bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multi-octave-spanning supercontinuum generation through high-energy laser filaments in YAG and ZnSe pumped by a 2.4 μm femtosecond Cr:ZnSe laser
Authors: Nam Sang-Hoon , Nagar Garima C. , Dempsey Dennis , Novák Ondřej , Shim Bonggu , Hong Kyung-Han 
Published: March 2021

Abstract
We present experimental and numerical investigations of high-energy mid-infrared filamentation with multi-octave-spanning supercontinuum generation (SCG), pumped by a 2.4 μm, 250 fs Cr:ZnSe chirped-pulse laser amplifier. The SCG is demonstrated in both anomalous and normal dispersion regimes with YAG and polycrystalline ZnSe, respectively. The formation of stable and robust single filaments along with the visible-to-mid-infrared SCG is obtained with a pump energy of up to 100 μJ in a 6-mm-long YAG medium. To the best of the authors’ knowledge, this is the highest-energy multi-octave-spanning SCG from a laser filament in a solid. On the other hand, the SCG and even-harmonic generation based on random quasi-phase matching (RQPM) are simultaneously observed from the single filaments in a 6-mm-long polycrystalline ZnSe medium with a pump energy of up to 15 μJ. The numerical simulations based on unidirectional pulse propagation equation and RQPM show excellent agreement with the measured multi-octave-spanning SCG and even-harmonic generation. They also reveal the temporal structure of mid-infrared filaments, such as soliton-like self-compression in YAG and pulse broadening in ZnSe.
Pipeline or Pipedream: Gender Balance Legislation’s Effect on Women’s Presence in State Government
Authors: McQueen Shannon 
Published: March 2021

AbstractCan legislation encouraging women’s political involvement impact women’s desire to run for elected office? Eleven states have passed legislation to promote equal gender representation on appointed government boards, and many argue this legislation will also develop a pipeline of women candidates to run for elected office. This paper is the first scholarly work to assess if gender balance legislation (GBL) increases the number of women candidates and women legislators within a state. I use a nonparametric generalization of the difference-in-differences estimator and find very little evidence that GBL significantly impacts women’s representation at the state level. Results are consistent across multiple outcome variables and different model specifications, including two-way fixed effects, generalized synthetic control, and synthetic control models. The insignificant impact of GBL speaks to the need to thoroughly investigate which institutional reforms adequately feed the female candidate pipeline.
Arctic Ocean Freshwater in CMIP6 Ensembles: Declining Sea Ice, Increasing Ocean Storage and Export
Authors: Zanowski Hannah , Jahn Alexandra , Holland Marika M. 
Published: March 2021

AbstractThe Arctic has undergone dramatic changes in sea ice cover and the hydrologic cycle, both of which strongly impact the freshwater storage in, and export from, the Arctic Ocean. Here we analyze Arctic freshwater storage and fluxes in seven climate models from the Coupled Model Intercomparison Project Phase 6 (CMIP6) and assess their performance over the historical period (1980–2000) and in two future emissions scenarios, SSP1‐2.6 and SSP5‐8.5. Similar to CMIP5, substantial differences exist between the models' Arctic mean states and the magnitude of their 21st century storage and flux changes. In the historical simulation, most models disagree with observations over 1980–2000. In both future scenarios, the models show an increase in liquid freshwater storage and a reduction in solid storage and fluxes through the major Arctic gateways (Bering Strait, Fram Strait, Davis Strait, and the Barents Sea Opening) that is typically larger for SSP5‐8.5 than SSP1‐2.6. The liquid fluxes are driven by both volume and salinity changes, with models exhibiting a change in sign (relative to 1980–2000) of the freshwater flux through the Barents Sea Opening by mid‐century, little change in the Bering Strait flux, and increased export from the remaining straits by the end of the 21st century. In the straits west of Greenland (Nares, Barrow, and Davis straits), the models disagree on the behavior of the liquid freshwater export in the early‐to‐mid 21st century due to differences in the magnitude and timing of a simulated decrease in the volume flux.
Global Modeled Sinking Characteristics of Biofouled Microplastic
Authors: Lobelle Delphine , Kooi Merel , Koelmans Albert A. , Laufkötter Charlotte , Jongedijk Cleo E. , Kehl Christian , van Sebille Erik 
Published: March 2021

