442 research outputs found
Multi Sensor Data Fusion Architectures for Air Traffic Control Applications
Nowadays, the radar is no longer the sole technology which is able to ensure the surveillance of air traffic. The extensive deployment of satellite systems and air-to-ground data links leads to the emergence of complementary means and techniques on which a great deal of research and experiments have been carried out over the past ten years. In such an environment, the sensor data processing, which is a key element in any Air Traffic Control (ATC) centre, has been continuously upgraded so as to follow the sensor technology evolution and in the meantime improves the quality in term of continuity, integrity and accuracy criteria. This book chapter proposes a comprehensive description of the state of art and the roadmap for the future of the multi sensor data fusion architectures and techniques in use in ATC centres. The first part of the chapter describes the background of ATC centres, while the second part of the chapter points out various data fusion techniques. Multi radar data processing architecture is analysed and a brief definition of internal core tracking algorithms is given as well as a comparative benchmark based on their respective advantages and drawbacks. The third part of the chapter focuses on the most recent evolution that leads from a Multi Radar Tracking System to a Multi Sensor Tracking System. The last part of the chapter deals with the sensor data processing that will be put in operation in the next ten years. The main challenge will be to provide the same level of services in both surface and air surveillance areas in order to offer: ⢠highly accurate air and surface situation awareness to air traffic controllers, ⢠situational awareness via Traffic Information System â Broadcast (TIS-B) services to pilots and vehicle drivers, and ⢠new air and surface safety, capacity and efficiency applications to airports and airlines
A Model of Perinatal Ischemic Stroke in the Rat: 20 Years Already and What Lessons?
Neonatal hypoxia-ischemia (HI) and ischemia are a common cause of neonatal brain injury resulting in cerebral palsy with subsequent learning disabilities and epilepsy. Recent data suggest a higher incidence of focal ischemia-reperfusion located in the middle cerebral artery (MCA) territory in near-term and newborn babies. Pre-clinical studies in the field of cerebral palsy research used, and still today, the classical HI model in the P7 rat originally described by Rice et al. (1). At the end of the 90s, we designed a new model of focal ischemia in the P7 rat to explore the short and long-term pathophysiology of neonatal arterial ischemic stroke, particularly the phenomenon of reperfusion injury and its sequelae (reported in 1998). Cerebral blood-flow and cell death/damage correlates have been fully characterized. Pharmacologic manipulations have been applied to the model to test therapeutic targets. The model has proven useful for the study of seizure occurrence, a clinical hallmark for neonatal ischemia in babies. Main pre-clinical findings obtained within these 20 last years are discussed associated to clinical pattern of neonatal brain damage
Effets du monoxyde d'azote inhalé sur le cerveau en développement chez le raton
L inhalation de monoxyde d azote (NO) est l une des thérapies les plus utilisées en réanimation néonatale. Cependant, peu de données sont disponibles sur l impact de l inhalation de NO sur le développement cérébral et le devenir des enfants prématurés. Nous avons étudié l impact du monoxyde d azote inhalé (iNO) sur le cerveau en développement chez le rongeur. Des portées et leur mère sont placés sous 5 à 20 ppm de NO de la naissance (P0) jusqu au 7ème jour de vie postnatal (P7). Les animaux exposés au NO présentent une augmentation transitoire de l angiogenèse et de la myélinisation, sans incidence sur les fonctions cognitives à l âge adulte. L exposition au NO est associée à une prolifération d oligodendrocytes immatures et à une maturation anticipée des formes myélinisantes. Les rôles du NO endogène et du couple VEGF/VEGFR2 dans ces effets ont été évalués via l injection d antagonistes : LNAME pour inhiber les NOS, SU-5416 comme antagoniste du VEGFR2. Dans les deux cas, l inhalation de NO corrige les anomalies de myélinisation et d angiogenèse induites par ces inhibiteurs. Nous avons soumis des ratons à une agression excitotoxique par injection intracérébrale d agonistes du glutamate. A P10 les rats exposés au iNO avant l injection présentent des lésions moins importantes ; ainsi qu un diminution de densité des microglies activées et des astrocytes. Cet effet neuroprotecteur est associé à une régulation de sous-unités des récepteurs au glutamate dès P5. Cet effet transcriptionnel semble lié à la modulation de la signalisation pCREB/Akt. Les effets à distance du iNO sont liés à un transport réversible endovasculaire du NO. In fine, du NO est delivré à la cellule et les concentrations intracellaires de cGMP augmentent d un facteur 5. Plusieurs facteurs de transcription sont régulés : PDGFR-a, Sema3F, les sous-unités des récepteurs au glutamate, Thrombospondine-1. Cette dernière est un antagoniste naturel de la signalisation NO-cGMP. L injection de ABT-510, agoniste de TSP-1, abolit les effets du iNO, confirmant l hypothèse que les effets à distance reposent sur la signalisation NO-Guanylate Cyclase soluble-cGMP. Au total, nous avons démontré que le iNO est transporté de manière réversible et delivré au cerveau en développement. Il y exerce un effet pro-angiogénique et pro-myélinisant, via une signalisation cGMP, régulée par la thrombospondine-1. Plus encore, l exposition prophylactique au iNO diminue l impact d une agression excitotoxique. Ce qui augure de propriétés neuroprotectrices prometteuses en néonatalogie, et au delà.Inhaled nitric oxide (iNO) is one of the most promising therapies used in