Reduced Folic Acid Intake and Absence of MTHFR Polymorphism in Egyptian Mothers of Children with Down Syndrome

A video signal transmission method and apparatus for instantaneously providing a normally reproduced picture upon start of an image data transmission or in other potentially unstable states through steady processing, wherein the image signal of one frame is first divided into a plurality of blocks. The image signal of the divided blocks is coded by intraframe coding and interframe coding. The intraframe-coded signal for one frame is transmitted periodically. Meanwhile, the magnitude of the correlation between two blocks is detected, one of the two blocks belonging to a given frame and corresponding to the other block belonging to the preceding frame. Then the quantization characteristic of the image signal to be transmitted is controlled in accordance with the detected magnitude of the correlation.