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Wideband precision analog telemetry link using digital techniques
A highly linear Wideband Analog Fiber Optic Link is described which samples at a 1 MHz rate with 10-bit accuracy and transmits and receives by means of a high speed PDM code. Aliasing and sampling effects are fully suppressed and a nearly Gaussian pulse response is attained with a 2 ..mu..sec risetime. Analog signals are recovered with very low distortion and d.c. drift and a S/N ratio of better than 52 db
Maxwell's theory on a post-Riemannian spacetime and the equivalence principle
The form of Maxwell's theory is well known in the framework of general
relativity, a fact that is related to the applicability of the principle of
equivalence to electromagnetic phenomena. We pose the question whether this
form changes if torsion and/or nonmetricity fields are allowed for in
spacetime. Starting from the conservation laws of electric charge and magnetic
flux, we recognize that the Maxwell equations themselves remain the same, but
the constitutive law must depend on the metric and, additionally, may depend on
quantities related to torsion and/or nonmetricity. We illustrate our results by
putting an electric charge on top of a spherically symmetric exact solution of
the metric-affine gauge theory of gravity (comprising torsion and
nonmetricity). All this is compared to the recent results of Vandyck.Comment: 9 pages, REVTeX, no figures; minor changes, version to be published
in Class. Quantum Gra
Adverse events in radiation oncology: A case series from wake up safe, the pediatric anesthesia quality improvement initiative
BackgroundRadiation therapy in pediatric patients often requires anesthesia and poses environmental challenges. Monitoring must be done remotely to limit radiation exposure to the provider. Airway access can be limited by masks or frames. Care is often delivered in relatively inaccessible locations in the hospital. While individual institutions have reported their outcomes, this case series aims to review a multicenter registry of significant adverse events and make recommendations for improved care.MethodsWake Up Safe: The Pediatric Quality Improvement Initiative maintains a multisite, voluntary registry of pediatric perianesthetic significant adverse events. This was queried for reports from radiation oncology from January 1, 2010 to May 10, 2018. The database contained 3,379 significant adverse events from approximately 3.3 million anesthetics. All 33 institutions submitted data on a standardized form to a central data repository (Axio Research, Seattle Washington). Prior to each significant adverse events case submission, three anesthesiologists who were not involved in the event analyzed the event using a standardized root cause analysis method to identify the causal or contributing factor(s).ResultsSix significant adverse events were identified. In three, incorrect programming of a propofol infusion resulted in overdose. In case one, the 3â yearâ old female became hypotensive, requiring vasopressors and volume resuscitation. In the second, the 2â yearâ old female experienced airway obstruction and apnea requiring chin lift. In case three, the child suffered no consequences despite a noted overdose of propofol infusion. In case four, a 2â yearâ old female with recent respiratory infection suffered laryngospasm during an unmonitored transport to the recovery area. She developed profound oxygen desaturation with bradycardia treated with succinylcholine and chest compressions. In case five, a 6â yearâ old former premature child suffered laryngospasm at the conclusion of mask creation under general anesthesia with a laryngeal mask airway. The radiation mask delayed recognition of copious secretions. Finally, in case six, a 6â yearâ old undergoing stereotactic radiosurgery in a head halo suffered bronchospasm and unintended extubation during therapy which required multiple attempts at reintubation by multiple providers ultimately requiring cancellation of the treatment and transport to the intensive care unit.ConclusionThere were few radiation oncology significant adverse events, but analysis has led to the identification of several specific opportunities for improvement in pediatric anesthesia for radiation oncology.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/148238/1/pan13567_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/148238/2/pan13567.pd
On the Symmetries of the Edgar-Ludwig Metric
The conformal Killing equations for the most general (non-plane wave)
conformally flat pure radiation field are solved to find the conformal Killing
vectors. As expected fifteen independent conformal Killing vectors exist, but
in general the metric admits no Killing or homothetic vectors. However for
certain special cases a one-dimensional group of homotheties or motions may
exist and in one very special case, overlooked by previous investigators, a
two-dimensional homethety group exists. No higher dimensional groups of motions
or homotheties are admitted by these metrics.Comment: Plain TeX, 7 pages, No figure
ELF3 controls thermoresponsive growth in Arabidopsis
