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Re: First-passage times in complex scale-invariant media

by Roger Bagula <rlbagula@[EMAIL PROTECTED] > Dec 4, 2007 at 03:48 AM

--- In physical_sciences@[EMAIL PROTECTED]
 "Robert Karl Stonjek" 
<stonjek@[EMAIL PROTECTED]
> wrote:

Fate might not be so unpredictable after all, study suggests

Why does it take so long for soul mates to find each other? How does 
disease spread through a person's body? When will the next computer 
virus attack your hard-drive?

A new theory published last month in Nature on the statistical concept 
of "First Passage Time," or FPT, may provide the key to answering at 
least a few of these questions, says theory co-author Prof. Joseph 
Klafter from Tel Aviv University's School of Chemistry. And the answers 
may lead to breakthroughs in medicine, mathematics, the environment, and 
elsewhere.

Prof. Klafter and his colleagues from the University of Pierre & Marie 
Curie in Paris (where he has been visiting professor) are the first to 
have developed an analytical model that calculates the average arrival 
time - the mean FPT - of a randomly-moving object in a complex
environment.

Understanding how randomly-moving objects arrive at a certain 
destination is no secret to scientists today. But no theory, until now, 
could predict the time it would take for an object to move between given 
addresses in a complex environment, like through the human body or the 
World Wide Web. Previous models only explained the passage of time when 
the event occurred in a homogenous environment, like in a vacuum or in a 
glass of water.

And in some instances, such as the movement of cancer cells in the human 
body, time is of the essence. The concept can best be understood by the 
question: How long will it take for a random walker to reach a certain 
destination"

Scientists from different backgrounds have studied and researched the 
predictability of FPT for decades. "Our new theory is exciting because 
it can be applied to a wide range of concepts in nature and 
mathematics," explains Prof. Klafter, the Heinemann Chair of Physical 
Chemistry at Tel Aviv University. "It can be used by biologists, by 
ecologists, and even help computer scientists predict when the next big 
virus will hit their computer."

When Prof. Klafter and his colleagues published their theory in Nature 
on November 1, they sparked interest from around the world - especially 
among biophysicists, who are looking for models to understand how long 
it takes for molecules to arrive at certain points in biological cells.

And although it will take months, maybe even years, for real-life 
experiments to prove the validity of this new theory, Prof. Klafter is 
looking forward to the results.

"I've received responses from researchers who are interested in using 
this model to analyze enzymes in cells," says Prof. Klafter. "Enzymes 
are im****tant for controlling functions in the body. If a biologist can 
estimate the FPT of a certain enzyme (at the place where this molecule 
reacts), then perhaps one could interfere with or manipulate the system 
to help prevent a disease or make a bodily function more efficient."

He adds, "This theory can be applied to anything that moves randomly. It 
can be used for predicting when an enzyme will reach a target cell, how 
long a hungry animal will forage for food when food when is scarce - or 
even how viruses spread through the Internet."

Source: American Friends of Tel Aviv University
http://www.physorg.com/news115917438.html

Posted by
Robert Karl Stonjek
 




 2 Posts in Topic:
First-passage times in complex scale-invariant media
Roger Bagula <rlbagula  2007-11-23 16:47:07 
Re: First-passage times in complex scale-invariant media
Roger Bagula <rlbagula  2007-12-04 03:48:36 

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