視神経脊髄炎スペクトラム病患の臨床免疫学的解析

Tohoku University青木正志課

Application of cloud particle sensor sondes for estimating the number concentration of cloud water droplets and liquid water content: case studies in the Arctic region

A cloud particle sensor (CPS) sonde is an observing system attached with a radiosonde sensor to observe the vertical structure of cloud properties. The signals obtained from CPS sondes are related to the phase, size, and number of cloud particles. The system offers economic advantages including human resource and simple operation costs compared with aircraft measurements and land-/satellite-based remote sensing. However, the observed information should be appropriately corrected because of several uncertainties. Here we made field experiments in the Arctic region by launching approximately 40 CPS sondes between 2018 and 2020. Using these data sets, a better practical correction method was proposed to exclude unreliable data, estimate the effective cloud water droplet radius, and determine a correction factor for the total cloud particle count. We apply this method to data obtained in October 2019 over the Arctic Ocean and March 2020 at Ny-Ålesund, Svalbard, Norway, to compare with a particle counter aboard a tethered balloon and liquid water content retrieved by a microwave radiometer. The estimated total particle count and liquid water content from the CPS sondes generally agree with those data. Although further development and validation of CPS sondes based on dedicated laboratory experiments would be required, the practical correction approach proposed here would offer better advantages in retrieving quantitative information on the vertical distribution of cloud microphysics under the condition of a lower number concentration

Time-series photometry of Earth flyby asteroid 2012 DA14

Context. The object 2012 DA14 is a near-Earth asteroid with a size of several tens of meters. It had approached closely the Earth on 15 February, 2013 UT, providing an opportunity for precise measurements of this tiny asteroid. Aims. The solar phase angle of 2012 DA14 had varied widely around its closest approach but was almost constant during the following night. We performed time-series photometric observations on those two nights to determine the rotational properties and phase effect. Methods. The observations were carried out using the 0.55-m telescope at Saitama University, Japan. The R-band images were obtained continuously over a 2 hr period at the closest approach and for about 5 hr on the next night. Results. The lightcurve data from the second night indicates a rotational period of 11.0 +1.8/-0.6 hr and a peak-to-peak amplitude of 1.59 +/- 0.02 mag. The brightness variation before and after the closest approach was separated into two components that are derived from the rotation and phase effect. We found that the phase curve slope of this asteroid is significantly shallower than those of other L-type asteroids. Conclusions. We suggest that 2012 DA14 is coated with a coarse surface that lacks fine regolith particles and/or a high albedo surface.Comment: 4 pages, 4 figures, accepted for publication in Astronomy and Astrophysic

Unusual drift behaviour of multi-year sea ice in the Beaufort Sea during summer 2018

© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Kimura, N., Tateyama, K., Sato, K., Krishfield, R. A., & Yamaguchi, H. Unusual drift behaviour of multi-year sea ice in the Beaufort Sea during summer 2018. Polar Research, 39, (2020): 3617, doi:10.33265/polar.v39.3617.In summer 2018, thick sea ice blocked the mouth of the Amundsen Gulf (AG), Canada, obstructing shipping through the North-west Passage. This study analysed multi-year ice motion to investigate the source of this thick ice and the reasons for its unusual movement. For this purpose, a daily multi-year ice distribution product was generated by ice tracking using gridded daily sea-ice velocities (2003–2018) derived from the AMSR-E and AMSR-2 data. From autumn 2017 to summer 2018, the area of multi-year ice extended westward to the Beaufort Sea and then migrated towards the AG mouth. The primary cause of the unusual ice cover was anomalous AG-ward wind in September 2018. It is known that multi-year ice has become increasingly moveable over the past decades, as indicated by the increasing wind factor (i.e., ratio of ice-drift speed and wind speed), but the unusual ice motion in the summer of 2018 cannot be explainable by the wind factor alone. Accurately, predicting monthly wind and monitoring old thick ice will reduce the risk posed by thick Arctic sea ice to shipping.This work was a part of the Arctic Challenge for Sustainability (ArCS, Program Grant Number JPMXD1300000000) and the Arctic Challenge for Sustainability II (ArCS II, Program Grant Number JPMXD1420318865) projects

