bluuebunny/crossref_metadata_2025_split huggingface dataset:
Energized Oxygen in the Magnetotail: Onset and Evolution of Magnetic Reconnection
Authors: George Don E , Jahn Jörg‐Micha 
Published: September 2022

AbstractOxygen ions are a major constituent of magnetospheric plasma, yet the role of oxygen in processes such as magnetic reconnection continues to be poorly understood. Observations show that significant amounts of energized O+ can be present in a magnetotail current sheet (CS). A population of thermal O+ only has a relatively minor effect on magnetic reconnection. Despite this, published studies have so far only concentrated on the role of the low‐energy thermal O+. We present a study of magnetic reconnection in a thinning CS with energized O+ present. Well‐established, three‐species, 2.5D particle‐in‐cell (PIC) kinetic simulations are used. Simulations of thermal H+ and thermal O+ validate our setup against published results. We then energize a thermal background O+ based on published in situ measurements. A range of energization is applied to the background O+. We discuss the effects of energized O+ on CS thinning and the onset and evolution of magnetic reconnection. The presence of energized O+ causes a two‐regime onset response in a thinning CS. As energization increases in the lower‐regime, reconnection develops at a single primary X‐line, increases time‐to‐onset, and suppresses the rate of evolution. As energization continues to increase in the higher‐regime, reconnection develops at multiple X‐lines, forming a stochastic plasmoid chain; decreases time‐to‐onset; and enhances evolution via a plasmoid instability. Energized O+ drives a depletion of the background H+ around the central CS. As the energization increases, the CS thinning begins to slow and eventually reverses.
Flash Droughts Identification Based on an Improved Framework and Their Contrasting Impacts on Vegetation Over the Loess Plateau, China
Authors: Zheng Xudong , Huang Shengzhi , Peng Jian , Leng Guoyong , Huang Qiang , Fang Wei , Guo Yi 
Published: September 2022

AbstractFlash drought occurs in a short timescale and has more adverse impacts on society and ecosystems than regular drought. Considering flash drought as a special type of regular drought and identifying it by the rate of the first intensification period might ignore posterior intensification periods. To this end, we introduced the combinatorial decomposable flash drought identification framework (CDFDI) to identify flash drought from the perspective of regarding it as the subphase of drought and explore the characteristics and vegetation response of flash drought in the Loess Plateau (LP), China, where is prone to drought and its ecological environment is very fragile. The neffectiveness of the framework is evaluated through the comparison analysis with a preexisting identification method proposed by Li et al. (2020, https://doi.org/10.5194/essd-12-1217-2020). Results indicate that: (a) the CDFDI framework can better capture flash drought events than the Liu's method in terms of time series and spatial patterns, its rationality was further demonstrated by the obvious latitudinal pattern of correlation between flash drought and normalized difference vegetation index (NDVI); (b) the correlation shows an southeast (positive) and northwest (negative) contrasting pattern in the LP; (c) such contrasting pattern was also found in the response time of GPP, which suggests a more rapid impact on vegetation of flash drought in the arid northwestern LP; and (d) flash drought shows an exacerbating trend across the LP under the background of climate warming and mainly concentrated in the southern part. In general, this study provides new insights on flash drought connotations in a changing environment.
Global and Regional Drivers of Power Plant CO2Emissions Over the Last Three Decades Revealed From Unit‐Based Database
Authors: Qin Xinying , Tong Dan , Liu Fei , Wu Ruili , Zheng Bo , Zheng Yixuan , Liu Jun , Xu Ruochong , Chen Cuihong , Yan Liu , Zhang Qiang 
Published: September 2022

