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Cuticle are multifunctional hydrophobic biocomposites that protect aerial organs of plants. Along plant development, plant cuticle must accommodate different mechanical constraints combining extensibility and stiffness, the corresponding structure-function relationships are unknown. Recent data showed a fine architectural tuning of the cuticle architecture and the corresponding chemical clusters along fruit development which raise the question of their impact on the mechanical properties of the cuticle.We investigated the in-depth nanomechanical properties of tomato fruit cuticle from early development to ripening, in relation to chemical and structural heterogeneities by developing a correlative multimodal imaging approach.Unprecedented sharps heterogeneities were evidenced with the highlighting of an in-depth mechanical gradient and a ‘soft’ central furrow that were maintained throughout the plant development despite the overall increase in elastic modulus. In addition, we demonstrated that these local mechanical areas are correlated to chemical and structural gradients.This study shed light on a fine tuning of mechanical properties of cuticle through the modulation of their architecture, providing new insight for our understanding of structure-function relationships of plant cuticle and for the design of biosinpired material. more...

The cuticle is a complex polymer matrix that protects all aerial organs of plants, fulfills multiple roles in plant–environment interactions, and is critical for plant development. These functions are associated with the structural features of cuticles, and the architectural modeling of cuticles during plant development is crucial for understanding their physical properties and biological functions. In this work, the in-depth architecture of the cutin polymer matrix during fruit development was investigated. Using cherry tomato fruit (Solanum lycopersicum) as a model from the beginning of the cell expansion phase to the red ripe stage, we designed an experimental scheme combining sample pretreatment, Raman mapping, multivariate data analyses, and biochemical analyses. These approaches revealed clear chemical areas with different contributions of cutin, polysaccharides, and phenolics within the cutin polymer matrix. Besides, we demonstrated that these areas are finely tuned during fruit development, including compositional and macromolecular rearrangements. The specific spatiotemporal accumulation of phenolic compounds (p-coumaric acid and flavonoids) suggests that they fulfill distinct functions during fruit development. In addition, we highlighted an unexpected dynamic remodeling of the cutin-embedded polysaccharides pectin, cellulose, and hemicellulose. Such structural tuning enables consistent adaption of the cutin-polysaccharide continuum and the functional performance of the fruit cuticle at the different developmental stages. This study provides insights into the plant cuticle architecture and in particular into the organization of the epidermal cell wall-cuticle. more...

A non-destructive thermographic methodology based on the temperature field is utilized to determine the crack tip position during the very high cycle fatigue (VHCF) test of pure iron and deduce the corresponding fatigue crack growth rate (FCGR). To this end, a piezoelectric fatigue machine is employed to test 1 mm thick pure iron samples at 20 kHz in push–pull fatigue loading. Two cameras are placed on each side of the plate sample, an infrared one for measuring the temperature fields on the specimen surface and an optical one for visualizing the crack tip verification. The centre section of the specimen is notched to initiate the crack. The temperature field is converted into intrinsic dissipation to quantify the inelastic strain energy according to energy conservation. The maximum value of intrinsic dissipation in each thermal image is related to the position of the crack tip and thus allows monitoring of the crack evolution during the fatigue test. The obtained results show that one specific specimen broke at 7.25 × 107 cycles in the presence of a very low-stress amplitude (122 MPa). It is observed that the intrinsic dissipation has a low-constant level during the initiation and the short cracking, then sharply grows during the long cracking. This transition is visible on the polished surface of the sample, where the plasticity appears during the long cracking and slightly before. The material parameters in the Paris equation obtained from the intrinsic dissipation in the short crack growth are close to the results available in the literature as well as those obtained by the optical camera. more...

Les publications scientifiques sur le management – articles, communications, ouvrages – sont florissantes depuis de nombreuses annees, notamment dans les champs de la sociologie et des sciences de gestion. Elles commencent a le devenir dans d’autres disciplines comme l’ergonomie par exemple. Figure emblematique des questions de travail, le management a toujours ete – et reste encore – une preoccupation majeure pour « optimiser » le fonctionnement des entreprises, la productivite, l’organisati... more...

The tomato (Solanum lycopersicum) fruit has a thick, astomatous cuticle that has become a model for the study of cuticle formation, structure, and properties in plants. Tomato is also a major horticultural crop and a long-standing model for research in genetics, fruit development, and disease resistance. As a result, a wealth of genetic resources and genomic tools have been established, including collections of natural and artificially induced genetic diversity, introgression lines of genome fragments from wild relatives, high-quality genome sequences, phenotype and gene expression databases, and efficient methods for genetic transformation and editing of target genes. This mini-review reports the considerable progresses made in recent years in our understanding of cuticle by using and generating genetic diversity for cuticle-associated traits in tomato. These include the synthesis of the main cuticle components (cutin and waxes), their role in the structure and properties of the cuticle, their interaction with other cell wall polymers as well as the regulation of cuticle formation. It also addresses the opportunities offered by the untapped germplasm diversity available in tomato and the current strategies available to exploit them. more...

Visant des rapprochements entre ergonomie, sociologie et sciences de gestion, ce mémoire d’HDR, qui s’appuie sur une pratique d’interventions en entreprise, s’intéresse aux modalités d’intervention sur l’organisation à travers le travail des managers. Leur rôle dans la capacité de régulation organisationnelle (technique et décisionnelle) des entreprises, leur participation active aux changements ou encore le regard sur le travail de leurs équipes, et le leur, seront ainsi mis en avant. more...

Polyesters, as they exist in planta, are promising materials with which to begin the development of “green” replacements. Cutin and suberin, polyesters found ubiquitously in plants, are prime candidates. Samples enriched for plant polyesters, and in which their native backbones were largely preserved, were studied to identify “natural” structural features; features that influence critical physical properties. Quantitative nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), and X-ray scattering methods were used to quantify structure–property relationships in these polymeric materials. The degree of esterification, namely, the presence of acylglycerol linkages in suberin and of secondary esters in cutin, and the existence of mid-chain epoxide groups defining the packing of the aliphatic chains were observed. This packing determines polymer crystallinity, the resulting crystal structure, and the melting temperature. To evaluate the strength of this rule, tomato cutin from the same genotype, studying wild-type plants and two well-characterized mutants, was analyzed. The results show that cutin’s material properties are influenced by the amount of unbound aliphatic hydroxyl groups and by the length of the aliphatic chain. Collectively, the acquired data can be used as a tool to guide the selection of plant polyesters with precise structural features, and hence physicochemical properties., A detailed insight into plant polyesters identifies correlations of structural features with physical properties that are translated into five essential rules for the development of novel green materials. more...

