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48-year-old with Coronavirus Disease 2019
Case Presentation: A 48-year-old male who presented with signs and symptoms suggestive of an upper respiratory infection was seen at an urgent care, he had a negative chest radiograph and was discharged. With no other cases of coronavirus disease 2019 (COVID-19) in the state, the patient presented to the emergency department two days later with worsening shortness of breath.Discussion: There are a variety of findings on both chest radiograph and computed tomography of the chest that suggests COVID-19
Enhanced monitoring of the preterm infant during stabilization in the delivery room
Monitoring of preterm infants in the delivery room (DR) remains limited. Current guidelines suggest that pulse oximetry should be available for all preterm infant deliveries, and that if intubated a colorimetric carbon dioxide detector should provide verification of correct endotracheal tube placement. These two methods of assessment represent the extent of objective monitoring of the newborn commonly performed in the DR. Monitoring non-invasive ventilation effectiveness (either by capnography or respiratory function monitoring) and cerebral oxygenation (near-infrared spectroscopy) is becoming more common within research settings. In this article, we will review the different modalities available for cardiorespiratory and neuromonitoring in the DR and assess the current evidence base on their feasibility, strengths, and limitations during preterm stabilization
Response: Commentary: Enhanced monitoring of the preterm infant during stabilization in the delivery room
A commentary on: Enhanced Monitoring of the Preterm Infant during Stabilization in the Delivery Room by Hutchon DJ. Front Pediatr (2016) 4:64. doi: 10.3389/fped.2016.0006
Measuring black-hole parameters and testing general relativity using gravitational-wave data from space-based interferometers
Among the expected sources of gravitational waves for the Laser
Interferometer Space Antenna (LISA) is the capture of solar-mass compact stars
by massive black holes residing in galactic centers. We construct a simple
model for such a capture, in which the compact star moves freely on a circular
orbit in the equatorial plane of the massive black hole. We consider the
gravitational waves emitted during the late stages of orbital evolution,
shortly before the orbiting mass reaches the innermost stable circular orbit.
We construct a simple model for the gravitational-wave signal, in which the
phasing of the waves plays the dominant role. The signal's behavior depends on
a number of parameters, including , the mass of the orbiting star, ,
the mass of the central black hole, and , the black hole's angular momentum.
We calculate, using our simplified model, and in the limit of large
signal-to-noise ratio, the accuracy with which these quantities can be
estimated during a gravitational-wave measurement. Our simplified model also
suggests a method for experimentally testing the strong-field predictions of
general relativity.Comment: ReVTeX, 16 pages, 5 postscript figure
Nearly horizon skimming orbits of Kerr black holes
An unusual set of orbits about extreme Kerr black holes resides at the
Boyer-Lindquist radius , the coordinate of the hole's event horizon.
These ``horizon skimming'' orbits have the property that their angular momentum
{\it increases} with inclination angle, opposite to the familiar behavior
one encounters at larger radius. In this paper, I show that this behavior is
characteristic of a larger family of orbits, the ``nearly horizon skimming''
(NHS) orbits. NHS orbits exist in the very strong field of any black hole with
spin a\agt 0.952412M. Their unusual behavior is due to the locking of
particle motion near the event horizon to the hole's spin, and is therefore a
signature of the Kerr metric's extreme strong field. An observational hallmark
of NHS orbits is that a small body spiraling into a Kerr black hole due to
gravitational-wave emission will be driven into orbits of progressively smaller
inclination angle, toward the equator. This is in contrast to the ``normal''
behavior. For circular orbits, the change in inclination is very small, and
unlikely to be of observational importance. I argue that the change in
inclination may be considerably larger when one considers the evolution of
inclined eccentric orbits. If this proves correct, then the gravitational waves
produced by evolution through the NHS regime may constitute a very interesting
and important probe of the strong-field nature of rotating black holes.Comment: 9 pages, 5 figures, accepted for publication in PR
Black Hole Spectroscopy: Testing General Relativity through Gravitational Wave Observations
Assuming that general relativity is the correct theory of gravity in the
strong field limit, can gravitational wave observations distinguish between
black hole and other compact object sources? Alternatively, can gravitational
wave observations provide a test of one of the fundamental predictions of
general relativity? Here we describe a definitive test of the hypothesis that
observations of damped, sinusoidal gravitational waves originated from a black
hole or, alternatively, that nature respects the general relativistic no-hair
theorem. For astrophysical black holes, which have a negligible charge-to-mass
ratio, the black hole quasi-normal mode spectrum is characterized entirely by
the black hole mass and angular momentum and is unique to black holes. In a
different theory of gravity, or if the observed radiation arises from a
different source (e.g., a neutron star, strange matter or boson star), the
spectrum will be inconsistent with that predicted for general relativistic
black holes. We give a statistical characterization of the consistency between
the noisy observation and the theoretical predictions of general relativity,
together with a numerical example.Comment: 19 pages, 7 figure
Gravitational Waves from a Compact Star in a Circular, Inspiral Orbit, in the Equatorial Plane of a Massive, Spinning Black Hole, as Observed by LISA
Results are presented from high-precision computations of the orbital
evolution and emitted gravitational waves for a stellar-mass object spiraling
into a massive black hole in a slowly shrinking, circular, equatorial orbit.
