161 research outputs found
Opportunistic Sampling at a Deep-water Synthetic Drilling Fluid Discharge Site in the Gulf of Mexico
Two opportunistic benthic surveys were conducted at an offshore semisubmersible oil drilling rig located in 565 m of water on the continental slope of the Gulf of Mexico to determine the extent of synthetic-based drilling fluid (Petrofree LE) concentrations in surrounding sediments and the composition of the associated macrofauna and megafauna communities. Sediment concentrations of Petrofree LE ranged from 89 to 198,320 μg/g in surficial sediments (0-2 cm) and from 4 to 85,821 mg/g in the 2-5 cm stratum. The highest Petrofree LE concentrations were located 50-75 m northeast of the discharge site, a phenomenon that may have been related to surface and midwater currents in the vicinity of the rig. Although no direct quantitative measures of in situ degradation are available, high concentrations of Petrofree LE relative to discharge periodicity suggest lower than anticipated rates at this deep-water site. Between July 1997 and March 1998, the densities of polychaetes and gastropods increased sharply in the study area. In March, polychaete (primarily dorvilleids) density, gastropod density, and Petrofree concentrations were all significantly higher northeast of the drill site compared with southwest. Polychaete and gastropod densities northeast of the drill site were roughly 3,600 and 3,000 times higher than those reported in eastern and western areas of the northern Gulf of Mexico at similar depths, respectively
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Qwu?gwes - A Squaxin Island tribal heritage wet site, Puget Sound, USA
The Qwu?gwes wet site is located at the very head of Puget Sound in Washington State, USA (fig 1). Puget Sound has been referred to as an inland sea, but is better termed as a large glacially cut fjord that is approximately 145km long, running north to south, where the ocean salt water from the Pacific mixes with fresh water draining from the surrounding watersheds. Puget Sound was formed into the north–south fjord it is today by glaciers that advanced from the north at least four times, scouring and carving it for millions of years (Waitt & Thorson 1983). The Vashon Stade was the last major advance, reaching its maximum about 18,000 years ago, covering everything between the Olympic and the Cascade mountains and spreading as far south as our specific region of study. As the Vashon Stade retreated, its melting ice created a massive fresh water lake that released through the Black Lake spillway at the head of Eld Inlet, our site location, and down the Chehalis River drainage to the Pacific Ocean. Once the glaciers melted far enough north, the Straits of Juan de Fuca were open and salt water from the Pacific Ocean entered Puget Sound, making it the salt water ‘inland sea’ it is today (fig 1). Our research area encompasses the southern reaches of the traditional territory of the Lushootseed-speaking Coast Salish People and language family, sometimes referred to as Puget [Sound] Salish (Suttles & Lane 1990, 485–502; Thompson & Kinkade 1990, 38; fig 1). Few systematic archaeological investigations have occurred in this region, especially in the southern section of Lushootseed traditional territory, so this paper should be considered a much needed synthesis of a well-preserved waterlogged site. Qwu?gwes forms the main reference point for our synthesized presentations, and this work is based on the original papers presented by the authors at the 11th International Wetland Archaeology Research Project (WARP) conference in Edinburgh (21–24 September 2005). This joint investigation of the Squaxin Island Tribe and South Puget Sound Community College has been ongoing for several years and provides both a scientific and cultural perspective of the many findings. Earlier publications stress the basis of this joint co-operative effort and the need for co-ordinated scientific and Native cultural understandings and explanations (Foster & Croes 2002, 2004)
Centers for Oceans and Human Health : a unified approach to the challenge of harmful algal blooms
© 2008 Author et al. This is an open access article distributed under the terms of the Creative Commons Attribution License
The definitive version was published in Environmental Health 7 (2008): S2, doi:10.1186/1476-069X-7-S2-S2.Harmful algal blooms (HABs) are one focus of the national research initiatives on Oceans and Human Health (OHH) at NIEHS, NOAA and NSF. All of the OHH Centers, from the east coast to Hawaii, include one or more research projects devoted to studying HAB problems and their relationship to human health. The research shares common goals for understanding, monitoring and predicting HAB events to protect and improve human health: understanding the basic biology of the organisms; identifying how chemistry, hydrography and genetic diversity influence blooms; developing analytical methods and sensors for cells and toxins; understanding health effects of toxin exposure; and developing conceptual, empirical and numerical models of bloom dynamics.
