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Euclid: Early Release Observations -- Deep anatomy of nearby galaxies
No full textInternational audienceEuclid is poised to make significant advances in the study of nearby galaxies in the local Universe. Here we present a first look at 6 galaxies observed for the Nearby Galaxy Showcase as part of the Euclid Early Release Observations acquired between August and November, 2023. These targets, 3 dwarf galaxies (HolmbergII, IC10, NGC6822) and 3 spirals (IC342, NGC2403, NGC6744), range in distance from about 0.5 Mpc to 8.8 Mpc. Our assessment of the surface brightness depths in the stacked Euclid images confirms previous estimates in 100 arcsec^2 regions of 1sigma=30.5 mag/arcsec^2 for VIS, but slightly deeper than previous estimates for NISP with 1sigma=29.2-29.4 mag/arcsec^2. By combining Euclid HE, YE, and IE into RGB images, we illustrate the large field-of-view covered by a single Reference Observing Sequence, together with exquisite detail on parsec scales in these nearby galaxies. Radial surface brightness and color profiles demonstrate galaxy colors in agreement with stellar population synthesis models. Standard stellar photometry selection techniques find approximately 1.3 million stars across the 6 galaxy fields. Euclid's resolved stellar photometry allows us to constrain the star-formation histories of these galaxies, by disentangling the distributions of young stars, as well as asymptotic giant branch and red giant branch stellar populations. We finally examine 2 galaxies individually for surrounding satellite systems. Our analysis of the ensemble of dwarf satellites around NGC6744 reveals a new galaxy, EDwC1, a nucleated dwarf spheroidal at the end of a spiral arm. Our new census of the globular clusters around NGC2403 yields 9 new star-cluster candidates, 8 of which with colors indicative of evolved stellar populations. In summary, our investigation of the 6 Showcase galaxies demonstrates that Euclid is a powerful probe of the anatomy of nearby galaxies [abridged]
Les « doubles suivis » comme situations frontières Pratiques professionnelles et différenciations sociales des jeunes suivis par l'ASE et la PJJ
No full textCe rapport de recherche rend compte des résultats d’une enquête conduite deux ans durant sur les jeunes doublement suivis, c’est-à-dire pris en charge par l’Aide sociale à l’enfance (ASE), au titre de l’enfance en danger, et par la Protection judiciaire de la jeunesse (PJJ), au titre de l’enfance délinquante. Elle fait suite à l’appel à projets « Trajectoires » lancé par la Direction de la protection judiciaire de la jeunesse en 2021 sur la question de « l’analyse des parcours de jeunes faisant l’objet d’un double suivi ».Le cahier des charges de cet appel portait sur la compréhension de ces situations et de ce qui les engendre, et sur les effets sur les parcours des jeunes de ces prises en charge
Frequency Comb Generation Induced by Internal Mode Coupling in Silicon Nitride Drum Resonators
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Désinformation et observance thérapeutique en oncologie : deux études expérimentales par vignette en population générale
No full textInternational audienceContexte : L’impact de la désinformation en oncologie reste peu étudié (Swire-Thompson & Johnson, 2024). Des études corrélationnelles en population générale ont montré un lien entre croyances conspirationniste (CCs) et intention de recourir à des médecines alternatives (MA) en replacement des traitements conventionnels (Fournier & Varet, 2024). La présente recherche visait à tester la causalité de ces relations et identifier des leviers interventionnels.Méthodes : Deux études expérimentales en ligne (N = 258 et 462) préenregistrées (https://doi.org/10.17605/OSF.IO/2EDT9) manipulaient l’exposition à un contenu de désinformation relayant des CCs sur les traitements oncologiques et évaluaient sa crédibilité. Les participants sans antécédents de cancer se projetaient dans la position d'un patient recevant un diagnostic de cancer avec recommandation de chimiothérapie.Résultats : Etude 1 : l'exposition à un contenu pro-CCs (vs. anti-CCs) augmentait les intentions de recours à des MA en remplacement de la chimiothérapie, via un effet sur les CCs, uniquement chez les participants jugeant le contenu très crédible (effet indirect à +1 E.T. : d = 1.25, IC95% [0.95, 1.58]). Etude 2 : lorsque l’exposition à l’article pro-CCs était précédée d’une induction (vs. non-induction) à la vigilance et l’exactitude, l’intention de recourir aux MA en remplacement était réduite (effets indirects agrégés via la crédibilité et les CCs : d = -0.30, IC95% [-0.49, 0.11]).Discussion : Ces résultats corroborent l'existence d’effets délétères de la désinformation sur les comportements de santé en oncologie. Les implications et limites pour les réduire en population générale (e.g., dépistage) et clinique (e.g., adhésion thérapeutique) seront discutés
