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The GECKOS Survey : resolved, multiphase observations of mass loading and gas density in the galactic wind of NGC 4666
No full textInternational audienceWe present a multiphase, resolved study of the galactic wind extending from the nearby starburst galaxy NGC 4666. For this, we use VLT/MUSE observations from the GECKOS program and H i data from the WALLABY survey. We identify both ionized and H i gas in a biconical structure extending to at least 8 kpc from the galaxy disc, with increasing velocity offsets above the mid-plane in both phases, consistent with a multiphase wind. The measured electron density, using [S ii], differs significantly from standard expectations of galactic winds. We find electron density declines from the galaxy centre to kpc, then rises again, remaining high ( cm) out to 5 kpc. We find that H i dominates the mass loading. The total H i mass outflow rate (above z~>2 kpc) is between , accounting for uncertainties from disc-blurring and group interactions. The total ionized mass outflow rate (traced by H) is between 0.5 and , depending on assumptions. From ALMA/ACA observations, we place an upper limit on CO flux in the outflow which correlates to . We also show that the entire outflow is not limited to the bicone, but a secondary starburst at the edge generates a more widespread outflow, which should be included in simulations. The cool gas in NGC 4666 wind has insufficient velocity to escape the halo of a galaxy of its mass, especially because most of the mass is present in the slower atomic phase. This strong biconical wind contributes to gas cycling around the galaxy
Quantifying the effects of antibiotic resistance and within-host competition on strain fitness in Streptococcus pneumoniae
No full textInternational audienceCompetition plays a key role in shaping the structure and diversity of bacterial populations. In many clinically important bacterial species, strains compete at multiple scales: at the between-host scale for new hosts to colonise, and at the within-host scale during co-colonisation. Characterising these multiple facets of competition plays an important role in understanding bacterial ecology. This is particularly relevant for antibiotic resistance, where competition between antibiotic-susceptible and resistant strains determines resistance dynamics. In this work, we perform survival analyses on a large longitudinal dataset of Streptococcus pneumoniae carriage to quantify how within-host competition affects the rates of clearance and establishment of pneumococcal strains. We find that the presence of a within-host competitor is associated with a 33% increase in clearance and a 54% reduction in establishment. Priority effects and serotype differences partially predict the outcomes of this within-host competition. Further, we quantify the effects of antibiotic resistance on between- and within-host components of fitness. Antibiotic consumption is associated with increased clearance rate for both susceptible and resistant strains, albeit to a higher extent in susceptible strains. In the absence of antibiotics, we find some evidence that resistance is associated with increased susceptibility to within-host competition, suggesting a fitness cost of resistance. Overall, our work provides quantitative insights into pneumococcal competition across scales and the role of this competition in shaping pneumococcal epidemiology
Vaccine effectiveness dynamics against influenza and SARS-CoV-2 in community-tested patients in France 2023–2024
No full textInternational audienceThe epidemiology of respiratory viruses and vaccine effectiveness (VE) in the community are not well described. This study assessed VE against a positive test of influenza (VEf) and SARS-CoV-2 (VECov). Data from networks of community-based laboratories in France were collected during standard of care in the 2023-2024 epidemic season (n = 511,083 multiplex RT-PCR tests). Patients' demographics and symptoms were reported in addition to viral sequencing results. The test-negative design was used to estimate VEf and VECov by time since vaccination and calendar week. Adjusted VEf by age, sex, presence of symptoms, PCR technique, and week of testing, was 47.6% (95% CI: 44.3-50.7%). VEf was lower in patients ≥65 years (42.0%; 95% CI: 36.6-46.9%) than in 18-64 years (52.9%; 95% CI: 48.6-56.8%). The adjusted VEf against type A influenza, which represented 98% of typed viruses, was 51% (45%-56.6%) for patients vaccinated 15 days to 3 months before testing, and 35.5% (24.2%-45.3%) for those vaccinated 3-6 months before testing. For VECov, the adjusted estimate in patients vaccinated 15 days to 3 months prior to testing was 40.6% (7.2%-58.6%) at week 39, 24.8% (4.0%-38.8%) at week 45, and dropped systematically through the epidemic season as the JN.1 variant became dominant. This study showed moderate VEf and VECov against infection in the community and highlighted the impact of time since vaccination and age for both estimates, and the new variant emergence on VECov. These findings should be considered in future vaccination campaigns
