Twins Info

Twins are normally either identical—the result of a single sperm fertilizing a single egg, which then splits and duplicates itself—or fraternal, developing from two separate eggs fertilized by two separate sperm. But last March, doctors reported the first known case of semi-identical twins. They did some detailed genetic analysis, we discovered that there was a single maternal contribution to the twins but they had a mixture of two paternal contributions. It suggests that there were two sperm involved but maybe only one egg. With these twins, whose identities were not revealed, each paternal contribution contained a different sex chromosome. This resulted in the conception of a boy with normal genitalia and a girl who was developing both ovarian and testicular tissue. It was the sexually ambiguous genitalia that brought her to doctors’ attention. After several years of studying genetic material from the twins and their parents, the team came up with two possible scenarios.

Fastest Bullet Train Info

Clearly not ready to let go of the Olympic motto — higher, faster, stronger — even after the end of the 2008 Games, Chinese state media has announced the country’s plans for developing the world’s fastest bullet train. The new train would link China’s political capital Beijing to its commercial centre Shanghai and would run at a speed of 380 km per hour, or 30 km per hour more than the current generation of bullet train, making it the fastest the world has ever seen. The proposed project connects the two cities of Shangai and Beijing traversing a distance of 1318 km. The running hours between the two cities will be cut down to four hours from ten hours. Works have started from April 2008 and is continued at rapid pace. When completed it would be a transportation marvel, enabling upto 380 km per hour.

Sixth-Grade Experience

A little boy I was taking care of was in the sixth grade, and he wanted to know about a particular mathematical problem. It was a relatively simple problem, but I didn’t remember how to do it. I looked through his book to remember how it went so I could explain it. As I was going through his book, I saw the geometry I needed—in a sixth-grade math book! The author of the book didn’t understand what I was seeing, because he was thinking along a totally different line. But I saw in the mathematics of it something I’d been looking for, and it was the key that tied these two primary sequences together.