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Placental crises: disruptive selection and maternal under‐investment as the foundations of mammalian placental evolution and dysfunction
No full textInternational audienceAmong the vertebrates, mammals are notable for the dominance of live birth and placental nutrition. The structural diversity of the mammalian placenta is remarkable, despite sharing a single common ancestor and conserved physiological functions. Historically, investigations into the evolution of the mammalian placenta have been grounded in 'the efficiency paradigm', i.e. the assumption that certain placental configurations permit easier nutrient exchange, but this paradigm has struggled to explain the diversity of mammalian placentation strategies. Here, we propose a new paradigm to understand mammalian placental evolution. Using multidimensional plotting of recorded placental structures, quantitative metrics for mammalian maternal investment, and illustrative computational modelling of physiological processes, we argue that the ancestral mammalian placenta is not a streamlined 'highly efficient' design, but rather a product of low maternal investment, with fitness costs that manifest as gestational demand increases. Expansion of small mammals into larger-bodied, longer-lived niches induces a 'placental crisis' characterised by maternal under-investment and chronic gestational dysfunction, triggering an arms race through the interaction of disruptive selection and materno-fetal conflict. We propose the acute severity of the placental crisis is the foundation of placental evolution. We go on to argue that some primates are currently in a state of placental crisis and that maternal under-investment and inappropriate placentation are the evolutionary foundations of human gestational dysfunctions such as pre-eclampsia. We conclude that the ancestral mammalian placenta was not an efficiently optimised design that allowed placentation to dominate the clade, but rather an idiosyncrasy of mammal-specific biology, which likely hindered mammalian expansion into larger-bodied niches
Exciton radiative lifetimes in hexagonal diamond Ge and SiGe alloys
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La ronde paysagère, études des usages touristiques à l’œuvre dans les cas des tables d’orientation du Touring-club de France (1903-1935)
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Why methane surged in the atmosphere during the early 2020s
No full textInternational audienceThe atmospheric methane (CH 4 ) growth rate surged after 2019, peaking at 16.2 parts per billion per year (ppb year −1 ) in 2020 before declining to 8.6 ppb year −1 in 2023. Using multiple atmospheric inversions constrained by observation- and model-based prescribed hydroxyl radical (OH) fields and CH 4 atmospheric data, we show that a drop of OH radicals in 2020–2021, followed by recovery in 2022–2023, accounted for 83% of year-on-year variations in the CH 4 growth rate, the rest being explained by wetland and inland water emissions, which increased between 2019 and 2020–2022 [+8.6 ± 2.6 teragrams of CH 4 per year (TgCH 4 year −1 )] and then decreased between 2022 and 2023 (−9.9 ± 3.3 TgCH 4 year −1 ). Most emission changes from 2019 to 2023 occurred in northern tropical wetlands in Africa and Asia, whereas South American wetlands emissions declined and Arctic emissions increased after 2019
Transcultural validation in Soninke of a language assessment tool: The Avicenne ELAL©
No full textInternational audienceChildren of migrants are often exposed to more than one language from an early age. The Avicenne ELAL © test has been created to better assess language skills, avoid misdiagnosing learning disabilities, and inform early interventions. Plurilingual children aged 3.5 to 6.5 take the test in their mother tongues, with an interpreter's assistance. The test comprises three scales: Comprehension, Expression, and Storytelling. The objectives of this study were to describe steps of the transcultural validation of the Avicenne ELAL © for the Soninke culture and language, both for children living in a monolingual environment in Mauritania and for migrant children living in a multilingual environment in France; to compare the performance of these two groups; and to explore its qualitative use in studying language pathways among bilingual and plurilingual children. A total of 71 children participated in this study in Mauritania ( n = 25) and France ( n = 46). The Avicenne ELAL ©, a 30-minute plurilingual language assessment using objects, picture boards, and storytelling tasks, was administered in Soninke (and in French for children in France) to migrant children in France and to children in Mauritania, with standardized procedures to minimize distractions and ensure comfort. All sessions were recorded, de-identified, and supplemented with field notes and a logbook to capture contextual and qualitative elements of children's language use. The results of the two groups of children were analyzed and compared with quantitative and qualitative methods. Given the excellent results of the monolingual children, the ELAL in the Soninke language can be considered valid. Statistical analysis confirmed significant differences between the children's scores in Mauritania and France, for both the total score and each separate scale (Comprehension, Expression, and Storytelling). The results also showed that the quality of the narrative skills (storytelling) was strongly correlated with the child's age. Comparing the language assessments collected in these two settings highlights the variations and cultural specificities that should be considered when studying the language skills of Soninke-speaking migrant children
