Symmetric non-expanding horizons

Expanding horizons

Colchicine--expanding horizons.

To say that the once very limited indications for colchicine have undergone a subtle but definite and dramatic change in recent years would not be an overstatement. This old drug, which has been known for centuries, was used for relieving and preventing acute attacks of gouty arthritis for over 200 years, but until recently, no other clinical uses had been established. The 1985 edition of Good-...

Expanding cerebellar horizons.

Anatomical connections must underly neuronal function. A new study by Middleton and Strick shows that the cerebellum projects to the dorsal prefrontal cortex of the monkey. This could provide the basis for cerebellar modulation of cognitive processes.

Geometry of Non-expanding Horizons and Their Neighborhoods

This is a contribution to MG9 session BHT4. Certain geometrically distinguished frame on a non-expanding horizon and in its space-time neighborhood, as well as the Bondi-like coordinates are constructed. The construction provides free degrees of freedom, invariants, and the existence conditions for a Killing vector field. The reported results come from the joint works with Ashtekar and Beetle [...

Vacuum Non-Expanding Horizons and Shear-Free Null Geodesic Congruences

We investigate the geometry of a particular class of null surfaces in space-time called vacuum Non-Expanding Horizons (NEHs). Using the spin-coefficient equation, we provide a complete description of the horizon geometry, as well as fixing a canonical choice of null tetrad and coordinates on a NEH. By looking for particular classes of null geodesic congruences which live exterior to NEHs but ha...