1,743 research outputs found

    Catalogue of the morphological features in the Spitzer Survey of Stellar Structure in Galaxies (S4^4G)

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    A catalogue of the morphological features for the complete Spitzer Survey of Stellar Structure in Galaxies (S4^4G), including 2352 nearby galaxies, is presented. The measurements are made using 3.6 ÎĽ\mum images, largely tracing the old stellar population; at this wavelength the effects of dust are also minimal. The measured features are the sizes, ellipticities, and orientations of bars, rings, ringlenses, and lenses. Measured in a similar manner are also barlenses (lens-like structures embedded in the bars), which are not lenses in the usual sense, being rather the more face-on counterparts of the boxy/peanut structures in the edge-on view. In addition, pitch angles of spiral arm segments are measured for those galaxies where they can be reliably traced. More than one pitch angle may appear for a single galaxy. All measurements are made in a human-supervised manner so that attention is paid to each galaxy. We used isophotal analysis, unsharp masking, and fitting ellipses to measured structures. We find that the sizes of the inner rings and lenses normalized to barlength correlate with the galaxy mass: the normalized sizes increase toward the less massive galaxies; it has been suggested that this is related to the larger dark matter content in the bar region in these systems. Bars in the low mass galaxies are also less concentrated, likely to be connected to the mass cut-off in the appearance of the nuclear rings and lenses. We also show observational evidence that barlenses indeed form part of the bar, and that a large fraction of the inner lenses in the non-barred galaxies could be former barlenses in which the thin outer bar component has dissolved.Comment: 17 pages, 12 figures, accepted for publication in A&

    Degree of Agility with an Ontology Based Application

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    Agility is a concept and practice with significant importance in managing projects and organizations, although it can also be very risky due to its degree of fuzziness if not properly defined. This research re-defines agility, emphasizes the need for ontologies for its management, and creates an application to measure the degree of agility inside an organization. In this research, various definitions of agility were gathered for the creation of ontology through a mind map revealing the characteristics of agility. As part of the Co-Evolute theory and methodology, the first agility ontology was developed as well as an application that evaluates the degree of agility in an organization. The application includes statements on which the respondents give opinions concerning the current and future desired states of agility and its importance in an evaluative way. The application has proven to operate well and extensive validation and verification of the tests runs will follow

    The geodesic X-ray transform with matrix weights

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    Consider a compact Riemannian manifold of dimension ≥3\geq 3 with strictly convex boundary, such that the manifold admits a strictly convex function. We show that the attenuated ray transform in the presence of an arbitrary connection and Higgs field is injective modulo the natural obstruction for functions and one-forms. We also show that the connection and the Higgs field are uniquely determined by the scattering relation modulo gauge transformations. The proofs involve a reduction to a local result showing that the geodesic X-ray transform with a matrix weight can be inverted locally near a point of strict convexity at the boundary, and a detailed analysis of layer stripping arguments based on strictly convex exhaustion functions. As a somewhat striking corollary, we show that these integral geometry problems can be solved on strictly convex manifolds of dimension ≥3\geq 3 having non-negative sectional curvature (similar results were known earlier in negative sectional curvature). We also apply our methods to solve some inverse problems in quantum state tomography and polarization tomography

    Matter X waves

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    We predict that an ultra-cold Bose gas in an optical lattice can give rise to a new form of condensation, namely matter X waves. These are non-spreading 3D wave-packets which reflect the symmetry of the Laplacian with a negative effective mass along the lattice direction, and are allowed to exist in the absence of any trapping potential even in the limit of non-interacting atoms. This result has also strong implications for optical propagation in periodic structuresComment: 5 pages, 2 figure

    Companions of Bright Barred Shapley Ames Galaxies

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    Companion galaxy environment for a subset of 78 bright and nearby barred galaxies from the Shapley Ames Catalog is presented. Among spiral barred galaxies there are Seyfert galaxies, galaxies with circumnuclear structures, galaxies not associated with any large scale galaxy cloud structure, galaxies with peculiar disk morphology (crooked arms) and galaxies with normal disk morphology; the list includes all Hubble types. The companion galaxy list includes number of companion galaxies within 20 diameters (D25), their Hubble type and projected separation distance. Additionally, companion environment was searched for four known active spiral galaxies, three of them are Seyfert galaxies, namely, NGC 1068, NGC 1097, NGC 5548 and one is a starburst galaxy, M82. Among the results obtained it is noted that the only spiral barred galaxy classified as Sy 1 in our list has no companions within a projected distance of 20 diameters; 6 out of 10 Sy 2 bar galaxies have no companions within 10 diamters, 6 out of 10 Sy 2 galaxies have one or more companions at projected separation distances between 10 and 20 diameters; 6 out of 12 galaxies with circumnuclear structures have 2 or more companions within 20 diametersComment: Accepted for publication in the Astronomical Journal, 40 pages incl. 3 figure

    Food dyes as an alternative tracking dye for DNA gel electrophoresis

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    The chemical, physical and toxicological effects on health of synthetic dyes that used as tracking dye in the electrophoresis requires seriously search about alternative tracking dye. The present study is aimed to find an alternative dye from safe food dyes which commonly used in food coloring. Five dyes were selected depending on their chemical properties and the availability in local market: Brilliant Blue FCF, Tartrazine, Sunset Yellow FCF, Carmoisine, and green traditional, three dyes were chosen to be mixed as loading buffer: Brilliant Blue FCF, Sunset Yellow FCF as a basic because it give the whole range size of most traditional loading buffers that available in market, and adding the Carmoisine as a new indicator for the bands less than 50bp, then mixed with DNA ladder in same percentage used with traditional loading buffers to clarify the effects of dyes on DNA, migrated on 1% agarose with loading buffer promega, results showed more clarity and highly readable separation of dyes and give wide range of size in the food loading mix than promega loading dye, by viewing the gel on UV light the DNA ladder were moved smoothly, bands separated effeminately on gel and in same rate of the DNA ladder that load with promega loading buffer which indicate no interaction between the food dyes and the DNA.Our studies show that the food dye can be used as a tracking dye in place of used synthetic dye. The procedure is found to be easy, practical, safely and reliable

    Natural history of preclinical IDDM in high risk siblings

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