bluuebunny/crossref_metadata_2025 huggingface dataset:
Conductive and tribological properties of TiN-Ag composite coatings under grease lubrication
Authors: Lin Feihu , Xia Yanqiu , Feng Xin
Published: August 2020

TiN-Ag composite coatings were prepared by pulsed bias arc ion plating. X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS) were applied to analyze the compositions of the coatings. Tribological properties of the coatings were studied using an MFT-R4000 ball-on-disk friction tester in the presence of lubricating greases containing multilayer graphene. Scanning electron microscopy (SEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) were used to analyze the worn surface compositions of the lubricating films. The results show that with the decrease in Ag in the film, hardness increased but electrical conductivity decreased. The coating with 10 at% Ag content shows the best friction-reducing and anti-wear properties, which can be attributed to the moderate content of Ag embedded in the TiN crystal gap that enhanced the grain bonding force to improve the anti-wear and self-lubricating ability. Graphene can be adsorbed on the coating as a solid lubricant.
Societal and Ethical Issues in HRI
Authors: Wullenkord Ricarda , Eyssel Friederike
Published: August 2020

Purpose of the Review

The purpose of this review is to give an overview of the societal and ethical issues in human-robot interaction, (HRI), mainly focusing on the literature of the last five years.

Recent Findings

Both general ethical challenges associated with robot deployment and those specific to human-robot interaction are addressed and complemented by discussions of ethics within HRI research, ethics related behavior towards robots, as well as ethics and robot rights. Moreover, we discuss ethical challenges in sensitive contexts such as medicine, rehabilitation, and care. We conclude our review by providing an overview of the key ethics frameworks and guidelines to inspire researchers, developers, and stakeholders alike.

This review offers a timely overview of the state-of-the art societal and ethical issues that arise from the ever more steady integration of robots into human society. We exemplify the key issues and debates in the field by mainly covering the literature of the past five years.
The Flying and the Masked Man, One More Time: Comments on Peter Adamson and Fedor Benevich, ‘The Thought Experimental Method: Avicenna's Flying Man Argument’
Authors: KAUKUA JARI
Published: August 2020

This is a critical comment on Adamson and Benevich (2018), published in issue 4/2 of the Journal of the American Philosophical Association. I raise two closely related objections. The first concerns the objective of the flying man: instead of the question of what the soul is, I argue that the argument is designed to answer the question of whether the soul exists independently of the body. The second objection concerns the expected result of the argument: instead of knowledge about the quiddity of soul, I claim the argument yields knowledge about the soul's existence independently of the body. After the objections, I turn to the masked man fallacy, claiming that although the Adamson-Benevich interpretation does save the argument from the fallacy, this comes at the cost of plausibility. I then give a more modest interpretation that both avoids the fallacy and is plausible. The paper concludes with a remark about the metaphysical possibility of the flying man.
Complementary and Alternative Therapy Use in Children with Cerebral Palsy
Authors: Oskoui Maryam , Ng Pamela , Zaman Michele , Buckley David , Kirton Adam , van Rensburg Esias , Wood Ellen , Shevell Michael , Majnemer Annette
Published: August 2020

Objective:

To describe complementary and alternative medicine (CAM) use amongst children with cerebral palsy (CP) in Canada and to identify factors associated with CAM use.

Methods:

We conducted a cross-sectional study, utilising data from the Canadian CP Registry. We explored the association between CAM use and regional, socioeconomic and CP phenotypic variables, and parental perception of the family-centredness of clinical care using the Measures of Process of Care-56 (MPOC-56). Chi-square analyses were performed, and odds ratios (OR) and 95% confidence intervals (CI) were obtained. Mann–WhitneyUtests were used to compare MPOC-56 scores between CAM users and non-CAM users.

Results:

The study sample consisted of 313 families of which 27% reported CAM use in the past year. Children with CP using CAM were more likely to reside in Western Canada (OR 3.3, 95% CI 1.6–6.7), live in a two-parent household (OR 3.5, 95% CI 1.5–8.4), have an ataxic/hypotonic or dyskinetic CP subtype (OR 3.0, 95% CI 1.5–6.1) and have a greater motor impairment (OR 2.8, 95% CI 1.7–4.9). MPOC-56 subscale scores were not significantly associated with CAM use.

Conclusion:

Physicians need to be aware of existing CAM therapies, the level of evidence supporting their efficacy (beneficence), their associated risks of adverse events (non-maleficence) and enable fair access to care that may be of benefit to each child.
COVID-19: public health management of the first two confirmed cases identified in the UK
Authors: Holden B. , Quinney A. , Padfield S. , Morton W. , Coles S. , Manley P. , Wensley A. , Hutchinson C. , Lillie P. J. , Duncan C. J. A. , Schmid M. L. , Li A. , Foster K. , Anaraki S. , Dabrera G. , Zambon M. , Hughes G. J. , Gent M.
Published: August 2020

We report key learning from the public health management of the first two confirmed cases of COVID-19 identified in the UK. The first case imported, and the second associated with probable person-to-person transmission within the UK. Contact tracing was complex and fast-moving. Potential exposures for both cases were reviewed, and 52 contacts were identified. No further confirmed COVID-19 cases have been linked epidemiologically to these two cases. As steps are made to enhance contact tracing across the UK, the lessons learned from earlier contact tracing during the country's containment phase are particularly important and timely.
Exploring influences on adolescent diet and physical activity in rural Gambia, West Africa: food insecurity, culture and the natural environment
Authors: Janha Ramatoulie E , Hardy-Johnson Polly , Kehoe Sarah H , Mendy Michael B , Camara Isatou , Jarjou Landing , Ward Kathryn , Moore Sophie E , Fall Caroline , Barker Mary , Weller Susie
Published: August 2020

Objective:

To explore, from the perspectives of adolescents and caregivers, and using qualitative methods, influences on adolescent diet and physical activity in rural Gambia.

