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Infrastructure Networks and Major Transportation Places in the World: A Geohistorical Perspective
No full textInternational audienceTransportation infrastructure networks are made up of a succession of lines and access points, generally characterized by a high level of attractiveness due to their ability to articulate different scales: local, regional and even global. This chapter proposes a diachronic approach to transportation infrastructure networks, tackled through the prism of modes of supply production and their technical structure. Structuring transportation networks are largely intangible: container shipping lines, freight and traveler airlines, internet lines using submarine and underground cables, fiber optics, satellite connections, etc. Three main innovations in transportation and communication technology are particularly associated with the current phase of globalization: container shipping, air transportation and the Internet. Over centuries, network-related innovations have repeatedly led to a “speed revolution”, resulting in major changes in the relationship with time and space. The geography of dominant transportation places reveals critical access points and lines both internationally and locally
La crise du Reform Bill, 1830-1832
No full textInternational audienceIn only two years, from 1830 to 1832, the House of Commons passed a substantial reform of parliamentary representation which had been unsuccessfully demanded by radicals since the 1760s. For Whig historians, the adoption of the 1832 Reform Act was a triumph for gradual reform orchestrated by the MPs themselves. On the contrary, “History from below” emphasises the external pressure exerted by the people on the ruling elite. Since the late 1990s, social history has moved away from Whig or Marxist narratives articulated around moments of rupture. It has stressed continuities while paying attention to changes in social identities and practices in all classes of society, in the cities and in the countryside. This article traces the unfolding of intra- and extra-parliamentary events to examine the significance of this seminal moment in British political history.En deux ans, de 1830 à 1832, la Chambre des communes a adopté une réforme de la représentation parlementaire qui était réclamée sans succès par les radicaux depuis les années 1760. Pour l’historiographie whig, il s’agit du triomphe d’un réformisme graduel piloté par les députés eux-mêmes. Les analyses de « l’histoire par le bas » mettent au contraire l’accent sur la pression externe exercée par le peuple sur les élites politiques. Depuis la fin des années 1990, l’histoire sociale s’est écartée des grands récits fondateurs articulés autour de moments de rupture, que ces récits soient whigs ou marxistes. L’accent est mis sur les continuités, mais surtout sur les évolutions des identités sociales et des pratiques, à la fois dans les villes et dans les campagnes. Cet article retrace le déroulé des événements intra- et extra-parlementaires et varie les focales dans l’analyse de ce moment fondateur de l’histoire politique britannique
Geochemical variation of intraplate magmatism and its sources in the Kaapvaal craton (Southern Africa) from Paleoarchean to present: implications for the evolution of its mantle lithosphere.
No full textInternational audienceThe Kaapvaal craton, which hosts rocks as old as 3.6 billion years, began to stabilize around 3.2 billion years ago with the progressive development of its subcontinental lithospheric mantle (SCLM). This craton, which has undergone continuous and relatively well-preserved geological evolution through numerous episodes of erosion, sedimentation and magmatic additions, provides a unique setting for studying the evolution of geodynamics. This study focuses primarily on the interpretation of existing literature and some newly acquired data for HFSE, REE and Lu-Hf and Sm-Nd isotopes, due to their immobility during low temperature alteration processes.The Palaeo-Mesoarchean transition marks significant changes in both geodynamic (from vertical to transitional tectonics) and magmatic processes. During this period, magmatism changed from mixed calc-alkaline and tholeiitic affinities derived from 'asthenospheric' sources to a pure tholeiitic series stemming from the (proto-)SCLM and/or asthenosphere. Almost all Meso- and Neoarchean igneous units show 'arc-like' geochemical signatures (e.g., negative Nb, Ta and Ti anomalies), mainly due to crustal assimilation. Only a few occurrences may reflect clear fluid metasomatism of the mantle sources. A major shift occurred in the early Paleoproterozoic, characterized by a protracted magmatic phase lasting over 500 Myr, with events showing significantly high Th/Nb ratios. These signatures are likely to be from refertilized sources, linked to a major metasomatic event and hence a significant but transient subduction (or comparable) process at the Archean-Proterozoic transition. After 1830 Ma, the frequency of magmatism decreases significantly, leaving only