ريتشارد دوكنز's Blog, page 516
April 9, 2016
Rogue Exoplanet Is One Of The Youngest And Brightest Ever Discovered
Photo credit:
An artist's impression of a rogue gas giant. NASA/JPL-Caltech
A free-floating or “rogue” exoplanet has been found adrift within our solar neighborhood. Just 10 million years in age, this giant loner is essentially a baby on galactic time scales. Without a star to call its own, this makes it an orphan, too – but don’t fret, it’s only 95 light-years from Earth, so it’s not too far away from some celestial company.
Tigers Are Functionally Extinct In Cambodia
Photo credit:
Cambodia's forests of the night could soon host tigers again. Luke Wait/Shutterstock
Cambodia has launched a plan to return tigers to the country, starting by acknowledging that the apex predator is locally “functionally extinct”.
If the first stage of solving a problem is admitting you have it, Cambodia has taken its time on this one. According to conservation group WWF the last recording of a tiger in the country was in 2007, when a camera trap detected one in Mondulkiri province.
The High-Speed Strikes Of Trap-Jaw Spiders Are Power Amplified
Photo credit:
The face of a male Chilarchaea quellon trap-jaw spider. The chelicerae in front have fangs at the tip. Hannah Wood/Smithsonian
Using high-speed videos, researchers have captured trap-jaw spiders striking at their prey. Not only does this occur at lightning speed, it’s also power amplified, according to findings published in Current Biology this week.
Cloud Contributions Could Make Global Warming Even Worse
Photo credit:
Yes they look pretty, but these clouds may have a dire warning for the planet. Pakhnyushchy/Shutterstock
It has been a bad fortnight for climate change news, from the heat-induced devastation of coral reefs to warnings that sea levels could rise much faster than we thought.
Samsung Has Patented An Augmented Reality Smart-Contact Lens
Photo credit:
Alpha Zynism/Shutterstock
Google Glass perhaps didn’t receive the earth-shattering response the company – and world – had expected. However, a proposal that Samsung appears to have in the works could be the augmented reality wearable tech everybody is holding out for.
It looks like the Korean tech giant has been thinking about creating the world’s first "smart" contact lenses, able to take photographs with the blink of an eye, technology blog Sammobile reports.
April 8, 2016
What We’re Reading
Whether you find someone to read them to you (as in Rudolf Ernst’s “The Reader”) or you read them yourself, we’ve found a nice selection of articles on evolution, climate change, and the history of science for you to while away the weekend. Enjoy! And let us know of your reactions and suggestions for future weeks in the comments section below.
Pioneer, American Scientist, March–April 2016 — Laura Dassow Walls reviews Andrea Wulf's The Invention of Nature (2015), a new biography of Alexander von Humboldt, the nineteenth-century naturalist Walls describes as “a walking, talking, one-man planetary paradigm shift.”
Even in a Warming World, It Will Still Snow Somewhere, The New York Times, April 2, 2016 — The Gray Lady used the first week of April to debunk myths, and the climate change denial myth regarding the end of all snow in a warming planet unsurprisingly showed up, on day 2.
Finally, You Can See Dinosaurs in all their Feathered Glory, National Geographic, April 5, 2016 — Dinosaurs with feathers! This article describes the first major exhibit, at the American Museum of Natural History, to show dinosaurs in their currently accepted, feathery rather than scaly, guise.
Sea Levels Could Rise Twice as Fast as Previously Predicted, Science News, April 6, 2016 — “Antarctica’s meltdown could spur sea level rise well beyond current predictions. A new simulation of the continent’s thawing ice suggests that Antarctic melting alone will raise global sea levels by about 64 to 114 centimeters by 2100…”
Nearby Supernova Explosions May Have Affected Human Evolution, SPACE.com via Scientific American, April 6, 2016 — A report on two recent studies published in Nature that discerned faint evidence for the effect on Earth of supernovas occurring over three hundred light years away.
Good News on Climate Change…and Bad News, The Nation, April 7, 2016 — “Global emissions may have peaked—but temperatures are rising at record speed, threatening a massive sea-level rise that could destroy major cities by 2100,” warns Mark Hertsgaard, the author of Hot (2011).
