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International audience; Study region : Atlas Mountains located in Morocco. Study focus : Mountainous regions constitute an area of water production, while water is used in downstream plains. In Central Morocco, the Atlas Mountains represent the most important water supply in the country. The solid part of precipitation forms seasonal snowpack. Snowmelt is important for the water supply for different uses in neighbouring plains. Accurate knowledge of snow water equivalent is key information needed by policy-makers to help design and implement appropriate allocation strategies for water resource management. The objective of this paper is to provide a summary of our research activities on snow hydrology in the Atlas Mountains during the past twenty years. The approach combines in situ measurements, remote sensing, and modeling.New hydrological insights for the region : Following a description of the context of the Moroccan Atlas Mountains and the experimental network, an overview of the main results obtained is presented: the characterization of the spatiotemporal dynamics of snow cover; the impact of the North Atlantic Oscillation on the snow-covered area; the snowmelt contribution to the flows of the Atlas rivers; the contribution of snowmelt to surface and groundwater recharge and the quantification of climate change impacts on snow and associated runoff from the Atlas Mountains. We also present challenges and future research perspectives within this topic.

Estimating snowmelt in semi-arid mountain ranges is an important but challenging task, due to the large spatial variability of the snow cover and scarcity of field observations. Adding solar radiation as snowmelt predictor within empirical snow models is often done to account for topographically induced variations in melt rates. This study examines the added value of including different treatments of solar radiation within empirical snowmelt models and benchmarks their performance against MODIS snow cover area (SCA) maps over the 2003-2016 period. Three spatially distributed, enhanced temperature index models that, respectively, include the potential clear-sky direct radiation, the incoming solar radiation and net solar radiation were compared with a classical temperature-index (TI) model to simulate snowmelt, SWE and SCA within the Rheraya basin in the Moroccan High Atlas Range. Enhanced models, particularly that which includes net solar radiation, were found to better explain the observed SCA variability compared to the TI model. However, differences in model performance in simulating basin wide SWE and SCA were small. This occurs because topographically induced variations in melt rates simulated by the enhanced models tend to average out, a situation favored by the rather uniform distribution of slope aspects in the basin. While the enhanced models simulated more heterogeneous snow cover conditions, aggregating the simulated SCA from the 100 m model resolution towards the MODIS resolution (500 m) suppresses key spatial variability related to solar radiation, which attenuates the differences between the TI and the radiative models. Our findings call for caution when using MODIS for calibration and validation of spatially distributed snow models.

International audience; Melt water runoff from seasonal snow in the High Atlas range is an essential water resource in Morocco. However, there are only few meteorological stations in the high elevation areas and therefore it is challenging to estimate the distribution of snow water equivalent (SWE) based only on in situ measurements. In this work we assessed the performance of ERA5 and MERRA-2 climate reanalysis to compute the spatial distribution of SWE in the High Atlas. We forced a distributed snowpack evolution model (SnowModel) with downscaled ERA5 and MERRA-2 data at 200 m spatial resolution. The model was run over the period 1981 to 2019 (37 water years). Model outputs were assessed using observations of river discharge, snow height and MODIS snow-covered area. The results show a good performance for both MERRA-2 and ERA5 in terms of reproducing the snowpack state for the majority of water years, with a lower bias using ERA5 forcing.

PurposeThis paper studies the preemptive scheduling problem of independent jobs on identical machines. The purpose of this paper is to minimize the makespan under the imposed constraints, namely, the ones that relate the transportation delays which are required to transport a preempted job from one machine to another. This study considers the case when the transportation delays are variable.Design/methodology/approachThe contribution is twofold. First, this study proposes a new linear programming formulation in real and binary decision variables. Then, this study proposes and implements a solution strategy, which consists of two stages. The goal of the first stage is to obtain the best machines order using a local search strategy. For the second stage, the objective is to determine the best possible sequence of jobs. To solve the preemptive scheduling problem with transportation delays, this study proposes a heuristic and two metaheuristics (simulated annealing and variable neighborhood search), each with two modes of evaluation.FindingsComputational experiments are presented and discussed on randomly generated instances.Practical implicationsThe study has implications in various industrial environments when the preemption of jobs is allowed.Originality/valueThis study proposes a new linear programming formulation for the problem with variable transportation delays as well as a corresponding heuristic and metaheuristics.

