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Anatomy of torques from orbital Rashba textures: the case of Co/Al interfaces
No full textIn the context of orbitronics, the rising of the orbital angular momentum generated at light metal interfaces from orbital textures via orbital Rashba-Edelstein effects nowadays represent extraordinary alternatives to the usual heavy-metal spin-based materials. In the light of very recent experimental results [\textcolor{blue}{S. Krishnia \textit{et al.}, Nanoletters 2023, 23, 6785}], starting from state-of-the-art density functional theory simulations, we provide theoretical insights into the emergence of very strong orbital torques at the Co/Al interface location a strong orbital Rashba texture. By using linear response theory, we calculate the exerted orbital torque amplitudes, mainly of field-like intraband character, acting onto the ultrathin Co. Moreover, we show that an insertion of a single atomic plane of Pt between Co and Al is enough to suppress the effect which questions about the anatomy of the torque action clearly behaving differently than in the standard way. This work opens new routes to the engineering of spintronic devices
A promiscuous Bcd amino acid dehydrogenase promotes biofilm development in Bacillus subtilis
No full textInternational audienceGlutamate dehydrogenase (GDH) resides at the crossroads of nitrogen and carbon metabolism, catalyzing the reversible conversion of L-glutamate to α-ketoglutarate and ammonium. GDH paralogs are ubiquitous across most species, presumably enabling functional specialization and genetic compensation in response to diverse conditions. Staphylococcus aureus harbors a single housekeeping GDH (GudB), whereas Bacillus subtilis encodes both a major and a minor GDH, GudB and RocG, respectively. In an unsuccessful attempt to identify an alternative GDH in S. aureus, we serendipitously discovered previously unrecognized GDH activity in two metabolic enzymes of B. subtilis. The hexameric Val/Leu/Ile dehydrogenase Bcd (formerly YqiT) catabolizes branched-chain amino acids and to a lesser extent glutamate using NAD+ as a cofactor. Removal of gudB and rocG unmasks the dual NAD(P)+-dependent GDH activity of RocA, which otherwise functions as a 3-hydroxy-1-pyrroline-5-carboxylate dehydrogenase. Bcd homologs are prevalent in free-living and obligate bacteria but are absent in most, if not all, staphylococci. Despite low sequence homology, Bcd structurally resembles the GudB/RocG family and can functionally compensate for the loss of GudB in S. aureus. Bcd is essential for the full maturation of biofilms. B. subtilis lacking GDHs exhibits severe impairments in rugose architecture and colony expansion of biofilms. This study underscores the importance of metabolic redundancy and highlights the critical role of substrate promiscuity in GDHs during biofilm developmen
Hybrid lattice Boltzmann method for multiphase flows
No full textInternational audienceThis article presents a new hybrid Lattice-Boltzmann method for simulating multiphase. Mean mass and momentum are solved using a Lattice-Boltzmann method, while an order parameter, indicating whether the fluid is gaseous or liquid, is solved by a classical finite volume scheme. The Lattice-Boltzmann scheme is adapted from existing methods using a new equilibrium formulation, as well as new macroscopic reconstructions. The consistency of the resulting scheme is confirmed analytically. Validations are then presented for canonical academic cases, as well as 2D liquid jet simulations yielding different breakup covering dripping, sinuous and atomization regimes
Neural responses underlying ITD discrimination as a function of sensory reliability in the barn owl
No full textInternational audienceAbstract Discrimination of sensory stimuli is fundamentally constrained by the information encoded in neuronal responses. In the barn owl, interaural time difference (ITD) serves as a primary cue for azimuthal sound localization and is represented topographically in the midbrain auditory space map in the external nucleus of the inferior colliculus (ICx). While prior studies have demonstrated a correspondence between spatial tuning and behavioral acuity, it remains unclear how changes in sensory reliability influence this relationship. Here, we examined how behavioral and neuronal ITD discrimination thresholds vary with binaural correlation (BC), which manipulates ITD cue reliability. Using the pupil dilation response (PDR) as a behavioral metric in head-fixed owls, we found that ITD just-noticeable-differences increased exponentially as BC decreased. In contrast, the widths of ICx ITD tuning curves increased more modestly, indicating that tuning resolution alone does not account for behavioral discrimination performance. By computing the Fisher information from ICx neuronal responses, we showed that the average neuronal discriminability predicts behavioral thresholds across BC levels. A habituation-based model incorporating BC-dependent changes in tuning width, firing rate, and response variability successfully accounted for both direction and ITD discrimination. These findings support a model in which perceptual acuity is governed by the combined influence of neuronal tuning and variability and provide a unified framework for understanding how midbrain auditory representations underlie adaptive spatial hearing
Medical management of pancreatic cancer: from personalization to broadening treatment strategies
No full textInternational audiencePancreatic ductal adenocarcinoma (PDAC) is one of the most heterogeneous and deadly cancers. This review examines recently implemented strategies to integrate predictive tools and targeted therapies to improve treatments personalization and patient outcomes. Predictive transcriptomic signatures based on machine learning should optimize first-line chemotherapy selection, while organoid-based chemo-profiling could help late-line or non-standard treatments, particularly when transcriptomic signatures are unavailable to guide therapeutic decisions. Liquid biopsies enable real-time, non-invasive monitoring of tumour progression and resistance. Targeted therapies, even limited to a small subset of PDAC patients, exploit specific molecular vulnerabilities and several of those are under clinical evaluation to join PDAC armamentarium. Given PDAC's biological complexity, a multimodal approach combining predictive tools, functional testing, and molecularly-guided therapies is required to progress. Implementing those strategies in routine practice, combined with technological and clinical advances should enhance the precision, accessibility, and effectiveness of personalized PDAC treatment, as well as expand therapeutic options with new targets
The JWST Early Release Science Program for Direct Observations of Exoplanetary Systems. III. Aperture Masking Interferometric Observations of the Star HIP 65426 at 3.8 <i>μ</i>m
No full textInternational audienceWe present aperture masking interferometry (AMI) observations of the star HIP 65426 at 3.8 μm, as part of the JWST Direct Imaging Early Release Science program, obtained using the Near Infrared Imager and Slitless Spectrograph instrument. This mode provides access to very small inner working angles (even separations slightly below the Michelson limit of 0.5λ/D for an interferometer), which are inaccessible with the classical inner working angles of the JWST coronagraphs. When combined with JWST's unprecedented infrared sensitivity, this mode has the potential to probe a new portion of parameter space across a wide array of astronomical observations. Using this mode, we are able to achieve a 5σ contrast of Δm F380M ∼ 7.62 ± 0.13 mag relative to the host star at separations 0 .07, and the contrast deteriorates steeply at separations 0 .07. However, we detect no additional companions interior to the known companion HIP 65426b (at separation ∼0 .82 or - + 87 au 31 108). Our observations thus rule out companions more massive than 10-12 M Jup at separations ∼10-20 au from HIP 65426, a region out of reach of ground-or space-based coronagraphic imaging. These observations confirm that the AMI mode on JWST is sensitive to planetary mass companions at close-in separations (0 .07), even for thousands of more distant stars 80 Millennium Nucleus on Young Exoplanets and their Moons (YEMS).</div
Pore Structure and Fractal Characteristics in Unconventional Oil and Gas Reservoirs
