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Proposant des ouvrages de cours de référence, la collection ECNi - LES REFERENTIELS tient compte de l’évolution des enseignements et des besoins des étudiants qui préparent les ECNi. Ses auteurs – tous professeurs universitaires - s’attachent à fournir au lecteur un outil complet de révisions, conforme au programme du concours. Dans cet ouvrage, le programme de la spécialité Orthopédie-Traumatologie est traité de façon complète, avec : Un cours de référence en accord avec les conférences de consensus ; Des tableaux, des encadrés et de l'iconographie en couleur pour y voir plus clair ; L’essentiel à retenir. Cet ouvrage très explicatif facilite l’apprentissage des notions en privilégiant leur compréhension, afin de réussir les ECNi.

Véritable mine d'informations concrètes et rassurantes, ce livre est le résultat du travail d'experts du Collège national des gynécologues et obstétriciens français (CNGOF). Ils ont compilé leur savoir pour le rendre accessible à toutes et vous permettre de vivre pleinement la merveilleuse aventure de votre grossesse. Les spécialistes du domaine (gynécologues, sages-femmes, pédiatres, pédopsychiatres, acupuncteurs, homéopathes...) répondent avec bienveillance à toutes les questions que vous vous posez pour vous aider à : comprendre tous les mécanismes de votre grossesse, du désir d'enfant à la fécondation ; suivre votre grossesse, mois par mois, semaine après semaine ; décrypter ce que le médecin voit et recherche à l'échographie ; connaître les traitements possibles contre les petits maux ; préparer votre accouchement ; anticiper votre retour à la maison avec bébé ; effectuer toutes les démarches administratives... Un guide ultra complet : près de 500 pages, 140 schémas explicatifs, 45 échographies décryptées et de nombreuses vidéos gratuites pour suivre mois par mois l'évolution de votre grossesse et préparer l'arrivée de bébé.

La notion de représentation linguistique (RL) intéresse aujourd’hui toutes les disciplines « sociocompatibles », pour reprendre l’expression du professeur Laurent Gajo — et la didactique des langues ne fait pas exception. La recherche a montré depuis longtemps que les représentations entretiennent un lien complexe et ambivalent avec les processus d’apprentissage, qu’elles contribuent à fortifier ou à ralentir. Ainsi, en ce qui concerne les langues, la perception de leur utilité, facilité, esthétique ou encore du capital sympathie des locuteurs encourage ou décourage le choix de les apprendre. Une fois le choix effectué ou imposé, les RL des apprenants guideront leur apprentissage et leur utilisation de la langue en question. En fait, leurs RL seront même déterminantes pour la réussite ou pour l’échec du processus d’acquisition. Elles constituent donc un enjeu de taille en didactique des langues-cultures, dès lors que leur étude permet, d’une part, de comprendre des dynamiques à l’œuvre durant l’utilisation et l’enseignement-apprentissage des langues, et, d’autre part, de mettre en place des stratégies didactiques appropriées.Cette contribution vise à introduire les enjeux de l’étude des représentations linguistiques (RL) dans le cadre de la didactique du français langue étrangère. Nous présenterons brièvement les aspects théoriques de cette notion extrêmement riche. À l’aide d’exemples concrets, nous explorerons le potentiel de l’étude des RL, autant pour le chercheur en didactique que pour l’enseignant de FLE., info:eu-repo/semantics/nonPublished

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Climate change is currently impacting and threatening the entire biosphere, especially coastal marine ecosystems (Harley et al., 2006). In particular, climate change has been identified as a major driver of loss in coastal marine biodiversity and ecosystem functioning linked to the increase in the frequency and the intensity of marine heatwaves (MHWs)—anomalously prolonged periods of warm ocean temperatures or extremely warm temperature during short periods (Smith et al., 2023). The Mediterranean Sea has particularly experienced widespread mass mortality events (MMEs) driven by MHWs across the basin over the last two decades (Garrabou et al., 2022). During summer 2022, the NW Mediterranean was affected by one of the strongest MME ever recorded in the region affecting several species including gorgonians, sponges, bryozoans, bivalve molluscs, and calcareous algae. As in previous MMEs, mortality in these species resulted in the development of tissue necrosis affecting part of or the entirety of colonies (Figure 1a). In the Calanques National Park, France, two of its most emblematic species, the red gorgonian (Paramuricea clavata) and the red coral (Corallium rubrum), were dramatically affected. [...]

