Model Averaging Software for Dichotomous Dose Response Risk Estimation

Model averaging has been shown to be a useful method for incorporating model uncertainty in quantitative risk estimation. In certain circumstances this technique is computationally complex, requiring sophisticated software to carry out the computation. We introduce software that implements model averaging for risk assessment based upon dichotomous dose-response data. This software, which we call Model Averaging for Dichotomous Response Benchmark Dose (MADr-BMD), fits the quantal response models, which are also used in the US Environmental Protection Agency benchmark dose software suite, and generates a model-averaged dose response model to generate benchmark dose and benchmark dose lower bound estimates. The software fulfills a need for risk assessors, allowing them to go beyond one single model in their risk assessments based on quantal data by focusing on a set of models that describes the experimental data.

Model Averaging Software for Dichotomous Dose Response Risk Estimation

Model averaging has been shown to be a useful method for incorporating model uncertainty in quantitative risk estimation. In certain circumstances this technique is computationally complex, requiring sophisticated software to carry out the computation. We introduce software that implements model averaging for risk assessment based upon dichotomous dose-response data. This software, which we call Model Averaging for Dichotomous Response Benchmark Dose (MADr-BMD), fits the quantal response models, which are also used in the US Environmental Protection Agency benchmark dose software suite, and generates a model-averaged dose response model to generate benchmark dose and benchmark dose lower bound estimates. The software fulfills a need for risk assessors, allowing them to go beyond one single model in their risk assessments based on quantal data by focusing on a set of models that describes the experimental data

Web Application to Investigate Butler County Overdose Death Data

Background: Drug overdose deaths, specifically opioid-related deaths, are a public health crisis in the United States with high incidence observed in many Midwestern states, including Ohio. Butler County, Ohio, has the third highest opioid-related death rate in the state. Information on overdose deaths, collected by the county coroner, can serve as a data source for analysis of this public health concern. Given this access, stakeholders can investigate trends in their community for their idiosyncratic interest.Methods: A web application was developed, using the R Shiny package, to visualize and explore the characteris-tics of all overdose deaths in Butler County between 2013 and 2018. Demographics of the decedents, drugs found in the decedents’ postmortem toxicology analyses, annual trends in overdose deaths, and the location of these cases can be examined.Results: The web application provides a graphical user interface that allows a user to request specific analyses and summaries. “Who is dying from opioid overdoses?,” “What drugs, including opioids, are found in people dying from drug overdoses?,” and “Has the number of opioid involved deaths increased in a specific community over time?” are examples of questions that can be explored using this application.Conclusion: This application empowers both the public and local policymakers to investigate the impact of overdose deaths on their communities. Understanding characteristics of the epidemic is an important first step to addressing this problem. The expansion of this application to include other counties in Ohio could be truly beneficial to communities that need it

Worker Injuries and Safety Equipment in Ohio Nursing Homes

A survey of nursing homes was conducted in 2006 to evaluate a number of facility-specific characteristics including worker injury rates. The nursing home worker injury rate was 6.6 per 100 workers with higher injury rates observed in larger facilities, homes that were part of chains and homes with a higher proportion of wheelchair bound residents. A broad range of patient-transfer safety equipment was observed to be in use; however, the presence of these devices were not predictive of lower worker injury rates

Balmer filaments in Tycho's supernova remnant: an interplay between cosmic-ray and broad-neutral precursors

