9,887 research outputs found

    Expectation adjustment in the housing market: insights from the Scottish auction system

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    This paper examines price expectation adjustment of house buyers and sellers to rapid changes in the housing market using data from Scotland where houses are sold through 'first-price sealed-bid' auctions. These auctions provide more information on market signals, incentives and the behaviour of market participants than private treaty sales. This paper therefore provides a theoretical framework for analysing revealed preference data generated from these auctions. We specifically focus on the analysis of the selling to asking price difference, the 'bid-premium'. The bid-premium is shown to be affected by expectations of future price movements, market duration and high bidding frequency. The bid-premium reflects consumers' expectations, adapting to market conditions more promptly than asking price setting behaviour and final sale prices. The volatile conditions of the recent housing market bubble are fully reflected in the bid-premium, whereas the asking and sale prices are much less prone to rapid movements

    How scientists and physicians use Twitter during a medical congress

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    OBJECTIVES: During medical congresses Twitter allows discussions to disseminate beyond the congress hall and reach a wider audience. Insights into the dynamics of social media interactions during congresses, dissemination of scientific information and the determinants of a successful tweet may allow us to better understand social media's role in science communication. METHODS: We retrospectively extracted social media data during the European Congress of Clinical Microbiology and Infectious Diseases (ECCMID) 2017 and 2018 using NodeXL. We compared social media activity during these two congresses. Subsequently, we conducted in-depth analyses to identify the components of a successful tweet and multivariable analysis to assess independent factors associated with retweet activity. RESULTS: In 2018, approximately 13,000 delegates attended ECCMID, but only 591 Twitter accounts actively tweeted about the congress. Although fewer tweets were posted in 2018 compared to 2017 (4,213 vs 4,657, respectively), ECCMID2018 generated a 63% increase in the total number of retweets (p <0.001). According to multivariable logistic regression analysis, using multimedia, URL or hashtags and mentioning other Twitter account(s) were independently associated with retweet success. Mentioning of other users and use of multimedia were the only consistent predictors of retweets irrespective of the number of followers. CONCLUSIONS: A substantial increase in retweet activity and a modest increase in the number of influential Twitter accounts were observed between two successive congresses. Dissemination of scientific messages is more successful when connected accounts are actively involved in social media activity, and social media posts constitute the right combination of components.PostprintPeer reviewe

    Mobile radio interferometric geodetic systems

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    Operation of the Astronomical Radio Interferometric Earth Surveying (ARIES) in a proof of concept mode is discussed. Accuracy demonstrations over a short baseline, a 180 km baseline, and a 380 km baseline are documented. Use of ARIES in the Sea Slope Experiment of the National Geodetic Survey to study the apparent differences between oceanographic and geodetic leveling determinations of the sea surface along the Pacific Coast is described. Intergration of the NAVSTAR Global Positioning System and a concept called SERIES (Satellite Emission Radio Interferometric Earth Surveying) is briefly reviewed

    Deconfined Fermions but Confined Coherence?

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    The cuprate superconductors and certain organic conductors exhibit transport which is qualitatively anisotropic, yet at the same time other properties of these materials strongly suggest the existence of a Fermi surface and low energy excitations with substantial free electron character. The former of these features is very difficult to account for if the material possesses three dimensional coherence, while the latter is inconsistent with a description based on a two dimensional fixed point. We therefore present a new proposal for these materials in which they are categorized by a fixed point at which transport in one direction is not renormalization group irrelevant, but is intrinsically incoherent, i.e. the incoherence is present in a pure system, at zero temperature. The defining property of such a state is that single electron coherence is confined to lower dimensional subspaces (planes or chains) so that it is impossible to observe interference effects between histories which involve electrons moving between these subspaces.Comment: 31 pages, REVTEX, 3 eps figures, epsf.tex macr

    Oscillatory surface dichroism of an insulating topological insulator Bi2Te2Se

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    Using circular dichroism-angle resolved photoemission spectroscopy (CD-ARPES), we report a study of the effect of angular momentum transfer between polarized photons and topological surface states on the surface of highly bulk insulating topological insulator Bi2Te2Se. The photoelectron dichroism is found to be strongly modulated by the frequency of the helical photons including a dramatic sign-flip. Our results suggest that the observed dichroism and its sign-flip are consequences of strong coupling between the photon field and the spin-orbit nature of the Dirac modes on the surface. Our studies reveal the intrinsic dichroic behavior of topological surface states and point toward the potential utility of bulk insulating topological insulators in device applications.Comment: 5 pages, 4 figure

    Strongly Coupled Matter-Field and Non-Analytic Decay Rate of Dipole Molecules in a Waveguide

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    The decay rate \gam of an excited dipole molecule inside a waveguide is evaluated for the strongly coupled matter-field case near a cutoff frequency \ome_c without using perturbation analysis. Due to the singularity in the density of photon states at the cutoff frequency, we find that \gam depends non-analytically on the coupling constant \ggg as 4/3\ggg^{4/3}. In contrast to the ordinary evaluation of \gam which relies on the Fermi golden rule (itself based on perturbation analysis), \gam has an upper bound and does not diverge at \ome_c even if we assume perfect conductance in the waveguide walls. As a result, again in contrast to the statement found in the literature, the speed of emitted light from the molecule does not vanish at \ome_c and is proportional to c2/3c\ggg^{2/3} which is on the order of 10310410^3 \sim 10^4 m/s for typical dipole molecules.Comment: 4 pages, 2 figure
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