106 research outputs found
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Sea breeze forcing of estuary turbulence and air-water CO2 exchange
The sea breeze is often a dominant meteorological feature at the coastline, but little is known about its estuarine impacts. Measurements at an anchored catamaran and meteorological stations along the Hudson River and New York Bay estuarine system are used to illustrate some basic characteristics and impacts of the feature. The sea breeze propagates inland, arriving in phase with peak solar forcing at seaward stations, but several hours later at up-estuary stations. Passage of the sea breeze front raises the water-to-air CO2 flux by 1–2 orders of magnitude, and drives turbulence comparable to spring tide levels in the upper meter of the water column, where most primary productivity occurs in this highly turbid system. Modeling and observational studies often use remotely-measured winds to compute air-water fluxes (e.g., momentum, CO2), and this leads to a factor of two flux error on sea breeze days during the study
Analysis of a Nuclear Accident: Fission and Activation Product Releases from the Fukushima Daiichi Nuclear Facility as Remote Indicators of Source Identification, Extent of Release, and State of Damaged Spent Nuclear Fuel
Evidence of the release Pu from the Fukushima Daiichi nuclear power station to the local environment and surrounding communities and estimates on fraction of total fuel inventory release
Tidal and atmospheric influences on near-surface turbulence in an estuary
Estuarine near-surface turbulence is important for transport, mixing, and air-water exchanges of many important constituents but has rarely been studied in detail. Here, we analyze a unique set of estuarine observations of in situ atmospheric and full water column measurements, estimated air-sea exchanges, and acoustic measurements of several terms in the turbulent kinetic energy (TKE) budget. Observations from a 5.1 m deep site in the Hudson River estuary include dissipation at 50 cm depth (ɛ50), as well as profiles of TKE, shear production of TKE (P), and net turbulent vertical TKE transport (TD). Regressions suggest that the principal controlling factor for ɛ50 was wind (through the surface shear velocity, U*) and that the surface heat flux and tidal currents played a secondary role. For ebb spring tides, the TKE budget at 50 cm depth was closed within noise levels. Ebbs had high ɛ50 due to local shear production, which nearly balanced ɛ50. Floods had TD approaching P in the upper water column but generally weak near-surface shear and turbulence. Examining buoyancy fluxes that impact near-surface stratification and can indirectly control turbulence, solar heat input and tidal straining caused similar buoyancy fluxes on a sunny, calm weather day, promoting ebb tide restratification. Wind-driven mixing was found to dominate during a fall season storm event, and strong overnight heat loss after the storm helped delay restratification afterward. These results demonstrate the utility of combining detailed air-sea interaction and physical oceanographic measurements in future estuary studies
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MULTI-ISOPTOPE PROCESS MONITOR: A COMPARISON OF MODEL AND EXPERIMENTAL VALIDATION
The MIP Monitoring concept was demonstrated through a series of simulations as well as experiments. While qualitatively these studies generated similar results, there were significant differences between the simulated and experimentally determined spectra. This chapter investigates these differences between modeled and experimentally determined CZT gamma spectra and subsequent PCA analysis generated from each
Ampere Hour as a Predictor of Cardiac Resynchronization Defibrillator Pulse Generator Battery Longevity: A Multicenter Study
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/122444/1/pace12831_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/122444/2/pace12831.pd
Relative Sea-Level Trends in New York City During the Past 1500 Years
New York City (NYC) is threatened by 21st-century relative sea-level (RSL) rise because it will experience a trend that exceeds the global mean and has high concentrations of low-lying infrastructure and socioeconomic activity. To provide a long-term context for anticipated trends, we reconstructed RSL change during the past ~1500 years using a core of salt-marsh sediment from Pelham Bay in The Bronx. Foraminifera and bulk-sediment δ13C values were used as sea-level indicators. The history of sediment accumulation was established by radiocarbon dating and recognition of pollution and land-use trends of known age in down-core elemental, isotopic, and pollen profiles. The reconstruction was generated within a Bayesian hierarchical model to accommodate multiple proxies and to provide a unified statistical framework for quantifying uncertainty. We show that RSL in NYC rose by ~1.70 m since ~575 CE (including ~0.38 m since 1850 CE). The rate of RSL rise increased markedly at 1812–1913 CE from ~1.0 to ~2.5 mm/yr, which coincides with other reconstructions along the US Atlantic coast. We investigated the possible influence of tidal-range change in Long Island Sound on our reconstruction using a regional tidal model, and we demonstrate that this effect was likely small. However, future tidal-range change could exacerbate the impacts of RSL rise in communities bordering Long Island Sound. The current rate of RSL rise is the fastest that NYC has experienced for \u3e1500 years, and its ongoing acceleration suggests that projections of 21st-century local RSL rise will be realized
