bluuebunny/crossref_metadata_2025_split huggingface dataset:
Probing the Sources of Uncertainty in Transient Warming on Different Timescales
Authors: Lutsko Nicholas J. , Popp Max 
Published: September 2019

AbstractThe rate of transient warming is determined by a number of factors, notably the radiative forcing from increasing CO2 concentrations and the net radiative feedback. Uncertainty in transient warming comes from both the uncertainty in each factor and from the warming's sensitivity to uncertainty in each factor. An energy balance model is used to untangle these two components of uncertainty in transient warming, which is shown to be most sensitive to uncertainty in the forcing and not to uncertainty in radiative feedbacks. Additionally, uncertainty in the efficacy of ocean heat uptake is more important than uncertainty in the rate of ocean heat uptake. Three further implications are as follows: (1) transient warming is highly sensitive to uncertainty in emissions, (2) caution is warranted when extrapolating future warming trends from short‐lived climate perturbations, and (3) climate models tuned using the historical record are highly sensitive to assumptions made about the historical forcing.
Indian Ocean Warming Trend Reduces Pacific Warming Response to Anthropogenic Greenhouse Gases: An Interbasin Thermostat Mechanism
Authors: Zhang Lei , Han Weiqing , Karnauskas Kristopher B. , Meehl Gerald A. , Hu Aixue , Rosenbloom Nan , Shinoda Toshiaki 
Published: September 2019

AbstractA greater warming trend of sea surface temperature in the tropical Indian Ocean than in the tropical Pacific is a robust feature found in various observational data sets. Yet this interbasin warming contrast is not present in climate models. Here we investigate the impact of tropical Indian Ocean warming on the tropical Pacific response to anthropogenic greenhouse gas warming by analyzing results from coupled model pacemaker experiments. We find that warming in the Indian Ocean induces local negative sea level pressure anomalies, which extend to the western tropical Pacific, strengthening the zonal sea level pressure gradient and easterly trades in the tropical Pacific. The enhanced trade winds reduce sea surface temperature in the eastern tropical Pacific by increasing equatorial upwelling and evaporative cooling, which offset the greenhouse gas warming. This result suggests an interbasin thermostat mechanism, through which the Indian Ocean exerts its influence on the Pacific response to anthropogenic greenhouse gas warming.
Acceleration of Interstellar Pickup He+ at Earth's Perpendicular Bow Shock
Authors: Starkey M. J. , Fuselier S. A. , Desai M. I. , Burch J. L. , Gomez R. G. , Mukherjee J. , Russell C. T. , Lai H. , Schwartz S. J. 
Published: September 2019

AbstractOn 05 December 2015 the Magnetospheric MultiScale constellation observed interstellar pickup ion distributions during an inbound crossing of Earth's perpendicular bow shock near the subsolar point, which provides new insights into shock acceleration of pickup ions throughout the heliosphere. In this study we analyze the upstream and downstream velocity distributions of H+ and He+ using data from the Hot Plasma Composition Analyzer on Magnetospheric MultiScale. We derive average two‐dimensional pitch angle distributions in the upstream and downstream field‐aligned bulk plasma frame, as well as integrated one‐dimensional velocity distributions. By comparing the upstream and downstream distributions, we find evidence of accelerated H+ and He+ downstream of the shock. By comparing measured and theoretical reflection ratios for He+, we attribute a significant part of this acceleration to a single reflection at the shock.
Combined Scattering of Radiation Belt Electrons Caused by Landau and Bounce Resonant Interactions With Magnetosonic Waves
Authors: Fu Song , Ni Binbin , Zhou Ruoxian , Cao Xing , Gu Xudong 
Published: September 2019

AbstractWe develop a full relativistic test particle code to model the combined electron scattering effect of Landau and bounce resonances with magnetosonic waves. Test particle simulations of magnetosonic wave‐electron interactions indicate that the two resonances coexist to affect radiation belt electrons at different energies and pitch angles, and the resultant combined pitch angle scattering and energy diffusion can reach the rates of ~10−4 and ~10‐5 s, respectively, for electrons ~40–500 keV at pitch angles ~   70 ° –   80° for the given wave model (~200 pT) inside the plasmapause at L = 4.5. Comparisons with the quasi‐linear theory results show that the test particle combined scattering rates are generally an order of magnitude weaker, possibly because the electrons are moved out of the Landau resonance by the advective effect of the bounce resonance. Our investigation demonstrates that the Landau and bounce resonances with magnetosonic waves cannot be treated independently or additively in terms of quasi‐linear theory to simulate the associated radiation belt electron dynamics.
A Model of Shallow Viscoelastic Relaxation for Seismically Induced Tension Cracks in the Chile‐Peru Forearc
Authors: Luo H. , Wang K. , Sone H. , He J. 
Published: September 2019

