The research aims to produce valid information and must use reliable instruments that guarantee accurate and make it quantifiable and possible reproducibility. Allowing the exclusion or at least control prejudice of personal insights and trends that may distort the results.
viernes, 27 de febrero de 2009
Using Astrobotics to Prepare a Lunar Outpost
According to a CMU news release, the CMU Robotics Institute has partnered with Astrobotic Technology, Inc. to prepare a NASA-sponsored study describing a lunar outpost constructed by robots. Small moon robots, described as the size of riding lawnmowers, would be used for tasks such as building a hard-surface landing pading and a surrounding semi-circular berm. Both structures would be constructed of indigenous materials (aka moon dirt).
NASA expects the lunar outpost to be in operation by 2020. Meanwhile William "Red" Whittaker, CMU professor and Astrobotic's chief technical officer is running field trials on the companies first lunar robot. For more details, see Astrobotics report, Configuring Innovative Regolith Moving Techniques for Lunar Outposts (PDF format). More renderings of the robots and moonbase after the break.
Things You Didn't Know About... Robots
1. “Robot” comes from the Czech word robota, meaning “drudgery,” and first appeared in the 1921 play R.U.R. (Rossum’s Universal Robots). The drama ends badly when the machines rise up and kill their creators, leaving a sole lonely survivor.
2. They say it was an accident. The first known case of robot homicide occurred in 1981, when a robotic arm crushed a Japanese Kawasaki factory worker.
3.More than a million industrial robots are now in use, nearly half of them in Japan.
4.Archytas of Tarentum, a pal of Plato’s, built a mechanical bird driven by a jet of steam or compressed air—arguably history’s first robot—in the fifth century B.C.
Publicado por Nathaniel en 6:41 No hay comentarios:
Clovis-era Tool Cache 13,000 Years Old Shows Evidence Of Camel, Horse Butchering
Douglas Bamforth, Anthropology professor for the University of Colorado at Boulder places his hand one of more than 80 artfiacts unearthed about two feet below Boulder resident Patrick Mahaffy's front yard during a landscaping project this past summer. The artifacts, which may have been made during the Clovis period nearly 13,000 years ago, were neatly arranged in a cache near where this portrait was taken, suggesting that the users of these instruments may have intended to reuse them. (Credit: Photo by Glenn J. Asakawa/University of Colorado)
ScienceDaily (Feb. 26, 2009) — More than 80 stone implements were discovered together in Boulder city limits by landscapers. A biochemical analysis of a rare Clovis-era stone tool cache recently unearthed in the city limits of Boulder, Colo., indicates some of the implements were used to butcher ice-age camels and horses that roamed North America until their extinction about 13,000 years ago, according to a University of Colorado at Boulder study.
The study is the first to identify protein residue from extinct camels on North American stone tools and only the second to identify horse protein residue on a Clovis-age tool, said CU-Boulder Anthropology Professor Douglas Bamforth, who led the study. The cache is one of only a handful of Clovis-age artifact caches that have been unearthed in North America, said Bamforth, who studies Paleoindian culture and tools.
The Clovis culture is believed by many archaeologists to coincide with the time the first Americans arrived on the continent from Asia via the Bering Land Bridge about 13,000 to 13,500 years ago, Bamforth said.
Named the Mahaffy Cache after Boulder resident and landowner Patrick Mahaffy, the collection is one of only two Clovis caches -- the other is from Washington state -- that have been analyzed for protein residue from ice-age mammals, said Bamforth. In addition to the camel and horse residue on the artifacts, a third item from the Mahaffy Cache is the first Clovis tool ever to test positive for sheep, and a fourth tested positive for bear.
Dozens of species of North American mammals went extinct by the end of the Pleistocene, including American camels, American horses, woolly mammoth, dire wolves, short-faced bears, saber-toothed cats, woolly rhinos and giant ground sloths. While some scientists speculate ice-age mammals disappeared as a result of overhunting, climate change or even the explosion of a wayward asteroid, the reasons are still unresolved, Bamforth said.
The Mahaffy Cache consists of 83 stone implements ranging from salad plate-sized, elegantly crafted bifacial knives and a unique tool resembling a double-bitted axe to small blades and flint scraps. Discovered in May 2008 by Brant Turney -- head of a landscaping crew working on the Mahaffy property -- the cache was unearthed with a shovel under about 18 inches of soil and was packed tightly into a hole about the size of a large shoebox. It appeared to have been untouched for thousands of years, Bamforth said.
Although the surface of the house lot had been lowered by construction work over the years, an analysis of photos from the Mahaffy Cache excavation site by CU-Boulder geological sciences Emeritus Professor Peter Birkeland confirmed the approximate age of sediment layer containing the Clovis implements. The site appears to be on the edge of an ancient drainage that ran northeast from Boulder's foothills, said Bamforth.
"The idea that these Clovis-age tools essentially fell out of someone's yard in Boulder is astonishing," he said. "But the evidence I've seen gives me no reason to believe the cache has been disturbed since the items were placed there for storage about 13,000 years ago."
All 83 artifacts were shipped to the anthropology Professor Robert Yohe of the Laboratory of Archaeological Science at California State, Bakersfield for protein residue tests that were funded by Mahaffy. The protein residue on the artifacts was tested against various animal anti-sera, a procedure similar to standard allergy tests and which can narrow positive reactions down to specific mammalian families, but not to genera or species.
"I was somewhat surprised to find mammal protein residues on these tools, in part because we initially suspected that the Mahaffy Cache might be ritualistic rather than a utilitarian," said Yohe. "There are so few Clovis-age tool caches that have been discovered that we really don't know very much about them.'
While the quality and patterns on several of the artifacts resemble Clovis stonework, "It was the camel and horse protein results that were the clincher for me," said Bamforth. "We haven't had camels or horses around here since the late Pleistocene." The artifacts that showed animal protein residues were each tested three times to ensure accuracy.
The artifacts were buried in a coarse, sandy sediment overlain by dark, clay-like soil and appear to have been cached on the edge of an ancient stream, said Bamforth. "It looks like someone gathered together some of their most spectacular tools and other ordinary scraps of potentially useful material and stuck them all into a small hole in the ground, fully expecting to come back at a later date and retrieve them."
Bamforth said he knew immediately that much of the stone used to craft the tools in the cache originated from Colorado's Western Slope and perhaps as far north as southern Wyoming. The stone appears to have come from at least four distinct regions, including sites in Colorado's Middle Park south of Steamboat Springs, he said.
Bamforth believes the type of people who buried the Mahaffy Cache "lived in small groups and forged relationships over large areas." "I'm skeptical that they wandered widely, and they may have been bound together by a larger human network." A single individual could have easily carried all of the Mahaffy Cache tools a significant distance, he said.
One of the tools, a stunning, oval-shaped bifacial knife that had been sharpened all the way around, is almost exactly the same shape, size and width of an obsidian knife found in a Clovis cache known as the Fenn Cache from south of Yellowstone National Park, said Bamforth. "Except for the raw material, they are almost identical," he said. "I wouldn't stake my reputation on it, but I could almost imagine the same person making both tools."
Climatic evidence indicates the Boulder area was cooler and wetter in the late Pleistocene and receding glaciers would have been prominent along the Front Range of Colorado, he said. "The kind of animals that were wandering around present-day Boulder at the end of the last ice age -- elephants, camels, huge bears and ground sloths -- are creatures we would expect to see in a zoo today."
A 2008 study led by the University of Oregon offers evidence that a cadre of comets exploded over North America about 12,900 years ago, triggering massive fires that caused the extinction of ice-age mammals and perhaps even the Clovis people. The evidence is based on a thin layer of microscopic diamonds found in ancient soil layers that could only have been created by searing heat and pressure transforming carbon on Earth's surface.
Mahaffy, who initially thought the stone tools were just a few hundred years old, called the CU-Boulder anthropology department the day of the discovery, and Bamforth came to the examine the cache the following day. "I think it's safe to say Doug got pretty excited based on his background and knowledge of the area," said Mahaffy, a Boulder biotechnology entrepreneur. The high-tech tests that confirmed the antiquity of the tools "are a nice marriage between modern biotechnology and anthropology," Mahaffy said.
"There is a magic to these artifacts," said Mahaffy. "One of the things you don't get from just looking at them is how incredible they feel in your hand --they are almost ergonomically perfect and you can feel how they were used. It is a wonderful connection to the people who shared this same land a long, long time ago." Mahaffy said the artifacts will likely wind up in a museum except for a few of the smaller pieces, which will be reburied at the cache site.
Publicado por Nathaniel en 6:35 No hay comentarios:
'Talking' Cars Could Hit the Road by 2012
Dust off that leather jacket and those tight jeans, Knight Rider fans. An Australian startup says "talking" cars could be on the road as soon as 2012 and the technology could reduce fatalities by half.
