bluuebunny/crossref_metadata_2025 huggingface dataset:
Edge-enriched MoS2 for kinetics-enhanced potassium storage
Authors: Jiang Guangshen , Xu Xiaosa , Han Haojie , Qu Changzhen , Repich Hlib , Xu Fei , Wang Hongqiang
Published: July 2020

Potassium-ion batteries (PIBs) hold great promise as alternatives to lithium ion batteries in post-lithium age, while face challenges of slow reaction kinetics induced by the inherent characteristics of large-size K+. We herein show that creating sufficient exposed edges in MoS2 via constructing ordered mesoporous architecture greatly favors for improved kinetics as well as increased reactive sites for K storage. The engineered MoS2 with edge-enriched planes (EE-MoS2) is featured by three-dimensional bicontinuous frameworks with ordered mesopores of ~ 5.0 nm surrounded by thin wall of ~9.0 nm. Importantly, EE-MoS2 permits exposure of enormous edge planes at pore walls, renders its intrinsic layer spacing more accessible for K+ and accelerates conversion kinetics, thus realizing enhanced capacity and high rate capability. Impressively, EE-MoS2 displays a high reversible charge capacity of 506 mAh·g−1 at 0.05 A·g−1, superior cycling capacities of 321 mAh·g−1 at 1.0 A·g−1 after 200 cycles and a capacity of 250 mAh·g−1 at 2.0 A·g−1, outperforming edge-deficient MoS2 with nonporous bulk structure. This work enlightens the nanoarchitecture design with abundant edges for improving electrochemical properties and provides a paradigm for exploring high-performance PIBs.
Sozialpädagogik als disziplinäre Grenzgänger*in
Authors: Hünersdorf Bettina
Published: July 2020

Sozialpädagogik als disziplinäre Grenzgänger*in nimmt die disziplinäre Form der Sozialpädagogik in den Anfängen ihrer Versozialwissenschaftlichung in den Blick. Dabei wird eine Lesart von Aloys Fischers Sozialpädagogik entwickelt, die mit ihm und über ihn hinaus gehend die These begründet, dass die Sozialpädagogik sich durch eine doppelte Offenheit kennzeichne: zum einen die Offenheit gegenüber anderen sozialwissenschaftlichen Disziplinen wie der Soziologie und der Psychologie, welche zur interdisziplinären Konstitution der Sozialpädagogik beitrage, zum anderen die Offenheit gegenüber der professionellen Praxis. Erst durch diese doppelt miteinander verschränkte Relationierung der Sozialpädagogik ergibt sich ihre spezifische, sich gegenüber anderen Sozialwissenschaften unterscheidende Gestalt. Mit der ‚deskriptiven‘ Sozialpädagogik gibt es Anknüpfungspunkte für eine erkenntnistheoretische und methodologische Grundlegung, die durch sinnliche Erkenntnisbildung vermag zwischen einer sozialwissenschaftlich generierten Theorie der Sozialpädagogik und einer professionellen Praxis der Sozialpädagogik zu vermitteln. Dadurch bekommt die Sozialpädagogik als Disziplin eine performative (zukunfts-)offene Form, in welcher der Bruch zwischen sozialpädagogischer Theorie und professioneller Praxis nicht als Problem, sondern als Möglichkeit wahrgenommen wird, sich (un-)abhängig voneinander zu konstituieren.
Preschool Teachers’ Perspectives About the Engagement of Immigrant and Non-Immigrant Parents in Their Children’s Early Education
Authors: Kurucz Csaba , Lehrl Simone , Anders Yvonne
Published: July 2020

The present study explores the perceptions of teachers about the engagement of immigrant and non-immigrant parents in preschool. Data were drawn from a larger evaluation study of a government initiative for preschools in Germany, which was designed to foster inclusive pedagogy and parent cooperation. In these analyses, teachers’ perceptions of the engagement of immigrant parents and non-immigrant parents were rated for each parent group, on a 10-item measure, to identify how teacher ratings varied for the different parent groups. Data from 1397 preschool teachers, employed across 203 preschools, were analyzed using multilevel modeling. This statistical approach takes account of the clustered nature of the data. Teacher ratings of engagement for immigrant and non-immigrant parent groups differed between preschools. Most variability in the ratings could be ascribed to preschool characteristics. In preschools, in which staff held a shared understanding of dealing with cultural diversity and in which the director of the preschool had a multicultural mindset, teachers perceived engagement of parents more positively, especially for immigrant parents. Overall, the findings identified the importance of self-efficacy for inclusion and more positive beliefs about multiculturalism among preschool teachers. Such qualities are important for working with all parents. However, unfavorable social structures, such as those found in disadvantaged areas, may present major challenges for parent cooperation and engagement.
Bi-FoRe: an efficient bidirectional knockin strategy to generate pairwise conditional alleles with fluorescent indicators
Authors: Han Bingzhou , Zhang Yage , Bi Xuetong , Zhou Yang , Krueger Christopher J. , Hu Xinli , Zhu Zuoyan , Tong Xiangjun , Zhang Bo
Published: July 2020

