796 research outputs found
Empirical Verification of the Fe II Oscillator Strengths in the FUSE Bandpass
We report empirical determinations of atomic oscillator strengths, or
f-values, for 11 ground-state transitions of Fe II in the wavelength range 1050
to 1150 Ang. We use ultraviolet absorption line observations of interstellar
material towards stars in the Galaxy and the Magellanic Clouds taken with
Copernicus, the Goddard High Resolution Spectrograph on-board the Hubble Space
Telescope, and the Far Ultraviolet Spectroscopic Explorer. We derive absolute
oscillator strengths by a combination of the apparent optical depth, component
fitting, and curve-of-growth fitting techniques. Our derived oscillator
strengths are generally in excellent agreement with recent theoretical
calculations by Raassen & Uylings using the orthogonal operator technique.
However, we identify three of the eleven transitions studied here whose
f-values seem to be incompatible with these calculations, by as much as a
factor of two. We suggest revisions to these f-values based upon our analysis.Comment: To appear in the Astrophysical Journal. 31 pages, including 8
embedded tables and 10 embedded figures. Also available at
http://fuse.pha.jhu.edu/~howk/Papers
Outpatient facility-based order variation in combined imaging.
OBJECTIVE: Combined computed tomography (CT) occurs when one anatomical area is simultaneously imaged both without and with contrast, or two overlapping anatomical areas are imaged concurrently. While this has been studied in a Traditional Medicare population, it has not been studied in other populations subject to prior authorization. This study explores between-facility variation in ordering and receiving orders to render combined CT in a mixed commercial and Medicare Advantage population.
METHODS: Orders for CT abdomen (without/with contrast), CT thorax (without/with contrast), and concurrent CT brain and sinus authorized by a prior authorization company from 2013-2017, pertaining to patients with commercial or Medicare Advantage health plans from one national insurer, were extracted. Orders were issued and rendered by both hospitals and nonhospitals. The analysis was performed separately for each anatomical area in two ways: orders were grouped by ordering facility, and by designated rendering facility. For each facility, the ratio of combined to total orders was calculated, and analysis of variance was used to determine whether there were significant differences in this rate by year. The association between health plan type and combined imaging rates was assessed.
RESULTS: Combined rates [ratio±standard deviation] for abdomen, thorax, and brain/sinus were 0.306±0.246, 0.089±0.142, and 0.002±0.01 respectively when the analysis was conducted according to ordering facility, and 0.311±0.178, 0.096±0.113, and 0.001±0.006 when the analysis was conducted according to designated rendering facility. Combined CT abdomen and CT thorax rates decreased monotonically from 2013 to 2017, decreases that were significant (P \u3c .01) regardless of whether orders were grouped by ordering or rendering facility. Combined CT abdomen and CT thorax rates significantly differed between orders pertaining to people with commercial and Medicare Advantage plans.
DISCUSSION: Variability was greater when orders were grouped by ordering facility, rather than rendering facility. Health plan type may influence whether a patient receives combined CT
NetKet 3: Machine Learning Toolbox for Many-Body Quantum Systems
We introduce version 3 of NetKet, the machine learning toolbox for many-body quantum physics. NetKet is built around neural-network quantum states and provides efficient algorithms for their evaluation and optimization. This new version is built on top of JAX, a differentiable programming and accelerated linear algebra framework for the Python programming language. The most significant new feature is the possibility to define arbitrary neural network ansätze in pure Python code using the concise notation of machine-learning frameworks, which allows for just-in-time compilation as well as the implicit generation of gradients thanks to automatic differentiation. NetKet 3 also comes with support for GPU and TPU accelerators, advanced support for discrete symmetry groups, chunking to scale up to thousands of degrees of freedom, drivers for quantum dynamics applications, and improved modularity, allowing users to use only parts of the toolbox as a foundation for their own code
Relationship between alirocumab, PCSK9, and LDL-C levels in four phase 3 ODYSSEY trials using 75 and 150 mg doses