The technology developed by Cohda Wireless and researchers at the University of South Australia combines Wi-Fi and GPS technology in a system called dedicated short-range communications to make each car a node on a huge communication network. Those vehicles can communicate with each other and warn drivers of potential collisions. The company also claims the system would minimize traffic jams and curb emissions by more effectively managing traffic to avoid congestion.
"This technology essentially equips vehicles with the ability to see around corners and to predict and avoid dangerous situations," said professor Alex Grant, head of the university's Institute for Telecommunications.
Cohda is one of several companies joining automakers in developing car-to-car communications and in-car connectivity. Here in the United States, the goal is to create an Intelligent Transportation System where cars talk to each other and to us in a network designed to increase safety, reduce congestion and manage traffic. The Department of Transportation has been pushing the idea for years, but progress has been slower than rush hour traffic out of San Francisco.
But Cohda says the technology could be road-ready by 2012. It already has conducted 700 field trials in Australia, the United States and Italy, and it recently demonstrated the system for automakers and government officials Down Under. A $1.5 million field trial involving 200 cars is slated within two years. Now, if they can get cars to utter KITTisms like "Scanner indicates danger ahead" or "Engaging the infrared tracking scope" ...
Dedicated short-range communications uses Wi-Fi and GPS to share data with a centralized location and other vehicles via external Wi-Fi spots, effectively making each car a node on the network. The system was designed to work in urban environments — where radio signals can easily be lost among buildings, tunnels and the like — and does not require line-of-sight transmission to work.
"From a safety point of view, the conventional technology expected to be used for DSRC has problems when there is non-line-of-site, whereas our technology is able to see around the corner or see through buildings, Grant said.
The information could be used to track vehicle location — handy for fleet management — while also allowing vehicles to communicate with each other. Grant says that would allow vehicles to track their locations relative to each other 10 times every second, reducing the chance of collisions.
"On-board processing units assess the risk of an accident and provide advice to the driver," he said. "This technology essentially equips vehicles with the ability to see around corners and to predict and avoid dangerous situations."
And that, he said, could bring a significant decrease in traffic fatalities.
"Approximately 1,500 people die on Australian roads every year — and we're estimating that potentially half of those crashes could be avoided with the widespread use of this technology," he said.
Publicado por Nathaniel en 6:23 No hay comentarios:
Walk Like Us: 1.5 Million-Year-Old Footprints Look Modern
The second-oldest human footprints ever found show that mankind's ancestors walked out of Africa on feet indistinguishable from our own.
The 1.5 million-year-old footprints, found in sediment deposits in northern Kenya, are the oldest identified since Mary Leakey found 3.75 million-year-old tracks preserved in volcanic ash in northern Tanzania. Those prints belonged to Australopithecus afarensis, and provided clear evidence of bipedalism.
Though the short-legged, long-trunked A. Afarensis was able to walk upright, its feet were still apelike, possessing a telltale splayed-out big toe. Because the early fossil record contains no foot bones, scientists didn't know when modern feet — a defining human characteristic necessary for long-distance running — evolved.
The new footprints, described Thursday in Science, apparently belong to Homo erectus. Maker of the first stone tools, H. erectus was also the first hominid to leave Africa, migrating to Asia about two million years ago.
By scanning the footprints with lasers and measuring sediment compression, then comparing the results to A. afarensis and Homo sapiens, researchers determined that H. erectus had a modern foot and stride: a mid-foot arch, straight big toe and heel-to-toe weight transfer.
FootcomparisonsIn a commentary accompanying the study, primatologists Robin Huw Crompton and Todd Pataky say the footprints are "broadly indistinguishable from those of modern humans" and "herald an exciting time for the evolution of human gait."
Citations: "Early Hominin Foot Morphology Based on 1.5-Million-Year-Old Footprints from Ileret, Kenya." By Matthew R. Bennett, John W.K. Harris, Brian G. Richmond, David R. Braun, Emma Mbua, Purity Kiura, Daniel Olago, Mzalendo Kibunjia, Christine Omuombo, Anna K. Behrensmeyer, David Huddart, Silvia Gonzalez. Science, Vol. 323 Iss. 5918, Feb. 26, 2009.
Publicado por Nathaniel en 6:21 No hay comentarios:
JAGUAR PICTURE: First Caught in U.S.
For the first time in more than a century, a jaguar was caught and collared in the U.S.
The big cats have been photographed near the Arizona-Mexico border for years, but the newly captured specimen was found outside of its usual range, southwest of Tucson.
The Arizona Game and Fish Department spotted the 118-pound (54-kilogram) male during a research study of mountain lion and black bear habitat. It was later confirmed to be Macho B, an animal that has been photographed since 1996 and could be between 14 to 16 years old—making it the oldest jaguar ever collared.
The animal was released wearing a satellite-tracking collar, which will give biologists new insight into the little-studied population of northern jaguars.
"It's good news for jaguar conservation, and it's exciting that the U.S. is getting data on this small population," Jon Beckmann, a conservation ecologist for the Wildlife Conservation Society, told National Geographic News.
The sighting also stresses the importance of keeping habitat between the U.S. and Mexico unhindered, so that the big cats can roam freely, Beckmann added.
Jaguars, once common throughout the southern United States, were mostly killed off in the country by the early 1900s.
But observations of the cats around the Arizona border placed them under the protection of the U.S. Endangered Species Act in 1997.
Publicado por Nathaniel en 6:17 No hay comentarios:
A record-breaking stingray capture, by the numbers:
1 rod and line
90 minutes for one British biologist (with help) to reel in the freshwater fish
13 men to drag said fish onto a boat
125 pounds—that's the difference between the stingray's weight at 771 pounds and the previous record rod-&-reel capture of a catfish
The Thailand capture of the massive female stingray was part of a program to tag such Maeklong River residents. The captive, part of a "vulnerable species" listed by the International Union for Conservation of Nature, measured a hefty 7 feet by 7 feet. That doesn't include the 10-foot-long poisonous tail.
Such creatures are dangerous, of course: Famed Australian TV personality Steve "Crocodile Hunter" Irwin died from a stingray barb at the Great Barrier Reef in 2006. The numbers currently put one Ian Welch on the world record books. (Pictures of Welch posing with his female companion can be found here.) The stingray's resistance nearly dunked Welch into the river, and he was literally saved by the seat of his pants when a crewmate grabbed his trousers.
Another reason that this marine fish is so huge: She's pregnant. (Cue soap-opera gasp.) After she had been towed to the bank (too big to be onboard the boat), she was duly marked, had DNA samples removed, and returned to the river whence she unwillingly came. Welch gave her a farewell smooch, then spent the rest of the day with a cold beer and memories of her.
By the way, one number isn't known: the exact stingray population count, which has shrunk 20 percent in the past decade. With this lady's help, at least one more will be added to this number...and with a tale to tell.
Publicado por Nathaniel en 6:16 No hay comentarios:
Largest Freshwater Fish?
ishers and scientists announced this week the catch, and release, of what is likely the world's largest known freshwater giant stingray.
The giant stingray, weighing an estimated 550 to 990 pounds (250 to 450 kilograms) was reeled in on January 28, 2009, as part of a National Geographic expedition in Thailand.
The stringray's body measured 6.6 feet (2 meters) wide by 6.9 feet (2.1) meters long. The tail was missing. If it had been there, the ray's total length would have been between 14.8 and 16.4 feet (4.5 and 5 meters), estimated University of Nevada Biologist Zeb Hogan.
Hogan was in Thailand searching for giant fish as part of the Megafishes Project—an effort to document Earth's 20 or so freshwater giants.
The new find gives Hogan hope that the giant stingray, once overfished, may be more abundant than previously thought. And it may confirm the giant stingray as the heavyweight champ of the Megafishes Project.
"Honestly, we just don't know how much it weighed. But it's clear that the giant stingray has the potential to be the largest freshwater fish in the world," said Hogan, also a National Geographic Emerging Explorer. (National Geographic News is owned by the National Geographic Society.)
"The Thai populations were once considered critically endangered, although with the discovery of new populations the stingray's abundance appears higher than previously believed," added Hogan. The International Union for Conservation of Nature (IUCN) currently lists the freshwater giant stingray as vulnerable.
Last March Hogan found a 14-foot-long (4.3-meter-long) ray near the Thai city of Chachoengsao.
Freshwater giant stingrays are among the largest of the approximately 200 species of rays. They can be found in a handful of rivers in Southeast Asia and northern Australia.
Much is still unknown about the mammoth ray species, including whether or not it can swim out to and survive at sea. The species was first described scientifically only in 1989.
