697 research outputs found
Directionality in the Wilkinson Microwave Anisotropy Probe Polarization Data
No full textPolarization is the next frontier of cosmic microwave background analysis, but its signal is dominated over much of the sky by foregrounds which must be carefully removed. To determine the efficacy of this cleaning, it is necessary to have sensitive tests for residual foreground contamination in polarization sky maps. The dominant Galactic foregrounds introduce a large-scale anisotropy on to the sky, so it makes sense to use a statistic sensitive to overall directionality for this purpose. Here, we adapt the rapidly computable D statistic of Bunn and Scott to polarization data, and demonstrate its utility as a foreground monitor by applying it to the low resolution Wilkinson Microwave Anisotropy Probe 3-yr sky maps. With a thorough simulation of the maps’ noise properties, we find no evidence for contamination in the foreground cleaned sky maps
Efficient Decomposition of Cosmic Microwave Background Polarization Maps into Pure E, Pure B, and Ambiguous Components.
No full textSeparation of the B component of a cosmic microwave background (CMB) polarization map from the much larger E component is an essential step in CMB polarimetry. For a map with incomplete sky coverage, this separation is necessarily hampered by the presence of ambiguous modes which could be either E or B modes. I present an efficient pixel-space algorithm for removing the ambiguous modes and separating the map into pure E and B components. The method, which works for arbitrary geometries, does not involve generating a complete basis of such modes and scales the cube of the number of pixels on the boundary of the map
Data from: Metabolomics - Emory Cardiovascular Biobank
No full textUntargeted high-resolution plasma metabolomic profiling among patients with coronary artery disease. Patients recruited from the Emory Cardiovascular Biobank into independent discovery and validation cohorts.This DATSETNAMEreadme.txt file was generated on 2020-08-20 by ANURAG MEHTA and CHANG LIU
GENERAL INFORMATION
1. Title of Dataset: Emory Cardiovascular Biobank Metabolomics
2. Author Information
A. Principal Investigator Contact Information
Name: Arshed A. Quyyumi, MD
Institution: Emory University School of Medicine
Address: 1462 Clifton Road NE, Suite 507, Atlanta, Georgia 30329
Email: [email protected]
B. Associate or Co-investigator Contact Information
Name: Anurag Mehta, MD
Institution: Emory University School of Medicine
Address: 1462 Clifton Road NE, Suite 513, Atlanta, Georgia 30329
Email: [email protected]
C. Alternate Contact Information
Name: Chang Liu
Institution: Emory University School of Medicine
Address: 1462 Clifton Road NE, Atlanta, Georgia 30329
Email: [email protected]
3. Date of data collection: 2004 to 2016
4. Information about funding sources that supported the collection of the data: National Heart, Lung, and Blood Institute grant 1P20HL113451
SHARING/ACCESS INFORMATION
1. Links to publications that cite or use the data: https://doi.org/10.1371/journal.pone.0237579
2. Links to other publicly accessible locations of the data: https://doi.org/10.5061/dryad.866t1g1mt
3. Links/relationships to ancillary data sets: none
4. Was data derived from another source? no
5. Recommended citation for this dataset: Mehta A, Liu C, Quyyumi AA. Emory Cardiovascular Biobank Metabolomics. 2020
DATA & FILE OVERVIEW
1. File List: Analysis_data_first_cohort.csv; Analysis_data_second_cohort.csv
2. Relationship between files: data of two separate cohorts
3. Additional related data collected that was not included in the current data package: none
4. Are there multiple versions of the dataset? no
METHODOLOGICAL INFORMATION: please see description in materials and methods section of the manuscript
DATA-SPECIFIC INFORMATION FOR: Analysis_data_first_cohort.csv
1. Number of variables: 6796
2. Number of cases/rows: 454
3. Variable List:
GENEID: subject IDs
timetodeath3yr: time to death event or censoring at three years
death3yr: death event at three years
age: age in years
male: male gender, 1=male, 0=female
BlackRace: black race, 1=black, 0=non-black
batch: batch of metabolomics profiling
Strokehx: history of stroke, 1=yes, 0=no
CABGhx: prior CABG, 1=yes, 0=no
PVDhx: peripheral artery disease, 1=yes, 0=no
eGFR_max120_lt60: estimated glomerular filtration rate less than 60 ml/min/1.73m2, 1=yes, 0=no
curr_smoking: current smoking, 1=yes, 0=no
HFhx: heart failure history, 1=yes, 0=no
HTN: hypertension, 1=yes, 0=no
DM: diabetes, 1=yes, 0=no
mzXX_tXX: intensities of metabolic features
4. Missing data codes: NA
DATA-SPECIFIC INFORMATION FOR: Analysis_data_second_cohort.csv
1. Number of variables: 8729
2. Number of cases/rows: 322
3. Variable List:
GENEID: subject IDs
timetodeath3yr: time to death event or censoring at three years
death3yr: death event at three years, 1=yes, 0=no
age: age in years
male: male gender, 1=male, 0=female
BlackRace: black race, 1=black, 0=non-black
batch: batch of metabolomics profiling
Strokehx: history of stroke, 1=yes, 0=no
CABGhx: prior CABG, 1=yes, 0=no
PVDhx: peripheral artery disease, 1=yes, 0=no
eGFR_max120_lt60: estimated glomerular filtration rate less than 60 ml/min/1.73m2, 1=yes, 0=no
curr_smoking: current smoking, 1=yes, 0=no
HFhx: heart failure history, 1=yes, 0=no
HTN: hypertension, 1=yes, 0=no
DM: diabetes, 1=yes, 0=no
mzXX_tXX: intensities of metabolic features
4. Missing data codes: NA
Funding provided by: National Heart, Lung, and Blood InstituteCrossref Funder Registry ID: http://dx.doi.org/10.13039/100000050Award Number: 1P20HL113451Funding provided by: American Heart AssociationCrossref Funder Registry ID: http://dx.doi.org/10.13039/100000968Award Number: 19POST34400057Dataset collected as part of Emory Cardiovascular Biobank - a prospective regsitry of patients with coronary artery diseas
