We describe the geometry of geodesics on a Lorentz ellipsoid: give explicit formulas for the first integrals (pseudo-confocal coordinates), curvature, geodesically equivalent Riemannian metric, the invariant area-forms on the timeand space-like geodesics and invariant 1-form on the space of null geodesics. We prove a Poncelet-type theorem for null geodesics on the ellipsoid: if such a geodesic ...

We introduce a family of extremal polynomials associated with the prolongation of a stratified nilpotent Lie algebra. These polynomials are related to a new algebraic characterization of abnormal subriemannian geodesics in stratified nilpotent Lie groups. They satisfy a set of remarkable structure relations that are used to integrate the adjoint equations.

Localized cell shape change initiates epithelial folding, while neighboring cell invagination determines the final depth of an epithelial fold. The mechanism that controls the extent of invagination remains unknown. During Drosophila gastrulation, a higher number of cells undergo invagination to form the deep posterior dorsal fold, whereas far fewer cells become incorporated into the initially ...

Given a linear isometry A0 : Rn → Rn of finite order on Rn , a general 〈A0〉-invariant closed subset M of Rn is considered with Lipschitz boundary. Under suitable topological restrictions the existence of A0-invariant geodesics of M is proven.

[1] We have identified a dust storm deposit in the GISP2 ice core that most likely originated from the Great Plains region of the United States during the 1930’s ‘Dust Bowl’ era. These results indicate that the Central U.S. can be a significant source of dust to the Greenland ice sheet, especially when the source area is affected by intense drought conditions.

We describe a new proof of the complete integrability of the two related dynamical systems: the billiard inside the ellipsoid and the geodesic flow on the ellipsoid (in Euclidean, spherical or hyperbolic space). The proof is based on the construction of a metric on the ellipsoid whose nonparameterized geodesics coincide with those of the standard metric. This new metric is induced by the hyperb...

Evidence-based medicine has been defined as the conscientious and judicious use of current best evidence in making clinical decisions. This paper will attempt to explicate the terms “conscientious” and “judicious” within the evidence-based medicine definition. It will be argued that “conscientious” and “judicious” represent virtue terms derived from virtue ethics and virtue epistemology. The id...

...............................................................................................................v 1 The Problem of Understanding Program Behavior....................................1 2 Background: Function-Theoretic Foundations of FSQ Flow Structures..3 3 Function-Theoretic Calculation of Program Behavior ...............................6 4 The Architecture of an Abstraction Engin...

An experimental investigation was carried out to determine heat transfer coefficients for natural convection from a heated horizontal wire. The heating is provided by electrical current, and the temperature of the wire is determined from the measurement of its resistance. The experiments are performed in three different convective environments: air, water, and oil. Prandtl number ranged between...