160 research outputs found
Burden of Substance Abuse-Related Admissions to the Medical ICU
Background
Admissions to the ICU related to alcohol, prescription drugs, and illicit drugs are shown to be widespread and costly. In 1993, a study revealed 28% of ICU admissions at Johns Hopkins Hospital were related to substance abuse and accrued 39% of costs. Since then, health-care expenditures have increased, and substance abuse treatment admissions have risen. We conducted a study to provide updated data on ICU utilization and costs related to licit and illicit abuse at a large county hospital in Indianapolis, Indiana.
Methods
All admissions to the medical ICU at Eskenazi Hospital from March to October 2017 were reviewed. Demographics, reason for admission, relation to substance abuse and specific substance, ICU and hospital length of stay, Acute Physiology and Chronic Health Evaluation II (APACHE II) scores, mortality, insurance status, and hospital charges were collected based on chart review.
Results
A total of 611 admissions generated $74,587,280.35 in charges. A total of 25.7% of admissions related to substance abuse accounted for 23.1% of total charges. Illicit drugs were 13% of total admissions, generating 11% of charges. Alcohol-related admissions were 9.5% of total admissions, generating 7.6% of charges. Prescription drugs were 2.9% of admissions, generating 4.2% of charges. Of the substance abuse admissions, patients were generally men and 40 to 64 years of age, with longer ICU stay, higher APACHE II scores, and higher mortality.
Conclusions
Substance abuse admissions make up almost a one-quarter of resources used by our ICU. Patients tend to be younger and sicker with a higher risk of death. Identifying and accurately describing the landscape of this current health crisis will help us take appropriate action in the future
Sex bias in CNS autoimmune disease mediated by androgen control of autoimmune regulator
Male gender is protective against multiple sclerosis and other T-cell-mediated autoimmune diseases. This protection may be due, in part, to higher androgen levels in males. Androgen binds to the androgen receptor (AR) to regulate gene expression, but how androgen protects against autoimmunity is not well understood. Autoimmune regulator (Aire) prevents autoimmunity by promoting self-antigen expression in medullary thymic epithelial cells, such that developing T cells that recognize these self-antigens within the thymus undergo clonal deletion. Here we show that androgen upregulates Aire-mediated thymic tolerance to protect against autoimmunity. Androgen recruits AR to Aire promoter regions, with consequent enhancement of Aire transcription. In mice and humans, thymic Aire expression is higher in males compared with females. Androgen administration and male gender protect against autoimmunity in a multiple sclerosis mouse model in an Aire-dependent manner. Thus, androgen control of an intrathymic Aire-mediated tolerance mechanism contributes to gender differences in autoimmunity
Testing Models of Intrinsic Brightness Variations in Type Ia Supernovae, and their Impact on Measuring Cosmological Parameters
For spectroscopically confirmed Type Ia supernovae we evaluate models of
intrinsic brightness variations with detailed data/Monte Carlo comparisons of
the dispersion in the following quantities: Hubble-diagram scatter, color
difference (B-V-c) between the true B-V color and the fitted color (c) from the
SALT-II light curve model, and photometric redshift residual. The data sample
includes 251 ugriz light curves from the 3-season Sloan Digital Sky Survey-II,
and 191 griz light curves from the Supernova Legacy Survey 3-year data release.
We find that the simplest model of a wavelength-independent (coherent) scatter
is not adequate, and that to describe the data the intrinsic scatter model must
have wavelength-dependent variations. We use Monte Carlo simulations to examine
the standard approach of adding a coherent scatter term in quadrature to the
distance-modulus uncertainty in order to bring the reduced chi2 to unity when
fitting a Hubble diagram. If the light curve fits include model uncertainties
with the correct wavelength dependence of the scatter, we find that the bias on
the dark energy equation of state parameter is negligible. However,
incorrect model uncertainties can lead to a significant bias on the distance
moduli, with up to ~0.05 mag redshift-dependent variation. For the recent SNLS3
cosmology results we estimate that this effect introduces an additional
systematic uncertainty on of ~0.02, well below the total uncertainty.
