Posted by hipstom
Kibardin Design’s suh-weet Deep Forest chair is the opposite of all of the “holey” chairs we’ve been seeing lately; it’s made from 374 dowels, joined and shaped into a comfortable seating surface. As you might guess, this amount of craftsmanship doesn’t come cheap–the chair goes for 4,399 Euros.
http://www.core77.com/blog/object_culture/kibardin_designs_anti-holey_chair_15145.asp
Nanotube fiber: This fiber, which is about 40 micrometers in diameter, is made up of carbon nanotubes. Credit: Rice University
Researchers have taken a step towards making carbon nanotubes into transmission lines.
A new method for assembling carbon nanotubes has been used to create fibers hundreds of meters long. Individual carbon nanotubes are strong, lightweight, and electrically conductive, and could be valuable as, among other things, electrical transmission wires. But aligning masses of the nanotubes into well-ordered materials such as fibers has proven challenging at a scale suitable for manufacturing. By processing carbon nanotubes in a solution called a superacid, researchers at Rice University have made long fibers that might be used as lightweight, efficient wires for the electrical grid or as the basis of structural materials and conductive textiles.
Others have made carbon-nanotube fibers by pulling the tubes from solid hair-like arrays or by spinning them like wool as they emerge from a chemical reactor. The problem with starting from a solid, says Rice chemical engineering professor Matteo Pasquali, is that “the alignment is not spectacular, and these methods are difficult to scale up.” The better aligned and ordered the individual nanotubes in a larger structure, the better the collective structure’s electrical and mechanical properties. Using the Rice methods, well-aligned nanotube fibers can be made on a large scale, shot out from a nozzle similar to a showerhead.
The late Nobel laureate Richard Smalley started the Rice project in 2001. Smalley knew solution-processing would be a good way to assemble nanotube fibers and films because of nanotubes’ shape. Carbon nanotubes are much longer than they are wide, so when they’re in a flowing solution, they line up like logs floating down a river. But carbon nanotubes aren’t soluble in conventional solvents. The Rice group laid the foundations for liquid processing of the nanotubes five years ago, when they discovered that sulfuric acid brings the nanotubes into solution by coating their surfaces with positively charged ions.
For the past five years, the Rice group has used microscopy to study nanotube solutions made in several different acids. “There was no quick experiment,” Pasquali says. “We had to be very deliberate. We now understand how the solution processing works, the knobs to control the nanotubes, and how to predict what they’ll do.” The best solvent for processing the tubes, according to work published this month in the journal Nature Nanotechnology, is chlorosulphonic acid. Nanotubes spontaneously dissolve in this acid at concentrations 1,000 times greater than they do in any other solvent.
The Rice group has used acid processing methods to assemble carbon nanotubes into fibers 50 micrometers thick and hundreds of meters long. “There are no limitations on the fiber length,” says Pasquali. The Rice group demonstrated its assembly method with high-quality, single-walled carbon nanotubes.
So far, the group has made fibers that are highly conductive but not as strong as other carbon materials. Pasquali says the strength of the fibers could probably be improved tenfold by using longer carbon nanotubes. “We’re now working on a project for making electrical transmission lines,” says Pasquali. “Metallic nanotubes conduct electricity better than copper, they’re lighter, and they fail less often.”
One important hurdle for large-scale manufacturing of carbon nanotubes remains: Today, there aren’t any good methods for making the nanotubes themselves in large, pure batches. In order to make nanotube transmission lines, for example, the Rice group would need to start with a large batch of nanotubes containing all metallic nanotubes and no semiconducting ones. Last month, chemists at the Honda Research Institute published a paper in Science describing a method for making large amounts of metallic nanotubes that Pasquali says is promising. “For transmission lines you need to make tons, and there are no methods now to do that,” he says. “We are one miracle away.”
Seeing the light: A new contact lens technology responds to UV light. The contact lens on the left (blue) contains photochromic dyes that darken the lens in the presence of UV light. The contact lens on the right (clear) contains no dyes. Credit: Institute for Bioengineering and Nanotechnology
UV-responsive dyes embedded in contact lenses can quickly adapt.
