in the x direction, the water wants to flow in that direction) For a given hydraulic. conductivity, the vertical flow rate depends on the sum of the gravitational potential energy. gradient per unit weight of water (dz/dz =1) and the vertical gradient in soil water pressure.
Origin and spread of the 1278insTATC mutation causing TayâSachs disease in Ashkenazi Jews: Genetic drift as a robust and parsimonious hypothesis. Human Genetics 114 (4): 366â376. pmid 14727180.
Infants with Tay-Sachs disease appear to develop normally for the first few months of life. Then mental and physical abilities decline. The child becomes blind, deaf, and unable to swallow. Muscles begin to waste away and paralysis sets in. Even with the best of care, children with Tay-Sachs disease usually die by age 4. The cause is a gene mutation which is most common in Eastern European Ashkenazi Jews. To get the disease, both parents must have the gene. If they do, there is a 25% chance of the child having the disease.