Simulations of driven overdamped frictionless hard spheres

We introduce an event-driven simulation scheme for overdamped dynamics of frictionless hard spheres subjected to external forces, neglecting hydrodynamic interactions. Our event-driven approach is based on an exact equation of motion which relates the driving force to the resulting velocities through the geometric information characterizing the underlying network of contacts between the hard spheres. Our method allows for a robust extraction of the instantaneous coordination of the particles as well as contact force statistics and dynamics, under any chosen driving force, in addition to shear flow and compression. It can also be used for generating high-precision jammed packings under shear, compression, or both. We present a number of additional applications of our method.Comment: 12 pages, 9 figure

Extracorporeal Membrane Oxygenation for Severe Acute Respiratory Distress Syndrome associated with COVID-19: An Emulated Target Trial Analysis.

RATIONALE: Whether COVID patients may benefit from extracorporeal membrane oxygenation (ECMO) compared with conventional invasive mechanical ventilation (IMV) remains unknown. OBJECTIVES: To estimate the effect of ECMO on 90-Day mortality vs IMV only Methods: Among 4,244 critically ill adult patients with COVID-19 included in a multicenter cohort study, we emulated a target trial comparing the treatment strategies of initiating ECMO vs. no ECMO within 7 days of IMV in patients with severe acute respiratory distress syndrome (PaO2/FiO2 <80 or PaCO2 ≥60 mmHg). We controlled for confounding using a multivariable Cox model based on predefined variables. MAIN RESULTS: 1,235 patients met the full eligibility criteria for the emulated trial, among whom 164 patients initiated ECMO. The ECMO strategy had a higher survival probability at Day-7 from the onset of eligibility criteria (87% vs 83%, risk difference: 4%, 95% CI 0;9%) which decreased during follow-up (survival at Day-90: 63% vs 65%, risk difference: -2%, 95% CI -10;5%). However, ECMO was associated with higher survival when performed in high-volume ECMO centers or in regions where a specific ECMO network organization was set up to handle high demand, and when initiated within the first 4 days of MV and in profoundly hypoxemic patients. CONCLUSIONS: In an emulated trial based on a nationwide COVID-19 cohort, we found differential survival over time of an ECMO compared with a no-ECMO strategy. However, ECMO was consistently associated with better outcomes when performed in high-volume centers and in regions with ECMO capacities specifically organized to handle high demand. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Le Dossier Médical Personnel en 2010 (quelles attentes et quelles perspectives en médecine générale?)

Créé par la loi du 13 août 2004, le Dossier Médical Personnel (DMP) doit proposer à chaque assuré social un dossier médical accessible via internet par les professionnels de santé et le patient.Après de multiples reports et débats tant techniques que juridiques et éthiques, sa mise en place est annoncée pour la fin de l'année 2010.Malgré ce temps passé, le concept du DMP apparaît encore flou pour les médecins qui en seront pourtant les principaux utilisateurs.Notre enquête met en évidence les attentes et les craintes des médecins généralistes face à ce nouvel outil et vérifie que les prérequis techniques nécessaires à son utilisation sont réunis.Puis dans une discussion, nous tentons de déterminer les bénéfices et les limites du DMP pour la médecine générale ainsi que ses conséquences sur l'exercice professionnel.Le DMP apparaît comme un outil potentiellement très utile dans la pratique médicale tant au niveau de la prise en charge du patient et de la coordination des soins qu'en terme de santé publique.Cependant, des questions se posent, notamment au sujet de la sécurité et du respect du secret médical.La mise en place effective du DMP est susceptible de modifier l'exercice de la médecine générale : il apporte de nouvelles obligations d'alimentation et de coordination, qui seront sans doute chronophages, particulièrement au début.Il participe à l'évolution de la médecine devenue collective avec un médecin traitant désormais coordinateur des soins et un patient devenu acteur de sa santéMONTPELLIER-BU Médecine UPM (341722108) / SudocMONTPELLIER-BU Médecine (341722104) / SudocSudocFranceF

In situ measurement with diffusive gradients in thin films: effect of biofouling in freshwater

Concerning in situ passive sampler deployment, several technical priorities must be considered. In particular, deployment time must be sufficiently long not only to allow a significant quantity to be accumulated to facilitate analysis but also to ensure that the signal is above the quantification limit and out of the blank influence. Moreover, regarding the diffusive gradient in thin films (DGT) technique, deployment time must also be sufficiently long (at least 5 days) to avoid the interactions of the solutes with the material diffusion layer of the DGT and for the steady state to be reached in the gel. However, biofouling occurs in situ and modifies the surface of the samplers. In this article, we propose a kinetic model which highlights the biofouling effect. This model was able to describe the mitigation of the flux towards the DGT resin observed on Cd, Co, Mn, Ni and Zn during a 22-day deployment in the Seine River. Over a period of 22 days, biofouling had a significant impact on the DGT concentrations measured, which were decreased twofold to threefold when compared to concentrations measured in unaffected DGTs

In situ measurement with diffusive gradients in thin films: effect of biofouling in freshwater

Concerning in situ passive sampler deployment, several technical priorities must be considered. In particular, deployment time must be sufficiently long not only to allow a significant quantity to be accumulated to facilitate analysis but also to ensure that the signal is above the quantification limit and out of the blank influence. Moreover, regarding the diffusive gradient in thin films (DGT) technique, deployment time must also be sufficiently long (at least 5 days) to avoid the interactions of the solutes with the material diffusion layer of the DGT and for the steady state to be reached in the gel. However, biofouling occurs in situ and modifies the surface of the samplers. In this article, we propose a kinetic model which highlights the biofouling effect. This model was able to describe the mitigation of the flux towards the DGT resin observed on Cd, Co, Mn, Ni and Zn during a 22-day deployment in the Seine River. Over a period of 22 days, biofouling had a significant impact on the DGT concentrations measured, which were decreased twofold to threefold when compared to concentrations measured in unaffected DGTs

City map of ancient Epomanduodurum (Mandeure - Mathay, Franche-Comté, eastern France) : contribution of geophysical prospecting techniques.

