Thesis (M.A.)--West Virginia University, 2003. / Title from document title page. Document formatted into pages; contains iii, 58 p. : ill. Includes abstract. Includes bibliographical references (p. 30-32).

Thesis--M. Phil., University of Hong Kong, 1985.

The Multidimensional Generalized Graded Unfolding Model (MGGUM) is a proximity-based, noncompensatory item response theory (IRT) model with applications in the context of attitude, personality, and preference measurement. Model development used fully Bayesian Markov Chain Monte Carlo (MCMC) parameter estimation (Roberts, Jun, Thompson, & Shim, 2009a; Roberts & Shim, 2010). Challenges can arise while estimating MGGUM parameters using MCMC where the meaning of dimensions may switch during the estimation process and difficulties in obtaining informative starting values may lead to increased identification of local maxima. Furthermore, researchers must contend with lengthy computer processing time. It has been shown alternative estimation methods perform just as well as, if not better than, MCMC in the unidimensional Generalized Graded Unfolding Model (GGUM; Roberts & Thompson, 2011) with marginal maximum a posteriori (MMAP) item parameter estimation paired with expected a posteriori (EAP) person parameter estimation being a viable alternative. This work implements MMAP/EAP parameter estimation in the multidimensional model. Additionally, item location initial values are derived from detrended correspondence analysis (DCA) based on previous implementation of correspondence analysis in the GGUM (Polak, 2011). A parameter recovery demonstrates the accuracy of two-dimensional MGGUM MMAP/EAP parameter estimates and a comparative analysis of MMAP/EAP and MCMC demonstrates equal accuracy, yet much improved efficiency of the former method. Analysis of real attitude measurement data also provides an illustrative application of the model.

Not available / text

No description available.

No description available.

Effects of anxiolytic compounds of diverse chemical classes (chlordiazepoxide, buspirone, ritanserin, propranolol and BRL46470) on the behaviour of mice were examined in several animal models of anxiety. These models included social interaction by male mice in the animal's home cage and an unfamiliar neutral cage, the light/dark box and responsiveness of the mice to calls from predatory and non-predatory birds. Effects of anxiolytics were also examined in mice in the timid female paradigm, and on the behaviour of marmosets when confronted with their unfamiliar conspecifics. Effects of anxiolytics in mice were compared with those of quinpirole, given at anxiogenic dose levels. The results showed that during social interaction, anxiolytic compounds released behaviour of animals that normally was suppressed by social and environmental constraints. In male mice, anxiolytics also increased exploratory digging and in some cases enhanced aggression. Quinpirole, however, in these models, decreased their social investigation, non-social activities as well as locomotor activities while increasing their flight behaviour. In the present studies, the light/dark box model was found to be sensitive to chlordiazepoxide and several other anxiolytics after acute administration. Effects of three classical antidepressants (imipramine, phenelzine, mianserin) on social interaction in male mice were also screened, using similar ethological techniques. It was found that the effects of antidepressants following different time courses were different from the effects of anxiolytics. When given acutely, antidepressants induced a range of diverse changes to behaviour which included anxiogenic-like effects, such as decrease of aggressive behaviour and social investigation. After subchronic administration, antidepressants exhibited anxiolytic-like effects in that they increased social investigation and sometimes increased aggression. Enhancement of exploratory digging was found only by subchronic administration of one of the antidepressants tested. Commonalities in the behavioural effects induced by anxiolytics and antidepressants when given by long-term administration indicate that they may be acting at common pathways in the central nervous system. They may act to suppress functioning of the behavioural inhibition system and also influence the hippocampal-5-HT defence reactions. The dissimilarities of behavioural effects produced by anxiolytics and antidepressants suggest that these drugs may alter defensive responding via different neurochemical routes

Not available / text

published_or_final_version / Literary Studies / Master / Master of Arts

published_or_final_version / English Studies and Comparative Literature / Master / Master of Philosophy