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3000-year-old furnace rebuilt by archaeologist
A team led by a Cardiff University archaeologist has reconstructed a 3,000-year-old glass furnace, showing that Ancient Egyptian glassmaking methods were much more advanced than previously thought.Dr Paul Nicholson, of the University’s School of History and Archaeology, is leader of an Egypt Exploration Society team working on the earliest fully excavated glassmaking site in the world. The site, at Amarna, on the banks of the Nile, dates back to the reign of Akhanaten (1352 - 1336 B.C.), just a few years before the rule of Tutankhamun.It was previously thought that the Ancient Egyptians may have imported their glass from the Near East at around this time. However, the excavation team believes the evidence from Amarna shows they were making it themselves, possibly in a single stage operation. Dr Nicholson and his colleague Dr Caroline Jackson of Sheffield University demonstrated this was possible, using local sand to produce a glass ingot from their own experimental reconstruction of a furnace near the site.The team have also discovered that the glassworks was part of an industrial complex which involved a number of other high temperature manufacturing processes. The site also contained a potter’s workshop and facilities for making blue pigment and faience - a material used in amulets and architectural inlays. The site was near one of the main temples at Amarna and may have been used to produce materials in state buildings.Dr Nicholson, who has been working at Amarna since 1983, said: “It has been argued that the Egyptians imported their glass and worked it into the artefacts that have been discovered from this time. I believe there is now enough evidence to show that skilled craftsmen could make their own glass and were probably involved in a range of other manufacturing industries as well.”
Source: Cardiff University
Scientists have discovered what they think may be another reason why Greenland 's ice is melting: a thin spot in Earth's crust is enabling underground magma to heat the ice.
They have found at least one “hotspot” in the northeast corner of Greenland -- just below a site where an ice stream was recently discovered.
The researchers don't yet know how warm the hotspot is. But if it is warm enough to melt the ice above it even a little, it could be lubricating the base of the ice sheet and enabling the ice to slide more rapidly out to sea.
“The behavior of the great ice sheets is an important barometer of global climate change,” said Ralph von Frese, leader of the project and a professor of earth sciences at Ohio State University. “However, to effectively separate and quantify human impacts on climate change, we must understand the natural impacts, too.
“Crustal heat flow is still one of the unknowns -- and it's a fairly significant one, according to our preliminary results.”
Timothy Leftwich, von Frese's former student and now a postdoctoral engineer at the Center for Remote Sensing of Ice Sheets at the University of Kansas, presented the study's early results at the American Geophysical Union meeting in San Francisco.
von Frese's team combined gravity measurements of the area taken by a Naval Research Laboratory aircraft with airborne radar measurements taken by research partners at the University of Kansas. The combined map revealed changes in mass beneath the Earth's crust, and the topography of the crust where it meets the ice sheet.
Below the crust is the mantle, the partially molten rocky layer that surrounds the Earth's core. The crust varies in thickness, but is usually tens of miles thick. Even so, the mantle is so hot that temperatures just a few miles deep in the crust reach hundreds of degrees Fahrenheit, von Frese explained.
“Where the crust is thicker, things are cooler, and where it's thinner, things are warmer. And under a big place like Greenland or Antarctica , natural variations in the crust will make some parts of the ice sheet warmer than others,” he said.
The ice thickness, the temperature at the base of the ice, and ground topography all contribute to the forming of an ice stream -- a river of ice that flows within a larger ice sheet. In recent years, Greenland ice streams have been carrying ice out to sea faster, and ice cover on the island has been diminishing.
Once the ice reaches the sea, it melts, and global sea levels rise.
“The complete melting of these continental ice sheets would put much of Florida, as well as New Orleans, New York City and other important coastal population centers, under water,” von Frese said.
The ice sheet in northeast Greenland is especially worrisome to scientists. It had no known ice streams until 1991, when satellites spied one for the first time. Dubbed the Northeastern Greenland Ice Stream, it carries ice nearly 400 miles, from the deepest interior of the island out to the Greenland Sea.