Hogan and his colleagues are still looking for new varieties and populations of the giant stingray.
Publicado por Nathaniel en 6:14 No hay comentarios:
New Stegosaur With Odd Long Neck Discovered
Stegosaurs have long been identified by the bony plates on their backs, the spikes on their tales, short forelimbs, and stubby little necks.
Now paleontologists have discovered a 150-million-year-old stegosaur (above) in Portugal with a neck that stretched over 5.9 feet (1.8 meters), a February 2009 study reported.
This stegosaur wasn't neck and neck with its peers.
The dinosaurs have long been identified by the bony plates on their backs, the spikes on their tales, short forelimbs, and stubby little necks.
But now paleontologists have discovered a 150-million-year-old stegosaur in Portugal with a neck that stretched over 5.9 feet (1.8 meters). (Read more about the Jurassic period.)
The neck of the new species, dubbed Miragaia longicollum, is considerably longer than the few inches seen on the average stegosaur neck. Miragaia's neck is also very long compared to the dinosaur's 19.6-foot (6-meter) body length.
The newly discovered stegosaur has 17 cervical vertebra, or neck bones—five more than a normal stegosaur and ten more than the modern giraffe. (See pictures of stegosaurs walking.)
"The increase in neck length among stegosaurs demonstrates the evolutionary [flexibility] of dinosaurs and their ability to adapt to change," said lead author Octavio Mateus at Universidade Nova de Lisboa in Portugal.
Having a long neck does not mean that Miragaia was all that different from other stegosaurs—just that it was probably grazing on taller foods, Mateus said.
One of the dinosaur's dietary staples, for example, was a group of fernlike plants called cycads.
"Cycads took on a variety of growth habits, including small treelike forms," noted paleontologist Paul Barrett at the Natural History Museum, London, who was not involved in the study.
"It's possible this animal was still feeding on cycads ... even if it was, on average, browsing at higher levels than other stegosaurs," Berrett said.
Publicado por Nathaniel en 6:03 No hay comentarios:
jueves, 26 de febrero de 2009
Ship Excavation Sheds Light On Napoleon's Attack On The Holy Land
Cannon ball wedged into the ship's keel. (Credit: Steve Breitstein)
Which navy commissioned the boat that sunk off the coast of Acre 200 years ago, which battles was it involved in and how did it end up at the bottom of the sea? The recent findings of marine archaeologists at the Leon Recanati Institute for Maritime Studies of the University of Haifa may provide the answers to these questions.
The ship, which sunk off the coast of Acre during a battle between Napoleon, the British navy and possibly the defenders of Acre, 200 years ago, is under excavation and its finds are beginning to shed light on Napoleon's attempt to conquer the Holy Land.
Recent marine excavations found cannon balls, canisters of gun powder and other items that will help give evidence as to the ship's journey and answer the questions facing marine archaeologists. It is not clear if the boat was involved in battles in 1799 or 1840, if it was a French or British boat or even if the boat sunk or was sunk. "This is the only shipwreck excavated from the period of the French blockade of Acre and it can teach us a lot about the naval battles of that period," explained Dr. Ya'acov Kahanov from the Leon Recanati Institute for Maritime Studies and the Department Of Maritime Civilizations at the University of Haifa.
This large ship, 30 meters long and 9 meters wide, was discovered off the Acre coast in 1966, but systematic excavations have only just begun under the auspices of the Leon Recanati Institute for Maritime Studies of the University of Haifa in cooperation with the Nautical Archaeology Society of Great Britain and with the help of the Nautical College for Naval Officers in Acre. The fact that cannon balls, gun powder canisters, wineskins and metal buckles were found, attest to the fact that this ship was part of a naval fleet. The question of which battle it was involved in has yet to be answered, but the archaeologists do have some theories.
It seems that the story of this boat begins over 200 years ago. Researchers found a map in a British archive, drawn in 1799 by a British soldier, of the British formation off the coast of Acre, facing a blockade of Napoleon's ships. The map includes a symbol of a sunken ship, at exactly the spot where this ship was found. This map is the source of the theory that this ship was involved in the battles of 1799. In addition, one of the cannon balls was found wedged into the keel of the boat, exactly at the bottom. The location and the unique angle at which the cannon ball is positioned, has led researchers to believe that it was this cannon ball that sank the ship.
"One of the theories is that this is a "barricade ship" - a ship that the British purposely sunk at the entrance of the port in order to block smaller French ships from entering it. The leather buckles, gun power canisters and the rest of the finds need to be analyzed to verify how the ship ended up at the bottom of the sea. Once we understand these questions, we will be able to understand more about battle tactics of that period, "said Dr. Kahanov.
Publicado por Nathaniel en 8:15 No hay comentarios:
Remains Of Ancient Synagogue With Unique Mosaic Floor Found In Galilee
Mosaic floor found at site of newly discovered Galilee synagogue shows workman with woodworking tool. (Credit: Gabi Laron, Hebrew University Institute of Archaeology)
Remains of an ancient synagogue from the Roman-Byzantine era have been revealed in excavations carried out in the Arbel National Park in the Galilee under the auspices of the Hebrew University of Jerusalem.
The excavations, in the Khirbet Wadi Hamam, were led by Dr. Uzi Leibner of the Hebrew University's Institute of Archaeology and Scholion -- Interdisciplinary Research Center in Jewish Studies.
Dr. Leibner said that the synagogue's design is a good example of the eastern Roman architectural tradition. A unique feature of the synagogue is the design of its mosaic floor, he said.
The synagogue ruins are located at the foot of the Mt. Nitai cliffs overlooking the Sea of Galilee, amidst the remains of a large Jewish village from the Roman-Byzantine period. The first season of excavations there have revealed the northern part of the synagogue, with two rows of benches along the walls. The building is constructed of basalt and chalk stone and made use of elements from an earlier structure on the site.
Archaeologists differ among themselves as to which period the ancient Galilean synagogues belong. The generally accepted view is that they can be attributed to the later Roman period (second to fourth centuries C.E.), a time of cultural and political flowering of the Jews of the Galilee. Recently, some researchers have come to believe that these synagogues were built mainly during the Byzantine period (fifth and sixth centuries C.E.), a time in which Christianity rose to power and, it was thought, the Jews suffered from persecution. Dr. Leibner noted that this difference of scholarly opinion has great significance in perhaps redrawing the historical picture of Jews in those ancient times.
The excavators were surprised to find in the eastern aisle of the synagogue a mosaic decoration which to date has no parallels -- not in other synagogues, nor in art in Israel in general from the Roman-Byzantine period. The mosaic is made of tiny stones (four mm. in size) in a variety of colors. The scene depicted is that of a series of woodworkers who are holding various tools of their trade.
Near these workers is seen a monumental structure which they are apparently building. According to Dr. Leibner, since Biblical scenes are commonly found in synagogue art, it is possible that what we see in this case is the building of the Temple, or Noah's ark, or the tower of Babel. The mosaic floor has been removed from the excavation site and its now in the process of restoration.
The archaeologists at the site are also attempting, though their excavations, to gain a clearer picture of rural Jewish village life in Roman-era Galilee. In addition to excavating the synagogue, they also are involved in uncovering residential dwellings and other facilities at the site, such as a sophisticated olive oil press and solidly-built two-story homes.
"There are those who tend to believe that the rural Jewish villagers of that era lived in impoverished houses or in huts and that the magnificent synagogues existed in contrast to the homes that surrounded them," said Dr. Leibner. 'While it is true that the synagogues were built of a quality that exceeded the other structures of the village, the superior quality private dwellings here testify to the impressive economic level of the residents."
Participating in the excavations were students from the Hebrew University Institute of Archaeology, Jewish youth groups from abroad and many other volunteers.
Publicado por Nathaniel en 8:12 No hay comentarios:
Roman Temple Uncovered In Ancient Jewish Capital Of Galilee
View of the monumental building on the north side of the decumanus with a pile of collapsed columns in the courtyard -- probably the result of an earthquake. (Credit: Gaby Laron)
Ruins of a Roman temple from the second century CE have recently been unearthed in the Zippori National Park. Above the temple are foundations of a church from the Byzantine period.
The excavations, which were undertaken by the Noam Shudofsky Zippori Expedition led by of Prof. Zeev Weiss of the Institute of Archaeology at the Hebrew University of Jerusalem, shed light on the multi-cultural society of ancient Zippori (also known as Sepphoris).
The discovery indicated that Zippori, the Jewish capital of the Galilee during the Roman period, had a significant pagan population which built a temple in the heart of the city center. The central location of the temple which is positioned within a walled courtyard and its architectural relation to the surrounding buildings enhance our knowledge regarding the planning of Zippori in the Roman era.
