Small-scale self-focusing effects in a high power glass laser amplifier

Experimental data and the results of detailed numerical calculations are presented for small scale beam breakup due to non-linear self-focusing in Cyclops, a high power Nd-glass laser amplifier. Both perturbed plane wave and nonlinear whole beam calculations were carried out. The whole beam calculations were carried out using a dust particle model of beam perturbations.     

Geotherm: the U.S. geological survey geothermal information system

GEOTHERM is a comprehensive system of public databases and software used to store, locate, and evaluate information on the geology, geochemistry, and hydrology of geothermal systems. Three main databases address the general characteristics of geothermal wells and fields, and the chemical properties of geothermal fluids; the last database is currently the most active. System tasks are divided into four areas: (1) data acquisition and entry, involving data entry via word processors and magnetic tape; (2) quality assurance, including the criteria and standards handbook and front-end data-screening programs; (3) operation, involving database backups and information extraction; and (4) user assistance, preparation of such items as application programs, and a quarterly newsletter. The principal task of GEOTHERM is to provide information and research support for the conduct of national geothermal-resource assessments. The principal users of GEOTHERM are those involved with the Geothermal Research Program of the U.S. Geological Survey. Information in the system is available to the public on request.     

The influence of situation and coping on relapse crisis outcomes after smoking cessation.

Examines the influence of situational characteristics and coping on the outcome of a relapse crisis for 232 Ss followed for 1 month after a self-initiated smoking cessation attempt. Survival of a relapse crisis was most strongly related to the number of coping strategies used. All coping strategies were equally effective; furthermore, combining cognitive and behavioral coping strategies was not more effective than using multiple cognitive or multiple behavioral strategies. During the second half of the follow-up period (Weeks 3 and 4 postcessation), the presence of smokers resulted in a decreased likelihood of coping and an increased likelihood of smoking. In addition, active coping was marginally related to higher baseline levels of motivation to quit. When motivation and the presence of smokers were controlled, however, coping still significantly predicted outcome. Results are discussed with reference to previous relapse studies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of sequential preoptic and mammillary lesions on male rat sexual behavior.

Observed the sexual behavior of 52 male Sprague-Dawley rats prior to and following bilateral medial preoptic, unilateral medial preoptic, bilateral posterior preoptic, bilateral mammillary, and sham lesions. Bilateral medial preoptic lesions and mammillary lesions were made either simultaneously or sequentially within the same Ss in separate groups. Mammillary lesions had no effect on sexual behavior. Complete destruction of the medial preoptic area made prior to, simultaneous with, and following mammillary lesions completely abolished mating behavior. Partial destruction of the medial preoptic area increased mount and intromission latencies and slightly increased ejaculation latency. Results suggest that since there was no change in the postejaculatory-refractory interval, the medial preoptic area mediates sexual arousal but apparently is not involved in a copulatory-ejaculatory mechanism. (32 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effect of sonification display pulse rate and reliability on operator trust and perceived workload during a simulated patient monitoring task

The present study investigated the effects of sonification pulse rate and sensor reliability on operator trust and mental workload. Processing resources and operator trust were sensitive to both pulse rate and sensor reliability. These findings suggest that setting pulse rates to 60 pulses per min may have considerable benefits in critical task environments.     

The efficacy of a medical virtual reality simulator for training phlebotomy

OBJECTIVE: The present study compared the effectiveness of a virtual reality (VR) simulator for training phlebotomy with that of a more traditional approach using simulated limbs. BACKGROUND: Phlebotomy, or drawing blood, is one of the most common medical procedures; yet, there are no universal standards for training and assessing performance. The absence of any standards can lead to injuries and inaccurate test results if the procedure is improperly performed. METHOD: Twenty 3rd-year medical students were trained under one of the two methods and had their performance assessed with a 28-item checklist. RESULTS: The results showed that performance improvements were limited to those who trained with the simulated limbs, and a detailed comparison of the two systems revealed several functional and physical differences that may explain these findings. CONCLUSION: Participants trained with simulated limbs performed better than those trained with a VR simulator; however, the metrics recorded by the VR system may address some aspects of performance that could eventually prove beneficial. APPLICATION: The present study highlights the potential for medical simulators to improve patient safety by enabling trainees to practice procedures on devices instead of patients. Applications of this research include training, performance assessment, and design of simulator systems.     

The triglyceride composition,structure, and presence of estolides in the oils ofLesquerella and related species

Members of the genusLesquerella, native to North America, have oils containing large amounts of hydroxy fatty acids and are under investigation as potential new crops. The triglyceride structure of oils from twenty-fiveLesquerella species in the seed collection at our research center has been examined after being hydrolysis-catalyzed by reverse micellar-encapsulated lipase and alcoholysis-catalyzed by immobilized lipase. These reactions, when coupled with supercritical-fluid chromatographic analysis, provide a powerful, labor-saving method for oil triglyceride analysis. A comprehensive analysis of overall fatty acid composition of these oils has been conducted as well.Lesquerella oils (along with oils from two other Brassicaceae:Physaria floribunda andHeliophilia amplexicaulis) have been grouped into five categories: densipolic acid-rich (Class I); auricolic acid-rich (Class II); lesquerolic acid-rich (Class III); an oil containing a mixture of hydroxy acids (Class IV); and lesquerolic and erucic acid-rich (Class V). The majority of Class I and II triglycerides contain one or two monoestolides at the 1- and 3-glycerol positions and a C₁₈ polyunsaturated acyl group at the 2-position. Most Class III and IV oil triglycerides contain one or two hydroxy acids at the 1- and 3-positions and C₁₈ unsaturated acid at the 2-position. A few of the Class III oils have trace amounts of estolides. The Class V oil triglycerides are mostly pentaacyl triglycerides and contain monestolide and small amounts of diestolide. Our triglyceride structure assignments were supported by¹H nuclear magnetic resonance data and mass balances.     

Cathodoluminescence Study of Orientation-Patterned GaAs Crystals for Nonlinear Optics

Orientation-patterned (OP) GaAs crystals are very promising for their use in nonlinear optical applications. In particular, mid-infrared and terahertz lasers can be generated by frequency conversion from shorter-wavelength sources. However, the quality of the crystals is crucial for high conversion efficiency, as the presence of defects with electrooptical signatures can contribute to optical losses. The study of these defects is a step toward the improvement of OP-GaAs crystals. We present here a spectroscopic cathodoluminescence study of the distribution of the main defects. Tentative relations between defects and the optical propagation losses are discussed.