Four interesting finds

I usually don't write reviews of other sites on Math Pages, or recommend anything. But from time to time I stumble on sites or articles, that I think would be of interest to my readers. I usually just bookmark them to write about in the future, when I will have time and enough links to write about. I already have four such bookmarks, so it is time to share.

1. I recently found out that the Clay Mathematics Institute made a lot of books and lecture notes available on the net in .pdf format. You can get them at the official site.

2. There is an interesting new site for those who write research pages. It is called 1researcher. It is currently in beta version. A little quote from the site: "Explore the power of management tools designed expressly for Researchers. Swiftly create Research Notes and Biosketches (or Resumes), promote your Papers with a Research Blog, and setup a private Archive of Papers you can access from anywhere over the net - all as an extension of the work you already do. "

3. Fractal Science kit - "The Fractal Science Kit provides a rich framework for exploring the world of fractals. It handles the common processing steps required to generate a fractal image so that you can concentrate on the fun part; developing the equations, transformations, and coloring schemes that define the fractal."

4. The life of the photon - It is hard to say what exactly this is, a science fiction or a short story from a lecture somewhere, but it was interesting to read. A small example: "The photon enters the Earth's atmosphere and it's path is bent alarmingly. This is not due to gravity, but refraction as the lens of our air slants its path before its final plummet to the nighttime country-side below. It penetrates the earth's envelope of gas in one one-thousandth of a second. Many of its co-travelers which have so far survived the journey end their existence hitting the ground, tree branches, and even the jacket of a lone telescopic observer. However our photon along with a handful of others falls right down the barrel of a waiting telescope."

Update: Somehow I managed to forget a fifth link... Well, just pretend that the title says "five" instead of "four"...:

5. The Decline of the Library and Museum of Alexandria - An interesting article about the most famous library in the world.