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Bootstrapping the empirical bounds on the variability of Sample Entropy in 24-hour ECG recordings for 1 hour segments

Zurek S., Grabowski W., Kosmider M., Jurga S., Guzik P., Piskorski J.

Journal of Applied Mathematics and Computational Mechanics

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2018

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Vol. 17, nr 2

105--113

EN

We investigate the variability of one of the most often used complexity measures in the analysis of the time series of RR intervals, i.e. Sample Entropy. The analysis is carried out for a dense matrix of possible r thresholds in 79 24h recordings, for segments consisting of 5000 consecutive beats, randomly selected from the whole recording. It is repeated for the same recordings in random order. This study is made possible by the novel NCM algorithm which is many orders of magnitude faster than the alternative approaches. We find that the bootstrapped standard errors for Sample entropy are large for RR intervals in physiological order compared to the standard errors for shuffled data which correspond to the maximum available entropy. This result indicates that Sample Entropy varies widely over the circadian period. This paper is purely methodological and no physiological interpretations are attempted.

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Structural and dynamic properties of water confined inside a single-walled carbon nanotube - Molecular dynamics study

Kosmider M., Sokol M., Dendzik Z., Gburski Z.

Materials Science Poland

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2005

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Vol. 23, No. 2

475--481

EN

Atomically detailed molecular dynamics simulation has been performed to study structural and dynamical properties of the cluster of water molecules (H2O)(80) confined inside an open-ended single-walled (10,10) carbon nanotube (SWNT). The structural and dynamical properties of the confined cluster have been compared with the analogous results for an unconfined cluster of water molecules.

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Interaction-induced depolarized light scattering spectra of exohedral complexes of Ne and Ar with fullerenes and nanotubes

Dendzik Z., Kosmider M., Dawid A., Kaczor K., Gburski Z.

Materials Science Poland

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2005

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Vol. 23, No. 2

457--466

EN

Recently, Dawid and Gburski (Phys. Rev. A, 68 ( 2003), 065202) have studied the molecular dynamics of a system consisting of a C-60 molecule surrounded by a monolayer argon film and determined the interaction induced polarizability correlation function and the depolarized light scattering spectra of this system. In the present work a number of exohedral complexes of Ar and Ne forming an ultrathin monolayer film physisorbed on a fullerene or nanotube surface have been studied.

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Dynamics of the exohedral complex composed of Ar atomic film adsorbed on the surface of single-walled carbon nanotube. Computer simulation study

Dendzik Z., Kosmider M., Palucha S., Brol P., Gburski Z.

Materials Science Poland

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2005

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Vol. 23, No. 2

467--473

EN

A molecular dynamics study of the monolayer Ar atomic film adsorbed on the outer surface of single - walled (10,10) carbon nanotube has been undertaken and the vibrational spectra of this system have been determined. It was found that vibrations of the atoms in the argon film considerably influence the low - frequency vibrational dynamics of the nanotube.