AbstractTension cracks were generated by past megathrust earthquakes along the coastal forearc of Chile‐Peru. To explain why elastic rebound in an offshore earthquake can cause widespread permanent deformation onshore, we propose a model in which the near‐surface material exhibits viscoelastic behavior, analogous to laboratory‐observed behavior of petroleum reservoir rocks. Because of near‐surface relaxation, interseismic deformation builds up stress only in the deeper crust. Elastic rebound of the deeper crust during an earthquake induces near‐surface tension to generate cracks. We numerically demonstrate the proposed mechanism using hypothetical and real megathrust earthquakes. The location of the zone of peak tension, assumed to be responsible for the crack generation, is controlled by downdip rupture termination. A rupture farther downdip or terminating more gradually causes the zone of peak tension to be farther landward and broader. The tension cracks thus may contain important information on megathrust rupture dynamics.
Central Asian Drying at 3.3 Ma Linked to Tropical Forcing?
Authors: Su Qingda , Nie Junsheng , Meng Qingquan , Heermance Richard , Gong Lisha , Luo Zeng , Wang Zhao , Zhang Rui , Garzione Carmala 
Published: September 2019

AbstractThe processes controlling middle‐latitude environmental changes are poorly understood. Both high‐latitude ice sheets and tropical oceans can affect climate and environments in middle latitudes, but separating their relative contribution is challenging. Coincidence of intensive Northern Hemisphere glaciations and increased dust accumulation rates at ~2.7 Ma on the Chinese Loess Plateau and North Pacific Ocean is often used to indicate high latitudes' dominant role on middle‐latitude climate change. Here we present new and compile available evidence from the Qaidam Basin and the Tarim Basin of central Asia demonstrating a phase of drying at ~3.3 Ma. The drying is synchronous with proposed timing of closure of the Indonesian Seaway, which has been suggested to cause significant oceanic surface heat adjustments and corresponding decreased heat and moisture transport to middle/high latitudes. These new results suggest a tropical forcing of aridification for the late Pliocene central Asian environmental evolution.
Significant Impact of Rossby Waves on Air Pollution Detected by Network Analysis
Authors: Zhang Yongwen , Fan Jingfang , Chen Xiaosong , Ashkenazy Yosef , Havlin Shlomo 
Published: September 2019

AbstractAir pollution fluctuations have been found to strongly depend on the weather dynamics. Here we identify the significant atmospheric processes that affect the local daily variability of air pollution. We develop a multilayered network analysis to detect the interlinks between the 500‐hPa geopotential height and surface air pollution in both China and the United States. We find that Rossby waves significantly affect air pollution fluctuations through the development of cyclone and anticyclone systems and further affect the local stability of the air and the winds. Some of these systems are remote (∼3,000 km) and lead to air pollution 1–2 days later. Thus, the impact of Rossby waves on human life is greater than previously believed. The rapid warming of the Arctic could slow down Rossby waves, thus increasing human health risks. Our method can help to determine the risk assessment of such extreme events and can improve potential predictability.
Ion Composition Boundary Layer Instabilities at Mars
Authors: Halekas J. S. , Ruhunusiri S. , McFadden J. P. , Espley J. R. , DiBraccio G. A. 
Published: September 2019

AbstractThe ion composition boundary layer that separates solar wind from ionospheric plasma at Mars typically contains a smooth compositional transition. However, ~10% of boundary crossings display large nonmonotonic variations in density, indicating an instability. We find that most of these instabilities occur on the flanks or downstream of the planet, and many fall into two distinct classes, which occur in different locations, under different preferred conditions. Plume events, which occur where the solar wind electric field points outward, likely represent the motion of the escaping ion plume across the spacecraft. Snowplow events, which occur where the electric field points inward, likely represent the escape of discrete parcels of plasma, which could account for ~10% of the total ion loss from Mars. Snowplow events occur under conditions that favor the development of ionospheric irregularities, which could form a seed for the snowplow mechanism that detaches and accelerates ionospheric plasma downstream.
Plug Formation Imaged Beneath the Active Craters of Sakurajima Volcano With Muography
Authors: Oláh László , Tanaka Hiroyuki K.M. , Ohminato Takao , Hamar Gergő , Varga Dezső 
Published: September 2019

