Crocs Uncover

Bizarre Species

miércoles, 22 de diciembre de 2010

Universe's Most Massive Stars Can Form in Near Isolation, New Study Finds


Left: Star 302, as viewed from the ground. Right: Star 302 as viewed through the Hubble Space Telescope, which can zoom in roughly 40 times closer. From the ground, everything within the circle appears to be one star. (Credit: Courtesy of Joel Lamb)

New observations by University of Michigan astronomers add weight to the theory that the most massive stars in the universe could form essentially anywhere, including in near isolation; they don't need a large stellar cluster nursery.
This is the most detailed observational study to date of massive stars that appear (from the ground) to be alone. The scientists used the Hubble Space Telescope to zoom in on eight of these giants, which range from 20 to 150 times as massive as the Sun. The stars they looked at are in the Small Magellanic Cloud, a dwarf galaxy that's one of the Milky Way's nearest neighbors.

Their results, published in the Dec. 20 edition of The Astrophysical Journal, show that five of the stars had no neighbors large enough for Hubble to discern. The remaining three appeared to be in tiny clusters of ten or fewer stars.

Doctoral student Joel Lamb and associate professor Sally Oey, both in the Department of Astronomy, explained the significance of their findings.

"My dad used to fish in a tiny pond on his grandma's farm," Lamb said. "One day he pulled out a giant largemouth bass. This was the biggest fish he's caught, and he's fished in a lot of big lakes. What we're looking at is analogous to this. We're asking: 'Can a small pond produce a giant fish? Does the size of the lake determine how big the fish is?' The lake in this case would be the cluster of stars.

"Our results show that you can, in fact, form big stars in small ponds."

The most massive stars direct the evolution of their galaxies. Their winds and radiation shape interstellar gas and promote the birth of new stars. Their violent supernovae explosions create all the heavy elements that are essential for life and the Earth. That's why astronomers want to understand how and where these giant stars form. There is currently a big debate about their origins, Oey said.

One theory is that the mass of a star depends on the size of the cluster in which it is born, and only a large star cluster could provide a dense enough source of gas and dust to bring about one of these massive stars. The opposing theory, and the one that this research supports, is that these monstrous stars can and do form more randomly across the universe -- including in isolation and in very small clusters.

"Our findings don't support the scenario that the maximum mass of a star in a cluster has to correlate with the size of the cluster," Oey said.

The researchers acknowledge the possibility that all of the stars they studied might not still be located in the neighborhood they were born in. Two of the stars they examined are known to be runaways that have been kicked out of their birth clusters. But in several cases, the astronomers found wisps of leftover gas nearby, strengthening the possibility that the stars are still in the isolated places where they formed.

The research is funded by NASA and the National Science Foundation.

Africa Has Two Elephant Species, Genetic Analysis Confirms


Contrary to the belief of many scientists (as well as many members of the public), new research confirms that Africa has two -- not one -- species of elephant. Scientists from Harvard Medical School, the University of Illinois, and the University of York in the United Kingdom used genetic analysis to prove that the African savanna elephant and the smaller African forest elephant have been largely separated for several million years.
The researchers, whose findings appear online in PLoS Biology, compared the DNA of modern elephants from Africa and Asia to DNA that they extracted from two extinct species: the woolly mammoth and the mastodon. Not only is this the first time that anyone has generated sequences for the mastodon nuclear genome, but it is also the first time that the Asian elephant, African forest elephant, African savanna elephant, the extinct woolly mammoth, and the extinct American mastodon have been looked at together.

"Experimentally, we had a major challenge to extract DNA sequences from two fossils -- mammoths and mastodons -- and line them up with DNA from modern elephants over hundreds of sections of the genome," says research scientist Nadin Rohland of the Department of Genetics at Harvard Medical School.

According to David Reich, associate professor in the same department, "The surprising finding is that forest and savanna elephants from Africa -- which some have argued are the same species -- are as distinct from each other as Asian elephants and mammoths."

Researchers only had DNA from a single elephant in each species, but had collected enough data from each genome to traverse millions of years of evolution to the time when elephants first diverged from each other.

"The divergence of the two species took place around the time of the divergence of the Asian elephant and woolly mammoths," says Professor Michi Hofreiter, who specializes in the study of ancient DNA in the Department of Biology at York. "The split between African savanna and forest elephants is almost as old as the split between humans and chimpanzees. This result amazed us all."

The possibility that the two might be separate species was first raised in 2001, but this is the most compelling scientific evidence so far that they are indeed distinct.

Previously, many naturalists believed that African savanna elephants and African forest elephants were two populations of the same species, despite the significant size differences. The savanna elephant has an average shoulder height of 3.5 meters whereas the forest elephant has an average shoulder height of 2.5 meters. The savanna elephant weighs between six and seven tons, roughly double the weight of the forest elephant.

DNA analysis revealed a wide range of genetic diversity within each species. The savanna elephant and woolly mammoth have very low genetic diversity, Asian elephants have medium diversity, and forest elephants have very high diversity. Researchers believe that this is due to varying levels of reproductive competition among males.

"We now have to treat the forest and savanna elephants as two different units for conservation purposes," says Alfred Roca, assistant professor in the Department of Animal Sciences at the University of Illinois. "Since 1950, all African elephants have been conserved as one species. Now that we know the forest and savanna elephants are two very distinctive animals, the forest elephant should become a bigger priority for conservation purposes."

This research was funded by the Max Planck Society and by a Burroughs Wellcome Career Development Award in Biomedical Science.

Crown Suggests Queen Arsinoë II Ruled Ancient Egypt as Female Pharaoh


Queen Arsinoë II in the Philae temple, Aswan, Egypt. (Credit: Photo by Maria Nilsson)
A unique queen's crown with ancient symbols combined with a new method of studying status in Egyptian reliefs forms the basis for a re-interpretation of historical developments in Egypt in the period following the death of Alexander the Great. A thesis from the University of Gothenburg (Sweden) argues that Queen Arsinoë II ruled ancient Egypt as a female pharaoh, predating Cleopatra by 200 years.
Researchers are largely agreed on Queen Arsinoë II's importance from the day that she was deified. She was put on a level with the ancient goddesses Isis and Hathor, and was still respected and honoured 200 years after her death when her better-known descendant Cleopatra wore the same crown. But the reasons behind Arsinoë's huge influence have been interpreted in many different ways.

Maria Nilsson has studied her historical importance by interpreting her personal crown and its ancient symbols. The crown, which has never been found but is depicted on statues and Egyptian reliefs, was created with the help of the powerful Egyptian priesthood to symbolise the qualities of the queen. The thesis questions the traditional royal line which excludes female regents, and defies some researchers' attempts to minimise Arsinoë's importance while she was still alive.

"My conclusion instead is that Arsinoë was a female pharaoh and high priestess who was equal to and ruled jointly with her brother and husband, and that she was deified during her actual lifetime," says Nilsson. "It was this combination of religion and politics that was behind her long-lived influence."

But it was not only Cleopatra who wanted to re-use Arsinoë's important and symbolic crown. Male descendants -- all named Ptolemy -- used her crown as a template when creating a new crown which they gave to the goddess Hathor to honour the domestic priesthood and so win its support when Egypt was gripped by civil war.

The thesis is clearly structured around the crown and includes its wider context in the reliefs. Nilsson paints an all-round picture of the queen, how she dressed, the gods she was depicted with, the titles she was given, and so on.

The source material comes from Egypt and can be used as a basis for understanding the country's political and religious development. At the same time, Nilsson paves the way for future studies of Egyptian crowns as symbols of power and status, and of the development of art in a more general sense.

"The creation of Queen Arsinoë's crown was just the beginning," she says.

Lost Civilization Under Persian Gulf?


Antique map of the Persian Gulf. (Credit: iStockphoto/Chad McDermott)

A once fertile landmass now submerged beneath the Persian Gulf may have been home to some of the earliest human populations outside Africa, according to an article published in Current Anthropology.

Jeffrey Rose, an archaeologist and researcher with the University of Birmingham in the U.K., says that the area in and around this "Persian Gulf Oasis" may have been host to humans for over 100,000 years before it was swallowed up by the Indian Ocean around 8,000 years ago. Rose's hypothesis introduces a "new and substantial cast of characters" to the human history of the Near East, and suggests that humans may have established permanent settlements in the region thousands of years before current migration models suppose.

