51 research outputs found

    Propagation model for the Land Mobile Satellite channel in urban environments

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    This paper presents the major characteristics of a simulation package capable of performing a complete narrow and wideband analysis of the mobile satellite communication channel in urban environments for any given orbital configuration. The wavelength-to-average urban geometrical dimension ratio has required the use of the Geometrical Theory of Diffraction (GTD). For the RF frequency range, the model has been designed to be (1 up to 60 GHz) extended to include effects of non-perfect conductivity and surface roughness. Taking advantage of the inherent capabilities of such a high frequency method, we are able to provide a complete description of the electromagnetic field at the mobile terminal. Using the information made available at the ray-tracer and GTD solver outputs, the Land Mobile Satellite (LMS) urban model can also give a detailed description of the communication channel in terms of power delay profiles, Doppler spectra, channel scattering functions, and so forth. Statistical data, e.g. cumulative distribution functions, level crossing rates or distributions of fades are also provided. The user can access the simulation tool through a Design-CAD user-friendly interface by means of which she can effectively design her own urban layout and run consequently all the envisaged routines. The software is optimized in its execution time so that numerous runs can be achieved in a considerably short time

    Application of LANDSAT and Skylab data for land use mapping in Italy

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    Utilizing LANDSAT and Skylab multispectral imagery of 1972 and 1973, a land use map of the mountainous regions of Italy was evaluated at a scale of 1:250,000. Seven level I categories were identified by conventional methods of photointerpretation. Images of multispectral scanner (MSS) bands 5 and 7, or equivalents were mainly used. Areas of less than 200 by 200 m were classified and standard procedures were established for interpretation of multispectral satellite imagery. Land use maps were produced for central and southern Europe indicating that the existing land use maps could be updated and optimized. The complexity of European land use patterns, the intensive morphology of young mountain ranges, and time-cost calculations are the reasons that the applied conventional techniques are superior to automatic evaluation

    Application of LANDSAT data and digital image processing

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    There are no author-identified significant results in this report

    The First case of Locally Acquired Tick-Borne Babesia Microti

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    A child with a complicated medical history that included asplenia acquired an infection with Babesia microti in the summer of 2013 and had not travelled outside of Manitoba. Although the clinical findings were subtle, astute laboratory work helped to reach a preliminary identification of Babesia species, while reference laboratory testing confirmed the diagnosis. Blacklegged ticks (Ixodes scapularis) are known to transmit Borrelia burgdorferi and Anaplasma phagocytophilum in the province; however, the present case represents the first known instance of tick-borne B microti, both in Manitoba and in Canada. The expanding territory of the blacklegged tick increases the relevance of this emerging infection. Clinicians, laboratory medical practitioners and public health officials should be aware of B microti as a potential locally acquired infection in Canada

    Cystatin C: A Candidate Biomarker for Amyotrophic Lateral Sclerosis

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    Amyotrophic lateral sclerosis (ALS) is a fatal neurologic disease characterized by progressive motor neuron degeneration. Clinical disease management is hindered by both a lengthy diagnostic process and the absence of effective treatments. Reliable panels of diagnostic, surrogate, and prognostic biomarkers are needed to accelerate disease diagnosis and expedite drug development. The cysteine protease inhibitor cystatin C has recently gained interest as a candidate diagnostic biomarker for ALS, but further studies are required to fully characterize its biomarker utility. We used quantitative enzyme-linked immunosorbent assay (ELISA) to assess initial and longitudinal cerebrospinal fluid (CSF) and plasma cystatin C levels in 104 ALS patients and controls. Cystatin C levels in ALS patients were significantly elevated in plasma and reduced in CSF compared to healthy controls, but did not differ significantly from neurologic disease controls. In addition, the direction of longitudinal change in CSF cystatin C levels correlated to the rate of ALS disease progression, and initial CSF cystatin C levels were predictive of patient survival, suggesting that cystatin C may function as a surrogate marker of disease progression and survival. These data verify prior results for reduced cystatin C levels in the CSF of ALS patients, identify increased cystatin C levels in the plasma of ALS patients, and reveal correlations between CSF cystatin C levels to both ALS disease progression and patient survival

    Suprachoroidal hemorrhage. Clinical features and results of secondary surgical management

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    The purposes of this study are to identify clinical features in eyes with suprachoroidal hemorrhage which portend a poor visual prognosis and to determine visual outcome in these eyes after secondary surgical management of suprachoroidal hemorrhage. This was a retrospective study of 106 patients with suprachoroidal hemorrhages occurring in association with trauma (35), cataract surgery (30), glaucoma surgery (17), penetrating keratoplasty (6), corneal perforation (5), secondary lens implantation (3), pars plana vitrectomy (3), and other causes (7). Five (10%) of 49 eyes with a suprachoroidal hemorrhage and an initial retinal detachment had a visual outcome of 20/200 or better compared with 21 (43%) of 49 eyes without a retinal detachment. The presence or absence or a retinal detachment could not be determined in eight patients and all eight of these patients had a poor visual outcome. Sixteen (20%) of 82 eyes with a 360 degrees suprachoroidal hemorrhage had a visual outcome of 20/200 or better compared with 10 (47%) of 21 for those with suprachoroidal hemorrhage limited to one or two quadrants. The extent of the hemorrhage could not be determined in three eyes. Overall, 34% (14/41) of the patients with suprachoroidal hemorrhage who had a secondary surgical procedure achieved a visual outcome of 20/200 or better. Forty-three percent (6/14) who had a suprachoroidal hemorrhage during or after cataract surgery and who were treated with secondary surgical management achieved a visual outcome of 20/200 or greater. Clinical features associated with a poorer visual outcome included initial or indeterminate retinal detachment and 360 degrees suprachoroidal hemorrhage. Limited suprachoroidal hemorrhage without initial retinal detachment usually has a good visual prognosis and does not usually require secondary surgical intervention. However, if the former complication is present, secondary surgical intervention should be considered
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