2,311 research outputs found

    A computer program to calculate radiating viscous stagnation streamline flow with strong blowing

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    A computer program (program LEE) has been developed to calculate the fully coupled solution of the radiating viscous stagnation streamline flow with strong blowing. The report describes the digital computer program, including FORTRAN IV listing, flow charts, instructions for the user, and a test case with input and output. Program LEE is available through COSMIC

    American Option Pricing: A Simulated Approach

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    This study examines methods of pricing American style options, moving from the binomial model to the Black Scholes method and finishing with simulated method of option pricing. A simulated approached is based off the work established by Longstaff and Schwartz (2001) and extended by Rambharat and Brockwell (2010). Downfalls of these methods are discussed, as are ways to improve upon them. Using Monte Carlo methods and particle filtering will lead to a platform where options are priced with greater detail. Also, these simulated methods lead to faster computing time allowing for a more efficient use of resources and a theoretical framework of pricing

    An implicit finite-difference solution to the viscous shock layer, including the effects of radiation and strong blowing

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    An implicit finite-difference scheme is developed for the fully coupled solution of the viscous, radiating stagnation-streamline equations, including strong blowing. Solutions are presented for both air injection and injection of carbon-phenolic ablation products into air at conditions near the peak radiative heating point in an earth entry trajectory from interplanetary return missions. A detailed radiative-transport code that accounts for the important radiative exchange processes for gaseous mixtures in local thermodynamic and chemical equilibrium is utilized in the study. With minimum number of assumptions for the initially unknown parameters and profile distributions, convergent solutions to the full stagnation-line equations are rapidly obtained by a method of successive approximations. Damping of selected profiles is required to aid convergence of the solutions for massive blowing. It is shown that certain finite-difference approximations to the governing differential equations stabilize and improve the solutions. Detailed comparisons are made with the numerical results of previous investigations. Results of the present study indicate lower radiative heat fluxes at the wall for carbonphenolic ablation than previously predicted

    Characteristics of Marshallese with Type 2 Diabetes on Oahu: A Pilot Study to Implement a Community-based Diabetic Health Improvement Project

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    Objectives – To determine the feasibility of a resident physician-based, culturally appropriate method of decreasing the disease burden of Type 2 Diabetes Mellitus (DM2) in a group of Pacific Islanders, Marshallese living in Hawai'i. Methods – Thirty Marshallese with diabetes who live on the island of Oahu, Hawaii were recruited. Baseline health status of the participants was characterized. Health parameters included HgbA1c, random blood sugar (RBS), lipid panels, body mass index (BMI), blood pressure, and medical history, along with qualitative information. A focus group was held with participants prior to beginning the curriculum to determine cultural views on diabetes, health, treatment, and to identify potential obstacles to health improvement. A DM2 educational curriculum culturally relevant to Marshallese populations was then started, including instruction in lifestyle modification, adherence to medication regimens, and planned quarterly assessment of health improvement. Results – Baseline quantitative analysis revealed Marshallese with diabetes to be obese and hyperglycemic, with average BMI of 30 kg/m2 , RBS of 285, and HgbA1c of 9.3. Qualitative analysis revealed that nearly half the participants admitted to symptoms of severe hyperglycemia. The initial focus group had a substantial turnout. Attendance rapidly declined, becoming so low that classes were eventually terminated. However, in two participants who attended more than three classes there was evidence of major improvements in HgbA1c, cholesterol, and qualitative markers, which were sustained after one year. Conclusions – This pilot study of Marshallese with diabetes on Oahu showed that the majority had poor glycemic control with secondary co-morbid conditions. Although many barriers exist for successful implementation of a diabetes health improvement project in this group, the groundwork for translation of this project to the Republic of Marshall Islands (RMI) has been laid; curriculum translation and patient recruitment is currently underway to advance the project

    Voting in the bicameral Congress: large majorities as a signal of quality

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    publication-status: Acceptedtypes: ArticleWe estimate a model of voting in Congress that allows for dispersed information about the quality of proposals in an equilibrium context. In equilibrium, the Senate only approves House bills that receive the support of a supermajority of members of the lower chamber. We estimate this endogenous supermajority rule to be about four-fifths on average across policy areas. Our results indicate that the value of information dispersed among legislators is significant, and that in equilibrium a large fraction of House members' (40–50%) votes following their private information. Finally, we show that the probability of a type I error in Congress (not passing a good bill) is on average about twice as high as the probability of a type II error (passing a low-quality bill)

    ACAS-Xu Run 5 HITL (June 2019) SC-228 WG 1.3 Results Outbrief

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    This presentation provides an overview of a recently completed human-in-the-loop simulation, conducted as part of the Unmanned Aircraft Systems (UAS) Integration in the National Airspace System (NAS) Project. This study examined how to present resolution advisories (RAs) issued by Airborne Collision Avoidance System (ACAS) Xu, which can be in the vertical dimension, the horizontal dimension, or both (i.e., blended). The study varied the location of the ACAS Xu traffic information - it was either presented within an 'integrated' display or a 'standalone' display, where the traffic information was separated from the vehicle control interfaces and navigational information. Results revealed generally positive feedback on the visual and aural presentation of RAs, with special considerations and performance implications noted throughout

    1-(1-Carboxy­methyl-1,4-anhydro-2,3-O-isopropyl­idene-α-d-erythrofuranos­yl)thymine

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    X-Ray crystallography unequivocally determined the stereochemistry of the thymine base in the title compound, C14H18N2O7. The absolute stereochemistry was determined from the use of d-ribose as the starting material. There are two independent mol­ecules in the asymmetric unit (Z′ = 2) which exist as N—H⋯O hydrogen-bonded pairs in the crystal structure

    AGN and starbursts at high redshift: High resolution EVN radio observations of the Hubble Deep Field

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    We present deep, wide-field European VLBI Network (EVN) 1.6 GHz observations of the Hubble Deep Field (HDF) region with a resolution of 0.025 arcseconds. Above the 210 microJy/beam (5sigma) detection level, the EVN clearly detects two radio sources in a field that encompasses the HDF and part of the Hubble Flanking Fields (HFF). The sources detected are: VLA J123644+621133 (a z=1.013, low-luminosity FR-I radio source located within the HDF itself) and VLA J123642+621331 (a dust enshrouded, optically faint, z=4.424 starburst system). A third radio source, J123646+621404, is detected at the 4sigma level. The VLBI detections of all three sources suggest that most of the radio emission of these particular sources (including the dusty starburst) is generated by an embedded AGN.Comment: 4 pages, 1 figure; Accepted by Astron. & Astrophys Letters ... See http://www.nfra.nl/~mag/hdf_evn.htm
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