8,818 research outputs found
Educating Seth: An Ecosophical Conversation
Most accounts of human activity have a particular structure that supports the accounting. Education as a human activity has over centuries, and particularly in the past century, developed a narrative structure that, while seemingly "neutral", privileges accounts of a certain kind. The authors suggest that if ecosophical education is to find a presence in today's schools, the now dominant narrative structure needs to be challenged. By revealing an alternate narrative structure embodied in the particularities of a grade 4 classroom, the authors hope that such a narrative structure can provide ecosophical education with an authentic home in today's schools
The Impact of a Summer Workshop: Staff Orientation at Mesa Community College
The Arizona Collaborative for Excellence in the Preparation of Teachers (ACEPT) is a National Science Foundation (NSF) funded project to reform teacher preparation in Arizona. One of the major modes for initiating both collaboration and reform between and among university and community college staff has been the Summer Faculty Enhancement Workshops developed and offered by ACEPT co-principal investigators each summer since 1996. The summer of 1999 featured five workshops, one of which was the Geology Summer Workshop which brought participants into close contact with eighteen reformed practices appropriate for large lecture style classes. One of the nineteen participants was Ray Grant, Department of Science Chair at Mesa Community College, one of the collaborating institutions in ACEPT. This report describes what Ray, as department chair, did as a follow-up to the summer workshop. What occurred completely transformed the Department of Science staff orientation meeting held just prior to the fall semester. Some of the surprising events are described in this report. The transformation of the staff meeting not only speaks to the impact of the Geology Summer Workshop, but also suggests creative roles for staff orientation meetings in community college settings
Gigantic Enhancement of Magneto-Chiral Effect in Photonic Crystals
We theoretically propose a method to enhance dramatically a
magneto-chiral(MC) effect by using the photonic crystals composed of a
multiferroic material. The MC effect, the directional birefringence even for
unpolarized light, is so small that it has been difficult to observe
experimentally. Two kinds of periodic structures are investigated; (a) a
multilayer and (b) a stripe composed of a magneto-chiral material and air. In
both cases, the difference in reflectivity between different magnetization
directions is enhanced by a factor of hundreds compared with a bulk material.Comment: 3 pages, 3 figure
Getting the most out of a post-column EELS spectrometer on a TEM/STEM by optimising the optical coupling
Ray tracing is used to find improved set-ups of the projector system of a JEOL ARM 200CF TEM/STEM for use in coupling it to a Gatan 965 Quantum ER EELS system and to explain their performance. The system has a probe aberration corrector but no image corrector. With the latter, the problem would be more challenging. The agreement between the calculated performance and that found experimentally is excellent. At 200kV and using the 2.5mm Quantum entrance aperture, the energy range over which the collection angle changes by a maximum of 5% from that at zero loss has been increased from 1.2keV to 4.7keV. At lower accelerating voltages, these energy ranges are lower e.g. at 80kV they are 0.5keV and 2.0keV respectively. The key factors giving the improvement are an increase in the energy-loss at which the projector cross-over goes to infinity and a reduction of the combination aberrations that occur in a lens stack. As well as improving the energy-loss range, the new set-ups reduce spectrum artefacts and minimise the motion of the diffraction pattern at low STEM magnification for electrons that have lost energy. Even if making the pivot points conjugate with the film plane gives no motion for zero-loss electrons, there will be motion for those electrons that have lost energy, leading to a false sense of security when performing spectrum imaging at low magnifications. De-scanning of the probe after the objective lens is a better way of dealing with this problem
Comment on "White-Noise-Induced Transport in Periodic Structures"
In the paper by J.\L uczka {\em et al.} ({\em Europhys. Lett.}, {\bf 31}
(1995) 431), the authors reported by rigorous calculation that an additive
Poissonian white shot noise can induce a macroscopic current of a dissipative
particle in a periodic potential -- even {\em in the absence} of spatial
asymmetry of the potential. We argue that their main result is an obvious one
caused by the spatially broken symmetry of a probability distribution of the
additive noise, unlike the similar result caused by chaotic noise which has a
symmetric probability distribution ({\em J.Phys.Soc.Jpn.}, {\bf 63} (1994)
2014).Comment: 2 pages (Latex); submitted to Europhys.Let
Syntactic View of Sigma-Tau Generation of Permutations
We give a syntactic view of the Sawada-Williams -generation of
permutations. The corresponding sequence of -operations, of length
is shown to be highly compressible: it has bit
description. Using this compact description we design fast algorithms for
ranking and unranking permutations.Comment: accepted on LATA201
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