Ars Technica: The brain’s neurons encode information in the patterns and timing of spikes of activity. That encoding is hard to model using electronic hardware because most electronics use binary (“0″ and “1″) switches. However, researchers at HP labs have combined memristors and capacitors in a way that allows for the creation of spiking output patterns. Memristors are devices made of materials that behave as insulators until they are heated, at which point they act as conductors. The researchers at HP paired a memristor and a capacitor in a parallel circuit and applied a current. As the voltage heated it, the memristor behaved as a resistor until it reached a critical temperature; then it became a conductor. That switching allowed for full release of the energy stored in the capacitor and thus mimicked the spiking behavior of neurons. The system, which the researchers termed a neuristor, is a very simplified model of neuron behavior and produces a much more regular spiking pattern than a real neuron does. They believe that using a different memristor and a more complicated circuit could allow them to more closely reproduce neuron behavior on a computer chip.
New York Times: Helium is the second most abundant element in the universe, but a global shortage is disrupting a wide range of industries—including the balloon industry. The shortage is a result of a combination of factors. The decrease in natural gas prices has reduced gas refinery companies’ desire to try to profit from capturing helium, a byproduct of gas extraction. Other suppliers are having production problems with existing plants and with the construction of new ones. And finally, the US government, which keeps a reserve that provides 30% of the world’s helium, raised prices significantly in October. These factors have combined to create a shortage that industry analysts say is the worst ever in scale and duration. Some balloon companies have resorted to mixing helium and air, and others have simply been unable to meet customer requests. Medical imaging companies that use helium to cool magnets have also felt the impact of low supplies and higher costs. There is some concern for future availability in the helium industry as well. In 1996 the US government agreed to completely privatize its helium reserves by 2015.