bluuebunny/crossref_metadata_2025_split huggingface dataset:
Time‐Varying Magnetopause Reconnection During Sudden Commencement: Global MHD Simulations
Authors: Eggington J. W. B. , Desai R. T. , Mejnertsen L. , Chittenden J. P. , Eastwood J. P. 
Published: April 2022

AbstractIn response to a solar wind dynamic pressure enhancement, the compression of the magnetosphere generates strong ionospheric signatures and a sharp variation in the ground magnetic field, termed sudden commencement (SC). While such compressions have also been associated with a contraction of the ionospheric polar cap due to the triggering of reconnection in the magnetotail, the effect of any changes in dayside reconnection is less clear and is a key component in fully understanding the system response. In this study, we explore the time‐dependent nature of dayside coupling during SC by performing global simulations using the Gorgon magnetohydrodynamic code and impact the magnetosphere with a series of interplanetary shocks with different parameters. We identify the location and evolution of the reconnection region in each case as the shock propagates through the magnetosphere, finding strong enhancement in the dayside reconnection rate and prompt expansion of the dayside polar cap prior to the eventual triggering of tail reconnection. This effect pervades for a variety of interplanetary magnetic field orientations, and the reconnection rate is most enhanced for events with higher dynamic pressure. We explain this by repeating the simulations with a large explicit resistivity, showing that compression of the magnetosheath plasma near the propagating shock front allows for reconnection of much greater intensity and at different locations on the dayside magnetopause than during typical solar wind conditions. The results indicate that the dynamic behavior of dayside coupling may render steady models of reconnection inaccurate during the onset of a severe space weather event.
Simulation of Cold Ion Transport Originating From the SED Plume Into Dayside Magnetosphere
Authors: Qiao Zheng , Yuan Zhigang , Tu Jiannan 
Published: April 2022

AbstractIn this study, based on the Dynamic‐Kinetic Fluid (DyFK) model, we conduct simulations on the field‐aligned transport of cold ions (<1 eV) within three independent closed flux tubes from different starting points (L = 3.0 Re, L = 3.122 Re and L = 3.5 Re, respectively) during the 2015 St. Patrick's Day storm. These flux tubes magnetically connect the plasmaspheric plume with the ionospheric Storm Enhanced Density (SED) plume but drift toward the dayside magnetopause under E×B effects. Meanwhile, we can obtain the density variations of three ions species (H+, O+, and He+, respectively) around the flux tubes' apex (at the magnetic equator) as a function of the L shell. The simulations present the temporal evolution of cold plasma along these drifting flux tubes. We found that with increasing initial L shell location of the flux tube, there are more ionospheric cold light ions (H+ and He+) flowing into the equatorial region while the inflows of cold heavy ions (O+) toward the equator decrease. As the simulated flux tube drifts toward dayside magnetopause from the main plasmasphere (L = 3.0 Re), the SED sourced heavy ions pile up near the magnetic equator at low L shells (L < 4.0 Re) due to gravitational effects, while the light ions rapidly reach density equilibrium along the flux tube. With the flux tube drifting beyond L > 4.0 Re, the piled‐up cold heavy ions will later transport into the magnetic equatorial region and furnish the dayside magnetosphere, demonstrating that the SED is another supplier of magnetospheric cold heavy ions (O+).
Dual Sounding Rocket and C/NOFS Satellite Observations of DC Electric Fields and Plasma Density in the Equatorial E‐ and F‐Region Ionosphere at Sunset
Authors: Pfaff R. , Kudeki E. , Freudenreich H. , Rowland D. , Larsen M. , Klenzing J. 
Published: April 2022

