Child development and the aims of road safety education

Pedestrian accidents are one of the most prominent causes of premature injury, handicap and death in the modern world. In children, the problem is so severe that pedestrian accidents are widely regarded as the most serious of all health risks facing children in developed countries. Not surprisingly, educational measures have long been advocated as a means of teaching children how to cope with traffic and substantial resources have been devoted to their development and provision. Unfortunately, there seems to be a widespread view at the present time that education has not achieved as much as had been hoped and that there may even be quite strict limits to what can be achieved through education. This would, of course, shift the emphasis away from education altogether towards engineering or urban planning measures aimed at creating an intrinsically safer environment in which the need for education might be reduced or even eliminated. However, whilst engineering measures undoubtedly have a major role to play in the effort to reduce accidents, this outlook is both overly optimistic about the benefits of engineering and overly pessimistic about the limitations of education. At the same time, a fresh analysis is clearly required both of the aims and methods of contemporary road safety education. The present report is designed to provide such an analysis and to establish a framework within which further debate and research can take place

Series impedance of distribution cables with sector-shaped conductors

Models of power distribution networks require accurate cable impedance data. For unbalanced networks, both the self-impedances and the mutual impedances are needed. However, published studies use differing approaches to determine cable impedances, leaving uncertainty over the level of detail required. This paper compares impedances provided by the manufacturer with those from several analytical methods, showing the impact of modelling the non-circular geometry and of including corrections allowing for the AC resistance. The analysis is compared to results from a freely available finite element solver where the current distribution is modelled in detail, taking account of eddy currents and the rotation of the cores relative to the neutral due to the cable lay. At 50 Hz, the analytical methods provide a good approximation but the finite element results show that eddy currents affect the impedance at harmonic frequencies. The results also show the impact of including the ground path in the impedance calculation. The current distribution in the ground has a wide cross-sectional area, suggesting that the assumption of a perfect multi-grounded neutral is inappropriate for LV networks with short cable lengths

Assumptions and approximations typically applied in modelling LV networks with high penetrations of low carbon technologies

Uncertainties in the assessment of LV network capacity to accommodate PV and other low-carbon technologies can lead to installation constraints or costly network reinforcements that may not be entirely necessary. This paper reviews the numerous assumptions often used in such assessments and highlights those relating to time resolution of demand models, harmonics, network grounding and impedance modelling as being particularly questionable. In many cases, the individual assumptions may be low risk, but there is greater uncertainty when assumptions are applied in combination

Impacts of demand data time resolution on estimates of distribution system energy losses

Copper losses in low voltage distribution circuits are a significant proportion of total energy losses and contribute to higher customer costs and carbon emissions. These losses can be evaluated using network models with customer demand data. This paper considers the under-estimation of copper losses when the spiky characteristics of real customer demands are smoothed by arithmetic mean averaging. This is investigated through simulation and by analysis of measured data. The mean losses in cables and equipment supplying a single dwelling estimated from half-hourly data were found to have significant errors of 40%, compared to calculations using high resolution data. Similar errors were found in estimates of peak thermal loading over a half-hour period, with significant variation between results for each customer. The errors reduce as the demand is aggregated, with mean losses for a group of 22 dwellings under-estimated by 7% using half-hourly data. This paper investigates the relationship between the demand data time resolution and errors in the estimated losses. Recommendations are then provided for the time resolution to be used in future measurements and simulation studies. A linear extrapolation technique is also presented whereby errors due to the use of averaged demand data can be reduced

Spectrum of turbulent Kelvin-waves cascade in superfluid helium

To explain the observed decay of superfluid turbulence at very low temperature, it has been proposed that a cascade of Kelvin waves (analogous to the classical Kolmogorov cascade) transfers kinetic energy to length scales which are small enough that sound can be radiated away. We report results of numerical simulations of the interaction of quantized vortex filaments. We observe the development of the Kelvin-waves cascade, and compute the statistics of the curvature, the amplitude spectrum (which we compare with competing theories) and the fractal dimension.Comment: 32 pages, 22 figure

Effects of Housing First approaches on health and wellbeing of adults who are homeless or at risk of homelessness: systematic review and meta-analysis of randomised controlled trials