Gene expression labeling and conditional manipulation of gene function are important for elaborate dissection of gene function. However, contemporary generation of pairwise dual-function knockin alleles to achieve both conditional and geno-tagging effects with a single donor has not been reported. Here we first developed a strategy based on a flipping donor named FoRe to generate conditional knockout alleles coupled with fluorescent allele-labeling through NHEJ-mediated unidirectional targeted insertion in zebrafish facilitated by the CRISPR/Cas system. We demonstrated the feasibility of this strategy at sox10 and isl1 loci, and successfully achieved Cre-induced conditional knockout of target gene function and simultaneous switch of the fluorescent reporter, allowing generation of genetic mosaics for lineage tracing. We then improved the donor design enabling efficient one-step bidirectional knockin to generate paired positive and negative conditional alleles, both tagged with two different fluorescent reporters. By introducing Cre recombinase, these alleles could be used to achieve both conditional knockout and conditional gene restoration in parallel; furthermore, differential fluorescent labeling of the positive and negative alleles enables simple, early and efficient real-time discrimination of individual live embryos bearing different genotypes prior to the emergence of morphologically visible phenotypes. We named our improved donor as Bi-FoRe and demonstrated its feasibility at the sox10 locus. Furthermore, we eliminated the undesirable bacterial backbone in the donor using minicircle DNA technology. Our system could easily be expanded for other applications or to other organisms, and coupling fluorescent labeling of gene expression and conditional manipulation of gene function will provide unique opportunities to fully reveal the power of emerging single-cell sequencing technologies.
Promoting Clean Energy Innovation at the State and Local Level
Authors: Popp David
Published: July 2020

Innovation is an important part of energy policy, and encouraging clean energy innovation is often an explicit goal of policy makers. For local governments, promoting clean energy innovation is seen not only as a pathway to a cleaner economy but also as a tool for promoting the local economy. But is such optimism warranted? There is a substantial literature examining the relationships between innovation and environmental policy, but few studies focus explicitly on innovation at the state and local level. In this paper, I provide key lessons from research on clean energy innovation, focusing on lessons relevant for state and local governments. I then summarize the results of a recent working paper by Fu et al. (2018) that studied wind energy innovation across individual states in the United States. While state-level policies can promote clean energy innovation, it is overall market size that matters most. Thus, innovation need not occur in those states most actively promoting clean energy. I conclude with lessons for state and local governments drawn from both this work and the broader literature on energy innovation.
Asylum Courts, Transnational Petitioning, and Digital Dispersal in Africa
Authors: Lawrance Benjamin N. , Corcoran Erin B. , Hooper Louise
Published: July 2020

Asylum court records are a potentially important evidentiary basis for postcolonial African history. Asylum-seeking is a contemporary transnational iteration of a rich African petitioning tradition. In the contemporary era, the digitization of court records, and their dispersal as a function of the shifting division of work between ministries, courts, and related bureaucracies, presents a challenge to researchers. Digital record keeping may improve accessibility, but only if researchers are familiar with the technology and archival methods and practices accompanying digitization.
Modelling dynamic ice-sheet boundaries and grounding line migration using the level set method
Authors: Hossain M. Alamgir , Pimentel Sam , Stockie John M.
Published: July 2020

Computing predictions of future sea level that include well-defined uncertainty bounds requires models that are capable of robustly simulating the evolution of ice sheets and glaciers. Ice flow behaviour is known to be sensitive to the location and geometry of dynamic ice boundaries such as the grounding line (GRL), terminus position and ice surface elevation, so that any such model should track these interfaces with a high degree of accuracy. To address this challenge, we implement a numerical approach that uses the level-set method (LSM) that accurately models the evolution of the ice–air and ice–water interface as well as capturing topological changes in ice-sheet geometry. This approach is evaluated by comparing simulations of grounded and marine-terminating ice sheets to various analytical and numerical benchmark solutions. A particular advantage of the LSM is its ability to explicitly track the moving margin and GRL while using a fixed grid finite-difference scheme. Our results demonstrate that the LSM is an accurate and robust approach for tracking the ice surface interface and terminus for advancing and retreating ice sheets, including the transient marine ice-sheet interface and GRL positions.
The National Growth of a Regional Party: Evidence of Linkages between Constituency Associations in the Conservative Party of Canada
Authors: Currie-Wood Rob
Published: July 2020

Reforms to campaign finance laws at the beginning of the twenty-first century led to concerns that Canadian political parties would become more centralized, thereby altering the stratarchical arrangement between local party organizations and the national party office. This article extends the period of analysis to 2008 and 2011. Although concerns were not unfounded, data reported in this article reveal that horizontal linkages developed between constituency associations in the Conservative Party of Canada, instead of downward money transfers from the national office. The article compares the Conservative party to its major competitors and explores three regional cases where these linkages are prevalent. Tobit regression is used to examine whether monetary transfers are coordinated by the central office or initiated by local constituency associations. Given weak evidence for the latter, the findings demonstrate that parties with a reliable base of support can leverage their campaign resources from one region into a national presence.
Maize relay intercropping with fodder crops for small-scale farmers in central Brazil
Authors: Baldé Alpha Bocar , Scopel Eric , Affholder François , Da Silva Fernando Antonio Macena , Wery Jacques , Corbeels Marc
Published: July 2020