“Ice streams have to have some reason for being there. And it's pretty surprising to suddenly see one in the middle of an ice sheet,” von Frese said.
The newly discovered hotspot is just below the ice stream, and could have caused it to form, the researchers concluded. But what caused the hotspot to form"
“It could be that there's a volcano down there,” he said. “But we think it's probably just the way the heat is being distributed by the rock topography at the base of the ice.”
Collaborator Kees van der Veen began working on the project when he was a visiting associate professor of geological sciences and research scientist at Byrd Polar Research Center at Ohio State. He is now at the University of Kansas.
“Recent observations indicate that the Greenland Ice Sheet is much more active than we ever believed,” van der Veen said. “There have been rapid changes in outlet glaciers, for example. Such behavior is critically linked to conditions at the ice bed. Geothermal heat is an important factor, but until now, our models have not included spatial variations in heat, such as this hotspot.
“Our map is the first attempt at quantifying spatial variations in geo-heat under Greenland -- and it explains why the Northeast Greenland Ice Stream is where it is,” van der Veen added.
To measure actual temperatures beneath the ice, scientists must drill boreholes down to the base of the ice sheet-- a mile or more below the ice surface. The effort and expense make such measurements few and far between, especially in remote areas of northeast Greenland.
For now, the researchers are combining theories of how heat flows through the mantle and crust with the gravity and radar data, to understand how the hotspot is influencing the ice.
Once they finish searching the rest of Greenland for other hotspots, they hope to turn their attention to Antarctica.Source: Ohio State University
Ireland Cancer Center of University Hospitals Case Medical Center researchers have recently made great strides in stem cell gene therapy research by transferring a new gene to cancer patients, via their own stem cells, with the ultimate goal of being able to use stronger chemotherapy treatment with less severe side effects. Under this protocol, MGMT, a drug-resistance gene, is added into purified hematopoietic stem cells to protect these cells from the damage of chemotherapy regimens.
In one of 24 presentations by Ireland Cancer Center researchers at the annual American Society of Hematology meeting, Stanton Gerson and colleagues presented that eight patients were enrolled on the trial and six were infused with their own stem cells which were engineered to carry the MGMT gene. In three patients, stem cells carrying the gene were identified in their blood or bone marrow. In one patient, stem cells carrying the gene were detected up to 28 weeks after their administration. This significant finding has never been reported before with this gene and drug combination.
This study is the first to show the success of treatment with evidence that stem cells now carry the new gene, says Dr. Gerson, Director of the Ireland Cancer Center and Case Comprehensive Cancer Center, who spearheaded the Phase I study along with a team of researchers. ¡§These patients show the success of treatment with evidence that their stem cells now carry the new genes. This is a breakthrough the first time selection with MGMT has been shown to occur in patients.
Preclinical animal research, conducted by Dr. Gerson and his colleagues, has shown that the gene G156A-MGMT can provide stem cells with very high levels of drug resistance, compared to normal stem cells not carrying the gene. In the Phase I trial for patients with advanced malignancies, researchers collected peripheral blood stem cells from patients and exposed them to a retrovirus containing the G156A-MGMT gene.
Source: University Hospitals of Cleveland
Findings suggest we are becoming more different, not alike
Countering a common theory that human evolution has slowed to a crawl or even stopped in modern humans, a new study examining data from an international genomics project describes the past 40,000 years as a time of supercharged evolutionary change, driven by exponential population growth and cultural shifts.
In a study published in the Proceedings of the National Academy of Sciences (PNAS), a team led by University of Wisconsin-Madison anthropologist John Hawks estimates that positive selection just in the past 5,000 years alone — around the period of the Stone Age — has occurred at a rate roughly 100 times higher than any other period of human evolution. Many of the new genetic adjustments are occurring around changes in the human diet brought on by the advent of agriculture, and resistance to epidemic diseases that became major killers after the growth of human civilizations.
“In evolutionary terms, cultures that grow slowly are at a disadvantage, but the massive growth of human populations has led to far more genetic mutations,” says Hawks. “And every mutation that is advantageous to people has a chance of being selected and driven toward fixation. What we are catching is an exceptional time.”
