Spatially-Correlated Microstructure and Superconductivity in Polycrystalline Boron-Doped Diamond

Scanning tunneling spectroscopies are performed below 100~mK on nano-crystalline boron-doped diamond films characterized by Transmission Electron Microscopy and transport measurements. We demonstrate a strong correlation between the local superconductivity strength and the granular structure of the films. The study of the spectral shape, amplitude and temperature dependence of the superconductivity gap enables us to differentiate intrinsically superconducting grains that follow the BCS model, from grains showing a different behavior involving the superconducting proximity effect

Light-driven liquid crystalline nonlinear oscillator under optical periodic forcing

An all-optically driven strategy to govern a liquid crystalline collective molecular nonlinear oscillator is discussed. It does not require external feedbacks of any kind while the oscillator and a time-depending perturbation both are sustained by incident light. Various dynamical regimes such as frequency -locked, quasiperiodic, forced and chaotic are observed in agreement with a theoretical approach developed in the limit of the plane wave approximation.Comment: 5 pages, 6 figures, submitted to Phys. Rev.

Sudden death in patients without structural heart disease

AbstractSudden unexpected cardiac death generally occurs in persons with known or previously unrecognized heart disease. However, it has become evident that it occurs often enough in patients without any identifiable structural abnormality to warrant the cardiologist's attention. Mostly, it concerns young, active, and otherwise healthy individuals. This paper focuses on various categories of patients with life-threatening events considered to have occurred on a solely “electrical” basis. Currently, several entities are recognized with distinct electrophysiological abnormalities, including Wolff-Parkinson-White syndrome, long QT syndrome, the Brugada syndrome, short-coupled torsade de pointes, and catecholamine-induced polymorphic ventricular tachyarrhythmia. The remaining patients without such distinct abnormalities are categorized as having idiopathic ventricular fibrillation. Although mechanical cardiac function may seem normal, such patients might have certain discrete anatomic abnormalities, unidentifiable with current investigational tools. Possibly in the future, with development of newer and more sophisticated tools (magnetic resonance imaging, positron emission tomography, genetic testing), some or all cases of idiopathic ventricular fibrillation must be redefined as having specific genetic and/or anatomic bases. All patients successfully resuscitated from cardiac arrest due to ventricular tachyarrhythmia without clear precipitating factors (acute myocardial infarction, severe electrolyte or metabolic disturbances) are at high risk of recurrences. Long-term prophylactic therapy is indicated. Contrasting with older belief, survivors of idiopathic ventricular fibrillation are now also considered high-risk patients. The implantable cardioverter-defibrillator appears to be the safest and most effective therapy

Hidden Consequences of Living in a Wormy World: Nematode-Induced Immune Suppression Facilitates Tuberculosis Invasion in African Buffalo

Most hosts are infected with multiple parasites, and responses of the immune system to co occurring parasites may influence disease spread. Helminth infection can bias the host immune response toward a T-helper type 2 Th2) over a type 1 Th1) response, impairing the host\u27s ability to control concurrent intracellular microparasite infections and potentially modifying disease dynamics. In humans, immune-mediated interactions between helminths and microparasites can alter host susceptibility to diseases such as HIV, tuberculosis TB), and malaria. However, the extent to which similar processes operate in natural animal populations and influence disease spread remains unknown. We used cross-sectional, experimental, and genetic studies to show that gastrointestinal nematode infection alters immunity to intracellular microparasites in free-ranging African buffalo Syncerus caffer). Buffalo that were more resistant to nematode infection had weaker Th1 responses, there was significant genotypic variation in nematode resistance, and anthelminthic treatment enhanced Th1 immunity. Using a disease dynamic model parameterized with empirical data, we found that nematode-induced immune suppression can facilitate the invasion of bovine TB in buffalo. In the absence of nematodes, TB failed to invade the system, illustrating the critical role nematodes may play in disease establishment. Our results suggest that helminths, by influencing the likelihood of microparasite invasion, may influence patterns of disease emergence in the wild

Evaluation De L’activité Acaricide De Quelques Biopesticides Sur L’acarien Tarsonème, Polyphagotarsonemus Latus Banks (Acari : Tarsonemidae) Infestant L’aubergine Gboma (Solanum Macrocarpon L.) Au Sud-Bénin