However, this uncertainty depends on the samples used, and thus this small
-uncertainty is not guaranteed in future cosmology results.Comment: accepted by Ap
Single or Double Degenerate Progenitors? Searching for Shock Emission in the SDSS-II Type Ia Supernovae
From the set of nearly 500 spectroscopically confirmed type~Ia supernovae and
around 10,000 unconfirmed candidates from SDSS-II, we select a subset of 108
confirmed SNe Ia with well-observed early-time light curves to search for
signatures from shock interaction of the supernova with a companion star. No
evidence for shock emission is seen; however, the cadence and photometric noise
could hide a weak shock signal. We simulate shocked light curves using SN Ia
templates and a simple, Gaussian shock model to emulate the noise properties of
the SDSS-II sample and estimate the detectability of the shock interaction
signal as a function of shock amplitude, shock width, and shock fraction. We
find no direct evidence for shock interaction in the rest-frame -band, but
place an upper limit on the shock amplitude at 9% of supernova peak flux ( mag). If the single degenerate channel dominates type~Ia progenitors,
this result constrains the companion stars to be less than about 6
on the main sequence, and strongly disfavors red giant companions.Comment: 28 pages, 3 figure
Results from the Supernova Photometric Classification Challenge
We report results from the Supernova Photometric Classification Challenge
(SNPCC), a publicly released mix of simulated supernovae (SNe), with types (Ia,
Ibc, and II) selected in proportion to their expected rate. The simulation was
realized in the griz filters of the Dark Energy Survey (DES) with realistic
observing conditions (sky noise, point-spread function and atmospheric
transparency) based on years of recorded conditions at the DES site.
Simulations of non-Ia type SNe are based on spectroscopically confirmed light
curves that include unpublished non-Ia samples donated from the Carnegie
Supernova Project (CSP), the Supernova Legacy Survey (SNLS), and the Sloan
Digital Sky Survey-II (SDSS-II). A spectroscopically confirmed subset was
provided for training. We challenged scientists to run their classification
algorithms and report a type and photo-z for each SN. Participants from 10
groups contributed 13 entries for the sample that included a host-galaxy
photo-z for each SN, and 9 entries for the sample that had no redshift
information. Several different classification strategies resulted in similar
performance, and for all entries the performance was significantly better for
the training subset than for the unconfirmed sample. For the spectroscopically
unconfirmed subset, the entry with the highest average figure of merit for
classifying SNe~Ia has an efficiency of 0.96 and an SN~Ia purity of 0.79. As a
public resource for the future development of photometric SN classification and
photo-z estimators, we have released updated simulations with improvements
based on our experience from the SNPCC, added samples corresponding to the
Large Synoptic Survey Telescope (LSST) and the SDSS, and provided the answer
keys so that developers can evaluate their own analysis.Comment: accepted by PAS
The Carnegie Supernova Project: First Near-Infrared Hubble Diagram to z~0.7
The Carnegie Supernova Project (CSP) is designed to measure the luminosity
distance for Type Ia supernovae (SNe Ia) as a function of redshift, and to set
observational constraints on the dark energy contribution to the total energy
content of the Universe. The CSP differs from other projects to date in its
goal of providing an I-band {rest-frame} Hubble diagram. Here we present the
first results from near-infrared (NIR) observations obtained using the Magellan
Baade telescope for SNe Ia with 0.1 < z < 0.7. We combine these results with
those from the low-redshift CSP at z <0.1 (Folatelli et al. 2009). We present
light curves and an I-band Hubble diagram for this first sample of 35 SNe Ia
and we compare these data to 21 new SNe Ia at low redshift. These data support
