bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oxidation of manganese in an ancient aquifer, Kimberley formation, Gale crater, Mars
Authors: Lanza Nina L. , Wiens Roger C. , Arvidson Raymond E. , Clark Benton C. , Fischer Woodward W. , Gellert Ralf , Grotzinger John P. , Hurowitz Joel A. , McLennan Scott M. , Morris Richard V. , Rice Melissa S. , Bell James F. , Berger Jeffrey A. , Blaney Diana L. , Bridges Nathan T. , Calef Fred , Campbell John L. , Clegg Samuel M. , Cousin Agnes , Edgett Kenneth S. , Fabre Cécile , Fisk Martin R. , Forni Olivier , Frydenvang Jens , Hardy Keian R. , Hardgrove Craig , Johnson Jeffrey R. , Lasue Jeremie , Le Mouélic Stéphane , Malin Michael C. , Mangold Nicolas , Martìn‐Torres Javier , Maurice Sylvestre , McBride Marie J. , Ming Douglas W. , Newsom Horton E. , Ollila Ann M. , Sautter Violaine , Schröder Susanne , Thompson Lucy M. , Treiman Allan H. , VanBommel Scott , Vaniman David T. , Zorzano Marìa‐Paz 
Published: June 2016

AbstractThe Curiosity rover observed high Mn abundances (>25 wt % MnO) in fracture‐filling materials that crosscut sandstones in the Kimberley region of Gale crater, Mars. The correlation between Mn and trace metal abundances plus the lack of correlation between Mn and elements such as S, Cl, and C, reveals that these deposits are Mn oxides rather than evaporites or other salts. On Earth, environments that concentrate Mn and deposit Mn minerals require water and highly oxidizing conditions; hence, these findings suggest that similar processes occurred on Mars. Based on the strong association between Mn‐oxide deposition and evolving atmospheric dioxygen levels on Earth, the presence of these Mn phases on Mars suggests that there was more abundant molecular oxygen within the atmosphere and some groundwaters of ancient Mars than in the present day.
Transformations of landscape and peat‐forming ecosystems in response to late Holocene climate change in the western Antarctic Peninsula
Authors: Yu Zicheng , Beilman David W. , Loisel Julie 
Published: June 2016

AbstractWe used subfossil mosses and peats to document changes in regional climate, cryosphere, and terrestrial ecosystems in the western Antarctic Peninsula at ~65°S latitude. We find that most peat forming ecosystems have initiated since 2800 cal B.P., in response to warmer summers and increasing summer insolation. The period at 900–600 cal B.P. was coldest as indicated by ice advance, abundance of kill ages from ice‐entombed mosses exposed recently from retreating glacial ice, and apparent gap in peatbank initiation. Furthermore, the discovery of a novel Antarctic hairgrass (Deschampsia antarctica) peatland at 2300–1200 cal B.P. from the mainland Antarctic Peninsula suggests a much warmer climate than the present. A warming and wetting climate in the 1980s caused very high carbon accumulation in a Polytrichum strictum moss peatbank. Our results document dramatic transformations of landscape and ecosystems in response to past warmer climate, providing a telltale sign for what may come in the future.
Seasonal mean temperature changes control future heat waves
Authors: Argüeso Daniel , Di Luca Alejandro , Perkins‐Kirkpatrick Sarah E. , Evans Jason P. 
Published: June 2016

AbstractIncreased temperature will result in longer, more frequent, and more intense heat waves. Changes in temperature variability have been deemed necessary to account for future heat wave characteristics. However, this has been quantified only in Europe and North America, while the rest of the globe remains unexplored. Using late century global climate projections, we show that annual mean temperature increases is the key factor defining heat wave changes in most regions. We find that commonly studied areas are an exception rather than the standard and the mean climate change signal generally outweighs any influence from variability changes. More importantly, differences in warming across seasons are responsible for most of the heat wave changes and their consideration relegates the contribution of variability to a marginal role. This reveals that accurately capturing mean seasonal changes is crucial to estimate future heat waves and reframes our interpretation of future temperature extremes.
ARTEMIS observations of terrestrial ionospheric molecular ion outflow at the Moon
Authors: Poppe A. R. , Fillingim M. O. , Halekas J. S. , Raeder J. , Angelopoulos V. 
Published: June 2016