In recent years, archaeologists have turned up evidence of a wave of human settlements along the shores of the Gulf dating to about 7,500 years ago. "Where before there had been but a handful of scattered hunting camps, suddenly, over 60 new archaeological sites appear virtually overnight," Rose said. "These settlements boast well-built, permanent stone houses, long-distance trade networks, elaborately decorated pottery, domesticated animals, and even evidence for one of the oldest boats in the world."

But how could such highly developed settlements pop up so quickly, with no precursor populations to be found in the archaeological record? Rose believes that evidence of those preceding populations is missing because it's under the Gulf.

"Perhaps it is no coincidence that the founding of such remarkably well developed communities along the shoreline corresponds with the flooding of the Persian Gulf basin around 8,000 years ago," Rose said. "These new colonists may have come from the heart of the Gulf, displaced by rising water levels that plunged the once fertile landscape beneath the waters of the Indian Ocean."

Historical sea level data show that, prior to the flood, the Gulf basin would have been above water beginning about 75,000 years ago. And it would have been an ideal refuge from the harsh deserts surrounding it, with fresh water supplied by the Tigris, Euphrates, Karun, and Wadi Baton Rivers, as well as by underground springs. When conditions were at their driest in the surrounding hinterlands, the Gulf Oasis would have been at its largest in terms of exposed land area. At its peak, the exposed basin would have been about the size of Great Britain, Rose says.

Evidence is also emerging that modern humans could have been in the region even before the oasis was above water. Recently discovered archaeological sites in Yemen and Oman have yielded a stone tool style that is distinct from the East African tradition. That raises the possibility that humans were established on the southern part of the Arabian Peninsula beginning as far back as 100,000 years ago or more, Rose says. That is far earlier than the estimates generated by several recent migration models, which place the first successful migration into Arabia between 50,000 and 70,000 years ago.

The Gulf Oasis would have been available to these early migrants, and would have provided "a sanctuary throughout the Ice Ages when much of the region was rendered uninhabitable due to hyperaridity," Rose said. "The presence of human groups in the oasis fundamentally alters our understanding of human emergence and cultural evolution in the ancient Near East."

It also hints that vital pieces of the human evolutionary puzzle may be hidden in the depths of the Persian Gulf.

viernes, 3 de diciembre de 2010

David and Salomon 2



But, adds Mazar, "you shouldn't seek to prove the text verbatim." And yet multitudes of archaeologists have made that very goal their life's work, beginning with the American scholar and godfather of biblical archaeology William Albright. Among Albright's protégés was the Israeli military titan, politician, and scholar Yigael Yadin. For Yadin and his contemporaries, the Bible was unassailable. As a result, when he uncovered the city gates at the biblical city of Hazor in the late 1950s, Yadin committed what would be a current-day archaeological no-no: Since carbon dating wasn't available, he used the Bible, along with the stratigraphy, to date the pottery found inside the gates. He attributed the gates to the exalted tenth-century B.C. empire of Solomon—because the First Book of Kings said so.

The problem with relying on this particular chapter of the Bible is that it was added long after Solomon died in 930 B.C., when Israel had split into two parts—Judah in the south and Israel in the north. "Gezer was the most southerly city in the northern kingdom of Israel, while Hazor was in the most northern realm, and Megiddo was an economic hub in the center," says Tel Aviv University archaeologist Norma Franklin. "So it would be important to the people writing this story to lay claim to all of this territory. To Yadin, the Bible said so and that was it. Three gates—they all have to be Solomon's."

Today, many scholars (including Franklin and her colleague Finkelstein) doubt that all three gates are Solomonic, while others (Amihai Mazar, for example) think they could be. But all of them reject Yadin's circular reasoning, which in the early 1980s helped spawn a backlash movement of "biblical minimalism," led by scholars at the University of Copenhagen. To the minimalists, David and Solomon were simply fictitious characters. The credibility of that position was undercut in 1993, when an excavation team in the northern Israel site of Tel Dan dug up a black basalt stela inscribed with the phrase "House of David." Solomon's existence, however, remains wholly unverified.

Absent more evidence, we're left with the decidedly drab tenth-century B.C. biblical world that Finkelstein first proposed in a 1996 paper—not a single great kingdom replete with monumental buildings but instead a scruffy landscape of disparate, slowly gelling powers: the Philistines to the south, Moabites to the east, Israelites to the north, Aramaeans farther north, and yes, perhaps, a Judaean insurgency led by a young shepherd in not-so-dazzling Jerusalem. Such an interpretation galls Israelis who regard David's capital as their bedrock. Many of the excavations undertaken in Jerusalem are financially backed by the City of David Foundation, whose director of international development, Doron Spielman, freely admits, "When we raise money for a dig, what inspires us is to uncover the Bible—and that's indelibly linked with sovereignty in Israel."
Unsurprisingly, this agenda does not sit well with the Jerusalem residents who happen to be Palestinian. Many excavations take place in the eastern part of the city, where their families have dwelled for generations but stand to be displaced if such projects morph into Israeli settlement claims. From the Palestinian perspective, the scurrying for archaeological evidence to justify a people's sense of belonging misses the point. As East Jerusalem resident and archaeology professor Hani Nur el-Din says, "When I see Palestinian women making the traditional pottery from the early Bronze Age, when I smell the taboon bread baked in the same tradition as the fourth or fifth millennium B.C., this is the cultural DNA. In Palestine there's no written document, no historicity—but still, it's history."

Most Israeli archaeologists would prefer that their work not be used as a political wedge. This, nonetheless, is the way of young nations. As Bar-Ilan University archaeology professor Avraham Faust observes, "The Norwegians relied on Viking sites to create a separate identity from their Swedish and Danish rulers. Zimbabwe is named after an archaeological site. Archaeology is a very convenient tool for creating national identities."

That is one way in which Israel differs from other countries. Its national identity came well before any digging. What's dug up can only confirm that identity … or not.

"This place was hell," says Tom Levy cheerfully as he stands over an open pit filled with ancient coal-black slag. Sprawling around him and his volunteer undergraduates from the University of California, San Diego is a 25-acre copper production site—and adjacent to it, a large fortress complex that includes the ruins of 3,000-year-old guardhouses. Apparently the sentinels lived practically on top of the smelting operations, while overseeing a presumably reluctant labor force. "When you have industrial production of this scale, you have to have a procurement system for food and water," Levy continues. "I can't prove it, but I think that the only people that are going to be working in this rather miserable environment are either slaves—or undergrads. The point is, simple tribal societies couldn't do something like this."
Levy, an anthropologist, first came to southern Jordan in 1997 to examine metallurgy's role in social evolution. The lowland district of Faynan, where the blue-green glitter of malachite can be seen from a distance, was an obvious place to study. It also happened to be where the American rabbi and archaeologist Nelson Glueck unabashedly proclaimed in 1940 that he had discovered the Edomite mines controlled by King Solomon. Subsequent British excavators believed they had found evidence that Glueck was off by some three centuries and that Edom actually dated to the seventh century B.C. But when Levy started probing the site known as Khirbat en Nahas (Arabic for "ruins of copper"), the samples he sent off to Oxford for radiocarbon dating confirmed that Glueck had been on the right track: This was a tenth-century copper-production site—and, Levy adds pointedly, "the closest copper source to Jerusalem."

The team headed by Levy and his Jordanian colleague Mohammad Najjar has uncovered a four-chambered gate similar to ones found at sites in Israel that might date to the tenth-century B.C. A few miles from the mines, they've excavated a cemetery of more than 3,500 tombs dating to the same period—perhaps filled with the remains of Iron Age mountain nomads known from ancient Egyptian sources as Shasu, who Levy thinks may have been "corralled at certain points in time and forced to work in the mines." Most work in the mines appears to have ceased by the end of the ninth century—and the so-called "disruption layer" uncovered by Levy's students may explain why.

They found in this layer 22 date pits, which they dated to the tenth century B.C., along with Egyptian artifacts such as a lion-headed amulet and a scarab, both from the time of the pharaoh Shoshenq I. That ruler's invasion of the region shortly after Solomon's death is chronicled in the Old Testament and at the Temple of Amun at Karnak. "I definitely believe that Shoshenq disrupted metal production here at the end of the tenth century," says Levy. "The Egyptians in the Third Intermediate Period weren't strong enough to field an occupying force, which is why you don't see Egyptian bread molds and other material culture here. But they could organize some pretty big military campaigns—strong enough to upset these petty kingdoms, to make sure they wouldn't be a threat to them. That's what I think Shoshenq did here."


