The canyon is at least 750km long and in places as much as 800m deep and is on the same scale as parts of the Grand Canyon in Arizona, USA.Link.
This remarkable, previously unknown, feature is thought to predate the ice sheet that has covered Greenland for the last few million years and has the characteristics of a meandering river channel. By comparison, the longest river in the UK, the River Severn, is about 350km long and much less wide and deep.
Professor Jonathan Bamber of Bristol's School of Geographical Sciences, lead author of the study, said: "With Google Streetview available for many cities around the world and digital maps for everything from population density to happiness one might assume that the landscape of the Earth has been fully explored and mapped. Our research shows there's still a lot left to discover."
The scientists used thousands of kilometres of airborne radar data, collected mainly by NASA and researchers from the UK and Germany over several decades, to piece together the landscape lying beneath the ice sheet that covers most of Greenland and obscures it from view.
At certain frequencies, ice is transparent to radio waves which can travel through the ice and bounce off the bedrock underneath. By analysing all the radar data in a consistent way the team discovered a continuous bedrock canyon that extends from almost the centre of the island and ends at its northern extremity in a deep fjord connecting to the Arctic ocean.
They believe the canyon plays an important role in transporting sub-glacial meltwater produced at the bed from the interior to the edge of the ice sheet and ultimately into the ocean. Even before the presence of the ice sheet, going back at least four million years, the evidence suggests the canyon provided a pathway for water from the interior to the coast and was a major fluvial system.
Saturday, August 31, 2013
Friday, August 30, 2013
Russia's defense ministry plans to deploy in 2017 a sophisticated new air missile defense system that can hit targets in space, a senior ministry source told Russian news agencies on Friday.
"The promising S-500 air defense missile system is at the development stage. It's planned to be deployed in 2017," the source was quoted as saying by the Interfax news agency.
The long-range system will be able to destroy targets even if they are in space and cover the whole Russian territory, the source added.
Russia is developing more and more effective missile defense systems for use as a deterrent while opposing plans by the United States to build a missile defense shield in Europe.
If that's a mobile missile I'll shocked.
I would not be shocked if this was vaporware.
Has a fear of robotics ever kept anyone from robbing banks? I'm not talking about the surveillance systems, laser-armed tripwires, noisy alarms, or automated locks on the doors. I'm talking about actual robots—an evolution of the ROOMBA Vacuum cleaner, but with legs, not cute, and definitely not something you want to rob.
Now, an EU-funded, £7.2 million ($11 million USD) collaborative project, called Strands, is underway in England to develop 4D, artificial intelligence for security and care applications. It aims to produce intelligent robo-sentinels that can patrol areas, and learn to detect abnormalities in human behavior. Could their project eventually replace security guards with robots? It looks possible.
Strands, as Nick Hawes of the University of Birmingham said, will "develop novel approaches to extract spatio-temporal structure from sensor data gathered during months of autonomous operation," to develop intelligence that can then "exploit [those] structures to yield adaptive behavior in highly demanding, real-world security and care scenarios."
If we consider the geographical distance and ancient means of transportation, then envisaging Roman influence in Japan seems like an unlikely event. However we are forced to reconsider this outlook since researchers have found glass jewelry belonging to the Roman Empire, in a fifth-century Utsukushi burial mound!
Extensive tests carried out by the Nara National Research Institute for Cultural Properties on the glass jewelry, discovered at the Utsukushi burial mound in Nagaoka, Kyoto Prefecture, date the items between the first and fourth centuries AD. The researchers analyzed the components of 5mm glass beads, which have tiny fragments of gilt attached to them.
Analysis reports that the light yellow beads were made with natron. This was a chemical used by craftsmen in the Roman Empire to melt glass. The beads also have a distinctive hole in them, indicating a multi-layering technique, very predominant of that era. In this method, craftsmen ‘piled up layers of glass’ and quite often put a gold leaf between the layers. This discovery opens up a whole new set of questions on the influence of the Roman Empire and its extent.
Previously unknown archeological sites in forest islands reveal human presence in the western Amazon as early as 10,000 years ago, according to research published August 28 in the open access journal PLOS ONE by Umberto Lombardo from the University of Bern, Switzerland and colleagues from other institutions.
The study focuses on a region in the Bolivian Amazon thought to be rarely occupied by pre-agricultural communities due to unfavorable environmental conditions. Hundreds of 'forest islands'- small forested mounds of earth- are found throughout the region, their origins attributed to termites, erosion or ancient human activity. In this study, the authors report that three of these islands are shell middens, mounds of seashells left by settlers in the early Holocene period, approximately 10,400 years ago.
Samples of soil from these three mounds revealed a dense accumulation of freshwater snail shells, animal bones and charcoal forming the middens. The mounds appear to have formed in two phases: an older layer composed primarily of snail shells, and an overlying layer composed of organic matter containing pottery, bone tools and human bones. The two are separated by a thin layer rich in pieces of burnt clay and earth, and the uppermost layer of deposits was also seen to contain occasional fragments of earthenware pottery. Radiocarbon analysis of two middens indicates that humans settled in this region during the early Holocene, approximately 10,400 years ago, and shells and other artefacts built up into mounds over an approximately 6,000 year period of human use. The sites may have been abandoned as climate shifted towards wetter conditions later. Lombardo adds, "We have discovered the oldest archaeological sites in western and southern Amazonia. These sites allow us to reconstruct 10,000 years of human-environment interactions in the Bolivian Amazon."
Scientists expect the future climate to become warmer, and that this will apply to the Arctic in particular. Here the temperature is expected to increase considerably more than the average on Earth, according to the Intergovernmental Panel on Climate Change average scenario (A1B).Link.
What will this mean for Greenland? A very significant change will be the emergence of forests, where there are currently only four species of trees and large bushes indigenous to Greenland – and they only grow in small areas in the south.
An international research group including Professor of Biology Jens-Christian Svenning, Aarhus University, has analysed which species will be able to grow in the climate expected in Greenland in 2100. The analysis shows that a majority of 44 relevant species of North American and European trees and bushes will be able to grow in Greenland in the future.
In fact, the analysis points to the fact that a considerable number of species would already be able to grow in Greenland today. This is supported by actual experiments, where various species of trees have been planted in Greenland, including Siberian larch, white spruce, lodgepole pine and Eastern balsam poplar.
By the end of the century, a key species like the Arctic dwarf birch will probably be able to find suitable habitats in most areas of Greenland that are currently ice-free, far beyond its current distribution. Here we are talking about more than 400,000 square kilometres, or an area almost the size of Sweden.
Phylogeny and tempo of diversification in the superradiation of spiny-rayed fishes
1. Thomas J. Neara,1,
2. Alex Dornburga,
3. Ron I. Eytana,
4. Benjamin P. Keckb,
5. W. Leo Smithc,
6. Kristen L. Kuhna,
7. Jon A. Moored,
8. Samantha A. Pricee,
9. Frank T. Burbrinkf,
10. Matt Friedmang, and
11. Peter C. Wainwrighte
a. Department of Ecology and Evolutionary Biology and Peabody Museum of Natural History, Yale University, New Haven, CT 06520;
b. Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN 37996;
c. Division of Fishes, The Field Museum, Chicago, IL 60605;
d. Wilkes Honors College and Harbor Branch Oceanographic Institution, Florida Atlantic University, Jupiter, FL 33458;
e. Department of Evolution and Ecology, University of California, Davis, CA 95616;
f. Biology Department, College of Staten Island/City University of New York, Staten Island, NY 10314; and
g. Department of Earth Sciences, University of Oxford, Oxford OX1 3AN, United Kingdom
Spiny-rayed fishes, or acanthomorphs, comprise nearly one-third of all living vertebrates. Despite their dominant role in aquatic ecosystems, the evolutionary history and tempo of acanthomorph diversification is poorly understood. We investigate the pattern of lineage diversification in acanthomorphs by using a well-resolved time-calibrated phylogeny inferred from a nuclear gene supermatrix that includes 520 acanthomorph species and 37 fossil age constraints. This phylogeny provides resolution for what has been classically referred to as the “bush at the top” of the teleost tree, and indicates acanthomorphs originated in the Early Cretaceous. Paleontological evidence suggests acanthomorphs exhibit a pulse of morphological diversification following the end Cretaceous mass extinction; however, the role of this event on the accumulation of living acanthomorph diversity remains unclear. Lineage diversification rates through time exhibit no shifts associated with the end Cretaceous mass extinction, but there is a global decrease in lineage diversification rates 50 Ma that occurs during a period when morphological disparity among fossil acanthomorphs increases sharply. Analysis of clade-specific shifts in diversification rates reveal that the hyperdiversity of living acanthomorphs is highlighted by several rapidly radiating lineages including tunas, gobies, blennies, snailfishes, and Afro-American cichlids. These lineages with high diversification rates are not associated with a single habitat type, such as coral reefs, indicating there is no single explanation for the success of acanthomorphs, as exceptional bouts of diversification have occurred across a wide array of marine and freshwater habitats.
