Hal - Université Grenoble Alpes
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Ti and Ni-based BEOL CMOS-compatible P+-InGaAs ohmic contacts for the future of wireless communications
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Squeezed waveguides as a framework to study vowel-like acoustic resonances
No full textInternational audienceThe relationship between vocal tract geometry and acoustic resonances is often examined using speaker-specific data, limiting physical studies to a narrow set of static, rigid configurations and frequently producing discontinuous area functions that are poorly suited for studying dynamic vocal-tract behavior. To address these constraints, this study introduces a theoretical squeezed waveguide vocal tract (SWVT) framework for analyzing the relationship between acoustic resonances (up to 4–5 kHz) and smooth area functions that characterize vowel-like vocal tract configurations with one or two constrictions. The relevance of seven SWVT parameters—constriction positions, degrees, extents, and waveguide length—is established through theoretical analysis and experimental validation. Experiments are performed using both rigid, static waveguides and a deformable, molded waveguide. The molded waveguide facilitates experimental investigation of constriction degrees up to full closure and provides a basis for future studies on the (aero-)acoustic–geometry relationship in dynamic SWVT configurations
Global convergence in wood evolution is driven by drought on continents and frost-free temperatures on islands
No full textPhylogenetically derived woodiness (DW), the evolutionary reversion from herbaceousness to woodiness in angiosperms, is one of the most conspicuous characteristics of (sub)tropical island floras. Here, we show that DW across continents is more common than previously thought, especially in frost-free and open habitats with pronounced seasonal drought. Using a novel dataset on the evolution of woodiness in angiosperms, we discovered substantially more derived woody species (DWS) and independent evolutionary transitions on continents compared to islands (4,808 species and 513 transitions vs. 1,084 and 175, respectively). However, we identified more insular DWS hotspots (22) than the four continental DWS hotspots: the Andes, Southern Africa, the Old-World Dry Belt and Australia. A structural equation model controlling for total species richness suggests that aridity is the strongest predictor of the number of DWS on continents, while frost-free temperatures best predict DWS on islands. Precipitation seasonality and mean elevation emerge as additional significant predictors in both cases, with a further potential role for light-prone open habitats. In summary, the diverse global drivers behind the hundreds of independent woodiness shifts highlight the existence of various mechanisms that lead to increased wood formation in stems, confirming its adaptive value over evolutionary time
Rapport sur les services climatiques réussis dans le monde et leurs critères de succès: Livrable commun au Projet ciblé TRACCS-PC1-DIALOG (D5.3) et au Projet Ciblé TRACCS-PC3-DEMOCLIMA (D1)
No full textLes enjeux socio-économiques liés aux effets du réchauffement climatique sont tels qu’une demande croissante d’informations climatiques adaptées pour la mise en place de stratégies d’atténuation et/ou d’adaptation est clairement exprimée par les secteurs économiques (e.g. agriculture, énergie, tourisme, infrastructures terrestres ou maritimes, etc…) et par les territoires/régions qui mesurent pleinement leursvulnérabilités. En réponse à ces demandes, de nombreux projets de recherche nationaux (e.g., la "Convention relative à l’attribution d’un appui financier au bénéfice des services climatiques", signée entre le Ministère de la Transition Écologique et Solidaire (MTES) et le CNRS en mars 2017, ou le développement du portail DRIAS), européens (e.g., le programme ERA4CS « European Research Area for Climate Services » du JPI Climate, ou encore Copernicus) ou internationaux (e.g., les outils développés par la NASA, le GIEC…) ont permis le financement de « services climatiques ». Plusieurs acteurs opérationnels nationaux et européens développent et mettent à disposition des « services climatiques » via des plateformes souvent libres d’accès et enfin, apparaissent sur le marché des bureaux d’études dont l’activité commerciale vise le développement de « services climatiques » à la carte et adaptés aux demandes des clients.L’offre pour les « services climatiques » est donc aujourd’hui multiforme par l’information fournie (données climatiques « simples », indicateurs, outils d’aide à la décision) et par son mode de développement. Face à cette diversité, les enjeux sont de documenter et comprendre le paysage des services climatiques actuels, de faire ressortir les besoins, et de se munir de moyens pour caractériser la réussite des services climatiques, pour évaluer l'existant et guider le développement de nouveaux projets. Menée conjointement par les projets ciblés DIALOG (PC1) et DEMOCLIMA (PC3) du PEPR TRACCS, cette étude vise quatre objectifs :i) Documenter le paysage actuel des services climatiques (section 2) en France et dans le monde (identifiés par la communauté TRACCS) en les présentant par usages et cibles ;ii) Identifier des besoins non satisfaits vis-à-vis des services climatiques (section 4) ;iii) Identifier un ensemble de critères de réussite d'un service climatique pour les évaluer (section 5) ;iv) Proposer des bonnes pratiques pour atteindre ces critères de réussite (section 6); ces éléments guideront les choix des futurs démonstrateurs qui seront conçus et développés au sein de DEMOCLIMA.Notre travail repose en grande partie sur le recueil de dires d'acteurs des "services climatiques", dans une approche "bottom-up"
Un rôle de genre en faveur d'une éducation physique "féminine" : Jacqueline Roger
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Magneto-Optical Readout of a Chiral Single-Molecule Magnet at Telecom Wavelengths