No full textInternational audienceThis Reprint comprises a collection of articles published in the Special Issue “Pore Structure and Fractal Characteristics in Unconventional Oil and Gas Reservoirs” in Fractal and Fractional, with a focus on the investigation and application of fractal theory to understand the microstructure, transport properties, and acoustic behavior of porous media in unconventional reservoirs. The contributions cover experimental and theoretical studies, including pore space characterization, phase distribution, permeability, and multiscale modeling using fractals, while advanced techniques, such as acoustic and ultrasonic measurements, fractional derivatives, and poroelastic modeling, are highlighted to improve the understanding of fluid flow, mechanical behavior, and sound absorption in complex materials. This Reprint aims to provide researchers and engineers with a comprehensive reference for the application of fractal-based methods in geological, geophysical, and engineering contexts
L’effet du répertoire linguistique et de l’ordre d’acquisition sur le traitement en L3 : le cas des apprenants de L3 espagnol ayant le français comme L1 ou L2 et ceux ayant le mandarin comme L1
No full textInternational audienceThird language acquisition (L3A) differs from the acquisition of a first (L1) or second (L2) language, particularly at the initial stages of proficiency, in part due to cross-linguistic influence (CLI) (e.g., Bot & Jaensch, 2015; Jarvis & Pavlenko, 2008; Ringbom, 2007) and structural similarity (e.g., Westergaard, 2017). This study aims to investigate the extent to which one’s prior linguistic repertoire is relevant in third language (L3) learning by examining how the presence or absence of French, as another gendered language, and its order of acquisition (L1 vs. L2), may affect accuracy and task completion times with grammatical gender in L3 Spanish by analyzing: (i) structural similarity in terms of grammatical gender, (ii) order of acquisition of the structurally similar language, and (iii) cross-linguistic structural congruency for grammatical gender assignment. A total of 115 adults were recruited and divided according to their linguistic background: L1 English-L2 French (n=27), L1 French-L2 English (n=37), L1 Mandarin-L2 English (n=31), and L1 Spanish speakers (n=20) as a control group. All participants were fluent in English and completed a language background questionnaire, a Spanish proficiency test, and four experimental tasks targeting article-noun-adjective gender agreement in L3 Spanish. The tasks were: (1) an oral translation task from participants' respective L1 to L3 Spanish, (2) a picture identification task pairing noun phrases with corresponding images to complete descriptive sentences, (3) a picture description task where participants paired objects with a number or color word depicted in images, and (4) a grammaticality choice task requiring participants to identify target-like noun-adjective and article-noun agreement phrases. Experimental stimuli contrasted congruent (e.g., “la-fem. mesa-fem. blanca-fem.” / “la-fem. table-fem. blanche-fem.”, the white table) and incongruent (e.g., “la-fem. cama-fem. roja-fem.” / “le-masc. lit-masc. rouge-masc.”, the red bed) tokens. Accuracy scores and total task completion times were recorded for each task. Findings show that beginner learners with a French background (L1/L2) significantly outperformed Mandarin-English speakers in both accuracy and task completion speed, with the most substantial differences observed on cross-linguistically congruent tokens in gender assignment between French and Spanish. Accounting for a gendered background, beginner L1 French speakers exhibited significantly higher accuracy than beginner L2 French speakers, highlighting the effect of order of acquisition on cross-linguistic transfer. Notably, congruency effects were stronger for L1 French participants, who were more accurate when processing gender-congruent tokens compared to incongruent ones. Conversely, incongruence reduced accuracy across both gendered background groups, highlighting the complexity of integrating similar linguistic structures during L3 acquisition. No significant language background effects were detected in advanced proficiency learners. This study makes a novel contribution to the growing field of third language acquisition by examining how both linguistic repertoire and acquisition order impact morphosyntactic transfer in L3, emphasizing the importance of structural similarity while also illustrating how proficiency interacts with congruency effects in determining the degree of transfer. In sum, this study provides evidence for the source of transfer being conditioned by order of acquisition