Wavefront sensing of atmospheric phase distortions at the Palomar 200-in. telescope and implications for adaptive optics

Major efforts in astronomical instrumentation are now being made to apply the techniques of adaptive optics to the correction of phase distortions induced by the turbulent atmosphere and by quasi-static aberrations in telescopes themselves. Despite decades of study, the problem of atmospheric turbulence is still only partially understood. We have obtained video-rate (30 Hz) imaging of stellar clusters and of single-star phase distortions over the pupil of the 200" Hale telescope on Palomar Mountain. These data show complex temporal and spatial behavior, with multiple components arising at a number of scale heights in the atmosphere; we hope to quantify this behavior to ensure the feasibility of adaptive optics at the Observatory. We have implemented different wavefront sensing techniques to measure aperture phase in wavefronts from single stars, including the classical Foucault test, which measures the local gradient of phase, and the recently-devised curvature sensing technique, which measures the second derivative of pupil phase and has formed the real-time wavefront sensor for some very productive astronomical adaptive optics. Our data, though not fast enough to capture all details of atmospheric phase fluctuations, provide important information regarding the capabilities that must be met by the adaptive optics system now being built for the 200" telescope by a team at the Jet Propulsion Lab. We describe our data acquisition techniques, initial results from efforts to characterize the properties of the turbulent atmosphere at Palomar Mountain, and future plans to extract additional quantitative parameters of use for adaptive optics performance predictions

Switching Focus of Attention Mid-trial and its Effect on Stability During a Balance Task

For more than a decade focus of attention studies have shown an external focus is superior for performance compared to an internal focus of attention. The constrained action hypothesis suggests this occurs because an external focus of attention allows movement to happen more autonomously compared to an internal focus of attention. The purpose of the current experiment was to investigate if the benefit of an external focus of attention would still exist when participants were asked to change their focus of attention mid-trial. Based on the constrained action hypothesis and the findings of previous research it was hypothesized that participants’ (N= 21) balance on a stabilometer would be superior when using an external focus (i.e., keep the markers level) compared to their balance on a stabilometer when using an internal focus (i.e., keep your feet level). Results did not reveal significant differences in RMSE of the external (M = 6.73, SD = 1.15) and internal (M = 6.09, SD = 1.16) attentional foci. These findings are not with the majority of focus of attention research. Due to these findings it is suggested that practitioners avoid switching their verbal instructions mid-trial. Also future studies should consider using additional dependent variables (i.e. MPF) or conditions where participants do not switch foci mid-trial so a better understanding can be found in regard to the processes that are occurring when participants switch focus of attention mid-trial

Lunar and planetary studies

This grant supports the core program in planetary astronomy at Caltech. The research includes observations in the IR, sub-mm, mm and cm wavelengths at national and Caltech observatories with a strong emphasis on integrating the observations with spacecraft data and with models of atmospheric structure, dynamics and chemistry. Muhleman's group made extensive observations of Saturn, Uranus and Neptune which are being interpreted in terms of deep atmospheric structures which are obvious in the 2 and 6 cm maps of Saturn and Uranus. The microwave measurements are one of the few sources of information below the 2 bar level. Goldreich is investigating the dynamics of narrow rings with postdoctoral fellow, Pierre-Yves Longaretti. Their work has focused on the role of collisional stresses on the precession of the rings, since the Voyager radio science results imply that the previous model based on the ring's self-gravity is not the entire story. In addition Borderies, Goldreich and Tremaine have completed an investigation of the dynamics of the Encke division in Saturn's A ring

Lepidium sativum Effects on Reproduction and Visceral Organ Development in Sprague-Dawley Rats