Intelligent Design and Nylon-Eating Bacteria, BioLogos, April 7, 2016 — Dennis Venema uses nylonase—an enzyme that helps certain bacteria to digest nylon, a synthetic chemical not found in nature—to rebut “intelligent design” creationist claims about the unevolvability of proteins.
Darwin in Letters, 1871: An Emptying Nest, Darwin Correspondence Project — Now that the full texts of nearly 800 letters Darwin wrote and received during 1871 are available on-line, the Darwin Correspondence Project presents a handy overview. (Why “Emptying Nest”? His eldest daughter married in 1871.)
Here’s What Happens To Your Body When You Get Bitten By A Black Widow Spider
Photo credit:
Sari ONeal/Shutterstock
As you can probably guess by its name and the fact that they look like a supervillain's logo, black widow spider bites are no fun. These small spiders already have a notorious reputation, but do you know what actually happens if you succumb to one of their bites?
Within just 15 minutes, the spider’s cocktail of neurotoxins starts to take hold. From then on, things go from bad to worse, as this video from Tech Insider explains.
PETA Just Made A Very Bizarre Claim About What Eating Chicken Will Do To You
Photo credit:
Jacek Chabraszewski/Shutterstock
People become vegetarians for many reasons: concerns about animal welfare, concerns about the environment, and even simply concerns about their health. Well, how about anxieties about your unborn child’s penis?
That’s the message PETA posted to Facebook in a video called “Eating Chicken Can Make Your Kid's Dick Small.”
Hacking an Enzyme’s Structure Could Lead to Drugs for Alzheimer’s and Schizophrenia
The brain relies on a system of chemical messengers, known as neurotransmitters, to carry missives from cell to cell. When all is well, these communications enable the brain to coordinate various functions, from complex thought to quick, knee-jerk reactions—but when the system is out of whack, serious disease or disorder can ensue.
A team of researchers at the Technical University of Denmark (D.T.U.) and University of Oxford have for the first time identified the molecular structure of dopamine beta-hydroxylase (DBH), the enzyme that controls the conversion between dopamine and norepinephrine, two major neurotransmitters. Understanding the crystal structure of the enzyme could provide an ideal target for drug development.
Dopamine and norepinephrine play key roles in many brain functions such as learning, memory, movement and the fight-or-flight response. Imbalances in the levels of these neurotransmitters—and the role DBH plays in regulating them—have been implicated in a wide range of disorders, including hypertension, congestive heart failure, anxiety, depression, post-traumatic stress disorder, Alzheimer’s, schizophrenia, Parkinson’s and even cocaine addiction.
DBH has long intrigued biochemists but it has been challenging to perform the analyses needed to determine the protein’s structure. “This enzyme has been particularly difficult,” says Hans Christensen, a chemist at D.T.U. and the study’s lead researcher. “We tried many different expression systems before we finally succeeded. Now that we have the structure it is clear why—[it] is very intricate, with different parts of the enzyme interacting very tightly.”
Using x-ray crystallography, a technique used to determine protein structure, Christensen and his team found that DBH contains two potential binding sites: first, a pocket where another molecule can bind, common to the class of enzymes to which DBH belongs. There was, however, also a binding site for metal ions that was entirely unanticipated. “What we see in the structure of the enzyme is that it is not at all as people have been expecting,” Christensen says.
In fact, the only part of the structure that was previously known concerned the portion of the enzyme that performs catalytic reactions—and now the researchers have discovered that this region may take a second form, in which two copper-binding sites are located much closer together than predicted. “This might in fact be the active form of the enzyme,” Christensen says. “If that is the case, it [would be] easier to understand how the enzyme actually works, but a lot more research is needed to clarify this.”
Mario Amzel, a biophysicist at Johns Hopkins University who did not participate in this research but has studied the crystal structure of a related enzyme, expressed some doubt about this assumption. “In general, I don’t think that the proximity of the two copper sites will be followed up [in future research],” he says. Even so, Amzel is optimistic about the finding. “The structure is a major accomplishment,” he adds. “The molecule is much larger than the catalytic core. What’s expected is that other parts of the molecule are involved in the regulation or modulation of activity in many ways. How that activity is controlled by these other parts of the molecule is a very important direction where the field will start going.”
