Issue no. 4, 2011
Published: Jan 28, 2011 |
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 Computer memory heralds green PCs |
| Physicists create 'backward laser' |
| Scientists develop IQ test for bacteria |
| World's first brain scanner made for two |
| How broccoli fights cancer |
| Compact 'eyeball' camera stretches to zoom |
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| Computer memory heralds green PCs |
A new form of computing memory which could lead to faster starting,
user-friendly computers has been developed by researchers at North
Carolina State University. The 'unified' memory device claims to combine
the advantages of two commons forms of memory used today.
Currently, computers rely on two distinct forms of memory: volatile and
non-volatile. The type of memory used depends on whether data needs to
be accessed quickly or stored permanently. Volatile technologies such as
random access memory (RAM) or its newer variation DRAM, store data in
such a way that it can be read and written rapidly, making it ideal for
rapid computations. But the data is lost when the power is switched off.
Non-volatile memory devices, such as the flash drives, can retain
information for long periods without power, but it is slow.
But the new device combines the speed of DRAM while being able to switch
to a more persistent mode of storage. That would potentially enable
computer makers to build machines that boot up almost instantly, as the
information needed to start up the machine could be stored in fast
memory, the researcher say. It could also lead to servers that can be
powered down, when not in use.
The device known as a double floating-gate field effect transistor -
stores data in the form of a charge, like non-volatile memory but uses a
special control gate to enable the stored data to be accessed quickly.
His team have shown they can transfer charges - in effect change the
data - in around 15 nanoseconds, comparable with DRAM speeds. When in
non-volatile mode, the data will be stored safely for several years. |
| BBC News / IEEE Computer
Jan 25, 2011 |
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| Physicists create 'backward laser' |
A team of physicists in the US has created an infrared laser beam at a
point in mid air, by focusing a UV laser onto a tiny volume of oxygen
molecules. Much of the emergent infrared laser light travels back
towards the UV laser, sampling the intervening air as it returns. As
such, this 'backward laser' could potentially provide measurements of
pollutants and other molecules in environments that would be hard or
impossible to study with conventional laser systems.
There are a number of different ways in which lasers are used to measure
the concentration of particular gases in the air, be it pollutants in
the atmosphere or the trace gases given off by solid explosives. But
existing methods are difficult to use in enclosed or remote
environments, or calls for a very powerful lasers.
But now researchers at Princeton University used a different mechanism
to set up mid-air lasing. By focusing a 226 nm wavelength laser beam
onto a tiny volume of air at a distance of between 30 cm and 1 m, they
were able to break down oxygen molecules into their constituent atoms
and then excite these atoms. Getting these atoms to lase then relied on
two crucial properties of the beam's focus. Being very high intensity,
this focus induces a population inversion in the oxygen atoms, ensuring
that there are more excited than non-excited atoms.
In addition to this, the shape of the focus - being about a millimetre
long and just a hundredth of a millimetre wide - means that any atoms
undergoing spontaneous emission tend to stimulate emission in other
excited atoms either in the forward or backward directions, rather than
at some arbitrary angle to the beam. This leads to high gain in both
forward and backward directions. |
| PhysicsWorld / Science
Jan 27, 2011 |
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| Scientists develop IQ test for bacteria |
IQ scores are used to assess the intelligence of human beings. Now Tel
Aviv University has developed a 'Social-IQ score' for bacteria - and it
may lead to new antibiotics and powerful bacteria-based 'green'
pesticides for the agricultural industry.
The researchers looked at genes which allow the bacteria to communicate
and process information about their environment, making decisions and
synthesising agents for defensive and offensive purposes. This research
shows that bacteria are not simple solitary organisms, or 'low level'
entities, as earlier believed - but are highly social and evolved
creatures. They consistently foil the medical community as they
constantly develop strategies against the latest antibiotics.
The study shows that everyday pathogenic bacteria are not so smart -
their S-IQ score is just at the average level. But the social
intelligence of the pattern-forming Paenibacillus vortex (Vortex)
bacteria is at the 'genius range'. Armed with this kind of information
on the social intelligence of bacteria, researchers will be better able
to outsmart them, the researcher say.
