13 research outputs found

    Genomic epidemiology of SARS-CoV-2 in a UK university identifies dynamics of transmission

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    AbstractUnderstanding SARS-CoV-2 transmission in higher education settings is important to limit spread between students, and into at-risk populations. In this study, we sequenced 482 SARS-CoV-2 isolates from the University of Cambridge from 5 October to 6 December 2020. We perform a detailed phylogenetic comparison with 972 isolates from the surrounding community, complemented with epidemiological and contact tracing data, to determine transmission dynamics. We observe limited viral introductions into the university; the majority of student cases were linked to a single genetic cluster, likely following social gatherings at a venue outside the university. We identify considerable onward transmission associated with student accommodation and courses; this was effectively contained using local infection control measures and following a national lockdown. Transmission clusters were largely segregated within the university or the community. Our study highlights key determinants of SARS-CoV-2 transmission and effective interventions in a higher education setting that will inform public health policy during pandemics.</jats:p

    Discovery of a Substellar Companion to the Nearby Debris Disk Host HR 2562

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    We present the discovery of a brown dwarf companion to the debris disk host star HR 2562. This object, discovered with the Gemini Planet Imager (GPI), has a projected separation of 20.3±0.3 au (0.618±0.004") from the star. With the high astrometric precision afforded by GPI, we have confirmed common proper motion of HR 2562B with the star with only a month time baseline between observations to more than 5σ. Spectral data in J, H, and K bands show morphological similarity to L/T transition objects. We assign a spectral type of L7±3 to HR 2562B, and derive a luminosity of log(Lbol/L⊙)=-4.62±0.12, corresponding to a mass of 30±15 MJup from evolutionary models at an estimated age of the system of 300-900 Myr. Although the uncertainty in the age of the host star is significant, the spectra and photometry exhibit several indications of youth for HR 2562B. The source has a position angle consistent with an orbit in the same plane as the debris disk recently resolved with Herschel. Additionally, it appears to be interior to the debris disk. Though the extent of the inner hole is currently too uncertain to place limits on the mass of HR 2562B, future observations of the disk with higher spatial resolution may be able to provide mass constraints. This is the first brown dwarf-mass object found to reside in the inner hole of a debris disk, offering the opportunity to search for evidence of formation above the deuterium burning limit in a circumstellar disk

    Dynamical Constraints on the HR 8799 Planets with GPI

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