Search

BackgroundInfection prevention (IP) measures are designed to mitigate the transmission of pathogens in healthcare. Using large-scale viral genomic and social network analyses, we determined if IP measures used during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic were adequate in protecting healthcare workers (HCWs) and patients from acquiring SARS-CoV-2.MethodsWe performed retrospective cross-sectional analyses of viral genomics from all available SARS-CoV-2 viral samples collected at UC San Diego Health and social network analysis using the electronic medical record to derive temporospatial overlap of infections among related viromes and supplemented with contact tracing data. The outcome measure was any instance of healthcare transmission, defined as cases with closely related viral genomes and epidemiological connection within the healthcare setting during the infection window. Between November 2020 through January 2022, 12 933 viral genomes were obtained from 35 666 patients and HCWs.ResultsAmong 5112 SARS-CoV-2 viral samples sequenced from the second and third waves of SARS-CoV-2 (pre-Omicron), 291 pairs were derived from persons with a plausible healthcare overlap. Of these, 34 pairs (12%) were phylogenetically linked: 19 attributable to household and 14 to healthcare transmission. During the Omicron wave, 2106 contact pairs among 7821 sequences resulted in 120 (6%) related pairs among 32 clusters, of which 10 were consistent with healthcare transmission. Transmission was more likely to occur in shared spaces in the older hospital compared with the newer hospital (2.54 vs 0.63 transmission events per 1000 admissions, P < .001).ConclusionsIP strategies were effective at identifying and preventing healthcare SARS-CoV-2 transmission.

Harmful algal blooms (HABs) are increasing globally, causing economic, human health, and ecosystem harm. In spite of the frequent occurrence of HABs, the mechanisms responsible for their exceptionally high biomass remain imperfectly understood. A 50-y-old hypothesis posits that some dense blooms derive from dinoflagellate motility: organisms swim upward during the day to photosynthesize and downward at night to access deep nutrients. This allows dinoflagellates to outgrow their nonmotile competitors. We tested this hypothesis with in situ data from an autonomous, ocean-wave-powered vertical profiling system. We showed that the dinoflagellate Lingulodinium polyedras vertical migration led to depletion of deep nitrate during a 2020 red tide HAB event. Downward migration began at dusk, with the maximum migration depth determined by local nitrate concentrations. Losses of nitrate at depth were balanced by proportional increases in phytoplankton chlorophyll concentrations and suspended particle load, conclusively linking vertical migration to the access and assimilation of deep nitrate in the ocean environment. Vertical migration during the red tide created anomalous biogeochemical conditions compared to 70 y of climatological data, demonstrating the capacity of these events to temporarily reshape the coastal oceans ecosystem and biogeochemistry. Advances in the understanding of the physiological, behavioral, and metabolic dynamics of HAB-forming organisms from cutting-edge observational techniques will improve our ability to forecast HABs and mitigate their consequences in the future.

Unprecedented quantities of heat are entering the Pacific sector of the Arctic Ocean through Bering Strait, particularly during summer months. Though some heat is lost to the atmosphere during autumn cooling, a significant fraction of the incoming warm, salty water subducts (dives beneath) below a cooler fresher layer of near-surface water, subsequently extending hundreds of kilometers into the Beaufort Gyre. Upward turbulent mixing of these sub-surface pockets of heat is likely accelerating sea ice melt in the region. This Pacific-origin water brings both heat and unique biogeochemical properties, contributing to a changing Arctic ecosystem. However, our ability to understand or forecast the role of this incoming water mass has been hampered by lack of understanding of the physical processes controlling subduction and evolution of this this warm water. Crucially, the processes seen here occur at small horizontal scales not resolved by regional forecast models or climate simulations; new parameterizations must be developed that accurately represent the physics. Here we present novel high resolution observations showing the detailed process of subduction and initial evolution of warm Pacific-origin water in the southern Beaufort Gyre.

Cross-shore velocities in the coastal ocean typically vary with depth. The direction and magnitude of transport experienced by meroplanktonic larvae will therefore be influenced by their vertical position. To quantify how swimming behavior and vertical position in internal waves influence larval cross-shore transport in the shallow (~ 20 m), stratified coastal waters off Southern California, we deployed swarms of novel, subsurface larval mimics, the Mini-Autonomous Underwater Explorers (M-AUEs). The M-AUEs were programmed to maintain a specified depth, and were deployed near a mooring. Transport of the M-AUEs was predominantly onshore, with average velocities up to 14 cm s−1. To put the M-AUE deployments into a broader context, we simulated > 500 individual high-frequency internal waves observed at the mooring over a 14-d deployment; in each internal wave, we released both depth-keeping and passive virtual larvae every meter in the vertical. After the waves' passage, depth-keeping virtual larvae were usually found closer to shore than passive larvae released at the same depth. Near the top of the water column (3–5-m depth), ~ 20% of internal waves enhanced onshore transport of depth-keeping virtual larvae by ≥ 50 m, whereas only 1% of waves gave similar enhancements to passive larvae. Our observations and simulations showed that depth-keeping behavior in high-frequency internal waves resulted in enhanced onshore transport at the top of the water column, and reduced offshore dispersal at the bottom, compared to being passive. Thus, even weak depth-keeping may allow larvae to reach nearshore adult habitats more reliably than drifting passively.

