Phase space of double pendulum

The chaotic behaviour of double pendulum is very interesting. If we slightly change the initial angle, we will end up in completely different phase space. I decided to see how its changing, so I put the tow initial angles in nested loop and incremented in steps of 5 degree, from 0 to 90 degree.
The result is the colourful display of phase space. As you see in the video, the one in the top left is the time graph and bottom right is the phase space. It's a python script with gnuplot.

Easy reference management using CiteULike,BibTex and Latex

I have seen many grad students having difficulties is reference management. They go for expensive software like EndNote, still having difficulties in integrating with their text editors.

For Linux users this is not a big problem, they have everything in their hand. I am just giving here one combination of tools which is useful for reference management. I maintain my reference library in CiteULike. You can have a posting button in web browser. When you see an article, you can just click that button, then that article is added to your library. You can optionally give a key, which could be used as a reference key in Bibtex. Once you have done, you can export complete library to bibtex(.bib) format. Then you can add this .bib file in your latex file
\bibliographystyle{alpha} (style for references)
\bibliography{bibtex file} (without .bib extension)

where ever you want to cite an article from your bib file, you can just give \cite{key} where key is the bibtex reference key.
The compiling is bit different, you have to compile several time to get the correct output.

1. pdflatex input-file : complains about undefined citations
2. bibtex input-file : generates a bbl-file
3. pdflatex input-file : complains about undefined citations
4. pdflatex input-file

You will have to repeat the procedure every time you add or remove citations, as they will imply changes in the bbl-file.

We can easily change the style, just by changing one word. This gives the greate flexibility and advantage.

A Cro-Magnon

After a long time I really enjoyed watching one of the best science fiction monies. Usually science fiction movie has certain characteristics like some characters or weapons you have never seen before, space ships, time machines etc..etc.. and everything filled with modern day graphics. Is it possible to make a science fiction movie without those characteristics?. YES.. "The man from earth" is a perfect example. The entire story took place inside a house, but your mind will travel from upper Palaeolithic time to the present day.

There are many reviews about the movie, so I don't want to write one. But I would like to emphasise one psychological aspect of the movie. The protagonist of this movie is telling an "unbelievable" truth in a group of five experts(Professors) , but he is leaving the credibility to the choice of the listeners. He never stress others to believe him. This is a cleaver way to create strong doubt in the listeners mind and steer them in a direction he wants. He answers every question consistently and also sliped at some points, but covering with an argument like "touch of senility". The discussion among the professors were really interesting. What every doubts you have in your mind will be asked by one of them and answered by the protagonist. Screenplay was so good that you will get the feeling that you were also part of that discussion.

I would compare this with matrix, because both are conceptually very good.