106 research outputs found

    Electrophysiological Brain-Cardiac Coupling in Train Drivers during Monotonous Driving

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    Electrophysiological research has previously investigated monotony and the cardiac health of drivers independently; however, few studies have explored the association between the two. As such the present study aimed to examine the impact of monotonous train driving (indicated by electroencephalogram (EEG) activity) on an individual's cardiac health as measured by heart rate variability (HRV). Sixty-three train drivers participated in the present study, and were required to complete a monotonous train driver simulator task. During this task, a 32 lead EEG and a three-lead electrocardiogram were recorded from each participant. In the present analysis, the low (LF) and high frequency (HF) HRV parameters were associated with delta (p < 0.05), beta (p = 0.03) and gamma (p < 0.001) frequency EEG variables. Further, total HRV was associated with gamma activity, while sympathovagal balance (i.e., LF:HF ratio) was best associated fronto-temporal delta activity (p = 0.02). HRV and EEG parameters appear to be coupled, with the parameters of the delta and gamma EEG frequency bands potentially being the most important to this coupling. These relationships provide insight into the impact of a monotonous task on the cardiac health of train drivers, and may also be indicative of strategies employed to combat fatigue or engage with the driving task

    Electric-Field-Induced Mott Insulating States in Organic Field-Effect Transistors

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    We consider the possibility that the electrons injected into organic field-effect transistors are strongly correlated. A single layer of acenes can be modelled by a Hubbard Hamiltonian similar to that used for the kappa-(BEDT-TTF)(2)X family of organic superconductors. The injected electrons do not necessarily undergo a transition to a Mott insulator state as they would in bulk crystals when the system is half-filled. We calculate the fillings needed for obtaining insulating states in the framework of the slave-boson theory and in the limit of large Hubbard repulsion, U. We also suggest that these Mott states are unstable above some critical interlayer coupling or long-range Coulomb interaction.Comment: 9 pages, 7 figure

    Ranavirus Host Immunity and Immune Evasion

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    Spectroscopy and Dynamics of Jet-Cooled Styrene-Ammonia Clusters

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    Author Institution: The Hebrew University of Jerusalem, Jerusalem, IsraelThe S0↔S1S_{0} \leftrightarrow S_{1} absorption and emission spectra of styrene have been analyzed with the help of an ab-initio calculation. It was found that out-of-plane vibrations undergo, in general, a red shift upon electronic excitation, while in-plane ones are not appreciably changed. An important exception to this rule is the ν17\nu_{17} mode, which is similar the ν14(b2u)\nu_{14}(b_{2u}) mode of benzene - it shows a considerable frequency increase upon excitation. The analysis led to some new assignments of certain vibronic transitions. In addition, the spectra of styrene-ammonia adducts were recorded. Cluster formation affects the frequencies of some normal modes of S1S_{1} to a small but easily measured extent. It was found that in general, out-of-plane modes were blue shifted with respect to the bare molecule, while in-plane modes were essentially unchanged. Vibronic bands leading to out-of-plane in the cluster appear to be less intense than in the bare molecule; in contrast, some bands at about 500cm−1500 cm^{-1} are found to have a considerably more intense than the corresponding bare molecule ones. These bands are due to a mode similar to the ν6(e1m)\nu_{6}(e_{1m}) mode of benzene, responsible for the vibronic coupling that makes the 1Ag↔1B2u^{1}A_{g} \leftrightarrow ^{1}B_{2u} transition weakly allowed. The dissociation energy of the styrene-ammonia cluster was roughly determined, by recording the dispersed emission spectra following excitation of the cluster to different vibronic levels. It was found to be 650±100650 \pm 100 for S1S_{1} and 600±100600\pm 100 for S0S_{0}

    Methodology and initial analysis results for development of non-invasive and hybrid driver drowsiness detection systems

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    Application of piezofilm movement sensors integrated into the car seat, seat belt and steering wheel was proposed for development of a non-invasive and hybrid systems for detecting driver drowsiness. A car simulator study was designed to collect physiological data for validation of this technology. Methodology for analysis of physiological data, independent assessment of driver drowsiness and development of drowsiness detection algorithm by means of sequential fitting and selection of regression models is presented. Statistical analysis shows that during the episodes of transitions to dangerous levels of drowsiness movement variations recorded by the seat sensors are decreasing. This finding indicates that the piezofilm movement sensors could be used as noninvasive devices for detecting the level of drowsiness on their own or in combination with other physiological signals. © 2007 IEEE
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