AbstractSakurajima Muography Observatory captured the formation of a volcanic plug beneath the Showa crater with a spatial resolution of ∼60 m in accordance with the end of the eruption episode of Showa crater and the reactivation of Minamidake crater. The increase of average density was observed with above 3 σ standard deviation for both above the floor of Minamidake crater and beneath the floor of Showa crater, respectively, being interpreted as volcanic ejecta deposition and the formation of a volcanic plug laterally extended within a few hundreds of meters.
Sahelian Precipitation Change Induced by SST Increase: The Contrasting Roles of Regional and Larger‐Scale Drivers
Authors: Dixon Ross D. , Peyrillé Philippe , Guichard Françoise 
Published: September 2019

AbstractRepresenting the West African Monsoon is a major challenge in climate modeling because of complex mechanisms of interaction across scales. We study the monsoon precipitation response to a 4K increase in sea surface temperatures using an idealized meridional‐vertical (2D) model, which allows separating regional‐ and larger‐scale influences. The 2D simulations reproduce key features of Atmospheric Model Intercomparison Project simulations and indicate that, in response to sea surface temperature increase, large‐scale changes induce a decrease of Sahel precipitation, while regional‐scale mechanisms generate a southward shift of the rainband. Large‐scale changes moisten and warm the free troposphere, while regional circulation changes increase low‐level moisture. Precipitation in the control simulations accounts for much of the variance in precipitation change for both Atmospheric Model Intercomparison Project and 2D simulations. This response is strongly connected to the large‐scale drivers of temperature and moisture, with an additional spread associated with the formulation of the convective parameterization.
A New Perspective for Dipolarization Front Dynamics: Electromagnetic Effects of Velocity Inhomogeneity
Authors: Lin Dong , Scales Wayne A. , Ganguli Gurudas , Fu Xiangrong , Crabtree Chris , Tejero Erik , Chen Yuxi , Fletcher Alex C. 
Published: September 2019

AbstractThe stability of a quasi‐static near‐Earth dipolarization front (DF) is investigated with a two‐dimensional electromagnetic particle‐in‐cell model. Strongly localized ambipolar electric fields self‐consistently generate a highly sheared dawnward
electron drift on the kinetic scale in the DF. Electromagnetic particle‐in‐cell simulations based on the observed DF thickness and gradients of plasma/magnetic field parameters reveal that the DF is susceptible to the kinetic electron‐ion hybrid (EIH) instability driven by the strong velocity inhomogeneity. The excited waves show a broadband spectrum in the lower hybrid (LH) frequency range, which has been often observed at DFs. The wavelength is comparable to the shear scale length, and the growth rate is also in the LH frequency range, which are consistent with the EIH theory. As a result of the LH wave emissions, the velocity shear is relaxed, and the DF is broadened. When the plasma beta increases, the wave mode shifts to longer wavelengths with reduced growth rates and enhanced magnetic fluctuations although the wave power is mostly in the electrostatic regime. This study highlights the role of velocity inhomogeneity in the dynamics of DF which has been long neglected. The EIH instability is suggested to be an important mechanism for the wave emissions and steady‐state structure at the DF.
Large‐Amplitude Mountain Waves in the Mesosphere Observed on 21 June 2014 During DEEPWAVE: 1. Wave Development, Scales, Momentum Fluxes, and Environmental Sensitivity
Authors: Taylor Michael J. , Pautet Pierre‐Dominique , Fritts David C. , Kaifler Bernd , Smith Steven M. , Zhao Yucheng , Criddle Neal R. , McLaughlin Pattilyn , Pendleton William R. , McCarthy Michael P. , Hernandez Gonzalo , Eckermann Stephen D. , Doyle James , Rapp Markus , Liley Ben , Russell James M. 
Published: September 2019

