bluuebunny/crossref_metadata_2025_split huggingface dataset:
Winter Weather Whiplash: Impacts of Meteorological Events Misaligned With Natural and Human Systems in Seasonally Snow‐Covered Regions
Authors: Casson N. J. , Contosta A. R. , Burakowski E. A. , Campbell J. L. , Crandall M. S. , Creed I. F. , Eimers M. C. , Garlick S. , Lutz D. A. , Morison M. Q. , Morzillo A. T. , Nelson S. J. 
Published: November 2019

Abstract“Weather whiplash” is a colloquial phrase for describing an extreme event that includes shifts between two opposing weather conditions. Prior media coverage and research on these types of extremes have largely ignored winter weather events. However, rapid swings in winter weather can result in crossing from frozen to unfrozen conditions, or vice versa; thus, the potential impact of these types of events on coupled human and natural systems may be large. Given rapidly changing winter conditions in seasonally snow‐covered regions, there is a pressing need for a deeper understanding of such events and the extent of their impacts to minimize their risks. Here we introduce the concept of winter weather whiplash, defined as a class of extreme event in which a collision of unexpected conditions produces a forceful, rapid, back‐and‐forth change in winter weather that induces an outsized impact on coupled human and natural systems. Using a series of case studies, we demonstrate that the effects of winter weather whiplash events depend on the natural and human context in which they occur, and discuss how these events may result in the restructuring of social and ecological systems. We use the long‐term hydrometeorological record at the Hubbard Brook Experimental Forest in New Hampshire, USA to demonstrate quantitative methods for delineating winter weather whiplash events and their biophysical impacts. Ultimately, we argue that robust conceptual and quantitative frameworks for understanding winter weather whiplash events will contribute to the ways in which we mitigate and adapt to winter climate change in vulnerable regions.
Submesoscale and Mesoscale Eddies in the Florida Straits: Observations from Satellite Ocean Color Measurements
Authors: Zhang Yingjun , Hu Chuanmin , Liu Yonggang , Weisberg Robert H. , Kourafalou Vassiliki H. 
Published: November 2019

AbstractDespite their well‐recognized importance in driving ocean physics and biology, submesoscale (diameter < Rossby radius of deformation) eddies have been extremely difficult to observe due to technical difficulties from both field and remote platforms. Here using novel satellite ocean color data products and modified algorithms, we address this challenge for the Florida Straits (22–28°N, 78–85°W). Between 2002 and 2018, while mesoscale eddies (radius >15 km) show strong seasonality with occurrence frequency decreasing from Lower Keys to Upper Keys, submesoscale eddies show little or no seasonality with high occurrence frequency restricted to 30–200‐m isobaths. The number of mesoscale eddies decreases exponentially in size, but submesoscale eddies show a normal distribution in size. These findings are significant in filling our knowledge gap in submesoscale eddies in this physically and ecologically important region as it encompasses world‐renowned coral reefs, seagrasses, and fisheries.
Realistic Quasi‐Biennial Oscillation Variability in Historical and Decadal Hindcast Simulations Using CMIP6 Forcing
Authors: Pohlmann Holger , Müller Wolfgang A. , Bittner Matthias , Hettrich Sebastian , Modali Kameswarrao , Pankatz Klaus , Marotzke Jochem 
Published: November 2019

AbstractWe analyze the quasi‐biennial oscillation (QBO) variability of historical and decadal hindcast simulations of the MiKlip (Mittelfristige Klimavorhersagen) decadal prediction system using the higher resolved version of the Max Planck Institute Earth System Model. We find a realistic variability of the QBO in historical simulations when changing from the Coupled Model Intercomparison Project Phase 5 (CMIP5) to the Coupled Model Intercomparison Project Phase 6 (CMIP6) external forcing. This agreement between the simulated and the observed QBO is improved by the initialization of decadal hindcast simulations with CMIP6 forcing in the first three lead years. In the decadal hindcast simulations, the agreement is similar to a persistence forecast in the first five lead years and higher than the persistence forecast in the later lead years. We find a strong relation between the QBO and the ozone variability in the stratosphere and conclude that the change of the ozone data from CMIP5 to CMIP6 leads to the improved QBO variability and prediction skill in our simulations.
N2(A) in the Terrestrial Thermosphere
Authors: Yonker Justin D. , Bailey Scott M. 
Published: November 2019