AbstractThe past three decades have witnessed the dramatic expansion of global biomass‐ and fossil fuel‐fired power plants, but the tremendously diverse power infrastructure shapes different spatial and temporal CO2emission characteristics. Here, by combining Global Power plant Emissions Database (GPED v1.1) constructed in this study and the previously developed China coal‐fired power Plant Emissions Database (CPED), we analyzed multi‐scale changes and underlying drivers from the globe to the unit in generating capacities, age structure, and CO2emissions over the past 30 yr. Our estimates show global CO2emissions from the power sector increased from 7.5 Gt in 1990 to 13.9 Gt in 2019, and the growth of power demand meeting by large and young units mainly drives this increase for all stages. However, regional drivers were broadly different from those affecting global trends. For example, the critical roles of thermal efficiency improvement (accounting for 20% of the decrease in CO2emissions) by eliminating small and low‐efficient coal‐fired units and fossil fuel mix (61%) by developing natural‐gas‐ and oil‐fired units were identified in preventing CO2emission increases in the developed regions. By contrast, the decrease of fossil fuel share by speeding up the expansion of renewable power gradually demonstrates its importance in curbing emissions in the most of regions, especially including the developing economies (i.e., China and India) after 2010. Our multi‐scale results of 30 yr emission variations indicate the structure optimization and transformations of power plants is paramount importance to further curb or reduce CO2emissions from the power sector.
Estimating the Likelihood of GHG Concentration Scenarios From Probabilistic Integrated Assessment Model Simulations
Authors: Huard David , Fyke Jeremy , Capellán‐Pérez Iñigo , Matthews H. Damon , Partanen Antti‐Ilari 
Published: September 2022

AbstractThe climate scenarios that form the basis for current climate risk assessments have no assigned probabilities, and this impedes the analysis of future climate risks. This paper proposes an approach to estimate the probability of carbon dioxide (CO2) concentration scenarios used in key climate change modeling experiments. It computes the CO2 emissions compatible with the concentrations prescribed by Coupled Model Intercomparison Project Phase 5 (CMIP5) and CMIP6 experiments. The distribution of these compatible cumulative emissions is interpreted as the likelihood of future emissions given a concentration pathway. Using Bayesian analysis, the probability of each pathway can be estimated from a probabilistic sample of future emissions. The approach is demonstrated with five probabilistic CO2 emission simulation ensembles from four Integrated Assessment Models (IAM), leading to independent estimates of the likelihood of the CO2 concentration of Representative Concentration Pathways (RCP) and Shared Socioeconomic Pathways (SSP). Results suggest that SSP5‐8.5 is unlikely for the second half of the 21st century, but offer no clear consensus on which of the remaining scenarios is most likely. Estimates of likelihoods of CO2 concentrations associated with RCP and SSP scenarios are affected by sampling errors, differences in emission sources simulated by the IAMs, and a lack of a common experimental framework for IAM simulations. These shortcomings, along with a small IAM ensemble size, limit the applicability of the results presented here. Novel joint IAM and the Earth System Model experiments are needed to deliver actionable probabilistic climate risk assessments.
L‐Value and Energy Dependence of 0.1–50 keV O+, He+, and H+ Ions for CME and CIR Storms Over the Entire Van Allen Probes Era
Authors: Pandya Megha , Bhaskara Veenadhari , Ebihara Yusuke , Reeves G. D. 
Published: September 2022

AbstractOur studies report the first observation of L‐value and energy sorted correlation of differential fluxes of 0.1–50 keV O+, He+, and H+ ions with different geophysical parameters for 29 Coronal Mass Ejected (CME) and 40 Corotating Interaction Region (CIR)‐driven geomagnetic storms during the entire Van Allen Probes era. For both solar wind drivers, ions with ≥1 keV energies show more variability in response to the solar wind changes, while the lower energy (<1 keV) ions are relatively stable. During the in‐storm interval, O+ ions show maximum flux enhancement and become further prominent during CME storms. O+ ion (≥10 keV) fluxes show good correlation with − VswBz, and Sym‐H index during CME‐driven storms in the L ∼2.5–5.5. Apart from this, the average duration of persistence (〈Δt〉) for enhanced fluxes is higher for CIR‐driven storms with >> at E ≤ 50 keV in the L ∼2.5–5.5. Moreover, the observed value of 〈Δt〉i (where i is O+, H+ or He+) increases with the increasing L. We discuss the plausible mechanisms to provide a comprehensive overview of L‐values and energy sorted O+, He+ and H+ ion dynamics for two different categories of solar wind drivers.
NRLMSIS 2.1: An Empirical Model of Nitric Oxide Incorporated Into MSIS
Authors: Emmert J. T. , Jones M. , Siskind D. E. , Drob D. P. , Picone J. M. , Stevens M. H. , Bailey S. M. , Bender S. , Bernath P. F. , Funke B. , Hervig M. E. , Pérot K. 
Published: September 2022

