Simulated X-ray Spectra From Ionized Wind-Blown Nebulae around Massive Stars

Using an ionization gasdynamics code, we simulate a model of the wind-blown bubble around a 40 solar mass star. We use this to compute the X-ray spectra from the bubble, which can be directly compared to observations. We outline our methods and techniques for these computations, and contrast them with previous calculations. Our simulated X-ray spectra compare reasonably well with observed spectra of Wolf-Rayet bubbles. They suggest that X-ray nebulae around massive stars may not be easily detectable, consistent with observations.Comment: 7 pages, 2 figures. Revised and shortened version following referee comments. Accepted to High Energy Density Physic

The roles of the formal and informal sectors in the provision of effective science education

For many years, formal school science education has been criticised by students, teachers, parents and employers throughout the world. This article presents an argument that a greater collaboration between the formal and the informal sector could address some of these criticisms. The causes for concern about formal science education are summarised and the major approaches being taken to address them are outlined. The contributions that the informal sector currently makes to science education are identified. It is suggested that the provision of an effective science education entails an enhanced complementarity between the two sectors. Finally, there is a brief discussion of the collaboration and communication still needed if this is to be effective

A comparison of the neutral detergent-cellulase method with other laboratory methods for predicting the digestibility in vivo of maize silages from three European countries

Four populations of maize silage have been studied with the objective of comparing the ability of the neutral detergent-cellulase plus amylase (NCD) procedure with various fibre methods and starch to predict digestible organic matter content in dry matter (DOMD). The four populations comprised 16 samples examined at the ADAS Feed Evaluation Unit (Population F), 16 samples from the Rowett Research Institute (Population R), 50 samples studied at the National Institute of Animal Nutrition, Ghent, Belgium (Population B) and 24 samples from the Research Institute for Livestock Feeding and Nutrition, Lelystad, Netherlands (Population D). The NCD method provided the best relationship with DOMD in vivo. The overall relationship was: DOMD (g kg-1 DM) =235 + 0.650 NCD (g kg-1 DM), R2=64.4%, r.s.d.=25.8. While the NCD-based relationship for Population R had a significantly (P < 0.001) different intercept, overall, the NCD method was considerably superior at predicting DOMD in vivo than all the fibre methods examined and starch content. The reason for the behaviour of Population R cannot be explained but its retention in the overall relationship was shown to have little effect on predicted values