Sunday, May 31, 2015
Differential effects of fructose versus glucose on brain and appetitive responses to food cues and decisions for food rewards
Luo et al
Prior studies suggest that fructose compared with glucose may be a weaker suppressor of appetite, and neuroimaging research shows that food cues trigger greater brain reward responses in a fasted relative to a fed state. We sought to determine the effects of ingesting fructose versus glucose on brain, hormone, and appetitive responses to food cues and food-approach behavior. Twenty-four healthy volunteers underwent two functional magnetic resonance imaging (fMRI) sessions with ingestion of either fructose or glucose in a double-blinded, random-order cross-over design. fMRI was performed while participants viewed images of high-calorie foods and nonfood items using a block design. After each block, participants rated hunger and desire for food. Participants also performed a decision task in which they chose between immediate food rewards and delayed monetary bonuses. Hormones were measured at baseline and 30 and 60 min after drink ingestion. Ingestion of fructose relative to glucose resulted in smaller increases in plasma insulin levels and greater brain reactivity to food cues in the visual cortex (in whole-brain analysis) and left orbital frontal cortex (in region-of-interest analysis). Parallel to the neuroimaging findings, fructose versus glucose led to greater hunger and desire for food and a greater willingness to give up long-term monetary rewards to obtain immediate high-calorie foods. These findings suggest that ingestion of fructose relative to glucose results in greater activation of brain regions involved in attention and reward processing and may promote feeding behavior.
Epigenetic regulation of the nuclear-coded GCAT and SHMT2 genes confers human age-associated mitochondrial respiration defects
Hashizume et al
Age-associated accumulation of somatic mutations in mitochondrial DNA (mtDNA) has been proposed to be responsible for the age-associated mitochondrial respiration defects found in elderly human subjects. We carried out reprogramming of human fibroblast lines derived from elderly subjects by generating their induced pluripotent stem cells (iPSCs), and examined another possibility, namely that these aging phenotypes are controlled not by mutations but by epigenetic regulation. Here, we show that reprogramming of elderly fibroblasts restores age-associated mitochondrial respiration defects, indicating that these aging phenotypes are reversible and are similar to differentiation phenotypes in that both are controlled by epigenetic regulation, not by mutations in either the nuclear or the mitochondrial genome. Microarray screening revealed that epigenetic downregulation of the nuclear-coded GCAT gene, which is involved in glycine production in mitochondria, is partly responsible for these aging phenotypes. Treatment of elderly fibroblasts with glycine effectively prevented the expression of these aging phenotypes.
breathless pop sci write up.
Saturday, May 30, 2015
Cassini INMS measurements of Enceladus plume density
Perry et al
During six encounters between 2008 and 2013, the Cassini Ion and Neutral Mass Spectrometer (INMS) made in situ measurements deep within the Enceladus plumes. Throughout each encounter, those measurements contained density variations that reflected the nature of the source, particularly of the high-velocity jets. Since the dominant constituent of the vapor, H2O, interacted with the walls of the INMS inlet, we track changes in the external vapor density by using more-volatile species that responded promptly to those changes. However, the most-abundant volatiles, at 28 u and 44 u, behaved differently from each other in the plume. At least a portion of their differences may be attributed to mass-dependent thermal velocity that affects Mach number in the high-velocity jets. Variations between volatiles place an emphasis on modeling as a means to construct overall plume density from the volatile densities and to investigate the velocity, gas temperature, and location of the jets. Ice grains, entering the INMS aperture add complexity and uncertainty to the physical interpretation of the data because the grains modified the INMS measurements. A comparison of data from the last three encounters, E14, E17, and E18, are consistent with the VIMS observation of variability in jet production and a slower, more diffuse gas flux from the four sulci or tiger stripes. We provide and describe the INMS data, its processing, and its uncertainty.
It's a new weapon in the arsenal of cancer fighting treatments: utilizing genetically modified viruses to invade cancer cells and destroy them from the inside.
University of Louisville researcher Jason Chesney, M.D., Ph.D., deputy director of the James Graham Brown Cancer Center (JGBCC), and a team of international scientists found that stage IIIb to IV melanoma patients treated with a modified cold sore (herpes) virus had improved survival. The results of the findings were published recently in the Journal of Clinical Oncology.
UofL was one of the major sites for the phase III clinical trial involving 436 patients who received the viral immunotherapy, talimogene laherparepvec (T-VEC). Scientists genetically engineered the herpes simplex I virus to be non-pathogenic, cancer-killing and immune-stimulating. The modified herpes virus does not harm healthy cells, but replicates when injected into lesions or tumors, and then stimulates the body's immune system to fight the cancer.
"The results from this study are amazing," Chesney said. "Patients given T-VEC at an early stage survived about 20 months longer than patients given a different type of treatment. For some, the therapy has lengthened their survival by years. "
Extreme selective sweeps independently targeted the X chromosomes of the great apes
Nam et al
The unique inheritance pattern of the X chromosome exposes it to natural selection in a way that is different from that of the autosomes, potentially resulting in accelerated evolution. We perform a comparative analysis of X chromosome polymorphism in 10 great ape species, including humans. In most species, we identify striking megabase-wide regions, where nucleotide diversity is less than 20% of the chromosomal average. Such regions are found exclusively on the X chromosome. The regions overlap partially among species, suggesting that the underlying targets are partly shared among species. The regions have higher proportions of singleton SNPs, higher levels of population differentiation, and a higher nonsynonymous-to-synonymous substitution ratio than the rest of the X chromosome. We show that the extent to which diversity is reduced is incompatible with direct selection or the action of background selection and soft selective sweeps alone, and therefore, we suggest that very strong selective sweeps have independently targeted these specific regions in several species. The only genomic feature that we can identify as strongly associated with loss of diversity is the location of testis-expressed ampliconic genes, which also have reduced diversity around them. We hypothesize that these genes may be responsible for selective sweeps in the form of meiotic drive caused by an intragenomic conflict in male meiosis.
Friday, May 29, 2015
“In the next two years,” Army chief of staff Ray Odierno said today, the service could move out on four new combat vehicles and reboot its aging inventory for a new era of war. They range from a parachute-droppable light truck for Airborne soldiers to a scout car, a light tank, and a new infantry fighting vehicle to carry heavy troops into the teeth of enemy fire.
These projects are more incremental than revolutionary, more modest than ambitious, but they’re a step beyond the variants of 1980s-vintage vehicles the Army is currently procuring. They don’t attempt to transform the Army like the cancelled Future Combat System or the Reagan buildup’s famed “Big Five” — but they might just be the Feasible Four.
The biggest challenge is the IFV, sometimes also called the Future Fighting Vehicle. This machine would replace the Cold War mainstay of the armored force, the M2 Bradley, which FCS and the Ground Combat Vehicle programs both failed to do.
Lower Cretaceous deposit reveals first evidence of a post-wildfire debris flow in the Kirkwood Formation, Algoa Basin, Eastern Cape, South Africa
Muir et al
The Algoa Basin is an onshore rift basin filled by an Upper Mesozoic non-marine and shallow marine sedimentary sequence. The middle unit of this clastic succession is assigned to the Lower Cretaceous Kirkwood Formation, known to host a wealth of plant and animal fossils together with poorly documented lignites, amber and charcoal clasts. This study is motivated by the growing interest in the impact of wildfires on the palaeoenvironment during the high-oxygen, Cretaceous world. It has been hypothesised that frequent and severe Cretaceous wildfires triggered large-scale non-marine denudation events, altering the sedimentation dynamics and influencing the evolution of ecosystems. In order to investigate this phenomenon, charcoal-bearing sedimentary rocks and plant fossil assemblages of the Kirkwood Formation have been studied at the Bezuidenhouts River locality, ∼50 km north of Port Elizabeth (Eastern Cape, South Africa).
