1,176 research outputs found
The nature of the [Cāii] emission in dusty star-forming galaxies from the SPT survey
We present [Cāii] observations of 20 strongly lensed dusty star-forming galaxies at 2.1 20āmJy) from the South Pole Telescope (SPT) survey, with far-infrared (FIR) luminosities determined from extensive photometric data. The [Cāii] line is robustly detected in 17 sources, all but one being spectrally resolved. 11 out of 20 sources observed in [Cāii] also have low-J CO detections from Australia Telescope Compact Array. A comparison with mid- and high-J CO lines from Atacama Large Millimeter/submillimeter Array reveals consistent [Cāii] and CO velocity profiles, suggesting that there is little differential lensing between these species. The [Cāii], low-J CO and FIR data allow us to constrain the properties of the interstellar medium. We find [Cāii] to CO(1ā0) luminosity ratios in the SPT sample of 5200 Ā± 1800, with significantly less scatter than in other samples. This line ratio can be best described by a medium of [Cāii] and CO emitting gas with a higher [Cāii] than CO excitation temperature, high CO optical depth Ļ_CO(1ā0) ā« 1, and low to moderate [Cāii] optical depth Ļ_[CII]ā² 1. The geometric structure of photodissociation regions allows for such conditions
Oxidative stress influences positive strand RNA virus genome synthesis and capping
AbstractFlaviviruses are 5ā² capped positive-stranded RNA viruses that replicate their genomes within endoplasmic reticulum-derived vesicles. Flaviviruses are well known to induce oxidative stress late in infection but it is unknown if oxidative stress plays a positive role in the viral RNA replication cycle. We therefore examined how oxidation affects flavivirus RNA replication. We found that antioxidant treatment reduced virus production, reduced the viral positive-to-negative strand RNA ratio, and resulted in the accumulation of uncapped positive-sense viral RNAs. Treatment of the NS5 RNA capping enzyme in vitro with oxidizing agents enhanced guanylyltransferase activity, indicating that the guanylyltransferase function of the flavivirus NS5 RNA capping enzyme is activated by oxidative conditions. Antioxidant treatment also reduced alphavirus RNA replication and protein expression while enhancing nsP1 capping activity. These findings suggest that RNA viruses may utilize oxidative stress induced during infection to help temporally control genome RNA capping and genome replication
Sox9 Transcriptionally Represses Spp1 to Prevent Matrix Mineralization in Maturing Heart Valves and Chondrocytes
Sox9 is an SRY-related transcription factor required for expression of cartilaginous genes in the developing skeletal system and heart valve structures. In contrast to positively regulating cartilaginous matrix, Sox9 also negatively regulates matrix mineralization associated with bone formation. While the transcriptional activation of Sox9 target genes during chondrogenesis has been characterized, the mechanisms by which Sox9 represses osteogenic processes are not so clear. Using ChIP-on-chip and luciferase assays we show that Sox9 binds and represses transactivation of the osteogenic glycoprotein Spp1. In addition, Sox9 knockdown in post natal mouse heart valve explants and rib chondrocyte cultures promotes Spp1 expression and matrix mineralization, while attenuating expression of cartilage genes Type II Collagen and Cartilage Link Protein. Further, we show that Spp1 is required for matrix mineralization induced by Sox9 knockdown. These studies provide insights into the molecular mechanisms by which Sox9 prevents pathologic matrix mineralization in tissues that must remain cartilaginous
Characterization of skeletal phenotypes of TRĪ±1(PV) and TRĪ²(PV) mutant mice: implications for tissue thyroid status and T3 target gene expression
Bone development is extremely sensitive to alterations in thyroid status. Recently, we analyzed the skeletal phenotypes of mice with the dominant negative resistance to thyroid hormone (RTH) mutation PV targeted to either the thyroid hormone receptor (TR) Ī±1 or Ī² gene. This perspective summarizes our findings to date and explores the wider implications for thyroid status and T3 target gene expression in individual tissues
Pregnancy and childbirth in English prisons : institutional ignominy and the pains of imprisonment
Ā© 2020 The Authors. Sociology of Health & Illness published by John Wiley & Sons Ltd on behalf of Foundation for SHIL.With a prison population of approximately 9000 women in England, it is estimated that approximately 600 pregnancies and 100 births occur annually. Despite an extensive literature on the sociology of reproduction, pregnancy and childbirth among women prisoners is underāresearched. This article reports an ethnographic study in three English prisons undertaken in 2015ā2016, including interviews with 22 prisoners, six women released from prison and 10 staff members. Pregnant prisoners experience numerous additional difficulties in prison including the ambiguous status of a pregnant prisoner, physical aspects of pregnancy and the degradation of the handcuffed or chained prisoner during visits to the more public setting of hospital. This article draws on Erving Goffman's concepts of closed institutions, dramaturgy and mortification of self, Crewe et al.'s work on the gendered pains of imprisonment and Crawley's notion of āinstitutional thoughtlessnessā, and proposes a new concept of institutional ignominy to understand the embodied situation of the pregnant prisoner.Peer reviewe
SPT0346-52: Negligible AGN Activity in a Compact, Hyper-starburst Galaxy at z = 5.7
We present Chandra ACIS-S and ATCA radio continuum observations of the
strongly lensed dusty, star-forming galaxy SPT-S J034640-5204.9 (hereafter
SPT0346-52) at = 5.656. This galaxy has also been observed with ALMA, HST,
Spitzer, Herschel, APEX, and the VLT. Previous observations indicate that if
the infrared (IR) emission is driven by star formation, then the inferred
lensing-corrected star formation rate ( 4500 M_{\sun} yr) and
star formation rate surface density ( 2000 M_{\sun}
{yr^{-1}} {kpc^{-2}}) are both exceptionally high. It remained unclear from
the previous data, however, whether a central active galactic nucleus (AGN)
contributes appreciably to the IR luminosity. The {\it Chandra} upper limit
shows that SPT0346-52 is consistent with being star-formation dominated in the
X-ray, and any AGN contribution to the IR emission is negligible. The ATCA
radio continuum upper limits are also consistent with the FIR-to-radio
correlation for star-forming galaxies with no indication of an additional AGN
contribution. The observed prodigious intrinsic IR luminosity of (3.6
0.3) 10 L_{\sun} originates almost solely from vigorous star
formation activity. With an intrinsic source size of 0.61 0.03 kpc,
SPT0346-52 is confirmed to have one of the highest of any known
galaxy. This high , which approaches the Eddington limit for a
radiation pressure supported starburst, may be explained by a combination of
very high star formation efficiency and gas fraction.Comment: 8 pages, 6 figures, accepted for publication in Ap
The hidden circumgalactic medium
The cycling of baryons in and out of galaxies is what ultimately drives
galaxy formation and evolution. The circumgalactic medium (CGM) represents the
interface between the interstellar medium and the cosmic web, hence its
properties are directly shaped by the baryon cycle. Although traditionally the
CGM is thought to consist of warm and hot gas, recent breakthroughs are
presenting a new scenario according to which an important fraction of its mass
may reside in the cold atomic and molecular phase. This would represent fuel
that is readily available for star formation, with crucial implications for
feeding and feedback processes in galaxies. However, such cold CGM, especially
in local galaxies where its projected size on sky is expected to be of several
arcminutes, cannot be imaged by ALMA due to interferometric spatial scale
filtering of large-scale structures. We show that the only way to probe the
multiphase CGM including its coldest component is through a large (e.g. 50-m)
single dish (sub-)mm telescope.Comment: Science white paper submitted to the Astro2020 Decadal Surve
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