Starvation didn't wipe out saber-toothed cats

Saber-toothed cats apparently did not go extinct for lack of prey, contradicting a popular explanation for why they died off, fossil evidence now suggests.

Even near their extinction, saber-toothed cats likely had enough to eat, researchers noted.

Saber-toothed cats, American lions, woolly mammoths and other giant creatures once roamed across the American landscape. However, at the end of the late Pleistocene about 12,000 years ago, these "megafauna" went extinct, a die-off called the Quaternary extinction.

"The popular theory for the megafaunal extinction is that either the changing climate at the end of the last ice age or human activity, or some combination of the two, killed off most of the large mammals," said researcher Larisa DeSantis, a vertebrate paleontologist at Vanderbilt University in Nashville.

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"In the case of the great cats, we expect that it would have been increasingly difficult for them to find prey, especially if had to compete with humans. We know that when food becomes scarce, carnivores like the great cats tend to consume more of the carcasses they kill. If they spent more time chomping on bones, it should cause detectable changes in the wear patterns on their teeth."

Tale of the teeth
To learn more about saber-toothed diets, the researchers analyzed the fossil teeth of 15 saber-toothed cats (Smilodon fatalis) and 15 American lions (Panthera atrox) recovered from the La Brea tar pits in Los Angeles. These specimens ranged from about 11,500 to 35,000 years in age.

To study the fossils, the scientists used dental microwear texture analysis, developed by anthropologist Peter Ungar at the University of Arkansas. This involves using generating three-dimensional images of a tooth's surface. The image is then analyzed for microscopic grooves ? devouring red meat produces small parallel scratches, while biting on bones lead to larger, deeper pits.

The investigation found the pattern of wear on the teeth of the saber-toothed cat most closely resembled those of present-day African lions, which sometimes crush bone when they eat. The wear pattern on American lion teeth, on the other hand, echoed that of the present-day cheetah, which deliberately avoids bones when it feeds. [ Photos: A Lion's Life ]

Analysis of both older fossils and more recent ones did not reveal any evidence that patterns of wear changed over time, and none had extreme microwear like living hyenas, which consume entire carcasses, bones included. This suggests that prey for these carnivores was not scarce ? the animals were not gnawing their victims to the bone.

"Tooth wear patterns suggest that these cats were not desperately consuming entire carcasses, as was expected, and instead seemed to be living the 'good life' during the late Pleistocene, at least up until the very end," DeSantis said.

Big predator extinction
Past research of teeth from American lions, saber-tooth cats, dire wolves and coyotes from La Brea revealed they experienced three times the number of broken teeth of contemporary predators, hinting that these species were having trouble finding prey and were thus urgently devouring or "processing" whole carcasses. This led scientists to suspect that climate change and human competition were making life tough for the big predators.

Instead, DeSantis and her colleagues argue this high rate of damage seen in teeth more likely resulted during capture of prey instead of feeding on carcasses.

"We expected extinct carnivores to show evidence for extreme bone processing, based on the high number of broken teeth determined from prior research. Finding the complete opposite pattern was shocking!" DeSantis said.

The researchers noted that saber-toothed cats were about the size of today's African lion, while the American lion was about 25 percent larger. They fed on giants such as mammoths and four-ton giant ground sloths. The fact these ancient carnivores and their prey were bigger than contemporary predators and their victims could help explain why the extinct cats had more broken teeth than their living brethren, the investigators said. . [ Gallery: Today's Threatened Mammals ]

Specifically, larger teeth break more easily than smaller teeth, so larger carnivores may be likely to break more teeth when attempting to take down larger prey. The researchers noted past studies that found the canines of a predator the size of fox can support more than seven times the fox's weight before breaking, while a carnivore the size of lion can only support about four times its weight and the curved teeth of saber-toothed cats could only support about twice the animal's weight.

"The net result of our study is to raise questions about the reigning hypothesis that 'tough times' during the late Pleistocene contributed to the gradual extinction of large carnivores," DeSantis said. "While we can not determine the exact cause of their demise, it is unlikely that the extinction of these cats was a result of gradually declining prey."

