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Why Neanderthals were always an endangered species

Ewen Callaway
New Scientist
Sat, 18 Jul 2009 13:11 UTC
Image
© American Museum of Natural History
Neanderthal populations were sparsely distrubuted.
For much of their 400,000 year history, Neanderthals were few and far between, a new analysis of genetic material from several of the extinct, ancient humans now suggests.

It's difficult to put a number on the population of a species based on DNA alone, but less than a few hundred thousand of the archaic humans roamed Europe and Asia at any one time, says Adrian Briggs, an evolutionary geneticist at the Max Planck Institute for Evolutionary Anthropology in Leipzig. "There never were million and millions of Neanderthals," he told New Scientist.

That conclusion isn't exactly Earth-shattering. Archaeological digs suggest that Neanderthals hardly lived in megacities, and the mitochondrial genome sequence from one individual found in Croatia also hints at low population sizes.

But the new findings represent the most detailed look at Neanderthal genetic diversity yet published.
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Sun

Mystery Source of Solar Wind Heating Identified


PhysOrg
Sat, 18 Jul 2009 11:27 UTC
Solar Wind
© NASA
The solar wind, shown here in a plot of data from the Ulysses spacecraft, flows away from the sun at a million miles per hour and is heated by a "turbulent cascade."
The solar wind is hotter than it should be, and for decades researchers have puzzled over the unknown source of energy that heats it. In a paper published in the June 12 issue of Physical Review Letters, NASA scientists say they may have found the answer.

"The energy source is turbulence," says co-author Melvyn Goldstein, chief of the Geospace Physics Laboratory at NASA's Goddard Space Flight Center, Greenbelt, Md. "The sun heats the solar wind by stirring it up."

It's a bit like stirring your coffee--in reverse. When you stir your morning cup of Joe, the coffee cools off. But when the sun stirs the solar wind, the solar wind heats up.

Consider the coffee. When you stir it with a spoon, the stirring produces swirls and vortices in the liquid. The vortices fragment into smaller and smaller eddies until, at the smallest scales, the motions dissipate and the energy turns into heat. Because energy cascades down from the large swirls to the smaller ones, the process is called a turbulent cascade.

Theoretically, the turbulent cascade should heat the coffee. Real coffee cools off, however, because the act of stirring brings warm coffee from the depths of the cup into contact with cooler air above. Cool air absorbs the heat - the heat the coffee had to begin with plus the heat you added by stirring - and you can take a sip without scalding yourself.
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Magnify

Professor Sheds Light on DNA Mechanisms


PhysOrg
Fri, 17 Jul 2009 19:24 UTC
By manipulating individual atoms in DNA and forming unique molecules, a Georgia State University researcher hopes to open new avenues in research towards better understanding the mechanisms of DNA replication and transcription, and perhaps leading to new treatments for diseases.

Chemistry and chemical biology professor Zhen Huang and his lab were able, for the first time, to manipulate methyl and phosphate groups of molecules in DNA that has been altered to contain selenium in order to bring them close enough together to form hydrogen bonds.

Such interactions may reduce the energy needed for a process called DNA duplex separation, thereby playing a role in the unwinding of DNA, which must happen in order for the genetic code to be copied and transcribed during cell replication and transcription. The research also helps to explain how energy is used in the process, Huang said.
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Light Saber

Microsoft Versus Chavez

Tamara Pearson
venezuelanalysis.com
Thu, 16 Jul 2009 21:34 UTC
Image
© Microsoft Spain
The MSN Spain home page yesterday
Yesterday, Microsoft MSN (Spain) featured a montage photo of Venezuelan president Hugo Chavez and the ex president of Cuba, Fidel Castro, wearing king's crowns, accompanied by the colourful title, "When power corrupts: Striving to be kings." The Venezuelan government and a grassroots technology movement here are both promoting the use and creation of open source (free) software, so it's no surprise that software tyrant, Microsoft, is lambasting Chavez.

Following the MSN headline was a slide show of photos of nine world leaders with paragraphs accompanying each, describing just how undemocratic and power hungry they all are. All of the leaders bar two are from Latin America or East Asia, reflecting the racist sentiment that the "West" is democratic perfection. Also, perhaps just a coincidence, East Asia and Latin America are regions with some of the strongest open source software movements.
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Sherlock

The Secret Jungles of Ancient France

Adam Dylewski
PhysOrg
Thu, 16 Jul 2009 21:17 UTC
Ah, Paris. Land of the Eiffel Tower, delicious French bread and... tropical rainforests? Sacrebleu! It seems unlikely, but scientists have discovered evidence that France may have been a hot, wet tropical rainforest 55 million years ago.

Scientists found the evidence in amber, sticky tree sap that hardens into a deep, yellow, rock-hard fossil - like the amber that scientists in Jurassic Park used to snare dino DNA. Led by Akino Jossang, the scientists studied amber found near Paris. The shocker? The type of tree that produces this amber grows today only in the Amazon rainforest!