Testing for Directionality in the Planck Polarization and Lensing Data
No full textIn order to better analyse the polarization of the cosmic microwave background (CMB), which is dominated by emission from our Galaxy, we need tools that can detect residual foregrounds in cleaned CMB maps. Galactic foregrounds introduce statistical anisotropy and directionality to the polarization pseudo-vectors of the CMB, which can be investigated by using the D statistic of Bunn and Scott. This statistic is rapidly computable and capable of investigating a broad range of data products for directionality. We demonstrate the application of this statistic to detecting foregrounds in polarization maps by analysing the uncleaned Planck 2018 frequency maps. For the Planck 2018 CMB maps, we find no evidence for residual foreground contamination; however, we detect an excess directionality due to anisotropic noise, which can be dealt with through careful simulations. In order to examine the sensitivity of the D statistic, we add a varying fraction of the polarized thermal dust and synchrotron foreground maps to the CMB maps and show that roughly per-cent-level foreground contamination would be detected with 95 per cent confidence. We also demonstrate application of the D statistic to another data product by analysing the gradient of the minimum-variance CMB lensing potential map (i.e., the deflection angle) for directionality. We find no excess directionality in the lensing potential map when compared to the simulations provided by the Planck Collaboration
Aestheticizing a Political Debate: Can the Creek Confederacy Be Sung Back Together?
No full textSpeaking at Emory University on April 13, 2007, Dr. Womack explores the complex historical relationship between African Americans and the Creek Confederacy through a close reading of two short stories by Creek author Alexander Posey: "Uncle Dick and Uncle Will" (1894) and "Uncle Dick's Sow" (1900)
Pure E and B polarization maps via Wiener filtering
No full textInternational audienceIn order to draw scientific conclusions from observations of cosmic microwave background (CMB) polarization, it is necessary to separate the contributions of the E and B components of the data. For data with incomplete sky coverage, there are ambiguous modes, which can be sourced by either E or B signals. Techniques exist for producing “pure” E and B maps, which are guaranteed to be free of cross-contamination, although the standard method, which involves constructing an eigenbasis, has a high computational cost. We show that such pure maps can be thought of as resulting from the application of a Wiener filter to the data. This perspective leads to far more efficient methods of producing pure maps. Moreover, by expressing the idea of purification in the general framework of Wiener filtering (i.e., maximization of a posterior probability), it leads to a variety of generalizations of the notion of pure E and B maps, e.g., accounting for noise or other contaminants in the data as well as correlations with temperature anisotropy
Cosmic Microwave Background Constraints on Cosmological Models with Large-Scale Isotropy Breaking
No full textSeveral anomalies appear to be present in the large-angle cosmic microwave background anisotropy maps of the Wilkinson Microwave Anisotropy Probe, including the alignment of large-scale multipoles. Models in which isotropy is spontaneously broken (e.g., by a scalar field) have been proposed as explanations for these anomalies, as have models in which a preferred direction is imposed during inflation. We examine models inspired by these, in which isotropy is broken by a multiplicative factor with dipole and/or quadrupole terms. We evaluate the evidence provided by the multipole alignment using a Bayesian framework, finding that the evidence in favor of the model is generally weak. We also compute approximate changes in estimated cosmological parameters in the broken-isotropy models. Only the overall normalization of the power spectrum is modified significantly
Systematic Errors in Cosmic Microwave Background Interferometry
No full textCosmic microwave background (CMB) polarization observations will require superb control of systematic errors in order to achieve their full scientific potential, particularly in the case of attempts to detect the B modes that may provide a window on inflation. Interferometry may be a promising way to achieve these goals. This paper presents a formalism for characterizing the effects of a variety of systematic errors on interferometric CMB polarization observations, with particular emphasis on estimates of the B-mode power spectrum. The most severe errors are those that couple the temperature anisotropy signal to polarization; such errors include cross talk within detectors, misalignment of polarizers, and cross polarization. In a B mode experiment, the next most serious category of errors are those that mix E and B modes, such as gain fluctuations, pointing errors, and beam shape errors. The paper also indicates which sources of error may cause circular polarization (e.g., from foregrounds) to contaminate the cosmologically interesting linear polarization channels, and conversely whether monitoring of the circular-polarization channels may yield useful information about the errors themselves. For all the sources of error considered, estimates of the level of control that will be required for both E and B mode experiments are provided. Simulations of a mock experiment are presented to illustrate the results. Both experiments that interfere linear polarizations and those that interfere circular polarizations are considered. The fact that circular experiments simultaneously measure both linear polarization Stokes parameters in each baseline mitigates some sources of error
- …
