Solar Coronal Structures and Stray Light in TRACE

Using the 2004 Venus transit of the Sun to constrain a semi-empirical point-spread function for the TRACE EUV solar telescope, we have measured the effect of stray light in that telescope. We find that 43% of 171A EUV light that enters TRACE is scattered, either through diffraction off the entrance filter grid or through other nonspecular effects. We carry this result forward, via known-PSF deconvolution of TRACE images, to identify its effect on analysis of TRACE data. Known-PSF deconvolution by this derived PSF greatly reduces the effect of visible haze in the TRACE 171A images, enhances bright features, and reveals that the smooth background component of the corona is considerably less bright (and hence much more rarefied) than commonly supposed. Deconvolution reveals that some prior conlclusions about the Sun appear to have been based on stray light in the images. In particular, the diffuse background "quiet corona" becomes consistent with hydrostatic support of the coronal plasma; feature contrast is greatly increased, possibly affecting derived parameters such as the form of the coronal heating function; and essentially all existing differential emission measure studies of small features appear to be affected by contamination from nearby features. We speculate on further implications of stray light for interpretation of EUV images from TRACE and similar instruments, and advocate deconvolution as a standard tool for image analysis with future instruments such as SDO/AIA.Comment: Accepted by APJ; v2 reformatted to single-column format for online readabilit

Foetal distress - is the paediatrician necessary?

No Abstrac

The incidence and significance of clinical foetal distress in labour

No Abstract

Is stimulation of leaf photosynthesis by elevated carbon dioxide concentration maintained in the long term? A test with Lolium perenne grown for 10 years at two nitrogen fertilization levels under Free Air CO2 Enrichment (FACE)

Photosynthesis is commonly stimulated in grasslands with experimental increases in atmospheric CO2 concentration ([CO2]), a physiological response that could significantly alter the future carbon cycle if it persists in the long term.. Yet an acclimation of photosynthetic capacity suggested by theoretical models and short-term experiments could completely remove this effect of CO2. Perennial ryegrass (Lolium perenne L. cv. Bastion) was grown under an elevated [CO2] of 600 mumol mol(-1) for 10 years using Free Air CO2 Enrichment (FACE), with two contrasting nitrogen levels and abrupt changes in the source: sink ratio following periodic harvests. More than 3000 measurements characterized the response of leaf photosynthesis and stomatal conductance to elevated [CO2] across each growing season for the duration of the experiment. Over the 10 years as a whole, growth at elevated [CO2] resulted in a 43% higher rate of light-saturated leaf photosynthesis and a 36% increase in daily integral of leaf CO2 uptake. Photosynthetic stimulation was maintained despite a 30% decrease in stomatal conductance and significant decreases in both the apparent, maximum carboxylation velocity (V-c,V-max) and the maximum rate of electron transport (J(max)). Immediately prior to the periodic (every 4-8 weeks) cuts of the L. perenne stands, V-c,V-max and J(max), were significantly lower in elevated than in ambient [CO2] in the low-nitrogen treatment. This difference was smaller after the cut, suggesting a dependence upon the balance between the sources and sinks for carbon. In contrast with theoretical expectations and the results of shorter duration experiments, the present results provide no significant change in photosynthetic stimulation across a 10-year period, nor greater acclimation in V-c,V-max and J(max) in the later years in either nitrogen treatment

Optimal Design Approach of Solar Powered Rural Water Distribution Systems in Developing Countries

This is the author accepted manuscript.In many rural parts of the developing world reliable access to clean water and electrical power is constrained. In this study, methods of integrating estimations of power outputs from solar photovoltaic arrays into gravity-fed water distribution network modelling are investigated. The effects of powering a rural water distribution system that is replenished with groundwater pumps that use solar power, and the effect of this on other network design decisions, are investigated. A rural community of an estimated 2,800 people with 28 standpipes from a borehole was chosen to develop the optimisations. The water storage tank and pipework were the focus on the water distribution system. EPANET and generic algorithms were used to run network optimisation simulations of: water tank location, elevation and volume; pipe diameter and configuration; and optimal system design in terms of cost. Different scenarios were included producing supply, demand and required water storage curves, which could have practical application for rural water distribution system design. Indicative costs for theoretical water distribution networks for rural communities in The Gambia were generated

Writing Social Determinants Into and Out of Cancer Control: An Assessment of Policy Practice’

A large literature concurs that social determinants of health are demonstrable, important, and insufficiently attended to in policy and practice. A resulting priority for research should be to determine how the social determinants of health can best be addressed. The authors aim to use this paper to support more effective transfer of social determinants research into policy by: (1) describing a qualitative analysis of thirty-two cancer control policy documents from six OECD countries and two transnational organizations, demonstrating great variability in the treatment of social determinants in these policies (2) critiquing these various policy practices in relation to their likely impact on social determinants of health, and (3) advancing a tool that policy writers can use to assess the way in which social determinants of health have been addressed in their work. In the sample of policy documents, the distinction between structural and intermediate determinants, population-based and targeted interventions, and their respective relationships to equity were not always clear. The authors identified four approaches to social determinants (acknowledging SDH, auditing SDH, stating aims regarding SDH and setting out actions on SDH), and five ways of writing about the relationship between social determinants and cancer risk. These five discourses implied, respectively: that group membership was intrinsically risky; that not enough was known about SDH; that risk arose from choices made by individuals; that groups were constrained by circumstance; or that structural change was necessary. Socio-cultural factors were generally presented negatively: New Zealand policies modeled a possible alternative. Based on their empirical work, the authors propose a matrix and a set of questions to guide the development and assessment of health policy

An Integrated Optimal Approach for Solar Powered Rural Water Distribution Systems in the Gambia

This is the final version. Available on open access from Scientific Research Publishing via the DOI in this recordIn the Gambia and across sub-Saharan Africa, reliable access to clean water and electrical power is constrained. As many rural water supply systems are already built, enhanced understanding of efficiencies and optimisation is required. Here, methods of integrating estimations of power outputs from solar photovoltaic arrays into gravity-fed water distribution network modelling are investigated. The effects of powering a rural water distribution system that is replenished with groundwater pumps that use solar power are investigated, along with the effect of this on other network design decisions. The water storage tank and pipework of a rural community with an estimated 2800 people and 28 standpipes from a borehole was selected. EPANET modelling software and genetic algorithms were used to run network optimisation simulations of: water tank location, elevation and volume; pipe diameter and configuration; and optimal system design in terms of cost. Different scenarios included producing supply, demand and required water storage curves, which could have practical application for rural water distribution system design. Indicative costs for theoretical water distribution networks will be useful for decision makers and planners

Writing the risk of cancer: cancer risk in policy documents.

In this paper we examine how cancer risk is written in cancer policy documents from the English speaking OECD nations. We offer an audit of the multiple ways in which cancer risk is conceptualized and presented in health policy and professional contexts with the long term aim of comparing this with lay conceptualizations. Our study sampled cancer policy documents produced by six nations, the World Health Organisation and the International Union for Cancer Control since 2000 and analysed them iteratively through questions and codes. Whilst the documents contained a comprehensive range of concepts and locations for cancer risk, our analysis found two predominant representations: firstly, well established metaphors that depict cancer as uniformly dreadful and life threatening; and secondly, through a concentration on five behavioural risk factors (tobacco smoking, drinking alcohol, inadequate nutrition, sun exposure and physical inactivity) and one bodily state (overweight). We discuss the implications of this dual focus and of other tensions within ideas about cancer risk that we identified for risk communication