A 3.3 million-year-old skeleton of the earliest child ever found shows the ancient ancestor of modern humans walked upright but may also have climbed trees, scientists said on Wednesday.
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They found the well-preserved remains of a three-year-old girl of the species Australopithecus afarensis -- which includes the fossil skeleton known as "Lucy" -- in the Dikika area of Ethiopia, 400 kms northeast of the capital Addis Ababa.
"It represents the earliest and most complete partial skeleton of a child ever found in the history of paeleoanthropology," said Dr Zeresenay Alemseged, of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.
The skull, torso and upper and lower limbs, including the hand, show both human and ape-like features. The state of the ancient bones suggest she was buried in a flood which may also have caused her death.
The remains provide the first evidence of what babies of early human ancestors looked like. The nearly complete skeleton will also provide information about the child's height and structure.
"This child will help us understand a lot about the species to which it belongs," said Alemseged, leader of the international team of scientists who reported the findings in the journal Nature.
"The lower part of the body, which includes the foot, the shin bone and the thigh bone clearly shows us that this species was an upright walking creature," he told Reuters.
But some of the features from the upper part of the body, including the shoulder blade and arms are more ape-like. The fingers are long and curved which suggest she might have been able to swing through trees.
"The finding is the most complete hominid skeleton ever found in the world," Zeresenay Alemseged, who is head of the Paleoanthropological Research Team, told a news conference in Addis Ababa.
He said the fossil was older than the 3.2-million-year-old remains of "Lucy" discovered in 1974 and described by scientists as one of the world's greatest archaeological finds.
"The new bones belong to a three-year-old girl who lived 3.3 million years ago, 150,000 years before Lucy," Zeresenay said.
The fossil has been named "Selam," which means peace in Ethiopia's official Amharic language.
JUVENILE "LUCY"
Dr Simon Underdown of Oxford Brookes University in England described it as a massively exciting discovery of a juvenile "Lucy." "This tremendous fossil will make us challenge many of the ideas we have about how and why we came to walk on two feet," he said.
An analysis of the sediment in which the remains were found enabled researchers to build a picture of the type of environment in which the child lived.
It was a lush area with flowing water, forests and grassland which was also affected by volcanic eruptions. The range of habitats was suitable for hippos, crocodiles and relatives of the wildebeest.
"We can see from the sediment that the region was very much characterized by a mosaic of environment that ranged from forests and woodlands near the rivers, to seasonally flooded grasslands to a flood plain that would have supported more open vegetation," said Dr Jonathan Wynn of the University of South Florida who dated the sediments surrounding the remains.
By Patricia Reaney
Friday, September 22, 2006
Wednesday, September 13, 2006
Timeline: 50 Years of Hard Drives
Over the past five decades, hard drives have come a long way. Travel through time with us as we chronicle 50 milestones in hard-drive development--from product firsts to new technologies, and everything in between.
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1956: IBM ships the first hard drive, the RAMAC 305, which holds 5MB of data at $10,000 a megabyte. It is as big as two refrigerators and uses 50 24-inch platters. (For the full story and interviews with key players, read "The Hard Drive Turns 50.")
1961: IBM invents heads for disk drives that "fly" on a cushion of air or on "air bearings."
1963: IBM comes up with the first removable hard drive, the 1311, which has six 14-inch platters and holds 2.6MB.
1966: IBM introduces the first drive using a wound-coil ferrite recording head.
1970: General Digital Corporation (renamed Western Digital in 1971) is founded in California.
1973: IBM announces the 3340, the first modern "Winchester" hard drive, which has a sealed assembly, lubricated spindles, and low-mass heads.
1978: First RAID (Redundant Arrays of Independent Disks) technology patent is filed. (Read "How to Buy a Hard Drive: Key Features" for a description of this technology.)
1979: A group headed by Al Shugart founds disk-drive manufacturer Seagate Technology.
1979: IBM's 3370 uses seven 14-inch platters to store 571MB, the first drive to use thin-film heads.
1979: IBM's 62 PC, "Piccolo," uses six 8-inch platters to store 64MB.
1979: Seagate introduces the ST-506 drive and interface, which is then used in all early microcomputer implementations.
1980: IBM introduces the first gigabyte hard drive. It is the size of a refrigerator, weighs about 550 pounds, and costs $40,000.
1980: Seagate releases the first 5.25-inch hard disk.
1981: Shugart Associates joins NCR to develop an intelligent disk drive interface called the Shugart Associates Systems Interface (SASI), a predecessor to SCSI (Small Computer System Interface).
1982: Western Digital announces the first single-chip Winchester hard drive controller (WD1010).
1983: Rodime releases the first 3.5-inch hard drive; the RO352 includes two platters and stores 10MB.
1984: Western Digital makes the first Winchester hard drive controller card for the IBM PC/AT--and sets an industry standard.
1985: Control Data, Compaq Computer, and Western Digital collaborate to develop the 40-pin IDE interface. IDE stands for Intelligent Drive Electronics, more commonly known as Integrated Drive Electronics.
1985: Imprimis integrates the first hard drive controller into a drive.
1985: Quantum introduces the Plus Hardcard, which allows the addition of a hard drive without an available bay or a separate controller card.
1985: Western Digital produces the first ESDI (Enhanced Small Device Interface) controller board, which allows larger capacity and faster hard drives to be used in PCs.
1986: The official SCSI spec is released; Apple Computer's Mac Plus is one of the first computers to use it.
1988: Prairie Tek releases the 220, the first 2.5-inch hard drive designed for the burgeoning notebook computer market; it uses two platters to store 20MB.
1988: Connor introduces the first 1-inch-high 3.5-inch hard drive, which is still the common form factor. Before this, hard drives were either full height or half-height.
1988: Western Digital buys the disk-drive assets of Tandon Corporation with an eye to manufacturing IDE drives.
1990: Western Digital introduces its first 3.5-inch Caviar IDE hard drive.
1991: IBM introduces the 0663 Corsair, the first disk drive with thin film magnetoresistive (MR) heads. It has eight 3.5-inch platters and stores 1GB. (The MR head was first introduced on an IBM tape drive in 1984.)
1991: Integral Peripherals' 1820 Mustang uses one 1.8-inch platter to store 21MB.
1992: Seagate comes out with the first shock-sensing 2.5-inch hard drive.
1992: Seagate is first to market with a 7200-revolutions-per-minute hard drive, the 2.1GB Barracuda.
1992: Hewlett-Packard's C3013A Kitty Hawk drive uses two 1.3-inch platters to store 2.1GB.
1994: Western Digital develops Enhanced IDE, an improved hard drive interface that breaks the 528MB-throughput barrier. EIDE also allows for attachment of optical and tape drives.
1996: IBM stores 1 billion bits per square inch on a platter.
1996: Seagate introduces its Cheetah family, the first 10,000-rpm hard drives.
1997: IBM introduces the first drive using giant magneto resistive (GMR) heads, the 16.8GB Deskstar 16GP Titan, which stores 16.8GB on five 3.5-inch platters.
1998: IBM announces its Microdrive, the smallest hard drive to date. It fits 340MB on a single 1-inch platter.
2000: Maxtor buys competitor Quantum's hard drive business. At the time, Quantum is the number-two drive maker, behind Seagate; this acquisition makes Maxtor the world's largest hard drive manufacturer.
2000: Seagate produces the first 15,000-rpm hard drive, the Cheetah X15.
2002: Seagate scores another first with the Barracuda ATA V Serial ATA hard drive.
2002: A demonstration by Seagate yields a perpendicular magnetic recording areal density of 100 gigabits per square inch.
2002: Among its many 2002 technology accomplishments, Seagate successfully demos Heat-Assisted Magnetic Recording. HAMR records magnetically using laser-thermal assistance and ultimately aims to increase areal density by more than 100 times over 2002 levels.
2003: IBM sells its Data Storage Division to Hitachi, thus ending its involvement in developing and marketing disk drive technology.
2003: Western Digital introduces the first 10,000-rpm SATA hard drive, the 37GB Raptor, which is designed for the enterprise, but which gamers quickly learn is a hot desktop performer in dual-drive RAID setups.
2004: The first 0.85-inch hard drive, Toshiba's MK2001MTN, debuts. It stores 2GB on a single platter.
2005: Toshiba introduces its MK4007 GAL, which stores 40GB on one 1.8-inch platter, fielding the first hard drive using perpendicular magnetic recording.
2006: Seagate completes the acquisition of Maxtor, further narrowing the field of hard drive manufacturers.
2006: Seagate's Momentus 5400.3 notebook hard drive is the first 2.5-inch model to use perpendicular magnetic recording, which boosts its capacity up to 160GB.
2006: Seagate releases the Barracuda 7200.10, at 750GB the largest hard drive to date.
2006: Western Digital launches its 10,000-rpm Raptor X SATA hard drive, boosting its capacity to 150GB and placing a flashy transparent window that allows specially designed computer cases to showcase its inner workings.
2006: Cornice and Seagate each announce a 1-inch hard drive that holds 12GB. The drives are slated to ship in the third quarter of 2006.
Rex Farrance, PC World
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1956: IBM ships the first hard drive, the RAMAC 305, which holds 5MB of data at $10,000 a megabyte. It is as big as two refrigerators and uses 50 24-inch platters. (For the full story and interviews with key players, read "The Hard Drive Turns 50.")
1961: IBM invents heads for disk drives that "fly" on a cushion of air or on "air bearings."
1963: IBM comes up with the first removable hard drive, the 1311, which has six 14-inch platters and holds 2.6MB.
1966: IBM introduces the first drive using a wound-coil ferrite recording head.
1970: General Digital Corporation (renamed Western Digital in 1971) is founded in California.
1973: IBM announces the 3340, the first modern "Winchester" hard drive, which has a sealed assembly, lubricated spindles, and low-mass heads.
1978: First RAID (Redundant Arrays of Independent Disks) technology patent is filed. (Read "How to Buy a Hard Drive: Key Features" for a description of this technology.)
1979: A group headed by Al Shugart founds disk-drive manufacturer Seagate Technology.
1979: IBM's 3370 uses seven 14-inch platters to store 571MB, the first drive to use thin-film heads.
1979: IBM's 62 PC, "Piccolo," uses six 8-inch platters to store 64MB.
1979: Seagate introduces the ST-506 drive and interface, which is then used in all early microcomputer implementations.
1980: IBM introduces the first gigabyte hard drive. It is the size of a refrigerator, weighs about 550 pounds, and costs $40,000.
1980: Seagate releases the first 5.25-inch hard disk.
1981: Shugart Associates joins NCR to develop an intelligent disk drive interface called the Shugart Associates Systems Interface (SASI), a predecessor to SCSI (Small Computer System Interface).
1982: Western Digital announces the first single-chip Winchester hard drive controller (WD1010).
1983: Rodime releases the first 3.5-inch hard drive; the RO352 includes two platters and stores 10MB.
1984: Western Digital makes the first Winchester hard drive controller card for the IBM PC/AT--and sets an industry standard.
1985: Control Data, Compaq Computer, and Western Digital collaborate to develop the 40-pin IDE interface. IDE stands for Intelligent Drive Electronics, more commonly known as Integrated Drive Electronics.
1985: Imprimis integrates the first hard drive controller into a drive.
1985: Quantum introduces the Plus Hardcard, which allows the addition of a hard drive without an available bay or a separate controller card.
1985: Western Digital produces the first ESDI (Enhanced Small Device Interface) controller board, which allows larger capacity and faster hard drives to be used in PCs.
1986: The official SCSI spec is released; Apple Computer's Mac Plus is one of the first computers to use it.
1988: Prairie Tek releases the 220, the first 2.5-inch hard drive designed for the burgeoning notebook computer market; it uses two platters to store 20MB.
1988: Connor introduces the first 1-inch-high 3.5-inch hard drive, which is still the common form factor. Before this, hard drives were either full height or half-height.
1988: Western Digital buys the disk-drive assets of Tandon Corporation with an eye to manufacturing IDE drives.
1990: Western Digital introduces its first 3.5-inch Caviar IDE hard drive.
1991: IBM introduces the 0663 Corsair, the first disk drive with thin film magnetoresistive (MR) heads. It has eight 3.5-inch platters and stores 1GB. (The MR head was first introduced on an IBM tape drive in 1984.)
1991: Integral Peripherals' 1820 Mustang uses one 1.8-inch platter to store 21MB.
1992: Seagate comes out with the first shock-sensing 2.5-inch hard drive.
1992: Seagate is first to market with a 7200-revolutions-per-minute hard drive, the 2.1GB Barracuda.
1992: Hewlett-Packard's C3013A Kitty Hawk drive uses two 1.3-inch platters to store 2.1GB.
