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Refining near-infrared spectroscopy for collagen quantification: A new predictive model for archaeological bone
No full textInternational audienceCollagen is a vital archaeological material, preserving biochemical signatures that provide insights into past environments, diets, and human-animal interactions. However, diagenesis can lead to rapid and inconspicuous collagen degradation. Given the variability in collagen preservation and its significance for analyses such as radiocarbon dating, stable isotope analysis, and ZooMS, researchers have developed prescreening techniques to assess collagen preservation before destructive sampling. Current prescreening approaches, including %N and C:N ratios, typically require sample destruction and access to equipped laboratories. Spectroscopic techniques such as Raman spectroscopy and Fourier Transform Infrared spectroscopy have been explored as alternatives, but they are limited in penetration depth, generalizability (at present at least), and are often still destructive, if minimally.Here, we further develop single-point near-infrared (NIR) spectroscopy as a fully non-destructive, rapid, and field-portable method for prescreening bone for collagen preservation. Unlike FTIR and Raman spectroscopic techniques, NIR light penetrates below the surface of bone, enabling assessment of internal collagen preservation without destructive sample preparation. Using Partial Least Squares Regression (PLSR) and Random Forest (RF) modeling, we trained predictive models on whole bones with known collagen yields and validated the models on an independent archaeological collection. Both PLSR and RF models, when restricted to the 2030–2060 nm range, demonstrate strong and comparable performance while avoiding wavelengths associated with consolidants in our reference library. The models outperform traditional % N-based methods in identifying suitable samples for radiocarbon dating. These models enable the high-throughput screening of large collections of bone, improving sample selection and minimizing unnecessary destructive analysis
GWTC-4.0: Searches for Gravitational-Wave Lensing Signatures
No full textInternational audienceGravitational waves can be gravitationally lensed by massive objects along their path. Depending on the lens mass and the lens--source geometry, this can lead to the observation of a single distorted signal or multiple repeated events with the same frequency evolution. We present the results for gravitational-wave lensing searches on the data from the first part of the fourth LIGO--Virgo--KAGRA observing run (O4a). We search for strongly lensed events in the newly acquired data by (1) searching for an overall phase shift present in an image formed at a saddle point of the lens potential, (2) looking for pairs of detected candidates with consistent frequency evolution, and (3) identifying sub-threshold counterpart candidates to the detected signals. Beyond strong lensing, we also look for lensing-induced distortions in all detected signals using an isolated point-mass model. We do not find evidence for strongly lensed gravitational-wave signals and use this result to constrain the rate of detectable strongly lensed events and the merger rate density of binary black holes at high redshift. In the search for single distorted lensed signals, we find one outlier: GW231123_135430, for which we report more detailed investigations. While this event is interesting, the associated waveform uncertainties make its interpretation complicated, and future observations of the populations of binary black holes and of gravitational lenses will help determine the probability that this event could be lensed
Beryllium 10 in Antarctica over the last seven millennia
No full textInternational audienceSince the first measurements of beryllium 10 (10Be) in ice, in the seventies, numerous profiles of this cosmogenic isotope have been obtained both in Antarctica and Greenland. In this article, we focus on Antarctic data, available at nine different sites, covering a significant part of the Holocene, from 237 to 7101 yr BP. We show that correlating their 10Be profiles allows to synchronize these ice cores with an excellent accuracy and to document the spatial variability of 10Be concentration and flux. We then examine how this variability is taken into account by a simulation of 10Be fallout recently performed with the ECHAM6.3-HAM2.3 model. Except for a systematic underestimation of 10Be fluxes at high accumulation sites, these simulations are overall very satisfying. Finally the excellent accuracy of synchronisation based on 10Be profiles allows us to derive an Antarctic stack record over the last seven millennia. The reliability of the new 10Be stack is demonstrated by its superior correspondence with the accurately dated IntCal20 record based on 14C in tree rings
Archaeological and rock art evidence of the horse in the prehistoric western Himalayas and the Tibetan plateau
No full textInternational audienc
Short time and local spatial scale estimation of sedimentary volumes during the Little Ice Age from sparse data: Case of a Rhône delta palaeochannel (France)
No full textInternational audienceEstimating sediment volumes from fossil fluvial overbank deposits remains challenging, particularly at fine spatial and temporal scales in complex morphologies. This study focuses on a ~7 km 2 concave bank of the Grande Ponche palaeomeander (Rhône Delta, France), where rapid overbank deposition occurred over ~20 years during the Little Ice Age (LIA). Two modelling approaches are evaluated for reconstructing deposit thickness with sinuous geometry from sparse datasets: Discrete Smooth Interpolation (DSI), and kriging applied on a complex grid allowing curvilinear anisotropy to be reproduced. Both approaches yielded similar volume estimates (~0.009-0.01 km 3 ), showing overbank deposits (~0.004 km 3 , ~3.15 mm/yr) and floodplain aggradation (~0.006 km 3 , ~1.43 mm/yr). Compared to conventional techniques, DSI and kriging provided more realistic 3D models capturing spatial anisotropy and proximo-distal thickness gradients, hence prefiguring better sediment volume estimation. Bootstrapping results show volume estimates less sensitive to spatial distribution of sparse data. DSI enabled the reconstruction of levee and crevasse splay within overbank deposits from a minimal dataset. Kriging requires denser data to obtain suitable variograms and then did not achieve these detailed models. However, when applicable, it allows for volume estimate uncertainty that DSI does not provide. The finescale sediment volumes at the Grande Ponche reveal the disproportionate geomorphological impact of short-term LIA flood, with aggradation rates far exceeding Holocene and modern Rhône delta averages. These results show that brief intense climatic phases can generate important but spatially localised sediment storage. Improved quantification of such short-term sedimentary pulses strengthens source-to-sink analyses and refines our understanding of sedimentary responses to climatic variability in fluvial-deltaic systems.</div
