11,560 research outputs found
Preoperative nuclear stress testing in the very old patient population
© The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved. BACKGROUND Elderly patients awaiting moderate to high-risk surgery may undergo nuclear stress testing (NST) in order to evaluate their cardiovascular risk. The prognostic utility of such testing in the very elderly (≥ 85 years) has yet to be fully evaluated. Octogenarians and nonogenarians frequently have a number of concurrent conditions including a high rate of coronary disease, and therefore the prognostic value of NST for their preoperative risk assessment has been questioned. Our evaluation assesses the ability of nuclear stress testing to predict peri-operative cardiac outcomes in this patient population. AIM To investigate the ability of NST to predict peri-operative cardiac outcomes in elderly patients awaiting moderate to high-risk surgery. METHODS Patients ≥ 85 years undergoing pre-operative NST were retrospectively evaluated. Patients undergoing low-risk surgery were excluded. Major adverse cardiac events (MACE) were considered any adverse event that occurred prior to discharge and included acute heart failure, arrhythmia, acute myocardial infarction, unstable angina, or death. Associations between patient risk factors, MACE, and the obtained results of the pre-operative stress testing, ejection fraction (\u3c 40% or ≥ 40%), summed stress score (≤ 8, ≥ 9), and the summed difference score (≤ 0, \u3e 0) were analyzed. RESULTS A total of 69 patients (mean age 88 ± 2.6 years, 31 males) underwent nuclear stress testing prior to surgery. There were 41 (60%) patients found to have an abnormal NST. Sixteen (23%) patients were noted to experience post-operative MACE. No significant associations between risk factors and MACE were noted. Patients with an abnormal NST and/or a summed stress score ≥ 9 were significantly (P \u3c 0.01) more likely to develop peri-operative MACE
The opposites task: Using general rules to test cognitive flexibility in preschoolers
A brief narrative description of the journal article, document, or resource. Executive functions play an important role in cognitive development, and during the preschool years especially, children's performance is limited in tasks that demand flexibility in their behavior. We asked whether preschoolers would exhibit limitations when they are required to apply a general rule in the context of novel stimuli on every trial (the "opposites" task). Two types of inhibitory processing were measured: response interference (resistance to interference from a competing response) and proactive interference (resistance to interference from a previously relevant rule). Group data show 3-year-olds have difficulty inhibiting prepotent tendencies under these conditions, whereas 5-year-olds' accuracy is near ceiling in the task. (Contains 4 footnotes and 1 table.
Unraveling the Infrared Transient VVV-WIT-06: The Case for the Origin as a Classical Nova
Indexación: Scopus.E.Y.H. acknowledges the support provided by the National Science Foundation under Grant No. AST-1613472 and by the Florida Space Grant Consortium. L.G. acknowledges support from the FINCA visitor programme. The research work at the Physical Research Laboratory is funded by the Department of Space, Government of India. Facility: Magellan: Baade(FIRE).The enigmatic near-infrared transient VVV-WIT-06 underwent a large-amplitude eruption of unclear origin in 2013 July. Based on its light curve properties and late-time post-outburst spectra, various possibilities have been proposed in the literature for the origin of the object, namely a Type I supernova, a classical nova (CN), or a violent stellar merger event. We show that, of these possibilities, an origin in a CN outburst convincingly explains the observed properties of VVV-WIT-06. We estimate that the absolute K-band magnitude of the nova at maximum was M k = -8.2 ±0.5, its distance d = 13.35 ±2.18 kpc, and the extinction A v = 15.0 ±0.55 mag. © 2018. The American Astronomical Society. All rights reserved.https://iopscience.iop.org/article/10.3847/1538-4357/aae5d
Axial Symmetry and Rotation in the SiO Maser Shell of IK Tauri
We observed v=1, J=1-0 43-GHz SiO maser emission toward the Mira variable IK
Tauri (IK Tau) using the Very Long Baseline Array (VLBA). The images resulting
from these observations show that SiO masers form a highly elliptical ring of
emission approximately 58 x 32 mas with an axial ratio of 1.8:1. The major axis
of this elliptical distribution is oriented at position angle of ~59 deg. The
line-of-sight velocity structure of the SiO masers has an apparent axis of
symmetry consistent with the elongation axis of the maser distribution.
