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.
But a baby with Tay-Sachs disease is born without one of those important enzymes, hexosaminidase A (HEXA). So, as those fatty proteins build up in the brain, they hurt the baby's sight, hearing, movement, and mental development. A child can only get Tay-Sachs by inheriting the gene for it from both parents. Tay-Sachs can be detected before birth, so couples who are thinking of having children may want to get a blood test to find out whether their child would be likely to have it. Who Is at Risk for Tay-Sachs? Each year, about 16 cases of Tay-Sachs are diagnosed in the United States.