pinecone/core-2020-05-10-deduplication huggingface dataset:
The plumbing of Old Faithful Geyser revealed by hydrothermal tremor

International audienceOld Faithful Geyser in Yellowstone National Park (USA) has attracted numerous scientific investigations for over two centuries in order to better understand its geological structure, the physics of its eruptions, and the controls of its intermittency. Using data acquired with a seismic array in 1992, we track the sources of hydrothermal tremor produced by boiling and cavitation inside the geyser. The location of seismic sources identifies a previously unknown lateral cavity at 15 m below the surface, on the SW side of the vent, and connected to the conduit. This reservoir is activated at the beginning of each geyser eruption cycle and plays a major role in the oscillatory behavior of the water level in the conduit before each eruption
Rare earth element sorption onto hydrous manganese oxide: A modeling study

International audienceManganese oxides are important scavengers of rare earth elements (REE) in hydrosystems. However, it has been difficult to include Mn oxides in speciation models due to the lack of a comprehensive set of sorption reactions consistent with a given surface complexation model (SCM), as well as discrepancies between published sorption data and predictions using the available models. Surface complexation reactions for hydrous Mn oxide were described using a two surface site model and the diffuse double layer SCM. The specific surface area, surface side density, and pHzpc were fixed to 746 m2/g, 2.1 mmol/g, and 2.2, respectively. Two site types (triple bond; length of mdashXOH and triple bond; length of mdashYOH) were also used with pKa2 values of 2.35 (triple bond; length of mdashXOH) and 6.06 (triple bond; length of mdashYOH). The fraction of the high affinity sites was fixed at 0.36. Published REE sorption data were subsequently used to determine the equilibrium surface complexation constants, while considering the influence of pH, ionic strength, and metal loading. Log K increases from light REE to heavy REE and, more specifically, displays a convex tetrad effect. At low metal loading, the triple bond; length of mdashYOH site type strongly expresses its affinity toward REE, whereas at higher metal loading, the same is true for the triple bond; length of mdashXOH site type. This study thus provides evidence for heterogeneity in the distribution of the Mn oxide binding sites among REE
Comparison of statistical algorithms for detecting homogeneous river reaches along a longitudinal continuum

International audienceSeven methods designed to delineate homogeneous river segments, belonging to four families, namely -- tests of homogeneity, contrast enhancing, spatially constrained classification, and hidden Markov models -- are compared, firstly on their principles, then on a case study, and on theoretical templates. These templates contain patterns found in the case study but not considered in the standard assumptions of statistical methods, such as gradients and curvilinear structures. The influence of data resolution, noise and weak satisfaction of the assumptions underlying the methods is investigated. The control of the number of reaches obtained in order to achieve meaningful comparisons is discussed. No method is found that outperforms all the others on all trials. However, the methods with sequential algorithms (keeping at order n + 1 all breakpoints found at order n) fail more often than those running complete optimisation at any order. The Hubert-Kehagias method and Hidden Markov Models are the most successful at identifying subpatterns encapsulated within the templates. Ergodic Hidden Markov Models are, moreover, liable to exhibit transition areas
Potentially toxic element phytoavailability assessment in Technosols from former smelting and mining areas

International audienceThis study reports the chemical bioavailability of several potentially toxic elements (Zn, Pb, Cd, As, and Sb) in contaminated Technosols from two former smelting and mining areas. Though these elements have long been recognized as potentially harmful elements, understanding of their toxicity and environmental behavior in Technosols developed on former mining and smelting sites are more limited, particularly for As and Sb. Surface soils were sampled from metallophyte grassland contaminated with Zn, Pb, and Cd located at Mortagne-du-Nord (North France) and from a former mining settling basin contaminated with As, Pb, and Sb located at la Petite Faye (Limoges, France). Various selective single extraction procedures (CaCl2, NaNO3, NH4NO3, DTPA, and EDTA) were used together with germination tests with dwarf beans whose shoots were analyzed for their potentially toxic element concentrations after 21 days of growth. The extraction capacity of the potentially toxic elements followed the order EDTA > DTPA > NH4NO3 > CaCl2 > NaNO3 for both studied areas. Pearson’s correlation coefficient analysis between the concentrations of potentially toxic elements accumulated in bean primary leaves or their mineral mass with their extractable concentrations showed a positive significant correlation with dilute CaCl2 and nitrate solutions extraction procedures. In contrast, for all studied elements, except Pb, the complexing and chelating extractants (EDTA and DTPA) exhibited poor correlation with the dwarf bean leaves concentrations. Moreover, results showed that the 0.01 M CaCl2 extraction procedure was the most suitable and provided the most useful indications of metal phytoavailability for studied elements
Tailoring bulk and surface grafting of poly(acrylic acid) in electron-irradiated PVDF

