Parallel geodesics and minimal stable length of random groups

21 pagesWe show that for any pair of long enough parallel geodesics in a random group G(m, d) with m generators at density d < 1/6, there is a van Kampen diagram having only one layer of faces. Using this result, we give an upper bound, depending only on d, of the number of pairwise parallel geodesics in G(m, d) when d < 1/6. As an application, we show that the minimal stable length of a random group at density d < 1/6 is exactly 1

Plinthine/Kôm el-Nogous I. Habitat, ressources et culture matérielle de deux quartiers d’un village viticole à l’époque saïto-perse

International audienc

Roads and Rations: Logistics and Storage on the Ptolemaic Route from Edfu to Berenike (Egypt)

International audienceThis paper reconstructs the logistical and storage systems that underpinned the Ptolemaic road linking Edfu to Berenike, a route created in the third century BCE to support large-scale elephant-hunting expeditions and sustained movement across Egypt’s Eastern Desert. Drawing on archaeological evidence from the road stations at Bir Samut and Abbad, combined with extensive ostraca documenting provisioning and administration, we examine how foodstuffs, especially grain, were transported, stored, processed, and redistributed in an environment defined by extreme aridity and risk.We argue that the success of this route depended not simply on the construction of wells and stations, but on an integrated system of storage technologies designed to manage periodic surges in consumption while minimizing spoilage and loss. Grain, water, and other provisions were stockpiled in advance at major stations, redistributed to smaller installations, and issued to station personnel, supply caravans, and expedition members according to tightly regulated ration systems. Amphoras played a central role in this process. Far from serving only as transport containers, Upper Egyptian Ptolemaic amphoras functioned as flexible storage devices at multiple scales: as sealed containers for bulk provisioning, as standardized volumetric units that facilitated accounting, and later as reused installations embedded in floors for short-term storage within kitchens and workspaces.The paper situates these practices within broader discussions of Ptolemaic statecraft, emphasizing how storage infrastructures reveal administrative priorities and attitudes toward risk, surplus, and control. The standardized capacities of amphoras, their adaptation to camel transport, and their close correspondence with accounting units underscore the degree to which material culture was shaped by bureaucratic needs. At the same time, the archaeological record reveals a parallel layer of improvisation in food processing and secondary storage, reflecting the lived realities of residents and travelers operating within this centralized system.Cet article propose une reconstitution des systèmes logistiques et de stockage attestés sur la route ptolémaïque reliant Edfou à Bérénice, un axe crée au IIIe s. av. J.-C. pour permettre le passage de très grandes expéditions de chasse à l’éléphant et plus largement pour favoriser les circulations dans le désert Oriental égyptien à cette période. En nous appuyant sur les données archéologiques issues des stations routières de Bir Samut et d’Abbad, ainsi que sur un corpus abondant d’ostraca documentant les pratiques d’approvisionnement et d’administration des stocks, nous examinons les modalités de transport, de stockage, de transformation et de redistribution des céréales dans un environnement marqué par des conditions extrêmes.Nous montrerons que le succès de cette route n’a pas reposé uniquement sur la construction de puits et de stations, mais également sur un système intégré de technologies de stockage conçu pour gérer des pics périodiques de consommation tout en limitant les pertes et l’altération des denrées. Les céréales, l’eau et les autres provisions étaient stockées à l’avance dans les stations principales, redistribuées vers des stations secondaires, distribuées au personnel des stations, aux caravanes de ravitaillement et aux membres des expéditions selon un système de rations strictement réglementé. Les amphores ont joué un rôle central dans ce dispositif. Loin de servir uniquement de conteneurs de transport, les amphores ptolémaïques de Haute Égypte ont servi de dispositifs de stockage polyvalents à différentes échelles : conteneurs hermétiques pour l’approvisionnement en vrac, unités volumétriques standardisées facilitant la comptabilité, puis, dans un second temps, dispositifs réemployés pour le stockage de courte durée dans les cuisines et les espaces de travail des stations.L’article inscrit ces pratiques dans une réflexion plus large sur le fonctionnement de l’État lagide, en soulignant la manière dont les infrastructures de stockage témoignent de certaines priorités dictées par l’administration, ainsi que les attitudes des membres de l’administration face au risque, au surplus et au contrôle. Les capacités standardisées des amphores, leur adaptation au transport à dos de chameau et leur étroite correspondance avec les unités comptables mettent en évidence le degré auquel la culture matérielle a pu être façonnée par les exigences bureaucratiques. Parallèlement, les vestiges archéologiques révèlent un niveau d’improvisation dans les pratiques de transformation alimentaire et de stockage secondaire au sein des stations, reflet des réalités vécues par les résidents et les voyageurs opérant au sein de ce système centralisé

