Yearly Archives: 2006

Stranger than fiction

Sometimes science can be stranger than fiction.

Like this innovative way to settle an age old controversy – that of whether brain cells can form anew after birth it is a well known fact that brain cells once formed are not made again. unlike say for example the skin cells which are shed and then replaced. (Actually we go through a new skin every 1-3 months.)

But research in the early 70’s showed that we actually make new brain cells even after we have grown up. (the technical term is adult neurogenesis).

How is this done? In animals you give them stuff called BRDU which gets in the DNA of the cells. Now a cell only makes new DNA once ie when it is forming. Therefore only those cells take up DNA which are being born. If you look for which cells have taken up BRDU you know these are the cells which have been born after you gave the BRDU to them.

Does adult neurogenesis happen in humans at all? Can’t you give humans BRDU and see? Well no because BRDU is a mutagen. (causes mutations and therefore cancer). What would you do?

Well, here comes the innovation that works around this problem. In the period from 1955-63 there were a lot of nuclear bombs being detonated above ground for “tests”. This lead to the C14 levels in the atmosphere going up. In fact it follows a pattern with the levels coming down exponentially after 1963 when the test ban treaty was signed. This is shown in this graph.

(ignore the line and dot for now)


These ratios of C14 to the normal level would be reflected in the DNA of the cell as well because the C14 is all over the atmosphere which would get into plants and therefore into human food as well. When a cell is born this C14 would go into the nucleus as well. If you could measure C14 levels in the cell DNA you could tell when it is born.

You could do this for all the cells in body and determine the age of each groups of cells – like brain versus intestine. neat.

Next big question – Did it work? Did they show that new neurons are born in the brain after birth? did they? did they?

Well – short answer yes!


The vetical line in the year of birth of the indivudual(~1973). The red dots represent the date of birth of the cells of the different organs. The intestine cells (also have high turnover rates like the skin cells) are the youngest having C14 levels corresponding to being born in ~1995 while the cerebellar cells are the oldest – being born in ~1975.

The clincher here are the cortex cells being clearly born in 1982 or thereabouts, indicating clearly that new neuronal cells can be formed after birth.

Who would ever have thought that nuclear bomb testing would have such a scientifically useful fallout (pardon the pun). And yes truth is stranger than fiction.

For the ones who revel in the details here is the original paper.

(posted originally by samudrika)

Ramujan Prize for Indian mathematician

Just read on the BBC News site that an Indian mathematician, Dr. Sujatha Ramadorai of Tata Instititue of Fundamental Research has been awarded the Ramajuan Prize. She won it for her contributions to the ‘arithemetics of algebraic varieties and for her work on non-commutative Iwasawa theory‘. Congratulations doc!

Nice to see that it’s an Indian that won it, even better when it’s a woman. Women can do math Mr Summers! 😀

What’s not so nice is that TIFR’s website is so pathetic – no mention of Dr. Sujatha’s achievement, and absolutely nothing on her homepage.

This is one reason why post-graduates here know close to nothing about research being done in this country. The only research you hear of, and that can excite you is what’s happening outside. And if you happen to be one who is keen on getting a PhD, (and are sensible), you would head west.

Being in a quite optimistic mood today morning, I hope things will change, and soon.

BTW, if any mathematicians read this post, could you translate Dr. Sujatha’s work in pop-science language??

(originally posted by MadGenius)

Hello World!!

High time I did post here, before more people start doubting my very existence. Had planned initially to blog on something else, but that didn’t happen. That’s a long story, and I will not repeat it here.

As this is going to be an introductory post, I think I shall tell you about what I do. I work in a small bioinformatics based company in my hometown as a research associate. That’s my designation, although I don’t really do any research. What I do is ‘literature curation’ – a field which not many people in biology actually know off. What it involves is basically reading research papers, putting all that data together, and help improve biological databases. Once the data has been collated and meaningfully put together, it can be then used for finding drug targets, designing experiements, etc etc. This ‘collation’ of data can range from simple keyword/abstract indexing of papers to building signalling pathways in specific cell systems.

