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Knowledge of energy deposition in biological cells at nanometer dimensions is essential to understand the biological effects of radiation. This work has resulted in the development of a practical tool to study such energy deposition experimentally, at nanometer dimensions. The main contribution of this research is the design of a cylindrical wall-less proportional counter of 1mm height by 1mm diameter. A wall-less detector (also called grid-walled detector) overcomes the so-called “wall effect”, an experimental artifact that introduces distortions in the radiation energy measurements. An important feature of this detector that distinguishes it from other detectors is its modular design. This allows the detector to be repaired or modified, when necessary, without having to completely disassemble it. Novel design techniques were adopted resulting in a functional detector that can simulate cellular sites as small as 10 nanometers, approximately the size of many molecules in the cell. The detector was tested with a 1 microcurie sealed Am-241 source, which primarily emits monoenergetic alpha particles of energy 5.57 MeV. Microdosimetric spectra analysis for alpha particles and its delta rays from Am-241 were performed for simulated site sizes ranging from 500nm to 10nm. Initial studies to validate the detector design have confirmed good detector performance. We believe this work will serve as a vital platform for bridging the experimentally measured energy spectra to the biological effects of alpha and delta radiations.

Knowledge of energy deposition in biological cells at nanometer dimensions is essential to understand the biological effects of radiation. This work has resulted in the development of a practical tool to study such energy deposition experimentally, at nanometer dimensions. The main contribution of this research is the design of a cylindrical wall-less proportional counter of 1mm height by 1mm diameter. A wall-less detector (also called grid-walled detector) overcomes the so-called “wall effect”, an experimental artifact that introduces distortions in the radiation energy measurements. An important feature of this detector that distinguishes it from other detectors is its modular design. This allows the detector to be repaired or modified, when necessary, without having to completely disassemble it. Novel design techniques were adopted resulting in a functional detector that can simulate cellular sites as small as 10 nanometers, approximately the size of many molecules in the cell. The detector was tested with a 1 microcurie sealed Am-241 source, which primarily emits monoenergetic alpha particles of energy 5.57 MeV. Microdosimetric spectra analysis for alpha particles and its delta rays from Am-241 were performed for simulated site sizes ranging from 500nm to 10nm. Initial studies to validate the detector design have confirmed good detector performance. We believe this work will serve as a vital platform for bridging the experimentally measured energy spectra to the biological effects of alpha and delta radiations.

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No description available.

No description available.

No description available.

The primary purpose of the dissertation is to establish a conceptual study that will assist in financial policy formulation, and further applied research on banking institutions in LDCs and in Nigeria in particular. In order to achieve this, we examined existing models of banks' portfolio behaviour with a view to isolating major issues that should be the concern of policy; the pecularities of banking operations in LDCs were also examined and analysed. Having done these we then settled for two adaptable models capable of providing insights into the problem of commercial banks' portfolio behaviour in Nigeria. The choice of models was made in the light of the data constraint faced in the study. The two complementary models, the first a static model and the other a dynamic model have their basis in utility maximization. They both gave rise to multivariate analysis in empirical implementation. The summary of results with policy implications concern: (i) the relative insignificance of the interest rate variables and their relative inelasticities, particularly with respect to bank loans and other medium term bank portfolios; (ii) availability of funds were more significant on banks portfolio allocation of funds than other variables, particularly those measuring the cost of funds; (iii) on other policy variables, reserve policies of the financial authority were important in bank portfolio, whereas public sector borrowing from the banks were less important; (iv) the term transformation implied by the portfolio of the banks was shown to be less positive than the underlying structure of funds would imply; (v) the introduction of money market instruments were shown to have affected the adjustment behaviour of the banks; and (vi) the results also held implication for the control of money supply. However, we believe the major contribution of this study to knowledge lies in indicating the responses and lags of banks' behaviour to changes in policy instruments in a developing country like Nigeria. This information would no doubt form the basis for further research.

The thesis presented here analyzes the role of the less developed countries in the environmental issues in the United Nations, evaluates their influence, and analyzes the determinants of this influence. Our study assumes certain goal orientations of spokesmen for the less developed countries. These goal orientations are derived from the underdeveloped condition of most of these countries and their continuing political and economic dependence. They attempt to reduce this dependence through demands for radical transformations in the international political economy. This is done through negotiations with spokesmen for the developed countries. The attainment of their objectives constitutes an exercise of influence over their counterparts from the developed countries. The outcomes themselves, for our study, are less important than the interactions, styles,and conversion of political resources into influence. Therefore, it is on the dynamics of the North-South set of international relations that this study focuses. \~ile the environmental negotiations confirm the persistence of a certain stable pattern of demands on the part of the less developed countries, behavioral discontinuities,in terms of methods or style of negotiation, are evident in a review of the negotiations. Spokesmen for the less developed countries seemed to prefer negotiated settlements to majority voting, which is a significant departure from their past negotiating style. Bloc politics, therefore, need not always be incompatible with negotiations. Spokesmen for most of the developed countries were also unusually more accommodating in their responses to the demands of the less developed countries. The dispositions and interests of the former, the latter's preference for bargaining over majority voting, as well as the transnational character of most of the environmental issues, partly made possible the unusual negotiating behavior of both groups of countries. Another significant finding is that the less developed countries (the weak} have some influance on the developed countries (the strong} in negotiations. The determinants of this influence must be sought in factors other than economic, military, scientific-technological, and communication capabilities on the one hand, or majority voting on the other. This corroborates Professor Zartman's suggestion that the role of power must be analyzed in the context of negotiations. Finally, the study presented here indicates that the concept of environmental quality is broader and more complex than the desire to prevent planetary collapse. There is more to be learn~d about environmental politics in the UN than can be gathered from popular literature. Scientists and advocates of environmental control tend to treat the world globally and ignore essential political differences. As much as the durability of planet Earth is being challenged by the ecological issues, a scientific solution which is divorced from the political context of the issues is not likely to be a realistic response to the pressures in the contemporary international political system. The success of the UN environmental program substantially depends on the attitudes and policies of the developed countries. Unless they are prepared to assume additional moral, economic, and financial responsibilities for making the simultaneous pursuit of development and environmental protection goals possible in the less developed parts of the world, a lingering disagreement is more likely to characterize North-South dialogue on the environment. / Thesis / Doctor of Philosophy (PhD)