Critical velocities have been observed in an ultracold superfluid Fermi gas throughout the BEC-BCS crossover. A pronounced peak of the critical velocity at unitarity demonstrates that superfluidity is most robust for resonant atomic interactions. Critical velocities were determined from the abrupt onset of dissipation when the velocity of a moving one-dimensional optical lattice was varied. The...

Although pressure elevation in lung postcapillary venules increases endothelial P-selectin expression, the extent to which P-selectin causes lung leukocyte margination remains controversial. To address this issue, we optically viewed postcapillary venules of the isolated blood-perfused rat lung by real-time fluorescence imaging. To determine leukocyte margination in single postcapillary venules...

BACKGROUND AND PURPOSE Transcranial Doppler measurements of blood flow velocity permit an assessment of variations in intracranial hemodynamics in response to acute arterial pressure variations. The purpose of this study was to scan healthy volunteers and patients with autonomic failure for differences in cerebral hemodynamic patterns under an acute hypotensive stimulus. METHODS We used trans...

Transient changes in arterial diameter in response to transient ischemia-induced changes in arterial blood velocity have been used as an index of vascular health. The purpose of this study was to determine the relationship between blood velocity and diameter in the brachial artery by different methods of increasing blood velocity. Acute cigarette smoking was used with otherwise healthy young oc...