Categoría: ENLACES (links externos)

The MIT team, led by research scientist Chi-Sang Poon, has been able to design a computer chip that can simulate the activity of a single brain synapse.

Activity in the synapses relies on so-called ion channels which control the flow of charged atoms such as sodium, potassium and calcium.

The ‘brain chip’ has about 400 transistors and is wired up to replicate the circuitry of the brain.

Current flows through the transistors in the same way as ions flow through ion channels in a brain cell.

"We can tweak the parameters of the circuit to match specific ions channels… We now have a way to capture each and every ionic process that’s going on in a neuron," said Mr Poon.

Neurobiologists seem to be impressed.

It represents "a significant advance in the efforts to incorporate what we know about the biology of neurons and synaptic plasticity onto …chips," said Dean Buonomano, a professor of neurobiology at the University of California.

"The level of biological realism is impressive," he added.

The team plans to use their chip to build systems to model specific neural functions, such as visual processing.

Such systems could be much faster than computers which take hours or even days to simulate a brain circuit. The chip could ultimately prove to be even faster than the biological process.

vía BBC News – Scientists at MIT replicate brain activity with chip.

The LHCb detector was designed to examine particles called mesons, watching them decay through time after high-energy collisions of other fundamental particles.

The LHCb Collaboration was looking at decays of particles called D-mesons, which can in turn decay into kaons and pions.

LHCb, one of the six separate experiments at the Large Hadron Collider, is particularly suited for examining what is called "CP violation" – slight differences in behaviour if a given particle is swapped for its antimatter counterpart.

Our best understanding of physics so far, called the Standard Model, suggests that the complicated cascades of decay of matter particles into other particles should be very nearly the same – within less than 0.1% – as a similar chain of antimatter decays.

Other experiments, notably at the Fermi National Accelerator facility in the US, have found a CP violation of about 0.1%, but with an uncertainty in their measurement that meant the result might just fit within the Standard Model.

But the LHCb team is reporting a difference of about 0.8% – a significant difference that, if true, could herald the first "new physics" to be found at the LHC.

"Our result is more significant firstly because it comes out with a [greater difference] and secondly because our precision is improved – somewhat more precise than all of the previous results put together," Dr Charles told BBC News.

Spotting such a difference in the behaviour of matter and antimatter particles may also finally help explain why our Universe is overwhelmingly made of matter.

"Certainly this kind of effect, a new source of CP violation, could be a manifestation of the physics which drives the matter – antimatter asymmetry," Dr Charles explained.

However, he stressed there are "many steps in the chain" between confirming the collaboration’s experimental result, and resolving the theory to accommodate it.

"This result is a hint of something interesting and if it bears out, it will mean that, at a minimum, our current theoretical understanding needs improving," Dr Charles said.

"It’s exactly the sort of thing for which the LHC was originally built."

vía BBC News – LHC reveals hints of ‘new physics’ in particle decays.