Hal - Université Grenoble Alpes
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Is the potential stability of forage resources under climate variability linked to transhumance patterns? An approach for sheep farming systems based on vegetation agroecological properties
No full textInternational audienceContext: Climate change, and in particular increased climate variability, is challenging the functioning of agropastoral livestock farms by impacting the availability of forage resources. Transhumant agropastoral systems, based on year-round herd mobility, mobilize a diversity of forage resources across time and space, which can potentially be a key factor in the stability of these forage resources in the face of climatic variability.Objective: This paper presents an original multiscale functional approach to evaluate the role of vegetation for forage resource stability in relation to herd mobility patterns (altitudinal and latitudinal gradients) in transhumant sheep systems (TSS) in the French Alps.Methods: We developed a set of indices that can provide information on forage stability at the farm level. These indices are based on (i) agro-ecological properties (based on the taxonomic and functional composition of vegetation) at the plot level combined at the farm level by the relative area of the plots and the distribution of the values of these indices, and (ii) the diversity of vegetation types within the farm. This approach was implemented on 12 sheep transhumant farms, representing a diversity of mobility gradients. We then measured the relationship between four categories of forage stability indices and herd mobility patterns. Results and conclusions: At farm level, we found positive correlations between the diversity of vegetation types and the range of altitudinal mobility, as well as between indices of distribution of vegetation functional characteristics (e.g., mean leaf dry matter content of plots) and the range of latitudinal mobility. Our results support the idea that differences in mobility gradients, whether along latitudinal or altitudinal gradients, provide access to different forms of complementarity that contribute to forage resource stability. However, our results also reveal trade-offs at the farm level between different dimensions of forage stability - particularly between productivity-related and those capturing plot's functional complementarity stability indices. Thus, forage resource stability in the face of climatic variability appears to be multidimensional, depending onthe combination of different properties carried by the vegetation - no single indicator of forage potential stability prevails across all systems. Our framework highlights various pathways to forage resilience in a context of increasing climate variability.Significance: This multiscale methodology, combining functional indices and scaling-up processes, offers a transferable framework to assess resource stability. It can be applied beyond transhumant livestock systems and mobilized in research projects addressing the resilience of diverse socio-ecological systems under climate variability
Tara Polaris expeditions: Sustained decadal observations of the coupled Arctic system in rapid transition
No full textThe coupled Arctic system is in rapid transition and is set to undergo further dramatic changes over the coming decades. These changes will lead most likely to an ice-free ocean in summer, expected before mid-century. The Arctic will become more strongly influenced by atmospheric and oceanographic processes characteristic of mid-latitudes, increasing the prevalence of contaminants and new biological species. This ongoing transition of the Arctic to a new state necessitates systematic monitoring of all sentinels (variables that make an essential contribution to characterizing the Earth's state) to improve our understanding of the system, enhance forecasting and support knowledge-based decisions. Here, we describe a sustained multi-decadal observation program to be implemented on the Tara Polar Station between 2026 and 2046. The monitoring program is designed as a series of year-long drift expeditions, called Tara Polaris, in the central Arctic Ocean, covering all seasons. The multidisciplinary data will bridge ecological, geochemical, biological, and physical parameters and processes in the atmosphere, sea ice and ocean. In addition, data collected with consistent methodologies over a 20-year period will make it possible to distinguish long-term trends from seasonal and interannual variability. In this paper, we discuss specific measurement challenges in each compartment (i.e., atmosphere, sea ice and ocean) along key sentinels and the most pressing scientific questions to be addressed. The expected outcomes of the Tara Polaris program will enable us to understand and quantify the main feedbacks of the coupled Arctic system, with their seasonal and interannual trends and spatial variability.</div
L'art de gouverner les prisons au Niger
No full textInternational audienceS’appuyant sur plusieurs séjours de recherche au Niger entre 2018 et 2023, cet ouvrage explore l’exercice de l’autorité dans les prisons nigériennes, du quotidien carcéral jusqu’au sommet de l’appareil d’État. À travers une approche interdisciplinaire – croisant science administrative, sociologie, anthropologie, science politique et droit – il montre comment les acteurs de la Garde nationale du Niger gouvernent les prisons en s’appuyant sur certaines personnes détenues, érigées en relais d’autorité. Loin de traduire une faiblesse de l’État, cette délégation révèle une véritable stratégie de contrôle : division, surveillance et instrumentalisation du pouvoir pour maintenir l’ordre. En replaçant l’État au cœur de l’analyse des prisons africaines, Carole Berrih met en lumière le rôle central des acteurs et les logiques de domination qui traversent l’administration carcérale. Première étude consacrée au système pénitentiaire nigérien, cet ouvrage s’inscrit dans la dynamique des études carcérales africaines et propose une réflexion originale sur les formes contemporaines d’autorité et de gouvernement dans ces prisons
Dissipative Solutions to a Compressible Non-Newtonian Korteweg System with Density-Dependent Viscous Stress Tensor