the conclusion that the expansion of the Universe is accelerating. When
combined with independent results from baryon acoustic oscillations (Eisenstein
et al. 2005), these data yield Omega_m = 0.27 +/- 0.0 (statistical), and
Omega_DE = 0.76 +/- 0.13 (statistical) +/- 0.09 (systematic), for the matter
and dark energy densities, respectively. If we parameterize the data in terms
of an equation of state, w, assume a flat geometry, and combine with baryon
acoustic oscillations, we find that w = -1.05 +/- 0.13 (statistical) +/- 0.09
(systematic). The largest source of systematic uncertainty on w arises from
uncertainties in the photometric calibration, signaling the importance of
securing more accurate photometric calibrations for future supernova cosmology
programs. Finally, we conclude that either the dust affecting the luminosities
of SNe Ia has a different extinction law (R_V = 1.8) than that in the Milky Way
(where R_V = 3.1), or that there is an additional intrinsic color term with
luminosity for SNe Ia independent of the decline rate.Comment: 44 pages, 23 figures, 9 tables; Accepted for publication in the
Astrophysical Journa
SN 2009bb: a Peculiar Broad-Lined Type Ic Supernova
Ultraviolet, optical, and near-infrared photometry and optical spectroscopy
of the broad-lined Type Ic supernova (SN) 2009bb are presented, following the
flux evolution from -10 to +285 days past B-band maximum. Thanks to the very
early discovery, it is possible to place tight constraints on the SN explosion
epoch. The expansion velocities measured from near maximum spectra are found to
be only slightly smaller than those measured from spectra of the prototype
broad-lined SN 1998bw associated with GRB 980425. Fitting an analytical model
to the pseudo-bolometric light curve of SN 2009bb suggests that 4.1+-1.9 Msun
of material was ejected with 0.22 +-0.06 Msun of it being 56Ni. The resulting
kinetic energy is 1.8+-0.7x10^52 erg. This, together with an absolute peak
magnitude of MB=-18.36+-0.44, places SN 2009bb on the energetic and luminous
end of the broad-lined Type Ic (SN Ic) sequence. Detection of helium in the
early time optical spectra accompanied with strong radio emission, and high
metallicity of its environment makes SN 2009bb a peculiar object. Similar to
the case for GRBs, we find that the bulk explosion parameters of SN 2009bb
cannot account for the copious energy coupled to relativistic ejecta, and
conclude that another energy reservoir (a central engine) is required to power
the radio emission. Nevertheless, the analysis of the SN 2009bb nebular
spectrum suggests that the failed GRB detection is not imputable to a large
angle between the line-of-sight and the GRB beamed radiation. Therefore, if a
GRB was produced during the SN 2009bb explosion, it was below the threshold of
the current generation of gamma-ray instruments.Comment: Accepted for publication in Ap
Type Ia Supernova Properties as a Function of the Distance to the Host Galaxy in the SDSS-II SN Survey
We use type-Ia supernovae (SNe Ia) discovered by the SDSS-II SN Survey to
search for dependencies between SN Ia properties and the projected distance to
the host galaxy center, using the distance as a proxy for local galaxy
properties (local star-formation rate, local metallicity, etc.). The sample
consists of almost 200 spectroscopically or photometrically confirmed SNe Ia at
redshifts below 0.25. The sample is split into two groups depending on the
morphology of the host galaxy. We fit light-curves using both MLCS2k2 and
SALT2, and determine color (AV, c) and light-curve shape (delta, x1) parameters
for each SN Ia, as well as its residual in the Hubble diagram. We then
correlate these parameters with both the physical and the normalized distances
to the center of the host galaxy and look for trends in the mean values and
scatters of these parameters with increasing distance. The most significant (at
the 4-sigma level) finding is that the average fitted AV from MLCS2k2 and c
from SALT2 decrease with the projected distance for SNe Ia in spiral galaxies.
