2,784 research outputs found
Detection of continuous variable entanglement without coherent local oscillators
We propose three criteria for identifying continuous variable entanglement
between two many-particle systems with no restrictions on the quantum state of
the local oscillators used in the measurements. Mistakenly asserting a coherent
state for the local oscillator can lead to incorrectly identifying the presence
of entanglement. We demonstrate this in simulations with 100 particles, and
also find that large number fluctuations do not prevent the observation of
entanglement. Our results are important for quantum information experiments
with realistic Bose-Einstein condensates or in optics with arbitrary photon
states.Comment: 7 Pages, 4 Figure
Associations between social risk factors and surgical site infections after colectomy and abdominal hysterectomy
Importance: Surgical site infection (SSI) is an important patient safety outcome. Although social risk factors have been linked to many adverse health outcomes, it is unknown whether such factors are associated with higher rates of SSI.
Objectives: To determine whether social risk factors, including race/ethnicity, insurance status, and neighborhood income, are associated with higher rates of SSI after colectomy or abdominal hysterectomy, 2 surgical procedures for which SSI rates are publicly reported and included in pay-for-performance programs by Medicare and other groups.
Design, Setting, and Participants: This cross-sectional study analyzed adults undergoing colectomy or abdominal hysterectomy, as captured in State Inpatient Databases for Arizona, Florida, Iowa, Massachusetts, Maryland, New York, and Vermont. Operations were performed in 2013 through 2014 at general acute care hospitals in the United States. Data analysis was conducted from October 2018 through June 2019.
Exposures: Colectomy or hysterectomy.
Main Outcomes and Measures: Postoperative complex SSI rates.
Results: A total of 149âŻ741 patients met the inclusion criteria, including 90âŻ210 patients undergoing colectomies (mean [SD] age, 63.4 [15.6] years; 49âŻ029 [54%] female; 74% white, 11% black, 9% Hispanic, and 5% other or unknown race/ethnicity) and 59âŻ531 patients undergoing abdominal hysterectomies (mean [SD] age, 49.8 [11.8] years; 100% female; 52% white, 26% black, 14% Hispanic, and 8% other or unknown race/ethnicity). In the colectomy cohort, 34% had private insurance, 52% had Medicare, 9% had Medicaid, and 5% had other or unknown insurance or were uninsured; 24% were from the lowest quartile of median zip code income. In the hysterectomy cohort, 57% had private insurance, 16% had Medicare, 19% had Medicaid, and 3% had other or unknown insurance or were uninsured; 27% were from the lowest-income zip codes. Within 30 days of surgery, SSI rates were 2.55% for the colectomy cohort and 0.61% for the hysterectomy cohort. For colectomy, black race (adjusted odds ratio [AOR],â0.71; 95% CI, 0.61-0.82) was associated with lower odds of SSI, whereas Medicare (AOR,â1.25; 95% CI, 1.10-1.41), Medicaid (AOR,â1.23; 95% CI, 1.06-1.44), and low neighborhood income (AOR,â1.14; 95% CI, 1.01-1.29) were associated with higher odds of SSI. For hysterectomy, no social risk factors that were examined in this study had statistically significant associations with SSI after adjustment for clinical risk.
Conclusions and Relevance: Inconsistent associations between social risk factors and SSIs were found. For colectomy, infection prevention programs targeting low-income groups may be important for reducing disparities in this postoperative outcome, and policy makers could consider taking social risk factors into account when evaluating hospital performance
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Greater Sage-Grouse Demography, Habitat Selection, and Habitat Connectivity in Relation to Western Juniper and its Management
The expansion of native, woody plants is a global phenomenon with characteristics and effects that are often indistinguishable from exotic invasions. These expansions have largely been driven by altered fire regimes and favorable climatic conditions. In the Great Basin of western North America, expansion of conifers such as western juniper (Juniperus occidentalis) is a considered a primary threat to sagebrush (Artemisia spp.) ecosystems. The greater sage-grouse (Centrocercus urophasianus; sage-grouse), a sagebrush obligate gallinaceous bird, utilizes sagebrush during every phase of its lifecycle. Sage-grouse have declined across their range and currently occupy approximately 56% of their pre-European settlement distribution. Management agencies are actively removing conifers that established after European settlement (~1870) in the Great Basin to restore sagebrush ecosystem function and benefit species such as sage-grouse that are inextricably tied these landscapes. The literature on the response of sage-grouse to these broad-scale management actions is limited. My study utilized a âbefore-after-control-impactâ study design to investigate the response of sage-grouse populations, habitat selection, and habitat connectivity to conifer removal. I was able to build upon a radio telemetry data set that began in 2010 and with my work included a total sample of 417 females, their nests (n = 378), and broods (n = 233) for demographic and resource selection modeling.
