Friday, August 12, 2011


 How the brain plans, executes movement to a go signalA team of scientists led by Indian-origin electrical engineers has shed new light on how the brain plans for and executes movements in reaction to a "go" signal.
"This research holds great promise in many areas of neuroscience, in particular human prostheses that can be controlled by the brain,” said Krishna Shenoy, who led the study with Maneesh Sahani, both electrical engineers at the Stanford School of Engineering.
The existing hypothesis, known as “rise-to-threshold,” held that in anticipation of a “go” cue, our brains begin to plan the motions necessary to satisfactorily complete the movement by simply increasing the activity of neurons.
Neurons begin to fire, but not enough to cause the movement to take place.
Upon the “go” signal, the brain accelerates this neural firing until it crosses a “threshold” initiating the motion. According to the theory, the longer a preparatory period one has, the greater the neural activity will be and, thus, the faster the reaction time.
But the Stanford team was able to document a process based less on the amount of activity and more on the trajectory of the neural activity through the brain.
Brain of a four-week old human embryo.
In graphs of neural activity prior to display of the target, the study monkeys' neural activity appears somewhat scattered. The moment a target is displayed, however, the neural activity concentrates in an activity region that the researchers dubbed the “optimal sub-space.”
“We can watch as the pattern of neural activity gets focused in a specific region at the moment the target appears, and then when the ‘go’ cue is given, the activity moves again, ending with the successful touching of the target,” explained Shenoy.
The key to reaction time, the researchers found, is the relationship between where the neural activity is and its speed along the ideal trajectory just prior to the go cue.
If the neural activity is closer to the final destination, then the reaction time will be shorter; if farther away, then longer.
From this new understanding, the researchers were able to shape a deeper understanding of the neural patterns and craft a model to predict reaction time.
Recreated :File:Neuron-no labels2.png in Inksc...
"Our model allows us to predict with four times greater accuracy what the reaction time of any single arm motion is going to be based on the neural activity observed prior to movement,” added Sahani.
The findings were recently published in the journal Neuron.

Enhanced by Zemanta

Climate change: cloudy, with a chance of competing realities
There's a quote attributed to Daniel Patrick Moynihan, which generally goes "Everyone is entitled to his own opinion, but not his own facts." Yet that's exactly what seems to have developed in the world of climate science. Within the mainstream scientific community, the basic physics that drives greenhouse warming hasn't been in dispute since it was discovered over a century ago, and the ability of greenhouse gasses to force climate change is apparent on other planets and within the Earth's past.
But there's an entire parallel community, one with a handful of its own scientists. There, any prediction of a measurable impact of climate change is considered unjustifiable alarmism; mainstream science is seen as colluding to stifle all countervailing evidence, as demonstrated by the e-mails stolen from the CRU. (The multiple inquiries that have cleared the scientists who sent the e-mails? Under this view, they're little more than a whitewash.)
How have two communities ended up with what are essentially different facts? It's easy to understand some of the psychology behind it, as behavior that lets us selectively accept information based on things like our group identity has been studied extensively. But many of the differences go well beyond selective filtering. They seem to arise from an entirely separate collection of raw information.

A fatal blow?

