Showing posts with label Science and Technology. Show all posts
Showing posts with label Science and Technology. Show all posts

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.

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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.

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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."

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Wednesday, August 10, 2011

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.
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Giant fossil shows huge birds lived among dinosaurs


An enormous jawbone found in Kazakhstan is further evidence that giant birds roamed - or flew above - the Earth at the same time as the dinosaursLower jaw of S. nessovi (Naish/Dyke/Cau/Escuillié/Godefroit).
Writing in Biology Letters, researchers say the new species, Samrukia nessovi, had a skull some 30cm long.
If flightless, the bird would have been 2-3m tall; if it flew, it may have had a wingspan of 4m.
The find is only the second bird of such a size in the Cretaceous geologic period, and the first in Asia.
The only other evidence of a bird of such a size during the period was a fossilised spinal bone found in France and reported in a 1995 paper in Nature.
Sharing space
An overwhelming majority of the birds known from the period would have been about crow-sized, but Dr Darren Naish of the University of Portsmouth said that a second find of an evidently different species suggests that large birds were common at the time.
"This fossil is only known from its lower jaw, so unfortunately we can't say anything at all with certainty about the shape and form of the whole animal.
"If it was flightless and sort of ostrich-shaped, it would have been maybe 2-3m tall and somewhere over 50kg," he explained to BBC News. "If it was a flying animal, then maybe it was shaped like a big albatross or a condor."
Dr Naish also wondered about the dinosaurs with which the enormous birds shared their space.
"I think the really interesting thing is that they're living alongside the big dinosaurs we know were around at the time: big tyrannosaurs, long-necked sauropods, duck-billed dinosaurs," he said. "That opens up loads of questions about ecological interactions that we can only speculate about.
"People have said there weren't big birds when there were big pterosaurs, but now we know there were."

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Tuesday, August 9, 2011

CHIMPANZEES NOT AS SELFISH AS WE THOUGHT

Common chimpanzee in the Leipzig Zoo.

Humans aren't the only altruistic primates. New research demonstrates chimpanzees also show unselfish concern for the welfare of others.
The study, published in the latest Proceedings of the National Academy of Sciencesnegates prior findings that concluded chimpanzees are "indifferent to the welfare" of their fellow chimps.
Insects and many other creatures help each other out, but it's believed that primate altruism is empathy-based, with this trait being widespread among mammals.
"Since empathy is an old mammalian trait, there is no reason why the sort of altruism we describe should be unique for the primates," co-author Frans de Waal, director of the Living Links Center at the Yerkes Primate Center, told Discovery News.
NEWS: Chimps Have Better Sex Than Humans
"I expect it will be found in dogs (and) rats," he added. "We, and others, found it previously in monkeys: capuchin monkeys, marmosets, tamarins."
For this latest study, de Waal and colleagues Victoria Horner, J. Devyn Carter and Malini Suchak presented 7 female chimps with a bucket containing 30 tokens. The scientists chose to look at all females to avoid potential sex-based conflicts.
For each experiment, the tokens came in two different colors. Choosing tokens of a certain color would result in a "selfish outcome," which was a food reward for just the participant. Choosing tokens of the other color resulted in food rewards for both the token selector and another nearby chimp in an adjacent compartment.
The food rewards consisted of banana slices wrapped in butcher paper that made a loud sound when unwrapped.
The chimp participants nearly always chose the tokens that would yield food rewards for both the selector and the nearby observing chimp. They would do this with or without solicitation from the chimp bystander, who could smell the bananas and hear the tantalizing paper unwrapping. At times the bystanders begged, whined and even spit water. Such behavior didn’t help their cause much, contradicting prior suggestions that chimps only share when under social pressure.
The researchers believe earlier studies confused chimp participants, since the experiments involved rather complex apparatuses. These earlier studies, according to lead author Horner and her team, also promoted competition, caused the chimps to become preoccupied with visible reward options, and permitted little communication among the chimps. In this study, “extensive communication” between the participants took place.
Christophe Boesch, director of the Department of Primatology at the Max Planck Institute for Evolutionary Anthropology, told Discovery News, "All studies with wild chimpanzees have amply documented that they share meat and other food abundantly, that they help one another in highly risky situations, like when facing predators or neighboring communities, and adopt needing orphans."
Given this information, both he and de Waal expressed frustration over the earlier research that concluded chimpanzees were essentially selfish animals.

Boesch said altruistic behavior happens in the wild in purely social situations and not through the detour of a complicated and very artificial apparatus.
"By increasing the social and ecological validity of their experiments, (Horner and her colleagues) have been able for the first time to duplicate what field researchers already knew was a natural ability of chimpanzees," Boesch said.
He concluded, "Such a confirmation is very timely and welcome, but the real question is why could previous experiments with so little ecological validity be published with such sweeping general claims?"
 
Scientists are also interested in identifying what makes humans unique from other primates and animals. Now altruism can be taken off the list, since it’s likely that all mammals, at least to some extent, can show empathy-based concern for others. Associated traits must have therefore emerged very early in mammalian evolution.

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Monday, August 8, 2011


State run Telco Mahanagar Telephone Nigam Ltd (MTNL) has finalised 3G roaming agreements with two private telecom firms Aircel and Tata Tele in the Delhi and Mumbai circles.
The agreement could generate around Rs.250 to Rs.300 crore in additional annual revenues for MTNL, which will prove helpful since it has been bleeding financially. In 2010-11 itself, the net loss was Rs.2,827 crore.

Airtel, Vodafone and Reliance were the only ones who got licenses for 3G in both the metro cities, since these two were the costliest circles for 3G; Delhi’s bid was Rs.3,317 crore while Mumbai’s was Rs.3,247 crore. The new agreement between MTNL and the two Telco will allow them to provide their subscribers in the two cities with 3G services even though they don’t have licenses for them.