AbstractMicroplastic debris ending up at the sea surface has become a known major environmental issue. However, how microplastic particles move and when they sink in the ocean remains largely unknown. Here, we model microplastic subject to biofouling (algal growth on a substrate) to estimate sinking timescales and the time to reach the depth where particles stop sinking. We combine NEMO‐MEDUSA 2.0 output, that represents hydrodynamic and biological properties of seawater, with a particle‐tracking framework. Different sizes and densities of particles (for different types of plastic) are simulated, showing that the global distribution of sinking timescales is largely size‐dependent as opposed to density‐dependent. The smallest particles we simulate (0.1 μm) start sinking almost immediately around the globe and their trajectories take the longest time to reach their first sinking depth (relative to larger particles). In oligotrophic subtropical gyres with low algal concentrations, particles between 1 and 0.01 mm do not sink within the simulation time of 90 days. This suggests that in addition to the comparatively well‐known physical processes, biological processes might also contribute to the accumulation of floating plastic (of 1–0.01 mm) in subtropical gyres. Particles of 1 μm in the gyres start sinking largely due to vertical advection, whereas in the equatorial Pacific they are more dependent on biofouling. The qualitative impacts of seasonality on sinking timescales are small, however, localized sooner sinking due to spring algal blooms is seen. This study maps processes that affect the sinking of virtual microplastic globally, which could ultimately impact the ocean plastic budget.
The Dependence of Ship‐Polluted Marine Cloud Properties and Radiative Forcing on Background Drop Concentrations
Authors: Hu Shuang , Zhu Yannian , Rosenfeld Daniel , Mao Feiyue , Lu Xin , Pan Zengxin , Zang Lin , Gong Wei 
Published: March 2021

AbstractMarine low clouds of the busy shipping lane in the southeast Atlantic during the springs of 2003–2015 were analyzed to study the dependence of their properties and radiative forcing on the background cloud drop concentrations (Nd‐bg). The overall average cloud radiative effect within the shipping lane was larger by only −1 Wm−2 compared to the adjacent clouds. However, this near‐zero averaged effect was composed of large negative cloud radiative forcing (CRF) for the cleanest (13%) of the cases with Nd‐bg < 50 cm−3, which was almost neutralized by a positive CRF for the 40% of the cases with Nd‐bg > 70 cm−3. A possible explanation for this positive forcing is the cloud burning effect of the black carbon from ship emissions. The negative forcing was composed of 45% for the cloud fraction (Cf) effect and 55% for the albedo effects, which included a small contribution of the liquid water path (LWP) effect. Positive Cf susceptibility to Nd‐core was at maximum for the lowest Nd‐bg and disappeared near 60 cm−3. The albedo susceptibility to Nd‐core reached its theoretical limit of 1/3 for constant LWP when Nd‐bg <40 cm−3, and diminishes to 0.2 when Nd‐bg = 60 cm−3. These susceptibilities represent cause and effect relationships because the differences of aerosols caused by the ship emissions vary at a much smaller scale than meteorology. Globally, under similar environmental conditions, nearly half of the area has Nd < 50 cm−3, thus possessing the indicated large susceptibility of negative radiative forcing to anthropogenic aerosols.
Improved Global Maps of the Optimum Growth Temperature, Maximum Light Use Efficiency, and Gross Primary Production for Vegetation
Authors: Chen Yongzhe , Feng Xiaoming , Fu Bojie , Wu Xutong , Gao Zhen 
Published: March 2021