Detailed field observations of the sedimentary facies suggest that deposition occurred in a meandering fluvial environment with mature, vegetated floodplains. Depositional trends within a charcoal-rich bed (i.e., stratification, flattening and decrease in charcoal clast size down-current) indicate that a charcoal-rich debris flow, linked to a post-wildfire flood event, became diluted by fluvial flow. Palaeocurrent indicators (e.g., orientation of fossil logs) suggest unidirectional currents from SW to NE, which are somewhat inconsistent with the previously reported regional palaeocurrent directions in the Kirkwood Formation.
To gain insights into the fire-influenced dynamics of the Early Cretaceous ecosystems, the macro-plant fossil assemblages of the Kirkwood Formation were considered, with reference to the responses of modern plant analogues to wildfire. Of the plant orders reported from macrofossils of the Kirkwood Formation, the Cycadales, Pinales and Filicales, are known to have produced large woody or fibrous trunks and stems, or in the case of the Bennettitales more densely branched, divaricate architectures, and are likely to have provided the bulk of fuel for wildfires, with fern elements dominating groundcover niches. The particular role of these plants in the Early Cretaceous wildfire palaeoecology of the Algoa Basin is a topic for an ongoing study, but the Bezuidenhouts River locality appears to record the aftermath of a severe crownfire that led to mass tree mortality.
Redox conditions in the end-Early Triassic Panthalassa
Takahashi et al
This study focuses on an upper Lower Triassic (Spathian) to lowermost Middle Triassic (Anisian) section representing the central Panthalassic deep sea. Analysed organic carbon isotope ratio (δ13Corg) records from the section demonstrate that lower values in the Spathian increase by up to 6‰ at the Spathian–Anisian transition. This trend accords with the carbonate carbon isotope (δ13Ccarb) record from shallow-water carbonate sections. Most horizons during late Spathian–early Anisian show features of redox conditions of not fully oxic but dysoxic conditions, inferred from low Mn, U, V, Mo and euhedral pyrite-dominated occurrences. Conversely, in the end-Spathian black-coloured beds and underlying siliceous claystone beds, relatively higher concentrations of redox-sensitive elements such as U, V, Mo and abundant pyrite framboids are detected. As enrichment factors of redox-sensitive elements are not much higher than the typical anoxic–sulphidic trend and large pyrite framboids are found, these trends suggest suboxic rather than strong anoxic conditions. These oxygen-poor conditions coincide with carbon isotope minimum values at the late Spathian. At the same time, reducing seawater conditions have been also reported in from continental sections. These coincidences imply global environmental perturbations that may have been related to the delayed recovery of life after the end-Permian mass extinction.
That layout sure looks familiar
Thursday, May 28, 2015
“No less than 50 (Tu-160) aircraft over time will be purchased in order to cover the costs that will go into production,” Russian Air Force Commander Col.Gen. Viktor Bondarev said.
Today's industrial robots are remarkably efficient -- as long as they're in a controlled environment where everything is exactly where they expect it to be.
But put them in an unfamiliar setting, where they have to think for themselves, and their efficiency plummets. And the difficulty of on-the-fly motion planning increases exponentially with the number of robots involved. For even a simple collaborative task, a team of, say, three autonomous robots might have to think for several hours to come up with a plan of attack.
This week, at the Institute for Electrical and Electronics Engineers' International Conference on Robotics and Automation, a group of MIT researchers were nominated for two best-paper awards for a new algorithm that can significantly reduce robot teams' planning time. The plan the algorithm produces may not be perfectly efficient, but in many cases, the savings in planning time will more than offset the added execution time.
The researchers also tested the viability of their algorithm by using it to guide a crew of three robots in the assembly of a chair.
Given the aging of the population and the low birthrate both in Japan and elsewhere, healthcare professionals are in short supply and unevenly distributed, giving rise to a need for alternatives to humans for performing simple tasks. Although increasing numbers of medical institutions have introduced electronic medical records, a variety of issues remain unresolved, such as the inconvenience of data recording and the high costs associated with data input.
The use of robots to support medical care data management and the delivery of resources at the medical front--thus allowing humans to concentrate on those tasks requiring knowledge, skill, and experience--is expected to contribute to the enhancement of the quality of healthcare services.
Now, researchers at Toyohashi Tech have developed "Terapio," a next-generation robot that replaces the conventional medical cart used by healthcare staff during their rounds in a hospital.
Terapio assists staff in delivering resources and recording round information with its friendly communication abilities.
Terapio is an autonomous mobile robot that can track a person. It uses a differential-drive steering system to provide both quiet operation and smooth omnidirectional mobility. It recognizes its environment and autonomously tracks a specified human while avoiding obstacles. Using the Terapio's ring-shaped power-assist handle, an operator can control the robot accurately by applying a slight force. Terapio can also record patients' personal and vital signs data and also display data, such as the patient's health records. In terms of its exterior design and color scheme, Terapio is suitable for use in medical institutions. The touch panel on the top of Terapio is used for operating the robot and inputting/displaying round data. It is designed such that the operator and patient can recognize the robot's status and actions by expressions shown on the display that change according to the robot's operation mode, which are "power assist," "tracking," and "rounds."
Today’s agriculture has transformed into a high-tech enterprise that most 20th-century farmers might barely recognize.
After all, it was only around 100 years ago that farming in the US transitioned from animal power to combustion engines. Over the past 20 years the global positioning system (GPS), electronic sensors and other new tools have moved farming even further into a technological wonderland.
Beyond the now de rigeur air conditioning and stereo system, a modern large tractor’s enclosed cabin includes computer displays indicating machine performance, field position and operating characteristics of attached machinery like seed planters.
And as amazing as today’s technologies are, they’re just the beginning. Self-driving machinery and flying robots able to automatically survey and treat crops will become commonplace on farms that practice what’s come to be called precision agriculture.
Lay, brood, repeat: nest reuse and site fidelity in ecologic time for two Cretaceous troodontid dinosaurs
Varricchio et al
Whereas ‘biological site fidelity’ refers to the regular reuse of a favored locale (e.g., breeding ground or nest) by an individual animal, ‘paleontological site fidelity’ typically refers to repeated use of a nesting locality by a herd or species over geologic time scales. Two new Cretaceous specimens from the Two Medicine Formation of Montana, U.S.A., and the Liantoutang Formation of Zhejiang, China, each preserve two closely superimposed clutches of the egg form Prismatoolithus. These eggs belong to the Troodontidae, small theropod dinosaurs sharing a close ancestry with Aves. In both specimens, eggs of a lower clutch are truncated at a level below what would normally preserve in an undisturbed hatched clutch. These traces differ from past examples of dinosaur site fidelity in (1) the close or cross-cutting relationship of the clutches, (2) the precise overlay of clutch atop clutch, and (3) the implication of nest reuse and, thus, site fidelity on an ecologic rather than geologic scale and at approximately the individual rather than species level. Given the likely extended occupation of troodontid nesting sites by attending adults, factors such as nesting success and territoriality may, in addition to favorable substrates, have influenced the behaviors recorded by these specimens. The arrangements of eggs as clutches within the geologic record represent trace fossils. Thus, they record past in situ behavior, providing important insight into dinosaur nesting. In addition, they can serve as independent indicators of substrate conditions and sedimentary history, potentially refining our understanding of paleoenvironments.