Background: Homelessness is associated with poor health. A policy approach aiming to end homelessness across Europe and North America, the ‘Housing First’ (HF) model, provides rapid housing, not conditional on abstinence from substance use. We aimed to systematically review the evidence from randomised controlled trials for the effects of HF on health and well-being. Methods: We searched seven databases for randomised controlled trials of interventions providing rapid access to non-abstinence-contingent, permanent housing. We extracted data on the following outcomes: mental health; self-reported health and quality of life; substance use; non-routine use of healthcare services; housing stability. We assessed risk of bias and calculated standardised effect sizes. Results: We included four studies, all with ‘high’ risk of bias. The impact of HF on most short-term health outcomes was imprecisely estimated, with varying effect directions. No clear difference in substance use was seen. Intervention groups experienced fewer emergency department visits (incidence rate ratio (IRR)=0.63; 95% CI 0.48 to 0.82), fewer hospitalisations (IRR=0.76; 95% CI 0.70 to 0.83) and less time spent hospitalised (standardised mean difference (SMD)=−0.14; 95% CI −0.41 to 0.14) than control groups. In all studies intervention participants spent more days housed (SMD=1.24; 95% CI 0.86 to 1.62) and were more likely to be housed at 18–24 months (risk ratio=2.46; 95% CI 1.58 to 3.84). Conclusion: HF approaches successfully improve housing stability and may improve some aspects of health. Implementation of HF would likely reduce homelessness and non-routine health service use without an increase in problematic substance use. Impacts on long-term health outcomes require further investigation. Trial registration number: CRD42017064457

Mass spectrometric identification of intermediates in the O2-driven [4Fe-4S] to [2Fe-2S] cluster conversion in FNR

The iron-sulfur cluster containing protein FNR is the master regulator for the switch between anaerobic and aerobic respiration in Escherichia coli and many other bacteria. The [4Fe-4S] cluster functions as the sensory module, undergoing reaction with O2 that leads to conversion to a [2Fe-2S] form with loss of high affinity DNA-binding. Here we report studies of the FNR cluster conversion reaction using time-resolved electrospray ionization mass spectrometry. The data provide new insight into the reaction, permitting the detection of cluster conversion intermediates and products, including a novel [3Fe-3S] cluster and persulfide coordinated [2Fe-2S] clusters ([2Fe-2S](S)n, where n = 1 or 2). Analysis of kinetic data revealed a branched mechanism in which cluster sulfide oxidation occurs in parallel with cluster conversion, and not as a subsequent, secondary reaction, to generate ([2Fe-2S](S)n species. This methodology shows great potential for broad application to studies of protein cofactorsmall molecule interactions

Methodological considerations of the project management of a hospital project within a practice order network

Practice theory offers numerous theoretical affordances, especially to practitioners and researchers of project management who seek alternatives to the problematic assumed universality of 'traditional' theoretical perspectives. However there is several disagreements left unresolved in practice theory methodology that risk compromising its full potential. Illustrated by an on going, praxiographic study of the practice of project management of a major UK National Health Service (NHS) hospital project, Schatzki's notion of site ontology is drawn upon to implement a research strategy that contributes to resolving such disagreements. It is argued that whilst practice theory methodology ought to be ontologically coherent and contextually driven and, therefore, shaped by the research questions and aims, it is also important to constantly reflect dialogically on the relationship between the particular practice theory used and the phenomena being observed. In addition to adding to the extant literature on the conceptualisation of project management as a practice the study's primary contribution is to identify and examine some of the methodological implications to those who want to use a practice theory approach in consideration of the resolution of its contested methodology

Beyond scoring: facilitating enhanced evaluation of the design quality of NHS healthcare buildings

The evaluation of design quality using prescribed instruments, as now mandated by the UK National Health Service (NHS), provides a research opportunity to acquire understanding of the social interaction of the project stakeholder groups when they are engaged in design evaluation activities. This paper argues that there is a pressing need for such a study, as without it, such evaluations may be unnecessarily limited. This paper argues for a fresh and pluralistic approach to be applied to the evaluation of the design quality of NHS healthcare facilities which complements the methods currently used which are enshrined within prescribed instruments. The new approach uses an interpretative research paradigm to understand the social interactions of the project stakeholders whilst they use the prescribed instruments. The decision to adopt such a pluralistic approach is discussed. The users of this work may include those who seek to improve the design quality of NHS healthcare buildings