AbstractWe have developed an empirical model of nitric oxide (NO) number density at altitudes from ∼73 km to the exobase, as a function of altitude, latitude, day of year, solar zenith angle, solar activity, and geomagnetic activity. The model is part of the NRLMSIS® 2.1 empirical model of atmospheric temperature and species densities; this upgrade to NRLMSIS 2.0 consists solely of the addition of NO. MSIS 2.1 assimilates observations from six space‐based instruments: UARS/HALOE, SNOE, Envisat/MIPAS, ACE/FTS, Odin/SMR, and AIM/SOFIE. We additionally evaluated the new model against independent extant NO data sets. In this paper, we describe the formulation and fitting of the model, examine biases between the data sets and model and among the data sets, compare with another empirical NO model (NOEM), and discuss scientific aspects of our analysis.
Nitrogen Sinks or Sources? Denitrification and Nitrogen Removal Potential in Riparian Legacy Sediment Terraces Affected by Milldams
Authors: Peck Erin. K. , Inamdar Shreeram , Sherman Melissa , Hripto Johanna , Peipoch Marc , Gold Arthur J. , Addy Kelly 
Published: September 2022

AbstractRiparian zones are key ecotones that buffer aquatic ecosystems through removal of nitrogen (N) via processes such as denitrification. However, how dams alter riparian N cycling and buffering capacity is poorly understood. Here, we hypothesized that elevated groundwater and anoxia due to the backup of stream water above milldams may enhance denitrification. We assessed denitrification rates (using denitrification enzyme assays) and potential controlling factors in riparian sediments at various depths upstream and downstream of two relict U.S. mid‐Atlantic milldams. Denitrification was not significantly different between upstream and downstream, although was greater per river km upstream considering deeper and wider geometries. Further, denitrification typically occurred in hydrologically variable shallow sediments where nitrate‐N and organic matter were most concentrated. At depths below 1 m, both denitrification and nitrate‐N decreased while ammonium‐N concentrations substantially increased, indicating suppression of ammonium consumption or dissimilatory nitrate reduction to ammonium. These results suggest that denitrification occurs where dynamic groundwater levels result in higher rates of nitrification and mineralization, while another N process that produces ammonium‐N competes with denitrification for limited nitrate‐N at deeper, more stagnant/poorly mixed depths. Ultimately, while it is unclear whether relict milldams are sources of N, limited denitrification rates indicate that they are not always effective sinks; thus, milldam removal—especially accompanied by removal of ammonium‐N rich legacy sediments—may improve riparian N buffering.
CME Evolution in the Structured Heliosphere and Effects at Earth and Mars During Solar Minimum
Authors: Palmerio Erika , Lee Christina O. , Richardson Ian G. , Nieves‐Chinchilla Teresa , Dos Santos Luiz F. G. , Gruesbeck Jacob R. , Nitta Nariaki V. , Mays M. Leila , Halekas Jasper S. , Zeitlin Cary , Xu Shaosui , Holmström Mats , Futaana Yoshifumi , Mulligan Tamitha , Lynch Benjamin J. , Luhmann Janet G. 
Published: September 2022

AbstractThe activity of the Sun alternates between a solar minimum and a solar maximum, the former corresponding to a period of “quieter” status of the heliosphere. During solar minimum, it is in principle more straightforward to follow eruptive events and solar wind structures from their birth at the Sun throughout their interplanetary journey. In this paper, we report analysis of the origin, evolution, and heliospheric impact of a series of solar transient events that took place during the second half of August 2018, that is, in the midst of the late declining phase of Solar Cycle 24. In particular, we focus on two successive coronal mass ejections (CMEs) and a following high‐speed stream (HSS) on their way toward Earth and Mars. We find that the first CME impacted both planets, whilst the second caused a strong magnetic storm at Earth and went on to miss Mars, which nevertheless experienced space weather effects from the stream interacting region preceding the HSS. Analysis of remote‐sensing and in‐situ data supported by heliospheric modeling suggests that CME–HSS interaction resulted in the second CME rotating and deflecting in interplanetary space, highlighting that accurately reproducing the ambient solar wind is crucial even during “simpler” solar minimum periods. Lastly, we discuss the upstream solar wind conditions and transient structures responsible for driving space weather effects at Earth and Mars.
Moderate and Severe Hydrological Droughts in Europe Differ in Their Hydrometeorological Drivers
Authors: Brunner Manuela I. , Van Loon Anne F. , Stahl Kerstin 
Published: September 2022

