The U.S. Department of Energy has declassified documents related to a Cold War hearing for the man who directed the Manhattan Project that developed atomic bombs and was later accused of having communist sympathies.
The department last week released transcripts of the 1950s hearings on the security clearance of J. Robert Oppenheimer, providing more insight into the previously secret world that surrounded development of the atomic bomb.
The US Army could fund development of rotorcraft technology offered by two companies not selected to build demonstrator aircraft under the Pentagon's Joint Multi-Role Technology Demonstrator (JMR-TD) programme, officials announced on 3 October.
The army selected a Sikorsky-Boeing team and Bell Helicopter in August to build rotorcraft for JMR-TD with partial government funding,
However, in a 3 October statement, the Army said AVX Aircraft Company and Karem Aircraft Inc, two smaller companies, "also offer technologies and configurations of interest", adding it would "seek to continue technology development efforts with those teams based on resources and opportunities".
Temperature-dependent remineralization and carbon cycling in the warm Eocene oceans
Authors:
John et al
Abstract:
Metabolic rates in heterotrophic bacteria are more sensitive to temperature than rates of primary production (e.g., López-Urrutia et al., 2006; Regaudie-de-Gioux and Duarte, 2012). Consequently, faster bacterial respiration rates in a warmer ocean may result in more efficient remineralization of sinking organic matter higher in the water column, with implications for carbon and nutrient cycling during warm climate states. This is supported by a series of reconstructed δ13CDIC: depth profiles based on well-preserved planktonic foraminifera assemblages from Tanzania from the warm Eocene epoch (55.5–33.7 Ma) when global surface and deep ocean temperatures exceeded those of the modern day (John et al., 2013). These results indicate relatively sharp δ13CDIC gradients in the upper water column which supports the hypothesis that high metabolic rates in warm Eocene oceans led to more efficient recycling of organic matter and reduced burial rates of organic carbon (Olivarez Lyle and Lyle, 2006). Shallower remineralization depths would also cause an upward displacement and intensification of the oxygen minimum zone which is consistent with evidence for a pelagic ecosystem that was focused in a narrow depth range near the surface during the warm early and middle Eocene. Here we use the Earth System model, cGENIE, that incorporates a new temperature dependence of remineralization rates to illustrate the potential effects of temperature on particulate organic carbon fluxes and hence vertical δ13CDIC gradients. Modeled δ13CDIC vertical profiles off the coast of Tanzania for the Eocene agree well with the reconstructed δ13CDIC profiles, supporting our interpretations based on temperature-dependent remineralization.
A new type of jarosite deposit on Mars: Evidence for past glaciation in Valles Marineris?
Authors:
Cull et al
Abstract:
Acid-sulfate minerals such as jarosite are often used as indicators of environmental conditions on Mars. These minerals form in a diverse set of environments on Earth; however, all known Martian jarosite deposits are most likely evaporative, from evaporation of either groundwater or ponded water. Here, we use the Compact Reconnaissance Imaging Spectrometer for Mars and High-Resolution Imaging Science Experiment to report a new jarosite deposit along the southern wall of Ius Chasma. The morphology and geologic context of the Ius deposit are unique on Mars, and difficult to explain with an evaporative or groundwater mechanism. We propose instead that it was deposited along the margins of a past glacier. Such acid-ice interactions would be similar to those reported along the margins of Svalbard glaciers (arctic Norway), and would represent a new style of acid-sulfate formation on Mars.
Pleistocene cave art from Sulawesi, Indonesia
Authors:
Aubert et al
Abstract:
Archaeologists have long been puzzled by the appearance in Europe ~40–35 thousand years (kyr) ago of a rich corpus of sophisticated artworks, including parietal art (that is, paintings, drawings and engravings on immobile rock surfaces) and portable art (for example, carved figurines) and the absence or scarcity of equivalent, well-dated evidence elsewhere, especially along early human migration routes in South Asia and the Far East, including Wallacea and Australia where modern humans (Homo sapiens) were established by 50 kyr ago. Here, using uranium-series dating of coralloid speleothems directly associated with 12 human hand stencils and two figurative animal depictions from seven cave sites in the Maros karsts of Sulawesi, we show that rock art traditions on this Indonesian island are at least compatible in age with the oldest European art11. The earliest dated image from Maros, with a minimum age of 39.9 kyr, is now the oldest known hand stencil in the world. In addition, a painting of a babirusa (‘pig-deer’) made at least 35.4 kyr ago is among the earliest dated figurative depictions worldwide, if not the earliest one. Among the implications, it can now be demonstrated that humans were producing rock art by ~40 kyr ago at opposite ends of the Pleistocene Eurasian world.
How the largest animals to have ever walked the Earth fed, and how this allowed them to live alongside one another in prehistoric ecosystems is the subject of new research from the University of Bristol and the Natural History Museum, London.
The sauropods – large, long-necked plant-eating dinosaurs such as Diplodocus and Brachiosaurus – dominated the land between 210 and 65 million years ago. They were the largest land animals of all time, with the biggest weighing 80 tonnes (more than 11 elephants) and would have needed vast amounts of food.
Despite this, multiple sauropod species often lived alongside each other. The most notable example is the community of the Late Jurassic Morrison Formation, a distinctive sequence of sedimentary rock in the western United States from which over 10 species of sauropod are known.
How so many giant herbivores could have coexisted has long been a mystery: even the highly diverse faunas seen in modern Africa only support one truly gigantic species, the elephant. This is made even more puzzling by the harsh, semi-arid environment of the Morrison Formation during the Jurassic, which would have limited plant growth.
A study conducted by David Button, a PhD student in Bristol's School of Earth Sciences and the Natural History Museum, and colleagues used a novel combination of approaches to investigate this problem.
Although sauropods were gigantic, their heads were comparatively very small and so how they ingested enough food has puzzled many scientists. The researchers focussed on the skull and jaws of sauropods, using a variety of biomechanical techniques to investigate how they functioned and what this would mean for sauropod ecology.
Using CT scans, the researchers digitally reconstructed the skulls of the sauropods Camarasaurus and Diplodocus, along with the jaw and neck muscles of both species from the traces left on the bones where these muscles were attached in life. These two species are very common in the Morrison Formation, and are known to have widely co-existed. From this data, a biomechanical computer model of the skull of Camarasaurus was built using Finite Element Analysis (FEA), a modelling technique often employed in engineering and design to calculate stress and strain distribution in complex shapes. This model was then compared to a pre-existing model of Diplodocus in order to investigate how the dinosaurs fed.
David Button said: "Our results show that although neither could chew, the skulls of both dinosaurs were sophisticated cropping tools. Camarasaurus had a robust skull and strong bite, which would have allowed it to feed on tough leaves and branches. Meanwhile, the weaker bite and more delicate skull of Diplodocus would have restricted it to softer foods like ferns. However, Diplodocus could also have used its strong neck muscles to help it detach plant material through movements of the head. This indicates differences in diet between the two dinosaurs, which would have allowed them to coexist."
The researchers also used a series of biomechanical measurements from other sauropod species to calculate the functional disparity in their skulls and jaws and found that other Morrison Formation sauropods were also highly varied in feeding adaptations, suggesting different diets.
Co-author, Professor Emily Rayfield of the University of Bristol said: "In modern animal communities differences in diet such as this – termed 'dietary niche partitioning' – allow multiple similar species to coexist by reducing competition for food. Although, dietary niche partitioning has been suspected between Morrison Formation sauropods based on their structural features and patterns of tooth-wear, this is the first study to provide strong, numerical, biomechanical evidence for its presence in this fossil community."