The "hell" that Levy has unearthed at Khir­bat en Nahas could prove to be hell for the Finkelstein school of low chronology. Levy's copper mines may not be as sexy as King David's palace or the perch overlooking the battle of David and Goliath. But Levy's excavation work spans more time and area than those of Eilat Mazar and Yosef Garfinkel, with far more extensive use of radiocarbon analysis to determine the age of his site's stratigraphic layers. "All scholars dealing with Edom in the last two generations claimed that Edom didn't exist as a state before the eighth century B.C.," says Amihai Mazar. "But Levy's radiocarbon dates have their own story, and that story is related to the tenth to ninth century B.C., and no one can claim that they're incorrect."

In fact, that is precisely what Levy's critics are doing. Some deemed his first 46 datings insufficient to justify reordering an entire chronology for Edom. For his second round of C-14 analysis, Levy doubled the number of samples and meticulously selected charcoal from shrubs with verifiable outer growth rings.

Despite the high cost of C-14 analysis—more than $500 for a single olive pit—the technique isn't a silver bullet. "Carbon-14 doesn't help you solve all this controversy," says Eilat Mazar. "You have the plus or minus"—a margin of error of about 40 years. "You have different laboratories bringing different interpretations. You have debates about the whole C-14 issue." Indeed, Finkelstein and Amihai Mazar have been locked in an ongoing tussle over the dating of a single stratum at Tel Rehov, a Bronze and Iron Age city just west of the Jordan River. Mazar contends that the stratum could be Solomonic. Finkelstein says it's from the later Omride dynasty, named for Omri, Ahab's father. The gap between the two eras is about 40 years.

"Many of the radiocarbon dates for this period cover exactly the range that's under debate," Amihai Mazar says, chuckling wearily. "Not before and not after. It's been this way for 15 years."

"You can find evidence in radiocarbon for David being a villager in Norway in the sixth century A.D.!" declares Israel Finkelstein—exaggerating to make a point, as he is prone to doing. "But look, I enjoy reading everything Tom writes about Khirbat en Nahas. It has brought all sorts of ideas to me. I myself would never dig in such a place—too hot! For me, archaeology is about having a good time. You should come to Megiddo—we live in an air-conditioned B&B next to a nice swimming pool."
This is how Finkelstein begins his rebuttals, with amiable preambles that cannot conceal the Mephisto-like gleam in his eyes. For a scholar, the Tel Aviv archaeologist has a highly visceral manner—leaning his tall, bearded frame into a visitor's face, waving his large hands, modulating his baritone with Shakespearean agility.

Yet his charm wears thin for those who have felt the sting of his attacks. "If you want to attract attention, you behave like Finkelstein," says Eilat Mazar. Similarly unamused is Yosef Garfinkel, who says of Finkelstein's recent receipt of a four-million-dollar research grant, "He doesn't even use science—that's the irony. It's like giving Saddam Hussein the Nobel Peace Prize."

Still, Finkelstein's theories strike an intellectually appealing middle ground between biblical literalists and minimalists. "Think of the Bible the way you would a stratified archaeological site," he says. "Some of it was written in the eighth century B.C., some the seventh, and then going all the way to the second B.C. So 600 years of compilation. This doesn't mean that the story doesn't come from antiquity. But the reality presented in the story is a later reality. David, for example, is a historical figure. He did live in the tenth century B.C. I accept the descriptions of David as some sort of leader of an upheaval group, troublemakers who lived on the margins of society. But not the golden city of Jerusalem, not the description of a great empire in the time of Solomon. When the authors of the text describe that, they have in their eyes the reality of their own time, the Assyrian Empire.

"Now, Solomon," he continues with a sigh. "I think I destroyed Solomon, so to speak. Sorry for that! But take Solomon, dissect it. Take the great visit of the Queen of Sheba—an Arabian queen coming to visit, bringing all sorts of exotic commodities to Jerusalem. This is a story which is an impossibility to think about before 732 B.C., before the beginning of Arabian trade under Assyrian domination. Take the story of Solomon as the great, you know, trainer in horses and chariots and big armies and so on. The world behind Solomon is the world of the Assyrian century."

Of Levy's mining fortress, Finkelstein says, "I don't buy that it's from the tenth century B.C. There's no way people lived on this site during production. The fire, the toxic fumes—forget it! Instead, look at the fortress of En Hazeva on our side of the Jordan River, built by the Assyrians on the main road to Edom. I see Tom's building as an eighth-century Assyrian fortress parallel to the other one. And look, at the end of the day, his is a marginal site. It's not a stratified city with many eras, like Megiddo and Tel Rehov. Taking a pile of slag and making it the center of the discussion of biblical history—forget it, no way, I reject this absolutely!"



With greater venom, Finkelstein mocks Garfinkel's discoveries at Khirbet Qeiyafa: "Look, you'll never catch me saying, 'I've found one olive pit at a stratum in Megiddo, and this olive pit—which goes against hundreds of carbon-14 determinations—is going to decide the fate of Western civilization.' " He snickers. The lack of pig bones, suggesting it is a Judaean site? "A gun, but not a smoking gun." The rare inscription found at the site? Probably from Philistine Gath rather than the kingdom of Judah.

The irony is that biblical archaeology's enfant terrible has become the establishment, a Goliath fending off upstart assaults on his chronological order. The proposition that a complex tenth-century B.C. society may have existed on either side of the Jordan River has thrown Finkelstein's vision of the David and Solomon era squarely on the defensive. His many rebuttal papers and his sarcastic tone reflect that defensiveness, and his arguments at times seem a bit desperate. (The notion of living in a fortress next to a copper-smelting site would not seem ludicrous to West Virginia coal miners or residents near Three Mile Island, for example.)

Still, even if Garfinkel can prove that the Judah tribe that begat David dwelled in the fortress of Shaaraim, and Eilat Mazar can document that King David commissioned a palace in Jerusalem, and Tom Levy can successfully demonstrate that King Solomon oversaw copper mines in Edom, this does not a glorious biblical dynasty make. How much digging before the argument is settled?

Many archaeologists question whether the obsessive scramble to prove the biblical narrative is a healthy enterprise. One of them, Tel Aviv University's Raphael Greenberg, flatly states, "It's bad for archaeology. What we're supposed to contribute is a point of view that isn't available from texts or preconceived notions of history—an alternative vision of the past: relations between rich and poor, between men and women. Something richer, in other words, than just validating the Bible."

But does David, with all of his metaphorical power, cease to matter if his deeds and his empire are ultimately viewed as works of fiction? When I point out to Finkelstein that people all over the world are invested in the greatness of David, I am surprised by his response. "Look, when I'm doing research, I have to distinguish between the culture of David and the historical David. David is extremely important for my cultural identity. In the same way, I can cele­brate the Exodus without seeing it as a purely historic event. David for me is the David reflected in the later king Hezekiah, the David reflected in the later king Josiah, the David of Zacharias in the eschatological prophesies in which Jerusalem is burned but David is alive, the David who is the connection with the beginning of Christianity. In this sense, David is everything. If you want me to say it simplistically, I'm proud that this nobody from nowhere became the center of Western tradition.

"So for me," says Finkelstein, David's dethroner, "David is not a plaque on the wall, not even merely a leader of a tenth-century band. No. Much more than that."

David and Solomon 1


The woman sitting on a bench in the Old City of Jerusalem, round-faced and bundled up against the autumn chill, chews on an apple while studying the building that has brought her both fame and aggravation. It doesn't really look like a building—just some low stone walls abutting an ancient terraced retaining wall 60 feet high. But because the woman is an archaeologist, and because this is her discovery, her eyes see what others might not. She sees the building's position, on a northern escarpment of the ancient city overlooking Jerusalem's Kidron Valley, and she imagines an ideal perch from which to survey a kingdom. She imagines the Phoenician carpenters and stonemasons who erected it in the tenth century B.C. She imagines as well the Babylonians who destroyed it four centuries later. Most of all, she imagines the man she believes commissioned and occupied the building. His name was David. This, she has declared to the world, is most likely the building described in the Second Book of Samuel: "King Hiram of Tyre sent … carpenters and masons, and they built a house for David. And David realized that the Lord had established him as king over Israel, and that He had exalted his kingdom for the sake of His people Israel."

