10,384 research outputs found

    Transonic flutter study of a wind-tunnel model of a supercritical wing with/without winglet

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    The model was a 1/6.5-size, semipan version of a wing proposed for an executive-jet-transport airplane. The model was tested with a normal wingtip, a wingtip with winglet, and a normal wingtip ballasted to simulate the winglet mass properties. Flutter and aerodynamic data were acquired at Mach numbers (M) from 0.6 to 0.95. The measured transonic flutter speed boundary for each wingtip configuration had roughly the same shape with a minimum flutter speed near M=0.82. The winglet addition and wingtip mass ballast decreased the wing flutter speed by about 7 and 5 percent, respectively; thus, the winglet effect on flutter was more a mass effect than an aerodynamic effect

    Phase Dynamics of Two Entangled Qubits

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    We make a geometric study of the phases acquired by a general pure bipartite two level system after a cyclic unitary evolution. The geometric representation of the two particle Hilbert space makes use of Hopf fibrations. It allows for a simple description of the dynamics of the entangled state's phase during the whole evolution. The global phase after a cyclic evolution is always an entire multiple of π\pi for all bipartite states, a result that does not depend on the degree of entanglement. There are three different types of phases combining themselves so as to result in the nπn \pi global phase. They can be identified as dynamical, geometrical and topological. Each one of them can be easily identified using the presented geometric description. The interplay between them depends on the initial state and on its trajectory and the results obtained are shown to be in connection to those on mixed states phases.Comment: 9 figures, slightly different version from the accepted on

    Prospective genetic screening decreases the incidence of Abacavir hypersensitivity reactions in the Western Australian HIV cohort study

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    Abacavir therapy is associated with significant drug hypersensitivity in ∼8% of recipients, with retrospective studies indicating a strong genetic association with the HLA-B*5701 allelle. In this prospective study, involving 260 abacavir-naive individuals (7.7% of whom were positive for HLA-B*5701), we confirm the usefulness of genetic risk stratification, with no cases of abacavir hypersensitivity among 148 HLA-B*5701–negative recipients

    Dynamics of the Tippe Top -- properties of numerical solutions versus the dynamical equations

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    We study the relationship between numerical solutions for inverting Tippe Top and the structure of the dynamical equations. The numerical solutions confirm oscillatory behaviour of the inclination angle θ(t)\theta(t) for the symmetry axis of the Tippe Top. They also reveal further fine features of the dynamics of inverting solutions defining the time of inversion. These features are partially understood on the basis of the underlying dynamical equations

    Wachstumsstörungen als Leitsymptom

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    Zusammenfassung: Kleinwuchs als Leitsymptom stellt eine häufige Fragestellung sowohl in der humangenetischen als auch in der pädiatrischen Sprechstunde dar. Definiert ist Kleinwuchs als eine Körperhöhe unter der 3.Perzentile der Norm bzw. unter −2Standardabweichungen. Diese macht sich bemerkbar durch Änderungen der Wachstumsgeschwindigkeit oder des Wachstumsverlaufs, welche grundsätzlich genetisch determiniert, jedoch auch von sekundären Faktoren beeinflussbar sind. Das Spektrum der zugrunde liegenden genetischen Ursachen reicht von Störungen der Wachstumshormonsekretion und -wirkung über Skelettdysplasien bis hin zu komplexen Fehlbildungssyndromen. Die genetische Abklärung stellt somit einen Grundpfeiler zur Beurteilung der Prognose und einer möglichen therapeutischen Intervention dar. Es werden die grundlegenden diagnostischen Überlegungen anhand häufiger Differenzialdiagnosen, deren genetischen Grundlagen und Behandlungsmöglichkeiten aufgeführt: Ullrich-Turner-Syndrom, Léri-Weill-Syndrom, Silver-Russell-Syndrom, Noonan-Syndrom und Achondroplasi

    Temperature and Kinematics of CIV Absorption Systems

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    We use Keck HIRES spectra of three intermediate redshift QSOs to study the physical state and kinematics of the individual components of CIV selected heavy element absorption systems. Fewer than 8 % of all CIV lines with column densities greater than 10^{12.5} cm^{-2} have Doppler parameters b < 6 km/s. A formal decomposition into thermal and non-thermal motion using the simultaneous presence of SiIV gives a mean thermal Doppler parameter b_{therm}(CIV) = 7.2 km/s, corresponding to a temperature of 38,000 K although temperatures possibly in excess of 300,000 K occur occasionally. We also find tentative evidence for a mild increase of temperature with HI column density. Non-thermal motions within components are typically small (< 10 km/s) for most systems, indicative of a quiescent environment. The two-point correlation function (TPCF) of CIV systems on scales up to 500 km/s suggests that there is more than one source of velocity dispersion. The shape of the TPCF can be understood if the CIV systems are caused by ensembles of objects with the kinematics of dwarf galaxies on a small scale, while following the Hubble flow on a larger scale. Individual high redshift CIV components may be the building blocks of future normal galaxies in a hierarchical structure formation scenario.Comment: submitted to the ApJ Letters, March 16, 1996 (in press); (13 Latex pages, 4 Postscript figures, and psfig.sty included

    Precision Measurements of Higgs Couplings: Implications for New Physics Scales

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    The measured properties of the recently discovered Higgs boson are in good agreement with predictions from the Standard Model. However, small deviations in the Higgs couplings may manifest themselves once the currently large uncertainties will be improved as part of the LHC program and at a future Higgs factory. We review typical new physics scenarios that lead to observable modifications of the Higgs interactions. They can be divided into two broad categories: mixing effects as in portal models or extended Higgs sectors, and vertex loop effects from new matter or gauge fields. In each model we relate coupling deviations to their effective new physics scale. It turns out that with percent level precision the Higgs couplings will be sensitive to the multi-TeV regime.Comment: Invited review for Journal of Physics G, 33pp; v2: references added and improved discussion of operator basis in section 2.
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