bluuebunny/crossref_metadata_2025_split huggingface dataset:
Understanding the link between circumferential dikes and eruptive fissures around calderas based on numerical and analog models
Authors: Corbi Fabio , Rivalta Eleonora , Pinel Virginie , Maccaferri Francesco , Acocella Valerio 
Published: June 2016

AbstractActive calderas are seldom associated with circumferential eruptive fissures, but eroded magmatic complexes reveal widespread circumferential dikes. This suggests that, while the conditions to emplace circumferential dikes are easily met, mechanisms must prevent them from reaching the surface. We explain this discrepancy with experiments of air injection into gelatin shaped as a volcano with caldera. Analog dikes show variable deflection, depending on the competition between overpressure, Pe, and topographic unloading, Pl; when Pl/Pe = 4.8–5.3, the dikes propagate orthogonal to the least compressive stress. Due to the unloading, they become circumferential and stall below the caldera rim; buoyancy is fundamental for the further rise and circumferential fissure development. Numerical models quantitatively constrain the stress orientation within the gelatin, explaining the observed circumferential dikes. Our results explain how dikes propagate below the rim of felsic and mafic calderas, but only in the latter they are prone to feed circumferential fissures.
Interannual similarity in the Martian atmosphere during the dust storm season
Authors: Kass D. M. , Kleinböhl A. , McCleese D. J. , Schofield J. T. , Smith M. D. 
Published: June 2016

AbstractWe find that during the dusty season on Mars (southern spring and summer) of years without a global dust storm there are three large regional‐scale dust storms. The storms are labeled A, B, and C in seasonal order. This classification is based on examining the zonal mean 50 Pa (∼25 km) daytime temperature retrievals from TES/MGS and MCS/MRO over 6 Mars Years. Regional‐scale storms are defined as events where the temperature exceeds 200 K. Examining the MCS dust field at 50 Pa indicates that warming in the Southern Hemisphere is dominated by direct heating, while northern high latitude warming is a dynamical response. A storms are springtime planet encircling Southern Hemisphere events. B storms are southern polar events that begin near perihelion and last through the solstice. C storms are southern summertime events starting well after the end of the B storm. C storms show the most interannual variability.
More stable yet bimodal geodynamo during the Cretaceous superchron?
Authors: Lhuillier Florian , Gilder Stuart A. , Wack Michael , He Kuang , Petersen Nikolai , Singer Brad S. , Jicha Brian R. , Schaen Allen J. , Colon Dylan 
Published: June 2016

AbstractWe report palaeomagnetic and40Ar/39Ar dating results from two sequences of basaltic lava flows deposited at the same locality in western China, yet separated in time by ~50 Myr: one set lies within the Cretaceous normal superchron at 112–115 Ma and a second at 59–70 Ma spanning the Cretaceous‐Palaeogene boundary. We find that magnetic field directions during the superchron exhibit bimodal populations: one with inclinations representative of a dipolar field and another with shallow inclinations that could reflect a more complex, multipolar field. However, the time‐dependent variability in field directions was 50% lower during the superchron than after, which implies greater field stability during the superchron. Our results suggest that episodes of less dipolar field behavior occurred within the Cretaceous superchron and raise the question whether a second, more multipolar, field state is more persistent than previously thought.
Crustal magnetization and the subseafloor structure of the ASHES vent field, Axial Seamount, Juan de Fuca Ridge: Implications for the investigation of hydrothermal sites
Authors: Caratori Tontini Fabio , Crone Timothy J. , de Ronde Cornel E. J. , Fornari Daniel J. , Kinsey James C. , Mittelstaedt Eric , Tivey Maurice 
Published: June 2016

