Éditeur(s) : HAL CCSD
4ème Rencontre des Jeunes Statisticiens
Aussois, France

hal-00628106
https://hal.archives-ouvertes.fr/hal-00628106

Éditeur(s) : HAL CCSD Frontiers
Résumé : International audience
The generation of handwriting is a complex neuromotor skill requiring the interaction of many cognitive processes. It aims at producing a message to be imprinted as an ink trace left on a writing medium. The generated trajectory of the pen tip is made up of strokes superimposed over time. The Kinematic Theory of rapid human movements and its family of lognormal models provide analytical representations of these strokes, often considered as the basic unit of handwriting. This paradigm has not only been experimentally confirmed in numerous predictive and physiologically significant tests but it has also been shown to be the ideal mathematical description for the impulse response of a neuromuscular system. This latter demonstration suggests that the lognormality of the velocity patterns can be interpreted as reflecting the behavior of subjects who are in perfect control of their movements. To illustrate this interpretation, we present a short overview of the main concepts behind the Kinematic Theory and briefly describe how its models can be exploited, using various software tools, to investigate these ideal lognormal behaviors. We emphasize that the parameters extracted during various tasks can be used to analyze some underlying processes associated with their realization. To investigate the operational convergence hypothesis, we report on two original studies. First, we focus on the early steps of the motor learning process as seen as a converging behavior toward the production of more precise lognormal patterns as young children practicing handwriting start to become more fluent writers. Second, we illustrate how aging affects handwriting by pointing out the increasing departure from the ideal lognormal behavior as the control of the fine motricity begins to decline. Overall, the paper highlights this developmental process of merging toward a lognormal behavior with learning, mastering this behavior to succeed in performing a given task, and then gradually deviating from it with aging.
ISSN: 1664-1078

hal-01098124
https://hal.archives-ouvertes.fr/hal-01098124
DOI : 10.3389/fpsyg.2013.0094

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
Many iterative processes can be interpreted as discrete dynamical systems and, in certain cases, they correspond to a time discretisation of differential systems. In this article the authors propose generating numerical methods in numerical linear algebra by modelling the linear system to be solved as a given state of a dynamical system; the solution can be reached asymptotically, as a (asymptotically stable) steady state, but also as a finite time (shooting methods). In that way, any (stable) numerical scheme for the integration of such a problem can be presented as a method for solving linear systems. The authors discuss aspects of this approach, which allows them to recover some known methods but also to introduce new ones. Finally, some convergence results and numerical illustrations are presented.
ISSN: 1017-1398

hal-00730194
https://hal.archives-ouvertes.fr/hal-00730194

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
ISSN: 0378-3839

hal-00385746
https://hal.archives-ouvertes.fr/hal-00385746

Éditeur(s) : HAL CCSD
Résumé : Predicting, modelling and analysing the metabolism of xenobiotics, foreign substances to an organism, using computer methods, has been a major challenge for the scientific community for many years. This thesis aims to implement multiscale computing methods for predicting and analyzing the metabolism of xenobiotics. A first focus of this study was on the construction and de novo automatic annotation of metabolic graphs combining high sensitivity and precision. These graphs thus provide the prediction of the metabolism of xenobiotics in humans, as well as the genotoxicity of the molecules and atoms that make up xenobiotics. Then, the work focused on the implementation of a dynamic mathematical model modelling enzymatic competition effects through the development of a methodology allowing the exploitation of limited biological data while limiting inherent biases.
Prédire, modéliser et analyser le métabolisme de xénobiotiques, substances étrangères à un organisme, à l’aide de méthodes informatiques est un challenge majeur mobilisant la communauté scientifique depuis de nombreuses années. Cette thèse vise à implémenter des méthodes informatiques multi-échelles pour prédire et analyser le métabolisme des xénobiotiques. Un premier axe de cette étude portait sur la construction et l’annotation automatique de novo de graphes métaboliques combinant fortes sensibilités et précisions. Ces graphes fournissent ainsi la prédiction du métabolisme de xénobiotiques chez l’homme, ainsi que la génotoxicité des molécules et atomes qui le composent. Puis, le travail s’est orienté sur l’implémentation d’un modèle mathématique dynamique modélisant des effets de compétition enzymatique à travers le développement d’une méthodologie permettant l’exploitation de données biologiques restreintes tout en limitant les biais inhérents.
https://hal-univ-rennes1.archives-ouvertes.fr/tel-01659375

tel-01659375
https://hal-univ-rennes1.archives-ouvertes.fr/tel-01659375
https://hal-univ-rennes1.archives-ouvertes.fr/tel-01659375/document
https://hal-univ-rennes1.archives-ouvertes.fr/tel-01659375/file/these.pdf

