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.”
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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.
Wednesday, August 17, 2005
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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