Relay intercropping of maize with fodder crops is a promising option for sustainable intensification of dairy small-scale farms in the Cerrado of Brazil. Twenty-six intercropping trials were conducted on farmers’ fields with the following experimental treatments: sole maize crop cropping (MS), maize-Brachiaria intercropping (MB) and maize-pigeon pea intercropping (MP). The trials were managed by the farmers, i.e. choice of conventional tillage (CT) versus no-tillage (NT), sowing dates, fertilization and weed control. Maize grain yield varied strongly across the farmer fields, from 100 to 5900 kg ha−1 in the MS treatment, 500 to 6900 kg ha−1 in MP and 300 to 5500 kg ha−1 in MB. Intercropping did not significantly affect maize grain yields under NT, but yields were reduced under CT in one out of two seasons. Maize yields in the intercropped systems were also higher under NT than CT. Total biomass productivity was significantly higher in the maize-fodder than in the sole maize system. An increased interval between sowing of maize and fodder crop significantly reduced the fodder crop biomass. Relay intercropping, especially in combination with NT, is a promising option if crop calendars and fertilization are properly managed by farmers to reduce interspecific competition between the maize and fodder crop.
Reproducibility and external validity of on-farm experimental research in Africa
Authors: Kool Hanna , Andersson Jens A. , Giller Ken E.
Published: July 2020

Agronomists have increasingly conducted experiments on-farm, in an attempt to increase the wider applicability (external validity) of their experimental findings and their relevance for agricultural development. This review assesses the way in which on-farm experimental studies address the scope or generalisability of their findings when based on a limited number of farms. A central question is how on-farm studies define the environment or research population in which the on-farm trial findings are valid, or are valuable for. Such an assessment is, of course, conditional on the (internal) validity of the experimental findings. We therefore first analyse how authors of on-farm experimental studies describe the factors that may shape experimental outcomes. As agronomic experiments often use ‘yield’ as dependent variable to assess treatment effects, we developed a procedure to score studies on their descriptions of yield-determining factors. Although experimental validity principally rests upon the reproducibility of the experiment and its findings, we found that on the basis of the information provided in published on-farm experimental studies, it is often difficult or impossible to reproduce the experimental design. Nutrient management, weed management and crop information are best described, whereas land preparation, field history and management of pests and water are rarely described. Further, on-farm experimental studies often compare treatments to a ‘farmer practice’ reference or control treatment which is assumed to be widely and uniformly practiced and known to the reader. The wider applicability or external validity is often poorly addressed in the reviewed studies. Most do not explicitly define the research population and/or environment in which (they expect) the experimental findings to work. Academic textbooks on agronomic experimentation are remarkably silent on both the internal and external validity of on-farm experimentation. We therefore argue for more systematic investigations and descriptions of the research population and settings to which on-farm experimental studies seek to generalise their findings.
Age, Education and Intellectual Quotient Influences: Structural Equation Modeling on the study of Benton Visual Retention Test (BVRT)
Authors: Segabinazi Joice Dickel , Pawlowski Josiane , Zanini Adriana Mokwa , Wagner Gabriela Peretti , Sbicigo Juliana Burges , Trentini Clarissa Marceli , Hutz Claudio Simon , de Salles Jerusa Fumagalli , Bandeira Denise Ruschel
Published: July 2020

This study searched for sociodemographic influences on visual memory and visuoconstructive ability in healthy and clinical samples evaluated with Benton Visual Retention Test (BVRT) in two studies. In Study 1, we searched for changes related to age in children, adolescents, adults and elderly on the performance of the BVRT. In Study 2, we investigated the relations among age, years of education and intellectual quotient (IQ) on the performance of the BVRT using Structural Equation Modeling (SEM). Participants were 624 individuals aged between six and 89 years old (M = 25.40; SD = 22.34) from the normatization and evidence validity studies at Brazil. We used a sociodemographic questionnaire, BVRT and IQ measure was estimated. Study 1 has shown a performance similar to the developmental graphics with a U-inverted pattern in relation to age: An increase of the visual memory ability in the children and adolescent groups as age increases, a tendency of a decrease in the performance in the adult group that intensifies in the elderly group. Study 2 found that the model for the BVRT performance tested by SEM denoted satisfactory goodness-of-fit indexes, χ2/gl = 2.67, p < .001; CFI = .92; TLI = .93; RMSEA = .004, 90% CI = [.03, .05];WLSMV = 1.79, and corroborated the theoretical assumption. The SEM model confirmed in this study highlight the strong role of years of education in the prediction of BVRT scores.
Demand for Ports to 2050: Climate Policy, Growing Trade and the Impacts of Sea‐Level Rise
Authors: Hanson Susan E. , Nicholls Robert J.
Published: July 2020

Port infrastructure is critical to the world's economy and has seen major expansion over the last few decades. In the future there are likely to be further demands for port capacity which will require additional port area while existing ports will need upgrading in response to sea‐level rise to maintain current levels of operability. This analysis considers potential changes to 2050 under four climate‐based scenarios which aim to explore changes in international maritime trade consistent with global temperature increases of 2 °C and 4 °C and the implications of associated sea‐level rise. All scenarios anticipate a significant increase in trade, and a change in distribution across commodities. The demand for port handling areas in 2050 is roughly double to quadruple that of the baseline (2010) across scenarios. The maximum demand occurs under an unmitigated climate and high intensity in commodity movement with a maximum area in 2050 of 5,054km2. The minimum demand (2,510km2) occurs under a scenario of regionalized green energy production and lower material intensity. The total global investment costs for port adaptation to sea‐level rise and provision of new areas are between 223 and 768 billion USD to 2050. These are dominated by the need for new area construction with the adaptation of base year areas to relative sea‐level rise representing a maximum of 6% of total costs globally. Therefore, in addition to adapting existing port areas to sea‐level rise, it is equally or more important to consider provision of new ports.
Enlarging Regional Disparities in Energy Intensity within China
Authors: Shao Shuai , Wang Chang , Guo Yue , Yang Lili , Chen Shiyi , Yan Jinyue , Shan Yuli , Liu Zhu , Guan Dabo
Published: July 2020

