Urban Transport in France : Moving to a Sustainable Policy

The organisation of urban public transport in France has some specificity in comparison to other European countries, even if problems are similar and the creation of the European Union leads progressively to an harmonisation. To understand these differences, it is first necessary to focus on historical and institutional aspects, including the 1982 Transport Law. This paper describes the evolution of the urban transport policy, giving illustration through the case of Lyon's conurbation; it highlights the reason for an unsuccessful attempt to reduce car use for urban trips, and discusses the main stakes for implementing new sustainable transport policies in French cities.Institutional Aspect ; Public Transport ; Sustainable Transport Policy ; Transport Law ; Urban Transport Policy ; Lyon (France)

Hexagonal eutectic solidification patterns operating near a marginal stability point

We study the long-time dynamics of hexagonal directional-solidification patterns in bulk samples of a transparent eutectic alloy using an optical method which permits real-time observation of the growth front. A slow dilatation of the patterns due to a slight curvature of the isotherms drives the system into a permanent regime, close to the threshold for the rod splitting instability. Thus an apparently minor instrumental imperfection suffices to maintain the system near a marginal stability point. This answers the long-standing question of spacing selection in bulk eutectic growth

Stated adaptation surveys and choice process: Some methodological issues

The “Stated Adaptation” survey is an interactive technique which allows us to obtain a clearer picture of the attitudes and behaviours of individuals when confronted with hypothetical situations, in particular inexperienced travel conditions. This method makes use of a simulation game whose purpose is to explore on small samples individuals' choice processes when selecting between the different transport alternatives which are available to them. This paper describes how gaming-simulation is designed, with reference to the issues tackled by two surveys which have recently been carried out in France (reactions to urban road pricing and perception of electric vehicles). It describes the benefits of this experimental approach which allows stated behaviours to be checked to a considerable degree. The limits and potential developments of this survey technique are also discussed.choice process ; stated response ; survey method ; travel behaviour

Food availability and competition do not modulate the costs of Plasmodium infection in dominant male canaries

Understanding the different factors that may influence parasite virulence is of fundamental interest to ecologists and evolutionary biologists. It has recently been demonstrated that parasite virulence may occur partly through manipulation of host competitive ability. Differences in competitive ability associated with the social status (dominant or subordinate) of a host may determine the extent of this competition-mediated parasite virulence. We proposed that differences between subordinate and dominant birds in the physiological costs of infection may change depending on the level of competition in social groups. We observed flocks of domestic canaries to determine dominant or subordinate birds, and modified competition by providing restricted (high competition) or ad libitum food (low competition). Entire flocks were then infected with either the avian malaria parasite, Plasmodium relictum or a control. Contrary to our predictions we found that the level of competition had no effect on the outcome of infection for dominant or subordinate birds. We found that dominant birds appeared to suffer greater infection mediated morbidity in both dietary treatments, with a higher and more sustained reduction in haematocrit, and higher parasitaemia, than subordinates. Our results show that dominance status in birds can certainly alter parasite virulence, though the links between food availability, competition, nutrition and virulence are likely to be complex and multifaceted

Autoroutes, activités et territoires: propositions méthodologiques pour évaluer l'impact de l'autoroute sur la spatialisation des activités

International audienceL'autoroute est-elle capable de fixer les activités ? Cette question relativement simple, ancienne etcontroversée, posée par la Société des Autoroutes Paris-Rhin-Rhône n'a toujours pas été résolue malgrél'acceptation d'une logique d'interactions primant sur une logique d'effets automatiques d'un seul élément. Ellese heurte essentiellement à un blocage méthodologique qui empêche, en l'état actuel des recherches, d'yrépondre de manière plus rigoureuse et d'exporter des conclusions validées dans tous les cas. Aussi, nousproposons une nouvelle méthode de recherche qui intègre la totalité du système de localisation des activités etune nouvelle conception de recherche qui n'essaye plus d'isoler le facteur autoroutier mais tente d'analyser lerôle joué par l'autoroute au sein du système auquel elle appartient. L'aboutissement de nos recherches sematérialise par la réalisation d'une grille d'analyse résolument systémique visant à comprendre et expliquer lesinteractions entre autoroutes et système de localisation des activités, l'un de ses développements potentielspouvant résider dans une formalisation de type système expert

Assessment of the potential impacts of plant traits across environments by combining global sensitivity analysis and dynamic modeling in wheat

A crop can be viewed as a complex system with outputs (e.g. yield) that are affected by inputs of genetic, physiology, pedo-climatic and management information. Application of numerical methods for model exploration assist in evaluating the major most influential inputs, providing the simulation model is a credible description of the biological system. A sensitivity analysis was used to assess the simulated impact on yield of a suite of traits involved in major processes of crop growth and development, and to evaluate how the simulated value of such traits varies across environments and in relation to other traits (which can be interpreted as a virtual change in genetic background). The study focused on wheat in Australia, with an emphasis on adaptation to low rainfall conditions. A large set of traits (90) was evaluated in a wide target population of environments (4 sites x 125 years), management practices (3 sowing dates x 2 N fertilization) and $CO_2$ (2 levels). The Morris sensitivity analysis method was used to sample the parameter space and reduce computational requirements, while maintaining a realistic representation of the targeted trait x environment x management landscape ($\sim$ 82 million individual simulations in total). The patterns of parameter x environment x management interactions were investigated for the most influential parameters, considering a potential genetic range of +/- 20% compared to a reference. Main (i.e. linear) and interaction (i.e. non-linear and interaction) sensitivity indices calculated for most of APSIM-Wheat parameters allowed the identifcation of 42 parameters substantially impacting yield in most target environments. Among these, a subset of parameters related to phenology, resource acquisition, resource use efficiency and biomass allocation were identified as potential candidates for crop (and model) improvement.Comment: 22 pages, 8 figures. This work has been submitted to PLoS On