By Jennifer Chu
Transition lenses–which darken automatically in response to bright sunlight–have been available for eyeglasses for 40 years. But adapting this flexibility to contact lenses has proven challenging. Now researchers in Singapore have developed UV-responsive, or photochromic, lenses that darken when exposed to ultraviolet light, protecting the eyes against the sun’s damaging rays, and return to normal in UV’s absence.
The key is a novel polymer laced with an intricate network of nano-sized tunnels that can be filled with dyes. Initial studies have shown that the technology performs faster than the transition sunglasses on the market today, says Jackie Ying, director of the Institute for Bioengineering and Nanotechnology (IBN) in Singapore, and developer of the lenses. The research is part of a broader effort at IBN to develop new materials for contact lenses that can dispense drugs and diagnose diseases.
Conventional transition sunglasses are coated with millions of molecules of photochromic dyes, which are transparent when out of the sun. These molecules change shape when UV light hits, enabling them to absorb UV light and triggering the darkening of the lens. When UV light disappears, the molecules change back to their original shape and transparent appearance.
Few previous attempts have been made to design transition contact lenses, largely because it’s difficult to apply dye coatings uniformly to the delicate, soft surface of a contact lens. Ying and her colleagues got around this by developing a contact lens that embeds dyes uniformly throughout the material. This approach allowed them to pack more dye molecules into the material, Ying says, giving the contact lens greater sensitivity to light and thus a faster response.
Researchers created the spongy nanostructure material by mixing specific combinations of water, an oil solution with monomers commonly used in contact lenses, and a novel surfactant– a compound that encourages mixing between water and oil solutions. The resulting material is studded with tiny pores and tunnels, which can be loaded with agents such as UV-sensitive dyes.
The lens material’s porous structure provides a flexible environment for dyes to transform from dark to light and back again, says Edwin Chow, team leader and senior research scientist at IBN. “If the polymer is too rigid, the dye is stuck and can’t transform,” says Chow. “This pore structure and polymer happens to give the best environment for dyes to react quickly.”
Article Continues – http://www.technologyreview.com/biomedicine/23922/
by Darren Murph
We’re still reserving our doubts about the viability of the enTourage eDGe — after all, at $490 you can buy yourself a respectable netbook and a halfway decent ereader for the appropriate occasion — but we won’t say that we’re not interested. Just under a month after it hit the scene, the dual-screen device has landed (in prototype form) over at Gearlog, and while some of the features weren’t functional, the physical build shouldn’t change much when it goes final. At first glance, the whole thing just looks a bit dated, but then again, we’ve still got the ultra-fresh Nook on the brain.
Follow the link for more details – http://www.engadget.com/2009/11/10/dual-screen-entourage-edge-ebook-reader-gets-a-little-hands-on-t/
WASTEWATER FOUNTAIN: Natural gas drilling in New York State could introduce unsafe levels of radiation into the drinking water. FLICKR/JOSHME17
By Abrahm Lustgarten and ProPublica
As New York gears up for a massive expansion of gas drilling in the Marcellus Shale, state officials have made a potentially troubling discovery about the wastewater created by the process: It’s radioactive. And they have yet to say how they’ll deal with it.
The information comes from New York State’s Department of Environmental Conservation, which analyzed 13 samples of wastewater brought thousands of feet to the surface from drilling and found that they contain levels of radium 226, a derivative of uranium, as high as 267 times the limit safe for discharge into the environment and thousands of times the limit safe for people to drink.
The findings, if backed up with more tests, have several implications: The energy industry would likely face stiffer regulations and expenses, and have more trouble finding treatment plants to accept its waste—if any would at all. Companies would need to license their waste handlers and test their workers for radioactive exposure, and possibly ship waste across the country. And the state would have to sort out how its laws for radioactive waste might apply to drilling and how the waste could impact water supplies and the environment.