AbstractRecent work has indicated the presence of a nitric oxide (NO) product channel in the reaction between the higher vibrational levels of the first electronically excited state of molecular nitrogen, N2(A
), and atomic oxygen. A steady‐state model for the N2(A) vibrational distribution in the terrestrial thermosphere is here described and validated by comparison with N2 A‐X, Vegard‐Kaplan dayglow spectra from the Ionospheric Spectroscopy and Atmospheric Chemistry spectrograph. A computationally cheaper method is needed for implementation of the N2(A) chemistry into time‐dependent thermospheric models. It is shown that by scaling the photoelectron impact production of ionized N2 by a Gaussian centered near 100 km, the level‐specific N2(A) production rates between 100 and 200 km can be reproduced to within an average of 5%. This scaling, and thus the N2 electron impact ionization/excitation ratio, is nearly independent of existing uncertainties in the 2–20 nm solar soft X‐ray irradiance. To investigate this independence, the N2 electron‐impact excitation cross sections in the GLOW photoelectron model are replaced with the results of Johnson et al. (2005, https://doi.org/10.1029/2005JA011295) and the multipart work of Malone et al. (2009 https://doi.org/10.1103/PhysRevA.79.032704) (Malone, Johnson, Young, et al., 2009, https://doi.org/10.1088/0953-4075/42/22/225202; Malone, Johnson, Kanik, et al., 2009, https://doi.org/10.1103/PhysRevA.79.032705; Malone et al., 2009, https://doi.org/10.1103/PhysRevA.79.032704), together denoted J05M09. Upon updating these cross sections it is found that (1) the total N2 triplet excitation rate remains nearly constant; (2) the steady state N2(A) vibrational distribution is shifted to higher levels; (3) the total N2 singlet excitation rate responsible for the Lyman‐Birge‐Hopfield emission is reduced by 33%. It is argued that adopting the J05M09 cross sections supports (1) the larger X‐ray fluxes measured by the Student Nitric Oxide Explorer (SNOE) and (2) a temperature‐independent N2(A)+O reaction rate coefficient.
Estimation of the Occurrence Probability of Extreme Geomagnetic Storms by Applying Extreme Value Theory to Aa Index
Authors: Chen Si , Chai Lihui , Xu Kaihua , Wei Yong , Rong Zhaojin , Wan Weixing 
Published: November 2019

AbstractIn this work, the occurrence probability of extreme geomagnetic storms is estimated by applying extreme value theory to the geomagnetic activity Aa index. The Aa index has 172 years observation time span, which is much longer than other geomagnetic indices, and thus is more suitable for analysis for rarely occurred extreme geomagnetic storms. We use two newly developed extreme value theory methods, block maxima method and peak over threshold, and find that the extreme geomagnetic storm that happened in March 1989 may happen once per century. This result implies that we should pay more attention to such extreme geomagnetic storms that can cause space weather hazards.
Survey of Jupiter's Dawn Magnetosheath Using Juno
Authors: Ranquist D. A. , Bagenal F. , Wilson R. J. , Hospodarsky G. , Ebert R. W. , Allegrini F. , Valek P. , McComas D. J. , Connerney J. E. P. , Kurth W. S. , Bolton S. J. 
Published: November 2019

AbstractThe Juno spacecraft crossed Jupiter's bow shock and into the magnetosheath on 24 June 2016. It then went into 53‐day polar orbits with its apojoves at 113 Jovian radii on Jupiter's dawn side. These orbits have given us a unique opportunity to survey Jupiter's dawn magnetosheath. Using data from the Jovian Auroral Distributions Experiment, the Magnetic Field Investigation, and the Waves Investigation, we have identified 91 magnetosheath crossings for a total of 48.2 days of data. We present the statistical properties of the magnetosheath plasma, including density, velocity, magnetic field strength, temperature, plasma beta, pressures, and Mach numbers. We then show correlations between these various parameters. We confirm the rotation of the magnetic field to align with Jupiter's spin axis and find that this rotation correlates with several of the plasma properties, including magnetic field strength and plasma flow velocity. Finally, we discuss how these results can affect magnetic reconnection and the Kelvin‐Helmholtz instability at Jupiter's dawn magnetopause boundary.
The Permeability of Columnar Jointed Lava
Authors: Vasseur Jérémie , Wadsworth Fabian B. 
Published: November 2019

