Variations in the infrared brightness temperature of Saturn's rings

After adjusting for the decreased Sun-Saturn distance and adjusting all measurements to B ring values only, it is shown that the temperature variations are not as large as was thought. Various models of the multilayer agglomerate of particles of Saturn's rings are evaluated. It is recommended that the difference between the 11 and 20 micron brightness temperatures should be explained by a satisfactory model

The 'Celtic Tiger' - An Analysis of Ireland's Economic Growth Performance

Ireland; Europeanization; globalization; employment policy

Corporate Ownership in France: The Importance of History

This paper attempts to show the importance of history in influencing the structure of corporate ownership in France. The strong concentration of family ownership in France is traced to historical weaknesses in the money and capital markets that forced families to have recourse to self-financing. The weaknesses in the money and capital markets were greatly influenced by two eighteenth century financial traumas arising from John Law's Mississippi System (1716-20) and the financing of the French Revolution through the issue of the assignats in the 1790s.These financial traumas delayed significantly the emergence of banks and the capital market. Further historical factors influencing French corporate ownership were the changes in the inheritance law system at the start of the nineteenth century and, more recently, the emphasis on a pay-as-you-go pension system.

Information Theory and Knowledge-Gathering

It is assumed that human knowledge-building depends on a discrete sequential decision-making process subjected to a stochastic information transmitting environment. This environment randomly transmits Shannon type information-packets to the decision-maker, who examines each of them for relevancy and then determines his optimal choices. Using this set of relevant information-packets, the decision-maker adapts, over time, to the stochastic nature of his environment, and optimizes the subjective expected rate-of-growth of knowledge. The decision-maker’s optimal actions, lead to a decision function that involves his view of the subjective entropy of the environmental process and other important parameters at each stage of the process. Using this model of human behavior, one could create psychometric experiments using computer simulation and real decision-makers, to play programmed games to measure the resulting human performance.decision-making; dynamic programming; entropy; epistemology; information theory; knowledge; sequential processes; subjective probability

On the Anisotropic Nature of MRI-Driven Turbulence in Astrophysical Disks

The magnetorotational instability is thought to play an important role in enabling accretion in sufficiently ionized astrophysical disks. The rate at which MRI-driven turbulence transports angular momentum is related to both the strength of the amplitudes of the fluctuations on various scales and the degree of anisotropy of the underlying turbulence. This has motivated several studies of the distribution of turbulent power in spectral space. In this paper, we investigate the anisotropic nature of MRI-driven turbulence using a pseudo-spectral code and introduce novel ways to robustly characterize the underlying turbulence. We show that the general flow properties vary in a quasi-periodic way on timescales comparable to 10 inverse angular frequencies motivating the temporal analysis of its anisotropy. We introduce a 3D tensor invariant analysis to quantify and classify the evolution of the anisotropic turbulent flow. This analysis shows a continuous high level of anisotropy, with brief sporadic transitions towards two- and three-component isotropic turbulent flow. This temporal-dependent anisotropy renders standard shell-average, especially when used simultaneously with long temporal averages, inadequate for characterizing MRI-driven turbulence. We propose an alternative way to extract spectral information from the turbulent magnetized flow, whose anisotropic character depends strongly on time. This consists of stacking 1D Fourier spectra along three orthogonal directions that exhibit maximum anisotropy in Fourier space. The resulting averaged spectra show that the power along each of the three independent directions differs by several orders of magnitude over most scales, except the largest ones. Our results suggest that a first-principles theory to describe fully developed MRI-driven turbulence will likely have to consider the anisotropic nature of the flow at a fundamental level.Comment: 13 pages, 13 figures, submitted to Ap