How to test SME with space missions ?

In this communication, we focus on possibilities to constrain SME coefficients using Cassini and Messenger data. We present simulations of radioscience observables within the framework of the SME, identify the linear combinations of SME coefficients the observations depend on and determine the sensitivity of these measurements to the SME coefficients. We show that these datasets are very powerful for constraining SME coefficients.Comment: Presented at the Sixth Meeting on CPT and Lorentz Symmetry, Bloomington, Indiana, June 17-21, 2013. 4 pages, 1 figur

Developement dynamics of organic farming : elements for debate

Synthetic overview of the third workshop : development dynamics of organic farming

Agroecology: Polysemy, Pluralism And Controversies

In recent years, a growing number of actors and institutions, in different countries, have begun using the notion of Agroecology, which has led to an expansion of its polysemy and its controversies. Taking this into account, this paper analyzes, based on the Brazilian and French experiences, the peculiarities of Agroecology in four different fields: science, social movements, government policies, and education. It also discusses three other issues: the analytical, programmatic and normative discourses; the different definitions, in the fields of science and education, of the object of study of Agroecology; and the different formulations regarding its fundamental principles. It is argued that, in this new context, recognition of this pluralism and the controversies acquires a central role in the construction of knowledge in the various fields linked to Agroecology.19312

Testing Gravitation in the Solar System with Radio Science experiments

The laws of gravitation have been tested for a long time with steadily improving precision, leading at some moment of time to paradigmatic evolutions. Pursuing this continual effort is of great importance for science. In this communication, we focus on Solar System tests of gravity and more precisely on possible tests that can be performed with radio science observations (Range and Doppler). After briefly reviewing the current tests of gravitation at Solar System scales, we give motivations to continue such experiments. In order to obtain signature and estimate the amplitude of anomalous signals that could show up in radio science observables because of modified gravitational laws, we developed a new software that simulates Range/Doppler signals. We present this new tool that simulates radio science observables directly from the space-time metric. We apply this tool to the Cassini mission during its cruise from Jupiter to Saturn and derive constraints on the parameters entering alternative theories of gravity beyond the standard Parametrized Post Newtonian theory.Comment: proceedings of SF2A 2011 - minor changes (typos corrected - references updated

Analysis of transition forms towards more ecologically-oriented farming: the case of organic farming and integrated crop protection

Interdisciplinary approaches developed concerning the conversion to organic farming show that the types of conversion trajectories can be differentiated on the basis of the progression of crop protection changes within a larger framework where relationships to other “objects” are transformed – the soil, products, rotations, work organisation, marketing, social networks and knowledge acquisition. In the case of integrated plant production, the extent of changes depends on the degree of recomposition of agronomic practices. This transition implies major knowledge acquisition that relies on the support and contribution of advisors and on the group dynamics that develop within a group of farmers. Transitions towards integrated crop protection are, by their nature, more reversible and therefore more fragile than the conversion to organic farming. This is due to the fact that they are not stabilised by a certification or by the market, and analysis shows that their sustainability is linked in part to their integration within a group dynamics

Alternative Food Networks And New Producer-consumer Relations In France And In Brazil

This paper presents an analysis about agroecological alternative food networks and new producer-consumer relationships in France and Brazil. The investigation method is based on descriptive and qualitative research about 20 cases (qualitative interviews), selected with stakeholders (farmers, traders, consumers and food experts) in France and Southern Brazil. A typology about the characteristics and organization to short circuits trade is provided. The results show that alternative food networks are very diverse and dynamic, being a social, economic and environmental option to family farming, strengthening local markets and reconnecting producers and consumers. In these countries, the successful initiatives of alternative networks occur in places where there is coordination between food networks stakholders such as the government, NGOs, private enterprises, farmers and consumers' organizations.19212

Ultimate decoherence border for matter-wave interferometry

Stochastic backgrounds of gravitational waves are intrinsic fluctuations of spacetime which lead to an unavoidable decoherence mechanism. This mechanism manifests itself as a degradation of the contrast of quantum interferences. It defines an ultimate decoherence border for matter-wave interferometry using larger and larger molecules. We give a quantitative characterization of this border in terms of figures involving the gravitational environment as well as the sensitivity of the interferometer to gravitational waves. The known level of gravitational noise determines the maximal size of the molecular probe for which interferences may remain observable. We discuss the relevance of this result in the context of ongoing progresses towards more and more sensitive matter-wave interferometry.Comment: 4 page