A good example of how this sort of thing happens occurred last week. It started with the journal Remote Sensing, which recently published a paper by Roy Spencer, a former NASA scientist who is now based at the University of Alabama, Huntsville. Spencer's specialty is working with satellite data, but he's most notable as a prominent contrarian voice: he tends to ascribe the recent warming trends to factors other than greenhouse gasses.
This stance has made him quite popular within the community that labels itself "skeptics," and has led to a long relationship with a libertarian think tank called the Heartland Institute. That relationship has helped put Spencer on numerous news programs, and sent him to press conferences during major climate summits.
Roy Spencer
Spencer has written, "I would wager that my job has helped save our economy from the economic ravages of out-of-control environmental extremism," suggesting the boundary between his research and advocacy can be a bit blurred. But the mechanisms he uses to explain the earth's warming—he appears to view cloud cover as a forcing rather than a feedback—aren't widely accepted among the broader scientific community. In fact, his ideas have proven so unpopular within the scientific community that he has taken to advancing them via popular books instead of through scientific papers.
But Spencer apparently decided to give peer review another shot. His new paper suggests that, at least in the short term, some of the climate models in common usage overestimate the amount of heat that's trapped in the atmosphere by greenhouse gasses. That result was amplified by aUniversity of Alabama press release, which was picked up by a number of blogs and later entered the mainstream media.
Perhaps the most significant coverage of the paper came at Forbes, which ran an online op-ed that was picked up by Yahoo News. The piece was penned by one of Spencer's colleagues at the Heartland Institute; its headline claimed that "New NASA Data Blow Gaping Hole In Global Warming Alarmism." Filled with dismissals of climate "alarmists," the editorial claims that the paper "should dramatically alter the global warming debate" because it shows that the climate models used by the IPCC are terminally biased towards exaggerating warming. Similar claims were apparently made ahead of Spencer's appearance on several talk shows.
If a person was exposed only to the claims being made in these outlets, it would be easy to conclude that Spencer had struck a blow, perhaps a fatal one, against the mainstream view of the climate.

Meanwhile, in the alternate reality...

The funny thing is that the paper says nothing of the sort. To begin with, it focuses on relatively short-term responses (under two years) to weather events, so its relevance to the long-term forecasts of climate isn't exactly clear, and isn't discussed in the paper. And, at least as far as the general trends, the satellite readings and climate models generally agree; Spencer's paper concludes that the climate's "behavior is also seen in the IPCC AR4 climate models."
There are differences, however, when the models are compared with satellite data in an attempt to determine the relative importance of climate forcings and feedbacks, but the paper interprets this cautiously: "While this discrepancy is nominally in the direction of lower climate sensitivity of the real climate system, there are a variety of parameters other than feedback affecting the lag regression statistics which make accurate feedback diagnosis difficult."
Spencer clearly considers this paper to support his larger contention—that clouds drive climate changes, rather than largely being a response to them—but he does not argue for it forcefully in the paper.
Depending on where people do their reading, it's possible for them to occupy two entirely separate scientific realities.
That caution was already slipping away in the press release, however, which claims that "Earth's atmosphere is apparently more efficient at releasing energy to space than models used to forecast climate change have been programmed to 'believe.'" Still, Spencer himself is quoted as saying that the system is too complex to allow the accurate separation between forcings and feedbacks, a conclusion in keeping with the one in his paper.
But even that limited conclusion hasn't been well received by mainstream scientists. Live Science contacted a number of people who are familiar with climate modeling, and they clearly don't think much of the research. In general, they found the simple model that Spencer uses in order to try to separate out forcings from feedbacks so overly simplified that it's unlikely to provide us with any valuable information. And they point out that short-term differences seen here might not accurately reflect the long-term changes that are the domain of the IPCC model projections. (One of the scientists contacted, Andy Dessler, has even published on the topic and shown that the models that get short-term cloud feedbacks right differ significantly in projecting long-term feedbacks.)
One of the scientists quoted has even performed a quick reanalysis of the data in the paper, which suggested that the accuracy of a model in Spencer's analysis is largely dependent upon the model's ability to handle the El Niño-Southern Oscillation, a short-term climate event.
Those who either looked in detail at the publication or tracked the online response to it might therefore come away with a completely different impression of what the paper said, and what it meant for the field as a whole. In short, it's not simply a matter of an audience selectively picking information; depending on where people do their reading, it's possible for them to occupy two entirely separate scientific realities. In one, the consensus view of greenhouse-driven climate change remains strong, while in the other, Spencer's paper joins a long list of results casting doubt on the conclusions of the IPCC.

