684 research outputs found

    Physical and optical properties of atmospheric aerosols by in-situ and radiometric measurements

    Get PDF
    Physical and optical properties of atmospheric aerosols collected by using a high resolution (1.5 nm) spectroradiometer (spectral range 400–800 nm), a 13-stage Dekati Low Pressure Impactor (size range 30 nm–10 μm), and an AE31 Aethalometer (7 wavelenghts from 370 nm to 950 nm), have been examined in a semi-rural site in Southwest Italy (Tito Scalo, 40°35' N, 15°41' E, 750 m a.s.l.). In particular, daily averaged values of AOD and Ångström turbidity parameters from radiometric data together with mass-size distributions from impactor data and Black Carbon (BC) concentrations have been analyzed from May to October 2008. Furthermore, by inverting direct solar radiances, aerosol columnar number and volume size distributions have been obtained for the same period. The comparison of different observation methods, allowed to verify if, and in what conditions, changes in aerosol properties measured at ground are representative of columnar properties variations. Agreement between columnar and in-situ measurements has been obtained in case of anthropogenic aerosol loading, while in case of Saharan dust intrusions some discrepancies have been found when dust particles were located at high layers in the atmosphere (4–8 km) thus affecting columnar properties more than surface ones. For anthropogenic aerosols, a good correlation has been confirmed through the comparison of fine aerosol fraction contribution as measured by radiometer, impactor and aethalometer, suggesting that, in this case, the particles are more homogeneously distributed over the lower layers of atmosphere and columnar aerosol optical properties are dominated by surface measured component

    Rare histotype of sporadic Creutzfeldt-Jakob disease, clinically suspected as corticobasal degeneration

    Get PDF
    Sporadic Creutzfeldt-Jakob disease (sCJD) is a rare neurodegenerative disease that can mimic other neurological disorders. We present a case of sCJD in a 64-year-old man that presented with corticobasal syndrome and survived for 3 years. He presented initially with dementia, hemiparkinsonism and alien limb phenomenon and was diagnosed with corticobasal degeneration, ultimately progressing to immobility and akinetic mutism. With a normal MRI 1 year before onset, his neuroimaging 1 year later revealed abnormal DaTscan, cortical and hippocampal atrophy with ventricular dilatation on MRI, and diffusion-weighted cortical ribboning and thalamic hyperintensity. Postmortem, the patient’s brain was collected by the Parkinson’s UK Tissue Bank. Prion protein immunohistochemistry revealed widespread diffuse microvacuolar staining without kuru-type plaques. Hyperphosphorylated tau was only found in the entorhinal cortex and hippocampus. This case highlights the clinical heterogeneity of sCJD presentation and the important inclusion of CJD in the differential diagnosis of atypical presentations of neurodegenerative disease

    Tools for Quality Testing of Batches of Artifacts: The Cryogenic Thermometers for the LHC

    Get PDF
    In the processing of data series, such as in the case of the resistance R vs. temperature T calibrations of the thermometers (several thousands) necessary for the LHC new accelerator at CERN, it is necessary to use automatic methods for determining the quality of the acquired data and the degree of uniformity of the thermometer characteristics, that are of the semiconducting type. In addition, it must be determined if the calibration uncertainties comply with the specifications in the wide temperature range 1,6 - 300 K. Advantage has been taken of the fact that these thermometers represent a population with limited variability, to apply a Least Squares Method with Fixed Effect. This allows to fit the data of all the thermometers together, by taking into account the individuality of each thermometer in the model as a deviation from one of them taken as reference Ri = f(Ti) + bk0 + bk1 g(Tki) + bk1g(Tki)2 + ... where f(Ti) is the model valid for all i data and all k thermometers, while the subsequent part is the "fixed effect" model for the k-th thermometer, where g(T) is a suitable function of T. This method is shown in the paper applied to different stages of the data processing. First, for efficient compensation for the thermal drift occurring during acquisition, robust against the occurrence of outliers. Second, for detection of clusters of thermometers with inherently different characteristics. Finally, for optimisation of the calibration-point distribution

