IPN : l’émergence des détecteurs à semi-conducteurs

Au début des années 1960, l’arrivée de nouveaux détecteurs de particules à base de semi-conducteurs dans les laboratoires a profondément bouleversé la conception des expériences et considérablement enrichi les résultats obtenus. L’influence d’une telle avancée technologique sur les recherches menées au laboratoire de physique nucléaire d’Orsay est analysée dans cet article.In the early sixties, new detectors, based upon semi-conductors appeared in the laboratories. At the Orsay “Laboratoire de physique nucléaire” as in the other laboratories, he availability of these new devices deeply modified the conception of experiments and considerably enriched their results. The influence of such a technological break through on fundamental research is analyzed in this paper

Etude de detecteurs nucleaires minces, passives et implantes, realises a partir de silicium epitaxique : applications aux ions lourds et au rayonnment synchrotron

CNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueSIGLEFRFranc

Ecological differentiation of Mediterranean endemic plants

International audienceA striking feature of the Mediterranean flora concerns the high rates of narrow endemism within many regions. The prevailing paradigm for the evolution of such endemism relies on an important role of geographic isolation and allopatric speciation. Until recently there has been little work on the precise ecological differences among endemic plants and their congeners in the Mediterranean region and the potential role of ecological specialisation in isolation and speciation. This paper has two objectives. First, we evaluate general ecological differences among endemic and widespread congeners in the flora of the western Mediterranean. The results and review of the literature attest to consistent patterns of ecological differentiation among endemic species and their snore widespread congeners. Second, we present results of a detailed study of morphological, molecular and ecological differentiation in a group of spring-flowering Mediterranean Cyclamen species. This study illustrates how differentiation in geographically peripheral and ecologically marginal populations may contribute to the diversification of endemic species whose contemporary distributions are disjunct from con-generic species

Wake vortex detection, prediction and decision support tools in SESAR program

airports, surface operation on the runway is the limiting factor for the overall throughput; specifically the fixed and overly conservative ICAO wake turbulence separation minima. The wake turbulence hazardous flows can dissipate quicker because of decay due to air turbulence or be transported out of the way on oncoming traffic by cross-wind, yet wake turbulence separation minima do not take into account wind conditions. Indeed, for safety reasons, most airports assume a worst-case scenario and use conservative separations; the interval between aircraft taking off or landing therefore often amounts to several minutes. However, with the aid of accurate wind data and precise measurements of wake vortex by radar sensors, more efficient intervals can be set, particularly when weather conditions are stable. Depending on traffic volume, these adjustments can generate capacity gains, which have major commercial benefits. This paper presents the developments of a wake turbulence system supporting increased throughput as part of the European ATM research program SESAR. This wake turbulence system is designed to, punctually or permanently, reduce landing and departure wake turbulence separations, thus increasing the runway throughput in such a way that arrival demand peaks and departure delays are safety absorbed. This global objective is by deploying radar sensors to deliver real-time position and strength information of the wake vortices and to assess wind conditions including ambient air turbulence via Eddy Dissipation Rate (EDR). To further address the optimization of throughput, two extensions for the use of wake turbulence system are considered for the terminal area and the runway rollout. These extensions connect the ground system with the aircraft to maximize benefits. The first application is the optimization of aircraft sequence via point-merge procedure, which is part of interval management operational improvement. The second application relates to the optimization of runway exit based on assessment of runway condition and aircraft-based braking capability to select the best runway exit for both the aircraft objectives and the runway throughput

An In Vivo and In Vitro Model of Plasmodium falciparum Rosetting and Autoagglutination Mediated by varO, a Group A var Gene Encoding a Frequent Serotype▿

In the Saimiri sciureus monkey, erythrocytes infected with the varO antigenic variant of the Plasmodium falciparum Palo Alto 89F5 clone bind uninfected red blood cells (rosetting), form autoagglutinates, and have a high multiplication rate, three phenotypic characteristics that are associated with severe malaria in human patients. We report here that varO parasites express a var gene having the characteristics of group A var genes, and we show that the varO Duffy binding-like 1α1 (DBL1α1) domain is implicated in the rosetting of both S. sciureus and human erythrocytes. The soluble varO N-terminal sequence (NTS)-DBL1α1 recombinant domain, produced in a baculovirus-insect cell system, induced high titers of antibodies that reacted with varO-infected red blood cells and disrupted varO rosettes. varO parasites were culture adapted in vitro using human erythrocytes. They formed rosettes and autoagglutinates, and they had the same surface serotype and expressed the same varO gene as the monkey-propagated parasites. To develop an in vitro model with highly homogeneous varO parasites, rosette purification was combined with positive selection by panning with a varO NTS-DBL1α1-specific mouse monoclonal antibody. The single-variant, clonal parasites were used to analyze seroprevalence for varO at the village level in a setting where malaria is holoendemic (Dielmo, Senegal). We found 93.6% (95% confidence interval, 89.7 to 96.4%) seroprevalence for varO surface-reacting antibodies and 86.7% (95% confidence interval, 82.8 to 91.6%) seroprevalence for the recombinant NTS-DBL1α1 domain, and virtually all permanent residents had seroconverted by the age of 5 years. These data imply that the varO model is a relevant in vivo and in vitro model for rosetting and autoagglutination that can be used for rational development of vaccine candidates and therapeutic strategies aimed at preventing malaria pathology

