The American Association for the Advancement of Science (AAAS) annual meeting kicks off in Washington today.
The seminar on nanotechnology features a bevy of big names and rising stars.
Intriguing topics among the meeting's 150 symposia, include making materials and devices the way nature would (Frontiers in Bioinspired Materials and Nanosystems), understanding and controlling the behavior of complicated systems like markets, social networks and living beings (Complex Adaptive Systems: Advances in Theory and Practice), the science of chance and uncertainty in biology, society and technology (The Pervasiveness of Extreme Events in Science), and a look at voting technology issues like network security, the integrity of all-electronic voting machines and voting machine design (Economics and Engineering, and Voting Technology: Current Assessment and Future Prospects, A Post-2004 Election Update).
The results from a survey distributed to scientists working for the U.S. Fish and Wildlife Service by the Union of Concerned Scientists and Public Employees for Environmental Responsibility are stark. Highlights:
Survey summary and links to the full survey ; U.S. Fish and Wildlife Service Website
Why is it that when someone tells a dog story, all the good dog stories you've ever heard come to mind? It probably has to do with avalanches of neural signals that researchers have observed in rat brain tissue. A new computer model shows that the avalanches are an efficient way to store information. For a sense of how avalanches work, see this explanation of the sandpile model. Why people find it so compelling to tell the same dog stories over and over is an entirely different question. So is this.
Researchers have shown that species diversity in nature has a lot to do with chaotic dynamics. Species diversity increases when inferior but fast species can exist in the same space as superior but relatively stationary species. The researchers found that a mathematical effect -- stochastic resonance -- can be used to predict when coexistence, and thus species diversity, can be increased.
Stochastic resonance describes a system that has a threshold, meaning a signal is not detected until it exceeds a minimum strength. Adding noise to this type of system increases the overall energy level of signals, boosting those that are otherwise too weak to be detected. Too much noise, however, swamps a signal.
So the key to increasing species diversity is increasing the mathematical noise, or randomness, of the system -- but only so much.
Drawing a line on climate
An International Climate Change Taskforce report has identified the point-of-no-return temperature for global warming. A global average 2 degrees Celsius above that of pre-industrial 1750 would bring on disastrous climate changes like widespread crop failure and sea-level rises, and increase the possibility of catastrophic changes like the Greenland ice sheet melting completely and the Gulf Stream stopping. The taskforce of US, UK and Australian government officials, including co-chair US Republican Senator Olympia Snowe, also pegged the concentration of atmospheric carbon dioxide that will make the two-degree rise inevitable: 400 parts per million.
Today's average global temperature is 0.8 degrees above the pre-industrial level; today's atmospheric carbon dioxide level is 379 parts per million; and at our current output the carbon dioxide level could cross the threshold within 10 years.
The report also includes a plan aimed at keeping the temperature rise in check. Highlights include raising public awareness of the problem; shifting subsidies from food crops to biofuels; phasing out fossil fuel subsidies; requiring financial institutions to adopt minimum efficiency standards for projects they support; and getting G8 countries to double alternative energy research, development and demonstration funding by 2010, shift one-quarter of their energy to renewable resources by 2025, and offer help to developing countries.
Meanwhile, a large-scale climate modeling study has found that the effects of greenhouse gases could be more severe than previously thought, with potential temperature increases ranging from 2 to 11 degrees Celsius rather than 2 to 6. A link to the full paper is here.
The project used more than 90,000 idle computers across the Internet to amass the large amount of compute power needed to better predict climate changes. Anyone with a computer can help the ongoing study by participating in climateprediction.net.
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