Hints of new dark force seen in galactic smash-ups

Colliding clusters of galaxies may hold clues to a mysterious dark force at work in the universe. This force would act only on invisible dark matter, the enigmatic stuff that makes up 86 per cent of the mass in the universe.

Dark matter famously refuses to interact with ordinary matter except via gravity, so theorists had assumed that its particles would be just as aloof with each other. But new observations suggest that dark matter interacts significantly with itself, while leaving regular matter out of the conversation.

"There could be a whole class of dark particles that don't interact with normal matter but do interact with themselves," says James Bullock of the University of California, Irvine. "Dark matter could be doing all sorts of interesting things, and we'd never know."

Some of the best evidence for dark matter's existence came from the Bullet cluster, a smash-up in which a small galaxy cluster plunged through a larger one about 100 million years ago. Separated by hundreds of light years, the individual galaxies sailed right past each other, and the two clusters parted ways. But intergalactic gas collided and pooled on the trailing ends of each cluster.

Mass maps of the Bullet cluster showed that dark matter stayed in line with the galaxies instead of pooling with the gas, proving that it can separate from ordinary matter. This also hinted that dark matter wasn't interacting with itself, and was affected by gravity alone.

Musket shot

Last year William Dawson of the University of California, Davis and colleagues found an older set of clusters seen about 700 million years after their collision. Nicknamed the Musket Ball cluster, this smash-up told a different tale. When Dawson's team analysed the concentration of matter in the Musket Ball, they found that galaxies are separated from dark matter by about 19,000 light years.

"The galaxies outrun the dark matter. That's what creates the offset," Dawson said. "This is fitting that picture of self-interacting dark matter." If dark matter particles do interact, perhaps via a dark force, they would slow down like the gas.

This new picture could solve some outstanding mysteries in cosmology, Dawson said this week during a meeting of the American Astronomical Society in Long Beach, California. Non-interacting dark matter should sink to the cores of star clusters and dwarf galaxies, but observations show that it is more evenly distributed. If it interacts with itself, it could puff up and spread outward like a gas.

So why doesn't the Bullet cluster show the same separation between dark matter and galaxies? Dawson thinks it's a question of age – dark matter in the younger Bullet simply hasn't had time to separate.

New window

The idea complements a previous study that saw evidence for dark forces at work in the Bullet cluster. In 2007 Glennys Farrar of New York University and colleagues said that the smaller cluster was moving too fast for gravity alone to be responsible. They suggested that some mysterious force related to dark matter might be hurrying it along.

Still, two clusters is not a lot to go on. Dawson, Bullock and colleagues are following up with about 20 more galactic collisions to see if they show any unusual behaviours. "I really think that we're almost to the point where we have enough observational data in hand," Dawson said. "We could close the book on self-interacting dark matter."

If the new force does exist, we might soon be able to see its effects on things influenced by dark matter, such as the behavior of black holes or the masses of the first stars, says Douglas Finkbeiner of Harvard University in Cambridge, Massachusetts, who was not involved in the new study.

"The simple thing isn't always the right thing, so I really appreciate that Will is trying to look into these other possibilities," he says.

Louis Strigari of Stanford University in California agrees. "Self-interacting dark matter is worth pursuing because we're still very ignorant," he said. "We're desperate to understand what dark matter is, so any new window is welcome."

If you would like to reuse any content from New Scientist, either in print or online, please contact the syndication department first for permission. New Scientist does not own rights to photos, but there are a variety of licensing options available for use of articles and graphics we own the copyright to.

All comments should respect the New Scientist House Rules. If you think a particular comment breaks these rules then please use the "Report" link in that comment to report it to us.

If you are having a technical problem posting a comment, please contact technical support.

Read More..

EU leaders want UK in union, but not treaty change

LONDON: European leaders on Wednesday stressed the importance of keeping Britain in the EU, but said they opposed treaty changes demanded by Prime Minister David Cameron.

"Britain is an essential part of the EU," Irish Prime Minister Enda Kenny said during a conference in Dublin marking the beginning of his country's six-month presidency of the bloc.

"Great Britain has great value and is a very important member of the EU," added EU President Herman Van Rompuy.

The two leaders highlighted the importance of the union for British businesses, saying that it was essential for them that Britain remained a full and active member.

