4,600 research outputs found

    The molecular structure of isocyanic acid from microwave and infra-red absorption spectra

    Get PDF
    Experimental investigations of the infra-red and microwave spectra of the slightly asymmetric rotor, HNCO, have been made, and the structure of the molecule has been determined

    Analog of Astrophysical Magnetorotational Instability in a Couette-Taylor Flow of Polymer Fluids

    Full text link
    We report experimental observation of an instability in a Couette-Taylor flow of a polymer fluid in a thin gap between two coaxially rotating cylinders in a regime where their angular velocity decreases with the radius while the specific angular momentum increases with the radius. In the considered regime, neither the inertial Rayleigh instability nor the purely elastic instability are possible. We propose that the observed "elasto-rotational" instability is an analog of the magnetorotational instability which plays a fundamental role in astrophysical Keplerian accretion disks.Comment: 4 pages, 1 figur

    Integrating the common variability language with multilanguage annotations for web engineering

    Get PDF
    Web applications development involves managing a high diversity of files and resources like code, pages or style sheets, implemented in different languages. To deal with the automatic generation of custom-made configurations of web applications, industry usually adopts annotation-based approaches even though the majority of studies encourage the use of composition-based approaches to implement Software Product Lines. Recent work tries to combine both approaches to get the complementary benefits. However, technological companies are reticent to adopt new development paradigms such as feature-oriented programming or aspect-oriented programming. Moreover, it is extremely difficult, or even impossible, to apply these programming models to web applications, mainly because of their multilingual nature, since their development involves multiple types of source code (Java, Groovy, JavaScript), templates (HTML, Markdown, XML), style sheet files (CSS and its variants, such as SCSS), and other files (JSON, YML, shell scripts). We propose to use the Common Variability Language as a composition-based approach and integrate annotations to manage fine grained variability of a Software Product Line for web applications. In this paper, we (i) show that existing composition and annotation-based approaches, including some well-known combinations, are not appropriate to model and implement the variability of web applications; and (ii) present a combined approach that effectively integrates annotations into a composition-based approach for web applications. We implement our approach and show its applicability with an industrial real-world system.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Brain amyloid in preclinical Alzheimer\u27s disease is associated with increased driving risk

    Get PDF
    INTRODUCTION: Postmortem studies suggest that fibrillar brain amyloid places people at higher risk for hazardous driving in the preclinical stage of Alzheimer's disease (AD). METHODS: We administered driving questionnaires to 104 older drivers (19 AD, 24 mild cognitive impairment, and 61 cognitive normal) who had a recent (18)F-florbetapir positron emission tomography scan. We examined associations of amyloid standardized uptake value ratios with driving behaviors: traffic violations or accidents in the past 3 years. RESULTS: The frequency of violations or accidents was curvilinear with respect to standardized uptake value ratios, peaking around a value of 1.1 (model r(2) = 0.10, P = .002); moreover, this relationship was evident for the cognitively normal participants. DISCUSSION: We found that driving risk is strongly related to accumulating amyloid on positron emission tomography, and that this trend is evident in the preclinical stage of AD. Brain amyloid burden may in part explain the increased crash risk reported in older adults

    Constants of Geodesic Motion in Higher-Dimensional Black-Hole Spacetimes

    Full text link
    In [arXiv:hep-th/0611083] we announced the complete integrability of geodesic motion in the general higher-dimensional rotating black-hole spacetimes. In the present paper we prove all the necessary steps leading to this conclusion. In particular, we demonstrate the independence of the constants of motion and the fact that they Poisson commute. The relation to a different set of constants of motion constructed in [arXiv:hep-th/0612029] is also briefly discussed.Comment: 8 pages, no figure

    Rotating Black Holes in Higher Dimensions with a Cosmological Constant

    Get PDF
    We present the metric for a rotating black hole with a cosmological constant and with arbitrary angular momenta in all higher dimensions. The metric is given in both Kerr-Schild and Boyer-Lindquist form. In the Euclidean-signature case, we also obtain smooth compact Einstein spaces on associated S^{D-2} bundles over S^2, infinitely many for each odd D\ge 5. Applications to string theory and M-theory are indicated.Comment: 8 pages, Latex. Short version, with more compact notation, of hep-th/0404008. To appear in Phys. Rev. Let

    Dipole Moment and Electric Quadrupole Effects in HNCO and HNCS

    Get PDF
    Interaction of the electric quadrupole moment of the nitrogen nucleus with the molecular electric fields of isocyanic and isothiocyanic acids results in a hyperfine splitting of the rotational trnasitions

    Temperature Dependence of Single-Crystal Spinel (MgAl_2O_4) Elastic Constants from 293 to 423°K Measured by Light-Sound Scattering in the Raman-Nath Region

    Get PDF
    The temperature dependence of single-crystal elastic constants of synthetic stoichiometric MgAl_2O_4 spinel has been measured by the light-sound scattering technique in the Raman-Nath region. The crystal is set into forced vibration by a single crystal LiNbO_3 transducer coupled to one crystal face. A He-Ne Laser beam is diffracted by the stress-induced birefringence inside the crystal. The diffraction angle is determined from the distance between two spots exposed on a photographic plate by the first order diffracted beams as measured by a microdensitometer. The sound wavelength inside the crystal is then inferred from the laser diffraction angle. Combining the sound wavelength with the measured transducer frequency, the velocity inside the crystal is determined typically to a precision of 0·05 per cent. In this method, the measurement of velocity is not dependent on either the determination of sample length or on phase shifts at sample-transducer interface. Velocities of four pure modes, L//[001], T//[001], L//[110], and T//[110](P//[110] are measured in the temperature range between 293 and 423°K. A linear temperature dependence is fit to the data by a least square method
    • …
    corecore