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Congruences for hook lengths of partitions
No full text14 pages, all comments are welcome ! arXiv admin note: text overlap with arXiv:2107.06793International audienceRecently, Amdeberhan et al. proved congruences for the number of hooks of fixed even length among the set of self-conjugate partitions of an integer , therefore answering positively a conjecture raised by Ballantine et al.. In this paper, we show how these congruences can be immediately derived and generalized from an addition theorem for self-conjugate partitions proved by the second author. We also recall how the addition theorem proved before by Han and Ji can be used to derive similar congruences for the whole set of partitions, which are originally due to Bessenrodt, and Bacher and Manivel. Finally, we extend such congruences to the set of -asymmetric partitions defined by Ayyer and Kumari, by proving an addition-multiplication theorem for these partitions. Among other things, this contains as special cases the congruences for the number of hook lengths for the self-conjugate and the so-called doubled distinct partitions
CytoSyn: a Foundation Diffusion Model for Histopathology - Tech Report
No full textComputational pathology has made significant progress in recent years, fueling advances in both fundamental disease understanding and clinically ready tools. This evolution is driven by the availability of large amounts of digitized slides and specialized deep learning methods and models. Multiple self-supervised foundation feature extractors have been developed, enabling downstream predictive applications from cell segmentation to tumor sub-typing and survival analysis. In contrast, generative foundation models designed specifically for histopathology remain scarce. Such models could address tasks that are beyond the capabilities of feature extractors, such as virtual staining. In this paper, we introduce CytoSyn, a state-of-the-art foundation latent diffusion model that enables the guided generation of highly realistic and diverse histopathology H&E-stained images, as shown in an extensive benchmark. We explored methodological improvements, training set scaling, sampling strategies and slide-level overfitting, culminating in the improved CytoSyn-v2, and compared our work to PixCell, a state-of-the-art model, in an in-depth manner. This comparison highlighted the strong sensitivity of both diffusion models and performance metrics to preprocessing-specific details such as JPEG compression. Our model has been trained on a dataset obtained from more than 10,000 TCGA diagnostic whole-slide images of 32 different cancer types. Despite being trained only on oncology slides, it maintains state-of-the-art performance generating inflammatory bowel disease images. To support the research community, we publicly release CytoSyn's weights, its training and validation datasets, and a sample of synthetic images in this repository: https://huggingface.co/Owkin-Bioptimus/CytoSyn.</div
Deepest voting on rankings
No full textThis article aims to present a unified framework for ranking-based voting rules based on the use of depth functions on permutations, as a counterpart of deepest voting rules on evaluation introduced in Aubin et al. [2022]. It introduces the notion of depth functions, in continuous sets and in permutation sets, the later using the notion of Fréchet means. Deepest voting procedures are then formally defined, and some classical voting rules are expressed as deepest voting procedures, using a large variety of distances on the set of permutations. Links are done between the depth functions mathematical properties and some behaviours of the voting rule, such as Neutrality, Anonymity, Universality, Condorcet winner/loser property and so on
Rejecting Arguments Based on Doubt in Structured Bipolar Argumentation
No full textInternational audienceThis paper develops a new approach to computational argumentation that is informed by philosophical and linguistic views. Namely, it takes into account two ideas that have received little attention in the literature on computational argumentation: First, an agent may rationally reject an argument based on mere doubt, thus not all arguments they could defend must be accepted; and, second, that it is sometimes more natural to think in terms of which individual sentences or claims an agent accepts in a debate, rather than which arguments. In order to incorporate these two ideas into a computational approach, we first define the notion of structured bipolar argumentation frameworks (SBAFs), where arguments consist of sentences and we have both an attack and a support relation between them. Then, we provide semantics for SBAFs with two features: (1) Unlike with completeness-based semantics, our semantics do not force agents to accept all defended arguments. (2) In addition to argument extensions, which give acceptable sets of arguments, we also provide semantics for language extensions that specify acceptable sets of sentences. These semantics represent reasonable positions an agent might have in a debate. Our semantics lie between the admissible and complete semantics of abstract argumentation. Further, our approach can be used to provide a new perspective on existing approaches. For instance, we can specify the conditions under which an agent can ignore support between arguments (i.e. under which the use of abstract argumentation is warranted) and we show that deductive support semantics is a special case of our approach
Comment les choix de design d'interface mène à des effets environnementaux indirects par l'intensification des usages: Une évaluation environnementale empirique des applications de messagerie
No full textInternational audienceIn sustainable HCI, the 'Cornucopian Paradigm' describes how the expansion of digital services goes hand in hand with the growth of digital infrastructure and its environmental footprint. Yet, the mechanisms driving this paradigm are not well understood at the design level. As a case study, we investigate how messaging apps factor in the cornucopian paradigm by conducting a feature analysis of 17 apps complemented with 12 user interviews. We identify four scale-up mechanisms that explain how design contributes to the cornucopian paradigm. These mechanisms all contribute to use intensification, i.e., digital practices becoming more intensive and leading to more data intensity, to infrastructure expansion, and indirectly to device obsolescence and replacement. Our analysis of use intensification builds upon a set of recurring cornucopian design patterns we identified in messaging apps. To mitigate the cornucopian paradigm, we propose a set of moderation heuristics to guide design decisions.Dans le champ de l'IHM soutenable (SHCI), le « paradigme de la corne d'abondance » décrit comment l'expansion des services numériques s'accompagne de l'expansion des infrastructures numériques et de leur impact environnemental. Pourtant, les mécanismes sous-jacents à ce paradigme restent mal compris au niveau du design. À titre d'étude de cas, nous analysons comment les applications de messagerie s'intègrent à ce paradigme en réalisant une analyse des fonctionnalités de 17 applications, complétée par 12 entretiens utilisateurs. Nous identifions quatre mécanismes d'accroissement qui expliquent comment le design contribue au paradigme de la corne d'abondance. Ces mécanismes contribuent tous à l'intensification des usages (quand les pratiques numériques deviennent plus intensives, entraînant une augmentation du volume de données), à l'expansion des infrastructures et, indirectement, à l'obsolescence et au remplacement des appareils. Notre analyse de l'intensification des usages s'appuie sur un ensemble de design patterns récurrents liés au paradigme de la corne d'abondance, que nous avons identifiés dans les applications de messagerie. Afin d'atténuer les effets de ce paradigme, nous proposons un ensemble d'heuristiques de modération pour guider les décisions de design numérique
Transfer of generalized amalgamation in simple theories
No full textWe give an abstract framework to transfer generalized amalgamation from a simple theory to another, and we apply it to theories of lovely pairs and of bounded PAC structures. We show in particular that bounded pseudo-algebraically closed fields have generalized amalgamation, regardless of their imperfection degree
Discrétisation de milieux multicouches à forts contrastes : qu'en est-il des interfaces ?