The biopolyester cutin is ubiquitous in land plants, building the polymeric matrix of the plant's outermost defensive barrier, the cuticle. Cutin influences many biological processes in planta; however, due to its complexity and highly branched nature, the native structure remains partially unresolved. Our aim was to define an original workflow for the purification and systematic characterization of the molecular structure of cutin. To purify cutin we tested the ionic liquids cholinium hexanoate and 1-butyl-3-methyl-imidazolium acetate. The ensuing polymeric materials are highly esterified, amorphous, and have a typical monomeric composition as demonstrated by solid-state NMR, complemented by spectroscopic, thermal, and x-ray scattering analyses. We performed a systematic study by solution-state NMR of cryogenically milled cutins extracted from tomatoes (Solanum lycopersicum 'Micro-Tom'; the wild type and the GLYCEROL-3-PHOSPHATE ACYLTRANSFERASE [GPAT6] and CUTIN SYNTHASE [CUS1] mutants). We resolved their molecular structures, relative distribution of ester aliphatics, free acid end-groups and free hydroxyl groups, differentiating between those derived from primary and secondary esters. Our data demonstrate the existence of free hydroxyl groups in cutin and provide insight into how the mutations affect the esterification arrangement of cutin. The usage of ionic liquids for studying plant polyesters has advantages over conventional approaches, since simple modifications can be applied to recover a biopolymer carrying distinct types/degrees of modifications (e.g. preservation of esters or cuticular polysaccharides), which in combination with the solution NMR methodologies developed here, constitutes essential tools to fingerprint the multifunctionality and the structure of cutin in planta. more...

The biopolyester cutin is ubiquitous in land plants, building the polymeric matrix of the plant’s outermost defensive barrier - the cuticle. Cutin influences many biological processesin plantahowever due to its complexity and highly branched nature, the native structure remains partially unresolved. Our aim was to define an original workflow for the purification and systematic characterisation of the molecular structure of cutin. To purify cutin we tested the ionic liquids cholinium hexanoate and 1-butyl-3-methyl-imidazolium acetate. The ensuing polymers are highly esterified, amorphous and have the typical monomeric composition as demonstrated by solid state NMR, complemented by spectroscopic (GC-MS), thermal (DSC) and x-ray scattering (WAXS) analyses. A systematic study by solution-state NMR of cryogenically milled cutins extracted from Micro-Tom tomatoes (the wild type and thegpat6andcus1mutants) was undertaken. Their molecular structures, relative distribution of ester aliphatics, free acid end-groups and free hydroxyl groups, differentiating between those derived from primary and secondary esters, were solved. The acquired data demonstrate the existence of free hydroxyl groups in cutin and reveal novel insights on how the mutations impact the esterification arrangement of cutin. Compared to conventional approaches, the usage of ionic liquids for the study of plant polyesters opens new avenues since simple modifications can be applied to recover a biopolymer carrying distinct types/degrees of modifications (e.g. preservation of esters or cuticular polysaccharides), which in combination with the solution NMR methodologies developed here, constitutes now essential tools to fingerprint the multi-functionality and the structure of cutinin planta. more...

The cuticle is an essential and ubiquitous biological polymer composite covering aerial plant organs, whose structural component is the cutin polyester entangled with cell wall polysaccharides. The nature of the cutin-embedded polysaccharides (CEPs) and their association with cutin polyester are still unresolved Using tomato fruit as a model, chemical and enzymatic pretreatments combined with biochemical and biophysical methods were developed to compare the fine structure of CEPs with that of the noncutinized polysaccharides (NCPs). In addition, we used tomato fruits from cutin-deficient transgenic lines cus1 (cutin synthase 1) to study the impact of cutin polymerization on the fine structure of CEPs. Cutin-embedded polysaccharides exhibit specific structural features including a high degree of esterification (i.e. methylation and acetylation), a low ramification of rhamnogalacturonan (RGI), and a high crystallinity of cellulose. In addition to decreasing cutin deposition and polymerization, cus1 silencing induced a specific modification of CEPs, especially on pectin content, while NCPs were not affected. This new evidence of the structural specificities of CEPs and of the cross-talk between cutin polymerization and polysaccharides provides new hypotheses concerning the formation of these complex lipopolysaccharide edifices. more...

A partir de uma intervenção ergonómica relativa ao acompanhamento de uma mudança organizacional numa Seguradora de saúde, interessamo-nos, neste artigo, nas aprendizagens dos futuros “utilizadores da organização”. Desenvolvemos um ponto de vista segundo o qual a intervenção ergonómica se pode construir de tal modo que permita aos operadores adquirir conhecimento sobre o funcionamento futuro da organização. Para isto, parece-nos indispensável implicar os futuros utilizadores na concepção da organização futura. Neste sentido, propomos articular a intervenção ergonómica em torno de uma “experimentação”, dando espaço a testes sobre a organização, permitindo assim aos operadores participar nas escolhas e experimentá-las. A partir de una intervención ergonómica de acompañamiento de un cambio organizativo en una Mútua de salud, nos interesamos, en este papel, por los aprendizajes de los futuros “usuarios de la organización”. Desarrollamos la idea según la cual la intervención ergonómica puede construirse de tal forma que permita a los operadores adquirir conocimientos sobre el funcionamiento futuro de la organización. Para eso, nos parece imprescindible involucrar a los futuros usuarios en la concepción de la futura organización. En este sentido, proponemos desarrollar la intervención ergonómica en torno a una “experimentación”, que incluye varias pruebas de la organización prevista, permitiendo así a los operadores participar en las elecciones y probarlos. À partir d’une intervention ergonomique concernant l’accompagnement d’un changement organisationnel dans une Mutuelle de santé, nous nous intéressons, dans ce papier, aux apprentissages des futurs “ utilisateurs de l’organisation ». Nous développons un point de vue selon lequel l’intervention ergonomique peut se construire de telle façon qu’elle permet aux opérateurs d’acquérir des connaissances sur le fonctionnement futur de l’organisation. Pour cela, il nous paraît indispensable d’impliquer les futurs utilisateurs à la conception de la future organisation. Dans ce sens, nous proposons d’articuler l’intervention ergonomique autour d’une “ expérimentation », laissant place à des tests sur l’organisation, permettant ainsi aux opérateurs de participer aux choix et de les éprouver. Starting from an ergonomic intervention for organizational redesign in a mutual health insurance company, in this paper our interest is in the learning of future “users of the organization”. We develop a point of view according to which the ergonomic intervention can be designed to help future users learn about the future functioning of the organization. With this in mind, it is essential to involve future users in the organizational design. Following this direction, we propose to set the ergonomic intervention around îexperimentation”, with repeated tests on the planned organization, thus allowing the operators to participate in the choices and to test them. more...

Cet article présente les principales conclusions d’une thèse en ergonomie portant sur le travail des représentants du personnel dans plusieurs CHSCT de la SNCF. Ces éléments sont de nature à éclairer certains déterminants d’une activité qu’il s’agit de favoriser, pour qu’elle puisse justement contribuer à l’amélioration des conditions de travail. Après une présentation du cadre et de la méthodologie d’une recherche-intervention, nous en présenterons les principaux enseignements. L’activité des représentants du personnel est ici considérée comme relevant de la résolution collective de problème de conception. Nous montrerons les difficultés qu’ils ont à intégrer les salariés et à mobiliser le travail lors de cette résolution des problématiques qui parcourent l’entreprise. Nous pourrons alors décrire les principaux enjeux méthodologiques pour des interventions ergonomiques qui se proposent justement de développer la capacité des représentants du personnel à traiter les questions du travail. Il s’agit de les outiller pour qu’ils puissent penser, agir et débattre autrement à la fois du travail des salariés, mais également de leur propre travail au sein du CHSCT. This article presents the main conclusions of an ergonomic thesis on the activity of staff representatives in CHSCTs (occupational health and safety committees) at the SNCF. These elements may shed new light on certain determinants of an activity that can be developed to help improve working conditions. After a presentation of the framework and methodology of an intervention-research study, we will present the main lessons learned. The activity of the staff representatives is here considered as a collective resolution of design problems. We will show the difficulties they have in integrating employees and mobilizing work during the resolution of issues that exist throughout the company. We will then be able to describe the main methodological guidelines for ergonomic interventions that aim to develop the capacity of staff representatives to deal with work related issues. It is about providing them with tools so that they can think, act and debate differently about both the work of the employees and their own work. more...

