Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The geometry of randomness

08.03.2010
Geometric factors can have a strong influence on the seemingly random walk of objects across pores in a thin membrane

When a butterfly flaps its wings in Europe, a storm may be caused in Asia. This often-used metaphor illustrates the strong resonances that may occur in random physical systems. Indeed, in systems affected by random effects, the influence of stimuli, such as external forces, on the eventual outcome is often poorly understood.

An international team of researchers working at the RIKEN Advanced Science Institute in Wako has now discovered that geometric factors can play an important role in random processes such as the movement of a particle through a cell membrane.

One particular consequence of random effects is stochastic resonance, where the movement of an object between two states—for example, across a membrane partitioning a box—depends on the external force, or ‘noise’ applied to the system. Certain levels of noise may even amplify the response of the system, so that the particle in the box travels faster from left to right. “Stochastic resonance is a common effect in electrical circuits or in biological sensory organs, where it is used to increase the system’s response,” says Franco Nori, who led the research team.

Stochastic resonance is a purely random effect, although the size and shape of a variety of constrained biological systems, such as pores or channels, can influence the response of the system, according to team member Pulak Kumar Ghosh.

The researchers therefore studied the influence of geometrical effects on stochastic resonance. “We considered systems where the membrane has different pore geometries,” says Fabio Marchesoni, also from the team. In order to stimulate a geometric response, the researchers simulated the effect of an oscillating force perpendicular to the membrane that shakes the particles back and forth. Previous studies of stochastic resonance effects showed that a force that produces no net movement should have no influence on the particle transport. Yet, Nori and colleagues observed a strong influence on the frequency of the driving force as well as its amplitude. In addition, the shape of the membrane and that of the surrounding cavities plays a role in the efficiency of the particle transfer.

Owing to the geometric dependence of this effect, the researchers have coined it ‘geometric stochastic resonance’, and expect to find it in certain physical systems. Team member Sergey Savel’ev suggests that, “the transport of magnetic fields across superconducting samples with thin barriers may be a good first experimental example that demonstrates geometric stochastic resonance.”

The corresponding author for this highlight is based at the Digital Materials Team, RIKEN Advanced Science Institute

Journal information
Ghosh, P.K., Marchesoni, F., Savel’ev, S.E. & Nori, F. Geometric stochastic resonance. Physical Review Letters 104, 020601 (2010)

Saeko Okada | Research asia research news
Further information:
http://www.rikenresearch.riken.jp/eng/research/6206
http://www.researchsea.com

More articles from Life Sciences:

nachricht Study shines light on brain cells that coordinate movement
26.06.2017 | University of Washington Health Sciences/UW Medicine

nachricht New insight into a central biological dogma on ion transport
26.06.2017 | Aarhus University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Study shines light on brain cells that coordinate movement

26.06.2017 | Life Sciences

Smooth propagation of spin waves using gold

26.06.2017 | Physics and Astronomy

Switchable DNA mini-machines store information

26.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>