311 research outputs found

    Processus d'individuation, éthique et pragmatisme. A la recherche de fondements théoriques pour appréhender la firme partenariale

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    38 p.This article aims at providing a new stakeholder theory of the firm which overcomes the limits of the main approach that is generally mobilised to understand the modern corporation : the property rights approach. It is argued that the theoretical foundations provided by the pragmatism appear to be very useful to understand the ethical behaviour of social actors when the decision process is distributed : by insisting on the process of individuation that arises when the situation becomes "problematic", this approach succeeds in taking into account the building of principles of justice between actors of a same corporation.Cet article vise à fournir une appréhension renouvelée de la firme partenariale en partant des divers travaux existants et en les soumettant à une analyse critique, tant du point de vue de la caractérisation empirique de l'objet traité que de son appréhension théorique. La thèse défendue est que le recours à l'approche pragmatique ouvre d'intéressantes perspectives afin de surmonter les insuffisances dont témoigne la théorie des droits de propriété, principale théorie mobilisée afin d'appréhender la firme partenariale. On montre en particulier que les fondations théoriques sur lesquelles s'est construite l'approche pragmatique permettent de rendre compte de comportements "éthiques" : en insistant sur le nécessaire processus d'individuation auquel donne lieu toute situation "problématique", cette approche invite à mettre l'accent sur la construction -de manière endogène et concertée- de principes de justice entre acteurs participant à un même processus de décision

    Processus d'individuation, éthique et pragmatisme. A la recherche de fondements théoriques pour une appréhension de la firme partenariale

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    Cet article vise à fournir une appréhension renouvelée de la firme partenariale en partant des divers travaux existants et en les soumettant à une analyse critique, tant du point de vue de la caractérisation empirique de l'objet traité que de son appréhension théorique. La thèse défendue est que le recours à l'approche pragmatique ouvre d'intéressantes perspectives afin de surmonter les insuffisances dont témoigne la théorie des droits de propriété, principale théorie mobilisée afin d'appréhender la firme partenariale. On montre en particulier que les fondations théoriques sur lesquelles s'est construite l'approche pragmatique permettent de rendre compte de comportements "éthiques" : en insistant sur le nécessaire processus d'individuation auquel donne lieu toute situation "problématique", cette approche invite à mettre l'accent sur la construction -de manière endogène et concertée- de principes de justice entre acteurs participant à un même processus de décision.partenariat ; entreprise ; droit de propriété ; prise de décision ; connaissance ; division du travail ; organisation de l'entreprise

    Olfactory signal coding in an odor background

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    AbstractInsects communicating with pheromones are confronted with an olfactory environment featuring a diversity of volatile organic compounds from plant origin. These volatiles constitute a rich and fluctuant background from which the information carried by the pheromone signal must be extracted. Thus, the pheromone receptor neurons must encode into spike trains the quality, intensity and temporal characteristics of the signal that are determinant to the recognition and localization of a conspecific female. We recorded and analyzed the responses of the pheromone olfactory receptor neurons of male moths to sex pheromone in different odor background conditions. We show that in spite of the narrow chemical tuning of the pheromone receptor neurons, the sensory input can be altered by odorant background

    A General Odorant Background Affects the Coding of Pheromone Stimulus Intermittency in Specialist Olfactory Receptor Neurones

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    In nature the aerial trace of pheromone used by male moths to find a female appears as a train of discontinuous pulses separated by gaps among a complex odorant background constituted of plant volatiles. We investigated the effect of such background odor on behavior and coding of temporal parameters of pheromone pulse trains in the pheromone olfactory receptor neurons of Spodoptera littoralis. Effects of linalool background were tested by measuring walking behavior towards a source of pheromone. While velocity and orientation index did drop when linalool was turned on, both parameters recovered back to pre-background values after 40 s with linalool still present. Photo-ionization detector was used to characterize pulse delivery by our stimulator. The photo-ionization detector signal reached 71% of maximum amplitude at 50 ms pulses and followed the stimulus period at repetition rates up to 10 pulses/s. However, at high pulse rates the concentration of the odorant did not return to base level during inter-pulse intervals. Linalool decreased the intensity and shortened the response of receptor neurons to pulses. High contrast (>10 dB) in firing rate between pulses and inter-pulse intervals was observed for 1 and 4 pulses/s, both with and without background. Significantly more neurons followed the 4 pulses/s pattern when delivered over linalool; at the same time the information content was preserved almost to the control values. Rapid recovery of behavior shows that change of perceived intensity is more important than absolute stimulus intensity. While decreasing the response intensity, background odor preserved the temporal parameters of the specific signal