The findings may lead to a very broad rethinking of human evolution, Hawks says, especially in the view that modern culture has essentially relaxed the need for physical genetic changes in humans to improve survival. Adds Hawks: “We are more different genetically from people living 5,000 years ago than they were different from Neanderthals.”
While the correlation between population size and natural selection is nothing new — it was a core premise of Charles Darwin, Hawks says — the ability to bring quantifiable evidence to the table is a new and exciting outgrowth of the Human Genome Project.
Along with co-author Gregory Cochran, an anthropologist at the University of Utah; and Eric Wang of Affymetrix, Inc., in Santa Clara, Cal.; Hawks analyzed data from the International HapMap Project, short for haplotype mapping. This project is working to catalog genetic similarities and differences in human beings by studying genes from distinct sample populations around the globe. While the HapMap will ultimately be used to identify genes that affect human health, it can also provide a road map of genetic variation from the ancestral human population.
While more than 99 percent of the human genome is common across all humans, the HapMap project is cataloguing the individual differences in DNA called single nucleotide polymorphisms (SNPs). The project has mapped roughly 4 million of the estimated 10 million SNPs in the human genome. More importantly, it is identifying different regions of DNA, or haplotypes, that contain a large number of SNPs and are shared by multiple individuals.
In the hunt for recent genetic variation in this map, Hawks’ research focuses on a phenomenon called linkage disequilibrium (LD). These are places on the genome where genetic variations are occurring more often than can be accounted for by chance, usually because these changes are affording some kind of selection advantage.
The researchers identify recent genetic change by finding long blocks of DNA base pairs that are connected. Because human DNA is constantly being reshuffled through recombination, a long, uninterrupted segment of LD is usually evidence of positive selection. Linkage disequilibrium decays quickly as recombination occurs across many generations, so finding these uninterrupted segments is strong evidence of recent adaptation, Hawks says.
Employing this test, the researchers found evidence of recent selection on approximately 1,800 genes, or 7 percent of all human genes.
This finding runs counter to conventional wisdom in many ways, Hawks says. For example, there’s a strong record of skeletal changes that clearly show people became physically smaller, and their brains and teeth are also smaller. This is generally seen as a sign of relaxed selection – that size and strength are no longer key to survival.
But other pathways for evolution have opened, Hawks says, and genetic changes are now being driven by major changes in human culture. One good example is lactase, the gene that helps people digest milk. This gene normally declines and stops activity about the time one becomes a teenager, Hawks says. But northern Europeans developed a variation of the gene that allowed them to drink milk their whole lives — a relatively new adaptation that is directly tied to the advance of domestic farming and use of milk as an agricultural product.
The biggest new pathway for selection relates to disease resistance, Hawks says. As people starting living in much larger groups and settling in one place roughly 10,000 years ago, epidemic diseases such as malaria, smallpox and cholera began to dramatically shift mortality patterns in people. Malaria is one of the clearest examples, Hawks says, given that there are now more than two dozen identified genetic adaptations that relate to malaria resistance, including an entirely new blood type known as the Duffy blood type.
Another recently discovered gene, CCR5, originated about 4,000 years ago and now exists in about 10 percent of the European population. It was discovered recently because it makes people resistant to HIV/AIDS. But its original value might have come from obstructing the pathway for smallpox.
“There are many things under selection that are making it harder for pathogens to kill us,” Hawks says.
Population growth is making all of this change occur much faster, Hawks says, giving a nod to Charles Darwin. When Darwin wrote in “Origin of the Species” about challenges in animal breeding, he always emphasized that herd size “is of the highest importance for success” because large populations have more genetic variation, Hawks says.
The parallel to humans is obvious: The human population has grown from a few million people 10,000 years ago to about 200 million people at 0 AD, to 600 million people in the year 1700, to more than 6.5 billion today. Prior to these times, the population was so small for so long that positive selection occurred at a glacial pace, Hawks says.
“What’s really amazing about humans, that is not true with most other species, is that for a long time we were just a little ape species in one corner of Africa, and weren’t genetically sampling anything like the potential we have now,” he says.
