57 research outputs found

    The AzTEC mm-Wavelength Camera

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    AzTEC is a mm-wavelength bolometric camera utilizing 144 silicon nitride micromesh detectors. Herein we describe the AzTEC instrument architecture and its use as an astronomical instrument. We report on several performance metrics measured during a three month observing campaign at the James Clerk Maxwell Telescope, and conclude with our plans for AzTEC as a facility instrument on the Large Millimeter Telescope.Comment: 13 pages, 15 figures, accepted for publication in Monthly Notice

    Critical Review of Norovirus Surrogates in Food Safety Research: Rationale for Considering Volunteer Studies

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    The inability to propagate human norovirus (NoV) or to clearly differentiate infectious from noninfectious virus particles has led to the use of surrogate viruses, like feline calicivirus (FCV) and murine norovirus-1 (MNV), which are propagatable in cell culture. The use of surrogates is predicated on the assumption that they generally mimic the viruses they represent; however, studies are proving this concept invalid. In direct comparisons between FCV and MNV, their susceptibility to temperatures, environmental and food processing conditions, and disinfectants are dramatically different. Differences have also been noted between the inactivation of NoV and its surrogates, thus questioning the validity of surrogates. Considerable research funding is provided globally each year to conduct surrogate studies on NoVs; however, there is little demonstrated benefit derived from these studies in regard to the development of virus inactivation techniques or food processing strategies. Human challenge studies are needed to determine which processing techniques are effective in reducing NoVs in foods. A major obstacle to clinical trials on NoVs is the perception that such trials are too costly and risky, but in reality, there is far more cost and risk in allowing millions of unsuspecting consumers to contract NoV illness each year, when practical interventions are only a few volunteer studies away. A number of clinical trials have been conducted, providing important insights into NoV inactivation. A shift in research priorities from surrogate research to volunteer studies is essential if we are to identify realistic, practical, and scientifically valid processing approaches to improve food safety

    Alternate unstable states: Convergent paths of succession in hydrocarbon-seep tubeworm-associated communities

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    Previous studies have shown clear, predictable successional trends in habitat characteristics and community structure in tubeworm aggregations at 3 similar hydrocarbon-seep sites on the central upper Louisiana slope of the Gulf of Mexico. In this study, we examine these trends in quantitative community collections from 7 additional hydrocarbon-seep sites widely distributed in the northern Gulf of Mexico. The relative proportions and sizes of Lamellibrachia luymesi and Seepiophila jonesi in tubeworm aggregations were similar at new and central sites, though S. jonesi dominated some collections from new sites, a situation not previously observed at central sites. In general, sulfide declined with increasing aggregation age (average size of tubeworms), but there was more variability in this trend at the new sites. Tubeworm-associated community composition was similar at new and central sites, with only a few rare species collected at the new sites for the first time. The most significant differences in the communities at new sites were the lower relative abundance of various gastropod species, and the absence of gastropods from collections made at the Viosca Knoll site. This community type was largely restricted to young aggregations at new sites that were more isolated from other tubeworm aggregations and consisted of higher proportions of S. jonesi. As succession proceeds from young to old aggregations, many of the previously described processes were apparent at the new sites including a reduction in biomass and a shift in trophic structure from endemic primary consumers to non-endemic higher order predators. Regardless of community composition in young aggregations, succession converges on similar late-stage community types

    Propulsion by impinging laser beams.

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    Bending and flexing of the Apollo 15 mass spectrometer boom.

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    Surface Treatment with 5-Fluorouracil After Flexor Tendon Repair in a Canine in Vivo Model

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    Background: Topical 5-fluorouracil has been reported to reduce adhesions in animal models of tenolysis. The purpose of this study was to investigate the effects of topical 5-fluorouracil on adhesion formation after tendon repairs were subjected to immediate postoperative rehabilitation in a canine model in vivo

    Translating Ruins: An American Parable

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