bluuebunny/crossref_metadata_2025_split huggingface dataset:
September 2017 Solar Flare Event: Rapid Heating of the Martian Neutral Upper Atmosphere From the X‐Class Flare as Observed by MAVEN
Authors: Elrod M. K. , Curry S. M. , Thiemann E. M. B. , Jain S. K. 
Published: July 2018

AbstractOn 10 September 2017, the Mars Atmosphere and Volatile EvolutioN mission observed a particularly strong X‐class flare. This paper will focus on observations made by Neutral Gas and Ion Mass Spectrometer (NGIMS) and the flare response detected by extreme ultraviolet monitor. We focus the data to the region of the upper atmosphere from 160 to 300 km and to 10 orbits before and after the flare. The flare peaked near 16:12 UTC with the closest periapsis pass from 17:30 to 17:54 UTC (Lee et al., , https://doi.org/10.1029/2018GL079162). NGIMS measured a significant enhancement in the neutral densities above 195 km for the flare. This enhancement stands out for the major species measured by NGIMS (Ar, CO2, CO, O, and N2). The correlation of the flare and the enhancement in density and temperature in the upper atmosphere indicates that solar flare heating is most likely the main driver and has important implications for the effects of space weather events on terrestrial atmospheres.
Self‐Amplifying Feedbacks Accelerate Greening and Warming of the Arctic
Authors: Zhang W. , Miller P. A. , Jansson C. , Samuelsson P. , Mao J. , Smith B. 
Published: July 2018

AbstractIncreased greening, higher vegetation productivity, and shrubification have been observed in Arctic tundra in response to recent warming. Such changes have affected the near‐surface climate through opposing biogeophysical feedbacks (BF) associated with changes to albedo and evapotranspiration. However, the likely spatiotemporal variations of BF to future climate change and the consequences for Arctic vegetation and ecology have not been robustly quantified. We apply a regional Earth system model (RCA‐GUESS) interactively coupling atmospheric dynamics to land vegetation response in three potential 21st‐century radiative forcing simulations for the Arctic. We find that BF, dominated by albedo‐mediated warming in early spring and evapotranspiration‐mediated cooling in summer, have the potential to amplify or modulate local warming and enhance summer precipitation over land. The magnitude of these effects depends on radiative forcing and subsequent ecosystem responses. Thus, it is important to account for BF when assessing future Arctic climate change and its ecosystem impacts.
Can Ningaloo Niño/Niña Develop Without El Niño–Southern Oscillation?
Authors: Kataoka Takahito , Masson Sébastien , Izumo Takeshi , Tozuka Tomoki , Yamagata Toshio 
Published: July 2018

AbstractNingaloo Niño/Niña is the dominant climate mode in the southeastern Indian Ocean with its center of positive/negative sea surface temperature anomalies attached to Australia. Ningaloo Niño is the major cause of marine heatwaves in the region. Although oceanic variability in this region has long been considered mainly as a response to the El Niño–Southern Oscillation (ENSO), some recent studies have suggested the possible existence of local air‐sea feedback processes. Using a state‐of‐the‐art ocean‐atmosphere coupled model that realistically simulates Ningaloo Niño/Niña, whether Ningaloo Niño/Niña can occur independently of ENSO is examined. Even in an experiment in which ENSO is suppressed by strongly nudging tropical Pacific sea surface temperatures toward the model climatology, Ningaloo Niño/Niña with a similar magnitude and seasonality still develops, likely through an air‐sea interaction off Western Australia amplifying atmospheric stochastic forcing. This study is the first to show that Ningaloo Niño/Niña can develop even without ENSO.
Observations and Modeling of the Mars Low‐Altitude Ionospheric Response to the 10 September 2017 X‐Class Solar Flare
Authors: Xu Shaosui , Thiemann Ed , Mitchell David , Eparvier Frank , Pawlowski David , Benna Mehdi , Andersson Laila , Liemohn Michael W. , Bougher Stephen , Mazelle Christian 
Published: July 2018