Correlation between fabrication factor and superconducting properties of the Tl-and-Bi-based high-Tc superconductor

Large critical current densities (J(sub c)) were obtained in c axis oriented Tl-1 223/Ag composite tapes fabricated by spraying methods without a vacuum. Transport measurements at 77K under a zero field indicated a J(sub c) of 9 x 10(exp 4) A/sq cm and 7 x 10(exp 3) A/sq cm at 1T for the tapes fabricated by spray pyrolysis. The novel GPM method was also applied for Bi-2212/Ag PIT composite wire, and found to be very effective for improving the distribution of voids, which caused from the melt-solidifying process. The GPM showed a marked effect for obtaining homogeneous long wire. A 1 T class coil was successfully fabricated with monocore wire

Study of Beam Profile Measurement at Interaction Point in International Linear Collider

At the international linear collider, measurement of the beam profile at the interaction point is a key issue to achieve high luminosity. We report a simulation study on a new beam profile monitor, called the pair monitor, which uses the hit distribution of the electron-positron pairs generated at the interaction point. We obtained measurement accuracies of 5.1%, 10.0%, and 4.0% for the horizontal, vertical, and longitudinal beam size, respectively, for 50 bunch crossings.Comment: 13 pages, 8 figures, 2 table

Investigating the role of the Itoigawa-Shizuoka tectonic line towards the evolution of the Northern Fossa Magna rift basin

AbstractThe Itoigawa-Shizuoka tectonic line (ISTL) fault system is considered to have one of the highest probabilities for a major inland earthquake occurrence in the whole of Japan. It is a complex fault system with the dip directions of the local fault segments changing from north to south between an east-dipping low-angle thrust fault, a strike slip fault and a west-dipping thrust fault. The tectonic relations between the different parts of the fault system and the surrounding geological units are yet to be fully explained. This study aims to reveal the juncture of the northern and central parts of the ISTL and investigate its contribution towards the shaping of the Northern Fossa Magna rift basin. We conducted 3 deployments of 1 or 2 linear arrays of seismic stations across the central and northern ISTL regions and observed local micro-earthquakes for a period of 3 years. Each deployment recorded continuous waveform data for approximately 3 months. Using arrival times of 1193 local earthquakes, we jointly determined earthquake locations and a 3D velocity model, applying the tomography method. We were able to image the regional crustal structures from the surface to a depth of 20km with a spatial resolution of 5km. Subsequently, we used the obtained 3D velocity model to relocate the background local seismicity from 2003 to 2009. The juncture of the northern and central parts of the ISTL was well constrained by our results. The depth extension of the northern parts of the ISTL fault segments follows the bottom of the Miocene Northern Fossa Magna rift basin (NFM) and forms an east-dipping low-angle fault. In contrast, the central parts of the ISTL fault segments are estimated to lie along the eastern boundary of the Matsumoto basin forming an oblique strike slip fault (Fig. 1)

Improved forecasts of winter weather extremes over midlatitudes with extra Arctic observations

Recent cold winter extremes over Eurasia and North America have been considered to be a consequence of a warming Arctic. More accurate weather forecasts are required to reduce human and socioeconomic damages associated with severe winters. However, the sparse observing network over the Arctic brings errors in initializing a weather prediction model, which might impact accuracy of prediction results at midlatitudes. Here we show that additional Arctic radiosonde observations from the Norwegian young sea ICE cruise project 2015 drifting ice camps and existing land stations during winter improved forecast skill and reduced uncertainties of weather extremes at midlatitudes of the Northern Hemisphere. For two winter storms over East Asia and North America in February 2015, ensemble forecast experiments were performed with initial conditions taken from an ensemble atmospheric reanalysis in which the observation data were assimilated. The observations reduced errors in initial conditions in the upper troposphere over the Arctic region, yielding more precise prediction of the locations and strengths of upper troughs and surface synoptic disturbances. Errors and uncertainties of predicted upper troughs at midlatitudes would be brought with upper level high potential vorticity (PV) intruding southward from the observed Arctic region. This is because the PV contained a ‘‘signal’’ of the additional Arctic observations as it moved along an isentropic surface. This suggests that a coordinated sustainable Arctic observing network would be effective not only for regional weather services but also for reducing weather risks in locations distant from the Arctic