2,876 research outputs found

    Mental Workload of Voice Interactions with 6 Real-World Driver Interfaces

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    Hands-free voice interaction is an increasingly common option in new vehicles. Recent research suggests that hands-free interactions with speech-to-text systems may require significantly more cognitive effort than previously anticipated. This high level of mental workload may both keep drivers from using the technology and potentially create additional safety concerns for the driver. However, little prior research has measured the cognitive demands of simple voice based tasks using real-world systems. The current study evaluated the mental demands of a small set of auditory-vocal vehicle commands using five 2013 and one 2012 model year OEM infotainment systems. Results indicate that well executed voice systems impose little additional cognitive demand while poorly executed systems may significantly elevate workload

    Cognitive Distraction Impairs Drivers\u27 Anticipatory Glances: An On-Road Study

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    This study assessed the impact of cognitive distraction on drivers’ anticipatory glances. Participants drove an instrumented vehicle and executed a number of secondary tasks associated with increasing levels of mental workload including: listening to the radio or audiobook, talking on a handheld or hands-free cellphone, interacting with a voice-based e-mail/text system, and executing a highly demanding task (Operational Span task; OSPAN). Drivers’ visual scanning behavior was recorded by four different high definition cameras and coded offline frame-by-frame. Visual scanning behavior at road intersections with crosswalks was targeted because distraction is one of the major causes of accidents at these locations (NHTSA, 2010a). Despite the familiarity of the locations, results showed that as the secondary-task became more cognitively demanding drivers reduced the amount of anticipatory glances to potential hazards locations. For example, while interacting with a high fidelity voice-based email/text system, the probability of executing a complete scan of the intersection was reduced by 11% compared to the no-distraction control condition. These results document the effects of cognitive distraction on drivers’ visual scanning for potential hazards and highlight the detrimental role of voice based systems on driving behavior

    Assessing Cognitive Distraction Using Event Related Potentials

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    This report examines the utility of using Event-Related Brain Potentials (ERPs) to evaluate cognitive distraction in the context of driving an automobile. Across two studies, ERPs (both P300 latency and P300 amplitude) were found to be effective in quantifying the cognitive workload experienced by drivers when they interact with in-vehicle voice-command systems

    AEGIS: New Evidence Linking Active Galactic Nuclei to the Quenching of Star Formation

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    Utilizing Chandra X-ray observations in the All-wavelength Extended Groth Strip International Survey (AEGIS) we identify 241 X-ray selected Active Galactic Nuclei (AGNs, L > 10^{42} ergs/s) and study the properties of their host galaxies in the range 0.4 < z < 1.4. By making use of infrared photometry from Palomar Observatory and BRI imaging from the Canada-France-Hawaii Telescope, we estimate AGN host galaxy stellar masses and show that both stellar mass and photometric redshift estimates (where necessary) are robust to the possible contamination from AGNs in our X-ray selected sample. Accounting for the photometric and X-ray sensitivity limits of the survey, we construct the stellar mass function of X-ray selected AGN host galaxies and find that their abundance decreases by a factor of ~2 since z~1, but remains roughly flat as a function of stellar mass. We compare the abundance of AGN hosts to the rate of star formation quenching observed in the total galaxy population. If the timescale for X-ray detectable AGN activity is roughly 0.5-1 Gyr--as suggested by black hole demographics and recent simulations--then we deduce that the inferred AGN "trigger" rate matches the star formation quenching rate, suggesting a link between these phenomena. However, given the large range of nuclear accretion rates we infer for the most massive and red hosts, X-ray selected AGNs may not be directly responsible for quenching star formation.Comment: 12 pages. Submitted to ApJ. Comments welcom

    Using Published HRTFS with Slab3D: Metric-Based Database Selection and Phenomena Observed

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    Presented at the 20th International Conference on Auditory Display (ICAD2014), June 22-25, 2014, New York, NY.In this paper, two publicly available head-related transfer function (HRTF) database collections are analyzed for use with the open-source slab3d rendering system. After conversion to the slab3d HRTF database format (SLH), a set of visualization tools and a five-step metric-based process are used to select a subset of databases for general use. The goal is to select a limited subset least likely to contain anomalous behavior or measurement error. The described set of open-source tools can be applied to any HRTF database converted to the slab3d format

    Pretreatment with phenoxybenzamine attenuates the radial artery's vasoconstrictor response to α-adrenergic stimuli

