The Fukushima Daiichi Nuclear Power Station (FDNPS), operated by Tokyo Electric Power Company Holdings, Inc., went into meltdown after the large tsunami caused by the Great East Japan Earthquake of ...March 11, 2011. Very large amounts of radionuclides were released from the damaged plant. Radiation distribution measurements inside FDNPS buildings are indispensable to execute decommissioning tasks in the reactor buildings. We have developed a compact Compton camera to measure the distribution of radioactive contamination inside the FDNPS buildings three-dimensionally (3D). The total weight of the Compton camera is lower than 1.0 kg. The gamma-ray sensor of the Compton camera employs Ce-doped GAGG (Gd3Al2Ga3O12) scintillators coupled with a multi-pixel photon counter. Angular correction of the detection efficiency of the Compton camera was conducted. Moreover, we developed a 3D back-projection method using the multi-angle data measured with the Compton camera. We successfully observed 3D radiation images resulting from the two 137Cs radioactive sources, and the image of the 9.2 MBq source appeared stronger than that of the 2.7 MBq source.
Evidence for a large-scale supergalactic cosmic-ray multiplet (arrival directions correlated with energy) structure is reported for ultra-high-energy cosmic-ray (UHECR) energies above 1019 eV using 7 ...years of data from the Telescope Array (TA) surface detector and updated to 10 years. Previous energy-position correlation studies have made assumptions regarding magnetic field shapes and strength, and UHECR composition. Here the assumption tested is that, because the supergalactic plane is a fit to the average matter density of the local large-scale structure, UHECR sources and intervening extragalactic magnetic fields are correlated with this plane. This supergalactic deflection hypothesis is tested by the entire field-of-view (FOV) behavior of the strength of intermediate-scale energy-angle correlations. These multiplets are measured in spherical cap section bins (wedges) of the FOV to account for coherent and random magnetic fields. The structure found is consistent with supergalactic deflection, the previously published energy spectrum anisotropy results of the TA (the Hotspot and Coldspot), and toy-model simulations of a supergalactic magnetic sheet. The seven year data posttrial significance of this supergalactic structure of multiplets appearing by chance, on an isotropic sky, is found by Monte Carlo simulation to be 4.2 . The 10 years of data posttrial significance is 4.1 . Furthermore, the starburst galaxy M82 is shown to be a possible source of the TA Hotspot, and an estimate of the supergalactic magnetic field using UHECR measurements is presented.
In this paper, we present the first high‐speed video observation of a cloud‐to‐ground lightning flash and its associated downward‐directed Terrestrial Gamma‐ray Flash (TGF). The optical emission of ...the event was observed by a high‐speed video camera running at 40,000 frames per second in conjunction with the Telescope Array Surface Detector, Lightning Mapping Array, interferometer, electric‐field fast antenna, and the National Lightning Detection Network. The cloud‐to‐ground flash associated with the observed TGF was formed by a fast downward leader followed by a very intense return stroke peak current of −154 kA. The TGF occurred while the downward leader was below cloud base, and even when it was halfway in its propagation to ground. The suite of gamma‐ray and lightning instruments, timing resolution, and source proximity offer us detailed information and therefore a unique look at the TGF phenomena.
Plain Language Summary
This study provides the very first simultaneous observations of a downward‐directed terrestrial gamma‐ray flash (TGF) together with its associated cloud‐to‐ground lightning flash using a high‐speed camera in addition to gamma‐ray and radio measurements. The camera, running at 40,000 frames per second, allowed us to check the characteristics of the downward leader, the development stage of the lightning flash, and the luminosity variations in coincidence with TGF production.
Key Points
Simultaneous recordings of a downward‐directed terrestrial gamma‐ray flash (TGF), high‐speed video images, and radio emissions
TGF events occurred while the leader was already branching below cloud base and even when it was halfway in its propagation to ground
Energetic downward‐directed TGFs were associated with fast downward leaders that produced high return stroke peak currents
The CALorimetric Electron Telescope (CALET)on the International Space Station consists of a high-energy cosmic-ray CALorimeter (CAL)and a lower-energy CALET Gamma-ray Burst Monitor (CGBM). CAL is ...sensitive to electrons up to 20 TeV, cosmic-ray nuclei from Z=1 throughZ∼40, and gamma rays over the range1 GeV–10 TeV. CGBM observes gamma rays from 7 keV to 20 MeV. The combined CAL-CGBM instrument has conducted a search for gamma-ray bursts (GRBs)since 2015 October. We report here on the results of a search for X-ray/gamma-ray counterparts to gravitational-wave events reported during the LIGO/Virgo observing run O3. No events have been detected that pass all acceptance criteria. We describe the components, performance, and triggering algorithms of the CGBM—the two Hard X-ray Monitors consisting of LaBr3(Ce)scintillators sensitive to 7 keV–1 MeV gamma rays and a Soft Gamma-ray Monitor BGO scintillator sensitive to 40 keV–20 MeV—and the high-energy CAL consisting of a charge detection module, imaging calorimeter, and the fully active total absorption calorimeter. The analysis procedure is described and upper limits to the time-averaged fluxes are presented.
