28,435 research outputs found

    Survivable flight control system fly-by-wire development and flight test

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    Results from an intensive FBW advanced development effort indicate significant improvements in overall flight control system performance, reliability, safety and maintainability. Additionally, the strong and credible FBW technology base developed as a result paved the way for further exploitation through the application of advanced concepts such as control configured vehicles and multi-mode controls

    Determination of gas volume trapped in a closed fluid system

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    Technique involves extracting known volume of fluid and measuring system before and after extraction, volume of entrapped gas is then computed. Formula derived from ideal gas laws is basis of this method. Technique is applicable to thermodynamic cycles and hydraulic systems

    Measuring consumer detriment under conditions of imperfect information

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    Copyright @ 2001 Office of Fair Tradin

    Men Are More Likely than Women to Slow in the Marathon

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    Studies on nonelite distance runners suggest that men are more likely than women to slow their pace in a marathon. Purpose: This study determined the reliability of the sex difference in pacing across many marathons and after adjusting women\u27s performances by 12% to address men\u27s greater maximal oxygen uptake and also incorporating information on racing experience. Methods: Data were acquired from 14 US marathons in 2011 and encompassed 91,929 performances. For 2929 runners, we obtained experience data from a race-aggregating Web site. We operationalized pace maintenance as the percentage change in pace observed in the second half of the marathon relative to the first half. Pace maintenance was analyzed as a continuous variable and as two categorical variables, as follows: maintain the pace, defined as slowing=30%. Results: The mean change in pace was 15.6% and 11.7% for men and women, respectively (P \u3c 0.0001). This sex difference was significant for all 14 marathons. The odds for women were 1.46 (95% confidence interval, 1.41–1.50; P \u3c 0.0001) times higher than men to maintain the pace and 0.36 (95% confidence interval, 0.34–0.38; P \u3c 0.0001) times that of men to exhibit marked slowing. Slower finishing times were associated with greater slowing, especially in men (interaction, P \u3c 0.0001). However, the sex difference in pacing occurred across age and finishing time groups. Making the 12% adjustment to women’s performances lessened the magnitude of the sex difference in pacing but not its occurrence. Although greater experience was associated with less slowing, controlling for the experience variables did not eliminate the sex difference in pacing. Conclusions: The sex difference in pacing is robust. It may reflect sex differences in physiology, decision making, or both

    New light on the ‘Drummer of Tedworth’: conflicting narratives of witchcraft in Restoration England

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    This paper presents a definitive text of hitherto little-known early documents concerning ‘The Drummer of Tedworth’, a poltergeist case that occurred in 1662-3 and became famous not least due to its promotion by Joseph Glanvill in his demonological work, Saducismus Triumphatus. On the basis of these and other sources, it is shown how responses to the events at Tedworth evolved from anxious piety on the part of their victim, John Mompesson, to confident apologetic by Glanvill, before they were further affected by the emergence of articulate scepticism about the case

    Liquid friction on charged surfaces: from hydrodynamic slippage to electrokinetics

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    Hydrodynamic behavior at the vicinity of a confining wall is closely related to the friction properties of the liquid/solid interface. Here we consider, using Molecular Dynamics simulations, the electric contribution to friction for charged surfaces, and the induced modification of the hydrodynamic boundary condition at the confining boundary. The consequences of liquid slippage for electrokinetic phenomena, through the coupling between hydrodynamics and electrostatics within the electric double layer, are explored. Strong amplification of electro-osmotic effects is revealed, and the non-trivial effect of surface charge is discussed. This work allows to reconsider existing experimental data, concerning Zeta potentials of hydrophobic surfaces and suggest the possibility to generate ``giant'' electro-osmotic and electrophoretic effects, with direct applications in microfluidics

    Self reported aggravating activities do not demonstrate a consistent directional pattern in chronic non specific low back pain patients: An observational study

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    Question: Do the self-reported aggravating activities of chronic non-specific low back pain patients demonstrate a consistent directional pattern? Design: Cross-sectional observational study. Participants: 240 chronic non specific low back pain patients. Outcome measure: We invited experienced clinicians to classify each of the three self-nominated aggravating activities from the Patient Specific Functional Scale by the direction of lumbar spine movement. Patients were described as demonstrating a directional pattern if all nominated activities moved the spine into the same direction. Analyses were undertaken to determine if the proportion of patients demonstrating a directional pattern was greater than would be expected by chance. Results: In some patients, all tasks did move the spine into the same direction, but this proportion did not differ from chance (p = 0.328). There were no clinical or demographic differences between those who displayed a directional pattern and those who did not (all p > 0.05). Conclusion: Using patient self-reported aggravating activities we were unable to demonstrate the existence of a consistent pattern of adverse movement in patients with chronic non-specific low back pain

    Large Magnetic Fields and Motions of OH Masers in W75 N

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    We report on a second epoch of VLBA observations of the 1665 and 1667 MHz OH masers in the massive star-forming region W75 N. We find evidence to confirm the existence of very strong (~40 mG) magnetic fields near source VLA 2. The masers near VLA 2 are dynamically distinct and include a very bright spot apparently moving at 50 km/s relative to those around VLA 1. This fast-moving spot may be an example of a rare class of OH masers seen in outflows in star-forming regions. Due to the variability of these masers and the rapidity of their motions, tracking these motions will require multiple observations over a significantly shorter time baseline than obtained here. Proper motions of the masers near VLA 1 are more suggestive of streaming along magnetized shocks rather than Keplerian rotation in a disk. The motions of the easternmost cluster of masers in W75 N (B) may be tracing slow expansion around an unseen exciting source.Comment: 7 pages including 4 figures (2 color) & 3 tables, to appear in Ap

    MPEG-7 Harmonization with Dublin Core: Current Status and Concerns

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    This document presents the current status of the harmonization of MPEG-7 with Dublin Core. It provides mappings between both qualified and unqualified Dublin Core and MPEG-7 Descriptors (Ds) (in the context of their container Description Schemes (DSs)). This mapping also highlights a certain number of problems and concerns with the current MPEG-7 Multimedia DSs and Ds. Section 2 provides a brief overview of the Dublin Core Metadata Initiative. Section 3 provides a mapping between unqualified Dublin Core and MPEG-7 Ds and DSs. Section 4 provides a mapping between qualified Dublin Core (as recommended by the DC Usage Committee) and MPEG-7 Ds and DSs. Section 5 lists the concerns and issues with the MDS which have been raised as a result of performing these mappings

    Optic nerve head segmentation

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    Reliable and efficient optic disk localization and segmentation are important tasks in automated retinal screening. General-purpose edge detection algorithms often fail to segment the optic disk due to fuzzy boundaries, inconsistent image contrast or missing edge features. This paper presents an algorithm for the localization and segmentation of the optic nerve head boundary in low-resolution images (about 20 /spl mu//pixel). Optic disk localization is achieved using specialized template matching, and segmentation by a deformable contour model. The latter uses a global elliptical model and a local deformable model with variable edge-strength dependent stiffness. The algorithm is evaluated against a randomly selected database of 100 images from a diabetic screening programme. Ten images were classified as unusable; the others were of variable quality. The localization algorithm succeeded on all bar one usable image; the contour estimation algorithm was qualitatively assessed by an ophthalmologist as having Excellent-Fair performance in 83% of cases, and performs well even on blurred image
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