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Meet the other ancestors Magic material graphene set to overcome its last hurdle
Trends
THIS UNIVERSE |
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Meet the other ancestors
A distinct group of prehistoric people who lived in what is now south-west China more than 11,500 years ago could be a new human species, according to scientists who have completed a detailed analysis of their fossilised skeletons and skulls. Researchers said the unique anatomy of what they call the “red deer cave people” meant they were either a very ancient tribe of Homo sapiens that had become isolated for tens of thousands of years from the rest of humanity, or a completely new human species. A new species would add a further complication to the already complex story of human origins. It would mean there was a time when our own species, H. sapiens, shared the same non-African landscapes with at least four other human species until each in turn became extinct, allowing just one type of human to dominate the globe. The red deer people hunted and cooked an extinct ice-age species of giant deer that lived in the area of Yunnan province in southern China. The remains of at least four red deer people, and their skulls, were excavated from two cave sites, one near the city of Mengzi in Yunnan and the other near the village of Longlin in the neighbouring region of Guangzi Zhuang. Charred deer bones suggest that this extinct ice-age animal was a principal source of food, said Professor Darren Curnoe of the University of New South Wales in Australia, who carried out the study with Professor Ji Xueping of the Yunnan Institute of Cultural Relics and Archaeology, published in PLoS One, a journal produced by the Public Library of Science in the United States. “The unique anatomy of the skulls of the red deer cave people shows they represent a previously unknown prehistoric population. They could be a new evolutionary line or a previously unknown modern human population that arrived early from Africa and failed to contribute genetically to living East Asians,” Professor Curnoe said. “We have dated the remains to between about 14,500 and 11,500 years ago, which means that these people are the youngest population to be found anywhere in the world whose anatomy doesn’t comfortably fit within the range of modern humans,” he said. “While finely balanced, I think the evidence is slightly weighted towards the red deer cave people representing a new evolutionary line. They look very different to all modern humans, whether alive today or in Africa 150,000 years ago,” Professor Curnoe added. There were at least three other extinct human species living alongside H. sapiens in Europe and Asia, but until a decade ago only one of them was known to science—the Neanderthals, who inhabited a large territory extending from the Middle East to western Europe. Neanderthals lived from around 400,000 years ago until they became extinct about 30,000 years ago. More recently, scientists discovered two more distinct human species that had lived outside Africa at the same time as H. sapiens. The Denisovans, who occupied a cave site at Denisova in the Altai Mountains of Siberia, died out about 40,000 years ago, while the miniature “Hobbits” (Homo floresiensis) lived on the Indonesian island of Flores until about 18,000 years ago. The only other species of human found in Asia is the much older Homo erectus, which predated H. sapiens. While H. erectus emerged from Africa about 1.9 million years ago, H. sapiens migrated only about 70,000 years ago. Professor Curnoe said the red deer people showed little close similarity to any of these other human species. “They don’t show any particular resemblances to the Neanderthals. If anything, they show a mix of H. sapiens-like and H. erectus-like features, as well as some unusual traits,” he said. “Their skulls are an unusual mosaic of primitive features, like those seen in our ancestors hundreds of thousands of years ago, some modern traits, similar to living people, and several unusual features. In short, they’re anatomically unique among all members of the human evolutionary tree,” he said. “The main ways they differ from modern H. sapiens are in their prominent brow ridges, thick skull bones, flat upper faces with a broad nose, and jutting jaws that lack a human-like chin,” he added. Further studies will clarify the type of stone tools these people used to hunt and butcher their quarry, which they cooked over fires. “They clearly had a taste for venison, with evidence they cooked these large deer in the cave,” Professor Curnoe said. They must also have been tough enough to survive the harsh climate at the end of the last Ice Age. “They survived the final, and one of the worst, cold episodes: the Last Glacial Maximum, around 20,000 years ago,” he said. “This time also saw a major shift in the behaviour of modern humans in southern China, who began to make pottery for food storage and to gather wild rice. This marks some of the first steps towards full-blown farming.” — The Independent |
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Magic material graphene set to overcome its last hurdle PRESENTLY, graphene is the rock star of materials science, but it has a downside—it is extremely sensitive to its electrical environment. This single-atom-thick honeycomb of carbon atoms is lighter than aluminum, stronger than steel and conducts heat and electricity better than copper. As a result, scientists around the world are trying to turn it into better computer displays, solar panels, touchscreens, integrated circuits and biomedical sensors, among other possible applications. However, it has proven extremely difficult to reliably create graphene-based devices that live up to its electrical potential when operating at room temperature and pressure. Now, a team of Vanderbilt physicists reports that they have nailed down the source of the interference inhibiting the rapid flow of electrons through graphene-based devices and found a way to suppress it. This discovery allowed them to achieve record-levels of room-temperature electron mobility—the measure of the speed that electrons travel through a material—three times greater than those reported in previous graphene-based devices. According to the experts, graphene may have the highest electron mobility of any known material. In practice, however, the measured levels of mobility, while significantly higher than in other materials like silicon, have been considerably below its potential. “The problem is that, when you make graphene, you don’t get just graphene. You also get a lot of other stuff,” said Kirill Bolotin, assistant professor of physics, who conducted the study with research associate A.K.M. Newaz. “Graphene is extraordinarily susceptible to external influences so the electrical fields created by charged impurities on its surface scatter the electrons traveling through the graphene sheets, making graphene-based transistors operate slower and heat up more.” A number of researchers had proposed that the charged impurities that are omnipresent on the surface of graphene were the main culprits, but they were not completely certain. “Our study shows without question that the charged stuff is the problem and, if you want to make better graphene devices, it is the enemy that you need to fight,” Bolotin said. — ANI
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Trends
CAPE CANAVERAL, Florida: The first privately-owned passenger spaceship is on track for a test flight beyond the atmosphere this year, and nearly 500 people have signed up for rides. Another company just closed on $5 million equity financing, enough to finish building a two-seater rocketplane called Lynx. Both firms—and a half-dozen more -- are looking at flying not just people, but experiments and payloads owned by research laboratories, businesses and educational institutes.
Boeing wins contract for all-electric satellites WASHINGTON: Boeing Co. has announced a four-satellite contract for a new “small platform” version of its 702 satellite that will be powered solely by electric motors—a technology breakthrough that Boeing said would help reduce costs in the highly competitive satellite market. Boeing said it invested a “sizeable” amount over the past two years to develop the new 702SP satellites—a sign of the growing importance of commercial sales to the company and the dearth of new US government satellite development programmes. — Reuters
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Why does Jupiter have a stronger magnetic field as compared to Earth,even though it is a gas giant? Yes, it is a gas planet. The gas is mostly hydrogen, which is at extremely high temperature and high pressure. Under these conditions, the material is highly conducting. With its rotation, Jupiter is ideal for supporting electric activity in its convecting interior. That is the reason for its high magnetic field. Electromagnetic activity of Jupiter is phenomenal. It is sometimes said that Jupiter is actually a star that escaped being born. Even unborn Jupiter emits more energy than what it receives from the sun. It is mostly in radio frequencies. The dense superhot hydrogen core also rotates and the fact that Jupiter has a strong magnetic field is no surprise. We know that the mass of an object does not change with increasing velocity. But in case of atomic particles, which move with a velocity comparable to that of light, the mass increases when velocity tends to be that of light’s and the mass finally becomes infinite. How? I think there are some erroneous ideas here. The velocity cannot go on increasing at high energy but matter can be accelerated to values where the momentum does go on increasing. Rest mass does not increase. Velocity might increase very little till it reaches close to a maximum value, but the energy and momentum can go on increasing as the energy of the particle is increased. |
