This article analyzes how the notion of “sovereignty” has been and is still mobilized in the realm of the digital. This notion is increasingly used to describe various forms of independence, control, and autonomy over digital infrastructures, technologies, and data. Our analysis originates from our previous and current research with activist “tech collectives” where we observed a use of the notion to emphasize alternative technological practices in a way that significantly differs from a governmental policy perspective. In this article, we review several publications in order to show the difference, if not diverging ways in which the notion is being conceptualized, in particular by different groups. We show that while the notion is generally used to assert some form of collective control on digital content and/or infrastructures, the precise interpretations, subjects, meanings, and definitions of sovereignty can significantly differ.

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This article explores the notion of digital non-participation as a form of mediated political action rather than as mere passivity. We generally conceive of participation in a positive sense, as a means for empowerment and a condition for democracy. However, participation is not the only way to achieve political goals in the digital sphere and can be hampered by the 'dark sides' of participatory media, such as surveillance or disempowering forms of interaction. In fact, practices aimed at abandoning or blocking participatory platforms can be seen as politically significant and relevant. We propose here to conceptualize these activities by developing a framework that includes both participation and non-participation. Focusing on the political dimensions of digital practices, we draw four categories: active participation, passive participation, active non-participation, and passive non-participation. This is not intended as a conclusive classification, but rather as a conceptual tool to understand the relational nature of participation and non-participation through digital media. The evolution of the technologies and practices that compose the digital sphere forces us to reconsider the concept of political participation itself.

Couture, Sté phane, Denis Massicotte, Carole Lavoie, Claude Hillaire-Marcel, and Franç ois Pé ronnet. Oral [ 13 C]glucose and endogenous energy substrate oxidation during prolonged treadmill running. J Appl Physiol 92: 1255-1260, 2002. First published November 16, 2001 10.1152/japplphysiol.00437.2001.-Six male subjects were studied during running exercise (120 min, 69% maximal oxygen consumption) with ingestion of a placebo or 3.5 g/kg of [ 13 C]glucose (ϳ2 g/min). Indirect respiratory calorimetry corrected for urea excretion in urine and sweat, production of 13 CO2 at the mouth, and changes in plasma glucose 13 C/ 12 C were used to compute energy substrate oxidation. The oxidation rate of exogenous glucose increased from 1.02 at minute 60 to 1.22 g/min at minute 120 providing ϳ24 and 33% of the energy yield (%En). Glucose ingestion did not modify protein oxidation, which provided ϳ4-5%En, but significantly increased glucose oxidation by ϳ7%, reduced lipid oxidation by ϳ16%, and markedly reduced endogenous glucose oxidation (1.25 vs. 2.21 g/min between minutes 80 and 120, respectively). The oxidation rate of glucose released from the liver (0.38 and 0.47 g/min, or 10-13%En at minutes 60 and 120, respectively), and of plasma glucose (1.30-1.69 g/min, or 34 and 45%En and 50 and 75% of glucose oxidation) significantly increased from minutes 60 to 120, whereas the oxidation of muscle glycogen significantly decreased (1.28 to 0.58 g of glucose/min, or 34 and 16%En and 50 and 25% of glucose oxidation). These results indicate that, during moderate prolonged running exercise, ingestion of a very large amount of glucose significantly reduces endogenous glucose oxidation, thus sparing muscle and/or liver glycogen stores. exogenous glucose; stable isotopes; liver glucose production; muscle glycogen utilization; insulin; blood glucose THERE APPEARS TO BE NO detailed description of energy substrate fluxes, and particularly of plasma glucose kinetics, during prolonged running, except for the study by Hall et al. (11), which has only been presented as a preliminary report. Similarly, most of the studies concerning exogenous carbohydrate oxidation during exercise have been conducted on cycle ergometer. In these studies, the oxidation rate of exogenous carbohydrates has been shown to increase with workload (19,27,29) and with the amount ingested (1, 14, 36). At high absolute and relative workloads and for large amounts of carbohydrates ingested, the oxidation rate of exogenous glucose plateaus around 1.0 g/min, providing ϳ25% of the energy yield (13,14,26,36). When running exercise was used, the workload was low [40% maximal oxygen consumption (V O 2 max )] (22) or the amount of glucose ingested was small (0.4-0.8 g/min) (27, 28). Accordingly, the oxidation rate of exogenous glucose remained in the lower range of values reported (0.3-0.7 g/min). In the study by Derman et al. (10), exogenous glucose oxidation was compared in response to running and cycling exercise at a high workload (3.6 l O 2 /min; 80% V O 2 max ) with ingesti...

This paper deals with the problems of estimating irrigation water demand. We propose an original method of estimation in two steps. First, we develop a dynamic programming model in order to explain the optimal irrigation management plan. Based on a microeconomic approach describing the farmer's behavior, this economic model, introducing an agronomic model, and an algorithm of solution search, is used to compute a realistic database. Second, these data are used to estimate profit functions by a non-parametric method. The irrigation water demand function is estimated using a non-parametric derivation procedure.An application to irrigation water demand is proposed in the southwestern area of France where conflicts appear frequently. The same results appear for different climates: for small quantities of water available, irrigation water demand seems to be quite inelastic. If one increases the total quantity of water available, the shape of the curve changes and the demand appears more elastic. The threshold price at which the changes in price-responsiveness appears, depends on weather conditions and range from 0.30 F/m 3 in a wet year to 1.60 F/m 3 in a dry year. These results are crucial information for the regulator in order to analyze the effects of a water regulation policy, based on prices. The impact of an increase in the water price will depend not only on the climate but also on the location of the initial and final prices on the demand function.