This work compares the thermal responses of an α-iron and two carbon steels (C12 and C65 steel) via in-situ infrared thermography under 20 kHz ultrasonic tension-compression fatigue testing. The α-iron has only ferrite phase, and C12 and C65 steels have ferrite-pearlite dual phases. During a series of interrupted self-heating tests, the surface temperature of the three materials increases gradually with stress amplitude, while the relation is non-linear. The increase of carbon content, inducing the pearlite phase percentage increasing, results in a lower temperature increase and higher fatigue strength. For the three materials, at a certain stress amplitude level, the specimen temperature suddenly increases to hundreds of degrees. Moreover, the dissipated energy per cycle is estimated based on the 1D heat diffusion equation and a power function between dissipated energy per cycle and stress amplitude is found. Finally, the mechanisms driving the observed thermal responses are discussed. more...

Voltage sags have a high impact on the proper equipment operation and the electric power end-user processes continuity. Economic losses are a growing problem for the electric utilities, regulators and electric energy final customers and therefore, the formulation of new mathematical methods for voltage sags diagnosis are needed. In this sense, the state estimation methods seek the determination of the frequency or the number of voltage sags that an end-user would experience. In this research area, optimization problems based on techniques such as singular value decomposition, voltage profile curve fitting and voltage sag source location have been formulated. The results of these approaches may be inaccurate when the pre-fault currents, non-zero fault impedances and unbalanced conditions are considered. We will evidence that the results from singular value decomposition method are inaccurate considering these real fault conditions. Also, a new mathematical formulation of the voltage sag state estimation problem based on ℓ1-norm minimization is proposed in this work. The proposed method is applied and validated to the IEEE 33-node test distribution network. Voltage sags caused for network faults are only considered. The results validate a remarkable improvement in comparison with the singular value decomposition method and show an innovative tool for voltage sags state estimation in radial electric power distribution systems more...

International audience; Cuticle function is closely related to the structure of the cutin polymer. However, the structure and formation of this hydrophobic polyester of glycerol and hydroxy/epoxy fatty acids has not been fully resolved. An apoplastic GDSL-lipase known as CUTIN SYNTHASE1 (CUS1) is required for cutin deposition in tomato (Solanum lycopersicum) fruit exocarp. In vitro, CUS1 catalyzes the self-transesterification of 2-monoacylglycerol of 9(10),16-dihydroxyhexadecanoic acid, the major tomato cutin monomer. This reaction releases glycerol and leads to the formation of oligomers with the secondary hydroxyl group remaining nonesterified. To check this mechanism in planta, a benzyl etherification of nonesterified hydroxyl groups of glycerol and hydroxy fatty acids was performed within cutin. Remarkably, in addition to a significant decrease in cutin deposition, mid-chain hydroxyl esterification of the dihydroxyhexadecanoic acid was affected in tomato RNA interference and ethyl methanesulfonate-cus1 mutants. Furthermore, in these mutants, the esterification of both sn-1,3 and sn-2 positions of glycerol was impacted, and their cutin contained a higher molar glycerol-to-dihydroxyhexadecanoic acid ratio. Therefore, in planta, CUS1 can catalyze the esterification of both primary and secondary alcohol groups of cutin monomers, and another enzymatic or nonenzymatic mechanism of polymerization may coexist with CUS1-catalyzed polymerization. This mechanism is poorly efficient with secondary alcohol groups and produces polyesters with lower molecular size. Confocal Raman imaging of benzyl etherified cutins showed that the polymerization is heterogenous at the fruit surface. Finally, by comparing tomato mutants either affected or not in cutin polymerization, we concluded that the level of cutin cross-linking had no significant impact on water permeance. more...

Changing the balance between ascorbate, monodehydroascorbate, and dehydroascorbate in plant cells by manipulating the activity of enzymes involved in ascorbate synthesis or recycling of oxidized and reduced forms leads to multiple phenotypes. A systems biology approach including network analysis of the transcriptome, proteome and metabolites of RNAi lines for ascorbate oxidase, monodehydroascorbate reductase and galactonolactone dehydrogenase has been carried out in orange fruit pericarp of tomato (Solanum lycopersicum). The transcriptome of the RNAi ascorbate oxidase lines is inversed compared to the monodehydroascorbate reductase and galactonolactone dehydrogenase lines. Differentially expressed genes are involved in ribosome biogenesis and translation. This transcriptome inversion is also seen in response to different stresses in Arabidopsis. The transcriptome response is not well correlated with the proteome which, with the metabolites, are correlated to the activity of the ascorbate redox enzymes—ascorbate oxidase and monodehydroascorbate reductase. Differentially accumulated proteins include metacaspase, protein disulphide isomerase, chaperone DnaK and carbonic anhydrase and the metabolites chlorogenic acid, dehydroascorbate and alanine. The hub genes identified from the network analysis are involved in signaling, the heat-shock response and ribosome biogenesis. The results from this study therefore reveal one or several putative signals from the ascorbate pool which modify the transcriptional response and elements downstream. more...

