Enhanced visualization of polysaccharides from aqueous suspensions

Aqueous suspensions of polysaccharides such as those prepared for domestic and industrial applications or present in natural waters, although difficult to visualize by conventional transmission electron microscopy (TEM) because of their poor electron density, can be characterized at the ultrastructural level by using milden bloc staining and contrast enhancement by energy-filtered TEM (EF-TEM). The advantages and drawbacks of the proposed method are discussed in relation to the different parameters controlling the quality of final images. It is shown, with synthetic polysaccharides, purified algal fibrils and lacustrine exocellular polymers as key examples, that optimizing specimen preparation and visualization parameters allows unbiased identification of organic substructures never revealed or strongly degraded by classical microscopic procedure

Incertitude(s) et Stratégie(s)

Introduction au numéro spécial RFG-AIMS. Compilation de recherches francophones en management stratégique contribuant à la réflexion sur la manière dont cette discipline se saisit de l'incertitude contextuelle et générique.Stratégie - Incertitude -

Three cases of identity (re)construction through art interventions: the dialogical and the 'sensible'

Identity construction (IC) cannot be reduced to discourses, nor to individual responsibility. Alvesson & Wilmott (2002) suggest two main processes of identity construction : identity regulation (IR, the discursive practices of identity definition) and identity work (IW, the interpretive activities involved in reproduction of self-identity). Based on this dialogic conception of IC, we wonder whether artistic interventions could play a significant role in the IC process, especially through its ability to address the relational, sensible, emotional, and affective dimensions. In other words, our paper intends to better understand the role of experience and the embodiment of sensemaking in the dialogic process of identity construction. In this perspective, we will focus on cases where art interventions take place in working situations at some crucial moments of IC. Exploring the dimension of the sensible encapsulated in artworks and art interventions allows in particular to better grasp how collective understanding of organizations and their transformations hinge on subjectivity (Abrir 2012). This knowledge is generally recognized as disruptive, because of the heterogeneity of the two words of art and organization, the ability of art for ―not-knowing or more generally the ability of art and aesthetics for promoting contradictory emotions. The dimension of the sensible brought by art is characterized by its subjectification power and by its value sharing (the role of emotions and affects, the construction of subjectivity) and value-adding. Our argument is that art, by organizing the co-creation of work-related sensible forms, triggers and performs - in ways we strive at investigating - a collective and dialogic process between IR and IW

Mediating male-male interactions: the role of the UV-blue crest coloration in blue tits

This is the postprint version of the article. The published article can be located here: http://link.springer.com/article/10.1007/s00265-010-0995-z?nullBadges of status, usually color patches, are hypothesised to serve as important signals within natural populations by communicating individual’s fighting ability or aggressiveness before an interaction ever takes place. These signals, which may evolve via sexual and/or social selection, mediate intra-specific competition by influencing the outcome or escalation of contests between individuals. The last 10 years saw the rise of interest in the role of Ultraviolet (UV)-based coloration in intra-sexual communication. However, the rare experimental studies that tested this hypothesis found opposite results, which may originate from the different methodological procedures used to assess badge of status theory. We present here the results of an experiment testing whether male blue tits (Cyanistes caeruleus) respond differently to unfamiliar conspecifics presenting contrasted UV crest coloration. In an aviary, we simultaneously presented two caged blue tits with enhanced (UV+) or reduced (UV-) crest coloration to a focal bird. We found that focal males acted more aggressively towards the UV- males than UV+ males. In addition, focal males fed more often close to males that were similar in brightness or duller than themselves. We conclude that, in blue tits, UV-blue crest coloration affects both social and aggressive responses towards unfamiliar individuals, and thus it has some properties of a badge of status

An Art-Based, Collective and Dialogic Ethnographic method -Unveiling corporate restructuring practices

Restructuring practices belong to today's organizational life. Even if the phenomenon is not new it significantly evolved over time, both in terms of motives and in terms of expressions, from major events to permanent practices, from crisis to competitiveness restructurings, from reactive to more proactive decisions, from highly visible to more silent decisions. Much debated in popular medias, restructuring issues have been also inspiring scholars from various fields (sociology, economics, management, law...) for now three decades. But at the same time, academic literature, especially in management, has hardly contributed in understanding the deep complexity and the multiple hidden dimensions of restructuring situations. We suggest ethnographic studies could open the " black box " of restructuring issues, thus complementing the inevitably over-simplified models testing the explanatory relationships between a set of variables or constructs. Traditional ethnographic method is scarcely chosen by scholars analyzing restructuring issues, mainly for reasons related to practical access to fieldwork: restructuring is a hot issue, and it remains difficult to access information and informants in a restructuring organization. In order to overcome these issues, we developed a specific research method what we call an Art-Based, Collective and Dialogic Ethnographic method (1.), both in its deliberate choices (1.1.) and its emergent dimensions (1.2.). Then we describe the outputs of the method (2.), in terms of creating new knowledge about restructuring issues (2.1.), but also in terms of fostering new ways of teaching, thinking or practicing restructurings (2.2.). In the final section, we discuss the basic principles of the method as well as its outcomes, especially in terms of creating "vicarious experiential knowledge" (3.). This method is based on three main features. First, we suggest investigate restructuring issues through artworks. Second, as restructurings are multi-actor situations and multi-dimensional phenomena, research on restructurings could benefit from a heterogeneous and multi-disciplinary group of actors as a community of inquirers confronting their points of view and reflecting together about the complexity and the heterogeneity of restructuring phenomena in a dialogical process of investigation. Third, combining in the same research design a heterogeneous group of actors and a series of artworks about restructurings can lead to innovative research methods: collective comments about artworks and indirect analysis of restructuring, reflexive analysis of actors' involvement, comments and discussions used as data, what we propose here as a new form of organizational ethnographic research