66 research outputs found

    The Middle Atlas Geological karsts forms: Towards Geosites characterization

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    International audienceRich limestone Jurassic formations and huge water reservoir are natural characteristics of the Middle Atlas Chain in Morocco, which, therefore, offers geodiversity of karst geosystems. The geological, tectonic and hydro-geo-morphological nature of the history of Atlas orogeny has affected the eastern part of the Middle, ensuring the evolution of karst features on various sites of this zone. This study presents some touristic offers specific to the Middle Atlas, particularly in terms of genesis, structures, and functions that could develop and promote public tourism offers. It argues that this development depends on future geological funds identification and classification as Geosites. On the basis of the patrimonial process characterising the Middle Atlas, this study suggests the creation of a Geopark in the Middle Atlas, within the framework of the evaluation criteria of the UNESCO. The implementation of this suggestion would contribute to the socioeconomic development of this region of Morocco

    Biomarqueurs d'imagerie fonctionnelle de la mémoire de travail au cours du vieillissement cérébral normal

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    Normal brain aging is characterized by a progressive decline in information processing ability in particular in the system of working memory. Therefore, it is essential to examine neural substrates underlying the working memory system which can be assessed by functional magnetic resonance imaging (fMRI). The aim of our work is to explore, in a large cohort of healthy elderly individuals, reorganizations in the networks in relation to (i) increase task load during a DIR (delayed item recognition) task, (ii) age during increase DIR task load and (iii) the performance in the DIR task during a resting state. Three hundred and eighty elderly participants (82 years, 56% women) from the Three-City cohort in Montpellier have been selected to perform an fMRI exam including a DIR task and a resting state. DIR task consisted of three phases: (i) stimulation – presentation of one, three or six letters - (ii) retention - blank screen to hold the stimulus items in mind - and (iii) probe - after the presentation of a target letter, the participant indicates whether or not this probe matched a letter in the study array. In the first work, using a covariance analysis, we observed, when the difficulty of the DIR task increases, simultaneously increased activation in salience and central executive networks during three phases separately of the DIR task and decreased activation in DMN during stimulation phase and in limbic regions and deep grey nuclei during retention phase. It may be hypothesized that salience and central executive networks interact in a complex way with DMN and limbic regions and deep grey nuclei. In the second work, age effects on load-dependent increases activations of the task were explored. Reduced activation in the left parietal lobe was identified in very old individuals compared to young old individuals during the stimulation phase suggesting an involvement of posterior–anterior shift with increasing age. In the third work, networks implicated in working memory (central executive, salience and the default mode networks) were highlighted by independent component analysis during the resting state. Our findings have confirmed that the functional connectivity and performance are related by: (i) a decreased in the both salience and the default mode networks and (ii) an increased in the central executive network. We can suggest that the decreased functional connectivity within the salience and the default mode networks could be due attentional and memory processes alterations and/or altered motivation. The increased functional connectivity within the central executive network could be related to compensatory mechanisms meanwhile elders would perform more poorly. All of these studies indicate that brain reorganizations of neural networks (salience, central executive and default mode) underlying working memory in normal brain aging.Le vieillissement cérébral normal est caractérisé par un déclin progressif de la capacité de traitement des informations en particulier dans le système de la mémoire de travail. Il apparaît donc essentiel d'explorer l'organisation corticale cérébrale sous-jacente au mécanisme de la mémoire de travail dont l'évaluation est rendu possible par l'imagerie par résonance magnétique fonctionnelle (IRMf). Les objectifs de notre travail ont consisté à identifier, dans une large cohorte d'individus âgés en bonne santé, les réorganisations des réseaux neuronaux en relation avec (i) l'augmentation de la difficulté d'une tâche de mémoire de travail, (ii) l'âge des individus au cours de la tâche et (iii) la performance de la tâche pendant un état de repos. Trois cent quatre-vingt participants âgés (82 ans, 56% femmes) issus de la cohorte des Trois Cités de Montpellier ont été sélectionnés pour réaliser un examen d'IRMf comprenant une tâche de DIR (reconnaissance d'item en élément différé) et un état de repos. La tâche de DIR s'organisait en trois phases : (i) présentation – une, trois ou six lettres – (ii) rétention – écran blanc – et (iii) réponse – après la présentation d'une lettre cible, le participant indique si cette lettre cible faisait partie ou non de l'ensemble de départ. Dans une première partie, après avoir localisé les régions activées lors des trois phases de la tâche, nos analyses de covariance ont pu identifier, simultanément à la difficulté croissante de la tâche, une augmentation de l'activation dans les réseaux du central exécutif et de saillance pendant les trois phases de la tâche ainsi qu'une diminution dans le réseau du mode par défaut pendant la phase de stimulation et dans les régions limbiques et des ganglions de la base pendant la phase de rétention. Ces résultats suggèrent une interaction entre les réseaux d'augmentation et de diminution. Dans une deuxième partie, nous avons exploré l'effet de l'âge sur l'augmentation de l'activité simultanément avec la difficulté croissante de la tâche. Pendant la phase de stimulation, une réduction de l'activation dans le lobule pariétal gauche a été identifiée chez les individus très âgés par rapport aux individus âgés jeunes suggérant la mise en jeu d'un décalage antéro-postérieur lorsque l'âge augmente. Dans une troisième partie, les réseaux impliqués dans la mémoire de travail (central exécutif, saillance et mode par défaut) ont été mis en évidence pendant l'état de repos. Notre travail a montré que la connectivité fonctionnelle et la performance sont corrélées par : (i) une réduction au sein des réseaux de saillance et du mode par défaut suggérant une altération des processus mémoriels et attentionnels et (ii) une augmentation au sein du réseau du central exécutif évoquant l'implication d'un processus compensatoire. L'ensemble de ces résultats indiquent la présence de réorganisations cérébrales des réseaux neuronaux (saillance, central exécutif et mode par défaut) sous-tendant la mémoire de travail au cours du vieillissement cérébral normal