A new Late Triassic traversodontid cynodont (Therapsida, Eucynodontia) from India
A large traversodontid cynodont Ruberodon roychowdhurii, gen et. sp. nov., is described from the Late Triassic Tiki Formation of the Rewa Gondwana Basin, India, based on an ontogenetic series of five partial lower jaws. Ruberodon is characterized by a robust and deep dentary symphysis, lower dental formula of i3-c1-pc9, procumbent and hypertrophied first lower incisor, a large canine, long diastema between the lower canine and first postcanine, and a high coronoid process at 60° to the horizontal tooth row. With growth, the symphyseal region became relatively more slender with lengthening of the diastema. Phylogenetic analysis based on 19 taxa and 35 craniodental characters places Ruberodon within the clade containing Gomphodontosuchus, Menadon, Protuberum, Scalenodontoides, and the multispecific Exaeretodon. The new genus forms a sister taxon to E. statisticae and is more advanced than E. riograndensis and E. argentinus based on the presence of a strong coronoid ridge anterior to the masseteric fossa. Based on its tetrapod assemblage, the Tiki Formation may be globally correlated with other formations such as the lower part of the Maleri Formation of India, the Isalo II Beds of Madagascar, and the upper part of the Santa Maria Formation of Brazil. An early Carnian age is proposed for the Tiki Formation.
Wednesday, May 27, 2015
MTA-B or not to be? Recycled bifaces and shifting hunting strategies at Le Moustier and their implication for the late Middle Palaeolithic in southwestern France
Gravina et al
Explaining late Middle Palaeolithic industrial variability remains a topic of great interest for researchers focusing on aspects of Neanderthal behavioural complexity and the so-called Middle-to-Upper Paleolithic ‘transition.’ Several sites in southwestern France figure prominently in these discussions, including the eponymous site of Le Moustier (Dordogne, France), one of the ‘key’ sequences used in larger anthropological models. Here we present a re-assessment of this important site based on a technological and taphonomic re-evaluation of previously studied collections combined with an analysis of unpublished archaeological material, which includes both lithic and faunal components. Our study produces a very different interpretation of the 'classic' Le Moustier sequence, challenging previous cultural attributions in a way that significantly impacts current debates surrounding the proposed Mousterian of Acheulean Tradition (MTA) – Châtelperronian affiliation. This new interpretation highlights independent changes in lithic technology and subsistence strategies that were previously undetected as well as a novel aspect of Neanderthal raw material use. Finally, we discuss how this new vision has important ramifications for broader issues connected to the definition of late Mousterian techno-complexes, such as the MTA, and the identification of relationships between technology, subsistence, and mobility strategies.
Isotopic evidence for Last Glacial climatic impacts on Neanderthal gazelle hunting territories at Amud Cave, Israel
Hartman et al
The Middle Paleolithic site of Amud Cave, Israel, was occupied by Neanderthals at two different time periods, evidenced by two chronologically and stratigraphically distinct depositional sub-units (B4 and B2/B1) during MIS 4 and MIS 3, respectively. The composition of both hunted large fauna and naturally-deposited micromammalian taxa is stable at the site over time, despite a ∼10 ky gap between the two occupation phases. However, while gazelle is the most ubiquitous hunted species throughout the occupation, isotopic analysis showed that there is a marked change in Neanderthal hunting ranges between the early (B4) and late (B2/B1) phases. Hunting ranges were reconstructed by comparing oxygen, carbon, and strontium isotopes from gazelle tooth enamel with modern isotope data from the Amud Cave region. This region is characterized by extensive topographic, lithological, and pedological heterogeneity. During the early occupation phase negative oxygen isotope values, low radiogenic 87Sr/86Sr ratios, and low Sr concentrations reveal restricted gazelle hunting in the high elevations west of Amud Cave. In the late occupation phase, hunting ranges became more diverse, but concentrate at low elevations closer to the site. Climatic proxies indicate that conditions were drier in the early occupation phase, which may have pushed gazelle populations into higher, more productive foraging areas. This study showed that Neanderthals adjusted their hunting territories considerably in relation to varying environmental conditions over the course of occupation in Amud Cave. It highlights the utility of multiple isotope analysis in enhancing the resolution of behavioral interpretations based on faunal remains and in reconstructing past hunting behaviors of Paleolithic hominins.
Lethal Interpersonal Violence in the Middle Pleistocene
Sala et al
Evidence of interpersonal violence has been documented previously in Pleistocene members of the genus Homo, but only very rarely has this been posited as the possible manner of death. Here we report the earliest evidence of lethal interpersonal violence in the hominin fossil record. Cranium 17 recovered from the Sima de los Huesos Middle Pleistocene site shows two clear perimortem depression fractures on the frontal bone, interpreted as being produced by two episodes of localized blunt force trauma. The type of injuries, their location, the strong similarity of the fractures in shape and size, and the different orientations and implied trajectories of the two fractures suggest they were produced with the same object in face-to-face interpersonal conflict. Given that either of the two traumatic events was likely lethal, the presence of multiple blows implies an intention to kill. This finding shows that the lethal interpersonal violence is an ancient human behavior and has important implications for the accumulation of bodies at the site, supporting an anthropic origin.
New species from Ethiopia further expands Middle Pliocene hominin diversity
Haile-Selassie et al
Middle Pliocene hominin species diversity has been a subject of debate over the past two decades, particularly after the naming of Australopithecus bahrelghazali and Kenyanthropus platyops in addition to the well-known species Australopithecus afarensis. Further analyses continue to support the proposal that several hominin species co-existed during this time period. Here we recognize a new hominin species (Australopithecus deyiremeda sp. nov.) from 3.3–3.5-million-year-old deposits in the Woranso–Mille study area, central Afar, Ethiopia. The new species from Woranso–Mille shows that there were at least two contemporaneous hominin species living in the Afar region of Ethiopia between 3.3 and 3.5 million years ago, and further confirms early hominin taxonomic diversity in eastern Africa during the Middle Pliocene epoch. The morphology of Au. deyiremeda also reinforces concerns related to dentognathic (that is, jaws and teeth) homoplasy in Plio–Pleistocene hominins, and shows that some dentognathic features traditionally associated with Paranthropus and Homo appeared in the fossil record earlier than previously thought.
Something is wrong in the world: a paleoanthropologist is using cladistics... also comes with an odd tree! At least compared to the traditional ones. Interesting that A sediba is not included.
