Imprimeur et graveur à la Belle Époque

L’exposition qui se tient actuellement au Musée de Montmartre, sous le commissariat général de Phillip Dennis Cate, nous fait découvrir ou redécouvrir deux artistes montmartrois qui ont marqué le renouveau de l’estampe en couleurs en France à la fin du XIXe siècle : Eugène Delâtre (1864-1938) et Alfredo Müller (1869-1939). Le catalogue de l’exposition présente les deux études que leur consacrent respectivement Nicholas-Henri Zmelty et Hélène Koehl. Il reproduit à la suite l’intégralité des œu..

Joint inversion of seismic and electric data applied to 2D media

Methods based on the seismic P-wave, seismic surface wave, and apparent resistivity are commonly used in the solution of several near-surface problems. However, the solution nonuniqueness and the intrinsic limitations of these methods can cause inconsistency in the final results. Dispersion curves of surface waves, P-wave traveltimes, and apparent-resistivity data were jointly inverted to obtain internally consistent and more reliable final model of P- and S-wave velocities and resistivity. A collection of 1D layered models was obtained by a deterministic joint inversion algorithm based on the laterally constrained inversion scheme. The three data sets were jointly inverted imposing the same structure and Poisson’s ratio was introduced as a physical link between P- and S-wave velocities to better constrain the inversion. No physical link was imposed between the resistivity and the seismic velocities. The inversion algorithm was tested on synthetic data and then applied to a field case, where benchmark borehole data were available. The synthetic and field examples provided results in agreement with the true model and the existing geologic information, respectively

Assessment and aesthetic impact of a long-term vertical discrepancy between the single anterior maxillary implant-supported crown and adjacent teeth: A retrospective cross-sectional study.

OBJECTIVES To assess the vertical discrepancy between implant-supported crowns and adjacent teeth in the maxillary anterior region at least 8 years after implant placement and to evaluate the influence of this discrepancy on the level of aesthetic awareness of patients. MATERIAL AND METHODS The sample consisted of 23 adult individuals evaluated at least 8 years after placement of an implant-supported central or lateral single tooth-fixed partial denture. Patients had their crowns delivered at a mean age of 47.8 years (range: 18.9-65.8). The vertical discrepancy was measured by comparing initial and follow-up periapical radiographs using the implant as a stable structure. The patients' satisfaction with their anterior teeth condition and awareness of the possible vertical problem were evaluated using a questionnaire. The aesthetic outcome and patient awareness were related to the objective measurement of the vertical discrepancy. RESULTS The implant showed a mean infraocclusion of 0.62 mm (range: 0.15-1.63 mm). The vertical discrepancy was not associated with the patient's gender, age at implant placement, and duration between initial and recall radiograph. Patients were generally satisfied with the long-term aesthetic outcome of their smile (mean: 3.9 on a 1-5 scale, 1 unsatisfied, and 5 completely satisfied). Out of 23 patients, 8 noticed the implant infraocclusion and 4 of them found the problem severe enough to be willing to improve the situation. The amount of vertical discrepancy was not associated with the patient's perception of the discrepancy and the pink aesthetic score. CONCLUSION Implant-supported crowns in the anterior region may suffer infraocclusion over the long term. The amount of vertical discrepancy was not dependent on the gender and age of the patient. Patients were generally satisfied with the aesthetic result of the restoration. The amount of vertical discrepancy, at least in the range we have measured, was not perceived by the patients as a complication

Sparse laterally constrained inversion of surface wave dispersion curves via minimum gradient support regularization

We present a 1D laterally constrained inversion of surface wave dispersion curves based on the minimum gradient support regularization, which allows solutions with tunable sharpness in both vertical and horizontal directions. The forward modelling consists of a finite elements approach incorporated in a flexible non-parametric gradient-based inversion scheme, which has already demonstrated good stability and convergence capabilities when tested on other kinds of data. Our deterministic inversion procedure is performed in the shear-wave velocity log-space as we noticed that the associated Jacobian shows a reduced model dependency, and this, in turn, decreases the risks of local non-convexity. We show several synthetics and one field example to demonstrate the effectiveness and the applicability of the proposed approach

Le môle nord-sud de Portus. Seconde campagne de fouilles

Les résultats de la première campagne d’étude du môle nord-sud de Portus, qui avaient permis en 2017 d’en identifier les trois phases de construction (fig. 1), ont été vérifiés et approfondis en 2018 par une intervention ciblée (fig. 2) dans la zone de connexion entre l’extrémité nord du môle de Claude et sa première extension datée de l’époque sévérienne (secteur C). Fig. 1 – Restitution schématique des trois phases de construction du môle nord-sud de Portus : phase claudienne, phase sévérie..

