A sparse representation of gravitational waves from precessing compact binaries

Many relevant applications in gravitational wave physics share a significant common problem: the seven-dimensional parameter space of gravitational waveforms from precessing compact binary inspirals and coalescences is large enough to prohibit covering the space of waveforms with sufficient density. We find that by using the reduced basis method together with a parametrization of waveforms based on their phase and precession, we can construct ultra-compact yet high-accuracy representations of this large space. As a demonstration, we show that less than $100$ judiciously chosen precessing inspiral waveforms are needed for $200$ cycles, mass ratios from $1$ to $10$ and spin magnitudes $\le 0.9$. In fact, using only the first $10$ reduced basis waveforms yields a maximum mismatch of $0.016$ over the whole range of considered parameters. We test whether the parameters selected from the inspiral regime result in an accurate reduced basis when including merger and ringdown; we find that this is indeed the case in the context of a non-precessing effective-one-body model. This evidence suggests that as few as $\sim 100$ numerical simulations of binary black hole coalescences may accurately represent the seven-dimensional parameter space of precession waveforms for the considered ranges.Comment: 5 pages, 3 figures. The parameters selected for the basis of precessing waveforms can be found in the source file

Fast and accurate prediction of numerical relativity waveforms from binary black hole coalescences using surrogate models

Simulating a binary black hole (BBH) coalescence by solving Einstein's equations is computationally expensive, requiring days to months of supercomputing time. Using reduced order modeling techniques, we construct an accurate surrogate model, which is evaluated in a millisecond to a second, for numerical relativity (NR) waveforms from non-spinning BBH coalescences with mass ratios in $[1, 10]$ and durations corresponding to about $15$ orbits before merger. We assess the model's uncertainty and show that our modeling strategy predicts NR waveforms {\em not} used for the surrogate's training with errors nearly as small as the numerical error of the NR code. Our model includes all spherical-harmonic ${}_{-2}Y_{\ell m}$ waveform modes resolved by the NR code up to $\ell=8.$ We compare our surrogate model to Effective One Body waveforms from $50$-$300 M_\odot$ for advanced LIGO detectors and find that the surrogate is always more faithful (by at least an order of magnitude in most cases).Comment: Updated to published version, which includes a section comparing the surrogate and effective-one-body models. The surrogate is publicly available for download at http://www.black-holes.org/surrogates/ . 6 pages, 6 figure

Nursing Implications in the ECMO Patient

Effective care and positive outcomes of the extracorporeal membrane oxygenation (ECMO) patient necessitate optimal interdisciplinary management from the healthcare team, including expert care from specially trained registered nurses (RNs). It is incumbent upon the RN caring for the ECMO patient to excel in both time management and assessment skills, as this population often demands care delivery at the pinnacle of intensive care unit (ICU) acuity. Astute and nuanced monitoring of neurological status, bleeding risk with potential (often massive) transfusions, poor hemodynamics, and integrity of the ECMO pump itself are only the few specialized areas of focus that must share priority with traditional nursing considerations involving the critically ill, such as prevention of pressure injuries and bloodstream infections. These high-intensity medical foci must be balanced with ethical considerations, as the ultimate goal of returning the patient to their normal life is not always possible. These demands highlight the dynamic proficiency of the RN caring for the ECMO patient. The following chapter will highlight the importance of specialized nursing care in the critically ill patient supported with ECMO

KINEMATIC ANALYSIS OF SURFACE AND UNDERWATER FIN-SWIMMING

The aim of the study was to perform a comparative kinematic analysis of surface and underwater fin-swimming. Results of the experiments were obtained in terms of motion as well as maximum and minimum differences between the technique of surface and underwater fin-swimming

Balancing Justice and Mercy: Redemptive Ways of Dealing With Adolescent Substance Abuse

This article will briefly describe the range of policies relating to drug or substance possession and use that are found in the boarding and day academies of the Lake Union Conference (in the North American Division). Next, we will deal with the areas of screening, discipline, and referral to appropriate services. Finally, using case examples of two very different student experiences with illegal substances, we will offer some policy recommendations for dealing redemptively with substance abuse by students