Science & TechnologyS


Beaker

African gene study shows human skin tone has varied for 900,000 years

Colin Barras
New Science
Thu, 12 Oct 2017 20:38 UTC
genetic variations skin color
© Courtesy of the Tishkoff labResearcher in the field measures skin colour
Skin tone has varied greatly among humans for at least the last 900,000 years. So concludes an analysis of the genetic variants associated with skin pigmentation in people from several regions of Africa. The latest findings suggest that some particularly dark skin tones evolved relatively recently from paler genetic variants, underlining how deeply flawed the racist concept of people with whiter skin being "more advanced" really is.

Nicholas Crawford and Sarah Tishkoff at the University of Pennsylvania in Philadelphia recruited around 1500 ethnically and genetically diverse volunteers living in Ethiopia, Tanzania and Botswana for their study. Each person agreed to provide a DNA sample and have their skin pigmentation measured (pictured above).

The combined data allowed the team to find eight sites in the human genome that are particularly associated with the level of skin pigmentation. Together, these sites account for about 30 per cent of the variation they found in skin pigmentation among the volunteers.

For each of the eight sites of variation, there existed a genetic variant associated with paler skin, and a variant linked to darker skin. Seven of the paler skin variants emerged at least 270,000 years ago. Four of these arose more than 900,000 years ago.
Read More...
Footprints

Recent study suggests drought and cold climate prompted ancient humans' move out of Africa

Lakshmi Supriya
New Scientist
Mon, 09 Oct 2017 00:00 UTC
drought cold climate african migration
© Getty
Ancient humans may have trekked out of Africa to escape arid climes. This is the result suggested by a record of climate in East Africa spanning the past 200,000 years.

"It raises the possibility that drought, rather than rainy conditions, prompted early humans to migrate," says lead author Jessica Tierney at the University of Arizona.

Modern humans are widely agreed to have evolved in Africa and are thought to have migrated out 65,000 to 55,000 years ago. They may have left via East Africa and headed to Arabia, although this isn't settled.

Previous studies showed that many parts of Africa, like the Sahara, have had many wet and dry periods. A marine core, collected from the Gulf of Aden off Africa's east coast in 1965, has sediments dating to 200,000 years ago. Analysing this allowed Tierney and her colleagues to construct an extended timeline of climate shifts in north-east Africa.
Read More...
Chalkboard

It's time to fix the fact that most scientific papers end up drawing wrong conclusions

Robert Matthews
New Scientist
Mon, 09 Oct 2017 00:00 UTC
Scientists
© SolStock/GettyCrisis? What crisis?
Research findings often crumble under the microscope. Rows over the best way to fix this must end so we can stop trust in science crumbling too

In these times of fake news, it's good to know that there's still one source we can rely on: the scientific community. Wielding rigorous standards of evidence, researchers can be counted on to give us trustworthy insights amid a sea of nonsense.

Yet this, too, is fake news. For decades, scientists have been using flawed methods for turning raw data into insight about, say, the effectiveness of a new medical therapy or method of teaching. As a result, the research literature is awash with findings that are nothing more than meaningless flukes. No less shocking is the fact that researchers have been repeatedly warned about the problem, to no effect.

This week, the American Statistical Association (ASA) hopes to change that. It is hosting a conference intended to get the scientific community to mend its ways. But what has this scientific crisis got to do with statistics?
Read More...
Galaxy

Why our 'freakish' galaxy has got cosmologists seriously rethinking what they know

Geraint Lewis
New Scientist
Thu, 19 Oct 2017 00:00 UTC
Galaxy
© ESO/S. GuisardDoes a typical galaxy even exist?
In the grand club of galaxies, the Milky Way is increasingly looking like an outlier. This is a looming challenge for cosmology

It has long been assumed that our galaxy is a classic example of many of the galaxies that pepper the cosmos. That's important, because astronomers have intensely studied the Milky Way and, with this assumption, can use what they find to inform their view of the wider universe.

But what if our neck of the woods isn't that normal after all? It would be a big deal for cosmologists and astronomers. That question is coming to the fore because yet more observations suggest that our galaxy is an "outlier" in important ways. And if it isn't a representative galaxy, a fair chunk of astronomical thinking could be out of kilter.
Read More...
Ice Cube

Greenland ice stream retreated during the Younger Dryas period

Anthony Watts
Watts Up With That?
Fri, 20 Oct 2017 17:48 UTC
ice stream
© Niels J. KorsgaardA fast-flowing ice stream at Upernavik, Northwest Greenland, terminating in Baffin Bay. The ice stream is recognizable by its heavily crevassed ice next to the smoother, slower-moving ice.
Ice stream retreats under a cold climate

Why did the Jakobshavn Isbræ ice stream in West Greenland retreat under a cold climate period called the Younger Dryas?