What is less clear is how the wastewater may affect the health of New Yorkers, since the danger depends on how much radiation people are exposed to and how they are exposed to it. Radium is known to cause bone, liver and breast cancers, and the EPA publishes exposure guidelines for it, but there is still disagreement over exactly how dangerous low-level doses can be to workers who handle it, or to the public.
The DEC has yet to address any of these questions. But New York’s Health Department raised concerns about the amount of radioactive materials in the wastewater in a confidential letter to the DEC’s oil and gas regulators in July.
“Handling and disposal of this wastewater could be a public health concern,” DOH officials said in the letter, which was obtained by ProPublica. “The issues raised are not trivial, but are also not insurmountable.”
The letter warned that the state may have difficulty disposing of the drilling waste, that thorough testing will be needed at water treatment plants, and that workers may need to be monitored for radiation as much as they might be at nuclear facilities.
Health Department officials declined to comment on the letter. The DEC sent an e-mail response to questions about the radioactivity stating that “concentrations are generally not a problem for water discharges, or in solid waste streams” in New York State. But the agency did not directly address the radioactivity levels, which were disclosed in the appendices of the agency’s environmental review of gas drilling in the Marcellus Shale, released September 30.
The review did not calculate how much radioactivity people may be exposed to, even though such calculations are routinely completed by scientists studying radiation exposure. Yet the review concluded that radiation levels were “very low” and that the wastewater “does not present a risk to workers.” DEC officials declined to explain how they reached this conclusion.
Although the review pointed to a possible need for radioactive licensing and disposal for certain materials, and it looked at other states with laws aimed at radioactive waste from drilling, the DEC said there is no precedent for examining how these radioactive materials might affect the environment when brought to the surface at the volumes and scale expected in New York. And it said that more study is needed before the DEC can lay out precise plans to deal with the waste.
Article Continues – http://www.scientificamerican.com/article.cfm?id=marcellus-shale-natural-gas-drilling-radioactive-wastewater
Illustration of rat with spinal injury. (Credit: Image courtesy of University of California – Irvine)
The first human embryonic stem cell treatment approved by the FDA for human testing has been shown to restore limb function in rats with neck spinal cord injuries — a finding that could expand the clinical trial to include people with cervical damage.
In January, the U.S. Food & Drug Administration gave Geron Corp. of Menlo Park, Calif., permission to test the UC Irvine treatment in individuals with thoracic spinal cord injuries, which occur below the neck. However, trying it in those with cervical damage wasn’t approved because preclinical testing with rats hadn’t been completed.
Results of the cervical study currently appear online in the journal Stem Cells. UCI scientist Hans Keirstead hopes the data will prompt the FDA to authorize clinical testing of the treatment in people with both types of spinal cord damage. About 52 percent of spinal cord injuries are cervical and 48 percent thoracic.
“People with cervical damage often have lost or impaired limb movement and bowel, bladder or sexual function, and currently there’s no effective treatment. It’s a challenging existence,” said Keirstead, a primary author of the study. “What our therapy did to injured rodents is phenomenal. If we see even a fraction of that benefit in humans, it will be nothing short of a home run.”
A week after test rats with 100 percent walking ability suffered neck spinal cord injuries, some received the stem cell treatment. The walking ability of those that didn’t degraded to 38 percent. Treated rats’ ability, however, was restored to 97 percent.
UCI’s therapy utilizes human embryonic stem cells destined to become spinal cord cells called oligodendrocytes. These are the building blocks of myelin, the biological insulation for nerve fibers that’s critical to proper functioning of the central nervous system. When myelin is stripped away through injury or disease, paralysis can occur.
Lead author and doctoral student Jason Sharp, Keirstead and colleagues discovered that the stem cells not only rebuilt myelin but prevented tissue death and triggered nerve fiber regrowth. They also suppressed the immune response, causing an increase in anti-inflammatory molecules.
“The transplant created a healing environment in the spinal cord,” said Keirstead, who is co-director of the Sue & Bill Gross Stem Cell Research Center and on the faculty of the Reeve-Irvine Research Center — named for late actor Christopher Reeve, who became a quadriplegic after a cervical spinal cord injury.
