309 research outputs found

    Wood Burning and Creosote Buildup

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    For many years,wood was the prime source of heating the house and continues to be so in some parts of the world. In this country, we are beginning to see many individuals returning to wood burning--using it as an alternate heat source and even occasionally as a primary heat source. Heating with wood, however, is not for everyone. It is not as simple as heating with gas, oil or electricity. It is not as convenient to use because it requires a considerable amount of labor, a large storage area for the wood, more cleaning of the home, many more safety precautions, and acceptance of fluctuating room temperatures. With the development of efficient wood stoves and furnaces, creosote buildup in the chimney became more of a problem because the flue gas temperatures were lower due to more of the heat being put in the room rather than going up the chimney. Creosote clings firmly to the pipe and chimney walls, causing buildup of a very flammable material. When creosote deposits catch fire, the heat is very intense and can result in roof and house fires. Even if the burning creosote does not cause a fire from flying sparks or cracks in the chimney, it tends to weaken the chimney masonry or warp metal chimneys

    Kerosene Heaters

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    Many families are buying supplemental space heating units in an attempt to use heat only where it is needed and thus lower the total heating bill. lf you turn down your central heat thermostat and place such a unit in a room where the family spends most of their waking hours, heating bills may be reduced. Such savings appear to be significant, but each family first needs to carefully consider the safety risks and their energy savings potential as well as the lifestyle changes that might be necessary

    Developing proactive communication strategies for a potential pandemic

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    Communication through the Australian media during a potential avian influenza epidemic could act to inform the public OR misinform, contributing to unnecessary public panic and undesirable responses. This project is part of ongoing research to assess Australians’ knowledge and perceptions of bird flu which will allow the development of public service advertising messages for use by the Australian government in the event of a bird flu outbreak or pandemic. Focus group and CATI survey results on bird flu perceptions were used by an Australian advertising agency to prepare two campaign concepts. The concepts (story boards and print ads) were tested using focus groups by two independent market research companies in July 2006. This paper reports on the results of the ad-testing, and provides recommendations for the development and refinement of a public communication campaign to minimise public panic during a bird flu outbreak or pandemic in Australia

    Chronic Invasive Aspergillosis caused by Aspergillus viridinutans

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    Aspergillus viridinutans, a mold phenotypically resembling A. fumigatus, was identified by gene sequence analyses from 2 patients. Disease was distinct from typical aspergillosis, being chronic and spreading in a contiguous manner across anatomical planes. We emphasize the recognition of fumigati-mimetic molds as agents of chronic or refractory aspergillosis

    Reliability analysis of single crystal NiAl turbine blades

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    As part of a co-operative agreement with General Electric Aircraft Engines (GEAE), NASA LeRC is modifying and validating the Ceramic Analysis and Reliability Evaluation of Structures algorithm for use in design of components made of high strength NiAl based intermetallic materials. NiAl single crystal alloys are being actively investigated by GEAE as a replacement for Ni-based single crystal superalloys for use in high pressure turbine blades and vanes. The driving force for this research lies in the numerous property advantages offered by NiAl alloys over their superalloy counterparts. These include a reduction of density by as much as a third without significantly sacrificing strength, higher melting point, greater thermal conductivity, better oxidation resistance, and a better response to thermal barrier coatings. The current drawback to high strength NiAl single crystals is their limited ductility. Consequently, significant efforts including the work agreement with GEAE are underway to develop testing and design methodologies for these materials. The approach to validation and component analysis involves the following steps: determination of the statistical nature and source of fracture in a high strength, NiAl single crystal turbine blade material; measurement of the failure strength envelope of the material; coding of statistically based reliability models; verification of the code and model; and modeling of turbine blades and vanes for rig testing

    The Discovery of a Second Field Methane Brown Dwarf from Sloan Digital Sky Survey Commissioning Data