We present H$\alpha$ spectroscopic observations and detailed modelling of the Balmer filaments in the supernova remnant Tycho. We used Galaxy H$\alpha$ Fabry-P\'erot Spectrometer on the William Herschel Telescope with a 3.4'$\times$3.4' field-of-view, 0.2" pixel scale and \sigma_\rm{instr}=8.1 km/s resolution at 1" seeing for $\sim10$ hours, resulting in 82 spatial-spectral bins that resolve the narrow H$\alpha$ line in the entire Tycho's northeastern rim. For the first time, we can mitigate artificial line broadening from unresolved differential motion, and probe H$\alpha$ emission parameters in varying shock and ambient medium conditions. Broad H$\alpha$ line remains unresolved within spectral coverage of 392 km/s. We employed Bayesian inference to obtain reliable parameter confidence intervals, and quantify the evidence for models with multiple line components. The median H$\alpha$ narrow-line full-width at half-maximum of all bins and models is W_\rm{NL}=(54.8\pm1.8) km/s at the $95\%$ confidence level, varying within [35, 72] km/s between bins and clearly broadened compared to the intrinsic (thermal) $\approx20$ km/s. Possible line splits are accounted for, significant in $\approx18\%$ of the filament, and presumably due to remaining projection effects. We also find wide-spread evidence for intermediate-line emission of a broad-neutral precursor, with median W_\rm{IL}=(180\pm14) km/s ($95\%$ confidence). Finally, we present a measurement of the remnant's systemic velocity, V_\rm{LSR}=-34 km/s, and map differential line-of-sight motions. Our results confirm the existence and interplay of shock precursors in Tycho's remnant. In particular, we show that suprathermal narrow-line emission is near-universal in Tycho and that, in absence of an alternative explanation, collisionless supernova remnant shocks constitute a viable acceleration source for Galactic TeV Cosmic-Ray protons.Comment: 36 pages, 17 figures, 5 tables, Paper accepted for publication in the Astrophysical Journal; References correcte

Balmer-dominated shocks in Tycho's SNR: omnipresence of CRs

We present wide-field, spatially and highly resolved spectroscopic observations of Balmer filaments in the northeastern rim of Tycho's supernova remnant in order to investigate the signal of cosmic-ray (CR) acceleration. The spectra of Balmer-dominated shocks (BDSs) have characteristic narrow (FWHM $\sim$ 10 kms$^{-1}$) and broad (FWHM $\sim$ 1000 kms$^{-1}$) H$\alpha$ components. CRs affect the H$\alpha$-line parameters: heating the cold neutrals in the interstellar medium results in broadening of the narrow H$\alpha$-line width beyond 20 kms$^{-1}$, but also in reduction of the broad H$\alpha$-line width due to energy being removed from the protons in the post-shock region. For the first time we show that the width of the narrow H$\alpha$ line, much larger than 20 kms$^{-1}$, is not a resolution or geometric effect nor a spurious result of a neglected intermediate (FWHM $\sim$ 100 kms$^{-1}$) component resulting from hydrogen atoms undergoing charge exchange with warm protons in the broad-neutral precursor. Moreover, we show that a narrow line width $\gg$ 20 kms$^{-1}$ extends across the entire NE rim, implying CR acceleration is ubiquitous, and making it possible to relate its strength to locally varying shock conditions. Finally, we find several locations along the rim, where spectra are significantly better explained (based on Bayesian evidence) by inclusion of the intermediate component, with a width of 180 kms$^{-1}$ on average.Comment: Proceeding for contributed talk at the IAU Symposium No. 331: "SN 1987A, 30 years later - Cosmic Rays and Nuclei from Supernovae and their Aftermaths", 2017, La Reunion Island; References correcte

Weather on the Nearest Brown Dwarfs: Resolved Simultaneous Multi-Wavelength Variability Monitoring of WISE J104915.57-531906.1AB

We present two epochs of MPG/ESO 2.2m GROND simultaneous 6-band ($r'i'z'JHK$) photometric monitoring of the closest known L/T transition brown dwarf binary WISE J104915.57-531906.1AB. We report here the first resolved variability monitoring of both the T0.5 and L7.5 components. We obtained 4 hours of focused observations on the night of UT 2013-04-22, as well as 4 hours of defocused (unresolved) observations on the night of UT 2013-04-16. We note a number of robust trends in our light curves. The $r'$ and $i'$ light curves appear to be anticorrelated with $z'$ and $H$ for the T0.5 component and in the unresolved lightcurve. In the defocused dataset, $J$ appears correlated with $z'$ and $H$ and anticorrelated with $r'$ and $i'$, while in the focused dataset we measure no variability for $J$ at the level of our photometric precision, likely due to evolving weather phenomena. In our focused T0.5 component lightcurve, the $K$ band lightcurve displays a significant phase offset relative to both $H$ and $z'$. We argue that the measured phase offsets are correlated with atmospheric pressure probed at each band, as estimated from 1D atmospheric models. We also report low-amplitude variability in $i'$ and $z'$ intrinsic to the L7.5 component.Comment: 14 pages, 5 figures, accepted to ApJ Letter

The SEGUE Stellar Parameter Pipeline. II. Validation with Galactic Globular and Open Clusters

