Readers will note that an innovation is being introduced in this journal: the inclusion of a short summary at the end of each paper. This has been found to be useful in reading other professional publications and therefore has been adopted for our Journal.

As some of the papers in this issue were received before the change of policy, they do not all have a summary, but in future all contributors will be asked to provide one. The Editorial Board hopes that this will assist our readers, and would welcome feedback on the matter.