Cross-shelf mixing and mid-shelf front dynamics in the Mid-Atlantic Bight evaluated using the radium quartet

Mid-shelf fronts (MSFs) are thought to be ubiquitous in shelf areas. However, their dynamical role in cross-shelf mixing has yet to be fully characterized. In January, February, and April of 2007, radium isotopes (223Ra, t1/2 = 11 d; 224Ra, t1/2 = 3.7 d; 226Ra, t1/2 = 1600 yr; 228Ra, t1/2 = 5.7 yr) were measured along a transect in the Mid-Atlantic Bight to constrain mixing rates at and around a MSF. Cross-shelf eddy diffusivities (Kx) were determined from 223Ra and 224Ra distributions using a variable-depth model. Two key assumptions – minimal advection and negligible benthic radium input – involving the use of 223Ra and 224Ra as tracers of mixing were quantitatively evaluated in order to assess the accuracy of the Kx estimates. Eddy diffusivities over the three-month sampling period range from 0.1 ± 0.05 – 1.6 ± 0.5 × 102 m2 s–1 for 223Ra and from 1.7 ± 0.4 – 2.2 ± 0.6 × 102 m2 s–1 for 224Ra. The temporal variability in Kx is low in comparison to the uncertainty of the derived values, indicating that eddy diffusivity in this area is relatively constant throughout the sampling period. Observations in the Mid-Atlantic Bight differ from theoretical data corresponding to the tidal dispersion frontogenesis model, suggesting that a different mechanism is responsible for MSF formation. Variability in supported 223Ra and 228Ra observed near the front indicates that cross-shelf mixing may be inhibited by MSFs. Conversely, along-shelf transport is enhanced by the front\u27s presence. These results indicate that the equatorward jet associated with the front is capable of effectively transporting dissolved chemicals over hundreds of kilometers

Kinetics of substrate oxidation and hydrogen peroxide production by Mycoplasma mycoides subsp. mycoides Large Colony (LC) type and Mycoplasma mycoides subsp. capri

Mycoplasma mycoides subsp. mycoides Large Colony (LC) type is a pathogen of goats causing contagious agalactia and respiratory disease, found on all continents where small ruminants are kept. It shares close genetic characteristics with M. mycoides subsp. capri. Substrate oxidation by 22 strains of M. mycoides subsp. mycoides LC from nine countries was compared with that of eight strains of M. mycoides subsp. capri from five countries. There was considerable similarity in the substrates used, but substrate saturation coefficients (Ks) varied for different substrates. Substrate utilization patterns and Ks values did not (1) significantly differentiate the LC strains from each other, (2) show any correlation with geographical origin, or (3) distinguish the LC strains from the capri strains. These results support previous studies justifying the reclassification of these subspecies as a single species

Hip Strength Disparities in College Soccer Players: Implications for Injury Risk and Conditioning Practices

The Y-balance Test (YBT) has been used to identify potential risk factors associated with lower extremity injuries (LEI), while mobility and strength assessments are often used to monitor progress following an injury. PURPOSE: This study aimed to explore differences in YBT scores along with lower body mobility and strength in Division I male soccer players who have reported a LEI in the last 12 months (LEI-Y) compared those without reported injuries (LEI-N). METHODS: Twenty-eight male soccer players (age: 20.7 ± 1.8 y; height: 183.8 ± 7.1 cm; mass: 78.5 ± 6.7 kg) completed pre-season evaluations which included YBT, hip strength, hamstring flexibility, and hip and ankle range of motion (ROM). All players were cleared for testing by the head athletic trainer and team physician and had no current LEI precluding them from participating. However, players self-reported if they had experienced a lower extremity injury or surgery in the prior twelve months. Hip adduction and abduction strength was evaluated using a dynamometer and calculated relative to body weight. Hip and ankle ROM were measured using a goniometer, and hamstring flexibility was measured using the sit-and-reach test. The YBT scores and leg length were used to determine a composite score for each leg. Data was presented as means ± standard deviations. RESULTS: For LEI-N, there were no notable imbalances in right to left side comparisons for hip adduction strength (44.8 ± 6.8 vs 43.5 ± 7.5 %) or hip abduction strength (49.2 ± 5.3 vs 49.0 ± 9.1 %). In the LEI-Y group, there was a discernible difference between the right and left side for hip adduction strength (43.7 ± 7.8 vs 41.4 ± 6.1 %) and hip abduction strength (48.4 ± 8.3 vs 45.1 ± 6.3 %). Relative hip strength and ankle ROM scores were also lower overall in the LEI-Y group compared to the LEI-N group, but no such trends were observed for YBT composite scores, hip ROM, or hamstring flexibility. CONCLUSION: The findings of this study indicate that the LEI-Y group had greater bilateral imbalance in lower limb strength, lower hip strength, and lower ankle ROM scores compared with those without injury history. Future research is recommended to evaluate the impact of injury on these markers and examine their associations with future injury risk

