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Issue no. 19, 2009
Published: Jun 05, 2009 |
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 New radio chip mimics human ear | | Bridging the gap to quantum world | | Robot sub reaches the world's deepest abyss | | Software 'gives children a voice' | | Density triggers cultural explosions | | Text messages can quench plants' thirst | | Doctors see more cases of 'cellphone elbow' | | Artificial sun gives salad its colour back | | Radio-controlled bullets leave no place to hide |
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| New radio chip mimics human ear |
MIT engineers have built a fast, ultra-broadband, low-power radio chip,
modelled on the human inner ear or cochlea, that could enable wireless
devices capable of receiving cell phone, Internet, radio and television
signals. The chip, dubbed the 'radio frequency (RF) cochlea', mimics the
structure and function of the biological cochlea, which uses fluid
mechanics, piezoelectrics and neural signal processing to convert sound
waves into electrical signals that are sent to the brain.
As sound waves enter the cochlea, they create mechanical waves in the
cochlear membrane and the fluid of the inner ear, activating hair cells.
The cochlea can perceive a 100-fold range of frequencies - in humans,
from 100 to 10,000 Hz. The researchers used the same design principles
in the RF cochlea to create a device that can perceive signals at
million-fold higher frequencies, which includes radio signals for most
commercial wireless applications.
The RF cochlea, embedded on a silicon chip measuring 1.5 mm by 3 mm,
works as an antilog spectrum analyzer, detecting the composition of any
electromagnetic waves within its perception range. Electromagnetic waves
travel through electronic inductors and capacitors. Electronic
transistors play the role of the cochlea's hair cells. The analogue RF
cochlea chip is faster than any other RF spectrum analyzer and consumes
about 100 times less power than what would be required for direct
digitization of the entire bandwidth. That makes it desirable as a
component of a universal or 'cognitive' radio, which could receive a
broad range of frequencies and select which ones to attend to. |
| Science Daily / IEEE Journal of Solid-State Circuits
Jun 04, 2009 |
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| Bridging the gap to quantum world |
Scientists at the National Institute for Standards and Technology (Nist)
in the US have 'entangled' the motions of pairs of atoms for the first
time. Entanglement is an effect in quantum mechanics and describes how
properties of two or more objects can be inextricably linked over 'vast'
distances. The results further bridge the gap between the world of
quantum mechanics and the laws of everyday experience.
This is the first time entanglement has been seen in a so-called
'mechanical system'. The phenomenon suggests that a measurement
performed on one object can affect the measurement on another object
some distance away. It also implies that the behaviour of two separate
objects is linked by some unseen connection.
Entanglement could be exploited in future quantum computers, because the
inherent probability-based nature of quantum systems means they can
compute certain kinds of problems significantly more quickly than
current 'classical' computers. |
| BBC News / Nature
Jun 03, 2009 |
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| Robot sub reaches the world's deepest abyss |
A robotic submarine named Nereus has become the third craft in history
to reach the deepest part of the world's oceans, at the bottom of the
Mariana Trench in the western Pacific Ocean. The dive to Challenger
Deep, an abyss within the Mariana Trench that reaches 11,000 metres
beneath the waves, was completed on 31 May by a team from the Woods Hole
Oceanographic Institution (WHOI), Massachussetts, US.
For the expedition, the team had to build a new breed of
remotely-operated submarine, called Nereus, which is capable of going
deeper than any other while still filming and collecting samples.
Sunday's dive makes it the world's deepest-diving vehicle, and the first
vehicle to explore the Mariana Trench since 1998.
Only two other vehicles have ever reached the bottom of Challenger Deep:
US bathyscaphe Trieste, which carried Jacques Piccard and Don Walsh in
1960, and the Japanese robot Kaiko, which made three unmanned
expeditions to the trench between 1995 and 1998. Trieste was retired in
1966, and Kaiko was lost at sea in 2003. |
| New Scientist
Jun 02, 2009 |
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| Software 'gives children a voice' |
Scientists say they have developed the first technology of its kind to
allow children with communication problems to converse better. 'How was
school today?' is software to help children with disabilities such as
cerebral palsy communicate faster. The system is the result of a project
between computing scientists from the Universities of Aberdeen and
Dundee, and Capability Scotland.
For a child with severe motor disabilities and limited or no speech,
holding a conversation is often very difficult and limited to short one
to two word answers. To tell a longer story a communication device is
often needed to form sentences but this can be very time consuming,
putting a lot of strain on holding and controlling the conversation.
The new software uses sensors, swipe cards, and a recording device to
gather information on what the child using the system has experienced at
school that day. This can then be turned into a story by the computer -
using what is called natural language generation - which the pupils can
then share when they get home. The system is designed to support a more
interactive narration, allowing children to easily talk about their
school day and to quickly answer questions, according to the
researchers. |
| BBC News
Jun 04, 2009 |
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| Density triggers cultural explosions |
Increasing population density, rather than boosts in human brain power,
appears to have catalysed the emergence of modern human behaviour,
according to a new study by University College London scientists.
