TOP 100 CAMPING SITES
| |||
|
| |||
| |||
|
| |||
| Readers Respond on "Naked Singularities" End without Horizons?In “Naked Singularities,” Pankaj S. Joshi argues that models for stellar collapse can produce naked singularities, or singularities without the event horizon that surrounds a black hole. According to quantum theory, black holes emit thermal radiation and evaporate because of the separation of particle-antiparticle pairs near their event horizon. Will a naked singularity ever disappear? [More] rss.sciam.com |
What's on TV Is Biomedical Bonus [The following is an exact transcript of this podcast.]When TV sets die, they usually end up incinerated or in landfills. But now researchers from England’s University of York believe they’ve found a valuable use for told TVs--in medicine. [More] rss.sciam.com |
How the Brain Localizes Sounds We live in a world full of echoes. Sounds reverberate, bouncing off walls, buildings, rocks and any other nearby surface. These sound waves pile on one another and hurtle down your ear canals from different angles, the echoes from one noise jumbling together with new sounds and their echoes. In spite of that barrage, the neurons in the auditory midbrain, an area that responds before the auditory cortex does, are able to sort out which were the original sounds and where they came from. How they do so has long puzzled scientists, but new research suggests the trick is simpler than expected.In an April study, neuroscientists led by Sasha Devore at the Massachusetts Institute of Technology tested the widely held hypothesis that specialized cells in the brain actively suppress neuronal response to echoes. Using electrodes in a cat’s midbrain, researchers measured cells’ responses to a sound and its reverberations. They found that the cells that sense a sound’s direction of origin responded more strongly to the first 50 milliseconds of sound waves than they did to the later waves--their activity simply tapered off after the onset of the sound. The tapering response, a much simpler mechanism than the earlier theory of suppression, allows the brain to easily tune in to original sounds and pinpoint who or what is making noise. [More] rss.sciam.com |
Sewage Industry Fights Phosphorus Pollution Tucked away in Oregon’s Willamette Valley, three massive metal cones could help address the world’s dwindling supply of phosphorus, the crucial ingredient of fertilizers that has made modern agriculture possible. The cones make consistently high-quality, slow-release fertilizer pellets from phosphorus recovered at the Durham Advance Wastewater Treatment Facility, less than 10 miles from downtown Portland. By generating about one ton of pellets every day, they are changing the view that such recycling could not be done efficiently. Ostara, the firm that makes the reactors and sells the pellets as Crystal Green, thinks that Durham is one of hundreds of facilities that could use the technology.Humans excrete some 3.3 million tons of phosphorus annually. In fact, phosphorus from domestic sewage, in addition to fertilizer runoff, has traditionally been a nuisance, because it triggers blooms of algae that deplete local waters of oxygen. In some wastewater plants the element can also bind with ammonia and magnesium to form a mineral called struvite, which keeps phosphorus out of waterways but clogs pipes at the facilities. The growing recognition that cheap supplies of phosphorus will grow scarce in the coming decades has led some nations to consider conservation. Sweden has mandated that 60 percent of phosphate be recycled from wastewater by 2015. In 2008 China slapped a 135 percent export tariff on phosphate. [More] rss.sciam.com |
Historical Development: Could a Frozen Camera Dethrone Hillary and Norgay as the First to Summit Everest? On June 8, 1924, George Mallory and Andrew Irvine left their camp less than a kilometer from the summit of Mount Everest on a mission to be the first mountaineers to ascend the world's highest peak (8,850 meters). They were never to be heard from again. Whether either man reached the summit--almost three decades before Sir Edmund Hillary and Tenzing Norgay's historic 1953 climb--has been an open question for nearly 86 years. [More] rss.sciam.com |