AbstractHigh‐resolution geophysical data have been collected using the Autonomous Underwater Vehicle (AUV) Sentry over the ASHES (Axial Seamount Hydrothermal Emission Study) high‐temperature (~348°C) vent field at Axial Seamount, on the Juan de Fuca Ridge. Multiple surveys were performed on a 3‐D grid at different altitudes above the seafloor, providing an unprecedented view of magnetic data resolution as a function of altitude above the seafloor. Magnetic data derived near the seafloor show that the ASHES field is characterized by a zone of low magnetization, which can be explained by hydrothermal alteration of the host volcanic rocks. Surface manifestations of hydrothermal activity at the ASHES vent field are likely controlled by a combination of local faults and fractures and different lava morphologies near the seafloor. Three‐dimensional inversion of the magnetic data provides evidence of a vertical, pipe‐like upflow zone of the hydrothermal fluids with a vertical extent of ~100 m.
A telescopic and microscopic examination of acceleration in the June 2015 geomagnetic storm: Magnetospheric Multiscale and Van Allen Probes study of substorm particle injection
Authors: Baker D. N. , Jaynes A. N. , Turner D. L. , Nakamura R. , Schmid D. , Mauk B. H. , Cohen I. J. , Fennell J. F. , Blake J. B. , Strangeway R. J. , Russell C. T. , Torbert R. B. , Dorelli J. C. , Gershman D. J. , Giles B. L. , Burch J. L. 
Published: June 2016

AbstractAn active storm period in June 2015 showed that particle injection events seen sequentially by the four (Magnetospheric Multiscale) MMS spacecraft subsequently fed the enhancement of the outer radiation belt observed by Van Allen Probes mission sensors. Several episodes of significant southward interplanetary magnetic field along with a period of high solar wind speed (Vsw ≳ 500 km/s) on 22 June occurred following strong interplanetary shock wave impacts on the magnetosphere. Key events on 22 June 2015 show that the magnetosphere progressed through a sequence of energy‐loading and stress‐developing states until the entire system suddenly reconfigured at 19:32 UT. Energetic electrons, plasma, and magnetic fields measured by the four MMS spacecraft revealed clear dipolarization front characteristics. It was seen that magnetospheric substorm activity provided a “seed” electron population as observed by MMS particle sensors as multiple injections and related enhancements in electron flux.
The impact of energetic electron precipitation on mesospheric hydroxyl during a year of solar minimum
Authors: Zawedde Annet Eva , Nesse Tyssøy Hilde , Hibbins Robert , Espy Patrick J. , Ødegaard Linn‐Kristine Glesnes , Sandanger Marit Irene , Stadsnes Johan 
Published: June 2016

AbstractIn 2008 a sequence of geomagnetic storms occurred triggered by high‐speed solar wind streams from coronal holes. Improved estimates of precipitating fluxes of energetic electrons are derived from measurements on board the NOAA/POES 18 satellite using a new analysis technique. These fluxes are used to quantify the direct impact of energetic electron precipitation (EEP) during solar minimum on middle atmospheric hydroxyl (OH) measured from the Aura satellite. During winter, localized longitudinal density enhancements in the OH are observed over northern Russia and North America at corrected geomagnetic latitudes poleward of 55°. Although the northern Russia OH enhancement is closely associated with increased EEP at these longitudes, the strength and location of the North America enhancement appear to be unrelated to EEP. This OH density enhancement is likely due to vertical motion induced by atmospheric wave dynamics that transports air rich in atomic oxygen and atomic hydrogen downward into the middle atmosphere, where it plays a role in the formation of OH. In the Southern Hemisphere, localized enhancements of the OH density over West Antarctica can be explained by a combination of enhanced EEP due to the local minimum in Earth's magnetic field strength and atmospheric dynamics. Our findings suggest that even during solar minimum, there is substantial EEP‐driven OH production. However, to quantify this effect, a detailed knowledge of where and when the precipitation occurs is required in the context of the background atmospheric dynamics.
The Pickup Ion Composition Spectrometer
Authors: Gilbert Jason A. , Zurbuchen Thomas H. , Battel Steven 
Published: June 2016

AbstractObservations of newly ionized atoms that are picked up by the magnetic field in the expanding solar wind contain crucial information about the gas or dust compositions of their origins. The pickup ions (PUIs) are collected by plasma mass spectrometers and analyzed for their density, composition, and velocity distribution. In addition to measurements of PUIs from planetary sources, in situ measurements of interstellar gas have been made possible by spectrometers capable of differentiating between heavy ions of solar and interstellar origin. While important research has been done on these often singly charged ions, the instruments that have detected many of them were designed for the energy range and ionic charge states of the solar wind and energized particle populations, and not for pickup ions. An instrument optimized for the complete energy and time‐of‐flight characterization of pickup ions will unlock a wealth of data on these hitherto unobserved or unresolved PUI species. The Pickup Ion Composition Spectrometer (PICSpec) is one such instrument and can enable the next generation of pickup ion and isotopic mass composition measurements. By combining a large‐gap time‐of‐flight–energy sensor with a −100 kV high‐voltage power supply for ion acceleration, PUIs will not only be above the detection threshold of traditional solid‐state energy detectors but also be resolved sufficiently in time of flight that isotopic composition can be determined. This technology will lead to a new generation of space composition instruments, optimized for measurements of both heliospheric and planetary pickup ions.
Variance anisotropy in compressible 3‐D MHD
Authors: Oughton S. , Matthaeus W. H. , Wan Minping , Parashar Tulasi 
Published: June 2016

AbstractWe employ spectral method numerical simulations to examine the dynamical development of anisotropy of the variance, or polarization, of the magnetic and velocity field in compressible magnetohydrodynamic (MHD) turbulence. Both variance anisotropy and spectral anisotropy emerge under influence of a large‐scale mean magnetic field B0; these are distinct effects, although sometimes related. Here we examine the appearance of variance parallel to B0, when starting from a highly anisotropic state. The discussion is based on a turbulence theoretic approach rather than a wave perspective. We find that parallel variance emerges over several characteristic nonlinear times, often attaining a quasi‐steady level that depends on plasma beta. Consistency with solar wind observations seems to occur when the initial state is dominated by quasi‐two‐dimensional fluctuations.
Propagation of small size magnetic holes in the magnetospheric plasma sheet
Authors: Yao S. T. , Shi Q. Q. , Li Z. Y. , Wang X. G. , Tian A. M. , Sun W. J. , Hamrin M. , Wang M. M. , Pitkänen T. , Bai S. C. , Shen X. C. , Ji X. F. , Pokhotelov D. , Yao Z. H. , Xiao T. , Pu Z. Y. , Fu S. Y. , Zong Q. G. , De Spiegeleer A. , Liu W. , Zhang H. , Rème H. 
Published: June 2016

AbstractMagnetic holes (MHs), characteristic structures where the magnetic field magnitude decreases significantly, have been frequently observed in space plasmas. Particularly, small size magnetic holes (SSMHs) which the scale is less than or close to the proton gyroradius are recently detected in the magnetospheric plasma sheet. In this study of Cluster observations, by the timing method, the minimum directional difference (MDD) method, and the spatiotemporal difference (STD) method, we obtain the propagation velocity of SSMHs in the plasma flow frame. Furthermore, based on electron magnetohydrodynamics (EMHD) theory we calculate the velocity, width, and depth of the electron solitary wave and compare it to SSMH observations. The result shows a good accord between the theory and the observation.
Future aerosol reductions and widening of the northern tropical belt
Authors: Allen Robert J. , Ajoku Osinachi 
Published: June 2016

AbstractObservations show that the tropical belt has widened over the past few decades, a phenomenon associated with poleward migration of subtropical dry zones and large‐scale atmospheric circulation. Although part of this signal is related to natural climate variability, studies have identified an externally forced contribution primarily associated with greenhouse gases (GHGs) and stratospheric ozone loss. Here we show that the increase in aerosols over the twentieth century has led to contraction of the northern tropical belt, thereby offsetting part of the widening associated with the increase in GHGs. Over the 21st century, however, when aerosol emissions are projected to decrease, the effects of aerosols and GHGs reinforce one another, both contributing to widening of the northern tropical belt. Models that have larger aerosol forcing, by including aerosol indirect effects on cloud albedo and lifetime, yield significantly larger Northern Hemisphere (NH) tropical widening than models with direct aerosol effects only. More targeted simulations show that future reductions in aerosols can drive NH tropical widening as large as greenhouse gases, and idealized simulations show the importance of NH midlatitude aerosol forcing. Mechanistically, the 21st century reduction in aerosols peaks near 40°N, which results in a corresponding maximum increase in surface solar radiation, NH midlatitude tropospheric warming amplification, and a poleward shift in the latitude of maximum baroclinicity, implying a corresponding shift in atmospheric circulation. If models with aerosol indirect effects better represent the real world, then future aerosol changes are likely to be an important—if not dominant—driver of NH tropical belt widening.
A mathematical framework for analysis of water tracers: Part 1: Development of theory and application to the preindustrial mean state
Authors: Singh H. A. , Bitz C. M. , Nusbaumer J. , Noone D. C. 
Published: June 2016

