Slashdot Mirror
Domain: arxivblog.com
Stories and comments across the archive that link to arxivblog.com.
Stories · 108
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The Gap Between Stats and Understanding In Flu Cases
KentuckyFC writes "Bird flu gets all the headlines but ordinary flu kills several orders of magnitude more people each year and represents a significant threat to our society. The frightening thing about ordinary flu is how little we understand about how it spreads. According to a report at the physics arXiv blog, researchers trying to model this process say they still don't know some basic probabilities associated with infection (pdf, abstract). For instance, given that the disease has manifested itself clinically in an individual, what are the chances of that person dying? And if a virus can be caught from a number of different host species (as it might eventually be with bird flu) what is the probability of transmission?" -
First Image Taken With an Ultra Low Field MRI
KentuckyFC writes "MRI machines are about to get smaller, much smaller. Most of their bulk is taken up by the huge superconducting magnets required to generate fields of a few Teslas. Now a team at the Los Alamos National Lab in New Mexico has built a machine that can produce images using a field of only a few microTesla (PDF, abstract here). So giant superconducting magnets aren't necessary, a development that has the potential to make MRI machines much smaller, perhaps even suitcase-sized. The one-page paper shows sections of the first 3D brain image taken with the device." -
Time Dimension To Become Space-like
KentuckyFC writes "The Universe is about to flip from having three dimensions of space and one of time to having four dimensions of space. That's the conclusion of a group of Spanish astrophysicists who have calculated that observers inside such a Universe would see it expanding and accelerating away from them just before the flip (abstract, full paper pdf on the physics arXiv). 'We show that regular changes of signature on brane-worlds in AdS bulks may account for some types of the recently fashionable sudden singularities. Therefore, the fact that the Universe seems to approach a future sudden singularity at an accelerated rate of expansion might simply be an indication that our braneworld is about to change from Lorentzian to Euclidean signature. Both the brane and the bulk remain fully regular everywhere.'" Update: 10/09 16:06 GMT by Z : A few readers have written in to point out that the article is not peer-reviewed; your mileage may vary. -
Time Dimension To Become Space-like
KentuckyFC writes "The Universe is about to flip from having three dimensions of space and one of time to having four dimensions of space. That's the conclusion of a group of Spanish astrophysicists who have calculated that observers inside such a Universe would see it expanding and accelerating away from them just before the flip (abstract, full paper pdf on the physics arXiv). 'We show that regular changes of signature on brane-worlds in AdS bulks may account for some types of the recently fashionable sudden singularities. Therefore, the fact that the Universe seems to approach a future sudden singularity at an accelerated rate of expansion might simply be an indication that our braneworld is about to change from Lorentzian to Euclidean signature. Both the brane and the bulk remain fully regular everywhere.'" Update: 10/09 16:06 GMT by Z : A few readers have written in to point out that the article is not peer-reviewed; your mileage may vary. -
200,000 Elliptical Galaxies Point the Same Way
KentuckyFC sends us to arXiv, as is his wont, for a paper (abstract; PDF preprint) making the claim that 200,000 elliptical galaxies are aligned in the same direction; the signal for this alignment stands out at 13 standard deviations. This axis is the same as the controversial alignment found in the cosmic microwave background by the WMAP spacecraft. -
Gamma Rays From Thunderclouds
KentuckyFC sends us a report of gamma rays detected at a Japanese nuclear plant, whose origin was thunderclouds high overhead (abstract, article PDF). The theory is that showers of electrons caused by cosmic rays, when they encounter the high electric fields present in thunderstorm clouds, can be accelerated to energies above 10 MeV and result in bremsstrahlung photons detectable on the ground. -
Generating Nano Oscillatory Motion
KentuckyFC sends us to arxivblog.com, where he summarizes (in prose that is somewhat more twee than we usually encounter in writing about physics) the conversion of a constant force into oscillatory motion on the nano scale. Here is the article preprint. A research group at the University of Wisconsin-Madison has made mushroom-shaped nano-pillars that oscillate in a constant DC field, like metronomes. -
Generating Nano Oscillatory Motion
KentuckyFC sends us to arxivblog.com, where he summarizes (in prose that is somewhat more twee than we usually encounter in writing about physics) the conversion of a constant force into oscillatory motion on the nano scale. Here is the article preprint. A research group at the University of Wisconsin-Madison has made mushroom-shaped nano-pillars that oscillate in a constant DC field, like metronomes.