1994: Western Digital develops Enhanced IDE, an improved hard drive interface that breaks the 528MB-throughput barrier. EIDE also allows for attachment of optical and tape drives.
1996: IBM stores 1 billion bits per square inch on a platter.
1996: Seagate introduces its Cheetah family, the first 10,000-rpm hard drives.
1997: IBM introduces the first drive using giant magneto resistive (GMR) heads, the 16.8GB Deskstar 16GP Titan, which stores 16.8GB on five 3.5-inch platters.
1998: IBM announces its Microdrive, the smallest hard drive to date. It fits 340MB on a single 1-inch platter.
2000: Maxtor buys competitor Quantum's hard drive business. At the time, Quantum is the number-two drive maker, behind Seagate; this acquisition makes Maxtor the world's largest hard drive manufacturer.
2000: Seagate produces the first 15,000-rpm hard drive, the Cheetah X15.
2002: Seagate scores another first with the Barracuda ATA V Serial ATA hard drive.
2002: A demonstration by Seagate yields a perpendicular magnetic recording areal density of 100 gigabits per square inch.
2002: Among its many 2002 technology accomplishments, Seagate successfully demos Heat-Assisted Magnetic Recording. HAMR records magnetically using laser-thermal assistance and ultimately aims to increase areal density by more than 100 times over 2002 levels.
2003: IBM sells its Data Storage Division to Hitachi, thus ending its involvement in developing and marketing disk drive technology.
2003: Western Digital introduces the first 10,000-rpm SATA hard drive, the 37GB Raptor, which is designed for the enterprise, but which gamers quickly learn is a hot desktop performer in dual-drive RAID setups.
2004: The first 0.85-inch hard drive, Toshiba's MK2001MTN, debuts. It stores 2GB on a single platter.
2005: Toshiba introduces its MK4007 GAL, which stores 40GB on one 1.8-inch platter, fielding the first hard drive using perpendicular magnetic recording.
2006: Seagate completes the acquisition of Maxtor, further narrowing the field of hard drive manufacturers.
2006: Seagate's Momentus 5400.3 notebook hard drive is the first 2.5-inch model to use perpendicular magnetic recording, which boosts its capacity up to 160GB.
2006: Seagate releases the Barracuda 7200.10, at 750GB the largest hard drive to date.
2006: Western Digital launches its 10,000-rpm Raptor X SATA hard drive, boosting its capacity to 150GB and placing a flashy transparent window that allows specially designed computer cases to showcase its inner workings.
2006: Cornice and Seagate each announce a 1-inch hard drive that holds 12GB. The drives are slated to ship in the third quarter of 2006.
Rex Farrance, PC World
Wednesday, August 23, 2006
Russian refuses math's highest honor
A reclusive Russian won the math world's highest honor Tuesday for solving a problem that has stumped some of the discipline's greatest minds for a century — but he refused the award.
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Grigory Perelman, a 40-year-old native of St. Petersburg, won a Fields Medal — often described as math's equivalent of the Nobel prize — for a breakthrough in the study of shapes that experts say might help scientists figure out the shape of the universe.
John Ball, president of the International Mathematical Union, said that he had urged Perelman to accept the medal, but Perelman said he felt isolated from the mathematics community and "does not want to be seen as its figurehead." Ball offered no further details of the conversation.
Besides shunning the award for his work in topology, Perelman also seems uninterested, according to colleagues, in a separate $1 million prize he could win for proving the Poincare conjecture, a theorem about the nature of multidimensional space.
The award, given out every four years, was announced at the mathematical union's International Congress of Mathematicians. Three other mathematicians — Russian Andrei Okounkov, Frenchman Wendelin Werner and Australian Terence Tao — won Fields medals in other areas of mathematics.
They received their awards from King Juan Carlos to loud applause from delegates to the conference. But Perelman was not present.
"I regret that Dr. Perelman has declined to accept the medal," Ball said.
Perelman's work is still under review, but no one has found any serious flaw in it, the math union said in a statement.
The Fields medal was founded in 1936 and named after Canadian mathematician John Charles Fields. It come with a $13,400 stipend.
Perelman is eligible for far more money from a private foundation called The Clay Mathematics Institute in Cambridge, Mass.
In 2000, the institute announced bounties for seven historic, unsolved math problems, including the Poincare conjecture.
If his proof stands the test of time, Perelman will win all or part of the $1 million prize money. That prize should be announced in about two years.
The Poincare conjecture essentially says that in three dimensions you cannot transform a doughnut shape into a sphere without ripping it, although any shape without a hole can be stretched or shrunk into a sphere.
Proving the conjecture — an exercise in acrobatics with mindboggling imaginary doughnuts and balls — is anything but trivial. Colleagues say Perelman's work gives mathematical descriptions of what the universe might look like and promises exciting applications in physics and other fields.
"It is very important indeed because it really gives us an insight into geometry and in particular the geometry of the space we live in," said Oxford University math professor Marcus du Sautoy. "It does not say what the shape (of the universe) is. It just says, 'look, these are the things it could be.'"
Academics have been studying Perelman's proof since he left the first of three papers on it on a math Web site in Nov. 2002. Normal procedure would have been to seek publication in a peer-approved journal.
Three separate teams have presented papers or books explaining the details of Perelman's work, which draws heavily from a technique developed by another mathematician, Richard Hamilton of Columbia University. The Clay Mathematics Institute says the two men could conceivably share the Poincare money.
Ball said he asked Perelman if he would accept that money. Perelman said that if he won, he would talk to the Clay institute.
Perelman is believed to live with his mother in St. Petersburg. Repeated calls over many days to a telephone number listed as Perelman's went unanswered. Acquaintances refused to give out his address or the number they use to contact him, saying he did not want to talk to the media.
By DANIEL WOOLLS, Associated Press Writer
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Grigory Perelman, a 40-year-old native of St. Petersburg, won a Fields Medal — often described as math's equivalent of the Nobel prize — for a breakthrough in the study of shapes that experts say might help scientists figure out the shape of the universe.
John Ball, president of the International Mathematical Union, said that he had urged Perelman to accept the medal, but Perelman said he felt isolated from the mathematics community and "does not want to be seen as its figurehead." Ball offered no further details of the conversation.
Besides shunning the award for his work in topology, Perelman also seems uninterested, according to colleagues, in a separate $1 million prize he could win for proving the Poincare conjecture, a theorem about the nature of multidimensional space.
The award, given out every four years, was announced at the mathematical union's International Congress of Mathematicians. Three other mathematicians — Russian Andrei Okounkov, Frenchman Wendelin Werner and Australian Terence Tao — won Fields medals in other areas of mathematics.
They received their awards from King Juan Carlos to loud applause from delegates to the conference. But Perelman was not present.
"I regret that Dr. Perelman has declined to accept the medal," Ball said.
Perelman's work is still under review, but no one has found any serious flaw in it, the math union said in a statement.
The Fields medal was founded in 1936 and named after Canadian mathematician John Charles Fields. It come with a $13,400 stipend.
Perelman is eligible for far more money from a private foundation called The Clay Mathematics Institute in Cambridge, Mass.
In 2000, the institute announced bounties for seven historic, unsolved math problems, including the Poincare conjecture.
If his proof stands the test of time, Perelman will win all or part of the $1 million prize money. That prize should be announced in about two years.
The Poincare conjecture essentially says that in three dimensions you cannot transform a doughnut shape into a sphere without ripping it, although any shape without a hole can be stretched or shrunk into a sphere.
Proving the conjecture — an exercise in acrobatics with mindboggling imaginary doughnuts and balls — is anything but trivial. Colleagues say Perelman's work gives mathematical descriptions of what the universe might look like and promises exciting applications in physics and other fields.
"It is very important indeed because it really gives us an insight into geometry and in particular the geometry of the space we live in," said Oxford University math professor Marcus du Sautoy. "It does not say what the shape (of the universe) is. It just says, 'look, these are the things it could be.'"
Academics have been studying Perelman's proof since he left the first of three papers on it on a math Web site in Nov. 2002. Normal procedure would have been to seek publication in a peer-approved journal.
Three separate teams have presented papers or books explaining the details of Perelman's work, which draws heavily from a technique developed by another mathematician, Richard Hamilton of Columbia University. The Clay Mathematics Institute says the two men could conceivably share the Poincare money.
Ball said he asked Perelman if he would accept that money. Perelman said that if he won, he would talk to the Clay institute.
Perelman is believed to live with his mother in St. Petersburg. Repeated calls over many days to a telephone number listed as Perelman's went unanswered. Acquaintances refused to give out his address or the number they use to contact him, saying he did not want to talk to the media.
By DANIEL WOOLLS, Associated Press Writer
Saturday, August 12, 2006
Happy 25th Birthday to the PC
August 12, 1981. If you were ready to plunk down about $1,600, you could have owned a piece of history: The original IBM 5150 PC, generally considered to be the "first" PC.
At 25 years old, it's fun to look back on how far we've come. At 21 pounds (without drives), the 5150 wasn't much fatter than the PCs of today. Under the hood, things looked a bit different: 40KB of read-only memory and 16KB of RAM (upgradable to 256KB). You could configure the machine with one or two 160KB floppy drives, but a jack for a cassette player was included. Users certainly loved the "power-on automatic self-test of system components" and "built-in speaker for musical programming." And the keyboard (included) weighed six pounds. The 11.5-inch monochrome monitor, capable of displaying 25 lines of text, weighed in at 17 lbs. and supported both upper- and lowercase characters. Whoa.
Mock it if you must, but remember that the 5150 was unlike anything anyone had ever seen. The Apple II, released a few years earlier, came close, but it was more of a hacker toy and game-playing machine than something that would be at home in a business. The 5150 had built-in BASIC and Pascal support for writing programs, and it included a ton of business software: VisiCalc, Peachtree accounting software, and the EasyWriter word processor. And yes, Microsoft Adventure, a text-based adventure game, was available for diversions.
So that was 25 years ago. Looking ahead 25 years is almost impossible (and the further we get from the birth of the PC, the harder and harder it gets), but let's imagine. Magnetic storage will still be around, and your average hard drive will hold something in the vicinity of 30 terabytes (30,000GB) and cost $50 or less. CPU architecture will be vastly different. If we're still using silicon wafers, you could have a 32-core CPU with dedicated encryption and graphics components. In 25 years, graphics will have evolved to the point where Toy Story will seem quaint. You'll be able to compose a production like that in real time, and it'll look perfect on your wall-sized display. And dare we dream of something in true 3-D? Memo to Silicon Valley: Better get busy!
For another walk down memory lane (or rather, a walk down a lane filled with computers that predate the PC most of which you have probably never heard of), check out this page of personal computer milestones, dating back to 1950. And let's hear your memories of the early days of the personal computer. What was your first machine, and how did it change your life? The comments are open!
By Christopher Null
At 25 years old, it's fun to look back on how far we've come. At 21 pounds (without drives), the 5150 wasn't much fatter than the PCs of today. Under the hood, things looked a bit different: 40KB of read-only memory and 16KB of RAM (upgradable to 256KB). You could configure the machine with one or two 160KB floppy drives, but a jack for a cassette player was included. Users certainly loved the "power-on automatic self-test of system components" and "built-in speaker for musical programming." And the keyboard (included) weighed six pounds. The 11.5-inch monochrome monitor, capable of displaying 25 lines of text, weighed in at 17 lbs. and supported both upper- and lowercase characters. Whoa.
Mock it if you must, but remember that the 5150 was unlike anything anyone had ever seen. The Apple II, released a few years earlier, came close, but it was more of a hacker toy and game-playing machine than something that would be at home in a business. The 5150 had built-in BASIC and Pascal support for writing programs, and it included a ton of business software: VisiCalc, Peachtree accounting software, and the EasyWriter word processor. And yes, Microsoft Adventure, a text-based adventure game, was available for diversions.
So that was 25 years ago. Looking ahead 25 years is almost impossible (and the further we get from the birth of the PC, the harder and harder it gets), but let's imagine. Magnetic storage will still be around, and your average hard drive will hold something in the vicinity of 30 terabytes (30,000GB) and cost $50 or less. CPU architecture will be vastly different. If we're still using silicon wafers, you could have a 32-core CPU with dedicated encryption and graphics components. In 25 years, graphics will have evolved to the point where Toy Story will seem quaint. You'll be able to compose a production like that in real time, and it'll look perfect on your wall-sized display. And dare we dream of something in true 3-D? Memo to Silicon Valley: Better get busy!
For another walk down memory lane (or rather, a walk down a lane filled with computers that predate the PC most of which you have probably never heard of), check out this page of personal computer milestones, dating back to 1950. And let's hear your memories of the early days of the personal computer. What was your first machine, and how did it change your life? The comments are open!
