Dense stellar matter with trapped neutrinos under strong magnetic fields

We investigate the effects of strong magnetic fields on the equation of state of dense stellar neutrino-free and neutrino-trapped matter. Relativistic nuclear models both with constant couplings (NLW) and with density dependent parameters (DDRH) and including hyperons are considered . It is shown that at low densities neutrinos are suppressed in the presence of the magnetic field. The magnetic field reduces the strangeness fraction of neutrino-free matter and increases the strangeness fraction of neutrino-trapped matter. The mass-radius relation of stars described by these equations of state are determined. The magnetic field makes the overall equation of state stiffer and the stronger the field the larger the mass of maximum mass star and the smaller the baryon density at the center of the star. As a consequence in the presence of strong magnetic fields the possibility that a protoneutron star evolves to a blackhole is smaller.Comment: 18 pages, 13 figures, 5 tables, submitted to J. Phys.

Warm and dense stellar matter under strong magnetic fields

We investigate the effects of strong magnetic fields on the equation of state of warm stellar matter as it may occur in a protoneutron star. Both neutrino free and neutrino trapped matter at a fixed entropy per baryon are analyzed. A relativistic mean field nuclear model, including the possibility of hyperon formation, is considered. A density dependent magnetic field with the magnitude $10^{15}$ G at the surface and not more than $3\times 10^{18}$ G at the center is considered. The magnetic field gives rise to a neutrino suppression, mainly at low densities, in matter with trapped neutrinos. It is shown that an hybrid protoneutron star will not evolve to a low mass blackhole if the magnetic field is strong enough and the magnetic field does not decay. However, the decay of the magnetic field after cooling may give rise to the formation of a low mass blackhole.Comment: 17 pages, 10 figures, 3 tables, submitted to Phys. Rev.

Fuzzy Logic Controller of Five Levels Active Power Filter

AbstractThis paper presents five-level inverter as a shunt active power filter (SAPF) to compensate reactive power and suppresses harmonics drawn from a diode rectifier supplying RL load under distorted voltage conditions. The harmonic current extraction is based on the use of self tuning filter (STF) and fuzzy logic controller employed to control harmonic current and inverter DC voltage. The aim of the present work is to obtain a perfect compensation by extracting accurate harmonic currents to improve the performances of the five-levels active power filters.The proposed scheme is validated by computer simulation using MATLAB Fuzzy Logic Toolbox in order to show the effectiveness and ability of this method. The results have demonstrated that the proposed shunt active power filter with STF and Fuzzy Logic Controller (FLC) have produced a sinusoidal supply current with low harmonic distortion and in phase with the line voltage

LA GRIPPE A H1N1 : ACTUALITES

Influenza is a seasonal viral infection associated with significant morbidity and mortality. In 2009, a novel H1N1 influenza A virus emerged and has been classified as a pandemic. In contrast to seasonal influenza, severe disease from pandemic H1N1 seems concentrated in older children and young adults, with almost no cases reported in patients older than 60 yrs. Although patients with underlying cardiopulmonary disease remain at risk, most complications have occurred among previously healthy individuals, with obesity and respiratory disease as the strongest risk factors. Pulmonary complications are common. Primary influenza pneumonia occurs most commonly in adults and may progress rapidly to acute lung injury requiring mechanical ventilation. Secondary bacterial infection is more common in children. Staphylococcus aureus, including methicillin-resistant strains, is an important cause of secondary bacterial pneumonia with a high mortality rate. Treatment of pneumonia should include empirical coverage for this pathogen. Neuromuscular and cardiac complications are unusual but may occur.Le virus de la grippe saisonnière peut être associé à une morbidité voire une mortalité significative. Le nouveau réassortant H1N1 est responsable d’une pandémie en 2009. Contrairement à la grippe saisonnière, des complications sévères sont survenues chez les enfants et les adultes âgés de moins de 60 ans, sans maladies sous jacentes. Certaines pathologies augmentent par ailleurs le risque de complications graves notamment l’obésité, les maladies cardio-réspiratoires et les femmes enceintes. La pneumonie virale est une complication redoutable évoluant rapidement vers la détresse respiratoire aigue nécessitant une ventilation mécanique. La surinfection pulmonaire par le staphylocoque résistant à la méthicilline est possible, surtout chez l’enfant. D’autres complication sont possibles notamment neuromusculaires et cardiaque

Segmentation d'images ultrasonores

- Dans cette étude nous nous intéressons à la segmentation d'images ultrasonores. Nous développons une méthode de segmentation utilisant, d'une façon originale, le modèle de régions actives géodésiques. Cette approche tient compte à la fois des informations contours et régions. Nous exploitons les propriétés statistiques de ces informations. Pour cela l'information région est approchée par un modèle de distribution de niveaux de gris de la région. La recherche des contours est faite par la méthode des ensembles de niveaux à partir d'une courbe initiale. Nous avons testé notre algorithme sur des images ultrasonores réelles, images échotomographiques veineuses in vivo présentant un thrombus que nous cherchons à isoler. Les résultats expérimentaux obtenus illustrent bien les bonnes performances de notre algorithme pour détecter et localiser le thrombus, et montrent aussi que notre méthode est bien adaptée à la segmentation des images ultrasonores

Low doses of a neonicotinoid insecticide modify pheromone response thresholds of central but not peripheral olfactory neurons in a pest insect

Insect pest management relies mainly on neurotoxic insecticides, including neonicotinoids, leaving residues in the environment. There is now evidence that low doses of insecticides can have positive effects on pest insects by enhancing various life traits. Because pest insects often rely on sex pheromones for reproduction, and olfactory synaptic transmission is cholinergic, neonicotinoid residues could modify chemical communication. We recently showed that treatments with different sublethal doses of clothianidin could either enhance or decrease behavioural sex pheromone responses in the male moth, Agrotis ipsilon. We investigated now effects of the behaviourally active clothianidin doses on the sensitivity of the peripheral and central olfactory system. We show with extracellular recordings that both tested clothianidin doses do not influence pheromone responses in olfactory receptor neurons. Similarly, in vivo optical imaging does not reveal any changes in glomerular response intensities to the sex pheromone after clothianidin treatments. The sensitivity of intracellularly recorded antennal lobe output neurons, however, is upregulated by a lethal dose 20 times and downregulated by a dose 10 times lower than the lethal dose 0. This correlates with the changes of behavioural responses after clothianidin treatment and suggests the antennal lobe as neural substrate involved in clothianidin-induced behavioural changes