bluuebunny/crossref_metadata_2025_split huggingface dataset:
Global Observational Evidence of Strong Linkage Between Dew Point Temperature and Precipitation Extremes
Authors: Ali Haider , Fowler Hayley J. , Mishra Vimal 
Published: November 2018

AbstractUsing global station‐based observations of precipitation, near‐surface air temperature (SAT), and dew point temperature (DPT), we show that the negative scaling relationship found between extreme daily precipitation and SAT over the tropics is associated with the low seasonality in temperature. When using a binning technique or quantile regression, not accounting for seasonality in temperature produces a negative scaling for the majority of stations in the tropics, with higher temperatures associated with smaller precipitation extremes. After removing temperature seasonality, we find that most locations show a positive (median 5.2%/K) scaling with SAT and 96% of global locations exhibit positive (median 6.1%/K) scaling with DPT. Moreover, about 33% (22%) of the locations show super C‐C scaling (higher than 7%/K) with DPT (SAT). Our results show that the impact of warming on extreme precipitation (especially over the tropics) may be higher than previously thought.
Sediment Characterization at the Equatorial Mid‐Atlantic Ridge From P‐to‐S Teleseismic Phase Conversions Recorded on the PI‐LAB Experiment
Authors: Agius M. R. , Harmon N. , Rychert C. A. , Tharimena S. , Kendall J.‐M. 
Published: November 2018

AbstractAccurate marine sediment characteristics, for example, thickness and seismic velocity, are important for constraining sedimentation rates with implications for climate variations and for seismic imaging of deeper structures using ocean bottom seismic deployments. We analyze P‐to‐S seismic phase conversions from the sediment‐crust boundary recorded by the Passive Imaging of the Lithosphere‐Asthenosphere Boundary (PI‐LAB) experiment to infer the sediment thickness across the Mid‐Atlantic Ridge covering 0‐ to 80‐Myr‐old seafloor. We find Pds‐P delay times of 0.04–0.37 s, or 5‐ to 82‐m thickness. Sediment thickness increases with age. Thickness agrees with global estimates for young (<15–20 Myr) seafloor but is thinner on older lithosphere. Our result may represent a lower limit on sediment thickness, given that several of our stations are on topographic highs. The sedimentation rate decrease observed from 5 to 1.2 mm/kyr at ∼10 Myr suggests a recent increase in productivity related to climate change, eolian dust fluxes, and/or biogenic marine activity.
A Statistical Analysis of STEVE
Authors: Gallardo‐Lacourt Bea , Nishimura Y. , Donovan E. , Gillies D. M. , Perry G. W. , Archer W. E. , Nava O. A. , Spanswick E. L. 
Published: November 2018

AbstractThere has been an exciting recent development in auroral research associated with the discovery of a new subauroral phenomenon called STEVE (Strong Thermal Emission Velocity Enhancement). Although STEVE has been documented by amateur night sky watchers for decades, it is as yet an unidentified upper atmosphere phenomenon. Observed first by amateur auroral photographers, STEVE appears as a narrow luminous structure across the night sky over thousands of kilometers in the east‐west direction. In this paper, we present the first statistical analysis of the properties of 28 STEVE events identified using Time History of Events and Macroscale Interactions during Substorms (THEMIS) all‐sky imager and the Redline Emission Geospace Observatory (REGO) database. We find that STEVE occurs about 1 hr after substorm onset at the end of a prolonged expansion phase. On average, the AL index magnitude is larger and the expansion phase has a longer duration for STEVE events compared to subauroral ion drifts or substorms. The average duration for STEVE is about 1 hr, and its latitudinal width is ~20 km, which corresponds to ~¼ of the width of narrow auroral structures like streamers. STEVE typically has an equatorward displacement from its initial location of about 50 km and a longitudinal extent of 2,145 km.
Cooperatives Roles of Dynamics and Topology in Generating the Magnetosphere‐Ionosphere Disturbances: Case of the Theta Aurora
Authors: Tanaka T. , Obara T. , Watanabe M. , Fujita S. , Ebihara Y. , Kataoka R. , Den M. 
Published: November 2018

