bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chemistry of protopyroxene, orthopyroxene and pigeonite, crystallised from liquids close to chondrule compositions
Authors: Biggar Gordon 
Published: March 2019

Des gels synthétiques incluant la gamme de composition habituelle des chondrules ont été équilibrés en présence du tampon fer-wüstite de 1225 à 1375°C. Les phases au liquidus sont variables ; protopyroxène, orthopyroxène, pigeonite et olivine. Pour certaines compositions un pyroxène cristallise mais il est remplacé par un autre aux plus basses températures.
La minéralogie et le chimisme des pyroxènes (en particulier leur contenu en CaO et Al2O3) reflètent, dans leurs variations le rapport fixé (CaO + Na2O)/Al2O3 des compositions globales. Tous ces pyroxènes contiennent progressivement moins de CaO quand les teneurs en fer augmentent.
Le protopyroxène contient moins de 0,6 % de CaO et persiste jusqu'à la composition En86 avant son remplacement par l'orthopyroxène renfermant 2,0 à 0,6 % de CaO qui survit jusqu'à une limite mal connue entre En83 et En71 où il est remplacé, à son tour, par de la pigeonite. La pigeonite magnésienne contient très peu de Al2O3 (<0,1 %) et est remplacée par de l'orthopyroxène (jusqu'à 1,3 % Al2O3) voire éventuellement par du protopyroxène pour les liquides pauvres en CaO, riches en Al2O3. Dans les liquides plus riches en fer, l'orthopyroxène n'est plus stable et la pigeonite doit incorporer Al2O3 en excès (jusqu'à 0,6 %). Les coefficients de distribution FeO/MgO pyroxène-liquide, varient avec la température et vont de 0,29 à 0,45. Les liquides riches en CaO deviennent encore plus riches en fer quand le pyroxène cristallise mais les liquides riches en MgO et Al2O3 montrent une évolution contraire. Des gains et pertes en Na2O ont été observés dans les expériences et son caractère volatil mis en évidence dans les chondrules. Des exemples de pyroxène dans les chondrules sont comparés avec ces pyroxènes synthétiques.
A thermoluminescence study of the rôle of a middle proterozoic unconformity in controlling uranium mineralization, as shown at Eyre Peninsula, South Australia
Authors: Ypma Petrus Johannes Maria , Hochman Mark B. M. 
Published: March 2019

Thermoluminescence research over the last three years has reached the point that radiation effects can be recognized in natural minerals, among which quartz ideally suited because of its small variation in chemical composition. The major radiation-related effects of quartz are sensitization (increasing the TL efficiency of the test dose) and a high temperature shift of TL glow peaks with increasing radiation doses. Those two criteria have been used to assess the TL glow curves of quartz obtained from samples near a Carpentarian unconformity in Eyre Peninsula, South Australia. The TL results indicate that radiation affected a zone of narrow (50 m) width of Lower Proterozoic rocks occurring immediately under the unconformity sediments of Carpentarian age. Vertical drill holes cutting through the unconformity surface yielded sample material which demonstrated diminishing radiation effects away from the unconformity.
Maximal radiation effects, which are compatible with an uranium content of 100 ppm residing in the zone over a period 1 400 Ma, are confined to the Carpentarian unconformity and its immediate vicinity. The results indicate that the mineralization took place under a Carpentarian cover, and was not sourced in the Lower Proterozoic metamorphics. From the homogeneous distribution of radiation effects it seems likely that the mineralization spread under the cover and only penetrated greater depths in shear zones. In areas where erosion has removed the Carpentarian cover and part of the metamorphic rocks under it, those shear zones are the only rocks affected by radiation.
Uranium behaviour in a gossan-type weathering system : example of the Bertholène deposit (Aveyron, France)
Authors: Schmitt Jean-Michel , Thiry Médard 
Published: March 2019

