Which city will host the 2018 Winter Olympics?
In the 1950s, Niels Jerne, the famous Swiss immunologist, rocked the world of immunology to its core. At the time, there was a nearly unanimous consensus among immunologists that antibody formation was equivalent to a learning process in which the antigen played an instructive role. Antigens are usually proteins or polysaccharides that make up parts of cell surfaces. These cells can be microbes, such as bacteria or viruses, or nonmicrobial, such as pollen, or protein from transplanted organs, tissues or on the surface of transfused blood cells. Jerne suggested that instead of a specifically designed antibody being formed when an antigen presented itself, the body was born supplied with all the different types of antibodies that it was ever going to have: antigens were merely molecules that were recognized or selected by one of these innate antibodies. No instruction was going on, just selection. The complexity is built into the immune system, it doesn't become more so over time. His ideas are the foundation for what is now known about antibody response and clonal selection theory (the cloning, that is, the multiplying, of white blood cells with receptors that bind to invading antigens). Most of these antibodies will never encounter a matching foreign antigen, but those that do are activated and produce many clones of themselves to bind and inactivate the invading antigen.
Jerne kept on shaking things up. He later suggested that if the immune system works on this selection process, then most likely other systems do, too, including the brain. He wrote an article in 1967, entitled 'Antibodies and Learning: Selection versus Instruction', on the importance of viewing the brain as responding to selection processes and not to instruction: the brain was not an undifferentiated mass that could learn anything, just as the immune system was not an undifferentiated system that could produce any type of antibody. He made the startling suggestion that learning may actually be the process of sorting through pre-existing capacities that we innately possess to apply to a particular challenge facing us at a moment in time. In other words, these capacities are genetically determined neural networks specialized for particular kinds of learning. An oft-used example is that it is easy to learn to be afraid of snakes, while it is difficult to learn to be afraid of flowers. We have a built-in template that elicits a fear reaction when we detect certain types of motion, such as slithering in the grass, but no such innate reaction to flowers. Here, just as in the immune system, the idea is that complexity is built into the brain. The very important idea is that there is selection from pre-existing capacity. But it also implies constraints. If the capacity is not built-in, it does not exist.
The older model of the brain featured an undifferentiated mass ready to learn: any brain could learn anything. For such a brain, it would be as easy to teach it to enjoy the fragrance of roses as the stench of rotten eggs. Jerne's ideas challenged this conception and argued that the brain is built in a very specific way, which is genetically determined, and that we arrive from the baby factory mostly prewired.
What is the main topic of this passage?
1) Niels Jerne's radical medical ideas
2) Jerne's theory about antibody formation in immunology
3) Niels Jerne's views on learning and the structure of the brain
4) The connection between the immune system and the brain, as per Jerne
What was Niels Jerne's big idea as given in the first paragraph?
1) The immune system does not become more complex over time.
2) The immune system is much more complex than previously supposed.
3) Antibodies target specific antigens, rather than responding to all kinds of antigens at random.
4) Antibodies are present in the body from birth, rather than being formed in response to specific antigens.
What, according to the passage, is the similarity between the immune system and the brain?
1) Just as the immune system has the pre-existing capacity to produce any type of antibody, the brain has the inbuilt capacity to learn anything.
2) The immune system has a pre-existing set of antibodies from birth; similarly, the brain has an inborn set of mental templates that are applied when learning.
3) The immune system has the ability to select which antibody can be used with which antigen; in the same way, the brain can select which mental template to use when learning different things.
4) None of the above
What is the most likely source of this passage?
1) A scholarly article on antibody formation
2) A news item in a contemporary medical journal
3) A book on medical theories written in the 1980s
4) An extract from the biography of Niels Jerne
Just a quick doubt- What if I am not able to give the test during my booked slot time? Will it get converted to Unproctored mode?
can anyone tell percentiles plz..
heyy ... what is the CAT cutoff percentile for bimm ?
hi friends..i havea doubt regarding TISS..they have mentioned unemployed NC OBC.. does it mean only unemployed nc obc will get reservation in TISS? Somenone pls clarify..
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These AIMCATs are seriously driving me up the wall..What a waste of an exam and time! Scored 140...and I was so frustrated with the paper..I left with 15 mins to go..Never again TIME
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Hi guys, can you please suggest me the best mock test series for CAT 2014..
I needed some clarification regarding the score evaluation.
I am applying through GMAT but my exam date is on 1st Dec,2014. SP JAIN accepts scores only till Dec 2014. But since this would be my first GMAT attempt and I am not sure what scores I would get my query is suppose I do not get 650 on my first try but I send my scores to SP Jain and in my next attempts I clear the cutoffs by the time of score based interviews would I still be considered or scores only till Dec will be termed final?
hello puys!.. anybody having new tme 4 additional advanced sectionals?
A. When he does track down soothsayers he is disappointed or bored and worries about how much they are going to charge him.
B. His aim is to uncover pre-colonial spiritual and magical beliefs.
C. So it goes for the other countries he visits—Nigeria, Ghana, Côte d’Ivoire, Gabon and South Africa.
D. The shrines are “lavatorial and disagreeable”.
E. But the Africa he sees is a pretty filthy place.
i have a question, which classes you think is provider for best notes/study material for cet.
and if not classes study material than which kind of books would guarantee a good score?
i would also like you people to ask which is the best mock for cet
( i personally am thinking about IMS) whats ur opinion
Though its written 150 words, the space even allows 500 words for writing career goals or SOP. What impact will it have if somebody exceeds that limit, let say around 200 words ? Finding it difficult to keep it less than 150 words..!! TIA
Number of zeroes in a base N depends on the limiting prime contained in N.
In decimal system ie base 10=2*5, we look for the number of 5's in it.
Zeroes in 100! => [100/5]+[100/5^2] = 20+4=24
In base 7 = 1*7, so number of 7
In base 33=3*11, so number of 11
=> [100/11]= 9
But in case if 12=2^2*3 or 24=2^3*3,
Limiting primes are 2^2 and 2^3 respectively.
So number of zeroes in 100! In base 12=2^2*3
=> [100/2]+[100/2^2]+[100/ 2^3]+[100/2^4]+[100/2^5]+[100/ 2^6]= 97
So number of 2^2 => [97/2]= 48