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MIRI Deep Imaging Survey (MIDIS) of the Hubble Ultra Deep Field
No full textInternational audienceThe recently launched James Webb Space Telescope (JWST) is opening new observing windows on the distant universe. Among JWST's instruments, the Mid Infrared Instrument (MIRI) offers the unique capability of imaging observations at wavelengths \lambda > 5\mum. This enables unique access to the rest frame near infra-red (NIR, \mum) emission from galaxies at redshifts z>4 and the visual (Å) rest frame for z>9. We here report on the guaranteed time observations (GTO) from the MIRI European Consortium, of the Hubble Ultra Deep Field (HUDF), forming the MIRI Deep Imaging Survey (MIDIS), consisting of an on source integration time of hours in the MIRI/F560W (5.6 m) filter. To our knowledge, this constitutes the longest single filter exposure obtained with JWST of an extragalactic field as yet
A space-time approach for the simulation of brittle fracture with phase-field models in elastodynamics
No full textInternational audienceA space-time approach is proposed to simulate the propagation of brittle cracks in an isotropic and elastic solid in dynamics. We adopt the so called phase-field description of crack that is based on a variational representation of fracture mechanics. Due to this variational structure, the crack initiation and propagation can be then described thanks to a well chosen potential. In this approach, we propose to consider a space-time potential to derive the appropriate Euler equations on the space-time domain. A time discontinuous Galerkin approach is used and adapted to damage and elastodynamics such as to be able to account of time singularities in the considered fields. This approach follows a previous work done on elastodynamics (see [47]) in which we have proposed a stabilized formulation with the help of least square terms. The proposed space-time potential is discretized with either standard finite-elements (ST-FE) or isogeometric analysis (ST-IGA). We apply this approach to different numerical examples including dynamic fragmentation
Mediterranean islands as refugia for elasmobranch and threatened fishes
No full text\ₑprint: https://onlinelibrary.wiley.com/doi/pdf/10.1111/ddi.13937International audienceAim The Mediterranean Sea is one of the most anthropized seas in the world but also a marine biodiversity hotspot with many fish species under threat. The main goal of the study is to test whether on the heavily fished and anthropized Mediterranean coast, the less impacted Corsica and Balearic Islands, can be considered as refugia for threatened and elasmobranch fishes independently of protection by marine reserves. Location The French Mediterranean coast and three north-western Mediterranean islands: Corsica and also Mallorca and Minorca from the Balearic archipelago. Methods We performed 187 fish surveys using environmental DNA metabarcoding on three islands and 109 along the continental coast. Of the 78 surveys on islands 22 correspond to no-take marine reserves and of the 109 continental surveys 26 were carried out within reserves. After eDNA filtration, extraction, amplification, and sequencing we estimated the number of fish species but also the number commercial, threatened and elasmobranch fish species on each sample. We then performed an ANOVA by permutation to test the effect of insularity and protection on these four biodiversity metrics. We also modelled these four biodiversity metrics as a function of protection and human pressure but also environmental, habitat and sampling conditions. We also built species accumulation curves to obtain asymptotes representing the potential regional pools for each species category on both island and continental coasts. Results We obtained a total of 175,982,610 reads over the 187 eDNA samples that were assigned to 153 fish species including 17 elasmobranch species among which 7 were only detected on islands. We observed a higher total fish richness on continental than island surveys regardless of protection but a higher threatened and elasmobranch fish richness on the island than on continental surveys. We obtained a significant, negative and predominant human gravity impact on the diversity of elasmobranch species. The modelled asymptote reached 148 teleostean fish species on islands and 196 on the continental coastline with a very similar rate of diversity increase with sampling effort but the shape of the species accumulation curves differed markedly for elasmobranchs with a stronger increase in diversity with sampling effort on islands. Main Conclusions Our findings highlight that Mediterranean islands can be refugia for sharks and rays but also threatened fishes in this overexploited region. Our results also suggest that reducing or banning trawling activities may play a key role for conserving vulnerable fishes, beyond the benefits of no-take marine reserves, which appear limited on these large home-range species
DESI 2024 V: Full-Shape Galaxy Clustering from Galaxies and Quasars
No full textInternational audienceWe present the measurements and cosmological implications of the galaxy two-point clustering using over 4.7 million unique galaxy and quasar redshifts in the range $0.