    Cryogenic Thermometer Calibration Facility at CERN

    Get PDF
    A cryogenic thermometer calibration facility has been designed and is being commissioned in preparation for the very stringent requirements on the temperature control of the LHC superconducting magnets. The temperature is traceable in the 1.5 to 30 K range to standards maintained in a national metrological laboratory by using a set of Rhodium-Iron temperature sensors of metrological quality. The calibration facility is designed for calibrating simultaneously 60 industrial cryogenic thermometers in the 1.5 K to 300 K temperature range, a thermometer being a device that includes both a temperature sensor and the wires heat-intercept. The thermometers can be calibrated in good and degraded vacuum or immersed in the surrounding fluid and at different Joule self-heating conditions that match those imposed by signal conditioners used in large cryogenic machinery. The calibration facility can be operated in an automatic mode and all the control and safety routines are handled by a Programmable Logic Controller (PLC). LabVIEW is used both as the PLC operator interface and for configuring and reading the thermometric data sampled by the higher accuracy laboratory equipment. The isothermal support onto which the thermometers are mounted is thermally anchored through the wiring to a helium bath. The calibration procedure begins once the temperature of the support is stabilized. Measured data is presented and it is possible to infer that the absolute accuracy that can be obtained is better than ± 5 mK for the full temperature range

    MSWI Fly Ash Multiple Washing: Kinetics of Dissolution in Water, as Function of Time, Temperature and Dilution

    Get PDF
    Municipal solid waste incineration fly ash (FA) can represent a sustainable supply of supplementary material to the construction industries if it is pre-treated to remove hazardous substances such as chloride, sulfate, and heavy metals. In this paper, the phenomenology associated with a water washing multi-cycle treatment of FA is investigated, focusing attention upon the mineral dissolution process. The efficacy of the treatment is assessed by leaching tests, according to the European Standard, and discussed in light of the occurring mineral phases. The water-to-solid (L/S) ratio is a crucial parameter, along with the number of washing cycles, for removing halite and sylvite, whereas quartz, calcite, anhydrite, and an amorphous phase remain in the solid residue. The sequential extraction method and dissolution kinetics modelling provide further elements to interpret leaching processes, and suggest that dissolution takes place through a two-step mechanism. Altogether, multi-step washing with L/S = 5 is effective in reducing contaminants under the legal limits for non-hazardous waste disposal, while the legal limits for non-reactive or reusable material cannot be completely reached, owing to sulfate and some heavy metals which still leached out from the residue

    Opicapone in UK clinical practice: effectiveness, safety and cost analysis in patients with Parkinson's disease.

    Get PDF
    Aim: This subanalysis of the OPTIPARK study aimed to confirm the effectiveness and safety of opicapone in patients with Parkinson's disease and motor fluctuations in clinical practice specifically in the UK and to assess the impact of opicapone on treatment costs. Methods: Patients received opicapone added to levodopa for 6 months. Clinical outcomes were assessed at 3 and 6 months and treatment costs at 6 months. Results: Most patients' general condition improved at 3 months, with sustained improvements reported at 6 months. Opicapone improved motor and non-motor symptoms at both timepoints, was generally well tolerated and reduced total treatment costs by GBP 3719. Conclusion: Opicapone added to levodopa resulted in clinical improvements and reduced treatment costs across UK clinical practice

    LAPW frozen-phonon calculation, shell model lattice dynamics and specific-heat measurement of SnO

    Full text link
    An ab-initio Linear Augmented Plane-Wave (LAPW) calculation of the zone-centered phonon frequencies of SnO has been performed. Eg_g symmetry has been ascribed to the mode observed at 113 cm−1^{-1} in Raman measurements, discarding a previous B1g_{1g} assignement. The other phonon modes measured by Raman spectroscopy are also well reproduced. A new shell-model has also been developed, that gives good agreement of the zone-centered frequencies compared to the measured data and the LAPW results. Specific heat measurements have been performed between 5 K and 110 K. Computation of the specific heat and the M\"{o}ssbauer recoilless fraction with the improved shell-model shows a good agreement with the experimental data as a function of temperature.Comment: 11 pages, 1 figure. to appear in Phys. Rev. B (November 1999
    • …
    corecore