Polarization

This has a way of being self-reinforcing. The climate community as a whole will continue to use these climate models because they've concluded that Spencer's paper really doesn't say anything significant about them.
To climate change critics, however, the continued use of existing models appear increasingly delusional, which will undoubtedly feed into some of the more extreme conspiracy theories that have sprung up regarding climate science. The fact that the mainstream press has largely ignored Spencer's paper won't be viewed as a sign that it was limited in its significance; instead, it will be viewed as a sign that the media's bias keeps it from covering any of the material that the self-labelled skeptics say indicates severe problems with climate science (something Ars has been accused of with regularity).
In the end, the availability of a completely alternate framework to interpret the field makes bridging the gaps in understanding between the two sides challenging. Most of the proposed solutions for increasing the public's literacy when it comes to climate change—primarily better education and outreach by a diverse community of scientists—don't really address the level of mistrust and misunderstanding that has piled up over the years.

Enhanced by Zemanta

Found: Planet that's blacker than coal

Artist's conception of the planet TrES-2b (D Aguilar)

A planet orbiting a distant star is darker than coal, reflecting less than 1% of the sunlight falling on it, according to a paper published on Thursday.
The strange world, TrES-2b, is a gas giant the size of Jupiter, rather than a solid, rocky body like Earth or Mars, astronomers said.
It closely orbits the star GSC 03549-02811, located about 750 light years away in the direction of the constellation of Draco the Dragon. "TrES-2b is considerably less reflective than black acrylic paint, so it's truly an alien world," David Kipping of the Harvard-Smithsonian Center for Astrophysics said.
A dark alien world, blacker than coal, has been spotted by astronomers.
The Jupiter-sized planet is orbiting its star at a distance of just five million km, and is likely to be at a temperature of some 1200C.
The planet may be too hot to support reflective clouds like those we see in our own Solar System, but even that would not explain why it is so dark.
The planet, called TrES-2b, is so named because is was first spotted by the Trans-Atlantic Exoplanet Survey in 2006. It is about 750 light-years away, in the Draco constellation.
It also lies in the field of view of the Kepler space telescope, whose primary mission is to spot exoplanets using extremely sensitive brightness measurements as far-flung worlds pass in front of their host stars.
Using the first four months' worth of data from Kepler, David Kipping of the Center for Astrophysics at Harvard University and David Spiegel from Princeton University, looked at the amount of light coming directly from TrES-2b itself.
They measured the amount of light coming from the planet's "night side" - when it is directly in front of its star. They compared that to the light coming from its "day side", just before it passes behind its star and Kepler sees it bathed in light.
The difference between the two gives a measure of how much light the planet reflects - or its albedo.
In our Solar System, clouds on Jupiter give it an albedo of 52%; Earth's is about 37%. But it appears that TrES-2b reflects less than 1% of its star's light.
"This albedo is darker than that of black acrylic paint or coal - it's weird," Dr Kipping told BBC News.
'Exotic chemistry'
The explanation may simply be that the planet is too hot to support the reflective cloud cover we see in our own Solar System.
However, both Dr Kipping and Dr Spiegel said even that would not explain why TrES-2b is such a dark world. It is not just that the planet is failing to reflect light; something must be absorbing it.


Infographic (BBC)

THE KEPLER SPACE TELESCOPE

  • Stares fixedly at a patch corresponding to 1/400th of the sky
  • Looks at more than 150,000 stars
  • In just four months of observations has found 1,235 candidate planets
  • Among them, it has spotted the first definitively rocky exoplanet
  • It has found 68 Earth-sized planets, five of which are in the "habitable zone"

