Science talk returns to brighten your day one more time. 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 Arctic climate more vulnerable than thought, top predatory are key to extinctions as the planet warms, biodegradable artery graft may enhance bypass surgeries, chemical evidence of the first dairying in Saharan Africa, a China submersible breaks the 7000-meter mark, and renewables could fill 80 percent of American electricity demand by 2050.
Pull up that comfy chair and grab a spot on the porch. There is always plenty of room for everyone. Another session of Dr. Possum's science education, entertainment, and potluck discussion is set to begin.
Featured Stories
Analysis of the longest Arctic core to date substantiates warming periods far above what was thought before. These periods coincide with times during which parts of Antarctic were ice free.
(Researcher) Brigham-Grette and colleagues discuss two scenarios for future testing that could explain inter-hemispheric climate coupling. First, reduced glacial ice cover and loss of ice shelves in Antarctica could have limited formation of cold water masses that flow into the north Pacific and well up to the surface, resulting in warmer surface waters, higher temperatures and increased precipitation on nearby land. Alternatively, disintegration of the West Antarctic Ice Sheet likely led to a significant global sea level rise and allowed more warm surface water into the Arctic Ocean through the Bering Strait.
Not only do results shed light on natural variability of the Arctic climate, but this view of the past may be a key to understanding climate in future centuries, the researchers say."We have a lot more to learn," says Brigham-Grette. "But our results mesh with what glaciologists are seeing today. Seven of the 12 major ice shelves around the Antarctic are melting or are gone. We suspect the tipping point for the gradual de-glaciation of Greenland and the Arctic may be lower than glaciologists once thought."
As the climate warms and scientists continue to predict the effect on various animal species there must be an accounting for the
effect of predators on surviving species.
...research has shown that top consumers—predators and herbivores—have an especially strong effect on many other species. In a warming world, these species are “biotic multipliers,” increasing the extinction risk and altering the ranges of many other species in the food web.
“Climate change is likely to have strong effects on top consumers. As a result, these effects can ripple through an entire food web, multiplying extinction risks along the way,” said (researcher) Dave Skelly.
As advances in medicine continue day by day now comes the announcement of a
biodegradable artery graft for use in bypass surgery.
(Researcher) Wang and his colleagues made grafts as small as 1 mm in diameter and monitored the graft's transformation in vivo for three months. Because the graft was highly porous, cells were easily able to penetrate the graft wall, and mononuclear cells occupied many of the pores within three days. Within 14 days, smooth muscle cells -- an important blood vessel builder -- appeared. At 28 days, cells were distributed more evenly throughout the graft. At 90 days, most inflammatory cells were gone, which correlated with the disappearance of the graft materials. The artery was regenerated in situ and pulsed in sync with the host. Furthermore, the composition and properties of the new arteries are nearly the same as native arteries.
Analysis of unglazed pottery from Saharan Africa shows evidence of
dairying in pre-historic times.
By analysing fatty acids extracted from unglazed pottery excavated from an archaeological site in Libya, the researchers showed that dairy fats were processed in the vessels. This first identification of dairying practices in the African continent, by prehistoric Saharan herders, can be reliably dated to the fifth millennium BC.
Around 10,000 years ago the Sahara Desert was a wetter, greener place; early hunter-gatherer people in the area lived a semi-sedentary life, utilising pottery, hunting wild game and collecting wild cereals. Then, around 7,000-5,000 years ago as the region became more arid, the people adopted a more nomadic, pastoral way of life, as the presence of cattle bones in cave deposits and river camps suggests.
Domesticated animals were clearly significant to these people: the engraved and painted rock art found widely across the region includes many vivid representations of animals, particularly cattle. However, no direct proof that these cattle were milked existed – until now.
A new national record for manned exploration of the ocean depths was announced this week as a
Chinese submersible broke the 7000-meter mark.
The Jiaolong -- named after a dragon from Chinese mythology -- carried three people into the Mariana Trench, the deepest place in the world.
Applause broke out as a depth gauge aboard the supporting ship Xiangyanghong registered more than 7,000 metres, state television showed.
The same submersible reached 5,188 metres in a Pacific dive in July last year. And in a series of three previous dives since June 15, the craft has gone deeper each time. Experts say 7,000 metres is the limit of its design.
Earlier this year, American film director James Cameron descended almost 11,000 metres to the bottom of the Mariana Trench.
As the demand for and the supply of
renewable energy resources continues to climb a very positive report suggests filling 80 percent of US electricity is possible by 2050.
Reaching an 80 percent-renewables goal by 2050, says the study, will involve fifty percent of electricity coming from wind and photovoltaics. “The analysis treats a variety of scenarios with prescribed levels of renewable electricity generation in 2050, from 30% to 90%, with a focus on 80% (with nearly 50% from variable wind and solar photovoltaic generation).”
A diverse mix of renewable energy resources, such as geothermal, solar, wind and wave energy, can support multiple combinations of renewable technologies. The results would be meaningful reductions in electric sector greenhouse gas emissions and water use. The study finds no geographical gaps in achieving the 2050 goal. "All regions of the United States could contribute substantial renewable electricity supply in 2050, consistent with their local renewable resource base."
Hydropower is the biggest renewable contributor, but hydropower plays less of a role over the next few decades. NREL (National Renewable Energy Laboratory) suggests a growing role for offshore wind. NREL also says dedicated biomass power plants, as opposed to just feeding biomass to coal plants, are needed.
The study is significant as the most comprehensive analysis of high-penetration renewable electricity of the United States to date.
Perhaps all we lack is the political will to stand against the fossil fuel interests. We shall see...
Knucklehead's Photo of the Week
Fluffy
(being transferred to another tank. Capture time for transfer, 1 year)
©Knucklehead, all rights reserved. (Click on the image to see more in the same series.)
Other Worthy Stories of the Week
Chance alignment between galaxies mimics cosmic collision
Most quasars live on snacks not large meals
Compact blue dwarf can't hide from Hubble
The toughest life on Earth
Stonehenge was a monument marking the unification of Britain
Giant Ibex lived in the southern Pyrenees after the Ice Age
"Carbon capture' too risky and earthquake prone: Study
Bigger wind turbines make greener electricity
Greater L.A. to heat up by 4 to 5 degrees average by mid-century
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
Enhanced color picture of Mars rocks, NASA, public domain