Description of readout processes during strong beam coupling.

We show, using the symmetry properties of the coupled-wave equations for the transmission and reflection geometries, that any readout characteristic of dynamic spatially nonuniform index gratings in photorefractive crystals can be explicitly expressed through the characteristics of the recording light beams. This approach is applied to describe the impact of beam coupling on the diffraction efficiency of dynamic gratings and on the output intensities of the light beams at instantaneous input phase changes (light grating translation). Further implications of this general approach are discussed.

Holographic face models as planning tool in maxillofacial surgery.

The holographic facial profile scan is a new technique for creation of high-resolution, three-dimensional, realistic facial computer models which can be used for surgical planning and documentation in maxillofacial surgery. First, a holographic image of the patient is recorded using a pulsed laser system. In a second step, called holographic tomography, the real image of the patient's hologram is reconstructed by means of a continuous-wave laser. By moving a screen through the real three-dimensional image, it is sliced into a series of two-dimensional projections which are captured with a digital camera. The slices containing the specific two-dimensional information are superimposed to a three-dimensional surface model using special software. The extremely short exposure time of 35 nanoseconds for taking a holographic image is separated from the time-consuming rendering process of the surface model; thus, the obtained models are not affected by the movements of the patient.

Diffusion of Cs atoms in Ne buffer gas measured by optical magnetic resonance tomography.

Optical magnetic resonance tomography uses optical pumping and the paramagnetic Faraday effect to image spin density distributions in optically thin media. In this paper we present an apparatus that allows to measure the distribution of spin-polarized Cs atoms, which we applied to study the diffusion of Cs in Ne buffer gas by time-resolved 2D-mapping of the evolution of an initial inhomogeneous spin distribution. The diffusion constant D0 for Cs in a Ne buffer gas of 1013 mbar is determined as 0.20(1) cm2\s.

A selected review of the physics of radiation therapy.

This article covers some of the basic physics needed to understand and plan radiation therapy. Special attention is given to those issues that are more common in veterinary radiation oncology. Far greater depth of discussion and explanation may be found in many standard texts and should be used for specific information and situations.

Is Sports Medicine Hampered by Cost Containment?

Most sports medicine physicians are affected in some way by the multitude of HMOs and PPOs that have sprung up nationwide. Some have welcomed the patients and the assured payments these organizations bring. Others say these plans have interfered with medical care and have stunted innovation in sports medicine.

Freestyle Skiing: From 'Hotdogging' to Olympic Demonstration Event.

Once associated primarily with dangerous aerial maneuvers, freestyle skiing has undergone many changes in training, certification, and safety, and will be a demonstration event at the 1988 Olympic Winter Games in Calgary.

Women's Weight Lifting: Elevating a Sport to World-Class Status.

The first women's world weight-lifting competition-held last fall in Daytona Beach, Florida-is evidence that the sport is growing and building its case for Olympic medal status. But little is known about the medical aspects of weight lifting for women.