AbstractHydrological extreme events are generated by different sequences of hydrometeorological drivers, the importance of which may vary within the sample of drought events. Here, we investigate how the importance of different hydrometeorological driver sequences varies by event magnitude using a large sample of catchments in Europe. To do so, we develop an automated classification scheme for streamflow drought events. The classification scheme standardizes a previous qualitative drought typology and assigns events to one of eight drought event types—each characterized by a set of single or compounding drivers—using information about seasonality, precipitation deficits, and snow availability. The objective event classification reveals how drought drivers vary not just in space and by season, but also with event magnitude. Specifically, we show that (a) rainfall deficit droughts and cold snow season droughts are the dominant drought event type in Western Europe and Eastern and Northern Europe, respectively; (b) rainfall deficit and cold snow season droughts are important from autumn to spring while snowmelt and wet‐to‐dry season droughts are important in summer; and (c) moderate droughts are mainly driven by rainfall deficits while severe events are mainly driven by snowmelt deficits in colder climates and by streamflow deficits transitioning from the wet to the dry season in warmer climates. These differences in sequences of drought generation mechanisms for severe and moderate events suggest that future changes in hydrometeorological drivers may affect moderate and severe events differently.
The acute effect of glucagon on components of energy balance and glucose homoeostasis in adults without diabetes: a systematic review and meta-analysis
Authors: Frampton James , Izzi-Engbeaya Chioma , Salem Victoria , Murphy Kevin G. , Tan Tricia M. , Chambers Edward S. 
Published: September 2022

Abstract
Objective
Using a systematic review and meta-analysis, we aimed to estimate the mean effect of acute glucagon administration on components of energy balance and glucose homoeostasis in adults without diabetes.

Methods
CENTRAL, CINAHL, Embase, MEDLINE, PubMed, and Scopus databases were searched from inception to May 2021. To be included, papers had to be a randomised, crossover, single- or double-blind study, measuring ad libitum meal energy intake, energy expenditure, subjective appetite, glucose, and/or insulin following acute administration of glucagon and an appropriate comparator in adults without diabetes. Risk of bias was assessed using the Revised Cochrane Risk of Bias Tool for Randomized trials with additional considerations for cross-over trials. Certainty of evidence was assessed using the GRADE approach. Random-effect meta-analyses were performed for outcomes with at least five studies. This study is registered on PROSPERO (CRD42021269623).

Results
In total, 13 papers (15 studies) were considered eligible: energy intake (5 studies, 77 participants); energy expenditure (5 studies, 59 participants); subjective appetite (3 studies, 39 participants); glucose (13 studies, 159 participants); insulin (12 studies, 147 participants). All studies had some concerns with regards to risk of bias. Mean intervention effect of acute glucagon administration on energy intake was small (standardised mean difference [SMD]: –0.19; 95% CI, –0.59 to 0.21; P = 0.345). Mean intervention effect of acute glucagon administration on energy expenditure (SMD: 0.72; 95% CI, 0.37–1.08; P < 0.001), glucose (SMD: 1.11; 95% CI, 0.60–1.62; P < 0.001), and insulin (SMD: 1.33; 95% CI, 0.88–1.77; P < 0.001) was moderate to large.

Conclusions
Acute glucagon administration produces substantial increases in energy expenditure, and in circulating insulin and glucose concentrations. However, the effect of acute glucagon administration on energy intake is unclear. Insufficient evidence was available to evaluate the acute effect of glucagon on subjective appetite.
All-angle reflectionless negative refraction with ideal photonic Weyl metamaterials
Authors: Liu Yachao , Wang Guo Ping , Pendry John B. , Zhang Shuang 
Published: September 2022

AbstractNegative refraction, an unnatural optical phenomenon in which the incident and the refracted waves reside on the same side of the surface normal, has been demonstrated with the invention of negative index media based on artificially engineered photonic structures called metamaterials. It has received wide attention due to its potential applications in imaging, nonlinear optics, and electromagnetic cloaking. However, it is highly challenging to realize negative refraction operating at all angles and with the perfect transmission. In this work, leveraging the recent development in topological photonics, we propose to realize reflectionless negative refraction for all incident angles with a topological metamaterial. The proposed metamaterial possesses two Weyl points of opposite topological charges. By interfacing the metamaterial with a perfect electric conductor (PEC) or a perfect magnetic conductor (PMC), the Fermi arc connecting the two Weyl points can take the form of a half-circle possessing a positive or a negative refractive index. Importantly, due to the topological protection, there is no reflection at the interface between the PEC and PMC covered areas, leading to the observation of all-angle negative refraction without reflection at the boundary. Our work provides a new platform for manipulating the propagation of surface waves, which may find applications in the construction of integrated photonic devices.
Stress induced TDP-43 mobility loss independent of stress granules
Authors: Streit Lisa , Kuhn Timo , Vomhof Thomas , Bopp Verena , Ludolph Albert C. , Weishaupt Jochen H. , Gebhardt J. Christof M. , Michaelis Jens , Danzer Karin M. 
Published: September 2022

