Thursday, September 25, 2014

The New Solar Cell


Now this is about a story stating about the success of a new invention - a cheap energy efficient solar cell. 
Olga Malinkiewicz, a PhD student studying photovoltaics at the University of Valencia in Spain, first heard about perovskites, the latest hope for low-cost solar power, in April last year. Unlike the slabs of purified silicon at the heart of the solar cells that currently dominate the market, perov­skites form thin films that are easily made in the lab by mixing together cheap salts.


Large, commercial silicon modules convert 17–25% of solar radiation into electricity, and much smaller perovskite cells have already reached a widely reproduced rate of 16–18% in the lab occasionally spiking higher. They are expected to top 20% in a few months.The combination of low cost and efficiency means that perovskite cells could, in theory, make solar power  which currently provides less than 1% of the world’s electricity  cheaper to generate than fossil-fuel energy.

The cells, composed of perovskite film sandwiched between conducting layers, are still about the size of postage stamps. To be practical, they must be scaled up, which causes efficiency to drop. It achieved 12% efficiency with 10 small cells wired together.

Doubts remain over whether the materials can survive for years when exposed to conditions outside the lab, such as humidity, temperature fluctuations and ultraviolet light. Researchers have also reported that ions inside some perovskite structures might shift positions in response to cycles of light and dark, potentially degrading performance.

What is perovskite ?

Perovskite is a calcium titanium oxide mineral composed of calcium titanate, with the chemical formulaCaTiO3. The mineral was discovered in the Ural Mountains of Russia by Gustav Rose in 1839 and is named after Russian mineralogist Lev Perovski

New Efficient Easy to make Solar Cell

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The Bending iPhone 6 Plus







Apple's new iPhone 6 and 6 Plus, which boast aluminum shells for lightness, apparently live up to that other characteristic of aluminum: malleability.


Reports of bent iPhone 6 and 6 Plus handsets are popping up on social media, and one product reviewer posted a video showing how far the larger frame can bend if one really, really tries.

On Twitter, it's being called #BendGate and #Bendghazi.

So far there has been no official response from Apple.

Smartphones bending in their pockets- iPhone 6 and iPhone 6 plus


Russell Holly, 29, decided to examine his new, silver iPhone 6 after seeing online reports of bent iPhones.

He noticed it wobbled on a flat surface. Then he compared it to the other iPhone 6 he bought. The bend was unmistakable. His confidence in the iPhone shaken, the mobile editor for Geek.com returned the phone.

Experts are divided over whether Apple should respond to claims that its new iPhone 6 handsets are prone to becoming bent when carried in trouser pockets.


Several members of the public have posted photos to the MacRumors site that appear to show the problem. A reporter for the Geek.com news site also reported his phone had warped.



The bigger screens but thinner bodies of Apple’s new iPhone 6 and 6 Plus models have come at the cost of rigidity, according to owners who say they bent while being carried in trouser pockets.

A number of users across various forums, sites and Twitter have reported – and pictured – that their phones have become warped after they sat or bent down with them in front and rear trouser pockets.


The reports come just after an insurance company claimed that the new iPhones are the most robust ever – though its tests didn’t include bending.

The iPhone 6 and 6 Plus chassis is milled from a solid piece of aluminium alloy whose composition is secret. The weak area of the phone appears to be around the volume buttons, where the frame is at its thinnest and creates a fulcrum point around which the phone bends. Surprisingly, the screen does not break when the phone bends – though it does if the phone is then bent back to a flat profile.

LG G Flex and the Samsung Galaxy Round

Handsets like the LG G Flex and the Samsung Galaxy Round have proved that manufacturers can make curved smartphones if they really want to, but with the iPhone 6 Plus it seems Apple is offering customers a do-it-yourself option.

Is iPhone 6 Plus Bending ?

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Syngenta Photography Awards 2014


Last Date of registration : 29 September 2014

The Syngenta Photography Award is an invitation to create images that make people stop and think. The Open Competition invites all photographers aged 18 or over – whether 
amateur, professional, or student – to visually explore this year’s theme Scarcity–  Waste through compelling images. 

Celebrating excellence 

All entries will be judged by a distinguished international judging panel chaired by the author and curator William A. Ewing. The jury members award three prizes in the Open Competition:


Open Competition  

• 1st  prize: US$5,000
• 2nd prize: US$3,000
• 3rd prize: US$2,000


Professional Competition

1st  prize: US$15,000
• 2nd prize: US$10,000
• 3rd prize: US$5,000


The winners will have their work featured in The International New York Times as well as showcased at an exhibition at Somerset House, London, in March 2015.  

