Toward a structural understanding of turbulent drag reduction: nonlinear coherent states in viscoelastic shear flows

Nontrivial steady flows have recently been found that capture the main structures of the turbulent buffer layer. We study the effects of polymer addition on these "exact coherent states" (ECS) in plane Couette flow. Despite the simplicity of the ECS flows, these effects closely mirror those observed experimentally: Structures shift to larger length scales, wall-normal fluctuations are suppressed while streamwise ones are enhanced, and drag is reduced. The mechanism underlying these effects is elucidated. These results suggest that the ECS are closely related to buffer layer turbulence.Comment: 5 pages, 3 figures, published version, Phys. Rev. Lett. 89, 208301 (2002

Neandertal Mandibular Molars from Hortus Cave, France: A Comparison of Crown Shapes Using Elliptical Fourier Analysis

Neandertal permanent mandibular molars are well represented at Hortus Cave, France, Sub-Phase IVb and Vb, providing an opportunity to assess intrapopulation and intersite shape variation. We expected the mandibular molars from Hortus cave, comprising Hortus II, Hortus IV, Hortus V and Hortus VI to cluster together, compared to Neandertals close in proximity, such as Malarnaud and La Quina 5 as well as those more distantly located such as Arcysur- Cure 1, Engis 2 and Scladina 4A-1. A single Neolithic cave burial from Maurenne Caverne de la Cave, Belgium (n = 11) is used to contextualize the degree of variation in the Hortus assemblage. From photographic images of the permanent molars, crown shapes were digitized and binarized. The resulting images were processed in R using elliptical Fourier analysis and the resulting amplitudes of the harmonics were subjected to principal components analysis and hierarchical clustering. Hortus II and Hortus V, both from Sub-Phase Vb, are relatively similar to one another in M1 crown shape, and are secondarily grouped with Hortus IV from Sub-Phase IVb. Maurenne Caverne de la Cave has a larger degree of variation in crown shape than the Hortus assemblage, and the Neandertals imperfectly cluster together and apart from the Neolithic sample for some multivariate comparisons. Variance in Neandertal molar crown shape can be primarily explained as the result of chronology. Hortus consistently groups with other MIS 3 Neandertals such as La Quina 5 and Engis 2, while those from MIS 5, represented by Scladina 4A-1 and Malarnaud are distinct as is Arcy-sur-Cure 1 from late MIS 3. Across the molars, the Hortus assemblage is most similar to La Quina 5 from Charente, Southwest France

Stretching of polymers in a random three-dimensional flow

Behavior of a dilute polymer solution in a random three-dimensional flow with an average shear is studied experimentally. Polymer contribution to the shear stress is found to be more than two orders of magnitude higher than in a laminar shear flow. The results indicate that the polymer molecules get strongly stretched by the random motion of the fluid.Comment: 4 pages, 3 figure

The diet of young Neandertals from France, Pech de l’Azé I and Hortus II, reconstructed using dental microwear texture analysis

Les adultes néandertaliens présentent des différences de régime alimentaire en fonction de leur paléohabitat. Nous examinons si les jeunes enfants néandertaliens de France datant du stade isotopique marins 3 montrent également ces distinctions alimentaires à partir de l’étude de la texture des micro-usures dentaires des deuxièmes molaires déciduales des individus Pech de l’Azé I, datant d’une phase froide-tempérée, et Hortus II, datant d’une phase froid-aride extrême. L’échantillon comparatif (n=76) comprend des molaires déciduales d’agriculteurs-cueilleurs provenant de trois grottes néolithiques de Belgique, dont Caverne de la Cave à Maurenne (n=5), Sclaigneaux (n=7) et Bois Madame (n=6), ainsi que des agriculteurs de l’époque romaine d’Herculanum (n=15) et médiévaux de Canterbury, Angleterre (n=43). Lorsque la complexité est comparée à l’anisotropie, Pech de l’Azé I présente une valeur élevée provenant de la mastication de plantes à parties dures ou de particules adhérentes, ou de la consommation d’aliments mal transformés ou chargés de silicates abrasifs. En revanche, Hortus II a une valeur faible, peut-être en raison de l’accès limité aux parties dures des plantes comme les graines et les noix. Toutefois, Pech de l’Azé I et Hortus II se ressemblent en présentant une faible valeur d’anisotropie qui est révélatrice de mouvements complexes des mâchoires lors de la mastication et sont différents des enfants humains néolithiques, romains et médiévaux qui ont tendance à avoir des valeurs plus élevées. Les régimes alimentaires des enfants néandertaliens diffèrent en fonction du paléohabitat et sont généralement plus diversifiés que ceux des producteurs d’aliments, qu’ils habitent des environnements boisés ou ouverts.Neandertal adults show differences in diet with respect to paleohabitat. To examine whether Neandertal children of France during Marine Isotope Stage 3 also show these dietary distinctions, the deciduous second molars of Pech de l’Azé I, from a cold-temperate period, and Hortus II from Sub-Phase Vb, an extreme cold-arid interval, were examined using dental microwear texture analysis. The comparative sample (n=76) includes deciduous molars from Neolithic forager-farmers of Belgium, including Caverne de la Cave at Maurenne (n=5), Sclaigneaux (n=7) and Bois Madame (n=6), Roman-era farmers from Herculaneum (n=15) and Medieval agriculturalists from Canterbury, England (n=43). When complexity is compared to anisotropy, Pech de l’Azé I exhibits an elevated value from the mastication of plants with hard parts or adherent particles, or the consumption of foods that were poorly processed or grit-laden, whereas Hortus II presents a low value, perhaps from limited access to hard plant parts such as seeds and nuts. However, Pech de l’Azé I and Hortus II resemble each other in having a low value for anisotropy, which is indicative of complicated movements of the jaws during mastication and are dissimilar to Neolithic, Roman and Medieval human children who tend to have higher values. The diets of Neandertal children differ with respect to paleohabitat and typically were more diverse than those of food producers regardless of whether they inhabited wooded or open environments