Dans le gisement de Bertholène, les corps uranifères subverticaux montrent une zonation hydrothermale primaire constituée de bas en haut par des brèches à carbonates, des brèches à sulfures, des faciès minéralisés à pechblende, et des faciès hématisés. L'évolution supergène quaternaire de ces minéralisations leur a surimposé une zonation de type "chapeau de fer". Le comportement de l'uranium résulte à la fois de sa position dans le profil d'altération et de la composition de la paragenèse primaire :
— Dans la zone ferruginisée supérieure, où le milieu reste proche de la neutralité, les minéralisations s'altèrent en vanadates et en phosphates.
— Dans la zone blanchie, l'altération des sulfures conduit à des milieux très acides et riches en silice dissoute et il y a coffinitisation.
— Dans la zone d' enracinement, située essentiellement sous le niveau phréatique, on retrouve des conditions proches de la neutralité et les minéralisations primaires sont préservées.
Les résultats d'une étude antérieure sur les déséquilibres de radioactivité confirment et complètent ce schéma général du comportement de l'uranium et de sa mobilité durant l'altération.
Physical and chemical controls (fO2,T,pH) of the opposite behaviour of U and Sn-W as examplified by hydrothermal deposits in France and Great-Britain, and solubility data
Authors: Dubessy Jean , Ramboz Claire , Nguyen-Trung Chinh , Cathelineau Michel , Charoy Bernard , Cuney Michel , Leroy Jacques , Poty Bernard , Weisbrod Alain 
Published: March 2019

The aim of this paper is to determine the physical and chemical parameters which control the opposite behaviour of uranium and tin-tungsten between 300° and 500 °C. In uranium deposits, fO2 and fS2 of mineralizing fluids are higher than values fixed by the pyrite-hematite-magnetite triple point, as shown by uraninite-hematite and/or pyrite mineral association. The stability of quartz-K feldspar-muscovite paragenesis in the wall-rocks of hydrothermal U deposits indicates weakly acid pH. By contrast, in the Sn-W occurrences from the French Southern Massif Central, the fO2 of mineralizing fluids is between Ni-NiO and Q-F-M buffers as shown by CO2-CH4-H2O-NaCl bearing fluid inclusions. The pH of these fluids is weakly acid to weakly basic as shown by the stability of muscovite in presence or absence of quartz and/or feldspar. Sn-W mineralizing fluids from Cornwall are by contrast purely aqueous and acid, as indicated by the mineral assemblage muscovite-quartz which is typical of greisens.
Experimental data on UO2, SnO2, FeWO4, CaWO4 solubility and metal species in fluids show that fO2 > H-M are required for uranium transport whereas fO2 ≤ Ni-NiO favours Sn transport. The fluid oxidation state has no direct influence on the transport and deposition of tungsten. The fO2 control on the hydrothermal transport properties of these three metals is related on the one hand to the fluid and rock composition, and on the other hand to the minimal 320 °C temperature required for homogeneous equilibria in the C-O-H system to control the oxidation state at low values.
At high temperatures, Sn, Fe and Ca chloride complexes are more stable than carbonate and phosphate uranium complexes ; this is attributable to their structure and to the dielectric content of the fluid. The presence of dissolved gases at high concentration, which are produced by devolatilization reactions at high temperatures, is emphasized since they lower the dielectric constant of the fluid which enhances the stability of chloride complexes.
All these results show that temperature and fO2 account for the opposite behaviour of uranium and tin-tungsten in hydrothermal systems between 300° to 500 °C.
Répartition de l'uranium dans les roches volcaniques
Authors: Flehoc Christine , Toulhoat Nelly , Villemant Benoît 
Published: March 2019

La méthode des traces de fission de l'uranium est appliquée à l'étude de sa répartition dans les roches volcaniques. Les exemples étudiés proviennent des séries de la Chaîne des Puys (Massif Central, France), du Vico, du Vulsini et du Cimino (Latium, Italie centrale).
— L'enrichissement systématique de l'uranium dans les mésostases et les verres par rapport aux phases cristallines, quels que soient le degré de différenciation et la teneur en uranium des laves, traduit la stabilité préférentielle de l'uranium dans les liquides magmatiques.
— Le degré de cristallinité des mésostases et leurs textures déterminent le caractère homogène ou non de la répartition de l'uranium dans celles-ci.
— Des phénomènes de mobilisation et de redistribution de l'uranium à des stades tardifs, voire postmagmatiques, sont mis en évidence par des associations uranium-minéraux qui diffèrent de celles du stade magmatique et par des modifications de répartition dans les mésostases.
La distribution de l'uranium entre mésostase et phases minérales que l'on observe conduit à proposer l'existence de formes complexées de type urano-silicatées ou urano-phosphatées stabilisant cet élément dans les liquides magmatiques et préfigurant son enrichissement sélectif dans les minéraux accessoires les plus fréquents des roches volcaniques.
Le karst du Yucatàn : rôle du flux géothermique, des failles, de l'eau de mer et des évaporites dans sa genèse
Authors: Thomas Christian 
Published: March 2019

