bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mid‐Latitude Spread‐F Structures Over the Geomagnetic Low‐Mid Latitude Transition Region: An Observational Evidence
Authors: Sivakandan M. , Mondal S. , Sarkhel S. , Chakrabarty D. , Sunil Krishna M. V. , Chaitanya P. Pavan , Patra A. K. , Choudhary R. K. , Pant T. K. , Upadhayaya A. K. , Sori Takuya 
Published: April 2020

AbstractAn observational evidence of a unique plasma depletion event was captured by an O(1D) 630.0 nm airglow imager on 13 June 2018 over a transition region of geomagnetic low‐mid latitude, Hanle, Leh Ladakh, India (32.77°N, 78.97°E; Mlat. ~24.1°N). The observed plasma depletion structures are tilted at an angle of 13° ± 2° west of the geomagnetic north and drifted toward west. Collocated Global Navigation Satellite System‐Total Electron Content measurements confirm that the structures are indeed associated with TEC depletions. Simultaneous ionosonde measurements from Delhi, India (28.70°N, 77.10°E; Mlat. ~20.2°N) shows spread‐F signatures confirming that these structures are associated with the ionospheric irregularities. Interestingly, radar observations over the geomagnetic low‐latitude station Gadanki, India (13.5°N; 79.2°E; Mlat. ~6.5°N) reveal the absence of equatorial plasma bubbles on this night. Therefore, these observations strongly suggest that the observed structures in the airglow images over Hanle are associated with mid‐latitude spread‐F (MSF). These MSF structures are possibly affected by the shear in the zonal plasma drift that forces the field aligned plasma irregularity structures to tilt toward west. These observations, for the first time, bring out the presence of MSF structures over geomagnetic low‐mid latitude transition region. It is suggested that the plasma distribution over low latitudes plays an important role in the occurrence of MSF structures over this transition region. Understanding the source and characteristics of the plasma irregularity structures over this transition region can help in understanding the spatio‐temporal evolution of global L‐band scintillation in a better way.
Quantifying the Effect of Plasmaspheric Hiss on the Electron Loss From the Slot Region
Authors: Kim Kyung‐Chan , Shprits Yuri , Wang Dedong 
Published: April 2020

AbstractWe present global statistical models of both wave amplitude and wave normal angle (WNA) of plasmaspheric hiss using Van Allen Probe‐A observations. They utilize the time history of solar wind parameters, that is, interplanetary magnetic field BZ and solar wind speed, and the AE index for each measurement of hiss waves as inputs. The solar wind parameter‐based model generally results in higher performance than using only the AE index as an input. Both observations and model results reveal a clear dependence of hiss wave distribution on the magnetic local time (MLT): Higher amplitudes with field‐aligned (<30o) WNAs occur more frequently on the dayside than on the nightside. Such a tendency does not depend on magnetic latitude (MLAT), but slightly larger WNAs with a relatively low amplitude frequently appear for larger MLAT (>10o). We also examine how significantly the electron loss rates in the slot region can be changed by incorporating the model output of hiss waves into a diffusive transport simulation. Simulation results show that during a typical timescale (roughly a couple of days) of a corotating interaction region‐driven storm, the nightside hiss waves with larger WNA (>30o) do not contribute to the electron loss in the slot region due to their low amplitude and large WNA, while dayside hiss with WNAs less than 30o and comparatively higher amplitudes leads to a fast drop in flux, especially for electrons of a few hundred keV.
Fault Control on a Thermal Anomaly: Conceptual and Numerical Modeling of a Low‐Temperature Geothermal System in the Southern Alps Foreland Basin (NE Italy)
Authors: Pola Marco , Cacace Mauro , Fabbri Paolo , Piccinini Leonardo , Zampieri Dario , Torresan Filippo 
Published: April 2020

