Increasing 3D Matrix Rigidity Strengthens Proliferation and Spheroid Development of Human Liver Cells in a Constant Growth Factor Environment

International audienceMechanical forces influence the growth and shape of virtually all tissues and organs. Recent studies show that increased cell contractibility, growth and differentiation might be normalized by modulating cell tensions. Particularly, the role of these tensions applied by the extracellular matrix during liver fibrosis could influence the hepatocarcinogenesis process. The objective of this study is to determine if 3D stiffness could influence growth and phenotype of normal and transformed hepatocytes and to integrate extracellular matrix (ECM) stiffness to tensional homeostasis. We have developed an appropriate 3D culture model: hepatic cells within three-dimensional collagen matrices with varying rigidity. Our results demonstrate that the rigidity influenced the cell phenotype and induced spheroid clusters development whereas in soft matrices, Huh7 transformed cells were less proliferative, well-spread and flattened. We confirmed that ERK1 played a predominant role over ERK2 in cisplatin-induced death, whereas ERK2 mainly controlled proliferation. As compared to 2D culture, 3D cultures are associated with epithelial markers expression. Interestingly, proliferation of normal hepatocytes was also induced in rigid gels. Furthermore, biotransformation activities are increased in 3D gels, where CYP1A2 enzyme can be highly induced/activated in primary culture of human hepatocytes embedded in the matrix. In conclusion, we demonstrated that increasing 3D rigidity could promote proliferation and spheroid developments of liver cells demonstrating that 3D collagen gels are an attractive tool for studying rigidity-dependent homeostasis of the liver cells embedded in the matrix and should be privileged for both chronic toxicological and pharmacological drug screening

3D model as a dynamic compilation of knowledge: interim results on the city of Alet

[EN] The late Iron Age capital of the Coriosolites, City of Alet, scattered today in a neighbourhood of Saint-Malo( France), has become since 2015 the subject of experimentations in digital archaeology. These have led us to define as objective a relevant three-dimensional (3D)reconstruction integrating different buildings, but also a precise topography, aspart of the coastal geomorphology, environmental vegetation and naval activities. First pillar of this reconstruction, 3D laser and magnetic surveys were conducted in order to get some digitised work supports, but also to raise some scientific issues. As part of the main Roman cities of Brittany, the historical study of the City began at least at the end of the 19thcentury and archaeological excavations began in the 1970s. So knowledge present in a wide spectrum of archaeological and historical references was then compiled. 3D reconstruction of the City, editable to adapt to new contributions and scientific discoveries, allows a dynamic synthesis of archaeological knowledge accumulated along the years. Because it was done within an archaeology laboratory, it was directly monitored and controlled iteratively by researchers in the field (site, area and period). This work currently allows archaeologists to face limits and constraints regarding this scientific process and better understand the organizational aspects of the City.The CCC’ project is co-funded by the Creative Europe Programme of the European Union. It is led by the MAT (Maritime Archaeology Trust, Southampton, UK) and involves the Prehistory Department of the Universtiy of Cantabria (Santander, Spain), and the CReAAH (Centre de Recherche en Archéologie, Archéosciences, Histoire, Rennes, France). We also want to thank the company ABEM France for the loan of the Stream EM multichannel GPR used in Alet.Bernard, Y.; Barreau, J.; Bizien-Jaglin, C.; Quesnel, L.; Langouët, L.; Daire, M. (2017). 3D model as a dynamic compilation of knowledge: interim results on the city of Alet. Virtual Archaeology Review. 8(16):51-60. doi:10.4995/var.2017.5862.SWORD516081

A escola francesa se democratiza, mas a inserção social torna-se cada vez mais difícil

