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Northern hemisphere forest biomass mapped

Thanks to satellites, the biomass of the northern hemisphere’s forests has been mapped with greater precision to help improve our understanding of the carbon cycle and our prediction of earth’s future climate. Accurately measuring forest biomass and how it varies are key elements for taking stock of forests and vegetation.

Since forests assist in removing carbon dioxide from the atmosphere, mapping forest biomass is also important for understanding the global carbon cycle.

 In particular, northern forests – including forest soil – store a third more carbon stocks per hectare as tropical forests, making them one of the most significant carbon stores in the world.

 The boreal forest ecosystem – exclusive to the northern hemisphere – spans Russia, northern Europe, Canada and Alaska, with interrelated habitats of forests, lakes, wetlands, rivers and tundra.  With processing software drawing in stacks of radar images from ESA’s Envisat satellite, scientists have created a map of the whole northern hemisphere’s forest biomass in higher resolution than ever before – each pixel represents 1 km on the ground.

“Single Envisat radar images taken at a wavelength of approximately 5 cm cannot provide the sensitivity needed to map the composition of forests with high density,” Maurizio Santoro from Gamma Remote Sensing said.

 “Combining a large number of radar datasets, however, yields a greater sensitivity and gives a more accurate information on what’s below the forest canopy,” Santoro said.
 About 70 000 Envisat radar images from October 2009 to February 2011 were fed into  this new, ‘hyper-temporal’ approach to create the pan-boreal map for 2010.
 This is the first radar-derived output on biomass for the whole northern zone using a single approach – and it is just one of the products from the Biomasar-II project.

Saliva on chewing gum, hair can reveal your secrets

If someone finds a piece of chewing gum you pitched today, he or she could use the saliva to sequence your DNA and read your book of life — including genetic secrets like your susceptibility to diseases. If that scenario causes a little discomfort, consider this - that stranger can also uses the DNA to reconstruct a copy of “you.”
Linda Wang, a senior editor of Chemical and Engineering News, the weekly newsmagazine of the American Chemical Society, the world’s largest scientific society, focuses on an unusual art exhibition that raises those and other unsettling questions.

The exhibit, ‘Stranger Visions,’ contains the work of Heather Dewey-Hagborg, a Ph.D. candidate in electronic arts at Rensselaer Polytechnic Institute.
Wang explains that at a time of concern and debate about the privacy of email and other personal communications, Dewey-Hagborg raises some of what may be the ultimate personal privacy issues. Dewey-Hagborg actually used genetic analysis and three-dimensional printing technology to produce facial sculptures of anonymous strangers.

 She collected their DNA from chewing gum, cigarette butts, strands of hair and other items that people have left behind in subways, bathrooms and other public places around New York City.

Bullfinches have ability to learn to sing human melodies

Bullfinches learn to sing melodies accurately from human teachers, a new study has revealed.

According to a new study by the late Nicolai Jurgen and researchers from the University of Kaiserslautern in Germany, the analysis of human melody singing in bullfinches gives insights into the songbirds’ brain processes.

The songs of free-living bullfinches are soft and contain syllables that are similar to the whistled notes of human melodies.

Teaching birds to imitate human melodies was a popular hobby in the 18th and 19th centuries and the bullfinch was the favourite species.

Using historical data recorded for 15 bullfinches, hand-raised by Jurgen Nicolai between 1967 and 1975, the researchers studied whether the bullfinches memorized and recalled the note sequence of the melodies in smaller subunits, as humans do, or in their entirety, as a linear chain, which is much simpler.

They also analysed the accuracy of the bullfinch’s choices and how a bird continues to sing after the human partner pauses. They focused on whether the bird chooses the right note sequence at the right time – so-called alternate singing.

When birds sing solo, they do not retrieve the learned melody as a coherent unit, but as modules, containing much smaller sub-sequences of 4-12 notes.  Researchers found evidence that as soon as the human starts whistling again, the birds can match the note sequence they hear to the memorised tune in their brain.

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