Evidence of Reduced Export Productivity Supporting Living or Heterogeneous Ocean Hypotheses for KT/K-Pg mass Extinction
Evidence for reduced export productivity following the Cretaceous/Paleogene mass extinction
Esmeray-Senlet et al
The Cretaceous/Paleogene (K/Pg) mass extinction was associated with a collapse in the carbon isotopic (δ13C) gradient between planktonic and benthic foraminifera and a decrease in bulk carbonate δ13C values. These perturbations have been explained by several hypotheses: global collapse of primary productivity (Strangelove Ocean); greatly reduced export but not primary productivity (Living Ocean); little or no reduction in export productivity (Resilient Ocean); and geographic heterogeneity in the change of export productivity (Heterogeneous Ocean). We tested primary vs. export productivity changes in the paleoshelf of New Jersey, where δ13C values and organic carbon accumulation rates can distinguish among different ocean responses. On the shelf, the K/Pg boundary is associated with a ~2.5‰ δ13C decrease in bulk carbonate, a ~0.8‰ δ13C decrease in organic carbon, a collapse of the surface to bottom δ13C gradient, and a drop in organic carbon percentage. We interpret an early Danian ~1.0‰ planktonic foraminiferal δ13C gradient, a ~0.75‰ cross-shelf benthic foraminiferal δ13C gradient, and a drop in carbon accumulation rates to reflect the presence of active primary but limited export productivity, consistent with the Living Ocean hypothesis. We evaluated interbasinal deep-sea benthic foraminiferal δ13C gradients between the Pacific (Site 1210) and the Atlantic (Site 1262) oceans as a proxy for changes in export productivity. The interbasinal δ13C gradient was reduced after the mass extinction, suggesting a reduction in global export productivity. Although our data support the Living Ocean hypothesis, evidence from paleo-upwelling zones shows significant export productivity, indicating spatial heterogeneity in the wake of the K/Pg mass extinction (Heterogeneous Ocean).
Tuesday, May 26, 2015
Russia's space industry is in crisis caused by funding cuts, corruption and "moral decay," government officials said.
Billions of rubles have been lost in shady transactions. Construction projects are languishing. And important launches are failing.
In 2014 alone, federal space agency Roscosmos committed 92 billion rubles ($1.8 billion) worth of financial violations, according to Russia's public spending watchdog agency.
The head of the the audit office, Tatyana Golikova, said the amount of money allegedly misused initially shocked her.
"At first I could not believe my inspectors," Golikova told the Russian parliament during her annual presentation on Friday.
Germany and France are considering cooperation on developing a successor to the tank "Leopard 2." The current model has been in service since 1979, and aging Bundeswehr equipment is currently in stark focus.
The German Defense Ministry announced its plans for the "Leo 3" (as it's likely to be nicknamed in Germany) in a report on Friday to the Bundestag, which was obtained by multiple media outlets.
"Technologies and concepts will be investigated between 2015 and 2018 in joint studies also involving German industry," Markus Grübel, a deputy minister in the German Defense Ministry told his parliamentary colleagues. He cited the Leopard 2's long years of service as the reason that a new battle tank was required.
Note: The Germans and French are just getting started, so they are going to take a bit of time to sort out what they want (3 years). Then do the design.
The above is a fan art. Its amusingly close to what fans imagined the T-14 Armata was going to look like (but lacking a pair of crazy 20mm guns). The reality of the T-14 is rather different than the fan conception.
Could stegosaurs swim? Suggestive evidence from the Middle Jurassic tracksite of the Cleveland Basin, Yorkshire, UK
Romano et al
Ichnological evidence from the Ravenscar Group (Middle Jurassic) of Yorkshire reveals a distinctive type of swimming track associated with walking tracks of the ichnogenus Deltapodus. The morphology of the prints suggests that both track types were made by the same type of animal. Since Deltapodus is interpreted as having been made by a stegosaur, the associated footprints suggest that stegosaurs could swim. This has significant implications for their palaeobiology and dispersal. The swimming prints are assigned to the ichnotaxon Characichnos isp.
Giving a Crap: Understanding Polish Norian-Rhaetian Triassic PaleoEcologies Through Carnivore Coprolites
Coprolites of Late Triassic carnivorous vertebrates from Poland: An integrative approach
Zatoń et al
Vertebrate coprolites derived from Upper Triassic terrestrial deposits of southern Poland have been subjected to various analytical methods in order to retrieve information about their composition, producer’s diet and nature of the microscopic structures preserved in the groundmass. Morphologically, the coprolites have been classified into four morphotypes, of which only three were further analysed due to their good state of preservation. Their groundmass are composed of francolite, a carbonate-rich apatite, in which abundant coccoid structures are preserved. Based on various microscopic and organic geochemical techniques, they are interpreted as fossilized bacteria which could have mediated the phosphatization of the faeces. The thin sectioning revealed that the coprolites consist of those containing exclusively bone remains, and those preserving both bone and plant remains. Those coprolites preserving only vertebrate remains are suggestive for exclusive carnivorous diet of the producers. However, the interpretation of coprolites consisting of both vertebrate and plant remains is more debatable. Although they may attest to omnivory, it cannot be excluded that potential producers were carnivorous and occasionally ingested plants, or accidentally swallowed plant material during feeding. The latter may involve predation or scavenging upon other herbivorous animals. The potential producers may have been animals that foraged in or near aquatic habitats, such as semi-aquatic archosaurs and/or temnospondyls. This is supported by the presence of ostracode and other aquatic arthropod remains, and fish scales within the coprolites, as well as by the presence of specific biomarkers such as phytanic and pristanic acids, which are characteristic constituents of fish oil. The preservation of such labile organic compounds as sterols, palmitin, stearin or levoglucosan attests for rapid, microbially-mediated mineralization of the faeces at very early stages of diagenesis.
Monday, May 25, 2015
Early evolution of the Earth–Moon system with a fast-spinning Earth
Wisdom et al
The isotopic similarity of the Earth and Moon has motivated a recent investigation of the formation of the Moon with a fast-spinning Earth (Cuk, M., Stewart, S.T., . Science, doi:10.1126/science.1225542). Angular momentum was found to be drained from the system through a resonance between the Moon and Sun. They found a narrow range of parameters that gave results consistent with the current angular momentum of the Earth–Moon system. However, a tidal model was used that was described as approximating a constant Q tidal model, but it was not a constant Q model. Here we use a conventional constant Q tidal model to explore the process. We find that there is still a narrow range of parameters in which angular momentum is withdrawn from the system that corresponds roughly to the range found earlier, but the final angular momentum is too low to be consistent with the Earth–Moon system. Exploring a broader range of parameters we find a new phenomenon, not found in the earlier work, that extracts angular momentum from the Earth–Moon system over a broader range of parameters. The final angular momentum is more consistent with the actual angular momentum of the Earth–Moon system. We develop a simple model that exhibits the phenomenon.
Climate, dust, and fire across the Eocene-Oligocene transition, Patagonia
Selkin et al
The Eocene-Oligocene transition (EOT) is typically interpreted as a time of drastic global cooling and drying associated with massive growth of a glacial icecap in Antarctica and the shift to an "icehouse" climate. The effects of this transition on the terrestrial environments, floras, and faunas of the Southern Hemisphere, however, have been unclear. Here we document simultaneous changes in fire regime and plant community in Patagonia, Argentina. Decreases in the concentration of magnetite in loessites from the Eocene-Oligocene Vera Member of the Sarmiento Formation correlate with decreases in the fraction of burnt palm phytoliths as well as more consistently palm-dominated phytolith assemblages. Association of magnetite and burnt palm phytoliths suggests intense wildfires, which appear to have been suppressed for ∼200 k.y. shortly after the EOT. The disappearance of fire-related characteristics near the EOT is possible if changes in regional wind patterns—consistent with observed changes in sediment particle sizes—caused changes in seasonal precipitation. These results imply a more important role for fire in structuring Eocene-Oligocene landscapes than previously thought.
