Browsing MIT Open Access Articles by Title
Now showing items 31895-31914 of 32066
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X-band radar based SLAM in Singapore's off-shore environment
(Institute of Electrical and Electronics Engineers (IEEE), 2010)This paper presents a simultaneous localisation and mapping (SLAM) algorithm implemented on an autonomous sea kayak with a commercial off-the-shelf X-band marine radar mounted. The Autonomous Surface Craft (ASC) was driven ... -
X-linked H3K27me3 demethylase Utx is required for embryonic development in a sex-specific manner
(National Academy of Sciences (U.S.), 2012-07)Embryogenesis requires the timely and coordinated activation of developmental regulators. It has been suggested that the recently discovered class of histone demethylases (UTX and JMJD3) that specifically target the ... -
X-Pipeline: an analysis package for autonomous gravitational-wave burst searches
(Institute of Physics Publishing, 2010-05)Autonomous gravitational-wave searches—fully automated analyses of data that run without human intervention or assistance—are desirable for a number of reasons. They are necessary for the rapid identification of ... -
X-ray absorption spectroscopy elucidates the impact of structural disorder on electron mobility in amorphous zinc-tin-oxide thin films
(American Institute of Physics (AIP), 2014-06)We investigate the correlation between the atomic structures of amorphous zinc-tin-oxide (a-ZTO) thin films grown by atomic layer deposition (ALD) and their electronic transport properties. We perform synchrotron-based ... -
X-ray analysis of butirosin biosynthetic enzyme BtrN redefines structural motifs for AdoMet radical chemistry
(National Academy of Sciences (U.S.), 2013-10)The 2-deoxy-scyllo-inosamine (DOIA) dehydrogenases are key enzymes in the biosynthesis of 2-deoxystreptamine–containing aminoglycoside antibiotics. In contrast to most DOIA dehydrogenases, which are NAD-dependent, the DOIA ... -
X-ray and electron diffraction studies of superlattices and long-range three-dimensional Na ordering in gamma-Na[subscript x]CoO[subscript 2] (x=0.71 and 0.84)
(American Physical Society, 2009-01)We have recently demonstrated that x=0.71 and 0.84 are the two most stable single-phase compounds above x=0.5 in gamma-Na[subscript x]CoO[subscript 2] [G. J. Shu et al., Phys. Rev. B 76, 184115 (2007); F. C. Chou et al., ... -
X-RAY AND NEAR-INFRARED OBSERVATIONS OF THE OBSCURED ACCRETING PULSAR IGR J18179–1621
(IOP Publishing, 2012-09)IGR J18179–1621 is an obscured accreting X-ray pulsar discovered by INTEGRAL on 2012 February 29. We report on our 20 ks Chandra-High Energy Transmission Gratings Spectrometer observation of the source performed on 2012 ... -
X-ray and optical flux ratio anomalies in quadruply lensed quasars. II. Mapping the dark matter content in elliptical galaxies
(Institute of Physics Publishing, 2012-01)We present a microlensing analysis of 61 Chandra observations of 14 quadruply lensed quasars. X-ray flux measurements of the individual quasar images give a clean determination of the microlensing effects in the lensing ... -
X-RAY AND OPTICAL STUDY OF LOW CORE DENSITY GLOBULAR CLUSTERS NGC6144 AND E3
(IOP Publishing, 2010-03)We report on the Chandra X-ray Observatory and Hubble Space Telescope (HST) observations of two low core-density globular clusters, NGC6144 and E3. By comparing the number of X-ray sources inside the half-mass radius to ... -
X-RAY AND RADIO VARIABILITY OF M31*, THE ANDROMEDA GALAXY NUCLEAR SUPERMASSIVE BLACK HOLE
(Institute of Physics/American Astronomical Society, 2010-02)We confirm our earlier tentative detection of M31* in X-rays and measure its light curve and spectrum. Observations in 2004-2005 find M31* rather quiescent in the X-ray and radio. However, X-ray observations in 2006-2007 ... -