International audience; This paper addresses the problem of scheduling jobs on a two-machine open shop subject to constraints given by an agreement graph G, such that jobs can be processed simultaneously on different machines if and only if they are represented by adjacent vertices in G. The problem of minimizing the maximum completion time (makespan) is strongly NP-hard for three distinct values of processing times and for G being a bipartite graph. We extend the study presented in [3] and [4] to the proportionate open shop system. We first prove the NP-hardness of the case of two values of processing times and more general agreement graphs which closes definitely the complexity status of the problem. Then, we present some restricted cases that can be solved in polynomial time. We also derive new complexity results of the open shop under resource constraints and of the partition into triangles problem.

International audience; This paper addresses a generalization of the coupled-operations scheduling problem in the context of a flow shop environment. We consider the two-machine scheduling problem with the objective of minimizing the makespan. Each job consists of a coupled-operation to be processed first on the first machine and a single operation to be then processed on the second machine. A coupled-operation contains two operations separated by an exact time delay. The single operation can start on the second machine only when the coupled-operation on the first machine is completed. We prove the NP-completeness of two restricted versions of the general problem, whereas we also exhibit several other well solvable cases.

In arid and semi-arid areas, rainfall is often characterized by a strong spatial and temporal variability. These environmental factors, combined with the sparsity of the measurement networks in developing countries, constitute real constraints for water resources management. In recent years, several spatial rainfall measurement sources have become available, such as TRMM data (Tropical Rainfall Measurement Mission). In this study, the TRMM 3B42 Version 7 product was evaluated using rain gauges measurements from 19 stations in the Oum-Er-Bia (OER) basin located in the center of Morocco. The relevance of the TRMM product was tested by direct comparison with observations at different time scales (daily, monthly, and annual) between 1998 and 2010. Results show that the satellite product provides poor estimations of rainfall at the daily time scale giving an average Pearson correlation coefficient (r) of 0.2 and average Root Mean Square Error (RMSE) of 10 mm. However, the accuracy of TRMM rainfall is improved when temporally averaged to monthly time scale (r of 0.8 and RMSE of 28 mm) or annual time scale (r of 0.71 and RMSE of 157 mm). Moreover, improved correlation with observed data was obtained for data spatially averaged at the watershed scale. Therefore, at the monthly and annual time scales, TRMM data can be a useful source of rainfall data for water resources monitoring and management in ungauged basins in semi-arid regions.

International audience

This research investigates the case of a machine subject to a stochastic degradation. A condition-based replacement policy is adopted to keep the system running. The replacements are carried out with spare parts of a given quality determined by their degradation level. The replacement spare parts are either new or used: the used ones are the parts recovered from the machine at the time of previous replacements. Before the replacement, a remanufacturing process can be applied on the recovered part to improve its quality, by reducing its degradation level. The purpose of this paper is to propose an optimal maintenance policy, by determining dynamically (i.e. at each moment of decision making): the decision thresholds, inspection dates and spare parts qualities to be installed in the machine. Two components approach is proposed to achieve these objectives, the first component is executed offline and the second component is run online. Numerical examples are presented to illustrate the efficiency of the proposed approach.

