bluuebunny/crossref_metadata_2025 huggingface dataset:
Synergistic lubricating effect of graphene/ionic liquid composite material used as an additive
Authors: Liu Lincong , Zhou Ming , Mo Youtang , Bai Pengpeng , Wei Qilin , Jin Long , You Shengli , Wang Mingyue , Li Liangchuan , Chen Xin , Li Xiao , Tian Yu
Published: November 2020

We prepared a graphene/ionic liquid (G/IL) composite material by the hybridization of G and an IL for use as a lubricating oil additive. The friction coefficient and wear volume of a base oil containing 0.04 wt% of the G/IL composite was reduced by 45% and 90%, respectively. Furthermore, the base oil containing the G/IL composite exhibited better lubricating properties than the base oil containing G, IL, or a mixture of IL and G at the same mass fraction. A synergistic lubrication mechanism was also revealed. The G/IL composite was adsorbed and deposited on the wear surface, forming a more ordered protective film and a unique tribochemical reaction film during rubbing. Therefore, the G/IL composite exhibited the synergistic lubricating effects of G and IL, which significantly improved the lubricating performance of the base oil. This study also suggested a way to limit the out-of-plane puckering of G at the macroscale.
A molecular dynamics study on the tribological behavior of molybdenum disulfide with grain boundary defects during scratching processes
Authors: Wei Boyu , Kong Ning , Zhang Jie , Li Hongbo , Hong Zhenjun , Zhu Hongtao , Zhuang Yuan , Wang Bo
Published: November 2020

The effect of grain boundary (GB) defects on the tribological properties of MoS2 has been investigated by molecular dynamics (MD) simulations. The GB defects-containing MoS2 during scratching process shows a lower critical breaking load than that of indentation process, owing to the combined effect of pushing and interlocking actions between the tip and MoS2 atoms. The wear resistance of MoS2 with GB defects is relevant to the misorientation angle due to the accumulation of long Mo-S bonds around the GBs. Weakening the adhesion strength between the MoS2 and substrate is an efficient way to improve the wear resistance of MoS2 with low-angle GBs.
Dual-Wavelength Photosensitive Nano-in-Micro Scaffold Regulates Innate and Adaptive Immune Responses for Osteogenesis
Authors: Zhao Qin , Shi Miusi , Yin Chengcheng , Zhao Zifan , Zhang Jinglun , Wang Jinyang , Shen Kailun , Zhang Lingling , Tang Hua , Xiao Yin , Zhang Yufeng
Published: November 2020

The immune response of a biomaterial determines its osteoinductive effect. Although the mechanisms by which some immune cells promote regeneration have been revealed, the biomaterial-induced immune response is a dynamic process involving multiple cells. Currently, it is challenging to accurately regulate the innate and adaptive immune responses to promote osteoinduction in biomaterials. Herein, we investigated the roles of macrophages and dendritic cells (DCs) during the osteoinduction of biphasic calcium phosphate (BCP) scaffolds. We found that osteoinductive BCP directed M2 macrophage polarization and inhibited DC maturation, resulting in low T cell response and efficient osteogenesis. Accordingly, a dual-targeting nano-in-micro scaffold (BCP loaded with gold nanocage, BCP-GNC) was designed to regulate the immune responses of macrophages and DCs. Through a dual-wavelength photosensitive switch, BCP-GNC releases interleukin-4 in the early stage of osteoinduction to target M2 macrophages and then releases dexamethasone in the later stage to target immature DCs, creating a desirable inflammatory environment for osteogenesis. This study demonstrates that biomaterials developed to have specific regulatory capacities for immune cells can be used to control the early inflammatory responses of implanted materials and induce osteogenesis.
Recent advances in the construction of nanozyme-based logic gates
Authors: Pu Fang , Ren Jinsong , Qu Xiaogang
Published: November 2020

Nanozymes, nanomaterials with enzyme-like activity, have been considered as promising alternatives of natural enzymes. Molecular logic gates, which can simulate the function of the basic unit of an electronic computer, perform Boolean logic operation in response to chemical, biological, or optical signals. Recently, the combination of nanozymes and logic gates enabled bioinformation processing in a logically controllable way. In the review, recent progress in the construction of nanozyme-based logic gates integrated with their utility in sensing is introduced. Furthermore, the issues and challenges in the construction processes are discussed. It is expected the review will facilitate a comprehensive understanding of nanozyme-based logic systems.
Peaks of Fine Particulate Matter May Modulate the Spreading and Virulence of COVID-19
Authors: Rohrer Mario , Flahault Antoine , Stoffel Markus
Published: November 2020

