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Takashi Kanamaru
In this study, I considered quantifying the strength of chaos in the population firing rate of a pulse-coupled neural network. In particular, I considered the dynamics where the population firing rate is chaotic and the firing of each neuron is stochastic. I calculated a time histogram of firings to show the variation in the population firing rate over time. To smooth this histogram, I used Bayesian adaptive regression splines and a gaussian filter. The nonlinear prediction method, based on reconstruction, was applied to a sequence of interpeak intervals in the smoothed time histogram of firings...
December 8, 2017: Neural Computation
Svetoslav Nikolov, Guido Santos, Olaf Wolkenhauer, Julio Vera
Mathematical modeling of cell differentiated in colonic crypts can contribute to a better understanding of basic mechanisms underlying colonic tissue organization, but also its deregulation during carcinogenesis and tumor progression. Here, we combined bifurcation analysis to assess the effect that time delay has in the complex interplay of stem cells and semi-differentiated cells at the niche of colonic crypts, and systematic model perturbation and simulation to find model-based phenotypes linked to cancer progression...
December 7, 2017: Bulletin of Mathematical Biology
Maxim V Petoukhov, Anne Tuukkanen
Small angle scattering of X-rays (SAXS) and neutrons (SANS) is a structural technique to study disordered systems with chaotic orientations of scattering inhomogeneities at low resolution. An important example of such systems are solutions of biological macromolecules. Rapid development in the methodology for solution scattering data interpretation and model building during the last two decades brought the analysis far beyond the determination of just few overall structural parameters (which was the only possibility in the past) and ensured SAS a firm position in the methods palette of the modern life sciences...
2017: Advances in Experimental Medicine and Biology
Olusegun Steven Ayodele Oluwole
El Niño southern oscillation (ENSO) dynamics has been shown to drive seasonal influenza dynamics. Severe seasonal influenza epidemics and the 2009-2010 pandemic were coincident with chaotic regime of ENSO dynamics. ENSO dynamics from 1876 to 2016 were characterized to determine if influenza pandemics are coupled to chaotic regimes. Time-varying spectra of southern oscillation index (SOI) and sea surface temperature (SST) were compared. SOI and SST were decomposed to components using the algorithm of noise-assisted multivariate empirical mode decomposition...
2017: Frontiers in Public Health
Enid Van Nieuwenhuyse, Gunnar Seemann, Alexander V Panfilov, Nele Vandersickel
Early Afterdepolarizations, EADs, are defined as the reversal of the action potential before completion of the repolarization phase, which can result in ectopic beats. However, the series of mechanisms of EADs leading to these ectopic beats and related cardiac arrhythmias are not well understood. Therefore, we aimed to investigate the influence of this single cell behavior on the whole heart level. For this study we used a modified version of the Ten Tusscher-Panfilov model of human ventricular cells (TP06) which we implemented in a 3D ventricle model including realistic fiber orientations...
2017: PloS One
Yanping Xu, Ping Lu, Stephen Mihailov, Xiaoyi Bao
We demonstrate for the first time, to the best of our knowledge, a high-speed physical random bit generator at gigabits/second without the time-delay signature based on chaotic power fluctuations of a random fiber laser. The random fiber laser is configured using a ring structure with semiconductor optical amplifiers as the optical gain and a fiber random grating as the random feedback medium. The long-length ring cavity provides a large number of densely spaced cavity modes that co-exist within the gain bandwidth tailored by the optical filter...
December 1, 2017: Optics Letters
Amanda Landers, Rachel Wiseman, Suzanne Pitama, Lutz Beckert
Patients with severe chronic obstructive pulmonary disease (COPD) have a chaotic trajectory towards death. Research has focused on identifying a "transition point" that would allow identification of those patients who may benefit from a palliative approach to their care, or referral to a specialist palliative care service. This article aims to outline difficulties in identifying this transition point, summarise current literature on this topic and suggests a model based on clinical milestones. Educational aims: To outline the difficulties associated with identifying patients with severe COPD who are at risk of dying...