A newly described dinosaur, whose fossils are some of the first to be unearthed in Venezuela, turns out to be the close, relatively small kin of creatures that later evolved into multiton meat eaters such as Allosaurus and Tyrannosaurus rex. The creature, and another dinosaur whose fossils were found nearby and reported just 2 months ago, are filling in gaps in the fossil record and revealing new insights into dinosaur evolution in the wake of a mass extinction that happened about 201 million years ago.
The new species, dubbed Tachiraptor admirabilis, is a predator that gets part of its name from the Venezuelan state of Táchira, where the fossils were found. Only two bones of the ancient species have been unearthed, says Max Langer, a vertebrate paleontologist at the University of São Paulo in Brazil. Nevertheless, those bits (each from a different individual, and one of them not even a complete bone) tell scientists a lot, Langer notes.
Neoarchean to Paleoproterozoic continental growth in the southeastern margin of the North China Craton: Geochemical, zircon U-Pb and Hf isotope evidence from the Huoqiu complex
Authors:
Liu et al
Abstract:
The Huoqiu complex in the southeastern margin of the North China Craton (NCC) is dominated by Neoarchean grey gneisses, amphibolites and voluminous metasediments. Here we report the occurrence of Neoarchean to Paleoproterozoic rocks from drill core samples. The gneisses are similar to TTG (tonalite-trondhjemite-granodiorite) in composition and show close spatial association with amphibolites. Geochemical characteristics such as high Sr/Y and (La/Yb)N with steep REE patterns and trace element modeling suggest that these rocks were generated by partial melting of hydrous meta-basalts (amphibolites) at the base of a thickened mafic continental crust, leaving a rutile-bearing eclogite residue. LA-MC-ICP-MS U-Pb age data from magmatic zircon grains show protolith emplacement ages of 2.76-2.71 Ga. Subsequently, widespread migmatization took place at 1.91-1.82 Ga, generating voluminous migmatites and high-K granites. Hf isotopic compositions of zircon grains from the amphibolite and gneiss show εHf(t) values of 2.4-15.5 and − 3.0-1.5, respectively. The tDM2(Hf) model ages of the gneisses range from 2.87 to 3.14 Ga, and are identical to the tDM1(Hf) ages of amphibolites (2.84-3.16 Ga) within analytical uncertainty, suggesting that the gneisses formed by partial melting of amphibolite, and attest to large-scale reworking of the ancient continental crust during Neoarchean. The zircon grains from the granites define two groups with regard to their Hf isotopic composition. The older group (1916 ± 42 Ma) has εHf(t) values and tDM2(Hf) ages of − 10.5-2.4 and 2.40-3.20 Ga, respectively, whereas the younger one (1823 ± 41 Ma) shows a large variation in εHf(t) values ranging from − 18.1 to 12.5, with tDM2(Hf) model ages of 1.70-3.59 Ga. A couple of zircon grains from the younger group display consistent U-Pb ages and tDM2, indicating accretion of juvenile crust from depleted mantle sources during 1.82 to 1.91 Ga. However, the dominant Hf isotope features are consistent with the reworking of preexisting continental crust. We therefore infer that only limited accretion of juvenile crust occurred during this time, and that the Paleoproterozoic (1.82 to 1.91 Ga) tectonics in the southeastern margin of the NCC witnessed extensive reworking of older continental crust.
Efforts to reduce China's carbon dioxide emissions are being offset by the country's rampant economic growth, according to new research from the University of East Anglia (UEA).
Research published today in Nature Climate Change reveals how carbon efficiency has improved in nearly all Chinese provinces. But the country's economic boom has simultaneously led to a growth in CO2-emitting activities such as mining, metal smelting and coal-fired electricity generation – negating any gains.
According to the study, China, the world's largest producer of CO2 emissions, increased its carbon intensity by 3 per cent during a period of unprecedented economic growth. This was despite its pledge to reduce carbon intensity by up to 45 per cent by 2020 (relative to the 2005 level).
The findings are part of a seven-year study conducted by Prof Dabo Guan of UEA's School of International Development, and an international research team. The research was partly funded by the Economic and Social Research Council's (ESRC) Centre for Climate Change Economics and Policy (CCCEP) at the University of Leeds.
Wide variations were reported between China's 30 provinces. The less economically advantaged province of Guizhou achieved a 98 per cent gain in carbon efficiency, but concurrent production increases led to a 125 per cent efficiency loss. Consequently, the net carbon efficiency of the province fell by 27 per cent.
The most marked improvements occurred in the economically advanced coastal areas and the heavily industrialised inland regions.
While the implementation of new, less wasteful technologies helped most provinces boost their carbon efficiency, China's emissions-intensive capital projects offset those advances. For example, Inner Mongolia replaced many inefficient, carbon-intensive factories with large-scale modern facilities. This resulted in metal smelting and cement production increasing 14-fold between 2002-2009. As a consequence, the region experienced a 159 per cent efficiency improvement, but a 141 per cent increased scale of production meant the net efficiency gain was a comparatively modest 18 per cent.
Likewise, the carbon efficiency of China's coal-fired power plants improved by 10 per cent, while its production capacity more than doubled and its share in the total economy also increased. Other CO2-intensive industries showed similar trends.
In the past decade, China has maintained at least an 8 per cent annual GDP, propped up by the construction of railroads, highways, power grids and housing.
As China flexes its economic and military muscle, it's bumping elbows with Asia's other big and fast-growing power: India.
China's hunger for energy from the Middle East and resources from Africa brings it into the Indian Ocean. And some defense analysts in India are watching uneasily as China develops commercial ports in some of India's neighbor countries.
To understand India's concerns about China, it helps to remember that the two countries have a history of border disputes, and that they fought a brief but ferocious war over territory in 1962.
The head of U.S. Southern Command (SOUTHCOM) warned an Ebola outbreak in Central America or the Caribbean could trigger a mass migration to the U.S. of people fleeing the disease and implied established Central American illegal trafficking networks could introduce the infected into the U.S., during remarks at a Tuesday panel on security issue in the Western Hemisphere at the National Defense University.
“If it comes to the Western Hemisphere, the countries that we’re talking about have almost no ability to deal with it — particularly in Haiti and Central America,” SOUTHCOM Commander, Marine Gen. John F. Kelly, said in response to a question of his near term concerns in the region.
“It will make the 68,000 unaccompanied minors look like a small problem.”
An Ebola outbreak could encourage the poor and increasingly desperate populations in Central American countries — like Honduras, Guatemala and El Salvador — to leave in droves.
Back in 1997, physicists performed an extraordinary experiment that will be forever remembered by researchers and Star Trek fans alike. In this demonstration, the team transported photons from one point in the universe to another without sending them through the space in between — the first successful teleportation in history.
Teleportation is the transfer of the information that describes one object to another object elsewhere in space. In effect, this second object takes on the identity of the first. A more precise description of the team’s experiment with photons is that they transferred the quantum information that describes the polarisation state of one photon to another photon.
Still impressive but not quite the teleportation of the entire photon, which has multiple quantum properties. All of these need to be teleported to recreate it exactly.
Since then, this kind of teleportation has become routine in quantum optics labs all over the world but always with the same limitation. All these experiments involve the transfer of a single quantum property. Nobody has ever found a way to transmit the multiple quantum properties of a single object at the same time and thereby truly teleport it.
Until now. Today, Xi-Lin Wang and buddies at the University of Science and Technology of China in Hefei say they have done just that. The team have worked out how to teleport two quantum properties of a single photon to another photon at the same time — the first time this has ever been done. The work is an important stepping stone towards the ultimate goal of teleporting complex objects such as atoms and small molecules in their entirety.
While the practical challenges to a flying car are myriad, Slovakia's Aeromobil has steadily tried to overcome them. The company plans to unveil a production-ready version of its 'Flying Roadster' at the Pioneers Festival in Vienna, Austria on October 29.
