16,383 research outputs found

    Data acquisition system for NASA LaRC impact dynamics research facility

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    A data system is designed to permit the simultaneous recording of 90 data channels on one 28 track magnetic tape recorder using a constant bandwidth FM multiplexing technique. Dynamic signals from transducers located in the test aircraft are amplified and fed to voltage controlled oscillators where they are converted to discrete FM signals. The signals from each group of five VCO's are fed to a mixer/distribution amplifier where they are combined into one composite signal and recorded, using direct recording techniques, on one magnetic tape recorder track. Millivolt signals from the recorders reproduce heads are amplified to one volt and then electronically switched to an FM demultiplexing system where appropriate frequency discrimination and signal filtering recover the original analog information

    Coupling and higher-order effects in the 12C(d,p)13C and 13C(p,d)12C reactions

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    Coupled channels calculations are performed for the 12C(d,p)13C and 13C(p,d)12C reactions between 7 and 60 MeV to study the effect of inelastic couplings in transfer reactions. The effect of treating transfer beyond Born approximation is also addressed. The coupling to the 12C 2+ state is found to change the peak cross-section by up to 15 %. Effects beyond Born approximation lead to a significant renormalization of the cross-sections, between 5 and 10 % for deuteron energies above 10 MeV, and larger than 10 % for lower energies. We also performed calculations including the remnant term in the transfer operator, which has a small impact on the 12C(d,p)13C(g.s.) and 13C(p,d)12C(g.s.) reactions. Above 30 MeV deuteron energy, the effect of the remnant term is larger than 10 % for the 12C(d,p)13C(3.09 MeV) reaction and is found to increase with decreasing neutron separation energy for the 3.09 MeV state of 13C. This is of importance for transfer reactions with weakly bound nuclei.Comment: 7 pages, 7 figures, submitted to Phys. Rev.

    Learning Rich Geographical Representations: Predicting Colorectal Cancer Survival in the State of Iowa

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    Neural networks are capable of learning rich, nonlinear feature representations shown to be beneficial in many predictive tasks. In this work, we use these models to explore the use of geographical features in predicting colorectal cancer survival curves for patients in the state of Iowa, spanning the years 1989 to 2012. Specifically, we compare model performance using a newly defined metric -- area between the curves (ABC) -- to assess (a) whether survival curves can be reasonably predicted for colorectal cancer patients in the state of Iowa, (b) whether geographical features improve predictive performance, and (c) whether a simple binary representation or richer, spectral clustering-based representation perform better. Our findings suggest that survival curves can be reasonably estimated on average, with predictive performance deviating at the five-year survival mark. We also find that geographical features improve predictive performance, and that the best performance is obtained using richer, spectral analysis-elicited features.Comment: 8 page

    Mid-Infrared Ethane Emission on Neptune and Uranus

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    We report 8- to 13-micron spectral observations of Neptune and Uranus from the NASA Infrared Telescope Facility spanning more than a decade. The spectroscopic data indicate a steady increase in Neptune's mean atmospheric 12-micron ethane emission from 1985 to 2003, followed by a slight decrease in 2004. The simplest explanation for the intensity variation is an increase in stratospheric effective temperature from 155 +/- 3 K in 1985 to 176 +/- 3 K in 2003 (an average rate of 1.2 K/year), and subsequent decrease to 165 +/- 3 K in 2004. We also detected variation of the overall spectral structure of the ethane band, specifically an apparent absorption structure in the central portion of the band; this structure arises from coarse spectral sampling coupled with a non-uniform response function within the detector elements. We also report a probable direct detection of ethane emission on Uranus. The deduced peak mole fraction is approximately an order of magnitude higher than previous upper limits for Uranus. The model fit suggests an effective temperature of 114 +/- 3 K for the globally-averaged stratosphere of Uranus, which is consistent with recent measurements indicative of seasonal variation.Comment: Accepted for publication in ApJ. 16 pages, 10 figures, 2 table

    Use of methergine for the prevention of postoperative endometritis in non-elective cesarean section patients.

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    OBJECTIVE: Methergine increases constriction of uterine musculature which may facilitate sloughing of endometrial debris, close uterine vessels, and prevent post-cesarean endometritis. The objective of this study was to evaluate the efficacy of methergine in preventing endometritis in patients undergoing non-elective cesarean section delivery. METHODS: Eighty patients undergoing non-elective cesarean section were enrolled in a prospective randomized clinical trial of methergine (41) versus no methergine (39) administration during the postpartum period. The hospital records were abstracted after discharge to compare the postpartum course. RESULTS: There were no significant demographic differences between the two groups. The women receiving methergine had a significant reduction in the rate of postoperative endometritis (10% vs. 36%, P < 0.005). In addition, the mean postoperative hemoglobin was significantly higher in the methergine treated group (P < 0.001). CONCLUSIONS: The use of methergine postpartum in women undergoing non-elective cesarean sections significantly reduces the incidence of postoperative endometritis and blood loss

    Exposure to atmospheric radon.

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    We measured radon (222Rn) concentrations in Iowa and Minnesota and found that unusually high annual average radon concentrations occur outdoors in portions of central North America. In some areas, outdoor concentrations exceed the national average indoor radon concentration. The general spatial patterns of outdoor radon and indoor radon are similar to the spatial distribution of radon progeny in the soil. Outdoor radon exposure in this region can be a substantial fraction of an individual's total radon exposure and is highly variable across the population. Estimated lifetime effective dose equivalents for the women participants in a radon-related lung cancer study varied by a factor of two at the median dose, 8 mSv, and ranged up to 60 mSv (6 rem). Failure to include these doses can reduce the statistical power of epidemiologic studies that examine the lung cancer risk associated with residential radon exposure
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