848 research outputs found
The applications of deep neural networks to sdBV classification
With several new large-scale surveys on the horizon, including LSST, TESS,
ZTF, and Evryscope, faster and more accurate analysis methods will be required
to adequately process the enormous amount of data produced. Deep learning, used
in industry for years now, allows for advanced feature detection in minimally
prepared datasets at very high speeds; however, despite the advantages of this
method, its application to astrophysics has not yet been extensively explored.
This dearth may be due to a lack of training data available to researchers.
Here we generate synthetic data loosely mimicking the properties of acoustic
mode pulsating stars and we show that two separate paradigms of deep learning -
the Artificial Neural Network And the Convolutional Neural Network - can both
be used to classify this synthetic data effectively. And that additionally this
classification can be performed at relatively high levels of accuracy with
minimal time spent adjusting network hyperparameters.Comment: 12 pages, 10 figures, originally presented at sdOB
F14RS SGR No. 35 (Greek Recycling)
A RESOLUTION
To Urge and Request the Office of Campus Affairs and Sustainability to provide recycling bins for all participating greek houses
Updated High-Temperature Opacities for the Dartmouth Stellar Evolution Program and their Effect on the Jao Gap Location
The Jao Gap, a 17 percent decrease in stellar density at
identified in both Gaia DR2 and EDR3 data, presents a new method to probe the
interior structure of stars near the fully convective transition mass. The Gap
is believed to originate from convective kissing instability wherein asymmetric
production of He causes the core convective zone of a star to
periodically expand and contract and consequently the stars' luminosity to
vary. Modeling of the Gap has revealed a sensitivity in its magnitude to a
population's metallicity primarily through opacity. Thus far, models of the Jao
Gap have relied on OPAL high-temperature radiative opacities. Here we present
updated synthetic population models tracing the Gap location modeled with the
Dartmouth stellar evolution code using the OPLIB high-temperature radiative
opacities. Use of these updated opacities changes the predicted location of the
Jao Gap by mag as compared to models which use the OPAL opacities.
This difference is likely too small to be detectable in empirical data.Comment: 15 pages, 13 figures; Accepted for publication in The Astrophysical
Journa
Tobacco Use among Emergency Department Patients
This is the first study to systematically track the tobacco use prevalence in an entire emergency department (ED) population and compare age-stratified rates to the general population using national, provincial, and regional comparisons. A tobacco use question was integrated into the ED electronic registration process from 2007 to 2010 in 11 northern hospitals (10 rural, 1 urban). Results showed that tobacco use documentation (85–89%) and tobacco use (26–27%) were consistent across years with the only discrepancy being higher tobacco prevalence in 2007 (32%) due to higher rates at the urban hospital. Age-stratified outcomes showed that tobacco use remained high up to 50 years old (36%); rates began to decrease for patients in their 50’s (26%) and 60’s (16%), and decreased substantially after age 70 (5%). The age-stratified ED tobacco rates were almost double those of the general population nationally and provincially for all but the oldest age groups but were virtually identical to regional rates. The tobacco use tracking and age-stratified general population comparisons in this study improves on previous attempts to document prevalence in the ED population, and at a more local level, provides a “big picture” overview that highlights the magnitude of the tobacco-use problem in these communities
Electron microscopic analysis of rotavirus assembly-replication intermediates
AbstractRotaviruses (RVs) replicate their segmented, double-stranded RNA genomes in tandem with early virion assembly. In this study, we sought to gain insight into the ultrastructure of RV assembly-replication intermediates (RIs) using transmission electron microscopy (EM). Specifically, we examined a replicase-competent, subcellular fraction that contains all known RV RIs. Three never-before-seen complexes were visualized in this fraction. Using in vitro reconstitution, we showed that ~15-nm doughnut-shaped proteins in strings were nonstructural protein 2 (NSP2) bound to viral RNA transcripts. Moreover, using immunoaffinity-capture EM, we revealed that ~20-nm pebble-shaped complexes contain the viral RNA polymerase (VP1) and RNA capping enzyme (VP3). Finally, using a gel purification method, we demonstrated that ~30–70-nm electron-dense, particle-shaped complexes represent replicase-competent core RIs, containing VP1, VP3, and NSP2 as well as capsid proteins VP2 and VP6. The results of this study raise new questions about the interactions among viral proteins and RNA during the concerted assembly–replicase process
2-deoxyglucose inhibits induction of chemokine expression in 3T3-L1 adipocytes and adipose tissue explants
© 2016 The Obesity Society Objective: To determine the influence of glycolytic inhibition on the adipocyte inflammatory response. Methods: To determine the effect of 2-deoxyglucose (2-DOG) on the inflammatory response, mature 3T3-L1 adipocytes were co-treated with 2-DOG and LPS or TNF. To determine the effect of endoplasmic reticulum stress on TNF-induced induction of chemokines, adipocytes were pretreated with thapsigargin or salubrinal. Chemokine mRNA levels were determined using quantitative real-time PCR, and secretion of CCL2 was determined by Western blot. Results: 2-DOG treatment reduced the ability of LPS and TNF to induce CCL2 mRNA levels and reduced secreted CCL2 protein levels in a dose-dependent manner. A similar pattern of mRNA regulation was observed for other chemokines. The attenuation of TNF-induced CCL2 mRNA levels occurred regardless of whether glucose or pyruvate was present in the media, suggesting that mechanisms other than glycolysis might mediate the observed effects. Treatment with the endoplasmic reticulum stressor thapsigargin and the endoplasmic reticulum signaling activator salubrinal reduced chemokine mRNA levels similarly to 2-DOG. Conclusions: Collectively, our data indicate that 2-DOG suppresses inflammatory chemokine induction in adipocytes. The effects of 2-DOG do not seem to be linked to glycolysis but correlate with endoplasmic reticulum stress activation
