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Cross-border data ecosystems impact on resilience: an exploratory study
No full textData ecosystems represent a promising avenue to support Disaster Risk Reduction (DRR) and resilience. Especially in fragmented settings such as cross-border regions, data ecosystems can foster data sharing and regulation among DRR actors. However, recent research has suggested that the creation and maintenance of data ecosystems is challenging. Overall, DRR actors still lack a comprehensive overview of the nature of the impact that a data ecosystem can have on its members. Despite the scarcity of cross-border data ecosystems for DRR, a comprehensive examination of their impact is necessary to support future investments. This research addresses this lack by thoroughly examining the case of the Italian French border. Through a qualitative research design, our research team has been collecting and analyzing data from observations, interviews and focus groups. Drawing on the Theory of Change (ToC), we propose a comprehensive model of the support from a cross-border data ecosystem for its members’ resilience. This research contributes to research on data ecosystem in the field of disaster management by highlighting the importance of nurturing data documentation, collaboration and trustful ties within data ecosystems
MS2DECIDE: Aggregating Multiannotated Tandem Mass Spectrometry Data with Decision Theory Enhances Natural Products Prioritization
No full textInternational audienceMass spectrometry‐based natural products (NPs) targeted discovery often relies on a complicated decision‐making process involving tedious comparison of exact masses data and tandem mass spectra‐based annotation tools output against various spectral reference libraries. To address this bottleneck, tandem mass spectrum to decision (MS2DECIDE) is presented which leverages decision theory and expert knowledge to aggregate the outputs of three widely used annotation tools (GNPS, Sirius, and ISDB‐LOTUS) and computes a recommendation for targeting NPs with regard to their potential novelty. We demonstrate, through two case studies, that MS2DECIDE reliably captures the novelty of natural products from their tandem mass spectra. MS2DECIDE is freely accessible on GitHub
Drawing a map of elections
No full textInternational audienceOur main contribution is the introduction of the map of elections framework. A map of elections consists of three main elements: (1) a dataset of elections (i.e., collections of ordinal votes over given sets of candidates), (2) a way of measuring similarities between these elections, and (3) a representation of the elections in the 2D Euclidean space as points, so that the more similar two elections are, the closer are their points. In our maps, we mostly focus on datasets of synthetic elections, but we also show an example of a map over real-life ones. To measure similarities, we would have preferred to use, e.g., the isomorphic swap distance, but this is infeasible due to its high computational complexity. Hence, we propose polynomial-time computable positionwise distance and use it instead. Regarding the representations in 2D Euclidean space, we mostly use the Kamada-Kawai algorithm, but we also show two alternatives. We develop the necessary theoretical results to form our maps and argue experimentally that they are accurate and credible. Further, we show how coloring the elections in a map according to various criteria helps in analyzing results of a number of experiments. In particular, we show colorings according to the scores of winning candidates or committees, running times of ILP-based winner determination algorithms, and approximation ratios achieved by particular algorithms.</div
The twin blow-up method for Hamilton-Jacobi equations in higher dimension
No full textInternational audienceIn this paper, we show how to extend the twin blow-up method recently developped by the authors (Comptes Rendus. Math., 2024), in order to obtain a new comparison principle for an evolution coercive Hamilton-Jacobi equation posed in a domain of an Euclidian space of any dimension and supplemented with a boundary condition. The method allows dealing with the case where tangential variables and the variable corresponding to the normal gradient of the solution are strongly coupled at the boundary. We elaborate on a method introduced by P.-L. Lions and P. Souganidis (Atti Accad. Naz. Lincei, 2017). Their argument relies on a single blow-up procedure after rescaling the semi-solutions to be compared while two simultaneous blow-ups are performed in this work, one for each variable of the classical doubling variable technique. A one-sided Lipschitz estimate satisfied by a combination of the two blow-up limits plays a key role
Classical Density Functional Theory: The Local Density Approximation
No full textInternational audienceWe prove that the lowest free energy of a classical interacting system at temperature with a prescribed density profile can be approximated by the local free energy , provided that varies slowly over sufficiently large length scales. A quantitative error on the difference is provided in terms of the gradient of the density. Here is the free energy per unit volume of an infinite homogeneous gas of the corresponding uniform density. The proof uses quantitative Ruelle bounds (estimates on the local number of particles in a large system), which are derived in an appendix
A non-controllability result for the half-heat equation on the whole line based on the prolate spheroidal wave functions and its application to the Grushin equation
No full textInternational audienceIn this article, we revisit a result by A. Koenig concerning the non-controllability of the half-heat equation posed on R, with a control domain that is an open set whose exterior contains an interval. The main novelty of the present article is to disprove the corresponding observability inequality by using as an initial condition a family of prolate spheroidal wave function (PSWF) translated in the Fourier space, associated to a parameter c that goes to ∞. The proof is essentially based on the dual nature of the PSWF together with direct computations, showing that the solution "does not spread out" too much during time. As a consequence, we obtain a new non-controllability result on the Grushin equation posed on R × R
