biologia: Nonlinear system

Evidence: 89 • authority: 72

In mathematics and science, a nonlinear system (or a non-linear system) is a system in which the change of the output is not proportional to the change of the input. Nonlinear problems are of interest to engineers, biologists, physicists, mathematicians, and many other scientists since most systems are inherently nonlinear in nature. Nonlinear dynamical systems, describing changes in variables over time, may appear chaotic, unpredictable, or counterintuitive, contrasting with much simpler linear systems. Typically, the behavior of a nonlinear system is described in mathematics by a nonlinear system of equations, which is a set of simultaneous equations in which the unknowns (or the unknown…

Evidence: 66 • authority: 90

STATE ECONOMIC SECURITY AS A COMPLEX ADAPTIVE SYSTEM: THE COUNTERINTUITIVE LOGIC OF NEUTRALIZING ORGANIZED CRIME THREATS. This scientific article formulates the theoretical and methodological foundations for modeling economic security as a complex adaptive system capable of operating in an environment of criminal-economic uncertainty. The methodological basis of the study is an epistemological approach to the analysis of the outlined social phenomena. As a scientific novelty, based on the counterintuitive approach (J. W. Forrester) to explaining the behavior of socio-economic systems – where actions that appear logical often produce opposite results – the author proposes a concept of econom…

Evidence: 50 • authority: 92

A model of predation and survival in a system of three interacting species.. The study of intra-guild interactions in an ecosystem is an active and impactful direction of inquiry. This is true in particular for fragile systems in which even small perturbations of their functional parameters can produce dramatic effects like species endangerment or extinction, leading the system to enter an unsustainable regime and eventually collapse. In this context, it is important to understand which factors can lead to such effects and for which systems, so that one can act proactively and timely to prevent them. We built and studied a mathematical model that captures the natural interactions in an intr…

Evidence: 42 • authority: 92

Negative Differential Resistance Electronics: From Nonmonotonic Transport Physics to Functionally Compressed Computing.. Negative differential resistance (NDR), a counterintuitive transport phenomenon in which current decreases with increasing voltage, challenges conventional transistor-centric computing paradigms based on monotonic electronic transport and opens new opportunities for beyond-Boolean computing. Here, we present a comprehensive and concept-driven review of NDR devices spanning memristor-based, diode-type, and transistor-based platforms. We establish a unified framework that links diverse NDR mechanisms, including resonant tunneling, electrothermal feedback, defect dynamics, a…

Evidence: 42 • authority: 90

Ratchet behavior in nonlinear Klein-Gordon systems with pointlike inhomogeneities. We investigate the ratchet dynamics of nonlinear Klein-Gordon kinks in a periodic, asymmetric lattice of pointlike inhomogeneities. We explain the underlying rectification mechanism within a collective coordinate framework, which shows that such a system behaves as a rocking ratchet for point particles. Careful attention is given to the kink width dynamics and its role in the transport. We also analyze the robustness of our kink rocking ratchet in the presence of noise. We show that the noise activates unidirectional motion in a parameter range where such motion is not observed in the noiseless case. This is…

Evidence: 42 • authority: 90

Cross-scale interactions, nonlinearities, and forecasting catastrophic events. Catastrophic events share characteristic nonlinear behaviors that are often generated by cross-scale interactions and feedbacks among system elements. These events result in surprises that cannot easily be predicted based on information obtained at a single scale. Progress on catastrophic events has focused on one of the following two areas: nonlinear dynamics through time without an explicit consideration of spatial connectivity [Holling, C. S. (1992) Ecol. Monogr. 62, 447-502] or spatial connectivity and the spread of contagious processes without a consideration of cross-scale interactions and feedbacks [Zeng,…

Evidence: 42 • authority: 72

In population ecology, the paradox of enrichment is the idea that increasing the food available to a prey species can cause the predator's population to destabilize. The term was coined by Michael Rosenzweig in 1971, where he described an effect in six predator–prey models. A common example is that if the food supply of a prey such as a rabbit is overabundant, its population will grow unbounded and cause the predator population (such as a lynx) to grow unsustainably large. That may result in a crash in the population of the predators and possibly lead to local eradication or even species extinction. The term 'paradox' has been used since then to describe this effect in slightly conflicting…