AbstractSolar extreme ultraviolet and X‐ray photons are the main sources of ionization in the Martian ionosphere and can be enhanced significantly during a solar flare. On 10 September 2017, the Mars Atmosphere and Volatile EvolutioN orbiter observed an X8.2 solar flare, the largest it has encountered to date. Here we investigate the ionospheric response before, during, and after this event with the SuperThermal Electron Transport model. We find good agreement between modeled and measured photoelectron spectra. In addition, the high photoelectron fluxes during the flare provide adequate statistics to allow us to clearly and repeatedly identify the carbon Auger peak in the ionospheric photoelectron energy spectra at Mars for the first time. By applying photochemical equilibrium, O
and CO
densities are obtained and compared with Mars Atmosphere and Volatile EvolutioN observations. The variations in ion densities during this event due to the solar irradiance enhancement and the neutral atmosphere expansion are discussed.
Understanding the Driver of Energetic Electron Precipitation Using Coordinated Multisatellite Measurements
Authors: Capannolo L. , Li W. , Ma Q. , Zhang X.‐J. , Redmon R. J. , Rodriguez J. V. , Kletzing C. A. , Kurth W. S. , Hospodarsky G. B. , Engebretson M. J. , Spence H. E. , Reeves G. D. 
Published: July 2018

AbstractMagnetospheric plasma waves play a significant role in ring current and radiation belt dynamics, leading to pitch angle scattering loss and/or stochastic acceleration of the particles. During a non‐storm time dropout event on 24 September 2013, intense electromagnetic ion cyclotron (EMIC) waves were detected by Van Allen Probe A (Radiation Belt Storm Probes‐A). We quantitatively analyze a conjunction event when Van Allen Probe A was located approximately along the same magnetic field line as MetOp‐01, which detected simultaneous precipitation of >30 keV protons and energetic electrons over an unexpectedly broad energy range (>~30 keV). Multipoint observations together with quasi‐linear theory provide direct evidence that the observed electron precipitation at higher energy (>~700 keV) is primarily driven by EMIC waves. However, the newly observed feature of the simultaneous electron precipitation extending down to ~30 keV is not supported by existing theories and raises an interesting question on whether EMIC waves can scatter such low‐energy electrons.
Mild and Arid Climate in the Eastern Sahara‐Arabian Desert During the Late Little Ice Age
Authors: Felis Thomas , Ionita Monica , Rimbu Norel , Lohmann Gerrit , Kölling Martin 
Published: July 2018

AbstractThe climate of the Sahara and Arabian Deserts during the Little Ice Age is not well known, due to a lack of annually resolved natural and documentary archives. We present an annual reconstruction of temperature and aridity derived from Sr/Ca and oxygen isotopes in a coral of the desert‐surrounded northern Red Sea. Our data indicate that the eastern Sahara and Arabian Deserts did not experience pronounced cooling during the late Little Ice Age (~1750–1850) but suggest an even more arid mean climate than in the following ~150 years. The mild temperatures are broadly in line with predominantly negative phases of the North Atlantic Oscillation during the Little Ice Age. The more arid climate is best explained by meridional advection of dry continental air from Eurasia. We find evidence for an abrupt termination of the more arid climate after 1850, coincident with a reorganization of the atmospheric circulation over Europe.
Cyclicity and Persistence of Earth's Evolution Over Time: Wavelet and Fractal Analysis
Authors: Chen Guoxiong , Cheng Qiuming 
Published: July 2018

AbstractAccessing the cyclicity and persistence of geological records with time series analysis deepens our understanding of Earth's long‐term evolution. In this study, time series from recent global zircon U‐Pb age and δ18O databases are analyzed using wavelet transform from a fractal perspective. Continuous wavelet transform of the local fractal sequences of both zircon records indicates a strong, persistent ~760 million year cycle over the 4.4 billion years of Earth's history. Wavelet coherence analysis shows that the U‐Pb age and δ18O systems are coupled in significant in‐phase coherence for a cycle of ~760 million year, implying synchronization between the two underlying processes. This study also demonstrates that the variation in the time series records manifests as 1/f β scaling behavior that persists β ~ 1.8 over the entire interval. This 1/f fractal scaling nature furnishes evidence for the conjecture that rather than being an equilibrium system, Earth's long‐term evolution follows a self‐organized pattern.
Coral Skeletons Record Increasing Agriculture‐Related Groundwater Nitrogen Inputs to a South Pacific Reef Over the Past Century
Authors: Erler Dirk V. , Shepherd Benjamin O. , Linsley Braddock K. , Lough Janice M. , Cantin Neal E. 
Published: July 2018