A prospective safety and feasibility study of metered cryospray for patients with chronic bronchitis in COPD
BACKGROUND: No currently approved intervention counteracts airway metaplasia and mucus hypersecretion of Chronic Bronchitis (CB) in COPD. Metered Cryospray (MCS) delivering liquid nitrogen (LN2) to the tracheobronchial airways ablates abnormal epithelium and facilitates healthy mucosal regeneration. The objective of this study was to evaluate the feasibility, efficacy and safety of MCS in CB. METHODS: Patients with a FEV1, 30-80% of expected, taking optimal medication were recruited. Primary outcomes: feasibility - completion of treatments; efficacy - 3-month change in St George's Respiratory Questionnaire (SGRQ); safety - incidence of adverse events (AEs). SECONDARY OUTCOMES: lung function, exercise capacity, additional patient-reported outcomes (PROs). RESULTS: 35 patients, 19 male/16 female, aged 47-76 years, GOLD grade I (3), II (10) and III (22), underwent staggered LN2 treatments to the tracheobronchial tree.34 patients completed three treatments, each lasting 34·3±12·1 min, separated by 4-6 weeks: one withdrew after the first treatment. Approximately 1800 doses of MCS were delivered.Clinically meaningful improvements in PROs were observed at 3-months; ΔSGRQ -6·4 [95% CI -11.4, -1.3; p=0·01], COPD Assessment Test (CAT) -3·8 [95% CI -6.4, -1.3; p<0·01] and Leicester Cough Questionnaire (LCQ) 21·6 [95% CI 7.3, 35.9; p<0·01]. CAT changes were durable to 6-months (-3·4 [95% CI -5.9, -0.9; p=0·01]), SGRQ and LCQ to 9-months (-6·9 [95% CI -13.0, -0.9; p=0·03] and 13·4 [95% 2.1, 24.6; p=0·02], respectively).At 12-months, 14 serious AEs were recorded in 11 (31·4%) subjects, 6 moderate (43%) and 8 severe (57%). 9 were respiratory-related: 6 exacerbations of COPD, 2 pneumonias, and 1, increased coughing, recovered without sequelae. None were serious device or procedure-related AEs. CONCLUSION: MCS is safe, feasible and associated with clinically meaningful improvements in multidimensional PROs
Assessment of microcirculation variables and endothelial glycocalyx using sidestream dark field videomicroscopy in anesthetized dogs undergoing cardiopulmonary bypass
IntroductionTo evaluate microcirculation and endothelial glycocalyx (eGC) variables using sidestream darkfield (SDF) videomicroscopy in canine cardiopulmonary bypass (CPB).MethodsDogs undergoing CPB for surgical correction of naturally-occurring cardiac disease were prospectively included. Variables collected included patient demographics, underlying cardiac disease, red blood cell flow (Flow), 4-25 μm vessel density (Density), absolute capillary blood volume (CBVabs), relative capillary blood volume (CBVrel) and eGC width assessed by perfused boundary region (PBR). Anesthetized healthy dogs were used as control. Microcirculation and eGC variables were compared at baseline under anesthesia (T0), on CPB prior to cross clamping (T1), after cross clamp removal following surgical correction (T2) and at surgical closure (T3).ResultsTwelve dogs were enrolled, including 10 with a complete dataset. Median Flow was 233.9, 79.9, 164.3, and 136.1 μm/s at T0, T1, T2, and T3, respectively, (p = 1.00). Median Density was 173.3, 118.4, 121.0 and 155.4 mm/mm2 at T0, T1, T2, and T3, respectively, (p = 1.00). Median CBVabs decreased over time: 7.4, 6.6, 4.8 and 4.7 103μm3 at T0, T1, T2, and T3, respectively, (p < 0.01). Median CBVrel increased over time: 1.1, 1.5,1.1, and 1.3 103μm3 at T0, T1, T2, and T3, respectively, (p < 0.001). Median PBR increased over time: 1.8, 2.1, 2.4, 2.1 μm at T0, T1, T2, and T3, respectively, (p < 0.001). Compared to control dogs (n = 8), CPB dogs had lower CBVabs at T0.ConclusionAlterations in eGC thickness and microvascular occur in dogs undergoing CPB for naturally-occurring cardiac disease
Comparing aerosol number and mass exhalation rates from children and adults during breathing, speaking and singing
Aerosol particles of respirable size are exhaled when individuals breathe, speak and sing and can transmit respiratory pathogens between infected and susceptible individuals. The COVID-19 pandemic has brought into focus the need to improve the quantification of the particle number and mass exhalation rates as one route to provide estimates of viral shedding and the potential risk of transmission of viruses. Most previous studies have reported the number and mass concentrations of aerosol particles in an exhaled plume. We provide a robust assessment of the absolute particle number and mass exhalation rates from measurements of minute ventilation using a non-invasive Vyntus Hans Rudolf mask kit with straps housing a rotating vane spirometer along with measurements of the exhaled particle number concentrations and size distributions. Specifically, we report comparisons of the number and mass exhalation rates for children (12–14 years old) and adults (19–72 years old) when breathing, speaking and singing, which indicate that child and adult cohorts generate similar amounts of aerosol when performing the same activity. Mass exhalation rates are typically 0.002–0.02 ng s(−1) from breathing, 0.07–0.2 ng s(−1) from speaking (at 70–80 dBA) and 0.1–0.7 ng s(−1) from singing (at 70–80 dBA). The aerosol exhalation rate increases with increasing sound volume for both children and adults when both speaking and singing
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