Dans les karsts à lentille d'eau douce, le plongeur souterrain qui franchit l'halocline découvre que l'eau salée sous-jacente est plus chaude que l'eau douce surnageante. Il constate aussi qu'il existe des cénotes «chauds » et des cénotes «froids ». Comment expliquer ces disparités thermiques ? Pourquoi l'aquifère salin est-il plus chaud que l'aquifère d'eau douce ? Ces sauts de température indiquent en fait un mode de transfert de la chaleur d'origine géothermique par convections et l'existence de deux systèmes de panaches thermiques (eau douce et eau salée). La plateforme du Yucatan a fait l'objet d'explorations spéléologiques intenses et de nombreuses mesures physico-chimiques, ce qui nous a permis de quantifier les ordres de grandeurs de ces phénomènes. La modélisation numérique permet de définir l'existence des conditions d'établissement de tels régimes d'écoulement et souligne l'importance de la conductivité hydraulique et du rôle de la fracturation. L'apport de la géochimie des eaux douces permet d'évaluer la profondeur à laquelle se forment les panaches thermiques.
L'analyse des échanges thermiques avec les eaux profondes de la mer Caraïbe ainsi que le rôle antagoniste de la lagune de Yalahau sont avancés pour expliquer la zone «froide » située au nord-est de la péninsule. Les mécanismes de karstification, amplifiés par des effets rétroactifs qui résultent de ces mouvements d'eau sont développés. La genèse des blue holes et l'existence de courtes galeries horizontales au niveau de l'halocline peuvent s'expliquer de cette façon. L'ablation karstique des évaporites du Crétacé notamment dans la zone du lac de Chichencanab est évaluée, ce qui apporte une interprétation inédite de l'existence de grandes structures d'effondrement visibles en photographie satellite dans cette zone. Ces phénomènes de creusement karstique, de nature hypogène, ne sont pas directement influencés par la pluviométrie, le «moteur » d'écoulement étant uniquement thermique.
Reconstitution de l'entrée préhistorique de la grotte Chauvet-Pont d'Arc (Ardèche, France) : les apports de l'analyse géomorphologique et de la modélisation 3D
Authors: Delannoy Jean-Jacques , Sadier Benjamin , Jaillet Stéphane , Ployon Estelle , Geneste Jean-Michel 
Published: March 2019

Reconstruction of the prehistoric entrance of the Chauvet Cave (Ardèche, France) : the contribution of geomorphologic analysis and 3d modelling.
The exceptional state of conservation of the Chauvet Cave is mostly due to its sealing because of the collapse of the limestone ledge that used to overhang the prehistoric entrance. This article gives the very first synthesis of the works that have been carried out since 2005 on the entrance of the cave. Special attention is paid to the reconstruction and the chronology of the events that lead to the sealing of the cave. This reconstruction relies on a method coupling the geomorphologic approach and the 3D modelling with digital clones acquired by lasergrammetry. This original method allowed us to find the former extension of the Chauvet Cave that was cut off by the receding of the slope, to detail the features as well as the size of the prehistoric porch, and to assess the processes that occurred during the sealing of the cave. A relative chronology of the events is proposed in this article, in the present absence of dates able to constrain the morphogenetic model. After presenting the contribution of geomorphologic mapping to the understanding of the events that shaped the present relief, we elaborate on the contribution of 3D modelling to spatialise the geomorphologic data and better take into account the spatial and geometrical constraints. With this approach, we reveal the role of the ceiling pendants in the spreading of collapsed rocks within the cave and thus better grasp the structure of the internal scree ; likewise the identification of a gallery that was cut off allowed us to better understand the distribution of the collapsed rocks at the base of the scar and the small spatial extension of the internal scree. Finally, the analysis with high spatial resolution of the scar allowed us to estimate the volume of collapsed rocks and to measure their impact on the sealing of the cave. The age of the sealing is estimated with data today available from the dating of speleothems that seal up the scree and the underground fauna. The proposed bracket remains wide on the basis of these data : the cave was blocked off between 23 000 and 11 500 BP. In order to reduce this age bracket, we propose leads that could be followed to date the scar of the rockfall.
Adjective ordering in Tagalog: A cross-linguistic comparison of subjectivity-based preferences
Authors: Samonte Suttera , Scontras Gregory 
Published: March 2019