Design:

Six focus group discussions (FGD) with adolescents and caregivers were conducted. Thematic analysis was employed across the data set.

Setting:

Rural region of The Gambia, West Africa.

Participants:

Participants were selected using purposive sampling. Four FGD, conducted with forty adolescents, comprised: girls aged 10–12 years; boys aged 10–12 years; girls aged 15–17 years, boys aged 15–17 years. Twenty caregivers also participated in two FGD (mothers and fathers).

Results:

All participants expressed an understanding of the association between salt and hypertension, sugary foods and diabetes, and dental health. Adolescents and caregivers suggested that adolescent nutrition and health were shaped by economic, social and cultural factors and the local environment. Adolescent diet was thought to be influenced by: affordability, seasonality and the receipt of remittances; gender norms, including differences in opportunities afforded to girls, and mother-led decision-making; cultural ceremonies and school holidays. Adolescent physical activity included walking or cycling to school, playing football and farming. Participants felt adolescent engagement in physical activity was influenced by gender, seasonality, cultural ceremonies and, to some extent, the availability of digital media.

Conclusions:

These novel insights into local understanding should be considered when formulating future interventions. Interventions need to address these interrelated factors, including misconceptions regarding diet and physical activity that may be harmful to health.
Assessment of crop and weed management strategies prior to introduction of auxin-resistant crops in Brazil
Authors: Oliveira Maxwel C. , Lencina Anelise , Ulguim André R. , Werle Rodrigo
Published: August 2020

A stakeholder survey was conducted from April through June of 2018 to understand stakeholders’ perceptions and challenges about cropping systems and weed management in Brazil. The dominant crops managed by survey respondents were soybean (73%) and corn (66%). Approximately 75% of survey respondents have grown or managed annual cropping systems with two to three crops per year cultivated in succession. Eighteen percent of respondents manage only irrigated cropping systems, and over 60% of respondents adopt no-till as a standard practice. According to respondents, the top five troublesome weed species in Brazilian cropping systems are horseweed (asthmaweed, Canadian horseweed, and tall fleabane), sourgrass, morningglory, goosegrass, and dayflower (Asiatic dayflower and Benghal dayflower). Among the nine species documented to have evolved resistance to glyphosate in Brazil, horseweed and sourgrass were reported as the most concerning weeds. Other than glyphosate, 31% and 78% of respondents, respectively, manage weeds resistant to acetyl-CoA carboxylase (ACCase) inhibitors and/or acetolactate synthase (ALS) inhibitors. Besides herbicides, 45% of respondents use mechanical, and 75% use cultural (e.g., no-till, crop rotation/succession) weed control strategies. Sixty-one percent of survey respondents adopt cover crops to some extent to suppress weeds and improve soil chemical and physical properties. Nearly 60% of survey respondents intend to adopt the crops that are resistant to dicamba or 2,4-D when available. Results may help practitioners, academics, industry, and policy makers to better understand the bad and the good of current cropping systems and weed management practices adopted in Brazil, and to adjust research, education, technologies priorities, and needs moving forward.
Herbicidal activity and molecular docking study of novel PPO inhibitors
Authors: Zhao Li-Xia , Jiang Mao-Jun , Hu Jia-Jun , Zou Yue-Li , Gao Shuang , Fu Ying , Ye Fei
Published: August 2020

Protoporphyrinogen oxidase (PPO) is an important target for discovering new herbicides that interfere with the synthesis of porphyrin. To discover new PPO inhibitors with improved biological activity, a series of new diphenyl ethers containing tetrahydrophthalimide were designed and synthesized. Among them, J6.1 (IC50 = 4.7 nM) and J6.3 (IC50 = 30.0 nM) show higher maize (Zea mays L.) PPO inhibitory activity than the commercial herbicides oxyfluorfen (IC50 = 117.9 nM) and flumioxazin (IC50 = 157.1 nM). The greenhouse herbicidal activity of J6.3 is comparable to that of oxyfluorfen, and it is greater than that of flumioxazin. Even at a dose of 300 g ai ha−1, cotton (Gossypium hirsutum L.) and peanut (Arachis hypogaea L.) show greater tolerance to J6.3, suggesting that J6.3 could be used for further development of new herbicide candidates in those fields. In addition, molecular docking has been used to further study the mechanism of action of J6.3. The results show that the introduction of a nitro group and tetrahydrophthalimide into the diphenyl ether structure is beneficial to biological activity.
Balloons in the Earth's Auroral Science—BALBOA's Modern Exploration
Authors: Zhou X.‐Y. , Rafol S. B. , Michell R. G. , Hampton D. , Geach C. , Berk A. , Lummerzheim D. , He Y.‐T.
Published: August 2020

