The caffeine hit that leaves coffee drinkers wide-eyed and alert isn’t the only way to get the brain revved up. It turns out that electrical brain stimulation also boosts cognitive function.

Cranking the central thalamus of rat brains with low-power, high-frequency electrical current boosted the critters’ object recognition memory, exploratory behavior and grooming, indicating heightened cognitive performance.

The technique, which boosts neural activity and related gene expression involved in maintaining an alert state, could be a treatment for some cognitive disabilities.

Turning theory into practice — or at least a demo — scientists have created an invisibility cloak. The shield, a set of metamaterial concentric rings, bends microwaves around objects. The device only works in a narrow band of frequencies, only in two dimensions and not perfectly, but it shows that the concept is, well, more than just theory.

An experimental digital camera captures images with a single pixel. Even the cheapest of mass-produced digital cameras have millions of pixels. The trick is that the light bounces off a chip containing nearly 800,000 movable microscopic mirrors. A series of 10,000 exposures with different, random arrangements of the mirrors gives a computer enough information to construct an image. The advantage is simpler hardware and much lower power use. A Physics News Update story has more details.

A gel stops surgical wound bleeding in laboratory animals within 15 seconds without causing damage. The liquid bandage, made from peptides that automatically assemble into nanofibers, promises to shorten surgical procedures and reduce the amount of blood needed by patients.

In forecasting the effects of global warming there are generally two scenarios, bad and very bad.

A study by the Northeast Climate Impacts Assessment, a collaboration between the Union of Concerned Scientists and a team of independent scientists from universities across the US, plots the effects of global warming on the Northeast in two cases: changing to clean, renewable energy sources and continuing to use fossil fuels.

In the first scenario, temperatures rise 3.5 to 6.5 degrees Fahrenheit by the end of the century, the number of days over 100 degrees in Northeast cities increases from one or two to three to nine, the number of days with snow on the ground decreases 25 percent and the frequency of extreme rainstorms increases ten percent.

In the second scenario, temperatures rise 6.5 to 12.5 degrees Fahrenheit by the end of the century, the number of days over 100 degrees in Northeast cities increases to 14 to 28 and the number of days with snow on the ground decreases by 50 percent. One-to-three-month droughts increase from every two or three years to yearly, and three-to-six-month droughts increase from none or every 15 years to once every 10 years.