PubMed Health⌕ Search

Biomedical subjects

R Kruk

Publications and source records attributed to R Kruk.

7 recordsLinked to original sources
PubMed1998

[The medical profession in the medieval Arabic conversation].

In the medieval Arabic culture the medical profession was discussed in several ways. Major themes were: the image of the physician with strong roots in the Greek medical ethics; the rivalry between physicians often showing itself in the accusation of quackery; the competition with paramedics; the stupidity or unwillingness of patients; the medical success story in which the physician has almost super natural powers. Most of these elements are discussed along with the history of a famous family of physicians, the Bukhtishu, who served as court-physicians to many of the Abbasidic caliphs.

Arab World↗
PubMed1996

Collision avoidance: a helicopter simulator study.

METHOD: Six pilots flew a helicopter flight simulator with a helmet-mounted display. The pilot's task was to judge the time to collision with a second helicopter that disappeared at either 2, 2.5, or 3 s before collision. The field of view (FOV) was 66 degrees (vertical) x 127 degrees or 19 degrees x 25 degrees or 3 degrees x 3 degrees. RESULTS: With a stationary target and ownship forward speed of 60 kt, pilots estimated that collision with a stationary target would occur roughly 200 ms before the actual time to collision in the large and intermediate FOV conditions. In the case of ownship stationary and the target approaching at 60 kt, estimates of collision time showed considerably less lead in the large and intermediate FOV conditions. When the smallest FOV was used, estimates were the same whether closing speed was produced entirely by ownship motion or entirely by target motion. CONCLUSION: We suggest that the too-early errors in estimating time to collision were caused by the impression of self-motion produced by stimulating the peripheral retina with a radially-expanding flow pattern.

Accident Prevention↗
PubMed1983

Visual test results compared with flying performance in telemetry-tracked aircraft.

We compared flying performance with the results of laboratory and airborne visual tests. Pilots flew high-performance, telemetry-tracked A4 and F-14 aircraft. In the low-level task, the index of performance was bombing accuracy; in air-to-air combat, performance was assessed by the number of missile hits scored per hit received (win/loss ratio). The chief laboratory tests comprised discrimination between two speeds of a radially-expanding flow pattern, and manual tracking of a visual target. Airborne tests comprised visual acquisition distance of an A4 aircraft, and visual sensitivity to a change in the course of an approaching A4 aircraft. We found that the flow pattern and movement-in-depth tracking test results correlated with bombing accuracy, confirming previously reported simulator findings. The results of airborne visual tests correlated with the win/loss ratio in combat, and tracking test results correlated with the number of missiles fired per combat engagement. Subsidiary tests of motion, grating contrast, and visual acuity thresholds were carried out for comparability with other studies, but these measures did not predict flying performance.

Adult↗
PubMed1981

Correlations between visual test results and flying performance on the advanced simulator for pilot training (ASPT).

Looking for visual differences in pilots to account for differences in flying performance, we tested five groups of subjects: Air Force primary student jet pilots, graduating (T38 aircraft) students, Air Force pilot instructors, and two control groups made up of experienced nonpilot aircrew and nonflying civilians. This interim report compares 13 different visual test results with low-visibility landing performance on the Air Force Human Resources Laboratory ASPT simulator. Performance was assessed by the number of crashes and by the distance of the aircraft from the runway threshold at the time of the first visual flight correction. Our main finding was that, for student pilots, landing performance correlated with tracking performance for a target that changed size (as if moving in depth) and also with tracking performance for a target that moved sideways. On the other hand, landing performance correlated comparatively weakly with psychophysical thresholds for motion and contrast. For student pilots, several of the visual tests gave results that correlated with flying grades in T37 and T38 jet aircraft. Tracking tests clearly distinguished between the nonflying group and all the flying groups. On the other hand, visual threshold tests did not distinguish between nonflying and flying groups except for grating contrast, which distinguished between the nonflying group and the pilot instructors. The sideways-motion tracking task was sensitive enough to distinguish between the various flying groups.

Adult↗