ABSTRACT
Fourteen children (of Arab ethnic origin) with Sotos syndrome are described. They were referred to King Khalid University Hospital, Riyadh between July 1992 and June 1997. Their phenotypic characteristics were compared with established diagnostic criteria. There was a male:female ratio of 1.3:1 and a high rate of consanguinity (36%) among parents. At birth, 54% were large and about one-third showed increased height and occipitofrontal head circumference (OFHC). The neonatal histories revealed respiratory and feeding problems in 21%, followed later by delayed motor milestones and speech development in 57%. During childhood, weight, height and OFHC increased further to > 97th centile in 71%, 71% and 93%, respectively. A seizure disorder affected 43%, and 75% had mental retardation (IQ < 70). A non-specific EEG abnormality was found in half of those with seizures. Cranial CT/MRI showed ventricular dilatation in 15% and one patient had corpus callosum dysgenesis. Abdominal ultrasound revealed hydronephrosis in two patients. Radiological cephalometric measurements showed relative prognathism in cases of Sotos syndrome compared with controls (p = 0.003). The study highlights the importance of considering Sotos syndrome in children who present with psychomotor delay.
Subject(s)
Craniofacial Abnormalities/diagnosis , Gigantism/diagnosis , Adolescent , Cephalometry , Child , Child, Preschool , Cohort Studies , Female , Humans , Infant , Intellectual Disability/diagnosis , Magnetic Resonance Imaging , Male , SyndromeABSTRACT
We demonstrate that the phase conjugation of a beam during nondegenerate four-wave mixing is accompanied by a spatial shift relative to the degenerate conjugate-beam location. Experiments with a photorefractive phase-conjugate mirror reveal that the phase-conjugate beam shifts have a nonmonotonic dependence on the probe's detuning frequency and comprise both lateral displacements of up to 218 mum and angular tilts of up to 34 arc sec. An approximate theory based on spatial dispersion coefficients is in partial agreement with the experimental results.
ABSTRACT
We investigate the transverse and longitudinal modes of a resonator consisting of a spherical mirror, a Gaussian aperture, and a dispersive phase-conjugate mirror (PCM). The photorefractive PCM introduces spatial dispersion in the form of lateral and focal shifts along with temporal dispersion. For both degenerate and nondegenerate operation, the decentered Gaussian beam was found to be a mode whose peak intensity is displaced from the resonator axis. In the nondegenerate case, the components of a mode oscillating at a pair of frequencies that are up and down shifted from the pump frequency by the same amount have different spatial distributions, so that the intensity pattern moves periodically across the output mirror. The resonance frequencies of the longitudinal modes are calculated numerically.
ABSTRACT
A generalization of the Gaussian beam is obtained by introducing a complex-valued shift in the transverse dimension. The resulting beam has a Gaussian intensity distribution with width varying as an ordinary Gaussian beam, but whose peak traces an inclined linear trajectory. The wave fronts are displaced laterally in a sheared fashion. This generalized beam preserves its form after passing through arbitrary paraxial optical components, even if they are decentered. The peak-intensity line is modified by such systems as if it were a ray.
