Sea Turtles use the Earth’s magnetic field to orient themselves Reply

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Sea turtles are masters of navigation. It begins when hatchlings, only minutes old, find their way from the beach to the sea. Once in the water, they establish a course that will take them on an epic migration. They make this dangerous journey alone, following complex migratory pathways across huge expanses of open ocean without guidance or training.

 

Loggerhead sea turtles are among the animals that can detect the Earth’s magnetic field. Could hatchlings be using this information to maintain their course in the absence of waves?

 

To answer this question, Lohmann and his colleagues needed hatchling sea turtles, a circular pool, tiny turtle harnesses, and a device that could reverse magnetic fields. Each turtle was fitted with a nylon-Lycra harness. The harness was connected to a monofilament line that tethered the turtle to an electronic tracking system in the center of a circular pool, allowing the turtles to swim in any direction. A large coil system surrounded the pool. The researchers could turn the coil system on to reverse the direction of the magnetic field around the swimming turtles.

 

Some of the tethered turtles were allowed to swim under normal magnetic field conditions. Others swam in a reversed magnetic field, turned 180° by the coil system. Hatchlings tested in the Earth’s normal magnetic field tended to swim east to northeast, the direction they normally follow in their offshore migration. But the turtles tested in the reversed magnetic field swam in the opposite direction, indicating loggerhead hatchlings are able to detect the Earth’s magnetic field and use it to orient themselves.

See on www.psychologytoday.com

Exoplanets With The Right Ingredients For Life: Carbon Planets Turn Earth’s Chemistry on Its Head Reply

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Scientists have discovered exoplanets where carbon, relatively rare on Earth, might be as common as dirt.

 

The study of exoplanets—worlds orbiting distant stars—is still in its early days. Yet already researchers have found hundreds of worlds with no nearby analogue: giants that could steamroll Jupiter; tiny pebbles broiling under stellar furnaces; puffy oddballs with the density of peat moss. Still other exoplanets might look familiar in broad-brush, only to reveal a topsy-turvy realm where rare substances are ordinary, and vice versa.

 

Take carbon, for instance: the key constituent of organic matter accounts for some of humankind’s most precious materials, from diamonds to oil. Despite its outsize importance, carbon is uncommon—it makes up less than 0.1 percent of Earth’s bulk.

 

On other worlds, though, carbon might be as common as dirt. In fact, carbon and dirt might be one and the same. An exoplanet 40 light-years away was recently identified as a promising candidate for just such a place—where carbon dominates and where the pressures in the planet’s interior crushes vast amounts of the element into diamond.

 

The planet, known as 55 Cancri e, might have a crust of graphite several hundred kilometers thick. “As you go beneath that, you see a thick layer of diamond,” says astrophysicist Nikku Madhusudhan, a postdoctoral fellow at Yale University. The crystalline diamond could account for a third of the planet’s thickness.

 

Carbon-based worlds would owe their distinct makeup to a planet-formation process very different from our own. If the composition of the sun is any indication, the cloud of dust and gas that coalesced into the planets of our solar system ought to have contained about twice as much oxygen as carbon. Indeed, Earth’s rocks are mostly based on oxygen-rich minerals called silicates. Astronomers have determined that 55 Cancri e’s host star, however, contains slightly more carbon than oxygen, which may reflect a very different planet-forming environment. And Madhusudhan and his colleagues calculated that the planet’s bulk properties—denser than a water world but less dense than a world made of Earth-like minerals—match those predicted for a carbon planet.

See on www.scientificamerican.com

Effect of Global Warming: Plants Flower Nearly a Month Earlier Than They Did A Century Ago Reply

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Compared to extreme drought, blistering heat, massive wildfires and tropical cyclones, the latest indicator of climate change is unexpectedly attractive: early spring flowers. Unusually warm spring weather in 2010 and 2012 at a pair of notable sites in the eastern U.S. led to the earliest spring flowering times on record—earlier than any other time in the last 161 years.