In Chapter 2, I developed a hierarchical population model in a Bayesian framework that integrated telemetry data and lek (i.e., breeding arena) count data to estimate sage-grouse vital rates and population growth rates in a treatment area with conifer removal (Treatment) and a control area (Control). The model indicated that dynamics in population growth rates (λ) approximately tracked each other in the Treatment and Control. However, starting in 2013 (conifer removals initiated in 2012), λ in the Treatment steadily increased relative to the Control and was 11.2% higher by 2017. This trend was driven by increases in juvenile, adult, first nest, and yearling survival in the Treatment relative to the Control. These findings indicated that conifer removal is an effective technique for restoring sagebrush ecosystem function and increasing sage-grouse population growth rates.
In Chapter 3, I estimated resource selection functions for sage-grouse nest site and breeding season habitat selection. Conifer cover and conifer removal variables were among the most influential predictors of nest site and breeding season habitat selection. Sage-grouse selected nest sites in and near older conifer removal areas and were 16% less likely to nest in an area for every 1% increase in conifer cover within 400 m of the nest. During the breeding season, sage-grouse selected habitat closer to conifer removals and were 26% more likely to use a removal each year post-removal (1â5 years post-removal). By 2017, 75% of the treatment area was in the medium-high and high probability of use categories resulting from conifer removal, up from 49% in 2010. These findings demonstrated the efficacy of conifer removal for increasing usable space for sage-grouse in landscapes affected by conifer expansion.
In Chapter 4, I modeled the landscape connectivity in the Treatment with resistance surfaces generated with a resource selection function. The change in resistance resulting from conifer removal was quantified within the habitat utilized by sage-grouse, which was modeled with Brownian bridge movement models and straight-line, movement pathways. Regardless of the habitat use metric used, there was a reduction in landscape resistance in the areas used by sage-grouse in the post-conifer removal period. When comparing areas used by females with broods and those without, breeding season home ranges of females without broods experienced greater increases (â€81% increase) in connectivity after conifer removal. These differences in landscape resistance held when comparing females with broods and those without in a given post-removal year. These findings indicated that conifer removal is an effective method of restoring landscape connectivity in landscapes affected by post-European settlement expansion of conifers. The difference in benefits for females with and without broods may have demographic implications and needs further investigation.
I sought to evaluate the response of sage-grouse to landscape-scale conifer removal. Collectively, I demonstrated increased population growth rates, usable space, and landscape connectivity resulting from conifer removal. While the extent of sagebrush ecosystems affected by conifer expansion in the Great Basin and the larger sage-grouse range is immense, these findings indicated that targeted conifer removal is an effective management technique to improve the ecosystem function of these landscapes and benefit sage-grouse and likely other sagebrush obligates
A statistical gap-filling method to interpolate global monthly surface ocean carbon dioxide data
We have developed a statistical gap-ïŹlling method adapted to the speciïŹc coverage and prop-erties of observed fugacity of surface ocean CO2(fCO2). We have used this method to interpolate the Sur-face Ocean CO2Atlas (SOCAT) v2 database on a 2.5832.58 global grid (south of 708N) for 1985â2011 atmonthly resolution. The method combines a spatial interpolation based on a ââradius of inïŹuenceââ to deter-mine nearby similar fCO2values with temporal harmonic and cubic spline curve-ïŹtting, and also ïŹts long-term trends and seasonal cycles. Interannual variability is established using deviations of observations fromthe ïŹtted trends and seasonal cycles. An uncertainty is computed for all interpolated values based on thespatial and temporal range of the interpolation. Tests of the method using model data show that it performsas well as or better than previous regional interpolation methods, but in addition it provides a near-globaland interannual coverage
PHAT Stellar Cluster Survey I. Year 1 Catalog and Integrated Photometry
The Panchromatic Hubble Andromeda Treasury (PHAT) survey is an on-going
Hubble Space Telescope (HST) multi-cycle program to obtain high spatial
resolution imaging of one-third of the M31 disk at ultraviolet through
near-infrared wavelengths. In this paper, we present the first installment of
the PHAT stellar cluster catalog. When completed, the PHAT cluster catalog will
be among the largest and most comprehensive surveys of resolved star clusters
