Saturday, November 13, 2010

'WIRELESS' HUMANS COULD FORM BACKBONE OF NEW MOBILE NETWORKS

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Members of the public could form the backbone of powerful new mobile internet networks by carrying wearable sensors.

According to researchers from Queen's University Belfast, the novel sensors could create new ultra high bandwidth mobile internet infrastructures and reduce the density of mobile phone base stations.

The engineers from Queen's renowned Institute of Electronics, Communications and Information Technology (ECIT), are working on a new project based on the rapidly developing science of body centric communications.

Social benefits from the work could include vast improvements in mobile gaming and remote healthcare, along with new precision monitoring of athletes and real-time tactical training in team sports.

The researchers at ECIT are investigating how small sensors carried by members of the public, in items such as next generation smartphones, could communicate with each other to create potentially vast body-to-body networks (BBNs).

The new sensors would interact to transmit data, providing 'anytime, anywhere' mobile network connectivity.

Dr Simon Cotton, from ECIT's wireless communications research group said: "In the past few years a significant amount of research has been undertaken into antennas and systems designed to share information across the surface of the human body. Until now, however, little work has been done to address the next major challenge which is one of the last frontiers in wireless communication – how that information can be transferred efficiently to an off-body location.

"The availability of body-to-body networks could bring great social benefits, including significant healthcare improvements through the use of bodyworn sensors for the widespread, routine monitoring and treatment of illness away from medical centres. This could greatly reduce the current strain on health budgets and help make the Government's vision of healthcare at home for the elderly a reality.

"If the idea takes off, BBNs could also lead to a reduction in the number of base stations needed to service mobile phone users, particularly in areas of high population density. This could help to alleviate public perceptions of adverse health associated with current networks and be more environmentally friendly due to the much lower power levels required for operation."

Dr Cotton has been awarded a prestigious joint five-year Research Fellowship by the Royal Academy of Engineering and the Engineering and Physical Research Council (EPSRC) to examine how the new technology can be harnessed to become part of everyday life.

He added: "Our work at Queen's involves collaborating with national and international academic, industrial and institutional experts to develop a range of models for wireless channels required for body centric communications. These will provide a basis for the development of the antennas, wireless devices and networking standards required to make BBNs a reality.

"Success in this field will not only bring major social benefits it could also bring significant commercial rewards for those involved. Even though the market for wearable wireless sensors is still in its infancy, it is expected to grow to more than 400 million devices annually by 2014."

(Photo: Queen’s U.B.)

Queen's University Belfast

RAISING GIANT INSECTS TO UNRAVEL ANCIENT OXYGEN

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The giant dragonflies of ancient Earth with wingspans of up to 70 centimeters (28 inches) are generally attributed to higher oxygen atmospheric levels in the atmosphere in the past. New experiments in raising modern insects in various oxygen-enriched atmospheres have confirmed that dragonflies grow bigger with more oxygen, or hyperoxia.

However, not all insects were larger when oxygen was higher in the past. For instance, the largest cockroaches ever are skittering around today. The question becomes how and why do different groups respond to changes in atmospheric oxygen.

The secrets to why these changes happened may be in the hollow tracheal tubes insects use to breathe. Getting a better handle on those changes in modern insects could make it possible to use fossilized insects as proxies for ancient oxygen levels.

“Our main interest is in how paleo-oxygen levels would have influenced the evolution of insects,” said John VandenBrooks of Arizona State University in Tempe. To do that they decided to look at the plasticity of modern insects raised in different oxygen concentrations. The team raised cockroaches, dragonflies, grasshoppers, meal worms, beetles and other insects in atmospheres containing different amounts of oxygen to see if there were any effects.

One result was that dragonflies grew faster into bigger adults in hyperoxia. However, cockroaches grew slower and did not become larger adults. In all, ten out of twelve kinds of insects studied decreased in size in lower oxygen atmospheres. But there were varied responses when they were placed into an enriched oxygen atmosphere.

“The dragonflies were the most challenging of the insects to raise,” said VandenBrooks because, among other things, there is no such thing as dragonfly chow. As juveniles they need to hunt live prey and in fact undergraduate students Elyse Muñoz and Michael Weed working with Dr. VandenBrooks had to resort to hand feeding the dragonflies daily.

“Dragonflies are notoriously difficult to rear,” said VandenBrooks. “We are one of the only groups to successfully rear them to adulthood under laboratory conditions.”

Once they had worked that out, however, they raised three sets of 75 dragonflies in atmospheres containing 12 percent (the lowest oxygen has been in the past), 21 percent (like modern Earth's atmosphere) and 31 percent oxygen (the highest oxygen has been).

Cockroaches, as anyone who has fought them at home knows, are much easier to rear. That enabled the researchers to raise seven groups of 100 roaches in seven different atmospheres ranging from 12 percent to 40 percent oxygen mimicking the range of paleo-oxygen levels. Cockroaches took about twice as long to develop in high oxygen levels.

