Sensitivity of neurons in the torus semicircularis of a weakly electric fish, Gymnarchus niloticus, to two stimulus parameters that are critical for its behavior the jamming avoidance response was examined. The first parameter is the sign of frequency difference between discharge frequencies of fish's own electric organ and that of a neighbor's. The second parameter is the spatial orientation o...

We report the observation of sum-frequency signals that depend linearly on an applied electrostatic field and that change sign with the handedness of an optically active solute. This recently predicted chiral electro-optic effect exists in the electric-dipole approximation. The static electric field gives rise to an electric-field-induced sum-frequency signal (an achiral third-order process) th...

Field Due to an Electric Dipole An electric dipole consists of two particles with charges of equal magnitude q but opposite sign, separated by a small distance d. Their electric dipole moment has magnitude qd and points from the negative charge to the positive charge. The magnitude of the electric field set up by the dipole at a distant point on the dipole axis (which runs through both charges) is

In this paper, the scattering of a plane monochromatic electromagnetic wave from a nanowire with circular cross-section in the transverse electric (TE) mode is simulated using the well-known Stratton-Chu surface integral equations. For an ordinary dielectric nanowire the refraction phenomenon is nicely simulated. In the case of a plasmonic nanowire no sign of surface plasmon excitation and prop...

The jamming avoidance response of the weakly electric fish Gymnarchus niloticus relies on determining the sign of the frequency difference (Df) between the fish's own electric organ discharge (EOD) and that of a neighbor, which is achieved by comparing modulations in amplitude (AM) and phase (PM) that result from the summation of their EODs. These two stimulus features are processed in separate...

We show that the Landau levels cease to be eigenvalues if we perturb the 2D Schrödinger operator with constant magnetic field, by bounded electric potentials of fixed sign. We also show that, if the perturbation is not of fixed sign, then any Landau level may be an eigenvalue of the perturbed problem. AMS 2000 Mathematics Subject Classification: 35J10, 81Q10, 35P20

We show that the Landau levels cease to be eigenvalues if we perturb the 2D Schrödinger operator with constant magnetic field, by bounded electric potentials of fixed sign. We also show that, if the perturbation is not of fixed sign, then any Landau level may be an eigenvalue of the perturbed problem. AMS 2000 Mathematics Subject Classification: 35J10, 81Q10, 35P20

Lhermitte's sign (LS) or 'Baber's chair sign' consists of a sudden electric shock-like sensation that shoots down the back and into the limbs when the neck is flexed. In patients with cancer, LS has been associated with spinal cord involvement, postirradiation phenomenon, and chemotherapy:

Central sensory neurons often respond selectively to particular combinations of stimulus attributes, but we know little about the underlying cellular mechanisms. The weakly electric fish Gymnarchus discriminates the sign of the frequency difference (Df) between a neighbor's electric organ discharge (EOD) and its own EOD by comparing temporal patterns of amplitude modulation (AM) and phase modul...