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La place et l'influence espagnoles dans le cadre décisionnel de l'Union européenne
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Competing effects of charge-carrier and impurity scattering limiting phonon heat conduction in heavily-doped silicon
No full textWith respect to undoped semiconductors, thermal transport by phonons is limited by two additional mechanisms when doping increases: charge-carrier and impurity scattering. Previous works provided contradicting conclusions on the dominant doping-induced scattering mechanism in silicon. In this work, we clarify the competing roles of impurity and charge-carrier scatterings of phonons in the reduction of the lattice thermal conductivity in n-and p-doped silicon, by comparing experimental results obtained with the 3ω method and predictive DFT-based calculations for a large set of doping concentrations and a wide temperature range. The analysis allows delimiting the doping and temperature ranges where (i) extrinsic scattering surpasses intrinsic (phonon-phonon and phonon-isotope) one and (ii) one of the two doping-induced mechanisms plays the dominant role. We observe that the experimental setup impacts both the thermal conductivity value and the critical doping concentration at which the thermal conductivity is reduced by half
Euclid Quick Data Release (Q1): Euclid spectroscopy of QSOs. 1. Identification and redshift determination of 3500 bright QSOs
No full textInternational audienceThe slitless spectroscopy mode of the NISP onboard Euclid has enabled efficient spectroscopy of objects within a large FoV. We present a large and homogeneous sample of bright quasars identified from the Euclid Quick Data Release (Q1) by combining high-purity candidate selections from Gaia and WISE with the NISP spectra. Through visual inspection of the Euclid spectra of these quasar candidates, we identify approximately 3500 quasars with reliable redshifts at . We generate the first Euclid composite spectrum of quasars covering rest-frame NUV to NIR wavelengths without telluric lines, which will be pivotal to NIR quasar spectral analysis. We obtain an empirical spectroscopic depth of and at the sensitivity of the Wide Field Survey, beyond which the number of securely identified quasars declines sharply. We analyse VIS morphologies using Sersic and CAS metrics, and a deep-learning PSF fraction to track nuclear dominance. At low redshift (), obvious host structures are common and a single Sersic model fits about half of the sources; at intermediate redshift (), the nuclear component dominates, with 90% of the Sersic fits saturating at the upper index limit. In this intermediate redshift regime, is available, and we use it as a more reliable compactness measure than the single-Sersic and CAS parameters to quantify nuclear versus host emission. We also explore the novel Euclid NIR colour space and discuss the role of these quasars in refining AGN selection techniques for future Euclid data releases. Our results highlight the potential of Euclid spectroscopy to advance quasar surveys and enable the construction of more complete AGN catalogues. The spectroscopic bright quasar catalogue of this work, and the composite quasar spectrum, will be available at https://cdsarc.cds.unistra.fr/. (abridged
Geometric Approach to Plane Trigonometry Using Classical Constructions
No full textInternational audienceThis document offers a geometric perspective on plane trigonometry, based on classical constructions using squares, circles, and triangles. Using only fundamental mathematical concepts, we are able to determine the exact values of the sine and cosine trigonometric functions for specific angles such as 15°, 30°, 45°, and 75° without a calculator. These results are obtained using construction techniques inspired in particular by the work of Abu al-Wafa. We then establish the laws of cosine using elementary geometric constructions and prove Mollweide's formulas based on the characteristics of isosceles triangles and the laws of sine. This approach highlights the link between Euclidean geometry and trigonometry, while proving to be a valuable educational tool for teaching at secondary and university level
Cartographier l'écosystème des e-pétitions via les médias sociaux :mobilisation dans l'UE autour d'enjeux et idéologies
