812 research outputs found

    Radio propagation measurements and modeling for standardization of the site general path loss model in International Telecommunications Union recommendations for 5G wireless networks

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    The International Telecommunications Union Radiocommunication Sector (ITU‐R) Study Group 3 identified the need for a number of radio channel models in anticipation of the World Radiocommunications Conference in 2019 when the frequency allocation for 5G will be discussed. In response to the call for propagation path loss models, members of the study group carried out measurements in the frequency bands between 0.8 GHz up to 73 GHz in urban low rise and urban high rise as well as suburban environments. The data were subsequently merged to generate site general path loss models. The paper presents an overview of the radio channel measurements, the measured environments, the data analysis and the approach for the derivation of the path loss model adopted in Recommendation ITU‐R P.1411‐10

    A CO funnel in the Galactic centre: molecular counterpart of the northern Galactic chimney

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    We report the discovery of a velocity coherent, funnel-shaped 13CO emission feature in the Galactic centre (GC) using data from the SEDIGISM survey. The molecular cloud appears as a low-velocity structure (VLSR = [ − 3.5, + 3.5] km s−1) with an angular extent of 0.95° ×1°, extending towards positive Galactic latitudes. The structure is offset from Sgr A* towards negative Galactic longitudes; it spatially and morphologically correlates well with the northern lobe of the 430 pc radio bubble, believed to be the radio counterpart of the multiwavelength GC chimney. Spectral line observations in the frequency range of 85–116 GHz have been carried out using the IRAM 30-m telescope towards 12 positions along the funnel-shaped emission. We examine the 12C/13C isotopic ratios using various molecules and their isotopologues. The mean 12C/13C isotope ratio (30.6 ± 2.9) is consistent with the structure located within inner 3 kpc of the Galaxy and possibly in the GC. The velocity of the molecular funnel is consistent with previous radio recombination line measurements of the northern lobe of radio bubble. Our multiwavelength analysis suggests that the funnel-shaped structure extending over 100 pc above the Galactic plane is the molecular counterpart of the northern GC chimney

    A CO Funnel in the Galactic Centre: Molecular Counterpart of the Northern Galactic Chimney?

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    We report the discovery of a velocity coherent, funnel shaped ^13CO emission feature in the Galactic centre (GC) using data from the SEDIGISM survey. The molecular cloud appears as a low velocity structure (V_LSR=[-3.5, +3.5] km/s) with an angular extent of 0.95{\deg} x 1{\deg}, extending toward positive Galactic latitudes. The structure is offset from Sgr A* toward negative Galactic longitudes and spatially and morphologically correlates well with the northern lobe of the 430 pc radio bubble, believed to be the radio counterpart of the multiwavelength GC chimney. Spectral line observations in the frequency range of 85-116 GHz have been carried out using the IRAM 30 metre telescope toward 12 positions along the funnel-shaped emission. We examine the ^12C/^13C isotopic ratios using various molecules and their isotopologues. The mean ^12C/^13C isotope ratio (30.6+-2.9) is consistent with the structure located within inner 3 kpc of the Galaxy and possibly in the GC. The velocity of the molecular funnel is consistent with previous radio recombination line measurements of the northern lobe of radio bubble. Our multiwavelength analysis suggests that the funnel shaped structure extending over 100 pc above the Galactic plane is the molecular counterpart of the northern GC chimney.Comment: Accepted for publication in A&A Letter

    Image-Aligned Dynamic Liver Reconstruction Using Intra-Operative Field of Views for Minimal Invasive Surgery

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    Available online on 30 November 2018. Author's post-print on open access repository after an embargo period of 12 months2019-11-3

    An occasional diagnosis of myasthenia gravis - a focus on thymus during cardiac surgery: a case report

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    <p>Abstract</p> <p>Background</p> <p>Myasthenia gravis, an uncommon autoimmune syndrome, is commonly associated with thymus abnormalities. Thymomatous myasthenia gravis is considered to have worst prognosis and thymectomy can reverse symptoms if precociously performed.</p> <p>Case report</p> <p>We describe a case of a patient who underwent mitral valve repair and was found to have an occasional thymomatous mass during the surgery. A total thymectomy was performed concomitantly to the mitral valve repair.</p> <p>Conclusion</p> <p>The diagnosis of thymomatous myasthenia gravis was confirmed postoperatively. Following the surgery this patient was strictly monitored and at 1-year follow-up a complete stable remission had been successfully achieved.</p

    OFF-eNET: An optimally fused fully end-to-end network for automatic dense volumetric 3D intracranial blood vessels segmentation

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    Intracranial blood vessels segmentation from computed tomography angiography (CTA) volumes is a promising biomarker for diagnosis and therapeutic treatment in cerebrovascular diseases. These segmentation outputs are a fundamental requirement in the development of automated decision support systems for preoperative assessment or intraoperative guidance in neuropathology. The state-of-the-art in medical image segmentation methods are reliant on deep learning architectures based on convolutional neural networks. However, despite their popularity, there is a research gap in the current deep learning architectures optimized to address the technical challenges in blood vessel segmentation. These challenges include: (i) the extraction of concrete brain vessels close to the skull; and (ii) the precise marking of the vessel locations. We propose an Optimally Fused Fully end-to-end Network (OFF-eNET) for automatic segmentation of the volumetric 3D intracranial vascular structures. OFF-eNET comprises of three modules. In the first module, we exploit the up-skip connections to enhance information flow, and dilated convolution for detailed preservation of spatial feature map that are designed for thin blood vessels. In the second module, we employ residual mapping along with inception module for speedy network convergence and richer visual representation. For the third module, we make use of the transferred knowledge in the form of cascaded training strategy to gradually optimize the three segmentation stages (basic, complete, and enhanced) to segment thin vessels located close to the skull. All these modules are designed to be computationally efficient. Our OFF-eNET, evaluated using 70 CTA image volumes, resulted in 90.75% performance in the segmentation of intracranial blood vessels and outperformed the state-of-the-art counterparts
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