This work studies the stability and the stochastic properties of neural activity evoked by external stimulation. The underlying nonlocal model describes the spatiotemporal response dynamics of neural populations involving both synaptic delay and axonal transmission delay. We show that the linear model recasts to a set of affine delay differential equations in spatial Fourier space. Besides a st...

A basic measure of an oscillator’s performance is its frequency stability (or instability depending on one’s point of view). In the long term (timescales of days or years), we refer to frequency changes as aging. On moderate timescales (seconds), the stability of an oscillator is often characterized in terms of its Allan variance [1]. On short timescales (usually less than one second), frequenc...

Environmental fluctuations can generate asynchronous species' fluctuations and community stability, due to compensatory dynamics of species with different environmental tolerances. We tested this hypothesis in intertidal hard-bottom communities of north-central Chile, where a persistent upwelling centre maintains a mosaic in sea surface temperatures (SST) over 10s of kilometres along the shore....

'Animal personalities' have been shown to exist in many species. Yet, fluctuations in the stability of these inter-individual behavioural differences are not well understood. Against this background, we wondered whether behavioural consistency over time is affected by the reproductive cycle. Female mice were tested twice at an interval of eight weeks in four paradigms assessing social interest ...

Controller adaptation is always a major concern. A controller that meets certain performance design objectives can not be satisfactory unless it can preserve such quality in the presence of system parameters fluctuation. For the nuclear power reactors (NPR) a controller that preserves stability and performance for wide range of operation conditions and fluctuations is especially desirable. This...

We study the dynamical stability of pulse coupled networks of leaky integrateand-fire neurons against infinitesimal and finite perturbations. In particular, we compare current versus fluctuations driven networks, the former (latter) is realized by considering purely excitatory (inhibitory) sparse neural circuits. In the excitatory case the instabilities of the system can be completely captured ...

We investigate the effects of random noise on network systems. In particular, we consider a simple class of growing network models whose topological structure is determined by the preferred attachment A(k). We introduce a noise-induced attachment A(k) which includes fluctuations in the number of links of individual nodes due to a random noise. We carry out the numerical simulations to show that...

Abs t rac t . Contrary to the common sense in economics and financial engineering, price fluctuations at very fine level of motion exhibit various evidences against the efficient market hypothesis. We attempt to investigate this issue by studying extensive amount of foreign currency exchange data for over five years at the finest level of resolution. We specifically focus on the proposed stabil...

A two dimensional model is introduced to study pattern formation, secondary instabilities and the transition to spatiotemporal chaos (weak turbulence) in parametric surface waves. The stability of a periodic standing wave state above onset is studied against Eckhaus, zig-zag and transverse amplitude modulations (TAM) as a function of the control parameter ε and the detuning. A mechanism leading...