L’acarien tarsonème, Polyphagotarsonemus latus Banks, est un important ravageur de l’aubergine Gboma (Solanum macrocarpon L.), un légume-feuille de grande consommation au Bénin. La gestion de ce ravageur repose fondamentalement sur la lutte chimique avec toutes ses conséquences sur la santé et sur l’environnement ; d’où la nécessité de rechercher des solutions alternatives. Ainsi, la performance de trois biopesticides notamment huile de neem (Azadirachta indica A. Juss), extraits aqueux de hyptis (Hyptis suaveolens (L.) Poit, et du faux basilic (Ocimum gratissimum L), a été testée sur les œufs et adultes de P. latus au laboratoire de paires avec celle de Acarius et Sunpyrifos, deux acaricides chimiques communément utilisés au Bénin. Aussi, leurs effets sur les densités de population du ravageur et la productivité du Gboma ont-ils été évalués en plein champ. Au laboratoire, les taux moyens d’éclosion des œufs ont varié significativement entre traitements, allant 36 ± 5% à 80 ± 5% (P < 0,0001). Le plus fort taux d’éclosion a été enregistré sur le témoin et hyptis tandis que le plus fort d’éclosion a été enregistré avec Acarius suivi du Sunpyrifos et de l’huile de neem. Les taux de mortalité des adultes de P. latus ont également varié significativement entre les différents traitements allant de 43 ± 2% à 100% (P < 0,0001). Les plus faibles mortalités ont été enregistrées sur le témoin suivi de hyptis tandis que les plus forts taux ont été enregistrés, avec les doubles-doses de Acarius, Sunpyrifos et de l’huile de neem. Au champ, les densités moyennes par feuille des stades mobiles de P. latus ont varié significativement entre traitements, allant de 5,37 ± 0,59 et 2,71 ± 0,37 individus (P < 0,0001) ; les densités les plus fortes ayant été enregistrées sur le témoin tandis qu’aucune différence statistique n’a été observée entre les cinq autres traitements. Les plus fortes productivités de Gboma (kg/4 m2 ) ont été enregistrées avec l’huile de neem (13,65 ± 2,13), Sunpyrifos (11,10 ± 1,66) et Acarius (10,76 ± 1,32). Il s’en déduit qu’en attendant des études complémentaires, l’huile de neem peut être recommandée comme alternative aux acaricides chimiques contre P. latus sur les parcelles de Gboma au Sud-Bénin. The broad mite, Polyphagotarsonemus latus Banks is a key pest of the nightshade, commonly called Gboma eggplant (Solanum macrocarpon L.), a staple leafy vegetable in Benin. Management of this pest relies on chemical control despite its harmful environmental and sanitary impacts. It urgestherefore to search for alternative methods. In that respect, performances of some biopesticides including neem oil (Azadirachta indica A. Juss), aqueous extracts of Hyptis suaveolens (L.) Poit and of Ocimum gratissimum L. (clove basil), were tested on egg and adult stages of P. latus in laboratory in comparison to those of Acarius and Sunpyrifos, two chemical acaricides commonly used on vegetable farms in Southern Benin. In addition, their effects on the population densities of the pest and on the productivity of Gboma were evaluated in the field. In the laboratory, mean egg hatching rates varied significantly among treatments, ranging from 36 ± 5% to 80 ± 5% (P < 0,0001). The highest hatching rates were recorded with the control and hyptis treatments whereas the lowest hatching rates were recorded with Acarius followed by Sunpyrifos then neem oil treatments. Mortality rates of adult P. latus individuals also varied significantly among treatments, ranging from 43 ± 2% to 100% (P < 0,0001). The lowest mortality rates were recorded on the control followed by hyptis treatments whereas the highest mortalities were recorded with the double-doses of Acarius, Sunpyrifos and neem oil. In the field trials, mean densities of mobile stages of P. latus varied significantly among treatments, ranging from 5,37 ± 0,59 to 2,71 ± 0,37 individus (P < 0,0001). The highest densities were recorded on the control treatment whereas no significant differences were observed among the five other treatmentsThe highest productivities in fresh Gboma leaves on 4 m2 plot were recorded with neem oil (13.65 ± 2.13 kg), Sunpyrifos (11.1 ± 1.66 kg) and Acarius (10.76 ± 1.32 kg). Pending further studies, neem oil may be recommended as an alternative to chemical acaricides for the control of P. latus on Gboma plots in Southern Benin

La modélisation d'accompagnement : une méthode de recherche participative et adaptative

Ce chapitre vise à présenter la diversité dans la mise en ½uvre d'un processus de modélisation d'accompagnement, mais aussi les points communs qui en émergent. L'objectif est de décrire pour mieux comprendre, sans intention normative. Nous nous appuyons sur l'analyse des cas d'études et des documents listés dans l'introduction. Notre analyse rassemble des cas concrets et des pratiques qui se réclament de la modélisation d'accompagnement et qui seront donc considérés comme tels dans notre analyse. La compatibilité de la diversité observée avec le cadre d'une adhésion aux principes initiaux de la charte sort du cadre de ce chapitre, elle est traitée dans la conclusion générale de l'ouvrage

Theoretical biology - Comparing models of species abundance

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62867/1/nature04826.pd

Geometrization of metric boundary data for Einstein's equations

The principle part of Einstein equations in the harmonic gauge consists of a constrained system of 10 curved space wave equations for the components of the space-time metric. A well-posed initial boundary value problem based upon a new formulation of constraint-preserving boundary conditions of the Sommerfeld type has recently been established for such systems. In this paper these boundary conditions are recast in a geometric form. This serves as a first step toward their application to other metric formulations of Einstein's equations.Comment: Article to appear in Gen. Rel. Grav. volume in memory of Juergen Ehler