2,061 research outputs found

    Secular models and Kozai resonance for planets in coorbital non-coplanar motion

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    In this work, we construct and test an analytical and a semianalytical secular models for two planets locked in a coorbital non-coplanar motion, comparing some results with the case of restricted three body problem. The analytical average model replicates the numerical N-body integrations, even for moderate eccentricities (\lesssim 0.3) and inclinations (10\lesssim10^\circ), except for the regions corresponding to quasi-satellite and Lidov-Kozai configurations. Furthermore, this model is also useful in the restricted three body problem, assuming very low mass ratio between the planets. We also describe a four-degree-of-freedom semianalytical model valid for any type of coorbital configuration in a wide range of eccentricities and inclinations. {Using a N-body integrator, we have found that the phase space of the General Three Body Problem is different to the restricted case for inclined systems, and establish the location of the Lidov-Kozai equilibrium configurations depending on mass ratio. We study the stability of periodic orbits in the inclined systems, and find that apart from the robust configurations L4L_4, AL4AL_4, and QSQS is possible to harbour two Earth-like planets in orbits previously identified as unstable UU and also in Euler L3L_3 configurations, with bounded chaos.Comment: 15 pages. 20 figure

    Algebra of chiral currents on the physical surface

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    Using a particular structure for the Lagrangian action in a one-dimensional Thirring model and performing the Dirac's procedure, we are able to obtain the algebra for chiral currents which is entirely defied on the constraint surface in the corresponding hamiltonian description of the theory.Comment: 10 page

    MAMA: An Algebraic Map for the Secular Dynamics of Planetesimals in Tight Binary Systems

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    We present an algebraic map (MAMA) for the dynamical and collisional evolution of a planetesimal swarm orbiting the main star of a tight binary system (TBS). The orbital evolution of each planetesimal is dictated by the secular perturbations of the secondary star and gas drag due to interactions with a protoplanetary disk. The gas disk is assumed eccentric with a constant precession rate. Gravitational interactions between the planetesimals are ignored. All bodies are assumed coplanar. A comparison with full N-body simulations shows that the map is of the order of 100 times faster, while preserving all the main characteristics of the full system. In a second part of the work, we apply MAMA to the \gamma-Cephei, searching for friendly scenarios that may explain the formation of the giant planet detected in this system. For low-mass protoplanetary disks, we find that a low-eccentricity static disk aligned with the binary yields impact velocities between planetesimals below the disruption threshold. All other scenarios appear hostile to planetary formation

    Non-covalent interactions at electrochemical interfaces : one model fits all?

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    Acknowledgements Funding from the DGI (Spanish Ministry of Education and Science) through Project CTQ2009-07017 is gratefully acknowledged. E.P.M.L. wishes to thank the Universidad Nacional de Co´rdoba, Argentina, for a grant within the ‘‘Programa de Movilidad Internacional de Profesores Cuarto Centenario’’.Peer reviewedPublisher PD

    2D-Drop model applied to the calculation of step formation energies on a (111) substrate

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    A model is presented for obtaining the step formation energy for metallic islands on (111) surfaces from Monte Carlo simulations. This model is applied to homo (Cu/Cu(111), Ag/Ag(111)) and heteroepitaxy (Ag/Pt(111)) systems. The embedded atom method is used to represent the interaction between the particles of the system, but any other type of potential could be used as well. The formulation can also be employed to consider the case of other single crystal surfaces, since the higher barriers for atom motion on other surfaces are not a hindrance for the simulation scheme proposed.Comment: 12 pages, LaTeX2e, 2 included EPS figures, submitted to Surface Science Subj-clas

    Optimising Humanness: Designing the best human-like Bot for Unreal Tournament 2004

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    This paper presents multiple hybridizations of the two best bots on the BotPrize 2014 competition, which sought for the best humanlike bot playing the First Person Shooter game Unreal Tournament 2004. To this aim the participants were evaluated using a Turing test in the game. The work considers MirrorBot (the winner) and NizorBot (the second) codes and combines them in two different approaches, aiming to obtain a bot able to show the best behaviour overall. There is also an evolutionary version on MirrorBot, which has been optimized by means of a Genetic Algorithm. The new and the original bots have been tested in a new, open, and public Turing test whose results show that the evolutionary version of MirrorBot apparently improves the original bot, and also that one of the novel approaches gets a good humanness level.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
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