The polar temperature of Venus

Interferometric and polarization measurements of polar regions of Venu

FM1-43 dye behaves as a permeant blocker of the hair-cell mechanotransducer channel

Hair cells in mouse cochlear cultures are selectively labeled by brief exposure to FM1-43, a styryl dye used to study endocytosis and exocytosis. Real-time confocal microscopy indicates that dye entry is rapid and via the apical surface. Cooling to 4°C and high extracellular calcium both reduce dye loading. Pretreatment with EGTA, a condition that breaks tip links and prevents mechanotransducer channel gating, abolishes subsequent dye loading in the presence of calcium. Dye loading recovers after calcium chelation with a time course similar to that described for tip-link regeneration. Myo7a mutant hair cells, which can transduce but have all mechanotransducer channels normally closed at rest, do not label with FM1-43 unless the bundles are stimulated by large excitatory stimuli. Extracellular perfusion of FM1-43 reversibly blocks mechanotransduction with half-blocking concentrations in the low micromolar range. The block is reduced by high extracellular calcium and is voltage dependent, decreasing at extreme positive and negative potentials, indicating that FM1-43 behaves as a permeant blocker of the mechanotransducer channel. The time course for the relief of block after voltage steps to extreme potentials further suggests that FM1-43 competes with other cations for binding sites within the pore of the channel. FM1-43 does not block the transducer channel from the intracellular side at concentrations that would cause complete block when applied extracellularly. Calcium chelation and FM1-43 both reduce the ototoxic effects of the aminoglycoside antibiotic neomycin sulfate, suggesting that FM1-43 and aminoglycosides enter hair cells via the same pathway

Elliptic flow of thermal dileptons in relativistic nuclear collisions

We calculate the transverse momentum and invariant mass dependence of elliptic flow of thermal dileptons for Au+Au collisions at the Relativistic Heavy Ion Collider. The system is described using hydrodynamics, with the assumption of formation of a thermalized quark-gluon plasma at some early time, followed by cooling through expansion, hadronization and decoupling. Dileptons are emitted throughout the expansion history: by annihilation of quarks and anti-quarks inthe early quark-gluon plasma stage and through a set of hadronic reactions during the late hadronic stage. The resulting differential elliptic flow exhibits a rich structure, with different dilepton mass windows providing access to different stages of the expansion history. Elliptic flow measurements for dileptons,combined with those of hadrons and direct photons, are a powerful tool for mapping the time-evolution of heavy-ion collisions.Comment: Latex 8 pages including a total of 13 postscript figures. Added 2 figures, additional references, and expanded discussions. Figures modified for better viewing. To appear in Phys. Rev.

Gender classification of face images: the role of global and feature-based information

Peer reviewe

ρ\rho meson broadening and dilepton production in heavy ion collisions

The modification of the width of the rho meson due to in-medium decays and collisions is evaluated. In high temperature and/or high density hadronic matter, the collision width is much larger than the one-loop decay width. The large width of the $\rho$ meson in matter seems to be consistent with some current interpretations of the $e^+ e^-$ mass spectra measured at the CERN/SPS.Comment: 4 pages, LaTeX, including 4 Postscript figures, to appear in Proc. of QM'99, Nucl. Phys.