In addition to Keirstead and Sharp, Jennifer Frame, Monica Siegenthaler and Dr. Gabriel Nistor of UCI worked on the study, which was supported by Geron Corp., a University of California Discovery Grant, the Roman Reed Spinal Cord Injury Research Fund of California, Research for Cure, and individual donations to the Reeve-Irvine Research Center.
http://www.sciencedaily.com/releases/2009/11/091109121345.htm
This enhanced-color view was created with a statistical technique that highlights subtle color variations seen in the 11 filters of MESSENGER’s wide-angle camera that are often related to composition. Merged with images from the higher-resolution narrow-angle camera, the two sets of observations tell the story of the geology of the area and the compositional differences of the features observed. This region, viewed in detail for the first time during the third flyby, appears to have experienced a high level of volcanic activity. (Credit: Image courtesy of NASA)
A NASA spacecraft gliding over the battered surface of Mercury for the second time this year has revealed more previously unseen real estate on the innermost planet. The probe also has produced several science firsts and is returning hundreds of new photos and measurements of the planet’s surface, atmosphere and magnetic field.
The MErcury Surface, Space ENvironment, GEochemistry, and Ranging, or MESSENGER, spacecraft flew by Mercury shortly after 4:40 a.m. EDT, on Oct. 6. It completed a critical gravity assist to keep it on course to orbit Mercury in 2011 and unveiled 30 percent of Mercury’s surface never before seen by a spacecraft.
“The region of Mercury’s surface that we viewed at close range for the first time this month is bigger than the land area of South America,” said Sean Solomon, principal investigator and director of the Department of Terrestrial Magnetism at the Carnegie Institution of Washington. “When combined with data from our first flyby and from Mariner 10, our latest coverage means that we have now seen about 95 percent of the planet.”
The spacecraft’s science instruments operated throughout the flyby. Cameras snapped more than 1,200 pictures of the surface, while topography beneath the spacecraft was profiled with a laser altimeter. The comparison of magnetosphere observations from the spacecraft’s first flyby in January with data from the probe’s second pass has provided key new insight into the nature of Mercury’s internal magnetic field and revealed new features of its magnetosphere. The magnetosphere is the volume surrounding Mercury that is controlled by the planet’s magnetic field.
“The previous flybys by MESSENGER and Mariner 10 provided data only about Mercury’s eastern hemisphere,” explains Brian Anderson of the Johns Hopkins University Applied Physics Laboratory, known as APL, in Laurel, Md. “The most recent flyby gave us our first measurements on Mercury’s western hemisphere, and with them we discovered that the planet’s magnetic field is highly symmetric.”
The probe’s Mercury Laser Altimeter, or MLA, measured the planet’s topography, allowing scientists, for the first time, to correlate high-resolution topography measurements with high-resolution images.
“The MLA collected altimetry in regions where images from MESSENGER and Mariner 10 data are available, and new images were obtained of the region sampled by the altimeter in January,” said Maria Zuber, co-investigator and head of the Department of Earth, Atmospheric, and Planetary Sciences at the Massachusetts Institute of Technology. “These topographic measurements now improve considerably the ability to interpret surface geology.”
The Mercury Atmospheric and Surface Composition Spectrometer observed Mercury’s thin atmosphere, known as an exosphere. The instrument searched for emissions from sodium, calcium, magnesium, and hydrogen atoms. Observations of magnesium are the first detection of this chemical in Mercury’s exosphere. Preliminary analysis suggests that the spatial distributions of sodium, calcium, and magnesium are different. Simultaneous observations of these spatial distributions, also a first for the spacecraft, have opened an unprecedented window into the interaction of Mercury’s surface and exosphere.
Spacecraft images also are revealing for the first time vast geologic differences on the surface.
