Two-dimensional flow of foam around an obstacle: force measurements

A Stokes experiment for foams is proposed. It consists in a two-dimensional flow of a foam, confined between a water subphase and a top plate, around a fixed circular obstacle. We present systematic measurements of the drag exerted by the flowing foam on the obstacle, \emph{versus} various separately controlled parameters: flow rate, bubble volume, bulk viscosity, obstacle size, shape and boundary conditions. We separate the drag into two contributions, an elastic one (yield drag) at vanishing flow rate, and a fluid one (viscous coefficient) increasing with flow rate. We quantify the influence of each control parameter on the drag. The results exhibit in particular a power-law dependence of the drag as a function of the bulk viscosity and the flow rate with two different exponents. Moreover, we show that the drag decreases with bubble size, and increases proportionally to the obstacle size. We quantify the effect of shape through a dimensioned drag coefficient, and we show that the effect of boundary conditions is small.Comment: 26 pages, 13 figures, resubmitted version to Phys. Rev.

Publication des Principes mathématiques de la philosophie naturelle, par Emilie du Châtelet, femme de science au XVIIIe siècle (La)

Ce mémoire a pour objectif de montrer le rôle de femme de science de Madame du Châtelet au XVIIIe siècle en France, à travers l’étude de ses Principes mathématiques de la philosophie naturelle, traduction en français et commentaire des Principia de Newton. Ce travail utilise les dernières découvertes sur Madame du Châtelet, ainsi qu’une analyse de bibliographie matérielle d’un certain nombre d’exemplaires des Principes mathématiques

Lack of genetic structure in greylag goose (Anser anser) populations along the European Atlantic flyway

Greylag goose populations are steadily increasing in north-western Europe. Although individuals breeding in the Netherlands have been considered mainly sedentary birds, those fromScandinavia or northern Germany fly towards their winter quarters, namely over France as far as Spain. This study aimed to determine the genetic structure of these birds, and to evaluate how goose populations mix. We used mitochondrial DNA and microsatellites from individuals distributed throughout the European Atlantic flyway, from breeding sites in Norway and the Netherlands to stopover and wintering sites in northern and south-western France. The mtDNA marker (CR1 D-Loop, 288 bp sequence, 144 ind.) showed 23 different haplotypes. The genetic distances amongst individuals sampled in Norway, northern France and the Netherlands were low (range 0.012–0.013). Individuals in south-western France showed a slightly higher genetic distance compared to all other sampling areas (ranges 0.018–0.022). The NJ tree does not show evidence of any single clades grouping together all individuals fromthe same geographic area. Besides, individuals from each site are found in different branches. Bayesian clustering procedures on 14 microsatellites (169 individuals) did not detect any geographically distinct cluster, and a high genetic admixture was recorded in all studied areas except for the individuals from the breeding sites in Norway, which were genetically very close. Estimation of migration rates through Bayesian inference confirms the scenario for the current mixing of goose populations. Subjects Biodiversity, Zoology Keywords mtDNA, Microsatellites, Greylag goose, Genetic structure, France and Norwa

Cartografía en Francia, para el proyecto “Trame verte et bleue”, de las continuidades ecológicas de importancia nacional que constituyen los setos

Maintaining a dense ecological network for different habitats is a challenge to guarantee persistence of ecological processes at national scale. As cultural landscape favourable for biodiversity, bocage represents an important stake in terms of connectivity. In the context of the “Trame verte et bleue” project and the definition of its guidelines, we carried out a survey to propose a map of bocage ecological continuities of national significance. The process is based on a cartographic crossing between three data sources: two existing maps of land use and crop diversity, and an indicative map of ecological quality. The latter was produced representing specific richness of 11 bocage-dependent species in a grid. When the three criteria were visually satisfied in the manual cartographic crossing, structural and functional continuity was identified. The obtained map highlights 9 main indicative continuities. The results were confronted to local data and expertise to assess map relevance. The main objective of this work is to facilitate national coherence of regional ecological networksLa conservación de una red nacional de corredores ecológicos que sea lo suficientemente densa y que incluya diferentes tipos de sistemas naturales es un gran desafío a la hora de asegurar la perennidad de los procesos ecológicos que se desarrollan a gran escala. Entre estos corredores ecológicos, destacan por su importancia los setos y otras formaciones vegetales que aparecen en los paisajes cultivados. Estas formaciones vegetales permiten conciliar la actividad agrícola con la conservación de la biodiversidad. Para el proyecto “Trame verte et bleue” y la definición de sus grandes orientaciones, proponemos un mapa de Francia que incluye continuidades ecológicas importantes a nivel nacional. Para ello, hemos combinado manualmente tres fuentes cartográficas: un mapa de la densidad de setos, otro con la diversidad de cultivos y otro mapa que indica la presencia en una cuadrícula de once especies habituales de los setos y que tienen requerimientos ecológicos estrictos. Los grupos vegetales que destacaban visualmente siguiendo estos tres criterios cartográficos se han considerado como continuidades ecológicas nacionales relevantes desde un punto de vista funcional y estructural. El mapa obtenido presenta nueve grandes corredores a la escala nacional. Estos resultados han sido confrontados con estudios regionales y con cuestionarios a expertos. Esperamos que este mapa permita favorecer la coherencia de las tramas regionales de redes ecológicas en FranciaLe maintien d'un réseau suffisamment dense de continuités écologiques à l'échelle nationale couvrant différents types de milieux est un enjeu majeur pour assurer la pérennité des processus écologiques qui se déroulent à large échelle. Les bocages, milieux agricoles favorables à la biodiversité, sont concernés par ce défi. Dans le cadre du programme « Trame verte et bleue » et de la définition de ses orientations nationales, nous avons mené une réflexion afin de proposer une carte de grandes continuités écologiques bocagères. La démarche repose sur un croisement cartographique manuel entre: une carte de la densité de haies, une carte de la diversité des assolements et une carte indicatrice d'une certaine qualité écologique. Cette dernière carte représente la richesse spécifique par maille pour un ensemble de 11 espèces associées aux bocages et écologiquement exigeantes. Les ensembles présentant visuellement un fort intérêt selon ces trois critères cartographiques ont été considérés comme des continuités à la fois structurelles et fonctionnelles. Le résultat obtenu se présente sous la forme d’une carte indiquant 9 grandes continuités à l’échelle nationale. Une confrontation à l’expertise et à des études locales et régionales a permis de valider la pertinence de cette carte destinée à favoriser la cohérence nationale des trames écologiques régionales