A research article, published in Nature Communications, shows that a warmer ocean surface in central-eastern Baffin Bay triggered the ice retreat during this cold period. The Younger Dryas period occurred 12,900-11,700 years ago and interrupted the atmospheric warming after the last ice age.
Read More...
Green Light

Stay or flee? Energy reserves influence the predator-prey relationship


Science Mag
Wed, 18 Oct 2017 15:58 UTC
lion gazelle
© Kindred
Signal Detection Theory is a popular and well-established idea that has influenced behavioral science for around 50 years. Essentially, the theory holds that in a predator-prey relationship, prey animals will show more wariness and be more prone to flee as predators become more common. Danger signals are ambiguous, so in what appears to be a threatening situation, animals are better off running than hanging around to see if a predator really does strike.

Now Pete Trimmer, a postdoctoral research at UC Davis, has taken a fresh look at signal detection theory and come up with what at first look like counterintuitive results. In many cases, he says, animals should actually become less cautious as the risk of predation rises.

The problem with conventional signal detection theory, Trimmer says, is that it only considers one decision at a time, in isolation. But in reality, animals may have to make multiple connected decisions and have to take into account the effects of decisions over time.

Trimmer, graduate student Sean Ehlman and Professor Andy Sih at UC Davis, with mathematician John McNamara at the University of Bristol, U.K. developed a new model that they call state-dependent detection theory or SDDT. The work is published Oct. 18 in the journal Proceedings of the Royal Society B.
Read More...
Mars

Is an extra world hidden on the edge of our solar system? Evidence that Planet Nine does exist amasses as experts show it could explain the strange orbits of distant rocks

Harry Pettit
Daily Mail
Thu, 19 Oct 2017 17:05 UTC
Scientists have found that the orbits of distant rocks in the solar system can be explained by the presence of a ninth planet.
Scientists have found that the orbits of distant rocks in the solar system can be explained by the presence of a ninth planet. The research follows claims from Nasa last week that imagining Planet Nine (artist's impression) does not exist generates more problems than it solves
Scientists have long debated whether or not a mysterious ninth planet lurks at the edge of our solar system.

Some astronomers think the existence of the alleged planet - which they claim is 10 times the size of Earth - explains the bizarre way some distant objects in space move.

Now scientists have found new evidence that 'Planet Nine' exists by building simulations of the solar system with different sizes of the celestial body.

They found that the unusual orbits of distant rocks in our system can be explained by the presence of a ninth planet with the dimensions scientists have proposed.

Last week, Nasa highlighted five lines of evidence pointing to the existence of the elusive world, and said that imagining Planet Nine does not exist generates more problems than it solves.

Comment: For a broader, clearer understanding about the nature this celestial body and it's associated effects, read also: Sott Exclusive: Nemesis, not 'Nibiru' - Clarifying mainstream reports about 'a large ninth planet' that periodically sends comets our way

Read More...
Satellite

US launches second classified 'spy satellite' in just three weeks

Harry Pettit
Daily Mail
Mon, 16 Oct 2017 00:00 UTC
US spy satellite launch october 2017
A spy satellite atop an Atlas V rocket blasted off on a classified mission early Sunday morning from Cape Canaveral Air Force Station in Florida
A spy satellite atop an Atlas V rocket blasted off on a classified mission early Sunday morning from Cape Canaveral Air Force Station in Florida.

US officials have not revealed what the satellite will be doing or what its orbit will be, making it the second secret spy craft launched by the country in just three weeks.

Some have suggested it will use sensors to gather data on an enemy's electronic defence network, including radars, surface-to-air missile systems and aircraft.

The satellite, which launched at 3:28am ET (7:28 BST) yesterday, had experienced a week of delays due to poor weather and a faulty transmitter that had to be replaced.
Read More...
Robot

Rise of the machines: Google's machine-learning software has learned to build its own software

Karla Lant
Futurism
Mon, 16 Oct 2017 17:18 UTC
google data storage
Back in May, Google revealed its AutoML project; artificial intelligence (AI) designed to help them create other AIs.

Now, Google has announced that AutoML has beaten the human AI engineers at their own game by building machine-learning software that's more efficient and powerful than the best human-designed systems.

An AutoML system recently broke a record for categorising images by their content, scoring 82 percent.

While that's a relatively simple task, AutoML also beat the human-built system at a more complex task integral to autonomous robots and augmented reality: marking the location of multiple objects in an image.
Read More...
Magnify

Study finds intelligent people are more at risk of mental illness

Henry Austin
The Independent
Wed, 18 Oct 2017 16:56 UTC
colors
The stereotype of a tortured genius may have a basis in reality after a new study found that people with higher IQs are more at risk of developing mental illness.

A team of US researchers surveyed 3,715 members of American Mensa with an IQ higher than 130. An "average IQ score" or "normal IQ score" can be defined as a score between 85 and 115.

The team asked the Mensa members to report whether they had been diagnoses with mental illnesses, including autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD).

They were also asked to report mood and anxiety disorders, or whether the suspected they suffered from any mental illnesses that had yet to be diagnosed, as well as physiological diseases, like food allergies and asthma.
Read More...