Luis Frigo luis at mobius.usfca.edu
Thu Nov 10 09:26:00 EST 1994

A digest of physics news items by Phillip F. Schewe, American
Institute of Physics
Number 202  November 9, 1994                   physnews at aip.org

SO-CALLED "JUNK" DNA, regions of genetic material (accounting
for 97% of the human genome) that do not provide blueprints for
proteins and therefore have no apparent purpose, have been puzzling
to scientists.  Now a new study shows that these non-coding
sequences seem to possess structural similarities to natural languages. 
This suggests that these "silent" DNA regions may carry biological
information, according to a statistical analysis of DNA fragments by
researchers at Boston University and Harvard Medical School (contact
H.E. Stanley of Boston University, 617-353-2617).  Studying DNA
sequences from humans, viruses, bacteria, yeast, and other
organisms, the researchers performed statistically-based linguistics
tests on the 37 known DNA sequences each having at least 50,000
"base pairs" or "letters" of DNA code.  The researchers first
performed a variation of a test known as Zipf analysis, in which the
words from a text are arranged on an x-axis from most frequently
occurring to least frequently occurring; plotted against their rank is
the actual number of occurrences of that word in the text.  For
natural languages one invariably gets a straight line (on a graph using
logarithmic axes) whose slope is about -1.  The non-coding DNA
sequences had linear slopes when base pairs were grouped into
genetic "words" consisting of 3, 6, 7, or 8 base pairs. Interestingly,
the slope values for non-coding sequences were closer to -1 than for
coding DNA, supporting a hypothesis that protein-coding DNA may
be more like a compressed computer file than a natural language. 
(R.N. Mantegna et al., upcoming article in Physical Review Letters.)

A NEARBY LARGE SPIRAL GALAXY not previously noted has
been discovered by astronomers using a telescope, the Dwingeloo
radio telescope in Holland, dedicated to searching for galaxies hidden
behind the disk and dust of our own galaxy.  The new galaxy, called
Dwingeloo 1, is about 10 million light years away.  Unlike the dwarf
galaxy found earlier this year in orbit around (and behind) the Milky
Way (see Update 174), Dwingeloo 1 is a large galaxy and is not
considered part of our local group of galaxies. The new observations
are part of a program to study a neglected part of the sky, a region
aptly called the "Zone of Avoidance" because astronomers scanning
extragalactic space had heretofore steered their telescopes away from
the haze of foreground stars constituting our galaxy.  (R.C. Kraan-
Korteweg et al., Nature, 3 Nov. 1994; this is Nature's 125th
anniversary issue; Happy Birthday.)

WHAT HAPPENED TO THE SSC STAFF?  A year after Congress
shut down the nascent supercollider, the number of scientists and
technicians dropped from 1100 to less than 100.  About a fourth are
jobless.  Some have returned to academe. Former SSC director Roy
Schwitters is now a physics professor at the University of Texas. 
About half of those who have found jobs are working outside particle
physics. Some examples: Cas Milner, who had worked on the
Gamma-Electron-Muon (GEM) detector at the SSC, now works at the
TIAA-CREF pension fund.  Kate Morgan (also formerly with GEM)
moved on to Citicorp.  (Science, 28 October 1994.)

-------------------------------\   |   /-------------------------------
   Luis Antonio Frigo  	        \  |  /     ~~~High LET Cosmic Rays~~~
   luis at physics.usfca.edu        \ | /	    Physics Research Laboratory
   lafrigo at lynx.cs.usfca.edu      \|/       University of San Francisco	
   Work Phone 510-666-2333         *        Golden Gate Ave. Cal U.S.A.

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