AbstractThe Acceleration, Reconnection, Turbulence, and Electrodynamics of the Moon's Interaction with the Sun (ARTEMIS) spacecraft observes outflowing molecular ionospheric ions at lunar distances in the terrestrial magnetotail. The heavy ion fluxes are observed during geomagnetically disturbed times and consist of mainly molecular species (
, NO+, and
, approximately masses 28–32 amu) on the order of 105–106 cm−2 s−1 at nearly identical velocities as concurrently present protons. By performing backward particle tracing in time‐dependent electromagnetic fields from the magnetohydrodynamic Open Global Geospace Circulation Model of the terrestrial magnetosphere, we show that the ions escape the inner magnetosphere through magnetopause shadowing near noon and are subsequently accelerated to common velocities down the low‐latitude boundary layer to lunar distances. At the Moon, the observed molecular ion outflow can sputter significant fluxes of neutral species into the lunar exosphere while also delivering nitrogen and oxygen to the lunar volatile inventory.
The response of high‐impact blocking weather systems to climate change
Authors: Kennedy Daniel , Parker Tess , Woollings Tim , Harvey Benjamin , Shaffrey Len 
Published: June 2016

AbstractMidlatitude weather and climate are dominated by the jet streams and associated eastward moving storm systems. Occasionally, however, these are blocked by persistent anticyclonic regimes known as blocking. Climate models generally predict a small decline in blocking frequency under anthropogenic climate change. However, confidence in these predictions is undermined by, among other things, a lack of understanding of the physical mechanisms underlying the change. Here we analyze blocking (mostly in the Euro‐Atlantic sector) in a set of sensitivity experiments to determine the effect of different parts of the surface global warming pattern. We also analyze projected changes in the impacts of blocking such as temperature extremes. The results show that enhanced warming both in the tropics and over the Arctic act to strengthen the projected decline in blocking. The tropical changes are more important for the uncertainty in projected blocking changes, though the Arctic also affects the temperature anomalies during blocking.
Pressure and ion composition boundaries at Mars
Authors: Xu Shaosui , Liemohn Michael W. , Dong Chuanfei , Mitchell David L. , Bougher Stephen W. , Ma Yingjuan 
Published: June 2016

AbstractThis study analyzes results from a multifluid MHD simulation to investigate the shape and structure of the pressure and composition boundaries at Mars, which can provide physical insight for the observational analysis. These boundaries are examined via the unity contours and gradients of the plasma β, as well as β∗, which includes the dynamic pressure in the numerator, and the ion mass and number density ratios. It is found that unity contours are well aligned with the gradient extrema, indicating that the unity contour is a topological boundary. In addition, these two transitions of pressure and composition are of a thickness of 0.05–0.1 RM near the subsolar region to 1–1.5 RM in the tail. The comparison of the pressure and composition boundaries indicates that the two are very similar and that not only the plasma sheet but also the full volume of the lobes are dominated by planetary ions. It suggests that the tail escape for ions not only concentrates in the central plasma sheet but also the magnetic lobes. It is also worthy pointing out that the ion number density ratio unity contour is found to be systematically smaller than other unity boundaries, which calls for attention when the ion number density is used to identify such boundaries. Finally, the comparison between the boundaries of this study and two analytical fittings is carried out. We found a good agreement with the Vignes fitting, with little flaring in the tail, in contrast to a larger flaring angle from the Trotignon fitting.
High‐velocity frictional strength of Longmenshan fault gouge and its comparison with an estimate of friction from the temperature anomaly in WFSD‐1 drill hole
Authors: Togo Tetsuhiro , Yao Lu , Ma Shengli , Shimamoto Toshihiko 
Published: June 2016