Objective: This study aimed to understand the impact of pain management programmes, focusing on the unwanted effects and their influence on patients' long-term use of self-management strategies. Design: Qualitative study. Setting: Specialist musculoskeletal hospital in North London, England. Participants: Patients with chronic musculoskeletal pain that have completed a pain management programme. Intervention: Multidisciplinary pain management programmes. Main measures: Data were collected regarding patients' experiences and unwanted effects from the pain management programme using semi-structured interviews. Data were analysed using thematic analysis. Results: Fourteen participant interviews were included in the analysis (median age 54 years, 12 females). Four themes were generated from the data: Benefits and burdens, Pain management programme and real life, Social support and Healthcare interventions. Unwanted effects included heightened anxiety related to negative interactions with peers, being in a new environment, worries about ability to cope with the programme, social anxiety from being in a group, the strain on families due to participants being away from home and a sense of abandonment at end of the programme. Burdens associated with implementing pain management strategies were identified, including the emotional burden of imposing their self-management on close family and competing demands with time and energy spent on self-management at the expense of work or home commitments. Conclusions: Pain management programmes have an important role in helping patients to learn how to self-manage chronic pain. Their unwanted effects and the treatment burdens associated with long-term self-management may be an important consideration in improving the longevity of their beneficial effects. [ABSTRACT FROM AUTHOR]

The Arabian Sea circulation is forced by strong monsoonal winds and is characterized by vigorous seasonally reversing currents, extreme differences in sea surface salinity, localized substantial upwelling, and widespread submesoscale thermohaline structures. Its complicated sea surface temperature patterns are important for the onset and evolution of the Asian monsoon. This article describes a program that aims to elucidate the role of upper-ocean processes and atmospheric feedbacks in setting the sea surface temperature properties of the region. The wide range of spatial and temporal scales and the difficulty of accessing much of the region with ships due to piracy motivated a novel approach based on state-of-the-art autonomous ocean sensors and platforms. The extensive data set that is being collected, combined with numerical models and remote sensing data, confirms the role of planetary waves in the reversal of the Somali Current system. These data also document the fast response of the upper equatorial ocean to monsoon winds through changes in temperature and salinity and the connectivity of the surface currents across the northern Indian Ocean. New observations of thermohaline interleaving structures and mixing in setting the surface temperature properties of the northern Arabian Sea are also discussed.

The Kuroshio occasionally carries warm and salty North Pacific Water into fresher waters of the South China Sea, forming a front with a complex temperature–salinity (T–S) structure to the west of the Luzon Strait. In this study, we examine the T–S interleavings formed by alternating layers of North Pacific Water with South China Sea Water in a front formed during the winter monsoon season of 2014. Using observations from a glider array following a free-floating wave-powered vertical profiling float to calculate the fine-scale parameters Turner angle, Tu, and Richardson number, Ri, we identified areas favorable to double-diffusion convection and shear instability observed in a T–S interleaving. We evaluated the contribution of double-diffusion convection and shear instabilities to the thermal variance diffusivity, χ, using microstructure data and compared it with previous parameterization schemes based on fine-scale properties. We discover that turbulent mixing is not accurately parameterized when both Tu and Ri are within critical ranges (Tu > 60; Ri < ¼). In particular, χ associated with salt finger processes was an order of magnitude higher (6.7 × 10−7 K2 s−1) than in regions where only velocity shear was likely to drive mixing (8.7 × 10−8 K2 s−1). [ABSTRACT FROM AUTHOR]

This article reports on the recent mining and production status of ruby in Longido, Tanzania. Faceted-grade rubies and their matrix from Longido Area, Tanzania, were investigated by standard gemological testing, including FTIR, UV-VIS, Raman spectra, and LA-ICP-MS. Microscopic observations revealed dense needle-like and triangular inclusions, distinct growth lines, and color banding as typical inclusions. In agreement with the Raman results, the transmission FTIR spectrum confirmed the presence of aluminum hydroxide. The Raman spectra identified associated minerals and inclusions, including zoisite, parasites, feldspar within the matrix, rutile, and diaspore in the ruby host. The chemistry analysis revealed a high amount of Cr and relatively low iron as a good indicator of geographic origin. [ABSTRACT FROM AUTHOR]

