Virus surveillance in free-flying, nonmigratory ducks living on the eastern shore of Maryland indicated that influenza A viruses were introduced into the area or that the prevalence of endemic infections increased between July 15 and August 27, 1998. Cloacal swabs collected between May 28 and July 15, 1998, were negative for influenza A virus recovery (0/233), whereas 13.9% (29/209) of swabs co...

Over the past two decades, there has been a growing interest in developing predictive models of animal movement and force generation in fluids. In a departure from past studies that have asked how prescribed motions of a propulsor (wing or fin) generate lift and thrust during swimming and flying, we are increasingly interested in predicting the propulsor's movement as well as the forces generat...

The locomotor controller for walking, running, swimming, and flying animals is based on a Central Pattern Generator (CPG). Models of CPGs as systems of coupled non-linear oscillators have been proposed and have been used for the control of robots. In this paper we describe the implementation of an adaptive CPG model in a compact, custom analog VLSI circuit. We demonstrate the function of the ch...

experimental infection of muscovy ducks with v4 strain of newcastle disease virus was undertaken to determine the response of the ducks to the virus and the possibility of virus transmission to ducks and chickens in village like conditions. twelve ducks were randomly and equally divided into three groups of control, inoculated and in-contact. additionally, the chickens were placed into two grou...

A mechanical model of swimming and flying in an incompressible viscous fluid in the absence of gravity is studied on the basis of assumed equations of motion. The system is modeled as an assembly of rigid spheres subject to elastic direct interactions and to periodic actuating forces which sum to zero. Hydrodynamic interactions are taken into account in the virtual mass matrix and in the fricti...

Swimming and flying animals generate unsteady locomotive forces by delivering net momentum into the fluid wake. Hence, swimming and flying forces can be quantified by measuring the momentum of animal wakes. A recently developed model provides an approach to empirically deduce swimming and flying forces based on the measurement of velocity and vortex added-mass in the animal wake. The model is c...