Apr. 30, 2013 ? Staring at a small patch of sky for more than 50 hours with the ultra-sensitive Karl G. Jansky Very Large Array (VLA), astronomers have for the first time identified discrete sources that account for nearly all the radio waves coming from distant galaxies. They found that about 63 percent of the background radio emission comes from galaxies with gorging black holes at their cores and the remaining 37 percent comes from galaxies that are rapidly forming stars.
"The sensitivity and resolution of the VLA, following its decade-long upgrade, made it possible to identify the specific objects responsible for nearly all of the radio background emission coming from beyond our own Milky Way Galaxy," said Jim Condon, of the National Radio Astronomy Observatory (NRAO). "Before we had this capability, we could not detect the numerous faint sources that produce much of the background emission," he added.
Previous studies had measured the amount of radio emission coming from the distant Universe, but had not been capable of attributing all the radio waves to specific objects. In earlier observations, emission from two or more faint objects often was blurred or blended into what appeared to be a single, stronger source of radio waves.
"Advancing technology has revealed more and more of the Universe to us over the past few decades, and our study shows individual objects that account for about 96 percent of the background radio emission coming from the distant Universe," Condon said. "The VLA now is a million times more sensitive than the radio telescopes that made landmark surveys of the sky in the 1960s," he added.
In February and March of 2012, Condon and his colleagues studied a region of sky that previously had been observed by the original, pre-upgrade, VLA, and by the Spitzer space telescope, which observes infrared light. They carefully analyzed and processed their data, then produced an image that showed the individual, radio-emitting objects within their field of view.
Their field of view, in the constellation Draco, encompassed about one-millionth of the whole sky. In that region, they identified about 2,000 discrete radio-emitting objects. That would indicate, the scientists said, that there are about 2 billion such objects in the whole sky. These are the objects that account for 96 percent of the background radio emission. However, the researchers pointed out, the remaining 4 percent of the radio emission could be coming from as many as 100 billion very faint objects.
Further analysis allowed the scientists to determine which of the objects are galaxies containing massive central black holes that are actively consuming surrounding material and which are galaxies undergoing rapid bursts of star formation. Their results indicate that, as previously proposed, the two types of galaxies evolved at the same rate in the early Universe.
"What radio astronomers have accomplished over the past few decades is analogous to advancing from the early Greek maps of the world that showed only the Mediterranean basin to the maps of today that show the whole world in exquisite detail," Condon said.
Condon worked with William Cotton, Edward Fomalont, Kenneth Kellermann, and Rick Perley of NRAO; Neal Miller of the University of Maryland; and Douglas Scott, Tessa Vernstrom, and Jasper Wall of the University of British Columbia. The researchers published their work in the Astrophysical Journal.
The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.
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EverSlide is a basic, but potentially very useful, hack built over the weekend at the TechCrunch Disrupt NY 2013 hackathon. As you might guess by the name, the service turns your Evernote notes into slideshow presentations. And it’s crazy simple to use, too. The first line of text in your Evernote note becomes the slide’s title, the second line becomes the slide’s content, and to create a second slide, you just insert a horizontal line from Evernote’s editing menu at the top. Then, boom, instant slideshow! The hack was created by computer science student Michelle Fernandez and Andrew Leung, who’s currently in between work. The team met at the hackathon, and said they got the idea for the project by reading the Evernote forums where employees had posted ideas for hacks. (And word has it, the Evernote staff here, too, got pretty excited for this idea as well – they told EverSlide’s founders that they talked about the hack amongst themselves for some fifteen minutes after hearing about the team’s plans.) The service is very minimal right now, given it was built over the weekend in between those midnight Nerf Gun wars and all, but the plan is to add more customization options in the future, including the ability to edit the fonts or colors of the text, perhaps, the ability to add photos, and more.
The Intel Core i5-3317U and four GB of memory are pretty standard specs for systems in this price range, The Acer Iconia W700-6465, HP EliteBook 2170p, and the Editor's Choice for high-end ultrabooks, the Asus Zenbook Prime Touch UX31A-BHI5T ($1199), all come with this setup. Therefore, it's no surprise that these systems all have similar CineBench, Handbrake, and Photoshop CS6 results. The HP lags behind the others in PCMark7, due to its spinning hard drive, but all are closely matched on the 3D tests, since they all have Intel HD Graphics 4000. 
Once you’ve had a few drinks at a bar it’s easy to let loose and blow off steam. Unfortunately, while you’re having fun, you could end up annoying others around you, namely the staff at the venue you’re at. By acting like a fool, you’re jeopardizing your future visits, since bartenders tend to remember who was a jerk and who was a great customer. A project at our Disrupt Hackathon called “Bar Power” is an app that will remind you to “not be a douchebag.” It’s somewhat of a game, walking you through nice things to do when you enter a bar. For example, the app will suggest that you say “hi” to the bartender and introduce yourself. If you do it and mark it?down in the app, you get some karma points. The really interesting part of the app comes into play when you’ve done something wrong. Did you drop a glass? Fall down? Mark that down, too. Naturally, you’ll lose those karma points that you gained by being the perfect customer. I chatted with the team who built it, Patricia Ju and Chris Baily, and they discussed their reasons for creating Bar Power, mostly stemming from Baily’s professional experience in the bar scene. While Bar Power might complicate what you’ve set out to do, which is drink, it is a good way to have a little fun and learn how to be a better customer. Ju explained: “It’s so much better to go out to places where you know people. Bartenders gave us feedback and that helped us make Bar Power’s rules. Once you’re in the app, you select the bar that you’re at and then start doing the nice things that it tells you to do. Slip up? Check that off on the list, too: The map below will track how you’re doing throughout the city, alerting you to areas that you should avoid since you were a freaking jerk the night before: As Baily explained, if people understand what to do and what not to do from the bartender community, their experience will be a better one. If the team can build relationships with venues to get them to interact with customers through the app, this could be a neat rating system that goes both ways, ? la?apps like Lyft and Uber. It sounds like Bar Power has potential past being “just a hack,” and I