The building of the church on the foundation of the temple testifies to the preservation of the sacred section of the city over time. This new finding demonstrates not only the religious life, culture and society in Roman and Byzantine Zippori, but also that this was a city in which Jews, pagans and later Christians lived together and developed their hometown with various buildings.
The newly discovered temple is located south of the decumanus - colonnaded street - which ran from east to west and was the main thoroughfare in the city during the Roman through Byzantine period. The temple, measuring approximately 24 by 12 meters, was built with a decorated façade facing the street. The temple’s walls were plundered in ancient times and only its foundations remain.
No evidence has been found that reveals the nature of the temple’s rituals, but some coins dating from the time of Antoninus Pius, minted in Diocaesarea (Zippori), depict a temple to the Roman gods Zeus and Tyche. The temple ceased to function at an unknown date, and a large church, the remains of which were uncovered by the Hebrew University excavation team in previous seasons, was built over it in the Byzantine period.
North of the decumanus, opposite the temple, a monumental building was partially excavated this summer. Its role is still unclear, although its nature and size indicate that it was an important building. A courtyard with a well-preserved stone pavement of smooth rectangular slabs executed in high quality was uncovered in the center of the building, upon which were found a pile of collapsed columns and capitals - probably as a result of an earthquake. The decoration on these architectural elements was executed in stucco. Beyond a row of columns, an adjacent aisle and additional rooms were discovered. Two of them were decorated with colorful, geometrical mosaics.
Publicado por Nathaniel en 8:11 No hay comentarios:
New Evidence From Excavations In Arcadia, Greece, Supports Theory Of 'Birth Of Zeus'
Left, Dan Diffendale, research assistant, Mt. Lykaion Excavation and Survey Project, in the ash altar of Zeus trench, at the discovery of a group of Mycenaean kylikes, circa 13th century BCE. Summer 2008. Right, a small bronze hand of Zeus holding a silver lightning bolt (approximately 2 cm), circa 500 BCE, excavated at the ash altar of Zeus, Mt. Lykaion, Summer 2008. (Credit: Image courtesy of University of Pennsylvania)
In the third century BCE, the Greek poet Callimachus wrote a 'Hymn to Zeus' asking the ancient, and most powerful, Greek god whether he was born in Arcadia on Mt. Lykaion or in Crete on Mt. Ida.
A Greek and American team of archaeologists working on the Mt. Lykaion Excavation and Survey Project believe they have at least a partial answer to the poet’s query. New excavation evidence indicates that Zeus' worship was established on Mt. Lykaion as early as the Late Helladic period, if not before, more than 3,200 years ago. According to Dr. David Gilman Romano, Senior Research Scientist, Mediterranean Section, University of Pennsylvania Museum, and one of the project’s co-directors, it is likely that a memory of the cult's great antiquity survived there, leading to the claim that Zeus was born in Arcadia.
New evidence to support the ancient myth that Zeus was born on Mt. Lykaion in Arcadia has come from a small trench from the southern peak of the mountain, known from the historical period as the ash altar of Zeus Lykaios. Over fifty Mycenaean drinking vessels, or kylikes, were found on the bedrock at the bottom of the trench along with fragments of human and animal figurines and a miniature double headed axe. Also found were burned animal bones, mostly of goats and sheep, another indication consistent with Mycenaean cult activity.
“This new evidence strongly suggests that there were drinking (and perhaps feasting) parties taking place on the top of the mountain in the Late Helladic period, around 3,300 or 3,400 years ago,” said Dr. Romano.
In mainland Greece there are very few if any Mycenaean mountain-top altars or shrines. This time period — 14th-13th centuries BC — is approximately the same time that documents inscribed with a syllabic script called Linear B (an archaic form of the Greek language) first mention Zeus as a deity receiving votive offerings. Linear B also provides a word for an 'open fire altar' that might describe this altar on Mt. Lykaion as well as a word for a sacred area, temenos, a term known from later historical sources. The shrine on Mt. Lykaion is characterized by simple arrangements: an open air altar and a nearby sacred area, or temenos, which appears to have had no temple or other architectural feature at any time at this site.
Evidence from subsequent periods in the same trench indicate that cult activity at the altar seems to have continued uninterrupted from the Mycenaean period down through the Hellenistic period (4th – 2nd centuries BCE), something that has been documented at very few sites in the Greek world. Miniature bronze tripods, silver coins, and other dedications to Zeus including a bronze hand of Zeus holding a silver lightning bolt, have been found in later levels in the same trench. Zeus as the god of thunder and lightning is often depicted with a lightning bolt in his hand.
Also found in the altar trench was a sample of fulgurite or petrified lightning. This is a glass-like substance formed when lightning strikes sandy soil. It is not clear if the fulgurite was formed on the mountain-top or if it was brought to the site as a dedication to Zeus. Evidence for earlier activity at the site of the altar, from the Final Neolithic and the Early and Middle Helladic periods, continues to be found.
The Mt. Lykaion Excavation and Survey Project is a collaboration between the University of Pennsylvania Museum of Archaeology and Anthropology in Philadelphia, the University of Arizona, and the Greek Archaeological Service in Tripolis, Greece. Project directors are Dr. Romano, Dr. Mary Voyatzis of the University of Arizona, and Dr. Michalis Petropoulos, Ephor of Prehistoric and Classical Antiquties of the Greek Archaeological Service in Tripolis. The project is under the auspices of the American School of Classical Studies in Athens. Investigations at the Sanctuary of Zeus also include excavations and survey of a number of buildings and monuments from the lower sanctuary where athletic contests were held as a part of the festival for Zeus in the Archaic, Classical and Hellenistic periods. These include a hippodrome, stadium, stoa, bath, xenon (hotel building) and fountain house. The Project, which began in 2004, will continue in the summer 2009.
Support for the Mt. Lykaion Excavation and Survey Project comes from a number of foundations including the Karabots Foundation, the Samuel H. Kress Foundation, the 1984 Foundation, the Niarchos Program for the Promotion of the Hellenic Heritage at the University of Pennsylvania, as well as from numerous individual donors.
Publicado por Nathaniel en 8:09 No hay comentarios:
Brain-Machine Interfaces Make for Tricky Ethics
Direct connections from brains to computers may someday help free paralyzed people from the constraints of their bodies. They're already used to reverse deafness and blindness. But as they become more refined, brain-machine interfaces will almost certainly be used for non-therapeutic purposes — and with that expansion comes profound ethical questions.
"Whether these technologies are used in a way that's in harmony with — or an affront to — human dignity is the main question," said Adam Keiper, director of the Ethics and Public Policy Center's program on science, technology and society.
First-generation neuroelectronics are already on the market in the form of hearing aids — 150,000 people have straight-to-brain cochlear implants — and deep-brain stimulators are used to treat Parkinson's, epilepsy and even depression. Retinal implants to replace damaged eyes are in development, as are systems that enable paraplegics to control computers by thinking.
Though incredible, these technologies may someday seem rudimentary. Scientists predict that future implants will be made from engineered tissue and organic nanomaterials rather than metal, and allow for a literally seamless union of man and machine. Brain-machine interfaces could be used for entertainment or work; the U.S. military already wants to implant them in soldiers.
To some researchers, the ethical issues are not complicated. "These questions are similar to those surrounding antidepressants," said University of Tübingen bioethicist Jens Clausen, who writes about neuroelectronics in an essay published Wednesday in Nature. "We can look at discussions that have already taken place, and figure out what is relevant."
Clausen's essay focuses on the safety of implanted circuitry and brain system-tinkering. This, however, may be the easiest question to answer: Risks can be measured and weighed against possible benefits. Far trickier questions are posed by the potential off-label applications of futuristic brain-machine systems, just as steroids provoke a different discussion when injected to help hit home runs rather than being inhaled for asthma.
"The questions related to brain-machine interfaces get much more interesting when you turn to the matter of enhancement," said Keiper.
Publicado por Nathaniel en 8:06 No hay comentarios:
"Nanofoods" Offer Big Flavor, Low Fat, Stealth Vitamins
Richard A. Lovett
Imagine potato chips with all the flavor but far less sodium. Or fish oil-enriched bread that doesn't taste the least bit fishy.
These are just two ways nanotechnology is poised to enter grocery stores, a group of food scientists said at a recent meeting of the American Association for the Advancement of Science.
The potato chips would use "nanosalt"—plain-old salt crystals, only smaller, said Qasim Chaudhry, a toxicologist at Britain's Central Science Laboratory in York, England.
Together the microscopic grains have more surface area, milligram for milligram, than larger, conventional salt crystals. That means more contact with your tongue, resulting in a disproportionately salty sensation.
The same principle, Chaudhry said, applies to a type of mayonnaise currently under development in Europe.