Recently, the company had a meeting with the department of telecommunications to discuss the subject of 3G roaming agreements and it is in this meeting that the green signal was given.

“We are in discussions with both of them (Tata Teleservices and Aircel). We will shortly announce the final deal,” said Kuldeep Singh, MTNL chairman and managing director, according to afaqs.

Aircel already has 3G spectrum licenses in 13 circles and had added 0.91 million customers in June taking its subscriber base to 57.98 million. Tata Teleservices on the other hand has 3G license for 9 circles.

Just last month, rivals Bharti Airtel, Vodafone and Idea got into inter and intra-circle roaming agreements to provide 3G services to their respective customers across India. The agreement between the three Telco’s allowed each of them to have a pan India presence and that too at reduced costs. Although the financial details of the revenue share agreement were not disclosed.

With the growing popularity of 3G in India and the storm of 3G enabled smartphones in the country, the Telco’s had to get into some kind of an agreement eventually, since Delhi and Mumbai are two very important circles.

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ET Review: HTC Flyer, a pen to rule them all

Image representing Android as depicted in Crun...
HTC has a solid reputation with smartphones. That's why it's no surprise that their first tablet, the Flyer, sticks to the tried-and-tested smartphone plan. The family resemblance - especially to other metal-bodied HTC phones is evident. 

The Flyer has the sort of aluminium unibody design first made popular by Android phones like the Legend. It's reassuringly solid to hold with no flexing - however, the two white plastic inserts on the back are a different story. The top plastic cover slides off (with some difficulty) to reveal the micro SD and SIM card slot. 
Wordmark of HTC. Trademarked by HTC.
The lower plastic cover serves no purpose and oddly, sticks out a fair bit, making this portion the thickest part of the tablet. Presumably, it hides the GSM/Wi-Fi/Bluetooth antenna, which would not work very well behind thick metal. 

Overall size is similar to other 7-inch tablets like the BlackBerry Playbook and Samsung Galaxy Tab, although thanks to the extensive use of metal, it tips the scales at 420 grams (the BlackBerry Playbook is 425 grams while the Samsung Galaxy Tab P1000 is 380 grams). 





Unlike other new Android tablets which are flocking to the tablet-specific Android 3.0, the Flyer sticks with Android 2.3 with HTC Sense - HTC has customized their Sense user interface for tablets instead. The advantage of course, is that the full suite of 3,00,000 Android apps is available. The disadvantage is that many of these apps have been designed for smaller phone screens in the first place, so they may not display 'ideally' on a 7-inch screen. 

A nice touch are the two sets of capacitive buttons - depending on whether you're holding the Flyer in portrait or landscape, the appropriate set of buttons will light up. 

Aerial picture of the HTC Espresso
The party trick of the Flyer is the pen input, called HTC Scribe. A battery-powered pen supplied with the unit can be used to write and draw on the screen with more precision than a capacitive stylus will permit. The pen also registers pressure - so drawing lightly will create a thin line but press a little harder and you'll get a thicker line. You can always change pen styles (pen, pencil, brushes), colours and line thickness too. To activate Scribe, you have to use the pen to tap on the pen icon near the capacitive buttons. You can have endless fun taking photographs and drawing on them, taking a screenshot of anything on the screen and drawing on it or just using a blank notepad. 
Two problems here: the pen is not really a capacitive stylus, so it only works in pen mode. When using the pen, there will be occasions when you have to tap a button using your finger - constantly alternating between pen and finger is sometimes confusing. Second: the pen uses a AAAA battery - not AAA, but AAAA. These are hard to find. At best, we could find them online, listed for `1,200 for six (including shipping to India) 





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US swimmer braves sharks on Cuba crossing


A 61-year-old US swimmer paddled through shark-invested waters off Cuba on Monday on a three-day journey to the United States aimed at promoting closer ties between the Cold War foes.
"We want these three days to help the two countries get closer," Diana Nyad told a press conference in Havana before embarking on her marathon swim, adding she also hoped to show that people can lead active lives after 60.
"I am a better athlete today than I was at 29," she told CNN.
A CNN reporter following the journey by boat said Nyad was almost 20 miles (32 kilometers) off the coast of Cuba by 1300 GMT.
She will have to contend with strong currents and the risk of sharks on the 166-kilometer (100-mile) crossing from Havana to the Florida Keys.
Nyad tried to cross the Florida Straits in 1978 but was forced to abandon the bid after 42 hours due to poor weather.
The following year she set an open sea record by swimming from the Bahamas to the Florida Keys (165 kilometers, 100 miles), the same distance as her current swim, but a feat she described as much less dangerous.
She will be accompanied by five yachts and four kayaks, and will be backed by a 45-person support team, including trained shark divers and electronic devices designed to repel the predators.
Australian swimmer Susie Maroney, at 22, became the first person to swim from Cuba to the United States in 1997, though she used a shark cage.
Nyad told NBC's "Today" show that she declined to use a cage, adding: "I don't want to have that asterisk next to my name."
Nyad will stop and tread water every 45 minutes to rehydrate and every 90 minutes to eat, organizers said.
The distance swimmer, who turns 62 later this month, set a record for circling the island of Manhattan at the age of 50, clocking in at seven hours and 57 minutes.
"It doesn't have to be a big moment," she told NBC about her latest feat. "It just means be engaged in your life. Don't let it go by. We all have one life and it's a one-way street."
The United States has not had diplomatic relations with Cuba since 1961 when it slapped a trade embargo on the communist-ruled island.

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