LONG-RANGE CORRELATIONS IN THE PHASE-SHIFTS OF NUMERICAL SIMULATIONS OF BIOCHEMICAL OSCILLATIONS AND IN EXPERIMENTAL CARDIAC RHYTHMS

1999 ◽  
Vol 07 (02) ◽  
pp. 113-130 ◽  
Author(s):  
I. M. DE LA FUENTE ◽  
L. MARTINEZ ◽  
J. M. AGUIRREGABIRIA ◽  
J. VEGUILLAS ◽  
M. IRIARTE
Keyword(s):  
Phase Shift ◽  
Periodic Solutions ◽  
Long Range ◽  
Phase Shifts ◽  
Long Range Correlations ◽  
Rescaled Range ◽  
Biochemical Oscillations ◽  
Phase Shift Data ◽  
Relationship Of ◽  
The Relationship

In biochemical dynamical systems during each transition between periodical behaviors, all metabolic intermediaries of the system oscillate with the same frequency but with different phase-shifts. We have studied the behavior of phase-shift records obtained from random transitions between periodic solutions of a biochemical dynamical system. The phase-shift data were analyzed by means of Hurst's rescaled range method (introduced by Mandelbrot and Wallis). The results show the existence of persistent behavior: each value of the phase-shift depends not only on the recent transitions, but also on previous ones. In this paper, the different kind of periodic solutions were determined by different small values of the control parameter. It was assessed the significance of this results through extensive Monte Carlo simulations as well as quantifying the long-range correlations. We have also applied this type of analysis on cardiac rhythms, showing a clear persistent behavior. The relationship of the results with the cellular persistence phenomena conditioned by the past, widely evidenced in experimental observations, is discussed.

scholarly journals DETRENDED FLUCTUATION ANALYSIS OF AUTOREGRESSIVE PROCESSES

2007 ◽  
Vol 07 (03) ◽  
pp. L249-L255 ◽  
Author(s):  
VASILE V. MORARIU ◽  
LUIZA BUIMAGA-IARINCA ◽  
CĂLIN VAMOŞ ◽  
ŞTEFAN M. ŞOLTUZ
Keyword(s):  
Long Range ◽  
Detrended Fluctuation Analysis ◽  
Short Range ◽  
Interaction Constant ◽  
Fluctuation Analysis ◽  
Autoregressive Processes ◽  
Long Range Correlations ◽  
Correlation Exponent ◽  
The Relationship ◽  
Detrended Fluctuation

Autoregressive processes (AR) have typical short-range memory. Detrended Fluctuation Analysis (DFA) was basically designed to reveal long-range correlations in non stationary processes. However DFA can also be regarded as a suitable method to investigate both long-range and short-range correlations in non stationary and stationary systems. Applying DFA to AR processes can help understanding the non-uniform correlation structure of such processes. We systematically investigated a first order autoregressive model AR(1) by DFA and established the relationship between the interaction constant of AR(1) and the DFA correlation exponent. The higher the interaction constant the higher is the short-range correlation exponent. They are exponentially related. The investigation was extended to AR(2) processes. The presence of an interaction between distant terms with characteristic time constant in the series, in addition to a near by interaction will increase the correlation exponent and the range of correlation while the effect of a distant negative interaction will significantly decrease the range of interaction, only. This analysis demonstrate the possibility to identify an AR(1) model in an unknown DFA plot or to distinguish between AR(1) and AR(2) models.

scholarly journals Alterations to the remote control of Shh gene expression cause congenital abnormalities

2013 ◽  
Vol 368 (1620) ◽  
pp. 20120357 ◽  
Author(s):  
Robert E. Hill ◽  
Laura A. Lettice
Keyword(s):  
Long Range ◽  
Congenital Abnormalities ◽  
Limb Bud ◽  
Temporal Expression ◽  
Developmentally Regulated ◽  
Conserved Sequence ◽  
Regulatory Mutations ◽  
Spatio Temporal ◽  
Relationship Of ◽  
The Relationship

Multi-species conserved non-coding elements occur in the vertebrate genome and are clustered in the vicinity of developmentally regulated genes. Many are known to act as cis -regulators of transcription and may reside at long distances from the genes they regulate. However, the relationship of conserved sequence to encoded regulatory information and indeed, the mechanism by which these contribute to long-range transcriptional regulation is not well understood. The ZRS, a highly conserved cis -regulator, is a paradigm for such long-range gene regulation. The ZRS acts over approximately 1 Mb to control spatio-temporal expression of Shh in the limb bud and mutations within it result in a number of limb abnormalities, including polydactyly, tibial hypoplasia and syndactyly. We describe the activity of this developmental regulator and discuss a number of mechanisms by which regulatory mutations in this enhancer function to cause congenital abnormalities.

