Ageing is associated with changes in sleep and decline executive functions, such as task-switching and task preparation. Given that sleep affects executive function, age-related changes in executive function may be attributable to changes in sleep. The present study used a sleep detection device to examine whether or not wake time after sleep onset and total sleep time moderated age differences...

BACKGROUND Despite the common experience that interrupted sleep has a negative impact on waking function, the features of human sleep-wake architecture that best distinguish sleep continuity versus fragmentation remain elusive. In this regard, there is growing interest in characterizing sleep architecture using models of the temporal dynamics of sleep-wake stage transitions. In humans and other...

The formation of lee wakes and vortices is explored in the context of stratified flow with uniform basic-state wind and stability past elongated free-slip ridges. The theory of inviscid flow past a ridge of small nondimensional height e is revisited using a weakly nonlinear semianalytic model to compute flow fields through O(e2). Consistent with previous work, the weakly nonlinear solutions sho...

This paper discusses the definition of the state space and corresponding choice sets that figure in the theory of decision making under uncertainty. It elucidates an approach that overcomes some conceptual difficulties with the standard models and accommodates a procedure for expanding the state space in the wake of growing awareness.

in this paper, considering the importance of incoming flow turbulence intensity into combustion chamber, tripping wire effect on the flow wake has been experimentally investigated within a linear compressor cascade. to do this, two wires were implemented along each blade and their effects on average velocity, turbulence intensity and vortices frequencies at reynolds number 45500 were accurately...

the shape of wake behind a wind turbine is normally assumed to have a hat shape for the models used in wind farm layout optimization purposes; however, it is know from experimental tests and numerical simulations that this is not a real assumption. in reality, the results of actual measurements and detailed numerical simulation show that the velocity in wake region has a s-shape profile. the pr...

My favourite Simon Armitage poem, ‘Homecoming’, begins, ‘Think, two things on their own and both at once’, tells, in brief, through juxtapositions of imagery, the story a subject, ‘you’, l...

Mathematical modeling has played a significant role in building our understanding of sleep-wake and circadian behavior. Over the past 40 years, phenomenological models, including the two-process model and oscillator models, helped frame experimental results and guide progress in understanding the interaction of homeostatic and circadian influences on sleep and understanding the generation of ra...

Recent evidence suggests that dopamine plays an important role in arousal, but the location of the dopaminergic neurons that may regulate arousal remains unclear. It is sometimes assumed that the dopaminergic neurons in the ventral tegmental area that project to the prefrontal cortex and striatum may regulate the state of arousal; however, the firing of these dopaminergic neurons does not corre...

To better understand the neurobiology of sleep disorders, detailed understanding of circadian and homeostatic sleep-wake regulation in healthy volunteers is mandatory. Sleep physiology and the repercussions of experimentally-induced sleep deprivation on sleep and waking electroencephalogram (EEG), vigilance and subjective state are highly variable, even in healthy individuals. Accumulating evid...