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Data Beyond Control
No full textInternational audienceIn a context of increasing digitalization, controlling data flows constitutes a major challenge for organizations, particularly when it comes to sensitive data. This study examines the technical and legal challenges related to secure data flow management, based on the concrete case of the medical analysis laboratory MedLab and its facial recognition system implementation project. The study proposes an integrated approach combining Zero-Trust architecture, multi-factor authentication mechanisms, and advanced encryption solutions, while ensuring compliance with GDPR and other applicable regulations. Special attention is paid to subcontractor management and international data transfers. The results demonstrate that a holistic approach, combining innovative technical solutions and robust governance, can effectively meet security and compliance requirements. The study also emphasizes the importance of continuous adaptation to technological and regulatory developments, offering concrete recommendations for organizations wishing to strengthen control of their data flows
NURBS grids for DG methods: a synthesis
No full textInternational audienceThis contribution aims at providing a sound synthesis of advantages and drawbacks of using Non-Uniform Rational B-Spline (NURBS) grids in the context of body-fitted Discontinuous Galerkin (DG) methods for compressible Euler / Navier-Stokes equations. This approach has the capability of representing exactly Computer-Aided Design (CAD) geometries, yielding an improved solution accuracy in the vicinity of curved boundaries. Moreover, the geometrical properties of the NURBS representation allow elegant and efficient treatments of some problems, for instance involving sliding or deforming grids, local refinement, shape sensitivity analysis or transfer of data for multidisciplinary couplings. For all these problems, the benefits and limitations of NURBS are discussed, with the highlight of numerical experiments, and compared to alternative approaches (non body-fitted, isoparametric, etc.)
Outcome of 1773 superficial non-dermatofibrosarcoma sarcomas A French Sarcoma Group study (FSG) from the NETSARC database
No full textInternational audienceBackground: Clinical practice guidelines for managing superficial non-dermatofibrosarcoma soft tissue sarcomas (NDSTS) vary depending on surgical margins. This study assessed NDSTS outcomes by margin status and re-excision (RE) in the nationwide NETSARC+ database.Methods: This retrospective study (MR004-346) of 1773 patients used clinical data from the NETSARC database between 01/01/2010 and 12/30/2017. Analyses focused on local relapse-free survival (LRFS) and overall survival (OS).Results: Pre-surgery, 31 % of patients underwent local staging with imaging, 46 % biopsy, and 17.8 % a reference center multidisciplinary tumor board (MDTB). Initial margin quality was R0, R1, R2, and unknown for 37 %, 36 %, 13 %, and 12.8 % of patients respectively. Univariate analysis positively correlated R0 surgery with preoperative biopsy (p < 0.001), adequate local imaging for tumors ≥ 5 cm (p < 0.009), case discussion within a NETSARC+ MDTB (p < 0.001), and tumor size< 5 cm (p < 0.001). Reference network surgery resulted in higher proportions of R0 margins (p < 0.001). Re-excision (RE) was performed in 9.7 %, 63 %,79 %, and 34 % of patients following initial surgery with R0, R1, R2, and unknown margins, respectively. Multivariate analysis identified several poor LRFS prognostic factors: size ≥ 5 cm (HR=1.47, p = 0.002), angiosarcoma (HR=2.95, p < 0.001), surgery outside a NETSARC network (HR=1.61, p = 0.003), old age (p < 0.001), and no final R0 margin (HR=2.60, p < 0.001). Multivariate analysis identified several poor OS prognostic factors: angiosarcoma (HR=2.03, p = 0.065), trunk/head and neck site (HR=1.57, p = 0.004), grades 2 and 3 (respectively HR=2.21, p = 0.039 and HR=4.35, p < 0.001), age (p < 0.001), and no final R0 margins (HR=2.02, p < 0.001).Conclusion: Sarcoma clinical practice guideline compliance was associated with better surgery quality, reduced local relapse rates, and improved survival
Exploring the formation of multiple dust-trapping rings in the inner Solar System
No full textInternational audienceContext. Isotopic properties of meteorites provide evidence that multiple dust trap or pressure bumps had to form and persist in the inner Solar System on a timescale of millions of years. The formation of a pressure bump at the outer edge of the gap opened by Jupiter would be effective in blocking particles drifting from the outer to the inner disc. Yet this would not be enough to preserve dust in the inner disc. However, in low-viscosity discs and under specific conditions governing the gas cooling time, it has been shown that massive planets can also open secondary gaps, separated by density bumps, inwards of the main gap. The majority of studies of the process of secondary gap formation have been done in two dimensional equatorial simulations with prescribed