The Theme - Scarcity Waste


In the past 50 years, the world’s demand for natural resources has doubled. If we continue to use resources and generate waste at the current rate, by 2030 we will need the equivalent of two planets. But we only have one. Clearly, something needs to change.

The second Syngenta Photography Award explores the theme of scarcity and waste. In a world of limited resources, these have become fundamental social, political and environmental issues of our time.

As population and economic growth drives increases in global consumption, many countries face growing resource shortages. Competition for, and even conflict over, resources such as fresh water, farm land, and forests is an increasing risk.

Resource scarcity is evident everywhere. From over-fished oceans to the rapidly disappearing rainforests, and from dust bowls to shrinking rivers and lakes. In China alone, over 27,000 rivers have disappeared in the last 60 years.

Already, 40% of the world’s farmland is seriously degraded and every second we lose an area of fertile land the size of a football field. This is in a world where nearly one billion people go to bed hungry and one in three people are affected by water scarcity.

Yet, it is a paradox that this scarcity exists side-by-side with enormous waste.

A third of the world’s food production is lost or wasted along the supply chain. In the UK, as much as 30% of vegetable crops are not harvested because they fail to meet the physical appearance standards expected by retailers. In India, around 40% of all fruit and vegetables are lost due to poor storage and transport systems. And across Europe and the US, over half of food purchased is simply thrown away. This isn’t just a waste of food, but of the land, water, inputs and labour that go into their cultivation.

With water use growing at twice the rate of population increases, many cities are struggling with inadequate infrastructure. In Jakarta, for example, 39% of the water is lost through pipe leaks. In Dhaka this rises to 50%, and in London water mains leak at least 25% of the city’s water. And waste as a by-product of an urban lifestyle is growing even faster than the rate of urbanization. In the US alone, over 100 million tons of household waste goes to landfill. Another 100 million tons is burnt or exported to poorer countries, with electronic waste putting up to 200 million people at risk of health and environmental hazards.

In a world that is so desperately short of resources, how can we ensure that there is land, food and water for everyone? How can we protect farmland against soil erosion and urbanization? How can we conserve vital ecosystems and biodiversity?

And what can we learn from the efforts of innovative communities to conserve, re-use and recycle?

The Syngenta Photography Award is a celebration of artistic skill and outstanding photography. It is a call for photographs that tell stories about scarcity, waste and the tensions and relationships between them. Photographers, whatever their approach, are invited to submit images that explore these important issues, and to spark a dialogue about our changing planet

Photography Awards 2014 Win US$ 15,000

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Thursday, September 18, 2014

Biospleen to Filter the Blood


The recent issue of Nature reported the development of a high-tech methodology to clean up the body from infection even if the causative pathogen is unknown. This device inspired by the Spleen to clean up the blood quickly and easily. This can be mentioned as an ‘artificial Biospleen’ to clean up the blood.

Knowing about Spleen


The spleen is the organ that is responsible for purifying the blood as well as storing blood cells. It is positioned in the superior abdomen, and is the largest lymphatic organ in the body. The spleen serves a valuable role in immune function because it purifies the blood and helps the immune system with recognize and attack foreign antibodies and disease. The spleen is composed of the red and white pulp. The white pulp produces and grows immune cell as well as blood cells. On the other hand, the red pulp is responsible for purifying the blood and removing dead or old blood cells.

Application of Artificial Biospleen

Infection in blood is difficult to identify and cure. Usually more than 50% of time physicians treat this by antibiotic which attack on broad range of pathogens. This approach is not always effective, and can lead to antibiotic resistance in bacteria.

In search of a way to clear any infection, a team led by Donald Ingber, a bioengineer at the Wyss Institute for Biologically Inspired Engineering in Boston, Massachusetts, developed an artificial 'biospleen' to filter blood.

The filtering technology


Scientist used modified version of Mannose binding Lectin (MBL). a protein found in humans that binds to sugar molecules on the surfaces of more than 90 different bacteria, viruses and fungi, as well as to the toxins released by dead bacteria that trigger the immune overreaction in sepsis.

The researchers coated magnetic nanobeads with MBL. As blood enters the Biospleen device, passes by the MBL-equipped nanobeads, which bind to most pathogens. A magnet on the Biospleen device then pulls the beads and their quarry out of the blood, which can then be routed back into the patient.

