Here we are once again. Science talk has arrived. New discoveries, new takes on old knowledge, and other bits of news are all available for the perusing in today's information world. Over the fold are selections from the past week from a few of the many excellent science news sites around the world. Today's tidbits include Asia was settled in multiple waves of migration, an edible carbon dioxide sponge, the rate of plant photosynthesis may be faster than thought, engineers 'cook' new heat harvesting nanomaterials in microwave oven, 'superfast' muscles aid bat echolocation, fossil of newborn dinosaur discovered. Pull up that comfy chair and bask in the sunshine. There is plenty of room for everyone. Get ready for another session of Dr. Possum's science education and entertainment.
Featured Stories
Researchers studying DNA patterns from modern and ancient humans uncovered new clues about the intermixing of populations in the settling of Asia.
The study demonstrates that contrary to the findings of the largest previous genetic studies, modern humans settled Asia in more than one migration. According to David Reich, a professor of genetics at Harvard Medical School, “Denisova DNA is like a medical imaging dye that traces a person’s blood vessels. It is so recognizable that you can detect even a little bit of it in one individual. In a similar way, we were able to trace Denisova DNA in the migrations of people. This shows the power of sequencing ancient DNA as a tool for understanding human history.”
The patterns the researchers found can only be explained by at least two waves of human migration: the first giving rise to the aboriginal populations that currently live in Southeast Asia and Oceania, and later migrations giving rise to relatives of East Asians who now are the primary population of Southeast Asia.
Scientists discovered a series of nanocompounds made of salt, sugar, and and alcohol and reported the finding about a year ago. Now the same compounds have been found to be capable of absorbing large amounts of carbon dioxide making in effect an edible carbon dioxide sponge.
The porous crystals -- known as metal-organic frameworks (MOFs) -- are made from all-natural ingredients and are simple to prepare, giving them a huge advantage over other MOFs. Conventional MOFs, which also are effective at adsorbing carbon dioxide, are usually prepared from materials derived from crude oil and often incorporate toxic heavy metals.
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The main component, gamma-cyclodextrin, is a naturally occurring biorenewable sugar molecule that is derived from cornstarch.
The sugar molecules are held in place by metals taken from salts such as potassium benzoate or rubidium hydroxide, and it is the precise arrangement of the sugars in the crystals that is vital to their successful capture of carbon dioxide.
Photosynthesis is an integral part of the processing of carbon dioxide in the atmosphere.
A team led by postdoctoral researcher Lisa Welp considered the oxygen atoms contained in the carbon dioxide taken up by plants during photosynthesis. The ratio of two oxygen isotopes in carbon dioxide told researchers how long the CO2 had been in the atmosphere and how fast it had passed through plants. From this, they estimated that the global rate of photosynthesis is about 25 percent faster than thought.
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The authors said the new estimate of the rate of global photosynthesis enabled by their method will in turn help guide other estimates of plant activity such as the capacity of forests and crops to grow. Understanding such variables is becoming increasingly important to scientists and policymakers attempting to understand the potential changes to ecosystems that can be expected from global warming.
Waste heat is lost energy that may be put to better uses if harvested.
Harvesting electricity from waste heat requires a material that is good at conducting electricity but poor at conducting heat. One of the most promising candidates for this job is zinc oxide, a nontoxic, inexpensive material with a high melting point. While nanoengineering techniques exist for boosting the electrical conductivity of zinc oxide, the material’s high thermal conductivity is a roadblock to its effectiveness in collecting and converting waste heat. Because thermal and electrical conductivity are related properties, it’s very difficult to decrease one without also diminishing the other.
However, a team of researchers led by Ganpati Ramanath, professor in the Materials Science and Engineering Department at Rensselaer, in collaboration with the University of Wollongong, Australia, have demonstrated a new way to decrease zinc oxide’s thermal conductivity without reducing its electrical conductivity. The innovation involves adding minute amounts of aluminum to zinc oxide, and processing the materials in a microwave oven. The process is adapted from a technique invented at Rensselaer by Ramanath, graduate student Rutvik Mehta, and Theo Borca-Tasciuc, associate professor in the Department of Mechanical, Aerospace, and Nuclear Engineering (MANE). This work could open the door to new technologies for harvesting waste heat and creating highly energy efficient cars, aircraft, power plants, and other systems.
Bats are nocturnal animals which navigate by echolocation, bouncing sound waves off objects.
Superfast muscles are capable of contraction about 100 times faster than typical body muscles and as much as 20 times faster than the fastest human muscles, those that control eye movement.
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With vision, animals receive a more-or-less continuous stream of information about the world. With echolocation, however, bats only get a snapshot of their environment with each call and echo, requiring them to make rapid successions of calls. When hunting a flying insect that can quickly move in any direction, bats need the most rapid updates on their prey’s position in the instant before the catch. At this critical point, bats produce what is known as the “terminal buzz,” where they make as many as 190 calls per second.
The fossil of a newborn nodosaur has been found in Maryland.
It is the youngest nodosaur ever discovered, and a founder of a new genus and species that lived approximately 110 million years ago during the Early Cretaceous Era. Nodosaurs have been found in diverse locations worldwide, but they've rarely been found in the United States.
Other Worthy Stories of the Week
Earth-shattering science is relatively rare
Neutrinos and the speed of light: A primer on the CERN study
Invisible ink made out of engineered bacteria
Sunspot 1302 big, bad and coming right at us
Nitrate levels are rising in the Northwestern Pacific
Orange peels could be made into biodegradable plastic
Existence of first exoplanet to be photographed called into question
Prehistoric colors preserved in near-perfect beetle fossilsM
Venus weather not boring after all
The sounds of NASA now available for download
Mars Express finds water supersaturation in the Martian atmosphere
Astronomers crack the fried egg nebula
Astronomers reveal supernova factory
Scientists release the most accurate simulation of the universe yet
New flavors emerge from Peruvian cacao collection trip
Sexting driven by peer pressure
Light from galaxy clusters confirm theory of relativity
Tree frogs chill out to collect precious water
Weeds are vital to the existence of farmland species
For even more science news:
General Science Collectors:
Alpha-Galileo
BBC News Science and Environment
Eureka Science News
LiveScience
New Scientist
PhysOrg.com
SciDev.net
Science/AAAS
Science Alert
Science Centric
Science Daily
Scientific American
Space Daily
Blogs:
A Few Things Ill Considered Techie and Science News
Cantauri Dreams space exploration
Coctail Party Physics Physics with a twist.
Deep Sea News marine biology
Laelaps more vertebrate paleontology
List of Geoscience Blogs
ScienceBlogs
Space Review
Techonology Review
Tetrapod Zoologyvertebrate paleontology
Science Insider
Scientific Blogging.
Space.com
Wired News
Science RSS Feed: Medworm
The Skeptics Guide to the Universe--a combination of hard science and debunking crap
At Daily Kos:
This Week in Science by DarkSyde
Overnight News Digest:Science Saturday by Neon Vincent. OND tech Thursday by rfall.
Pique the Geek by Translator Sunday evenings about 9 Eastern time
All diaries with the DK GreenRoots Tag.
All diaries with the eKos Tag
A More Ancient World by matching mole
Astro Kos
SciTech at Dkos.
Sunday Science Videos by palantir
NASA picture of the day. For more see the NASA image gallery or the Astronomy Picture of the Day Archive
NGC 281, NASA, Public Domain