Noise-induced chaos: a conditioned random dynamics perspective

We consider transitions to chaos in random dynamical systems induced by an increase of noise amplitude. We show how the emergence of chaos (indicated by a positive Lyapunov exponent) in a logistic map with bounded additive noise can be analysed in the framework of conditioned random dynamics through expected escape times and conditioned Lyapunov exponents for a compartmental model representing the competition between contracting and expanding behaviour. We find that the noise-induced transition to chaos is caused by a rapid decay of the expected escape time from the contracting compartment, while all other order parameters remain approximately constant.Comment: 6 pages, 6 figure

Modelling Functional Shifts in Two-Species Hypercycles

Research on hypercycles focuses on cooperative interactions among replicating species, including the emergence of catalytic parasites and catalytic shortcircuits. Further interactions may be expected to arise in cooperative systems. For instance, molecular replicators are subject to mutational processes and ecological species to behavioural shifts due to environmental and ecological changes. Such changes could involve switches from cooperative to antagonistic interactions, in what we call a functional shift. In this article, we investigate a model for a two-member hypercycle model, considering that one species performs a functional shift. First, we introduce the model dynamics without functional shifts to illustrate the dynamics only considering obligate and facultative cooperation. Then, two more cases maintaining cross-catalysis are considered: (i) a model describing the dynamics of ribozymes where a fraction of the population of one replicator degrades the other molecular species while the other fraction still receives catalytic aid; and (ii) a system in which a given fraction of the population predates on the cooperating species while the rest of the population still receives aid. We have characterized the key bifurcation parameters determining extinction, survival, and coexistence of species. We show that predation, regardless of the fraction that benefits from it, does not significantly change dynamics with respect to the degradative case (i), thus conserving dynamics and bifurcations. Their biological significance is interpreted, and their potential implications for the dynamics of early replicators and ecological species are outlined

Novel sensing algorithm for linear read-out of bimodal waveguide interferometric biosensors

Altres ajuts: the ICN2 was supported by the CERCA programme of the Generalitat de Catalunya.Biosensors employing photonics integrated circuits, and specifically those that rely on interferometric evanescent wave working principles, have outstanding performances due to the extreme sensitivity exhibited in one-step and direct assay, without the need of amplification. Within the interferometric configurations, the Bimodal Waveguide (BiMW) interferometric sensor stands out due to its demonstrated sensitivity for real-life applications and the simplicity of its design. To overcome the ambiguities that arise from the periodic nature of interferometric read-outs, a new all-optical modulation and the subsequent trigonometry-based algorithm have been proposed and applied to the BiMW biosensor. This new algorithm has been successfully employed for the selective identification and quantification of the external Spike (S) protein of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Our biosensing results from this simple, quick, and user-friendly method demonstrate high sensitivity and specificity and pave the way towards a point-of-care device for general use

Noise-induced chaos: A conditioned random dynamics perspective

<p>Data and Matlab code to reproduce "Noise-induced chaos: A conditioned random dynamics perspective"</p> <p><strong>Full Changelog</strong>: https://github.com/Bernat-BC/Ni-Chaos/commits/v1.0.0</p><p>If you use this code or the data for your research, please consider citing the original paper: https://arxiv.org/abs/2308.07116</p><p><br> </p&gt