Plants have been utilized as herbicides, insecticides, antimicrobials, antifungals, antivirals, cosmetics and therapeutic agents. Traditional medicine plays a pivotal role in health care around the globe. Lepidium sativum (LS) has been utilized in cooking for its peppery, tangy flavor and aroma and in traditional medicine. LS has been used to treat inflammation, bone fractures, hypertension, microbial infections, diabetes, bronchial asthma, osteoarthritis, constipation and other diseases. There have been no studies investigating the effects of LS seed extracts on preovulatory surge secretion of gonadotropin releasing hormone (GnRH), luteinizing hormone (LH) and follicle-stimulating hormone (FSH). The highest level of inclusion of LS seeds at 50% has shown lethal effects. At 10% LS seed inclusion has shown ambiguous toxic and non-toxic effects. There is a paucity of information on LS effects on female and male reproductive function. To date, LS has been shown in females to act as a galactagogue, abortifacient and contraceptive. There are ambiguous results of LS having anti-ovulatory properties. In males, LS has been shown to increase testicular and epididymal sperm concentration and act as an aphrodisiac. The objectives of the study were to determine the effect of aqueous LS seed extract on the development and magnitude of surge releases of GnRH, LH and FSH and secondly, to determine the acute and chronic effects of 15% LS seed supplementation on gross organ morphology and histomorphometric indices, testosterone secretion and spermatogenesis in the Sprague-Dawley rat. Thirty-two female Sprague-Dawley rats were ovariectomized using standard procedures for Experiment 1. Ten days post-ovariectomy, all rats were injected with estradiol-17β (10 μg/0.2 mL/rat, s.c. in corn oil) for three days. On the fourth day at 0800 h, sixteen rats were treated with LSE (40 mg/Kg BW, i.p.) while the remaining sixteen received normal saline diluent at the same rate. At 1000 h, eight rats that received LSE and eight rats that received normal saline were treated with corn oil (0.2 mL/rat, s.c.). The remaining sixteen rats were treated with progesterone (2.5 mg/0.2 mL/rat, s.c. in corn oil). At 1300 h, the rats were euthanized using an overdose of 6 mL 2.5% tribromoethanol. The hypothalamus and pituitary glands were extracted and perifused in artificial cerebrospinal fluid for seven hours at a constant temperature of 37°C. Hypothalamic GnRH and pituitary LH and FSH concentrations were determined utilizing radioimmunoassays. There were no significant differences in GnRH, LH or FSH secretions. There was an observed GnRH surge in rats receiving saline and progesterone. Rats that received LSE and progesterone observed an earlier and diminished secretion of GnRH, but was not significant. Progesterone administration had a suppressive effect on LH average secretion. GnRH administration had no effect on LH or FSH secretion. Total hormonal secretions for GnRH, LH and FSH had no significant changes. Forty-eight male Sprague-Dawley rats were utilized for Experiment 2. Upon arrival, rats were given feed and water ad libitum for two weeks for acclimation. The rats were weighed and assigned to either a control group (0% LS seed inclusion; n=24) or a treatment group (15% LS seed inclusion; n=24). At 0800 h rats were offered either normal rat chow or the 15% LS seed included rat chow for 8 weeks. At 2, 4, 6 and 8 weeks, six rats from each the Control or the Treatment groups were euthanized with carbon dioxide asphyxiation for a minimum of 10-minutes. All rats were weighed on the first day of the experiment, every other day and immediately after euthanization. Every day feed intake and refusal was measured. Immediately post euthanization, trunk blood was collected for hormone assays. Further, the paired testicles, epididymides, prostate gland, seminal vesicles, kidneys, adrenal glands, heart, liver, spleen, lungs, brain and pancreas were harvested and weighed. The relative organ weights were normalized to weight per 100 g BW. One kidney and one testis was collected and used for histological analysis. The other testes were utilized for in vitro testosterone production. One cauda epididymis per rat was isolated and used for epididymal sperm count. Our results indicated a decrease in Treatment group’s body weight during the first few days of the experiment. This occurred concurrent with a strong feed aversion for the Treatment group during the first few days. This effect is explained by the novel food source being offered to the rats. There was no effect of LS seed inclusion on adrenal gland, heart, liver, and spleen or lung weight. There was a significant increase in brain weight possibly due to hydrocephalus. There was also a significant increase in pancreatic weight possibly due to pancreatitis. There were no effects of LS supplementation on paired testicular, epididymides or seminal vesicle weights. The prostate gland did show a significant decrease in weight. The mechanism for this significant weight decrease is unknown. The testis histological analysis had no significant results except for an increase in week two Leydig cell diameter. There was no significant changes for in vitro testosterone production or plasma testosterone. Therefore, our results suggest no conclusive data for the aphrodisiac claims. The epididymal sperm density did not have significant changes, although they did increase concurrent between the groups through the experiment. Interestingly, there was an increase in renal weight through the experiment for the Treatment group. Histological analysis showed a significant change in the diameter of the Bowman’s capsule, glomerulus and Bowman’s space for the Treatment group. There was also an increase in glomerulosclerosis, metaplasia and hyperplasia in rats fed 15% LS seed inclusion. In the proximal and distal tubules there was a significant increase in tubular degeneration throughout the experiment. These results paired together show a significant toxic effect for rats fed 15% LS seed. Overall, LS seed consumption for medicinal purposes should be consumed with caution because of the possible narrow therapeutic index

