Sunday, December 12, 2010

Modern man outlived Neanderthals due to 'live slow and grow old' strategy

Young Neanderthals' teeth growth was significantly faster than in our own species

Young Neanderthals' teeth growth was significantly faster than in our own species Photo: HULTON ARCHIVE

Humans became more sophisticated than other species because of our uniquely slow physical development and long childhood, it was claimed.

Other primates have shorter gestation, mature faster in childhood, reproduce at a younger age and have shorter lifespans, even when compared with early humans.

It had been unclear at what point in the six to seven million years since our evolutionary split from non-human primates the life course shifted.

But a new examination of teeth from 11 Neanderthal and early human fossils has suggested that our move from a "live fast and die young" to a "live slow and grow old" strategy occurred fairly recently.

The research was led by scientists at Harvard University in the United States, the Max Planck Institute for Evolutionary Biology (MPI-EVA), and the European Synchrotron Radiation Facility (ESRF).

Tanya Smith, assistant professor of human evolutionary biology at Harvard, said: "Teeth are remarkable time recorders, capturing each day of growth much like rings in trees reveal yearly progress.

"Even more impressive is the fact that our first molars contain a tiny 'birth certificate', and finding this birth line allows scientists to calculate exactly how old a juvenile was when it died."

Dr Smith and her colleagues found that young Neanderthals' teeth growth was significantly faster than in our own species, including some of the earliest groups of modern humans to leave Africa some 90,000 to 100,000 years ago.

This indicates that the elongation of childhood has been a relatively recent development.

The research was published in the Proceedings of the National Academy of Sciences.

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Saturday, December 11, 2010

Pedestrians struggle to suppress their inner lemming when crossing the road

Pedestrians crossing the road: Pedestrians struggle to suppress their inner lemming when crossing the road

The research showed that pedestrians were up to 2.5 times more likely cross a busy road if someone else stepped out in front of the traffic first Photo: GETTY

Biologists studying the herding instinct of humans have analysed the road crossing behaviour of pedestrians at a crossing in a busy city centre.

They found that pedestrians were up to 2.5 times more likely cross a busy road if someone else stepped out in front of the traffic first. Men were also more likely to follow others into the road than females.

In some cases individuals started to cross before scuttling back to the kerb after realising the danger they were in.

Dr Jolyon Faria, who was at Leeds University when he conducted the study but is now at Princeton University, said he was hoping to investigate how people respond to the behaviour of their neighbours in potentially dangerous situations.

He said: "Crossing the road is a dangerous scenario, so we thought it would be interesting to see whether people's behaviour was influenced by those on either side of them.

"There is a potential advantage to following others when they cross because when others cross the road it usually indicates a gap in the traffic and gives the benefit of getting across the road faster.

"The disadvantages are quite serious though you may be injured by a vehicle.

"It could be that people feel safer when they are crossing with others. Perhaps its an effect from our evolutionary past."

Dr Faria analysed the behaviour of 365 people as they waited to cross at a pedestrian crossing in Leeds during rush hour over a three-day period.

Using computer simulations he was also able to examine what would happen if the pedestrians chose to ignore those around them, or followed the lead of others in the group.

It revealed that the pedestrians were 1.5 to 2.5 times more likely to cross the road on average if the person next to them stepped out first. Dr Faria said that men tended to follow their neighbours more often than women waiting to cross the road.

"It could be that men are more likely to take the risk of following someone across the road and women are more conscious of their surroundings," said Dr Faria, whose research has been published in the journal Behavioural Ecology and PlanetEarth Online.

Herding behaviour is common in the natural world. Wildebeests tend to wait nervously at the edge of rivers waiting for one to cross first before they all follow in a bid to avoid being attacked by crocodiles waiting in the water.

Shoals of fish also stick together in an attempt to reduce the chance of being eat and penguins wait at the edge of an ice flow for a brave individual to dive into the water first before the rest follow in a bid to avoid waiting leopard seals.

Lemmings migrate in large numbers and often follow each other into fast flowing lakes and rivers where they can drown.

Dr Faria added: "The behaviour we were seeing was much like swallows sitting on a line or penguins at an ice flow, where they are thinking about what they want to do while also watching those around them and trying to work out the optimal strategy."

He said he hoped his research might help to make people think twice before stepping out into the road. Around 13,000 pedestrians are injured each year crossing the road in the UK.

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Friday, December 10, 2010

Science fiction that turned into fact

The Personnel Halting and Stimulation Response (PHASR) gun is under development at the US Air Force Research Laboratory which like its science fiction counterpart can "stun" assailants. The real PHASR is a non-lethal, portable deterrent weapon which uses a laser system to blind the enemy temporarily.

Like their Star Trek equivalent modern mobile phones often have flip top lids and can - thanks to satellite navigation technology - be used to pinpoint your position. Unfortunately using them to "beam you up" remains a scientific dream.

The Universal Translator

Like the Star Trek device which translates alien languages, the US military is using the Phraselator in Iraq for speech translation. The website Google, among others, can translate web sites and phone manufacturer NEC is launching the first mobile phone with speech translation.