Un guide pratique sur les méthodes physicochimiques et biologiques pour le développement de systèmes d'administration de médicaments polymères : les vecteurs antipaludiques comme étude de cas
No full textInternational audienceMacromolecular drug delivery systems are engineered nanotechnologies used for the targeted delivery and controlled release of therapeutic agents to a specific biologic target, a rapidly growing need in the age of tailor-made therapeutic treatments. The rise of drug delivery systems stems from their ability to solve the pharmacological issues that often impede the drug development process. The aim of this review is to provide a detailed how-to guide through the early stages of the discovery of new drug-loaded nanocarriers. From their synthesis to their biological evaluations, their development requires multidisciplinary knowledge of chemistry, physics, and biology and involves mastering leading-edge technological equipment. The essential steps and techniques are thus described and discussed in the context of the preparation, physicochemical characterization, and biological study of polymeric drug delivery systems. This guide is intended as a comprehensive and didactic resource to assist (bio)chemists, (bio)physicists, and biologists, as well as beginners, in their work and discussions on polymeric nanocarriers. Although this review addresses general themes applicable to all polymeric nanocarriers, the implementation of these different physicochemical and biological strategies is highlighted through the concrete case of antimalarial-drug vectorizatio
Measurement of CP asymmetry in decays
No full textInternational audienceA measurement of the CP-violating parameters in BsDsK decays is reported, based on the analysis of proton-proton collision data corresponding to an integrated luminosity of at a centre-of-mass energy of . The measured parameters are , , , and , where the first uncertainty is statistical and the second systematic. Together with the value of the Bs mixing phase , these parameters are used to obtain a measurement of the CKM angle equal to modulo , where the uncertainty contains both statistical and systematic contributions. This result is combined with the previous LHCb measurement in this channel using resulting in a determination of
Cylindres en chute libre dont le rapport longueur/diamètre est de l'ordre de l'unité
No full textInternational audienceThe paper presents numerical simulations of the free fall of homogenous cylin- ders of length to diameter ratios 0.8 through 1.6 and solid to fluid density ratios ρs/ρ going from 0 to 5 in transitional regimes. The results shed light on the transition from flat cylinders falling with their axis oriented vertically or oscillating about this equilibrium position to oblong cylinders keeping a horizontal or predominantly horizontal orientation. A significant bi-stability region extending as much as to an interval of L/d ratios of 0.9 ≤ L/d ≤ 1.35 shortly before the onset of path instabilities has been evidenced. With the onset of path instabilities, the scenario starts to depend on the density ratio and the bi-stability domain progressively disappears. In these regimes, cylin- ders of legth to diameter ratio 0.9 and 1 are observed to change periodically or intermittently the orientation of their axis. Cylinders of ratio L/d = 1.6 behave qualitatively like those of ratio L/d ≥ 2 investigated elesewhere and present subritical effects for density ratio of 5.L'article présente des simulations numériques de la chute libre de cylindres homogènes de rapports longueur/diamètre (L/d) compris entre 0,8 et 1,6 et de rapports de masses volumiques solide/fluide ρs/ρ allant de 0 à 5 dans des régimes de transition. Les résultats mettent en lumière la transition de cylindres plats tombant avec leur axe orienté verticalement ou oscillant autour de cette position d'équilibre vers des cylindres oblongs gardant une orientation horizontale ou principalement horizontale. Une région de bistabilité significative s'étendant jusqu'à un intervalle de rapports L/d 0,9 à 1,35 peu avant le début des instabilités de trajectoire a été mise en évidence. Avec le début des instabilités de trajectoire, le scénario commence à dépendre du rapport de masses volumiques et le domaine de bistabilité disparaît progressivement. Dans ces régimes, on observe que les cylindres de rapport longueur/diamètre 0,9 et 1 changent périodiquement ou par intermittence l'orientation de leur axe. Les cylindres de rapport L/d = 1,6 se comportent qualitativement comme ceux de rapport L/d ≥ 2 étudiés ailleurs et présentent des effets sous-critiques pour un rapport de masses volumiques égal à 5
Euclid: Early Release Observations of diffuse stellar structures and globular clusters as probes of the mass assembly of galaxies in the Dorado group