For more, have a look at these articles from PLoS Computational Biology. Last month’s issue had a very nice editorial on the role of ‘Biocurators’. I especially loved this-

Biocurators can be considered the museum catalogers of the Internet age: they turn inert and unidentifiable objects (now virtual) into a powerful exhibit from which we can all marvel and learn. That would be a decent enough contribution to the world of science, but the task of the biocurator is even more extensive. Computational biologists do not expect to merely walk through the door, cast a casual eye over the exhibit, and exit wiser (although we frequently do); we also want to add our own data to the exhibit, plus pick and choose pieces of it to take home and create new exhibits of our own. Oh, and we would like to do all these things with minimal effort, please. We can be a pretty exacting bunch of customers, and it takes skills over and above a knowledge of biology to juggle the different needs of data submitters, information seekers, and power players.

This wonderful article gives a comprehensive description of a curator’s job while dealing with a (slightly) static database, while this one describes how data can be put together to create a (more dynamic) interaction database.

(originally posted by MadGenius)

On Being a Grad Student

If you’ve been following this blog for a bit you’ve obviously noticed the little strip of the latest PhD comics along the top.

PhD Comics is written and drawn By Jorge Cham, a one time grad student at Stanford University and used to be published in their student newspaper but now appears in a number of newspapers across the US as well as on the web.

One of my favourite series of strips is the Star Wars sequence because it appeals to the geeky side of me too! (Like grad students are not geeky enough!)

Oh, did I mention there was a Matrix series too?

Cartoon Guides

How many times have you got bored reading those textbooks on physics or chemistry? And can anyone really understand statistics besides statisticians? What about history? How many people do you know that read a book on history for fun?

The Cartoon Guide and Cartoon History series are a unique and amazingly creative set of books that attempts to make a number of subjects accessible to everyone. Larry Gonick, the author and cartoonist, spent a number of years in academia (including a year in TIFR, Mumbai!) before he decided that he had a lot more fun drawing cartoons!

Cartoon History of the Universe The Cartoon History series was the first I encountered. I saw a couple of scans of some pages and it immediately gripped my attention. Being in the US at the time, it was easy to find a couple of copies on eBay and quickly ordered issues of the first two volumes. I finished reading them in a couple of days and wanted more! I found the third volume and Cartoon History of the United States at my local library and read those too. They were brilliant, to say the least.

Cartoon Guide to Sex

I next started on the Cartoon Guides. I manged to get my hands on (and read) the Cartoon Guides to Genetics, Statistics, Chemistry, Environment and even Sex! Most of these latter guides were written in collaboration with an expert in the field but nevertheless retauned the fun style that Gonick had already established in Cartoon History. I think what makes these cartoon books work, besides the format of cartooning, is the narrative style of teaching or explaining. A lot of people are more comfortable learning when someone is actively explaining something to them as opposed to read it drily from a book. Gonick’s cartoons maintain this feel by having characters that pepper the book along with the regular illustrations and give that narrative continuity.

When I was a TA at a US university, one of the exercises we did with our students was called a VARK test. VARK – Visual, Audio, Reading and Kinesthetic – referred to ways of learning. The cartoon guides could be said to cover visual (pictures!), reading (there’s text) and kinesthetic (the cartoons point, move, etc) ways of teaching. Maybe that’s why they’re so popular!

Another thing I love is that while each of these books has a bibliography, it isn’t like your standard boring bibliography at the end of other academic books but is also illustrated with cartoons like the rest of the book. Why can’t more textbooks be like this? – My few seconds of fame!

Yesterday my colleague, Prayas came up to me and said that the latest edition of Business Today had an article about and that we were both featured in it.

Obviously, I rushed out and bought a copy of the magazine! 🙂 Unfortunately I can’t link to the story here as the online edition of the magazine is subscription only.

Prayas who had spoken about the need for Creative Commons licenses in India had got a pretty decent write up and a picture of him talking was the image for the story. All that got said about me was:

Ashwan (27), is a science professor from Mumbai who passionately follows science blogs around the globe.

