11,275 research outputs found
Advancing the REVOLUTION: Using Earth Systems Science to Prepare Elementary School Teachers in an Urban Environment
This article describes an Earth Systems approach that was developed to prepare preservice elementary school teachers in understanding science content and pedagogy with emphases in technology and mathematics. This approach, developed at the University of New Orleans, uses Lake Ponchartrain as the unifying theme for four courses in which students learn both scientific content and process. The authors note that many children decide if they like or dislike science by middle school and that improvements in science teaching in the middle grades are imperative, and that improving elementary science education is especially important in regions where significant portions of the student body are from groups traditionally under-represented in science. Surveying and field-testing results suggest that participants in these classes are likely to apply this approach to science teaching in their own classrooms. Educational levels: Graduate or professional
On strongly nonlinear vortex/wave interactions in boundary-layer transition
The interactions between longitudinal vortices and accompanying waves considered are strongly nonlinear, in the sense that the mean-flow profile throughout the boundary layer is completely altered from its original undisturbed state. Nonlinear interactions between vortex flow and Tollmien-Schlichting waves are addressed first, and some analytical and computational properties are described. These include the possibility in the spatial-development case of a finite-distance break-up, inducing a singularity in the displacement thickness. Second, vortex/Rayleigh wave nonlinear interactions are considered for the compressible boundary-layer, along with certain special cases of interest and some possible solution properties. Both types, vortex/Tollmien-Schlichting and vortex/Rayleigh, are short-scale/long-scale interactions and they have potential applications to many flows at high Reynolds numbers. The strongly nonlinear nature is believed to make them very relevant to fully fledged transition to turbulence
Measuring the impact of computer resource quality on the software development process and product
The availability and quality of computer resources during the software development process was speculated to have measurable, significant impact on the efficiency of the development process and the quality of the resulting product. Environment components such as the types of tools, machine responsiveness, and quantity of direct access storage may play a major role in the effort to produce the product and in its subsequent quality as measured by factors such as reliability and ease of maintenance. During the past six years, the NASA Goddard Space Flight Center has conducted experiments with software projects in an attempt to better understand the impact of software development methodologies, environments, and general technologies on the software process and product. Data was extracted and examined from nearly 50 software development projects. All were related to support of satellite flight dynamics ground-based computations. The relationship between computer resources and the software development process and product as exemplified by the subject NASA data was examined. Based upon the results, a number of computer resource-related implications are provided
On the independence of blocks of generalized inverses of bordered matrices
AbstractNecessary and sufficient conditions are given for the blocks in the (1)-, (1,3)-, and (1,4)-inverses of a general bordered matrix to be independent of each other
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