We measure muon intensities at sea level by using the OKAYAMA cosmic-ray telescope in detail. Measured muons are also contained in the low-momentum region where they are strongly affected by geomagnetic field effects including the east-west effect. We report the zenith and azimuthal angular dependence of conventional muons in the momentum range 1.5-250 GeV/c in the zenith angular range 0 • -81 • . S Tsuji et al

The Large Area Air Shower (LAAS) group has been performing a network observation of extensive air showers (EAS) since 1996 in Japan. Eight compact EAS arrays (ten in the near future) are operating simultaneously and independently at distant stations (up to ≈ 1000 km), constituting a gigantic detector system as a whole. Using five stations' datasets, large-scale coincidences of EAS have been searched for with the aim of detecting signals from extremely short bursts in the universe. By comparing arrival times and arrival directions of all registered EAS, three coincident and parallel EAS pairs were extracted out of a sea of background cosmic rays. One of them was observed almost from the direction of the Crab Nebula, a previously reported ultra-high-energy γ-ray source. The first application reported here allows the analysis techniques to be tested and demonstrates the potential of observations with the full operation of the network detector system.

Extensive air showers (EASs) originated from primary cosmic ray energies above 10¹⁵ eV have been measured at multiple EAS observatories deployed in Japan since Sept. 1996. The typical EAS array has been located at the rooftop of the buildings in the university campus, and has GPS-disciplined 10 MHz oscillator to provide the UTC time stamp for each EAS event within a few μs accuracies. Searching for simultaneous and parallel EAS events at multiple EAS observatories due to Gerasimova-Zatsepin (GZ) effects have been carried out by comparing EAS arrival time stamps and directions detected by several baseline combinations of EAS arrays. <br><br> The EAS pairs whose time difference and angular distance were less than 5 ms and less than 15&deg; respectively, were selected and their angular distances from the solar direction and the lunar direction were examined. The data were compared with numerical GZ probability as a function of arrival directions of cosmic ray nuclei. Consequently, significant excesses of these events in the solar direction as expected in the numerical prediction of GZ effects were not found. We however found that the deficiencies of EAS pairs in the lunar direction, but its deviation is not significant

Contrast-enhanced ultrasonography with Sonazoid™ is a highly sensitive and specific method for the diagnosis of bowel ischemia.

No abstract