Most of the Earth's listed active volcanoes are located at the borders between two tectonic plates, where upsurge of magma from the mantle is facilitated. When these magmatic uprisings occur at a subduction zone, where one tectonic plate plunges under another, they give rise to volcanic massifs such as the Andes cordillera. Other volcanic chains are formed along oceanic ridges, submarine regions of ocean-floor extension. However, some volcanoes are governed by a completely different mechanism: intraplate volcanism. As their name suggests, these volcanic constructions appear in the very centre of tectonic plates.
Scientists now know that some of them, such as the Hawaii-Emperor archipelago or Reunion Island, result from magmatic upsurges generated at the boundary between the Earth's core and mantle situated 2 900 km deep. Others, such as those of the central Pacific, display different characteristics. They are anomalous, in their simultaneously high number, unusually high concentration and short life-span and prompt scientists to look for hypotheses other than a deep-mantle plume to explain the causes of intraplate volcanism.
Science & Technology
The first large-scale, high-resolution study of human genetic recombination has found remarkably high levels of individual variation in genetic exchange, the process by which parents pass on a mosaic-like mixture of their genes.
In an article appearing February 1, 2008, in Science Express, the online version of Science, researchers from the University of Chicago locate nearly 25,000 recombination events that occurred in the transmission of the parental genomes to 364 offspring. The high-resolution of their maps allows them to provide the precise location of where these genetic exchanges occur, and to assess the differences in recombination rates between individuals.
"Genetic recombination is a fundamental process, at the core of reproduction and evolution," said study author Graham Coop, PhD, post-doctoral fellow in the Department of Human Genetics at the University of Chicago, "yet we know very little about where it occurs or why there is so much variation among individuals in this important process."
In an article appearing February 1, 2008, in Science Express, the online version of Science, researchers from the University of Chicago locate nearly 25,000 recombination events that occurred in the transmission of the parental genomes to 364 offspring. The high-resolution of their maps allows them to provide the precise location of where these genetic exchanges occur, and to assess the differences in recombination rates between individuals.
"Genetic recombination is a fundamental process, at the core of reproduction and evolution," said study author Graham Coop, PhD, post-doctoral fellow in the Department of Human Genetics at the University of Chicago, "yet we know very little about where it occurs or why there is so much variation among individuals in this important process."
Frank Sinatra, Stephen Hawking, Marie Curie and Stephen Fry all owe their blue eyes to a genetic mutation that likely occurred between 6,000 and 10,000 years ago, researchers say. Scientists believe they have tracked down the cause of the eye colour of all blue-eyed humans on the planet today.
"Originally, we all had brown eyes", said Prof Hans Eiberg from the University of Copenhagen, who led the team.
Blue eye colour most likely originated from the near east area or northwest part of the Black Sea region, where the great agriculture migration to the northern part of Europe took place in the Neolithic periods about six - 10,000 years ago.
"Originally, we all had brown eyes", said Prof Hans Eiberg from the University of Copenhagen, who led the team.
Blue eye colour most likely originated from the near east area or northwest part of the Black Sea region, where the great agriculture migration to the northern part of Europe took place in the Neolithic periods about six - 10,000 years ago.
Washington - The first pictures from the unseen side of Mercury reveal the wrinkles of a shrinking, aging planet with scars from volcanic eruptions and a birthmark shaped like a spider.
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| ©AP Photo/NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington |
| This image provided by NASA shows: The Spider Radial Troughs within Caloris. The Narrow Angle Camera of the Mercury Dual Imaging System (MDIS) on the MESSENGER spacecraft obtained high-resolution images of the floor of the Caloris basin on January 14, 2008. Near the center of the basin, an area unseen by Mariner 10, this remarkable feature nicknamed the spider by the science team was revealed. A set of troughs radiates outward in a geometry unlike anything seen by Mariner 10. The radial troughs are interpreted to be the result of extension (breaking apart) of the floor materials that filled the Caloris basin after its formation. Other troughs near the center form a polygonal pattern. This type of polygonal pattern of troughs is also seen along the interior margin of the Caloris basin. An impact crater appears to be centered on the spider. The straight-line segments of the crater walls may have been influenced by preexisting extensional troughs, but some of the troughs may have formed at the time that the crater was excavated. |
It may sound like science fiction, but it's only a matter of time before the world's militaries learn to wield the planet itself as a weapon.
