19 research outputs found
Acoustic field coherence in four-dimensionally variable shallow water environments : estimation using co-located horizontal and vertical line arrays
Underwater Acoustic Measurements (UAM) 2nd International Conference & Exhibition on "Underwater Acoustic Measurements: Technologies & Results," 25-29 June 2007, Heraklion, Crete, Greece.The implementation of two- and three-dimensional acoustic receiver arrays is
challenging in the ocean environment. Fixed geometry and connectivity can only be built
and maintained at great expense. However, such ideal arrays can be very powerful for
signal detection, classification, and tracking, although many of the signal-processing
methods employed are subject to constraints of acoustic field temporal and spatial
coherence. Thus, understanding the processes at work determining coherence is essential
because system effectiveness may then be predictable from environmental parameter
input. To study acoustic fields and coherence over finite aperture, the research
community has recently taken steps to enable routine use of co-located horizontal and
vertical line arrays, typically arranged in the shape of the Roman letter L (or Greek ),
with the horizontal leg on the seafloor. This is a small subset of all possible geometries,
but it enables measurements of acoustic field coherence not possible with single line
arrays. Here, new L-array measurements made in the SW06 field program are used to
measure coherence and test coherence predictions via joint analysis of vertical and
horizontal line array receptions. Impulsive mode arrivals (including mode multipath)
from fixed sources will be estimated using the vertical array. Signals on the horizontal
array, which is neither broadside nor endfire, will be compared with signals synthesized
using the mode arrivals to estimate azimuthal decorrelation effects. Results can be
compared with coherence estimates from computational and theoretical studies
Elastic Pekeris waveguide normal mode solution comparisons against laboratory data
Following the derivation presented by Press and Ewing [Geophysics 15, 426-446 (1950)], a normal mode solution for the Pekeris waveguide problem with an elastic bottom is outlined. The analytic solution is benchmarked against data collected in an experiment performed at the Naval Research Laboratory [Collis et al., J. Acoust. Soc. Am. 122, 1987-1993 (2007)]. Comparisons reveal a close match between the analytic solution and experimental data. Results are strongly dependent on the accuracy of the horizontal wavenumbers for the modes, and horizontal wavenumber spectra are compared against those from the experimental data. (C) 2012 Acoustical Society of AmericaNational Science Foundation Division of Graduate Education [DGE-0638719
Observed limiting cases of horizontal field coherence and array performance in a time-varying internal wavefield
Author Posting. © Acoustical Society of America, 2008. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 124 (2008): EL97-EL103, doi:10.1121/1.2947630.Using a moored source and horizontal/vertical line array combination, horizontal coherence properties of high signal to noise ratio (>=20 dB) 100â1600 Hz signals have been measured. Internal waves in the area of the measurement created moving episodic sound-speed anomaly structures, influencing coherence length. Measured horizontal coherence scales for 100 Hz ranged from 5 to 20 acoustic wavelengths, and were inversely related to the sound-speed anomaly strength. Horizontal field properties were compared with fields computed using modal decompositions of the vertical signals. The comparison allows azimuthal field coherence properties to be studied apart from normal-mode interference effects.This work was funded by grants to Boston University and the Woods Hole Oceanographic
Institution from the Ocean Acoustics Program at the U.S. Office of Naval Research,
including an ONR Postdoctoral Fellowship award to the first author
A three-dimensional parabolic equation model of sound propagation using higher-order operator splitting and Padé approximants
Author Posting. © Acoustical Society of America, 2012. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 132 (2012): EL364-EL370, doi:10.1121/1.4754421.An alternating direction implicit (ADI) three-dimensional fluid parabolic equation solution method with enhanced accuracy is presented. The method uses a square-root Helmholtz operator splitting algorithm that retains cross-multiplied operator terms that have been previously neglected. With these higher-order cross terms, the valid angular range of the parabolic equation solution is improved. The method is tested for accuracy against an image solution in an idealized wedge problem. Computational efficiency improvements resulting from the ADI discretization are also discussed.This work was sponsored by the Office of Naval Research under Grant Nos. N00014-10-1-0040 and N00014-11-1-0701
Horizontal coherence of low-frequency fixed-path sound in a continental shelf region with internal-wave activity
Author Posting. © Acoustical Society of America, 2012. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 131 (2012): 1782-1797, doi:10.1121/1.3666003.Sound at 85 to 450 Hz propagating in approximately 80-m depth water from fixed sources to a joint horizontal/vertical line array (HLA/VLA) is analyzed. The data are from a continental shelf area east of Delaware Bay (USA) populated with tidally generated long- and short-wavelength internal waves. Sound paths are 19 km in the along-shore (along internal-wave crest) direction and 30 km in the cross-shore direction. Spatial statistics of HLA arrivals are computed as functions of beam steering angle and time. These include array gain, horizontally lagged spatial correlation function, and coherent beam power. These quantities vary widely in magnitude, and vary over a broad range of time scales. For example, correlation scale can change rapidly from forty to five wavelengths, and correlation-scale behavior is anisotropic. In addition, the vertical array can be used to predict correlation expected for adiabatic propagation with cylindrical symmetry, forming a benchmark. Observed variations are in concert with internal-wave activity. Temporal variations of three coherence measures, horizontal correlation length, array gain, and ratio of actual correlation length to predicted adiabatic-mode correlation length, are very strong, varying by almost a factor of ten as internal waves pass.This work was supported by Office of Naval Research