A probe of a patient, seeking help in an emergency ward of a French hospital in late December 2019 because of Influenza like symptoms, was retrospectively tested positive to COVID-19. Despite the early appearance of the virus in Europe, the prevalence and virulence appeared to be low for several weeks, before the spread and severity of symptoms increased exponentially, yet with marked spatial and temporal differences. Here, we compare the possible linkages between peaks of fine particulate matter (PM2.5) and the sudden, explosive increase of hospitalizations and mortality rates in the Swiss Canton of Ticino, and the Greater Paris and London regions. We argue that these peaks of fine particulate matter are primarily occurring during thermal inversion of the boundary layer of the atmosphere. We also discuss the influence of Saharan dust intrusions on the COVID-19 outbreak observed in early 2020 on the Canary Islands. We deem it both reasonable and plausible that high PM2.5 concentrations—favored by air temperature inversions or Saharan dust intrusions—are not only modulating but even more so boosting severe outbreaks of COVID-19. Moreover, desert dust events—besides enhancing PM2.5 concentrations—can be a vector for fungal diseases, thereby exacerbating COVID-19 morbidity and mortality. We conclude that the overburdening of the health services and hospitals as well as the high over-mortality observed in various regions of Europe in spring 2020 may be linked to peaks of PM2.5 and likely particular weather situations that have favored the spread and enhanced the virulence of the virus. In the future, we recommended to monitor not only the prevalence of the virus, but also to consider the occurrence of weather situations that can lead to sudden, very explosive COVID-19 outbreaks.
Anti-inflammatory and antibacterial effects of human cathelicidin active fragment KR-12 in the mouse models of colitis: a novel potential therapy of inflammatory bowel diseases
Authors: Fabisiak Natalia , Fabisiak Adam , Chmielowiec-Korzeniowska Anna , Tymczyna Leszek , Kamysz Wojciech , Kordek Radzisław , Bauer Marta , Kamysz Elżbieta , Fichna Jakub
Published: November 2020

Introduction

Inflammatory bowel diseases (IBD) are a group of chronic gastrointestinal tract disorders with complex etiology, with intestinal dysbiosis as the most prominent factor. In this study, we assessed the anti-inflammatory and antibacterial actions of the human cathelicidin LL-37 and its shortest active fragment, KR-12 in the mouse models of colitis.

Materials and methods

Mouse models of colitis induced by 2,4,6-trinitrobenzenesulfonic acid (TNBS) and dextran sulfate sodium (DSS) were used in the study. The extent of inflammation was evaluated based on the macro- and microscopic scores, quantification of myeloperoxidase (MPO) activity and microbiological analysis of stool samples.

Results

A preliminary study with LL-37 and KR-12 (1 mg/kg, ip, twice daily) showed a decrease in macroscopic and ulcer scores in the acute TNBS-induced model of colitis. We observed that KR-12 (5 mg/kg, ip, twice daily) reduced microscopic and ulcer scores in the semi-chronic and chronic TNBS-induced models of colitis compared with inflamed mice. Furthermore, qualitative and quantitative changes in colonic microbiota were observed: KR-12 (5 mg/kg, ip, twice daily) decreased the overall number of bacteria, Escherichia coli and coli group bacteria. In the semi-chronic DSS-induced model, KR-12 attenuated intestinal inflammation as demonstrated by a reduction in macroscopic score and colon damage score and MPO activity.

Conclusions

We demonstrated that KR-12 alleviates inflammation in four different mouse models of colitis what suggests KR-12 and cathelicidins as a whole are worth being considered as a potential therapeutic option in the treatment of IBD.
Sexual debut and college entrance among South Korean adolescents
Authors: Kim Hyun Sik
Published: November 2020

Introduction

For the past few decades, numerous theoretical perspectives have predicted a negative association between adolescent sexual debut and the probability of college entrance. The present article extends the literature by using nationally representative longitudinal data from South Korea to assess these perspectives.

Methods

Drawing on longitudinal data from South Korea, this article examined the impact of becoming sexually active between 8th and 12th grades on the probability of college entrance. We controlled for a wide array of confounding variables by using logit models that account for longitudinal attrition and school‐based sampling design.

Results

Analytical results showed that the initiation of sexual intercourse during adolescence predicted a statistically significant decrease in the probability of college entrance for both boys and girls. Gender‐specific analyses suggested that, on average, sexual debut in adolescence was associated with a decrease of 10.3 percentage points in the probability of college entrance for boys and a decrease of 14.7 percentage points for girls.

Conclusions

These findings strongly support the theoretical perspectives of age norm theory and sexual double standards in South Korea, where strictly conservative attitudes toward sexuality and sexual behaviors are dominant.
Analgesic effects of TAP block among open appendectomy patients and the need of postoperative pethidine for Pain Management: A randomised controlled trial
Authors: Shahmoradi Mohammad Kazem , Besharatifar Gholamreza , Taheri Hamid Reza
Published: November 2020

ABSTRACT

Background:

The transversus abdominis plane (TAP) block is an effective method to reduce postoperative pain and need of analgesics following abdominal surgeries.

Objective:

The aim of this study is to evaluate the effects of Marcaine (0.5% bupivacaine) TAP block on postoperative pain, patient recovery and the need of pethidine as an analgesic, following open appendectomy.

Method:

In this randomized blinded study, 96 patients undergoing open appendectomy were randomly divided into two equal groups of 48 patients. Group A received 20 cc of Marcaine (0.5% bupivacaine) under ultrasound guidance as TAP block and group B received 20 cc of normal saline as a control group. Under general anesthesia, patients underwent open appendectomy. The visual analogue scale (VAS) was used to measure postoperative pain along with the patient's need of pethidine, patient's satisfaction, duration of hospitalization, complications and recovery time (time to resume walking).