December 2017: Breathe
Tsung-Hung Lin, Chen-Kun Tsung, Tian-Fu Lee, Zeng-Bo Wang
The security is a critical issue for business purposes. For example, the cloud meeting must consider strong security to maintain the communication privacy. Considering the scenario with cloud meeting, we apply extended chaotic map to present passwordless group authentication key agreement, termed as Passwordless Group Authentication Key Agreement (PL-GAKA). PL-GAKA improves the computation efficiency for the simple group password-based authenticated key agreement (SGPAKE) proposed by Lee et al. in terms of computing the session key...
December 3, 2017: Sensors
Maria Vittoria Caruso, Raffaele Serra, Paolo Perri, Gianluca Buffone, Francesco Giuseppe Caliò, Stefano DE Franciscis, Fragomeni Fragomeni
PURPOSE: Hemodynamics has a key role in atheropathogenesis. Indeed, atherosclerotic phenomena occur in vessels characterized by complex geometry and flow pattern, like the carotid bifurcation. Moreover, lifestyle is a significant risk factor. The aim of this study is to evaluate the hemodynamic effects due to two sedentary lifestyles - sitting and standing positions - in the carotid bifurcation in order to identify the worst condition and to investigate the atherosclerosis incidence. METHODS: The computational fluid dynamics (CFD) was chosen to carry out the analysis, in which in vivo non-invasive measurements were used as boundary conditions...
2017: Acta of Bioengineering and Biomechanics
Adam Ponzi
Implicit expectations induced by predictable stimuli sequences affect neuronal response to upcoming stimuli at both single cell and neural population levels. Temporally regular sensory streams also phase entrain ongoing low frequency brain oscillations but how and why this happens is unknown. Here we investigate how random recurrent neural networks without plasticity respond to stimuli streams containing oddballs. We found the neuronal correlates of sensory stream adaptation emerge if networks generate chaotic oscillations which can be phase entrained by stimulus streams...
December 4, 2017: Scientific Reports
T M Khlebodarova, V V Kogai, E A Trifonova, V A Likhoshvai
The mammalian target of rapamycin (mTOR) signaling pathway is the central regulator of cap-dependent translation at the synapse. Disturbances in mTOR pathway have been associated with several neurological diseases, such as autism and epilepsy. RNA-binding protein FMRP, a negative regulator of translation initiation, is one of the key components of the local translation system. Activation and inactivation of FMRP occurs via phosphorylation by S6 kinase and dephosphorylation by PP2A phosphatase, respectively...
December 5, 2017: Molecular Psychiatry
John McCamley, William Denton, Elizabeth Lyden, Jennifer M Yentes
The aim of this investigation was to compare and contrast the use of cross sample entropy (xSE) and cross recurrence quantification analysis (cRQA) measures for the assessment of coupling of rhythmical patterns. Measures were assessed using simulated signals with regular, chaotic, and random fluctuations in frequency, amplitude, and a combination of both. Biological data were studied as models of normal and abnormal locomotor-respiratory coupling. Nine signal types were generated for seven frequency ratios...
2017: Computational and Mathematical Methods in Medicine
Sebabrata Mukherjee, Dmitri Mogilevtsev, Gregory Ya Slepyan, Thomas H Doherty, Robert R Thomson, Natalia Korolkova
A photonic circuit is generally described as a structure in which light propagates by unitary exchange and transfers reversibly between channels. In contrast, the term 'diffusive' is more akin to a chaotic propagation in scattering media, where light is driven out of coherence towards a thermal mixture. Based on the dynamics of open quantum systems, the combination of these two opposites can result in novel techniques for coherent light control. The crucial feature of these photonic structures is dissipative coupling between modes, via an interaction with a common reservoir...
December 4, 2017: Nature Communications
Jonathan Yaari, Dorota Gruber, Andrew D Blaufox
OBJECTIVE: We hypothesize that routine daily transtelephonic monitoring (TTM) transmissions can accurately detect supraventricular tachycardia (SVT) in asymptomatic infants and/or assuage parental concerns rather than being used solely to diagnose arrhythmias. STUDY DESIGN: Single center, retrospective chart review of 60 patients with fetal or infant SVT prescribed TTM for at least 30 days, January 2010-September 2016. Patients were excluded if initial SVT was not documented, was perioperative, was atrial flutter/fibrillation, or chaotic atrial tachycardia...
