Entrepreneuriat organisationnel : Enseignements stratégiques d'une approche comparée des principaux modèles

Ce travail effectue une étude comparative de différentes modélisations de l'entrepreneuriat organisationnel. Nous étudions ces modèles à travers des prismes différents, afin de mettre en lumière leurs similitudes et leurs différences, notamment dans leur manière de relier les notions de stratégie et d'entrepreneuriat. Cette étude s'inscrit dans une actualité brûlante, car des travaux récents (Lumpkin, 2009) ont souligné des faiblesses dans le construit d'orientation entrepreneuriale, sur lequel sont construits de nombreux modèles et un décalage entre le construit et les outils habituellement utilisés pour le mesurer. Elle apporte à la littérature une approche comparative originale des modélisations principales utilisées pour conceptualiser l'entrepreneuriat organisationnelentrepreneuriat organisationnel ; stratégie ; orientation entrepreneuriale; management entrepreneurial

Management entrepreneurial et orientation entrepreneuriale : deux concepts si differents ?

Le management entrepreneurial (Stevenson, 1983) peut-il être assimilé à l'orientation entrepreneuriale (Miller, 1983) concept développé et largement utilisé pour mesurer l'intensité entrepreneuriale d'une organisation ? Nous montrons que ces deux concepts sont distincts bien que conduisant tous deux vers l'entrepreneuriat organisationnel (Brown et al., 2001). Ensuite, nous conduisons une étude comparative des modèles d'entrepreneuriat organisationnel qui sont basés sur, ou intègrent, l'orientation entrepreneuriale (OE), afin d'identifier si les dimensions du management entrepreneurial peuvent être considérées comme des facteurs organisationnels affectant l'OE. Nous soulignons que le caractère dynamique de ce type d'entrepreneuriat appelle à des recherches qualitatives supplémentaires afin de donner un contenu au concept. Ceci permettrait, notamment, aux praticiens d'identifier les mécanismes et processus qui maintiennent l'intensité entrepreneuriale à un bon niveau et d'agir sur ces derniers quand cette intensité fait défaut. Ce contenu donnerait au monde académique un matériau pour réexaminer l'opérationnalisation de l'orientation entrepreneuriale, nécessité soulignée par Basso et al., (2009), et confirmée par Lumpkin et al., (2009)Management Entrepreneurial ; Orientation Entrepreneuriale ; entrepreneuriat organisationnel ; mode de management favorisant l'entrepreneuriat organisationnel

Management Entrepreneurial et Orientation Entrepreneuriale : Deux concepts aussi différents ?

Le management entrepreneurial (Stevenson et Gumpert, 1985) peut-il être assimilé à l'orientation entrepreneuriale (Miller, 1983 ; Covin et Slevin, 1988, 1989, 1991 ; Lumpkin et Dess, 1996), concept développé et largement utilisé pour mesurer l'intensité entrepreneuriale d'une organisation ? Nous démontrons que ces deux concepts sont distincts bien que conduisant tous deux vers l'entrepreneuriat organisationnel (Brown et al, 2001). Nous soulignons que le caractère dynamique de ce type d'entrepreneuriat appelle à des recherches qualitatives supplémentaires afin de donner un contenu au concept. Ceci permettrait, notamment, aux praticiens d'identifier les mécanismes et processus qui maintiennent l'intensité entrepreneuriale à un bon niveau et d'agir sur ces derniers quand cette intensité fait défaut. Ce contenu donnerait au monde académique un matériau pour réexaminer l'opérationnalisation de l'orientation entrepreneuriale, nécessité soulignée par Basso et al (2010).Management Entrepreneurial ; Orientation Entrepreneuriale; entrepreneuriat organisationne mode de management favorisant l'entrepreneuriat organisationnel

Molecular hydrogen uptake by soils in forest, desert, and marsh ecosystems in California

