3,945 research outputs found
An Unfinished Canvas: Teacher Preparation, Instructional Delivery, and Professional Development in the Arts
Based on surveys, interviews, and secondary data analyses, identifies deficiencies in teacher preparation, instruction, and development in the arts in California, and recommends minimum training requirements and support for professional development
Spherical harmonic representation of the main geomagnetic field for world charting and investigations of some fundamental problems of physics and geophysics
Quiet-day data from MAGSAT were examined for effects which might test the validity of Maxwell's equations. Both external and toroidal fields which might represent a violation of the equations appear to exist, well within the associated errors. The external field might be associated with the ring current, and varies of a time-scale of one day or less. Its orientation is parallel to the geomagnetic dipole. The toriodal field can be confused with an orientation in error (in yaw). It the toroidal field really exists, its can be related to either ionospheric currents, or to toroidal fields in the Earth's core in accordance with Einstein's unified field theory, or to both
Development and application of operational techniques for the inventory and monitoring of resources and uses for the Texas coastal zone. Volume 2: Appendices
There are no author-identified significant results in this report
Two Examples of Circular Motion for Introductory Courses in Relativity
The circular twin paradox and Thomas Precession are presented in a way that
makes both accessible to students in introductory relativity courses. Both are
discussed by examining what happens during travel around a polygon and then in
the limit as the polygon tends to a circle. Since relativistic predictions
based on these examples can be verified in experiments with macroscopic objects
such as atomic clocks and the gyroscopes on Gravity Probe B, they are
particularly convincing to introductory students.Comment: Accepted by the American Journal of Physics This version includes
revision
Development and Application of Operational Techniques for the Inventory and Monitoring of Resources and Uses for the Texas Coastal Zone
There are no author-identified significant results in this report
Development and application of operational techniques for the inventory and monitoring of resources and uses for the Texas coastal zone
The author has identified the following significant results. Four LANDSAT scenes were analyzed for the Harbor Island area test sites to produce land cover and land use maps using both image interpretation and computer-assisted techniques. When evaluated against aerial photography, the mean accuracy for three scenes was 84% for the image interpretation product and 62% for the computer-assisted classification maps. Analysis of the fourth scene was not completed using the image interpretation technique, because of poor quality, false color composite, but was available from the computer technique. Preliminary results indicate that these LANDSAT products can be applied to a variety of planning and management activities in the Texas coastal zone
Spherical harmonic representation of the main geomagnetic field for world charting and investigations of some fundamental problems of physics and geophysics
The data processing of MAGSAT investigator B test tapes and data tapes, and tapes of selected data on 15 magnetically quiet days is reported. The 1980 World Chart spherical model was compared with the MAGSAT (3/80) and MAGSAT vector data were used in the models. An article on modelling the geomagnetic field using satellite data is included
Climatic variations on Mars: 2. Evolution of carbon dioxide atmosphere and polar caps
The long-term variations in the atmospheric pressure and the polar cap temperature of Mars resulting from the obliquity oscillations (presented by W. R. Ward, 1974) are discussed. In performing these calculations, the assumption is made that the atmosphere is in equilibrium with perennial CO_2 ice deposits at the north pole, as is proposed by R. B. Leighton and B. C. Murray (1966). If heat transport by the atmosphere is neglected, the temperature of CO_2 ice at the poles ranges from ∼130°K to ∼160°K, the corresponding atmospheric pressure rising from a few tenths of a millibar to ∼30 mbar, respectively. The neglect of atmospheric heat transport probably underestimates the peak pressure. Because the altitude of the south cap is ∼2 km higher than that of the north cap, CO_2 ice is unstable there and will migrate to the north cap at a rate ∼10 g/cm^2 yr, the implication being that the south residual cap is water ice. A simplified model of the annual polar caps and pressure fluctuations is also presented. This indicates that when the obliquity is at its maximum, the annual caps may be greatly enlarged in both mass and maximum coverage. The modifications introduced by including significant atmospheric heat transport are then discussed. Finally, the implications of different past climatic conditions on the mechanism of eolian erosion are briefly considered
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