Takamasa Yamagami

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Preprint submitted to Elsevier 4 September 2008 We have observed cosmic-ray electrons from 10 GeV to 800 GeV by a long duration balloon flight using Polar Patrol Balloon (PPB) in Antarctica. The observation was carried out for 13 days at an average altitude of 35 km in January 2004. The detector is an imaging calorimeter composed of scintillating-fiber(More)
BACKGROUND Hepatocellular carcinoma (HCC) commonly develops in patients with chronic hepatitis or cirrhosis of the liver caused by hepatitis-C-virus (HCV) infection. We prospectively studied whether irregular regeneration of hepatocytes is a risk factor for HCC in these patients. METHODS 242 patients were enrolled after liver biopsy and followed up by(More)
In two long-duration balloon flights over Antarctica, the Balloon-borne Experiment with a Superconducting Spectrometer (BESS) collaboration has searched for antihelium in the cosmic radiation with the highest sensitivity reported. BESS-Polar I flew in 2004, observing for 8.5 days. BESS-Polar II flew in 2007-2008, observing for 24.5 days. No antihelium(More)
A Balloon-borne Superconducting Submillimeter-Wave Limb-Emission Sounder (BSMILES) to measure vertical profile of stratospheric minor constituents was developed. BSMILES carries a 300mm-diameter offset parabolic antenna, a 650-GHz heterodyne SIS receiver, and an acousto-optical spectrometer. The SIS junction chip consists of two Nb/A10x/Nb junctions(More)
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