Wide Angle Achromatic Prism Beam Steering for Infrared Countermeasures Applications

The design and analysis of achromatic doublet prisms for use in laser beam steering is presented. The geometric relationships describing the maximum steering angle are given, as are discussions of first- and second-order dispersion reduction. Infrared (IR) material alternatives and optimum IR material characteristics for wide-angle achromatic prism beam steering are also investigated. Sixteen materials in 120 different combinations have been examined to date. For midwave IR applications it is shown that the minimum dispersion currently achievable across the full 2 to 5 μm spectrum is 1.7816 mrad at an average maximum steering angle of 45 deg. This is accomplished using LiF/ZnS doublet prisms. Several issues related to the azimuth and elevation angles into which light is steered as a function of prism rotation angles are also presented

Modeling the Balance between Standardization and Innovation in a Flight School

The purpose of this paper is to examine the relationship between standardization and innovation in a university flight training program. Quantitative and qualitative data were generated for this investigation by a human subjects study involving senior students in a collegiate pro-pilot program. The survey provided the following lack of innovation indicators: (a) failure to achieve program goals; (b) loss of flight training students to competitor flight schools; and (c) substandard flight training efficiency. A model describing the balance between standardization and innovation is proposed: (a) too much standardization mires a flight school in stagnation; (b) too little standardization results in a lack of professionalism; (c) too much innovation creates a chaotic training program; (d) too little innovation produces unmotivated students; and (e) too many resistors to change at the management level results in stagnation and a lack of innovation. Flight schools that can achieve a good balance between standardization and innovation would enjoy two main benefits: (a) positive and imaginative learning atmosphere that encourages instructors to train their students above and beyond the minimum standards without sacrificing safety; and (b) exciting and creative training environment that motivates students to achieve their goals without sacrificing professionalism

Inflation, Forecast Intervals and Long Memory Regression Models

We examine recursive out-of-sample forecasting of monthly postwar U.S. core inflation and log price levels. We use the autoregressive fractionally integrated moving average model with explanatory variables (ARFIMAX). Our analysis suggests a significant explanatory power of leading indicators associated with macroeconomic activity and monetary conditions for forecasting horizons up to two years. Even after correcting for the effect of explanatory variables, there is conclusive evidence of both fractional integration and structural breaks in the mean and variance of inflation in the 1970s and 1980s and we incorporate these breaks in the forecasting model for the 1980s and 1990s. We compare the results of the fractionally integrated ARFIMA(0,d,0) model with those for ARIMA(1,d,1) models with fixed order of d=0 and d=1 for inflation. Comparing mean squared forecast errors, we find that the ARMA(1,1) model performs worse than the other models over our evaluation period 1984-1999. The ARIMA(1,1,1) model provides the best forecasts, but its multi-step forecast intervals are too large

Process for a Reactive Monomer Alignment Layer for Liquid Crystals Formed on an Azodye Sublayer

In this work, the detailed studies of surface polymerization stabilizing liquid crystal formed on an azodye sublayer are presented. The surface localized stabilization is obtained by free-radical polymerization of a dilute solution of a bi-functional reactive monomer (RM) in a liquid crystal (LC) solvent. To optimize the process for surface localized stabilization, we investigate the effects of several process parameters including RM concentration in LC hosts, the types of materials (either RM or LC), the photo-initiator (PI) concentration, ultra-violet (UV) polymerization intensity, and the UV curing temperature. The quality of surface localized stabilization is characterized and/or evaluated by optical microscopy, electro-optical behavior (transmission/voltage curve), the life test, and photo-bleaching. Our results show that, by carefully selecting materials, formulating mixtures, and controlling the polymerizing variables, the RM polymerization can be realized either at the surface or through the bulk. Overall, the combination of surface localized stabilization and photo-alignment offers an elegant and dynamic solution for controlling the alignment for LC, which could play a profound role in almost all liquid crystal optical devices. Keywords: photoalignment; liquid crystals; reactive monomers; azo dyeUnited States. Army Research Office (Contract W911NF-14-1-0650

Comparing endovenous laser ablation, foam sclerotherapy, and conventional surgery for great saphenous varicose veins

BackgroundMany case series have been published on treatments of varicose veins, but comparative randomized controlled trials remain sparse.ObjectiveTo compare the anatomic success rate, frequency of major complications, and quality-of-life improvement of endovenous laser ablation (EVLA), ultrasound-guided foam sclerotherapy (UGFS), and conventional surgery (CS), after 1-year follow-up.MethodsA total of 240 consecutive patients with primary symptomatic great saphenous vein reflux were randomized to EVLA, UGFS, or CS, consisting of high ligation and short stripping. Primary outcome was anatomic success defined as obliteration or absence of the treated vein on ultrasound examination after 1 year. Secondary outcomes were complications, improvement of the “C” class of the CEAP classification, and improvement of disease-specific (Chronic Venous Insufficiency Quality-of-Life Questionnaire) and general (EuroQol 5) quality-of-life scores.ResultsMore than 80% of the study population was classified as C2 or C3 venous disease. After 1 year, the anatomic success rate was highest after EVLA (88.5%), followed by CS (88.2%) and UGFS (72.2%) (P < .001). The complication rate was low and comparable between treatment groups. All groups showed significant (P < .001) improvement of EuroQol 5 and Chronic Venous Insufficiency Quality-of-Life Questionnaire scores after therapy; 84.3% of all treated patients showed an improvement of the “C” of the CEAP classification.ConclusionsAfter 1-year follow-up, EVLA is as effective as CS and superior to UGFS according to occlusion on ultrasound duplex. Quality of life improves after treatment in all groups significantly

P112 Influence of Cuff Blood Pressure Accuracy on Identification of Isolated Systolic Hypertension

Abstract Introduction Isolated systolic hypertension (ISH) is the most common form of hypertension in older people. However, accurate identification of ISH may be hindered because cuff blood pressure (BP) underestimates systolic BP (SBP) and overestimates diastolic BP (DBP). This study aimed to determine the influence of cuff BP accuracy on the identification of ISH. Methods Cuff BP and invasive aortic BP were measured simultaneous (or near-simultaneously) in 1737 subjects (63 ± 12 years, 68% male) during coronary angiography. Data was derived from 32 studies, using 20 different cuff BP devices, from the Invasive Blood Pressure Consortium (INSPECT). ISH was defined as ≥140/<90 mmHg according to cuff BP and invasive aortic BP. Results According to cuff BP, 25% of subjects (n = 430) had ISH, however, 37% (n = 648) were identified with ISH from invasive aortic BP. There was 77% concordance between cuff and invasive BP for identifying ISH. Among the 23% (n = 408) of subjects misclassified by cuff BP, 38% (n = 155) of misclassification was from SBP underestimation (mean: −16.6, 95% CI: −18.9 to −13.9 mmHg), whereas 35% (n = 143) was from DBP overestimation (15.6, 11.9 to 19.0 mmHg) and 20% (n = 83) from SBP overestimation (17.6, 14.4 to 20.5 mmHg). Subjects misclassified were on average 2.7 years older and had greater body mass index (0.8 kg/m2) than those correctly classified. Conclusion Approximately one quarter of older subjects have ISH misclassified, mostly because of underestimation of cuff SBP and overestimation of cuff DBP. This demonstrates a need to improve the accuracy of cuff BP methods for greater precision in identifying ISH