The relationship between lymphovascular invasion (LVI) and prognosis in patients with superficial esophageal squamous cell carcinoma (SESCC) is unclear. The aim of this study is to evaluate ...prognostic factors in patients with lymph node-negative SESCC. A total of 195 patients with pathologically confirmed T1a-MM, T1b, and lymph node-negative SESCC were retrospectively reviewed in this study. Overall, the disease-free survival (DFS) rate was poorer in the lymphatic invasion-positive group than in the lymphatic invasion-negative group (p = 0.002) and a multivariate analysis suggested that lymphatic invasion was the only independent prognostic factor of DFS in patients with lymph node-negative SESCC (HR = 4.075, p = 0.005). Distant organ recurrence occurred in one patient (1/52, 1.9%) in the T1b-SM2 group and in six patients (6/61, 9.7%) in the T1b-SM3 group; all of these patients had LVI. LVI-positive patients had a poorer DFS than invasion-negative patients in the T1b-SM2 and SM3 groups (p = 0.026), and a multivariate analysis suggested that LVI was the only independent prognostic factor of DFS in patients with lymph node-negative SM2 and SM3 SESCC (HR = 5.165, p = 0.031). Lymph node-positive patients had a significantly poorer DFS rate than lymph node negative and LVI positive patients among the SM2 and SM3 SESCC patients (p = 0.018). The present results suggested that LVI was an independent prognostic factor in patients with SM2 and SM3 lymph node-negative SESCC; however their prognosis was not worse than that of patients with lymph node-positive SM2 and SM3 SESCC, for whom adjuvant therapy is indicated as a standard treatment.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
We report on the measurements performed with relativistic ions from Be to Fe, at the Fragment Separator (FRS) of the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt, to test the ...performance of charge-sensitive detectors that were designed to separate – via multiple dE/dx measurements – fully stripped nuclei of cosmic origin in the experiment CALET. The latter is a space mission by the Japanese Space Agency (JAXA) scheduled to be launched to the International Space Station (ISS) in 2013. The CALET instrument is managed by an international collaboration and it is scheduled to take data for 5 years on the Exposure Facility (JEM-EF) of the Japanese module KIBO on the ISS.
The aim of the test was to accurately measure the response of the scintillator to different nuclear species and parametrize the saturation of the scintillation light in order to assess the impact of this effect on the charge resolution of the instrument.
► Charge identification of relativistic cosmic nuclei. ► Saturation of scintillation light from ionization by heavy nuclei. ► Charge resolution with scintillators with high Z ionizing radiation.
The surface tension of molten nickel was measured under a reducing gas atmosphere of Ar–He–5 vol% H
2
by an oscillating droplet method using electromagnetic levitation. The influence of the ...temperature dependence of the oxygen partial pressure of the gas on the surface tension was investigated. The surface tension of molten nickel was successfully measured over the very wide temperature range of 750 K, which included undercooling conditions. The temperature dependence of the surface tension did not exhibit a linear relationship but had a peculiar kink at around 1600 K, due to competition between the temperature dependence of the oxygen partial pressure and that of the oxygen adsorption equilibrium constant.
Background
Variations in institutional practice may contribute to different outcomes of cancer treatment. The impact of interinstitutional heterogeneity on outcomes between hospitals after ...oesophagectomy has not been examined previously using data from surgical clinical trials.
Methods
The data from two phase III trials for oesophageal cancer were used. Japan Clinical Oncology Group (JCOG) 9204 involved oesophagectomy (92‐OP) versus oesophagectomy plus postoperative chemotherapy (92‐POST), with accrual from 1992 to 1997. JCOG9907 involved postoperative chemotherapy (99‐POST) versus preoperative chemotherapy (99‐PRE), with accrual from 2000 to 2006. Hospitals contributing fewer than three patients were excluded. The influence of time and preoperative chemotherapy on interinstitutional heterogeneity related to postoperative complications and 5‐year overall survival were evaluated by comparisons within and between these trial groups. Heterogeneity was estimated by a mixed‐effects model after adjusting for age, sex, performance status, location of the primary tumour and clinical stage.
Results
Twelve hospitals in 92‐OP (114 patients), 13 in 92‐POST (114), 19 in 99‐POST (158) and 18 in 99‐PRE (154) were eligible. There was considerable heterogeneity in predicted postoperative complications in both groups in JCOG9204 (median 31·3 (range 15·0–68·2) per cent), and in 99‐PRE (35·2 (22·6–46·6) per cent) but not in 99‐POST (27·7 (27·7–27·7) per cent) from JCOG9907. A similar pattern was seen for predicted overall survival (92‐POST: 66·4 (range 64·1–68·9) per cent; 99‐PRE: 55·9 (54·0–59·7) per cent; 99‐POST: 44·4 (44·4–44·4) per cent).
Conclusion
Interinstitutional heterogeneity regarding complications and survival after oesophagectomy is a problem that merits wider consideration.
Heterogeneity is still a problem in surgical RCTs
The Fukushima Daiichi Nuclear Power Station (FDNPS), operated by Tokyo Electric Power Company Holdings, Inc., suffered a meltdown after a large tsunami caused by the Great East Japan Earthquake on ...March 11, 2011. The measurement of radiation distribution inside FDNPS buildings is indispensable for executing appropriate decommissioning tasks in the reactor's buildings. In addition, it is extremely important to accurately predict the location of radioactive contamination beforehand because the working time is limited owing to radiation exposure to workers. In this paper, a simple virtual reality (VR) system that can detect radioactive substances in virtual space has been developed to simulate real working environments. A three-dimensional (3D) photo-based model of the real working environment, including an image of the radioactive substance, was imported into the virtual space of the VR system. The developed VR system can be accessed using a smartphone and a cardboard goggle. The VR system is expected to be useful for preliminary training of workers and for recognizing radioactive hotspots during decommissioning of the work environment.
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