Fouilles programmées 2023 sur le site de Balchiria (Sartène, Corse du sud) : un centre cérémoniel de l’horizon pré-mégalithique
No full textNational audienceLa découverte fortuite, en 2016, de deux stèles, dont une présentant une iconographie inédite en Méditerranée, a motivé la mise en place d’une série d’opérations de fouilles programmées sur le site de Balchiria, sur la communede Sartène, en Corse-du-Sud. Les opérations conduites entre 2020 et 2023 sous la codirection de la DRAC de Corse et l’Université de Strasbourg, ont permis de contextualiser ces monuments en mettant en évidence plusieursarchitectures de pierres dont certaines peuvent être identifiées à des podiums. Le plus spectaculaire d’entre-deux, de plan naviforme, a conservé une douzaine de petits monolithes découverts en place, encore dressés ou légèrement inclinés. Deux aires empierrées voisines, de plan circulaire ou quadrangulaire sont, en toute hypothèse, assimilées soit à des podiums, soit à des aires cérémonielles
« La « Sanniangzi » (« Troisième Dame »)/Jönggen qatun (1551-1612) : reine mongole sage et pro-chinoise, d’après les sources chinoises »
No full textInternational audienceJönggen qatun, connue en chinois sous le nom de « Sanniangzi » (Troisième Dame) est la dernière grande reine des steppes. Sa vie est documentée dans des sources chinoises de la fin des Ming (1368-1644), qui lui attribuent l’initiative des accords de paix de 1570, et la décrivent comme belle, lettrée et sage. Lorsque son époux, le puissant Altan qan, décède en 1582, Jönggen gouverne de facto, mais l’héritier légitime est le fils de la première épouse d’Altan, Sengge Dügüreng. Les Ming, qui considèrent la Sanniangzi comme « pro-chinoise », ne voient qu’une solution pour garantir la paix et le commerce frontalier : malgré leur profonde aversion pour la pratique mongole du lévirat qu’ils jugent incestueuse, ils demandent à la Sanniangzi d’épouser Senge Dügüreng ; puis son fils, enfin son arrière-petit-fils après le décès de chaque héritier. Comment les Chinois peuvent-ils louer la sagesse d’une reine « barbare » dans une société confucéenne patriarcale ? Cet article s’intéresse à l’image de la Sanniangzi sous les Ming et à ses représentations contemporaines. Au XXIe siècle, elle symbolise l’amitié entre les ethnies han et mongoles de Chine, et est célébrée dans des romans et des opéras
Actualités respiratoires 2025 Présentée par Justine Frija (MCU-PH à l’université Paris Cité et à l’AP-HP).
No full textAs part of Respiratory News 2025, at the Sleep Congress in Strasbourg, a thematic summary of recent publications was produced by Justine Frija, MCU-PH at Paris Cité University and AP-HP, focusing on results with a direct impact on the clinical management of obstructive sleep apnea syndrome (OSAS), particularly in patients treated with continuous positive airway pressure (CPAP). The selected studies cover quality of life under CPAP, adherence and care pathways, the reliability of devices and residual indices, the cardiometabolic consequences of OSA, and public health perspectives incorporating changes in prevalence and the effects of climate change.Dans le cadre des Actualités respiratoires 2025, au Congrès du Sommeil à Strasbourg, une synthèse thématique de publications récentes a été réalisée par Justine Frija, MCU-PH à l’université Paris Cité et à l’AP-HP, centrée sur des résultats ayant un impact direct sur la prise en charge clinique du syndrome d’apnées obstructives du sommeil (SAOS), en particulier chez les patients traités par pression positive continue (PPC). Les travaux sélectionnés couvrent successivement la qualité de vie sous PPC, l’adhérence et la trajectoire de soins, la fiabilité des dispositifs et des indices résiduels, les conséquences cardiométaboliques du SAOS, ainsi que des perspectives en santé publique intégrant l’évolution de la prévalence et les effets du changement climatique
Repeated losses of self-fertility shaped heterozygosity and polyploidy in the evolution of Saccharomyces cerevisiae
No full textInternational audienceTransitions in mating strategy have profound consequences for genetic variation and adaptation. In Saccharomyces cerevisiae, mating-type switching is a central feature of the life cycle that enables homothallism, i.e., mating between mitotic descendants of the same haploid cell. Yet heterothallic isolates that have lost this ability are found across diverse niches. Here we experimentally characterized loss of mating-type switching in a representative panel of strains. Analysis of 117 telomere-to-telomere genome assemblies revealed multiple independent loss-of-function mutations in the Ho endonuclease gene, which is essential for switching. We estimated that at least 13 independent transitions from homothallism to heterothallism have occurred in the species history. Analysis of the HO genotype of 2,915 strains showed that at least 27% are heterothallic. We found that heterothallism is associated with polyploidy and elevated genome-wide heterozygosity, although the strength of these associations varies between populations. Heterothallic isolates are most prevalent in domesticated and clinical clades, consistent with an origin linked to human-associated environments. Signatures of recombination in HO sequences suggest that outcrossing contributed to the ecological and geographical distribution of the trait. Our findings reveal that mating-type switching has undergone repeated losses in S. cerevisiae evolution, with major consequences for genome architecture and ecological diversification