The Marangoni flow of soluble amphiphiles

Surfactant distribution heterogeneities at a fluid/fluid interface trigger the Marangoni effect, i.e. a bulk flow due to a surface tension gradient. The influence of surfactant solubility in the bulk on these flows remains incompletely characterized. Here we study Marangoni flows sustained by injection of hydrosoluble surfactants at the air/water interface. We show that the flow extent increases with a decrease of the critical micelle concentration, i.e. the concentration at which these surfactants self-assemble in water. We document the universality of the surface velocity field and predict scaling laws based on hydrodynamics and surfactant physicochemistry that capture the flow features.Comment: 5 pages, 4 figures, submitte

The spreading of hydrosoluble surfactants on water

International audienceHeterogeneities in the distribution of surfactants at an interface between two fluids create a gradient of interfacial tension, which triggers the Marangoni effect, i.e., a bulk flow in the two phases surrounding the interface. The Marangoni effect is used to enhance the spreading of liquids on substrates, and some living organisms rely on this to move at the surface of water. It can also impair processes such as surface coating

Large-Scale Transition of Economic Systems Do CEECs Converge Towards Western Prototypes?

In order to identify convergence patterns among the group of Central and Eastern European Countries (CEECs) we analyze clusters of traditional OECD countries, i.e. EU-15 plus Norway and Switzerland, Anglo-Saxon non-EU countries plus Japan, and CEECs based on macro data on government regulation and spending instead of micro data on firm relations and market characteristics as is usually applied in Varieties-of-Capitalism (VoC) analysis. This framework is supposed to incorporate some of the critique that has been expressed towards the traditional VoCapproach, especially its ignorance of government spending and performance. We acknowledge for the transition aspect by looking at cluster history and principal component analysis for periods of transition. Our analysis reveals that there is consolidation rather than convergence with CEECs being divided in clusters leaning towards CME and LME prototypes respectively. Overall, there are worlds of redistribution within which clusters differ with respect to their mix of - negatively correlated - regulation and innovation. Interestingly, CEECs do not mix up with Mediterranean MMEs, which indeed provide a kind of worst case setting, while Scandinavian CMEs as well as traditional LMEs provide a kind of role model within their respective worlds of redistribution

Changes of overweight and obesity in the adult Swiss population according to educational level, from 1992 to 2007

In many high income developed countries, obesity is inversely associated with educational level. In some countries, a widening gap of obesity between educational groups has been reported. The aim of this study was to assess trends in body mass index (BMI) and in prevalence of overweight and obesity and their association with educational level in the adult Swiss population. Four cross-sectional National health interview surveys conducted in 1992/93 (n = 14,521), 1997 (n = 12,474), 2002 (n = 18,908) and 2007 (n = 17,879) using representative samples of the Swiss population (age range 18-102 years). BMI was derived from self-reported data. Overweight was defined as BMI > or = 25 and <30 kg/m(2), and obesity as BMI > or = 30 kg/m(2). Mean (+/- standard deviation) BMI increased from 24.7 +/- 3.6 in 1992/3 to 25.4 +/- 3.6 kg/m2 in 2007 in men and 22.8 +/- 3.8 to 23.7 +/- 4.3 kg/m(2) in women. Between 1992/3 and 2007, the prevalence of overweight + obesity increased from 40.4% to 49.5% in men and from 22.3% to 31.3% in women, while the prevalence of obesity increased from 6.3% to 9.4% in men and from 4.9% to 8.5% in women. The rate of increase in the prevalence of obesity was greater between 1992/3 and 2002 (men: +0.26%/year; women: +0.31%/year) than between 2002 and 2007 (men: +0.10%/year; women: +0.10%/year). A sizable fraction (approximately 25%) of the increasing mean BMI was due to increasing age of the participants over time. The increase was larger in low than high education strata of the population. BMI was strongly associated with low educational level among women and this gradient remained fairly constant over time. A weaker similar gradient by educational level was apparent in men, but it tended to increase over time. In Switzerland, overweight and obesity increased between 1992 and 2007 and was associated with low education status in both men and women. A trend towards a stabilization of mean BMI levels was noted in most age categories since 2002. The increase in the prevalence of obesity was larger in low education strata of the population. These findings suggest that obesity preventive measures should be targeted according to educational level in Switzerland

Seasonal and Regional Dynamics of M. ulcerans Transmission in Environmental Context: Deciphering the Role of Water Bugs as Hosts and Vectors

Buruli ulcer, caused by Mycobacterium ulcerans, is a devastating skin disease. Most cases of Buruli ulcer occur in poor rural communities. As a result, treatment is frequently sought too late and about 25% of those infected—particularly children—become permanently disabled. Outbreaks of Buruli ulcer have always been associated with swampy areas. However, the route(s) of bacillus transmission is (are) still unclear. This Mycobacterium species resides in water where it colonizes many ecological niches such as aquatic plants, herbivorous animals and predatory/carnivorous insects. For several years the role of water bugs as hosts and vectors of M. ulcerans was suspected and was demonstrated under laboratory conditions. The aim of this work was to further assess the role of water bugs as hosts and vectors of M. ulcerans in environmental context. This work identifies several water bug families as hosts of M. ulcerans in Buruli ulcer endemic area. The detection of bacilli in saliva of human biting insects provides further evidence for their role in M. ulcerans transmission. Interestingly, three of these insects are good flyers, and as such could participate in M. ulcerans dissemination