Since 1892, when an aurora was first imaged by Martin Brendel, a German physicist, auroral forms and their dynamics have been acquired only when the aurora is in darkness. Due to the sunlight contamination from Rayleigh scattering, it has been a long‐term challenge of imaging sunlit aurora. In addition, other constraints exist, such as moonlight contamination, cloud occultation, and the limited land area available for installing imagers near the auroral zone in both hemispheres. While auroral imaging from space provides auroral global dynamics or small‐scale structures, depending on the spacecraft orbit, the image quality is affected by low spatial and temporal resolutions, sunlight, and the lack of traceability of auroral variations. Consequently, we have little knowledge of sunlit auroral forms and their dynamics, as well as their coupling to conjugate aurora. Given the fact that the solar wind‐magnetosphere‐ionosphere coupling is initiated on the dayside, understanding sunlit and dayside aurorae becomes very interesting and important. A scenario of imaging sunlit aurora from a balloon and the conceptual design of the instrument have been depicted in our previous article (Zhou et al., 2017, https://doi.org/10.1029/2006GL028611). This paper elaborates the new science enabled by this new means and the feasibility of auroral ballooning by showing some sunlit auroral images obtained from a balloon flight and calculations of the corresponding sky brightness. In addition, we describe and explain the most important specs of the new NIR camera‐head being developed for the BALBOA balloon mission that is currently supported by the NASA/Low Cost Access to Space program.
Atmospheric Gravity Waves Observed in the Nightglow Following the 21 August 2017 Total Solar Eclipse
Authors: Paulino I. , Figueiredo C. A. O. B. , Rodrigues F. S. , Buriti R. A. , Wrasse C. M. , Paulino A. R. , Barros D. , Takahashi H. , Batista I. S. , Medeiros A. F. , Batista P. P. , Abdu M. A. , de Paula E. R. , Denardini C. M. , Lima L. M. , Cueva R. Y.C. , Makela J. J.
Published: August 2020

Nighttime airglow images observed at the low‐latitude site of São João do Cariri (7.4°S, 36.5°W) showed the presence of a medium‐scale atmospheric gravity wave (AGW) associated with the 21 August 2017 total solar eclipse. The AGW had a horizontal wavelength of ∼1,618 km, observed period of ∼152 min, and propagation direction of ∼200° clockwise from the north. The spectral characteristics of this wave are in good agreement with theoretical predictions for waves generated by eclipses. Additionally, the wave was reverse ray‐traced, and the results show its path crossing the Moon's shadow of the total solar eclipse in the tropical North Atlantic ocean at stratospheric altitudes. Investigation about potential driving sources for this wave indicates the total solar eclipse as the most likely candidate. The optical measurements were part of an observational campaign carried out to detect the impact of the August 21 eclipse in the atmosphere at low latitudes.
Hyporheic Exchange Under Undular Flows Over a Coarse Granular Bed
Authors: Shih WuRong , Wu Fu‐Chun
Published: August 2020

Undular flows over riffles (standing waves with underlying open‐channel flows) facilitate a quality environmental setting for riverine habitats. Understanding their link with hyporheic exchange flow (HEF) is important from eco‐hydro‐geomorphic perspectives. We conduct refractive index‐matched scanning experiments to resolve the exchange between surface and subsurface flows across a coarse granular bed. We show that the HEF includes wave pumping (WP) and grain‐scale pumping (GP) components. Mechanistically, the dynamic pressure gradient best explains the HEF on both wave and grain scales. However, due to the underlying open‐channel flow, the result exhibits a phase lag compared to the theoretical WP, suggesting a necessary shift from the existing water surface‐based model to a pressure gradient‐based approach. Quantitatively, with the present experimental setting, the GP flux is 1 order of magnitude smaller than the WP flux. The relative significance of WP to GP is further increased at higher discharges, indicating potential utility of WP in habitat vitalization.
Disentangling the Impact of the COVID‐19 Lockdowns on Urban NO2 From Natural Variability
Authors: Goldberg Daniel L. , Anenberg Susan C. , Griffin Debora , McLinden Chris A. , Lu Zifeng , Streets David G.
Published: August 2020

TROPOMI satellite data show substantial drops in nitrogen dioxide (NO2) during COVID‐19 physical distancing. To attribute NO2 changes to NOx emissions changes over short timescales, one must account for meteorology. We find that meteorological patterns were especially favorable for low NO2 in much of the United States in spring 2020, complicating comparisons with spring 2019. Meteorological variations between years can cause column NO2 differences of ~15% over monthly timescales. After accounting for solar angle and meteorological considerations, we calculate that NO2 drops ranged between 9.2% and 43.4% among 20 cities in North America, with a median of 21.6%. Of the studied cities, largest NO2 drops (>30%) were in San Jose, Los Angeles, and Toronto, and smallest drops (<12%) were in Miami, Minneapolis, and Dallas. These normalized NO2 changes can be used to highlight locations with greater activity changes and better understand the sources contributing to adverse air quality in each city.
Toward Sustained Monitoring of Subsidence at the Coast Using InSAR and GPS: An Application in Hampton Roads, Virginia
Authors: Buzzanga Brett , Bekaert David P. S. , Hamlington Ben D. , Sangha Simran S.
Published: August 2020

