Search

The purpose of this study is to calculate Pareto surfaces in multi-criteria radiation treatment planning and to analyse the dependency of the Pareto surfaces on the objective functions used for the volumes of interest. We develop a linear approach that allows us to calculate truly Pareto optimal treatment plans, and we apply it to explore the tradeoff between tumour dose homogeneity and critical structure sparing. We show that for two phantom and two clinical cases, a smooth (as opposed to kinked) Pareto tradeoff curve exists. We find that in the paraspinal cases the Pareto surface is invariant to the response function used on the spinal cord: whether the mean cord dose or the maximum cord dose is used, the Pareto plan database is similar. This is not true for the lung studies, where the choice of objective function on the healthy lung tissue influences the resulting Pareto surface greatly. We conclude that in the special case when the tumour wraps around the organ at risk, e.g. prostate cases and paraspinal cases, the Pareto surface will be largely invariant to the objective function used to model the organ at risk.

Drawing on the painting, constructions and writing of the British artist Peter Lanyon, we explore how geographical knowledge is represented in modern abstract art. Lanyon had a deeply felt sense of Cornish identity and attachment to the history, people and place of West Cornwall. He also adopted particular practices - such as gliding - in which he experimented with bodily position and experience. We examine how these practices and cultural identity flowed together, constituting a kind of knowledge which was transposed into his art, the making of which was also an integral part of this dynamic process. We conclude that Lanyon’s perspective departs from the surveying gaze of traditional landscape representation, and also from the autonomous aesthetic common to abstract expressionists. Lanyon’s historical and cultural conception of landscape, as well as his spatial practices, suggest an awareness of landscape as socially defined. So, in a wider sense, we regard Lanyon’s geographical knowledge as a distinctive exploration of the relationship between individual, society and space.

Superconducting melt-textured bulk (RE)BCO large grain materials are one of the most promising materials for power applications of high temperature superconductivity at the liquid nitrogen temperature range. Industrial applications are expected in high-speed low-loss magnetic bearings for flywheel energy storage devices, high-dynamic high-torque electric reluctance motors, and MAGLEV transportation systems. The material has high magnetic field trapping capability and therefore a new class of high-field superconducting permanent magnets will soon appear. However, there is still the need to improve the magnetic and mechanical material properties, as well as to increase the single domain size.This special issue contains papers concerning these topics presented at the International Workshop on the Processing and Applications of Superconducting (RE)BCO Large Grain Materials. The workshop was held on the 30 June-2 July 2003 in Jena, Germany, and was organized by the Institut fuer Physikalische Hochtechnologie, Jena. It was the fourth in the series of PASREG workshops after Cambridge, UK (1997), Morioka, Japan (1999), and Seattle, USA (2001). Sixty two contributions were presented at the workshop, 38 oral presentations and 24 poster presentations. This special issue contains 42 papers.The editors are grateful for the support of many colleagues who reviewed the manuscripts to guarantee their high technical quality. The editors also wish to thank Doris Litzkendorf and Tobias Habisreuther from Institut fuer Physikalische Hochtechnologie, Jena, for their assistance with the organization and handling of the manuscripts. Many thanks to the workshop co-chairman Gernot Krabbes from Leibniz-Institut fuer Festkoerper und Werkstoffforschung, Dresden, for hosting the workshop participants in Dresden. Finally, all attendees wish to acknowledge the efforts of Wolfgang Gawalek, Tobias Habisreuther, Doris Litzkendorf and the Team of Department Magnetics from the Institut fuer Physikalische Hochtechnologie, Jena, for being generous hosts during the workshop.The International PASREG Board selected the following distinguished researchers as recipients of the 2003 PASREG Award for Excellence to acknowledge their contribution to the development of bulk high-temperature superconductors: Masato Murakami, ISTEC Tokyo; Günter Fuchs, IFW Dresden; Uichiro Mitzutani, Nagoya University; Bernhard Oswald, OSWALD Electric Motors Co. Miltenberg; Anna E Carillo, Teresa Puig and Xavier Obradors, ICMAB Barcelona.