This paper uses geometric methods to study basic problems in the mechanics and control of locomotion. We consider in detail the case of \undulatory locomotion," in which net motion is generated by coupling internal shape changes with external nonholonomic constraints. Such locomotion problems have a natural geometric interpretation as a connection on a principal ber bundle. The properties of co...

Undulatory motion of the body is the dominant mode of locomotion in fishes, and numerous studies of body kinematics and muscle activity patterns have provided insights into the mechanics of swimming. However, it has not been possible to investigate how key parameters such as the extent of bilateral muscle activation affect propulsive performance due to the inability to manipulate muscle activat...

a detailed study of ostracoda changes against the stable isotopes of carbon and oxygen acrossthe cenomanian-turonian boundary mass extinction has been fully documented in one section, the south ofengland. this section comprises the uppermost cenomanian to lowermost turonian strata. the comparisonbetween the results obtained in this research and two rival models for the cenomanian-turonian bound...

About 35 samples were collected from lower and upper parts of the proposed Frasnianamennian boundary in three sections of Upper Devonian marine sediments of the Kerman province. The biostratigraphical and geochemical studies indicate that about 45% extinction of brachiopods probably caused by the Frasnian-Famennian bioevents, which is slightly higher than thr rate of Devonian-Carboniferous exti...

The purpose of this study was to investigate the mechanical control of speed in steady undulatory swimming. The roles of body flexural stiffness, driving frequency and driving amplitude were examined; these variables were chosen because of their importance in vibration theory and their hypothesized functions in undulatory swimming. Using a mold of a pumpkinseed sunfish Lepomis gibbosus, we cast...

The startle response is a model system for examining the neural basis of behavior because of its relatively simple neural circuit organization and kinematic pattern. In fishes, the two primary types of startle behavior differ in their initial movements. In the C-start type of startle, the fish bends into a C shape, while the S-start involves an S-shaped body bend. Although considerable research...