2,791 research outputs found

    The Issues and Challenges of Assessing Media Literacy Education

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    In the media literacy literature, the challenges associated with assessment have, to a great extent, been ignored. The purpose of this mixed methods study was therefore to explore the views of media literacy scholars and professionals on assessment challenges through qualitative interviews (n = 10) with the intent of using this information to develop a quantitative survey to validate and extend the qualitative findings with a larger sample of media literacy professionals and scholars from around the world (n = 133). The findings offer an overview of the assessment challenges encountered by these participants

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    The Central Retail Food Market of Cleveland, Ohio

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    A study of the Central Retail Food Market in Cleveland, Ohio was made in 1947 at the request of Mayor Thomas A. Burke (Marketing and Facilities Research Branch 3 of the Production and Marketing Administration, U.S. Department of Agriculture) to determine the public need for a new market. In the previous year the city had voted favorably on a bond issue of $1,000,000 for the relocation and rebuilding of the market, provided it could be made self-supporting in a reasonable length of time. The Central Market building, built in 1857 and occupied until December 1949, when it was destroyed by fire....The final determination of whether or not a new public retail market should be built in downtown Cleveland to replace Central Market will have to be made by city officials (excerpt from survey summary).https://engagedscholarship.csuohio.edu/clevmembks/1023/thumbnail.jp

    Rydberg Wave Packets are Squeezed States

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    We point out that Rydberg wave packets (and similar ``coherent" molecular packets) are, in general, squeezed states, rather than the more elementary coherent states. This observation allows a more intuitive understanding of their properties; e.g., their revivals.Comment: 7 pages of text plus one figure available in the literature, LA-UR 93-2804, to be published in Quantum Optics, LaTe

    Exact results for `bouncing' Gaussian wave packets

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    We consider time-dependent Gaussian wave packet solutions of the Schrodinger equation (with arbitrary initial central position, x_0, and momentum, p_0, for an otherwise free-particle, but with an infinite wall at x=0, so-called bouncing wave packets. We show how difference or mirror solutions of the form psi(x,t)-psi(-x,t) can, in this case, be normalized exactly, allowing for the evaluation of a number of time-dependent expectation values and other quantities in closed form. For example, we calculate _t explicitly which illustrates how the free-particle kinetic (and hence total) energy is affected by the presence of the distant boundary. We also discuss the time dependence of the expectation values of position, _t, and momentum, _t, and their relation to the impulsive force during the `collision' with the wall. Finally, the x_0,p_0 --> 0 limit is shown to reduce to a special case of a non-standard free-particle Gaussian solution. The addition of this example to the literature then expands on the relatively small number of Gaussian solutions to quantum mechanical problems with familiar classical analogs (free particle, uniform acceleration, harmonic oscillator, unstable oscillator, and uniform magnetic field) available in closed form.Comment: 14 pages, 1 embedded .eps figur

    Acid-Labile Traceless Click Linker for Protein Transduction

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    Intracellular delivery of active proteins presents an interesting approach in research and therapy. We created a protein transduction shuttle based on a new traceless click linker that combines the advantages of click reactions with implementation of reversible pH-sensitive bonds. The azidomethyl-methylmaleic anhydride (AzMMMan) linker was found compatible with different click chemistries, demonstrated in bioreversible protein modification with dyes, polyethylene glycol, or a transduction carrier. Linkages were stable at physiological pH but reversible at the mild acidic pH of endosomes or lysosomes. We show that pH-reversible attachment of a defined endosome-destabilizing three-arm oligo(ethane amino)amide carrier generates an effective shuttle for protein delivery. The cargo protein nlsEGFP, when coupled via the traceless AzMMMan linker, experiences efficient cellular uptake and endosomal escape into the cytosol, followed by import into the nucleus. In contrast, irreversible linkage to the same shuttle hampers nuclear delivery of nlsEGFP which after uptake remains trapped in the cytosol. Successful intracellular delivery of bioactive ß-galactosidase as a model enzyme was also demonstrated using the pH-controlled shuttle system

    The Central Retail Food Market of Cleveland, Ohio

    Get PDF
    A study of the Central Retail Food Market in Cleveland, Ohio was made in 1947 at the request of Mayor Thomas A. Burke (Marketing and Facilities Research Branch 3 of the Production and Marketing Administration, U.S. Department of Agriculture) to determine the public need for a new market. In the previous year the city had voted favorably on a bond issue of $1,000,000 for the relocation and rebuilding of the market, provided it could be made self-supporting in a reasonable length of time. The Central Market building, built in 1857 and occupied until December 1949, when it was destroyed by fire....The final determination of whether or not a new public retail market should be built in downtown Cleveland to replace Central Market will have to be made by city officials (excerpt from survey summary). Original publication date 1951.https://engagedscholarship.csuohio.edu/clevmembks/1023/thumbnail.jp

    The Stark effect in linear potentials

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    We examine the Stark effect (the second-order shift in the energy spectrum due to an external constant force) for two 1-dimensional model quantum mechanical systems described by linear potentials, the so-called quantum bouncer (defined by V(z) = Fz for z>0 and V(z) infinite for z<0) and the symmetric linear potential (given by V(z) = F|z|). We show how straightforward use of the most obvious properties of the Airy function solutions and simple Taylor expansions give closed form results for the Stark shifts in both systems. These exact results are then compared to other approximation techniques, such as perturbation theory and WKB methods. These expressions add to the small number of closed-form descriptions available for the Stark effect in model quantum mechanical systems.Comment: 15 pages. To appear in Eur. J. Phys. Needs Institute of Physics (iopart) style file

    A unitary model for meson-nucleon scattering

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    In an effective Lagrangian model employing the K-matrix approximation we extract nucleon resonance parameters. To this end we analyze simultaneously all available data for reactions involving the final states πN\pi N, ππN\pi\pi N, ηN\eta N and KΛK \Lambda in the energy range mN+mπs1.9m_N + m_{\pi} \le \sqrt s \le 1.9 GeV. The background contributions are generated consistently from the relevant Feynman amplitudes, thus significantly reducing the number of free parameters.Comment: Revised version. 60 pages, 17 figures. Two figures and a short discussion (\pi N \to \eta N, K \Lambda amplitudes) added, typos and minor errors in the citations correcte

    Production, Decay, and Polarization of Excited Heavy Hadrons

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    We discuss the production via fragmentation of excited heavy mesons and baryons, and their subsequent decay. In particular, we consider the question of whether a net polarization of the initial heavy quark may be detected, either in a polarization of the final ground state or in anisotropies in the decay products of the excited hadron. The result hinges in part on a nonperturbative parameter which measures the net transverse alignment of the light degrees of freedom in the fragmentation process. We use existing data on charmed mesons to extract this quantity for certain excited mesons. Using this result, we estimate the polarization retention of charm and bottom baryons.Comment: 37 pages, 3 figures available upon request, uses phyzzx forma
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