The main topics of the project under submission is how properties of arithmetic nature vary in families of varieties. The notion of family has to be understood either in its geometric classical meaning of a flat morphism of schemes or in its categorical one of algebraic stack. The researchers involved in the project under submission are working on special aspects of this fundamental question using approaches of different nature in the general frame of arithmetic geometry, such as deformation theory, general theory of stacks, rational points on moduli spaces (modular curves, Shimura varieties, Hurwitz spaces etc.), étale fundamental groups of schemes and stacks, l-adic representations, diophantine geometry etc., all of which are very active areas of investigation worldwide. Modern arithmetic geometry is often considered to be born in France, under the impulse of A. Grothendieck in the 60's, who elaborated, together with the French school, its fundations in the EGA and SGA. The theory of stacks, Galois categories, l-adic cohomology etc. were formalized during this period and have been developped since then, being fundamental theoretic tools to understand the objects of arithmetic geometry. Around the same period, diophantine geometry, which focusses on 'varieties', that is reduced schemes of finite type and separated over fields and stems from problem of more effective nature, started to develop powerful technical tools such as heights to investigate questions related to rational points on varieties. The theoretical tools of Grothendieck's formalism and the more technical ones of diophantine geometry are now intimately mixed and the conjugation of both has maintained the impressive development of modern arithmetic geometry for the past 50 years. The purpose of this project is to understand better some of the main problems at stake in the study of variation of arithmetic properties in families as well as the different approaches and technics that were developped to try and tackle them. Our basic strategy is to organize series of short workshops (averagely three days workshops, twice or three times a year) around common themes of interest. Half of the talks will be given by researchers involved in the project, as in a working group, whereas the other half will be given by specialists of the topics. Hopefully, this sharing of knowledges should bring new insights to the specific problems studied by each of the researchers and help develop collaborations between them. Due to its transversal dimension and its learning purposes, we hope that our research project will interact constructively with other more specialized projects in arithmetic or diophantine geometry.r

In the EVIDEN project, we are interested in an emerging area in Information Visualization which deals with the exploration and the visual analysis of dynamic data. Our objective is to devise methods and algorithms for the visualization and navigation of dynamic and relational data. Following the visualization "pipeline", research in the EVIDEN project focuses on four main topics: 1/ Definition of a data structure that is versatile, flexible and optimized enough to store large dynamic and relational data. This data structure must be able to guarantee efficient access and update times. 2/ The design of methods for the decomposition and extraction of regions of interest in dynamic data. Decomposition methods must, on one hand, group similar elements and, on the other limit changes during data evolution. Methods to extract regions of interest must allow the detection and the extraction of sub-networks with atypical behaviours. 3/ The design of efficient methods for the visualization of dynamic data: we focus on two main topics, the visual representation of the dynamic data and the visual representation of data evolution. 4/ The design of interaction methods for dynamic data: adapting and/or formally redefining interaction methods for static data as in previous work is required by data evolution and dynamism. The types of problems that the EVIDEN project is addressing emerge naturally in the application domains of bioinformatics and biology. Ultimately, it aims at contributing to the Health sciences. Other application domains could also benefit from these results.

Free radicals are nowadays of paramount importance in organic chemistry and many synthesis of complex natural products have been achieved recently by incorporating one or several steps involving such reactive species. Free-radical reactions using Bu3SnH or (Bu3Sn)2 respectively in reduction processes and formations of C-C bonds are the most useful tools in the armory of organic chemists and any radical chemistry practitioner will find very difficult to get away from Bu3Sn and other tin reagents to sustain a radical chain. Tin derivatives however suffer from several drawbacks including an acute toxicity and often, tedious purifications and contamination of final products. The Environmental Protection Agency (EPA) has recently restricted their use, prompting chemists to envision valuable alternatives for these compounds. In organic radical chemistry, although several elegant solutions have been proposed recently, efforts remain to be done to provide a simple, non toxic, easily available tributyltin surrogate. Silicon radicals possess attractive features which parallel those of tin radicals, and maybe viewed as non toxic candidates to replace tin, providing a valuable and environmentally benign solution to this long standing problem. Although limited in scope, some recent reports clearly establish that silyl radicals can promote radical chain reactions, which has prompted us to look more carefully in this direction. We propose in this project a tin-free methodology relying on the use of silyl radicals as initiators for a number of radical transformations, including powerful chain transfer processes. Our approach is based on intramolecular homolytic substitutions at silicon, namely aryl and silyl group migrations or homolytic ring closure, two processes which have been little exploited so far. The required silyl-centered radical would be generated from a carbon-centered radical through a 5- or a 6-exo cyclization process. The carbon radical would in turn be generated from a borane precursor, itself prepared in situ from readily available arylsilyl- or disilyl- alkenes. We thus plan, within this project, to design first silyl radical precursors, having both a boron moiety at one end of a carbon chain (as a source of carbon radical) and a silicon group at the other end of the chain, the required silyl radical being generated upon a cyclization process. These silyl radicals will then be used to initiate various chain transfer processes, allowing these reactions to be performed under tin-free conditions, extending further their range of application. Thus, this chemistry is not restricted to reduction of alkyl or aryl halides, the focus of most studies involving silicon radical chemistry so far, but is directed toward the more challenging and more useful C-C bond formation through chain transfer reactions.The utility of such silicon-centered radicals will finally be illustrated in the synthesis of biologically relevant substituted piperidinones, using a novel multi-component radical chain transfer strategy. Theoretical studies will be performed in parallel, including ab initio calculations of the cyclization reaction pathways and calculations of bond dissociation energies of disilane precursors. These investigations will provide useful informations for a more efficient rational design of the structure of silyl radical precursors. The project will involve partners, which expertise has been recognized in boron (P. Renaud, Berne) and silicon chemistry (Y. Landais, Bordeaux) as well as in theoretical chemistry (F. Castet, Bordeaux). We believe that this strategy should open new avenues in radical chemistry with clean processes free of toxic alkyltin residues.