disc cooling or by approximating the cooling from the disc photosphere. Recent results have shown that an appropriate computation of the disc cooling by including the treatment of radiation transport is key to determining the formation of secondary gaps.Aims. Our aim is to extend previous studies to three dimensional discs by also including radiative effects. Moreover, we also consider non-ideal magnetohydrodynamic effects in discs with a prescribed cooling time to explore the feedback of the magnetic field on secondary gap formation.Methods. We performed three dimensional hydrodynamical numerical simulations with a self-consistent treatment of radiative effects making use of a flux-limited diffusion approximation. We then extended our study to a similar disc including the magnetic field and non-ideal Ohmic and ambipolar effects.Results. We show that in the hydrodynamical model, a disc with low bulk viscosity (αν = 10−4) and consistent treatment of radiative effects, a Jupiter-mass planet is capable of opening multiple gaps. We also show that multiple gaps and rings are formed by planetary masses close to the pebble isolation mass. In the presence of non-ideal MHD effects, multiple gaps and rings are also formed by a Jupiter-mass planet.Conclusions. A solid Jupiter core in low-viscosity discs blocks particles drifting towards and within the inner disc. The formation of multiple gaps and rings inside the planetary orbit at this stage is crucial to preserving dust reservoirs. Such reservoirs are pushed towards the inner part of the disc during Jupiter runaway growth and they are shown to be persistent after Jupiter’s growth. Multiple dust reservoirs could therefore be present in the inner Solar System since the formation of Jupiter’s solid core when the disc is characterised by low viscosity
Des collèges sous tension autour de la prise en charge des exclusions par les assistants d’éducation
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Les effets trans-formatifs de formations universitaires auprès de professionnel.le.s des métiers de la relation
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Quantifying Miocene thin- and thick-skinned shortening in the Baous thrust system, SW French Alpine Front
No full textInternational audienceAt the southernmost front of the southwestern French Alps, the Baous thrust system is a key marker of Alpine deformation. Based on detailed surface data and a balanced, sequentially restored cross-section, this study shows that the SSW-verging Baous thrust is rooted in a deep-seated basement thrust, kinematically linked to shallower thrusts detached within Triassic evaporites. This basement thrust reactivates an inherited, north-dipping Jurassic extensional fault, which controls the development of the Saint-Barnabé anticline in the north. To the south, the Courmettes structures display fault-bend fold geometries and associated shortcut thrusts. Restoration constrains a total horizontal shortening of 5 km (31.4 %), partitioned between the sedimentary cover (43 %, ~2.1 km) and the basement (57 %, ~2.9 km), reflecting both thin- and thick-skinned tectonics. The Courmettes-Vence syn-tectonic basin, located in the footwall, provides key temporal constraints on thrust development. Six deformation stages, identified through sequential restoration between the Burdigalian and Messinian, highlight increasing shortening rates: 0.17 km/Myr (Burdigalian-Tortonian), 0.37 km/Myr (Tortonian), and 1.16 km/Myr (Messinian). Kinematic relationships indicate a primarily in-sequence deformation propagation toward the Alpine foreland: initial basement-involved thrusting was followed by activation of thin-skinned thrusts, then overprinted by out-of-sequence reactivation of the basement thrust. The proposed kinematic model is consistent with recent onshore and offshore seismic interpretations, supporting its robustness and relevance for understanding the tectonic evolution of the southwestern Alpine front. These results emphasize the role of inherited extensional structures (here Jurassic in age) in shaping fold-and-thrust belts and controlling thrust geometry, deformation style, and present-day distribution of seismicity
Une approche contructive des slices de Seshadri pour calculer des invariants séparants
No full textThe aim of this thesis is to formulate new methods for computing separating invariants for a representation of an algebraic group, i.e., functions that are invariant under the action of the group and take different values on distinct orbits. The main idea is to refine Seshadri’s lemma, as formulated in [CS05], for constructive purposes. This lemma gives an isomorphism by restriction between the field of invariants of the representation and the field of invariants for the representation of a normalizer on a submanifold. It has been mainly used for theoretical purposes, such as proving the rationality of invariant fields. However, the isomorphism already allows, at first glance, the construction of a set of rational invariants generating the field of invariants. This is equivalent to separating the orbits almost