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Mercury is a pollutant of global concern, especially in the Arctic, where high levels are found in biota despite its remote location. Mercury is transported to the Arctic via atmospheric, oceanic and riverine long-range pathways, where it accumulates in aquatic and terrestrial ecosystems. While present-day mercury deposition in the Arctic from natural and anthropogenic emissions is extensively studied, the control of past climate changes on natural mercury variability remains unknown. Here we present an Arctic mercury record covering the Last Glacial Termination to the early Holocene epoch (15.7–9.0 thousand years before 2000 ce), collected as part of the East Greenland Ice-Core Project. We find a threefold increase in mercury depositional fluxes from the Last Glacial Termination into the early Holocene, which coincided with abrupt regional climate warming. Atmospheric chemistry modelling, combined with available sea-ice proxies, indicates that oceanic mercury evaporation and atmospheric bromine drove the increase in mercury flux during this climatic transition. Our results suggest that environmental changes associated with climate warming may contribute to increasing mercury levels in Arctic ecosystems.

The Arctic experiences a rapid retreat of sea-ice, particularly in spring and summer, which may dramatically affect pagophilic species. In recent years, the decline of many Arctic seabird populations has raised concerns about the potential role of sea-ice habitats on their demography. Spring sea-ice drives the dynamics of phytoplankton blooms, the basis of Arctic food webs, and changes in spring sea-ice have the potential to affect the demographic parameters of seabirds through bottom-up processes. To better understand the effects of spring sea-ice on Arctic seabirds, we investigated the influence of spring sea-ice concentration on the survival and breeding success of three seabird species with contrasted foraging strategies in two Svalbard fjords in the high Arctic. We examined these relationships using long-term demographic data (2005–2021) from black-legged kittiwakes (Rissa tridactyla), Brünnich guillemots (Uria lomvia), and little auks (Alle alle). Spring sea-ice concentration was positively related to both the survival and breeding success of little auks, suggesting a higher sensitivity of this species to spring sea-ice. By contrast, the two other species were not particularly sensitive to changes in spring sea-ice, even though a potentially spurious negative effect on the breeding success of black-legged kittiwakes was observed. Overall, the study suggests that spring sea-ice may be involved in the demography of Arctic seabirds, but probably does not play a major role

Phytoplankton account for >45% of global primary production, and have an enor-mous impact on aquatic food webs and on the entire Earth System. Their members are found among prokaryotes (cyanobacteria) and multiple eukaryotic lineages con-taining chloroplasts. Genetic surveys of phytoplankton communities generally consist of PCR amplification of bacterial (16S), nuclear (18S) and/or chloroplastic (16S) rRNA marker genes from DNA extracted from environmental samples. However, our appre-ciation of phytoplankton abundance or biomass is limited by PCR-amplification biases, rRNA gene copy number variations across taxa, and the fact that rRNA genes do not provide insights into metabolic traits such as photosynthesis. Here, we targeted the photosynthetic gene psbO from metagenomes to circumvent these limitations: the method is PCR-free, and the gene is universally and exclusively present in photosyn-thetic prokaryotes and eukaryotes, mainly in one copy per genome. We applied and validated this new strategy with the size-fractionated marine samples collected by Tara Oceans, and showed improved correlations with flow cytometry and microscopy than when based on rRNA genes. Furthermore, we revealed unexpected features of the ecology of these ecosystems, such as the high abundance of picocyanobacterial aggregates and symbionts in the ocean, and the decrease in relative abundance of phototrophs towards the larger size classes of marine dinoflagellates. To facilitate the incorporation of psbO in molecular- based surveys, we compiled a curated database of >18,000 unique sequences. Overall, psbO appears to be a promising new gene marker for molecular- based evaluations of entire phytoplankton communities

