2,962 research outputs found

    The Shadow Economy and Morals: A Note

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    If the established rules are obeyed spontaneously in an economy, this increases economic efficiency since the uncertainties, monitoring costs and incentive problems induced by opportunism can be avoided. Opportunism will be increasedby increasing the incentives for unlawful behaviour, however, and a slight increase in these incentives might cause a cumulative and self-nourishing breakdown of morals. The dangers of the growing shadow economy are louring here

    A survey of backward proton and pion production in p+C interactions at beam momenta from 1 to 400 GeV/c

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    New data on proton and pion production in p+C interactions from the CERN PS and SPS accelerators are used in conjunction with other available data sets to perform a comprehensive survey of backward hadronic cross sections. This survey covers the complete backward hemisphere in the range of lab angles from 10 to 180 degrees, from 0.2 to 1.4 GeV/c in lab momentum and from 1 to 400 GeV/c in projectile momentum. Using the constraints of continuity and smoothness of the angular, momentum and energy dependences a consistent description of the inclusive cross sections is established which allows the control of the internal consistency of the nineteen available data sets.Comment: 52 pages 47 figure

    Intercontinental transport of nitrogen oxide pollution plumes

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    We describe the first satellite observation of intercontinental transport of nitrogen oxides emitted by power plants, verified by simulations with a particle tracer model. The analysis of such episodes shows that anthropogenic NO<sub>x</sub> plumes may influence the atmospheric chemistry thousands of kilometers away from its origin, as well as the ocean they traverse due to nitrogen fertilization. This kind of monitoring became possible by applying an improved algorithm to extract the tropospheric fraction of NO<sub>2</sub> from the spectral data coming from the GOME instrument.<br> <br> As an example we show the observation of NO<sub>2</sub> in the time period 4--14 May, 1998, from the South African Plateau to Australia which was possible due to favourable weather conditions during that time period which availed the satellite measurement. This episode was also simulated with the Lagrangian particle dispersion model FLEXPART which uses NO<sub>x</sub> emissions taken from an inventory for industrial emissions in South Africa and is driven with analyses from the European Centre for Medium-Range Weather Forecasts. Additionally lightning emissions were taken into account by utilizing Lightning Imaging Sensor data. Lightning was found to contribute probably not more than 25% of the resulting concentrations. Both, the measured and simulated emission plume show matching patterns while traversing the Indian Ocean to Australia and show great resemblance to the aerosol and CO<sub>2</sub> transport observed by Piketh et al. (2000)

    A case of open angle glaucoma secondary to Posner-Schlossman Syndrome

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    This is a case report demonstrating appropriate diagnosis and management of PSS and its possible sequelae. Posner-Schlossman Syndrome is characterized by recurrent, unilateral attacks of significantly increased intraocular pressure. The etiology and pathophysiology of this condition remains unclear. Duration of this chronic condition and the risk of developing secondary open angle glaucoma are directly proportional. The patient and managing optometrist must be aware of the necessity of timely intervention during acute attacks, as well as adherent longitudinal care to preserve function and quality of life. The ensuing case report and review underscores the impact of this disease

    OpenFluor- an online spectral library of auto-fluorescence by organic compounds in the environment

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    An online repository of published organic fluorescence spectra has been developed, which can be searched for quantitative matches with any set of unknown spectra. It fills a critical gap by increasing access to measured and modelled (PARAFAC) spectra, and linking across studies and systems to reveal "global" fluorescence trends

    Microscopic calculations of stopping and flow from 160AMeV to 160AGeV

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    The behavior of hadronic matter at high baryon densities is studied within Ultrarelativistic Quantum Molecular Dynamics (URQMD). Baryonic stopping is observed for Au+Au collisions from SIS up to SPS energies. The excitation function of flow shows strong sensitivities to the underlying equation of state (EOS), allowing for systematic studies of the EOS. Effects of a density dependent pole of the ρ\rho-meson propagator on dilepton spectra are studied for different systems and centralities at CERN energies.Comment: Proceedings of the Quark Matter '96 Conference, Heidelberg, German

    Development of a custom OMI NO2 data product for evaluating biases in a regional chemistry transport model