Probing the Relationship of Long-Range Order in Nanodomain FeCo Alloys with Ternary Additions Using Neutron Diffraction

2009 ◽  
Vol 41 (5) ◽  
pp. 1144-1150 ◽  
Author(s):  
Ralph Gilles ◽  
Michael Hofmann ◽  
Yan Gao ◽  
Frank Johnson ◽  
Luana Iorio ◽  
...  
Keyword(s):  
Neutron Diffraction ◽  
Long Range ◽  
Range Order ◽  
Long Range Order ◽  
Feco Alloys ◽  
Ternary Additions ◽  
Relationship Of ◽  
The Relationship

Solution of the Bethe–Goldstone Equation in Finite Nuclei from N–N Phase Shift Data

1972 ◽  
Vol 50 (9) ◽  
pp. 940-946
Author(s):  
R. J. W. Hodgson
Keyword(s):  
Wave Function ◽  
Phase Shift ◽  
Harmonic Oscillator ◽  
Shell Model ◽  
Phase Shifts ◽  
Matrix Elements ◽  
Pauli Operator ◽  
Phase Shift Data ◽  
Finite Nuclei ◽  
Shift Data

An approach is outlined wherein the Bethe–Goldstone wave function may be computed in a shell-model basis from a knowledge of the harmonic-oscillator matrix elements. These in turn may be derived from the N–N phase shifts by a number of different methods. The Pauli operator is treated exactly in the space of two-particle shell-model states. The method is applied to a calculation of the levels of 18O and 18F and results obtained using different two-body matrix elements are compared.

scholarly journals Interactions of Positrons and Electrons with Hydrogenic Systems, Excitation, Resonances, and Photoabsorption in Two-Electron Systems

2020 ◽  
Author(s):  
Anand K. Bhatia
Keyword(s):  
Long Range ◽  
Cross Sections ◽  
Phase Shifts ◽  
Electron Systems ◽  
Positron Impact ◽  
Matrix Formulation ◽  
Close Coupling ◽  
R Matrix ◽  
Long Range Correlations ◽  
Approaches To Study

There are a number of approaches to study interactions of positrons and electrons with hydrogenic targets. Among the most commonly used are the method of polarized orbital, the close-coupling approximation, and the R-matrix formulation. The last two approaches take into account the short-range and long-range correlations. The method of polarized orbital takes into account only long-range correlations but is not variationally correct. This method has recently been modified to take into account both types of correlations and is variationally correct. It has been applied to calculate phase shifts of scattering from hydrogenic systems like H, He+, and Li2+. The phase shifts obtained using this method have lower bounds to the exact phase shifts and agree with those obtained using other approaches. This approach has also been applied to calculate resonance parameters in two-electron systems obtaining results which agree with those obtained using the Feshbach projection-operator formalism. Furthermore this method has been employed to calculate photodetachment and photoionization of two-electron systems, obtaining very accurate cross sections which agree with the experimental results. Photodetachment cross sections are particularly useful in the study of the opacity of the sun. Recently, excitation of the atomic hydrogen by electron impact and also by positron impact has been studied by this method.

scholarly journals Fractal Tempo Fluctuation and Pulse Prediction

2009 ◽  
Vol 26 (5) ◽  
pp. 401-413 ◽  
Author(s):  
Summer K. Rankin ◽  
Edward W. Large ◽  
Philip W. Fink
Keyword(s):  
Long Range ◽  
Music Performance ◽  
Superior Performance ◽  
Fractal Scaling ◽  
Long Range Correlations ◽  
Rescaled Range ◽  
Interval Time Series ◽  
Serial Correlations ◽  
Tempo Fluctuations ◽  
Natural Expression

WE INVESTIGATED PEOPLES' ABILITY TO ADAPT TO THE fluctuating tempi of music performance. In Experiment 1, four pieces from different musical styles were chosen, and performances were recorded from a skilled pianist who was instructed to play with natural expression. Spectral and rescaled range analyses on interbeat interval time-series revealed long-range (1/f type) serial correlations and fractal scaling in each piece. Stimuli for Experiment 2 included two of the performances from Experiment 1, with mechanical versions serving as controls. Participants tapped the beat at ¼¼- and ⅛⅛-note metrical levels, successfully adapting to large tempo fluctuations in both performances. Participants predicted the structured tempo fluctuations, with superior performance at the ¼¼-note level. Thus, listeners may exploit long-range correlations and fractal scaling to predict tempo changes in music.

Preliminary research on the relationship between long-range correlations and predictability

2011 ◽  
Vol 20 (1) ◽  
pp. 019201 ◽  
Author(s):  
Zhi-Sen Zhang ◽  
Zhi-Qiang Gong ◽  
Rong Zhi ◽  
Guo-Lin Feng ◽  
Jing-Guo Hu
Keyword(s):  
Long Range ◽  
Long Range Correlations ◽  
Preliminary Research ◽  
The Relationship

Return Intervals Analysis of the Sunspot Time Series

2010 ◽  
Vol 29-32 ◽  
pp. 1144-1149
Author(s):  
Jie Fan ◽  
Wan Qing Li ◽  
Hong Zhang ◽  
Ke Qiang Dong
Keyword(s):  
Time Series ◽  
Long Range ◽  
Threshold Values ◽  
Range Analysis ◽  
Scaling Method ◽  
Long Range Correlations ◽  
Rescaled Range ◽  
Rescaled Range Analysis

Rescaled range analysis (R/S) method is a scaling method commonly used for detecting the long-range correlations in many time series. The aim of this paper is to show that, using the rescaled range analysis on sunspot time series, how the threshold values q affects the correlations of the return intervals for events above a certain threshold q. We find that both the original records and the return intervals are long-range correlated.

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