Drug-gene interactions of antihypertensive medications and risk of incident cardiovascular disease: a pharmacogenomics study from the CHARGE consortium

Background Hypertension is a major risk factor for a spectrum of cardiovascular diseases (CVD), including myocardial infarction, sudden death, and stroke. In the US, over 65 million people have high blood pressure and a large proportion of these individuals are prescribed antihypertensive medications. Although large long-term clinical trials conducted in the last several decades have identified a number of effective antihypertensive treatments that reduce the risk of future clinical complications, responses to therapy and protection from cardiovascular events vary among individuals. Methods Using a genome-wide association study among 21,267 participants with pharmaceutically treated hypertension, we explored the hypothesis that genetic variants might influence or modify the effectiveness of common antihypertensive therapies on the risk of major cardiovascular outcomes. The classes of drug treatments included angiotensin-converting enzyme inhibitors, beta-blockers, calcium channel blockers, and diuretics. In the setting of the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) consortium, each study performed array-based genome-wide genotyping, imputed to HapMap Phase II reference panels, and used additive genetic models in proportional hazards or logistic regression models to evaluate drug-gene interactions for each of four therapeutic drug classes. We used meta-analysis to combine study-specific interaction estimates for approximately 2 million single nucleotide polymorphisms (SNPs) in a discovery analysis among 15,375 European Ancestry participants (3,527 CVD cases) with targeted follow-up in a case-only study of 1,751 European Ancestry GenHAT participants as well as among 4,141 African-Americans (1,267 CVD cases). Results Although drug-SNP interactions were biologically plausible, exposures and outcomes were well measured, and power was sufficient to detect modest interactions, we did not identify any statistically significant interactions from the four antihypertensive therapy meta-analyses (Pinteraction > 5.0×10−8). Similarly, findings were null for meta-analyses restricted to 66 SNPs with significant main effects on coronary artery disease or blood pressure from large published genome-wide association studies (Pinteraction ≥ 0.01). Our results suggest that there are no major pharmacogenetic influences of common SNPs on the relationship between blood pressure medications and the risk of incident CVD

Low rank approximation of multidimensional data

In the last decades, numerical simulation has experienced tremendous improvements driven by massive growth of computing power. Exascale computing has been achieved this year and will allow solving ever more complex problems. But such large systems produce colossal amounts of data which leads to its own difficulties. Moreover, many engineering problems such as multiphysics or optimisation and control, require far more power that any computer architecture could achieve within the current scientific computing paradigm. In this chapter, we propose to shift the paradigm in order to break the curse of dimensionality by introducing decomposition to reduced data. We present an extended review of data reduction techniques and intends to bridge between applied mathematics community and the computational mechanics one. The chapter is organized into two parts. In the first one bivariate separation is studied, including discussions on the equivalence of proper orthogonal decomposition (POD, continuous framework) and singular value decomposition (SVD, discrete matrices). Then, in the second part, a wide review of tensor formats and their approximation is proposed. Such work has already been provided in the literature but either on separate papers or into a pure applied mathematics framework. Here, we offer to the data enthusiast scientist a description of Canonical, Tucker, Hierarchical and Tensor train formats including their approximation algorithms. When it is possible, a careful analysis of the link between continuous and discrete methods will be performed.IV Research and Transfer Plan of the University of SevillaInstitut CarnotJunta de AndalucíaIDEX program of the University of Bordeau

Nutritional status of iodine in pregnant women in Catalonia (Spain): study on hygiene-dietetic habits and iodine in urine

<p>Abstract</p> <p>Background</p> <p>It is a priority to achieve an adequate nutritional status of iodine during pregnancy since iodine deficiency in this population may have repercussions on the mother during both gestation and post partum as well as on the foetus, the neonate and the child at different ages. According to the WHO, iodine deficiency is the most frequent cause of mental retardation and irrreversible cerebral lesions around the world. However, few studies have been published on the nutritional status of iodine in the pregnant population within the Primary Care setting, a health care level which plays an essential role in the education and control of pregnant women. Therefore, <b>the aim of the present study </b>is: 1.- To know the hygiene-dietetic habits related to the intake of foods rich in iodine and smoking during pregnancy. 2.- To determine the prevalence of iodine deficiency and the factors associated with its appearance during pregnancy.</p> <p>Methods/design</p> <p>We will perform a cluster randomised, controlled, multicentre trial. Randomisation unit: Primary Care Team. Study population: 898 pregnant women over the age of 17 years attending consultation to a midwife during the first trimester of pregnancy in the participating primary care centres. Outcome measures: consumption of iodine-rich foods and iodine deficiency. Points of assessment: each trimester of the gestation. Intervention: group education during the first trimester of gestation on healthy hygiene-dietetic habits and the importance of an adequate iodine nutritional status. Statistical analysis: descriptive analysis of all variables will be performed as well as multilevel logistic regression. All analyses will be done carried out on an intention to treat basis and will be fitted for potential confounding factors and variables of clinical importance.</p> <p>Discussion</p> <p>Evidence of generalised iodine deficiency during pregnancy could lead to the promotion of interventions of prevention such as how to improve and intensify health care educational programmes for pregnant women.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov: <a href="http://www.clinicaltrials.gov/ct2/show/NCT01301768">NCT01301768</a></p