A long-term global atmospheric reanalysis, named ''Japanese 25-year Reanalysis (JRA-25)'' was completed using the Japan Meteorological Agency (JMA) numerical assimilation and forecast system. The analysis covers the period from 1979 to 2004. This is the first long-term reanalysis undertaken in Asia. JMA's latest numerical assimilation system, and specially collected observational data, were used to generate a consistent and high-quality reanalysis dataset designed for climate research and operational monitoring and forecasts. One of the many purposes of JRA-25 is to enhance the analysis to a high quality in the Asian region.Six-hourly data assimilation cycles were performed, producing 6-hourly atmospheric analysis and forecast fields of various physical variables. The global model used in JRA-25 has a spectral resolution of T106 (equivalent to a horizontal grid size of around 120 km) and 40 vertical layers with the top level at 0.4 hPa. In addition to conventional surface and upper air observations, atmospheric motion vector (AMV) wind retrieved from geostationary satellites, brightness temperature from TIROS Operational Vertical Sounder (TOVS), precipitable water retrieved from orbital satellite microwave radiometer radiance and other satellite data are assimilated with three-dimensional variational method (3D-Var). JMA produced daily sea surface temperature (SST), sea ice and three-dimensional ozone profiles for JRA-25. A new quality control method for TOVS data was developed and applied in advance.Many advantages have been found in the JRA-25 reanalysis. Predicted 6-hour global total precipitation distribution and amount are well reproduced both in space and time. The performance of the long time series of the global precipitation is the best among the other reanalyses, with few unrealistic variations from degraded satellite data contaminated by volcanic eruptions. Secondly, JRA-25 is the first reanalysis to assimilate wind profiles around tropical cyclones reconstructed from historical best track information; tropical cyclones were analyzed properly in all the global regions. Additionally, low-level cloud along the subtropical western coast of continents is well simulated and snow depth analysis is also of a good quality. The article also covers material which requires attention when using JRA-25.

Augmented reality (AR) is an imaging technology by which virtual objects are overlaid onto images of real objects captured in real time by a tracking camera. This study aimed to introduce a novel AR guidance system called virtual protractor with augmented reality (VIPAR) to visualize a needle trajectory in 3D space during percutaneous vertebroplasty (PVP). The AR system used for this study comprised a head-mount display (HMD) with a tracking camera and a marker sheet. An augmented scene was created by overlaying the preoperatively generated needle trajectory path onto a marker detected on the patient using AR software, thereby providing the surgeon with augmented views in real time through the HMD. The accuracy of the system was evaluated by using a computer-generated simulation model in a spine phantom and also evaluated clinically in 5 patients. In the 40 spine phantom trials, the error of the insertion angle (EIA), defined as the difference between the attempted angle and the insertion angle, was evaluated using 3D CT scanning. Computed tomography analysis of the 40 spine phantom trials showed that the EIA in the axial plane significantly improved when VIPAR was used compared with when it was not used (0.96° ± 0.61° vs 4.34° ± 2.36°, respectively). The same held true for EIA in the sagittal plane (0.61° ± 0.70° vs 2.55° ± 1.93°, respectively). In the clinical evaluation of the AR system, 5 patients with osteoporotic vertebral fractures underwent VIPAR-guided PVP from October 2011 to May 2012. The postoperative EIA was evaluated using CT. The clinical results of the 5 patients showed that the EIA in all 10 needle insertions was 2.09° ± 1.3° in the axial plane and 1.98° ± 1.8° in the sagittal plane. There was no pedicle breach or leakage of polymethylmethacrylate. VIPAR was successfully used to assist in needle insertion during PVP by providing the surgeon with an ideal insertion point and needle trajectory through the HMD. The findings indicate that AR guidance technology can become a useful assistive device during spine surgeries requiring percutaneous procedures.

SUMMARYThe progress and status of a new atmospheric re-analysis, JRA-25 the Japanese 25-year Re-analysis which covers the 26 years from 1979 to 2004, are introduced. Observational data include some newly produced for JRA-25 and advantages and drawbacks of performance are briefly described. JRA-25 has many advantages such as its handling of precipitation amounts, tropical cyclone analysis, and the extent of low-level cloud along western continents that are among the best compared to other re-analyses. The snow analysis is also good and stable. JRA-25 outputs analysis products every 6 hours.

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We have developed a high-density H2 plasma source excited by helicon-wave discharge. By optimizing the antenna shape, the diameter of the discharge tube, and the magnetic field strength, a high electron density close to 1×1013 cm-3 was achieved at an rf power of 3 kW and a H2 gas pressure of 30 mTorr. The high-density H2 plasma source can be used as a compact divertor simulator in nuclear fusion research.

In order to examine the initiation mechanism of delamination in ultrahigh molecular weight polyethylene (UHMWPE) knee components, a bi-directional sliding fatigue test was performed for three types of UHMWPE specimens: nonirradiated, gamma-irradiated (25 kGy) and gamma-irradiated (25 kGy) with 0.1% vitamin E added. Sliding surfaces of post-tested UHMWPE specimens were observed using an optical microscope and a scanning electron microscope. Also, surface roughness was measured at the sliding surfaces of UHMWPE specimens. Delamination was observed only in gamma-irradiated specimens. A networked structure of surface asperity that resembled grain boundary was observed prior to delamination in gamma-irradiated specimens. Surface roughness in the gamma-irradiated specimens, higher than in any other specimen, showed a rapid increase prior to delamination. Detailed observation using an optical microscope and a scanning electron microscope showed microscopic crack initiation along subsurface grain boundaries in gamma-irradiated specimens. These results suggest that subsurface crack initiation is a precursor of delamination and is accelerated by oxidative degradation due to gamma irradiation. Of the three types of specimens, UHMWPE with vitamin E added showed the lowest surface roughness values at all measuring points. The addition of vitamin E is effective in improving wear resistance and fatigue performance of UHMWPE.