[EN] Nahal Efe is the largest and best preserved Middle PPNB site in the Negev (Israel), constituting a privileged data source for reconstructing the animal exploitation and subsistence strategies of the hunter-gatherer communities that inhabited the Negev 10,000 years ago. The preliminary results of the study of the faunal assemblage from excavation seasons 2015–2019 are presented in this paper. The zooarchaeological study indicates that during the Middle PPNB the community of hunter-gatherers at Nahal Efe exploited a wide spectrum of animal species, favoured by the great potential in terms of animal resources that the site’s surroundings offered, in a contact area between different eco-zones. Large and middle-sized ungulates, small carnivores, hares, and birds were captured, revealing the variability and adaptability of the hunting strategies of the community at Nahal Efe. Hunting, as a source of animal-based food, focused on the exploitation of ibex (C. nubiana) and gazelle (G. gazella) in similar proportions, which were most probably transported complete or almost complete to the site and intensively processed. Finally, another remarkable aspect of the faunal assemblage is the deposit of remains of at least three species of diurnal raptors inside a pit in one of the excavated residential buildings (Unit 10), evidencing the exploitation of birds of prey, most probably to acquire raw materials (e.g. feathers and talons). The presence of fox remains at the site also seems to be related to the procurement of raw materials, furs in this case, but its consumption is also suspected., [FR] Nahal Efe est le plus grand et le mieux préservé des sites du PPNB moyen du Néguev (Israël), constituant une source de données privilégiée pour reconstruire les stratégies d’exploitation animale et de subsistance des communautés de chasseurs-cueilleurs habitant le Néguev il y a 10 000 ans. Les résultats préliminaires de l’étude de l’assemblage faunique des saisons de fouilles 2015-2019 sont présentés dans cet article. L’étude zooarchéologique indique qu’au cours du PPNB moyen, la communauté de chasseurscueilleurs de Nahal Efe a exploité un large spectre d’espèces animales, favorisé par le grand potentiel en termes de ressources animales qu’offrait l’environnement du site, dans une zone de contact entre différentes écozones. Des ongulés de grande et moyenne taille, des petits carnivores, des lièvres et des oiseaux ont été capturés, révélant la variabilité et l’adaptabilité des stratégies de chasse de la communauté de Nahal Efe. La chasse, en tant que source d’aliments d’origine animale, s’est concentrée sur l’exploitation du bouquetin (C. nubiana) et de la gazelle (G. gazella) dans des proportions similaires, qui ont très probablement été transportés complets ou presque complets sur le site et transformés de manière intensive. Par ailleurs, un autre aspect remarquable de l’assemblage faunique est le dépôt de restes d’au moins trois espèces de rapaces diurnes à l’intérieur d’une fosse dans l’un des bâtiments résidentiels fouillés (unité 10), ce qui témoigne de l’exploitation des oiseaux de proie, très probablement pour acquérir des matières premières (par exemple des plumes et des serres). La présence de restes de renards sur le site semble également liée à l’acquisition de matières premières, en l’occurrence des fourrures, mais sa consommation est également suspectée.

For decades, marine plankton have been investigated for their capacity to modulate biogeochemical cycles and provide fishery resources. Between the sunlit (epipelagic) layer and the deep dark waters, lies a vast and heterogeneous part of the ocean: the mesopelagic zone. How plankton composition is shaped by environment has been well-explored in the epipelagic but much less in the mesopelagic ocean. Here, we conducted comparative analyses of trans-kingdom community assemblages thriving in the mesopelagic oxygen minimum zone (OMZ), mesopelagic oxic, and their epipelagic counterparts. We identified nine distinct types of intermediate water masses that correlate with variation in mesopelagic community composition. Furthermore, oxygen, NO3− and particle flux together appeared as the main drivers governing these communities. Novel taxonomic signatures emerged from OMZ while a global co-occurrence network analysis showed that about 70% of the abundance of mesopelagic plankton groups is organized into three community modules. One module gathers prokaryotes, pico-eukaryotes and Nucleo-Cytoplasmic Large DNA Viruses (NCLDV) from oxic regions, and the two other modules are enriched in OMZ prokaryotes and OMZ pico-eukaryotes, respectively. We hypothesize that OMZ conditions led to a diversification of ecological niches, and thus communities, due to selective pressure from limited resources. Our study further clarifies the interplay between environmental factors in the mesopelagic oxic and OMZ, and the compositional features of communities

The ACCOBAMS Survey Initiative (ASI) is the first synoptic large-scale survey of the entire ACCOBAMS Area and as such it plays a key role in filling the current gaps in our biological and ecological knowledge of large vertebrate species occurring in the region. Data gathered during the ASI were analyzed in a distance sampling surface-modelling framework to assess the summer distribution, densities and patterns, as well as to investigate the correlates of these parameters, for large vertebrate species and taxa in the Mediterranean Basin. Static and dynamic explanatory variables, including water depth (m), distance to depth contours (km), distance to canyons and seabed slope (km), sea surface temperature (°C), mixed layer depth (m) and levels of chlorophyll-a (mg/l), were considered to predict density and compute its variance spatially at a resolution of 10x10 km. A strong longitudinal gradient from low densities in the east to high densities in the west is shared by most taxa. In addition, several taxa also showed a less marked latitudinal gradient varying in direction according to species, and finally, a few of them exhibited patchy distributions.

