138 research outputs found
Characterizing and Quantifying Time Dependent Night Sky Brightness in and around Tucson, Arizona
As part of a Research Experience for Undergraduates (REU) program with the National Optical Astronomy Observatory (NOAO), I (with mentor Dr. Constance Walker of NOAO) characterized light pollution in and near Tucson, Arizona using eight Sky Quality Meters (SQMs). In order to analyze the data in a consistent way for comparison, we created a standard procedure for reduction and analysis using python and MATLAB. The series of python scripts remove faulty data and examine specifically anthropogenic light pollution by excluding contributions made by the sun, moon, and the Milky Way. We then use MATLAB codes to illustrate how the light pollution changes in relation to time, distance from the city, and airglow. Data are then analyzed by a recently developed sky brightness model created by Dan Duriscoe of the National Park Service. To quantify the measurements taken by SQMs, we tested the wavelength sensitivity of the devices used for the data collection. The findings from the laboratory testing have prompted innovations for the SQMs as well as given a sense of how data gathered by these devices should be treated
TRALI: Party of One; Real-Time Hemovigilance Demonstrates Multiple Event-Free Transfusions
Mechele Adrian pictured.https://openworks.mdanderson.org/aprn-week-23/1019/thumbnail.jp
Citizen Science Provides Valuable Data for Monitoring Global Night Sky Luminance
The skyglow produced by artificial lights at night is one of the most dramatic
anthropogenic modifications of Earth’s biosphere. The GLOBE at Night citizen
science project allows individual observers to quantify skyglow using star
maps showing different levels of light pollution. We show that aggregated
GLOBE at Night data depend strongly on artificial skyglow, and could be used
to track lighting changes worldwide. Naked eye time series can be expected to
be very stable, due to the slow pace of human eye evolution. The standard
deviation of an individual GLOBE at Night observation is found to be 1.2
stellar magnitudes. Zenith skyglow estimates from the ‘‘First World Atlas of
Artificial Night Sky Brightness’’ are tested using a subset of the GLOBE at
Night data. Although we find the World Atlas overestimates sky brightness in
the very center of large cities, its predictions for Milky Way visibility are
accurate
N-oleoyldopamine, a novel endogenous capsaicin-like lipid that produces hyperalgesia.
N-Arachidonoyldopamine (NADA) was recently identified as an endogenous ligand for the vanilloid type 1 receptor (VR1). Further analysis of the bovine striatal extract from which NADA was isolated indicated the existence of substances corresponding in molecular mass to N-oleoyldopamine (OLDA), N-palmitoyldopamine (PALDA), and N-stearoyldopamine (STEARDA). Quadrupole time-of-flight mass spectrometric analysis of bovine striatal extracts revealed the existence of OLDA, PALDA, and STEARDA as endogenous compounds in the mammalian brain. PALDA and STEARDA failed to affect calcium influx in VR1-transfected human embryonic kidney (HEK) 293 cells or paw withdrawal latencies from a radiant heat source, and there was no evidence of spontaneous pain behavior. By contrast, OLDA induced calcium influx (EC(50) = 36 nm), reduced the latency of paw withdrawal from a radiant heat source in a dose-dependent manner (EC(50) = 0.72 microg), and produced nocifensive behavior. These effects were blocked by co-administration of the VR1 antagonist iodo-resiniferatoxin (10 nm for HEK cells and 1 microg/50 micro;l for pain behavior). These findings demonstrate the existence of an endogenous compound in the brain that is similar to capsaicin and NADA in its chemical structure and activity on VR1. Unlike NADA, OLDA was only a weak ligand for rat CB1 receptors; but like NADA, it was recognized by the anandamide membrane transporter while being a poor substrate for fatty-acid amide hydrolase. Analysis of the activity of six additional synthetic and potentially endogenous N-acyldopamine indicated the requirement of a long unsaturated fatty acid chain for an optimal functional interaction with VR1 receptors
The Density and Temperature of Molecular Clouds in M33
We have observed the CO J=2-1, J=3-2, and CO J=2-1 lines in a
sample of seven giant molecular clouds in the Local Group spiral galaxy M33.
