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In this thesis we are concerned with the optimal control of jump type Stochastic Differential equations(SDEs), which we utilize to model the incomplete financial market. It is demonstrated how Levy type processes associated to general generators with variable coefficients can be linked to Levy processses with jumps in an abstract setting. Thus providing a useful way to deal with optimization problems where the financial market is being driven by a Levy type process. An application to two portfolio optimization problems will be made, initially set out in the abstract setting. Then with a special interest in modelling with stable-like processes we construct the coefficient of the jump term in the associated jump-type SDE, associated to a polar decomposed Levy measure, we are able to solve these optimization problems concretely.

This thesis examines the extent to which regulation theory provides an appropriate theoretical framework for analysing the development of capitalist economic relations and activities in transitional economies. The investigation uses secondary sources and information gained from interviews conducted with tourism business owners and managers in three Vietnamese cities: Hanoi, Hue and Ho Chi Minh City. I find that through its recognition of firstly, the path dependent nature of regulatory processes and secondly, national and local scales as key sites in the regulation of global economic processes, regulation theory can be utilised in analysing the development of capitalist economic relations and activities in transitional economies. Nevertheless, the findings in this thesis also challenge and offer new perspectives on a number of the key concepts contained within regulation theory. Firstly, my findings illustrate how political imperatives play a much more significant role in the regulation of economic activity than acknowledged in regulation theory. In Vietnam, as a way of maintaining the state as the leading institution in the Vietnamese socioeconomy, the central Vietnamese state has historically ceded a significant degree of regulatory control over economic space to the local state. As a consequence, the local state has traditionally constituted the key institution regulating economic activity in local space. In the transitional Vietnamese economy, I illustrate that political imperatives are continuing to inform the practices of the central state in regulating nascent capitalist economic processes. I find that this is chiefly being articulated through the informal regulatory practices and capacity of the central state as it seeks to mediate capitalist economic relations between supra and sub-national actors and institutions. This runs counter to assertions within regulation theory where the regulatory power of the central state is chiefly derived from its capacity to enact a formal framework of regulatory forms to guide global economic processes throughout national space. Secondly, I highlight the importance of the social regulation of economic activity and how in Vietnam the cultivation of social ties with local state officials has historically constituted an important institutional mechanism regulating economic activity in local spaces. In the transitional Vietnamese economy, I find that among private tourism business owners interviewed in Hanoi, Hue and Ho Chi Minh City, the cultivation of social ties with local state officials has continued to play an important role in the establishment and running of their businesses. Out of these findings, I adapt the conceptual framework provided in regulation theory and build a more appropriate analytical framework that can be utilised in examining how regulatory processes and relations are evolving in regulating capitalist economic activity in transitional economies.

According to a current hypothesis there is a putative stromal stem cell in bone marrow, capable of giving rise to adipogenic, osteogenic, fibroblastic and reticular cell lines. An aim of this thesis was to obtain information about the hierarchy and potential for differentiation of these marrow stromal cell lines in young adult rabbits. Particular objectives were to determine the conditions required for expression of the adipocytic phenotype in vitro/ to obtain cloned populations of adipocytic cells and to compare their potential for differentiation with that of populations derived from marrow fibroblastic colonies using an in vivo diffusion chamber (DC) assay. Adipocytic colonies differentiated and grew to a limited size in medium supplemented with rabbit plasma, but attempts to isolate and expand them in this medium failed. On changing the serum supplement to FCS, adipocytic cells acquired a less differentiated morphology. There was a large increase in colony growth and cells were produced in sufficient numbers for the DC assay. 31 fibroblastic and 21 adipocytic colonies were isolated and expanded. Of these, 11 fibroblastic and 8 adipocytic colonies provided enough cells for implantation in DC's. 4 of the 11 fibroblastic and 3 out of the 8 adipocytic colonies formed bone in the chambers. It was concluded that cells which have differentiated in an adipocytic direction are able to revert to a more proliferative stage and subsequently to differentiate along the osteogenic pathway. Adipocytic and fibroblastic cells cultured in vitro from marrow have, with osteogenic cells, a common precursor in adult marrow. Several phenotype specific differentiation markers have been identified for extra-medullary, but not marrow adipocytes. PAL422(AP2), a P2-like myelin protein is a specific marker expressed during differentiation by a number of extramedullary adipocytic cell lines. A further objective was to determine if PAL422(AP2) is expressed in marrow adipocytic cultures, and to asses its value as a marker of adipocytic differentiation in the marrow stromal system. Using western and northern blot analysis, expression of PAL422(AP2) was demonstrated in rat marrow cell cultures then localized to pre-adipocytes and young adipocytes by immunohistochemistry. Thus, PAL422(AP2) is of value as a differentiation marker of marrow adipocytes.