International audienceEndowing conventional hydrophobic poly(vinylidene fluoride) (PVDF) films with hydrophilic properties was conducted using electron beam irradiation. Grafting of acrylic acid (AA) in/onto pre-irradiated PVDF films was investigated. Reaction parameters, monomer concentration and inhibitor concentration were examined. Radiation grafted films (PVDF-g-PAA) were synthesized with various grafting yields ranging from 12 to 130 wt % in presence of Mohr's salt (25 wt %). Below 80 wt % of monomer concentration, the degree of swelling was found to increase with the grafting yield. The PAA was arranged randomly in all PVDF matrix (grafting through). Above 80 wt % of monomer concentration, the PAA was grafted only onto the surface of PVDF films leading to a highly dense layer of PAA. Grafting through or surface grafting processes were achieved by varying the water fraction in the initial monomer solution. Water molecule acts not only as a carrier for the monomer but also as a plasticizer expanding the film in the three dimensions. Evidences of grafting through and surface grafting were produced using FTIR in ATR mode, SEM coupled to X-ray detection and XPS. An accurate quantification of AA units was possible up to the micromole via a Cu 2C –EDTA complex analyzed by UV–vis spectroscopy.
PIXE analyses over a long period: The case of Neolithic variscite jewels from Western Europe (5th-3th millennium BC)
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The case of Neolithic variscite jewels from Western Europe (5th-3th millennium BC)

International audiencePIXE analysis of archeological variscite beads and pendants from the Neolithic period that were excavated in Spain, Portugal and France and of variscite geological references samples from European occurrences were carried out from 1999 to 2013 in order to trace back the circulation of this precious gemstone over three millennia. Transformations of the AGLAE external beam system and progress in spectrum processing have induced some apparent compositional variation, affecting in particular the phosphorus/aluminum ratio. This long term evolution has been taken into account with the help of geostandards to build a large and coherent geochemical database of minor and trace elements in variscite. This database allowed us to determine the provenance of the raw material and thus of the circulation of the jewels
Precambrian tectonic evolution of Central Tianshan, NW China: constraints from U-Pb dating and in-situ Hf isotopic analysis of detrital zircons