Currently, the scientists are examining other carnivores at the La Brea tar pits, "including the extinct giant short-faced bear and the extant mountain lion that is found both during the Pleistocene at La Brea and in southern California and elsewhere today," DeSantis told LiveScience.

"Essentially, we are trying to clarify the biology and diets of these carnivores during the past to further evaluate why the short-faced bear went extinct and, potentially, why the mountain lion did not."

DeSantis and Ungar, with their colleagues Blaine Schubert and Jessica Scott, detailed their findings online Dec. 26 in the journal PLOS ONE.

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Source: http://www.msnbc.msn.com/id/50313487/ns/technology_and_science-science/

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Arab officials visit cash-strapped Palestinian territory

RAMALLAH, West Bank (Reuters) - Top Arab officials paid a rare visit to the Israeli-occupied West Bank on Saturday to discuss a Palestinian financial crisis that President Mahmoud Abbas hopes will be eased by Arab donations.

Arab League Chief Nabil Elaraby and Egyptian Foreign Minister Mohamed Kamel Amr congratulated the Palestinians on a successful United Nations status upgrade last month, but stopped short of promising the badly-needed funds.

"Palestine is in need of material and political support," Elaraby told a news conference in the Palestinians' de facto capital of Ramallah.

"Arab countries agreed at their Baghdad summit (in March) for an Arab safety net of $100 million dollars each month, but unfortunately none of this has been achieved yet," he said.

Palestinian were cheered by a strong majority in the United Nations recognizing them as an "observer state" on November 29 but have struggled to get Arab support to make up $100 million in shortfalls left by Israeli sanctions following the U.N. move.

Elaraby is the first Arab League Chief to visit Ramallah, but he and other prominent Arab and Islamic leaders, including the Egyptian prime minister, met Abbas's Palestinian Hamas rivals in Gaza during their brief war with Israel last month.

QATARI LEADER

Hamas, which split from the West Bank after it seized control of the Gaza Strip in 2007, also won a diplomatic coup by receiving Emir Hamad bin Khalifa al-Thani, ruler of the oil-rich Gulf state of Qatar, who pledged $400 million in aid for the impoverished territory in October.

The emir postponed a visit to Ramallah he had announced this month, disappointing West Bank officials who had hoped he would arrive bearing gifts of cash.

The Gaza visits broke years of diplomatic quarantine for the Islamist Hamas group, which refuses to recognize Israel or relinquish its arms, and increased the isolation of the dovish, Western-backed Ramallah government.

West Bank officials have watched with worry as uprisings in the Arab world divert attention from their diplomatic strategy, which has failed to achieve an independent Palestinian state.

Hamas militants, by contrast, have been heartened as fellow-Islamists rise to power in Egypt and elsewhere.

Abbas has accused Israel of "piracy" after it withheld customs revenues it collects on the Palestinians' behalf, citing months of utilities bills Ramallah owes Israeli companies.

The financial crisis has forced the Palestinian Authority to delay salary payments to West Bank employees, who have gone on strike in protest. Abbas has responded by saying he might give up power and compel Israel to take on the Palestinians' affairs.

"Sit in the chair here instead of me, take the keys, and you will be responsible for the Palestinian Authority," Abbas warned Israeli Prime Minister Benjamin Netanyahu, in an interview with the Israeli Haaretz newspaper this week.

"I won't do anything as long as there are diplomatic negotiations," he said. "But if the stalemate continues...what's left for us to do?"

(Reporting By Noah Browning and Ali Sawafta; Editing by Alistair Lyon)

Source: http://news.yahoo.com/arab-officials-visit-cash-strapped-palestinian-territory-140819787.html

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An Evolutionary Whodunit: How Did Humans Develop Lactose Tolerance?

Thousands of years ago, a mutation in the human genome allowed many adults to digest lactose and drink milk.

iStockphoto.com

Thousands of years ago, a mutation in the human genome allowed many adults to digest lactose and drink milk.

iStockphoto.com

Got milk? Ancient European farmers who made cheese thousands of years ago certainly had it. But at that time, they lacked a genetic mutation that would have allowed them to digest raw milk's dominant sugar, lactose, after childhood.

