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This week's headlines:
	Cosmic ray climate theory put to the test at CERN
	Bacteria stops dengue in tracks
	Acoustic monitoring predicts dangerous solar flares
	'Smart' CCTV could track rioters
	Coffee stain helps smarter inks
	Cars could run on recycled newspaper, scientists say
	Mobile phones could soon be 'powered by walking'
Cosmic ray climate theory put to the test at CERN
Clouds are formed by the condensation of water vapour in the atmosphere around clusters of molecules such as ammonia and sulphuric acid. Ions created by the passage of cosmic rays can trigger the formation of such molecular seeds - a process of particular interest because the arrival of cosmic rays is regulated, in part, by the sun. The 11-year solar cycle changes the sun's magnetic field. That, in turn, affects the passage of cosmic rays and thus the number of such rays that make it to Earth. Since clouds help regulate the climate, by reflecting sunlight back into space and cooling the atmosphere, some scientists think cosmic rays are a means by which changes in solar activity are translated into terrestrial climate change. In order to investigate how much cosmic rays affect cloud formation a team at CERN recreated both the solar cycle and the atmosphere in a lab. Their 'cosmic rays' are generated by a particle accelerators. To simulate the atmosphere, they have built a special cloud chamber with the air manufactured from scratch, using liquid nitrogen and oxygen together with precise amounts of trace compounds, including sulphuric acid and ammonia. By comparing rates of seed formation during the different phases of the experiments, the researchers were able to put a figure on cosmic rays' contribution to the process. The results suggest naturally occurring rays enhance seed-formation rates by a factor of ten. That implies the rays' varying intensity could indeed affect the climate. The team remain cautious, however, because they also discovered that the seed-formation rates for sulphuric acid and ammonia are between a tenth and a thousandth of those needed to account for the cloud seeding actually seen in the atmosphere. That suggests other compounds are important too and current climate models, which assume most seeds are made of ammonia or sulphuric acid, may require revision.
The Economist / Nature    August 26, 2011 back to top
Bacteria stops dengue in tracks
Australian scientists say they have discovered a cheap and effective method of preventing the transmission of dengue fever, which affects more than 50 million people worldwide every year. According to the World Health Organization around one third of the world's population is at risk from dengue fever. The incidence and severity of this untreatable, mosquito-borne illness are increasing in many parts of the world. Pesticides that kill the specific type of mosquitoes that carry the virus have been the most effective method of control to date, but resistance is rising. Now a team of Australian scientists say that a simple bacterium called Wolbachia that only infects insects could stop dengue in its tracks. They infected mosquitoes that spread the disease with Wolbachia which blocks transmission of the dengue virus. When the resistant insects were released, they successfully interbred with wild mosquitoes and halted their ability to transmit dengue. The researchers are hopeful that this could be a viable control for the disease. After a series of laboratory experiments that proved the power of Wolbachia to restrict the abilities of mosquitoes to transmit dengue, the scientists then released several hundred thousand of them in Queensland in northeastern Australia. Within months, a wave of infection by the bacterium had spread to almost all the wild mosquitoes rendering them incapable of passing on dengue.
BBC News / Nature    August 25, 2011 back to top
Acoustic monitoring predicts dangerous solar flares
Predicting solar flares is going to become increasingly important as the sun hits the most active phase of its 11-year cycle. Flares can disrupt communication systems, air travel, power grids and satellites, and can also endanger astronauts in space. Now, Stanford researchers have found a way to use acoustic waves to catch sunspots, the precursors to flares, in the early stages of development. The method gives scientists, for the first time, as much as two days' warning. The key is the acoustic waves that are generated inside the sun by the turbulent motion of plasma and gases. Near the surface, small-scale convection cells generate sound waves that travel to the interior of the sun and are refracted back to the surface. The team used data from the Michelson Doppler Imager aboard NASA's SOHO satellite and its replacement, the Solar Dynamics Observatory satellite, which carries the Helioseismic and Magnetic Imager. They were able to develop a way to reduce the electronic clutter in the data so he could accurately measure the solar sounds. This allows sunspots to be detected in the early stages of formation, as deep as 65,000 kilometres inside the sun. Between one and two days later, the sunspots appear on the surface.
