Fast occlusion sweeping

Abstract. While realistic illumination significantly improves the visual quality and perception of rendered images, it is often very expensive to compute. In this paper, we propose a new algorithm for embedding a global ambient occlusion computation within the fast sweeping algorithm while determining isosurfaces. With this method we can approximate ambient occlusion for rendering volumetric data with minimal additional cost over fast sweeping. We compare visualizations rendered with our algorithm to visualizations computed with only local shading, and with a ambient occlusion calculation using Monte Carlo sampling method. We also show how this method can be used for approximating low frequency shadows and subsurface scattering. Realistic illumination techniques used in digitally synthesized images are known to greatly enhance the perception of shape. This is as true for renderings of volume data as it is for geometric models. For example, Qiu et al. [1] used full global illumination techniques to improve visualizations of volumetric data, and Stewart [2] shows how computation of local ambient occlusion enhances the perception of grooves in a brain CT scanned dataset. Tarini et al. In this paper, we provide a new solution for ambient occlusion computation that is significantly faster than existing techniques. The method integrates well with a volumetric ray marching algorithm implemented on the GPU. While not a full global illumination solution, ambient occlusion provides a more realistic illumination model than does local illumination, and permits the use of realistic light sources, like skylights. For accelerating our ray marching algorithm, we build a volumetric signed distance field using the fast sweeping method, and we embed our ambient occlusion approximatio

Socioeconomic Status, Structural and Functional Measures of Social Support, and Mortality: The British Whitehall II Cohort Study, 1985–2009

The authors examined the associations of social support with socioeconomic status (SES) and with mortality, as well as how SES differences in social support might account for SES differences in mortality. Analyses were based on 9,333 participants from the British Whitehall II Study cohort, a longitudinal cohort established in 1985 among London-based civil servants who were 35–55 years of age at baseline. SES was assessed using participant's employment grades at baseline. Social support was assessed 3 times in the 24.4-year period during which participants were monitored for death. In men, marital status, and to a lesser extent network score (but not low perceived support or high negative aspects of close relationships), predicted both all-cause and cardiovascular mortality. Measures of social support were not associated with cancer mortality. Men in the lowest SES category had an increased risk of death compared with those in the highest category (for all-cause mortality, hazard ratio = 1.59, 95% confidence interval: 1.21, 2.08; for cardiovascular mortality, hazard ratio = 2.48, 95% confidence interval: 1.55, 3.92). Network score and marital status combined explained 27% (95% confidence interval: 14, 43) and 29% (95% confidence interval: 17, 52) of the associations between SES and all-cause and cardiovascular mortality, respectively. In women, there was no consistent association between social support indicators and mortality. The present study suggests that in men, social isolation is not only an important risk factor for mortality but is also likely to contribute to differences in mortality by SES

Do social inequalities in health widen or converge with age? Longitudinal evidence from three cohorts in the West of Scotland

Background: Existing studies are divided as to whether social inequalities in health widen or converge as people age. In part this is due to reliance on cross-sectional data, but also among longitudinal studies to differences in the measurement of both socioeconomic status (SES) and health and in the treatment of survival effects. The aim of this paper is to examine social inequalities in health as people age using longitudinal data from the West of Scotland Twenty-07 Study to investigate the effect of selective mortality, the timing of the SES measure and cohort on the inequality patterns. Methods. The Twenty-07 Study has followed three cohorts, born around 1932, 1952 and 1972, from 1987/8 to 2007/8; 4,510 respondents were interviewed at baseline and, at the most recent follow-up, 2,604 were interviewed and 674 had died. Hierarchical repeated-measures models were estimated for self-assessed health status, with and without mortality, with baseline or time-varying social class, sex and cohort. Results: Social inequalities in health emerge around the age of 30 after which they widen until the early 60s and then begin to narrow, converging around the age of 75. This pattern is a result of those in manual classes reporting poor health at younger ages, with the gap narrowing as the health of those in non-manual classes declines at older ages. However, employing a more proximal measure of SES reduces inequalities in middle age so that convergence of inequalities is not apparent in old age. Including death in the health outcome steepens the health trajectories at older ages, especially for manual classes, eliminating the convergence in health inequalities, suggesting that healthy survival effects are important. Cohort effects do not appear to affect the pattern of inequalities in health as people age in this study. Conclusions: There is a general belief that social inequalities in health appear to narrow at older ages; however, taking account of selective mortality and employing more proximal measures of SES removes this convergence, suggesting inequalities in health continue into old age. © 2011 Benzeval et al; licensee BioMed Central Ltd

