Modernités multiples et critique social des technologies en Europe et Amérique Latine

Aujourd’hui encore, les liens entre les idéologies du progrès et les développements technologiques restent souvent très forts et non remis en cause. Toutefois, au même moment, nous observons également une critique sociale de plus en plus virulente des conséquences liées à ces développements. Cet article, écrit par quatre chercheurs d’Europe et d’Amérique latine, traite de la manière dont sont appréhendées et critiquées les problématiques liées à la science et la technologie en Europe, dans le cadre des offices de « Technology Assessment ». En s’appuyant sur une connaissance poussée des pratiques européennes, les auteurs considèrent que même si les pratiques de Technology Assessment se sont avérées efficaces dans le contexte européen, leur diversité indique qu’un tel outil ne pourrait être transféré comme tel dans un autre contexte politique, culturel et institutionnel, extérieur à l’Europe. S’appuyant sur le concept de modernités multiples, ils étendent leurs réflexions à l’Amérique latine, où des avancées significatives existent dans les régimes de science et d’innovation. Leurs conclusions soulignent l’importance de construire une capacité de Technology Assessment adaptée aux besoins locaux, à travers un processus itératif de co-construction entre les praticiens et de nombreux stakeholders, en ce compris les citoyens.Fil: Delvenne, Pierre. Université de Liège; BélgicaFil: Erpicum, Martin. CRP Henri Tudor; LuxemburgoFil: Hupet, Pierre. Red Alma Mater; ColombiaFil: Vasen, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes; Argentin

Estimation of root water uptake parameters by inverse modeling with soil water content data

In this paper we have tested the feasibility of the inverse modeling approach to derive root water uptake parameters (RWUP) from soil water content data using numerical experiments for three differently textured soils and for an optimal drying period. The RWUP of interest are the rooting depth and the bottom root length density. In a first step, a thorough sensitivity analysis was performed. This showed that soil water content dynamics is relatively insensitive to RWUP and that the sensitivity depends on the texture of the considered soil. For medium-fine textured soil, the sensitivity is particularly low due to relatively high unsaturated hydraulic conductivity values. These ones allow a “compensating effect” to occur, i.e., vertical unsaturated water fluxes overshadowing in some way the root water uptake. In a second step, we analyzed the well-posedness of the solution (stability and nonuniqueness) when only RWUP are optimized. For this case, the inverse problem is clearly ill-posed except for the estimation of the rooting depth parameter for coarse and the very fine textured soils. In a third step, we addressed the case where RWUP are estimated simultaneously with additional parameters of the system (i.e., with soil hydraulic parameters). For this case, our study showed that the inverse problem is well-posed for the coarse and very fine textured soils, allowing for the estimation of both RWUP of interest provided that a powerful global optimization algorithm is used. On the contrary, the estimation of RWUP is unfeasible for medium-fine textured soil due to the “compensating effect” of the vertical unsaturated water flows. In conclusion, we can state that the inverse modeling approach can be applied to derive RWUP for some soils (coarse and very fine textured) and that the feasibility is strongly improved if the RWUP are simultaneously optimized with additional parameters. Nevertheless, more detailed research is needed to apply the inverse modeling approach to real cases for which additional issues are likely to be encountered such as soil heterogeneity and root dynamics

Estimating spatial mean root-zone soil moisture from point-scale observations

Root zone soil moisture is a key variable in many land surface hydrology models. Often, however, there is a mismatch in the spatial scales at which models simulate soil moisture and at which soil moisture is observed. This complicates model validation. The increased availability of detailed datasets on space-time variability of root-zone soil moisture allows for a posteriori analysis of the uncertainties in the relation between point-scale observations and the spatial mean. In this paper we analyze three comprehensive datasets from three different regions. We identify different strategies to select observation sites. For instance, sites can be located randomly or according to the rank stability concept. For each strategy, we present methods to quantify the uncertainty that is associated with this strategy. In general there is a large correspondence between the different datasets with respect to the relative uncertainties for the different strategies. For all datasets, the uncertainty can be strongly reduced if some information is available that relates soil moisture content at that site to the spatial mean. However this works best if the space-time dynamics of the soil moisture field are known. Selection of the site closest to the spatial mean on a single random date only leads to minor reduction of the uncertainty with respect to the spatial mean over seasonal timescales. Since soil moisture variability is the result of a complex interaction between soil, vegetation, and landscape characteristics, the soil moisture field will be correlated with some of these characteristics. Using available information, we show that the correlation with leaf area index or a wetness coefficient alone is insufficient to predict if a site is representative for the spatial mean soil moisture content

Multiscale entropy-based analyses of soil transect data

A deeper understanding of the spatial variability of soil properties and the relationships between them is needed to scale up measured soil properties and to model soil processes. The object of this study was to describe the spatial scaling properties of a set of soil physical properties measured on a common 1024-m transect across arable fields at Silsoe in Bedfordshire, east-central England. Properties studied were volumetric water content ({theta}), total porosity ({pi}), pH, and N2O flux. We applied entropy as a means of quantifying the scaling behavior of each transect. Finally, we examined the spatial intrascaling behavior of the correlations between {theta} and the other soil variables. Relative entropies and increments in relative entropy calculated for {theta}, {pi}, and pH showed maximum structure at the 128-m scale, while N2O flux presented a more complex scale dependency at large and small scales. The intrascale-dependent correlation between {theta} and {pi} was negative at small scales up to 8 m. The rest of the intrascale-dependent correlation functions between {theta} with N2O fluxes and pH were in agreement with previous studies. These techniques allow research on scale effects localized in scale and provide the information that is complementary to the information about scale dependencies found across a range of scale

Evaluation des besoins et des activités. Problématique de leur localisation. Critères, méthodes et applications pour la révision des plans de secteur. Problématique pour la mise en oeuvre des zones d'aménagement différé

Rapport final de la subvention 2001, Cinquième Volum

The influence of conceptual (mis)match on collaborative referring in dialogue

When two dialogue partners need to refer to something, they jointly negotiate which referring expression should be used. If needed, the chosen referring expression is then reused throughout the interaction, which potentially has a direct, positive impact on subsequent communication. The purpose of this study was to determine if the way in which the partners view, or conceptualise, the referent under discussion, affects referring expression negotiation and subsequent communication. A matching task was preceded by an individual task during which participants were required to describe their conceptualisations of abstract tangram pictures. The results revealed that participants found it more difficult to converge on single referring expression during the matching task when they initially held different conceptualisations of the pictures. This had a negative impact on the remainder of the task. These findings are discussed in light of the shared versus mutual knowledge distinction, highlighting how the former directly contributes to the formation of the latter