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Insights from Subsurface Monitoring for Engineering of the Stimulation Pattern in Fractured Reservoirs
No full textInternational audienceStimulation operations enhance the performance of geothermal reservoirs by boosting fluid flow and heat transfer. Predicting stimulation outcomes is challenging due to complexity of reservoir properties and limited observations given by operational conditions. Factors like stress state, natural structures, pressure distribution, and injection patterns play crucial roles in engineering of a stimulation operation. This study provides in-depth observations from a hectometer-scale stimulation experiment conducted at the Bedretto Underground Laboratory for Geosciences and Geoenergies within a densely monitored crystalline rock volume with an overburden of more than 1 km. We found that hydraulic connectivity, pressure compartments, and the characteristics of existing geological structures play pivotal roles in the propagation patterns of seismic events. Notably, the initiation and distribution of seismicity are markedly influenced by the zonal isolation and the structured propagation of pressure front across the reservoir. The research highlights the necessity of adapting stimulation strategies to the unique geomechanical as well as geological characteristics of the reservoir, as evident from the distinct activation patterns observed between the first and second injection cycles. The spatial extent of the stimulated volume can be partially guided by the number of stimulation cycles and injection pressure level, as farther structures are increasingly likely to be activated in the subsequent cycles. The results also indicate that the Kaiser effect is more pronounced in regions closer to the injection borehole. However, this effect can be attenuated due to stress changes caused by stimulation, consistent with a proposition from a recent study. Our findings underscore the critical importance of understanding the interplay between hydraulic pressures and stress states to optimize the stimulation of geothermal reservoirs effectively
CHEX-MATE: Dynamical masses for a sample of 101 Planck Sunyaev-Zeldovich-selected galaxy clusters
No full textInternational audienceThe Cluster HEritage project with XMM-Newton – Mass Assembly and Thermodynamics at the Endpoint of structure formation (CHEX-MATE) is a programme to study a minimally biased sample of 118 galaxy clusters detected by Planck through the Sunyaev–Zeldovich effect. Accurate and precise mass measurements are required to exploit CHEX-MATE as an astrophysical laboratory and a calibration sample for cosmological probes in the era of large surveys. We measured masses based on the galaxy dynamics, which are highly complementary to weak-lensing or X-ray estimates. We analysed the sample with a uniform pipeline that is stable both for poorly sampled or rich clusters –using spectroscopic redshifts from public (NED, SDSS, and DESI) or private archives and dedicated observational programmes. We modelled the halo mass density and the anisotropy profile. Membership is confirmed with a cleaning procedure in phase space. We derived masses from measured velocity dispersions under the assumed model. We measured dynamical masses for 101 CHEX-MATE clusters with at least ten confirmed members within the virial radius r 200c . Estimated redshifts and velocity dispersions agree with literature values when available. Validation with weak-lensing masses shows agreement within 8 ± 16 (stat.) ± 5 (sys.)%, and confirms dynamical masses as an unbiased proxy. Comparison with Planck masses shows them to be biased low by 34 ± 3 (stat.) ± 5 (sys.)%. A follow-up spectroscopic campaign is underway to cover the full CHEX-MATE sample
Chemical transport-based growth of Si and SiGe nanowires
No full textInternational audienceThis study investigates the chemical transport-based growth of Si and Ge nanowires (NWs) using plasma-enhanced chemical vapor deposition. We found that Si NW growth requires a high etching temperature of 400 °C, related to a stronger Si–H bond energy compared to the Ge–H bond energy, allowing Ge NWs to form at 250 °C. The growth process is influenced by various parameters, including etching temperature, radio frequency power, GeH4/SiH4 precursor gas ratios, doping, and inter-electrode distance. Optimal Si NW growth is achieved at a substrate temperature of 250 °C during pre-coating and 400 °C during etching, with an RF power of 100 W. Conversely, Ge NWs can be fabricated at 250 °C, although they tend to be smaller and less dense. The study also highlights the role of the doping of the amorphous film precursors, with n-type doping enhancing growth and crystallization, while p-type doping negatively affects NW formation. Key findings include the significance of maintaining optimal etching time and its effect on NW morphology and uniformity. Overall, the results provide a novel method for efficiently growing Si and Ge NWs, emphasizing the importance of carefully controlling growth conditions
The influence of atmospheric temperature on long-term CPAP-usage in patients with obstructive sleep apnea.
