L'agentivité des artefacts dans les interactions comme observable de la dynamique organisationnelle

International audienceObserving artifacts' agency inside interactions to study organizational change The present proposal is part of a wider research pro gram to analyze and understand rationalization pro cesses at work in medical activities. the approach to observing these processes concerns those technolo gical devices that equip them in a communicational approach of the organization within a work group. The purpose of this proposal is to describe and analyze how rationalization processes appear as emerging practices of professional nursing activity, strengthe ning the focus on the mobilization of artifactsof va rious kinds. emphasis will be placed on professional practices involved in the performance of the organi zation emerging from the introduction of information technology tools in the care activities performed by nurses. We will discuss the recourse to these artifacts in the activities, in order to describe social transforma tion processes operating. our team collected data from ethnographical observation sessions in different departments of the same hospital, and from inter views with health care professionals. From this data, we will show how the reconstruction of the organiza tion through interactions can question the negotiation of norms by observing socio-technical mediations. Communication approach of organizations to think organizational change To study the processes of ra tionalization of productive activity in the health sector and, more particularly, in public hospitals, is to ques tion the translation of economic policy - including the development based on political decisions to scale of a country - in procedures and practices in the lives of the caregivers. Such a project involves a theoretical apparatus to analyze organizational restructuring, es pecially by determining access points to observation. Communication approach of organizations (Bouillon et al., 2008) propose to study organizational dyna mics by linking three perspectives, three levels wich intersect, and allow the organization to clarify " in the making ", i.e. " organizing ". The ideological dimen sion (production of speech), procedural dimension (setting procedures of the activity), and situational dimension (communication situations) open corres ponding methodological access points for the study of communication phenomena, to better understand organizing and organizational change. We propose in this contribution to access organizing by the situatio nal dimension of interactions. We will operate a further restriction in this dimension by giving a central place to " non humans " and their capacity to contribute to action, in other words, their agency. Communication approach of organizations and norms The question of the emergence of new norms in the organization can be studied in different ways. one possible way of viewing this issue is based on questionning the terms of appearance of norms in negotiation situations that are writing practices. traces produced during these situations should be viewed " as key elements to look to capture fluctuation and instability of social norms in which the installation requires communica tion and phenomena of social construction of reality. " (Bouillon et al., 2007). the authors invite us to view professional objects mobilized in activity as research objects, and to study how these translate into actions. observing the objects, their agency and assembling the socio-technical collective By giving prominence to studying non-humans in social sciences, we follow the proponents of the actor-network sociologists. in so doing, we recognize that what we call " social " is materially heterogeneous, and that " the entities who compose collectives are the result of linking, of asso ciations of heterogeneous materials. " (Callon and law, 1997, p.104). Human actors, in this theoretical framework, reconstruct the collective locally through the interactions, with other heterogeneous entities as humans, artifacts and texts, for example. the metho dological entry point that we choose, namely the communication situations observation, let us see how actors adjust and actualize the knowledge individual ly and collectively to achieve organization perfor mance, and therefore, performance of the collective. it is in these communication situations that translations wich contribute to the molding of the collective are performed. This