No full textInternational audienceWe study petition-related mobilization on Social Media across issues and ideologies. Using calls to sign petitions on X in the seven most spoken EU languages, we build the first multi-platform, multi-language map of the e-petitioning ecosystem. To ensure cross-language and cross-ideology comparability, we infer call for signatures’ issues using ManifestoBERTa and users' ideological orientation via Ideology Scaling methods calibrated using expert survey data. We classify active individuals into an ontology of mobilization types. Results show that e-petition activism is issue-specific and short-lived, with only a small portion of individuals engaging in sustained mobilization. We characterize differences in e-activism across the Left-Right spectrum, with Right-leaning users being most active on issues like political corruption and traditional morality, while environmental protection sees low engagement levels compared to its reach.Nous étudions la mobilisation liée aux pétitions sur les réseaux sociaux, à travers différents enjeux et idéologies. En nous appuyant sur des appels à la signature de pétitions diffusés sur X, dans les sept langues les plus parlées de l’Union européenne, nous construisons la première cartographie multi-plateforme et multilingue de l’écosystème de l’e-pétitionnement. Afin de garantir la comparabilité interlinguistique et inter-idéologique, nous inférons les thématiques des appels à signatures à l’aide de ManifestoBERTa et estimons l’orientation idéologique des utilisateurs au moyen de méthodes de Ideology Scaling calibrées à partir de données d’enquêtes d’experts. Nous classons les individus actifs au sein d’une ontologie des types de mobilisation. Les résultats montrent que l’activisme par e-pétition est fortement dépendant des enjeux et de courte durée, seule une minorité d’individus s’engageant dans une mobilisation soutenue. Nous mettons en évidence des différences marquées dans l’e-activisme le long du clivage gauche-droite : les utilisateurs orientés à droite sont les plus actifs sur des enjeux tels que la corruption politique et la morale traditionnelle, tandis que la protection de l’environnement suscite des niveaux d’engagement relativement faibles au regard de sa portée
: The Unspoken at Work in Selected Literary Testimonies from Fukushima
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Graph theory-based exploration of structure and dynamics of surface organometallic catalysis
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Generative Models of 21cm EoR Lightcones with 3D Scattering Transforms
No full textInternational audienceThe 21cm signal from the Epoch of Reionization (EoR) is observed as a three-dimensional data set known as a lightcone, consisting of a redshift (frequency) axis and two spatial sky plane axes. When observed by radio interferometers, this EoR signal is strongly obscured by foregrounds that are several orders of magnitude stronger. Due to its inherently non-Gaussian nature, the EoR signal requires robust statistical tools to accurately separate it from these foreground contaminants, but current foreground separation techniques focus primarily on recovering the EoR power spectrum, often neglecting valuable non-Gaussian information. Recent developments in astrophysics, particularly in the context of the Galactic interstellar medium, have demonstrated the efficacy of scattering transforms - novel summary statistics for highly non-Gaussian processes - for component separation tasks. Motivated by these advances, we extend the scattering transform formalism from two-dimensional data sets to three-dimensional EoR lightcones. To this end, we introduce a 3D wavelet set from the tensor product of 2D isotropic wavelets in the sky plane domain and 1D wavelets in the redshift domain. As generative models form the basis of component separation, our focus here is on building and validating generative models that can be used for component separation in future projects. To achieve this, we construct maximum entropy generative models to synthesise EoR lightcones, and statistically validate the generative model by quantitatively comparing the synthesised EoR lightcones with the single target lightcone used to construct them, using independent statistics such as the power spectrum and Minkowski Functionals. The synthesised lightcones agree well with the target lightcone both statistically and visually, opening up the possibility of developing for component separation methods using 3D scattering transforms
