Kaname Satoh

In Vivo Visualization of Subtle, Transient, and Local Activity of Astrocytes Using an Ultrasensitive Ca2+ Indicator

Astrocytes generate local calcium (Ca(2+)) signals that are thought to regulate their functions. Visualization of these signals in the intact brain requires an imaging method with high spatiotemporal resolution. Here, we describe such a method using transgenic mice expressing the ultrasensitive ratiometric Ca(2+) indicator yellow Cameleon-Nano 50 (YC-Nano50) in astrocytes. In these mice, we detected a unique pattern of Ca(2+) signals. These occur spontaneously, predominantly in astrocytic fine processes, but not the cell body. Upon sensory stimulation, astrocytes initially responded with Ca(2+) signals at fine processes, which then propagated to the cell body. These observations suggest that astrocytic fine processes function as a high-sensitivity detector of neuronal activities. Thus, the method provides a useful tool for studying the activity of astrocytes in brain physiology and pathology.

The tsunami of 3 February 1605

Whether the origins of the tsunami of 3 February 1605 were separated ones or a joined one, is one of the most important problems for Japanese society. When the marine knowledge has not been popularized, it has been considered that the damage pattern on Hachijo Island (including Kojima) was an important key to solving this question.It resembles the situation that the reports concerning the tsunami of 1 April 1946 were introduced to Japanese society under an internal disturbance just after the war, and we overlooked the most important consideration on the combination of tsunami and storm waves caused by the trade wind, and received this tsunami as an extraordinarily huge one.We studied the statistics of recent wind directions around Hachijo Island in January and February 1973, 1974, 1977, 1983, 1984, 1985, 1986 and 1987. And we believed that the probability was high that we could explain well that the damage pattern on Hachijo Island in 1605 was due to the combination of tsunami and storm waves caused by the monsoon.We need not, therefore, look back the damage pattern on Hachijo Island when we consider the fact that the necrologies of many temples in Shizuoka Prefecture record no death on 3 February 1605, proves to be the key to infer that the origins were separated ones.

Problems concerning the directivity of tsunami; application to the case of earthquake of 19 September 1985

AbstractIf knowledge of our theories on the directivity of tsunamis had received worldwide attention, the following operations could have been carried out internationally just after the large earthquake of 19 September 1985 which occurred near Acapulco, Mexico.Having found the great circle, “line S” which is perpendicular to the coast around Acapulco, we could have calculated the angles between line S and line A and between line S and line D, where line A and line D are the great circle connecting Acapulco and Auckland, New Zealand and that connecting Acapulco and Duke of York Island (Chile), respectively. The resultant angles are 30‡43′ and 41‡49′(>68‡48′/2), we could thereafter neglect the eastern half of the offshore energy flux.When we assume that the speed of trans-Pacific tsunami is 400 knots, the probability that the actual tsunami will come earlier than the calculated arrival time proves to be

WAVE SPECTRA AND HULL RESPONSE IN THE ACTUAL SEA STATES

\frac{1}{{\sqrt {2\pi } }}\int_{ - {\text{ }}\infty }^{ - {\text{ }}0.689} {e^{ - t^{{2 \mathord{\left/ {\vphantom {2 2}} \right. \kern-\nulldelimiterspace} 2}} } dt = 0.2454}

Field experiment on static characteristics of midwater trawl system.

Contact with New Zealand prior to the forecasted arrival time was essential, but the tsunami attention for the Japanese coast was unnecessary.Without such application of our directivity theories, frequent fruitless warnings will be issued for future trans-Pacific tsunamis. Quick improvements in warning procedures are required.

The corrosion resistance of tuna long-line fishing hook using fish monofilament.

To obtain the hull response of a fishing boat encountering ocean waves, it is necessary to understand the wave characteristics. For this purpose, the authors measured the wave height and hull response in the actual sea, the time series data was for 5,000 cases. The data was analyzed statistically. The maximum and minimum values of wave amplitudes divided by the standard deviation of surface elevation are nearly equal to the values estimated using Rayleigh distribution as well as double amplitudes. The same results were obtained for pitch and roll motions. It was confirmed that the values of the sagging condition were larger than the hogging condition in the same sea states. However, the analyzed values of the highest 1/100 wave amplitudes and the maximum and minimum pitch amplitudes from measured data are larger than the estimated Rayleigh distribution.

COASTING MANOEUVRABILITY OF SINGLE CPP EQUIPPED SHIP AND THE APPLICATION OF A NEW CPP CONTROLLER

It is through that theoretical wave spectra are not often fitted to actual wave spectra in sea states. For clarification of the hull response of a fishing boat encountering ocean waves, it is essential to measure and understand the real state of waves. The spectral analysis was made using time series data measured by a wave height meter, and the spectra were compared with the Modified Pierson-Moskowitz wave spectra (P-M type). The authors tried to clarify the relationship between the wave spectral form and hull response in the actual sea states, from the characteristic wave spectral form obtained form the results. Although the spectral form of ship motion derived from the characteristic wave spectra were different from the P-M type, there were small differences between the significant values of ship motion estimated from those wave spectra.

Tuna long-line tests using monofilament nylon.

The wave and hull response of a fishing vessel was measured over forty days with a hull response system and a wave height meter using micro doppler radar. The records were analysed and the distribution of extremes on hull response and the wave frequency table was shown. From the results, the observed values of a long-term distribution of extremes on hull response in ocean waves were compared to the theoretical values derived from the wave data. Using the distribution of wave direction, the observed values for ship motions are almost equal to the theoretical values. Further analysis of the characteristics of the response of the longitudinal bending stress and a through examination of the wave spectrum are necessary. See also abstract no. 91092154.