122 research outputs found

    Introduction to special section : U.S. GLOBEC : physical processes on Georges Bank (GLOBEC)

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    Author Posting. © American Geophysical Union, 2003. 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 108, C11 (2003): 8000, doi:10.1029/2003JC002165.Support for the guest editors was provided by NSF grant OCE 02-27679 (RB), the Bedford Institute of Oceanography (PS), and NSF grant OCE 01-07946 (CL)

    Antiparkinson Drug Adherence and Its Association with Health Care Utilization and Economic Outcomes in a Medicare Part D Population

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    AbstractObjectivesWe examine the associations of adherence to antiparkinson drugs (APDs) with health care utilization and economic outcomes among patients with Parkinson’s disease (PD).MethodsBy using 2006–2007 Medicare administrative data, we examined 7583 beneficiaries with PD who filled two or more APD prescriptions during 19 months (June 1, 2006, to December 31, 2007) in the Part D program. Two adherence measures— duration of therapy (DOT) and medication possession ratio (MPR)—were assessed. Negative binomial and gamma generalized linear models were used to estimate the rate ratios (RRs) of all-cause health care utilization and expenditures, respectively, conditional upon adherence, adjusting for survival risk, sample selection, and health-seeking behavior.ResultsApproximately one-fourth of patients with PD had low adherence (MPR < 0.80, 28.7%) or had a short DOT (≤400 days, 23.9%). Increasing adherence to APD therapy was associated with decreased health care utilization and expenditures. For example, compared with patients with low adherence, those with high adherence (MPR = 0.90–1.00) had significantly lower rates of hospitalization (RR = 0.86), emergency room visits (RR = 0.91), skilled nursing facility episodes (RR = 0.67), home health agency episodes (RR = 0.83), physician visits (RR = 0.93), as well as lower total health care expenditures (−2242),measuredover19months.Similarly,lowertotalexpenditure(−2242), measured over 19 months. Similarly, lower total expenditure (−6308) was observed in patients with a long DOT versus those with a short DOT.ConclusionsIn this nationally representative sample, higher adherence to APDs and longer duration of use of APDs were associated with lower all-cause health care utilization and total health care expenditures. Our findings suggest the need for improving medication-taking behaviors among patients with PD to reduce the use of and expenditures for medical resources

    Studies of the Canadian Arctic Archipelago water transport and its relationship to basin-local forcings : results from AO-FVCOM

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    Author Posting. © American Geophysical Union, 2016. 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 121 (2016): 4392–4415, doi:10.1002/2016JC011634.A high-resolution (up to 2 km), unstructured-grid, fully coupled Arctic sea ice-ocean Finite-Volume Community Ocean Model (AO-FVCOM) was employed to simulate the flow and transport through the Canadian Arctic Archipelago (CAA) over the period 1978–2013. The model-simulated CAA outflow flux was in reasonable agreement with the flux estimated based on measurements across Davis Strait, Nares Strait, Lancaster Sound, and Jones Sounds. The model was capable of reproducing the observed interannual variability in Davis Strait and Lancaster Sound. The simulated CAA outflow transport was highly correlated with the along-strait and cross-strait sea surface height (SSH) difference. Compared with the wind forcing, the sea level pressure (SLP) played a dominant role in establishing the SSH difference and the correlation of the CAA outflow with the cross-strait SSH difference can be explained by a simple geostrophic balance. The change in the simulated CAA outflow transport through Davis Strait showed a negative correlation with the net flux through Fram Strait. This correlation was related to the variation of the spatial distribution and intensity of the slope current over the Beaufort Sea and Greenland shelves. The different basin-scale surface forcings can increase the model uncertainty in the CAA outflow flux up to 15%. The daily adjustment of the model elevation to the satellite-derived SSH in the North Atlantic region outside Fram Strait could produce a larger North Atlantic inflow through west Svalbard and weaken the outflow from the Arctic Ocean through east Greenland.NSF Grant Numbers: OCE-1203393, PLR-1203643; National Natural Science Foundation of China Grant Number: 41276197; Shanghai Pujiang Program Grant Number: 12PJ1404100; Shanghai Shuguang Program2016-12-2

    Ocean variability contributing to basal melt rate near the ice front of Ross Ice Shelf, Antarctica