occurs by the tacit actualization of organization's surroundings during transformation into practices of prescribed activity, constituting the reby precondition for action. our study aims to clarify mediated interactions, and the mobilization of various objects in the implementation of action, by attemp ting to trace the agencies intersecting and forming the organization. Writing for others : the collective activity programing, objects' agency in all three orders of reality covered by the communication situa tions (Bourdin, 2008), each conceptually separate but necessarily interlinked at the same time, we can determine different classes of field observations. We keep these observable field elements as they allow us to understand non-human's intervention in the course of the action. With such an equipment for analyzing, we are able to highlight the significant mobilization of artifacts with various ontologies, participating to put organization into action, where organization is under stood as a " plenum of agencies " (Cooren, 2010). In the form of writing practices on objects mobilized through action, we witness a collective programing of common actions. this category of writing practices seems particularly interesting for us, in that it creates a modality of collective programing of action, parallel to the one scripted in the dedicated software, for this purpose. these practices are constituting a mediation to use the physical environment as a communication way. They also contributes to the organization perfor mance into interactions. these objects are equiped with an extra informational layer, which is contextua lized within the " framework of the joint action " of the nurses (Bourdin, 2008), and allows them to pro ject this inscription work into performativities that has been planned during these inscriptions. the analysis of traces of these communication situations seems rele vant to reflect the transformation processes at work in organization understood as an " intermediate level of social structuration " (Bourdin, 2008).Université de toulouse III - Paul Sabatier - IUT de Tarbes - France Rationalisation des activités médicales : l'organi sation sous tension la proposition s'inscrit dans un programme de recherches visant à analyser et com prendre les processus de rationalisation à l'œuvre dans les activités médicales. La démarche d'observa tion de ces processus de rationalisation vise particuliè rement les dispositifs technologiques qui les équipent, dans une approche communicationnelle de l'orga nisation au sein d'un collectif de travail. L'objet de la présente proposition sera de décrire et analyser comment se manifestent les processus de rationali sation tels qu'ils émergent des pratiques des profes sionnels dans l'activité de soins infirmiers, en resserrant la focale sur la mobilisation d'artefacts de natures diverses. L'accent sera mis sur les pratiques profession nelles participant à la performance de l'organisation émergeant de l'introduction des outils informatiques dans les activités de soins pratiquées par les person nels infirmiers. Ce recours aux outils dans le cadre de l'activité sera discuté de façon à catégoriser les processus de transformations sociales à l'œuvre. À l'aide des données rassemblées par l'équipe lors de sessions d'observation de type ethnographique dans différents services d'un même institut de soins hos pitalier, et d'entretiens avec des professionnels de santé, nous montrerons comment la reconstitution de l'organisation dans les interactions permet de ques tionner la négociation des normes par les médiations socio-techniques observables. Les approches communicationnelles des organisations pour penser le changement organisationnel. Étudier les proces sus de rationalisation de l'activité productive, dans le secteur de la santé et plus particulièrement des structures hospitalières, revient à s'interroger sur la traduction des logiques d'orientation économique - dont l'élaboration repose sur des décisions politiques à l'échelle d'un pays - en procédures et en pratiques, dans le quotidien des soignants. Un tel projet implique un appareillage théorique permettant d'analyser les reconfigurations organisationnelles par l'identification d'observables, en particulier. les approches commu nicationnelles des organisations (Bouillon et al., 2008) proposentd'étudier la dynamique organisationnelle en articulant trois perspectives, trois niveaux qui tra versent et permettent d'expliciter l'organisation " en train de se faire ". la dimension idéologique (produc tion de discours), la dimension processuelle (mise en procédures de l'activité), et la dimension située (les situations de communication) ouvrent autant de points d'entrée méthodologiques permettant, par l'étude des phénomènes de communication, de sai sir l'organisation et le changement organisationnel. il sera proposé ici de rentrer dans l'organisation par la dimension située des interactions, en effectuant une restriction supplémentaire dans celle-ci, où l'on donnera une place centrale aux " non-humains " et à leurs capacités d'action. Les approches com municationnelles des organisations et les normes la question de l'apparition de nouvelles normes dans l'organisation peut être étudiée de différentes façons. Une des entrées possibles dans cette problématique repose sur l'interrogation des modalités d'apparition des normes dans les situations de négociation que constituent les pratiques d'écriture. les traces pro duites lors de ces situations sont à retenir, " comme éléments majeurs à observer pour saisir la fluctuation et l'instabilité des normes sociales dont l'installation passe par la communication et des phénomènes de construction de la réalité sociale. " (Bouillon et al., 2007). Les auteurs invitent à observer les objets profes sionnels comme des objets de recherche, et à étudier leur déclinaison en actions. Observer les objets, leur agentivité et les modalités d'assemblage du col lectif socio-technique Donner une place de choix à l'étude des non-humains dans les Sciences Humaines et Sociales, c'est faire droit aux tenants de la sociolo gie de l'acteur-réseau, en reconnaissant que ce que l'on nomme le " social " est matériellement hétéro gène, et que " les entités qui composent les collectifs sont le résultat de mises en relation, d'associations de matériaux hétérogènes " (Callon et law, 1997, p.104). les acteurs humains, dans ce cadre théorique, re construisent le collectif localement dans l'interaction, avec d'autres entités hétérogènes (humains, arte facts, textes, ...). l'entrée méthodologique choisie, à savoir l'observation des situations de communica tion, donne à voir comment les individus ajustent et actualisent individuellement et collectivement les connaissances permettant la réalisation de l'organi sation, et donc du collectif. C'est dans les situations que sont réalisées les traductions contribuant à la formation du collectif, par l'actualisation tacite des cadres de l'organisation lors de la mise en pratiques de l'activité prescrite, et constitue ainsi le préalable permettant l'action. notre objet d'étude s'attache à éclairer les interactions médiatisées, et la mobilisation de différents objets dans la réalisation de l'action, tout en tentant de tracer les agentivités traversant et formant l'organisation. Écrire pour les autres : pro grammation de l'activité collective et objets agissants Dans les trois ordres de réalité recouverts par les situa tions de communication (Bourdin, 2008), distingués conceptuellement mais nécessairement intriqués, nous pouvons déterminer différentes classes d'obser vables de terrain permettant de saisir l'intervention des non-humains dans le cours de l'action. Équipés d'un tel prisme d'analyse, nous avons pu souligner la mobilisation importante d'artefacts aux ontologies variées, participant de la mise en actes de l'organi sation, entendue comme un " plénum d'agentivités " (Cooren, 2010). Sous la forme de pratiques d'écri tures à même les objets mobilisés dans l'action, nous assistons à une programmation collective commune des actions. Cette catégorie de pratiques d'écriture nous semble particulièrement intéressante dans ce qu'elle crée un canal de programmation de l'action collective parallèle à celui inscrit dans l'application dédiée à cet usage. Ces pratiques constituent une médiation permettant d'utiliser l'environnement ma tériel de l'action comme canal de communication et constituent une performance de l'organisation dans les interactions. Les objets ainsi équipés d'un surplus in formationnel contextualisé dans les cadres communs de l'action des infirmiers permettent de projeter le travail d'inscription dans des performativités prévues lors de ces inscriptions. L'analyse des traces de ces situations de communication nous semble pertinente pour rendre compte des processus de transforma tion à l'œuvre dans l'organisation entendue comme un " niveau intermédiaire de structuration du social " (Bourdin, 2008)