AbstractThe interest on low‐temperature geothermal resources is progressively increasing since their renewability and widespread availability. Despite their frequency, these resources and their development have been only partially investigated. This paper unravels the major physical processes driving a low‐temperature geothermal resource in NE Italy (Euganean Geothermal System) through conceptual and numerical modeling. Dense fracturing associated to regional fault zones and a relay ramp enhances regional to local flow of thermal waters. Their rapid upwelling in the Euganean Geothermal Field is favored by open extensional fractures deforming the relay ramp. The water (65–86 °C) is intensively exploited for balneotherapy, rendering it a profitable resource. Three‐dimensional coupled flow and heat transport numerical simulations based on this conceptual model are performed. Despite the presence of a uniform basal heat flow, a thermal anomaly corresponding to field observations develops in the modeling domain reproducing the relay ramp. Intensive fracturing extending across a wide area and a slightly anomalous heat flow favors a local increase in convection that drives the upwelling of deep‐seated hot waters. The simulations corroborate and refine the conceptual model, revealing that water of up to 115 °C is likely to be found in the unexplored part of the thermal field. This study furthers knowledge on fault‐controlled low‐temperature geothermal resources where the geological setting could enhance local convection without anomalous heat flows, creating temperatures favorable for energy production. Conceptual and numerical modeling based on solid geological and hydrogeological reconstructions can offer a support tool for further detailed explorations of these prominent resources.
Volcano‐Tectonic Interactions at Sabancaya Volcano, Peru: Eruptions, Magmatic Inflation, Moderate Earthquakes, and Fault Creep
Authors: MacQueen Patricia , Delgado Francisco , Reath Kevin , Pritchard Matthew E. , Bagnardi Marco , Milillo Pietro , Lundgren Paul , Macedo Orlando , Aguilar Victor , Ortega Mayra , Anccasi Rosa , Lazarte Zerpa Ivonne Alejandra , Miranda Rafael 
Published: April 2020

AbstractWe present evidence of volcano‐tectonic interactions at Sabancaya volcano that we relate to episodic magma injection and high regional fluid pore pressures. We present a surface deformation time series at Sabancaya including observations from ERS‐1/2, Envisat, Sentinel‐1, COSMO‐SkyMed, and TerraSAR‐X that spans June 1992 to February 2019. These data show deep‐seated inflation northwest of Sabancaya from 1992–1997 and 2013–2019, as well as creep and rupture on multiple faults. Afterslip on the Mojopampa fault following a 2013 MW 5.9 earthquake is anomalously long lived, continuing for at least 6 years. The best fit fault plane for the afterslip is right‐lateral motion on an EW striking fault at 1 km depth. We also model surface deformation from two 2017 earthquakes (MW 4.4 and MW 5.2) on unnamed faults, for which the best fit models are NW striking normal faults at 1–2 km depth. Our best fit model for a magmatic inflation source (13 km depth, volume change of 0.04 to 0.05 km3 yr−1) induces positive Coulomb static stress changes on these modeled fault planes. Comparing these deformation results with evidence from satellite thermal and degassing data, field observations, and seismic records, we interpret strong pre‐eruptive seismicity at Sabancaya as a consequence of magmatic intrusions destabilizing tectonic faults critically stressed by regionally high fluid pressures. High fluid pressure likely also promotes fault creep driven by static stress transfer from the inflation source. We speculate that combining high pore fluid pressures with sufficiently large, offset magmatic inflation can promote strong earthquakes during volcanic unrest.
Spatial and Temporal Variability of the North Atlantic Eddy Field From Two Kilometric‐Resolution Ocean Models
Authors: Ajayi Adekunle , Le Sommer Julien , Chassignet Eric , Molines Jean‐Marc , Xu Xiaobiao , Albert Aurelie , Cosme Emmanuel 
Published: April 2020

AbstractOcean circulation is dominated by turbulent geostrophic eddy fields with typical scales ranging from 10 to 300 km. At mesoscales (>50 km), the size of eddy structures varies regionally following the Rossby radius of deformation. The variability of the scale of smaller eddies is not well known due to the limitations in existing numerical simulations and satellite capability. Nevertheless, it is well established that oceanic flows (<50 km) generally exhibit strong seasonality. In this study, we present a basin‐scale analysis of coherent structures down to 10 km in the North Atlantic Ocean using two submesoscale‐permitting ocean models, a NEMO‐based North Atlantic simulation with a horizontal resolution of 1/60 (NATL60) and an HYCOM‐based Atlantic simulation with a horizontal resolution of 1/50 (HYCOM50). We investigate the spatial and temporal variability of the scale of eddy structures with a particular focus on eddies with scales of 10 to 100 km, and examine the impact of the seasonality of submesoscale energy on the seasonality and distribution of coherent structures in the North Atlantic. Our results show an overall good agreement between the two models in terms of surface wave number spectra and seasonal variability. The key findings of the paper are that (i) the mean size of ocean eddies show strong seasonality; (ii) this seasonality is associated with an increased population of submesoscale eddies (10–50 km) in winter; and (iii) the net release of available potential energy associated with mixed layer instability is responsible for the emergence of the increased population of submesoscale eddies in wintertime.
Impact of Afforestation on Atmospheric Recharge to Groundwater in a Semiarid Area
Authors: Huang Tianming , Pang Zhonghe , Yang Shuo , Yin Lihe 
Published: April 2020