No full textThe main objective of this paper is to prove that if capillarity effect is taken into account then there exist dissipative solutions to a system describing viscoplastic compressibleflows with density dependent viscosities in a periodic domain \T^d with . We calculate the relative entropy inequality and in consequence show existence of dissipative solutions and the weak-strong uniqueness for this system. Our result extends the recent result concerning the link between Euler--Korteweg and Navier--Stokes--Korteweg systemsfor Newtonian flows (when the viscosity depends on the density) [See D.~Bresch, M. Gisclon, I. Lacroix-Violet, {\it Arch. Rational Mech. Anal.} (2019)] to non-Newtonian flows
Coarse-grained physics-based modelling for tape casting of fuel-electrode supports in Solid Oxide Cells
No full textInternational audienceOptimising the tape casting process for fabricating NiO/YSZ cermet-based fuel-electrode supports in Solid Oxide Cells remains a resource-intensive challenge. Improving the green tape properties are often reliant on trial-and-error procedures or proprietary knowledge that is inaccessible to the broader scientific community. In this work, we use computational simulations as a powerful tool to link the manufacturing process to the final microstructure of the tape. A novel three-dimensional physics-based model is presented to simulate the slip preparation and the homogeneous drying process of the tape casting producing the fuel electrode support in Solid Oxide Cells. Our model is well-calibrated to experimental data, and we investigate the dried microstructure of the simulated support
Reclaiming monetary governance: how French convertible local currencies embed strong sustainability through participatory institutions
No full textInternational audienceThis article examines whether French convertible local currencies (CLCs) can operationalise strong sustainability. Drawing on a national survey (53 associations, 431 professionals, 786 users) and a case study of the Eusko, multivariate analysis shows that participatory governance—not territorial scope—is the key organisational predictor of ecological selectivity, including supplier screening and environmental charter adoption. Qualitative evidence clarifies that mixed commissions and collective reserve allocation embed sufficiency criteria in daily practice. However, mandatory one-to-one euro convertibility constrain aggregate impact by linking local money supply to national liquidity cycles and limiting public-sector use. The findings indicate that CLCs can foster sufficiency-oriented innovation where subsidiarity is matched by deliberative capacity, but broader systemic influence depends on regulatory reforms to expand fiscal subsidiarity and green refinancing options. The study contributes empirical evidence to debates on monetary plurality and sustainable provisioning
Exploring processability limitations of commercial hard carbon for negative electrodes of Na-ion batteries
No full textInternational audienceOptimizing electrode manufacturing processes for sodium-ion batteries (SIBs) is crucial for enhancing their performance and commercial viability. This study systematically investigates the influence of critical electrode fabrication parameters, including solid content, mass loading, and calendering, on commercial hard carbon (HC) electrode properties. Slurries prepared with 35 % and 40 % solid content (SC) demonstrated distinct rheological behaviours, directly affecting electrode mechanical stability and processability. The slurry with SC-35 % provided a better balance between manageable viscosity and robust mechanical stability upon drying, whereas SC40 % slurry exhibited higher viscosity, particle agglomeration, and poorer electrode mechanical integrity. Calendering was studied at compression degrees of 10 %, 20 %, and 30 %, revealing limited effectiveness in reducing porosity due to the intrinsic mechanical properties of HC, whereas, higher compression degrees led to structural damage. Electrochemical studies conducted in half-cells (HC vs. Na) and full-cells (HC vs. Na3V2(PO4)3) clearly indicated better electrochemical performance at moderate calendering degrees (10-20 %), effectively balancing mechanical integrity and electrical conductivity. This comprehensive study results in a useful experimental database in academic literature, underscoring the importance of precise control over slurry formulation and calendering parameters to achieve structurally robust electrodes, thus significantly enhancing the practical performance of SIBs
Measurement of inclusive dijet cross-sections in proton-proton collisions at TeV with the ATLAS detector
No full textInternational audienceInclusive dijet cross-sections have been measured in proton-proton collisions at a centre-of-mass energy of 13 TeV using data with an integrated luminosity of 140 fb, recorded by the ATLAS detector at the Large Hadron Collider during 2015-2018. Jets are identified using the anti- algorithm with a radius parameter of . The inclusive dijet double-differential cross-sections are measured first as a function of the invariant dijet mass and the half absolute rapidity separation between the two leading jets, , , and second as a function of the invariant dijet mass and the total longitudinal boost of the dijet system, , . The measured dijet system covers the invariant mass range from 240 GeV to almost 10 TeV, with dijet separation and dijet boost . The results are unfolded to the particle level and compared with state-of-the-art next-to-next-to-leading-order full colour perturbative QCD calculations, corrected for non-perturbative and electroweak effects
Memory and imagination
No full textInternational audienceThe consensus in twentieth-century philosophy was that memory is sharply distinct from imagination. This consensus has been challenged in recent years by a growing body of empirical research that reveals extensive similarities in the neural underpinnings of remembering the past and imagining the future and has gradually given way to a debate between "continuists" and "discontinuists" about the relationship between memory and imagination. This chapter begins by reviewing first-order arguments for continuism and discontinuism. It then discusses recent meta-level attempts to clarify the debate's central concepts, namely, memory and imagination. Finally, it discusses a recent attempt to characterize the continuist-discontinuist debate in terms of metalinguistic negotiation and then develops a novel approach to bringing conceptual clarity to the debate, outlining different ways in which the (dis)continuity question itself can be and has been interpreted-irrespective of the various possible construals of the concepts of memory and imagination identified by earlier meta-level approaches