scholarly journals Random heterogeneity outperforms design in network synchronization

2021 ◽  
Vol 118 (21) ◽  
pp. e2024299118
Author(s):  
Yuanzhao Zhang ◽  
Jorge L. Ocampo-Espindola ◽  
István Z. Kiss ◽  
Adilson E. Motter
Keyword(s):  
Biological Systems ◽  
Network Dynamics ◽  
Random Parameter ◽  
Intrinsic Disorder ◽  
Multielectrode Array ◽  
Communication Delays ◽  
Network Synchronization ◽  
Oscillator Networks ◽  
Parameter Heterogeneity ◽  
Random Heterogeneity

A widely held assumption on network dynamics is that similar components are more likely to exhibit similar behavior than dissimilar ones and that generic differences among them are necessarily detrimental to synchronization. Here, we show that this assumption does not generally hold in oscillator networks when communication delays are present. We demonstrate, in particular, that random parameter heterogeneity among oscillators can consistently rescue the system from losing synchrony. This finding is supported by electrochemical-oscillator experiments performed on a multielectrode array network. Remarkably, at intermediate levels of heterogeneity, random mismatches are more effective in promoting synchronization than parameter assignments specifically designed to facilitate identical synchronization. Our results suggest that, rather than being eliminated or ignored, intrinsic disorder in technological and biological systems can be harnessed to help maintain coherence required for function.

scholarly journals Existence of physical measures in some excitation–inhibition networks*

Nonlinearity ◽  
2021 ◽  
Vol 35 (2) ◽  
pp. 889-915
Author(s):  
Matteo Tanzi ◽  
Lai-Sang Young
Keyword(s):  
Dynamical Systems ◽  
Lyapunov Exponents ◽  
Biological Networks ◽  
Large Time ◽  
Biological Systems ◽  
Network Dynamics ◽  
Network Models ◽  
The Other ◽  
Rigorous Analysis ◽  
Physical Measures

Abstract In this paper we present a rigorous analysis of a class of coupled dynamical systems in which two distinct types of components, one excitatory and the other inhibitory, interact with one another. These network models are finite in size but can be arbitrarily large. They are inspired by real biological networks, and possess features that are idealizations of those in biological systems. Individual components of the network are represented by simple, much studied dynamical systems. Complex dynamical patterns on the network level emerge as a result of the coupling among its constituent subsystems. Appealing to existing techniques in (nonuniform) hyperbolic theory, we study their Lyapunov exponents and entropy, and prove that large time network dynamics are governed by physical measures with the SRB property.

scholarly journals Entropic model of network dynamics of clocking network synchronization

2021 ◽  
Vol 2131 (4) ◽  
pp. 042089
Author(s):  
A K Kanaev ◽  
E V Oparin ◽  
E V Oparina
Keyword(s):  
Network Dynamics ◽  
Technical Condition ◽  
Main Task ◽  
Differential Entropy ◽  
Network Synchronization ◽  
Telecommunication System ◽  
Entropy Model ◽  
Telecommunication Services ◽  
Diagnostic Parameters ◽  
Network Equipment

Abstract The main task of the clocking network synchronization (CNS) network subsystem is the formation, transmission, distribution and delivery of synchronization signals to the telecommunication system (TCS) digital equipment for the purpose of its coordinated interaction. Indicators of the telecommunication services quality are inextricably linked with the indicators of the CNS network functioning quality, in this regard, the process of monitoring and managing the CNS network comes to the fore for the purpose of prompt detection of failures and their subsequent elimination. The article provides an overview of the main classes of CNS network equipment and their diagnostic parameters, and also indicates the significant influence of the CNS network functioning process on the entire TCS functioning. To assess the technical condition of the CNS network an approach using the entropy analysis of the diagnostic parameters of the CNS network elements is proposed. The entropy model of the network dynamics is obtained in CNS work, which can later be used to develop a methodology for monitoring the technical condition of the CNS network. Using this model, it is possible to estimate not only the differential entropy of each CNS network element, but also to estimate the differential entropy of the entire CNS network or a separate fragment of the CNS network. Differential entropy parameters reflect the technical state of the CNS network.