Behavior and fate of ITER-like tungsten nanoparticles in freshwater ecosystems produced during operation and maintenance
No full textInternational audienceWithin the ITER project (International Thermonuclear Experimental Reactor) an international project building a magnetic confinement device to achieve fusion as a sustainable energy source, tungsten (W) is planned to serve as a plasma-facing component (PFC) in the tokamak, a magnetic confinement device used to produce controlled thermonuclear fusion power. Post plasma-W interactions, submicron tungsten particles can be released. This study investigated the exposure of lentic freshwater ecosystems to ITER-like tungsten nanoparticles in indoor aquatic mesocosms. Monitoring included tungsten (bio)distribution, (bio)transformation, speciation, and impacts following a relevant exposure scenario (chronic, medium-term, low-dose contamination). Additionally, mechanistic studies using a combination of microfluidic cells and X-ray Absorption Spectroscopy (XAS) provided a time-resolved understanding of tungsten's oxidative dissolution in freshwater. Following contamination, tungsten persisted in the water column (over 90%), showing significant (~40%) and rapid (7 days) oxidation-dissolution and polymerization. This led to significant exposure of planktonic niches, strong affinity of polymeric tungsten species for aquatic vegetation, and potential transfer to higher trophic levels like aquatic snails. Over five weeks, the bio-physicochemical parameters of the mesocosms remained stable, and no acute impacts were observed on micro- and macro-organisms
Боспор Киммерийский и северные варвары в постгуннское время: экспорт престижной культуры
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Combining population genomics with ancient DNA to understand island colonization history of the Madagascar turtle dove
No full textAbstract The Mascarene archipelago (Mauritius, Reunion and Rodrigues), characterized by first human arrival being recent, offers a unique setting to study species colonization. Here we use a combination of modern and ancient DNA data as a case study to investigate the recent colonization history of a species of concern in relation to conservation programs – the Madagascar turtle dove ( Nesoenas picturata ) on Mauritius and Reunion. We generated a reference genome and re-sequenced genomes from contemporary N. picturata populations, as well as genome-wide data from relevant subfossils. A combination of model-free inferences, site frequency spectrum (SFS) based demographic modelling, and analyses of population structure including that of subfossils indicate that N. picturata colonized both islands independently and naturally from Madagascar, long before human arrival. Summary statistics and SFS-based modeling reveal large effective population sizes ( Ne ) and high genetic diversity in island populations, conflicting with historical accounts of human-induced demographic collapse. Based on goodness-of-fit, genetic structure and diversity indices do not discriminate between two solutions, one of which posits large recent Ne and negligible translocation rates, while the other supports recent severe bottlenecks followed by high post-human translocation from Madagascar. Nonetheless, linkage disequilibrium provides stronger evidence for the latter scenario, which may also explain high genetic diversity. Both modern and ancient DNA data sources independently support the classification of N. picturata as native to both islands. Our findings highlight the importance of validating demographic models with multiple summary statistics, and potential of using a combination of different data sources to resolve colonization history in recent time
Alkynyl Radicals, Myths and Realities
No full textInternational audienceThis Perspective deals with the organic chemistry of alkynyl radicals, a species that is ultimately still little known in the synthetic community. Starting with the first observations and characterizations of alkynyl radicals generated by various methodologies in the gas phase, we then particularly turned our attention to the implications of these highly reactive intermediates in organic synthesis and materials science. Mechanistic considerations have been provided, in particular, for the key steps of generating alkynyl radicals, which are mainly based on photochemical or thermal activation and single electron transfer processes. This Perspective should serve as a roadmap for the synthetic chemist in order to plan more reliably alkynylation reactions based on alkynyl radicals
Origin of gas in the Magellanic Bridge: MeerKAT detection of H I 21 cm absorption