Alcohol Use Disorder in the Age of Technology: A Review of Wearable Biosensors in Alcohol Use Disorder Treatment
Biosensors enable observation and understanding of latent physiological occurrences otherwise unknown or invasively detected. Wearable biosensors monitoring physiological constructs across a wide variety of mental and physical health conditions have become an important trend in innovative research methodologies. Within substance use research, explorations of biosensor technology commonly focus on identifying physiological indicators of intoxication to increase understanding of addiction etiology and to inform treatment recommendations. In this review, we examine the state of research in this area as it pertains to treatment of alcohol use disorders specifically highlighting the gaps in our current knowledge with recommendations for future research. Annually, alcohol use disorders affect approximately 15 million individuals. A primary focus of existing wearable technology-based research among people with alcohol use disorders is identifying alcohol intoxication. A large benefit of wearable biosensors for this purpose is they provide continuous readings in a passive manner compared with the gold standard measure of blood alcohol content (BAC) traditionally measured intermittently by breathalyzer or blood draw. There are two primary means of measuring intoxication with biosensors: gait and sweat. Gait changes have been measured via smart sensors placed on the wrist, in the shoe, and mobile device sensors in smart phones. Sweat measured by transdermal biosensors detects the presence of alcohol in the blood stream correlating to BAC. Transdermal biosensors have been designed in tattoos/skin patches, shirts, and most commonly, devices worn on the ankle or wrist. Transdermal devices were initially developed to help monitor court-ordered sobriety among offenders with alcohol use disorder. These devices now prove most useful in continuously tracking consumption throughout clinical trials for behavioral treatment modalities. More recent research has started exploring the uses for physical activity trackers and physiological arousal sensors to guide behavioral interventions for relapse prevention. While research has begun to demonstrate wearable devices\u27 utility in reducing alcohol consumption among individuals aiming to cutdown on their drinking, monitoring sustained abstinence in studies exploring contingency management for alcohol use disorders, and facilitating engagement in activity-based treatment interventions, their full potential to further aid in understanding of, and treatment for, alcohol use disorders has yet to be explored
A search for rapidly pulsating hot subdwarf stars in the GALEX survey
NASA's Galaxy Evolution Explorer (GALEX) provided near- and far-UV
observations for approximately 77 percent of the sky over a ten-year period;
however, the data reduction pipeline initially only released single NUV and FUV
images to the community. The recently released Python module gPhoton changes
this, allowing calibrated time-series aperture photometry to be extracted
easily from the raw GALEX data set. Here we use gPhoton to generate light
curves for all hot subdwarf B (sdB) stars that were observed by GALEX, with the
intention of identifying short-period, p-mode pulsations. We find that the
spacecraft's short visit durations, uneven gaps between visits, and dither
pattern make the detection of hot subdwarf pulsations difficult. Nonetheless,
we detect UV variations in four previously known pulsating targets and report
their UV pulsation amplitudes and frequencies. Additionally, we find that
several other sdB targets not previously known to vary show promising signals
in their periodograms. Using optical follow-up photometry with the Skynet
Robotic Telescope Network, we confirm p-mode pulsations in one of these
targets, LAMOST J082517.99+113106.3, and report it as the most recent addition
to the sdBVr class of variable stars.Comment: 11 Pages, 8 Figures, Accepted for publication in the Astrophysical
Journa
The Absolute Age of M92
The \textit{absolute age} of a simple stellar population is of fundamental
interest for a wide range of applications but is difficult to measure in
practice, as it requires an understanding of the uncertainties in a variety of
stellar evolution processes as well as the uncertainty in the distance,
reddening and composition. As a result, most studies focus only on the
\textit{relative age} by assuming that stellar evolution calculations are
accurate and using age determinations techniques that are relatively
independent of distance and reddening. Here, we construct sets of
theoretical isochrones through Monte Carlo simulation using the Dartmouth
Stellar Evolution Program to measure the absolute age of the globular cluster
M92. For each model, we vary a range of input physics used in the stellar
evolution models, including opacities, nuclear reaction rates, diffusion
coefficients, atmospheric boundary conditions, helium abundance, and treatment
of convection. We also explore variations in the distance and reddening as well
as its overall metallicity and enhancement. We generate simulated Hess
diagrams around the main-sequence turn-off region from each set of isochrones
and use a Voronoi binning method to fit the diagrams to HST ACS data. We find
the age of M92 to be Gyr. The error in the absolute
age is dominated by the uncertainty in the distance to M92 ( of the
error budget); of the remaining parameters, only the total metallicity,
element abundance, and treatment of helium diffusion contribute
significantly to the total error.Comment: 15 Pages, 14 Figures, 2 Tables; Accepted for Publication A
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