This study analyzes the advances and limits of measures to  make education in France more democratic, above all in the  second half of the twentieth century. It analyzes the implications of new technologies, of the establishmenteffect of education and of the sectoral-effect in decreasing school inequalities. Establishing a relationship between the increase in educational opportunities and employment rates, the study indicates that despite substantial changes in educational systems and the consequent increase in the levels of education of the French population, social inequalities persist, showing that the school still exercises an important role in social reproduction.El presente estudio analiza los avances y los límites de las medidas de democratización de la educación aplicados en Francia, en especial en la mitad del siglo XX, mediante los estudios de las implicaciones de las nuevas tecnologías, del efectoestablecimiento de la enseñanza, y del efecto-sector en la disminución de las desigualdades escolares. Al establecer una relación entre las oportunidades educacionales y los índices de empleo, el estudio indica que, a pesar de la evolución no negligenciable de los sistemas de enseñanza y de la consecuente prolongación de los niveles de formación de la población francesa, se perpetúan las desigualdades sociales mostrando que la escuela todavía ejerce un papel importante  en la reproducción social.Este estudo analisa os avanços e limites das medidas de democratização da educação aplicadas na França, sobretudo na segunda metade do século XX, através do estudo das implicações das novas tecnologias, do efeito-estabelecimento de ensino e do efeito-setor na diminuição das desigualdades escolares. Estabelecendo uma relação entre o aumento das oportunidades educacionais e os índices de emprego, o estudo indica que, apesar da evolução não negligenciável dos sistemas de ensino e da conseqüente prolongação dos níveis de formação da população francesa, as desigualdades sociais se perpetuam, a mostrar que a escola ainda exerce um papel importante na reprodução social

Multi-objective constrained optimization of engine maps

International audienceNowadays, automotive manufacturers are submitted to strong constraints in engine calibration: lowest fuel consumption, emission-control legislation and driver requests for driving comfort and performances. These constraints lead to an increasingly complexity of the engines and thus an increasingly number of parameters to be tuned, making the empirical engine calibration by a scan of parameter values impossible at engine test-bench. New methodologies in automated engine calibration based on statistics and optimization have emerged in order to limit the number of experimental tests to be run. The optimization problem of engine calibration consists in the determination of engine tuning parameter maps that minimize the cumulated fuel consumption and pollutant emissions, under combustion noise constraints, on a driving cycle. The usual way to get this result is to select specific operating points representing this cycle in the engine working range and to define upper bounds applied on the different engine responses (allocations) for each of them, in order to obtain a weighted sum of these local responses respecting the global targets. The underlying problem is a multi-objective optimization problem: different compromises between fuel consumption, noise and pollutant emissions on each operating point are possible. We propose an adapted optimization method based on the MO-CMA-ES method (Multi-objective Covariance Adaptation Evolution Strategy) which takes into account the non trivial limits of the engine parameter variation domains and some robustness constraints. An other point addressed in this paper is the map optimization which consists in a global optimization of engine responses cumulated on the driving cycle. This method avoids the cumbersome choice of allocations for each considered operating point and includes directly the map regularity constraints in map parameterizations. Finally, application on real dataset obtained at automated test-bench for a diesel engine are presented

A derivative free optimization method for reservoir characterization inverse problem

International audienceThese data (pressure, oil/water/gas rates at the wells and 4D seismic data) are compared with simulated data to determine petrophysical properties of the reservoir. The underlying optimization problem requires dedicated techniques : derivatives are often not available, the associated forward problems are CPU time consuming and some constraints may be introduced to handle a priori information. In this paper, we propose a derivative free optimization method based on trust region approach coupled with local quadratic interpolating models of the cost function and of non linear constraints. Results obtained with this method on a synthetic reservoir application with the joint inversion of production data and 4D seismic data are presented. Its performances are compared with a classical sequential quadratic programming method in terms of numbers of simulation of the forward problem

Les inégalités au Brésil et dans d'autres États émergents. Comparaisons avec un groupe témoin