No full textInternational audienceAims. H I 21 cm absorption lines are investigated to determine the origin of the neutral atomic hydrogen (H I ) of the Magellanic Bridge (MB). Using MeerKat Absorption Line Survey (MALS) data, we report the detection of an H I absorption line at a peak signal-to-noise ratio (S/N) of 10 caused by MB gas observed against the radio source J033242.97-724904.5. In combination with earlier data obtained with the Australia Telescope Compact Array (ATCA), our new detected H I line enables the exploration of the MB atomic hydrogen gas across 4–6 kpc. Methods. We investigated the radial velocity profiles from the ATCA data and included new data from MALS in the analysis. Apart from the excitation conditions, we considered the radial velocity structure of the H I gas seen in emission and absorption. The gas-to-dust ratio was quantified to help identify whether the MB gas had originated from the SMC (Small Magellanic Cloud) or the LMC (Large Magellanic Cloud). Results. The H I absorption lines toward lines of sight separated by a few kiloparsecs consistently coincide with the densest and possibly the coolest gas at the lower radial-velocity limit of the corresponding H I emission profiles. The gas-to-dust ratio was found to be consistent with the MB gas originating in the LMC. The large-scale velocity distribution, as seen from the H I absorption features, favors the LMC-SMC direct collision scenario over the close fly-by scenario, which is also supported by results from recent numerical simulations
Abnormal Connectivity of the Head Neural Integrator in Cervical Dystonia
No full textInternational audienceBackground Cervical dystonia is characterized by abnormal neck and head movements, possibly related to a dysfunction of the interstitial nucleus of Cajal (INC) and the head neural integrator, a system responsible for the control of head and eye movements. However, neuroanatomical evidence of alterations in the head neural integrator in cervical dystonia is sparse. Objectives We investigated structural and functional integrity of the INC and its connections in cervical dystonia. Methods This cross‐sectional, observational study compared 19 cervical dystonia patients and 21 healthy controls, using anatomical, diffusion‐weighted, and resting‐state functional images. We reconstructed tracts converging on the INC, and involved in the control of head movements. We evaluated group differences in microstructural integrity using fixel‐based analysis, and effective connectivity using dynamic causal modeling. Results Compared with controls, patients showed microstructural abnormalities within the INC and cerebral peduncle. Effective connectivity showed abnormal self‐inhibition in the INC, substantia nigra, and vermis in patients, with decreased excitation from the substantia nigra to the INC, increased inhibition from the deep cerebellar nuclei and primary sensorimotor cortex, and decreased excitation from the INC to the cerebellar vermis. Conclusions A dysfunction of the INC might contribute to altered sensorimotor integration in cervical dystonia, and abnormal feedback from its afferent connections could alter its integrative function, resulting in a disturbed head and neck posture. © 2025 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society
Densification-Related Optical and Photodetection Properties of Green-Synthesized MAPbI<sub>3</sub> and MAPbI<sub>3</sub>@Graphite Powders
No full textInternational audienceFor photodetection applications using 3D hybrid perovskites (HPs), dense and thick films or compacted powders in wafer form are needed and generally require large amounts of HPs. HPs are also often combined with a graphene/carbon layer to improve their conductivity. Among HP synthesis methods, mechanosynthesis, a green synthesis method, provides a large amount of powders, which are furthermore easily densified in compact wafers due to their mechanical activation. Thus, methylammonium lead iodide (MAPI) and MAPI with 3 and 5 wt % graphite powders were synthesized, densified by uniaxial compaction, and their photoluminescent (PL) and photodetection properties were studied. MAPI wafers compacted under 100 and 500 MPa showed a PL blue shift compared to the MAPI powder, and photodetection measurements indicated that composite wafers exhibited an enhanced photoresponse with improved photocurrent generation due to the addition of graphite. However, they exhibited weaker photoswitching (on/off) sensitivity with high detected currents in comparison to the MAPI wafer. Such unexpected photodetection behavior with composite wafers were explained by characterizing their microstructural and optical properties. Microstructural characterizations showed no grain coalescence in all MAPI and composite wafers compacted at 100 MPa, but a preferential crystallographic orientation along the {002} plane was detected. Additionally, an unusual graphite segregation near the wafer surface was noticed in composite wafers, questioning the effect of graphite in photodetection performance. Furthermore, all optical measurements evidenced lattice distortions and a decrease of the PL reabsorption phenomenon as a function of the densification pressure, in agreement with the observation of a higher population of photoexcited charge carriers in MAPI compacted at 500 MPa, as observed in transient absorption spectroscopy. These findings demonstrate that green-synthesized MAPI and graphite composites can be easily shaped into dense wafers through simple low-pressure compaction and emphasize the importance of microstructural and optical characterizations to fully understand the resulting properties