Understanding the molecular mechanisms of transcriptional bursting

Microscopic origins of transcriptional bursting phenomena are discussed from the physical–chemical point of view.

Emergence of bursting in a network of memory dependent excitable and spiking leech-heart neurons

Excitable cells often produce different oscillatory activities that help us to understand the transmitting and processing of signals in the neural system. The diverse excitabilities of an individual neuron can be reproduced by a fractional-order biophysical model that preserves several previous memory effects. However, it is not completely clear to what extent the fractional-order dynamics changes the firing properties of excitable cells. In this article, we investigate the alternation of spiking and bursting phenomena of an uncoupled and coupled fractional leech-heart (L-H) neurons. We show that a complete graph of heterogeneous de-synchronized neurons in the backdrop of diverse memory settings (a mixture of integer and fractional exponents) can eventually lead to bursting with the formation of cluster synchronization over a certain threshold of coupling strength, however, the uncoupled L-H neurons cannot reveal bursting dynamics. Using the stability analysis in fractional domain, we demarcate the parameter space where the quiescent or steady-state emerges in uncoupled L-H neuron. Finally, a reduced-order model is introduced to capture the activities of the large network of fractional-order model neurons.

Three Dimensional Bursting Phenomena in Open Channel Bends

The turbulent coherent structure of flow in open channel bends is a stochastic process in nature. The coherence structure of the flow or bursting process is very important for the entrainment of sediment particles from the bed. In this study, first-order Markov process combined with three-dimensional quadrant analysis is applied to the measured turbulent data in open channel bends. The turbulent data was measured in an experimental flume using three-dimensional acoustic Doppler velocity meter (ADV). It was found that the stable movements of velocity fluctuations have higher transition probabilities than other movements, and the cross movements have the least transition probability. In addition, the internal group of events occurs more frequently than external group, particularly the internal ejection and internal sweep events and the probabilities decrease from the concave bank to the convex bank periodically, and reach the maximum at the top of the curved concave bank.