So, there are at least three hundred different types of neurons with one type of odorant receptor each in the epithelium.
Each odorant receptor can bind not one, but many specific different odorants, but with different affinities. So, lets say the rose odorant molecule is bound by a set of ten different odorant receptors. But even these ten bind it with different affinities. So this creates a fine tuning that enables difference between many many times more than odorants that can easily be detected. What happens next is the key. These odorant receptors in these neurons bind an odorant. The neurons are long cells, going deep in to a brain region called the olfactory bulb. They end here in structures called glomeruli.
Each type of neuron with one odorant receptor ends in a specific glomeruli. But what happens when the odorant binds? How is the message actually transmitted? When the odorant molecule binds that odorant receptor in the neuron, it triggers a few adjacent proteins, which go on to cause the synthesis and release of small molecules, called second messengers.
These number in the thousands for every single odorant molecule that binds. So, there is a natural amplification. These molecules travel down the neuronal cell, and cause it to release a neurotransmitter seen those ads on TV, for anti-depressant drugs, where a cartoon of one molecule releasing a thousand molecules happens?
That stuff is real. These released neurotransmitters can now go across and bind their own specific receptor proteins, which will trigger an influx or efflux of positive or negatively charged ions sodium, potassium, chlorine, calcium , through ion channels. This results in a chain of reactions, with specific proteins being made, activated, removed or inhibited.
The brain then forms a specific memory for an odorant, registers it, and subsequently remembers it for future reference. Not in the olfactory system though. Normal neurons suffer constant abuse some nasal inhalers are especially nasty in killing olfactory neurons , but many are replaced. Replaced, 24 hours a day, seven days a week, until we die. But the battle is a struggle, and replacement often cannot keep up with destruction, so we suffer losses in our sense of smell. Postscript: I purposely avoided the just as fascinating processes that pheromones participate it.
Monday, January 16, A quick buck, and learning more. A quick buck? This little story came back to me last evening. It happened some 14 years ago. Dusshera time, and I was spending my holidays with my aunt and uncle in Calcutta. Lots of pujo festivities all around, a great atmosphere in a great and friendly city, and a good bit of rain. I used to walk around in the evenings, to explore the surroundings.
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This was along a little road a couple of kilometers from New Alipur where my aunt and uncle lived. This road gently sloped down, to reach a small trough, and then gently went uphill again. The road like many roads then in Calcutta was in a typical state of semi-repair. It was motorable, but only in second or third gear. There were some very large stones covering the potholes there.
One afternoon it rained like it can only rain in Calcutta. A torrent of water filled the streets, and like always, the streets remained flooded. Feeling adventurous, I went out after the rains stopped, and walked by that street. And there was quite a spectacle happening there. Cars would cautiously descend the street, to reach the trough, by which time the water would be well over knee high. Before the cars could ascend the trough and go up the street again, they would become waterlogged and stall. This was a source of much merriment for all.
But there were a group of intrepid youth, who looked like college students or who should have been in college , four in all, who were there ready for rescue. They would stand by the side, watch a car sputter and stall, and then rush in to rescue the hapless driver, extricating the car. Typically, the driver would hand out a few currency notes in gratitude, which these guys would happily accept. And all would be well again. I took the same walk the next day, after the water had receded, and walked by the trough. I noticed that the large stones in the potholes had vanished. It could be that they had been washed away by the rains.
But the stones were so large and heavy that it seemed highly improbable. It could also be that the youth were helping out purely from altruistic reasons like most Calcuttans would. Or it could be that the youth who were probably local had planned it all and removed the stones.
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Then they could rescue the hapless drivers and at the end of the day have a sizeable income. Anyway, as I look back, there definitely was a good bit of entrepreneurial energy in those youth. The same entrepreneurial energy you see all around in every corner in India. Champa Mahila Society CMS is this wonderful organization which amongst other things has a bunch of schools in the sundarban region in Bengal.
The local government school there is in rather terrible shape in terms of the education imparted. CMS started a program for dropout girls in the area. The girls are provided with food, clothing, education, vocational training and they also enjoy games and cultural activities. The girls in this school absolutely love it there, and so do their parents. The school started off for 30 girls, and now there are close to , and the parents want the poor, exhausted, stretched CMS folks to start more of these schools.
The purpose of these schools, as mentioned earlier, is for dropout girls to get back in to school readiness, and then go and join the government school. Here they have a great learning environment, and learn a ton of stuff. Ask them as my friend Swati did, on her visits there and they grin sheepishly and say that the girls are not going to learn any thing in the government school, so they might as well be here and learn something.
Six year old dropouts indeed. Labels: culture and society. Friday, January 13, Happy hour: Nobels that could have been. There have been some remarkably productive scientists who, in the course of their careers managed to come up with not just one but many path breaking findings, each of which could have won a Nobel prize.
