14,557 research outputs found
A Historical Perspective on Cancer
It is proposed that cancer results from the breakdown of universal control
mechanisms which developed in mutual association as part of the historical
process that brought individual cells together into multi-cellular communities.
By systematically comparing the genomes of uni-celled with multi-celled
organisms, one might be able to identify the most promising sites for
intervention aimed at restoring the damaged control mechanisms and thereby
arresting the cancer.Comment: 3 pages, plainTeX, no figure
Two Topics concerning Black Holes: Extremality of the Energy, Fractality of the Horizon
We treat two aspects of the physics of stationary black holes. First we prove
that the proportionality, d(energy) ~ d(area) for arbitrary perturbations
(``extended first law''), follows directly from an extremality theorem drawn
from earlier work. Second we consider quantum fluctuations in the shape of the
horizon, concluding heuristically that they exhibit a fractal character, with
order lambda fluctuations occurring on all scales lambda below M^{1/3} in
natural units.Comment: 18 pages, plainTeX, 2 postscript figures (Figures for automatic
inclusion are in a separate file which you should receive with the .tex file.
For instructions on decoding and including them (or omitting them to avoid
error messages if your system can't handle them) see the box at the beginning
of the tex file for this paper.
Is the spacetime metric Euclidean rather than Lorentzian?
My answer to the question in the title is "No". In support of this point of
view, we analyze some examples of saddle-point methods, especially as applied
to quantum "tunneling" in nonrelativistic particle mechanics and in cosmology.
Along the way we explore some of the interrelationships among different ways of
thinking about path-integrals and saddle-point approximations to them.Comment: plainTeX, 21 pages, 1 figure (in color). A few minor corrections and
some re-wording. A previous version erroneously gave Re(f(z)) rather than
Im(f(z)) (Thanks to Adam Brown for this correction.) Most current version is
available at
http://www.perimeterinstitute.ca/personal/rsorkin/some.papers/134.tunneling.pdf
(or wherever my home-page may be
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