Learning Optimal Control of Synchronization in Networks of Coupled Oscillators using Genetic Programming-based Symbolic Regression

Networks of coupled dynamical systems provide a powerful way to model systems with enormously complex dynamics, such as the human brain. Control of synchronization in such networked systems has far reaching applications in many domains, including engineering and medicine. In this paper, we formulate the synchronization control in dynamical systems as an optimization problem and present a multi-objective genetic programming-based approach to infer optimal control functions that drive the system from a synchronized to a non-synchronized state and vice-versa. The genetic programming-based controller allows learning optimal control functions in an interpretable symbolic form. The effectiveness of the proposed approach is demonstrated in controlling synchronization in coupled oscillator systems linked in networks of increasing order complexity, ranging from a simple coupled oscillator system to a hierarchical network of coupled oscillators. The results show that the proposed method can learn highly-effective and interpretable control functions for such systems.Comment: Submitted to nonlinear dynamic

Developing an understanding of the relationship between the durability of simplified and complex UK radioactive waste glasses

Safely disposing of radioactive waste glass within a geological disposal facility requires a thorough understanding of the kinetics and mechanisms of their aqueous dissolution over geological timescales. Whilst a significant number of studies have taken place on international waste glass compositions, major compositional differences between UK Magnox and international waste glasses render many of these studies inapplicable to UK Magnox glasses. Notably, one of the major compositional differences between UK and international glasses is the presence of Li. Further, the presence of excess Li concentrations in some UK vitrified products has meant the effects of Li on the aqueous durability of UK waste glasses needed to be investigated. Additionally, dissolution experiments commonly take place at a higher temperature than the expected temperature of groundwater within a geological disposal facility. As such, the effects of dissolution temperature on the mechanisms of dissolution was also investigated. As the Li contents of complex waste glasses cannot be varied, two seven-component analogues of molar Li:Na ratios of 1.0 and 1.5 based upon a 25 wt.% loading UK Magnox waste glass with and without excess Li contents were fabricated. After characterising these glasses, they were leached in a mechanistic study to investigate the effects of Li on chemical durability. In addition to 7Li MAS-NMR and 6Li-1H CP-NMR, comprehensive 11B and 23Na MAS-NMR studies and SEM imaging of the leached glass surfaces then took place to investigate the effects of dissolution on the structures of the glasses. Here we show that the proportion of IIIB to IVB units did not evolve as the Li:Na ratio was varied; suggesting that Na preferentially charge compensates the B network. However, the B network was shown to leach incongruently at 90 °C. Despite Li being shown to be detrimental to durability during the earlier dissolution regimes, the residual rates of alteration implied excess Li contents had no long-term effects on chemical durability. The observed incongruent dissolution of the B network and initially decreased chemical durability could be attributed to Li preferentially modifying the Si network, thereby promoting glass hydration and B network dissolution whilst the Na compensated IVB units were less affected than IIIB units. Additionally, Li and Na were shown to be incorporated into secondary phases at 90 °C, but these Na-bearing phases were not observed at 40 °C. To compare the effects of Li contents on international and UK waste glass compositions, Li was substituted for Na in the well-studied Li-free French analogue “International Simple Glass” at molar Li:Na ratios of 0.4 and 0.9. These fabricated glasses were then leached and characterised in the same manner as the Magnox waste glasses. It was shown that the IIIB/IVB ratio and the role of Na in the pristine glasses varied insignificantly with the Li:Na ratio. Further, the B network of these glasses was shown to leach congruently at both 40 and 90 °C. However, Li, Na and Mg were shown to not be incorporated into secondary phase precipitates for these glasses and the leached glass surfaces displayed only minimal evidence of surface alteration. Contrastingly, whilst Li was shown to be detrimental to aqueous durability, further substituting Li for Na improved long-term aqueous durability. This was attributable to a Li-Na mixed alkali effect which was not evident in the Magnox waste glasses. The effects of dissolution temperature on the kinetics and mechanisms of dissolution of Magnox waste glasses still needed to be investigated. As such, a Magnox waste glass of 25 wt.% simulant waste loading was leached in static batch experiments at 40, 70, 80 and 90 °C to investigate the Arrhenius dependence of dissolution. Leached samples were characterised by EDX, SEM and XRD. It was shown that changing the dissolution temperature changed the rate of hydrolysis relative to interdiffusion. At higher temperatures, the initial release of Na deviated from Arrhenius-type behaviour and instead displayed an almost flat Arrhenius plot; demonstrating changes in temperature affect Na differently to other glass species. Whilst the activation energies of the Li and B releases were in the range of a mixed reaction, the higher activation energy of Na at lower temperatures combined with its non-Arrhenius behaviour suggested the dissolution processes of Li and Na differed. These observations were attributed to the preference of Na to charge compensate the B network. These results highlighted a need for an additional dimension with which to probe the mechanisms by which glasses dissolve. As such, a simplistic proof of concept dissolution experiment took place at 90 °C on a simplified analogue of a complex waste glass to investigate whether the temporal evolution of the isotopic signatures of the glass leachates could provide information on glass dissolution mechanisms. Li, B and Mg isotope ratio analysis took place on the glass leachates. It was shown that dissolution was initially congruent but diffusive processes were rate limiting whilst the glass dissolved at its residual rate. These isotopic techniques were then applied to investigate the temperature dependence of dissolution of a complex Magnox waste glass. Contrastingly, it was shown that diffusive processes initially controlled dissolution but such diffusive processes were not visible at longer durations. These results suggested the same dissolution processes were taking place at both 40 and 90 °C.This work was supported by EPSRC under an Industrial CASE award with the Nuclear Decommissioning Authority (NDA) and Radioactive Waste Management (RWM) (Grant Ref: EP/M507350/1)