In the past several years, there has been significant progress toward all of the common goals. Several studies have elucidated the effects of environmental conditions and genetic heterogeneity on bloom dynamics. New methods have been developed or implemented for the detection of HAB cells and toxins, including genetic assays for Pseudo-nitzschia and Microcystis, and a biosensor for domoic acid. There have been advances in predictive models of blooms, most notably for the toxic dinoflagellates Alexandrium and Karenia. Other work is focused on the future, studying the ways in which climate change may affect HAB incidence, and assessing the threat from emerging HABs and toxins, such as the cyanobacterial neurotoxin β-N-methylamino-L-alanine.
Along the way, many challenges have been encountered that are common to the OHH Centers and also echo those of the wider HAB community. Long-term field data and basic biological information are needed to develop accurate models. Sensor development is hindered by the lack of simple and rapid assays for algal cells and especially toxins. It is also critical to adequately understand the human health effects of HAB toxins. Currently, we understand best the effects of acute toxicity, but almost nothing is known about the effects of chronic, subacute toxin exposure. The OHH initiatives have brought scientists together to work collectively on HAB issues, within and across regions. The successes that have been achieved highlight the value of collaboration and cooperation across disciplines, if we are to continue to advance our understanding of HABs and their relationship to human health.This work was funded through grants from the NSF/NIEHS Centers for
Oceans and Human Health, NIEHS P50 ES012742 and NSF OCE-043072
(DLE and DMA), NSF OCE04-32479 and NIEHS P50 ES012740 (PB and
RRB), NSF OCE-0432368 and NIEHS P50 ES12736 (LEB), NIEHS P50
ES012762 and NSF OCE-0434087 (RCS, KAL, MSP, MLW, and KAH).
Additional support was provided by the ECOHAB Grant program NSF
Grant OCE-9808173 and NOAA Grant NA96OP0099 (DMA), NOAA
OHHI NA04OAR4600206 (RRB) and Washington State Sea Grant
NA16RG1044 (RCS). KAL and VLT were supported in part by the West
Coast Center for Oceans and Human Health (WCCOHH) as part of the
NOAA Oceans and Human Health Initiative
$1.25 Trillion is Still Real Money: Some Facts About the Effects of the Federal Reserve’s Mortgage Market Investments
The nonmedical use of prescription ADHD medications: results from a national Internet panel
© 2007 Novak et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens
The SPARC Toroidal Field Model Coil Program
The SPARC Toroidal Field Model Coil (TFMC) Program was a three-year effort
between 2018 and 2021 that developed novel Rare Earth Yttrium Barium Copper
Oxide (REBCO) superconductor technologies and then successfully utilized these
technologies to design, build, and test a first-in-class, high-field (~20 T),
representative-scale (~3 m) superconducting toroidal field coil. With the
principal objective of demonstrating mature, large-scale, REBCO magnets, the
project was executed jointly by the MIT Plasma Science and Fusion Center (PSFC)
and Commonwealth Fusion Systems (CFS). The TFMC achieved its programmatic goal
of experimentally demonstrating a large-scale high-field REBCO magnet,
achieving 20.1 T peak field-on-conductor with 40.5 kA of terminal current, 815
kN/m of Lorentz loading on the REBCO stacks, and almost 1 GPa of mechanical
stress accommodated by the structural case. Fifteen internal demountable
pancake-to-pancake joints operated in the 0.5 to 2.0 nOhm range at 20 K and in
magnetic fields up to 12 T. The DC and AC electromagnetic performance of the
magnet, predicted by new advances in high-fidelity computational models, was
confirmed in two test campaigns while the massively parallel, single-pass,
pressure-vessel style coolant scheme capable of large heat removal was
validated. The REBCO current lead and feeder system was experimentally
qualified up to 50 kA, and the crycooler based cryogenic system provided 600 W
of cooling power at 20 K with mass flow rates up to 70 g/s at a maximum design
pressure of 20 bar-a for the test campaigns. Finally, the feasibility of using
passive, self-protection against a quench in a fusion-scale NI TF coil was
experimentally assessed with an intentional open-circuit quench at 31.5 kA
terminal current.Comment: 17 pages 9 figures, overview paper and the first of a six-part series
of papers covering the TFMC Progra
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