Reduced air pressure and oxygen levels on planes do not raise the risk of blood clots. (Courtesy: Nature)

A study of the effects of low oxygen levels on ’economy class syndrome’ has re-opened the debate over how long-haul flights increase passengers’ risks of deep vein thrombosis (DVT), the formation of potentially fatal blood clots.
As nature.com reports, although it is well known that restricting blood flow by sitting immobile for long periods can increase the risk of such clots, some researchers have proposed that there may be other factors on flights that contribute to the risk.
Studies comparing people on long-haul flights to those sitting still on the ground have indicated that there is a difference between the two groups, although it isn’t clear exactly why. Researchers have suggested that the explanation could lie with passenger stress, poor air quality, low humidity, low air pressure, or exposure to cosmic radiation.
William Toff, from the University of Leicester, UK, decided to follow up on the notion that low air pressure, and thus low levels of oxygen, might be to blame. But after subjecting volunteers to low pressures, his team found no evidence that this had an impact on their risk of clotting.
More than 70 healthy volunteers participated in Toff’s study, each spending two eight-hour sessions in a pressure chamber. One session was at the normal air pressure of ground level, while the other was at low air pressure conditions equivalent to that at an altitude of 2,438 meters, which Toff says is the lowest pressure allowed in cabins under international flight regulations.
“This cabin pressure represents the worst case scenario to which passengers might be exposed,“ says Toff, adding that most long-haul jetliners at cruising level typically maintain cabin pressure at an altitude equivalent of 1,524 to 2,134 meters.
Blood was drawn from the volunteers before and after each of the two sessions to test four markers of the early signs of blood clotting. The researchers found no significant difference between the two groups. Toff says he thinks the prime cause of DVT in long-distance travel by air, rail or car is simply “prolonged, seated immobility“.

Gamers now have the perfect excuse to sit in front of their computers all day Ð they can perform a public service. According to the New Scientist, researchers at Carnegie Mellon University (CMU) in Pittsburgh, Pennsylvania, have designed an online game that aims to harness players’ brainpower to help make websites more accessible to blind people.
Visually impaired people often use text-to-speech converters called screen readers to listen to the content of web pages spoken by a synthesized voice. However, the pictures on most websites remain inaccessible because very few have detailed captions to accurately describe them.
The online game “Phetch“, which will be made available at http://www.peekaboom.org/phetch/, is designed to encourage other web users to generate these missing captions. Played in groups of three to five people, it randomly assigns the role of “describer“ to one player; the rest become “seekers“.
The game then serves up a randomly chosen website image to the describer, who has to write a pithy short paragraph about it. The words are then sent to the seekers, who use search engines to hunt down the correct picture on the web. The first seeker to find the image becomes the describer in the next round.
If the describer’s description is good enough to lead the seekers to the picture, it is stored as a caption for that image. If not, the attempt is discarded.

Tiny bubbles may deliver genes to help fight diabetes, American researchers say. Their experiments in rats have shown that this method can deliver insulin genes specifically to the pancreas, where insulin is needed.
According to sciencemag.com, the team injected microscopic spherical shells into rodents, and using a directed ultrasonic pulse they caused the bubbles to break and release their genetic contents in the target organ.
Paul Grayburn of Baylor University Medical Center in Texas, US, and his colleagues explored the use of microscopic bubbles, burst with a targeted pulse, to deliver insulin genes specifically to the pancreas. They injected the bubbles, which had a shell made of water-insoluble molecules, into rats. In initial experiments, the bubbles contained a plasmid Ð a piece of circular DNA Ð which only coded for a florescent protein marker.
Researchers directed an ultrasonic pulse at the pancreas of the rats to burst the tiny bubbles, releasing the genetic contents. When they later dissected the rats and examined their organs, they found there were higher levels of fluorescence in pancreatic tissue than in other tissues.
In the second part of the experiment, the bubbles contained plasmids with the human gene for insulin. The ultrasonic pulse was similarly directed towards each rat’s pancreas, and researchers later found significantly elevated levels of human insulin in the rodents.

Five steps from the Big Bang to Galaxies. (Courtesy: astro.utu.fi)

According to Einstein’s general theory of relativity, the Big Bang represents The Beginning, the grand event at which not only matter but space-time itself was born. While classical theories offer no clues about existence before that moment, a research team at Penn State has used quantum gravitational calculations to find threads that lead to an earlier time, sciencedaily.com reports.
“General relativity can be used to describe the universe back to a point at which matter becomes so dense that its equations don’t hold up,“ says Abhay Ashtekar, director of the Institute for Gravitational Physics and Geometry at Penn State. “Beyond that point, we needed to apply quantum tools that were not available to Einstein.“ By combining quantum physics with general relativity, Ashtekar and his colleagues were able to develop a model that traces through the Big Bang to a shrinking universe that exhibits physics similar to ours.
In the research, the team shows that, prior to the Big Bang, there was a contracting universe with space-time geometry that otherwise is similar to that of our current expanding universe. As gravitational forces pulled this previous universe inward, it reached a point at which the quantum properties of space-time cause gravity to become repulsive, rather than attractive. “Using quantum modifications of Einstein’s cosmological equations, we have shown that in place of a classical Big Bang there is in fact a quantum Bounce,“ says Ashtekar. “We were so surprised by the finding that there is another classical, pre-Big Bang universe that we repeated the simulations with different parameter values over several months, but we found that the Big Bounce scenario is robust.“
The research team used loop quantum gravity, a leading approach to the problem of the unification of general relativity with quantum physics. In this theory, space-time geometry itself has a discrete ’atomic’ structure and the familiar continuum is only an approximation. The fabric of space is literally woven by one-dimensional quantum threads. Near the Big-Bang, this fabric is violently torn and the quantum nature of geometry becomes important. It makes gravity strongly repulsive, giving rise to the Big Bounce.

