HAL Clermont Université
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Isometric path complexity of graphs
No full textInternational audienceA set of isometric paths of a graph is "-rooted", where is a vertex of , if is one of the end-vertices of all the isometric paths in . The isometric path complexity of a graph , denoted by , is the minimum integer such that there exists a vertex satisfying the following property: the vertices of any isometric path of can be covered by many -rooted isometric paths. First, we provide an -time algorithm to compute the isometric path complexity of a graph with vertices and edges. Then we show that the isometric path complexity remains bounded for graphs in three seemingly unrelated graph classes, namely, hyperbolic graphs, (theta, prism, pyramid)-free graphs, and outerstring graphs. Hyperbolic graphs are extensively studied in Metric Graph Theory. The class of (theta, prism, pyramid)-free graphs are extensively studied in Structural Graph Theory, e.g. in the context of the Strong Perfect Graph Theorem. The class of outerstring graphs is studied in Geometric Graph Theory and Computational Geometry. Our results also show that the distance functions of these (structurally) different graph classes are more similar than previously thought. There is a direct algorithmic consequence of having small isometric path complexity. Specifically, we show that if the isometric path complexity of a graph is bounded by a constant, then there exists a polynomial-time constant-factor approximation algorithm for ISOMETRIC PATH COVER, whose objective is to cover all vertices of a graph with a minimum number of isometric paths. This applies to all the above graph classes
Understanding dopaminergic dose reduction following STN-DBS: mediation analysis
No full textInternational audienceBackground Levodopa equivalent dopaminergic dose (LEDD) reduction after subthalamic nucleus deep brain stimulation (STN-DBS) in Parkinson’s disease varies widely. Identifying predictors may guide patient selection and programming. Our objectives were to identify predictors of LEDD reduction and to test whether motor improvement mediates this association. Methods Data from 144 patients treated by STN-DBS were analysed. Predictors of LEDD reduction were selected using the Boruta algorithm, a machine-learning method comparing variable importance to randomised features and then tested in a structural equation model for direct and motor-mediated effects. Results Mean LEDD reduction was 41.7% (±38.2%) and motor improvement was 48.6% (±26.7%) at 1 year. Among the four predictors identified by Boruta, lower baseline LEDD (β=0.39, p=0.001), greater axial impairment (β=−0.25, p=0.003) and higher total volume of tissue activated (β=−0.17, p=0.031) were directly associated with lower LEDD reduction, independent of motor improvement. Sensorimotor STN overlap was not directly linked to LEDD reduction but was positively associated with motor improvement (β=0.34, p=0.001), which showed a trend-level effect on LEDD reduction (β=0.16, p=0.065). The total effect of sensorimotor STN overlap on LEDD reduction was not significant. Discussion Dopaminergic dose reduction after STN-DBS is constrained by preoperative axial symptoms and stimulation spread, independently of motor improvement, while sensorimotor STN overlap improves motor symptoms but not dose reduction. Integrating motor phenotype with anatomical guidance may enhance medication management post DBS
The BIOMASP+ project on biosphere-atmosphere exchanges and their role in air pollution in the subtropical megacity of São Paulo: motivations, methods and preliminary observations
No full textInternational audienceAir pollution, especially in urban areas, is the result of a complex mixture of natural and anthropogenic emissions and their atmospheric processing. It causes millions of premature deaths worldwide and affects plant metabolism, which in turn alters the emissions of Biogenic Volatile Organic Compound (BVOCs) by plants. By taking the subtropical Metropolitan Area of São Paulo (MASP) as a natural laboratory, the BIOMASP+ project (BIOsphere-atmosphere interactions in the Metropolitan Area of São Paulo - plus) a ims to evaluate the interplay between the biosphere and secondary pollution (ozone and SOA formation and aging). The Brazilian Atlantic Forest (Mata Atlântica) is the target ecosystem as the fifth biodiversity hotspot in the world. Here we present the scientific motivations of the project, its methodology and the preliminary observations from the Special Observation Periods of year 2023 (SOP1, 2, 3 and 4). BIOMASP+ is (i) integrative, by combining in-situ/remote/laboratory observations andmodeling, (ii) multidisciplinary, addressing micrometeorology, urban climate, atmospheric chemistry and biology. The project involves multiple nested scales: from leaf to above-canopy levels, from very short time (microseconds) to multi-year scale, from few millimeters (turbulence scale) to synoptic scale. In particular, the experimental effort relies on the implementation of two contrasting supersites (primary forest and urban forest) with a 30-m and 20-m flux towers, respectively, and a variety of state-of-the-art instruments. Ambient observations and the quantification of BVOC emissions have highlighted the complex interactions between meteorology, atmospheric composition of pollution, biogenic emissions of representative remnants of the Atlantic Forest and anthropogenic emissions
