2,928 research outputs found

    Enhancing Christian School Experiences for Pre-Service Teachers through Service-Learning Partnerships

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    The mission of the Teacher Licensure Program at Liberty University is to develop competent professionals with a Christian worldview for Christian, public, and private schools. To be consistent with the mission, classroom experience in both Christian and public schools should be required for each teacher candidate who successfully completes Liberty’s program. One of the challenges in the implementation of the mission has been an inadequate number of field experience placements available in Christian school settings

    Lighting the Way with Differentiation in Reading

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    Enhancing Christian School Field Experiences through Academic Coaching in a Service-learning Partnership

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    This article gives an overview of service learning as it relates to learning and understanding a college student’s field of study. A survey was given to our education candidates who were completing a service learning project in a local Christian school. Results from the survey indicate that students were more likely to work in Christian school after having been exposed to this experience

    Remarks on the renormalization of primordial cosmological perturbations

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    We briefly review the need to perform renormalization of inflationary perturbations to properly work out the physical power spectra. We also summarize the basis of (momentum-space) renormalization in curved spacetime and address several misconceptions found in recent literature on this subject.Comment: 5 page

    Relation Between Einstein And Quantum Field Equations

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    We show that there exists a choice of scalar field modes, such that the evolution of the quantum field in the zero-mass and large-mass limits is consistent with the Einstein equations for the background geometry. This choice of modes is also consistent with zero production of these particles and thus corresponds to a preferred vacuum state preserved by the evolution. In the zero-mass limit, we find that the quantum field equation implies the Einstein equation for the scale factor of a radiation-dominated universe; in the large-mass case, it implies the corresponding Einstein equation for a matter-dominated universe. Conversely, if the classical radiation-dominated or matter-dominated Einstein equations hold, there is no production of scalar particles in the zero and large mass limits, respectively. The suppression of particle production in the large mass limit is over and above the expected suppression at large mass. Our results hold for a certain class of conformally ultrastatic background geometries and therefore generalize previous results by one of us for spatially flat Robertson-Walker background geometries. In these geometries, we find that the temporal part of the graviton equations reduces to the temporal equation for a massless minimally coupled scalar field, and therefore the results for massless particle production hold also for gravitons. Within the class of modes we study, we also find that the requirement of zero production of massless scalar particles is not consistent with a non-zero cosmological constant. Possible implications are discussed.Comment: Latex, 24 pages. Minor changes in text from original versio

    Revising the observable consequences of slow-roll inflation

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    We study the generation of primordial perturbations in a (single-field) slow-roll inflationary universe. In momentum space, these (Gaussian) perturbations are characterized by a zero mean and a non-zero variance Δ2(k,t)\Delta^2(k, t). However, in position space the variance diverges in the ultraviolet. The requirement of a finite variance in position space forces one to regularize Δ2(k,t)\Delta^2(k, t). This can (and should) be achieved by proper renormalization in an expanding universe in a unique way. This affects the predicted scalar and tensorial power spectra (evaluated when the modes acquire classical properties) for wavelengths that today are at observable scales. As a consequence, the imprint of slow-roll inflation on the CMB anisotropies is significantly altered. We find a non-trivial change in the consistency condition that relates the tensor-to-scalar ratio rr to the spectral indices. For instance, an exact scale-invariant tensorial power spectrum, nt=0n_t=0, is now compatible with a non-zero ratio r≈0.12±0.06r\approx 0.12\pm0.06, which is forbidden by the standard prediction (r=−8ntr=-8n_t). The influence of relic gravitational waves on the CMB may soon come within the range of planned measurements, offering a non-trivial test of the new predictions.Comment: 24 page

    Magnetic Flux Expulsion in the Powerful Superbubble Explosions and the Alpha-Omega Dynamo

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    The possibility of the magnetic flux expulsion from the Galaxy in the superbubble (SB) explosions, important for the Alpha-Omega dynamo, is considered. Special emphasis is put on the investigation of the downsliding of the matter from the top of the shell formed by the SB explosion which is able to influence the kinematics of the shell. It is shown that either Galactic gravity or the development of the Rayleigh-Taylor instabilities in the shell limit the SB expansion, thus, making impossible magnetic flux expulsion. The effect of the cosmic rays in the shell on the sliding is considered and it is shown that it is negligible compared to Galactic gravity. Thus, the question of possible mechanism of flux expulsion in the Alpha-Omega dynamo remains open.Comment: MNRAS, in press, 11 pages, 9 figure
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