Oldest Pathology in a Tetrapod Bone Illuminates the Origin of Terrestrial Vertebrates
Bishop et al
The origin of terrestrial tetrapods was a key event in vertebrate evolution, yet how and when it occurred remains obscure, due to scarce fossil evidence. Here, we show that the study of palaeopathologies, such as broken and healed bones, can help elucidate poorly understood behavioural transitions such as this. Using high-resolution finite element analysis, we demonstrate that the oldest known broken tetrapod bone, a radius of the primitive stem tetrapod Ossinodus pueri from the mid-Viséan (333 million years ago) of Australia, fractured under a high-force, impact-type loading scenario. The nature of the fracture suggests that it most plausibly occurred during a fall on land. Augmenting this are new osteological observations, including a preferred directionality to the trabecular architecture of cancellous bone. Together, these results suggest that Ossinodus, one of the first large (>2m length) tetrapods, spent a significant proportion of its life on land. Our findings have important implications for understanding the temporal, biogeographical and physiological contexts under which terrestriality in vertebrates evolved. They push the date for the origin of terrestrial tetrapods further back into the Carboniferous by at least two million years. Moreover, they raise the possibility that terrestriality in vertebrates first evolved in large tetrapods in Gondwana rather than in small European forms, warranting a re-evaluation of this important evolutionary event.
Also with the evolution of tetrapods lecture from the Royal Tyrrell Museum's Lecture Series, some of the earliest tetrapods known, like Ichthyostega and Acanthostega, were secondarily aquatic...meaning, yes, they returned to the water, this makes for some interesting implications.
Sunday, May 24, 2015
For a full decade, Gudmundur Olafsson was unable to move his right ankle. That's because it wasn't there. Olafsson's amputated lower leg was the delayed casualty of an accident from his childhood in Iceland, when he was hit by an oil truck. “I lived in pain for 28 years,” says Olafsson. “After 50-plus operations, I had it off.” For years after the operation he wore a Proprio Foot, a prosthetic with a motorized, battery-powered ankle, sold by the Reykjavik-based company Ossur. The Proprio is essentially a wearable robot, with algorithms and sensors that automatically adjust the angle of the foot during different points in its wearer's stride. Olafsson's ankle moved on autopilot.
But 14 months ago Ossur upgraded his hardware. Now, at age 48, Olafsson can move his right ankle by thinking about it. When the electrical impulse from his brain reaches the base of his leg, a pair of sensors embedded in his muscle tissue connect the neural dots, and wirelessly transmit that signal to the Proprio Foot. Since the command reaches the foot before the wearer's residual muscles actually contract, there's no unnatural lag between intention and action. That makes Olafsson part of a highly exclusive club. Along with David Ingvasson, a fellow Ossur tester, he's one of the only people on the planet who owns a brain-controlled bionic limb. Ossur unveiled its implanted myoelectric sensor (IMES) technology today at an event in Copenhagen, and is now preparing large-scale clinical trials, in the hopes of reaching the market in three to five years.
“The first time, to be honest, I started to cry."
This is a bigger breakthrough in the field of robotics and advanced prosthetics than it might appear. Brain-controlled bionic limbs make headlines on a regular basis, with the implication that the science has been solved, and experimental systems are already transitioning to products. But most of those devices are confined to laboratories, and many require complex surgery, such as transplanting muscle tissue or implanting electrodes in a subject's brain. These devices look like the real thing in brief, sometimes compelling video clips. But so far, prosthetics that respond to thoughts are not so much a reality as a promise.
To Erik Trinkaus, the jaw of the oldest modern human found in Europe has always looked strange. Its huge wisdom teeth and hefty, buttressed lower jaw reminded him of Neandertals, and he argued that this fossil, 37,000 to 42,000 years old, was the product of generations of mixing between modern humans and our extinct cousins. “It wasn't a popular idea,” admits Trinkaus, a paleoanthropologist at Washington University in St. Louis. Other paleoanthropologists insisted that the young man whose remains were found in 2002 in Peştera cu Oase cave in Romania was just a chunky example of our own species.
Now, 15 years later, Trinkaus has been vindicated by ancient DNA. The young Oase man inherited as much as one-tenth of his DNA from a Neandertal ancestor, and that ancestor lived only 200 years or so previously, according to a talk this month at Cold Spring Harbor Laboratory in New York. “One of Oase's ancestors—its great-great-great-grandparent—is Neandertal,” reported Qiaomei Fu, a geneticist at the Chinese Academy of Sciences–Max Planck Society Joint Laboratory for Human Evolution in Beijing and a postdoc in the lab of population geneticist David Reich at Harvard Medical School. The finding is “important as the first direct evidence of a very recent admixture event in Europe,” says population geneticist Laurent Excoffier of the University of Bern.
Europe just after the arrival of modern humans has long seemed a likely setting for such close encounters, given that Neandertals and modern humans overlapped there about 45,000 to 39,000 years ago. But until now, ancient DNA pointed to a different time and place for such a liaison. By sequencing the genomes of fossil Neandertals and comparing them with today's human genomes, paleogeneticists had found that living Europeans and Asians—but not Africans—have inherited just 1% to 4% of their DNA from Neandertals. DNA from fossils of two modern humans from what is now Russia also suggested that their Neandertal heritage was faint (see http://scim.ag/RussDNA). So researchers proposed that modern humans and Neandertals had rare and relatively early encounters, perhaps in the Middle East, when moderns swept out of Africa 60,000 to 50,000 years ago.
The DNA from Oase 1, a lower jaw without a skull, complicates that picture, Fu reported at the Biology of Genomes meeting. Working in a team led by paleogeneticist Svante Pääbo of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, she and her colleagues captured 2.2 million base pairs of the fossil's DNA. Then, they sequenced 78,055 locations where the genomes of Neandertals and modern humans are known to differ. They found that the Oase man had far more Neandertal DNA—composing 4.8% to 11.3% of his genome—than either the ancient modern humans from Russia or living Europeans and Asians, Fu said.
What's more, the young man had inherited the Neandertal DNA in “large chunks,” including several segments more than 50 million base pairs long; one chunk spanned half the length of chromosome 12. Those unbroken stretches of Neandertal DNA suggest that the interbreeding must have been just four to six generations back. If the mixing had been more ancient, the long DNA segments would have been broken up by the reshuffling of chromosomes that takes place every generation. “This is quite amazing,” Fu said in her talk. “We're quite excited about that.”
If modern humans and Neandertals had several successful matings, why do living humans' genomes record only the earlier event?
Saturday, May 23, 2015
A large-scale anomaly in Enceladus’ microwave emission
Ries et al
The Cassini spacecraft flew by Enceladus on 6 November 2011, configured to acquire synthetic aperture RADAR imaging of most of the surface with the RADAR instrument. The pass also recorded microwave thermal emission from most of the surface. We report on global patterns of thermal emission at 2.17 cm based on this data set in the context of additional unresolved data both from the ground and from Cassini.