Análise das redes interpessoais: aplicação na realidade de uma equipe de enfermagem atuando em unidade de hematologia

A equipe de Enfermagem do Serviço de Hematologia depara-se constantemente com situações de sofrimento intenso, podendo afetar sua homeostase. Considerando o postulado acerca da tendência à atualização do ser humano, as redes interpessoais podem ser benéficas, disponibilizando suportes para atualização da pessoa, que passa a transformar sua energia em comportamento útil, favorecendo o desempenho de funções e promovendo saúde. Este estudo foi realizado sobre a metodologia de análise das redes sociais, com o objetivo de analisar a rede interpessoal dos componentes de uma equipe de Enfermagem, que atua em unidade de hematologia de um hospital-escola na cidade de Fortaleza-CE. Foi realizado no ano de 2009, com 10 informantes-chaves. Os dados foram coletados no questionário gerador de nomes e qualificador da relação, processados nos programas: UCINET 6.123 e NETDRAW 2.38. O emprego da metodologia de análise de redes sociais permitiu reunir elementos elucidativos acerca da estrutura do grupo, sendo possível, a partir daí, tecer considerações acerca da posição ocupada pelos indivíduos, bem como do núcleo de relações constituído ao redor de cada um.The nursing team of the Hematology Service are constantly facing situations of intense suffering and this can affect their homeostasis. Considering the premise according to which human beings tend to upgrade themselves, interpersonal networks may be beneficial, providing support so that the person can upgrade herself, and starts to transform her energy into useful behavior, favoring the performance of duties and promoting health. This study employed the methodology of Social Network Analysis, and it aimed to analyze the interpersonal network of the members of a nursing team that work in the hematology unit of a hospital-school in the city of Fortaleza, Northeastern Brazil. The study was conducted in 2006, with ten key informants. Data were collected through a questionnaire that generates names and evaluates the relationship, and were processed by the programs: UCINET 6.123 and NETDRAW 2.38. The use of Social Network Analysis enabled us to learn about the structure of the group. Based on this, it was possible to make considerations about the position occupied by the individuals and about the nucleus of relationships constituted around each one of them

Malaria vector research and control in Haiti: a systematic review

BACKGROUND: Haiti has a set a target of eliminating malaria by 2020. However, information on malaria vector research in Haiti is not well known. This paper presents results from a systematic review of the literature on malaria vector research, bionomics and control in Haiti. METHODS: A systematic search of literature published in French, Spanish and English languages was conducted in 2015 using Pubmed (MEDLINE), Google Scholar, EMBASE, JSTOR WHOLIS and Web of Science databases as well other grey literature sources such as USAID, and PAHO. The following search terms were used: malaria, Haiti, Anopheles, and vector control. RESULTS: A total of 132 references were identified with 40 high quality references deemed relevant and included in this review. Six references dealt with mosquito distribution, seven with larval mosquito ecology, 16 with adult mosquito ecology, three with entomological indicators of malaria transmission, eight with insecticide resistance, one with sero-epidemiology and 16 with vector control. In the last 15 years (2000–2015), there have only been four published papers and three-scientific meeting abstracts on entomology for malaria in Haiti. Overall, the general literature on malaria vector research in Haiti is limited and dated. DISCUSSION: Entomological information generated from past studies in Haiti will contribute to the development of strategies to achieve malaria elimination on Hispaniola. However it is of paramount importance that malaria vector research in Haiti is updated to inform decision-making for vector control strategies in support of malaria elimination

Association of the PHACTR1/EDN1 genetic locus with spontaneous coronary artery dissection

Background: Spontaneous coronary artery dissection (SCAD) is an increasingly recognized cause of acute coronary syndromes (ACS) afflicting predominantly younger to middle-aged women. Observational studies have reported a high prevalence of extracoronary vascular anomalies, especially fibromuscular dysplasia (FMD) and a low prevalence of coincidental cases of atherosclerosis. PHACTR1/EDN1 is a genetic risk locus for several vascular diseases, including FMD and coronary artery disease, with the putative causal noncoding variant at the rs9349379 locus acting as a potential enhancer for the endothelin-1 (EDN1) gene. Objectives: This study sought to test the association between the rs9349379 genotype and SCAD. Methods: Results from case control studies from France, United Kingdom, United States, and Australia were analyzed to test the association with SCAD risk, including age at first event, pregnancy-associated SCAD (P-SCAD), and recurrent SCAD. Results: The previously reported risk allele for FMD (rs9349379-A) was associated with a higher risk of SCAD in all studies. In a meta-analysis of 1,055 SCAD patients and 7,190 controls, the odds ratio (OR) was 1.67 (95% confidence interval [CI]: 1.50 to 1.86) per copy of rs9349379-A. In a subset of 491 SCAD patients, the OR estimate was found to be higher for the association with SCAD in patients without FMD (OR: 1.89; 95% CI: 1.53 to 2.33) than in SCAD cases with FMD (OR: 1.60; 95% CI: 1.28 to 1.99). There was no effect of genotype on age at first event, P-SCAD, or recurrence. Conclusions: The first genetic risk factor for SCAD was identified in the largest study conducted to date for this condition. This genetic link may contribute to the clinical overlap between SCAD and FMD