Navigation Links
New theory shows that neither birth nor death stops a flock
Date:2/24/2012

EUGENE, Ore. -- (Feb. 24, 2011) -- Neither births nor deaths stop the flocking of organisms. They just keep moving, says theoretical physicist John J. Toner of the University of Oregon. The notion, he says, has implications in biology and eventually could point to new cancer therapies.

Picture any scenario in which self-propelled organisms -- animals, birds, bacteria, molecules within cells, cancer cells, fish, and even tiny plastic rods on a vibrating table -- move as a swarm or flock in the same direction. Eighteen years ago, Toner co-developed two equations that together provide a complete theory of flocking for "immortal" flocks -- those in which creatures are not being born and dying while the moving.

Now he has extended that work to include the effects of birth and death.

The new equations are as complete a description of flocks as the Navier-Stokes equation is of fluid dynamics. This equation, named after French physicist and engineer Claude-Louis Navier and British scientist George Gabriel Stokes applies equally well to all fluids; air, water, honey and the oil from the Gulf of Mexico disaster are all described by it. All of the differences between these very different fluids can be incorporated into the Navier-Stokes equation by changing the value of one number, called "the viscosity." Large values apply to sticky fluids like honey and oil, while smaller values describe air and water.

The Navier-Stokes equation has been used successfully for more than a century in the design of aircraft, automobiles, plumbing and power stations.

Toner's equations likewise work for all flocks, and contain some numbers that must be adjusted to account for differences between different kinds of flocks. The earlier work on immortal flocks has been applied to the flocking behavior of birds, particularly studies of starlings in Rome by Andrea Cavagna and Irene Giardina.

In a new paper -- "Birth, Death, and Flight: A Theory of Malthusian Flocks," published in the Feb. 24 issue of the journal Physical Review Letters -- Toner shows that flocking is even robust against birth and death. The finding, he said, is especially important for many other organisms that flock, especially bacteria, which may contain millions of individuals that are constantly dying and being replaced by the reproduction of others as the swarm moves.

"A flock can keep moving in the same direction for times much longer than the lifetime of any individual member," said Toner, a member of the UO Institute of Theoretical Science and a professor in the physics department. "Individuals are being born and dying but their direction and motion can persist much longer than the lifetime of any individual creature."

Secondly, he added, the density changes of such a "mortal flock" -- where some members are leaving by death and joining by birth -- create persistent but predictable fluctuations. "Birth and death are very important in microbiological flocks, such as swarms of bacteria or in collections of self-propelled molecules that flock in most living cells."

This fundamental new knowledge already is applicable to understanding the movement of molecules within cells -- in particular, mitotic spindles that launch the machinery of cell development and division, Toner said.

In mitotic spindles, individual molecules live for only about 20 minutes, but spindles live and continue their work for days, he said. "The motion continues as dead molecules are replaced by newly synthesized molecules, as well as by molecules which immigrate in to take their places."

Through the application of his new theory to the study of mitotic spindles, Toner said, it may be possible to design specifically targeted cancer therapies that, unlike current chemotherapies, would only kill aberrant, or diseased cells, and allow desirable, healthy ones to live. "In reality, such applications are a long way off," said Toner, whose research is supported by the National Science Foundation.

"This study shows us how fundamental physics and mathematics deployed to explain an everyday occurrence in nature can spin off with potentially life-saving medical applications," said Kimberly Andrews Espy, vice president for research and innovation at the UO. "This cutting-edge research conducted at the University of Oregon is another great example of the widespread applications and potential benefits that basic research and the promise it holds to address the real problems of today and tomorrow."

In September, Toner will embark on a one-year sabbatical to do additional research on flocking, or collective behavior, at IBM Yorktown Heights and the University of California, Berkeley, under a fellowship from the New York City-based Simons Foundation.


'/>"/>

Contact: Jim Barlow
jebarlow@uoregon.edu
541-346-3481
University of Oregon
Source:Eurekalert  

Related biology news :

1. Radical theory explains the origin, evolution, and nature of life, challenges conventional wisdom
2. A new theory emerges for where some fish became 4-limbed creatures
3. Dinosaurs with killer claws yield new theory about flight
4. Polymer characterization tweezers turn Nobel theory into benchtop tool
5. Over the hump: Ecologists use power of network science to challenge long-held theory
6. New theory may shed light on dynamics of large-polymer liquids
7. Fulbright scholar takes ecological theory to Andean heights
8. New malaria protein structure upends theory of how cells grow and move
9. MIT control theory research: How to control complex networks
10. Scientists make bamboo tools to test theory explaining East Asias Stone Age tool scarcity
11. Human networking theory gives picture of infectious disease spread
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
New theory shows that neither birth nor death stops a flock
(Date:5/12/2016)... 2016 WearablesResearch.com , a brand of ... results from the Q1 wave of its quarterly wearables ... consumers, receptivity to a program where they would receive ... insurance company. "We were surprised to see ... Michael LaColla , CEO of Troubadour Research, "primarily because ...
(Date:5/3/2016)... May 3, 2016  Neurotechnology, a provider of ... MegaMatcher Automated Biometric Identification System (ABIS) , a ... projects. MegaMatcher ABIS can process multiple complex biometric ... combination of fingerprint, face or iris biometrics. It ... and MegaMatcher Accelerator , which have ...
(Date:4/28/2016)... First quarter 2016:   , ... the first quarter of 2015 The gross margin was ... 18.8) and the operating margin was 40% (-13) Earnings ... flow from operations was SEK 249.9 M (21.2) , ... SEK 7,000-8,500 M. The operating margin for 2016 is ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... ... June 23, 2016 , ... Mosio, a leader ... “Clinical Trials Patient Recruitment and Retention Tips.” Partnering with experienced clinical research professionals, ... providing practical tips, tools, and strategies for clinical researchers. , “The landscape of ...
(Date:6/23/2016)... SILVER SPRING, Md. , June 23, 2016 ... evidence collected from the crime scene to track the criminal ... sick, and the U.S. Food and Drug Administration (FDA) uses ... Sound far-fetched? It,s not. ... whole genome sequencing to support investigations of foodborne illnesses. Put ...
(Date:6/23/2016)... , June, 23, 2016  The Biodesign Challenge ... envision new ways to harness living systems and biotechnology, ... Art (MoMA) in New York City ... 130 participating students, showcased projects at MoMA,s Celeste Bartos ... Paola Antonelli , MoMA,s senior curator of architecture and ...
(Date:6/23/2016)... (PRWEB) , ... June 23, 2016 , ... In a ... Hospital in Denmark detail how a patient who developed lymphedema after being treated for ... The results could change the paradigm for dealing with this debilitating, frequent side effect ...
Breaking Biology Technology: