Comment mesurer l'impact érosif des dynamiques de l'occupation du sol ? Approche pluridisciplinaire dans la vallée de la Choisille (Indre-et-Loire, France)

International audienceThe Choisille valley, in the north of Tours (37), has been a laboratory for a multidisciplinary experiment which was aimed at measuring the impact of human activities on soil erosion, conducted within the ECLIPSE II program. We propose a synthesis of the acquired knowledge about land use evolution based on archaeological, written and environmental data analyzed within a GIS. This information documents the settlement and landscape dynamics at different time and space scales, and provides a partial explanation to the variation of sediments recording within the Choisille valley.La vallée de la Choisille au nord de Tours (37) a été un laboratoire pour une expérience multidisciplinaire visant à mesurer l'impact des activités anthropiques sur l'érosion des sols, expérience réalisée dans le cadre du programme ECLIPSE II. Nous proposons la synthèse des connaissances acquises sur l'évolution de l'occupation du sol à partir des données archéologiques, écrites, planimétriques et environnementales analysées au sein d'un SIG. Ces informations documentent les dynamiques de l'habitat et du paysage à différentes échelles de temps et d'espace, et permettent en partie d'expliquer les variations de l'enregistrement sédimentaire au sein de la vallée de la Choisille

Occupation du sol et impact érosif dans la vallée de la Choisille (France, Indre-et-Loire). Approches croisées pour la restitution des paysages anciens.

International audienceThe Choisille catchment, a tributary of the Loire in the north of Tours, is used since 2003 as a common geographical framework for investigation of geologists and archaeologists teams with the aim of studying the main steps of land use of this space in the long term and the impact of human activities on soil erosion and sedimentation in wetlands during the Holocene. Archaeological fieldwalking surveys, analysis of medieval and modern written sources and sedimentological and palynological cores-drillings have been made. The comparison of these works highlights an anthropogenic forcing on sediment fluxes since the Bronze Age, with an increasing intensity since the Middle Ages, but also raises questions about discrepancies between the different types of sources. The limits of each discipline and the "blind spots" between them stress their complementarities and the necessity to cross them to approach the ancient realities.Le bassin-versant de la Choisille, affluent de la Loire au nord de Tours, sert depuis 2003 de cadre géographique commun d'investigation pour les équipes de géologues et d'archéologues dont le but est de mesurer, dans la longue durée, les principales phases d'occupation humaine de l'espace et l'impact des activités anthropiques sur l'érosion des sols et la sédimentation dans les zones humides durant l'Holocène. Des prospections archéologiques de surface, le dépouillement des sources écrites médiévales et modernes et des carottages sédimentologiques et palynologiques ont été réalisés. Le croisement de ces travaux met en lumière un forçage anthropique sur les flux sédimentaires dès l'Âge du Bronze, avec une intensité plus forte depuis le Moyen Âge, mais amène également à s'interroger sur les discordances observées entre les différents types de sources. Les limites propres à chaque discipline et les " angles morts " entre elles soulignent leur complémentarité et la nécessité de les multiplier pour approcher les réalités anciennes

Mib1 prevents Notch Cis-inhibition to defer differentiation and preserve neuroepithelial integrity during neural delamination

<div><p>The vertebrate neuroepithelium is composed of elongated progenitors whose reciprocal attachments ensure the continuity of the ventricular wall. As progenitors commit to differentiation, they translocate their nucleus basally and eventually withdraw their apical endfoot from the ventricular surface. However, the mechanisms allowing this delamination process to take place while preserving the integrity of the neuroepithelial tissue are still unclear. Here, we show that Notch signaling, which is classically associated with an undifferentiated state, remains active in prospective neurons until they delaminate. During this transition period, prospective neurons rapidly reduce their apical surface and only later down-regulate N-Cadherin levels. Upon Notch blockade, nascent neurons disassemble their junctions but fail to reduce their apical surface. This disrupted sequence weakens the junctional network and eventually leads to breaches in the ventricular wall. We also provide evidence that the Notch ligand Delta-like 1 (Dll1) promotes differentiation by reducing Notch signaling through a <i>Cis</i>-inhibition mechanism. However, during the delamination process, the ubiquitin ligase Mindbomb1 (Mib1) transiently blocks this <i>Cis</i>-inhibition and sustains Notch activity to defer differentiation. We propose that the fine-tuned balance between Notch <i>Trans</i>-activation and <i>Cis</i>-inhibition allows neuroepithelial cells to seamlessly delaminate from the ventricular wall as they commit to differentiation.</p></div

