University of Missouri

About: University of Missouri is a education organization based out in Columbia, Missouri, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 41427 authors who have published 83598 publications receiving 2911437 citations. The organization is also known as: Mizzou & Missouri-Columbia.

Beginning teachers : Beliefs and classroom actions

Abstract: The current national priority for systemic approaches to the reform of science and mathematics education has led to unprecedented interest in research on the efficacy of science and mathematics teacher preparation programs. In response to this priority, a focus on collaborative approaches to educational reform and to research on educational reform resulted in a national collaborative research consortium of insitutions of higher education. The consortium was formed to investigate the following question about secondary science teacher education: What are the perceptions, beliefs, and classroom performances of beginning secondary teachers as related to their philosophies of teaching and their content pedagogical skills? The research design and instrumentation yielded detailed descriptions that elicited knowledge and beliefs held by beginning teachers about science, the nature of teaching and learning, and their philosophy of teaching. An analysis of video portfolios of beginning teachers provided classroom-based evidence of their performance in both subject matter and pedagogical dimensions of teaching. Among the findings from this 3-year exploratory study were that teachers graduated from their teacher preparation programs with a range of knowledge and beliefs about: how teachers should interact with subject content and processes, what teachers should be doing in the classroom, what students should be doing in the classroom, philosophies of teaching, and how they perceived themselves as classroom teachers. Beginning teachers described their practices as very student-centered. Observations of these teaching practices contrasted starkly with teacher beliefs: While teachers professed student-centered beliefs, they behaved in teacher-centered ways. Undertaking intensive, collaborative studies such as the one described in this article, is the beginning of efforts through which the science and mathematics education communities can strive to address the needs of students, teachers, teacher educators, and other stakeholders working to establish a common vision for excellent instruction and systemic, long-lasting reform. © 1999 John Wiley & Sons, Inc. J Res Sci Teach 36: 930–954, 1999

Oocyte aging: cellular and molecular changes, developmental potential and reversal possibility

Abstract: In humans, normal healthy children are regularly produced through fertilization of fresh oocytes with fresh spermatozoa.However, asynchrony between oocytes and spermatozoa, especially when aged oocytes are fertilized by fresh or senescent spermatozoa,will not only affect the rate of fertilization and pre- and post-implantation embryo development but also the life of the offspring. As manyfailures in assisted reproduction technologies (ART) are related to oocyte aging, new methods are needed to control oocyte aging to benefitmodern ART.

Synthesis of Pd Nanocrystals Enclosed by {100} Facets and with Sizes < 10 nm for Application in CO Oxidation

Abstract: The catalytic activity of noble-metal nanocrystals is mainly determined by their sizes and the facets exposed on the surface. For single crystals, it has been demonstrated that the Pd(100) surface is catalytically more active than both Pd(110) and Pd(111) surfaces for the CO oxidation reaction. Here we report the synthesis of Pd nanocrystals enclosed by {100} facets with controllable sizes in the range of 6–18 nm by manipulating the rate of reduction of the precursor. UV-vis spectroscopy studies indicate that the rate of reduction of Na2PdCl4 can be controlled by adjusting the concentrations of Br− and Cl− ions added to the reaction mixture. Pd nanocrystals with different sizes were immobilized on ZnO nanowires and evaluated as catalysts for CO oxidation. We found that the activity of this catalytic system for CO oxidation showed a strong dependence on the nanocrystal size. When the size of the Pd nanocrystals was reduced from 18 nm to 6 nm, the maximum conversion rate was significantly enhanced by a factor of ∼10 and the corresponding maximum conversion temperature was lowered by ∼80 °C.

Experimental and simulation studies of the coaxially fed U-slot rectangular patch antenna

Abstract: Experimental and simulation results are presented on the coaxially fed rectangular patch antenna with a U-shaped slot. Experimental results include impedance bandwidth, copolar- and crosspolar-pattern characteristics and gain measurements. Simulation results are obtained mainly through the development of a FDTD code. It is found that the U-slot patch on a foam substrate of about 0.08/spl lambda/ thick can be designed to attain 20-30% impedance as well as gain bandwidths without the need of parasitic patches on another layer or on the same layer. The far-field patterns have good copolar and crosspolar characteristics. By altering the patch width or feed position, the wideband characteristic can be changed into a dual-frequency characteristic. Simulation results are in good agreement with measurements.