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B N Walker

Publications and source records attributed to B N Walker.

7 recordsLinked to original sources

Pitch and pitch change interact in auditory displays.

Designing auditory displays requires understanding how different attributes of sound are processed. Operators must often listen to a particular stimulus dimension and make control actions contingent on the auditory information. Three experiments used a selective-listening paradigm to examine interactions between auditory dimensions. Participants were instructed to attend to either relative pitch or direction of pitch change of dynamic stimuli. With vertically arranged keypress responses, reactions to both dimensions showed stimulus-response compatibility effects, indicating that pitch is treated spatially. Direction of pitch change affected responses to pitch; level of pitch more strongly affected responses to pitch change. To reduce deleterious effects of irrelevant pitch information, auditory display designers can restrict the pitch range used to display dynamic data.

Adult↗

Enamel cracks. The role of enamel lamellae in caries initiation.

Lamellae or cracks are distributed throughout tooth enamel in both deciduous and permanent dentitions. While earlier authors postulated that lamellae may be pathways of entry for caries, no evidence was adduced and the theory appears to have been discounted. The present study seeks to show that, at least in some cases, lamellae are permeable to dyes, may be associated with caries initiated in the dentine, supporting the hypothesis of Hardwick and Manly of lamellae penetration by Streptococcus mutans and lactobacilli. The enamel lamellae are shown to be a permeable pathway allowing caries-producing bacteria access to the dentine-enamel junction. Caries can thus be established within the tooth without visible evidence at the surface.

Azo Compounds↗

Attitude of dentists.

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Attitude of Health Personnel↗