The latest version—Aeromobil 3.0—is the result of continuous work by designer Štefan Klein that dates back to 1990. The Aeromobil 2.5 prototype made its first flight about one year ago.
A mocked-up set of busy streets in Ann Arbor, Michigan, will provide the sternest test yet for self-driving cars. Complex intersections, confusing lane markings, and busy construction crews will be used to gauge the aptitude of the latest automotive sensors and driving algorithms; mechanical pedestrians will even leap into the road from between parked cars so researchers can see if they trip up onboard safety systems.
The urban setting will be used to create situations that automated driving systems have struggled with, such as subtle driver-pedestrian interactions, unusual road surfaces, tunnels, and tree canopies, which can confuse sensors and obscure GPS signals.
“If you go out on the public streets you come up against rare events that are very challenging for sensors,” says Peter Sweatman, director of the University of Michigan’s Mobility Transformation Center, which is overseeing the project. “Having identified challenging scenarios, we need to re-create them in a highly repeatable way. We don’t want to be just driving around the public roads.”
A division of Textron Systems has won a $33.8 million Navy contract for an unmanned surface vehicle designed to sweep for acoustic and magnetic mines from the Littoral Combat Ship (LCS), company officials told USNI News last week.
The Unmanned Influence Sweep System (UISS previously known as the unmanned surface sweep system or USSS) is planned for the Mine Countermeasure (MCM) mission package planned for the Littoral Combat Ship (LCS).
The USV is designed to methodically sweep a patch of ocean towing a cable designed to trigger so-called influence mines — mines that activate when they detect sounds or magnetic signatures that correspond to those of a large ship.
“It’s a cable that you tow behind the USV,” Rear Adm. John Ailes, former program manager for LCS Mission Modules, told USNI News in 2013.
“It provided both acoustic — making noise like a ship — and the magnetic signature of a ship… It tells the mines, ‘I’m a ship, you should blow up’.”
UISS is based on Textron Systems Unmanned Systems’ Common Unmanned Surface Vessel (CUSV) the company has been testing for years, Bill Leonard of Textron Systems Unmanned Systems told USNI News.
“We started doing all of our lessons learned and came up with a fourth generation of our CUSV,” Leonard said.
“We made improvements to the hull form, we made the payload bay larger. Got a new propulsion system and just various other improvements that we’ve learned over the five or six years we’ve been doing this and that translate over to the Navy program.”
Textron now has two years to finalize the development of the UISS before a 2017 test of the MCM package.
Jakarta has reaffirmed its commitment to partnering with Seoul on the KFX indigenous fighter programme.
In a statement, Indonesia’s defence ministry says that six prototypes will be developed, of which one will be given to Indonesia for flight tests. In addition, it reiterates the role of Indonesian personnel in the programme, and that a final assembly line will eventually be located in Indonesia.
The statement follows the recent signing of an agreement between Jakarta and Seoul, which sets the stage for the KFX to move into the “engineering and manufacturing phase” – the second of the programme’s three phases.
The statement says the first phase, which covered technology development, was completed in December 2012. The third and final phase of the programme covers the development of production capabilities.
The Paleocene-Eocene Thermal Maximum: How much carbon is enough?
Authors:
Meissner et al
Abstract:
The Paleocene-Eocene Thermal Maximum (PETM), ~55.53 million years before present, was an abrupt warming event that involved profound changes in the carbon cycle and led to major perturbations of marine and terrestrial ecosystems. The PETM was triggered by the release of a massive amount of carbon, and thus the event provides an analogue for future climate and environmental changes given current anthropogenic CO2 emissions. Previous attempts to constrain the amount of carbon released have produced widely diverging results, between 2000 and 10000 gigatonnes carbon (GtC). Here we use the UVic Earth System Climate Model in conjunction with a recently published compilation of PETM temperatures [14] to constrain the initial atmospheric CO2 concentration as well as the total mass of carbon released during the event. Thirty-six simulations were initialized with varying ocean alkalinity, river runoff, and ocean sediment cover. Simulating various combinations of pre-PETM CO2 levels (840, 1680, and 2520 ppm) and total carbon releases (3000, 4500, 7000, and 10000 GtC), we find that both the 840 ppm plus 7000 GtC and 1680 ppm plus 7000–10000 GtC scenarios agree best with temperature reconstructions. Bottom waters outside the Arctic and North Atlantic Oceans remain well oxygenated in all of our simulations. While the recovery time and rates are highly dependent on ocean alkalinity and sediment cover, the maximum temperature anomaly, used here to constrain the amount of carbon released, is less dependent on this slow acting feedback.
Radar Investigations of Apollinaris Mons on Mars: Exploring the Origin of the Fan Deposits
Authors:
El-Maarry et al
Abstract:
Apollinaris Mons is an isolated volcano on Mars straddling the boundary between the southern highlands and the northern plains. One of its most distinctive features is its massive fan-shaped deposit that extends from a breach on its summit to distances of more than 150 km and drapes its entire southern flank. The composition and formation mechanism of these deposits remains controversial. We investigate the radar properties of the fan deposits (FD) of Apollinaris Mons using low-frequency sounding radar data in combination with high-resolution images and crater-size frequency analysis to constrain their inner shape and bulk composition. Our analysis indicates that the FD attains an irregular thickness and is gradually thinner towards their lateral margins. The crater-size frequency analysis shows that they may have undergone repeated resurfacing, which is suggestive of long-term evolution. Our analysis of Shallow Radar (SHARAD) radargrams traversing different sections of the FD reveals multiple and different subsurface interfaces among the radargrams crossing the thinnest part, which suggests a layered and complex inner shape. Our estimates for the bulk real part of the dielectric constant of the FD ranges from 3 to 5, which is consistent with an icy-silicate mixture or pyroclastic composition. Therefore, we conclude that lahars or pyroclastic flows are the most likely mechanism that created the FD, yet we cannot rule out additional contributions from lava flows. A combination of multiple processes is also possible since the deposits appear to have been modified by fluvial processes at a later stage of their formation.
The Middle Pleistocene handaxe site of Shuangshu in the Danjiangkou Reservoir Region, central China
Authors:
Li et al
Abstract:
The presence of Acheulean tool types (e.g. handaxes and cleavers) in East Asia has recently attracted considerable attention. They challenge the long lasting concept that the Early Palaeolithic in East Asia is characterized only by Mode 1 technology, and they reflect the diversity and complexity of Palaeolithic culture during hundreds of thousands of years. In this paper, we present a detailed technological analysis of the in situ artifact assemblage at the Shuangshu site (Danjiangkou Reservoir Region, central China), as well as intra- and inter-regional comparisons of some characteristic traits used to test the difference between handaxes in the East and the West. The results show that there are two reduction sequences taking place. One is expressed in the predominant use of quartz in the production the small-to-medium sized artifacts, which is an expedient technology that dominates the whole assemblage, and the other is represented by the predominant use of quartz phyllite and trachyte in the production of Large Cutting Tools (LCTs). The latter displays the technical criteria characteristic of Acheulean technology, although its origins are much debated. In addition, the number of LCTs and total artifacts is generally low for the size of the excavation area, which probably is a result of relatively small population size and the high mobility of hominids. The thickness of handaxes has been shown not to be a reliable variable in demonstrating the difference between the East and the West.