November 30, 2017: Journal of Pediatrics
Elisa Giupponi, Roberta Visone, Paola Occhetta, Federica Colombo, Marco Rasponi, Gabriele Candiani
The grail of gene delivery is the development of delivery vectors as effective and non-cytotoxic as possible. In this regard, there is an urgent need of new tools for the straightforward and quantitative assessment of transfection efficiency and cytotoxicity simultaneously. We herein reported the development and validation of an easy-to-use lab-on-chip platform to perform cell transfection assays for unbiased, high-throughput selection of more and more effective gene delivery vectors by using 2 commercially sourced lipids, Lipofectamine 2000® and FuGene® 6...
December 2, 2017: Biotechnology and Bioengineering
Jérémy Oden, Roman Lavrov, Yanne K Chembo, Laurent Larger
We propose a chaos communication scheme based on a chaotic optical phase carrier generated with an optoelectronic oscillator with nonlinear time-delay feedback. The system includes a dedicated non-local nonlinearity, which is a customized three-wave imbalanced interferometer. This particular feature increases the complexity of the chaotic waveform and thus the security of the transmitted information, as these interferometers are characterized by four independent parameters which are part of the secret key for the chaos encryption scheme...
November 2017: Chaos
Pavel Buran, Markus Bär, Sergio Alonso, Thomas Niedermayer
Electrical turbulence in cardiac tissue is associated with arrhythmias such as life-threatening ventricular fibrillation. Recent experimental studies have shown that a sequence of low-energy electrical far-field pulses is able to terminate fibrillation more gently than a single high-energy pulse which causes severe side effects. During this low-energy antifibrillation pacing (LEAP), only tissue near sufficiently large conduction heterogeneities, such as large coronary arteries, is activated. In order to optimize LEAP, we performed extensive simulations of cardiac tissue perforated by blood vessels, employing two alternative cellular models that exhibit electrical turbulence at a similar length scale...
November 2017: Chaos
Eugene A Ryzhov
The nonlinear dynamics of an elliptic vortex subjected to a time-periodic linear external shear flow is studied numerically. Making use of the ideas from the theory of nonlinear resonance overlaps, the study focuses on the appearance of chaotic regimes in the ellipse dynamics. When the superimposed flow is stationary, two general types of the steady-state phase portrait are considered: one that features a homoclinic separatrix delineating bounded and unbounded phase trajectories and one without a separatrix (all the phase trajectories are bounded in a periodic domain)...
November 2017: Chaos
Sulimon Sattari, Kevin A Mitchell
Transport properties of chaotic systems are computable from data extracted from periodic orbits. Given a sufficient number of periodic orbits, the escape rate can be computed using the spectral determinant, a function that incorporates the eigenvalues and periods of periodic orbits. The escape rate computed from periodic orbits converges to the true value as more and more periodic orbits are included. Escape from a given region of phase space can be computed by considering only periodic orbits that lie within the region...
November 2017: Chaos
Anshul Choudhary, Chiranjit Mitra, Vivek Kohar, Sudeshna Sinha, Jürgen Kurths
We report the phenomenon of temporally intermittently synchronized and desynchronized dynamics in Watts-Strogatz networks of chaotic Rössler oscillators. We consider topologies for which the master stability function (MSF) predicts stable synchronized behaviour, as the rewiring probability (p) is tuned from 0 to 1. MSF essentially utilizes the largest non-zero Lyapunov exponent transversal to the synchronization manifold in making stability considerations, thereby ignoring the other Lyapunov exponents. However, for an N-node networked dynamical system, we observe that the difference in its Lyapunov spectra (corresponding to the N - 1 directions transversal to the synchronization manifold) is crucial and serves as an indicator of the presence of intermittently synchronized behaviour...
November 2017: Chaos
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