99,364 research outputs found

    Interleukin-12 p40 secretion by cutaneous CD11c(+) and F4/80(+) cells is a major feature of the innate immune response in mice that develop Th1-mediated protective immunity to Schistosoma mansoni

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    Radiation-attenuated (RA) schistosome larvae are potent stimulators of innate immune responses at the skin site of exposure (pinna) that are likely to be important factors in the development of Th1-mediated protective immunity. In addition to causing an influx of neutrophils, macrophages, and dendritic cells (DCs) into the dermis, RA larvae induced a cascade of chemokine and cytokine secretion following in vitro culture of pinna biopsy samples. While macrophage inflammatory protein 1alpha and interleukin-1beta (IL-1beta) were produced transiently within the first few days, the Th1-promoting cytokines IL-12 and IL-18 were secreted at high levels until at least day 14. Assay of C3H/HeJ mice confirmed that IL-12 secretion was not due to lipopolysaccharide contaminants binding Toll-like receptor 4. Significantly, IL-12 p40 secretion was sustained in pinnae from vaccinated mice but not in those from nonprotected infected mice. In contrast, IL-10 was produced from both vaccinated and infected mice. This cytokine regulates IL-12-associated dermal inflammation, since in vaccinated IL-10(-/-) mice, pinna thickness was greatly increased concurrent with elevated levels of IL-12 p40. A significant number of IL-12 p40(+) cells were detected as emigrants from in vitro-cultured pinnae, and most were within a population of rare large granular cells that were Ia(+), consistent with their being antigen-presenting cells. Labeling of IL-12(+) cells for CD11c, CD205, CD8alpha, CD11b, and F4/80 indicated that the majority were myeloid DCs, although a proportion were CD11c(-) F4/80(+), suggesting that macrophages were an additional source of IL-12 in the skin

    Estimating U.S. output growth with vintage data in a state-space framework

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    This study uses a state-space model to estimate the "true" unobserved measure of total output in the U.S. economy. The analysis uses the entire history (i.e., all vintages) of selected real-time data series to compute revisions and corresponding statistics for those series. The revision statistics, along with the most recent data vintage, are used in a state-space model to extract filtered estimates of the "true" series. Under certain assumptions, Monte Carlo simulations suggest this framework can improve published estimates by as much as 30 percent, lasting an average of 11 periods. Real-time experiments using a measure of real gross domestic product show improvement closer to 10 percent, lasting for 1 to 2 quarters.Economic development ; Economic conditions - United States

    Fueling expected inflation

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    Gasoline - Prices ; Inflation (Finance)

    New Symbolic Tools for Differential Geometry, Gravitation, and Field Theory

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    DifferentialGeometry is a Maple software package which symbolically performs fundamental operations of calculus on manifolds, differential geometry, tensor calculus, Lie algebras, Lie groups, transformation groups, jet spaces, and the variational calculus. These capabilities, combined with dramatic recent improvements in symbolic approaches to solving algebraic and differential equations, have allowed for development of powerful new tools for solving research problems in gravitation and field theory. The purpose of this paper is to describe some of these new tools and present some advanced applications involving: Killing vector fields and isometry groups, Killing tensors and other tensorial invariants, algebraic classification of curvature, and symmetry reduction of field equations.Comment: 42 page

    Chameleon effect and the Pioneer anomaly

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    The possibility that the apparent anomalous acceleration of the Pioneer 10 and 11 spacecraft may be due, at least in part, to a chameleon field effect is examined. A small spacecraft, with no thin shell, can have a more pronounced anomalous acceleration than a large compact body, such as a planet, having a thin shell. The chameleon effect seems to present a natural way to explain the differences seen in deviations from pure Newtonian gravity for a spacecraft and for a planet, and appears to be compatible with the basic features of the Pioneer anomaly, including the appearance of a jerk term. However, estimates of the size of the chameleon effect indicate that its contribution to the anomalous acceleration is negligible. We conclude that any inverse-square component in the anomalous acceleration is more likely caused by an unmodelled reaction force from solar-radiation pressure, rather than a chameleon field effect.Comment: 16 pages; to appear in Phys.Rev.

    Cyber-pseudepigraphy: A New Challenge for Higher Education Policy and Management

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    There is no lack of critical literature dealing with cyber-plagiarism and the implications for assessment in higher education. The practice of the selling of academic papers through the Internet is generally included under the category of plagiarism, although it is suggested that this ought to be considered under the separate category of cyber-pseudepigraphy. Pseudepigraphy is defined in this essay as the deliberate ascription of false authorship to a piece of writing, and cyber-pseudepigraphy is defined as using the Internet to have another person write an academic essay or paper, without this authorship being acknowledged. It is suggested that cyber-pseudepigraphy has widespread implications, and five critical issues are discussed. The essay finally raises the prospect of a return to some form of unseen examination as a method of student assessment as a way of dealing with this problem
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