and cross-linguistic congruency in L3 morphosyntactic development through an analysis of mirror-image groups and a non-gendered comparison group.L’acquisition d’une troisième langue (L3A) se distingue de l’acquisition d’une première (L1) ou d’une deuxième langue (L2), notamment aux stades initiaux de compétence, en partie en raison de l’influence translinguistique (CLI) (par ex., Bot & Jaensch, 2015 ; Jarvis & Pavlenko, 2008 ; Ringbom, 2007) et de la similarité structurelle entre les langues (par ex., Westergaard, 2017). La présente étude vise à examiner dans quelle mesure le répertoire linguistique préalable d’un individu joue un rôle dans l’apprentissage d’une troisième langue (L3), en analysant comment la présence ou l’absence du français — en tant qu’autre langue marquée par le genre grammatical — ainsi que son ordre d’acquisition (L1 vs. L2) peuvent influencer la précision et les temps d’exécution de tâches portant sur le genre grammatical en espagnol L3. Trois dimensions sont analysées : (i) la similarité structurelle en matière de genre grammatical, (ii) l’ordre d’acquisition de la langue structurellement similaire, et (iii) la congruence structurelle translinguistique pour l’attribution du genre grammatical.Au total, 115 adultes ont été recrutés et répartis selon leur profil linguistique : L1 anglais–L2 français (n = 27), L1 français–L2 anglais (n = 37), L1 mandarin–L2 anglais (n = 31), et un groupe témoin de locuteurs natifs de l’espagnol (n = 20). Tous les participants étaient anglophones compétents et ont complété un questionnaire de profil linguistique, un test de compétence en espagnol, ainsi que quatre tâches expérimentales portant sur l’accord en genre entre l’article, le nom et l’adjectif en espagnol L3. Les tâches comprenaient : (1) une tâche de traduction orale de la L1 vers l’espagnol L3, (2) une tâche d’identification d’images consistant à associer des syntagmes nominaux à des images pour compléter des phrases descriptives, (3) une tâche de description d’images où les participants devaient associer des objets à un nombre ou à une couleur figurant sur les images, et (4) une tâche de jugement de grammaticalité requérant l’identification de syntagmes corrects en termes d’accord nom-adjectif et article-nom. Les stimuli expérimentaux opposaient des formes congruentes (par ex. : la-fém. mesa-fém. blanca-fém. / la-fém. table-fém. blanche-fém. — « la table blanche ») et incongruentes (par ex. : la-fém. cama-fém. roja-fém. / le-masc. lit-masc. rouge-masc. — « le lit rouge »). Les scores de précision et les temps totaux d’exécution ont été enregistrés pour chaque tâche.Les résultats montrent que les apprenants débutants ayant une connaissance du français (L1 ou L2) ont significativement surpassé les locuteurs mandarin-anglais en précision comme en rapidité d’exécution, les différences les plus marquées apparaissant pour les items congruents entre le français et l’espagnol en matière d’attribution du genre. En tenant compte du statut de langue genrée, les locuteurs natifs de français (L1) ont obtenu des scores de précision significativement plus élevés que les apprenants dont le français est une L2, soulignant ainsi l’effet de l’ordre d’acquisition sur le transfert translinguistique. Notamment, les effets de congruence étaient plus prononcés chez les participants L1 français, plus précis dans le traitement des items congruents que des items incongruents. À l’inverse, l’incongruence a diminué la précision dans les deux groupes ayant une langue genrée, illustrant la complexité de l’intégration de structures similaires au cours de l’acquisition d’une L3. Aucun effet significatif du profil linguistique n’a été observé chez les apprenants avancés.Cette étude apporte une contribution originale au domaine en expansion de l’acquisition d’une troisième langue en montrant comment le répertoire linguistique et l’ordre d’acquisition influencent le transfert morphosyntaxique en L3. Elle met en évidence l’importance de la similarité structurelle, tout en illustrant la manière dont la compétence interagit avec les effets de congruence pour déterminer le degré de transfert. En somme, les résultats confirment que la source du transfert est conditionnée à la fois par l’ordre d’acquisition et par la congruence translinguistique dans le développement morphosyntaxique en L3, à travers l’analyse de groupes en miroir et d’un groupe de comparaison non genré