By Christopher Null
Monday, August 07, 2006
Beams reveal Archimedes' hidden writings
Previously hidden writings of the ancient Greek mathematician Archimedes are being uncovered with powerful X-ray beams nearly 800 years after a Christian monk scrubbed off the text and wrote over it with prayers.
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Over the past week, researchers at Stanford University's Linear Accelerator Center in Menlo Park have been using X-rays to decipher a fragile 10th century manuscript that contains the only copies of some of Archimedes' most important works.
The X-rays, generated by a particle accelerator, cause tiny amounts of iron left by the original ink to glow without harming the delicate goatskin parchment.
"We are gaining new insights into one of the founding fathers of western science," said William Noel, curator of manuscripts at Baltimore's Walters Art Museum, which organized the effort. "It is the most difficult imaging challenge on any medieval document because the book is in such terrible condition."
Following a successful trial run last year, Stanford researchers invited X-ray scientists, rare document collectors and classics scholars to take part in the 11-day project.
It takes about 12 hours to scan one page using an X-ray beam about the size of a human hair, and researchers expect to decipher up to 15 pages that resisted modern imaging techniques. After each new page is decoded, it is posted online for the public to see.
On Friday, members of the public watched the decoding process via a live Web cast arranged by the San Francisco Exploratorium.
"We are focusing on the most difficult pages where the scholars haven't been able to read the texts," said Uwe Bergmann, the Stanford physicist heading the project.
Born in the 3rd century B.C., Archimedes is considered one of ancient Greece's greatest mathematicians, perhaps best known for discovering the principle of buoyancy while taking a bath.
The 174-page manuscript, known as the Archimedes Palimpsest, contains the only copies of treatises on flotation, gravity and mathematics. Scholars believe a scribe copied them onto the goatskin parchment from the original Greek scrolls.
Three centuries later, a monk scrubbed off the Archimedes text and used the parchment to write prayers at a time when the Greek mathematician's work was less appreciated. In the early 20th century, forgers tried to boost the manuscript's value by painting religious imagery on some of the pages.
In 1998, an anonymous private collector paid $2 million for the manuscript at an auction, then loaned it to the Walter Arts Museum for safekeeping and study.
Over the past eight years, researchers have used ultraviolet and infrared filters, as well as digital cameras and processing techniques, to reveal most of the buried text, but some pages were still unreadable.
"We will never recover all of it," Noel said. "We are just getting as much as we can, and we are going to the ends of the earth to get it."
By TERENCE CHEA, Associated Press Writer
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Over the past week, researchers at Stanford University's Linear Accelerator Center in Menlo Park have been using X-rays to decipher a fragile 10th century manuscript that contains the only copies of some of Archimedes' most important works.
The X-rays, generated by a particle accelerator, cause tiny amounts of iron left by the original ink to glow without harming the delicate goatskin parchment.
"We are gaining new insights into one of the founding fathers of western science," said William Noel, curator of manuscripts at Baltimore's Walters Art Museum, which organized the effort. "It is the most difficult imaging challenge on any medieval document because the book is in such terrible condition."
Following a successful trial run last year, Stanford researchers invited X-ray scientists, rare document collectors and classics scholars to take part in the 11-day project.
It takes about 12 hours to scan one page using an X-ray beam about the size of a human hair, and researchers expect to decipher up to 15 pages that resisted modern imaging techniques. After each new page is decoded, it is posted online for the public to see.
On Friday, members of the public watched the decoding process via a live Web cast arranged by the San Francisco Exploratorium.
"We are focusing on the most difficult pages where the scholars haven't been able to read the texts," said Uwe Bergmann, the Stanford physicist heading the project.
Born in the 3rd century B.C., Archimedes is considered one of ancient Greece's greatest mathematicians, perhaps best known for discovering the principle of buoyancy while taking a bath.
The 174-page manuscript, known as the Archimedes Palimpsest, contains the only copies of treatises on flotation, gravity and mathematics. Scholars believe a scribe copied them onto the goatskin parchment from the original Greek scrolls.
Three centuries later, a monk scrubbed off the Archimedes text and used the parchment to write prayers at a time when the Greek mathematician's work was less appreciated. In the early 20th century, forgers tried to boost the manuscript's value by painting religious imagery on some of the pages.
In 1998, an anonymous private collector paid $2 million for the manuscript at an auction, then loaned it to the Walter Arts Museum for safekeeping and study.
Over the past eight years, researchers have used ultraviolet and infrared filters, as well as digital cameras and processing techniques, to reveal most of the buried text, but some pages were still unreadable.
"We will never recover all of it," Noel said. "We are just getting as much as we can, and we are going to the ends of the earth to get it."
By TERENCE CHEA, Associated Press Writer
Wednesday, April 26, 2006
The Duke Lemur Center: New Name, New Goals
Duke University's 40-year-old home for primates is getting a makeover -- and a new name to match.
"Our new name, the Duke Lemur Center, reflects a refocusing of our scientific goals and overall mission," said Anne D. Yoder (http://dukenews.duke.edu/2006/04/yoderbio.html), the center's director since Jan. 1.
Although the center houses several types of prosimians, a suborder of primates, lemurs are the stars. "It makes sense to rename the center," Yoder said. "Its unique value lies with its collection of lemurs, which is the largest outside of their native Madagascar, an island off the southeast coast of Africa. We want to leverage this resource to benefit science."
The center will officially unveil its new name and scientific agenda on Saturday, April 29, at a celebration beginning at 5 p.m. at the center http://www.dukenews.duke.edu/2006/04/lemurfacts.html.
To support the center's reinvigoration, Duke is allocating roughly $8 million to improve and expand its facilities. Three new buildings and associated habitats will provide the lemurs with even more natural living conditions and open new opportunities for scientists to study them.
Provost Peter Lange, the university's chief academic officer, said the new name and planned investment reflect "a new direction and sense of excitement for what already is one of the treasures of Duke University. People across North Carolina and beyond know the center as a wonderful place to visit and learn about lemurs. But it also is a unique learning resource for Duke students and others who work with the animals and get involved in research projects. Simultaneously, scientists working at the center have been broadening their agenda and pursuing a wide range of exciting research questions."
For years, scientists at the center focused primarily on understanding basic lemur biology and sorting out relationships among the various species. "Our new emphasis positions lemurs as models of primate biology and evolution," Yoder said. "Lemurs are complex creatures, and their unique biology, combined with their similarities to other primates, makes them an ideal model."
Lemurs are the closest living representatives of the kinds of animals from which humans evolved, Yoder said. "Humans are evolution's experiment on lemurs," she joked, adding that "by better understanding lemurs, we better understand ourselves."
In an important research direction, the center is partnering with the Duke Institute for Genome Sciences & Policy (http://www.genomics.duke.edu/) to establish a Duke Lemur Genome Initiative. According to the institute's director, Huntington F. Willard, (http://mgm.duke.edu/faculty/willard/) one goal of the joint effort is to develop a toolkit of genome markers, distinctive segments of DNA that serve as landmarks for specific genes. To date, geneticists working on lemurs have used different markers, making it difficult to determine how different species are related to each other.
"With a standardized toolkit of genome markers, researchers should be able to greatly speed up efforts in working out the evolutionary trees of these animals," Willard said. "This will greatly assist lemur conservation efforts, as well as enhance understanding of our own evolution."
"This partnership with the Duke Lemur Center is consistent with our institute's broad efforts to explore the Genome Revolution and its consequences for life, health and society at large," he said.
Center biologists also will be able to use the genetic tools to develop active breeding programs to increase the total number of lemurs that call the center home, and to determine whether and how individual lemurs within a given population are related to each other. In the same way that DNA analysis is used to settle paternity suits, so can it be used to determine familial relationships with great accuracy. Such analyses, according to the scientists, are essential to avoid the effects of inbreeding and so maintain the genetic health of a species' population.
Across all of their research efforts, center scientists take care to ensure the animals are treated properly and studies are as noninvasive as possible. "The mantra of noninvasive research is 'do no harm," Yoder said. "For example, we take blood samples only as part of routine medical examinations." If the genome project needs blood for routine sampling, it will be stocked and used as needed. For animals without blood samples, DNA for genome analysis will be obtained using simple, safe cheek swabs.
"We must be sure to conduct our research carefully, but at the same time it is important that we study these animals," Yoder said. "They have a fascinating biology that can teach us a great deal."
For example, the genomes of brown lemurs will have different numbers of chromosomes, the structures that contain genes, with one animal having more or fewer genes than another. For brown lemurs, this trait has no harmful effects, resulting only in slight color variations. But in humans, many such chromosomal changes are highly deleterious. Center scientists hope that studying lemurs may provide insight into these conditions in humans.
Among other projects, cognitive behaviorist Elizabeth Brannon has been using lemurs to probe the connection between linguistic ability and conceptualizing numbers, running experiments in which lemurs interact with computer touch screens. The animals are not forced to participate. "They actually like to do these tasks," Yoder said. "One lemur, 'The Genius,' can't wait to start every day. He just loves it. Brannon's findings run counter to the dogma that lemurs are less intelligent than other primates. Everyone's surprised by these results."
Biologist Peter Klopfer and Andrew Krystal, director of the Duke Sleep Disorders Clinic, are studying hibernation in dwarf lemurs, which are the only primates to exhibit this trait. The National Aeronautics and Space Administration is among the groups that may be interested in the results. The agency wants to learn whether it is possible to use hibernation mechanisms to prolong human sleep during long space flights.
The center also plans to strengthen its international connections. In one current partnership, its scientists are working with Jim Vaupel of the Max Planck Institute, based in Germany. "We're looking at male versus female morbidity and mortality in lemurs," Yoder said. "Among humans, males are healthier but have shorter life spans, whereas females are just the opposite. We want to know if this relates to social structures, such as the fact that most human societies are run by dominant males. Lemur society is matriarchal, with dominant females running things. So lemurs can provide a natural experiment for comparing with humans."
The scientists also are building on activities that were established during the center's previous incarnation, by choosing carefully among projects showing the greatest promise. At one time, the center supported efforts to reintroduce endangered lemurs to Madagascar, but Yoder said this approach now is considered a costly last resort. The scientists don't rule out future efforts, she said, but they are re-evaluating the overall value of the approach.
Instead, the center is directing considerable energies to building local conservation capacity in Madagascar, by training Malagasy scientists and conservation biologists. Among their efforts, center scientists are working with institutions such as Parc Ivoloina, a regional environmental education and training facility, to train foresters and students in lemur conservation and animal rescue. "This will give the people of Madagascar the tools they need to manage and mitigate their own environmental challenges," Yoder said. Center scientists also are working with a new veterinary school in Madagascar. The Duke scientists plan to bring in specialist scholars to train Malagasy in advanced techniques, and their ultimate goal is to establish an exchange program.
The genetic toolkit to be built as part of the Duke Lemur Genome Initiative is one of the resources the center will be providing to support conservation efforts. Using the markers, scientists in various areas will be able to make genetic comparisons of different wild populations and their genomes. Such comparisons, according to center scientists, are essential for guiding conservation priorities, given the dwindling numbers of wild lemurs.
The center's planned new facilities will be instrumental in bringing to fruition the various projects under way or being planned, Yoder said.
Because the center now lacks optimal winter quarters, animals are enclosed half the year, so there is only a six-month window for studying natural behavior. Future buildings will be integrated into the surrounding forest habitat so researchers can study natural behavior year-round. During the day, animals will range freely across multi-acre enclosures of woodland, while the new buildings within the enclosures will offer animals refuge at night. As many as three species will be housed together in a single enclosure to mirror the natural situation in Madagascar.
At least one of the new buildings to be constructed will be devoted to large social groups in which animals can reproduce freely. (Many animals are now on contraception.) The substantial space and the numbers of animals will allow authentic social interactions. The building will house ring-tailed lemurs and red-ruffed lemurs, as well as another prosimian species called sifaka.
The facility is expected to be a great draw for researchers and graduate and undergraduate students. "I want them to have my experience," Yoder said. "I want others to share my excitement and inspiration." Her scientific career, she noted, was kindled by a student tour of the former primate center when she was an undergraduate at the University of North Carolina at Chapel Hill. "Such experiences can spark interest in biology and conservation, and create opportunities to introduce the science behind evolutionary biology," she said.
Another new building will provide homes to pairs of lemurs and small groups of up to four animals. It will be especially useful for scientists studying cognition and behavior, housing experiments that use minimally manipulative techniques, such as treadmills, food choice trials and simple physiological assessments. Center scientists aim to design experiments that provide the animals with enriched environments, which are healthier physically and psychologically.
To complement its research activities, the center also will get a new building geared to public outreach efforts. "Even without a lot of publicity, we had 13,000 visitors last year," Yoder said. "Now we want to do even more to educate the general public on the importance of biodiversity and evolutionary biology. The idea is to capture the imagination of the young."