Result:

The two groups were had no statistically significant difference in terms of age, sex and BMI, P < 0.99, respectively. After adjusting the duration of the surgery and incision size, the duration of hospitalization, time of resume walking, patient satisfaction based on postoperative pain and the need of pethidine at 1, 3, 6, 12, 24 and 48 h were significantly different in the two groups, P < 0.001. Additionally, postoperative complications were not significantly different among the two groups.

Conclusion:

The results of the study indicate that TAP block before open appendectomy with Marcaine (0.5% bupivacaine) is effective to manage postoperative pain and is associated reduced need of postoperative analgesia and hospitalization.

Highlights:
Neorealist Film Culture, 1945–1954
Authors: Pitassio Francesco
Published: November 2020

Unique, truthful, brutal … Neorealism is often associated with adjectives stressing its peculiarities in representing the real, its lack of antecedents, and its legacy in terms of film style. While this is useful when confronting auteurs such as De Sica, Rossellini or Visconti, it becomes problematic when examining a widespread cultural practice that realistic modes deeply affected. This cultural production included filmmaking, literature, visual culture and photography, as well as media discourses. It was internally contradictory but fruitful inasmuch as its legacy influenced national culture for many decades to come. The volume spotlights post-war Italian film culture by locating a series of crossroads, i.e. topics barely examined when discussing neorealism: nation, memory and trauma, visual culture, stardom, and performance. The aim is to deconstruct neorealism as a monument and to open up its cultural history.
Representing from Life in Seventeenth-century Italy
Authors: McTighe Sheila
Published: November 2020

In drawing or painting from live models and real landscapes, more was at stake for artists in early modern Italy than achieving greater naturalism. To work with the model in front of your eyes, and to retain their identity in the finished work of art, had an impact on concepts of artistry and authorship, the authority of the image as a source of knowledge, the boundaries between repetition and invention, and even the relation of images to words. This book focuses on artists who worked in Italy, both native Italians and migrants from northern Europe. The practice of depicting from life became a self-conscious departure from the norms of Italian arts. In the context of court culture in Rome and Florence, works by artists ranging from Caravaggio to Claude Lorrain, Pieter van Laer to Jacques Callot, reveal new aspects of their artistic practice and its critical implications.
Saint Anthony's Fire from Antiquity to the Eighteenth Century
Authors: Foscati Alessandra
Published: November 2020

After the discovery of the ergotism epidemics (poisoning caused by ingesting the fungal toxin of rye) and its etiology, eighteenth-century physicians interpreted medieval chronicles in their medical texts in order to recognize the occurrences of ergotic diseases through retrospective diagnosis. They assumed that St. Anthony's fire and ignis sacer ("sacred fire") recorded in medieval texts represented the same disease, ergotism. This interpretative method, lacking a textual basis in the sources, has been incorrectly followed by historians till now. This book examines this historical prejudice through textual analysis, comparing diverse medieval and early modern sources. A striking semantic complexity emerges that changes the concept of St. Anthony's fire and modifies our understanding of diseases in general. This research illuminates aspects of the history of medicine, society, and hospitals.
Saints, Infirmity, and Community in the Late Middle Ages
Authors: Kuuliala Jenni
Published: November 2020

Bodily suffering and patient, Christlike attitudes towards that suffering were among the key characteristics of sainthood throughout the medieval period. Drawing on new work in medieval dis/ability studies, this book analyses the meanings given to putative saints' bodily infirmities in late medieval canonization hearings. How was an individual saint's bodily ailment investigated in the inquests, and how did the witnesses (re)construct the saintly candidates' ailments? What meanings were given to infirmity when providing proofs for holiness? This study depicts holy infirmity as an aspect of sanctity that is largely defined within the community, in continual dialogue with devotees, people suffering from doubt, the holy person, and the cultural patterns ascribed to saintly life. Furthermore, it analyses how the meanings given to saints' infirmities influenced and reflected society's attitudes towards bodily ailments in general.
Politics and Literature in Mongolia (1921–1948)
Authors: Wickhamsmith Simon
Published: November 2020

This study investigates the relationship between literature and politics during Mongolia's early revolutionary period. Between the 1921 socialist revolution and the first Writers' Congress, held in April 1948, the literary community constituted a key resource in the formation and implementation of policy. At the same time, debates within the party, discontent among the population, and questions of religion and tradition led to personal and ideological conflict among the intelligentsia and, in many cases, to trials and executions. Using primary texts, many of them translated into English for the first time, Simon Wickhamsmith shows the role played by the literary arts - poetry, fiction and drama - in the complex development of the new society
Building as Screen
Authors: Colangelo Dave
Published: November 2020

The Building as Screen: A History, Theory, and Practice of Massive Media describes, historicizes, theorizes, and creatively deploys massive media - a set of techno-social assemblages and practices that include large outdoor projections, programmable architectural façades, and urban screens -- in order to better understand their critical and creative potential. Massive media is named as such not only because of the size and subsequent visibility of this phenomenon but also for its characteristic networks and interactive screen and cinema-like qualities. Examples include the programmable lighting of the Empire State Building and the interactive projections of Montreal’s Quartier des spectacles, as well as a number of works created by the author himself. This book argues that massive media enables and necessitates the development of new practices of expanded cinema, public data visualization, and installation art and curation that blend the logics of urban space, monumentality, and the public sphere with the aesthetics and affordances of digital information and the moving image.
Transnational Play
Authors: Schleiner Anne-Marie
Published: November 2020