No full textWave propagation in multilayered media with high material contrasts poses significant numerical challenges, as large variations in wavenumbers lead to strong reflections and complex transmission of the incoming wave field. To address these difficulties, we employ a boundary integral formulation thereby avoiding volumetric discretization. In this framework, the accuracy of the numerical solution depends strongly on how the material interfaces are discretized. In this work, we demonstrate that standard meshing strategies based on resolving the maximum wavenumber across the domain become computationally inefficient in multilayered configurations, where high wavenumbers are confined to localized subdomains. Through a systematic study of multilayer transmission problems, we show that no simple discretization rule based on the maximum wavenumber or material contrasts emerges. Instead, the wavenumber of the background (exterior) medium plays a dominant role in determining the optimal boundary resolution. Building on these insights, we propose an adaptive approach that achieves uniform accuracy and efficient computation across multiple layers. Numerical experiments for a range of multilayer configurations demonstrate the scalability and robustness of the proposed approach
Automatic Physically-Based Sim2Real for Tactile Images through Differentiable Path-Tracing Rendering
No full textInternational audienceHigh-fidelity simulation of vision-based tactile sensors is essential for developing data-driven robotic manipulation algorithms. However, a significant sim-to-real gap persists due to the difficulty in modeling complex optical effects, such as refraction through protective glass layers, and in accurately estimating physical parameters like sensor pose and lighting. To bridge this gap, we introduce a novel, fully differentiable pipeline for visual tactile simulation. Leveraging a differentiable path tracer, our method optimizes critical parameters—including camera pose, lighting conditions, and object texture—directly from just three real images. This approach achieves highly realistic simulations with physically accurate light transport and glass refraction. We validate our method through a comprehensive benchmark against real-world data, demonstrating state-of-the-art sim-to-real accuracy. We also enable novel applications, such as mesh reconstruction from a single tactile image via inverse rendering. To overcome the computational cost of path tracing, we further use a image-to-image translation model. This model uses high-fidelity simulated data alongside Normalized Object Coordinate Space (NOCS) maps as input, preserving crucial deformation information while enabling rapid inference
Electroporation of spheroids using an electric field gradient: a tool to study intensity-dependent permeabilization
No full textInternational audienceElectroporation (EPN) is the process by which cell membranes become transiently or permanently permeable upon exposure to pulsed electric fields of suitable intensity and duration. Depending on the pulse parameters, permeabilization can be reversible or irreversible, enabling a wide range of biomedical applications. To improve our understanding of EPN effects on tissues and select efficient treatments and parameters, relevant in vitro tumour models are required. Three-dimensional (3D) cell spheroids have emerged as valuable systems, as they more accurately replicate tumour microenvironment and cell-to-cell interactions than conventional 2D cultures. In this work, we present a new microdevice designed for the culture and gradual electroporation of a population of several hundred uniformly sized spheroids, allowing the systematic study of electroporation over a wide range of electric field intensities within a single experiment. Gradual permeabilization of HT-29 colorectal cancer cell spheroids was performed using a standard electrochemotherapy protocol, and electroporation efficiency was assessed by analysing propidium iodide (PI) uptake. Spheroids were treated with electric fields ranging from 800 V cm−1 to 3400 V cm−1. In toto analysis of PI distribution within spheroids by confocal microscopy revealed highly heterogeneous permeabilization patterns throughout the spheroid volume, for all intensities investigated, even at the highest one of 3400 V cm−1. This study introduces a robust 3D in vitro assay for the systematic evaluation of electroporation-based treatments, providing new insights into the influence of electric field heterogeneity, electrical protocol, and estimation of molecular uptake in the spheroid volume
Encyclopedia2GeoKG : un outil pour l'extraction d'informations et la génération de graphes de connaissances géo-historiques à partir d'articles encyclopédiques
No full textNational audienceLes dictionnaires et encyclopédies anciennes, comme celle de Diderot et d'Alembert (1751-1772), renferment des connaissances, notamment géographiques, qui sont précieuses pour étudier leur évolution au cours des derniers siècles. Les milliers d'articles dans ces oeuvres nécessitent cependant des outils automatisés pour extraire des informations fiables et structurées. Notre outil s'appuie sur des modèles entraînés spécifiquement pour les textes anciens et permet de construire un graphe RDF représentant les entités géographiques et leurs relations spatiales. Un prototype interactif de l'outil ainsi que les modèles sont disponibles sur HuggingFace, le code est disponible sur gitla