373 research outputs found

    Grinding the Orange Axe

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    Deep Near-IR Surface Photometry of 57 Galaxies in the Local Sphere of Influence

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    We present H-band surface photometry of 57 galaxies drawn from the Local Sphere of Influence (LSI) with distances of less than 10 Mpc from the Milky Way. The images with a typical surface brightness limit 4 mag fainter than 2MASS (24.5 mag arcsec^-2 < sb_lim < 26 mag arcsec ^-2) have been obtained with IRIS2 on the 3.9 m Anglo-Australian Telescope. A total of 22 galaxies that remained previously undetected in the near-IR and potentially could have been genuinely young galaxies were found to have an old stellar population with a star density 1-2 magnitudes below the 2MASS detection threshold. The cleaned near-IR images reveal the morphology and extent of many of the galaxies for the first time. For all program galaxies, we derive radial luminosity profiles, ellipticities, and position angles, together with global parameters such as total magnitude, mean effective surface brightness and half-light radius. Our results show that 2MASS underestimates the total magnitude of galaxies with _eff between 18-21 mag arcsec^-2 by up to 2.5 mag. The Sersic parameters best describing the observed surface brightness profiles are also presented. Adopting accurate galaxy distances and a H-band mass-to-light ratio of Upsilon_H=1.0 +/- 0.4, the LSI galaxies are found to cover a stellar mass range of 5.6 < log_10 (M_stars) < 11.1. The results are discussed along with previously obtained optical data. Our sample of low luminosity galaxies is found to follow closely the optical-infrared B versus H luminosity relation defined by brighter galaxies with a slope of 1.14 +/- 0.02 and scatter of 0.3 magnitudes. Finally we analyse the luminosity - surface brightness relation to determine an empirical mass-to-light ratio of Upsilon_H=0.78 +/- 0.08 for late-type galaxies in the H-band.Comment: Accepted by AJ. High resolution version available at http://www.mso.anu.edu.au/~emma/KirbyHband.pd

    Tubular cell and keratinocyte single-cell transcriptomics applied to lupus nephritis reveal type I IFN and fibrosis relevant pathways.

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    The molecular and cellular processes that lead to renal damage and to the heterogeneity of lupus nephritis (LN) are not well understood. We applied single-cell RNA sequencing (scRNA-seq) to renal biopsies from patients with LN and evaluated skin biopsies as a potential source of diagnostic and prognostic markers of renal disease. Type I interferon (IFN)-response signatures in tubular cells and keratinocytes distinguished patients with LN from healthy control subjects. Moreover, a high IFN-response signature and fibrotic signature in tubular cells were each associated with failure to respond to treatment. Analysis of tubular cells from patients with proliferative, membranous and mixed LN indicated pathways relevant to inflammation and fibrosis, which offer insight into their histologic differences. In summary, we applied scRNA-seq to LN to deconstruct its heterogeneity and identify novel targets for personalized approaches to therapy

    The European Registered Toxicologist (ERT) : Current status and prospects for advancement

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    Acknowledgements We would like to thank the participants of the five workshops in which the issues presented in this paper were discussed and the revised guidelines prepared, as well as the EUROTOX Executive Committee and the societies of toxicology of Sweden, the Netherlands, Switzerland, Austria and France for their support which allowed the workshops to take place.Peer reviewedPostprin

    Gas Metallicities in the Extended Disks of NGC 1512 and NGC 3621. Chemical Signatures of Metal Mixing or Enriched Gas Accretion?

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    (Abridged) We have obtained spectra of 135 HII regions located in the inner and extended disks of the spiral galaxies NGC 1512 and NGC 3621, spanning the range of galactocentric distances 0.2-2 x R25 (from 2-3 kpc to 18-25 kpc). We find that the excitation properties of nebulae in the outer (R>R25) disks are similar to those of the inner disks, but on average younger HII regions tend to be selected in the bright inner disks. Reddening by dust is not negligible in the outer disks, and subject to significant large-scale spatial variations. For both galaxies the radial abundance gradient flattens to a constant value outside of the isophotal radius. The outer disk O/H abundance ratio is highly homogeneous, with a scatter of only ~0.06 dex. Based on the excitation and chemical (N/O ratio) analysis we find no compelling evidence for variations in the upper initial mass function of the ionizing clusters of extended disks. The O/H abundance in the outer disks of the target galaxies corresponds to 35% of the solar value (or higher, depending on the metallicity diagnostic). This conflicts with the notion that metallicities in extended disks of spiral galaxies are necessarily low. The observed metal enrichment cannot be produced with the current level of star formation. We discuss the possibility that metal transport mechanisms from the inner disks lead to metal pollution of the outer disks. Gas accretion from the intergalactic medium, enriched by outflows, offers an alternative solution.Comment: Accepted for publication in the Astrophysical Journa

    Development of a hard X-ray delay line for X-ray photon correlation spectroscopy and jitter-free pump–probe experiments at X-ray free-electron laser sources

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    A prototype device capable of splitting an X-ray pulse into two adjustable fractions, delaying one of them with the aim of performing split pulse X-ray photon correlation spectroscopy and pump–probe type studies was designed and manufactured. Time delays up to 2.95 ns have been demonstrated. The achieved contrast values of 56% indicate a feasibility of performing coherence-based experiments with the delay line

    Sexual Size Dimorphism and Body Condition in the Australasian Gannet

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    Funding: The research was financially supported by the Holsworth Wildlife Research Endowment. Acknowledgments We thank the Victorian Marine Science Consortium, Sea All Dolphin Swim, Parks Victoria, and the Point Danger Management Committee for logistical support. We are grateful for the assistance of the many field volunteers involved in the study.Peer reviewedPublisher PD

    Recommendations for the surveillance of education and employment outcomes in survivors of childhood, adolescent, and young adult cancer: A report from the International Late Effects of Childhood Cancer Guideline Harmonization Group.