Transnational Play makes a case for approaching gameplay as a global industry and set of practices that also includes diverse participation from players and developers located within the global South, in nations outside of the First World. Such participation includes gameplay in cafes, games for regional and global causes like environmentalism, piracy and cheats, localization, urban playful art in Latin America, and the development of culturally unique mobile games. This book offers a reorientation of perspective on global play, while still acknowledging geographically distributed socioeconomic, racial, gender, and other inequities. Over the course of the inquiry, which includes a chapter dedicated to the cartography of the mobile augmented reality game Pokémon Go, the author develops a theoretical line of argument critically informed by gender studies and intersectionality, post-colonialism, geopolitics, and game studies. This book looks at who develops, localizes, and consumes games, problematizing play as a diverse and contested transnational domain.
Sense Knowledge and the Challenge of Italian Renaissance Art
Authors: Knox Giles
Published: November 2020

Giles Knox examines how El Greco, Velaìzquez, and Rembrandt, though a disparate group of artists, were connected by a new self-consciousness with respect to artistic tradition. In particular, Knox considers the relationship of these artists to the art of Renaissance Italy, and sets aside nationalist art histories in order to see the period as one of fruitful exchange. Across Europe during the seventeenth century, artists read Italian-inspired writings on art and these texts informed how they contemplated their practice. Knox demonstrates how these three artists engaged dynamically with these writings, incorporating or rejecting the theoretical premises to which they were exposed. Additionally, this study significantly expands our understanding of how paintings can activate the sense of touch. Knox discusses how Velaìzquez and Rembrandt, though in quite different ways, sought to conjure for viewers thoughts about touching that resonated directly with the subject matter they depicted.
Cross-border Mobility
Authors: Mee Wendy
Published: November 2020

Cross-border Mobility: Women, Work and Malay Identity in Indonesia offers a fresh perspective on the association between mobility and the ethnocultural category ‘Malay’. In so doing, it raises new research questions that are relevant to the study of Indonesian women’s socioeconomic mobility more generally. Based on fieldwork in Sambas, a region of Indonesia bordering Malaysia, this study documents the ethnocultural consequences of the highly mobile working lives of Sambas Malay women. Emphasising the significance of territorial borders in women’s working lives, this study highlights how women’s border location not only facilitates cross-border pathways of international labour migration and trade, but also generates feelings of peripherality that inform women’s imaginative construction of other, nonterritorial borders that need to be crossed. Shaped by social class, gender, and the economic and cultural possibilities of political decentralization, the study identifies three borderscopes that orient women’s work-related mobility and create diverse outcomes for the ethnocultural category 'Sambas Malay'.
History and Philosophy of the Humanities
Authors: de Vries Gerard , Leezenberg Michiel
Published: November 2020

The humanities include disciplines as diverse as literary theory, linguistics, history, film studies, theology, and philosophy. Do these various fields of study have anything in common that distinguishes them from, say, physics or sociology? The tripartite division between the natural sciences, the social sciences and the humanities may seem self-evident, but it only arose during the course of the 19th century and is still contested today. History and Philosophy of the Humanities: An Introduction presents a reasoned overview of the conceptual and historical backgrounds of the humanities. In four sections, it discusses: the most influential views on scientific knowledge from Aristotle to Thomas Kuhn; the birth of the modern humanities and its relation to the natural and social sciences; the various methodological schools and conceptual issues in the humanities; several themes that set the agenda for current debates in the humanities: critiques of modernity; gender, sexuality and identity; and postcolonialism. Thus, it provides students in the humanities with a comprehensive understanding of the backgrounds of their own discipline, its relation to other disciplines, and the state of the art of the humanities at large.
Stability Analysis of Fragile Rock Pillars and Insights on Fault Activity in the Negev, Israel
Authors: Finzi Yaron , Ganz Noam , Dor Ory , Davis Michael , Volk Omri , Langer Sebastian , Arrowsmith Ramon , Tsesarsky Michael
Published: November 2020

Fragile geologic features (FGFs) are used as negative indicators of strong ground motion. By evaluating the stability of FGFs and determining their age, it is possible to constrain the local maximum seismic ground acceleration that has occurred during their lifetime. This methodology was originally developed to analyze precariously balanced rocks (a subset of FGFs) and has been used to assess long‐term fault activity and improve seismic hazard analyses. In the Negev desert of Israel, several in situ, slender rock pillars exhibit natural frequencies within the range of seismic waves (1–10 Hz) and therefore constitute an important FGF subset. However, the motion of such pillars may be complex with an initial stage of swaying followed by basal detachment, rocking and toppling, or failure within the pillar. To demonstrate that pillar stability can be analyzed using the existing FGF methodology, we show that the tensional stresses developed at the base of a pillar swaying at its fundamental modes of motion are comparable or larger than the typical tensile strength of Negev pillars. Finally, we demonstrate how a newly documented data set of Negev FGFs can be used to provide new insights on fault activity along the Negev‐Sinai Shear Zone and the Arava Fault. Assuming a plausible range of motion amplification, the stability analysis of long‐standing FGFs yields significant constraints on fault seismicity parameters (Mmax < 7 for a section of the Arava Fault). Extending the regional data set would provide important insights for regional seismic hazard along the Dead Sea Transform.
Using Prophet Forecasting Model to Characterize the Temporal Variations of Historical and Future Surface Urban Heat Island in China
Authors: Li Long , Zha Yong , Zhang Jiahua , Li Yunmei , Lyu Heng
Published: November 2020

