The sleep spindle is an event in the electroencephalogram (EEG) characterizing Stage 2 sleep. Sleep spindles may reflect, at the electrophysiological level, an ideal mechanism for inducing long-term synaptic changes in the neocortex. Recent evidence suggests the spindle is highly correlated with tests of intellectual ability (e.g.; IQtests) selleck inhibitor and may serve as a physiological index of intelligence. Further, spindles

increase in number and duration in sleep following new learning and are correlated with performance improvements. Spindle density and sigma (14-16 Hz) spectral power have been found to be positively correlated with performance following a daytime nap, and animal studies suggest the spindle is involved in a hippocampal-neocortical dialogue necessary for memory consolidation. The findings reviewed here collectively provide a compelling body of evidence that the function of the sleep spindle is related to intellectual ability and memory consolidation. (C) 2010 Elsevier Ltd. All rights reserved.”
“It has long been known to control theorists and engineers that integral feedback control leads to, and is necessary for, “”perfect”" adaptation to step input perturbations in most systems. Consequently, implementation of this robust control strategy in a synthetic gene network is an attractive prospect. However, the nature

of genetic regulatory networks (density-dependent kinetics and molecular signals that easily reach saturation) implies that the design and construction of such a device is not straightforward. In this study, WH-4-023 we propose a generic two-promoter genetic regulatory network for the purpose of exhibiting perfect adaptation; our treatment highlights the challenges inherent in the implementation of a genetic integral controller. We also present a numerical case study for a specific realization of this two-promoter network, “”constructed”" using commonly available parts from U0126 clinical trial the bacterium Escherichia coil. We illustrate the possibility of optimizing this network’s transient response via analogy to a linear, free-damped

harmonic oscillator. Finally, we discuss extensions of this two-promoter network to a proportional-integral controller and to a three-promoter network capable of perfect adaptation under conditions where first-order protein removal effects would otherwise disrupt the adaptation. (c) 2010 Elsevier Ltd. All rights reserved.”
“Models of reproductive skew assume reproductive shares are either conceded, competed over, or both. Previous mathematical evaluations found that simultaneous concessions and contests are evolutionarily unstable. Recently, Shen and Reeve (2010) challenged these conclusions and developed a series of sub-models they argued to be a unified approach to reproductive skew: the general bordered tug-of-war (BTOW).