AbstractAnthropogenic activity on tropical islands has been linked with nitrogen (N) contamination of groundwater and subsequent coral reef health decline. However, identifying the temporal patterns of groundwater N contamination has proven difficult because of an absence of long‐term records. Here we use δ15N in coral skeleton organic material (CS‐δ15N) to reconstruct historical patterns of groundwater N discharge to a coral reef system at Rarotonga in the Cook Islands in the South Pacific. Analysis of coral skeletal material dating back to 1880 CE clearly shows that the δ15N of N available in the reef environment around Rarotonga increased between 1980 and 2000. We propose that rapid agricultural development in the Cook Islands between 1960 and 1985 increased aquifer N concentrations leading to the elevated δ15N of groundwater NO3−. The discharge of this groundwater N appears to have continued for at least 15 years after the cessation of the agricultural boom. This has important implications for the management of groundwater contamination on low‐lying tropical islands.
Do CMIP5 Models Reproduce Observed Low‐Frequency North Atlantic Jet Variability?
Authors: Bracegirdle Thomas J. , Lu Hua , Eade Rosie , Woollings Tim 
Published: July 2018

AbstractThe magnitude of observed multidecadal variations in the North Atlantic Oscillation (NAO) in winter is at the upper end of the range simulated by climate models and a clear explanation for this remains elusive. Recent research shows that observed multidecadal winter NAO variability is more strongly associated with North Atlantic (NA) jet strength than latitude, thus motivating a comprehensive comparison of NA jet and NAO variability across the Coupled Model Intercomparison Project Phase 5 (CMIP5) models. Our results show that the observed peak in multidecadal jet strength variability is even more unusual than NAO variability when compared to the model‐simulated range across 133 historical CMIP5 simulations. Some CMIP5 models appear capable of reproducing the observed low‐frequency peak in jet strength, but there are too few simulations of each model to clearly identify which. It is also found that an observed strong multidecadal correlation between jet strength and NAO since the mid‐nineteenth century may be specific to this period.
Thank You to Our 2017 Peer Reviewers
Authors: Geissman John , Jolivet Laurent , Niemi Nathan , Schildgen Taylor 
Published: July 2018

AbstractAn essential, respected, and critical aspect of the modern practice of science and scientific publishing is peer review. The process of peer review facilitates best practices in scientific conduct and communication, ensuring that manuscripts published as accurate, valuable, and clearly communicated. The over 152 papers published in Tectonics in 2017 benefit from the time, effort, and expertise of our reviewers who have provided thoughtfully considered advice on each manuscript. This role is critical to advancing our understanding of the evolution of the continents and their margins, as these reviews lead to even clearer and higher‐quality papers. In 2017, the over 423 papers submitted to Tectonics were the beneficiaries of more than 786 reviews provided by 562 members of the tectonics community and related disciplines. To everyone who has volunteered their time and intellect to peer reviewing, thank you for helping Tectonics and all other AGU Publications provide the best science possible.
Analysis of PARP inhibitor toxicity by multidimensional fluorescence microscopy reveals mechanisms of sensitivity and resistance
Authors: Michelena Jone , Lezaja Aleksandra , Teloni Federico , Schmid Thomas , Imhof Ralph , Altmeyer Matthias 
Published: July 2018

AbstractExploiting the full potential of anti-cancer drugs necessitates a detailed understanding of their cytotoxic effects. While standard omics approaches are limited to cell population averages, emerging single cell techniques currently lack throughput and are not applicable for compound screens. Here, we employed a versatile and sensitive high-content microscopy-based approach to overcome these limitations and quantify multiple parameters of cytotoxicity at the single cell level and in a cell cycle resolved manner. Applied to PARP inhibitors (PARPi) this approach revealed an S-phase-specific DNA damage response after only 15 min, quantitatively differentiated responses to several clinically important PARPi, allowed for cell cycle resolved analyses of PARP trapping, and predicted conditions of PARPi hypersensitivity and resistance. The approach illuminates cellular mechanisms of drug synergism and, through a targeted multivariate screen, could identify a functional interaction between PARPi olaparib and NEDD8/SCF inhibition, which we show is dependent on PARP1 and linked to PARP1 trapping.
A quantitative criterion for determining the order of magnetic phase transitions using the magnetocaloric effect
Authors: Law Jia Yan , Franco Victorino , Moreno-Ramírez Luis Miguel , Conde Alejandro , Karpenkov Dmitriy Y. , Radulov Iliya , Skokov Konstantin P. , Gutfleisch Oliver 
Published: July 2018