AbstractThe optimum growth temperature (Topt) and maximum light use efficiency (εmax) of terrestrial vegetation are closely related to plant photosynthesis in current and future Earth environments, yet little is known about their spatial distributions at the global scale. This study derived global maps of Topt and εmax separately, under the light use efficiency (LUE) model framework by utilizing FLUXNET measurements and satellite‐observed solar/sun‐induced chlorophyll fluorescence (SIF), as well as multiple regression and neural network regression based on environmental and biological factors. Topt is found to be positively correlated with annual mean temperature (T), except in cold areas with T < 9°C, where Topt stays within the range of 10°C–15°C. Topt is equal to T in tropical areas with T ≥ 25°C, but is obviously higher than T in other regions. εmax is high in regions with a large amount of diffuse radiation and increases significantly with water stress. The maps of Topt and εmax improved the global gross primary production (GPP) estimation (R2 = 0.83, RMSE = 1.38 g C m−2 d−1 against flux observations). The average annual GPP was 126 ± 1.5 PgC yr−1, with a trend of 0.6 ± 0.1 PgC yr−2 during 2001–2016, faster than most previous estimates. Our study suggests that the positive anthropogenic impacts on GPP were underestimated in existing products, including cropland expansion in southern Brazil and afforestation/forest protection efforts in China and western Europe. This study also provides a potential method for unified GPP modeling under the LUE framework.
The Case for Tectonic Control on Erosional Exhumation on the Tropical Northern Andes Based on Thermochronology Data
Authors: Pérez‐Consuegra N. , Hoke G. D. , Mora A. , Fitzgerald P. , Sobel E. R. , Sandoval J. R. , Glodny J. , Valencia V. , Parra M. , Zapata S. 
Published: March 2021

AbstractThe tropical Northern Andes constitutes a great area to explore the interaction of tectonics and climate on the evolution of orogenic topography, as they are tectonically active, have steep gradients in relief and precipitation, and were less affected by Quaternary glaciations than high‐latitude mountains. This study combines new and published thermochronology along ∼500 km of the Eastern Cordillera in Colombia to explore what controls the rates of Miocene and Pliocene exhumation, including: (1) variations in late Cenozoic paleoclimate, (2) orographic precipitation or (3) variation in rock uplift associated with structural heterogeneities along the eastern flank of the range. New thermochronology data consists of 27 apatite and seven zircon (U‐Th)/He ages and five apatite fission track ages. Thermal history models show that rock cooling as a result of erosional exhumation has occurred everywhere in the Eastern Cordillera since at least the Miocene at spatially and temporally variable rates. Exhumation rates vary by an order of magnitude between various fault‐bounded blocks and there is no evidence for a spatially uniform increase in exhumation rates during the past ∼4–5 Ma that would indicate uniform climatic driven exhumation. The west (dry) to east (wet) gradient in precipitation rates across the Garzon Massif is not a major factor controlling the exhumation rates, as the exhumation rates are highest on the western drier flank. The greatest rates of exhumation of the Eastern Cordillera occur in the blocks associated with vigorous Cenozoic reactivation of inherited faults that had focused extension during Early Cretaceous rifting.
Measuring and Interpreting Multilayer Aquifer‐System Compactions for a Sustainable Groundwater‐System Development
Authors: Hung Wei‐Chia , Hwang Cheinway , Sneed Michelle , Chen Yi‐An , Chu Chi‐Hua , Lin Shao‐Hung 
Published: March 2021

AbstractEver decreasing water resources and climate change have driven the increasing use of groundwater causing land subsidence in many countries. Geodetic sensors such as InSAR, GPS and leveling can detect surface deformation but cannot measure subsurface deformation. A single‐well, single‐depth extensometer can be used to measure subsurface deformation, but it cannot delineate the depths of major compaction and provide insight about the deformation mechanism throughout a complex aquifer system, unless man extensometers at different depths are used. We present a multilayer compaction well (MLCW), installed in a borehole, that uses magnetic rings to detect stratum compaction at 25 depths as deep as 300 m below land surface. Our laboratory and field assessments indicate 1 mm precision and accuracy for one single‐depth magnetic reading. We tested the performance of MLCW by measuring aquifer‐system compaction over the proximal, middle, and distal fans of the Choushui River Alluvial Fan (CRAF) that has long experienced severe land subsidence. The MLCW measurements were used to create time‐depth diagrams of compaction, showing different compaction rates at different layers of aquifers and aquitards to identify the depths of major compactions. The elastic (reversible) and inelastic (irreversible) compactions from MLCW were used in stress‐strain analyses to estimate skeletal specific storages and the safe groundwater levels, below which groundwater extractions have caused irreversible compactions. The hydrogeological parameters derived from MLCW measurements can help governmental agencies to determine effective land‐use and water‐use policies, and ascertain the best strategy for utilizing artificial recharge to prevent land subsidence and achieve sustainable groundwater management.
Extreme heat events heighten soil respiration
Authors: Anjileli Hassan , Huning Laurie S. , Moftakhari Hamed , Ashraf Samaneh , Asanjan Ata Akbari , Norouzi Hamid , AghaKouchak Amir 
Published: March 2021