International audienceThis study presents the main results of the geophysical survey of ancient Epomanduodurum, at Mandeure-Mathay, Eastern France. In northeastern Gaul, Epomanduodurum is a site of a major scientific interest for the understanding of past settlements and territorial formation at the end of the Iron Age and during the Roman period. The site, including a Roman urban centre and two suburbs containing workshops, occupies more than 500 ha inside and beyond a meander of the River Doubs. From the beginning of survey in 2001, several methods (fast electrical imaging automatic resistivity profiling system, ground penetrating radar, magnetic and electromagnetic mapping) have been performed on a large scale in order to precisely identify the vast extent and structure of the Roman town. The interpretation of the geophysical data was carried out using a combination of different data sources, including ancient maps and excavations recently conducted on restricted areas. The overall organization of an artisan quarter of 8 ha was revealed along a main Roman road leading to the left bank of the River Doubs. On the other bank, a river fortification and a vast monumental religious complex were recognized in the southern part of the Roman town. The geophysical imaging shows that the sacred area includes several temples or groups of temples radiating from the theatre. Other new buried structures probably corresponding to annexes, chapels and altars were also detected within this sacred area of 10 ha bound on three sides by a wall enclosure with monumental passages. In a surveyed area of 70 ha, geophysical prospecting techniques provided a clear overall image of the Roman urbanism revealed through a rectangular road network and street system delimiting insulae of variable sizes. The detection along the River Doubs of buildings similar to storehouses attests to fluvial transport and also suggests the likely existence of a port. More generally, the combination on a large scale of geophysical prospecting, aerial photographs and excavations allowed a new plan of the urban structure of the ancient town of Epomanduodurum to be produced for an area of over 300 ha

Does 3D frequency-domain FWI of full-azimuth/long-offset OBN data feasible? The Gorgon case study

Frequency-domain Full Waveform Inversion (FWI) is potentially amenable to efficient processing of full-azimuth long-offset stationary-recording seabed acquisition carried out with sparse layout of ocean bottom nodes (OBNs) and broadband sources because the inversion can be performed with a few discrete frequencies. However, computing efficiently the solution of the forward (boundary-value) problem in the frequency domain with linear algebra solvers remains a challenge for large computational domains involving tens to hundreds of millions of parameters. We illustrate the feasibility of 3D frequency-domain FWI with the 2015/16 Gorgon OBN case study in the NorthWestern shelf, Australia. We solve the forward problem with the massively-parallel multifrontal direct solver MUMPS, which includes four key features to reach high computational efficiency: An efficient parallelism combining message-passing interface and multithreading, block low-rank compression, mixed precision arithmetic and efficient processing of sparse sources. The Gorgon subdataset involves 650 OBNs that are processed as reciprocal sources and 400,000 sources. Mono-parameter FWI for vertical wavespeed is performed in the visco-acoustic VTI approximation with a classical frequency continuation approach proceeding from a starting frequency of 1.7 Hz to a final frequency of 13 Hz. The target covers an area ranging from 260 km2 (frequency > 8.5 Hz) to 705 km2 (frequency < 8.5 Hz) for a maximum depth of 8 km. Compared to the starting model, FWI dramatically improves the reconstruction of the bounding faults of the Gorgon horst at reservoir depths as well as several intra-horst faults and several horizons of the Mungaroo formation down to a depth of 7 km

Aspergillose pulmonaire invasive chez les patients sous ventilation mécanique: incidence et devenir (APICOVID)

International audienceBackground - Recent studies identified coronavirus disease 2019 (COVID-19) as a risk factor for invasive pulmonary aspergillosis (IPA) but produced conflicting data on IPA incidence and impact on patient outcomes. We aimed to determine the incidence and outcomes of COVID-19-associated pulmonary aspergillosis (CAPA) in mechanically ventilated patients. Methods - We performed a multicenter retrospective observational cohort study in consecutive adults admitted to 15 French intensive care units (ICUs) in 2020 for COVID-19 requiring mechanical ventilation. CAPA was diagnosed and graded according to 2020 ECMM/ISHAM consensus criteria. The primary objective was to determine the incidence of proven/probable CAPA, and the secondary objectives were to identify risk factors for proven/probable CAPA and to assess associations between proven/probable CAPA and patient outcomes. Results - The 708 included patients (522 [73.7%] men) had a mean age of 65.2 ± 10.8 years, a median mechanical ventilation duration of 15.0 [8.0-27.0] days, and a day-90 mortality rate of 28.5%. Underlying immunosuppression was present in 113 (16.0%) patients. Corticosteroids were used in 348 (63.1%) patients. Criteria for probable CAPA were met by 18 (2.5%) patients; no patient had histologically proven CAPA. Older age was the only factor significantly associated with probable CAPA (hazard ratio [HR], 1.04; 95% CI 1.00-1.09; P = 0.04). Probable CAPA was associated with significantly higher day-90 mortality (HR, 2.07; 95% CI 1.32-3.25; P = 0.001) but not with longer mechanical ventilation or ICU length of stay. Conclusion - Probable CAPA is a rare but serious complication of severe COVID-19 requiring mechanical ventilation and is associated with higher day-90 mortality