822 research outputs found

    Development of advanced digital techniques for data acquisition processing and communication Interim scientific report

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    Image correlation and computerized simulation applied to data acquisition and imaging technique

    PCM telemetry data compression study, phase II Quarterly report, 25 Nov. 1965 - 25 Feb. 1966

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    Model analyses and computer simulations used in data compression study for improved pulse code modulation telemetry link

    The development of advanced digital techniques for data acquisition processing and communication Interim scientific report

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    Digital techniques for characterization of image sources, second order interpolation, sensitivity of compressed pictures to error, and simulation of mapping technique

    A Recessive Mutation Resulting in a Disabling Amino Acid Substitution (T194R) in the LHX3 Homeodomain Causes Combined Pituitary Hormone Deficiency

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    Background/Aims: Recessive mutations in the LHX3 homeodomain transcription factor gene are associated with developmental disorders affecting the pituitary and nervous system. We describe pediatric patients with combined pituitary hormone deficiency (CPHD) who harbor a novel mutation in LHX3. Methods: Two female siblings from related parents were examined. Both patients had neonatal complications. The index patient had CPHD featuring deficiencies of GH, LH, FSH, PRL, and TSH, with later onset of ACTH deficiency. She also had a hypoplastic anterior pituitary, respiratory distress, hearing impairment, and limited neck rotation. The LHX3 gene was sequenced and the biochemical properties of the predicted altered proteins were characterized. Results: A novel homozygous mutation predicted to change amino acid 194 from threonine to arginine (T194R) was detected in both patients. This amino acid is conserved in the DNA-binding homeodomain. Computer modeling predicted that the T194R change would alter the homeodomain structure. The T194R protein did not bind tested LHX3 DNA recognition sites and did not activate the a-glycoprotein and PRL target genes. Conclusion: The T194R mutation affects a critical residue in the LHX3 protein. This study extends our understanding of the phenotypic features, molecular mechanism, and developmental course associated with mutations in the LHX3 gene. copyright (C) 2012 S. Karger AG, Base

    PCM telemetry data compression study, phase 1 Final report, 15 Sep. 1964 - 15 Aug. 1965

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    Pulse Code Modulation /PCM/ telemetry data compression study using S-6 Explorer XVII DAT

    A Proto-Galaxy Candidate at z=2.7 Discovered by Its Young Stellar Population

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    A protogalaxy candidate at z=2.72 has been discovered serendipitously by the CNOC cluster redshift survey. The candidate is an extremely luminous (V=20.5 mag, absolute mag -26) and well resolved disk-like galaxy. The redshift is identified from a dozen strong UV absorption lines. No emission lines are found between 1000 and 2000A (rest), including Ly alpha. The photometric data fit the spectral energy distributions of a stellar population from 400 million years to an arbitrarily young age, dependent on the amount of dust extinction. However, the presence of a strong P-Cygni profile in CIV~indicates that a very substantial component of the stellar population must be younger than ~ 10 Myr. We interpret this object as an early-type galaxy observed within about 100 million years of the initial burst of star formation which created most of its stellar mass. Because of the resolved, regular, and smooth nature of the object, it is unlikely that the high luminosity is due to gravitational lensing.Comment: 31 page, Latex file with 9 encapsulated figures, requiring aasppt.sty and epsf.sty (included). Full uuencoded ps file available from: http://manaslu.astro.utoronto.ca/~carlberg/cnoc/general.html Accepted by Astronomical Journal, in press, May 199

    The structural properties and star formation history of Leo T from deep LBT photometry

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    We present deep, wide-field g and r photometry of the transition type dwarf galaxy Leo T, obtained with the blue arm of the Large Binocular Telescope. The data confirm the presence of both very young (5 Gyr) stars. We study the structural properties of the old and young stellar populations by preferentially selecting either population based on their color and magnitude. The young population is significantly more concentrated than the old population, with half-light radii of 104+-8 and 148+-16 pc respectively, and their centers are slightly offset. Approximately 10% of the total stellar mass is estimated to be represented by the young stellar population. Comparison of the color-magnitude diagram (CMD) with theoretical isochrones as well as numerical CMD-fitting suggest that star formation began over 10 Gyr ago and continued in recent times until at least a few hundred Myr ago. The CMD-fitting results are indicative of two distinct star formation bursts, with a quiescent period around 3 Gyr ago, albeit at low significance. The results are consistent with no metallicity evolution and [Fe/H] ~ -1.5 over the entire age of the system. Finally, the data show little if any sign of tidal distortion of Leo T.Comment: 8 pages, 9 figures, some small textual changes, accepted for publication in the Astrophysical Journa
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