Normal mayonnaise's tiny oil droplets add rich texture and taste. Nano-mayo instead substitutes the oil with water droplets thinly coated with oil. The result: lower fat but full flavor.
Nanotech can also be used to enrich a wide range of foods with tiny, tasteless capsules of vitamins, minerals, or health supplements.
Bread, for example, could be enhanced with heart-friendly fish oil.
Normally, that would make the bread taste, well, fishy. But with nano-supplements, "you can encapsulate it and give all the health benefits without the flavor," Chaudhry said.
In China, he added, nano forms of selenium have been used to enrich green tea to combat deficiencies in some parts of the country. More radical is the possibility of making a low-fat milkshake by coating microscopic grains of silica, a sand-like mineral, with chocolate.
The silica doesn't have any calories, and the tiny amount of chocolate is all on the surface. "When it hits the taste buds, you have huge flavor," Chaudhry said.
Not Ready for Lunch
Hermann Stamm of the European Commission's Joint Research Center in Ispra, Italy, appreciates nanofoods as a "nutritional miracle."
But he warned that the body may react differently to nanoparticles than to conventional ingredients.
Because the particles are so small, they may be able to penetrate the gut more easily. This is good for vitamins or minerals but perhaps not so good for preservatives or other synthetic chemicals.
Once in the bloodstream, nanoparticles may be able to enter cells in a wide range of organs, with unknown effects.
Even vitamins and minerals might rush into the bloodstream too quickly, causing overdoses, warned Elke Anklam, also of the Joint Research Center.
Right now nobody knows much about the safety of these products, said T. Scott Thurmond, a regulatory toxicologist with the U.S. Food and Drug Administration's Center for Food Safety and Applied Nutrition.
"It is still pretty much a crapshoot," Thurmond said. "We need to be proactive and take a look at this now to avoid any potential problems down the road."
Some nanofood products, like nanosalt, are probably safe. That's because, once the salt dissolves, nanosalt is nothing special. "It will behave like normal salt from then onward," the Central Science Laboratory's Chaudhry said.
And the fat-coated water droplets in nano-mayonnaise are likely to be safely broken apart in the gut, he said.
The Joint Research Center's Anklam agreed that anything likely to be fully digested probably poses little risk. "And we should really enjoy the mayonnaise having less fat."
Publicado por Nathaniel en 8:04 No hay comentarios:
Carbon dioxide frost
Carbon dioxide frost dusts the dunes near Mars's Proctor Crater in a recently released picture taken by the Mars Reconnaissance Orbiter.
As the red planet moves into spring, frost that accumulated during winter evaporates, although some can remain in regions sheltered from direct sunlight.
The orbiter first took pictures of these same dunes in 2006. Studying changes in an area's frost patterns over the years can help scientists better understand seasonal variability on Mars.
Publicado por Nathaniel en 8:01 No hay comentarios:
The most energetic explosion
The most energetic explosion seen so far has wowed NASA scientists, who captured the blast using the recently launched Fermi Gamma-ray Space Telescope.
The explosion, which occurred about 12.2 billion light-years away, is the first so-called gamma-ray burst Fermi has seen in high resolution. Astronomers think most gamma-ray bursts happen when very massive stars run out of fuel and collapse.
This latest burst emitted the greatest total amount of energy, had the highest initial energy output, and had the fastest moving particle jets of any known explosion.
The brilliant remnants of a supernova
The brilliant remnants of a supernova (above) were captured in a composite image by NASA's Chandra and Spitzer space observatories, which partnered with Spain's Calar Alto observatory.
The green and yellow areas represent a hot cloud of expanding debris, while the outer shock wave is in blue. The red splotches are dust radiating from the supernova.
The star explosion was witnessed by Danish astronomer Tycho Brahe and his peers in the 1500s.
Publicado por Nathaniel en 7:59 No hay comentarios:
Eclipses the sun
The moon-orbiting probe Kaguya (named for a lunar princess in Japanese folklore) snapped the high-definition footage on February 10 as Earth moved between the moon and the sun.
From our planet's surface, the lunar eclipse was barely noticeable, as the moon was moving through the outer parts of Earth's shadow—the penumbra—where only some sunlight gets blocked.
But from the moon, the disk of the Earth almost fully covered the sun. During the progression of this unusual eclipse, Kaguya caught sight of the so-called diamond ring effect.
Diamond rings are normally seen from Earth during solar eclipses. As the moon moves between the sun and Earth, slight bumps and grooves on the lunar surface cause sunlight shining from behind to "bead" around the edges.
When the moon is slightly offset from the sun, a single bead can shine brightest, creating the appearance of a gem perched on of a ring of light.
This time, though, Earth played the part of the moon, blotting out the sun from Kaguya's perspective.
Publicado por Nathaniel en 7:57 No hay comentarios:
RARE CHEETAH PHOTOS: Endangered Cats Trapped by Cameras
A male northwest African cheetah sprays urine on a tree to mark its territory during a 2008 camera survey whose results were released February 23, 2009.
Scientists hope to stave off extinction for the 250-strong subspecies. But first they need hard data--and these photos are surprising first steps, survey co-leader Sarah Durant said.
"We weren't sure we'd get any photos at all," she said. "To get so many remarkable pictures was just amazing."
Shown prowling the Sahara in 2008, this cat is the only northwest African cheetah captured in daylight during the first camera-trap survey of the subspecies in Algeria, scientists announced February 23, 2009.
Typically daytime animals, the cheetahs were likely laid low by 100-plus-degree-Fahrenheit (38-plus-degree-Celsius) temperatures, survey co-leader Sarah Durant said.
The heat and roadless terrain also took its toll on the researchers, who installed 40 camera traps in a 1,080-square-mile (2,800-square-kilometer) region.
The result: 16 sightings of four different northwestern African cheetahs.
Its eyes reflecting a flash, an extremely rare male northwest African cheetah triggers one of the first ever Algerian camera-trap pictures of this Saharan subspecies in late summer 2008.
Released February 23, the pictures represent a first step toward protecting the elusive cheetahs, which are thought to number only about 250 and are listed as critically endangered by the International Union for Conservation of Nature.
Though diminishing habitat and prey are suspected culprits, no one really knows why the subspecies is in such dire straits--which is why the camera survey is so important, said research fellow Sarah Durant of the Zoological Society of London, who co-led the project, to National Geographic News.
Publicado por Nathaniel en 7:53 No hay comentarios:
miércoles, 25 de febrero de 2009
Peruvian Citadel Is Site Of Earliest Ancient Solar Observatory In The Americas
The fortified stone temple at Chankillo. (Credit: Courtesy of Peru's National Aerophotographic Service (SAN))
Archeologists from Yale and the University of Leicester have identified an ancient solar observatory at Chankillo, Peru as the oldest in the Americas with alignments covering the entire solar year, according to an article in the March 2 issue of Science.
Recorded accounts from the 16th century A.D. detail practices of state-regulated sun worship during Inca times, and related social and cosmological beliefs. These speak of towers being used to mark the rising or setting position of the sun at certain times in the year, but no trace of the towers has ever been found. This paper reports the earliest structures that support those writings.
At Chankillo, not only were there towers marking the sun's position throughout the year, but they remain in place, and the site was constructed much earlier -- in approximately the 4th century B.C.
"Archaeological research in Peru is constantly pushing back the origins of civilization in the Americas," said Ivan Ghezzi, a graduate student in the department of Anthropology at Yale University and lead author of the paper. "In this case, the 2,300 year old solar observatory at Chankillo is the earliest such structure identified and unlike all other sites contains alignments that cover the entire solar year. It predates the European conquests by 1,800 years and even precedes, by about 500 years, the monuments of similar purpose constructed by the Mayans in Central America."
Chankillo is a large ceremonial center covering several square kilometers in the costal Peruvian desert. It was better known in the past for a heavily fortified hilltop structure with massive walls, restricted gates, and parapets. For many years, there has been a controversy as to whether this part of Chankillo was a fort or a ceremonial center. But the purpose of a 300meter long line of Thirteen Towers lying along a small hill nearby had remained a mystery..
The new evidence now identifies it as a solar observatory. When viewed from two specially constructed observing points, the thirteen towers are strikingly visible on the horizon, resembling large prehistoric teeth. Around the observing points are spaces where artifacts indicate that ritual gatherings were held.
The current report offers strong evidence for an additional use of the site at Chankillo -- as a solar observatory. It is remarkable as the earliest known complete solar observatory in the Americas that defines all the major aspects of the solar year.
"Focusing on the Andes and the Incan empire, we have known for decades from archeological artifacts and documents that they practiced what is called solar horizon astronomy, which uses the rising and setting positions of the sun in the horizon to determine the time of the year," said Ghezzi. "We knew that Inca practices of astronomy were very sophisticated and that they used buildings as a form of "landscape timekeeping" to mark the positions of the sun on key dates of the year, but we did not know that these practices were so old."