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    Author Posting. © American Geophysical Union, 2014. 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 119 (2014): 4214–4233, doi:10.1002/2014JC009792.Basal melting of ice shelves is an important, but poorly understood, cause of Antarctic ice sheet mass loss and freshwater production. We use data from two moorings deployed through Ross Ice Shelf, ∼6 and ∼16 km south of the ice front east of Ross Island, and numerical models to show how the basal melting rate near the ice front depends on sub-ice-shelf ocean variability. The moorings measured water velocity, conductivity, and temperature for ∼2 months starting in late November 2010. About half of the current velocity variance was due to tides, predominantly diurnal components, with the remainder due to subtidal oscillations with periods of a few days. Subtidal variability was dominated by barotropic currents that were large until mid-December and significantly reduced afterward. Subtidal currents were correlated between moorings but uncorrelated with local winds, suggesting the presence of waves or eddies that may be associated with the abrupt change in water column thickness and strong hydrographic gradients at the ice front. Estimated melt rate was ∼1.2 ± 0.5 m a−1 at each site during the deployment period, consistent with measured trends in ice surface elevation from GPS time series. The models predicted similar annual-averaged melt rates with a strong annual cycle related to seasonal provision of warm water to the ice base. These results show that accurately modeling the high spatial and temporal ocean variability close to the ice-shelf front is critical to predicting time-dependent and mean values of meltwater production and ice-shelf thinning.The Woods Hole Oceanographic Institution (WHOI) participation in the ANDRILL Coulman High Program was supported by the National Science Foundation Office of Polar Programs (NSF ANT-0839108) through a subcontract from the University of Nebraska, Lincoln (UNL 25-0550-0004-004). I. Arzeno was supported as a 2011 WHOI Summer Student Fellow through the NSF Research Experiences for Undergraduates program (OCE- 0649139). L. Padman and S. Springer were supported by NASA grant NNX10AG19G to Earth & Space Research (ESR). M. Williams and C. Stewart were supported by the New Zealand National Institute of Water and Atmosphere (NIWA) core funding under the National Climate Centre, and the Ministry of Business, Innovation, and Employment (Contract CO5X1001).2015-01-0

    CODE-1 : moored array and large-scale data report

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    The Coastal Ocean Dynamics Experiment (CODE) was undertaken to identify and study the important dynamical processes which govern the wind-driven motion of coastal water over the continental shelf. The initial effort in this multi-year, multi-institutional research program was to obtain high-quality data sets of all the relevant physical variables needed to construct accurate kinematic and dynamic descriptions of the response of shelf water to strong wind forcing in the 2 to 10 day band. A series of two small-scale, densely-instrumented field experiments of approximately four months duration (called CODE-1 and CODE-2) were designed to explore and to determine the kinematics and momentum and heat balances of the local wind-driven flow over a region of the northern California shelf which is characterized by both relatively simple bottom topography and large wind stress events in both winter and summer. A more lightly instrumented, long-term, large-scale component was designed to help separate the local wind-driven response in the region of the small-scale experiments from motions generated either offshore by the California Current system or in some distant region along the coast, and also to help determine the seasonal cycles of the atmospheric forcing, water structure, and coastal currents over the northern California shelf. The first small-scale experiment (CODE-1) was conducted between April and August, 1981 as a pilot study in which primary emphasis was placed on characterizing the wind-driven "signal" and the "noise" from which this signal must be extracted. In particular, CODE-1 was designed to identify the key features of the circulation and its variability over the northern California shelf and to determine the important time and length scales of the wind-driven response. This report presents a basic description of the moored array data and some other Eulerian data collected during CODE-1. A brief description of the CODE-1 field program is presented first, followed by a description of the common data analysis procedures used to produce the various data sets presented here. Then basic descriptions of the following data sets are presented: (a) the coastal and moored meteorological measurements, (b) the moored current measurements, (c) the moored temperature and conductivity observations, (d) the bottom pressure measurements, and (e) the wind and adjusted coastal sea level observations obtained as part of the CODE-1 large-scale component.Prepared for the National Science Foundation under Grant OCE 80-14941

    Numerical study of circulation on the inner Amazon Shelf

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    Author Posting. © Springer, 2008. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Ocean Dynamics 58 (2008): 187-198, doi:10.1007/s10236-008-0139-4.We studied the circulation on the coastal domain of the Amazon Shelf by applying the hydrodynamic module of the Estuarine and Coastal Ocean Model and Sediment Transport - ECOMSED. The first barotropic experiment aimed to explain the major bathymetric effects on tides and those generated by anisotropy in sediment distribution. We analyzed the continental shelf response of barotropic tides under realistic bottom stress parametrization (Cd), considering sediment granulometry obtained from a faciologic map, where river mud deposits and reworked sediments areas are well distinguished, among others classes of sediments. Very low Cd values were set in the fluid mud regions off the Amapa coast (1.0 10-4 ), in contrast to values around 3:5 10-3 for coarser sediment regions off the Para coast. Three-dimensional experiments represented the Amazon River discharge and trade winds, combined to barotropic tide influences and induced vertical mixing. The quasi-resonant response of the Amazon Shelf to the M2 tide act on the local hydrodynamics by increasing tidal admittance, along with tidal forcing at the shelf break and extensive fluid mud regions. Harmonic analysis of modeled currents agreed well with analysis of the AMASSEDS observational data set. Tidal-induced vertical shear provided strong homogenization of threshold waters, which are subject to a kind of hydraulic control due to the topographic steepness. Ahead of the hydraulic jump, the low-salinity plume is disconnected from the bottom and acquires negative vorticity, turning southeastward. Tides act as a generator mechanism and topography, via hydraulic control, as a maintainer mechanism for the low-salinity frontal zone positioning. Tidally induced southeastward plume fate is overwhelmed by northwestward trade winds so that, along with background circulation, probably play the most important role on the plume fate and variability over the Amazon Shelf