AbstractThis paper addresses the issue of whether high‐velocity friction experiments yield frictional strengths of fault materials that are consistent with the level of friction estimated from the postseismic temperature anomaly measured across a coseismic fault zone. Experiments were conducted on gouge (composed of quartz, dolomite, illite, albite, and other clay minerals), collected from a large outcrop of the Yingxiu‐Beichuan fault zone and from Wenchuan Earthquake Fault Scientific Drilling project hole‐1 drill cores in Hongkou, Sichuan Province, China. This fault is a major fault of the Longmenshan fault system that caused the 2008 Mw7.9 Wenchuan earthquake. All experiments revealed dramatic weakening at high velocities with peak friction coefficient μp of 0.07~0.35 and steady state friction coefficient μss of 0.02~0.15 for wet gouge, as compared with μp = 0.49~0.86 and μss = 0.12~0.21 for dry gouge. The average friction coefficients over a displacement of 5.5 m (coseismic displacement) extrapolated to the normal stress in the fault zones are 0.1~0.05 and 0.06~0.03 for dry and wet gouges, respectively. The average friction coefficients of dry and wet gouges are within the upper and lower bounds of friction coefficients estimated from the temperature profiles, and there are overall agreements between the two sets of data that are completely independent. Dry and wet gouges are characterized by highly sheared slip zones often forming overlapping slip‐zone structures and by broad shear zones, respectively. Wet gouge textures are perhaps closer to those of natural fault zone, but repeated slip experiments are needed to determine the textural evolution of wet gouge.
The combined effect of transient wind‐driven upwelling and eddies on vertical nutrient fluxes and phytoplankton dynamics along Ningaloo Reef, Western Australia
Authors: Zhang Zhenlin , Lowe Ryan , Ivey Greg , Xu Jiangtao , Falter James 
Published: June 2016

AbstractWe investigate the influence of wind stresses, stratification, and coastal mesoscale eddies on upwelling intensity, vertical nutrient fluxes, and phytoplankton biomass on the continental shelf off Ningaloo Reef in northwestern Australia during an austral spring‐summer period. A three‐dimensional (3‐D) hydrodynamic model, ROMS (Regional Ocean Modeling System), was coupled with a four‐component nitrogen‐based biogeochemical NPZD model (Nitrogen Phytoplankton Zooplankton Detritus) to resolve the shelf circulation as well as the coupled nutrient and phytoplankton dynamics within a broad shelf region surrounding Ningaloo Reef. The simulated currents, temperatures, and chlorophyll a concentrations generally agreed well with both the remotely sensed satellite images and observational data collected during a field experiment from September to November 2010. Scenario tests for an individual wind‐driven upwelling event under a variety of hypothetical physical forcing conditions showed that shelf currents and biogeochemical variables were largely a function of wind stress and stratification. However, the functional relationships derived from this single wind event could not be extrapolated to other periods of the upwelling season, due to the additional influence of 3‐D mesoscale processes on the shelf. The presence, intensification, and propagation of a coastal anticyclonic eddy during the study period strongly influenced the spatial and temporal variations in nutrient profiles, which in turn caused fluctuations in vertical nutrient fluxes that were largely independent of wind stress. These results emphasize that it is necessary to fully capture the 3‐D details of the mesoscale and submesoscale coastal dynamics to properly predict upwelling‐induced coastal phytoplankton dynamics in eddy‐intensive shelf regions such as Ningaloo Reef.
Representing 3‐D cloud radiation effects in two‐stream schemes: 1. Longwave considerations and effective cloud edge length
Authors: Schäfer Sophia A. K. , Hogan Robin J. , Klinger Carolin , Chiu J. Christine , Mayer Bernhard 
Published: June 2016

AbstractCurrent weather and climate models neglect 3‐D radiative transfer through cloud sides, which can change the cloud radiative effect (CRE) significantly. This two‐part paper describes the development of the SPeedy Algorithm for Radiative TrAnsfer through CloUd Sides (SPARTACUS) to capture these effects efficiently in a two‐stream radiation scheme for use in global models. The present paper concerns the longwave spectral region, where not much work has been done previously, although the limited previous work has suggested that radiative transfer through cloud sides increases the longwave surface CRE of shallow cumulus by around 30%. To assist the development of a longwave capability for SPARTACUS, we use a reference case of an isolated, isothermal, optically thick, cubic cloud in vacuum, for which 3‐D effects increase CRE by exactly 200%. It is shown that for any cloud shape, the 3‐D effect can be represented in SPARTACUS provided that correct account is made for (1) the effective zenith angle of diffuse radiation emitted from a cloud, (2) the spatial distribution of fluxes in the cloud, (3) cloud clustering that enhances the interception of emitted radiation by neighboring clouds, and (4) radiative smoothing leading to the effective cloud edge length being less than the measured value. We find empirically that the circumference of an ellipse fitted to a horizontal cross section through a cumulus cloud provides a good estimate of the radiatively effective cloud edge length, which provides some guidance to how cloud observations could be analyzed to extract their most important properties for radiation.
Large‐eddy simulation of biogenic VOC chemistry during the DISCOVER‐AQ 2011 campaign
Authors: Li Yang , Barth Mary C. , Chen Gao , Patton Edward G. , Kim Si‐Wan , Wisthaler Armin , Mikoviny Tomas , Fried Alan , Clark Richard , Steiner Allison L. 
Published: June 2016