Yggdrasil: An Artifact-Based Framework for Hypermedia Multi-Agent Systems
No full textInternational audienceRecent years have brought renewed interest in Web-based Multi-agent Systems (MAS), primarily motivated by progress in the Web of Things, Distributed Knowledge Graphs, and Generative AI. Central to these developments is the flexible, autonomous use of hypermedia—for example, to discover knowledge, invoke device functionality, or use tools. However, existing frameworks for Web-based MAS typically lack support for working with hypermedia abstractions and controls. To fill this gap, this chapter presents a model and framework for hypermedia-based MAS. Our specific focus is on the environment as a first-class abstraction in MAS: agents are situated and embodied in a distributed hypermedia environment that (i) provides them with a uniform abstraction of the system and (ii) is instrumented with tools and resources they can discover and use to achieve their goals. Given a single entry point into the hypermedia environment, agents are enabled to “arrive-and-operate”: they use their prior knowledge and experience to achieve their goals by browsing hypermedia and exploiting action possibilities discovered at run time—mimicking how humans are supported by well-designed hypermedia environments today. We illustrate our approach through a demonstrator and discuss its benefits and drawbacks against an equivalent implementation without hypermedia
An integrated fuzzy AHP-fuzzy TOPSIS approach for multi-criteria decision-making framework in sustainable manufacturing process selection
No full textInternational audienceThe design of a sustainable manufacturing process is complex, as it requires balancing technological, economic, environmental, and social factors while dealing with uncertainties and conflicting criteria. This research is focused on the uncertainties in the preferences of decision-makers. This study introduces an integrated fuzzy AHP-fuzzy TOPSIS framework, offering a reliable and systematic approach to multi-criteria decision-making. Fuzzy AHP is used to assign accurate weights to criteria by incorporating expert input and addressing the vagueness of linguistic terms, while fuzzy TOPSIS helps rank the alternatives based on how close they are to an ideal solution. In addition, CRITIC method is implemented to find the objective weights of each criterion to identify which criteria require careful consideration and to ensure that the decisions made are best against uncertainties. A case study was conducted on selecting a manufacturing process for hydraulic manifolds, considering 15 distinct criteria such as cost, energy efficiency, material utilization, and functional performance. Three Alternatives were evaluated, these are: conventional manufacturing with 316 Stainless Steel, additive manufacturing with AlSi10Mg, and additive manufacturing with 316 Stainless Steel. The results demonstrated that additive manufacturing with 316 Stainless Steel emerged as the optimal solution, exceeding the other alternatives in terms of sustainability and functional performance. Sensitivity analysis using one at a time weight variations, confirmed the stability and reliability of the proposed methodology. The results highlight the framework’s adaptability to diverse scenarios and its capacity to provide useful insights for decision-makers. This study provides a practical, reliable and effective tool for promoting sustainable practices in manufacturing process selection by integrating sustainability principles and addressing the complexities of modern manufacturing
Lire le sol en archéologie : pratiques de terrain et regards croisés
No full textInternational audienceActes d'un colloque international visant à promouvoir la lecture interdisciplinaire du sol en archéologie sur le terrain, en s’appuyant en particulier sur l’apport des sciences de la Terre. Il s’agissait de faire le lien entre les choix effectués sur le terrain et les étapes qui en résultent (analyses, interprétations…), de favoriser la constitution de référentiels, de guides de bonnes pratiques et de sensibiliser à la reconnaissance des traits pédo-sédimentaires. Le cadre thématique du colloque n’impliquait pas de limite chronologique ou géographique. Toute approche sur des contextes archéologiques pouvait être retenue dès lors qu’il s’agissait de mettre en commun la compréhension du passé, l’étude des occupations, des activités humaines, de l’environnement et des horizons naturels ou anthropisés, dans le dialogue nécessaire entre archéologie et sciences environnementales. Quelles perspectives peuvent offrir l’analyse et l’interprétation des structures et des couches lorsqu’elles sont prises en compte dès les premières observations de terrain ? Comment faciliter cette démarche, rendre cette approche plus efficiente et fluide entre les différents acteurs ? Afin d’optimiser l’étude des sites tout en améliorant leur compréhension, il fallait également entamer une réflexion sur l’utilité de protocoles adaptés et d’outils d’aide à la décision qui peuvent varier de l’échelle intra site à l’échelle territoriale. Tous les acteurs impliqués sur le terrain étaient donc concernés par les échanges de cette rencontre