As energy saving and emission reduction become a global action, the disparity in energy intensity between different regions is a new rising problem that stems a country's or region's energy‐saving potential. Here we collect China's provincial panel data (1995–2017) of primary and final energy consumption to evaluate China's unequal and polarized regional pattern in energy intensity, decompose the inequality index into contributing components, and investigate possible driving factors behind the unequal pattern both regionally and structurally, for the first time. The results show that China's interprovince disparities in energy intensity increase and are exacerbated by the enlarging disparities in energy intensity between the least developed and most developed regions of China. The causes for this phenomenon are as follows: (i) rather loose regulatory measures on mitigating coal consumption; (ii) inferior energy processing technology in areas specializing in energy‐intensive industries; (iii) increasing interregional energy fluxes embodied in trade; and (iv) separate jurisdictions at provincial administrative levels. These factors can synthetically result in unintended spillover to areas with inferior green technologies, suggesting an increasingly uneven distribution of energy‐intensive and carbon‐intensive industries and usage of clean energy. The results reveal the necessities of regional coordination and cooperation to achieve a green economy.
Influence of Lithology on Reactive Melt Flow Channelization
Authors: Pec M. , Holtzman B. K. , Zimmerman M. E. , Kohlstedt D. L.
Published: July 2020

To investigate channelization during migration of a reactive melt, we performed a series of Darcy‐type experiments in which an alkali basalt infiltrated partially molten harzburgites and lherzolites at a confining pressure of 300 MPa, temperatures of 1200°C and 1250°C, and pore pressure gradients of ~2 to 60 MPa/mm. We compare our results to those from previously published experiments performed on wehrlites. In all experiments, irrespective of the exact mineralogy, a planar reaction layer composed of olivine + melt developed in which all of the pyroxene was consumed. Under specific conditions controlled primarily by the melt flow velocity, finger‐like channels composed of olivine + melt also developed. In wehrlites, these reaction infiltration instabilities formed at 1200°C and 1250°C at pressure gradients >25 and >5 MPa/mm, respectively. In harzburgites, channelization occurred only at 1250°C at a pressure gradient of 35 MPa/mm. In lherzolites, a planar melt‐filled vein developed at 1250°C; no finger‐like channels formed under a pressure gradient of ~25 MPa/mm. Both the finger‐like channels and the planar vein led to very efficient extraction of melt from the reservoir. Channelization established large compositional variations over short distances in the crystalized phases as well as in the local melt and greatly enhanced the abundance of the reaction product, olivine, similar to dunite channels in the Earth. The range of chemical‐mechanical responses displayed by this array of compositions provides a set of targets for reactive transport and mechanical modeling studies.
Reactivating and Calming Volcanoes: The 2015 MW 8.3 Illapel Megathrust Strike
Authors: Farías Cristian , Basualto Daniel
Published: July 2020

The 2015 MW 8.3 Illapel earthquake was followed in a time frame of weeks to months by very different responses from Nevados de Chillán, Copahue, and Villarrica volcanoes, all located more than 580 km from the rupture zone. Here we show how Nevados de Chillán and Copahue started new eruptive phases, and Villarrica entered in a period of relative calm. Using seismic, geodetic, and geochemical observations, in combination with numerical wave propagation simulations, we also show that the geometry of the fault system controlled the impact of the earthquake on each volcano. We argue that the sensitivity of a volcano toward an earthquake depends on both its critical state before the mainshock and the geometry of its fault system. This is a case where the same earthquake generates very different responses at the same time, at large distances, rendering volcanoes as very sensitive systems.
Polygonal Eyewall Asymmetries During the Rapid Intensification of Hurricane Michael (2018)
Authors: Cha Ting‐Yu , Bell Michael M. , Lee Wen‐Chau , DesRosiers Alexander J.
Published: July 2020

Polygonal eyewall asymmetries of Hurricane Michael (2018) during rapid intensification (RI) are analyzed from ground‐based single Doppler radar. Here, we present the first observational evidence of the evolving wind field of a polygonal eyewall during RI to Category 5 intensity by deducing the axisymmetric and asymmetric winds at 5‐min intervals. Spectral time decomposition of the retrieved tangential wind structure shows quantitative evidence of low (1–4) azimuthal wavenumbers with propagation speeds that are consistent with linear wave theory on a radial vorticity gradient, suggesting the presence of rapidly evolving vortex Rossby waves. Dual‐Doppler winds from the NOAA P‐3 Hurricane Hunter airborne radar provide further evidence of the three‐dimensional vortex structure that supports growth of asymmetries during RI. Both reflectivity and tangential wind fields show polygonal structure and propagate at similar speeds, suggesting a close coupling of the dynamics and the convective organization during the intensification.
Turbidity Hysteresis in an Estuary and Tidal River Following an Extreme Discharge Event
Authors: Ralston David K. , Yellen Brian , Woodruff Jonathan D. , Fernald Sarah
Published: July 2020

