Mathematics and reading difficulty subtypes: minor phonological influences on mathematics for 5-7-years-old.

Linguistic influences in mathematics have previously been explored through subtyping methodology and by taking advantage of the componential nature of mathematics and variations in language requirements that exist across tasks. The present longitudinal investigation aimed to examine the language requirements of mathematical tasks in young children aged 5-7 years. Initially, 256 children were screened for mathematics and reading difficulties (RDs) using standardized measures. Those scoring at or below the 35th percentile on either dimension were classified as having difficulty. From this screening, 115 children were allocated to each of the mathematical difficulty (MD; n = 26), MDRD (n = 32), RD (n = 22) and typically achieving (n = 35) subtypes. These children were tested at four time points, separated by 6 monthly intervals, on a battery of seven mathematical tasks. Growth curve analysis indicated that, in contrast to previous research on older children, young children with MD and MDRD had very similar patterns of development on all mathematical tasks. Overall, the subtype comparisons suggested that language played only a minor mediating role in most tasks, and this was secondary in importance to non-verbal skills. Correlational evidence suggested that children from the different subtypes could have been using different mixes of verbal and non-verbal strategies to solve the mathematical problems.

Cloning, mapping, and retinal expression of the canine ciliary neurotrophic factor receptor alpha (CNTFRalpha).

PURPOSE: To clone, map, and determine the site of expression (mRNA and protein) of the alpha subunit of the receptor for ciliary neurotrophic factor (CNTFRalpha) in the normal adult canine retina. METHODS: The complete coding sequence of the canine CNTFRalpha cDNA was cloned, and radiation hybrid (RH) mapping was used to determine the chromosomal localization of the gene. CNTFRalpha mRNA expression in retina and other tissues was examined by reverse transcription-polymerase chain reaction. The cellular distribution of CNTFRalpha in the canine retina was studied by in situ hybridization and immunocytochemistry. RESULTS: Canine CNTFRalpha shares a high degree of homology with the human, mouse, and rat coding sequences, both at the nucleotide and amino acid level, but has lower homology with the chicken. CNTFRalpha was RH mapped to CFA 11 (Canis familiaris autosome 11) in the dog, a region showing homology to the short arm of human chromosome 9 (9p13). The gene is transcribed in retina, brain, spleen, lung, liver, and kidney. In the retina, CNTFRalpha was highly expressed by photoreceptors, but both the transcript and protein were also found in the RPE, inner nuclear layer, and ganglion cells. CONCLUSIONS: These findings demonstrate that CNTFRalpha is expressed by rods and cones in the normal adult canine retina and suggest that ciliary neurotrophic factor (CNTF) could have a direct photoreceptor rescue effect by binding to CNTFRalpha in these cells. This could open novel pathways for the treatment of retinal degeneration in animal models and humans.