Éditeur(s) : HAL CCSD
Résumé : International audience
Objectives: Using in silico simulations from histopathological cancer prostate specimen, the objectives were to identify the total dose corresponding to various fractionations necessary to destroy the tumor cells (50% to 99.9%) and to assess the impact of the Gleason score on those doses. © 2017 IEEE.
14th IEEE International Symposium on Biomedical Imaging, ISBI 2017
Melbourne, Australia

hal-01618934
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01618934
DOI : 10.1109/ISBI.2017.7950643

Éditeur(s) : HAL CCSD Springer International Publishing
Résumé : Industrial agriculture has clearly reached its limits. Industrial agriculture is not able anymore to satisfy the basic needs of the growing worldwide population while ensuring the conditions of reproduction of natural assets. New production models have to be designed to protect and reclame polluted and degraded agricultural areas. Agroecology is considered as a promising way to achieve ecologically-intensive agrosystems, since the seminal contribution of Altieri in 1995. Nevertheless agroecology has not fully emerged as a scientific discipline yet. Agroecology is more that a traditional scientific discipline because agroecology breaks the frontiers between biophysical sciences and social sciences. This chapter reviews the roots and evolution of agroecology in the first section. Here we propose a mathematical theory of viability to handle uncertainty and complexity within agrosystems. This theory allows to define a kern of viability in which the agrosystem stay viable in the long term (section “Scientific stakes: New frontiers”). However, agroecological innovations create new uncertainties and controversies that must be solved. Some solutions can be found individually while other solutions must by co-constructed using innovative collective actions and hydrid forums (Callon et al. 2001, section “Scientific controversy and uncertainty”). Such collective knowledge makes agroecology as the starting point of a representative democracy by setting up adaptive governance on territories (section “How to manage agrosystems in the context of global changes?”).
Sustainable Agriculture Reviews 14

ISBN : 978-3-319-06015-6
hal-01195372
https://hal.archives-ouvertes.fr/hal-01195372
DOI : 10.1007/978-3-319-06016-3_1
PRODINRA : 270790

Éditeur(s) : HAL CCSD Geological Society of London
Résumé : This paper presents the background for the calculation of physical properties of an aggregate from constituent crystal properties and the texture of the aggregate in a coherent manner. Emphasis is placed on the important tensor properties of 2nd and 4th rank with applications in rock deformation, structural geology, geodynamics and geophysics. We cover texture information that comes from pole figure diffraction and single orientation measurements (electron backscattered diffraction or EBSD, electron channelling pattern, Laue pattern, optical microscope universal-stage). In particular, we provide explicit formulae for the calculation of the averaged tensor from individual orientations or from an orientation distribution function (ODF). For the latter we consider numerical integration and an approach based on the expansion into spherical harmonics. This paper also serves as a reference paper for the mathematical tensor capabilities of the texture analysis software MTEX, which is a comprehensive, freely available MatLab toolbox that covers a wide range of problems in quantitative texture analysis, for example, ODF modelling, pole figure to ODF inversion, EBSD data analysis and grain detection. MTEX offers a programming interface which allows the processing of involved research problems as well as highly customizable visualization capabilities; MTEX is therefore ideal for presentations, publications and teaching demonstrations.
Deformation Mechanisms, Rheology and Tectonics: Microstructures, Mechanics and Anisotropy

hal-00688833
https://hal.archives-ouvertes.fr/hal-00688833

Éditeur(s) : HAL CCSD Institute for Scientific Computing and Information
Résumé : International audience
The production of oil in soft highly compacted reservoirs produces a significant reduction in the pore space which in turn causes the surface to subside. The authors couple two simulators to model the mechanical deformations in the presence of a Darcy flow, both one- and two-phase. The simulators solve for flow in a porous medium using a finite volume method, and solve for the mechanical deformation of the porous media using a finite element method. The flow equations and the deformation equations are coupled using Biot's law. The authors use two different methods for the coupling: the first uses a staggered algorithm; the second is based on a preconditioned conjugate method. The authors use a multiscale method in both approaches. The authors show that the inf-sup condition is not satisfied, because of the mixed discretization which is done by using two separate simulators. The authors give convergence comparisons for the two methods for several examples. Two of the examples are for the linear problem (one-phase) where they know the exact solution and one is for the nonlinear problem (two-phase). In all cases, the preconditioned conjugate algorithm is faster and more robust, in particular when the inf-sup condition is not satisfied. In the nonlinear problem the authors state that the results agree with physical predictions but do not give actual empirical data. Finally, they show the effects of grid orientation on the nonlinear problem.
ISSN: 1705-5105

