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Coupling genetic and demographic data to reveal dispersal processes in emperor penguins
No full textInternational audienceDispersal is an ubiquitous phenomenon that affects the dynamics of the population and the evolution of natural populations; however, it is challenging to measure in most species.Furthermore, the influence of informed dispersal behaviors, referring to the non-random selection of breeding habitats by individuals, on species' responses to rapid global change is substantial but difficult to comprehend.Here, we present a modeling framework to assess the dispersal characteristics and behaviors of a metapopulation, when observations provide information on its neutral genetic structure for a restricted sampling of locations. Our mechanistic-statistical model couples a deterministic model capturing the spatio-temporal dynamics of four genetic clusters across all breeding colonies by integrating demographic processes with genetic projections, with a probabilistic observation model describing the probability to sample an individual from a given genetic cluster.We apply this new framework to the emperor penguin, a species living in Antarctica and currently experiencing habitat loss. The model estimates the species' dispersal distance, rates of emigration, and behaviors associated with dispersal (informed or random). By incorporating these estimations with satellite censuses of breeding colonies, we can identify environmental and demographic factors that influence the { dispersal} of emperor penguins. Finally, we provide new global population forecasts for emperor penguins that can inform conservation actions in Antarctica
Permittivity Characterization of Conductive and Corrosive LiBr Water Solutions, Method Validation up to 9 GHz Using a Low-Cost SMA Probe
No full textInternational audienceIn this article, we present a method for extracting the complex permittivity of high-conductivity solutions up to 9 GHz. Microwave measurements were performed using a low-cost SMA connector, employed as an open-circuit coaxial probe, which was subsequently brought into contact with the liquids under characterization. Compared to state-of-the-art techniques, this method offers the advantage of good accuracy while remaining simple to implement with a low-cost sensor. The affordability of the sensor is crucial because the sensor must operate in a corrosive environment. The use of existing but expensive commercial solutions is prohibitive. Therefore, sensor replacement must be straightforward and inexpensive in case of damage. Two permittivity extraction methods were studied, both relying on a straightforward experimental approach and knowledge of the complex permittivity of reference liquids (deionized water, ethanol, methanol). The technique was initially validated on saline solutions (NaCl) known from the literature before being applied to aqueous lithium bromide (LiBr water) solutions. Eight LiBr water solutions, known to be highly corrosive, were measured for LiBr mass concentrations ranging from 1% to 54% and for conductivities up to 14 S/m. The high conductivity of these solutions brings challenges to extract the real part of the permittivity, which is underestimated by both methods. In contrast, the imaginary part exhibits consistent results with variations strongly correlated to the concentration. Notably, an inversion of the direction of variation was observed for mass concentration in LiBr exceeding 35% aligning with the conductivity curve
Interactive platforms for solar energy planning in smart cities: A state-of-the-art review of solar cadasters
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Functional alignment in robotic‐assisted total knee arthroplasty for valgus deformity achieves safe coronal alignment and excellent short‐term outcomes
No full textInternational audiencePurpose Functional alignment (FA) in total knee arthroplasty (TKA) prioritizes soft tissue balancing and anatomical restoration without systematic correction to neutral alignment. Most studies have focused on varus deformity, with little evidence available about FA in valgus deformity. The hypothesis of the present study was that FA in robotic‐assisted TKA for valgus deformity would demonstrate correction of the coronal alignment and yield satisfactory short‐term outcomes. Methods This retrospective study included 58 patients with valgus coronal alignment (hip–knee–angle [HKA] ≥ 183°) who underwent robotic‐assisted TKA using the FA technique with a minimum of 1‐year follow‐up. Outcomes were assessed through the Knee Society Score (KSS), Oxford Knee Score (OKS), Forgotten Joint Score (FJS) and radiographic measurements of alignment and phenotypes. Complication and revision rates were also analyzed. Results The cohort included 39 females and 19 males with a median age of 70. Post‐operatively, 86.2% of cases achieved coronal alignment within the safe zone (HKA 177–183°). Significant improvements were observed in KSS (part 1: 69.5–95, part 2: 65–94, p < 0.001), while OKS and FJS exhibited optimal outcomes. Two complications were recorded: one aseptic loosening (1.7%) and one early infection (1.7%). Kaplan–Meier survival analysis indicated favourable implant survivorship at a median follow‐up of 18 months. Conclusion FA in image‐based robotic TKA is a safe and effective approach for patients with valgus deformity. This procedure resulted in a modest correction of the coronal alignment, where no soft tissue releases were needed. The majority of the cases fell within the target coronal alignment boundaries by only accommodating the individual laxities, suggesting the aim of FA to restore each knee's pre‐pathological alignment. Level of Evidence Level IV