Le Comité d’hygiène, de sécurité et des conditions de travail (CHSCT) s’avère, en France, une pièce maitresse des dispositifs de prévention des risques et d’amélioration des conditions de travail dans les entreprises. Bien que son rôle soit de plus en plus reconnu, il a souvent des difficultés à fonctionner et à trouver sa place dans le paysage des relations professionnelles.Cette situation est liée, d’une part, à la nature même du comité — à la fois institution de représentation du personnel et instance chargée de la prévention des risques de manière coordonnée avec les services de l’entreprise — et, d’autre part, aux caractéristiques de son champ d’intervention. La conduite des actions et leur efficience sont directement en lien avec la capacité du CHSCT à mettre en discussion des conceptions différentes, et parfois opposées, en matière de conditions de travail, de santé, de risques professionnels et d’exercice du mandat représentatif. Les représentations qu’ont les différents acteurs de ces questions contribuent à la définition des choix stratégiques et des actions à entreprendre.Notre travail de recherche s’est appuyé sur deux types de données. D’abord celles recueillies, au moyen d’entretiens et d’observations participantes, auprès de 27 CHSCT dans des entreprises de tailles et de secteurs d’activité très variés. Ensuite, des données collectées au moyen d’une grille de questionnement auprès de plus de 100 CHSCT lors de sessions de formation ou d’interventions dans des entreprises sur une période de cinq ans, et de la consultation de procès-verbaux de réunion ou de documents d’information remis aux membres de l’instance.L’objectif de cet article est de montrer que si les tensions qui traversent l’activité du CHSCT sont, en grande partie, inhérentes aux caractéristiques de cette instance et si elles sont fréquemment à l’origine de conflits, elles sont aussi une source de débats féconds qui constituent un espace de créativité pour le développement de l’action collective. Au-delà des CHSCT en France, nous sommes convaincus que les conclusions de cette recherche concernent toute instance chargée de la prévention et de l’amélioration des conditions de travail dans les entreprises à travers le monde., The Committee for Hygiene, Safety and Working Conditions (CHSW) is a key part of the system of occupational risk prevention and improvement of working conditions in French companies. While its role is increasingly recognized, it often has difficulties functioning and finding its place in the industrial relations landscape.This situation is linked, on the one hand, to the nature of the Committee—which is at the same time an employee representation body and a risk prevention body working in coordination with the company’s other departments—and, on the other, to the scope of its intervention. Its actions and their efficiency are directly related to the CHSW’s ability to discuss different and sometimes opposing conceptions of working conditions, health, occupational risks, and the exercise of the representation mandate. The different conceptions of the various actors involved will influence the strategy and actions of the Committee.Our research relies on two kinds of data. Those collected through interviews and participant observations of 27 CHSW in companies of various sizes and industrial sectors. Other data were collected by means of a questionnaire in more than 100 CHSW during training sessions and interventions in companies over a period of five years and through the consultation of minutes of meetings or briefing materials issued to members attending such meetings.The aim of this paper is to show that, while the tensions running through the activity of the CHSW are, for a large part, inherently related to its characteristics, and are frequently the cause of conflicts, they are also a source of fruitful debate and constitute an area of creativity for the development of collective action. In addition to the CHSW in France, we are convinced that the conclusions of this research can be applied to any body responsible for risk prevention and the improvement of working conditions in companies across the world., El Comité de Higiene, seguridad y Condiciones de Trabajo (CHSCT) es considerado en Francia, como una piedra angular de los dispositivos de prevención de los riesgos y de mejora de las condiciones de trabajo en las empresas. Aunque su rol es cada vez más reconocido, el Comité enfrenta a menudo ciertas dificultades para funcionar y encontrar su lugar en el paisaje de las relaciones laborales.Esta situación está vinculada, de un lado, a la naturaleza misma del comité — a la vez institución de representación del personal e instancia encargada de prevenir los riesgos de manera coordinada con los servicios de la empresa — y, de otro lado, a las características de su campo de intervención. La conducción de las acciones y su eficiencia están directamente vinculadas a la capacidad del CHSCT para discutir concepciones diferentes, y a veces opuestas, en lo que conciernen las condiciones de trabajo, la salud, los riesgos ocupacionales y el ejercicio del mandato representativo. Las representaciones que tienen los diferentes actores de dichas cuestiones contribuyen a la definición de opciones estratégicos y de las acciones a adoptar.Nuestro trabajo de investigación se apoyó sobre dos tipos de datos. En primer lugar, aquellos recogidos por medio de entrevistas y de observaciones participantes con 27 CHSCT de empresas de talla y sectores de actividad muy variados. Luego, los datos recopilados mediante una guía de cuestionamiento con más de 100 CHSCT utilizada durante las sesiones de formación o de intervenciones en las empresas, durante un periodo de cinco años, y así mismo, con la consulta de procesos verbales des reuniones o de documentos de información remitidos a los miembros de la instancia.El objetivo de este artículo es de mostrar que, si es verdad que las tensiones que atraviesan la actividad del CHSCT son, en gran parte, inherentes a las características de esta instancia y si estas se encuentran a menudo al origen de los conflictos, ellas son también una fuente de debates fecundos que constituyen un espacio de creatividad para el desarrollo de la acción colectiva. Más allá de las CHSCT en Francia, estamos convencidos que las conclusiones de esta investigación conciernen toda instancia encargada de la prevención y de la mejora de las condiciones de trabajo en las empresas a través el mundo. more...

International audience

Improving crop productivity and quality while promoting sustainable agriculture have become major goals in plant breeding. The cuticle is a natural film covering the aerial organs of plants and consists of lipid polyesters covered and embedded with wax. The cuticle protects plants against water loss and pathogens and affects traits with strong impacts on crop quality such as, for horticultural crops, fruit brightness, cracking, russeting, netting, and shelf life. Here we provide an overview of the most important cuticle-associated traits that can be targeted for crop improvement. To date, most studies on cuticle-associated traits aimed at crop breeding have been done on fleshy fruits. Less information is available for staple crops such as rice, wheat or maize. Here we present new insights into cuticle formation and properties resulting from the study of genetic resources available for the various crop species. Our review also covers the current strategies and tools aimed at exploiting available natural and artificially induced genetic diversity and the technologies used to transfer the beneficial alleles affecting cuticle-associated traits to commercial varieties. more...

Objectif L’objectif est de rendre compte des resultats d’une recherche–intervention, financee par l’ANSES, d’une duree de 3 ans, qui s’est deroulee dans une quinzaine de SST, dont certains ont ete accompagnes dans le developpement du travail collectif pluridisciplinaire afin d’elaborer des ressources psychosociales et d’innover dans l’organisation du travail. Methodologie Plusieurs approches ont ete elaborees : d’une part, comprehensive, pour avoir des monographies de la pluridisciplinarite en SST, a partir d’entretiens individuels (78), d’analyse de documents et de reunions collectives (30). D’autre part, a visee d’intervention, pour permettre aux acteurs de participer au changement, avec des methodologies de l’ergonomie (observation, entretien d’auto-confrontation, espaces de debat sur le futur et simulation organisationnelle) et de la clinique du travail (entretiens du sosie, auto-confrontation croisee). De plus une comparaison du contexte legislatif et de ses effets sur le travail collectif pluridisciplinaire a ete realisee entre la France et le Canada. Resultats Dans le contexte de reformes francaises de changements du SST, la mise en œuvre de la pluridisciplinarite fait l’objet de tensions vives entre les metiers anciens (les medecins du travail) et les novices, dont le metier et la legitimite aupres des salaries/entreprises sont en construction. Le travail collectif inter-metiers ne se decrete pas et implique prealablement de construire des collectifs de travail metier afin de pouvoir debattre de l’activite collective reelle, de ses empechements et d’elaborer des regles de fonctionnement pour repondre aux demandes des salaries/entreprises et faire face aux situations critiques. Cela participe au developpement de l’activite collective, qui est le point de depart pour questionner les modes de fonctionnement de la pluridisciplinarite dans l’organisation du travail (par ex. l’accueil des adherents, les actions prioritaires de prevention, le suivi des salaries, etc.). Les espaces de debats sur le travail reel, qui reposent sur la confrontation entre les professionnels sur les contraintes et ressources de chacun dans l’exercice de son activite, apparaissent une condition de construction de l’activite collective inter-metiers pour concevoir l’organisation du travail. Il apparait tout aussi necessaire de tenir compte de l’activite des directions, de leur CA et du point de vue des adherents, des salaries pour alimenter la reflexion sur les choix possibles des principes qui guident la conception l’organisation, afin de pouvoir soutenir le developpement de l’activite des professionnels. more...

In this paper we discuss the possibilities of acting on psychosocial risk (PSR) factors by modifying the way in which an organisation operates. On the basis of an ergonomic intervention in an insurance company, we were able to show that the health problems observed by the operators were mainly the result of their inability to produce work of quality. Next, our analy- ses revealed the links between poor perceived quality, production difficulties and the rigidity of the organisational structure. After setting up working groups to deal with production difficulties, we were able to identify and test an organisational form that was better adapted to managing day-to-day production constraints and which was ultimately better able to be attentive to individual difficulties which had given rise, in the long term, to intrapsychic conflicts. more...