AbstractBiogenic volatile organic compounds (BVOCs) are oxidized quickly in the atmosphere to form oxygenated VOC (OVOC) and play crucial roles in the formation of ozone and secondary organic aerosols. We use the National Center for Atmospheric Research's large‐eddy simulation model and Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality 2011 flight data to understand the role of boundary layer turbulence on the atmospheric chemistry of key BVOC species and their oxidation products. We simulate three distinct convective environments during the campaign, representing fair weather conditions (case 1: 1 July), a convective event dominated by southwesterly flow (case 2: 11 July), and a polluted event with high temperature and convection (case 3: 29 July). Isoprene segregation is greatest in the lower boundary layer under warm and convective conditions, reaching up to a 10% reduction in the isoprene‐OH reaction rate. Under warm and convective conditions, the BVOC lifetimes lengthen due to increased isoprene emission, elevated initial chemical concentrations, and OH competition. Although turbulence‐driven segregation has less influence on the OVOC species, convection mixes more OVOC into the upper atmospheric boundary layer (ABL) and increases the total OH reactivity. Production and loss rates of ozone above 2 km in all the three cases indicate in situ ozone formation in addition to vertical convective transport of ozone from the surface and aloft, consistent with the increased contribution of OH reactivity from OVOC. Together, these results show that total OH reactivity in the ABL increases under warmer and stronger convective conditions due to enhanced isoprene emission and the OVOC contribution to ozone formation.
RF‐DC converter for HF RFID sensing applications powered by a near‐field loop antenna
Authors: Colella R. , Pasca M. , Catarinucci L. , Tarricone L. , D'Amico S. 
Published: June 2016

AbstractIn this paper, an RF‐DC converter operating at 13.56 MHz (HF radio frequency identification (RFID) frequency band) is presented. Its architecture provides RF to load isolation, reducing the losses due to the reverse saturation current and improving the sensitivity. Fed by a loop antenna, the RF‐DC converter is made by a Dickson's RF‐DC rectifier and an additional Pelliconi's charge pump driven by a fully integrated 50 kHz ring oscillator realized using an application‐specific integrated circuit (ASIC). The input RF signal from the reader is converted to DC supply voltage and stored on a 1 μF capacitor. Mathematical model of the converter is developed and verified through measurements. Silicon prototypes of the ASIC have been realized in 350 nm complementary metal‐oxide semiconductor technology. Measurements have been done on 10 different samples showing an output voltage in the range of 0.5 V–3.11 V in correspondence of an RF input signal power in the range of −19 dBm–0 dBm. These output voltage levels are suitable to power HF RFID sensing platforms and sensor nodes of body sensor networks.
Multiscale pore‐network representation of heterogeneous carbonate rocks
Authors: Pak Tannaz , Butler Ian B. , Geiger Sebastian , van Dijke Marinus I.J. , Jiang Zeyun , Surmas Rodrigo 
Published: June 2016

AbstractA multiscale network integration approach introduced by Jiang et al. (2013) is used to generate a representative pore‐network for a carbonate rock with a pore size distribution across several orders of magnitude. We predict the macroscopic flow parameters of the rock utilising (i) 3‐D images captured by X‐ray computed microtomography and (ii) pore‐network flow simulations. To capture the multiscale pore size distribution of the rock, we imaged four different rock samples at different resolutions and integrated the data to produce a pore‐network model that combines information at several length‐scales that cannot be recovered from a single tomographic image. A workflow for selection of the number and length‐scale of the required input networks for the network integration process, as well as fine tuning the model parameters is presented. Mercury injection capillary‐pressure data were used to evaluate independently the multiscale networks. We explore single‐scale, two‐scale, and three‐scale network models and discuss their representativeness by comparing simulated capillary‐pressure versus saturation curves with laboratory measurements. We demonstrate that for carbonate rocks with wide pore size distributions, it may be required to integrate networks extracted from two or three discrete tomographic data sets in order to simulate macroscopic flow parameters.
Study on Application Properties of Modified Montmorillonite as Phase Change Material for Energy Storage
Authors: Wei Xiaofeng , Wang Jincheng 
Published: June 2016