The mechanism and environmental controls on soil hydrogen (H_2) uptake are not well understood but are essential for understanding the atmospheric H_2 budget. Field observations of soil H_2 uptake are limited, and here we present the results from a series of measurements in forest, desert, and marsh ecosystems in southern California. We measured soil H_2 fluxes using flux chambers from September 2004 to July 2005. Mean H2 flux rates and standard deviations were −7.9 + −4.2, −7.6 + −5.3 and −7.5 + −3.4 nmol m^(−2) s^(−1) for the forest, desert, and marsh, respectively (corresponding to deposition velocities of 0.063 + −0.029, 0.051 + −0.036, 0.035 + −0.013 cm s^(−1)). Soil profile measurements showed that H_2 mixing ratios were between 3% and 51% of atmospheric levels at 10 cm and that the penetration of H_2 into deeper soil layers increased with soil drying. Soil removal experiments in the forest demonstrated that the litter layer did not actively consume H_2, the removal of this layer increased uptake by deeper soil layers, and the exposure of subsurface soil layers to ambient atmospheric H_2 levels substantially increased their rate of uptake. Similar soil removal experiments at the desert site showed that extremely dry surface soils did not consume H2 and that fluxes at the surface increased when these inactive layers were removed. We present a model of soil H_2 fluxes and show that the diffusivity of soils, along with the vertical distribution of layers that actively consume H_2 regulate surface fluxes. We found that soil organic matter, CO_2 fluxes, and ecosystem type were not strong controllers of H_2 uptake. Our experiments highlight H_2 diffusion into soils as an important limit on fluxes and that minimum moisture level is needed to initiate microbial uptake

Temperature and moisture dependence of soil H_2 uptake measured in the laboratory

The soil sink of molecular hydrogen is the largest and most uncertain term in the global atmospheric H_2 budget. Lack of information about the mechanisms regulating this sink limits our ability to predict how atmospheric H_2 may respond to future changes in climate or anthropogenic emissions. Here we present the results from a series of laboratory experiments designed to systematically evaluate and describe the temperature and soil moisture dependence of H_2 uptake by soils from boreal forest and desert ecosystems. We observed substantial H2 uptake between −4°C and 0°C, a broad temperature optimum between 20°C and 30°C, a soil moisture optimum at approximately 20% saturation, and inhibition of uptake at both low and high soil moisture. A sigmoidal function described the temperature response of H_2 uptake by soils between −15°C and 40°C. Based on our results, we present a framework for a model of the soil H_2 sink

Changes in the surface energy budget after fire in boreal ecosystems of interior Alaska: An annual perspective

Understanding links between the disturbance regime and regional climate in boreal regions requires observations of the surface energy budget from ecosystems in various stages of secondary succession. While several studies have characterized fire‐induced differences in surface energy fluxes from boreal ecosystems during summer months, much less is known about these differences over the full annual cycle. Here we measured components of the surface energy budget (including both radiative and turbulent fluxes) at three sites from a fire chronosequence in interior Alaska for a 1‐year period. Our sites consisted of large burn scars resulting from fires in 1999, 1987, and ∼1920 (hereinafter referred to as the 3‐, 15‐, and 80‐year sites, respectively). Vegetation cover consisted primarily of bunch grasses at the 3‐year site, aspen and willow at the 15‐year site, and black spruce at the 80‐year site. Annual net radiation declined by 31% (17 W m^(−2)) for both the 3‐ and the 15‐year sites as compared with the 80‐year site (which had an annual mean of 55 W m^(−2)). Annual sensible heat fluxes were reduced by an even greater amount, by 55% at the 3‐year site and by 52% at the 15‐year site as compared with the 80‐year site (which had an annual mean of 21 W m^(−2)). Absolute differences between the postfire ecosystems and the mature black spruce forest for both net radiation and sensible heat fluxes were greatest during spring (because of differences in snow cover and surface albedo), substantial during summer and winter, and relatively small during fall. Fire‐induced disturbance also initially reduced annual evapotranspiration (ET). Annual ET decreased by 33% (99 mm yr^(−1)) at the 3‐year site as compared with the 80‐year site (which had an annual flux of 301 mm yr^(−1)). Annual ET at the 15‐year site (283 mm yr^(−1)) was approximately the same as that from the 80‐year site, even though the 15‐year site had substantially higher ET during July. Our study suggests that differences in annual ET between deciduous and conifer stands may be smaller than that inferred solely from summer observations. This study provides a direct means to validate land surface processes in global climate models attempting to capture vegetation‐climate feedbacks in northern terrestrial regions