Doctor of Philosophy (PhD), Wright State University, 2009, Biomedical Sciences PhD

Separation from the maternal attachment figure, particularly when it occurs in a novel or threatening environment, reliably increases pituitary-adrenal activity in a number of species, and is thought to increase later susceptibility to psychopathology in humans. However, little is known about the central mechanisms mediating these effects. Therefore, I investigated cortisol and ACTH levels in plasma, corticotropin-releasing factor (CRF) mRNA expression in the hypothalamic paraventricular nucleus (PVN), and c-Fos activity in a circuit [medial amygdala (MeA)- bed nucleus of the stria terminalus (BNST)] thought to drive pituitary-adrenal activity during exposure to psychological stressors, as well as in the PVN. Measurements were taken in 16 (+/-1)-day-old infant guinea pigs (Cavia porcellus) during maternal separation, exposure to a novel environment, and exposure to both separation and a novel environment. Levels of plasma cortisol and ACTH, and PVN CRF mRNA expression were elevated only when animals were exposed to both separation and novelty. The putative MeA-BNST circuit was activated during exposure to novelty regardless of whether or not the animals were separated, and c-Fos activity in the PVN was elevated during separation regardless of whether infants were in a novel environment. In sum, there were effects due only to separation; others due only to novelty; and some due to both. These results suggest that CRF activity in the PVN can account for changes in pituitary-adrenal activity during separation in a novel environment. Further, it appears that the effect of novelty on the hypothalamus is mediated at least in part by a circuit from MeA to BNST to PVN. However, other factors appear to mediate activation of the PVN during separation from the attachment figure in a familiar environment, and the lack of activation in the PVN when the attachment figure is present in a novel environment.

Committee: Michael Hennessy Ph.D. (Advisor); James Lucot Ph.D. (Committee Member); David Cool Ph.D. (Committee Member); Dragana Claflin Ph.D. (Committee Member); Patricia Schiml-Webb Ph.D. (Committee Member) Subjects: Biomedical Research; Developmental Psychology; Psychobiology

Doctor of Philosophy, The Ohio State University, 2003, Horticulture and Crop Science

Common groundsel (Senecio vulgaris L.) is an annual weed of Mediterranean origin that has become a worldwide pest in many crop production systems, including small fruit crops like strawberry. Management of common groundsel has been difficult because of its tolerance of many control measures and resistance to some herbicides, and because of inadequate or conflicting information about its biology. Studies were conducted in Ohio to determine the effect of common groundsel's maternal environment on seed dormancy, describe the pattern of seedling emergence and seed persistence, and to evaluate the response of common groundsel and strawberry to herbicides. Experiments were conducted using local seeds and seeds collected along a 700-km transect from Michigan to Kentucky. Freshly matured seeds collected from sites along this transect differed in germination response to temperature, but when plants from these sites were grown in a common environment the seeds responded uniformly to temperature. In growth chamber studies, seeds maturing on plants growing in cold short day conditions were mostly dormant whereas seeds produced on plants in warm long day conditions were mostly non-dormant. Changing temperature conditions from warm to cold increased seed dormancy, especially when the change occurred in early reproductive stages. The dormancy status of buried seeds varied throughout the year, mostly in response to soil temperature. Seedling emergence was limited by both rainfall and temperature but there was an interaction with tillage. A logistic regression model demonstrated that in tilled soil, emergence was stimulated by small amounts of rainfall, but in no-till conditions about ten-times as much rainfall is required to stimulate emergence. Nearly all buried seeds germinated or died during two years of burial in soil. In newly established strawberries, common groundsel was controlled with the herbicide sulfentrazone (N-[2,4-dichloro-5-[4-(difluoromethyl)-4,5-dihydro-3-methyl-5 (open full item for complete abstract)

Committee: Doohan Douglas (Advisor) Subjects: Agriculture, Agronomy

Doctor of Philosophy, Case Western Reserve University, 2010, Social Welfare

At any given time there are many thousands of mothers in the United States who have a history of traumatic childhood experience. In a community sample of 218 biological mothers the relationship between severity of maternal history of childhood trauma and quality of home environment provided for children was examined. The study also explored the impact of current exposure to violence, current substance use, perceived social support, and avoidant coping style on levels of parenting stress experienced, and asked whether parenting stress mediated the relationship between severity of maternal history of childhood trauma and the quality of home environment provided children. The study was a secondary data analysis, and data were analyzed using hierarchical multiple regression. In this sample, severity of history of maternal childhood trauma was not found to predict quality of home environment provided children. However, increased maternal verbal ability, higher levels of maternal mental health, higher income, and fewer children < 18 years old living in the household did predict increased quality of home environment provided. Increased levels of perceived social support and of maternal mental health predicted lower levels of parenting stress, though current exposure to violence, current substance use, and avoidant coping were not predictive of parenting stress. An increased incidence of potentially traumatogenic experiences in childhood was positively associated with higher levels of parenting stress, and higher levels of parenting stress, in turn, were associated with a diminished quality of home environment provided children. Implications of findings for future research and for social work policy and practice are discussed.

Committee: Elizabeth Tracy PhD (Committee Chair); Mark Singer PhD (Committee Member); Sonia Minnes PhD (Committee Member); Lynn Singer PhD (Committee Member) Subjects: Social Work