Toward this aim, Heather Thomas, the center's tour coordinator, plans to develop a new exhibit featuring a replica of a Malagasy field researcher's hut. "The planned exhibit will be a reconstruction of a field station down to the tiniest detail -- excluding the mosquitoes," Yoder said. The hut will have a sleeping bag, food canteen, headlamp, field notebooks and assorted technical gear. "We expect the exhibit to help children make a connection," Yoder said. "They will be able to imagine themselves there. They'll think 'I want to do that.' "
An online "baby lemur gallery" of images and audio information about animals at the Duke Lemur Center animals is available at http://www.dukenews.duke.edu/mmedia/flash/lemurbabies.html. A high-resolution image of red ruffed lemur twins, by David Haring, can also be accessed at http://www.dukenews.duke.edu/mmedia/hires/redruffedtwins.jpg Also available in high resolution are images of: Primate Center director Anne Yoder by Duke University Photography (http://www.dukenews.duke.edu/mmedia/hires/yoderandlemur.jpg); and Duke Institute for Genome Sciences and Policy director Huntington Willard by Butch Usery (http://www.dukenews.duke.edu/mmedia/hires/willard_hunt.jpg).
- - - -
CONTACT: Monte Basgall, Duke University Office of News & Communications, 919-681-8057, monte.basgall@duke.edu
NOTE TO BROADCAST EDITORS: Duke provides an on-campus satellite uplink facility for live or pre-recorded television interviews. We are also equipped with ISDN connectivity for radio interviews. Broadcast reporters should contact the Office of Radio-TV Services at 919-681-8067 to arrange an interview.
"Our new name, the Duke Lemur Center, reflects a refocusing of our scientific goals and overall mission," said Anne D. Yoder (http://dukenews.duke.edu/2006/04/yoderbio.html), the center's director since Jan. 1.
Although the center houses several types of prosimians, a suborder of primates, lemurs are the stars. "It makes sense to rename the center," Yoder said. "Its unique value lies with its collection of lemurs, which is the largest outside of their native Madagascar, an island off the southeast coast of Africa. We want to leverage this resource to benefit science."
The center will officially unveil its new name and scientific agenda on Saturday, April 29, at a celebration beginning at 5 p.m. at the center http://www.dukenews.duke.edu/2006/04/lemurfacts.html.
To support the center's reinvigoration, Duke is allocating roughly $8 million to improve and expand its facilities. Three new buildings and associated habitats will provide the lemurs with even more natural living conditions and open new opportunities for scientists to study them.
Provost Peter Lange, the university's chief academic officer, said the new name and planned investment reflect "a new direction and sense of excitement for what already is one of the treasures of Duke University. People across North Carolina and beyond know the center as a wonderful place to visit and learn about lemurs. But it also is a unique learning resource for Duke students and others who work with the animals and get involved in research projects. Simultaneously, scientists working at the center have been broadening their agenda and pursuing a wide range of exciting research questions."
For years, scientists at the center focused primarily on understanding basic lemur biology and sorting out relationships among the various species. "Our new emphasis positions lemurs as models of primate biology and evolution," Yoder said. "Lemurs are complex creatures, and their unique biology, combined with their similarities to other primates, makes them an ideal model."
Lemurs are the closest living representatives of the kinds of animals from which humans evolved, Yoder said. "Humans are evolution's experiment on lemurs," she joked, adding that "by better understanding lemurs, we better understand ourselves."
In an important research direction, the center is partnering with the Duke Institute for Genome Sciences & Policy (http://www.genomics.duke.edu/) to establish a Duke Lemur Genome Initiative. According to the institute's director, Huntington F. Willard, (http://mgm.duke.edu/faculty/willard/) one goal of the joint effort is to develop a toolkit of genome markers, distinctive segments of DNA that serve as landmarks for specific genes. To date, geneticists working on lemurs have used different markers, making it difficult to determine how different species are related to each other.
"With a standardized toolkit of genome markers, researchers should be able to greatly speed up efforts in working out the evolutionary trees of these animals," Willard said. "This will greatly assist lemur conservation efforts, as well as enhance understanding of our own evolution."
"This partnership with the Duke Lemur Center is consistent with our institute's broad efforts to explore the Genome Revolution and its consequences for life, health and society at large," he said.
Center biologists also will be able to use the genetic tools to develop active breeding programs to increase the total number of lemurs that call the center home, and to determine whether and how individual lemurs within a given population are related to each other. In the same way that DNA analysis is used to settle paternity suits, so can it be used to determine familial relationships with great accuracy. Such analyses, according to the scientists, are essential to avoid the effects of inbreeding and so maintain the genetic health of a species' population.
Across all of their research efforts, center scientists take care to ensure the animals are treated properly and studies are as noninvasive as possible. "The mantra of noninvasive research is 'do no harm," Yoder said. "For example, we take blood samples only as part of routine medical examinations." If the genome project needs blood for routine sampling, it will be stocked and used as needed. For animals without blood samples, DNA for genome analysis will be obtained using simple, safe cheek swabs.
"We must be sure to conduct our research carefully, but at the same time it is important that we study these animals," Yoder said. "They have a fascinating biology that can teach us a great deal."
For example, the genomes of brown lemurs will have different numbers of chromosomes, the structures that contain genes, with one animal having more or fewer genes than another. For brown lemurs, this trait has no harmful effects, resulting only in slight color variations. But in humans, many such chromosomal changes are highly deleterious. Center scientists hope that studying lemurs may provide insight into these conditions in humans.
Among other projects, cognitive behaviorist Elizabeth Brannon has been using lemurs to probe the connection between linguistic ability and conceptualizing numbers, running experiments in which lemurs interact with computer touch screens. The animals are not forced to participate. "They actually like to do these tasks," Yoder said. "One lemur, 'The Genius,' can't wait to start every day. He just loves it. Brannon's findings run counter to the dogma that lemurs are less intelligent than other primates. Everyone's surprised by these results."
Biologist Peter Klopfer and Andrew Krystal, director of the Duke Sleep Disorders Clinic, are studying hibernation in dwarf lemurs, which are the only primates to exhibit this trait. The National Aeronautics and Space Administration is among the groups that may be interested in the results. The agency wants to learn whether it is possible to use hibernation mechanisms to prolong human sleep during long space flights.
The center also plans to strengthen its international connections. In one current partnership, its scientists are working with Jim Vaupel of the Max Planck Institute, based in Germany. "We're looking at male versus female morbidity and mortality in lemurs," Yoder said. "Among humans, males are healthier but have shorter life spans, whereas females are just the opposite. We want to know if this relates to social structures, such as the fact that most human societies are run by dominant males. Lemur society is matriarchal, with dominant females running things. So lemurs can provide a natural experiment for comparing with humans."
The scientists also are building on activities that were established during the center's previous incarnation, by choosing carefully among projects showing the greatest promise. At one time, the center supported efforts to reintroduce endangered lemurs to Madagascar, but Yoder said this approach now is considered a costly last resort. The scientists don't rule out future efforts, she said, but they are re-evaluating the overall value of the approach.
Instead, the center is directing considerable energies to building local conservation capacity in Madagascar, by training Malagasy scientists and conservation biologists. Among their efforts, center scientists are working with institutions such as Parc Ivoloina, a regional environmental education and training facility, to train foresters and students in lemur conservation and animal rescue. "This will give the people of Madagascar the tools they need to manage and mitigate their own environmental challenges," Yoder said. Center scientists also are working with a new veterinary school in Madagascar. The Duke scientists plan to bring in specialist scholars to train Malagasy in advanced techniques, and their ultimate goal is to establish an exchange program.
The genetic toolkit to be built as part of the Duke Lemur Genome Initiative is one of the resources the center will be providing to support conservation efforts. Using the markers, scientists in various areas will be able to make genetic comparisons of different wild populations and their genomes. Such comparisons, according to center scientists, are essential for guiding conservation priorities, given the dwindling numbers of wild lemurs.
The center's planned new facilities will be instrumental in bringing to fruition the various projects under way or being planned, Yoder said.
Because the center now lacks optimal winter quarters, animals are enclosed half the year, so there is only a six-month window for studying natural behavior. Future buildings will be integrated into the surrounding forest habitat so researchers can study natural behavior year-round. During the day, animals will range freely across multi-acre enclosures of woodland, while the new buildings within the enclosures will offer animals refuge at night. As many as three species will be housed together in a single enclosure to mirror the natural situation in Madagascar.
At least one of the new buildings to be constructed will be devoted to large social groups in which animals can reproduce freely. (Many animals are now on contraception.) The substantial space and the numbers of animals will allow authentic social interactions. The building will house ring-tailed lemurs and red-ruffed lemurs, as well as another prosimian species called sifaka.
The facility is expected to be a great draw for researchers and graduate and undergraduate students. "I want them to have my experience," Yoder said. "I want others to share my excitement and inspiration." Her scientific career, she noted, was kindled by a student tour of the former primate center when she was an undergraduate at the University of North Carolina at Chapel Hill. "Such experiences can spark interest in biology and conservation, and create opportunities to introduce the science behind evolutionary biology," she said.
Another new building will provide homes to pairs of lemurs and small groups of up to four animals. It will be especially useful for scientists studying cognition and behavior, housing experiments that use minimally manipulative techniques, such as treadmills, food choice trials and simple physiological assessments. Center scientists aim to design experiments that provide the animals with enriched environments, which are healthier physically and psychologically.
To complement its research activities, the center also will get a new building geared to public outreach efforts. "Even without a lot of publicity, we had 13,000 visitors last year," Yoder said. "Now we want to do even more to educate the general public on the importance of biodiversity and evolutionary biology. The idea is to capture the imagination of the young."
Toward this aim, Heather Thomas, the center's tour coordinator, plans to develop a new exhibit featuring a replica of a Malagasy field researcher's hut. "The planned exhibit will be a reconstruction of a field station down to the tiniest detail -- excluding the mosquitoes," Yoder said. The hut will have a sleeping bag, food canteen, headlamp, field notebooks and assorted technical gear. "We expect the exhibit to help children make a connection," Yoder said. "They will be able to imagine themselves there. They'll think 'I want to do that.' "
An online "baby lemur gallery" of images and audio information about animals at the Duke Lemur Center animals is available at http://www.dukenews.duke.edu/mmedia/flash/lemurbabies.html. A high-resolution image of red ruffed lemur twins, by David Haring, can also be accessed at http://www.dukenews.duke.edu/mmedia/hires/redruffedtwins.jpg Also available in high resolution are images of: Primate Center director Anne Yoder by Duke University Photography (http://www.dukenews.duke.edu/mmedia/hires/yoderandlemur.jpg); and Duke Institute for Genome Sciences and Policy director Huntington Willard by Butch Usery (http://www.dukenews.duke.edu/mmedia/hires/willard_hunt.jpg).
- - - -
CONTACT: Monte Basgall, Duke University Office of News & Communications, 919-681-8057, monte.basgall@duke.edu
NOTE TO BROADCAST EDITORS: Duke provides an on-campus satellite uplink facility for live or pre-recorded television interviews. We are also equipped with ISDN connectivity for radio interviews. Broadcast reporters should contact the Office of Radio-TV Services at 919-681-8067 to arrange an interview.
Friday, February 10, 2006
New Analysis Shows Three Human Migrations Out Of Africa
A, Ph.D, of Washington University in St Louis, shows three distinct major waves of human migration out of Africa instead of just two, and statistically refutes — strongly — the 'Out of Africa' replacement theory.
That theory holds that populations of Homo sapiens left Africa 100,000 years ago and wiped out existing populations of humans. Templeton has shown that the African populations interbred with the Eurasian populations — thus, making love, not war.
"The 'Out of Africa' replacement theory has always been a big controversy," Templeton said. "I set up a null hypothesis and the program rejected that hypothesis using the new data with a probability level of 10 to the minus 17th. In science, you don't get any more conclusive than that. It says that the hypothesis of no interbreeding is so grossly incompatible with the data, that you can reject it."
Templeton's analysis is considered to be the only definitive statistical test to refute the theory, dominant in human evolution science for more than two decades.
"Not only does the new analysis reject the theory, it demolishes it," Templeton said.
Templeton published his results in the Yearbook of Physical Anthropology, 2005.
A trellis, not a tree
He used a computer program called GEODIS, which he created in 1995 and later modified with the help of David Posada, Ph.D., and Keith Crandall, Ph.D. at Brigham Young University, to determine genetic relationships among and within populations based on an examination of specific haplotypes, clusters of genes that are inherited as a unit.
In 2002, Templeton analyzed ten different haplotype trees and performed phylogeographic analyses that reconstructed the history of the species through space and time.
Three years later, he had 25 regions to analyze and the data provided molecular evidence of a third migration, this one the oldest, back to 1.9 million years ago.