The focus of these computations is inspiral near the innermost stable circular
orbit (isco)---more particularly, on orbits for which the angular velocity
Omega is 0.03 < Omega/Omega_{isco} < 1. The computations are based on the
Teukolsky-Sasaki-Nakamura formalism, and the results are tabulated in a set of
functions that are of order unity and represent relativistic corrections to
low-orbital-velocity formulas. These tables can form a foundation for future
design studies for the LISA space-based gravitational-wave mission. A first
survey of applications to LISA is presented: Signal to noise ratios S/N are
computed and graphed as functions of the time-evolving gravitational-wave
frequency for representative values of the hole's mass M and spin a and the
inspiraling object's mass \mu, with the distance to Earth chosen to be r_o = 1
Gpc. These S/N's show a very strong dependence on the black-hole spin, as well
as on M and \mu. A comparison with predicted event rates shows strong promise
for detecting these waves, but not beyond about 1Gpc if the inspiraling object
is a white dwarf or neutron star. This argues for a modest lowering of LISA's
noise floor. A brief discussion is given of the prospects for extracting
information from the observed wavesComment: Physical Review D, in press; 21 pages, 9 figures, 10 tables it is
present in the RevTeX fil
Improving the biological interfacing capability of Improving the biological interfacing capability of diketopyrrolopyrrole polymers via p-type doping
Polydiketopyrrolopyrrole terthiophene (DPP3T), a high-performing conjugated polymer, holds great potential as active material for bioelectronics. Herein, its surface properties are modulated through p-type doping, thereby enhancing the cell behaviour on top of the doped films
Bounding the mass of the graviton using gravitional-wave observations of inspiralling compact binaries
If gravitation is propagated by a massive field, then the velocity of
gravitational waves (gravitons) will depend upon their frequency and the
effective Newtonian potential will have a Yukawa form. In the case of
inspiralling compact binaries, gravitational waves emitted at low frequency
early in the inspiral will travel slightly slower than those emitted at high
frequency later, modifying the phase evolution of the observed inspiral
gravitational waveform, similar to that caused by post-Newtonian corrections to
quadrupole phasing. Matched filtering of the waveforms can bound such
frequency-dependent variations in propagation speed, and thereby bound the
graviton mass. The bound depends on the mass of the source and on noise
characteristics of the detector, but is independent of the distance to the
source, except for weak cosmological redshift effects. For observations of
stellar-mass compact inspiral using ground-based interferometers of the
LIGO/VIRGO type, the bound on the graviton Compton wavelength is of the order
of km, about double that from solar-system tests of Yukawa
modifications of Newtonian gravity. For observations of super-massive black
hole binary inspiral at cosmological distances using the proposed laser
interferometer space antenna (LISA), the bound can be as large as km. This is three orders of magnitude weaker than model-dependent
bounds from galactic cluster dynamics.Comment: 8 pages, RevTeX, submitted to Phys. Rev.
A Bayesian General Linear Modeling Approach to Cortical Surface fMRI Data Analysis
Cortical surface functional magnetic resonance imaging (cs-fMRI) has recently grown in popularity versus traditional volumetric fMRI. In addition to offering better whole-brain visualization, dimension reduction, removal of extraneous tissue types, and improved alignment of cortical areas across subjects, it is also more compatible with common assumptions of Bayesian spatial models. However, as no spatial Bayesian model has been proposed for cs-fMRI data, most analyses continue to employ the classical general linear model (GLM), a âmassive univariateâ approach. Here, we propose a spatial Bayesian GLM for cs-fMRI, which employs a class of sophisticated spatial processes to model latent activation fields. We make several advances compared with existing spatial Bayesian models for volumetric fMRI. First, we use integrated nested Laplacian approximations, a highly accurate and efficient Bayesian computation technique, rather than variational Bayes. To identify regions of activation, we utilize an excursions set method based on the joint posterior distribution of the latent fields, rather than the marginal distribution at each location. Finally, we propose the first multi-subject spatial Bayesian modeling approach, which addresses a major gap in the existing literature. The methods are very computationally advantageous and are validated through simulation studies and two task fMRI studies from the Human Connectome Project. Supplementary materials for this article, including a standardized description of the materials available for reproducing the work, are available as an online supplement
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