11,034 research outputs found

    Testing for Localisation Using Micro-Geographic Data

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    To study the detailed location patterns of industries, and particularly the tendency for industries to cluster relative to overallmanufacturing, we develop distance-based tests of localisation. In contrast to previous studies, our approach allows us to assess the statistical significance of departures from randomness. In addition, we treat space as continuous instead of using an arbitrary collection of geographical units. This avoids problems relating to scale and borders. We apply these tests to an exhaustive UK data set. For four-digit industries, we find that (i) only 51% of them are localised at a 5% confidence level, (ii) localisation takes place mostly at small scales below 50 kilometres, (iii) the degree of localisation is very skewed, and (iv) industries follow broad sectoral patterns with respect to localisation. Depending on the industry, smaller establishments can be the main drivers of both localisation and dispersion. Three-digit sectors show similar patterns of localisation at small scales as well as a tendency to localise at medium scales.localisation, clusters, K-density, spatial statistics

    Exploring the Detailed Location Patterns of UK Manufacturing Industries using Microgeographic Data

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    Using a point-patternmethodology, we explore a range of issues regarding the detailed location patterns of UKmanufacturing industries. In particular, we focus on the location of entrants and exiters vs. continuing establishments, domestic- vs. foreign-owned, large vs. small, and affiliated vs. independent. We also examine co-localisation between vertically-linked industries. Our analysis provides a set of new stylised facts and confirmation for others.Localisation, Clusters, K-density, Spatial Statistics.

    Free-energy model for fluid helium at high density

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    We present a semi-analytical free-energy model aimed at characterizing the thermodynamic properties of dense fluid helium, from the low-density atomic phase to the high-density fully ionized regime. The model is based on a free-energy minimization method and includes various different contributions representative of the correlations between atomic and ionic species and electrons. This model allows the computation of the thermodynamic properties of dense helium over an extended range of density and temperature and leads to the computation of the phase diagram of dense fluid helium, with its various temperature and pressure ionization contours. One of the predictions of the model is that pressure ionization occurs abruptly at \rho \simgr 10 g cm−3^{-3}, {\it i.e.} P\simgr 20 Mbar, from atomic helium He to fully ionized helium He2+^{2+}, or at least to a strongly ionized state, without He+^{+} stage, except at high enough temperature for temperature ionization to become dominant. These predictions and this phase diagram provide a guide for future dynamical experiments or numerical first-principle calculations aimed at studying the properties of helium at very high density, in particular its metallization. Indeed, the characterization of the helium phase diagram bears important consequences for the thermodynamic, magnetic and transport properties of cool and dense astrophysical objects, among which the solar and the numerous recently discovered extrasolar giant planets.Comment: Accepted for publication in Phys. Rev.
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