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Expérimentation d'une démarche méthodologique explorant les ressorts du sensible dans l'analyse de la perception des changements de l'environnement : présentation de « l'enquête Gulliver »
No full textIl s'agit d'une présentation (résumée) d'une démarche pour recueillir l'analyse de données sur la perception de risques (submersion érosion) que j'ai appelée" Enquête Gulliver"à mi-chemin entre cartographie participative et méthode photo-élicitatio
Efficiency modeling and exploration of 64-bit ARM compute nodes for exascale
No full textInternational audienceThis paper investigates the use of 64-bit ARM cores to improve the processing efficiency of upcoming HPC systems. It describes a set of available tools, models and platforms, and their combination in an efficient methodology for the design space exploration of large manycore computing clusters. Experimentations and results using representative benchmarks allow to set an exploration approach to evaluate essential design options at micro-architectural level while scaling with a large number of cores. We then apply this methodology to examine the validity of SoC partitioning as an alternative to using large SoC designs based on coherent multi-SoC models and the proposed SoC Coherent Interconnect (SCI)
L'organisation de la justice pénale en Afrique occidentale française : le cas du Sénégal de 1887 à l'aube des indépendances (1887-1960)
No full textThe period going from 1887 to the independences (1960) allows us to approach the question of the justice in French West Africa by highlighting the transformation of rules and the exercise of the justice, as well as the meeting between the Western system and the local legal pluralism. In Senegal as in the other territories of the French West Africa, the legal and judicial evolution reveals the opposition between two trends: that of the assimilation and that of the adaptation. Within the framework of this confrontation, jurisdictions that are unknown in the mainland France are created in the colonies in order to remedy with the lack of staff and with the financial means of the jurisdictions. For these same reasons the collegiality remains very rare and the justice is often organized around only one judge who is in charge of the pursuit, the investigation and the judgement. The organisation of the native penal justice set up in 1903, practically meets with the will of keeping the native institutions. However, the desire of assimilation leads to achieve around it reforms which tend to weaken the native institutions.La période allant de 1887 aux indépendances (1960) permet d’aborder la question de la justice en Afrique occidentale française en mettant en évidence la transformation des règles et de l’exercice de la justice, ainsi que la rencontre entre le système occidental et le pluralisme juridique local. Au Sénégal, comme dans les autres territoires de l’Afrique occidentale française, l’évolution juridique et judiciaire révèle l’opposition de deux tendances : celle de l’assimilation et celle de l’adaptation. Dans le cadre de cette confrontation, des juridictions non connues en métropole sont créées dans les colonies afin de remédier à l’insuffisance de personnel et des moyens financiers des juridictions. Pour ces mêmes raisons, la collégialité demeure très rare et la justice est souvent organisée autour d’un seul juge qui prend en charge la poursuite, l’instruction et le jugement. L’organisation de la justice pénale indigène, mise en place en 1903, répond avec pragmatisme à la volonté de maintenir les institutions indigènes. Toutefois, le désir d’assimilation conduit à y réaliser des réformes qui tendent à affaiblir les institutions indigènes
The differential effects of prolonged exercise upon executive function and cerebral oxygenation
No full textInternational audienceThe acute-exercise effects upon cognitive functions are varied and dependent upon exercise duration and intensity, and the type of cognitive tasks assessed. The hypofrontality hypothesis assumes that prolonged exercise, at physiologically challenging intensities, is detrimental to executive functions due to cerebral perturbations (indicated by reduced prefrontal activity). The present study aimed to test this hypothesis by measuring oxygenation in prefrontal and motor regions using near-infrared spectroscopy during two executive tasks (flanker task and 2-back task) performed while cycling for 60 min at a very low intensity and an intensity above the ventilatory threshold. Findings revealed that, compared to very low intensity, physiologically challenging exercise (i) shortened reaction time in the flanker task, (ii) impaired performance in the 2-back task, and (iii) initially increased oxygenation in prefrontal, but not motor regions, which then became stable in both regions over time. Therefore, during prolonged exercise, not only is the intensity of exercise assessed important, but also the nature of the cognitive processes involved in the task. In contrast to the hypofrontality hypothesis, no inverse pattern of oxygenation between prefrontal and motor regions was observed, and prefrontal oxygenation was maintained over time. The present results go against the hypofrontality hypothesis. (C) 2017 Elsevier Inc. All rights reserved
Using Geomorphology to identify oases and prehistoric refugia in arid environments: an attempt to draw a typology of the superficial deposits characteristic of these spaces.La géomorphologie au service de l'identification des oasis et des refuges préhistoriques en milieux arides : essai de typologie des formations superficielles caractéristiques de ces espaces.