The changes in surface urban heat island (SUHI) are usually diurnal variations, seasonal variations, and interannual trends, yet previous temporal analysis methods have difficulties in decomposing time‐series SUHI intensity (SUHII) into multiple time scales. This study proposed a prophet forecasting model to decompose time‐series SUHII in 102 Chinese cities for the analysis of temporal variations. The occurrence time of SUHII extremums and annual SUHII amplitude (ASA) were investigated. Results show that the maximum daytime SUHII in 88% of the cities occurred in summer, and the minimum daytime SUHII in 80% of the cities occurred in winter. At night, the maximum SUHII in northern cities occurred in the cold season, while the minimum SUHII occurred in the hot season, which is the opposite of the results of southern cities. Larger ASA was observed in northern cities than southern cities, and the ASA was larger during the day than night. The interannual trend of SUHII was characterized and the SUHII in 2030 was predicted. Results show that the increasing trends of SUHII were found in 78% and 83% of the cities in the day and night, respectively. The interannual trend of daytime SUHII was negative (−0.01 ± 0.28°C/10 yr) in northern cities, while it was positive (0.22 ± 0.20°C/10 yr) in southern cities. At night, northern cities (0.19 ± 0.12°C/10 yr) had a faster increasing trend of SUHII than southern cities (0.06 ± 0.13°C/10 yr). The SUHII in China will be more evident in 2030, and various mitigation measures are needed for SUHII mitigation.
Late Miocene Deformation Kinematics Along the NW Zagros Fold‐Thrust Belt, Kurdistan Region of Iraq: Constraints From Apatite (U‐Th)/He Thermochronometry and Balanced Cross Sections
Authors: Koshnaw Renas I. , Stockli Daniel F. , Horton Brian K. , Teixell Antonio , Barber Douglas E. , Kendall Jerome J.
Published: November 2020

Apatite (U‐Th)/He (AHe) thermochronometric results are integrated with geologic cross sections, structural relationships, and stratigraphic data to reconstruct the growth of the NW Zagros orogenic belt in the Kurdistan region of Iraq. Prolonged exhumation is documented across the belt with deformation advances and retreats from ~14 Ma onward. After in‐sequence propagation of deformation during middle to late Miocene times, preserved growth strata and AHe data show a deformation retreat by latest Miocene time (~5 Ma). In the NW Zagros, the Phanerozoic succession contains two principal décollements in Lower Triassic and middle Miocene units. The Triassic strata are interpreted as the main décollement for a thin‐skinned system that was dominant during most of the Cenozoic. By ~8–5 Ma, the fold‐thrust belt shifted to basement‐involved deformation in association with growth of the mountain front flexure and reactivation of frontal structures. The shift from thin‐skinned to a hybrid thin‐ and thick‐skinned mode of shortening may reflect variations in the mechanical behavior of the upper crust and the presence of inherited basement discontinuities. On the basis of two NE‐SW balanced cross sections spanning the NW Zagros, the estimated total minimum horizontal shortening is ~18.2 km (6%) in the central and ~16 km (7%) in the southern sectors of the Kurdistan region of Iraq. These findings suggest that the evolution of the NW Zagros orogenic belt was likely driven by the mechanical stratigraphy of the sedimentary cover, inherited basement discontinuities, and the dynamic and thermomechanical effects of potential slab breakoff and lithospheric mantle delamination events.
The USDA‐ARS Experimental Watershed Network: Evolution, Lessons Learned, Societal Benefits, and Moving Forward
Authors: Goodrich D. C. , Heilman P. , Anderson M. , Baffaut C. , Bonta J. , Bosch D. , Bryant R. , Cosh M. , Endale D. , Veith T. L. , Havens S. C. , Hedrick A. , Kleinman P. J. , Langendoen E. J. , McCarty G. , Moorman T. , Marks D. , Pierson F. , Rigby J. R. , Schomberg H. , Starks P. , Steiner J. , Strickland T. , Tsegaye T.
Published: November 2020

