2,658 research outputs found

    Characterizing the Effect of Videophone Conversations on Intersection Driving Performance

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    The present study examined the efficacy of videophone conversations for enhancing conversation partner situational awareness and mitigating cell phone distraction during intersection drives. Younger and older drivers drove through simulated intersections in four conditions: undistracted, with an in-car passenger, with a remote partner who could see the driver and a subset of the driving scene via a videophone, and with a remote partner on a cell phone. Relative to the cell phone condition, passenger and videophone conversations enhanced situational awareness and mitigated distraction. Younger and older drivers showed similar benefits, although there were age-related costs to driving performance overall. Videophone information offers a simple and promising potential strategy to enhance partner situational awareness during cell phone conversations, even when the conversation partner can see only a subset of the driving scene

    Some exact non-vacuum Bianchi VI0 and VII0 instantons

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    We report some new exact instantons in general relativity. These solutions are K\"ahler and fall into the symmetry classes of Bianchi types VI0 and VII0, with matter content of a stiff fluid. The qualitative behaviour of the solutions is presented, and we compare it to the known results of the corresponding self-dual Bianchi solutions. We also give axisymmetric Bianchi VII0 solutions with an electromagnetic field.Comment: latex, 15 pages with 3 eps figure

    The Transit Light Curve Project. VII. The Not-So-Bloated Exoplanet HAT-P-1b

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    We present photometry of the G0 star HAT-P-1 during six transits of its close-in giant planet, and we refine the estimates of the system parameters. Relative to Jupiter's properties, HAT-P-1b is 1.20 +/- 0.05 times larger and its surface gravity is 2.7 +/- 0.2 times weaker. Although it remains the case that HAT-P-1b is among the least dense of the known sample of transiting exoplanets, its properties are in accord with previously published models of strongly irradiated, coreless, solar-composition giant planets. The times of the transits have a typical accuracy of 1 min and do not depart significantly from a constant period.Comment: To appear in AJ [19pg, 3 figures]. New co-author added. Minor revisions to match published versio

    Falls Risk and Simulated Driving Performance in Older Adults

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    Declines in executive function and dual-task performance have been related to falls in older adults, and recent research suggests that older adults at risk for falls also show impairments on real-world tasks, such as crossing a street. The present study examined whether falls risk was associated with driving performance in a high-fidelity simulator. Participants were classified as high or low falls risk using the Physiological Profile Assessment and completed a number of challenging simulated driving assessments in which they responded quickly to unexpected events. High falls risk drivers had slower response times (~2.1 seconds) to unexpected events compared to low falls risk drivers (~1.7 seconds). Furthermore, when asked to perform a concurrent cognitive task while driving, high falls risk drivers showed greater costs to secondary task performance than did low falls risk drivers, and low falls risk older adults also outperformed high falls risk older adults on a computer-based measure of dual-task performance. Our results suggest that attentional differences between high and low falls risk older adults extend to simulated driving performance

    Bianchi VIII Empty Futures

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    Using a qualitative analysis based on the Hamiltonian formalism and the orthonormal frame representation we investigate whether the chaotic behaviour which occurs close to the initial singularity is still present in the far future of Bianchi VIII models. We describe some features of the vacuum Bianchi VIII models at late times which might be relevant for studying the nature of the future asymptote of the general vacuum inhomogeneous solution to the Einstein field equations.Comment: 22 pages, no figures, Latex fil

    Spin-Orbit Alignment for the Eccentric Exoplanet HD 147506b

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    The short-period exoplanet HD 147506b (also known as HAT-P-2b) has an eccentric orbit, raising the possibility that it migrated through planet-planet scattering or Kozai oscillations accompanied by tidal dissipation. Either of these scenarios could have significantly tilted the orbit relative to the host star's equatorial plane. Here we present spectroscopy of a transit of HD 147506b and assess the spin-orbit alignment via the Rossiter-McLaughlin effect. We find the angle between the sky projections of the stellar spin axis and orbital axis to be aligned within 14°. Thus, we find no corroborating evidence for scattering or Kozai migration, although these scenarios cannot be ruled out with the present data

    The 10th Biennial Hatter Cardiovascular Institute workshop: cellular protection—evaluating new directions in the setting of myocardial infarction, ischaemic stroke, and cardio-oncology

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    Due to its poor capacity for regeneration, the heart is particularly sensitive to the loss of contractile cardiomyocytes. The onslaught of damage caused by ischaemia and reperfusion, occurring during an acute myocardial infarction and the subsequent reperfusion therapy, can wipe out upwards of a billion cardiomyocytes. A similar program of cell death can cause the irreversible loss of neurons in ischaemic stroke. Similar pathways of lethal cell injury can contribute to other pathologies such as left ventricular dysfunction and heart failure caused by cancer therapy. Consequently, strategies designed to protect the heart from lethal cell injury have the potential to be applicable across all three pathologies. The investigators meeting at the 10th Hatter Cardiovascular Institute workshop examined the parallels between ST-segment elevation myocardial infarction (STEMI), ischaemic stroke, and other pathologies that cause the loss of cardiomyocytes including cancer therapeutic cardiotoxicity. They examined the prospects for protection by remote ischaemic conditioning (RIC) in each scenario, and evaluated impasses and novel opportunities for cellular protection, with the future landscape for RIC in the clinical setting to be determined by the outcome of the large ERIC-PPCI/CONDI2 study. It was agreed that the way forward must include measures to improve experimental methodologies, such that they better reflect the clinical scenario and to judiciously select combinations of therapies targeting specific pathways of cellular death and injury

    In-vehicle Drowsy Driving Detection and Alerting

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    DTNH2211D00237/0014Drowsy driving is a common phenomenon that increases the risk for fatal and injurious crashes. Technological innovations in the form of driver monitoring and notification systems may offer potential to reduce crashes due to drowsy driving. These systems monitor the driver\u2019s drowsy driving state and issue alerts when the driver is classified by the system as drowsy. Research shows that driver notification can be effective in improving performance over relatively short drives. However, the efficacy of such systems for improving performance and changing drowsy driver decision making over longer drives is unknown. The goal of this project was to evaluate the efficacy of two notifications, a lane departure warning (LDW) and a drowsiness notification with LDW (DN/LDW). The notification conditions were compared against a no-notification baseline during 4-hour overnight drives in a high-fidelity driving simulator with an incentive method designed to replicate the motivational tradeoffs common to drowsy driving, i.e., the desire to reach a destination versus one\u2019s own safety while driving drowsy. The combined DN/LDW, but not the LDW, was effective in reducing the frequency of lane departures and also in reducing the percentage of eyelid closure (PERCLOS) prior to lane departure events compared to baseline. There was no difference between the notification conditions and baseline with respect to the frequency or timing of breaks to rest, suggesting that although notifications improved driving performance, they did not alter decision making. These results suggest that notifications may aid drowsy drivers, but in-vehicle alerts may not be effective in changing the way drowsy drivers make decisions about whether and when to stop to rest
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