SLAC Today is available online at:
http://today.slac.stanford.edu
In this issue:
SLAC was Indispensable, says Nobel Prize Winner
Science Today: Subnuclear Scaling, Simplicity, and Supersymmetry
Stanford E-mail Server Change
Almanac Features SLAC Research

SLAC Today

Thursday - October 5, 2006

SLAC was Indispensable, says Nobel Prize Winner

(Image - Roger Kornberg)
Roger Kornberg
(Image courtesy of Linda A. Cicero, Stanford News Service.)

Upon receiving the Nobel Prize for Chemistry yesterday, Stanford Professor Roger Kornberg praised SLAC and the Stanford Synchrotron Radiation Laboratory facility. "We could not have solved the problem that was noted in the Nobel Prize announcement without the exceptional facilities given to us by SLAC. They were indispensable," Kornberg said.

Kornberg received the award for determining how DNA's genetic blueprint is read and subsequently used to direct the process for protein manufacture. Since the early 1990s, Kornberg has studied this transcription process at SSRL's Beamline 9-2 and 11-1. By passing the lab's extremely bright x-rays through crystallized proteins and watching how the x-rays scattered, Kornberg revealed the three-dimensional atomic structure of proteins in high resolution. The high level of detail in these images offered the first real understanding of the defining events of transcription.

"Congratulations to Dr. Roger Kornberg for his outstanding research," said Under Secretary for Science Raymond L. Orbach. "I am pleased and proud that the experimental work that led to Dr. Kornberg's Nobel Prize award took place at two Department of Energy funded synchrotron radiation laboratories. I congratulate all the staff at these two world-class laboratories on their high quality work." Read SLAC's press release...

(Daily Column - Science Today)

Subnuclear Scaling, Simplicity and Supersymmetry

(Image - Koch snowflake)
The Koch snowflake.
(Click on image for larger version.)

Imagine a world which looks exactly the same at every scale, no matter how much you magnify it. A simple representation of this kind of world is a fractal, like the Koch snowflake, which looks the same when magnified by any power of three.

The world of atoms—as well as nuclei, protons and neutrons—has a definite size, so it doesn't behave like this. But at distances much smaller than the radius of the proton, quarks and gluons behave almost this way.

In the theory of QCD (Quantum Chromodynamics), the interactions of quarks and gluons become weak at short distances. This property is known as asymptotic freedom. The interactions get weak quite slowly, however, so QCD is almost independent of scale.

The quasi-freedom of the quarks explained the dramatic "scaling" results of electron-proton scattering experiments performed at SLAC in the 1960s. But the scaling is not perfect, because residual interactions of the quarks cause them to change how they are distributed in the proton, as you look closer. The length of the curve around the Koch snowflake is an example of this phenomenon—when you look three times closer, the length increases by a factor of 4/3, because you see a new triangle where there was once a straight line.  Read more...

Changes to Campus
E-mail Spam Filters

Stanford Campus Computing announced this week that it will now automatically delete any e-mail messages with the highest spam rating. Currently, these messages are delivered to campus addresses with a subject beginning with [SPAM:#####]. This change applies only to campus e-mail addresses (@stanford.edu), not SLAC e-mail addresses (@slac.stanford.edu).

Stanford IT Services said this decision was made due to serious email delivery problems between September 26th and October 1st. They also reported that deleting spam helps to conserve University resources and to reduce load on their email servers in two ways. First, it allows them to not deliver spam to users (a direct reduction of load on the servers). In addition, since the spam was not delivered it is not part of their backup processes (this produces improved performance for the email backup process).

Stanford IT Services uses the same spam-tagging software as SLAC but they have locally tuned filters so the ratings for Campus tagged emails are not necessarily identical to those you might see on your spam messages held in the SLAC spam quarantine.

More information on the Stanford spam filter can be found here. More information on the SLAC spam filter is available here.

Almanac Features
SLAC Research

(Image - the Almanac)Yesterday's edition of The Almanac included three stories on SLAC research.

The editor of The Almanac would be delighted to receive feedback on these articles. You can do so through the paper's citizen journalism service, Town Square.

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