Small persistent humid forest clearings drive tropical forest biomass losses
No full textInternational audienceTropical forests store about half of the global forest aboveground carbon (AGC)1, yet extensive areas are affected by disturbances, such as deforestation from agricultural expansion2,3 and degradation from fires4, selective logging5, and edge effects6,7. Over time, disturbed forests can recover, gradually restoring carbon stocks and ecological functions8. However, how recovery rates vary with disturbance size, type and location remains poorly quantified. Here we use a bookkeeping approach with spatially explicit vegetation recovery curves to quantify AGC dynamics in disturbed tropical forests during 1990–2020. We find that disturbed tropical dry forests remained carbon neutral, whereas disturbed tropical humid forests experienced a net AGC loss of 15.6 ± 3.7 PgC, primarily driven by small but persistent deforestation clearings. Despite affecting only about 5% of the disturbed area, these small-size (less than 2 ha) deforestation events accounted for about 56% of carbon losses, owing to persistent land-use conversion without forest regrowth. By contrast, large fire-induced carbon losses were offset by the long-term post-fire recovery. Over time, deforestation expanded into humid forests with higher carbon stock density, intensifying AGC losses per unit area. These findings highlight the disproportionate impact of small clearings on tropical carbon losses, suggesting the need to curb land-use changes and protect young and recovering forests
Atherectomy-assisted treatment or balloon angioplasty for atherosclerotic common femoral artery disease?
No full textInternational audienceBackground: To compare atherectomy-assisted endovascular revascularization with balloon angioplasty for the treatment of common femoral artery disease (CFAD). Materials and methods: In a multi-centre retrospective research collaborative, data from consecutive patients who underwent endovascular revascularization of the groin were analysed. Primary endpoints were clinically driven target-lesion-revascularization (CD-TLR) and improvement of clinical symptoms by Rutherford categories (RC). Kaplan-Mayer analyses were used to evaluate these endpoints over time in patients undergoing atherectomy-assisted versus conventional endovascular treatment. In addition, retrospective case-control matching was performed, considering patient and lesion specific characteristics. Lesion calcification was assessed using the PACSS scoring system. Results: Of 225 patients, 179 (79.6%) underwent atherectomy-assisted treatment, whereas 46 (20.4%) underwent balloon angioplasty. Mean age was 72.0 (66.0–79.0) yrs, 139 patients (61.8%) had intermittent claudication and 84 (37.3%) had chronic limb-threatening ischemia (CLTI). Involvement of the deep femoral artery femoral was present in 137 (60.9%) cases, whereas lesion calcification was moderate to severe (PACSS 2–4) in most cases (88%). Atherectomy had low complication rates (perforation in one (0.6%) patient and distal embolization requiring re-intervention in 2 (0.9%) patients) and lower rates of bail-out stenting compared to angioplasty (5.1% versus 36.7%, p<.0001). No perforation or distal embolization was observed in the angioplasty group. After matching for patient and lesion characteristics CD-TLR (HR=4.0, 95%CI=1.0–15.0, p<.05) and RC improvement rates both favoured atherectomy (93.5% versus 73.1%, p<.05). Conclusions: Atherectomy-assisted endovascular revascularization of CFAD seems to be associated with lower stent placement and re-intervention rates compared to balloon angioplasty. Future prospective trials with longer follow-up duration are now warranted
The Impact of Inclusive Education Practices on Students With ASD 'S Outcomes: Report From the ELENA French Cohort Study
No full textInternational audienceInclusive education is largely promoted in the field of autism spectrum disorders (ASD), but scientific and empiric studies about the impact of school inclusion on the children's outcome are lacking. We studied the effect of the type of inclusion (regular classroom vs. special education classroom) in a sample of 356 children with ASD over a three‐years period. Results first showed that, when comparing both groups at baseline, children in special education classes were older, had a higher level of challenging behaviors and came from lower socioeconomic status families. Once matched through propensity score, children in special classrooms had significantly lower communication and daily living skills than children in ordinary classrooms after 3 years, whereas there was no significant difference in socialization skills and in IQ. Overall, placement in a regular education classroom was positive for most children, however there is a high inter‐individual variability and it is very unlikely that inclusive settings are by default superior for all children with special needs. These results, emphasizing the crucial role of the mainstream milieu, cannot be considered definitive and further studies are needed to address this critical educational policy issue