Répartition des glossines au Cameroun français (1953)

Aucun résumé disponible

A model for gelation with explicit solvent effects: Structure and dynamics

We study a two-component model for gelation consisting of $f$-functional monomers (the gel) and inert particles (the solvent). After equilibration as a simple liquid, the gel particles are gradually crosslinked to each other until the desired number of crosslinks has been attained. At a critical crosslink density the largest gel cluster percolates and an amorphous solid forms. This percolation process is different from ordinary lattice or continuum percolation of a single species in the sense that the critical exponents are new. As the crosslink density $p$ approaches its critical value $p_c$, the shear viscosity diverges: $\eta(p)\sim (p_c-p)^{-s}$ with $s$ a nonuniversal concentration-dependent exponent.Comment: 6 pages, 9 figure

Continuous cell lines and immune ascitic fluid pools in arbovirus detection

Pour la recherche et l'isolement des arbovirus, des expérimentations successives nous ont amenés à utiliser, parmi les lignées de cellules en culture continue dont l'utilisation est préconisée par l'OMS, les deux systèmes cellulaires MOS61 (cellules de #Aedes pseudoscutellaris$) et Vero. La détection des virus dans les sytèmes cellulaires est réalisée à l'aide de 7 pools de 10 ascites hyperimmunes polyvalentes. Cette technique permet la mise en évidence de 70 sur 80 arbovirus transmis par les moustiques en Afrique, et permet de détecter très facilement les associations d'arbovirus grâce aux ascites immunes monospécifiques ou monoclonales (dengue-1-2-3-4 et fièvre jaune). (Résumé d'auteur

Caractères cliniques et épidémiologiques de la dengue 2 au Sénégal

Les auteurs rappellent les faits historiques, cliniques et épidémiologiques concernant l'infection par les virus de la dengue en Afrique. Ils énumèrent les lieux, les hôtes et les circonstances de l'isolement de différentes souches africaines et rappellent le cycle sauvage du virus dengue 2 au Sénégal. L'isolement de deux souches humaines, pendant l'épizootie de 1990, est en faveur d'un cycle selvatique. Il s'agit en effet des premiers cas humains concomitants d'une épizootie au Sénégal. Les observations cliniques de ces deux cas sont celles d'une arbovirose mineure, sans syndrome de choc ni manifestations hémorragiques, soulignant la pathogénicité atténuée du virus dengue 2 au Sénégal comme dans les autres pays d'Afrique. De récents travaux d'épidémiologie moléculaire ont mis en évidence des caractères génotypiques particuliers de certaines souches africaines par rapport à celles rencontrées dans les régions Pacifique ou Caraïbes. (Résumé d'auteur

Ecology of tick as potentiel vectors of Crimean-Congo hemorrhagic fever virus in Senegal : epidemiological implications

Au moins trente espèces de tiques, provenant de 7 genres, ont été trouvées infectées du virus de la fièvre hémorragique de Crimée Congo. A cette liste, nous ajoutons #Rhipicephalus guilhoni. En Afrique subsaharienne, 17 espèces de tiques ont été reconnues en tant que vecteur de la maladie, dont 12 sont présents en Sénégambie et Mauritanie. Ont été étudiées les cinq plus importantes espèces dans la transmission du virus CCHF au Sénégal : #Amblyomma variegatum, #Hyalomma impeltatum, #Hyalomma marginatum rufipes, #Hyalomma truncatum$, et #Rhipicephalus guilhoni

O adsorption and incipient oxidation of the Mg(0001) surface

First principles density functional calculations are used to study the early oxidation stages of the Mg(0001) surface for oxygen coverages 1/16 <= Theta <= 3 monolayers. It is found that at very low coverages O is incorporated below the topmost Mg layer in tetrahedral sites. At higher oxygen-load the binding in on-surface sites is increased but at one monolayer coverage the on-surface binding is still about 60 meV weaker than for subsurface sites. The subsurface octahedral sites are found to be unfavorable compared to subsurface tetrahedral sites and to on-surface sites. At higher coverages oxygen adsorbs both under the surface and up. Our calculations predict island formation and clustering of incorporated and adsorbed oxygen in agreement with previous calculations. The calculated configurations are compared with the angle-scanned x-ray photoelectron diffraction experiment to determine the geometrical structure of the oxidized Mg(0001) surface.Comment: 10 pages, 5 figure

A New Finite-lattice study of the Massive Schwinger Model

A new finite lattice calculation of the low lying bound state energies in the massive Schwinger model is presented, using a Hamiltonian lattice formulation. The results are compared with recent analytic series calculations in the low mass limit, and with a new higher order non-relativistic series which we calculate for the high mass limit. The results are generally in good agreement with these series predictions, and also with recent calculations by light cone and related techniques

Resonant Tunnelling Diodes for Next Generation THz Systems

Resonant tunnelling diodes (RTDs) are a strong candidate for future wireless communications in the THz spectrum (sub-millimetre waves), offering compact, roomtemperature operation with the potential to exceed the bit transfer rate mandated by the 12G-SDI standard, using a single wireless link. A free-space RTD emitter operating at 353GHz is described. The fabrication process consists of a dual-pass I-line photolithography &amp; etch technique using an air bridge, allowing low resistivity ohmic contacts, and accurate control of desired device area. With extrinsic circuit elements taken into account, the intrinsic semiconductor efficiency is analysed to investigate structural improvements for radiative efficiency. Such optimised structures are presented, and then characterised after being epitaxially grown with commercially viable metal-organic vapour phase epitaxy (MOVPE) reactors. A combination of low temperature photoluminescence spectroscopy, X-Ray diffractometry, and transmission electron microscopy attest the quality of the new material. We end with a suggestion for the next steps to exceed technological readiness levels of 8, and use monolithic RTD emitters as components in new systems

Prolonged enoxaparin therapy compared with standard-of-care antithrombotic therapy in opiate-treated patients undergoing primary percutaneous coronary intervention

A novel enoxaparin regimen consisting of intra-arterial bolus (0.75 mg/kg) followed by intravenous infusion (0.75 mg/kg/6 hours) has been developed as a possible solution to the delayed absorption of oral P2Y12 inhibitors in opiate-treated ST-elevation myocardial infarction (STEMI) patients undergoing primary angioplasty. We aimed to study the feasibility of this regimen as an alternative to standard-of-care treatment (SOC) with unfractionated heparin ± glycoprotein IIb/IIIa antagonist (GPI). One hundred opiate-treated patients presenting with STEMI and accepted for primary angioplasty were randomized (1:1) to either enoxaparin or SOC. Fifty patients were allocated enoxaparin (median age 61, 40% females) and 49 allocated SOC (median age 62, 22% females). One developed stroke before angiography and was withdrawn. One SOC patient had a gastrointestinal bleed resulting in 1 g drop in hemoglobin and early cessation of GPI infusion. Two enoxaparin patients had transient minor bleeding: one transient gingival bleed and one episode of coffee ground vomit with no hemoglobin drop or hemodynamic instability. Two SOC and no enoxaparin group patients had acute stent thrombosis. These preliminary data support further study of this novel 6-hour enoxaparin regimen in opiate-treated PPCI patients