AbstractNew types of clay materials, I‐PCM and O‐PCM, with good heat storage and release capacity were prepared by the inorganic and organic montmorillonite (MMT) intercalated with phase change material (PCM). The PCM used was the mixture of liquid and solid paraffin. To get an optimal combination regimen, orthogonal experiments of four factors and three levels were used. All samples were examined by differential scanning calorimetry (DSC). Their cyclic endothermic and exothermic phase change latent heat were observed and calculated. Then, the most reasonable and effective experimental conditions were chosen to prepare the I‐PCM and O‐PCM with the best heat storage and release capacity. These clays were then characterized by diffusion‐oozing circle method, thermogravimetric (TG) analysis, scanning electron microscopy (SEM), X‐ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and other testing methods. The diffusion‐oozing circle results showed that O‐PCM was almost extremely stable compared with that of I‐PCM according to the leakage circle. In XRD analysis, expansions of the spacings in the plane were observed for all O‐PCMs. This indicated that the intercalation of surfactants and paraffin molecules in the galleries of MMT was successfully achieved. TG‐DTG analysis of these clays illustrated that all O‐PCMs could be suitable for industrial applications due to their high thermal stability. DSC analysis illustrated that O‐PCM samples possessed a more stable structure together with better heat storage and release capacity compared with that of I‐PCM samples.
Occupational exposure to polycyclic aromatic hydrocarbons: A cross‐sectional study in bars and restaurants in Santiago, Chile
Authors: Muñoz Claudio , Droppelmann Andrea , Erazo Marcia , Aceituno Paulina , Orellana Cecilia , Parro Javiera , Mesias Sthepanie , Marchetti Nella , Navas‐Acien Ana , Iglesias Verónica 
Published: June 2016

ObjectiveTo evaluate indoor polycyclic aromatic hydrocarbon (PAH) concentrations in bars and restaurants and identify the main determinants of airborne PAH concentrations.MethodsThis study included 57 bars/restaurants in Santiago, Chile. PAH concentrations (ng/m3) were measured using photoelectric aerosol sensor equipment (PAS 2000CE model). Nicotine concentrations (μg/m3) were measured using active sampling pumps followed by gas‐chromatography. Linear regression models were used to identify determinants of PAH concentrations.ResultsPAH concentrations were higher in venues that allowed smoking compared to smoke‐free venues. After adjusting, the air PAH concentrations were 1.40 (0.64–3.10) and 3.34 (1.43–7.83) ng/m3 higher for tertiles 2 and 3 of air nicotine compared to the lowest tertile.ConclusionsIn hospitality venues where smoking is allowed, secondhand smoke exposure is a major source of PAHs in the environment. This research further supports the importance of implementing complete smoking bans to protect service industry workers from PAH exposure. Am. J. Ind. Med. 59:887–896, 2016. © 2016 Wiley Periodicals, Inc.
Mortality among workers exposed to toluene diisocyanate in the US polyurethane foam industry: Update and exposure‐response analyses
Authors: Pinkerton Lynne E. , Yiin James H. , Daniels Robert D. , Fent Kenneth W. 
Published: June 2016

BackgroundMortality among 4,545 toluene diisocyante (TDI)‐exposed workers was updated through 2011. The primary outcome of interest was lung cancer.MethodsLife table analyses, including internal analyses by exposure duration and cumulative TDI exposure, were conducted.ResultsCompared with the US population, all cause and all cancer mortality was increased. Lung cancer mortality was increased but was not associated with exposure duration or cumulative TDI exposure. In post hoc analyses, lung cancer mortality was associated with employment duration in finishing jobs, but not in finishing jobs involving cutting polyurethane foam.ConclusionsDermal exposure, in contrast to inhalational exposure, to TDI is expected to be greater in finishing jobs and may play a role in the observed increase in lung cancer mortality. Limitations include the lack of smoking data, uncertainty in the exposure estimates, and exposure estimates that reflected inhalational exposure only. Am. J. Ind. Med. 59:630–643, 2016. Published 2016. This article is a U.S. Government work and is in the public domain in the USA
Iron/S8‐Catalyzed Redox Condensation of o‐Nitroarenes with Arylmethyl Chloride: Synthesis of Benzimidazoles and Benzothiazoles
Authors: Gan Haifeng 
Published: June 2016

AbstractFe/S clusters generated from simple iron salts and sulfur were found to be highly efficient to catalyze the redox condensation reaction between nitroarenes and arylmethyl chlorides in the presence of the base N‐methylpiperidine. The reactions proceeded in moderate‐to‐good yields with good functional tolerance.