Knowing the structure of the enzyme could lead to the development of pharmaceuticals that target the two binding sites the researchers located. “Our next step is to link up with the biotech industry to try to help them develop drugs,” Christensen says. Previous research shows that in most cases, this will mean reducing the activity of DBH, although certain disorders may in fact require that the enzyme do more work. DBH inhibitors are already in clinical development for cocaine dependence, hypertension and PTSD—although these target only the copper-binding sites. The latest findings can facilitate more directed research toward new treatments.
Earth Is Tipping Because of Climate Change
The north pole is on the run. Although it can drift as much as 10 meters across a century, sometimes returning to near its origin, it has recently taken a sharp turn to the east. Climate change is the likely culprit, yet scientists are debating how much melting ice or changing rain patterns affect the pole’s wanderlust.
The geographical poles—the north and south tips of the axis that the Earth spins around—wobble over time due to small variations in the sun’s and moon’s pulls, and potentially to motion in Earth’s core and mantle. But changes on the planet’s surface can alter the poles, too. They wobble with every season as the distribution of snow and rain change, and over long stretches as well. Roughly 10,000 years ago, for example, Earth woke up from a deep freeze and the massive ice sheets sitting atop what is now Canada melted. As ice mass fled, and the depressed crust rebounded, the distribution of the planet’s mass changed and the north pole started to drift west. This pattern can be clearly seen in data from 1899 onward. But a recent zigzag in the north pole’s path (and the opposite movement in the south pole) suggests a new change is afoot.
Around 2000 the pole took an eastward turn; it stopped drifting toward Hudson Bay, Canada, and started drifting along the Greenwich meridian in the direction of London. In 2013Jianli Chen, a geophysicist at The University of Texas at Austin, was the first to attribute the sudden change to accelerated melting of the Greenland Ice Sheet. The result startled his team. “If you're losing enough mass to change the orientation of the Earth—that's a lot of mass,” says John Ries, Chen’s colleague at U.T. Austin. The team found that recent accelerated ice loss and associated sea level rise accounted for more than 90 percent of the latest polar shift. Of course that includes ice lost across the world, but “Greenland is the lion's share of the mass loss,” Ries says. “That's what's causing the pole to change its nature.”
Credit: NASA/JPL-Caltech
Could such a dramatic shift be so simple? In a new study published today in Science Advances, Surendra Adhikari and Erik Ivins, two geophysicists from NASA Jet Propulsion Laboratory, think another mechanism might be at play: changes in the amount of water held within the continents. Like Chen’s team, Adhikari and Ivins compared data collected by NASA’s Gravity Recovery and Climate Experiment (GRACE) satellite, which measures changes in Earth’s gravitational field, with Global Positioning System (GPS) measurements of the north and south poles. But Adhikari and Ivins have a couple extra years of data. They also incorporated small-scale features within the GRACE data set that are more directly related to terrestrial water storage.
Although the predominant cause of the pole’s shift still turned out to be Greenland, a recent dry spell that has overrun Eurasia is also driving the pole toward the east, Ivans says. With less rainfall on a continent over time, it starts to shed some bulkAdhikari and Ivins think the sudden shift could be the latest in a series of decadal changes in drift that scientists have been unable to explain. Eurasia, which was quite lush 10 years ago, is not the only continent to experience a drought. “We think this flip is happening all the time,” Ivins says. “It’s a natural phenomenon that characterizes the entire Earth rotation time-series going all the way back to 1899.”
The data do not indicate whether the recent climate changes are man-made, but Chen personally believes the drastic shift in the pole has to be the result of human activities. Meanwhile Ivins thinks he will be able to tease man-made climate change from the data in another six months or so. Given that polar motion and climate variability seem to be inextricably linked, scientists can look at historical records of the pole’s motion (which date back to well before the advent of GPS and the GRACE satellite) and see changes in Earth’s climate. If those changes are less dramatic than the ones we see today, Ivins says, then scientists could say that global warming has a controlling influence on Earth’s poles.
ريتشارد دوكنز's Blog
- ريتشارد دوكنز's profile
- 106 followers