Hampton Roads is among the regions along the U.S. Atlantic Coast experiencing high rates of relative sea level rise. Partly to mitigate subsidence from aquifer compaction, Hampton Roads is injecting treated wastewater into the underlying aquifer. However, the GPS (Global Positioning System) station spacing (∼30 km) is too coarse to capture the spatial variability of subsidence and potential uplift from the injection. We present a cost‐effective workflow for generating an InSAR (interferometric synthetic aperture radar) and GPS combined displacement product. We leverage a live, open‐access archive of InSAR products generated from Sentinel‐1 data. We find an overall subsidence rate of −3.6 ± 2.3 mm/year with considerable spatial variability. The effects of groundwater injection are currently below detection. The workflow presented here is an asset for sustained monitoring of the injection effort and regional subsidence that is applicable along the U.S. coasts for assisting in mitigation and adaptation of relative sea level rise.
Influence of Geochemical Features on the Mechanical Properties of Organic Matter in Shale
Authors: Zhao Junliang , Zhang Wei , Zhang Dongxiao , Wei Ren , Wang Yuhan
Published: August 2020

Organic matter is an important constituent in organic‐rich shale, which influences the hydrocarbon generation, as well as the mechanical behavior, of shale reservoirs. The physical, chemical, and mechanical properties of organic matter depend on the source material and the thermal evolution process. Previous works attempted to investigate the impact of thermal maturation on the mechanical properties of organic matter. However, owing to the lack of maceral classification and the limitation of data volume during the mechanical measurement, no consistent trend has been identified. In this work, vitrinite reflectance test, scanning electron microscope observation, nanoindentation, and micro‐Raman analysis were combined for geochemical and mechanical characterization. A total of 114 test areas were selected for testing, enhancing reliability of the test results. The Young's moduli of organic matter are from 3.57 to 8.32 GPa. With the same thermal maturity, inertinite has the highest Young's modulus, while the modulus of bitumen is the lowest. The Young's moduli of different organic types all increase with vitrinite reflectance. When vitrinite reflectance increases from 0.62% to 1.13%, the modulus of inertinite and vitrinite is increased by 57% and 78%, respectively. The indentation creep of different organic matter suggests that the stiffer organic type demonstrates less creep influence. In addition, with the increase of thermal maturity, the micro‐Raman test results show a decrease of intensity ratio of D peak to G peak, indicating an increase of the ordered structure in organic matter. From the characterization results, it was found that organic type and thermal maturity reflect the diversity of the source material and the chemical structure change during the thermal evolution process, and together they influence the mechanical properties of organic matter.
Predictability of Extreme Sea Level Variations Along the U.S. Coastline
Authors: Rashid M. M. , Wahl T.
Published: August 2020

Extreme sea level variability (excluding the effects of mean sea level (MSL) and long‐period tidal cycles) at decadal to multidecadal time scales is significant along the U.S. coastlines and can modulate coastal flood risk in addition to long‐term MSL rise. Therefore, understanding the climatic drivers and ultimately predicting these low‐frequency variations are important. Extreme sea level indicators are used to represent the variations in 100‐year return water levels, estimated with a nonstationary extreme value analysis. Here, we develop prediction models in the frequency domain. Extreme sea level indicators (response) and potential predictors (traditional climate indices, sea level pressure [SLP], or sea surface temperature [SST]) are decomposed into subseries corresponding to predefined frequencies using discrete wavelet transform (DWT), and regression models are formulated for each frequency separately. In the case of traditional climate indices, subseries of climate indices that provide the highest correlation with the corresponding subseries of indicators are used in the regression models, and original indicators are reconstructed by aggregating predicted subseries. Tailored climate indices are developed for each frequency band by averaging wavelet decomposed subseries of SLP or SST from grid locations where correlations with corresponding decomposed subseries of extreme sea level indicators are highest and robust. Models with wavelet filtered climate indices reproduce the variability and general trends of the indicators. The use of tailored indices further improves the model performance in predicting extreme sea level variations. Model performance in terms of Nash‐Sutcliffe efficiency statistics varies from 0.54 to 0.93. Prediction of extreme sea level indicators using tailored indices derived from SLP and SST of initialized decadal climate model simulations is also tested to facilitate progress toward forecasting extreme sea level variations at decadal time scales.
Inconsistent Atmosphere‐Ocean Dynamics and Multidecadal Zonal SST Gradient Trends Across the Equatorial Pacific Ocean in Reanalysis Products
Authors: Jayasankar T. , Murtugudde R. , Eldho T. I.
Published: August 2020

Ocean reanalysis products are routinely employed as reality checks in model evaluations and for process studies. This is especially so for critical regions such as the equatorial cold tongue (ECT) in the eastern equatorial Pacific where models suffer a chronic cold bias. ECT is a major player in the Pacific equatorial zonal sea surface temperature (SST) gradient (ΔEWSST) that has a significant impact on oceanic heat uptake and thus global climate. Hence, we investigate the reliability of three ocean reanalysis products for surface flux and ocean dynamic controls on ΔEWSST and Niño3.4 SST trends. We infer that while Niño3.4 SST trends are positive in all products, the signs of ΔEWSST trends do not agree with each other because initial conditions likely play a big role in their evolution. However, for ΔEWSST trends, the effect of initial conditions gets canceled out to some extent. Mixed layer heat budget and trends in ocean dynamic features such as tropical and subtropical cells, equatorial undercurrent, and subsurface temperatures are also diagnosed. We show that two reanalysis products that show a strengthening of ΔEWSST have contradicting trends in their surface heat flux and ocean dynamic contributions. This suggests that without accurate surface heat and momentum fluxes, data assimilation techniques may produce an east–west trend that is inconsistent among each other. Reanalysis products must address these issues considering the importance of this gradient.
Subglacial Discharge and Its Down‐Fjord Transformation in West Greenland Fjords With an Ice Mélange
Authors: Mortensen John , Rysgaard Søren , Bendtsen Jørgen , Lennert Kunuk , Kanzow Torsten , Lund Henrik , Meire Lorenz
Published: August 2020

