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Expanded Composite Coral Indices of South Pacific Convergence Zone Oceanographic Variability Since 1848 CE
No full textInternational audienceAbstract In the South Pacific Convergence Zone (SPCZ), interannual to interdecadal oceanic and atmospheric variability is especially pronounced. The El Niño Southern Oscillation and the Interdecadal Pacific Oscillation significantly influence the SPCZ diagonal axis and salinity front. Regional coral‐based paleo‐environmental reconstructions extend the relatively short and discontinuous instrumental sea surface temperature (SST) and sea surface salinity (SSS) record to elucidate past variability. We present monthly resolved, composite indices of coral skeletal δ 18 O, Sr/Ca, and calculated δ 18 O sw utilizing coral geochemical time‐series from Rotuma, Fiji, Tonga, and Rarotonga, dubbed the SPCZ coral (SPCZ c ) indices. The new indices build upon previous efforts to describe variability and trends in the SPCZ region with expanded coverage due to a new northwestern coral addition from the SPCZ fresh pool. The increased spatial and temporal resolution of the new indices allows for higher‐fidelity sub‐annual reconstructions of SST and SSS in the region dating back to 1848. The results confirm the secular warming trend of 1°C in the SPCZ region and show a 0.4 S p freshening starting in the 1880s. The SPCZ c δ 18 O sw is the first regional reconstruction of δ 18 O sw and provides valuable insights into past SSS variability, including elucidating responses to El Niño and La Niña events, as well as identifying past SPCZ zonal events. The SPCZ c δ 18 O sw reconstruction extends the instrumental records by ∼100 years. The SPCZ c indices prove the utility of the compositing approach in describing regional oceanographic variability with the increased signal‐to‐noise ratio of the obtained coral climatic data
L'éducation à l'alimentation pour sensibiliser au développement durable au cycle 3
No full textIn an ever-changing world, the only timeless thing that unites all living beings is life. This life exists thanks to food and the presence of liquid water on earth. However, in our modern society, it's important to understand what's at stake when it comes to food. The concept of food has developed thanks to a wealth of scientific knowledge about health and sport. What's more, access to large quantities of food has increased in developed countries. However, food production methods must be normed, responsible and sustainable, as nature feeds us and we must respect it. That's why it's so important that, from an early age, children are made aware of mankind's responsibility : to live in harmony with Mother Earth. The aim is to address the societal issues of food and sustainable development, so that we can teach tomorrow's adults about healthy living and sustainable eating.Dans un monde en constante évolution, la seule intemporalité qui unit tous les êtres vivants est la vie. Cette vie existe grâce à l’alimentation et à la présence d’eau liquide sur terre. Cependant dans notre société moderne, il est important de comprendre les enjeux qu’englobe l’alimentation. Le concept d'alimentation s’est développé grâce aux connaissances scientifiques nombreuses autour de la santé et du sport. De plus, l’accès à la nourriture en grande quantité s’est amplifié dans les pays développés. Cependant, les méthodes de production de la nourriture doivent être normées, responsables et durables en lien avec le développement durable car la nature nous nourrit et nous devons la respecter. C’est pourquoi il est important que dès leur plus jeune âge, les enfants soient sensibilisés à la responsabilité qui incombe à l'humanité : vivre en respectant sa terre mère. Ainsi, il s’agira de traiter des enjeux sociétaux que sont l’alimentation et le développement durable afin de pouvoir enseigner un mode de vie sain et une alimentation durable aux adultes de demain
Health literacy among individuals with type 2 diabetes in France: greater social inequalities among women; the Entred 3 study
