Performance of three hydrophone flow shields in a tidal channel.

Pseudosound caused by turbulent pressure fluctuations in fluid flow past a hydrophone, referred to as flow noise, can mask propagating sounds of interest. Flow shields can mitigate flow noise by reducing non-acoustic pressure fluctuations sensed by a hydrophone. We evaluate the performance of three hydrophone flow shields (two nylon fabrics and an oil-filled enclosure) in a tidal channel with peak current speed of 1.3 m s-1. All three flow shields reduced flow noise without attenuating propagating sound below 20 kHz. The oil-filled enclosure performed best, reducing flow noise by over 30 dB at frequencies below 40 Hz.

Emergency Nurses' Well-Being in Magnet Hospitals and Recommendations for Improvements in Work Environments: A Multicenter Cross-Sectional Observational Study.

INTRODUCTION: This study aimed to determine the well-being outcomes and quality of work environment among emergency nurses compared with inpatient nurses working in Magnet hospitals and identify recommendations in emergency department work environments that hold promise for enhancing emergency nurses' well-being. METHODS: This is a cross-sectional analysis of multicenter survey data collected in 2021 from 11,743 nurses practicing in 60 United States Magnet hospitals. Nurses report on burnout, job dissatisfaction, intent to leave, work environment, and recommendations to improve well-being. RESULTS: Emergency nurses are significantly more likely to report high burnout (P = .04), job dissatisfaction (P < .001), and intent to leave (P < .001) than inpatient nurses working in the same Magnet hospitals. Emergency nurses are significantly more likely to report insufficient staffing (P = .001), an unfavorable work environment (P < .001), and lack confidence that management will act to resolve problems in patient care (P < .001) but did report significantly better working relationships with physicians (P < .001) than their inpatient counterparts. The 2 greatest recommendations to improve well-being included improving nurse staffing (91.4%) and the ability to take uninterrupted breaks (86.7%); the lowest-ranked recommendations were employing more advanced practice providers (25.9%) and appointing a wellness champion (21.2%). DISCUSSION: High burnout and other adverse nurse outcomes are common among emergency nurses in Magnet hospitals. Modifiable features of ED work environments including inadequate nurse staffing, inability of nurses to take uninterrupted breaks, and lack of responsiveness of management to persistent problems in patient care warrant high priority attention by Magnet hospital leaders.

Cognitive impairment is associated with greater preoperative symptoms, worse health-related quality of life, and reduced likelihood of recovery after cervical and lumbar spine surgery.

Background: Cognitive impairment (CI) is associated with prolonged hospital stays and increased complications; however, its role in symptom severity and health-related quality of life (HRQoL) among spine patients is unknown. We determined 1) prevalence of preoperative CI; 2) associations between CI and preoperative pain, disability, and HRQoL; and 3) association between CI and postoperative improvements in HRQoL. Methods: This is a prospective cohort study of 453 consecutive adult spine surgery patients between October 2019 and March 2021. We compared pain (Numeric Rating Scale, NRS), pain-related disability (Oswestry/Neck Disability Index, O/NDI), and HRQoL (PROMIS-29 profile, version 2.0) among participants having severe (PROMIS-29 Cognitive Abilities score ≤30), moderate (31-35), or mild CI (36-40) or who were unimpaired (score >40), using analysis of variance. Likelihood of clinical improvement given the presence of any CI was estimated using logistic regression. All comparisons were adjusted for age, gender, comorbidity, and use of opioid medication during the last 30 days. Alpha=.05. Results: Eighty-five respondents endorsed CI (38 mild; 27 moderate; 20 severe). Preoperatively, those with CI had more severe back pain (p=.005) and neck pain (p=.025) but no differences in leg or arm pain. Those with CI had greater disability on ODI (p<.001) and NDI (p<.001) and worse HRQoL in all domains (all, p<.001). At 6 and 12 months postoperatively, those with CI were less likely to experience clinical improvement in disability and HRQoL (anxiety, pain interference, physical function, and satisfaction with ability to participant in social roles) (all, p<.05). Conclusions: CI was present in nearly 20% of spine patients before surgery and was independently associated with worse preoperative back and neck pain, disability, and HRQoL. Those with CI had approximately one-half the likelihood of achieving meaningful clinical improvement postoperatively. These results indicate a need to evaluate spine patients' cognitive impairment prior to surgery. Level of Evidence: III.

