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Science Sunday #7

Posted by Don McLenaghen on July 31, 2011

– and on the seventh day we learn.
Each week I hope to give a synopsis of the interesting science stories I have heard on my plethora of science podcasts I listen to each week plus anything I pick up scanning the inter-web. This week’s top stories:

Words of the Week:

Lagrange Point – The five positions in an orbital configuration where a small object affected only by gravity can theoretically be stationary relative to two larger objects (such as a satellite with respect to the Earth and Moon). The Lagrange points mark positions where the combined gravitational pull of the two large masses provides precisely the centripetal force required to rotate with them..

Trojan Point – a minor planet or natural satellite (moon) that shares an orbit with a larger planet or moon, but does not collide with it because it orbits around one of the two Lagrangian points of stability (Trojan points), L4 and L5, which lie approximately 60° ahead of and behind the larger body. Trojan objects are one type of co-orbital object. Trojan asteroids are small Solar System bodies that reside in Trojan points. Trojan moons are moons that reside at Trojan points. Trojan planets are theoretical planets that reside at Trojan points. The term “Trojan” originally referred to the Trojan asteroids orbiting around Jupiter’s Lagrangian points which are by convention named after figures from the Trojan War.

Chimera fossil sheds light on origin of wings –

Dr. Arnold H. Staniczek and Dr. Günter Bechly at the Stuttgart Natural History Museum discovered a new insect order from the Lower Cretaceous of South America. The spectacular fossils were named Coxoplectoptera by their discoverers and their findings were published in a special issue on Cretaceous Insects in the scientific journal Insect Systematics & Evolution.

Equipped with wing venation of a mayfly, breast and wing shape of a dragonfly, and legs of a praying mantis, these winged insects look like a patchwork of various animals.

Their lifestyle turned out to be a major enigma: their mode of embedding and certain other characteristics clearly suggest a fluvial habitat. Their unique anatomy indicates that these animals were ambush predators living partly dug in the river bed.

These animals furthermore provided clues to the long-standing controversial debate of the evolutionary origin of the insect wing. The scientists presume that wings originated from thoracic backplates, while leg genes were recruited for their developmental control.

Scientific America

Cosmos

Science Daily

‘Fluid cloak’ to help submarines leave no wake –

SUPER-STEALTHY submarines may one day glide through the water without creating a wake, if a plan to channel fluid intelligently around objects can be made to work.

A vehicle moving through a fluid normally disturbs the medium in two ways. First, some of the fluid gets dragged along with the vehicle, sapping its energy and slowing it down. Second, a turbulent wake forms behind it where fluid rushes in to fill the vacant space. The churning fluid in the wake in turn creates noise that reveals the vehicle’s presence.

But channelling the fluid around the object in just the right way could solve both problems at once. To do this, Yaroslav Urzhumov and David Smith of Duke University in Durham, North Carolina, propose encasing it in a mesh shell.

Crucially, the permeability of this mesh casing should vary from place to place to alter the speed of fluid flowing through it. Of course, just any old mesh would not work; it has to have a specific pattern to achieve channelling. The overall effect of their pattern is to initially accelerate the incoming fluid near the front of the shell, then to let it slow back down to its original speed at the back of the shell before it exits

Since there is no net change to the motion of the fluid when the vehicle passes through it, there is no drag and no turbulent wake. The fluid closes seamlessly around the vehicle, as if it had never been there. “It’s possible to have this structure glide through the fluid without disturbing it at all,” says Urzhumov.

New Scientist

Fluid flow control with transformation media

Were the best world leaders mentally ill? – 

Was JFK a successful, drug-fuelled maniac, and Nixon a sane failure?

In A First-Rate Madness, Nassir Ghaemi argues that psychiatric disorders were the making of some of the great world leaders

It has become fashionable to talk up the positive side of mental illness, to explain the persistence of conditions such as severe depression in terms of the benefits they bring to the people who experience them. For example, the tendency of depressed people to ruminate – generally considered an undesirable trait because it fuels negative thinking – could actually deepen their understanding of their problems and enhance decision-making.

There is little empirical data to support this position at present, and its many detractors point out, for instance, that depressed people tend to ruminate in an irrational way that is unlikely to lead to enlightening insights. This has not deterred Nassir Ghaemi, a professor of psychiatry at Tufts University School of Medicine in Boston, whose latest book, A First-Rate Madness, pushes the rose-tinted view of mental illness into new territory. He argues that the best leaders during troubled times are those with mood disorders, since their illness enhances the very qualities that crisis management demands. In times of crisis, he concludes, “we are better off being led by mentally ill leaders than by mentally normal ones”.

