427 research outputs found

    Episodic transient deformation revealed by the analysis of multiple GNSS networks in the Noto Peninsula, central Japan

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    流体とスロースリップに駆動された能登半島群発地震 --ソフトバンク独自基準点データを用いた地殻変動解析結果--. 京都大学プレスリリース. 2023-06-13.Since November 30, 2020, an intense seismic swarm and transient deformation have been continuously observed in the Noto Peninsula, central Japan, which is a non-volcanic/geothermal area far from major plate boundaries. We modeled transient deformation based on a combined analysis of multiple Global Navigation Satellite System (GNSS) observation networks, including one operated by a private sector company (SoftBank Corp.), relocated earthquake hypocenters, and tectonic settings. Our analysis showed a total displacement pattern over 2 years shows horizontal inflation and uplift of up to ~ 70 mm around the source of the earthquake swarm. In the first 3 months, the opening of the shallow-dipping tensile crack had an estimated volumetric increase of ~ 1.4 × 10⁷ m³ at a depth of ~ 16 km. Over the next 15 months, the observed deformation was well reproduced by shear-tensile sources, which represent an aseismic reverse-type slip and the opening of a southeast-dipping fault zone at a depth of 14–16 km. We suggest that the upwelling fluid spread at a depth of ~ 16 km through an existing shallow-dipping permeable fault zone and then diffused into the fault zone, triggering a long-lasting sub-meter aseismic slip below the seismogenic depth. The aseismic slip further triggered intense earthquake swarms at the updip

    Host Galaxies of Hard X-ray Selected Type-2 Active Galactic Nuclei at Intermediate Redshifts

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    We study properties of the host galaxies of 15 hard X-ray selected type-2 active galactic nuclei (AGNs) at intermediate redshifts (0.05<z<<z<0.6) detected in ASCAASCA surveys. The absorption corrected hard X-ray luminosities L210keVL_{\rm 2-10 keV} range from 1042^{42} erg s1^{-1} to 104510^{45} erg s1^{-1}. We took the RR-band image of these AGNs with the University of Hawaii 2.2 m telescope. Thanks to the intrinsic obscuration of nuclear light, we can decompose the galaxies with a spheroid component and a disk component. The resulting spheroid luminosities correlate with L210keVL_{\rm 2-10 keV}; higher (lower) X-ray luminosity AGNs tend to reside in luminous (less luminous) spheroids. It is also found that the hosts of luminous AGNs show a large spheroid-to-disk luminosity ratio (\sim1), while those of less luminous AGNs spread between 0 and 1. The correlation between L210keVL_{\rm 2-10keV} and spheroid luminosity indicates that the relation between mass of a supermassive black hole (SMBH) and spheroid luminosity (BS-relation) at the intermediate redshifts. The BS-relation agrees with that in the local universe if the Eddington ratio of 0.24 is adopted, which is a mean value determined from our ASCAASCA type-1 AGN sample at similar redshifts through the broad-line width and continuum luminosity. The present study demonstrates the effectiveness of using type-2 AGNs at high redshifts to study their host properties.Comment: 21 pages, 8 figures, ApJ accepte

    Trajectory analysis for fusion path in superheavy-mass region

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    We propose an effective method for the precise investigation of the fusion-fission mechanism in the superheavy-mass region, using the fluctuation-dissipation model. The trajectory calculation with friction is performed in the nuclear deformation space using the Langevin equation. In the reaction 48^{48}Ca+244^{244}Pu, the trajectories are classified into the fusion-fission process, the quasi-fission process and the deep quasi-fission process. By analyzing the time evolution of each trajectory, the mechanism of each process is clearly revealed, i.e., it is explained why a trajectory takes a characteristic path in this model. We discuss, in particular, the condition under which the fusion path is followed, which is crucial in the discussion of the possibility of synthesizing superheavy elements.Comment: 25 pages, 12 figures, accepted for publication in Nuclear Physics

    Successful Endoscopic Resection of an Early Carcinoma of the Duodenum

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    We describe a patient in whom an early carcinoma of the duodenum was able to be resected endoscopically. A 77-year-old man presented with epigastric pain. Upper gastrointestinal endoscopy revealed a mass in the duodenum, and the patient was admitted. A whitish nodular aggregated lesion, measuring 20 mm in diameter, was found in the second portion of the duodenum. Examination of a biopsy specimen showed a Group III tubular adenoma. Endoscopic ultrasonography showed that the lesion was confined to the mucosa. The large size of the lesion suggested the possibility of malignancy. Endoscopic mucosal resection was therefore performed. Histopathologically, the diagnosis was carcinoma in adenoma. The depth of invasion was mucosal. We conclude that endoscopic muosal resection can be used to treat mucosal lesions arising in the duodenum
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