Music information retrieval research area involves new methods for classification, indexation and retrieval of musical audio signals. One of the main open problems of this area is the estimation of music similarity between - musical pieces. This problem requires multidisciplinary expertise in various - fields such as musical theory, audio signal processing, algorithmic for data - structure comparison, etc. Existing music similarity systems essentially - consider timbre similarity. Our project team aims at investigating the adaptation of algorithms applied in bioinformatics or string recognition to - the musical context. Such algorithms compute a similarity score between two - sequences. First studies led to promising results. Nevertheless the - adaptation to musical audio data raises new problems in both algorithmic and - computer music fields. During this project, several methods that take into - account musical characteristics such as melody, harmony, rhythm, etc. will be - investigated and evaluated according to listening experiments and existing - symbolic and audio databases. Applications of such algorithms are numerous: query-y-humming, query-by-example, automatic summaries, evaluation of musical performances, etc. ...

The chemistry of the interstellar medium (ISM) has become an important area of research in recent years. Thanks to instrumental developments, many new molecules are discovered every year, increasing our knowledge of the complexity of the ISM. The physical conditions in such regions – characterized by very low temperature and density - are very different to what we experience on Earth. It has been necessary for experimental chemists to develop novel techniques to measure the reactivity of chemical species in ISM-like conditions. It is only recently however that astrochemists have begun to understand the importance of neutral-neutral reactions in the ISM, whose behaviour at low temperature remained largely unknown until recently. Nevertheless, astrochemical reaction networks include studied and unstudied neutral-neutral reactions alike, with the rate coefficients for the unstudied reactions being simply estimated in the model. Thus, the chemistry in these models, which is largely driven by not quantified reactions, is subsequently used by astronomers to simulate the chemistry of the ISM in star and planet forming regions. To draw any substantial conclusions from the comparison between the observations and the models, it is crucial to know the model limitations due to uncertainties in the reaction rate coefficients. In this proposal, we wish to bring together different but complementary fields: experimental chemists studying low temperature reactions and astronomers modelling interstellar chemistry. The astronomer of our project is working actively to improve chemical networks for the ISM. She has developed a number of numerical tools to estimate the uncertainties in theoretical species abundances due to rate coefficient imprecision to give a quantitative meaning to the model predictions. She has also developed methods to prioritize reactions that need to be studied by experimental chemists. The chemists of our project have been working for several years on the kinetics of neutral-neutral reactions at low temperature. This team is currently working on the creation of a unique and comprehensive chemical database for astrochemistry (the ISM and planetary atmospheres): KIDA (KInetic Database for Astrochemistry). Such a tool is required to optimize the efficiency of the collaboration between chemists and astrochemists. KIDA is constructed to be useful for astrophysicists and planetary scientists, and to make the chemists work visible to the entire community. This ANR proposal concerns the development of KIDA and the improvement of the data for nitrogen chemistry contained within. For the construction of KIDA, we ask for an assistant engineer who will be responsible for the development of the web interface and for feeding the database. The second part of this proposal concerns the construction of a new experiment to measure the reactivity of atoms with radicals. Although these processes present a challenge for experimentalists, they would be a significant advance for astrochemistry since such reactions are highly important in the ISM. With this new experiment, we would also be able to measure absolute branching ratios for the products of these reactions. Although N-bearing chemistry is typically used to probe the chemical processes that occur during the cold pre-stellar phases, reactions between N atoms and radicals have never been studied at low temperature. We will focus on the most important reactions of atomic nitrogen, identified by the numerical tools previously described. In order to utilize all the information obtained by the experimentalists, we will improve the numerical tools developed to simulate the interstellar chemistry and in particular the treatment of branching ratios uncertainties. Using the new experimental results and new astrochemical models, we will make a detailed analysis of the impact of the measured rate coefficients on the chemistry in star forming regions. Considering the sensitivity of present models to the selected reactions, we expect significant changes in the predictions for nitrogen chemistry in the ISM. The final goal of the project is to improve the predictions of chemical models for the different stages of star and planet formation and be ready for the most powerful observing instruments in this field: the Herschel Space Observatory (HSO) and the Atacama Large Millimeter Array (ALMA).