73 research outputs found
Estimation and quantification of vigilance using ERPs and eye blink rate with a fuzzy model-based approach
Physiological and autonomic stress responses after prolonged sleep restriction and subsequent recovery sleep in healthy young men
Purpose Sleep restriction is increasingly common and associated with the development of health problems. We investigated how the neuroendocrine stress systems respond to prolonged sleep restriction and subsequent recovery sleep in healthy young men. Methods After two baseline (BL) nights of 8 h time in bed (TIB), TIB was restricted to 4 h per night for five nights (sleep restriction, SR, n = 15), followed by three recovery nights (REC) of 8 h TIB, representing a busy workweek and a recovery weekend. The control group (n = 8) had 8 h TIB throughout the experiment. A variety of autonomic cardiovascular parameters, together with salivary neuropeptide Y (NPY) and cortisol levels, were assessed. Results In the control group, none of the parameters changed. In the experimental group, heart rate increased from 60 +/- 1.8 beats per minute (bpm) at BL, to 63 +/- 1.1 bpm after SR and further to 65 +/- 1.8 bpm after REC. In addition, whole day low-frequency to-high frequency (LF/HF) power ratio of heart rate variability increased from 4.6 +/- 0.4 at BL to 6.0 +/- 0.6 after SR. Other parameters, including salivary NPY and cortisol levels, remained unaffected. Conclusions Increased heart rate and LF/HF power ratio are early signs of an increased sympathetic activity after prolonged sleep restriction. To reliably interpret the clinical significance of these early signs of physiological stress, a follow-up study would be needed to evaluate if the stress responses escalate and lead to more unfavourable reactions, such as elevated blood pressure and a subsequent elevated risk for cardiovascular health problems.Peer reviewe
Electrochromic properties of WO3 as a single layer and in a full device: From the visible to the infrared
Poly(siloxane-g-styrene) and poly(siloxane-g-methylmethacrylate) by CuCl or Cu(0) catalyzed ATRP from benzyl chloride derivatized polysiloxanes
Radiocarbon Dates from the Oxford AMS System: Archaeometry
This is the thirty-sixth list of AMS radiocarbon determinations measured at the Oxford Radiocarbon Accelerator Unit (ORAU). Amongst some of the sites included here are the latest series of determinations from the key sites of El MirĂłn (Spain) and Sutton Courtney (UK), as well as others dating to the Palaeolithic, Mesolithic and later periods. Submitters of the material provide comments on the significance of the results
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