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    AbstractBackgroundAlthough the radial artery bypass conduit has excellent intermediate-term patency, it has a proclivity to vasospasm. We tested the hypothesis that brief pretreatment of a radial artery graft with the irreversible adrenergic antagonist phenoxybenzamine attenuates the vasoconstrictor response to the vasopressors phenylephrine and norepinephrine compared with the currently used papaverine/lidocaine.MethodsSegments of human radial artery grafts were obtained after a 30-minute intraoperative pretreatment with a solution containing 20 mL of heparinized blood, 0.4 mL of papaverine (30 mg/mL), and 1.6 mL of lidocaine (1%). The segments were transported to the laboratory and placed into a bath containing Krebs-Henseleit solution and 10, 100, or 1000 ÎŒmol/L phenoxybenzamine or vehicle. The segments were tested in organ chambers for contractile responses to increasing concentrations of phenylephrine and norepinephrine (0.5-15 ÎŒmol/L).ResultsContractile responses to 15 ÎŒmol/L phenylephrine in control radial artery segments averaged 44.2% ± 9.1% of the maximal contractile response to 30 mmol/L KCl. Papaverine/lidocaine modestly attenuated contraction to 15 ÎŒmol/L phenylephrine (32.1% ± 5.9%; P = .22), but 1000 ÎŒmol/L phenoxybenzamine completely abolished radial artery contraction (−7.2% ± 4.4%; P < .001). The effect of 10 and 100 ÎŒmol/L phenoxybenzamine on attenuating vasocontraction was intermediate between 1000 ÎŒmol/L phenoxybenzamine and papaverine/lidocaine. Responses to 15 ÎŒmol/L norepinephrine in control radial artery segments averaged 54.7% ± 7.5% of maximal contraction to 30 mmol/L KCl. Papaverine/lidocaine modestly attenuated the contraction response of radial artery segments (35.6% ± 5.1%; P = .04). In contrast, 1000 ÎŒmol/L phenoxybenzamine showed the greatest attenuation of norepinephrine-induced contraction (−10.5% ± 2.0%; P < .001).ConclusionsA brief pretreatment of the human radial artery bypass conduit with 1000 ÎŒmol/L phenoxybenzamine completely attenuates the vasoconstrictor responses to the widely used vasopressors norepinephrine and phenylephrine. Papaverine/lidocaine alone did not block vasoconstriction to these α-adrenergic agonists

    Stellar Mass--Gas-phase Metallicity Relation at 0.5≀z≀0.70.5\leq z\leq0.7: A Power Law with Increasing Scatter toward the Low-mass Regime

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    We present the stellar mass (M∗M_{*})--gas-phase metallicity relation (MZR) and its scatter at intermediate redshifts (0.5≀z≀0.70.5\leq z\leq0.7) for 1381 field galaxies collected from deep spectroscopic surveys. The star formation rate (SFR) and color at a given M∗M_{*} of this magnitude-limited (Râ‰Č24R\lesssim24 AB) sample are representative of normal star-forming galaxies. For masses below 109M⊙10^9 M_\odot, our sample of 237 galaxies is ∌\sim10 times larger than those in previous studies beyond the local universe. This huge gain in sample size enables superior constraints on the MZR and its scatter in the low-mass regime. We find a power-law MZR at 108M⊙<M∗<1011M⊙10^{8} M_\odot < M_{*} < 10^{11} M_\odot: 12+log(O/H)=(5.83±0.19)+(0.30±0.02)log(M∗/M⊙){12+log(O/H) = (5.83\pm0.19) + (0.30\pm0.02)log(M_{*}/M_\odot)}. Our MZR shows good agreement with others measured at similar redshifts in the literature in the intermediate and massive regimes, but is shallower than the extrapolation of the MZRs of others to masses below 109M⊙10^{9} M_\odot. The SFR dependence of the MZR in our sample is weaker than that found for local galaxies (known as the Fundamental Metallicity Relation). Compared to a variety of theoretical models, the slope of our MZR for low-mass galaxies agrees well with predictions incorporating supernova energy-driven winds. Being robust against currently uncertain metallicity calibrations, the scatter of the MZR serves as a powerful diagnostic of the stochastic history of gas accretion, gas recycling, and star formation of low-mass galaxies. Our major result is that the scatter of our MZR increases as M∗M_{*} decreases. Our result implies that either the scatter of the baryonic accretion rate or the scatter of the M∗M_{*}--MhaloM_{halo} relation increases as M∗M_{*} decreases. Moreover, our measures of scatter at z=0.7z=0.7 appears consistent with that found for local galaxies.Comment: 18 pages, 10 figures. Accepted by ApJ. Typos correcte
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