Genomic Basis of Convergent Island Phenotypes in Boa Constrictors.

Convergent evolution is often documented in organisms inhabiting isolated environments with distinct ecological conditions and similar selective regimes. Several Central America islands harbor dwarf Boa populations that are characterized by distinct differences in growth, mass, and craniofacial morphology, which are linked to the shared arboreal and feast-famine ecology of these island populations. Using high-density RADseq data, we inferred three dwarf island populations with independent origins and demonstrate that selection, along with genetic drift, has produced both divergent and convergent molecular evolution across island populations.

Gestalt laws of perceptual organization in an embedded figures task: evidence for hemispheric specialization.

An embedded figures task was used to investigate hemispheric specialization for visual parsing. Error data from 40 normal right-handed males revealed a right-hemisphere advantage for parsing governed by the Gestalt laws of organization. In contrast, for parsing that violated those laws, subjects who could perform such parsing at better-than-chance levels showed a left-hemisphere advantage.

Hemispheric differences in global versus local processing of hierarchical visual stimuli by normal subjects: new data and a meta-analysis of previous studies.

Twenty-four normal right-handed male subjects classified hierarchical visual stimuli (small letters arranged to form larger letters), which were presented separately to each cerebral hemisphere. Previous studies using similar paradigms have yielded mixed evidence for the specialization of local, analytic processing in the left hemisphere and global, holistic processing in the right hemisphere. No statistically significant evidence for such a pattern of specialization was evident in the results of the present study.

Ataxia and deafness in children due to bacterial meningitis.

Eight children with postmeningitis ataxia had detailed neurologic, audiologic, and neurovestibular evaluations. Prolonged fever, prolonged hyponatremia, or septic arthritis occurred in six during hospitalization. Severe to profound sensorineural hearing losses were present in seven of the children.