MANILA, Philippines ? The Philippine military says communist guerrillas killed about 100 government troops and police and waged 447 attacks last year despite a continuing decline in their decades-long insurgency.
Military spokesman Col. Arnulfo Burgos said Sunday that the attacks by New People's Army guerrillas included 31 assaults on mining firms, banana plantations and other businesses. He said they earned nearly $7 million (300 million pesos) from extortion in 2011.
Burgos said the rebels' reliance on extortion from businesses and even poor villagers reflects a decline in their support from communities.
The Maoist rebels did not immediately comment, but have disputed such military claims in the past as propaganda amid escalating rebel attacks.
MacGregor Campbell, contributor If four vortices were let loose in a cup of melted ice cream and chocolate sauce, what would it look like? In this simulation, mathematical artist, Jos Leys illustrates the result by imagining that the two are ideal fluids, meaning that they have no viscosity and slide past each other with no resistance.
The vortices quickly stir things up, creating swirls reminiscent of chocolate and vanilla ice cream sundaes. As the simulation continues, the vortices continue to rotate and even grow, while leaving large regions relatively unmixed.
In the real world, vortices eventually disappear as their energy dissipates due to viscosity. But as this demo shows, they could continue indefinitely in ideal fluids. Although there are no existing fluids with these properties, simulations of the scenario are useful tools for simplifying complex fluid flow problems.
For more on vortices, check out an ultra-detailed model of vortex flow. If you missed previous episodes in this series, visit our archive to see, for example, how to create a spaghetti monster.
Sleek and svelte Ultrabooks and tablets might have stolen the limelight from ye old netbook, but that doesn't mean the less glamorous category is completely bereft of all signs of life. Take for example, Acer's Aspire One 722. Sure, the 1GHz AMD C-50 powered, Radeon HD 6250 wielding netbook's internals got more pizzazz in an updated Europe-only edition, but that didn't stop AT&T from taking the original and giving it a new beginning thanks to shiny new internal WWAN module. Up-to-date silicon it is not, but it could be yours for just $40 a month -- provided you sign your life away on a two-year, 3GB per month, contract. Or alternatively, the HSPA+ redux can be had for the unsubsidized price of $450. Decisions, decisions. Pull the trigger at the source link below.
Contact: Dr. Katrhin Bilgeri kathrin.bilgeri@lmu.de 49-892-180-6938 Ludwig-Maximilians-Universitt Mnchen
How diamond-bearing kimberlites reach the surface
Kimberlites are magmatic rocks that form deep in the Earth's interior and are brought to the surface by volcanic eruptions. On their turbulent journey upwards magmas assimilate other types of minerals, collectively referred to as xenoliths (Greek for "foreign rocks"). The xenoliths found in kimberlite include diamonds, and the vast majority of the diamonds mined in the world today is found in kimberlite ores. Exactly how kimberlites acquire the necessary buoyancy for their long ascent through the Earth's crust has, however, been something of a mystery. An international research team led by Professor Donald Dingwell, Director of the Department of Geo- and Environmental Sciences at LMU, has now demonstrated that assimilated rocks picked up along the way are responsible for the providing the required impetus. The primordial magma is basic, but the incorporation of silicate minerals encountered during its ascent makes the melt more acidic. This leads to the release of carbon dioxide in the form of bubbles, which reduce the density of the melt, essentially causing it to foam. The net result is an increase in the buoyancy of the magma, which facilitates its continued ascent. "Because our results enhance our understanding of the genesis of kimberlite, they will be useful in the search for new diamond-bearing ores and will facilitate the evaluation of existing sources," says Dingwell. (Nature 18. January 2012)
Most known kimberlites formed in the period between 70 and 150 million years ago, but some are over 1200 million years old. Generally speaking, kimberlites are found only in cratons, the oldest surviving areas of continental crust, which form the nuclei of continental landmasses and have remained virtually unchanged since their formation eons ago.
