PASS Scripta Varia 21 - Pontifical Academy of Sciences

COMMEMORATIONS OF DECEASED ACADEMICIANS
of it. Heisenberg knew nothing about what it would be, but warned and
said, well, maybe they are matrices because for matrices the commutative
laws of multiplications did not hold. Then people found it couldn’t be matrices
because, if you take a trace of a commutator it is always zero, so you
have a contradiction. Then people said, perhaps they are just abstract operators.
However, this didn’t help because the operators can be shown as not
to be bounded. Unbounded operators lead to a lot of mathematical complications.
The best tool in this game is the coherent states that come from
these commutation relations. And this is, again, one of the fields where Marcus
Moshinsky was very active.
In summary, I would say he was a master in all theoretical physics of the
20 th century and therefore he was just the man that a country like Mexico
needed. Although he was not Mexican by origin, he was born in the
Ukraine, I think he became one of the dominant figures of South American
theoretical physics altogether and I think it’s well deserved that he became
almost a cult figure in Mexico.
Walter E. Thirring
Marshall Nirenberg († 15.I.2010)
Marshall Nirenberg was born in New York on 10 April 1927 and died
this year, on 15 January 2010. As a child he was diagnosed with rheumatic
fever and, because of this, the family moved to Florida. In due course he
studied for his undergraduate degree at the University of Florida in
Gainesville and did his Ph.D. in biochemistry in 1957, at the University of
Michigan in Ann Harbor. He joined the National Institutes of Health
shortly after and devoted his research to the relationship between DNA,
RNA and proteins, and more specifically, to deciphering the genetic code.
I would now like to tell you an anecdote of this period, in which I was
directly involved. I was at the NIH at that time, as a professor on sabbatical,
and one day Marshall came to my lab and asked me whether by chance I
had some poly-L-phenyl-alanine. I answered him that I did not have any,
but when he asked me whether I knew in which solvent poly-L-phenylalanine
was soluble, I looked up a paper which I had published some years
earlier in JACS, on mechanism of polymerization, and found that poly-Lphenylalanine
was not soluble, even in such strong solvents as dimethylformamide
and dimethylsulfoxide, but was soluble in a saturated solution of
hydrogen bromide (HBr) in glacial acetic acid. Such a reagent is used to remove
blocking groups such as carbobenzoxy from amino functions, and is
38 The Scientific Legacy of the 20 th Century