The recent changes are especially striking, he says. “Five thousand years is such a small sliver of time – it’s 100 to 200 generations ago,” he says. “That’s how long it’s been since some of these genes originated, and today they are in 30 or 40 percent of people because they’ve had such an advantage. It’s like ‘invasion of the body snatchers.’”
Source: Proceedings of the National Academy of Sciences
A team of astronomers have used the NASA/ESA Hubble Space Telescope to detect, for the first time, strong evidence of hazes in the atmosphere of a planet orbiting a distant star. The discovery comes after extensive observations made recently with Hubble’s Advanced Camera for Surveys (ACS).
The team, led by Frédéric Pont from the Geneva University Observatory in Switzerland, used Hubble’s ACS to make the first detection of hazes in the atmosphere of the giant planet. "One of the long-term goals of studying extrasolar planets is to measure the atmosphere of an Earth-like planet, this present result is a step in this direction" says Pont. "HD 189733b is the first extrasolar planet for which we are piecing together a complete idea of what it really looks like."
The new observations were made as the extrasolar planet, dubbed HD 189733b, passed in front of its parent star in a transit. As the light from the star passes through the atmosphere around the limb of the giant extrasolar planet, the gases in the atmosphere stamp their unique signature on the starlight from HD 189733.
The planet itself, orbiting close to its parent star, is a ‘hot-Jupiter’ type of gas giant slightly larger than Jupiter. The proximity to its star results in an atmospheric temperature of roughly seven hundred degrees Celsius. Measurements of the way light varies as the planet passes in front of its parent star indicates that HD 189733b has neither Earth-sized moons nor any discernable Saturn-like ring system.
Hubble’s ACS camera, coupled with a grism (a kind of cross between a prism and a diffraction grating) allowed the astronomers to make extremely accurate measurements of the spectrum of HD 189733b, allowing conclusions to be drawn about the composition of the planet’s atmosphere. The exquisite level of precision needed to make this observation can only, at the moment, be achieved from space. The combination of a large planet and relatively small parent star – only 76% of the diameter of our Sun – contributes to the success of this delicate experiment.
Where the scientists had expected to see the fingerprints of sodium, potassium and water there were none. This finding, combined with the distinct shape of the planet’s spectrum, infers that high level hazes (with an altitude range of roughly 1000 km) are present. So the atmosphere on HD 189733b would look very similar to a gorgeous red sunset over Athens! Venus and Saturn’s moon Titan, in our own Solar System, are also covered with haze. According to the scientists the haze probably consists of tiny particles (less than 1/1000 mm in size) of condensates of iron, silicates and aluminium oxide dust (the compound on Earth which the mineral sapphire is made of).
As part of the observations of HD 189733, the teams of astronomers also needed to accurately account for the variations in the star’s brightness during the set of observations. ‘Starspots’ like those seen on our own Sun may cover several percent of the star and are thought to be about 1000 degrees Celsius cooler than the rest of HD 189733’s surface. It was found that there is a starspot on the star’s surface which is over 80,000 km across.
Source: ESA/Hubble Information Centre
Only second Jurassic dinosaur ever found in Antarctica
A new genus and species of dinosaur from the Early Jurassic has been discovered in Antarctica. The massive plant-eating primitive sauropodomorph is called Glacialisaurus hammeri and lived about 190 million years ago.
The recently published description of the new dinosaur is based on partial foot, leg and ankle bones found on Mt. Kirkpatrick near the Beardmore Glacier in Antarctica at an elevation of more than 13,000 feet.
“The fossils were painstakingly removed from the ice and rock using jackhammers, rock saws and chisels under extremely difficult conditions over the course of two field seasons,” said Nathan Smith, a graduate student at The Field Museum. “They are important because they help to establish that primitive sauropodomorph dinosaurs were more broadly distributed than previously thought, and that they coexisted with their cousins, the true sauropods.”
The findings were published in the Acta Palaeontologica Poloncica (see http://www.app.pan.pl/). Diego Pol, a paleontologist at the Museo Paleontológico Egidio Feruglio in Chubut, Argentina, is the other co-author of the research.
