Mostrando entradas con la etiqueta Change. Mostrar todas las entradas
Mostrando entradas con la etiqueta Change. Mostrar todas las entradas

lunes, 28 de diciembre de 2015

Cómo los lobos son capaces de cambiar el curso del río

Cuando los lobos fueron reintroducidos en el parque nacional de Yellowstone en los Estados Unidos después de haber estado ausentes casi 70 años, ocurrió una "cascada trófica". ¿Qué es una cascada trófica? ¿Cómo pueden transformar los lobos el curso de un río? George Monbiot te lo explica en este video (traducido).


La recuperación de la población de lobos en el Parque Nacional de Yellowstone, en Estados Unidos, ha favorecido a todo el ecosistema. Se demuestra así la importancia de cualquier ser vivo en la naturaleza, desde los máximos depredadores hasta los más pequeños insectos. Hay que proteger la biodiversidad en cualquier región del planeta.
Según un estudio de la Universidad Estatal de Oregon, la población de alces ha sido controlada por los lobos, lo que, a su vez, ha provocado que formaciones de árboles y arbustos en las cercanías de los ríos se hayan recuperado, ya que los alces no se han comido todos los ejemplares, arrancándolos de raíz.

Los lobos, indirectamente, han beneficiado aún más al ecosistema. Como las veredas de los ríos han mejorado, también ha mejorado el hábitat de la nutria y los peces, lo que supone más alimento para aves y osos. Han pasado quince años desde que los lobos fueron reintroducidos en el Parque de Yellowstone, después de haber desaparecido el siglo pasado. En el norte, las poblaciones de alces se han reducido de más de 15.000 en la década de los noventa del siglo pasado hasta cerca de 6.000 el pasado año 2011, según un estudio publicado en la revista Biological Conservation


En 2006, algunas especies de árboles, como los álamos, habían crecido hasta una altura suficiente a la que los alces ya no podían llegar. Los álamos estaban a salvo de los alces gracias a los lobos. De este modo, a lo largo de cuatro de los arroyos de la cuenca del río Lamar, un 20% de los brotes de álamos jóvenes sobrevivieron. 

En la naturaleza, todo ser vivo es necesario. Los ecosistemas se mantienen en equilibrio y sanos mientras la biodiversidad se conserve. Ahora, en Yellowstone, hay una centena de lobos que vigilan que el parque se mantenga bien conservado. Aunque, para ello, algún alce tenga que servir como alimento.

miércoles, 23 de septiembre de 2015

Lightning Strikes Can Change Rocks' Atomic Structure

New research suggests that rock crystals melt under the intense force and heat of lightning

Lightning strikes near the U.S. Capitol building (Tech. Sgt. Cherie A. Thurlby/U.S. Air Force)
When lightning strikes sand in the desert, it instantly melts the grains, creating complex structures that geologists call fulgurites. These structures of partially melted minerals can also be found in lightning-struck rocks. But that's just the beginning: While investigating this phenomenon on an outcropping in southern France, researchers discovered that the changes can go even further — down to the atomic level

Lightning can warp quartz crystals in rock to form distinct structures typically found in meteorites, reports Elizabeth Goldbaum for LiveScience. So-called shock lamellae are minute parallel lines that run through the quartz and indicate the rock was hit with an intense force. 

"It's like if someone pushes you, you rearrange your body to be comfortable," researcher Reto Gieré of the University of Pennsylvania says in a press statement by Katherine Unger Baillie. "The mineral does the same thing." Lightning's push, however, is equivalent to a force that's 20 million times greater than a boxer's punch, as Baillie writes.

Goldbaum reports for LiveScience:
After looking at very thin, almost transparent, slices of the fulgurites under a powerful microscope, the researchers noticed that the black fulgurite looked glossy, "almost like a ceramic glaze," Gieré said. The fulgurite was also porous, similar to foam; the researchers suspect it got that way when the sizzling lightning vaporized the rock's surface.

Chemical traces of sulfur dioxide and phosphorous pentoxide were all that remained of what the researcher believe was once lichen growing on the rock’s surface. Under the foamy, glassy fulgurite layer, shock lamellae were hidden, only visible with a transmission electron microscope. There, a thin layer of what were once quartz crystals had melted and deformed so much that the crystal structure was destroyed. The team published their findings in American Mineralogist.