"Chemicals such as gaseous sodium and titanium oxide have been proposed to have this effect," Dr Kipping told BBC News. "Whilst it is possible that there is a huge overabundance of these chemicals, it is probably more likely that there is some exotic chemistry going on which we have never seen before."
Jonathan Fortney, an exoplanetary scientist at the University of California, Santa Cruz, called the work "a nice paper" because "Kepler is allowing us to see these tiny signals from 'hot Jupiters'".
A large fraction of the planets that have been identified in other solar systems are these "hot Jupiters", but little is yet known about them other than their size and proximity to their host stars.
"What will be very interesting is the detection of hot Jupiter reflectivities for different planetary temperature and surface gravities, because that will tell us what planets can keep clouds suspended and what the cloud material might be," Dr Fortney told BBC News.
Much more of the story will be laid bare when more data from the Kepler telescope is put to the test, and when more is released, said Dave Latham, a co-investigator on the Kepler project.
"There are much better data now, from more than two years on orbit, but not yet released to the public," Dr Latham told BBC News.
"A batch of new and higher-quality data is scheduled for release on 22 September. That should allow an improved detection of the (reflectivity of) TrES-2."

Enhanced by Zemanta


GALAXY  S II_3.jpg
The Samsung Galaxy S II is widely believed to be the only real competition to the Apple iPhone. And you can't get it -- yet.

Samsung's mobile division has finally announced a date for the release of its hotly anticipated phone, which has sold lavishly in foreign markets. Over 5 million people worldwide have already bought the flagship Android phone
 in the 85 days it has been on the market -- that's one sold every 1.5 seconds, the company said.

And like Eddie Murphy, it's finally coming to America.Samsung sent an invitation to journalists early Friday touting "a major product announcement" for Aug. 29. The brief note doesn't mention the Galaxy S II by name, but the star-field background and the Roman numeral two clearly suggest what analysts and enthusiasts alike are saying: The Galaxy is coming.

"It isn't rocket science to understand that it's the Galaxy S II announcement," joked Sasha Segan, lead mobile analyst for PCMag.com. Indeed, the name of an image embedded in the announcement speaks for itself, confirming the information the email itself skirts around: Galaxy_S_II_Invite_v2.jpg.

It isn't an understatement to say that the Samsung Galaxy S II is the strongest competition the iPhone faces.
The phone sports a 4.3-inch, 800x480 screen, a 1.2-GHz processor, fast 4G network connectivity, and a sleek, simple design evocative of the iPhone. By contrast, the Apple iPhone 4  has a 3.5-inch, 960x640 screen, a 1-GHz processor, and a slower, 3G connection.

Bigger and faster? Yes, please.

Though it hasn’t gone on sale yet in the U.S., worldwide sales of the Galaxy S II are copious -- practically obscene. In 24 days, the company sold 1 million units -- enough to reach past the top of Mt. Everest if stacked on end. The 2 million units sold in 42 days would fill two and a half soccer fields.

That's a lot of smartphone. But it's more than that: It's a lot of good smartphones, Segan said.

"If the U.S. versions are anything like the international versions, these are going to be spectacular smartphones," he told FoxNews.com. Segan gave an international version of the phone an Editors' Choice award, calling it the finest Android smartphone available today.

The unannounced Apple iPhone 5 is the elephant in the room, of course (and by the way, the 3 million Galaxy S II phones sold in just over 50 days are as heavy as 100 elephants). The iPhone 5 is widely expected to be coming out in September, Segan noted.

And getting the right price could make all the difference for Samsung. "They don't want to be more expensive than the iPhone," Segan said.

It's impossible to compare the stats or pricing for any of these yet-to-be-unveiled phones, of course. But that 4G network connection may prove a major difference between the two. 

"Unless Apple has made some sort of secret breakthrough, [the faster LTE network] might make a Verizon iPhone too thick and power-hungry for Apple's demands this year. Apple may skip it for now and wait for smaller and cooler chipsets," Segan noted. 

That faster connection really pays off for anyone surfing a lot of complicated websites or viewing movies over Netflix, he said. 



