Declaration

I hereby declare that the contents of this dissertation are original and have not been submitted in whole or in part for consideration for any other degree or qualification in this, or any other University. This dissertation is the result of my own work and includes nothing which is the outcome of work done in collaboration, except where specifically indicated in the text. This disser-tation contains less than 65,000 words including appendices, bibliography, footnotes, tables and equations and has less than 150 figures.