According to archival texts, "sun pillars" standing on the horizon near Cusco were used to mark planting times and regulate seasonal observances, but have vanished and their precise location remains unknown. In this report, the model of Inca astronomy, based almost exclusively in the texts, is fleshed out with a wealth of archaeological and archaeo-astronomical evidence.
Ghezzi was originally working at the site as a Yale graduate student conducting thesis work on ancient warfare in the region, with a focus on the fortress at the site.
Noting the configuration of 13 monuments, in 2001, Ghezzi wondered about a proposed relationship to astronomy. "Since the 19th century there was speculation that the 13-tower array could be solar or lunar demarcation -- but no one followed up on it," Ghezzi said. "We were there. We had extraordinary support from the Peruvian Government, Earthwatch and Yale University. So we said, 'Let's study it while we are here!'"
To his great surprise, within hours they had measurements indicating that one tower aligned with the June solstice and another with the December solstice. But, it took several years of fieldwork to date the structures and demonstrate the intentionality of the alignments. In 2005, Ghezzi connected with co-author Clive Ruggles, a leading British authority on archeoastronomy. Ruggles was immediately impressed with the monument structures.
"I am used to being disappointed when visiting places people claim to be ancient astronomical observatories." said Ruggles. "Since everything must point somewhere and there are a great many promising astronomical targets, the evidence -- when you look at it objectively -- turns out all too often to be completely unconvincing."
"Chankillo, on the other hand, provided a complete set of horizon markers -- the Thirteen Towers -- and two unique and indisputable observation points," Ruggles said. "The fact that, as seen from these two points, the towers just span the solar rising and setting arcs provides the clearest possible indication that they were built specifically to facilitate sunrise and sunset observations throughout the seasonal year."
What they found at Chankillo was much more than the archival records had indicated. "Chankillo reflects well-developed astronomical principles, which suggests the original forms of astronomy must be quite older," said Ghezzi, who is also the is Director of Archaeology of the National Institute of Culture in Lima, Peru.
The researchers also knew that Inca astronomical practices in much later times were intimately linked to the political operations of the Inca king, who considered himself an offspring of the sun. Finding this observatory revealed a much older precursor where calendrical observances may well have helped to support the social and political hierarchy. They suggest that this is the earliest unequivocal evidence, not only in the Andes but in all the Americas, of a monument built to track the movement of the sun throughout the year as part of a cultural landscape.
According to the authors, these monuments were statements about how the society was organized; about who had power, and who did not. The people who controlled these monuments "controlled" the movement of the sun. The authors pose that this knowledge could have been translated into the very powerful political and ideological statement, "See, I control the sun!"
"This study brings a new significance to an old site," said Richard Burger, Chairman of Archeological Studies at Yale and Ghezzi's graduate mentor. "It is a wonderful discovery and an important milestone in Andean observations of this site that people have been arguing over for a hundred years."
"Chankillo is one of the most exciting archaeoastronomical sites I have come across," said Ruggles. "It seems extraordinary that an ancient astronomical device as clear as this could have remained undiscovered for so long."
Ghezzi is also a Lecturer in Archaeology at Pontificia Universidad Catolica del Peru in Lima, Peru. Support for the project came from Yale University, the Pontificia Universidad Católica del Peru, the National Science Foundation, the Wenner-Gren Foundation, the Field Museum, the Schwerin Foundation, Earthwatch Institute and the Asociación Cultural Peruano Británica in Lima, Peru.
Publicado por Nathaniel en 10:58 No hay comentarios:
A paleolimnological perspective on industrial-era metal pollution in the central Andes, Peru
Scientists in the United States and Canada are reporting the first scientific evidence that ancient civilizations in the Central Andes Mountains of Peru smelted metals, and hints that a tax imposed on local people by ancient Inca rulers forced a switch from production of copper to silver.
Their study is scheduled for the May 15 issue of ACS' Environmental Science & Technology, a semi-monthly journal.
The University of Alberta's Colin A. Cooke and colleagues point out that past evidence for metal smelting, which involves heating ore to extract pure metal, was limited mainly to the existence of metal artifacts dating to about 1,000 A.D. and the Wari Empire that preceded the Inca. The new evidence emerged from a study of metallurgical air pollutants released from ancient furnaces during the smelting process and deposited in lake sediments in the area.
By analyzing metals in the sediments, the researchers recreated a 1,000-year history of metal smelting in the area, predating Francisco Pizarro and his Spanish conquistadors by 600 years. Their findings show that smelters in the Morococha region of Peru switched from production of copper to silver around the time that Inca rulers imposed a tax, payable in silver, on local populations.
Publicado por Nathaniel en 10:55 No hay comentarios:
Ancient Blood Found On Sculptures From Kingdom Of Mali
A new, highly-sensitive analytical test was used to confirm the presence of blood in the coating of this animal-like artifact used in ancient Mali rituals. (Credit: Pascale Richardin, Center for Research and Restoration for the Museums of France)
Scientists in France are reporting for the first time that sculptors from the fantastically wealthy ancient Empire of Mali -- once the source of almost half the world's gold -- used blood to form the beautiful patina, or coating, on their works of art. Pascale Richardin and colleagues describe development of a new, noninvasive test that accurately identifies traces of blood apparently left on ancient African artifacts used in ceremonies involving animal sacrifices.
Archaeologists often had reported or suspected the presence of blood on many African artifacts, the study points out. However, accurately identifying the presence of blood was difficult because of the tiny amounts of blood remaining over the ages.
The researchers describe use of three highly sensitive tests -- time-of-flight secondary ion mass spectrometry, infrared microscopy, and X-ray microfluoresence -- to identify iron-bound (the chemical fingerprint of blood) on the patina from seven Dogon and Bamana sculptures from Mali. The technique, which caused virtually no damage to priceless artworks, also is suitable for identification of blood on other ancient artifacts, the study states.
The article "Identification of Ritual Blood in African Artifacts using TOF-SIMS and Synchrotron Radiation Microspectroscopies" is scheduled for the Dec. 15 issue of ACS' Analytical Chemistry.
Publicado por Nathaniel en 10:53 No hay comentarios:
Origins Of Pompeii-style Artifacts Examined
Roman artefacts which are nearly two thousand years old with similarities to ancient remains found at Pompeii in Italy have been examined at the Science and Technology Facilities Council's ISIS neutron source (21-22 February). Researchers are hoping to learn more about our heritage by discovering whether the items were imported from southern Italy, or manufactured using similar techniques in Britain.
The bronze artefacts, which include a wine-mixing vessel, jugs and ceremonial pan-shaped objects, were discovered in Kent in two high status Roman pit-burials that are among the best examples ever seen in Britain. Previous excavation in an area close to the A2 where the items were found - by construction group Skanska Civil Engineering during a Highways Agency road improvement scheme - had predicted archaeological discoveries, but they were bigger than expected, with settlements ranging from the Bronze Age to the late medieval period.
Archaeological scientists have been comparing the 1st Century AD artefacts from Kent with those from Pompeii in Italy. The neutron beams at the world-leading ISIS facility allow for detailed crystal structure analysis of intact delicate objects without cutting out a sample of the material.
Dana Goodburn-Brown, a conservator and ancient metals specialist commissioned by Oxford Archaeology, has been analysing the artefacts along with archaeological scientist Dr. Evelyne Godfrey at ISIS to see how they were made. It is hoped results from the experiments will answer many questions about how the items were made to give more insight into their origin: for example, the metals used in manufacturing, how they were cast and finished, and how metal pieces were joined together.
''Our experiments will hopefully aid us in characterising different Roman metalworking practices and perhaps recognising the distinction between imported south Italian goods and high standard copies produced by skilled local craftsman. These artefacts represent a time of great change in Britain - they appear shortly after the Romans arrived in this country, and may represent locals taking on cultural practices of these 'newcomers," Dana Goodburn-Brown said.
Dr Andrew Taylor, ISIS Director said: "For these rare and highly-valued objects, analysis with neutrons can give fantastic insight. Neutrons are a very powerful way to look at matter at the molecular level and they give unique results that you can't easily get with any other technique. The measurements are extremely delicate and non-destructive, so the objects are unharmed by the analysis and can be returned to the museums unscathed.
The neutron beams we have at ISIS are a very versatile research tool and we're always keen to help researchers answer a broad range of questions. Here we realised that we could take the same analysis methods we developed to look at parts of aircraft and power plants and use them to help archaeologists understand how ancient objects were traded and manufactured."
