31 research outputs found

    Observation results by the TAMA300 detector on gravitational wave bursts from stellar-core collapses

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    We present data-analysis schemes and results of observations with the TAMA300 gravitational-wave detector, targeting burst signals from stellar-core collapse events. In analyses for burst gravitational waves, the detection and fake-reduction schemes are different from well-investigated ones for a chirp-wave analysis, because precise waveform templates are not available. We used an excess-power filter for the extraction of gravitational-wave candidates, and developed two methods for the reduction of fake events caused by non-stationary noises of the detector. These analysis schemes were applied to real data from the TAMA300 interferometric gravitational wave detector. As a result, fake events were reduced by a factor of about 1000 in the best cases. The resultant event candidates were interpreted from an astronomical viewpoint. We set an upper limit of 2.2x10^3 events/sec on the burst gravitational-wave event rate in our Galaxy with a confidence level of 90%. This work sets a milestone and prospects on the search for burst gravitational waves, by establishing an analysis scheme for the observation data from an interferometric gravitational wave detector

    Estimation of selectivity curve of Danish seine for Japanese sandfish Arctoscopus japonicus off Tottori Prefecture

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    Bycatch of immature Japanese sandfish Arctoscopus japonicas in Danish seine fishery is an issue in Tottori Prefecture. To manage the size of fish caught, mesh selectivity should be understood. This study aims to estimate a master curve of selectivity and to evaluate an adequate codend mesh size of Danish seine in this area. The sea experiment was conducted using three mesh sizes (43.0, 34.2, 30.0 mm) for codend with cover net under the same condition of the commercial fishery. The estimated master curves are compared in total of four ways which consist of two kinds of data sets (Whole set and AIC min) and two kinds of estimation methods (Separate and Simultaneous). From this result, it was concluded that the 43.0 mm mesh size was the most effective to decreasing the catch of immature sandfish preventing a decrease in the amount of mature fish

    Indications of extracorporeal surgery (autotransplantation) for upper urinary tumors and renal calculi

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    Renal preservation and cure of bilateral occurrence of renal tumors or stones as well as occurrence in solitary kidney put all urologists on the thorns of dilemma. Application of extracorporeal surgery resulting in autotransplantation of the kidney for such complicated cases seems useful. Case 1 was a bilateral renal Wilms' tumors in a 17-month-old boy, case 2 and 3 were undiagnosed tumors in renal pelvis and ureter. Extracorporeal surgery enables an accurate partial nephrectomy and yet helps to avoid not only the dissemination of tumor cells, but also undesired nephrectomy in case of benign origin. On the contrary, bilateral nephrectomy followed by dialysis or homo-transplantation will result in an immunosuppressive state and the radicality may only be temporary. Besides, the 5-year survival of dialysis therapy is in the range of 60-65%. Thus the indication of autotransplantation was signified in the tumor situation of case 1. For the 2nd and 3rd cases, this method seems to be the best in satisfying the dilemma in discussion. Likewise, the complicated renal calculi could be completely removed without further deterioration of renal function if they were extracorporeally treated and autotransplanted. We proved that 83% of the difficult stones can be completely removed under hypothermia in situ. For application of autotransplantation to the calculous disease, we feel observation of contraindication is essential for better results at this stage
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