1,860 research outputs found

    Moored observations of synoptic and seasonal variability in the East Greenland Coastal Current

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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): 8838–8857, doi:10.1002/2014JC010134.We present a year-round assessment of the hydrographic variability within the East Greenland Coastal Current on the Greenland shelf from five synoptic crossings and 4 years of moored hydrographic data. From the five synoptic sections the current is observed as a robust, surface intensified flow with a total volume transport of 0.66 ± 0.18 Sv and a freshwater transport of 42 ± 12 mSv. The moorings showed heretofore unobserved variability in the abundance of Polar and Atlantic water masses in the current on synoptic scales. This is exhibited as large vertical displacement of isotherms (often greater than 100 m). Seasonally, the current is hemmed into the coast during the fall by a full depth Atlantic Water layer that has penetrated onto the inner shelf. The Polar Water layer in the current then thickens through the winter and spring seasons increasing the freshwater content in the current; the timing implies that this is probably driven by the seasonally varying export of freshwater from the Arctic and not the local runoff from Greenland. The measured synoptic variability is enhanced during the winter and spring period due to a lower halocline and a concurrent enhancement in the along-coast wind speed. The local winds force much of the high-frequency variability in a manner consistent with downwelling, but variability distinct from downwelling is also visible.This work was funded by the National Science Foundation grant OCE-1130008, NASA grant NNX13AK88G, and the Ocean and Climate Change Institute at the Woods Hole Oceanographic Institution.2015-06-2

    Intrathecal Opioids for Chronic Pain: A Call for Evidence

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/93560/1/j.1526-4637.2012.01456.x.pd

    Intrathecal Opioids for Chronic Pain: A Call for Evidence

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109561/1/pme12576.pd

    The impact of resolution on the representation of Greenland barrier winds and katabatic flows

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    Author Posting. © American Geophysical Union, 2015. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 42 (2015): 3011–3018, doi:10.1002/2015GL063550.Southern Greenland is characterized by a number of low-level high wind speed weather systems that are the result of topographic flow distortion. These systems include barrier winds and katabatic flow that occur along its southeast coast. Global atmospheric reanalyses have proven to be important tools in furthering our understanding of these orographic winds and their role in the climate system. However, there is evidence that the mesoscale characteristics of these systems may be missed in these global products. Here we show that the Arctic System Reanalysis, a higher-resolution regional reanalysis, is able to capture mesoscale features of barrier winds and katabatic flow that are missed or underrepresented in ERA-I, a leading modern global reanalysis. This suggests that our understanding of the impact of these wind systems on the coupled-climate system can be enhanced through the use of higher-resolution regional reanalyses or model data.2015-10-1

    Effect of permafrost thaw on CO2 and CH4 exchange in a western Alaska peatland chronosequence

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    Permafrost soils store over half of global soil carbon (C), and northern frozen peatlands store about 10% of global permafrost C. With thaw, inundation of high latitude lowland peatlands typically increases the surface-atmosphere flux of methane (CH4), a potent greenhouse gas. To examine the effects of lowland permafrost thaw over millennial timescales, we measured carbon dioxide (CO2) and CH4 exchange along sites that constitute a ~1000 yr thaw chronosequence of thermokarst collapse bogs and adjacent fen locations at Innoko Flats Wildlife Refuge in western Alaska. Peak CH4 exchange in July (123 ± 71 mg CH4–C m−2 d−1) was observed in features that have been thawed for 30 to 70 (\u3c100) yr, where soils were warmer than at more recently thawed sites (14 to 21 yr; emitting 1.37 ± 0.67 mg CH4–C m−2 d−1 in July) and had shallower water tables than at older sites (200 to 1400 yr; emitting 6.55 ± 2.23 mg CH4–C m−2 d−1 in July). Carbon lost via CH4 efflux during the growing season at these intermediate age sites was 8% of uptake by net ecosystem exchange. Our results provide evidence that CH4 emissions following lowland permafrost thaw are enhanced over decadal time scales, but limited over millennia. Over larger spatial scales, adjacent fen systems may contribute sustained CH4 emission, CO2 uptake, and DOC export. We argue that over timescales of decades to centuries, thaw features in high-latitude lowland peatlands, particularly those developed on poorly drained mineral substrates, are a key locus of elevated CH4 emission to the atmosphere that must be considered for a complete understanding of high latitude CH4 dynamics

    Self-dual Ginzburg-Landau vortices in a disk

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    We study the properties of the Ginzburg-Laundau model in the self-dual point for a two-dimensional finite system . By a numerical calculation we analyze the solutions of the Euler-Lagrange equations for a cylindrically symmetric ansatz. We also study the self-dual equations for this case. We find that the minimal energy configurations are not given by the Bogomol'nyi equations but by solutions to the Euler Lagrange ones. With a simple approximation scheme we reproduce the result of the numerical calculation.Comment: 8 pages, 4 figures, RevTex macro

    Phenotype-specific association of the TGFBR3 locus with nonsyndromic cryptorchidism

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    PURPOSE: Based on a genome-wide association study of testicular dysgenesis syndrome showing a possible association with TGFBR3, we analyzed data from a larger, phenotypically restricted cryptorchidism population for potential replication of this signal. MATERIALS AND METHODS: We excluded samples based on strict quality control criteria, leaving 844 cases and 2,718 controls of European ancestry that were analyzed in 2 separate groups based on genotyping platform (ie Illumina® HumanHap550, version 1 or 3, or Human610-Quad, version 1 BeadChip in group 1 and Human OmniExpress 12, version 1 BeadChip platform in group 2). Analyses included genotype imputation at the TGFBR3 locus, association analysis of imputed data with correction for population substructure, subsequent meta-analysis of data for groups 1 and 2, and selective genotyping of independent cases (330) and controls (324) for replication. We also measured Tgfbr3 mRNA levels and performed TGFBR3/betaglycan immunostaining in rat fetal gubernaculum. RESULTS: We identified suggestive (p ≤ 1× 10(-4)) association of markers in/near TGFBR3, including rs9661103 (OR 1.40; 95% CI 1.20, 1.64; p = 2.71 × 10(-5)) and rs10782968 (OR 1.58; 95% CI 1.26, 1.98; p = 9.36 × 10(-5)) in groups 1 and 2, respectively. In subgroup analyses we observed strongest association of rs17576372 (OR 1.42; 95% CI 1.24, 1.60; p = 1.67 × 10(-4)) with proximal and rs11165059 (OR 1.32; 95% CI 1.15, 1.38; p = 9.42 × 10(-4)) with distal testis position, signals in strong linkage disequilibrium with rs9661103 and rs10782968, respectively. Association of the prior genome-wide association study signal (rs12082710) was marginal (OR 1.13; 95% CI 0.99, 1.28; p = 0.09 for group 1), and we were unable to replicate signals in our independent cohort. Tgfbr3/betaglycan was differentially expressed in wild-type and cryptorchid rat fetal gubernaculum. CONCLUSIONS: These data suggest complex or phenotype specific association of cryptorchidism with TGFBR3 and the gubernaculum as a potential target of TGFβ signaling
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