Preventing global warming from becoming a planetary catastrophe may take something even more drastic than renewable energy, superefficient urban design, and global carbon taxes. Such innovations remain critical, and yet disruptions to the Earth's climate could overwhelm these relatively slow, incremental changes in how we live. As reports of faster-than-expected climate changes mount, a growing number of experts worry that we might ultimately be forced to try something quite radical: geoengineering.
Geoengineering involves humans making intentional, large-scale modifications to the Earth's geophysical systems in order to change the environment. These can include sequestering atmospheric carbon dioxide in the oceans, changing the reflectivity of the Earth's surface, and pumping particles into the stratosphere to block a fraction of incoming sunlight. Many of these proposals mimic natural events, so we know that - in principle - they can work, although there is insufficient understanding of their potential side effects. Unsurprisingly, geoengineering is highly controversial, and even proponents view it as a "Hail Mary" pass, to be considered only after all other options have failed.
Preventing global warming from becoming a planetary catastrophe may take something even more drastic than renewable energy, superefficient urban design, and global carbon taxes. Such innovations remain critical, and yet disruptions to the Earth's climate could overwhelm these relatively slow, incremental changes in how we live. As reports of faster-than-expected climate changes mount, a growing number of experts worry that we might ultimately be forced to try something quite radical: geoengineering.
Geoengineering involves humans making intentional, large-scale modifications to the Earth's geophysical systems in order to change the environment. These can include sequestering atmospheric carbon dioxide in the oceans, changing the reflectivity of the Earth's surface, and pumping particles into the stratosphere to block a fraction of incoming sunlight. Many of these proposals mimic natural events, so we know that - in principle - they can work, although there is insufficient understanding of their potential side effects. Unsurprisingly, geoengineering is highly controversial, and even proponents view it as a "Hail Mary" pass, to be considered only after all other options have failed.
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| ©NASA |
If there were a portal linking us to a parallel universe or some other region of space, how would we spot it? One suggestion is that it will give itself away by the curious way it bends light.
The existence of wormholes linking different regions of space was suggested in 1916 by the Austrian physicist Ludwig Flamm as a possible solution to equations of general relativity, which Einstein had published that year. They have since become accepted as a natural consequence of general relativity, which predicts that matter entering one end of a wormhole would instantly emerge somewhere else, so long as the wormhole is somehow propped open.
Though no direct evidence for wormholes has been observed, this could be because they are disguised as black holes. Now Alexander Shatskiy of the Lebedev Physical Institute in Moscow, Russia, is suggesting a possible way to tell the two kinds of object apart. His idea assumes the existence of a bizarre substance called "phantom matter", which has been proposed to explain how wormholes might stay open. Phantom matter has negative energy and negative mass, so it creates a repulsive effect that prevents the wormhole closing.
The existence of wormholes linking different regions of space was suggested in 1916 by the Austrian physicist Ludwig Flamm as a possible solution to equations of general relativity, which Einstein had published that year. They have since become accepted as a natural consequence of general relativity, which predicts that matter entering one end of a wormhole would instantly emerge somewhere else, so long as the wormhole is somehow propped open.
Though no direct evidence for wormholes has been observed, this could be because they are disguised as black holes. Now Alexander Shatskiy of the Lebedev Physical Institute in Moscow, Russia, is suggesting a possible way to tell the two kinds of object apart. His idea assumes the existence of a bizarre substance called "phantom matter", which has been proposed to explain how wormholes might stay open. Phantom matter has negative energy and negative mass, so it creates a repulsive effect that prevents the wormhole closing.
The planet Mercury's magnetic field appears to be strong enough to fend off the harsh solar wind from most of its surface, according to data gathered in part by a University of Michigan instrument onboard NASA's MESSENGER spacecraft.
U-M's Fast Imaging Plasma Spectrometer (FIPS) on Jan. 14 took the first direct measurements of Mercury's magnetosphere to determine how the planet interacts with the space environment and the Sun.
The solar wind, a stream of charged particles, fills the entire solar system. It interacts with all planets, but bears down on Mercury, 2/3 closer than the Earth to the Sun.
U-M's Fast Imaging Plasma Spectrometer (FIPS) on Jan. 14 took the first direct measurements of Mercury's magnetosphere to determine how the planet interacts with the space environment and the Sun.
The solar wind, a stream of charged particles, fills the entire solar system. It interacts with all planets, but bears down on Mercury, 2/3 closer than the Earth to the Sun.
