93 research outputs found

    CURRENT STATUS ON HIGH PERFORMANCE COMPUTING FOR VEHICLE AERODYNAMICS USING LARGE EDDY SIMULATION

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    ABSTRACT The world's largest class unsteady turbulence simulations of flow around vehicles were conducted using Large Eddy Simulation (LES) on the Earth Simulator in Japan. The main objective of our study is to investigate the validity of LES, as an alternative to a conventional wind tunnel measurement or the Reynolds Averaged Navier-Stokes method, for the assessment of vehicle £ Address all correspondence to this author

    Case Report Case Report of Atlantoaxial Rotatory Fixation after Cochlear Implantation

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    Atlantoaxial rotatory fixation (AARF) is a relatively rare condition and is mainly seen in children. We report of a 7-year-old girl suffering from AARF after cochlear implantation (CI). Fortunately, early diagnosis based on three-dimensional computed tomography (3DCT) was made, and the patient was cured with conservative therapy. Nontraumatic AARF, which is also known as Grisel's syndrome and occurs subsequent to neck infections or ear, nose, and throat (ENT) surgery, represents only a small fraction of AARF cases. Two factors are mainly thought to contribute to the pathogenesis of the condition estimated, namely, (i) neck immaturity in children and (ii) infiltration by inflammatory mediators around the upper neck joint, easily permitted by the neck vasculature. AARF should be suspected in case of torticollis developing after ENT surgery

    International Pellet Watch: global monitoring of persistent organic pollutants (POPs) in coastal waters. 1. Initial phase data on PCBs, DDTs, and HCHs

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    Samples of polyethylene pellets were collected at 30 beaches from 17 countries and analyzed for organochlorine compounds. PCB concentrations in the pellets were highest on US coasts, followed by western Europe and Japan, and were lower in tropical Asia, southern Africa and Australia. This spatial pattern reflected regional differences in the usage of PCBs and was positively correlated with data from Mussel Watch, another monitoring approach. DDTs showed high concentrations on the US west coast and in Vietnam. In Vietnam, DDT was predominant over its metabolites (DDE and DDD), suggesting the principal source may be current usage of the pesticide for malaria control. High concentrations of pesticide HCHs were detected in the pellets from southern Africa, suggesting current usage of the pesticides in southern Africa. This study demonstrates the utility and feasibility of the International Pellet Watch approach to monitor POPs at a global scale

    Clonal hematopoiesis in adult pure red cell aplasia

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    Idiopathic pure red cell aplasia (PRCA) and secondary PRCA associated with thymoma and large granular lymphocyte leukemia are generally considered to be immune-mediated. The PRCA2004/2006 study showed that poor responses to immunosuppression and anemia relapse were associated with death. PRCA may represent the prodrome to MDS. Thus, clonal hematopoiesis may be responsible for treatment failure. We investigated gene mutations in myeloid neoplasm-associated genes in acquired PRCA. We identified 21 mutations affecting amino acid sequences in 11 of the 38 adult PRCA patients (28.9%) using stringent filtering of the error-prone sequences and SNPs. Four PRCA patients showed 7 driver mutations in TET2, DNMT3A and KDM6A, and 2 PRCA patients carried multiple mutations in TET2. Five PRCA patients had mutations with high VAFs exceeding 0.3. These results suggest that clonal hematopoiesis by stem/progenitor cells might be related to the pathophysiology of chronic PRCA in certain adult patients

    Hitomi (ASTRO-H) X-ray Astronomy Satellite

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    The Hitomi (ASTRO-H) mission is the sixth Japanese x-ray astronomy satellite developed by a large international collaboration, including Japan, USA, Canada, and Europe. The mission aimed to provide the highest energy resolution ever achieved at E  >  2  keV, using a microcalorimeter instrument, and to cover a wide energy range spanning four decades in energy from soft x-rays to gamma rays. After a successful launch on February 17, 2016, the spacecraft lost its function on March 26, 2016, but the commissioning phase for about a month provided valuable information on the onboard instruments and the spacecraft system, including astrophysical results obtained from first light observations. The paper describes the Hitomi (ASTRO-H) mission, its capabilities, the initial operation, and the instruments/spacecraft performances confirmed during the commissioning operations for about a month

    Underground behavior of overwintering Tokyo daruma pond frogs in early spring

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    Although Tokyo daruma pond frogs (Pelophylax porosus porosus) were once commonly observed throughout paddy fields in Japan, their populations have recently declined. The mode by which frogs survive during the overwintering period is largely unknown. In this study, we observed the underground behavior of 12 free-living Tokyo daruma pond frogs that overwintered in paddy soil and a dry field by periodically excavating their overwintering positions from late March to early May. The mean overwintering depth of these frogs was similar to 19.8 cm, with 10 having migrated toward the soil surface (mean depth: similar to 8.6 cm) by late March, and finally, all 11 live frogs migrated further upward close to the soil surface. In addition, males tended to emerge earlier in spring than females. One monitored frog in the paddy soil that migrated close to the soil surface died, presumably from plowing. Aside from the 12 study frogs, several other mutilated frog corpses were found in the paddies. This species starts migrating to the soil surface during the same period when human disturbances begin, making the frogs vulnerable to these disturbances during this period. Consequently, it is necessary to facilitate the emergence of frogs to protect them from human disturbances-e.g., by temporarily filling fields with water

    Computational visualization of unsteady flow around vehicles using high performance computing

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    One of the largest-scale unstructured Large Eddy Simulation (LES) of flow around a full-scale road vehicle is conducted on the Earth Simulator in Japan. The main objective of our study is to look into the validity of LES for the assessment of vehicle aerodynamics, especially in the context of its possibility for unsteady or transient aerodynamic forces. Firstly, the aerodynamic LES proposed is quantitatively validated on the ASMO simplified model by comparing the mean pressure distributions on the vehicle surface with those obtained by a conventional Reynolds-Averaged Navier-Stokes simulation (RANS) or a wind tunnel measurement. Then, the method is applied to the full-scale vehicle with complicated geometry to qualitatively investigate the capability of capturing organized flow structures around the vehicle. Finally, unsteady aerodynamic forces acting on the vehicle in transient yawing-angle change are estimated and relationship between the flow structures and the transient aerodynamic forces is mentioned. As a result, it is demonstrated that LES will be a powerful tool for the vehicle aerodynamic assessment in the foreseeable future, because it can provide precious aerodynamic data which conventional wind tunnel tests or RANS simulations are difficult to provide
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