Dissociation and the development of spatial correlation in a molecular ultracold plasma.

Penning ionization initiates the evolution of a dense molecular Rydberg gas to plasma. This process selects for pairs of excited molecules separated by a distance of two Rydberg orbital diameters or less. The deactivated Penning partners predissociate, depleting the leading edge of the distribution of nearest-neighbor distances.

Observation of a resonant four-body interaction in cold cesium Rydberg atoms.

Cold Rydberg atoms subject to long-range dipole-dipole interactions represent a particularly interesting system for exploring few-body interactions and probing the transition from 2-body physics to the many-body regime. In this work we report the direct observation of a resonant 4-body Rydberg interaction. We exploit the occurrence of an accidental quasicoincidence of a 2-body and a 4-body resonant Stark-tuned Förster process in cesium to observe a resonant energy transfer requiring the simultaneous interaction of at least four neighboring atoms.

Kilohertz dye laser system for high resolution laser spectroscopy.

We have electro-optically sliced the output light of a commercial Coherent Evolution Nd:YLF laser to pump a kilohertz repetition rate nanosecond dye laser system. Simple and highly adjustable, this laser system can easily be used for initial state preparation for ultrafast systems as well as high resolution spectroscopy.

Nondispersing Bohr wave packets.

Long-lived, nondispersing circular, or Bohr, wave packets are produced starting from Li Rydberg atoms by exposing them first to a linearly polarized microwave field at the orbital frequency, 17.6 GHz at principal quantum number n=72, which locks the electron's motion into an approximately linear orbit in which the electron oscillates in phase with the microwave field. The microwave polarization is changed to circular polarization slowly compared to the orbital frequency, and the electron's motion follows, resulting in a nondispersing Bohr wave packet.

Urokinase treatment of sagittal sinus thrombosis with venous hemorrhagic infarction.

Background: Selective catheterization of the dural venous sinuses with local infusion of urokinase may be beneficial in patients with venous sinus thrombosis, and has been reported to be safe in patients with venous infarction. However, information regarding safety in the presence of hemorrhage is sparse.

Methods: Three patients presented with severe, progressive focal neurological symptoms (National Institutes of Health Stroke Scales: 14, 22, and 12) resulting from superior sagittal sinus thrombosis, with evidence of hemorrhage on computed tomographic scans (two intraparenchymal, one subarachnoid).