Nonlinear turbidity‐discharge relationships are explored in the context of sediment sourcing and event‐driven hysteresis using long‐term (≥12‐year) turbidity observations from the tidal freshwater and saline estuary of the Hudson River. At four locations spanning 175 km, turbidity generally increased with discharge but did not follow a constant log‐log dependence, in part due to event‐driven adjustments in sediment availability. Following major sediment inputs from extreme precipitation and discharge events in 2011, turbidity in the tidal river increased by 20–50% for a given discharge. The coherent shifts in the turbidity‐discharge relationship along the tidal river over the subsequent 2 years suggest that the 2011 events increased sediment availability for resuspension. In the saline estuary, changes in the sediment‐discharge relationship were less apparent after the high discharge events, indicating that greater background turbidity due to internal sources make event‐driven inputs less important in the saline estuary at interannual time scales.
Subsurface Weathering Revealed in Hillslope‐Integrated Porosity Distributions
Authors: Callahan Russell P. , Riebe Clifford S. , Pasquet Sylvain , Ferrier Ken L. , Grana Dario , Sklar Leonard S. , Taylor Nicholas J. , Flinchum Brady A. , Hayes Jorden L. , Carr Bradley J. , Hartsough Peter C. , O'Geen Anthony T. , Holbrook W. Steven
Published: July 2020

Subsurface weathering has traditionally been measured using cores and boreholes to quantify vertical variations in weathered material properties. However, these measurements are typically available at only a few, potentially unrepresentative points on hillslopes. Geophysical surveys, conversely, span many more points and, as shown here, can be used to obtain a representative, site‐integrated perspective on subsurface weathering. Our approach aggregates data from multiple seismic refraction surveys into a single frequency distribution of porosity and depth for the surveyed area. We calibrated the porosities at a site where cores are coincident with seismic refraction surveys. Modeled porosities from the survey data match measurements at the core locations but reveal a frequency distribution of porosity and depth that differs markedly from the cores. Our results highlight the value of using the site‐integrated perspective obtained from the geophysical data to quantify subsurface weathering and water‐holding capacity.
High‐Spatiotemporal Resolution Observations of Jupiter Lightning‐Induced Radio Pulses Associated With Sferics and Thunderstorms
Authors: Imai Masafumi , Wong Michael H. , Kolmašová Ivana , Brown Shannon T. , Santolík Ondřej , Kurth William S. , Hospodarsky George B. , Bolton Scott J. , Levin Steven M.
Published: July 2020

Jupiter lightning discharges produce various kinds of phenomena including radio wave pulses at different frequencies. On 6 April 2019, the Juno Waves instrument captured an extraordinary series of radio pulses at frequencies below 150 kHz on timescales of submilliseconds. Quasi‐simultaneous multi‐instrument data show that the locations of their magnetic footprints are very close to the locations of ultrahigh frequency (UHF) sferics recorded by the Juno MWR instrument. Hubble Space Telescope images show that the signature of active convection includes cloud‐free clearings, in addition to the convective towers and deep water clouds that were also recognized in previous spacecraft observations of lightning source regions. Furthermore, the detections of 17 very low frequency/low‐frequency (VLF/LF) radio pulses suggest a minimum duration of lightning processes on the order of submilliseconds. These observations provide new constraints on the physical properties of Jupiter lightning.
Critical Zone Storage Controls on the Water Ages of Ecohydrological Outputs
Authors: Kuppel S. , Tetzlaff D. , Maneta M. P. , Soulsby C.
Published: July 2020

Spatially explicit knowledge of the origins of water resources for ecosystems and rivers is challenging when using tracer data alone. We use simulations from a spatially distributed model calibrated by extensive ecohydrological data sets in a small, energy‐limited catchment, where hillslope‐riparian dynamics are broadly representative of humid boreal headwater catchments that are experiencing rapid environmental transition. We hypothesize that in addition to wetness status, landscape heterogeneity modulates the water pathways that sustain ecosystem function and streamflows. Simulations show that catchment storage inversely controls stream water ages year‐round, but only during the drier seasons for transpiration and soil evaporation. The ages of these evaporative outputs depend much less on wetness status in the oft‐saturated riparian soils than on the freely draining hillslopes that subsidize them. This work highlights the need to consider local dynamics and time‐changing lateral heterogeneities when interpreting the ages, and thus the vulnerability, of water resources feeding streams and ecosystems in landscapes.
Observation of High‐Energy Electrons Precipitated by NWC Transmitter From PROBA‐V Low‐Earth Orbit Satellite
Authors: Cunningham G. S. , Botek E. , Pierrard V. , Cully C. , Ripoll J.‐F.
Published: July 2020

