142 research outputs found

    A new genetic lineage of Asparagopsis taxiformis (Rhodophyta) in the Mediterranean Sea: As the DNA barcoding indicates a recent Lessepsian introduction

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    Asparagopsis taxiformis (Delile) Trevisan is a red marine macroalga (Bonnemaisoniales, Rhodophyta) with high invasive potential and broad worldwide distribution. In the Mediterranean Sea, A. taxiformis was reported before the opening of the Suez Canal and is comprised of two different cryptic lineages, named L2 and L3. As for the Israeli Mediterranean Sea (IMS), A. taxiformis benthic populations have seemingly expanded with several large seasonal blooms recorded in recent years. However, neither ecology nor molecular substantial studies have been conducted for this particular geographical area. Increasing sampling intensity and geographical coverage may reveal new lineages or indicate human-mediated spread routes not only for A. taxiformis but for macroalgae in general. This approach is particularly important in areas such as the eastern Mediterranean Sea, which experiences intense biological invasion on a global scale. In this study, randomly samples specimens (n = 30) of A. taxiformis and preserved herbarium samples (n = 4) collected from the IMS in the past, were all barcoded and taxonomically identified using three molecular genetic markers (LSU, cox2-3 spacer, and rbcL). We found a cryptic lineage 4 (L4) of A. taxiformis first reported here for the Mediterranean Sea, and previously described for the western Indo-Pacific and Hawaii. Herbarium samples confirmed the presence of L4 as early as 2013. Comparative assessment of cox2-3 spacer marker indicates 100% similarity to sequenced L4 samples from Egypt in the Red Sea. The IMS cox2-3 spacer sequences differed from previously sequenced samples from the Mediterranean Sea by 2.3% and 3.9% bp, compared to L3 and L2 Mediterranean populations, respectively. Morphological inspections indicate monoecious L4 gametophytes which are larger than the L4 population reported previously from Hawaii. Altogether, our results strongly indicate a Lessepsian migration route for A. taxiformis L4 with yet unknown consequences for the local marine ecosystems

    Jet-Powered Molecular Hydrogen Emission from Radio Galaxies

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    H2 pure-rotational emission lines are detected from warm (100-1500 K) molecular gas in 17/55 (31% of) radio galaxies at redshift z<0.22 observed with the Spitzer IR Spectrograph. The summed H2 0-0 S(0)-S(3) line luminosities are L(H2)=7E38-2E42 erg/s, yielding warm H2 masses up to 2E10 Msun. These radio galaxies, of both FR radio morphological types, help to firmly establish the new class of radio-selected molecular hydrogen emission galaxies (radio MOHEGs). MOHEGs have extremely large H2 to 7.7 micron PAH emission ratios: L(H2)/L(PAH7.7) = 0.04-4, up to a factor 300 greater than the median value for normal star-forming galaxies. In spite of large H2 masses, MOHEGs appear to be inefficient at forming stars, perhaps because the molecular gas is kinematically unsettled and turbulent. Low-luminosity mid-IR continuum emission together with low-ionization emission line spectra indicate low-luminosity AGNs in all but 3 radio MOHEGs. The AGN X-ray emission measured with Chandra is not luminous enough to power the H2 emission from MOHEGs. Nearly all radio MOHEGs belong to clusters or close pairs, including 4 cool core clusters (Perseus, Hydra, A 2052, and A 2199). We suggest that the H2 in radio MOHEGs is delivered in galaxy collisions or cooling flows, then heated by radio jet feedback in the form of kinetic energy dissipation by shocks or cosmic rays.Comment: ApJ in press, 40 pages, 18 figures, 14 table

    The Outer Halo of the Nearest Giant Elliptical : A VLT/VIMOS Survey of the Resolved Stellar Populations in Centaurus A to 85 kpc