Search for ttbar resonances in final states with exactly one or two leptons using 140 fb of pp collision data at TeV with the ATLAS experiment
No full textInternational audienceA search for heavy spin-1 and spin-2 resonances decaying into a top-antitop-quark pair has been performed with 140 fb of proton-proton collision data collected by the ATLAS experiment at the Large Hadron Collider at a centre-of-mass energy of TeV. Final states with either exactly one electron or muon, or exactly two leptons (, or ), large missing transverse momentum, and two jets, at least one of which must be identified as likely containing a b-hadron decay, are considered. The search targets resonances with both narrow and broad widths relative to the detector resolution, and with masses in the range of 0.4-5.0 TeV. No significant deviation from the Standard Model prediction is observed. Exclusion limits are set on the production cross-section times branching ratio for hypothetical bosons, Kaluza-Klein gravitons, and Kaluza-Klein gluons that decay into top-quark pairs
A model-independent measurement of the CKM angle in the decays and ()
No full textInternational audienceA model-independent determination of the CKM angle is presented, using the and decays, with . This measurement is the first phase-space-binned study of these decay modes, and uses a sample of proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of fb. The phase-space bins are optimised for sensitivity to , and in each bin external inputs from the BESIII experiment are used to constrain the charm strong-phase parameters. The result of this binned analysis is , where the uncertainty includes both statistical and systematic contributions. Furthermore, when combining with existing phase-space-integrated measurements of the same decay modes, a value of is obtained, which is one of the most precise determinations of to date
Kaempferol and curcumin as fluorescent probes for DNA topologies: Integrated spectroscopic and computational study
No full textInternational audienceKaempferol (3,4′,5,7-tetrahydroxyflavone, KMP) and curcumin (diferuloylmethane, CUR) are naturally occurring polyphenolic compounds with broad therapeutic potential, including anticancer, antioxidant, and anti-inflammatory properties. Among their molecular targets, DNA plays a central role, particularly through interactions with non-canonical DNA structures such as G-quadruplexes (G4) and i-motifs (C4), which form in guanine-and cytosine-rich genomic regions, respectively. These structures regulate telomere maintenance, gene expression, and genomic stability, making them attractive drug targets. In this study, we investigate the binding behavior of KMP and CUR with G4, C4, and duplex calf thymus DNA (calf thymus (CT)-DNA) using an integrated spectroscopic and computational approach. Circular dichroism, UV-visible absorption, and fluorescence spectroscopy were used to monitor ligand-induced structural and photophysical changes. CUR exhibited pronounced solvatochromism, with emission maxima shifting according to solvent polarity and DNA topology and showed the strongest fluorescence enhancement in G4 DNA. KMP displayed excited state intramolecular proton transfer (ESIPT), with the highest tautomeric emission observed in G4 structures. However, G4 also facilitated ground-state anion formation at the 3-OH group of KMP, which suppressed ESIPT by interfering with intramolecular hydrogen bonding between C(4)=O and 3-OH. ESIPT was least prominent in C4, and moderate in duplex DNA, where anion formation was less favored. Displacement assays using ethidium bromide (EtBr) provided functional insight into the competitive binding dynamics, confirming groove and loop binding for both ligands in G4 and C4 DNA, while KMP also exhibited intercalative binding in duplex DNA. Molecular docking and molecular dynamics simulations corroborated these findings, revealing stable ligand-DNA complexes and specific interaction modes. This comprehensive approach highlights CUR as a polarity-sensitive reporter and KMP as a thermally and structurally responsive ESIPT fluorophore. Together, they represent promising tools for probing DNA topology and developing targeted molecular diagnostics or therapeutic strategies centered on nucleic acid structure recognition