BACKGROUND: Alirocumab is a monoclonal antibody to proprotein convertase subtilisin/kexin type 9 (PCSK9). OBJECTIVE: Changes in PCSK9, alirocumab, and low-density lipoprotein cholesterol (LDL-C) levels were assessed after treatment with alirocumab at doses of 75 or 150 mg every 2 weeks (Q2W). METHODS: Data were analyzed from 4 phase 3 trials (MONO; COMBO II; FH I; LONG TERM); all but MONO enrolled patients on statins. Three trials evaluated alirocumab 75 mg Q2W, with possible dose increase to 150 mg Q2W at week 12 based on week 8 LDL-C; LONG TERM studied alirocumab 150 mg Q2W. RESULTS: Patients on background statin therapy had higher mean baseline free PCSK9 concentrations vs patients not on statin. After alirocumab administration, increased alirocumab concentrations were associated with dramatic reductions in circulating free PCSK9, resulting in significant LDL-C reductions and a corresponding increase in inactive PCSK9:alirocumab complex. Alirocumab dose increase was associated with a further lowering of PCSK9 and LDL-C. Patients with higher baseline LDL-C levels (>160 mg/dL) were more likely to have their dose increased. LDL-C reductions with alirocumab were consistent between patients with baseline PCSK9 levels above or below the median when the dose increase strategy was used. When started as alirocumab 150 mg Q2W, patients with PCSK9 levels above vs below the median had a greater LDL-C reduction. CONCLUSIONS: Alirocumab-induced changes in PCSK9 and LDL-C levels were consistent with the known physiologic relationship between PCSK9, LDL receptor, and LDL-C levels, as well as statin-induced increases in PCSK9 production. (C) 2019 National Lipid Association. Published by Elsevier Inc.Peer reviewe
A Nationally Representative Survey Assessing Restorative Sleep in US Adults
Restorative sleep is a commonly used term but a poorly defined construct. Few studies have assessed restorative sleep in nationally representative samples. We convened a panel of 7 expert physicians and researchers to evaluate and enhance available measures of restorative sleep. We then developed the revised Restorative Sleep Questionnaire (REST-Q), which comprises 9 items assessing feelings resulting from the prior sleep episode, each with 5-point Likert response scales. Finally, we assessed the prevalence of high, somewhat, and low REST-Q scores in a nationally representative sample of US adults (n= 1,055) and examined the relationship of REST-Q scores with other sleep and demographic characteristics. Pairwise correlations were performed between the REST-Q scores and other self-reported sleep measures. Weighted logistic regression analyses were conducted to compare scores on the REST-Q with demographic variables. The prevalence of higher REST-Q scores (4 or 5 on the Likert scale) was 28.1% in the nationally representative sample. REST-Q scores positively correlated with sleep quality (r=0.61) and sleep duration (r=0.32), and negatively correlated with both difficulty falling asleep (r=-0.40) and falling back asleep after waking (r=-0.41). Higher restorative sleep scores (indicating more feelings of restoration upon waking) were more common among those who were: ≥60 years of age (OR=4.20, 95%CI: 1.92-9.17); widowed (OR=2.35, 95%CI:1.01-5.42), and retired (OR=2.02, 95%CI:1.30-3.14). Higher restorative sleep scores were less frequent among those who were not working (OR=0.36, 95%CI: 0.10-1.00) and living in a household with two or more persons (OR=0.51,95%CI:0.29-0.87). Our findings suggest that the REST-Q may be useful for assessing restorative sleep
Carnegie Supernova Project-II: Extending the Near-Infrared Hubble Diagram for Type Ia Supernovae to
The Carnegie Supernova Project-II (CSP-II) was an NSF-funded, four-year
program to obtain optical and near-infrared observations of a "Cosmology"
sample of Type Ia supernovae located in the smooth Hubble flow (). Light curves were also obtained of a "Physics"
sample composed of 90 nearby Type Ia supernovae at selected for
near-infrared spectroscopic time-series observations. The primary emphasis of
the CSP-II is to use the combination of optical and near-infrared photometry to
achieve a distance precision of better than 5%. In this paper, details of the
supernova sample, the observational strategy, and the characteristics of the
photometric data are provided. In a companion paper, the near-infrared
spectroscopy component of the project is presented.Comment: 43 pages, 10 figures, accepted for publication in PAS
The Peculiar SN 2005hk: Do Some Type Ia Supernovae Explode as Deflagrations?
