122 research outputs found
Introduction to special section : U.S. GLOBEC : physical processes on Georges Bank (GLOBEC)
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
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 (−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
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
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
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
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
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
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
© 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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