Une action sur les rps necessite, si elle se veut efficace, de permettre une mise en debat sur le fonctionnement organisationnel de l’entreprise, la repartition des lieux et des circuits de decision. Cet article a pour objectif de presenter les enjeux theoriques et methodologiques que cela represente pour l’action ergonomique sur les rps. Dans un premier temps, nous proposons un cadre theorique qui nous permet de montrer que les ergonomes ont un role a jouer sur les rps. Pour cela, il est question de pouvoir mettre en lien la souffrance exprimee par les operateurs avec les difficultes de production emanant de defaillances organisationnelles, et plus particulierement les difficultes rencontrees par les salaries pour « bien faire leur travail ». Nous presentons alors un exemple d’intervention dans une entreprise de service pour etayer nos propos. Pour terminer, nous nous appuyons sur le concept de subsidiarite comme guide a la reflexion sur la conception organisationnelle pour les ergonomes. more...

In-plane Electronic Speckle Pattern Interferometry (ESPI) has been successfully used during tensile tests on SMA-treated (Surface Mechanical Attrition Treatment) and as-received 316L stainless steel in order to measure the strain rate field. The heterogeneity in the strain rate field can be observed from a stage of deformation which doesn’t coincide with the classic Considere’s criterion (dF = 0) for the diffuse neck initiation (or plastic instability). The initiation of this heterogeneity strongly depends on treatments undergone by the material. In this paper, a comparison was performed about the heterogeneity initiation of specimens SMATed during 30 min with 2 mm shot, 3 mm shot and a non-treated sample. The formation of the two slip band system until fracture of the tensile specimen was also studied. more...

El artículo estudia diferentes estrategias de control de corriente usadas en un filtro activo trifásico tetrafilar de conexión en paralelo. Los esquemas de control estudiados son los basados en la Modulación Delta, el control deadbeat y el regulador PI. La efectividad de los tres esquemas de control es evaluada al utilizar diferentes formas de onda y los resultados son comparados por medio del error instantáneo y de la raíz media cuadrática del error entre la corriente inyectada por el filtro activo y su referencia. Finalmente, el mejor controlador es aplicado en un prototipo experimental de filtro activo diseñado para compensar armónicos generados por una carga no lineal. more...

International audience; The thick cuticle covering and embedding the epidermal cells of tomato (Solanum lycopersicum) fruit acts not only as a protective barrier against pathogens and water loss but also influences quality traits such as brightness and postharvest shelf-life. In a recent study, we screened a mutant collection of the miniature tomato cultivar Micro-Tom and isolated several glossy fruit mutants in which the abundance of cutin, the polyester component of the cuticle, was strongly reduced. We employed a newly developed mapping-by-sequencing strategy to identify the causal mutation underlying the cutin deficiency in a mutant thereafter named gpat6-a (for glycerol-3-phosphate acyltransferase6). To this end, a backcross population (BC1F2) segregating for the glossy trait was phenotyped. Individuals displaying either a wild-type or a glossy fruit trait were then pooled into bulked populations and submitted to whole-genome sequencing prior to mutation frequency analysis. This revealed that the causal point mutation in the gpat6-a mutant introduces a charged amino acid adjacent to the active site of a GPAT6 enzyme. We further showed that this mutation completely abolished the GPAT activity of the recombinant protein. The gpat6-a mutant showed perturbed pollen formation but, unlike a gpat6 mutant of Arabidopsis (Arabidopsis thaliana), was not male sterile. The most striking phenotype was observed in the mutant fruit, where cuticle thickness, composition, and properties were altered. RNA sequencing analysis highlighted the main processes and pathways that were affected by the mutation at the transcriptional level, which included those associated with lipid, secondary metabolite, and cell wall biosynthesis. more...

Cette étude s’appuie sur une intervention ergonomique réalisée à la demande d’un établissement bancaire à la suite de difficultés rencontrées par des agents au moment du retour au travail après une longue absence. De nombreux travaux ont été menés au sujet des reprises de travail à la suite d’un problème de santé, mais ceux-ci ne constituent qu’une partie de ces situations. L’objectif de notre étude porte sur les situations de reprise du travail quelle que soit l’origine de l’absence dont il s’agira d’abord de montrer la diversité. Notre propos est basé sur l’analyse de 16 cas de reprise du travail après une absence de plus de trois mois.Nous avons choisi de considérer la reprise de travail comme une « trajectoire » débutant avant le moment de l’absence et se poursuivant après le retour au travail du salarié. Nous avons relevé trois grandes catégories d’absence et de processus de retour. Nous avons pu ainsi élargir les possibilités d’action tout au long de ce processus pour faciliter le retour au travail. Nous avons mis l’accent sur la gestion organisationnelle de la reprise de travail qui devrait impliquer quelques acteurs-clés : le médecin du travail, l’encadrement de proximité, le référent Ressources humaines et les représentants du personnel. This study is based on an ergonomic intervention conducted at the request of a bank due to difficulties encountered by employees who were returning to work after a long-term absence. Though many studies have been conducted about return-to-work following a health problem (accident or illness), the particular aim of this study was to identify the key factors needed to facilitate return-to-work whatever the reason for the absence. The study analysis focused on 16 cases of return-to-work after an absence of more than three months.We decided to consider return-to-work as a process beginning before the moment of the absence and continuing after the moment when the employee returned to the workplace. This allowed us to widen the possibilities of action all throughout this process. We identified three main categories of absence and return-to-work. We likewise emphasized the need for an organizational management of return-to-work which should involve a few key actors, namely : the occupational health doctor, immediate supervisors, Human Resources service, and workers’ representatives. Este estudio se apoya en una intervención ergonómica realizada a petición de un banco como resultado de las dificultades encontradas por los agentes al volver al trabajo después de una larga ausencia. Se han realizado muchos estudios acerca de la reanudación del trabajo después de un problema de salud, pero estos constituyen solamente una parte de estas situaciones. El objetivo de nuestro estudio se centra en el retorno al trabajo, independientemente del origen de la ausencia de la cual se mostrará primero su diversidad. Nuestro trabajo se basa en el análisis de 16 casos de retorno al trabajo después de una ausencia de más de tres meses. Elegimos considerar la reanudación del trabajo como una « trayectoria » que comienza antes del momento de la ausencia y que continúa después del retorno al trabajo del empleado. Identificamos tres categorías principales de ausencia y de procesos de retorno. De esta manera pudimos ampliar las posibilidades de acción a lo largo de este proceso para facilitar el retorno al trabajo. Nos centramos en la gestión organizacional de la reintegración al trabajo que debería involucrar a algunos actores claves : el médico ocupacional, los superiores inmediatos, el referente de Recursos Humanos y los representantes del personal. more...

The cell expansion phase contributes in determining the major characteristics of a fleshy fruit and represents two-thirds of the total fruit development in tomato (Solanum lycopersicum). So far, it has received very little attention. To evaluate the interest of a genomic scale approach, we performed an initial sequencing of approximately 1,200 cell expansion stage-related sequence tags from tomato fruit at 8, 12, and 15 d post anthesis. Interestingly, up to approximately 35% of the expressed sequence tags showed no homology with available tomato expressed sequence tags and up to approximately 21% with any known gene. Microarrays spotted with expansion phase-related cDNAs and other fruit cDNAs involved in various developmental processes were used (1) to profile gene expression in developing fruit and other plant organs and (2) to compare two growing fruit tissues engaged mostly in cell division (exocarp) or in cell expansion (locular tissue surrounding the seeds). Reverse transcription-polymerase chain reaction analysis was further used to confirm microarray results and to specify expression profiles of selected genes (24) in various tissues from expanding fruit. The wide range of genes expressed in the exocarp is consistent with a protective function and with a high metabolic activity of this tissue. In addition, our data show that the expansion of locular cells is concomitant with the expression of genes controlling water flow, organic acid synthesis, sugar storage, and photosynthesis and suggest that hormones (auxin and gibberellin) regulate this process. The data presented provide a basis for tissue-specific analyses of gene function in growing tomato fruit. more...