A majority of Britons favour severing all ties with the union, according to polls, and Cameron is expected to deliver a speech within the next few days spelling out his views on the country's relationship with Brussels.

He insisted last year that he supported Britain's membership, but that he wanted to negotiate a "new agreement" which would allow it to opt out of certain directives.

Kenny and Van Rompuy both repeated their opposition to any treaty changes.

"I don't see a reopening of the treaties, I don't see an issue in treaty change for any individual countries," said the Irish prime minister.

Irish Deputy Prime Minister Eamon Gilmore stressed that the top concern of European citizens, "whether from Liverpool or Limerick", was unemployment.

Van Rompuy reiterated that it would be possible to change the treaties after the 2014 European elections, but added that he strongly supported deeper EU integration as opposed to an "a la carte" union.

He pointed out that there was already scope for increasing EU partnership.

"We don't need, at this stage, a treaty change," he said. "We can deliver for a deeper EU within the treaties."

- AFP/jc

Read More..

Apple updates App Store screenshot rules to shutter scam

Apple has thrown a block in the path of scamming developers looking to trick App Store users into downloading apps they might think is another popular game -- like Minecraft.

(Credit:
Screenshot by Rich Brown/CNET)

Apple announced a new App Store policy for developers today that effectively puts an end to a common bait-and-switch scam.

In a note on its Developer Portal, Apple said screenshots submitted by developers to accompany app descriptions in its App Store will be locked in place when the app wins approval.

Beginning January 9, app screenshots will be locked in iTunes Connect once your app has been approved. New screenshots may be uploaded when you submit a binary for an update to an existing app or a new app.

Before the new policy went in to place, app developers would often upload legitimate game screenshots to accompany the app description, then switch them out for screenshots that resembled more popular games once the app was approved. The switch often snagged unsuspecting victims who assumed they were downloading a different app.

The popular game Minecraft was a frequent target of clone apps, with developers lifting screenshots from the game to promote an unrelated game. One example, cited by Panic Blog, showed a game called Mooncraft with a Minecraft app image that billed itself as "a moon-themed Minecraft-type game for iOS." But as a Panic video shows (see below), the game was instead an app that featured building blocks labeled with numbers and letters.

While this presumably means that scamming developers will no longer be able to game the App Store, it also hobbles legitimate developers trying to keep their app descriptions up to date.

(Via MacRumors)

Read More..

Embryonic Sharks Freeze to Avoid Detection

Jane J. Lee

Although shark pups are born with all the equipment they'll ever need to defend themselves and hunt down food, developing embryos still stuck in their egg cases are vulnerable to predators. But a new study finds that even these baby sharks can detect a potential predator, and play possum to avoid being eaten.

Every living thing gives off a weak electrical field. Sharks can sense this with a series of pores—called the ampullae of Lorenzini—on their heads and around their eyes, and some species rely on this electrosensory ability to find food buried in the seafloor. (See pictures of electroreceptive fish.)

Two previous studies on the spotted catshark (Scyliorhinus canicula) and the clearnose skate (Raja eglanteria)—a relative of sharks—found similar freezing behavior in their young. But new research by shark biologist and doctoral student Ryan Kempster at the University of Western Australia has given scientists a more thorough understanding of this behavior.

It all started because Kempster wanted to build a better shark repellent. Since he needed to know how sharks respond to electrical fields, Kempster decided to use embryos. "It's very hard to test this in the field because you need to get repeated responses," he said. And you can't always get the same shark to cooperate multiple times. "But we could use embryos because they're contained within an egg case."

Cloaking Themselves

So Kempster got his hands on 11 brownbanded bamboo shark (Chiloscyllium punctatum) embryos and tested their reactions to the simulated weak electrical field of a predator. (Popular pictures: Bamboo shark swallowed whole—by another shark.)

In a study published today in the journal PLoS One, Kempster and his colleagues report that all of the embryonic bamboo sharks, once they reached later stages of development, reacted to the electrical field by ceasing gill movements (essentially, holding their breath), curling their tails around their bodies, and freezing.

A bamboo shark embryo normally beats its tail to move fresh seawater in and out of its egg case. But that generates odor cues and small water currents that can give away its position. The beating of its gills as it breathes also generates an electrical field that predators can use to find it.