International audienceThe Tarim Block is an important geologic unit in the reconstruction of the tectonic evolution of the Central Asian Orogenic Belt and the Precambrian Columbia and Rodinia supercontinents. In order to examine the evolution and crustal generation of the Tarim Block, we performed detrital zircon U-Pb dating and in-situ Hf isotopic analysis of Devonian sandstones of the Baluntai area in Central Tianshan, which is part of the Tarim Block. Most analyzed zircon grains show oscillatory zoning and have Th/U ratios >0.4, suggesting that they were mainly derived from igneous rocks. A total of about 400 detrital zircon analyses yielded five age populations, namely, early Paleoproterozoic (peak at 2470 Ma), middle Paleoproterozoic (peak at 1858 Ma), early Mesoproterozoic (peak at 1541 Ma), early Neoproterozoic (peak at 952 Ma), and late Neoproterozoic (820 to 750 Ma). These peak ages are remarkably consistent with the polyphase tectonothermal events that occurred in the Tarim Block. The peak at 2470 Ma indicates the presence of late Neoarchean to early Paleoproterozoic magmatism in the Tarim Block. The two peaks at 1858 Ma and 952 Ma coincide with the two periods of assembly of the Columbia and Rodinia supercontinents. This further suggests that the Tarim Block was part of these two supercontinents. In fact, the age peak of 1541 Ma correlates with the breakup of Columbia, and the age range of 820 to 750 Ma is interpreted to represent the time of the breakup of Rodinia. The zircon Hf model ages suggest three major stages of crustal evolution at 1.0-1.4 Ga, 1.8-3.3 Ga, and 3.4-3.8 Ga. The zircons exhibit a huge range of var epsilonHf(t) values from −33 to +51, suggesting that they were derived from highly diverse protoliths. However, since most detrital zircons show negative var epsilonHf(t) values, the protoliths of the Baluntai sandstones of Central Tianshan probably comprise rocks of Archean to Proterozoic crust. Owing to the similar Precambrian basement, lithology and age spectra between Central Tianshan and Tarim, it is argued that Central Tianshan belonged to the Tarim Block in the Precambrian time. Furthermore, euhedral zircons with high Th/U ratios (>0.4) yielded a prominent peak of 447 Ma. This can be correlated with an early Paleozoic arc development in Central Tianshan
Origin of growth defects in pearl

International audiencePearls are produced from a natural biomineralisation process. The structural unit is a biocrystal whose formation is controlled by organic molecules. In the present paper we studied a major growth defect to highlight the role of the organics in the growth mechanism. Some freshwater pearls exhibit a lack of lustre, also known as 'milky pearl' defect. This defect is related to the formation of vaterite instead of aragonite during the biomineralisation growth process. We used Rock Eval pyrolysis, a new technique in this field, to quantify a noticeable increase of the organic matrix in milky pearls. At least 20% more organics were found when vaterite forms than aragonite. To further study its role during the growth process, the organic matrix was extracted using three different protocols and characterised by infrared spectroscopy (FTIR) and liquid chromatography (HPLC). The fraction of the organic matrix which is soluble in water (WSM fraction) was significantly different when analysed by FTIR and by HPLC. This fraction is very likely occluded within the mineral (intracrystalline matrix). To examine its role, WSM extracted from milky pearls was used as additive in controlled calcium carbonate growth experiments. In this case, vaterite crystals were obtained for the greater part. When WSM extracted from healthy pearls was used, aragonite and calcite crystals were grown. The polymorph (vaterite vs aragonite) appeared to be clearly connected to the WSM organic fraction. Several hypotheses may explain this result: e.g., a minor disorder of the organic composition of the extrapallial fluid, an excess of Mn or Mg or a blocking of the growth at a transient stage. Final
The Scherk-Schwarz mechanism as a flux compactification with internal torsion

The aim of this paper is to make progress in the understanding of the Scherk-Schwarz dimensional reduction in terms of a compactification in the presence of background fluxes and torsion. From the eleven dimensional supergravity point of view, we find that a general E6(6) S-S phase may be obtained by turning on an appropriate background torsion, together with suitable fluxes, some of which can be directly identified with certain components of the four-form field-strength. Furthermore, we introduce a novel (four dimensional) approach to the study of dualities between flux/torsion compactifications of Type II/M-theory. This approach defines the action that duality should have on the background quantities, in order for the E7(7) invariance of the field equations and Bianchi identities to be restored also in the presence of fluxes/torsion. This analysis further implies the interpretation of the torsion flux as the T-dual of the NS three-form flux
Becoming Global (Un)Civil Society: Counter-Hegemonic Struggle and the Indymedia Network

