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Antarctic Circumpolar Deep Water; a Quaternary paleoflow record from the northern Scotia Sea, South Atlantic Ocean

first_imgIn the northern Scotia Sea, the main pathway of Circumpolar Deep Water (CPDW) flows north to pass through a deep gap in the North Scotia Ridge before turning east into the Falkland Trough. A sediment drift has developed on the seabed since the early-middle Miocene, coincident with the opening of Drake Passage and the inception of deep-water flow. Seismic and acoustic surveys show that the drift covers an area of 10,500 km 2 and forms a broadly asymmetrical mound up to 800 m thick. There is a zone of sediment thinning along the northwestern margin, the result of accentuated CPDW flow around rough ocean floor topography. Small debris flows originating around the margins of the drift suggest localized instability and high sediment supply. Four cores 3-9 m long have been recovered from the crest and margins of the drift in water depths of 3900-4300 m. Biostratigraphy and chemostratigraphy reveal that the longest core extends down to oxygen isotope stage 10 (approx. 370 ka). The sediments are predominantly fine-grained contourites and diatom-rich hemipelagites, capped by sandy-silty contourites rich in the planktonic foraminifer Neogloboquadrina pachyderma. Grain-size analysis of the fine fraction, finer than 4 phi (63 mm), combined with radiocarbon (AMS) dating and magnetic susceptibility, provide an indication of relative CPDW strength over the last 18 ka. Shortly after the last glacial maximum (LGM), at approximately 17 ka, silt modes fluctuated from 5.5 phi to up to 6.25 phi; this increased current winnowing is indicative of an unstable CPDW, with stormier glacial benthic conditions producing sporadic, high-energy currents across the drift crest and flanks. At approximately 12,280 ka, an increase in sediment sorting is noted, indicative of a strong flow of CPDW over the drift crest, suggesting an unstable and fluctuating deep-water flow. During deglaciation and into the Holocene, at approximately 10 ka, CPDW flow stabilized, becoming less vigorous across the drift crest and flanks with silt modes from 6 phi to 5.5 phi accompanied by increased sorting of the sediments. The gross average sedimentation rate from the crest of the drift is 11.2 cm/ky compared to 2.3 cm/ky on the southeastern flank. The unsteadiness of CPDW during glacials compared to interglacial periods may be the result of stronger wind forcing and a northward shift in the Polar Front. Older CPDW flow records from the cores suggest variable and cyclic bottom-current flow corresponding to glacial-interglacial episodes. Modern CPDW flow across the crest of the drift averages 11.6 cm s (super -1) but with intermittent benthic storm activity resuspending the fines.last_img read more

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HHS to spend $877 million on new anthrax vaccine

first_img VaxGen Inc., Brisbane, Calif., won the contract to produce and deliver the new vaccine within 3 years, Health and Human Services (HHS) Secretary Tommy Thompson announced in a teleconference this afternoon. Nov 4 HHS news releasehttp://archive.hhs.gov/news/press/2004pres/20041104a.html Russell said development of the vaccine began more than a decade ago at the US Army Medical Research Institute of Infectious Diseases in Maryland. “We have a lot of faith in this vaccine,” he said. “It’s the right way to protect the country from anthrax.” Thompson said the vaccine contract is the first to be issued under the new Project Bioshield, enacted by Congress last July to provide incentives for the production of medical countermeasures against bioterrorism. The law authorizes the government to guarantee it will buy promising vaccines, drugs, and diagnostics for biodefense. The NIAID began funding the development of rPA vaccine in September 2002, the HHS statement said. VaxGen and Avecia, based in Manchester, England, initially won contracts to develop the vaccine. In October 2003 each company won a contract to produce 3 million doses. Referring to the production of the new vaccine, Fauci said, “We’re just getting recombinant DNA technology to spit out a bunch of purified protein that’s identical to the protein the microbe itself would make.” Mar 12, 2004, CIDRAP News story, “HHS to buy up to 75 million doses of new anthrax vaccine” The vaccine consists of a purified form of recombinant protective antigen (rPA), one of three components of the toxin produced by anthrax, HHS said in a news release. The substance triggers antibodies that neutralize anthrax toxin. Lance Gordon, VaxGen president and CEO, said the contract requires the company to deliver the first 25 million doses within 2 years and all 75 million doses within 3 years. The company hopes to begin delivering the first doses early in 2006, according to a news release. The company said vaccine delivered before FDA licensing could be used in an emergency with HHS approval. The contract requires VaxGen to secure an FDA license for use of the vaccine in preexposure and postexposure contexts, HHS reported. Editor’s note: A correction was made in this story Nov 9 to note that the existing licensed anthrax vaccine contains the natural rather than recombinant form of anthrax protective antigen.center_img “Evidence from laboratory and animal research has shown that the rPA vaccine is effective in providing protection against aerosol exposure to deadly anthrax spores,” the HHS statement said. “In addition, clinical testing has shown the rPA vaccine to be safe in humans.” Anthony S. Fauci, MD, director of the National Institute of Allergy and Infectious Diseases (NIAID), said the new vaccine is a more purified product than the existing licensed vaccine, called anthrax vaccine adsorbed (AVA), in that it contains “just the most immunogenic component.” AVA also has anthrax protective antigen, but the vaccine is derived from whole anthrax microbes and therefore contains a mixture of other things as well, he said. The hope is that the vaccine will provide protection with three doses, so that 75 million doses would be enough for 25 million people. The existing vaccine used by the Department of Defense (DoD) requires six doses over 18 months, followed by annual boosters. Last March HHS announced its intention to award a contract for production of 75 million doses and called for submission of proposals by Apr 16. Today’s announcement did not mention Avecia. DoD has been requiring personnel serving in the Middle East to be vaccinated, but the vaccination program was suspended Oct 27 because of a federal court ruling. A judge ruled that the Food and Drug Administration (FDA) did not follow proper procedures in licensing the vaccine for inhalational anthrax. Hundreds of troops have resisted the vaccination because of concerns about possible side effects. In the teleconference, officials declined to say whether DoD will use the new vaccine for its personnel. “As far as I know, the military will make its own decision,” said Phillip Russell, a medical advisor to Thompson. The vaccine will go into the Strategic National Stockpile and be reserved for emergency use, Thompson said. Nov 4, 2004 (CIDRAP News) – Federal health officials today announced the award of an $877 million contract for 75 million doses of a new anthrax vaccine to protect the public and improve on the existing vaccine used by the military. See also:last_img read more

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