Star formation bursts in isolated spiral galaxies

We study the response of the gaseous component of a galactic disc to the time dependent potential generated by N-body simulations of a spiral galaxy. The results show significant variation of the spiral structure of the gas which might be expected to result in significant fluctuations in the Star Formation Rate (SFR). Pronounced local variations of the SFR are anticipated in all cases. Bursty histories for the global SFR, however, require that the mean surface density is much less (around an order of magnitude less) than the putative threshold for star formation. We thus suggest that bursty star formation histories, normally attributed to mergers and/or tidal interactions, may be a normal pattern for gas poor isolated spiral galaxies.Comment: 7 pages, 7 figures To be published in Monthly Notices Roy. Astr. So

The measurement of health-related quality of life (QOL) in paediatric clinical trials: a systematic review

Background The goal of much care in chronic childhood illness is to improve quality of life (QOL). However, surveys suggest QOL measures are not routinely included. In addition, there is little consensus about the quality of many QOL measures. Objectives To determine the extent to which quality of life (QOL) measures are used in paediatric clinical trials and evaluate the quality of measures used. Design Systematic literature review. Review Methods Included paediatric trials published in English between 1994 and 2003 involving children and adolescents up to the age of 20 years, and use of a standardised QOL measure. Data Sources included MEDLINE, CINAHL, EMB Reviews, AMED, BNI, PSYCHINFO, the Cochrane library, Internet, and reference lists from review articles. Results We identified 18 trials including assessment of QOL (4 Asthma, 4 Rhinitis, 2 Dermatitis, and single studies of Eczema, Cystic fibrosis, Otis media, Amblyopia, Diabetes, Obesity associated with a brain tumour, Idiopathic short stature, and Congenital agranulocytosis). In three trials, parents rated their own QOL but not their child's. Fourteen different QOL measures were used but only two fulfilled our minimal defined criteria for quality. Conclusions This review confirms previous reports of limited use of QOL measures in paediatric clinical trials. Our review provides information about availability and quality of measures which will be of especial value to trial developers

Assessing and benchmarking the performance of advanced building facades

This chapter describes the energy demand reshaping and supply technologies that may be encapsulated within an advanced building façade - for example, transparent and breathable insulation, advanced glazing, daylight capture, photovoltaic components and ducted wind turbines. Laboratory testing techniques for the characterisation of the fundamental parameters underlying each technology are elaborated as the essential prerequisite of integrated performance appraisals of specific technology combinations within an advanced façade design context. Based on the results from simulations undertaken in the UK climate context, performance benchmarks are suggested for some principal façade configurations