“Now that MESSENGER’s cameras have imaged more than 80 percent of Mercury, it is clear that, unlike the moon and Mars, Mercury’s surface is more homogeneously ancient and heavily cratered, with large extents of younger volcanic plains lying within and between giant impact basins,” said co-investigator Mark Robinson of Arizona State University in Tempe.
The project is the seventh in NASA’s Discovery Program of lower-cost, scientifically focused missions. APL designed, built and operates the spacecraft and manages the mission for NASA’s Science Mission Directorate in Washington. Science instruments were built by APL; NASA’s Goddard Space Flight Center in Greenbelt, Md.; the University of Michigan, Ann Arbor; and the University of Colorado, Boulder. GenCorp Aerojet of Sacramento, Calif., and Composite Optics Inc. of San Diego, provided the propulsion system and composite structure.
For more information about the Mercury mission, visit: www.nasa.gov/messenger
http://www.sciencedaily.com/releases/2009/11/091108215449.htm
Unlike humans, zebrafish are able to regenerate amputated appendages. (Credit: Courtesy of the Salk Institute)
The search for the holy grail of regenerative medicine — the ability to “grow back” a perfect body part when one is lost to injury or disease — has been under way for years, yet the steps involved in this seemingly magic process are still poorly understood.
Now researchers at the Salk Institute for Biological Studies have identified an essential cellular pathway in zebrafish that paves the way for limb regeneration by unlocking gene expression patterns last seen during embryonic development. They found that a process known as histone demethylation switches cells at the amputation site from an inactive to an active state, which turns on the genes required to build a copy of the lost limb.
“This is the first real molecular insight into what is happening during limb regeneration,” says first author Scott Stewart, Ph.D., a postdoctoral researcher in the lab of Juan Carlos Izpisúa Belmonte, Ph.D., who led the Salk team. “Until now, how amputation is translated into gene activation has been like magic. Finally we have a handle on a process we can actually follow.”
Their findings, which will be published in a forthcoming issue of Proceedings of the National Academy of Sciences, U.S.A., help to explain how epimorphic regeneration — the regrowing of morphologically and functionally perfect copies of amputated limbs — is controlled, an important step toward understanding why certain animals can do it and we cannot.
“Our experiments show that normal development and limb regeneration are controlled by similar mechanisms,” explains Izpisúa Belmonte, a professor in the Gene Expression Laboratory. “This finding will help us to ask more specific questions about mammalian limb regeneration: Are the same genes involved when we amputate a mammalian limb? If not, what would happen if we turned them on? And if we can affect these methylation marks in an amputated limb, what effect would that have?”
The Belmonte lab uses zebrafish, a small fish from the minnow family, to study limb regeneration. “If you amputate the tail of the zebrafish, it regenerates in about a week, seemingly with no effort and leaving no scar,” explains Stewart. “What’s more, it regenerates a perfect copy and — like growing grass — it will do this over and over again.”
Since regeneration recapitulates in broad strokes embryonic development, during which a complex multi-cellular organism develops from a handful of embryonic stem cells, the researchers began by comparing gene expression patterns between the two processes. During development, genes within specific cell types are turned on and off to trigger the necessary expression patterns that create a whole animal. Once their job is done, they lie silently till they are turned on once again following amputation.
Based on these similarities, Stewart reasoned that genes involved in regeneration may share silencing mechanisms with the ones active in embryonic stem cells. Embryonic stem cells are maintained in a ready-to-go state, “poised” for action to become whatever cell type is needed. The key to this “poised” state are histones, DNA packaging proteins that are also used as carriers for chemical modifications, such as methylation and acetylation. These chemical marks serve as “on” and “off” switches for specific genes.
Stewart discovered that the histone modifications that poise embryonic stem cell-specific genes for activation are also found on the histones near genes involved in regeneration, putting them into a ready-to-go state. “This suggests that two different gene expression programs may exist; one for normal cellular activity and one for regeneration,” explains Stewart. To test this hypothesis, the team looked at the histone marks during regeneration. As suspected, they saw a reduction in “off” switches and an increase in “on” switches in regenerating tissue, tipping the balance toward gene expression.