Thursday, August 29, 2013
It has been the summer of biotech. After years of fretting that investors had soured on the high-risk industry, untested biotechnology companies are all of a sudden going public. This year, 24 US firms have issued initial public offerings (IPOs), pumping US$1.8 billion into the industry. Their stocks rose an average of 20% on the first day of trading. Another eight companies plan to follow suit in the coming months.
If they do, it will be a record-setting year for biotechnology. Each new deal has amped up the excitement. But there is also anxiety that the field could be in a bubble. “It will be a cycle, and this cycle will eventually run its course,” says Noubar Afeyan, managing partner at venture-capital firm Flagship Ventures in Cambridge, Massachusetts. “These things end up appearing and disappearing for reasons that people can only explain in hindsight.”
Saturn’s largest moon, Titan, is one of the solar system’s most fascinating destinations. It’s the second biggest moon in the solar system and the only one known to possess a thick atmosphere. The Cassini-Huygens mission has found it to be weirdly Earth-like, with rocky plains, languid lakes and even precipitation — only the world is so cold the rocks are probably water ice, and the lakes liquid methane. Now even its interior is giving up secrets, thanks to the gravitational data Cassini’s been gathering in its orbit around Saturn.
Astronomers had already suspected that Titan’s surface was a shell of water ice, with a subsurface (water) ocean lurking beneath. The new data, published in Nature this week, reveal that it’s a stronger, more rigid shell than previously thought, measuring at least 25 miles thick, and dozens of times more in some places.
Pop sci write up.
The last glacial maximum was a time when Earth's far northern and far southern latitudes were largely covered in ice sheets and sea levels were low. Over much of the planet, glaciers were at their greatest extent roughly 20,000 years ago. But according to a study headed by University of Pennsylvania geologist Jane Willenbring, that wasn't true in at least one part of southern Europe. Due to local effects of temperature and precipitation, the local glacial maximum occurred considerably earlier, around 26,000 years ago.
The finding sheds new light on how regional climate has varied over time, providing information that could lead to more-accurate global climate models, which predict what changes Earth will experience in the future.
Willenbring, an assistant professor in Penn's Department of Earth and Environmental Science in the School of Arts and Sciences, teamed with researchers from Spain, the United Kingdom, China and the United States to pursue this study of the ancient glaciers of southern Europe.
"We wanted to unravel why and when glaciers grow and shrink," Willenbring said.
In the study site in central Spain, it is relatively straightforward to discern the size of ancient glaciers, because the ice carried and dropped boulders at the margin. Thus a ring of boulders marks the edge of the old glacier.
It is not as easy to determine what caused the glacier to grow, however. Glaciers need both moisture and cold temperatures to expand. Studying the boulders that rim the ancient glaciers alone cannot distinguish these contributions. Caves, however, provide a way to differentiate the two factors. Stalagmites and stalactites — the stony projections that grow from the cave floor and ceiling, respectively — carry a record of precipitation because they grow as a result of dripping water.
"If you add the cave data to the data from the glaciers, it gives you a neat way of figuring out whether it was cold temperatures or higher precipitation that drove the glacier growth at the time," Willenbring said.
The researchers conducted the study in three of Spain's mountain ranges: the Bejár, Gredos and Guadarrama. The nearby Eagle Cave allowed them to obtain indirect precipitation data.
To ascertain the age of the boulders strewn by the glaciers and thus come up with a date when glaciers were at their greatest extent, Willenbring and colleagues used a technique known as cosmogenic nuclide exposure dating, which measures the chemical residue of supernova explosions. They also used standard radiometric techniques to date stalagmites from Eagle Cave, which gave them information about fluxes in precipitation during the time the glaciers covered the land.
"Previously, people believe the last glacial maximum was somewhere in the range of 19-23,000 years ago," Willenbring said. "Our chronology indicates that's more in the range of 25-29,000 years ago in Spain."
The geologists found that, although temperatures were cool in the range of 19,000-23,000 years ago, conditions were also relatively dry, so the glaciers did not regain the size they had obtained several thousand years earlier, when rain and snowfall totals were higher. They reported their findings in the journal Scientific Reports.
Tree Migration-Rates: Narrowing the Gap between Inferred Post-Glacial Rates and Projected Rates
1. Angelica Feurdean (a,b)
2. Shonil A. Bhagwat (c,d,e,f)
3. Katherine J. Willis (d,e)
4. H. John B Birks (c,g,h)
5. Heike Lischke (i)
6. Thomas Hickler (a,j)
a. Senckenberg Research Institute and Natural History Museum and Biodiversity and Climate Research Center, Frankfurt am Main, Germany
b. Romanian Academy “Emil Racoviţă” Institute of Speleology, Cluj Napoca, Romania
c. Department of Geography, The Open University, Milton Keynes, United Kingdom
d. School of Geography and the Environment, University of Oxford, Oxford, United Kingdom
e. Long-Term Ecology Laboratory, Biodiversity Institute, Department of Zoology, University of Oxford, Oxford, United Kingdom
f. Biodiversity Institute, Oxford Martin Institute, Department of Zoology, University of Oxford, Oxford, United Kingdom
g. Department of Biology, University of Bergen, Bergen, Norway
h. Environmental Change Research Centre, University College London, London, United Kingdom
i. Dynamic Macroecology, Landscape Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
j. Biodiversity and Climate Research Centre and Senckenberg Gesellschaft für Naturforschung and Goethe University, Frankfurt am Main, Germany
Faster-than-expected post-glacial migration rates of trees have puzzled ecologists for a long time. In Europe, post-glacial migration is assumed to have started from the three southern European peninsulas (southern refugia), where large areas remained free of permafrost and ice at the peak of the last glaciation. However, increasing palaeobotanical evidence for the presence of isolated tree populations in more northerly microrefugia has started to change this perception. Here we use the Northern Eurasian Plant Macrofossil Database and palaeoecological literature to show that post-glacial migration rates for trees may have been substantially lower (60–260 m yr–1) than those estimated by assuming migration from southern refugia only (115–550 m yr–1), and that early-successional trees migrated faster than mid- and late-successional trees. Post-glacial migration rates are in good agreement with those recently projected for the future with a population dynamical forest succession and dispersal model, mainly for early-successional trees and under optimal conditions. Although migration estimates presented here may be conservative because of our assumption of uniform dispersal, tree migration-rates clearly need reconsideration. We suggest that small outlier populations may be a key factor in understanding past migration rates and in predicting potential future range-shifts. The importance of outlier populations in the past may have an analogy in the future, as many tree species have been planted beyond their natural ranges, with a more beneficial microclimate than their regional surroundings. Therefore, climate-change-induced range-shifts in the future might well be influenced by such microrefugia.