In this article we ask how ‘civil society’ actors and organizations can become constructed and treated as ‘uncivil society’. We contest the notion that ‘uncivil’ necessarily equates with the dark qualities of violence and organized criminality. Instead, we take a Gramscian perspective in suggesting that what becomes ‘uncivil’ is any practice and organization that substantially contests the structuring enclosures of hegemonic order, of which civil society is a necessary part. To trace this, we consider ways in which a global grass-roots media network called Indymedia has established and maintained itself as a counter-hegemonic media-producing organization. In this case, a conscious positioning and self-identification as counter-hegemonic has been accompanied by the framing and sometimes violent policing of nodes and practices of this network as ‘uncivil’ by cooperating state authorities. This is in the absence of association of this network with organized violence or crime. We intend our reflections to contribute to a deepening theorization of the terms ‘civil’ and ‘uncivil’ as they are becoming used in social movement and globalization studies
CPVMatch - Concentrating photovoltaic modules using advanced technologies and cells for highest efficiencies

This paper presents the project Concentrating Photovoltaic modules using advanced technologies and cells for highest efficiencies (CPVMatch), which is funded from the European Union’s Horizon 2020 research and innovation programme.  V multi-junction solar cells and CPV modules. Concerning cells, novel wafer bonded four-junction solar cells made of GaInP/GaAs//GaInAs/Ge are optimized with the target of reaching 48% efficiency under concentration at the end of the project. Moreover, multi-junction solar cell technologies with advanced materials - like ternary IV element mixtures (i.e. SiGeSn) and nanostructured anti-reflective coatings - are investigated. Concerning CPV modules the project focuses on both Fresnel-based and mirror-based technologies with a target efficiency of 40% under high concentrations beyond 800x. Achromatic Fresnel lenses for improved light management without secondary optics are investigated. In addition, smart, mirror-based HCPV modules are developed, which include a new mirror-based design, the integration of high efficiency, low cost DC/DC converters and an intelligent tracking sensor (PSD sensor) at module level. A profound life-cycle and environmental assessment and the development of adapted characterization methods of new multi-junction cells and HCPV modules complete the work plan of CPVMatch
Causality and Contagion in EMU Sovereign Debt Markets

This paper contributes to the literature by applying the Granger-causality approach and endogenous breakpoint test to offer an operational definition of contagion to examine European Economic and Monetary Union (EMU) countries public debt behavior. A database of yields on 10-year government bonds issued by 11 EMU countries covering fourteen years of monetary union is used. The main results suggest that the 41 new causality patterns, which appeared for the first time in the crisis period, and the intensification of causality recorded in 70% of the cases provide clear evidence of contagion in the aftermath of the current euro debt crisis
Measurement of the Horizon Elevation for satellite tracking antennas Located in Urban and Metropolitan Areas Combining Geographic and Electromagnetic Sensors

In urban and metropolitan areas presence of nearby obstacles and signal interference sources surrounding tracking antenna locations reduces satellite communication times. In low orbit missions these obstructions are even more relevant due to a few minutes per satellite pass. In this scenario a best estimation of the antenna elevation mask in the mission frequency band is proposed to test the antenna design for a given site by applying mission simulation software before the installation stage. If needed, to improve efficiency in satellite tracking operations, mitigation techniques will be proposed either in the redesign or relocation of the antenna.\ud
This paper describes a methodology for deriving the horizon elevation diagram, which includes a measurement setup when different data capturing sensors are used: geographic and electromagnetic. Application results which have contributed in the selection of the antenna location can be seen in the case study of the new CubeSat-LEO tracking antenna at Cal Poly University
Fabrication of aluminum matrix composites reinforced with nano- to micrometer-sized SiC particles

In this study, the hot extrusion process was applied to stir cast aluminum matrix–SiC composites in order to improve their microstructure and reduce cast part defects. SiC particles were ball milled with Cr, Cu, and Ti as three forms of carrier agents to improve SiC incorporation. Large brittle ceramic particles (average particle size: 80 μm) were fragmented during ball-milling to form nanoparticles in order to reduce the cost of composite manufacturing. The experimental results indicate that full conversion of coarse micron sized to nanoparticles, even after 36 h of ball milling, was not possible. Multi modal SiC particle size distributions which included SiC nanoparticles were produced after the milling process, leading to the incorporation of a size range of SiC particle sizes from about 50 nm to larger than 10 μm, into the molten A356 aluminum alloy. The particle size of the milled powders and the amount of released heat from the reaction between the carrier agent and molten aluminum are inferred as two crucial factors that affect the resultant part tensile properties and microhardness
Building Accessible Flash Applications: an XML-Based Toolkit