    Mouthiers-sur-Boëme, Chez les Rois

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    Chez les Rois est un gisement de référence de l'Aurignacien charentais et un des rares gisements aurignaciens européens à avoir livré des restes humains en place. Fouillé entre 1930 et 1939 par Potut et entre 1948 et 1952 par Mouton et Joffroy (1958), ce gisement a fait l'objet d'un sondage en 2005 et d'une fouille programmée entre 2006 et 2008 (d'Errico et Vanhaeren 2005, 2006, 2007, 2008). Cette opération de terrain a fait suite à la reprise de l'étude des restes humains et du matériel archéologique issus des fouilles Mouton et Joffroy ainsi qu'à sa datation (Ramirez Rozzi et al. sous presse). L'objectif des nouvelles fouilles était de préciser l'attribution culturelle des assemblages, la chronologie et nature de l'occupation aurignacienne ainsi que l'affiliation taxinomique des groupes humains qui ont fréquenté le site

    Host shift induces changes in mate choice of the seed predator Acanthoscelides obtectus via altered chemical signalling

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    The mechanisms of host shift in phytophagous insects are poorly understood. Among the many proposed processes involved, sexual selection via semiochemicals has recently been suggested. This hypothesizes that sexual communication using pheromones is modified as a result of development on a new host, and such plant-induced phenotypic divergence in mate recognition cues can lead to reproductive isolation between host lines. We tested this hypothesis on Acanthoscelides obtectus, an oligophagous bruchid of Phaseolus vulgaris beans worldwide, which also develops in acceptable non-hosts, such as chickpea (Cicer arietinum L.). Male sex pheromone blends of the bean, chickpea and chickpea/bean host lines during artificially induced host shifts showed different composition. Bean-reared females did not distinguish between blends, whereas chickpea and chickpea/bean females preferred the chickpea male pheromone. However, electrophysiological (EAG) responses to male odour of antennae of the three female host lines were similar, all preferring bean-reared males. Egg-laying choice tests revealed a uniform preference for bean seeds across female host lines, even after multiple generations, whereas larvae did not distinguish between bean and chickpea seeds. We conclude that the development of divergent chemical signalling systems during host shifts does not facilitate the evolution of host races in A. obtectus, because oviposition preferences remain unaffected

    Identification and Behavioral Evaluation of Sex Pheromone Components of the Chinese Pine Caterpillar Moth, Dendrolimus tabulaeformis

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    Background: The Chinese pine caterpillar moth, Dendrolimus tabulaeformis Tsai and Liu (Lepidoptera: Lasiocampidae) is the most important defoliator of coniferous trees in northern China. Outbreaks occur over enormous areas and often lead to the death of forests during 2–3 successive years of defoliation. The sex pheromone of D. tabulaeformis was investigated to define its chemistry and behavioral activity. Methodology/Principal Findings: Sex pheromone was collected from calling female D. tabulaeformis by headspace solid phase microextraction (SPME) and by solvent extraction of pheromone glands. Extracts were analyzed by coupled gas chromatography/mass spectrometry (GC-MS) and coupled GC-electroantennographic detection (GC-EAD), using antennae from male moths. Five components from the extracts elicited antennal responses. These compounds were identified by a combination of retention indices, electron impact mass spectral matches, and derivatization as (Z)-5-dodecenyl acetate (Z5-12:OAc), (Z)-5-dodecenyl alcohol (Z5-12:OH), (5Z,7E)-5,7-dodecadien-1-yl acetate (Z5,E7-12:OAc), (5Z,7E)-5,7-dodecadien-1-yl propionate (Z5,E7-12:OPr), and (5Z,7E)-5,7-dodecadien-1-ol (Z5,E7-12:OH). Behavioral assays showed that male D. tabulaeformis strongly discriminated against incomplete and aberrant blend ratios. The correct ratio of Z5,E7-12:OAc, Z5,E7-12:OH, and Z5,E7-12:OPr was essential for optimal upwind flight and source contact. The two monoenes, Z5-12:OAc and Z5-12:OH, alone or binary mixtures, had no effect on behavioral responses when added to the optimal threecomponen
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