    Morphotectonic evolution of the Jebel Bou Naceur in the South Middle Atlas Fault Zone (Morocco)

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    International audienceIn eastern Morocco, fault-related folds develop above the South Middle Atlas fault that separates the J. Bou Naceur 'pop-up' structure and the Missour Basin, filled with alluvial sediments. Using a combination of surfaces, field observations and digital topographic information, we have investigated several geomorphic criteria and geometry of depositional surfaces governed by the relief's growth. The propagation of the deformation is recorded by warped segmented fans that moved southeastward and wellpreserved geomorphological features of tectonic origin. Uplift of the anticline hinges and acceleration of valley incision since the Late Pliocene are considered a consequence of the ongoing NW-SE convergence between Africa and Eurasia. A scenario of morphotectonic evolution of this active mountain front is proposed

    CYBERSECURITY AND THE AUTOMOTIVE SUPPLY CHAIN IN MOROCCO: EXPLORATORY STUDY

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    Technological evolution exposes the Moroccan automotive supply chain to cyberattack risks, which could potentially lead to interruptions detrimental to operational continuity. In order to better understand the security measures currently in place to address these potential threats, an exploratory study was conducted within companies in the Moroccan automotive sector. This research was conducted through structured interviews, guided by specific questionnaires, with four carefully selected companies. The sample included two small and medium-sized enterprises (SMEs) as well as two large companies in the automotive sector in Morocco. The results obtained from these interviews reveal significant differences in the level of awareness and security approach towards cyberattack risks among the different companies interviewed. JEL: L91, L62, O33, D80, M15, R41  Article visualizations

    Localization and Mapping for Self-Driving Vehicles:A Survey

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    The upsurge of autonomous vehicles in the automobile industry will lead to better driving experiences while also enabling the users to solve challenging navigation problems. Reaching such capabilities will require significant technological attention and the flawless execution of various complex tasks, one of which is ensuring robust localization and mapping. Recent surveys have not provided a meaningful and comprehensive description of the current approaches in this field. Accordingly, this review is intended to provide adequate coverage of the problems affecting autonomous vehicles in this area, by examining the most recent methods for mapping and localization as well as related feature extraction and data security problems. First, a discussion of the contemporary methods of extracting relevant features from equipped sensors and their categorization as semantic, non-semantic, and deep learning methods is presented. We conclude that representativeness, low cost, and accessibility are crucial constraints in the choice of the methods to be adopted for localization and mapping tasks. Second, the survey focuses on methods to build a vehicle’s environment map, considering both the commercial and the academic solutions available. The analysis proposes a difference between two types of environment, known and unknown, and develops solutions in each case. Third, the survey explores different approaches to vehicles’ localization and also classifies them according to their mathematical characteristics and priorities. Each section concludes by presenting the related challenges and some future directions. The article also highlights the security problems likely to be encountered in self-driving vehicles, with an assessment of possible defense mechanisms that could prevent security attacks in vehicles. Finally, the article ends with a debate on the potential impacts of autonomous driving, spanning energy consumption and emission reduction, sound and light pollution, integration into smart cities, infrastructure optimization, and software refinement. This thorough investigation aims to foster a comprehensive understanding of the diverse implications of autonomous driving across various domains