The woman's name is Eilat Mazar. Munching and gazing, she is the picture of equanimity—until a tour guide shows up. He's a young Israeli man accompanied by a half dozen tourists who assemble in front of the bench so they can view the building. The moment he opens his mouth, Mazar knows what's coming. The tour guide is a former archaeology student of hers. She's heard how he brings tourists to this spot and informs them that this is NOT the palace of David and that all the archaeological work at the City of David is a way for right-wing Israelis to expand the country's territorial claims and displace Palestinians.

Mazar jumps up from the bench and marches over to the tour guide. She chews him out in a staccato of Hebrew, while he stares passively at her. The gaping tourists watch her stalk off.

"You really need to be strong," she mutters as she walks. "It's like everyone wants to destroy what you do." And then, more plaintively: "Why? What did we do wrong?"

The archaeologist gets into her car. She looks stricken. "I feel like I'm really getting sick from stress," she says. "I've lost years from my life."

In no other part of the world does archaeology so closely resemble a contact sport. Eilat Mazar is one of the reasons why. Her announcement in 2005 that she believed she had unearthed the palace of King David amounted to a ringing defense of an old-school proposition under assault for more than a quarter century—namely, that the Bible's depiction of the empire established under David and continued by his son Solomon is historically accurate. Mazar's claim has emboldened those Christians and Jews throughout the world who maintain that the Old Testament can and should be taken literally. Her purported discovery carries particular resonance in Israel, where the story of David and Solomon is interwoven with the Jews' historical claims to biblical Zion.

That narrative is familiar to any student of the Bible. A young shepherd named David from the tribe of Judah slays the giant Goliath from the enemy tribe of the Philistines, is elevated to king of Judah following the death of Saul at the close of the 11th century B.C., conquers Jerusalem, unites the people of Judah with the disparate Israelite tribes to the north, and thereupon amasses a royal dynasty that continues with Solomon well into the tenth century B.C. But while the Bible says David and Solomon built the kingdom of Israel into a powerful and prestigious empire stretching from the Mediterranean to the Jordan River, from Damascus to the Negev, there's a slight problem—namely, that despite decades of searching, archaeologists had found no solid evidence that David or Solomon ever built anything.

Then Mazar sounded her trumpet. "She knew what she was doing," says fellow Israeli archaeologist David Ilan of Hebrew Union College. "She waded into the fray purposefully, wanting to make a statement."

Ilan himself doubts that Mazar has found King David's palace. "My gut tells me this is an eighth- or ninth-century building," he says, constructed a hundred years or more after Solomon died in 930 B.C. More broadly, critics question Mazar's motives. They note that her excavation work was underwritten by two organizations—the City of David Foundation and the Shalem Center—dedicated to the assertion of Israel's territorial rights. And they scoff at Mazar's allegiance to the antiquated methods of her archaeological forebears, such as her grandfather, who unapologetically worked with a trowel in one hand and the Bible in the other.

The once common practice of using the Bible as an archaeological guide has been widely contested as an unscientific case of circular reasoning—and with particular relish by Tel Aviv University's contrarian-in-residence Israel Finkelstein, who has made a career out of merrily demolishing such assumptions. He and other proponents of "low chronology" say that the weight of archaeological evidence in and around Israel suggests that the dates posited by biblical scholars are a century off. The "Solomonic" buildings excavated by biblical archaeologists over the past several decades at Hazor, Gezer, and Megiddo were not constructed in David and Solomon's time, he says, and so must have been built by kings of the ninth-century B.C.'s Omride dynasty, well after David and Solomon's reign.

During David's time, as Finkelstein casts it, Jerusalem was little more than a "hill-country village," David himself a raggedy upstart akin to Pancho Villa, and his legion of followers more like "500 people with sticks in their hands shouting and cursing and spitting—not the stuff of great armies of chariots described in the text.

"Of course we're not looking at the palace of David!" Finkelstein roars at the very mention of Mazar's discovery. "I mean, come on. I respect her efforts. I like her—very nice lady. But this interpretation is—how to say it?—a bit naive."
Now it is Finkelstein's theory that is under siege. On the heels of Mazar's claim to have discovered King David's palace, two other archaeologists have unveiled remarkable finds. Twenty miles southwest of Jerusalem in the Elah Valley—the very spot where the Bible says the young shepherd David slew Goliath—Hebrew University professor Yosef Garfinkel claims to have unearthed the first corner of a Judaean city dating to the exact time that David reigned. Meanwhile, 30 miles south of the Dead Sea in Jordan, a University of California, San Diego professor named Thomas Levy has spent the past eight years excavating a vast copper-smelting operation at Khirbat en Nahas. Levy dates one of the biggest periods of copper production at the site to the tenth century B.C.—which, according to the biblical narrative, is when David's antagonists the Edomites dwelled in this region. (However, scholars like Finkelstein maintain that Edom did not emerge until two centuries later.) The very existence of a large mining and smelting operation fully two centuries before Finkelstein's camp maintains the Edomites emerged would imply complex economic activity at the exact time that David and Solomon reigned. "It's possible that this belonged to David and Solomon," Levy says of his discovery. "I mean, the scale of metal production here is that of an ancient state or kingdom."

Levy and Garfinkel—both of whom have been awarded grants by the National Geographic Society—support their contentions with a host of scientific data, including pottery remnants and radiocarbon dating of olive and date pits found at the sites. If the evidence from their ongoing excavations holds up, yesteryear's scholars who touted the Bible as a factually accurate account of the David and Solomon story may be vindicated.

As Eilat Mazar says with palpable satisfaction, "This is the end of Finkelstein's school."

A busy highway, Route 38, crosses the ancient road that follows the Elah Valley en route to the Mediterranean Sea. Beneath the hills on either side of the road lie the ruins of Socoh and Azekah. According to the Bible, the Philistines encamped in this valley, between the two towns, just before their fateful encounter with David.

The battlefield of legend is now quiet and abounds with wheat, barley, almond trees, and grapevines, not to mention a few of the indigenous terebinth (elah in Hebrew) trees from which the valley derives its name. A small bridge extends from Route 38 over the Brook of Elah. During high season, tourist buses park here so that their passengers can climb down into the valley and retrieve a rock to take back home and impress friends with a stone from the same place as the one that killed Goliath.

"Maybe Goliath never existed," says Garfinkel as he drives across the bridge and up to his site, Khirbet Qeiyafa. "The story is that Goliath came from a giant city, and in the telling of it over the centuries, he became a giant himself. It's a metaphor. Modern scholars want the Bible to be like the Oxford Encyclopedia. People didn't write history 3,000 years ago like this. In the evening by the fire, this is where stories like David and Goliath started."

Beneath Garfinkel's bald, scholarly exterior and gentle sense of humor—which reveals a jagged edge when the subject is Israel Finkelstein—lurks a man of unmistakable ambition. He first learned from an Israeli Antiquities Authority ranger about a nine-foot-high megalithic wall looming over the Brook of Elah. He began digging in earnest in 2008.

The wall, Garfinkel discovered, was of the same variety seen in the northern cities of Hazor and Gezer—a casemate of two walls with a chamber in between—and it encircled a fortified city of about six acres. Private houses abutted the city wall, an arrangement not seen in Philistine society. After shoveling out the topsoil, Garfinkel uncovered coins and other artifacts from the time of Alexander the Great. Beneath that Hellenistic layer he found buildings scattered with four olive pits, which carbon-14 analysis dated to around 1000 B.C. He also found an ancient tray for baking pita bread, along with hundreds of bones from cattle, goats, sheep, and fish—but no pig bones. In other words, Judaeans, rather than Philistines, must have lived (or at least dined) here. Because Garfinkel's excavation team also uncovered a very rare find—a clay pottery sherd with writing that appears to be a proto-Canaanite script with verbs characteristic of Hebrew—the conclusion to him seemed obvious: Here was a tenth-century B.C. complex Judaean society of the sort that low chronologists like Finkelstein claimed did not exist.

And what was its name? Garfinkel found his answer upon discovering that the fortified city had not one but two gates—the only such site found thus far in the kingdoms of Judah and Israel. "Two gates" translates into Hebrew as shaarayim, a city mentioned three times in the Bible. One of those references (I Samuel 17:52) describes the Philistines fleeing David back to Gath via the "road from Shaaraim."

