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In this meta-analysis of 54 longitudinal studies with over 58,000 students in kindergarten through 12th grade, we examined the predictive nature of early numeracy measured at or before the first year of formal schooling in relation to later mathematics. Results showed that early numeracy significantly predicted mathematics measured after 6 months or later, r = .49, 95% confidence interval [0.47, 0.52]. After controlling for all moderators in a model, results indicated that (a) different early numeracy including numbering, relations, and arithmetic operations did not differ much in their predictions of different later mathematics; (b) early numeracy as a whole was more predictive of later advanced mathematics skills (word problems) than of later foundational mathematics skills (calculations and fact fluency); (c) early numeracy’s prediction of later mathematics was stronger with longer prediction intervals; and (d) the earlier early numeracy was assessed, the stronger its prediction of later mathematics. Together, these findings suggest that early numeracy may be a unitary construct. Early numeracy does not merely serve as a steppingstone with temporary effects on foundational mathematics; instead, it likely triggers a snowballing effect, cumulatively influencing mathematics development over time. 

ABSTRACT Methane oxidation by aerobic methanotrophs is well known to be strongly regulated by the availability of copper, i.e., the “copper switch.” That is, there are two forms of methane monooxygenase: a cytoplasmic or soluble methane monooxygenase (sMMO) and a membrane-bound or particulate methane monooxygenase (pMMO). sMMO is only expressed and active in the absence of copper, while pMMO requires copper. Previous work has also shown that one gene in the operon of the soluble methane monooxygenase—mmoD—also plays a critical role in the “copper switch,” but its function is still vague. Herein, we show that MmoD is not needed for the expression of genes in the sMMO gene cluster but is critical for the formation of sMMO polypeptides and sMMO activity inMethylosinus trichosporiumOB3b, indicating that MmoD plays a key post-transcriptional role in the maturation of sMMO. Furthermore, data also show that MmoD controls the expression of methanobactin, a copper-binding compound used by some methanotrophs, includingM. trichosporiumOB3b, for copper sequestration. Collectively, these results provide greater insights into the components of the “copper switch” and provide new strategies to manipulate methanotrophic activity. IMPORTANCEAerobic methanotrophs play a critical role in the global carbon cycle, particularly in controlling net emissions of methane to the atmosphere. As methane is a much more potent greenhouse gas than carbon dioxide, there is increasing interest in utilizing these microbes to mitigate future climate change by increasing their ability to consume methane. Any such efforts, however, require a detailed understanding of how to manipulate methanotrophic activity. Herein, we show that methanotrophic activity is strongly controlled by MmoD, i.e., MmoD regulates methanotrophy through the post-transcriptional regulation of the soluble methane monooxygenase and controls the ability of methanotrophs to collect copper. Such data are likely to prove quite useful in future strategies to enhance the use of methanotrophs to not only reduce methane emissions but also remove methane from the atmosphere. 

The rapidly accumulating amounts of waste electrical and electronic equipment (WEEE) is one of the biggest environmental concerns in modern societies, and this problem will be further accelerated in the future. The use of supercritical CO2 (scCO2) mixed with acids has been proposed as a greener solvent system compared to conventional cyanide and aqua regia solvents, however, the mechanisms of scCO2 in metal extraction from WEEE are still poorly understood. Thus, this study focused on the physical, structural, and chemical interactions between scCO2/acid solvents and complex layered components in waste printed circuit boards (WPCBs), one of the common WEEEs. Our study showed that the use of scCO2-based pretreatment allows faster leaching of metals including copper (Cu) in the subsequent hydrometallurgical process using H2SO4 and H2O2, while allowing gold (Au) recovery as hydrometallurgically delaminated solids. This enhancement is due to the selective leaching of Ni and unique inner porous structures created by ScCO2/acid treatment via dissolving the Ca-silicate-bearing fiberglass within the WPCB. Thus, the scCO2-based pretreatment of WPCBs shows a multifaceted green chemistry potential relating to the reduction in solvent usage and targeted recovery of Au prior to shredding or grinding that would reduce any loss or dilution of Au in the subsequent waste stream.