"This time frame corresponds extremely well with the fossil record, which shows Homo erectus expanding out of Africa then," Templeton said.
Another novel find is that populations of Homo erectus in Eurasia had recurrent genetic interchange with African populations 1.5 million years ago, much earlier than previously thought, and that these populations persisted instead of going extinct, which some human evolution researchers thought had occurred.
The new data confirm an expansion out of Africa to 700,000 years ago that was detected in the 2002 analysis.
"Both (the 1.9 million and 700,000 year) expansions coincide with recent paleoclimatic data that indicate periods of very high rainfall in eastern Africa, making what is now the Sahara Desert a savannah," Templeton said. "That makes the timing very amenable for movements of large populations through the area."
Templeton said that the fossil record indicates a significant change in brain size for modern humans at 700,000 years ago as well as the adaptation and expansion of a new stone tool culture first found in Africa and later at 700,000 years expanded throughout Eurasia.
"By the time you're done with this phase you can be 99 percent confident that there was recurrent genetic interchange between African and Eurasian populations," he said. "So the idea of pure, distinct races in humans does not exist. We humans don't have a tree relationship, rather a trellis. We're intertwined."
That theory holds that populations of Homo sapiens left Africa 100,000 years ago and wiped out existing populations of humans. Templeton has shown that the African populations interbred with the Eurasian populations — thus, making love, not war.
"The 'Out of Africa' replacement theory has always been a big controversy," Templeton said. "I set up a null hypothesis and the program rejected that hypothesis using the new data with a probability level of 10 to the minus 17th. In science, you don't get any more conclusive than that. It says that the hypothesis of no interbreeding is so grossly incompatible with the data, that you can reject it."
Templeton's analysis is considered to be the only definitive statistical test to refute the theory, dominant in human evolution science for more than two decades.
"Not only does the new analysis reject the theory, it demolishes it," Templeton said.
Templeton published his results in the Yearbook of Physical Anthropology, 2005.
A trellis, not a tree
He used a computer program called GEODIS, which he created in 1995 and later modified with the help of David Posada, Ph.D., and Keith Crandall, Ph.D. at Brigham Young University, to determine genetic relationships among and within populations based on an examination of specific haplotypes, clusters of genes that are inherited as a unit.
In 2002, Templeton analyzed ten different haplotype trees and performed phylogeographic analyses that reconstructed the history of the species through space and time.
Three years later, he had 25 regions to analyze and the data provided molecular evidence of a third migration, this one the oldest, back to 1.9 million years ago.
"This time frame corresponds extremely well with the fossil record, which shows Homo erectus expanding out of Africa then," Templeton said.
Another novel find is that populations of Homo erectus in Eurasia had recurrent genetic interchange with African populations 1.5 million years ago, much earlier than previously thought, and that these populations persisted instead of going extinct, which some human evolution researchers thought had occurred.
The new data confirm an expansion out of Africa to 700,000 years ago that was detected in the 2002 analysis.
"Both (the 1.9 million and 700,000 year) expansions coincide with recent paleoclimatic data that indicate periods of very high rainfall in eastern Africa, making what is now the Sahara Desert a savannah," Templeton said. "That makes the timing very amenable for movements of large populations through the area."
Templeton said that the fossil record indicates a significant change in brain size for modern humans at 700,000 years ago as well as the adaptation and expansion of a new stone tool culture first found in Africa and later at 700,000 years expanded throughout Eurasia.
"By the time you're done with this phase you can be 99 percent confident that there was recurrent genetic interchange between African and Eurasian populations," he said. "So the idea of pure, distinct races in humans does not exist. We humans don't have a tree relationship, rather a trellis. We're intertwined."
Thursday, October 20, 2005
Global Weather Influences And the Immediate Prospect: Season 2006
Without a troublesome pattern in the South Pacific, there is no influence to upset a normal summer pattern in the Southern Hemisphere. The winter warmth will surely be translated into summer heat. This will tend to provide a good base for the regular heat low, usually called the Barotse Low, to form early and drift gradually westward by the mid-summer. This area marks the regular base of operations for the ITCZ in southern Africa. Developing waves, after the Sahel pattern, drift westward and stagnate in the Etosha area.
The effect of the warm belt of water, offshore the West Coast, will be key. Increased warmth can bring, by insolation, even warmer waters offshore. A heat low coupling with such a favourable situation can foster a rainfall event that can last for some two to three weeks. Two such events, across January to March, will mean a wet year. The drift eastward, in tandem with a suitable cold front and upper trough, moves the rain area eastward across those areas on the eastern fringe of the previous wet zone, eventually to cross the southern subcontinent. The Congo Air factor means rains of intensity become widespread. The ready ability for Congo air to be brought southward, we have already witnessed twice during the usually unfavourable winter months. The heat low affords an attraction for the moist air circulating round the surface anticyclones to be advected inland towards the vortex: another favourable aspect.
But what about the persistent subtropical High-pressure belt? Surely, cells of this system will drift across the subcontinent some few times during the range of November through to April. The winter pattern has indicated a duration of weeks during the most favourable period (Cooler land/warmer seas). The summer season sees these cores following a more southerly track. The likelihood of our far north and northeast being consistently on the moist periphery of these cores provides a further optimistic note.
Excessive oceanic warmth can lead to two events: one very favourable for rain, the other unfavourable. The Benguela (El) Nino recurs approximately mid-decade. The cause or causes are improperly understood, but links with the Gulf of Guinea have been cited as a likely cause. Economically and ecologically, this event means turmoil and disaster. The rainfall benefits are usually plentiful. The last event peaked during February 1995. The Indian Ocean is a warm ocean by any standard. It hosts the tropical revolving storm known as a Cyclone. These storms usually develop around the Mauritius area and northward. Their tracks include the coastal waters of Madagascar and into the Mozambique Channel, on occasions.
Just occasionally, these storms make landfall and head up the Limpopo valley. They do bring considerable falls of rain to the areas in their path. But these storms are surrounded by ring of descending air (what goes up must come down syndrome) this means a zone of dry, rainless weather. People with longer memories may recall such names as Domoina and Imboia which made their dry mark during January and February 1984. The potential for these storms to drift inland as opposed to tracking southward down the Mozambique Channel is dependent upon the individual events. The Global Warming factor and its influence upon such potential is not known. A storm penetrating to the Makarikari area of Botswana will throttle active convection across northern and eastern Namibia comprehensively.
The ability to peer into the weather future is best measured in hours, rather than days. The time requirement really means months or even half a year. Much capable effort is being put into climatic forecasting. This provides percentage possibilities, across the summer month ranges, of monthly rainfall totals. In our type of climate, these efforts provide little of day-to-day practical value. When we with all our "press two buttons" capabilities have learnt to read nature and follow the preparatory signs of natural life preparing for the next season, we will be several worthy steps down the road of long-term, seasonal forecasting.
This outlook may sound very promising, or at least optimistic. The causes for this have been looked at. The dismal alternatives do not show up in the foreground. The likelihood of a dramatic, rapid turnaround of the state of the Pacific Ocean is not an event with any record. As on occasions in the past, it is an overall wait-and-see scenario.
John Olszewski
Windhoek
The effect of the warm belt of water, offshore the West Coast, will be key. Increased warmth can bring, by insolation, even warmer waters offshore. A heat low coupling with such a favourable situation can foster a rainfall event that can last for some two to three weeks. Two such events, across January to March, will mean a wet year. The drift eastward, in tandem with a suitable cold front and upper trough, moves the rain area eastward across those areas on the eastern fringe of the previous wet zone, eventually to cross the southern subcontinent. The Congo Air factor means rains of intensity become widespread. The ready ability for Congo air to be brought southward, we have already witnessed twice during the usually unfavourable winter months. The heat low affords an attraction for the moist air circulating round the surface anticyclones to be advected inland towards the vortex: another favourable aspect.
But what about the persistent subtropical High-pressure belt? Surely, cells of this system will drift across the subcontinent some few times during the range of November through to April. The winter pattern has indicated a duration of weeks during the most favourable period (Cooler land/warmer seas). The summer season sees these cores following a more southerly track. The likelihood of our far north and northeast being consistently on the moist periphery of these cores provides a further optimistic note.
Excessive oceanic warmth can lead to two events: one very favourable for rain, the other unfavourable. The Benguela (El) Nino recurs approximately mid-decade. The cause or causes are improperly understood, but links with the Gulf of Guinea have been cited as a likely cause. Economically and ecologically, this event means turmoil and disaster. The rainfall benefits are usually plentiful. The last event peaked during February 1995. The Indian Ocean is a warm ocean by any standard. It hosts the tropical revolving storm known as a Cyclone. These storms usually develop around the Mauritius area and northward. Their tracks include the coastal waters of Madagascar and into the Mozambique Channel, on occasions.
Just occasionally, these storms make landfall and head up the Limpopo valley. They do bring considerable falls of rain to the areas in their path. But these storms are surrounded by ring of descending air (what goes up must come down syndrome) this means a zone of dry, rainless weather. People with longer memories may recall such names as Domoina and Imboia which made their dry mark during January and February 1984. The potential for these storms to drift inland as opposed to tracking southward down the Mozambique Channel is dependent upon the individual events. The Global Warming factor and its influence upon such potential is not known. A storm penetrating to the Makarikari area of Botswana will throttle active convection across northern and eastern Namibia comprehensively.
The ability to peer into the weather future is best measured in hours, rather than days. The time requirement really means months or even half a year. Much capable effort is being put into climatic forecasting. This provides percentage possibilities, across the summer month ranges, of monthly rainfall totals. In our type of climate, these efforts provide little of day-to-day practical value. When we with all our "press two buttons" capabilities have learnt to read nature and follow the preparatory signs of natural life preparing for the next season, we will be several worthy steps down the road of long-term, seasonal forecasting.
This outlook may sound very promising, or at least optimistic. The causes for this have been looked at. The dismal alternatives do not show up in the foreground. The likelihood of a dramatic, rapid turnaround of the state of the Pacific Ocean is not an event with any record. As on occasions in the past, it is an overall wait-and-see scenario.
John Olszewski
Windhoek
Monday, October 17, 2005
Another Bird Link Found to Dinosaurs
Paleontologists working in northwestern Patagonia have unearthed the nearly complete skeleton of a small dinosaur whose bird-like appearance suggests that flight may have evolved twice -- not only in birds but also among the prehistoric raptors of the southern hemisphere.
The newly discovered fossil, of a rooster-sized carnivore known as a dromaeosaur, lived 95 million years ago and is the oldest raptor ever found in the southern continents. Its discovery may signal that dromaeosaurs are much older than previously thought.
"We're really just scratching the surface," said Peter Makovicky, dinosaur curator of Chicago's Field Museum and lead author of a report on the find published Wednesday in the journal Nature. "The evidence is that we have a distinct (dromaeosaurs) lineage -- the southern lineage."
Makovicky and a team of Argentine paleontologists led by Sebastian Apesteguia, of Argentina's Natural History Foundation, collected the fossil from a well-known site known as La Buitrera, "The Vulture's Nest," in Rio Negro province, about 700 miles southeast of Buenos Aires. The team named the new creature Buitreraptor gonzalezorum, after brothers Fabian and Jorge Gonzalez, who found the fossil.
Before Buitreraptor, a few teeth and other bone fragments were the only dromaeosaur remains known in the southern hemisphere. This scarcity contrasted sharply with the relatively abundant deposits in North America and Asia of such well known dromaeosaurs as velociraptor, Utahraptor and smaller species unearthed in China.
Paleontologists generally regard the northern raptors, especially the Chinese fossils, as part of the evolutionary lineage that produced modern birds. Archaeopteryx, regarded as the first true bird, is about 145 million years old, while the feathered raptors of Liaoning, China, are dated at 130 million years.
While Buitreraptor is considerably younger, its location deep in South America's southern cone suggests that dromaeosaurs generally may be 180 million years old, dating to the time when Earth's single land mass split into northern and southern pieces.
"To say dromaeosaurs are 180 million years old is not a stretch at all," said paleontologist Matthew Lamanna, of the Carnegie Museum of Natural History, in Pittsburgh. "You look at the fossil record and see Archaeopteryx is 150 million years old, so dromaeosaurs should already be around."
Makovicky noted, however, that, unlike northern dromaeosaurs, Buitreraptor has a long, heron-like skull and teeth without serrated edges, like a steak knife. "These are unusual features, and we think we have a predator of small prey," he said, possibly one that dined on small snakes prevalent in the region.
Lamanna said that the differences between the northern and southern species also come as no surprise. Once researchers established that dromaeosaurs were evolving on two separate super- continents, "the fact that they come to be different is what we would expect."