Testing of the Biospleen in infected rats showed that 90% of pathogens cleaned by the device in 5 hours. The researchers then tested whether the Biospleen could handle the volume of blood in an average adult human — about 5 litres. They ran human blood containing a mixture of bacteria and fungi through the Biospleen at a rate of 1 litre per hour, and found that the device removed most of the pathogens within five hours.

The Biospleen could also help to treat viral diseases such as HIV and Ebola, in which survival depends on lowering the amount of virus in the blood to a negligible level. This may be a future breakthrough device to save human life. 


Artificial Biospleen to Filter the Blood

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Wednesday, August 6, 2014

Turning carbon dioxide emissions into chemicals, fibres and jet fuel

A carbon revolution? Scientists are using the principles of photosynthesis to turn CO2 emissions into useful products

Shell is collaborating on a project in Switzerland that will produce jet fuel, using carbon dioxide, water and solar energy. Photograph: Gerolf Kalt/ Gerolf Kalt/Corbis

Bernie Bulkin

Monday 4 August 2014 13.28 BST

When fuels are burned, the products are carbon dioxide, water, and heat. Lots of heat. This heat takes energy out of the chemicals (say petrol, coal or gas) and releases it, leaving behind very low energy molecules, like CO2. A chemist's dream is to find efficient ways of putting this energy back into the carbon dioxide to turn it into something else useful. In other words, to convert a waste product that causes global warming into something useful.

If carbon dioxide is in a product that will keep it locked up for a long period of time, like furniture or building insulation, this is a way of removing it from the air: carbon capture. And CO2 is free or, given policies to make the emission of carbon dioxide a cost to business, it even becomes a starting material for chemistry that has a negative cost.

Luckily, nature already does what chemists aspire to. It efficiently takes carbon dioxide from the air, using energy from sunlight and natural catalysts, and converts it into the carbon building blocks of plants and trees: photosynthesis. Given the intense international focus on greenhouse gases over the past decade, it is unsurprising that many chemists are trying to find routes to useful products. The challenge, as with much of chemistry, is to find synthetic catalysts that speed up reactions in a way that is as good as nature or better.

Liquid Light, a spinout from Princeton University, uses electricity and catalysts (what they are is a secret), to make chemicals from carbon dioxide, and seems to have progressed to having a near-commercial process to make ethylene glycol, a key component of anti-freeze and, more interestingly, a building block of polyester bottles and fibres. Scientists at Liquid Light believe they can tailor their catalysts to make other chemicals, and that the electricity used can come from solar panels. The company takes photosynthesis-level efficiency as the benchmark against which to measure their process, and claims it is now twice as efficient.

A German chemical company, BASF, and a US company, Novomer, are capturing CO2 from power plants or other waste sources, using novel catalysts to make polypropylene carbonate. This plastic can be used for coatings, adhesives, foams and packaging and can replace other plastics in these applications that are currently made from oil. Both companies are moving towards commercial processes. Bayer, another large German chemical company, is also advancing a process to make polyurethane foams using carbon dioxide.

A more brute force approach is that taken by the Solar Jet programme in Switzerland, led by Dr Aldo Steinfeld of ETH-Zurichcollaborating with Shell. They designed a clever reactor that generates very high temperatures from solar energy to break down carbon dioxide and water, converting them to hydrogen and carbon monoxide. From this mixture they can make kerosene for jet fuel using well-known chemical processes. This is still at an early stage – so far they have made one litre of fuel – but sometimes these high temperature processes are more straightforward to scale up than catalyst-based approaches.

Carbon dioxide utilisation is attracting clever chemists and engineers, start-up venture capital and big established players. This is an area to watch for one or more revolutions of the chemical industry in the next five years.

Turning carbon dioxide emissions into chemicals, fibers and jet fuel

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Friday, August 1, 2014

Security threats with USB


We all rely on USB to interconnect our digital lives, but new research first reported by Wired reveals that there's a fundamental security flaw in the very way that the humble Universal Serial Bus functions, and it could be exploited to wreak havoc on any computer.
Wired reports that security researchers Karsten Nohl and Jakob Lell have reverse engineered the firmware that controls the basic communication functions of USB. Not only that, the've also written a piece of malware, called BadUSB, that can "be installed on a USB device to completely take over a PC, invisibly alter files installed from the memory stick, or even redirect the user's internet traffic."
Embedded within USB devices—from thumb drives thorough keyboards to smartphones—is a controller chip which allows the device and a computer it's connected to send information back and forth. It's this that Nohl and Lell have targeted, which means their malware doesn't sit in flash memory, but rather is hidden away in firmware, undeletable by all but the most technically knowledgable. Lell explained to Wired:
"You can give it to your IT security people, they scan it, delete some files, and give it back to you telling you it's 'clean... [But these] problems can't be patched. We're exploiting the very way that USB is designed."