Species Richness and Evidence of Random Patterns in Assemblages of South American Titanosauria during the Late Cretaceous (Campanian–Maastrichtian)
Authors:
Silva Viera et al
Abstract:
The Titanosauria were much diversified during the Late Cretaceous, but paleobiological information concerning these sauropods continues to be scarce and no studies have been conducted utilizing modern methods of community analysis to infer possible structural patterns of extinct assemblages. The present study sought to estimate species richness and to investigate the existence of structures in assemblages of the South American Titanosauria during the Late Cretaceous. Estimates of species richness were made utilizing a nonparametric estimator and null models of species co-occurrences and overlapping body sizes were applied to determine the occurrence of structuring in this assemblages. The high estimate of species richness (n = 57) may have been influenced by ecological processes associated with extinction events of sauropod groups and with the structures of the habitats that provided abundant support to the maintenance of large numbers of species. The pseudocommunity analysis did not differ from that expected by chance, indicating the lack of structure in these assemblages. It is possible that these processes originated from phylogenetic inertia, associated with the occurrence of stabilized selection. Additionally, stochastic extinction events and historical factors may also have influenced the formation of the titanosaurian assemblages, in detriment to ecological factors during the Late Cretaceous. However, diagenetic and biostratinomic processes, influenced by the nature of the sedimentary paleoenvironment, could have rendered a random arrangement that would make assemblage structure undetectable.
Fluid-assisted interaction of peraluminous metapelites with trondhjemitic magma within the Petronella shear-zone, Limpopo Complex, South Africa
Authors:
Safonov et al
Abstract:
The principal problem concerning the evolution of Precambrian granulite complexes located between granite-greenstone cratons is their interaction with the underthrusted greenstone belts during exhumation from the lower crust. Besides evidence for pervasive and localized fluid fluxes arising from devolatilization of the greenschist and amphibolite-facies rocks in the course of their burial underneath the granulites, this interaction might also be expressed in formation of diverse magmas of granitic, trondhjemitic and granodioritic composition. We present results of a petrological, fluid inclusion and thermobarometric study of interaction between fluidized trondhjemitic magma and peraluminous metapelitic granulites associated with the regional high-grade Petronella shear zone located in the Southern Marginal Zone (SMZ) of the Limpopo Granulite Complex (South Africa). The hot (T ∼ 1000 °C) trondhjemitic magma, which, presumably, originated from partial melting of a basaltic (amphibolite) material at the base of the granulite complex or at the top of the underthrusted greenstone blocks, intruded granulites at P ∼ 8.0–9.5 kbar (24–28 km depth) at 2.667 ± 0.9 Ga during the exhumation of the SMZ. The magma heated and assimilated orthopyroxene-cordierite metapelites and dragged them to a depth of 18–20 km (6.3–6.5 kbar). The magma was heterogeneously saturated with MgO, FeO, Al2O3 by the dissolved metapelites. This process provoked crystallization of several garnet generations from the trondhjemitic melt. Various mineral assemblages included in the different generations of garnet allowed application of TWQ method combined with PERPLE_X pseudo sections to trace sub-isobaric cooling of the magma from T ∼ 900–600 °C at 5.5–6.5 kbar. The isobaric cooling also affected the associated metapelites. Fluid inclusions trapped in garnet and quartz in the trondhjemite show that the magma transported carbonic fluid with densities corresponding to the late stages of magma cooling (600–650 °C and 5.5–6.5 kbar). Carbonic fluids coexisted with aqueous-salt fluids (preserved as inclusions with salinity up to 20.58 wt.% NaCl eq.). These low water activity fluids (aH2O less than 0.3)(aH2O less than 0.3) bearing Na, K and Ca salts, being exsolved from the magma on cooling and solidification, provoked formation of complex Na-gedrite + biotite + sillimanite + quartz ± staurolite ± plagioclase-bearing assemblages after cordierite in metapelites at temperatures 630–570 °C and pressures 5.5–6.5 kbar. These data provide evidence that hot trondhjemitic melts played a critical role in the exhumation of granulites onto the adjacent granite-greenstone craton. The trondhjemite transferred heat from the lower to the middle crust and transported large volumes of external aqueous-carbonic-salt fluids that participated in the rehydration of a significant portion of the SMZ.
An international research team's field work, drilling and measuring melt rates and ice sheet movement in Greenland is showing that things are, in fact, more complicated than we thought.
"Although the Greenland Ice Sheet initially speeds up each summer in its slow-motion race to the sea, the network of meltwater channels beneath the sheet is not necessarily forming the slushy racetrack that had been previously considered," said Matthew Hoffman, a Los Alamos National Laboratory scientist on the project.
A high-profile paper appearing in Nature this week notes that observations of moulins (vertical conduits connecting water on top of the glacier down to the bed of the ice sheet) and boreholes in Greenland show that subglacial channels ameliorate the speedup caused by water delivery to the base of the ice sheet in the short term. By mid summer, however, the channels stabilize and are unable to grow any larger. In a previous paper appearing in Science, researchers had posited that the undersheet channels were not even a consideration in Greenland, but as happens in the science world, more data fills in the complex mosaic of facts and clarifies the evolution of the meltwater flow rates over the seasons.
In reality, these two papers are not inconsistent - they are studying different places at different times - and they both are consistent in that channelization is less important than previously assumed, said Hoffman.
After buyers snapped up $7.8m worth of bitcoins that were selling for $300 each on exchange Bitstamp on Monday, bitcoin’s price appears to have found a hard floor in what has been a largely unpredictable trading period recently.
On Sunday, bitcoin’s price dropped through the 18-month average purchase price of $337.60, signalling uncertainty to many traders in the market. Then, in the early hours of the Asian morning on Monday, a sell order of 26,000 BTC at $300 that was placed on exchange Bitstamp brought a temporary halt to the volatile price and narrowed bid-ask spreads between the four exchanges in CoinDesk’s Bitcoin Price Index (BPI).
By the time of the European morning however, buyers had snapped up the entire order and the BPI jumped up into the low-to-mid-$320s.
“When the sell order for 26,000 BTC came onto Bitstamp, the price dropped from $317 to $300 in two seconds. I’ve just bought back in now that block has been lifted,” said Adam O’Brien, CEO of BTC Solutions, a Canada-based provider of ATM exchanges and leveraged trading services for bitcoin.
Gartner sees things like robots and drones replacing a third of all workers by 2025, and whether you want to believe it or not, is entirely your business.
This is Gartner being provocative, as it is typically is, at the start of its major U.S. conference, the Symposium/ITxpo.
Take drones, for instance.
"One day, a drone may be your eyes and ears," said Peter Sondergaard, Gartner's research director. In five years, drones will be a standard part of operations in many industries, used in agriculture, geographical surveys and oil and gas pipeline inspections.
"Drones are just one of many kinds of emerging technologies that extend well beyond the traditional information technology world -- these are smart machines," said Sondergaard.
Smart machines are an emerging "super class" of technologies that perform a wide variety of work, both the physical and the intellectual kind, said Sondergaard. Machines, for instance, have been grading multiple choice for years, but now they are grading essays and unstructured text.
This cognitive capability in software will extend to other areas, including financial analysis, medical diagnostics and data analytic jobs of all sorts, says Gartner.
"Knowledge work will be automated," said Sondergaard, as will physical jobs with the arrival of smart robots.
"Gartner predicts one in three jobs will be converted to software, robots and smart machines by 2025," said Sondergaard. "New digital businesses require less labor; machines will be make sense of data faster than humans can."
Ian Wright designed what may be one of the coolest street-legal cars of all time: the electric X1 looked like a Formula 1 racecar and went from zero to 60 in a breathtaking 2.9 seconds. Now, though, all Wright wants to talk about is trucks, especially the workaday delivery trucks and garbage trucks that ply city streets.
Why the excitement? Wright is the founder of Wrightspeed, a San Jose, CA-based startup that’s designed electric powertrains for medium- and heavy-duty trucks. “Garbage trucks are the perfect driving cycle for us: they get two or three miles per gallon, drive 130 miles a day with 1,000 hard stops that chew on the brakes. They’re just perfect,” he says.
