237 research outputs found
Accuracy of binary black hole waveform models for aligned-spin binaries
Coalescing binary black holes are among the primary science targets for
second generation ground-based gravitational wave (GW) detectors. Reliable GW
models are central to detection of such systems and subsequent parameter
estimation. This paper performs a comprehensive analysis of the accuracy of
recent waveform models for binary black holes with aligned spins, utilizing a
new set of high-accuracy numerical relativity simulations. Our analysis
covers comparable mass binaries (), and samples
independently both black hole spins up to dimensionless spin-magnitude of
for equal-mass binaries and for unequal mass binaries. Furthermore, we
focus on the high-mass regime (total mass ). The two most
recent waveform models considered (PhenomD and SEOBNRv2) both perform very well
for signal detection, losing less than 0.5\% of the recoverable signal-to-noise
ratio , except that SEOBNRv2's efficiency drops mildly for both black
hole spins aligned with large magnitude. For parameter estimation, modeling
inaccuracies of SEOBNRv2 are found to be smaller than systematic uncertainties
for moderately strong GW events up to roughly . PhenomD's
modeling errors are found to be smaller than SEOBNRv2's, and are generally
irrelevant for . Both models' accuracy deteriorates with
increased mass-ratio, and when at least one black hole spin is large and
aligned. The SEOBNRv2 model shows a pronounced disagreement with the numerical
relativity simulation in the merger phase, for unequal masses and
simultaneously both black hole spins very large and aligned. Two older waveform
models (PhenomC and SEOBNRv1) are found to be distinctly less accurate than the
more recent PhenomD and SEOBNRv2 models. Finally, we quantify the bias expected
from all GW models during parameter estimation for recovery of binary's masses
and spins.Comment: 24 pages, 15 figures, minor change
On the accuracy and precision of numerical waveforms: Effect of waveform extraction methodology
We present a new set of 95 numerical relativity simulations of non-precessing
binary black holes (BBHs). The simulations sample comprehensively both
black-hole spins up to spin magnitude of 0.9, and cover mass ratios 1 to 3. The
simulations cover on average 24 inspiral orbits, plus merger and ringdown, with
low initial orbital eccentricities . A subset of the simulations
extends the coverage of non-spinning BBHs up to mass ratio .
Gravitational waveforms at asymptotic infinity are computed with two
independent techniques, extrapolation, and Cauchy characteristic extraction. An
error analysis based on noise-weighted inner products is performed. We find
that numerical truncation error, error due to gravitational wave extraction,
and errors due to the finite length of the numerical waveforms are of similar
magnitude, with gravitational wave extraction errors somewhat dominating at
noise-weighted mismatches of . This set of waveforms will
serve to validate and improve aligned-spin waveform models for gravitational
wave science.Comment: 22 pages, 9 figure
The impact of Covid-19 restrictions and changes to takeaway regulations in England on consumers’ intake of, and method of accessing out-of-home foods:a longitudinal, mixed-methods study
COVID-19 restrictions significantly impacted the operations of Fast Food and Full Service retail-ers. Full Service retailers were permitted to operate as takeaway outlets without needing to seek formal changes in planning permissions. We conducted a study to determine consumers’ intake of, and mode of accessing foods from Fast Food and Full Service retailers during various Covid-19 restrictions and changes to takeaway/delivery regulations, and their experiences of this. Methods: We conducted a longitudinal, mixed-methods study comprising three surveys examining intake frequency and modes of accessing retailers, and two rounds of qualitative focus groups exploring related experiences. Data were collected from May 2021 – March 2022. Participants were adults living in Northern England (n = 701 at T1); a sub-sample participated in focus groups (n = 22). Intake data were presented descriptively; an ordered logit regression explored factors associated with intake frequency. Focus group data were analysed using Framework Analysis. Results: Mean weekly intake frequency from Fast Food retailers at T1, T2 and T3 was 0.96 (SD 1.05), 1.08 (SD 1.16) and 1.06 times (SD 1.12), respectively. For Full Service retailers, this was 0.36 (SD 0.69), 0.75 (1.06) and 0.71 (SD 0.99) times, respectively. Food access issues (OR (SE): T1 = 1.65 (0.40), T2 = 2.60 (0.66), T = 2.1 (0.62)) and obesity (T1 = 1.61 (0.31), T2 = 2.21 (0.46), T3 = 1.85 (0.42)) were pos-itively associated with intake from Fast Food, but not Full Service retailers. Delivery services were commonly used to access Fast Food (30–34% participants), but not Full Service retailers (6-10% participants). As Covid-19 restrictions eased, participants were eager to socialise on-premises at Full Service retailers. Conclusions: Takeaway/delivery services were seldom used to access Full Service retailers; use of delivery services to access Fast Food was high. Policy-makers must rec-ognise delivery services as a growing part of the food environment, and the challenges they pose to planning policies for obesity prevention. Keywords: Food delivery service
TESLA-X: An effective method to search for sub-threshold lensed gravitational waves with a targeted population model
Strong gravitational lensing can produce copies of gravitational-wave signals
from the same source with the same waveform morphologies but different
amplitudes and arrival times. Some of these strongly-lensed gravitational-wave
signals can be demagnified and become sub-threshold. We present TESLA-X, an
enhanced approach to the original GstLAL-based TargetEd Subthreshold Lensing
