A ring generator of two- and three-frequency quasiperiodic self-oscillations based on the van der Pol oscillator.

In this work, we present a model of an autonomous three-mode ring generator based on the van der Pol oscillator, where periodic, two-frequency quasiperiodic, three-frequency quasiperiodic, and chaotic self-oscillations are observed. The transitions to chaos occur as a result of a sequence of torus doubling bifurcations. When the control parameters are varied, the resonant limit cycles appear on a two-dimensional torus, and two-dimensional tori appear on a three-dimensional torus as a result of synchronization.

The emergence of multistability and chaos in a two-mode van der Pol generator versus different connection types of linear oscillators.

In this work, we study the multistability and chaos phenomena in a classical two-mode van der Pol generator which consists of a nonlinear element and two linear oscillators. We show that the configuration of the connections of the linear oscillators in the two-mode self-oscillating system significantly affects its oscillation regimes and bifurcational transitions. In the case of the feedback loop including one oscillator, the two-mode system demonstrates the well-known effect of frequency entrainment, including bistability and hysteresis phenomena.

Deceleration of probe beam by stage bias potential improves resolution of serial block-face scanning electron microscopic images.

Serial block-face scanning electron microscopy (SBEM) is quickly becoming an important imaging tool to explore three-dimensional biological structure across spatial scales. At probe-beam-electron energies of 2.0 keV or lower, the axial resolution should improve, because there is less primary electron penetration into the block face.

Early experiences in developing and managing the neuroscience gateway.

The last few decades have seen the emergence of computational neuroscience as a mature field where researchers are interested in modeling complex and large neuronal systems and require access to high performance computing machines and associated cyber infrastructure to manage computational workflow and data. The neuronal simulation tools, used in this research field, are also implemented for parallel computers and suitable for high performance computing machines. But using these tools on complex high performance computing machines remains a challenge because of issues with acquiring computer time on these machines located at national supercomputer centers, dealing with complex user interface of these machines, dealing with data management and retrieval.

A survey of the neuroscience resource landscape: perspectives from the neuroscience information framework.

The number of available neuroscience resources (databases, tools, materials, and networks) available via the Web continues to expand, particularly in light of newly implemented data sharing policies required by funding agencies and journals. However, the nature of dense, multifaceted neuroscience data and the design of classic search engine systems make efficient, reliable, and relevant discovery of such resources a significant challenge. This challenge is especially pertinent for online databases, whose dynamic content is largely opaque to contemporary search engines.