144 research outputs found

    The Path Forward: A Post-Omicron Strategy for the Global COVID-19 Response

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    At this pivotal moment, the world's response to the pandemic must shift from emergency crisis management to a sustainable control strategy. This strategy should help to build resilient health systems with capabilities to address potential future COVID-19 outbreaks and other public health threats. Driving the urgent need for an updated strategy are important recent developments related to the SARS-CoV-2 virus, the impact of current vaccines, and the world's response to the pandemic

    HST Grism-derived Forecasts for Future Galaxy Redshift Surveys

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    The mutually complementary Euclid and Roman galaxy redshift surveys will use Halpha- and [OIII]-selected emission line galaxies as tracers of the large scale structure at 0.9z1.90.9 \lesssim z \lesssim 1.9 (Halpha) and 1.5z2.71.5 \lesssim z \lesssim 2.7 ([OIII]). It is essential to have a reliable and sufficiently precise knowledge of the expected numbers of Halpha-emitting galaxies in the survey volume in order to optimize these redshift surveys for the study of dark energy. Additionally, these future samples of emission-line galaxies will, like all slitless spectroscopy surveys, be affected by a complex selection function that depends on galaxy size and luminosity, line equivalent width, and redshift errors arising from the misidentification of single emission-line galaxies. Focusing on the specifics of the Euclid survey, we combine two slitless spectroscopic WFC3-IR datasets -- 3D-HST+AGHAST and the WISP survey -- to construct a Euclid-like sample that covers an area of 0.56 deg2^2 and includes 1277 emission line galaxies. We detect 1091 (\sim3270 deg2^{-2}) Halpha+[NII]-emitting galaxies in the range 0.9z1.60.9\leq z \leq 1.6 and 162 (\sim440 deg2^{-2}) [OIII]λ\lambda5007-emitters over 1.5z2.31.5\leq z \leq 2.3 with line fluxes 2×1016\geq 2 \times 10^{-16} erg s1^{-1} cm2^{-2}. The median of the Halpha+[NII] equivalent width distribution is \sim250\r{A}, and the effective radii of the continuum and Halpha+[NII] emission are correlated with a median of \sim0.38" and significant scatter (σ\sigma \sim 0.2"-0.35"). Finally, we explore the prevalence of redshift misidentification in future Euclid samples, finding potential contamination rates of \sim14-20% and \sim6% down to 2×10162\times 10^{-16} and 6×10176 \times 10^{-17} erg s1^{-1} cm2^{-2}, respectively, though with increased wavelength coverage these percentages drop to nearly zero.Comment: Accepted for publication in ApJ. 27 pages, 17 figures, 3 table

    HST Grism-derived Forecasts for Future Galaxy Redshift Surveys

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    The mutually complementary Euclid and Roman galaxy redshift surveys will use Hα- and [O III]-selected emission-line galaxies (ELGs) as tracers of the large-scale structure at 0.9 ≾ z ≾ 1.9 (Hα) and 1.5 ≾ z ≾ 2.7 ([O III]). It is essential to have a reliable and sufficiently precise knowledge of the expected numbers of Hα-emitting galaxies in the survey volume in order to optimize these redshift surveys for the study of dark energy. Additionally, these future samples of ELGs will, like all slitless spectroscopy surveys, be affected by a complex selection function that depends on galaxy size and luminosity, line equivalent width (EW), and redshift errors arising from the misidentification of single ELGs. Focusing on the specifics of the Euclid survey, we combine two slitless spectroscopic WFC3-IR data sets—3D-HST+AGHAST and the WFC3 Infrared Spectroscopic Parallel survey—to construct a Euclid-like sample that covers an area of 0.56 deg² and includes 1277 ELGs. We detect 1091 (~3270 deg⁻²) Hα+[N II]-emitting galaxies in the range 0.9 ≤ z ≤ 1.6 and 162 (~440 deg⁻²) [O III] λ5007 emitters over 1.5 ≤ z ≤ 2.3 with line fluxes ≥2 × 10⁻¹⁶ erg s⁻¹ cm⁻². The median of the Hα+[N II] EW distribution is ~250 Å, and the effective radii of the continuum and Hα+[N II] emission are correlated with a median of ~0.”38 and significant scatter (σ ~ 0.”2–0.”35). Finally, we explore the prevalence of redshift misidentification in future Euclid samples, finding potential contamination rates of ~14%–20% and ~6% down to 2 × 10⁻¹⁶ erg s⁻¹ cm−2 and 6 × 10⁻¹⁷ erg s⁻¹ cm⁻², respectively, although with increased wavelength coverage these percentages drop to nearly zero