DNA is the blueprint of all life, giving instruction and function to organisms ranging from simple one-celled bacteria to complex human beings. Now Northwestern University researchers report they have used DNA as the blueprint, contractor and construction worker to build a three-dimensional structure out of gold, a lifeless material.
Using just one kind of nanoparticle (gold) the researchers built two common but very different crystalline structures by merely changing one thing -- the strands of synthesized DNA attached to the tiny gold spheres. A different DNA sequence in the strand resulted in the formation of a different crystal.
The technique, to be published Jan. 31 as the cover story in the journal Nature and reflecting more than a decade of work, is a major and fundamental step toward building functional "designer" materials using programmable self-assembly. This "bottom-up" approach will allow scientists to take inorganic materials and build structures with specific properties for a given application, such as therapeutics, biodiagnostics, optics, electronics or catalysis.
Using just one kind of nanoparticle (gold) the researchers built two common but very different crystalline structures by merely changing one thing -- the strands of synthesized DNA attached to the tiny gold spheres. A different DNA sequence in the strand resulted in the formation of a different crystal.
The technique, to be published Jan. 31 as the cover story in the journal Nature and reflecting more than a decade of work, is a major and fundamental step toward building functional "designer" materials using programmable self-assembly. This "bottom-up" approach will allow scientists to take inorganic materials and build structures with specific properties for a given application, such as therapeutics, biodiagnostics, optics, electronics or catalysis.
Boosted by physical and mental exercise, neural stem cells continue to sprout new neurons throughout life, but the exact function of these newcomers has been the topic of much debate. Removing a genetic master switch that maintains neural stem cells in their proliferative state finally gave researchers at the Salk Institute for Biological Studies some definitive answers.
Without adult neurogenesis - literally the "birth of neurons" - genetically engineered mice turned into "slow learners" that had trouble navigating a water maze and remembering the location of a submerged platform, the Salk investigators report in the Jan. 30 Advance Online Edition of Nature. The findings suggest that, one day, researchers might be able to stimulate neurogenesis with orally active drugs to influence memory function, the researchers say.
Without adult neurogenesis - literally the "birth of neurons" - genetically engineered mice turned into "slow learners" that had trouble navigating a water maze and remembering the location of a submerged platform, the Salk investigators report in the Jan. 30 Advance Online Edition of Nature. The findings suggest that, one day, researchers might be able to stimulate neurogenesis with orally active drugs to influence memory function, the researchers say.
New research shows that people with blue eyes have a single, common ancestor. A team at the University of Copenhagen have tracked down a genetic mutation which took place 6-10,000 years ago and is the cause of the eye colour of all blue-eyed humans alive on the planet today.
What is the genetic mutation
"Originally, we all had brown eyes", said Professor Eiberg from the Department of Cellular and Molecular Medicine. "But a genetic mutation affecting the OCA2 gene in our chromosomes resulted in the creation of a "switch", which literally "turned off" the ability to produce brown eyes". The OCA2 gene codes for the so-called P protein, which is involved in the production of melanin, the pigment that gives colour to our hair, eyes and skin. The "switch", which is located in the gene adjacent to OCA2 does not, however, turn off the gene entirely, but rather limits its action to reducing the production of melanin in the iris - effectively "diluting" brown eyes to blue. The switch's effect on OCA2 is very specific therefore. If the OCA2 gene had been completely destroyed or turned off, human beings would be without melanin in their hair, eyes or skin colour - a condition known as albinism.
What is the genetic mutation
"Originally, we all had brown eyes", said Professor Eiberg from the Department of Cellular and Molecular Medicine. "But a genetic mutation affecting the OCA2 gene in our chromosomes resulted in the creation of a "switch", which literally "turned off" the ability to produce brown eyes". The OCA2 gene codes for the so-called P protein, which is involved in the production of melanin, the pigment that gives colour to our hair, eyes and skin. The "switch", which is located in the gene adjacent to OCA2 does not, however, turn off the gene entirely, but rather limits its action to reducing the production of melanin in the iris - effectively "diluting" brown eyes to blue. The switch's effect on OCA2 is very specific therefore. If the OCA2 gene had been completely destroyed or turned off, human beings would be without melanin in their hair, eyes or skin colour - a condition known as albinism.
Comment: The prospect of geoengineering is far more worrying when one considers the psychopathic destructively short-sighted and self-interested nature of those in power who would direct such measures; and also the massive extent of the misconceptions and falsehoods that currently masquerade as scientific knowledge of the planet we inhabit - a lack of objectivity which could cause such measures to fail catastrophically.