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Biomedical subjects

L C Boer

Publications and source records attributed to L C Boer.

8 recordsLinked to original sources
PubMed2004

Auditory guidance in a smoke-filled tunnel.

As a test on auditory guidance, participants tried to find refuge and safety in a road tunnel in dense smoke with sound beacons over the escape exits. The beacons emitted a 'shhussing' noise with a 5-Hz pulse frequency. Three groups participated, 32 or 33 participants per group, the first with minimal instruction (sound not mentioned), the second with beacons instruction 'sound beacons help you to orient', and the third with full instruction 'sound beacons over the escape exits'. The percentage of participants finding an escape exit was 16, 21, and 70%, respectively. While the potential of auditory guidance is amply demonstrated, there is the possibility that improvement in the recognition of the sound could improve escape exit usage further. It is recommended to include in the sound of the beacon the speech fragment 'exit here'. This will probably eliminate the need for instruction. If, in the future, the beacons are used broadly (in buildings, on ships and planes), the recognition issue should diminish.

Confined Spaces↗
PubMed1997

The selective-listening task as a test for pilots and air traffic controllers.

This study evaluates the selective-listening task (SLT) originally developed by Gopher and Kahneman (1971). A brief analysis of the abilities measured by the SLT is presented, and investigations involving Royal Netherlands Air Force aviator applicants and Royal Netherlands Navy air traffic control applicants are reported. Task performance of samples from both populations (N=175 and N=87, respectively) correlated significantly with subsequent pass-fail in training (r=.34). Incremental validity of the SLT is demonstrated by (a) the absence of significant correlations with other operational selection tests and (b) a multiple regression analysis showing that the SLT explained a significant amount of residual variance not explained by the existing operational tests. We conclude that the SLT increases the assessment potential of an existing selection battery. However, we recommend simplifying the scoring procedure and suggest ways to increase the validity.

Adolescent↗
PubMed1996

Influence of a carbohydrate drink on performance of military personnel in NBC protective clothing.

BACKGROUND: The increased threat of nuclear, biological and chemical (NBC) weapons underlines the need of protective clothing and gas masks, but this may impair performance. Thus, attention should be focused on the nutritional requirements. HYPOTHESIS: Optimal performance is guaranteed if the supply of water and energy is adequate. METHODS: Two groups of 20 trained military men (mean age 22 yr) received either an isotonic carbohydrate drink or a placebo drink (flavored water) for 24 h under simulated NBC conditions (wearing gas masks and protective clothing). Various physical and mental tests were performed at intervals and blood samples were collected three times. RESULTS: Five men of the placebo group had to be withdrawn during the experiment because of exhaustion. The decrease in physical performance (about 15%) and mental performance (about 20%) was most apparent for the group that had only water for consumption. CONCLUSIONS: When only water is consumed, physical performance of a group of military men decreases during 24 h of simulated NBC conditions. An isotonic carbohydrate drink is recommended with respect to maintaining performance under NBC conditions. Energy restriction prior to an NBC scenario has a negative influence on performance.

Administration, Oral↗
PubMed1991

Mental rotation in perspective problems.

The present paper demonstrates that mental rotation as used in the processing of disoriented objects (Cooper and Shepard 1973) can also be used as an explanatory concept for the processing of perspective problems in which the task is to imagine how an environment will appear from another vantage point. In a cognitive map, subjects imagined an initial line of vision and subsequently processed a reorientation stimulus, requesting them to imagine a turn over 0, 45, 90, 135, or 180 degrees. Time for a reorientation increased linearly with the size of the imaginary turn up to 135 degrees and decreased for turns of 180 degrees; apparently, about-faces were relatively easy to imagine. The increment of reorientation time between 0 and 135 degrees was larger for maps presented in unfamiliar orientations such as South-West up. Both the increment and the interaction with familiarity are consistent with an explanation in terms of mental rotation.

Adult↗