AbstractA remarkable, large‐amplitude, mountain wave (MW) breaking event was observed on the night of 21 June 2014 by ground‐based optical instruments operated on the New Zealand South Island during the Deep Propagating Gravity Wave Experiment (DEEPWAVE). Concurrent measurements of the MW structures, amplitudes, and background environment were made using an Advanced Mesospheric Temperature Mapper, a Rayleigh Lidar, an All‐Sky Imager, and a Fabry‐Perot Interferometer. The MW event was observed primarily in the OH airglow emission layer at an altitude of ~82 km, over an ~2‐hr interval (~10:30–12:30 UT), during strong eastward winds at the OH altitude and above, which weakened with time. The MWs displayed dominant horizontal wavelengths ranging from ~40 to 70 km and temperature perturbation amplitudes as large as ~35 K. The waves were characterized by an unusual, “saw‐tooth” pattern in the larger‐scale temperature field exhibiting narrow cold phases separating much broader warm phases with increasing temperatures toward the east, indicative of strong overturning and instability development. Estimates of the momentum fluxes during this event revealed a distinct periodicity (~25 min) with three well‐defined peaks ranging from ~600 to 800 m2/s2, among the largest ever inferred at these altitudes. These results suggest that MW forcing at small horizontal scales (<100 km) can play large roles in the momentum budget of the mesopause region when forcing and propagation conditions allow them to reach mesospheric altitudes with large amplitudes. A detailed analysis of the instability dynamics accompanying this breaking MW event is presented in a companion paper, Fritts et al. (2019, https://doi.org/10.1029/2019jd030899).
Promyelocytic Leukemia (PML) gene regulation: implication towards curbing oncogenesis
Authors: Datta Neerajana , Islam Saimul , Chatterjee Uttara , Chatterjee Sandip , Panda Chinmay K. , Ghosh Mrinal K. 
Published: September 2019

AbstractDysregulation of PML, a significant tumor suppressor is linked with cancers of different histological origins, with a decreased expression observed with a higher tumor grade. This necessitates studying the mechanisms to maintain a stable expression of PML. However much less is known about the transcriptional regulation of PML, more so in the context of breast carcinoma. ERβ has emerged as a critical factor in understanding breast cancer, especially since a huge proportion of breast cancers are ERα− and thus insensitive to tamoxifen therapy. This study aims to uncover an unidentified mechanism of PML gene regulation and its stabilization in breast cancer via ERβ signalling and the impact on cellular apoptosis. We found that clinical expression of PML positively correlates with that of ERβ both in normal and breast carcinoma samples and inversely correlates with markers of cellular proliferation, hinting towards a possible mechanistic interdependence. Both mRNA and protein expression of PML were increased in response to ERβ overexpression on multiple human breast cancer cell lines. Mechanistically, luciferase reporter assays and chromatin-immunoprecipitation assays demonstrated that ERβ can interact with the PML promoter via ERE and AP1 sites to enhance its transcription. ERβ induced stable PML expression causes a decline of its target protein Survivin and simultaneously provides a stable docking platform leading to stabilisation of its target Foxo3a, further causing transcriptional upregulation of pro-apoptotic factors p21 and p27. Immunohistochemical analyses of cancer and normal breast tissues and functional assays conducted corroborated the findings. Collectively, our study identifies ERβ signalling as a novel mechanism for PML gene regulation in ERα− breast cancer. It also reveals bi-directional downstream effect in which ‘ERβ-PML-(Foxo3a/Survivin)’ network acts as a therapeutic axis by suppressing cellular survival and promoting cellular apoptosis in breast carcinoma.
Simulations of starspot anomalies within TESS exoplanetary transit light curves
Authors: Tregloan-Reed J. , Unda-Sanzana E. 
Published: September 2019