Buoyant freshwater released at depth from under Greenland's marine‐terminating glaciers gives rise to vigorous buoyant discharge plumes adjacent to the termini. The water mass found down fjord formed by mixing of buoyant subglacial freshwater and ambient fjord water and subsequent modification by glacial ice melt in the ice mélange is referred to as subglacial water. It substantially affects both the physical and chemical properties of the fjords' marine environment. Despite the importance of this freshwater source, many uncertainties remain regarding its transformation and detection. Here we present observations close to a marine‐terminating glacier in a fjord with substantial ice mélange and follow the down‐fjord changes of the subglacial discharge plume. Heat brought to the surface by entrainment of warm ambient fjord water into the rising plume causes intense melting of the ice mélange close to the plume pool. This results in an increase of glacial ice melt fraction to total glacial meltwater from 1–2% in the plume pool to ~18% eleven kilometers down‐fjord, with the largest increase being observed within the first few kilometers. Down‐fjord of the ice mélange two temperature minima bound the layer containing subglacial water. The upper bound is linked to the adjacent ice mélange and down‐fjord runoff sources, whereas the lower bound is linked to the stratification of the ambient water. We show that similar bounds can be observed in other marine‐terminating glacier fjords along West Greenland that contain an ice mélange, suggesting that similar processes work in other fjords.
A New Approach for Estimating Salinity in the Southwest Atlantic and Its Application in a Data Assimilation Evaluation Experiment
Authors: Dorfschäfer G. S. , Tanajura C. A. S. , Costa F. B. , Santana R. C.
Published: August 2020

A new method for generating synthetic salinity (SS) profiles in the Southwest Atlantic was developed and applied in data assimilation experiments. This method was based on the smallest integrated values of root mean square deviation (RMSD)—with respect to observations—to infer salinity through climatological data and by regressive methods on temperature (T) using a five‐order polynomial function (P5). In the 14 delimited subregions, the averaged RMSD of P5 was 45% smaller than interpolated climatological data. However, climatological salinity presented better results in the first top layers while P5 presented smaller errors in higher depths. Therefore, by joining the best that P5 and climatology may offer, a new hybrid approach was used to generate SS based on T from XBT profiles. The SS would allow more T profiles to be employed in the Oceanographic Modeling and Observation Network (REMO) data assimilation system, called RODAS, into the Hybrid Coordinate Ocean Model (HYCOM). The use of SS estimates has potential to improve model outputs, in which the presence of the T‐S pair is quite necessary. Three integrations were performed: one run without assimilation (FREE), one assimilating sea surface temperature, Argo profilers, and sea level anomaly (RODAS) and one similar to RODAS, but with added XBTs with SS (RODAS_XBT). The inclusion of XBT data in the HYCOM + RODAS system improved the position and magnitude of the Brazil Current (BC). It was shown that SS is feasible for producing ocean reanalysis and initial conditions for ocean forecast systems requiring very low computational cost.
Temporal and Vertical Oxygen Gradients Modulate Nitrous Oxide Production in a Seasonally Anoxic Fjord: Saanich Inlet, British Columbia
Authors: Ji Qixing , Jameson Brett D. , Juniper S. Kim , Grundle Damian S.
Published: August 2020

Nitrous oxide (N2O) is a strong greenhouse gas and an ozone depleting agent. In marine environments, N2O is produced biologically via ammonium oxidation, nitrite, and nitrate reduction. The relative importance of these principle production pathways is strongly influenced by oxygen availability. We conducted 15N tracer experiments of N2O production in parallel with measurements of N2O concentration and natural abundance isotopes/isotopomers in Saanich Inlet, a seasonally anoxic fjord, to investigate how temporal and vertical oxygen gradients regulate N2O production pathways and rates. In April, June, and August 2018, the depth of the oxic‐anoxic interface (dissolved oxygen = 2.5 μmol L−1 isoline) progressively deepened from 110 to 160 m. Within the oxygenated and suboxic water column, N2O supersaturation coincided with peak ammonium oxidation activity. Conditions in the anoxic deep water were potentially favorable to N2O production from nitrate and nitrite reduction, but N2O undersaturation was observed indicating that N2O consumption exceeded rates of production. In October, tidal mixing introduced oxygenated water from outside the inlet, displacing the suboxic and anoxic deep water. This oxygenation event stimulated N2O production from ammonium oxidation and increased water column N2O supersaturation while inhibiting nitrate and nitrite reduction to N2O. Results from 15N tracer incubation experiments and natural abundance isotopomer measurements both implicated ammonium oxidation as the dominant N2O production pathway in Saanich Inlet, fueled by high ammonium fluxes (0.6–3.5 nmol m−2 s−1) from the anoxic depths. Partial denitrification contributed little to water column N2O production because of low availability of nitrate and nitrite.
Paleogeothermal Gradients Across an Inverted Hyperextended Rift System: Example of the Mauléon Fossil Rift (Western Pyrenees)
Authors: Saspiturry N. , Lahfid A. , Baudin T. , Guillou‐Frottier L. , Razin P. , Issautier B. , Le Bayon B. , Serrano O. , Lagabrielle Y. , Corre B.
Published: August 2020