The observed thermal emission is consistent with dielectric constants of pure water or methane ice, but cannot discriminate between the two. The emissivity is similar to those of other icy satellites (≈≈0.7), consistent with volume scattering. The most intriguing result, however, is an anomaly in the thermal emission of Enceladus’ leading hemisphere. Evidence presented here suggests the anomaly is buried at depths on the order of a few meters. This anomaly is located in similar geographic location to anomalies previously detected with the CIRS and ISS instruments on Mimas, Tethys, and Dione (Howett, C.J.A. et al. . Icarus 216, 221–226; Howett, C.J.A. et al. . Icarus 221, 1084–1088; Howett, C.J.A. et al. . Icarus 241, 239–247; Schenk, P. et al. . Icarus 211, 740–757), but also corresponds with a geological feature on Enceladus’ leading terrain (Crow-Willard, E., Pappalardo, R.T. . Global geological mapping of Enceladus. In: EPSC-DPS Joint Meeting 2011. p. 635). Simple models show that the Crow-Willard and Pappalardo (Crow-Willard, E., Pappalardo, R.T. . Global geological mapping of Enceladus. In: EPSC-DPS Joint Meeting 2011. p. 635) model is a better fit to the data. Our best-supported hypothesis is that the leading hemisphere smooth terrain is young enough (<75 13="" 2="" a="" albedo="" an="" and="" anomaly="" at="" blockquote="" but="" cm.="" cm="" consistent="" depth="" electromagnetic="" gardening="" ground="" impact="" in="" increase="" is="" m="" measurements="" micrometeorite="" myr="" no="" observations="" of="" old="" picture="" radar="" region="" shallower="" show="" skin="" space="" than="" that="" the="" variation="" which="" with="">75>
Neural prosthetic devices implanted in the brain's movement center, the motor cortex, can allow patients with amputations or paralysis to control the movement of a robotic limb -- one that can be either connected to or separate from the patient's own limb. However, current neuroprosthetics produce motion that is delayed and jerky -- not the smooth and seemingly automatic gestures associated with natural movement. Now, by implanting neuroprosthetics in a part of the brain that controls not the movement directly but rather our intent to move, Caltech researchers have developed a way to produce more natural and fluid motions.
In a clinical trial, the Caltech team and colleagues from Keck Medicine of USC have successfully implanted just such a device in a patient with quadriplegia, giving him the ability to perform a fluid hand-shaking gesture and even play "rock, paper, scissors" using a separate robotic arm.
The results of the trial, led by principal investigator Richard Andersen, the James G. Boswell Professor of Neuroscience, and including Caltech lab members Tyson Aflalo, Spencer Kellis, Christian Klaes, Brian Lee, Ying Shi and Kelsie Pejsa, are published in the May 22 edition of the journal Science.
"When you move your arm, you really don't think about which muscles to activate and the details of the movement -- such as lift the arm, extend the arm, grasp the cup, close the hand around the cup, and so on. Instead, you think about the goal of the movement. For example, 'I want to pick up that cup of water,'" Andersen says. "So in this trial, we were successfully able to decode these actual intents, by asking the subject to simply imagine the movement as a whole, rather than breaking it down into a myriad components."
3.3-million-year-old stone tools from Lomekwi 3, West Turkana, Kenya
Harmand et al
Human evolutionary scholars have long supposed that the earliest stone tools were made by the genus Homo and that this technological development was directly linked to climate change and the spread of savannah grasslands. New fieldwork in West Turkana, Kenya, has identified evidence of much earlier hominin technological behaviour. We report the discovery of Lomekwi 3, a 3.3-million-year-old archaeological site where in situ stone artefacts occur in spatiotemporal association with Pliocene hominin fossils in a wooded palaeoenvironment. The Lomekwi 3 knappers, with a developing understanding of stone’s fracture properties, combined core reduction with battering activities. Given the implications of the Lomekwi 3 assemblage for models aiming to converge environmental change, hominin evolution and technological origins, we propose for it the name ‘Lomekwian’, which predates the Oldowan by 700,000 years and marks a new beginning to the known archaeological record.
Friday, May 22, 2015
Researchers at the University of California, Berkeley, have developed algorithms that enable robots to learn motor tasks through trial and error using a process that more closely approximates the way humans learn, marking a major milestone in the field of artificial intelligence.
They demonstrated their technique, a type of reinforcement learning, by having a robot complete various tasks -- putting a clothes hanger on a rack, assembling a toy plane, screwing a cap on a water bottle, and more -- without pre-programmed details about its surroundings.
"What we're reporting on here is a new approach to empowering a robot to learn," said Professor Pieter Abbeel in UC Berkeley's Department of Electrical Engineering and Computer Sciences. "The key is that when a robot is faced with something new, we won't have to reprogram it. The exact same software, which encodes how the robot can learn, was used to allow the robot to learn all the different tasks we gave it."
Robopoclypse now. ;)
Think it’s hard to find a place to charge your smartphone at the airport? Try finding a power outlet in the ocean.
Imagine you’re a robotic Navy mini-sub whose batteries are running low after a long mission monitoring, say, traffic around Chinese artificial islands in the South Pacific. Currently, you’d have to recharge at a land base or a surface ship. The former keeps you close to friendly shores while the latter gives away your presence. But if Navy program manager Mike Wardlaw makes it work, sometime in the early 2020s the Navy will start deploying unmanned, underwater pods where robots can recharge undetected — and securely upload the intelligence they’ve gathered to Navy networks.
Sec Mabus states UCLASS is a stepping stone to an unmanned fight and ought to be focused on ISR:
Ray Mabus likes robots. The Navy Secretary has declared the F-35 will be “the last manned strike fighter” the service ever buys and invested heavily in unmanned aircraft, boats, and submersibles. But Mabus has frustrated drone advocates on one major program: the Unmanned Carrier-Launched Surveillance and Strike (UCLASS) aircraft.
This morning, Mabus defended the Navy’s plans for a relatively modest UCLASS optimized for the “surveillance” aspect of its mission rather than the “strike” part — but he also promised UCLASS would be “the bridge” to a future unmanned strike plane, the one that replaces F-35. Given that the F-35 will be around for decades, however, this two-stage approach is unlikely to satisfy UCLASS critics like Senate ARmed Services chairman John McCain, House Seapower chairman Rep. Randy Forbes, and key players in the Pentagon itself, all of whom want a strike drone ASAP to deal with China.
Mabus said today at a DefenseOne leadership breakfast that “I’m for a full-up penetrating strike fighter” — eventually. “We see UCLASS as getting to that,” he said — but, he made clear, not as being that.
“For UCLASS…we ought to have endurance, we ought to have range, we ought to have payload,” he said, notably omitting stealth. “It should be an ISR [intelligence, surveillance, and reconnaissance] platform, it should be a refueling platform, but it also should be a strike platform [for] uncontested or minimally contested environments.”
In the longer term, he said, “it ought to be the bridge to a full-up strike fighter — an autonomous strike fighter — that [operates] in contested environments.”
Senator Forbes replies:
“Building ‘bridges’ sounds great, but at some point you need to cross them,” Rep. Forbes snapped in an email when I asked about Mabus’s comments. “While I understand the Navy’s desire to ‘crawl, walk, and run,’ I am concerned that in the race between anti-access and power projection capabilities, we are falling further and further behind. The carrier air wing is going to need a long-range, deep penetrating strike asset, and it is going to need it soon. Given that the UCLASS program is supposed to deliver its first operational aircraft to the fleet in 2022-23, I am concerned that the program seems to be driven by the needs of today and not those of tomorrow.”
The Sikorsky S-97 Raider hit an important milestone Friday with the successful first flight of its experimental rotorcraft.
The S-97, with two pilots, took off at the company's West Palm Beach, Fla., facility about 7 a.m. and performed all of its proscribed movements over roughly an hour. The flight test took on the basics — three take-offs and landings, and all cardinal movements at 10 knots — before more advanced tests over the year.
"This was, we feel, a really spectacular day for Sikorsky and aviation in general," said Mark Miller, Sikorsky's vice president for research and engineering. "It's not every day you have a first flight, and when you add on top of that a very differentiated, new and compelling product like the S-97 Raider, it makes it even more special.
