73,026 research outputs found

    Racial Intelligence Testing and the Mexican People

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    In the 1920s and 1930s the Mexican school age population increasingly participated in the educational system of the US. Meanwhile, many first experiences of these children with the state came in the form of educational research. The intelligence testing movement had a brief history before then, one which was gathering much momentum and greatly encouraged by corporate foundations and the cooperation of university administrations. The rapid immigration in the 1920s and settlement of Mexicans into colonias of the Southwest coincided with the rise of academic research and publications on racial intelligence as well as with the combination of mass compulsory education and intelligence testing tracking and curriculum differentation [differentiation]

    Computer program for predicting symmetric jet mixing of compressible flow in jets

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    Finite-difference computer program has been developed for treating mixing of two parallel and compressible air streams; one of them may be supersonic. This development is restricted to symmetric jet mixing in which high-speed jet is located on axis of channel and no provision is made for blowing or suction along channel walls

    An analytical sensitivity method for use in integrated aeroservoelastic aircraft design

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    Interdisciplinary analysis capabilities have been developed for aeroservoelastic aircraft and large flexible spacecraft, but the requisite integrated design methods are only beginning to be developed. One integrated design method which has received attention is based on hierarchal problem decompositions, optimization, and design sensitivity analyses. This paper highlights a design sensitivity analysis method for Linear Quadratic Gaussian (LQG) optimal control laws, enabling the use of LQG techniques in the hierarchal design methodology. The LQG sensitivity analysis method calculates the change in the optimal control law and resulting controlled system responses due to changes in fixed design integration parameters using analytical sensitivity equations. Numerical results of a LQG design sensitivity analysis for a realistic aeroservoelastic aircraft example are presented. In this example, the sensitivity of the optimal control law and aircraft response for various parameters such as wing bending natural frequency is determined. The sensitivity results computed from the analytical expressions are used to estimate changes in response resulting from changes in the parameters. Comparisons of the estimates with exact calculated responses show they are reasonably accurate for + or - 15 percent changes in the parameters. Evaluation of the analytical expressions is computationally faster than equivalent finite difference calculations

    A preliminary annotated checklist and evaluation of the diversity of the Chrysomelidae (Coleoptera) of the Baja California peninsula, Mexico

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    A preliminary annotated checklist of the Chrysomelidae of the Baja California peninsula, Mexico is presented based on literature records and the examination of approximately 16,000 chrysomelid specimens. Seven subfamilies and 218 described species have been identified. Ninty-one species are recognized from the Baja California peninsula for the first time. Twenty-nine species are listed as endemic. An additional 128 morphospecies have been identified as undescribed or not yet associated with described species of mainland Mexico or the United States. Adult host plant associations have been identified for approximately 120 species or 35% of the leaf beetle fauna of the region. Each of the 218 described species is associated with the eight plant communities as outlined by Wiggins (1980). Two dominant subfamilies comprise 76% of the leaf beetle fauna: Galerucinae, 87 species (40%) and Cryptocephalinae, 78 species (36%). The following new combinations are proposed: Neolema californica (Heinze, 1927), transferred from Lema Fabricius, 1798; Pseudoluperus histrio (Horn, 1895), transferred from Keitheatus Wilcox, 1965, and Diachus peninsularis (Schaeffer, 1906), transferred from Triachus J. L. LeConte, 1880. Lema peninsulae Crotch, 1873, is removed from synonymy with L. balteata J. L. LeConte, 1884 and reinstated as a valid species. A replacement name is proposed: Longitarsus bajaensis Andrews and Gilbert for Longitarsus bicolor Horn, 1894

    Domain discovery method for topological profile searches in protein structures

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    We describe a method for automated domain discovery for topological profile searches in protein structures. The method is used in a system TOPStructure for fast prediction of CATH classification for protein structures (given as PDB files). It is important for profile searches in multi-domain proteins, for which the profile method by itself tends to perform poorly. We also present an O(C(n)k +nk2) time algorithm for this problem, compared to the O(C(n)k +(nk)2) time used by a trivial algorithm (where n is the length of the structure, k is the number of profiles and C(n) is the time needed to check for a presence of a given motif in a structure of length n). This method has been developed and is currently used for TOPS representations of protein structures and prediction of CATH classification, but may be applied to other graph-based representations of protein or RNA structures and/or other prediction problems. A protein structure prediction system incorporating the domain discovery method is available at http://bioinf.mii.lu.lv/tops/

    Inviscid Flow Field Effects: Experimental results

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    The aero-optical distortions due to invisid flow effects over airborne laser turrets is investigated. Optical path differences across laser turret apertures are estimated from two data sources. The first is a theoretical study of main flow effects for a spherical turret assembly for a Mach number (M) of 0.6. The second source is an actual wind tunnel density field measurement on a 0.3 scale laser turret/fairing assembly, with M = 0.75. A range of azimuthal angles from 0 to 90 deg was considered, while the elevation angle was always 0 deg (i.e., in the plane of the flow). The calculated optical path differences for these two markedly different geometries are of the same order. Scaling of results to sea level conditions and an aperture diameter of 50 cm indicated up to 0.0007 cm of phase variation across the aperture for certain forward look angles and a focal length of F = -11.1 km. These values are second order for a 10.6 micron system
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