Current status of Japanese detectors

Current status of TAMA and CLIO detectors in Japan is reported in this article. These two interferometric gravitational-wave detectors are being developed for the large cryogenic gravitational wave telescope (LCGT) which is a future plan for detecting gravitational wave signals at least once per year. TAMA300 is being upgraded to improve the sensitivity in low frequency region after the last observation experiment in 2004. To reduce the seismic noises, we are installing new seismic isolation system, which is called TAMA Seismic Attenuation System, for the four test masses. We confirmed stable mass locks of a cavity and improvements of length and angular fluctuations by using two SASs. We are currently optimizing the performance of the third and fourth SASs. We continue TAMA300 operation and R&D studies for LCGT. Next data taking in the summer of 2007 is planned. CLIO is a 100-m baseline length prototype detector for LCGT to investigate interferometer performance in cryogenic condition. The key features of CLIO are that it locates Kamioka underground site for low seismic noise level, and adopts cryogenic Sapphire mirrors for low thermal noise level. The first operation of the cryogenic interferometer was successfully demonstrated in February of 2006. Current sensitivity at room temperature is close to the target sensitivity within a factor of 4. Several observation experiments at room temperature have been done. Once the displacement noise reaches at thermal noise level of room temperature, its improvement by cooling test mass mirrors should be demonstrated.Comment: 6 pages, 5 figures, Proceedings of GWDAW-1

Coincidence analysis to search for inspiraling compact binaries using TAMA300 and LISM data

Japanese laser interferometric gravitational wave detectors, TAMA300 and LISM, performed a coincident observation during 2001. We perform a coincidence analysis to search for inspiraling compact binaries. The length of data used for the coincidence analysis is 275 hours when both TAMA300 and LISM detectors are operated simultaneously. TAMA300 and LISM data are analyzed by matched filtering, and candidates for gravitational wave events are obtained. If there is a true gravitational wave signal, it should appear in both data of detectors with consistent waveforms characterized by masses of stars, amplitude of the signal, the coalescence time and so on. We introduce a set of coincidence conditions of the parameters, and search for coincident events. This procedure reduces the number of fake events considerably, by a factor $\sim 10^{-4}$ compared with the number of fake events in single detector analysis. We find that the number of events after imposing the coincidence conditions is consistent with the number of accidental coincidences produced purely by noise. We thus find no evidence of gravitational wave signals. We obtain an upper limit of 0.046 /hours (CL $= 90$) to the Galactic event rate within 1kpc from the Earth. The method used in this paper can be applied straightforwardly to the case of coincidence observations with more than two detectors with arbitrary arm directions.Comment: 28 pages, 17 figures, Replaced with the version to be published in Physical Review

Results of the search for inspiraling compact star binaries from TAMA300's observation in 2000-2004

We analyze the data of TAMA300 detector to search for gravitational waves from inspiraling compact star binaries with masses of the component stars in the range 1-3Msolar. In this analysis, 2705 hours of data, taken during the years 2000-2004, are used for the event search. We combine the results of different observation runs, and obtained a single upper limit on the rate of the coalescence of compact binaries in our Galaxy of 20 per year at a 90% confidence level. In this upper limit, the effect of various systematic errors such like the uncertainty of the background estimation and the calibration of the detector's sensitivity are included.Comment: 8 pages, 4 Postscript figures, uses revtex4.sty The author list was correcte

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

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

蔬菜水耕栽培の実用化に関する研究 XIV : 生育段階別の溶存酸素供給量の差異がトマトの生育と収量におよぼす影響(農学部門)

春作と秋作において大型福寿トマトを水耕栽培し, 栄養生長期, 開花結実期, 果実肥大期の一時期のみ培養液の溶存酸素供給量を多くして, 生育段階により溶存酸素濃度に敏感な時期があるかどうか, 生育, 収量にどのような影響をおよぼすかを調べた。開花結実期または果実肥大期に酸素供給量を多くすることにより, 開花から果実収穫までの日数が短くなった。生育の一時期に溶存酸素供給量を多くすることによる, 生育, 栄養・水吸収量, 収量におよぼす影響はほとんどなかった。酸素供給量の多い状態から標準供給量にもどした場合, 根腐れ症状がみられた。Tomato variety "Ohgata-Fukujyu" was water-cultured as spring and fall crops, where dissolved oxygen supply to the nutrient solution was increased at each of the vegetative growth stage, the flowering and fruit setting stage and the fruit developing stage. The effect of temporarily increasing the oxygen supply was studied in relation to the following factors : oxygen concentration, pH and electric conductivity of the nutrient solution, NO_3-N, P, K, Ca, Mg, Fe and water absorption, plant weight and size, root appearance, mineral composition of plant parts, yield and length of time required for fruit development. Effect of increased oxygen supply to the nutrient solution at one of the growth stages on growth, nutrient and water absorption and yield of the tomato was little, if any. The length of time required for fruit development, that is, the number of days from anthesis to harvest-ripeness of the indivisual fruit, was shortened when the oxygen supply was increased at the later stage of plant growth

Streptococcus gallolyticus ssp. pasteurianus bacteremia during chemotherapy-induced neutropenia in a patient with malignant lymphoma

Background: Streptococcus gallolyticus ssp. pasteurianus is a commensal bacterium of the alimentary tract in humans and animals. This microorganism not only causes sepsis, endocarditis, and meningitis but is also associated with colorectal tumors. We report herein a rare case of S. gallolyticus ssp. pasteurianus bacteremia in a patient with concomitant colon cancer and aggressive malignant lymphoma during the neutropenic period after chemotherapy against lymphoma. Case presentation: A 79-year-old man was found to have an adenoma in the ascending colon, and endoscopic mucosal resection (EMR) was planned to remove the lesion. However, he was diagnosed with diffuse large B-cell lymphoma during the pre-operation examination. The EMR was postponed, and he received rituximab, cyclophosphamide, etoposide, vincristine, and prednisolone (R-CEOP). He had a neutropenic fever with positive blood cultures for S. gallolyticus ssp. pasteurianus during the first course of R-CEOP. He improved as soon as cefepime was administered. Bacteremia did not recur thereafter, and he underwent EMR after completing six cycles of R-CEOP. The histological diagnosis of the colon tumor was well-differentiated adenocarcinoma in adenoma. Streptococcus gallolyticus ssp. pasteurianus was not detected in the culture of the resected tissue. Conclusion: Although there have been few reports of bloodstream infection due to S. gallolyticus ssp. pasteurianus in patients with hematological malignancies undergoing cytotoxic chemotherapy, physicians should investigate the presence of coexisting colorectal tumors when this bacterium is isolated from blood cultures