8,067 research outputs found
Visualization of Minute Mechanical-Excitation/Relaxation Wave-front Propagation in Myocardial Tissue
Unlike the case of skeletal muscle, the direction of myocardial contraction does not coincide with the direction of work necessary to eject the intraventricular blood, contributing to great complexity of the wall deformation sequence of cardiac contraction. The advent of advanced techniques (CT^1^, MRI^2,3^, SPECT^4^, echocardiology^5-9^, electrocardiography^10^, and magnetocardiography^11,12^) has enabled to the evaluation of cardiac function and disorders by the measurement of blood flow, pressure, electrical reaction process, and other factors. However, complexity of the contraction sequence is still not fully understood because the dynamic mechanical excitation process, which directly correlates with contraction, cannot be accurately measured based on these electro-magnetic phenomena. Here, developing and using a noninvasive novel imaging modality with high temporal and spatial resolutions^13-17^, we show that the propagation of the mechanical wave-front occurs at the beginning of each cardiac contraction and relaxation sequence for the first time. The former occurs about 60 ms prior to the ordinarily accepted onset time of the contraction (R-wave of the electrocardiogram). From the apical side of the interventricular septum, close to the terminal of the Purkinje fibers (specialized to carry contraction impulses), a minute velocity component with an amplitude of several tenth micrometers is generated and propagates sequentially to the entire left ventricle, that is, it propagates from the apex to the base of the posterior wall, and then from the base to the apex of the septum, with a propagation speed of 3-9 m/s. The latter occurs at the end of the first heart sound at the apical side and propagates to the base side with a speed of 0.6 m/s. These physiological findings, unlike the widely accepted myocardial excitation process, have potential for accurate assessment of myocardial tissue damage in coronary disease and cardiomyopathy. This dynamic measurement modality is also applicable to various tissues in biology
Demand for Currency, New Technology and the Adoption of Electronic Money: Evidence Using Individual Household Data
Accurate information on money demand is essential for evaluation of monetary policy. In this regard, it is important to study the effect of financial innovation to money demand. We investigate the effect of a new form of such technology, electronic money, to money demand. Specifically, we estimate currency demand functions conditional on electronic money adoption using unique household-level survey data from Japan. We obtain the following results. First, currency demand indicates that average cash balances do not decrease with the adoption of electronic money. Rather, it seems to increase under some specifications. Second, households at the lowest quantile of the cash balance distribution tend to have higher cash balances after adopting of electronic money. These findings indicate that consumers do not significantly substitute cash holding with e-money holding despite the rapid diffusion of electronic money among households.Currency Demand, Transaction Demands for Money, Electronic Money
A Viable System Model Reinforced by Meta Program Management
AbstractThe global markets are embroidered by profound complexity woven by the persistent worldwide economic recession, the EURO crisis and shift of economic powers as well as escalating competition among traditional and emerging suppliers of hard products. Many companies with hard products are facing their eroding competitiveness as they base their corporate value on excellent, yet locked-in hard capabilities. Especially, the Japanese leading electronics companies have reported shaky business performances in business year 2011 while other Japanese companies with systems products are performing well over the Japanese industry average. Against these rugged performances of the Japanese companies, a natural question arises as to what makes such a difference now among those in the same manufacturing industry which used to be generally performing well in a line; whether an enterprise viability system problem exists with the troubled companies; and what are solutions that project and program management can contribute to in the complex market environment as now. This paper configures a resilient enterprise system model in the Japanese “monodukuri” industry, or, the industry of manufacturing and systems environment integration, which would enable companies to consistently cope with changing environment and produce corporate value out of ecosystem adaptation and systems integration capabilities on the foundation of meta program management
Theoretical Analysis of Solar Thermal Collector with a Flat Plate Bottom Booster Reflector
A theoretical analysis of a solar thermal collector with a flat plate bottom reflector is presented. The bottom reflector extends from the lower edge of the collector. The variations of daily solar radiation absorbed on the collector with inclinations from horizontal for both the collector and reflector throughout the year were predicted, and the optimum inclinations of the collector and reflector which maximize the daily solar radiation absorbed on the collector were determined for each month at 30oN latitude. The effects of the size of the collector and reflector on the daily solar radiation absorbed on the collector were also investigated. The optimum collector inclination is lower in summer and higher in winter, while the optimum reflector inclination is higher in summer and lower in winter. The average daily solar radiation absorbed on the collector throughout the year can be increased about 20%, 27% and 33% by using a bottom reflector if the ratio of reflector length to collector length is 0.5, 1.0 and 2.0, respectively, when the collector’s length is equal to its width. Key words: Solar energy; Solar thermal collector; Bottom reflector; Collector-reflector; Optimum inclinatio
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