    Galaxy And Mass Assembly (GAMA) : the large-scale structure of galaxies and comparison to mock universes

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    MA acknowledges funding from the University of St Andrews and the International Centre for Radio Astronomy Research. ASGR is supported by funding from a UWA Fellowship. PN acknowledges the support of the Royal Society through the award of a University Research Fellowship and the European Research Council, through receipt of a Starting Grant (DEGAS-259586). MJIB acknowledges the financial support of the Australian Research Council Future Fellowship 100100280. TMR acknowledges support from a European Research Council Starting Grant (DEGAS-259586).From a volume-limited sample of 45 542 galaxies and 6000 groups with z ≤ 0.213, we use an adapted minimal spanning tree algorithm to identify and classify large-scale structures within the Galaxy And Mass Assembly (GAMA) survey. Using galaxy groups, we identify 643 filaments across the three equatorial GAMA fields that span up to 200 h−1 Mpc in length, each with an average of eight groups within them. By analysing galaxies not belonging to groups, we identify a secondary population of smaller coherent structures composed entirely of galaxies, dubbed ‘tendrils’ that appear to link filaments together, or penetrate into voids, generally measuring around 10 h−1 Mpc in length and containing on average six galaxies. Finally, we are also able to identify a population of isolated void galaxies. By running this algorithm on GAMA mock galaxy catalogues, we compare the characteristics of large-scale structure between observed and mock data, finding that mock filaments reproduce observed ones extremely well. This provides a probe of higher order distribution statistics not captured by the popularly used two-point correlation function.Peer reviewe

    Severe Acute Respiratory Syndrome Coronavirus 2 Reinfection: A Case Series From a 12-Month Longitudinal Occupational Cohort

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    Findings are described in 7 patients with severe acute respiratory syndrome coronavirus 2 reinfection from the National Basketball Association 2020-2021 occupational testing cohort, including clinical details, antibody test results, genomic sequencing, and longitudinal reverse-transcription polymerase chain reaction results. Reinfections were infrequent and varied in clinical presentation, viral dynamics, and immune response

    Para-infectious brain injury in COVID-19 persists at follow-up despite attenuated cytokine and autoantibody responses

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    To understand neurological complications of COVID-19 better both acutely and for recovery, we measured markers of brain injury, inflammatory mediators, and autoantibodies in 203 hospitalised participants; 111 with acute sera (1–11 days post-admission) and 92 convalescent sera (56 with COVID-19-associated neurological diagnoses). Here we show that compared to 60 uninfected controls, tTau, GFAP, NfL, and UCH-L1 are increased with COVID-19 infection at acute timepoints and NfL and GFAP are significantly higher in participants with neurological complications. Inflammatory mediators (IL-6, IL-12p40, HGF, M-CSF, CCL2, and IL-1RA) are associated with both altered consciousness and markers of brain injury. Autoantibodies are more common in COVID-19 than controls and some (including against MYL7, UCH-L1, and GRIN3B) are more frequent with altered consciousness. Additionally, convalescent participants with neurological complications show elevated GFAP and NfL, unrelated to attenuated systemic inflammatory mediators and to autoantibody responses. Overall, neurological complications of COVID-19 are associated with evidence of neuroglial injury in both acute and late disease and these correlate with dysregulated innate and adaptive immune responses acutely
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