Delving deeper, the researchers found that enzymes that remove the “off” mark, so-called demethylases, are present in high levels in regenerating tissue. One enzyme in particular, called Kdm6b.1, is found exclusively in cells that are undergoing the regeneration process. Without Kdm6b.1, zebrafish failed to regenerate amputated fins, meaning removal of the “off” mark is a prerequisite for fin regeneration.
In the long term, the Salk researchers hope that these findings will help them understand whether we can affect the outcome of mammalian limb regeneration. In the more immediate future, the team plans to use global approaches to identify all the targets of Kdm6b.1 during regeneration, and to find out what gives the signal to turn these genes off when regeneration is complete.
In addition to Stewart and Izpisúa Belmonte, Zhi-Yang Tsun, also contributed to the study.
The study was funded in part by the California Institute for Regenerative Medicine, the Fundacion Cellex, the G. Harold and Leila Y. Mathers Charitable Foundation, the Ipsen Foundation, and the National Institutes of Health.
http://www.sciencedaily.com/releases/2009/11/091102171419.htm
(Top left) Schematic of Cerenkov radiation in a conventional natural medium with positive refractive index, such as water, in which the radiation falls in a cone in the forward direction. (Bottom left) Schematic of backward Cerenkov radiation in a left-handed medium, showing the reversed cone. (Right) Schematic of the two-dimensional experimental configuration and the photographic image of the negative index metamaterials used to demonstrate backward Cerenkov radiation. The metamaterials consist of in-plane split-ring resonators and metal wires.
Physicists have developed a new metamaterial structure that successfully demonstrates reverse Cerenkov radiation. They have directly observed a reverse shock wave of light in a specially tailored structure known as a left-handed metamaterial.
Although it was first predicted over forty years ago, this is the first unambiguous experimental demonstration of the effect. The research is reported in Physical Review Letters and highlighted in the November 2 issue of Physics.
Light moving in a vacuum sets the ultimate speed limit, but light travels more slowly through materials like glass and air. Speedy electrons or other charged particles can briefly outrun light in matter, producing a shock wave in the form of a cone of light known as Cerenkov radiation. The eerie blue glow in the cooling water of nuclear reactors is result of particles moving faster than the speed of light in water. In normal substances, the radiation is emitted in a forward cone. Left-handed metamaterials, however, have unusual effects on light that should reverse the cone’s direction.
When light enters a normal material like glass, it changes direction, allowing us to make lenses that correct poor vision. When light enters a left-handed metamaterial, the change is opposite to the direction that would occur in normal materials. (The materials are “left-handed” because they affect light oppositely from “right-handed” normal materials.) This means that the cone of Cerenkov radiation from a faster-than-light particle should propagate backward in a left-handed metamaterial. But experimental difficulties have prevented confirmation of the effect despite its prediction in 1968.
Now a team of physicists at Zhejiang University in China and the Massachusetts Institute of Technology has developed a new metamaterial structure that successfully demonstrates reverse Cerenkov radiation. Instead of injecting faster-than-light particles into their metamaterial, they created an optical analogue of particles moving at twice light speed. This allowed them to produce a much stronger burst of reverse Cerenkov light than they could have gotten with a real particle beam. Besides verifying a decades-old theoretical prediction, the experiment suggests a new possible application of left-handed metamaterials as detectors of high-speed particles in accelerators and other experiments.
http://www.sciencedaily.com/releases/2009/11/091102111841.htm
IF YOU had come here 10 years ago, says Thaddeus Salah as he shows us round his tree nursery in north-west Cameroon, you would have seen real hunger and poverty. “In those times,” he says, “we didn’t have enough chop to eat.” It wasn’t just food – “chop” in the local dialect – that his family lacked. They couldn’t afford school fees, healthcare or even chairs for their dilapidated grass-thatch house.