The U.S. Department of Agriculture‐Agricultural Research Service's (ARS) Experimental Watershed Network grew from Dust Bowl era efforts of the Soil Conservation Service in the mid‐1930s with the establishment of small experimental watersheds. In the 1950s, five watershed research centers with intensively instrumented watersheds at the scale of 100 to 700 km2 were established. Primary network research objectives were to quantify on‐site and downstream effects of conservation practices and develop rainfall‐runoff relationships for design of water conservation structures. With passage of the Clean Water Act in 1972, research objectives have evolved to add a variety of observations relevant to the water quality issues. Many of the watersheds within the network have served, and continue to serve, as core validation sites for satellite sensors. As a result of the network's long history and intensive monitoring, coupled with mission‐driven research, a deep knowledge base of watershed processes has been developed. This has led to the extensive development and validation of numerous watershed models that are in widespread use today. The visionary investments in building and maintaining this network and associated scientific investigations for more than half a century have not only resulted in numerous high‐impact research accomplishments but also a wide array of accomplishments that directly benefit society. The ARS Experimental Watersheds formed the core of the Conservation Effects Assessment Project (CEAP) as well as the recently established Long‐Term Agroecosystem Research (LTAR) network. LTAR will expand the mission of the ARS Watersheds Network to include agricultural intensification, maintaining or improving ecosystem services while enhancing rural prosperity.
ICESat‐2/ATLAS Onboard Flight Science Receiver Algorithms: Purpose, Process, and Performance
Authors: McGarry J. F. , Carabajal C. C. , Saba J. L. , Reese A. R. , Holland S. T. , Palm S. P. , Swinski J.‐P. A. , Golder J. E. , Liiva P. M.
Published: November 2020

The Advanced Topographic Laser Altimetry System (ATLAS) is the sole instrument on the Ice, Cloud, and land Elevation Satellite 2 (ICESat‐2). Without some method of reducing the transmitted data, the volume of ATLAS telemetry would far exceed the normal X‐band downlink capability or require many more ground station contacts. The ATLAS Onboard Flight Science Receiver Algorithms (hereinafter Receiver Algorithms or Algorithms) control the amount of science data that is telemetered from the instrument, limiting the data volume by distinguishing surface echoes from background noise, and allowing the instrument to telemeter data from only a small vertical region about the signal. This is accomplished through the transfer of the spacecraft's location and attitude to the instrument every second, use of an onboard Digital Elevation Model, implementation of signal processing techniques, and use of onboard relief and surface type reference maps. Extensive ground testing verified the performance of the Algorithms. On‐orbit analysis shows that the Algorithms are working as expected from the ground testing; they are performing well and meeting the mission requirements.
The State of the Art in Modeling Waterlogging Impacts on Plants: What Do We Know and What Do We Need to Know
Authors: Liu Ke , Harrison Matthew Tom , Shabala Sergey , Meinke Holger , Ahmed Ibrahim , Zhang Yunbo , Tian Xiaohai , Zhou Meixue
Published: November 2020

Models are key tools in our quest to better understand the impacts of soil waterlogging on plant growth and crop production. Here, we reviewed the state of the art of modeling approaches and compared the conceptual design of these models with recent experimental findings. We show that many models adopt an aeration stress (AS) principle where surplus water reduces air‐filled porosity, with implications for root growth. However, subsequent effects of AS within each model vary considerably. In some cases, AS inhibits biomass accumulation (e.g. AquaCrop), altering processes prior to biomass accumulation such as light interception (e.g. APSIM), or photosynthesis and carbohydrate accumulation (e.g. SWAGMAN Destiny). While many models account for stage‐dependent waterlogging effects, few models account for experimentally observed delays in phenology caused by waterlogging. A model intercomparison specifically designed for long‐term waterlogged conditions (APSIM‐Oryza) with models developed for dryland conditions with transient waterlogging would advance our understanding of the current fitness for purpose of exsiting frameworks for simulating transient waterlogging in dryland cropping systems. Of the point‐based dynamic models examined here, APSIM‐Soybean and APSIM‐Oryza simulations most closely matched with the observed data, while GLAM‐WOFOST achieved the highest performance of the spatial‐regional models examined. We conclude that future models should incorporate waterlogging effects on genetic tolerance parameters such as (1) phenology of stress onset, (2) aerenchyma, (3) root hydraulic conductance, (4) nutrient‐use efficiency, and (5) plant ion (e.g. Fe/Mn) tolerance. Incorporating these traits/effects into models, together with a more systematic model intercomparison using consistent initialization data, will significantly improve our understanding of the relative importance of such factors in a systems context, including feedbacks between biological factors, emergent properties, and sensitive variables responsible for yield losses under waterlogging.
Southern Ocean Calcification Controls the Global Distribution of Alkalinity
Authors: Krumhardt K. M. , Long M. C. , Lindsay K. , Levy M. N.
Published: November 2020

Biological processes in Southern Ocean surface waters have widespread impacts on global productivity and oceanic CO2 storage. Here, we demonstrate that biological calcification in the Southern Ocean exerts a strong control on the global distribution of alkalinity. The signature of Southern Ocean calcification is evident in observations as a depletion of potential alkalinity within portions of Subantarctic Mode and Intermediate Water. Experiments with an ocean general circulation model indicate that calcification and subsequent sinking of biogenic carbonate in this region effectively transfers alkalinity between the upper and lower cells of the meridional overturning circulation. Southern Ocean calcification traps alkalinity in the deep ocean; decreasing calcification permits more alkalinity to leak out from the Southern Ocean, yielding increased alkalinity in the upper cell and low‐latitude surface waters. These processes have implications for atmosphere‐ocean partitioning of carbon. Reductions in Southern Ocean calcification increase the buffer capacity of surface waters globally, thereby enhancing the ocean's ability to absorb carbon from the atmosphere. This study highlights the critical role of Southern Ocean calcification in determining global alkalinity distributions, demonstrating that changes in this process have the potential for widespread consequences impacting air‐sea partitioning of CO2.
Mapping Artisanal and Small‐Scale Gold Mining in Senegal Using Sentinel 2 Data
Authors: Ngom N. M. , Mbaye M. , Baratoux D. , Baratoux L. , Catry T. , Dessay N. , Faye G. , Sow E. H. , Delaitre E.
Published: November 2020