RAGE inhibition reduces acute lung injury in mice

International audienceThe receptor for advanced glycation end-products (RAGE) is involved in inflammatory response during acute respiratory distress syndrome (ARDS). Growing body of evidence support strategies of RAGE inhibition in experimental lung injury, but its modalities and effects remain underinvestigated. Anesthetised C57BL/6JRj mice were divided in four groups; three of them underwent orotracheal instillation of acid and were treated with anti-RAGE monoclonal antibody (mAb) or recombinant soluble RAGE (sRAGE), acting as a decoy receptor. The fourth group served as a control. Lung injury was assessed by the analysis of blood gases, alveolar permeability, histology, AFC, and cytokines. Lung expression and distribution epithelial channels ENaC, Na,K-ATPase, and aquaporin (AQP)−5 were assessed. Treatment with either anti-RAGE mAb or sRAGE improved lung injury, arterial oxygenation and decreased alveolar inflammation in acid-injured animals. Anti-RAGE therapies were associated with restored AFC and increased lung expression of AQP-5 in alveolar cell. Blocking RAGE had potential therapeutic effects in a translational mouse model of ARDS, possibly through a decrease in alveolar type 1 epithelial cell injury as shown by restored AFC and lung AQP-5 expression. Further mechanistic studies are warranted to describe intracellular pathways that may control such effects of RAGE on lung epithelial injury and repair. Acute respiratory distress syndrome (ARDS) is a syndrome of diffuse inflammatory lung injury with increased pulmonary oedema and the rapid onset of hypoxemic respiratory failure 1. ARDS is still undertreated 2 , with high mortality and few effective therapies 3-5. RAGE is a membrane receptor that is expressed in alveolar type (AT)-1 epithelial cells of the lung and a marker of epithelial injury 6. There are many RAGE ligands, including high-mobility group box 1 protein (HMGB1), advanced glycation end-products (AGEs) and S100 protein 7, 8. RAGE controls a variety of cellular processes such as cell proliferation and migration, inflammation, apoptosis and microtubule stabilization 9. Its main soluble forms, referred to as soluble RAGE (sRAGE), include the extra-cellular domain of membrane RAGE (mRAGE) which is cleaved by proteinases and endogenous secretory RAGE (esRAGE, produced after alternative splicing) 10. In clinical ARDS, sRAGE has good diagnostic value and is associated with lung injury severity, impaired alveolar fluid clearance (AFC) and prognosis 6, 11-13. Impaired AFC is a major feature of ARDS that contributes to mortality 14. The main mechanism responsible for the resolution of alveolar oedema is ion transport across the alveolar epithelium, primarily through epithe-lial sodium (ENaC), Na,K-ATPase and aquaporin (AQP)-5 channels, thus creating a local osmotic gradient to reabsorb the water fraction of the oedema fluid from the airspaces of the lungs 15-17. Recent data support an effect of RAGE activation on ENaC activity in cultured AT-1 cells 18. However, in contrast to the situation in mice, the clearance of alveolar fluid after birth in humans may not critically depend on ENaC, at least in part because of greater reliance on other epithelial channels 15. The modulation of RAGE may reduce inflammatory responses in several models 19. Intratracheal administration of HMGB1 induced lung injury in mice and the pathological effects of intratracheal lipopolysaccharide (LPS) were partially ameliorated by systemic administration of anti-HMGB1 antibodies 8 , thereby implicating pattern-recognition receptors such as RAGE or toll-like receptors in the pathogenesis of ARDS. Experimental murine pulmonary ischemia followed by reperfusion caused lung injury that was ameliorated in mice treated with sRAGE and in RAGE −/− mice 20. Using a mouse model of lun

Outbreak of Oropouche Virus in French Guiana

International audienceOropouche fever is a zoonotic dengue-like syndrome caused by Oropouche virus. In August–September 2020, dengue-like syndrome developed in 41 patients in a remote rainforest village in French Guiana. By PCR or microneutralization, 23 (82.1%) of 28 tested patients were positive for Oropouche virus, documenting its emergence in French Guiana