Medical Tricorder

MRI and CAT scans can like Dr McCoy's hand-held tricorder device diagnose diseases by scanning the body. The team at Yale University claim the portable biomarker detector will be able to identify signs of illness from a sample of blood within 20 minutes.

Tractor Beam

Optical tweezers are a scientific instrument that uses a focused laser beam to provide an attractive or repulsive force. Unfortunately unlike the Enterprises tractor beam which can trap and pull in space ships they only work on a microscopic level.

Cloaking device

Scientists in the real world have come up with all sorts of devices to copy the technology that renders Harry Potter and Klingon ships invisible, from "stealth" radar-absorbing dark paint to active camouflage. In the long run they are looking at a special "meta" materials, that theoretically could make light curve around an object and so make it appear as if it were not there at all.

3D holograms

Ever since Princess Leia used a hologram of herself to ask Obi Wan Kenobi for help in the film Star Wars, scientists have been trying to harness the same technology for real. Now a team led by Professor Nasser Peyghambarian, of Arizona University, have developed a way of updating the image every two seconds – making it close to "real time". The ability to beam a moving hologram to anywhere in the world could lead to holographic teleconferences, 3D adverts, and a wealth of telemedicine, engineering and entertainment industry applications.

View the original article here

Thursday, December 9, 2010

Scientists dig below Dead Sea to probe Earth's history

The project aims to examine the layers of sediment left behind beneath the lowest place on Earth over the course of millions of years, providing clues about shifting weather patterns, seismic activity and climate change.

"The sediments ... provide an 'archive' on the environmental conditions that existed in the area in its geological past," the Israel Academy of Sciences and Humanities, a partner in the project, said on Wednesday.

The thin slice of Earth's history will be extracted via a 1,200-metre (3,937-foot) deep borehole being drilled by a special rig that has been set up in the northern basin of the Dead Sea.

Once extracted, the layer-cake of soil will be subjected to high-resolution examination by scientists from fields ranging from climate science to chemistry for clues about Earth's changing environment.

Details about severe weather or major seismic activity could even provide insight into human migration in and out of the region.

"We believe that the results of this project will have vast implications in the fields of science and environment and will shed light on new natural resources," Zvi Ben-Avraham, a professor at Tel Aviv University, and Moti Stein, with the Israel Geological Survey, said in a joint statement.

"In addition, a historic hydrogeological-environmental study of the Dead Sea will help unravel the mystery of human cultural evolution in this area," they added.

The project is being sponsored by the International Continental Drilling Programme, a group that has carried out similar probes deep into the Earth's crust at locations around the world.

In an unusual example of regional co-ordination, the governments of Israel and Jordan, which lies on the east bank of the Dead Sea, as well as the Palestinian Authority are co-operating with the project, which is expected to run until the end of this year.

View the original article here

Wednesday, December 8, 2010

Star Trek-style cloaking device comes a step nearer

The device sounds like the stuff of fantasy, but scientists at Imperial College London have proved it could work in theory – at least in terms of very short bursts of time.

As well as being a sci-fi fan's dream, they believe the idea could also be used to make faster and more powerful computers.

Professor Martin McCall, the lead scientist, said that the technique worked by dividing up rays of light that are heading towards the eye.

By speeding up the front part of the ray and then slowing down the rear, you can create a gap which could be filled with an event or action.

Then by reversing the speeds the gap could be closed again before the light reaches the observer making it look nothing has happened.

At the moment it should be possible to cut two thousandth of a millionth of second from time but in future seconds or even minutes could be cut.

"Imagine a camera that is on a time delay watching a safe," said Prof McCall. "If a thief opens the safe, steals the money and locks it again in between the pictures being taken it will appear as if nothing has happened.

"We have shown that by manipulating the way the light illuminating an event reaches the viewer, it is possible to hide the passage of time in the same way.

"If you had someone moving along the corridor, it would appear to a distant observer as if they had relocated instantaneously, creating the illusion of a Star Trek transporter.

"So, theoretically, this person might be able to do something and you wouldn't notice."

In previous experiments to create "invisibility cloaks" scientists have shown that light can be curled around objects to make them seem invisible.

The teleporters used in Star Trek are said to have been based on the idea of "quantum entanglement" in an object or person is broken down into photons of light or atoms, transported and then re-materialised in a different place.

This new technology would not actually transport anyone just hide their journey.

Researcher Alberto Favaro said: "It is unlike ordinary cloaking devices because it does not attempt to divert light around an object.

"Imagine computer data moving down a channel to be like a highway full of cars.

"You want to have a pedestrian crossing without interrupting the traffic, so you slow down the cars that haven't reached the crossing, while the cars that are at or beyond the crossing get sped up, which creates a gap in the middle for the pedestrian to cross.

"Meanwhile an observer down the road would only see a steady stream of traffic."

In order to create a gap of time of about two thousandth of a millionth of a second researchers reckon they need almost two miles of fibre optic cable wrapped around a spool.

With current technology to hide a second of time would require more than 200 million miles but eventually if light could be slowed down then longer periods could be possible.

