Interstitial deletion of long arm of chromosome 13

The case is presented of a patient with the karyotype 46,XX,del(13q)(pter----q22::q32----qter) confirmed by densitometry and a phenotype of mental and growth deficiency, hypotonia, hypertelorism, ptosis, broad nasal bridge, protruding upper incisors, short neck, dislocation of the hip, hypoplasia of the thumbs, fusion of fourth and fifth metacarpal bones and syndactyly of toes. The findings are compared with those of well documented cases with a similar deleted segment of the long arm of chromosome 13. Although it seems obvious that a clinical syndrome for the distal deletion 13q appears to exist more studies with banded chromosomes are needed.     

Asymptotic behaviour of a model of hierarchically structured population dynamics

 A hierarchically structured population model with a dependence of the vital rates on a function of the population density (environment) is considered. The existence, uniqueness and the asymptotic behaviour of the solutions is obtained transforming the original non-local PDE of the model into a local one. Under natural conditions, the global asymptotical stability of a nontrivial equilibrium is proved. Finally, if the environment is a function of the biomass distribution, the existence of a positive total biomass equilibrium without a nontrivial population equilibrium is shown. Received 16 February 1996; received in revised form 16 September 1996