Moment Closure - A Brief Review

Moment closure methods appear in myriad scientific disciplines in the modelling of complex systems. The goal is to achieve a closed form of a large, usually even infinite, set of coupled differential (or difference) equations. Each equation describes the evolution of one "moment", a suitable coarse-grained quantity computable from the full state space. If the system is too large for analytical and/or numerical methods, then one aims to reduce it by finding a moment closure relation expressing "higher-order moments" in terms of "lower-order moments". In this brief review, we focus on highlighting how moment closure methods occur in different contexts. We also conjecture via a geometric explanation why it has been difficult to rigorously justify many moment closure approximations although they work very well in practice.Comment: short survey paper (max 20 pages) for a broad audience in mathematics, physics, chemistry and quantitative biolog

Ionizing Organic Compound Based Nanocomposites for Efficient Gamma-Ray Sensor

No abstract availabl

Liax Is a Surrogate Marker For Cell Envelope Stress and Daptomycin Non-Susceptibility in Enterococcus Faecium

Daptomycin (DAP) is often used as a first-line therapy to treat vancomycin-resistan

When does poor subjective financial position hurt the elderly? Testing the interaction with educational attainment using a national representative longitudinal survey

<p>Abstract</p> <p>Background</p> <p>Several studies have demonstrated that perceived financial status has a significant impact on health status among the elderly. However, little is known about whether such a subjective perception interacts with objective socioeconomic status (SES) measures such as education that affect the individual's health.</p> <p>Methods</p> <p>This research used data from the Survey of Health and Living Status of the Middle Age and Elderly in Taiwan (SHLS) conducted by the Bureau of Health Promotion, Department of Health in Taiwan. Waves 1996, 1999 and 2003 were used. The sample consisted of 2,387 elderly persons. The interactive effects of self-rated satisfaction with financial position and educational attainment were estimated. Self-rated health (SRH), depressive symptom (measured by CES-D) and mortality were used to measure health outcomes.</p> <p>Results</p> <p>Significant interaction effect was found for depressive symptoms. Among those who were dissatisfied with their financial position, those who were illiterate had an odds ratio (OR) of 8.3 (95% CI 4.9 to 14.0) for having depressive symptoms compared with those who were very satisfied with their financial position. The corresponding OR for those with college or above was only 2.7 (95% CI 1.0 to 7.3). No significant interaction effect was found for SRH and mortality.</p> <p>Conclusions</p> <p>Although poor financial satisfaction was found to be related to poorer health, the strongest association for this effect was observed among those with low educational attainment, and this is especially true for depressive symptoms. Subjective financial status among the elderly should be explored in conjunction with traditional measures of SES.</p

Postharvest losses of fruit and vegetables during retail and in consumers’ homes: Quantifications, causes, and means of prevention

The issue of food loss and waste (FLW) reduction has recently achieved much public attention as part of worldwide efforts to combat global hunger and improve food security. Studies conducted by various international and national organizations led by the FAO indicated that about one third of all food produced on the planet and about a half of all fruit and vegetables (F&V) are lost and not consumed. FLW occurs during five key stages of the food supply chain: agricultural production, postharvest handling and storage, processing, distribution, and consumption. Large portions of FLW in developed countries occur during retail and consumption, and are largely related to logistic management operations and consumer behaviors. In light of the great importance of FLW reduction, the United Nations set up in September 2015 an ambitious goal to halve per capita global food waste by 2030, and this decision was adapted by the US Federal Government, the EU Parliament, and many other countries. This first Adel Kader review article is dedicated to the subject of F&V losses during retail and consumption, and contains the following chapters: 1) Introduction of the problem of global food losses; 2) Quantifications of F&V losses during retail and consumption in the UK, US and other countries; 3) Causes and consumer decisions related to F&V wastage; 4) Emerging new technologies for prevention of F&V losses, including advances in logistics and cold chain management, retail packaging and technological innovations; 5) Other means to reduce F&V losses, including consumer awareness campaigns, advertisement of home storage instructions and policy and legislative measures. Due to the great importance of reducing F&V losses, we encourage postharvest researchers to become more engaged with logistics and food supply-chain operations, and to conduct multidisciplinary research incorporating consumer behavior studies into postharvest research

The power of social media storytelling in destination branding.

A large part of the global population is now connected in online social networks in social media where they share experiences and stories and consequently influence each other’s perceptions and buying behaviour. This poses a distinct challenge for destination management organisations, who must cope with a new reality where destination brands are increasingly the product of people’s shared tourism experiences and storytelling in social networks, rather than marketing strategies. This article suggests a novel interpretation on how these online social networks function with regard to generating engagement and stimulating circulation of brand stories by offering a conceptual framework based on the sociological concepts of storytelling, performance, performativity, and mobility. These concepts are characterised as ‘technologies of power’, for their role in shaping the social mechanisms in social media. VisitDenmark, the DMO of Denmark, is used as a case to put the framework into practice. The case demonstrates how DMOs can use the framework to strengthen their social media branding, and five practical recommendations for how to do so are provided