"You have David and Goliath, and you have our site, and it fits," says Garfinkel simply. "It's typical Judaea, from the animal bones to the city wall. Give us two arguments why this is Philistine. One argument is because Finkelstein doesn't want us to destroy low chronology. OK, so give us a second reason."
Here would be a second reason to be skeptical of Yossi Garfinkel's conclusions: He announced them, swiftly and dramatically, despite the fact that he had only four olive pits on which to base his dating, a single inscription of a highly ambiguous nature, and a mere 5 percent of his site excavated. In other words, says archaeologist David Ilan, "Yossi has an agenda—partly ideological, but also personal. He's a very smart and ambitious guy. Finkelstein's the big gorilla, and the young bucks think he's got a monopoly over biblical archaeology. So they want to dethrone him."

Better still, from the perspective of other interested parties: Once Finkelstein retreats from the throne, King David returns to it.

He has persisted for three millennia—an omnipresence in art, folklore, churches, and census rolls. To Muslims, he is Daoud, the venerated emperor and servant of Allah. To Christians, he is the natural and spiritual ancestor of Jesus, who thereby inherits David's messianic mantle. To the Jews, he is the father of Israel—the shepherd king anointed by God—and they in turn are his descendants and God's Chosen People. That he might be something lesser, or a myth altogether, is to many unthinkable.

"Our claim to being one of the senior nations in the world, to being a real player in civilization's realm of ideas, is that we wrote this book of books, the Bible," says Daniel Polisar, president of the Shalem Center, the Israeli research institute that helped fund Eilat Mazar's excavation work. "You take David and his kingdom out of the book, and you have a different book. The narrative is no longer a historical work, but a work of fiction. And then the rest of the Bible is just a propagandistic effort to create something that never was. And if you can't find the evidence for it, then it probably didn't happen. That's why the stakes are so high."

The books of the Old Testament outlining the story of David and Solomon consist of scriptures probably written at least 300 years after the fact, by not-so-objective authors. No contemporaneous texts exist to validate their claims. Since the dawn of biblical archaeology, scholars have sought in vain to verify that there really was an Abraham, a Moses, an Exodus, a conquest of Jericho. At the same time, says Amihai Mazar, Eilat's cousin and among Israel's most highly regarded archaeologists, "Almost everyone agrees that the Bible is an ancient text relating to the history of this country during the Iron Age. You can look at it critically, as many scholars do. But you can't ignore the text—you must relate to it."

Cleopatra Not First Female Pharoah of Her Line


* A study into a unique Egyptian crown suggests that Queen Arsinoë II ruled Egypt as pharaoh.
* Arsinoë II had a life marked by dynastic murders, intrigue, sex and greed.
* Her crown was so special that it was later worn by Cleopatra and also used as a template by male descendants.


Cleopatra may not have been ancient Egypt's only female pharaoh of the Ptolemaic dynasty -- Queen Arsinoë II, a woman who competed in and won Olympic events, came first, some 200 years earlier, according to a new study into a unique Egyptian crown.

After analyzing details and symbols of the crown worn by Arsinoë and reinterpreting Egyptian reliefs, Swedish researchers are questioning Egypt's traditional male-dominated royal line. They suggest that Queen Arsinoë II (316-270 B.C.) was the first female pharaoh belonging to Ptolemy's family -- the dynasty that ruled Egypt for some 300 years until the Roman conquest of 30 B.C.

While researchers largely agree on Arsinoë's prominence -- she was deified during her lifetime and honored for 200 years after her death -- the new study suggests she was in fact an Egyptian pharaoh with a role similar to the more famous Hatshepsut and Cleopatra VII.

One of the great women of the ancient world, Arsinoë was the daughter of Ptolemy I (366–283 B.C.), a Macedonian general under Alexander the Great who later became ruler of Egypt and founder of the Ptolemaic dynasty to which Cleopatra belonged.

With a life marked by dynastic murders, intrigue, sex and greed, Arsinoë may have been the most outstanding of Cleopatra's female predecessors.

"She was no ordinary woman. She fought in battles, and even participated in the Olympics, where she won three events for harnessed horses," Maria Nilsson, from the University of Gothenburg, told Discovery News.

Married at the age of 16 to Lysimachus of Thrace, a 60-year-old general of Ptolemy I, Arsinoë earned great wealth and honors during her time in Greece.

When, 18 years later, Lysimachus died, she married her half-brother, Ptolemy Keraunus. The marriage then ended abruptly after Keraunus killed two of Arsinoë's three sons.

Arsinoë then returned to Egypt and married her brother King Ptolemy II, her junior by eight years.

A crown, which has never been found, but is depicted on statues and carved stone reliefs, was created especially for her.

Nilsson analyzed 158 Egyptian relief scenes dating from Arsinoë's lifetime to Emperor Trajan, spanning about 400 years, studying every detail of the crown, including hieroglyphic titles and relief scenes.

She found that the crown differed from the usual Egyptian royal headdress such as the khepresh (or blue crown), the white crown, the red crown, the double crown, the double feather plume and atef (or ostrich feather) crown.

Instead, it was made of four main elements: the red crown, symbolizing the rule of Lower Egypt, the ram horns, connected primarily with the ram god of Egypt, Amon, the cow horns and solar disc, symbolizing the goddess Hathor and the harmony between male and female, and the double feather plume, another important symbol of Amon.

According to Nilsson, these symbols show that Arsinoë's crown was created for a living queen who was supposed to be a high priestess, a goddess and the ruler of Lower Egypt at the same time.

"It means that she was proclaimed female pharaoh during her lifetime. She co-ruled Egypt, as the king of Lower Egypt, with her brother-husband Ptolemy II, king of Upper Egypt," Nilsson said.

Put on a level with the ancient goddesses Isis and Hathor, Arsinoë was considered a god during her lifetime and was honored for 200 years after her death at 45. A special shrine, the Arsinoëion, was built in her honor at Alexandria, and a festival, the Arsinoëia, was created for her.

Found in at least 27 variations, Arsinoë's symbolic crown was later worn by Ptolemaic queens Cleopatra III and Cleopatra VII and also used as a template by several male Ptolemy descendants.

"This profound study opens a new field of research and shows that the other Ptolemaic queens, especially the Cleopatras, tended to imitate Arsinoë II in their iconographic elements," Mona Haggag, professor of classical archaeology at Alexandria University, Egypt, told Discovery News.

According to Carole Gillis, associate professor at the department of archaeology and ancient history at Lund University, Sweden, the study is important as it reveals that the Queen wore the crown in her own lifetime, in public view, with its symbols clearly understandable for everyone.

Ancient Mega-Lake Found in Egyptian Desert


* A mega-lake in today's hyper-arid western Egypt might have been fed by the earliest Nile floods.
* The discovery helps explain fish fossils in the desert.
* An alternative hypothesis is that the mega-lake fed the Nile, not the other way around.

The hyper-arid deserts of western Egypt were once home to a lush mega-lake fed by the Nile River's earliest annual floods.

Fossil fish and space shuttle radar images have defined the bed and drainage channels of the long lost lake, which at times was larger than Lake Michigan, stretching as far as 250 miles west of the Nile in southwestern Egypt.

The discovery pushes back the origin of the "Gift of the Nile" floods to more than a quarter million years ago and paints a drastically different picture of Egypt's environment than is seen today. It also explains the longstanding puzzle of the fossilized fish found in the desert -- fish that are of the same kinds that live in today's Nile River.

It took a lot of staring at the high-resolution radar topographic maps from the 1980s and 1990s -- and tinkering with the colors of those maps -- to make sense of it all.

"It just struck me that: 'Hey, maybe that was the level for the lake,'" said Ted Maxwell of the Smithsonian Institution's Center for Earth and Planetary Studies.

Although the topography is compelling, the evidence by itself isn't sufficient to prove a lake was there or how it was created.

For one thing, there needs to be a source for all the water. That would likely have been Wadi Tushka, a pass to the west of the Nile, which is low enough for the Nile River to have flooded through provided there was more rainfall and larger annual floods than are known today.

Then there are the fish fossils, which are unmistakable evidence for there having been Nile-related water water filling the basin.

There are also archeological sites, said Maxwell, that help to roughly confine the dates of the lake's surface elevation in more recent times. Maxwell and his coauthors Bahay Issawi and C. Vance Haynes, Jr., published their study in the December issue of the journal Geology.

Despite the radar maps, fish and archeology, however, there is a lot of evidence that should be there, but isn't, said Maxwell.

Take the old shorelines, or "bathtub rings," that are often the definitive evidence of long-lost mega-lakes of wetter times in other parts of the world, including in Utah, Nevada and California. In Egypt those shorelines have probably been sandblasted away over the millennia by scouring winds, Maxwell said.

And what about some distinctively lake-formed sediments in the basin itself?