Publicado por Nathaniel en 10:52 No hay comentarios:
Alaska Coasts Melting -- And Not Just the Ice
Part of Alaska's coast is drifting into the sea at twice the rate it has in the past, reshaping the Arctic shoreline, a new study says.
The trend could seriously threaten the area's caribou and other wildlife, as well as local landmarks that document human settlements.
Some stretches of the state's northern shore along the Beaufort Sea receded by more than 80 feet (25 meters) in summer 2007 alone, when Arctic sea ice was at a record low.
In the past, spurts of erosion had often been linked to storms, but there were no major storms in 2007. That suggests "a shift in the forces driving erosion," said lead author Benjamin Jones, a research geographer at the U.S. Geological Survey.
One major force now is global warming, according to the research.
The study of the 40-mile (64-kilometer) stretch of coast was published this week in the journal Geophysical Research Letters.
Out to Sea
Warming air and sea temperatures are melting the ice in the region's permafrost, or perpetually frozen earth. The meltwater then streams over the land and melts more permafrost, carrying sediment into the sea as it goes.
From 2002 to 2007, the melting ice caused the coast to disappear at a rate of about 45 feet (14 meters) a year. That's up from an annual average of 30 feet (9 meters) between 1979 and 2002 and 20 feet (6 meters) between 1955 and 1979.
Remains of the ghost town of Esook, a hundred-year-old trading post, have been buried underwater as a result of the erosion, Jones said.
And near the town of Lonely, Jones took a picture of a whaling boat that a few months later was swallowed by the sea after nearly a century on shore.
The erosion also threatens oil wells. At least one has already been lost since 2002, and another will soon be gone, if the melting continues at these rates.
Larry Hinzman, director of the International Arctic Research Center in Fairbanks, Alaska, said the permafrost in this region has a considerable amount of ice, which is one reason it is melting so fast.
"If it were a different soil type, it would have less ice and would not erode so quickly," said Hinzman, who was not involved with the research.
Hinzman said the findings "would not be representative of the whole Arctic, but there are many places in the Arctic where the permafrost does contain similarly massive amounts of ice.
"This is not an unusual landscape feature in Alaska, Canada, or Siberia, but it would be unusual in Greenland, Iceland, and [the Swedish archipelago] Svalbard," he said.
The researchers call for more study of the erosion patterns so that preservation plans can be devised and new development can avoid early demise.
"Erosion is a natural process, and it is likely that this coastline has experienced erosion for quite some time," Jones said. It's the speed at which it is now occurring that worries researchers.
Publicado por Nathaniel en 10:50 No hay comentarios:
NASA Satellite Crashes Back to Earth
The rocket carrying NASA's Orbiting Carbon Observatory (OCO) suffered a technical glitch early this morning that caused the satellite to crash into the ocean near Antarctica.
In development for nine years, the observatory was meant to orbit Earth and monitor global carbon dioxide emissions.
Data from the satellite would have helped researchers better understand distribution of the greenhouse gas, possibly improving climate models. (Get the facts on global warming.)
NASA officials are now calling the $270-million mission a total loss.
"Certainly for the science community, it's a huge disappointment," Michael Freilich, director of NASA's Earth Science Division in Washington, D.C., said this morning at a briefing.
"OCO was an important mission to measure important elements of the carbon cycle."
The Taurus XL rocket carrying the OCO successfully launched at 4:55 a.m. ET from the Vandenberg Air Force Base in California.
Countdown had proceeded normally except for one non-threatening and unrelated glitch, said Chuck Dovale, NASA launch director for the mission.
"We did have stage-zero ignition," Dovale said, referring to the initial firing of the rocket's launch boosters.
Three minutes after liftoff, NASA officials began to get hints that something was wrong.
Computers on Earth sent the proper signals for the rocket to shed the clamshell structure housing the satellite, but the device failed to separate.
"As a direct result of carrying that extra weight, we could not make orbit," said John Brunschwyler, a program manager with Orbital Sciences Corporation, which built the Taurus rocket for NASA.
NASA's Dovale called the failure a "huge disappointment for the entire team."
An inquiry will be organized to study the failure, NASA officials said, and the agency will be evaluating the best way to proceed with its Earth-observing goals.
Publicado por Nathaniel en 10:49 No hay comentarios:
Weird Fish With Transparent Head
With a head like a fighter-plane cockpit, a Pacific barreleye fish shows off its highly sensitive, barrel-like eyes--topped by green, orblike lenses--in a picture released today but taken in 2004.
The fish, discovered alive in the deep water off California's central coast by the Monterey Bay Aquarium Research Institute (MBARI), is the first specimen of its kind to be found with its soft transparent dome intact.
The 6-inch (15-centimeter) barreleye (Macropinna microstoma) had been known since 1939--but only from mangled specimens dragged to the surface by nets.
The beady bits on the front of the Pacific barreleye fish in this picture released February 23, 2009, aren't eyes but smell organs.
The grayish, barrel-like eyes are beneath the green domes, which may filter light. In this picture the eyes are pointing upward--the better to see prey above in the darkness of the barreleye's deep-sea home.
Since the eyes are upright tubes, "it just looked like [they only] looked straight up," MBARI marine technician Kim Reisenbichler said. But by watching live fish from a remotely operated vehicle (ROV) and by bringing a barreleye to an aquarium for study, the scientists discovered that the eyes can pivot, like a birdwatcher pointing binoculars.
The transparent-headed Pacific barreleyes may steal fish from siphonophores (such as this one photographed in 2001)—jellies that can grow to more than 33 feet (10 meters) long, according to researchers who released new barreleye findings and pictures on February 23, 2009.
The barreleye's flat, horizontal fins may allow it to swim very precisely among the siphonophore's stinging tentacles—and if the fish fumbles, the clear, helmet-like shield may protect its eyes, according to MBARI scientists
The barreleye lives more than 2,000 feet (600 meters) beneath the ocean's surface, where the water is almost inky.
The transparent-headed fish spends much of its time motionless, eyes upward, MBARI scientists discovered while watching the barreleye fish from a remotely operated vehicle.
The green lens atop each of the fish's eyes filters out what little sunlight makes it down from the surface, allowing the fish to focus on the bioluminescence of small jellies or other prey passing overhead.
Then the eyes rotate forward to follow the prey, allowing the fish to home in on its meal.
Publicado por Nathaniel en 10:44 No hay comentarios:
martes, 24 de febrero de 2009
Surprise! That Comet Is an Asteroid, Sort Of
Two years ago, NASA's Stardust mission returned to Earth with a payload of comet dust, harvested from the small Wild 2 Comet. Researchers are still studying what the probe brought back, and now say the little comet barely looks like a comet at all.
By early last year, they'd realized that a good portion of the dust returned by Stardust seemed to have formed close to our own young Sun, rather than originating with other stars or elsewhere in the universe. That was a first surprise, since comets are generally believed to be a kind of time capsule, holding stardust and other ancient material predating the creation of our own solar system.
Now researchers say that the Wild 2 sample seems to be strangely devoid of any of this pre-solar material that they expected. As such, it looks much more like a piece of rock coming from the Asteroid Belt, rather than a conventional comet.
"The material is a lot less primitive and more altered than materials we have gathered through high altitude capture in our own stratosphere from a variety of comets," said (Lawrence Livermore National Laboratory's) Hope Ishii. "As a whole, the samples look more asteroidal than cometary."
So was there a mistake? Is Wild 2 just an asteroid that strayed into the cometary Kuiper Belt sometime early in the solar system's history, and has fooled scientists since. Turns out the answer isn't so simple.
Wild 2 gets to keep its designation as a comet, because it has a tail of vaporizing ices. But these findings show that researchers can't draw a black-and-white line between comets and asteroids, Ishii says. In fact, there may be a spectrum, or continuum of objects that share traits once thought to define one or the other.
A paper on the research is being published in the Jan. 25 edition of Science.
Publicado por Nathaniel en 11:39 No hay comentarios:
Rare Comet Close-Up Coming to a Sky Near You
NASA's Swift Gamma-Ray Explorer satellite took this shot of Comet Lulin on Jan. 28, and regular folks may be able to catch their own glimpse with binoculars on February 23.
The image was taken as the comet was passing through the constellation Libra, 100 million miles from Earth and 115 million miles from the sun. It combines data from Swift's optical and ultraviolet telescope (the blue colors) and its X-ray telescope (red). The star-field background comes from a Digital Sky Survey image.
Lulin's tail — grit and grains from the comet's rock-and-ice surface pushed off into space by solar radiation — extends to the right. Lulin is shedding 800 gallons of water every second, according to NASA astronomers. That's enough to fill an Olympic-size swimming pool in less than 15 minutes.
Solar radiation also breaks comet water down into hydroxyl particles, composed of one oxygen and one hydrogen atom. Swift determined that the hydroxyl cloud around Lulin is about 250,000 miles wide, slightly greater than the distance from the Earth to the moon.