Version française de l'ouvrage : P. Falzon (2013). Ergonomie Constructive. PUF, France.Version esapgnole : P. Falzon (2016). Ergonomia Construtiva. Blucher, Brazil.; International audience; The environment and the individual do not constitute separate entities, isolated from - and forced to coexist with - one another. Instead, they are two elements that evolvejointly in a search for balance. These general considerations about the human condition apply to the world of work. The elements of the work environment are major determinants of the activity of the individuals involved. They are also targets, in the sense that the environment is an object of transformation for the individual. Within these determinants, organizations have, over the past few years, been the subject of much attention on the part of ergonomists, since it remains a source of influence and a major target for the activity. Because of this, organizations have become an object of study and transformation for ergonomists. To specify, this text will argue that ergonomie action can be viewed, on the one hand, as a transformation of the organization, and on the other hand, as an opportunity to influence the development of individuals.In more concrete terms, in this chapter we will describe the course of an ergonomie intervention, its results and the reflections it led to. Over the course of this intervention, which was centred around an organi­ zational change, we had the opportunity to set up an 'experimentation' that allowed us to solve the actual problems of work and to construct the forms of collaboration that were necessary to solving these problems. This allowed us to identify sorne essential features in order to structure a system for the ergonomie intervention. We organized this system around moments where it was possible to define the rules of operation of work, and moments where more space was left for the development of individ­ ual and collective experience. This last point allows us to liken our method to an 'intrinsic approach' (Rabardel and Béguin, 2005)- an approach that is consistent with the personal points of view of the persons that make up the situation, that is, the workers themselves. This element seems crucial to us, since it allows individuals undergoing a process of organizational transition that is synonymous with cognitive and social disruptions to construct their own spaces for learning. By working on finding solutions to everyday difficulties related to their work, and attempting to construct a system that is as effective as possible for dealing with these problems, workers construct new representations of their current and future work. This allows us to open up two paths for reflection:• On the one hand, the running of the organization must be part of a developmental process, by allowing a joint evolution of the organi­ zational structure and of human activities.• On the other hand, an ergonomie intervention in organizational design may take place as part of this process more...

The cuticle is a protective layer synthesized by epidermal cells of the plants and consisting of cutin covered and filled by waxes. In tomato (Solanum lycopersicum) fruit, the thick cuticle embedding epidermal cells has crucial roles in the control of pathogens, water loss, cracking, postharvest shelf-life, and brightness. To identify tomato mutants with modified cuticle composition and architecture and to further decipher the relationships between fruit brightness and cuticle in tomato, we screened an ethyl methanesulfonate mutant collection in the miniature tomato cultivar Micro-Tom for mutants with altered fruit brightness. Our screen resulted in the isolation of 16 glossy and 8 dull mutants displaying changes in the amount and/or composition of wax and cutin, cuticle thickness, and surface aspect of the fruit as characterized by optical and environmental scanning electron microscopy. The main conclusions on the relationships between fruit brightness and cuticle features were as follows: (1) screening for fruit brightness is an effective way to identify tomato cuticle mutants; (2) fruit brightness is independent from wax load variations; (3) glossy mutants show either reduced or increased cutin load; and (4) dull mutants display alterations in epidermal cell number and shape. Cuticle composition analyses further allowed the identification of groups of mutants displaying remarkable cuticle changes, such as mutants with increased dicarboxylic acids in cutin. Using genetic mapping of a strong cutin-deficient mutation, we discovered a novel hypomorphic allele of GDSL lipase carrying a splice junction mutation, thus highlighting the potential of tomato brightness mutants for advancing our understanding of cuticle formation in plants. more...

La recherche sur la pratique en ergonomie fait l’objet de travaux depuis de nombreuses annees. L’objectif de cette recherche vise a proposer des generalisations concernant les demarches d’intervention des ergonomes, a partir de cas concrets. Nous souhaitons montrer que l’implication des ergonomes dans les projets de transformation du travail a evolue. Les ergonomes se sont construits une place indiscutable parmi les acteurs qui transforment le travail. Cela dit, il nous semble que deux facteurs majeurs obligent a penser differemment leur action. D’une part, les evolutions du monde du travail, avec notamment l’accroissement des activites de services et de nouvelles formes d’organisation, nous contraignent inevitablement a accentuer nos actions sur des determinants organisationnels. D’autre part, l’evolution des modeles de la sante nous permettent d’envisager celle-ci comme un construit, favorise par le developpement des individus et des collectifs : le developpement des operateurs au sein de leur environnement de travail devient ainsi un objectif en soi. A partir d’une intervention, nous essaierons de montrer que l’intervention ergonomique doit avoir un objectif double et des dispositifs associes 1) Favoriser l’experimentation organisationnelle a partir d’un travail collectif sur la gestion des difficultes de production. Ce dispositif sera envisage comme un moyen de developper les apprentissages sur le travail et sur la regulation organisationnelle. 2) Transformer la structure organisationnelle et des circuits decisionnels par un travail avec les decideurs. more...

Les problèmes de santé au travail trouvent souvent leur origine au cœur même de l’activité des opérateurs. L’intensification du travail, l’augmentation des contraintes, de la charge de travail physique, mentale et psychique et des injonctions contradictoires conduisent les salariés à faire des choix qui ne les satisfont pas toujours, pouvant être à la genèse de RPS et de TMS. Ce qui est en jeu c’est la qualité de leur travail, qui les rend uniques, qui les identifie comme de « bons professionnels » aux yeux des collègues, des clients et de la hiérarchie. Lorsque l’organisation empêche les opérateurs de faire du « bon travail », les risques sont des atteintes à leur santé physique et psychique. À partir d’une intervention dans le milieu bancaire, nous essaierons de montrer comment une réorganisation peut conduire les opérateurs à amputer une part « qualitativement significative » de leur activité et avoir des conséquences négatives sur le travail et la santé. Les perspectives ergonomiques envisageables en pareil cas sont d’agir sur l’organisation du travail. Health problems at work often originate in the operators’ activities. Work intensification, increasing pressures, greater physical, cognitive, and psychic workloads, and contradictory demands oblige employees to make choices which are not always satisfactory and which could be at the origin of their PSRs and MSDs. Good quality work, which makes them unique and identifies them as skillful professionals from their colleagues’, customers’, and management’s viewpoint, is at stake. When an organization prevents operators from doing a “good job,” the risks for their physical and psychic health increase. Based on an intervention in the banking sector, we try to show how reorganization can push operators to cut back on a “qualitatively significant” part of their activity and can have negative consequences on their work and health. In such a case, the most likely ergonomic options would be to try to change the organization. Los problemas de salud laboral suelen tener sus raíces en el seno mismo de la actividad de los operarios. La intensificación del trabajo, el aumento de las exigencias, de la carga de trabajo físico, mental y psíquico y la presencia de instrucciones contradictorias, llevan a los trabajadores a tomar decisiones que no siempre les satisfacen, pudiendo ser la génesis de la RPS y TME. Lo que está en juego es la calidad de su trabajo, que los hace únicos, identificándolos como "buenos profesionales" a los ojos de sus colegas, clientes y la jerarquía. Cuando la organización impide que los operadores realicen "un buen trabajo", existen riesgos de daños a su salud física y psíquica. A partir de una intervención en el sector bancario, trataremos de mostrar cómo una reorganización puede conducir a los trabajadores a amputar una parte "cualitativamente importante" de su actividad y tener un impacto negativo en su trabajo y su salud. El punto de vista de la ergonomía en estos casos es actuar sobre la organización del trabajo. more...

