**Author details**

Toru Yazawa

this study. As a result, our time series obtained from any subjects are a 100% accurate. It is a perfectly captured R-R interval data: prematured ventricular contractions, atrial fibrillations,

mDFA computes SI values. For a given time series data, mDFA returns only one SI. If you repeat this procedure for a given time series, you get an exactly the same SI value. Readers can imagine an artificial time series that is, for example, a white noise-like fluctuation data, it gives a scaling exponent of 0.5. A random-walk-like time series data give a scaling exponent of 1.5. However, 1/f time series (SI = 1.0) is very difficult to make artificially, definitely because 1/f-spectrum-like fluctuation is an outcome from natural dynamic phenomena. In short, a

The uncertainty derives from the uncertainty of BioMedicine. The problem to be solved is how we interpret the meaning of SI. We agree that it could be a controversial issue for the people who read this article without doing experiments. Diagnosis/interpretation of data is

I recall my childhood: cicadas sing during the day of sunny summer days. It is like under perfect condition they sing. At night, I hear insects most of them were a cricket or a katydid. Whenever 'a boy of a curious nature' tried to capture them, he experienced, the insects stop singing if he

A few people have asked me if lobsters/crabs feel stress. My answer is 'yes' although there is a problem regarding the uncertainty and accuracy (see earlier text). The truth is not known yet, because animals never tell us how they feel. But they indeed sense a human. At least, the truth

We can explain that SI measure is like temperature measure (Celsius, C degree). SI has a criterion value as temperature does. If C is 37°, our healthiness is fine as far as temperature is of concern. In the same way, if SI is one (1.0), healthiness is fine. 1/f is comparable to SI = 1. It has been shown by Kobayashi and Musha in 1982 [1] and Peng et al. in 1990s [2, 3]. In those days, when Kobayashi et al. worked, their computer never had enough power to quickly calculate/

In short, the scaling exponent (SI) is accurate. The uncertainty derives from our interpretation. For our guide line, believe it or not, you may have no problem for the heart if you have SI,

This study suggests that the scaling exponents (SI) computed by mDFA can quantify stress. Furthermore, mDFA results were intriguing: cardiac muscle injury can be detected using mDFA. An ischaemic heart has a high SI. Before these findings, we already have proven in

animal models that injured crustacean hearts exhibited a high exponent [4, 5].

approached too closer to them. Typically, animals do not love human approaching.

that we found is SI changes when they sense a human (**Figures 7** and **9**).

structure of a time series gives a single SI. It is mathematically accurate.

never perfect, but SI calculation is accurate and perfect.

whatever it is.

20 Time Series Analysis and Applications

**7.2. Biology/medicine**

handle the time series data.

ranging 0.8 < SI < 1.2.

**8. Conclusion**

Address all correspondence to: yazawa-tohru@tmu.ac.jp

Biological Science, Tokyo Metropolitan University, Hachioji, Tokyo, Japan