three major events (at ~1400, 1100 and 180 Ma), if we except kimberlites and lamproites. During this time, the Kaapvaal craton gradually evolved into a component of larger continental masses (i.e., proto-Kalahari then Kalahari cratons). However, these post-Paleoproterozoic events show much more diverse magmatic source signatures than earlier periods, including contributions from previously unobserved sources (e.g., OIB-like or enriched mantle OIB).The data suggest that most (but not all) post-Paleoarchean magmatic events are associated with plume-related activity involving melting of the SCLM at shallow depths (i.e., spinel mantle), consistent with conclusions from previous studies that considered these events separately. However, a relatively inert Late Mesoarchean SCLM alone would not be sufficient to generate such widespread and long-lasting magmatic activity, particularly if it exhibits enriched geochemical signatures. Overall, the geochemical data support an evolving SCLM that underwent periods of (local) melting, depletion and refertilization
Self-adaptive single-diode model parameter identification under small mismatching conditions
No full textInternational audienc
Éprouver les méthodologies pour accompagner les transitions Experiencing methodologies to support transitions
No full textInternational audienceThis contribution examines how information and communication sciences contribute to the "digital transition" by questioning the scientific and operational reliability of the methods used by consulting firms to test "innovative solutions" in support of the transition. Supporting transitions requires pluri- and/or interdisciplinary cooperation between academic and non-academic actors. The objective of this article is to uncover the communicational, semiotic, and affective blind spots in these studies. More specifically, we focus on the lack of consideration given to semiotic choices in configuring affective relationships with innovation. Our aim is to demonstrate, in line with established research in ICS, that design choices condition the understanding of added value, particularly in affective terms. Evaluation is a matter of valuation (Dewey, 1939), yet this dimension remains an overlooked aspect of reception studies.Cette contribution examine comment les SIC participent à la « transition numérique », en interrogeant la fiabilité scientifique et opérationnelle des méthodes utilisées par les bureaux d'études de test de "solutions innovantes" au service de la transition. Accompagner les transitions implique des coopérations pluri-et/ou interdisciplinaires entre académiques et non académiques. L'objectif de cet article est de révéler les impensés communicationnels, sémiotiques et affectifs, dans les études réalisées. Ce qui nous occupe plus précisément est la non prise en compte des choix sémiotiques en termes de configuration des relations affectives à l'innovation. Notre propos est de démontrer, dans la continuité des acquis en SIC, que les choix de conception conditionnent la compréhension de la valeur ajoutée, en particulie
La production d’écrits à partir d’albums sans texte en classe de CP
No full textDans quelle mesure les albums sans texte peuvent-ils constituer un support pédagogique pertinent pour accompagner les élèves de CP dans l’apprentissage de la production écrite ? Et de quelle manière les albums sans texte peuvent-ils favoriser l’entrée en production écrite ? À travers l’analyse de la mise en place d’un travail de production écrite à partir d’un album sans texte, il s’agit de comprendre l’étendue de l’impact de ce support pédagogique sur l’écriture des élèves de CP. C’est pour cette raison que ce mémoire rend compte des différentes recherches sur les enjeux et les difficultés de la production écrite en CP, mais également des recherches sur les albums sans texte ainsi que leurs possibles mises en pratiques pédagogiques. Dans l’étude réalisée pour ce mémoire, nous avons pu établir que l’album sans texte est un élément déclencheur de l’écriture
Energy Efficient and Delay-Guaranteed User Association Algorithm for O-RAN
No full textInternational audienceOpen radio access network (O-RAN) is one of the key solutions envisaged to meet the ever increasing and stringent quality of service (QoS) demands of emerging applications and services supported by beyond 5G networks. In addition to meeting these QoS demands, O-RAN also promotes vendor diversity and interoperability by disaggregating the radio access network (RAN) into different units, namely the central unit (CU), distributed unit (DU), and radio unit (RU). However, the disaggregation introduces a new challenge of ensuring seamless interoperability between the various units with a view to ensuring that the QoS of the user equipments (UEs) is met and the energy consumption of the system is managed efficiently. In this paper, we focus on jointly optimizing UE association and RU energy consumption. We express the problem as an optimization problem and propose a scheme that determines the optimal RU among potential RUs that a UE should be associated to while minimizing the total used RUs. Moreover, we employ a power control mechanism that enables idle RUs without associated UEs to be put in sleep mode. To show the efficiency of the proposed algorithm, we evaluated it against some state of the art (SoA) solutions. The results indicate that the proposed solution minimizes energy consumption by about 171% and 32% under low and high number of UEs, respectively, while incurring a paltry 3.2% increase in access network delay for UEs without violating their delay requirements.</div