The fossil rift in the North Pyrenean Zone, which underwent high temperature‐low pressure metamorphism and alkaline magmatism during Early Cretaceous hyperextension, was studied to explore the geothermal regime at the time of rifting. In this work, we combined Raman lab analysis and thermal numerical modelling to shed light on the distribution of geothermal gradients across the inverted hyperextended Mauléon rift basin during Albian and Cenomanian time, its period of active extension. Data were acquired from a set of 155 samples from densely spaced outcrops and boreholes, analyzed using Raman spectroscopy of carbonaceous material. The estimated paleogeothermal gradient is strongly related to the structural position along the Albian‐Cenomanian rift, increasing along a proximal‐distal margin transect from ~34°C/km in the European proximal margin to ~37–47°C/km in the two necking zones and 57–60°C/km in the hyperextended domain. This pattern of the paleogeothermal gradient induced a complex interaction between brittle and ductile deformation during crustal extension. A numerical model reproducing the thermal evolution of the North Pyrenees since 120 Ma suggests that mantle heat flow values may have reached 100 mW/m2 during the rifting event. This model reveals that above the thermal pulse, the temperature gradient varied within a small range of 55 to 62°C/km, as inferred from RSCM peak temperatures. We demonstrate that the style of reactivation during subsequent convergence influenced the thermal structure of the inverted rift system.
A Numerical Study of Slug Tests in a Three‐Dimensional Heterogeneous Porous Aquifer Considering Well Inertial Effects
Authors: Liu Quan , Hu Linwei , Bayer Peter , Xing Yixuan , Qiu Pengxiang , Ptak Thomas , Hu Rui
Published: August 2020

The slug test is a common field technique for obtaining local hydraulic parameters near wells, applied, for example, for the hydrogeological investigation at contaminated sites. Although many slug test models have been developed for interpretation of measurements, only a few of them have considered heterogeneous conditions, and water column inertial effects are usually neglected. In this paper, we propose a novel three‐dimensional slug test model (3DHIM) for application in heterogeneous aquifers, considering inertial effects associated with skin effects and linear friction forces. After comparison with existing analytical and numerical solutions of slug tests, the model is applied to an aquifer analog to simulate a series of slug tests. The results from single‐well slug tests show that the well geometry (i.e., the well radius, well depth, and screen length) has an impact on the water level response. For cross‐well slug tests, the results indicate that the water level fluctuations not only include information on the hydraulic signal propagation process in the aquifer but also on well characteristics, such as wellbore storage and inertial effects. These effects cause a phase shift and amplitude change of the water level fluctuation. As the observation and test wells have a good hydraulic connection and similar well geometry, the water level amplitude could be amplified relative to aquifer pressure at the measured position. Therefore, we suggest considering wellbore storage and in‐well inertial effects in slug test‐based subsurface investigations, otherwise the parameter estimates based on well water levels may include errors, particularly in highly permeable layers.
Global transcriptional downregulation of TREX and nuclear trafficking machinery as pan-senescence phenomena: evidence from human cells and tissues
Authors: Kim Sung Young , Yang Eun Jae , Lee Sung Bae , Lee Young-Sam , Cho Kyoung A. , Park Sang Chul
Published: August 2020

Nucleocytoplasmic trafficking (NCT) of macromolecules is a fundamental process in eukaryotes that requires tight controls to maintain proper cell functions. Downregulation of the classical NCT pathway in senescent cells has been reported. However, whether this is a hallmark that exists across all types of cellular senescence remains unknown, and whether the mRNA export machinery is altered during senescence has not been demonstrated. Here, we show that the global transcriptomic downregulation of both the TREX (transcription-export) machinery and classical NLS-dependent protein transport machinery is a hallmark of varying types of senescence. A gene set-based approach using 25 different studies showed that the TREX-NCT gene set displays distinct common downregulated patterns in senescent cells versus its expression in their nonsenescent counterparts regardless of the senescence type, such as replicative senescence (RS), tumor cell senescence (TCS), oncogene-induced senescence (OIS), stem cell senescence (SCS), progeria and endothelial cell senescence (ECS). Similar patterns of TREX-NCT gene downregulation were also shown in two large human tissue genomic databases, the Genotype-Tissue Expression (GTEx) and The Cancer Genome Atlas (TCGA) databases. We also found that early-stage cancer tissues show consistent age-related patterns of TREX-NCT enrichment, suggesting the potential significance of TREX-NCT genes in determining cell fate in the early stage of tumorigenesis. Moreover, human cancer tissues exhibit an opposite TREX-NCT enrichment pattern with aging, indicating that deviation from age-related changes in TREX-NCT genes may provide a novel but critical clue for the age-dependent pathogenesis of cancer and increase in cancer incidence with aging.
Evaluation-oriented exploration of photo energy conversion systems: from fundamental optoelectronics and material screening to the combination with data science
Authors: Saeki Akinori
Published: August 2020