hal-00730673
https://hal.archives-ouvertes.fr/hal-00730673

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Evidence of the impact of exposure to lowlevels of lead on children's health is increasing. Residential floor dust is the assumed origin of lead exposure by young children. In this study, we estimate the contribution of different lead sources to household interior floor dust contamination. We also estimate the within-home variability of interior floor dust lead loadings. A multilevel model was developed based on data collected in a French survey in 2008-2009 (484 housing units, 1834 rooms). Missing data were handled by multiple imputation using chained equations. The intra-home correlation between interior floor Log dust lead loadings was approximately 0.6. Dust lead from the landing of an apartment, mostly originating outside the building, was the major contributor to interior floor dust lead. Secondary contributors included the lead-based paint on exterior railings, track-in of the exterior soil of the children's play area into the dwelling, smoking inside the home, demolition of nearby old buildings and sites of pollution in the vicinity. Interior lead-based paint contaminated interior floor dust only in old and non-renovated dwellings. To reduce interior floor dust lead levels in the general population of dwellings, common areas should be maintained, and track-in from the outside should be limited as much as possible.
Science of the Total Environment

hal-00997780
https://hal.archives-ouvertes.fr/hal-00997780
DOI : 10.1016/j.scitotenv.2013.10.028

Éditeur(s) : HAL CCSD INRIA
Résumé : International audience
Markov chain Monte Carlo (MCMC) methods together with hidden Markov models are extensively used in the Bayesian inference for many scientific fields like environment and ecology. Through simulated examples we show that the speed of convergence of these methods can be very low. In order to improve the convergence properties, we propose a method to make parallel chains interact. We apply this method to a biomass evolution model for fisheries.
Les méthodes de Monte Carlo par chaînes de Markov (MCMC) couplées à des modèles de Markov cachés sont utilisées dans de nombreux domaines, notamment en environnement et en écologie. Sur des exemples simples, nous montrons que la vitesse de convergence de ces méthodes peut être très faible. Nous proposons de mettre en interaction plusieurs algorithmes MCMC pour accélérer cette convergence. Nous appliquons ces méthodes à un modèle d'évolution de la biomasse d'une pêcherie.
ISSN: 1638-5713

inria-00506386
https://hal.inria.fr/inria-00506386
https://hal.inria.fr/inria-00506386/document
https://hal.inria.fr/inria-00506386/file/campillo2008d.pdf

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
Chaperone synthesis in response to proteotoxic stress is dependent on a family of transcription factors named heat shock factors (HSFs). The two main factors in this family, HSF1 and HSF2, are co-expressed in numerous tissues where they can interact and form heterotrimers in response to proteasome inhibition. HSF1 and HSF2 exhibit two alternative splicing isoforms, called α and β, which contribute to additional complexity in HSF transcriptional regulation, but remain poorly examined in the literature. In this work, we studied the transcriptional activity of HSF1 and HSF2 splicing isoforms transfected into immortalized Mouse Embryonic Fibroblasts (iMEFs) deleted for both Hsf1 and Hsf2, under normal conditions and after proteasome inhibition. We found that HSF1α is significantly more active than the β isoform after exposure to the proteasome inhibitor MG132. Furthermore, we clearly established that, while HSF2 had no transcriptional activity by itself, short β isoform of HSF2 exerts a negative role on HSF1β-dependent transactivation. To further assess the impact of HSF2β inhibition on HSF1 activity, we developed a mathematical modelling approach which revealed that the balance between each HSF isoform in the cell regulated the strength of the transcriptional response. Moreover, we found that cellular stress such as proteasome inhibition could regulate the splicing of Hsf2 mRNA. All together, our results suggest that relative amounts of each HSF1 and HSF2 isoforms quantitatively determine the cellular level of the proteotoxic stress response.
ISSN: 1932-6203

inserm-00814784
http://www.hal.inserm.fr/inserm-00814784
http://www.hal.inserm.fr/inserm-00814784/document
http://www.hal.inserm.fr/inserm-00814784/file/journal.pone.0056085.pdf
DOI : 10.1371/journal.pone.0056085