Group items tagged

When I first heard about compressed sensing, I was skeptical. There were claims that it reduced the amount of data required to represent signals and images by huge factors and then restored the originals exactly. I knew from the Nyquist-Shannon sampling theorem that this is impossible. But after learning more about compressed sensing, I’ve come to realize that, under the right conditions, both the claims and the theorem are true. The Nyquist-Shannon sampling theorem states that to restore a signal exactly and uniquely, you need to have sampled with at least twice its frequency. Of course, this theorem is still valid; if you skip one byte in a signal or image of white noise, you can’t restore the original. But most interesting signals and images are not white noise. When represented in terms of appropriate basis functions, such as trig functions or wavelets, many signals have relatively few non-zero coefficients. In compressed (or compressive) sensing terminology, they are sparse.

Theodore Berger and his team at the USC Viterbi School of Engineering’s Department of Biomedical Engineering have developed a neural prosthesis for rats that is able to restore their ability to form long-term memories after they had been pharmacologically blocked.In a dramatic demonstration, Berger blocked the ability to rats to form long-term memories by using pharmacological agents to disrupt the neural circuitry that communicates between two subregions of the hippocampus, CA1 and CA3, which interact to create long-term memory, prior research has shown.

1,600-year-old St. Anthony's Monastery restoration took eight years to complete. The announcement comes a month after Egypt's worst incident of sectarian violence in over a decade. Amid the renovations, archaeologists discovered the remains of the original monk cells dating to the 4th century.

A team of archaeologists unearthed two large red granite statues in southern Egypt at the mortuary temple of one of the most powerful pharaohs, who ruled nearly 3,400 years ago, the Culture Ministry said Tuesday. A ministry statement said the team discovered a 13 foot (4 meter) statue of Thoth, the ancient god of wisdom and the top part of a statue of Pharaoh Amenhotep III standing next to another god. Both were found buried in the pharaoh's mortuary temple on the west bank of the Nile in the southern temple city of Luxor.