The ancient ancestor of this tropical tree died out long ago. However, the scientists used clever detective work to find its modern plant relative. They discovered a chemical called quesnoin in their amber samples. While lots of trees produce different types of amber, only the Amazon tree produces amber containing quesnoin.
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Magnify

Male Sex Chromosome Losing Genes by Rapid Evolution, Study Reveals


PhysOrg
Fri, 17 Jul 2009 10:05 UTC
Wallaby
© Kateryna Makova, Penn State
A wallaby is a marsupial
Scientists have long suspected that the sex chromosome that only males carry is deteriorating and could disappear entirely within a few million years, but until now, no one has understood the evolutionary processes that control this chromosome's demise.

Now, a pair of Penn State scientists has discovered that this sex chromosome, the Y chromosome, has evolved at a much more rapid pace than its partner chromosome, the X chromosome, which both males and females carry. This rapid evolution of the Y chromosome has led to a dramatic loss of genes on the Y chromosome at a rate that, if maintained, eventually could lead to the Y chromosome's complete disappearance. The research team, which includes Associate Professor of Biology Kateryna Makova, the team's leader, and National Science Foundation Graduate Research Fellow Melissa Wilson, will publish its results in the 17 July 2009 issue of the journal PLoS Genetics.
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Magnify

Our Metallic Reflection: Considering Future Human-Android Interaction

Katie Kline
Association of Psychological Science
Thu, 16 Jul 2009 22:56 UTC
Everyday human interaction is not what you would call perfect, so what if there was a third party added to the mix - like a metallic version of us? In a new article in Perspectives on Psychological Science, psychologist Neal J. Roese and computer scientist Eyal Amir from the University of Illinois at Urbana-Champaign investigate what human-android interactions may be like 50 years into the future.

With knowledge of present day technology, the scientists predict that within 50 years androids will be able to speak in human-like voices, identify spoken words with precision, answer questions from a body of textual information, walk and run in a human-like motion, display realistic facial expressions, and detect others' emotions through visual processing.
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Info

New geothermal heat extraction process to deliver clean power generation

Geoffrey Harvey
Pacific Northwest National Laboratory
Thu, 16 Jul 2009 22:50 UTC
Image
© PNNL
PNNL's introduction of a metal-organic heat carrier, or MOHC, in the biphasic fluid may help improve thermodynamic efficiency of the heat recovery process. This image represents the molecular makeup of one of several MOHCs.
Richland, Wash. - A new method for capturing significantly more heat from low-temperature geothermal resources holds promise for generating virtually pollution-free electrical energy. Scientists at the Department of Energy's Pacific Northwest National Laboratory will determine if their innovative approach can safely and economically extract and convert heat from vast untapped geothermal resources.

The goal is to enable power generation from low-temperature geothermal resources at an economical cost. In addition to being a clean energy source without any greenhouse gas emissions, geothermal is also a steady and dependable source of power.
      Read More...
Info

Learning is social, computational, supported by neural systems linking people

Joel Schwarz
University of Washington
Thu, 16 Jul 2009 22:42 UTC
Education is on the cusp of a transformation because of recent scientific findings in neuroscience, psychology, and machine learning that are converging to create foundations for a new science of learning.

Writing in Friday's (June 17) edition of the journal Science, researchers report that this shift is being driven by three principles that are emerging from cross-disciplinary work: learning is computational, learning is social, and learning is supported by brain circuits linking perception and action that connect people to one another. This new science of learning, the researchers believe, may shed light into the origins of human intelligence.
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Meteor

Primitive Asteroids In Main Asteroid Belt May Have Formed Far From The Sun


Science Daily
Thu, 16 Jul 2009 08:41 UTC
micrometeorite
© CSNSM-Orsay-CNRS / IPEV
Researchers collected this micrometeorite in the vicinity of CONCORDIA station in central Antarctica (Dome C, 73°S, 123°E)
Many of the objects found today in the asteroid belt located between the orbits of Mars and Jupiter may have formed in the outermost reaches of the solar system, according to an international team of astronomers led by scientists from Southwest Research Institute (SwRI).

The team used numerical simulations to show that some comet-like objects residing in a disk outside the original orbit of the planets were scattered across the solar system and into the outer asteroid belt during a violent phase of planetary evolution.

Usually, the solar system is considered a place of relative permanence, with changes occurring gradually over hundreds of millions to billions of years. New models of planet formation indicate, however, that at specific times, the architecture of the solar system experienced dramatic upheaval.

In particular, it now seems probable that approximately 3.9 billion years ago, the giant planets of our solar system -- Jupiter, Saturn, Uranus and Neptune -- rearranged themselves in a tumultuous spasm. "This last major event of planet formation appears to have affected nearly every nook and cranny of the solar system," says lead author Dr. Hal Levison of SwRI.
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