Previous studies have shown that speakers have robust adjective ordering preferences. For example, in English, big red apple is strongly preferred to red big apple. Recently, Scontras et al. (2017) showed that an adjective’s distance from the noun it modifies is best predicted by the adjective’s subjectivity, with less subjective adjectives preferred closer to the modified noun. However, this finding was limited to English. The current study investigates the status of subjectivity-based adjective ordering preference in Tagalog, a language that forms its modification structures with the conjunction-like LINKER particle. Using Tagalog translations of the original English materials, we show that subjectivity predicts ordering preferences in Tagalog, as it does in English.
Changing-look Quasar Candidates: First Results from Follow-up Spectroscopy of Highly Optically Variable Quasars
Authors: MacLeod Chelsea L. , Green Paul J. , Anderson Scott F. , Bruce Alastair , Eracleous Michael , Graham Matthew , Homan David , Lawrence Andy , LeBleu Amy , Ross Nicholas P. , Ruan John J. , Runnoe Jessie , Stern Daniel , Burgett William , Chambers Kenneth C. , Kaiser Nick , Magnier Eugene , Metcalfe Nigel 
Published: March 2019

Abstract
Active galactic nuclei (AGNs) that show strong rest-frame optical/UV variability in their blue continuum and broad line emission are classified as changing-look AGN, or at higher luminosities, changing-look quasars (CLQs). These surprisingly large and sometimes rapid transitions challenge accepted models of quasar physics and duty cycles, offer several new avenues for study of quasar host galaxies, and open a wider interpretation of the cause of differences between broad and narrow-line AGN. To better characterize extreme quasar variability, we present follow-up spectroscopy as part of a comprehensive search for CLQs across the full Sloan Digital Sky Survey (SDSS) footprint using spectroscopically confirmed quasars from the SDSS DR7 catalog. Our primary selection requires large-amplitude (

mag,

mag) variability over any of the available time baselines probed by the SDSS and Pan-STARRS 1 surveys. We employ photometry from the Catalina Sky Survey to verify variability behavior in CLQ candidates where available, and confirm CLQs using optical spectroscopy from the William Herschel, MMT, Magellan, and Palomar telescopes. For our adopted signal-to-noise ratio threshold on variability of broad Hβ emission, we find 17 new CLQs, yielding a confirmation rate of ≳20%. These candidates are at lower Eddington ratio relative to the overall quasar population, which supports a disk-wind model for the broad line region. Based on our sample, the CLQ fraction increases from 10% to roughly half as the continuum flux ratio between repeat spectra at 3420 Å increases from 1.5 to 6. We release a catalog of more than 200 highly variable candidates to facilitate future CLQ searches.
Magnetic Properties and Flow Angle of the Inverse Evershed Flow at Its Downflow Points
Authors: Beck C. , Choudhary D. P. 
Published: March 2019

Abstract
We determined the direction and strength of the photospheric and lower chromospheric magnetic field in the umbra and penumbra of a sunspot from inversions of spectropolarimetric observations of photospheric lines at 617 nm and 1565 nm and the chromospheric Ca ii IR line at 854 nm, respectively. We compare the magnetic field vector with the direction of 75 flow channels that harbor the chromospheric inverse Evershed effect (IEF) near their downflow points (DFPs) in the sunspot’s penumbra. The azimuth and inclination of the IEF channels to the line of sight (LOS) were derived from spatial maps of the LOS velocity and line–core intensity of the Ca ii IR line and a thermal inversion of the Ca ii IR spectra to obtain temperature cubes. We find that the flow direction of the IEF near the DFPs is aligned with the photospheric magnetic field to within about ±15°. The IEF flow fibrils make an angle of 30°–90° to the local vertical with an average value of about 65°. The average field strength at the DFPs is about 1.3 kG. Our findings suggest that the IEF in the lower chromosphere is a field-aligned siphon flow, where the larger field strength at the inner footpoints together with the lower temperature in the penumbra causes the necessary gas pressure difference relative to the outer footpoints in the hotter quiet Sun with lower magnetic field strength. The IEF connects to magnetic field lines that are not, like in the case of the regular Evershed flow, but which continue upward into the chromosphere, indicating an “uncombed” penumbral structure.
Effect on Cardiac Function of Longstanding Juvenile-onset Mixed Connective Tissue Disease: A Controlled Study
Authors: Witczak Birgit Nomeland , Hetlevik Siri Opsahl , Sanner Helga , Barth Zoltan , Schwartz Thomas , Flatø Berit , Lilleby Vibke , Sjaastad Ivar 
Published: March 2019