"The problem is there is no sedimentary evidence," Maxwell told Discovery News. And so the mega-lake is harder to prove than most.

Despite this, other researchers looking at the area find there are more reasons for believing that a long lineage of great lakes filled the basin that might not have needed the Nile as their source.

"Other possibilities for the source of the water include drainage from the highlands to the west, groundwater recharge from the south, and local rains, potentially from different directions and sources," said researcher Christopher Hill of Boise State University.

The older sedimentary remnants associated with springs and archeological artifacts seem to point to local rains or groundwater creating lakes that were smaller and smaller over time and not from the Nile, said Hill. Those sources could have, perhaps, enlarged the lake enough to join and flow into the the Nile and allow the fish to move upstream into the lake, without Nile flooding. That would mean the water at Wadi Tushka would have been flowing east into the Nile rather than west into the lake.

In other words, the lake certainly existed, but the jury is still out on how it got there.

Life Built With Toxic Chemical: First Known Microbe on Earth Able to Thrive and Reproduce Using Arsenic


NASA-funded astrobiology research has changed the fundamental knowledge about what comprises all known life on Earth.Researchers conducting tests in the harsh environment of Mono Lake in California have discovered the first known microorganism on Earth able to thrive and reproduce using the toxic chemical arsenic. The microorganism substitutes arsenic for phosphorus in its cell components.

"The definition of life has just expanded," said Ed Weiler, NASA's associate administrator for the Science Mission Directorate at the agency's Headquarters in Washington. "As we pursue our efforts to seek signs of life in the solar system, we have to think more broadly, more diversely and consider life as we do not know it."

This finding of an alternative biochemistry makeup will alter biology textbooks and expand the scope of the search for life beyond Earth. The research is published in this week's edition of Science Express.

Carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur are the six basic building blocks of all known forms of life on Earth. Phosphorus is part of the chemical backbone of DNA and RNA, the structures that carry genetic instructions for life, and is considered an essential element for all living cells.

Phosphorus is a central component of the energy-carrying molecule in all cells (adenosine triphosphate) and also the phospholipids that form all cell membranes. Arsenic, which is chemically similar to phosphorus, is poisonous for most life on Earth. Arsenic disrupts metabolic pathways because chemically it behaves similarly to phosphate.

"We know that some microbes can breathe arsenic, but what we've found is a microbe doing something new -- building parts of itself out of arsenic," said Felisa Wolfe-Simon, a NASA Astrobiology Research Fellow in residence at the U.S. Geological Survey in Menlo Park, Calif., and the research team's lead scientist. "If something here on Earth can do something so unexpected, what else can life do that we haven't seen yet?"

The newly discovered microbe, strain GFAJ-1, is a member of a common group of bacteria, the Gammaproteobacteria. In the laboratory, the researchers successfully grew microbes from the lake on a diet that was very lean on phosphorus, but included generous helpings of arsenic. When researchers removed the phosphorus and replaced it with arsenic the microbes continued to grow. Subsequent analyses indicated that the arsenic was being used to produce the building blocks of new GFAJ-1 cells.

The key issue the researchers investigated was when the microbe was grown on arsenic did the arsenic actually became incorporated into the organisms' vital biochemical machinery, such as DNA, proteins and the cell membranes. A variety of sophisticated laboratory techniques was used to determine where the arsenic was incorporated.

The team chose to explore Mono Lake because of its unusual chemistry, especially its high salinity, high alkalinity, and high levels of arsenic. This chemistry is in part a result of Mono Lake's isolation from its sources of fresh water for 50 years.

The results of this study will inform ongoing research in many areas, including the study of Earth's evolution, organic chemistry, biogeochemical cycles, disease mitigation and Earth system research. These findings also will open up new frontiers in microbiology and other areas of research.

"The idea of alternative biochemistries for life is common in science fiction," said Carl Pilcher, director of the NASA Astrobiology Institute at the agency's Ames Research Center in Moffett Field, Calif. "Until now a life form using arsenic as a building block was only theoretical, but now we know such life exists in Mono Lake."

The research team included scientists from the U.S. Geological Survey, Arizona State University in Tempe, Ariz., Lawrence Livermore National Laboratory in Livermore, Calif., Duquesne University in Pittsburgh, Penn., and the Stanford Synchroton Radiation Lightsource in Menlo Park, Calif.

NASA's Astrobiology Program in Washington contributed funding for the research through its Exobiology and Evolutionary Biology program and the NASA Astrobiology Institute. NASA's Astrobiology Program supports research into the origin, evolution, distribution, and future of life on Earth.

For more information about the finding and a complete list of researchers, visit: http://astrobiology.nasa.gov

Breakthrough Chip Technology Lights Path to Exascale Computing: Optical Signals Connect Chips Together Faster and With Lower Power


IBM scientists have unveiled a new chip technology that integrates electrical and optical devices on the same piece of silicon, enabling computer chips to communicate using pulses of light (instead of electrical signals), resulting in smaller, faster and more power-efficient chips than is possible with conventional technologies.
The new technology, called CMOS Integrated Silicon Nanophotonics, is the result of a decade of development at IBM's global research laboratories. The patented technology will change and improve the way computer chips communicate -- by integrating optical devices and functions directly onto a silicon chip, enabling over 10X improvement in integration density than is feasible with current manufacturing techniques.

IBM anticipates that Silicon Nanophotonics will dramatically increase the speed and performance between chips, and further the company's ambitious exascale computing program, which is aimed at developing a supercomputer that can perform one million trillion calculations -- or an exaflop -- in a single second. An exascale supercomputer will be approximately one thousand times faster than the fastest machine today.

"The development of the Silicon Nanophotonics technology brings the vision of on-chip optical interconnections much closer to reality," said Dr. T.C. Chen, vice president, Science and Technology, IBM Research. "With optical communications embedded into the processor chips, the prospect of building power-efficient computer systems with performance at the exaflop level is one step closer to reality."

In addition to combining electrical and optical devices on a single chip, the new IBM technology can be produced on the front-end of a standard CMOS manufacturing line and requires no new or special tooling. With this approach, silicon transistors can share the same silicon layer with silicon nanophotonics devices. To make this approach possible, IBM researchers have developed a suite of integrated ultra-compact active and passive silicon nanophotonics devices that are all scaled down to the diffraction limit -- the smallest size that dielectric optics can afford.

"Our CMOS Integrated Nanophotonics breakthrough promises unprecedented increases in silicon chip function and performance via ubiquitous low-power optical communications between racks, modules, chips or even within a single chip itself," said Dr. Yurii A. Vlasov, Manager of the Silicon Nanophotonics Department at IBM Research. "The next step in this advancement is to establishing manufacturability of this process in a commercial foundry using IBM deeply scaled CMOS processes."

By adding just a few more processing modules to a standard CMOS fabrication flow, the technology enables a variety of silicon nanophotonics components, such as: modulators, germanium photodetectors and ultra-compact wavelength-division multiplexers to be integrated with high-performance analog and digital CMOS circuitry. As a result, single-chip optical communications transceivers can now be manufactured in a standard CMOS foundry, rather than assembled from multiple parts made with expensive compound semiconductor technology.

The density of optical and electrical integration demonstrated by IBM's new technology is unprecedented -- a single transceiver channel with all accompanying optical and electrical circuitry occupies only 0.5mm2 -- 10 times smaller than previously announced by others. The technology is amenable for building single-chip transceivers with area as small as 4x4mm2 that can receive and transmit over Terabits per second that is over a trillion bits per second.

The development of CMOS Integrated Silicon Nanophotonics is the culmination of a series of related advancements by IBM Research that resulted in the development of deeply scaled front-end integrated Nanophotonics components for optical communications. These milestones include:

* March 2010, IBM announced a Germanium Avalanche Photodetector working at unprecedented 40Gb/s with CMOS compatible voltages as low as 1.5V. This was the last piece of the puzzle that completes the prior development of the "nanophotonics toolbox" of devices necessary to build the on-chip interconnects.
* March 2008, IBM scientists announced the world's tiniest nanophotonic switch for "directing traffic" in on-chip optical communications, ensuring that optical messages can be efficiently routed.
* December 2007, IBM scientists announced the development of an ultra-compact silicon electro-optic modulator, which converts electrical signals into the light pulses, a prerequisite for enabling on-chip optical communications.
* December 2006, IBM scientists demonstrated silicon nanophotonic delay line that was used to buffer over a byte of information encoded in optical pulses -- a requirement for building optical buffers for on-chip optical communications.