No full textInternational audiencePrehistoric refuges and oases are intrinsically defined and understood as local exceptions to a regional inhospitable environment. In arid lands, a part of this discrepancy is a consequence of natural factors, environmental and/or palaeoenvironmental, which renderedcertainplaces more hospitable for human activities than their surroundings such asmore favourable climatic contexts, the offset ofaridification by groundwater resources linked to hydrogeological settings, exogenous resources, etc. Prehistoric refuges and oases are thus specific environments which are very different from their surrounding regions and which played a role in the concentration of human activities. This implies a juxtaposition between two very different kinds of environment (desert and oasis). The borders between them moved over time according to complex socio-environmental evolutions. This interweaving and diachronic mobility of different environments gave birth to specific superficial deposits and erosion dynamics. A geomorphological typology of these features can be built. This kind of tool is an essential contribution to the description of prehistoric refuges and oases as spatial objects: it can facilitate the identification of ancient sites through field survey and through visual analysis of satellite imagery.After a description of the main types of natural oasis sites and a statement about classical criteria used to define oases and refugia in desert lands, this contribution aims to initiate a geomorphological definition of these spaces by producing a typology of the specific forms which are present within them. Built from data found in scientific literature or gathered from different study areas in the Saharo-Arabian region (Kharga basin in Egypt, Nefzaoua region in Tunisia, al Hajar Mountains in the United Arab Emirates),this typology is based on six classes of geomorphological features (or their remains), organized according to genetic criteria (accumulation/ablation, aeolian/waterborne/anthropogenic/combined). Some of them can be found in almost all of the oases and in many prehistoric refuges; others follow a less extensive spatial and temporal distribution as they are inherited from more punctual contexts and transition periods. The proposed typology is inevitably provisional as it needs to be enhanced through comparison with data from other sites and regions of the world.Les refuges préhistoriques et les oasis se définissent et se conçoivent par essence comme des exceptions locales à un environnement régional inhospitalier. En milieu aride, cette discordance s'explique en partie par des facteurs naturels, environnementaux et paléoenvironnementaux, qui rendent certains espaces plus propices à l'installation d'êtres humains : contexte climatique local plus favorable,configuration hydrogéologique à l'origine de ressources en eau compensant l'aridification, ressources allochtones, etc. Les refuges préhistoriques et les oasis correspondent donc à des environnements qui tranchent avec les régions qui les entourent et qui ont participé à la concentration des activités humaines. Il en découle une juxtaposition entre des types de milieux très différents (désertiquesd'un côté, oasiens de l'autre) et dont les limites fluctuent au fil du temps en fonction d'évolutions socio-environnementales complexes. De cette imbrication et de cette mobilité diachronique des différents milieuxsont nées des formations superficielles et des dynamiques d'érosion caractéristiques dont on peut établir une typologie géomorphologique. Un tel outil est essentiel pour décrire les espaces de refuges préhistoriques et d'oasis : il facilite l'identification de sitesanciens à partir de prospections de terrain et de travaux de photo-interprétation ou de télédétection sur images satellitaires.Après une description des grands types de géosites oasiens et un rappel des critères classiques de définition des oasis et des refuges en milieu désertique, cette communication visera à amorcer une définitiongéomorphologique de ces espaces parun essai de typologie des formes qu'on y observe. Construite à partir d'informations tirées de la littérature et de données produites sur différents terrains au Sahara et dans la péninsule Arabique (dépression de Kharga en Égypte, Nefzaoua en Tunisie et monts Hajar aux Émirats arabes unis), elle repose sursixcatégories de formes (ou de vestiges de ces formes) classées selon des critères génétiques (accumulation/ablation, éolienne/hydrique/anthropique/mixte). Certaines d'entre elles s'observent dans presque toutes les oasis et dans de nombreux sites de refuges préhistoriques, d'autres ont au contraire une distribution spatiale et temporelle beaucoup plus réduite car ils sont hérités de contextes ou à de périodes de transition plus ponctuels. La typologie proposée est nécessairement provisoire et gagnera à être enrichie par des éléments de comparaison en provenance d'autres sites et d'autres régions