Sur la cristallinité des biotites kaolinitisées des sols ferrallitiques de la région d'Ambalavao (Madagascar)

Cet article présente une étude minéralogique des "kaolinites" des sols ferrallitiques de la région d'Ambalavao. Suite aux analyses effectuées, les auteurs montrent qu'il s'agit de kaolinites désordonnées et de composés amorphes de même composition chimique. Ils supposent que l'abaissement d'enthalpie libre de formation de ces composés amorphes par rapport à celle de la kaolinite pourrait être à l'origine de leur transformation en gibbsite même en présence de quart

A new family of extended Gauss quadratures with an interior interval constraint

AbstractStarting from two sequences {Ĝa,c,n} and {Ĝd,b,n} of ordinary Gauss quadrature formulae with an orthogonality measure dσ on the open intervals (a,c) and (d,b), respectively. We construct a new sequence {Ĝa,b,e(n)} of extended Gaussian quadrature formulae for dσ on (a,b), which is based on some preassigned points, the nodes of Ĝa,c,n, Ĝd,b,n and the e(n) zeros contained in (c,d) of a nonclassical orthogonal polynomial on [a,b] with respect to a linear functional. The principal result gives explicit formulae relating these polynomials and shows how their recurrence coefficients in the three-term recurrence formulae are related. Thus, a new class of Gaussian quadratures, having some nodes contained in a given interior interval, can be computed directly by standard software for ordinary Gauss quadrature formulae

Segmentation of complex geophysical structures with well data

International audienceIn many problems of geophysical interest, when trying to segment images (i.e., to locate interfaces between different regions on the images), one has to deal with data that exhibit very complex structures. This occurs, for instance, when describing complex geophysical images (with layers, faults,...); in that case, segmentation is very difficult. Moreover, the segmentation process requires to take into account well data to interpolate, which implies integrating interpolation condition in the mathematical model. More precisely, let I: Ω --> R be a given bounded image function, where Ω is an open and bounded domain that belongs to Rn. Let $S= {x_i}_i$ ∈ Ω be a finite set of given points (well data). The aim is to find a contour Γ ⊂ Ω such that Γ is an object boundary interpolating the points from S. To do that, we combine the ideas of the geodesic active contour (Caselles et al., Int. J. Comput. Vision 22-1:61-87, 1997) and of interpolation of points (Zhao et al., Comput. Vis. Image Understand. 80:295-314, 1986) in a Level Set approach developed by Osher and Sethian (J. Comput. Phys. 79:12-49, 1988). We present modelling of the proposed method. Both theoretical results (viscosity solution) and numerical results (on a velocity model for a real seismic line) are give

Magnetic Phase Transitions in NdCoAsO

Magnetization measurements reveal that NdCoAsO undergoes three magnetic phase transitions below room temperature. The crystal and magnetic structures of NdCoAsO have been determined by powder neutron diffraction, and the effects of the phase transitions on physical properties are reported. Near 69 K a ferromagnetic state emerges with a small saturation moment of about 0.2 Bohr magnetons, likely on Co atoms. At 14 K the material enters an antiferromagnetic state with propagation vector (0 0 1/2) and small ordered moments (~0.4 Bohr magnetons) on Co and Nd. Near 3.5 K a third transition is observed, and corresponds to the antiferromagnetic ordering, with the same propagation vector, of larger moments on Nd reaching 1.30(2) Bohr magnetons at 1.4 K. In addition, transport properties and heat capacity results are presented, and show anomalies at all three phase transitions.Comment: Some minor changes made, and lower temperature neutron diffraction results are included. Accepted for publication in Physical Review