A new, richly fossiliferous member comprised of tidal deposits in the Upper Cretaceous Maevarano Formation, northwestern Madagascar
1. Raymond R. Rogers (a)
2. David W. Krause (b)
3. Sophia C. Kast (a)
4. Madeline S. Marshall (a, c)
5. Lydia Rahantarisoa (d)
6. Colin R. Robins (e)
7. Joseph J.W. Sertich (f)
a. Geology Department, Macalester College, Saint Paul, MN 55105, USA
b. Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY 11794, USA
c. Department of Geophysical Sciences, University of Chicago, Chicago, IL 60637, USA
d. Département de Paléontologie, Université d'Antananarivo, Antananarivo (101), Madagascar
e. W.M. Keck Science Department, Claremont McKenna, Pitzer, and Scripps Colleges, Claremont, CA 91711, USA
f. Department of Earth Sciences, Denver Museum of Nature and Science, Denver, CO 80205, USA
A new member of the Upper Cretaceous (Maastrichtian) Maevarano Formation is proposed to accommodate a distinctive succession of strata exposed along the shores of Lac Kinkony in northwestern Madagascar. The new Lac Kinkony Member overlies fully terrestrial sandstones of the Anembalemba Member of the Maevarano Formation, and is capped by marine dolostones of the Berivotra Formation. In the stratotype section, the base of the Lac Kinkony Member consists of siltstone interbeds that host networks of Ophiomorpha. Siltstone facies pass up-section to distinctive white sandstones packed with dolomitic mud matrix that exhibit rhythmic clay drapes, flaser and wavy bedding, and oppositely-oriented ripples developed on the toes of larger foresets. Thin flat interbeds of microgranular dolostone and claystone comprise the uppermost facies of the Lac Kinkony Member, and a laterally traceable ravinement bed mantled by cobbles of rounded dolostone marks the contact with the superjacent Berivotra Formation. Deposits of the Lac Kinkony Member are interpreted to represent siliciclastic and carbonate tidal flats dissected by tidally-influenced rivers. Vertebrate fossils are abundantly preserved in these coastal deposits, and are locally concentrated in microfossil bonebeds that have the potential to yield thousands of small identifiable specimens. In addition to many taxa already known from the Maevarano Formation, the Lac Kinkony Member has yielded a wealth of phyllodontid albuloid fish skull elements, the distal humerus of a new frog taxon, five vertebrae representing two new snakes, a tooth of a possible dromaeosaurid, and a complete skull of a new mammal. The discovery of several new vertebrate taxa from this new member reflects the fact that it samples a previously unsampled nearshore, peritidal paleoenvironment in the Late Cretaceous of Madagascar.
The mammal skull is exciting.
(that's a pic of the cancelled MiG Skat)
Russian designers are proceeding with development of an unmanned “sixth-generation” fighter jet, former Air Force chief Pyotr Deinekin said Monday. “The sixth generation of aircraft will most likely be pilotless. Naturally, we are actively working on this,” Deinekin said in an interview with RIA Novosti.
Russia will probably not be able to skip a generation and will need to complete all of its fifth-generation projects, he added.
Russia is currently testing its prototype fifth-generation Sukhoi T-50 fighter, a manned aircraft that made its first public appearance two years ago. The US is introducing its F-35, and European powers such as the UK and France have their Typhoon and Rafale fighters in service. All those nations have carried out research into pilotless designs, analysts say.
Deinekin did not specify which design bureaus were working on pilotless sixth-generation designs, but Russian military aircraft maker MiG said in May it was ready to go ahead with a research and development project for an unmanned combat air vehicle (UCAV) based on its Skat prototype, after signing a deal with the Trade and Industry Ministry earlier that month.
The T-50 display at MAKS is tamer than some people hoped. Despite the statements of political and industry leaders, I suspect that the fighter won't be in service for some years, expect possibly in the form of a small test squadron, because what the Russian industry has set out to do is difficult by any standard.
Some of the clues to the fighter's development here also suggest that the T-50 will not constitute the entire fighter force for a long time, if ever. The Tactical Missiles Corporation exhibit booth points to two things: a robust weapons development program for the conventional Su-35S, and a "kick the door down" mission for the stealth fighter.
Absent here is any sign of all-new weapons for the T-50, which instead looks likely to enter service with refined versions of existing systems. Interestingly, the closest that the T-50 (so far) is confirmed to be getting to an all-new weapon is a highly modified version of an existing anti-radar missile, the folding-wing Kh-58UShE.
Wednesday, August 28, 2013
They have a higher energy density than the LiPo batteries, but the only source I can find for publicly purchasable batteries is an electric bike maker. Their form factor is much too large. And I'd rather not purchase their equipment to tear it apart to make something else.
Boeing officials are planning upgrades for the F-15 beyond those outlined for Saudi Arabia and offered to South Korea, but the company is mum on precisely what is next for the workhorse fighter.
South Korean procurement authorities are expected to announce their choice for a tender of 60 fighters in mid-September, says Steve Winkler, Boeing’s director of business development for the F-15 program.
The Saudi buy of F-15s carries the company’s production line, based in St. Louis, through 2018. A South Korean buy would add about three more years to the life of the production line, Winkler said.
Final bids and pricing were submitted to South Korea Aug. 16. With the Eurofighter Typhoon eliminated from the competition, it is now between the F-15 Silent Eagle and Lockheed Martin’s F-35, which is thought to be more expensive.
With conformal tanks configured to carry weapons internally, Winkler says the F-15 Strike Eagle has front-aspect stealth qualities.
Korea Aerospace Industries is designing the conformal weapons bay and Israel Aerospace Industries is designing the conformal fuel tanks.
Some radar cross-section reduction work is expected to be done to the early stages of the engine and inlet to improve low-observability properties. Winkler declined to say specifically what this work is, but said the design work has already been done and this effort is not developmental.
I half wonder if Boeing is hedging against the possibility the US will have to "upgrade" F-15s because we bought so few F-22s and the cost of the F-35 is so high...
Authors:1. Paul Robertson (a)2. Michael Endl (a)3. William D. Cochran (a)4. Phillip J. MacQueen (a)5. Alan P. Boss (b)Affiliations:a. Department of Astronomy and McDonald Observatory, University of Texas at Austin, Austin, TX 78712, USAb. Department of Terrestrial Magnetism, Carnegie Institution, 5241 Broad Branch Road, NW, Washington DC 20015-1305, USAAbstract:We announce the discovery of a ~2 Jupiter-mass planet in an eccentric 11 yr orbit around the K7/M0 dwarf GJ 328. Our result is based on 10 years of radial velocity (RV) data from the Hobby-Eberly and Harlan J. Smith telescopes at McDonald Observatory, and from the Keck Telescope at Mauna Kea. Our analysis of GJ 328's magnetic activity via the Na I D features reveals a long-period stellar activity cycle, which creates an additional signal in the star's RV curve with amplitude 6-10 m s–1. After correcting for this stellar RV contribution, we see that the orbit of the planet is more eccentric than suggested by the raw RV data. GJ 328b is currently the most massive, longest-period planet discovered around a low-mass dwarf.
Yep. Our supercomputer, Franklin (affectionately called Cranky Franky, now decommissioned and replaced with Edison) was hacked. Here's the story. If I am given permission, I'll write up more: I need to tread very carefully here. I will say there's a huge story which isn't in the Wired article.
Mammal Morphology Has Roots in the Massively Creative Destruction of Permian Triassic Mass Extinction
The radiation of cynodonts and the ground plan of mammalian morphological diversity
1. Marcello Ruta (a)
2. Jennifer Botha-Brink (b,c)
3. Stephen A. Mitchell (d)
4. Michael J. Benton (d)
a. School of Life Sciences, University of Lincoln, Lincoln LN2 2LG, UK
b. Karoo Palaeontology, National Museum, PO Box 266, Bloemfontein 9300, South Africa
c. Department of Zoology and Entomology, University of the Free State, Bloemfontein 9300, South Africa
d. School of Earth Sciences, University of Bristol, Bristol BS8 1RJ, UK
Cynodont therapsids diversified extensively after the Permo-Triassic mass extinction event, and gave rise to mammals in the Jurassic. We use an enlarged and revised dataset of discrete skeletal characters to build a new phylogeny for all main cynodont clades from the Late Permian to the Early Jurassic, and we analyse models of morphological diversification in the group. Basal taxa and epicynodonts are paraphyletic relative to eucynodonts, and the latter are divided into cynognathians and probainognathians, with tritylodonts and mammals forming sister groups. Disparity analyses reveal a heterogeneous distribution of cynodonts in a morphospace derived from cladistic characters. Pairwise morphological distances are weakly correlated with phylogenetic distances. Comparisons of disparity by groups and through time are non-significant, especially after the data are rarefied. A disparity peak occurs in the Early/Middle Triassic, after which period the mean disparity fluctuates little. Cynognathians were characterized by high evolutionary rates and high diversity early in their history, whereas probainognathian rates were low. Community structure may have been instrumental in imposing different rates on the two clades.