Dans cet article, nous mettons en évidence le rôle excessif et nocif que les inégalités exercent quand il s’agit d’un développement qui respecte, bien que minimalement, les humains et leur environnement dans la totalité du planète. Le défi dont nous nous sommes consacrés consiste en analyser, comparativement, les pays relativement nouveaux qui intègrent le BRICS (Afrique du Sud, Brésil, Chine, Inde et Russie) avec un groupe de contrôle, qui comprend l’Allemagne, le Canada, Cuba, les États-Unis et le Japon (quatre d’entre eux appartenant à des pays du G7). Pour ce faire, nous prenons comme référence un ensemble de données sur les revenus, la santé et l’éducation, recueillies par le Programme des Nations Unies pour le développement (PNUD), en particulier l’indice de développement humain (IDH) mis en état par le prix Nobel d’économie Amartya Sen. Nos conclusions ont indiqué qu’aujourd’hui, plus qu’au moment de son élaboration il y a un demi-siècle, les théories de l’héritage culturel et de la reproduction sociale de Pierre Bourdieu et Jean-Claude Passeron (1964 et 1970) sont toujours d’actualité et en resterons pendant que les inégalités ne sont pas eradiquées.Mots-clés: Développement humain; Revenu; Santé; Éducation; Héritage culturel; Reproduction sociale

Optimization for engine calibration

International audienceNowadays, automotive manufacturers are submitted to strong constraints in engine calibration such as: low fuel consumption, emission-control legislation and driver requests for driving comfort and performances. These constraints lead to an increasing complexity of the engines and thus an increasing number of parameters to be tuned, making the empirical engine calibration by a scan of parameter values impossible at engine test-bench. New methodologies in automated engine calibration based on statistics and optimization have emerged in order to limit the number of experimental tests to be run. The optimization problem of engine calibration consists in the determination of engine tuning parameters that minimize the cumulated fuel consumption and pollutant emissions on a driving cycle generally associated with legislation norms. This cycle is decomposed in a set of stationary operating points of the engine characterized by its speed and its torque (the transient behaviors of the engine are not taken into account in the stabilized calibration). Then, the optimal tuning parameters of the engine should be defined for each operating points, the functions defining these parameters on the whole engine operating domain are called the engine maps. These two-dimensional optimal engine maps are then integrated in the engine control unit in the vehicle. We illustrate the difficulties associated with this application and propose adapted optimization methodologies: LoLiMoT models for engine map parameterization in order to handle intrinsic constraints on the map regularity, multi-objective optimization method based on CMA-ES approach. Finally , application on real dataset obtained at IFP automated test-bench for a diesel engine are presented. 2. Keywords: Engine calibration, LoLiMoT, Multi-objective optimization, Evolutionary algorithm 3. Introduction Engine calibration consists in fulfilling the engine tuning maps that are used in engine controls of the vehicle, i.e. in defining the optimal tuning of parameters used by engine control strategies. Due to the highly increased number of these parameters (especially for diesel engines but spark ignition engines are following the same trend) and the reduction of the development schedule available for the calibration process, manual tuning of engine parameters is now replaced by mathematically assisted calibration process. Such a process is based on the design of experiments with associated modeling methods, in order to reduce the number of tests used to build engine response models depending on engine control parameters, and optimization techniques to determine the optimal settings within the model definition domain. In order to perform the tests in a more productive way, these mathematical techniques are generally associated with test automation, requiring well controlled measurement methods and reliable test equipments. This paper describes the optimization methods developed for this application and illustrates their effectiveness on a real case of a common rail diesel Engine. The first section introduces the classical steps of the calibration process and discusses the associated difficulties. In the second section, we propose the Multi-Objective Covariance-Adaptation Evolutionary Strategy method for solving the optimization problem associated with a given engine operating point defined by the engine speed and the engine load. In the third part, an integrated approach is proposed in order to directly optimize the engine maps on the whole driving cycle (associated with legislation norms) instead of the individual optimization of each engine operating point. 4. Engine calibration 4.1. Sketch of the engine calibration process The emission calibration workflow is classically divided into four steps: 1. a preliminary phase consisting in choosing a sample of operating points (referred to as OP in the

