Bursting of rigid bubbles

We propose here a fluid dynamics video relating the bursting of soap rigid films.Comment: 4 pages and 2 videos included for the Gallery of Fluid Motion 201

AMD-stability in presence of first order Mean Motion Resonances

The AMD-stability criterion allows to discriminate between a-priori stable planetary systems and systems for which the stability is not granted and needs further investigations. AMD-stability is based on the conservation of the Angular Momentum Deficit (AMD) in the averaged system at all orders of averaging. While the AMD criterion is rigorous, the conservation of the AMD is only granted in absence of mean-motion resonances (MMR). Here we extend the AMD-stability criterion to take into account mean-motion resonances, and more specifically the overlap of first order MMR. If the MMR islands overlap, the system will experience generalized chaos leading to instability. The Hamiltonian of two massive planets on coplanar quasi-circular orbits can be reduced to an integrable one degree of freedom problem for period ratios close to a first order MMR. We use the reduced Hamiltonian to derive a new overlap criterion for first order MMR. This stability criterion unifies the previous criteria proposed in the literature and admits the criteria obtained for initially circular and eccentric orbits as limit cases. We then improve the definition of AMD-stability to take into account the short term chaos generated by MMR overlap. We analyze the outcome of this improved definition of AMD-stability on selected multi-planet systems from the Extrasolar Planets Encyclopeadia.Comment: Accepted by A and A 07/10/1

WHO OWNS THE WATER? A CASE STUDY OF EL PASO DEL NORTE

This paper, first, reviews the report filed by the Western Water Policy Review Advisory Commission since it touches on all the major issues associated with water rights and uses in the Upper Rio Grande Basin, defined as that part of the river from the San Luis Valley in Colorado to Fort Quitman, Texas. Second, the paper reviews historical developments over water use and water rights and briefly discusses the major characteristics of El Paso del Norte that do and will have an impact on water supply and consumption. Then the paper reviews the positions of the major stakeholders in the Basin, paying particular attention to their legal arguments. Finally, the paper attempts to describe the possible alternative outcomes of the continuing struggle over water.Water rights--Rio Grande Valley, Water supply--Management --Texas--Lower Rio Grande Valley, Water supply--Management--Mexico--Rio Grande Valley, Resource /Energy Economics and Policy,

Reduction of the COSMOS Southern Sky galaxy survey data to the RC3 standard system

After having cross-identified a subsample of LEDA galaxies in the COSMOS database, we defined the best relations to convert COSMOS parameters (coordinates, position angle, diameter, axis ratio and apparent magnitude) into RC3 system used in the LEDA database. Tiny secondary effects can be tested: distance to plate cenetrs effect and air-mass effect. The converted COSMOS parameters are used to add missing parameters on LEDA galaxies. Key words: galaxies - catalogue - photometryComment: 5 pages, postcript including figures, to appear in MNRAS, reprint requests: [email protected]

Expectations for the Deep Impact collision from cometary nuclei modelling

Using the cometary nucleus model developed by Espinasse et al. (1991), we calculate the thermodynamical evolution of Comet 9P/Tempel 1 over a period of 360 years. Starting from an initially amorphous cometary nucleus which incorporates an icy mixture of H2O and CO, we show that, at the time of Deep Impact collision, the crater is expected to form at depths where ice is in its crystalline form. Hence, the subsurface exposed to space should not be primordial. We also attempt an order-of-magnitude estimate of the heating and material ablation effects on the crater activity caused by the 370 Kg projectile released by the DI spacecraft. We thus show that heating effects play no role in the evolution of crater activity. We calculate that the CO production rate from the impacted region should be about 300-400 times higher from the crater resulting from the impact with a 35 m ablation than over the unperturbed nucleus in the immediate post-impact period. We also show that the H2O production rate is decreased by several orders of magnitude at the crater base just after ablation