1,777 research outputs found

    Independent components in spectroscopic analysis of complex mixtures

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    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

    Capture and escape in the elliptic restricted three-body problem

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    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

    Subject Content of Culturological Knowledge

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    The article considers the issues of subject characteristics of culture supplementing its object content. The author notes that importance of implementing subject content of culturological knowledge is dictated by necessity for overcoming a one-dimensional consideration of culture. Therefore, the author proves the importance of realizing its duality in the aspect of adjectival and the substantive characteristics dictating communication between subject and object content of culture. Keywords: social and scientific cultural study, humanitarian cultural study, subject content of culture, object content of culture
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