But hey, I’m not complaining! It’s always cool to see your name in print as long as nothing bad is being said about you!

Then this morning, I opened my mailbox to see an email from Peter which had a link to a story by CNN-IBN about!

The short news clip had been uploaded to YouTube by some kind soul and I could finally see my glorious 2 seconds of fame that others had been telling me about for quite a few days!

Here, for your viewing pleasure, is the clip in question. Share and Enjoy!

Go with your GUT

A series of exchanges on a mailing list led me to write a fairly long piece about the theory of relativity, quantum mechanics and grand unified theories (GUTs.) With a little bit of editing, I’ve turned it into my first science blogpost!

Since the time of Newton with his Laws of Motion to present day science, one simple understanding has prevailed. Forces acting upon bodies are what keeps the world going. Literally and figuratively.

While in our everyday life, we can encounter all kinds of forces like the friction when you’re trying to push that heavy table across the floor, to the difficulty you have carrying a heavy package up a flight of stairs, there are only four fundamental forces in nature. All other forces are just manifestations of these four.

Solar System

The one we most commonly encounter and which most people will readily identify is the gravitational force. Gravity is a force that acts between any two bodies that have a mass. It is the force that holds the stars in their places, the solar system together, keeps the moon orbiting the earth, not to mention all the TV satellites that allow us to watch Cartoon Network anywhere in the world (more or less.)

That package I talked about earlier is so hard to carry up a flight of stairs because gravity is pulling down on it and you need to overcome gravity with your legs and arms to get the package up! Just imagine, the entire planet Earth is pulling down at that package and you can beat it with a little effort!

That fact illustrates an important point about gravity. It is the weakest of the four fundamental forces. The strongest of them all is what physicists in a total lack of originality have named the “strong” force (sometimes also referred to as the strong interaction.) This force is what was thought to hold protons and neutrons together inside an atomic nucleus. Today there is a different understanding of that, but more on that later.

The next strongest force is the electromagnetic interaction on which a lot (if not all!) of our modern technology is based on. In fact, practically all the forces we experience in daily life besides gravity are due to electromagnetic interactions!

Electromagnetism is the interaction between charged particles and the electrical and magnetic fields that this creates. If the electromagnetic interaction were stronger than the “strong” force, the protons (which are all positively charged) would fly apart due to repulsion and there would be no possibility of a nucleus forming.

But then, why does the electromagnetic interaction have any effect all? If the “strong” nuclear force is so overwhelming, shouldn’t it wipe out any effect of any other forces? That’s true. And the answer to that is the range at which the forces operate. The “strong” nuclear force is very very strong, but the scale and range it works on is very very small. It falls off to virtually zero beyond a couple of femtometers. (1 million billionth of a meter or 10E-15 meters!)

Today’s understanding of the strong force is that it is a force that affects quarks, the actual fundamental blocks that make up protons and neutrons and the residual effect is seen as a force between protons and neutrons! Lets quit while we can still understand things and move on to the last force in this mixed bag! 🙂

The “weak” force (weak interaction) is another force that manifests itself on the nuclear level. Obviously it gets its name from the fact that it is much much weaker than the “strong” force and weaker than even electromagnetism. Like the “strong” force it also operates on a vanishingly tiny scale (about 10E-18m.) At the risk of being dismissive, most of what the “weak” interaction achieves is of interest only to physicists. About the only physical phenomenon you’re likely to have heard of or encounter (and even then probably only in a physics or chemistry text) is that is due to the “weak” interaction is that of beta decay.

What’s this GUT all about then? and a new start

I attended in Chennai this past weekend and even spoke there on Science Blogging.

Ashwan Lewis on science blogs
Originally uploaded by Jace.

I mostly talked about some of my favourite science blogs and talked about the potential blogging holds for building bridges between scientists and others and even between scientists.

Obviously after the talk I was asked whether I had my own science blog and quite sheepishly I had to say no. But then I thought Why not?

And so here it is. I don’t know whether I’ll be able to maintain the momentum or whether I do know enough about science to be able to write a lot but I sure will try!