Wright was among the founders of Tesla Motors. But despite his background in working on luxury performance cars, he’s come around to thinking that the biggest opportunity for electric vehicle disruption is where most of the fuel is burned—that is, big trucks. Cars may go through a few hundred gallons of gas a year but a commercial truck will burn through thousands of gallons or more. That means there’s a better financial incentive in terms of fuel savings to go electric.
Navy ships are at their most vulnerable when they’re resupplying in port or navigating narrow straits or rivers because they’re tricky to maneuver in tight quarters and vulnerable to attack. The attack 14 years ago on the USS Cole as it refueled while berthed in Yemen, an attack that killed 17 American sailors and reiterated the need to protect warships in port.
To counter asymmetric attacks—the 505-foot Cole was attacked by a small craft packed with explosives that ripped 40-foot gash in the destroyer—the Navy uses small patrol craft for close-quarters defense. And that means placing sailors in the line of fire. That got the Office of Naval Research into developing autonomous technology for small “swarmboats” that could be used for risky jobs.
These vessels would, much like the autonomous minesweepers the Army is testing, act as a force multiplier, allowing one sailor to do the work of several, from a safe location.
The technology, called Control Architecture for Robotic Agent Command and Sensing (CARACaS), is essentially an autopilot on steroids that can be installed on nearly any boat. During a test in August on the James River in Newport News, Virginia, Navy researchers used 13 rigid-hulled inflatable boats equipped with the technology to escort a “high-value” ship and swarm an “enemy” vessel. The boats decide on their own where to go, when to steer, and when to apply the throttle. A human operator, who can be in another ship, a helicopter, or well away from the action, uses a laptop to tell the swarmboats which craft are to be protected and which are to be attacked. Think of it as an officer giving his (robotic) sailors a mission—protect this guy, attack that one—and letting them determine how best to fulfill it.
The desertification of northern Africa may have started 7 million years ago, or more than twice as long ago as earlier estimates of the Sahara's age, climate simulations suggest. The findings also hint that this shift in climate would have been triggered by the gradual shrinking of the Tethys Sea, the predecessor of today’s Mediterranean.
The sands of the Sahara may seem timeless, but most geological data suggests that the world's largest non-polar desert formed between 2 million and 3 million years ago, about the same time as cycles of ice ages began plaguing the Northern Hemisphere.
Still, scientists have unearthed tantalizing clues that the Sahara may be much older than 3 million years old, says Zhongshi Zhang, a palaeoclimatologist at the Bjerknes Center for Climate Research in Bergen, Norway and a a co-author of the latest study, published on September 17 in Nature. Almost a decade ago, he notes, one team reported evidence of widespread dune deposits estimated to be 7 million years old in northern Chad.
Other analyses, including of long-term variations in the amounts of dust and pollen in sediments drilled from seafloors off northern Africa, chronicle extended dry spells in the region starting about 8 million years ago.
But it has been unclear what might have triggered the aridification, says Zhang. There were no major episodes of mountain formation that might have influenced climate in the region, he notes. Nor do his team's climate simulations suggest that long-term changes in Earth’s orbit or atmospheric concentrations of carbon dioxide are to blame.
Preservation of Ancient Ice at Pavonis and Arsia Mons: Tropical Mountain Glacier Deposits on Mars
Authors:
Head et al
Abstract:
Large tropical mountain glacier (TMG) deposits on the northwest flanks of the Tharsis Montes and Olympus Mons volcanoes are interpreted to be the record of ancient climates characteristic of Mars several hundred million years ago when planetary spin-axis obliquity was ~45°. During this era, polar volatiles (predominantly H2O) were mobilized and transferred equatorward, undergoing adiabatic cooling on the Tharsis volcano flanks, and precipitating snow and ice to form cold-based tropical mountain glaciers up to several kilometers in thickness. Subsequent climate change resulted in retreat, sublimation and collapse of the tropical mountain glaciers, leaving the three typical facies observed today: 1) Concentric ridges, the ridged facies, interpreted as drop moraines; 2) knobby facies, interpreted as debris-dominated sublimation residue; and 3) the smooth facies, interpreted as remnant alpine glacial deposits. Ring-mold craters (RMCs) are distinctive features formed by impacts into debris-covered ice. We describe a set of relatively fresh ring-mold craters superposed on the Arsia and Pavonis Mons TMG deposits; we interpret these to indicate that the impact events penetrated a veneer of sublimation lag and excavated buried remnant glacial ice, despite the lack of detection of buried ice by orbital radar instruments. The diameter distribution of the RMCs suggest that the remnant ice lies at a depth of at least 16 m. The TMG deposit ages suggest that these ice deposits date from a period in the range of 125–220 million years before the present; the remnant ice may thus preserve records of the ancient atmospheric gas content and microbiota, as is common in terrestrial glacial ice. Preservation of this ice and the lack of any associated fluvial features suggest that the post-glacial climate has been cold, and related surface temperatures have not been sufficient to bring the buried deposits to the melting point of water.
New findings by scientists at the University of California, Santa Cruz, suggest that an evolutionary arms race between rival elements within the genomes of primates drove the evolution of complex regulatory networks that orchestrate the activity of genes in every cell of our bodies.
The arms race is between mobile DNA sequences known as "retrotransposons" (a.k.a. "jumping genes") and the genes that have evolved to control them. The UC Santa Cruz researchers have, for the first time, identified genes in humans that make repressor proteins to shut down specific jumping genes. The researchers also traced the rapid evolution of the repressor genes in the primate lineage.
Their findings, published September 28 in Nature, show that over evolutionary time, primate genomes have undergone repeated episodes in which mutations in jumping genes allowed them to escape repression, which drove the evolution of new repressor genes, and so on. Furthermore, their findings suggest that repressor genes that originally evolved to shut down jumping genes have since come to play other regulatory roles in the genome.
"We have basically the same 20,000 protein-coding genes as a frog, yet our genome is much more complicated, with more layers of gene regulation. This study helps explain how that came about," said Sofie Salama, a research associate at the UC Santa Cruz Genomics Institute who led the study.
Retrotransposons are thought to be remnants of ancient viruses that infected early animals and inserted their genes into the genome long before humans evolved. Now they can only replicate themselves within the genome. Depending on where a new copy gets inserted into the genome, a jumping event can disrupt normal genes and cause disease. Often the effect is neutral, simply adding to the overall size of the genome. Very rarely the effect might be advantageous, because the added DNA can itself be a source of new regulatory elements that enhance gene expression. But the high probability of deleterious effects means natural selection favors the evolution of mechanisms to prevent jumping events.
Scientists estimate that jumping genes or "transposable elements" account for at least 50 percent of the human genome, and retrotransposons are by far the most common type.
"There have been successive waves of retrotransposon activity in primate evolution, when a transposable element changed to become expressed and replicated itself throughout the genome until something turned it off," Salama said. "We've discovered a major mechanism by which the genome is able to shut down these mobile DNA elements."
The repressors identified in the new study belong to a large family of proteins known as "KRAB zinc finger proteins." These are DNA-binding proteins that repress gene activity, and they constitute the largest family of gene-regulating proteins in mammals. The human genome has over 400 genes for KRAB zinc finger proteins, and about 170 of them have emerged since primates diverged from other mammals.
According to Salama, her team's findings support the idea that expansion of this family of repressor genes occurred in response to waves of retrotransposon activity. Because repression of a jumping gene also affects genes located near it on the chromosome, the researchers suspect that these repressors have been co-opted for other gene-regulatory functions, and that those other functions have persisted and evolved long after the jumping genes the repressors originally turned off have degraded due to the accumulation of random mutations.
