Des comètes aux tempêtes : le brassage disciplinaire d’Hervé Faye, entre ruptures et continuités

À quoi Hervé Faye peut-il nous être utile ? En traversant une grande partie du XIXe siècle, Faye nous offre certainement la possibilité de porter un regard renouvelé sur la science d’une époque où les savoirs s’institutionnalisent, où des disciplines apparaissent sous l’influence de nouvelles techniques, où la société vit de profonds bouleversements sociaux et économiques. Personnage assez méconnu et peu étudié, Faye apparaît tout à la fois comme un acteur de ces nouveaux domaines de savoir q..

The Cybersecurity Aspects of New Entities Need a Cybernetic, Holistic Perspective

In our connected world security and proof (evidence constituted in Verifiable Credentials (VC, W3C)) is distributed over what an individual can attest, what my objects tell about me (that is why AI = inferences from that data, is so important), and my behavior: “apply shaving foam” is a number in coelition.org. It is clear that we can no longer isolate the notion of security as in securing devices or securing infrastructure. In this brief article which is the background to a number of workshops that the authors and the Journal will host together, we sketch what we believe to be the end of a paradigm of a government model that has outsourced capabilities to the market. It is in the process of privatizing its last public capability: identity management. This is causing tremendous stress in systems, services, organizational procedures, and individuals. We propose a holistic perspective, distributing security at two points: at the device level and a moral movement at a societal level. As a time out to create room to discuss this broadly, we propose a particular model of SSI and disposable identities

Introduction

Cet ouvrage rassemble les interventions de la journée d’études consacrée à Hervé Faye (1814-1902), le 26 septembre 2012. Organisée par le Groupe d’Histoire de l’Astronomie du Centre François Viète (GHACFV), au Muséum d’Histoire Naturelle de Nantes, cette journée a réuni une dizaine d’historiens des sciences qui ont réfléchi aux multiples facettes du personnage de façon à le saisir dans sa globalité, et ainsi éclairer certains aspects de la science française du XIXe siècle, tant d’un point de ..

Cellulose Nanocrystals: From Classical Hydrolysis to the Use of Deep Eutectic Solvents

During the last two decades, interest in cellulosic nanomaterials has greatly increased. Among these nanocelluloses, cellulose nanocrystals (CNC) exhibit outstanding properties. Indeed, besides their high crystallinity, cellulose nanocrystals are interesting in terms of morphology with high aspect ratio (length 100–1000 nm, width 2–15 nm), high specific area, and high mechanical properties. Moreover, they can be used as rheological modifier, emulsifier, or for barrier properties, and their surface chemistry opens the door to numerous feasible chemical modifications, leading to a large panel of applications in medical, electronic, composites, or packaging, for example. Traditionally, their extraction is performed via monitored sulfuric acid hydrolysis, leading to well-dispersed aqueous CNC suspensions; these last bearing negative charges (half-sulfate ester groups) at their surface. More recently, natural chemicals called deep eutectic solvents (DESs) have been used for the production of CNC in a way of green chemistry, and characterization of recovered CNC is encouraging

Evaluation of the level of prediction errors and sub-hourly variability of PV and wind generation in a future with a large amount of renewables

International audienceIn this paper we propose a method for the simulation of errors in renewable energy sources generation forecasting (photovoltaic and wind) for use in power system planning studies. The proposed methodology relies on 5 elementary simulation steps. The first step is the simulation of photovoltaic plant and wind farm power production, with a sufficient spatial and temporal resolution (few km and hourly time step), the second is the simulation of the localisation of production sites, the third step is the generation of forecast errors using historic data of numerical weather predictions, and the last step is the simulation of intra-hourly variations of photovoltaic production. Finally, it is discussed how these simulation tools can assist the evaluation of the required tertiary reserves in a power system with a large share of renewable energies into the mix