Software Verification of Orion Cockpit Displays

NASA's latest spacecraft Orion is in the development process of taking humans deeper into space. Orion is equipped with three main displays to monitor and control the spacecraft. To ensure the software behind the glass displays operates without faults, rigorous testing is needed. To conduct such testing, the Rapid Prototyping Lab at NASA's Johnson Space Center along with the University of Texas at Tyler employed a software verification tool, EggPlant Functional by TestPlant. It is an image based test automation tool that allows users to create scripts to verify the functionality within a program. A set of edge key framework and Common EggPlant Functions were developed to enable creation of scripts in an efficient fashion. This framework standardized the way to code and to simulate user inputs in the verification process. Moreover, the Common EggPlant Functions can be used repeatedly in verification of different displays

On the assimilation of optical reflectances and snow depth observations into a detailed snowpack model

International audienceThis paper examines the ability of optical re-flectance data assimilation to improve snow depth and snow water equivalent simulations from a chain of models with the SAFRAN meteorological model driving the detailed multi-layer snowpack model Crocus now including a two-stream radiative transfer model for snow, TARTES. The direct use of reflectance data, allowed by TARTES, instead of higher level snow products, mitigates uncertainties due to commonly used retrieval algorithms. Data assimilation is performed with an ensemble-based method, the Sequential Importance Resampling Particle filter , to represent simulation uncertainties. In snowpack mod-eling, uncertainties of simulations are primarily assigned to meteorological forcings. Here, a method of stochastic perturbation based on an autoregressive model is implemented to explicitly simulate the consequences of these uncertainties on the snowpack estimates. Through twin experiments, the assimilation of synthetic spectral reflectances matching the MODerate resolution Imaging Spectroradiometer (MODIS) spectral bands is examined over five seasons at the Col du Lautaret, located in the French Alps. Overall, the assimilation of MODIS-like data reduces by 45 % the root mean square errors (RMSE) on snow depth and snow water equivalent. At this study site, the lack of MODIS data on cloudy days does not affect the assimilation performance significantly. The combined assimilation of MODIS-like reflectances and a few snow depth measurements throughout the 2010/2011 season further reduces RMSEs by roughly 70 %. This work suggests that the assimilation of optical reflectances has the potential to become an essential component of spatialized snowpack simulation and forecast systems. The assimilation of real MODIS data will be investigated in future works

Loss of CIC promotes mitotic dysregulation and chromosome segregation defects

Background: CIC is a transcriptional repressor inactivated by loss-of-function mutations in several cancer types, including gliomas, lung cancers, and gastric adenocarcinomas. CIC alterations and/or loss of CIC activity have been associated with poorer outcomes and more aggressive phenotypes across cancer types, which is consistent with the notion that CIC functions as a tumour suppressor across a wide range of contexts. Results: Using mammalian cells lacking functional CIC, we found that CIC deficiency was associated with chromosome segregation (CS) defects, resulting in chromosomal instability and aneuploidy. These CS defects were associated with transcriptional dysregulation of spindle assembly checkpoint and cell cycle regulators. We also identified novel CIC interacting proteins, including core members of the SWI/SNF complex, and showed that they cooperatively regulated the expression of genes involved in cell cycle regulation. Finally, we showed that loss of CIC and ARID1A cooperatively increased CS defects and reduced cell viability. Conclusions: Our study ascribes a novel role to CIC as an important regulator of the cell cycle and demonstrates that loss of CIC can lead to chromosomal instability and aneuploidy in human and murine cells through defects in CS, providing insight into the underlying mechanisms of CIC's increasingly apparent role as a "pan-cancer" tumour suppressor

Distributed Semantic Web Data Management in HBase and MySQL Cluster

Various computing and data resources on the Web are being enhanced with machine-interpretable semantic descriptions to facilitate better search, discovery and integration. This interconnected metadata constitutes the Semantic Web, whose volume can potentially grow the scale of the Web. Efficient management of Semantic Web data, expressed using the W3C's Resource Description Framework (RDF), is crucial for supporting new data-intensive, semantics-enabled applications. In this work, we study and compare two approaches to distributed RDF data management based on emerging cloud computing technologies and traditional relational database clustering technologies. In particular, we design distributed RDF data storage and querying schemes for HBase and MySQL Cluster and conduct an empirical comparison of these approaches on a cluster of commodity machines using datasets and queries from the Third Provenance Challenge and Lehigh University Benchmark. Our study reveals interesting patterns in query evaluation, shows that our algorithms are promising, and suggests that cloud computing has a great potential for scalable Semantic Web data management.Comment: In Proc. of the 4th IEEE International Conference on Cloud Computing (CLOUD'11