957 research outputs found

    Assessing poverty and inequality at a detailed regional level: New advances in spatial microsimulation

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    During the past three years NATSEM has developed pathbreaking spatial microsimulation techniques, involving the creation of synthetic data about the socioeconomic characteristics of households at a detailed regional level. The data are potentially available at any level of geographic aggregation, down to the level of the Census Collection District (about 200 households). This paper describes the results of initial attempts to link the new database to NATSEM’s existing STINMOD static microsimulation model of taxes and transfers in Australia, so that the spatial impact upon poverty and inequality of possible policy changes can be assessed. This paper outlines the new techniques used to create the synthetic household microdata and demonstrates how they can be used to analyse poverty rates, the spatial impact of possible policy change, and the characteristics of the poor by geographic area. – poverty ; inequality ; measurement ; Australi

    Compton Scattering in Ultra-Strong Magnetic Fields: Numerical and Analytical Behavior in the Relativistic Regime

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    This paper explores the effects of strong magnetic fields on the Compton scattering of relativistic electrons. Recent studies of upscattering and energy loss by relativistic electrons that have used the non-relativistic, magnetic Thomson cross section for resonant scattering or the Klein-Nishina cross section for non-resonant scattering do not account for the relativistic quantum effects of strong fields (>4×1012 > 4 \times 10^{12} G). We have derived a simplified expression for the exact QED scattering cross section for the broadly-applicable case where relativistic electrons move along the magnetic field. To facilitate applications to astrophysical models, we have also developed compact approximate expressions for both the differential and total polarization-dependent cross sections, with the latter representing well the exact total QED cross section even at the high fields believed to be present in environments near the stellar surfaces of Soft Gamma-Ray Repeaters and Anomalous X-Ray Pulsars. We find that strong magnetic fields significantly lower the Compton scattering cross section below and at the resonance, when the incident photon energy exceeds mec2m_ec^2 in the electron rest frame. The cross section is strongly dependent on the polarization of the final scattered photon. Below the cyclotron fundamental, mostly photons of perpendicular polarization are produced in scatterings, a situation that also arises above this resonance for sub-critical fields. However, an interesting discovery is that for super-critical fields, a preponderance of photons of parallel polarization results from scatterings above the cyclotron fundamental. This characteristic is both a relativistic and magnetic effect not present in the Thomson or Klein-Nishina limits.Comment: AASTeX format, 31 pages included 7 embedded figures, accepted for publication in The Astrophysical Journa

    Compton Scattering in Ultra-Strong Magnetic Fields: Numerical and Analytical Behavior in the Relativistic Regime

    Get PDF
    This paper explores the effects of strong magnetic fields on the Compton scattering of relativistic electrons. Recent studies of upscattering and energy loss by relativistic electrons that have used the non-relativistic, magnetic Thomson cross section for resonant scattering or the Klein-Nishina cross section for non-resonant scattering do not account for the relativistic quantum effects of strong fields (>4×1012 > 4 \times 10^{12} G). We have derived a simplified expression for the exact QED scattering cross section for the broadly-applicable case where relativistic electrons move along the magnetic field. To facilitate applications to astrophysical models, we have also developed compact approximate expressions for both the differential and total polarization-dependent cross sections, with the latter representing well the exact total QED cross section even at the high fields believed to be present in environments near the stellar surfaces of Soft Gamma-Ray Repeaters and Anomalous X-Ray Pulsars. We find that strong magnetic fields significantly lower the Compton scattering cross section below and at the resonance, when the incident photon energy exceeds mec2m_ec^2 in the electron rest frame. The cross section is strongly dependent on the polarization of the final scattered photon. Below the cyclotron fundamental, mostly photons of perpendicular polarization are produced in scatterings, a situation that also arises above this resonance for sub-critical fields. However, an interesting discovery is that for super-critical fields, a preponderance of photons of parallel polarization results from scatterings above the cyclotron fundamental. This characteristic is both a relativistic and magnetic effect not present in the Thomson or Klein-Nishina limits.Comment: AASTeX format, 31 pages included 7 embedded figures, accepted for publication in The Astrophysical Journa

