Results of transport measurements on a GaAs quantum dot are presented in which the gate geometry allows the dot to be accessed by three, rather than two, contacts. In the Coulomb blockade regime, conductance oscillations periodic in gate voltage are measured concurrently at two contacts in response to a small excitation voltage at the third contact. When the dot is in the strongly blockaded regime, we obtain the expected result from single electron tunneling theory that oscillations at the two output contacts are correlated with each other in gate voltage. As the tunnel barriers are made softer by changing the gate voltage, a strikingly different phenomenon is observed: conductance peaks at the two output leads evolve from perfect correlation to perfect anticorrelation with each other.

We compare the transmission through static defects in an electron waveguide with the scattering from a one-dimensional potential barrier which oscillates in time. The multiple spatial 'subband' conduction channels in the waveguide, and multiple energy 'sideband' channels for the oscillator, produce transmission resonances near the 'bound' and 'quasi-bound' states in these potentials. Additional novel transmission behavior in a highly disordered waveguide arises from the interplay of electron localization with the confinement subbands.

The tunneling conductance of junctions formed on thin films of Al in contact with films of the ferromagnetic semiconductor EuO implies that such composites behave like BCS superconductors with internal magnetization. In a magnetic field $B$ applied in the plane of the films, the superconducting quasiparticle density of states shows a splitting $2\ensuremath{\mu}({B}^{*}+B)$, where ${B}^{*}$ can be greater than $B$ by more than a tesla. The critcal field of composite films is reduced by approximately ${B}^{*}$ compared to that of identical Al films without EuO. The observed ${B}^{*}$ is of the same magnitude as $\ensuremath{\mu}_{0}M$, the magnetization of EuO.