AbstractTo understand the magnetosphere‐ionosphere (M‐I) disturbances, it is necessary to know the change in the null‐separator structure along with the development of convection. The present paper explains this proposition by taking the case of the theta aurora that occurs after the switch of interplanetary magnetic field By and reveals auroral development inside the polar cap. The interplanetary magnetic field change is followed by the reformation of the null‐separator structure to cause a convection transient and a successive deformation of separatrices inside the magnetosphere, where separatrices separate the space into different volumes that include different types of magnetic field lines, and intersections of separatrices form separators that connect nulls. By the reconnection on the separator, energy inflow occurs from the solar wind to the magnetosphere. Convection driven by this energy transports nulls. In the case of theta aurora, two new nulls on the dayside coexist with two old nulls carried toward the tail by convection. Each set of nulls generates two open‐closed boundaries (separatrices) bounded by separators. Thus, open‐closed boundaries are divide into four parts. Separatrices generated by different sets partially become side by side near the nightside stem limes. The theta aurora is generated at the area corresponding to the low‐latitude side with respect to both of two boundaries. Thus, the occurrence of the theta aurora is a natural consequence of a transition in the null‐separator structure. The present example indicates that the global structure of the magnetosphere is almost decided from the skeleton of nulls.
First Time Estimation of Thermospheric Neutral Density Profiles From Seed Perturbations of ESF Triggering: A Novel Evidence for Ionosphere Thermosphere Coupling
Authors: Manju G. , Aswathy R. P. 
Published: November 2018

AbstractThe present study reveals the coupling between the neutral densities, derived from the Global Ultraviolet Imager satellite and the requisite gravity wave seed perturbations for equatorial spread F occurrence (Manju et al., 2016, https://doi.org/10.1016/j.asr.2015.12.019), derived from the ionosonde data at Trivandrum (8.5°N, 77°E). Further, the relation between the above two parameters is found to have solar flux dependence. The solar activity variations of the coefficients of the empirical relations between the neutral density profiles and the characteristic curves of equatorial spread F triggering have been found out, and general empirical models to estimate the thermospheric neutral densities are established for all seasons. The present model output shows reasonable agreement with the Naval Research Laboratory‐Mass Spectrometer and Incoherent Scatter radar model and Global Ultraviolet Imager‐derived neutral density. The study is relevant since it brings out strong ion‐neutral coupling prevailing in the ionosphere thermosphere system.
Reconstruction of the Electron Diffusion Region of Magnetotail Reconnection Seen by the MMS Spacecraft on 11 July 2017
Authors: Hasegawa H. , Denton R. E. , Nakamura R. , Genestreti K. J. , Nakamura T. K. M. , Hwang K.‐J. , Phan T. D. , Torbert R. B. , Burch J. L. , Giles B. L. , Gershman D. J. , Russell C. T. , Strangeway R. J. , Lindqvist P.‐A. , Khotyaintsev Y. V. , Ergun R. E. , Kitamura N. , Saito Y. 
Published: November 2018

AbstractWe present results from the reconstruction of the electron diffusion region of magnetotail reconnection observed by the Magnetospheric Multiscale (MMS) spacecraft on 11 July 2017. In the event, the conditions were suited for the reconstruction technique, developed by Sonnerup et al. (2016, https://doi.org/10.1002/2016JA022430), that produces magnetic field and electron streamline maps based on a two‐dimensional, time‐independent, inertialess form of electron magnetohydrodynamic equation, assuming an approximately symmetric current sheet and negligible guide magnetic field. For such a two‐dimensional and steady structure, the X line orientation can be estimated from a method based on Ampère's law using single‐spacecraft measurements of the magnetic field and electric current density. Our reconstruction results indicate that although the X point was not captured inside its tetrahedron, MMS approached the X point as close as one electron inertial length ~27 km. The opening angle of the recovered separatrix field line, combined with theory, suggests that the dimensionless reconnection rate was 0.17, which is consistent with the measured reconnection electric field 2–4 mV/m. The stagnation point of the reconstructed electron flow is shifted earthward of the X point by ~90 km, one possible interpretation of which is discussed. The energy conversion rate j · E′ in the electron frame tends to be higher near the stagnation point, consistent with earlier observations and simulations, and is not correlated with the amplitude of broadband electrostatic waves observed in the upper‐hybrid frequency range. The latter suggests that the waves did not contribute to energy dissipation in this particular electron diffusion region.
Interconnectivity Between Volume Transports Through Arctic Straits
Authors: de Boer Agatha M. , Gavilan Pascual‐Ahuir Estanislao , Stevens David P. , Chafik Léon , Hutchinson David K. , Zhang Qiong , Sime Louise C. , Willmott Andrew J. 
Published: November 2018