AbstractTAR DNA binding protein 43 (TDP-43) is closely related to the pathogenesis of amyotrophic lateral sclerosis (ALS) and translocates to stress granules (SGs). The role of SGs as aggregation-promoting “crucibles” for TDP-43, however, is still under debate. We analyzed TDP-43 mobility and localization under different stress and recovery conditions using live cell single-molecule tracking and super-resolution microscopy. Besides reduced mobility within SGs, a stress induced decrease of TDP-43 mobility in the cytoplasm and the nucleus was observed. Stress removal led to a recovery of TDP-43 mobility, which strongly depended on the stress duration. ‘Stimulated-emission depletion microscopy’ (STED) and ‘tracking and localization microscopy’ (TALM) revealed not only TDP-43 substructures within stress granules but also numerous patches of slow TDP-43 species throughout the cytoplasm. This work provides insights into the aggregation of TDP-43 in living cells and provide evidence suggesting that TDP-43 oligomerization and aggregation takes place in the cytoplasm separate from SGs.
Dominant role of DNA methylation over H3K9me3 for IAP silencing in endoderm
Authors: Wang Zeyang , Fan Rui , Russo Angela , Cernilogar Filippo M. , Nuber Alexander , Schirge Silvia , Shcherbakova Irina , Dzhilyanova Iva , Ugur Enes , Anton Tobias , Richter Lisa , Leonhardt Heinrich , Lickert Heiko , Schotta Gunnar 
Published: September 2022

AbstractSilencing of endogenous retroviruses (ERVs) is largely mediated by repressive chromatin modifications H3K9me3 and DNA methylation. On ERVs, these modifications are mainly deposited by the histone methyltransferase Setdb1 and by the maintenance DNA methyltransferase Dnmt1. Knock-out of either Setdb1 or Dnmt1 leads to ERV de-repression in various cell types. However, it is currently not known if H3K9me3 and DNA methylation depend on each other for ERV silencing. Here we show that conditional knock-out of Setdb1 in mouse embryonic endoderm results in ERV de-repression in visceral endoderm (VE) descendants and does not occur in definitive endoderm (DE). Deletion of Setdb1 in VE progenitors results in loss of H3K9me3 and reduced DNA methylation of Intracisternal A-particle (IAP) elements, consistent with up-regulation of this ERV family. In DE, loss of Setdb1 does not affect H3K9me3 nor DNA methylation, suggesting Setdb1-independent pathways for maintaining these modifications. Importantly, Dnmt1 knock-out results in IAP de-repression in both visceral and definitive endoderm cells, while H3K9me3 is unaltered. Thus, our data suggest a dominant role of DNA methylation over H3K9me3 for IAP silencing in endoderm cells. Our findings suggest that Setdb1-meditated H3K9me3 is not sufficient for IAP silencing, but rather critical for maintaining high DNA methylation.
The effect of carbon fertilization on naturally regenerated and planted US forests
Authors: Davis Eric C. , Sohngen Brent , Lewis David J. 
Published: September 2022

AbstractOver the last half century in the United States, the per-hectare volume of wood in trees has increased, but it is not clear whether this increase has been driven by forest management, forest recovery from past land uses, such as agriculture, or other environmental factors such as elevated carbon dioxide, nitrogen deposition, or climate change. This paper uses empirical analysis to estimate the effect of elevated carbon dioxide on aboveground wood volume in temperate forests of the United States. To accomplish this, we employ matching techniques that allow us to disentangle the effects of elevated carbon dioxide from other environmental factors affecting wood volume and to estimate the effects separately for planted and natural stands. We show that elevated carbon dioxide has had a strong and consistently positive effect on wood volume while other environmental factors yielded a mix of both positive and negative effects. This study, by enabling a better understanding of how elevated carbon dioxide and other anthropogenic factors are influencing forest stocks, can help policymakers and other stakeholders better account for the role of forests in Nationally Determined Contributions and global mitigation pathways to achieve a 1.5 degree Celsius target.