Today, however, 35 percent of the global population ? mostly people with European ancestry ? can digest lactose in adulthood without a hitch.

So, how we did we transition from milk-a-phobics to milk-a-holics? "The first and most correct answer is, we don't know," says Mark Thomas, an evolutionary geneticist at University College London in the UK.

Most babies can digest milk without getting an upset stomach thanks to an enzyme called lactase. Up until several thousand years ago, that enzyme turned off once a person grew into adulthood ? meaning most adults were lactose intolerant (or "lactase non-persistent" as scientists call it).

But now that doesn't happen for most people of Northern and Central European descent and in certain African and Middle Eastern populations. This development of lactose tolerance took only about 20,000 years ? the evolutionary equivalent of a hot minute ? but it would have required extremely strong selective pressure.

"Something happened when we started drinking milk that reduced mortality," says Loren Cordain, an exercise physiologist at Colorado State University and an expert on Paleolithic nutrition. That something, though, is a bit of a mystery.

The Clues

Milk, no surprise, is pretty nutritious. It's got protein, a bunch of micronutrients, lots of calcium, and plenty of carbohydrates. For the ancient Neolithic farmer, it was like a superfood, says Thomas.

Even lactose-intolerant adults could have benefited from milk. Chemical evidence from ancient pots shows that these long-ago farmers learned to process the milk into cheese or yogurt, which removes some of the lactose.

But around 8,000 years ago in what's now Turkey ? just when humans were starting to milk newly domesticated cows, goats, and sheep ? mutations near the gene that produces the lactase enzyme started becoming more frequent. And around the same time, adult lactose tolerance developed. The mutation responsible for that may be between 2,000 and 20,000 years old; estimates vary.

But in order for that new trait to have persisted over many generations, something unique must have given milk drinkers an evolutionary edge.

A Tale of Famine and Deadly Diarrhea

Thomas thinks a combination of two reasons may explain the persistence of the lactase mutation in Northern Europe.

First, the farmers that settled there came from the Fertile Crescent, and they brought crops native to that region ? like wheat and barley. But with Northern Europe's shorter growing season, these crops were more likely to fail, causing famine.

Additionally, the colder Northern European climate lent itself to natural refrigeration. "If you're a farmer in Southern Europe, and you milk a cow in the morning and you leave the milk out, it will be yogurt by noon. But if you do the same thing in Germany, it'll still be milk," says Thomas. A healthy lactose-intolerant person who drank that still-fresh milk would get a bad case of diarrhea. "But if you're malnourished, then you'll die," Thomas says.

In times of famine, milk drinking probably increased. And the very people who shouldn't have been consuming high-lactose dairy products ? the hungry and malnourished ? would be the ones more likely to drink fresh milk. So, with milk's deadly effects for the lactose intolerant, individuals with the lactase mutation would have been more likely to survive and pass on that gene.

The combination of famine and longer processing time for milk is "kind of like a double whammy," says Thomas, who has yet to publish his theory. Under his scenario, the lactose tolerant wouldn't always have had an evolutionary advantage, but for short periods of time, having that genetic mutation would have helped. "Over a long run it's modest, but over short periods of time, it's extremely high selection" for the lactose tolerant, says Thomas.

Scientists may never discover the reason why adult lactose tolerance evolved so quickly. Other researchers have suggested that fresh milk provided a more pure fluid alternative to contaminated water sources in arid environments, that milk fat gave people a fertility advantage, or that milk drinking might have been associated with social prestige. Cordain argues that milk gave humans an advantage against malaria in Africa and Southern Europe, and rickets in Northern Europe.

"Whatever constellation of factors was involved, they're going to be different in different regions," says Thomas. "But, the selection pressure might have been equally strong in East Africa and Northern Europe, for example."

It's hard to tell how prevalent lactose tolerance has been over time. But so far scientists have found evidence of adult lactase persistence in ancient skeletons in Northern Europe, Scandinavia, southern France, and elsewhere. Thomas and his colleague Oddn? Sverrisd?ttir of Uppsala University in Sweden recently discovered lactase persistence in Spanish remains from about 5,000 years ago and hope to publish their research next year.