Impact of coolant operation on performance and heterogeneities in large proton exchange membrane fuel cells: A review
No full textInternational audiencePEMFCs’ operation entails the presence of heterogeneities in the generation of current, heat and water along the active surface area. Indeed, PEMFCs are open systems, and as such, operating heterogeneities are inherent to their operation. A review of the literature reveals numerous attempts to achieve uniform current density distribution. These attempts are primarily focused on bipolar plate design and operating conditions, with the underlying assumption that uniform current density correlates with enhanced performance. Most studies focus on the influence of gas flow-field design and inlet hydrogen and air flow conditioning, and less attention has been paid to the coolant operating condition. However, uncontrolled temperature distribution over a large cell active surface area can lead to performance loss and localized degradations. On this latter point, we notice that studies to date have been confined to a narrow range of operating conditions. It appears that complementary durability studies are needed in order to obtain in-depth analyses of the coupled influence of temperature distribution and gas humidification in large PEMFCs
Increased drying threatens alpine pond biodiversity more than temperature increase in a changing climate
No full textInternational audienceClimate change is one of the main drivers of biodiversity decline. Rapidly changing climate in the form of warming, drying, and habitat isolation causes freshwater species to change their spatial extent, as most species have little capacity for in situ responses. However, the relative contribution of these three effects to freshwater species' changing spatial distributions is actively debated. To shed light on this debate, we explored temperature, hydroperiod, and habitat connectivity effects on alpine pond species occupancy probabilities in the northern French Alps. We studied alpine ponds as ideal test systems because they face climate change effects more rapidly, and in more concentrated areas, than any other freshwater ecosystem. We used multispecies occupancy models with three biological groups (amphibians, macrophytes, and Odonata) to examine contrasting responses to climate change. Contrary to expectations, temperature was not the main driver of species occupancy probabilities. Instead, hydroperiod and connectivity were stronger predictors of species occupancy probabilities. Furthermore, temperature increases had the same effect on occupancy probabilities of non-alpine specialist and alpine specialist species. Nonetheless, temperature disproportionately affected a greater number of specialist species compared with non-alpine specialists. We conclude that climate change mitigation will primarily benefit a greater number of alpine specialist species than non-alpine specialists. Finally, we suggest that enhancing our understanding of freshwater hydroperiods will improve our predictions of climate change effects on freshwater species distributions
Millennial axially symmetric Magneto-Coriolis modes in Earth’s fluid core
No full textInternational audienceSUMMARY Magneto-Coriolis (MC) modes in Earth’s fluid core involve oscillations sustained by the combined effect of the Lorentz and Coriolis forces. Here, we investigate the properties of MC modes that involve purely axisymmetric flow, which we term axiMC modes. We provide a basic description of the wave dynamics of these modes, and simple predictions for the expected scalings of their frequency , decay rate and quality factor Q based on a uniform ambient magnetic field. In particular, Q scales with the Elsasser number , which depends on the square of the r.m.s. strength of the azimuthally averaged meridional field. When , and axiMC modes may be excited; when , and axiMC modes revert to quasi-free magnetic decay modes. We present computations of axiMC modes in an inviscid, electrically conducting sphere for two idealized ambient magnetic field configurations, a uniform axial field and an axial poloidal field. We show that a flow gradient in the axial direction is a key property of axiMC modes. For the uniform axial field, , and Q follow the scalings expected for a uniform field. For the axial poloidal field, the structure of the modes changes substantially when , becoming more concentrated in regions of lower field strength. The combination of this structural change and advection of field lines by flow significantly increases , resulting in a Q that remains close to 1 even at high . For a magnetic field strength inside the Earth’s core of a few mT, the gravest axiMC modes are expected to have periods in the range of one thousand to a few thousand years and a Q not substantially above 1. AxiMC modes may be connected to a part of the observed millennial changes in Earth’s magnetic field, may exchange axial angular momentum with the mantle, and hence may also explain a part of the observed millennial changes in length of day
