Specific sleepiness symptoms are indicators of performance impairment during sleep deprivation

Drivers are not always aware that they are becoming impaired as a result of sleepiness. Using specific symptoms of sleepiness might assist with recognition of drowsiness related impairment and help drivers judge whether they are safe to drive a vehicle, however this has not been evaluated. In this study, 20 healthy volunteer professional drivers completed two randomized sessions in the laboratory – one under 24 h of acute sleep deprivation, and one with alcohol. The Psychomotor Vigilance Task (PVT) and a 30 min simulated driving task (AusEdTM) were performed every 3–4 h in the sleep deprivation session, and at a BAC of 0.00% and 0.05% in the alcohol session, while electroencephalography (EEG) and eye movements were recorded. After each test session, drivers completed the Karolinska Sleepiness Scale (KSS) and the Sleepiness Symptoms Questionnaire (SSQ), which includes eight specific sleepiness and driving performance symptoms. A second baseline session was completed on a separate day by the professional drivers and in an additional 20 non-professional drivers for test–retest reliability. There was moderate test–retest agreement on the SSQ (r = 0.59). Significant correlations were identified between individual sleepiness symptoms and the KSS score (r values 0.50–0.74, p < 0.01 for all symptoms). The frequency of all SSQ items increased during sleep deprivation (χ² values of 28.4–80.2, p < 0.01 for all symptoms) and symptoms were related to increased subjective sleepiness and performance deterioration. The symptoms “struggling to keep your eyes open”, “difficulty maintaining correct speed”, “reactions were slow” and “head dropping down” were most closely related to increased alpha and theta activity on EEG (r values 0.49–0.59, p < 0.001) and “nodding off to sleep” and “struggling to keep your eyes open” were related to slow eye movements (r values 0.67 and 0.64, p < 0.001). Symptoms related to visual disturbance and impaired driving performance were most accurate at detecting severely impaired driving performance (AUC on ROC curve of 0.86–0.91 for detecting change in lateral lane position greater than the change at a BAC of 0.05%). Individual sleepiness symptoms are related to impairment during acute sleep deprivation and might be able to assist drivers in recognizing their own sleepiness and ability to drive safely.     

The perceived utility of human and automated aids in a visual detection task

Although increases in the use of automation have occurred across society, research has found that human operators often underutilize (disuse) and overly rely on (misuse) automated aids (R. Parasuraman & V. Riley, 1997). Nearly 275 Cameron University students participated in 1 of 3 experiments performed to examine the effects of perceived utility (M. T. Dzindolet, H. P. Beck, L. G. Pierce, & L. A. Dawe, 2001) on automation use in a visual detection task and to compare reliance on automated aids with reliance on humans. Results revealed a bias for human operators to rely on themselves. Although self-report data indicate a bias toward automated aids over human aids, performance data revealed that participants were more likely to disuse automated aids than to disuse human aids. This discrepancy was accounted for by assuming human operators have a "perfect automation" schema. Actual or potential applications of this research include the design of future automateddecision aids and training procedures for operators relying on such aids.     

Play, creativity, and adaptive functioning: implications for play interventions

This study focuses on the potential role for nitric oxide on the actions of the parasympathetic innervation to the heart. Earlier, we showed that the nitric oxide synthase (NOS) inhibitor N omega-nitro-L-arginine methyl ester (L-NAME) reduced the bradycardia induced by stimulation of vagal efferent motor fibres and that these effects are reversible through administration of the NOS substrate L-arginine. In the present study, we show that D-arginine does not reverse the effects of the inhibitors and confirm that they are reversed by L-arginine. Another NOS inhibitor, NG-nitro-L-arginine (L-NOARG), produced similar effects which were not reversed by L-arginine. In an examination of the effect of increasing NO availability with the NO donor sodium nitroprusside the vagally induced bradycardia was enhanced at all frequencies tested. In a separate series, the effects of NOS inhibitors and NO donors on the dromotropic actions of the vagus were examined. The NOS inhibitor L-NAME, reduced the increase in atrio-ventricular conduction delay normally induced by efferent vagal stimulation at all frequencies tested both in the 'paced' and 'unpaced' heart. Further, sodium nitroprusside enhanced this delay. Overall the study indicates that NO has an important facilitatory role on both the chronotropic and dromotropic actions of the vagus nerve on the heart and that NO may be a rate-limiting factor in the cardiac responses to vagal stimulation.     

Development of strategies for reducing air pollutant emissions in the European community

In view of increasing economic and environmental problems, energy supply strategies as well as air pollutant emission reduction strategies are required. These strategies should be designed in accordance with the specific development of a country or region. In the past they were mainly considered with respect to the finiteness of natural resources and the scarcity of economic resources. In recent years the ‘joint-production’ of air pollutant emissions in the energy sector has been increasingly recognized as an additional argument. As a consequence, concepts on future energy pathways, which should be efficient with respect to both economic development and environmental protection, have to be devised. For this purpose energy-environmental models such as EFOM-ENV can be used as analytic tools. The paper discusses optimal future energy supply structures that result from different strategies for air-pollution control in the countries of the European Community. The results have been obtained by applying the energy flow optimization model (EFOM), which has been extended by additional environmental modules to EFOM-ENV. The issues of the paper are based on research activities that the authors are performing for the Commission of the European Communities (CEC), Brussels, and the European Research Center for Air Pollution Control Measures (PEF), Karlsruhe, in close co-operation with research institutes in member countries of the European Community.     

Simultaneous measurement of magnetic vortex polarity and chirality using scanning electron microscopy with polarization analysis (SEMPA)

The magnetic vortex structure is an equilibrium configuration frequently found in patterned magnetic nanostructures. It is characterized by an in-plane curling of the magnetization with clockwise or anticlockwise chirality and by an out-of-plane vortex core that can have a positive or negative polarity. The small size of the vortex core, on the order of 10 nm, makes it technologically interesting due to potential data storage, but also difficult to measure or image directly. In this work, we used Scanning Electron Microscopy with Polarization Analysis (SEMPA) to directly image magnetic vortex cores in patterned NiFe/Ta bilayer structures. With SEMPA we can simultaneously measure the in-plane and the out-of-plane component of the surface magnetization and thereby determine both the vortex chirality and the vortex core polarity in a single measurement. Our magnetic simulation of the vortex core, considering only the exchange and magnetostatic energy, is in good agreement with the SEMPA measurement of the magnetization when other experimental factors are taken into account.