The details and results of this research effort was reported in a presentation delivered by Dr. Yurii Vlasov at the major international semiconductor industry conference SEMICON held in Tokyo on Dec. 1, 2010. The talk is entitled "CMOS Integrated Silicon Nanophotonics: Enabling Technology for Exascale Computational Systems," co-authored by William Green, Solomon Assefa, Alexander Rylyakov, Clint Schow, Folkert Horst, and Yurii Vlasov of IBM's T.J. Watson Research Center in Yorktown Heights, N.Y. and IBM Zurich Research Lab in Rueschlikon, Switzerland.

Longevity Breakthrough: Scientists 'Activate' Life Extension in Worm, Discover Mitochondria's Metabolic State Controls Life Span


If you think life's too short, then you're not alone. A team of scientists set out to find what it would take to live a very long life and they made important discoveries that bring longer life spans much closer to reality. A new research report featured on the cover of The FASEB Journal, describes how scientists "activated" life extension in the roundworm C. elegans, and in the process discovered a new metabolic state correlating with long life.

The discovery was reported by lead author Jeffrey A. Butler and corresponding author Shane L. Rea, of the Barshop Institute for Longevity and Aging Studies and the Department of Physiology at the University of Texas Health Science Center at San Antonio, in collaboration with Natascia Ventura, of the Department of Experimental Medicine and Biochemical Sciences, University of Rome Tor Vergata, and Thomas E. Johnson, of the Department of Integrative Physiology, Institute for Behavioral Genetics, University of Colorado.

To make this discovery, scientists compared one class of long-lived C. elegans, called the Mit mutants (which have disrupted mitochondrial electron transport chain functionality), with non-mutant wild type C. elegans. Their comparison showed significant metabolism changes, suggesting that their cellular engines had been reconfigured to run on new fuels and to make new waste products, leading to increased lifespans.

To determine the cause of these metabolism changes, scientists created a new method for collecting cellular waste and studied it to identify the specific chemical reactions. They found that that the worms achieved long life through changes in how their cells extracted energy (metabolic state). Although C. elegans often is used as an animal model for human biology, more research is needed to determine if an equivalent metabolic state could be created in humans with the same results.

"C. elegans has provided a useful animal model for human biology," said Gerald Weissmann, M.D., Editor-in-Chief of The FASEB Journal, "because of their relative simplicity and our understanding of the genes that control their metabolism. Helping these worms to live longer is a proof of concept; indeed much of what we now know about human aging was first worked out in these worms."

"This research on worms shows that the secret to a long life comes from how we extract energy from our food," commented Weissmann. "With any luck, we'll be able to change human life in the same direction: onward and upward!"

Physicists Create Supernova in a Jar


A team of physicists from the University of Toronto and Rutgers University has mimicked a supernova -- an explosion of a star -- in miniature.
In a certain type of supernova, the detonation starts with a flame ball buried deep inside a white dwarf. The flame ball is much lighter than its surroundings, so it rises rapidly making a plume topped with an accelerating smoke ring.

"We created a smaller version of this process by triggering a special chemical reaction in a closed container that generates similar plumes and vortex rings," says Stephen Morris, a University of Toronto physics professor.

Autocatalytic chemical reactions release heat and change the composition of a solution, which can create buoyancy forces that can stir the liquid, leading to more reaction and a runaway explosive process. "A supernova is a dramatic example of this kind of self-sustaining explosion in which gravity and buoyancy forces are important effects. We wanted to see what the liquid motion would look like in such a self-stirred chemical reaction," says Michael Rogers, who led the experiment as part of his PhD research, under the supervision of Morris.

"It is extremely difficult to observe the inside of a real exploding star light years away so this experiment is an important window into the complex fluid motions that accompany such an event," Morris explains. "The study of such explosions in stars is crucial to understanding the size and evolution of the universe."

The research will appear in Physics Review E in the next few weeks. In addition to Morris and Rogers, the research team included Abdelfattah Zebib from Rutgers. The work was funded by the Natural Sciences and Engineering Research Council of Canada.

Distribution of Gravitational Wave Sources Predicted


A pair of neutron stars spiraling toward each other until they merge in a violent explosion should produce detectable gravitational waves. A new study led by an undergraduate at the University of California, Santa Cruz, predicts for the first time where such mergers are likely to occur in the local galactic neighborhood.

According to Enrico Ramirez-Ruiz, associate professor of astronomy and astrophysics at UC Santa Cruz, the results provide valuable information for researchers at gravitational-wave detectors, such as the Laser Interferometry Gravitational-Wave Observatory (LIGO) in Louisiana and Washington. "This is a very important result, as it is likely to significantly alter how gravitational-wave observatories currently operate," Ramirez-Ruiz said.

Luke Zoltan Kelley, a UCSC undergraduate working with Ramirez-Ruiz, is first author of a paper describing the new findings, to be published in the December 10 issue of Astrophysical Journal Letters and currently available online.

A key prediction of Einstein's general theory of relativity, gravitational waves are ripples in the fabric of space-time caused by the motions of massive objects. Scientists have yet to detect gravitational waves directly because they are so weak and decay rapidly, but a planned upgrade for LIGO (called Advanced LIGO) is expected to greatly increase its sensitivity. Compact binaries--which can consist of two neutron stars, two black holes, or one of each--are among the best candidates for emitting gravitational waves that could be detected by LIGO or other current experiments.

Kelley investigated the implications of a key observation about compact binaries: The two objects are not only moving in orbit around each other, they are also typically speeding through space together, their center of mass moving with a velocity that can be well above 200 kilometers per second.

"By the time the two objects merge, they are likely to be located far away from the galaxy where they were born," Kelley said.

This has implications for efforts to observe mergers that emit gravitational waves. Scientists hope to match a detection at a gravitational-wave observatory with telescope observations of the corresponding merger event. The new study suggests that astronomers might not want to look in the nearest galaxies for these "optical counterparts" of gravitational waves.

"Our predictions show that the proposed use of galaxy catalogs for follow-up from possible gravity-wave detections will need to account for the possibility of mergers away from the observed galaxies," Ramirez-Ruiz said.

The "kick" that sends compact binaries sailing out of their home galaxies comes from a slight asymmetry in the supernova explosions that give birth to neutron stars and black holes. When a massive star explodes, its core collapses to form either a neutron star (a rapidly rotating ball of densely packed neutrons) or a black hole. According to Kelley, a one-percent asymmetry in the supernova explosion would result in a recoil velocity of about 1,000 kilometers per second (about 2 million miles per hour).

"That is around the maximum velocity observed for lone neutron stars and pulsars," he said. "In binary systems, the net kick velocity to the center of mass is noticeably less, and still fairly uncertain, but is around 200 kilometers per second."

The researchers used a standard cosmological simulation of dark matter and the formation of structure in the universe to study how different kick velocities would affect the distribution of merging compact binaries. The simulation, run on a supercomputer at UCSC, showed the formation of halos of dark matter whose gravitational pull is thought to drive the formation of galaxies. The researchers populated the more massive halos with tracer particles representing compact binary systems. On separate runs, they gave the binaries different velocities.

After running the model for a simulated 13.8 billion years (the current age of the universe), Kelley found a region that looked like our local universe, with a galaxy the size of the Milky Way surrounded by a comparable set of neighboring galaxies. He then generated an image of the sky as it would appear to astronomers in the simulated universe, showing the locations of compact binaries and local galaxies.

The results showed that variations in kick velocity lead to marked differences in the distribution of compact binaries. If the merger of a compact binary occurs away from the bright background of a galaxy, it could be detected by a survey telescope such as the planned Large Synoptic Survey Telescope (LSST). The operators of gravitational-wave observatories would then know when and where to look in their data for a gravitational-wave signal, Ramirez-Ruiz said.

He and colleagues at UCSC, including theoretical astrophysicist Stan Woosley and graduate student Luke Roberts, are currently trying to work out what the optical signal of a compact-binary merger should look like. "Detecting the optical counterparts of gravitational-wave detections will be a lot easier if they are not within galaxies," Ramirez-Ruiz said.

Kelley is currently finishing up his senior thesis at UCSC, helping Ramirez-Ruiz teach an astrophysics class, and deciding where he will go to graduate school.

In addition to Kelley and Ramirez-Ruiz, the coauthors of the paper include Marcel Zemp of the University of Michigan, Ann Arbor; Jürg Diemand of the Institute for Theoretical Physics at the University of Zurich; and Ilya Mandel of the Kavli Institute at the Massachusetts Institute of Technology. This research was supported by NASA, the David and Lucile Packard Foundation, the U.S. National Science Foundation, and the Swiss National Science Foundation.

