Effect of environment fluctuations on pattern formation of single species

Silva, L. A. da; Colombo, Eduardo H.; Anteneodo, Celia

doi:10.1103/physreve.90.012813

Cited by 14 publications

(20 citation statements)

References 26 publications

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“…We note that the existence of a stable trapping potential for clusters of these dimensions is unexpected from single particle theories of acoustic radiation forces. Accordingly, theses observations call for a deeper understanding of the interaction of AVs with various particles involving multiple scattering processes and secondary forces and torques [42,43].…”

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confidence: 99%

Orbital Angular Momentum Transfer to Stably Trapped Elastic Particles in Acoustical Vortex Beams

2018

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The controlled rotation of solid particles trapped in a liquid by an ultrasonic vortex beam is observed. Single polystyrene beads, or clusters, can be trapped against gravity while simultaneously rotated. The induced rotation of a single particle is compared to a torque balance model accounting for the acoustic response of the particle. The measured torque (∼10 pN m for a driving acoustic power ∼40 W/cm^{2}) suggests two dominating dissipation mechanisms of the acoustic orbital angular momentum responsible for the observed rotation. The first takes place in the bulk of the absorbing particle, while the second arises as dissipation in the viscous boundary layer in the surrounding fluid. Importantly, the dissipation processes affect both the dipolar and quadrupolar particle vibration modes suggesting that the restriction to the well-known Rayleigh scattering regime is invalid to model the total torque even for spheres much smaller than the sound wavelength. The findings show that a precise knowledge of the probe elastic absorption properties is crucial to perform rheological measurements with maneuverable trapped spheres in viscous liquids. Further results suggest that the external rotational steady flow must be included in the balance and can play an important role in other liquids.

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confidence: 99%

Orbital Angular Momentum Transfer to Stably Trapped Elastic Particles in Acoustical Vortex Beams

2018

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“…These fragments, also known as patches, are not completely isolated as they are coupled due to movements of individuals in space. For modeling purposes, as a first step one can adopt a single patch viewpoint, taking into account the impact of the surrounding population in an effective manner [4][5][6][7]. As a further step beyond the single patch level, one can resort to a spatially explicit model.…”

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confidence: 99%

Metapopulation dynamics in a complex ecological landscape

Colombo

Anteneodo

2015

Phys. Rev. E

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We propose a general model to study the interplay between spatial dispersal and environment spatiotemporal fluctuations in metapopulation dynamics. An ecological landscape of favorable patches is generated like a Lévy dust, which allows to build a range of patterns, from dispersed to clustered ones. Locally, the dynamics is driven by a canonical model for the evolution of the population density, consisting of a logistic expression plus multiplicative noises. Spatial coupling is introduced by means of two spreading mechanisms: diffusive dispersion and selective migration driven by patch suitability. We focus on the long-time population size as a function of habitat configurations, environment fluctuations and coupling schemes. We obtain the conditions, that the spatial distribution of favorable patches and the coupling mechanisms must fulfill, to grant population survival. The fundamental phenomenon that we observe is the positive feedback between environment fluctuations and spatial spread preventing extinction.

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“…[9][10][11][12][13][14][15] Noise can be divided into two categories: extrinsic and intrinsic. The extrinsic noise can originate from the environment 16 and an external noise generator in experimental systems, whereas intrinsic noise is generated due to an interplay between the components of the systems and could be of small amplitude. But at sufficiently large values this intrinsic noise can also affect the deterministic dynamics of the system.…”

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confidence: 99%

Intrinsic noise induced coherence resonance in a glow discharge plasma

Shaw

Saha

Ghosh

et al. 2015

Chaos: An Interdisciplinary Journal of Nonlinear Science

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Experimental evidence of intrinsic noise induced coherence resonance in a glow discharge plasma is being reported. Initially the system is started at a discharge voltage (DV) where it exhibited fixed point dynamics, and then with the subsequent increase in the DV spikes were excited which were few in number and with further increase of DV the number of spikes as well as their regularity increased. The regularity in the interspike interval of the spikes is estimated using normalized variance. Coherence resonance was determined using normalized variance curve and also corroborated by Hurst exponent and power spectrum plots. We show that the regularity of the excitable spikes in the floating potential fluctuation increases with the increase in the DV, up to a particular value of DV. Using a Wiener filter, we separated the noise component which was observed to increase with DV and hence conjectured that noise can play an important role in the generation of the coherence resonance. From an anharmonic oscillator equation describing ion acoustic oscillations, we have been able to obtain a FitzHugh-Nagumo like model which has been used to understand the excitable dynamics of glow discharge plasma in the presence of noise. The numerical results agree quite well with the experimental results.

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Effect of environment fluctuations on pattern formation of single species

Cited by 14 publications

References 26 publications

Orbital Angular Momentum Transfer to Stably Trapped Elastic Particles in Acoustical Vortex Beams

Orbital Angular Momentum Transfer to Stably Trapped Elastic Particles in Acoustical Vortex Beams

Metapopulation dynamics in a complex ecological landscape

Intrinsic noise induced coherence resonance in a glow discharge plasma

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