Once he knew what to look for, Gieré started seeing a wet, darkened look to rocks that indicated the presence of fulgurites in many places. He suggests that hikers should stay on the lookout for such rocks — especially when trekking across exposed rocky faces or scrambling to the crowns of mountaintops. Fulgurites could warn of an area prone to lightning strikes and are a good reason to keep an eye on the clouds.

The fulgurite on this rock resembles a dark stain. Via PennNews (PennNews)
ORIGINAL: Smithsonian
By Marissa Fessenden SMITHSONIAN.COM 
AUGUST 17, 2015

Jeremy England, The Man Who May One-Up Darwin

Source: Rachel Tine for OZY
On a sunny afternoon, at a bustling cafe less than a mile from Stanford University’s Palo Alto campus and more than 5,000 miles from his home, an assistant professor from MIT is telling me about science. Very advanced science. His name is Jeremy England, and at 33, he’s already being called the next Charles Darwin.

Say what?In town to give a lecture, the Harvard grad and Rhodes scholar speaks quickly, his voice rising a few pitches in tone, his long-fingered hands making sudden jerks when he’s excited. He’s skinny, with a long face, scraggly beard and carelessly groomed mop of sandy brown hair — what you might expect from a theoretical physicist. But then there’s the street-style Adidas on his feet and the kippah atop his head. And the fact that this scientist also talks a lot about God.

Every 30 years or so we experience these gigantic steps forward. …And this might be it.
Carl Franck, a Cornell physics professor

The 101 version of his big idea is this: Under the right conditions, a random group of atoms will self-organize, unbidden, to more effectively use energy. Over time and with just the right amount of, say, sunlight, a cluster of atoms could come remarkably close to what we call life. In fact, here’s a thought: Some things we consider inanimate actually may already be “alive.” It all depends on how we define life, something England’s work might prompt us to reconsider. “People think of the origin of life as being a rare process,” says Vijay Pande, a Stanford chemistry professor. “Jeremy’s proposal makes life a consequence of physical laws, not something random.

England’s idea may sound strange, even incredible, but it’s drawn the attention of an impressive posse of high-level academics. After all, while Darwinism may explain evolution and the complex world we live in today, it doesn’t account for the onset of intelligent beings. England’s insistence on probing for the step that preceded all of our current assumptions about life is what makes him stand out, says Carl Franck, a Cornell physics professor, who’s been following England’s work closely. “Every 30 years or so we experience these gigantic steps forward,” Franck says. “We’re due for one. And this might be it.

And all from a modern Orthodox Jew with fancy sneakers.

****

Before England became a religious man — he prays three times a day — he was a scientist. From the time he could read, he devoured books on subjects from philosophy to music to fantasy. By 9 he was plowing his way through Stephen Hawking’s opus, A Brief History of Time . “He couldn’t comprehend it, but he tried really hard,” says his father, Richard England, an economics professor at the University of New Hampshire. Yes, Dad is an economics professor and Mom a public school teacher, and the couple took their two children to museums and to visit the Harvard campus, just a few hours from their small seacoast town. But the elder England contends his son’s upbringing doesn’t begin to explain his intellectual curiosity.

Or England’s long timeline of asking big questions. Over drinks some years ago, a childhood friend reminded him of a time that young Jeremy turned to him out of nowhere and reflected: “You know, Adam, if the dinosaurs can go extinct, then so can we.” England was 3 then. For his part, England says it wasn’t until he hit about 7 that he felt a sense of anxiety about “not knowing enough.” That anxiety would compel him through an almost comical list of academic bastions — Harvard, Oxford, Stanford and Princeton, and now, a 3-year-old teaching gig at MIT.

Photography by Rachel Tine and Nervous System for OZY
Still, God wasn’t a big player for England during most of his early life. While his mom is Jewish — his dad was raised Lutheran but never felt strongly about passing on his Protestant ties — there wasn’t a lot of religious talk while he was growing up. The Englands would share a festive meal for Passover and light candles for Hanukkah, but the family didn’t keep a Bible in the home. His mother, England says, was born in Poland in 1947 to a family ravaged by the Holocaust. Much of her extended family — including her grandparents — were killed by the Nazis, and in the wake of such destruction, England says, Judaism brought up negative, painful feelings for her; she distanced herself.