Engine calibration: multi-objective constrained optimization of engine maps

International audienceWe present two new approaches to address the optimization problem associated with engine calibration. In this area, the tuning parameters are traditionally determined in a local way, i.e., at each engine operating point, via a single-objective minimization problem. To overcome these restrictions, the first method we propose is able to cope with several objective functions simultaneously in the local formulation. The second method we put forward relies on a global formulation, which allows the whole driving cycle to be taken into account while remaining single-objective. At the practical level, the two methods are implemented by combining various existing techniques such as the LoLiMoT (Local Linear Model Tree) parameterization and the MO-CMA-ES (Multi-Objective Covariance Matrix Adaptation Evolution Strategy) algorithm. A better compromise appears to be achieved on real case applications. Keywords Engine calibration · Response surface · LoLiMoT · Multi-objective optimization · Evolutionary algorithm Nomenclature Abbreviations (by alphabetical order

A Derivative Free Optimization method for reservoir characterization inverse problem

International audienceReservoir characterization inverse problem aims at building reservoir models consistent with available production and seismic data for better forecasting of the production of a field. These observed data (pressures, oil/water/gas rates at the wells and 4D seismic data) are compared with simulated data to determine unknown petrophysical properties of the reservoir. The underlying optimization problem is usually formulated as the minimization of a least-squares objective function composed of two terms : the production data and the seismic data mismatch. In practice, this problem is often solved by nonlinear optimization methods, such as Sequential Quadratic Programming methods with derivatives approximated by finite differences. In applications involving 4D seismic data, the use of the classical Gauss-Newton algorithm is often infeasible because the computation of the Jacobian matrix is CPU time consuming and its storage is impossible for large datasets like seismic-related ones. Consequently, this optimization problem requires dedicated techniques: derivatives are not available, the associated forward problems are CPU time consuming and some constraints may be introduced to handle a priori information. We propose a derivative free optimization method under constraints based on trust region approach coupled with local quadratic interpolating models of the cost function and of non linear constraints. Results obtained with this method on a synthetic reservoir application with the joint inversion of production data and 4D seismic data are presented. Its performance is compared with a classical SQP method (quasi-Newton approach based on classical BFGS approximation of the Hessian of the objective function with derivatives approximated by finite differences) in terms of number of simulations of the forward problem

Dater les anciennes pêcheries par les niveaux marins approche méthodologique et perspectives géoarchéologiques : le Bas Léon, nord Finistère, Bretagne

En conséquence directe du récent développement de l’archéologie des anciennes pêcheries, dans l’Ouest de la France (Daire et Langouët, 2008, 2010 ; Langouët et Daire, 2009) une réflexion s’engage sur l’évolution chronologique de cette forme d’exploitation du littoral au regard des variations des niveaux marins. À partir de l’analyse des règles ayant conditionné l’installation de barrages, une approche théorique très novatrice est proposée puis discutée à partir d’une zone test : le Bas-Léon (Finistère). Le choix de ce secteur géographique est justifié par l’abondance relative de structures de barrages (72) géoréférencées (y compris par rapport au niveau zéro des cartes marines) et par l’existence de données topographiques et chronologiques (prélèvements et datations) qui, bien qu’anciennes et nécessitant une actualisation, fournissent un schéma des variations relatives du niveau marin depuis sept millénaires, sur ce secteur géographique.As a direct consequence of recent development in ancient fish-traps archaeology, in Western France, (Daire et Langouët, 2008, 2010; Langouët et Daire, 2009), a discussion recently emerged about the chronological evolution of this form of coastal resources exploitation, as regards its links with sea level changes. From the analysis of rules having conditioned the installation of the weirs, a very innovative theoretical approach is proposed here and then discussed from a test zone: the Bas-Léon (Finistère). This area has been selected on the basis of several criteria: the relative abundance of fish weirs structures (72), the precisions of their location (including by reference to the present sea level reference), and the existence of topographic and chronological data (samplings and dating) related to these archaeological structures. Even though it appears necessary to update some ancient observations, this data can provide a solid basis for new considerations on sea level changes, for seven thousands of years, in this geographic area