The Basin and Range province of western North America is a broad region of irregular topographic expression characterized by various styles of Cenozoic extension. Recent reprocessing and interpretation of a regional suite of industry seismic reflection profiles in southern Arizona, in the southern Basin and Range province of southwestern North America, have illuminated subsurface features related to Cenozoic crustal extension and show a detailed view of extensional processes in the southern Basin and Range. Seismic stratigraphic investigations on these profiles suggest a two-phase model for the evolution of the Catalina-Rincon metamorphic core complex, with an initial stage of isostatic core complex emplacement during detachment faulting that resulted in little topographic expression. This was followed, after a significant tectonic hiatus, by late-stage exhumation and flexural uplift of the metamorphic core complex controlled by younger high-angle faulting. Along-strike, upper-plate deformation in response to core complex emplacement was accommodated by the Santa Rita fault, south of the Catalina-Rincon metamorphic core complex. Finite-element models predicts early mechanical failure of the upper-plate of the detachment system to the south of the Catalina core complex. These models suggest that the Santa Rita fault is the result of a perturbation in the regional stress field caused by the Catalina detachment and the associated brittle failure of the upper plate from the extreme crustal extension associated with core-complex emplacement. These profiles, coupled with geologic and well control, indicate that the southwest-dipping Catalina detachment, the northwest-dipping Santa Rita fault, the east dipping Altar Valley fault, and the highly dissected Sierrita Mountains are all aspects of the same extensional event in the middle-Tertiary. These features all appear to merge into a broad zone of middle-crustal deformation and likely represent heterogeneous upper-crustal deformation in response to middle-to-lower crustal homogeneous deformation.

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The binary complexes comprising the molecules hydrogen fluoride, hydrogen chloride, water, hydrogen sulphide, ammonia, phosphine, methane and silane have been studied by ab initio molecular orbital theory thus generating a matrix of eight by eight molecular complexes. The structures, energetics and vibrational spectra of these molecular complexes, both homodimers and heterodimers, have been studied at the second order level of Møller-Plesset perturbation theory using the 6-31G** basis set, by means of the Gaussian 92 computer program. The self consistent field interaction energies have been further dissected into their various components according to the Morokuma scheme, using the Monstergauss computer program. An analysis of the computed interaction energies of the complexes has also been carried out. A complete normal mode analysis, identifying the normal modes of Vibration, has been carried out using the Vibra program. The infrared spectra of some of the associated species have also been determined experimentally by means of the matrix isolation technique using argon and nitrogen as matrix gases. The combined use of the theoretical and experimental approaches has enabled reliable vibrational assignments to be made, which have been used in determining the molecular structures of the aggregates formed on complexation. / Thesis (Ph.D.)-University of Natal, Durban, 1999.

In classical conditioning the amygdala is a critical area for the convergence of the unconditioned (US) and conditioned stimulus (CS). During this process the CS acquires some of the properties of the US. By assessing the US properties of foot-shock, namely reflex, pain and fear, the neural systems of pain and fear were evaluated in the rat basolateral and central amygdala. The central fear state produced by footshock was compared to the central fear state expressed during the fear-potentiated startle paradigm. By analysing the similarities and differences in the fear states, the effects of GABAergic, glutamatergic, and dopaminergic systems and protein synthesis inhibition on these fear states were investigated. The basolateral amygdala was sensitive to GABAergic modulation during US and CS presentations. This was interpreted as a central fear effect. The central amygdala was sensitive to glutamate but not to GABAergic modulation. NMDA receptor antagonism prevented fear arousal to US but not CS presentation. This effect was interpreted as a deficit in pain processing. Non-NMDA receptor antagonism could significantly attenuate both US and CS fear expression. This was interpreted as an overall non-NMDA receptor inhibitory effect that affected pain and conditioned fear expression. Results of these experiments have implications for our understanding of the circuitry involved in processing the US. The basolateral amygdala appears to support emotional neural plasticity while the central amygdala appears to support pain neural plasticity. Finally and and most importantly each area processes different properties of the US.

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It is well known that, as a consequence of the Identity Theorem, we cannot "glue" together two analytic functions to create a new globally analytic function. In this paper we will both introduce and investigate special homeomorphisms, called quasiconformal maps, that are generalizations of the well known conformal maps. We will show that quasiconformal maps make this "gluing," up to conjugation, possible. Quasiconformal maps are a valuable tool in the field of complex dynamics. We will see how quasiconformal maps of infinitesimal circles have an image of an infinitesimal ellipse. Although quasiconformal maps are nice homeomorphisms, they might only be differentiable in the real sense almost everywhere and, surprisingly, complex differentiable nowhere. We shall rely on the work of Lehto and Virtanen as well as Shishikura in exploring these interesting complex valued functions. / Department of Mathematical Sciences