AbstractWhile the global forest area is generally decreasing, various afforestation projects have been implemented, including the large‐scale Three‐North Afforestation Program (TNAP) and the Conversion of Cropland to Forest Program in China, under which 0.63 million square kilometers of trees have been planted. The large‐scale land use and cover change (LUCC) would affect the redistribution of precipitation and change the water cycle, especially groundwater recharge. The chloride mass balance (CMB) between precipitation and soil water/groundwater is the most widely used technique to estimate the recharge in arid and semiarid areas. However, in the case of decreased recharge following LUCC, a new equilibrium of water and chloride flux is not easily reached and the identification of steady state is the premise to use CMB. This study provided a method to assess the steady state by comparing the history of LUCC and chloride cumulative age at sampling depth and by checking the breaks in the slope of the line for cumulative chloride and soil water. The case study in the Mu Us Sandy Land, affected by the TNAP, shows that soil profiles beneath sparse grassland, shrubland, and woodland have reached steady state. However, new equilibrium has not been reached in the soil profiles beneath the dense shrubland. The estimated recharge rates beneath the plantations represent reductions from 33% to >90% relative to the surrounding bare sandy land (50–54 mm/year). The results highlight the unfavorable effects of some afforestation and ecological rehabilitation approaches in arid and semiarid areas on regional groundwater resources.
The Global Land Carbon Cycle Simulated With ISBA‐CTRIP: Improvements Over the Last Decade
Authors: Delire Christine , Séférian Roland , Decharme Bertrand , Alkama Ramdane , Calvet Jean‐Christophe , Carrer Dominique , Gibelin Anne‐Laure , Joetzjer Emilie , Morel Xavier , Rocher Matthias , Tzanos Diane 
Published: April 2020

AbstractWe present the latest version of the ISBA‐CTRIP land surface system, focusing on the representation of the land carbon cycle. We review the main improvements since the year 2012, mainly added modules for wild fires, carbon leaching through soil and transport of dissolved organic carbon to the ocean, and land cover changes but also improved representation of photosynthesis, respiration, and plant functional types. This version of ISBA‐CTRIP is fully described in terms of land carbon pools, fluxes, and their interactions. Results are compared with the previous version in an off‐line mode forced by observed climate during the historical time period. The two simulations are presented to demonstrate the model performance compared to an ensemble of observed and observation‐derived data sets for gross and net primary productivity, heterotrophic and autotrophic respiration, above and below ground biomass, litter, and soil carbon pools. New developments specific to the new version such as burned area, fire emissions, carbon leaching, and land cover are also validated against observations. The results show clearly that the latest version of ISBA‐CTRIP outperforms the former version and reproduces generally well the observed mean spatial patterns in carbon pools and fluxes, as well as the seasonal cycle of leaf area index. The trends of the global fluxes over the last 50 years agree with other global models and with available estimates. This comparison gives us confidence that the model represents the main processes involved in the terrestrial carbon cycle and can be used to explore future global change projections.
High‐Resolution Gridded Population Projections for China Under the Shared Socioeconomic Pathways
Authors: Chen Yimin , Li Xia , Huang Kangning , Luo Ming , Gao Minyi 
Published: April 2020

AbstractGridded population projections consistent with the shared socioeconomic pathways (SSPs) are critical for the studies of climate change impacts and their mitigation. Existing gridded population projections under the SSPs have relatively coarse resolution and issue of overestimation in populated areas, which further bias the analysis of climate change impacts. In this study, we proposed a scheme by integrating high‐resolution historical population maps and machine learning models to predict future built‐up land and population distributions, which were rendered consistent with the SSPs. Using this proposed method in China, we generated a set of 100‐m SSPs population maps for China from 2015 to 2050 at 5‐year intervals. Our projections revealed different spatial structures for the population distribution at the grid level and three modes of provincial population change across the five SSPs from 2015 to 2050. By applying the 100‐m SSPs population grids, we showed that, from 2015 to 2050, exposure to extreme heat in China will increase by 121–136% and 164–191% under the representative concentration pathways 4.5 and 8.5, respectively. We also found a severe spatial bias in the existing 1/8 ° SSPs population grids, i.e., 30–43% of the estimated population is wrongly allocated in cropland, forest, and pastureland. This bias results in substantial underestimation of extreme heat exposure in high‐density metropolitan areas and overestimation in medium and low‐density areas.
MSCs ameliorate hepatocellular apoptosis mediated by PINK1-dependent mitophagy in liver ischemia/reperfusion injury through AMPKα activation
Authors: Zheng Jun , Chen Liang , Lu Tongyu , Zhang Yingcai , Sui Xin , Li Yang , Huang Xuna , He Liying , Cai Jianye , Zhou Chaorong , Liang Jinliang , Chen Guihua , Yao Jia , Yang Yang 
Published: April 2020

