Silicon Valley is mostly a world of practical technology—applying principles from pure science to create handy gadgets. But today, Hewlett Packard announced a new electrical component born of theoretical physics. The device, a nanoscale component called a "memristor," requires no power to retain data, which it can store more densely than a hard drive and access about as fast as a computer’s RAM memory—potentially allowing it to replace both components in the future.

Tagging has become a popular standard in Web content management. If you can enter a field of data somewhere, chances are good you can also attach tags. Tags let a user associate that data with a subject matter, much like a card catalogue in a library. When that user goes to retrieve the data, they need only remember a keyword or two to find it. All the posts on this blog, for instance, have tags to denote the topics covered. Social bookmarking sites allow users to tag their links. Photo sharing apps like Flickr do it as well. It's a helpful convenience for when you're out with a camera or in with a laptop.

Just imagine if you could tag everything you saw with your eyes in the course of a day.

Clinical psychologist Alain Brunet of McGill University in Montreal doesn’t usually torture his patients. But lately he has been pressing those with post-traumatic stress disorder, or PTSD, to relive emotionally scarring incidents. For some it’s rape, others battlefield trauma. When his patients get particularly upset—crying, shaking, blood pressure rising—he gives them a 25-year-old hypertension drug called propranolol. The idea, though, is not to lower their blood pressure.

PC Revival

Cost: $0-$260
Easy | | | | | Hard

• Start by checking the health of your hardware with a free diagnostic program such as #1-Tufftest (tufftest.com).
• If the motherboard or screen is shot, forget it. Replacing either one is more expensive and more hassle than buying a new system.
• Lost your user manual? Try the manufacturer’s Web site.
• Check eBay or craigslist.org for used replacement parts.