7,798 research outputs found

    A wind-tunnel and analytical study of the conversion from wing lift to rotor lift on a composite-lift V/TOL aircraft

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    Wind tunnel and analytical study of conversion from wing lift to rotor lift on composite lift VTOL aircraf

    Collider Inclusive Jet Data and the Gluon Distribution

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    Inclusive jet production data are important for constraining the gluon distribution in the global QCD analysis of parton distribution functions. With the addition of recent CDF and D0 Run II jet data, we study a number of issues that play a role in determining the up-to-date gluon distribution and its uncertainty, and produce a new set of parton distributions that make use of that data. We present in detail the general procedures used to study the compatibility between new data sets and the previous body of data used in a global fit. We introduce a new method in which the Hessian matrix for uncertainties is ``rediagonalized'' to obtain eigenvector sets that conveniently characterize the uncertainty of a particular observable.Comment: Published versio

    Peephole Log Optimization

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    The log files generated while operating a file system in disconnected mode grow to substantial sizes. Eliminating redundant or useless operations in these logs can free up scarce disk space on laptops, reduce replay times, and reduce the frequency of data conflict. Our approach uses a rule-based portable peephole optimizer for compilers. This work suggests a general method of optimization for any system that performs logging at the vnode layer.http://deepblue.lib.umich.edu/bitstream/2027.42/107933/1/citi-tr-95-3.pd

    On Compact Routing for the Internet

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    While there exist compact routing schemes designed for grids, trees, and Internet-like topologies that offer routing tables of sizes that scale logarithmically with the network size, we demonstrate in this paper that in view of recent results in compact routing research, such logarithmic scaling on Internet-like topologies is fundamentally impossible in the presence of topology dynamics or topology-independent (flat) addressing. We use analytic arguments to show that the number of routing control messages per topology change cannot scale better than linearly on Internet-like topologies. We also employ simulations to confirm that logarithmic routing table size scaling gets broken by topology-independent addressing, a cornerstone of popular locator-identifier split proposals aiming at improving routing scaling in the presence of network topology dynamics or host mobility. These pessimistic findings lead us to the conclusion that a fundamental re-examination of assumptions behind routing models and abstractions is needed in order to find a routing architecture that would be able to scale ``indefinitely.''Comment: This is a significantly revised, journal version of cs/050802

    Animal Models of Human Systemic Lupus Erythematosus 1

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    Systemic lupus erythematosus (SLE) is a human autoimmune disease of unknown etiology. Clinical, serologic, immunologic, and pathologic findings are highly variable in different patients and at different times in the same patient. Murine and canine animal models of SLE have been found with clinicopathologic abnormalities resembling those observed in humans. Each animal model has unique characteristics; taken together they reflect the spectrum of disease in human SLE

    Stability of NLO Global Analysis and Implications for Hadron Collider Physics

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    The phenomenology of Standard Model and New Physics at hadron colliders depends critically on results from global QCD analysis for parton distribution functions (PDFs). The accuracy of the standard next-to-leading-order (NLO) global analysis, nominally a few percent, is generally well matched to the expected experimental precision. However, serious questions have been raised recently about the stability of the NLO analysis with respect to certain inputs, including the choice of kinematic cuts on the data sets and the parametrization of the gluon distribution. In this paper, we investigate this stability issue systematically within the CTEQ framework. We find that both the PDFs and their physical predictions are stable, well within the few percent level. Further, we have applied the Lagrange Multiplier method to explore the stability of the predicted cross sections for W production at the Tevatron and the LHC, since W production is often proposed as a standard candle for these colliders. We find the NLO predictions on sigma_W to be stable well within their previously-estimated uncertainty ranges.Comment: 24 pages, 11 figures. Minor changes in response to JHEP referee repor

    Chlamydia trachomatis Genital Tract Infections: When Host Immune Response and the Microbiome Collide

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    © 2016 Genital infections with Chlamydia trachomatis continue to be a major health problem worldwide. While some individuals clear their infection (presumed to be the result of an effective Th1/interferon-γ response), others develop chronic infections and some are prone to repeat infections. In females in particular, chronic asymptomatic infections are common and can lead to pelvic inflammatory disease and infertility. Recent studies suggest that the genital tract microbiota could be a significant factor and explain person-to-person variation in C. trachomatis infections. One hypothesis suggests that C. trachomatis can use its trpBA genes to rescue tryptophan from indole, which is a product of anaerobic members of the genital tract microbiota. Women with particular microbiota types, such as seen in bacterial vaginosis, have increased numbers of anaerobes, and this would enable the chlamydia in these individuals to overcome the host's interferon-γ attempts to eliminate it, resulting in more repeat and/or chronic infections
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