16,053 research outputs found

    Using a GIS for Real Estate Market Analysis: The Problem of Spatially Aggregated Data

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    Many databases used for real estate market analysis are not available at the address level. For example, information on employment and unemployment may be available only for labor market areas; and Census data is typically tabulated for blocks or higher levels of spatial aggregation. A Geographic Information System (GIS) associates these spatially aggregated data with the geographical center of the area. This poses special problems when we use a GIS to evaluate linkages between supply and demand. This article presents some solutions to this problem; methods that are relatively easy to implement on a GIS are emphasized. A GIS can be used to calculate a theoretical average travel distance to the population in the geographical area. We propose ways to determine when these theoretical distances are inadequate approximations; and we provide alternatives for these situations.

    XMM-Newton observations of five INTEGRAL sources located towards the Scutum Arm

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    Results are presented for XMM-Newton observations of five hard X-ray sources discovered by INTEGRAL in the direction of the Scutum Arm. Each source received more than 20 ks of effective exposure time. We provide refined X-ray positions for all five targets enabling us to pinpoint the most likely counterpart in optical/infrared archives. Spectral and timing information (much of which are provided for the first time) allow us to give a firm classification for IGR J18462-0223 and to offer tentative classifications for the others. For IGR J18462-0223, we discovered a coherent pulsation period of 997+-1 s which we attribute to the spin of a neutron star in a highly-obscured (nH = 2e23 /cm2) high-mass X-ray binary (HMXB). This makes IGR J18462-0223 the seventh supergiant fast X-ray transient (SFXT) candidate with a confirmed pulsation period. IGR J18457+0244 is a highly-absorbed (nH = 8e23 /cm2) source in which the possible detection of an iron line suggests an active galactic nucleus (AGN) of type Sey-2 situated at z = 0.07(1). A periodic signal at 4.4 ks could be a quasi-periodic oscillation which would make IGR J18457+0244 one of a handful of AGN in which such features have been claimed, but a slowly-rotating neutron star in an HMXB can not be ruled out. IGR J18482+0049 represents a new obscured HMXB candidate with nH = 4e23 /cm2. We tentatively propose that IGR J18532+0416 is either an AGN or a pulsar in an HMXB system. The X-ray spectral properties of IGR J18538-0102 are consistent with the AGN classification that has been proposed for this source.Comment: 15 pages, 9 figures, 4 tables: accepted for publication in Ap

    A distributional checklist of the spider wasps (Hymenoptera: Pompilidae) of Florida

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    The Florida fauna of Pompilidae is investigated and a total of 115 species are recorded. Among them, 30 are new records for the state. The species and subspecies are presented by subfamily and tribe accompanied by county-based distributional accounts for each of the lower taxa.Se investiga la fauna de Pompilidae de Florida, reportándose un total de 115 especies. De estas, 30 especies son nuevos registros para el estado. Se presenta la subfamilia y tribu correspondiente a las especies y subespecies. La distribución en condados se enumera para los taxones de más bajo rango

    Should UI Benefits Really Fall over Time?

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    The issue of whether unemployment benefits should increase or decrease over the unemployment spell is analyzed in an analytically tractable model allowing moral hazard, adverse selection and hidden savings. Analytical results show that when the search productivity of unemployed is constant over the unemployment spell, benefits should typically increase or be constant. The only exception is when there is moral hazard and no hidden savings. In general, adverse selection problems calls for increasing benefits, moral hazard problems for constant benefits and decreasing search productivity for decreasing benefits.unemployment benefits, search, moral hazard, adverse selection

    OVCS Newsletter April 2014

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    PEM-West trajectory climatology and photochemical model sensitivity study prepared using retrospective meteorological data

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    Trajectory and photochemical model calculations based on retrospective meteorological data for the operations areas of the NASA Pacific Exploratory Mission (PEM)-West mission are summarized. The trajectory climatology discussed here is intended to provide guidance for flight planning and initial data interpretation during the field phase of the expedition by indicating the most probable path air parcels are likely to take to reach various points in the area. The photochemical model calculations which are discussed indicate the sensitivity of the chemical environment to various initial chemical concentrations and to conditions along the trajectory. In the post-expedition analysis these calculations will be used to provide a climatological context for the meteorological conditions which are encountered in the field

    Inequality and Mobility

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    Acknowledging that wage inequality and intergenerational mobility are strongly interrelated, this paper presents a model in which both are jointly determined. The model enables us to study how inequality and mobility are affected by exogenous changes and what determines their correlation. A main implication of the model is that differences in the amount of public subsidies to education and educational quality produce cross-country patterns with a negative correlation between inequality and mobility. Differences in the labor market, like differences in skill-biased technology or wage compression instead produce a positive correlation. The predictions of the model are found to be consistent with various empirical observations on mobility and inequality.
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