2,270 research outputs found
The Frequency of Barred Spiral Galaxies in the Near-IR
We have determined the fraction of barred galaxies in the H-band for a
statistically well-defined sample of 186 spirals drawn from the Ohio State
University Bright Spiral Galaxy survey. We find 56% of our sample to be
strongly barred at H, while another 16% is weakly barred. Only 27% of our
sample is unbarred in the near-infrared. The RC3 and the Carnegie Atlas of
Galaxies both classify only about 30% of our sample as strongly barred. Thus
strong bars are nearly twice as prevalent in the near-infrared as in the
optical. The frequency of genuine optically hidden bars is significant, but
lower than many claims in the literature: 40% of the galaxies in our sample
that are classified as unbarred in the RC3 show evidence for a bar in the
H-band, while for the Carnegie Atlas this fraction is 66%. Our data reveal no
significant trend in bar fraction as a function of morphology in either the
optical or H-band. Optical surveys of high redshift galaxies may be strongly
biased against finding bars, as bars are increasingly difficult to detect at
bluer rest wavelengths.Comment: LaTeX with AASTeX style file, 23 pages with 6 figures. Accepted for
publication in The Astronomical Journal (Feb. 2000
HST-NICMOS Observations of M31's Metal Rich Globular Clusters and Their Surrounding Fields: II. Results
We have obtained HST-NICMOS observations of five of M31's most metal rich
globular clusters: G1, G170, G174, G177 & G280. For the two clusters farthest
from the nucleus we statistically subtract the field population and estimate
metallicities using K-(J-K) color-magnitude diagrams (CMDs). Based on the
slopes of their infrared giant branches we estimate [Fe/H]=-1.22+/-0.43 for G1
and -0.15+/-0.37 for G280. We combine our infrared observations of G1 with two
epochs of optical HST-WFPC2 V-band data and identify at least one LPV based on
color and variability. The location of G1's giant branch in the K-(V-K) CMD is
very similar to that of M107, indicating a higher metallicity than our purely
infrared CMD: [Fe/H]=-0.9+/-0.2.
For the field surrounding G280, we estimate the metallicity to be -1.3 with a
spread of 0.5 from the slope and width of the giant branch. Based on the
numbers and luminosities of the brightest giants, we conclude that only a small
fraction of the stars in this field could be as young as 2 Gyr, while the
majority have ages closer to 10 Gyr.
The K-band luminosity functions (LFs) of the upper few magnitudes of G1 and
G280, as well as for the fields surrounding all clusters, are indistinguishable
from the LF measured in the bulge of our Galaxy. This indicates that these
clusters are very similar to Galactic clusters, and at least in the surrounding
fields observed, there are no significant populations of young luminous stars.Comment: AAS LaTeX v5.0, 17 pages. Submitted to the A
HST/ACS Imaging of Omega Centauri: Optical Counterpart for the Quiescent Low-Mass X-Ray Binary
We report the discovery of an optical counterpart to a quiescent neutron star
in the globular cluster Omega Centauri (NGC 5139). The star was found as part
of our wide-field imaging study of Omega Cen using the Advanced Camera for
Surveys (ACS) on Hubble Space Telescope. Its magnitude and color (R_625 = 25.2,
B_435 - R_625 = 1.5) place it more than 1.5 magnitudes to the blue side of the
main sequence. Through an H-alpha filter it is ~ 1.3 magnitudes brighter than
cluster stars of comparable M_625 magnitude. The blue color and H-alpha excess
suggest the presence of an accretion disk, implying that the neutron star is
accreting from a binary companion and is thus a quiescent low-mass X-ray
binary. If the companion is a main-sequence star, then the faint absolute
magnitude (M_625 ~ 11.6) constrains it to be of very low mass (M <~ 0.14
Msolar). The faintness of the disk (M_435 ~ 13) suggests a very low rate of
accretion onto the neutron star. We also detect 13 probable white dwarfs and
three possible BY Draconis stars in the 20" x 20" region analyzed here,
suggesting that a large number of white dwarfs and active binaries will be
observable in the full ACS study.Comment: Accepted for Publication in the Astrophysical Journal. 5 pages, 4
figures, 1 table, uses emulateapj.sty. Figures 1 and 3 at reduced resolution.
New version contains revised magnitude calibration
Perioperative pain management and opioid-reduction in head and neck endocrine surgery: An American Head and Neck Society Endocrine Surgery Section consensus statement
BACKGROUND: This American Head and Neck Society (AHNS) consensus statement focuses on evidence-based comprehensive pain management practices for thyroid and parathyroid surgery. Overutilization of opioids for postoperative pain management is a major contributing factor to the opioid addiction epidemic however evidence-based guidelines for pain management after routine head and neck endocrine procedures are lacking.
METHODS: An expert panel was convened from the membership of the AHNS, its Endocrine Surgical Section, and ThyCa. An extensive literature review was performed, and recommendations addressing several pain management subtopics were constructed based on best available evidence. A modified Delphi survey was then utilized to evaluate group consensus of these statements.