Fraseoculturoloxía e fraseotradutoloxía contrastiva:estereotipos e representacións da cabeza en chinés e francés1
No full textInternational audienceThis study explores the contrastive phraseoculture (Chen, 2022) of idiomatic expressions(IEs) in French and Chinese, with a focus on the body part “head”; and its metaphorical, cultural, andcognitive representations. Drawing on phraseoculturology (Chen, 2022) and phraseotraductologyou phraseotranslation (Sułkowska, 2016), the research highlights how fixed expressions—such asFrench idiomatic expressions and Chinese chéngyŭ—encode culturally specific worldviews andreflect divergent philosophical and medical traditions. While Western languages often associatethe head with intellect, logic, and individuality, Chinese tradition, influenced by classical medicineand Confucian philosophy, attributes these functions to the heart (心, xīn), conceptualized as theunified seat of thought and emotion. Based on a bilingual corpus of 118 high-frequency IEs (68 inChinese, 50 in French), the analysis reveals both metaphorical convergences and divergences.Common physiological experiences lead to shared expressions (e.g.; from head to toe, 从头到脚), while deeper cultural models generate asymmetries, such as the metaphorical use of theheart in Chinese where French uses the head. Many Chinese expressions still reflect traditionalconceptualizations rooted in heart-centered cognition, despite anatomical reevaluations since theMing and Qing dynasties. The study identifies cases of direct equivalence, partial equivalence,and cultural mismatch, emphasizing that many IEs are untranslatable word-for-word due to theirmetaphorical and culture-specific nature. This semantic and conceptual asymmetry illustrates thechallenges of phraseotraductology and underscores the necessity of a phraseocultural approachin translation studies. Ultimately, the findings contribute to a better understanding of interculturalphraseological transfer and reinforce the value of contrastive idiomatic analysis in both linguisticresearc h and p edagogi c al p rac t i c e.O est u do exp lora a f raseoc u lt u roloxía c ont rast i v a ( Ch en, 2022) das exp resi ó ns i di om á t i c as(EI) en francés e chinés cun enfoque na parte do corpo «cabeza» e nas súas representaciónsmetafóricas, culturais e cognitivas. Baseándose na fraseoculturoloxía (Chen, 2022) efraseotradutoloxía ou fraseotradución (Sułkowska, 2016), a investigación resalta como as expresiónsfixas, como as expresións idiomáticas fixas do francés ou os chéngyŭ chineses, codifican visiónsdo mundo culturalmente específicas e reflicten tradicións filosóficas e médicas diverxentes. Mentresque as linguas occidentais asocian normalmente a cabeza co intelecto, a lóxica e a individualidade, atradición chinesa, influenciada pola medicina clásica e a filosofía confuciana, atribúe estas funciónsao corazón (心, xīn), conceptualizado como o asento unificado do pensamento e da emoción.Baseado nun corpus bilingüe de 118 unidades fraseolóxicas de alta frecuencia (68 en chinés e 50en francés), a análise revela converxencias e diverxencias metafóricas. As experiencias fisiolóxicascomúns dan lugar a expresións compartidas (p. ex., `dos pés á cabeza`, / 从头到脚) , m ent resque os modelos culturais máis profundos xeran asimetrías, como o uso metafórico do corazón en chinéscando o francés usa a cabeza. Moitas expresións chinesas aínda reflicten conceptualizaciónstradicionais baseadas nunha cognición centrada no corazón, a pesar das reavaliacións anatómicasdende as dinastías Ming e Qing. O estudo identifica casos de equivalencia directa, equivalenciap arc i al e desac ordo c u lt u ral, sali ent ando q u e m oi t as exp resi ó ns i di om á t i c as non se p oden t radu c i rliteralmente debido á súa natureza metafórica e culturalmente específica. Esta asimetría semánticae c onc ep t u al i lu st ra os desaf íos da f raseot radu t oloxía e su b li ñ a a nec esi dade du nh a ap roxi m ac i ó nf raseoc u lt u ral nos est u dos da t radu c i ó n. E n ú lt i m a i nst anc i a, os resu lt ados c ont ri b ú en a u nh a m ellorcomprensión da transferencia fraseolóxica intercultural e reforzan o valor da análise contrastiva deexpresións idiomáticas tanto na investigación lingüística como na práctica pedagóxic
