The association between socioeconomic disadvantage and children’s working memory abilities: A systematic review and meta-analysis

Background and objective Working memory is an essential cognitive skill for storing and processing limited amounts of information over short time periods. Researchers disagree about the extent to which socioeconomic position affects children’s working memory, yet no study has systematically synthesised the literature regarding this topic. The current review therefore aimed to investigate the relationship between socioeconomic position and working memory in children, regarding both the magnitude and the variability of the association. Methods The review protocol was registered on PROSPERO and the PRISMA checklist was followed. Embase, Psycinfo and MEDLINE were comprehensively searched via Ovid from database inception until 3rd June 2021. Studies were screened by two reviewers at all stages. Studies were eligible if they included typically developing children aged 0–18 years old, with a quantitative association reported between any indicator of socioeconomic position and children’s working memory task performance. Studies were synthesised using two data-synthesis methods: random effects meta-analyses and a Harvest plot. Key findings The systematic review included 64 eligible studies with 37,737 individual children (aged 2 months to 18 years). Meta-analyses of 36 of these studies indicated that socioeconomic disadvantage was associated with significantly lower scores working memory measures; a finding that held across different working memory tasks, including those that predominantly tap into storage (d = 0.45; 95% CI 0.27 to 0.62) as well as those that require processing of information (d = 0.52; 0.31 to 0.72). A Harvest plot of 28 studies ineligible for meta-analyses further confirmed these findings. Finally, meta-regression analyses revealed that the association between socioeconomic position and working memory was not moderated by task modality, risk of bias, socioeconomic indicator, mean age in years, or the type of effect size. Conclusion This is the first systematic review to investigate the association between socioeconomic position and working memory in children. Socioeconomic disadvantage was associated with lower working memory ability in children, and that this association was similar across different working memory tasks. Given the strong association between working memory, learning, and academic attainment, there is a clear need to share these findings with practitioners working with children, and investigate ways to support children with difficulties in working memory.

Influence of some bio-products on the biological and productive characteristics of bird’s foot trefoil grown for forage

During the 2010-2012 period the influence of some bioproducts being mainly a combination of macro and micronutrients at different concentrations on the productivity, botanical and morphological composition of bird?s foot trefoil swards was studied. The experiment was carried out on the experimental field of the IMSA - Troyan by the completely randomized method with 4 replications and harvest plot size of 5 m2. Four bio-products phosphorus humate in dose of 3000 l/ha, boron humate (1600 l/ha) and molybdenum humate (1600 l/ha) and their combination phosphorus humate (2500 l/ha) + boron humate (1000 l/ha) + molybdenum humate (1000 l/ha) were studied. They were applied at the 2-4 leaf. The results showed that solely phosphorus humate had a positive influence, which increased the dry matter yield only by 8.7% and the results were not statistically significant.. It was found that the data had a unidirectional character with regard to the leafiness degree during the years as a result of the applied bio-fertilizers. Their application had a positive effect on the leafiness. The phosphorus humate showed a tendency to increase the relative portion of stems in the sward from the first to the third year. The kind of the applied bio-fertilizers was not of substantial importance to the degree of stem growth and botanical composition of the sward.

Effect of whole-tree and conventional forest harvest on soil microarthropods

The effect of whole-tree and conventional harvest on soil microarthropods, Collembola and Acari, was investigated in a mixed conifer–hardwood forest on the Canadian Shield. Harvesting had a major effect on their populations which declined to 56 and 68% of those on the uncut plot for the whole-tree and conventional harvest plots, respectively. Species composition was unaffected by harvesting although there were shifts in dominance. Total numbers of microarthropods and numbers of Oribatei, Prostigmata, and Mesostigmata found on the uncut plot were significantly greater (P < 0.05) than on harvested plots. Slightly higher (P > 0.05) numbers of Collembola were recorded from the conventional harvest plot than the uncut plot. Oribatei, Prostigmata, and Collembola were more abundant (P < 0.01) on the conventional harvest plot than the whole-tree harvest plot. Of the two forest harvesting methods, conventional harvest had a lesser impact on soil microarthropods. Because the forest soil fauna is intimately involved in decomposition, nutrient cycling, and soil formation, our findings suggest that long-term site productivity will be greater following conventional harvest than whole-tree harvest.