López-Moreno, Juan I. et. al.- 10 páginas.- Ilustraciones.- This article is an open access article distributed under the terms of the Creative Commons Attribution 3.0 licence (https://creativecommons.org/licenses/by/3.0/), In this study we quantified the sensitivity of the snow to climate warming in selected mountain sites having a Mediterranean climate, including the Pyrenees in Spain and Andorra, the Sierra Nevada in Spain and California (USA), the Atlas in Morocco, and the Andes in Chile. Meteorological observations from high elevations were used to simulate the snow energy and mass balance (SEMB) and calculate its sensitivity to climate. Very different climate sensitivities were evident amongst the various sites. For example, reductions of 9–19% and 6–28 days in the mean snow water equivalent (SWE) and snow duration, respectively, were found per C increase. Simulated changes in precipitation (± 20%) did not affect the sensitivities. The Andes and Atlas Mountains have a shallow and cold snowpack, and net radiation dominates the SEMB; and explains their relatively low sensitivity to climate warming. The Pyrenees and USA Sierra Nevada have a deeper and warmer snowpack, and sensible heat flux is more important in the SEMB; this explains the much greater sensitivities of these regions. Differences in sensitivity help explain why in regions where climate models project relatively greater temperature increases and drier conditions by 2050 (such as the Spanish Sierra Nevada and the Moroccan Atlas Mountains), the decline in snow accumulation and duration is similar to other sites (such as the Pyrenees and the USA Sierra Nevada), where models project stable precipitation and more attenuated warming. The snowpack in the Andes (Chile) exhibited the lowest sensitivity to warming, and is expected to undergo only moderate change (a decrease of, This study was funded by the research projects CGL2014-52599-P‘ Estudio del manto de nieve en la montaña española y su respuesta a la variabilidad y cambio climatico’ (Ministry of Economy and Development, MINECO), I-link+ project (Spanish Research Council, CSIC) Development of methods for monitoring and simulating snow cover and water resources and their response to climate change in semiarid Northern Chile’, and CLIMPY:‘Characterization of the evolution of climate and provision of information for adaptation in the Pyrenees’(FEDER-POCTEFA). It is a contribution to the International Network for Alpine Research Catchment Hydrology (INARCH) under the Global Energy and Water Exchanges (GEWEX) Project, which aims to compare snow regimes in mountains around the world.

Snowpack significantly contributes to water resources in North Africa. The objective of this work was to analyze the impact of the North Atlantic Oscillation (NAO) on rainfall and temperature in Morocco at a sub-seasonal scale and to evaluate, for the first time, linkages between the NAO and snow cover area (SCA) derived from remote sensing observations. For this purpose, we analyzed daily SCA products (2000-2013) from the MODIS sensor, meteorological data from 37 stations (1993-2011), NCEP re-analysis of surface air temperature and rainfall rate, and a monthly NAO index. The linear linkages sought using simple correlation analysis demonstrated that negative (positive) NAO (1) is associated with enhanced (reduced) rainfall in December and February for the northern part of the country; (2) occurs with above-normal (below-normal) temperature and, in contrast with rainfall, the correlation persists far inland and late in the season. These results highlight a possible competing influence of NAO on the snowpack dynamic through rainfall and temperature. Indeed, negative (positive) NAO tends to favor earlier (later) melting and lesser (greater) SCA in spring (April-May) through milder temperatures. Results have direct implications for seasonal forecast of SCA in Morocco.

We consider a chain reentrant shop problem with m machines, in which a no-wait constraint is imposed. Each job goes through m machines in a fixed order and return back to the first machine for its last operation. We seek to minimize the overall finish time (makespan). We first proof some new NP-hard problems in the case of two machines. For the resolution of the general problem we propose a genetic algorithm with numerical experiments.

International audience; The two-machine chain-reentrant shop scheduling with the objective of minimizing the makespan, assumes that the taskspass from the first machine to the second and return back to the first machine. In this paper, we consider the same problem inwhich an exact time lag between the two operations on the first machine is imposed. In Amrouche and Boudhar (2016) theauthors proved that this problem is NP-hard in the strong sense in the case of identical time lags l j = L. We propose heuristicalgorithms with empirical results for the latter. In addition, we establish a new NP-hardness result and some polynomialcases.

INTRODUCTION : Le médecin généraliste (MG) occupe une place centrale dans l’organisation de la rééducation de la sclérose en plaques (SEP), qui reste prépondérante dans sa prise en charge symptomatique. Cette étude vise à rechercher les facteurs favorisants et les obstacles à cette prise en charge par le MG, ainsi qu’à recueillir leurs suggestions pour son optimisation. MÉTHODES : Il s’agissait d’une étude qualitative, par la méthode des entretiens individuels semi-dirigés, auprès de 15 MG exerçant dans le département de l’Oise, afin d’obtenir la saturation des données. Chaque enregistrement d’entretien a été retranscrit intégralement. Ces données ont été analysées par deux investigateurs indépendants, dont l’un était l’auteur de la thèse. RÉSULTATS : Les facteurs favorisants étaient liés à la relation MG/malade, au patient, à certains aspects de la prise en charge en cabinet de MG ou en institution. Les obstacles étaient liés à la place du MG, à son savoir en matière de rééducation, notamment sur la question de l’activité physique dans le cadre de la SEP, à ses prescriptions de rééducation, aux limites du patient, aux difficultés de communication entre les différents acteurs de cette prise en charge, et aux difficultés d’ordre technique. Leurs suggestions concernaient le renforcement de la formation et de la communication pour permettre une prise en charge plus globale. Des actions politiques permettant d’allouer plus de moyens à cette prise en charge étaient également préconisées. DISCUSSION : Malgré leur relation privilégiée avec le patient atteint de SEP, les MG considéraient leur place non privilégiée dans l’organisation de cette prise en charge. Des moyens supplémentaires seraient nécessaires pour leur permettre de mener celle-ci à bien. Le nombre restreint de patient atteint de SEP par MG risque cependant de limiter les actions sur le plan politique. CONCLUSION : Les facteurs influençant la prise en charge rééducative de la SEP par le MG sont multiples. Le complément de ce travail par une étude quantitative pourrait lui permettre une portée plus significative et la mise en place de moyens supplémentaires.