The very low‐frequency transmitter in the Northwest Cape of Australia (NWC) has previously been observed to pitch‐angle scatter electrons with energies from 30–400 keV, creating enhanced fluxes measured by low‐Earth orbiting (LEO) satellites. Here we use observations from the Energetic Particle Telescope on PROBA‐V. We compare the measured flux, as a function of local magnetic field strength, when the NWC transmitter is “on” versus “off,” and find enhanced fluxes only when NWC is “on” and located on the nightside. The enhanced fluxes occur in the population gradually transitioning from “permanently trapped” to “quasi‐trapped.” We show that electrons up to 800 keV, substantially higher energy than previously studied, are scattered by resonant interactions with NWC to produce enhanced fluxes. The enhanced fluxes appear at multiple L‐shells for each energy channel, consistent with resonance conditions at distinct wave normal angles, that indicate ducted interactions at L < 1.55 and unducted interactions at L > 1.65.
The Effect of a Liquid Phase on Force Distribution During Deformation in a Granular System
Authors: Ladd Christopher R. , Reber Jacqueline E.
Published: July 2020

Two‐phase systems, where one phase is solid and the other is fluid, are widespread in nature. Examples include reservoir rocks holding vital fluids like water or petroleum, slurries of partially crystallized magmas, fluids migrating along faults filled with fault gouge, and even the semibrittle crust. Previous studies of two‐phase systems have shown that the fluid phase plays an important role in deformation localization and dynamics (e.g., Higashi & Sumita, 2009, https://doi.org/10.1029/2008JB005999; Reber et al., 2014, https://doi.org/10.1002/2014GL059832). Here, we present results from experiments investigating the influence of a fluid phase on force distribution in a granular media during simple shear. We use photoelastic polyurethane discs as the granular or solid phase and a linear viscous silicone as the fluid phase. The photoelastic property of the discs allows for direct observation and measurement of force magnitude and distribution. We compare the two‐phase experiments to granular experiments without silicone. The addition and percentage of the fluid phase has a strong impact on the force distribution and the overall force chain orientations. In the two‐phase system, the force chains form parallel to the shear plane and only rotate to the principal stress direction with an increase in strain. Locally, the fluid phase can support forces and terminate force chains over an extended period of time. Our results are in line with findings from numerical studies investigating the formation of slow slip events, proposing that these events are the result of dynamic interactions between solid and viscous phases.
Rough Correlations: Meta‐Analysis of Roughness Measures in Gravel Bed Rivers
Authors: Chen Xingyu , Hassan Marwan A. , An Chenge , Fu Xudong
Published: July 2020

Bed roughness height (k) is a key parameter for velocity prediction in open‐channel flows. There is not yet a firm consensus about whether characteristic particle size D84 or
(standard deviation of the channel thalweg) better describes k in gravel bed streams. A data set of 1,788 flume and 713 field measurements with a wide range of channel morphologies and flow conditions were compiled to test whether D84 or
is a better descriptor of k and to explore the influence of several controls on flow resistance variation. Tests were performed using four well‐known flow resistance equations. The results consistently show that
outperforms D84 in predicting velocity and the Smart and Jäggi equation, with
as k, outperforms other equations. The data set was grouped based on R/k (R is the hydraulic radius), channel morphologies, and study sites.
performs better than D84 as a measure of k in all morphologies and much better for channels with large instream wood. The analysis shows R/k is a major control on resistance variation as
contains more site‐specific information like bed structure. The topography measurements for step‐pool channels should at least contain measurements on key roughness elements like steps. For gravel‐dune or plane‐bed channels, the proper resolution should be higher than 1/2 dune wavelength and 2D84, respectively. The choice of proper reach length relates to both R/k and roughness type. Further, hydraulic geometry functions with either D84 or
as k are proposed, and the relation between the two metrics is discussed.
A scalable method for preparing Cu electrocatalysts that convert CO2 into C2+ products
Authors: Kim Taehee , Palmore G. Tayhas R.
Published: July 2020

Development of efficient catalysts for selective electroreduction of CO2 to high-value products is essential for the deployment of carbon utilization technologies. Here we present a scalable method for preparing Cu electrocatalysts that favor CO2 conversion to C2+ products with faradaic efficiencies up to 72%. Grazing-incidence X-ray diffraction data confirms that anodic halogenation of electropolished Cu foils in aqueous solutions of KCl, KBr, or KI creates surfaces of CuCl, CuBr, or CuI, respectively. Scanning electron microscopy and energy dispersive X-ray spectroscopy studies show that significant changes to the morphology of Cu occur during anodic halogenation and subsequent oxide-formation and reduction, resulting in catalysts with a high density of defect sites but relatively low roughness. This work shows that efficient conversion of CO2 to C2+ products requires a Cu catalyst with a high density of defect sites that promote adsorption of carbon intermediates and C–C coupling reactions while minimizing roughness.
Dually modulated photonic crystals enabling high-power high-beam-quality two-dimensional beam scanning lasers
Authors: Sakata Ryoichi , Ishizaki Kenji , De Zoysa Menaka , Fukuhara Shin , Inoue Takuya , Tanaka Yoshinori , Iwata Kintaro , Hatsuda Ranko , Yoshida Masahiro , Gelleta John , Noda Susumu
Published: July 2020