In situ δ18O and Mg/Ca analyses of diagenetic and planktic foraminiferal calcite preserved in a deep-sea record of the paleocene-eocene thermal maximumAuthors:1. Reinhard Kozdon (a)2. D. C. Kelly (a)3. K. Kitajima (a)4. A. Strickland (a)5. J. H. Fournelle (a)6. J. W. Valley (a)Affiliation:a. WiscSIMS, Dept. of Geoscience, University of Wisconsin, Madison, 1215 W. Dayton St., Madison,WI 53706, USAAbstract:We report δ18O and minor-element (Mg/Ca, Sr/Ca) data acquired by high-resolution, in situ secondary ion mass spectrometry (SIMS) from planktic foraminiferal shells and 100–500 µm sized diagenetic crystallites recovered from a deep-sea record (ODP Site 865) of the Paleocene-Eocene thermal maximum (PETM). The δ18O of crystallites (~1.2‰ PDB) is ~4.8‰ higher than that of planktic foraminiferal calcite (−3.6‰ PDB), while crystallite Mg/Ca and Sr/Ca ratios are slightly higher and substantially lower than in planktic foraminiferal calcite, respectively. The focused stratigraphic distribution of the crystallites signals an association with PETM conditions; hence, we attribute their formation to early diagenesis initially sourced by seafloor dissolution (burndown) ensued by reprecipitation at higher carbonate saturation. The Mg/Ca ratios of the crystallites are an order of magnitude lower than those predicted by inorganic precipitation experiments, which may reflect a degree of inheritance from ‘donor’ phases of biogenic calcite that underwent solution in the sediment column. In addition, SIMS δ18O and electron microprobe Mg/Ca analyses taken within a planktic foraminiferal shell yield parallel increases along traverses that coincide with muricae-blades on the chamber wall. The parallel δ18O and Mg/Ca increases indicate a diagenetic origin for the blades, but their δ18O value (−0.5‰ PDB) is lower than that of crystallites suggesting that these two phases of diagenetic carbonate formed at different times. Finally, we posit that elevated levels of early diagenesis acted in concert with sediment mixing and carbonate dissolution to attenuate the δ18O decrease signaling PETM warming in ‘whole-shell’ records published for Site 865.
An international team of paleontologists says it's found remains of the world's largest fish, a 50-foot giant that swam in Earth's oceans 160 million years ago.The findings about Leedsichthys, a huge, bony, plankton-eating fish, reveal an important missing piece in the evolutionary story of fish, mammals and ocean ecosystems, a release from the University of Glasgow said Monday.Just as dinosaurs on land evolved to created animals of huge dimensions, sea creatures also started to grow to vast proportions in the Jurassic era, they said."The process is known as gigantism," Jeff Liston of the National Museums of Scotland said. "It was known about in land animals at the time but we had no way of knowing if a parallel process occurred in the oceans. We now know that it did -- though the reason for appearance of these gigantic beasts, both on land and in the water, is not clear at present.""The giant plankton-feeders we know to live in today's oceans are among the largest living vertebrate animals alive," he said. "The Leedsichthys was the first animal known to occupy this role.
Brian has a great post on the subject.
Supervolcanoes, such as the one sitting dormant under Yellowstone National Park, are capable of producing eruptions thousands of times more powerful than normal volcanic eruptions. While they only happen every several thousand years, these eruptions have the potential to kill millions of people and animals due to the massive amount of heat and ash they release into the atmosphere. Now, researchers at the University of Missouri have shown that the ash produced by supervolcanoes can be so hot that it has the ability to turn back into lava once it hits the ground tens of miles away from the original eruption.
Following a volcanic eruption, lava typically flows directly from the site of the eruption until it cools enough that it hardens in place. However, researchers found evidence of an ancient lava flow tens of miles away from a supervolcano eruption near Yellowstone that occurred around 8 million years ago. Previously, Graham Andrews, an assistant professor at California State University Bakersfield, found that this lava flow was made of ash ejected during the eruption. Following Andrew's discovery, Alan Whittington, an associate professor in the University of Missouri department of geological sciences in the College of Arts and Science, along with lead author Genevieve Robert and Jiyang Ye, both doctoral students in the geological sciences department, determined how this was possible.
"During a supervolcano eruption, pyroclastic flows, which are giant clouds of very hot ash and rock, travel away from the volcano at typically a hundred miles an hour," Robert said. "We determined the ash must have been exceptionally hot so that it could actually turn into lava and flow before it eventually cooled."
Because the ash should have cooled too much in the air to turn into lava right as it landed, the researchers believe the phenomenon was made possible by a process known as "viscous heating." Viscosity is the degree to which a liquid resists flow. The higher the viscosity, the less the substance can flow. For example, water has a very low viscosity, so it flows very easily, while molasses has a higher viscosity and flows much slower. Whittington likens the process of viscous heating to stirring a pot of molasses.
Tuesday, August 27, 2013
The subject of offensive cyber action by the U.S. government was classified for many years and was hardly discussed in public at all. Then several years ago the possibility of U.S. cyber offense was formally acknowledged, though it was mostly discussed in the conditional mood, as a capability that might be developed and employed under certain hypothetical circumstances.
Today, however, U.S. offensive cyber warfare is treated as an established fact. Not only that but, officials say, the U.S. military is pretty good at it.
“We believe our [cyber] offense is the best in the world,” said Gen. Keith B. Alexander, director of the National Security Agency and Commander of U.S. Cyber Command. His comments appeared in newly published answers to questions for the record from a March 2013 hearing of the House Armed Services Committee (at p. 87).
“Cyber offense requires a deep, persistent and pervasive presence on adversary networks in order to precisely deliver effects,” Gen. Alexander explained in response to a question from Rep. Trent Franks (R-AZ). “We maintain that access, gain deep understanding of the adversary, and develop offensive capabilities through the advanced skills and tradecraft of our analysts, operators and developers. When authorized to deliver offensive cyber effects, our technological and operational superiority delivers unparalleled effects against our adversaries’ systems.”
“Potential adversaries are demonstrating a rapidly increasing level of sophistication in their offensive cyber capabilities and tactics. In order for the Department of Defense to deny these adversaries an asymmetric advantage, it is essential that we continue the rapid development and resourcing of our Cyber Mission Forces.”
Boeing's F-15SE Silent Eagle has been selected as the only qualified bidder in South Korea's F-X Phase 3 competition for 60 fighters—but the country's air force is lobbying to overturn the decision in favor of the Lockheed Martin F-35 Joint Strike Fighter.
A win in South Korea would extend the F-15 production line into the next decade and launch an improved version that could compete for future fighter requirements in the 2020s. That outcome seems likely following the decision of the South Korean purchasing authority, the Defense Acquisition Program Agency (DAPA), to eliminate first the F-35 as too costly and then the Eurofighter Typhoon for a bidding irregularity—although EADS, representing the consortium in the South Korean deal, disputes DAPA's decision.
A cross-government committee chaired by Defense Minister Kim Kwan-jin will meet next month to rule on DAPA's decision. The review group will include air force officers, a member of the parliament's defense committee, an official from the finance ministry and the heads of DAPA and the Agency for Defense Development, which wants to lead indigenous industry in the development of its own stealthy fighter, the KF-X (AW&ST April 29, p. 46).
The finance ministry may back DAPA's fiscally conservative choice, but the air force has already shown its colors in fighting for the F-35.