Interpreting the Cosmic Ray Composition

Detailed composition measurements can be a very powerful means of tracing origins, a fact used regularly by forensic scientists and art historians. One of the main motivating factors for making detailed observations of cosmic rays was always the hope that a unique compositional signature could be found which pointed unambiguously to a particular source. This has proven much harder than expected, but we have now reached a point where it appears possible to begin to decipher the information contained in the compositional data; the key, we have discovered, is to read the data not in isolation, but in the context provided by our general astronomical knowledge and by recent developments in shock acceleration theory (Meyer, Drury and Ellison, 1997, 1998; Ellison, Drury and Meyer, 1997). In our view (not, it is only fair to warn the reader, yet universally accepted) the data show clearly that the Galactic cosmic ray particles originate predominantly from the gas and dust of the general interstellar medium.Comment: 14 pages, LaTeX 2.09, 4 figure

SLD Potamology Study (S-9)

Foreword In this report, the authors discuss factors which relate to flow characteristics of the Middle Mississippi River and its major tributaries. The variety of ways in which man and nature interact to affect the hydrologic regime of the study area are almost infinite. Furthermore, the intensity and direction of man\u27s activity is non-uniform with respect to both time and space. Therefore, on the scale of the study area, the authors assert that 1) it is difficult to verify associations between specific human actions and river responses and 2) at this time, it is impossible to do so in a reasonably quantitative manner. These points are not intended to imply support for a course of inaction with regard to management of rivers in the study area. Instead, it is hoped that they will add important new perspective to issues which face those persons charged with the responsibility of protecting the public interest in these vital river resources. Paul R. MungerDirector, Institute of River Studie

Synthesis of GEMS from Shock-accelerated Crystalline Dust in Superbubbles: Model and Predictions

GEMS (Glass Embedded with Metals and Sulfides) are highly enigmatic yet common components of anhydrous IDPs. We have recently proposed a model of GEMS formation from shock-accelerated crystalline dust in superbubbles[1] which explains the three most perplexing properties of GEMS: pseudomorphism[2], their chemistry[3], and their size range. In this Abstract, we briefly review the main points of the model, and suggest tests that will either prove or rule out this hypothesis

The Change of Intensity, Color, Line Strength, and Line Position in the QSS 3C 446 during the 1966 Outburst

During the course of routine observations of quasi-stellar radio sources, 3C 446 was found to be abnormally bright on June 24.4 U.T., 1966 (Sandage 1966). A further observation on July 12.4 U.T., 1966, confirmed this result, showing that the object had undergone an outburst of at least 3.2 mag. sometime between October 5, 1964, and June 24, 1966. This time interval can be narrowed appreciably because a visual estimate of the V magnitude by Schmidt on September 23 and 25, 1965, gave V not brighter than 18 on those dates. The event is of particular importance as it enables us to make several tests concerning the intensity and position of the emission-line features