Excerpts from science, technology, environment and health reports from around the web.

Cicadas return: How do they know when it’s time to emerge? [http://www.csmonitor.com/Science/2013/0506/Cicadas-return-How-do-they-know-when-it-s-time-to-emerge-video?nav=127-csm_category-topStories]

Try this backyard science project: Find a tree, dig a hole near it, bury yourself underground, and wait exactly 17 years before you reemerge, surviving off the juices from your tree's roots in the meantime. You are not allowed to use any kind of clock.

Pretty difficult, wasn't it?

As everyone who lives anywhere near U.S. Interstate 95 is finding out, billions of cicadas are popping out of the ground as if on cue, seeing the sky for the first time since 1996.

First Tunguska meteorite fragments discovered [http://www.technologyreview.com/view/514511/first-tunguska-meteorite-fragments-discovered/]

The Tunguska impact event is one of the great mysteries of modern history. The basic facts are well known. On 30 June 1908, a vast and powerful explosion engulfed an isolated region of Siberia near the Podkamennaya Tunguska River.

The blast was 1000 times more powerful than the bomb dropped on Hiroshima, registered 5 on the Richter scale and is thought to have knocked down some 80 million trees over an area of 2000 square kilometres. The region is so isolated, however, that historians recorded only one death and just handful of eyewitness reports from nearby.

But the most mysterious aspect of this explosion is that it left no crater and scientists have long argued over what could have caused it.

Starving Jamestown colonists engaged in cannibalism [http://blogs.discovermagazine.com/d-brief/2013/05/01/starving-jamestown-colonists-engaged-in-cannibalism/#.UYk8WbVQFN1]

Just two years after colonists established the first permanent English settlement in the Americas at Jamestown, disaster struck. During the winter of 1609-1610, known as the “starving time,” about 80 percent of the colonists died. Accounts written at the time indicate that cannibalism was one way the survivors held on. Now, examination of remains of one young woman from the period provide the first physical evidence to confirm that some colonists ate the flesh of their deceased brethren.

The incomplete human skull and tibia were excavated at the settlement’s James Fort. Researchers determined they belonged to a girl approximately 14 years old; her cause of death was unclear.

But after she died there is strong evidence that her flesh was forcibly removed, according to analysis by Douglas Owsley at the Smithsonian’s National Museum of Natural History. Owsley and his team found four shallow chops on the forehead that they say represent a failed attempt to open the skull. The back of the head appears to then have been struck by a series of forceful blows from a small hatchet or cleaver.

Researchers develop unique method for creating uniform nanoparticles [http://phys.org/news/2013-05-unique-method-uniform-nanoparticles.html]

University of Illinois researchers have developed unique approach for the synthesis of highly uniform icosahedral nanoparticles made of platinum. Results showed that the key factors for the shape control include fast nucleation, kinetically controlled growth, and protection from oxidation by air.

"We have developed unique approach for the synthesis of highly uniform icosahedral nanoparticles made of platinum (Pt)," explained Hong Yang, a professor of chemical and biomolecular engineering at the University of Illinois at Urbana-Champaign. "This is important both in fundamental studies—nanoscience and nanotechnology—and in applied sciences such as high performance fuel cell catalysts."

Study finds no evidence for theory humans wiped out megafauna

[http://phys.org/news/2013-05-evidence-theory-humans-megafauna.html]

Most species of gigantic animals that once roamed Australia had disappeared by the time people arrived, a major review of the available evidence has concluded.

The research challenges the claim that humans were primarily responsible for the demise of the megafauna in a proposed "extinction window" between 40,000 and 50,000 years ago, and points the finger instead at climate change.

Riding a new transparency wave in science, Academia.Edu lets researchers share their raw data [http://techcrunch.com/2013/05/06/academia-edu-raw-data/]

It wasn’t until widely respected economists Carmen Reinhart and Kenneth Rogoff shared the Excel files behind their influential paper on the relationship between government debt and economic growth, that a very basic and consequential spreadsheet error was discovered.

Suddenly, a conclusion that policy makers around the world had seized on for years to justify steep spending cuts was thrown in doubt.

That’s why Richard Price, the CEO of a social network for researchers called Academia.edu, says that sharing raw research data should be expected from the start. His platform is adding a feature today that lets researchers post the data behind their work through embeddable data-sets and code on their profile pages.

Earth’s crust had a billion-year youthful rampage [http://www.newscientist.com/article/dn23492-earths-crust-had-a-billionyear-youthful-rampage.html]

Our planet has calmed down in its middle age. Earth was at its most active 1.1 billion years ago, when all the continents collided into one huge supercontinent, and has been getting calmer ever since. It's evidence that the planet has a kind of lifespan.

Earth's surface layer, the crust, is divided into tectonic plates that constantly jostle against each other. When two plates collide, they can be forced up into mountains, or one plate can slide under another and be destroyed.

This tectonic activity has been going on for at least 3 billion years, but nobody knows whether Earth has been getting more or less active over time.

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