Kimberlitic magmas form about 150 km below the Earth's surface, i.e. at much greater depths than any other volcanic rocks. The temperatures and pressures at such depths are so high that carbon can crystallize in the form of diamonds. When kimberlitic magmas are forced through long chimneys of volcanic origin called pipes, like the water in a hose when the nozzle is narrowed, their velocity markedly increases and the emplaced diamonds are transported upwards as if they were in an elevator. This is why kimberlite pipes are the sites of most of the world's diamond mines. But diamonds are not the only passengers. Kimberlites also carry many other types of rock with them on their long journey into the light.
In spite of this "extra load", kimberlite magmas travel fast, and emerge onto the Earth's surface in explosive eruptions. "It is generally assumed that volatile gases such as carbon dioxide and water vapour play an essential role in providing the necessary buoyancy to power the rapid rise of kimberlite magmas," says Dingwell, "but it was not clear how these gases form in the magma." With the help of laboratory experiments carried out at appropriately high temperatures, Dingwell's team was able to show that the assimilated xenoliths play an important role in the process. The primordial magma deep in the Earth's interior is referred to as basic because it mainly consists of carbonate-bearing components, which may also contain a high proportion of water. When the rising magma comes into contact with silicate-rich rocks, they are effectively dissolved in the molten phase, which acidifies the melt. As more silicates are incorporated, the saturation level of carbon dioxide dissolved in the melt progressively increases as carbon dioxide solubility decreases. When the melt becomes saturated, the excess carbon dioxide forms bubbles. "The result is a continuous foaming of the magma, which may reduce its viscosity and certainly imparts the buoyancy necessary to power its very vehement eruption onto the Earth's surface," as Dingwell explains. The faster the magma rises, the more silicates are entrained in the flow, and the greater the concentration of dissolved silicates until finally the amounts of carbon dioxide and water vapor released thrust the hot melt upward with great force, like a rocket. The new findings also explain why kimberlites are found only in ancient continental nuclei. Only here is the crust sufficiently rich in silica-rich minerals to drive their ascent and, moreover, cratonic crust is exceptionally thick. This means that the journey to the surface is correspondingly longer, and the rising magma has plenty of opportunity to come into contact with silicate-rich minerals.
###
The project was funded by a European Research Council (ERC) Advanced Investigator Grant (EVOKES) and further supported by an LMUexcellent Research Professorship awarded to Donald Dingwell.
(gd)
Publication:
Kimberlite ascent by assimilation-fuelled buoyancy
J.K. Russell, L.A. Porritt, Y. Lavalle, D.B. Dingwell
Nature Advanced Online Publication, 18. January 2012
doi: 10.1038/nature10740
Contact:
Professor Donald B. Dingwell
Department of Geo- and Environmental Sciences, LMU Munich
Phone: +49 89 2180 4136
Fax: +49 89 2180 4176
Email: dingwell@lmu.de
[ | E-mail | Share ]
?
AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert! system.
Contact: Dr. Katrhin Bilgeri kathrin.bilgeri@lmu.de 49-892-180-6938 Ludwig-Maximilians-Universitt Mnchen
How diamond-bearing kimberlites reach the surface
Kimberlites are magmatic rocks that form deep in the Earth's interior and are brought to the surface by volcanic eruptions. On their turbulent journey upwards magmas assimilate other types of minerals, collectively referred to as xenoliths (Greek for "foreign rocks"). The xenoliths found in kimberlite include diamonds, and the vast majority of the diamonds mined in the world today is found in kimberlite ores. Exactly how kimberlites acquire the necessary buoyancy for their long ascent through the Earth's crust has, however, been something of a mystery. An international research team led by Professor Donald Dingwell, Director of the Department of Geo- and Environmental Sciences at LMU, has now demonstrated that assimilated rocks picked up along the way are responsible for the providing the required impetus. The primordial magma is basic, but the incorporation of silicate minerals encountered during its ascent makes the melt more acidic. This leads to the release of carbon dioxide in the form of bubbles, which reduce the density of the melt, essentially causing it to foam. The net result is an increase in the buoyancy of the magma, which facilitates its continued ascent. "Because our results enhance our understanding of the genesis of kimberlite, they will be useful in the search for new diamond-bearing ores and will facilitate the evaluation of existing sources," says Dingwell. (Nature 18. January 2012)
Most known kimberlites formed in the period between 70 and 150 million years ago, but some are over 1200 million years old. Generally speaking, kimberlites are found only in cratons, the oldest surviving areas of continental crust, which form the nuclei of continental landmasses and have remained virtually unchanged since their formation eons ago.
