Arion Ferussac, 1819, is a large, predominantly western Palearctic genus of slugs with a number of species that are of considerable agricultural and forestry concern. Many Arion species have been introduced throughout the world through commerce, and have established themselves as pests in predo- minantly synanthropic and other disturbed environments in the USA and Canada (Robinson, 1999). Since 1999, nation- wide surveys under the umbrella of the USDA North American Slug Project have been conducted to document the current distributions of non-native slug species. Arion species are as yet found to be absent from Puerto Rico, and surveys in Alaska and the Hawaiian Islands are incomplete. In view of the potential threat of new introductions of non- established Arion species, all specimens intercepted from incom- ing shipments from abroad must be identified by quarantine authorities in order to determine whether or not the associated commodity can be allowed to enter the country. Arion slugs are frequently intercepted at the US ports on commercial imports from Europe, particularly associated with shipments of mush- rooms, cut flowers, flower bulbs, horticultural plants and veg- etables. However, most intercepted slugs are immature, lacking the diagnostic genitalia that would facilitate their identifi- cation. Without internal examination, several species are difficult to identify, as the plethora of synonyms in the malaco- logical literature would suggest. The adults of some species resemble the immatures of others, and the external appearance of a species may also differ according to its geographic origin.

Background and purpose. The objective of this study was to assess set-up reproducibility of pelvic treatments for obese patients in the prone position, with and without the use of an immobilisation shell.Method and materials. The patients were treated using a posterior open field and opposed lateral wedged fields for 20 fractions over four weeks. Ten fractions were set-up using a pelvic shell and ten fractions without. The patients were randomised into two groups, whose initial set-up was either with or without a shell. Portal images were obtained on 14 treatment fractions (7 for each set-up) and compared against initial simulator images to assess movement. For each fraction when portal imaging was scheduled the treatment radiographers also assessed the ease at which the patient could be positioned. The aim was to determine the correlation between good visual positioning to surface marks and accurate location of bony landmarks in portal imaging.Results. Early results from this study highlighted large random positioning errors in the superior/inferior plane when patients were positioned in the pelvic shell. The study was therefore abandoned at patient number four.Conclusion. The use of the pelvic shell was found to increase positioning errors in the longitudinal (superior-inferior) direction. Reasons for this observation are discussed and modifications to the shell design suggested. The study also highlighted that ease of patient positioning using surface marks is not a good guide to positional accuracy and emphasises the importance of regular on-set verification.

Background and Purpose: The aim of this study was to determine set-up accuracy when comparing an Orfit® thermoplastic shell to a traditional acetate shell for the treatment of patients with age related macular degeneration.Method and Materials: 20 patients with age related macular degeneration were sequentially allocated to be positioned in either an Orfit® shell or a traditional acetate shell (ten patients in each group). On each day of treatment, radiographic portal imaging was used to ascertain accuracy by comparison with the CT image and verification radiograph.Results: 140 portal images were assessed by three independent readers. Pearson Correlation and ANOVA statistics were performed on the data to assess differences between the two types of shell. Inter- and intraobserver variations were also analysed. Results, for both Orfit® and Acetate, revealed that over 95% of error movements were 2 mm or less.Conclusions: The study indicates that both devices are of comparable accuracy and that the Orfit® shell is an acceptable method of immobilisation for the treatment of age related macular degeneration.

Beta SiC powders with various surface areas were pressureless sintered in the presence of B and C to densities of over 95% TD. The highest density (> 98% TD) was obtained with deagglomerated powders having high surface area and intermediate green density. The as-received, low surface area powders could also be sintered to high density (approximately 95% TD) provided that they had good pressing characteristics. However, larger quantities of particles above approximately 1-mu-m increased the diffusion distances and prevented the attainment of densities above 95% TD.

Des poudres de β-SiC presentant differentes aires superficielles ont ete frittees en presence de B et C jusqu'a des densites de plus de 95% de la valeur theorique. La densite la plus elevee (plus de 98%) a ete obtenue avec des poudres desagglomerees d'aire superficielle elevee et de densite crue intermediaire.

The Abel inversion method of determining the radial profile of the volume emission coefficient in cylindrically symmetric sources is extended through an iteration technique to apply to sources which are not optically thin. An experiment is described in which this technique is applied to a low temperature plasma, and the radial profile of the volume emission and absorption coefficients are obtained. The ratios of these two profiles are used to obtain the temperature profile of the plasma using Kirchhoff’s law under the assumption of local thermodynamic equilibrium.