5,666 research outputs found
Media Literacy Education from Kindergarten to College: A Comparison of How Media Literacy Is Addressed across the Educational System
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
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
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
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
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
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
We consider the lagrangian 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. is
scale-invariant for F = c_1 R\sp {k+1} and a divergence for . The
field equation is scale-invariant not only for the sum of them, but also for
. 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 . More generally: Let be
a divergence and a scale-invariant lagrangian, then 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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Photon-electron coincidence experiments at synchrotron radiation facilities with arbitrary bunch modes
We report the adaptation of an electron–photon coincidence detection scheme to the multibunch hybrid mode of the synchrotron radiation source BESSY II (Helmholtz-Zentrum Berlin). Single-event-based data acquisition and evaluation, combined with the use of relative detection times between the coincident particles, enable the acquisition of proper coincidence signals from a quasi-continuous excitation pattern. The background signal produced by accidental coincidences in the time difference representation is modeled using the non-coincident electron and photon spectra. We validate the method by reproducing previously published results, which were obtained in the single bunch mode, and illustrate its usability for the multibunch hybrid mode by investigating the photoionization of CO2 into CO+2 B satellite states, followed by subsequent photon emission. The radiative lifetime obtained and the electron binding energy are in good agreement with earlier publications. We expect this method to be a useful tool to extend the versatility of coincident particle detection to arbitrary operation modes of synchrotron radiation facilities and other excitation sources without the need for additional experimental adjustments
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