DNA STRUCTURE DISCOVERED
February 28, 1953 - Cambridge, MA, U.S.A.
James Watson, from early on this Saturday, spent his time at the Cavendish Laboratory in Cambridge, shuffling cardboard cutout models of the molecules of the DNA bases: adenine (A), guanine (G), cytosine (C) and thymine(T). After a while, in a spark of ingenuity, he discovered their complementary pairing. He realized that A joined with T had a close resemblance to C joined with G, and that each pair could hold together with hydrogen bonds. Such pairs could also neatly fit like rungs meeting at right-angles between two anti-parallel helical sugar-phosphate backbones of DNA wound around a common axis. Such structure was consistent with the known X-ray diffraction pattern evidence. Each separated helix with its half of the pairs could form a template for reproducing the molecule. The secret of life!
BALTIMORE & OHIO RAILROAD
February 28, 1827 - Baltimore & Ohio USA
The Baltimore & Ohio Railroad became the first U.S. railway chartered for the commercial transportation of freight and passengers. Investors hoped that a railroad would allow Baltimore, the second largest U.S. city at that time, to successfully compete with New York for western trade. New Yorkers were profiting from easy access to the Midwest via the Erie Canal.
by John Adams
"...The Revolution was effected before the War commenced. The Revolution was in the minds and hearts of the people; a change in their religious sentiments of their duties and obligations. This radical change in the principles, opinions, sentiments, and affections of the people, was the real American Revolution...."
"...Music is a moral law. It gives a soul to the universe, wings to the mind, flight to the imagination, a charm to sadness and a gaiety and life to everything. It is the essence of order and leads to all that is good, true and beautiful, of which it is the invisible but nevertheless dazzling, passionate and eternal form...."
about Facts about Drugs
Facts about drugs can protect against drug abuse. Legal drugs, such as alcohol and tobacco, kill more people than illegal drugs. Tobacco (smoking cigarettes) kills more people than any other drug. Illegal drugs including heroin, cannabis, ecstasy and amphetamines can have unknown or dangerous ingredients. Mixing drugs, especially with alcohol, can be fatal.
The Earth is the only place
about Earth Day
The Earth is the only place in the entire Universe where we know that life exists. But that won'at be true forever. To us, our Earth seems huge, solid, tailor-made for us, and permanent. But that is just one perspective, born of living on its surface. From a different perspective, none of those things is true. Seen from space, it looks much less unbreakable. Seen from deep space, it shrinks to nothing more than a dot, barely visible in the reflected light of the Sun. From another star, even seeing our planet at all would be a colossal task. We are, after a monumental effort spanning decades, only just now finding other planets orbiting other stars. Are any like Earth? Almost certainly, and in fact there may be billions of planets like ours orbiting alien stars. But while they are like ours, they arena't ours. As with any individual, our world is unique, and precious, and wonderful. Leta's keep it that way.
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Category Information : Home Inspections
This is our Home Inspections category. If you are interested in Home Inspections, feel free to browse these listings. If you have a site that fits within this category, Submit it for inclusion.
Everyone who wants to buy house should hire a certified home inspector. Before hiring, make sure you check the portfolio of the home inspector. Home buyers should always hire home inspector to perform inspection on the house.
Search engine is the term with which we are accustomed with very much. But the web directory is not that same. The web directories are older than search engines according to the time of their invention.