Entorhinal cortex layer II stellate cells display subthreshold oscillations (STOs). We study a single compartment biophysical model of such cells which qualitatively reproduces these STOs. We argue that in the interspike interval (ISI) the seven-dimensional model can be reduced to a three-dimensional system of equations with well differentiated times scales. Using dynamical systems arguments we...

The peculiar head morphology of hammerhead sharks has spawned a variety of untested functional hypotheses. One of the most intuitively appealing ideas is that the anterior foil acts, as in canard-winged aircraft, to increase maneuverability. We tested this hypothesis by determining whether juveniles of two hammerhead species (Sphyrna tiburo and S. lewini) turn more sharply, more often, and with...

The aerodynamic loads on a Canard Rotor/Wing vehicle are investigated using inviscid numerical simulations in order to understand the flight characteristics of the vehicle during conversion from rotary to fixed-wing flight. A series of numerical simulations at seven azimuthal rotor indices are presented covering a quarter turn of the rotor. With symmetry arguments, these simulations produce 25 ...

Pituitary cells of the anterior pituitary gland secrete hormones in response to patterns of electrical activity. Several types of pituitary cells produce short bursts of electrical activity which are more effective than single spikes in evoking hormone release. These bursts, called pseudo-plateau bursts, are unlike bursts studied mathematically in neurons (plateau bursting) and the standard fas...

We explore the bifurcations and dynamics of a scalar differential equation with a single constant delay which models the population of human hematopoietic stem cells in the bone marrow. One parameter continuation reveals that with a delay of just a few days, stable periodic dynamics can be generated of all periods from about one week up to one decade! The long period orbits seem to be generated...

The blood parasite Leucocytozoon simondi is often associated with heavy mortality of ducks and geese, especially domestic ones, in North America. In contrast, in a previous study we found no mortality from L. simondi in our wild stock of mallard (Anas platyrhynchos) and American black duck (Anas rubripes) ducklings. However, because parasites can slow growth, which could extend the interval dur...