Thomas thinks that as genetic and archaeological technology continues to develop, modern science may someday reveal the culprit. But, it might take a while because the research ? like our genes ? is still evolving.

Source: http://www.npr.org/blogs/thesalt/2012/12/28/168144785/an-evolutionary-whodunit-how-did-humans-develop-lactose-tolerance?ft=1&f=1007

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Thatcher papers show fascination with Reagan visit

LONDON (AP) ? It is not often that the president of the United States needs to seek fashion advice.

But when Ronald Reagan was getting ready for a visit to England as a guest of Queen Elizabeth II in June 1982, his people had an important question for the Brits: Just what does one wear to go riding with the queen in the magnificent horse country surrounding Windsor Castle?

The answer: Something smart, but casual, of course. Riding boots, breeches and a turtleneck sweater would do fine ? no need for formal riding attire.

The fashion inquiry is but one tidbit contained in nearly 500 pages of formerly Confidential documents relating to the Reagan visit being made public Friday by Britain's National Archives. The dossier shows the British government ? led by Prime Minister Margaret Thatcher ? to be extraordinarily interested in pleasing the relatively new president on his two-day visit. British leaders also fretted that perennial cross-Channel rivals might triumph in the tug-of-war for presidential face time in a visit that had to be sandwiched between two summits on the European mainland.

The papers show that top Reagan adviser Michael Deaver had a way of annoying his British counterparts with last-minute changes and requests, and also surprised them with some of his objectives. Deaver, remembered as a shrewd image-builder, said he wanted Reagan to be photographed outside of formal venues, so he wouldn't be seen "exclusively in white tie" at palace functions, even suggesting that Reagan go to a village pub to soak up the atmosphere

There were raised eyebrows, and bruised feelings, when the White House failed to formally reply in a timely fashion to an official invitation from the queen ? the sort of invite that usually commands respect and a prompt reply the world over. The queen's invite was left to languish for weeks and weeks, something that the British believe is simply Not Done.

"It is really for the president to respond to her invitation, which he has not done personally, something that I have pointed out several times here," writes Nicholas Henderson, Britain's ambassador to Washington, in a memo to the British Foreign Office. "As you know those surrounding the president are not deliberately rude: It is simply that they are not well-organized and do not have experience of this sort of thing."

William F. Sittman, a special assistant to Reagan who was involved in planning the trip, told The Associated Press that it is possible the delay in responding to the queen was caused by first lady Nancy Reagan's insistence on consulting her astrologer before travel plans were finalized.

"You have to remember that Mrs. Reagan was very strict about his schedule, and she would consult her astrologer to see if this was the right time to travel," he said. "Sometimes she would back up departures."

The documents make clear that Europe's leaders were desperate for Reagan's attention at a time of high Cold War tensions. A memo from U.K. Cabinet Secretary Robert Armstrong on Feb. 5 expresses concern that a gala, summit-closing dinner at the palace of Versailles outside Paris could delay Reagan's arrival in London. But he warns against pressuring the Reagan entourage to skip the meal at Versailles' Hall of Mirrors because "that would not please the President of the French Republic."

Reagan's aides also worried the British by suggesting the president might have to skip the stop in London because accepting it might anger the Germans, who had offered a similar invitation. But feelings are smoothed over a bit when the Americans assure the British contingent that the Germans are not America's top priority.

"Eagleburger emphasized how much the president himself wanted to go to London," stresses one confidential memo from the British ambassador, referring to senior U.S. diplomat Lawrence Eagleburger. "There should be no doubt about that. Eagleburger also said that at the moment the Germans were not America's favorite allies."

The prospect of a chance to relax from international summitry with a bit of horseback riding with the queen seems to have helped carry the day for the Brits. Asked for the president's favorite type of horse, British planners are told simply that he wants a thoroughbred. He ended up riding Centennial, one of the queen's favorites, and wearing a perfectly fitted sports jacket above his sweater, going for an old-time Hollywood look he carried off with ease.

