine HCl or at 27°C resulted in no change in Vm compared with a 20-mV increase in Vm without the added agents or at 37°C. We conclude that mouse hepatocytes maintain their volume and aKi in response to anisosmotic medium; however, Vm behaves as an osmometer under these conditions. Also, increases in Vm by hypoosmotic stress were abolished by conditions or agents that inhibit K+ conductance.

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The current study examined experiential avoidance (EA) as an explanation for parental overprotectiveness, a behavior often found among parents of anxious children. EA parenting theory posits that parents engage in overprotective behaviors in order to reduce their own anxiety. In order to test the theory, mothers’ electrodermal activity (EDA) and blindly-coded overprotective behaviors were examined when a child with SAD was engaged in a reading performance task. In line with EA theory, it was hypothesized that EDA levels would increase before an overprotective behavior (OB) occurred and decrease afterwards as a result of decrease in anxiety. The sample consisted of mothers with a child diagnosed with SAD (n=5) and mothers with a child with no diagnoses (n=5). Each mother-child dyad participated in an ABAB design protocol consisting of a baseline period, two 10-minute reading tasks, and a recovery period between the two tasks. Although mothers of both groups displayed OBs, mothers of children with SAD displayed OBs more often. In addition, mothers of children with SAD displayed more promotion of avoidance while mothers of normal control children displayed higher frequencies of control over the reading task. The EDA activity that surrounded the first occurrence of any coded OB was examined. Contrary to the hypothesis, all mothers (regardless of child’s anxiety status) displayed similar trends in their EDA data, with levels increasing but then decreasing shortly before an OB behavior occurred, rather than afterwards. However, one mother with an elevated social anxiety score revealed an EDA pattern similar to what was hypothesized. Possible explanations for these alternate findings are discussed and include a multidisciplinary conceptualization. The study’s findings hold theoretical and practical implications, particularly for parent training in the treatment of childhood anxiety disorders. Limitations such as small sample size and directions for future research are discussed.

Resistive random access memory (RRAM), based on a two-terminal resistive switching device with a switching element sandwiched between two electrodes, has been an attractive candidate to replace flash memory owing to its simple structure, excellent scaling potential, low power consumption, high switching speed, and good retention and endurance properties. However, due to the current limited understanding of the device mechanism, RRAMs research are still facing several issues and challenges including instability of operation parameters, the relatively high reset current, the limited retention and the unsatisfactory endurance. In this study, we investigated the switching mechanisms, conditions and applications of oxygen vacancy (Vo) filament formation in resistive memories. By studying the behavior of conductive Vo nanofilaments in several metal/oxide/metal resistive devices of various thicknesses of oxides, a resulting model supported by the data postulates that there are two distinct modes of creating oxygen vacancies: i) a conventional bulk mode creation, and ii) surface mode of creating oxygen vacancies at the active metal-dielectric interface. A further investigation of conduction mechanism for the Vo CF only based memories is conducted through insertion of a thin layer of titanium into a Pt/ Ta2O5/Pt structure to form a Pt/Ti/ Ta2O5/Pt device. A space charge limited (SCL) conduction model is used to explain the experimental data regarding SET process at low voltage ranges. The evidence for existence of composite copper/oxygen vacancy nanofilaments is presented. The innovative use of hybrid Vo/Cu nanofilament will potentially overcome high forming voltage and gas accumulation issues. A resistive floating electrode device (RFED) is designed to allow the generation of current/voltage pulses that can be controlled by three independent technology parameters. Our recent research has demonstrated that in a Cu/TaOx/Pt resistive device multiple Cu conductive nanofilaments can be formed and ruptured successively. Near the end of the study, quantized and partial quantized conductance is observed at room temperature in metal-insulator-metal structures with graphene submicron-sized nanoplatelets embedded in a 3-hexylthiophene (P3HT) polymer layer. As an organic memory, the device exhibits reliable memory operation with an ON/OFF ratio of more than 10. / Ph. D.

Seven experimental trials were conducted to develop and use novel techniques to examine the relationships between pre- and post-hatch physiological parameters in the progeny of young broiler breeders. Trials 1, 2 and 3 together examined the safer and effective use of transponders to determine embryonated egg air cell temperature (Temb) as an estimation of broiler embryo temperature during incubation, and to subsequently calculate eggshell water vapor conductance (GH2O), specific GH2O (gH2O) and GH2O constants (KH2O) in modern broiler strains. Trials 4 and 5 together examined the relationships of early, middle and late post-hatch growth quality parameters and tissue nutritional profiles of broilers with the corresponding Temb, GH2O, gH2O and KH2O. Furthermore, Trials 6 and 7 together examined the changes in nutritional profiles and histological structures of the broiler embryonic pipping muscle between 15 and 19 days of incubation. Based on the results from Trials 1, 2 and 3, it was concluded that transponders may be effectively implanted in the embryonated egg air cells with minimal invasion to the broiler embryo to efficiently determine Temb, and to subsequently calculate GH2O, gH2O and KH2O of modern broiler strain eggs during incubation. The results from Trials 4 and 5 also suggested that within physiological limits, an increased gH2O results in increased embryo metabolism, which subsequently increases growth and yolk sac absorption in the corresponding broiler chicks through 3 days post-hatch. Moreover, it was also observed that a higher gH2O was negatively associated with chick hydration status on day 28 post-hatch; although such effects were not observed through day 48 of the post-hatch grow out period. It was concluded that the effects of gH2O on post-hatch broiler physiology may be more pronounced during early and middle post-hatch periods and may subside as the chick reaches marketing age. Furthermore, the results from Trials 6 and 7 indicated that changes in the nutritional profiles of the pipping muscle occur in accordance with corresponding changes in liver metabolism, and that these together with associated morphological changes in the pipping muscle, as observed through histological techniques may be critical for the broiler embryo’s preparation for hatch.

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