No full textInternational audienceThe aim of this study was to describe and explore the health literacy in people living with type 2 diabetes in mainland France and its association with socioeconomic factors. ENTRED 3 is a nationally representative French diabetes population-based survey conducted in 2019. Health literacy was measured using two scales from the Health Literacy Questionnaire: ability to actively engage with healthcare providers (HLQ6) and sufficient understanding of health information to know what to do (HLQ9). Gender-stratified analyses and multivariate linear regressions were conducted to study health literacy according to education level and country of birth, adjusting for age and antidiabetic treatment. These analyses were weighted to account for the study's complex sampling design and non-response bias. Two thousand seven hundred fourteen people living with type 2 diabetes responded to the ENTRED 3 questionnaire. The mean scores for respectively HLQ6 and HLQ9 were significantly higher among men (4.03 (sd 0.02); 4.16 (sd 0.03)) than among women (3.87 (sd 0.01); 3.98 (sd 0.05)). At comparable age and antidiabetic treatment: i) education level were positively associated with HLQ6 and HLQ9 among men; ii) women born in North Africa had lower HLQ6 and faced more pronounced educational inequalities with regards to HLQ9 than women born in France. This study provides a reference for health literacy in persons living with type 2 diabetes in France and identifies a link between health literacy and socioeconomic factors. Its results represent a significant step in the understanding of the mechanisms of social inequalities in health in France
Responses of the Natural Phytoplankton Assemblage to Patagonian Dust Input and Anthropogenic Changes in the Southern Ocean
No full textInternational audienceAbstract The cumulative effects of multi‐faceted changes on the phytoplankton community of the Southern Ocean (SO) are not yet known, which is a major limitation to predicting the future direction of the biological carbon pump. Thus, our study aimed to estimate the effects of intensified Patagonian dust inputs, warming and acidification on the growth, composition and production of phytoplankton assemblages in the Polar Frontal Zone (PFZ) and the High‐Nutrient Low‐Chlorophyll (HNLC) region of the Indian sector of the SO during the austral summer 2022. Natural phytoplankton communities were incubated for 5‐day under 4 scenarios (present and future conditions, and 2 intermediate scenarios). In the PFZ, +3°C and acidification stimulated the growth of phytoplankton, mainly cyanobacteria, while intensified dust inputs alone did not have notable impact. Conversely, in HNLC waters, the addition of Fe‐dust alone increased the total chlorophyll a of diatoms (mainly F. kerguelensis ), whereas the negative effect of acidification and +3°C counteracted the positive impact of dust input on the diatoms. In these waters, future conditions benefited smaller species (haptophytes and cyanobacteria). The net particulate organic carbon production (POC) was also unaltered by future conditions, suggesting that primary production may not change in the future SO. However the increase in the length and number of long‐chain diatoms under future HNLC conditions may indicate that POC export could intensify in the future
Comparing Bias Correction Methods for Downscaling Daily Precipitation in Impact Studies over the Sudano Sahelian Region of Cameroon
No full textSource Agritrop Cirad (https://agritrop.cirad.fr/613544/) * Autres projets (id;sigle;titre): ;MOPGA;(FRA) Make Our Planet Great Again//International audienc
Correction: Health literacy among individuals with type 2 diabetes in France: greater social inequalities among women; the Entred 3 study
No full textInternational audienc
De l'intérêt de machines notionnelles adaptées à l'apprentissage de la programmation en Python
No full textNational audienceNous présentons deux études exploratoires montrant d'une part l'imprécision ou le caractère erroné des modèles mentaux de l'exécution d'un programme Python chez des apprenants débutants, et d'autre part la faible utilisation par les enseignants de machines notionnelles adaptées. La première étude a été réalisée auprès d'étudiants entrants en licence d'informatique. La seconde étude a été menée auprès des enseignants de spécialité NSI de l'académie. En nous référant aux travaux académiques sur les machines notionnelles et sur les outils de visualisation, nous formulons l'hypothèse que ces observations peuvent être liées. Nous postulons donc l'intérêt de définir et partager des machines notionnelles adaptées, capables d'induire des modèles mentaux conformes chez les élèves. Nous concluons avec des perspectives d'élaboration de machines notionnelles adaptées à chaque niveau d'apprentissage, à savoir un modèle d'ardoise pour les débutants - en classe de seconde et première - et un modèle de références capable de distinguer mutables et non mutables pour les programmeurs avancés - en classe de terminale ou en première année à l'université
Comparison of Machine Learning Algorithms for Daily Runoff Forecasting with Global Rainfall Products in Algeria