“Some in the air force complain that the F-X Phase 3 is veering onto a wrong course, contrary to original aims,” the Yonhap news agency reported Aug. 20, a few days after DAPA's decision was disclosed. The “original aim,” as seen by the unnamed officers quoted by Yonhap, was evidently an F-35 order, and their attitude seems to be that the other two contenders were invited to bid just for the sake of creating competition.
This is a sensitive point.
A SYSTEMATIC SEARCH FOR TROJAN PLANETS IN THE KEPLER DATA
1. Markus Janson (a)
a. Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA
b. Hubble Fellow
Trojans are circumstellar bodies that reside in characteristic 1:1 orbital resonances with planets. While all the trojans in our solar system are small (lsim100 km), stable planet-size trojans may exist in extrasolar planetary systems, and the Kepler telescope constitutes a formidable tool to search for them. Here we report on a systematic search for extrasolar trojan companions to 2244 known Kepler Objects of Interest (KOIs), with epicyclic orbital characteristics similar to those of the Jovian trojan families. No convincing trojan candidates are found, despite a typical sensitivity down to Earth-size objects. This fact, however, cannot be used to stringently exclude the existence of trojans in this size range, since stable trojans need not necessarily share the same orbital plane as the planet, and thus may not transit. Following this reasoning, we note that if Earth-sized trojans exist at all, they are almost certainly both present and in principle detectable in the full set of Kepler data, although a very substantial computational effort would be required to detect them. Additionally, we also note that some of the existing KOIs could in principle be trojans themselves, with a primary planet orbiting outside of the transiting plane. A few examples are given for which this is a readily testable scenario.
DO GIANT PLANETS SURVIVE TYPE II MIGRATION?
1. Yasuhiro Hasegawa (a,c)
2. Shigeru Ida (b)
a. Institute of Astronomy and Astrophysics, Academia Sinica (ASIAA), Taipei 10641, Taiwan
b. Earth-Life Science Institute, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152-8551, Japan
c. EACOA fellow
Planetary migration is one of the most serious problems to systematically understand the observations of exoplanets. We clarify that the theoretically predicted type II, migration (like type I migration) is too fast, by developing detailed analytical arguments in which the timescale of type II migration is compared with the disk lifetime. In the disk-dominated regime, the type II migration timescale is characterized by a local viscous diffusion timescale, while the disk lifetime is characterized by a global diffusion timescale that is much longer than the local one. Even in the planet-dominated regime where the inertia of the planet mass reduces the migration speed, the timescale is still shorter than the disk lifetime except in the final disk evolution stage where the total disk mass decays below the planet mass. This suggests that most giant planets plunge into the central stars within the disk lifetime, and it contradicts the exoplanet observations that gas giants are piled up at r gsim 1 AU. We examine additional processes that may arise in protoplanetary disks: dead zones, photoevaporation of gas, and gas flow across a gap formed by a type II migrator. Although they make the type II migration timescale closer to the disk lifetime, we show that none of them can act as an effective barrier for rapid type II migration with the current knowledge of these processes. We point out that gas flow across a gap and the fraction of the flow accreted onto the planets are uncertain and they may have the potential to solve the problem. Much more detailed investigation for each process may be needed to explain the observed distribution of gas giants in extrasolar planetary systems.
University of Washington researchers have performed what they believe is the first noninvasive human-to-human brain interface, with one researcher able to send a brain signal via the Internet to control the hand motions of a fellow researcher.LINK!
Using electrical brain recordings and a form of magnetic stimulation, Rajesh Rao sent a brain signal to Andrea Stocco on the other side of the UW campus, causing Stocco's finger to move on a keyboard.
While researchers at Duke University have demonstrated brain-to-brain communication between two rats, and Harvard researchers have demonstrated it between a human and a rat, Rao and Stocco believe this is the first demonstration of human-to-human brain interfacing.
"The Internet was a way to connect computers, and now it can be a way to connect brains," Stocco said. "We want to take the knowledge of a brain and transmit it directly from brain to brain."
The researchers captured the full demonstration on video recorded in both labs. The version available at the end of this release has been edited for length.
Rao, a UW professor of computer science and engineering, has been working on brain-computer interfacing (BCI) in his lab for more than 10 years and just published a textbook on the subject. In 2011, spurred by the rapid advances in BCI technology, he believed he could demonstrate the concept of human brain-to-brain interfacing. So he partnered with Stocco, a UW research assistant professor in psychology at the UW's Institute for Learning & Brain Sciences.
On Aug. 12, Rao sat in his lab wearing a cap with electrodes hooked up to an electroencephalography machine, which reads electrical activity in the brain. Stocco was in his lab across campus wearing a purple swim cap marked with the stimulation site for the transcranial magnetic stimulation coil that was placed directly over his left motor cortex, which controls hand movement.
The team had a Skype connection set up so the two labs could coordinate, though neither Rao nor Stocco could see the Skype screens.
Rao looked at a computer screen and played a simple video game with his mind. When he was supposed to fire a cannon at a target, he imagined moving his right hand (being careful not to actually move his hand), causing a cursor to hit the "fire" button. Almost instantaneously, Stocco, who wore noise-canceling earbuds and wasn't looking at a computer screen, involuntarily moved his right index finger to push the space bar on the keyboard in front of him, as if firing the cannon. Stocco compared the feeling of his hand moving involuntarily to that of a nervous tic.
Somewhere south of Newcastle, amid the wide-open prairie and rolling hills, rests a mass grave. A femur here. A tooth there. A tip of a tail barely poking through the ground somewhere else.
The cause of death is unknown. It could have been a lightning strike, disease or an attack by a band of marauding T. rexes.
The victims: At least four U-Haul-sized, plant-eating triceratopses.
Paleontologists worked for two months this summer and found 250 bones. Only 950 more to go.
On a hot day in mid-August, one paleontologist held up a pterygoid for inspection. A pterygoid is a portion of a triceratops palette in its skull. It’s roughly the size of a loaf of bread, and had never previously been found complete and alone.
Tonian/Cryogenian Age for Original Depositional Age of Metacarbonate Rocks in Sør Rondane Mountains, East Antarctica
Late-Tonian to early-Cryogenian apparent depositional ages for metacarbonate rocks from the Sør Rondane Mountains, East Antarctica
1. Naho Otsuji (a)
2. M. Satish-Kumar (a, b)
3. Atsushi Kamei (c)
4. Noriyoshi Tsuchiya (d)
5. Tetsuo Kawakami (e)
6. Masahiro Ishikawa (f)
7. Geoffrey H. Grantham (g)
a. Graduate School of Science and Technology, Niigata University, 2-8050 Ikarashi, Nishi-ku, Niigata 950-2181, Japan
b. Department of Geology, Niigata University, 2-8050 Ikarashi, Nishi-ku, Niigata 950-2181, Japan
c. Department of Geosciences, Shimane University, Matsue 690-8504, Japan
d. Graduate School of Environmental Studies, Tohoku University, Aramaki, Aoba, Sendai 980-9579, Japan
e. Department of Geology and Mineralogy, Kyoto University, Kitashirakawa-oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan
f. Graduate School of Environment and Information Sciences, Yokahama National University, Tokiwadai, Hodogaya-ku, Yokohama 248-501, Japan
g. Council for Geoscience, P/Bag X112, Pretoria, South Africa
The Sør Rondane Mountains (SRM), located in the Neoproterozoic to Early Cambrian East African-Antarctic collisional orogen is composed of medium- to high-grade metasedimentary, metaigneous and intrusive rocks of diverse composition. Within the metasedimentary rocks, the metacarbonate rocks are considered to have deposited chemically in the so-called the “Mozambique Ocean” that separated the continental blocks that amalgamated to form Gondwana and possibly record geochemical signatures of contemporaneous seawater. Here we attempt to constrain the apparent age of sedimentation of metasedimentary sequences using strontium isotope chemostratigraphy of the least altered metacarbonate rocks. Pure metacarbonate samples, collected during the 51st Japanese Antarctic Research Expedition from different regions throughout the SRM, were selected based on careful screening using multiple geochemical parameters, such as carbon and oxygen isotopic composition and trace and rare earth element contents. We could successfully test the extent of alteration for the Sør Rondane metacarbonate samples, using Mn/Sr ratios, which show a positive correlation with 87Sr/86Sr ratios. After a rigorous geochemical screening in terms of post-depositional alterations, 18 samples were identified as least altered. These samples collectively gave regional initial 87Sr/86Sr ratios between 0.70566 and 0.70630, from Balchen, Brattnipene, Menipa and Tanngarden regions of the SRM, with the exception of Perlebandet region. These Sr isotopic ratios reflect seawater compositions of late-Tonian and early-Cryogenian age (880–850 Ma and 820–790 Ma), when compared with the evolution of Sr isotopes in the Neoproterozoic Oceans. Furthermore, these estimates are consistent with the carbon isotope chemostratigraphic curves of Neoproterozoic. The estimated apparent depositional ages of carbonate rocks in the SRM are also conformable with the reported detrital and metamorphic ages for this region. Carbonate rocks in the Perlebandet region shows low initial Sr isotope ratio (0.70482), suggesting that these rocks may have deposited earlier than other carbonate rocks in the SRM. Our results can be correlated with the chemostratigraphic depositional ages reported for carbonates from the Montepuetz Complex, Mozambique, suggesting the presence of contemporaneous platform environment on both sides of the possible suture. The finding of late-Tonian and early-Cryogenian carbonate deposition, potentially points toward a platform environment surrounding the tonalitic continental arc in the SW region of the SRM, prior to the amalgamation of Gondwana. The results obtained need to be tested with similar studies on metacarbonate sequences from the surrounding regions, which would help to resolve the processes and sequence of collision events that finally amalgamated Gondwana.
