1,318 research outputs found

    A Technique to Derive Improved Proper Motions for Kepler Objects of Interest

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    We outline an approach yielding proper motions with higher precision than exists in present catalogs for a sample of stars in the Kepler field. To increase proper motion precision we combine first moment centroids of Kepler pixel data from a single Season with existing catalog positions and proper motions. We use this astrometry to produce improved reduced proper motion diagrams, analogous to a Hertzsprung-Russell diagram, for stars identified as Kepler Objects of Interest. The more precise the relative proper motions, the better the discrimination between stellar luminosity classes. With UCAC4 and PPMXL epoch 2000 positions (and proper motions from those catalogs as quasi-bayesian priors) astrometry for a single test Channel (21) and Season (0) spanning two years yields proper motions with an average per-coordinate proper motion error of 1.0 millisecond of arc per year, over a factor of three better than existing catalogs. We apply a mapping between a reduced proper motion diagram and an HR diagram, both constructed using HST parallaxes and proper motions, to estimate Kepler Object of Interest K-band absolute magnitudes. The techniques discussed apply to any future small-field astrometry as well as the rest of the Kepler field.Comment: Accepted to The Astronomical Journal 15 August 201

    Sensing and control in dual-recycling laser interferometer gravitational-wave detectors

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    We introduce length-sensing and control schemes for the dual-recycled cavity-enhanced Michelson interferometer configuration proposed for the Advanced Laser Interferometer Gravitational Wave Observatory (LIGO). We discuss the principles of this scheme and show methods that allow sensing and control signals to be derived. Experimental verification was carried out in three benchtop experiments that are introduced. We present the implications of the results from these experiments for Advanced LIGO and other future interferometric gravitational-wave detectors

    Continuous Leg Cycling Ergometry Prescribed at Identical Relative Power Output Elicits Different Physiological Responses Versus Arm Cycle Ergometry

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    PURPOSE: The aim of this study was to compare physiological and perceptual responses to progressive moderate intensity continuous exercise (MICE) between leg (LCE) and arm cycle ergometry (ACE). METHODS: Seventeen active men and women (age and percent body fat = 26 ± 7 yr and 18 ± 3 %) initially performed graded exercise on each modality to assess maximal oxygen uptake (VO2max) and peak power output (PPO). Using a randomized crossover design, they subsequently performed 45 min of MICE consisting of three 15 min bouts at 20, 40, and 60 % PPO on each modality. Gas exchange data (VO2, VCO2, VE, and respiratory exchange ratio (RER), heart rate (HR), blood lactate concentration (BLa), affective valence, and rating of perceived exertion (RPE) were acquired during each bout. RESULTS: Compared to ACE, LCE revealed significantly higher (p \u3c 0.05) peak (94 ± 6 vs. 88 ± 9 %HRmax, d = 0.81) and mean HR (73 ± 6 vs. 66 ± 6 %HRmax, d = 1.20) and VO2 (54 ± 5 vs. 50 ± 7 %VO2max, d = 0.68). Time spent above 70 (22 ± 7 vs. 15 ± 8 min, d = 1.03) and 80 %HRmax (15 ± 6 vs. 9 ± 6 min, d = 1.04) was significantly greater with LCE versus ACE. LCE revealed significantly higher BLa versus ACE (5.5 ± 2.0 vs. 4.7 ± 1.5 mM, d = 0.48). CONCLUSIONS: These results exhibit that progressive leg cycling at identical intensities elicits a greater cardiometabolic stimulus than arm ergometry. Moreover, leg cycling leads to greater duration spent at intensities between 70 – 89 %VO2max which may have application to selecting specific exercise modes when prescribing MICE to increase cardiorespiratory fitness. Lastly, use of %PPO led to participants being classified in different intensity domains which merits prescribing MICE according to various threshold measures rather than relative intensities acquired from incremental exercise
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