International audience; Dans ce travail, Nous considérons le problème du flowshop à deux machines avec des opérations couplées.Chaque tâche est composée de deux opérations couplées sur la première machine séparées par un délai exact et d'une seule opération sur la deuxième machine. L'objectif est de minimiser le makespan. Nous étudions la complexité d'un sous problème et nous montrons qu'il est NP-difficile. Pour la résolution du problème général, nous proposons des heuristiques avec des expérimentations numériques et nous présentons des sous problèmes polynomiaux.

International audience

International audience

Motivated by the change of regulations in the matter of sustainability, but also by pure economic constraints, several industries have found themselves obligated to develop new methods and models for the management of products that are at the end of their life cycle. In this context, the remanufacturing aims at managing the recovery of the product’s value before its end of life. This type of action will extend the product life cycle and save the use of the raw material. These remanufactured products will be re-injected in a market that serves another class of customers, different from the one using new products. In other cases, the remanufactured products are reused as spare parts for the maintenance, but this reuse may vary according to the maintenance strategy adopted. This thesis focuses on the integration of a hybrid flow supply of spare parts in a service model based on stochastic degradation of a production system. Two types of spare parts supply flows are studied: a direct flow and reverse flow. The direct flow is represented by the use of new spare parts and the reverse flow is represented by the reuse of the recovered parts during the replacements, with the ability to perform remanufacturing action to improve the degradation level of these spare parts. Several issues were treated to better understand the impact of remanufacturing policies over the performance of a production system. At the beginning we started our study with production systems composed of a single machine. In this context, we proposed sequential studies then integrated one to optimize the maintenance policy as well as the Hybrid provisioning in regard to spare parts destined to replacement actions. Similarly, we’ve studied the production management subjected to quality constraint based on the machine’s degradation process. Furthermore, we’ve presented generalizations of studied models within the context of a production system composed of several machines. Finally, we’ve developed an aid-to-decision-design tool for production systems within the remanufacturing process. This problematic aims at –from a strategic point- selecting the best group of machines to build a new system of production that is able to satisfy the constraints of a production defined by the decision maker, Motivés par l'évolution des réglementations en matière d'écologie mais aussi par des contraintes purement économiques, plusieurs secteurs industriels se sont retrouvés dans l'obligation de développer de nouvelles méthodes et modèles pour la gestion des produits en fin de vie. Dans ce contexte, la remanufacturation vise à gérer la récupération de la valeur d’un produit avant sa fin de vie. Elle permet de prolonger le cycle de vie du produit et d’économiser une partie des besoins industriels en matière première. Ces produits remanufacturés seront remis dans le marché et destinés à une autre catégorie de clients, différente de celle des produits neufs. Dans d'autres cas, les produits remanufacturés sont réutilisés sous la forme de pièces de rechange dans les actions de maintenance, mais cette réutilisation peut varier selon la stratégie de maintenance adoptée. Dans ce contexte, cette thèse s'intéresse à l’intégration d'un flux d’approvisionnement hybride en pièces de rechange dans un modèle de maintenance basé sur la dégradation stochastique d’un système de production. Deux types de flux d’approvisionnement en pièces de rechange sont étudiés : un flux direct et un flux inverse. Le flux direct est représenté par l'utilisation de pièces de rechange neuves et le flux inverse est représenté par la réutilisation des pièces récupérées lors des remplacements ultérieurs, avec la possibilité de réaliser une action de remanufacturation pour améliorer l'état de dégradation de ces pièces de rechange. Plusieurs problématiques ont été traitées pour permettre de comprendre l'impact et l'influence d'une politique de remanufacturation sur les performances d'un système de production. En effet, dans un premier temps, nous nous sommes intéressés à des systèmes de production composés d'une seule machine. Dans ce cadre, nous avons proposé des études séquentielles puis intégrées pour optimiser la politique de maintenance et celle de l'approvisionnement hybrides en pièces de rechange destinées aux actions de remplacements. Nous avons étudié également la gestion de production soumise à une contrainte de qualité basée sur l'évolution de la dégradation de la machine. Ensuite, et dans un second temps, nous avons présenté des généralisations des modèles étudiés dans le cadre de systèmes de production composés de plusieurs machines. Enfin, nous avons développé un outil d'aide à la décision pour conception de systèmes de production dans le cadre d'une politique de remanufacturation. Cette problématique - du niveau stratégique - vise à sélectionner le meilleur ensemble de machines pour construire un nouveau système de production capable de satisfaire les contraintes de production définies par décideur

