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Barium isotope cosmochemistry and geochemistry

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Science Bulletin 2018年第6期63卷 385-394页

作者： Quentin Charbonnier Frederic Moynier Julien Bouchez Institut de Physique du Globe de paris Universite Paris Diderot Sorbonne Paris Cite CNRS UMR 71541rue Jussieu 75238 Paris France Institut universitaire de France and universite paris diderot 75231 Paris France

While the isotopic variations of barium were reported for the first time fourty years ago, the number of studies on barium isotopes significantly increased only after 2010. Barium isotope anomalies in meteorites have been successfully used to provide constraints about the origin of presolar Si C grains. In carbonaceous chondrites Ba isotope anomalies are indicative of the heterogeneity of the early solar system, possibly resulting from of a later injection of material after the cooling of solar system. Barium isotope fractionation in the same carbonaceous chondrites suggests that a strong magnetic field was present in the innermost part of the early solar system. Barium mass-dependent isotope fractionation has also been detected throughout Earth surface materials. While igneous rocks show limited Ba isotopic variations, relatively large isotopic variations are observed amongst and within soils, rivers, and biological materials. Indeed, plants seem to fractionate Ba isotopes during Ba uptake from soil ***, Ba isotope signatures have the potential to provide clues on the biological cycling of Ba at the Earth surface. In seawater, Ba isotopic variations have been mapped out, and are mainly related to barite precipitation, which is in turn related to organic matter remineralization in the water *** makes Ba isotopes a potentially powerful tool to reconstruct past ocean productivity, although constraints are still lacking regarding the inputs of dissolved Ba to the oceans by rivers or hydrothermalism.

关键词： Barium Meteorites Earth surface Critical zone

Egg CD9 protein tides correlated with sperm oscillations tune the gamete fusion ability in mammal

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Journal of Molecular Cell Biology 2018年第6期10卷 494-502页

作者： Benjamin Ravaux Sophie Favier Eric Perez and Christine Gourier Laboratoire de Physique Statistique Ecole Normale Superieure/PSL Research UniversityUPMC Univ Paris 06Universite Paris DiderotCNRS75005 ParisFrance

Mammalian fertilization involves membrane events-adhesion,fusion,sperm engulfment,membrane block to polyspermy-whose causes remain largely ***,specific oscillations of the sperm in contact with the egg were shown to be necessary for *** a microfluidic chip to impose the venue for the encounter of two gametes allowed real-time observation of the membrane remodelling occurring at the sperm/egg *** spatiotemporal mapping of egg CD9 revealed that this protein concentrates at the egg/sperm interface as a result of sperm oscillations,until a CDg-rich platform is nucleated on which fusion immediately takes *** 2-5 min after fusion,most of the CD9 leaves the egg for the external aqueous *** an egg membrane wave engulfs the sperm head in^25 *** results show that sperm oscillations initiate the CD9 recruitment that causes gamete fusion after which CD9 and associated proteins leave the membrane in a process likely to contribute to block *** highlight that the gamete fusion story in mammals is an unexpected interplay between mechanical constraints and proteins.

关键词： mammalian fertilization membrane dynamics real-time imaging CDg sperm oscillations gamete fusion

A fully abstract semantics for value-passing CCS for trees

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Frontiers of Computer Science 2019年第4期13卷 828-849页

作者： Ying JIANG Shichao LIU Thomas EHRHARD State Key Laboratory of Computer Science Institute of Software Chinese Academy of Sciences Beijing 100190 China university of Chinese Academy of Sciences Beijing 100049 China CNRS IRIF UMR 8243 Univ Paris Diderot Sorbonne Paris Cite F-75205 Paris France

We propose a fully abstract semantics for valuepassing CCS for trees (VCCTS) with the feature that processes are located at the vertices of a graph whose edges describe possible interaction capabilities. The operational semantics is given both in terms of a reduction semantics and in terms of a labelled transition semantics. We develop a theory of behavioral equivalences by introducing both weak barbed congruence and weak bisimilarity. In particular, we show that, on image-finite processes, weak barbed congruence coincides with weak bisimilarity. To illustrate potential applications and the powerful expressiveness of VCCTS, we formally compare VCCTS with some well-known models, e.g., dynamic pushdown networks, top-down tree automata and value-passing CCS.

关键词： process calculus non-interleaving semantics barbed congruence bisimulation

Recovering Navier–Stokes Equations from Asymptotic Limits of the Boltzmann Gas Mixture Equation

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Communications in Theoretical Physics 2016年第5期65卷 553-562页

作者： Carlo Bianca Christian Dogbe Laboratoire de Physique Statistique Ecole Normale Superieure PSL Research University University Paris Diderot Sorbonne Paris-Cite Sorbonne Universites UPMC Univ Paris 06 CNRS Department of Mathematics Universite de Caen Normandie LMNOCNRS

This paper is devoted to the derivation of macroscopic fluid dynamics from the Boltzmann mesoscopic dynamics of a binary mixture of hard-sphere gas *** the hydrodynamics limit is performed by employing different time and space *** paper shows that,depending on the magnitude of the parameters which define the scaling,the macroscopic quantities(number density,mean velocity and local temperature)are solutions of the acoustic equation,the linear incompressible Euler equation and the incompressible Navier–Stokes *** derivation is formally tackled by the recent moment method proposed by[***,et al.,***.63(1991)323]and the results generalize the analysis performed in[***,et al.,*** ***.29(2015)240].

