47 research outputs found

    The combinatorics of plane curve singularities. How Newton polygons blossom into lotuses

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    This survey may be seen as an introduction to the use of toric and tropical geometry in the analysis of plane curve singularities, which are germs (C,o)(C,o) of complex analytic curves contained in a smooth complex analytic surface SS. The embedded topological type of such a pair (S,C)(S, C) is usually defined to be that of the oriented link obtained by intersecting CC with a sufficiently small oriented Euclidean sphere centered at the point oo, defined once a system of local coordinates (x,y)(x,y) was chosen on the germ (S,o)(S,o). If one works more generally over an arbitrary algebraically closed field of characteristic zero, one speaks instead of the combinatorial type of (S,C)(S, C). One may define it by looking either at the Newton-Puiseux series associated to CC relative to a generic local coordinate system (x,y)(x,y), or at the set of infinitely near points which have to be blown up in order to get the minimal embedded resolution of the germ (C,o)(C,o) or, thirdly, at the preimage of this germ by the resolution. Each point of view leads to a different encoding of the combinatorial type by a decorated tree: an Eggers-Wall tree, an Enriques diagram, or a weighted dual graph. The three trees contain the same information, which in the complex setting is equivalent to the knowledge of the embedded topological type. There are known algorithms for transforming one tree into another. In this paper we explain how a special type of two-dimensional simplicial complex called a lotus allows to think geometrically about the relations between the three types of trees. Namely, all of them embed in a natural lotus, their numerical decorations appearing as invariants of it. This lotus is constructed from the finite set of Newton polygons created during any process of resolution of (C,o)(C,o) by successive toric modifications.Comment: 104 pages, 58 figures. Compared to the previous version, section 2 is new. The historical information, contained before in subsection 6.2, is distributed now throughout the paper in the subsections called "Historical comments''. More details are also added at various places of the paper. To appear in the Handbook of Geometry and Topology of Singularities I, Springer, 202

    Écriture et transmission des savoirs de l’AntiquitĂ© Ă  nos jours

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    Pendant longtemps, la transmission des savoirs s’est faite directement, du maĂźtre Ă  l’élĂšve, de l’artisan Ă  l’apprenti, par un enseignement oral que venait complĂ©ter la dĂ©monstration des gestes de la pratique. L’apparition de l’écriture, et plus encore la diffusion de la literacy ont fait que des mĂ©thodes de transmission indirectes ont pu se faire jour et que l’acquisition d’un savoir, quel qu’il soit, a pu se faire sans contact immĂ©diat avec le dĂ©tenteur de ce savoir, mais par le truchement d’un livre ou d’une autre forme d’écrit. Il s’est ensuivi une capacitĂ© de diffusion des savoirs quasiment illimitĂ©e, des plus techniques et spĂ©cialisĂ©s aux plus abstraits et gĂ©nĂ©ralistes. C’est cette explosion de la transmission des savoirs que les vingt auteurs des contributions ici rĂ©unies ont cherchĂ© Ă  explorer en mettant en lumiĂšre diffĂ©rentes facettes, Ă  travers une sĂ©rie d’exemples, allant de l’AntiquitĂ© Ă  l’époque contemporaine. Le CongrĂšs national des sociĂ©tĂ©s historiques et scientifiques rassemble chaque annĂ©e universitaires, membres de sociĂ©tĂ©s savantes et jeunes chercheurs. Ce recueil est issu de travaux prĂ©sentĂ©s lors du 143e CongrĂšs sur le thĂšme « La transmission des savoirs »

    The Athena X-ray Integral Field Unit: a consolidated design for the system requirement review of the preliminary definition phase