“It is the exact opposite of what we expected,” said VandenBrooks. One possibility is that the hyperoxic reared roaches stayed in their larval stage longer, perhaps waiting for their environment to change to a lower, maybe less stressful oxygen level.

This surprising result prompted the researchers to take a closer look at the breathing apparatus of roaches – their tracheal tubes. These are essentially hollow tubes in an insect's body that allow gaseous oxygen to enter directly into the insect tissues.
VandenBrooks and his team took their hyperoxic reared roaches to Argonne National Lab's x-ray synchrontron imaging facility to get a closer look at the tracheal tubes. The x-ray synchrontron is particularly good at resolving the edges where things of different phases meet – like solids on liquids or gas on solids. That's just what the inside of a tracheal tube is.

What they found was that the tracheal tubes of hyperoxic reared roaches were smaller than those in lower oxygen atmospheres. That decrease in tube size with no increase in the overall body size would allow the roaches to possibly invest more in tissues used for other vital functions other than breathing – like eating or reproducing. The roaches reared in hypoxia (lower oxygen) would have to trade off their investment in these other tissues in order to breathe.

The next step, said VandenBrooks, will be to look closely at the tracheal tubes of insects fossilized in amber to see what they might say about oxygen levels at various times in the past. These might possibly serve as a proxy for paleo-oxygen levels.

“There have been a lot of hypotheses about the impact of oxygen on evolution of animals, but nobody has really tested them,” said VandenBrooks. “So we have used a two-pronged approach: 1) study modern insects in varying oxygen levels and 2) study fossil insects and understand changes in the past in light of these results.”

The Geological Society of America

MARS VOLCANIC DEPOSIT TELLS OF WARM AND WET ENVIRONMENT

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A team led by planetary geologists at Brown University has discovered mounds of a mineral deposited on a volcanic cone less than 3.5 billion years ago that speak of a warm and wet past and may preserve evidence of one of the most recent habitable microenvironments on Mars.

Observations by NASA's Mars Reconnaissance Orbiter enabled researchers to identify the mineral as hydrated silica, a dead ringer that water was present at some time. That fact and the mounds' location on the flanks of a volcanic cone provide the best evidence yet found on Mars for an intact deposit from a hydrothermal environment — a steam fumarole or a hot spring. Such environments may have provided habitats for some of Earth's earliest life forms.

"The heat and water required to create this deposit probably made this a habitable zone," said J.R. Skok, a graduate student at Brown and lead author of the paper in Nature Geoscience. "If life did exist there, this would be a promising spot where it would have been entombed — a microbial mortuary, so to speak."

No studies have determined whether Mars has ever supported life, but this finding adds to accumulating evidence that at some times and in some places, Mars hosted favorable environments for microbial life. The deposit is located in the sprawling, flat volcanic zone known as Syrtis Major and was believed to have been left during the early Hesperian period, when most of Mars was already turning chilly and arid.

"Mars is just drying out," Skok said, "and this is one last hospitable spot in a cooling, drying Mars."

Concentrations of hydrated silica have been identified on Mars previously, including a nearly pure patch found by NASA's Mars Exploration Rover Spirit in 2007. However, this is the first found in an intact setting that clearly signals the mineral's origin.

"You have spectacular context for this deposit," Skok said. "It's right on the flank of a volcano. The setting remains essentially the same as it was when the silica was deposited."

The small, degraded cone rises about 100 meters from the floor of a shallow bowl named Nili Patera. The patera spans about 50 kilometers (30 miles) in Syrtis Major of equatorial Mars. Before the cone formed, free-flowing lava blanketed nearby plains. The collapse of an underground magma chamber from which lava had emanated created the bowl. Subsequent lava flows, still with a runny texture, coated the floor of Nili Patera. The cone grew from even later flows, apparently after evolution of the underground magma had thickened its texture so that the erupted lava would mound up.

"We can read a series of chapters in this history book and know that the cone grew from the last gasp of a giant volcanic system," said John "Jack" Mustard, professor of geological sciences and a co-author of the paper, who is Skok's thesis adviser at Brown. "The cooling and solidification of most of the magma concentrated its silica and water content."

Observations by cameras on the Mars Reconnaissance Orbiter revealed patches of bright deposits near the summit of the cone, fanning down its flank, and on flatter ground in the vicinity. The Brown researchers partnered with Scott Murchie of Johns Hopkins University Applied Physics Laboratory to analyze the bright exposures with the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) instrument on the orbiter.

Silica can be dissolved, transported and concentrated by hot water or steam. Hydrated silica identified by the spectrometer in uphill locations — confirmed by stereo imaging — indicates that hot springs or fumaroles fed by underground heating created these deposits. Silica deposits around hydrothermal vents in Iceland are among the best parallels on Earth.

"The habitable zone would have been within and alongside the conduits carrying the heated water," Murchie said.

(Photo: J.R. Skok / Brown University)

Brown University

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