Quantification of PERF 15 mRNA in Tissue Sections from Rat Testes

We previously conducted basic research to quantify in situ hybridization (ISH) signals in rat testes. In this experimental model, we selected ribosomal RNA (rRNA) as the hybridizable RNA in paraffin sections, since it allowed us to easily analyze ISH signals expressed with digoxygenin (DIG)-labeled probes quantitatively through “posterization” of the images. We applied this method to analyze the quantification of transcript, PERF 15 mRNA. PERF 15 is expressed specifically in the testes and localized in the rigid cytoskeletal structure of the sperm head, and has been considered to be involved in the apoptotic process of spermatogenic cells. Quantification of the signals may help to clarify the detailed function of PERF 15. We further analyzed the signals concomitant with a confocal laser scanning microscope. The peak of PERF 15 mRNA expression was found in diplotene spermatocytes, and the amount of PERF 15 mRNA was greatest in late pachytene and diplotene spermatocytes and early spermatids, followed by early pachytene spermatocytes, and then late spermatids. PERF 15 may be involved in the events leading to meiotic division, in which apoptosis is also involved. The present study may help to determine the concentration of mRNA in tissue sections

Chapter 26 – Active Monitoring Using Submarine Cables—Leveraging Offshore Cabled Observatory for Passive Monitoring

Eight seafloor are observatories installed in Japanese water. Passive monitoring by these observatories has revealed a number of qualities that include detailed micro-earthquake activity before and after plate-boundary earthquakes, the existence of micro-tsunamis, the capability of early detection of tsunamis, the importance of seafloor geodetic observations, etc. These new findings were brought about by passive, real-time and continuous time series of earthquake and tsunami records acquired on the seafloor. Recently, our knowledge about earthquake source mechanisms has revealed the possibility of the detection of spatiotemporal changes in physical properties that may occur at inter-plate boundaries, and active seismic surveys have found reflection amplitude differences at seismically inactive plate boundaries or possible seismic asperities. We propose that the detection of such physical property changes becomes possible when we combine seafloor observations and active seismic sources dedicated to the precise monitoring of reflection amplitudes at plate boundary interfaces

Time Code Reader for Ocean Bottom Seismometer using Microprocessor and Its Application for New Data Processing

A time code reader for ocean bottom seismometer (OBS) using a microprocessor was developed. A serial time code is converted from analog to digital from. The serial digital code is transformed to parallel data. The code is decoded to BCD code and is displayed on CRT. Using the time code reader, a new playback method which drastically reduces the processing time to one tenth of the former one is proposed. The new playback system needs only one transcription for the playback of the OBS original tape

Hypocenter Distribution in the Japan Trench Region, off Sanriku, Northeast Japan, Determined by an Ocean-Bottom Seismometer Array Observation

An OBS array observation (seven stations and one month) was. performed in June and July, 1981 off-Sanriku, Japan Trench region, Northeast Japan. The array covered the area of both the island-arc side and the ocean basin side of the trench axis. In order to improve the resolution capability of focal depth estimation, we developed a new earthquake location algorithm, which is characterized by a ray initializer technique for the three-dimensional heterogeneous velocity structure, an addition of the origin time constraint in the least-squareiteration procedure, and another addition of an examining procedure for the effect of the initial trial-focal-depth. Three distinct groups. were revealed in the hypocenter distribution in the Japan Trench region. (1) One group is a long and narrow zonal distribution along the bathymetric contour of a depth of about 6km in the outer-slope region. The depths of these earthquakes are shallow within the ocean crust. They appear to correspond to the graben structures in this region representing the bending motion of the ocean crust. (2) Another group is the earthquakes in clusters near the trench axis in the outer-slope region. The depths of these earthquakes extend deep into the uppermost mantle beneath the Moho discontinuity from the shallow crust along a nearly vertical plane representing a lithospheric faulting motion. This place corresponds to the locatin of the main shock of the 1933 large off-Sanriku earthquake. This seismicity appears to be associated with the subsidence and a sharp bending de formation of the subducting ocean crust under the inner-slope region after crossing the trech axis. (3) The third group is the swarm earthquakes in the inner-slope region at a water depth of 2-3km. The depths of these earthquakes are nearly at the interface between. the overlying landside rock mass and the underlying ocean crust. This seismic activity would represent either a slip or a thrust faulting motion along the interface.海底地震計群列観測を,1981年夏,三陸沖日本海溝域において行い,7観測点で,6月11日から7月12日に至る33日間の同時観測のデータを得た.群列観測網は海溝軸を挟んで海盆側と島弧側と両方に設けた.震源深度の分解能を高めるために,新しく震源決定アルゴリズムを開発した.それは(1)3次元不均質構造を取扱うRay Initializerを用いたこと,(2)最小二乗法反復手順に震源発震時に対する拘束条件を加えたこと,(3)初期試行震源深度の影響を吟味する手順を加えたことなどに特徴づけられる.その結果,日本海溝域の震源分布について,3つの群が見出された.それらの特徴は次の通りである.(1)1つの群は日本海溝外側斜面域において水深約6kmの等深線に沿って,長くかつ狭い幅の線状傾向を示す帯状分布である.これらの地震の震源深度は浅く,海洋地殻内に起っている.これらは海溝外側斜面域に発達する地溝構造に対応しているようであり,海洋地殻の曲げ変形運動を表わしているものと思われる.(2)2つめの群は海溝軸の近傍,外側斜面下に房状のまとまりを示す地震である.その場所は1933年三陸沖大地震(M=8.3)の主震の震央に対応している.これらの地震の震源深度は深く,海洋地殻からモホ面下,最上部マントル内部約45kmにわたって起つており,その分布はほぼ垂直に近い面に沿っており,海洋リソスフィヤの断層運動を示しているようである.この最上部マントル内の地震活動は海溝軸を越えて海溝内側斜面下へ沈み込む海洋地殻の鋭い曲げ変形と沈降とに関連しているもののようである.(3)3つめの群は海溝内側斜面下水深2-3kmの地域に起った群発地震である.これらの地震の震源深度は海洋地殻と上盤の陸側岩体との境界付近にあたっている.この地震活動は境界面に沿うすべり或は断層運動を表わしているものであろう