Submarine Groundwater Discharge of Rare Earth Elements to a Tidally-Mixed Estuary in Southern Rhode Island

Rare earth element (REE) concentrations were analyzed in surface water and submarine groundwater within the Pettaquamscutt Estuary, located on the western edge of Narragansett Bay in Rhode Island. These water samples were collected along the salinity gradient of the estuary. Rare earth element concentrations in the majority of the groundwater samples are substantially higher than their concentrations in the surface waters. In particular, Nd concentrations in groundwater range from 0.43 nmol kg-1 up to 198 nmol kg-1 (mean ± SD = 42.1 ± 87.2 nmol kg-1), whereas Nd concentrations range between 259 pmol kg-1 and 649 pmol kg-1 (mean ± SD = 421 ± 149 pmol kg-1) in surface waters from the estuary, which is, on average, 100 fold lower than Nd in the groundwaters. Groundwater samples all exhibit broadly similar middle REE (MREE) enriched shale-normalized REE patterns, despite the wide variation in pH of these natural waters (4.87 ≤ pH ≤ 8.13). The similarity of the shale-normalized REE patterns across the observed pH range suggests that weathering of accessory minerals, such as apatite, and/or precipitation of LREE enriched secondary phosphate minerals controls groundwater REE concentrations and fractionation patterns. More specifically, geochemical mixing models suggest that the REE fractionation patterns of the surface waters may be controlled by REE phosphate mineral precipitation during the mixing of groundwater and stream water with incoming water from the Rhode Island Sound. The estimated SGD (Submarine Groundwater Discharge) of Nd to the Pettaquamscutt Estuary is 26 ± 11 mmol Nd day-1, which is in reasonable agreement with the Nd flux of the primary surface water source to the estuary, the Gilbert Stuart Stream (i.e., 36 mmol day-1), and of the same order of magnitude for a site in Florida

Diatom control of the autotrophic community and particle export in the eastern Bering Sea during the recent cold years (2008–2010)

The southeastern Bering Sea has exhibited shifts in climate since the start of the 21st century. The regional climate shifts are manifested in the duration and areal extent of seasonal sea-ice coverage. During a recent cold period (2008–2010) with extensive spring sea-ice cover over the southeastern shelf of the Bering Sea, a total of 77 water column and 24 sediment trap profiles were collected over the shelf and shelf break and analyzed for autotrophic pigment concentrations and elemental (carbon, nitrogen, phosphorus, and silicon) concentrations in suspended and exported particulate material. These results are used to establish the seasonal succession of the autotrophic community and the control that both phytoplankton and zooplankton exert on export production. In spring (April to mid-June), total chlorophyll a (TChl a) concentrations were generally low (i.e., \u3c 1 μg L–1); however, localized phytoplankton blooms near the marginal ice zone (MIZ) lead to elevated spring average TChl a concentrations (i.e., \u3e5 μg L–1). In summer (mid-June to late July), photic zone chlorophyll a concentrations were typically \u3c1 μg L–1 over the shelf and at the shelf break. Diatoms represented the greatest contribution to TChl a (regional averages of 71%–96% in spring and 25%–75% in summer) and autotrophic biomass in spring and summer. This algal class also represented 50%–99% of TChl a associated with particles sinking from the photic zone. The relatively high proportion of phaeophorbide a in sediment trap material indicates that sinking of zooplankton fecal pellets facilitate the export of particles through the water column. Further, zooplankton grazing may be an important process that returns regenerated nutrients to the water column based on the elemental composition of suspended and sinking particles. In colder than average years, the emergence of diatom blooms in the spring MIZ supports the production of abundant large zooplankton, which are a primary food source for juvenile pelagic fishes of economically important species. Therefore, processes in colder than average years may be essential for the transfer of particulate organic carbon from the surface waters and the success of the economically important pelagic fisheries