Motivated by the change of regulations in the matter of sustainability, but also by pure economic constraints, several industries have found themselves obligated to develop new methods and models for the management of products that are at the end of their life cycle. In this context, the remanufacturing aims at managing the recovery of the product’s value before its end of life. This type of action will extend the product life cycle and save the use of the raw material. These remanufactured products will be re-injected in a market that serves another class of customers, different from the one using new products. In other cases, the remanufactured products are reused as spare parts for the maintenance, but this reuse may vary according to the maintenance strategy adopted. This thesis focuses on the integration of a hybrid flow supply of spare parts in a service model based on stochastic degradation of a production system. Two types of spare parts supply flows are studied: a direct flow and reverse flow. The direct flow is represented by the use of new spare parts and the reverse flow is represented by the reuse of the recovered parts during the replacements, with the ability to perform remanufacturing action to improve the degradation level of these spare parts. Several issues were treated to better understand the impact of remanufacturing policies over the performance of a production system. At the beginning we started our study with production systems composed of a single machine. In this context, we proposed sequential studies then integrated one to optimize the maintenance policy as well as the Hybrid provisioning in regard to spare parts destined to replacement actions. Similarly, we’ve studied the production management subjected to quality constraint based on the machine’s degradation process. Furthermore, we’ve presented generalizations of studied models within the context of a production system composed of several machines. Finally, we’ve developed an aid-to-decision-design tool for production systems within the remanufacturing process. This problematic aims at –from a strategic point- selecting the best group of machines to build a new system of production that is able to satisfy the constraints of a production defined by the decision maker, Motivés par l'évolution des réglementations en matière d'écologie mais aussi par des contraintes purement économiques, plusieurs secteurs industriels se sont retrouvés dans l'obligation de développer de nouvelles méthodes et modèles pour la gestion des produits en fin de vie. Dans ce contexte, la remanufacturation vise à gérer la récupération de la valeur d’un produit avant sa fin de vie. Elle permet de prolonger le cycle de vie du produit et d’économiser une partie des besoins industriels en matière première. Ces produits remanufacturés seront remis dans le marché et destinés à une autre catégorie de clients, différente de celle des produits neufs. Dans d'autres cas, les produits remanufacturés sont réutilisés sous la forme de pièces de rechange dans les actions de maintenance, mais cette réutilisation peut varier selon la stratégie de maintenance adoptée. Dans ce contexte, cette thèse s'intéresse à l’intégration d'un flux d’approvisionnement hybride en pièces de rechange dans un modèle de maintenance basé sur la dégradation stochastique d’un système de production. Deux types de flux d’approvisionnement en pièces de rechange sont étudiés : un flux direct et un flux inverse. Le flux direct est représenté par l'utilisation de pièces de rechange neuves et le flux inverse est représenté par la réutilisation des pièces récupérées lors des remplacements ultérieurs, avec la possibilité de réaliser une action de remanufacturation pour améliorer l'état de dégradation de ces pièces de rechange. Plusieurs problématiques ont été traitées pour permettre de comprendre l'impact et l'influence d'une politique de remanufacturation sur les performances d'un système de production. En effet, dans un premier temps, nous nous sommes intéressés à des systèmes de production composés d'une seule machine. Dans ce cadre, nous avons proposé des études séquentielles puis intégrées pour optimiser la politique de maintenance et celle de l'approvisionnement hybrides en pièces de rechange destinées aux actions de remplacements. Nous avons étudié également la gestion de production soumise à une contrainte de qualité basée sur l'évolution de la dégradation de la machine. Ensuite, et dans un second temps, nous avons présenté des généralisations des modèles étudiés dans le cadre de systèmes de production composés de plusieurs machines. Enfin, nous avons développé un outil d'aide à la décision pour conception de systèmes de production dans le cadre d'une politique de remanufacturation. Cette problématique - du niveau stratégique - vise à sélectionner le meilleur ensemble de machines pour construire un nouveau système de production capable de satisfaire les contraintes de production définies par décideur