"We're very excited, it was everything we wanted it to be and more, and it's the start of a new generation of helicopters and capabilities that we're really excited about," Miller said.
With the platform, Sikorsky officials said the company was firmly planting its flag for the Army's future vertical lift - light concept and armed aerial scout requirement. The S-97 was envisioned at one point as a contender replacement for the US Army's OH-58 Kiowa Scout, but the Army changed plans and scuttled the armed aerial scout for budgetary reasons, using the AH-64 Apache on an interim basis.
breaking my rules today...
The original snake ancestor was a nocturnal, stealth-hunting predator that had tiny hindlimbs with ankles and toes, according to research published in the open access journal BMC Evolutionary Biology.
The study, led by Yale University, USA, analyzed fossils, genes, and anatomy from 73 snake and lizard species, and suggests that snakes first evolved on land, not in the sea, which contributes to a longstanding debate. They most likely originated in the warm, forested ecosystems of the Southern Hemisphere around 128 million years ago.
Snakes show incredible diversity, with over 3,400 living species found in a wide range of habitats, such as land, water and in trees. But little is known about where and when they evolved, and how their original ancestor looked and behaved.
Lead author Allison Hsiang said: "While snake origins have been debated for a long time, this is the first time these hypotheses have been tested thoroughly using cutting-edge methods. By analyzing the genes, fossils and anatomy of 73 different snake and lizard species, both living and extinct, we've managed to generate the first comprehensive reconstruction of what the ancestral snake was like."
By identifying similarities and differences between species, the team constructed a large family tree and illustrated the major characteristics that have played out throughout snake evolutionary history.
Their results suggest that snakes originated on land, rather than in water, during the middle Early Cretaceous period (around 128.5 million years ago), and most likely came from the ancient supercontinent of Laurasia. This period coincides with the rapid appearance of many species of mammals and birds on Earth.
The ancestral snake likely possessed a pair of tiny hindlimbs, and targeted soft-bodied vertebrate and invertebrate prey that were relatively large in size compared to prey targeted by lizards at the time. While the snake was not limited to eating very small animals, it had not yet developed the ability to manipulate prey much larger than itself by using constriction as a form of attack, as seen in modern Boa constrictors.
While many ancestral reptiles were most active during the daytime (diurnal), the ancestral snake is thought to have been nocturnal. Diurnal habits later returned around 50-45 million years ago with the appearance of Colubroidea - the family of snakes that now make up over 85% of living snake species. As colder night time temperatures may have limited nocturnal activity, the researchers say that the success of Colubroidea may have been facilitated by the return of these diurnal habits.
ACADEMIC BUN FIGHT! Potential PaleoArchean Trace Fossils Mimic Biogenic Cenozoic Microbial Corrosion
Paleoarchean trace fossils in altered volcanic glass
Staudigel et al
Microbial corrosion textures in volcanic glass from Cenozoic seafloor basalts and the corresponding titanite replacement microtextures in metamorphosed Paleoarchean pillow lavas have been interpreted as evidence for a deep biosphere dating back in time through the earliest periods of preserved life on earth. This interpretation has been recently challenged for Paleoarchean titanite replacement textures based on textural and geochronological data from pillow lavas in the Hooggenoeg Complex of the Barberton Greenstone Belt in South Africa. We use this controversy to explore the strengths and weaknesses of arguments made in support or rejection of the biogenicity interpretation of bioalteration trace fossils in Cenozoic basalt glasses and their putative equivalents in Paleoarchean greenstones. Our analysis suggests that biogenicity cannot be taken for granted for all titanite-based textures in metamorphosed basalt glass, but a cautious and critical evaluation of evidence suggests that biogenicity remains the most likely interpretation for previously described titanite microtextures in Paleoarchean pillow lavas.
But are disputed!
Questioning the biogenicity of titanite mineral trace fossils in Archean pillow lavas
Grosch et al
Staudigel et al. (1) compare early Archean titanite microtextures to recent microtubules in Cenozoic volcanic seafloor glass to support a biogenic origin. However, given the 3.5 billion years of Earth history since eruption of the Archean lavas, many geological processes have affected these rocks, complicating the simple case for trace fossils. Using hollow and partially mineralized microtextures in modern seafloor basalt as an analog for argued microbial alteration of Archean glass is, in our opinion, a weak line of argument and an overextrapolated interpretation in support of biogenicity. The many assumptions required in their proposed bioalteration model are not supported by microbiological experiments or geological observations. For example, Staudigel et al. (1) require that hollow microbial tunnels are filled in by some process forming titanite, but when and how this occurs is not substantiated. The authors also contradict earlier work by abandoning organic carbon linings to the microtextures as evidence in support of biogenicity. Staudigel et al. provide no new data to support a biogenic origin, and we highlight that they have further complicated their lines of argument.
And then the original authors counter!
Reply to Grosch and McLoughlin: Glass bioalteration trace fossils can be preserved by titanite in Paleoarchean greenstones
Staudigel et al
Before debating the criticism that Grosch and McLoughlin (1) extend toward our paper (2), we point out that we agree on important issues, such as the difficulty of interpreting titanite textures in greenstones with complex metamorphic histories. We further agree with them that their images are too ambiguous to be certain of the presence of any biotextures.
We welcome Grosch and McLoughlin’s (1) clarification of their textural continuum of titanite textures in figure 1 of ref. 1, even though we are missing a genetic interpretation. We distinguish two types of titanite textures: (i) well-crystallized blade-like titanite crystals that have no resemblance to Cenozoic glass bioalteration and (ii) some “filamentous” textures that indeed closely resemble candidate biotextures. Lumping two visually distinct texture types into one group does not automatically give license to infer one process for their formation. Furthermore, we suggest here that none of the images conjure any simple metamorphic or biotic interpretations. In particular the candidate biotextures lack any obvious connections to glass surfaces or cracks in the glass, prohibiting a direct morphological comparison with Cenozoic biotextures.
Thursday, May 21, 2015
The J-20 combat aircraft, a new generation of combat aircraft, is currently engaged in intensive trial flights. According to photos circulating online, a newly designed J-20 coded 2013 carried out a series of low altitude maneuvers that demonstrated its relatively advanced performance.
Concerning the question of when the aircraft will be on active service, military expert Song Xinzhi said in a Beijing Television broadcast that J-20 is still using an prototype engine and it would be optimistic to expect it to come into service within one or two years.
From the photo we can clearly see features of the nose including the radome layout, the cockpit, and the canards.
An online report from Russia indicated that the maiden flight of the first prototype was made in January 2011, that China has already tested the sixth prototype of J-20, and that the J-20 at its initial stage is already an aircraft carrier killer.
According to the report, it takes five to six years for a new fighter to enter service. Therefore, it is very likely that this fighter will be equipped with a full set of avionics and arms in 2017.
Could the J-20 be operational within two years? Song Xinzhi points out that J-20 is still using a prototype engine which can only meet the demands of trial flights. A better engine is needed to unleash its full performance potential.
Machine learning can pinpoint rodent species that harbor diseases and geographic hotspots vulnerable to new parasites and pathogens. So reports a new study in the Proceedings of the National Academy of Sciences led by Barbara A. Han, a disease ecologist at the Cary Institute of Ecosystem Studies.
Most emerging infectious diseases are transmitted from animals to humans, with more than a billion people suffering annually. Safeguarding public health requires effective surveillance tools.