AbstractColumnar jointed lava is an important facies in many geothermal reservoir systems. The permeability of jointed lavas is dominated by the contribution from fracture networks. We use a scaling for the permeability of a set of fractures in a solid or porous mass and extend this to arrays of hexagonal intercolumn fractures. To validate our analytical results, we create numerical domains with relevant geometries and extract system‐scale permeability using the LBflow lattice‐Boltzmann fluid flow simulation tool. Finally, we model the cooling contraction of columns to extend our results so that they predict the permeability with time after lava emplacement. Importantly, we use these results to estimate the range of permeabilities typical of columnar joints that form during cooling from high temperature and are preserved in the crust at moderate to low temperatures.
Some Illustrations of Large Tectonically Driven Climate Changes in Earth History
Authors: Ramstein G. , Godderis Y. , Donnadieu Y. , Sepulchre P. , Fluteau F. , Zhang Z. , Zhang R. , Su B. , Jiang D. , Schuster M. , Besse J. 
Published: November 2019

AbstractA century ago, the pioneering book published in 1924 Die Klimate der geologischen Vorzeit explained by plate motion the evolution of vegetation revealed in sedimentary records. Nevertheless, they did not invoke climate changes. In the second part of the 20th century, the intricate relationship between tectonics, long‐term carbon cycle, and climate was depicted by Walker (1981). Since these major steps, climate modeling of the Earth system kept on improving and including more and more components and processes to enable the investigation of deep time periods using general circulation model that can account for atmosphere and ocean dynamics. Here we illustrate long but drastic climate changes clearly related with tectonics, through three different examples: (1) the crucial role of paleogeography (continental distribution) to explain the drawdown of atmospheric carbon dioxide and the huge glaciation associated that occurred during the Neoproterozoic period; (2) the shrinkage of large epicontinental Paratethys that covered a large part of Eastern Europe and Western Asia and its impact on both monsoonal systems (African and Asian) since 40 Ma; and (3) the large impact of mountain range uplifts since Eocene both in Asia (Tibetan Plateau and Himalaya) and in Africa (buildup of the rift), on atmosphere and ocean dynamics. These studies not only allow for testing the ability of Earth system models to capture long‐term changes of Earth climate, but they also pinpoint the pivotal role tectonics played in shaping the long‐term evolution of atmospheric CO2 and monsoon patterns.
Spatial Characteristics Reveal the Reactive Transport of Radium Isotopes (224Ra, 223Ra, and 228Ra) in an Intertidal Aquifer
Authors: Liu Yi , Jiao Jiu Jimmy , Mao Rong , Luo Xin , Liang Wenzhao , Robinson Clare E. 
Published: November 2019

AbstractThis study presents high‐resolution two‐dimensional distributions of radium isotopes in the shallow intertidal aquifer of Tolo Harbor, Hong Kong, illustrating the importance of salinity, groundwater residence time, and tidal flushing and mixing in controlling radium behavior in the system. The activities of radium isotopes are low in the fresh groundwater zone with activities increasing in the transition zone (1 < salinity < 25) due to desorption of radium from sediment surface coatings. In the high salinity zone (salinity > 25), the activities of radium isotopes increase with depth due to tidal flushing and mixing of the recirculating seawater in the shallow aquifer as well as increasing residence time with depth. The dissolved radium isotopes are identified to be in disequilibrium in shallow intertidal aquifer based on radium isotopic ratios and observed depletion of dissolved radium isotopes compared to the theoretical mixing line between the equilibrium activity and fresh groundwater. The influence of continuous tidal flushing of the shallow intertidal aquifer on radium is revealed, and shallow sediments are observed to have less total exchangeable radium isotopes than deeper in the aquifer. A new one‐dimensional reactive transport model that considers a depth‐dependent production rate is applied to simulate the vertical distribution of radium isotopes in the intertidal aquifer as seawater infiltrates the beach. Using least squares fitting of the model to field data, the vertical infiltration seepage velocity is estimated to be ~0.5 m/day, and the dimensionless adsorption partition coefficient of radium isotopes (K) is 350. This agrees well with K values (202–365) calculated using an adsorption/desorption model as well as measured values (266 in February and 205 in April). Based on the spatial distribution of radium isotopes and flow patterns in the intertidal aquifer, groundwater in Ra disequilibrium zone is recommended as the endmember for tide‐ or wave‐driven submarine groundwater discharge (SGD) that has shallow flow paths, and groundwater in Ra equilibrium zone is recommended as endmember for seasonally driven or density‐driven SGD that has deep flow paths.
Silencing of long noncoding RNA HOXA11-AS inhibits the Wnt signaling pathway via the upregulation of HOXA11 and thereby inhibits the proliferation, invasion, and self-renewal of hepatocellular carcinoma stem cells
Authors: Guo Jun-Cheng , Yang Yi-Jun , Zheng Jin-Fang , Zhang Jian-Quan , Guo Min , Yang Xiang , Jiang Xiang-Ling , Xiang Li , Li You , Ping Huang , Zhuo Liu 
Published: November 2019