On the other hand, Makovicky said Buitreraptor is clearly a dromaeosaur, displaying many typical characteristics, including a spiked middle toe for gutting prey, heavy hind limbs for fast running, a long tail and powerful forelimbs -- but not powerful enough to fly.
Makovicky and the research team also noticed that Buitreraptor also shared characteristics with an unusual 65-million-year-old fossil from Madagascar known as Rahonavis -- thought to have been a primitive, long-tailed bird.
By Guy Gugliotta
The newly discovered fossil, of a rooster-sized carnivore known as a dromaeosaur, lived 95 million years ago and is the oldest raptor ever found in the southern continents. Its discovery may signal that dromaeosaurs are much older than previously thought.
"We're really just scratching the surface," said Peter Makovicky, dinosaur curator of Chicago's Field Museum and lead author of a report on the find published Wednesday in the journal Nature. "The evidence is that we have a distinct (dromaeosaurs) lineage -- the southern lineage."
Makovicky and a team of Argentine paleontologists led by Sebastian Apesteguia, of Argentina's Natural History Foundation, collected the fossil from a well-known site known as La Buitrera, "The Vulture's Nest," in Rio Negro province, about 700 miles southeast of Buenos Aires. The team named the new creature Buitreraptor gonzalezorum, after brothers Fabian and Jorge Gonzalez, who found the fossil.
Before Buitreraptor, a few teeth and other bone fragments were the only dromaeosaur remains known in the southern hemisphere. This scarcity contrasted sharply with the relatively abundant deposits in North America and Asia of such well known dromaeosaurs as velociraptor, Utahraptor and smaller species unearthed in China.
Paleontologists generally regard the northern raptors, especially the Chinese fossils, as part of the evolutionary lineage that produced modern birds. Archaeopteryx, regarded as the first true bird, is about 145 million years old, while the feathered raptors of Liaoning, China, are dated at 130 million years.
While Buitreraptor is considerably younger, its location deep in South America's southern cone suggests that dromaeosaurs generally may be 180 million years old, dating to the time when Earth's single land mass split into northern and southern pieces.
"To say dromaeosaurs are 180 million years old is not a stretch at all," said paleontologist Matthew Lamanna, of the Carnegie Museum of Natural History, in Pittsburgh. "You look at the fossil record and see Archaeopteryx is 150 million years old, so dromaeosaurs should already be around."
Makovicky noted, however, that, unlike northern dromaeosaurs, Buitreraptor has a long, heron-like skull and teeth without serrated edges, like a steak knife. "These are unusual features, and we think we have a predator of small prey," he said, possibly one that dined on small snakes prevalent in the region.
Lamanna said that the differences between the northern and southern species also come as no surprise. Once researchers established that dromaeosaurs were evolving on two separate super- continents, "the fact that they come to be different is what we would expect."
On the other hand, Makovicky said Buitreraptor is clearly a dromaeosaur, displaying many typical characteristics, including a spiked middle toe for gutting prey, heavy hind limbs for fast running, a long tail and powerful forelimbs -- but not powerful enough to fly.
Makovicky and the research team also noticed that Buitreraptor also shared characteristics with an unusual 65-million-year-old fossil from Madagascar known as Rahonavis -- thought to have been a primitive, long-tailed bird.
By Guy Gugliotta
Tuesday, September 27, 2005
Wednesday, August 17, 2005
Genetics Links Whale to Two Different Oceans
For the first time ever, a genetic study has followed a single humpback whale from one ocean basin to another, adding to traditional notions of the migratory patterns of these majestic marine mammals in the process, according to researchers from the Wildlife Conservation Society (WCS), the American Museum of Natural History (AMNH), and New York University. In the most recent Royal Society’s Biology Letters, a male humpback whale that was first sighted in Madagascar’s Antongil Bay in 2000 was found in 2002 swimming off the coast of Loango National Park in Gabon—on the other side of the African continent.
“While the movement of whales from one ocean to another has always been a possibility, it’s quite difficult to track in the wild,” said WCS researcher Dr. Cristina Pomilla, lead author of the study. “This study demonstrates the ability of molecular technologies to confirm the movements of an individual whale between ocean basins.”
The study examined DNA samples extracted from skin biopsies collected from whales in the wintering grounds of both the Indian and South Atlantic Oceans for evidence of inter-oceanic exchange of individuals. Using a method of genetic capture-recapture of genotypes constructed of microsatellite markers, the researchers identified an individual whale sampled in Gabonese waters in 2002 that had been first seen (and sampled) with its mother in Madagascar waters in 2000. Pomilla and her colleague, Dr. Howard Rosenbaum of WCS and AMNH, suspect that the whale could have been a three- to four-year old juvenile at the time of the second encounter with researchers.
The only other documentation of individual humpback whales moving from one ocean basin to another dates back to when the species still was hunted commercially. Two whales that were marked off western Australia (in the Indian Ocean basin) were later killed off the coast of eastern Australian, in the Pacific Ocean.
The identification of individual whales moving between ocean basins will help inform a number of conservation activities relating to humpback whales, including how these populations are defined, studied and managed. Humpback whales were hunted commercially until the International Whaling Commission protected the species globally in 1966.
“These findings will help us improve our understanding of how populations of whales are connected, both genetically and even culturally, in the form of the haunting songs that this species is well-known for,” added Rosenbaum. “In particular, inter-oceanic migration data will help us to better evaluate the current international management procedures for humpback whales.”
Libraries
Science News Keywords
HUMPBACK WHALE GENETICS
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Available for logged-in reporters only
Description
For the first time ever, a genetic study has followed a single humpback whale from one ocean basin to another, adding to traditional notions of the migratory patterns of these majestic marine mammals in the process, according to researchers.
“While the movement of whales from one ocean to another has always been a possibility, it’s quite difficult to track in the wild,” said WCS researcher Dr. Cristina Pomilla, lead author of the study. “This study demonstrates the ability of molecular technologies to confirm the movements of an individual whale between ocean basins.”
The study examined DNA samples extracted from skin biopsies collected from whales in the wintering grounds of both the Indian and South Atlantic Oceans for evidence of inter-oceanic exchange of individuals. Using a method of genetic capture-recapture of genotypes constructed of microsatellite markers, the researchers identified an individual whale sampled in Gabonese waters in 2002 that had been first seen (and sampled) with its mother in Madagascar waters in 2000. Pomilla and her colleague, Dr. Howard Rosenbaum of WCS and AMNH, suspect that the whale could have been a three- to four-year old juvenile at the time of the second encounter with researchers.
The only other documentation of individual humpback whales moving from one ocean basin to another dates back to when the species still was hunted commercially. Two whales that were marked off western Australia (in the Indian Ocean basin) were later killed off the coast of eastern Australian, in the Pacific Ocean.
The identification of individual whales moving between ocean basins will help inform a number of conservation activities relating to humpback whales, including how these populations are defined, studied and managed. Humpback whales were hunted commercially until the International Whaling Commission protected the species globally in 1966.
“These findings will help us improve our understanding of how populations of whales are connected, both genetically and even culturally, in the form of the haunting songs that this species is well-known for,” added Rosenbaum. “In particular, inter-oceanic migration data will help us to better evaluate the current international management procedures for humpback whales.”
Libraries
Science News Keywords
HUMPBACK WHALE GENETICS
Contact Information
Available for logged-in reporters only
Description
For the first time ever, a genetic study has followed a single humpback whale from one ocean basin to another, adding to traditional notions of the migratory patterns of these majestic marine mammals in the process, according to researchers.
Monday, August 15, 2005
Mysteries of garlic are revealed
University of California scientists have determined garlic's active ingredients work the same in the same way as the chemicals in chili peppers and wasabi.
Researchers at the University of California-San Francisco's Department of Cellular and Molecular Pharmacology said garlic's pungent aroma and its effects on the body, such as dilating blood vessels, are due to a variety of sulfur-based chemicals, especially allicin.
Little is known about how those compounds produce their effects on a molecular level, but researchers David Julius and colleagues demonstrated garlic extracts, as well as purified allicin, excite a subset of sensory pain neurons from rats by activating a cell membrane channel called TRPA1. The excited neurons then release brain chemicals stimulating blood vessel dilation and inflammation in rats.
Interestingly, the scientists said, both capsaicin -- found in chili peppers -- and allyl isothiocyanate -- found in mustard plants -- also activate the TRP channel pathway, suggesting the different plant species have developed convergent strategies of chemical irritation.
The study appears in this week's online early edition of the Proceedings of the National Academy of Sciences.
Researchers at the University of California-San Francisco's Department of Cellular and Molecular Pharmacology said garlic's pungent aroma and its effects on the body, such as dilating blood vessels, are due to a variety of sulfur-based chemicals, especially allicin.
Little is known about how those compounds produce their effects on a molecular level, but researchers David Julius and colleagues demonstrated garlic extracts, as well as purified allicin, excite a subset of sensory pain neurons from rats by activating a cell membrane channel called TRPA1. The excited neurons then release brain chemicals stimulating blood vessel dilation and inflammation in rats.
Interestingly, the scientists said, both capsaicin -- found in chili peppers -- and allyl isothiocyanate -- found in mustard plants -- also activate the TRP channel pathway, suggesting the different plant species have developed convergent strategies of chemical irritation.
The study appears in this week's online early edition of the Proceedings of the National Academy of Sciences.
Tuesday, August 09, 2005
Before Watson and Crick
The first half of 20th-century science belonged to physics, with the general theory of relativity, quantum mechanics, and nuclear fission. The second half would belong to biology. In the post-war world, the secret of the gene—how hereditary characteristics pass from one generation to another—was the hottest topic in science.
For a number of physicists who had worked on the Manhattan Project to develop the atomic bomb, the post-war shift into biology was a stark exchange of the science of death for the science of life. But their conversion was as much intellectual as ideological. Biology was now where the action lay. The war had interrupted a line of investigation leading towards understanding the chemical basis of heredity.
Seeking the genetic messenger
That physical features are passed on by discrete units (later called genes) had been discovered in 1865 by the Austrian monk Gregor Mendel in his experiments with garden peas. Each gene determined a single characteristic, such as height or color, in the next generation of plant. By 1905 it had been learned that within living cells the genes are strung together like beads on the chromosomes, which copy themselves and separate. But how does the genetic information get from the old chromosome to the new?
Protein was the obvious candidate. By the 1920s it was thought that genes were made of protein. The other main ingredient in the chromosome is deoxyribonucleic acid, or DNA. DNA, a substance of high molecular weight, was identified in 1871 by a young Swiss scientist, Friedrich Miescher. (There is, in fact, a second kind of nucleic acid in the cell, called RNA, with a slightly different chemical composition.) The "D" in DNA stands for "deoxy"—a prefix often spelled as "des" in Rosalind's day, a usage now obsolete—which identifies it as the ribonucleic acid with one fewer hydroxyl group. But as RNA exists in cells mainly outside the nucleus, it was unlikely to be the genetic vehicle.
Protein was far more interesting to geneticists than DNA because there was a lot more of it and also because each protein molecule is a long chain of chemicals, of which 20 kinds occur in living things. DNA, in contrast, contains only four kinds of the repeating units called nucleotides. Hence it seemed too simple to carry the complex instructions required to specify the distinct form of each of the infinite variety of cells that constitute living matter.
In 1936, at the Rockefeller Institute on the Upper East Side of Manhattan, a microbiologist called Oswald Avery wondered aloud if the "transforming principle"—that is, the carrier of the genetic information from old chromosomes to new—might not be the nucleic acid, DNA. No one took much notice. DNA seemed just a boring binding agent for the protein in the cell.
During the pre-war years, in Britain, J.D. Bernal at Cambridge and William Astbury at Leeds, both crystallographers, began using X-rays to determine the structure of molecules in crystals. Astbury, interested in very large biological molecules, had taken hundreds of X-ray diffraction pictures of fibers prepared from DNA. From the diffraction patterns obtained, Astbury tried building a model of DNA. With metal plates and rods, he put together a Meccano-like model suggesting how DNA's components—bases, sugars, phosphates—might fit together. Astbury concluded—correctly, as it turned out—that the bases lay flat, stacked on each other like a pile of pennies spaced 3.4 Ångströms apart. [An Ångström equals one ten-billionth of a meter.] This "3.4 Å" was no gratuituous detail. Published with other measurements in an Astbury paper in Nature in 1938, it was to remain constant throughout all the attempts to solve DNA's structure that were to come.
Avery’s discovery has been called worth two Nobel Prizes, but he never got even one.
But Astbury made serious errors, his work was tentative, and he had no clear idea of the way forward. By the time of the Second World War, no one knew that genes were composed entirely of DNA.