AbstractE × B plasma drifts and plasma number density were measured on two NASA rockets launched simultaneously at sunset from Kwajalein Atoll with apogees of 182 and 331 km, with similar, coincident measurements gathered on the Communications/Navigation Outage Forecasting System (C/NOFS) satellite at 390 km. The combined measurements portray a highly dynamic ionosphere in a narrow range of local time and altitude, providing evidence of vortex‐like motions. Although the vertical plasma drift was upwards, its magnitude was not constant, increasing between ∼150 and 250 km altitude where the plasma density was reduced. The zonal plasma drifts displayed a shear with altitude, changing from eastward to westward flow below 270 km, coincident with the larger upward drifts and consistent with the maintenance of the vortex flow. The plasma density on the western flank was highly structured compared to the eastern flank, despite the fact that the western region corresponded to slightly earlier local times. These observations illustrate that the low latitude ionosphere at sunset must be considered as an ensemble of interconnected flows encompassing an evolving “theater,” as opposed to a background that simply unfolds linearly with respect to local time. The observations also underscore how satellites at high altitudes do not capture the highly dynamic ionosphere and thermosphere at the lower altitudes which are critical for understanding the electrodynamics system. Such motions set the stage for large scale plasma instabilities to form later in the evening, as observed by radars at Kwajalein and subsequent passes of the C/NOFS satellite.
A Comparative Study on the Factors Controlling the Cusp Auroral Intensity Between the Northern and Southern Hemispheres
Authors: Qiu Hui‐Xuan , Han De‐Sheng , Zhang Hong‐Da , Yang Hui‐Gen , Feng Hui‐Ting , Yu Xi , Shi Run , Zhou Su , Zhang Y.‐L. 
Published: April 2022

AbstractThe previous study has indicated that the interplanetary magnetic field (IMF) By and solar wind flow speed (Vsw) have crucial effects on the cusp auroral intensity in the Northern Hemisphere. However, it is not clear how these factors influence the cusp aurora in the Southern Hemisphere. Using DMSP/SUSSI observations from 2004 to 2017 during non‐storm periods, we compared the factors affecting the intensity of cusp aurora between the Northern and Southern Hemispheres by dividing the observations into weak‐ and intense‐emission events. We found that the auroral intensity in the southern cusp: (a) has a positive correlation with solar wind power input, (b) is statistically weak under southward IMF conditions, and (c) is critically controlled by the IMF By and Vsw. These results are essentially consistent with those obtained in the Northern Hemisphere. However, the IMF By effect shows apparent interhemispheric asymmetry, that is, the IMF By effect reaches the maximum at 2 nT in the Northern Hemisphere, but at −2 nT in the Southern Hemisphere. Further analysis shows that the 2‐nT deviations disappear after dividing all events by season and the IMF By distributions of intense‐emission events show clear seasonal difference. Based on these results, we suggest that the dependence of the cusp auroral intensity on the IMF By is not only controlled by −Vsw × By field, but also affected by season.
Influence of the Quasi‐Biennial Oscillation on the Spatial Structure of the Wintertime Arctic Oscillation
Authors: Cai Qingyu , Chen Wen , Chen Shangfeng , Ma Tianjiao , Garfinkel Chaim I. 
Published: April 2022

AbstractThis study reveals that the Quasi‐Biennial Oscillation (QBO) has a marked impact on the spatial structure of the Arctic Oscillation (AO) in boreal winter. In particular, the North Pacific center (NPC) of the AO is stronger during the westerly phase of the QBO (WQBO) than the easterly phase of the QBO (EQBO). In other words, the variability associated with the AO over the North Pacific is stronger in WQBO years than EQBO years, even though the overall variability is insensitive to QBO phase. The QBO is suggested to influence the spatial pattern of the winter AO mainly via modulating the intensity of the stratospheric polar vortex, with a stronger stratospheric polar vortex during WQBO than EQBO years. A stronger stratospheric polar vortex can lead to more planetary wave refraction and facilitate the eastward propagation of wave activity flux from the mid‐latitude North Pacific to the North Atlantic. Thus an enhanced connection between North Pacific and North Atlantic atmospheric variability is established, and a more prominent NPC of the AO occurs in WQBO years. In addition, the modulation of the AO structure by the QBO and the associated physical process is supported by output from the CNRM‐CM6‐1 model. Our results indicate that, for seasonal climate prediction in North America based on the AO, WQBO leads to a larger predictable signal while EQBO leads to reduced skill.
Effective Radiative Forcings Due To Anthropogenic Emission Changes Under Covid‐19 and Post‐Pandemic Recovery Scenarios
Authors: Yu Xiaochao , Zhang Hua , Xie Bing , Wang Zhili , Zhao Shuyun , Zhao Defeng 
Published: April 2022