(ONR) Grants Nos. N00014-05-1-0482 and N00014-11-1-
0194 to T.F.D., ONR Grant No. N00014-04-1-0146 to
J.F.L., and an ONR Ocean Acoustics Postdoctoral Fellowship
awarded to J.M.C. under Professor William Carey at
Boston University
Patient-reported outcomes in integrated health and social care:A scoping review
Background: Patient-reported outcomes (PROs) have potential to support integrated health and social care research and practice; however, evidence of their utilisation has not been synthesised. Objective: To identify PRO measures utilised in integrated care and adult social care research and practice and to chart the evidence of implementation factors influencing their uptake. Design: Scoping review of peer-reviewed literature. Data sources: Six databases (01 January 2010 to 19 May 2023). Study selection: Articles reporting PRO use with adults (18+ years) in integrated care or social care settings. Review methods: We screened articles against pre-specified eligibility criteria; 36 studies (23%) were extracted in duplicate for verification. We summarised the data using thematic analysis and descriptive statistics. Results: We identified 159 articles reporting on 216 PRO measures deployed in a social care or integrated care setting. Most articles used PRO measures as research tools. Eight (5.0%) articles used PRO measures as an intervention. Articles focused on community-dwelling participants (35.8%) or long-term care home residents (23.9%), with three articles (1.9%) focussing on integrated care settings. Stakeholders viewed PROs as feasible and acceptable, with benefits for care planning, health and wellbeing monitoring as well as quality assurance. Patient-reported outcome measure selection, administration and PRO data management were perceived implementation barriers. Conclusion: This scoping review showed increasing utilisation of PROs in adult social care and integrated care. Further research is needed to optimise PROs for care planning, design effective training resources and develop policies and service delivery models that prioritise secure, ethical management of PRO data
Patient-reported outcomes in integrated health and social care:A scoping review
Background: Patient-reported outcomes (PROs) have potential to support integrated health and social care research and practice; however, evidence of their utilisation has not been synthesised. Objective: To identify PRO measures utilised in integrated care and adult social care research and practice and to chart the evidence of implementation factors influencing their uptake. Design: Scoping review of peer-reviewed literature. Data sources: Six databases (01 January 2010 to 19 May 2023). Study selection: Articles reporting PRO use with adults (18+ years) in integrated care or social care settings. Review methods: We screened articles against pre-specified eligibility criteria; 36 studies (23%) were extracted in duplicate for verification. We summarised the data using thematic analysis and descriptive statistics. Results: We identified 159 articles reporting on 216 PRO measures deployed in a social care or integrated care setting. Most articles used PRO measures as research tools. Eight (5.0%) articles used PRO measures as an intervention. Articles focused on community-dwelling participants (35.8%) or long-term care home residents (23.9%), with three articles (1.9%) focussing on integrated care settings. Stakeholders viewed PROs as feasible and acceptable, with benefits for care planning, health and wellbeing monitoring as well as quality assurance. Patient-reported outcome measure selection, administration and PRO data management were perceived implementation barriers. Conclusion: This scoping review showed increasing utilisation of PROs in adult social care and integrated care. Further research is needed to optimise PROs for care planning, design effective training resources and develop policies and service delivery models that prioritise secure, ethical management of PRO data
Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19
IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19.
Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19.
DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 nonâcritically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022).
INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (nâ=â257), ARB (nâ=â248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; nâ=â10), or no RAS inhibitor (control; nâ=â264) for up to 10 days.
MAIN OUTCOMES AND MEASURES The primary outcome was organ supportâfree days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes.
RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ supportâfree days among critically ill patients was 10 (â1 to 16) in the ACE inhibitor group (nâ=â231), 8 (â1 to 17) in the ARB group (nâ=â217), and 12 (0 to 17) in the control group (nâ=â231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ supportâfree days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively).
CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes.
TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570