We also find indications that SNe in elliptical galaxies tend to have narrower
light-curves if they explode at larger distances, although this may be due to
selection effects in our sample. We do not find strong correlations between the
residuals of the distance moduli with respect to the Hubble flow and the
galactocentric distances, which indicates a limited correlation between SN
magnitudes after standardization and local host metallicity.Comment: Accepted for publication in The Astrophysical Journal (33 pages, 5
figures, 8 tables
A Mismatch in the Ultraviolet Spectra between Low-Redshift and Intermediate-Redshift Type Ia Supernovae as a Possible Systematic Uncertainty for Supernova Cosmology
We present Keck high-quality rest-frame ultraviolet (UV) through optical
spectra of 21 Type Ia supernovae (SNe Ia) in the redshift range 0.11 < z < 0.37
and a mean redshift of 0.22 that were discovered during the Sloan Digital Sky
Survey-II (SDSS-II) SN Survey. Using the broad-band photometry of the SDSS
survey, we are able to reconstruct the SN host-galaxy spectral energy
distributions (SEDs), allowing for a correction for the host-galaxy
contamination in the SN Ia spectra. Comparison of composite spectra constructed
from a subsample of 17 high-quality spectra to those created from a
low-redshift sample with otherwise similar properties shows that the Keck/SDSS
SNe Ia have, on average, extremely similar rest-frame optical spectra but show
a UV flux excess. This observation is confirmed by comparing synthesized
broad-band colors of the individual spectra, showing a difference in mean
colors at the 2.4 - 4.4 sigma level for various UV colors. We further see a
slight difference in the UV spectral shape between SNe with low-mass and
high-mass host galaxies. Additionally, we detect a relationship between the
flux ratio at 2770 and 2900 A and peak luminosity that differs from that
observed at low redshift. We find that changing the UV SED of an SN Ia within
the observed dispersion can change the inferred distance moduli by ~0.1 mag.
This effect only occurs when the data probe the rest-frame UV. We suggest that
this discrepancy could be due to differences in the host-galaxy population of
the two SN samples or to small-sample statistics.Comment: 28 pages, 21 figures, accepted by AJ, spectra are available at
http://www.cfa.harvard.edu/~rfoley/data
First-year Sloan Digital Sky Survey-II (SDSS-II) Supernova Results: Hubble Diagram and Cosmological Parameters
We present measurements of the Hubble diagram for 103 Type Ia supernovae
(SNe) with redshifts 0.04 < z < 0.42, discovered during the first season (Fall
2005) of the Sloan Digital Sky Survey-II (SDSS-II) Supernova Survey. These data
fill in the redshift "desert" between low- and high-redshift SN Ia surveys. We
combine the SDSS-II measurements with new distance estimates for published SN
data from the ESSENCE survey, the Supernova Legacy Survey, the Hubble Space
Telescope, and a compilation of nearby SN Ia measurements. Combining the SN
Hubble diagram with measurements of Baryon Acoustic Oscillations from the SDSS
Luminous Red Galaxy sample and with CMB temperature anisotropy measurements
from WMAP, we estimate the cosmological parameters w and Omega_M, assuming a
spatially flat cosmological model (FwCDM) with constant dark energy equation of
state parameter, w. For the FwCDM model and the combined sample of 288 SNe Ia,
we find w = -0.76 +- 0.07(stat) +- 0.11(syst), Omega_M = 0.306 +- 0.019(stat)
+- 0.023(syst) using MLCS2k2 and w = -0.96 +- 0.06(stat) +- 0.12(syst), Omega_M
= 0.265 +- 0.016(stat) +- 0.025(syst) using the SALT-II fitter. We trace the
discrepancy between these results to a difference in the rest-frame UV model
combined with a different luminosity correction from color variations; these
differences mostly affect the distance estimates for the SNLS and HST
supernovae. We present detailed discussions of systematic errors for both
light-curve methods and find that they both show data-model discrepancies in
rest-frame -band. For the SALT-II approach, we also see strong evidence for
redshift-dependence of the color-luminosity parameter (beta). Restricting the
analysis to the 136 SNe Ia in the Nearby+SDSS-II samples, we find much better
agreement between the two analysis methods but with larger uncertainties.Comment: Accepted for publication by ApJ
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