The objective of this thesis is to analyze three key aspects of the long-term relationship between energy policy and overall economic policy in Mexico: (1) energy- industrialization; (2) energy-labour force; and (3) energy-foreign debt.
The importance of the energy sectors in the general economy is evaluated from a historical perspective. Some of the most representative energy studies, both theoretical and empirical are reviewed. Also, the structure and specification of some general equilibrium (GE) models constructed for Mexico are compared within a SAM-type conceptual framework. The SAM approach is then used to formulate the one-period version of the model.
An optimizing intertemporal GE model is constructed and implemented to analyze the interdependence between the decisions of the various economic agents, and to explore the sensitivity of optimal policies with respect to such key parameters as elasticities of substitution and world oil prices. The starting point of the model is the work by Blitzer and Eckaus (1986a).
However, given the different nature of the present study, five types of improvements have been introduced: (i) the objective function and the terminal constraints are formulated in a way that leads to more attractive price structures; (ii) the model contains truly price-sensitive endogenous choices; (iii) there is a greater degree of disaggregation of the accounts; (iv) the data base is more updated; and (v) a much improved software is employed for solving the model.
The following are some of the main conclusions derived from the various solutions of the model:
- Both the real and dual sides of the model capture a structural adjustment process towards expansion of nonoil tradeable producing sectors. Manufacturing exports replace oil and gas revenues and external capital inflows as the main source of foreign currency.
- Foreign exchange is the most serious constraint of the system, so that foreign debt reduction is considered as the most profitable way of allocating current income.
- This calls for a portfolio switching effect among the assets that constitute Mexico's wealth: foreign debt reduction affects investment in real capital assets, which, in turn, means that the economy grows below the labour force growth. Moreover, in the majority of the experiments, oil and gas extraction levels are constrained by the ceilings imposed by the government.
- Skilled labour force shortages also restrict the economy significantly. Yet, the economy is not constrained in its ability to absorb oil revenues.
The necessity for vitamin B12 in animals and the consequences of lack of it are well-documented in the literature. Its unique and indispensable role, and its active form as the coenzyme for at least eleven different enzymic rearrangements in vivo, are also known. The enzymic conversion of a-MG to MelT, which is the centre of interest in the present work, is one of these rearrangements. However, the mechanism by which most of these rearrangements proceed is still a matter of speculation, based on logic and inconclusive experimental observations. Organocobalt model systems, which resulted from the suggestion that substrate-Co species are intermediates in these rearrangements, have been synthesised and studied in their thousands by various workers, and have in some instances shed light on this intriguing mechanistic problem. This thesis is a description of the synthesis, characterisation and rearrangement of monocarboxylate-substituted but-3-enyl- and cyclopropylmethyl(pyridine)- cobaloximes, in a model study of the B^2-dePendent enzymic rearrangement of a-MG. The syntheses of the alkylating agents are described, and novel compounds, which are fully characterised, are reported. The findings from this study suggest that alkyl-cobalamins postulated as intermediates in the reaction catalysed by a-MG mutase would be insufficiently reactive towards rearrangement. However, rapidly interconverting carboxy-substituted but-3-enyl and cyclopropylmethyl radicals are suggested to be plausible intermediates. An addenda to this thesis contains synthetic proposals for the continuation of this work. A separate chapter (Chapter 5) describes the preparation and testing of the cyclic analogues of the antitumour drug busulphan, viz., oia— and trans-di(hydroxymethyUcyclopropane dimethanesulphonate. Both compounds showed little antitumour activity near their toxic dose. The implications of these observations for the mode of action of busulphan are discussed.
This thesis describes various applications of high field n.m.r. for the elucidation of coal structure, and concentrates on discovering the chemical environments of the heteroatoms in coal i.e. those elements other than carbon and hydrogen.
Chapter 2 describes how hydroxyl groups may be converted to trimethyl siloxyl groups, observation of which by 29si n.m.r. allows one to determine the types of hydroxyl functionalities present in the original material. Such derivatization methods are well known. However trimethyl siloxyl groups give 29si resonances that have predictable chemical shifts and so the derivative spectra of complex coal tars and extracts are easy to interpret. Using this technique we have investigated the nature of hydroxyl groups in a rank series of coal tars. This has given us some insight into the way the hydroxyls are affected by coalification.
Chapter 3 is a demonstration of the use of n.m.r. as a detector for H.P.L.C.. This has two principle novelties over previous work. Firstly it does not involve building a special probe and secondly, the data is presented as a contour plot of intensity vs. retention time and chemical shift. This method has been used to investigate the nature of several tar fractions and complements the derivatization technique of chapter 2.
The final chapter shows how the nature of sodium in coal was determined by 23Na MAS-NMR. By using the information contained in the chemical shift and linewidths of raw and dried coal it was concluded that sodium exists bound to the surface of coal pores by oxygen functions such as carboxylates and phenoxides. It does not exist as sodium chloride microcrystals as once thought.