"The way this type of repressor works, part of it binds to a specific DNA sequence and part of it binds other proteins to recruit a whole complex of proteins that creates a repressive landscape in the genome. This affects other nearby genes, so now you have a potential new layer of regulation available for further evolution," Salama said.
Enigmatic crocodyliforms from the early Miocene of Cuba
Authors:
Brochu et al
Abstract:
Early Miocene deposits from the Domo de Zaza locality, in the south-central Cuban province of Sancti Spiritus, preserve crocodyliform remains, including compressed serrated teeth closely resembling those of South American sebecids. Fragmentary cranial and mandibular material is more difficult to assess. Referral to any other post-Paleogene crocodyliform known from the Western Hemisphere can be ruled out, and phylogenetic analyses are unable to pinpoint its relationships. Similarities can be found with planocraniids, including ventrally oriented and mediolaterally expanded orbital surfaces, but the morphology of the quadrate is inconsistent with a planocraniid affinity. A sebecid in the Miocene of Cuba would be congruent with evidence from other vertebrates suggesting extensive dispersal between the Greater Antilles and South America during the Neogene, and it would be the first Neogene record of the group outside South America. The other crocodyliform may indicate the presence of an endemic West Indian lineage not closely related to any contemporaneous group. It is also consistent with extant Crocodylus arriving in the Neotropics within the past 5–10 million years.
Warm water benthic foraminifera document the Pennsylvanian–Permian warming and cooling events — The record from the Western Pangea tropical shelves
Author:
Davydov
Abstract:
Shallow warm water benthic foraminifera (SWWBF), including all larger fusulinids (symbiont-bearing benthic foraminifera), are among the best indicators of paleoclimate and paleogeography in the Carboniferous and Permian. The distribution of benthic foraminifera in space and time constrain important tectonic, paleogeographic and climatic events at a global scale. The North American shelves during Pennsylvanian and Permian time – though geographically within the tropical belt – are characterized by temperate environments with significantly lower foraminifera diversification and rare occurrences of warm water Tethyan forms, that are in general appear in the region as a migration entities. Such environments allow documentation of warming episodes associated with sudden immigration of warm water and exotic forms of SWWBF that evolved elsewhere into the area. First occurrence datum (FOD) of the forms exotic to North America during warming episodes are always delayed in respect of their First Appearance Datum (FAD) elsewhere. The time of delay and taxonomic diversity of fusulinids in North America shelves depended on the scale and intensity of the warming episodes. Cooling events, on the other hand, are associated with decreased taxonomic diversity and appearances of endemic forms characteristic only of temperate water provinces. The occurrence of these forms in Boreal and North American provinces appears to be isochronous, as their environments are uniform and induce their uniform and isochronous distribution. Several warming and cooling episodes during Pennsylvanian–Permian time are recognized. The differences between taxonomic variations in each event could potentially be used for provisional estimation of the degree of climatic change. A strong link between biotic and climatic events in North American province and the similarity of biotic changes in the North American and other provinces suggests that paleoclimatic events in North American province were controlled by global factors.
The burning heart - the Proterozoic geology and geological evolution of the west Musgrave Region, central Australia
Authors:
Howard et al
Abstract:
he Musgrave Province is one of the most geodynamically significant of Australia’s Proterozoic orogenic belts, lying at the intersection of the continent’s three cratonic elements – the West, North and South Australian Cratons. While remoteness and cultural sensitivity have slowed geological research into this region, recent collaborative programs in Western Australia (the west Musgrave Province) have done much to address this. This Focus Review provides a synthesis of this, and previous, work investigating the Mesoproterozoic to Neoproterozoic geological evolution of the province. The Musgrave Province is a Mesoproterozoic to Neoproterozoic belt dominated by granites formed and deformed during several major events. A cryptic juvenile basement is exposed mainly in the east Musgrave Province as c. 1600 – 1550 Ma orthogneiss and in the west Musgrave Province as isolated outcrops of granulite-facies metagranites of the c. 1575 Ma Warlawurru Supersuite. Zircon Hf-isotopic data suggest an earlier major juvenile crust-forming event at c. 1950–1900 Ma. There is, however, no evidence that the province evolved over Archean crust. The c. 1600 – 1550 Ma period probably involved evolution within a primitive arc setting, perhaps developed on c. 1950–1900 Ma oceanic or oceanic-arc crust. Voluminous calc-alkaline plutonism was accompanied by clastic and volcaniclastic basin formation during the 1345–1293 Ma Mount West Orogeny. This stage traced the evolution of a continental arc reflecting the final amalgamation of the combined North and West Australian Craton with the South Australian Craton. The intervening c. 1400 Ma primitive crust - the Madura Province – on which the proto-Musgrave Province had evolved, was consumed during amalgamation. The thickened crust resulting from this accretion was drastically thinned at the beginning of the c. 1220–1150 Ma Musgrave Orogeny as this central part of the new combined craton entered an extraordinary period of high heat flow characterised by c. 100 m.y. of ultrahigh-temperature metamorphism and high-temperature, anhydrous, alkali-calcic magmatism sourced from MASH chambers developed at the base of the thinned crust. The ridged cratonic architecture and a massive accumulation of high radiogenic heat producing granites within the mid crust perpetuated a thin crustal regime. Voluminous magmatism was again triggered during the c. 1090–1040 Ma Giles Event with the evolution of the magmatism-dominated, Ngaanyatjarra Rift. This event was likely initiated through renewed movement along translithospheric faults that intersected the thermally perturbed Musgrave Province, pinned at a cratonic junction. Mantle-derived bimodal magmatism extended more or less continuously for 50 m.y., producing one of the world’s largest layered mafic intrusions and supervolcano-sized additions of juvenile felsic crust, in the form of alkali-calcic to alkali, A-type, rhyolite deposits. Together, the Albany – Fraser Orogen, which developed over the southern margin of the West Australian Craton, and the Musgrave Province mark the preserved edge of the North and West Australian Craton. These two belts show remarkable chronological links between c. 1345 and 1150 Ma but contrasting histories before and after that period. Their period of shared evolution reflects collision and accretion of the South Australian Craton, but their tectonic setting and basement geology throughout that event were very different.
NEVER have Latin American leaders talked so much about regional integration as in the past decade. They have cooked up an alphabet soup of organisations, whose chefs hold non-stop summits even as trade among them grows only slowly. But three countries in the Americas have practised integration while eschewing much of the fanfare.
Under the North American Free-Trade Agreement (NAFTA), which came into effect in January 1994, the economies of Mexico and Canada have become ever more closely entwined with that of the United States. Trade between the three has more than tripled, to $1.1 trillion in 2013, and cross-border investment has risen fourfold. Many companies now operate on a North American basis.
Yet this economic entanglement has no match in politics and policy. The Security and Prosperity Partnership of North America, set up by George W. Bush in 2005 to deepen NAFTA, was quietly downgraded four years later to a regular meeting of the three countries’ leaders. An accompanying private-sector “competitiveness council” was disbanded.
Because NAFTA is falsely blamed in the United States for a net loss of manufacturing jobs, it is a subject that Barack Obama prefers not to mention. Stephen Harper, Canada’s Conservative prime minister, hews to his country’s close bilateral relationship with the United States. Mexico’s problems with organised crime, its reputation as a source of migrants (though few now cross the border) and the fear that it might provide an access route for terrorists (though it hasn’t) make closer trilateral ties politically toxic in the other two countries.
This neglect is a missed opportunity, according to a new report* by the Council on Foreign Relations, a New York think-tank. Drawn up by a group led by Robert Zoellick, a Republican former cabinet member, and General David Petraeus, a former commander of American forces in Iraq and Afghanistan, the report makes a passionate case for North America to switch from “an afterthought” to “a central priority for US policy”.