关键词： gas mixtures hydrodynamic limit asymptotic limit fluid equation conservation law

A Formal Passage From a System of Boltzmann Equations for Mixtures Towards a Vlasov-Euler System of Compressible Fluids

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Acta Mathematicae Applicatae Sinica 2019年第1期35卷 158-173页

作者： Laurent DESVILLETTES Fran?ois GOLSE Valeria RICCI université paris diderot Sorbonne Paris Cité Institut de Mathématiques de Jussieu-Paris Rive GaucheUMR CNRS 7586 CNRS Sorbonne Universités UPMC Univ CMLS Ecole polytechnique et CNRS Université Paris-Saclay Dipartimento di Matematica e Informatica Università degli Studi di Palermo

A formal asymptotics leading from a system of Boltzmann equations for mixtures towards either Vlasov-Navier-Stokes or Vlasov-Stokes equations of incompressible fluids was established by the same authors and Etienne Bernard in: A Derivation of the Vlasov-Navier-Stokes Model for Aerosol Flows from Kinetic Theory Commun. Math. Sci., 15: 1703–1741(2017) and A Derivation of the Vlasov-Stokes System for Aerosol Flows from the Kinetic Theory of Binary Gas Mixtures. KRM, 11: 43–69(2018). With the same starting point but with a different scaling, we establish here a formal asymptotics leading to the Vlasov-Euler system of compressible fluids. Explicit formulas for the coupling terms are obtained in two typical situations: for elastic hard spheres on one hand, and for collisions corresponding to the inelastic interaction with a macroscopic dust speck on the other hand.

关键词： Vlasov-Euler system Boltzmann equation Hydrodynamic limit Aerosols Sprays Gas mixture

Laboratory radiative accretion shocks on GEKKO XⅡlaser facility for POLAR project

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High Power Laser Science and Engineering 2018年第2期6卷 181-188页

作者： L.Van Box Som E.Falize M.Koenig Y.Sakawa B.Albertazzi E Barroso J.-***-Bidaud C.Busschaert A.Ciardi Y.Hara N.Katsuki R.Kumar E Lefevre C.Michaut Th.Michel T.Miura T.Morita M.Mouchet G.Rigon T.Sano S.Shiiba H.Shimogawara S.Tomiya CEA-DAM-DIF F-91297 ArpajonFrance LERMA Sorbonne UniversiteObservatoire de ParisUniversite PSLCNRSF-75005 ParisFrance CEA Saclay DSM/Irfu/Service d'AstrophysiqueF-91191 Gif-sur-YvetteFrance LULI-CNRS Ecole PolytechniqueCEA:Universite Paris-Saclay UPMC univ paris 06:Sorbonne universite-F-91128 Palaiseau Cedex France Graduate School of Engineering Osaka UniversitySuitaOsaka 565-0871Japan Institute of Laser Engineering Osaka UniversitySuitaOsaka 565-0871Japan Faculty of Engineering Sciences Kyushu University6-1 Kasuga-KoenKasugaFukuoka 816-8580Japan Aoyama Gakuin university Japan GEPI Observatoire de ParisPSL Research UniversityCNRSUniversite Paris DiderotSorbonne Paris CiteF-75014 ParisFrance LUTH Observatoire de ParisPSL Research UniversityCNRSUniversite Paris DiderotSorbonne Paris CiteF-92195 MeudonFrance

A new target design is presented to model high-energy radiative accretion shocks in polars. In this paper, we present the experimental results obtained on the GEKKO XII laser facility for the POLAR project. The experimental results are compared with 2 D FCI2 simulations to characterize the dynamics and the structure of plasma flow before and after the collision. The good agreement between simulations and experimental data confirms the formation of a reverse shock where cooling losses start modifying the post-shock region. With the multi-material structure of the target,a hydrodynamic collimation is exhibited and a radiative structure coupled with the reverse shock is highlighted in both experimental data and simulations. The flexibility of the laser energy produced on GEKKO XII allowed us to produce high-velocity flows and study new and interesting radiation hydrodynamic regimes between those obtained on the LULI2000 and Orion laser facilities.

