AAAI Fall Symposium - Nov. 5 - 7, 2009 - Arlington, VA

Complex Adaptive Systems and the Threshold Effect: Views from the Natural and Social Sciences

Most interesting phenomena in natural and social systems include constant transitions and oscillations among their various phases. Wars, companies, societies, markets, and humans rarely stay in a stable, predictable state for long. Randomness, power laws, and human behavior ensure that the future is both unknown and challenging. How do events unfold ? When do they take hold ? Why do some initial events cause an avalanche while others do not ? What characterizes these events ? What are the thresholds that differentiate a sea change from a non-event ?

Complex Adaptive Systems have proven to be a powerful tool for exploring these and other related phenomena. We characterize a general CAS model as having a large number of self-similar agents that:

1. utilize one or more levels of feedback;
2. exhibit emergent properties and self-organization; and
3. produce non-linear dynamic behavior.

Advances in modeling and computing technology have led not only to a deeper understanding of complex systems in many areas, but they have also raised the possibility that similar fundamental principles may be at work across these systems, even though the underlying principles may manifest themselves differently.

Econophysicist Predicts Date of Chinese Stock Market Collapse

The Shanghai Composite Index was supposed to burst before July 27 but didn't. A few days after that deadline, however, it dropped by 20 percent. Coincidence ?.

Last month, we looked at a prediction that the Shanghai Composite stock market index was about to crash. The forecast was made by a team lead by the econophysicist Didier Sornette at the Swiss Federal Institute of Technology in Zurich, who has made a study of economic bubbles and how they burst. His thinking is that bubbles are the result of some kind of feedback mechanism that creates faster-than-exponential growth. This kind of growth rate is straightforward to measure, and so bubbles should be easy to identify. In July, he and his buddies pointed out that the Shanghai Composite stock market index was following exactly this kind of trend. But they also made an extraordinary prediction. They said that this bubble would burst between July 17 and 27.

IBM looks to DNA to sustain Moore's Law

Low concentrations of triangular DNA origami bind to wide lines on a lithographically patterned surface. Credit: PRNewsFoto/IBM.

As chip geometries get infinitesimally small, IBM is looking to DNA to make the manufacture of future chips feasible. On Monday, IBM researchers and collaborator Paul W.K. Rothemund, of the California Institute of Technology, announced an advancement of a method to arrange DNA origami structures on surfaces compatible with today's semiconductor manufacturing equipment.  The cost involved in shrinking (chip) features to improve performance is a limiting factor in keeping pace with Moore's Law and a concern across the semiconductor industry,  said Spike Narayan, a manager in the Science & Technology division of IBM Research, in a statement. Moore's Law, named after Intel co-founder Gordon Moore, states that the number of transistors that can be placed on an integrated circuit doubles roughly every two years. For more than four decades, chip manufacturers have been able to consistently shrink chip geometries, allowing Moore's Law to remain on track.

A coincidence of errors: Critical exponent for the quantum Hall transition

One of the most studied problems in the last twenty years is the integer quantum Hall effect, which describes the response of electrons confined in two-dimensions to a strong perpendicular magnetic field: The electrons move in circular orbits that fill bands, called Landau levels, and the Hall conductance ( i.e., the conductance perpendicular to an induced current ) of the electrons is quantized.

Like any phase transition, the change of the Hall conductance between quantized values ( as the electrons are moved between Landau levels by an external voltage or magnetic field ) can be described by a critical exponent, ν. Both numerical calculations and experiment agree fairly well about the value of ν.

But as Keith Slevin at Osaka University and Tomi Ohtsuki at Sophia University, both in Japan, argue in a Rapid Communication appearing in Physical Review B, this may be because of a coincidence of errors. Namely, numerical calculations have so far ignored Coulomb interactions between electrons, which should in fact be important, while the experimentally measured value of ν is based on approximations.