When Francis Crick and James Watson discovered the double helical structure of deoxyribonucleic acid (DNA) in 1953, it began a genetic revolution to map, study, and sequence the building blocks of living organisms.link.
DNA encodes the genetic material passed on from generation to generation. For the information encoded in the DNA to be made into the proteins and enzymes necessary for life, ribonucleic acid (RNA), single-stranded genetic material found in the ribosomes of cells, serve as intermediary. Although usually single-stranded, some RNA sequences were predicted to have the ability to form a double helix, much like DNA.
In 1961, Alexander Rich along with David Davies, Watson, and Crick, hypothesized that the RNA known as poly (rA) could form a parallel-stranded double helix based on the results of fibre diffraction experiments.
Fifty years later, scientists from McGill University successfully crystallized a short RNA sequence, poly (rA)11, and used data collected at the Canadian Light Source (CLS) and the Cornell High Energy Synchrotron to confirm the hypothesis of a poly (rA) double-helix.
The detailed 3D structure of poly (rA)11 was published by the laboratory of Dr. Kalle Gehring, McGill University, in collaboration with George Sheldrick, University of Göttingen, and Christopher WIlds, Concordia University. The paper appeared in the journal Angewandte Chemie International Edition under the title of "Structure of the Parallel Duplex of Poly (A) RNA: Evaluation of a 50 year-Old Prediction."
"After 50 years of study, the identification of a novel nucleic acid structure is very rare. So when we came across the unusual crystals of poly (rA), we jumped on it," said Dr. Gehring.
Gehring said identifying the double-helical RNA will have interesting applications for research in biological nanomaterials and supramolecular chemistry. Nucleic acids have astounding properties of self-recognition and their use as a building material opens new possibilities for the fabrication of bionanomachines – nanoscale devices created using synthetic biology.
Monday, August 26, 2013
Are black holes surrounded by walls of fire? Does this imply that one (or more) of our most cherished physical principles—and here I’m talking about biggies like quantum theory, the conservation of information or Einstein’s equivalence principle—is wrong? Any may our savior come in the form of wormholes? These are the questions consuming some of the world’s foremost theoretical particle physicists as they argue about potential solutions to what has become known as the “black hole firewall” problem—perhaps the most important paradox in physics since Stephen Hawking proposed his first black hole information paradox nearly four decades ago.
The black hole firewall paradox has caused no small amount of wonder and confusion amongst particle physicists. It appears as though one of our core beliefs about the universe is wrong: Either particles can be promiscuously entangled, leading to quantum disaster (basically no one takes this option seriously; quantum theory and the no-promiscuous-entanglement rule are far too well supported by decades of experimental evidence), or information is not conserved (another non-starter), or black holes have firewalls (even Polchinski considers this a reductio ad absurdum), or… we just don’t fully understand what’s really going on.
And so in an effort to sort the mess out, physicists gathered this week at the Kavli Institute for Theoretical Physics at UCSB to talk over the options. (They’ve been doing a great job uploading videos of all the talks, so if you’re interested in watching smart folks try to hash out knotty thought experiments in near-real time, you can follow along at home.) One of the most intriguing possibilities for a solution comes from Juan Maldacena and Leonard Susskind, building on the ideas of Mark Van Raamsdonk and Brian Swingle. Maldacena and Susskind posit that the solution to the firewall problem may come in the form of wormholes.
It makes you wonder if ALL entanglement isn't an example of wormholes, ahem, Einstein-Rosen Bridges attached to particles. Hence, the title.
The SY-7 is one of three Chinese satellites doing some very strange things in orbit
On July 29, a Chinese Long March-4C rocket blasted into space from the northern Taiyuan Space Center carrying three secretive, experimental satellites. Not really all that unusual by itself — a robotic arm reportedly on one of the satellites could be involved in testing for Beijing’s far-off space station program.
But once they were in orbit, the satellites began acting very, very strangely.
More precisely, one of the satellites, known as SY-7, was moving all over the place and was appearing to make close-in rendezvous’s with other satellites. It was so strange, space analysts wondered whether China was testing a new kind of space weapon — one that could intercept other satellites and more or less claw them to death.
It’s not as crazy as it sounds. The U.S. has experimented with anti-satellite weapons, and is even researching how to cannibalize satellites in orbit. China has even blown up one of its own satellites with a missile. That caused an international outcry considering the giant cloud of debris which has come close to imperiling space travel for a century.
In the four years since the Great Recession officially ended, the productivity of American workers — those lucky enough to have jobs — has risen smartly. But the United States still has two million fewer jobs than before the downturn, the unemployment rate is stuck at levels not seen since the early 1990s and the proportion of adults who are working is four percentage points off its peak in 2000.
This job drought has spurred pundits to wonder whether a profound employment sickness has overtaken us. And from there, it’s only a short leap to ask whether that illness isn’t productivity itself. Have we mechanized and computerized ourselves into obsolescence?
Are we in danger of losing the “race against the machine,” as the M.I.T. scholars Erik Brynjolfsson and Andrew McAfee argue in a recent book? Are we becoming enslaved to our “robot overlords,” as the journalist Kevin Drum warned in Mother Jones? Do “smart machines” threaten us with “long-term misery,” as the economists Jeffrey D. Sachs and Laurence J. Kotlikoff prophesied earlier this year? Have we reached “the end of labor,” as Noah Smith laments in The Atlantic?
Of course, anxiety, and even hysteria, about the adverse effects of technological change on employment have a venerable history. In the early 19th century a group of English textile artisans calling themselves the Luddites staged a machine-trashing rebellion. Their brashness earned them a place (rarely positive) in the lexicon, but they had legitimate reasons for concern.
Economists have historically rejected what we call the “lump of labor” fallacy: the supposition that an increase in labor productivity inevitably reduces employment because there is only a finite amount of work to do. While intuitively appealing, this idea is demonstrably false. In 1900, for example, 41 percent of the United States work force was in agriculture. By 2000, that share had fallen to 2 percent, after the Green Revolution transformed crop yields. But the employment-to-population ratio rose over the 20th century as women moved from home to market, and the unemployment rate fluctuated cyclically, with no long-term increase.
Labor-saving technological change necessarily displaces workers performing certain tasks — that’s where the gains in productivity come from — but over the long run, it generates new products and services that raise national income and increase the overall demand for labor. In 1900, no one could foresee that a century later, health care, finance, information technology, consumer electronics, hospitality, leisure and entertainment would employ far more workers than agriculture. Of course, as societies grow more prosperous, citizens often choose to work shorter days, take longer vacations and retire earlier — but that too is progress.