Succès de la reproduction de prédateurs en contexte de changements climatiques et de la dynamique océanique – Application aux « central place foragers » des zones australes, approche par la modélisation individu centrée
No full textClimate change has certain impact on the marine ecosystems. A southward shift in productive frontal systems serving as the main foraging sites for many top predator species is likely to occur in the Subantarctic areas. Central place foragers, as seabirds and pinnipeds, are thus likely to cope with an increase in the distance between foraging locations and their land-based breeding colonies. We studied the impact of climate change on the breeding success and population dynamics of Antarctic fur seals (Arctocephalus gazella) at Kerguelen Islands by means of an individual based model we developped, MarCPFS (Marine Central Place Foragers Simulator) which showed that the survival of the female-pup pair is particularly sensitive to the distribution of preys (abundance and structure), to the memorization abilities of the best resource sites found by the female during the rearing period, to the female size and to the foraging distance which it is necessary to cover at each trip. The results suggest that during the next three decades a southward shift greater than 2 km year-1 could compromise the survival and the sustainability of the populations. A coupling with a model of simulation of the oceanic dynamics and the resource (SEAPODYM) allowed projections till the end of this century based on scenarios RCP8.5 of the IPCC (2014), confirming the trends previously obtained. Globally, these works lead us to conclude with pessimistic perspectives about the sustainability of populations even when considering an evolution through time towards individuals of greater sizes.Les changements climatiques ont un impact certain sur les écosystèmes marins. Un déplacement vers le sud des principaux systèmes de front servant de sites de nourrissage pour de nombreuses espèces de prédateurs supérieurs est susceptible de se produire dans les zones subantarctiques. Les « central place foragers », tels que les pinnipèdes, sont susceptibles de faire face à une augmentation de la distance entre leurs lieux d'alimentation et leurs colonies d'élevage. Nous avons étudié l’impact des changements climatiques sur le succès d’élevage et la dynamique de population des otaries à fourrure (Arctocephalus gazella) des Îles Kerguelen par le biais du développement du modèle individu centré, MarCPFS (Marine Central Place Foragers Simulator) qui montre que la survie du couple femelle-jeune est particulièrement sensible à la répartition des proies (abondance et structure), à la capacité de mémorisation des meilleurs sites de nourrissages trouvés par la femelle pendant la période d'élevage, à la taille des femelles et à la distance qu'il faut parcourir pour trouver la ressource. Les résultats suggèrent qu’au cours des trois prochaines décennies un déplacement vers le sud supérieur à 2km an 1 pourrait compromettre la survie et la durabilité des populations. Un couplage avec un modèle de simulation de la dynamique océanique et de la ressource (SEAPODYM) a permis des projections jusqu’à la fin de ce siècle basées sur le scénarios RCP8.5 du GIEC (2014), confirmant les tendances mises à jour précédemment. Ces travaux montrent que les perspectives de maintien des populations sont pessimistes y compris en envisageant une adaptation de la taille des individus
A bipolar role of the transcription factor ERG for cnidarian germ layer formation and apical domain patterning
No full textInternational audienceGerm layer formation and axial patterning are biological processes that are tightly linked during embryonic development of most metazoans. In addition to canonical WNT, it has been proposed that ERK-MAPK signaling is involved in specifying oral as well as aboral territories in cnidarians. However, the effector and the molecular mechanism underlying latter phenomenon is unknown. By screening for potential effectors of ERK-MAPK signaling in both domains, we identified a member of the ETS family of transcription factors, Nverg that is bi-polarily expressed prior to gastrulation. We further describe the crucial role of NvERG for gastrulation, endomesoderm as well as apical domain formation. The molecular characterization of the obtained NvERG knock-down phenotype using previously described as well as novel potential downstream targets, provides evidence that a single transcription factor, NvERG, simultaneously controls expression of two different sets of downstream targets, leading to two different embryonic gene regulatory networks (GRNs) in opposite poles of the developing embryo. We also highlight the molecular interaction of cWNT and MEK/ERK/ERG signaling that provides novel insight into the embryonic axial organization of Nematostella, and show a cWNT repressive role of MEK/ERK/ERG signaling in segregating the endomesoderm in two sub-domains, while a common input of both pathways is required for proper apical domain formation. Taking together, we build the first blueprint for a global cnidarian embryonic GRN that is the foundation for additional gene specific studies addressing the evolution of embryonic and larval development