No full textInternational audienceDeep surveys reveal tidal debris and associated compact stellar systems. Euclid's unique combination of capabilities (spatial resolution, depth, and wide sky coverage) will make it a groundbreaking tool for galactic archaeology in the local Universe, bringing low surface brightness (LSB) science into the era of large-scale astronomical surveys. Euclid's Early Release Observations (ERO) demonstrate this potential with a field of view that includes several galaxies in the Dorado group. In this paper, we aim to derive from this image a mass assembly scenario for its main galaxies: NGC 1549, NGC 1553, and NGC 1546. We detect internal and external diffuse structures, and identify candidate globular clusters (GCs). By analysing the colours and distributions of the diffuse structures and candidate GCs, we can place constraints on the galaxies' mass assembly and merger histories. The results show that feature morphology, surface brightness, colours, and GC density profiles are consistent with galaxies that have undergone different merger scenarios. We classify NGC 1549 as a pure elliptical galaxy that has undergone a major merger. NGC 1553 appears to have recently transitioned from a late-type galaxy to early type, after a series of radial minor to intermediate mergers. NGC 1546 is a rare specimen of galaxy with an undisturbed disk and a prominent diffuse stellar halo, which we infer has been fed by minor mergers and then disturbed by the tidal effect from NGC 1553. Finally, we identify limitations specific to the observing conditions of this ERO, in particular stray light in the visible and persistence in the near-infrared bands. Once these issues are addressed and the extended emission from LSB objects is preserved by the data-processing pipeline, the Euclid Wide Survey will allow studies of the local Universe to be extended to statistical ensembles over a large part of the extragalactic sky
Cyclotron emitting magnetic white dwarfs in post common envelope binaries discovered with the Zwicky Transient Facility
No full textInternational audienceWe present the discovery of 14 new (and recovery of 4 known) low accretion rate magnetic white dwarfs in post-common envelope binaries that emit strong cyclotron emission using the Zwicky Transient Facility (ZTF) light curves, doubling the known sample size. In addition, we discovered a candidate magnetic period bouncer and recovered three known ones. We confirmed the presence of cyclotron emission using low-resolution spectra in 19 objects. Using the ZTF light curves, follow-up spectra, and the spectral energy distribution, we measured the orbital period, magnetic field strength, and white dwarf temperature of each system. Although the phase-folded light curves have diverse shapes and show a much larger variability amplitude, we show that their intrinsic properties (e.g. period distribution, magnetic field strength) are similar to those of previously known systems. The diversity in light curve shapes can be explained by differences in the optical depth of the accretion spot and geometric differences, the inclination angle and the magnetic spot latitude. The evolutionary states of the longer period binaries are somewhat uncertain but are vary; we found systems consistent with being pre-polars, detached polars, or low-state polars. In addition, we discovered two new low-state polars that likely have brown dwarf companions and could be magnetic period bouncers
Exploring post-rehabilitation plasticity with intra-cerebral recordings on anomic profiles
No full textInternational audienceBackground: Patients with drug-resistant epilepsy involving the language network often exhibit anomic profiles in daily life due to difficulties with lexical selection processes. Very little evidence is available regarding the effects of language rehabilitation in this population. Objective(s): We aim to induce brain plasticity combined with improvements in behavioral performance using language therapy in patients with epilepsy. Methods: We implemented a therapy focused on phonological and semantic features of infrequent words over three treatment sessions, each targeting a specific semantic category. Intracranial signals were recorded in 10 patients during baseline and post-therapy picture-naming sessions. Response times and the percentages of correct responses during naming tests were collected. Time-frequency analyses were conducted on intracranial signals, and comparisons were made between baseline and post-therapy conditions for each patient. Results: Half of the patients demonstrated improved naming skills following the treatment. We observed significantly different recruitment of frontotemporal areas in the left hemisphere (including Broca's area) post-therapy in patients that improved naming skills. Specifically, we found significantly different high-gamma activity in the posterior left inferior frontal gyrus 500 ms after stimulus onset in patients with improved naming skills vs. non-improved naming skills. This effect was not observed in the right hemisphere. Conclusions: These findings suggest that enhanced performance following language therapy is associated with modifications in posterior left IFG activations during latencies closely tied to the lexical selection process