关键词： accretion processes high power laser hydrodynamics laboratory astrophysics

Analytical modelling of the expansion of a solid obstacle interacting with a radiative shock

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High Power Laser Science and Engineering 2018年第2期6卷 123-132页

作者： Th.Michel E.Falize B.Albertazzi G.Rigon Y.Sakawa T.Sano H.Shimogawara R.Kumar T.Morita C.Michaut A.Casner R Barroso P.Mabey Y.Kuramitsu S.Laffite L.Van Box Som G.Gregori R.Kodama N.Ozaki P.Tzeferacos D.Lamb M.Koenig luli-cnrs ecole polytechniquecea:universite paris-saclayupmc univ paris 06:sorbonne universites-f-91128 palaiseau cedexFrance cea damdifF-91297 ArpajonFrance cea saclay dsm/irfu/service d'astrophysiqueF-91191 Gif-sur-YvetteFrance institute of laser engineering osaka universitySuitaOsaka 565-0871Japan faculty of engineering sciences kyushu university6-1 Kasuga-KoenKasugaFukuoka 816-8580Japan luth observatoire de parispsl research universitycnrsuniversite paris diderotSorbonne Paris Cite92190 MeudonFrance universite de bordeaux-cnrs-cea celia UMR 5107F-33405 TalenceFrance gepi observatoire de parispsl research universitycnrsuniversite paris diderotSorbonne Paris Cite75014 ParisFrance graduate school of engineering osaka universitySuitaOsaka 565-0871Japan lerma observatoire de parispsl research universitycnrssorbonne universitesUPMC Univ.Paris 06F-75005 ParisFrance clarendon laboratory university of oxfordParks RoadOxford OX1 3PUUK flash center for computational science university of chicagoIL 60637USA

In this paper, we present a model characterizing the interaction of a radiative shock(RS) with a solid material, as described in a recent paper(Koenig et al., Phys. Plasmas, 24, 082707(2017)), the new model is then related to recent experiments performed on the GEKKO XII laser facility. The RS generated in a xenon gas cell propagates towards a solid obstacle that is ablated by radiation coming from the shock front and the radiative precursor, mimicking processes occurring in astrophysical phenomena. The model presented here calculates the dynamics of the obstacle expansion,which depends on several parameters, notably the geometry and the temperature of the shock. All parameters required for the model have been obtained from experiments. Good agreement between experimental data and the model is found when spherical geometry is taken into account. As a consequence, this model is a useful and easy tool to infer parameters from experimental data(such as the shock temperature), and also to design future experiments.

关键词： high energy density physics laser–plasmas interaction modelling plasmas astrophysics plasma physics radiative hydrodynamics radiative shock

IGS polar motion measurement accuracy

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Geodesy and Geodynamics 2017年第6期8卷 413-420页

作者： Jim Ray Paul Rebischung Jake Griffiths National Geodetic Survey Silver Spring MD USA IGN LAREG University Paris Diderot Sorbonne Paris Cite France Naval Research Laboratory Washington DC USA

We elaborate an error budget for the long-term accuracy of IGS（International Global Navigation Satellite System Service） polar motion estimates, concluding that it is probably about 25-30 μas（1-sigma）overall, although it is not possible to quantify possible contributions（mainly annual） that might transfer directly from aliases of subdaily rotational tide errors. The leading sources are biases arising from the need to align daily, observed terrestrial frames, within which the pole coordinates are expressed and which are continuously deforming, to the secular, linear international reference frame. Such biases are largest over spans longer than about a year. Thanks to the very large number of IGS tracking stations, the formal covariance errors are much smaller,around 5 to 10 μas. Large networks also permit the systematic frame-related errors to be more effectively minimized but not eliminated. A number of periodic errors probably also influence polar motion results, mainly at annual, GPS（Global Positioning System） draconitic, and fortnightly periods, but their impact on the overall error budget is unlikely to be significant except possibly for annual tidal aliases. Nevertheless, caution should be exercised in interpreting geophysical excitations near any of the suspect periods.

关键词： PM(Polar motion) GPS(Global Positioning System) EOPs(Earth orientation parameters) Accuracy IGS(International GNSS Service)

Modeling the antigen recognition by B-cell and T-cell receptors through thermostatted kinetic theory methods

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International Journal of Biomathematics 2017年第5期10卷 263-299页

作者： Carlo Bianca Louis Brezin Laboratoire de Recherche en Eco-innovation Industrielle el Energetique ECAM-EPMI 13 Boulevard de l'Hautil 95092 Cergy Pontoise Cedex France Laboratoire de Physique Statistique Ecole Normale Supdrieure PSL Research University Universite Paris Diderot Sorbonne Paris-Cite Sorbonne Universites UPMC Univ Paris 06 CNRS 24 rue Lhomond 75005 Paris France Institut universitaire de Cancdrologie Facultg de Medecine Universite Pierre et Marie Curie-Paris 6 91 Bd de l'Hopital 75013 Paris France

The activation and the resulting response of the immune system to antigens comprise different complex processes and cells. This paper aims at modeling the processes of recognition and learning of the immune system by means of the thermostatted kinetic theory methods. Specifically, the thermostatted kinetic framework is firstly generalized for taking into account that in some processes of proliferation of the cells, the rate is also function of the degree of information exchanged amongst cells. In particular, within the new framework, a mathematical model is proposed for miming the recognition process of the immune system through the definition of interactions between the cytoto^ic and humoral components of the adaptive immune system via T- and B-cells. The model validation is obtained by performing a sensitivity analysis on the parameters which depicts the main emerging phenomena and the different phases of the recognition and learning of the immune system.

关键词： Thermostatted kinetic theory integro-differential models learning and memory biological complexity immune system.