The CLOUD experiment is studying whether cosmic rays play a role in cloud formation.
| Issue no. 28, 2011
Published: Aug 26, 2011
| 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
Aug 26, 2011
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|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
Aug 25, 2011
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|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
Aug 22, 2011
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|'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
| BBC News
Aug 23, 2011
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|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
Aug 20, 2011
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|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
Aug 25, 2011
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|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
Aug 24, 2011
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