5,666 research outputs found

    Media Literacy Education from Kindergarten to College: A Comparison of How Media Literacy Is Addressed across the Educational System

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    This study of media literacy education at all levels of the educational system considered faculty perceptions of student media literacy competencies, the extent to which media literacy is addressed in class, and the extent to which faculty members consider media literacy education to be important. Data suggest that despite the research and policy focus on media literacy at the K-12 level, educators reported addressing media literacy competencies most frequently within higher education. Results also suggested that training and experience, not youth or digital nativity, are the factors that lead to an interest in teaching about media literacy among faculty

    Helping Students Understand Media: Examining the Efficacy of Interdisciplinary Media Training at the University Level

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    Crowded curriculums and restrictive program requirements often mean that comprehensive media literacy education is impractical at the university level, and that media literacy competencies can be addressed only in the form of narrowly focused lessons integrated into existing classes. This study considers the extent to which such limited lessons can lead to the development of broader, well-rounded media literacy competencies. Data gathered from a quasi-experiment involving 118 participants suggests that narrowly focused media lessons can be used to encourage the development of broader media literacy competencies, but that focused instruction remains necessary as well

    Vacuum solutions which cannot be written in diagonal form

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    A vacuum solution of the Einstein gravitational field equation is given that follows from a general ansatz but fails to follow from it if a certain symmetric matrix is assumed to be in diagonal form from the beginning.Comment: 18 pages, latex, no figures. An Acknowledgement, 4 references, and the section "Note added" are adde

    A Distributed Multimedia Communication System and its Applications to E-Learning

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    In this paper we report on a multimedia communication system including a VCoIP (Video Conferencing over IP) software with a distributed architecture and its applications for teaching scenarios. It is a simple, ready-to-use scheme for distributed presenting, recording and streaming multimedia content. We also introduce and investigate concepts and experiments to IPv6 user and session mobility, with the special focus on real-time video group communication.Comment: Including 6 figure

    The tetralogy of Birkhoff theorems

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    We classify the existent Birkhoff-type theorems into four classes: First, in field theory, the theorem states the absence of helicity 0- and spin 0-parts of the gravitational field. Second, in relativistic astrophysics, it is the statement that the gravitational far-field of a spherically symmetric star carries, apart from its mass, no information about the star; therefore, a radially oscillating star has a static gravitational far-field. Third, in mathematical physics, Birkhoff's theorem reads: up to singular exceptions of measure zero, the spherically symmetric solutions of Einstein's vacuum field equation with Lambda = 0 can be expressed by the Schwarzschild metric; for Lambda unequal 0, it is the Schwarzschild-de Sitter metric instead. Fourth, in differential geometry, any statement of the type: every member of a family of pseudo-Riemannian space-times has more isometries than expected from the original metric ansatz, carries the name Birkhoff-type theorem. Within the fourth of these classes we present some new results with further values of dimension and signature of the related spaces; including them are some counterexamples: families of space-times where no Birkhoff-type theorem is valid. These counterexamples further confirm the conjecture, that the Birkhoff-type theorems have their origin in the property, that the two eigenvalues of the Ricci tensor of two-dimensional pseudo-Riemannian spaces always coincide, a property not having an analogy in higher dimensions. Hence, Birkhoff-type theorems exist only for those physical situations which are reducible to two dimensions.Comment: 26 pages, updated references, minor text changes, accepted by Gen. Relat. Gra

    Spectroscopic characterization of reaction centers of the (M)Y210W mutant of the photosynthetic bacterium Rhodobacter sphaeroides

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    The tyrosine-(M)210 of the reaction center of Rhodobacter sphaeroides 2.4.1 has been changed to a tryptophan using site-directed mutagenesis. The reaction center of this mutant has been characterized by low-temperature absorption and fluorescence spectroscopy, time-resolved sub-picosecond spectroscopy, and magnetic resonance spectroscopy. The charge separation process showed bi-exponential kinetics at room temperature, with a main time constant of 36 ps and an additional fast time constant of 5.1 ps. Temperature dependent fluorescence measurements predict that the lifetime of P* becomes 4–5 times slower at cryogenic temperatures. From EPR and absorbance-detected magnetic resonance (ADMR, LD-ADMR) we conclude that the dimeric structure of P is not significantly changed upon mutation. In contrast, the interaction of the accessory bacteriochlorophyll BA with its environment appears to be altered, possibly because of a change in its position

    Two-dimensional higher-derivative gravity and conformal transformations

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    We consider the lagrangian L=F(R)L=F(R) in classical (=non-quantized) two-dimensional fourth-order gravity and give new relations to Einstein's theory with a non-minimally coupled scalar field. We distinguish between scale-invariant lagrangians and scale-invariant field equations. LL is scale-invariant for F = c_1 R\sp {k+1} and a divergence for F=c2RF=c_2 R. The field equation is scale-invariant not only for the sum of them, but also for F=RlnRF=R\ln R. We prove this to be the only exception and show in which sense it is the limit of \frac{1}{k} R\sp{k+1} as k0k\to 0. More generally: Let HH be a divergence and FF a scale-invariant lagrangian, then L=HlnFL= H\ln F has a scale-invariant field equation. Further, we comment on the known generalized Birkhoff theorem and exact solutions including black holes.Comment: 16 pages, latex, no figures, [email protected], Class. Quant. Grav. to appea
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