Quarks, gluons and corroborating E = mc2

It's taken more than a century, but Einstein's celebrated formula E = mc² has finally been corroborated, thanks to a heroic computational effort by French, German and Hungarian physicists. A brainpower consortium led by Laurent Lellouch of France's Centre for Theoretical Physics, using some of the world's mightiest supercomputers, have set down the calculations for estimating the mass of protons and neutrons, the particles at the nucleus of atoms.

Escuela Franco-Venezolana de Nanotecnología 2009 ( ENANO2009 ) del 2 al 6 de noviembre de 2009 en Caracas y Choroní, Venezuela

Contacto

http://www.redvnano.org/congreso/contactanos.html

La Red Venezolana de Nanotecnología está ayudando a organizar la Escuela Franco-Venezolana de Nanotecnología 2009 ( ENANO2009 ) del 2 al 6 de noviembre de 2009 en Caracas y Choroní ( Venezuela ), bajo el patrocinio de:

• FONACIT
• Programa de Cooperación de Postgraduados ( PCP )
• Embajada de Francia en Caracas
• Fundación IDEA
• Academia de Ciencias Físicas, Matemáticas y Naturales
• Universidad Central de Venezuela

Para el primer día del evento ( 2/11/09 ) se ha programado una jornada en la Fundación IDEA ( Caracas, Venezuela ) en la cual varios investigadores presentarán los desarrollos obtenidos fruto de la cooperación franco-venezolana en nanociencia y nanotecnología, gracias al apoyo de las herramientas de cooperación científica entre estos dos países.

El Comité Organizador de la ENANO2009 también ha programado sesiones de cursos, charlas y carteles del 3 al 6 de noviembre de 2009. Esta segunda parte de la Escuela tendrá lugar en Choroní, Edo. Aragua. Las sesiones van dirigidas a estudiantes e investigadores sensibles al desarrollo de estos conocimientos en Venezuela.

Se programarán además mesas de trabajo sobre aspectos asociados al programa de doctorado interinstitucional de nanotecnología que la Red se encuentra promoviendo, la cooperación nacional e internacional en actividades de I+D+i dirigidas a atender los problemas de interés nacional, la definición de mecanismos que faciliten la comunicación entre el sector científico, productivo y la sociedad en general.

Formalismo de Keldysh (Keldysh Technique)

This technique provides the correct evaluation of the quantum mechanical average of an observable. It means that there is not any assumption about the final system state whenever we perform the above mentioned average. As a consequence, it is a suitable tool to study small systems in contact with macroscopic systems which are in "different" thermodynamic equilibrium states.

See the original Keldysh's papers:

• L. V. Keldysh, ZhEFT 47, 1515 (1964)
• L. V. Keldysh, Soviet Physics JEPT 20, 1018 (1965)

Drop in world temperatures fuels global warming debate

Official government measurements show that the world's temperature has cooled a bit since reaching its most recent peak in 1998. That's given global warming skeptics new ammunition to attack the prevailing theory of climate change. The skeptics argue that the current stretch of slightly cooler temperatures means that costly measures to limit carbon dioxide emissions are ill-founded and unnecessary. Proposals to combat global warming are "crazy" and will "destroy more than a million good American jobs and increase the average family's annual energy bill by at least $1,500 a year," the Heartland Institute, a conservative research organization based in Chicago, declared in full-page newspaper ads earlier this summer. "High levels of carbon dioxide actually benefit wildlife and human health," the ads asserted.

DNA Evidence Can Be Fabricated, Scientists Show

Scientists in Israel have demonstrated that it is possible to fabricate DNA evidence, undermining the credibility of what has been considered the gold standard of proof in criminal cases. The scientists fabricated blood and saliva samples containing DNA from a person other than the donor of the blood and saliva. They also showed that if they had access to a DNA profile in a database, they could construct a sample of DNA to match that profile without obtaining any tissue from that person. “You can just engineer a crime scene,” said Dan Frumkin, lead author of the paper, which has been published online by the journal Forensic Science International: Genetics. “Any biology undergraduate could perform this.”