Default from tuberculosis treatment in Tashkent, Uzbekistan; Who are these defaulters and why do they default?

<p>Abstract</p> <p>Background</p> <p>In Tashkent (Uzbekistan), TB treatment is provided in accordance with the DOTS strategy. Of 1087 pulmonary TB patients started on treatment in 2005, 228 (21%) defaulted. This study investigates who the defaulters in Tashkent are, when they default and why they default.</p> <p>Methods</p> <p>We reviewed the records of 126 defaulters (cases) and 132 controls and collected information on time of default, demographic factors, social factors, potential risk factors for default, characteristics of treatment and recorded reasons for default.</p> <p>Results</p> <p>Unemployment, being a pensioner, alcoholism and homelessness were associated with default. Patients defaulted mostly during the intensive phase, while they were hospitalized (61%), or just before they were to start the continuation phase (26%). Reasons for default listed in the records were various, 'Refusal of further treatment' (27%) and 'Violation of hospital rules' (18%) were most frequently recorded. One third of the recorded defaulters did not really default but continued treatment under 'non-DOTS' conditions.</p> <p>Conclusion</p> <p>Whereas patient factors such as unemployment, being a pensioner, alcoholism and homelessness play a role, there are also system factors that need to be addressed to reduce default. Such system factors include the obligatory admission in TB hospitals and the inadequately organized transition from hospitalized to ambulatory treatment.</p

Factors associated with default from treatment among tuberculosis patients in nairobi province, Kenya: A case control study

<p>Abstract</p> <p>Background</p> <p>Successful treatment of tuberculosis (TB) involves taking anti-tuberculosis drugs for at least six months. Poor adherence to treatment means patients remain infectious for longer, are more likely to relapse or succumb to tuberculosis and could result in treatment failure as well as foster emergence of drug resistant tuberculosis. Kenya is among countries with high tuberculosis burden globally. The purpose of this study was to determine the duration tuberculosis patients stay in treatment before defaulting and factors associated with default in Nairobi.</p> <p>Methods</p> <p>A Case-Control study; Cases were those who defaulted from treatment and Controls those who completed treatment course between January 2006 and March 2008. All (945) defaulters and 1033 randomly selected controls from among 5659 patients who completed treatment course in 30 high volume sites were enrolled. Secondary data was collected using a facility questionnaire. From among the enrolled, 120 cases and 154 controls were randomly selected and interviewed to obtain primary data not routinely collected. Data was analyzed using SPSS and Epi Info statistical software. Univariate and multivariate logistic regression analysis to determine association and Kaplan-Meier method to determine probability of staying in treatment over time were applied.</p> <p>Results</p> <p>Of 945 defaulters, 22.7% (215) and 20.4% (193) abandoned treatment within first and second months (intensive phase) of treatment respectively. Among 120 defaulters interviewed, 16.7% (20) attributed their default to ignorance, 12.5% (15) to traveling away from treatment site, 11.7% (14) to feeling better and 10.8% (13) to side-effects. On multivariate analysis, inadequate knowledge on tuberculosis (OR 8.67; 95% CI 1.47-51.3), herbal medication use (OR 5.7; 95% CI 1.37-23.7), low income (OR 5.57, CI 1.07-30.0), alcohol abuse (OR 4.97; 95% CI 1.56-15.9), previous default (OR 2.33; 95% CI 1.16-4.68), co-infection with Human immune-deficient Virus (HIV) (OR 1.56; 95% CI 1.25-1.94) and male gender (OR 1.43; 95% CI 1.15-1.78) were independently associated with default.</p> <p>Conclusion</p> <p>The rate of defaulting was highest during initial two months, the intensive phase of treatment. Multiple factors were attributed by defaulting patients as cause for abandoning treatment whereas several were independently associated with default. Enhanced patient pre-treatment counseling and education about TB is recommended.</p

