Topological asymmetry in the damping-pairing contribution of electron-boson scattering

We make a harmonic analysis of the pairing and damping contribution of a finite $k$ range isotropic electron-phonon (or other boson) scattering in an anisotropic two-dimensional electronic system. We show that the pairing contribution of the anisotropic part of the electronic system can be much larger than its damping contribution enhancing significantly T_c. The higher is the order of the harmonic of the electronic anisotropy, smaller is its damping contribution and higher can be the asymmetry in its damping-pairing contribution. This could explain the puzzle of a much broader quasiparticle peak in the n-doped than in the p-doped cuprates, their smaller T_c's being also attributed to larger damping effects.Comment: LATEX file and 3 Postscript figure

Alignment positioning mechanism

An alignment positioning mechanism for correcting and compensating for misalignment of structures to be coupled is disclosed. The mechanism comprises a power screw with a base portion and a threaded shank portion. A mounting fixture is provided for rigidly coupling said base portion to the mounting interface of a supporting structure with the axis of the screw perpendicular thereto. A traveling ball nut threaded on the power screw is formed with an external annular arcuate surface configured in the form of a spherical segment and enclosed by a ball nut housing with a conforming arcuate surface for permitting gimballed motion thereon. The ball nut housing is provided with a mounting surface which is positionable in cooperable engagement with the mounting interface of a primary structure to be coupled to the supporting structure. Cooperative means are provided on the ball nut and ball nut housing, respectively, for positioning the ball nut and ball nut housing in relative gimballed position within a predetermined range of relative angular relationship whereby severe structural stresses due to unequal loadings and undesirable bending moments on the mechanism are avoided

Mass Media and Environmental Risk: Seven Principles

Dr. Sandman suggests that, when spokespersons for risk sources are inept in conveying their messages, they and we pay heavily for their mistakes