Objective.To assess cardiac function in patients with juvenile mixed connective tissue disease (JMCTD) compared to matched controls, and to investigate possible associations between cardiac impairment and disease variables and cardiovascular risk factors.Methods.Fifty JMCTD patients (86% female) examined median 14.9 (6.6–23.0) years after disease onset were compared with 50 age- and sex-matched controls. Electrocardiogram and echocardiography [including e′ as a marker for diastolic dysfunction and long-axis strain (LAS) and left ventricular (LV) ejection fraction (EF) as markers of systolic function] were performed. LV dysfunction (LVD) was defined as low EF, low LAS, or low e′. Right ventricular function was assessed with tricuspid annular plane systolic excursion (TAPSE). Cardiovascular risk factors and disease variables were assessed.Results.LVD was found in 16% of patients and 4% of controls (p = 0.035). EF and LAS were lower in patients compared to controls (6% lower, p < 0.001, and 4% lower, p = 0.044, respectively). TAPSE was 8% lower in patients versus controls (p = 0.008). No patients had signs of pulmonary hypertension. Patients had longer corrected QT time than controls (p = 0.012). LVD was associated with higher levels of apolipoprotein B, higher disease activity measured by physician’s global assessment, longer prednisolone treatment, and more organ damage assessed with the Myositis Damage Index.Conclusion.Patients with JMCTD had impaired left and right ventricular function compared to matched controls after median 15 years disease duration. High disease activity and longer treatment with prednisolone were factors associated with LVD.
Assessing Associations of Synovial Perfusion, Cartilage Quality, and Outcome in Rheumatoid Arthritis Using Dynamic Contrast-enhanced Magnetic Resonance Imaging
Authors: Sewerin Philipp , Schleich Christoph , Brinks Ralph , Müller-Lutz Anja , Fichter Florian , Eichner Markus , Schneider Matthias , Ostendorf Benedikt , Vordenbäumen Stefan 
Published: March 2019

Objective.To assess associations of synovial perfusion, cartilage quality, and outcome in rheumatoid arthritis (RA).Methods.Synovial perfusion and cartilage quality were assessed by dynamic contrast-enhanced magnetic resonance imaging in metacarpophalangeal joints of 28 treatment-naive patients with RA at baseline and at 3 and 6 months after methotrexate. Analysis was by linear mixed modeling.Results.Synovial perfusion variables were associated with remission (p < 0.05) and cartilage quality (p < 0.004). Maximum synovial enhancement was associated to European League Against Rheumatism response (p < 0.05). Synovial perfusion improved in nonresponders over time (p < 0.05).Conclusion.Synovial perfusion relates to remission, response, and cartilage quality in a cohort of therapy-naive patients with early RA.
Effects of Sarilumab on Rheumatoid Arthritis as Reported by Patients Using the Rheumatoid Arthritis Impact of Disease Scale
Authors: Gossec Laure , Strand Vibeke , Proudfoot Clare , Chen Chieh-I , Guillonneau Sophie , Kimura Toshio , van Hoogstraten Hubert , Mangan Erin , Reaney Matthew 
Published: March 2019

Objective.We evaluated the effect of sarilumab on patient-perceived impact of rheumatoid arthritis (RA) using the 7-domain RA Impact of Disease (RAID) scale.Methods.Two phase III, randomized, controlled trials of sarilumab in patients with active, longstanding RA were analyzed: (1) sarilumab 150 mg and 200 mg every 2 weeks plus conventional synthetic disease-modifying antirheumatic drugs (+csDMARD) versus placebo + csDMARD [TARGET (NCT01709578)]; and (2) sarilumab 200 mg versus adalimumab (ADA) 40 mg monotherapy [MONARCH (NCT02332590)]. Least-squares mean (LSM) differences in RAID total score (range 0–10) and 7 key RA symptoms, including pain and fatigue (baseline to Weeks 12 and 24), were compared. “Responders” by RAID total score were defined by improvements from baseline ≥ minimal clinically important difference (MCID), and ≥ patient-acceptable symptom-state (PASS) at endpoint.Results.Sarilumab 150 mg and 200 mg + csDMARD were nominally superior (p < 0.05) versus placebo + csDMARD and 200 mg sarilumab versus ADA 40 mg in LSM differences for RAID total score at weeks 12 (−0.93 and −1.13; −0.49, respectively) and 24 (−0.75 and −1.01; −0.78), and all effects of RA (except functional impairment in MONARCH Week 12). Effects were greater in physical domains (e.g., pain) than mental domains (e.g., emotional well-being). More patients receiving sarilumab versus placebo or ADA reported improvements ≥ MCID and PASS in total RAID scores at both assessments.Conclusion.Based on the RAID, sarilumab + csDMARD or as monotherapy reduced the effect of RA on patients’ lives to a greater extent than placebo + csDMARD or ADA monotherapy. (ClinicalTrials.gov: NCT01709578 and NCT02332590)