Context. The primary targets of the NASA Transiting Exoplanet Survey Satellite (TESS) are K and M dwarf stars within our solar neighbourhood. Young K and M dwarf stars are known to exhibit a high starspot coverage (≈50%), however, older stars are known to show fewer starspots. This implies that TESS transit light curves at 2 min cadence may contain starspot anomalies, and if so, will require transit-starspot models to determine accurately the properties of the system.
Aims. The goals are to determine if starspot anomalies can manifest in TESS transit light curves, to determine the detection limits of the starspot anomalies, and to examine the relationship between the change in flux caused by the starspot anomaly and the planetary transit.
Methods. We conducted 20 573 simulations of planetary transits around spotted stars using the transit-starspot model, PRISM. In total 3888 different scenarios were considered using three different host star spectral types, M4V, M1V, and K5V. The mean amplitude of the starspot anomaly was measured and compared to the photometric precision of the light curve to determine if the characteristic “blip” of the starspot anomaly was noticeable in the light curve.
Results. The simulations show that starspot anomalies are observable in TESS 2 min cadence data. The smallest starspot detectable in TESS transit light curves has a radius of ≈ 1900 km. The starspot detection limits for the three host stars are 4900 ± 1700 km (M4V), 13 800 ± 6000 km (M1V), and 15 900 ± 6800 km (K5V). The smallest change in flux of the starspot (ΔFspot = 0.00015 ± 0.00001) can be detected when the ratio of planetary to stellar radii k = 0.082 ± 0.004.
Conclusions. The results confirm known dependencies between the amplitude of the starspot anomaly and the photometric parameters of the light curve. The results facilitated the characterisation of the relationship between the change in flux of the starspot anomaly and the change in flux of the planetary transit for TESS transit light curves.
Surgeon Burnout: Defining, Identifying, and Addressing the New Reality
Authors: Senturk James C. , Melnitchouk Nelya 
Published: September 2019

AbstractSurgeon wellness is a multidimensional commitment that encompasses occupational, mental, physical, emotional, and social domains. Loss of professional control, autonomy, and flexibility; inefficient processes; disjointed workplace relationships and goals; excessive administrative burdens; poor work–life balance; and frustrations with medical record and order entry systems have all been associated with burnout. Described as a syndrome of emotional exhaustion, depersonalization, and loss of a sense of personal accomplishment, burnout can have myriad untoward consequences. The strong link between surgeons' personal and professional identities can lead to a perfect storm of burnout, depression, compromised patient safety and quality of care, physician job loss and career dissatisfaction, substance abuse, damage to personal relationships, and suicide. The alarming scope of this problem cannot be confined to a single specialty or practice setting and is expected to increase without much needed changes to surgeon work practices and work environments. A heightened focus on wellness in the workplace with attention to improving workflow, scheduling, collaboration, and resource allocation is a welcome step taken by several institutions and championed by professional societies. Much more research is needed to reliably gauge the overall effectiveness of these approaches, further address the nuances of burnout as it applies specifically to surgeons, and ensure that members of the surgical workforce remain at their peak throughout the duration of their careers.
ABT-737 Triggers Caspase-Dependent Inhibition of Platelet Procoagulant Extracellular Vesicle Release during Apoptosis and Secondary Necrosis In Vitro
Authors: Wei Hao , Harper Matthew T. 
Published: September 2019

AbstractPlatelet lifespan is limited by activation of intrinsic apoptosis. Apoptotic platelets are rapidly cleared from the circulation in vivo. ABT-737 triggers platelet apoptosis and is a useful tool for studying this process. However, in vitro experiments lack clearance mechanisms for apoptotic platelets. To determine whether apoptotic platelets progress to secondary necrosis, apoptosis was triggered in human platelets with ABT-737, a BH3 mimetic. Platelet annexin V (AnV) binding, release of AnV+ extracellular vesicles (EVs), and loss of plasma membrane integrity were monitored by flow cytometry. ABT-737 triggered AnV binding, indicating phosphatidylserine exposure, release of AnV+ EVs, and a slow loss of plasma membrane integrity. The latter suggests that apoptotic platelets progress to secondary necrosis in vitro. These responses were dependent on caspase activation and Ca2+ entry. Surprisingly, although intracellular Ca2+ concentration increased, AnV+ EV release was not dependent on the Ca2+-dependent protease, calpain. On the contrary, ABT-737 downregulated the ability of the Ca2+ ionophore, A23187, to trigger calpain-dependent release of AnV+ EVs. This was dependent on caspase activity as, when caspases were inhibited, ABT-737 increased the ability of A23187 to trigger AnV+ EV release. These data suggest that apoptotic platelets progress to secondary necrosis unless they are cleared. This may affect the interpretation of ABT-737-triggered signaling in platelets in vitro. Ca2+-dependent AnV+ EV release is downregulated during apoptosis in a caspase-dependent manner, which may limit the potential consequences of secondary necrotic platelets.