Artisanal and small‐scale gold mining (ASGM) represents a significant economic activity for communities in developing countries. In southeastern Senegal, this activity has increased in recent years and has become the main source of income for the local population. However, it is also associated with negative environmental, social, and health impacts. Considering the recent development of ASGM in Senegal and the difficulties of the government in monitoring and regulating this activity, this article proposes a method for detecting and mapping ASGM sites in Senegal using Sentinel 2 data and the Google Earth Engine. Two artisanal mining sites in Senegal are selected to test this approach. Detection and mapping are achieved following a processing pipeline. Principal component analysis (PCA) is applied to determine the optimal period of the year for mapping. Separability and threshold (SEaTH) is used to determine the optimal bands or spectral indices to discriminate ASGM from other land use. Finally, automatic classification and mapping of the scenes are achieved with support vector machine (SVM) classifier. The results are then validated based on field observations. The PCA and examination of spectral signatures as a function of time indicate that the best period for discriminate ASGM sites against other types of land use is the end of dry season, when vegetation is minimal. The classification results are presented as a map with different categories of land use. This method could be applied to future Sentinel scenes to monitor the evolution of mining sites and may also be extrapolated to other relevant areas in the Sahel.
Relation Between Shock‐Related Impulse and Subsequent ULF Wave in the Earth's Magnetosphere
Authors: Zhang Dianjun , Liu Wenlong , Li Xinlin , Sarris Theodore E. , Wang Yongfu , Xiao Chao , Zhang Zhao , Wygant John R.
Published: November 2020

The generation of Pc4‐5 ultralow frequency (ULF) waves after interplanetary shock‐induced electric field impulses in the Earth's magnetosphere is studied using Van Allen Probes measurements by investigating the relationship between the first impulses and subsequent resonant ULF waves. In the dayside, the relevant time scales of the first impulse is correlated better with local Alfvén speed than with local eigenfrequency, implying that the temporal scale of the first impulse is more likely related to fast‐mode wave propagation rather than local field line resonance. There are only 20 out of 51 events with narrow‐band poloidal ULF waves induced after the first impulse, showing a higher chance for ULF wave generation at the locations where the impulse equivalent frequency scale matches the local eigenfrequency. It is suggested that the shock‐related ULF wave can be excited in the magnetosphere on condition that shock‐induced impulse has large enough amplitude with its frequency matching the local eigenfrequency.
Moisture‐ Versus Wind‐Dominated Flavors of Atmospheric Rivers
Authors: Gonzales Katerina R. , Swain Daniel L. , Barnes Elizabeth A. , Diffenbaugh Noah S.
Published: November 2020

Atmospheric rivers (ARs) are essential features of the global water cycle. Although AR definitions are commonly based on integrated vapor transport (IVT), ARs of a given IVT can induce a wide range of surface precipitation and wind impacts. We develop an AR “flavor” metric that partitions AR IVT into moisture‐dominant and wind‐dominant components. We use this metric to create a climatological catalog of “wet” and “windy” ARs along the U.S. West Coast from 1980 to 2016. Windy ARs are generally associated with stronger surface winds than are wet ARs, with the largest differences at low IVT. Windy ARs are also associated with greater daily precipitation totals than are wet ARs, with the difference widening at higher IVT, notably over mountainous regions. Pacific Northwest ARs have become increasingly moisture dominated over 1980–2016, which has important implications for western U.S. water availability and flood risk.
Temporal Evolution of Flux Tube Entanglement at the Magnetopause as Observed by the MMS Satellites
Authors: Qi Y. , Russell C. T. , Jia Ying‐Dong , Hubbert M.
Published: November 2020

Flux transfer events (FTEs), as flux ropes (FRs), are considered key agents for solar wind energy to enter the terrestrial magnetosphere. Recent observations identify entangled flux tubes that collide and pull against each other. Reconnection occurs to disentangle and produce a new pair of FRs with different connectivity. In this paper, we examine the entanglement interface and how such an entanglement process evolves in time by comparing 17 entanglements observed by the Magnetospheric Multiscale (MMS) mission. The By‐dominated interplanetary magnetic field (IMF) distribution of the 17 events agrees with previous findings. We have identified three evolutionary stages characterized by the magnetic field and pressure enhancement. Our study confirms the FR nature of these events and explains how a disparate pair of ropes is formed from two entangled flux tubes, each initially connected to a different hemisphere of the magnetosphere.
Nonlinear Interactions Between Relativistic Electrons and EMIC Waves in Magnetospheric Warm Plasma Environments
Authors: Yu Jiang , Li L. Y. , Cui Jun , Cao J. B. , Wang Jing , He Zhaoguo , Yang Jian
Published: November 2020

