34 research outputs found

    A Great Space Weather Event in February 1730

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    Aims. Historical records provide evidence of extreme magnetic storms with equatorward auroral extensions before the epoch of systematic magnetic observations. One significant magnetic storm occurred on February 15, 1730. We scale this magnetic storm with auroral extension and contextualise it based on contemporary solar activity. Methods. We examined historical records in East Asia and computed the magnetic latitude (MLAT) of observational sites to scale magnetic storms. We also compared them with auroral records in Southern Europe. We examined contemporary sunspot observations to reconstruct detailed solar activity between 1729 and 1731. Results. We show 29 auroral records in East Asian historical documents and 37 sunspot observations. Conclusions. These records show that the auroral displays were visible at least down to 25.8{\deg} MLAT throughout East Asia. In comparison with contemporary European records, we show that the boundary of the auroral display closest to the equator surpassed 45.1{\deg} MLAT and possibly came down to 31.5{\deg} MLAT in its maximum phase, with considerable brightness. Contemporary sunspot records show an active phase in the first half of 1730 during the declining phase of the solar cycle. This magnetic storm was at least as intense as the magnetic storm in 1989, but less intense than the Carrington event.Comment: 30 pages, 5 figures, and 2 tables, accepted for publication in Astronomy & Astrophysics on 25 April 2018. The figures and transcriptions/translations of historical documents are partially omitted in this manuscript due to the condition of reproduction. They are available in the publisher versio

    Complication of portal vein thrombosis after right hemihepatectomy in a patient lacking the portal vein bifurcation

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    Absence of portal vein bifurcation is a rare anomaly. We report a patient with this anomaly who underwent right hemihepatectomy for treatment of hepatocellular carcinoma. Although the procedure was carefully performed with a preoperative three-dimensional simulation and intraoperative cholangiography, postoperative portal vein thrombosis occurred

    Atypically large well-differentiated hepatocellular carcinoma with extensive fatty metamorphosis : Report of a Case

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    A large well-differentiated hepatocellular carcinoma (HCC) with fatty change is rare, and to date only a few cases have been reported. Herein, we present a 68-year-old man who developed a well-differentiated HCC with extensive fatty metamorphosis. The patient was referred to our institute because of a rapidly growing tumor in the left lobe of the liver. Ultrasonography showed a hyperechoic lesion with a peripheral hypoechoic area. Dynamic contrast-enhanced computed tomography (CT) scan in all three phases revealed the tumor which showed diffuse low attenuation with internal irregular enhancement. He underwent left lateral segmentectomy at the liver. Histological diagnosis confirmed well-differentiated HCC and the surrounding non-cancerous area was diagnosed as non-alcoholic steatohepatitis. The patient is still alive without recurrence after 17 months of follow-up
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