AbstractIn the wake of climate change, extreme events such as heatwaves are considered to be key players in the terrestrial biosphere. In the past decades, the frequency and severity of heatwaves have risen substantially, and they are projected to continue to intensify in the future. One key question is therefore: how do changes in extreme heatwaves affect the carbon cycle? Although soil respiration (Rs) is the second largest contributor to the carbon cycle, the impacts of heatwaves on Rs have not been fully understood. Using a unique set of continuous high frequency in-situ measurements from our field site, we characterize the relationship between Rs and heatwaves. We further compare the Rs response to heatwaves across ten additional sites spanning the contiguous United States (CONUS). Applying a probabilistic framework, we conclude that during heatwaves Rs rates increase significantly, on average, by ~ 26% relative to that of non-heatwave conditions over the CONUS. Since previous in-situ observations have not measured the Rs response to heatwaves (e.g., rate, amount) at the high frequency that we present here, the terrestrial feedback to the carbon cycle may be underestimated without capturing these high frequency extreme heatwave events.
Long-term evolution of the epithelial cell secretome in preclinical 3D models of the human bronchial epithelium
Authors: Sanchez-Guzman Daniel , Boland Sonja , Brookes Oliver , Mc Cord Claire , Lai Kuen René , Sirri Valentina , Baeza Squiban Armelle , Devineau Stéphanie 
Published: March 2021

AbstractThe human bronchial epithelium is the first line of defense against atmospheric particles, pollutants, and respiratory pathogens such as the novel SARS-CoV-2. The epithelial cells form a tight barrier and secrete proteins that are major components of the mucosal immune response. Functional in vitro models of the human lung are essential for screening the epithelial response and assessing the toxicity and barrier crossing of drugs, inhaled particles, and pollutants. However, there is a lack of models to investigate the effect of chronic exposure without resorting to animal testing. Here, we developed a 3D model of the human bronchial epithelium using Calu-3 cell line and demonstrated its viability and functionality for 21 days without subculturing. We investigated the effect of reduced Fetal Bovine Serum supplementation in the basal medium and defined the minimal supplementation needed to maintain a functional epithelium, so that the amount of exogenous serum proteins could be reduced during drug testing. The long-term evolution of the epithelial cell secretome was fully characterized by quantitative mass spectrometry in two preclinical models using Calu-3 or primary NHBE cells. 408 common secreted proteins were identified while significant differences in protein abundance were observed with time, suggesting that 7–10 days are necessary to establish a mature secretome in the Calu-3 model. The associated Reactome pathways highlight the role of the secreted proteins in the immune response of the bronchial epithelium. We suggest this preclinical 3D model can be used to evaluate the long-term toxicity of drugs or particles on the human bronchial epithelium, and subsequently to investigate their effect on the epithelial cell secretions.
Low-dose aspirin was associated with an increased risk of cardiovascular events in patients with chronic kidney disease and low bodyweight: results from KNOW-CKD study
Authors: Oh Yun Jung , Kim Ae Jin , Ro Han , Chang Jae Hyun , Lee Hyun Hee , Chung Wookyung , Hyun Young Youl , Lee Joongyub , Kim Yeong Hoon , Han Seung Hyeok , Chae Dong-Wan , Ahn Curie , Oh Kook-Hwan , Jung Ji Yong 
Published: March 2021

AbstractThe benefits and risks of aspirin therapy for patients with chronic kidney disease (CKD) who have a high burden of cardiovascular events (CVE) are controversial. To examine the effects of low-dose aspirin on major clinical outcomes in patients with CKD. As a prospective observational cohort study, using propensity score matching, 531 aspirin recipients and non-recipients were paired for analysis from 2070 patients and fulfilled the inclusion criteria among 2238 patients with CKD. The primary outcome was the first occurrence of major CVE. The secondary outcomes were kidney events defined as a > 50% reduction of estimated glomerular filtration rate from baseline, doubling of serum creatinine, or onset of kidney failure with replacement therapy, the all-cause mortality, and bleeding event. The incidence of CVE was significantly greater in low-dose aspirin users than in non-users (HR 1.798;P = 0.011). A significant association between aspirin use and an increased risk of CVE was observed only in the lowest quartile of body weight (HR 4.014;P = 0.019) (Q1 < 60.0 kg). Secondary outcomes were not significantly different between aspirin users and non-users. It needs to be individualized of prescribing low-dose aspirin for the prevention of cardiovascular events in patients with chronic kidney disease, particularly patients with low bodyweight (< 60 kg).
Scalable nanoprecipitation of niclosamide andin vivodemonstration of long-acting delivery after intramuscular injection
Authors: Hobson James J. , Savage Alison C. , Dwyer Andrew B. , Unsworth Catherine , Massam Jonathan , Arshad Usman , Pertinez Henry , Box Helen , Tatham Lee , Rajoli Rajith K. R. , Neary Megan , Sharp Joanne , Valentijn Anthony , David Christopher , Curley Paul , Liptrott Neill J. , McDonald Tom O. , Owen Andrew , Rannard Steve P. 
Published: March 2021

