Biology Reference
In-Depth Information
Center, Goad collaborated extensively with the physical chemist John R.
Cann, examining transport processes in biological systems. First with
electrophoresis gels, and then extending their work to ultracentrifuga-
tion, chromatography, and gel fi ltration, Goad and Cann developed
models for understanding how biological molecules moved through
complex environments. 40 The general approach to such problems was to
write down a set of differential or difference equations that could then
be solved using numerical methods on a computer. This work was done
on the IBM-704 and IBM-7094 machines at Los Alamos. These kinds of
transport problems are remarkably similar to the kinds of physics that
Goad had contributed to the hydrogen bomb: instead of neutrons mov-
ing through a supercritical plasma, the equations now had to represent
macromolecules moving through a space fi lled with other molecules. 41
Here too, it was not the motion of any particular molecule that was
of interest, but the statistical or average motion of an ensemble of mol-
ecules. Such work often proceeded by treating the motion of the mol-
ecule as a random walk and then simulating the overall motion com-
putationally using Monte Carlo methods. Goad himself saw some clear
continuities between his work in physics and his work in biology. Re-
porting his professional interests in 1974, he wrote, “Statistics and sta-
tistical mechanics, transport processes, and fl uid mechanics, especially
as applied to biological and chemical phenomena.” 42 By 1974, Goad
was devoting most of his time to biological problems, but “statistical
mechanics, transport processes, and fl uid mechanics” well described his
work in theoretical physics too. Likewise, in a Los Alamos memo from
1972, Goad argued that the work in biology should not be split off from
the Theoretical Division's other activities: “Nearly all of the problems
that engage [Los Alamos] have a common core: . . . the focus is on
the behavior of macroelements of the system, the behavior of micro-
elements being averaged over—as in an equation of state—or otherwise
statistically characterized.” 43 Goad's work may have dealt with proteins
instead of nucleons, but his modes of thinking and working were very
similar. His biology drew on familiar tools, particularly the computer,
to solve problems by deducing the statistical properties of complex sys-
tems. The computer was the vital tool here because it could keep track
of and summarize the vast amounts of data present in these models.
Los Alamos provided a uniquely suitable context for this work.
The laboratory's long-standing interest in biology and medicine—and
particularly in molecular genetics—provided some context for Goad's
forays. Few biologists were trained in the quantitative, statistical, and
numerical methods that Goad could deploy; even fewer had access to
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