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Home country: USA
Current location: Georgia
Member since: Tue Feb 10, 2004, 12:08 PM
Number of posts: 35,771
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An ancient skull discovered in Israel could shed light on the migration of modern humans out of Africa some 60,000 years ago.
This migration led to the colonisation of the entire planet by our species, as well as the extinction of other human groups such as the Neanderthals.
The skull from Manot Cave dates to 55,000 years ago and may be the closest we've got to finding one of the earliest migrants from Africa.
Details appear in Nature journal.
"The skull is very gracile - there is nothing that makes it any different from a modern skull," Prof Israel Hershkovitz, from Tel Aviv University, told the Nature podcast.
"But it also has traits that are found in older specimens."
He added: "This is the first evidence that shows indeed there was a large wave of migrants out of East Africa, crossing the Sahara and the Nubian desert and inhabiting the eastern Mediterranean region 55,000 years ago. So it is really a key skull in understanding modern human evolution."
Posted by n2doc | Wed Jan 28, 2015, 09:35 PM (0 replies)
The first known prehistoric human from Taiwan has been identified and may represent an entirely new species that lived as recently as 10,000 years ago, according to a new study.
The newly discovered big-toothed human, 'Penghu 1', strengthens the growing body of evidence that Homo sapiens was not the only species from our genus living in Europe and Asia between 200,000 and 10,000 years ago.
Anthropologists have learned that Neanderthals, Denisovans and Homo floresiensis (aka. the 'Hobbit') lived in Europe and Asia within that time frame.
Penghu 1, which is described in the latest issue of Nature Communications , adds to that already impressive list and might have co-existed -- and even interbred -- with our species.
Posted by n2doc | Wed Jan 28, 2015, 09:32 PM (0 replies)
Chemistry has many laws, one of which is that the rate of a reaction speeds up as temperature rises. So, in 1989, when chemists experimenting at a nuclear accelerator in Vancouver observed that a reaction between bromine and muonium—a hydrogen isotope—slowed down when they increased the temperature, they were flummoxed.
Donald Fleming, a University of British Columbia chemist involved with the experiment, thought that perhaps as bromine and muonium co-mingled, they formed an intermediate structure held together by a “vibrational” bond—a bond that other chemists had posed as a theoretical possibility earlier that decade. In this scenario, the lightweight muonium atom would move rapidly between two heavy bromine atoms, “like a Ping Pong ball bouncing between two bowling balls,” Fleming says. The oscillating atom would briefly hold the two bromine atoms together and reduce the overall energy, and therefore speed, of the reaction. (With a Fleming working on a bond, you could say the atomic interaction is shaken, not stirred.)
At the time of the experiment, the necessary equipment was not available to examine the milliseconds-long reaction closely enough to determine whether such vibrational bonding existed. Over the past 25 years, however, chemists' ability to track subtle changes in energy levels within reactions has greatly improved, so Fleming and his colleagues ran their reaction again three years ago in the nuclear accelerator at Rutherford Appleton Laboratory in England. Based on calculations from both experiments and the work of collaborating theoretical chemists at Free University of Berlin and Saitama University in Japan, they concluded that muonium and bromine were indeed forming a new type of temporary bond. Its vibrational nature lowered the total energy of the intermediate bromine-muonium structure—thereby explaining why the reaction slowed even though the temperature was rising.
The team reported its results last December in Angewandte Chemie International Edition, a publication of the German Chemical Society. The work confirms that vibrational bonds—fleeting though they may be—should be added to the list of known chemical bonds. And although the bromine-muonium reaction was an “ideal” system to verify vibrational bonding, Fleming predicts the phenomenon also occurs in other reactions between heavy and light atoms.
Posted by n2doc | Wed Jan 28, 2015, 09:29 PM (7 replies)
BY AMY DAVIDSON
Michelle Obama went to the funeral of King Abdullah—it involved, as funerals often do, an unplanned trip, with a detour from India, but the First Lady came up with an appropriate outfit. She wore loose black pants, a loose, high-cut blue shirt, and a loose printed manteau. Below her neck, only her hands were uncovered, and she was game about not offering them when the Saudi men on the reception line ignored her, or nodded vaguely. She didn’t wear a head scarf; she probably could have picked one up in India, but, really, why should she have? Saudi women must cover their heads, and often cover their faces, too; foreign women in Saudi Arabia, though, aren’t required to do so, and when Laura Bush and Hillary Clinton visited their heads were bare. In 2010, Michelle was photographed wearing a head scarf in Indonesia—those pictures were widely recirculated after King Abdullah’s funeral—but that was for a visit to a mosque. At other events in Indonesia, she didn’t bother.
