4,788 research outputs found

    Time Dilation and Quasar Variability

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    The timescale of quasar variability is widely expected to show the effects of time dilation. In this paper we analyse the Fourier power spectra of a large sample of quasar light curves to look for such an effect. We find that the timescale of quasar variation does not increase with redshift as required by time dilation. Possible explanations of this result all conflict with widely held consensus in the scientific community.Comment: 6 pages including 3 figures. Accepted for publication in ApJ Letter

    Modelling of droplet impacts on dry and wet surfaces using depth-averaged form

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    An efficient time-adaptive multigrid algorithm is used to solve a range of normal and oblique droplet impacts on dry surfaces and liquid films using the Depth-Averaged Form (DAF) method of the governing unsteady Navier–Stokes equations. The dynamics of a moving three-phase contact line on dry surfaces is predicted by a precursor film model. The method is validated against a variety of experimental results for droplet impacts, looking at factors such as crown height and diameter, spreading diameter and splashing for a range of Weber, Reynolds and Froude numbers along with liquid film thicknesses and impact angles. It is found that, while being a computationally inexpensive methodology, the DAF method produces accurate predictions of the crown and spreading diameters as well as conditions for splash, however, underpredicts the crown height as the vertical inertia is not included in the model

    Reducing Plastic Pollution in the Ocean: MycoBuoys as a Potential Solution

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    Natural mushroom mycelium-based MycoBuoys are an alternative to ubiquitous plastic flotation devices used in Maine aquaculture, fisheries and harbors. They fit perfectly into a circular economic model where natural resources are borrowed for a specific purpose and are returned as elements at the end of product life. MycoBuoys may be composted or used as mulch where 100% of the material enhances soil nutrients upon decomposition. In contrast to this cradle-to-cradle product, currently ubiquitous Stryofoam buoys have expensive end life costs in terms of ecosystem and organismal health consequences. Styrene is a known carcinogen, and the foam particles degrade into smaller fragments, but never go away. With the end of subsidies for fossil fuels (necessary to reach climate resilient goals), and with extended producer responsibility (EPR) for all manufactured products, plastic foams used for buoys will no longer be economically or environmentally feasible

    High Multiplicity Searches at the LHC Using Jet Masses

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    This article introduces a new class of searches for physics beyond the Standard Model that improves the sensitivity to signals with high jet multiplicity. The proposed searches gain access to high multiplicity signals by reclustering events into large-radius, or "fat," jets and by requiring that each event has multiple massive jets. This technique is applied to supersymmetric scenarios in which gluinos are pair-produced and then subsequently decay to final states with either moderate quantities of missing energy or final states without missing energy. In each of these scenarios, the use of jet mass improves the estimated reach in gluino mass by 20 % to 50 % over current LHC searches.Comment: 9 pages, 6 figures; v3 corrects a few small typo

    The racist bodily imaginary: the image of the body-in-pieces in (post)apartheid culture

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    This paper outlines a reoccurring motif within the racist imaginary of (post)apartheid culture: the black body-in-pieces. This disturbing visual idiom is approached from three conceptual perspectives. By linking ideas prevalent in Frantz Fanon’s description of colonial racism with psychoanalytic concepts such as Lacan’s notion of the corps morcelĂ©, the paper offers, firstly, an account of the black body-in-pieces as fantasmatic preoccupation of the (post)apartheid imaginary. The role of such images is approached, secondly, through the lens of affect theory which eschews a representational ‘reading’ of such images in favour of attention to their asignifying intensities and the role they play in effectively constituting such bodies. Lastly, Judith Butler’s discussion of war photography and the conditions of grievability introduces an ethical dimension to the discussion and helps draw attention to the unsavory relations of enjoyment occasioned by such images

    A Synoptic, Multiwavelength Analysis of a Large Quasar Sample

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    We present variability and multi-wavelength photometric information for the 933 known quasars in the QUEST Variability Survey. These quasars are grouped into variable and non-variable populations based on measured variability confidence levels. In a time-limited synoptic survey, we detect an anti-correlation between redshift and the likelihood of variability. Our comparison of variability likelihood to radio, IR, and X-ray data is consistent with earlier quasar studies. Using already-known quasars as a template, we introduce a light curve morphology algorithm that provides an efficient method for discriminating variable quasars from periodic variable objects in the absence of spectroscopic information. The establishment of statistically robust trends and efficient, non-spectroscopic selection algorithms will aid in quasar identification and categorization in upcoming massive synoptic surveys. Finally, we report on three interesting variable quasars, including variability confirmation of the BL Lac candidate PKS 1222+037.Comment: AJ, accepted for publication 15 Dec 200

    Shakespeare 1564-1964

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    A Guide to an Exhibition of Rare Books Relating to Shakespeare Upon the Occasion of the Quadricentennial of His Birth Rare Book Room, Lehigh University Library, Bethlehem, Pa. April 1, 196
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