Environmental change based on diatom assemblages from Lake Yamanaka at the northern foot of Mt, Fuji, Central Japan

Environmental history in Lake Yamanaka was investigated based on diatom assemblages obtained from the 17.5m length borehole core in the lake center. Lake Yamanaka (surface area 6.89km²; maximun depth 14.3m; mean depth 9.4m; altitude above sea level 978m) is one of the Fuji Five Lakes and located at the northern foot of Mt.Fuji. Although this lake had been considered formed by the lava flow from Mt.Fuji about 1850 years ago, results of this research suggested that the formation age more old stage on account of the presence of planktonic diatoms mentioned below. The borehole core sample has mainly consists of unconsolidated silts and scoria fall deposits associated with sandstone layers. According to the composition of diatoms contained in silts, the geohistory of this lake was divided into 4 periods;i.e., 1) The 1'st swamp or river period (11.4-9.2m borehole core in depth); Epiphytic or benthic diatomes such as Flagiralia spp. or Epithemia sp. were dominant in these samples. 2) The 1'st lake period(9.2-6.0m borehole core in depth): Planktonic diatoms such as Aulacoseira sp. or Cyclotella sp. were dominant in these samples. 3) The 2'nd swamp or very shallow lake period(6.0-2.5m borehole core in depth): Epiphytic or benthic diatoms became dominant again. 4) The 2'nd lake period (2.5m-surface borehole core): Planktonic diatoms were dominant again.Article信州大学山地水環境教育研究センター研究報告 2: 105-110(2004)departmental bulletin pape

Cryogenic measurement of the optical absorption coefficient in sapphire crystals at 1.064(micro)m for the Large-scale Cryogenic Gravitational wave Telescope

We have applied laser calorimetry to the measurement of optical absorption in mono-crystalline sapphire at cryogenic temperatures. Sapphire is a promising candidate for the mirror substrates of the Large-scale Cryogenic Gravitational wave Telescope. The optical absorption coefficients of different sapphire samples at a wavelength of 1.064(micro)m at 5K were found to average 90ppm/cm.Comment: 8 pages, accepted to Phys. Lett.

Direct Measurement of Thermal Fluctuation of High-Q Pendulum

We achieved for the first time a direct measurement of the thermal fluctuation of a pendulum in an off-resonant region using a laser interferometric gravitational wave detector. These measurements have been well identified for over one decade by an agreement with a theoretical prediction, which was derived by a fluctuation-dissipation theorem. Thermal fluctuation is dominated by the contribution of resistances in coil-magnet actuator circuits. When we tuned these resistances, the noise spectrum also changed according to a theoretical prediction. The measured thermal noise level corresponds to a high quality factor on the order of 10^5 of the pendulum.Comment: 10 pages, 4 figure

Mark Tracking: Position/orientation measurements using 4-circle mark and its tracking experiments

Future space robots require position and orientation tracking with visual feedback control to track and capture floating objects and satellites. We developed a four-circle mark that is useful for this purpose. With this mark, four geometric center positions as feature points can be extracted from the mark by simple image processing. We also developed a position and orientation measurement method that uses the four feature points in our mark. The mark gave good enough image measurement accuracy to let space robots approach and contact objects. A visual feedback control system using this mark enabled a robot arm to track a target object accurately. The control system was able to tolerate a time delay of 2 seconds

The Effects of Font Type on Reading Accuracy and Fluency in Japanese Children with Developmental Dyslexia

We administered rapid reading tasks in Japanese children (32 with typical development and 24 with developmental dyslexia), and investigated the effects of two different font types: Rounded-Gothic and Mincho style font. In the experiment, we used four kinds of stimuli: two scripts (paragraphs and random kana character non-words) in two font types (Rounded-Gothic and Mincho style font). In this experiment, the duration time, the number of errors and the number of self-corrections were measured during reading. Participants were asked which font type was easier to read. There was no significant difference in the duration time, the number of errors and the number of self-corrections between two types of fonts among the 56 participants. On the other hand, regarding subjective readability, the developmental dyslexia group reported that the Rounded-Gothic font was easier to read. There was a difference between objective and subjective readability. In this study, there was no difference in reading performance of Rounded-Gothic and Mincho style fonts in Japanese children with developmental dyslexia

A marker tephra bed close to the Lower-Middle Pleistocene boundary: Distribution of the Ontake-Byakubi Tephra Bed in central Japan

Tephrochronology is an exceptionally important tool in the precise regional correlation of Early and Middle Pleistocene sedimentary strata in Japan. The present study reveals that the Yukawa tephra 5 (YUT5) derived from the Older Ontake volcano, the Nezumigawa (Nzg) and Mitamitajima (Mtj) tephras of the Ina Bazin, and the Byakubi-E tephra (Byk-E) of the Boso Peninsula are the same tephra on the basis of their lithofacies, bulk grain composition, mafic mineral composition, major element composition of hornblende, and stratigraphic relationships with the dated tephras. We propose to call the series of tephras correlated with Byk-E the Ontake-Byakubi Tephra Bed (On-Byk Tephra) following the naming convention in which the tephra name consists of the names of the source volcano and the type location. The Matuyama-Brunhes Chronozone boundary occurs just above Byk-E in the type section of the Kokumoto Formation in the Kazusa Group, which is a candidate Global Boundary Stratotype Section and Point (GSSP) for the lower boundary of the Middle Pleistocene Subseries. Therefore, On-Byk Tephra becomes a critically important marker tephra bed for the Early-Middle Pleistocene boundary in central Japan. The present study indicates that the major element composition of hornblende can be a useful tool for identification and correlation of strongly weathered tephra layers such as Nzg and Mtj in which all the volcanic glass shards have been altered.ArticleQuaternary International. 397: 27-38(2016)journal articl

シリョウ ショガイコク ノ テツドウ サンギョウ ニオケル キギョウ シュウダン ケイエイ タカクカ ニカンスル ジョウキョウ

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