AbstractWith the continuation of the Coronavirus Disease 2019 (Covid‐19) pandemic, the impacts of this catastrophe on anthropogenic emissions are no longer limited to its early stage. This study quantitatively estimates effective radiative forcings (ERFs) due to anthropogenic well‐mixed greenhouse gases (WMGHGs) and aerosols for the period 2020–2050 under the three latest Covid‐19 economic‐recovery scenarios using an aerosol‐climate model. The results indicate that reductions in both WMGHG and aerosol emissions under the Covid‐19 green recoveries lead to increases ranging from 0 to 0.3 W m−2 in global annual mean anthropogenic ERF over the period 2020–2050 relative to the Shared Socioeconomic Pathway 2‐4.5 scenario (the baseline case). These positive ERFs are mainly attributed to the rapid and dramatic decreases in atmospheric aerosol content that increase net shortwave radiative flux at the top of atmosphere via weakening the direct aerosol effect and low cloud cover. At the regional scale, reductions in aerosols contribute to positive ERFs throughout the Northern Hemisphere, while the decreased WMGHGs dominate negative ERFs over the areas away from aerosol pollution, such as the Southern Hemisphere oceans. This drives a strong interhemispheric contrast of ERFs. In contrast, the increased anthropogenic emissions under the fossil‐fueled recovery scenario lead to an increase of 0.3 W m−2 in global annual mean ERF in 2050 compared with the baseline case, primarily due to the contribution of WMGHG ERFs. The regional ERF changes are highly dependent on local cloud radiative effects.
Observed Mixing at the Flanks of Maud Rise in the Weddell Sea
Authors: Mohrmann M. , Swart S. , Heuzé C. 
Published: April 2022

AbstractMaud Rise is a seamount in the eastern Weddell Sea and the location of polynyas and a persistent halo of reduced sea ice. We present novel in situ data from two profiling floats with up to daily resolved hydrographic profiles in this region. The water properties below the mixed layer of the Maud Rise region are significantly correlated with bathymetric depth; thus, the Maud Rise flank defines the front between the Warm Deep Water of the abyssal ocean and the colder Taylor cap over Maud Rise. We analyze the spiciness curvature in density space to quantify the observed frequency or magnitude of intrusions, which are substantially increased along the flanks of Maud Rise. These intrusions are indicative of enhanced lateral and vertical mixing along heavily sloping isopycnals, creating favorable conditions for thermobaric and double diffusive convection and likely facilitating the formation of the Maud Rise halo and polynyas.
Machine Learning Gravity Wave Parameterization Generalizes to Capture the QBO and Response to Increased CO2
Authors: Espinosa Zachary I. , Sheshadri Aditi , Cain Gerald R. , Gerber Edwin P. , DallaSanta Kevin J. 
Published: April 2022

AbstractWe present single‐column gravity wave parameterizations (GWPs) that use machine learning to emulate non‐orographic gravity wave (GW) drag and demonstrate their ability to generalize out‐of‐sample. A set of artificial neural networks (ANNs) are trained to emulate the momentum forcing from a conventional GWP in an idealized climate model, given only one view of the annual cycle and one phase of the Quasi‐Biennial Oscillation (QBO). We investigate the sensitivity of offline and online performance to the choice of input variables and complexity of the ANN. When coupled with the model, moderately complex ANNs accurately generate full cycles of the QBO. When the model is forced with enhanced CO2, its climate response with the ANN matches that generated with the physics‐based GWP. That ANNs can accurately emulate an existing scheme and generalize to new regimes given limited data suggests the potential for developing GWPs from observational estimates of GW momentum transport.
Localizing the Southern Ocean Biogeochemical Divide
Authors: Xie Yinghuan , Tamsitt Veronica , Bach Lennart T. 
Published: April 2022

AbstractThe meridional overturning circulation consists of an upper and lower cell. The Southern Ocean Biogeochemical Divide (SOBD) is the boundary between the two cells in the surface of the Southern Ocean, but its location is poorly constrained. Localizing the SOBD is important because biological nutrient utilization north and south of the SOBD have fundamentally different consequences for global ocean primary production and carbon sequestration. Here, we aim to localize the SOBD by releasing virtual Lagrangian particles south of 40°S in an eddying ocean sea‐ice model and compare simulation results with observations. We find that the SOBD is a circumpolar band, where different sectors are shaped by different oceanographic features: (a) Ekman transport, (b) the γ = 27.6 kg m−3 neutral density outcrop, and (c) fronts associated with the Antarctic Circumpolar Current. Our findings help to understand how nutrient utilization in different parts of the Southern Ocean affects the biologically driven carbon sequestration.
A flexible and wearable NO2 gas detection and early warning device based on a spraying process and an interdigital electrode at room temperature
Authors: Zhang Fuzheng , Lin Qijing , Han Feng , Wang Zuowei , Tian Bian , Zhao Libo , Dong Tao , Jiang Zhuangde 
Published: April 2022