Classification of broadband target spectra in the mesopelagic using physics-informed machine learning.

Broadband echosounders measure the scattering response of an organism over a range of frequencies. When compared with acoustic scattering models, this response can provide insight into the type of organism measured. Here, we train the k-Nearest Neighbors algorithm using scattering models and use it to group target spectra (25-40 kHz) measured in the mesopelagic near the New England continental shelf break. Compared to an unsupervised approach, this creates groupings defined by their scattering physics and does not require significant tuning. The model classifies human-annotated target spectra as gas-bearing organisms (at, below, or above resonance) or fluid-like organisms with a weighted F1-score of 0.90. Class-specific F1-scores varied-the F1-score exceeded 0.89 for all gas-bearing organisms, while fluid-like organisms were classified with an F1-score of 0.73. Analysis of classified target spectra provides insight into the size and distribution of organisms in the mesopelagic and allows for the assessment of assumptions used to calculate organism abundance. Organisms with resonance peaks between 25 and 40 kHz account for 43% of detections, but a disproportionately high fraction of volume backscatter. Results suggest gas bearing organisms account for 98.9% of volume backscattering concurrently measured using a 38 kHz shipboard echosounder between 200 and 800 m depth.

Comparison of mesopelagic organism abundance estimates using in situ target strength measurements and echo-counting techniques.

Recent studies using acoustic techniques suggest that the biomass of mesopelagic fishes may be an order of magnitude higher than previously estimated from trawls. However, there is uncertainty surrounding these estimates, which are derived from shipboard echosounder measurements using necessary, but poorly constrained, assumptions. Here, an echosounder is used to measure individual target strengths at depth. These measurements are used to infer mesopelagic organism density through echo-counting. Measured target strengths are used to estimate organism density by inverting shipboard echosounder measurements. The two sampling methods agree well, but highlight the importance of accurate target strength measurements.

Frequency- and depth-dependent target strength measurements of individual mesopelagic scatterers.

Recent estimates based on shipboard echosounders suggest that 50% or more of global fish biomass may reside in the mesopelagic zone (depths of ∼200-1000 m). Nonetheless, little is known about the acoustic target strengths (TS) of mesopelagic animals because ship-based measurements cannot resolve individual targets. As a result, biomass estimates of mesopelagic organisms are poorly constrained. Using an instrumented tow-body, broadband (18-90 kHz) TS measurements were obtained at depths from 70 to 850 m. A comparison between TS measurements at-depth and values used in a recent global estimate of mesopelagic biomass suggests lower target densities at most depths.

Acoustic characterization of sensors used for marine environmental monitoring.

Active acoustic sensors are widely used in oceanographic and environmental studies. Although many have nominal operating frequencies above the range of marine mammal hearing, they can produce out-of-band sound that may be audible to marine mammals. Acoustic emissions from four active acoustic transducers were characterized and compared to marine mammal hearing thresholds. All four transducers had nominal operating frequencies above the reported upper limit of marine mammal hearing, but produced measurable sound below 160 kHz. A spatial map of the acoustic emissions of each sonar is used to evaluate potential effects on marine mammal hearing when the transducer is continuously operated from a stationary platform. Based on the cumulative sound exposure level metric, the acoustic emissions from the transducers are unlikely to cause temporary threshold shifts in marine mammals, but could affect animal behavior. The extent of audibility is estimated to be, at most, on the order of 100 m.