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A small polymerase ribozyme that can synthesize itself and its complementary strand
No full textInternational audienceThe emergence of a chemical system capable of self-replication and evolution is a critical event in the origin of life. RNA polymerase ribozymes can replicate RNA, but their large size and structural complexity impede self-replication and preclude their spontaneous emergence. Here, we describe QT45, a 45-nucleotide polymerase ribozyme, discovered from random sequence pools, that catalyzes general RNA-templated RNA synthesis using trinucleotide triphosphate (triplet) substrates in mildly alkaline eutectic ice. QT45 can synthesize both its complementary strand using a random triplet pool at 94.1% per-nucleotide fidelity and a copy of itself using defined substrates, both with yields of ~0.2% in 72 days. The discovery of polymerase activity in a small RNA motif suggests that polymerase ribozymes are more abundant in RNA sequence space than previously thought
Visualization of surface wave generation and tail wave formation in acoustic Wood anomalies
No full textInternational audienceAcoustic Wood anomalies are phenomena characterized by sharp amplitude peaks and dips at specific frequencies in the spectra of the waves reflected from periodic surfaces. Theoretical studies proposed the double mode conversion theory, suggesting bulk waves convert to surface waves at periodic rough surfaces and reconvert to bulk waves, which then interfere with specular reflections (main waves) as delayed reflected components (tail waves). However, experimental validation remains incomplete. This study clarifies the relationship between surface waves and tail waves through visualization of wave propagation processes and identifies causes of changes in tail wave formation due to periodic surface geometry. Pulse-echo experiments were conducted using carbon steel specimens with rectangular periodic profiles of varying pitch and depth. Finite-difference time-domain simulations visualized ultrasonic wave propagation under identical experimental conditions. Simulation data showed good agreement with experimental data, validating the simulation approach. Amplitude spectral analysis revealed that the surface waves and tail waves had common frequency characteristics, confirming the double mode conversion assumption. The simulations successfully visualized surface waves generation, propagation, and reconversion to bulk waves, demonstrating tail wave formation from surface waves in detail
LE PROJET «PARI » La datation des glissements de terrain islandais et leur rôle dans l’évolution des paysages
No full textRapport d'activité de l'IPEVLe projet PARI 1266 (PAraglacial Rock-Slope failures dating in Iceland), financé par l’Institut polaire de 2022 à 2025, a pour objectif de dater les glissements de terrain postglaciaires dans les Westfjords islandais et de comprendre leur rôle dans l’évolution des paysages à la fin de la dernière grande glaciation autour de 10 000 ans. Après l’inventaire des dépôts de glissements de terrain aboutissant à une cartographie, un travail de terrain a mobilisé des méthodes de description et de quantification des volumes déposés et de datation (recherches d’éléments datables au carbone 14 dans les séquences sédimentaires, utilisation du marteau de Schmidt). Les résultats obtenus montrent que les glissements de terrain se mettent en place dans les premiers millénaires après le départ des glaciers et que les volumes mobilisés (des millions de m3) au cours de cette crise géomorphologique paraglaciaire contribuent à l’élargissement des vallées glaciaires. Cette ampleur des instabilités passées des versants permet de comprendre les écroulements actuels des parois dans les massifs montagneux de la planète
L’énigme du calice dans Bouvard et Pécuchet
No full textInternational audienceQuelques jours avant de mourir le 8 mai 1880, Gustave Flaubert élaborait l'épisode sur la botanique, un des derniers de son roman Bouvard et Pécuchet. À cette fin, et inspiré par une phrase de Rousseau sur le calice des fleurs qui « manque à la plupart des liliacées », il avait rédigé une note en forme d'énigme botanique : trouver une plante commune, poussant en Normandie au mois d'avril, qui serait d'une famille qui dérogerait à une règle générale chez les plantes (« Toute plante a des feuilles, un calice et une corolle »), mais qui elle-même dérogerait à cette exception au sein de sa famille (une exception à l'exception). Sans grande familiarité avec la botanique, Flaubert prétendait prédire l'existence d'une telle plante, alors que l'énigme suscitait la circonspection chez ses amis plus savants. Une enquête de Maupassant lui a permis d'examiner des solutions possibles d'abord parmi les Renonculacées puis les Rubiacées, où la shérarde lui a semblé répondre à son attente. Cet épisode laisse toujours plusieurs questions sans réponse, auxquelles nous tentons d'apporter des éclairages, qui nécessitent un regard botanique sur cette énigme : pourquoi Rousseau a-t-il écrit « la plupart » ? Pourquoi Flaubert a-t-il refusé la première solution de Maupassant ? Pourquoi a-t-il accepté la seconde ? La shérarde était-elle en 1880, et est-elle aujourd'hui une bonne solution à son énigme ? Quels mécanismes naturels ou épistémologiques, produisent les exceptions aux exceptions ? Comment cette plante imaginaire peut-elle devenir le terrain de confrontation de conceptions différentes de la nature et de la connaissance, du XIXe au XXIe siècle ? ABSTRACT. A few days before his death on May 8, 1880, Gustave Flaubert was working on the episode about botany, one of the last in his novel Bouvard and Pécuchet. To this end, inspired by a sentence by Rousseau about the calyx of flowers, which "is missing in most liliaceae," he wrote a note in the form of a botanical enigma: to find a common plant, growing in Normandy in April, that would belong to a family that deviated from a general rule among plants ("Every plant has leaves, a calyx, and a corolla"), but which itself would deviate from this exception within its family (an exception to the exception). Without much familiarity with botany, Flaubert claimed to predict the existence of such a plant, while the enigma aroused caution among his more knowledgeable friends. An investigation by Maupassant allowed him to examine possible solutions, first among the Ranunculaceae and then the Rubiaceae, where the sherardia seemed to meet his expectations. This episode still leaves several questions unanswered, which we will attempt to shed light on, requiring a botanical and historical perspective on this enigma: why did Rousseau write "most"? Why did Flaubert reject Maupassant's first solution? Why did he accept the second? Was the sherardia in 1880, and is it today, a good solution to his enigma? What natural or epistemological mechanisms produce exceptions to exceptions? How can this imaginary plant become the battleground for different conceptions of nature and knowledge, from the 19th to the 21st century
A comprehensive review on autonomous and plan-based QoS-aware service composition approaches in service community
No full textInternational audienceIn the evolving landscape of the Internet of Things (IoT), many smart devices provide basic functionalities as services that often fail to meet users’ requirements. To address this gap, fine-grained services are combined to create coarse-grained services, giving rise to the QoS-aware service composition challenge. The growing number of IoT devices has resulted in numerous fine-grained services with similar functional properties (inputs and outputs) but different non-functional properties, typically related to quality of service (QoS). The QoS-aware service composition approaches can be categorized into two main classes: plan-based approaches and autonomous ones. Existing surveys in this domain primarily focus on either a single class or technical aspects, such as composition representation and utility functions. In contrast, this study offers a comprehensive and systematic review of both classes, emphasizing resolution and validation methodologies. The contributions of this paper are fourfold: 1) introduce a novel taxonomy that classifies QoS-aware service composition approaches from the past decade based on their reliance on preexisting abstract composition plans, 2) provide a detailed comparative analysis of these approaches using the most relevant criteria in the service composition field, 3) investigate their resolution and validation methodologies along with the quality and appropriateness of the datasets used in the reviewed approaches, and 4) discuss future directions for advancing the field. This review not only bridges the knowledge gap in understanding these approaches but also serves as a foundation for researchers to develop more robust and efficient QoS-aware service composition methods
A Revision of the Quality Metrics of Physical Unclonable Functions
No full textInternational audiencePhysical unclonable functions (PUFs) leverage process variability to generate unique signatures in electronic devices. They are a strong alternative to conventional security mechanisms as they do not rely on non-volatile memories (NVMs) to store the secrets. However, PUFs can be influenced by external factors and may exhibit biased output distributions, leading to vulnerabilities that could compromise their uniqueness and resistance to cloning. The quality of a PUF is evaluated through a common set of metrics such as uniformity, bit-aliasing, uniqueness, and reliability. However, the lack of standardized methodologies hinders effective comparisons between diverse PUF designs, limiting the broader understanding of their performance. Besides, the underlying physics and mechanisms of PUFs makes them difficult to study and mitigate potential vulnerabilities and attacks. Overall, the quality metrics for PUFs are still evolving, and there is ongoing research to address these challenges and develop more robust and reliable PUFs. In this article, we demonstrate the limitations of current PUF evaluation metrics using experimental data and introduce a novel set of metrics that provide a more rigorous and comprehensive assessment.</p
Le Velin, un territoire sans patrimoines ?: Réflexion sur la notion d'« ordinaire » appliquée au champ patrimonial
No full textInternational audienceLe Velin, plus communément appelé « Plaine de l'Est lyonnais », est perçu comme un territoire sans identité, pour l'essentiel occupé par des zones pavillonnaires, logistiques et de lourdes infrastructures de transport. Espace d'expansion de l'agglomération lyonnaise, son bâti ancien est largement méconnu et fait encore moins l'objet de protections.La communication vise à mettre en lumière les processus production/dilution des identités territoriales et à interroger la pertinence du modèle de patrimonialisation institutionnelle pour faire reconnaître la valeur des héritages architecturaux des espaces ordinaires des territoires périurbains
