3,724 research outputs found
Smart Cities and Digitized Urban Management
By 2050, two-thirds of the world’s population is expected to reside in cities and urban agglomerations (UN Department of Economic and Social Affairs 2014). Cities have always showcased the best and the worst aspects of humanity – gleaming skyscrapers, art, and inventiveness on the one hand; slums, crime, and abject poverty on the other. Such challenges, which cities already face, will be further amplified by increasing urbanization, and it will be coastal cities in particular that bear the brunt of the global threat of climate change. Not without reason is the quest for “Sustainable Cities and Communities” one of the UN’s explicit sustainable development goals (United Nations 2015)
Probing Wolf-Rayet Winds: Chandra/HETG X-Ray Spectra of WR 6
With a deep Chandra/HETGS exposure of WR 6, we have resolved emission lines
whose profiles show that the X-rays originate from a uniformly expanding
spherical wind of high X-ray-continuum optical depth. The presence of strong
helium-like forbidden lines places the source of X-ray emission at tens to
hundreds of stellar radii from the photosphere. Variability was present in
X-rays and simultaneous optical photometry, but neither were correlated with
the known period of the system or with each other. An enhanced abundance of
sodium revealed nuclear processed material, a quantity related to the
evolutionary state of the star. The characterization of the extent and nature
of the hot plasma in WR 6 will help to pave the way to a more fundamental
theoretical understanding of the winds and evolution of massive stars.Comment: Accepted by the Astrophysical Journa
'The heart of what we do': policies on teaching, learning and assessment in the learning and skills sector
One of the stated aims of government policy in England is to put teaching, training,and learning at the heart of the learning and skills system. This paper provides a critical review of policies on teaching, learning and assessment in the learning and skills sector over the past five years. It draws upon data collected and analysed in the early stages of an ESRC-funded Teaching and Learning Research Programme project. Using evidence from policy sources, we argue that despite policy rhetoric about devolution of responsibility to the 'front line', the dominant 'images' that government has of putting teaching, learning and assessment at the heart of the Learning and Skills Sector involves a narrow concept of learning and skills; an idealisation of learner agency lacking an appreciation of the pivotal role of the learner/tutor relationship and a top-down view of change in which central government agencies are relied on to secure education standards
Assessment of Computational Fluid Dynamics (CFD) Models for Shock Boundary-Layer Interaction
A workshop on the computational fluid dynamics (CFD) prediction of shock boundary-layer interactions (SBLIs) was held at the 48th AIAA Aerospace Sciences Meeting. As part of the workshop numerous CFD analysts submitted solutions to four experimentally measured SBLIs. This paper describes the assessment of the CFD predictions. The assessment includes an uncertainty analysis of the experimental data, the definition of an error metric and the application of that metric to the CFD solutions. The CFD solutions provided very similar levels of error and in general it was difficult to discern clear trends in the data. For the Reynolds Averaged Navier-Stokes methods the choice of turbulence model appeared to be the largest factor in solution accuracy. Large-eddy simulation methods produced error levels similar to RANS methods but provided superior predictions of normal stresses
Assessing the impact of drinking water and sanitation on diarrhoeal disease in low- and middle-income settings: Systematic review and meta-regression
Objective: To assess the impact of inadequate water and sanitation on diarrhoeal disease in low- and middle-income settings. Methods: The search strategy used Cochrane Library, MEDLINE & PubMed, Global Health, Embase and BIOSIS supplemented by screening of reference lists from previously published systematic reviews, to identify studies reporting on interventions examining the effect of drinking water and sanitation improvements in low- and middle-income settings published between 1970 and May 2013. Studies including randomised controlled trials, quasi-randomised trials with control group, observational studies using matching techniques and observational studies with a control group where the intervention was well defined were eligible. Risk of bias was assessed using a modified Ottawa-Newcastle scale. Study results were combined using meta-analysis and meta-regression to derive overall and intervention-specific risk estimates. Results: Of 6819 records identified for drinking water, 61 studies met the inclusion criteria, and of 12 515 records identified for sanitation, 11 studies were included. Overall, improvements in drinking water and sanitation were associated with decreased risks of diarrhoea. Specific improvements, such as the use of water filters, provision of high-quality piped water and sewer connections, were associated with greater reductions in diarrhoea compared with other interventions. Conclusions: The results show that inadequate water and sanitation are associated with considerable risks of diarrhoeal disease and that there are notable differences in illness reduction according to the type of improved water and sanitation implemented
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