CONCLUSIONS: This expert consensus provides evidence-based recommendations for effective postoperative pain management following head and neck endocrine procedures with a focus on limiting unnecessary use of opioid analgesics
Synthesis of Well-Defined, Surfactant-Free Co<sub>3</sub>O<sub>4</sub> Nanoparticles:The Impact of Size and Manganese Promotion on Co<sub>3</sub>O<sub>4</sub> Reduction and Water Oxidation Activity
Abstract: A surfactant-free synthetic route has been developed to produce size-controlled, cube-like cobalt oxide nanoparticles of three different sizes in high yields. It was found that by using sodium nitrite as salt-mediating agent, near-quantitative yields could be obtained. The size of the nanoparticles could be altered from 11 to 22Â nm by changing the cobalt concentration and reaction time. These surfactant-free nanoparticles form ideal substrates for facile deposition of further elements such as manganese. The effect of size of the cobalt oxide nanoparticles and the presence of manganese on the reducibility of cobalt oxide to metallic cobalt was investigated. Similarly, the effect of these parameters was investigated with a visible light promoted water oxidation system with cobalt oxide as catalyst, together with [Ru(bpy) 3] 2+ light harvester dye and an electron acceptor. Graphical Abstract: A novel surfactant-free synthetic route has been developed to produce size-controlled, cube shaped cobalt oxide nanoparticles in high yields. [Figure not available: see fulltext.]. </p
Pediatric Procedural Pain
Reviews the various settings in which infants, children, and adolescents experience pain during acute medical procedures, and issues related to referral of children to pain management teams. In addition, self-report, reports by others, physiological monitoring, and direct observation methods of assessment of pain and related constructs are discussed and recommendations provided. Pharmacological, other medical approaches, and empirically supported cognitive behavioral interventions are reviewed. Salient features of the interventions are discussed and recommendations are made for necessary components of effective treatment interventions
Varespladib and cardiovascular events in patients with an acute coronary syndrome: the VISTA-16 randomized clinical trial
IMPORTANCE: Secretory phospholipase A2(sPLA2) generates bioactive phospholipid products implicated in atherosclerosis. The sPLA2inhibitor varespladib has favorable effects on lipid and inflammatory markers; however, its effect on cardiovascular outcomes is unknown. OBJECTIVE: To determine the effects of sPLA2inhibition with varespladib on cardiovascular outcomes. DESIGN, SETTING, AND PARTICIPANTS: A double-blind, randomized, multicenter trial at 362 academic and community hospitals in Europe, Australia, New Zealand, India, and North America of 5145 patients randomized within 96 hours of presentation of an acute coronary syndrome (ACS) to either varespladib (n = 2572) or placebo (n = 2573) with enrollment between June 1, 2010, and March 7, 2012 (study termination on March 9, 2012). INTERVENTIONS: Participants were randomized to receive varespladib (500 mg) or placebo daily for 16 weeks, in addition to atorvastatin and other established therapies. MAIN OUTCOMES AND MEASURES: The primary efficacy measurewas a composite of cardiovascular mortality, nonfatal myocardial infarction (MI), nonfatal stroke, or unstable angina with evidence of ischemia requiring hospitalization at 16 weeks. Six-month survival status was also evaluated. RESULTS: At a prespecified interim analysis, including 212 primary end point events, the independent data and safety monitoring board recommended termination of the trial for futility and possible harm. The primary end point occurred in 136 patients (6.1%) treated with varespladib compared with 109 patients (5.1%) treated with placebo (hazard ratio [HR], 1.25; 95%CI, 0.97-1.61; log-rank P = .08). Varespladib was associated with a greater risk of MI (78 [3.4%] vs 47 [2.2%]; HR, 1.66; 95%CI, 1.16-2.39; log-rank P = .005). The composite secondary end point of cardiovascular mortality, MI, and stroke was observed in 107 patients (4.6%) in the varespladib group and 79 patients (3.8%) in the placebo group (HR, 1.36; 95% CI, 1.02-1.82; P = .04). CONCLUSIONS AND RELEVANCE: In patients with recent ACS, varespladib did not reduce the risk of recurrent cardiovascular events and significantly increased the risk of MI. The sPLA2inhibition with varespladib may be harmful and is not a useful strategy to reduce adverse cardiovascular outcomes after ACS. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01130246. Copyright 2014 American Medical Association. All rights reserved
The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe
The preponderance of matter over antimatter in the early Universe, the
dynamics of the supernova bursts that produced the heavy elements necessary for
life and whether protons eventually decay --- these mysteries at the forefront
of particle physics and astrophysics are key to understanding the early
evolution of our Universe, its current state and its eventual fate. The
Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed
plan for a world-class experiment dedicated to addressing these questions. LBNE
is conceived around three central components: (1) a new, high-intensity
neutrino source generated from a megawatt-class proton accelerator at Fermi
National Accelerator Laboratory, (2) a near neutrino detector just downstream
of the source, and (3) a massive liquid argon time-projection chamber deployed
as a far detector deep underground at the Sanford Underground Research
Facility. This facility, located at the site of the former Homestake Mine in
Lead, South Dakota, is approximately 1,300 km from the neutrino source at
Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino
charge-parity symmetry violation and mass ordering effects. This ambitious yet
cost-effective design incorporates scalability and flexibility and can
accommodate a variety of upgrades and contributions. With its exceptional
combination of experimental configuration, technical capabilities, and
potential for transformative discoveries, LBNE promises to be a vital facility
for the field of particle physics worldwide, providing physicists from around
the globe with opportunities to collaborate in a twenty to thirty year program
of exciting science. In this document we provide a comprehensive overview of
LBNE's scientific objectives, its place in the landscape of neutrino physics
worldwide, the technologies it will incorporate and the capabilities it will
possess.Comment: Major update of previous version. This is the reference document for
LBNE science program and current status. Chapters 1, 3, and 9 provide a
comprehensive overview of LBNE's scientific objectives, its place in the
landscape of neutrino physics worldwide, the technologies it will incorporate
and the capabilities it will possess. 288 pages, 116 figure
Comprehensive characterization of 536 patient-derived xenograft models prioritizes candidates for targeted treatment
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