149 research outputs found

    Fire emission heights in the climate system - Part 1: Global plume height patterns simulated by ECHAM6-HAM2

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    We use the global circulation model ECHAM6 extended by the aerosol module HAM2 to simulate global patterns in wildfire emission heights. Prescribed plume heights in ECHAM6 are replaced by an implementation of a simple, semi-empirical plume height parametrization. In a first step, the global performance of the plume height parametrization is evaluated for plumes reported in the Multiangle Imaging Spectroradiometer (MISR) Plume Height Project (MPHP) data set. Our results show that the parametrization simulates a largely reasonable global distribution of plume heights. While the modeled global mean plume height (1411 ± 646 m) is in good agreement with the observed mean (1382 ± 702 m), the upper and lower tails of the plume height distribution tend to be slightly underrepresented. Furthermore, we compare plume heights simulated by the simple parametrization to a more complex, analytical plume model. Major differences in global plume height distributions are found for the lowest 1.5 km, but reasonable agreement is observed for higher plumes. In a second step, fire radiative power (FRP) as reported in the global fire assimilation system (GFAS) is used to simulate plume heights for observed fires globally for the period 2005–2011. The global fraction of simulated daytime plumes injecting emissions into the free troposphere (FT) ranges from 3.7 ± 0.7 to 5.2 ± 1.0 %. This range is comparable to results from observational studies, but it is much lower than results for prescribed plume heights in the ECHAM6-HAM2 standard setup. Nevertheless, occasionally deep emission injections exceeding 5–7 km in height are simulated for intense fires and favorable meteorological conditions. The application of a prescribed diurnal cycle in FRP turns out to be of minor importance. For a hypothetical doubling in FRP, moderate changes in plume heights of 100–400 m are simulated. These small changes indicate that a potential future increase in fire intensity will only slightly impact the emission heights on a global scale

    Unilateral progressive osseous heteroplasia

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    A 50-year-old male patient presented with firm subcutaneous nodules and plaques with a gritty texture, unilaterally affecting the left side of the trunk and the left limbs. These lesions had had a progressive course since early childhood and caused functional impairment. There was no family history of similar disorders. No phospho-calcium metabolism abnormalities were observed. Biopsies of the affected areas demonstrated osteoma cutis. Analysis of DNA showed no mutation of the GNAS gene. The clinical features were consistent with progressive osseous heteroplasia, atypically presented in a unilateral form, probably revealing a mosaic distribution

    High-temperature superconducting fault current microlimiters

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    High-temperature superconducting microbridges implemented with YBa(2)Cu(3)O(7-delta) thin-films are shown to be possible fault current limiters for microelectronic devices with some elements working at temperatures below the superconducting critical temperature and, simultaneously, under very low power conditions (below 1W). This is the case in the important applications of superconductors as SQUID based electronics, and technologies for communication or infrared detectors. In this paper it is shown that the good thermal behavior of these microlimiters allows working in a regime where even relatively small faults induce their transition to highly dissipative states, dramatically increasing their limitation efficiency. The conditions for optimal refrigeration and operation of these microlimiters are also proposed.Comment: 10 pages, 3 figures. LaTeX and EPS file

    The structure of intercalated water in superconducting Na0.35_{0.35}CoO2â‹…_{2}\cdot1.37D2_{2}O: Implications for the superconducting phase diagram

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    We have used electron and neutron powder diffraction to elucidate the structural properties of superconducting \NaD. Our measurements show that our superconducting sample exhbits a number of supercells ranging from 1/3a∗{1/3}a^{*} to 1/15a∗{1/15}a^{*}, but the most predominant one, observed also in the neutron data, is a double hexagonal cell with dimensions \dhx. Rietveld analysis reveals that \deut\space is inserted between CoO2_{2} sheets as to form a layered network of NaO6_{6} triangular prisms. Our model removes the need to invoke a 5K superconducting point compound and suggests that a solid solution of Na is possible within a constant amount of water yy.Comment: 4 pages, 3 figure

    Differential Effects of Sodium and Magnesium Sulfate on Water Consumption by Beef Cattle

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    The existing guidelines for maximum sulfate (SO4) in cattle drinking water are based on Na2SO4, although many water sources contain greater concentrations of MgSO4. Two experiments compared the effect of different SO4 salts on water consumption and fecal DM of cattle. In Exp. 1, 8 yearling heifers (initial BW = 345 ± 8 kg; mean ± SD) were watered twice daily with tapwater or water containing Na2SO4 or MgSO4 at target levels of 1,500, 3,000, or 4,500 mg of SO4/L for 2-d treatment periods separated by 2 d of access to tapwater. In Exp. 2, 16 yearling cattle (initial BW = 421 ± 24 kg) were watered twice daily with tapwater (16 mg of SO4/L) or water containing Na2SO4 at target levels of 2,000 mg of SO4/L (low Na2SO4), MgSO4 at 2,000 mg of SO4/L (low MgSO4), or MgSO4 at 4,000 mg of SO4/L (high MgSO4) in 21-d treatment periods separated by 7-d periods on tapwater. The first 10 d of each period were allowed for adjustment to the treatment, and the final 11 d was considered the treatment period for analysis purposes. Treatments were applied in an incomplete Latin square, where each animal was exposed to 3 of the 4 treatments. In Exp. 1, the average daily water consumption decreased linearly as the SO4 concentration increased for MgSO4 (P = 0.0001) but not for Na2SO4 (P = 0.39). In Exp. 2, the average daily water consumption was less for cattle on the high-MgSO4 treatment than for cattle on the low-MgSO4 treatment (P = 0.0001), and cattle on the low-MgSO4 treatment tended (P = 0.09) to drink less than those on the tapwater treatment. Fecal DM was greater for cattle on the high-MgSO4 treatment than for those on the low-MgSO4 treatment (P \u3c 0.01). These findings indicate that cattle reduce their consumption of water containing high (≥ 4,000 mg of SO4/L) concentrations of MgSO4, even after a given time to adjust to the treatment; such reductions may be accompanied by an increase in fecal DM
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