It seems ironic, then, that anti-Semitism would eventually push England to the faith he says his mother spurned. While studying at Oxford in the early 2000s, he faced his first anti-Israel sentiment from classmates — which got him, in expected fashion, reading books and picking people’s brains to figure out where he stood on the issue. And in 2005, he visited Israel for the first time — where he “fell in love.” Studying the Torah provided an opportunity for intellectual engagement that he says was “unlike anything I had ever experienced in terms of subtlety and grandeur of scope.

****

Back in Palo Alto, between meeting with Berkeley professors and Stanford students, England reboots his computer to show me a simulation he’s been working on, meanwhile explaining that his lab is less test tubes and white coats than blackboards and computers screens. Jet-setting across the country to talk about his theories isn’t England’s usual routine. That, he says, looks more like dirty diapers, brainstorming atop a yoga ball with his infant son, working with students and plugging data into formulas.

England didn’t begin with number-crunching, though. During his postdoc research on embryonic development, he kept coming back to the question: What qualifies something as alive or not? He later superimposed an analytical rigor to that question, publishing an equation in 2013 about how much energy is required for self-replication to take place. For England, that investigation was only the beginning. “I couldn’t stop thinking about it,” he says, his normally deep voice rising until eventually cracking. “It was so frustrating.” Over the next year, he worked on a second paper, which is under peer review now. This one took his past findings and used them to explain theoretically how, under certain physical circumstances, life could emerge from nonlife.

In the most basic terms, Darwinism and the idea of natural selection tell us that well-adapted organisms evolve in order to survive and better reproduce in their environment. England doesn’t dispute this reasoning, but he argues that it’s too vague. For instance, he says, blue whales and phytoplankton thrive in the same environmental conditions — the ocean — but they do so by vastly different means. That’s because that while they’re both made of the same basic building blocks, strings of DNA are arranged differently in each organism.

Now take England’s simulation of an opera singer who holds a crystal glass and sings at a certain pitch. Instead of shattering, England predicts that over time, the atoms will rearrange themselves to better absorb the energy the singer’s voice projects, essentially protecting the glass’s livelihood. So how’s a glass distinct from, say, a plankton-type organism that rearranges it self over several generations? Does that make glass a living organism?

These are pretty things to ponder. Unfortunately, England’s work hasn’t yet provided any answers, leaving the professor in a kind of speculative state as he doggedly tries to put numbers to it all. “He hasn’t put enough cards on the table yet,” Franck says. “He’ll need to make more testable predictions.” So it remains to be seen where England will land in the end. Other scientists have made similar claims about energy dissipation in the context of non-equilibrium thermodynamics, but none has found a definitive means for applying this science to the origin of life.

****

So what does God have to do with all this? In his quest for answers, England, of course, finds himself at the center of the classic struggle between science and spirituality. While Christianity and Darwinism are generally opposed, Judaism doesn’t take issue with the science of life. The Rabbinical Council of America even takes the stance that “evolutionary theory, properly understood, is not incompatible with belief in a Divine Creator.

For his part, England believes science can give us explanations and predictions, but it can never tell us what we should do with that information. That’s where, he says, the religious teachings come in. Indeed, the man who’s one-upping Darwin has spent the past 10 years painstakingly combing through the Torah, interpreting it word by word much the way he ponders the meaning of life. His conclusion? Common translations are lacking. Take the term “creation.” England suggests we understand it not as the literal making of the Earth but rather as giving Earth a name. All throughout the Bible, he says, there are examples of terms that could be interpreted differently from what we’ve come to accept as standard.

That even applies to some of the good book’s most famous players, like Joseph, the ancient biblical interpreter of dreams, who rose to become the most powerful man in Egypt after the pharaoh. Maybe, England suggests, he wasn’t a fortune-teller. Maybe he was a scientist.

Correction: This story has been revised to reflect the correct date that England first visited Israel.

ORIGINAL: OZY
BY MEGHAN WALSH
APR 20, 2015