Randomized trial of complete versus lesion-only revascularization in patients undergoing primary percutaneous coronary intervention for STEMI and Multivessel Disease

BACKGROUND: The optimal management of patients found to have multivessel disease while undergoing primary percutaneous coronary intervention (P-PCI) for ST-segment elevation myocardial infarction is uncertain.   OBJECTIVES: CvLPRIT (Complete versus Lesion-only Primary PCI trial) is a U.K. open-label randomized study comparing complete revascularization at index admission with treatment of the infarct-related artery (IRA) only.   METHODS: After they provided verbal assent and underwent coronary angiography, 296 patients in 7 U.K. centers were randomized through an interactive voice-response program to either in-hospital complete revascularization (n = 150) or IRA-only revascularization (n = 146). Complete revascularization was performed either at the time of P-PCI or before hospital discharge. Randomization was stratified by infarct location (anterior/nonanterior) and symptom onset (≤3 h or >3 h). The primary endpoint was a composite of all-cause death, recurrent myocardial infarction (MI), heart failure, and ischemia-driven revascularization within 12 months.   RESULTS: Patient groups were well matched for baseline clinical characteristics. The primary endpoint occurred in 10.0% of the complete revascularization group versus 21.2% in the IRA-only revascularization group (hazard ratio: 0.45; 95% confidence interval: 0.24 to 0.84; p = 0.009). A trend toward benefit was seen early after complete revascularization (p = 0.055 at 30 days). Although there was no significant reduction in death or MI, a nonsignificant reduction in all primary endpoint components was seen. There was no reduction in ischemic burden on myocardial perfusion scintigraphy or in the safety endpoints of major bleeding, contrast-induced nephropathy, or stroke between the groups.   CONCLUSIONS: In patients presenting for P-PCI with multivessel disease, index admission complete revascularization significantly lowered the rate of the composite primary endpoint at 12 months compared with treating only the IRA. In such patients, inpatient total revascularization may be considered, but larger clinical trials are required to confirm this result and specifically address whether this strategy is associated with improved survival. (Complete Versus Lesion-only Primary PCI Pilot Study [CvLPRIT]; ISRCTN70913605)

How well does wind speed predict air-sea gas transfer in the sea ice zone? A synthesis of radon deficit profiles in the upper water column of the Arctic Ocean

Author Posting. © American Geophysical Union, 2017. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 122 (2017): 3696–3714, doi:10.1002/2016JC012460.We present 34 profiles of radon-deficit from the ice-ocean boundary layer of the Beaufort Sea. Including these 34, there are presently 58 published radon-deficit estimates of air-sea gas transfer velocity (k) in the Arctic Ocean; 52 of these estimates were derived from water covered by 10% sea ice or more. The average value of k collected since 2011 is 4.0 ± 1.2 m d−1. This exceeds the quadratic wind speed prediction of weighted kws = 2.85 m d−1 with mean-weighted wind speed of 6.4 m s−1. We show how ice cover changes the mixed-layer radon budget, and yields an “effective gas transfer velocity.” We use these 58 estimates to statistically evaluate the suitability of a wind speed parameterization for k, when the ocean surface is ice covered. Whereas the six profiles taken from the open ocean indicate a statistically good fit to wind speed parameterizations, the same parameterizations could not reproduce k from the sea ice zone. We conclude that techniques for estimating k in the open ocean cannot be similarly applied to determine k in the presence of sea ice. The magnitude of k through gaps in the ice may reach high values as ice cover increases, possibly as a result of focused turbulence dissipation at openings in the free surface. These 58 profiles are presently the most complete set of estimates of k across seasons and variable ice cover; as dissolved tracer budgets they reflect air-sea gas exchange with no impact from air-ice gas exchange.NSF Arctic Natural Sciences program Grant Number: 12035582017-11-0

Relationship Between the Y-Balance Test and Lower Extremity Strength and Mobility in Collegiate Lacrosse Players