Aeration of a Free Jet Above a Spillway

A study of air entrainment above an spillway aerator is presented and discussed with a dimensional analysis. We conclude that similitude of air entrainment processes for spillway aerator is not possible between model and prototype. New informations on the aeration region are presented and an analytical solution of the upper nappe entrainment is developed

Risk factors for tuberculosis treatment failure, default, or relapse and outcomes of retreatment in Morocco

<p>Abstract</p> <p>Background</p> <p>Patients with tuberculosis require retreatment if they fail or default from initial treatment or if they relapse following initial treatment success. Outcomes among patients receiving a standard World Health Organization Category II retreatment regimen are suboptimal, resulting in increased risk of morbidity, drug resistance, and transmission.. In this study, we evaluated the risk factors for initial treatment failure, default, or early relapse leading to the need for tuberculosis retreatment in Morocco. We also assessed retreatment outcomes and drug susceptibility testing use for retreatment patients in urban centers in Morocco, where tuberculosis incidence is stubbornly high.</p> <p>Methods</p> <p>Patients with smear- or culture-positive pulmonary tuberculosis presenting for retreatment were identified using clinic registries in nine urban public clinics in Morocco. Demographic and outcomes data were collected from clinical charts and reference laboratories. To identify factors that had put these individuals at risk for failure, default, or early relapse in the first place, initial treatment records were also abstracted (if retreatment began within two years of initial treatment), and patient characteristics were compared with controls who successfully completed initial treatment without early relapse.</p> <p>Results</p> <p>291 patients presenting for retreatment were included; 93% received a standard Category II regimen. Retreatment was successful in 74% of relapse patients, 48% of failure patients, and 41% of default patients. 25% of retreatment patients defaulted, higher than previous estimates. Retreatment failure was most common among patients who had failed initial treatment (24%), and default from retreatment was most frequent among patients with initial treatment default (57%). Drug susceptibility testing was performed in only 10% of retreatment patients. Independent risk factors for failure, default, or early relapse after initial treatment included male gender (aOR = 2.29, 95% CI 1.10-4.77), positive sputum smear after 3 months of treatment (OR 7.14, 95% CI 4.04-13.2), and hospitalization (OR 2.09, 95% CI 1.01-4.34). Higher weight at treatment initiation was protective. Male sex, substance use, missed doses, and hospitalization appeared to be risk factors for default, but subgroup analyses were limited by small numbers.</p> <p>Conclusions</p> <p>Outcomes of retreatment with a Category II regimen are suboptimal and vary by subgroup. Default among patients receiving tuberculosis retreatment is unacceptably high in urban areas in Morocco, and patients who fail initial tuberculosis treatment are at especially high risk of retreatment failure. Strategies to address risk factors for initial treatment default and to identify patients at risk for failure (including expanded use of drug susceptibility testing) are important given suboptimal retreatment outcomes in these groups.</p

Management of pulmonary tuberculosis patients in an urban setting in Zambia: a patient's perspective

<p>Abstract</p> <p>Background</p> <p>Zambia continues to grapple with a high tuberculosis (TB) burden despite a long running Directly Observed Treatment Short course programme. Understanding issues that affect patient adherence to treatment programme is an important component in implementation of a successful TB control programme. We set out to investigate pulmonary TB patient's attitudes to seek health care, assess the care received from government health care centres based on TB patients' reports, and to seek associations with patient adherence to TB treatment programme.</p> <p>Methods</p> <p>This was a cross-sectional study of 105 respondents who had been registered as pulmonary TB patients (new and retreatment cases) in Ndola District between January 2006 and July 2007. We administered a structured questionnaire, bearing questions to obtain individual data on socio-demographics, health seeking behaviour, knowledge on TB, reported adherence to TB treatment, and health centre care received during treatment to consenting respondents.</p> <p>Results</p> <p>We identified that respondents delayed to seek treatment (68%) even when knowledge of TB symptoms was high (78%) or when they suspected that they had TB (73%). Respondent adherence to taking medication was high (77%) but low adherence to submitting follow-up sputum (47%) was observed in this group. Similarly, caregivers educate their patients more often on the treatment of the disease (98%) and drug taking (100%), than on submitting sputum during treatment (53%) and its importance (54%). Respondent adherence to treatment was significantly associated with respondent's knowledge about the disease and its treatment (p < 0.0001), and with caregiver's adherence to treatment guidelines (p = 0.0027).</p> <p>Conclusions</p> <p>There is a need to emphasise the importance of submitting follow-up sputum during patient education and counselling in order to enhance patient adherence and ultimately treatment outcome.</p