Publications scientifiques de l'Université de Reims Champagne-Ardenne
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An Improved Fuzzy Logic Controller for Mobile Robots Navigation in Unknown Environments
No full textInternational audiencehis paper presents a dual Fuzzy Logic Control (FLC) system for robot naviga-tion in dynamic and unknown environments. The system comprises two FLCs:one for obstacle avoidance, utilizing laser scan data to detect and avoid obsta-cles, and another for goal-seeking, which computes the optimal path toward thetarget. To improve the performance and adaptability of the system, three keyinnovations are introduced: a fusion FLC to manage smooth transitions betweenthe two controllers, an enhanced obstacle avoidance mechanism that prioritizesavoidance directions, and a sub-goal generation block to handle blocked pathsand isolated regions. These innovations ensure more reliable, efficient, and safenavigation. The effectiveness of the proposed method is validated through numer-ical simulations in a Gazebo environment using ROS2 commands, demonstratingits ability to achieve smooth, fast, and collision-free motion in complex scenarios
Mariage, nullité et putativité : ne l'oublions pas, la bonne foi est toujours présumée !
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ACTB deletions or single-nucleotide loss-of-function variants: expansion and further delineation of the phenotype and review of the literature
No full textInternational audienceBackground Pathogenic gain-of-function or dominant-negative effect missense variations in ACTB are associated with a neurodevelopmental disorder characterised by intellectual disability (ID), seizures, sensorineural hearing loss, cerebral, renal and ocular abnormalities and dysmorphic features (Baraitser-Winter cerebrofrontofacial syndrome). ACTB encodes beta-actin, a highly conserved protein involved in cell motility, structure and integrity. Deletions including ACTB, and, more rarely, single-nucleotide loss-of-function variants in ACTB have been described in patients with a distinct phenotype including developmental delay, ID, microcephaly, growth restriction, cardiac and renal abnormalities and dysmorphic features. Methods We collected 14 individuals and 1 fetus carrying a heterozygous deletion including ACTB , and 4 individuals with a heterozygous truncating variant. Genotypic and phenotypic data were analysed. Furthermore, a comprehensive review of all cases reported to date was also undertaken. Results Twelve out of 17 individuals presented with ID, and 3 out of 17 with learning disabilities. Speech delay and behavioural abnormalities were observed in 15 out of 17 and 12 out of 17 individuals, respectively, motor delay in 9 out of 17 and growth restriction in 9 out of 18. Most of the individuals (13/18) had recognisable dysmorphic features. 11 anomalies were de novo, except for 1 deletion inherited from the mother. The size of the deletion varied from 125 kb to 1.6 Mb and could result from a fork stalling and template switching. Conclusion This study allowed us to better characterise the phenotype associated with the haploinsufficiency of ACTB, underlying the high prevalence of neurodevelopmental disorders (ID, speech and motor delay, behavioural abnormalities) and growth restriction in this recognisable syndrome
Metabolite diversity of Microcystis strains shows tight correspondence to genotype and may contribute to ecotype specificities
No full textInternational audienceMicrocystis is one of the most common bloom-forming cyanobacteria colonizing freshwater ecosystems worldwide. This genus remarkably produces numerous bio-active accessory metabolites, which are believed to be potentially involved in different ecological and/or physiological processes. However, their genuine contribution to the evolutionary success of Microcystis blooms remains undetermined. To better depict the potential relationship between the local genetic diversity of blooming Microcystis populations and their respective associated chemical diversity, we conducted a joint genomic and metabolomic analysis of 65 Microcystis strains collected from various lakes in France and surrounding Western European countries. Interestingly, both core and pan-gene phylogenetic analysis place 57 of these strains in 11 distinct genotypes with at least 2 genomes, being widely distributed along the entire Microcystis phylogeny and presenting specific signatures of accessory metabolite biosynthesis. The direct chemical analysis of metabolite diversity produced by these strains, cultured under laboratory conditions, reveals the production of stable metabolite cocktails, with minimal variations over replication, growth phases and culture conditions. Remarkably, these strains belonging to 11 different genotypes correspond to 13 distinct chemotypes according to an accurate one-chemotype-for-one-genotype rule. Furthermore, these genotypes also appear distinguishable regarding their respective ecotoxicological traits and might be considered as specific toxico-ecotypes. Overall, our investigations reveal that the production of accessory metabolites constitute well conserved chemical traits across the different Microcystis genotypes, suggesting these molecules may be involved in key adaptive and selective processes, that still remain underexplored.</div
A mirror deformation of Markov numbers
