Spectroscopic and Spectropolarimetric Observations of V838 Mon

The spectroscopic and spectropolarimetric variability of the peculiar variable V838 Monocerotis during the brighter phases of its multiple outbursts in 2002 is presented. Significant line profile variability of H$\alpha$ and Si II 6347.10\AA & 6371.36\AA occurred in spectra obtained between 2002 February 5 and 2002 March 14, and a unique secondary absorption component was observed near the end of this time period. Our observations also suggest that multiple shifts in ionization states occurred during the outbursts. Spectropolarimetric observations reveal that V838 Mon exhibited both intrinsic and interstellar polarization components during the initial stages of the second outburst, indicating the presence of an asymmetric geometry; however, the intrinsic component had significantly declined by February 14. We determine the interstellar polarization to be $P_{max} = 2.746 \pm 0.011$, $\lambda_{max} = 5790 \pm 37\AA$, $PA = 153.43 \pm 0.12 ^{\circ}$, and we find the integrated intrinsic V band polarization on February 5 to be $P = 0.983 \pm 0.012$ at a position angle of $127.0 \pm 0.5^{\circ}$. The implications of these observations for the nature of V838 Monocerotis, its distance, and its ejecta are discussed.Comment: 20 pages (including 6 figs, 3 tables), accepted by Ap

COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study

Background: The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms. Methods: International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results: ‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≤ 18 years: 69, 48, 23; 85%), older adults (≥ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P < 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation: This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men

The millimeter-wave bolometric interferometer (MBI)

We report on the design and tests of a prototype of the Millimeter-wave Bolometric Interferometer (MBI). MBIis designed to make sensitive measurements of the polarization of the cosmic microwave background (CMB). Itcombines the differencing capabilities of an interferometer with the high sensitivity of bolometers at millimeterwavelengths. The prototype, which we call MBI-4, views the sky directly through four corrugated horn antennas.MBI ultimately will have ~ 1000 antennas. These antennas have low sidelobes and nearly symmetric beampatterns, so spurious instrumental polarization from reflective optics is avoided. The MBI-4 optical band isdefined by filters with a central frequency of 90 GHz. The set of baselines, determined by placement of the fourantennas, results in sensitivity to CMB polarization fluctuations over the multipole range ℓ = 150 - 270. Thesignals are combined with a Fizeau beam combiner and interference fringes are detected by an array of spider-webbolometers. In order to separate the visibility signals from the total power detected by each bolometer, thephase of the signal from each antenna is modulated by a ferrite-based waveguide phase shifter. Initial tests andobservations have been made at Pine Bluff Observatory (PBO) outside Madison, WI

The Millimeter-wave Bolometric Interferometer (MBI)

We report on the design and tests of a prototype of the Millimeter-wave Bolometric Interferometer (MBI). MBI is designed to make sensitive measurements of the polarization of the cosmic microwave background (CMB). It combines the differencing capabilities of an interferometer with the high sensitivity of bolometers at millimeter wavelengths. The prototype, which we call MBI-4, views the sky directly through four corrugated horn antennas. MBI ultimately will have 1000 antennas. These antennas have low sidelobes and nearly symmetric beam patterns, so spurious instrumental polarization from reflective optics is avoided. The MBI-4 optical band is defined by filters with a central frequency of 90 GHz. The set of baselines, determined by placement of the four antennas, results in sensitivity to CMB polarization fluctuations over the multipole range l = 150 - 270. The signals are combined with a Fizeau beam combiner and interference fringes are detected by an array of spiderweb bolometers. In order to separate the visibility signals from the total power detected by each bolometer, the phase of the signal from each antenna is modulated by a ferrite-based waveguide phase shifter. Initial tests and observations have been made at Pine Bluff Observatory (PBO) outside Madison, WI