Can inflationary models of cosmic perturbations evade the secondary oscillation test?

We consider the consequences of an observed Cosmic Microwave Background (CMB) temperature anisotropy spectrum containing no secondary oscillations. While such a spectrum is generally considered to be a robust signature of active structure formation, we show that such a spectrum {\em can} be produced by (very unusual) inflationary models or other passive evolution models. However, we show that for all these passive models the characteristic oscillations would show up in other observable spectra. Our work shows that when CMB polarization and matter power spectra are taken into account secondary oscillations are indeed a signature of even these very exotic passive models. We construct a measure of the observability of secondary oscillations in a given experiment, and show that even with foregrounds both the MAP and \pk satellites should be able to distinguish between models with and without oscillations. Thus we conclude that inflationary and other passive models can {\em not} evade the secondary oscillation test.Comment: Final version accepted for publication in PRD. Minor improvements have been made to the discussion and new data has been included. The conclusions are unchagne

Integrating sequence and array data to create an improved 1000 Genomes Project haplotype reference panel

A major use of the 1000 Genomes Project (1000GP) data is genotype imputation in genome-wide association studies (GWAS). Here we develop a method to estimate haplotypes from low-coverage sequencing data that can take advantage of single-nucleotide polymorphism (SNP) microarray genotypes on the same samples. First the SNP array data are phased to build a backbone (or 'scaffold') of haplotypes across each chromosome. We then phase the sequence data 'onto' this haplotype scaffold. This approach can take advantage of relatedness between sequenced and non-sequenced samples to improve accuracy. We use this method to create a new 1000GP haplotype reference set for use by the human genetic community. Using a set of validation genotypes at SNP and bi-allelic indels we show that these haplotypes have lower genotype discordance and improved imputation performance into downstream GWAS samples, especially at low-frequency variants. © 2014 Macmillan Publishers Limited. All rights reserved

Convalescent plasma in patients admitted to hospital with COVID-19 (RECOVERY): a randomised controlled, open-label, platform trial

Background: Many patients with COVID-19 have been treated with plasma containing anti-SARS-CoV-2 antibodies. We aimed to evaluate the safety and efficacy of convalescent plasma therapy in patients admitted to hospital with COVID-19. Methods: This randomised, controlled, open-label, platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]) is assessing several possible treatments in patients hospitalised with COVID-19 in the UK. The trial is underway at 177 NHS hospitals from across the UK. Eligible and consenting patients were randomly assigned (1:1) to receive either usual care alone (usual care group) or usual care plus high-titre convalescent plasma (convalescent plasma group). The primary outcome was 28-day mortality, analysed on an intention-to-treat basis. The trial is registered with ISRCTN, 50189673, and ClinicalTrials.gov, NCT04381936. Findings: Between May 28, 2020, and Jan 15, 2021, 11558 (71%) of 16287 patients enrolled in RECOVERY were eligible to receive convalescent plasma and were assigned to either the convalescent plasma group or the usual care group. There was no significant difference in 28-day mortality between the two groups: 1399 (24%) of 5795 patients in the convalescent plasma group and 1408 (24%) of 5763 patients in the usual care group died within 28 days (rate ratio 1·00, 95% CI 0·93–1·07; p=0·95). The 28-day mortality rate ratio was similar in all prespecified subgroups of patients, including in those patients without detectable SARS-CoV-2 antibodies at randomisation. Allocation to convalescent plasma had no significant effect on the proportion of patients discharged from hospital within 28 days (3832 [66%] patients in the convalescent plasma group vs 3822 [66%] patients in the usual care group; rate ratio 0·99, 95% CI 0·94–1·03; p=0·57). Among those not on invasive mechanical ventilation at randomisation, there was no significant difference in the proportion of patients meeting the composite endpoint of progression to invasive mechanical ventilation or death (1568 [29%] of 5493 patients in the convalescent plasma group vs 1568 [29%] of 5448 patients in the usual care group; rate ratio 0·99, 95% CI 0·93–1·05; p=0·79). Interpretation: In patients hospitalised with COVID-19, high-titre convalescent plasma did not improve survival or other prespecified clinical outcomes. Funding: UK Research and Innovation (Medical Research Council) and National Institute of Health Research

Systematic effects in microwave background observations

SIGLEAvailable from British Library Document Supply Centre- DSC:D061545 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Electromagnetic modelling of few-moded Winston cones in the far-infrared

Winston cones have traditionally been used as detector feeds in far-infrared cosmological experiments, such as SuZIe, the Sunyaev-Zel’dovich Infra-red Experiment [1] on the CSO. They are usually designed using ray tracing, which becomes a very poor approximation when the number of spatial modes propagated by the horn is small in number, often the case at the longest wavelengths. We describe a more accurate approach involving electromagnetic modelling of Winston cones using a rigorous electromagnetic mode matching technique. It is straightforward to also consider the case of few-moded corrugated Winston cones, which offer lower sidelobe levels than smooth walled cones which is important for high sensitivity experiments. Furthermore, the mode matching technique allows more complex structures such as back-to-back Winston cones and the detector cavities to also be analyzed

A Determination of the Hubble Constant Using Measurements of X-Ray Emission and the Sunyaev-Zeldovich Effect at Millimeter Wavelengths in the Cluster Abell 1835

We present a determination of the Hubble constant and central electron density in the cluster Abell 1835 (z = 0.2523) from measurements of X-ray emission and millimeter-wave observations of the Sunyaev-Zeldovich (S-Z) effect with the Sunyaev-Zeldovich Infrared Experiment (SuZIE) multifrequency array receiver. Abell 1835 is a well studied cluster in the X-ray with a large central cooling flow. Using a combination of data from ROSAT PSPC and HRI images and millimeter wave measurements we fit a King model to the emission from the ionized gas around Abell 1835 with θ0 = 022 ± 002 and β = 0.58 ± 0.02. Assuming the cluster gas to be isothermal with a temperature of 9.8 keV, we find a y-parameter of 4.9 ± 0.6 × 10-4 and a peculiar velocity of 500 ± 1000 km s-1 from measurements at three frequencies, 145, 221, and 279 GHz. Combining the S-Z measurements with X-ray data, we determine a value for the Hubble constant of H0 = 59 km s-1 Mpc-1 and a central electron density for Abell 1835 of ne0 = 5.64 × 10-2 cm-3 assuming a standard cosmology with Ωm = 1 and ΩΛ = 0. The error in the determination of the Hubble constant is dominated by the uncertainty in the temperature of the X-ray emitting cluster gas

Corrugated waveguide band edge filters for CMB experiments in the far infrared

Millimetre wave corrugated waveguide-horn structures are used as both single-moded and multi-moded bolometer feeds in a number of cosmic microwave background (CMB) experiments (e.g. PLANCK, Archeops, QUaD). Such horns tend to be employed over a relatively wide bandwidth and for single-moded horns the waveguide acts as the high pass filter. In this paper we report on our investigation on how the waveguide details determine the exact location of the low frequencyband edge of such corrugated horns. A sharp step-like band edge, below which there is negligible propagation, is ideallyrequired. Furthermore anyleakage below the expected cut-off, possible in corrugated guides, could lead to non-idealised cross-polar effects. Typically deeper corrugations are required in the waveguide filter than at the horn aperture for wide bandwidth operation, thus necessitating a transition section over which the corrugation depth smoothlyvaries. An electromagnetic mode matching technique and a surface impedance hybrid mode model are used to compute the horn transmission characteristics. We have also undertaken laboratorymeasurements of the band edge of prototype corrugated horns in order to test the models