Low-cost, broadband static phase plate for generating atmosphericlike turbulence.

Over the past decade adaptive optics (AO) has proved its worth as AO systems have been used successfully on several telescopes to improve image resolution. As scientists and engineers push the technological state of the art in an effort to make bigger, faster, and better systems, it has become more and more important to test and verify the operation of these systems in a controlled laboratory setting. To perform full-system tests in the presence of atmospheric turbulence, some sort of turbulence generator is needed. We describe a simple, low-cost approach to making static phase plates that generate atmosphericlike wave-front aberrations. These plates have several advantages over traditional heated-air turbulence generators and, as such, are better suited for well-controlled, detailed testing of an AO system.

Wave-front sensing with time-of-flight phase diversity.

We present a new way to sense atmospheric wave-front phase distortion. Short collimated pulses of laser light at ~350nm are projected from a small auxilliary telescope. Rayleigh scattering from each pulse is recorded over a wide range of height through the main telescope aperture in a continuous sequence of fast video frames by a detector conjugate to mid-height. Phase diversity is thus naturally introduced as the pulses approach and pass through focus. We show that an iterative algorithm can extract the phase structure from the recorded images and do so with a much higher signal-to-noise ratio than is possible with existing techniques. If the requirements for real-time data recording and reduction can be met, the new method will address the need for tomographic wave-front sensing at planned 30-m-class telescopes.

Halo characteristics and their influence on companion searches at the starfire optical range.

To image extrasolar planets at their large contrast, high-resolution adaptive optics (AO) is needed to correct atmospheric seeing. The 1.5-m AO system at the Starfire Optical Range was used to confirm theoretical models. Halo levels were reduced by a factor of 4, on average, from 0.5 to 3.0 arc sec radius, which when combined with the increased Strehl ratio improved the gain by a factor of 80. Speckle lifetimes ranged from 5 to 30 ms at 0.3 arc sec, which is much longer than the 0.6-ms AO update time. These results show good agreement with predictions for current technology and reveal no limitations, in principle, to the detection of planets by use of AO systems with higher speeds and resolutions.

Adaptive optics for array telescopes using piston-and-tilt wave-front sensing.

A near-infrared adaptive optics system operating at approximately 50 Hz has been used to control phase errors adaptively between two mirrors of the Multiple Mirror Telescope by stabilizing the position of the interference fringe in the combined unresolved far-field image. The resultant integrated images have angular resolutions of better than 0.1 arcsec and fringe contrasts of >0.6. Measurements of wave-front tilt have confirmed the wavelength independence of image motion. These results show that interferometric sensing of phase errors, when combined with a system for sensing the wave-front tilt of the individual telescopes, will provide a means of achieving a stable diffraction-limited focus with segmented telescopes or arrays of telescopes.

Mirror deflection on multiple axial supports.

A theoretical model based on thin plate theory is developed to calculate mirror deflection on multiple axial supports. Thickness variation due to mirror curvature, sandwich structure, and shear effects is included in this model. Comparison with the finite element analysis shows almost identical results for a three-point support. Surface deflections due to more complicated support patterns (forty-eight- and eighty-four-point support) are also included. A tolerancing model of support forces is developed and applied to the case of eight-four-point support.

Modified Pereyra procedure for stress incontinence.

Results of the modified Pereyra cystourethropexy for stress incontinence are presented. The technique prevents a suprapubic suture from entering the bladder because of a vaginal approach into the space of Retzius. The surgeon's vaginal finger guides the suprapubic needle as it passes through the rectus. Thus, a non-absorbable suture may be used and the urogenital diaphragm is brought superiorly to raise and to support the floor of the pelvis. Results are continence in 97 to 100 per cent of 30 women.

Congenital absence of penis.

A case of penile agenesis with dysplastic horseshoe kidney, bilateral ureteropelvic junction obstruction, and aganglionic megacolon is presented. Embryologic and practical considerations are discussed. We believe this to be the only known case of this congenital anomaly associated with body segmental renal dysplasia and aganglionic megacolon.

Obstructive uropathy from a cystocele.

A case is presented of bilateral hydronephrosis secondary to a lower ureteral obstruction from a cystocele. An effective method of surgical correction in a poor-risk patient is discussed.

The hydrodynamics of pyelorenal reflux. II. The effect of chronic obstructive changes on papillary shape.

Pyelotubular backflow has been shown to occur in primates at a physiologic, although somewhat higher than usual, ureteral pressure. Surgery to produce either partial ureteral obstruction or gross ureteral reflux caused a decrease in the pressure needed for pyelotubular backflow. The papilla is compliant and its shape is changed by these obstructive disorders. These findings help to explain the increased pyelonephritis associated with these abnormalities in patients.

The hydrodynamics of pyelorenal reflux.

Our study was done to determine the hydrodynamics of pyelorenal reflux. It is considered important in the pathophysiology of chronic pyelonephritis. An animal model of pyelorenal reflux was studied. The model seems to approximate closely the findings in man, both in the pressure required and the types of pyelorenal reflux observed.

The moving emission features in SS433 require a dynamical interpretation.

New spectrophotometry of SS433 shows that the variable-wavelength emission features discovered by Margon et al. are due to the simultaneous presence of material having a substantial redshift and a substantial blueshift. A magnetic interpretation for the features is also ruled out by polarimetric measurements. Implications for dynamical models are discussed.