Search

The phase reduction approach has manifested its power in analyzing the rhythmic behaviors for limit cycle oscillators. For coherent oscillation purely induced by noise, e.g., the coherence resonance oscillator, the stochastic dynamics exhibit almost deterministic limit cycle phenomenon which inspires the application of the phase reduction approach to this kind of systems. In this paper, the FitzHugh–Nagumo system in coherence resonance is modeled as a jump process. The phase sensitivity is obtained by applying the phase reduction approach for the hybrid system. A modified direct method is proposed to compare the theoretical results with those of Monte Carlo simulation for the stochastic system, which shows a relatively good agreement for the perturbation not being too small. The phase reduction results of the coherent oscillators are applied to two coupled FitzHugh–Nagumo neurons. It is interesting that the phase difference of the coupled coherent oscillators does not converge as the deterministic oscillators, but forms a distribution where the peaks and valleys correspond to the stable and unstable synchronizations predicted by the phase coupling functions. The idea in this paper could be applied to other coherent oscillators where the stochastic dynamics follow almost deterministic paths.

Improvement of water quality has frequently been delayed due to high recycling rates of nutrients across the sediment–water interface in a reservoir. Diffusive fluxes and annual loads of ammonia nitrogen (NH4+-N) and phosphate (PO43−-P) in sediments from Guanting Reservoir (GTR) were estimated according to their vertical distribution. The average contents of NH4+-N and PO43−-P in surface pore water were higher by factors of 6.9 – 11.7 and 1.3 – 6.4 than those in overlying water, respectively. The ranges of fluxes were 1.59 – 13.0 (mg m2 d−1) for NH4+-N, and 0.002 – 0.196 (mg m2 d−1) for PO43−-P. The annual load contributions from sediments of GTR were 659 t a−1 for NH4+-N and 4.83 t a−1 for PO43−-P. Notably, the upstream of GTR accounted for 50.7% annual loads for NH4+-N, while the downstream contributed 71.2% loads to PO43−-P. This study will better inform future environmental management for the reservoir.

This research aimed to study the influence of principal–teacher management communication on teachers’ psychological empowerment, affective commitment, job performance, and the role that psychological empowerment and affective commitment plays in principal–teacher management communication and teacher performance. The participants were 868 teachers in primary and secondary schools in Beijing, Hubei, and other provinces in China. SEM was used to examine the mediating role of psychological empowerment and affective commitment. The study found that principal–teacher management communication can significantly predict teachers’ psychological empowerment, affective commitment. In addition, psychological empowerment and affective commitment partially mediate managerial communication and teacher performance.

This study investigates the mediating role of teachers’ psychological empowerment and the moderating role of team psychological safety in the relationship between empowering leadership and teachers’ innovative behavior in teaching and research groups (TR groups) as professional learning communities. In total, 507 teachers from 114 TR groups in China participated in this study. The multilevel model results show that empowering leadership improves teachers’ innovative behavior by increasing teachers’ psychological empowerment, which is not influenced by team psychological safety. A supplementary analysis shows that the relationship between team psychological safety and teachers’ innovative behavior is also mediated by psychological empowerment.

In the present paper, a simple spike timing distance is defined which can be used to measure the degree of synchronization with the information only encoded in the precise timing of the spike trains. Via calculating the spike timing distance defined in this paper, the spike train similarity of uncoupled Hindmarsh–Rose neurons in bursting or spiking states with different initial conditions is investigated and the results are compared with other spike train distance measures. Later, the spike timing distance measure is applied to study the synchronization of coupled or common noise-stimulated neurons. Counterintuitively, the addition of weak coupling or common noise doesn’t enhance the degree of synchronization although after critical values, both of them can induce complete synchronizations. More interestingly, the common noise plays opposite roles for weak and strong enough couplings. Finally, it should be noted that the measure defined in this paper can be extended to measure large neuronal ensembles and the lag synchronization.