Copyright © 2003 IOP Publishing Ltd.

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior permission of the publisher. Multiple copying is permitted in accordance with the terms of licences issued by the Copyright Licensing Agency under the terms of its agreement with Universities UK (UUK). C R Kitchin has asserted his moral rights under the Copyright, Designs and Patents Act 1998 to be identified as the author of this work. British Library Cataloguing-in-Publication Data A catalogue record for this book is available from the British Library