Initial results of Syowa MF radar observations in Antarctica

Observations of the neutral atmosphere from the mesosphere to the lower thermosphere were performed using the MF radar system that was installed at Syowa Station (69°S, 39°E), Antarctica in April 1999. The radar is equipped with four antennas and independent receivers and is able to conduct interferometric observations, such as meteor echo observations, in addition to observations based on conventional spaced antenna techniques. Observational parameters are carefully designed so that the same raw data can be processed using various analysis techniques, including correlation analyses, meteor echo analysis and electron density analysis. The radar equipment specifications and preliminary results of wind observations are presented

First observations of Polar Mesospheric Echoes at both 31MHz and 53.5MHz over Svalbard (78.2°N 15.1°E)

During summer 2020, observations of the mesosphere using a 53.5 MHz radar on Svalbard, at 78.2°N 15.1°E, revealed the well-known Polar Mesospheric Summer Echoes (PMSE). At the same time, a co-located meteor detection radar, operating at 31 MHz detected corresponding echoes very distinct from those associated with meteor trails. Comparing as many days as possible during 2020, incontestable evidence arose to demonstrate that the meteor detection radar was capable of observing PMSE, although not in the optimised fashion of the 53.5 MHz system. We present examples of results from both systems, supplementing the earlier findings of Swarnalingam et al. (2009), and simultaneously show very first results from this particular geographical location

Characteristics of the Terdiurnal tide in the MLT above Davis and Syowa

第3回極域科学シンポジウム　横断セッション「中層大気・熱圏」 11月26日（月） 国立極地研究所 ２階大会議

A new method for monitoring and removing SuperDARN radar DC offsets

DC offsets in quadrature outputs (I/Q signals) pertinent to the SuperDARN HF radars can cause problems in determining and analysing auto-correlation functions, cross-correlation functions and raw time series data if they are not negligible. We have developed a new code to monitor and remove DC offsets. To obtain correct DC offset levels and noise levels, the offsets can be best removed using I/Q signals during the receive-only period, i.e., during each clear frequency search stage. We have implemented the new code in the current radar operating system, installed it at the SENSU Syowa radars, and have been obtaining and removing DC offset values continuously since October 2001

On the histo-morphological changes of transplantable tumors.

1. When chicken sarcoma virus is serially inoculated on the mouse brain, it loses its carcinogenecity, but when it is inoculated on young chicken, granuloma develops in the liver and lung. When this granuloma is transplanted on adult chicken, a transplantable fibrosarcoma is obtained. 2. According to literature, the originaltumor of the Brown-Pearce cancer is a basal cell cancer, but that imported to Japan in 1953 presented a histological picture of carcinosarcoma. The metastasized tumor of the eye presents a purely cancer tissue, but when this is inoculated on the testis, carcinosarcoma is reproduced. It is therefore considered that the mother cell of the sarcoma is of host origin. 3. MY sarcoma is not a sarcoma, but is a spindle cell cancer. It might be a sarcoma which transformed into a cancer during serial transplantation, but perhaps it was originally a cancer but had been erroneously diagnosed as sarcoma. 4. The tumors we obtained by means of the feeding tests of Yoshida tumor all developed at organs other than those of the digestive tract. They are chiefly reticulo-sarcoma, but others which develop are malignant granuloma in the liver and lung, malignant adenoma in the kidney, papilloma of pelvis, and ependymoma in the cerebral ventricle. Since the discovery of the Yoshida tumor in 1943, serial transplantation has been conducted for 19 years with this tumor not only in Japan but also in foreign countries, but there has been no report to this date that a transformed strain has developed by cell transplantation. It therefore must be considered that the carcinogenesis observed in our feeding tests is a carcinogenesis due to a mechanism completely unlike that of cell transplantation. It has been confirmed by electron microscopy that in the early stage of transplantation of this tumor into the abdominal cavity there was an additional tumor growth due to the anaplastic proliferation of serous cells. 5. During the serial transplantation of viral tumors and/or virus dependent tumors, the tumor sometimes undergoes a morphological change. Though the cause of this is not yet sufficiently elucidated, it is suspected that there is some relationship with virus in the wide sense.</p

ダイナミックアセスメントのための隠れマルコフIRTモデル

教育の最も難しい問題は，教師は学習者に教えすぎても，教えなさすぎても学習者の十分な発達は望めないということである．そのために，教師は個々の学習者の理解度や最適な支援の度合いを予測することが重要な課題となっている．足場がけによる学習者のパフォーマンスを予測するために，項目反応理論を用いて最適な予測正答確率になるようにヒントを提示する足場がけシステムが開発されている．しかし，従来の項目反応理論では，学習者の能力変化がモデルに考慮されておらず，正確な正答確率を予測できないために，最適なヒント数を予測できていない可能性がある．本研究では，学習者の能力が時間変化していくプロセスを項目反応理論に組み込み，能力が隠れマルコフ過程に従って変化すると仮定した新しい項目反応モデルを提案する．提案モデルでは，能力値が継続する時間(課題数) を表すウィンドウサイズと能力の変動の程度を反映する変動パラメータをもち，これらの最適値がデータから推定されるために，学習者の真の能力変化を反映でき，予測精度を向上させることが期待される．実データを用いて，本提案の有効性を示す．To scaffold a learner efficiently, a teacher should predict the optimal degree of assistance to support learner\u27s development. However, conventional Item Response Theory (IRT) model does not consider learner\u27s ability changes during his/her studying, therefore the IRT model might cause over-assistance or lack of assistance. We propose a new IRT model that incorporates learner\u27s ability change according to a Hidden Markov process. The proposed model has the following two new parameters: the degree of the ability changes and the period of time that the learner\u27s ability does not change. The experiments result shows that the proposed model improves the prediction accuracy of learner\u27s performances

Ion temperature and velocity variations in the D- and E-region polar ionosphere during stratospheric sudden warming

The Tenth Symposium on Polar Science/Ordinary sessions: [OS] Space and upper atmospheric sciences, Wed. 4 Dec. /Entrance Hall (1st floor) at National Institute of Polar Research (NIPR

Mesospheric anomalous diffusion during noctilucent clouds

The Andenes specular meteor radar shows meteor-trail diffusion rates increasing on average by ~ 20% at times and locations where a lidar observes noctilucent clouds (NLCs). This high-latitude effect has been attributed to the presence of charged NLC but this study shows that such behaviors result predominantly from thermal tides. To make this claim, the current study evaluates data from three stations, at high-, mid-, and low-latitudes, for the years 2012 to 2016, comparing diffusion to show that thermal tides correlate strongly with the presence of NLCs. This data also shows that the connection between meteor-trail diffusion and thermal tide occurs at all altitudes in the mesosphere, while the NLC influence exists only at high-latitudes and at around peak of NLC layer. This paper discusses a number of possible explanations for changes in the regions with NLCs and leans towards the hypothesis that relative abundance of background electron density plays the leading role. A more accurate model of the meteor trail diffusion around NLC particles would help researchers determine mesospheric temperature and neutral density profiles from meteor radars.Public versio