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Steffen J.H.,Fermilab Center for Particle Astrophysics | Hotchkiss J.,Hotchkiss Industries
Journal of Air Transport Management | Year: 2012

We report the results of an experimental comparison of airplane boarding methods. This test was conducted in a mock Boeing 757 fuselage, located on a Southern California soundstage, with 12 rows of six seats and a single aisle. Five methods were tested using 72 passengers of various ages. We found a significant reduction in the boarding times of optimized methods over traditional methods. These improved methods, if properly implemented, offer the potential for significant savings to airline companies. © 2011 Elsevier Ltd. Source

Ilic S.,University Paris - Sud | Ilic S.,University of Sussex | Kunz M.,University of Sussex | Kunz M.,University of Geneva | And 3 more authors.
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2010

Traditionally, inflationary models are analyzed in terms of parameters such as the scalar spectral index ns and the tensor to scalar ratio r, while dark energy models are studied in terms of the equation of state parameter w. Motivated by the fact that both deal with periods of accelerated expansion, we study the evolution of w during inflation, in order to derive observational constraints on its value during an earlier epoch likely dominated by a dynamic form of dark energy. We find that the cosmic microwave background and large-scale structure data is consistent with winflation=-1 and provides an upper limit of 1+w 0.02. Nonetheless, an exact de Sitter expansion with a constant w=-1 is disfavored since this would result in ns=1. © 2010 The American Physical Society. Source

Agol E.,University of Washington | Agol E.,University of California at Santa Barbara | Cowan N.B.,University of Washington | Knutson H.A.,University of California at Berkeley | And 4 more authors.
Astrophysical Journal | Year: 2010

We present observations of six transits and six eclipses of the transiting planet system HD 189733 taken with the Spitzer Space Telescope's Infrared Array Camera (IRAC) at 8μm, as well as a re-analysis of previously published data. We use several novel techniques in our data analysis, the most important of which is a new correction for the detector "ramp" variation with a double-exponential function, which performs better and is a better physical model for this detector variation. Our main scientific findings are (1) an upper limit on the variability of the dayside planet flux of 2.7% (68% confidence); (2) the most precise set of transit times measured for a transiting planet, with an average accuracy of 3 s; (3) a lack of transit-timing variations, excluding the presence of second planets in this system above 20% of the mass of Mars in low-order mean-motion resonance at 95% confidence; (4) a confirmation of the planet's phase variation, finding the night side is 64% as bright as the day side, as well as an upper limit on the nightside variability of 17% (68% confidence); (5) a better correction for stellar variability at 8μm causing the phase function to peak 3.5 hr before secondary eclipse, confirming that the advection and radiation timescales are comparable at the 8μm photosphere; (6) variation in the depth of transit, which possibly implies variations in the surface brightness of the portion of the star occulted by the planet, posing a fundamental limit on non-simultaneous multi-wavelength transit absorption measurements of planet atmospheres; (7) a measurement of the infrared limb darkening of the star, which is in good agreement with stellar atmosphere models; (8) an offset in the times of secondary eclipse of 69 s, which is mostly accounted for by a 31 s light-travel time delay and 33 s delay due to the shift of ingress and egress by the planet hot spot; this confirms that the phase variation is due to an offset hot spot on the planet; (9) a retraction of the claimed eccentricity of this system due to the offset of secondary eclipse, which is now just an upper limit; and (10) high-precision measurements of the parameters of this system. These results were enabled by the exquisite photometric precision of Spitzer IRAC; for repeat observations the scatter is less than 0.35 mmag over the 590 day timescale of our observations after decorrelating with detector parameters. © 2010. The American Astronomical Society. All rights reserved. Source

Estrada J.,Fermilab Center for Particle Astrophysics
Journal of Physics: Conference Series | Year: 2010

There is currently vast evidence for Dark Matter (DM) from astronomical observations. However, in spite of tremendous efforts by large experimental groups, there is no confirmed direct detection of the dark matter in our galaxy. Recent experimental results and theoretical developments suggest the possibility of a DM particle with mass below 10 GeV, such a particle would escape most of the direct searches due to the large thresholds for the detection of nuclear recoils typically used. In this work we study the possibility of a new Dark Matter search with an unprecedented low threshold for the detection of nuclear recoils using high-resistivity CCD detectors (hr-CCD). Due their extremely low readout noise and the relatively large active mass, these detectors present a unique opportunity in this field. © 2010 IOP Publishing Ltd. Source

Szypryt P.,University of California at Santa Barbara | Duggan G.E.,University of California at Santa Barbara | Duggan G.E.,California Institute of Technology | Mazin B.A.,University of California at Santa Barbara | And 10 more authors.
Monthly Notices of the Royal Astronomical Society | Year: 2014

AM Canum Venaticorum (AM CVn) stars belong to a class of ultracompact, short-period binaries with spectra dominated largely by helium. SDSS J0926+3624 is of particular interest as it is the first observed eclipsing AM CVn system. We observed SDSS J0926+3624 with the Array Camera for Optical to Near-IR Spectrophotometry (ARCONS) at the Palomar 200" telescope. ARCONS uses a relatively new type of energy-resolved photon counters called Microwave Kinetic Inductance Detectors. ARCONS, sensitive to radiation from 350 to 1100 nm, has a time resolution of several microseconds and can measure the energy of a photon to ̃10 per cent. We present the light curves for these observations and examine changes in orbital period from prior observations. Using a quadratic ephemeris model, wemeasure a period rate of change ?P = (3.07 ± 0.56) × 10-13. In addition, we use the high timing resolution of ARCONS to examine the system's high-frequency variations and search for possible quasiperiodic oscillations (QPOs). Finally, we use the instrument's spectral resolution to examine the light curves in various wavelength bands. We do not find any high-frequency QPOs or significant spectral variability throughout an eclipse. © 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. Source

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