Plant development is highly responsive to ambient temperature, and this trait has been linked to the ability of plants to adapt to climate change [1]. The mechanisms by which natural populations modulate their thermoresponsiveness are not known [2]. To address this, we surveyed Arabidopsis accessions for variation in thermal responsiveness of elongation growth and mapped the corresponding loci. We find that the transcriptional regulator EARLY FLOWERING3 (ELF3) controls elongation growth in response to temperature. Through a combination of modeling and experiments, we show that high temperature relieves the gating of growth at night, highlighting the importance of temperature-dependent repressors of growth. ELF3 gating of transcriptional targets responds rapidly and reversibly to changes in temperature. We show that the binding of ELF3 to target promoters is temperature dependent, suggesting a mechanism where temperature directly controls ELF3 activity
Poincare gauge theory of gravity: Friedman cosmology with even and odd parity modes. Analytic part
We propose a cosmological model in the framework of the Poincar\'e gauge
theory of gravity (PG). The gravitational Lagrangian is quadratic in curvature
and torsion. In our specific model, the Lagrangian contains (i) the curvature
scalar and the curvature pseudo-scalar linearly and quadratically
(including an term) and (ii) pieces quadratic in the torsion {\it vector}
and the torsion {\it axial} vector (including a term). We show generally that in quadratic PG models we have nearly
the same number of parity conserving terms (`world') and of parity violating
terms (`shadow world'). This offers new perspectives in cosmology for the
coupling of gravity to matter and antimatter. Our specific model generalizes
the fairly realistic `torsion cosmologies' of Shie-Nester-Yo (2008) and Chen et
al.\ (2009). With a Friedman type ansatz for an orthonormal coframe and a
Lorentz connection, we derive the two field equations of PG in an explicit form
and discuss their general structure in detail. In particular, the second field
equation can be reduced to first order ordinary differential equations for the
curvature pieces and . Including these along with certain
relations obtained from the first field equation and curvature definitions, we
present a first order system of equations suitable for numerical evaluation.
This is deferred to the second, numerical part of this paper.Comment: Latex computerscript, 25 pages; mistakes corrected, references added,
notation and title slightly changed; accepted by Phys. Rev.
Pleba\'nski-Demia\'nski-like solutions in metric-affine gravity
We consider a (non--Riemannian) metric--affine gravity theory, in particular
its nonmetricity--torsion sector ``isomorphic'' to the Einstein--Maxwell
theory. We map certain Einstein--Maxwell electrovacuum solutions to it, namely
the Pleba\'nski--Demia\'nski class of Petrov type D metrics.Comment: 12 pages of a LaTeX-fil
The appropriation of hegemonic masculinity within selected research on men's health
Connell's hegemonic masculinity thesis (HMT) has occupied a relatively dominant position within contemporary research exploring the lives of men. Messerschmidt has conducted a review of recent literature that purports to use HMT, he describes in detail some of the ways Connell's work has been appropriated. Taking Messerschmidt's lead, this paper explores a small selection of men's health research that employ HMT as a central organising theme. Such a narrow focus and limited sample enables the theoretical, conceptual and empirical contributions of engagements with Connell's work to be critically explored in detail. This paper provides colleagues with clear examples of ways in which reified and reductive account of masculinity, are still being reproduced in contemporary analyses of men's lives. In calling for researchers to critically reflect upon their usage of Connell's thesis in more detail, my aim is to increase the subtlety and sophistication of such works. A further hope is that by highlighting specific examples of the need to appraise the relevance and adequacy of HMT as a conceptual frame of lived experiences, we might encourage researchers to access the multitude of different theoretical positions that speak to the lives of men
An axisymmetric evolution code for the Einstein equations on hyperboloidal slices
We present the first stable dynamical numerical evolutions of the Einstein
equations in terms of a conformally rescaled metric on hyperboloidal
hypersurfaces extending to future null infinity. Axisymmetry is imposed in
order to reduce the computational cost. The formulation is based on an earlier
axisymmetric evolution scheme, adapted to time slices of constant mean
curvature. Ideas from a previous study by Moncrief and the author are applied
in order to regularize the formally singular evolution equations at future null
infinity. Long-term stable and convergent evolutions of Schwarzschild spacetime
are obtained, including a gravitational perturbation. The Bondi news function
is evaluated at future null infinity.Comment: 21 pages, 4 figures. Minor additions, updated to agree with journal
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