Mechanical-free, high-power, high-beam-quality two-dimensional (2D) beam scanning lasers are in high demand for various applications including sensing systems for smart mobility, object recognition systems, and adaptive illuminations. Here, we propose and demonstrate the concept of dually modulated photonic crystals to realize such lasers, wherein the positions and sizes of the photonic-crystal lattice points are modulated simultaneously. We show using nano-antenna theory that this photonic nanostructure is essential to realize 2D beam scanning lasers with high output power and high beam quality. We also fabricate an on-chip, circuit-driven array of dually modulated photonic-crystal lasers with a 10 × 10 matrix configuration having 100 resolvable points. Our device enables the scanning of laser beams over a wide range of 2D directions in sequence and in parallel, and can be flexibly designed to meet application-specific demands.
Heat and charge transport in H2O at ice-giant conditions from ab initio molecular dynamics simulations
Authors: Grasselli Federico , Stixrude Lars , Baroni Stefano
Published: July 2020

The impact of the inner structure and thermal history of planets on their observable features, such as luminosity or magnetic field, crucially depends on the poorly known heat and charge transport properties of their internal layers. The thermal and electric conductivities of different phases of water (liquid, solid, and super-ionic) occurring in the interior of ice giant planets, such as Uranus or Neptune, are evaluated from equilibrium ab initio molecular dynamics, leveraging recent progresses in the theory and data analysis of transport in extended systems. The implications of our findings on the evolution models of the ice giants are briefly discussed.
A rare variant of African ancestry activates 8q24 lncRNA hub by modulating cancer associated enhancer
Authors: Walavalkar Kaivalya , Saravanan Bharath , Singh Anurag Kumar , Jayani Ranveer Singh , Nair Ashwin , Farooq Umer , Islam Zubairul , Soota Deepanshu , Mann Rajat , Shivaprasad Padubidri V. , Freedman Matthew L. , Sabarinathan Radhakrishnan , Haiman Christopher A. , Notani Dimple
Published: July 2020

Genetic variation at the 8q24 locus is linked with the greater susceptibility to prostate cancer in men of African ancestry. One such African ancestry specific rare variant, rs72725854 (A>G/T) (~6% allele frequency) has been associated with a ~2-fold increase in prostate cancer risk. However, the functional relevance of this variant is unknown. Here we show that the variant rs72725854 is present in a prostate cancer-specific enhancer at 8q24 locus. Chromatin-conformation capture and dCas9 mediated enhancer blocking establish a direct regulatory link between this enhancer and lncRNAs PCAT1, PRNCR1 and PVT1. The risk allele (‘T’) is associated with higher expression of PCAT1, PVT1 and c-myc in prostate tumors. Further, enhancer with the risk allele gains response to androgen stimulation by recruiting the transcription factor SPDEF whereas, non-risk alleles remain non-responsive. Elevated expression of these lncRNAs and c-myc in risk allele carriers may explain their greater susceptibility to prostate cancer.
Pre-initiation and elongation structures of full-length La Crosse virus polymerase reveal functionally important conformational changes
Authors: Arragain Benoît , Effantin Grégory , Gerlach Piotr , Reguera Juan , Schoehn Guy , Cusack Stephen , Malet Hélène
Published: July 2020

Bunyavirales is an order of segmented negative-strand RNA viruses comprising several life-threatening pathogens against which no effective treatment is currently available. Replication and transcription of the RNA genome constitute essential processes performed by the virally encoded multi-domain RNA-dependent RNA polymerase. Here, we describe the complete high-resolution cryo-EM structure of La Crosse virus polymerase. It reveals the presence of key protruding C-terminal domains, notably the cap-binding domain, which undergoes large movements related to its role in transcription initiation, and a zinc-binding domain that displays a fold not previously observed. We capture the polymerase structure at pre-initiation and elongation states, uncovering the coordinated movement of the priming loop, mid-thumb ring linker and lid domain required for the establishment of a ten-base-pair template-product RNA duplex before strand separation into respective exit tunnels. These structural details and the observed dynamics of key functional elements will be instrumental for structure-based development of polymerase inhibitors.
Supramolecular double-stranded Archimedean spirals and concentric toroids
Authors: Sasaki Norihiko , Mabesoone Mathijs F. J. , Kikkawa Jun , Fukui Tomoya , Shioya Nobutaka , Shimoaka Takafumi , Hasegawa Takeshi , Takagi Hideaki , Haruki Rie , Shimizu Nobutaka , Adachi Shin-ichi , Meijer E. W. , Takeuchi Masayuki , Sugiyasu Kazunori
Published: July 2020

Connecting molecular-level phenomena to larger scales and, ultimately, to sophisticated molecular systems that resemble living systems remains a considerable challenge in supramolecular chemistry. To this end, molecular self-assembly at higher hierarchical levels has to be understood and controlled. Here, we report unusual self-assembled structures formed from a simple porphyrin derivative. Unexpectedly, this formed a one-dimensional (1D) supramolecular polymer that coiled to give an Archimedean spiral. Our analysis of the supramolecular polymerization by using mass-balance models suggested that the Archimedean spiral is formed at high concentrations of the monomer, whereas other aggregation types might form at low concentrations. Gratifyingly, we discovered that our porphyrin-based monomer formed supramolecular concentric toroids at low concentrations. Moreover, a mechanistic insight into the self-assembly process permitted a controlled synthesis of these concentric toroids. This study both illustrates the richness of self-assembled structures at higher levels of hierarchy and demonstrates a topological effect in noncovalent synthesis.
Rapid and high-resolution patterning of microstructure and composition in organic semiconductors using ‘molecular gates’
Authors: Perevedentsev Aleksandr , Campoy-Quiles Mariano
Published: July 2020

