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Impact of fertilization strategies on Phytolacca americana phytoextraction of rare earth elements from modified bauxite residue
No full textInternational audienceRare earth elements (REEs) are critical materials facing supply challenges, making their recovery from secondary sources increasingly important. With increasing interest in developing eco-friendly technologies for metal extraction, this study investigated the potential of Phytolacca americana-a known REE hyperaccumulator plant-for REE extraction from bauxite residue (BR), a by-product of alumina extraction. Indeed, BR contains promising concentrations of REEs but presents severe constraints for plants growth due to its high pH, salinity and nutrient deficiency. Due to its unsuitability for supporting plant growth, BR of different origins (i.e. lateritic or karstic bauxite ore) requires modification through gypsum input to obtain modified bauxite residue (MBR) with lower salinity and alkalinity. Here we applied several MBR fertilization treatments involving organic (i.e. sewage sludge or compost) or mineral (mineral nutrient solutions with/without P) amendments to assess their effects on P. americana growth and REE phytoextraction. The results revealed efficient P. americana growth in MBR following organic amendment, while the physicochemical characteristics of these amendments significantly modulated the REE extraction yield. Notably, phosphorus availability emerged as a key determinant with a major impact on the REE phytoextraction efficiency from MBR. The use of amendments containing P reduced the REE phytoextraction efficiency up to 94%, while the absence of P in the amendment appeared to enhance REE uptake up to 16-fold. This suggests that P availability modulated REE phytoextraction from MBR, likely through P-induced acquisition mechanisms. Managing the growth substrate nutritional status is thus essential to enhance the efficiency of REE phytoextraction from B
Les communs urbains comme formes renouvelées de la participation : Le cas des tiers-lieux culturels
No full textInternational audienceThis article addresses the question of the emergence of urban commons as innovative forms of citizen participation in urban manufacturing, with a special focus on cultural third places. These spaces, rooted in a critique of neoliberal urban models, are analyzed as experimental labs developing original participatory dynamics, with strong roots in the social and solidarity economy.Cet article traite de l'émergence de l’agir en commun dans les tiers lieux culturels comme formes renouvelées de participation citoyenne dans la fabrication urbaine Ces espaces, ancrés dans une critique des modèles urbains néolibéraux, se présentent comme des laboratoires d'expérimentation de dynamiques coopératives originales avec un fort ancrage dans l’économie sociale et solidaire
How can NIRS contribute to help growers to manage the fruit quality of fig and prickly pear?
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Routes d'Orient et d'Occident
No full textEn croisant les approches et en interrogeant plusieurs types de sources écrites ou archéologiques, les études réunies ici ouvrent de nouvelles perspectives à l’étude de la route médiévale dans les différentes manifestations de sa matérialité : son tracé, son entretien, son rapport au paysage naturel et anthropique. Ce dossier traite aussi de l’implication des pouvoirs politiques dans la fondation, le contrôle et l’exploitation fiscale et économique de ces grandes infrastructures territoriales
The Relationship Between Grazing Pressure and Environmental Factors Drives Vegetation Fragmentation Across Global Drylands
No full textInternational audienceAim To evaluate how grazing pressure, a key land‐use factor, interacts with climatic, vegetation, and soil variables to shape the fragmentation of perennial vegetation across drylands globally. Location 171 plots across 25 countries on six continents. Time Period Field data: 2016–2019. Major Taxa Studied Perennial grasses, shrubs, and woody plants. Methods We conducted a standardised field survey across 171 45 m × 45 m plots to assess grazing pressure, vegetation, and soil properties. Vegetation fragmentation was quantified using three patch‐based metrics derived from high‐resolution satellite images. Linear mixed‐effects models were used to relate fragmentation to climatic, vegetation, and soil variables. Predictor importance was assessed through multi‐model inference and validated using a random forest approach. Results Vegetation fragmentation increased with aridity, and this effect was 4.7 times stronger under high grazing pressure than under low pressure. The most influential interactions involved grazing pressure with soil amelioration (49.7% importance) and with vegetation cover (44.6%). Soil amelioration—measured as the enrichment of soil organic carbon beneath vegetation—reduced fragmentation, especially under high grazing pressure. In contrast, the ability of vegetation cover to sustain large patches diminished as grazing intensity increased. Soil amelioration was strongly linked to the proportion of facilitated plant species ( p < 0.01), whereas soil organic carbon alone—beneath vegetation ( p = 0.37) or in bare areas ( p = 0.94)—was not significantly related. Main Conclusions Grazing pressure and aridity interact to intensify vegetation fragmentation, potentially accelerating land degradation in drylands under future climate and land‐use scenarios. Mitigating this fragmentation requires not only enhancing vegetation cover but also promoting plant–soil facilitation processes, especially under high grazing pressure. These findings underscore the critical role of plant‐driven soil amelioration in maintaining ecosystem structure and resilience across global drylands
Le littoral, une "ligne de front" ? Habiter et aménager les espaces côtiers dans un contexte de risques accrus venus de la mer.