Transmission Electron Microscopy of Protein Macromolecules

1971 ◽  
Vol 29 ◽  
pp. 424-425
Author(s):  
Henry S. Slayter
Keyword(s):  
Biological Systems ◽  
Metal Vapor ◽  
Resolving Power ◽  
Electron Microscopic ◽  
Chemical Methods ◽  
Molecular Weights ◽  
The Past ◽  
Physical Chemical ◽  
Transmission Electron

Electron microscopic methods have been applied increasingly during the past fifteen years, to problems in structural molecular biology. Used in conjunction with physical chemical methods and/or Fourier methods of analysis, they constitute powerful tools for determining sizes, shapes and modes of aggregation of biopolymers with molecular weights greater than 50, 000. However, the application of the e.m. to the determination of very fine structure approaching the limit of instrumental resolving power in biological systems has not been productive, due to various difficulties such as the destructive effects of dehydration, damage to the specimen by the electron beam, and lack of adequate and specific contrast. One of the most satisfactory methods for contrasting individual macromolecules involves the deposition of heavy metal vapor upon the specimen. We have investigated this process, and present here what we believe to be the more important considerations for optimizing it. Results of the application of these methods to several biological systems including muscle proteins, fibrinogen, ribosomes and chromatin will be discussed.

Freeze-fracture cytochemistry: A goal set by Russell Steere in 1957

1993 ◽  
Vol 51 ◽  
pp. 60-61
Author(s):  
Nicholas J Severs
Keyword(s):  
Chemical Nature ◽  
Biological Systems ◽  
Freeze Fracture ◽  
Structural Components ◽  
Major Goal ◽  
Membrane Biology ◽  
Routine Application ◽  
The Future ◽  
Freeze Etching

In his pioneering demonstration of the potential of freeze-etching in biological systems, Russell Steere assessed the future promise and limitations of the technique with remarkable foresight. Item 2 in his list of inherent difficulties as they then stood stated “The chemical nature of the objects seen in the replica cannot be determined”. This defined a major goal for practitioners of freeze-fracture which, for more than a decade, seemed unattainable. It was not until the introduction of the label-fracture-etch technique in the early 1970s that the mould was broken, and not until the following decade that the full scope of modern freeze-fracture cytochemistry took shape. The culmination of these developments in the 1990s now equips the researcher with a set of effective techniques for routine application in cell and membrane biology.Freeze-fracture cytochemical techniques are all designed to provide information on the chemical nature of structural components revealed by freeze-fracture, but differ in how this is achieved, in precisely what type of information is obtained, and in which types of specimen can be studied.

Seeking to uncover biology's chemical roots

2019 ◽  
Vol 3 (5) ◽  
pp. 435-443 ◽  
Author(s):  
Addy Pross
Keyword(s):  
Environmental Changes ◽  
Biological Systems ◽  
Significant Development ◽  
The Road ◽  
Physical Chemical ◽  
Systems Chemistry ◽  
Biological World ◽  
Inanimate Matter ◽  
The Origin Of Life ◽  
Opening Up

Despite the considerable advances in molecular biology over the past several decades, the nature of the physical–chemical process by which inanimate matter become transformed into simplest life remains elusive. In this review, we describe recent advances in a relatively new area of chemistry, systems chemistry, which attempts to uncover the physical–chemical principles underlying that remarkable transformation. A significant development has been the discovery that within the space of chemical potentiality there exists a largely unexplored kinetic domain which could be termed dynamic kinetic chemistry. Our analysis suggests that all biological systems and associated sub-systems belong to this distinct domain, thereby facilitating the placement of biological systems within a coherent physical/chemical framework. That discovery offers new insights into the origin of life process, as well as opening the door toward the preparation of active materials able to self-heal, adapt to environmental changes, even communicate, mimicking what transpires routinely in the biological world. The road to simplest proto-life appears to be opening up.

Sign in / Sign up

Export Citation Format

Share Document