Amoeba Measures of Random Plane Curves

41 pages, 1 figureInternational audienceWe prove that the expected area of the amoeba of a complex plane curve of degree $d$ is less than $\displaystyle{3\ln(d)^2/2+9\ln(d)+9}$ and once rescaled by $\ln(d)^2$, is asymptotically bounded from below by $3/4$. In order to get this lower bound, given disjoint isometric embeddings of a bidisc of size $1/\sqrt{d}$ in the complex projective plane, we lower estimate the probability that one of them is a submanifold chart of a complex plane curve. It exponentially converges to one as the number of bidiscs grow to $+\infty$

Un aveugle peut-il refuser de voir ? Optique, critique sociale et cécité à la fin du règne de Louis XV

International audienceIn 1771, an anonymous philosophical tale was published, L'Aveugle qui refuse de voir. The eponymous character and that of the oculist who intends to give him sight are two literary effects of the optical and ophthalmological revival of the 17th and 18th centuries, and each embodies a voice of the Enlightenment. The blind man, through the prism of his blindness, produces a critique of the hierarchical and unequal society of the Ancien Régime, insofar as it is based on the sense of sight.En 1771 est publié un conte philosophique anonyme, L’Aveugle qui refuse de voir. Le personnage éponyme et celui de l’oculiste qui entend lui donner la vue constituent deux effets littéraires du renouveau optique et ophtalmologique des XVIIe et XVIIIe siècles, et incarnent chacun une voix des Lumières. L’aveugle, au prisme de sa cécité, produit une critique de la société d’Ancien Régime hiérarchisée et inégalitaire, en tant qu’elle est fondée sur le sens de la vue

Neuroimaging and Pathology Biomarkers in Parkinson's Disease and Parkinsonism

International audienceThe "Neuroimaging and Pathology Biomarkers in Parkinson's Disease" course held on 12-13 September 2025 in Milan, Italy, convened an international faculty to review state-ofthe-art biomarkers spanning neurotransmitter dysfunction, protein pathology and clinical translation. Here, we synthesize the four themed sessions and highlights convergent messages for diagnosis, stratification and trial design. The first session focused on neuroimaging markers of neurotransmitter dysfunction, highlighting how positron emission tomography (PET), single photon emission computed tomography (SPECT), and magnetic resonance imaging (MRI) provided complementary insights into dopaminergic, noradrenergic, cholinergic and serotonergic dysfunction. The second session addressed in vivo imaging of protein pathology, presenting recent advances in PET ligands targeting αsynuclein, progress in four-repeat tau imaging for progressive supranuclear palsy and corticobasal syndromes, and the prognostic relevance of amyloid imaging in the context of mixed pathologies. Imaging of neuroinflammation captures inflammatory processes in vivo and helps study pathophysiological effects. The third session bridged pathology and disease mechanisms, covering the biology of α-synuclein and emerging therapeutic strategies, the clinical potential of seed amplification assays and skin biopsy, the impact of co-pathologies on disease expression, and the "brain-first" versus "body-first" model of pathological spread. Finally, the fourth session addressed disease progression and clinical translation, focusing on imaging predictors of phenoconversion from prodromal to clinically overt stages of synucleinopathies, concepts of neural reserve and compensation, imaging correlates of cognitive impairment, and MRI approaches for atypical parkinsonism. Biomarker-informed pharmacological, infusion-based, and surgical strategies, including network-guided and adaptive deep brain stimulation, were discussed as examples of how multimodal biomarkers may inform personalized management. Across all sessions, the need for harmonization, longitudinal validation, and pathology-confirmed outcome mea