AbstractFlexible sensors used to detect NO2 gas generally have problems such as poor repeatability, high operating temperature, poor selectivity, and small detection range. In this work, a new spraying platform with a simple structure, low cost, and good film-forming consistency was designed and built to make a sensitive film (rGO/SnO2) for NO2 gas sensors. The relationship between the solid content of rGO and SnO2 nanoparticles, annealing temperature, and sensor performance was studied. The results show that the interdigital electrode-sensitive film formed by spraying 0.25 ml of a 0.4 wt% rGO/SnO2 mixture and annealing at 250 °C exhibited the best comprehensive performance for NO2 detection. The sensor’s response value for 100 ppm NO2 gas was 0.2640 at room temperature (25 °C), and the response time and recovery time were 412.4 s and 587.3 s, respectively. In the range of 20–100 ppm, the relationship between the response and NO2 concentration was linear, and the correlation coefficient was 0.9851. In addition, a soft-monitoring node module with an overlimit warning function for NO2 gas was designed and manufactured based on flexible electronics. Finally, the flexible sensor and node module were embedded into woven fabric that could be used to make a mask or a watch that could detect NO2 gas, realizing the practical application of flexible NO2 gas sensors in the field of wearable electronics.
Introducing the brain erythropoietin circle to explain adaptive brain hardware upgrade and improved performance
Authors: Ehrenreich Hannelore , Garcia-Agudo Laura Fernandez , Steixner-Kumar Agnes A. , Wilke Justus B. H. , Butt Umer Javed 
Published: April 2022

PrefaceExecutive functions, learning, attention, and processing speed are imperative facets of cognitive performance, affected in neuropsychiatric disorders. In clinical studies on different patient groups, recombinant human (rh) erythropoietin (EPO) lastingly improved higher cognition and reduced brain matter loss. Correspondingly, rhEPO treatment of young rodents or EPO receptor (EPOR) overexpression in pyramidal neurons caused remarkable and enduring cognitive improvement, together with enhanced hippocampal long-term potentiation. The ‘brain hardware upgrade’, underlying these observations, includes an EPO induced ~20% increase in pyramidal neurons and oligodendrocytes in cornu ammonis hippocampi in the absence of elevated DNA synthesis. In parallel, EPO reduces microglia numbers and dampens their activity and metabolism as prerequisites for undisturbed EPO-driven differentiation of pre-existing local neuronal precursors. These processes depend on neuronal and microglial EPOR. This novel mechanism of powerful postnatal neurogenesis, outside the classical neurogenic niches, and on-demand delivery of new cells, paralleled by dendritic spine increase, let us hypothesize a physiological procognitive role of hypoxia-induced endogenous EPO in brain, which we imitate by rhEPO treatment. Here we delineate the brain EPO circle as working model explaining adaptive ‘brain hardware upgrade’ and improved performance. In this fundamental regulatory circle, neuronal networks, challenged by motor-cognitive tasks, drift into transient ‘functional hypoxia’, thereby triggering neuronal EPO/EPOR expression.
Myeloablative conditioning with thiotepa-busulfan-fludarabine does not improve the outcome of patients transplanted with active leukemia: final results of the GITMO prospective trial GANDALF-01
Authors: Bonifazi Francesca , Pavoni Chiara , Peccatori Jacopo , Giglio Fabio , Arpinati Mario , Busca Alessandro , Bernasconi Paolo , Grassi Anna , Iori Anna Paola , Patriarca Francesca , Brunello Lucia , Di Grazia Carmen , Carella Angelo Michele , Cilloni Daniela , Picardi Alessandra , Proia Anna , Santarone Stella , Sorasio Roberto , Carluccio Paola , Chiusolo Patrizia , Cupri Alessandra , Luppi Mario , Nozzoli Chiara , Baronciani Donatella , Casini Marco , Grillo Giovanni , Musso Maurizio , Onida Francesco , Palazzo Giulia , Parma Matteo , Tringali Stefania , Vacca Adriana , Vallisa Daniele , Sacchi Nicoletta , Oldani Elena , Masciulli Arianna , Gheorghiu Angela , Girmenia Corrado , Martino Massimo , Bruno Benedetto , Rambaldi Alessandro , Ciceri Fabio ,   on behalf of GITMO
Published: April 2022

