ABSTRACT
In the current study, the development in reading comprehension performance of students in lower-SES versus higher-SES schools during and after school closures due to Covid-19 lockdowns was examined, and compared to a normed reference group. Furthermore, we explored protective factors against negative effects at the time of school closures, by pinpointing successful practices in a sub sample of resilient lower-SES schools. The total sample consisted of 2202 students followed from grade 2-4. Overall, we found that students in lower-SES schools made less progress over time than students in higher-SES schools. On average, students made less progress during the lockdowns, but here, the interaction with SES was not significant. Students' reading comprehension levels partially recovered after the lockdowns. Questionnaire-data revealed that schools were better prepared during the second lockdown, with teachers making more use of digital means, and providing more online reading instruction. In addition, collaboration with the parents seemed to have improved. The in depth interviews with resilient lower-SES schools revealed that the introduction of online education and investing in educational partnerships with parents may have helped to minimize the negative impact of lockdowns. We conclude that lockdowns have a negative effect on the development of reading education, but that students are resilient. Digital means and partnership with parents may be seen as protective factors to attenuate the negative effects of emergency remote teaching.
ABSTRACT
In recent years, the externalization of electrons as part of respiratory metabolic processes has been discovered in many different bacteria and some archaea. Microbial extracellular electron transfer (EET) plays an important role in many anoxic natural or engineered ecosystems. In this study, an anaerobic methane-converting microbial community was investigated with regard to its potential to perform EET. At this point, it is not well-known if or how EET confers a competitive advantage to certain species in methane-converting communities. EET was investigated in a two-chamber electrochemical system, sparged with methane and with an applied potential of +400 mV versus standard hydrogen electrode. A biofilm developed on the working electrode and stable low-density current was produced, confirming that EET indeed did occur. The appearance and presence of redox centers at -140 to -160 mV and at -230 mV in the biofilm was confirmed by cyclic voltammetry scans. Metagenomic analysis and fluorescence in situ hybridization of the biofilm showed that the anaerobic methanotroph 'Candidatus Methanoperedens BLZ2' was a significant member of the biofilm community, but its relative abundance did not increase compared to the inoculum. On the contrary, the relative abundance of other members of the microbial community significantly increased (up to 720-fold, 7.2% of mapped reads), placing these microorganisms among the dominant species in the bioanode community. This group included Zoogloea sp., Dechloromonas sp., two members of the Bacteroidetes phylum, and the spirochete Leptonema sp. Genes encoding proteins putatively involved in EET were identified in Zoogloea sp., Dechloromonas sp. and one member of the Bacteroidetes phylum. We suggest that instead of methane, alternative carbon sources such as acetate were the substrate for EET. Hence, EET in a methane-driven chemolithoautotrophic microbial community seems a complex process in which interactions within the microbial community are driving extracellular electron transfer to the electrode.