International audience; Tomato is currently the model plant for fleshy fruit development and for Solanaceae species. Recent genomic approaches including transcriptome, proteome and metabolome analyses and genetic mapping have produced a wealth of candidate genes whose function needs to be assessed. The recent development in model and crop plants of TILLING (Targeting Induced Local Lesions IN Genomes), which reveals allelic series corresponding to several independent point mutations, and the current availability of deep sequencing tools further increase the interest of generating artificially-induced genetic diversity in tomato. We describe here the generation and use of EMS (ethyl methanesulfonate) tomato mutants in the miniature cultivar Micro-Tom and provide as example the identification of new fruit size and morphology mutants. We further propose new deep sequencing-based strategies for the discovery of mutations underlying phenotypic variations observed in mutant collections that will considerably increase the interest of exploiting Micro-Tom mutant collections for gene discovery in tomato. more...

International audience; There is an urgent need in low cost and fast technologies that enable the exploration of natural or induced biodiversity in plants. Biochemical phenotyping is often considered as particularly promising to identify given analytes that are linked to desirable plant phenotypes and that could be used as markers for plant performance. Over the past 15 years, metabolomics and other omics approaches have been intensively used to study plant phenotypes. Still, they do not enable routine screens of very large populations in breeding programs, probably because this would represent unaffordable financial investments for equipment and specialised engineers. Along the last century, biochemical phenotyping and -screening have nevertheless been successfully exploited in medicine, pharmaceutical research and agro-industry. In medicine, over 6000 biochemical procedures exploiting a large variety of concepts and equipment are available for routine diagnosis and therapeutic monitoring. Pharmaceutical companies have spent massive investments to screen for biologically active molecules, whereas in the agro-industry increasingly sophisticated biochemical analysis has been developed to control the quality of raw and transformed products. Microplate technology is a well-established technology, which originated from the medical field and benefited from huge investments by the pharmaceutical industry. It offers the possibility to operate a wide range of analyses at very low costs per sample in plant research. To illustrate the potential of microplate technology as a high-throughput phenotyping tool, a screen for tomato metabolic mutants is shown where 24 enzymatic traits have been measured in more than 1500 samples within only 1 month with a relatively small investment. more...

International audience

En 2007, afin de renforcer et d’elargir l’action medicale, le service de sante au travail du CHU de Bordeaux s’est engage dans la pluridisciplinarite avec l’introduction d’une competence en psychologie de la sante au travail. Depuis l’hygiene et securite, l’ergonomie et l’epidemiologie sont venues elargir le champ disciplinaire et d’action de l’equipe, bien avant l’evolution recente des textes reglementaires qui prevoient cette pluridisciplinarite dans la fonction publique hospitaliere. Une posture reflexive constante, assuree avec les medecins sur l’activite de chacun, a permis de formaliser une charte sur la prevention et la gestion des RPS puis une seconde sur les missions de l’equipe pluridisciplinaire. En 2012, a la faveur de l’obtention d’un contrat local d’amelioration des conditions de travail (CLACT) sur la prevention conjointe des troubles musculo-squelettiques et des risques psychosociaux, une methodologie d’intervention en binome ergonome et psychologue en sante au travail a ete eprouvee. Dans le cadre de ce dispositif, l’equipe pluridisciplinaire a beneficie d’une analyse des pratiques animee par l’equipe d’ergonomie des systemes complexes de Bordeaux-institut polytechnique de Bordeaux (INP) au rythme d’environ une seance par bimestre. Ces seances presentaient un double enjeu. Le premier etait de mettre en debat les logiques disciplinaires, a travers les pratiques professionnelles, entre hygiene et securite, ergonomie et psychologie puis de les articuler avec celle de la responsabilite et du pilotage medical. Le second etait de consolider une organisation de travail en equipe permettant la construction d’un veritable collectif de travail pluridisciplinaire pilote par les medecins du travail. Dans ce sens, deux modalites organisationnelles ont ete posees. Tout d’abord, la mise en place de staffs mensuels dans lesquels les intervenants en prevention des risques professionnels (IPRP) et medecins du travail de secteur debattent des demandes et s’entendent sur une conduite a tenir. Puis a ete creee une mission de coordination de l’equipe IPRP assuree par le membre le plus ancien de l’equipe pluridisciplinaire. Enfin, institutionnellement, la mise en place d’une cellule sante travail animee par la Direction des ressources humaines et impliquant les instances representatives du personnel, a permis a la reflexion–action du service de sante au travail de s’inscrire dans un contexte favorable au developpement et a la reussite de cette pluridisciplinarite. Ce travail d’equipe permet au service de sante au travail de mieux repondre a ses missions, par le renforcement de l’expertise medicale et le developpement des actions sur le terrain tant sur le plan individuel que collectif. more...

La pratique de l’ergonomie est un champ de recherche qui permet depuis une vingtaine d’années, de produire des connaissances utiles à l’élaboration de démarches d’intervention et, par conséquent, utiles à la formation des ergonomes. À partir d’un modèle décrivant les registres possibles de l’échange en pédagogie, et insistant sur les liens possibles entre l’intervenant, les apprenants et les savoirs, nous tentons de montrer l’intérêt de puiser dans le creuset des sciences de l’éducation pour comprendre et structurer des démarches d’intervention en ergonomie. Sur la base de 3 interventions différentes, les résultats que nous obtenons nous permettent, non seulement, d’admettre qu’il existe une dimension pédagogique dans l’intervention ergonomique, mais aussi, d’explorer des possibilités de structurer l’intervention compte tenu des objectifs pédagogiques que l’on pourrait se fixer en tant qu’ergonome. Ergonomics is a field of research that has, for about twenty years, produced knowledge useful for the development of intervention models and, consequently, useful for the training of ergonomists. From a model describing the possible pedagogical exchange registers, and emphasizing the possible links between the instructor, the learners and the types of knowledge, we attempt to show the interest in drawing from concepts of education sciences in order to understand and structure ergonomic intervention processes. The cases of 3 different interventions are presented. The results that we obtain allow us, first, to acknowledge that there is an educational dimension in ergonomic intervention, but also, to investigate possibilities of structuring the intervention, considering the educational objectives that we could set for ourselves as ergonomists. La práctica de la ergonomía es un campo de investigación que permite desde hace una veintena de años, producir conocimientos útiles a la elaboración de procesos de intervención y, por consiguiente, útiles para la formación de los ergónomos. A partir de un modelo que describe les registros posibles del intercambio en pedagogía, e insistiendo en los lazos posibles entre la persona que hace la intervención, los aprendices y los saberes, intentamos mostrar el interés de utilizar conceptos provenientes de las ciencias de la educación para comprender y estructurar los pasos de la intervención ergonómica. En base a tres intervenciones diferentes, los resultados que obtenemos permiten, no solamente, admitir que existe una dimensión pedagógica en la intervención ergonómica, sino también explorar las posibilidades de estructurar la intervención teniendo en cuenta los objetivos pedagógicos que podríamos fijarnos como ergónomos. more...

