1,370 research outputs found
Traveling Wave Solutions of a Reaction-Diffusion Equation with State-Dependent Delay
This paper is concerned with the traveling wave solutions of a
reaction-diffusion equation with state-dependent delay. When the birth function
is monotone, the existence and nonexistence of monotone traveling wave
solutions are established. When the birth function is not monotone, the minimal
wave speed of nontrivial traveling wave solutions is obtained. The results are
proved by the construction of upper and lower solutions and application of the
fixed point theorem
Existence of global attractor for a nonautonomous state-dependent delay differential equation of neuronal type
The analysis of the long-term behavior of the mathematical model of a neural
network constitutes a suitable framework to develop new tools for the dynamical
description of nonautonomous state-dependent delay equations (SDDEs).
The concept of global
attractor is given, and some results which establish properties ensuring
its existence and providing a description of its shape, are proved.
Conditions for the exponential stability of the global attractor
are also studied. Some properties
of comparison of solutions constitute a key in
the proof of the main results, introducing methods of monotonicity
in the dynamical analysis of nonautonomous SDDEs.
Numerical simulations of some illustrative models show
the applicability of the theory.Ministerio de Economía y Competitividad / FEDER, MTM2015-66330-PMinisterio de Ciencia, Innovación y Universidades, RTI2018-096523-B-I00European Commission, H2020-MSCA-ITN-201
Chaotic dynamics in the Volterra predator-prey model via linked twist maps
We prove the existence of infinitely many periodic solutions and complicated
dynamics, due to the presence of a topological horseshoe, for the classical
Volterra predator--prey model with a periodic harvesting. The proof relies on
some recent results about chaotic planar maps combined with the study of
geometric features which are typical of linked twist maps.Comment: 24 pages, 4 figure
Recent developments in dynamical systems: three perspectives
This paper aims to an present account of some problems considered in the past years in Dynamical Systems, new research directions and also provide some open problems
Switchable Genetic Oscillator Operating in Quasi-Stable Mode
Ring topologies of repressing genes have qualitatively different long-term
dynamics if the number of genes is odd (they oscillate) or even (they exhibit
bistability). However, these attractors may not fully explain the observed
behavior in transient and stochastic environments such as the cell. We show
here that even repressilators possess quasi-stable, travelling-wave periodic
solutions that are reachable, long-lived and robust to parameter changes. These
solutions underlie the sustained oscillations observed in even rings in the
stochastic regime, even if these circuits are expected to behave as switches.
The existence of such solutions can also be exploited for control purposes:
operation of the system around the quasi-stable orbit allows us to turn on and
off the oscillations reliably and on demand. We illustrate these ideas with a
simple protocol based on optical interference that can induce oscillations
robustly both in the stochastic and deterministic regimes.Comment: 24 pages, 5 main figure
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