Moderate stress during pregnancy does not harm the unborn child but can instead aid its later advancement, US research suggests.
The team asked 137 healthy women with low-risk, normal pregnancies to report on their stress between the 24th and 32nd week of pregnancy. The study in Child Development found the children of those who reported more stress were more advanced at age two.
Professor DiPietr and the researchers at John Hopkins Bloomberg School of Public Health in Baltimore expected to find that distress during pregnancy would be linked to bad behavior and temperamental dysfunction in children at age two.
Research author development psychologist Professor Janet DiPietro told BBC, “We thought maybe they would show some signs of being difficult or of emotional dysfunction. Instead we found the reverse was true.“
There were two possible explanations for this, she said. Women who have high stress levels would be generating more of the stress hormone cortisol. It is one of the chemicals produced naturally in the body when stress triggers a ’fight or flight’ response.
“Cortisol has a bad rap as the stress hormone - but every organ in the body needs cortisol to develop properly. It could be enhancing the development of organs before birth,“ said Professor DiPietro. “Alternatively, it could be that the type of women they are affects the way they bring up their child. Maybe these women have higher stress levels because they challenge themselves, and because they challenge themselves they challenge their children after birth too prompting faster development.“

A plane with no wires or mechanical connections between its engine, navigation system and onboard computers Ð only a wireless network Ð has been built and flown by engineers in Portugal.
The 3-metre-long uncrewed plane “AIVA“ relies entirely upon a Bluetooth wireless network to relay messages back and forth between critical systems Ð a technique dubbed “fly-by-wireless“.
Tests flights carried out in Portugal have shown that the system works well. Cristina Santos, at Minho University in Portugal, who developed the plane, told the New Scientist that the aim is primarily to reduce weight and power requirements. Many modern planes already use electronic wires, instead of the mechanical links and cables found in older planes, to connect components. This is a lighter and more compact way to control these systems. Some planes, such as the Boeing 777 even use optical fibers, which can carry multiple signals through a single cable.
Replacing wires with wireless radio links is a logical next step says Peter Mellor from the Centre for Software Reliability at City University in London, UK, who was not involved with the project. But he adds that it raises completely new safety issues.
Such wireless links could be susceptible to electromagnetic interference or even jamming, Mellor suggests. And it could be more difficult to build in back-up wireless connections, he says. “If you jam one link you would jam both,“ he warns.
But Santos and colleagues are working on this. She says Bluetooth is already fairly resistant to disruption as it is designed to guarantee a certain minimum data stream will always get through. “It has mechanisms for dealing with interference,“ she says.

In an important new paper forthcoming in the June issue of The Quarterly Review of Biology, Robert Shapiro argues against the widely held theory that the origin of life began with the spontaneous appearance of a large, replicating molecule such as RNA. Instead, Shapiro raises an alternative that does not depend on a “stupendously improbable accident,“ presenting the more plausible idea that life began within a mixture of simple organic molecules, multiplied through catalyzed reaction cycles and an external source of available energy.
“The diversity of organic chemistry, with its harvest of competing, interconnected reactions, becomes an asset rather than a liability in the case of the energy-driven system,“ Shapiro told sciencedaily.com. “The existence of side reaction paths can provide the network with the capacity of reacting to circumstances.“
Shapiro outlines how replicator theories, though they have been supported by “prebiotic“ syntheses carried out by chemists using modern apparatus and purified reagents, are highly unlikely. The creation of a molecule that can self-replicate requires the combination of diverse chemicals in a long sequence of reactions in a specific order, interspersed by complicated separations, purifications, and changes in locale.
Instead, Shapiro introduces the idea of a “driver“ reaction, linked to a free energy source, that helps convert an unorganized mixture into an organized, self-regulated metabolic network.
“If we wish a more plausible origin of life, then we must work with the assumption that life began, somehow, among one of the mixtures of simple organic molecules that are produced by abiotic processes,“ writes Shapiro. “Nature will be instructing us, rather than we attempting to impose our schemes onto it.“

Failed NASA mission, in which a spacecraft crashed into a satellite instead of autonomously docking with it, suffered serious problems with its navigation systems, according to a summary report on the official investigation published in space.com.
The $110 million DART mission Ð Demonstration of Autonomous Rendezvous Technology Ð went awry in April 2005. At the time of the crash, reads the report: “DART was flying toward [the satellite] at 1.5 meters per second while its navigational system thought it was 130 meters away and retreating at 0.3 meters per second.“
The summary report Ð which will not be released in full due to the sensitivity of its contents Ð cites a lack of engineering experience and lack of consultation with advisors, pressure to meet deadlines and a failure to adequately test all technical decisions as key factors in the failure.
The spacecraft was originally envisioned as a low-cost, high-risk project to test the ability of two spacecraft to maneuver in close proximity without human guidance.
As it turned out, DART managed to fulfill only 11 of its 27 mission objectives and none of its “critical technology objectives“ before prematurely placing itself in a retirement orbit. This happened 11 hours into its planned 24-hour mission.
But not everything went badly for the DART team. Launch from Vandenberg Air Force Base went smoothly, as did the early orbit and the initial lining up with its satellite rendezvous target, called MUBLCOM.