Publications

Diffusion and Reaction-Diffusion in Steady Flows at Large Peclet Numbers - Pomeau, Y.
in TRANSPORT AND MIXING IN GEOPHYSICAL FLOWS edited by Weiss, JB and Provenzale, A (2008), 

Abstract : In many, if not most; geophysical flows molecular diffusion is formally negligible because its relative importance is measured by the inverse of a large Peclet number. This has motivated a number of studies, based in some way or another on various theoretical approaches to turbulence, where the assumed randomness of the turbulent flow plays the center role. If one adds to this complicated situation of the passive scalar the possibility of chemical reactions changing the chemical layout of the fluid; the number of unresolved issues increases dramatically. The chemistry is often such that, without flow, the reaction progresses by a front (the flame front in gaseous combustion) sweeping the system, across which the reaction takes place, from an unburnt (fresh) side to a burnt side. I look at these problems in the case of steady flows made of rolls; as generated by Rayleigh-Benard instability for instance, certainly an idealization of real turbulence, although it is not; clear by how much. The propagation of the chemical reaction in this system depends first on the diffusion of a passive scalar, an interesting question in the limit of a large Peclet number in a flow without open flow lines. The main result there is that the effective diffusion is somewhere in between the molecular diffusion and the ``turbulent'' diffusion. Once chemical reactions are taken into account, that is when one considers the reaction-diffusion case, one finds that the front speed is the laminar propagation velocity (without flow) times the Peclet number to the power 1/4. I refine this last result and give the behavior of the prefactor in the Zel'dovich limit of a narrow reaction zone.

Syndication Strategies in Venture Capital Networks - Mas, David and Vignes, Annick and Weisbuch, Gerard
in STRATEGY AND GOVERNANCE OF NETWORKS: COOPERATIVES, FRANCHISING, AND STRATEGIC ALLIANCES edited by Hendrikse, G (2008), 

Abstract : Empirical evidence shows that venture capitalists syndicate to finance start-ups. This paper focuses on the role of the social network generated by these syndication operations. We consider the links developed between venture capitalists, through co-investment rounds, and we study their relationships both through network and econometric analyses. We first demonstrate that the syndication network is not random. Secondly, we show that the different assortativities (degree, spatial, industrial) are positive, suggesting that venture capitalists tend to co-invest with their peers. Thirdly, we measure the influence of different proximities (spatial, national and industrial) on the collaborations between the different players. National and industrial proximity have a strong impact on the determination of links. Finally, we provide evidence that past partners are preferred for future syndication, even if new links do appear regularly.

The science and craft of autostereograms - Ninio, Jacques
SPATIAL VISION 21, 185-200 (2008)

Symmetry influences colour perception: the transparent sheet model - Ninio, J.
PERCEPTION 37, 147 (2008)

Depth perception following monocular fusion of two images with a squinting eye - Rychkova, S. I. and Ninio, J.
PERCEPTION 37, 15-16 (2008)

Dedication to Pierre Lallemand on the occasion of his retirement - d'Humieres, Dominique and Krafczyk, Manfred and Luo, Li-Shi and Rubinstein, Robert
INTERNATIONAL JOURNAL OF COMPUTATIONAL FLUID DYNAMICS 22, 437-439 (2008)

Laser Doppler measurement of inertial particle and bubble accelerations in turbulence - Volk, R. and Mordant, N. and Verhille, G. and Pinton, J. -F.
EPL 81,  (2008)

Generic behaviours in impact fragmentation - Sator, N. and Mechkov, S. and Sausset, F.
EPL 81,  (2008)

Spontaneous generation of spiral waves by a hydrodynamic instability - Habibi, M. and Moller, P. C. F. and Ribe, N. M. and Bonn, D.
EPL 81,  (2008)

Reconstructing a random potential from its random walks - Cocco, S. and Monasson, R.
EPL 81,  (2008)

Experimental evidence of non-Amontons behaviour at a multi-contact interface - Scheibert, J. and Prevost, A. and Frelat, J. and Rey, P. and Debregeas, G.
EPL 83,  (2008)

The spectrum of the fractional Laplacian and First-Passage-Time statistics - Katzav, E. and Adda-Bedia, M.
EPL 83,  (2008)

Some applications of magnetic resonance imaging in fluid mechanics: Complex flows and complex fluids - Bonn, Daniel and Rodts, Stephane and Groenink, Maarten and Rafai, Salima and Shahidzadeh-Bonn, Noushine and Coussot, Philippe
ANNUAL REVIEW OF FLUID MECHANICS 40, 209-233 (2008)

A caged retinoic acid for one- and two-photon excitation in zebrafish embryos - Neveu, Pierre and Aujard, Isabelle and Benbrahim, Chouaha and Le Saux, Thomas and Allemand, Jean-Francois and Vriz, Sophie and Bensimon, David and Jullien, Ludovic
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 47, 3744-3746 (2008)

Physics - The force of fluctuations - Balibar, Sebastien
NATURE 451, 136-137 (2008)

Shear thickening of cornstarch suspensions as a reentrant jamming transition - Fall, Abdoulaye and Huang, N. and Bertrand, F. and Ovarlez, G. and Bonn, Daniel
PHYSICAL REVIEW LETTERS 100,  (2008)

The spectrum of large powers of the Laplacian in bounded domains - Katzav, E. and Adda-Bedia, M.
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL 41,  (2008)

Current noise through a kondo quantum dot in a SU(N) fermi liquid state - Mora, Christophe and Leyronas, Xavier and Regnault, Nicolas
PHYSICAL REVIEW LETTERS 100,  (2008)

The traveling-wave approach to asexual evolution: Muller's ratchet and speed of adaptation - Rouzine, Igor M. and Brunet, Eric and Wilke, Claus O.
THEORETICAL POPULATION BIOLOGY 73, 24-46 (2008)

Analyzing single-bond experiments: Influence of the shape of the energy landscape and universal law between the width, depth, and force spectrum of the bond - Husson, Julien and Pincet, Frederic
PHYSICAL REVIEW E 77,  (2008)