AbstractThe outcome of refractory/relapsed (R/R) acute leukemias is still dismal and their treatment represents an unmet clinical need. However, allogeneic transplantation (allo-HSCT) remains the only potentially curative approach in this setting. A prospective study (GANDALF-01, NCT01814488; EUDRACT:2012-004008-37) on transplantation with alternative donors had been run by GITMO using a homogeneous myeloablative conditioning regimen with busulfan, thiotepa and fludarabine while GVHD prophylaxis was stratified by donor type. The study enrolled 101 patients; 90 found an alternative donor and 87 ultimately underwent allo-HSCT. Two-year overall survival of the entire and of the transplant population (primary endpoint) were 19% and 22%, without significant differences according to disease, donor type and disease history (relapsed vs refractory patients). Two-year progression-free survival was 19% and 17% respectively. The cumulative incidences of relapse and non-relapse mortality were 49% and 33% at two years. Acute grade II-IV and chronic GVHD occurred in 23 and 10 patients. Dose intensification with a myeloablative two-alkylating regimen as sole strategy for transplanting R/R acute leukemia does seem neither to improve the outcome nor to control disease relapse. A pre-planned relapse prevention should be included in the transplant strategy in this patient population.
Targeted P2X7/NLRP3 signaling pathway against inflammation, apoptosis, and pyroptosis of retinal endothelial cells in diabetic retinopathy
Authors: Kong Hui , Zhao Hongran , Chen Tianran , Song Yanling , Cui Yan 
Published: April 2022

AbstractRetinal endothelial cells (RECs) are the primary target cells for diabetes-induced vascular damage. The P2X7/NLRP3 pathway plays an essential role in amplifying inflammation via an ATP feedback loop, promoting the inflammatory response, pyroptosis, and apoptosis of RECs in the early stages of diabetic retinopathy induced by hyperglycemia and inflammation. 3TC, a type of nucleoside reverse transcriptase inhibitor, is effective against inflammation, as it can targeting formation of the P2X7 large pore formation. Hence, our aim was to evaluated the anti-inflammatory effects and potential mechanisms of action of 3TC in vitro in retinal microvascular endothelial cells treated with high-glucose (HG) and lipopolysaccharide (LPS), as well as in vivo in the retinas of C57BL/6J male mice with streptozotocin-induced diabetes. The expression of inflammasome-related proteins P2X7 and NLRP3, and apoptosis in the retinas of 3TC-treated diabetic mice were compared to those of untreated diabetic mice. Furthermore, the anti-inflammatory, anti-apoptotic, and anti-pyroptotic effects of 3TC were evaluated in vitro in cultured mice retinal endothelial cells. Co-application of HG and LPS significantly increased the secretion of IL-6, IL-1β, and TNF-α, and ATP levels, whereas 3TC decreased cell inflammation, apoptosis, and pyroptosis. Inhibition of P2X7R and NLRP3 inflammasome activation decreased NLRP3 inflammasome-mediated injury. 3TC prevented cytokine and ATP release following co-application of HG and LPS/BzATP. Our findings provide new insights regarding the mechanisms of action of 3TC in diabetic environment-induced retinal injury, including apoptosis and pyroptosis.
Attribution of 2020 hurricane season extreme rainfall to human-induced climate change
Authors: Reed Kevin A. , Wehner Michael F. , Zarzycki Colin M. 
Published: April 2022

AbstractThe 2020 North Atlantic hurricane season was one of the most active on record, causing heavy rains, strong storm surges, and high winds. Human activities continue to increase the amount of greenhouse gases in the atmosphere, resulting in an increase of more than 1 °C in the global average surface temperature in 2020 compared to 1850. This increase in temperature led to increases in sea surface temperature in the North Atlantic basin of 0.4–0.9 °C during the 2020 hurricane season. Here we show that human-induced climate change increased the extreme 3-hourly storm rainfall rates and extreme 3-day accumulated rainfall amounts during the full 2020 hurricane season for observed storms that are at least tropical storm strength (>18 m/s) by 10 and 5%, respectively. When focusing on hurricane strength storms (>33 m/s), extreme 3-hourly rainfall rates and extreme 3-day accumulated rainfall amounts increase by 11 and 8%, respectively.