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1	Behavioural and brain mechanisms of associative change during blocking and unblocking Bradfield, Laura Anne, Psychology, Faculty of Science, UNSW January 2009 (has links) The present thesis examined the behavioural and brain mechanisms of associative change in the rat during Pavlovian fear conditioning as measured by freezing. The first series of experiments (Chapter 3) used compound test designs to study how learning is distributed among excitatory and neutral conditional stimuli (CSs). More was learned about a neutral CSB than an excitatory CSA when trained in isolation, indicating that fear learning is negatively accelerated. CSA blocked fear learning to CSB when trained in compound. Unblocking of CSB occurred if the AB compound signalled an increase in unconditional stimulus (US) intensity or number. Assessments of associative change during blocking showed that more was learned about CSB than CSA. Such assessments during unblocking revealed that more was learned about CSB than CSA following an increase in US intensity but not US number. These US manipulations had no differential effects on single-cue learning. The results show that variations in US intensity or number produce unblocking of fear learning, but for each there is a different profile of associative change and a potentially different mechanism. The second series of experiments (Chapter 4) demonstrated that these stimulus selection effects are mediated, at least in part, by nucleus accumbens shell (AcbSh). AcbSh lesions augmented overshadowing during compound conditioning and promoted learning about CSA at the expense of CSB during blocking designs. Lesioned rats could learn normally about the novel CSB if it was rendered more informative regarding shock in Stage II. These results identify an important role for AcbSh and ventral striatum in distributing attention and learning among competing predictors of danger. Nucleus accumbens shell Blocking and Unblocking Summed and seperable prediction error
2	On some results of analysis in metric spaces and fuzzy metric spaces Aphane, Maggie 12 1900 (has links) The notion of a fuzzy metric space due to George and Veeramani has many advantages in analysis since many notions and results from classical metric space theory can be extended and generalized to the setting of fuzzy metric spaces, for instance: the notion of completeness, completion of spaces as well as extension of maps. The layout of the dissertation is as follows: Chapter 1 provide the necessary background in the context of metric spaces, while chapter 2 presents some concepts and results from classical metric spaces in the setting of fuzzy metric spaces. In chapter 3 we continue with the study of fuzzy metric spaces, among others we show that: the product of two complete fuzzy metric spaces is also a complete fuzzy metric space. Our main contribution is in chapter 4. We introduce the concept of a standard fuzzy pseudo metric space and present some results on fuzzy metric identification. Furthermore, we discuss some properties of t-nonexpansive maps. / Mathematical Sciences / M. Sc. (Mathematics) Metric space Cauchy sequence Compactness Precompactness Completeness Continuity Uniform continuity Isometry Uniform convergence Seperable Nested Closed sets Diameter Pseudo metric space Fuzzy metric space Standard fuzzy metric space Fuzzy pseudo metric space Metric identification Fuzzy metric identification Nonexpansive map t-nonexpansive map t-uniformly continuous map t-isometry map Quotient map Quotient topology Quotient space Natural map Topological space 514.325 Metric spaces Fuzzy topology
3	On some results of analysis in metric spaces and fuzzy metric spaces Aphane, Maggie 12 1900 (has links) The notion of a fuzzy metric space due to George and Veeramani has many advantages in analysis since many notions and results from classical metric space theory can be extended and generalized to the setting of fuzzy metric spaces, for instance: the notion of completeness, completion of spaces as well as extension of maps. The layout of the dissertation is as follows: Chapter 1 provide the necessary background in the context of metric spaces, while chapter 2 presents some concepts and results from classical metric spaces in the setting of fuzzy metric spaces. In chapter 3 we continue with the study of fuzzy metric spaces, among others we show that: the product of two complete fuzzy metric spaces is also a complete fuzzy metric space. Our main contribution is in chapter 4. We introduce the concept of a standard fuzzy pseudo metric space and present some results on fuzzy metric identification. Furthermore, we discuss some properties of t-nonexpansive maps. / Mathematical Sciences / M. Sc. (Mathematics) Metric space Cauchy sequence Compactness Precompactness Completeness Continuity Uniform continuity Isometry Uniform convergence Seperable Nested Closed sets Diameter Pseudo metric space Fuzzy metric space Standard fuzzy metric space Fuzzy pseudo metric space Metric identification Fuzzy metric identification Nonexpansive map t-nonexpansive map t-uniformly continuous map t-isometry map Quotient map Quotient topology Quotient space Natural map Topological space 514.325 Metric spaces Fuzzy topology

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