No full textInternational audienceIn this work, the wavelength range of magneto-chiral dichroism (MChD) based optical readout of magnetic hysteresis is extended to the near-infrared (NIR) telecom communication range where optical fibers have the smallest transmission loss. To achieve this goal, we have prepared and investigated a new air-stable chiral single-molecule magnet (SMM) formulated as (S)- and (R)-[Dy(bbppn)Cl] (bbppn = N,N'-bis(2-hydroxybenzyl)-N,N'-bis(2-pyridylmethyl)-X-1,2-propanediamine, X = S, R). We demonstrate that the magnetic hysteresis of this SMM, despite exhibiting rapid quantum tunneling of magnetization (QTM) at zero field, can be optically detected using unpolarized light through MChD. Complementary to our seminal study limited to the visible spectral range, we demonstrate that the MChD-based readout is also effective for the Dy(III) f-f transitions in the NIR region, confirming the robustness of this method across a broader spectral window. These findings establish MChD as a generalizable optical readout method for molecular magnetic materials, reinforcing its potential for future applications in polarization-free optical data readout technologies and optical communication at telecom wavelengths
Large-scale genome-wide association study of 398,238 women unveils seven novel loci associated with high-grade serous epithelial ovarian cancer risk
No full textInternational audienceABSTRACT Background Nineteen genomic regions have been associated with high-grade serous ovarian cancer (HGSOC). We used data from the Ovarian Cancer Association Consortium (OCAC), Consortium of Investigators of Modifiers of BRCA1 / BRCA2 (CIMBA), UK Biobank (UKBB), and FinnGen to identify novel HGSOC susceptibility loci and develop polygenic scores (PGS). Methods We analyzed >22 million variants for 398,238 women. Associations were assessed separately by consortium and meta-analysed. OCAC and CIMBA data were used to develop PGS which were trained on FinnGen data and validated in UKBB and BioBank Japan Results Eight novel variants were associated with HGSOC risk. An interesting discovery biologically was finding that TP53 3’-UTR SNP rs78378222 was associated with HGSOC (per T allele relative risk (RR)=1.44, 95%CI:1.28-1.62, P=1.76×10 -9 ). The optimal PGS included 64,518 variants and was associated with an odds ratio of 1.46 (95%CI:1.37-1.54) per standard deviation in the UKBB validation (AUROC curve=0.61, 95%CI:0.59-0.62). Conclusions This study represents the largest GWAS for HGSOC to date. The results highlight that improvements in imputation reference panels and increased sample sizes can identify HGSOC associated variants that previously went undetected, resulting in improved PGS. The use of updated PGS in cancer risk prediction algorithms will then improve personalized risk prediction for HGSOC
Les contraintes internes contrôlent la dynamique d’enroulement des vrilles chez les plantes grimpantes
No full textInternational audiencePlant tendrils are mechanosensitive and highly motile organs known for touch-induced differential growth. The resulting coiling dynamics under external traction reveal that non-homogeneous internal stress over the tendril cross-section is fundamental to understanding the system. External loading inhibits curvature generation and can fully suppress it above a threshold force. Remarkably, however, the internal differential stress onset persists even under the highest applied traction forces.We develop an autotropic morphoelastic growth (AMG) model, grounded in a bi-strip geometry and Kirchhoff rod theory, which capture these main features. In particular, the AMG model reproduces the observed 1/4 ratio between the generated intrinsic curvature at high force and that at zero force. According to the AMG model, this ratio depends solely on the twist-to-bend ratio, which is a parameter determined by the plant species.Les vrilles des plantes sont des organes mécanosensibles et hautement mobiles, connus pour leur croissance différentielle induite par le contact. La dynamique d’enroulement sous traction externe montre que la présence de contraintes internes non homogènes à travers la section de la vrille est essentielle pour comprendre le système. La charge externe inhibe la génération de courbure et peut même la supprimer complètement au-delà d’une force seuil. Il est toutefois remarquable que l’apparition de contraintes différentielles internes persiste, même sous les forces de traction les plus élevées appliquées.Nous développons un modèle de croissance morphoélastique autotropique (AMG), fondé sur une géométrie de type bi-lame et sur la théorie des tiges de Kirchhoff, qui rend compte de ces caractéristiques principales. En particulier, le modèle AMG reproduit le rapport expérimental de 1/4 entre la courbure intrinsèque générée sous forte traction et celle observée en l’absence de force. Selon le modèle AMG, ce rapport dépend uniquement du rapport torsion–flexion, un paramètre déterminé par l’espèce végétale
3D simulation of charge defect impact on an industrial 28 nm FD-SOI quantum dot
No full textInternational audienceThe emergence of cryo-electronics and quantum applications has shown that experiments involving quantum dots are highly sensitive to disorder and variability. This sensitivity offers the opportunity to detect and classify defects, evaluate process quality in detail, and guide the enhancement of robustness. In this preliminary work, we explore the 3D quantum simulation of an industrial FD-SOI quantum dot device, with and without a charge defect
Experimental and numerical investigation of the impact force generated by cylindrical ice water pellets
No full textInternational audienceThis study focuses on the force-time response of cylindrical water ice specimens subjected to impact loadings. Spherical specimens are traditionally used to characterize the impact behavior of water ice. However, they cannot be used to study the geometric effects induced by a cylindrical shape. Impact tests were carried out on a Hopkinson bar at 30 m.s -1 . These tests have demonstrated the importance of the impact angle in terms of both the increase in the load and the peak force at impact. Contrarily to what was observed for tensile spalling test, porosity has no noticeable impact on the maximum peak force measured here. The importance of the impact angle is illustrated by comparing the mechanical response of ice spheres with pellet cylinders for equivalent kinetic energies and temperatures