RESUMO
El síndrome de banda amniótica (SBA) o complejo de disrupción de banda amniótica es aquella malformación congénita que ocurre como consecuencia de bridas amnióticas de etiología heterogénea, patogénesis que involucra una serie de manifestaciones clínicas fetales, tales como constricción, amputación y múltiples defectos craneofaciales, viscerales y de la pared del cuerpo. La prevalencia estimada de SBA oscila entre 1:15,000 y 1:1,200 nacidos vivos. Afecta a ambos sexos por igual. El diagnóstico prenatal puede sospecharse tan pronto como el primer trimestre tardío, cuando las imágenes por ultrasonido detectan anillos de constricción, amputaciones de extremidades y/o defectos craneofaciales. La terapia prenatal puede ofrecer una alternativa de tratamiento con la liberación de anillos de constricción bajo fetoscopia en aquellos fetos que se verían beneficiados con el procedimiento.
Amniotic band syndrome (ABS) or amniotic band disruption complex is a congenital malformation that occurs because of amniotic flanges of heterogeneous etiology, a pathogenesis that involves a series of fetal clinical manifestations, such as constriction, amputation, and multiple craniofacial, visceral and wall defects. The estimated prevalence of ABS ranges from 1:15.000 to 1:1.200 liveborn. It affects both sexes equally. Prenatal diagnosis may be suspected as early as the late first trimester when ultrasound imaging detects constriction rings, limb amputations and/or craniofacial defects. Prenatal therapy may offer an alternative treatment with release of constriction rings through fetoscopy in those fetuses that would benefit from the procedure.
RESUMO
Habituation is a form of nonassociative learning observed in a variety of species of animals. Arguably, it is the simplest form of learning. Nonetheless, the ability to habituate to certain stimuli implies plastic neural systems and adaptive behaviors. This paper describes how computational models of habituation can be applied to real robots. In particular, we discuss the problem of the oscillatory movements observed when a Khepera robot navigates through narrow hallways using a biologically inspired neurocontroller. Results show that habituation to the proximity of the walls can lead to smoother navigation. Habituation to sensory stimulation to the sides of the robot does not interfere with the robot's ability to turn at dead ends and to avoid obstacles outside the hallway. This paper shows that simple biological mechanisms of learning can be adapted to achieve better performance in real mobile robots.