No full textInternational audienceBackground : Although seasonal variations in CPAP-usage are often attributed to changes in temperature, no real- world study has evaluated the influence of temperature on long-term CPAP-usage.Methods : The TempCPAP study is a retrospective real-life cohort study. Adult patients newly treated and undergoing at least 1 month of CPAP were included. Daily 12-PM temperature data from the nearest weather station was assigned to each patient and CPAP-usage was collected using telemonitoring data. The primary objective of the study was to investigate the relationship between temperature and CPAP-usage.Results : 8151 patients (37.2 % women) with a median age of 61 (IQ25-75: 51–71) years, initial AHI of 36 (29–49.6) events/h, treated for a median duration of 1.6 years (0.7–3.0), and with a CPAP-usage of 5.4 (3.0–6.9) h/day were included. The relationship between CPAP-usage and temperature was non-linear. The best model found two breakpoints at 18°C and 29°C. CPAP-usage dropped drastically when the temperature exceeded 29°C, as each 1°C increase was associated with a 3.6-min reduction in CPAP-usage. Compared to temperatures of less than 5°C, temperatures above 30°C resulted in a mean reduction in CPAP-usage of 30.3 (confidence interval (CI95 %): 29.3–31.4) minutes/day, achieving the minimal clinically important difference of 30 min in 46.6 % of patients.Conclusion : In patients undergoing long-term CPAP therapy, temperatures over 29°C at 12-PM were associated with reduced CPAP-usage
Regulation of UCP1 expression by PPARα and pemafibrate in human beige adipocytes
No full textInternational audienceAimsThermogenic adipocytes are able to dissipate energy as heat from lipids and carbohydrates through enhanced uncoupled respiration, due to UCP1 activity. PPAR family of transcription factors plays an important role in adipocyte biology. The purpose of this work was to characterize the role of PPARα and pemafibrate in the control of thermogenic adipocyte formation and function.Materials and methodsWe used human multipotent adipose-derived stem cells and primary cultures of stroma-vascular fraction cells, transfected with siRNA against PPARα, differentiated into white or beige adipocytes, by the treatment of rosiglitazone or pemafibrate. The expression of key marker genes of adipogenesis and thermogenesis was determined using RT-qPCR and Western blotting. An RNAseq analysis was also performed.Key findingsWe show that inhibition of PPARα mRNA increases UCP1 mRNA and protein expression in beige adipocytes induced by rosiglitazone. Knock-down of PPARα also increases stimulated glycerol release. Pemafibrate, described as a selective PPARα modulator, induces adipogenesis and the expression of UCP1 in the absence of PPARα expression. These effects are inhibited by a specific PPARγ antagonist highly suggesting that the pemafibrate effects in adipogenesis and beiging were mediated by PPARγ.SignificanceConversion of white into thermogenic adipocytes is mainly due to the activation of PPARγ. Moreover, we show that PPARα seems to act as a hindrance for PPARγ-dependent beiging. Our data question the role of PPARα in human adipocyte browning and the specificity of pemafibrate in adipocytes
Extraire des données Wikipédia et Wikidata
No full textLicenceThis course offers theoretical and practical support for extracting data from Wikipedia and Wikidata.Ce cours propose des apports théoriques et pratiques pour extraire les données de Wikipédia et Wikidata
When automated fact-checking meets argumentation: unveiling fake news through argumentative evidence
No full textInternational audienceThe need for automated fact-checking has become urgent with the rise of misleading content on social media. Recently, Fake News Classification (FNC) has evolved to incorporate justifications provided by fact-checkers to explain their decisions. In this work, we argue that an argumentative representation of fact-checkers' justifications can improve the precision and explainability of FNC systems. To address this challenging task, we present LIARArg, a novel linguistic resource composed of 2,832 news and their justifications. LIARArg extends the 6-label FNC dataset LIAR-PLUS with argumentation structures, leading to the first FNC dataset annotated with argument components (claim and premise) and fine-grained relations (attack, support, partial support and partial attack). To integrate argumentation in FNC, we propose a novel joint learning method combining, for the first time, Argument Mining and FNC which outperforms state-of-the-art approaches, especially for news with intermediate truthfulness labels. Besides, our experimental setting demonstrates that fine-grained relations allow an extra performance boost. We also show that the argumentative representation of human justifications can be exploited in a Chain-of-Thought manner both in prompts and model output, paving a promising avenue for research in explainable fact-checking. Finally, our fully automated pipeline shows that integrating argumentation into FNC is not only feasible but also effective
Le caractère obligatoirement contradictoire de l'expertise consumériste
No full textInternational audience(Crim. 23 avr. 2024, no 23-84.390, inédit, Dr. pénal 2024, comm. 130, obs. J.-H. Robert
Exploration du concept de « tiers-lieu culturel"
No full textInternational audienceCette contribution a pour objectif d’explorer la catégorie « tiers-lieu culturel » à travers sa généalogie pour en comprendre les conditions d’émergence, de développement et finalement son sens. Dans une première partie, nous revenons sur la filiation conceptuelle des tiers-lieux culturels en référence avec la notion plus large de tiers-lieux. Dans un deuxième temps, nous analyserons les liens de filiation entre les tiers-lieux culturels et ce que nous appelons ici les lieux du renouvellement de la relation à l’art et à la culture (squats, friches culturelles, lieux intermédiaires, nouveaux territoires de l’art, etc.). Il s’agit de faciliter la compréhension de l’espace sémantique et social dans lequel circulent des dénominations nombreuses et recouvrant des histoires et des réalités différentes, en faisant appel à un ensemble de ressources théoriques et professionnelles produites. Enfin, nous terminerons en réfléchissant aux conditions de comparaison internationale de tiers-lieux culturels, sachant qu’il n’existe pas de terme générique unique qui ferait consensus