    Neurochemical Metabolomics Reveals Disruption to Sphingolipid Metabolism Following Chronic Haloperidol Administration

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    Haloperidol is an effective antipsychotic drug for treatment of schizophrenia, but prolonged use can lead to debilitating side effects. To better understand the effects of long-term administration, we measured global metabolic changes in mouse brain following 3 mg/kg/day haloperidol for 28 days. These conditions lead to movement-related side effects in mice akin to those observed in patients after prolonged use. Brain tissue was collected following microwave tissue fixation to arrest metabolism and extracted metabolites were assessed using both liquid and gas chromatography mass spectrometry (MS). Over 300 unique compounds were identified across MS platforms. Haloperidol was found to be present in all test samples and not in controls, indicating experimental validity. Twenty-one compounds differed significantly between test and control groups at the p < 0.05 level. Top compounds were robust to analytical method, also being identified via partial least squares discriminant analysis. Four compounds (sphinganine, N-acetylornithine, leucine and adenosine diphosphate) survived correction for multiple testing in a non-parametric analysis using false discovery rate threshold < 0.1. Pathway analysis of nominally significant compounds (p < 0.05) revealed significant findings for sphingolipid metabolism (p = 0.02) and protein biosynthesis (p = 0.03). Altered sphingolipid metabolism is suggestive of disruptions to myelin. This interpretation is supported by our observation of elevated N-acetylaspartylglutamate in the haloperidol-treated mice (p = 0.004), a marker previously associated with demyelination. This study further demonstrates the utility of murine neurochemical metabolomics as a method to advance understanding of CNS drug effects

    Seasonal variation of upwelling in the Alaskan Beaufort Sea : impact of sea ice cover

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    Author Posting. © American Geophysical Union, 2012. 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 117 (2012): C06022, doi:10.1029/2012JC007985.Data from a mooring array deployed from August 2002 to September 2004 are used to characterize differences in upwelling near the shelf break in the Alaskan Beaufort Sea due to varying sea ice conditions. The record is divided into three ice seasons: open water, partial ice, and full ice. The basic response is the same in each of the seasons. Roughly 8 h after the onset of easterly winds the shelf break jet reverses, followed approximately 10 h later by upwelling of saltier water which is cold near the shelf break (Pacific Winter Water) and warm at depth (Atlantic Water). The secondary circulation at the outer shelf is, to first order, consistent with a two-dimensional Ekman balance of offshore flow in the upper layer and onshore flow at depth. There are, however, important seasonal differences in the upwelling. Overall the response is strongest in the partial ice season and weakest in the full ice season. It is believed that these differences are dictated by the degree to which wind stress is transmitted through the pack-ice, as the strength of the wind-forcing was comparable over the three seasons. An EOF-based upwelling index is constructed using information about the primary flow, secondary flow, and hydrography. The ability to predict upwelling using the wind record alone is explored, which demonstrates that 90% of easterly wind events exceeding 9.5 m s−1 drive significant upwelling. During certain periods the ice cover on the shelf became landfast, which altered the upwelling and circulation patterns near the shelf break.The following grants provided support for this study: National Ocean Partnership Program project N00014-07-1-1040 and National Science Foundation projects OPP-0731928 and OPP-0713250.2012-12-2

    Estimating stable isotope turnover rates of epidermal mucus and dorsal muscle for an omnivorous fish using a diet-switch experiment

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    © 2018, The Author(s). Stable isotope (SI) analysis studies rely on knowledge of isotopic turnover rates and trophic-step discrimination factors. Epidermal mucus (‘mucus’) potentially provides an alternative SI ‘tissue’ to dorsal muscle that can be collected non-invasively and non-destructively. Here, a diet-switch experiment using the omnivorous fish Cyprinus carpio and plant- and fish-based formulated feeds compared SI data between mucus and muscle, including their isotopic discrimination factors and turnover rates (as functions of time T and mass G, at isotopic half-life (50) and equilibrium (95)). Mucus isotope data differed significantly and predictively from muscle data. The fastest δ13C turnover rate was for mucus in fish on the plant-based diet (T50: 17 days, T95: 74 days; G50: 1.08(BM), G95: 1.40(BM)). Muscle turnover rates were longer for the same fish (T50: 44 days, T95: 190 days; G50: 1.13(BM), G95: 1.68(BM)). Longer half-lives resulted in both tissues from the fish-based diet. δ13C discrimination factors varied by diet and tissue (plant-based: 3.11–3.28‰; fishmeal: 1.28–2.13‰). Mucus SI data did not differ between live and frozen fish. These results suggest that mucus SI half-lives provide comparable data to muscle, and can be used as a non-destructive alternative tissue in fish-based SI studies
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