    Contribución de las imágenes Landsat 8 OLI al mapeo de lineamientos y series litológicas: implicaciones para la exploración de mineralizaciones de Pb-Zn en el macizo de Boudahar, Alto Atlas oriental, Marruecos

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    The Boudahar massif is located in the southern part of the eastern belt of the Moroccan High Atlas and it corresponds to a reef mass of about ten kilometers in length. Jbel Boudahar is a district of lead-zinc-barite mineralization, known by a strong artisanal exploitation of its ores. This district is characterized by its topography with a contrast of altitude and an arid environment, which makes the information acquired more valuable. The processing of Landsat 8 OLI data allowed us to extract a lithological and structural map, aiming to make correlations to understand the distribution of lead-zinc mineralization. To this end, several tests were carried out, including the composition of color, principal component analysis and band ratio transformation. The location of the main deposits at Jbel Boudhar coincides well with the lineament derived from band 1 of principal component analysis and with the dolomitic pliensbachian formations mapped by MNF and BR from Landsat Oli8. A remote sensing geological prospecting model has been established for the Jbel Boudhar lead-zinc deposits, providing a basis for future prospecting of new deposits in a similar context.El macizo de Boudahar se encuentra en la parte sur del cinturón oriental del Alto Atlas marroquí y corresponde a una masa arrecifal de unos diez kilómetros de longitud. Jbel Boudahar es un distrito de mineralización de plomo-zinc-barita, conocido por una fuerte explotación artesanal de sus minerales. Este distrito se caracteriza por su topografía con contrastes de altitud y ambiente árido, lo que hace más valiosa la información obtenida. El procesamiento de datos Landsat 8 OLI nos permitió extraer un mapa litológico y estructural, con el objetivo de realizar correlaciones para entender la distribución de la mineralización de plomo-zinc. Para ello se realizaron varias pruebas, entre ellas la composición de color, análisis de componentes principales y transformaciones de ratios de bandas La ubicación de los depósitos principales en Jbel Boudhar coincide bien con el lineamiento derivado de la banda 1 del análisis de componentes principales y con las formaciones dolomíticas pliensbachienses mapeadas por MNF y BR de Landsat OLI8. Así, se ha establecido un modelo de prospección geológica de detección remota para los depósitos de plomo y zinc de Jbel Boudhar, que proporciona una base para la prospección futura de nuevos depósitos en un contexto similar. The processing of Landsat 8 OLI data allowed us to extract lithological and structural data in the Boudahar region, and to make correlations to understand the repartition of lead-zinc mineralization. Several tests were performed, including Color Composite, main component analysis, and band rationing transformation. These results assign high precision to the mapping process using remote sensing, and provide a clear relationship regarding lineaments and lithology, which control the repartition of Boudahar massif mineralization’s

    Impact de la néotectonique quaternaire sur la dynamique sédimentaire du Saïs (Maroc) : du bassin d'avant fosse pliocène au plateau continental quaternaire

