36 research outputs found

    Availability analysis of a ship-to-ground FSO link

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    This paper analyzes the availability of a free-space optical (FSO) communication link, established between a maritime platform and a land base. In this analysis, the impact of the laser beam misalignment, caused by the vessel’s six oscillatory motions in a seaway, is considered. The hydrodynamic system is modeled, through a ship’s response amplitude operator (RAO), under a typical sea-state condition. Finally, the link availability is calculated based on FSO losses, considering a beam with Gaussian power distribution

    Human toxocariasis: contribution by Brazilian researchers

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    In the present paper the main aspects of the natural history of human infection by Toxocara larvae that occasionally result in the occurrence of visceral and/or ocular larva migrans syndrome were reviewed. The contribution by Brazilian researchers was emphasized, especially the staff of the Tropical Medicine Institute of SĂŁo Paulo (IMT)

    Comparability of automated drusen volume measurements in age-related macular degeneration: a MACUSTAR study report

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    Drusen are hallmarks of early and intermediate age-related macular degeneration (AMD) but their quantification remains a challenge. We compared automated drusen volume measurements between different OCT devices. We included 380 eyes from 200 individuals with bilateral intermediate (iAMD, n = 126), early (eAMD, n = 25) or no AMD (n = 49) from the MACUSTAR study. We assessed OCT scans from Cirrus (200 × 200 macular cube, 6 × 6 mm; Zeiss Meditec, CA) and Spectralis (20° × 20°, 25 B-scans; 30° × 25°, 241 B-scans; Heidelberg Engineering, Germany) devices. Sensitivity and specificity for drusen detection and differences between modalities were assessed with intra-class correlation coefficients (ICCs) and mean difference in a 5 mm diameter fovea-centered circle. Specificity was > 90% in the three modalities. In eAMD, we observed highest sensitivity in the denser Spectralis scan (68.1). The two different Spectralis modalities showed a significantly higher agreement in quantifying drusen volume in iAMD (ICC 0.993 [0.991–0.994]) than the dense Spectralis with Cirrus scan (ICC 0.807 [0.757–0.847]). Formulae for drusen volume conversion in iAMD between the two devices are provided. Automated drusen volume measures are not interchangeable between devices and softwares and need to be interpreted with the used imaging devices and software in mind. Accounting for systematic difference between methods increases comparability and conversion formulae are provided. Less dense scans did not affect drusen volume measurements in iAMD but decreased sensitivity for medium drusen in eAMD

    Labour market institutions, insider power and informal employment in Brazilian wage determination 1980-1993

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    SIGLEAvailable from British Library Document Supply Centre-DSC:DXN006301 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

    Currency substitution and indexed money

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    The paper tests the hypothesis that the presence of indexed money may rule out a process of currency substitution in contexts of persistent high inflation. Estimates for the case of Brazil using monthly data for the period 1985 to 1993 and cointegration techniques offer support for that
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