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L’accueil de nouveau-nés évacués de Mayotte : tensions et redéfinition des pratiques et identités professionnelles en néonatologie à La Réunion
No full textInternational audienceDue to overcrowding at the neonatal unit in Mayotte, newborn babies are sometimes transferred to hospitals on Reunion Island, another French overseas territory. These transfers are by air via the EVASAN medical evacuation system. This article is based on research conducted in a Reunion neonatology ward that receives transferred newborns, accompanied or not by their mothers. The article explores the impact on the practices and professional identities of nurses and nursery auxiliaries. These new patients arrive in a ward with limited resources, resulting in an increased workload. The presence of the mothers is deemed necessary for the well-being of the children. However, their being there introduces a social dimension to the hospital. This creates ethical tensions and blurs professional boundaries within a context where these patients are not considered a priority. It is also assumed that their care will be temporary.En raison de la saturation du service de néonatologie du centre hospitalier de Mayotte, il arrive que des nouveau-nés de parents résidant à Mayotte soient transférés dans un centre hospitalier de La Réunion, par le dispositif d’évacuation sanitaire EVASAN. Cet article repose sur une recherche de terrain dans un service de néonatologie de La Réunion. Il explore les effets de l’accueil de ces nouveau-nés évacués, accompagnés ou non de leur mère, sur les pratiques et les identités professionnelles des infirmières et auxiliaires puéricultrices. L’arrivée de ces nouveaux publics, dans un service peu outillé pour les accueillir dans de bonnes conditions, se traduit par une surcharge de travail. La présence des mères, si elle est jugée nécessaire pour le bien-être de l’enfant, fait entrer la question du social à l’hôpital, engendrant tensions éthiques et brouillage des rôles professionnels, dans un contexte où ces publics apparaissent non prioritaires et où leur accueil est perçu comme provisoire
DeepCollar: a precise and reliable high throughput, method for phenotyping maize stem elongation, collar appearance, leaf azimuth and individual collar height from temporal series of multi-view images
No full textInternational audienceHigh-throughput image-based plant phenotyping platforms allow following the dynamics of development of thousands of individuals of plants and understanding of the control of growth as a function of genotypic and environmental cues. We propose DeepCollar, a method for quantifying maize stem growth together with dynamics of appearance and positioning of individual collars (leaf insertion points). First, we used a deep learning detection model (YOLOv4) to detect collars in a time series of images of maize plants. Stem length dynamics was estimated as the highest collar height on a given date. The kinetics of individual collar positions and ranks were calculated first using a peak detection algorithm on a time-density plot of collar heights, where the peaks correspond to the 'plateau' reached by stabilized collars. The left / right labeling of the collars belonging to a plateau was then used together with the viewing angle to estimate leaf azimuths. An automatic clustering algorithm enables the association of detected collars with the plateau they reach. Finally, collar emergence dates were estimated as the date at which the stem first reached a plateau. To evaluate the method, we developed a dedicated annotation tool that selects the best control images and allows the user to easily check and remove false-positive detected plateaus. This check was performed on 1,000 plants imaged 40 days from 12 directions. The results showed that 98% of the collars were detected. For 75% of the plants, the algorithm detected 100% of the plateaus without errors. Furthermore, 20% of the plants exhibited false positive plateaus, which the users easily removed. Only 3 to 5% of the plants displayed too many errors and were tagged as 'unsolved' by the annotator. The annotation process took around 15s per plant, which is acceptable for checking 97% of the plants with error-free precision. Overall, this study demonstrated that the growth of the maize stem and the height of the individual collar is measurable with very high reliability on a phenotyping platform, at the cost of a few hours of human annotation post-processing
The use of vermicompost from urban organic waste leads to a sustainable increase of earthworm abundance: a three-year study in a crop field converting to organic farming
No full textInternational audienceThe management of organic matter in sustainable agriculture remains challenging in the 21st century. For farms located close to large cities, the organic fraction of municipal solid waste (OFMSW) is a potential resource to improve soil biological quality. However, this fraction can be processed in very different ways: compost, digestate, or vermicompost. We carried out a three-year trial to compare the effects on earthworm communities of two successive applications of such products at two doses (except for digestate) in a field crop recently converted to organic farming and no tillage. The abandonment of tillage led to a marked increase in the soil bulk density (from 1.25 to 1.45 g cm−3) and an associated and continuous decrease in the number of juvenile earthworms in all plots. For abundance of adult earthworms, compost had no effect, whereas digestate led to a large and rapid increase immediately after each application. By contrast, vermicompost steadily increased adult earthworm abundance (+33 to + 90 % compared to the control, depending on the sampling dates). Similar results were observed for earthworm biomass. In this trial, highly dominated by endogeics (80 % of the abundance), no difference between treatments was observed for the temporal variation of each species. However, Aporrectodea caliginosa abundance greatly increased after the first application, whereas Aporrectodea icterica only increased after the second application. The impact of vermicompost on earthworm communities has never been studied under field conditions so far, but this product seems promising for farmers who may seek to benefit from the services provided by earthworms
Print exposure and reading development in the French educational context: A systematic review
No full textInternational audienceThis systematic review investigates the role of print exposure in reading development within the French education system and discusses its implications for international research. Background: France’s declining performance in international reading assessments highlights the need to better understand literacy-related factors. Objectives and Methods: We synthesized findings from studies on diverse forms of print exposure—including home literacy environments and educational interventions—focusing on how these factors predict literacy outcomes. We also critically evaluated common measures of print exposure, from self-reports to print exposure checklists, and assessed their conceptual clarity and predictive validity. Results: Consistent with international evidence, print exposure and, more broadly, the home literacy environment support literacy development. However, in France, their impact appears more limited, likely due to the strong influence of socioeconomic factors and a centralized, school-driven educational system that reduces parental involvement. Conclusion/Implications: We propose an integrative framework that distinguishes direct measures of print exposure from distal indicators (e.g., number of books at home) often confounded with socioeconomic status. We also suggest incorporating additional variables, such as non-print activities that foster language and cognitive development, such as music training, play, and high-quality parent–child interactions. To strengthen future research, we recommend adopting a nested incremental approach to identify a parsimonious set of predictors that maximize both reliability and explanatory power