Light is a form of energy that can be converted to electric and chemical energies. Thus, organic photovoltaics (OPVs), perovskite solar cells (PSCs), photocatalysts, and photodetectors have evolved as scientific and commercial enterprises. However, the complex photochemical reactions and multicomponent materials involved in these systems have hampered rapid progress in their fundamental understanding and material design. This review showcases the evaluation-oriented exploration of photo energy conversion materials by using electrodeless time-resolved microwave conductivity (TRMC) and materials informatics (MI). TRMC with its unique options (excitation sources, environmental control, frequency modulation, etc.) provides not only accelerated experimental screening of OPV and PSC materials but also a versatile route toward shedding light on their charge carrier dynamics. Furthermore, MI powered by machine learning is shown to allow extremely high-throughput exploration in the large molecular space, which is compatible with experimental screening and combinatorial synthesis.
Cell-surface receptors enable perception of extracellular cytokinins
Authors: Antoniadi Ioanna , Novák Ondřej , Gelová Zuzana , Johnson Alexander , Plíhal Ondřej , Simerský Radim , Mik Václav , Vain Thomas , Mateo-Bonmatí Eduardo , Karady Michal , Pernisová Markéta , Plačková Lenka , Opassathian Korawit , Hejátko Jan , Robert Stéphanie , Friml Jiří , Doležal Karel , Ljung Karin , Turnbull Colin
Published: August 2020

Cytokinins are mobile multifunctional plant hormones with roles in development and stress resilience. Although their Histidine Kinase receptors are substantially localised to the endoplasmic reticulum, cellular sites of cytokinin perception and importance of spatially heterogeneous cytokinin distribution continue to be debated. Here we show that cytokinin perception by plasma membrane receptors is an effective additional path for cytokinin response. Readout from a Two Component Signalling cytokinin-specific reporter (TCSn::GFP) closely matches intracellular cytokinin content in roots, yet we also find cytokinins in extracellular fluid, potentially enabling action at the cell surface. Cytokinins covalently linked to beads that could not pass the plasma membrane increased expression of both TCSn::GFP and Cytokinin Response Factors. Super-resolution microscopy of GFP-labelled receptors and diminished TCSn::GFP response to immobilised cytokinins in cytokinin receptor mutants, further indicate that receptors can function at the cell surface. We argue that dual intracellular and surface locations may augment flexibility of cytokinin responses.
Excess-entropy scaling in supercooled binary mixtures
Authors: Bell Ian H. , Dyre Jeppe C. , Ingebrigtsen Trond S.
Published: August 2020

Transport coefficients, such as viscosity or diffusion coefficient, show significant dependence on density or temperature near the glass transition. Although several theories have been proposed for explaining this dynamical slowdown, the origin remains to date elusive. We apply here an excess-entropy scaling strategy using molecular dynamics computer simulations and find a quasiuniversal, almost composition-independent, relation for binary mixtures, extending eight orders of magnitude in viscosity or diffusion coefficient. Metallic alloys are also well captured by this relation. The excess-entropy scaling predicts a quasiuniversal breakdown of the Stokes-Einstein relation between viscosity and diffusion coefficient in the supercooled regime. Additionally, we find evidence that quasiuniversality extends beyond binary mixtures, and that the origin is difficult to explain using existing arguments for single-component quasiuniversality.
High-performance p-channel transistors with transparent Zn doped-CuI
Authors: Liu Ao , Zhu Huihui , Park Won-Tae , Kim Se-Jun , Kim Hyungjun , Kim Myung-Gil , Noh Yong-Young
Published: August 2020

‘Ideal’ transparent p-type semiconductors are required for the integration of high-performance thin-film transistors (TFTs) and circuits. Although CuI has recently attracted attention owing to its excellent opto-electrical properties, solution processability, and low-temperature synthesis, the uncontrolled copper vacancy generation and subsequent excessive hole doping hinder its use as a semiconductor material in TFT devices. In this study, we propose a doping approach through soft chemical solution process and transparent p-type Zn-doped CuI semiconductor for high-performance TFTs and circuits. The optimised TFTs annealed at 80 °C exhibit a high hole mobility of over 5 cm2 V−1 s−1 and high on/off current ratio of ~107 with good operational stability and reproducibility. The CuI:Zn semiconductors show intrinsic advantages for next-generation TFT applications and wider applications in optoelectronics and energy conversion/storage devices. This study paves the way for the realisation of transparent, flexible, and large-area integrated circuits combined with n-type metal-oxide semiconductor.
Multi-site clonality analysis uncovers pervasive heterogeneity across melanoma metastases
Authors: Rabbie Roy , Ansari-Pour Naser , Cast Oliver , Lau Doreen , Scott Francis , Welsh Sarah J. , Parkinson Christine , Khoja Leila , Moore Luiza , Tullett Mark , Wong Kim , Ferreira Ingrid , Gómez Julia M. Martínez , Levesque Mitchell , Gallagher Ferdia A. , Jiménez-Sánchez Alejandro , Riva Laura , Miller Martin L. , Allinson Kieren , Campbell Peter J. , Corrie Pippa , Wedge David C. , Adams David J.
Published: August 2020

Metastatic melanoma carries a poor prognosis despite modern systemic therapies. Understanding the evolution of the disease could help inform patient management. Through whole-genome sequencing of 13 melanoma metastases sampled at autopsy from a treatment naïve patient and by leveraging the analytical power of multi-sample analyses, we reveal evidence of diversification among metastatic lineages. UV-induced mutations dominate the trunk, whereas APOBEC-associated mutations are found in the branches of the evolutionary tree. Multi-sample analyses from a further seven patients confirmed that lineage diversification was pervasive, representing an important mode of melanoma dissemination. Our analyses demonstrate that joint analysis of cancer cell fraction estimates across multiple metastases can uncover previously unrecognised levels of tumour heterogeneity and highlight the limitations of inferring heterogeneity from a single biopsy.
Feline coronavirus drug inhibits the main protease of SARS-CoV-2 and blocks virus replication
Authors: Vuong Wayne , Khan Muhammad Bashir , Fischer Conrad , Arutyunova Elena , Lamer Tess , Shields Justin , Saffran Holly A. , McKay Ryan T. , van Belkum Marco J. , Joyce Michael A. , Young Howard S. , Tyrrell D. Lorne , Vederas John C. , Lemieux M. Joanne
Published: August 2020

