The story of scientific advancement is rarely one of leaps and bounds. More often than not it’s evolution over revolution , and the story of the so-called ytterbium atomic clock fits that bill perfectly. You may remember that in July researchers improved upon the standard, cesium-powered atomic clock model by using a network of lasers to trap and excite strontium ; instead of losing a second every few years, the Optical Lattice Clock only lost a second every three centuries. Researchers at the National Institute of Standards and Technology made a pretty simple tweak to that model: replace the strontium with ytterbium and, voilà, another ten-fold increase in stability. Ten thousand of the rare-earth atoms are held in place, cooled to 10 microKelvin (just a few millionths of a degree above absolute zero) and excited by a laser “tick” 518 trillion times per second. Whereas the average cesium atomic clock must run for roughly five days to achieve its comparatively paltry level of consistency, the ytterbium clock reaches peak stability in just a single second. That stability doesn’t necessarily translate into accuracy, but chances are good that it will. That could could mean more accurate measurements of how gravity effects time and lead to improvements in accuracy for GPS or its future equivalents. The next steps are pretty clear, though hardly simple: to see how much farther the accuracy and stability can be pushed, then shrink the clock down to a size that could fit on a satellite or space ship. The one currently in use at the NIST is roughly the size of a large dinning room table. Filed under: Science , Alt Comments Via: AFP

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Scientists set new stabilty record with ytterbium atomic clock

There’s nothing quite like a 180 , and that’s what Pandora plans to pull as next month rolls in. The outfit’s 40-hour mobile listening limit, which was established back in February, will be history in September. The move was announced today by CFO Mike Herring, as he stated the following: “When we introduced the 40 hour mobile listening limit, we were confident that our scale — over 7 percent of total radio listening and Pandora’s number one ranking in most major markets — would allow us to take this action without impacting our key monetization initiatives in driving the disruption of the radio advertising market and driving our mobile advertising leadership. As our results have shown, the continued strong growth in our advertising revenue allowed us to cover the increased royalty costs with dollars left over to invest back into the business. With these tools in hand, and insight into how they work, we are resetting our levers in September. Notably, Pandora plans to eliminate the blanket 40-hour-per-month limit on free mobile listening effective September 1st. In the 6 months since we first implemented the free mobile listening limitation, we have gained critical insights into our user population that has given us greater control of our business. Because of these insights Pandora has implemented both other surgical levers to control content cost and new features that will allow for greater product usage.” It’s not clear why the the reversal is being made — be it uproar from loyal users or something else entirely — but those who found themselves perturbed by such a notion will have plenty to celebrate in just a few days. Filed under: Home Entertainment Comments Source: TechCrunch

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Pandora will remove 40-hour mobile listening limit next month