4,253 research outputs found

    MOCVD-Fabricated TiO2 Thin Films: Influence of Growth Conditions on Fibroblast Cells Culture

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    TiO2 thin films with various morphologies were grown on Ti substrates by the LP-MOCVD technique (Low Pressure Chemical Vapour Deposition from Metal-Organic precursor), with titanium tetra-iso-propoxide as a precursor. All the films were prepared in the same conditions except the deposition time. They were characterized by X-ray diffraction, scanning electron microscopy, optical 15 interferometry, water contact angle measurements. MOCVD-fabricated TiO2 thin films are known to be adapted to cell culture for implant requirements. Human gingival fibroblasts were cultured on the various TiO2 deposits. Differences in cell viability (MTT tests) and cell spreading (qualitative assessment) were observed and related to film roughness, wettability and allotropic composition

    Scalar and tensorial topological matter coupled to (2+1)-dimensional gravity:A.Classical theory and global charges

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    We consider the coupling of scalar topological matter to (2+1)-dimensional gravity. The matter fields consist of a 0-form scalar field and a 2-form tensor field. We carry out a canonical analysis of the classical theory, investigating its sectors and solutions. We show that the model admits both BTZ-like black-hole solutions and homogeneous/inhomogeneous FRW cosmological solutions.We also investigate the global charges associated with the model and show that the algebra of charges is the extension of the Kac-Moody algebra for the field-rigid gauge charges, and the Virasoro algebrafor the diffeomorphism charges. Finally, we show that the model can be written as a generalized Chern-Simons theory, opening the perspective for its formulation as a generalized higher gauge theory.Comment: 40 page

    Experiences from online and classroom education in hydroinformatics

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    Universities and other higher education institutions involved in water-related engineering education are facing new challenges in offering lifelong learning services and online educational support. Both the curricula and the form of delivery are changing, as contemporary water problems require interdisciplinary approaches involving diverse and up to date expertise maintained via continuous professional development. Hydroinformatics education faces similar challenges in developing relevant curricula and finding appropriate combinations of course delivery to its target group. This article presents experiences from delivering two hydroinformatics courses in the fields of flood modelling for management (FMM) and decision support systems (DSS) in river basin management that in recent years have been delivered both online and in classroom settings. Comparisons between the two modes of delivery are provided, with the conclusion that online education in this field, although still faced with many challenges, has a promising potential for meeting future educational needs

    Entropy and specific heat for open systems in steady states

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    The fundamental assumption of statistical mechanics is that the system is equally likely in any of the accessible microstates. Based on this assumption, the Boltzmann distribution is derived and the full theory of statistical thermodynamics can be built. In this paper, we show that the Boltzmann distribution in general can not describe the steady state of open system. Based on the effective Hamiltonian approach, we calculate the specific heat, the free energy and the entropy for an open system in steady states. Examples are illustrated and discussed.Comment: 4 pages, 7 figure

    Temporal and Spatial Dependence of Quantum Entanglement from a Field Theory Perspective

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    We consider the entanglement dynamics between two Unruh-DeWitt detectors at rest separated at a distance dd. This simple model when analyzed properly in quantum field theory shows many interesting facets and helps to dispel some misunderstandings of entanglement dynamics. We find that there is spatial dependence of quantum entanglement in the stable regime due to the phase difference of vacuum fluctuations the two detectors experience, together with the interference of the mutual influences from the backreaction of one detector on the other. When two initially entangled detectors are still outside each other's light cone, the entanglement oscillates in time with an amplitude dependent on spatial separation dd. When the two detectors begin to have causal contact, an interference pattern of the relative degree of entanglement (compared to those at spatial infinity) develops a parametric dependence on dd. The detectors separated at those dd with a stronger relative degree of entanglement enjoy longer disentanglement times. In the cases with weak coupling and large separation, the detectors always disentangle at late times. For sufficiently small dd, the two detectors can have residual entanglement even if they initially were in a separable state, while for dd a little larger, there could be transient entanglement created by mutual influences. However, we see no evidence of entanglement creation outside the light cone for initially separable states.Comment: 21 pages, 8 figures. Minor changes. Some plots are re-expressed in logarithmic negativity. No change in the overall result

    Recovery of entanglement lost in entanglement manipulation

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    When an entangled state is transformed into another one with probability one by local operations and classical communication, the quantity of entanglement decreases. This letter shows that entanglement lost in the manipulation can be partially recovered by an auxiliary entangled pair. As an application, a maximally entangled pair can be obtained from two partially entangled pairs with probability one. Finally, this recovery scheme reveals a fundamental property of entanglement relevant to the existence of incomparable states.Comment: 4 pages, 2 figures, REVTeX; minor correction

    Modelling the Pan-Spectral Energy Distributions of Starburst & Active Galaxies

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    We present results of a self-consistent model of the spectral energy distribution (SED) of starburst galaxies. Two parameters control the IR SED, the mean pressure in the ISM and the destruction timescale of molecular clouds. Adding a simplified AGN spectrum provides mixing lines on IRAS color : color diagrams. This reproduces the observed colors of both AGNs and starbursts.Comment: Poster Paper for IAU 222: The Interplay among Black Holes, Stars and ISM in Galactic Nucle
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