The Milky Way bar/bulge in proper motions: a 3D view from VIRAC & Gaia

© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society.We have derived absolute proper motions of the entire Galactic bulge region from VIRAC and Gaia. We present these as both integrated on-sky maps and, after isolating standard candle red clump (RC) stars, as a function of distance using RC magnitude as a proxy. These data provide a new global, 3-dimensional view of the Milky Way barred bulge kinematics. We find a gradient in the mean longitudinal proper motion, $\mu_l$, between the different sides of the bar, which is sensitive to the bar pattern speed. The split RC has distinct proper motions and is colder than other stars at similar distance. The proper motion correlation map has a quadrupole pattern in all magnitude slices showing no evidence for a separate, more axisymmetric inner bulge component. The line-of-sight integrated kinematic maps show a high central velocity dispersion surrounded by a more asymmetric dispersion profile. $\sigma_{\mu_l} / \sigma_{\mu_b}$ is smallest, $\sim1.1$, near the minor axis and reaches $\sim1.4$ near the disc plane. The integrated $$ pattern signals a superposition of bar rotation and internal streaming motion, with the near part shrinking in latitude and the far part expanding. To understand and interpret these remarkable data, we compare to a made-to-measure barred dynamical model, folding in the VIRAC selection function to construct mock maps. We find that our model of the barred bulge, with a pattern speed of 37.5 $\mathrm{km \, s^{-1} \, kpc^{-1}}$, is able to reproduce all observed features impressively well. Dynamical models like this will be key to unlocking the full potential of these data.Peer reviewe

Optic cup and facial patterning defects in ocular ectoderm β-catenin gain-of-function mice

BACKGROUND: The canonical Wnt signaling pathway has a number of critical functions during embryonic development and, when activated aberrantly, in the genesis of cancer. Current evidence suggests that during eye development, regulation of Wnt signaling is critical for patterning the surface ectoderm that will contribute to multiple components of the eye. Wnt signaling loss-of-function experiments show that a region of periocular ectoderm will form ectopic lentoid bodies unless the Wnt pathway modifies its fate towards other structures. Consistent with this, Wnt signaling gain of function in the ocular region ectoderm results in a suppression of lens fate. RESULTS: Here we demonstrate that ectoderm-specific Wnt signaling gain-of-function embryos exhibit additional defects besides those noted in the lens. There are profound facial defects including a foreshortened snout, malformation of the nasal region, and clefting of the epidermis along the ocular-nasal axis. Furthermore, despite the restriction of Wnt pathway gain-of-function to the surface ectoderm, the optic cup is inappropriately patterned and ultimately forms a highly convoluted, disorganized array of epithelium with the characteristics of retina and retinal pigmented epithelium. CONCLUSION: We suggest that activation of the Wnt pathway in surface ectoderm may disrupt the normal exchange of signals between the presumptive lens and retina that coordinate development of a functional eye

Introducing open book examinations in clinical education: A case study

During the recent COVID-19 pandemic, in common with educators across the Higher Education sector, the School of Dentistry at the University of Liverpool reimagined the learning and assessment strategy by moving from proctored closed-book assessment to largely unmonitored open-book examinations (OBE). This article discusses understandings from an educator perspective following our implementation of OBE. The educator perspective discussed here indicates that OBE have the potential to be an authentic and acceptable form of assessment, but that some reframing of attitudes towards assessment from all stakeholders and their approaches to assessment is necessary when developing these innovative types of assessment

A deep WISE search for very late type objects and the discovery of two halo/thick-disc T dwarfs : WISE 0013+0634 and WISE 0833+0052

This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2013 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reservedA method is defined for identifying late-T and Y dwarfs in WISE down to low values of signal-to-noise. This requires a WISE detection only in the W2-band and uses the statistical properties of the WISE multiframe measurements and profile fit photometry to reject contamination resulting from non-point-like objects, variables and moving sources. To trace our desired parameter space, we use a control sample of isolated non-moving non-variable point sources from the Sloan Digital Sky Survey (SDSS), and identify a sample of 158 WISE W2-only candidates down to a signal-to-noise limit of eight. For signal-to-noise ranges >10 and 8-10, respectively, similar to 45 and similar to 90 per cent of our sample fall outside the selection criteria published by the WISE team, mainly due to the type of constraints placed on the number of individual W2 detections. We present follow-up of eight candidates and identify WISE 0013+0634 and WISE 0833+0052, T8 and T9 dwarfs with high proper motion (similar to 1.3 and similar to 1.8 arcsec yr(-1)). Both objects show a mid-infrared/near-infrared excess of similar to 1-1.5 mag and are K band suppressed. Distance estimates lead to space motion constraints that suggest halo (or at least thick disc) kinematics. We then assess the reduced proper motion diagram of WISE ultracool dwarfs, which suggests that late-T and Y dwarfs may have a higher thick-disc/halo population fraction than earlier objects.Peer reviewe