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    We report the discovery of a second field methane brown dwarf from the commissioning data of the Sloan Digital Sky Survey (SDSS). The object, SDSS J134646.45-003150.4 (SDSS 1346-00), was selected because of its very red color and stellar appearance. Its spectrum between 0.8-2.5 mic is dominated by strong absorption bands of H_2O and CH_4 and closely mimics those of Gliese 229B and SDSS 162414.37+002915.6 (SDSS 1624+00), two other known methane brown dwarfs. SDSS 1346-00 is approximately 1.5 mag fainter than Gliese 229B, suggesting that it lies about 11 pc from the sun. The ratio of flux at 2.1 mic to that at 1.27 mic is larger for SDSS 1346-00 than for Gliese 229B and SDSS 1624+00, which suggests that SDSS 1346-00 has a slightly higher effective temperature than the others. Based on a search area of 130 sq. deg. and a detection limit of z* = 19.8, we estimate a space density of 0.05 pc^-3 for methane brown dwarfs with T_eff ~ 1000 K in the 40 pc^3 volume of our search. This estimate is based on small-sample statistics and should be treated with appropriate caution.Comment: 9 pages, 3 figures, AASTeX, to appear in ApJ Letters, authors list update

    Arctic system on trajectory to new state

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    The Arctic system is moving toward a new state that falls outside the envelope of glacial-interglacial fluctuations that prevailed during recent Earth history. This future Arctic is likely to have dramatically less permanent ice than exists at present. At the present rate of change, a summer ice-free Arctic Ocean within a century is a real possibility, a state not witnessed for at least a million years. The change appears to be driven largely by feedback-enhanced global climate warming, and there seem to be few, if any processes or feedbacks within the Arctic system that are capable of altering the trajectory toward this “super interglacial” state

    Developmentally Regulated Post-translational Modification of Nucleoplasmin Controls Histone Sequestration and Deposition

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    SummaryNucleoplasmin (Npm) is an abundant histone chaperone in vertebrate oocytes and embryos. During embryogenesis, regulation of Npm histone binding is critical for its function in storing and releasing maternal histones to establish and maintain the zygotic epigenome. Here, we demonstrate that Xenopus laevis Npm post-translational modifications (PTMs) specific to the oocyte and egg promote either histone deposition or sequestration, respectively. Mass spectrometry and Npm phosphomimetic mutations used in chromatin assembly assays identified hyperphosphorylation on the N-terminal tail as a critical regulator for sequestration. C-terminal tail phosphorylation and PRMT5-catalyzed arginine methylation enhance nucleosome assembly by promoting histone interaction with the second acidic tract of Npm. Electron microscopy reconstructions of Npm and TTLL4 activity toward the C-terminal tail demonstrate that oocyte- and egg-specific PTMs cause Npm conformational changes. Our results reveal that PTMs regulate Npm chaperoning activity by modulating Npm conformation and Npm-histone interaction, leading to histone sequestration in the egg

    Developmentally Regulated Post-translational Modification of Nucleoplasmin Controls Histone Sequestration and Deposition

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    SummaryNucleoplasmin (Npm) is an abundant histone chaperone in vertebrate oocytes and embryos. During embryogenesis, regulation of Npm histone binding is critical for its function in storing and releasing maternal histones to establish and maintain the zygotic epigenome. Here, we demonstrate that Xenopus laevis Npm post-translational modifications (PTMs) specific to the oocyte and egg promote either histone deposition or sequestration, respectively. Mass spectrometry and Npm phosphomimetic mutations used in chromatin assembly assays identified hyperphosphorylation on the N-terminal tail as a critical regulator for sequestration. C-terminal tail phosphorylation and PRMT5-catalyzed arginine methylation enhance nucleosome assembly by promoting histone interaction with the second acidic tract of Npm. Electron microscopy reconstructions of Npm and TTLL4 activity toward the C-terminal tail demonstrate that oocyte- and egg-specific PTMs cause Npm conformational changes. Our results reveal that PTMs regulate Npm chaperoning activity by modulating Npm conformation and Npm-histone interaction, leading to histone sequestration in the egg
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