Capture and escape in the elliptic restricted three-body problem

Several families of irregular moons orbit the giant planets. These moons are thought to have been captured into planetocentric orbits after straying into a region in which the planet's gravitation dominates solar perturbations (the Hill sphere). This mechanism requires a source of dissipation, such as gas-drag, in order to make capture permanent. However, capture by gas-drag requires that particles remain inside the Hill sphere long enough for dissipation to be effective. Recently we have proposed that in the circular restricted three-body problem particles may become caught up in `sticky' chaotic layers which tends to prolong their sojourn within the planet's Hill sphere thereby assisting capture. Here we show that this mechanism survives perturbations due to the ellipticity of the planet's orbit. However, Monte Carlo simulations indicate that the planet's ability to capture moons decreases with increasing orbital eccentricity. At the actual Jupiter's orbital eccentricity, this effects in approximately an order of magnitude lower capture probability than estimated in the circular model. Eccentricities of planetary orbits in the Solar System are moderate but this is not necessarily the case for extrasolar planets which typically have rather eccentric orbits. Therefore, our findings suggest that these extrasolar planets are unlikely to have substantial populations of irregular moons.Comment: This is a preprint of an Article accepted for publication in Monthly Notices of the Royal Astronomical Society, (C) 2004 The Royal Astronomical Societ

Independent components in spectroscopic analysis of complex mixtures

We applied two methods of "blind" spectral decomposition (MILCA and SNICA) to quantitative and qualitative analysis of UV absorption spectra of several non-trivial mixture types. Both methods use the concept of statistical independence and aim at the reconstruction of minimally dependent components from a linear mixture. We examined mixtures of major ecotoxicants (aromatic and polyaromatic hydrocarbons), amino acids and complex mixtures of vitamins in a veterinary drug. Both MICLA and SNICA were able to recover concentrations and individual spectra with minimal errors comparable with instrumental noise. In most cases their performance was similar to or better than that of other chemometric methods such as MCR-ALS, SIMPLISMA, RADICAL, JADE and FastICA. These results suggest that the ICA methods used in this study are suitable for real life applications. Data used in this paper along with simple matlab codes to reproduce paper figures can be found at http://www.klab.caltech.edu/~kraskov/MILCA/spectraComment: 22 pages, 4 tables, 6 figure

Technology Diffusion in the Coal Mining Industry of the USSR: An Interim Assessment

Over many years IIASA has been involved in energy studies, coal was always an important research topic at all levels from resource assessment, study of potential future coal supply to the analysis of environmental impacts resulting from expanded coal utilization. The present paper presents an analysis of technological change in the coal mining industry of the USSR. It describes within a quantitative framework first the evolution of the coal mining industry in general, based on macro indicators of output, production intensity and labor productivity. Then it describes qualitatively the different historical phases of development and introduction of new technologies into the sector and concludes by quantifying the historical trajectories of new technologies diffusion, using standard models of technological diffusion and substitution. The paper not only provides insight into the dynamics of the technological change in the coal mining industry of the USSR, but addresses also some of the effects of theses developments. Finally some tentative conclusions with respect to future evolution in the industry are outlined. Other IIASA studies have addressed similar changes in the technology of coal mining in the USA the UK and the FRG, albeit in not such great detail. These results could be used in conjunction with the present study for a subsequent cross national comparison of technological trends in the coal mining industry. The present paper is the product of a continued and very fruitful cooperation between IIASA and the Academy of the National Economy at the Council of Ministers of the USSR. It adds to the productivity of this cooperation, which will continue in the future

Technology Diffusion in the Coal Mining Industry of the USSR: An Interim Assessment

Over many years IIASA has been involved in energy studies, coal was always an important research topic at all levels from resource assessment, study of potential future coal supply to the analysis of environmental impacts resulting from expanded coal utilization. The present paper presents an analysis of technological change in the coal mining industry of the USSR. It describes within a quantitative framework first the evolution of the coal mining industry in general, based on macro indicators of output, production intensity and labor productivity. Then it describes qualitatively the different historical phases of development and introduction of new technologies into the sector and concludes by quantifying the historical trajectories of new technologies diffusion, using standard models of technological diffusion and substitution. The paper not only provides insight into the dynamics of the technological change in the coal mining industry of the USSR, but addresses also some of the effects of theses developments. Finally some tentative conclusions with respect to future evolution in the industry are outlined. Other IIASA studies have addressed similar changes in the technology of coal mining in the USA the UK and the FRG, albeit in not such great detail. These results could be used in conjunction with the present study for a subsequent cross national comparison of technological trends in the coal mining industry. The present paper is the product of a continued and very fruitful cooperation between IIASA and the Academy of the National Economy at the Council of Ministers of the USSR. It adds to the productivity of this cooperation, which will continue in the future