Abstract
We report an improved measurement of the degree-scale cosmic microwave background
B
-mode angular-power spectrum over 670 deg
2
sky area at 150 GHz with P
olarbear
. In the original analysis ...of the data, errors in the angle measurement of the continuously rotating half-wave plate, a polarization modulator, caused significant data loss. By introducing an angle-correction algorithm, the data volume is increased by a factor of 1.8. We report a new analysis using the larger data set. We find the measured
B
-mode spectrum is consistent with the ΛCDM model with Galactic dust foregrounds. We estimate the contamination of the foreground by cross-correlating our data and Planck 143, 217, and 353 GHz measurements, where its spectrum is modeled as a power law in angular scale and a modified blackbody in frequency. We place an upper limit on the tensor-to-scalar ratio
r
< 0.33 at 95% confidence level after marginalizing over the foreground parameters.
Using only cosmic microwave background polarization data from the polarbear experiment, we measure B-mode polarization delensing on subdegree scales at more than 5σ significance. We achieve a 14% ...B-mode power variance reduction, the highest to date for internal delensing, and improve this result to 22% by applying for the first time an iterative maximum a posteriori delensing method. Our analysis demonstrates the capability of internal delensing as a means of improving constraints on inflationary models, paving the way for the optimal analysis of next-generation primordial B-mode experiments.
We report a measurement of the E-mode polarization power spectrum of the cosmic microwave background (CMB) using 150 GHz data taken from 2014 July to 2016 December with the Polarbear experiment. We ...reach an effective polarization map noise level of - across an observation area of 670 square degrees. We measure the EE power spectrum over the angular multipole range , tracing the third to seventh acoustic peaks with high sensitivity. The statistical uncertainty on E-mode bandpowers is ∼2.3 at , with a systematic uncertainty of 0.5 . The data are consistent with the standard ΛCDM cosmological model with a probability-to-exceed of 0.38. We combine recent CMB E-mode measurements and make inferences about cosmological parameters in ΛCDM as well as in extensions to ΛCDM. Adding the ground-based CMB polarization measurements to the Planck data set reduces the uncertainty on the Hubble constant by a factor of 1.2 to . When allowing the number of relativistic species ( ) to vary, we find , which is in good agreement with the standard value of 3.046. Instead allowing the primordial helium abundance ( ) to vary, the data favor . This is very close to the expectation of 0.2467 from big bang nucleosynthesis. When varying both and , we find and .
We present a measurement of the B-mode polarization power spectrum of the cosmic microwave background (CMB) using data taken from 2014 July to 2016 December with the Polarbear experiment. The CMB ...power spectra are measured using observations at 150 GHz with an instantaneous array sensitivity of on a 670 square degree patch of sky centered at (R.A., decl.) = (+0h12m0s, −59°18′). A continuously rotating half-wave plate is used to modulate polarization and to suppress low-frequency noise. We achieve 32 K arcmin effective polarization map noise with a knee in sensitivity of = 90, where the inflationary gravitational-wave signal is expected to peak. The measured B-mode power spectrum is consistent with a ΛCDM lensing and single dust component foreground model over a range of multipoles 50 ≤ ≤ 600. The data disfavor zero at 2.2 using this range of Polarbear data alone. We cross-correlate our data with Planck full mission 143, 217, and 353 GHz frequency maps and find the low- B-mode power in the combined data set to be consistent with thermal dust emission. We place an upper limit on the tensor-to-scalar ratio r < 0.90 at the 95% confidence level after marginalizing over foregrounds.
We present a measurement of the gravitational lensing deflection power spectrum reconstructed with two seasons of cosmic microwave background polarization data from the Polarbear experiment. ...Observations were taken at 150 GHz from 2012 to 2014 and surveyed three patches of sky totaling 30 square degrees. We test the consistency of the lensing spectrum with a cold dark matter cosmology and reject the no-lensing hypothesis at a confidence of 10.9 , including statistical and systematic uncertainties. We observe a value of AL = 1.33 0.32 (statistical) 0.02 (systematic) 0.07 (foreground) using all polarization lensing estimators, which corresponds to a 24% accurate measurement of the lensing amplitude. Compared to the analysis of the first-year data, we have improved the breadth of both the suite of null tests and the error terms included in the estimation of systematic contamination.
The polarization of the atmosphere has been a long-standing concern for ground-based experiments targeting cosmic microwave background (CMB) polarization. Ice crystals in upper tropospheric clouds ...scatter thermal radiation from the ground and produce a horizontally polarized signal. We report a detailed analysis of the cloud signal using a ground-based CMB experiment, Polarbear, located at the Atacama desert in Chile and observing at 150 GHz. We observe horizontally polarized temporal increases of low-frequency fluctuations ("polarized bursts," hereafter) of 0.1 K when clouds appear in a webcam monitoring the telescope and the sky. The hypothesis of no correlation between polarized bursts and clouds is rejected with >24 statistical significance using three years of data. We consider many other possibilities including instrumental and environmental effects, and find no reasons other than clouds that can explain the data better. We also discuss the impact of the cloud polarization on future ground-based CMB polarization experiments.
