36 research outputs found

    SMOS based high resolution soil moisture estimates for Desert locust preventive management

    Full text link
    This paper presents the first attempt to include soil moisture information from remote sensing in the tools available to desert locust managers. The soil moisture requirements were first assessed with the users. The main objectives of this paper are: i) to describe and validate the algorithms used to produce a soil moisture dataset at 1 km resolution relevant to desert locust management based on DisPATCh methodology applied to SMOS and ii) the development of an innovative approach to derive high-resolution (100 m) soil moisture products from Sentinel-1 in synergy with SMOS data. For the purpose of soil moisture validation, 4 soil moisture stations where installed in desert areas (one in each user country). The soil moisture 1 km product was thoroughly validated and its accuracy is amongst the best available soil moisture products. Current comparison with in-situ soil moisture stations shows good values of correlation (R>0.7R>0.7) and low RMSE (below 0.04 m3 m−3). The low number of acquisitions on wet dates has limited the development of the soil moisture 100 m product over the Users Areas. The Soil Moisture product at 1 km will be integrated into the national and global Desert Locust early warning systems in national locust centres and at DLIS-FAO, respectively

    The N-Terminal Domain of the Arenavirus L Protein Is an RNA Endonuclease Essential in mRNA Transcription

    Get PDF
    Arenaviridae synthesize viral mRNAs using short capped primers presumably acquired from cellular transcripts by a ‘cap-snatching’ mechanism. Here, we report the crystal structure and functional characterization of the N-terminal 196 residues (NL1) of the L protein from the prototypic arenavirus: lymphocytic choriomeningitis virus. The NL1 domain is able to bind and cleave RNA. The 2.13 Å resolution crystal structure of NL1 reveals a type II endonuclease α/β architecture similar to the N-terminal end of the influenza virus PA protein. Superimposition of both structures, mutagenesis and reverse genetics studies reveal a unique spatial arrangement of key active site residues related to the PD…(D/E)XK type II endonuclease signature sequence. We show that this endonuclease domain is conserved and active across the virus families Arenaviridae, Bunyaviridae and Orthomyxoviridae and propose that the arenavirus NL1 domain is the Arenaviridae cap-snatching endonuclease

    Qualité de la formation professionnelle initiale au Maroc et impact des actions de formation continue sur les performances des entreprises marocaines

    Get PDF
    Chapitre 5 du rapport n° FEM 31-23 Evaluation de la qualité du système de la formation professionnelle et son impact sur le développement : Comparaison Maroc –Tunisie dans le cadre du programme de recherche FEMISE 2006-200

    Weak Solutions for a Coupled System of Partial Pettis Hadamard Fractional Integral Equations

    No full text
    In this paper we investigate the existence of weak solutions under the Pettis integrability assumption for a coupled system of partial integral equations via Hadamard’s fractional integral, by applying the technique of measure of weak noncompactness and Mönch’s fixed point theorem

    Irrigation Amounts and Timing Retrieval through Data Assimilation of Surface Soil Moisture into the FAO-56 Approach in the South Mediterranean Region