Corporate social responsibility as a signal in the labor market

International audienceWorking for a firm engaged in Corporate Social Responsibility (CSR) appeals to potential workers by boosting their self-image and sense of purpose. We propose an additional mechanism: CSR signals a firm's future treatment of workers. Our model links CSR engagement with a firm's propensity to support workers during unforeseen times of need. Under this assumption, a potential future need of the worker leads to more firms engaging in CSR and to a higher workers' willingness to accept lower wages. Our experiment manipulates potential future needs across treatments. While the aggregate analysis does not fully support our theory, exploratory analysis reveals that male workers respond as predicted, whereas female workers do not. Consistently, in a risky environment, male employers increase their CSR engagement, which raises the acceptance rate among male workers. These results do not hold for female employers and workers.</div

Embodied speech: Sensorimotor contributions to native and non-native phoneme processing and learning

International audienceLearning to recognize and produce foreign speech sounds can be challenging, particularly when only subtle differences distinguish these new sounds from phonemes in the native language. Functional neuroimaging evidence shows that the motor cortex is involved in speech production and in perceptual phonemic processing. This highlights the embodied nature of speech perception, predicting the potential benefits of sensorimotor-based training approaches to enhance the acquisition of foreign speech sounds. Hence, here we first review current findings on the motor contribution to not only native but also non-native phoneme perception. Available evidence has established that motor cortical activity especially shows up under non-optimal perceptual conditions, such as when native phonemes are degraded by noise or when listeners perceive non-native speech sounds. Drawing upon this evidence, we then review training paradigms that have been developed for learning foreign phonemes, with a special emphasis on those embedding manual gestures as cues to represent phonetic features of the to-be-learned speech sounds. By pointing to both strengths and caveats of available studies, this review allows to delineate a clear framework and opens perspectives to optimize foreign phoneme learning, and ultimately support perception and production.</div

Existence and Regularity of Minimizers for a Plateau Approximation Problem

In this paper, we study the functional introduced by the author in collaboration with Bonnivard, Bretin, and Lemenant, which is designed to approximate Plateau’s problem. We establish the existence of a minimizer and prove its Hölder regularity. Our results may be viewed as a generalization to higher-dimensional surfaces of the one-dimensional work of Bonnivard, Lemenant, and Millot on the approximation of the Steiner problem

CCASL: Counterexamples to comparative analysis of scientific literature—Application to polymers

International audienceThe exponential growth of scientific publications has made the exploration and comparative analysis of scientific literature increasingly complex. For instance, identifying pairs of publications that diverge on widely accepted concepts within a domain is extremely difficult, if not impossible, at a large scale. Our work aims to automatically detect such discrepancies using recent artificial intelligence techniques. Given a particular scientific domain, we propose to capture domain knowledge through the definition of arbitrary functions expressed as relaxed functional dependencies (RFDs), and then focus on the large-scale analysis of tables in the publications related to these RFDs. In this context, we propose a four-step method called Counterexamples to Comparative Analysis of Scientific Literature (CCASL), which consists of the following steps: (1) Modeling the domain knowledge with functions expressed as RFDs, (2) Acquiring a corpus of related publications, (3) Analyzing all tables in the PDF documents and producing a consolidated table, (4) Detecting counterexamples of the RFDs in the consolidated table and conducting a comparative analysis of the pairs of papers containing the detected counterexamples. We have applied CCASL to a subfield of polymer research by identifying an arbitrary function relating the storage modulus, the polymer structure, and the glass transition temperature. Based on this function, we implemented the four steps of CCASL for largescale bibliographic confrontation in polymer science, which enabled us to detect several counterexamples. After detailed analysis, these counterexamples were found to originate from two main sources: typographical errors and methodological inconsistencies. The latter led to an update of the initial arbitrary function, specifying that it is valid only for fully reacted mixtures