AbstractA new matrix operator framework is developed to analyze results from climate modeling studies that employ numerical water tracers (WTs), which track the movement of water in the aerial hydrological cycle from evaporation to precipitation. Model WT output is related to the fundamental equation of hydrology, and the moisture flux divergence is subdivided into the divergence of locally evaporated moisture and the convergence of remotely evaporated moisture. The formulation also separates locally and remotely sourced precipitation. The remote contribution (also the remote moisture convergence) may be further subdivided into zonal, meridional, intrabasin, and interbasin parts. This framework is applied to the preindustrial climate as simulated by a global climate model in which water has been tagged in 10° latitude bands in each of the major ocean basins, and in which each major land mass has been tagged separately. New insights from the method reveal fundamental differences between the major ocean basins in locally sourced precipitation, remotely sourced precipitation, and their relative partitioning. Per unit area, the subtropical Atlantic is the largest global moisture source, providing precipitable water to adjacent land areas and to the eastern Pacific tropics while retaining the least for in situ precipitation. Subtropical moisture is least divergent over the Pacific, which is the smallest moisture source (per unit area) for global land areas. Basins also differ in how subtropical moisture is partitioned between tropical, midlatitude, and land regions. Part II will apply this framework to hydrological cycle perturbations due to CO2 doubling.
High‐Valent Pentamethylcyclopentadienylcobalt(III) or ‐iridium(III)‐Catalyzed CH Annulation with Alkynes: Synthesis of Heterocyclic Quaternary Ammonium Salts
Authors: Lao Ye‐Xing , Zhang Shang‐Shi , Liu Xu‐Ge , Jiang Chun‐Yong , Wu Jia‐Qiang , Li Qingjiang , Huang Zhi‐Shu , Wang Honggen 
Published: June 2016

AbstractNine types of diversely fused heterocyclic quaternary ammonium salts were constructed through an oxidative CH annulation reaction. Both high‐valent pentamethylcyclopentadienylcobalt(III) and pentamethylcyclopentadienyliridium(III) were found to be effective as catalyst for this reaction. Broad substrate scope and good functional group tolerance were observed.magnified image
Palladium‐Catalyzed Oxidative Cyclization for the Synthesis of Indolyl/Pyrrolyl 3‐Phosphonates
Authors: Mishra Aniket , Deb Indubhusan 
Published: June 2016

AbstractImino‐/enaminophosphonates derived from amines and diethyl phenacyl phosphonates undergo oxidative cyclization via CH bond activation catalyzed by palladium chloride to provide a convenient route for the synthesis of substituted indol‐3‐yl and pyrrol‐3‐yl phosphonates.magnified image
A systematic literature review of the effectiveness of occupational health and safety regulatory enforcement
Authors: Tompa Emile , Kalcevich Christina , Foley Michael , McLeod Chris , Hogg‐Johnson Sheilah , Cullen Kim , MacEachen Ellen , Mahood Quenby , Irvin Emma 
Published: June 2016

BackgroundWe aimed to determine the strength of evidence on the effectiveness of legislative and regulatory policy levers in creating incentives for organizations to improve occupational health and safety processes and outcomes.MethodsA systematic review was undertaken to assess the strength of evidence on the effectiveness of specific policy levers using a “best‐evidence” synthesis approach.ResultsA structured literature search identified 11,947 citations from 13 peer‐reviewed literature databases. Forty‐three studies were retained for synthesis. Strong evidence was identified for three out of nine clusters.ConclusionsThere is strong evidence that several OHS policy levers are effective in terms of reducing injuries and/or increasing compliance with legislation. This study adds to the evidence on OHS regulatory effectiveness from an earlier review. In addition to new evidence supporting previous study findings, it included new categories of evidence–compliance as an outcome, nature of enforcement, awareness campaigns, and smoke‐free workplace legislation. Am. J. Ind. Med. 59:919–933, 2016. © 2016 Wiley Periodicals, Inc.
An evaluation of invasive fungal sinusitis outcomes with subsite analysis and use of frozen section analysis
Authors: Foshee James , Luminais Chris , Casey James , Farag Alexander , Prestipino Anthony , Iloreta Alfred Marc , Nyquist Gurston , Rosen Marc 
Published: June 2016