Effect of brine-CO2 fracture flow on velocity and electrical resistivity of naturally fractured tight sandstones

Fracture networks inside geological CO2 storage reservoirs can serve as primary fluid flow conduit, particularly in low-permeability formations. While some experiments focused on the geophysical properties of brine- and CO2-saturated rocks during matrix flow, geophysical monitoring of fracture flow when CO2 displaces brine inside the fracture seems to be overlooked. We have conducted laboratory geophysical monitoring of fluid flow in a naturally fractured tight sandstone during brine and liquid CO2 injection. For the experiment, the low-porosity, low-permeability naturally fractured core sample from the Triassic De Geerdalen Formation was acquired from the Longyearbyen CO2 storage pilot at Svalbard, Norway. Stress-dependence, hysteresis and the influence of fluid-rock interactions on fracture permeability were investigated. The results suggest that in addition to stress level and pore pressure, mobility and fluid type can affect fracture permeability during loading and unloading cycles. Moreover, the fluid-rock interaction may impact volumetric strain and consequently fracture permeability through swelling and dry out during water and CO2 injection, respectively. Acoustic velocity and electrical resistivity were measured continuously in the axial direction and three radial levels. Geophysical monitoring of fracture flow revealed that the axial P-wave velocity and axial electrical resistivity are more sensitive to saturation change than the axial S-wave, radial P-wave, and radial resistivity measurements when CO2 was displacing brine, and the matrix flow was negligible. The marginal decreases of acoustic velocity (maximum 1.6% for axial Vp) compared to 11% increase in axial electrical resistivity suggest that in the case of dominant fracture flow within the fractured tight reservoirs, the use of electrical resistivity methods have a clear advantage compared to seismic methods to monitor CO2 plume. The knowledge learned from such experiments can be useful for monitoring geological CO2 storage where the primary fluid flow conduit is fracture network.acceptedVersio

Predictive value of S100-B and copeptin for outcomes following seizure: the BISTRO International Cohort Study.

OBJECTIVE: To evaluate the performance of S100-B protein and copeptin, in addition to clinical variables, in predicting outcomes of patients attending the emergency department (ED) following a seizure. METHODS: We prospectively included adult patients presented with an acute seizure, in four EDs in France and the United Kingdom. Participants were followed up for 28 days. The primary endpoint was a composite of seizure recurrence, all-cause mortality, hospitalization or rehospitalisation, or return visit in the ED within seven days. RESULTS: Among the 389 participants included in the analysis, 156 (40%) experienced the primary endpoint within seven days and 195 (54%) at 28 days. Mean levels of both S100-B (0.11 μg/l [95% CI 0.07-0.20] vs 0.09 μg/l [0.07-0.14]) and copeptin (23 pmol/l [9-104] vs 17 pmol/l [8-43]) were higher in participants meeting the primary endpoint. However, both biomarkers were poorly predictive of the primary outcome with a respective area under the receiving operator characteristic curve of 0.57 [0.51-0.64] and 0.59 [0.54-0.64]. Multivariable logistic regression analysis identified higher age (odds ratio [OR] 1.3 per decade [1.1-1.5]), provoked seizure (OR 4.93 [2.5-9.8]), complex partial seizure (OR 4.09 [1.8-9.1]) and first seizure (OR 1.83 [1.1-3.0]) as independent predictors of the primary outcome. A second regression analysis including the biomarkers showed no additional predictive benefit (S100-B OR 3.89 [0.80-18.9] copeptin OR 1 [1.00-1.00]). CONCLUSION: The plasma biomarkers S100-B and copeptin did not improve prediction of poor outcome following seizure. Higher age, a first seizure, a provoked seizure and a partial complex seizure are independently associated with adverse outcomes

Induced-seismicity geomechanics for controlled CO2 storage in the North Sea (IGCCS)

The aim of the current study, IGCCS (2017–2020), is to evaluate the feasibility of micro-seismic (MS) monitoring of CO2 injection into representative storage candidates in the North Sea, based on broad and quantitative characterization of relevant subsurface behavior with respect to geology, geomechanics and seismicity. For this purpose, we first group potential CO2 storage sites in the North Sea into three different depths. Then, advanced triaxial rock mechanical tests are performed together with acoustic emission (AE) acquisition under representative loading for CO2 storage sites in the North Sea and for formations of each depth group, covering shale, mudstone and sandstone cores. Our work focuses particularly on quantifying the effects of injected fluid type and temperature on mechanical behavior and associated MS response of subsurface sediments. The experiment results show that each depth group may behave differently in responses to CO2 injection. Particularly, the occurrence of detectable MS events is expected to increase with depth, as the combined effects of rock stiffness and temperature contrast between the host rock and injected CO2 are increasing. In addition, lithology plays an important role in terms of the MS response, i.e. high AE event rate is observed in sandstones, while aseismicity in shale and mudstone. The test results are then scaled up and applied to advanced coupled flow-geomechanics simulations and a synthetic field-scale MS data study to understand micro-seismicity at fracture, reservoir and regional scales. The numerical simulation of scCO2 injection scenario shows quite different stress-strain changes compared to brine injection, resulting mainly from the thermally-induced behavior. Furthermore, the numerical simulation study via so-called Cohesion Zone Modeling (CZM) approach shows strong potential to improve our understanding of the multiphase-flow-driven fracture propagation. Our synthetic MS data study, focused on slow-earthquake scenario, also suggests that sensors with high sensitivity at low frequency might be necessary for better signal detection and characterization during CO2 injection. This manuscript covers the main findings and insights obtained during the whole study of IGCCS, and refers to relevant publications for more details