in any galaxy. The exquisite spatial resolution achieved with HST has allowed
us to identify hundreds of new clusters that were previously inaccessible with
existing ground-based surveys. We identify 601 clusters in the Year 1 sample,
representing more than a factor of four increase over previous catalogs within
the current survey area (390 arcmin^2). This work presents results derived from
the first \sim25% of the survey data; we estimate that the final sample will
include \sim2500 clusters. For the Year 1 objects, we present a catalog with
positions, radii, and six-band integrated photometry. Along with a general
characterization of the cluster luminosities and colors, we discuss the cluster
luminosity function, the cluster size distributions, and highlight a number of
individually interesting clusters found in the Year 1 search.Comment: 26 pages, 22 figures, Accepted by Ap
Intra- and inter-pandemic variations of antiviral, antibiotics and decongestants in wastewater treatment plants and receiving rivers
The concentration of eleven antibiotics (trimethoprim, oxytetracycline, ciprofloxacin, azithromycin, cefotaxime, doxycycline, sulfamethoxazole, erythromycin, clarithromycin, ofloxacin, norfloxacin), three decongestants (naphazoline, oxymetazoline, xylometazoline) and the antiviral drug oseltamivirâs active metabolite, oseltamivir carboxylate (OC), were measured weekly at 21 locations within the River Thames catchment in England during the month of November 2009, the autumnal peak of the influenza A[H1N1]pdm09 pandemic. The aim was to quantify the pharmaceutical response to the pandemic and compare this to drug use during the late pandemic (March 2010) and the inter-pandemic periods (May 2011). A large and small wastewater treatment plant (WWTP) were sampled in November 2009 to understand the differential fate of the analytes in the two WWTPs prior to their entry in the receiving river and to estimate drug users using a wastewater epidemiology approach. Mean hourly OC concentrations in the small and large WWTPâs influent were 208 and 350 ng/L (max, 2070 and 550 ng/L, respectively). Erythromycin was the most concentrated antibiotic measured in Benson and Oxford WWTPs influent (max = 6,870 and 2,930 ng/L, respectively). Napthazoline and oxymetazoline were the most frequently detected and concentrated decongestant in the Benson WWTP influent (1650 and 67 ng/L) and effluent (696 and 307 ng/L), respectively, but were below detection in the Oxford WWTP. OC was found in 73% of November 2009âs weekly river samples (max = 193 ng/L), but only in 5% and 0% of the late- and inter-pandemic river samples, respectively. The mean river concentration of each antibiotic during the pandemic largely fell between 17â74 ng/L, with clarithromycin (max = 292 ng/L) and erythromycin (max = 448 ng/L) yielding the highest single measure. In general, the concentration and frequency of detecting antibiotics in the river increased during the pandemic. OC was uniquely well-suited for the wastewater epidemiology approach owing to its nature as a prodrug, recalcitrance and temporally- and spatially-resolved prescription statistics
The ACS Nearby Galaxy Survey Treasury
The ACS Nearby Galaxy Survey Treasury (ANGST) is a systematic survey to
establish a legacy of uniform multi-color photometry of resolved stars for a
volume-limited sample of nearby galaxies (D<4 Mpc). The survey volume
encompasses 69 galaxies in diverse environments, including close pairs, small &
large groups, filaments, and truly isolated regions. The galaxies include a
nearly complete range of morphological types spanning a factor of ~10^4 in
luminosity and star formation rate. The survey data consists of images taken
with ACS on HST, supplemented with archival data and new WFPC2 imaging taken
after the failure of ACS. Survey images include wide field tilings covering the
full radial extent of each galaxy, and single deep pointings in uncrowded
regions of the most massive galaxies in the volume. The new wide field imaging
in ANGST reaches median 50% completenesses of m_F475W=28.0 mag, m_F606W=27.3
mag, and m_F814W=27.3 mag, several magnitudes below the tip of the red giant
branch (TRGB). The deep fields reach magnitudes sufficient to fully resolve the
structure in the red clump. The resulting photometric catalogs are publicly
accessible and contain over 34 million photometric measurements of >14 million
stars. In this paper we present the details of the sample selection, imaging,
data reduction, and the resulting photometric catalogs, along with an analysis
of the photometric uncertainties (systematic and random), for both the ACS and
WFPC2 imaging. We also present uniformly derived relative distances measured
from the apparent magnitude of the TRGB.Comment: 54 pages, including 24 pages of figures and 16 pages of tables.
Project website and data available at http://www.nearbygalaxies.org/ . Data
is also available through MAST. Scheduled to appear in the Astrophysical
Journal Supplements. (Replaced to fix several figures that were damaged
during compression
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