X-RAY CAVITIES IN A SAMPLE OF 83 SPT-SELECTED CLUSTERS OF GALAXIES: TRACING THE EVOLUTION OF AGN FEEDBACK IN CLUSTERS OF GALAXIES OUT TO z = 1.2
(IOP Publishing, 2015-05)X-ray cavities are key tracers of mechanical (or radio mode) heating arising from the active galactic nuclei (AGNs) in brightest cluster galaxies (BCGs). We report on a survey for X-ray cavities in 83 massive, high-redshift ... -
X-RAY EJECTA KINEMATICS OF THE GALACTIC CORE-COLLAPSE SUPERNOVA REMNANT G292.0+1.8
(IOP Publishing, 2015-02)We report on the results from the analysis of our 114 ks Chandra High Energy Transmision Grating Spectrometer observation of the Galactic core-collapse supernova remnant G292.0+1.8. To probe the three-dimensional structure ... -
X-RAY EMISSION AND CORONA OF THE YOUNG INTERMEDIATE-MASS BINARY theta(1) Ori E
(American Astronomical Society, 2009-11)θ(1) Ori E is a young, moderate mass binary system, a rarely observed case of spectral-type G-giants of about 3 solar masses, which are still collapsing toward the main sequence, where they presumably become X-ray faint. ... -
X-RAY EMISSION FROM TWO INFRARED-SELECTED GALAXY CLUSTERS AT z > 1.4 IN THE IRAC SHALLOW CLUSTER SURVEY
(Institute of Physics/American Astronomical Society, 2011-05)We report the X-ray detection of two z > 1.4 infrared-selected galaxy clusters from the IRAC Shallow Cluster Survey (ISCS). We present new data from the Hubble Space Telescope and the W. M. Keck Observatory that spectroscopically ... -
X-RAY FLARES OF EV Lac: STATISTICS, SPECTRA, AND DIAGNOSTICS
(Institute of Physics/American Astronomical Society, 2010-11)We study the spectral and temporal behavior of X-ray flares from the active M dwarf EV Lac in 200 ks of exposure with the Chandra/HETGS. We derive flare parameters by fitting an empirical function which characterizes the ... -
THE X-RAY FLUX DISTRIBUTION OF SAGITTARIUS A* AS SEEN BY CHANDRA
(Institute of Physics/American Astronomical Society, 2015-01)We present a statistical analysis of the X-ray flux distribution of Sgr A* from the Chandra X-Ray Observatory's 3 Ms Sgr A* X-ray Visionary Project in 2012. Our analysis indicates that the observed X-ray flux distribution ... -
X-ray imaging crystal spectroscopy for use in plasma transport research
(American Institute of Physics (AIP), 2012-11)This research describes advancements in the spectral analysis and error propagation techniques associated with x-ray imaging crystal spectroscopy (XICS) that have enabled this diagnostic to be used to accurately constrain ... -
AN X-RAY IMAGING SURVEY OF QUASAR JETS: TESTING THE INVERSE COMPTON MODEL
(IOP Publishing, 2011-03)We present results from continued Chandra X-ray imaging and spectroscopy of a flux-limited sample of flat spectrum radio-emitting quasars with jet-like extended structure. X-rays are detected from 24 of the 39 jets observed ... -
The X-ray Microcalorimeter Spectrometer onboard of IXO
(Institute of Electrical and Electronics Engineers, 2010-06)One of the instruments on the International X-ray Observatory (IXO), under study with NASA, ESA and JAXA, is the X-ray Microcalorimeter Spectrometer (XMS). This instrument, which will provide high spectral resolution images, ... -
X-Ray Modeling of Very Young Early-Type Stars in the Orion Trapezium: Signatures of Magnetically Confined Plasmas and Evolutionary Implications
(IOP Publishing, 2003-09)The Orion Trapezium is one of the youngest and closest star-forming regions within our Galaxy. With a dynamic age of ~3 × 10[superscript 5] yr, it harbors a number of very young hot stars, which likely are on the zero-age ...
