Mouhatti Saga

Dyscalculia is a specific difficulty in learning mathematics that strongly influences activities of daily living that require skills such as counting and simple mathematical operations. The aim of this study is to investigate the effect of negative emotions on mathematical performance in children with and without developmental dyscalculia using psychosocial tests, a quality of life test, an anxiety test and the Zareki-R mathematical performance test. This pilot study was realized on a sample of 20 children in the first year of secondary school (a group of 10 dyscalculic children and another group of 10 control children with an average age of 12.65 years). Descriptive statistics showed that dyscalculic children had low scores on all Zareki-R subtests. The Mann Whitney analysis revealed a significant difference between dyscalculic children and typically developing children on the Zareki-R subtests and the quality of life test, but no significance was found for the anxiety test. Analysis of the ANOVA by gender revealed no significant differences for the three tests, and the opposite for the ANOVA by age (F = 3.86, dll = 2, p ˂ 0.05). Using multiple linear regression, the subtests of physical quality of life, emotional quality of life and academic quality of life were significantly different for the two groups. In conclusion, the psychosocial quality of life and the high level of anxiety in dyscalculic children strongly influence their performance in mathematics.

Ralstonia solanacearum is one of the most destructive pathogens of vegetables causing very important economic losses. In 2019, 20 strains of R. solanacearum were collected from potato tubers in Morocco. After their identification, the inhibitory effect of colloidal solutions of chitin and/or chitosan was evaluated in vitro on a solid medium (Mueller Hinton) supplemented with these biopolymers. The concentrations (25, 50, or 100 mg L-1) contributed to significant inhibition of the growth of the isolated strains that led to an inhibition of 45.04% with the combination of chitin-chitosan (100 mg L-1), 58.92% with the addition of 100 mg L-1 of chitin, and 68.74% in the presence of chitosan at 25 mg L-1. Likewise, in experiments with Solanum lycopersicum L. seedlings, chitin derivatives significantly promoted stem and root growth. Stem length increased by 54.95% when chitin was added at 25 mg L-1, while soil amendment with 100 mg L-1 of chitosan increased root length by 82.55% compared to the control. The severity of bacterial wilt due to R. solanacearum was reduced by 117.02% when we added 100 mg L-1 of chitosan to the soil. However, the severity of this disease decreased by 142.86% when the soil was amended with chitin at 50 mg L-1. These findings are consistent with prior research that suggests using this technique to manage bacterial wilt caused by R. solanacearum.

The study of dyscalculia requires an analysis of the current developed hypotheses which describe the cognitive mechanisms involved in this neurodevelopmental disorder. The objective of our review is to determine any progress in modeling developmental dyscalculia. The first hypothesis suggests that dyscalculia is the consequence of a specific deficit level number on the precise number system and the approximate system. Then, the second hypothesis states that developmental dyscalculia is linked to a failure to process non-symbolic representations of numbers. On the other hand, the third suggests that dyscalculia is caused by a lack of access to numerical quantities from symbols. However, the last hypothesis asserts that developmental dyscalculia is linked to general deficits. All these hypotheses are compatible with recent neuroimaging results and raise new horizons for experimentation, which will allow the development of precise diagnostic tools and the improvement of intervention strategies and the remediation of developmental dyscalculia.