Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Levels of Complexity in Scale-Invariant Neural Signals   Many physical and physiological signals exhibit complex scale-invariant
features characterized by $1/f$ scaling and long-range power-law correlations,
suggesting a possibly common control mechanism. Specifically, it has been
suggested that dynamical processes influenced by inputs and feedback on
multiple time scales may be sufficient to give rise to $1/f$ scaling and scale
invariance. Two examples of physiologic signals that are the output of
hierarchical, multi-scale physiologic systems under neural control are the
human heartbeat and human gait. Here we show that while both cardiac interbeat
interval and gait interstride interval time series under healthy conditions
have comparable $1/f$ scaling, they still may belong to different complexity
classes. Our analysis of the magnitude series correlations and multifractal
scaling exponents of the fluctuations in these two signals demonstrates that in
contrast with the nonlinear multifractal behavior found in healthy heartbeat
dynamics, gait time series exhibit less complex, close to monofractal behavior
and a low degree of nonlinearity. These findings are of interest because they
underscore the limitations of traditional two-point correlation methods in
fully characterizing physiologic and physical dynamics. In addition, these
results suggest that different mechanisms of control may be responsible for
varying levels of complexity observed in physiological systems under neural
regulation and in physical systems that possess similar $1/f$ scaling.

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The categories of this paper are: hep-ph
3
The categories of this paper are: physics
13
The categories of this paper are: quant-ph
26
The categories of this paper are: bayes-an
20
The categories of this paper are: acc-phys
11
The categories of this paper are: hep-lat
31
The categories of this paper are: ao-sci
23
The categories of this paper are: solv-int
37
The categories of this paper are: supr-con
2
The categories of this paper are: math
29
The categories of this paper are: funct-an
22
The categories of this paper are: chao-dyn
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The categories of this paper are: stat
10
The categories of this paper are: q-bio
30
The categories of this paper are: q-alg
24
The categories of this paper are: dg-ga