everywhere, which is a good first step. The method is implemented for the action of SO₃(ℝ) on the space of piezoelectric tensors, for which we present a first slice in the representations of the orthogonal group containing the standard representation. This yields a generic separating set of minimal cardinality 15. In a second step, we consider iterating this slice as far as possible, starting from an action of an orthogonal group SOₙ(ℝ) in higher dimension (n ≥ 3). The theory of representations of Lie groups allows us to describe the action of successive normalizers, of the form SOₖ(ℝ) ⋉ ℂ²ⁿ⁻ᵏ. We obtain a sufficient criterion for the rationality of the field of invariants of the actions of SOₙ(ℝ), as well as generic separators for the standard action on a family of vectors. The separators of these representations are particularly sought after for the training of invariant neural networks [DG24; BV23]. We then go further, aiming not at generic but at total separation (in the sense of the separating polynomial invariants defined in [Kem07]). As given, the isomorphism of the Seshadri slice induces singularities at unpredictable locations, making this task impossible. However, a strengthening of the hypotheses inspired by [Pop92] allows us to circumscribe the possible poles on an explicit submanifold Q. By finding another slice on Q, and iterating accordingly, we propose a method that yields a system of polynomial invariants that ultimately separates the orbits everywhere. This method applies particularly well to the representation of SO₃(ℝ) on the space of piezoelectric tensors, for which we provide a separating system of 102 invariants—very competitive compared to previous approaches. This second point required constructing separating invariants for the action of a normalizer O₂(ℂ) ≃ ℂ* ⋉ ℂ². The study of representations of complex tori thus emerged as a promising direction. Using the Chinese remainder theorem, we first treat the case of actions of the torus of rank one. Then, we generalize this theorem to dimension d, obtaining rational separating invariants whose support is of size bounded by d + 1. This yields a separating set of size polynomial in the dimension of the representation (precisely in dim(V)^(d+1)), providing partial answers to an open problem posed in [Gar+19].L’objectif de cette thèse est de formuler de nouvelles méthodes de calcul d’invariants séparants pour une représentation d’un groupe algébrique, c’est-à-dire des fonctions invariantes par l’action du groupe et prenant des valeurs différentes sur des orbites distinctes. L’idée principale est de raffiner le lemme de Seshadri tel que formulé dans [CS05] à des fins constructives. Ce lemme donne un isomorphisme par restriction entre le corps des invariants de la représentation, et le corps des invariants pour la représentation d’un normalisateur sur une sous-variété. Il a été principalement utilisé à des fins théoriques, comme pour prouver la rationalité des corps des invariants. Mais l’isomorphisme permet déjà, de prime abord, de construire un ensemble d’invariants rationnels générant le corps des invariants. Cela équivaut à séparer les orbites presque partout, ce qui représente un bon premier pas. La méthode est mise en œuvre pour l’action de SO₃(ℝ) sur l’espace des tenseurs piézoélectriques, pour lequel nous présentons une première slice dans les représentations du groupe orthogonal contenant la représentation standard. Cela donne un ensemble de séparants générique de cardinal minimal 15. En seconde instance, nous imaginons d’itérer cette slice autant que possible en partant d’une action d’un groupe orthogonal SOₙ(ℝ) en dimension plus grande (n ≥ 3). La théorie des représentations des groupes de Lie permet de décrire l’action des normalisateurs successifs, de la forme SOₖ(ℝ) ⋉ ℂ²ⁿ⁻ᵏ. On obtient un critère suffisant pour la rationalité du corps des invariants des actions de SOₙ(ℝ), ainsi que des séparants génériques pour l’action standard sur une famille de vecteurs. Les séparants de ces représentations étant particulièrement demandés pour l’entraînement de réseaux de neurones invariants [DG24 ; BV23]. Nous allons ensuite plus loin, visant non plus une séparation générique mais totale (dans le sens des invariants polynomiaux séparants définis dans [Kem07]). Donné tel quel, l’isomorphisme du slice de Seshadri induit des singularités en des lieux imprévisibles, rendant cette tâche impossible. Mais un renforcement des hypothèses inspiré par [Pop92] permet de circonscrire les pôles éventuels sur une sous-variété explicite Q. En trouvant une autre slice sur Q, et en itérant ainsi de suite, on propose une méthode donnant un système d’invariants polynomiaux séparant finalement les orbites partout. Cette méthode s’applique particulièrement bien à la représentation de SO₃(ℝ) sur l’espace des tenseurs piézoélectriques, pour lequel nous donnons un système séparateur de 102 invariants, ce qui est très compétitif par rapport à ce qui se faisait précédemment. Ce deuxième point a nécessité de donner des invariants séparants pour l’action d’un normalisateur O₂(ℂ) ≃ ℂ* ⋉ ℂ². L’étude des représentations des tores complexes s’est donc imposée comme une heureuse direction. À l’aide du théorème chinois, nous traitons d’abord le cas des actions du tore de rang un. Puis nous généralisons ce théorème en dimension d, obtenant des invariants rationnels séparants dont le support est de taille bornée par d + 1. Cela donne un ensemble de séparants de taille polynomiale en la dimension de la représentation (précisément en dim(V)^(d+1)), apportant des éléments de réponse à un problème posé dans [Gar+19]