Relative to the assumed stellar velocity of 35 km/s, the blue- and red-shifted
masers were found to lie to the northwest and southeast of this symmetry axis
respectively. This velocity structure suggests a NW-SE rotation of the SiO
maser shell with an equatorial velocity, which we determine to be ~3.6 km/s.
Such a NW-SE rotation is in agreement with a circumstellar envelope geometry
invoked to explain previous water and OH maser observations. In this geometry,
water and OH masers are preferentially created in a region of enhanced density
along the NE-SW equator orthogonal to the rotation/polar axis suggested by the
SiO maser velocities.Comment: 17 Pages, 4 figures (2 color); accepted for publication in Ap
A Modern Ethernet Data Acquisition Architecture for Fermilab Beam Instrumentation
The Fermilab Accelerator Division, Instrumentation Department is adopting an
open-source framework to replace our embedded VME-based data acquisition
systems. Utilizing an iterative methodology, we first moved to embedded Linux,
removing the need for VxWorks. Next, we adopted Ethernet on each data
acquisition module eliminating the need for the VME backplane in addition to
communicating with a rack mount server. Development of DDCP (Distributed Data
Communications Protocol), allowed for an abstraction between the firmware and
software layers. Each data acquisition module was adapted to read out using 1
GbE and aggregated at a switch which up linked to a 10 GbE network. Current
development includes scaling the system to aggregate more modules, to increase
bandwidth to support multiple systems and to adopt MicroTCA as a crate
technology. The architecture was utilized on various beamlines around the
Fermilab complex including PIP2IT, FAST/IOTA and the Muon Delivery Ring. In
summary, we were able to develop a data acquisition framework which
incrementally replaces VxWorks & VME hardware as well as increases our total
bandwidth to 10 Gbit/s using off the shelf Ethernet technology
The ALTO project at IPN Orsay
In order to probe neutron rich radioactive noble gases produced by
photo-fission, a PARRNe1 experiment (Production d'Atomes Radioactifs Riches en
Neutrons) has been carried out at CERN. The incident electron beam of 50 MeV
was delivered by the LIL machine: LEP Injector Linac. The experiment allowed to
compare under the same conditions two production methods of radioactive noble
gases: fission induced by fast neutrons and photo-fission. The obtained results
show that the use of the electrons is a promising mode to get intense neutron
rich ion beams. Thereafter, the success of this photo-fission experiment, a
conceptual design for the installation at IPN Orsay of a 50 MeV electron
accelerator close to the PARRNe-2 device has been worked out: ALTO Project.
This work has started within a collaboration between IPNO, LAL and CERN groups.Comment: 14 pages, pdf file, International School-Seminar on Heavy-Ion Physics
7 (2002
VLBI study of water maser emission in the Seyfert 2 galaxy NGC5793. I: Imaging blueshifted emission and the parsec-scale jet
We present the first result of VLBI observations of the blueshifted water
maser emission from the type 2 Seyfert galaxy NGC5793, which we combine with
new and previous VLBI observations of continuum emission at 1.7, 5.0, 8.4, 15,
and 22 GHz. Maser emission was detected earlier in single-dish observations and
found to have both red- and blueshifted features relative to the systemic
velocity. We could image only the blueshifted emission, which is located 3.6 pc
southwest of the 22 GHz continuum peak. The blueshifted emission was found to
originate in two clusters that are separated by 0.7 milliarcsecond (0.16 pc).
No compact continuum emission was found within 3.6 pc of the maser spot. A
compact continuum source showing a marginally inverted spectrum between 1.7 and
5.0 GHz was found 4.2 pc southwest of the maser position. The spectral turnover
might be due to synchrotron self-absorption caused by a shock in the jet owing
to collision with dense gas, or it might be due to free-free absorption in an
ionized screen possibly the inner part of a disk, foreground to the jet.
The water maser may be part of a maser disk. If so, it would be rotating in
the opposite sense to the highly inclined galactic disk observed in CO
emission. We estimate a binding mass within 1 pc of the presumed nucleus to be
on the order of 10^7 Msun. Alternatively, the maser emission could result from
the amplification of a radio jet by foreground circumnuclear molecular gas. In
this case, the high blueshift of the maser emission might mean that the masing
region is moving outward away from the molecular gas surrounding an active
nucleus.Comment: 20 pages, 6 figures, to appear in ApJ, Oct. 200
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