The kicker is that it's virtually impossible to check whether a device's firmware has been tampered with, and even if it was, there's no single trusted version of it to check against. It's also worth pointing out that it can travel both ways: a USB stick could infect a computer with its malware, say, and the PC could then infect any USB device plugged into it.
So it's fairly worrying that the pair of researchers have demonstrated—and will present at the upcoming Black Hat security conference in Las Vegas—that the flaw can be exploited on thumb drives, mice, keyboards and even an Android smartphone. (It should, in theory, work on any USB device that can have its firmware reprogrammed).Some of Wired's sources even speculate that the hack could already be being used by the NSA.
That's a lot of bad news—so what can you do about it? Technically speaking, very little: there's no patch of code that can be be used to solve the problem. Instead, both the USB Implementers Forum and the researcherspoint out that a change in the way we use USB is the only solution: don't plug a USB device into any computer you don't 100 percent trust, and don't plug untrusted USB device into your computer either. That may prove inconvenient—but it may also save you from a very nasty surprise, too. [Wired

USB Has a Fundamental Security Flaw That You Can't Detect

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Thursday, July 31, 2014

A Real Artificial Leaf Made By Man

RCA graduate Julian Melchiorri says the synthetic biological leaf he developed, which absorbs water and carbon dioxide to produce oxygen just like a plant, could enable long-distance space travel.


Silk Leaf by Julian Melchiorri

"Plants don't grow in zero gravity," explainsMelchiorri. "NASA is researching different ways to produce oxygen for long-distance space journeys to let us live in space. This material could allow us t0 explore space much further than we can now."

Melchiorri's Silk Leaf project, which he developed as part of the Royal College of Art's Innovation Design Engineering course in collaboration with Tufts University silk lab, consists of chloroplasts suspended in a matrix made out of silk protein.
Chloroplasts

"The material is extracted directly from the fibres of silk," Melchiorri explains. "This material has an amazing property of stabilising molecules. I extracted chloroplasts from plant cells and placed them inside this silk protein. As an outcome I have the first photosynthetic material that is living and breathing as a leaf does."


Chloroplasts suspended in silk protein
Like the leaves of a plant, all Melchiorri's Silk Leaf needs to produce oxygen is light and a small amount of water.
Silk Leaf lamps by Julian Melchiorri
"Silk Leaf is the first man-made biological leaf," he claims. "It's very light, low energy-consuming, it's completely biological."

Photosynthetic Facade

Visualisation of a photosynthetic facade by Julian Melchiorri
"My idea was to use the efficiency of nature in a man-made environment," he explained. "I created some lighting out of this material, using the light to illuminate the house but at the same time to create oxygen for us."

Photosynthetic Filters For Buildings

Visualisation of photosynthetic filters for buildings by Julian Melchiorri
However, Melchiorri says the material could also be used at a much larger scale.
"It could [also] be used for outdoor applications," he says. "So facades, ventilation systems. You can absorb air from outside, pass it through these biological filters and then bring oxygenated air inside."

The first man-made biological leaf could enable humans to colonise space

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Monday, July 28, 2014

Babies’ brains practice words long before they can speaks

A one-year-old sits in a brain scanner while researchers record her brain responses to spoken syllables. 
  