Discovery of a microcontinent (Gulden Draak Knoll) offshore Western Australia: Implications for East Gondwana reconstructions
Authors:
Gardner et al
Abstract:
Analysis of dredged samples from Gulden Draak Knoll demonstrate it is a submarine rifted continental fragment that lies at the boundary between the western Perth Abyssal Plain and Wharton Basin, Indian Ocean. The Knoll comprises a granulite facies basement, including pelitic paragneiss and mafic orthogneiss, with a Cambrian granite inferred to intrude the other rocks. Boulders and cobbles of felsic gneiss with Mesoproterozoic and Cambrian protolith ages were also sampled likely reflecting a complex basement to variable sedimentary and volcanic rocks. The U-Pb isotopic system in Archean and Mesoproterozoic zircon is significantly disturbed, reflecting Cambrian orogenesis that affected all samples. The protolith to garnet-sillimanite-biotite paragneiss has a maximum deposition age of 1163 ± 24 Ma and includes older detrital zircon grains with populations at c. 2.65 Ga and between 1.4-1.1 Ga. A younger population in this sample is interpreted as a mix of newly grown metamorphic zircon and isotopically reset zircon, implying the granulite facies metamorphism occurred at c. 511 ± 5 Ma. Protracted Cambrian orogenesis is indicated by a metamorphic age in the mafic orthogneiss of 530 ± 6 Ma and isotopic disturbance shortly following emplacement of granite (c. 540 Ma with zircon ages disturbed to 509 ± 7 Ma) and the protolith to the felsic orthogneiss (c. 528 Ma with zircon ages disturbed to 510 ± 3 Ma). Xenocrystic zircon grains in Cambrian rocks include Archean (c. 2839 ± 9 Ma) and Mesoproterozoic (1230–1370 Ma) populations also isotopically disturbed during Cambrian orogenesis. Igneous Cambrian zircon grains have less radiogenic Hf-isotope compositions (Hfi = 0.281821-0.281367) than Mesoproterozoic xenocrysts (Hfi = 0.282267-0.281993), indicating limited involvement of the Mesoproterozoic crust in granite production. A more likely source includes Archean crust represented by xenocrysts with Hfi = 0.281399-0.280863. The Gulden Draak Knoll is reconstructed in Gondwana (‘Leeuwin’ full-fit model) along strike of a major structure termed the Indo- Australo- Antarctic Suture (IAAS), recently mapped from geophysical interpretations in Wilkes Land, Antarctica. New isotopic data suggest basement rocks from the Gulden Draak Knoll have affinity to crust exposed either side of the IAAS. Determining if this structure is a suture zone sensu stricto remains to be tested.
Evidence for explosive silicic volcanism on the Moon from the extended distribution of thorium near the Compton-Belkovich Volcanic Complex
Authors:
Wilson et al
Abstract:
We reconstruct the abundance of thorium near the Compton-Belkovich Volcanic Complex on the Moon, using data from the Lunar Prospector Gamma Ray Spectrometer. We enhance the resolution via a pixon image reconstruction technique, and find that the thorium is distributed over a larger (40 km × 75 km) area than the (25 km × 35 km) high albedo region normally associated with Compton-Belkovich. Our reconstructions show that inside this region, the thorium concentration is 15 - 33 ppm. We also find additional thorium, spread up to 300 km eastward of the complex at ∼2 ppm. The thorium must have been deposited during the formation of the volcanic complex, because subsequent lateral transport mechanisms, such as small impacts, are unable to move sufficient material. The morphology of the feature is consistent with pyroclastic dispersal and we conclude that the present distribution of thorium was likely created by the explosive eruption of silicic magma.
Agricultural suitability and fertility in occidental piedmont of Calchaquíes Summits (Tucumán, Argentina)
Authors:
Vattuone et al
Abstract:
Our study area is located in the piedmont of Calchaquíes Summits (Tucumán Province, Northwest Argentina). The objectives of this paper are to improve the knowledge of Pre-Hispanic agricultural practices on landscape and soils, and to provide new knowledge about land fertility of agricultural areas, taking into account the environmental settings. Physical and chemical features, such as structure, texture, pH, calcium, organic and inorganic phosphorus, and available copper, manganese, and iron were taken into account. After photointerpretation and field surveys, two agricultural terraced geomorphological units were sampled. Samples were made in comparable off-site locations and the archaeological sites. After Principal Component Analysis, physicochemical analysis showed that texture is the most significant difference between the two archaeological sites. Agricultural practices introduced high chemical variations, despite the substantial differences between agricultural and off-site profiles. This is the first approach of this nature in Northwest Argentina.
Mosasaurids (Squamata) from the Maastrichtian Phosphates of Morocco: Biodiversity, palaeobiogeography and palaeoecology based on tooth morphoguilds
Authors:
Bardet et al
Abstract:
Mosasaurid squamates are the most numerically abundant, and taxonomically/ecologically diverse clade of marine amniotes represented in the Maastrichtian Phosphates of Morocco. With few exceptions, they are faunally typical of the Southern Mediterranean Tethys Margin (around palaeolatitude 25°N) and range from the base to the top of the stage. The Moroccan assemblages include at least 7 genera and 10 species representing a broad spectrum of sizes and morphologies that illustrate several ecological trends. Noteworthy is the predominance of Mosasaurinae which are widespread in contemporaneous outcrops worldwide and constitute 80% and 70% of the total genus/species number respectively. In contrast, Halisauromorpha and Russellosaurina (plioplatecarpines) are scarce and tylosaurines are presently unknown. All of the Moroccan mosasaurids exhibit characteristic tooth morphologies and can be placed into resource partitioning morphoguilds indicative of adaptations for piercing, crushing or cutting. Medium to large predators are found to distribute along the ‘Crush’-‘Cut’ axis of the morphoguild projection, and a new ‘Crush-Cut’ guild, previously unrecognised amongst Mesozoic marine amniotes, accommodates several Prognathodon species. Also of importance is the lack of mosasaurids along the ‘Pierce’-‘Crush’ axis, potentially inferring that these ecological niches were occupied by other marine vertebrates such as selachians and plesiosaurs. In addition, the relative abundance of mosasaurids throughout the Maastrichtian series of the Gantour Basin evidences direct ecological competition or predation phenomena.
Coprolites from the upper Osawa Formation (upper Spathian), northeastern Japan: Evidence for predation in a marine ecosystem 5 Myr after the end-Permian mass extinction
Authors:
Nakajima et al
Abstract:
Lower Triassic marine deposits, which can potentially provide important information on the diversity and trophic structure of marine ecosystems following the end-Permian mass extinction, are rarely exposed in the world. Given the sparse body fossil record from the Lower Triassic, non-body fossil evidences, such as trace fossils for example, may provide additional windows on fossil ecosystems. Herein, the authors recently found dark, amorphous lumps of various sizes, ranging from a few millimetres to approximately 7 cm in maximum dimension, from the offshore marine deposit of upper Osawa Formation (Spathian, Lower Triassic) in the South Kitakami Terrane of northeast Japan. Compared with the surrounding siliciclastic sediments, the lumps are rich in phosphate and organic carbon, and poor in silicates. Shape, mode of occurrence, bone inclusion and geochemical signatures of these lumps confirm that these are coprolites, produced not by benthic sediment feeders, but most likely by nektonic animals. Bone inclusion also suggests that carnivorous fish and/or marine reptiles, constituting the higher part of the food chain, produced at least a part of the specimens. Despite the low diversity of the known fossil vertebrates from the Osawa formation, coprolites first shed light on the predator–prey interactions in the marine ecosystem in South Kitakami Terrane 5 Myr after the end-Permian mass extinction.
