Hybrid spectral-particle method for the turbulent transport of a passive scalar

International audienceThis paper describes a novel hybrid method, combining a spectral and a particle method, to simulate the turbulent transport of a passive scalar. The method is studied from the point of view of accuracy and numerical cost. It leads to a significative speed up over more conventional grid-based methods and allows to address challenging Schmidt numbers. In particular, theoretical predictions of universal scaling in forced homogeneous turbulence are recovered for a wide range of Schmidt numbers for large, intermediate and small scales of the scalar

Multi-scale problems, high performance computing and hybrid numerical methods

International audienceThe turbulent transport of a passive scalar is an important and challenging problem in many applications in fluid mechanics. It involves different range of scales in the fluid and in the scalar and requires important computational resources. In this work we show how hybrid numerical methods, combining Eulerian and Lagrangian schemes, are natural tools to address this multi-scale problem. One in particular shows that in homogeneous turbulence experiments at various Schmidt numbers these methods allow to recover the theoretical predictions of universal scaling at a minimal cost. We also outline hybrid methods can take advantage of heterogeneous platforms combining CPU and GPU processors

Expenditure Cuts and Access to Healthcare Under the Great Recession in Europe: Income Groups Are Unequally Affected

Background: The Great Recession, starting in 2008, was characterized by an overall reduction in living standards. This pushed several governments across Europe to restrict expenditures, also in the area of healthcare. These austerity measures are known to have affected access to healthcare, probably unevenly among social groups. This study examines the unequal effects of retrenchment in healthcare expenditures on access to medical care for different income groups across European countries. Method: Using data of two waves (2008 and 2014) of the European Union Statistics of Income and Living Conditions survey (EU-SILC), a difference-in-differences (DD) approach was used to analyse the overall change in unmet medical needs over time within and between countries. By adding another interaction, the differences in the effects between income quintiles (difference-in-difference-in-differences: DDD) were estimated. To do so, comparisons between two pairs of a treatment and a control case were made: Iceland versus Sweden, and Ireland versus the United Kingdom. These comparisons are made between countries with recessions equal in magnitude, but with different levels of healthcare cuts. This strategy allows isolating the effect of cuts, net of the severity of the recession. Results: The DD-estimates show a higher increase of unmet medical needs during the Great Recession in the treatment cases (Iceland vs. Sweden: + 3.24 pp.; Ireland vs. the United Kingdom: + 1.15 pp). The DDD-estimates show different results over the two models. In Iceland, the lowest income groups had a higher increase in unmet medical needs. This was not the case in Ireland, where middle-class groups saw their access to healthcare deteriorate more. Conclusion: Restrictions on health expenditures during the Great Recession caused an increase in self-reported unmet medical needs. The burden of these effects is not equally distributed; in some cases, the lower-income groups suffer most. The case of Ireland, nevertheless, shows that certain policy measures may relatively spare lower-income groups while affecting middle-class income groups more. These results bring in evidence that policies can reduce and even overshoot the general effect of income inequalities on access to healthcare

The unequal effects of austerity measures between income-groups on the access to healthcare : a quasi-experimental approach

Background The Great Recession, starting in 2008, was characterized by an overall reduction in living standards. This pushed several governments across Europe to restrict expenditures, also in the area of healthcare. These austerity measures are known to have affected access to healthcare, probably unevenly among social groups. This study examines the unequal effects of retrenchment in healthcare expenditures on access to medical care for different income groups across European countries. Method Using data of two waves (2008 and 2014) of the European Union Statistics of Income and Living Conditions survey (EU-SILC), a difference-in-differences (DD) approach was used to analyse the overall change in unmet medical needs over time within and between countries. By adding another interaction, the differences in the effects between income quintiles (difference-in-difference-in-differences: DDD) were estimated. To do so, comparisons between two pairs of a treatment and a control case were made: Iceland versus Sweden, and Ireland versus the United Kingdom. These comparisons are made between countries with recessions equal in magnitude, but with different levels of healthcare cuts. This strategy allows isolating the effect of cuts, net of the severity of the recession. Results The DD-estimates show a higher increase of unmet medical needs during the Great Recession in the treatment cases (Iceland vs. Sweden: + 3.24 pp.; Ireland vs. the United Kingdom: + 1.15 pp). The DDD-estimates show different results over the two models. In Iceland, the lowest income groups had a higher increase in unmet medical needs. This was not the case in Ireland, where middle-class groups saw their access to healthcare deteriorate more. Conclusion Restrictions on health expenditures during the Great Recession caused an increase in self-reported unmet medical needs. The burden of these effects is not equally distributed; in some cases, the lower-income groups suffer most. The case of Ireland, nevertheless, shows that certain policy measures may relatively spare lower-income groups while affecting middle-class income groups more. These results bring in evidence that policies can reduce and even overshoot the general effect of income inequalities on access to healthcare

Community health workers as a strategy to tackle psychosocial suffering due to physical distancing : a randomized controlled trial

Background: During the COVID-19 pandemic, many primary care professionals were overburdened and experienced difficulties reaching vulnerable patients and meeting the increased need for psychosocial support. This randomized controlled trial (RCT) tested whether a primary healthcare (PHC) based community health worker (CHW) intervention could tackle psychosocial suffering due to physical distancing measures in patients with limited social networks. Methods: CHWs provided 8 weeks of tailored psychosocial support to the intervention group. Control group patients received ‘care as usual’. The impact on feelings of emotional support, social isolation, social participation, anxiety and fear of COVID-19 were measured longitudinally using a face-to-face survey to determine their mean change from baseline. Self-rated change in psychosocial health at 8 weeks was determined. Results: We failed to find a significant effect of the intervention on the prespecified psychosocial health measures. However, the intervention did lead to significant improvement in self-rated change in psychosocial health. Conclusions: This study confirms partially the existing evidence on the effectiveness of CHW interventions as a strategy to address mental health in PHC in a COVID context. Further research is needed to elaborate the implementation of CHWs in PHC to reach vulnerable populations during and after health crises

