82,167 research outputs found

    School Grades: Identifying Albert's Best Public Schools

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    The study identifies which Alberta elementary schools are worthy of emulation, as well as those where large improvements are possible, by removing the influence of local socio-economic factors on a school's performance.social policy, education, Alberta

    Capillary forces in the acoustics of patchy-saturated porous media

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    A linearized theory of the acoustics of porous elastic formations, such as rocks, saturated with two different viscous fluids is generalized to take into account a pressure discontinuity across the fluid boundaries. The latter can arise due to the surface tension of the membrane separating the fluids. We show that the frequency-dependent bulk modulus K~(ω)\tilde{K}(\omega) for wave lengths longer than the characteristic structural dimensions of the fluid patches has a similar analytic behavior as in the case of a vanishing membrane stiffness and depends on the same parameters of the fluid-distribution topology. The effect of the capillary stiffness can be accounted by renormalizing the coefficients of the leading terms in the low-frequency asymptotic of K~(ω)\tilde{K}(\omega).Comment: 27 pages, 3 figure

    Valencies of the lanthanides

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    The valencies of the lanthanides vary more than was once thought. In addition to valencies associated with a half-full shell, there are valencies associated with a quarter- and three-quarter-full shell. This can be explained on the basis of Slater’s theory of many-electron atoms. The same theory explains the variation in complexing constants in the trivalent state (the “tetrad effect”). Valency in metallic and organometallic compounds is also discussed
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