14 research outputs found

    Digitise This! A Quick and Easy Remote Sensing Method to Monitor the Daily Extent of Dredge Plumes

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    Technological advancements in remote sensing and GIS have improved natural resource managers’ abilities to monitor large-scale disturbances. In a time where many processes are heading towards automation, this study has regressed to simple techniques to bridge a gap found in the advancement of technology. The near-daily monitoring of dredge plume extent is common practice using Moderate Resolution Imaging Spectroradiometer (MODIS) imagery and associated algorithms to predict the total suspended solids (TSS) concentration in the surface waters originating from floods and dredge plumes. Unfortunately, these methods cannot determine the difference between dredge plume and benthic features in shallow, clear water. This case study at Barrow Island, Western Australia, uses hand digitising to demonstrate the ability of human interpretation to determine this difference with a level of confidence and compares the method to contemporary TSS methods. Hand digitising was quick, cheap and required very little training of staff to complete. Results of ANOSIM R statistics show remote sensing derived TSS provided similar spatial results if they were thresholded to at least 3 mg L-1. However, remote sensing derived TSS consistently provided false-positive readings of shallow benthic features as Plume with a threshold up to TSS of 6 mg L-1, and began providing false-negatives (excluding actual plume) at a threshold as low as 4 mg L-1. Semi-automated processes that estimate plume concentration and distinguish between plumes and shallow benthic features without the arbitrary nature of human interpretation would be preferred as a plume monitoring method. However, at this stage, the hand digitising method is very useful and is more accurate at determining plume boundaries over shallow benthic features and is accessible to all levels of management with basic training

    Physical mixing effects on iron biogeochemical cycling: FeCycle experiment

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    The effects of physical processes on the distribution, speciation, and sources/sinks for Fe in a high-nutrient low-chlorophyll (HNLC) region were assessed during FeCycle, a mesoscale SF6 tracer release during February 2003 (austral summer) to the SE of New Zealand. Physical mixing processes were prevalent during FeCycle with rapid patch growth (strain rate γ = 0.17–0.20 d−1) from a circular shape (50 km2) into a long filament of ∼400 km2 by day 10. Slippage between layers saw the patch-head overlying noninfused waters while the tail was capped by adjacent surface waters resulting in a SF6 maximum at depth. As the patch developed it entrained adjacent waters containing higher chlorophyll concentrations, but similar dissolved iron (DFe) levels, than the initial infused patch. DFe was low ∼60 pmol L−1 in surface waters during FeCycle and was dominated by organic complexation. Nighttime measurements of Fe(II) ∼20 pmol L−1 suggest the presence of Fe(II) organic complexes in the absence of an identifiable fast Fe(III) reduction process. Combining residence times and phytoplankton uptake fluxes for DFe it is cycled through the biota 140–280 times before leaving the winter mixed layer (WML). This strong Fe demand throughout the euphotic zone coupled with the low Fe:NO3 − (11.9 μmol:mol) below the ferricline suggests that vertical diffusion of Fe is insufficient to relieve chronic iron limitation, indicating the importance of atmospheric inputs of Fe to this region

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    Treatment of subcutaneous phaeohyphomycosis and prospective follow-up of 17 kidney transplant recipients

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    Background: Subcutaneous phaeohyphomycosis in solid organ recipients may have an adverse outcome.Objective. We sought to describe the disease course, treatment, and outcome of allograft function in kidney transplant recipients with phaeohyphomycosis.Methods: Seventeen patients were followed for a mean period of 25.4 months to analyze the clinical response to treatment.Results: There was no treatment failure or relapsing disease among 12 patients who completed treatment. Two patients were still in treatment with disease remission. One patient discontinued the study during treatment with partial remission, one died after finishing treatment with disease remission, and one was dropped from the study because contact was lost. Immunosuppresive regimens were not changed. Two of 17 patients had a significant reduction in allograft function.Limitations: the follow-up time was short and the number of patients was small.Conclusions. the outcome of phaeohyphomycosis in kidney transplant recipients was favorable with minimal impact on renal allograft function. (J Am Acad Dermatol 2009;61:977-85.)Universidade Federal de São Paulo, Dept Dermatol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Med, Div Nephrol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Med, Div Infect Dis, São Paulo, BrazilUniversidade Federal de São Paulo, Div Cellular Biol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Dermatol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Med, Div Nephrol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Med, Div Infect Dis, São Paulo, BrazilUniversidade Federal de São Paulo, Div Cellular Biol, São Paulo, BrazilWeb of Scienc

    Summer and fall habitat of North Atlantic right whales (Eubalaena glacialis) inferred from satellite telemetry

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    Author Posting. © National Research Council Canada, 2005. This article is posted here by permission of National Research Council Canada for personal use, not for redistribution. The definitive version was published in Canadian Journal of Fisheries and Aquatic Sciences 62 (2005): 527-543, doi:10.1139/F04-238.Satellite-monitored radio tags were attached to North Atlantic right whales (Eubalaena glacialis) in Grand Manan Basin of the lower Bay of Fundy during the summer and early fall seasons of 1989–1991 and 2000. Monte Carlo tests were used to examine the distribution of the tagged whales in space and time and with respect to a variety of environmental variables to characterize right whale habitat on their northern feeding grounds. These environmental variables included depth, depth gradient, climatological surface and bottom hydrographic properties, and remotely sensed surface temperature, chlorophyll concentration, and their respective horizontal gradients. Site fidelity in the Bay of Fundy was very low during 1989–1991 and high during 2000. When the tagged animals left the Bay, they did not frequently visit the deep basins of the Gulf of Maine and Scotian Shelf, where abundances of their primary copepod prey, Calanus finmarchicus, are thought to be high. Instead, right whales visited areas characterized by low bottom water temperatures, high surface salinity, and high surface stratification. No evidence was found that the tagged right whales associated with oceanic fronts or regions with high standing stocks of phytoplankton.This study was supported by the Office of Naval Research, National Marine Fisheries Service, Oregon State University Marine Mammal Endowment, and the Space Grant and Earth System Science fellowship programs of the National Aeronautics and Space Administration
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