The gene's genie
In 1943, Avery, at 67, was too old for military service. Still working at the Rockefeller Institute and building on an experiment with pneumococcus (bacteria that cause pneumonia) done by the English physician Frederick Griffith in 1928, he made a revolutionary discovery. He found that when DNA was transferred from a dead strain of pneumoccocus to a living strain, it brought with it the hereditary attributes of the donor.
Was the "transforming principle" so simple then—purely DNA? In science, where many grab for glory, there are some who thrust glory from them. Avery, a shy bachelor who wore a pince-nez, was one of those too modest for his own good. His discovery has been called worth two Nobel Prizes, but he never got even one—perhaps because, rather than rushing into print, he put his findings in a letter to his brother Roy, a medical bacteriologist at Vanderbilt University Medical School in Nashville. "I have not published anything about it—indeed have discussed it only with a few," he said, "because I am not yet convinced that we have (as yet) sufficient evidence."
A year later, however, Avery, with two colleagues, wrote out their research. In what became a classic paper, they described an intricate series of experiments using the two forms of pneumococcus, virulent and nonvirulent. When they freed a purified form of DNA from heat-killed virulent pneumococcus bacteria and injected it into a live, nonvirulent strain, they found that it produced a permanent heritable change in the DNA of the recipient cells. Thus the fact was established—at least for the readers of The Journal of Experimental Medicine—that the nucleic acid DNA and not the protein was the genetic message-carrier.
The essential mystery remained. How could a monotonous substance such as DNA, like an alphabet with only four letters, convey enough specific information to produce the enormous variety of living things, from daisies to dinosaurs? The answer must lie in the way the molecule was put together. Avery and his co-authors, Colin MacLeod and Maclyn McCarty, could say no more than that "nucleic acids must be regarded as possessing biological specificity the chemical basis of which is as yet undetermined."
Biophysics is born
In 1943, another scientist at one remove from the world conflict (because he had been offered a haven in neutral Ireland) gave a series of lectures in Dublin, called provocatively "What is Life?" An audience of 400 for every lecture suggested that his supposedly difficult subject was of great general interest.
Erwin Schrödinger, a Viennese, had shared the Nobel Prize in physics in 1933 for laying the foundations of wave mechanics. That same year he left Berlin, where he had been working, because, although not himself Jewish, he would not remain in Germany when persecution of the Jews became national policy. A long odyssey through Europe brought him, in 1940, to Dublin at the invitation of Eamon de Valera, Ireland's premier. De Valera had been a mathematician before he became a revolutionary, then a politician; in 1940 he set up the Dublin Institute of Advanced Studies. Schrödinger found Ireland "paradise," not least because it allowed him the detachment to think about a very big question.
In his Dublin lectures, Schrödinger addressed what puzzled many students—why biology was treated as a subject completely separate from physics and chemistry: frogs, fruit flies, and cells on one side, atoms and molecules, electricity and magnetism, on the other. The time had come, Schrödinger declared from his Irish platform, to think of living organisms in terms of their molecular and atomic structure. There was no great divide between the living and nonliving; they all obey the same laws of physics and chemistry.
He put a physicist's question to biology. If entropy is (according to the second law of thermodynamics) things falling apart, the natural disintegration of order into disorder, why don't genes decay? Why are they instead passed intact from generation to generation?
What Is Life? was the Uncle Tom’s Cabin of biology—a small book that started a revolution.
He gave his own answer. "Life" is matter that is doing something. The technical term is metabolism—"eating, drinking, breathing, assimilating, replicating, avoiding entropy." To Schrödinger, life could be defined as "negative entropy"—something not falling into chaos and approaching "the dangerous state of maximum entropy, which is death." Genes preserve their structure because the chromosome that carries them is an irregular crystal. The arrangement of units within the crystal constitutes the hereditary code.
The lectures were published as a book the following year, ready for physicists to read as the war ended and they looked for new frontiers to explore. To the molecular biologist and scientific historian Gunther Stent of the University of California at Berkeley, What Is Life? was the Uncle Tom's Cabin of biology—a small book that started a revolution. For post-war physicists, suffering from professional malaise, "When one of the inventors of quantum mechanics [could] ask 'What is life?,'" Stent declared, "they were confronted with a fundamental problem worthy of their mettle." Biological problems could now be tackled with their own language, physics.
Research into the new field of biophysics inched forward in the late 1940s. In 1949 another Austrian refugee scientist, Erwin Chargaff, working at the Columbia College of Physicians and Surgeons in New York, was one of the very few who took Avery's results to heart and changed his research program in consequence. He analyzed the proportions of the four bases of DNA and found a curious correspondence. The numbers of molecules present of the two bases, adenine and guanine, called purines, were always equal to the total amount of thymine and cytosine, the other two bases, called pyrimidines. This neat ratio, found in all forms of DNA, cried out for explanation, but Chargaff could not think what it might be.
That is where things stood when Rosalind Franklin arrived at King's College London on 5 January 1951. Leaving coal research to work on DNA, moving from the crystal structure of inanimate substances to that of biological molecules, she had crossed the border between nonliving and living. Coal does not make more coal, but genes make more genes.
by Brenda Maddox
For a number of physicists who had worked on the Manhattan Project to develop the atomic bomb, the post-war shift into biology was a stark exchange of the science of death for the science of life. But their conversion was as much intellectual as ideological. Biology was now where the action lay. The war had interrupted a line of investigation leading towards understanding the chemical basis of heredity.
That physical features are passed on by discrete units (later called genes) had been discovered in 1865 by the Austrian monk Gregor Mendel in his experiments with garden peas. Each gene determined a single characteristic, such as height or color, in the next generation of plant. By 1905 it had been learned that within living cells the genes are strung together like beads on the chromosomes, which copy themselves and separate. But how does the genetic information get from the old chromosome to the new?
Protein was the obvious candidate. By the 1920s it was thought that genes were made of protein. The other main ingredient in the chromosome is deoxyribonucleic acid, or DNA. DNA, a substance of high molecular weight, was identified in 1871 by a young Swiss scientist, Friedrich Miescher. (There is, in fact, a second kind of nucleic acid in the cell, called RNA, with a slightly different chemical composition.) The "D" in DNA stands for "deoxy"—a prefix often spelled as "des" in Rosalind's day, a usage now obsolete—which identifies it as the ribonucleic acid with one fewer hydroxyl group. But as RNA exists in cells mainly outside the nucleus, it was unlikely to be the genetic vehicle.
Protein was far more interesting to geneticists than DNA because there was a lot more of it and also because each protein molecule is a long chain of chemicals, of which 20 kinds occur in living things. DNA, in contrast, contains only four kinds of the repeating units called nucleotides. Hence it seemed too simple to carry the complex instructions required to specify the distinct form of each of the infinite variety of cells that constitute living matter.
In 1936, at the Rockefeller Institute on the Upper East Side of Manhattan, a microbiologist called Oswald Avery wondered aloud if the "transforming principle"—that is, the carrier of the genetic information from old chromosomes to new—might not be the nucleic acid, DNA. No one took much notice. DNA seemed just a boring binding agent for the protein in the cell.
During the pre-war years, in Britain, J.D. Bernal at Cambridge and William Astbury at Leeds, both crystallographers, began using X-rays to determine the structure of molecules in crystals. Astbury, interested in very large biological molecules, had taken hundreds of X-ray diffraction pictures of fibers prepared from DNA. From the diffraction patterns obtained, Astbury tried building a model of DNA. With metal plates and rods, he put together a Meccano-like model suggesting how DNA's components—bases, sugars, phosphates—might fit together. Astbury concluded—correctly, as it turned out—that the bases lay flat, stacked on each other like a pile of pennies spaced 3.4 Ångströms apart. [An Ångström equals one ten-billionth of a meter.] This "3.4 Å" was no gratuituous detail. Published with other measurements in an Astbury paper in Nature in 1938, it was to remain constant throughout all the attempts to solve DNA's structure that were to come.
Avery’s discovery has been called worth two Nobel Prizes, but he never got even one.
But Astbury made serious errors, his work was tentative, and he had no clear idea of the way forward. By the time of the Second World War, no one knew that genes were composed entirely of DNA.
In 1943, Avery, at 67, was too old for military service. Still working at the Rockefeller Institute and building on an experiment with pneumococcus (bacteria that cause pneumonia) done by the English physician Frederick Griffith in 1928, he made a revolutionary discovery. He found that when DNA was transferred from a dead strain of pneumoccocus to a living strain, it brought with it the hereditary attributes of the donor.
Was the "transforming principle" so simple then—purely DNA? In science, where many grab for glory, there are some who thrust glory from them. Avery, a shy bachelor who wore a pince-nez, was one of those too modest for his own good. His discovery has been called worth two Nobel Prizes, but he never got even one—perhaps because, rather than rushing into print, he put his findings in a letter to his brother Roy, a medical bacteriologist at Vanderbilt University Medical School in Nashville. "I have not published anything about it—indeed have discussed it only with a few," he said, "because I am not yet convinced that we have (as yet) sufficient evidence."
A year later, however, Avery, with two colleagues, wrote out their research. In what became a classic paper, they described an intricate series of experiments using the two forms of pneumococcus, virulent and nonvirulent. When they freed a purified form of DNA from heat-killed virulent pneumococcus bacteria and injected it into a live, nonvirulent strain, they found that it produced a permanent heritable change in the DNA of the recipient cells. Thus the fact was established—at least for the readers of The Journal of Experimental Medicine—that the nucleic acid DNA and not the protein was the genetic message-carrier.
The essential mystery remained. How could a monotonous substance such as DNA, like an alphabet with only four letters, convey enough specific information to produce the enormous variety of living things, from daisies to dinosaurs? The answer must lie in the way the molecule was put together. Avery and his co-authors, Colin MacLeod and Maclyn McCarty, could say no more than that "nucleic acids must be regarded as possessing biological specificity the chemical basis of which is as yet undetermined."
In 1943, another scientist at one remove from the world conflict (because he had been offered a haven in neutral Ireland) gave a series of lectures in Dublin, called provocatively "What is Life?" An audience of 400 for every lecture suggested that his supposedly difficult subject was of great general interest.
Erwin Schrödinger, a Viennese, had shared the Nobel Prize in physics in 1933 for laying the foundations of wave mechanics. That same year he left Berlin, where he had been working, because, although not himself Jewish, he would not remain in Germany when persecution of the Jews became national policy. A long odyssey through Europe brought him, in 1940, to Dublin at the invitation of Eamon de Valera, Ireland's premier. De Valera had been a mathematician before he became a revolutionary, then a politician; in 1940 he set up the Dublin Institute of Advanced Studies. Schrödinger found Ireland "paradise," not least because it allowed him the detachment to think about a very big question.
In his Dublin lectures, Schrödinger addressed what puzzled many students—why biology was treated as a subject completely separate from physics and chemistry: frogs, fruit flies, and cells on one side, atoms and molecules, electricity and magnetism, on the other. The time had come, Schrödinger declared from his Irish platform, to think of living organisms in terms of their molecular and atomic structure. There was no great divide between the living and nonliving; they all obey the same laws of physics and chemistry.
He put a physicist's question to biology. If entropy is (according to the second law of thermodynamics) things falling apart, the natural disintegration of order into disorder, why don't genes decay? Why are they instead passed intact from generation to generation?
He gave his own answer. "Life" is matter that is doing something. The technical term is metabolism—"eating, drinking, breathing, assimilating, replicating, avoiding entropy." To Schrödinger, life could be defined as "negative entropy"—something not falling into chaos and approaching "the dangerous state of maximum entropy, which is death." Genes preserve their structure because the chromosome that carries them is an irregular crystal. The arrangement of units within the crystal constitutes the hereditary code.
The lectures were published as a book the following year, ready for physicists to read as the war ended and they looked for new frontiers to explore. To the molecular biologist and scientific historian Gunther Stent of the University of California at Berkeley, What Is Life? was the Uncle Tom's Cabin of biology—a small book that started a revolution. For post-war physicists, suffering from professional malaise, "When one of the inventors of quantum mechanics [could] ask 'What is life?,'" Stent declared, "they were confronted with a fundamental problem worthy of their mettle." Biological problems could now be tackled with their own language, physics.
Research into the new field of biophysics inched forward in the late 1940s. In 1949 another Austrian refugee scientist, Erwin Chargaff, working at the Columbia College of Physicians and Surgeons in New York, was one of the very few who took Avery's results to heart and changed his research program in consequence. He analyzed the proportions of the four bases of DNA and found a curious correspondence. The numbers of molecules present of the two bases, adenine and guanine, called purines, were always equal to the total amount of thymine and cytosine, the other two bases, called pyrimidines. This neat ratio, found in all forms of DNA, cried out for explanation, but Chargaff could not think what it might be.