International audience; This article presents a training course in work analysis via an understanding of real work. The course was aimed at trade unionists and was produced by researchers in ergonomics and occupational medicine. Designing this type of training is closely associated with the history of ergonomics in France and goes back to the basic principles: training by and for action, focusing on the concept of activity and the co-construction of knowledge, involving all actors in the relevant area of work. Participants: One hundred and fifty trade unionists were trained over a period of 18 months, successfully completing company projects in the field of occupational health. Methods: The course was organised into seven 3-day modules. Each module included plenary sessions on fundamental topics relating to health/work, and small work groups where the trade union projects were prepared, based on gaining an understanding of the real work involved. Results: There were two types of results: an understanding of the way work is currently changing and of the consequences of these changes for workers' health; transformations in trade unionists' representations of work, giving them a better awareness of health/work relationships, new ways of transforming work, and also information about the teaching content required when designing training programmes for trade unionists. Conclusion: Understanding the notion of activity and constructing interaction with employees are crucial elements for carrying out this type of project successfully. more...

Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699; The PIN-FORMED (PIN) auxin efflux transport protein family has been well characterized in the model plant Arabidopsis thaliana, where these proteins are crucial for auxin regulation of various aspects of plant development. Recent evidence indicates that PIN proteins may play a role in fruit set and early fruit development in tomato (Solanum lycopersicum), but functional analyses of PIN-silenced plants failed to corroborate this hypothesis. Here it is demonstrated that silencing specifically the tomato SlPIN4 gene, which is predominantly expressed in tomato flower bud and young developing fruit, leads to parthenocarpic fruits due to precocious fruit development before fertilization. This phenotype was associated with only slight modifications of auxin homeostasis at early stages of flower bud development and with minor alterations of ARF and Aux/IAA gene expression. However, microarray transcriptome analysis and large-scale quantitative RT-PCR profiling of transcription factors in developing flower bud and fruit highlighted differentially expressed regulatory genes, which are potential targets for auxin control of fruit set and development in tomato. In conclusion, this work provides clear evidence that the tomato PIN protein SlPIN4 plays a major role in auxin regulation of tomato fruit set, possibly by preventing precocious fruit development in the absence of pollination, and further gives new insights into the target genes involved in fruit set. more...

L'article original est publié par The American Society of Plant Biologists Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699; International audience; The plant cuticle consists of cutin, a polyester of glycerol, hydroxyl, and epoxy fatty acids, covered and filled by waxes. While the biosynthesis of cutin building blocks is well documented, the mechanisms underlining their extracellular deposition remain unknown. Among the proteins extracted from dewaxed tomato (Solanum lycopersicum) peels, we identified GDSL1, a member of the GDSL esterase/acylhydrolase family of plant proteins. GDSL1 is strongly expressed in the epidermis of growing fruit. In GDSL1-silenced tomato lines, we observed a significant reduction in fruit cuticle thickness and a decrease in cutin monomer content proportional to the level of GDSL1 silencing. A significant decrease of wax load was observed only for cuticles of the severely silenced transgenic line. Fourier transform infrared (FTIR) analysis of isolated cutins revealed a reduction in cutin density in silenced lines. Indeed, FTIR-attenuated total reflectance spectroscopy and atomic force microscopy imaging showed that drastic GDSL1 silencing leads to a reduction in ester bond cross-links and to the appearance of nanopores in tomato cutins. Furthermore, immunolabeling experiments attested that GDSL1 is essentially entrapped in the cuticle proper and cuticle layer. These results suggest that GDSL1 is specifically involved in the extracellular deposition of the cutin polyester in the tomato fruit cuticle. more...

International audience; Tomato fruit growth and composition depend on both genotype and environment. This paper aims (i) at studying how fruit phenotypic responses to changes in carbon availability can be influenced by genotype and (ii) at identifying genotype-dependent and -independent changes in gene expression underlying variations in fruit growth and composition. To this end, we grew a parental line (S. lycopersicum) and an introgression line from S. chmielewskii harboring QTL for fresh weight and sugar content under two fruit loads (FL). Lowering fruit load increased fruit cell number and reduced fruit developmental period in both genotypes. In contrast, fruit cell size was increased only in the parental line. Modifications in gene expression were monitored in expanding fruits using microarrays and RT-qPCR for a subset of genes. FL changes induced more deployments of regulation systems (transcriptional and post transcriptional) than massive adjustments of whole primary metabolism. Interactions between genotype and FL were especially noticeable for 99 genes mainly linked to hormonal and stress responses, and on gene expression kinetics during fruit development. Links between gene expression and fruit phenotype were found for aquaporin expression levels and fruit water content, and invertase expression levels and sugar content during fruit ripening phase. In summary, the present data emphasized age- and genotype-dependent responses of tomato fruit to carbon availability, at phenotypic as well as at gene expression level. more...

International audience; Very few reports have studied the interactions between ascorbate and fruit metabolism. In order to get insights into the complex relationships between ascorbate biosynthesis/recycling and other metabolic pathways in the fruit, we undertook a fruit systems biology approach. To this end, we have produced tomato transgenic lines altered in ascorbate content and redox ratio by RNAi-targeting several key enzymes involved in ascorbate biosynthesis (2 enzymes) and recycling (2 enzymes). In the VTC (ViTamin C) Fruit project, we then generated phenotypic and genomic (transcriptome, proteome, metabolome) data from wild type and mutant tomato fruit at two stages of fruit development, and developed or implemented statistical and bioinformatic tools as a web application (named VTC Tool box) necessary to store, analyse and integrate experimental data in tomato. By using Kohonen's self-organizing maps (SOMs) to cluster the biological data, pair-wise Pearson correlation analyses and simultaneous visualization of transcript/protein and metabolites (MapMan), this approach allowed us to uncover major relationships between ascorbate and other metabolic pathways. more...

The original and significant achievement of this work is to analyse strain rate field in aluminium alloy sheets during micro tensile test. In-plane Electronic Speckle Pattern Interferometry is used to follow the evolution of the local strain in real time. This paper is based on the detection of the localization on a relatively small area of the analysed specimen: less than 5mm × 4mm area. Moreover the speed of the tensile machine is very low, 0.2 to 0.1µm/s. The phase shifting technique is used to obtain the fringes representative of the material displacement. We can therefore get a very good accuracy in the material displacement. A heterogeneity in strain rate field can be noticed from a deformation stage which doesn’t coincide with the one calculated by the classic Considère’s criterion (dF=0) for the diffuse neck initiation (or plastic instability). We also show, the moment when one of the two slip bands systems becomes predominant, and even only one band continues to exist, this occurring widely before fracture. Finally, the fracture of the specimen occurs across this remaining band. The total strain is measured with a second camera, in white light, and is correlated together with the strain rate field to study the localization. more...