We validate the performance and accuracy of the current SEGUE (Sloan Extension for Galactic Understanding and Exploration) Stellar Parameter Pipeline (SSPP), which determines stellar atmospheric parameters (effective temperature, surface gravity, and metallicity) by comparing derived overall metallicities and radial velocities from selected likely members of three globular clusters (M 13, M 15, and M 2) and two open clusters (NGC 2420 and M 67) to the literature values. Spectroscopic and photometric data obtained during the course of the original Sloan Digital Sky Survey (SDSS-I) and its first extension (SDSS-II/SEGUE) are used to determine stellar radial velocities and atmospheric parameter estimates for stars in these clusters. Based on the scatter in the metallicities derived for the members of each cluster, we quantify the typical uncertainty of the SSPP values, sigma([Fe/H]) = 0.13 dex for stars in the range of 4500 K < Teff < 7500 K and 2.0 < log g < 5.0, at least over the metallicity interval spanned by the clusters studied (-2.3 < [Fe/H] < 0). The surface gravities and effective temperatures derived by the SSPP are also compared with those estimated from the comparison of the color-magnitude diagrams with stellar evolution models; we find satisfactory agreement. At present, the SSPP underestimates [Fe/H] for near-solar-metallicity stars, represented by members of M 67 in this study, by about 0.3 dex.Comment: 56 pages, 8 Tables, 15 figures, submitted to the Astronomical Journa

The Spectra of T Dwarfs I: Near-Infrared Data and Spectral Classification

We present near-infrared spectra for a sample of T dwarfs, including eleven new discoveries made using the Two Micron All Sky Survey. These objects are distinguished from warmer (L-type) brown dwarfs by the presence of methane absorption bands in the 1--2.5 \micron spectral region. A first attempt at a near-infrared classification scheme for T dwarfs is made, based on the strengths of CH$_4$ and H$_2$O bands and the shapes of the 1.25, 1.6, and 2.1 \micron flux peaks. Subtypes T1 V through T8 V are defined, and spectral indices useful for classification are presented. The subclasses appear to follow a decreasing T$_{eff}$ scale, based on the evolution of CH$_4$ and H$_2$O bands and the properties of L and T dwarfs with known distances. However, we speculate that this scale is not linear with spectral type for cool dwarfs, due to the settling of dust layers below the photosphere and subsequent rapid evolution of spectral morphology around T$_{eff}$ $\sim$ 1300--1500 K. Similarities in near-infrared colors and continuity of spectral features suggest that the gap between the latest L dwarfs and earliest T dwarfs has been nearly bridged. This argument is strengthened by the possible role of CH$_4$ as a minor absorber shaping the K-band spectra of the latest L dwarfs. Finally, we discuss one peculiar T dwarf, 2MASS 0937+2931, which has very blue near-infrared colors (J-K$_s$ = $-0.89\pm$0.24) due to suppression of the 2.1 \micron peak. The feature is likely caused by enhanced collision-induced H$_2$ absorption in a high pressure or low metallicity photosphere.Comment: 74 pages including 26 figures, accepted by ApJ v563 December 2001; full paper including all of Table 3 may be downloaded from http://www.gps.caltech.edu/~pa/adam/classification ;also see submission 010844

The SEGUE Stellar Parameter Pipeline. I. Description and Initial Validation Tests

We describe the development and implementation of the SEGUE (Sloan Extension for Galactic Exploration and Understanding) Stellar Parameter Pipeline (SSPP). The SSPP derives, using multiple techniques, radial velocities and the fundamental stellar atmospheric parameters (effective temperature, surface gravity, and metallicity) for AFGK-type stars, based on medium-resolution spectroscopy and $ugriz$ photometry obtained during the course of the original Sloan Digital Sky Survey (SDSS-I) and its Galactic extension (SDSS-II/SEGUE). The SSPP also provides spectral classification for a much wider range of stars, including stars with temperatures outside of the window where atmospheric parameters can be estimated with the current approaches. This is Paper I in a series of papers on the SSPP; it provides an overview of the SSPP, and initial tests of its performance using multiple data sets. Random and systematic errors are critically examined for the current version of the SSPP, which has been used for the sixth public data release of the SDSS (DR-6).Comment: 64 pages, 8 tables, 12 figures, submitted to the Astronomical Journa