AbstractHepatocyte apoptosis is the main pathophysiological process underlying liver ischemia/reperfusion (I/R) injury. Mitochondrial abnormalities have a vital role in hepatocellular damage. The hepatoprotective effects of mesenchymal stem cells (MSCs) have been previously demonstrated. In this study, we aim to investigate the effect and potential mechanism of MSCs against liver I/R injury. Effects of MSCs were studied in mice liver I/R injury model and in a hypoxia/reoxygenation (H/R) model of L02 hepatocytes. The potential mechanisms of MSCs on these in vivo and in vitro I/R-induced hepatocellular apoptosis models were studies. Accompanied by the improvement of hepatic damage, MSCs exhibited capabilities of controlling mitochondrial quality, shown by reduced mitochondrial reactive oxygen species (mtROS) overproduction, decreased the accumulation of mitochondrial fragmentation, restored ATP generation and upregulated mitophagy. Furthermore, we descripted a potential mechanism of MSCs on upregulating mitophagy and found that the reduced Parkin and PINK1 expression and inactivated AMPKα pathway were observed in the liver tissue in I/R model. These effects were reversed by MSCs treatment. In vitro study showed that MSC-conditioned medium (MSC-CM) suppressed hepatocellular apoptosis and inhibited mtROS accumulation in the H/R environment. And these effects of MSC-CM were partially blocked after the cells were transfected with PINK1 siRNA or added with dorsomorphin. Collectively, our findings provide a novel pharmacological mechanism that MSCs exert hepatoprotective effect in liver I/R injury via upregulating PINK1-dependent mitophagy. In addition, this effect might be attributed to the modulation of AMPKα activation.
Enhanced fatty acid oxidation provides glioblastoma cells metabolic plasticity to accommodate to its dynamic nutrient microenvironment
Authors: Kant Shiva , Kesarwani Pravin , Prabhu Antony , Graham Stewart F. , Buelow Katie L. , Nakano Ichiro , Chinnaiyan Prakash 
Published: April 2020

AbstractDespite advances in molecularly characterizing glioblastoma (GBM), metabolic alterations driving its aggressive phenotype are only beginning to be recognized. Integrative cross-platform analysis coupling global metabolomic and gene expression profiling on patient-derived glioma identified fatty acid β-oxidation (FAO) as a metabolic node in GBM. We determined that the biologic consequence of enhanced FAO is directly dependent upon tumor microenvironment. FAO serves as a metabolic cue to drive proliferation in a β-HB/GPR109A dependent autocrine manner in nutrient favorable conditions, while providing an efficient, alternate source of ATP only in nutrient unfavorable conditions. Rational combinatorial strategies designed to target these dynamic roles FAO plays in gliomagenesis resulted in necroptosis-mediated metabolic synthetic lethality in GBM. In summary, we identified FAO as a dominant metabolic node in GBM that provides metabolic plasticity, allowing these cells to adapt to their dynamic microenvironment. Combinatorial strategies designed to target these diverse roles FAO plays in gliomagenesis offers therapeutic potential in GBM.
Default polyfunctional T helper 1 response to ample signal 1 alone
Authors: Danelli Luca , Cornish Georgina , Merkenschlager Julia , Kassiotis George 
Published: April 2020