Michelle Obama is an American woman, and can choose to forgo a head scarf (or to wear one). The Saudis know that; the First Lady was not a member of a landing party greeting an uncontacted culture. King Abdullah’s family includes polygamists and partiers who travel extensively, and are unlikely to have been abashed even if Michelle Obama wore a knee-length dress. One almost wishes that the First Lady’s clothing was quite the groundbreaking, grand gesture that some commentaries portrayed it as being—an “uproar,” causing “outrage,” or a “bold political statement”—but, the BBC noted, it does not seem to have made much of a stir in the kingdom, after all. (Some people tweeted about immodesty; some people always do.) Instead, the “offense” they generally seem to worry about is women in their country claiming their rights, or even insisting on power. Women in Saudi Arabia likely know too well that their rulers’ interests lie not in controlling Michelle Obama’s hair but in controlling them. This includes their assets, under the kingdom’s “guardianship” system, and their ability to make medical and educational choices, or even to drive a car. Many of them have campaigned openly for those rights, at risk to themselves, and one benefit of what is otherwise a silly controversy might be to remind Saudi women of the structure of their lives. (The videos women have made of themselves driving through Riyadh reveal more than any funeral pictures.) Neither the injustice nor what American women are wearing in Washington will be news to them. The princes, to avoid accountability for their own corruption, have accommodated Wahhabi extremists who might indeed be bothered by the idea of any woman, anywhere, appearing with her head uncovered. That is really not Michelle Obama’s problem. She doesn’t have to dress to please Al Qaeda. If she had worn a head scarf, her American critics would undoubtedly have attacked her for doing just that.
But it’s worth imagining another scenario: suppose, for reasons independent of politics, that Michelle Obama liked the way a head scarf looked. Why shouldn’t she put one on? There are, naturally, some constraints on what any First Lady wears on public occasions; jeans and sneakers at the Inauguration would be strange. But if we, at some point in this century, have a First Lady, or President, who wears any sort of headgear, for reasons related to any number of faiths (theology and millinery have historically enjoyed close alliances), what, exactly, would be the problem with that? It is right to be outraged at religious police chasing Saudi women and arresting them for supposedly immodest dress. It is also right to ask why French laws should prevent a woman in Paris from covering her face or a schoolgirl from wearing a head scarf.
Posted by n2doc | Wed Jan 28, 2015, 07:54 PM (4 replies)
BY ALEC WILKINSON
I don’t see what difference it can make now to reveal that I passed high-school math only because I cheated. I could add and subtract and multiply and divide, but I entered the wilderness when words became equations and x’s and y’s. On test days, I sat next to Bob Isner or Bruce Gelfand or Ted Chapman or Donny Chamberlain—smart boys whose handwriting I could read—and divided my attention between his desk and the teacher’s eyes. Having skipped me, the talent for math concentrated extravagantly in one of my nieces, Amie Wilkinson, a professor at the University of Chicago. From Amie I first heard about Yitang Zhang, a solitary, part-time calculus teacher at the University of New Hampshire who received several prizes, including a MacArthur award in September, for solving a problem that had been open for more than a hundred and fifty years.
The problem that Zhang chose, in 2010, is from number theory, a branch of pure mathematics. Pure mathematics, as opposed to applied mathematics, is done with no practical purposes in mind. It is as close to art and philosophy as it is to engineering. “My result is useless for industry,” Zhang said. The British mathematician G. H. Hardy wrote in 1940 that mathematics is, of “all the arts and sciences, the most austere and the most remote.” Bertrand Russell called it a refuge from “the dreary exile of the actual world.” Hardy believed emphatically in the precise aesthetics of math. A mathematical proof, such as Zhang produced, “should resemble a simple and clear-cut constellation,” he wrote, “not a scattered cluster in the Milky Way.” Edward Frenkel, a math professor at the University of California, Berkeley, says Zhang’s proof has “a renaissance beauty,” meaning that though it is deeply complex, its outlines are easily apprehended. The pursuit of beauty in pure mathematics is a tenet. Last year, neuroscientists in Great Britain discovered that the same part of the brain that is activated by art and music was activated in the brains of mathematicians when they looked at math they regarded as beautiful.
