15,756 research outputs found

    The relationship between andragogical and pedagogical orientation and the implications for adult learning

    Get PDF
    Current literature suggests that the relationship between andragogy and pedagogy is based on a continuum. This study found that the relationship of andragogical and pedagogical orientations, measured by the Students' Orientation Questionnaire, is more correctly represented as being orthogonal or at right angles to each other. Such an orthogonal relationship reflects the complexities involved in adult learning. This paper discusses the implications for both the learning process and for future research

    Charged Condensate and Helium Dwarf Stars

    Full text link
    White dwarf stars composed of carbon, oxygen or heavier elements are expected to crystallize as they cool down below certain temperatures. Yet, simple arguments suggest that the helium white dwarf cores may not solidify, mostly because of zero-point oscillations of the helium ions that would dissolve the crystalline structure. We argue that the interior of the helium dwarfs may instead form a macroscopic quantum state in which the charged helium-4 nuclei are in a Bose-Einstein condensate, while the relativistic electrons form a neutralizing degenerate Fermi liquid. We discuss the electric charge screening, and the spectrum of this substance, showing that the bosonic long-wavelength fluctuations exhibit a mass gap. Hence, there is a suppression at low temperatures of the boson contribution to the specific heat -- the latter being dominated by the specific heat of the electrons near the Fermi surface. This state of matter may have observational signatures.Comment: 10 pages; v2: to appear in JCAP, brief comments and section titles added, typos correcte

    Non equilibrium dynamics below the super-roughening transition

    Full text link
    The non equilibrium relaxational dynamics of the solid on solid model on a disordered substrate and the Sine Gordon model with random phase shifts is studied numerically. Close to the super-roughening temperature TgT_g our results for the autocorrelations, spatial correlations and response function as well as for the fluctuation dissipation ratio (FDR) agree well with the prediction of a recent one loop RG calculation, whereas deep in the glassy low temperature phase substantial deviations occur. The change in the low temperature behavior of these quantities compared with the RG predictions is shown to be contained in a change of the functional temperature dependence of the dynamical exponent z(T)z(T), which relates the age tt of the system with a length scale L(t){\cal L}(t): z(T)z(T) changes from a linear TT-dependence close to TgT_g to a 1/T-behavior far away from TgT_g. By identifying spatial domains as connected patches of the exactly computable ground states of the system we demonstrate that the growing length scale L(t){\cal L}(t) is the characteristic size of thermally fluctuating clusters around ``typical'' long-lived configurations.Comment: RevTex

    Non-contact method for measurement of the microwave conductivity of graphene

    Full text link
    We report a non-contact method for conductivity and sheet resistance measurements of graphene samples using a high Q microwave dielectric resonator perturbation technique, with the aim of fast and accurate measurement of microwave conductivity and sheet resistance of monolayer and few layers graphene samples. The dynamic range of the microwave conductivity measurements makes this technique sensitive to a wide variety of imperfections and impurities and can provide a rapid non-contacting characterisation method. Typically the graphene samples are supported on a low-loss dielectric substrate, such as quartz, sapphire or SiC. This substrate is suspended in the near-field region of a small high Q sapphire puck microwave resonator. The presence of the graphene perturbs both centre frequency and Q value of the microwave resonator. The measured data may be interpreted in terms of the real and imaginary components of the permittivity, and by calculation, the conductivity and sheet resistance of the graphene. The method has great sensitivity and dynamic range. Results are reported for graphene samples grown by three different methods: reduced graphene oxide (GO), chemical vapour deposition (CVD) and graphene grown epitaxially on SiC. The latter method produces much higher conductivity values than the others.Comment: 8 pages, 2 figures and 2 table

    Black Holes Radiate Mainly on the Brane

    Get PDF
    We examine the evaporation of a small black hole on a brane in a world with large extra dimensions. Since the masses of many Kaluza-Klein modes are much smaller than the Hawking temperature of the black hole, it has been claimed that most of the energy is radiated into these modes. We show that this is incorrect. Most of the energy goes into the modes on the brane. This raises the possibility of observing Hawking radiation in future high energy colliders if there are large extra dimensions.Comment: 11 page

    Streptococcus mutans Binding to Collagen, Fibrinogen, Fibronectin, and Laminin

    Get PDF
    poster abstractIntroduction: Streptococcus mutans, nicotine, and certain proteins may be involved in a complicated mechanism that contributes to atherosclerosis. Build up of arterial plaque causes atherosclerosis. Arterial plaque is mainly composed of fat, cholesterol, and calcium. When plaque builds up in the arteries, a clot or blockage can occur and may cause an occlusion. Objective: S. mutans grows in oral biofilm and causes dental caries. These bacteria enter the blood stream from mucosal breaks in the oral cavity. There is evidence that S. mutans binds to endothelial cell surface proteins lining arterial surfaces. An increased incidence of S. mutans in arterial plaque seems to have a direct relationship with atherosclerosis. From preliminary research, there was a strong indication that increased S. mutans biofilm formation is caused by nicotine. The number of binding proteins on nicotine-treated S. mutans cell surface increases as well. In addition, results demonstrated that S. mutans binds to collagen type I, fibrinogen, fibronectin, and laminin, which are proteins found on endothelial cells. Methods: To investigate protein binding, S. mutans UA159 was cultured in 0, 0.25, 0.50, 1.0, 2.0, and 4.0 mg/ml of nicotine and their ability to bind to human collagen type I, fibrinogen, fibronectin and laminin was assessed using an ELISA assay. Results: S. mutans significantly bound to collagen type I and fibrinogen when cultured in 2 and 4 mg/ml nicotine. S. mutans significantly bound to laminin when the bacterium was grown in 1, 2, and 4 mg/ml. The binding of S. mutans to fibronectin varied when cultured in different concentrations of nicotine. Conclusion: From the results, it can be concluded that S. mutans UA159 binds to collagen type I, fibrinogen, fibronectin, and laminin. This indicates that S. mutans and the proteins studied are very likely to be part of the mechanism that leads to atherosclerosis

    Local 4/5-Law and Energy Dissipation Anomaly in Turbulence

    Full text link
    A strong local form of the ``4/3-law'' in turbulent flow has been proved recently by Duchon and Robert for a triple moment of velocity increments averaged over both a bounded spacetime region and separation vector directions, and for energy dissipation averaged over the same spacetime region. Under precisely stated hypotheses, the two are proved to be proportional, by a constant 4/3, and to appear as a nonnegative defect measure in the local energy balance of singular (distributional) solutions of the incompressible Euler equations. Here we prove that the energy defect measure can be represented also by a triple moment of purely longitudinal velocity increments and by a mixed moment with one longitudinal and two tranverse velocity increments. Thus, we prove that the traditional 4/5- and 4/15-laws of Kolmogorov hold in the same local sense as demonstrated for the 4/3-law by Duchon-Robert.Comment: 14 page
    • …
    corecore