AbstractArctic heat and freshwater budgets are highly sensitive to volume transports through the Arctic‐Subarctic straits. Here we study the interconnectivity of volume transports through Arctic straits in three models; two coupled global climate models, one with a third‐degree horizontal ocean resolution (High Resolution Global Environmental Model version 1.1 [HiGEM1.1]) and one with a twelfth‐degree horizontal ocean resolution (Hadley Centre Global Environment Model 3 [HadGEM3]), and one ocean‐only model with an idealized polar basin (tenth‐degree horizontal resolution). The two global climate models indicate that there is a strong anticorrelation between the Bering Strait throughflow and the transport through the Nordic Seas, a second strong anticorrelation between the transport through the Canadian Arctic Archipelago and the Nordic Seas transport, and a third strong anticorrelation is found between the Fram Strait and the Barents Sea throughflows. We find that part of the strait correlations is due to the strait transports being coincidentally driven by large‐scale atmospheric forcing patterns. However, there is also a role for fast wave adjustments of some straits flows to perturbations in other straits since atmospheric forcing of individual strait flows alone cannot lead to near mass balance fortuitously every year. Idealized experiments with an ocean model (Nucleus for European Modelling of the Ocean version 3.6) that investigate such causal strait relations suggest that perturbations in the Bering Strait are compensated preferentially in the Fram Strait due to the narrowness of the western Arctic shelf and the deeper depth of the Fram Strait.
A Coupled Glacier‐Hydrology Model and Its Application in Eastern Pamir
Authors: Ren Zheng , Su Fengge , Xu Baiqing , Xie Ying , Kan Baoyun 
Published: November 2018

AbstractAn energy‐balance glacier‐melt scheme was coupled with the Variable Infiltration Capacity hydrology model (VIC‐glacier). The coupled model was setup at 30 m × 30 m grids and applied in the Muji basin in eastern Pamir. The model was validated with field measurements of albedo, glacier mass balance, and river runoff. The VIC‐glacier model showed a good correspondence with the observations in incoming shortwave radiation and albedo, with R2 of 0.70 and 0.32, respectively, during August–October 2012. Simulated glacier mass balance exhibited overall good agreements with the observations in ablation seasons, with R2 of 0.89 and root‐mean‐square error of 162.12 mm w.e. during 2011–2015. The model also reproduced discharge records, with R2 of 0.70–0.84, Nash‐Sutcliffe efficiency of 0.56–0.81, root‐mean‐square error of 0.29–0.45 m3/s, and negative relative error of 13.73–18.76% in melt seasons of 2014–2015. The glaciers in Muji basin had a low mean net radiation of 40 W/m2, large negative latent heat fluxes of −32 W/m2, and low melt energy of −21 W/m2 in ablation seasons, resembling the energy partitioning generally found in continental climates. About 60% of the positive energy supply was consumed by latent heat fluxes on the glaciers in Muji basin, while only about 40% of the positive energy supply was used for melting. Glaciers in the Muji basin experienced a mass balance of −812.18 mm over 2011–2015, corresponding to a water release of 4.42 × 106 m3.The VIC‐glacier model has a good potential of broader utility for the large basins with limited meteorological observations.
Microscopic Observations of Core‐Shell Particle Structure and Implications for Atmospheric Aerosol Remote Sensing
Authors: Unga Florin , Choël Marie , Derimian Yevgeny , Deboudt Karine , Dubovik Oleg , Goloub Philippe 
Published: November 2018