High population density leads to greater exchange of ideas and skills
and prevents the loss of new innovations. It is this skill maintenance,
combined with a greater probability of useful innovations, that led to
modern human behaviour appearing at different times in different parts
of the world.
The team found that complex skills learnt across generations can only be
maintained when there is a critical level of interaction between people.
Using computer simulations of social learning, they showed that high and
low-skilled groups could coexist over long periods of time and that the
degree of skill they maintained depended on local population density or
the degree of migration between them.
Using genetic estimates of population size in the past, the team went on
to show that density was similar in sub-Saharan Africa, Europe and the
Middle-East when modern behaviour first appeared in each of these
regions. The paper also points to evidence that population density would
have dropped for climatic reasons at the time when modern human
behaviour temporarily disappeared in sub-Saharan Africa. |
| ScienceDaily / Science
Jun 05, 2009 |
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| Text messages can quench plants' thirst |
Carrots might not scream when pulled from the ground, but new technology
is giving vegetables a voice in how they are raised. Microchipped plants
can now send text messages to a farmer's cell phone and ask for water.
For areas that receive regular and plentiful rainfall, such detailed
crop monitoring might not be useful or economical. But in the western
United States, where much of the water comes from underground aquifers,
conserving water, and more importantly, conserving the electricity that
pumps it to the surface and across fields, could save farmers hundreds
of thousands of dollars each year.
The original cell phone for plants was developed years ago by scientists
working with NASA on future manned missions to the moon and Mars. To
reduce the amount of time and supplies necessary to grow crops,
scientists clipped sensors, wired to a central computer, to plants so
astronauts would know exactly when and how much water to give them.
During the initial NASA tests the scientists were able to reduce the
amount of water necessary to grow plants by 10% to 40%. |
| MSNBC
May 29, 2009 |
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| Doctors see more cases of 'cellphone elbow' |
As people spend more time gabbing on cellphones, doctors in the US say
they are seeing more cases of numbness, tingling and pain from
'cellphone elbow'. Cubital tunnel syndrome is similar to carpal tunnel
syndrome that causes pain in the hand and wrist, but in this case it is
the ulnar nerve that crosses the inside of the elbow that gets pinched.
Patients with cubital tunnel syndrome often notice numbness inside the
hand in the ring and little finger but symptoms vary between people.
When the ulnar nerve is stretched and tensed for a long time, it will
become irritated and not perform well. Physiotherapy and acupuncture can
settle the inflammation, and shaking and pumping the arm can also help.
If the nerve compression persists, symptoms may worsen to hand fatigue
and weakness, including difficulty opening bottles or jars. In most
cases, lifestyle changes can help prevent or resolve symptoms. |
| CBC News
Jun 03, 2009 |
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| Artificial sun gives salad its colour back |
Unhealthily pale lettuce can make even the best salads look wan and
unsavoury. But a couple of days under weak ultraviolet light before you
pick it can make the lettuce more palatable.
Tests at a US Department of Agriculture (USDA) lab in Maryland show that
an LED radiating just a few milliwatts in the UV-B band stimulates
red-leaf lettuce to make the antioxidants that give it its
characteristic colouring.
Growing crops in greenhouses, done to supply fresh greens all year
round, blocks the UV in sunlight that normally prompts lettuce and other
crops to make antioxidants outdoors. Fluorescent lamps could be used to
provide the missing UV, but that would require vast arrays of lamps
containing mercury, which could contaminate food.
Curious to see if cheap, mercury-free UV LEDs could do the job instead,
researchers suspended one a few centimetres above a red-leaf lettuce
plant. After 48 hours, the leaves were a deep red, but others away from
the UV LED remained green. The team is now trying to work out which
wavelength in the UV-B band does the job best. |
| New Scientist
Jun 03, 2009 |
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| Radio-controlled bullets leave no place to hide |
A rifle capable of firing explosive bullets that can detonate within a
metre of a target could let soldiers fire on snipers hiding in trenches,
behind walls or inside buildings. The US army has developed the XM25
rifle to give its troops an alternative to calling in artillery fire or
air strikes when an enemy has taken cover and can't be targeted by
direct fire.
The rifle's gunsight uses a laser rangefinder to calculate the exact
distance to the obstruction. The soldier can then add or subtract up to
3 metres from that distance to enable the bullets to clear the barrier
and explode above or beside the target.
As the 25-millimetre round is fired, the gunsight sends a radio signal
to a chip inside the bullet, telling it the precise distance to the
target. A spiral groove inside the barrel makes the bullet rotate as it
travels, and as it also contains a magnetic transducer, this rotation
through the Earth's magnetic field generates an alternating current. The
chip uses fluctuations in this current to count each revolution and, as
it knows the distance covered in one spin, it can calculate how far it
has travelled. |
| New Scientist
Jun 04, 2009 |
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