    Research Paper No. 2004/26 Assessing Poverty and Inequality at a Detailed Regional Level New Advances in Spatial Microsimulation

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    During the past three years NATSEM has developed pathbreaking spatial microsimulation techniques, involving the creation of synthetic data about the socioeconomic characteristics of households at a detailed regional level. The data are potentially available at any level of geographic aggregation, down to the level of the Census Collection District (about 200 households). This paper describes the results of initial attempts to link the new database to NATSEM’s existing STINMOD static microsimulation model of taxes and transfers in Australia, so that the spatial impact upon poverty and inequality of possible policy changes can be assessed. This paper outlines the new techniques used to create the synthetic household microdata and demonstrates how they can be used to analyse poverty rates, the spatial impact of possible policy change, and the characteristics of the poor by geographic area

    The early Quaternary North Sea Basin

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    The onset of the Quaternary (2.58 Ma) corresponds to significant paleo-environmental events, such as the intensification and southward extension of Northern Hemisphere glaciation. In the North Sea Basin a significant late Cenozoic succession has been identified as a high-resolution archive of paleo-environmental changes during the Pliocene and Pleistocene. However, the identification of the base of the Quaternary has been a long-standing issue owing to lack of stratigraphic calibration. This study incorporates continuous, regional 3D seismic data with high-quality chronostratigraphic markers to map the base-Quaternary surface at high resolution across the entire North Sea. Depth conversion, backstripping, seismic geomorphology and sedimentation rate calculations are integrated to analyse the paleogeographical evolution of the North Sea Basin and its infill of c. 83 × 103 km3 of northward prograding marine to deltaic sediments. The basin is 600 km long from SSE to NNW and largely localized above residual topography of the Mesozoic graben system. During the earliest Quaternary (2.58 – 2.35 Ma) paleo-water depths were c. 300 ± 50 m and solid sedimentation rates (calculated from 0% porosity) c. 32 km3 ka−1. The base-Quaternary provides an important marker for further studies of the changing environment of the Quaternary of NW Europe as well as resource and shallow geohazard analysis. Supplementary material: A base Quaternary two-way travel time structure map is available at https://doi.org/10.6084/m9.figshare.c.390034

    Medically relevant Acinetobacter species require a type II secretion system and specific membrane-associated chaperones for the export of multiple substrates and full virulence

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    Acinetobacter baumannii, A. nosocomialis, and A. pittii have recently emerged as opportunistic human pathogens capable of causing severe human disease; however, the molecular mechanisms employed by Acinetobacter to cause disease remain poorly understood. Many pathogenic members of the genus Acinetobacter contain genes predicted to encode proteins required for the biogenesis of a type II secretion system (T2SS), which have been shown to mediate virulence in many Gram-negative organisms. Here we demonstrate that Acinetobacter nosocomialis strain M2 produces a functional T2SS, which is required for full virulence in both the Galleria mellonella and murine pulmonary infection models. Importantly, this is the first bona fide secretion system shown to be required for virulence in Acinetobacter. Using bioinformatics, proteomics, and mutational analyses, we show that Acinetobacter employs its T2SS to export multiple substrates, including the lipases LipA and LipH as well as the protease CpaA. Furthermore, the Acinetobacter T2SS, which is found scattered amongst five distinct loci, does not contain a dedicated pseudopilin peptidase, but instead relies on the type IV prepilin peptidase, reinforcing the common ancestry of these two systems. Lastly, two of the three secreted proteins characterized in this study require specific chaperones for secretion. These chaperones contain an N-terminal transmembrane domain, are encoded adjacently to their cognate effector, and their disruption abolishes type II secretion of their cognate effector. Bioinformatic analysis identified putative chaperones located adjacent to multiple previously known type II effectors from several Gram-negative bacteria, which suggests that T2SS chaperones constitute a separate class of membrane-associated chaperones mediating type II secretion

    Repurposing web analytics to support the IoT

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    Internet of Things analytics engines are complex to use and often optimized for a single domain or limited to proprietary data. A prototype system shows that existing Web analytics technologies can successfully be repurposed for IoT applications including sensor monitoring and user engagement tracking
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