Estimation of Body Structure by Biomechanical Impedance

In the stiffness evaluation from the skin surface, the body structure under the skin, like a bone and muscle, influences on the measurement results. The authors developed the measurement system of biomechanical impedance with applying a vibration of acoustic frequency onto the body surface. We measured the viscoelasticity of the silicone-gel model, which involves metal blocks, from the gel surface by using this system. The internal structure of model is estimated from the relation between the viscoelasticity and the distance from the gel surface to the internal block. Applying this method, the shape of ribs of the right chest are estimated. The shapes and viscoelasticity of silicone-gel tumor model, which has two different tumors, are also estimated

Topographic Organization of Projections from the Amygdala to the Hypothalamus of the Rat

Afferent fibers from the amygdala to subdivisions of lateral, ventromedial and dorsomedial hypothalamic nuclei were investigated in rat by retrograde transport of horseradish peroxidase. Small (intranuclear size) peroxidase deposits were placed in hypothalamic nuclei by iontophoresis of a tracer solution containing poly-L-α-ornithine which greatly limited diffusion. The medial, central and amygdalo-hippocampal nuclei of the amygdala were found to be the major donors of amygdaloid afferent fibers to the hypothalamus, but there was also substantial labeling of somata in cortical, basomedial, basolateral and lateral amygdaloid nuclei and the intra-amygdaloid bed nucleus of the stria terminalis. No fibers projected from the posterior cortical nucleus of the amygdala to the hypothalamus. Most amygdaloid projections to the lateral hypothalamic area originated in the anterior half of the amygdala, while projections to the ventromedial hypothalamic nucleus arose along the entire length of the amygdala except the posterior cortical nucleus. The amygdalo-hippocampal area projects to the medial hypothalamus. Other amygdaloid nuclei project to both the medial and lateral hypothalamic nuclei. These topographic organizations of amygdaloid afferent fibers to various subdivisions of the hypothalamic nuclei are discussed and compared with other anatomical studies on these connections

Bio-mimetic Control of Mobile Robots Based on a Model of Bacterial Chemotaxis

This paper proposes a new control method of mobile robots based on a model of bacterial chemotaxis including not only intracellular information processing but also motor control on the basis of the molecular evidence. E. coli is chosen as a target bacterium, which has a simple molecular structure and is amenable to biochemical and genetic analysis. First, a computer model of the chmotaxis is developed to simulate its emergence. Parameters included in the model are regulated using the genetic algorithm in such a way that a fitness representing the chemotactic ability is maximized. Then, using a mobile robot incorporated this chemotactic model, experiments of trajectory generation are preformed, and it is confirmed that the mobile robot can be controlled based on the bacterial model

Experiments on meteor burst communications in the Antarctic

Two kinds of experiments on the meteor burst communication(MBC) are now being conducted in the Antarctic to study the ability of MBC as a communication medium for data collection systems in that region. In the first one, continuous tone signal is transmitted from Zhongshan Station. The received signal at Syowa Station about 1400km apart is recorded and analyzed. This experiment is to study basic properties of the meteor burst channel in that high latitude region. From the data available thus far, we can see that 1) the sinusoidal daily variation in the meteor activity typical in mid and low latitude regions can not be clearly seen, 2) non-meteoric propagations frequently dominate the channel, etc. On the other hand, the second experiment is to estimate data throughput of a commercial MBC system in that region. A remote station at Zhongshan Station tries to transfer data packets each consists of 10 data words to the master station at Syowa Station. Data packets are generated with five min interval. We are now operating the system only five min in each ten min interval. About 60% of the generated data packets are constantly transferred to the master station within two hours delay

VHF data transmission experiments using MBC equipment conducted during the period from JARE-43 to JARE-45

In order to study the ability of meteor burst communications (MBC) as a new medium of data collection networks in Antarctica, we have performed a series of VHF data transmission experiments. In the experiment during the period of JARE-43 (the 43rd Japanese Antarctic Research Expedition), a remote station at Zhongshan Station sent data packets to a master station at Syowa Station using a commercial MBC system. Together with meteor burst propagations, non-meteoric propagations were frequently observed during local nighttime. We found that they worked effectively for packet transmissions and greatly increased the data throughput. Overall data throughput obtained by this experiment was 0.63bps. In JARE-44, we added another remote station at Dome Fuji Station. Since the transmitted power from the master unit was split into two directions, data throughput from Zhongshan Station was reduced to 0.36bps. That from Dome Fuji Station was only 0.13bps. For the experiment in JARE-45, we replaced the commercial MBC system with a RANDOM (RAdio Network for Data Over Meteor) system developed by the authors. The experiment is being conducted between Syowa and Zhongshan Stations. The estimated data throughput during the period from April 1st, 2004 to August 31st, 2004 was 2.9bps

The Iwasawa λ-invariants of ℤₚ-extensions of real quadratic fields

1. Introduction. Let k be a totally real number field. Let p be a fixed prime number and ℤₚ the ring of all p-adic integers. We denote by λ=λₚ(k), μ=μₚ(k) and ν=νₚ(k) the Iwasawa invariants of the cyclotomic ℤₚ-extension $k_∞$ of k for p (cf. [10]). Then Greenberg's conjecture states that both λₚ(k) and μₚ(k) always vanish (cf. [8]). In other words, the order of the p-primary part of the ideal class group of kₙ remains bounded as n tends to infinity, where kₙ is the nth layer of $k_∞//k$. We know by the Ferrero-Washington theorem (cf. [2], [15]) that μₚ(k) always vanishes when k is an abelian (not necessarily totally real) number field. However, the conjecture remains unsolved up to now except for some special cases (cf. [1], [3], [5]-[8], [13]). This paper is a continuation of our previous papers [3], [5]-[7] and [12], that is to say, we investigate Greenberg's conjecture when k is a real quadratic field and p is an odd prime number which splits in k. The purpose of this paper is to extend our previous results, and to give basic numerical data of k=ℚ(√m) for 0 ≤ m ≤ 10000 and p=3. On the basis of these data, we can verify Greenberg's conjecture for most of these k's