Scientists have created the sound of silence, an "acoustic cloak" that could one day block out the din of noisy neighbours.
Two teams have come up with a design of special materials that could cloak an object from sound and a third has already devised a scheme to create them, so sound waves travel seamlessly around them.
The work follows recent research on "invisibility cloaks", where a number of teams have shown that synthetic materials, called metamaterials - which are designed down to the microscopic level - can make beams of light flow around an object to make it invisible.
Science & Technology
When it comes to being misled, humans are no more sophisticated than ants or fish.
Implications for evacuations and how to guide people safely in an emergency will arise from the discovery that most of us are happy to play follow-my-leader, even if we are trailing after someone who does not know where they are going and taking the most meandering route.
Even more striking, even when we are shown a faster route, we prefer to stick with the old one and tell others to take the long road too, a finding that could have lethal implications when it comes to evacuating a building or ship in an emergency.
Implications for evacuations and how to guide people safely in an emergency will arise from the discovery that most of us are happy to play follow-my-leader, even if we are trailing after someone who does not know where they are going and taking the most meandering route.
Even more striking, even when we are shown a faster route, we prefer to stick with the old one and tell others to take the long road too, a finding that could have lethal implications when it comes to evacuating a building or ship in an emergency.
Scientists at UCL (University College London) have found the link between what we expect to see, and what our brain tells us we actually saw. The study, published in this week's PLoS Journal of Computational Biology, reveals that the context surrounding what we see is all important - sometimes overriding the evidence gathered by our eyes and even causing us to imagine things which aren't really there.
French archaeologists in Sudan say they have uncovered the oldest proof of human sacrifice in Africa, hailing the discovery as the biggest Neolithic find on the continent for years.
|
| ©Unknown |
| People will naturally 'flock' when they are unsure of the direction to travel. |
Have you ever arrived somewhere and wondered how you got there? Scientists at the University of Leeds believe they may have found the answer, with research that shows that humans flock like sheep and birds, subconsciously following a minority of individuals.
Results from a study at the University of Leeds show that it takes a minority of just five per cent to influence a crowd's direction - and that the other 95 per cent follow without realising it.
Contrary to our previous beliefs, identical twins are not genetically identical. This surprising finding is presented by American, Swedish, and Dutch scientists in a study being published today in the prestigious journal American Journal of Human Genetics. The finding may be of great significance for research on hereditary diseases and for the development of new diagnostic methods.
Using data from NASA's Chandra X-ray Observatory, scientists have reported the possible detection of a binary star system that was later destroyed in a supernova explosion. The new method they used provides great future promise for finding the detailed origin of these important cosmic events.
With the aid of computerized image analysis, it may be possible in the future for radiologists to feel images with the help of a three-dimensional mouse. Erik Vidholm at Uppsala University has been involved in developing the new technology, which makes it easier to diagnose and plan the treatment of cancer, for instance.
Computerized image analysis can be used to determine the size of organs like the liver, or to construct three-dimensional models of organs when surgery or radiation is being planned. The quality of these images often varies, however - what's more we humans can actually look very different from each other inside, which makes it difficult for the computer to find the information that is relevant fully automatically.
Computerized image analysis can be used to determine the size of organs like the liver, or to construct three-dimensional models of organs when surgery or radiation is being planned. The quality of these images often varies, however - what's more we humans can actually look very different from each other inside, which makes it difficult for the computer to find the information that is relevant fully automatically.
|
| ©Uppsala University |
| Adaptation of a computer model to an image of a liver. With the aid of the adapted model it is possible to measure the volume of the liver, for instance, or calculate changes in shape and migrations. |
An international team of astronomers has discovered two planets that resemble smaller versions of Jupiter and Saturn in a solar system nearly 5,000 light years away. The find suggests that our galaxy hosts many planetary systems like our own, said Scott Gaudi, assistant professor of astronomy at Ohio State University.
The two planets were revealed when the star they orbit crossed in front of a more distant star as seen from Earth. For a two-week period from late March through early April of 2006, the nearer star magnified the light shining from the farther star.
The two planets were revealed when the star they orbit crossed in front of a more distant star as seen from Earth. For a two-week period from late March through early April of 2006, the nearer star magnified the light shining from the farther star.
|
| ©Cheongho Han and colleagues at the Korea Astronomy and Space Science Institute |
| This artist's rendering of a distant solar system shows two newly discovered planets -- one resembling Jupiter (middle) and one resembling Saturn (middle right). Both planets orbit a star that is about half the size of our sun. The light from a more distant star (upper right) made the discovery possible, as it brightened and dimmed through a phenomenon called gravitational microlensing. Note: The rendering indicates the planets are closer to the source star than they actually are. |
© INFN
The hairs were placed in capsules and inserted in the core of the nuclear reactor in Pavia. The technique used is known as "neutron activation", which has two enormous advantages: it does not destroy the sample and it provides extremely precise results even on samples with an extremely small mass, such as human hair samples.
The hairs were placed in capsules and inserted in the core of the nuclear reactor in Pavia. The technique used is known as "neutron activation", which has two enormous advantages: it does not destroy the sample and it provides extremely precise results even on samples with an extremely small mass, such as human hair samples.
The physicists performing the study used a small nuclear reactor used exclusively for research purposes at the University of Pavia, applying techniques that were created for the project known as "Cuore" ("Heart"), which is being developed at the INFN's national laboratories in Gran Sasso.
The research, the results of which will be published in the journal Il Nuovo Saggiatore, was performed on hair samples that had been taken during different periods of Napoleon Bonaparte's life, from when he was a boy in Corsica, during his exile on the Island of Elba, on the day of his death (May 5, 1821) on the Island of Saint Helena, and on the day after his death.
Samples taken from the King of Rome (Napoleon's son) in the years 1812, 1816, 1821, and 1826, and samples from the Empress Josephine, collected upon her death in 1814, were also analysed. The hair samples were provided by the Glauco-Lombardi Museum in Parma (Italy), the Malmaison Museum in Paris, and the Napoleonic Museum in Rome. In addition to these "historical" hair samples, 10 hairs from living persons were examined for comparison purposes.