La princesse, la Pin-up ou la sorcière, le tarzan, le gros machin ou le maladroit : les affiches hautes en stéréotypes d’un festival de BD où l’éléphant a remplacé King Kong
No full textNational audienceChoqués par les affiches du Festival International de la BD de Chambéry exposées sous les arcanes de la ville, nous les analysons pour montrer la façon dont les stéréotypes genrés sont véhiculés dans l'espace public
Sustaining continuous improvement programs - proposition of influential elements and a maturity-benchmark model
No full textInternational audiencePurpose The purpose of this paper is to shed light on the studies regarding the influential elements that contribute to the sustainability of continuous improvement (CI) programs. It aims to define the notion of sustainability and to identify and explore the influential elements that could encompass such a definition. Design/methodology/approach A comprehensive literature review was conducted to categorise various interpretations of sustainability into distinct dimensions. This approach also identified 16 influential elements that have the potential to sustain CI programs. A self-assessment survey involving 80 French companies was used to evaluate these elements through the Plan, Do, Check, Act framework. In addition, a maturity-benchmark model is introduced to help evaluate the degree of maturity of the most influential elements of CI programs. Findings The results highlight the inherent paradox in sustaining CI programs, where robustness and adaptability must coexist. The study identifies a relationship between influential elements and organisational maturity levels, offering actionable insights to help companies advance through these stages. Human-centered elements, such as leadership and employee engagement, have the greatest impact on CI sustainability, emphasizing the importance of fostering a people-centric culture. Conversely, operational elements are less influential, suggesting a need for balanced strategies. Originality/value This paper discusses a topic that is rarely addressed, namely, how to sustain CI programs within a CI framework. This paper provides a novel synthesis of influential elements and their relationships to organisational maturity within a CI framework, challenging traditional static views of sustainability. By emphasizing the dynamic and evolving nature of CI programs, it bridges theory and practice, offering organisations a practical model for continuous reassessment and adaptation
AutoKnots: Adaptive Knot Allocation for Spline Interpolation
No full textInternational audienceIn astrophysical and cosmological analyses, the increasing quality and volume of astronomical data demand efficient and precise computational tools. This work introduces a novel adaptive algorithm for automatic knots (AutoKnots) allocation in spline interpolation, designed to meet user-defined precision requirements. Unlike traditional methods that rely on manually configured knot distributions with numerous parameters, the proposed technique automatically determines the optimal number and placement of knots based on interpolation error criteria. This simplifies configuration, often requiring only a single parameter. The algorithm progressively improves the interpolation by adaptively sampling the function-to-be-approximated, , in regions where the interpolation error exceeds the desired threshold. All function evaluations contribute directly to the final approximation, ensuring efficiency. While each resampling step involves recomputing the interpolation table, this process is highly optimized and usually computationally negligible compared to the cost of evaluating . We show the algorithm's efficacy through a series of precision tests on different functions. However, the study underscores the necessity for caution when dealing with certain function types, notably those featuring plateaus. To address this challenge, a heuristic enhancement is incorporated, improving accuracy in flat regions. This algorithm has been extensively used and tested over the years. NumCosmo includes a comprehensive set of unit tests that rigorously evaluate the algorithm both directly and indirectly, underscoring its robustness and reliability. As a practical application, we compute the surface mass density and the average surface mass density for Navarro-Frenk-White and Hernquist halo density profiles, which provide analytical benchmarks. (abridged