Sauropodomorph dinosaurs were the largest animals to ever walk the earth. They were long-necked herbivores and include Diplodocus and Apatosaurus. Their sister group is the theropods, which include Tyrannosaurus, Velociraptor, and modern birds.
Glacialisaurus hammeri was about 20-25 feet long and weighed about 4-6 tons . It was named after Dr. William Hammer, a professor at Augustana College who led the two field trips to Antarctica that uncovered the fossils. Glacialisaurus belongs to the sauropodomorph family Massopsondylidae, which may represent a secondary radiation of basal sauropodomorphs during the Early Jurassic.
Currently, the development and evolutionary relationships of the sauropodomorph dinosaurs are hotly debated by paleontologists. This discovery, however, helps to resolve some of this debate by establishing two things. First, it shows that sauropodomorphs were widely distributed in the Early Jurassic—not only in China, South Africa, South America and North America, but also in Antarctica.
“This was probably due to the fact that major connections between the continents still existed at that time, and because climates were more equitable across latitudes than they are today,” Smith said.
Second, the discovery of Glacialisaurus hammeri shows that primitive sauropodomorphs probably coexisted with true sauropods for an extended period of time. The recent discovery of a possible sauropod at roughly the same location in Antarctica lends additional evidence to the theory that the earliest sauropods coexisted with their basal sauropodomorph cousins, including Glacialisaurus hammeri, during the Late Triassic and Early Jurassic, Smith and Pol conclude in their research findings.
Source: Acta Palaeontologica Poloncica
The capacity of the human mind to believe or disbelieve a statement is a powerful force for controlling both behavior and emotion, but the basis of these states in the brain is not yet understood. A new study found that belief, disbelief and uncertainty activate distinct regions of the brain, with belief/disbelief affecting areas associated with the pleasantness/unpleasantness of tastes and odors. The study published in the Annals of Neurology (http://www.interscience.wiley.com/journal/ana), the official journal of the American Neurological Association.
Led by Sam Harris of the University of California, Los Angeles, the study involved 14 adults who underwent functional MRI scans during which they were presented with short statements that they had to evaluate as true, false or undecided. Each participant underwent three scans while they evaluated statements from a broad variety of categories such as mathematical, geographical, autobiographical, religious and factual. The statements were designed to be clearly true, false or undecidable.
Contrasting belief and disbelief trials yielded increased signal in the ventromedial prefrontal cortex (VMPFC), which is involved in linking factual knowledge with emotion. “The involvement of the VMPFC in belief processing suggests an anatomical link between the purely cognitive aspects of belief and human emotion and reward,” the authors state. The fact that ethical belief showed a similar pattern of activation to mathematical belief suggests that the physiological difference between belief and disbelief is not related to content or emotional associations, they note.
The contrasts between disbelief and belief showed increased signal in the anterior insula, a region involved in the sensation of taste, the perception of pain, and the feeling of disgust, indicating that “false propositions might actually disgust us,” the authors state. “Our results appear to make sense of the emotional tone of disbelief, placing it on a continuum with other modes of stimulus appraisal and rejection,” they add.
Uncertainty evoked a positive signal in the anterior cingulate cortext (ACC) and a decreased signal in the caudate, a region of the basal ganglia, which plays a role in motor action. Noting that both belief and disbelief showed an increased signal in the caudate compared to uncertainty, the authors suggest that the basal ganglia may play a role in mediating the cognitive and behavioral differences between decision and indecision.
The study raises the possibility that the differences between belief, disbelief and uncertainty may one day be reliably distinguished by neuroimaging techniques. They conclude: “This would have obvious implications for the detection of deception, for the control of the placebo effect during the process of drug design, and for the study of any higher-cognitive phenomenon in which the differences between belief, disbelief, and uncertainty might be a relevant variable.”Source: Annals of Neurology
A team led by a Cardiff University archaeologist has reconstructed a 3,000-year-old glass furnace, showing that Ancient Egyptian glassmaking methods were much more advanced than previously thought.