AbstractAlthough atmospheric aerosol particles can have complex heterogeneous microstructure, simplified homogeneous particle models are often used in remote sensing applications. In this study, the internal structure of individual atmospheric particles was imaged with the aim of parameterizing particle structural heterogeneity. To this end, ambient urban pollution, desert dust, and biomass burning particles were sampled in northern Europe and western Africa and analyzed by transmission electron microscopy coupled with energy dispersive X‐ray spectroscopy. Among 8,441 observed particles, about 60% of urban and 20% of desert dust particles presented residuals of coating compounds in the form of a halo surrounding a solid core. Graphic outlining of core and halo areas by image analysis revealed a dependence between halo and core dimensions as well as a greater ratio of halos thickness to total particle diameter (core plus halo) for smaller cores than for larger ones. In the case of urban pollution, the mean ratio for submicrometer and supermicrometer size fractions was 0.25 and 0.19, respectively. The corresponding mean values in the desert dust case were somewhat lower (0.22 and 0.14, respectively), but show a similar decreasing trend. Under the assumption that the halo dimension is proportional to the thickness of the particle shell, the obtained core versus shell dependencies were implemented in numerical calculations of aerosol optical characteristics. Different scenarios of the core‐shell dependencies were analyzed with respect to the influence on aerosol optical characteristics, bringing insights into sensitivity to parameterization of the core‐shell particle model in remote sensing algorithms.
X-ray-activated long persistent phosphors featuring strong UVC afterglow emissions
Authors: Yang Yan-Min , Li Zhi-Yong , Zhang Jun-Ying , Lu Yue , Guo Shao-Qiang , Zhao Qing , Wang Xin , Yong Zi-Jun , Li Hong , Ma Ju-Ping , Kuroiwa Yoshihiro , Moriyoshi Chikako , Hu Li-Li , Zhang Li-Yan , Zheng Li-Rong , Sun Hong-Tao 
Published: November 2018

AbstractPhosphors emitting visible and near-infrared persistent luminescence have been explored extensively owing to their unusual properties and commercial interest in their applications such as glow-in-the-dark paints, optical information storage, and in vivo bioimaging. However, no persistent phosphor that features emissions in the ultraviolet C range (200–280 nm) has been known to exist so far. Here, we demonstrate a strategy for creating a new generation of persistent phosphor that exhibits strong ultraviolet C emission with an initial power density over 10 milliwatts per square meter and an afterglow of more than 2 h. Experimental characterizations coupled with first-principles calculations have revealed that structural defects associated with oxygen introduction-induced anion vacancies in fluoride elpasolite can function as electron traps, which capture and store a large number of electrons triggered by X-ray irradiation. Notably, we show that the ultraviolet C afterglow intensity of the yielded phosphor is sufficiently strong for sterilization. Our discovery of this ultraviolet C afterglow opens up new avenues for research on persistent phosphors, and it offers new perspectives on their applications in terms of sterilization, disinfection, drug release, cancer treatment, anti-counterfeiting, and beyond.
Experience with bruxism in the everyday oral implantology practice in the Netherlands: a qualitative study
Authors: Thymi Magdalini , Rollman Annemiek , Visscher Corine M. , Wismeijer Daniel , Lobbezoo Frank 
Published: November 2018

Abstract
Objective
To explore how bruxism is dealt with by accredited oral implantologists within daily clinical practice.

Materials and methods
Nine semi-structured interviews of oral implantologists practicing in non-academic clinical practices in the Netherlands were performed, and thematic analysis was conducted using a framework-based approach.

Results
Oral implant treatments in bruxing patients were a generally well-accepted practice. Complications were often expected, with most being of minor impact. Contradictive attitudes emerged on the topic of bruxism being an etiologic factor for peri-implant bone loss and loss of osseointegration. Views on the ideal treatment plan varied, though the importance of the superstructure’s occlusion and articulation features was repeatedly pointed at. Similarly, views on protective splints varied, regarding their necessity and material choice. Bruxism was diagnosed mainly by clinical examination, alongside with patient anamnesis and clinician’s intuition. There was little attention for awake bruxism.

Discussion
Bruxism was generally not considered a contraindication for implantological treatments by accredited oral implantologists. Views on the interaction between bruxism and bone loss/loss of osseointegration varied, as did views on the ideal treatment plan.

