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Recent studies of elementary teachers' knowledge about reading have been built on the premise that teachers need thorough knowledge about language and reading processes, but these studies have provided only limited evidence that teachers' performance on tests of such knowledge contributes to their students' reading achievement. The present study was designed to examine the contribution of first-through third-grade teachers' knowledge about early reading to their students' improvement on tests of word analysis and reading comprehension, controlling for socio-demographic characteristics of students, their prior reading achievement, and teachers' educational attainment, professional experiences, and socio-demographic characteristics. Preliminary analyses indicated that the test of teachers' knowledge had adequate psychometric characteristics. However, performance on this measure of teachers' knowledge did not significantly explain students' improvement on the two reading subtests. The complexity of the factors that influence teachers' knowledge acquisition and the context in which the study was carried out offer possible explanations for these results. In addition, teachers' content knowledge about reading might not be closely associated with the practices they use in reading instruction, and therefore might not be significantly related to their students' improvement in reading over a year.Keywords Reading Á Elementary Á Teacher knowledge Á Reading achievement Purpose of the studyThe federal goal of improving the quality of teaching (U.S. Department of Education, 2002b) has made it critical that there be means of identifying more and Order of authors is alphabetical.

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To study the effect of car body-mounted equipment on the car body flexible vibration, a vertical rigid-flexible coupling model of a high-speed vehicle is established, which includes a flexible car body, rigid bodies for two bogie frames, four wheelsets, and the car body-mounted equipment. The car body is approximated by an elastic beam, with dimensions selected to give similar mass and vertical bending frequency to an existing car body. Model validation is then carried out by comparing results from numerical simulation and on-track test. Using frequency response analysis and ride comfort analysis, parametric studies are undertaken in order to investigate the respective effect of equipment mounting systems on the car body flexible vibration and ride comfort perceived by the passenger. It is found that the equipment behaves as a dynamic vibration absorber on account of its elastic connections to the car body. The stiffness, damping, mass, and installing position of the equipment have a significant influence on the car body flexible vibration. The optimal parameters of the dynamic vibration absorber are given, which can contribute much to the vibration absorption of the car body flexible vibration. Finally, extensive tests on a high-speed test vehicle are conducted to represent a part of results obtained in the numerical study, including modal tests on the car body, component tests on rubber springs used in the equipment mounting systems, and roller rig tests on the vibration absorption performance of the equipment. It is shown that the car body flexible vibration can be effectively suppressed by reasonably suspending the car body-mounted equipment.

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