Influenza A viruses of different subtypes were isolated from fecal samples of ducks in their nesting areas in Siberia in summer from 1996 to 1998. Phylogenetic analysis of the NP genes of the ...isolates in Siberia and those in Hokkaido, Japan on their flyway of migration from Siberia to the south in autumn revealed that they belong to the Eurasian lineage of avian influenza viruses. It is noted that the genes of the isolates in Siberia are closely related to those of H5N1 influenza virus strains isolated from chickens and humans in Hong Kong in 1997 as well as to those of isolates from domestic birds in southern China. The results indicate that influenza viruses perpetuated in ducks nesting in Siberia should have contributed genes in the emergence of the H5N1 virusin Hong Kong. Vaccine prepared from avirulent A/duck/Hokkaido/4/96 (H5N3) influenza virus was potent enough to protect mice from challenge with lethal dose of the pathogenic H5N1 virus 19. Intensive surveillance study of aquatic birds especially in Siberia is, therefore, stressed to provide information on the future pandemic influenza virus strains and for vaccine preparation.
We propose a new imaging γ-ray detector in the MeV region. By measuring the directions and energies of not only a scattered γ-ray, but also a recoil electron, the direction of an incident γ-ray would ...be essentially reconstructed event by event. Furthermore, one of two measured (zenith and azimuth) angles of a recoil electron gives us an additional redundancy which enables us to reject the background events by kinematic constraints. In order to, measure the track of a recoil electron, the micro time projection chamber (μ-TPC) has been developed, which can measure the successive positions of the track of charged particles in a few hundred micron meter pitch. The μ-TPC consists of the new type of a gas proportional chamber: micro Pixel gas chamber (μ-PIC), which is one of wireless gas chambers and expected to be robust and stable. Using this μ-TPC and the Anger camera for the detection of a scattered γ-ray, we have obtained the first γ-ray image by the full reconstruction of the direction of γ-rays event by event.
A congestion-controlled optical burst switching network that offers connection guarantees was designed to handle bursts as short as 100 ms with switching within 10 ms in networks less than 200 km ...long. Its optical burst switching (OBS) is based on circuit switching, and transport is by optical burst paths. Five metrics are proposed for evaluating OBS network performance. The application area to be laid and the data application were determined in accordance with the design target. Given a reasonable burst block probability requirement, design criteria are developed on the basis of wavelength switching and conversion implementation. OBS network performance is tested in field trials on the Japan Gigabit Network II testbed. Fast congestion control through the use of precalculated detour routes is demonstrated.
A novel design of the MeV gamma-ray imaging detector with Micro-TPC Orito, R; Kubo, H; Miuchi, K ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2003, Letnik:
513, Številka:
1
Journal Article
Recenzirano
A new type of MeV gamma-ray imaging detector in the energy band from 0.2 to 30
MeV, based on a gaseous time projection chamber with Micro Pixel Chamber (Micro-TPC), is proposed. This detector ...consists of a gas chamber and a scintillation camera. The Micro Pixel Chamber (μ-PIC) has pixel type anodes and cathodes with 400
μm pitch, which enables it to measure the fine tracks of electrons or positrons in Compton scattering or pair creation. The scintillation camera measures the positions and energies of Compton-scattered gamma-rays, electrons and positrons by pair creation. Using information from both the gas chamber and scintillation camera, the incident gamma-rays can be reconstructed event-by-event with high angular resolution. Simulation of the detector performance and the status of the prototype are reported.
The first field experiment of virtual grouped-wavelength-path switching is successfully demonstrated by using polarization-independent multichannel wavelength conversion in a quasi-phase-matched ...lithium niobate waveguide and an 8times8 matrix switch. Contention resolution functionality is confirmed by using wavebands composed of 25GHz spaced, 8- or 64-ch, 10 Gb/s wavelength division multiplexing signals, transmitted through field-installed fibers in Japan Gigabit Network II optical test bed
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