 

The researchers involved, from Boston University, the University of Wisconsin and Harvard, examined the flowers at two sites well-known for their roles in the early environmental movement: Walden Pond, where Henry David Thoreau started keeping flowering records back in 1852, and Dane County, Wisc., where Aldo Leopold first recorded flowering data in 1935.

 

“We were amazed that wildflowers in Concord flowered almost a month earlier in 2012 than they did in Thoreau’s time or any other recent year, and it turns out the same phenomenon was happening in Wisconsin where Aldo Leopold was recording flowering times,” lead author Elizabeth Ellwood of Boston University said in a statement. “Our data shows that plants keep shifting their flowering times ever earlier as the climate continues to warm.”

 

In Massachusetts, the team studied 32 native spring flowering plant species—such as wild columbine, marsh marigold and pink lady slipper—for which average flowering dates had been fairly well-documented between Thoreau’s time and our own. They found that the plants’ flowering dates had steadily moved earlier as temperatures increased—Thoreau saw them flower on May 15, while they flowered on April 25 and 24 in 2010 and 2012, respectively. In the two years studied, 27 of the 32 species had their earliest flowering date ever.

See on blogs.smithsonianmag.com

Designer bacteria may lead to better vaccines Reply

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Researchers at The University of Texas at Austin have developed a menu of 61 new strains of genetically engineered bacteria that may improve the efficacy of vaccines for diseases such as flu, pertussis, cholera and HPV.

 

The strains of E. coli, which were described in a paper published this month in the journal PNAS, are part of a new class of biological “adjuvants” that is poised to transform vaccine design. Adjuvants are substances added to vaccines to boost the human immune response. “For 70 years the only adjuvants being used were aluminum salts,” said Stephen Trent, associate professor of biology in the College of Natural Sciences. “They worked, but we didn’t fully understand why, and there were limitations. Then four years ago the first biological adjuvant was approved by the Food and Drug Administration. I think what we’re doing is a step forward from that. It’s going to allow us to design vaccines in a much more intentional way.”

 

Adjuvants were discovered in the early years of commercial vaccine production, when it was noticed that batches of vaccine that were accidentally contaminated often seemed to be more effective than those that were pure. “They’re called the ‘dirty little secret’ of immunology,” said Trent. “If the vials were dirty, they elicited a better immune response.” What researchers eventually realized was that they could produce a one-two punch by intentionally adding their own dirt (adjuvant) to the mix. The main ingredient of the vaccine, which was a killed or inactivated version of the bacteria or virus that the vaccine was meant to protect against, did what it was supposed to do. It “taught” the body’s immune system to recognize it and produce antibodies in response to it. The adjuvant amplifies that response by triggering a more general alarm, which puts more agents of the immune system in circulation in the bloodstream, where they can then learn to recognize the key antigen. The result is an immune system more heavily armed to fight the virus or bacteria when it encounters it in the future.

See on phys.org

Asteroid deflection mission seeks innovative new ideas Reply

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AIDA mission concept (credit: ESA) A space rock several hundred meters across is heading towards our planet and the last-ditch attempt to avert a disaster.

 

The first Double Asteroid Redirection Test (DART) spacecraft, designed by the Johns Hopkins Applied Physics Laboratory, will collide with the smaller of the two asteroids.

 

Meanwhile, ESA’s Asteroid Impact Monitor (AIM) craft will survey these bodies in detail, before and after the collision.

 

The impact should change the pace at which the objects spin around each other, observable from Earth. But AIM’s close-up view will ‘ground-truth’ such observations.

 

“The advantage is that the spacecraft are simple and independent,” says Andy Cheng of Johns Hopkins, leading the AIDA project on the US side. “They can both complete their primary investigation without the other one.”

But by working in tandem, the quality and quantity of results will increase greatly, explains Andrés Gálvez, ESA AIDA study manager: “Both missions become better when put together — getting much more out of the overall investment.

 

“And the vast amounts of data coming from the joint mission should help to validate various theories, such as our impact modeling.”

See on www.kurzweilai.net