Journal of Next-Generation Research 5.0
Not a member yet
7559 research outputs found
Sort by
Centres et périphéries : le cas des littératures arabes contemporaines dans l'océan Indien
No full textInternational audienc
Couplage aérosols-microphysique pour la simulation des cyclones tropicaux : Cas du cyclone Dumile (2013)
No full textIntensity forecast of tropical cyclones is a major scientific issue. Among many factors, the impact of cloud microphysics and aerosols on intensity variations has been recently underlined. This issue motivated the evaluation of the 2-moment microphysical scheme LIMA in a tropical context and the development of a coupling with the aerosol scheme ORILAM into the atmospheric model Meso-NH. The interest of this numerical development is to represent the emission of sea salt aerosols depending on cyclonic winds and oceanic parameters. The application of this aerosols-microphysics coupling to the simulation of tropical cyclone Dumile (2013) shows that the coupled model tends to improve the representation of the intensity, the track, the microphysical structure of the tropical cyclone and the associated precipitation, when comparing with observations. The secondary production of ice crystals is also an active research topic in cloud microphysics. A parameterization of the collisional ice break-up process is thus implemented into the microphysical scheme LIMA. The impact of this process has been analyzed on a mid-latitude storm and on tropical cyclone Dumile. Both case studies display similar results regarding this process: an increase of ice crystals concentration and mass, and a decrease of precipitation. The continuation of this work could allow to determine if this process of secondary formation could improve the cirrus modelling in tropical cyclones.La prévision de l'intensité des cyclones tropicaux est aujourd'hui un enjeu scientifique majeur. Parmi de nombreux facteurs multi-échelle, l'impact de la microphysique nuageuse et des aérosols sur les variations d'intensité a été récemment mis en évidence. Cette problématique a motivé l'évaluation du schéma microphysique à 2-moments LIMA en milieu tropical et le développement d'un couplage avec le schéma d'aérosols ORILAM au sein du modèle atmosphérique Meso-NH. L'intérêt de ce développement numérique est d'inclure l'émission des aérosols marins en fonction des vents cycloniques et des paramètres océaniques. L'application de ce couplage aérosols-microphysique à la simulation du cyclone tropical Dumile (2013) montre que le modèle couplé tend à améliorer la représentation de l'intensité, la trajectoire, la structure microphysique du cyclone tropical et les précipitations associées, en comparaison avec les observations. La production secondaire des cristaux de glace est également un thème de recherche actif en microphysique nuageuse. Ainsi, une paramétrisation du processus de rupture collisionnelle de la glace a été implémentée dans le schéma microphysique LIMA. L'impact de ce processus a été testé sur le développement d'un orage des moyennes latitudes et sur le cyclone tropical Dumile. Les deux cas d'étude ont des réponses similaires vis-à-vis de ce processus : une augmentation de la concentration et de la masse des cristaux de glace et une diminution des cumuls de précipitations. La poursuite de ces travaux pourrait permettre de déterminer si ce processus de formation secondaire peut améliorer la modélisation de la couverture cirriforme des cyclones tropicaux
Assessment of the role of ageing and light availability in leaf mortality in mango tree
No full textAssessment of the role of ageing and light availability in leaf mortality in mango tree. The 30th International Horticultural Congres
Der Träger im Kolonialismus. Fotoausstellung
No full textDie Fotoausstellung ist als Wanderausstellung gedacht und wir ab Oktober 2018 für ca ein Jahr am Institut für Afrikanistik der Universität Wien gezeigt werden.Exposition photographiqueEs handelt sich um eine Fotoausstellung, die die Geschichte des kolonialen Trägerwesens quer durch verschiedene Kontinente zu dokumentieren versucht. Gezeigt wurde diese Ausstellung zunächst auf der Insel La Réunion, jetzt an der Universität Wien
Sustainable management of root-knot nematodes in horticultural crops by modeling and optimizing resistance gene deployment
No full textInternational audienceRoot-knot nematodes (RKNs) of the genus Meloidogyne are soil-borne, little mobile, polyphagous pests which threaten important sheltered crops such as vegetables or small fruits. They attack plant roots to feed and reproduce and have a major impact on crop yield. Most eco-friendly plant protection strategies are based on the use of resistant crops. Resistance is usually associated with a hypersensitivity reaction (HR), a rapid and localized cell death in the infected plant in response to a pathogenic attack. In the family Solanaceae, there are two major resistance genes (R genes) with different modes of action : an early HR when the nematode enters in the root system and a late HR when the nematode creates its feeding site. The emergence of virulent nematode variants, which are adapted to the resistance, challenges the durability of such methods. Because virulent root-knot nematodes exhibit a reduced fitness on susceptible crops, combining both resistant and susceptible plants can help increase the efficacy and sustainability of resistance-based nematode control. We carried out a preliminary study to investigate the best rotations of susceptible and resistant cultivars over cropping seasons in terms of yield and resistance durability. The resistance considered was associated with early HR. For this purpose, we developed a semi discrete model describing the plant root growth and nematode population dynamics within and between cropping season, including the plant nematode interactions. Our aim in this study is to implement and compare the action of both R genes. We will first compare the optimal deployment strategies of resistant crops for both R genes. Then we will determine the best rotations based on both resistant cultivars
Optimal control of averaged state of a parabolic equation with missing boundary condition
No full textInternational audienceWe consider the optimal control of general heat governed by an operator depend on an unknown parameter and with missing boundary condition. Using the notion of no-regret and low-regret control we prove that we can bring the average of the state of our model to a desired state. Then by means of Euler-Lagrange first order optimality condition, we expressed the optimal control in term of average of an appropriate adjoint state that we characterize by an optimality system. The main tools are the Lebesgue dominated convergence theorem and an appropriate Hilbert space endowed with a norm containing the average of the state