National audience; Le présent article a pour objectif d'identifier les secteurs créateurs d’emplois à l’aide de l’analyse input-output en calculant les multiplicateurs d’emploi. Cette analyse permet de simuler l'impact de développement des différents secteurs de l’économie marocaine sur la création d'emploi. Ainsi, l'adoption de politiques sectorielles créatrices de richesses et d’emplois s’avère nécessaire pour remédier à la problématique du chômage au Maroc. Pour ce faire, il convient de mettre en place une stratégie pour la promotion de la croissance économique et la création d'emplois à travers l'investissement dans les secteurs créateurs d’emplois. Les principaux résultats de cette étude montrent que les investissements doivent s'orienter vers les industries de "raffinage de pétrole et autres", les industries "alimentaire et tabac", les industries "chimique et parachimique" et les industries "mécanique, métallurgique et électrique" qui ont des multiplicateurs d’emploi très élevés, mais sans négliger le secteur des "bâtiments et travaux publics", le secteur de "transports", le secteur d’"agriculture, chasse et services annexes" et le secteur de la "pêche, aquaculture" car ils ont un emploi direct très élevé.

International audience; In this paper, we consider the problem of scheduling a set of n jobs on two identical machines with preparation constraints. Each job requires before its execution a set of resources and a non-negligible preparation time. The objective is to minimise the makespan. This problem is NP-hard. We prove the NP-hardness of two specific cases where in the first case preparation times take only three values, whereas in the second case preparation times and the release dates take only two values, respectively. Then, we present some special cases and heuristic algorithms along with an experimental study.

International audience

This paper considers a condition-based maintenance policy for a system composed of m independent machines deteriorating system. Each machine is subject to stochastic degradation. The machines are maintained by spare parts provided either from supplier or from the remanufacturing centre. Three thresholds are used in our CBM policy, two for the corrective and preventive replacement and one for the order management. A new heuristic is proposed under two versions to calculate the sequential non-periodic inspection dates. A numerical example is presented to compare the proposed methods.

In this paper we propose a new heuristic based approach to determine the optimal non-periodic inspection plan on a finite time horizon for a condition-based maintenance. The considered system consists of a single machine subject to a continuous, monotonous and stochastic degradation which can lead to failure and consequently to a maintenance action. The maintenance actions consist of replacing the main part of the production unit by another spare part. Spare parts are classified by their degradation into several qualities: New spare parts, which are provided by external supplier with a fixed delivery time. Used spare parts which are collected and provided by the maintenance service with fixed remanufacturing time, Depending on decision thresholds, the replacement might be either preventive or corrective. The objective is to determine the order/remanufacturing decision threshold (from which an order/remanufacturing is to be launched) and the preventive maintenance decision threshold to perform the preventive replacement. Our approach aims to minimize the total cost due to replacement, storage, inspection, order/remanufacturing costs and downtime penalty. A simulation-based genetic algorithm is proposed. At the end numerical examples are given to observe the performance of the proposed heuristic.

