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Biomedical subjects

K S Norris

Publications and source records attributed to K S Norris.

6 recordsLinked to original sources
PubMed1969

Lizard reflectivity change and its effect on light transmission through body wall.

Light transmission through the body wall of living, color-labile desert iguanas (Dipsosaurus dorsalis) was measured by spectrophotometry. In the dark phase, the body wall's absorption of ultraviolet light and visible light was approximately twice that of the body wall in the light phase. The shorter wavelengths of ultraviolet could penetrate the body wall in the light phase but not in the dark phase. The intensity and wavelengths of light which could penetrate the body wall without pigments are potentially mutagenic when judged by bacterial standards.

Animals↗
PubMed1966

Swimming speed of a Pacific bottlenose porpoise.

Four kinds of speed runs showed a Pacific bottlenose porpoise (Tursiops gilli) to have a top speed of 29.9 kilometers per hour (16.1 knots) for 7.5 seconds and a top speed of 21.9 kilometers per hour (11.8 knots) for 50 seconds. These results compare closely with highest predictions based upon rigid body drag calculations, the same power output per unit body weight as for athletes, and a propulsive efficiency of 85 percent.

Animals↗
PubMed1966

Discriminative echolocation in a porpoise.

Operant conditioning techniques were used to establish a discriminative echolocation performance in a porpoise. Pairs of spheres of disparate diameters were presented in an under-water display, and the positions of the spheres were switched according to a scrambled sequence while the blindfolded porpoise responded on a pair of submerged response levers. Responses which identified the momentary state of the display were food-reinforced, while those which did not (errors) produced time out. Errors were then studied in relation to decreased disparity between the spheres. As disparity was decreased, errors which terminated runs of correct responses occurred more frequently and were followed by longer strings of consecutive errors. Increased errors and disruption of a stable pattern of collateral behavior were associated. Since some sources of error other than decreased disparity were present, the porpoise's final performance did not fully reflect the acuity of its echolocation channel.

Animals↗