Protein local conformations at the light of a structural alphabet
No full textInternational audienceProtein structures are classically described in terms of secondary structures. Even if the regular secondary structures have relevant physical meaning, their recognition from atomic coordinates has some important limitations such as uncertainties in the assignment of boundaries of helical and β-strand regions. Further, on an average about 50% of all residues are assigned to an irregular state, i.e., the coil. Thus different research teams have focused on abstracting conformation of protein backbone in the localized short stretches. Using different geometric measures, local stretches in protein structures are clustered in a chosen number of states. A prototype representative of the local structures in each cluster is generally defined. These libraries of local structures prototypes are named as "structural alphabets". We have developed a structural alphabet, named Protein Blocks, not only to approximate the protein structure, but also to predict them from sequence [1,2]. Since its development, we and other teams have explored numerous new research fields using this structural alphabet. I will review here some of the most interesting applications: (i) the most efficient protein superimposition methods [3,4], (ii) new ways to analyze protein structures [2], and (iii) new tool for analysis of protein dynamics and allostery [5,6]
Analysing the Structural Effect of Point Mutations of Cytotoxic Necrotizing Factor 1 (CNF1) on Lu/BCAM Adhesion Glycoprotein Association
No full textInternational audienceCytotoxic Necrotizing Factor 1 (CNF1) was identified in 1983 as a protein toxin produced by certain pathogenic strains of Escherichia coli. Since then, numerous studies have investigated its particularities. For instance, it is associated with the single chain AB-toxin family, and can be divided into different functional and structural domains, e.g., catalytic and transmembrane domain and interaction sites. A few years ago, the identification of the Lutheran (Lu) adhesion glycoprotein/basal cell adhesion molecule (BCAM) as a cellular receptor for CNF1 provided new insights into the adhesion process of CNF1. Very recently, the Ig-like domain 2 of Lu/BCAM was confirmed as the main interaction site using protein-protein interaction and competition studies with various different mutants. Here, I present in silico approaches that precisely explain the impact of these mutations, leading to a better explanation of these experimental studies. These results can be used in the development of future antitoxin strategies
: Monitoring the impact of local management of natural resources on forest conservation in north-eastern Madagascar
No full textArticle publié en français (p.28-35), avec un résumé étendu en anglais (p.36-37), et 8 planches couleur hors-texte (p.70-77)International audienceThis study describes the use of PCA (Principal Components Analysis) and fuzzy logic methods to solve change detection problems and map land cover changes by using AdaBoost Neural Network-based algorithm. The aim is to study the impact on forest conservation of transferring the management of natural resources from national to local level, with a case-study in Didy area in North-Eastern Madagascar (Plates 1 and 2). The test site is located at the transition between humid forest and savanna and lower areas are occupied by rice fields.In this approach, the study makes the difference pixel by pixel of each pair of spectral bands acquired at two dates. After that, all images have been introduced as variables into the PCA process in order to reduce them to the first axes. Then, the fuzzy approach is applied over the first PCA components to highlight the pixels that show the changes. Finally, changes on image were classified so as to find all types of land cover changes. The application of this method was performed on Landsat 5 images (path = 158, row = 073) acquired in 1994, 2001 and 2009, to verify the impact of the management of natural resources by the local community and its impacts on forest conservation. Images of 1994 and 2001 are used to study the changes before management of natural resources transfer projects. And images taken in 2001 and 2009 are processed for studying changes since this project launches. In this study, we considered only the first three components of PCA because they contain all change information (table 1). The first three PCA component histograms show that all pixels values are close to the normal distribution (Plate 3). So, the use of fuzzy membership function proposed by Gong (1993) is well justified. Plate 4 shows the map of changes by PCA and fuzzy set theory (a): between 1994 and 2001; (b): between 1994 and 2001. Then, the changes in Plate 4 were classified using an Adaboost Neural Network-based algorithm.To verify the effectiveness of management transfer at local level on forest conservation, three vegetation classes were analyzed: crops on slash and burn areas, natural forest and forest regrowth. Results from changes map are displayed at Plates 5 and 6. Statistics of changes have been computed (Table 2), excluding changes to clouds and shadows. Analysis of map and statistical results shows that after local communities manage natural resources, there was a decrease of the practice of slash and burn (‘tavy’) and a progressive dynamic from any other land cover classes to forest regrowth ('savoka'). Consequently, this study demonstrates that the transfer of natural resources management to the local community has a significant positive impact on forest conservation.Cette étude illustre l’utilisation de la méthode ACP (Analyse en Composantes Principales) combinée avec l’approche floue, pour décrire les changements de l’occupation du sol, et la classification des changements obtenue par l’algorithme du réseau de neurones artificiel AdaBoost. L’application de cette méthode qui a été effectuée sur des images satellitaires Landsat 5 acquises respectivement en 1994, 2001 et 2009 a aussi pour but de montrer l’impact du processus de transfert de la gestion des ressources naturelles aux communautés locales sur la conservation des forêts dans la commune rurale de Didy, région Alaotra-Mangoro, Madagascar. L’étude a été faite en utilisant des images prises avant et après la mise en place du processus des projets de transfert de gestion. Les résultats montrent que ce mode de gestion des ressources naturelles a un apport positif sur la conservation des forêt