The Future of Metabolic Engineering: Designer Molecules, Cells and Microorganisms


Will we one day design and create molecules, cells and microorganisms that produce specific chemical products from simple, readily-available, inexpensive starting materials? Will the synthetic organic chemistry now used to produce pharmaceutical drugs, plastics and a host of other products eventually be surpassed by metabolic engineering as the mainstay of our chemical industries? Yes, according to Jay Keasling, chemical engineer and one of the world's foremost practitioners of metabolic engineering.
In a paper published in the journal Science Keasling discusses the potential of metabolic engineering -- one of the principal techniques of modern biotechnology -- for the microbial production of many of the chemicals that are currently derived from non-renewable resources or limited natural resources. Examples include, among a great many other possibilities, the replacement of gasoline and other transportation fuels with clean, green and renewable biofuels.

"Continued development of the tools of metabolic engineering will be necessary to expand the range of products that can be produced using biological systems, Keasling says. "However, when more of these tools are available, metabolic engineering should be just as powerful as synthetic organic chemistry, and together the two disciplines can greatly expand the number of chemical products available from renewable resources."

Keasling is the chief executive officer for the Joint BioEnergy Institute, a U.S. Department of Energy (DOE) bioenergy research center. He also holds joint appointments with the Lawrence Berkeley National Laboratory (Berkeley Lab), where he oversees that institute's biosciences research programs, and the University of California (UC), Berkeley, where he serves as director of the Synthetic Biology Engineering Research Center, and is the Hubbard Howe Jr. Distinguished Professor of Biochemical Engineering.

Metabolic engineering is the practice of altering genes and metabolic pathways within a cell or microorganism to increase its production of a specific substance. Keasling led one of the most successful efforts to date in the application of metabolic engineering, when he combined it with synthetic organic chemistry techniques to develop a microbial-based means of producing artemisinin, the most potent of all anti-malaria drugs. He and his research group at JBEI are now applying that same combination to the synthesis of liquid transportation fuels from lignocellulosic biomass. In all cases, the goal is to engineer microbes to perform as much of the chemistry required to produce a desired final product as possible.

"To date, microbial production of natural chemical products has been achieved by transferring product-specific enzymes or entire metabolic pathways from rare or genetically intractable organisms to those that can be readily engineered," Keasling says. "Production of non-natural specialty chemicals, bulk chemicals, and fuels has been enabled by combining enzymes or pathways from different hosts into a single microorganism, and by engineering enzymes to have new function."

These efforts have utilized well-known, industrial microorganisms, but future efforts, he says, may include designer molecules and cells that are tailor-made for the desired chemical and production process.

"In any future, metabolic engineering will soon rival and potentially eclipse synthetic organic chemistry," Keasling says.

Keasling cites the production of active pharmaceutical ingredients as one area where metabolic engineering enjoys a distinct advantage over synthetic organic chemistry. This includes three specific classes of chemicals -- alkaloids, which are primarily derived from plants; polyketides and non-ribosomal peptides, which are produced by various bacteria and fungi; and isoprenoids, which also are typically produced by microbes.

"Many of these natural products are too complex to be chemically synthesized and yet have a value that justifies the cost of developing a genetically engineered microorganism," Keasling says. "The cost of starting materials is generally a small fraction of the complete cost of these products, and relatively little starting material is necessary so availability is not an issue."

Keasling also says that metabolic engineering could provide a valuable alternative means of producing variations of terpenes, the hydrocarbon compounds common to the resins of conifers, in a form that could yield pharmaceuticals that are more effective for the treatment of human disease than the forms that nature has provided.

Perhaps the ripest targets of opportunity for future metabolic engineering efforts are petroleum-based bulk chemical products, including gasoline and other fuels, polymers and solvents. Because such products can be inexpensively catalyzed from petroleum, microbial production has until now been rare, but with fluctuating oil prices, dwindling resources and other considerations, the situation, Keasling says, has changed.

"It is now possible to consider production of these inexpensive bulk chemicals from low-cost starting materials, such as starch, sucrose, or cellulosic biomass with a microbial catalyst," he says. "The key to producing these bulk chemicals in metabolically-engineered cells will be our ability to make the exact molecule needed for existing products rather than something 'similar but green' that will require extensive product testing before it can be used."

In his Science paper, Keasling discusses the formidable roadblocks that stand in the way of a future in which microorganisms and molecules can be tailor-made through metabolic engineering, including the need for "debugging routines" that can find and fix errors in engineered cells. However, he is convinced these roadblocks can and will be overcome.

"One can even envision a day when cell manufacturing is done by different companies, each specializing in certain aspects of the synthesis, with one company constructing the chromosome, one company building the membrane and cell wall bag, and one company filling this bag with the basic molecules needed to boot up the cell."

The Joint BioEnergy Institute (JBEI) is one of three Bioenergy Research Centers funded by the U.S. Department of Energy to advance the development of the next generation of biofuels. It is a scientific partnership led by Berkeley Lab and including the Sandia National Laboratories, the University of California campuses of Berkeley and Davis, the Carnegie Institution for Science, and the Lawrence Livermore National Laboratory.

The Synthetic Biology Engineering Research Center (SynBERC) is a multi-institution partnership, funded by the National Science Foundation, that is aimed at "making biology easier to engineer." The SynBERC partnership is led by UC Berkeley and includes UC San Francisco, Harvard, MIT, Stanford, and Prairie View A&M University.

Dark Matter Could Transfer Energy in the Sun


Researchers from the Institute for Corpuscular Physics (IFIC) and other European groups have studied the effects of the presence of dark matter in the Sun. According to their calculations, low mass dark matter particles could be transferring energy from the core to the external parts of the Sun, which would affect the quantity of neutrinos that reach Earth.
"We assume that the dark matter particles interact weakly with the Sun's atoms, and what we have done is calculate at what level these interactions can occur, in order to better describe the structure and evolution of the Sun," Marco Taoso, researcher at the IFIC, a combined centre of the Spanish National Research Council and the University of Valencia, explains.

The astrophysical observations suggest that our galaxy is situated in a halo of dark matter particles. According to the models, some of these particles, the WIMPs (Weakly Interacting Massive Particles) interact weakly with other normal ones, such as atoms, and could be building up on the inside of stars. The study, recently published in the journal Physical Review D, carries out an in-depth study of the case of the Sun in particular.

"When the WIMPs pass through the Sun they can break up the atoms of our star and lose energy. This prevents them from escaping the gravitational force of the Sun which captures them, and they become trapped, orbiting inside it, with no way of escaping," the researcher points out.

The dark matter cools down the Sun's core

Scientists believe that the majority of the dark matter particles gather together in the centre of the Sun, but in their elliptic orbits they also travel to the outer part, interacting and exchanging with the solar atoms. In this way, the WIMPs transport the energy from the burning central core to the cooler peripheral parts.

"This effect produces a cooling down of the core, the region from where the neutrinos originate due to the nuclear reactions of the Sun," Taoso points out. "And this corresponds to a reduction in the flux of solar neutrinos, since these depend greatly on the temperature of the core."

The neutrinos that reach Earth can be measured by means of different techniques. These data can be used to detect the modifications of the solar temperature caused by the WIMPs. The transport of energy by these particles depends on the likelihood of them interacting with the atoms, and the "size" of these interactions is related to the reduction in the neutrino flux.

"As a result, current data about solar neutrinos can be used to put limits on the extent of the interactions between dark matter and atoms, and using numerical codes we have proved that certain values correspond to a reduction in the flux of solar neutrinos and clash with the measurements," the scientist reveals.

The team has applied their calculations to better understand the effects of low mass dark matter particles (between 4 and 10 gigaelectronvolts). At this level we find models that attempt to explain the results of experiments such as DAMA (beneath an Italian mountain) or CoGent (in a mine in the USA), which look for dark material using "scintillators" or WIMP detectors.

Debate about WIMP and solar composition

This year another study by scientists from Oxford University (United Kingdom) also appeared. It states that WIMPs not only reduce the fluxes of solar neutrinos, but also, furthermore, modify the structure of the Sun and can explain its composition.

"Our calculations, however, show that the modifications of the star's structure are too small to support this claim and that the WIMPs cannot explain the problem of the composition of the sun," Taoso concludes.