Salah’s fortunes changed in 2000 when he and his neighbours learned how to identify the best wild fruit trees and propagate them in a nursery. “Domesticating wild fruit like bush mango has changed our lives,” he says. His family now has “plenty chop”, as he puts it. He is also earning enough from the sale of indigenous fruit trees to pay school fees for four of his children. He has been able to re-roof his house with zinc sheets and buy goods he could only dream of owning before. He even has a mobile phone.
From Salah’s farm we gaze across the intensively cultivated hills which roll away towards the Nigerian border. “Ten years ago, you’d hardly see any safou [African plum, Dacryodes edulis] in this area,” says Zachary Tchoundjeu, a botanist at the World Agroforestry Centre’s regional office in the Cameroonian capital Yaoundé. “Now you see them growing everywhere.”
The spread of African plum through these hills is one small part of a bigger movement that could change the lives of millions of Africans. The continent is home to some 3000 species of wild fruit tree, many of which are ripe for domestication. Chocolate berries, gingerbread plums, monkey oranges, gumvines, tree grapes and a host of others could soon play a role in ensuring dependable food supplies in areas now plagued by malnutrition (see “Future fruits of the forest”).
One of the architects of the programme is Roger Leakey, a former director of research at the World Agroforestry Centre. He calls these fruit trees “Cinderella species”: their attributes may have gone unrecognised by science and big business, but the time has come for them to step into the limelight.
“The last great round of crop domestication took place during the green revolution [in the mid-20th century], which developed high-yielding varieties of starchy staples such as rice, maize and wheat,” says Leakey. “This new round could scarcely be more different.” Sparsely funded and largely ignored by agribusiness, high-tech labs and policy-makers, it is a peasant revolution taking place in the fields of Africa’s smallholders.
The revolution has its roots in the mid-1990s, when researchers from the World Agroforestry Centre conducted a series of surveys in west Africa, southern Africa and the Sahel to establish which indigenous trees were most valued by local people. “We were startled by the results,” says Tchoundjeu. “We were expecting people to point to commercially important timber species, but what they valued most were indigenous fruit trees.”
In response to this unexpected finding, the World Agroforestry Centre launched a fruit tree domestication programme in 1998. It began by focusing on a handful of species, including bush mango (Irvingia gabonensis), an indigenous African species unrelated to the Indian mango, African plum – not actually a plum but a savoury, avocado-like fruit sometimes called an afrocado – and a nut tree known locally as njansan (Ricinodendron heudelotii). Though common in the forests and as wild trees on farms, they were almost unknown to science. “We knew their biological names, but that was about all,” says Ebenezar Asaah, a tree specialist at the World Agroforestry Centre. “We had no idea how long it took for them to reach maturity and produce fruit, and we knew nothing about their reproductive behaviour.” Local people, in contrast, knew a good deal about them, as the trees’ fruits have long been part of their diet.
Rural Africans consume an enormous variety of wild foodstuffs. In Cameroon, fruits and seeds from around 300 indigenous trees are eaten, according to a study by researchers at Cameroon’s University of Dschang. A similar survey in Malawi and Zambia found that up to 40 per cent of rural households rely on indigenous fruits to sustain them during the “hungry months”, particularly January and February, when supplies in their granaries are exhausted and they are waiting for their next harvest (Acta Horticulturae, vol 632, p 15).
Some of these so called “famine foods” have already been domesticated by accident, says ethnoecologist Anthony Cunningham of People and Plants International, an NGO based in Essex Junction, Vermont. He cites the example of marula (Sclerocarya birrea), a southern African tree in the cashew family with edible nutty seeds encased in a tart, turpentine-flavoured fruit. “Long before the development of agricultural crops, hunter-gatherers were eating marula fruit,” he says. “They’d pick the best fruit, then scatter the seeds around their camps.” These would eventually germinate and mature into fruit-bearing trees, ensuring, in evolutionary terms, the survival of the tastiest. Marula is now fully domesticated and the fruit is used to make juice, a liqueur called Amarula Cream and cosmetic oils.
Article Continues - http://www.newscientist.com/article/mg20427331.200-cinderella-fruit-wild-delicacies-become-cash-crops.html