New Scientist

Minority Rules –

Scientists Discover Tipping Point for the Spread of Ideas.

Scientists at Rensselaer Polytechnic Institute have found that when just 10 percent of the population holds an unshakable belief, their belief will always be adopted by the majority of the society. The scientists, who are members of the Social Cognitive Networks Academic Research Center (SCNARC) at Rensselaer, used computational and analytical methods to discover the tipping point where a minority belief becomes the majority opinion. The finding has implications for the study and influence of societal interactions ranging from the spread of innovations to the movement of political ideals..

“When the number of committed opinion holders is below 10 percent, there is no visible progress in the spread of ideas. It would literally take the amount of time comparable to the age of the universe for this size group to reach the majority,” said SCNARC Director Boleslaw Szymanski, the Claire and Roland Schmitt Distinguished Professor at Rensselaer. “Once that number grows above 10 percent, the idea spreads like flame.”

Rensselaer Polytechnic Institute

Science Daily

NASA and International Partners Discuss New Uses for Space Station – 

The Multilateral Coordination Board (MCB) for the International Space Station partner agencies met Tuesday, July 26, to discuss how to use the space station as a test bed for technologies that will enable missions beyond low Earth orbit.

Science Daily 

International Space Station to be ‘sunk’ after 2020 – 

Russia and its partners plan to plunge the International Space Station (ISS) into the ocean at the end of its life cycle after 2020 so as not to leave space junk, the space agency said on Wednesday.

“After it completes its existence, we will be forced to sink the ISS. It cannot be left in orbit, it’s too complex, too heavy an object, it can leave behind lots of rubbish,” said deputy head of Roskosmos space agency Vitaly Davydov.

“Right now we’ve agreed with our partners that the station will be used until approximately 2020,” he said in comments released on Wednesday.

Moscow this month proclaimed the beginning of “the era of the Soyuz” after the US shuttle’s last flight left the Russian system as the sole means for delivering astronauts to the ISS.

RawStory

Wasp Uses Ladybug as ‘Zombie Bodyguard’ – 

The parasitic wasp Dinocampus coccinellae is no fool. It controls a ladybug, lays an egg in its abdomen and turns it into the bodyguard of its cocoon.

Although this strategy enables the wasps to protect their larvae from predation, it has a cost: the wasps pay for it in terms of fertility. The researchers have also demonstrated the reversible character of this manipulation: once the larvae have hatched, some ladybugs can recover normal behavior.

Females deposit a single egg in the abdomen of their host, the ladybug, and during larval development (around twenty days) the parasite feeds on the host’s tissues. Then, the wasp larva breaks out through the ladybug’s abdomen, without killing it, and begins spinning a cocoon between the ladybug’s legs. The ladybug, partially paralyzed, is forced to stand guard over the cocoon

Science Daily

Biology Letters – The cost of a bodyguard

A Trojan Asteroid Keeps Earth Company – 

The moon isn’t the only hunk of space rock that has been travelling around the sun with the Earth for ages.

Canadian scientists have discovered that the Earth is also accompanied by a “Trojan” companion — an asteroid that travels a constant distance ahead of it at all times, sharing nearly the same orbit around the sun.

Similar objects have been found travelling with other planets in our solar system, including Mars, Jupiter and Neptune.

CBC

Science Friday

Making Connections

Gastric bypass creates a healthier appetite – 

After people undergo gastric bypass operations, it is not uncommon for them to report that their eating habits have changed. To investigate these claims, Carel le Roux and colleagues from Imperial College London asked 16 people who had undergone either type of bariatric surgery six years before to fill in a survey about their dietary preferences after the operation.

People who had had a gastric bypass reported eating a lower proportion of fat after surgery than those with a vertical-banded gastroplasty.

To find out why this was so, the team carried out either a gastric bypass or a sham operation on 26 rats.

They found the rats with the gastric bypass ate less and regained less weight after recovering from the surgery than the others.

Le Roux’s team also found that levels of hormones which promote satiety – such as glucagon-like peptide-1 (GLP-1) and peptide YY (PYY) – were higher in rats with a gastric bypass after eating than in the sham-operated rats.GLP-1 may be important when it comes to food preferences. The hormone, which promotes insulin production

New Scientist

American Physiological Society – Gastric bypass reduces fat intake and preference

 

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