Gamma-ray spectroscopy is an effective technique for radioactive material characterization, routine inventory verification, nuclear safeguards, health physics, and source search scenarios. Gamma-ray spectrometers typically cannot be operated in the immediate vicinity of nuclear reactors due to their high flux fields and their resulting inability to resolve individual pulses. Low-power reactor facilities offer the possibility to study reactor gamma-ray fields, a domain of experiments hitherto poorly explored. In this work, we present gamma-ray spectroscopy experiments performed with various detectors in two reactors: The EPFL zero-power research reactor CROCUS, and the neutron beam facility at the Ohio State University Research Reactor (OSURR). We employed inorganic scintillators (CeBr3), organic scintillators (trans-stilbene and organic glass), and high-purity germanium semiconductors (HPGe) to cover a range of typical—and new—instruments used in gamma-ray spectroscopy. The aim of this study is to provide a guideline for reactor users regarding detector performance, observed responses, and therefore available information in the reactor photon fields up to 2 MeV. The results indicate several future prospects, such as the online (at criticality) monitoring of fission products (like Xe, I, and La), dual-particle sensitive experiments, and code validation opportunities. [ABSTRACT FROM AUTHOR]

High resolution shipboard observations reveal the complex processes controlling the evolution and subduction of a cold and salty, dense filament in the Bay of Bengal (BoB). The filament, likely formed through coastal upwelling, was advected offshore by the mesoscale velocity field, and was brought adjacent to a shallow, low salinity mixed layer by mesoscale strain. The front that formed on the Eastern edge of the dense filament was observed to undergo both restratification and steepening, creating barrier layers, in response to evolving mesoscale and submesoscale convergence and divergences. Measurements and analyses indicate that the development of both small‐scale instabilities such as symmetric instability (SI) and slightly larger scale ageostrophic secondary circulation (ASC), acted in concert to subduct and stir surface heat into the interior. These mechanisms also drive the generation of temperature inversions from O (1 km) lateral temperature variability at the surface, demonstrating the need for model parameterizations at such spatial scales. Our results highlight the importance of submesoscale dynamics in creating and warming barrier layers, facilitating vertical heat exchanges, and setting sea surface temperature in the Bay of Bengal, a critical input to coupled atmosphere/ocean models of the southwest monsoon. Such complex dynamics should be considered in regions where salinity governs stratification and compensated waters stir. Plain Language Summary: Improving predictions for the monsoon seasons in the Bay of Bengal depends on the accuracy of the ocean's surface temperatures, which involve both one‐dimensional and three‐dimensional processes that impact the vertical structure of the upper ocean. In this study, we observed a cold and salty water mass that upwelled near the coast of India drift into the center of the Bay where it met ambient low salinity water to create surface lateral density gradients. High‐resolution shipboard observations revealed evidence of small‐scale physical processes as well as features typical of regions where the vertical structure is governed by salinity. The observations document the complexity of upper ocean heat content on scales less than 10 km, with impacts for sea surface temperature and couple ocean ‐atmosphere forecasting of the southwest monsoon. Key Points: The subduction of a dense filament in the Bay of Bengal suggests the role of submesoscale processes in setting upper ocean heat contentBarrier layers form at edges of fronts, sequestering heat from the surface and creating shallow mixed layers with lateral scales O (10 km)Small‐scale lateral temperature variability is exchanged vertically through instabilities, encouraging formation of temperature inversions [ABSTRACT FROM AUTHOR]

Several theories of belief processing assume that processing another's false belief requires overcoming an egocentric bias toward one's current knowledge. The current evidence in support of this claim, however, is limited. In order to investigate the presence of egocentric bias in adult belief processing, computer mouse tracking was used across three experiments to measure attraction toward response options reflecting one's current knowledge while reporting a false belief. Participants viewed scenarios in which an agent either had a true belief or a false belief about the location of a set of keys. Participants used a mouse to answer reality questions "where are the keys currently hidden?" and belief questions "where does she think the keys are?" Mouse-tracking measures indexing attraction toward response options during decision making were measured, along with time taken to make a response and accuracy. Experiment 1 found no evidence, in any measures, that participants showed a bias toward their own knowledge when reporting another's false belief. Experiment 2 investigated whether differences in event timings between true belief and false belief scenarios in Experiment 1 masked an egocentric bias. Experiment 3 investigated whether the lack of egocentric bias could be explained by participants prioritizing encoding the other's beliefs. Neither follow-up experiment found evidence supporting the presence of an egocentric bias. Overall, contrary to many theories of belief processing, our results suggest that adults are readily able to process other people's beliefs without having to overcome a default bias toward their own knowledge. [ABSTRACT FROM AUTHOR]