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    This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society. © 2013 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.We present the first deep survey of resolved stellar populations in the remote outer halo of our nearest giant elliptical (gE), Centaurus A (D=3.8 Mpc). Using the VIMOS/VLT optical camera, we obtained deep photometry for four fields along the major and minor axes at projected elliptical radii of ~30-85 kpc (corresponding to ~5-14 R_{eff}). We use resolved star counts to map the spatial and colour distribution of red giant branch (RGB) stars down to ~2 magnitudes below the RGB tip. We detect an extended halo out to the furthermost elliptical radius probed (~85 kpc or ~14 R_{eff}), demonstrating the vast extent of this system. We detect a localised substructure in these parts, visible in both (old) RGB and (intermediate-age) luminous asymptotic giant branch stars, and there is some evidence that the outer halo becomes more elliptical and has a shallower surface brightness profile. We derive photometric metallicity distribution functions for halo RGB stars and find relatively high median metallicity values ([Fe/H]_{med} -0.9 to -1.0 dex) that change very little with radius over the extent of our survey. Radial metallicity gradients are measured to be ~-0.002 to -0.004 dex/kpc and the fraction of metal-poor stars (defined as [Fe/H]Peer reviewe

    Ordered Incidence geometry and the geometric foundations of convexity theory

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    An Ordered Incidence Geometry, that is a geometry with certain axioms of incidence and order, is proposed as a minimal setting for the fundamental convexity theorems, which usually appear in the context of a linear vector space, but require only incidence, order (and for separation, completeness), and none of the linear structure of a vector space.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42995/1/22_2005_Article_BF01227810.pd

    Magnesium nebulization utilization in management of pediatric asthma (MagNUM PA) trial: study protocol for a randomized controlled trial

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    Partners No More: Relational Transformation and the Turn to Litigation in Two Conservationist Organizations

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    The rise in litigation against administrative bodies by environmental and other political interest groups worldwide has been explained predominantly through the liberalization of standing doctrines. Under this explanation, termed here the floodgate model, restrictive standing rules have dammed the flow of suits that groups were otherwise ready and eager to pursue. I examine this hypothesis by analyzing processes of institutional transformation in two conservationist organizations: the Sierra Club in the United States and the Society for the Protection of Nature in Israel (SPNI). Rather than an eagerness to embrace newly available litigation opportunities, as the floodgate model would predict, the groups\u27 history reveals a gradual process of transformation marked by internal, largely intergenerational divisions between those who abhorred conflict with state institutions and those who saw such conflict as not only appropriate but necessary to the mission of the group. Furthermore, in contrast to the pluralist interactions that the floodgate model imagines, both groups\u27 relations with pertinent agencies in earlier eras better accorded with the partnership-based corporatist paradigm. Sociolegal research has long indicated the importance of relational distance to the transformation of interpersonal disputes. I argue that, at the group level as well, the presence or absence of a (national) partnership-centered relationship determines propensities to bring political issues to court. As such, well beyond change in groups\u27 legal capacity and resources, current increases in levels of political litigation suggest more fundamental transformations in the structure and meaning of relations between citizen groups and the state

    Data Mining and Knowledge Discovery: An Analytical Investigation

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    The construction of authenticity in the creative process:Lessons from choreographers of contemporary dance

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    The literature on authenticity of cultural production has systematically examined the perceived authenticity of both the producer and the cultural product but not of the creative process. This study aims to address this lacuna, adopting Carroll and Wheaton's typology of type and moral authenticity to examine how contemporary dance choreographers construct authenticity during the creation of a new choreography. Our analysis of data from 23 contemporary dance companies reveals that the two meanings of authenticity dynamically reconstitute one another in the creative process. First, choreographers construct moral authenticity through transformation of form, deconstructing established artistic dance forms and introducing new movements from a bricolage of techniques. Second, they construct type authenticity through wrapping expression, facilitating the deconstruction of the values attached to the bricolage of techniques into artistic dance aesthetics. Finally, choreographers evoke both moral and type authenticity through a creative process of reconstruction. Our noteworthy finding reveals how the construction of authenticity in the process of creating a new choreography, and the dynamics between the two meanings of authenticity, serve significantly as a means of communication among the involved actors, thereby enabling the creative process

    A recourse certainty equivalent for decisions under uncertainty

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    http://deepblue.lib.umich.edu/bitstream/2027.42/3544/5/bal7898.0001.001.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/3544/4/bal7898.0001.001.tx
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