So if technological advances don’t threaten employment, does that mean workers have nothing to fear from “smart machines”? Actually, no — and here’s where the Luddites had a point. Although many 19th-century Britons benefited from the introduction of newer and better automated looms — unskilled laborers were hired as loom operators, and a growing middle class could now afford mass-produced fabrics — it’s unlikely that skilled textile workers benefited on the whole.
Fast-forward to the present. The multi-trillionfold decline in the cost of computing since the 1970s has created enormous incentives for employers to substitute increasingly cheap and capable computers for expensive labor. These rapid advances — which confront us daily as we check in at airports, order books online, pay bills on our banks’ Web sites or consult our smartphones for driving directions — have reawakened fears that workers will be displaced by machinery. Will this time be different?
Go read. The New Artisans is a concept which needs to be expanded on. I'll do that as my Fifth Crazy Thought, I think. However, I need to return to the Fourth Crazy Thought (I made a booboo and I'll do my mea culpa and I have been communicating with the principle investigator on a project which ran a simulation of a very large neural net recently on Riken).
As part of its second-quarter earnings announcement today, local transportation and delivery giant Uber announced its biggest bet on autonomous vehicles yet, saying it would purchase 2,500 driverless cars from Google. In addition, the two companies have agreed to a deal in which Uber will share data from its local transportation services with Google, which will use it to further improve its own autonomous car-routing algorithms.
Uber has committed to invest up to $375 million for a fleet of Google’s GX3200 vehicles, which are the company’s third generation of autonomous driving cars, but the first to be approved for commercial use in the U.S. The deal marks the largest single capital investment that Uber has made to date, and is also the first enterprise deal that Google has struck for its new line of driverless vehicles.
Origin and palaeoenvironmental significance of Lystrosaurus bonebeds in the earliest Triassic Karoo Basin, South Africa
1. Pia A. Viglietti (a)
2. Roger M.H. Smith (b)
3. John S. Compton (a)
a. Department of Geological Sciences, University of Cape Town, Private Bag X3, Rondebosch, 7701, (+ 27733760065)
b. Iziko South African Museum of Cape Town, P.O. Box 61, Cape Town, 8000 South Africa
Earth experienced its most devastating extinction event at the end of the Permian period 251 million years ago (Ma). Despite an estimated 75 to 90% loss of species globally in both marine and terrestrial realms across the Permian–Triassic Boundary (PTB), around 20% of the terrestrial tetrapod genera in southwestern Gondwana survived and were immediately joined by a number of immigrant taxa to occupy most of the vacant niches of the earliest Triassic. Preserved in the Karoo Basin of South Africa is an almost continuous stratigraphic record of terrestrial sedimentation through the PTB that hosts a fossil record of ecosystem collapse, survivorship and recovery. The adaptation of the mammal like reptiles (therapsids) of the Lystrosaurus Assemblage Zone to a highly seasonal, potentially drought prone semi-arid earliest Triassic Karoo Basin is associated with changes in modes of fossilisation. Isolated dicynodont skulls and postcranial elements are commonly found in the latest Permian. However, in the earliest Triassic the dicynodonts occur as articulated, curled-up skeletons and multi-individual monotaxic bonebeds. Lack of epiphyses and relatively small skull length confirm that the bonebeds comprise several subadult Lystrosaurus declivis (L. declivis) carcasses. No significant evidence for hydraulic bone concentration along with clusters of ribs in life position point to complete carcasses being present at the site of death, and suggest that animals behaviourally congregated before perishing together. The bonebeds are hosted by an 8 m thick horizon of floodplain mudrocks in the lower Katberg Formation named the Lystrosaurus abundant zone. The bonebed horizon is overlain by sand-filled mud cracks capped by coarse sediments indicative of rapid deposition during waning floods. Stable isotope analyses of pedogenic and early diagenetic calcite nodules in association with the bonebeds yield average δ13C values ranging from − 9.5 to − 5‰ and δ18O values of 13.5 to 16‰, respectively. These isotope values support a seasonally cold, semi-arid climate at high latitude (~ 55ºS). The presence of vertebrate burrow casts on bonebed horizons and evidence of shelter sharing suggests tetrapods were attempting to escape extreme climatic conditions. Aggregation behaviour of subadult Lystrosaurus during unusual cold snaps may best explain the origin of bonebed assemblages.
Age, Nd–Hf isotopes, and geochemistry of the Vijayan Complex of eastern and southern Sri Lanka: A Grenville-age magmatic arc of unknown derivation
1. A. Kröner (a, b)
2. Y. Rojas-Agramonte (a, b)
3. K.V.W. Kehelpannala (c)
4. T. Zack (a)
5. E. Hegner (d)
6. H.Y. Geng (e)
7. J. Wong (e)
8. M. Barth (a)
a. Institut für Geowissenschaften, Universität Mainz, 55099 Mainz, Germany
b. Beijing SHRIMP Centre, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China
c. Department of Geology, University of Botswana, Private Bag UB 00704, Gaborone, Botswana
d. Department für Geo- und Umweltwissenschaften, Universität München, Theresienstrasse 41, 80333 Munich, Germany
e. Department of Earth Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China
The ca. 1.0–1.1 Ga Vijayan Complex (VC) of eastern and southeastern Sri Lanka is one of three high-grade metamorphic terranes making up the basement of the island and is in tectonic contact with the adjacent, older Highland Complex. It consists predominantly of granitoid gneisses ranging in composition from diorite to leucogranite, with a distinct calc-alkaline geochemical signature, and is interpreted as a magmatic arc. Strong ductile deformation has obliterated almost all original intrusive relationships. High-grade metamorphism during the Pan-African event at ca. 610–520 Ma has produced widespread granulite-facies assemblages that are now largely retrogressed and were affected by extensive late metamorphic K-metasomatism. In southern Sri Lanka the Vijayan gneisses are tectonically interlayered with rocks of the Highland Complex in a so-called mixed zone. We report zircon ages, whole-rock Nd and Hf-in-zircon isotopic systematics and geochemical data for a large selection of Vijayan gneissses in order to better characterize this complex and its tectonic setting. The zircon ages are predominantly in the range 1100–1000 Ma with a few early Neoproterozoic intrusions, and identify the VC as a Grenville-age magmatic arc. Many zircons experienced minor to significant lead-loss at about 580 Ma. The Nd and Hf isotopic data confirm a generally primitive origin for most Vijayan gneisses, but significant variations in both isotopic systems argue for source heterogeneities and the possible involvement of minor amounts of older continental material in their genesis. Immobile trace and rare earth element distributions favour an origin of the gneiss protoliths through melting at relatively shallow depth, and the chemical variation from diorite and tonalite via granodiorite to granite in the VC can be explained by increasing fractionation of plagioclase and biotite, accompanied by amphibole and accessory phases. The VC may be comparable, in some respect, to the composition and evolution of the Kohistan Arc in Pakistan. The unique composition, age and isotopic characteristics of the VC find no convincing counterpart in other fragments of the Gondwana supercontinent, and its origin therefore remains exotic and enigmatic.
We had some coffee and yummies while we looked at car magazines. He's SERIOUSLY into cars. Like I was for dinosaurs. I try my best to be supportive. He may be my son (lizard chaser!) and his grandfather's grandson (seriously athletic and very strong hands compared to very long skinny fingers), but this car thing is something all his own.
Sunday, August 25, 2013
Geopolitical analysts continue to question the U.S. commitment to rebalancing its forces in the Asia-Pacific region to reinvigorate the nation’s presence there.
The recent skepticism echoes similar concerns raised by Asia-based analysts about just how strong a military player the U.S. intends to be in the Asia-Pacific region. The doubts are surfacing amid reports of major military buildups by American partners in the region.