BackgroundInvasive fungal sinusitis (IFS) is an aggressive mycosis of the nasal cavity with frequent extension to adjacent structures. Occurring more commonly in immunocompromised individuals, prognosis is typically poor despite aggressive treatment. This study aims to examine postoperative outcomes and survival of a cohort of fungal sinusitis patients at an academic center, as well as identify causes of death in IFS patients.MethodsThis study was a retrospective chart review of patient charts and departmental records, yielding patient demographics, medical and surgical treatments, pathology records, and outcomes data.ResultsTwenty‐seven patients were identified from departmental records between 1998 and 2014. Twenty‐one patients presented with Mucor infections, whereas the remaining 6 patients had Aspergillus. All patients were immunocompromised: diabetes (n = 14) and hematologic malignancy (n = 13). Three patients had multiple causes of immunosuppression. Most commonly involved subsites were the maxillary, ethmoid, and sphenoid sinuses. Nasal septum involvement was independently associated with mortality (p < 0.01). Overall mortality was 57.7% within 1 year, although 66.7% of fatalities occurred within 1 month of diagnosis.ConclusionOverall survival for IFS remains poor. Widespread disease and nasal septum involvement were associated with a negative clinical course. Early identification and aggressive surgical and antifungal therapy is warranted. Even despite intense therapy, comorbid conditions and drug toxicity increase mortality and complicate the clinical course.
Ultrathin buffer layer at organic/organic interface for managing the recombination profile in organic light‐emitting diodes: Metal versus dielectric buffer
Authors: Kalhor Davood , Mohajerani Ezeddin , HashemiPour Omid , SalehiKian Akram , Shojaeifar Mohsen , Rasoul Babaei Mohammad 
Published: June 2016

ABSTRACTWe report on the utilization of an ultrathin buffer layer at the organic/organic (O/O) interface to enhance device efficiency in organic light‐emitting diodes. Two different kinds of buffer layers are examined: metal and dielectric. It is shown that employment of an ultrathin Ag layer with a thickness of 1–2 nm enhances the device performance, while a MgF2 dielectric buffer cannot affect the device properties considerably. In particular, the turn‐on voltage of the device with an appropriate buffer layer is reduced about 3 V, its current efficiency increases by a factor of more than three, and the power efficiency increases by a factor of more than five in comparison to the control device when a Ag buffer layer is introduced at the O/O interface. By employment of the buffer layer at the interface, an accumulation of current carriers appears within the device that redistribute the recombination profile toward the interior part of the emissive layer. Also, morphological examinations reveal that distinguishable phase segregation occurs in the blend of the hole‐transport layer. In particular, the polymer component remains at the surface and facilitates the hole transport into the successive layers. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43894.
Quantifying and comparing the selectivity for crosslink scission in mechanical and mechanochemical devulcanization processes
Authors: Edwards Devon William , Danon Bart , van der Gryp Percy , Görgens Johann Ferdinand 
Published: June 2016

ABSTRACTDevulcanization processes have potential to increase the economic value of ground tire rubber (GTR) derived from waste tires, although the chemistry of the devulcanization process is still poorly understood. This article presents a method, based on sol extraction and swelling measurements, for quantifying the selectivity for crosslink scission over main chain scission, and applies it to extrusion‐based mechanical and mechanochemical devulcanization processes at various operating conditions. The mechanochemical devulcanization process, using diphenyl disulfide and process oil, resulted in a higher selectivity for crosslink scission than the mechanical devulcanization process. Furthermore, it was shown that the process oil, along with lower reaction temperature, in the mechanochemical devulcanization process was responsible for the increased selectivity, rather than the presence of diphenyl disulfide. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43932.