The effects of precision teaching and self-regulation learning on early multiplication fluency

Fluent recall of basic facts is essential to the development of more complex math skills. Therefore, failure to develop fluency with basic facts may impede the development of these skills. The present study used a between groups experimental design to investigate whether a basic facts fluency program, implemented within a self-regulated learner (SRL) framework, could lead to increased fluency with multiplication facts for Year 5 and Year 6 New Zealand students (9–10 years old). This study also investigated the extent to which the SRL program altered students’ basic facts practice behavior outside of school hours. The study found that the SRL program resulted in rapid fluency development that was maintained over time. Nomothetic and idiographic analysis confirmed that the program was suitable for use within Tier 1 of the response to intervention framework. In addition, the study also found that students who received the program altered their practice behavior outside school hours. The results from this study show how elements of self-regulated learning and precision teaching can be successfully combined to enhance students’ mathematics achievement

Hydrotalcites and hydrated Mg-carbonates as carbon sinks in serpentinite mineral wastes from the Woodsreef chrysotile mine, New South Wales, Australia: Controls on carbonate mineralogy and efficiency of CO2 air capture in mine tailings

Carbon mineralisation of ultramafic mine tailings can reduce net emissions of anthropogenic carbon dioxide by reacting Mg-silicate and hydroxide minerals with atmospheric CO2 to produce carbonate minerals. We investigate the controls on carbonate mineral formation at the derelict Woodsreef chrysotile mine (New South Wales, Australia). Quantitative XRD was used to understand how mineralogy changes with depth into the tailings pile, and shows that hydromagnesite [Mg5(CO3)4(OH)2·4H2O], is present in shallow tailings material (<40?cm), while coalingite [Mg10Fe3+2(CO3)(OH)24·2H2O] and pyroaurite [Mg6Fe3+2(CO3)(OH)16·4H2O] are forming deeper in the tailings material. This indicates that there may be two geochemical environments within the upper ~1?m of the tailings, with hydromagnesite forming within the shallow tailings via carbonation of brucite in CO2-rich conditions, and pyroaurite and coalingite forming under more carbon limited conditions at depth. Radiogenic isotope results indicate hydromagnesite and pyroaurite have a modern (F14C > 0.8) atmospheric CO2 source. Laboratory-based anion exchange experiments, conducted to explore stable C isotope fractionation in pyroaurite, shows that pyroaurite d13C values change with carbon availability, and 13C-depleted signatures are typical of hydrotalcites in C-limited environments, such as the deep tailings at Woodsreef. Quantitative XRD and elemental C data estimates that Woodsreef absorbs between of 229.0–405.1?g CO2?m-2 y-1

Carbon accounting of mined landscapes, and deployment of a geochemical treatment system for enhanced weathering at Woodsreef Chrysotile Mine, NSW, Australia

Carbonation of ultramafic mine tailings has the potential to offset greenhouse gas emissions from mining by trapping CO within the crystal structures of Mg-carbonate minerals and hydrotalcite supergroup minerals, which form as weathering products in tailings storage facilities. Here, we present a detailed geochemical and mineralogical assessment of tailings from the Woodsreef Chrysotile Mine, New South Wales, Australia, demonstrating that coupling mineralogical and elemental datasets improves the accuracy of carbon accounting in mined landscapes. Detailed analysis of tailings mineralogy using quantitative X-ray diffraction (XRD) and total carbon analyses reveals that previous assessments of passive mineral carbonation at Woodsreef have been underestimated. Maximum values for the abundance of total carbon (up to 0.4 wt%), as well as the abundances of secondary carbonate minerals (i.e., up to 1.9 wt% hydromagnesite and up to 2.6 wt% pyroaurite, measured with XRD) are observed between approximately 2 cm and 30 cm depth in profiles collected within experimental plots. However, an amorphous Mg-carbonate phase, that cannot be detected using XRD, is also present at comparably high abundances to depths of at least 1 m. This phase is readily observed using scanning electron microscopy, it contributes a measured carbon content of approximately 0.2 wt% at up to 1 m depth, and it has a predominantly atmospheric carbon isotopic signature (FC > 0.80). We find that using only XRD data results in the sequestered CO being underestimated by nearly four times compared to estimates incorporating total carbon measurements, highlighting the important role of amorphous Mg-carbonates in the carbon cycles of mines. Combining XRD and total carbon data, we provide an estimate for passive carbon sequestration by both crystalline and amorphous carbonates in the Woodsreef tailings (11.7 kg CO/m considering the upper 1 m) and suggest that future studies should employ both XRD and total carbon measurements for carbon accounting. The Woodsreef Chrysotile Mine was also the test site for a field-based geochemical treatment system designed to promote mineral carbonation. A solar powered, independently operating geochemical treatment system is designed and deployed to deliver controlled acid (0.08 M HSO) or water leaching treatments, and maintain soil pore saturation within optimal levels (approximately 18–36%) to enhance the weathering rate of mine tailings. While the applied treatment did not accelerate capture and mineralisation of CO from air, it could be coupled to technologies that enhance the supply of CO for mineral carbonation. We apply our new strategy for carbon accounting to this experimental site in order to assess changes in mineralogy and the spatial scale on which carbon accounting must be done to accurately measure carbon sequestered during weathering of ultramafic rock. Our work provides important lessons and context for future trials of accelerated tailings dissolution and mineral carbonation, which will benefit the next stage of development in the scale-up of this technology