Asymmetric Intramolecular α‐Arylation of Polar Amino Acids Bearing β‐Leaving Groups
No full textInternational audienceAbstract The α‐arylation of amino acids may be achieved by intramolecular nucleophilic aromatic substitution (S N Ar) reactions of amino‐acid derived enolates, but for amino acids bearing β‐leaving groups, such reactions are complicated by competing E1cB elimination of the β‐substituent. In this paper we report an approach to the arylation of the polar amino acids serine, cysteine, diaminopropionic acid, and allothreonine by inducing intramolecular S N Ar reactions of heterocycles, which the heteroatom substituent is stereoelectronically protected from elimination by incorporating it into the ring system of N ‐carbamoyl oxazolidines, thiazolidines, or imidazolidines. The sequence comprises the diastereoselective formation of a heterocyclic urea followed by an intramolecular N‐to‐C aryl migration, yielding bicyclic hydantoins that can be further hydrolysed to afford quaternary α‐aryl amino acids. The method is practical and scalable, avoids the use of transition metals or chiral auxiliaries, and provides the opportunity to access a variety of α‐arylated products bearing electronically diverse benzenoid or heterocyclic substituents (35 examples)
L'école primaire comme acteur de prévention des violences sexuelles : intérêt de l’Éducation à la Vie Affective, Relationnelle et Sexuelle (EVARS) sur la capacité des enfants à se protéger. Mise en place de cours d’Éducation à la Vie Affective, Relationnelle et Sexuelle en CM2
No full textCe mémoire interroge le rôle de l’école primaire dans la prévention des violences sexuelles faites aux enfants, en prenant appui sur des séances d’éducation affective et sexuelle menées en classe de CM2. L’objectif est de déterminer dans quelle mesure un enseignement structuré autour de la connaissance de soi, du respect d’autrui et de la notion de consentement peut renforcer chez les élèves leur capacité à identifier et à se protéger d’éventuelles situations de violences sexuelles dans leur sphère privée. Le cadre théorique s’appuie sur les approches pluridisciplinaires combinant sciences de l’éducation, psychologie du développement et sociologie de l’enfance, tout en tenant compte des textes officiels (circulaires, programmes scolaires) qui légitiment et encouragent l’intervention de l’école en matière de prévention et de promotion du respect. Une méthodologie qualitative a été retenue : observations de classe, entretiens semi-directifs avec des enseignants et une psychologue. Les données collectées éclairent tant les leviers que les freins institutionnels, pédagogiques et socioculturels affectant la mise en place d’un dispositif d’éducation à la vie affective, relationnelle et sexuelle. Les résultats montrent que des séances d’information et d’échanges, progressives et adaptées à l’âge des enfants, renforcent leur compréhension du corps, du consentement et des moyens de demander de l’aide en cas de situation à risque. Toutefois, des obstacles apparaissent, notamment le manque de formation des enseignants, la crainte de réactions parentales et le tabou persistant autour de la sexualité à l’école. L’étude conclut sur l’importance d’une approche globale de prévention dans les politiques éducatives, en soulignant que la sensibilisation précoce –portée par des adultes formés et soutenus– constitue un levier essentiel pour protéger les enfants de violences encore trop souvent invisibles
Quantized Object Detection for Real-Time Inference on Embedded GPU Architectures
No full textInternational audienceDeploying deep learning-based object detection models like YOLOv4 on resource-constrained embedded architectures presents several challenges, particularly regarding computing performance, memory usage, and energy consumption. This study examines the quantization of the YOLOv4 model to facilitate real-time inference on lightweight edge devices, focusing on NVIDIA’s Jetson Nano and AGX. We utilize post-training quantization techniques to reduce both model size and computational complexity, all while striving to maintain acceptable detection accuracy. Experimental results indicate that an 8-bit quantized YOLOv4 model can achieve near real-time performance with minimal accuracy loss. This makes it well-suited for embedded applications such as autonomous navigation. Additionally, this research highlights the trade-offs between model compression and detection performance, proposing an optimization method tailored to the hardware constraints of embedded architectures