2,555 research outputs found

    Hardy-Muckenhoupt Bounds for Laplacian Eigenvalues

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    We present two graph quantities Psi(G,S) and Psi_2(G) which give constant factor estimates to the Dirichlet and Neumann eigenvalues, lambda(G,S) and lambda_2(G), respectively. Our techniques make use of a discrete Hardy-type inequality due to Muckenhoupt

    Expression of \u3cem\u3eRhizobium leguminosarum\u3c/em\u3e CFN42 Genes for Lipopolysaccharide in Strains Derived from Different \u3cem\u3eR. leguminosarum\u3c/em\u3e Soil Isolates

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    Two mutant derivatives of Rhizobium leguminosarum ANU843 defective in lipopolysaccharide (LPS) were isolated. The LPS of both mutants lacked O antigen and some sugar residues of the LPS core oligosaccharides. Genetic regions previously cloned from another Rhizobium leguminosarum wild-type isolate, strain CFN42, were used to complement these mutants. One mutant was complemented to give LPS that was apparently identical to the LPS of strain ANU843 in antigenicity, electrophoretic mobility, and sugar composition. The other mutant was complemented by a second CFN42 lps genetic region. In this case the resulting LPS contained O-antigen sugars characteristic of donor strain CFN42 and reacted weakly with antiserum against CFN42 cells, but did not react detectably with antiserum against ANU843 cells. Therefore, one of the CFN42 lps genetic regions specifies a function that is conserved between the two R. leguminosarum wild-type isolates, whereas the other region, at least in part, specifies a strain-specific LPS structure. Transfer of these two genetic regions into wild-type strains derived from R. leguminosarum ANU843 and 128C53 gave results consistent with this conclusion. The mutants derived from strain ANU843 elicited incompletely developed clover nodules that exhibited low bacterial populations and very low nitrogenase activity. Both mutants elicited normally developed, nitrogen-fixing clover nodules when they carried CFN42 lps DNA that permitted synthesis of O-antigen-containing LPS, regardless of whether the O antigen was the one originally made by strain ANU843

    A High Quality Text-To-Speech System Composed of Multiple Neural Networks

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    While neural networks have been employed to handle several different text-to-speech tasks, ours is the first system to use neural networks throughout, for both linguistic and acoustic processing. We divide the text-to-speech task into three subtasks, a linguistic module mapping from text to a linguistic representation, an acoustic module mapping from the linguistic representation to speech, and a video module mapping from the linguistic representation to animated images. The linguistic module employs a letter-to-sound neural network and a postlexical neural network. The acoustic module employs a duration neural network and a phonetic neural network. The visual neural network is employed in parallel to the acoustic module to drive a talking head. The use of neural networks that can be retrained on the characteristics of different voices and languages affords our system a degree of adaptability and naturalness heretofore unavailable.Comment: Source link (9812006.tar.gz) contains: 1 PostScript file (4 pages) and 3 WAV audio files. If your system does not support Windows WAV files, try a tool like "sox" to translate the audio into a format of your choic

    Birds, Bees and Bias: How Absent Sex Ed Standards Fail New York's Students

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    Many public school districts across New York State provide sex-ed instruction that is inaccurate, incomplete and biased, according to Birds, Bees and Bias: How Absent Sex Ed Standards Fail New York's Students. This report examines sex-ed materials used during the 2009-2010 and 2010-11 school years from across New York State

    Leaving the lab behind : Australian students move stamping research to the plant

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    Student Recital

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    Exsolution of Fe-Ni alloy nanoparticles from (La,Sr)(Cr,Fe,Ni)O3 perovskites as potential oxygen transport membrane catalysts for methane reforming

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    Authors acknowledge support from the EPSRC for Platform Grant EP/K015540/1 and EPSRC Capital for Great Technologies Grant EP/L017008/1.(La0.75Sr0.25)(Cr0.5Fe0.5−xNix)O3 perovskites were investigated as potential catalysts for oxygen transport membranes for methane reforming applications. XRD was performed to study the structural changes that took place when Fe was partially substituted by Ni, in both oxidising and reducing environments. TGA measurements demonstrated that the oxygen deficiency of these perovskites under reducing conditions was enhanced by increasing the level of Ni doping, due to the reduction of the Fe3+/Fe4+ and Ni2+ species to lower cation valences. SEM and TEM-EDX analyses showed that upon reduction exsolution of bimetallic Fe–Ni alloy nanoparticles took place on the surface of the perovskite, which was beneficial for the catalyst's activity. The optimum stoichiometry was the (La0.75Sr0.25)(Cr0.5Fe0.35Ni0.15)O3 perovskite, which during catalytic testing, demonstrated 72% CH4 conversion, which was 20 times higher than that of the initial perovskite.PostprintPeer reviewe

    Inventory of Non-Energy Sources of Greenhouse Gas Emissions in Hawaii Phase I

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    International concern for global climate change has stimulated a wide range of data gathering and analysis efforts worldwide. The recognition that certain atmospheric gases, many of which are anthropogenic in origin, have the capacity to absorb infrared radiation-and thus trap heat in the atmosphere--has focused research efforts on these so-called "greenhouse" gases. In order for a country to assess its contribution to such global warming, it must first develop an emissions inventory of greenhouse gas sources and sinks. In the United States, the U.S. Environmental Protection Agency (EPA) has recently published such an inventory (U.S. EPA, 1994) and has been funding the efforts of each state to develop their own inventories of sources of greenhouse gas emissions (U.S. EPA, 1995, hereafter titled the State Phase I Workbook). It is this latter document which serves as the basis for the present report by providing the bulk of its overall methodology.Clean Air Branch, Department of Health, State of Hawai
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