AbstractCD4+ T cells integrate well-defined signals from the T-cell receptor (TCR) (signal 1) and a host of costimulatory molecules (signal 2) to initiate clonal expansion and differentiation into diverse functional T helper (Th) subsets. However, our ability to guide the expansion of context-appropriate Th subsets by deploying these signals in vaccination remains limited. Using cell-based vaccines, we selectively amplified signal 1 by exclusive presentation of an optimized peptide:MHC II (pMHC II) complex in the absence of classic costimulation. Contrary to expectations, amplified signal 1 alone was strongly immunogenic and selectively expanded high-affinity TCR clonotypes, despite delivering intense TCR signals. In contrast to natural infection or standard vaccines, amplified signal 1, presented by a variety of professional and nonprofessional antigen-presenting cells (APCs), induced exclusively polyfunctional Th1 effector and memory cells, which protected against retroviral infection and tumor challenge, and expanded tumor-reactive CD4+ T cells otherwise rendered unresponsive in tumor-bearing hosts. Together, our findings uncover a default Th1 response to ample signal 1 and offer a means to selectively prime such protective responses by vaccination.
Using an integrative machine learning approach utilising homology modelling to clinically interpret genetic variants: CACNA1F as an exemplar
Authors: Sallah Shalaw R. , Sergouniotis Panagiotis I. , Barton Stephanie , Ramsden Simon , Taylor Rachel L. , Safadi Amro , Kabir Mitra , Ellingford Jamie M. , Lench Nick , Lovell Simon C. , Black Graeme C. M. 
Published: April 2020

AbstractAdvances in DNA sequencing technologies have revolutionised rare disease diagnostics and have led to a dramatic increase in the volume of available genomic data. A key challenge that needs to be overcome to realise the full potential of these technologies is that of precisely predicting the effect of genetic variants on molecular and organismal phenotypes. Notably, despite recent progress, there is still a lack of robust in silico tools that accurately assign clinical significance to variants. Genetic alterations in theCACNA1Fgene are the commonest cause of X-linked incomplete Congenital Stationary Night Blindness (iCSNB), a condition associated with non-progressive visual impairment. We combined genetic and homology modelling data to produce CACNA1F-vp, an in silico model that differentiates disease-implicated from benign missenseCACNA1Fchanges. CACNA1F-vp predicts variant effects on the structure of theCACNA1Fencoded protein (a calcium channel) using parameters based upon changes in amino acid properties; these include size, charge, hydrophobicity, and position. The model produces an overall score for each variant that can be used to predict its pathogenicity. CACNA1F-vp outperformed four other tools in identifying disease-implicated variants (area under receiver operating characteristic and precision recall curves = 0.84; Matthews correlation coefficient = 0.52) using a tenfold cross-validation technique. We consider this protein-specific model to be a robust stand-alone diagnostic classifier that could be replicated in other proteins and could enable precise and timely diagnosis.
Muscle overexpression of Klf15 via an AAV8-Spc5-12 construct does not provide benefits in spinal muscular atrophy mice
Authors: Ahlskog Nina , Hayler Daniel , Krueger Anja , Kubinski Sabrina , Claus Peter , Hammond Suzan M. , Wood Matthew J. A. , Yáñez-Muñoz Rafael J. , Bowerman Melissa 
Published: April 2020

AbstractSpinal muscular atrophy (SMA) is a neuromuscular disease caused by loss of the survival motor neuron (SMN) gene. While there are currently two approved gene-based therapies for SMA, availability, high cost, and differences in patient response indicate that alternative treatment options are needed. Optimal therapeutic strategies will likely be a combination of SMN-dependent and -independent treatments aimed at alleviating symptoms in the central nervous system and peripheral muscles. Krüppel-like factor 15 (KLF15) is a transcription factor that regulates key metabolic and ergogenic pathways in muscle. We have recently reported significant downregulation of Klf15 in muscle of presymptomatic SMA mice. Importantly, perinatal upregulation of Klf15 via transgenic and pharmacological methods resulted in improved disease phenotypes in SMA mice, including weight and survival. In the current study, we designed an adeno-associated virus serotype 8 (AAV8) vector to overexpress a codon-optimized Klf15 cDNA under the muscle-specific Spc5-12 promoter (AAV8-Klf15). Administration of AAV8-Klf15 to severe Taiwanese Smn−/−;SMN2 or intermediate Smn2B/− SMA mice significantly increased Klf15 expression in muscle. We also observed significant activity of the AAV8-Klf15 vector in liver and heart. AAV8-mediated Klf15 overexpression moderately improved survival in the Smn2B/− model but not in the Taiwanese mice. An inability to specifically induce Klf15 expression at physiological levels in a time- and tissue-dependent manner may have contributed to this limited efficacy. Thus, our work demonstrates that an AAV8-Spc5-12 vector induces high gene expression as early as P2 in several tissues including muscle, heart, and liver, but highlights the challenges of achieving meaningful vector-mediated transgene expression of Klf15.