RESUMO
The phase-space volume of regions of regular or trapped motion, for bounded or scattering systems with 2 degrees of freedom, respectively, displays universal properties. In particular, drastic reductions in the volume (gaps) are observed at specific values of a control parameter. Using the stability resonances we show that they, and not the mean-motion resonances, account for the position of these gaps. For more degrees of freedom, exciting these resonances divides the regions of trapped motion. For planetary rings, we demonstrate that this mechanism yields rings with multiple components.
RESUMO
As the theory of chaotic scattering in high-dimensional systems is poorly developed, it is very difficult to determine initial conditions for which interesting scattering events, such as long delay times, occur. We propose to use symmetry breaking as a way to gain the insight necessary to determine low-dimensional subspaces of initial conditions in which we can find such events easily. We study numerically the planar scattering off a disk moving on an elliptic Kepler orbit, as a simplified model of the elliptic restricted three-body problem. When the motion of the disk is circular, the system has an integral of motion, the Jacobi integral, which is no longer conserved for nonvanishing eccentricity. In the latter case, the system has an effective five-dimensional phase space and is therefore not amenable for study with the usual methods. Using the symmetric problem as a starting point we define an appropriate two-dimensional subspace of initial conditions by fixing some coordinates. This subspace proves to be useful to define scattering experiments where the rich and nontrivial dynamics of the problem is illustrated. We consider in particular trajectories which take very long before escaping or are trapped by consecutive collisions with the disk.
RESUMO
Discrete symmetries of a system are reflected in the properties of the shortest periodic orbits. By applying a recent method to extract these from the scaling of the fractal structure in scattering functions, we show how the symmetries can be extracted from scattering data simultaneously with the periods and the Lyapunov exponents. We pay particular attention to the change of scattering data under a small symmetry breaking.
RESUMO
El fenómeno clínico y el EEG de las convulsiones neonatales son diferentes a los observados en otras edades. Las crisis tónico clónicas generalizadas, las ausencias típicas y las crisis de marcha Jacksoniana no se observan habitualmente a esta edad, son bastante frecuentes las manifestaciones atípicas, enfatizando que cualquier evento transitorio bizarro, sobre todo si tiene tendencia a repetirse puede ser una manifestación convulsiva. Las causas son el completo desarrollo neuroanatómico y neurofisiológico cerecbral, debido a que las ramificaciones dendríticas y axonales están incopletamente desarrolladas, la mielinización está limitada a una pocas vías que no incluye las comisuras interhemisféricas y los receptores inhibidores y excitadores, si bien están presentes, están incopletamente desarrollados
Assuntos
Recém-Nascido , Doenças e Anormalidades Congênitas, Hereditárias e Neonatais , Convulsões , ParaguaiRESUMO
El fenómeno clínico y el EEG de las convulsiones neonatales son diferentes a los observados en otras edades. Las crisis tónico clónicas generalizadas, las ausencias típicas y las crisis de marcha Jacksoniana no se observan habitualmente a esta edad, son bastante frecuentes las manifestaciones atípicas, enfatizando que cualquier evento transitorio bizarro, sobre todo si tiene tendencia a repetirse puede ser una manifestación convulsiva. Las causas son el completo desarrollo neuroanatómico y neurofisiológico cerecbral, debido a que las ramificaciones dendríticas y axonales están incopletamente desarrolladas, la mielinización está limitada a una pocas vías que no incluye las comisuras interhemisféricas y los receptores inhibidores y excitadores, si bien están presentes, están incopletamente desarrollados
