4,581 research outputs found

    Return to Driving and a Clinical Measure of Reaction Time

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147100/1/pmr2156.pd

    Classification and analysis of emission-line galaxies using mean field independent component analysis

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    We present an analysis of the optical spectra of narrow emission-line galaxies, based on mean field independent component analysis (MFICA). Samples of galaxies were drawn from the Sloan Digital Sky Survey (SDSS) and used to generate compact sets of `continuum' and `emission-line' component spectra. These components can be linearly combined to reconstruct the observed spectra of a wider sample of galaxies. Only 10 components - five continuum and five emission line - are required to produce accurate reconstructions of essentially all narrow emission-line galaxies; the median absolute deviations of the reconstructed emission-line fluxes, given the signal-to-noise ratio (S/N) of the observed spectra, are 1.2-1.8 sigma for the strong lines. After applying the MFICA components to a large sample of SDSS galaxies we identify the regions of parameter space that correspond to pure star formation and pure active galactic nucleus (AGN) emission-line spectra, and produce high S/N reconstructions of these spectra. The physical properties of the pure star formation and pure AGN spectra are investigated by means of a series of photoionization models, exploiting the faint emission lines that can be measured in the reconstructions. We are able to recreate the emission line strengths of the most extreme AGN case by assuming the central engine illuminates a large number of individual clouds with radial distance and density distributions, f(r) ~ r^gamma and g(n) ~ n^beta, respectively. The best fit is obtained with gamma = -0.75 and beta = -1.4. From the reconstructed star formation spectra we are able to estimate the starburst ages. These preliminary investigations serve to demonstrate the success of the MFICA-based technique in identifying distinct emission sources, and its potential as a tool for the detailed analysis of the physical properties of galaxies in large-scale surveys.Comment: MNRAS accepted. 29 pages, 24 figures, 3 table

    Litigation, liberty, and legitimation: The experience of the Church of Scientology in Australian Law

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    Freedom of religion, the paradigm of freedom of conscience, is of the essence of a free society. The chief function in the law of a definition of religion is to mark out an area within which a person subject to the law is free to believe and to act in accordance with his belief without legal restraint

    The European Court of Human Rights and minority religions: messages generated and messages received

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    This contribution introduces a collection of studies focused on engagements of religious minorities with the European Court of Human Rights (ECtHR). Setting out first the global importance of the ECtHR as a standard setter in the protection of the rights of religious minorities, the text goes on to introduce the ten contributions that together make up the present special issue on the European Court of Human Rights and Religious Minorities. Beyond briefly summar- ising the contexts of the special issue, this contribution indicates that the first part of the special issue entails critical assessments of some of the Court’s case law dealing with religious minority claims (exploring on their clarity and consistency – or lack thereof – and controversiality), and that the second part offers insight into the grassroots level impact of the Court’s case law on religious minority claims. It explains how each of these contributions deepens our understanding of the ECtHR in its approach to and impact on religious minorities. And it introduces the fact that, rather uniquely, this collection of texts offers a rare vantage point on the ‘circle of life’ of the Court’s case law on religious minorities

    Interpreting the Ionization Sequence in AGN Emission-Line Spectra

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    We investigate the physical cause of the great range in the ionization level seen in the spectra of narrow lined active galactic nuclei (AGN). Mean field independent component analysis identifies examples of individual SDSS galaxies whose spectra are not dominated by emission due to star formation (SF), which we designate as AGN. We assembled high S/N ratio composite spectra of a sequence of these AGN defined by the ionization level of their narrow-line regions (NLR), extending down to very low-ionization cases. We used a local optimally emitting cloud (LOC) model to fit emission-line ratios in this AGN sequence. These included the weak lines that can be measured only in the co-added spectra, providing consistency checks on strong line diagnostics. After integrating over a wide range of radii and densities our models indicate that the radial extent of the NLR is the major parameter in determining the position of high to moderate ionization AGN along our sequence, providing a physical interpretation for their systematic variation. Higher ionization AGN contain optimally emitting clouds that are more concentrated towards the central continuum source than in lower ionization AGN. Our LOC models indicate that for the objects that lie on our AGN sequence, the ionizing luminosity is anticorrelated with the NLR ionization level, and hence anticorrelated with the radial concentration and physical extent of the NLR. A possible interpretation that deserves further exploration is that the ionization sequence might be an age sequence where low ionization objects are older and have systematically cleared out their central regions by radiation pressure. We consider that our AGN sequence instead represents a mixing curve of SF and AGN spectra, but argue that while many galaxies do have this type of composite spectra, our AGN sequence appears to be a special set of objects with negligible SF excitation.Comment: 57 pages; 18 figures, accepted by MNRA
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