Mutation or deletion of the PAX6 gene underlies many cases of aniridia. Three lines of evidence now converge to implicate PAX6 more widely in anterior segment malformations including Peters' anomaly. First, a child with Peters' anomaly is deleted for one copy of PAX6. Second, affected members of a family with dominantly inherited anterior segment malformations, including Peters' anomaly are heterozygous for an R26G mutation in the PAX6 paired box. Third, a proportion of Sey/+ Smalleye mice, heterozygous for a nonsense mutation in murine Pax-6, have an ocular phenotype resembling Peters' anomaly. We therefore propose that a variety of anterior segment anomalies may be associated with PAX6 mutations.

No abstract

Conversational interaction studies have typically focused either on second language (L2) learners participating in native speaker-nonnative speaker (NS-NNS) dyads or in NNS-NNS dyads. This study analyzes the task-based interactions of 26 naturally occurring learner dyads in an intermediate-level, university Spanish language classroom, 13 of which were matched L2 learner dyads and 13 of which were mixed L2 learner-heritage learner (HL) dyads. Specifically, the study compared the two dyad types to determine whether they differed in their focus on form or in the amount of talk produced during interaction. Results revealed that the two types of dyads were largely similar, although instances of focus on form were more likely to be resolved in a target-like way by mixed L2-HL pairs than by matched L2-L2 pairs, and there was significantly more target language talk in mixed pairs. Interestingly, L2 learners used the target language significantly more with HL learners than they did with other L2 learners, suggesting that different conversational norms may be at play in the two pair types. Furthermore, posttask questionnaire data indicated that L2 and HL learners alike saw the interaction as a greater opportunity for the L2 learner's development than for the HL learner's, calling into question whether classroom contexts like this one meet the needs of HL learners.

This study is a replication and extension of Swain and Lapkin's (in press) study of the developmental effects of learners noticing differences between their own and native speaker output. In their study, task repetition, noticing and participation in stimulated recalls were all factors that might have contributed to more targetlike usage in subsequent output. The current study separated the effects of each of these factors. Fifty-six L2 Spanish learners were randomly assigned to three groups: (1) Task repetition (participants repeated the tasks without additional treatment); (2) Noticing (participants repeated the task and compared their original output to NS reformulation); and (3) Noticing + SR (same as Noticing group with the addition of a stimulated recall session). Reformulations were traced throughout the learners’ output. Analysis of the data indicates that learners noticed differences between their own essays and the reformulated writing, and that there were quantitative differences in the output of participants from different treatment groups, with learners who participated in both noticing and stimulated recall incorporating significantly more targetlike forms in the post-treatment output than learners from the other groups.

This study examines the relationship between learners' production of modified output and their working memory (WM) capacity. The task-based interactions of 42 collegelevel, native English-speaking learners of Spanish as a foreign language were examined. A relationship was found between learners' WM test scores and their tendency to modify output. Specifically, greater processing capacity was related to greater production of modified output during interaction.Keywords second language acquisition (SLA); modified output; working memory capacity; interaction; task-based research; corrective feedback Participation in conversational interaction has been argued to facilitate second language (L2) learning in a number of ways Mackey et al. Modified Output and Working Memory Capacitywork, carried out with both children and adults in classroom and laboratory settings, has demonstrated the benefits not only of interaction as a whole but also of a variety of specific interactional processes (Braidi, 2002;de la Fuente,