Photolithography has been a major enabling tool for miniaturisation of silicon devices that underpinned the electronics revolution. Rapid, high-resolution patterning of key material characteristics would, similarly, accelerate the advent of molecular electronics and photonics. Here we advance a versatile approach employing local diffusion of functional small-molecular compounds through a solution-processed ‘molecular gate’ interlayer. Diffusion is activated using laser light or solvent vapour jets―a process that can be finely modulated down to molecule-on-demand deposition precision with almost photolithographic resolution (<5 μm) and speeds (3 mm s–1). Examples of principal pattern types are presented including molecular conformation for integrated photonics; chain orientation for polarised security features and micro-engineered electronics; and doping with local conductivity values >3 S cm–1 for improved electronic devices. Finally, we demonstrate the unique capability for one-step patterning of multiple functionalities by spatially modulating composition in ternary blends, leading to locally tunable photoluminescence from blue to red.
Unimolecularly thick monosheets of vinyl polymers fabricated in metal–organic frameworks
Authors: Hosono Nobuhiko , Mochizuki Shuto , Hayashi Yuki , Uemura Takashi
Published: July 2020

Polymers with two-dimensional (2D) network topologies are currently gaining significant attention due to their unique properties that originate from their regulated conformations. However, in contrast to conventional 1D- and 3D-networked macromolecules, the synthesis of such 2D networks provides challenges for polymer chemists because of the nature of the networking polymerisation reaction, which occurs in a spatially random fashion when conventional solution-phase synthesis is performed. Here we report a versatile synthesis of polymeric monosheets with unimolecularly thick networking architectures by exploiting the 2D nanospaces of metal–organic frameworks (MOFs) as reaction templates. Crosslinking radical polymerisation in the 2D nanospaces of pillared-layer-type MOFs affords monosheets of typical vinyl polymers and can be carried out on the gram scale. Remarkably, the prepared polymer monosheets are highly soluble in organic solvents and show atypical thermal and rheological properties that result from their 2D-regulated conformations that cannot be adopted by their 1D or 3D analogues.
A transition to sustainable ocean governance
Authors: Brodie Rudolph Tanya , Ruckelshaus Mary , Swilling Mark , Allison Edward H. , Österblom Henrik , Gelcich Stefan , Mbatha Philile
Published: July 2020

Human wellbeing relies on the Biosphere, including natural resources provided by ocean ecosystems. As multiple demands and stressors threaten the ocean, transformative change in ocean governance is required to maintain the contributions of the ocean to people. Here we illustrate how transition theory can be applied to ocean governance. We demonstrate how current economic and social systems can adapt to existing pressures and shift towards ocean stewardship through incorporation of niche innovations within and across economic sectors and stakeholder communities. These novel approaches support an emergent but purposeful transition and suggest a clear path to a thriving and vibrant relationship between humans and the ocean. Oceans provide important natural resources, but the management and governance of the ocean is complex and the ecosystem is suffering as a result. The authors discuss current barriers to sustainable ocean governance and suggest pathways forward.
Calcium isotopic ecology of Turkana Basin hominins
Authors: Martin Jeremy E. , Tacail Théo , Braga José , Cerling Thure E. , Balter Vincent
Published: July 2020

Diet is a major driver of hominin evolution, but most of the geochemical evidence relies on carbon isotopes (δ13C). Here, we report enamel stable calcium isotope (δ44/42Ca) values against δ13C values for several hominins and co-existing primates in the Turkana Basin area, circa 4 to 2 Ma. Australopithecus anamensis clusters with mammal browsers, Kenyanthropus platyops is distinct from A. anamensis in foraging into more open environments and the coexisting Theropithecus brumpti encompasses both the grazer and omnivore/carnivore domains. Early Homo is remarkable for its wide distribution in δ44/42Ca values, possibly reflecting omnivorous and opportunistic preferences. Paranthropus boisei is uniquely distributed in the δ13C versus δ44/42Ca iso-space being distinct from all other hominins from the Turkana Basin area as well as from the co-existing Theropithecus oswaldi. Several hypotheses are explored to discuss the unique δ44/42Ca values of Paranthropus boisei including significant differences observed with δ44/42Ca values recently reported for P. robustus from South Africa, questioning the monophyly of this genus.
Shaping caustics into propagation-invariant light
Authors: Zannotti Alessandro , Denz Cornelia , Alonso Miguel A. , Dennis Mark R.
Published: July 2020

Structured light has revolutionized optical particle manipulation, nano-scaled material processing, and high-resolution imaging. In particular, propagation-invariant light fields such as Bessel, Airy, or Mathieu beams show high robustness and have a self-healing nature. To generalize such beneficial features, these light fields can be understood in terms of caustics. However, only simple caustics have found applications in material processing, optical trapping, or cell microscopy. Thus, these technologies would greatly benefit from methods to engineer arbitrary intensity shapes well beyond the standard families of caustics. We introduce a general approach to arbitrarily shape propagation-invariant beams by smart beam design based on caustics. We develop two complementary methods, and demonstrate various propagation-invariant beams experimentally, ranging from simple geometric shapes to complex image configurations such as words. Our approach generalizes caustic light from the currently known small subset to a complete set of tailored propagation-invariant caustics with intensities concentrated around any desired curve.