We present extensive u'g'r'i'BVRIYJHKs photometry and optical spectroscopy of
SN 2005hk. These data reveal that SN 2005hk was nearly identical in its
observed properties to SN 2002cx, which has been called ``the most peculiar
known type Ia supernova.'' Both supernovae exhibited high ionization SN
1991T-like pre-maximum spectra, yet low peak luminosities like SN 1991bg. The
spectra reveal that SN 2005hk, like SN 2002cx, exhibited expansion velocities
that were roughly half those of typical type Ia supernovae. The R and I light
curves of both supernovae were also peculiar in not displaying the secondary
maximum observed for normal type Ia supernovae. Our YJH photometry of SN 2005hk
reveals the same peculiarity in the near-infrared. By combining our optical and
near-infrared photometry of SN 2005hk with published ultraviolet light curves
obtained with the Swift satellite, we are able to construct a bolometric light
curve from ~10 days before to ~60 days after B maximum. The shape and unusually
low peak luminosity of this light curve, plus the low expansion velocities and
absence of a secondary maximum at red and near-infrared wavelengths, are all in
reasonable agreement with model calculations of a 3D deflagration which
produces ~0.25 M_sun of 56Ni.Comment: Accepted by PASP, to appear in April 2007 issue, 63 pages, 16
figures, 11 table
HETDEX pilot survey for emission-line galaxies - I. Survey design, performance, and catalog
We present a catalog of emission-line galaxies selected solely by their
emission-line fluxes using a wide-field integral field spectrograph. This work
is partially motivated as a pilot survey for the upcoming Hobby-Eberly
Telescope Dark Energy Experiment (HETDEX). We describe the observations,
reductions, detections, redshift classifications, line fluxes, and counterpart
information for 397 emission-line galaxies detected over 169 sq.arcmin with a
3500-5800 Ang. bandpass under 5 Ang. full-width-half-maximum (FWHM) spectral
resolution. The survey's best sensitivity for unresolved objects under
photometric conditions is between 4-20 E-17 erg/s/sq.cm depending on the
wavelength, and Ly-alpha luminosities between 3-6 E42 erg/s are detectable.
This survey method complements narrowband and color-selection techniques in the
search for high redshift galaxies with its different selection properties and
large volume probed. The four survey fields within the COSMOS, GOODS-N, MUNICS,
and XMM-LSS areas are rich with existing, complementary data. We find 104
galaxies via their high redshift Ly-alpha emission at 1.9<z<3.8, and the
majority of the remainder objects are low redshift [OII]3727 emitters at
z<0.56. The classification between low and high redshift objects depends on
rest frame equivalent width, as well as other indicators, where available.
Based on matches to X-ray catalogs, the active galactic nuclei (AGN) fraction
amongst the Ly-alpha emitters (LAEs) is 6%. We also analyze the survey's
completeness and contamination properties through simulations. We find five
high-z, highly-significant, resolved objects with full-width-half-maximum sizes
>44 sq.arcsec which appear to be extended Ly-alpha nebulae. We also find three
high-z objects with rest frame Ly-alpha equivalent widths above the level
believed to be achievable with normal star formation, EW(rest)>240 Ang.Comment: 45 pages, 36 figures, 5 tables, submitted to ApJ
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
Contemporary multicenter outcomes of continent cutaneous ileocecocystoplasty in the adult population over a 10-year period: A Neurogenic Bladder Research Group study
AIMS: Evidence is sparse on the long-term outcomes of continent cutaneous ileocecocystoplasty (CCIC). We hypothesized that obesity, laparoscopic/robotic approach, and concomitant surgeries would affect morbidity after CCIC and aimed to evaluate the outcomes of CCIC in adults in a multicenter contemporary study.
METHODS: We retrospectively reviewed the charts of adult patients from sites in the Neurogenic Bladder Research Group undergoing CCIC (2007-2017) who had at least 6 months of follow-up. We evaluated patient demographics, surgical details, 90-day complications, and follow-up surgeries. the Mann-Whitney U test was used to compare continuous variables and χ² and Fisher\u27s Exact tests were used to compare categorical variables.
RESULTS: We included 114 patients with a median age of 41 years. The median postoperative length of stay was 8 days. At 3 months postoperatively, major complications occurred in 18 (15.8%), and 24 patients (21.1%) were readmitted. During a median follow-up of 40 months, 48 patients (42.1%) underwent 80 additional related surgeries. Twenty-three patients (20.2%) underwent at least one channel revision, most often due to obstruction (15, 13.2%) or incontinence (4, 3.5%). Of the channel revisions, 10 (8.8%) were major and 14 (12.3%) were minor. Eleven patients (9.6%) abandoned the catheterizable channel during the follow-up period. Obesity and laparoscopic/robotic surgical approach did not affect outcomes, though concomitant surgery was associated with a higher rate of follow-up surgeries.
CONCLUSIONS: In this contemporary multicenter series evaluating CCIC, we found that the short-term major complication rate was low, but many patients require follow-up surgeries, mostly related to the catheterizable channel
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