neonates, but littlei known about its effect on the developing brain. We explored the effects of iNO on developing brain in rodent pups, and pathway involved in iNO remote effects. Rat pups and their mothers were placed in a chamber containing 5 to 20 ppm of NO for 7 days after birth. Extensive serum analysis, immunochemistry, RT-PCR analysis, were performed Neonatal exposure to iNO was associated with a transient increase in central nervous system myelination and angiogenesis in rats, without any behavioral consequences in adulthood. Exposure to iNO was associated with a proliferative effect on immature oligodendrocytes and a subsequent promaturational effect. The role of endogenous NO in myelination was investigated in animals treated with the nitric oxides synthase inhibitor N-nitro-L- arginine methyl ester (L-NAME) in the neonatal period ; this led to protracted myelination defects and subsequent behavioral deficits in adulthood. These effects were reversed by rescuing L-NAME-treated animals with iNO. We challenged animals with intracranial injection of glutamate agonists. At P10, rat pups exposed to iNO exhibited a significant decrease of lesion size in both the white matter and cortical plate compared to controls. Microglia activation and astrogliosis were found significantly decreased in NO-exposed animals. This neuroprotective effect was associated with a significantdecrease of several glutamate receptor subunits expression at P5. iNO was associated with an early(P1) downregulation of pCREB/pAkt expression and induced an increase in pAkt proteinconcentration in response to excitotoxic challenge (P7) Those effects were related to a release of NOto the cells, and a rise of cGMP intracellular concentration. Several transcription factor wereregulated, namely PDGFR-a, Sema3F, TSP-1, glutamate receptors subunits, Thrombospondin-1. Thelatter was responsible for NO pathway regulation, and injection of TSP-1 agonist (AbT-510) abolishediNO remote effects. iNO remote effects are not associated VEGF concentration increase nor VEGFRstimulation, as VEGF-R antagonist SU54-16 failed to abolish iNO effects on angiogenesis andmyelination. Moreover iNO reverses severe myelination and angiogenesis defects induced by this SU-5416. Thus, we demonstrate transport and considerable remote effect of iNO on angiogenesis andmyelination in rodents. Those effects are related to an enhancement of cGMP pathway, regulated byTSP-1, and transcriptional effects. Moreover we described and investigated the neuroprotectiveeffect of iNO in neonatal excitotoxic-induced brain damage. These data point to potential newavenues for neuroprotection in human perinatal brain damage.PARIS5-Bibliotheque electronique (751069902) / SudocSudocFranceF
Air Traffic Control Tracking Systems Performance Impacts with New Surveillance Technology Sensors
Nowadays, the radar is no longer the only technology able to ensure the surveillance of air traffic. The extensive deployment of satellite systems and air-to-ground data links lead to the emergence of other means and techniques on which a great deal of research and experiments have been carried out over the past ten years. In such an environment, the sensor data processing, which is a key element of an Air Traffic Control center, has been continuously upgraded so as to follow the sensor technology evolution and, at the same time, ensure a more efficient tracking continuity, integrity and accuracy. In this book chapter we propose to measure the impacts of the use of these new technology sensors in the tracking systems currently used for Air Traffic Control applications. The first part of the chapter describes the background of new-technology sensors that are currently used by sensor data processing systems. In addition, a brief definition of internal core tracking algorithms used in sensor data processing components, is given as well as a comparison between their respective advantages and drawbacks. The second part of the chapter focuses on the Multi Sensor Tracking System performance requirements. Investigation regarding the use of Automatic Dependent Surveillance â Broadcast reports and/or with a multi radars configuration, are conducted. The third part deals with the impacts of the âvirtual radarâ or âradar-likeâ approaches that can be used with ADS-B sensors, on the multi sensor tracking system performance. The fourth and last part of the chapter discusses the impacts of sensor data processing performance on sub-sequent safety nets functions that are: ⢠Short term conflict alerts (STCA), ⢠Minimum Safe Altitude Warnings (MSAW), and ⢠Area Proximity Warnings (APW)
Pain, Parental Involvement, and Oxytocin in the Neonatal Intensive Care Unit
Preterm infants (PTI) typically experience many painful and stressful procedures or events during their first weeks of life in a neonatal intensive care unit, and these can profoundly impact subsequent brain development and function. Several protective interventions during this sensitive period stimulate the oxytocin system, reduce pain and stress, and improve brain development. This review provides an overview of the environmental risk factors experienced by PTI during hospitalization, with a focus on the effects of pain, and early maternal separation. We also describe the long-term adverse effects of the simultaneous experiences of pain and maternal separation, and the potential beneficial effects of maternal vocalizations, parental contact, and several related processes, which appear to be mediated by the oxytocin system
Knowledge Gaps and Emerging Research Areas in Intrauterine Growth Restriction-Associated Brain Injury
