339 research outputs found

    Proposal title - Search for C15 to C30 alkanes in lunar soils Final report

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    Lack of heavy alkanes in Apollo 11 and 12 lunar soil sample

    The polaroid image as photo-object

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    This article is part of a larger project on the cultural history of Polaroid photography and draws on research done at the Polaroid Corporate archive at Harvard and at the Polaroid company itself. It identifies two cultural practices engendered by Polaroid photography, which, at the point of its extinction, has briefly flared into visibility again. It argues that these practices are mistaken as novel but are in fact rediscoveries of practices that stretch back as many as five decades. The first section identifies Polaroid image-making as a photographic equivalent of what Tom Gunning calls the ‘cinema of attractions’. That is, the emphasis in its use is on the display of photographic technologies rather than the resultant image. Equally, the common practice, in both fine art and vernacular circles, of making composite pictures with Polaroid prints, draws attention from image content and redirects it to the photo as object

    Frequency metrology in quantum degenerate helium: Direct measurement of the 2 3S1 - 2 1S0 transition

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    Precision spectroscopy of simple atomic systems has refined our understanding of the fundamental laws of quantum physics. In particular, helium spectroscopy has played a crucial role in describing two-electron interactions, determining the fine-structure constant and extracting the size of the helium nucleus. Here we present a measurement of the doubly-forbidden 1557-nanometer transition connecting the two metastable states of helium (the lowest energy triplet state 2 3S1 and first excited singlet state 2 1S0), for which quantum electrodynamic and nuclear size effects are very strong. This transition is fourteen orders of magnitude weaker than the most predominantly measured transition in helium. Ultracold, sub-microkelvin, fermionic 3He and bosonic 4He atoms are used to obtain a precision of 8.10^{-12}, providing a stringent test of two-electron quantum electrodynamic theory and of nuclear few-body theory.Comment: 14 pages, 6 figure

    Airbnb and crime in Barcelona (Spain): testing the relationship using a geographically weighted regression

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    The existence of works proving the possible relationship empirically that Airbnb lodgings could have with crime in Spain is not known. This research analyzes the relationship between Airbnb lodgings and crimes against the properties and people in Barcelona’s neighbourhoods. To achieve this, we use an ordinary least squares regression model and a geographically weighted regression model. The results show a significant and positive relationship between the higher density of Airbnb lodgings and the higher crime rates in the neighbourhoods, especially of patrimonial nature. Divided by type of leased space, the Airbnb homes, in which the guest shares a room with other guests, show a higher relationship with crimes against property and people. The results of the local model show a spatial heterogeneity in all variables used, indicating the need to address non-stationary spatial processes that reveal hidden patterns. However, the only variable that shows statistically significant local variability is the total Airbnb lodgings variable. Finally, we discussed some unexpected results, proposing some future lines of research. © 2020 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group, on behalf of Nanjing Normal University

    The stop and search of minors: A 'vital police tool'?

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    Police stop and search powers have been widely criticized for the disproportionate manner in which members of black and ethnic minority communities are targeted. However, the use of such powers on minors in England and Wales has largely escaped comment, despite good evidence that such practices are harmful and counter-productive. Whilst data on the stop and search of under-10s and even toddlers has been reasonably widely reported by the mass media, there has been little interest in the welfare of older children who are subject to such police powers. Drawing on police data, qualitative research and information obtained through Freedom of Information requests, this article considers the relationship between potentially corrosive stop and search practices, young people’s use of public space and the question of vulnerability. It is concluded that policy and practice around the use of such powers should be amended to take account of the specific needs of individuals under the age of 18, and that children’s welfare should be a central consideration
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