No full textWe introduce a deformed squared Markov equation given by X^2 + Y^2 + Z^2 + (q+q^(-1))(XY + YZ +XZ) = 3(1+q+q^(-1))XYZ. Symmetric solutions of this new equation present a remarkable factorization property which allows us to talk about their square roots. These square roots give a natural q-deformation of the Markov numbers that has not previously occurred in the literature. We call them mirror Markov numbers. We prove a characterization of mirror Markov numbers and discover a mutation rule, mirror mutation, to generate them all. We also prove a geometric realization of the corresponding mirror mutation on a once-punctured sphere with three orbifold points. Our mirror deformation leads to deformations of Fibonacci and Pell branches for which we give precise formulas. Furthermore, the deformed squared Markov equation specializes to many other very well known generalized Markov equations. We also obtain the super Markov numbers from a specialization of the deformed squared Markov numbers, which we use to prove a conjecture of Musiker
Comprehensive Analysis of Gypsum Mortar with Glass Waste Aggregates as a Substitute for Sand
No full textInternational audienceGypsum has been used as a building material for a long time due to its environmental friendliness, exceptional fire performance, and ease of use. However, it is also known to have poor moisture resistance and lower mechanical performance. Construction and demolition wastes, which can cause many environmental issues if not properly managed, are increasingly recycled as reinforcement materials in gypsum mortar. This study aims to assess the effect of incorporating fine glass waste aggregates into gypsum mortars on their physical, mechanical, and adhesive properties. The effect of replacing sand from 0% to 100% by glass waste in gypsum mortar was investigated using various tests and analyses including scanning electron microscopy (SEM), X-ray diffraction (XRD), thermal analysis (DTA and TGA), setting time, flexural and compressive strengths, adhesive, surface hardness, water absorption, thermal conductivity, and ultrasonic pulse velocity. The results obtained emphasize that glass waste can substitute sand in gypsum mortar, even when used at high replacement levels. Replacing all the sand in mortar with glass waste results in a 11% increase in porosity, a 9% decrease in density, and a 53% decrease in thermal conductivity, while still maintaining acceptable mechanical performances. The adhesive strength shows a great dependence on the nature of the substrate
Comparative quantification of Leishmania infantum in experimental phlebotomine sand fly infections using kDNA and single-copy Meta-1 gene qPCR assays
No full textInternational audienceBackground: Leishmaniasis is a parasitic disease transmitted by female sand flies and caused by protozoan parasites of the genus Leishmania. Accurate quantification of parasite load within vectors is essential for understanding transmission dynamics and vector competence. This study compares two quantitative polymerase chain reaction (qPCR) methods for detecting and quantifying Leishmania infantum in three experimentally infected sand fly species (Phlebotomus perniciosus, Phlebotomus argentipes, and Phlebotomus orientalis).Methods: One method targets kinetoplast minicircle DNA, which offers high sensitivity but limited quantitative precision, while the other targets the single-copy Meta-1 gene, providing more precise quantification but reduced sensitivity in low-level infections.Results: A positive correlation between the two molecular markers supports a combined approach to maximize both sensitivity and accuracy in surveillance and transmission studies. Following this methodological comparison, significant differences were observed in parasite proliferation among sand fly species and L. infantum strains, with Ph. orientalis confirmed as a highly competent vector for Leishmania donovani complex.Conclusions: Together, these findings highlight that combining high-sensitivity (kinetoplast DNA [kDNA]) and single-copy (Meta-1) targets enables both accurate and sensitive quantification of Leishmania infections in sand flies, improving the assessment of parasite-vector interactions
Membrane Deformation – Finite Elements – Parametric Shape Optimization on the Koch Snowflake
No full textWe introduce the finite element method to analyze a membrane with a Koch snowflake-shaped boundary. The fractal nature of this domain presents unique challenges due to its intricate boundary structure. Our approach involves discretizing the domain, estimating the error, and proving convergence. With these aspects addressed, we solve a shape optimization problem to determine the optimal thickness of the membrane. These findings provide valuable insights into how fractal boundaries affect structural performance and optimization
Multi-laboratory compilation of atmospheric carbon dioxide data for the period 1983-2024; obspack_ch4_1_GLOBALVIEWplus_v8.0_2026-01-13
No full textInternational audienceThis product is constructed using the Observation Package (ObsPack) framework [Masarie et al., 2014; www.earth-syst-sci-data.net/6/375/2014/]. The framework is designed to bring together atmospheric greenhouse gas (GHG) observations from a variety of sampling platforms, prepare them with specific applications in mind, and package and distribute them in a self-consistent and well-documented product. ObsPack products are intended to support GHG budget studies and represent a new generation of cooperative value-added GHG data products. This product includes 535 atmospheric methane datasets derived from observations made by 68 laboratories. Data for the period 1983-2024 (where available) are included
Pensée à somme nulle et fracturepolitique: À propos de : “Zero-Sum Thinking and the Roots of U.S. Political Divides”, par Sahil Chinoy, Nathan Nunn, Sandra Sequeiera et Stefanie Stantcheva, American Economic Review
No full textInternational audienceUne étude menée auprès de 20 400 répondants aux États-Unis montre que les personnes pour qui le monde se divise en perdants et en gagnants sont plus favorables à une redistribution plus égalitaire et à des politiques d’immigration plus restrictives