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  1. Free, publicly-accessible full text available May 1, 2025
  2. Free, publicly-accessible full text available May 1, 2025
  3. To use robots within early childhood education requires the preparation of early childhood teachers to use and teach block-based programming. We used a hierarchical linear model approach to address our research question: How can study cohort, cognitive challenge types, and motivational challenge types be used to predict lesson plan quality? Positive motivational challenge predictors were task value of programming, task value of teaching, mastery goals of programming, belonging in teaching, and autonomy in robotics. Negative motivational challenge predictors were mastery goals of teaching, belonging in robotics, self-efficacy in teaching, autonomy in programming, and autonomy in teaching. Positive cognitive challenge predictors were technical issues, problem solving - higher-order skills, and lesson design - other issues. 
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  4. Abstract

    Uranium (U) is an important global energy resource and a redox sensitive trace element that reflects changing environmental conditions and geochemical cycling. The redox evolution of U mineral chemistry can be interrogated to understand the formation and distribution of U deposits and the redox processes involved in U geochemistry throughout Earth history. In this study, geochemical modeling using thermodynamic data, and mineral chemistry network analysis are used to investigate U geochemistry and deposition through time. The number of U6+mineral localities surpasses the number of U4+mineral localities in the Paleoproterozoic. Moreover, the number of sedimentary U6+mineral localities increases earlier in the Phanerozoic than the number of U4+sedimentary mineral localities, likely due to the necessity of sufficient sedimentary organic matter to reduce U6+–U4+. Indeed, modeling calculations indicate that increased oxidative weathering due to surface oxygenation limited U4+uraninite (UO2) formation from weathered granite and basalt. Louvain network community detection shows that U6+forms minerals with many more shared elements and redox states than U4+. The range of weighted Mineral Element Electronegativity Coefficient of Variation (wMEECV) values of U6+minerals increases through time, particularly during the Phanerozoic. Conversely, the range of wMEECVvalues of U4+minerals is consistent through time due to the relative abundance of uraninite, coffinite, and brannerite. The late oxidation and formation of U6+minerals compared to S6+minerals illustrates the importance of the development of land plants, organic matter deposition, and redox‐controlled U deposition from ground water in continental sediments during this time‐period.

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  5. Chinn, C. ; Tan, E. ; Chan, C. ; Kali, Y (Ed.)