5,953 research outputs found

    Spatially Resolved Gas Kinematics within a Lyα\alpha Nebula: Evidence for Large-scale Rotation

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    We use spatially extended measurements of Lyα\alpha as well as less optically thick emission lines from an ≈\approx80 kpc Lyα\alpha nebula at z≈1.67z\approx1.67 to assess the role of resonant scattering and to disentangle kinematic signatures from Lyα\alpha radiative transfer effects. We find that the Lyα\alpha, CIV, HeII, and CIII] emission lines all tell a similar story in this system, and that the kinematics are broadly consistent with large-scale rotation. First, the observed surface brightness profiles are similar in extent in all four lines, strongly favoring a picture in which the Lyα\alpha photons are produced in situ instead of being resonantly scattered from a central source. Second, we see low kinematic offsets between Lyα\alpha and the less optically thick HeII line (∼\sim100-200 km s−1^{-1}), providing further support for the argument that the Lyα\alpha and other emission lines are all being produced within the spatially extended gas. Finally, the full velocity field of the system shows coherent velocity shear in all emission lines: ≈\approx500 km s−1^{-1} over the central ≈\approx50 kpc of the nebula. The kinematic profiles are broadly consistent with large-scale rotation in a gas disk that is at least partially stable against collapse. These observations suggest that the Lyα\alpha nebula represents accreting material that is illuminated by an offset, hidden AGN or distributed star formation, and that is undergoing rotation in a clumpy and turbulent gas disk. With an implied mass of M(<R=20 kpc)∼3×1011\sim3\times10^{11} M⊙M_{\odot}, this system may represent the early formation of a large Milky Way mass galaxy or galaxy group.Comment: Accepted to ApJ; 25 pages in emulateapj format; 15 figures, 4 table

    An LED-based Flasher System for VERITAS

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    We describe a flasher system designed for use in monitoring the gains of the photomultiplier tubes used in the VERITAS gamma-ray telescopes. This system uses blue light-emitting diodes (LEDs) so it can be operated at much higher rates than a traditional laser-based system. Calibration information can be obtained with better statistical precision with reduced loss of observing time. The LEDs are also much less expensive than a laser. The design features of the new system are presented, along with measurements made with a prototype mounted on one of the VERITAS telescopes.Comment: Accepted for publication in Nuclear Instruments and Methods in Physics Research

    The Stripe 82 1-2 GHz Very Large Array Snapshot Survey: Multiwavelength Counterparts

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    We have combined spectrosopic and photometric data from the Sloan Digital Sky Survey (SDSS) with 1.41.4 GHz radio observations, conducted as part of the Stripe 82 1−21-2 GHz Snapshot Survey using the Karl G. Jansky Very Large Array (VLA), which covers ∼100\sim100 sq degrees, to a flux limit of 88 μ\muJy rms. Cross-matching the 11 76811\,768 radio source components with optical data via visual inspection results in a final sample of 4 7954\,795 cross-matched objects, of which 1 9961\,996 have spectroscopic redshifts and 2 7992\,799 objects have photometric redshifts. Three previously undiscovered Giant Radio Galaxies (GRGs) were found during the cross-matching process, which would have been missed using automated techniques. For the objects with spectroscopy we separate radio-loud Active Galactic Nuclei (AGN) and star-forming galaxies (SFGs) using three diagnostics and then further divide our radio-loud AGN into the HERG and LERG populations. A control matched sample of HERGs and LERGs, matched on stellar mass, redshift and radio luminosity, reveals that the host galaxies of LERGs are redder and more concentrated than HERGs. By combining with near-infrared data, we demonstrate that LERGs also follow a tight K−zK-z relationship. These results imply the LERG population are hosted by population of massive, passively evolving early-type galaxies. We go on to show that HERGs, LERGs, QSOs and star-forming galaxies in our sample all reside in different regions of a WISE colour-colour diagram. This cross-matched sample bridges the gap between previous `wide but shallow' and `deep but narrow' samples and will be useful for a number of future investigations.Comment: 17 pages, 19 figures. Resubmitted to MNRAS after the initial comment

    Very small deletions within the NESP55 gene in pseudohypoparathyroidism type 1b

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    Pseudohypoparathyroidism (PHP) is caused by reduced expression of genes within the GNAS cluster, resulting in parathormone resistance. The cluster contains multiple imprinted transcripts, including the stimulatory G protein α subunit (Gs-α) and NESP55 transcript preferentially expressed from the maternal allele, and the paternally expressed XLas, A/B and antisense transcripts. PHP1b can be caused by loss of imprinting affecting GNAS A/B alone (associated with STX16 deletion), or the entire GNAS cluster (associated with deletions of NESP55 in a minority of cases). We performed targeted genomic next-generation sequencing (NGS) of the GNAS cluster to seek variants and indels underlying PHP1b. Seven patients were sequenced by hybridisation-based capture and fourteen more by long-range PCR and transposon-mediated insertion and sequencing. A bioinformatic pipeline was developed for variant and indel detection. In one family with two affected siblings, and in a second family with a single affected individual, we detected maternally inherited deletions of 40 and 33 bp, respectively, within the deletion previously reported in rare families with PHP1b. All three affected individuals presented with atypically severe PHP1b; interestingly, the unaffected mother in one family had the detected deletion on her maternally inherited allele. Targeted NGS can reveal sequence changes undetectable by current diagnostic methods. Identification of genetic mutations underlying epigenetic changes can facilitate accurate diagnosis and counselling, and potentially highlight genetic elements critical for normal imprint settin

    Tacrolimus Toxicity Associated with Concomitant Metoclopramide Therapy

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90417/1/phco.24.5.532.33357.pd

    Regulation of COX-2 transcription in a colon cancer cell line by Pontin52/TIP49a

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    Cyclooxygenase-2 (COX-2) is expressed early in colon carcinogenesis and is known to play a crucial role in the progress of the disease. Here we show that the regulation of the expression of this enzyme in a colon cancer cell line, and in patients, is associated with overexpression of the Wnt pathway-associated proteins, Pontin52/TIP49a and LEF-1. Recently shown to be essential for transformation via the c-Myc pathway, Pontin52/TIP49a promotes COX-2 expression in tissue culture and is overexpressed in colon cancer tissue, co-localizing with COX-2 expression in transformed tissue, relative to paired normal tissue
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