Newborn babies arrive as strangers in a strange land. They know nothing of the customs or language of their new mysterious world. Yet astonishingly, with almost no obvious effort, babies learn an entirely new language. Some babies even learn several.
They manage this feat, in part, by tons of behind-the-scenes practice, a new study finds. Babies mentally rehearse the movements required for speech long before they utter a word, scientists reported July 14 in the Proceedings of the National Academy of Sciences.
This result might explain why babies sometimes get those super intense, slightly confused looks when you’re talking to them, kind of like Zoolander’s Blue Steel. Maybe babies are concentrating really hard, trying to figure out exactly how your mouth is able to produce those funny noises.
Scientists led by Patricia Kuhl of the Institute for Learning and Brain Sciences at the University of Washington, Seattle tested the responses of babies’ brains as they listened to spoken syllables. The team used a technique called magnetoencephalography, which measures subtle magnetic differences caused by differences in brain activity, to figure out which brain areas are active when babies hear syllables.
Unlike other brain scanning methods, a little bit of motion is OK with MEG, making the technique great for little kids. (University of Washington lab member Sarah Roseberry Lytle says that the lab keeps a professional toy-shaker around for the sole purpose of taming wiggly babies during their scans.)
Syllables of speech mesmerize this baby while scientists figure out which parts of the brain are active.
In 7-month-old babies, brain areas important for movement and hearing were active as the babies heard a familiar syllable. “It’s almost as if their brain is rehearsing,” says Lytle, who directs the outreach division of the Institute for Learning and Brain Sciences and wasn’t involved in the study.
In slightly older babies, the brain behaved differently: Auditory areas were very involved, while motor areas seemed to play less of a role. This weakened motor area response in 11-month-old babies, and also in adult listeners, might indicate a baby’s familiarity with the sound.
By 11 months, the syllable has become a familiar one, and the motor areas of the brain might not need to work as hard mimicking the movement. This idea fits with what happened when the older babies heard a syllable that doesn’t exist in their native language. All of a sudden, those motor areas once again jumped to attention.
This result makes sense, given what scientists know about how babies learn language over time. Babies start off as generalists. These little citizens of the world pick up any and all sounds and languages that happen to float by. But during the second half of their first year, babies get choosier and focus more brainpower on the language spoken most frequently around them. So a new sound might prompt babies to start back at square one and try to figure out how the speaker makes that noise.
Studies like these are starting to MEsome of the mysterious ways in which infant brains soak up language so easily. One day, we might actually know how these precocious little learners pull off their linguistic feats. But just because we understand it a little better won’t make it any less amazing.

Babies’ brains practice words long before they canspeaks

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Thursday, July 24, 2014

Measuring the Planet Size 


Thanks to NASA's Kepler and Spitzer Space Telescopes, scientists have made the most precise measurement ever of the radius of a planet outside our solar system. The size of the exoplanet, dubbed Kepler-93b, is now known to an uncertainty of just 74 miles (119 kilometers) on either side of the planetary body.
The findings confirm Kepler-93b as a "super-Earth" that is about one-and-a-half times the size of our planet. Although super-Earths are common in the galaxy, none exist in our solar system. Exoplanets like Kepler-93b are therefore our only laboratories to study this major class of planet.
With good limits on the sizes and masses of super-Earths, scientists can finally start to theorize about what makes up these weird worlds. Previous measurements, by the Keck Observatory in Hawaii, had put Kepler-93b's mass at about 3.8 times that of Earth. The density of Kepler-93b, derived from its mass and newly obtained radius, indicates the planet is in fact very likely made of iron and rock, like Earth. 
"With Kepler and Spitzer, we've captured the most precise measurement to date of an alien planet's size, which is critical for understanding these far-off worlds," said Sarah Ballard, a NASA Carl Sagan Fellow at the University of Washington in Seattle and lead author of a paper on the findings published in the Astrophysical Journal.
"The measurement is so precise that it's literally like being able to measure the height of a six-foot tall person to within three quarters of an inch -- if that person were standing on Jupiter," said Ballard.
Kepler-93b orbits a star located about 300 light-years away, with approximately 90 percent of the sun's mass and radius. The exoplanet's orbital distance -- only about one-sixth that of Mercury's from the sun -- implies a scorching surface temperature around 1,400 degrees Fahrenheit (760 degrees Celsius). Despite its newfound similarities in composition to Earth, Kepler-93b is far too hot for life.  
To make the key measurement about this toasty exoplanet's radius, the Kepler and Spitzer telescopes each watched Kepler-93b cross, or transit, the face of its star, eclipsing a tiny portion of starlight. Kepler's unflinching gaze also simultaneously tracked the dimming of the star caused by seismic waves moving within its interior. These readings encode precise information about the star's interior. The team leveraged them to narrowly gauge the star's radius, which is crucial for measuring the planetary radius.
Spitzer, meanwhile, confirmed that the exoplanet's transit looked the same in infrared light as in Kepler's visible-light observations. These corroborating data from Spitzer -- some of which were gathered in a new, precision observing mode -- ruled out the possibility that Kepler's detection of the exoplanet was bogus, or a so-called false positive.
Taken together, the data boast an error bar of just one percent of the radius of Kepler-93b. The measurements mean that the planet, estimated at about 11,700 miles (18,800 kilometers) in diameter, could be bigger or smaller by about 150 miles (240 kilometers), the approximate distance between Washington, D.C., and Philadelphia.
Spitzer racked up a total of seven transits of Kepler-93b between 2010 and 2011. Three of the transits were snapped using a "peak-up" observational technique. In 2011, Spitzer engineers repurposed the spacecraft's peak-up camera, originally used to point the telescope precisely, to control where light lands on individual pixels within Spitzer's infrared camera.
The upshot of this rejiggering: Ballard and her colleagues were able to cut in half the range of uncertainty of the Spitzer measurements of the exoplanet radius, improving the agreement between the Spitzer and Kepler measurements.
"Ballard and her team have made a major scientific advance while demonstrating the power of Spitzer's new approach to exoplanet observations," said Michael Werner, project scientist for the Spitzer Space Telescope at NASA's Jet Propulsion Laboratory, Pasadena, California.
JPL manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Spacecraft operations are based at Lockheed Martin Space Systems Company, Littleton, Colorado. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech. Caltech manages JPL for NASA.
NASA's Ames Research Center in Moffett Field, California, is responsible for Kepler's ground system development, mission operations and science data analysis. JPL managed Kepler mission development. Ball Aerospace & Technologies Corp. in Boulder, Colorado, developed the Kepler flight system and supports mission operations with the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder. The Space Telescope Science Institute in Baltimore archives, hosts and distributes Kepler science data. Kepler is NASA's 10th Discovery Mission and was funded by the agency's Science Mission Directorate.
For more information about the Kepler mission, visit:
For more information about Spitzer, visit:

