40,730 research outputs found

    Ground effects on Loran-C signals

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    In conjunction with the test and evaluation of the position fixing capabilities of the Army Manpack Loran Receiver AN/PSN-6, an extensive series of time difference and signal amplitude measurements were made within a 100 km map grid square encompassing Fort Monmouth, New Jersey. The test location is within the coverage area of the East Coast Loran-C Chain. The data were used to develop a simple smooth-earth model for the test area as well as to estimate the magnitude and distributions of deviations from this model. Local propagation processes associated with topographic features and the grid of overhead wires in the test area are shown to contribute to the deviations from the model

    Investigation of the free flow electrophoretic process

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    The effects of gravity on the free flow electrophoretic process was demonstrated. The free flow electrophoresis chamber used to demonstrate the effects of gravity on the process was of a proprietary design. This chamber was 120 cm long, 16 cm wide, and 0.15 cm thick. Flow in this chamber was in the upward direction and exited through 197 outlets at the top of the chamber. During electrophoresis a stream of sample was injected into the flow near the bottom of the chamber and an electrical field was applied across the width of the chamber. The field caused a lateral force on particles in the sample proportional to the inherent change of the particle and the electric field strength. Particle lateral velocity was then dependent on the force due to viscous drag which was proportional to particle size and particle shape dependent

    Investigation of the free flow electrophoretic process. Volume 1: Executive summary

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    The effect of gravity on the free flow electrophoretic process was investigated. The demonstrated effects were then compared with predictions made by mathematical models. Results show that the carrier buffer flow was affected by gravity induced thermal convection and that the movement of the separating particle streams was affected by gravity induced buoyant forces. It was determined that if gravity induced buoyant forces were included in the mathematical models, then effective predictions of electrophoresis chamber separation performance were possible

    Effect of folic acid supplementation in pregnancy on preeclampsia: The folic acid clinical trial study

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    Copyright © 2013 Shi Wu Wen et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Preeclampsia (PE) is hypertension with proteinuria that develops during pregnancy and affects at least 5% of pregnancies. The Effect of Folic Acid Supplementation in Pregnancy on Preeclampsia: the Folic Acid Clinical Trial (FACT) aims to recruit 3,656 high risk women to evaluate a new prevention strategy for PE: supplementation of folic acid throughout pregnancy. Pregnant women with increased risk of developing PE presenting to a trial participating center between 80/7 and 166/7 weeks of gestation are randomized in a 1: 1 ratio to folic acid 4.0 mg or placebo after written consent is obtained. Intent-to-treat population will be analyzed. The FACT study was funded by the Canadian Institutes of Health Research in 2009, and regulatory approval from Health Canada was obtained in 2010. A web-based randomization system and electronic data collection system provide the platform for participating centers to randomize their eligible participants and enter data in real time. To date we have twenty participating Canadian centers, of which eighteen are actively recruiting, and seven participating Australian centers, of which two are actively recruiting. Recruitment in Argentina, UK, Netherlands, Brazil, West Indies, and United States is expected to begin by the second or third quarter of 2013. This trial is registered with NCT01355159. © 2013 Shi Wu Wen et al.The Canadian Institutes of Healt

    Study of process technology for GaAlAs/GaAs heteroface solar cells

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    Two processes were considered: the infinite melt process and the finite melt process. The only technique that is developed to the point that 10,000 cells could be produced in one year is the infinite melt liquid phase epitaxy process. The lowest cost per cell was achieved with the advanced metal organic chemical vapor deposition process. Molecular beam epitaxy was limited by the slow growth rate. The lowest cost, an 18 percent efficient cell at air mass zero, was approximately $70 per watt

    K2 Variable Catalogue: Variable Stars and Eclipsing Binaries in K2 Campaigns 1 and 0

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    We have created a catalogue of variable stars found from a search of the publicly available K2 mission data from Campaigns 1 and 0. This catalogue provides the identifiers of 8395 variable stars, including 199 candidate eclipsing binaries with periods up to 60d and 3871 periodic or quasi-periodic objects, with periods up to 20d for Campaign 1 and 15d for Campaign 0. Lightcurves are extracted and detrended from the available data. These are searched using a combination of algorithmic and human classification, leading to a classifier for each object as an eclipsing binary, sinusoidal periodic, quasi periodic, or aperiodic variable. The source of the variability is not identified, but could arise in the non-eclipsing binary cases from pulsation or stellar activity. Each object is cross-matched against variable star related guest observer proposals to the K2 mission, which specifies the variable type in some cases. The detrended lightcurves are also compared to lightcurves currently publicly available. The resulting catalogue is made available online via the MAST archive at https://archive.stsci.edu/prepds/k2varcat/, and gives the ID, type, period, semi-amplitude and range of the variation seen. We also make available the detrended lightcurves for each object.Comment: Accepted by A&A. 6 pages, 6 figures. Catalogue and lightcurves are available online via MAST at https://archive.stsci.edu/prepds/k2varcat

    Narrative coherence in multiple forensic interviews with child witnesses alleging physical and sexual abuse

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    This study investigated the narrative coherence of children's accounts elicited in multiple forensic interviews. Transcriptions of 56 police interviews with 28 children aged 3–14 years alleging physical and sexual abuse were coded for markers of completeness, consistency and connectedness. We found that multiple interviews increased the completeness of children's testimony, containing on average almost twice as much new information as single interviews, including crucial location, time and abuse‐related details. When both contradictions within the same interview and across interviews were considered, contradictions were not more frequent in multiple interviews. The frequency of linguistic markers of connectedness remained stable across interviews. Multiple interviews increase the narrative coherence of children's testimony through increasing their completeness without necessarily introducing contradictions or decreasing causal‐temporal connections between details. However, as ‘ground truth’ is not known in field studies, further investigation of the relationship between the narrative coherence and accuracy of testimonies is required
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