Bis(monoacylglycero)phosphate protects murine RAW 264.7 macrophages against 7-Ketocholesterol-induced apoptosis and impaired autophagy
No full textInternational audienceAtherosclerosis, a leading cause of cardiovascular disease, is driven by the accumulation of oxidized low-density lipoproteins (oxLDL) in arterial walls. 7-Ketocholesterol (7KC), a major oxysterol found in oxLDL and atherosclerotic plaques, triggers multiple cell injuries including loss of lysosomal integrity, oxidative stress, apoptosis, and impaired autophagy in vascular cells. Bis(monoacylglycero)phosphate (BMP), also known as lysobisphosphatidic acid, is a unique phospholipid concentrated in the endolysosomal compartment, known to regulate vesicle dynamics, lysosomal enzyme activities, intracellular cholesterol trafficking and its oxidative metabolism. Using a validated model of BMP enrichment in murine RAW 264.7 macrophages, we investigated whether BMP could exert protective activity against 7KC-induced damage. Our findings revealed that BMP enrichment provides comprehensive protection against 7KC at the cellular level by preserving cell viability, morphology, and neutral lipid balance. Mechanistically, BMP enrichment prevented apoptosis by maintaining mitochondrial integrity and blocking caspase activation. This was demonstrated by normalized BAX/BCL2 ratios, preserved pro-Caspase-3 levels, and reduced PARP cleavage. Remarkably, BMP enrichment also restored autophagic flux, thereby preventing the pathological accumulation of LC3-II and p62 that characterizes autophagy dysfunction. Enhanced colocalization between LC3 and BMP suggests direct functional interactions in the stress response. Gene expression analysis confirmed that BMP enrichment normalized the transcriptional dysregulation of key autophagy regulators, including Sqstm1, Becn1, and Pink1. Taken together, these results suggest that BMP is an endogenous protective factor that counteracts 7KC-induced cellular damage at multiple steps by regulating cell death and autophagy pathways in a coordinated manner
Droit de la rénovation énergétique des bâtiments : état des lieux et perspectives
No full textNational audienceLa rénovation énergétique des bâtiments occupe une place nouvellement prépondérante dans l'actualité juridique. La stratégie publique qui en traite s'appuie sur des régimes juridiques fragmentés, sur des incitations victimes de l'instabilité budgétaire et de la complexité du parcours du particulier, et sur des obligations peu crédibles, nuisant à la dynamique souhaitée de massification. L'atteinte des objectifs visés nécessite un changement de paradigme, appréhendant le droit de la rénovation non pas comme un régime autonome mais comme un droit d'assemblage transversal et finaliste, dépassant l'ensilotage des politiques publiques, et s'inscrivant dans une logique de service public dont le but est de réussir le défi de la massification des rénovations
Que dévoile l’« elicitation-interview » ? Regards et paroles de personnes amputées engagées dans un dispositif filmique ethnographique
No full textInternational audienceThe “elicitation interview”’ is a an investigative method that combines discourse and (audio)visual media analysis. This process has been used during an ethnographic survey conducted within a peer-support association for amputees. Following the co-production of short films with members of the association about their experiences as amputees and prosthesis users, interviews were conducted with these same individuals after viewing and broadcasting the videos. This article examines how the use of « elicitation interview » has contributed to the production of ethnographic data and its analysis, and more generally, what this process has brought to the investigation. The first and the second parts of the article focus on the feedback from amputees involved in the audio-visual project and the contributions and effects of their participation. The third part analyses the ways in which these films were used in rehabilitation centres as part of peer support practices and their potential usefulness for people who have recently undergone amputation. The aim and scope of these films are finally discussed, in particular how they are ultimately not limited to amputees patients and can reach out to a wider audience.L’« élicitation interview » est une méthode d’enquête qui associe discours et support (audio)visuel. Ce procédé a été mobilisé au cours d’une enquête ethnographique menée au sein d’une association d’entraide réunissant des personnes amputées. Suite à la coréalisation de courts films avec des membres de l’association sur leurs vécues amputés et appareillés, des entretiens ont été menés avec ces mêmes personnes après visionnage et diffusion des vidéos. Basé sur ces entretiens, cet article étudie ce que l’usage de l’« élicitation interview » a permis quant à la production de données ethnographiques et à leurs analyses, et plus généralement ce que ce procédé a apporté à l'enquête. L’article examine d’abord les retours d’expériences des personnes amputées engagés dans le projet audiovisuel, ainsi que les apports et les effets liés à leur participation. Ensuite, ce sont les manières dont ils se sont servis de ces films en centre de réadaptation dans le cadre de pratique de soutien entre pairs et leurs possibles utilités pour les personnes récemment amputées qui sont analysées. Enfin, sont abordées la visée et la portée de ces films qui dépassent au final le seul public des personnes amputées pour s’adresser à un assistance plus large