Optimizers for the finite-rank Lieb-Thirring inequality
No full textInternational audienceThe finite-rank Lieb-Thirring inequality provides an estimate on a Riesz sum of the lowest eigenvalues of a Schr\"odinger operator in terms of an norm of the potential . We prove here the existence of an optimizing potential for each , discuss its qualitative properties and the Euler--Lagrange equation (which is a system of coupled nonlinear Schr\"odinger equations) and study in detail the behavior of optimizing sequences. In particular, under the condition \gamma>\max\{0,2-d/2\} on the Riesz exponent in the inequality, we prove the compactness of all the optimizing sequences up to translations. We also show that the optimal Lieb-Thirring constant cannot be stationary in , which sheds a new light on a conjecture of Lieb-Thirring. In dimension at , we show that the optimizers with negative eigenvalues are exactly the Korteweg-de Vries --solitons and that optimizing sequences must approach the corresponding manifold. Our work covers the critical case in dimension (Cwikel-Lieb-Rozenblum inequality) for which we exhibit and use a link with invariants of the Yamabe problem
Rates of convergence in long time asymptotics of an alignment model with symmetry breaking
No full textWe consider a nonlinear Fokker-Planck equation derived from a Cucker-Smale model for flocking with noise. There is a known phase transition depending on the noise between a regime with a unique stationary solution which is isotropic (symmetry) and a regime with a continuum of polarized stationary solutions (symmetry breaking). If the value of the noise is larger than the threshold value, the solution of the evolution equation converges to the unique radial stationary solution. This solution is linearly unstable in the symmetry-breaking range, while polarized stationary solutions attract all solutions with sufficiently low entropy. We prove that the convergence measured in a weighted L 2 norm occurs with an exponential rate and that the average speed also converges with exponential rate to a unique limit which determines a single polarized stationary solution
Effect of glioblastoma and brain radiotherapy on T-lymphocyte subpopulations in rodents
No full textISTCTInternational audienceIntroduction: Although lymphopenia is linked to immune suppression favoring tumor growth, the effect of different radiation types on specific T-lymphocyte subsets remains unclear. Among the T-lymphocyte subpopulations, CD8+-lymphocytes serve as key effectors in cancer immunity. This study aimed to examine the changes in T-lymphocyte subpopulations in both tumor-free and glioblastoma-bearing mice following brain-irradiation.Methods: The study was divided into two main phases. First, C57BL/6 mice, with or without glioblastoma (GL261 cells), received hemispheric brain-irradiation or no-treatment. T-lymphocyte subpopulations were analyzed using flow cytometry at various timepoint. The effect of tumor size and brain-irradiation on these cells was assessed using correlation analysis. Next, C57BL/6 mice were subjected to different brain-irradiation conditions. Blood samples were collected during and post-irradiation to analyze T-lymphocyte subpopulations, and tree-based modeling was used to determine radiation parameters impact on naïve CD8+-lymphocyte levels.Results: Glioblastoma reduced all T-lymphocyte subpopulations by day 15 post-inoculation. Radiotherapy decreased regulatory and effector CD4+-lymphocytes in both tumor-free and glioblastoma-bearing mice, but not naïve or memory CD4+-lymphocytes, in both tumor-free and glioblastoma-bearing mice. In tumor-free mice, radiotherapy had no effect on CD8+-lymphocytes, but reduced all CD8+-lymphocyte types in glioblastoma-bearing mice. Glioblastoma size negatively affected CD8+-lymphocytes. Brain-irradiation persistently reduced naïve and memory CD8+-lymphocytes, but effector and regulatory T-lymphocytes recovered. Exposure of lymph nodes to radiation worsened CD8+-lymphocyte reduction.Conclusion: These findings confirm that the presence of glioblastoma and brain-irradiation affect T-lymphocyte subpopulations in mice. The inclusion of lymph nodes in the irradiated area led to a long-term decrease in naïve CD8+-lymphocytes. Further mechanistic studies are needed to understand the molecular basis of radiation impact on T-lymphocyte subpopulations
“Antiracism for sale”: commodification, antiracialism, and the politics of antiracism campaigns in France
No full textInternational audienceAlthough antiracism campaigns have become central to debates over the meaning of "antiracism", little research has explored their specific dynamics or traced their evolution over time. This study situates contemporary discussions within a broader historical context by analyzing posters produced by mainstream French antiracist organizations from 1980 to 2019. By integrating critical race and critical marketing perspectives, our analysis identifies three dynamics characterizing the evolution of these campaigns over time, shaped by both antiracialism and commodification. Celebratory dehistoricization, where antiracism is detached from its historical roots and rebranded as feel-good narratives. Institutionalized depoliticization, shifting antiracism from grassroots activism into an institutional service managed by organizations focused on legal compliance. Consumer-oriented privatization, reducing racism to individual acts that can be fought through consumer actions. We further discuss how these dynamics intersect with gendered and class relations, and conclude by offering insights into what more meaningful antiracism campaigns might entail