Zhang’s problem is often called “bound gaps.” It concerns prime numbers—those which can be divided cleanly only by one and by themselves: two, three, five, seven, and so on—and the question of whether there is a boundary within which, on an infinite number of occasions, two consecutive prime numbers can be found, especially out in the region where the numbers are so large that it would take a book to print a single one of them. Daniel Goldston, a professor at San Jose State University; János Pintz, a fellow at the Alfréd Rényi Institute of Mathematics, in Budapest; and Cem Yıldırım, of Boğaziçi University, in Istanbul, working together in 2005, had come closer than anyone else to establishing whether there might be a boundary, and what it might be. Goldston didn’t think he’d see the answer in his lifetime. “I thought it was impossible,” he told me.
Zhang, who also calls himself Tom, had published only one paper, to quiet acclaim, in 2001. In 2010, he was fifty-five. “No mathematician should ever allow himself to forget that mathematics, more than any other art or science, is a young man’s game,” Hardy wrote. He also wrote, “I do not know of an instance of a major mathematical advance initiated by a man past fifty.” Zhang had received a Ph.D. in algebraic geometry from Purdue in 1991. His adviser, T. T. Moh, with whom he parted unhappily, recently wrote a description on his Web site of Zhang as a graduate student: “When I looked into his eyes, I found a disturbing soul, a burning bush, an explorer who wanted to reach the North Pole.” Zhang left Purdue without Moh’s support, and, having published no papers, was unable to find an academic job. He lived, sometimes with friends, in Lexington, Kentucky, where he had occasional work, and in New York City, where he also had friends and occasional work. In Kentucky, he became involved with a group interested in Chinese democracy. Its slogan was “Freedom, Democracy, Rule of Law, and Pluralism.” A member of the group, a chemist in a lab, opened a Subway franchise as a means of raising money. “Since Tom was a genius at numbers,” another member of the group told me, “he was invited to help him.” Zhang kept the books. “Sometimes, if it was busy at the store, I helped with the cash register,” Zhang told me recently. “Even I knew how to make the sandwiches, but I didn’t do it so much.” When Zhang wasn’t working, he would go to the library at the University of Kentucky and read journals in algebraic geometry and number theory. “For years, I didn’t really keep up my dream in mathematics,” he said.
Posted by n2doc | Wed Jan 28, 2015, 07:50 PM (2 replies)
Scientists at Stanford University have found a way to program DNA in such a way that genes can be turned on or off in living cells. Incredibly, the new tool can affect two different genes at the same time, an advance that will allow scientists to treat even the most complex genetic disorders.
There are tens of thousands of genes in the human genome. Trouble is, nasty things can happen when even a single gene or gene sequence fails to activate, or if a deleterious mutated gene turns on. So how great would it be if we could find a way to enable or disable specific genes? A research team led by Stanford scientist Lei Stanley Qi has now figured this out.
In their new paper, which appears at the journal Cell, the geneticists describe a new system in which a kind of "programmable" genetic code can be used to selectively activate or deactivate genes. To do so, the scientists leveraged the power of the CRISPR/Cas9 gene editing system. But instead of using the "cut-and-paste" method of editing genes, the scientists rejigged the CRISPR molecule to include a second chunk of information on the RNA — a piece of information that tells the molecule to either boost or reduce a target gene's activity, or to just switch it on or off completely. By manipulating these genetic switches, the researchers have harnessed the power of genetic programming.
Posted by n2doc | Wed Jan 28, 2015, 06:34 PM (3 replies)
The Southern Poverty Law Center has filed a judicial ethics complaint against Alabama Supreme Court Chief Justice Roy Moore because of Moore's statements he intends to uphold the state's ban on same-sex marriage.
Moore made that assertion in a letter to Gov. Robert Bentley on Tuesday.
The letter was in response to the decision by U.S. District Judge Callie V.S. "Ginny" Granade striking down Alabama's Sanctity of Marriage Amendment, which was approved by voters in 2006.
Granade issued a stay on her order that is due to expire Feb. 9.