Éléments de compréhension de nouvelles formes de soin : rapport d'expérience des tandems de partenariat médecin-patient partenaire en clinique
No full textSince 2022, an academic organization offering Art of Care in partnership with patients and the public in a systemic dimension (teaching, care, research, and popular education) has been supporting new care practices. This article aims to shed light on one of these new clinical practices, that of doctor-patient partnerships in clinical settings. According to authors from two different countries, this insight into care partnership tandems developed in both primary care and healthcare facilities provides relevant information about this new type of practice and offers an initial hypothesis about the context necessary for scaling up these new figures involved in care.Depuis 2022, une organisation académique proposant un Art du Soin en partenariat avec les patients et le public dans une dimension systémique (Enseignement, Soin, recherche et éducation populaire) accompagne de nouvelles pratiques de soin. Cet article propose d'éclairer un de ces nouveaux exercice en clinique, celui de tandems de partenariat médecin patient en milieu clinique. Cet éclairage de tandems de partenariat de soin développés tant en soins primaires qu'en établissement de santé permet selon les auteurs de deux pays différents, d'apporter des éléments de pertinence de ce nouveau type d'exercice et de poser une première hypothèse du contexte nécessaire à une mise à l'échelle de ces nouvelles figures impliquées dans le soin.</div
: From autobiographical memoirs to collective action: a “koino-biographical” model
No full textInternational audienceWhat a strange project it is for her to paint herself! One might think, with the memory of Pascal, when reading Zami, a text written by Audre Lorde with an undeniably autobiographical tone, the subtitle tipping the reading in this direction: ‘A New Spelling of My Name’. Audre Lorde calls it ‘biomythography’. The question of autobiography is shifted: Even if it recounts episodes, feelings and reflections, the text is not simply an account of one’s own existence; it goes beyond it to concern the women of one's own time and background, or those who have had similar experiences and want to finally speak out - as Simone de Beauvoir (Mémoires d'une jeune fille rangée, 1958), Maya Angelou (I Know Why the Caged Bird Sings, 1969...), Annie Ernaux (from Les Armoires vides, 1974, to Les Années, 2008), Assia Djebar (Nulle part dans la maison de mon père, 2007)... Ernaux refers to her work as ‘autosociography’. This writing is in itself militant, as bell hooks points out in Ain’t I a Woman? Black women and feminism (1981). More specifically, which grammatical ‘person’ to choose? How can a particular experience be transposed into a form that is useful to others? How can we create a community by sharing elements that a group will consider to be shared? In this sense, we might venture the neologism of ‘koino-biography’: an autobiography that is less individual than collective.Le drôle de projet qu’elle a de se peindre ! pourrait-on penser, avec le souvenir de Pascal, devant Zami, texte écrit par Audre Lorde avec une indéniable tonalité autobiographique, le sous-titre faisant pencher la lecture dans ce sens : « A New Spelling of My Name », « une nouvelle façon d’écrire mon nom ». Audre Lorde parle de « biomythographie ». La question de l’autobiographie est en effet décalée : même si elle raconte des épisodes, des ressentis, des réflexions, le texte n’est pas le simple récit de sa propre existence ; il la dépasse pour concerner les femmes de son époque et de son milieu, ou celles qui ont connu des expériences similaires et veulent enfin prendre la parole – comme l’ont fait de même par exemple Simone de Beauvoir (Mémoires d’une jeune fille rangée, 1958), Maya Angelou (I Know Why the Caged Bird Sings, 1969…), Annie Ernaux (depuis Les Armoires vides, 1974, jusqu’au texte Les Années, 2008)), Assia Djebar (Nulle part dans la maison de mon père, 2007)… Ernaux parle pour son œuvre d’« autosociographie ». Cette écriture est en soi militante, comme le souligne bell hooks dans Ain’t I a Woman ? Black women and feminism (1981). Plus particulièrement, quelle « personne » grammaticale choisir ? Comment transposer à une forme utile à d’autres une expérience particulière ? Comment créer une communauté par le partage d’éléments qu’un groupe va considérer comme partagés ? dans ce sens on peut risquer ce néologisme de « koino-biographie » : une autobiographie qui serait moins individuelle que collective