"So it cloaks itself," said neuroecologist Joseph Sisneros, at the University of Washington in Seattle, who was not involved in the study. "[The embryo] shuts down any odor cues, water movement, and its own electrical signal."

Sisneros, who conducted the previous clearnose skate work, is delighted to see that this shark species also reacts to external electrical fields and said it would be great to see whether this is something all shark, skate, and ray embryos do.

Marine biologist Stephen Kajiura, at Florida Atlantic University, is curious to know how well the simulated electrical fields compare to the bamboo shark's natural predators—the experimental field was on the higher end of the range normally given off.

"[But] they did a good job with [the study]," Kajiura said. "They certainly did a more thorough study than anyone else has done."

Electrifying Protection?

In addition to the freezing behavior he recorded in the bamboo shark embryos, Kempster found that the shark pups remembered the electrical field signal when it was presented again within 40 minutes and that they wouldn't respond as strongly to subsequent exposures as they did initially.

This is important for developing shark repellents, he said, since some of them use electrical fields to ward off the animals. "So if you were using a shark repellent, you would need to change the current over a 20- to 30-minute period so the shark doesn't get used to that field."

Kempster envisions using electrical fields to not only keep humans safe but to protect sharks as well. Shark populations have been on the decline for decades, due partly to ending up as bycatch, or accidental catches, in the nets and on the longlines of fishers targeting other animals.

A 2006 study estimated that as much as 70 percent of landings, by weight, in the Spanish surface longline fleet were sharks, while a 2007 report found that eight million sharks are hooked each year off the coast of southern Africa. (Read about the global fisheries crisis in National Geographic magazine.)

"If we can produce something effective, it could be used in the fishing industry to reduce shark bycatch," Kempster said. "In [America] at the moment, they're doing quite a lot of work trying to produce electromagnetic fish hooks." The eventual hope is that if these hooks repel the sharks, they won't accidentally end up on longlines.

Read More..

White House Won't Rule Out $1 Trillion Coin

(United States Mint/Wikimedia Commons)

White House Press Secretary Jay Carney today flatly ruled out any negotiations with Congress over raising the debt ceiling, but there’s one odd-ball solution he would not rule out:  minting trillion dollars coins to pay off the debt.

“There is no Plan B. There is no backup plan. There is Congress’s responsibility to pay the bills of the United States,” White House Press Secretary Jay Carney told reporters at the daily White House briefing.

READ: $1-Trillion Coins: The Ultimate Debt Ceiling End-Around?

Asked if the administration would rule out minting trillion dollars coins if Congress fails to act, Carney deflected saying “you could speculate about a lot of things.”

“Nothing needs to come to these kinds of… speculative notions about how to deal with a problem that is easily resolved by Congress doing its job, very simply,” he added.

Pressed further on why they won’t offer a clear yes-or-no answer to the question, Carney referred questions to the Treasury Department.

“I answered it thoroughly,” he later joked. “And I have no coins in my pocket.”

Some have suggested the President could invoke the 14^th Amendment to the Constitution – which states, “the validity of the public debt of the United States … shall not be questioned” – and ignore the debt ceiling altogether.  On that question, Carney has offered a straight answer:  the 14 Amendment does not apply to the debt ceiling.

“We just don’t believe that it provides the authority that some believe it does,” Carney said.

The trillion-dollar-coin idea has been floated by, among others, an economist at the American Enterprise Institute.

Here’s our full Q and A:

KARL: I heard you unequivocally rule out using the 14th Amendment on the debt ceiling. I heard you unequivocally rule out negotiating with Congress. But you did not rule out this trillion-dollar coin idea. So can I ask you just a yes-or-no question? Does the White House rule out the idea of minting trillion-dollar coins as a way of dealing with the debt ceiling?

CARNEY: I would refer you to Treasury for the specifics of this question. I can tell you that the president does not believe that there is a backup plan or a plan B or an off-ramp. The only viable option here is Congress to fulfill its — that Congress fulfills its responsibility and ensures that the United States of America pays its bills, as it has always paid its bills throughout its history.

KARL: But why have we ruled out the 14th Amendment and not ruled out the trillion-dollar coin idea?

CARNEY: Again, I can tell you that there are no back-up plans. There are no plan B’s. I’d refer you to the Treasury.

