Reflection and transmission of self-focused channels at nonlinear dielectric interfaces.

We show with an extensive numerical study that the global reflection and transmission properties of a finite-width optical self-focused channel incident at an oblique angle to an interface separating two self-focusing nonlinear media can be categorized into three distinct regimes of behavior as the incidence angle is varied through the angle for total internal reflection. The largest regime in parameter space is the nonlinear regime, where a channel undergoes either total internal reflection or transmission, in marked contrast to the well-known linear Snell's law behavior. The beam asymptotics in this latter region are quantitatively explained by a recent equivalent-particle theory.

Age, sex, ethnic origin and tonsillectomy.

The age-related sex ratios for patients undergoing adenotonsillectomy and tonsillectomy have been calculated in different populations. Differences in these sex ratios have been found at different ages, and differences between populations have also been found. Various reasons are proposed to account for these findings.

Regional choroidal atrophy and alopecia. A new syndrome.

Two siblings with total regional choroidal atrophy and other manifestations of ectodermal dysplasia are presented. The mode of inheritance is uncertain, but mild macular disease in the father may represent heterozygote manifestation of a recessive condition.

Linkage analysis of X linked retinitis pigmentosa in the Irish population.

There is significant evidence for genetic and phenotypic heterogeneity in X linked retinitis pigmentosa (XLRP). We have studied the linkage of XLRP in four Irish families to a number of polymorphic DNA markers. We report linkage between the DXS7 (L1.

Two year electrophysiology follow-up in quinine amblyopia. A case report.

A 19-year-old girl presenting with quinine amblyopia had serial electrophysiology studies over a 2 year period. Visually evoked responses and the electro-oculogram were abolished early. By 2 months the VER and visual acuity had returned to normal.

The acute orbit. Preseptal (periorbital) cellulitis, subperiosteal abscess and orbital cellulitis due to sinusitis.

The clinical picture of an acute orbit, as manifest by preseptal cellulitis, subperiosteal abscess or orbital cellulitis, is still frequently seen in ENT practice. The commonest cause is sinusitis and the authors advocate early surgical intervention in acute orbits due to sinusitis. Clinically, it can be difficult to distinguish between a subperiosteal abscess and orbital cellulitis and a CAT scan may be helpful.

Beam-propagation method analysis of a nonlinear directional coupler.

The beam-propagation method is employed to analyze nonlinear directional-coupler operation for various combinations nonlinear materials and initially mismatched guides. A mixed focusing-defocusing configuration is found optimal results.

The diffusion of water across the stratum corneum as a function of its water content.

The flux of tritiated water (HTO) through pieces of stratum corneum at four different levels of hydration has been measured. The concentration of water in the stratum corneum, the concentration of HTO in the presenting solution, and the thickness, density, and weight per unit area of the dry stratum corneum are known. The thickness of the hydrated stratum corneum and the permeability and diffusion constants of HTO were calculated.

Retinal function in Stargardt's disease and fundus flavimaculatus.

Ten patients with Stargardt's disease and 14 with fundus flavimaculatus underwent thorough ophthalmic examinations, retinal photography, and, when possible, fluorescein angiography. Retinal function was also assessed by static and kinetic perimetry, the Farnsworth-Munsell 100-hue test, electro-oculography, and electroretinography. Visual acuity and color discrimination were reduced in all patients (mean visual acuity, 20/120; mean error score, 365).