有限要素法を使って求めた断層形成に伴う地殻変形

Crustal deformations associated with fault formation are calculated by the finite element method. Four dip angles are considered : (1) vertical ; (2) 45 degrees ; (3) 26.7 degrees ; and (4) horizontal. A low elasticity area is hypothesized as a fault zone. Sets of double couple forces are applied for a fault. Effects due to several variables (boundary condition, fault thickness, fault length and fault depth) are examined, and surface deformations are calculated. Boundary conditions affect the magnitude of surface deformation ; depth, length and thickness of a fault affect not only the magnitude, but also the pattern of deformation. For two cases, displacement field and stress field are shown. Using comparisons of the above crustal deformations and field data in the Mikawa earthquake of 1945 (M=7.1), a best-fit model for fault parameters is obtained. The model is in fairly good agreement with that obtained by Ando\u27s dislocation model

25. An Application of the Adaptive Differential PCM(ADPCM) Method to the Seismic Wave Signal Compression

We have examined the Adaptive Differential Pulse Code Modulation (ADPCM) method which has been used for a digital speech synthesis on compressing seismic wave data. Response of the ADPCM for the seismic wave data was examined not only by hardlogic which used the speech analyzer but also by software which used the FORTRAN programs. The results indicate that the ADPCM is practically useful for seismic wave data, with the compression ratio ranging from one-third without filtering to one-forth with filtering.地震波信号をディジタル化することにより波形精度が向上することは言うまでもないが,それと共にディジタルデータを伝送する回線及び収納する媒体の容量の増大化は著しく,データの圧縮が要求される.これまで地震波信号の伝送等に用いられている対数圧縮は簡単ではあるが波形の再現性はあまり良くない.データ圧縮の技術は音声合成法の発展により急速に進歩しつつあり,種々の方法が試みられている,多くの圧縮法のなかでも,ADPCM(適応差分PCM)法は圧縮度はPARCOR法,アダマール・ウォルシュ変換に比べ高くないが,地震波信号を扱う場合に最も重要な波形の再現性は高い.ADPCM法は波形信号そのものを数値化するものではなく,前のデータ値との差(増加又は減少分)だけを数値化したものを最適化し,効率の良い変換を行う方法である.ADPCM用CMOS-IC(OKI-MSM-5218)評価用機器を用いてADPCM法による地震波信号を圧縮する試みを行った,また,FORTRANプログラムによるソフトウエアからの検討も行った.実験は堂平微小地震観測所,及び海底地震計で観測された地震波信号を12bit,200Hzでサンブリソグしたデータを3bit(1/4圧縮),及び4bit(1/3圧縮)に圧縮伸張を施した.その結果,4bitにっいては通常の地震波信号はほぼ忠実に再現され,3bitについてもノイズ除去のためのフィルターを併用すれば地震波信号の伝送・収録に充分実用出来る事が確認出来た

P-wave Velocity Structure of Lithosphere-asthenosphere beneath the Western Northwest Pacific Basin Determined by an Ocean-bottom Seismometer Array Observation

A P-wave velocity-depth structure was studied in the western North-west Pacific Basin by making a composite record section using six earthquakes which covered the epicentral distances from 6° to 18°. Assuming an uppermost mantle layer of 8.0 km/sec at a depth of 13 km, depths of the velocity boundaries of 8.3 km/sec and 8.4 km/sec were determined at about 61km and 132 km respectively. The depth of the low-velocity layer which forms the shadow zone of P-wave refraction beyond 15° was estimated at about 149 km. This low-velocity layer could be regarded as the major transition from the lithosphere to the asthenosphere. The thickness of the lithosphere in the western Northwest Pacific Basin is thicker than formerly reported.前報に引続き,北西太平洋海盆にて得られた海底地震計長距離群列観測のデータから,同海域のP波速度構造を求めた.先づ震央距離6°～18°にわたる走時記録断面を6ヶの地震を用いて作成した(第2図).震源における発震時の誤差の補正は走時曲線の基準となる直線をずらして合わせるという方法を用いた.幸い,1981年7月9日10時28分,M=4.5(JMA)の地震が起り,その震源データが震源付近に展開してあった群列によって精度よく求められた.それによってリソスフィヤからの屈折波の原点走時が決まり,各速度層の深度が決まった.見掛け速度8.4km/s,8.6kmIsの深度がそれぞれ約61km,132kmと求められた.15°以遠の影領域(Shadow zone)を作る低速度層の深度の推定は波線経路の断面を作ることによって行った.その結果,15°以遠に入るべき波線の最深点から,低速度層の深度は約149kmと推定された.勿論この深度は速度勾配に依存するので,更に詳しいことは波形振幅の距離による変化特性を調べねばならない.この深度は従来表面波の研究から求められている値より幾分大きめである