Universality in active chaos

Many examples of chemical and biological processes take place in large-scale environmental flows. Such flows generate filamental patterns which are often fractal due to the presence of chaos in the underlying advection dynamics. In such processes, hydrodynamical stirring strongly couples into the reactivity of the advected species and might thus make the traditional treatment of the problem through partial differential equations difficult. Here we present a simple approach for the activity in in-homogeneously stirred flows. We show that the fractal patterns serving as skeletons and catalysts lead to a rate equation with a universal form that is independent of the flow, of the particle properties, and of the details of the active process. One aspect of the universality of our appraoch is that it also applies to reactions among particles of finite size (so-called inertial particles).Comment: 10 page

From electrons to Janskys: Full stokes polarized radiative transfer in 3D relativistic particle-in-cell jet simulations

The underlying plasma composition of relativistic extragalactic jets remains largely unknown. Relativistic magnetohydrodynamic (RMHD) models are able to reproduce many of the observed macroscopic features of these outflows. The nonthermal synchrotron emission detected by very long baseline interferometric (VLBI) arrays, however, is a by-product of the kinetic-scale physics occurring within the jet, physics that is not modeled directly in most RMHD codes. This paper attempts to discern the radiative differences between distinct plasma compositions within relativistic jets using small-scale 3D relativistic particle-in-cell (PIC) simulations. We generate full Stokes imaging of two PIC jet simulations, one in which the jet is composed of an electron-proton ($e^{-}$-$p^{+}$) plasma (i.e., a normal plasma jet), and the other in which the jet is composed of an electron-positron ($e^{-}$-$e^{+}$) plasma (i.e., a pair plasma jet). We examined the differences in the morphology and intensity of the linear polarization (LP) and circular polarization (CP) emanating from these two jet simulations. We find that the fractional level of CP emanating from the $e^{-}$-$p^{+}$ plasma jet is orders of magnitude larger than the level emanating from an $e^{-}$-$e^{+}$ plasma jet of a similar speed and magnetic field strength. In addition, we find that the morphology of both the linearly and circularly polarized synchrotron emission is distinct between the two jet compositions. We also demonstrate the importance of slow-light interpolation and we highlight the effect that a finite light-crossing time has on the resultant polarization when ray-tracing through relativistic plasma.Comment: 21 pages, 13 figures; accepted for publication in A&

Report of CE on Metadata Adaptation – Integration

In this document the Metadata Adaptation tool presented at the Pattaya meeting has been validated, with a slightly adjusted syntax and semantics. An alternative syntax has also been proposed so as to be combined with the adaptation hint DS. This tool supports adaptation operations such as metadata integration. The presented scheme includes two descriptors, named AverageValue and InvariantProperties, that can be efficiently used by an integration engine in order to improve the quality of the integrated final description and to speed up the whole integration process. Examples and experiment results are given to support the validation of the proposed tool

Report of CE on Metadata Adaptation – Integration

This paper summarize the final results of the CE on MPEG-21 Digital Item Adaptation – Integration. The CE was started at the Shanghai meeting (see document N5182) and due to the fact that not all the expected goals were achieved the CE has been extended to the Pattaya meeting (see document N5362). In the original work plan definition, the principal objectives to better evaluate if the current DIA Metadata Adaptability tools can fully support the integration of multiple MPEG-7 descriptions of a given content. The main contribution of this CE is an enhanced implementation of the metadata integration engine presented in the previous CE report and the definition of syntax and semantic for a new MPEG-21 DIA MetadataAdaptability tool useful in a metadata integration processes

Size variance of motor evoked potential at initiation of voluntary contraction in palsy of conversion disorder

ArticlePSYCHIATRY AND CLINICAL NEUROSCIENCES. 62(3): 286-292(2008)journal articl