The research is outlined in the Institute of Physics' Journal of Optics.

View the original article here

Tuesday, December 7, 2010

The sci-fi inventions that maths predicts are possible

The eminent physicist Prof Amos Ori, of the Technion-Israel Institute of Technology, has set out a theoretical model of a time machine which would allow people to travel back in time to explore the past. The way the machine would work rests on Einstein’s theory of general relativity, a theory of gravity that shows how time can be warped by the gravitational pull of objects. Bend time enough and you can create a loop and the possibility of temporal travel. Prof Ori’s theory, set out in the prestigious science journal Physical Review, rests on a set of mathematical equations describing hypothetical conditions that, if established, could lead to the formation of a time machine, technically known as “closed time-like curves.” In the blends of space and time, or spacetime, in his equations, time would be able to curve back on itself, so that a person travelling around the loop might be able to go further back in time with each lap.

A rippling magic carpet that can fly through the air is a theoretical possibility, according to a Professor Lakshminarayanan Mahadevan of Harvard University. Fictional flying carpets are ubiquitous and have appeared in literature since ancient times. Now they have caught the attention of a leading mathematician. Although he has only succeeded in showing that flying is practical for a bank note sized carpet, Prof Mahadevan, and his co-workers believe that one capable of ferrying a person is far from being a pantomime fantasy. His claims were published in the journal Physical Review Letters. The key to levitating a carpet is to create uplift by making ripples that push against air close to a horizontal surface, such as a floor. The undulating movements create a high pressure in the gap between the carpet and the floor, "roughly balancing its weight." The magical part comes from the discovery that, as well as lifting it, the ripples can drive the carpet forward - a handy trick for a panto - because they make the carpet tilt slightly, moving towards the raised edge.

Warp speed

Two physicists have devised a scheme to travel faster than the speed of light. The advance could mean that Star Trek fantasies of interstellar civilisations and voyages powered by warp drive are now no longer the exclusive domain of science fiction writers. Dr Gerald Cleaver, associate professor of physics at Baylor, and Richard Obousy have come up with a new twist on an existing idea to produce a warp drive that they believe can travel faster than the speed of light, without breaking the laws of physics. In their scheme, in the Journal of the British Interplanetary Society, a starship could "warp" space so that it shrinks ahead of the vessel and expands behind it. By pushing the departure point many light years backwards while simultaneously bringing distant stars and other destinations closer, the warp drive effectively transports the starship from place to place at faster-than-light speeds. All this extraordinary feat requires, says the new study, is for scientists to harness a mysterious and poorly understood cosmic antigravity force, called dark energy. Dark energy is thought responsible for speeding up the expansion rate of our universe as time moves on, just like it did after the Big Bang, when the universe expanded much faster than the speed of light for a very brief time. This may come as a surprise since, according to relativity theory, matter cannot move through space faster than the speed of light, which is almost 300,000,000 metres per second. But that theory applies only to unwarped 'flat' space.


Professor Ulf Leonhardt and Dr Thomas Philbin, from the University of St Andrews in Scotland, have worked out a way of reversing a pheneomenon known as the Casimir force, a force of nature which normally causes objects to stick together.Their discovery could ultimately lead to frictionless micro-machines with moving parts that levitate. But they say that, in principle at least, the same effect could be used to levitate bigger objects too, even a person. The Casimir force is a consequence of quantum mechanics, the theory that describes the world of atoms and subatomic particles that is not only the most successful theory of physics but also the most baffling. The force is due to neither electrical charge or gravity, for example, but the fluctuations in all-pervasive energy fields in the intervening empty space between the objects and is one reason atoms stick together, also explaining a “dry glue” effect that enables a gecko to walk across a ceiling. Now, using a special lens of a kind that has already been built, Prof Ulf Leonhardt and Dr Thomas Philbin report in the New Journal of Physics they can engineer the Casimir force to repel, rather than attact.

View the original article here

Monday, December 6, 2010

'Youngest black hole' discovered by Nasa

Evidence of the black hole was detected by space telescopes just 30 years after it was created by a supernova, or an exploding star.

The blast took place in 1979 in the relatively nearby M100 galaxy some 50 million miles from Earth.

For a brief time the supernova, discovered by an amateur stargazer and labelled SN 1979C, looked brighter than all the billions of other stars in the same galaxy put together.

Later, a bright source of X-rays was detected from the same spot by three telescopes in space – Nasa's Chandra, Europe's XMM-Newton and Germany's ROSAT.

The X-ray radiation remained strong between 1995 and 2007. It is thought to have been produced by a new black hole consuming material pouring into it.

Astronomers believe that the black hole formed when a star about 20 times larger than the sun exploded and its core collapsed in on itself.

It became an invisible galactic plughole so powerful that even light cannot escape its gravitational pull, experts believe.

Nasa's Daniel Patnaude, of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, who led the research, said: "If our interpretation is correct, this is the nearest example where the birth of a black hole has been observed."

Though a black hole is the favoured explanation, the scientists point out that the X-ray emission could be produced by a young, rapidly spinning neutron star with a powerful wind of high energy particles.

View the original article here