Interlimb coupling strength scales with movement amplitude

The stability of rhythmic interlimb coordination is governed by the coupling between limb movements. While it is amply documented how coordinative performance depends on movement frequency, theoretical considerations and recent empirical findings suggest that interlimb coupling (and hence coordinative stability) is actually mediated more by movement amplitude. Here, we present the results of a reanalysis of the data of Post, Peper, and Beek (2000), which were collected in an experiment aimed at teasing apart the effects of frequency and amplitude on coordinative stability of both steady-state and perturbed in-phase and antiphase interlimb coordination. The dataset in question was selected because we found indications that the according results were prone to artifacts, which may have obscured the potential effects of amplitude on the post-perturbation stability of interlimb coordination. We therefore redid the same analysis based on movement signals that were normalized each half-cycle for variations in oscillation center and movement frequency. With this refined analysis we found that (1) stability of both steady-state and perturbed coordination indeed seemed to depend more on amplitude than on movement frequency per se, and that (2) whereas steady-state antiphase coordination became less stable with increasing frequency for prescribed amplitudes, in-phase coordination became more stable at higher frequencies. Such effects may have been obscured in previous studies due to (1) unnoticed changes in performed amplitudes, and/or (2) artifacts related to inappropriate data normalization. The results of the present reanalysis therefore give cause for reconsidering the relation between the frequency, amplitude, and stability of interlimb coordination.

Download Full-text

Subthalamic γ Activity Depends on Movement Amplitude and Velocity

Klinische Neurophysiologie ◽

10.1055/s-0031-1272681 ◽

2011 ◽

Vol 42 (01) ◽

Author(s):

A. Bock ◽

J. Huebl ◽

S. Siegert ◽

V. Litvak ◽

G.H. Schneider ◽

...

Keyword(s):

Movement Amplitude

Download Full-text

Determination of the quark coupling strength |Vub| using baryonic decays

Nature Physics ◽

10.1038/nphys3415 ◽

2015 ◽

Vol 11 (9) ◽

pp. 743-747 ◽

Cited By ~ 57

Author(s):

Keyword(s):

Coupling Strength ◽

Quark Coupling

Download Full-text

Dipole radiation and beyond from axion stars in electromagnetic fields

Journal of High Energy Physics ◽

10.1007/jhep06(2021)182 ◽

2021 ◽

Vol 2021 (6) ◽

Author(s):

Mustafa A. Amin ◽

Andrew J. Long ◽

Zong-Gang Mou ◽

Paul M. Saffin

Keyword(s):

Electromagnetic Fields ◽

Parametric Resonance ◽

Coupling Strength ◽

Coupling Parameter ◽

Strong Dependence ◽

Dipole Radiation ◽

Large Coupling ◽

External Electromagnetic Fields ◽

Order Of Magnitude ◽

Dimensionless Coupling

Abstract We investigate the production of photons from coherently oscillating, spatially localized clumps of axionic fields (oscillons and axion stars) in the presence of external electromagnetic fields. We delineate different qualitative behaviour of the photon luminosity in terms of an effective dimensionless coupling parameter constructed out of the axion-photon coupling, and field amplitude, oscillation frequency and radius of the axion star. For small values of this dimensionless coupling, we provide a general analytic formula for the dipole radiation field and the photon luminosity per solid angle, including a strong dependence on the radius of the configuration. For moderate to large coupling, we report on a non-monotonic behavior of the luminosity with the coupling strength in the presence of external magnetic fields. After an initial rise in luminosity with the coupling strength, we see a suppression (by an order of magnitude or more compared to the dipole radiation approximation) at moderately large coupling. At sufficiently large coupling, we find a transition to a regime of exponential growth of the luminosity due to parametric resonance. We carry out 3+1 dimensional lattice simulations of axion electrodynamics, at small and large coupling, including non-perturbative effects of parametric resonance as well as backreaction effects when necessary. We also discuss medium (plasma) effects that lead to resonant axion to photon conversion, relevance of the coherence of the soliton, and implications of our results in astrophysical and cosmological settings.

Download Full-text

Control of the coupling strength and linewidth of a cavity magnon-polariton

Physical Review Research ◽

10.1103/physrevresearch.2.013154 ◽

2020 ◽

Vol 2 (1) ◽

Cited By ~ 5

Author(s):

Isabella Boventer ◽

Christine Dörflinger ◽

Tim Wolz ◽

Rair Macêdo ◽

Romain Lebrun ◽

...