How to measure a planet

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Wednesday, July 23, 2014

Time to unleash the mozzies? Genetically modified mosquitoes will be raised on a commercial scale for the first time, in a bid to stem outbreaks of dengue fever in Brazil. But it is unclear how well it will work.

Next week biotech company Oxitec of Abingdon, UK, will open a factory in Campinas, Brazil, to raise millions of modified mosquitoes. Once released, they will mate with wild females, whose offspring then die before adulthood. That should cut the number of dengue-carrying Aedes aegypti mosquitoes. In April, Brazil'sNational Technical Commission for Biosecurity(CTNBio) approved their commercial use.

The mosquitoes could be an important step forward in controlling dengue, which affects more than 50 million people every year, with a 30-fold increase in the last 50 years. There is no vaccine or preventive drug, so all anyone can do is to spray insecticide on a large scale in a bid to kill dengue-carrying mosquitoes.

The Brazilian state of Bahia is one of the affected areas. A state of alert, declared in February, is in force in 10 rural districts. Oxitec plans to release millions of modified mosquitoes in the Bahia town of Jacobina, as part of an expanded research programme. A larger release could follow if the Brazilian Health Surveillance Agency also lends its approval, as expected.

Question mark

But no one is sure if the insects will succeed. Margareth Capurro at the University of São Paulo has studied the effects of a trial release in Jacobina last year. She plans to submit her report this month.

Capurro says her data show the number of mosquito eggs falling by an impressive 92 per cent in Jacobina. But so far this has not led to a drop in the incidence of dengue.

That may be because the study was too small, says Capurro. Only after a full epidemiological study next year will we know for sure if the GM mosquitoes are working.

"In every trial we've demonstrated excellent control of the dengue mosquito in an urban setting," says Hadyn Parry of Oxitec. For now they are only measuring success in terms of mosquito numbers.

Dangerous precedent

The CTNBio set a dangerous precedent by approving the commercial release of the mosquitoes before full epidemiological studies had been completed, says agronomist Leonardo Melgarejo, who works for Brazil's Ministry of Agrarian Development, and economist Antonio Inacio Andrioli of the Regional Northwest University of Rio Grande do Sul in Brazil.

In a technical paper presented before the authorisation of the GM mosquitoes, they argued that they should only be released commercially once the technology had been fully evaluated.

In the long run the modified mosquitoes might be stymied by their high cost, says Thomas Unnasch of the University of South Florida in Tampa. The technology depends on sterile males, who by definition cannot pass on the genetically engineered trait. So Unnasch says it would be necessary to release huge numbers of them year after year, at a cost of millions of dollars.

Nevertheless the US authorities are considering using the mosquitoes in Florida, where dengue is also a serious problem.

Brazil to unleash GM-mosquito swarms to fight dengue

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