The ERN1 transcription factor gene is a target of the CCaMK/CYCLOPS complex and controls rhizobial infection in Lotus japonicus
No full textBacterial accommodation inside living plant cells is restricted to the nitrogen-fixing root nodule symbiosis. In many legumes, bacterial uptake is mediated via tubular structures called infection threads (ITs). To identify plant genes required for successful symbiotic infection, we screened an ethyl methanesulfonate mutagenized population of Lotus japonicus for mutants defective in IT formation and cloned the responsible gene, ERN1, encoding an AP2/ERF transcription factor. We performed phenotypic analysis of two independent L. japonicus mutant alleles and investigated the regulation of ERN1 via transactivation and DNA-protein interaction assays. In ern1 mutant roots, nodule primordia formed, but most remained uninfected and bacterial entry via ITs into the root epidermis was abolished. Infected cortical nodule cells contained bacteroids, but transcellular ITs were rarely observed. A subset exhibited localized cell wall degradation and loss of cell integrity associated with bacteroid spread into neighbouring cells and the apoplast. Functional promoter studies revealed that CYCLOPS binds in a sequence-specific manner to a motif within the ERN1 promoter and in combination with CCaMK positively regulates ERN1 transcription. We conclude that the activation of ERN1 by CCaMK/CYCLOPS complex is an important step controlling IT-mediated bacterial progression into plant cells
Plant NF-Y transcription factors: Key players in plant-microbe interactions, root development and adaptation to stress.
No full textNF-Ys are heterotrimeric transcription factors composed by the NF-YA, NF-YB and NF-YC subunits. In plants, NF-Y subunits are encoded by multigene families whose members show structural and functional diversifications. An increasing number of NF-Y genes has been shown to play key roles during different stages of root nodule and arbuscular mycorrhizal symbiosis, as well as during the interaction of plants with pathogenic microorganisms. Individual members of the NF-YA and NF-YB families have also been implicated in the development of primary and lateral roots. In addition, different members of the NF-YA and NF-YB gene families from mono- and di-cotyledonous plants have been involved in plant responses to water and nutrient scarcity. This review presents the most relevant and striking results concerning these NF-Y subunits. A phylogenetic analysis of the functionally characterized NF-Y genes revealed that, across plant species, NF-Y proteins functioning in the same biological process tend to belong to common phylogenetic groups. Finally, we discuss the forthcoming challenges of plant NF-Y research, including the detailed dissection of expression patterns, the elucidation of functional specificities as well as the characterization of the potential NF-Y-mediated epigenetic mechanisms by which they control the expression of their target genes. This article is part of a Special Issue entitled: Nuclear Factor Y in Development and Disease, edited by Prof. Roberto Mantovani
Life and death of proteins after protease cleavage: protein degradation by the N-end rule pathway
No full textThe N-end rule relates the stability of a protein to the identity of its N-terminal residue and some of its modifications. Since its discovery in the 1980s, the repertoire of N-terminal degradation signals has expanded, leading to a diversity of N-end rule pathways. Although some of these newly discovered N-end rule pathways remain largely unexplored in plants, recent discoveries have highlighted roles of N-end rule-mediated protein degradation in plant defense against pathogens and in cell proliferation during organ growth. Despite this progress, a bottleneck remains the proteome-wide identification of N-end rule substrates due to the prerequisite for endoproteolytic cleavage and technical limitations. Here, we discuss the recent diversification of N-end rule pathways and their newly discovered functions in plant defenses, stressing the role of proteases. We expect that novel proteomics techniques (N-terminomics) will be essential for substrate identification. We review these methods, their limitations and future developments