We report a 4.8 measurement of the cross-correlation signal between the cosmic microwave background (CMB) lensing convergence reconstructed from measurements of the CMB polarization made by the ...Polarbear experiment and the infrared-selected galaxies of the Herschel-ATLAS survey. This is the first measurement of its kind. We infer a best-fit galaxy bias of , corresponding to a host halo mass of at an effective redshift of z ∼ 2 from the cross-correlation power spectrum. Residual uncertainties in the redshift distribution of the submillimeter galaxies are subdominant with respect to the statistical precision. We perform a suite of systematic tests, finding that instrumental and astrophysical contaminations are small compared to the statistical error. This cross-correlation measurement only relies on CMB polarization information that, differently from CMB temperature maps, is less contaminated by galactic and extragalactic foregrounds, providing a clearer view of the projected matter distribution. This result demonstrates the feasibility and robustness of this approach for future high-sensitivity CMB polarization experiments.
POLARBEAR-2b (PB-2b) is the second of three cryogenic receivers of the Simons Array cosmic microwave background polarization experiment. PB-2b contains over 7500 transition-edge sensor (TES) ...bolometers cooled to 250 mK and read out using digital frequency-division multiplexing (DfMux). Stray impedance in the DfMux circuit obscures TES characterization and affects TES dynamic behavior. In order to accurately characterize TESs, it is necessary to account for stray impedance in the bias circuit. We define a stray impedance model, and we describe the technique used to measure model parameters in situ and to remove their effects on TES characterization. We use the same model to predict TES dynamic behavior and show good agreement between data and the model.
Deployment of Polarbear-2A Kaneko, Daisuke; Adachi, S.; Ade, P. A. R. ...
Journal of low temperature physics,
05/2020, Letnik:
199, Številka:
3-4
Journal Article
Recenzirano
Odprti dostop
Polarbear
-2A is the first of three receivers in the Simons array, a cosmic microwave background experiment located on the Atacama Plateau in Chile.
Polarbear
-2A was deployed and achieved the first ...light in January 2019 by mapping the microwave emission from planet observations. Commissioning work is underway to prepare the receiver for science observations.
Abstract
Background
Frailty is common amongst older patients with myocardial infarction and is an independent predictor of poor clinical outcomes. Despite this, frailty is not systematically or ...objectively measured nor routinely used in risk stratification. The electronic Frailty Index (eFI) is a frailty assessment tool which uses electronic health records to identify and classify frailty and has been shown to correlate well with in-person frailty assessment. However, the performance of the eFI in disease specific populations and its ability to predict individual patient outcomes is unclear.
Purpose
To assess the relationship between frailty, measured using the eFI, and the management and outcomes of older patients with myocardial infarction.
Methods
Consecutive patients admitted to hospital in the South East of Scotland between 01/10/2014 and the 01/03/2021 with a primary diagnosis of myocardial infarction were identified using International Classification of Disease (ICD-10) code I21 or I22. Patients under the age of 65 (n= 3,601) and those with no biomarker evidence of myocardial injury were excluded (n=1,301). The provision of guideline recommended therapy, recurrent hospital admission due to myocardial infarction, heart failure or stroke and 12-month all-cause mortality were compared between groups based on eFI classification (fit, mild, moderate or severely frail).
Results
Of the 3,930 patients (mean age 78 SD 8 years, 43% female, 83% Caucasian), 2,324 (59%) were classified as frail with 1,421 (36%), 664 (17%), and 239 (6%) classified as mild, moderate and severely frail, respectively. The eFI was measurable in all patients. Patients with any degree of frailty were less likely to receive anti-platelet therapy, ACE inhibitor or angiotensin receptor blocker or beta-blocker therapy or undergo revascularisation with fewer than 1 in 10 patients with severe frailty undergoing inpatient coronary catheterisation (7.5% vs 57% non-frail, P <0.001 for all). Frailty was independently associated with an increased incidence of recurrent myocardial infarction, heart failure or stroke within 12 months with the odds greatest in those with severe frailty (OR 1.93 (95% CI 1.42-2.61%)). The primary outcome of all-cause death at 12-months occurred in 355 (25%), 226 (34%) and 109 (46%) patients with mild, moderate and severe frailty compared with 176 (11%) in non-frail patients (Figure 1). Frailty status was an independent risk factor for all-cause mortality with the risk of death greatest in those with severe frailty (HR 2.64 (95% CI 1.63 – 3.67, p<0.001)).
Conclusion
The eFI identified patients at increased risk of in-patient death, major adverse cardiovascular events, and all-cause mortality within 12 months following myocardial infarction. Measurement of the eFI from linked healthcare data is feasible and could be used to aide personalised risk stratification and service utilisation in older patients admitted with myocardial infarction.Cumulative incidence plotForest plot with adjusted hazard ratio