AbstractThe ideal magnetocaloric material would lay at the borderline of a first-order and a second-order phase transition. Hence, it is crucial to unambiguously determine the order of phase transitions for both applied magnetocaloric research as well as the characterization of other phase change materials. Although Ehrenfest provided a conceptually simple definition of the order of a phase transition, the known techniques for its determination based on magnetic measurements either provide erroneous results for specific cases or require extensive data analysis that depends on subjective appreciations of qualitative features of the data. Here we report a quantitative fingerprint of first-order thermomagnetic phase transitions: the exponent n from field dependence of magnetic entropy change presents a maximum of n > 2 only for first-order thermomagnetic phase transitions. This model-independent parameter allows evaluating the order of phase transition without any subjective interpretations, as we show for different types of materials and for the Bean–Rodbell model.
Direct electric field control of the skyrmion phase in a magnetoelectric insulator
Authors: Kruchkov A. J. , White J. S. , Bartkowiak M. , Živković I. , Magrez A. , Rønnow H. M. 
Published: July 2018

AbstractMagnetic skyrmions are topologically protected spin-whirls currently considered as promising for use in ultra-dense memory devices. Towards achieving this goal, exploration of the skyrmion phase response and under external stimuli is urgently required. Here we show experimentally, and explain theoretically, that in the magnetoelectric insulator Cu2OSeO3 the skyrmion phase can expand and shrink significantly depending on the polarity of a moderate applied electric field (few V/μm). The theory we develop incorporates fluctuations around the mean-field that clarifies precisely how the electric field provides direct control over the free energy difference between the skyrmion and the surrounding conical phase. The quantitative agreement between theory and experiment provides a solid foundation for the development of skyrmionic applications based on magnetoelectric coupling.
Targeting CD44v6 for fluorescence-guided surgery in head and neck squamous cell carcinoma
Authors: Odenthal Julia , Rijpkema Mark , Bos Desirée , Wagena Esther , Croes Huib , Grenman Reidar , Boerman Otto , Takes Robert , Friedl Peter 
Published: July 2018

AbstractHead and neck squamous cell carcinoma (HNSCC) is an often highly invasive tumor, infiltrating functionally important tissue areas. Achieving complete tumor resection and preserving functionally relevant tissue structures depends on precise identification of tumor-free resection margins during surgery. Fluorescence-guided surgery (FGS), by intraoperative detection of tumor cells using a fluorescent tracer, may guide surgical excision and identify tumor-positive resection margins. Using a literature survey on potential surface molecules followed by immunohistochemical validation, we identified CD44 variant 6 (CD44v6) as a constitutively expressed antigen in the invasion zone of HNSCC lesions. The monoclonal anti-CD44v6 antibody BIWA was labeled with both a near-infrared fluorescent dye (IRDye800CW) and a radioactive label (Indium-111) and dual-modality imaging was applied in a locally invasive tumor mouse model. BIWA accurately detected human HNSCC xenografts in mice with a tumor uptake of 54 ± 11% ID/g and invasion regions with an accuracy of 94%. When dissected under clinical-like conditions, tumor remnants approximately 0.7 mm in diameter consisting of a few thousand cells were identified by fluorescence imaging, resulting in reliable dissection of invasive microregions. These data indicate that CD44v6 is a suitable target for reliable near-infrared detection and FGS of invasive HNSCC lesions in vivo.
Nitazoxanide inhibits paramyxovirus replication by targeting the Fusion protein folding: role of glycoprotein-specific thiol oxidoreductase ERp57
Authors: Piacentini Sara , La Frazia Simone , Riccio Anna , Pedersen Jens Z. , Topai Alessandra , Nicolotti Orazio , Rossignol Jean-Francois , Santoro M. Gabriella 
Published: July 2018

AbstractParamyxoviridae, a large family of enveloped viruses harboring a nonsegmented negative-sense RNA genome, include important human pathogens as measles, mumps, respiratory syncytial virus (RSV), parainfluenza viruses, and henipaviruses, which cause some of the deadliest emerging zoonoses. There is no effective antiviral chemotherapy for most of these pathogens. Paramyxoviruses evolved a sophisticated membrane-fusion machine consisting of receptor-binding proteins and the fusion F-protein, critical for virus infectivity. Herein we identify the antiprotozoal/antimicrobial nitazoxanide as a potential anti-paramyxovirus drug targeting the F-protein. We show that nitazoxanide and its circulating-metabolite tizoxanide act at post-entry level by provoking Sendai virus and RSV F-protein aggregate formation, halting F-trafficking to the host plasma membrane. F-protein folding depends on ER-resident glycoprotein-specific thiol-oxidoreductase ERp57 for correct disulfide-bond architecture. We found that tizoxanide behaves as an ERp57 non-competitive inhibitor; the putative drug binding-site was located at the ERp57-b/b′ non-catalytic domains interface. ERp57-silencing mimicked thiazolide-induced F-protein alterations, suggesting an important role of this foldase in thiazolides anti-paramyxovirus activity. Nitazoxanide is used in the clinic as a safe and effective antiprotozoal/antimicrobial drug; its antiviral activity was shown in patients infected with hepatitis-C virus, rotavirus and influenza viruses. Our results now suggest that nitazoxanide may be effective also against paramyxovirus infection.
Ultrahigh-temperature tensile creep of TiC-reinforced Mo-Si-B-based alloy
Authors: Kamata Shiho Yamamoto , Kanekon Daiki , Lu Yuanyuan , Sekido Nobuaki , Maruyama Kouichi , Eggeler Gunther , Yoshimi Kyosuke 
Published: July 2018