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    Au passage du Néogène au Quaternaire, la région du Saïs a connu un changement important dans l’évolution géodynamique, marqué par une intense activité néotectonique qui a permis un changement radical de la géomorphologie du Saïs. Notre étude a permis de retracer l’histoire géologique de cette région depuis le Néogène.– Au Miocène supérieur, le Saïs correspond à un bassin marin d’avant fosse lié au sillon sud rifain situé à la limite sud du Prérif en cours de surrection. Son comblement se fait par des faciès marins profonds. Il s’agit d’une séquence majeure de dépôts essentiellement marneux à intercalations de turbidites lenticulaires gréseuses. La régression du Pliocène inférieur et moyen permet le dépôt de faciès paradeltaïques marquant ainsi les derniers dépôts marins dans le bassin du Saïs.– Au Pliocène terminal, le Saïs, ainsi comblé, forme un bassin endoréique correspondant à un palier simple sur le profil du paléofleuve de Sebou qui l’alimente. Nous avons situé l’exutoire du PaléoSebou dans la partie est du bassin, au droit de la ville de Fès. La sédimentation est détritique terrigène de type fluviatile sur les bordures du bassin. Elle est carbonatée et évaporitique de type lacustre au centre du bassin.– Au Quaternaire, on observe un changement radical dans l’évolution du Saïs. Il s’agit de la réactivation néotectonique majeure du front sud rifain et des flexures du Moyen Atlas traduisant ainsi une phase de compression N-S à NNW-SSE. Cette phase a permis la création de nouveaux reliefs sur les bordures du Saïs et la surélévation de ceux préexistants. Le système de rampes du front sud rifain permet le chevauchement, vers le sud, des rides de Zalagh et de Tghat sur les formations pliocènes du Saïs. Notre travail montre pour la première fois que le Saïs n’est plus un bassin situé entre deux chaînes, mais plutôt un plateau surélevé attaché au versant nord de la chaîne du Moyen Atlas. De ce fait, le drainage du réseau hydrographique se fait, désormais, du sud vers le nord perpendiculairement à la direction générale du Saïs. Les formations du Pliocène et leur substrat miocène subissent une érosion intense qui se traduit par des incisions dépassant les 100 m. Actuellement, la plaine de Saïs correspond à la partie médiane du bassin versant de Sebou située entre la partie amont dans le Moyen Atlas et le point bas exutoire situé dans le Prérif et la plaine du Gharb.Le passage du Pliocène au Quaternaire est marqué par une nouvelle phase tectonique qui a permis un changement radical dans la géomorphologie du Saïs et de ses bordures atlasiques et rifaines.Saïs is located between Rif and Middle Atlas chains; its Quaternary evolution corresponds to an inversion in dynamics compared to its evolution in Miocene and Pliocene times. We defined three major stages: – Upper Miocene: the Saïs is a foreland deep marine basin located at the southern limit of Pre-Rif during its uplift. The sequence includes more than 1 km of marls with interbedded turbidite sands. The structural style analysis shows that NE and NW extensional faults are responsible for graben formation towards the Saïs basin centre. This extensional system is contemporary with an advance towards the south of preriffian ridges ramps existing in the northern part of basin. The simultaneity of the extensive and compressive structures is typical of the foreland basins. The last marine deposits in the Saïs basin are littoral and paradeltaic sandy marls. The ultimate filling in Saïs basin, of Lower and Middle Pliocene age, is due to the marine regression in the South riffian basin.– Upper Pliocene evolution: the Saïs basin, thus filled, formed a continental basin corresponding to a simple stage on profile of the Sebou palaeoriver. We define the discharge system of PalaeoSebou in the eastern part of basin near Fez. Sedimentation is dominated by conglomerates of fluvial origin on the edges of the basin; it is evaporatic and lacustrine carbonate towards the basin centre. The climate was hot and humid. The northern part of the basin shows a syntectonic character expressed by flexural faults that affected the fluvial conglomerates. This deformation reflects an episode of mobilization of the preriffain ridges ramp of Tghat and Zalagh. – Quaternary evolution: The culmination of Saïs area is made by the progress of preriffian ramp who overrides on Pliocene deposits of the northern edge of Saïs. The preriffian ridges migrate towards the south by Zalagh, Sebou and Sidi Hrazem ramps. The southern riffian front “FSR” towards the south in the plain reorganized a change of course of the Sebou palaeoriver. This deformation translates NS to NNW-SSE compressional strain and allows reactivation of the preexisting Miocene structures and the neo-formation of new structures. A change in the evolution of Saïs results also of major neotectonic reactivation of the flexures of North Middle Atlas. This new structural state allows the rise of the Saïs who becomes elevated plain related to the northern middle atlasic catchment basin. Saïs Pliocene formations and their Miocene substrate are subjected to intense erosion whith fluvial incisions exceeding 100 m. Currently, the Saïs plain corresponds to the median part of the Sebou catchment basin located between the middle Atlas upstream and Prerif downstream. This last paroxysmal strain has been also described in the Pre-Rif (Faugères, 1978; Ait Brahim&Chotin, 1983; Chalouan et al., 2000, 2003) and in the south of Middle Atlas (Charroud 2002; Charroud et al., 2006). It is interpreted as being the result of the crustal readjustment under Alboran, Rif and Atlas (Frizon de Lamotte et al., 2004), where shoshonitic volcanism produced in the eastern external Betico-Riffian zones is replaced by the alkaline volcanism (Calvert et al., 2000). The role of crustal readjustment to explain the culmination of Saïs is proven for atlasic chain (Teixell et al., 2003; Arboleya et al., 2004; Ayarza et al., 2005)

    Environmental Management and its Impact on Psychosocial Health in Industrial Companies

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    Nowadays, Morocco keeps showing several efforts as part of sustainable development to introduce environmental management measures within companies, no matter what their size or activity field. However, studies prove the impact of these measures on psychosocial risk management which are still limited or inexistent. This paper explores the impact of poor environmental management as a factor affecting health and psychosocial well-being at work. The question is: How can environmental practices contribute to reducing psychosocial risks in the workplace? To answer this question, an experiment including the distribution of a questionnaire was carried out, addressed to 150 employees working in industrial companies in the Larache’s region, Morocco. The collected responses show that the psychosocial health of more than ninety percent of those surveyed is directly impacted by living conditions at work. These results indicate that responsible environmental management practices are necessary to improve employee well-being and reduce psychosocial risks in organisations
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