–

KARL: Jay, the speaker of the House has made it perfectly clear that he is willing to increase the debt ceiling, but the principle is for every dollar the debt ceiling is increased, a dollar of spending must be cut. Given that you’re saying that the White House will not negotiate on raising the debt ceiling, are you willing to accept that principle from the speaker, a dollar in cuts for every dollar increase?

MR. CARNEY: I think the president’s been very clear that his absolute principle is that we need to reduce our deficit in a balanced way that does not shift all the burden, through cuts exclusively, on senior citizens, on families who have disabled children, on families who are trying to send their kids to school. That’s just unacceptable.

You know, one of the things we learned in the process that we just went through late in — late last year is that when it comes to specificity, we never saw any specificity from Republicans in terms of how exactly they would achieve the kind of sweeping cuts that they say they want and out of whose — you know, from whom would they demand that payment.

And what the president has been very clear about is he will not negotiate on Congress’ responsibility to pay its bills. He will negotiate and is willing to compromise, as he has demonstrated repeatedly, when it comes to moving forward in a balanced way to reduce our deficit. We have to deal with the sequester. We have to deal with a variety of budgetary and economic and fiscal challenges.

But he will not negotiate over the debt ceiling. And the threat itself is a problem, as we saw in the summer of 2011. The binary choice that Republicans seem to want to present to the American public is either we gut Medicare and Social Security or we tank the global economy. I’m not a communications director for the speaker of the House or the Senate minority leader, but I would think selling that would be very hard.

KARL: But help me understand how this works. You say you will not negotiate on this issue. They’ve put out a principle, so they produce something — and they say they will — that cuts a dollar for every dollar increase. And you’re saying you won’t negotiate on that?

MR. CARNEY: Have you seen that?

KARL: Well, this is what they say they are going to go forward.

MR. CARNEY: Well, I mean, you know –

KARL: So either –

MR. CARNEY: — words are not actions, and there has been, at — to this date, very little specificity, you know, since we — since the Ryan plan, which itself was lacking in specifics. And if their — if their position is we’re going to voucherize Medicare or tank the global economy, they should say so. That is unacceptable to the American people. It’s certainly unacceptable to the president.

Look, here’s the thing. Congress has the authority to authorize money, right, not the president. Congress racked up these bills. Congress has to pay these bills. We are very interested in a discussion and negotiation about getting our fiscal house in order. This president has already signed into law over $2 trillion in deficit reduction. He is eager to do more in a balanced way.

But it is not appropriate to — in this president’s view — to say that if I don’t get what I want, I’m not going to raise the debt limit. That is basically saying, I will abandon the history of the United States maintaining the full faith and credit of its currency and its — and its treasury by refusing to pay bills because I didn’t get what I want politically.

And that’s just not acceptable to the president.

KARL:  I’m not sure I understand how that works — you’re not going to negotiate at all? –

MR. CARNEY: We’re not going to negotiate. Congress has a — if Congress wants to give the president the responsibility to raise the debt ceiling, he would take it, as we saw when — in 2010 or — I forget, there have been so many of these confrontations — in — when — in 2011 when the so-called McConnell plan was adopted, you know. But they assigned themselves this responsibility. They need to be — the fact that they, you know, assigned it to them is something that they have to deal with. They assigned it to themselves, they need to act, and they need to, without drama or delay, raise the debt ceiling. We still have — there is plenty of opportunity outside of threatening the full faith and credit of the United States to debate fundamental differences over our economic and fiscal policy proposals, but it is not wise to do that around raising the debt ceiling, not wise to do it around the simple principle that we, the United States of America, pay our debts.

Read More..

Pruney fingers give us better grip underwater

WHY do our fingers do prune impressions when soaked? It could be an adaptation that gives us better grip underwater.

Fingers and toes wrinkle in water after about 5 minutes due to the constriction of blood vessels. This reduction in volume pulls the skin inward, but as the skin's surface area cannot change, it wrinkles. A study in 2011 showed that wrinkles form a pattern of channels that divert water away from the fingertip – akin to rain treads on tyres. The team thought that this could aid grip.

To find out, Tom Smulders and his team at Newcastle University, UK, timed people as they transferred wet or dry objects from one box to another with and without wrinkled fingers.