TG Daily    August 22, 2011 back to top
'Smart' CCTV could track rioters
CCTV that can automatically monitor criminal behaviour and track suspects is being developed by scientists at Kingston University who have created a system that uses artificial intelligence to recognise specific types of behaviour, such as someone holding a gun. The technology is capable of following a person across multiple cameras. Privacy campaigners warned that it might be used to target groups such as political protesters. However, the developers insisted that their invention would allow police to focus on law breakers and erase images of innocent civilians. The technology works by teaching a computer to recognise specific types of public behaviour, known as 'trigger events'. When an event is triggered, the software collates video footage from before and after the incident to record a full history of the suspect's movements. The study is part of the ADDPRIV project, a European collaboration to build a surveillance solution that acknowledges wider privacy concerns. A key element of the system is the automatic deletion of surplus video data.
BBC News    August 23, 2011 back to top
Coffee stain helps smarter inks
Ever noticed that if you spill coffee onto a table and let it dry, the colour will be concentrated at the edges of the stain? The intriguing phenomenon has been put under the microscope by scientists from the University of Pennsylvania who believe their findings may encourage a revolution in printing, paints and product coatings. The 'coffee-ring effect', they report, derives from two factors: the shape of the particles in the liquid and the way these particles respond to surface tension. 'Particles' mean the molecules of coffee, ink or dye or whatever that are in suspension in the liquid. Round particles tend to gather at the perimeter of the drop, which explains why they remain in a ring once it has dried, according to the research. But particles that are elongated or ellipsoid distribute themselves in looser clumps, which makes it easier to smooth them across the entire surface. The team say their work gives them a new idea about how to make a uniform coating, relatively simply. By changing the particle shape, the way a particle is deposited can be changed and also mixtures can be made. In some cases, even just a small amount of ellipsoids can change the way the particles deposit when they dry.
The Independent / AFP / Nature    August 20, 2011 back to top
Cars could run on recycled newspaper, scientists say
Scientists from Tulane University in the US have discovered a novel bacterial strain, dubbed 'TU-103', that can use paper to produce butanol, a biofuel that can serve as a substitute for gasoline. TU-103 is the first bacterial strain from nature that produces butanol directly from cellulose, an organic compound. The team first identified TU-103 in animal droppings, cultivated it and developed a method for using it to produce butanol. The researchers say that TU-103 is the only known butanol-producing clostridial strain that can grow and produce butanol in the presence of oxygen, which kills other butanol-producing bacteria. Having to produce butanol in an oxygen-free space increases the costs of production. As a biofuel, butanol is superior to ethanol because it can readily fuel existing motor vehicles without any modifications to the engine, can be transported through existing fuel pipelines, is less corrosive, and contains more energy than ethanol, which would improve mileage.
PhysOrg / Tulane University    August 25, 2011 back to top
Mobile phones could soon be 'powered by walking'
Taking a stroll may soon be enough to re-charge your mobile phone, after researchers from the University of Wisconsin developed a way to generate electricity from human motion. The new mechanism uses a principle known as 'reverse electrowetting' - converting the energy of moving microscopic liquid droplets into an electrical current. Once placed in a shoe, the device - which consists of thousands of these electrically conductive droplets - is able to generate electrical energy. There is enough power, according to the researchers, to charge a standard mobile phone or laptop. Getting the energy from the device to the handset presents another challenge. One way is to plug a USB cable into the shoe. A more sophisticated solution suggested by the team is to have the electricity-generating device connected to a shoe-bound wireless transmitter. This would take care of the power hungry part of a mobile phone's job - making radio contact with remote base stations. Signals could be passed between the unit and the user's handset by more efficient short-range systems such as bluetooth or wifi. The team now aim to commercialise their technology.
BBC News / Nature Communications    August 24, 2011 back to top