2,428 research outputs found
Dynamical density functional theory with hydrodynamic interactions and colloids in unstable traps
A density functional theory for colloidal dynamics is presented which
includes hydrodynamic interactions between the colloidal particles. The theory
is applied to the dynamics of colloidal particles in an optical trap which
switches periodically in time from a stable to unstable confining potential. In
the absence of hydrodynamic interactions, the resulting density breathing mode,
exhibits huge oscillations in the trap center which are almost completely
damped by hydrodynamic interactions. The predicted dynamical density fields are
in good agreement with Brownian dynamics computer simulations
Synthesis-Oriented Situational Analysis in User Interface Design
Analytic evaluation is a term describing a class of techniques for examining a representation of a user interface design, discovering design flaws and/or predicting user task performance. In our work with analytic evaluation, we have observed limitations on the effectiveness and efficiency of analytic techniques for formative evaluation supporting the iterative design and re-design cycle. Here we support those observations with arguments based on theoretical limitations of the models underlying these techniques. By way of comparison we discuss desirable characteristics for an alternative approach. In our search for such an alternative, we have developed the Task Mapping Model, a substantively different approach to analysis for supporting the user interface design. We briefly describe the Task Mapping Model and give some examples illustrating its desirable characteristics
Deviation from Snell's Law for Beams Transmitted Near the Critical Angle: Application to Microcavity Lasers
We show that when a narrow beam is incident upon a dielectric interface near
the critical angle for total internal reflection it will be transmitted into
the far-field with an angular deflection from the direction predicted by
Snell's Law, due to a phenomenon we call "Fresnel Filtering". This effect can
be quite large for the parameter range relevant to dielectric microcavity
lasers.Comment: 4 pages, 3 figures (eps), RevTeX 3.1, to be published in Optics
Letter
Fresnel filtering in lasing emission from scarred modes of wave-chaotic optical resonators
We study lasing emission from asymmetric resonant cavity (ARC) GaN
micro-lasers. By comparing far-field intensity patterns with images of the
micro-laser we find that the lasing modes are concentrated on three-bounce
unstable periodic ray orbits, i.e. the modes are scarred. The high-intensity
emission directions of these scarred modes are completely different from those
predicted by applying Snell's law to the ray orbit. This effect is due to the
process of ``Fresnel filtering'' which occurs when a beam of finite angular
spread is incident at the critical angle for total internal reflection.Comment: 4 pages, 3 figures (eps), RevTeX 3.1, submitted to Phys. Rev. Lett;
corrected a minor (transcription) erro
Decorating Metal Oxide Surfaces with Fluorescent Chlorosulfonated Corroles
We have prepared 2,17-bis(chlorosulfonyl)-5,10,15-tris(pentafluorophenyl)corrole (1), 2,17-bis(chlorosulfonyl)-5,10,15-tris(pentafluorophenyl)corrolatoaluminum(III) (1-Al), and 2,17-bis(chlorosulfonyl)-5,10,15-tris(pentafluorophenyl)corrolatogallium(III) (1-Ga). The metal complexes 1-Al and 1-Ga were isolated and characterized by electronic absorption and NMR spectroscopies, as well as by mass spectrometry. Relative emission quantum yields for 1, 1-Al, and 1-Ga, determined in toluene, are 0.094, 0.127, and 0.099, respectively. Reactions between 1, 1-Al, and 1-Ga and TiO2 nanoparticles (NPs) result in corrole–TiO_2 NP conjugates. The functionalized NP surfaces were investigated by solid-state Fourier transform infrared and X-ray photoelectron spectroscopies and by confocal fluorescence imaging. The fluorescence images for 1-Al–TiO_2 and 1-Ga–TiO_2 suggest a promising application of these NP conjugates as contrast agents for noninvasive optical imaging
Preoperative and perioperative use of levosimendan in cardiac surgery: European expert opinion
In cardiac surgery, postoperative low cardiac output has been shown to correlate with increased rates of organ failure and mortality. Catecholamines have been the standard therapy for many years, although they carry substantial risk for adverse cardiac and systemic effects, and have been reported to be associated with increased mortality. On the other hand, the calcium sensitiser and potassium channel opener levosimendan has been shown to improve cardiac function with no imbalance in oxygen consumption, and to have protective effects in other organs. Numerous clinical trials have indicated favourable cardiac and non-cardiac effects of preoperative and perioperative administration of levosimendan. A panel of 27 experts from 18 countries has now reviewed the literature on the use of levosimendan in on-pump and off-pump coronary artery bypass grafting and in heart valve surgery. This panel discussed the published evidence in these various settings, and agreed to vote on a set of questions related to the cardioprotective effects of levosimendan when administered preoperatively, with the purpose of reaching a consensus on which patients could benefit from the preoperative use of levosimendan and in which kind of procedures, and at which doses and timing should levosimendan be administered. Here, we present a systematic review of the literature to report on the completed and ongoing studies on levosimendan, including the newly commenced LEVO-CTS phase III study (NCT02025621), and on the consensus reached on the recommendations proposed for the use of preoperative levosimendan
Global three-parameter model for neutrino oscillations using Lorentz violation
A model of neutrino oscillations is presented that has only three degrees of
freedom and is consistent with existing data. The model is a subset of the
renormalizable sector of the Standard-Model Extension (SME), and it offers an
alternative to the standard three-neutrino massive model. All classes of
neutrino data are described, including solar, reactor, atmospheric, and LSND
oscillations. The disappearance of solar neutrinos is obtained without
matter-enhanced oscillations. Quantitative predictions are offered for the
ongoing MiniBooNE experiment and for the future experiments OscSNS, NOvA, and
T2K.Comment: 12 pages REVTe
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