Keyword(s):

Coupling Strength

Download Full-text

Complex projection synchronization of fractional order uncertain complex-valued networks with time-varying coupling

Modern Physics Letters B ◽

10.1142/s0217984919503512 ◽

2019 ◽

Vol 33 (29) ◽

pp. 1950351 ◽

Cited By ~ 1

Author(s):

Dawei Ding ◽

Xiaolei Yao ◽

Hongwei Zhang

Keyword(s):

Fractional Order ◽

Coupling Strength ◽

Dynamic Networks ◽

Sufficient Conditions ◽

Feedback Gain ◽

Time Varying ◽

Order Complex ◽

Unknown Parameters ◽

Synchronization Problem ◽

Complex Valued

In this paper, the complex projection synchronization problem of fractional complex-valued dynamic networks is investigated. Considering the time-varying coupling and unknown parameters of the fractional order complex network, several decentralized adaptive strategies are designed to adjust the coupling strength and controller feedback gain in order to investigate the complex projection synchronization problem of the system. Moreover, based on the designed identification law, the uncertain parameters in the network can be estimated. Using adaptive law which balances the time-varying coupling strength and the feedback gain of the controller, some sufficient conditions are obtained for the complex projection synchronization of complex networks. Finally, numerical simulation examples are provided to illustrate the efficiency of the complex projection synchronization strategies of the fractional order complex dynamic networks.

Download Full-text

TRANSITION FREQUENCY OF STRONG-COUPLING IMPURITY BOUND POLARON IN AN ASYMMETRIC QUANTUM DOT

International Journal of Nanoscience ◽

10.1142/s0219581x12500263 ◽

2012 ◽

Vol 11 (03) ◽

pp. 1250026 ◽

Cited By ~ 4

Author(s):

CHENG-SHUN WANG ◽

YU-FANG CHEN ◽

JING-JIN XIAO

Keyword(s):

Excited State ◽

Coupling Strength ◽

State Energy ◽

Transition Frequency ◽

Phonon Coupling ◽

Excited State Energy ◽

Bound Polaron ◽

Asymmetric Quantum Dot ◽

Asymmetric Quantum ◽

Electron Phonon Coupling

Properties of the excited state of strong-coupling impurity bound polaron in an asymmetric quantum dot are studied by using linear combination operator and unitary transformation methods. The first internal excited state energy, the excitation energy and the transition frequency between the first internal excited and the ground states of the impurity bound polaron as functions of the transverse and the longitudinal effective confinement lengths of the dot, the electron–phonon coupling strength and the Coulomb bound potential were derived. Our numerical results show that they will increase with decreasing the effective confinement lengths, due to interesting quantum size confining effects. But they are an increasing functions of the Coulomb bound potential. The first internal excited state energy is a decreasing function of the electron–phonon coupling strength whereas the transition frequency and the excitation energy are an increasing one of the electron–phonon coupling strength.

Download Full-text

Magnetic-Field Dependence of Raman Coupling Strength in Ultracold 40 K Atomic Fermi Gas

Chinese Physics Letters ◽

10.1088/0256-307x/33/3/033401 ◽

2016 ◽

Vol 33 (3) ◽

pp. 033401

Author(s):

Liang-Hui Huang ◽

Peng-Jun Wang ◽

Zeng-Ming Meng ◽

Peng Peng ◽

Liang-Chao Chen ◽

...

Keyword(s):

Magnetic Field ◽

Field Dependence ◽

Coupling Strength ◽

Magnetic Field Dependence ◽

Fermi Gas ◽

Atomic Fermi Gas

Download Full-text

CELLULAR NEURAL NETWORKS CAN MIMIC SMALL-WORLD NETWORKS

International Journal of Bifurcation and Chaos ◽

10.1142/s0218127499001541 ◽

1999 ◽

Vol 09 (10) ◽

pp. 2105-2126 ◽

Cited By ~ 6

Author(s):

TAO YANG ◽

LEON O. CHUA

Keyword(s):

Neural Networks ◽

Coupling Strength ◽

Initial Conditions ◽

Computing Time ◽

Small World ◽

Cellular Neural Networks ◽

Clustering Coefficient ◽

High Survival ◽

Game Of Life ◽

Hole Detection

Small-world phenomenon can occur in coupled dynamical systems which are highly clustered at a local level and yet strongly coupled at the global level. We show that cellular neural networks (CNN's) can exhibit "small-world phenomenon". We generalize the "characteristic path length" from previous works on "small-world phenomenon" into a "characteristic coupling strength" for measuring the average coupling strength of the outputs of CNN's. We also provide a simplified algorithm for calculating the "characteristic coupling strength" with a reasonable amount of computing time. We define a "clustering coefficient" and show how it can be calculated by a horizontal "hole detection" CNN, followed by a vertical "hole detection" CNN. Evolutions of the game-of-life CNN with different initial conditions are used to illustrate the emergence of a "small-world phenomenon". Our results show that the well-known game-of-life CNN is not a small-world network. However, generalized CNN life games whose individuals have strong mobility and high survival rate can exhibit small-world phenomenon in a robust way. Our simulations confirm the conjecture that a population with a strong mobility is more likely to qualify as a small world. CNN games whose individuals have weak mobility can also exhibit a small-world phenomenon under a proper choice of initial conditions. However, the resulting small worlds depend strongly on the initial conditions, and are therefore not robust.

Download Full-text