Statistical Modeling of Subjective Sleep Quality.

Effective maintenance/improvement of sleep quality requires knowledge of how sleep quality is connected to quantitative features of sleep and arbitrarily selected habitual lifestyles, which naturally depend on the demographic characteristics of individuals. To fulfill these needs, a regression model of subjective sleep quality was constructed, whereby one might be able to design a practical strategy for achieving comfortable sleep adapted to individual conditions. Based on data obtained from our previous study, fundamental correlation profiles between day-to-day subjective and quantitative features of sleep were estimated. Obtained correlation profiles involving SRSs, quantitative features of sleep, and sleep habits across a week such as bedtime preference (chronotype), discrepancy between chronotype and social time cue (social jetlag), and habitual sleep-wake pattern (HSWP) were characterized specifically for each self-ratings of sleep quality (SRS) category through backward stepwise Linear Mixed Effect (LME) modeling. The LME model represented SRSs with acceptable accuracy, allowing identification of determinant factors for each category of SRS. The SRS is one possible option to clarify sleep status. In this study, we proposed a possible framework including model-based predictors of SRS in which self-awareness of sleep quality could be improved to facilitate healthy sleep practices.

Relationship between Dynamics of Physiological Signals and Subjective Quality of Life and Its Lifestyle Dependency.

In terms of preventive healthcare, how adopted lifestyle maintains healthy states or leads to pathological states is an essential issue. In this study, for the healthy subjects, their daily patterns of heart rate variability (HRV) and behavioral activity dynamics were analyzed in association with subjective quality of life (QOL), and how the relationship between the physiological signal dynamics and QOL is differentiated by the chronotype (sleep-wake pattern) was investigated. As a result, the morning type subjects were found to show higher sequential variation in R-R interval (rMSSD) and behavioral activity, and to have higher sleep quality and non-depressive tendency. Even the evening type subjects could have higher sleep quality under the condition that rMSSD shows a dip around early afternoon and keep a higher level of activity during the daytime, which may be due to realization of steady entrainment to the circadian time cues. Through this study, fundamental knowledge for preventive healthcare was obtained for us to help people's choice of an appropriate lifestyle for their health.

An efficient screening approach for anti-Microcystis compounds based on knowledge of aquatic microbial ecosystem.

To improve the efficiency of screening for anti-Microcystis compounds, we planned to use algae-lysing bacteria that kill the organisms of water blooms. A two step-screening process was carried out, i.e., the screening of algae-lysing bacteria and the selection of anti-Microcystis producers from the bacteria. Sources for the isolation of the bacteria were a co-cultivated fluid of a water sample with axenic Microcystis viridis, a water sample collected in a water bloom season, and a water bloom sample. The water bloom sample was the best source for the isolation of the algae-lysing bacteria and such bacteria were shown to exhibit potent activity. Seventeen strains out of 20 isolated algae-lysing bacteria produced anti-Microcystis activities, and one of the principles was the previously reported argimicin A. These results indicate that algae-lysing bacteria in water blooms may be good sources for potent and selective anticyanobacterial compounds.

Real-time memory on an excitable field.

Recently, we proposed a novel method for computing logic operations based on the time-sequential information in a geometrically arranged excitable field. As an extension of this study, in the present article we describe a strategy for creating real-time memory. Using a numerical simulation, we show that input pulse trains can be stored as a sequence of rotating traveling waves in a circular excitable field, by using its characteristics as a diode due to spatially asymmetric arrangement. Furthermore, through an experiment on an excitable chemical reaction, we demonstrate that this real-time memory actually works in the real world.

Information operations with an excitable field.

It is well established that a traveling wave can be generated on an excitable field, which is described with a pair of partial differential equations for an activator and inhibitor. In the present paper, we use a numerical simulation to show that the traveling wave, or signaling pulse, can be transmitted from an excitable field to an opposing excitable field via an intervening passive diffusion field in a characteristic manner depending on the spatial geometry of the excitable fields. Using such characteristics, it is possible to design various kinds of logic gates together with a time-sequential memory device. Thus, these functions can perform time-sensitive operations in the absence of any controlling clock. It may be possible to accomplish these computations with excitable fields in an actual system, or to create a "field computer" composed of electronic active and passive units.