Controlling COVID-19 requires therapy and continued vaccination. Long-acting therapeutics offer options for test-and-cure strategies and overcome poor therapy adherence. Extended in vivo niclosamide exposure is demonstrated here as such a candidate.
Performance analysis of dual‐function multiple‐input multiple‐output radar‐communications using frequency hopping waveforms and phase shift keying signalling
Authors: Eedara Indu Priya , Hassanien Aboulnasr , Amin Moeness G. 
Published: March 2021

AbstractA signal embedding scheme into the emission of multiple‐input multiple‐output (MIMO) frequency hopping (FH) radar is analysed. In this scheme, the phase shift keying (PSK) communication symbols are multiplied with the frequency hops in fast‐time, resulting in dual‐function radar‐communication (DFRC) waveforms. The authors examine the impact of PSK symbol embedding on the ambiguity function (AF) and power spectral density (PSD) and show that modulation of the radar pulse can benefit the radar functionality. The effect of PSK symbol embedding on the radar target detection performance of the DFRC system is delineated. The authors’ analyses show that the use of the DFRC waveforms enhances target detection performance. The authors also provide the symbol error rates (SERs) corresponding to different phase constellations at the communication receiver and address the practical data transfer rates that can be achieved with the underlying embedding scheme.
Robust estimation of the number of coherent radar signal sources using deep learning
Authors: Rogers John , Ball John E. , Gurbuz Ali C. 
Published: March 2021

AbstractA deep‐learning‐based approach to estimating the number of coherent sources in radar is presented. A proper estimate of the number of sources in a signal enables improved angle‐of‐arrival (AoA) estimation common in applications such as radar, sonar, and communication systems. Many AoA estimators utilised in these areas require accurate estimates of the number of sources for enhanced performance. Herein, a robust method that performs well under the existence of coherent sources is developed. The proposed method is based on deep learning and it is shown to perform better than state‐of‐the‐art versions of the Akaike Information Criteria (AIC), Minimum Description Length (MDL), and Exponentially Embedded Families (EEF) estimators, which employ spatial smoothing of the covariance matrix to handle coherent signals.
A hybrid robust‐stochastic approach for optimal scheduling of interconnected hydrogen‐based energy hubs
Authors: Mansour‐Satloo Amin , Agabalaye‐Rahvar Masoud , Mirazaei Mohammad Amin , Mohammadi‐Ivatloo Behnam , Zare Kazem , Anvari‐Moghaddam Amjad 
Published: March 2021

AbstractThe energy hub (EH) concept is an efficient way to integrate various energy carriers. In addition, demand response programmes (DRPs) are complementary to improving an EH's efficiency and increase energy system flexibility. The hydrogen storage system, as a green energy carrier, has an essential role in balancing supply and demand precisely, similar to other storage systems. A hybrid robust‐stochastic approach is applied herein to address fluctuations in wind power generation, multiple demands, and electricity market price in a hydrogen‐based smart micro‐energy hub (SMEH) with multi‐energy storage systems. The proposed hybrid approach enables the operator to manage the existing uncertainties with more flexibility. Also, flexible electrical and thermal demands under an integrated demand response programme (IDRP) are implemented in the proposed SMEH. The optimal scheduling of the hydrogen‐based SMEH problem considering wind power generation and electricity market price fluctuations, as well as IDRP, is modelled via a mixed‐integer linear programming problem. Finally, the validity and applicability of the proposed model are verified through simulation and numerical results.