Zn3As2 Nanowires and nanoplatelets: highly efficient infrared emission and photodetection by an earth abundant material

The development of earth abundant materials for optoelectronics and photovoltaics promises improvements in sustainability and scalability. Recent studies have further demonstrated enhanced material efficiency through the superior light management of novel nanoscale geometries such as the nanowire. Here we show that an industry standard epitaxy technique can be used to fabricate high quality II-V nanowires (1D) and nanoplatelets (2D) of the earth abundant semiconductor Zn3As2. We go on to establish the optoelectronic potential of this material by demonstrating efficient photoemission and detection at 1.0 eV, an energy which is significant to the fields of both photovoltaics and optical telecommunications. Through dynamical spectroscopy this superior performance is found to arise from a low rate of surface recombination combined with a high rate of radiative recombination. These results introduce nanostructured Zn3As2 as a high quality optoelectronic material ready for device exploration.T.B., P.C., Y.G., H.H.T., and C.J. acknowledge the Australian Research Council. T.B., P.C., Y.G., H.H.T., and C.J. thank the Australian National Fabrication Facility for access to the growth and microscopy facilities and Centre for Advanced Microscopy and Australian Microscopy and Microanalysis Research Facility for access to microscopy facilities used in this work. Y.W., B.B., H.E.J., and L.M.S. acknowledge the financial support of the National Science Foundation through grants DMR-1105362, 1105121, and ECCS-1100489

A recurrent missense variant in HARS2 results in variable sensorineural hearing loss in three unrelated families

HARS2 encodes mitochondrial histidyl-tRNA synthetase (HARS2), which links histidine to its cognate tRNA in the mitochondrial matrix. Biallelic variants in HARS2 are associated with Perrault syndrome, a rare recessive condition characterized by sensorineural hearing loss in both sexes and primary ovarian insufficiency in 46,XX females. Some individuals with Perrault syndrome have a broader phenotypic spectrum with neurological features, including ataxia and peripheral neuropathy. Here, we report a recurrent variant in HARS2 in association with sensorineural hearing loss. In affected individuals from three unrelated families, the variant HARS2 c.1439G>A p.(Arg480His) is present as a heterozygous variant in trans to a putative pathogenic variant. The low prevalence of the allele HARS2 c.1439G>A p.(Arg480His) in the general population and its presence in three families with hearing loss, confirm the pathogenicity of this variant and illustrate the presentation of Perrault syndrome as nonsyndromic hearing loss in males and prepubertal females

Balance assessment in Multiple Sclerosis and cerebellar ataxia: rationale, protocol and demographic data

A core set of standardized balance measures are required for use in rehabilitation among people with multiple sclerosis (MS) and cerebellar ataxia. An earlier systematic review and Delphi survey identified the Berg Balance Scale (BBS), the Timed Up and Go test (TUG), Posture and Gait sub-component of the International Co-operative Ataxia Rating Scale (PG of ICARS) and the gait, sitting and stance sub-components of the Scale for the Assessment and Rating of Ataxia (SARA Bal) as suitable balance measures. This study aims to estimate the reliability, validity and interpretability of these measures. This study will recruit 60 participants with multiple sclerosis with secondary cerebellar involvement across four centres in New Zealand and the United States of America. Participants will be assessed and videotaped performing the BBS, TUG, SARA Bal and PG of ICARS by trained physiotherapists. Barthel Index, Expanded Disability Status Scale (EDSS), Disease duration, ICARS and SARA will also be assessed to determine validity. A second assessment to determine reliability will be conducted by assessors watching the video-recording. Data collection is in progress, 44 samples have been collected and the demographic data are presented. The findings of this study will recommend a core set of reliable, valid and interpretable measures that are suitable for clinical practice and research for the assessment of balance among adults with MS and cerebellar ataxia. Minimal Clinically Important Difference (MCID) and cut-off scores to predict the use of assistive walking device will be established

NPARSEC : NTT Parallaxes of Southern Extremely Cool objects. Goals, targets, procedures and first results

The discovery and subsequent detailed study of T dwarfs have provided many surprises and pushed the physics and modelling of cool atmospheres in unpredicted directions. Distance is a critical parameter for studies of these objects to determine intrinsic luminosities, test binarity and measure their motion in the Galaxy. We describe a new observational programme to determine distances across the full range of T-dwarf subtypes using the New Technology Telescope (NTT)/SOFI telescope/instrument combination. We present preliminary results for ten objects, five of which represent new distances.Peer reviewe