Lulin, discovered in July 2007, is now visible to the naked eye in dark, rural skies. But the view will get better: On the night of Feb. 23, Lulin will pass within 38 million miles of Earth, appearing about 2 degrees south-southwest of Saturn in the night sky. Stargazers with binoculars should get a good look. By mid-March, Lulin will have zoomed off into deep space and out of sight.
Publicado por Nathaniel en 11:37 No hay comentarios:
X-rays Used To Reveal Secrets Of Famous 'Dinobird' Fossil
About 150 million years ago, an evolutionarily hybrid creature, a dinosaur on its way to becoming a bird, died in what is now Germany, and become fossilized in limestone.
About 150 years ago, the fossil of this "dinobird" was discovered and celebrated as proof of Charles Darwin's new theory of evolution.
Now fast word to a few weeks ago: The famous fossil, the Thermopolis specimen of Archaeopteryx lithographica, made its way by truck from the Wyoming Dinosaur Center to the Stanford Synchrotron Radiation Lightsource in California, where it was meticulously scanned by one of the world's most powerful X-ray machines, a building-sized device created for physics research.
By looking for traces of specific elements left in the slab of limestone as the bird decomposed, the researchers hope to uncover heretofore-unseen details of the soft tissue that once surrounded the well-preserved bones.
The X-rays, generated by SSRL's high-speed electrons as they race around a 260-foot-diameter ring, cause the elements to glow, revealing the ghost of soft tissue or feathers.
"If you want to find a single fossil which is a missing link in the evolution of dinosaurs into birds, this is it," said University of Manchester paleontologist Phil Manning, a member of the research team. "It's a bird with sharp teeth, claws and a long bony tail. If you were to freeze-frame evolution, you would end up with Archaeopteryx."
"What you normally can't see are the chemical elements from the original organism that might still be present in the fossil," said SSRL scientist Uwe Bergmann. "Using X-ray fluorescence imaging, we can bring these elements to light, getting a better look at the fossil and learning more about the original animal."
"These X-rays work a thousand time better than what you could do with a commercial X-ray machine. Only a synchrotron can do this," Bergmann said. SSRL is part of SLAC National Accelerator Laboratory, which is operated by Stanford University for the Department of Energy.
In addition to offering a new view of a long-extinct animal, this work may also reveal more about fossilization itself. By understanding how fossilization occurs and what exactly is preserved in the process, researchers will be able to deduce much more about ancient organisms and evolution.
The Archaeopteryx fossil holds a unique place in history. It was brought to London soon after Darwin published his stunning On the Origin of Species in 1859. With perfect timing, the old bones played a major roll in the controversy Darwin had stirred up.
"This fossil was the savior of Darwin," Manning said. "As soon as it arrived in London, all of Darwin's supporters realized that this was an intermediate animal, an evolutionary freak that they needed to study. It was half way between dinosaur and bird. This is the single most important fossil in paleontology for that simple reason.
" It was used to beat the living daylights out of the nonsense which had been put forward as to the reason for why animals were present on this planet. Here, Darwin's theory of descendant with modification was hammered home with this one example of transitionary form, of an animal between dinosaur and bird."
The fossil research is one example of how the SSRL is shining new light on fields as diverse as paleontology, medicine, and the history of mathematics. The SSRL's hair-thin X-ray beam has been used, for example, to make visible the hidden writing in a medieval copy of a mathematical treatise from the Greek mathematician Archimedes. Tuned to specific energies, the X-rays produced images of phosphorus and calcium from the ink used on the papyrus document, which had been covered with paint.
Earlier this year, at the request of Stanford library officials and an academic researcher, the laser-like X-ray beam was used to scan a score by the Italian composer Luigi Cherubini (1760 – 1842). Portions of the work had been covered over with carbon-black ink, but after the scan, "The researcher was able to look right through the ink and read the score," said Mary Miller, a Stanford preservation librarian. "I think he was thrilled."
"This is the very infancy of this new scientific method," said paleontologist Peter Larson of the Black Hills Institute in South Dakota. "We don't even know enough about this to know the right questions to ask yet. All of a sudden, we can look at fossils in a very different and new way."
Publicado por Nathaniel en 11:33 No hay comentarios:
Six Real-Life WALL-Es That Could Save the Earth
Pollen-Robo's luminous "eyes" cycle through five colors depending on the area's pollen count. The balloon-like robots were developed in 2006 to warn Japanese residents of impending hayfever attacks--16 percent of the nation's population suffers from pollen allergies.
Each Pollen-Robo, developed by forecaster Weathernews Inc., is 11.8 inches (30 centimeters) wide and weighs about two pounds (one kilogram).
The pollution-monitoring bots hang outside homes, absorbing the same volume of air that a person breathes. They relay pollen, temperature, air pressure, and humidity data to Weathernews for its online pollen alert map.
Like a real-life version of the title robot from the Oscar-nominated film WALL-E, Pollen-Robos are among the droids tackling the world's environmental jobs. Such machines are reducing greenhouse gas emissions, patrolling the Amazon, and mopping up radioactive waste.
Here's a look at some of the "green" machines in development today and how they can help save the planet.
Hauling yourself up a 100-foot-tall (30-meter-tall) rotor blade is no easy task. But with more wind turbines being built to offer sustainable energy, there's a growing need for robust maintenance workers. That's where RIWEA robots come in.
In development at Germany's Fraunhofer Institute for Factory Operation and Automation, RIWEA can automatically climb turbines and check every inch of the blades for surface defects using a thermal camera.
RIWEA also uses ultrasound to find deeper flaws that no human maintenance worker would be able to see.
According to the World Wind Energy Association, total wind-power generation, at 260 terawatt hours, now equals about 1.5 percent of global electricity use.
Chico Mendes campaigned to save the Amazon rain forest from logging and ranchers before he was shot dead in 1988. Today the activist's legacy lives on in the form of amphibious robots that patrol the Amazon River Basin.
Brazilian energy giant Petrobras developed the 5-foot-long (1.5-meter-long) "Chicos" in 2007 in conjunction with socio-environmental research program Piatam. The project aims to help Petrobras meet its environmental requirements while constructing a 261-mile (420-kilometer) gas pipeline along the Solimões River.
The remote-operated, solar-powered machines roam the basin collecting data on water chemistry as well as imagery and sound recordings that reveal any industrial impacts.
"The challenge was to create a tool that could reach the key spots in the habitat without causing greater harm," said project coordinator and bot creator Rey Robinson Salvi dos Reis, above. "We needed a device that could travel this terrain and show us what is in its path."
Traffic collisions claim the lives of tens of thousands of people annually in the U.S.--and generate tons of waste from wrecked vehicles and clouds of emissions from traffic backups. Nissan Motors wants to halve the accidents its vehicles are involved in by 2015, and car company execs think robotic technology inspired by nature can help do the job.
Demonstrated using small robots last year, the Biomimetic Car Robot Drive was designed based on the compound eyes and 300-degree vision of bumblebees. The sensors use laser range-finders to detect obstacles up to 6.5 feet (2 meters) away.
Once installed in a vehicle, "the split second [the sensors] detect an obstacle, the car robot will mimic the movements of a bee and instantly change direction by turning [the car's] wheels at right angles or greater to avoid a collision," said Nissan's Toshiyuki Ando.
"The biggest difference to any current system is that the avoidance maneuver is totally instinctive."
Lawn mower engines have not been subject to the same emission-control regulations as cars, according to the U.S. Environmental Protection Agency. Yard work has therefore played a significant role in the formation of ground-level ozone due to mower emissions of carbon monoxide, hydrocarbons, and nitrogen oxides.
Sweden-based firm Husqvarna's solution is the Automower Solar Hybrid, the world's first automatic lawn mower partly powered by sunlight.
On sale this year, the unit can cover up to 22,600 square feet (2,100 square meters), and can even tackle slopes.
The hybrid helper operates for up to an hour on a 45-minute battery charge--longer if it's sunny--before returning to its charging station. The only things it emits are grass cuttings.
Like lonely WALL-E, left behind to clean up a garbage-coated Earth, the Possum is sent to scrub aging radioactive waste storage tanks where humans dare not linger.
The Possum, developed by GE Inspection Technologies, is so named because it's lowered tail-down through 12-inch (30-centimeter) access ports into the underground tanks.
The bot is remote-controlled and equipped with a camera so operators can take pictures of the tank interior and locate waste for cleanup.
Once the device is maneuvered into position, it wields its scoop to transfer the waste into a container. Inspectors can then determine what sort of material it is and how much of it remains in the tank.
Publicado por Nathaniel en 11:25 No hay comentarios:
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