    No full text
    International audienceAgricultural water use represents more than 70% of the world’s freshwater through irrigation water inputs that are poorly known at the field scale. Irrigation monitoring is thus an important issue for optimizing water use in particular with regards to the water scarcity that the semi-arid regions are already facing. In this context, the aim of this study is to develop and evaluate a new approach to predict seasonal to daily irrigation timing and amounts at the field scale. The method is based on surface soil moisture (SSM) data assimilated into a simple land surface (FAO-56) model through a particle filter technique based on an ensemble of irrigation scenarios. The approach is implemented in three steps. First, synthetic experiments are designed to assess the impact of the frequency of observation, the errors on SSM and the a priori constraints on the irrigation scenarios for different irrigation techniques (flooding and drip). In a second step, the method is evaluated using in situ SSM measurements with different revisit times (3, 6 and 12 days) to mimic the available SSM product derived from remote sensing observation. Finally, SSM estimates from Sentinel-1 are used. Data are collected on different wheat fields grown in Morocco, for both flood and drip irrigation techniques in addition to rainfed fields used for an indirect evaluation of the method performance. Using in situ data, accurate results are obtained. With an observation every 6 days to mimic the Sentinel-1 revisit time, the seasonal amounts are retrieved with R > 0.98, RMSE < 32 mm and bias < 2.5 mm. Likewise, a good agreement is observed at the daily scale for flood irrigation as more than 70% of the detected irrigation events have a time difference from actual irrigation events shorter than 4 days. Over the drip irrigated fields, the statistical metrics are R = 0.74, RMSE = 24.8 mm and bias = 2.3 mm for irrigation amounts cumulated over 15 days. When using SSM products derived from Sentinel-1 data, the statistical metrics on 15-day cumulated amounts slightly dropped to R = 0.64, RMSE = 28.7 mm and bias = 1.9 mm. The metrics on the seasonal amount retrievals are close to assimilating in situ observations with R = 0.99, RMSE = 33.5 mm and bias = −18.8 mm. Finally, among four rainfed seasons, only one false event was detected. This study opens perspectives for the regional retrieval of irrigation amounts and timing at the field scale and for mapping irrigated/non irrigated area

    Antagonists of the adenosine A 2A receptor based on a 2-arylbenzoxazole scaffold: Investigation of the C5- and C7-positions to enhance affinity

    No full text
    International audienceWe have recently reported a series of 2-furoyl-benzoxazoles as potential A2A adenosine receptor (A2AR) antagonists. Two hits were identified with interesting pharmacokinetic properties but were find to bind the hA2AR receptor in the micromolar-range. Herein, in order to enhance affinity toward the hA2AR, we explored the C5- and C7-position of hits 1 and 2 based on docking studies. These modifications led to compounds with nanomolar-range affinity (e.g. 6a, Ki = 40 nM) and high antagonist activity (e.g. 6a, IC50 = 70.6 nM). Selected compounds also exhibited interesting in vitro DMPK (Drug Metabolism and Pharmacokinetics) properties including high solubility and low cytotoxicity. Therefore, the benzoxazole ring appears as a highly effective scaffold for the design of new A2A antagonists

    Calibrating an evapotranspiration model using radiometric surface temperature, vegetation cover fraction and near-surface soil moisture data

    No full text
    International audienceAn accurate representation of the partitioning between soil evaporation and plant transpiration is an asset for modeling crop evapotranspiration (ET) along the agricultural season. The Two-Surface energy Balance (TSEB) model operates the ET partitioning by using the land surface temperature (LST), vegetation cover fraction (fc), and the Priestley Taylor (PT) assumption that relates transpiration to net radiation via a fixed PT coefficient (αPT). To help constrain the evaporation/transpiration partition of TSEB, a new model (named TSEB-SM) is developed by using, in addition to LST and fc data, the near-surface soil moisture (SM) as an extra constraint on soil evaporation. An innovative calibration procedure is proposed to retrieve three key parameters: αPT and the parameters (arss and brss) of a soil resistance formulation. Specifically, arss and brss are retrieved at the seasonal time scale from SM and LST data with fc  0.5. The new ET model named TSEB-SM is tested over 1 flood- and 2 drip-irrigated wheat fields using in situ data collected during two field experiments in 2002–2003 and 2016–2017. The calibration algorithm is found to be remarkably stable as αPT, arss and brss parameters converge rapidly in few (2–3) iterations. Retrieved values of αPT, arss and brss are in the range 0.0–1.4, 5.7–9.5, and 1.4–6.9, respectively. Calibrated daily αPT mainly follows the phenology of winter wheat crop with a maximum value coincident with the full development of green biomass and a minimum value reached at harvest. The temporal variations of αPT before senescence are attributed to the dynamics of both root-zone soil moisture. Moreover, the overall (for the three sites) root mean square difference between the ET simulated by TSEB-SM and eddy-covariance measurements is 67 W m−2 (24% relative error), compared to 108 W m−2 (38% relative error) for the original version of TSEB using default parameterization (αPT = 1.26). Such a calibration strategy has great potential for applications at multiple scales using remote sensing data including thermal-derived LST, solar reflectance-derived fc and microwave-derived SM
    corecore