We analyse the stability of the spring inverted pendulum with the vertical oscillations of the suspension point. An important factor in the stability analysis is the interaction between radial and oscillating modes. In addition to the small oscillations near the upper position, the nonlinearity of the problem leads to the appearance of limit-cycle oscillations of finite amplitudes.

In the Drosophila circadian clock, the CLOCK/CYCLE complex activates the period and timeless genes that negatively feedback on CLOCK/CYCLE activity. The 24-h pace of this cycle depends on the stability of the clock proteins. RING-domain E3 ubiquitin ligases have been shown to destabilize PERIOD or TIMELESS. Here we identify a clock function for the circadian trip (ctrip) gene, which encodes a H...

We derived analytically and checked numerically a set of novel conditions for the existence and the stability of phase-locked modes in a biologically relevant master-slave neural network with a dynamic feedback loop. Since neural oscillators even in the three-neuron network investigated here receive multiple inputs per cycle, we generalized the concept of phase resetting to accommodate multiple...

We investigate the behaviour of a neural network model consisting of three neurons with delayed self and nearest-neighbour connections. We give analytical results on the existence, stability and bifurcation of nontrivial equilibria of the system. We show the existence of codimension two bifurcation points involving both standard and D3-equivariant, Hopf and pitchfork bifurcation points. We use ...

How extracellular signals communicate with the cell cycle is poorly understood. In this issue, two papers address this problem by reporting phosphorylation of the cyclin-dependent kinase inhibitor p27Kip1 on a tyrosine residue by nonreceptor tyrosine kinases, which decreases p27 stability. This new mechanism could explain how cells enter the cell cycle from a quiescent state.

The Lotka – Volterra equation for three species are integrated in an original way obtaining the existence of cycle. No studies of the cycle stability are held. These would be very interesting kind as in two species. However our results are of value.

Global assays of gene expression and protein stability during the Caulobacter crescentus cell cycle reveal that a surprisingly large fraction of the genome and proteome is affected as cells grow and divide. These studies are an important step toward understanding how the cell cycle is controlled in prokaryotes.

In this paper, we propose and study an adaptive delta modulator that has improved SNR performance and better robustness in tracking highly varying signals. The step-size adaptation used in this modulator is based on information about the absolute value of the quantizer input. The modulator is shown to be free of zero-input limit cycles and is BIBO stable.

It is well known that passive walking robot can dynamically walk down with a steady gait by only powered gravity. The dynamics of passive walking has interesting characteristics of stability and bifurcation. Since passive gait is natural motion, investigation of passive walking may lead us to understand human locomotion and design for active walking robot. In this paper, the dynamics of passive...

introduction: soil structural stability affects the profitability and sustainability of agricultural systems. particle size distribution (psd) and aggregate stability are the important characteristics of soil. aggregate stability has a significant impact on the development of the root system, water and carbon cycle and soil resistance against soil erosion. soil aggregate stability, defined as t...