The CO/CO J=2-1 line ratio is constant across the entire sample,
while the observed CO J=3-2/J=2-1 line ratio has a weak dependence on
the star formation environment of the cloud, with large changes in the line
ratio seen only for clouds in the immediate vicinity of an extremely luminous
HII region. A large velocity gradient analysis indicates that clouds without
HII regions have temperatures of 10-20 K, clouds with HII regions have
temperatures of 15-100 K, and the cloud in the giant HII region has a
temperature of at least 100 K. Interestingly, the giant HII region appears
capable of raising the kinetic temperature of the molecular gas only for clouds
that are quite nearby ( pc). The continuous change of physical
conditions across the observed range of star formation environments suggests
that the unusual physical conditions in the cloud in the giant HII region are
due to post-star formation changes in the molecular gas, rather than intrinsic
properties of the gas related to the formation of the giant HII region.Comment: 14 pages, aastex, 4 postscript figures; accepted for publication in
ApJ; also available at http://www.physics.mcmaster.ca/Wilson_Preprint
Cosmological parameters from SDSS and WMAP
We measure cosmological parameters using the three-dimensional power spectrum
P(k) from over 200,000 galaxies in the Sloan Digital Sky Survey (SDSS) in
combination with WMAP and other data. Our results are consistent with a
``vanilla'' flat adiabatic Lambda-CDM model without tilt (n=1), running tilt,
tensor modes or massive neutrinos. Adding SDSS information more than halves the
WMAP-only error bars on some parameters, tightening 1 sigma constraints on the
Hubble parameter from h~0.74+0.18-0.07 to h~0.70+0.04-0.03, on the matter
density from Omega_m~0.25+/-0.10 to Omega_m~0.30+/-0.04 (1 sigma) and on
neutrino masses from <11 eV to <0.6 eV (95%). SDSS helps even more when
dropping prior assumptions about curvature, neutrinos, tensor modes and the
equation of state. Our results are in substantial agreement with the joint
analysis of WMAP and the 2dF Galaxy Redshift Survey, which is an impressive
consistency check with independent redshift survey data and analysis
techniques. In this paper, we place particular emphasis on clarifying the
physical origin of the constraints, i.e., what we do and do not know when using
different data sets and prior assumptions. For instance, dropping the
assumption that space is perfectly flat, the WMAP-only constraint on the
measured age of the Universe tightens from t0~16.3+2.3-1.8 Gyr to
t0~14.1+1.0-0.9 Gyr by adding SDSS and SN Ia data. Including tensors, running
tilt, neutrino mass and equation of state in the list of free parameters, many
constraints are still quite weak, but future cosmological measurements from
SDSS and other sources should allow these to be substantially tightened.Comment: Minor revisions to match accepted PRD version. SDSS data and ppt
figures available at http://www.hep.upenn.edu/~max/sdsspars.htm
Worldwide variations in artificial skyglow
Despite constituting a widespread and significant environmental change,
understanding of artificial nighttime skyglow is extremely limited. Until now,
published monitoring studies have been local or regional in scope, and
typically of short duration. In this first major international compilation of
monitoring data we answer several key questions about skyglow properties.
Skyglow is observed to vary over four orders of magnitude, a range hundreds of
times larger than was the case before artificial light. Nearly all of the
study sites were polluted by artificial light. A non-linear relationship is
observed between the sky brightness on clear and overcast nights, with a
change in behavior near the rural to urban landuse transition. Overcast skies
ranged from a third darker to almost 18 times brighter than clear. Clear sky
radiances estimated by the World Atlas of Artificial Night Sky Brightness were
found to be overestimated by ~25%; our dataset will play an important role in
the calibration and ground truthing of future skyglow models. Most of the
brightly lit sites darkened as the night progressed, typically by ~5% per
hour. The great variation in skyglow radiance observed from site-to-site and
with changing meteorological conditions underlines the need for a long-term
international monitoring program
Use of anticoagulants and antiplatelet agents in stable outpatients with coronary artery disease and atrial fibrillation. International CLARIFY registry
Implicating genes, pleiotropy, and sexual dimorphism at blood lipid loci through multi-ancestry meta-analysis
Publisher Copyright: © 2022, The Author(s).Background: Genetic variants within nearly 1000 loci are known to contribute to modulation of blood lipid levels. However, the biological pathways underlying these associations are frequently unknown, limiting understanding of these findings and hindering downstream translational efforts such as drug target discovery. Results: To expand our understanding of the underlying biological pathways and mechanisms controlling blood lipid levels, we leverage a large multi-ancestry meta-analysis (N = 1,654,960) of blood lipids to prioritize putative causal genes for 2286 lipid associations using six gene prediction approaches. Using phenome-wide association (PheWAS) scans, we identify relationships of genetically predicted lipid levels to other diseases and conditions. We confirm known pleiotropic associations with cardiovascular phenotypes and determine novel associations, notably with cholelithiasis risk. We perform sex-stratified GWAS meta-analysis of lipid levels and show that 3–5% of autosomal lipid-associated loci demonstrate sex-biased effects. Finally, we report 21 novel lipid loci identified on the X chromosome. Many of the sex-biased autosomal and X chromosome lipid loci show pleiotropic associations with sex hormones, emphasizing the role of hormone regulation in lipid metabolism. Conclusions: Taken together, our findings provide insights into the biological mechanisms through which associated variants lead to altered lipid levels and potentially cardiovascular disease risk.Peer reviewe
Implicating genes, pleiotropy, and sexual dimorphism at blood lipid loci through multi-ancestry meta-analysis
Abstract Background Genetic variants within nearly 1000 loci are known to contribute to modulation of blood lipid levels. However, the biological pathways underlying these associations are frequently unknown, limiting understanding of these findings and hindering downstream translational efforts such as drug target discovery. Results To expand our understanding of the underlying biological pathways and mechanisms controlling blood lipid levels, we leverage a large multi-ancestry meta-analysis (N = 1,654,960) of blood lipids to prioritize putative causal genes for 2286 lipid associations using six gene prediction approaches. Using phenome-wide association (PheWAS) scans, we identify relationships of genetically predicted lipid levels to other diseases and conditions. We confirm known pleiotropic associations with cardiovascular phenotypes and determine novel associations, notably with cholelithiasis risk. We perform sex-stratified GWAS meta-analysis of lipid levels and show that 3–5% of autosomal lipid-associated loci demonstrate sex-biased effects. Finally, we report 21 novel lipid loci identified on the X chromosome. Many of the sex-biased autosomal and X chromosome lipid loci show pleiotropic associations with sex hormones, emphasizing the role of hormone regulation in lipid metabolism. Conclusions Taken together, our findings provide insights into the biological mechanisms through which associated variants lead to altered lipid levels and potentially cardiovascular disease risk
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