Enhancing photovoltaic panel efficiency through Water-Cooling: A parametric comparative evaluation of energetic, economic, and environmental benefits
No full textInternational audienceThe pressing need for more effective solar technology is highlighted by the global transition away from fossil fuels and toward renewable energy sources. Despite the enormous potential of photovoltaic (PV) panels, efficiency losses in high-temperature conditions limit their performance. The purpose of this study is to theoretically evaluate the energy, financial, and environmental advantages of different water-cooling techniques intended to improve the sustainability and operating efficiency of PV panels. In contrast to traditional research, this work quantifies increases in energy output, cost savings, and CO2 emission reductions across various cooling configurations by a thorough parametric analysis inside a single theoretical framework. To simulate how various water-cooling methods affect PV panel performance, a mathematical parametric model was created. Energy production, cost savings, and carbon footprint reduction were among the key performance metrics computed and compared for PV applications in relation to the consumption ratio R, which is defined as the ratio of the actual building load to the maximum PV power output, or the amount of energy consumed by the house from the PV panels. With an annual energy gain of 1354.10R kWh per panel, cost savings of 582.26R USD, and CO2 emission reductions of 785.37R kg, jet water impingement cooling (JWPV) outperformed the other technologies under evaluation. However, with energy gains of 1061.53R kWh, savings of 456.46R USD, and CO2 reductions of 615.68R kg, evaporative cooling (EPV) produced the least amount of improvement. These results highlight how important efficient cooling is to improving PV panel performance and developing sustainable solar energy solutions
Joint Sub-6 GHz and mm-Wave V2I MIMO Radio Channel Characterization
No full textInternational audienceThe development of 5G and 6G networks has driven to the development of two key technologies: massive Multiple-Input Multiple-Output (mMIMO) and access to millimeter wave (mm-Wave) frequencies [1], and the concept of distributed cell-free massive MIMO (CF-mMIMO), primarily targeting sub-6GHz frequencies [2], [3]. In this context, the demand for very high-speed systems is growing rapidly, especially for scenarios with a high density of users. In particular, the transmission of navigation, safety and multimedia entertainment data in vehicles is a major challenge, requiring a communication scheme with very high throughput, low latency and very high coverage quality. To meet these objectives, CF-mMIMO technology is a promising candidate: distributed antennas provide seamless coverage and their synchronization reduces latency, while guaranteeing high throughput. The spectrum for these systems is generally in the sub-6 GHz range (FR1), where moderate attenuation ensures a favorable link budget. In order to increase capacity, wider frequency bands are also being investigated in other parts of the radio spectrum, for example in the millimetre-wave range (FR2) where bandwidths of up to 100 MHz are available in the 26–28 GHz and 40 GHz bands.The coexistence of these technologies would require a fine exploitation of radio channel characteristics considering vehicle and user mobility for Vehicule-to- Infrastructure (V2I) and Vehicle-to-Vehicle (V2V) applications. At mm-Wave frequencies, most current mm- Wave V2X measurements are conducted in static environments rather than dynamic ones, and primarily focus on propagation losses [4]. The limited number of mm- Wave V2V channel