seArch (TESLA) method, for improving the detection efficiency of these
potential sub-threshold lensed signals. TESLA-X utilizes lensed injections to
generate a targeted population model and a targeted template bank. We compare
the performance of a full template bank search, TESLA, and TESLA-X methods via
a simulation campaign, and demonstrate the performance of TESLA-X in recovering
lensed injections, particularly targeting a mock event. Our results show that
the TESLA-X method achieves a maximum of higher search sensitivity
compared to the TESLA method within the sub-threshold regime, presenting a step
towards detecting the first lensed gravitational wave. TESLA-X will be employed
for the LIGO-Virgo-KAGRA's collaboration-wide analysis to search for lensing
signatures in the fourth observing run
Characterization of mouse orofacial pain and the effects of lesioning TRPV1-expressing neurons on operant behavior
<p>Abstract</p> <p>Background</p> <p>Rodent models of orofacial pain typically use methods adapted from manipulations to hind paw; however, limitations of these models include animal restraint and subjective assessments of behavior by the experimenter. In contrast to these methods, assessment of operant responses to painful stimuli has been shown to overcome these limitations and expand the breadth of interpretation of the behavioral responses. In the current study, we used an operant model based on a reward-conflict paradigm to assess nociceptive responses in three strains of mice (SKH1-Hr<sup>hr</sup>, C57BL/6J, TRPV1 knockout). We previously validated this operant model in rats and hypothesized in this study that wild-type mice would demonstrate a similar thermal stimulus-dependent response and similar operant pain behaviors. Additionally, we evaluated the effects on operant behaviors of mice manipulated genetically (e.g., TRPV1 k.o.) or pharmacologically with resiniferatoxin (RTX), a lesioning agent for TRPV1-expressing neurons. During the reward-conflict task, mice accessed a sweetened milk reward solution by voluntarily position their face against a neutral or heated thermode (37–55°C).</p> <p>Results</p> <p>As the temperature of the thermal stimulus became noxiously hot, reward licking events in SKH1-Hr<sup>hr </sup>and C57BL/6J mice declined while licking events in TRPV1 k.o. mice were insensitive to noxious heat within the activation range of TRPV1 (37–52°C). All three strains displayed nocifensive behaviors at 55°C, as indicated by a significant decrease in reward licking events. Induction of neurogenic inflammation by topical application of capsaicin reduced licking events in SKH1-Hr<sup>hr </sup>mice, and morphine rescued this response. Again, these results parallel what we previously documented using rats in this operant system. Following intracisternal treatment with RTX, C57BL/6J mice demonstrated a block of noxious heat at both 48 and 55°C. RTX-treated TRPV1 k.o. mice and all vehicle-treated mice displayed similar reward licking events as compared to the pre-treatment baseline levels. Both TRPV1 k.o. and RTX-treated C57BL/6J had complete abolishment of eye-wipe responses following corneal application of capsaicin.</p> <p>Conclusion</p> <p>Taken together, these results indicate the benefits of using the operant test system to investigate pain sensitivity in mice. This ability provides an essential step in the development of new treatments for patients suffering from orofacial pain disorders.</p
The GstLAL Search Analysis Methods for Compact Binary Mergers in Advanced LIGO's Second and Advanced Virgo's First Observing Runs
After their successful first observing run (September 12, 2015 - January 12,
2016), the Advanced LIGO detectors were upgraded to increase their sensitivity
for the second observing run (November 30, 2016 - August 26, 2017). The
Advanced Virgo detector joined the second observing run on August 1, 2017. We
discuss the updates that happened during this period in the GstLAL-based
inspiral pipeline, which is used to detect gravitational waves from the
coalescence of compact binaries both in low latency and an offline
configuration. These updates include deployment of a zero-latency whitening
filter to reduce the over-all latency of the pipeline by up to 32 seconds,
incorporation of the Virgo data stream in the analysis, introduction of a
single-detector search to analyze data from the periods when only one of the
detectors is running, addition of new parameters to the likelihood ratio
ranking statistic, increase in the parameter space of the search, and
introduction of a template mass-dependent glitch-excision thresholding method.Comment: 12 pages, 7 figures, to be submitted to Phys. Rev. D, comments
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The GstLAL template bank for spinning compact binary mergers in the second observation run of Advanced LIGO and Virgo
We describe the methods used to construct the aligned-spin template bank of
gravitational waveforms used by the GstLAL-based inspiral pipeline to analyze
data from the second observing run of Advanced LIGO and Virgo. The bank expands
upon the parameter space covered during the first observing run, including
coverage for merging compact binary systems with total mass between 2
and 400 and mass ratios between 1 and
97.989. Thus the systems targeted include merging neutron star-neutron star
systems, neutron star-black hole binaries, and black hole-black hole binaries
expanding into the intermediate-mass range. Component masses less than 2
have allowed (anti-)aligned spins between while
component masses greater than 2 have allowed
(anti-)aligned between . The bank placement technique combines a
stochastic method with a new grid-bank method to better isolate noisy
templates, resulting in a total of 677,000 templates.Comment: 9 pages, 13 figure
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