Neoarchean disaggregation and reassembly of the Superior craton
Authors:
Bédard et al
Abstract:
The southern and western Superior craton of Canada (SWSC) is widely considered to be a tectonic collage accreted from north to south by multiple coeval subduction zones. We propose an alternative non-plate tectonic scenario where SWSC continental fragments are not exotic but derived by partial disaggregation of a heterogeneous older (Superior I) craton in response to a mantle overturn event that started at ca. 2780 Ma. During overturn, radial mantle outflow stretched and disaggregated the lithosphere to create the concentric Neoarchean fabric of the Superior craton, the southern part of which (SWSC) broke up into ribbon continents separated by oceanic tracts. Neoarchean calc-alkaline magmas record interaction between plume-related magma and older crust. A change in the mantle flow field at ca. 2720 Ma caused southward drift of the Northern Superior cratonic block as a result of mantle traction on its lithospheric keel, and SWSC terranes accreted to its leading edge.
A new model developed by researchers at the University of Cambridge has shown that despite its apparent stability, the massive ice sheet covering most of Greenland is more sensitive to climate change than earlier estimates have suggested, which would accelerate the rising sea levels that threaten coastal communities worldwide.
In addition to assessing the impact of the increasing levels of meltwater created and spilled into the ocean each year as the climate continues to warm, the new model also takes into account the role that the soft, spongy ground beneath the ice sheet plays in its changing dynamics. Details are published today (29 September) in the journal Nature Communications.
The Greenland Ice Sheet, which is the second-largest ice sheet in the world, covers 1.7 million square kilometres - an area roughly eight times the size of the United Kingdom - and contains enough ice to raise sea levels by more than seven metres if it were to be lost altogether.
Currently, due to surface melting alone, it is losing ice at a net annual rate of 200 gigatonnes, equating to 0.6 millimetres of sea level rise. A similarly large, but ultimately more uncertain source of sea level rise is tied to a net annual ice loss caused by increased movement of the ice sheet, which results in more ice being discharged into the ocean. Globally, sea levels are rising at three millimetres annually.
Large ice sheets such as in Greenland are far from stationary. Different parts of the ice often move at different speeds, causing ice to shear, a phenomenon known as ice flow.
"When these large ice sheets melt, whether that's due to seasonal change or a warming climate, they don't melt like an ice cube," said Dr Marion Bougamont of Cambridge's Scott Polar Research Institute, who led the research. "Instead, there are two sources of net ice loss: melting on the surface and increased flow of the ice itself, and there is a connection between these two mechanisms which we don't fully understand and isn't taken into account by standard ice sheet models."
Whereas other models of the Greenland Ice Sheet typically assume the ice slides over hard and impermeable bedrock - an assumption which is largely practical and based on lack of constraints - this study incorporates new evidence from ground-based surveys, which show soft and porous sediments at the bed of the ice sheet, more like the soft and muddy bottom of a lake than a sheet of solid rock. The new study specifically identifies the intake and temporal storage of water by weak sediment beneath the ice sheet as a crucial process in governing the ice flow.
Using a three-dimensional ice sheet model, together with an observational record of surface melting produced by collaborators at Aberystwyth University, Dr Bougamont and Dr Poul Christoffersen were able to accurately reproduce how the ice sheet's seasonal movement changes in response to the amount of surface meltwater being delivered to the ground below.
Lakes which form on the surfaces of glaciers, known as supraglacial lakes, are often created during the melt season, and typically last from early June to late August. Co-author Professor Alun Hubbard of Aberystwyth University studied these lakes and found that many empty in just a matter of hours, when hydrofracturing opens up water-filled crevasses, resulting in huge amounts of water entering and flooding the subglacial environment. In warmer years, these high-discharge drainage events are expected to become even more frequent.
"Not only is the ice sheet sensitive to a changing climate, but extreme meteorological events, such as heavy rainfall and heat waves, can also have a large effect on the rate of ice loss," said Dr Christoffersen. "The soft sediment gets weaker as it tries to soak up more water, making it less resistant, so that the ice above moves faster. The Greenland Ice Sheet is not nearly as stable as we think."
While complete loss of all ice in Greenland is judged to be extremely unlikely during this century, the record extent of surface melting in the past decade clearly shows that the ice sheet is responding to Earth's changing climate.
A Chinese military website, ostensibly sponsored by the People’s Liberation Army, quoting Sri Lanka media has reported that a Chinese Type 039 diesel-electric Song-class submarine along with Changxing Dao, a submarine support ship from the North Sea Fleet was sighted berthed alongside at the Colombo International Container Terminal. Although the pictures of the submarine and the support vessel together in the port have not been published either by the Sri Lankan or the Chinese media, it is believed that the submarine arrived in early September just before the Chinese President Xi Jingping’s visit to Sri Lanka. The report also states that the submarine was on a routine deployment and had stopped over for replenishment. Further, a Chinese naval flotilla would call at a Sri Lankan port later in October and November.
In the past, reports about the presence of Chinese submarines in the Indian Ocean have been announced in the media. For instance, the Indian media reported that a type-093 attack nuclear submarine was on deployment (December 2013 to February 2014) in the Indian Ocean and that the Chinese Ministry of National Defense (Foreign Affairs Office) had informed the Indian military attaché in Beijing of the submarine deployment to show ‘respect for India’. Apparently, the information of the deployment was also shared with the United States, Singapore, Indonesia, Pakistan and Russia.
WHEN Narendra Modi’s Bharatiya Janata Party won a thumping majority for its pro-growth promises in India’s elections in May, hopes swelled that the new government would adopt economic reforms that had proved beyond the brittle coalitions of the past. Yet in defiance of the maxim that the boldest steps are best taken early, Mr Modi has so far eschewed dramatic change.
Cuts to subsidies (such as on fuel and fertilisers), which cost 2.3% of GDP last year, have been deferred at least until a committee of experts produces a fresh report to add to the existing library of studies on the subject. There is no firm timetable for a national goods-and-services tax, which would boost GDP substantially by removing barriers to trade between India’s many states. Caps on foreign direct investment in many areas, including supermarkets, remain in place. Instead the government has taken a series of small steps, ginning up India’s sluggish bureaucracy, for instance. Is the chance to reshape India’s economy slipping away already?
Japan has chosen Fujitsu to help it regain the top spot in the global supercomputer race with an exascale machine, which at 1,000 petaflops would be about 30 times faster than the leading supercomputer today.
The electronics giant said Wednesday it will work with the Riken research center to come up with a basic design for the supercomputer that would succeed the K computer, a machine they co-developed that grabbed the No. 1 spot in June 2011.
Riken has a mandate from Japan’s Ministry of Education, Culture, Sports, Science and Technology (MEXT) to develop a next-generation supercomputer, and said it chose Fujitsu following an open bidding process to develop a “post-K supercomputer.”
Fujitsu will initially collaborate with Riken on a basic design, working towards beginning operation of the post-K computer supercomputer by April 2021.
The Riken Advanced Institute for Computational Science did not specify a performance speed or other characteristics of the machine, which it is calling the FLAGSHIP 2020 Project.
Helicopter-maker Sikorsky Aircraft Corp. unveiled its next-generation light-attack helicopter, the S-97 Raider, during a ceremony Thursday in Florida.
The coaxial design features counter-rotating rotor blades and a push propeller, among other innovations, that will allow it to fly much faster and farther than today’s choppers.
The Raider was designed to target a potentially $16 billion Army weapons program called the Armed Aerial Scout to develop a replacement for the OH-58 Kiowa Warrior, the smallest aircraft in the U.S. fleet. The service put the acquisition effort on hold due to automatic budget cuts.