No full textInternational audienceRainfall–runoff models are crucial tools for managing water resources. The absence of reliable rainfall data in many regions of the world is a major limitation for these models, notably in many African countries, although some recent global rainfall products can effectively monitor rainfall from space. In Algeria, to identify a relevant modeling approach using this new source of rainfall information, the present research aims to (i) compare a conceptual model (GR4J) and seven machine learning algorithms (FFNN, ELM, LSTM, LSTM2, GRU, SVM, and GPR) and (ii) compare different types of precipitation inputs, including four satellite products (CHIRPS, SM2RAIN, GPM, and PERSIANN), one reanalysis product (ERA5), and observed precipitation, to assess which combination of models and precipitation data provides the optimal performance for river discharge simulation. The results show that the ELM, FFNN, and LSTM algorithms give the best performance (NSE > 0.6) for river runoff simulation and provide reliable alternatives compared to a conceptual hydrological model. The SM2RAIN-ASCAT and ERA5 rainfall products are as efficient as observed precipitation in this data-scarce context. Consequently, this work is the first step towards the implementation of these tools for the operational monitoring of surface water resources in Algeria
Rubidium and potassium isotope compositions of enstatite meteorites: implications for the evolution of their parent body(ies)
No full textInternational audienceEnstatite meteorites, including enstatite chondrites and enstatite achondrites (e.g., aubrites), formed under highly reducing conditions in the solar system. Enstatite chondrites underwent progressive thermal metamorphism from petrologic type 3 to type 6, potentially leading to vaporization and redistribution of volatile elements. Coupled Rb and K isotopic analyses of enstatite meteorites could provide complementary insights into the inherent isotopic variability and volatile depletion processes. In this study, we present Rb and K isotopic compositions for a suite of enstatite meteorites, including sixteen enstatite chondrites spanning metamorphic grades from 3 to 6, as well as four aubrites. Type 3 enstatite chondrites exhibit isotopic compositions similar to those of Earth for both Rb and K, which further underscores the isotopic resemblance between Earth and enstatite chondrites. From type 3–4 to type 5–6, the examined enstatite chondrites generally show a trend towards heavier Rb and K isotopic compositions, indicating volatilization and redistribution of Rb and K during open system thermal metamorphism of the parent body(ies). One EH5 (St. Marks) and two EL6 (Pillistfer and Atlanta) samples deviate from this trend with light K isotope compositions, which may result from an interplay of evaporation, vapor transport and recondensation. On the other hand, the Rb and K isotopic variations in aubrites—which originated from the melting and fractional crystallization of enstatite chondrite-like parent body(ies)—likely reflect more complex processes, possibly involving a combination of plagioclase-bearing melt extraction, magmatic differentiation, core segregation, and the back-condensation of volatiles after impact volatilization
Potassium isotopic compositions and model exposure ages of lunar soils
No full textInternational audienceSpace weathering has long been known to alter the chemical and physical properties of the surfaces of airless bodies such as the Moon. The isotopic compositions of moderately volatile elements in lunar regolith samples could serve as sensitive tracers for assessing the intensity and duration of space weathering. In this study, we develop a new quantitative tool to study space weathering and constrain surface exposure ages based on potassium isotopic compositions of lunar soils. We first report the K isotopic compositions of 13 bulk lunar soils and 20 interval soil samples from the Apollo 15 deep drill core (15004 – 15006). We observe significant K isotope fractionation in these lunar soil samples, ranging from 0.00 ‰ to + 11.77 ‰, compared to the bulk silicate Moon (–0.07 ± 0.09 ‰). Additionally, a strong correlation between soil maturity (Is/FeO) and K isotope fractionation is identified for the first time, consistent with other isotope systems of moderately volatile elements such as S, Cu, Zn, Se, Rb, and Cd. Subsequently, we conduct numerical modeling to better constrain the processes of volatile element depletion and isotope fractionation on the Moon and calculate a new K Isotope Model Exposure Age (KIMEA) through this model. We demonstrate that this KIMEA is most sensitive to samples with an exposure age lower than 1,000 Ma and becomes less effective for older samples. This novel K isotope tool can be utilized to evaluate the surface exposure ages of regolith samples on the Moon and potentially on other airless bodies if calibrated using other methods (e.g., cosmogenic noble gases) or experimental data