Read more: http://www.al.com/news/index.ssf/2015/01/southern_poverty_law_center.html
Posted by n2doc | Wed Jan 28, 2015, 05:45 PM (13 replies)
Like the gaping mouth of a gigantic celestial creature, the cometary globule CG4 glows menacingly in this new image from ESO’s Very Large Telescope. Although it appears to be big and bright in this picture, this is actually a faint nebula, which makes it very hard for amateur astronomers to spot. The exact nature of CG4 remains a mystery.
In 1976 several elongated comet-like objects were discovered on pictures taken with the UK Schmidt Telescope in Australia. Because of their appearance, they became known as cometary globules even though they have nothing in common with comets. They were all located in a huge patch of glowing gas called the Gum Nebula. They had dense, dark, dusty heads and long, faint tails, which were generally pointing away from the Vela supernova remnant located at the centre of the Gum Nebula. Although these objects are relatively close by, it took astronomers a long time to find them as they glow very dimly and are therefore hard to detect.
The object shown in this new picture, CG4, which is also sometimes referred to as God’s Hand, is one of these cometary globules. It is located about 1300 light-years from Earth in the constellation of Puppis (The Poop, or Stern).
The head of CG4, which is the part visible on this image and resembles the head of the gigantic beast, has a diameter of 1.5 light-years. The tail of the globule — which extends downwards and is not visible in the image — is about eight light-years long. By astronomical standards this makes it a comparatively small cloud.
Posted by n2doc | Wed Jan 28, 2015, 02:22 PM (3 replies)
Four crewmembers simulating a mission on Mars dealt with a real-life emergency late last month — a greenhouse fire so strong that flames reached at least 10 feet (3 meters) high.
On Dec. 29, the first day of their mission, the crew noticed an unusual power surge in their habitat at the Mars Desert Research Station (MDRS), in the Utah desert near the small town of Hanksville. A few minutes later, somebody spotted smoke coming from the greenhouse.
Crew commander Nick Orenstein, an experienced camper who has built bonfires in the past, ran outside to take a look. He said he figured the group could take on the fire, because the smoke was blowing away from the habitat, and only one shelf inside the greenhouse was aflame. At that time, the fire was about the size of three overstuffed chairs.
"This is a moment where instinct took over, the instinct of fight or flight, and we had fight," Orenstein told Space.com. "There really wasn't a question at the moment."
It took the crew about half an hour to bring the fire under control. Orenstein and crew engineer Dmitry Smirnov used all available fire extinguishers on site, but even after the extinguishers were exhausted and the power cut, the fire was still not out.
Posted by n2doc | Wed Jan 28, 2015, 02:17 PM (1 replies)
BY RACHEL AVIV
Stephen Torres was meeting with a client at his law office, in downtown Albuquerque, on April 12, 2011, when he received a call from a neighbor, who told him that police officers were aiming rifles at his house. He left work and drove to his home, in a middle-class suburb with a view of the mountains. There were more than forty police vehicles on his street. Officers wearing camouflage fatigues and bulletproof vests had circled his home, a sand-colored two-story house with a pitched tile roof. Two officers were driving a remote-controlled robot, used for discharging bombs, back and forth on the corner.
Stephen’s wife, Renetta, the director of human resources for the county, arrived a few minutes later, just after three o’clock. A colleague had heard her address repeated on the police radio, so her assistant pulled her out of a meeting. When Renetta saw that the street was cordoned off with police tape, she tried to walk to her house, but an officer told her that she couldn’t enter the “kill zone.” “What do you mean ‘kill zone’?” Renetta asked. “Ma’am, you can’t go any further,” the officer said.
Renetta and Stephen found each other at the southern end of the street. There were nearly eighty officers and city officials on the street, many of whom they recognized. Stephen saw a police-union attorney, who defended officers when they were in trouble. Renetta saw the city’s attorney, who worked in the same building and on the same floor as she did, and the deputy chief of police, whom she’d known in graduate school. “I kept looking her way, but she would not make eye contact with me,” Renetta said.
Renetta knew that the only person at home was the youngest of her three boys, Christopher, who was twenty-seven and had schizophrenia. Two hours earlier, he had stopped by her office for lunch, as he did a few times a week. Then he visited an elderly couple who lived two houses away. He said that he needed to “check up on them”; he often cleaned their pool or drove them to the grocery store. Because he found it overwhelming to spend too much time among people, he tried to do small, social errands, so as not to isolate himself.
Posted by n2doc | Wed Jan 28, 2015, 01:48 PM (4 replies)