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    The Athena X-ray Integral Unit (X-IFU) is the high resolution X-ray spectrometer, studied since 2015 for flying in the mid-30s on the Athena space X-ray Observatory, a versatile observatory designed to address the Hot and Energetic Universe science theme, selected in November 2013 by the Survey Science Committee. Based on a large format array of Transition Edge Sensors (TES), it aims to provide spatially resolved X-ray spectroscopy, with a spectral resolution of 2.5 eV (up to 7 keV) over an hexagonal field of view of 5 arc minutes (equivalent diameter). The X-IFU entered its System Requirement Review (SRR) in June 2022, at about the same time when ESA called for an overall X-IFU redesign (including the X-IFU cryostat and the cooling chain), due to an unanticipated cost overrun of Athena. In this paper, after illustrating the breakthrough capabilities of the X-IFU, we describe the instrument as presented at its SRR, browsing through all the subsystems and associated requirements. We then show the instrument budgets, with a particular emphasis on the anticipated budgets of some of its key performance parameters. Finally we briefly discuss on the ongoing key technology demonstration activities, the calibration and the activities foreseen in the X-IFU Instrument Science Center, and touch on communication and outreach activities, the consortium organisation, and finally on the life cycle assessment of X-IFU aiming at minimising the environmental footprint, associated with the development of the instrument. Thanks to the studies conducted so far on X-IFU, it is expected that along the design-to-cost exercise requested by ESA, the X-IFU will maintain flagship capabilities in spatially resolved high resolution X-ray spectroscopy, enabling most of the original X-IFU related scientific objectives of the Athena mission to be retained. (abridged).Comment: 48 pages, 29 figures, Accepted for publication in Experimental Astronomy with minor editin

    The Athena X-ray Integral Field Unit: a consolidated design for the system requirement review of the preliminary definition phase

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    The Athena X-ray Integral Unit (X-IFU) is the high resolution X-ray spectrometer studied since 2015 for flying in the mid-30s on the Athena space X-ray Observatory. Athena is a versatile observatory designed to address the Hot and Energetic Universe science theme, as selected in November 2013 by the Survey Science Committee. Based on a large format array of Transition Edge Sensors (TES), X-IFU aims to provide spatially resolved X-ray spectroscopy, with a spectral resolution of 2.5 eV (up to 7 keV) over a hexagonal field of view of 5 arc minutes (equivalent diameter). The X-IFU entered its System Requirement Review (SRR) in June 2022, at about the same time when ESA called for an overall X-IFU redesign (including the X-IFU cryostat and the cooling chain), due to an unanticipated cost overrun of Athena. In this paper, after illustrating the breakthrough capabilities of the X-IFU, we describe the instrument as presented at its SRR (i.e. in the course of its preliminary definition phase, so-called B1), browsing through all the subsystems and associated requirements. We then show the instrument budgets, with a particular emphasis on the anticipated budgets of some of its key performance parameters, such as the instrument efficiency, spectral resolution, energy scale knowledge, count rate capability, non X-ray background and target of opportunity efficiency. Finally, we briefly discuss the ongoing key technology demonstration activities, the calibration and the activities foreseen in the X-IFU Instrument Science Center, touch on communication and outreach activities, the consortium organisation and the life cycle assessment of X-IFU aiming at minimising the environmental footprint, associated with the development of the instrument. Thanks to the studies conducted so far on X-IFU, it is expected that along the design-to-cost exercise requested by ESA, the X-IFU will maintain flagship capabilities in spatially resolved high resolution X-ray spectroscopy, enabling most of the original X-IFU related scientific objectives of the Athena mission to be retained. The X-IFU will be provided by an international consortium led by France, The Netherlands and Italy, with ESA member state contributions from Belgium, Czech Republic, Finland, Germany, Poland, Spain, Switzerland, with additional contributions from the United States and Japan.The French contribution to X-IFU is funded by CNES, CNRS and CEA. This work has been also supported by ASI (Italian Space Agency) through the Contract 2019-27-HH.0, and by the ESA (European Space Agency) Core Technology Program (CTP) Contract No. 4000114932/15/NL/BW and the AREMBES - ESA CTP No.4000116655/16/NL/BW. This publication is part of grant RTI2018-096686-B-C21 funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe”. This publication is part of grant RTI2018-096686-B-C21 and PID2020-115325GB-C31 funded by MCIN/AEI/10.13039/501100011033

    The FANCM:p.Arg658* truncating variant is associated with risk of triple-negative breast cancer

