Early development and predictors of morphological awareness: disentangling the impact of decoding skills and phonological awareness

Background: Morphological Awareness (MA) has been demonstrated to be influential on the reading outcomes of children and adults. Yet, little is known regarding MA's early development. Aim: The aim of this study is to better understand MA at different stages of development and its association with Phonological Awareness (PA) and reading. Methods and procedures: In a longitudinal design the development of MA was explored in a group of pre-reading children with a family risk of dyslexia and age-matched controls from kindergarten up to and including grade 2. Outcomes and results: MA deficits were observed in the group with literacy difficulties at all time points. PA was only found to make a significant contribution to MA development at the early stages of formal reading instruction. While first-grade decoding skills were found to contribute significantly to MA in second grade. Conclusions: Evidence supporting a bidirectional relation was found and supports the need for adequate MA intervention and explicit instruction for “at risk” children in the early stages of literacy instruction

Predicting future reading problems based on pre-reading auditory measures: a longitudinal study of children with a familial risk of dyslexia

Purpose: This longitudinal study examines measures of temporal auditory processing in pre-reading children with a family risk of dyslexia. Specifically, it attempts to ascertain whether pre-reading auditory processing, speech perception, and phonological awareness (PA) reliably predict later literacy achievement. Additionally, this study retrospectively examines the presence of pre-reading auditory processing, speech perception, and PA impairments in children later found to be literacy impaired. Method: Forty-four pre-reading children with and without a family risk of dyslexia were assessed at three time points (kindergarten, first, and second grade). Auditory processing measures of rise time (RT) discrimination and frequency modulation (FM) along with speech perception, PA, and various literacy tasks were assessed. Results: Kindergarten RT uniquely contributed to growth in literacy in grades one and two, even after controlling for letter knowledge and PA. Highly significant concurrent and predictive correlations were observed with kindergarten RT significantly predicting first grade PA. Retrospective analysis demonstrated atypical performance in RT and PA at all three time points in children who later developed literacy impairments. Conclusions: Although significant, kindergarten auditory processing contributions to later literacy growth lack the power to be considered as a single-cause predictor; thus results support temporal processing deficits’ contribution within a multiple deficit model of dyslexia

Grapheme-phoneme learning in an unknown orthography: a study in typical reading and dyslexic children

In this study, we examined the learning of new grapheme-phoneme correspondences in individuals with and without dyslexia. Additionally, we investigated the relation between grapheme-phoneme learning and measures of phonological awareness, orthographic knowledge and rapid automatized naming, with a focus on the unique joint variance of grapheme-phoneme learning to word and non-word reading achievement. Training of grapheme-phoneme associations consisted of a 20-min training program in which eight novel letters (Hebrew) needed to be paired with speech sounds taken from the participant's native language (Dutch). Eighty-four third grade students, of whom 20 were diagnosed with dyslexia, participated in the training and testing. Our results indicate a reduced ability of dyslexic readers in applying newly learned grapheme-phoneme correspondences while reading words which consist of these novel letters. However, we did not observe a significant independent contribution of grapheme-phoneme learning to reading outcomes. Alternatively, results from the regression analysis indicate that failure to read may be due to differences in phonological and/or orthographic knowledge but not to differences in the grapheme-phoneme-conversion process itself

Genetic Changes Over Breeding Generations of \u3cem\u3eFestulolium\u3c/em\u3e

Festulolium hybrids are a valuable breeding source for tolerance to abiotic stress and to make grass more persistent under drought and in cold environments. In 2004, the EU Commission enlarged the definition of Festulolium which may now include all hybrids between Lolium sp. and Festuca sp. and not only those between L. multiflorum and F. pratensis. We here report allele frequencies at two unlinked PCR-based marker loci in populations derived from tetraploid (2n=4x=28) L. multiflorum x F. glaucescens hybrids where breeding history enables us to test the effects of selection vs that of genetic drift

Automatic number priming effects in adults with and without mathematical learning disabilities

This study examined automatic number processing in adults with mathematical learning disabilities (MLDs). The performance of adults with MLD during an automatic symbolic and non-symbolic priming task was compared to gender-, age-, and IQ-matched controls. No difference in the priming distance effect was found between the adults with and without MLD, suggesting that adults with MLD have an intact magnitude representation. Moreover, the adults with MLD did not have problems in processing the numerical symbols 1-9, suggesting that this basic deficit which is experienced by children with MLD is resolved by adulthood

Aroma in rice : genetic analysis of a quantitative trait

Une nouvelle approche a permis de cartographier pour la première fois un gène majeur et 2 QTL contrôlant l'arôme du grain chez le riz. Elle impliquait la combinaison de deux techniques, la quantification des composés volatils des eaux de cuisson par CPG et la cartographie par marqueurs moléculaires. Quatre types de marqueurs moléculaires ont été utilisés (RFLP, RAPD, STS, isozymes). L'évaluation et la cartographie ont été faites sur une population d'haploïdes doublés qui conférait une évaluation précise du caractère en permettant l'analyse de grandes quantités de grains par génotype et a rendu possible la comparaison de la CPG et des tests sensitifs. La taille de population (135 lignées) fournissait une bonne précision de cartographie. Plusieurs marqueurs du chromosome 8 ont été trouvés liés à un gène majeur contrôlant la présence de 2-acétyl-1-pyrroline (AcPy), le composé principal de l'arôme du riz. De plus, nos résultats ont montré que la concentration en AcPy dans les plantes est régulée par au moins deux régions chromosomiques. Les estimations de fréquences de recombinaison du chromosome 8 ont été corrigées pour les fortes distorsions de ségrégation. Cette étude confirme que l'AcPy est le composé principal de l'arôme du riz. L'utilisation des marqueurs liés au gène majeur et aux QTL de l'AcPy en sélection assistée par marqueurs (en backcross) peut être envisagée. (Résumé d'auteur