Kimberlitic magmas form about 150 km below the Earth's surface, i.e. at much greater depths than any other volcanic rocks. The temperatures and pressures at such depths are so high that carbon can crystallize in the form of diamonds. When kimberlitic magmas are forced through long chimneys of volcanic origin called pipes, like the water in a hose when the nozzle is narrowed, their velocity markedly increases and the emplaced diamonds are transported upwards as if they were in an elevator. This is why kimberlite pipes are the sites of most of the world's diamond mines. But diamonds are not the only passengers. Kimberlites also carry many other types of rock with them on their long journey into the light.
In spite of this "extra load", kimberlite magmas travel fast, and emerge onto the Earth's surface in explosive eruptions. "It is generally assumed that volatile gases such as carbon dioxide and water vapour play an essential role in providing the necessary buoyancy to power the rapid rise of kimberlite magmas," says Dingwell, "but it was not clear how these gases form in the magma." With the help of laboratory experiments carried out at appropriately high temperatures, Dingwell's team was able to show that the assimilated xenoliths play an important role in the process. The primordial magma deep in the Earth's interior is referred to as basic because it mainly consists of carbonate-bearing components, which may also contain a high proportion of water. When the rising magma comes into contact with silicate-rich rocks, they are effectively dissolved in the molten phase, which acidifies the melt. As more silicates are incorporated, the saturation level of carbon dioxide dissolved in the melt progressively increases as carbon dioxide solubility decreases. When the melt becomes saturated, the excess carbon dioxide forms bubbles. "The result is a continuous foaming of the magma, which may reduce its viscosity and certainly imparts the buoyancy necessary to power its very vehement eruption onto the Earth's surface," as Dingwell explains. The faster the magma rises, the more silicates are entrained in the flow, and the greater the concentration of dissolved silicates until finally the amounts of carbon dioxide and water vapor released thrust the hot melt upward with great force, like a rocket. The new findings also explain why kimberlites are found only in ancient continental nuclei. Only here is the crust sufficiently rich in silica-rich minerals to drive their ascent and, moreover, cratonic crust is exceptionally thick. This means that the journey to the surface is correspondingly longer, and the rising magma has plenty of opportunity to come into contact with silicate-rich minerals.
###
The project was funded by a European Research Council (ERC) Advanced Investigator Grant (EVOKES) and further supported by an LMUexcellent Research Professorship awarded to Donald Dingwell.
(gd)
Publication:
Kimberlite ascent by assimilation-fuelled buoyancy
J.K. Russell, L.A. Porritt, Y. Lavalle, D.B. Dingwell
Nature Advanced Online Publication, 18. January 2012
doi: 10.1038/nature10740
Contact:
Professor Donald B. Dingwell
Department of Geo- and Environmental Sciences, LMU Munich
Phone: +49 89 2180 4136
Fax: +49 89 2180 4176
Email: dingwell@lmu.de
[ | E-mail | Share ]
?
AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert! system.
Roughly ten percent of Americans got a tablet for Christmas, according to figures published by the Pew Research Center. In mid-December, 10 of U.S adults owned a tablet computer. Now, that figure has jumped to 19%, which suggests that ownership doubled in a month. Almost exactly the same numbers were also reported for e-readers. The [...]
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Public release date: 23-Jan-2012
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