Lacrosse players must make quick directional changes, often on one leg while under force. This demands strength, mobility, and motor control throughout the kinetic chain. The Y-Balance test (YBT) has been used to gauge motor control in athletes. Still, more research on the relationship between the YBT and lower extremity (LE) mobility and strength in lacrosse players is needed. PURPOSE: The purpose of this study was to examine the relationship between YBT scores, hip range of motion (ROM), ankle dorsiflexion, hip abduction (ABD) and adduction (ADD) strength, and passive and active thoracic rotation in male college lacrosse players. METHODS: Fifty Division I male lacrosse players (age: 20 ± 1.6 y; height: 182.0 ± 6.3 cm; weight: 83.2 ± 6.0 kg) performed a YBT including measures of leg length to determine a composite score for the right and left leg (YBT-R and YBT-L, respectively). Thoracic spine active rotation (TS-AR), passive rotation (TS-PR), and range of motion (ROM) at the hip (sum of internal and external rotation) for each limb was measured with a goniometer. Ankle dorsiflexion was assessed using a clinometer instrument. Hip abduction (ABD) and adduction (ADD) strength was measured using a dynamometer and calculated relative to body weight. Hamstring flexibility was measured using the sit-and-reach test. All players were cleared for testing by the team physician and had no current LE injury precluding them from participating. Descriptive statistics were calculated as mean ± standard deviation and Pearson product-moment correlation coefficients were calculated. The level of significance was set at p \u3c 0.05. RESULTS: YBT-R (but not YBT-L) was significantly correlated with TS-AR to the right and left (r = 0.41 and r = 0.31, p \u3c 0.05), and with the sit-and-reach test (r = 0.28, p \u3c 0.05). Both YBT-R and YBT-L were significantly correlated with hip ROM on the right only but with both right and left ankle dorsiflexion (p \u3c 0.05). CONCLUSIONS: YBT scores on the right and left side were related to thoracic spine, hip, and ankle mobility, but not to hip ADD and ABD strength in collegiate male lacrosse players. Hip rotation measures could reflect capabilities for single-leg balance, stability, and proprioception and could improve YBT performance, however further research incorporating alternative LE strength measures is recommended

WHOI Hawaii Ocean Timeseries Station (WHOTS): WHOTS-11 2014 mooring Turnaround Cruise Report

The Woods Hole Oceanographic Institution (WHOI) Hawaii Ocean Timeseries Site (WHOTS), 100 km north of Oahu, Hawaii, is intended to provide long-term, high-quality air-sea fluxes as a part of the NOAA Climate Observation Program. The WHOTS mooring also serves as a coordinated part of the Hawaii Ocean Timeseries (HOT) program, contributing to the goals of observing heat, fresh water and chemical fluxes at a site representative of the oligotrophic North Pacific Ocean. The approach is to maintain a surface mooring outfitted for meteorological and oceanographic measurements at a site near 22.75°N, 158°W by successive mooring turnarounds. These observations will be used to investigate air–sea interaction processes related to climate variability. This report documents recovery of the tenth WHOTS mooring (WHOTS-10) and deployment of the eleventh mooring (WHOTS-11). Both moorings used Surlyn foam buoys as the surface element and were outfitted with two Air–Sea Interaction Meteorology (ASIMET) systems. Each ASIMET system measures, records, and transmits via Argos satellite the surface meteorological variables necessary to compute air–sea fluxes of heat, moisture and momentum. The upper 155 m of the moorings were outfitted with oceanographic sensors for the measurement of temperature, conductivity and velocity in a cooperative effort with R. Lukas of the University of Hawaii. A pCO2 system and ancillary sensors were installed on the buoys in cooperation with Chris Sabine at the Pacific Marine Environmental Laboratory. A set of radiometers were installed in cooperation with Sam Laney at WHOI. The WHOTS mooring turnaround was done on the NOAA ship Hi’ialakai by the Upper Ocean Processes Group of the Woods Hole Oceanographic Institution. The cruise took place between 15 and 23 July 2014. Operations began with deployment of the WHOTS-11 mooring on 16 July. This was followed by meteorological intercomparisons and CTDs. Recovery of the WHOTS-10 mooring took place on 20 July. This report describes these cruise operations, as well as some of the in-port operations and pre-cruise buoy preparations.Funding was provided by the National Oceanic and Atmospheric Administration under Grant No. NA140AR4320158 and the Cooperative Institute for the North Atlantic Region (CINAR