This information can also be directly applied in 'green' agriculture or
biological control, where bacteria's advanced offense strategies and
toxic agents can be used to fight harmful bacteria, fungi and even
higher organisms. Knowing the Social-IQ score could help developers
determine which bacteria are the most efficient. |
| PhysOrg / BMC Genomics
Jan 24, 2011 |
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| World's first brain scanner made for two |
Two heads are better than one - particularly if you are studying the
brain activity underlying social interaction. The problem is that
imaging technologies such as MRI have only been able to handle one brain
at a time - until now. Ray Lee at Princeton University has developed
dual-headed fMRI scanner. The innovation allows the simultaneous imaging
of the brain activity of two people lying in the same scanner.
Usually, a lone person lies inside a scanner's narrow tunnel, cocooned
by powerful magnets and radio-frequency coils which detect how hydrogen
atoms in the body respond to magnetic fields, or how the flow of
oxygenated blood changes as a result of brain activity. Although it is
possible to squeeze two adults into most MRI machines, attempting to
scan both their brains at once would produce too fuzzy an image.
So Lee designed a pair of coils that fits into a scanner, providing two
distinct loops in which to place each participant's head. He also fitted
a window between the coils so participants can see one another.
To test the scanner, Lee asked couples to lie facing one another and
blink in unison. Brain activity in the fusiform gyrus - involved in
facial recognition - was tightly correlated. Lee also asked couples to
repeatedly embrace and release one another, and observed similarly
synchronised brain activity. |
| New Scientist
Jan 27, 2011 |
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| How broccoli fights cancer |
Generations of children have been told, 'Eat your broccoli!'. And for
decades, researchers have known that broccoli and related vegetables
like cauliflower and watercress appeared to lower the risk of some
cancers. And that compounds in the vegetables could kill cancer cells.
But how the cruciferous vegetables did that was a mystery. Until now.
Proteins coded by the gene p53 help keep cancer from starting to grow.
But when the p53 gene is mutated, the protection is gone. Mutated p53 is
implicated in about half of all human cancers. Broccoli and its
relatives are rich in compounds called isothiocyanates, or ITCs. And
these ITCs apparently destroy the products of the mutant p53 gene, but
leave the healthy p53 proteins alone and free to suppress tumour
development.
The researchers from Georgetown University in the US write that
depletion of mutant p53 may reduce drug resistance and lead to new
strategies for treating cancer in the clinic. |
| Scientific American / Journal of Medicinal Chemistry
Jan 27, 2011 |
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| Compact 'eyeball' camera stretches to zoom |
A camera inspired by the operation of the human eye can 'zoom' without
the need for bulky lenses, making it more compact than conventional
cameras. The device has a stretchable lens and a flexible photodetector
whose shape alters as the magnification of the lens changes. This
produces a camera with a 3.5× optical zoom.
Traditional cameras capture their images on a flat surface, usually a
digital photodetector. In a conventional camera, extra lenses are
required to flatten the image before it hits the detector, otherwise it
appears blurry or uneven. The eyeball camera does away with the need for
these extra, movable lenses, and reshapes the sensor instead. Rather
than adjusting the image to suit a flat surface, it flexes the sensor to
match the curvature of the image and the lens.
To achieve this, Rogers has mounted an array of silicon photodetectors
on an elastic membrane, which in turn forms the surface of a fluid-
filled chamber. Using hydraulic actuators to adjust the amount of fluid
in the chamber, the membrane can be flexed to take up convex or concave
shapes. The lens is formed by fluid held in a gap between a glass window
and an elastic membrane whose shape can also be adjusted hydraulically.
The eyeball technology could be used in night-vision cameras that now
typically use bulky and expensive lenses to capture infrared images.
Another application would be endoscopes, where very tiny cameras with a
wide field of view are required, Rogers says. |
| New Scientist / Proceedings of the National Academy of Sciences
Jan 27, 2011 |
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