Expanding shrubs in the Arctic trap blowing snow, increasing snow height and accelerating permafrost warming. Topography also affects snow height as snow accumulates in hollows. The respective roles of topography and erect vegetation in snow accumulation were investigated using a UAV-borne lidar at two nearby contrasted sites in northern Quebec, Canada. The North site featured tall vegetation up to 2.5 m high, moderate snow height, and smooth topography. The South site featured lower vegetation, greater snow height, and rougher topography. There was little correlation between topography and vegetation height at both sites. Vegetation lower than snow height had very little effect on snow height. When vegetation protruded above the snow, snow height was well correlated with vegetation height. The topographic position index (TPI) was well correlated with snow height when it was not masked by the effect of protruding vegetation. The North site with taller vegetation therefore showed a good correlation between vegetation height and snow height, R2 = 0.37, versus R2 = 0.04 at the South site. Regarding topography, the reverse was observed between TPI and snow height, with R2 = 0.29 at the North site and R2 = 0.67 at the South site. The combination of vegetation height and TPI improved the prediction of snow height at the North site (R2 = 0.59) but not at the South site because vegetation height has little influence there. Vegetation was therefore the main factor determining snow height when it protruded above the snow. When it did not protrude, snow height was mostly determined by topography., [Significance Statement] Wind-induced snow drifting is a major snow redistribution process in the Arctic. Shrubs trap drifting snow, and drifting snow accumulates in hollows. Determining the respective roles of both these processes in snow accumulation is required to predict permafrost temperature and its emission of greenhouse gases, because thicker snow limits permafrost winter cooling. Using a UAV-borne lidar, we have determined snow height distribution over two contrasted sites in the Canadian low Arctic, with varied vegetation height and topography. When snow height exceeds vegetation height, topography is a good predictor of snow height, with negligible effect of buried vegetation. When vegetation protrudes above the snow, combining both topography and vegetation height is required for a good prediction of snow height.

During the East Antarctic International Ice Sheet Traverse (Eaiist, december 2019), in an unexplored part of the East Antarctic Plateau, snow samples were collected to expand our knowledge of the latitudinal variability of iodine, bromine and sodium as well as their relation in connection with emission processes and photochemical activation in this unexplored area. A total of 32 surface (0-5 cm) and 32 bulk (average of 1 m depth) samples were taken and analysed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Our results show that there is no relevant latitudinal trend for bromine and sodium. For bromine they also show that it has no significant post-depositional mechanisms while its inland surface snow concentration is influenced by spring coastal bromine explosions. Iodine concentrations are several orders of magnitude lower than bromine and sodium and they show a decreasing trend in the surface samples concentration moving southward. This suggests that other processes affect its accumulation in surface snow, probably related to the radial reduction in the ozone layer moving towards central Antarctica. Even though all iodine, bromine and sodium present similar long-range transport from the dominant coastal Antarctic sources, the annual seasonal cycle of the ozone hole over Antarctica increases the amount of UV radiation (in the 280-320 nm range) reaching the surface, thereby affecting the surface snow photoactivation of iodine. A comparison between the bulk and surface samples supports the conclusion that iodine undergoes spring and summer snow recycling that increases its atmospheric lifetime, while it tends to accumulate during the winter months when photochemistry ceases.

Climate change poses a significant threat to coastal areas, marked by the increasing intensity and frequency of marine heat waves observed in various ecosystems around the world. Over the last 25 years, a vast number of Mediterranean populations of the red gorgonian Paramuricea clavata have been impacted by marine heatwaves. The last mass mortality occurred during the summer of 2022 in the Western Mediterranean Sea, affecting mostly shallow populations (down to 30 m depth). Here we provide an assessment of the health status of mesophotic P. clavata populations down to 90 m depth to investigate a depth refuge hypothesis. Results show that the impact of marine heat waves decreases with depth, with a significant drop in mortality below 40 m depth. These observations support the hypothesis of a depth refuge from marine heat waves that may allow, at least temporarily, the maintenance of P. clavata in the Western Mediterranean Sea. The present study strongly advocates for further investigations and monitoring of the mesophotic zone to chart potential areas that could serve as deep refuge for gorgonians