Enhanced by Zemanta

Details of RIM's first QNX-based "Colt" smartphone leaked

RIM BlackBerry Storm 2 9550
Hot on the heels of Research In Motion's BlackBerry 7 smartphone lineup announcement, technology blog BGR.com has uncovered details of the company's first QNX-based device, a smartphone codenamed the BlackBerry Colt. The BlackBerry Colt will be powered by the same OS as the PlayBook tablet, "which we hope will make RIM competitive in the smartphone industry once again" said BGR.
However, RIM seems to be stumbling further from the front of the smartphone race, even with a bevy of next generation QNX smartphones on its horizon.
"The worst part isn't that the QNX-powered phone won’t be ready until the first quarter of 2012, but that RIM doesn't seem like it has learned from the mistakes from the PlayBook," wrote ZDNet.
According to BGR's tipster, the BlackBerry Colt won't be sporting a uber-fast quad-core or even a dual-core processor on launch. It will have a single core 1 GHz processor which, as ZDNet notes, puts it behind its already launched Android and iOS rivals.
Another complaint is the phone's initial lack of support for BlackBerry Enterprise Server, RIM's corporate email solution.
"If companies want to use Microsoft Exchange email on the device, they will actually have to use Microsoft ActiveSync," said BGR.
One saving grace for RIM is that the BlackBerry Colt is still in testing and the specifications could easily change before the device's release.
Enhanced by Zemanta

Wednesday, August 10, 2011

Facebook aims to replace texting

Image representing Facebook as depicted in Cru...

Facebook has launched an instant messaging service for mobile phones, similar to BlackBerry Messenger.
The dedicated app, for iPhones and Android devices, allows users to contact individual friends or groups of people.
Its release comes a month before Apple is due to unveil a similar product.
Attention has been focused on mobile messaging recently because some of the London rioters were known to have used it to co-ordinate their movements.
So far Facebook's mobile messenger is only available in the United States, but it is expected to eventually roll out in other countries.
The social network's 750 million users already have the ability to send messages through the website, and on Facebook's original smartphone app.
Its new application adds the option to send directly to a mobile phone via SMS, and also to include location information.
Bad timing?
Facebook's timing has raised a few eyebrows within the industry, given the debate around BlackBerry Messenger's role in the recent UK rioting.
However, it is likely that its decision to launch in the US now was influenced by the impending Arrival of Apple's iOS 5 and its integrated messenger.
Stuart Miles, the founder of Pocket-lint.com, told BBC News that Facebook might be able to make mileage out of its compatibility with more than one phone system.
"Apple will be iPhone to iPhone, like Facetime. The same as BBM which is Blackberry to Blackberry. [Facebook] will be Android to iPhone, so theoretically it can only benefit from the platform," said Mr Miles.
"The big question you have to ask is how long will it be before Google+ has a messaging service built-in."

Enhanced by Zemanta

Rare dinosaur tracks discovered in Oz

Tyrannosaurus rex, Palais de la Découverte, Paris
A group of more than 20 polar dinosaur tracks have been discovered on the coast of Victoria, Australia, offering a rare glimpse into animal behaviour during the last period of pronounced global warming, about 105 million years ago. The discovery is the largest and best collection of polar dinosaur tracks ever found in the Southern Hemisphere.
“These tracks provide us with a direct indicator of how these dinosaurs were interacting with the polar ecosystems, during an important time in geological history,” said Emory palaeontologist Anthony Martin, who led the research.
The three-toed tracks are preserved on two sandstone blocks from the Early Cretaceous Period.
They appear to belong to three different sizes of small theropods – a group of bipedal, mostly carnivorous dinosaurs whose descendants include modern birds.
Numerous borings in a Cretaceous cobble, Farin...
The tracks were found on the rocky shoreline of remote Milanesia Beach, in Otways National Park.
One sandstone block has about 15 tracks, including three consecutive footprints made by the smallest of the theropods, estimated to be the size of a chicken.
Enhanced by Zemanta