Indeed, while all the attention seems focused on China’s intentions and impacts in the region, the Asian giant will not be the biggest variable in geopolitical security in that part of the world, argues Randal Shriver, president and CEO of the Project 2049 Institute think tank. Shriver is also founding partner of Armitage International and a senior associate at the Center for Strategic and International Studies.
“It is not China,” Shriver said Aug. 22 during an event hosted by the Atlantic Council’s Brent Scowcroft Center on International Security. “It is the United States. And if the U.S. is not up to the task, that throws uncertainty into that region.”
The problem is that, despite President Barack Obama’s touted Asia-Pacific rebalancing, there continues to be no “go-to” person in the administration for Asia — nor does the administration seem to still have passion for the effort, he says. There seems to be little concrete to back up the plans.
Saturday, August 24, 2013
Exospheric O2 densities at Europa during different orbital phases
1. C. Plainaki (a)
2. A. Milillo (a)
3. A. Mura (a)
4. J. Saur (b)
5. S. Orsini (a)
6. S. Massetti (a)
a. IAPS Roma - Istituto di Astrofisica e Planetologia Spaziali di Roma, Via del Fosso del Cavaliere, 00133 Roma, Italy
b. Universität zu Köln, Institut für Geophysik und Meteorologie, Albertus-Magnus-Platz, D-50923 Köln, Germany
Europa's exosphere is a mixture of different species among which sputtered H2O and H2 dominate in the highest altitudes and O2, formed mainly by radiolysis of ice and subsequent release of the produced molecules, prevails at lower altitudes. Europa's O2 exosphere has been demonstrated through both observation and simulation-based techniques to be spatially non-uniform. In the present study we investigate Europa's exospheric O2 characteristics under the external conditions that are likely in the Jupiter's magnetospheric environment, applying the Europa Global model of Exospheric Outgoing Neutrals (EGEON, Plainaki et al., 2012) for different configurations between the positions of Europa, Jupiter and the Sun. We demonstrate for the first time that the spatial distribution of Europa's exosphere is explicitly time-variable due to the time-varying relative orientations of solar illumination and the incident plasma direction. We show that the O2 release efficiency depends both on solar illumination and plasma impact direction. The modeled densities at different orbital phases of Europa are compared, a posteriori, with the analysis results from two observations in order to validate the model. Using the outputs of EGEON we also calculate the supply of neutral oxygen atoms of exospheric origin to Europa's neutral cloud.
Friday, August 23, 2013
A highlight of the MAKS air show, which opens at Zhukovsky Airport near Moscow next week, is likely to be the demonstration of the Sukhoi T-50 PAK FA (Perspektivny Aviatsionny Kompleks Frontovoy Aviatsii—Future Tactical Air System) fighter.
The T-50 appeared at MAKS two years ago, but is now flying with updated control laws that expand its flight envelope. (The program had flown fewer than 100 test sorties between its January 2010 maiden flight and its MAKS debut.) Recent videos show the aircraft performing what appear to be sustained-altitude flat rotation maneuvers and high-angle-of-attack turns similar to those demonstrated at the Paris air show by the Su-35S. Four T-50 prototypes have now flown and a fifth is expected to fly by the end of the year. The first state acceptance trials are due to start in 2014, United Aircraft Corporation President Mikhail Pogosyan said earlier this year, and production should start in 2015.
Russian President Vladimir Putin has said that production aircraft will enter service in 2016. However, since the aircraft has yet to fly with its definitive engine, this most likely indicates that the Russian air force is reverting to Soviet-era practice by equipping an operational test unit with interim-standard aircraft while development of the objective system is completed.
Many details of the fighter's equipment and armament remain classified or unpublished. However, in recent months the Sukhoi design bureau has obtained several patents relating to the T-50, including the rationale behind the stealth fighter's configuration.
Gypsum, Opal, and Fluvial Channels within a Trough of Noctis Labyrinthus, Mars: Implications for Aqueous Activity during the Late Hesperian to Amazonian
1. Catherine M. Weitz (a)
2. Janice L. Bishop (b)
3. John A. Grant (c)
a. Planetary Science Institute, 1700 E Fort Lowell, Suite 106, Tucson, AZ 85719
b. SETI/NASA AMES, 515 N. Whisman Rd., Mountain View, CA 94043
c. Smithsonian Institution, National Air and Space Museum, CEPS, MRC 315, Independence Ave. at 6th St SW, Washington, DC 20013
We investigate in detail the morphology, mineralogy, and stratigraphy of light-toned deposits within one trough of Noctis Labyrinthus, centered at −6.8°N, 261.1°E. CRISM spectra taken from light-toned layered deposits in the northern portion of the trough exhibit absorptions around 1.41, 1.92 and 2.21 μm, consistent with mixtures of opal and Al-clays that are exposed beneath younger lava flows and between high-standing mesas of chaotic terrain. In the southern portion of the trough, opal occurs as a patchy surficial deposit along the southeastern lower wall. Gypsum appears to be present in the southern portion of the trough where spectra show triplet absorptions at 1.44, 1.48, and 1.54 μm, and additional absorptions at 1.20, 1.74, 1.95, 2.22, 2.27, and 2.49 μm. The gypsum-bearing materials consist of one to several beds that typically fill low-lying regions, including valleys. A bright mound on the trough floor exhibits spectral features at 1.43, 1.92 and 2.43 µm, characteristic of polyhydrated sulfates. The bright mound appears distinct in morphology from chaotic terrain, and along its base are exposures of gypsum-bearing materials.
Fluvial channels in the southwestern portion of the trough incise surface slopes at 4–6° and lack obvious sources. The channels display first and second order tributaries arranged in a parallel pattern and may have formed by localized surface discharge from melting snow and/or ice. Both opal and gypsum occur in close proximity in the southwestern region of the trough, but gypsum is found alone in the southeast and opal in association with Al-clays is found to the northwest. We do not believe gypsum and opal formed coevally because they are not always found together, they require different aqueous conditions (i.e., opaline deposits require high silica availability while the gypsum deposits require high Ca availability in solution), and they appear at stratigraphically distinct levels. Although we identified evidence for fluvial landforms within the trough, cross-cutting relations indicate their incision post-dates deposition of the opal and pre-dates deposition of the gypsum. Hence, several periods of aqueous activity and alteration likely occurred within the trough from the Late Hesperian into the Amazonian that reflect favorable localized conditions within the Noctis Labyrinthus region and may be contemporaneous with late aqueous activity occurring elsewhere on Mars.
For the thousands of secondary school students who take Japan’s university entrance exams each year, test days are long-dreaded nightmares of jitters and sweaty palms. But the newest test taker can be counted on to keep its cool: AIs don’t sweat.Not yet, but soon...
At Japan’s National Institute of Informatics (NII), in Tokyo, a research team is trying to create an artificial intelligence program that has enough smarts to pass Japan’s most rigorous entrance exams. The AI will start by taking the standardized test administered to all secondary school students; once it masters that test, it will move on to the more difficult University of Tokyo exam.
“Passing the exam is not really an important research issue, but setting a concrete goal is useful,” says Noriko Arai, the team leader and a professor at NII. And by having the AI answer real questions from the exams, “we can compare the current state-of-the-art AI technology with 18-year-old students,” she says. The latest results show that her protégé is coming along well in subjects like history and reading comprehension.
The project began in 2011, when the director of NII challenged his professors to come up with a problem that was “stupendously big and stupendously difficult,” as Arai describes it, but could be easily understood by the general public. The University of Tokyo, known locally as Todai, has a legendarily difficult entrance exam, and the problem came to Arai in an elevator: “Could a robot get into the Todai?” she wondered. Thus the Todai Robot was born.
By 2016, the team hopes its AI will achieve a high score on the national standardized test, which includes multiple-choice questions in subjects such as physics and world history and requires students to solve math problems. But the machine-learning and natural-language-processing tools Arai’s team is developing for that test won’t prepare it for the Todai exam, which includes written essays. The team hopes the AI will pass the Todai exam by 2021, although they don’t yet know how it will accomplish that goal. “The generation of text from information has not been studied very much,” says NII associate professor Yusuke Miyao, another member of the team.