measurements makes it difficult to draw statistically significant conclusions about real-world mm-Wave V2V channels. In [5], [6] dynamic V2V SISO channel measurements were performed to investigate the large-scale parameters and stationarity. Channel sounder and first measurements for CF-mMIMO have been presented in [7], [8]. More recently investigations on large-scale parameters have been presented in [9]. V2V measurements at 3 GHz and 30 GHz in urban scenarios have been described in [10].In this article, we present a dual-band channel measurement campaign for the V2I scenario, in which the sub-6GHz and mm-Wave frequency ranges are jointly sounded. More specifically, the multipath channel is evaluated simultaneously at 5.93 GHz and 26.5 GHz using two complementary real-time MIMO sounders. The experimental setup is provided in Section II. The measurement campaign is described in Section III. Data processing is detailed in Section IV, and the results in terms of Power Delay Profile (PDP), Doppler Spectral Density (DSD) and path loss are illustrated in Section V
Impact of the incorporation of clove and sesame flour in the formulation of dry chicken sausages on their quality during the fermentation stage
No full textInternational audienceThis study aimed to investigate the effect of sesame flour and clove on the physico-chemical, colorimetric and structural quality of sausages during their fermentation stage. The results indicated that clove could be used as an antioxidant source in sausages produced with sesame flour. The principal component analysis (PCA) applied to the physicochemical and colorimetric data set allowed to clearly differentiate sausage samples according to the fermentation stage and, to a lesser extent, their recipes. This trend was confirmed by factorial discriminant analysis (FDA), since 97.22% of correct classification was noted. The PCA applied on the mid infrared (MIR) spectra allowed to differentiate sausage according to their formulations; this trend was confirmed by the FDA since 100% of correct classification of the samples were obtained.The partial least squares regression (PLSR) allowed a perfect prediction of the physicochemical parameters from the MIR spectra, since R2 higher than 0.85 were found for the calibration and validation model, respectively
19 mW/μm² and 24.5 % PAE at 94 GHz for 0.30-μm Transferred InP/GaAsSb DHBT on Si-HR
No full textInternational audienceInP HBT technology is a suitable candidate for the future 6G networks that require very high bandwidth. It has already demonstrated high-frequency operation with fmax exceeding 1 THz [1]. However, this performance comes at the cost of aggressive scaling which increases thermal resistance (Rth) due to device narrowing and leads to self-heating limiting overall performance. Transferring InP DHBT to a high-thermal-conductivity substrate has shown a drastic reduction of Rth by 65 % on Si-HR [2] and 75 % on SiC [3] thanks to their superior heat dissipation properties however its effect on output power remains unexplored. We present continuous wave (CW) large-signal load-pull measurements at 94 GHz of a transferred InP/GaAsSb DHBT transistor fabricated on a high-resistivity silicon substrate (HR-Si). The characterized device features an emitter area of 0.29 × 4.9 μm² and was biased for both maximum output power and maximum power-added-efficiency (P.A.E). A peak output power of 14.25 dBm (18,84 mW/μm²) was achieved. This result demonstrates the impact of thermal dissipation in reducing self-heating and enabling higher output power
13 mW/μm² and 24 % PAE at 94 GHz for 0.44-μm Transferred InP/GaAsSb DHBT on Si
No full textInternational audienceWe present large-signal load-pull measurements of a transferred InP/GaAsSb double heterojunction bipolar transistor fabricated on a high-resistivity silicon substrate. The tested devices feature an emitter area of 0.44 × 3.9 µm². When biased for highest power, an output power of 13.42 dBm was achieved corresponding to a power density of 12.92 mW/µm² (5.68 W/mm). A peak value of 23.7 % was obtained along with a power gain of 5.35 dB when the load impedance was optimized for maximum power-added efficiency (P.A.E). These results highlight the benefits of thermal dissipation improvement in overcoming self-heating effects to achieve high output power.</div