Evidence gathered three decades ago showed persistently elevated total and new primary production over the continental shelf of the Southern California Bight. This dissertation examines the mechanisms that drive the flux of nitrate necessary to support the phytoplankton productivity over the shelf. Using results gathered from an intensive field experiment, I show that strong, persistent cross-shelf gradients in phytoplankton standing stock, primary productivity and community composition result from nitrate flux due to internal waves of tidal and higher frequency. I report the first estimates of the horizontal flux of nitrate due to the internal tide, and demonstrate that it is quantitatively similar to the nitrate demand of the inner shelf phytoplankton population. The local winds, contrary to expectations based on previous research, support a biologically relevant tilt of the nitracline. Variability in the magnitude of the cross-shore shoaling of the nitracline in turn impacts the magnitude of the internal tide mediated nitrate flux. Remotely-forced large scale variability in the offshore depth of the nitracline controls the continental shelf ‘nitrate climate.’ During episodes of anomalously warm ocean temperatures, a correspondingly deep nitracline can shut off nitrate supply to the continental shelf, resulting in low phytoplankton biomass. During more typical conditions, the phytoplankton community over the inner shelf is dominated by taxa capable of rapid nitrate assimilation, while offshore waters have a proportionally greater amount of oligotrophic species. The results of this dissertation indicate that relatively small changes in the offshore depth of the nitracline could account for the long-term increase primary productivity and phytoplankton biomass noted by recent studies, even in the absence of increased local wind-forced upwelling. Finally, I examine the baroclinic semidiurnal variability in currents and water column structure in the shallow water of the inner shelf. The results of this analysis demonstrate that the behavior of the semidiurnal variability is not consistent with a propagating or standing low mode internal wave. Analyses of linearized momentum balances suggest that the semidiurnal variability may result from the interaction of barotropic tidal flow, friction in the bottom boundary layer, and rotation.

This paper reports on an observation of three-dimensional (3D) arrivals for which the change in the direction of horizontally refracted sound is nearly 180°. The experimental site is Jan Mayen Channel (JMCh), which connects the Greenland and Norwegian Seas. During the experiment, signals from a moored source transmitting a 500–1500 Hz sweep every 4 h were recorded by three surface drifters equipped with hydrophone arrays. Over a 3-day period, the drifters moved north across JMCh toward the moored source. In each recording, an in-plane arrival is identified. In a subset of these recordings, a second arrival is observed, having travel time consistent with propagation from the moored source, turning at the ridge on the south side of the channel, and arriving at the drifters. In a smaller subset of recordings, a third arrival is also observed having travel time consistent with a turning point on the face of the bathymetric rise on the west end of the channel that forms the Jan Mayen volcano. A 3D ray trace is employed to show the change in direction results from repeated reflections from the seafloor such that it is classified as horizontal refraction and not a single-bounce reflection. [ABSTRACT FROM AUTHOR]

This study investigates three-dimensional semidiurnal internal tide (IT) energetics in the vicinity of La Jolla Canyon, a steep shelf submarine canyon off the Southern California coast, with the Stanford Unstructured Nonhydrostatic Terrain-Following Adaptive Navier–Stokes Simulator (SUNTANS) numerical simulator. Numerical simulations show vertical structure and temporal phasing consistent with detailed field observations. ITs induce large (approximately 34 m from peak to peak) isotherm displacements and net onshore IT energy flux up to 200 W m−1. Although the net IT energy flux is onshore, the steep supercritical slope around the canyon results in strong reflection. The model provides the full life span of internal tides around the canyon, including internal tide generation, propagation, and dissipation. ITs propagate into the canyon from the south and are reflected back toward offshore from the canyon's north side. In the inner part of the canyon, elevated mixing occurs in the middle layer due to an interaction between incident mode-1 ITs and reflected higher-mode ITs. The magnitude of IT flux, generation, and dissipation on the south side of the canyon are higher than those on the north side. An interference pattern in horizontal kinetic energy and available potential energy with a scale of approximately 20–50 km arises due to low-mode wave reflections. Our results provide new insight into IT dynamics associated with a small-scale canyon topography. Significance Statement: Internal waves play an important role in ocean circulations and ecosystems. In particular, internal waves with frequencies of tides, known as internal tides, strongly enhance energy, heat, and mass transport in coastal oceans. This study presents internal tide dynamics in La Jolla Canyon, California, using a high-resolution numerical model. Model results show energy convergence in the canyon leading to internal tide energy dissipation and mixing. Some parts of internal tide energy reflect back offshore resulting in standing internal waves off California. This study provides new insights into internal tide dynamics and energy budgets in submarine canyons. [ABSTRACT FROM AUTHOR]