Much of the actual visit was devoted to pomp and pageantry, or to relaxation, but Reagan did make one speech of consequence. He became the first American president to address a meeting of both houses of Parliament and used the occasion to trumpet his distaste for the Soviet Union, calling it an economic catastrophe.

He said Marxism-Leninism would be left on the ash heap of history ? a prediction that would come to pass in the following decade.

Associated Press

Source: http://hosted2.ap.org/APDEFAULT/cae69a7523db45408eeb2b3a98c0c9c5/Article_2012-12-28-Britain-Thatcher-Reagan/id-eeb32e39a28d4863a67f263ca633bbf4

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Worms turn metal into semiconductors

1 day

Jesse Emspak, LiveScience Contributor

Worms are useful in the garden and great for fish bait, but one of their talents has remained hidden ? until now. Scientists have discovered that worms can manufacture tiny semiconductors. ?

At King's College in London, researchers fed an ordinary red worm, Lumbricus rubellus, soil laced with metals. The worm produced quantum dots, nano-sized semiconductors that are used in imaging, LED technologies and solar cells. The experiment was published in the Dec. 23 issue of the journal Nature Nanotechnology.

The worms created these electronic components because of their ability to detoxify their body tissue. When worms ingest the metals, proteins in their body shuttle these "toxins" to tissues called chloragogen cells that are similar to a liver in mammals. In the case of?cadmium, a molecule called?metallothionein attaches to it to take it away.?Through several chemical steps the worm separates the metals from the organic molecules they are attached to and stores them in tiny cavities its body, but not forever: eventually whatever toxic metals the worm eats are excreted.?

Squirmy semiconductor factories
In the experiment the scientists spiked soil with cadmium chloride and sodium tellurite (sodium, telluride and oxygen). The ability of worms to process cadmium is well known, but it wasn't clear what they would do with the tellurium in the sodium tellurite.

The worms ended up making tiny particles of cadmium telluride, a crystalline compound that is also a semiconductor. Those tiny particles ? called quantum dots ? were then taken out of the worms' tissue. The dots themselves are only nanometers across. [Twisted Physics: 7 Mind-Bending Findings]

In biological imaging, quantum dots are used in place of dyes because they can be "tuned" to glow at specific wavelengths. Cadmium telluride dots, for example, glow green when hit with blue light. The researchers tested the dots on animal cells and found they worked as well as the ones created in laboratories.

The success doesn't mean that thousands of worms are to be sacrificed for dot-making, said co-author Mark Green, a reader in nanotechnology at King's College.

"The interesting bit is that semiconductor quantum dots, which emit light, were made in a living animal," he told Livescience via email. "The aim of the work wasn?t to come up with a new synthetic process of making dots that are better than bench-synthesized materials, it was just to see if we could do solid-state chemistry in a living animal ? and it appears we can!"

A dotty idea
Green said the idea occurred to him several years back when he was an Oxford University post-doctoral researcher. He heard a lecturer note that animals use certain proteins to get rid of toxic metals such as cadmium. Green realized he was doing something similar to make cadmium telluride quantum dots in the lab, sans worms.

He wondered if some extra chemical might spur worms to make their own cadmium telluride quantum dots.

"The big problem," he said, "was that I didn't know enough biology, and I could see immediately that trying to get the dots out of an animal would be a problem."

So Green shelved the idea for a few years, until he met Stephen St?rzenbaum, the lead author of the paper. St?rzenbaum told Green that he knew exactly where cadmium given to worms went: to the detoxifying chloragogen cells. Since the cadmium ? and thus the nanoscale dots ? would end up there, it would be relatively easy to get them out of the worm.

So they tried it. It worked.

"We were very surprised, didn't really expect it to work that easily," Green said.

The quantum dots Green and his team made aren't quite the quality of the lab-bench versions. That may change, though. "We'd like to think we can play around with some of the chemistry and make them better," Green said.

Follow LiveScience on Twitter @livescience. We're also on Facebook?& Google+.?

Copyright 2012 LiveScience, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

Source: http://www.nbcnews.com/technology/futureoftech/worms-turn-metal-semiconductors-1C7753891

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