Wednesday, March 26, 2014

3D construction of a blowfly in flight

There are a set of amazing reconstructions of the flight motion of a blowfly, available on YouTube, which show the workings of the muscles and exoskeleton. It looks like a steam engine. Very cool data visualization--  and a breakthrough in X-Ray technology to obtain the images.
YouTube #1

Thursday, March 13, 2014

Science of soccer ball aerodynamics

Deadspin has a great preview of the World Cup soccer ball, the Brazuca, and an analysis of whether the ball will swerve as much as the versions used in 2006 and 2010. Basically, knuckleball-like flight happens when the ball is under high drag, which occurs at low speeds.  In any soccer ball, the seams disturb the air flow and diminish drag,  making the ball's flight straight (its trajectory can be bent by spinning the ball). The South Africa World Cup ball, the Jabulani, had reduced seam depth, and therefore could "knuckle," exhibiting erratic behaviors due to high-drag flight, [YouTube] at much higher speeds than normal play balls would. The verdict on the Brazilian Brazuca ball is that its aerodynamics are likely to be to be much more like conventional balls. The blog entry has charts and imaging to make the case! Still can't wait.

Forged painting revealed by isotope analysis

The Contraste de Formes, now considered a fake.
Source: European Physical Journal 
There's a great detective story in the January issue of European Physical Journal, showing how a painting attributed to an artist can be proven to be a fake. The cotton fibers of the canvas in question showed the carbon-14 signature of the atomic age atmospheric tests, and the painting must therefore have been made after the death of the artist.
From about 1950 to 1963, testing of atomic bombs generated large amounts of carbon-14 in the atmosphere, sharply increasing the ratio of this isotope to the more common carbon-12. This atmospheric carbon-14 was taken up by living things worldwide, creating an unmistakable isotopic signature of the atomic era. This "bomb effect" carbon has been used to identify poached ivory , to give evidence for the birth of new neurons in the adult human brain, and to reveal a supposedly ancient mummy as a modern fake.
In the recent paper, the authors examined a canvas, Contraste de Formes,  in the Guggenheim collection in Venice. This canvas was purportedly one of a known series of paintings by this name painted by Fernand Leger, a cubist artist, between 1912 and 1914. Even in the 1970s, the owners of the painting had had some doubts about its authenticity.  This work was painted on cotton, not linen, and used different pigments for some colors compared to others in the series known to be from Leger. But these differences could not settle the question of whether Leger had painted it.
 In the new scientific study, the authors took a snippet of canvas and analyzed it for the carbon 14/carbon12 ratio. They found that carbon-14 was more than 40% higher than would be expected from a pre-atomic age item. Instead, the cotton plants used to make the canvas had to have been harvested in  1959 at the earliest. This final date settled the authorship question, as Leger died in 1955! The painting has to be a fake.

Thursday, March 06, 2014

Winter of 2013/2014-- ice coverage of Great Lakes nearing a record

Coverage of the Great Lakes on Feb 13, 2014. Paler shades
represent greater ice coverage. Source: NOAA
The Great Lakes system is more than 90% covered by ice right now, and is approaching the record of 95% set back in 1994. The ice is forming very rapidly now-- for example, Lake Superior was 78% covered in the last week of February, and is now at 95% coverage. The maximum ice cover of the lower lakes typically forms by the end of February, and the more northerly lakes max out a little bit later.
The ice cover on the lakes affects weather patterns over a large area, particularly to the east. Open water contributes to lake effect snow, and pulls the jet stream northward . The  winter severity of the lake system itself  is sensitive to worldwide atmospheric circulation events such as el Nino or la Nina.

Wednesday, March 05, 2014

30,000 year-old virus recovered from Permafrost

Nature has a news blurb about the isolation of a still-infectious viral particle from 30,000 year-old Siberian Permafrost. The story started with the 2012 report of the recovery of a blooming plant, which was germinated from fruits which had been cached in burrows by ancient squirrels. Researchers in France contacted the Russian field scientists and obtained soil samples from the same dig. The French team was interested in giant viruses, a recently discovered class which infects amoebas. So they basically exposed amoebas to the soil samples- and indeed, some samples contained a pathogen which killed the amoebas.
The new virus is named Pithovirus sibericum, and like other giant viruses, its genome is handled in an almost microbial fashion, with the large DNA genome not compacted, as in more familiar viruses. The DNA sequences have yielded lots of unknown sequences potentially encoding genes. It will be interesting to see how these viruses relate to the rest of the viral world, especially if there would be hints of another kingdom of life.