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    Educational achievement and employment outcomes are critical indicators of quality of life in survivors of childhood, adolescent, and young adult (CAYA) cancer. This review is aimed at providing an evidence-based clinical practice guideline (CPG) with internationally harmonized recommendations for the surveillance of education and employment outcomes in survivors of CAYA cancer diagnosed before the age of 30 years. The CPG was developed by a multidisciplinary panel under the umbrella of the International Late Effects of Childhood Cancer Guideline Harmonization Group. After evaluating concordances and discordances of 4 existing CPGs, the authors performed a systematic literature search through February 2021. They screened articles for eligibility, assessed quality, and extracted and summarized the data from included articles. The authors formulated recommendations based on the evidence and clinical judgment. There were 3930 articles identified, and 83 of them, originating from 17 countries, were included. On a group level, survivors were more likely to have lower educational achievement and more likely to be unemployed than comparisons. Key risk factors for poor outcomes included receiving a primary diagnosis of a central nervous system tumor and experiencing late effects. The authors recommend that health care providers be aware of the risk of educational and employment problems, implement regular surveillance, and refer survivors to specialists if problems are identified. In conclusion, this review presents a harmonized CPG that aims to facilitate evidence-based care, positively influence education and employment outcomes, and ultimately minimize the burden of disease and treatment-related late adverse effects for survivors of CAYA cancers. LAY SUMMARY: A multidisciplinary panel has developed guidelines for the surveillance of education and employment outcomes among survivors of childhood, adolescent, and young adult cancer. On the basis of evidence showing that survivors are at risk for lower educational achievement and unemployment, it is recommended that all survivors receive regular screening for educational and employment outcomes

    TOI-2119: A transiting brown dwarf orbiting an active M-dwarf from NASA’s TESS mission

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    We report the discovery of TOI-2119b, a transiting brown dwarf (BD) that orbits and is completely eclipsed by an active M-dwarf star. Using light curve data from the Transiting Exoplanet Survey Satellite mission and follow-up high-resolution Doppler spectroscopic observations, we find the BD has a radius of Rb=1.08±0.03RJR_b = 1.08 \pm 0.03{\rm R_J}, a mass of Mb=64.4±2.3MJM_b = 64.4 \pm 2.3{\rm M_J}, an orbital period of P=7.200865±0.00002P = 7.200865 \pm 0.00002 days, and an eccentricity of e=0.337±0.002e=0.337\pm 0.002. The host star has a mass of M⋆=0.53±0.02M⊙M_\star = 0.53 \pm 0.02{\rm M_\odot}, a radius of R⋆=0.50±0.01R⊙R_\star= 0.50 \pm 0.01{\rm R_\odot}, an effective temperature of Teff=3621±48T_{\rm eff} = 3621 \pm 48K, and a metallicity of [Fe/H]=+0.06±0.08\rm [Fe/H]=+0.06\pm 0.08. TOI-2119b joins an emerging population of transiting BDs around M-dwarf host stars, with TOI-2119 being the ninth such system. These M-dwarf--brown dwarf systems typically occupy mass ratios near q=Mb/M⋆≈0.1−0.2q = M_b/M_\star \approx 0.1-0.2, which separates them from the typical mass ratios for systems with transiting substellar objects and giant exoplanets that orbit more massive stars. The nature of the secondary eclipse of the BD by the star enables us to estimate the effective temperature of the substellar object to be 2030±842030\pm 84K, which is consistent with predictions by substellar evolutionary models.Comment: 14 pages, 13 figures, 4 tables, accepted in MNRA

    Wnt5a Regulates Ventral Midbrain Morphogenesis and the Development of A9–A10 Dopaminergic Cells In Vivo

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    Wnt5a is a morphogen that activates the Wnt/planar cell polarity (PCP) pathway and serves multiple functions during development. PCP signaling controls the orientation of cells within an epithelial plane as well as convergent extension (CE) movements. Wnt5a was previously reported to promote differentiation of A9–10 dopaminergic (DA) precursors in vitro. However, the signaling mechanism in DA cells and the function of Wnt5a during midbrain development in vivo remains unclear. We hereby report that Wnt5a activated the GTPase Rac1 in DA cells and that Rac1 inhibitors blocked the Wnt5a-induced DA neuron differentiation of ventral midbrain (VM) precursor cultures, linking Wnt5a-induced differentiation with a known effector of Wnt/PCP signaling. In vivo, Wnt5a was expressed throughout the VM at embryonic day (E)9.5, and was restricted to the VM floor and basal plate by E11.5–E13.5. Analysis of Wnt5a−/− mice revealed a transient increase in progenitor proliferation at E11.5, and a precociously induced NR4A2+ (Nurr1) precursor pool at E12.5. The excess NR4A2+ precursors remained undifferentiated until E14.5, when a transient 25% increase in DA neurons was detected. Wnt5a−/− mice also displayed a defect in (mid)brain morphogenesis, including an impairment in midbrain elongation and a rounded ventricular cavity. Interestingly, these alterations affected mostly cells in the DA lineage. The ventral Sonic hedgehog-expressing domain was broadened and flattened, a typical CE phenotype, and the domains occupied by Ngn2+ DA progenitors, NR4A2+ DA precursors and TH+ DA neurons were rostrocaudally reduced and laterally expanded. In summary, we hereby describe a Wnt5a regulation of Wnt/PCP signaling in the DA lineage and provide evidence for multiple functions of Wnt5a in the VM in vivo, including the regulation of VM morphogenesis, DA progenitor cell division, and differentiation of NR4A2+ DA precursors
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