Han comments: "Historically, emerging infectious diseases have been dealt with reactively, with efforts focused on containing outbreaks after they've spread. We were interested in how machine learning could inform early warning surveillance by revealing the distribution of rodent species that are effective disease reservoirs."
Reappraisal of hydrocarbon biomarkers in Archean rocks
French et al
Hopanes and steranes found in Archean rocks have been presented as key evidence supporting the early rise of oxygenic photosynthesis and eukaryotes, but the syngeneity of these hydrocarbon biomarkers is controversial. To resolve this debate, we performed a multilaboratory study of new cores from the Pilbara Craton, Australia, that were drilled and sampled using unprecedented hydrocarbon-clean protocols. Hopanes and steranes in rock extracts and hydropyrolysates from these new cores were typically at or below our femtogram detection limit, but when they were detectable, they had total hopane (less than 37.9 pg per gram of rock) and total sterane (less than 32.9 pg per gram of rock) concentrations comparable to those measured in blanks and negative control samples. In contrast, hopanes and steranes measured in the exteriors of conventionally drilled and curated rocks of stratigraphic equivalence reach concentrations of 389.5 pg per gram of rock and 1,039 pg per gram of rock, respectively. Polycyclic aromatic hydrocarbons and diamondoids, which exceed blank concentrations, exhibit individual concentrations up to 80 ng per gram of rock in rock extracts and up to 1,000 ng per gram of rock in hydropyrolysates from the ultraclean cores. These results demonstrate that previously studied Archean samples host mixtures of biomarker contaminants and indigenous overmature hydrocarbons. Therefore, existing lipid biomarker evidence cannot be invoked to support the emergence of oxygenic photosynthesis and eukaryotes by ∼2.7 billion years ago. Although suitable Proterozoic rocks exist, no currently known Archean strata lie within the appropriate thermal maturity window for syngenetic hydrocarbon biomarker preservation, so future exploration for Archean biomarkers should screen for rocks with milder thermal histories.
Wednesday, May 20, 2015
A systematic revision of Proconsul with the description of a new genus of early Miocene hominoid
McNulty et al
For more than 80 years, Proconsul has held a pivotal position in interpretations of catarrhine evolution and hominoid diversification in East Africa. The majority of what we ‘know’ about Proconsul, however, derives from abundant younger fossils found at the Kisingiri localities on Rusinga and Mfangano Islands rather than from the smaller samples found at Koru—the locality of the type species, Proconsul africanus—and other Tinderet deposits. One outcome of this is seen in recent attempts to expand the genus “Ugandapithecus” (considered here a junior subjective synonym of Proconsul), wherein much of the Tinderet sample was referred to that genus based primarily on differentiating it from the Kisingiri specimens rather than from the type species, P. africanus. This and other recent taxonomic revisions to Proconsul prompted us to undertake a systematic review of dentognathic specimens attributed to this taxon. Results of our study underscore and extend the substantive distinction of Tinderet and Ugandan Proconsul (i.e., Proconsul sensu stricto) from the Kisingiri fossils, the latter recognized here as a new genus. Specimens of the new genus are readily distinguished from Proconsul sensu stricto by morphology preserved in the P. africanus holotype, but also in I1s, lower incisors, upper and lower canines, and especially mandibular characteristics. A number of these differences are more advanced among Kisingiri specimens in the direction of crown hominoids. Proconsul sensu stricto is characterized by a suite of unique features that strongly unite the included species as a clade. There have been decades of contentious debate over the phylogenetic placement of Proconsul (sensu lato), due in part to there being a mixture of primitive and more advanced morphology within the single genus. By recognizing two distinct clades that, in large part, segregate these character states, we believe that better phylogenetic resolution can be achieved.
New material of Pseudoloris parvulus (Microchoerinae, Omomyidae, Primates) from the Late Eocene of Sossís (northeastern Spain) and its implications for the evolution of Pseudoloris
Minwer-Barakat et al
The species Pseudoloris parvulus, identified in several Middle and Late Eocene European sites, was previously known in the Iberian Peninsula by a single mandible preserving P4–M3 from Sossís (Southern Pyrenean Basins, northeastern Spain), described in the 1960s. Further field work at this Late Eocene site has led to the recovery of a large number of mammal remains, including the additional material of P. parvulus described in this paper. Some specimens of P. parvulus from this locality have also been recently found in the collections of the Naturhistorisches Museum Basel, Switzerland. The whole sample consists of 11 mandible fragments including several teeth, three upper dental series and nearly 80 isolated teeth including all of the dental elements, and represents the most complete sample of the genus described from the Iberian Peninsula. This abundant material allows us to provide an emended diagnosis for the species and to observe several directional changes in the dental morphology of the lineage including the species Pseudoloris saalae, Pseudoloris isabenae, Pseudoloris pyrenaicus and P. parvulus. These directional changes include the progressive reduction of the paraconid in the lower molars and the increase in size of the hypocone, metaconule and paraconule in the upper molars. Moreover, despite the overall resemblance among all of the samples ascribed to P. parvulus, we also recognize some differences, particularly an increase in size and better development of the hypocone from the oldest populations of the species, such as Le Bretou, to the most recent ones, like Sossís and Perrière. Therefore, this study sheds new light on the evolution of this genus, which inhabited Europe from the Middle Eocene to the Early Oligocene.
Paleomagnetic study on mid-Paleoproterozoic rocks from the Rio de la Plata craton: Implications for Atlantica
Rapalini et al
The first successful paleomagnetic study on middle Paleoproterozoic rocks from the Rio de la Plata craton is reported. Samples collected from the Soca and Isla Mala granitic bodies, located in southern Uruguay, provided characteristic remanences that were used to compute the first paleomagnetic poles for the craton for ca. 2.05–2.02 Ga. The poles were complemented by a virtual geomagnetic pole from the slightly older Marincho and Mahoma complexes. The paleomagnetic results suggest fast apparent polar wander at high paleolatitudes for the Rio de la Plata craton. Comparison with coeval poles from the Guiana, Congo–São Francisco and West African cratons indicates that a configuration of Atlantica that resembles their Western Gondwana fit is not supported by paleomagnetic data. The geologic similarities in these four cratons are supportive of a major crustal forming event between 2.2–2.0 Ga. A modified configuration for Atlantica is proposed that is consistent with our new (and older) paleomagnetic data. Atlantica was assembled at 2.1–2.05 Ga at polar latitudes and drifted towards the equator soon afterwards.
Tuesday, May 19, 2015
Quantitative inferences on the locomotor behaviour of extinct species applied to Simocyon batalleri (Ailuridae, Late Miocene, Spain)
Fabre et al
Inferences of function and ecology in extinct taxa have long been a subject of interest because it is fundamental to understand the evolutionary history of species. In this study, we use a quantitative approach to investigate the locomotor behaviour of Simocyon batalleri, a key taxon related to the ailurid family. To do so, we use 3D surface geometric morphometric approaches on the three long bones of the forelimb of an extant reference sample. Next, we test the locomotor strategy of S. batalleri using a leave-one-out cross-validated linear discriminant analysis. Our results show that S. batalleri is included in the morphospace of the living species of musteloids. However, each bone of the forelimb appears to show a different functional signal suggesting that inferring the lifestyle or locomotor behaviour of fossils can be difficult and dependent on the bone investigated. This highlights the importance of studying, where possible, a maximum of skeletal elements to be able to make robust inferences on the lifestyle of extinct species. Finally, our results suggest that S. batalleri may be more arboreal than previously suggested.