Aspects histologiques de l’anneau dural distal

L’Anneau distal dural (ADD) représente la zone du feuillet interne de la dure mère, traversée par l’artère carotide interne, au niveau du toit du sinus caverneux. Il se caractérise par une adhérence forte de la dure mère à la paroi vasculaire.Dans le but de décrire la microscopie de cette adhérence, nous avons mené une étude histologique dans les Laboratoires d’Anatomie et d’Histologie des Facultés de Médecine d’Amiens (France) et de Brazzaville (Congo), à partir de 36 ADD prélevés sur 18 têtes formolées.Cette étude a montré que la forte adhésion de la dure mère à la paroi de la carotide interne est due au fait que les fibres durales pénètrent dans la paroi artérielle jusqu’au niveau de la média.Ces résultats histologiques montrent les risques de blessure de la paroi carotidienne, que représente toute tentative de séparation de ces deux structures, lors de la chirurgie de cette région.Mots clés: Anneau distal dural - Artère carotide interne - Région para clinoïdienne - Traversée duraleEnglish Title: Histological features of the distal dural ringEnglish AbstractThe distal dural ring (DDR) is the area of the inner layer of the dura mater, through which the internal carotid artery at the level of the roof of the cavernous sinus. It is characterized by a strong adhesion of the dura to the vascular wall.In order to describe this microscopic adhesion, we performed a histological study in the Laboratory of Anatomy and Histology of Faculties of Medicine of Amiens (France) and Brazzaville (Congo), from 36 DDR taken heads of 18 formalin. This study showed that the strong adhesion of the dura to the wall of the internal carotid artery is due to the fact that the dural fibers enter the arterial wall to the level of the media.These histological results showed the risk of injury of the carotid wall, as is any attempt to separate these two structures during surgery in this region.Keywords: distal dural ring - para clinoid area -carotid crossing dura

Hervé Faye (1814-1902)

Cette chronologie non exhaustive rassemble des informations éparses, des évènements et faits inconnus ou méconnus jusqu’à présent, permettant au lecteur de se faire une idée générale du déroulement de la vie et de la carrière d’Hervé Faye. Le lecteur se reportera aux divers articles de ce volume pour le développement de tel ou tel aspect de son oeuvre. La bibliographie est construite sur l’inventaire de la BNF (Opale Plus) et ne prend en compte que les principaux ouvrages imprimés et les cour..

Effect of grain orientation and magnesium doping on β-tricalcium phosphate resorption behavior

The efficiency of calcium phosphate (CaP) bone substitutes can be improved by tuning their resorption rate. The influence of both crystal orientation and ion doping on resorption is here investigated for beta-tricalcium phosphate (β-TCP). Non-doped and Mg-doped (1 and 6 mol%) sintered β-TCP samples were immersed in acidic solution (pH 4.4) to mimic the environmental conditions found underneath active osteoclasts. The surfaces of β-TCP samples were observed after acid-etching and compared to surfaces after osteoclastic resorption assays. β-TCP grains exhibited similar patterns with characteristic intra-crystalline pillars after acid-etching and after cell-mediated resorption. Electron BackScatter Diffraction analyses, coupled with Scanning Electron Microscopy, Inductively Coupled Plasma–Mass Spectrometry and X-Ray Diffraction, demonstrated the influence of both grain orientation and doping on the process and kinetics of resorption. Grains with c-axis nearly perpendicular to the surface were preferentially etched in non-doped β-TCP samples, whereas all grains with simple axis (a, b or c) nearly normal to the surface were etched in 6 mol% Mg-doped samples. In addition, both the dissolution rate and the percentage of etched surface were lower in Mg-doped specimens. Finally, the alignment direction of the intra-crystalline pillars was correlated with the preferential direction for dissolution. Statement of significance: The present work focuses on the resorption behavior of calcium phosphate bioceramics. A simple and cost-effective alternative to osteoclast culture was implemented to identify which material features drive resorption. For the first time, it was demonstrated that crystal orientation, measured by Electron Backscatter Diffraction, is the discriminating factor between grains, which resorbed first, and grains, which resorbed slower. It also elucidated how resorption kinetics can be tuned by doping β-tricalcium phosphate with ions of interest. Doping with magnesium impacted lattice parameters. Therefore, the crystal orientations, which preferentially resorbed, changed, explaining the solubility decrease. These important findings pave the way for the design of optimized bone graft substitutes with tailored resorption kinetics