That is where things stood when Rosalind Franklin arrived at King's College London on 5 January 1951. Leaving coal research to work on DNA, moving from the crystal structure of inanimate substances to that of biological molecules, she had crossed the border between nonliving and living. Coal does not make more coal, but genes make more genes.
by Brenda Maddox
Researchers Pinpoint Source of Poison Frogs' Deadly Defenses
The poison frogs of Central and South America are as deadly as they are beautiful, thanks to chemicals called alkaloids that they secrete through their skin. Indeed, the venom from a single golden poison frog, for example, can kill 10 humans. Now researchers have unlocked the secrets of their counterparts in Madagascar and found that they employ the same method of acquiring thier toxins: through careful food consumption.
Studies of these frogs in the Neotropics indicated that a diet rich in ants provided the alkaloids, but whether the same held true for Malagasy populations was unknown. Now Valerie Clark of Columbia University and the American Museum of Natural History in New York City and her colleagues have resolved the mystery. By analyzing three poison frog species from Madagascar and their potential food sources, the team found that ants--including one species not previously known to impart poisonous alkaloids--provide the Malagasy frogs with the chemicals that comprise their toxic secretions. Three of the chemicals are unique to creature living in Madagascar.
Because neither the frogs nor the ants from the two regions are closely related, the results indicate that the ability to utilize ants both as food and as the source of a defense weapon against danger developed independently in two diverse regions of the world. In a paper published online this week by the Proceedings of the National Academy of Sciences, the researchers posit that the earlier convergent evolution of ants containing the proper chemicals may have been the critical prerequisite for the development of poison frogs in distant locales. --
Sarah Graham
Studies of these frogs in the Neotropics indicated that a diet rich in ants provided the alkaloids, but whether the same held true for Malagasy populations was unknown. Now Valerie Clark of Columbia University and the American Museum of Natural History in New York City and her colleagues have resolved the mystery. By analyzing three poison frog species from Madagascar and their potential food sources, the team found that ants--including one species not previously known to impart poisonous alkaloids--provide the Malagasy frogs with the chemicals that comprise their toxic secretions. Three of the chemicals are unique to creature living in Madagascar.
Because neither the frogs nor the ants from the two regions are closely related, the results indicate that the ability to utilize ants both as food and as the source of a defense weapon against danger developed independently in two diverse regions of the world. In a paper published online this week by the Proceedings of the National Academy of Sciences, the researchers posit that the earlier convergent evolution of ants containing the proper chemicals may have been the critical prerequisite for the development of poison frogs in distant locales. --
Sarah Graham
Monday, August 01, 2005
Get the KAT Purring along and Local Science will win
Astronomy: South Africa's bid to become a leader in the development of international astronomy and space projects will take a step forward with the construction of a new telescope to be built in the Karoo.
The Karoo Array Telescope (KAT) could ultimately be a component of the euro 1bn Square Kilometre Array (SKA), a global radio telescope which will span continents and probe the secrets of space . Argentina, Australia, China and SA are participants in the SKA project but are also bidding against each other to become the main site for the project. Final bid documents are due for submission by December but the winner is expected to be announced only in mid-2007.
Though SA has many geographic and weather advantages over its rivals, high telecommunications costs and uncertain regulation could well scupper its bid.
The KAT is emerging as highly strategic in SA's space science agenda. It is integral to the SKA bid and, as part of the growing network of telescopes in Southern Africa (which include those in Sutherland, Namibia and Hartebeesthoek), it will encourage scientific research in this region.
"KAT will enable us to contribute to the study of the evolution of the universe," says SKA project manager Bernie Fanaroff. "It will not be able to see as far back into the history of the universe as the SKA will allow, but we should be able to map the galaxies as they were billions of years ago, when the universe and galaxies were still quite young."
KAT will also serve as a showcase for SA technologies that are expected to be critical to the SKA project. "If we get the technology right for KAT, our participating universities and industry have a good chance of being major suppliers for the whole project, even if SA does not win the bid to host the array," says Fanaroff.
In addition, the advanced technologies that will result from the KAT project will have a positive impact on SA's ability to compete in the global high-technology marketplace.
The KAT will be an array made up of 20 dishes, each 15 m in diameter, spread out over a kilometre in the Karoo.
The project team is in the research, development and costing phase and requests for information are being sent to local, Russian, German and Chinese companies in the scientific software, digital signal processing and structural steel industries, among others.
The KAT project is also benefiting from collaboration with the universities of Oxford, Cambridge, Manchester and the University of California at Berkeley as well as the Australian National Telescope Facility and the Astronomical Institute in the Netherlands. "We have benefited from their experience and learning, which has allowed us to move quickly into cutting-edge development," says Fanaroff.
For instance, SA is collaborating on new focal-plane phased arrays that will allow the KAT to generate up to 40 beams from each dish. "It is equivalent to looking in 40 different directions at the same time ."
Though SA is competing with Australia to host the core of the SKA, the two countries are collaborating over the design of the smaller demonstrator telescopes. Australia is building its own KAT, named the Extended New Technology Demonstrator, to a different design. Both telescopes will be built by 2009, an extraordinarily tight time-frame.
These telescopes don't come cheap. The Southern African Large Telescope in Sutherland, the largest telescope in the southern hemisphere, cost government and other investors about US$30m.
Meanwhile, much work remains for the SKA bid team.
SA has completed its studies into the troposphere - the lowest layer of the atmosphere, where most clouds and water vapour are located. In the dry Northern Cape, there is not enough water in the atmosphere to absorb and disturb radio waves at high frequencies.
And the ionosphere - the region of charged particles in the upper atmosphere which can disturb radio waves occurring at lower frequencies - is stable above SA.
Outstanding issues include the technology and costing details for the data network.
The SKA - which is really a supercomputer with eyes into the heavens - will produce and transmit more data than the rest of SA combined. "We will need a network capable of speeds of 4 Tbit/s from the core [8,4m times faster than Telkom's fastest ADSL broadband connection] and 100 Gbit/s from the outlying areas [200 000 times faster than Telkom's best ]," says Fanaroff.
Exactly how this will be achieved has not been decided. What is certain is that cost will count. Data transmission tariffs will be one of the biggest costs in the SKA. An interesting example is the European Union's Géant network. In this case a consortium of partners built a network backbone capable of gigabit speeds to meet the research needs of 26 national research and education networks across Europe.
Today the network is connected to countries around the world - including, in the near future, SA. "Part of the capacity in some of the countries is used by commercial customers, which subsidise the costs of the research institutions," says Fanaroff.
Another outstanding worry is that of preserving radio quietness around the core of the SKA as well as the many small antennas that will make up the receiving surface of the telescope.
The SKA, if it is built in Southern Africa, will have its core in the Northern Cape and stations in Botswana, Madagascar, Mauritius, Mozambique, Namibia, Kenya and Ghana.
In each of these countries the antennas will have to be sheltered from radio interference. "The SKA uses frequencies that extend beyond the spectrum explicitly reserved by the International Telecommunications Union for radio astronomy."
The SKA project team has been in discussions with SA's own regulator, Icasa, as well as those of the neighbouring countries. The Australian team recently made a significant move when its regulator issued a moratorium on new transmissions in the zone around their proposed site.
SA is still talking to Icasa to find ways to create a radio quiet zone around the core of the telescope, which is the most sensitive to radio interference.
In April the international SKA site spectrum monitoring team arrived in SA to conduct radio frequency interference studies at the core site . These confirmed the SA site as a very quiet area for radio interference. The team must now study China, Australia and Argentina.
As the December deadline looms, the KAT project team will continue working on new prototypes for digital receiver technology, digital beam-formers and low-cost designs for the telescope dishes.
SA's increasingly visible prowess in the space science industry has also resulted in a number of foreign institutions expressing an interest in building their own infrastructure here.
By Sasha Planting
SA is making progress in its bid for a euro 1bn global space project
The Karoo Array Telescope (KAT) could ultimately be a component of the euro 1bn Square Kilometre Array (SKA), a global radio telescope which will span continents and probe the secrets of space . Argentina, Australia, China and SA are participants in the SKA project but are also bidding against each other to become the main site for the project. Final bid documents are due for submission by December but the winner is expected to be announced only in mid-2007.
Though SA has many geographic and weather advantages over its rivals, high telecommunications costs and uncertain regulation could well scupper its bid.
The KAT is emerging as highly strategic in SA's space science agenda. It is integral to the SKA bid and, as part of the growing network of telescopes in Southern Africa (which include those in Sutherland, Namibia and Hartebeesthoek), it will encourage scientific research in this region.
"KAT will enable us to contribute to the study of the evolution of the universe," says SKA project manager Bernie Fanaroff. "It will not be able to see as far back into the history of the universe as the SKA will allow, but we should be able to map the galaxies as they were billions of years ago, when the universe and galaxies were still quite young."
KAT will also serve as a showcase for SA technologies that are expected to be critical to the SKA project. "If we get the technology right for KAT, our participating universities and industry have a good chance of being major suppliers for the whole project, even if SA does not win the bid to host the array," says Fanaroff.
In addition, the advanced technologies that will result from the KAT project will have a positive impact on SA's ability to compete in the global high-technology marketplace.
The KAT will be an array made up of 20 dishes, each 15 m in diameter, spread out over a kilometre in the Karoo.
The project team is in the research, development and costing phase and requests for information are being sent to local, Russian, German and Chinese companies in the scientific software, digital signal processing and structural steel industries, among others.
The KAT project is also benefiting from collaboration with the universities of Oxford, Cambridge, Manchester and the University of California at Berkeley as well as the Australian National Telescope Facility and the Astronomical Institute in the Netherlands. "We have benefited from their experience and learning, which has allowed us to move quickly into cutting-edge development," says Fanaroff.
For instance, SA is collaborating on new focal-plane phased arrays that will allow the KAT to generate up to 40 beams from each dish. "It is equivalent to looking in 40 different directions at the same time ."
Though SA is competing with Australia to host the core of the SKA, the two countries are collaborating over the design of the smaller demonstrator telescopes. Australia is building its own KAT, named the Extended New Technology Demonstrator, to a different design. Both telescopes will be built by 2009, an extraordinarily tight time-frame.
These telescopes don't come cheap. The Southern African Large Telescope in Sutherland, the largest telescope in the southern hemisphere, cost government and other investors about US$30m.
Meanwhile, much work remains for the SKA bid team.
SA has completed its studies into the troposphere - the lowest layer of the atmosphere, where most clouds and water vapour are located. In the dry Northern Cape, there is not enough water in the atmosphere to absorb and disturb radio waves at high frequencies.
And the ionosphere - the region of charged particles in the upper atmosphere which can disturb radio waves occurring at lower frequencies - is stable above SA.
Outstanding issues include the technology and costing details for the data network.
The SKA - which is really a supercomputer with eyes into the heavens - will produce and transmit more data than the rest of SA combined. "We will need a network capable of speeds of 4 Tbit/s from the core [8,4m times faster than Telkom's fastest ADSL broadband connection] and 100 Gbit/s from the outlying areas [200 000 times faster than Telkom's best ]," says Fanaroff.
Exactly how this will be achieved has not been decided. What is certain is that cost will count. Data transmission tariffs will be one of the biggest costs in the SKA. An interesting example is the European Union's Géant network. In this case a consortium of partners built a network backbone capable of gigabit speeds to meet the research needs of 26 national research and education networks across Europe.
Today the network is connected to countries around the world - including, in the near future, SA. "Part of the capacity in some of the countries is used by commercial customers, which subsidise the costs of the research institutions," says Fanaroff.
Another outstanding worry is that of preserving radio quietness around the core of the SKA as well as the many small antennas that will make up the receiving surface of the telescope.
The SKA, if it is built in Southern Africa, will have its core in the Northern Cape and stations in Botswana, Madagascar, Mauritius, Mozambique, Namibia, Kenya and Ghana.
In each of these countries the antennas will have to be sheltered from radio interference. "The SKA uses frequencies that extend beyond the spectrum explicitly reserved by the International Telecommunications Union for radio astronomy."
The SKA project team has been in discussions with SA's own regulator, Icasa, as well as those of the neighbouring countries. The Australian team recently made a significant move when its regulator issued a moratorium on new transmissions in the zone around their proposed site.
SA is still talking to Icasa to find ways to create a radio quiet zone around the core of the telescope, which is the most sensitive to radio interference.
In April the international SKA site spectrum monitoring team arrived in SA to conduct radio frequency interference studies at the core site . These confirmed the SA site as a very quiet area for radio interference. The team must now study China, Australia and Argentina.
As the December deadline looms, the KAT project team will continue working on new prototypes for digital receiver technology, digital beam-formers and low-cost designs for the telescope dishes.
SA's increasingly visible prowess in the space science industry has also resulted in a number of foreign institutions expressing an interest in building their own infrastructure here.
By Sasha Planting
SA is making progress in its bid for a euro 1bn global space project
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