AbstractHepatocellular carcinoma (HCC) is a major cause of cancer-related deaths, but its molecular mechanisms are not yet well characterized. Long noncoding RNAs (lncRNAs) play crucial roles in tumorigenesis, including that of HCC. However, the role of homeobox A11 antisense (HOXA11-AS) in determining HCC stem cell characteristics remains to be explained; hence, this study aimed to investigate the effects of HOXA11-AS on HCC stem cell characteristics. Initially, the expression patterns of HOXA11-AS and HOXA11 in HCC tissues, cells, and stem cells were determined. HCC stem cells, successfully sorted from Hep3B and Huh7 cells, were transfected with short hairpin or overexpression plasmids for HOXA11-AS or HOXA11 overexpression and depletion, with an aim to study the influences of these mediators on the self-renewal, proliferation, migration, and tumorigenicity of HCC stem cells in vivo. Additionally, the potential relationship and the regulatory mechanisms that link HOXA11-AS, HOXA11, and the Wnt signaling pathway were explored through treatment with Dickkopf-1 (a Wnt signaling pathway inhibitor). HCC stem cells showed high expression of HOXA11-AS and low expression of HOXA11. Both HOXA11-AS silencing and HOXA11 overexpression suppressed the self-renewal, proliferation, migration, and tumorigenicity of HCC stem cells in vivo, as evidenced by the decreased expression of cancer stem cell surface markers (CD133 and CD44) and stemness-related transcription factors (Nanog, Sox2, and Oct4). Moreover, silencing HOXA11-AS inactivated the Wnt signaling pathway by decreasing the methylation level of the HOXA11 promoter, thereby inhibiting HCC stem cell characteristics. Collectively, this study suggested that HOXA11-AS silencing exerts an antitumor effect, suppressing HCC development via Wnt signaling pathway inactivation by decreasing the methylation level of the HOXA11 promoter.
Extracting more light for vertical emission: high power continuous wave operation of 1.3-μm quantum-dot photonic-crystal surface-emitting laser based on a flat band
Authors: Lu Huan-Yu , Tian Si-Cong , Tong Cun-Zhu , Wang Li-Jie , Rong Jia-Min , Liu Chong-Yang , Wang Hong , Shu Shi-Li , Wang Li-Jun 
Published: November 2019

AbstractFor long distance optical interconnects, 1.3-μm surface-emitting lasers are key devices. However, the low output power of several milliwatts limits their application. In this study, by introducing a two-dimensional photonic-crystal and using InAs quantum dots as active materials, a continuous-wave, 13.3-mW output power, 1.3-μm wavelength, room-temperature surface-emitting laser is achieved. In addition, such a device can be operated at high temperatures of up to 90 °C. The enhanced output power results from the flat band structure of the photonic crystal and an extra feedback mechanism. Surface emission is realized by photonic crystal diffraction and thus the distributed Bragg reflector is eliminated. The proposed device provides a means to overcome the limitations of low-power 1.3-μm surface-emitting lasers and increase the number of applications thereof.
Dual phases of crystalline and electronic structures in the nanocrystalline perovskite CsPbBr3
Authors: Whitcher T. J. , Gomes L. C. , Zhao D. , Bosman M. , Chi X. , Wang Y. , Carvalho A. , Hui H. K. , Chang Q. , Breese M. B. H. , Castro Neto A. H. , Wee A. T. S. , Sun H. D. , Chia E. E. M. , Rusydi A. 
Published: November 2019

AbstractInorganic perovskites have recently attracted much attention as promising new nanocrystalline materials that have interesting fundamental phenomena and great potential in several applications. Herein, we reveal unusual structural and electronic changes in nanocrystalline cesium lead bromide (CsPbBr3) as a function of temperature using high-resolution spectroscopic ellipsometry, high-resolution transmission electron microscopy and terahertz spectroscopy measurements supported by first-principles calculations. New dual phases of crystalline and electronic structures are observed due to the nanocrystalline nature of the material. Interestingly, a change in the electronic structure occurs below 150 K, and the rate at which the nanocrystal transitions from the tetragonal to orthorhombic phase is found to be nonlinear with temperature. Our results show the importance of the charge and lattice interplay in determining the dual phases and fundamental properties of nanocrystalline materials.
Interplay between α2-chimaerin and Rac1 activity determines dynamic maintenance of long-term memory
Authors: Lv Li , Liu Yunlong , Xie Jianxin , Wu Yan , Zhao Jianjian , Li Qian , Zhong Yi 
Published: November 2019