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    In this paper, we present the custom Hong Kong NO2 retrieval (HKOMI) for the Ozone Monitoring Instrument (OMI) on board the Aura satellite which was used to evaluate a high-resolution chemistry transport model (CTM) (3 km x 3 km spatial resolution). The atmospheric chemistry transport was modelled in the Pearl River Delta (PRD) region in southern China by the Models-3 Community Multiscale Air Quality (CMAQ) modelling system from October 2006 to January 2007. In the HKOMI NO2 retrieval, tropospheric air mass factors (AMFs) were recalculated using high-resolution ancillary parameters of surface reflectance, a priori NO2 and aerosol profiles, of which the latter two were taken from the CMAQ simulation. We tested the influence of the ancillary parameters on the data product using four different aerosol parametrizations. Ground-level measurements by the PRD Regional Air Quality Monitoring (RAQM) network were used as additional independent measurements. The HKOMI retrieval increases estimated tropospheric NO2 vertical column densities (VCD) by (+31 +/- 38) %,when compared to NASA's standard product (OMNO2-SP),and improves the normalized mean bias (NMB) between satellite and ground observations by 26 percentage points from -41 to -15 %. The individual influences of the parameters are (+11.4 +/- 13.4)% for NO2 profiles,(+11.0 +/- 20.9)% for surface reflectance and (+6.0 +/- 8.4)% for the best aerosol parametrization. The correlation coefficient r is low between ground and satellite observations (r = 0.35). The low r and the remaining NMB can be explained by the low model performance and the expected differences when comparing point measurements with area-averaged satellite observations. The correlation between CMAQ and the RAQM network is low (r approximate to 0.3) and the model underestimates the NO2 concentrations in the northwestern model domain (Foshan and Guangzhou). We compared the CMAQ NO2 time series of the two main plumes with our best OMI NO2 data set (HKOMI-4). The model overestimates the NO2 VCDs by about 15% in Hong Kong and Shenzhen, while the correlation coefficient is satisfactory (r = 0.56). In Foshan and Guangzhou, the correlation is low (r = 0.37) and the model underestimates the VCDs strongly (NMB = -40 %). In addition, we estimated that the OMI VCDs are also underestimated by about 10 to 20% in Foshan and Guangzhou because of the influence of the model parameters on the AMFs. In this study, we demonstrate that the HKOMI NO2 retrieval reduces the bias of the satellite observations and how the data set can be used to study the magnitude of NO2 concentrations in a regional model at high spatial resolution of 3 x 3 km(2). The low bias was achieved with recalculated AMFs using updated surface reflectance, aerosol profiles and NO2 profiles. Since unbiased concentrations are important, for example, in air pollution studies, the results of this paper can be very helpful in future model evaluation studies

    Un cas de glaucome à angle ouvert consécutif au syndrome de Posner-Schlossman

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    Cette observation clinique présente le diagnostic et la prise en charge appropriés du syndrome de Posner-Schlossman (SPS) et de ses séquelles possibles. Le SPS se caractérise par des poussées unilatérales et récurrentes de pression intraoculaire fortement accrue. Bien que l’étiologie et la pathophysiologie de cette maladie chronique demeurent incertaines, sa durée est directement corrélée au risque de développer un glaucome secondaire à angle ouvert. Le patient et l’optométriste responsable doivent être conscients de la nécessité d’une intervention en temps opportun pendant les poussées aiguës, ainsi que du respect des soins longitudinaux pour préserver la fonction et la qualité de vie. Cette observation clinique et cet examen de cas soulignent l’impact de cette maladie

    Salivary acinic cell carcinoma: reappraisal and update

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    Epidemiologic and clinicopathologic features, therapeutic strategies, and prognosis for acinic cell carcinoma of the major and minor salivary glands are critically reviewed. We explore histopathologic, histochemical, electron microscopic and immunohistochemical aspects and discuss histologic grading, histogenesis, animal models, and genetic events. In the context of possible diagnostic difficulties, the relationship to mammary analog secretory carcinoma is probed and a classification is suggested. Areas of controversy or uncertainty, which may benefit from further investigations, are also highlighted
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