With the kinetic dispersion relation and test particle simulation, we examine the effect of hot protons on the nonlinear interactions of relativistic electrons with electromagnetic ion cyclotron (EMIC) waves. We find that hot protons alter the refractive index of EMIC waves at a given wave frequency along latitude and thus modify resonance latitude. Consequently, resonance refractive index gradient along the magnetic field line, which plays a dominant role in controlling the electron behaviors, changes. Overall, the involvement of hot protons enlarges the resonance region (linear and nonlinear) but narrows the nonlinear resonance region. Additionally, hot protons weaken the electron phase bunching process and shift the electron phase trapping region to larger equatorial pitch angles. When the abundance or temperature anisotropy of hot protons increases, their effects on electron behaviors become more significant.
Multiple Technique Observations of the Ionospheric Responses to the 21 June 2020 Solar Eclipse
Authors: Zhang Ruilong , Le Huijun , Li Wenbo , Ma Han , Yang Yuyan , Huang He , Li Qiaoling , Zhao Xiukuan , Xie Haiyong , Sun Wenjie , Li Guozhu , Chen Yiding , Zhang Hui , Liu Libo
Published: November 2020

We investigate the ionospheric response to the 21 June 2020 annular solar eclipse using the multiinstrument observations including ionosondes, Global Navigation Satellite System (GNNS) receivers, COSMIC2, and DMSP and SWARM satellites. During the course of the eclipse, total electron content (TEC) decreased slightly in the morning at 20–70°E and largely in the afternoon at 80–150°E. However, maximum TEC depletion did not occur at the maximum obscuration, but stayed close to the southern edge of the running totality during the eclipse and near the northern edge of the elapsed totality after the eclipse. NmF2 showed the similar variation as TEC around 110°E. Meanwhile, a northward disturbance field‐aligned plasma drift was observed in the eclipse region and the disturbance became strong in the southern side of the totality around 120°E. The TEC and Swarm data revealed that the crests of the equatorial ionization anomaly (EIA) enhanced on both sides of the equator around noon in ~50–100°E although the northern crest was still in the Moon's shadow. The COSMIC2 profiles displayed the enhanced electron density in ~300–500 km altitudes and decreased density below ~300 km altitudes around the EIA crests in ~70°E. The Swarm observations recorded a drop in the electron temperature both in eclipse region and in conjugate hemisphere in 77°E and 96°E. The combined effect from the electric field, neutral wind, thermal conduction, and interhemispheric photoelectron transport might result in the complicated space and time variations of ionospheric responses to the eclipse.
Westward Electric Fields in the Afternoon Equatorial Ionosphere During Geomagnetically Quiet Times
Authors: Zhang Ruilong , Liu Libo , Yu You , Le Huijun , Chen Yiding
Published: November 2020

The daytime average zonal electric field is well known to be eastward in the equatorial ionosphere. Geomagnetic observations have revealed that the equatorial electrojet or zonal electric field occasionally becomes westward in the afternoon sector during quiet times. We present the first analysis of the dependence of the afternoon downward plasma drifts on the season, longitude, solar activity, and lunar phase using the ROCSAT‐1 satellite observations during 1999–2004. The results show that there are ~20% of downward plasma drifts at 13–17 LT. The occurrence rate of the downward plasma drift shows a peak around January and a secondary peak in July. The occurrence rate presents a slight decrease trend with the solar activity. Especially, the occurrence rate can attain ~40–50% around 60°E in June solstice and 145–245°E in December solstice, which is nearly comparable with the occurrence rate of the upward plasma drifts in these longitudes. The downward plasma drift occurs most frequently around the full moon in the afternoon sector. The geomagnetic declination induces the hemispheric differences in the dynamo current in the conjugate regions and controls the occurrence of the westward electric fields. A wavenumber‐4 longitudinal structure also appears to be present in the occurrence rate in June–September, and the wavenumber‐4 peak coincides with the diurnal eastward tidal wind, which drives the generation of the westward electric fields.
Pore‐Scale 3D Morphological Modeling and Physical Characterization of Hydrate‐Bearing Sediment Based on Computed Tomography
Authors: Wu Peng , Li Yanghui , Sun Xiang , Liu Weiguo , Song Yongchen
Published: November 2020

Natural gas hydrate is considered to be a promising future energy resource; therefore, obtaining its physical properties is crucial for evaluating gas production efficiency and developing reasonable exploitation strategies. In this study, we present a novel pore‐scale 3D morphological modeling algorithm considering various saturation and occurrences (cementing and pore‐filling) of hydrate in sediments. To evaluate the performance of the presented algorithm, 14 hydrate‐bearing sediment models were constructed based on X‐ray computed tomographic images of a consolidated sandy specimen under an effective stress of 3 MPa. Morphologically, the new algorithm generated pore‐scale hydrate occurrences coincide with published morphological behaviors of hydrate observed via computed tomography. The tortuosity and fractal dimension of pore spaces of these models were then characterized. The pore networks are also extracted, based on which the evolution of the pore characteristics including the distributions of pore radius, throat radius, throat length, and the coordination number were investigated. Using these generated models, simulations of permeability, thermal conductivity, and electrical conductivity were conducted to evaluate the influences of hydrate saturation and occurrence. These results are validated against published data, demonstrating that this algorithm could be an effective way to construct digital hydrate‐bearing sediment models using a single set of computed tomographic images of a hydrate‐free specimen. This new method can also be significant for the physical evaluation of natural cores in which hydrate has dissociated during core recovering and transferring.