AbstractIn this study, the ultrahigh-temperature tensile creep behaviour of a TiC-reinforced Mo-Si-B-based alloy was investigated in the temperature range of 1400–1600 °C at constant true stress. The tests were performed in a stress range of 100–300 MPa for 400 h under vacuum, and creep rupture data were rationalized with Larson-Miller and Monkman-Grant plots. Interestingly, the MoSiBTiC alloy displayed excellent creep strength with relatively reasonable creep parameters in the ultrahigh-temperature range: a rupture time of ~400 h at 1400 °C under 137 MPa with a stress exponent (n) of 3 and an apparent activation energy of creep (Qapp) of 550 kJ/mol. The increasing rupture strains with decreasing stresses (up to 70%) and moderate strain-rate oscillations in the creep curves suggest that two mechanisms contribute to the creep: phase boundary sliding between the hard T2 and (Ti,Mo)C phases and the Moss phase, and dynamic recovery and recrystallization in Moss, observed with orientation imaging scanning electron microscopy. The results presented here represent the first full analysis of creep for the MoSiBTiC alloy in an ultrahigh-temperature range. They indicate that the high-temperature mechanical properties of this material under vacuum are promising.
Thiamine tetrahydrofurfuryl disulfide promotes voluntary activity through dopaminergic activation in the medial prefrontal cortex
Authors: Saiki Masato , Matsui Takashi , Soya Mariko , Kashibe Tomomi , Shima Takeru , Shimizu Takeshi , Naruto Takehiro , Kitayoshi Takahito , Akimoto Kouji , Ninomiya Shinji , Soya Hideaki 
Published: July 2018

AbstractA physically active lifestyle is associated with better health in body and mind, and it is urgent that supporting agents for such lifestyles be developed. In rodents, voluntary locomotor activity as an active physical behavior may be mediated by dopaminergic neurons (DNs). Thiamine phosphate esters can stimulate DNs, and we thus hypothesized that thiamine tetrahydrofurfuryl disulfide (TTFD), a thiamine derivative, promotes locomotor activity via DNs in rats. Acute i.p. administration of TTFD enhanced rat locomotor activity in a normal cage. In vivo microdialysis revealed that TTFD-enhanced locomotor activity was synchronized with dopamine release in the medial prefrontal cortex (mPFC). Antagonism of the dopamine D1 receptor, but not D2 receptor, in the mPFC fully suppressed TTFD-enhanced locomotor activity. Finally, we found a TTFD dose-dependent increase in voluntary wheel running. Our findings demonstrate that DNs in the mPFC mediates TTFD-enhanced locomotor activity, suggesting the potential of TTFD to induce active physical behavior.
Nucleation Mechanisms of CO2 Hydrate Reflected by Gas Solubility
Authors: Zhang Peng , Wu Qingbai , Mu Cuicui , Chen Xueping 
Published: July 2018

AbstractThe concentration of gas has been confirmed as a key factor dominating hydrate nucleation. In this study, CO2 hydrates were formed in pure water and a sodium dodecyl sulphate (SDS) solution using a temperature reduction method under constant pressure at different temperatures. The dissolving properties of CO2 throughout the whole induction period were investigated in detail. The experimental results showed that the ‘memory effect’ of hydrate might not be attributed to residual water structures after hydrate dissociation. Instead, residual gas molecules in the aqueous phase should receive more attention. Hydrate nucleation was confirmed to be a type of chain reaction. Low temperature was a significant factor that promoted hydrate nucleation. As a result, these two factors enhanced the stochastic features of the CO2 hydrate nucleation reaction. Even under the same conditions, critical gas concentrations beyond the threshold that hydrates can spontaneously nucleate were not fixed, but they still exhibited linear relations regarding a set temperature. Taking the significant influences of temperature into account, a new nucleation mechanism for CO2 hydrates was established based on the potential of the reaction system. Therefore, this study sheds new light when explaining the reason for the formation of gas hydrates in natural reservoirs.