Intrauterine growth restriction (IUGR) is a complex global healthcare issue. Concerted research and clinical efforts have improved our knowledge of the neurodevelopmental sequelae of IUGR which has raised the profile of this complex problem. Nevertheless, there is still a lack of therapies to prevent the substantial rates of fetal demise or the constellation of permanent neurological deficits that arise from IUGR. The purpose of this article is to highlight the clinical and translational gaps in our knowledge that hamper our collective efforts to improve the neurological sequelae of IUGR. Also, we draw attention to cutting-edge tools and techniques that can provide novel insights into this disorder, and technologies that offer the potential for better drug design and delivery. We cover topics including: how we can improve our use of crib-side monitoring options, what we still need to know about inflammation in IUGR, the necessity for more human post-mortem studies, lessons from improved integrated histology-imaging analyses regarding the cell-specific nature of magnetic resonance imaging (MRI) signals, options to improve risk stratification with genomic analysis, and treatments mediated by nanoparticle delivery which are designed to modify specific cell functions
Supporting women farmers in a changing climate: five policy lessons
Policies, institutions and services to help farmers develop new approaches to deal with climate change will need to produce results for women farmers as well as men. This brief provides five policy lessons to support this process, based
on evidence from research in low- and middle- income countries and offers guidelines for crafting gender-responsive climate policies at global and national levels. This research was presented in March 2015 at a seminar in Paris on ‘Closing the gender gap in farming under climate change’, co-organized by the CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS), the International Social Science Council (ISSC) and Future Earth
Expression variation in connected recombinant populations of Arabidopsis thaliana highlights distinct transcriptome architectures
<p>Abstract</p> <p>Background</p> <p>Expression traits can vary quantitatively between individuals and have a complex inheritance. Identification of the genetics underlying transcript variation can help in the understanding of phenotypic variation due to genetic factors regulating transcript abundance and shed light into divergence patterns. So far, only a limited number of studies have addressed this subject in Arabidopsis, with contrasting results due to dissimilar statistical power. Here, we present the transcriptome architecture in leaf tissue of two RIL sets obtained from a connected-cross design involving 3 commonly used accessions. We also present the transcriptome architecture observed in developing seeds of a third independent cross.</p> <p>Results</p> <p>The utilisation of the novel R/eqtl package (which goal is to automatize and extend functions from the R/qtl package) allowed us to map 4,290 and 6,534 eQTLs in the Cvi-0 × Col-0 and Bur-0 × Col-0 recombinant populations respectively. In agreement with previous studies, we observed a larger phenotypic variance explained by eQTLs in linkage with the controlled gene (potentially <it>cis</it>-acting), compared to distant loci (acting necessarily indirectly or in <it>trans</it>). Distant eQTLs hotspots were essentially not conserved between crosses, but instead, cross-specific. Accounting for confounding factors using a probabilistic approach (VBQTL) increased the mapping resolution and the number of significant associations. Moreover, using local eQTLs obtained from this approach, we detected evidence for a directional allelic effect in genes with related function, where significantly more eQTLs than expected by chance were up-regulated from one of the accessions. Primary experimental data, analysis parameters, eQTL results and visualisation of LOD score curves presented here are stored and accessible through the QTLstore service database <url>http://qtlstore.versailles.inra.fr/</url>.</p> <p>Conclusions</p> <p>Our results demonstrate the extensive diversity and moderately conserved eQTL landscape between crosses and validate the utilisation of expression traits to explore for candidates behind phenotypic variation among accessions. Furthermore, this stresses the need for a wider spectrum of diversity to fully understand expression trait variation within a species.</p
Melatonin Promotes Oligodendroglial Maturation of Injured White Matter in Neonatal Rats
OBJECTIVE:To investigate the effects of melatonin treatment in a rat model of white matter damage (WMD) in the developing brain. Additionally, we aim to delineate the cellular mechanisms of melatonin effect on the oligodendroglial cell lineage. METHODS:A unilateral ligation of the uterine artery in pregnant rat at the embryonic day 17 induces fetal hypoxia and subsequent growth restriction (GR) in neonatal pups. GR and control pups received a daily intra-peritoneal injection of melatonin from birth to post-natal day (P) 3. RESULTS:Melatonin administration was associated with a dramatic decrease in microglial activation and astroglial reaction compared to untreated GR pups. At P14, melatonin prevented white matter myelination defects with an increased number of mature oligodendrocytes (APC-immunoreactive) in treated GR pups. Conversely, melatonin was not found to be associated with an increased density of total oligodendrocytes (Olig2-immunoreactive), suggesting that melatonin is able to promote oligodendrocyte maturation but not proliferation. These effects appear to be melatonin-receptor dependent and were reproduced in vitro. INTERPRETATION:These data suggest that melatonin has a strong protective effect on developing damaged white matter through decreased microglial activation and oligodendroglial maturation leading to a normalization of the myelination process. Consequently, melatonin should be a considered as an effective neuroprotective candidate not only in perinatal brain damage but also in inflammatory and demyelinating diseases observed in adults
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