The use of Flash as a web-based multimedia development tool has spread lately. Although a big effort has gone into improving its accessibility, there are still accessibility gaps requiring programming or purchase from another supplier. This makes building an accessible Flash application an ad hoc, complex and time-consuming task. With the aim of lightening the accessibility-related workload, we have implemented a toolkit that helps to create accessible multimedia Flash resources. This toolkit specifies the accessibility features as XML configuration files. It includes a library that works like a wrapper abstracting the logic layer of the different events and iterations from the physical layer. This way, new functionalities can easily be added. Additionally, it has been successfully used to build teaching and teaching support systems
Hydrothermal monitoring using embedded sensors of the actual roof system of the prado museum

El Prado Museum in Madrid has been recently submitted to a refurbishment of its roof which from been made with the traditional tiles has been changed to the use of modern waterproofing layers covered with a metallic lead finishing. Due to an unexpected damp patch that produced leaking in the hall in which Las Meninas by Velázquez was exhibited, the authors were commissioned by the Ministry of Education and Culture to study the suitability of the roof and its waterproofing properties. The study led to suggestions of modifications in the design of the roof layers, which are out of the scope of present paper. In present paper are given the behaviour of the sensors embedded in two specific areas of the roof. The sensors installed were of: temperature, relative humidity, measurement of local strain and detection of liquid water. The liquid water sensors reveal that some water is withheld in the layer just below the thermal insulation material, although it is standing. The results of over four years of readings show that the temperature attenuates over distance away from the outermost layer, where the readings are very high in summer, due to it consists of lead. During the colder seasons, in turn, the temperature in the inner layers of the roof is higher than in the outer layers. The strain recorded follows the logical evolution of temperature with no abnormal behaviour being detected. Some of relative humidity sensors had measuring problems due to water condensing on them. In summary however, if the behaviour in this area is extrapolated to the rest of the roof, it can be considered to perform correctly as intended. No more leaking events have been detected from the design modifications were incorporated to the existing roof
An improved bit parallel exact maximum clique algorithm

This paper describes new improvements for BB-MaxClique (San Segundo et al. in Comput Oper Resour 38(2):571–581, 2011 ), a leading maximum clique algorithm which uses bit strings to efficiently compute basic operations during search by bit masking. Improvements include a recently described recoloring strategy in Tomita et al. (Proceedings of the 4th International Workshop on Algorithms and Computation. Lecture Notes in Computer Science, vol 5942. Springer, Berlin, pp 191–203, 2010 ), which is now integrated in the bit string framework, as well as different optimization strategies for fast bit scanning. Reported results over DIMACS and random graphs show that the new variants improve over previous BB-MaxClique for a vast majority of cases. It is also established that recoloring is mainly useful for graphs with high densities
A review of HSR experiences around the world

High Speed Railways (HSR) is currently regarded as one of the most significant technological breakthroughs in passenger transportation developed in the second half of the 20th century. At the beginning of 2008 there were about 10,000 kilometres of new high speed lines in operation around the world and, in total (including upgraded conventional tracks), more than 20,000 kilometres of the worldwide rail network was devoted to provide high speed services to passengers willing to pay for a lower travel time and a quality improvement in rail transport. 

However, building, maintaining and operating HSR lines is expensive, involves a significant amount of sunk costs and may substantially compromise both the transport policy of a country and the development of its transport sector for decades. For these reasons it deserves a closer look, well beyond the technological hype and the demand figures. The main objective of this paper is to discuss some characteristics of the HSR services from an economic viewpoint, while simultaneously developing an empirical framework that help us to understand in more detail the cost and demand sides of this transport alternative. This understanding is especially useful for future projects, since it will lead to a better analysis of the expected construction and operating costs, and of the number of passengers to be carried out under different economic and geographic conditions.