Categoría: English

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.

For the first time, huge "ameobas" have been spotted in the Mariana Trench, the deepest part of the world’s oceans.

The giants of the deep are so-called xenophyophores, sponge-like animals that—like amoebas—are made of just one cell. They were found during a July research expedition run by the Scripps Institution of Oceanography in La Jolla, California.

The animals are about four inches (ten centimeters) long—among the largest single-celled organisms known to exist.

The creatures were discovered at depths of 6.6 miles (10.6 kilometers). That breaks a previous record for xenophyophores found in the New Hebrides Trench at 4.7 miles (7.6 kilometers).

Xenophyophores represent "one of the few groups of organisms found exclusively in the deep sea," said Lisa Levin, a Scripps oceanographer who studied the expedition’s data.

vía Giant “Amoebas” Found in Deepest Place on Earth.

Discovered in 1901, the Antikythera Mechanism has long been called one of the earliest computers. For years scientists had no idea what it did, ascribing it with almost mystical functionality. Through the use of advanced imaging techniques, we now know that this lump of crusty, corroded brass was actually an astronomical computer that allowed ancient Greeks to predict the passage of the planets.

Watchmaker Hublot has recreated the mechanism using modern techniques and shrunk it down to nearly postage-stamp size. The new watch – a one of a kind – features the full mechanism as historians and scientists understand it along with a standard three-hand tourbillon as well as a date register.

vía Hublot Rebuilds The Famed Antikythera Mechanism | TechCrunch.

Prof Carlos Frenk at Durham University, working with the Virgo Consortium, now has data suggesting that our understanding of the formation and composition of the Universe is incomplete.

These data come from an unlikely source: dwarf galaxies, a "halo" of which surrounds our own Milky Way.

These dwarf galaxies are believed to be mostly made up of dark matter, and contain just a few stars. Their dimness has made them difficult to study in the past.

But the Virgo Consortium has created computer simulations to visualise how the dwarf galaxies formed, using their assumptions about CDM.

The team found that the final results of these simulations did not at all match what we observe. The models showed many more small galaxies in a wide halo around the Milky Way, whereas in reality there are fewer, larger dwarf galaxies.

Prof Frenk explained that there were two "equally disturbing possibilities" for why this is the case.

One idea is that many dwarf galaxies formed as in the simulation, but there were violent supernova explosions during their formation that radically changed the structure of the dwarf galaxy halo.

"If this were the case, it would mean that galaxy formation is a much more exciting process than we thought," said Prof Frenk.

But there are still uncertainties over whether the small fraction of normal matter in the Universe (4%) could have such a fundamental effect on the structure of the dark matter.

An alternative cause for the discrepancies between the modelled data and what we observe is much more fundamental: that CDM does not exist, and the predictions of the standard model relating to it are false.

Prof Frenk said that after working for 35 years with the predictions of the standard model, he is "losing sleep" over the results of the simulations.

vía BBC News – Dwarf galaxies suggest dark matter theory may be wrong.