Yet very few of them actually won more than one Nobel prize in science. Bardeen won two Physics prizes, while Fred Sanger won two chemistry prizes, the first in the fifties for work on the structure of insulin, and the next in , for his work on DNA sequencing. Linus Pauling won two, one for Chemistry and another for peace! Here are some people who did win a Nobel, but only once.
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They perhaps should have won another for some other equally if not more epoch work. Albert Einstien, the obvious name on the list, for the theory of relativity. They gave him a Nobel for discovering the photoelectric effect, another seminal but perhaps less impressive discovery. Linus Pauling yes, he could have had three Nobels! Or yet another one a fourth , for discovering alpha helices any one studying protein structure will tell you how elementary and important that is.
One of the greatest scientists of the last century for sure. Francis Crick, another phenomenal scientist, whose explanation of the genetic code being a triplet code with three DNA molecules coding for one amino acid, in a degenerate code revolutionized chemistry and biology and our very understanding of the basic molecules of life.
Crick changed his area of research every ten years or so, and contributed phenomenally to anything he studied. His last efforts before he died he was studying the nature of consciousness. Sydney Brenner who won the Nobel in medicine for his genetics work on organ development and programmed cell death could have shared one with Crick for working out the genetic code with him.
This is just the starting of the list. Can you think of a few more names that could easily make this list? And include Economics in this list too. Labels: science and technology. Monday, January 09, And how do teachers become accountable? Most of us know that the state of education or even literacy, which is a very different thing in India is abysmal.
Most of us have different opinions on why this is so, and different opinions on how to fix it. There are grand suggestions that all education in India be privatized since parents prefer private schools anyway, given that most government schools are pathetic. Some others want higher salaries and better options for teachers.
The first suggestion, of superceding the government completely in all education is quite impractical. In fact, the countries with the best educational levels have excellent public school systems even the United States which does serve especially the neglected or poorest sections of society. The money spent is probably not going to reach its destination. And it would be against basic liberties to require private schools to bear the burden of mass education.
As far as the third goes, actually government teachers are rather well paid. A teacher can expect to earn about Rs. Surprisingly, most private school teachers especially in smaller schools, which form the vast majority earn between Rs. Yet, their performance is far better. Why is that? At a very basic level with out going in to other aspects it boils down to two factors: accountability and power.
The position is yours for keeps. Appointments are highly affected by political or organizational connections. There is little in place in terms of inspections with inspectors actually having the power to dismiss teachers. In contrast, in a private school, even for a teacher earning Rs a month, if the students perform badly, or there are clear cases of incompetence, the teacher is sacked. How good the education they impart is, that is a different matter. Government school teachers also happen to be extremely powerful. Because amongst other things, they become election poll officials during elections.
And the schools under them become election polling booths. Clearly, the power they wield during an election is obvious. Power, and no accountability. But how can this be fixed? The government has a number of proven and successful options. The first is obviously greater involvement of parents in the running of schools. Accountability is enforced, and learning indexes dramatically improve.
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The parents would be free to enroll their kids in any school, but those vouchers can only be used in lieu of school fees. If there is a surplus, it cannot be encashed. This way the money is used in education alone. There may be other options as well, that are just as successful. These have been successfully implemented in different parts of the world to varying degrees, and have been successful. Gurucharan Das and Amartya Sen are just a few amongst many who have argued for such reform in their columns or writing.
But how can any such policy be pushed forward in the Indian "system"? The teachers as a single entity are important for politicians, who are likely to be disinclined towards giving parents more control this could cost them their seats. If parent bodies are formed in villages, will they be truly democratic? Will the bureaucracy honestly handle a voucher scheme, or will it be mired in inefficiency and corruption? Will teachers themselves try to oppose a voucher scheme since that means the school will have to shape up or close down.
Open forum: How can these basic changes be implemented within the Indian system? These changes I believe are far more important and effective and likely to have bigger consequences than privatizing all education, or doubling the spending on education. Labels: culture and society , development. Friday, January 06, Happy hour: the best science fiction last year in the movies. Serenity : This was certainly one of the surprise packages of the year, and my pick for the most satisfying sci-fi flick of the year.
It came with no expectations. I almost thought it would turn out to be a B-grade sci-fi flick, or just a glorified serial that should never have left the SciFi channel, but it turned out to be a fairly entertaining flick with some interesting concepts and a predictable but entertaining plot. This is an old fashioned science fiction movie, about a large Alliance ruling the galaxy, who want things their way, and every one placid but happy, and a bunch of rebels who want people to be thinking, different, human individuals. River Tam, now rescued from the Alliance mind washers by her brother, and is the link between the Alliance and the rebels, and holds the answer to their questions as well.
Excellent stuff. War of the worlds : This was one of H. It came with a reputation, and lots of expectations. It needed something special. Spielberg tried to make it special, and partly succeeded. The movie had fantastic special effects. The aliens and their spaceships were superb. The screenplay was tight and fast. Biocompatible Materials. Genetic Phenomena. Conservation of Natural Resources. Tschaplinski, T.
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