This PhD thesis was focused on the study of cascade reactions and allowed the access to a large variety of polycyclic compounds. The extension of several methods employing palladocatalyzed cascade reactions and their limits have been studied. Those cascades are initiated by a 4-exo-dig cyclocarbopalladation, followed by a Sonogashira coupling. With an adequate substrate and the appropriate conditions, the cascade reaction can even be extended by an alcynilation, followed by an eight p electron electrocyclization and a six p electron electrocyclization. Complex scaffolds are thus obtained in only a few steps: fenestradienes and cyclooctatrienes. Derivatives with various substituents in different positions have been synthesized, particularly with heteroatoms. Their access has been ensured by either linear synthesis or a platform approach. This project was completed by an in silico study of the scaffolds regarding their drug-like potential.; Ces travaux de thèse nous ont permis de mettre en évidence un accès à un large nombre de composés polycycliques. Les étendues des méthodes employant des cascades réactionnelles palladocatalysées et leurs limites ont été étudiées. L’initialisation de ces cascades se fait par une cyclocarbopalladation de type de 4-exo-dig, suivie par un couplage de Sonogashira. Avec des substrats et des conditions adéquats, la cascade réactionnelle continue avec une alcynilation, une électrocyclisation à huit électrons p et une électrocyclisation à six électrons p. En un nombre limité d’étapes sont ainsi obtenus des châssis moléculaires complexes : les fenestradiènes et les cyclooctatriènes. Des dérivés portant des substituants variés dans différentes positions ont été synthétisés, notamment possédant des hétéroatomes. Leurs accès a été assuré par des synthèses linéaires ou encore par une approche plateforme. Ceci a été complété par une étude in silico en vue du potentiel thérapeutique de ces châssis moléculaires.

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The High-Atlas Mountainous region in Morocco is a true Water tower for the neighbouring arid plains, where the water resources at e intensively and increasingly Subjected to exploitation for agriculture and tourism In order to manage this resource sustainably, it is necessary to describe accurately all the processes that contribute to the hydrological cycle of the area. and, in particular, to know the respective contributions of liquid and solid precipitations to runoff In this context, a seven-year time series of SPOT-VEGETATION images is used for mapping snow-covered areas The spatial and temporal variations of the snow cover are analyzed for the entire High-Atlas region as well as by altitudinal zones The spatial distribution of snow-covered areas appears logically controlled by elevation. and its temporal fluctuations can be clearly used to identify dry and wet seasons In addition, a possible control of snowfalls by the Northern Atlantic climate variability, and, in particular, the North Atlantic Oscillation, is highlighted Finally, this Study Shows how satellite remote sensing can be useful for the long-term observation of the intra- and inter-annual variability of snowpacks in rather inaccessible regions where the network of meteorological stations is deficient (C) 2009 Elsevier B V All rights reserved

In the centre of Morocco, the High Atlas mountain range represents the most important water storage for the neighbouring arid plains through liquid and solid precipitation. In this context, we evaluated the performance of the Snowmelt Runoff Model (SRM) on the five main tributary watersheds of the High Atlas range. Due to the very low density of climate stations in the High Atlas, snowfall and snowmelt processes are difficult to monitor using meteorological data alone. In order to compensate for the lack of in situ data, snow maps are also derived from remotely-sensed data. We compared the streamflow forecasting performance when the model is driven by one or the other estimate of snow-covered area. Both estimates are generally comparable in all watersheds, and satisfactory streamflow simulations were obtained at seasonal time scales using both snow-cover products. However, significant differences can be observed for selected storms, with more accurate streamflow predictions being obtained when the remotely-sensed data are used.

International audience; Recent efforts have been concentrated in the development of models to understand and predict the impact of environmental changes on hydrological cycle and water resources in arid and semi-arid regions. In this context, remote sensing data have been widely used to initialize, to force, or to control the simulations of these models. However, for several reasons, including the difficulty in establishing relationships between observational and model variables, the potential offered by satellite data has not been fully used. As a matter of fact, a few hydrological studies that use remote sensing data emanating from different sources (sensors, platforms) have been performed. In this context, the SUDMED programme has been designed in 2002 to address the issue of improving our understanding about the hydrological functioning of the Tensift basin, which is a semi-arid basin situated in central Morocco. The first goal is model development and/or refinement, for investigating the hydrological responses to future scenario about climate change and human pressure. The second aim is the effective use of remote sensing observations in conjunction with process models, to provide operational prognostics for improving water-resource management. The objective of this paper is to present the SUDMED programme, its objectives, and its thrust areas, and to provide an overview of the results obtained in the first phase of the programme (2002-2006). Finally, the lessons learned, future objectives, and unsolved issues are presented.