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Behavioral Effects Of Tyrosine During Sustained Wakefulness, D. L. Wiegmann, D. F. Neri, R. R. Stanny, S. A. Shappell, A. H. Mccardie, D. L. Mckay

Publications

The fatigue and cognitive performance deficits associated with sleep loss and stress, like that experienced during sustained flight operations and nighttime flying, have motivated the search for effective nonpharmacological countermeasures. The behavioral effects of the potential countermeasure tyrosine, an amino-acid precursor to dopamine and norepinephrine, were examined during an episode of continuous nighttime work involving one night's sleep loss. Volunteers performed nine iterations of a battery of cognitive and subjective tasks for approximately 13 h, beginning at 1930 and ending at 0820 the following morning. Subjects remained awake throughout the day on which the experiment began and were awake for …

Gravity Wave-Driven Fluctuations In The O2 Atmospheric (0-1) Nightglow From An Extended, Dissipative Emission Region, Michael P. Hickey Ph.D., G. Schubert, R. L. Walterscheid

Publications

The wave-driven fluctuations in the O2(0-1) atmospheric nightglow is modeled and the parameter (eta) is calculated using a model that accounts for either three-body recombination of atomic oxygen atoms alone to form the O2(b exp 1 Sigma(g)(+)) state directly, or by the further inclusion of the process that allows the formation of the O2(c exp 1 Sigma(u)(-)) intermediate state. The calculations are performed for a latitude of 18 deg N and for the months of March and June. The general results, which display how (eta) varies with wave period, horizontal wavelength, season, and chemical scheme, show that for given values …

The Effects Of Luminance Boundaries On Color Perception, Richard E. Kronauer, Charles F. Stromeyer Iii, Alex Chaparro

Publications

The luminance and red-green chromatic detection mechanisms respond to, respectively, the sum and difference of the long-wave (L) and middle-wave (M) zone contrast signals. The most-detectable stimulus is not a small patch of luminance drifting grating, as suggested by others, but rather a small, foveal red-green chromatic flash. Even at the smallest test size examined, 2.3' diameter, the red-green mechanism i~s more sensitive than the luminance mechanism, which has profound implication for visual physiology. When a suprathreshold luminance flash (a pedestal) occurs coincidentally with a red-green chromatic flash, detection of color is facilitated ~2-fold, regardless of spot size, as shown …

An Alternative Representation Of The Ice Canopy For Calculating Microwave Brightness Temperatures Over A Thunderstorm, Bradley M. Muller, Henry E. Fuelberg, Eric A. Smith

Publications

Passive microwave brightness temperatures (T(B)'s) at 92 and 183 GHz from an aircraft thunderstorm overflight are compared with values calculated from radar-derived hydrometeor profiles and a modified proximity sounding. Two methods for modeling particles in the ice canopy are contrasted. The first is a ''traditional'' approach employing Marshall-Palmer ice spheres. The second, or ''alternative,'' method partitions 20% of the ice water content into a Marshall-Palmer component for graupel and hail, and 80% into a modified gamma spherical particle size distribution function representing ice crystals.

Results from the alternative approach are superior to those from the traditional method in the anvil …

Work/Rest Schedules And Performance Of F/A-18 Aviators During Fleet Exercise 1992, Scott A. Shappell, David F. Neri

Publications

As a continuation of our previous work during Operation Desert Shield/Storm, we examined the effect a fleet exercise has on the work/rest patterns, fatigue, and cognitive performance of F/A-18 aviators. For 10 days during Fleet Exercise 1992, 25 pilots from VFA-81 and VFA-83 completed daily work/rest logs while performing their usual tasks. Subjective measure of fatigue, quality of rest, and sleep need were also collected. A subset of these F/A-18 pilots completed a brief battery of cognitive tasks as soon before flying as possible and again after the flight debrief. As a group, the pilots were adequately rested with little …

Work/Rest Schedules And Performance Of S-3 Aviators During Fleet Exercise 1992, David F. Neri, Scott A. Shappell

Publications

We examined the effect that a fleet exercise has on the work/rest patterns, fatigue, and cognitive performance of S-3 aviators. For 10 days during Fleet Exercise 1992, 21 S-3 aviators from CARRIER AIR WING SEVENTEEN (CVW-17) aboard USS SARATOGA (CV-60) completed detailed daily-activity logs while performing their usual tasks. Subjective measures of fatigue, quality of rest, and sleep need were also collected. A subset of eight aviators completed a brief battery of computer tasks as soon before flying as possible and again after flight debrief. Results indicated that, although the fleet exercise appeared to be below average in difficulty, there …