With wrinkles, wet objects were transferred about 12 per cent faster than with unwrinkled fingers. The time it took to transfer dry objects was the same regardless of wrinkles.

So why aren't our digits always prune-like? "With wrinkles, less of your skin surface touches the object, so there may be issues of sensitivity," Smulders suggests.

Journal reference: Royal Society Biology Letters, DOI: 10.1098/rsbl.2012.0999.

If you would like to reuse any content from New Scientist, either in print or online, please contact the syndication department first for permission. New Scientist does not own rights to photos, but there are a variety of licensing options available for use of articles and graphics we own the copyright to.

All comments should respect the New Scientist House Rules. If you think a particular comment breaks these rules then please use the "Report" link in that comment to report it to us.

If you are having a technical problem posting a comment, please contact technical support.

Read More..

Arianespace says 2012 sales leapt by 30%

PARIS: The European space launch company Arianespace said Tuesday that its 2012 sales rose 30 per cent and forecast that it would dominate Russian and US rivals this year with a market share of more than 60 per cent.

Arianespace sales soared to more than 1.3 billion euros, and the company said that it already covered 60 per cent of the global market last year, bringing its order book to 4.0 billion euros, or three years' worth of activity.

This year, the company plans 12 launches with three different vehicles, the giant Ariane 5 rocket, the smaller Vega, and the Russian rocket Soyuz, up from 10 in 2012, chief executive Jean-Yves Le Gall told a press conference.

He called 2012 a "remarkable" year, noting that the company had launched seven Ariane 5 rockets to mark its 10th consecutive year without a failure, and had put a total of 75 tonnes of satellites into orbit.

Arianespace could even surpass 12 launches this year if one of its rivals is unable to honour their contracts, Le Gall noted, joking: "When they sign contracts we are the one that launches the satellites."

Competitors include the private US firm SpaceX, which developed its own launch vehicle over a period of 10 years and successfully delivered a payload last year to the International Space Station with its reusable Dragon launch vehicle.

The Russian rocket Proton has had a spotty launch record meanwhile, but its successor Angara is set for its first launch this year.

Elsewhere, the US-Russian company Sea Launch is in financial trouble, while Chinese rockets are not yet serious rivals for Arianespace.

The European group still depends on subsidies from countries that have backed it from the beginning, but Le Gall estimated that it needed a little more than 100 million euros last year, down from 125 million a year before, and 250 million 10 years earlier.

Ariane 5 is to be replaced by an Ariane 6 rocket, pending confirmation of that project next year. Arianespace forecasts that it would then be profitable without public aid.

- AFp/jc

Read More..

How to set up an Eject All hot key in OS X

If you have a MacBook system that you regularly use at a desk such as in an office work space, then you may have a number of peripheral storage devices set up to manage backups and work-specific data, whether attached directly to the system or through a Thunderbolt, FireWire, or USB docking device. These can be convenient when you need them, but quite the opposite when you're packing up to depart.

The main reason for this is OS X's requirement that you manually unmount each drive that's attached to the system by either dragging it to the trash, clicking the eject button next to it in the Finder sidebar, or using the Eject function in the system or contextual menus. If you have multiple drives attached, you will need to systematically eject each one or chance interrupting communication with the drive, which may result in data loss.

While this isn't as much of an issue with desktop systems, with a laptop it is often easy to close the lid and pull the plugs to quickly be on your way, only to wake the system to a number of warnings about not having properly ejected your disks.

Set up this Automator work flow as a systemwide service, which can then be bound to a hot key for quick access to unmount any attached drive (click for larger view).

(Credit:
Screenshot by Topher Kessler/CNET)

Luckily, with the use of Terminal commands and Apple's Automator utility you can set up a hot key to quickly unmount all drives from your system, which should speed up your escape.

To do this, first open the Automator utility in the OS X Applications folder, and then follow this procedure:

1. Create a new Service work flow


2. Set the service to receive "No Input" but work in "All Applications"


3. Locate and drag the Run Shell Script action to the work flow window


4. Change the default "cat" command to the following two commands (the first removes all "ejectable" media like optical disks, and the second unmounts all drives except for those in use, such as the boot drive):

   diskutil eject /Volumes/*
   diskutil unmountDisk /Volumes/*



5. Save the service with an appropriate name (such as EjectAll)

At this point you can test the work flow to see if it ejects your disks for you (it should). Since the work flow is a service that is available for all applications, it should now be available in the Services submenu of the application menu (next to the Apple menu) for the foremost program. Additionally, you can set a custom hot key to invoke this service at any time. To do this, go to the Keyboard system preferences and select the Services section in the Keyboard Shortcuts tab. In here, locate the new service by the name you gave it (it should be listed under General) and click the "Add shortcut" button to assign a hot-key sequence to it.