Conclusions
There is a need for better understanding of the extent to which, and under which circumstances, sleep and/or awake bruxism can be seen as causal factors for the occurrence of oral implant complications.
Fungal spores as a source of sodium salt particles in the Amazon basin
Authors: China Swarup , Burrows Susannah M. , Wang Bingbing , Harder Tristan H. , Weis Johannes , Tanarhte Meryem , Rizzo Luciana V. , Brito Joel , Cirino Glauber G. , Ma Po-Lun , Cliff John , Artaxo Paulo , Gilles Mary K. , Laskin Alexander 
Published: November 2018

AbstractIn the Amazon basin, particles containing mixed sodium salts are routinely observed and are attributed to marine aerosols transported from the Atlantic Ocean. Using chemical imaging analysis, we show that, during the wet season, fungal spores emitted by the forest biosphere contribute at least 30% (by number) to sodium salt particles in the central Amazon basin. Hydration experiments indicate that sodium content in fungal spores governs their growth factors. Modeling results suggest that fungal spores account for ~69% (31–95%) of the total sodium mass during the wet season and that their fractional contribution increases during nighttime. Contrary to common assumptions that sodium-containing aerosols originate primarily from marine sources, our results suggest that locally-emitted fungal spores contribute substantially to the number and mass of coarse particles containing sodium. Hence, their role in cloud formation and contribution to salt cycles and the terrestrial ecosystem in the Amazon basin warrant further consideration.
Winding around non-Hermitian singularities
Authors: Zhong Qi , Khajavikhan Mercedeh , Christodoulides Demetrios N. , El-Ganainy Ramy 
Published: November 2018

AbstractNon-Hermitian singularities are ubiquitous in non-conservative open systems. Owing to their peculiar topology, they can remotely induce observable effects when encircled by closed trajectories in the parameter space. To date, a general formalism for describing this process beyond simple cases is still lacking. Here we develop a general approach for treating this problem by utilizing the power of permutation operators and representation theory. This in turn allows us to reveal a surprising result that has so far escaped attention: loops that enclose the same singularities in the parameter space starting from the same point and traveling in the same direction, do not necessarily share the same end outcome. Interestingly, we find that this equivalence can be formally established only by invoking the topological notion of homotopy. Our findings are general with far reaching implications in various fields ranging from photonics and atomic physics to microwaves and acoustics.
Atomic scale insights into structure instability and decomposition pathway of methylammonium lead iodide perovskite
Authors: Chen Shulin , Zhang Xiaowei , Zhao Jinjin , Zhang Ying , Kong Guoli , Li Qian , Li Ning , Yu Yue , Xu Ningan , Zhang Jingmin , Liu Kaihui , Zhao Qing , Cao Jian , Feng Jicai , Li Xinzheng , Qi Junlei , Yu Dapeng , Li Jiangyu , Gao Peng 
Published: November 2018

AbstractOrganic–inorganic hybrid perovskites are promising candidates for the next-generation solar cells. Many efforts have been made to study their structures in the search for a better mechanistic understanding to guide the materials optimization. Here, we investigate the structure instability of the single-crystalline CH3NH3PbI3 (MAPbI3) film by using transmission electron microscopy. We find that MAPbI3 is very sensitive to the electron beam illumination and rapidly decomposes into the hexagonal PbI2. We propose a decomposition pathway, initiated with the loss of iodine ions, resulting in eventual collapse of perovskite structure and its decomposition into PbI2. These findings impose important question on the interpretation of experimental data based on electron diffraction and highlight the need to circumvent material decomposition in future electron microscopy studies. The structural evolution during decomposition process also sheds light on the structure instability of organic–inorganic hybrid perovskites in solar cell applications.
Metastable silica high pressure polymorphs as structural proxies of deep Earth silicate melts
Authors: Bykova E. , Bykov M. , Černok A. , Tidholm J. , Simak S. I. , Hellman O. , Belov M. P. , Abrikosov I. A. , Liermann H.-P. , Hanfland M. , Prakapenka V. B. , Prescher C. , Dubrovinskaia N. , Dubrovinsky L. 
Published: November 2018

AbstractModelling of processes involving deep Earth liquids requires information on their structures and compression mechanisms. However, knowledge of the local structures of silicates and silica (SiO2) melts at deep mantle conditions and of their densification mechanisms is still limited. Here we report the synthesis and characterization of metastable high-pressure silica phases, coesite-IV and coesite-V, using in situ single-crystal X-ray diffraction and ab initio simulations. Their crystal structures are drastically different from any previously considered models, but explain well features of pair-distribution functions of highly densified silica glass and molten basalt at high pressure. Built of four, five-, and six-coordinated silicon, coesite-IV and coesite-V contain SiO6 octahedra, which, at odds with 3rd Pauling’s rule, are connected through common faces. Our results suggest that possible silicate liquids in Earth’s lower mantle may have complex structures making them more compressible than previously supposed.