Effect of altered vision on constant load exercise performance while wearing a respirator

Previous testing has shown that visual acuity greatly influences task performance at light work rate levels. At moderate to heavy work rates, however, the Performance Rating Table (PRT) predicts almost no visual acuity effect. This experiment was performed to determine if the PRT value is realistic. Ten subjects walked on a treadmill at 75-80% of their maximum heart rates until their voluntary end points. Subjects wore various masks of the same kind, each with a different set of clouded lenses. Visual acuities, as measured on the Snellen eye chart, were measured before, during, and after exercise. It was found that visual acuity did not influence performance time, and that an average value for a performance rating of 91 must have been influenced by other mask factors besides visual acuity. These other factors are most likely respiratory stress, thermal stress, and other vision elements. The full-facepiece masks used in this study adversely affected visual acuity by about three-quarters of a Snellen line during exercise. Postexercise visual acuities were found to first decrease below pre-exercise values, then become better than pre-exercise values, then decline asymptotically to pre-exercise values.     

The effects of hippocampal and fimbria–fornix lesions on prepulse inhibition.

The present experiments tested the effects of conventional (dorsal aspiration and electrolytic) and excitotoxic (N-methyl-{d}-aspartate [NMDA]) hippocampal lesions and fimbria-fornix (FF) transection on prepulse inhibition (PPI) of startle response and on open-field activity. Activity was increased by FF transection and by conventional but not excitotoxic hippocampal lesions; complete NMDA lesion increased amphetamine-induced activity. Whereas dorsal hippocampal aspiration lesion disrupted PPI, the phenomenon was not affected by dorsal hippocampal. electrolytic lesion, partial or complete excitotoxic (NMDA) hippocampal lesions, or complete FF transection, which interrupted the cholinergic input to the hippocampus as well as the hippocampal-subicular input to the nucleus accumbens. Systemic apomorphine disrupted PPI in both FF-transected rats and their controls. It is suggested that the hippocampus is essential for PPI disruption rather than for PPI expression. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Autonomous Vehicle Emergency Recovery Tool: A Cooperative Robotic System for Car Extraction

Vehicles have been proven to be an ideal means for terrorists because they can be meticulously prepared well in advance before being deployed in urban and public places. To increase the risk and burden of explosive ordnance disposal teams, third‐party vehicles have also been used to block the access path to the explosive loaded vehicle. In this paper, we present a multirobot system that can remove vehicles from confined spaces with delicate handling, swiftly and in any direction to a safer disposal point. The new lifting robots, capable of omnidirectional movement, autonomously underride the identified vehicle and dock to its wheels for a synchronized lifting and extraction. The validity and efficiency of the novel robotic system is illustrated via experiments in an indoor parking lot, demonstrating successful autonomous navigation, docking, lifting, and extraction of a conventional car for a total covered distance of 20 m.     

Interruption management: the use of attention-directing tactile cues

Previous research has suggested that providing informative cues about interrupting stimuli aids management of multiple tasks. However, auditory and visual cues can be ineffective in certain situations. The objective of the present study was to explore whether attention-directing tactile cues aid or interfere with performance. A two-group posttest-only randomized experiment was conducted. Sixty-one participants completed a 30-min performance session consisting of aircraft-monitoring and gauge-reading computer tasks. Tactile signals were administered to a treatment group to indicate the arrival and location of interrupting tasks. Control participants had to remember to visually check for the interrupting tasks. Participants in the treatment group responded to more interrupting tasks and responded faster than did control participants. Groups did not differ on error rates for the interrupting tasks, performance of the primary task, or subjective workload perceptions. In the context of the tasks used in the present research, tactile cues allowed participants to effectively direct attention where needed without disrupting ongoing information processing. Tactile cues should be explored in a variety of other visual, interrupt-laden environments. Potential applications exist for aviation, user-interface design, vigilance tasks, and team environments.     

Anytime measures for top-k algorithms on exact and fuzzy data sets

Top-k queries on large multi-attribute data sets are fundamental operations in information retrieval and ranking applications. In this article, we initiate research on the anytime behavior of top-k algorithms on exact and fuzzy data. In particular, given specific top-k algorithms (TA and TA-Sorted) we are interested in studying their progress toward identification of the correct result at any point during the algorithms’ execution. We adopt a probabilistic approach where we seek to report at any point of operation of the algorithm the confidence that the top-k result has been identified. Such a functionality can be a valuable asset when one is interested in reducing the runtime cost of top-k computations. We present a thorough experimental evaluation to validate our techniques using both synthetic and real data sets.     

Phase formation in electrodeposited and thermally annealed Al-Mn alloys

Aluminum-manganese alloys with compositions ranging from 0 to 50 wt pct Mn were electrodeposited onto copper substrates from a chloroaluminate molten salt electrolyte containing MnCl₂ at temperatures of 150 °C to 325 °C. The structures of these electrodeposits were then compared to those observed when metastable electrodeposits were thermally annealed at 200 °C to 610 °C. The alloys were characterized by scanning electron microscopy, transmission electron microscopy (TEM), energy dispersive spectroscopy, and X-ray diffraction. At deposition temperatures of 150 °C to 250 °C, no stable structure other than the strongly supersaturated and highly dislocated Al-face-centered cubic (fcc) solid solution is observed. An amorphous phase and body-centered cubic (bcc) Al₈Mn₅ are observed at higher manganese compositions. In the temperature range of 250 °C to 325 °C, some of the phases predicted by the equilibrium phase diagram, such as Al₆Mn and Al₁₁Mn₄, are electrodeposited. The direct deposition of the icosahedral and decagonal phases has been demonstrated at 325 °C. Thermal annealing of the amorphous phase at temperatures higher than 225 °C results in its transformation to the icosahedral phase with a grain size much smaller than that obtained in the electrodeposited icosahedral phase. Additional annealing at higher temperatures does not result in any detectable coarsening of the icosahedral phase; instead, crystals of Al₆Mn or Al₁₁Mn₄ grow into the regions once occupied by the icosahedral phase. The crystalline Al₆Mn phase which forms as the result of thermal annealing shows a structural deviation from the equilibrium phase. As-deposited alloys comprised of 2-to 3-nm-thick amorphous regions separated by fcc-Al grains failed to crystallize after 30 minutes annealing at 500 °C.