With this done, you can now invoke the hot-key sequence or select the service from the application menu to quickly unmount and eject all attached drives and have your system ready to go.

---

Questions? Comments? Have a fix? Post them below or !
Be sure to check us out on Twitter and the CNET Mac forums.

Read More..

Pictures: Wildfires Scorch Australia Amid Record Heat

Photograph by Jo Giuliani, European Pressphoto Agency

Smoke from a wildfire mushrooms over a beach in Forcett, Tasmania, on January 4. (See more wildfire pictures.)

Wildfires have engulfed southeastern Australia, including the island state of Tasmania, in recent days, fueled by dry conditions and temperatures as high as 113ºF (45ºC), the Associated Press reported. (Read "Australia's Dry Run" inNational Geographic magazine.)

No deaths have been reported, though a hundred people are unaccounted for in the town of Dunalley, where the blazes destroyed 90 homes.

"You don't get conditions worse than this," New South Wales Rural Fire Service Commissioner Shane Fitzsimmons told the AP.

"We are at the catastrophic level, and clearly in those areas leaving early is your safest option."

Published January 8, 2013

Read More..

Menu Calorie Counts: How Accurate Are They?

They are supposed to help America's obesity problem: calorie counts boldly displayed on restaurant menus across the country and important information, considering Americans now eat one-third of their meals outside the home.

Two states and nine counties require them today, and by the middle of next year, a federal law is expected to force chain restaurants, convenience stores and vending machines nationwide to post calorie counts.

But how accurate are those numbers that so affect your waistline?

A 2011 study by Tufts University sampling food from 42 restaurants says it depends.

Fast food restaurants were the most accurate because of the uniform recipes and portions, but there were wide variations found in sit-down restaurants.

"We found that 20 percent of the foods we tested had 100 calories or more over what was stated on the menu," Lorien Urban, a postdoctoral associate in the energy metabolism lab at Tufts University and first author of the study, told ABC News. "We would consider that to be a considerable amount."

Urban explained that consuming an extra 100 calories per day can lead to an extra 10 pounds in one year.

Most concerning was that a majority of the errors Urban and her colleagues found were made on the diet side of the menu.

"These were the foods that people who are trying to manage their weight would gravitate towards and they may be getting more calories than they expect," she said.

ABC News sent producers in three cities that already require posting menu calories to major chains to do a sampling under the direction of a nationally known lab and found that more than half of the low-cal meals tested had more calories than listed on the menu.

In total 24 food samples from four sit-down restaurants and one McDonald's were collected and the results were surprising.

McDonald's did the best. Its Big Mac Meal (posted: 930) and its Premium Chicken Sandwich (posted: 400) tested 30 calories below the menu posting.

But the sit-down restaurants had results sometimes wildly different than advertised.

In all, only one calorie count was accurate -- a Skinnylicious chicken salad sandwich from the Cheesecake Factory.

Eleven meals had more calories than on the menu and 10 had fewer calories. Some were over by only 40 calories; another was over by as much as 420 calories, again at the Cheesecake Factory: This time an order of the fish and chips dinner.

Urban said that fast food restaurants tended to be more accurate than sit-down because of the formulaic preparation that fast food restaurants use.

"Things are arriving already packaged into the restaurants and it's just a matter of warming it up and serving it to the consumer," she said. "A sit-down restaurant, things are being prepared on [the] spot [and] by chance some extra butter gets into the pan."

That can change the calorie amount.

All the restaurants and their trade association say that most calorie counts are as accurate as possible and tested extensively to make sure.

They conceded that there are variations, mostly due to portion size and individual restaurant preparation, and that the menus warn actual calories may vary.

What can you do? Take control of what is put on top of the entree by asking for everything fattening -- such as cheeses, sauces or dressings -- on the side.

Read More..