AbstractMemory consolidation theory suggests that once memory formation has been completed, memory is maintained at a stable strength and is incapable of further enhancement. However, the current study reveals that even long after formation, contextual fear memory could be further enhanced. Such unexpected enhancement is possible because memory is dynamically maintained at an intermediate level that allows for bidirectional regulation. Here we find that both Rac1 activation and expression of α2-chimaerin are stimulated by single-trial contextual fear conditioning. Such sustained Rac1 activity mediates reversible forgetting, and α2-chimaerin acts as a memory molecule that reverses forgetting to sustain memory through inhibition of Rac1 activity during the maintenance stage. Therefore, the balance between activated Rac1 and expressed α2-chimaerin defines dynamic long-term memory maintenance. Our findings demonstrate that consolidated memory maintains capacity for bidirectional regulation.
Spatial control over catalyst positioning on biodegradable polymeric nanomotors
Authors: Toebes B. Jelle , Cao F. , Wilson Daniela A. 
Published: November 2019

AbstractScientists over the world are inspired by biological nanomotors and try to mimic these complex structures. In recent years multiple nanomotors have been created for various fields, such as biomedical applications or environmental remediation, which require a different design both in terms of size and shape, as well as material properties. So far, only relatively simple designs for synthetic nanomotors have been reported. Herein, we report an approach to create biodegradable polymeric nanomotors with a multivalent design. PEG-PDLLA (poly(ethylene glycol)-b-poly(D,L-lactide)) stomatocytes with azide handles were created that were selectively reduced on the outside surface by TCEP (tris(2-carboxyethyl)phosphine) functionalized beads. Thereby, two different functional handles were created, both on the inner and outer surface of the stomatocytes, providing spatial control for catalyst positioning. Enzymes were coupled on the inside of the stomatocyte to induce motion in the presence of fuel, while fluorophores and other molecules can be attached on the outside.
Thermally activated delayed fluorescence with 7% external quantum efficiency from a light-emitting electrochemical cell
Authors: Lundberg Petter , Tsuchiya Youichi , Lindh E. Mattias , Tang Shi , Adachi Chihaya , Edman Ludvig 
Published: November 2019

AbstractWe report on light-emitting electrochemical cells, comprising a solution-processed single-layer active material and air-stabile electrodes, that exhibit efficient and bright thermally activated delayed fluorescence. Our optimized devices delivers a luminance of 120 cd m−2 at an external quantum efficiency of 7.0%. As such, it outperforms the combined luminance/efficiency state-of-the art for thermally activated delayed fluorescence light-emitting electrochemical cells by one order of magnitude. For this end, we employed a polymeric blend host for balanced electrochemical doping and electronic transport as well as uniform film formation, an optimized concentration (<1 mass%) of guest for complete host-to-guest energy transfer at minimized aggregation and efficient emission, and an appropriate concentration of an electrochemically stabile electrolyte for desired doping effects. The generic nature of our approach is manifested in the attainment of bright and efficient thermally activated delayed fluorescence emission from three different light-emitting electrochemical cells with invariant host:guest:electrolyte number ratio.
Glycerol-3-phosphate mediates rhizobia-induced systemic signaling in soybean
Authors: Shine M. B. , Gao Qing-ming , Chowda-Reddy R. V. , Singh Asheesh K. , Kachroo Pradeep , Kachroo Aardra 
Published: November 2019

AbstractGlycerol-3-phosphate (G3P) is a well-known mobile regulator of systemic acquired resistance (SAR), which provides broad spectrum systemic immunity in response to localized foliar pathogenic infections. We show that G3P-derived foliar immunity is also activated in response to genetically-regulated incompatible interactions with nitrogen-fixing bacteria. Using gene knock-down we show that G3P is essential for strain-specific exclusion of non-desirable root-nodulating bacteria and the associated foliar pathogen immunity in soybean. Grafting studies show that while recognition of rhizobium incompatibility is root driven, bacterial exclusion requires G3P biosynthesis in the shoot. Biochemical analyses support shoot-to-root transport of G3P during incompatible rhizobia interaction. We describe a root-shoot-root signaling mechanism which simultaneously enables the plant to exclude non-desirable nitrogen-fixing rhizobia in the root and pathogenic microbes in the shoot.