Iminosugar inhibitors of carbohydrate-active enzymes that underpin cereal grain germination and endosperm metabolism

Starch is a major energy store in plants. It provides most of the calories in the human diet and, as a bulk commodity, it is used across broad industry sectors. Starch synthesis and degradation are not fully understood, owing to challenging biochemistry at the liquid/solid interface and relatively limited knowledge about the nature and control of starch degradation in plants. Increased societal and commercial demand for enhanced yield and quality in starch crops requires a better understanding of starch metabolism as a whole. Here we review recent advances in understanding the roles of carbohydrate-active enzymes in starch degradation in cereal grains through complementary chemical and molecular genetics. These approaches have allowed us to start dissecting aspects of starch degradation and the interplay with cell-wall polysaccharide hydrolysis during germination. With a view to improving and diversifying the properties and uses of cereal grains, it is possible that starch degradation may be amenable to manipulation through genetic or chemical intervention at the level of cell wall metabolism, rather than simply in the starch degradation pathway per se

Gender and highbrow cultural participation in Europe : the effect of societal gender equality and development

Existing individual-level research links women's higher participation in high-status cultural activities to their position in work and family spheres. This article studies how cross-national variation in women's and men's cultural participation relates to societal care- and work-related gender equality and development. Multilevel analyses on Eurobarometer data (2013) indicate that male engagement in the feminine domain of care and societal development stimulates frequent participation in highbrow culture, but more for men than for women, thus partly explaining gender gap variation in highbrow cultural participation across European Union countries. We conclude that men play an important but underestimated role in the explanation of the gender gap

A multilevel perspective on the health effect of social capital : evidence for the relative importance of individual social capital over neighborhood social capital

Employing a multilevel perspective on the health effects of social capital, this study analyzes how individual and neighborhood differences in self-rated health in Ghent (Belgium), relate to individual and collective social mechanisms, when taking demographic and socioeconomic characteristics of individuals into account. This study estimates the health effects of social trust, informal social control and disorder at the neighborhood level and social support and network size at the individual level, using indicators indebted to both the normative and resource-based approaches to social capital. Instead of the mere aggregation of individual indicators of social capital, this study uses the key informant technique as a methodologically superior measurement of neighborhood social capital, which combined with a multilevel analysis strategy, allows to disentangle the health effects of individual and neighborhood social capital. The analysis highlights the health benefits of individual social capital, i.e., individual social support and network size. The study indicates that controlling for individual demographic and socioeconomic characteristics reduces the effect of the neighborhood-level counterparts and the neighborhood characteristics social trust and neighborhood disorder have significant, but small health effects. In its effects on self-rated health, social capital operates on the individual level, rather than the neighborhood level

Parameter estimation to study the immediate impact of aortic cross-clamping using reduced order models

Aortic cross-clamping is a common strategy during vascular surgery, however, its instantaneous impact on hemodynamics is unknown. We, therefore, developed two numerical models to estimate the immediate impact of aortic clamping on the vascular properties. To assess the validity of the models, we recorded continuous invasive pressure signals during abdominal aneurysm repair surgery, immediately before and after clamping. The first model is a zero-dimensional (0D) three-element Windkessel model, which we coupled to a gradient-based parameter estimation algorithm to identify patient-specific parameters such as vascular resistance and compliance. We found a 10% increase in the total resistance and a 20% decrease in the total compliance after clamping. The second model is a nine-artery network corresponding to an average human body in which we solved the one-dimensional (1D) blood flow equations. With a similar parameter estimation method and using the results from the 0D model, we identified the resistance boundary conditions of the 1D network. Determining the patient-specific total resistance and the distribution of peripheral resistances through the parameter estimation process was sufficient for the 1D model to accurately reproduce the impact of clamping on the pressure waveform. Both models gave an accurate description of the pressure wave and had a high correlation (R2 >.95) with experimental blood pressure data.Fil: Ventre, Jeanne. Centre National de la Recherche Scientifique; FranciaFil: Politi, Teresa. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Fisiología y Biofísica Bernardo Houssay. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología y Biofísica Bernardo Houssay; ArgentinaFil: Fernández, Juan M.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Fisiología y Biofísica Bernardo Houssay. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología y Biofísica Bernardo Houssay; ArgentinaFil: Ghigo, Arthur R.. Université de Toulouse; FranciaFil: Gaudric, Julien. Centre National de la Recherche Scientifique; Francia. Université de Toulouse; FranciaFil: Wray, Sandra. Universidad Favaloro; ArgentinaFil: Lagaert, Jean Baptiste. Université Paris Sud; FranciaFil: Armentano, Ricardo Luis. Universidad de la República; UruguayFil: Capurro, Claudia Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Fisiología y Biofísica Bernardo Houssay. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología y Biofísica Bernardo Houssay; ArgentinaFil: Fullana, José Maria. Centre National de la Recherche Scientifique; FranciaFil: Lagrée, Pierre Yves. Centre National de la Recherche Scientifique; Franci