16,472 research outputs found

    Massive galaxies with very young AGN

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    Gigahertz Peaked Spectrum (GPS) radio galaxies are generally thought to be the young counterparts of classical extended radio sources and live in massive ellipticals. GPS sources are vital for studying the early evolution of radio-loud AGN, the trigger of their nuclear activity, and the importance of feedback in galaxy evolution. We study the Parkes half-Jansky sample of GPS radio galaxies of which now all host galaxies have been identified and 80% has their redshifts determined (0.122 < z < 1.539). Analysis of the absolute magnitudes of the GPS host galaxies show that at z > 1 they are on average a magnitude fainter than classical 3C radio galaxies. This suggests that the AGN in young radio galaxies have not yet much influenced the overall properties of the host galaxy. However their restframe UV luminosities indicate that there is a low level of excess as compared to passive evolution models.Comment: To appear in the proceedings of "Formation and Evolution of Galaxy Bulges", IAUS 245; M. Bureau, E. Athanassoula & B. Barbuy, ed

    Guilt By Association: Proposition 21\u27s Gang Conspiracy Law Will Increase Youth. Violence in California

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    In March 2000, Proposition 21 enacted two revisions to the California Penal Code that dramatically altered the identification and punishment of fringe-offenders. First, a defendant need not be a member to be charged as an active participant in a gang. Second, and most importantly, Proposition 21 enacted a conspiracy law allowing gang participants to be charged as co-conspirators for any crime a fellow gang member commits. Under this newly created conspiracy theory, a juvenile may now be sentenced for a gang-related crime in which he did not participate

    A study of the parity-odd nucleon-nucleon potential

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    We investigate the parity-violating nucleon-nucleon potential as obtained in chiral effective field theory. By using resonance saturation we compare the chiral potential to the more traditional one-meson exchange potential. In particular, we show how parameters appearing in the different approaches can be compared with each other and demonstrate that analyses of parity violation in proton-proton scattering within the different approaches are in good agreement. In the second part of this work, we extend the parity-violating potential to next-to-next-to-leading order. We show that generally it includes both one-pion- and two-pion-exchange corrections, but the former play no significant role. The two-pion-exchange corrections depend on five new low-energy constants which only become important if the leading-order weak pion-nucleon constant hπh_\pi turns out to be very small.Comment: Published versio

    Ethical considerations in genomic research in South Africa

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    The conduct of genomic research in South Africa (SA) raises a number of ethical challenges that need to be addressed in its design and execution. These include, for example, considerations of consent, community engagement, stigmatisation, feedback of findings and ensuring that genomic research is of benefit to patients and researchers in SA. We provide an overview of the current debates on some of these issues and pointers for further reading
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