The main protease, Mpro(or 3CLpro) in SARS-CoV-2 is a viable drug target because of its essential role in the cleavage of the virus polypeptide. Feline infectious peritonitis, a fatal coronavirus infection in cats, was successfully treated previously with a prodrug GC376, a dipeptide-based protease inhibitor. Here, we show the prodrug and its parent GC373, are effective inhibitors of the Mprofrom both SARS-CoV and SARS-CoV-2 with IC50values in the nanomolar range. Crystal structures of SARS-CoV-2 Mprowith these inhibitors have a covalent modification of the nucleophilic Cys145. NMR analysis reveals that inhibition proceeds via reversible formation of a hemithioacetal. GC373 and GC376 are potent inhibitors of SARS-CoV-2 replication in cell culture. They are strong drug candidates for the treatment of human coronavirus infections because they have already been successful in animals. The work here lays the framework for their use in human trials for the treatment of COVID-19.
Copper(I)-catalyzed diastereo- and enantio-selective construction of optically pure exocyclic allenes
Authors: He Cheng-Yu , Tan Yun-Xuan , Wang Xin , Ding Rui , Wang Yi-Fan , Wang Feng , Gao Dingding , Tian Ping , Lin Guo-Qiang
Published: August 2020

Among about 150 identified allenic natural products, the exocyclic allenes constitute a major subclass. Substantial efforts are devoted to the construction of axially chiral allenes, however, the strategies to prepare chiral exocyclic allenes are still rare. Herein, we show an efficient strategy for the asymmetric synthesis of chiral exocyclic allenes with the simultaneous control of axial and central chirality through copper(I)-catalyzed asymmetric intramolecular reductive coupling of 1,3-enynes to cyclohexadienones. This tandem reaction exhibits good functional group compatibility and the corresponding optically pure exocyclic allenes bearing cis-hydrobenzofuran, cis-hydroindole, and cis-hydroindene frameworks, are obtained with high yields (up to 99% yield), excellent diastereoselectivities (generally >20:1 dr) and enantioselectivities (mostly >99% ee). Furthermore, a gram-scale experiment and several synthetic transformations of the chiral exocyclic allenes are also presented.
Single-molecule photoreaction quantitation through intraparticle-surface energy transfer (i-SET) spectroscopy
Authors: Zhou Jian , Li Changyu , Li Denghao , Liu Xiaofeng , Mu Zhao , Gao Weibo , Qiu Jianrong , Deng Renren
Published: August 2020

Quantification of nanoparticle-molecule interaction at a single-molecule level remains a daunting challenge, mainly due to ultra-weak emission from single molecules and the perturbation of the local environment. Here we report the rational design of an intraparticle-surface energy transfer (i-SET) process, analogous to high doping concentration-induced surface quenching effects, to realize single-molecule sensing by nanoparticle probes. This design, based on a Tb3+-activator-rich core-shell upconversion nanoparticle, enables a much-improved spectral response to fluorescent molecules at single-molecule levels through enhanced non-radiative energy transfer with a rate over an order of magnitude faster than conventional counterparts. We demonstrate a quantitative analysis of spectral changes of one to four fluorophores tethered on a single nanoparticle through i-SET spectroscopy. Our results provide opportunities to identify photoreaction kinetics at single-molecule levels and provide direct information for understanding behaviors of individual molecules with unprecedented sensitivity.
Complete reversal of the atomic unquenched orbital moment by a single electron
Authors: Rejali Rasa , Coffey David , Gobeil Jeremie , González Jhon W. , Delgado Fernando , Otte Alexander F.
Published: August 2020

The orbital angular moment of magnetic atoms adsorbed on surfaces is often quenched as a result of an anisotropic crystal field. Due to spin-orbit coupling, what remains of the orbital moment typically delineates the orientation of the electron spin. These two effects limit the scope of information processing based on these atoms to essentially only one magnetic degree of freedom: the spin. In this work, we gain independent access to both the spin and orbital degrees of freedom of a single atom, inciting and probing excitations of each moment. By coordinating a single Fe atom atop the nitrogen site of the Cu2N lattice, we realize a single-atom system with a large zero-field splitting—the largest reported for Fe atoms on surfaces—and an unquenched uniaxial orbital moment that closely approaches the free-atom value. We demonstrate a full reversal of the orbital moment through a single-electron tunneling event between the tip and Fe atom, a process that is mediated by a charged virtual state and leaves the spin unchanged. These results, which we corroborate using density functional theory and first-principles multiplet calculations, demonstrate independent control over the spin and orbital degrees of freedom in a single-atom system.
Author Correction: Benchmark maps of 33 years of secondary forest age for Brazil
Authors: Silva Junior Celso H. L. , Heinrich Viola H. A. , Freire Ana T. G. , Broggio Igor S. , Rosan Thais M. , Doblas Juan , Anderson Liana O. , Rousseau Guillaume X. , Shimabukuro Yosio E. , Silva Carlos A. , House Joanna I. , Aragão Luiz E. O. C.
Published: August 2020

An amendment to this paper has been published and can be accessed via a link at the top of the paper.