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    Abstract: Breast cancer is a common disease partially caused by genetic risk factors. Germline pathogenic variants in DNA repair genes BRCA1, BRCA2, PALB2, ATM, and CHEK2 are associated with breast cancer risk. FANCM, which encodes for a DNA translocase, has been proposed as a breast cancer predisposition gene, with greater effects for the ER-negative and triple-negative breast cancer (TNBC) subtypes. We tested the three recurrent protein-truncating variants FANCM:p.Arg658*, p.Gln1701*, and p.Arg1931* for association with breast cancer risk in 67,112 cases, 53,766 controls, and 26,662 carriers of pathogenic variants of BRCA1 or BRCA2. These three variants were also studied functionally by measuring survival and chromosome fragility in FANCM−/− patient-derived immortalized fibroblasts treated with diepoxybutane or olaparib. We observed that FANCM:p.Arg658* was associated with increased risk of ER-negative disease and TNBC (OR = 2.44, P = 0.034 and OR = 3.79; P = 0.009, respectively). In a country-restricted analysis, we confirmed the associations detected for FANCM:p.Arg658* and found that also FANCM:p.Arg1931* was associated with ER-negative breast cancer risk (OR = 1.96; P = 0.006). The functional results indicated that all three variants were deleterious affecting cell survival and chromosome stability with FANCM:p.Arg658* causing more severe phenotypes. In conclusion, we confirmed that the two rare FANCM deleterious variants p.Arg658* and p.Arg1931* are risk factors for ER-negative and TNBC subtypes. Overall our data suggest that the effect of truncating variants on breast cancer risk may depend on their position in the gene. Cell sensitivity to olaparib exposure, identifies a possible therapeutic option to treat FANCM-associated tumors

    A case-only study to identify genetic modifiers of breast cancer risk for BRCA1/BRCA2 mutation carriers

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    Abstract: Breast cancer (BC) risk for BRCA1 and BRCA2 mutation carriers varies by genetic and familial factors. About 50 common variants have been shown to modify BC risk for mutation carriers. All but three, were identified in general population studies. Other mutation carrier-specific susceptibility variants may exist but studies of mutation carriers have so far been underpowered. We conduct a novel case-only genome-wide association study comparing genotype frequencies between 60,212 general population BC cases and 13,007 cases with BRCA1 or BRCA2 mutations. We identify robust novel associations for 2 variants with BC for BRCA1 and 3 for BRCA2 mutation carriers, P < 10−8, at 5 loci, which are not associated with risk in the general population. They include rs60882887 at 11p11.2 where MADD, SP11 and EIF1, genes previously implicated in BC biology, are predicted as potential targets. These findings will contribute towards customising BC polygenic risk scores for BRCA1 and BRCA2 mutation carriers

    Integrated platform for home services using new products and services for senior citizens Call CNAV-CARSAT 2015.

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    International audienceThis project is part of: i) the risks of ageing prevention policy of the French retirement and occupational health insurance agency of Languedoc Roussillon (Carsat-LR) and ii) the European innovation partnership on active and healthy ageing (EIP on AHA). It aims to support senior citizens who live independently and have been identified at risk of frailty on a social or health level. The purpose is to increase legibility as well as technical and financial access to innovations for vulnerable seniors who are remote from the digital era, through a multiservice user-friendly platform. Launched at the end of 2015, the project rallies over 10 actors of the silver economy currently developing personalised ICT tools to improve the safety and comfort of seniors and the coordination between health and social care. The objective is threefold: i) developing new adapted technologies, ii) having them evaluated by retirees and professionals and iii) making them accessible to the ICT web platform which will provide tutorials and prices and collect opinions from users and professionals. 500 retirees selected by CARSAT-LR will be testing these new devices and solutions which will be provided without charge. The following will be evaluated: i) feedback from users; ii) benefits gained through accessing comprehensive and appropriate information; iii) coordination of caregivers and professionals; iv) enjoyment from using the products (access to games, social links, customer confidence, sense of safety). This is a unique opportunity to mobilise solutions in a structured manner, bringing together competing businesses under a consortium agreement. Advantages for these businesses include acceleration of development and availability of their adapted solutions as well as the possibility to test their products on a significant panel of people. Professional caregiver's data follow-up will identify seniors at risk of frailty, proposing preventive actions and local services tailored to their needs
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